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  Subjects -> BIOLOGY (Total: 3086 journals)
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BIOLOGY (1462 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 21)
Achievements in the Life Sciences     Open Access   (Followers: 5)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 23)
Acta Biologica Colombiana     Open Access   (Followers: 7)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 4)
Acta Biologica Sibirica     Open Access  
Acta Biomaterialia     Hybrid Journal   (Followers: 27)
Acta Biotheoretica     Hybrid Journal   (Followers: 4)
Acta Chiropterologica     Full-text available via subscription   (Followers: 6)
acta ethologica     Hybrid Journal   (Followers: 4)
Acta Limnologica Brasiliensia     Open Access   (Followers: 3)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Musei Silesiae, Scientiae Naturales : The Journal of Silesian Museum in Opava     Open Access  
Acta Neurobiologiae Experimentalis     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 10)
Acta Scientiarum. Biological Sciences     Open Access   (Followers: 2)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
Actualidades Biológicas     Open Access   (Followers: 1)
Advanced Health Care Technologies     Open Access   (Followers: 4)
Advanced Studies in Biology     Open Access  
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Bioinformatics     Open Access   (Followers: 17)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 7)
Advances in Cell Biology     Open Access   (Followers: 24)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 10)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 18)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 6)
Advances in Genome Biology     Full-text available via subscription   (Followers: 7)
Advances in High Energy Physics     Open Access   (Followers: 18)
Advances in Human Biology     Open Access   (Followers: 2)
Advances in Life Science and Technology     Open Access   (Followers: 14)
Advances in Life Sciences     Open Access   (Followers: 6)
Advances in Marine Biology     Full-text available via subscription   (Followers: 14)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3)
Advances in Regenerative Biology     Open Access   (Followers: 1)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Virus Research     Full-text available via subscription   (Followers: 5)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 6)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 1)
Ageing Research Reviews     Hybrid Journal   (Followers: 9)
Aging Cell     Open Access   (Followers: 11)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
AJP Cell Physiology     Full-text available via subscription   (Followers: 14)
AJP Endocrinology and Metabolism     Full-text available via subscription   (Followers: 23)
AJP Lung Cellular and Molecular Physiology     Full-text available via subscription   (Followers: 3)
Al-Kauniyah : Jurnal Biologi     Open Access  
Alasbimn Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Biology Teacher     Full-text available via subscription   (Followers: 14)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 8)
American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Human Biology     Hybrid Journal   (Followers: 13)
American Journal of Medical and Biological Research     Open Access   (Followers: 8)
American Journal of Plant Sciences     Open Access   (Followers: 18)
American Journal of Primatology     Hybrid Journal   (Followers: 14)
American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 70)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 10)
Anatomical Science International     Hybrid Journal   (Followers: 2)
Animal Cells and Systems     Hybrid Journal   (Followers: 4)
Annales de Limnologie - International Journal of Limnology     Hybrid Journal   (Followers: 1)
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales UMCS, Biologia     Open Access   (Followers: 1)
Annals of Applied Biology     Hybrid Journal   (Followers: 7)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18)
Annals of Human Biology     Hybrid Journal   (Followers: 5)
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 15)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 23)
Annual Review of Cancer Biology     Full-text available via subscription   (Followers: 1)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 37)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 23)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 22)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antibiotics     Open Access   (Followers: 9)
Antioxidants     Open Access   (Followers: 4)
Antioxidants & Redox Signaling     Hybrid Journal   (Followers: 8)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apidologie     Hybrid Journal   (Followers: 4)
Apmis     Hybrid Journal   (Followers: 1)
APOPTOSIS     Hybrid Journal   (Followers: 8)
Applied Bionics and Biomechanics     Open Access   (Followers: 8)
Applied Vegetation Science     Full-text available via subscription   (Followers: 10)
Aquaculture Environment Interactions     Open Access   (Followers: 2)
Aquaculture International     Hybrid Journal   (Followers: 22)
Aquaculture Reports     Open Access   (Followers: 3)
Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society     Open Access   (Followers: 6)
Aquatic Biology     Open Access   (Followers: 5)
Aquatic Ecology     Hybrid Journal   (Followers: 32)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 14)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 21)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biological Sciences     Open Access  
Archives of Biomedical Sciences     Open Access   (Followers: 7)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Archives of Natural History     Hybrid Journal   (Followers: 6)
Archives of Oral Biology     Hybrid Journal   (Followers: 2)
Archives of Virology     Hybrid Journal   (Followers: 5)
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2)
Arid Ecosystems     Hybrid Journal   (Followers: 2)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arquivos do Museu Dinâmico Interdisciplinar     Open Access  
Arthropod Structure & Development     Hybrid Journal   (Followers: 2)
Arthropods     Open Access   (Followers: 1)
Artificial DNA: PNA & XNA     Hybrid Journal   (Followers: 3)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 3)
Asian Journal of Biodiversity     Open Access   (Followers: 4)
Asian Journal of Biological Sciences     Open Access   (Followers: 3)
Asian Journal of Cell Biology     Open Access   (Followers: 5)
Asian Journal of Developmental Biology     Open Access   (Followers: 2)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 3)
Asian Journal of Nematology     Open Access   (Followers: 4)
Asian Journal of Poultry Science     Open Access   (Followers: 3)
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 6)
Autophagy     Hybrid Journal   (Followers: 2)
Avian Biology Research     Full-text available via subscription   (Followers: 4)
Avian Conservation and Ecology     Open Access   (Followers: 11)
Bacteriology Journal     Open Access   (Followers: 1)
Bacteriophage     Full-text available via subscription   (Followers: 3)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Plant Taxonomy     Open Access  
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Berita Biologi     Open Access   (Followers: 1)
Between the Species     Open Access   (Followers: 1)
Bio Tribune Magazine     Hybrid Journal  
BIO Web of Conferences     Open Access  
BIO-Complexity     Open Access  
Bio-Grafía. Escritos sobre la Biología y su enseñanza     Open Access  
Bioanalytical Reviews     Hybrid Journal   (Followers: 2)
Biocatalysis and Biotransformation     Hybrid Journal   (Followers: 6)
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 15)
Biochimie     Hybrid Journal   (Followers: 7)
BioControl     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodemography and Social Biology     Hybrid Journal  
BioDiscovery     Open Access   (Followers: 2)
Biodiversitas : Journal of Biological Diversity     Open Access  
Biodiversity : Research and Conservation     Open Access   (Followers: 26)
Biodiversity and Natural History     Open Access   (Followers: 6)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     Open Access   (Followers: 1)
Biodiversity Information Science and Standards     Open Access  
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Bioelectromagnetics     Hybrid Journal   (Followers: 1)
Bioenergy Research     Hybrid Journal   (Followers: 2)
Bioengineering and Bioscience     Open Access   (Followers: 1)
BioEssays     Hybrid Journal   (Followers: 10)
Bioethics     Hybrid Journal   (Followers: 14)
BioéthiqueOnline     Open Access  
Biofabrication     Hybrid Journal   (Followers: 5)
Biofilms     Full-text available via subscription   (Followers: 1)
Biogeosciences (BG)     Open Access   (Followers: 10)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 2)
Bioinformatics     Hybrid Journal   (Followers: 281)
Bioinformatics and Biology Insights     Open Access   (Followers: 11)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 7)
Biointerphases     Open Access   (Followers: 1)
Biojournal of Science and Technology     Open Access  
Biologia     Hybrid Journal  
Biologia on-line : Revista de divulgació de la Facultat de Biologia     Open Access  
Biological Bulletin     Partially Free   (Followers: 5)
Biological Control     Hybrid Journal   (Followers: 4)
Biological Invasions     Hybrid Journal   (Followers: 18)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 18)
Biological Letters     Open Access   (Followers: 5)
Biological Procedures Online     Open Access  
Biological Psychiatry     Hybrid Journal   (Followers: 45)
Biological Psychology     Hybrid Journal   (Followers: 7)
Biological Research     Open Access  
Biological Rhythm Research     Hybrid Journal   (Followers: 2)
Biological Theory     Hybrid Journal   (Followers: 2)
Biological Trace Element Research     Hybrid Journal  
Biologicals     Full-text available via subscription   (Followers: 9)
Biologics: Targets & Therapy     Open Access   (Followers: 1)
Biologie Aujourd'hui     Full-text available via subscription  
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 40)
Biologija     Open Access  
Biology     Open Access   (Followers: 3)

        1 2 3 4 5 6 7 8 | Last

Journal Cover Aquatic Toxicology
  [SJR: 1.671]   [H-I: 105]   [21 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0166-445X - ISSN (Online) 1879-1514
   Published by Elsevier Homepage  [3175 journals]
  • Effects of environmentally relevant sub-chronic atrazine concentrations on
           African clawed frog (Xenopus laevis) survival, growth and male gonad
           development
    • Authors: Cornelius Rimayi; David Odusanya; Jana M. Weiss; Jacob de Boer; Luke Chimuka; Felix Mbajiorgu
      Pages: 1 - 11
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Cornelius Rimayi, David Odusanya, Jana M. Weiss, Jacob de Boer, Luke Chimuka, Felix Mbajiorgu
      Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg L−1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 μg L−1 atrazine exposed tadpoles (p < 0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 μg L−1 and 500 μg L−1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 μg L−1 cause significant mortality in tadpoles, while concentrations ≥200 μg L−1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.028
      Issue No: Vol. 199 (2018)
       
  • Oxidative stress and mitochondrial dysfunction mediated Cd-induced hepatic
           lipid accumulation in zebrafish Danio rerio
    • Authors: Ya-Xiong Pan; Zhi Luo; Mei-Qing Zhuo; Chuan-Chuan Wei; Guang-Hui Chen; Yu-Feng Song
      Pages: 12 - 20
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Ya-Xiong Pan, Zhi Luo, Mei-Qing Zhuo, Chuan-Chuan Wei, Guang-Hui Chen, Yu-Feng Song
      The present study was performed to determine the effect of waterborne CdCl2 exposure influencing lipid deposition and metabolism, oxidative stress and mitochondrial dysfunction, and explore the underlying molecular mechanism of cadmium (Cd)-induced disorder of hepatic lipid metabolism in fish. To this end, adult zebrafish were exposed to three waterborne CdCl2 concentrations (0(control), 5 and 25 μg Cd/l, respectively) for 30 days. Lipid accumulation, the activities of enzymes related to lipid metabolism and oxidative stress, as well as the expression level of genes involved in lipid metabolism and mitophagy were determined in the liver of zebrafish. Waterborne CdCl2 exposure increased hepatic triglyceride (TG) and Cd accumulation, the activities of fatty acid synthase (FAS), 6-phosphogluconate dehydrogenase (6PGD), glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME), and the mRNA level of fatty acid synthase (fas), acetyl-CoA carboxylase alpha (acaca), glucose 6-phosphate dehydrogenase (g6pd) and malic enzyme (me), but reduced the mRNA level of carnitine palmitoyl transferase 1 (cpt1), hormone-sensitive lipase alpha (hsla), and adipose triacylglyceride lipase (atgl). The activities of superoxide dismutase (SOD), glutathoinine peroxidase (GPx) and cytochrome c oxidase (COX) and the ATP level were significantly reduced after CdCl2 exposure. CdCl2 exposure significantly increased the mRNA level of genes (microtubule-associated protein light chain 3 alpha (lc3a), PTEN-induced putative kinase 1 (pink1), NIP3-like protein X (nix) and PARKIN (parkin)) related to mitophagy. To elucidate the mechanism, reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) and the mitochondrial permeability transition (MPT) inhibitor cyclosporine A (CsA) were used to verify the role of ROS and mitochondrial dysfunction in Cd-induced disorder of lipid metabolism. NAC pretreatment reversed the Cd-induced up-regulation of TG accumulation and activities of lipogenic enzymes, and the Cd-induced down-regulation of mRNA levels of lipolytic genes. Meanwhile, NAC pretreatment also blocked the mitochondrial membrane potential (MMP) collapse and decreased the ATP level, suggesting that ROS played a crucial role in regulating the Cd-induced mitochondrial dysfunction. Taken together, our findings, for the first time, highlight the importance of the oxidative stress and mitochondrial dysfunction in Cd-induced disorder of hepatic lipid metabolism, which proposed a novel mechanism for elucidating metal element exposure inducing the disorder of lipid metabolism in vertebrates.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.017
      Issue No: Vol. 199 (2018)
       
  • Effects of bisphenol A and its analogs bisphenol F and S on life
           parameters, antioxidant system, and response of defensome in the marine
           rotifer Brachionus koreanus
    • Authors: Jun Chul Park; Min-Chul Lee; Deok-Seo Yoon; Jeonghoon Han; Moonkoo Kim; Un-Ki Hwang; Jee-Hyun Jung; Jae-Seong Lee
      Pages: 21 - 29
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Jun Chul Park, Min-Chul Lee, Deok-Seo Yoon, Jeonghoon Han, Moonkoo Kim, Un-Ki Hwang, Jee-Hyun Jung, Jae-Seong Lee
      To understand the adverse outcome in response to bisphenol A and its analogs bisphenol F and S (BPA, BPF, and BPS), we examined acute toxicity, life parameter, and defensome in the marine rotifer Brachionus koreanus. Among the bisphenol analogs, BPA showed the highest acute toxicity and then BPF and BPS, accordingly in the view of descending magnitude of toxicity. In life parameters including life span and reproduction, BPA, BPF, and BPS were found to cause adverse effect. Both intracellular ROS level and GST activity were significantly increased (P < 0.05) in response to each dosage of bisphenol analogs exposures. In response to bisphenol analogs, defensomes of phase I, II, and III detoxification mechanism demonstrated inverse relationship between the lipophilicity of bisphenol analogs and the expression patterns of defensomes. BPA and BPF were found to have significant modulation (P < 0.05) in the expression of cytochrome P450 (CYP) and GST genes. In phase III, BPS with comparatively lower lipophilicity demonstrated highly diversified expressional pattern, suggesting that BPS is likely caused less toxicity compared to BPA and BPF. In this study, via phase I, II, and III detoxification mechanism, bisphenol A and its analogs F and S demonstrated specific detoxification mechanism in rotifer.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.024
      Issue No: Vol. 199 (2018)
       
  • Physiological impacts and bioaccumulation of dietary Cu and Cd in a model
           teleost: The Amazonian tambaqui (Colossoma macropomum)
    • Authors: Marina Giacomin; Gisele C. Vilarinho; Katia F. Castro; Márcio Ferreira; Rafael M. Duarte; Chris M. Wood; Adalberto L. Val
      Pages: 30 - 45
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Marina Giacomin, Gisele C. Vilarinho, Katia F. Castro, Márcio Ferreira, Rafael M. Duarte, Chris M. Wood, Adalberto L. Val
      Increasing anthropogenic activities in the Amazon have led to elevated metals in the aquatic environment. Since fish are the main source of animal protein for the Amazonian population, understanding metal bioaccumulation patterns and physiological impacts is of critical importance. Juvenile tambaqui, a local model species, were exposed to chronic dietary Cu (essential, 500 μg Cu/g food) and Cd (non-essential, 500 μg Cd/g food). Fish were sampled at 10–14, 18–20 and 33–36 days of exposure and the following parameters were analyzed: growth, voluntary food consumption, conversion efficiency, tissue-specific metal bioaccumulation, ammonia and urea-N excretion, O2 consumption, Pcrit, hypoxia tolerance, nitrogen quotient, major blood plasma ions and metabolites, gill and gut enzyme activities, and in vitro gut fluid transport. The results indicate no ionoregulatory impacts of either of the metal-contaminated diets at gill, gut, or plasma levels, and no differences in plasma cortisol or lactate. The Cd diet appeared to have suppressed feeding, though overall tank growth was not affected. Bioaccumulation of both metals was observed. Distinct tissue-specific and time-specific patterns were seen. Metal burdens in the edible white muscle remained low. Overall, physiological impacts of the Cu diet were minimal. However dietary Cd increased hypoxia tolerance, as evidenced by decreased Pcrit, increased time to loss of equilibrium, a lack of plasma glucose elevation, decreased plasma ethanol, and decreased NQ during hypoxia. Blood O2 transport characteristics (P50, Bohr coefficient, hemoglobin, hematocrit) were unaffected, suggesting that tissue level changes in metabolism accounted for the greater hypoxia tolerance in tambaqui fed with a Cd-contaminated diet.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.021
      Issue No: Vol. 199 (2018)
       
  • Does fluoxetine exposure affect hypoxia tolerance in the Gulf toadfish,
           Opsanus beta'
    • Authors: Molly H.B. Amador; Kevin L. Schauer; M. Danielle McDonald
      Pages: 55 - 64
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Molly H.B. Amador, Kevin L. Schauer, M. Danielle McDonald
      Due to ineffective wastewater treatment technologies, pharmaceuticals such as the selective serotonin reuptake inhibitors (SSRIs)—a common class of antidepressants which inhibit the serotonin transporter (SERT)—can be found in surface waters and marine receiving waters near wastewater effluents. Understanding how exposure to these chemicals might impact non-target organisms, especially combined with other environmental stressors like hypoxia, is essential in order to thoroughly evaluate environmental risk. It was hypothesized that both acute and chronic exposure to the SSRI fluoxetine (FLX) would interfere with the metabolic hypoxia response of the Gulf toadfish, Opsanus beta. Here we demonstrate that acute intraperitoneal treatment with 50 μg g−1 FLX significantly reduces the regulation index, or degree of metabolic regulation, in toadfish. Acute FLX exposure significantly reduced SERT mRNA expression in the first and third gill arches, but mRNA expression was not affected in heart tissues or in the second gill arch. In contrast, the regulation index was unaffected by 14–17 day waterborne FLX exposure to environmentally relevant (0.01 μg L−1) and approximately 1000-fold higher (8.5 μg L−1) concentrations. However, the higher concentration was sufficient to induce a systemic elevation in plasma serotonin concentrations. Chronic FLX exposure did not alter SERT mRNA expression in heart or gill tissues. The results of this study implicate the involvement of 5-HT pathways in hypoxia tolerance but demonstrate that current environmental levels of FLX are insufficient to impair the metabolic hypoxia response in marine fish.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.023
      Issue No: Vol. 199 (2018)
       
  • Effects of oil spill response technologies on the physiological
           performance of the Arctic copepod Calanus glacialis
    • Authors: Kirstine Toxværd; Marina Pančić; Helene O. Eide; Janne E. Søreide; Camille Lacroix; Stéphane Le Floch; Morten Hjorth; Torkel Gissel Nielsen
      Pages: 65 - 76
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Kirstine Toxværd, Marina Pančić, Helene O. Eide, Janne E. Søreide, Camille Lacroix, Stéphane Le Floch, Morten Hjorth, Torkel Gissel Nielsen
      A mesocosm study with oil in ice was performed in Van Mijenfjorden in Svalbard to compare effects of the oil spill responses (OSR) in situ burning, chemical dispersion and natural attenuation on the physiological performance of the Arctic copepod Calanus glacialis. Seawater collected from the mesocosms in winter and spring was used in laboratory incubation experiments, where effects on fecal pellet production, egg production and hatching success were investigated over a period of 14 days. Polycyclic aromatic hydrocarbon (PAH) seawater concentrations were lowest in winter. Brine channel formation in spring resulted in an 18 times increase in PAH concentration in the chemical dispersion treatment (1.67 μg L−1), and a 3 fold increase in the natural attenuation (0.36 μg L−1) and in situ burning (0.04 μg L−1) treatments. The physiological performance of female C. glacialis was unaffected by the PAH seawater concentrations. However, a higher mortality and deformity of nauplii was observed in the chemical dispersion treatment, highlighting the importance of considering secondary effects on next generation in future environmental risk assessment of OSR. This study shows that during the ice-covered period, chemical dispersion of oil spills leads to higher PAH exposure than natural attenuation and in situ burning, with potential consequences for recruitment of Arctic copepods.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.032
      Issue No: Vol. 199 (2018)
       
  • Part B: Morphometric and transcriptomic responses to sub-chronic exposure
           to the polycyclic aromatic hydrocarbon phenanthrene in the fathead minnow
           (Pimephales promelas)
    • Authors: Jennifer R. Loughery; Karen A. Kidd; Angella Mercer; Chris J. Martyniuk
      Pages: 77 - 89
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Jennifer R. Loughery, Karen A. Kidd, Angella Mercer, Chris J. Martyniuk
      Phenanthrene is a tricyclic polycyclic aromatic hydrocarbon and environmental contaminant found in high concentrations around urban catchments and in the vicinity of oil extraction activities. Fish exposed to phenanthrene can exhibit altered reproductive hormone profiles and/or differences within gonadosomatic index and altered gamete proportions, but the mechanisms underlying these changes are not fully understood. In this study, we conducted a sub-chronic bioassay and measured transcriptional responses in the liver, the major tissue involved in generating lipids for oocyte growth. Adult male and female fathead minnow (Pimephales promelas) were exposed to an average measured concentration of 202 μg phenanthrene/L for a 7 week period. Condition factor was reduced in both males and females, while female fish also showed decreased gonadosomatic index relative to control females. In females exposed to phenanthrene, perinucleolar proportions were increased ∼1.9-fold relative to the control group whereas the proportions of vitellogenic oocytes decreased ∼8.8 fold. In males exposed to phenanthrene, spermatogonia proportions were increased ∼2.3 fold in testicular tissues compared to control fish. Thus, gametes were at an earlier stage of maturation in phenanthrene-treated fish compared to controls. However, no differences were detected in the production of 17β-estradiol or testosterone from the gonad in either sex. Catalase activity was also assessed in the liver as a measure of oxidative stress and this biomarker did not change in activity in either sex. In addition to endpoints in the ovary, the female hepatic transcriptome was measured, as this tissue produces lipids for oocyte maturation. Transcriptomic responses to phenanthrene exposure suggested a reduction in vitellogenin mRNA, and lipid metabolism and immune system pathways. Comparisons of hepatic transcriptome responses with Part A (72 h phenanthrene exposure) showed that energy homeostasis pathways were consistently altered following phenanthrene exposure over multiple durations and concentrations. We suggest that altered energy homeostasis may be adversely affecting reproductive efforts, as impaired reproduction has been observed in other studies investigating polycyclic aromatic hydrocarbons.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.026
      Issue No: Vol. 199 (2018)
       
  • Part A: Temporal and dose-dependent transcriptional responses in the liver
           of fathead minnows following short term exposure to the polycyclic
           aromatic hydrocarbon phenanthrene
    • Authors: Jennifer R. Loughery; Karen A. Kidd; Angella Mercer; Christopher J. Martyniuk
      Pages: 90 - 102
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Jennifer R. Loughery, Karen A. Kidd, Angella Mercer, Christopher J. Martyniuk
      Phenanthrene is a low molecular weight polycyclic aromatic hydrocarbon (PAH) that is composed of three fused benzene rings. PAHs are formed naturally through incomplete combustion of organic materials, and are environmental contaminants due to anthropogenic activities (e.g. oil extraction and refining, industrial and municipal effluents, fossil fuel burning). Fish exposed to PAHs such as phenanthrene have been reported to exhibit altered reproductive axis endpoints, however the mechanisms that underlie these responses are not fully characterized. To better understand effects at the mechanistic level, we applied transcriptomics to identify molecular pathways altered after acute exposure to phenanthrene on both a dose and temporal scale. Female fathead minnow (Pimephales promelas) were exposed to an average measured concentration of either 0, 29.8, 389 or 943 μg phenanthrene/L for 24, 48, and 72 h in a static-renewal bioassay. Ovaries were assessed for oocyte distribution as well as in vitro 17β-estradiol production and gene expression for transcripts related to steroidogenesis and estrogen signalling. In addition, the liver transcriptome was measured as this tissue is the primary source of the egg yolk precursor protein vitellogenin. Exposure to 29.8 μg phenanthrene/L increased proportions of the cortical alveolar stage in the ovaries after 48 h while the proportion of cortical alveolar oocyte were decreased in fish exposed to 943 μg phenanthrene/L for 48 h. Phenanthrene did not affect 17β-estradiol production at any time or dose, and did not affect transcripts associated with hormone synthesis nor signalling pathways. In the liver, the transcriptome showed fewer genes in common across time when compared to those transcripts affected by concentration at a single time point. Cholesterol metabolism was the only pathway perturbed in the liver following all comparisons in both the dose and time course experiments. Our data suggest that transcriptome networks associated with hepatic lipid metabolism are rapidly affected by phenanthrene, and this may indirectly reduce resources available for reproductive efforts.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.027
      Issue No: Vol. 199 (2018)
       
  • Characterization and comparison of transcriptional activities of the
           retinoid X receptors by various organotin compounds in three prosobranch
           gastropods; Thais clavigera, Nucella lapillus and Babylonia japonica
    • Authors: Hiroshi Urushitani; Yoshinao Katsu; Hiroyuki Kagechika; Ana C.A. Sousa; Carlos M. Barroso; Yasuhiko Ohta; Hiroaki Shiraishi; Taisen Iguchi; Toshihiro Horiguchi
      Pages: 103 - 115
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Hiroshi Urushitani, Yoshinao Katsu, Hiroyuki Kagechika, Ana C.A. Sousa, Carlos M. Barroso, Yasuhiko Ohta, Hiroaki Shiraishi, Taisen Iguchi, Toshihiro Horiguchi
      Two cDNAs of RXR were isolated, for the first time, from the ivory shell, Babylonia japonica, and the transcriptional activities were tested in vitro to compare with other gastropod (Thais clavigera and Nucella lapillus) RXR isoforms. The transcriptional activities of all of these RXR isoforms were significantly induced by mammalian RXR agonist, 9-cis retinoic acid (9cRA). The transcriptional activity of T. clavigera RXR-1 was also examined by using 9cRA and 16 organotin compounds, and significant ligand-dependent transactivations were observed by 9cRA and 5 organotins (tributyltin (TBT), tetrabutyltin (TeBT), tripropyltin (TPrT), tricyclohexyltin (TcHT) and triphenyltin (TPhT)). These 5 organotins also induced significant transcriptional activities in N. lapillus and B. japonica RXR isoforms. These 4 organotins, except for TeBT, have been reported to promote the development of imposex after a month of a single injection each, using female T. clavigera. To investigate the function of gastropod RXR isoforms, the effects of mammalian specific pan-agonist, PA024, and pan-antagonist, HX531, were examined, and significant induction of transcriptional activity by PA024 was demonstrated in these gastropod RXR isoforms. The additions of HX531 significantly suppressed the transcriptional activities of these gastropod RXR isoforms by 9cRA and 5 organotins. Using the mammalian two retinoic acid response elements, the transcriptional activities by 2 agonists, 9cRA and PA024, were different among the RXR isoforms of each gastropod species. With retinoid X response element (RXRE), transcriptional activities of TcRXR-1, BjRXR-1, and NlRXRa were significantly higher than those of TcRXR-2, BjRXR-2, and NlRXRb. Transcriptional activities of TcRXR-2, BjRXR-2, and NlRXRb, however, were significantly higher than those of TcRXR-1, BjRXR-1, and NlRXRa with thyroid hormone response element, TREpal. Thus, induction of imposex in prosobranch gastropods is strongly suggested to be triggered by 9cRA and certain organotins, such as TBT and TPhT through the activation of RXRs. These gastropod RXRs might control the different gene transcription by forming homo- or heterodimer complex with their own isoforms. These findings will contribute to our understanding of the fundamentals of the endocrine system in molluscs, particularly on RXR signaling pathway.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.029
      Issue No: Vol. 199 (2018)
       
  • Microcystin-leucine arginine mediates apoptosis and engulfment of Leydig
           cell by testicular macrophages resulting in reduced serum testosterone
           levels
    • Authors: Yabing Chen; Jing Wang; Xiang Chen; Dongmei Li; Xiaodong Han
      Pages: 116 - 126
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Yabing Chen, Jing Wang, Xiang Chen, Dongmei Li, Xiaodong Han
      Microcystin-leucine arginine (MC-LR) causes decline of serum testosterone levels resulting in impaired spermatogenesis; however, the underlying molecular mechanisms are not fully understood. In this study, we aimed to investigate the effects of MC-LR exposure on the number of Leydig cells (LCs) in testis. Following chronic low dose exposure to MC-LR, the number of LCs was markedly decreased while macrophages were significantly increased. Then, we established a co-culture system to study the interaction between macrophages and LCs in the presence of MC-LR. No significant apoptosis of LCs cultured alone was observed after MC-LR (< 5 000 nM) treatment; however, apoptosis was robustly increased when LCs were co-cultured with macrophages in the presence of MC-LR. Further studies identified that MC-LR could stimulate macrophage to produce TNF-α, and secreted TNF-α induced LC apoptosis by binding to the tumor necrosis factor receptor 1 (TNFR1) on the LCs and thus activating reactive oxygen species (ROS)-p38MAPK signaling pathway. Furthermore, we also examined increased expression of Axl receptor and growth arrest-specific 6 (Gas6) in macrophages after MC-LR treatment. GAS6 mediates phagocytosis of apoptotic LCs by binding to the Axl receptor on macrophages and phosphatidylserine (PtdSer) on apoptotic LCs. Together, these results suggested that reduced serum testosterone levels may be associated with decrease of LCs as a result of LC apoptosis and phagocytosis by immune cells in MC-LR-treated mice.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.018
      Issue No: Vol. 199 (2018)
       
  • Oyster transcriptome response to Alexandrium exposure is related to
           saxitoxin load and characterized by disrupted digestion, energy balance,
           and calcium and sodium signaling
    • Authors: Audrey M. Mat; Christophe Klopp; Laura Payton; Céline Jeziorski; Morgane Chalopin; Zouher Amzil; Damien Tran; Gary H. Wikfors; Hélène Hégaret; Philippe Soudant; Arnaud Huvet; Caroline Fabioux
      Pages: 127 - 137
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Audrey M. Mat, Christophe Klopp, Laura Payton, Céline Jeziorski, Morgane Chalopin, Zouher Amzil, Damien Tran, Gary H. Wikfors, Hélène Hégaret, Philippe Soudant, Arnaud Huvet, Caroline Fabioux
      Harmful Algal Blooms are worldwide occurrences that can cause poisoning in human seafood consumers as well as mortality and sublethal effets in wildlife, propagating economic losses. One of the most widespread toxigenic microalgal taxa is the dinoflagellate Genus Alexandrium, that includes species producing neurotoxins referred to as PST (Paralytic Shellfish Toxins). Blooms cause shellfish harvest restrictions to protect human consumers from accumulated toxins. Large inter-individual variability in toxin load within an exposed bivalve population complicates monitoring of shellfish toxicity for ecology and human health regulation. To decipher the physiological pathways involved in the bivalve response to PST, we explored the whole transcriptome of the digestive gland of the Pacific oyster Crassostrea gigas fed experimentally with a toxic Alexandrium minutum culture. The largest differences in transcript abundance were between oysters with contrasting toxin loads (1098 transcripts), rather than between exposed and non-exposed oysters (16 transcripts), emphasizing the importance of toxin load in oyster response to toxic dinoflagellates. Additionally, penalized regressions, innovative in this field, modeled accurately toxin load based upon only 70 transcripts. Transcriptomic differences between oysters with contrasting PST burdens revealed a limited suite of metabolic pathways affected, including ion channels, neuromuscular communication, and digestion, all of which are interconnected and linked to sodium and calcium exchanges. Carbohydrate metabolism, unconsidered previously in studies of harmful algal effects on shellfish, was also highlighted, suggesting energy challenge in oysters with high toxin loads. Associations between toxin load, genotype, and mRNA levels were revealed that open new doors for genetic studies identifying genetically-based low toxin accumulation.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.030
      Issue No: Vol. 199 (2018)
       
  • Transcriptomics provides mechanistic indicators of mixture toxicology for
           
    • Authors: Kurt A. Gust; Guilherme R. Lotufo; Jacob K. Stanley; Mitchell S. Wilbanks; Pornsawan Chappell; Natalie D. Barker
      Pages: 138 - 151
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Kurt A. Gust, Guilherme R. Lotufo, Jacob K. Stanley, Mitchell S. Wilbanks, Pornsawan Chappell, Natalie D. Barker
      Within the US military, new insensitive munitions (IMs) are rapidly replacing conventional munitions improving safety from unintended detonation. Toxicity data for IM chemicals are expanding rapidly, however IM constituents are typically deployed in mixture formulations, and very little is known about their mixture toxicology. In the present study we sought to characterize the mixture effects and toxicology of the two predominant IM formulations IMX-101 and IMX-104 in acute (48 h) larval fathead minnow (Pimephales promelas) exposures. IMX-101 consists of a mixture of 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ) while IMX-104 is composed of DNAN, NTO, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). DNAN was the most potent constituent in IMX-101 eliciting an LC50 of 36.1 mg/L, whereas NTO and NQ did not elicit significant mortality in exposures up to 1040 and 2640 mg/L, respectively. Toxic unit calculations indicated that IMX-101 elicited toxicity representative of the component concentration of DNAN within the mixture. Toxicogenomic responses for the individual constituents of IMX-101 indicated unique transcriptional expression and functional responses characteristic of: oxidative stress, impaired energy metabolism, tissue damage and inflammatory responses in DNAN exposures; impaired steroid biosynthesis and developmental cell-signaling in NQ exposures; and altered mitogen-activated protein kinase signaling in NTO exposures. Transcriptional responses to the IMX-101 mixture were driven by the effects of DNAN where expression and functional responses were nearly identical comparing DNAN alone versus the fractional equivalent of DNAN within IMX-101. Given that each individual constituent of the IMX-101 mixture elicited unique functional responses, and NTO and NQ did not interact with DNAN within the IMX-101 mixture exposure, the overall toxicity and toxicogenomic responses within acute exposures to the IMX-101 formulation are indicative of “independent” mixture toxicology. Alternatively, in the IMX-104 exposure both DNAN and RDX were each present at concentrations sufficient to elicit lethality (RDX LC50 = 28.9 mg/L). Toxic-unit calculations for IMX-104 mixture formulation exposures indicated slight synergistic toxicity (ΣTU LC50 = 0.82, 95% confidence interval = 0.73–0.90). Unique functional responses relative to DNAN were observed in the IMX-104 exposure including responses characteristic of RDX exposure. Based on previous transcriptomics responses to acute RDX exposures in fathead minnow larvae, we hypothesize that the potentially synergistic responses within the IMX-104 mixture are related to interactive effects of each DNAN and RDX on oxidative stress mitigation pathways.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.019
      Issue No: Vol. 199 (2018)
       
  • NmtA, a novel metallothionein of Anabaena sp. strain PCC 7120 imparts
           protection against cadmium stress but not oxidative stress
    • Authors: Divya T V; Pallavi Chandwadkar; Celin Acharya
      Pages: 152 - 161
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Divya T V, Pallavi Chandwadkar, Celin Acharya
      Metallothioneins (MTs) are low molecular weight, sulfhydryl-containing, cysteine-rich, metal-binding proteins. Eukaryotes have multiple metallothionein genes; however, there is dearth of reports on prokaryotic metallothioneins. Bacterial MTs with SmtA from Synechococcus PCC 7942 as prototype have been studied in the context of cadmium detoxification. In this study, a smtA related ORF, namely nmtA, was identified in the heterocystous, nitrogen-fixing cyanobacterium, Anabaena PCC 7120. A recombinant N-terminal histidine-tagged Anabaena NmtA protein was overexpressed in Escherichia coli and purified. The protein was identified by peptide mass fingerprinting using MALDI-TOF Mass Spectrometry as putative metallothionein of Anabaena PCC 7120 with a calculated mass of ∼6.1 kDa. While the native metallated NmtA exhibited resistance against proteolysis, metal free apo-NmtA resulting from acid and dithiothreitol (DTT) treatment could be digested by proteinase K revealing a metal dependent proteolytic protection of NmtA. Expression of nmtA in Anabaena PCC 7120 was induced evidently by cadmium, zinc and copper but not by uranium or hydrogen peroxide. Recombinant Anabaena PCC 7120 overexpressing NmtA protein revealed superior cadmium tolerance but showed limited influence against oxidative stress tolerance as compared with the strain carrying vector alone. In contrast, a mutant of Synechococcus PCC 7942 deficient in MT locus was found to be highly susceptible to H2O2 indicating a likely involvement of cyanobacterial MT in protection against oxidative damage. Overall, the study improved our understanding of metal tolerance mechanisms in Anabaena PCC 7120 by demonstrating a key role of NmtA in cadmium tolerance.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.035
      Issue No: Vol. 199 (2018)
       
  • High-throughput assessment of oxidative respiration in fish embryos:
           Advancing adverse outcome pathways for mitochondrial dysfunction
    • Authors: Christopher L. Souders; Xuefang Liang; Xiaohong Wang; Naomi Ector; Yuan H. Zhao; Christopher J. Martyniuk
      Pages: 162 - 173
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Christopher L. Souders, Xuefang Liang, Xiaohong Wang, Naomi Ector, Yuan H. Zhao, Christopher J. Martyniuk
      Mitochondrial dysfunction is a prevalent molecular event that can result in multiple adverse outcomes. Recently, a novel high throughput method to assess metabolic capacity in fish embryos following exposure to chemicals has been adapted for environmental toxicology. Assessments of oxygen consumption rates using the Seahorse XF(e) 24/96 Extracellular Flux Analyzer (Agilent Technologies) can be used to garner insight into toxicant effects at early stages of development. Here we synthesize the current state of the science using high throughput metabolic profiling in zebrafish embryos, and present considerations for those wishing to adopt high throughput methods for mitochondrial bioenergetics into their research. Chemicals that have been investigated in zebrafish using this metabolic platform include herbicides (e.g. paraquat, diquat), industrial compounds (e.g. benzo-[a]-pyrene, tributyltin), natural products (e.g. quercetin), and anti-bacterial chemicals (i.e. triclosan). Some of these chemicals inhibit mitochondrial endpoints in the μM-mM range, and reduce basal respiration, maximum respiration, and spare capacity. We present a theoretical framework for how one can use mitochondrial performance data in zebrafish to categorize chemicals of concern and prioritize mitochondrial toxicants. Noteworthy is that our studies demonstrate that there can be considerable variation in basal respiration of untreated zebrafish embryos due to clutch-specific effects as well as individual variability, and basal oxygen consumption rates (OCR) can vary on average between 100 and 300 pmol/min/embryo. We also compare OCR between chorionated and dechorionated embryos, as both models are employed to test chemicals. After 24 h, dechorionated embryos remain responsive to mitochondrial toxicants, although they show a blunted response to the uncoupling agent carbonylcyanide-4-trifluoromethoxyphenylhydrazone (FCCP); dechorionated embryos are therefore a viable option for investigations into mitochondrial bioenergetics. We present an adverse outcome pathway framework that incorporates endpoints related to mitochondrial bioenergetics. High throughput bioenergetics assays conducted using whole embryos are expected to support adverse outcome pathways for mitochondrial dysfunction.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.031
      Issue No: Vol. 199 (2018)
       
  • Transcriptional effects of phospholipid fatty acid profile on rainbow
           trout liver cells exposed to methylmercury
    • Authors: Aline Ferain; Chloé Bonnineau; Ineke Neefs; Krishna Das; Yvan Larondelle; Jean-François Rees; Cathy Debier; Benjamin Lemaire
      Pages: 174 - 187
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Aline Ferain, Chloé Bonnineau, Ineke Neefs, Krishna Das, Yvan Larondelle, Jean-François Rees, Cathy Debier, Benjamin Lemaire
      Lipids, and their constitutive fatty acids, are key nutrients for fish health as they provide energy, maintain cell structure, are precursors of signalling molecules and act as nuclear receptor ligands. These specific roles may be of crucial importance in a context of exposure to pollutants. We recently showed that the fatty acid profile of rainbow trout liver cell phospholipids modulates sensitivity to an acute methylmercury challenge. In order to investigate mechanisms of effects, we herein tested whether specific polyunsaturated fatty acids (PUFAs) may protect cells from methylmercury through decreasing intracellular mercury accumulation and/or enhancing cellular defences (e.g. via modulation of gene expression patterns). We also investigated the inverse relationship and assessed the impact of methylmercury on cellular fatty acid metabolism. To do so, the fatty acid composition of rainbow trout liver cell phospholipids was first modified by incubating them in a medium enriched in a specific PUFA from either the n-3 family (alpha-linolenic acid, ALA; eicosapentaenoic acid, EPA) or the n-6 family (linoleic acid, LA; arachidonic acid, AA). Cells were then exposed to methylmercury (0.15 or 0.50 μM) for 24 h and sampled thereafter for assessing phospholipid fatty acid profile, intracellular total mercury burden, and expression pattern of genes involved in fatty acid metabolism, synthesis of PUFA-derived signalling molecules and stress response. We observed that cells incorporated the given PUFA and some biotransformation products in their phospholipids. Methylmercury had few impacts on this cellular phospholipid composition. None of the PUFA enrichments affected the cellular mercury burden, suggesting that the previously observed cytoprotection conferred by ALA and EPA was not linked to a global decrease in cellular accumulation of mercury. Fatty acid enrichments and methylmercury exposure both modulated gene expression patterns. Genes involved in the synthesis of PUFA-derived signalling molecules, in stress response and the orphan cytochrome P450 20A1 were identified as possible sites of interaction between fatty acids and methylmercury in rainbow trout liver cells.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.025
      Issue No: Vol. 199 (2018)
       
  • Bioactive extracellular compounds produced by the dinoflagellate
           Alexandrium minutum are highly detrimental for oysters
    • Authors: J. Castrec; P. Soudant; L. Payton; D. Tran; P. Miner; C. Lambert; N. Le Goïc; A. Huvet; V. Quillien; F. Boullot; Z. Amzil; H. Hégaret; C. Fabioux
      Pages: 188 - 198
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): J. Castrec, P. Soudant, L. Payton, D. Tran, P. Miner, C. Lambert, N. Le Goïc, A. Huvet, V. Quillien, F. Boullot, Z. Amzil, H. Hégaret, C. Fabioux
      Blooms of the dinoflagellate Alexandrium spp., known as producers of paralytic shellfish toxins (PSTs), are regularly detected on the French coastline. PSTs accumulate into harvested shellfish species, such as the Pacific oyster Crassostrea gigas, and can cause strong disorders to consumers at high doses. The impacts of Alexandrium minutum on C. gigas have often been attributed to its production of PSTs without testing separately the effects of the bioactive extracellular compounds (BECs) with allelopathic, hemolytic, cytotoxic or ichthyotoxic properties, which can also be produced by these algae. The BECs, still uncharacterized, are excreted within the environment thereby impacting not only phytoplankton, zooplankton but also marine invertebrates and fishes, without implicating any PST. The aim of this work was to compare the effects of three strains of A. minutum producing either only PSTs, only BECs, or both PSTs and BECs, on the oyster C. gigas. Behavioral and physiological responses of oysters exposed during 4 days were monitored and showed contrasted behavioral and physiological responses in oysters supposedly depending on produced bioactive substances. The non-PST extracellular-compound-producing strain primarily strongly modified valve-activity behavior of C. gigas and induced hemocyte mobilization within the gills, whereas the PST-producing strain caused inflammatory responses within the digestive gland and disrupted the daily biological rhythm of valve activity behavior. BECs may therefore have a significant harmful effect on the gills, which is one of the first organ in contact with the extracellular substances released in the water by A. minutum. Conversely, the PSTs impact the digestive gland, where they are released and mainly accumulated, after degradation of algal cells during digestion process of bivalves. This study provides a better understanding of the toxicity of A. minutum on oyster and highlights the significant role of BECs in this toxicity calling for further chemical characterization of these substances.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.034
      Issue No: Vol. 199 (2018)
       
  • Effects of multi-walled carbon nanotube materials on Ruditapes
           philippinarum under climate change: The case of salinity shifts
    • Authors: Lucia De Marchi; Victor Neto; Carlo Pretti; Etelvina Figueira; Federica Chiellini; Andrea Morelli; Amadeu M.V.M. Soares; Rosa Freitas
      Pages: 199 - 211
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Lucia De Marchi, Victor Neto, Carlo Pretti, Etelvina Figueira, Federica Chiellini, Andrea Morelli, Amadeu M.V.M. Soares, Rosa Freitas
      The toxicity of carbon nanotubes (CNTs) is closely related to their physico-chemical characteristics as well as the physico-chemical parameters of the media where CNTs are dispersed. In a climate change scenario, changes in seawater salinity are becoming a topic of concern particularly in estuarine and coastal areas. Nevertheless, to our knowledge no information is available on how salinity shifts may alter the sensitivity (in terms of biochemical responses) of bivalves when exposed to different CNTs. For this reason, a laboratory experiment was performed exposing the Manila clam Ruditapes philippinarum, one of the most dominant bivalves of the estuarine and coastal lagoon environments, for 28 days to unfunctionalized multi-walled carbon nanotube MWCNTs (Nf-MWCNTs) and carboxylated MWCNTs (f-MWCNTs), maintained at control salinity (28) and low salinity 21. Concentration-dependent toxicity was demonstrated in individuals exposed to both MWCNT materials and under both salinities, generating alterations of energy reserves and metabolism, oxidative status and neurotoxicity compared to non-contaminated clams. Moreover, our results showed greater toxic impacts induced in clams exposed to f-MWCNTs compared to Nf-MWCNTs. In the present study it was also demonstrated how salinity shifts altered the toxicity of both MWCNT materials as well as the sensitivity of R. philippinarum exposed to these contaminates in terms of clam metabolism, oxidative status and neurotoxicity.
      Graphical abstract image

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.04.001
      Issue No: Vol. 199 (2018)
       
  • Effect of titanium dioxide nanoparticles on the bioavailability and
           neurotoxicity of cypermethrin in zebrafish larvae
    • Authors: Meng Li; Qiong Wu; Qiangwei Wang; Dandan Xiang; Guonian Zhu
      Pages: 212 - 219
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Meng Li, Qiong Wu, Qiangwei Wang, Dandan Xiang, Guonian Zhu
      In aquatic environment, the presence of nanoparticles (NPs) has been reported to modify the bioavailability and toxicity of the organic toxicants. Nevertheless, the combined toxicity of NPs and the pesticides that were used world-widely still remains unclear. Cypermethrin (CYP), a synthetic pyrethroid insecticide, is commonly used for controlling agricultural and indoor pests. Therefore, the effects of titanium dioxide NPs (nTiO2) on CYP bioconcentration and its effects on the neuronal development in zebrafish were investigated in our study. Zebrafish embryos (2- hour-post-fertilization, hpf) were exposed to CYP (0, 0.4, 2 and 10 μg/L) alone or co-exposed with nTiO2 (1 mg/L) until 120-hpf. nTiO2 is taken up by zebrafish larvae and also it can adsorb CYP. The zebrafish body burdens of CYP was observed and CYP uptake was increased by nTiO2, indicating that the nTiO2 could accelerate the bioaccumulation of CYP in larvae. Co-exposure of nTiO2 and CYP induced the generation of reactive oxygen species. Exposure to CYP alone significantly decreased the mRNA expression of genes, including glial fibrillary acidic protein (gfap), α1-tubulin, myelin basic protein (mbp) and growth associated protein (gap-43). Besides, reductions of serotonin, dopamine and GABA concentrations were observed in zebrafish and the larval locomotion was significantly decreased in response to the lower level of the neurotransmitters. Moreover, co-exposure of nTiO2 and CYP caused further significantly decreased in the locomotion activity, and enhanced the down-regulation of the mRNA expression of specific genes and the neurotransmitters levels. The results demonstrated that nTiO2 increased CYP accumulation and enhanced CYP-induced developmental neurotoxicity in zebrafish.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.022
      Issue No: Vol. 199 (2018)
       
  • The physiological effects of oil, dispersant and dispersed oil on the bay
           mussel, Mytilus trossulus, in Arctic/Subarctic conditions
    • Authors: Katrina L. Counihan
      Pages: 220 - 231
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Katrina L. Counihan
      Increasing oil development around Alaska and other Arctic regions elevates the risk for another oil spill. Dispersants are used to mitigate the impact of an oil spill by accelerating natural degradation processes, but the reduced hydrophobicity of dispersed oil may increase its bioavailability to marine organisms. There is limited research on the effect of dispersed oil on cold water species and ecosystems. Therefore, spiked exposure tests were conducted with bay mussels (Mytilus trossulus) in seawater with non-dispersed oil, Corexit 9500 and oil dispersed with different concentrations of Corexit 9500. After three weeks of exposure, acute and chronic physiological impacts were determined. The majority of physiological responses occurred during the first seven days of exposure, with mussels exhibiting significant cytochrome P450 activity, superoxide dismutase activity and heat shock protein levels. Mussels exposed to non-dispersed oil also experienced immune suppression, reduced transcription and higher levels of mortality. After 21 days, mussels in all treatments exhibited evidence of genetic damage, tissue loss and a continued stress response. Bay mussels are useful as indicators of ecosystem health and recovery, and this study was an important step in understanding how non-dispersed oil, dispersant and dispersed oil affect the physiology of this sentinel species in Arctic/subarctic conditions.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.04.002
      Issue No: Vol. 199 (2018)
       
  • Metabolite profiles of striped marsh frog (Limnodynastes peronii) larvae
           exposed to the anti-androgenic fungicides vinclozolin and propiconazole
           are consistent with altered steroidogenesis and oxidative stress
    • Authors: Steven D. Melvin; Frederic D.L. Leusch; Anthony R. Carroll
      Pages: 232 - 239
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Steven D. Melvin, Frederic D.L. Leusch, Anthony R. Carroll
      Amphibians use wetlands in urban and agricultural landscapes for breeding, growth and development. Fungicides and other pesticides used in these areas have therefore been identified as potential threats that could contribute towards amphibian population declines. However, relatively little is known about how such chemicals influence sensitive early life-stages or how short episodic exposures influence sub-lethal physiological and metabolic pathways. The present study applied untargeted metabolomics to evaluate effects in early post-hatch amphibian larvae exposed to the anti-androgenic fungicides vinclozolin and propiconazole. Recently hatched (Gosner developmental stage 25) striped marsh frog (Limnodynastes peronii) larvae were exposed for 96 h to vinclozolin at 17.5, 174.8 and 1748.6 nM and propiconazole at 5.8, 58.4 and 584.4 nM. Nuclear Magnetic Resonance (NMR) spectroscopy was performed on polar metabolites obtained from whole-body extracts. Both fungicides altered metabolite profiles compared to control animals at all concentrations tested, and there were notable differences between the two chemicals. Overall responses were consistent with altered steroidogenesis and/or cholesterol metabolism, with inconsistent responses between the two fungicides likely reflecting minor differences in the mechanisms of action of these chemicals. Broad down-regulation of the tricarboxylic acid (TCA) cycle was also observed and is indicative of oxidative stress. Interestingly, formic acid was significantly increased in larvae exposed to vinclozolin but not propiconazole, suggesting this metabolite may serve as a useful biomarker of exposure to androgen-receptor binding anti-androgenic contaminants. This study demonstrates the power of untargeted metabolomics for distinguishing between similarly acting, but distinct, pollutants and for unraveling non-endocrine responses resulting from exposure to known endocrine active contaminants.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.04.004
      Issue No: Vol. 199 (2018)
       
  • Effects of multiple life stage exposure to the fungicide prochloraz in
           Xenopus laevis: Manifestations of antiandrogenic and other modes of
           toxicity
    • Authors: Jonathan T. Haselman; Patricia A. Kosian; Joseph J. Korte; Allen W. Olmstead; Sigmund J. Degitz
      Pages: 240 - 251
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Jonathan T. Haselman, Patricia A. Kosian, Joseph J. Korte, Allen W. Olmstead, Sigmund J. Degitz
      The Larval Amphibian Growth and Development Assay (LAGDA) is an internationally harmonized testing guideline for evaluating effects of chronic chemical exposure in amphibians. In order to evaluate the effects of chronic exposure to an antiandrogenic chemical in an amphibian model, prochloraz was tested using a variation of the LAGDA design. Exposure was initiated with <1d post-fertilization embryos at nominal concentrations of 0, 6.7, 20, 60 and 180 μg/L (0, 18, 53, 159, 478 nM) and continued in flow-through conditions until two months following the median time that controls completed metamorphosis. Growth, developmental rate, circulating thyroid hormone and thyroid gland histopathology were evaluated in a subsample at completion of metamorphosis. There were no effects on growth or development at this stage, but circulating thyroid hormone was elevated in the 20, 60 and 180 μg/L treatments and minimal to mild thyroid follicular cell hypertrophy was observed histologically in the 180 μg/L treatment. Growth, overt toxicity, and reproductive development were evaluated at test termination. There were no effects on growth in either gender, but livers and kidneys exhibited treatment-related pathologies consistent with organ toxicity related to metabolism and presumably impaired excretion of prochloraz metabolites. Histological assessments of female ovaries resulted in minimal pathologies only in the 180 μg/L treatment while male testes exhibited numerous treatment-related pathologies that are consistent with previously reported antiandrogenic effects of prochloraz in other species. The most severe testis pathologies occurred in the 180 μg/L treatment; however, incidences of treatment-related pathologies occurred in all prochloraz treatments. Müllerian duct regression in males was inhibited by prochloraz exposure while Müllerian duct maturation in females was accelerated, characteristic of a feminizing effect. Gene expression levels of potential biomarkers of testis function were also measured. Relative abundance of cyp17a1 transcripts was generally unaffected by prochloraz exposure whereas the Insl3 orthologue, rflcii, was elevated by 3 and >5-fold in the 60 and 180 μg/L treatments, respectively, indicating impaired Leydig cell maturation and testosterone signaling. Overall, prochloraz exposure caused effects characteristic of an antiandrogenic mode of action, which is consistent with previously reported results in other species and supports the utility of the LAGDA design for chemical testing.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.013
      Issue No: Vol. 199 (2018)
       
  • Effects of chronic exposure to cadmium and temperature, alone or combined,
           on the threespine stickleback (Gasterosteus aculeatus): Interest of
           digestive enzymes as biomarkers
    • Authors: Younes Mohamed Ismail Hani; Cyril Turies; Olivier Palluel; Laurence Delahaut; Véronique Gaillet; Anne Bado-nilles; Jean-Marc Porcher; Alain Geffard; Odile Dedourge-geffard
      Pages: 252 - 262
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Younes Mohamed Ismail Hani, Cyril Turies, Olivier Palluel, Laurence Delahaut, Véronique Gaillet, Anne Bado-nilles, Jean-Marc Porcher, Alain Geffard, Odile Dedourge-geffard
      The development of predictive, sensitive and reliable biomarkers is of crucial importance for aquatic biomonitoring to assess the effects of chemical substances on aquatic organisms, especially when it comes to combined effects with other stressors (e.g. temperature). The first purpose of the present study was to evaluate the single and combined effects of 90 days of exposure to an environmental cadmium concentration (0.5 μg L−1) and two water temperatures (16 and 21 °C) on different parameters. These parameters are involved in (i) the antioxidant system (superoxide dismutase activity –SOD– and total glutathione levels –GSH–), (ii) the energy metabolism, i.e. energy reserves (glycogen, lipids, proteins) and digestive enzymes (trypsin, amylase, intestinal alkaline phosphatase –IAP–), and (iii) biometric parameters (weight, length, Fulton’s condition factor, and the gonadosomatic index –GSI–) of threespine stickleback (Gasterosteus aculeatus). The second purpose was to determine the interest of the three digestive enzymes as biomarkers in comparison with the other parameters. The higher temperature (21 °C) impacted the anti-oxidant and energy reserve parameters. In liver, GSH levels increased on day 60, while SOD decreased on days 15 and 90, with a significant decrease of protein and lipid energy reserves on day 90. In muscle, the higher temperature decreased SOD activity only on day 90. G. aculeatus biometric parameters were also impacted by the higher temperature, which limited stickleback growth after 90 days of exposure. In female sticklebacks, the GSI peaked on day 60 and decreased sharply on day 90, while the highest values were reached at day 90 in the control groups, suggesting impaired reproduction in sticklebacks raised at 21 °C. These results suggest that 21 °C is an upper-limit temperature for long-term physiological processes in sticklebacks. In contrast, very low-concentration cadmium exposure had no effect on classical biomarkers (energy reserves, antioxidant parameters, biometric parameters). However, digestive enzymes showed an interesting sensitivity to cadmium, which was emphasized by high temperature. The activity of the three digestive enzymes decreased significantly on day 90 when sticklebacks were exposed to cadmium alone, while the decrease was stronger and was recorded earlier (from day 15) when they were exposed to the cadmium-temperature combination. Compared to conventional measurements, digestive enzymes responded rapidly. This could be an important advantage for them to be used as early warning tools to reflect the health status of organisms, particularly for trypsin and IAP activities.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.04.006
      Issue No: Vol. 199 (2018)
       
  • In vitro bioassays reveal that additives are significant contributors to
           the toxicity of commercial household pesticides
    • Authors: Jason P. van de Merwe; Peta A. Neale; Steven D. Melvin; Frederic D.L. Leusch
      Pages: 263 - 268
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Jason P. van de Merwe, Peta A. Neale, Steven D. Melvin, Frederic D.L. Leusch
      Pesticides commonly used around households can contain additives of unknown concentrations and toxicity. Given the likelihood of these chemicals washing into urban waterways, it is important to understand the effects that these additives may have on aquatic organisms. The aim of this study was to compare the toxicity of commercially available household pesticides to that of the active ingredient(s) alone. The toxicity of five household pesticides (three herbicides and two insecticides) was investigated using a bacterial cytotoxicity bioassay and an algal photosynthesis bioassay. The commercial products were up to an order of magnitude more toxic than the active ingredient(s) alone. In addition, two commercial products with the same listed active ingredients in the same ratio had a 600× difference in potency. These results clearly demonstrate that additives in commercial formulations are significant contributors to the toxicity of household pesticides. The toxicity of pesticides in aquatic systems is therefore likely underestimated by conventional chemical monitoring and risk assessment when only the active ingredients are considered. Regulators and customers should require more clarity from pesticide manufacturers about the nature and concentrations of not only the active ingredients, but also additives used in commercial formulations. In addition, monitoring programmes and chemical risk assessments schemes should develop a structured approach to assessing the toxic effects of commercial formulations, including additives, rather than simply those of the listed active ingredients.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.033
      Issue No: Vol. 199 (2018)
       
  • Gemfibrozil and carbamazepine decrease steroid production in zebrafish
           testes (Danio rerio)
    • Authors: Shamaila Fraz; Abigail H. Lee; Joanna Y. Wilson
      Pages: 1 - 9
      Abstract: Publication date: Available online 10 February 2018
      Source:Aquatic Toxicology
      Author(s): Shamaila Fraz, Abigail H. Lee, Joanna Y. Wilson
      Gemfibrozil (GEM) and carbamazepine (CBZ) are two environmentally relevant pharmaceuticals and chronic exposure of fish to these compounds has decreased androgen levels and fish reproduction in laboratory studies. The main focus of this study was to examine the effects of GEM and CBZ on testicular steroid production, using zebrafish as a model species. Chronic water borne exposures of adult zebrafish to 10 μg/L of GEM and CBZ were conducted and the dosing was confirmed by chemical analysis of water as 17.5 ± 1.78 and 11.2 ± 1.08 μg/L respectively. A 67 day exposure led to reduced reproductive output and lowered whole body, plasma, and testicular 11-ketotestosterone (11-KT). Testicular production of 11-KT was examined post exposure (42 days) using ex vivo cultures to determine basal and stimulated steroid production. The goal was to ascertain the step impaired in the steroidogenic pathway by each compound. Ex vivo 11-KT production in testes from males chronically exposed to GEM and CBZ was lower than that from unexposed males. Although hCG, 25-OH cholesterol, and pregnenolone stimulation increased 11-KT production in all treatment groups over basal levels, hCG stimulated 11-KT production remained significantly less in testes from exposed males compared to controls. 25-OH cholesterol and pregnenolone stimulated 11-KT production was similar between GEM and control groups but the CBZ group had lower 11-KT production than controls with both stimulants. We therefore propose that chronic GEM and CBZ exposure can reduce production of 11-KT in testes through direct effects independent of mediation through HPG axis. The biochemical processes for steroid production appear un-impacted by GEM exposure; while CBZ exposure may influence steroidogenic enzyme expression or function.

      PubDate: 2018-02-14T08:53:33Z
      DOI: 10.1016/j.aquatox.2018.02.006
      Issue No: Vol. 198 (2018)
       
  • Effects of single and combined exposure of pharmaceutical drugs
           (carbamazepine and cetirizine) and a metal (cadmium) on the biochemical
           responses of R. philippinarum
    • Authors: Ângela Almeida; Vânia Calisto; Valdemar I. Esteves; Rudolf J. Schneider; Amadeu M.V.M. Soares; Etelvina Figueira; Rosa Freitas
      Pages: 10 - 19
      Abstract: Publication date: Available online 19 February 2018
      Source:Aquatic Toxicology
      Author(s): Ângela Almeida, Vânia Calisto, Valdemar I. Esteves, Rudolf J. Schneider, Amadeu M.V.M. Soares, Etelvina Figueira, Rosa Freitas
      In the aquatic environment, organisms are exposed to complex mixtures of contaminants which may alter the toxicity profile of each compound, compared to its toxicity alone. Pharmaceutical drugs (e.g. carbamazepine (CBZ) and cetirizine (CTZ)), and metals (e.g. cadmium (Cd)), are among those contaminants that co-occur in the environment. However, most studies concerning their toxicity towards aquatic species are based on single exposure experiments. Thus, the present study aimed to evaluate single and combined effects of Cd and CBZ or CTZ (single conditions: Cd, CTZ, CBZ; combined conditions: CTZ + Cd, CBZ + Cd) on biomarkers related to oxidative stress and energy metabolism in the edible clam Ruditapes philippinarum, by exposing the organisms for 28 days to environmentally relevant concentrations of these contaminants. The biomarkers studied were: i) the electron transport system activity, protein and glycogen content (indicators of organisms’ metabolic status); ii) lipid peroxidation and the ratio between reduced and oxidized glutathione (indicators of oxidative stress); iii) superoxide dismutase and catalase activities (indicators of antioxidant defence) and iv) activities of glutathione S-transferases (indicator of biotransformation capacity). Results obtained showed that the uptake of Cd and CBZ was not affected by the combined presence of the contaminants. However, for CTZ, the uptake was higher in the presence than in the absence of Cd. Concerning toxicity data in general, the combined exposures (CTZ + Cd, CBZ + Cd) had lower biological effects than the contaminants alone. Nevertheless, our data showed that despite the low concentrations tested, they were enough to exert biological effects that differed between single and combined treatments, evidencing the need to conduct more co-exposure studies to increase the environmental relevance of the gathered data.

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.011
      Issue No: Vol. 198 (2018)
       
  • Bioaccumulation and physiological effects of copepods sp. (Eucyclop sp.)
           fed Chlorella ellipsoides exposed to titanium dioxide (TiO2) nanoparticles
           and lead (Pb2+)
    • Authors: Moise M. Matouke; Moshood Mustapha
      Pages: 30 - 39
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Moise M. Matouke, Moshood Mustapha
      The demand for manufactured products and the derivatives of nanomaterials and non essential metals continue to increase, and as a consequence their presence in fisheries and aquaculture has therefore become a major concern for the risks to which our environment is exposed. The bioaccumulation profile of binary compounds (Titanium dioxide nanoparticles and lead) and their effects on the feeding behaviour of copepods were assessed in a simplified food chain including, the freshwater alga Chlorella ellipsoides and the cyclopoids copepods sp. Our results indicated that Pb and TiO2 NPs individually and mixed can be transferred from alga to copepods via dietary pathway. The highest bioconcentration factor (748.5) was recorded for Pb in the combined compounds (Pb15 + Ti16.5) μg L−1 and the highest BCF (5.57) recorded for TiO2 NPs was found in TiO2 NPs (16.5) alone. Ingestion and filtration rate decreased significantly (p < 0.05) in all treatments. Analysis of variance (ANOVA) showed that the combination of these metals significantly (p < 0.05) decreased ingestion and filtration rate. In addition, the individual compounds and their combinations significantly (p < 0.05) increased carbohydrate and total lipid content. The antioxidant activities showed significant (p < 0.05) effect of Glutathione peroxidase (GPx), Glutathione reductase (GR), catalase (CAT) however, SOD and MDA were not significant (p > 0.05) in both single and binary treatments. The results demonstrate that the co-exposure of TiO2 NPs and Pb inhibit the ingestion and filtration of microalgae by cyclopoid copepods sp. and also induce increase of carbohydrate, lipid; GPx, GR and CAT due to stress.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.02.013
      Issue No: Vol. 198 (2018)
       
  • Binary effect of titanium dioxide nanoparticles (nTio2) and phosphorus on
           microalgae (Chlorella ‘Ellipsoides Gerneck, 1907)
    • Authors: Moise M Matouke; Dorcas T Elewa; Karimatu Abdullahi
      Pages: 40 - 48
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Moise M Matouke, Dorcas T Elewa, Karimatu Abdullahi
      The wide application of titanium dioxide nanoparticles and phosphorus in the manufacturing of many industrial products mainly used in agricultural sector has resulted in the release of considerable amounts of these compounds into freshwater aquatic ecosystem. These compounds may cause some unexpected effects to aquatic organisms. This study assessed the binary effects of Titanium nanoparticles (nTiO2) and Phosphorus on Chlorella ellipsoides. Toxicological assay test of the compounds nTiO2 (1.25 μM) alone and the combination of Titanium dioxide (1.25 μM) and Phosphorus (16, 32, 80, 160, 240 μM) was assessed, after 96 h exposures, for optical density (OD680), specific growth rate, chlorophyll levels and lipid peroxidation via Malondialdehyde (MDA) activity. Superoxide dismutase (SOD), peroxidase (POD) and glutathione-s-transferase (GST) activities were also measured. Two-way ANOVA showed a significant interaction (P < 0.05) between binary mixture. Co-exposure showed a decreased phosphorus bioconcentration in the microalgae with significant increase (P < 0.05) in chlorophyll a/b and total chlorophyll contents. A significant decrease (P < 0.05) in specific growth rate and optical density were recorded whereas, antioxidant enzymes (MDA, SOD, POD, GST) activities were significantly (P < 0.05) increased. These results showed that the addition of nTiO2 to Phosphorus affected the physiology of microalgae and should be of great concern for freshwater biodiversity.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.02.009
      Issue No: Vol. 198 (2018)
       
  • Toxicity of sediment-bound lufenuron to benthic arthropods in laboratory
           bioassays
    • Authors: T.C.M. Brock; J.D.M. Belgers; M-C. Boerwinkel; L. Jollie; M.H.S. Kraak; M.J. Papo; J.A. Vonk; I. Roessink
      Pages: 118 - 128
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): T.C.M. Brock, J.D.M. Belgers, M-C. Boerwinkel, L. Jollie, M.H.S. Kraak, M.J. Papo, J.A. Vonk, I. Roessink
      This paper deals with species sensitivity distributions (SSDs) for the lipophilic insecticide lufenuron and benthic arthropods based on sediment-spiked laboratory toxicity tests. This compound that inhibits chitin synthesis and moulting of arthropods persists in sediment. Using field-collected sediment, toxicity tests were conducted with three macro-crustaceans and six insects. The Hazardous Concentration to 5% of the tested species, the HC5 (and 95% confidence limit), derived from an SSD constructed with 10d-LC50′s was 2.2 (1.2–5.7) μg/g organic carbon (OC) in dry sediment. In addition, HC5 values derived from SSDs constructed with 28d-LC10 and 28-d LC50 values were 0.13 (0.02–1.50) μg/g OC and 2.0 (1.3–5.5) μg/g OC, respectively. In 28d toxicity tests with Chironomus riparius and Hyalella azteca, a higher sensitivity was observed when using lufenuron-spiked field-collected sediment than in lufenuron-spiked artificial sediment. Overall, the non-biting midge C. riparius appeared to be a representative and sensitive standard test species to assess effects of lufenuron exposure in sediment. The Tier-1 (based on standard test species), Tier-2 (based on standard and additional test species) and Tier-3 (model ecosystem approach) regulatory acceptable concentrations (RACs) for sediment-spiked lufenuron did not differ substantially. The Tier-2 RAC was the lowest. Since to our knowledge this study is the first in the open literature that evaluates the tiered approach in the sediment effect assessment procedure for pesticides, we advocate that similar evaluations should be conducted for pesticides that differ in toxic mode-of-action.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.005
      Issue No: Vol. 198 (2018)
       
  • Metabolomic and oxidative effects of quantum dots-indolicidin on three
           generations of Daphnia magna
    • Authors: Annarita Falanga; Flavia A. Mercurio; Antonietta Siciliano; Lucia Lombardi; Stefania Galdiero; Marco Guida; Giovanni Libralato; Marilisa Leone; Emilia Galdiero
      Pages: 158 - 164
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Annarita Falanga, Flavia A. Mercurio, Antonietta Siciliano, Lucia Lombardi, Stefania Galdiero, Marco Guida, Giovanni Libralato, Marilisa Leone, Emilia Galdiero
      This study evaluated the effect of QDs functionalized with the antimicrobial peptide indolicidin on oxidative stress and metabolomics profiles of Daphnia magna across three generations (F0, F1, and F2). Exposing D. magna to sub-lethal concentrations of the complex QDs-indolicidin, a normal survival of daphnids was observed from F0 to F2, but a delay of first brood, fewer broods per female, a decrease of length of about 50% compared to control. In addition, QDs-indolicidin induced a significantly higher production of reactive oxygen species (ROS) gradually in each generation and an impairment of enzymes response to oxidative stress such as superoxide dismutase (SOD), catalase (CAT) and glutathione transferase (GST). Effects were confirmed by metabolomics profiles that pointed out a gradual decrease of metabolomics content over the three generations and a toxic effect of QDs-indolicidin likely related to the higher accumulation of ROS and decreased antioxidant capacity in F1 and F2 generations. Results highlighted the capability of metabolomics to reveal an early metabolic response to stress induced by environmental QDs-indolicidin complex.
      Graphical abstract image

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.001
      Issue No: Vol. 198 (2018)
       
  • Phototoxic effects of PAH and UVA exposure on molecular responses and
           developmental success in coral larvae
    • Authors: Sebastian Overmans; Mikaela Nordborg; Rubén Díaz-Rúa; Diane L. Brinkman; Andrew P. Negri; Susana Agustí
      Pages: 165 - 174
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Sebastian Overmans, Mikaela Nordborg, Rubén Díaz-Rúa, Diane L. Brinkman, Andrew P. Negri, Susana Agustí
      Exposure to polycyclic aromatic carbons (PAHs) poses a growing risk to coral reefs due to increasing shipping and petroleum extraction in tropical waters. Damaging effects of specific PAHs can be further enhanced by the presence of ultraviolet radiation, known as phototoxicity. We tested phototoxic effects of the PAHs anthracene and phenanthrene on larvae of the scleractinian coral Acropora tenuis in the presence and absence of UVA (320–400 nm). Activity of superoxide dismutase (SOD) enzyme was reduced by anthracene while phenanthrene and UVA exposure did not have any effect. Gene expression of MnSod remained constant across all treatments. The genes Catalase, Hsp70 and Hsp90 showed increased expression levels in larvae exposed to anthracene, but not phenanthrene. Gene expression of p53 was upregulated in the presence of UVA, but downregulated when exposed to PAHs. The influence on stress-related biochemical pathways and gene expresson in A. tenuis larvae was considerably greater for anthracene than phenanthrene, and UVA-induced phototoxicity was only evident for anthracene. The combined effects of UVA and PAH exposure on larval survival and metamorphosis paralleled the sub-lethal stress responses, clearly highlighting the interaction of UVA on anthracene toxicity and ultimately the coral’s development.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.008
      Issue No: Vol. 198 (2018)
       
  • Cardiometabolic response of juvenile rainbow trout exposed to dietary
           selenomethionine
    • Authors: Connor M. Pettem; Jennifer M. Briens; David M. Janz; Lynn P. Weber
      Pages: 175 - 189
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Connor M. Pettem, Jennifer M. Briens, David M. Janz, Lynn P. Weber
      Selenium (Se) is considered an essential trace element, involved in important physiological and metabolic functions for all vertebrate species. Fish require dietary concentrations of 0.1–0.5 μg Se/g dry mass (d.m.) to maintain normal physiological and selenoprotein function, however concentrations exceeding 3 μg/g d.m. have been shown to cause toxicity. As Se is reported to have a narrow margin between essentiality and toxicity, there is growing concern surrounding the adverse effects of elevated Se exposure caused by anthropogenic activities. Previous studies have reported that elevated dietary exposure of fish to selenomethionine (Se-Met) can cause significant cardiotoxicity and alter aerobic metabolic capacity, energy homeostasis and swimming performance. The goal of this study aims to further investigate mechanisms of sublethal Se-Met toxicity, particularly potential underlying cardiovascular and metabolic implications of chronic exposure to environmentally relevant concentrations of dietary Se-Met in juvenile rainbow trout (Oncorhynchus mykiss). Juvenile rainbow trout were fed either control food (1.3 μg Se/g d.m.) or Se-Met spiked food (6.4, 15.8 or 47.8 μg Se/g d.m.) for 60 d at 3% body weight per day. Following exposure, ultrahigh resolution B-mode and Doppler ultrasound was used to characterize cardiac function in vivo. Chronic dietary exposure to Se-Met significantly increased stroke volume, cardiac output, and ejection fraction. Fish fed with Se-Met spiked food had elevated liver glycogen and triglyceride stores, suggesting impaired energy homeostasis. Exposure to Se-Met significantly decreased mRNA abundance of citrate synthase (CS) in liver and serpin peptidase inhibitor, clad H1 (SERPINH) in heart, and increased mRNA abundance of sarcoplasmic reticulum calcium ATPase (SERCA) and key cardiac remodelling enzyme matrix metalloproteinase 9 (MMP9) in heart. Taken together, these responses are consistent with a compensatory cardiac response to increased susceptibility to oxidative stress, namely a decrease in ventricular stiffness and improved cardiac function. These cardiac alterations in trout hearts were linked to metabolic disruption in other major metabolic tissues (liver and skeletal muscle), impaired glucose tolerance with increased levels of the toxic glucose metabolite, methylglyoxal, increased lipid peroxidation in skeletal muscle, development of cataracts and prolonged feeding behaviour, indicative of visual impairment. Therefore, although juvenile rainbow trout hearts were apparently able to functionally compensate for adverse metabolic and anti-oxidant changes after chronic dietary exposure Se-Met, complications associated with hyperglycemia in mammalian species were evident and would threaten survival of juvenile and adult fish.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.02.022
      Issue No: Vol. 198 (2018)
       
  • Miniaturised Marine Algae Test with Polycyclic Aromatic Hydrocarbons −
           Comparing Equilibrium Passive Dosing and Nominal Spiking
    • Authors: Nora Claire Niehus; Carolin Floeter; Henner Hollert; Gesine Witt
      Pages: 190 - 197
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Nora Claire Niehus, Carolin Floeter, Henner Hollert, Gesine Witt
      In this study the miniaturised Marine Algae Test (mMAT) using passive dosing was developed based on the ISO EN DIN10253 to investigate the growth inhibition of the marine diatom Phaeodactylum tricornutum caused by polycyclic aromatic hydrocarbons (PAHs). Risk assessment of hydrophobic organic compounds (HOCs) like PAHs in aquatic toxicity tests is very difficult due to their low aqueous solubilities, losses via sorption to the wells and volatilisation. However, passive dosing can overcome these challenges. In this study biocompatible silicone O-rings were used as PAH reservoir. Individual PAHs at saturation were tested using passive dosing and in comparison with nominal spiking. Additionally, a recreated mixture of PAHs reflecting the field composition of the sediment pore water was tested with passive dosing. PAHs revealed strong growth inhibiting effects on algal growth in passive dosing tests, while nominal spiking had only slightly growth inhibiting effects in the highest concentration. The recreated PAH mixture revealed slightly inhibiting effects using passive dosing when tested with a factor of 5000 of the field concentration. This study demonstrates the superiority of passive dosing to spiking and further the successful implementation of passive dosing in the marine algae test maintaining a constant concentration for HOCs with a log KOW > 4.6.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.002
      Issue No: Vol. 198 (2018)
       
  • RIBE at an inter-organismic level: A study on genotoxic effects in Daphnia
           magna exposed to waterborne uranium and a uranium mine effluent
    • Authors: P. Reis; J. Lourenço; F.P. Carvalho; J. Oliveira; M. Malta; S. Mendo; R. Pereira
      Pages: 206 - 214
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): P. Reis, J. Lourenço, F.P. Carvalho, J. Oliveira, M. Malta, S. Mendo, R. Pereira
      The induction of RIBE (Radiation Induced Bystander Effect) is a non-target effect of low radiation doses that has already been verified at an inter-organismic level in fish and small mammals. Although the theoretical impact in the field of environmental risk assessment (ERA) is possible, there is a gap of knowledge regarding this phenomenon in invertebrate groups and following environmentally relevant exposures. To understand if RIBE should be considered for ERA of radionuclide-rich wastewaters, we exposed Daphnia magna (<24 h and 5d old) to a 2% diluted uranium mine effluent for 48 h, and to a matching dose of waterborne uranium (55.3 μg L−1). Then the exposed organisms were placed (24 and 48 h) in a clean medium together with non-exposed neonates. The DNA damage observed for the non-exposed organisms was statistically significant after the 24 h cohabitation for both uranium (neonates p = 0.002; 5 d-old daphnids p = <0.001) and uranium mine effluent exposure (only for neonates p = 0.042). After 48 h cohabitation significant results were obtained only for uranium exposure (neonates p = 0.017; 5 d-old daphnids p = 0.013). Although there may be some variability associated to age and exposure duration, the significant DNA damage detected in non-exposed organisms clearly reveals the occurrence of RIBE in D. magna. The data obtained and here presented are a valuable contribution for the discussion about the relevance of RIBE for environmental risk assessment.
      Graphical abstract image

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.007
      Issue No: Vol. 198 (2018)
       
  • Multi biomarker analysis of pollution effect on resident populations of
           blue mussels from the Baltic Sea
    • Authors: Josefine Larsson; Katarzyna Smolarz; Justyna Świeżak; Magda Turower; Natalia Czerniawska; Mats Grahn
      Pages: 240 - 256
      Abstract: Publication date: May 2018
      Source:Aquatic Toxicology, Volume 198
      Author(s): Josefine Larsson, Katarzyna Smolarz, Justyna Świeżak, Magda Turower, Natalia Czerniawska, Mats Grahn
      Anthropogenic pollution including metals, petroleum, toxins, nutrients and many others is a growing problem in the marine environment. These are important factors altering the environment and by that the fate of many local populations of marine organisms. The aim of this study was to assess the impact of selected point pollution sources on resident populations of the blue mussel (Mytilus edulis trossulus) in the Baltic Sea using multiple biomarker approach. The study used a nested sampling scheme in which sites from reference (REF) habitats are geographically paired with selected sites from sewage treatment plants (STP) and harbors (HAR). The results showed that mussels from harbors had a higher frequency of histological abnormalities in the digestive gland compared to mussels from sewage effluent affected areas and reference sites. However these mussels together with mussels from STPs had higher lipid content, body mass index (BMI) and gonado-somatic index (GSI) compared to mussels from reference sites. A marked spatial variability was found with a stronger toxicity of ambient environment affecting resident mussel populations in the Gulf of Gdańsk area, while an opposite pattern was found in Tvärminne area. Yet the blue mussels sampled in the Gulf of Gdańsk were characterized by the highest GSI and BMI values compared to Askö and Tvärminne populations. No differences in analyzed biomarker response related to species identity, measured by a species-specific genetic marker, were found indicative of strong genetic introgression in the Baltic Proper.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.02.024
      Issue No: Vol. 198 (2018)
       
  • A protective role for autophagy in TDCIPP-induced developmental
           neurotoxicity in zebrafish larvae
    • Authors: Ruiwen Li; Ling Zhang; Qipeng Shi; Yongyong Guo; Wei Zhang; Bingsheng Zhou
      Abstract: Publication date: Available online 15 March 2018
      Source:Aquatic Toxicology
      Author(s): Ruiwen Li, Ling Zhang, Qipeng Shi, Yongyong Guo, Wei Zhang, Bingsheng Zhou
      Tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP), an extensively used organophosphorus flame retardant, is frequently detected in various environmental media and biota, and has been demonstrated as neurotoxic. Autophagy has been proposed as a protective mechanism against toxicant-induced neurotoxicity. The purpose of the present study was to investigate the effect of TDCIPP exposure on autophagy, and its role in TDCIPP-induced developmental neurotoxicity. Zebrafish embryos (2–120 h post-fertilization [hpf]) were exposed to TDCIPP (0, 5, 50 and 500 μg/l) and a model neurotoxic chemical, chlorpyrifos (CPF, 100 μg/l). The developmental endpoints, locomotive behavior, cholinesterase activities, gene and protein expression related to neurodevelopment and autophagy were measured in the larvae. Our results demonstrate that exposure to TDCIPP (500 μg/l) and CPF causes developmental toxicity, including reduced hatching and survival rates and increased malformation rate (e.g., spinal curvature), as well as altered locomotor behavior. The expression of selected neurodevelopmental gene and protein markers (e.g., mbp, syn2a, and α1-tubulin) was significantly down-regulated in CPF and TDCIPP exposed zebrafish larvae. Treatment with CPF significantly inhibits AChE and BChE, while TDCIPP (0–500 μg/l) exerts no effects on these enzymes. Furthermore, the conversion of microtubule-associated protein I (LC3 I) to LC3 II was significantly increased in TDCIPP exposed zebrafish larvae. In addition, exposure to TDCIPP also activates transcription of several critical genes in autophagy (e.g. Becn1, atg3, atg5, map1lc3b and sqstm1). To further investigate the role of autophagy in TDCIPP induced developmental neurotoxicity, an autophagy inducer (rapamycin, Rapa, 1 nM) and inhibitor (chloroquine, CQ, 1 μM) were used. The results demonstrate that the hatching rate, survival rate, and the expression of mbp and а1-tubulin proteins were all significantly increased in larvae treated with TDCIPP (500 μg/l) and Rapa compared to TDCIPP alone. In contrast, co-treatment with the autophagy inhibitor CQ results in exacerbated neurodevelopmental toxicity. Taken together, our results confirm that exposure to TDCIPP induces autophagy, which plays a protective role in TDCIPP-induced developmental neurotoxicity in zebrafish embryos and larvae.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.016
       
  • Tris (2-butoxyethyl) phosphate affects motor behavior and axonal growth in
           zebrafish (Danio rerio) larvae
    • Authors: Fan Jiang; Jue Liu Xinyue Zeng Liqin Chunsheng Liu Jianghua
      Abstract: Publication date: Available online 13 March 2018
      Source:Aquatic Toxicology
      Author(s): Fan Jiang, Jue Liu, Xinyue Zeng, Liqin Yu, Chunsheng Liu, Jianghua Wang
      Tris (2-butoxyethyl) phosphate (TBOEP) is an environmental contaminant that poses serious risks to aquatic organisms and their associated ecosystem. Recently, the reproductive and developmental toxicology of TBOEP has been reported. However, fewer studies have assessed the neurotoxic effects in zebrafish (Danio rerio) larvae. In this study, zebrafish embryos were subjected to waterborne exposure of TBOEP at 0, 50, 500, 1500 and 2500 μg/L from 2 to 144-h post-fertilization (hpf). Behavioral measurements showed that TBOEP exposure reduced embryonic spontaneous movement and decreased swimming speed of larvae in response to dark stimulation. In accordance with these motor effects, TBOEP treatment reduced neuron-specific GFP expression in transgenic Tg (HuC-GFP) zebrafish larvae and inhibited the growth of secondary motoneurons, as well as decreased expression of marker genes related to central nervous system development in TBOEP treated group. Furthermore, increased concentrations of reactive oxygen species (ROS) and malondialdehyde (MDA), as well as reduction of SOD activity were detected in TBOEP exposure group. The present results showed that the alteration in motor neuron and oxidative stress could together lead to the motor behavior alterations induced by TBOEP.

      PubDate: 2018-03-17T10:50:19Z
       
  • Alterations of secondary sex characteristics, reproductive histology and
           behaviors by norgestrel in the western mosquitofish (Gambusia affinis)
    • Authors: Li-ping Hou; Hongxing Chen Chang-en Tian Liang Rong-rong Xing-mei Zhang
      Abstract: Publication date: Available online 13 March 2018
      Source:Aquatic Toxicology
      Author(s): Li-ping Hou, Hongxing Chen, Chang-en Tian, Ye Liang, Rong-rong Wu, Xing-mei Zhang, Xu-wen Fang, Cui-ping Zhang, Jun-jie Hu, Li-ying Song, Yan-qiu Liang, Daniel Schlenk, Lingtian Xie
      Synthetic hormones in wastewater effluents released into the aquatic environments may interfere with the normal endocrine systems of fish in receiving streams. Norgestrel (NGT) is a synthetic progestin widely used in oral contraceptives and frequently detected in wastewater effluents. In this study, adult female mosquitofish (Gambusia affinis) were exposed to three environmentally relevant concentrations of norgestrel (NGT) (i.e., 3.6, 35.8, and 368.0 ng L−1) for 42 d, fin morphology, histology of the ovary, and reproductive behaviors were evaluated. The results showed that NGT at all three concentrations caused an increased frequency of atretic follicular cells in ovaries and impaired mating behaviors exhibited by males toward the NGT-exposed females. In mosquitofish exposed to NGT at 35.8 and 368 ng L−1, the anal fin of females had an increased length ratio of ray4/ray 6, an increased width of ray 3, and increased number of segments in ray 3. The histopathological analysis showed that exposure to NGT increased the incidence of spermatogenesis in ovaries. Mating behavior was impaired 58.4%, 65.7%, and 76.4% (P < 0.01 in all cases) in when mosquitofish were exposed to NGT at 3.6, 35.6 and 368.0 ng L−1, respectively. The rapid masculinization, the increased frequency of atretic follicles, the incidence of spermatogenesis in the ovary of female fish, and the altered reproductive behaviors suggest that wild populations of mosquitofish could be similarly affected inhabiting in NGT contaminated environments.

      PubDate: 2018-03-17T10:50:19Z
       
  • Complex role of titanium dioxide nanoparticles in the trophic transfer of
           arsenic from Nannochloropsis maritima to Artemia salina nauplii
    • Authors: Fan Yang; Liqing Zeng; Zhuanxi Luo; Zaosheng Wang; Fuyi Huang; Qiuquan Wang; Damjana Drobne; Changzhou Yan
      Abstract: Publication date: Available online 10 March 2018
      Source:Aquatic Toxicology
      Author(s): Fan Yang, Liqing Zeng, Zhuanxi Luo, Zaosheng Wang, Fuyi Huang, Qiuquan Wang, Damjana Drobne, Changzhou Yan
      Increasing concern has been focused on the potential risks associated with the trophic transfer to aquatic organisms of ambient contaminants in the presence of titanium dioxide nanoparticles (nano-TiO2). This study investigated the influence of nano-TiO2 on the trophic transfer of arsenic (As) from the microalgae Nannochloropsis maritima to the brine shrimp Artemia salina nauplii. We found that nano-TiO2 could significantly facilitate As sorption on N. maritima within an exposure period of 24 h, and this sorption subsequently led to higher As trophic transfer from the algae to A. salina according to trophic transfer factors (TTF As +nano-TiO2 > TTF As ). However, after 48 h of depuration, the retention of As in A. salina fed As-nano-TiO2-contaminated algae was even lower than that in A. salina fed As-contaminated algae at the same exposure concentrations. This result indicates that the increased food chain transfer of As in the presence of nano-TiO2 can be explained by adsorption of As onto nano-TiO2 in contaminated food (algae), but the bioavailability of As in A. salina is reduced after the introduction of nanoparticles. Although the stress enzyme activities of superoxide dismutase (SOD) and acetylcholinesterase (AChE) in A. salina at a lower As concentration treatment in the presence of nano-TiO2 were not significantly changed, they increased with higher exposure concentrations of As with or without nano-TiO2. Our study highlighted the complex role of nanomaterials in the transfer of ambient contaminants via trophic chains and the potential of nano-TiO2 to reduce the bioavailability of As via trophic transfer to saltwater zooplankton.

      PubDate: 2018-03-17T10:50:19Z
      DOI: 10.1016/j.aquatox.2018.03.009
       
  • Short-term developmental effects and potential mechanisms of azoxystrobin
           in larval and adult zebrafish (Danio rerio)
    • Authors: Fangjie Cao; Peizhuo Wu; Lan Huang; Hui Li; Le Qian; Sen Pang; Lihong Qiu
      Abstract: Publication date: Available online 6 March 2018
      Source:Aquatic Toxicology
      Author(s): Fangjie Cao, Peizhuo Wu, Lan Huang, Hui Li, Le Qian, Sen Pang, Lihong Qiu
      Previous study indicated that azoxystrobin had high acute toxicity to zebrafish, and larval zebrafish were more sensitive to azoxystrobin than adult zebrafish. The objective of the present study was to investigate short-term developmental effects and potential mechanisms of azoxystrobin in larval and adult zebrafish. After zebrafish embryos and adults were exposed to 0.01, 0.05 and 0.20 mg/L azoxystrobin (equal to 25, 124 and 496 nM azoxystrobin, respectively) for 8 days, the lethal effect, physiological responses, liver histology, mitochondrial ultrastructure, and expression alteration of genes related to mitochondrial respiration, oxidative stress, cell apoptosis and innate immune response were determined. The results showed that there was no significant effect on larval and adult zebrafish after exposure to 0.01 mg/L azoxystrobin. However, increased ROS, MDA concentration and il1b in larval zebrafish, as well as increased il1b, il8 and cxcl-c1c in adult zebrafish were induced after exposure to 0.05 mg/L azoxystrobin. Reduced mitochondrial complex III activity and ATP concentration, increased SOD activity, ROS and MDA concentration, decreased cytb, as well as increased sod1, sod2, cat, il1b, il8 and cxcl-c1c were observed both in larval and adult zebrafish after exposure to 0.20 mg/L azoxystrobin; meanwhile, increased p53, bax, apaf1 and casp9, alteration of liver histology and mitochondrial ultrastructure in larval zebrafish, and alteration of mitochondrial ultrastructure in adult zebrafish were also induced. The results demonstrated that azoxytrobin induced short-term developmental effects on larval zebrafish and adult zebrafish, including mitochondrial dysfunction, oxidative stress, cell apoptosis and innate immune response. Statistical analysis indicated that azoxystrobin induced more negative effects on larval zebrafish, which might be the reason for the differences of developmental toxicity between larval and adult zebrafish caused by azoxystrobin. These results provided a new insight into potential mechanisms of azoxystrobin in larval zebrafish and adult zebrafish.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.02.023
       
  • The role of marine biotoxins on the trophic transfer of Mn and Zn in fish
    • Authors: Simon Pouil; Rachel Clausing; Marc Metian; Paco Bustamante; Marie-Yasmine Dechraoui Bottein
      Abstract: Publication date: Available online 5 March 2018
      Source:Aquatic Toxicology
      Author(s): Simon Pouil, Rachel Clausing, Marc Metian, Paco Bustamante, Marie-Yasmine Dechraoui Bottein
      Essential nutrients are critical for organismal physiological processes. In fish, they are obtained primarily from the diet, and their transfer and accumulation are known to be impacted by environmental variables such as water temperature, pH and salinity, as well as by diet composition and matrices. Yet, prey items consumed by fish may also contain toxic compounds such as marine toxins associated with harmful algae. These biotoxins have the potential to affect essential trace element assimilation in fish through chemical interactions such as the formation of trace element-toxin complexes or by affecting general fish physiology as in the modification of ion-specific transport pathways. We assessed the influence of dietary exposure to brevetoxins (PbTxs), ichthyotoxic neurotoxins produced by the dinoflagellate Karenia brevis, on trophic transfer of two essential trace elements, Mn and Zn in a fish model. Using ecologically relevant concentrations of PbTxs and trace elements in controlled laboratory conditions, juvenile turbots Scophthalmus maximus were given food containing PbTxs before or at the same time as a feeding with radiotracers of the chosen essential elements (54Mn and 65Zn). Treatments included simultaneous exposure (PbTxs + 54Mn + 65Zn) in a single-feeding, and 3-week daily pre-exposure to dietary PbTx followed by a single feeding with 54Mn and 65Zn, and a control (54Mn and 65Zn only). After a 21-day depuration period, turbot tissue brevetoxin levels were quantified and assimilation efficiencies of 54Mn and 65Zn were assessed. PbTxs were found in turbot tissues in each exposure treatment, demonstrating dietary trophic transfer of these toxins; yet, no differences in assimilation efficiencies of Mn or Zn were found between treatments or the control (p > 0.05). These results indicate that, in our experimental conditions, PbTx exposure does not significantly affect the trophic transfer of Mn and Zn in fish.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.03.004
       
  • The Cytotoxicity and Genotoxicity of Particulate and Soluble Hexavalent
           Chromium in Leatherback Sea Turtle Lung Cells
    • Authors: Rachel M. Speer; Catherine F. Wise; Jamie L. Young; Abou El-Makarim Aboueissa; Mark Martin Bras; Mike Barandiaran; Erick Bermúdez; Lirio Márquez-D’Acunti; John Pierce Wiser
      Abstract: Publication date: Available online 4 March 2018
      Source:Aquatic Toxicology
      Author(s): Rachel M. Speer, Catherine F. Wise, Jamie L. Young, Abou El-Makarim Aboueissa, Mark Martin Bras, Mike Barandiaran, Erick Bermúdez, Lirio Márquez-D’Acunti, John Pierce Wiser
      Hexavalent chromium [Cr(VI)] is a marine pollution of concern as recent studies show it has a global distribution, with some regions showing high Cr concentrations in marine animal tissue, and it is extensively used. Leatherback sea turtles (Dermochelys coriacea) are an endangered marine species that may experience prolonged exposures to environmental contaminants including Cr(VI). Human activities have led to global Cr(VI) contamination of the marine environment. While Cr(VI) has been identified as a known human carcinogen, the health effects in marine species are poorly understood. In this study, we assessed the cytotoxic and genotoxic effects of particulate and soluble Cr(VI) in leatherback sea turtle lung cells. Both particulate and soluble Cr(VI) induced a concentration-dependent increase in cytotoxicity. Next, using a chromosome aberration assay, we assessed the genotoxic effects of Cr(VI) in leatherback sea turtles. Particulate and soluble Cr(VI) induced a concentration-dependent increase in clastogenicity in leatherback sea turtle lung cells. These data indicate that Cr(VI) may be a health concern for leatherback sea turtles and other long-lived marine species. Additionally, these data provide foundational support to use leatherback sea turtles are a valuable model species for monitoring the health effects of Cr(VI) in the environment and possibly as an indicator species to assess environmental human exposures and effects.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.03.003
       
  • Early life stages of Northern shrimp (Pandalus borealis) are sensitive to
           fish feed containing the anti-parasitic drug diflubenzuron
    • Authors: Renée Katrin Bechmann; Emily Lyng; Stig Westerlund; Shaw Bamber; Mark Berry; Maj Arnberg; Alfhild Kringstad; Piero Calosi; Paul J. Seear
      Abstract: Publication date: Available online 28 February 2018
      Source:Aquatic Toxicology
      Author(s): Renée Katrin Bechmann, Emily Lyng, Stig Westerlund, Shaw Bamber, Mark Berry, Maj Arnberg, Alfhild Kringstad, Piero Calosi, Paul J. Seear
      Increasing use of fish feed containing the chitin synthesis inhibiting anti-parasitic drug diflubenzuron (DFB) in salmon aquaculture has raised concerns over its impact on coastal ecosystems. Larvae of Northern shrimp (Pandalus borealis) were exposed to DFB medicated feed under Control conditions (7.0 °C, pH 8.0) and under Ocean Acidification and Warming conditions (OAW, 9.5 °C and pH 7.6). Two weeks’ exposure to DFB medicated feed caused significantly increased mortality. The effect of OAW and DFB on mortality of shrimp larvae was additive; 10% mortality in Control, 35% in OAW, 66% in DFB and 92% in OAW + DFB. In OAW + DFB feeding and swimming activity were reduced for stage II larvae and none of the surviving larvae developed to stage IV. Two genes involved in feeding (GAPDH and PRLP) and one gene involved in moulting (DD9B) were significantly downregulated in larvae exposed to OAW + DFB relative to the Control. Due to a shorter intermoult period under OAW conditions, the OAW + DFB larvae were exposed throughout two instead of one critical pre-moult period. This may explain the more serious sub-lethal effects for OAW + DFB than DFB larvae. A single day exposure at 4 days after hatching did not affect DFB larvae, but high mortality was observed for OAW + DFB larvae, possibly because they were exposed closer to moulting. High mortality of shrimp larvae exposed to DFB medicated feed, indicates that the use of DFB in salmon aquaculture is a threat to crustacean zooplankton.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.02.021
       
  • Genotoxicity and physiological effects of CeO2 NPs on a freshwater bivalve
           (Corbicula fluminea)
    • Authors: Vanessa Koehle-divo; Carole Cossu-Leguille; Sandrine Pain-Devin; Cécile Simonin; Carole Bertrand; Bénédicte Sohm; Catherine Mouneyrac; Simon Devin; Laure Giamberini
      Abstract: Publication date: Available online 27 February 2018
      Source:Aquatic Toxicology
      Author(s): Vanessa Koehle-divo, Carole Cossu-Leguille, Sandrine Pain-Devin, Cécile Simonin, Carole Bertrand, Bénédicte Sohm, Catherine Mouneyrac, Simon Devin, Laure Giamberini
      The rapid development of nanotechnology and the increased use of nanomaterials in products used in everyday life have raised the question of the potential release of nanoparticles into the aquatic environment. Their fate and effects in natural ecosystems are not currently well understood but harmful effects of nanoparticles have been demonstrated at low concentrations on some freshwater and marine species. Cerium dioxide nanoparticles (CeO2 NPs) are produced in large quantities and used in products in many different fields, such as automotives or optics. Because of their widespread use in daily products, CeO2 NPs are included in the OECD priority list of manufactured nanomaterials for human and environmental assessment. Indeed some studies have been conducted to assay various enzymatic biomarkers, which showed the CeO2 NPs potential to modify anti-oxidative defenses and cellular membrane stability. Nevertheless, only a few studies were performed on their genotoxic potential. The aim of this work was to evaluate the genotoxic and physiological effects of CeO2 NPs on a widespread freshwater bivalve Corbicula fluminea by using comet assay and a multi-enzymatic biomarker approach. Exposure to two CeO2 NP concentrations during a short term experiment (6 days) was set up. The first one (10 μg/L) was chosen in order to work with low but measurable concentrations whereas the second one was ten times higher (100 μg CeO2 NPs/L). DNA damage was significantly more pronounced compared with control for both concentrations tested as early as two days of exposure and seemed to increase with time. Some enzymatic biomarkers of anti-oxidative defenses (total antioxidant capacity, catalase activity), anti-toxic mechanisms (glutathione-S-transferase activity, caspase-3 activity) or metabolism (lactate dehydrogenase activity) tended to increase after 6 days of exposure but only the induction of caspase pathway and DNA damages appeared significant for exposed organisms. In this study, time and concentration effects of CeO2 NPs were highlighted by coupling genotoxic and cellular biomarker assessments.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.02.020
       
  • The influence of natural dissolved organic matter on herbicide toxicity to
           marine microalgae is species-dependent
    • Authors: Nathalie Coquillé; Dominique Ménard; Julien Rouxel; Valentin Dupraz; Mélissa Éon; Patrick Pardon; Hélène Budzinski; Soizic Morin; Édith Parlanti; Sabine Stachowski-Haberkorn
      Abstract: Publication date: Available online 27 February 2018
      Source:Aquatic Toxicology
      Author(s): Nathalie Coquillé, Dominique Ménard, Julien Rouxel, Valentin Dupraz, Mélissa Éon, Patrick Pardon, Hélène Budzinski, Soizic Morin, Édith Parlanti, Sabine Stachowski-Haberkorn
      Microalgae, which are the foundation of aquatic food webs, may be the indirect target of herbicides used for agricultural and urban applications. Microalgae also interact with other compounds from their environment, such as natural dissolved organic matter (DOM), which can itself interact with herbicides. This study aimed to evaluate the influence of natural DOM on the toxicity of three herbicides (diuron, irgarol and S-metolachlor), singly and in ternary mixtures, to two marine microalgae, Chaetoceros calcitrans and Tetraselmis suecica, in monospecific, non-axenic cultures. Effects on growth, photosynthetic efficiency (Ф’M) and relative lipid content were evaluated. The chemical environment (herbicide and nutrient concentrations, dissolved organic carbon and DOM optical properties) was also monitored to assess any changes during the experiments. The results show that, without DOM, the highest irgarol concentration (I0.5: 0.5 mg L−1) and the strongest mixture (M2: irgarol 0.5 μg L−1 + diuron 0.5 μg L−1 + S-metolachlor 5.0 μg L−1) significantly decreased all parameters for both species. Similar impacts were induced by I0.5 and M2 in C. calcitrans (around −56% for growth, −50% for relative lipid content and −28% for Ф’M), but a significantly higher toxicity of M2 was observed in T. suecica (−56% and −62% with I0.5 and M2 for growth, respectively), suggesting a possible interaction between molecules. With DOM added to the culture media, a significant inhibition of these three parameters was also observed with I0.5 and M2 for both species. Furthermore, DOM modulated herbicide toxicity, which was decreased for C. calcitrans (−51% growth at I0.5 and M2) and increased for T. suecica (-64% and −75% growth at I0.5 and M2, respectively). In addition to the direct and/or indirect (via their associated bacteria) use of molecules present in natural DOM, the characterization of the chemical environment showed that the toxic effects observed on microalgae were accompanied by modifications of DOM composition and the quantity of dissolved organic carbon excreted and/or secreted by microorganisms. This toxicity modulation in presence of DOM could be explained by (i) the modification of herbicide bioavailability, (ii) a difference in cell wall composition between the two species, and/or (iii) a higher detoxification capacity of C. calcitrans by the use of molecules contained in DOM. This study therefore demonstrated, for the first time, the major modulating role of natural DOM on the toxicity of herbicides to marine microalgae.

      PubDate: 2018-03-06T14:50:45Z
      DOI: 10.1016/j.aquatox.2018.02.019
       
  • Evaluation of biomarkers in Mytilus galloprovincialis as an integrated
           measure of biofilm-membrane bioreactor (BF-MBR) system efficiency in
           mitigating the impact of oily wastewater discharge to marine environment:
           a microcosm approach
    • Authors: Cristina Pirrone; Federica Rossi; Simone Cappello; Marina Borgese; Giuseppe Mancini; Giovanni Bernardini; Rosalba Gornati
      Abstract: Publication date: Available online 24 February 2018
      Source:Aquatic Toxicology
      Author(s): Cristina Pirrone, Federica Rossi, Simone Cappello, Marina Borgese, Giuseppe Mancini, Giovanni Bernardini, Rosalba Gornati
      The large volumes of oily wastewater discharged to marine environment cause heavy impacts on the coastal marine ecosystem. The selection of an appropriate technology to reduce these impacts should be based on the respects of the discharge limits and on the effective assessment and monitoring of its effects on biological organism preservation. To this aim, we set up a controlled microcosm-scale system to compare the effects of a treated and untreated oily wastewater discharge in which the restore process is performed through a Membrane Bio-Reactor. The system is completed by other three microcosms to control and isolate any possible concurrent effect on the Mytilus galloprovincialis, used as sentinel organism. Mytilus galloprovincialis have been kept in all these microcosms, and then mRNA expression and morphology were evaluated on gills and digestive gland. The genes considered in this work are Heat Shock Protein 70 and Metallothionein 10, involved in response to physicochemical sublethal stressors and Superoxide dismutase 1, Catalase, and a Cytochrome P450 involved in oxidative stress response. Our results evidenced a significant overexpression, both in gills and digestive gland, of HSP70 in samples maintained in the microcosm receiving the treated effluent, and of MT10 in those animals kept in microcosm where the effluent was treated. Even though the mRNA modifications are considered “primary” and transient responses which do not always correspond to protein content, the study of these modifications can help to gain insights into the mechanisms of action of xenobiotic exposure. Morphological analysis suggested that, although different depending on the microcosm, the most serious damages were found in the gill epithelium accompanied with severe haemocyte infiltration, whilst in digestive gland the tissue architecture alterations and the haemocyte infiltration were less pronounced. These observations suggest that the immune system was activated as a general response to stressful stimuli such as the presence of toxic compounds. Moreover, the results indicate that the treatment process is useful. In fact, samples derived from the microcosm receiving the treated effluent, even though presenting some signs of stress, seemed to partially recover the normal structure, although their mRNA expression indicated some cellular suffering.

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.018
       
  • Melanomacrophage response and hepatic histopathologic biomarkers in the
           
    • Authors: Gabriel Qualhato; Simone Maria Teixeira de Sabóia-Morais; Luciana Damacena Silva; Thiago Lopes Rocha
      Abstract: Publication date: Available online 21 February 2018
      Source:Aquatic Toxicology
      Author(s): Gabriel Qualhato, Simone Maria Teixeira de Sabóia-Morais, Luciana Damacena Silva, Thiago Lopes Rocha
      Although iron oxide nanoparticles (IONPs) have been widely used in nanomedicine and nanoremediation, their ecotoxicological effects on aquatic organisms remain unclear. In this study, the melanomacrophage center (MMC) response and hepatic histopathologic biomarkers were investigated in female guppies, Poecilia reticulata, exposed to citrate-functionalized IONPs (γ-Fe2O3) at an environmentally relevant iron concentration (0.3 mg L−1) over 21 days. The animals were collected at the beginning of the experiment and after 3, 7, 14, and 21 days of exposure. Guppies exposed to IONPs showed increases in the number, area, and perimeter of MMC when compared with the unexposed ones, especially after 7 days of exposure. The results showed an increase in the frequency of histopathologic changes in fish after 7 days of exposure to IONPs, such micro- and macro-vesicular steatosis, melanomacrophage aggregates, exudate, and hemorrhagic foci. The acute (3 and 7 days) and long-term (14 and 21 days) exposure of P. reticulata to IONPs induced high histopathologic indexes associated with circulatory disorders and inflammatory responses. Results showed that the MMC response and histopathologic index are important biomarkers to indicate the environmental impact of IONPs, confirming that the guppy P. reticulata is a target of ecotoxicity of IONPs.
      Graphical abstract image

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.014
       
  • Azoles additively inhibit cytochrome P450 1 (EROD) and 19 (aromatase) in
           rainbow trout (Oncorhynchus mykiss)
    • Authors: Kristina Beijer; Maria Jönsson; Siraz Shaik; Daphné Behrens; Björn Brunström; Ingvar Brandt
      Abstract: Publication date: Available online 21 February 2018
      Source:Aquatic Toxicology
      Author(s): Kristina Beijer, Maria Jönsson, Siraz Shaik, Daphné Behrens, Björn Brunström, Ingvar Brandt
      Antifungal azoles are widely used in medicine, agriculture, and material protection and several antifungal azoles have been found in environmental samples. Although these compounds were designed to inhibit fungal enzymes such as lanosterol-14-demethylase (cytochrome P450 (CYP) 51), it is well established that the inhibitory actions of azoles are not specific for fungal CYP isozymes. We refined a gill filament assay to determine the inhibition of CYP1, measured as reduced 7-ethoxyresorufin-O-deethylase (EROD) activity, in rainbow trout (Oncorhynchus mykiss) gill tissue ex vivo. The advantage of this method is that both induction and inhibition of EROD are performed ex vivo. Among thirteen azoles studied, the five that caused the strongest inhibition of gill EROD activity at a concentration of 5 μM were selected for concentration–response assessment. These compounds (bifonazole, clotrimazole, imazalil, miconazole, and prochloraz) showed IC50 values ranging from 0.1 to 1.5 μM. CYP19 (aromatase) inhibition was measured using microsomes from rainbow trout brains. Concentration-response curves for CYP19 inhibition were determined for letrozole, bifonazole, clotrimazole, imazalil, miconazole and prochloraz, which gave IC50 values ranging from 0.02 to 3.3 μM. It was further found that mixtures of the five most potent azoles reduced both CYP1 and 19 catalytic activity in an additive fashion (IC50 = 0.7 μM and 0.6 μM, in the respective assay). Bifonazole (IC50 = 0.1 μM) is not previously known to inhibit CYP1 activity. The additive inhibition of CYP1 and CYP19 catalytic activity is an important finding of the present study. We conclude that this additive action of azoles could mediate adverse impacts on CYP regulated physiological functions in environmentally exposed fish.

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.016
       
  • Nrf2a Modulates the Embryonic Antioxidant Response to
           Perfluorooctanesulfonic Acid (PFOS) in the Zebrafish, Danio rerio
    • Authors: Karilyn E. Sant; Paul P. Sinno; Haydee M. Jacobs; Alicia R. Timme-Laragy
      Abstract: Publication date: Available online 20 February 2018
      Source:Aquatic Toxicology
      Author(s): Karilyn E. Sant, Paul P. Sinno, Haydee M. Jacobs, Alicia R. Timme-Laragy
      The glutathione redox system undergoes precise and dynamic changes during embryonic development, protecting against and mitigating oxidative insults. The antioxidant response is coordinately largely by the transcription factor Nuclear factor erythroid-2 (Nrf2), an endogenous sensor for cellular oxidative stress. We have previously demonstrated that impaired Nrf family signaling disrupts the glutathione redox system in the zebrafish embryo, and that impaired Nrf2 function increases embryonic sensitivity to environmental toxicants. Here, we investigated the persistent environmental toxicant and reported pro-oxidant perfluorooctanesulfonic acid (PFOS), and its impact on the embryonic glutathione-mediated redox environment. We further examined whether impaired Nrf2a function exacerbates PFOS-induced oxidative stress and embryotoxicity in the zebrafish, and the potential for Nrf2-PPAR crosstalk in the embryonic adaptive response. Wild-type and nrf2afh318−/− mutant embryos were exposed daily to 0 (0.01% v/v DMSO), 16, 32, or 64 μM PFOS beginning at 3 hours post fertilization (hpf). Embryonic glutathione and cysteine redox environments were examined at 72 hpf. Gross embryonic toxicity, antioxidant gene expression, and apoptosis were examined at 96 hpf. Mortality, pericardial edema, and yolk sac utilization were increased in wild-type embryos exposed to PFOS. Embryonic glutathione and cysteine redox couples and gene expression of Nrf2 pathway targets were modulated by both exposure and genotype. Apoptosis was increased in PFOS-exposed wild-type embryos, though not in nrf2a mutants. In silico examination of putative transcription factor binding site suggested potential crosstalk between Nrf2 and PPAR signaling, since expression of PPARs and gene targets was modulated by both PFOS exposure and Nrf2a genotype. Overall, this work demonstrates that nrf2a modulates the embryonic response to PFOS, and that PPAR signaling may play a role in the embryonic adaptive response to PFOS.

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.010
       
  • The effects of chronic acetaminophen exposure on the kidney, gill and
           liver in rainbow trout (Oncorhynchus mykiss)
    • Authors: Eugene Choi; Derek Alsop; Joanna Y. Wilson
      Abstract: Publication date: Available online 15 February 2018
      Source:Aquatic Toxicology
      Author(s): Eugene Choi, Derek Alsop, Joanna Y. Wilson
      In this study, we examined if rainbow trout chronically exposed to acetaminophen (10 and 30 μgL−1) showed histological changes that coincided with functional changes in the kidney, gill and liver. Histological changes in the kidney included movement and loss of nuclei, non-uniform nuclei size, non-uniform cytoplasmic staining, and loss of tubule integrity. Histological effects were more severe at the higher concentration and coincided with concentration dependent increases in urine flow rate and increased urinary concentrations of sodium, chloride, potassium, calcium, urea, ammonia, glucose, and protein. Yet, glomerular filtration rate was not altered with acetaminophen exposure. In the gill, filament end swelling, whole filament swelling, and swelling of the lamellae were observed in exposed fish. Lamellar spacing decreased in both exposure groups, but lamellar area decreased only with 30 μgL−1 exposure. At faster swimming speeds, oxygen consumption was limited in acetaminophen exposed fish, and critical swimming speed was also decreased in both exposure groups. The liver showed decreased perisinusoidal spaces at 10 and 30 μgL−1 acetaminophen, and decreased cytoplasmic vacuolation with 30 μgL−1 acetaminophen. A decrease in liver glycogen was also observed at 30 μgL−1. There was no change in plasma concentrations of sodium, chloride, potassium, calcium, magnesium, and glucose with exposure, suggesting compensation for urinary loss. Indeed, an increase in Na+-K+-ATPase activity in the gills was found with 30 μgL−1 acetaminophen exposure. Chronic exposure of rainbow trout to the environmentally relevant pharmaceutical acetaminophen, alters both histology and function of organs responsible for ion and nutrient homeostasis.

      PubDate: 2018-02-25T09:07:50Z
      DOI: 10.1016/j.aquatox.2018.02.007
       
 
 
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