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  Subjects -> BIOLOGY (Total: 2982 journals)
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BIOLOGY (1420 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 18)
Achievements in the Life Sciences     Open Access   (Followers: 4)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 20)
Acta Biologica Colombiana     Open Access   (Followers: 6)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 4)
Acta Biologica Sibirica     Open Access  
Acta Biomaterialia     Hybrid Journal   (Followers: 25)
Acta Biotheoretica     Hybrid Journal   (Followers: 5)
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 Parasitologica     Hybrid Journal   (Followers: 9)
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)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Bioinformatics     Open Access   (Followers: 18)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4)
Advances in Biology     Open Access   (Followers: 8)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Advances in Cell Biology     Open Access   (Followers: 23)
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: 11)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Ecological Research     Full-text available via subscription   (Followers: 39)
Advances in Ecology     Open Access   (Followers: 13)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 20)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Genome Biology     Full-text available via subscription   (Followers: 12)
Advances in High Energy Physics     Open Access   (Followers: 20)
Advances in Human Biology     Open Access  
Advances in Life Science and Technology     Open Access   (Followers: 14)
Advances in Life Sciences     Open Access   (Followers: 4)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3)
Advances in Regenerative Biology     Open Access   (Followers: 1)
Advances in Structural Biology     Full-text available via subscription   (Followers: 7)
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: 7)
Aging Cell     Open Access   (Followers: 9)
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: 13)
AJP Endocrinology and Metabolism     Full-text available via subscription   (Followers: 22)
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: 12)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 10)
American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Human Biology     Hybrid Journal   (Followers: 12)
American Journal of Medical and Biological Research     Open Access   (Followers: 5)
American Journal of Plant Sciences     Open Access   (Followers: 19)
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: 63)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 7)
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: 8)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18)
Annals of Human Biology     Hybrid Journal   (Followers: 4)
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 17)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 25)
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: 14)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 18)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 23)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antibiotics     Open Access   (Followers: 8)
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: 9)
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: 4)
Aquatic Ecology     Hybrid Journal   (Followers: 30)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 13)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 19)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biomedical Sciences     Open Access   (Followers: 7)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Archives of Natural History     Hybrid Journal   (Followers: 7)
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: 3)
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: 2)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 1)
Asian Journal of Biodiversity     Open Access   (Followers: 5)
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: 2)
Asian Journal of Nematology     Open Access   (Followers: 3)
Asian Journal of Poultry Science     Open Access   (Followers: 4)
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 5)
Autophagy     Hybrid Journal   (Followers: 2)
Avian Biology Research     Full-text available via subscription   (Followers: 3)
Avian Conservation and Ecology     Open Access   (Followers: 7)
Bacteriology Journal     Open Access   (Followers: 2)
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     Full-text available via subscription   (Followers: 14)
Biochimie     Hybrid Journal   (Followers: 7)
BioControl     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodemography and Social Biology     Hybrid Journal   (Followers: 1)
Biodiversidad Colombia     Open Access  
Biodiversity : Research and Conservation     Open Access   (Followers: 26)
Biodiversity and Natural History     Open Access   (Followers: 5)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     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: 3)
Biogeosciences (BG)     Open Access   (Followers: 9)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 1)
Bioinformatics     Hybrid Journal   (Followers: 231)
Bioinformatics and Biology Insights     Open Access   (Followers: 14)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 6)
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: 4)
Biological Control     Hybrid Journal   (Followers: 5)
Biological Invasions     Hybrid Journal   (Followers: 16)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 14)
Biological Letters     Open Access   (Followers: 4)
Biological Procedures Online     Open Access  
Biological Psychiatry     Hybrid Journal   (Followers: 41)
Biological Psychology     Hybrid Journal   (Followers: 6)
Biological Research     Open Access  
Biological Rhythm Research     Hybrid Journal   (Followers: 2)
Biological Theory     Hybrid Journal   (Followers: 1)
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: 44)
Biologija     Open Access  
Biology     Open Access   (Followers: 5)
Biology and Philosophy     Hybrid Journal   (Followers: 16)
Biology Bulletin     Hybrid Journal   (Followers: 1)
Biology Bulletin Reviews     Hybrid Journal  
Biology Direct     Open Access   (Followers: 7)
Biology Letters     Full-text available via subscription   (Followers: 35)
Biology Methods and Protocols     Hybrid Journal  

        1 2 3 4 5 6 7 8 | Last

Journal Cover Aquatic Toxicology
  [SJR: 1.671]   [H-I: 105]   [19 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0166-445X - ISSN (Online) 1879-1514
   Published by Elsevier Homepage  [3031 journals]
  • Phylogenetic signals in detoxification pathways in Cyprinid and
           Centrarchid species in relation to sensitivity to environmental pollutants
           
    • Authors: Peter van den Hurk; Lindsay E. Gerzel; Peter Calomiris; Dennis C. Haney
      Pages: 20 - 25
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Peter van den Hurk, Lindsay E. Gerzel, Peter Calomiris, Dennis C. Haney
      Observations in a previous study on biomarker responses in fish collected from urban creeks in Greenville, SC, indicated that there might be considerable differences in the expression of biotransformation enzymes in chub and sunfish species. To further investigate these species differences a dosing experiment was performed in which bluehead and creek chub (Nocomis leptocephalus and Semotilus atromaculatus), and redbreast sunfish, pumpkinseed, and bluegill (Lepomis auritus, L. gibbosus, and L. macrochirus) were injected with benzo[a]pyrene (BaP) as a model compound for common pollutants in urban creeks. Fish were injected with BaP doses of 0, 25 and 50mg/kg, and after 3days BaP metabolites in bile, and enzymatic activities of cytochrome P450-1A (CYP1A), UDP-glucuronosyltransferase (UGT) and glutathione S-transferase (GST) were measured. CYP1A activity was significantly increased after BaP dosing in both species groups, but chubs had significantly lower levels than were observed in the dosed sunfish. The UGT activity in unexposed animals was comparable in both species groups, and significantly increased in both groups as a result of BaP dosage. Finally, GST activity was significantly higher in chubs, but did not change in either species group as a result of BaP exposure. There were no significant differences between species within each species group, and the results confirmed that unexposed chubs have much lower CYP1A activity, but a much higher GST activity than unexposed sunfish. The metabolized BaP was excreted in both species groups, but at the time of sampling there were no differences in the amount of BaP metabolites in the bile of dosed animals. The differences in baseline enzyme activity and induction capacity between both species groups are an example of phylogenetically determined differences between fish families, and may explain why chubs are in general more sensitive to exposure to environmental pollutants than sunfish. This conclusion was corroborated by the observation that the highest BaP dose of 50mg/kg was close to the apparent LC50 for chub, while no mortality was observed in the sunfish at this dose.

      PubDate: 2017-04-29T08:14:24Z
      DOI: 10.1016/j.aquatox.2017.04.004
      Issue No: Vol. 188 (2017)
       
  • Immunosuppressive effects and associated compensatory responses in
           zebrafish after full life-cycle exposure to environmentally relevant
           concentrations of cadmium
    • Authors: Sai-Nan Guo; Jia-Lang Zheng; Shuang-Shuang Yuan; Qing-Ling Zhu; Chang-Wen Wu
      Pages: 64 - 71
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Sai-Nan Guo, Jia-Lang Zheng, Shuang-Shuang Yuan, Qing-Ling Zhu, Chang-Wen Wu
      In natural environments, fish survive in polluted water by cadmium (Cd) throughout their whole life cycle. However, little information is available on Cd toxicity considering a life cycle assessment. The present study investigated effects of environmental levels of cadmium (0, 2.5, and 5μg/L) on immune responses in liver and spleen of zebrafish for 15 weeks, from embryos to sexually maturity. Nitric oxide (NO) levels and iNOS activity declined in liver and spleen of zebrafish exposed to 5μg/L Cd, suggesting an immunosuppressive effect. The result was further supported by the decreased transcriptional levels of proinflammatory cytokines by Cd, such as interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1β (IL-1β), and tumour necrosis factor-α (TNF-α) in liver. However, a sharp increase in the mRNA levels of these cytokines was observed in spleen of zebrafish exposed to Cd. The increased mRNA expression of these proinflammatory cytokines may be the secondary effect following immunosuppression and just reflect a compensatory mechanism for coping with the decreased immunity, which may explain an increase in mRNA levels and a decrease in iNOS activity in spleen of zebrafish exposed to Cd. In liver, the down-regulated mRNA levels of iNOS paralleled with the decreased iNOS activity, suggesting a synchronous response from a molecular level to a biochemical level. Positive correlations between mRNA expression levels of nuclear transcription factor κB (NF-κB) and proinflammatory cytokines were also observed, suggesting that NF-κB might be required for the protracted induction of inflammatory genes. The corresponding changes in the mRNA levels of the inhibitor of κBα (IκBαa and IκBαb) may form a feedback loop to restore transcriptional activity of NF-κB. Furthermore, splenic ROS levels were increased by 5μg/L Cd, possibly activating NF-κB pathway. Taken together, immunosuppressive effects and tissue-dependent compensatory responses were demonstrated in zebrafish after full life-cycle exposure to environmental levels of Cd, indicating a compromise between survival and immunity.

      PubDate: 2017-04-29T08:14:24Z
      DOI: 10.1016/j.aquatox.2017.04.014
      Issue No: Vol. 188 (2017)
       
  • Acute toxicity and esterase response to carbaryl exposure in two different
           populations of amphipods Hyalella curvispina
    • Authors: Olga Liliana Anguiano; Melina Vacca; María Emilia Rodriguez Araujo; Mónica Montagna; Andrés Venturino; Ana Ferrari
      Pages: 72 - 79
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Olga Liliana Anguiano, Melina Vacca, María Emilia Rodriguez Araujo, Mónica Montagna, Andrés Venturino, Ana Ferrari
      During the last years, a carbaryl insecticide was extensively applied in the valley of Río Negro and Neuquén, North Patagonia Argentina, to manage codling moths (Cydia pomonella), the main pest of pear and apple trees. In this study carbaryl susceptibility and B-esterase activity from both insecticide-exposed and non-exposed field populations of amphipods Hyalella curvispina were studied. Two subpopulations, one susceptible to carbaryl (LC50 =213±7.5μg/L carbaryl) and one resistant to it (LC50 =14,663±2379μg/L carbaryl), were found in the agricultural area selected in this study. Both populations were, in turn, more resistant to carbaryl than the population from a pristine area (LC50 =11.31±2.27μg/L carbaryl). The in vivo 48h-IC50 values for cholinesterase (ChE) were close to the corresponding 48h-LC50 values as determined for the non-exposed population (IC50 =7.16±0.86μg/L carbaryl) and for the susceptible subpopulation from the insecticide-exposed site (IC50 =193±99μg/L carbaryl). Carbaryl exposure of the amphipods from the agricultural area mentioned above produced a significant decrease of carboxylesterase (CabE) activity, at a sublethal concentration (10μg/L) that was not able to significantly inhibit ChE, thereby showing a protective role of CabE and its usefulness as early biomarker. However, at lethal concentrations the inhibition of ChE activity was higher than that of CabE. On the other hand, CabE of amphipods from the pristine site was less sensitive to carbaryl than ChE, suggesting a different participation of CabE in ChE protection in the susceptible population of H. curvispina. Pulse exposure to carbaryl for 2h caused a significant inhibition of ChE in amphipods from both populations, with a fast recovery as expected for a carbamate insecticide. In conclusion, we proved that amphipods from the said agricultural area have developed resistance to carbaryl and showed the presence of two subpopulations with a different response to the insecticide. Moreover, these results reinforce the use of ChE together with CabE inhibition as indicators of carbamate exposure in H. curvispina.

      PubDate: 2017-05-05T07:13:28Z
      DOI: 10.1016/j.aquatox.2017.04.013
      Issue No: Vol. 188 (2017)
       
  • Modifications of the soluble proteome of a mediterranean strain of the
           invasive neurotoxic dinoflagellate Alexandrium catenella under metal
           stress conditions
    • Authors: Natacha Jean; Estelle Dumont; Faouzi Herzi; Thierry Balliau; Mohamed Laabir; Estelle Masseret; Stéphane Mounier
      Pages: 80 - 91
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Natacha Jean, Estelle Dumont, Faouzi Herzi, Thierry Balliau, Mohamed Laabir, Estelle Masseret, Stéphane Mounier
      The soluble proteome of the mediterranean strain ACT03 of the invasive neurotoxic dinoflagellate Alexandrium catenella exposed to lead or zinc at 6, 12 or 18μM (total concentrations), or under control conditions, was characterized by two-dimensional gel electrophoresis (2-DE). Zinc reduced (P<0.05) the total number of protein spots (−41%, −52% and −60%, at 6, 12 or 18μM, respectively). Besides, most of the proteins constituting the soluble proteome were down-regulated in response to lead or zinc stresses. These proteins were involved mainly in photosynthesis (20–37% for lead; 36–50% for zinc) (ribulose-1,5-bisphosphate carboxylase/oxygenase: RUBISCO; ferredoxin-NADP+ reductase: FNR; peridinin-chlorophyll a-protein: PCP), and in the oxidative stress response (29–34% for lead; 17–36% for zinc) (superoxide dismutase: SOD; proteasome α/β subunits). These negative effects could be partly compensated by the up-regulation of specific proteins such as ATP-synthase β subunit (+16.3 fold after exposure to lead at 12μM). Indeed, an increase in the abundance of ATP-synthase could enrich the ATP pool and provide more energy available for the cells to survive under metal stress, and make the ATP-synthase transport of metal cations out of the cells more efficient. Finally, this study shows that exposure to lead or zinc have a harmful effect on the soluble proteome of A. catenella ACT03, but also suggests the existence of an adaptative proteomic response to metal stresses, which could contribute to maintaining the development of this dinoflagellate in trace metal-contaminated ecosystems.

      PubDate: 2017-05-05T07:13:28Z
      DOI: 10.1016/j.aquatox.2017.04.011
      Issue No: Vol. 188 (2017)
       
  • Characterization of cadmium transport in hepatopancreatic cells of a
           mangrove crab Ucides cordatus: The role of calcium
    • Authors: Priscila Ortega; Marcio R. Custódio; Flavia P. Zanotto
      Pages: 92 - 99
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Priscila Ortega, Marcio R. Custódio, Flavia P. Zanotto
      Cadmium is a toxic metal, present in batteries and discarded in estuaries and mangrove habitats. Apart from that, it is a non-essential metal that causes toxic effects in many organisms. Cadmium accumulates in gills and hepatopancreas of crustaceans and its route into the cell is unknown. It is possible that occurs by calcium channels or calcium transporters. The objective of this study was to characterize the transport of cadmium and the role of calcium in different cell types from hepatopancreas of the mangrove crab Ucides cordatus. For this, the hepatopancreas was dissociated by magnetic stirring and after that separated by a sucrose gradient. Then, the cells were labeled with FluoZin-3 AM and different CdCl2 concentrations were added together with a variety of inhibitors. The results showed that Cd2+ transport occurs differently in each cell type from hepatopancreas and is partially explained by the function the cells perform in this organ. Embryonic (E) and Resorptive (R) cells transported more Cd2+ compared to Fibrillar (F) and Blister (B) cells. R cells responded to Ca2+ channel inhibitors and intracellular Ca2+ manipulations positively, as the other cell types and in a stronger way. B cells were the least responsive to Ca2+ channel inhibitors and, unlike the other cells, showed a competition of Cd2+ with intracellular Ca2+ manipulations. The results indicate that Ca2+ affects the transport of Cd2+ in hepatopancreatic cells of Ucides cordatus and uses Ca2+ channels to enter these cells. In addition, information about Ca concentration could be used as a mitigating factor for Cd accumulation in crabs’ hepatopancreas.

      PubDate: 2017-05-05T07:13:28Z
      DOI: 10.1016/j.aquatox.2017.04.012
      Issue No: Vol. 188 (2017)
       
  • Green-synthesized CdS nano-pesticides: Toxicity on young instars of
           malaria vectors and impact on enzymatic activities of the non-target mud
           crab Scylla serrata
    • Authors: Vasu Sujitha; Kadarkarai Murugan; Devakumar Dinesh; Amuthvalli Pandiyan; Rajasekar Aruliah; Jiang-Shiou Hwang; Kandasamy Kalimuthu; Chellasamy Panneerselvam; Akon Higuchi; Al Thabiani Aziz; Suresh Kumar; Abdullah A. Alarfaj; Baskaralingam Vaseeharan; Angelo Canale; Giovanni Benelli
      Pages: 100 - 108
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Vasu Sujitha, Kadarkarai Murugan, Devakumar Dinesh, Amuthvalli Pandiyan, Rajasekar Aruliah, Jiang-Shiou Hwang, Kandasamy Kalimuthu, Chellasamy Panneerselvam, Akon Higuchi, Al Thabiani Aziz, Suresh Kumar, Abdullah A. Alarfaj, Baskaralingam Vaseeharan, Angelo Canale, Giovanni Benelli
      Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensi and A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparum parasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV–vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC50 of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of V. pachynema extract was 58.1μg/ml (CQ-s) and 71.46μg/ml (CQ-r), while nano-CdS IC50 was 76.14μg/ml (CQ-s) and 89.21μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of CdS nanoparticles and Cd ions in aqueous solution was also assessed in mud crabs, showing higher toxicity of aqueous Cd ions if compared to nano-CdS. Overall, our results underlined the efficacy of green-synthesized CdS nanoparticles in malaria vector control, outlining also significant impacts on the enzymatic activity of non-target aquatic organisms, with special reference to mud crabs.

      PubDate: 2017-05-10T07:18:26Z
      DOI: 10.1016/j.aquatox.2017.04.015
      Issue No: Vol. 188 (2017)
       
  • RNA-sequencing and pathway analysis reveal alteration of hepatic steroid
           biosynthesis and retinol metabolism by tributyltin exposure in male rare
           minnow (Gobiocypris rarus)
    • Authors: Jiliang Zhang; Chunnuan Zhang; Ping Sun; Maoxian Huang; Mingzhen Fan; Min Liu
      Pages: 109 - 118
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Jiliang Zhang, Chunnuan Zhang, Ping Sun, Maoxian Huang, Mingzhen Fan, Min Liu
      Tributyltin (TBT) is widely spread in aquatic ecosystems. Although adverse effects of TBT on reproduction and lipogenesis are observed in fishes, the underlying mechanisms, especially in livers, are still scarce and inconclusive. Thus, RNA-sequencing runs were performed on the hepatic libraries of adult male rare minnow (Gobiocypris rarus) after TBT exposure for 60d. After differentially expressed genes were identified, enrichment analysis and validation by quantitative real-time PCR were conducted. The results showed that TBT up-regulated the profile of hepatic genes in the steroid biosynthesis pathway and down-regulated the profile of hepatic genes in the retinol metabolism pathway. In the hepatic steroid biosynthesis pathway, TBT might induce biosynthesis of cholesterol, which could affect the bioavailability of steroid hormones. More important, 3beta-hydroxysteroid 3-dehydrogenase, a key enzyme in the biosynthesis of all active steroid hormones, was up-regulated by TBT exposure. In the hepatic retinol metabolism pathway, TBT impaired retinoic acid homeostasis which plays essential roles in both reproduction and lipogenesis. The results of two pathways offered new mechanisms underlying the toxicology of TBT and represented a starting point from which detailed mechanistic links should be explored.

      PubDate: 2017-05-14T21:19:45Z
      DOI: 10.1016/j.aquatox.2017.03.015
      Issue No: Vol. 188 (2017)
       
  • Intracellular localization and toxicity of graphene oxide and reduced
           graphene oxide nanoplatelets to mussel hemocytes in vitro
    • Authors: Alberto Katsumiti; Radmila Tomovska; Miren P. Cajaraville
      Pages: 138 - 147
      Abstract: Publication date: July 2017
      Source:Aquatic Toxicology, Volume 188
      Author(s): Alberto Katsumiti, Radmila Tomovska, Miren P. Cajaraville
      Recently, graphene materials have attracted tremendous research interest due to their unique physicochemical properties that hold great promise in electronics, energy, materials and biomedical areas. Graphene oxide (GO) is one of the most extensively studied graphene derivatives. In order to improve GO electrical properties, nanoplatelets are chemically reduced, thus increasing nanoplatelet conductivity. This reduced GO (rGO) shows different properties and behavior compared to GO. Graphene-based wastes are expected to end up in the marine environment. Here we aimed to assess the potential toxic effects of GO and rGO to marine organisms by using in vitro assays with mussel (Mytilus galloprovincialis) hemocytes. Cells were exposed to a wide range of concentrations (up to 100mg/L) of GO (with and without polyvinylpyrrolidone-PVP as stabilizing agent: GO and GO-PVP) and rGO with PVP (rGO-PVP) to assess cytotoxicity and cell membrane integrity. Then, cells were exposed to sublethal concentrations of GO and rGO-PVP to assess their subcellular distribution through transmission electron microscopy (TEM) and to evaluate their effects on ROS production. GO, GO-PVP and rGO-PVP showed low and concentration-dependent cytotoxicity. rGO-PVP (LC50=29.902 and 33.94mg/L depending on the origin) was more toxic than GO (LC50=49.84 and 54.51mg/L depending on the origin) and GO-PVP (LC50=43.72mg/L). PVP was not toxic to hemocytes but increased bioavailability and toxicity of nanoplatelets. At TEM, GO and rGO-PVP nanoplatelets caused invaginations and perforations of the plasma membrane, which agrees with the observed decrease in cell membrane integrity. Nanoplatelets were internalized, at a higher extent for rGO-PVP than for GO, and found in the cytosol and in endolysosomal vesicles of hemocytes. Both GO and rGO-PVP increased ROS production at the highest sublethal concentration tested. In conclusion, GO, GO-PVP and rGO-PVP are not highly toxic to mussel cells but they cause membrane damage and their toxicity is ROS-mediated. Finally, in vitro assays with mussel hemocytes are sensitive tools to detect toxic effects of graphene-based nanomaterials.
      Graphical abstract image

      PubDate: 2017-05-19T21:21:24Z
      DOI: 10.1016/j.aquatox.2017.04.016
      Issue No: Vol. 188 (2017)
       
  • Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck
           (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen
           conditions
    • Authors: Suleiman Dauda; Mathias Ahii Chia; Sunday Paul Bako
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Suleiman Dauda, Mathias Ahii Chia, Sunday Paul Bako
      The broad application of titanium dioxide nanoparticles (n-TiO2) in many consumer products has resulted in the release of substantial quantities into aquatic systems. While n-TiO2 have been shown to induce some unexpected toxic effects on aquatic organisms such as microalgae, the influence of changing nutrient conditions on the toxicity of the metal has not been investigated. We evaluated the toxicity of n-TiO2 to Chlorella vulgaris under varying nitrogen conditions. Limited nitrogen (2.2μM) decreased growth and biomass (dry weight and pigment content), while lipid peroxidation (malondialdehyde content), glutathione S-transferase activity (GST) and peroxidase (POD) activity were increased. Similarly, exposure to n-TiO2 under replete nitrogen condition resulted in a general decrease in growth and biomass, while GST and POD activities were significantly increased. The combination of limited nitrogen with n-TiO2 exposure further decreased growth and biomass, and increased GST and POD activities of the microalga. These results suggest that in addition to the individual effects of each investigated condition, nitrogen limitation makes C. vulgaris more susceptible to the effects of n-TiO2 with regard to some physiological parameters. This implies that the exposure of C. vulgaris and possibly other green algae to this nanoparticle under limited or low nitrogen conditions may negatively affect their contribution to primary production in oligotrophic aquatic ecosystems.

      PubDate: 2017-04-15T08:03:32Z
      DOI: 10.1016/j.aquatox.2017.03.020
      Issue No: Vol. 187 (2017)
       
  • Different transcriptomic responses of two marine copepods, Tigriopus
           japonicus and Pseudodiaptomus annandalei, to a low dose of mercury
           chloride (HgCl2)
    • Authors: Minghua Wang; Chang-Bum Jeong; Yan Li; Jae-Seong Lee
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Minghua Wang, Chang-Bum Jeong, Yan Li, Jae-Seong Lee
      Mercury (Hg) pollution is a ubiquitous and serious concern in marine environments, but the response mechanisms of marine animals to Hg pollution (i.e., toxicity/tolerance) are poorly understood. To compare the global responses of two marine copepods (Tigriopus japonicus and Pseudodiaptomus annandalei), we analyzed whole transcriptomes using RNA-seq technology in response to Hg treatment (a nominal 10μg/L HgCl2 in seawater) for 5h. Hg was strikingly accumulated in both copepods under treatment. The Hg concentration in P. annandalei was higher under metal exposure by approximately 1.4-fold compared with treated T. japonicus. Among transcriptomic data, 101 genes in T. japonicus and 18 genes in P. annandalei were differentially regulated in response to Hg exposure. The up-regulated genes in T. japonicus were concerned with stress, growth, and development, while the down-regulated ones were mainly related to immune response. In P. annandalei, most of the differentially expressed genes were up-regulated, and all were involved in stress response. Our work indicated that Hg exhibits endocrine-disrupting potential at the transcriptomic level in marine copepods. Overall, our study demonstrates the species-specific molecular responses of these two copepods to Hg pollution.

      PubDate: 2017-04-15T08:03:32Z
      DOI: 10.1016/j.aquatox.2017.03.018
      Issue No: Vol. 187 (2017)
       
  • Nine co-localized cytochrome P450 genes of the CYP2N, CYP2AD, and CYP2P
           gene families in the mangrove killifish Kryptolebias marmoratus genome:
           Identification and expression in response to B[α]P, BPA, OP, and NP
    • Authors: Jayesh Puthumana; Bo-Mi Kim; Chang-Bum Jeong; Duck-Hyun Kim; Hye-Min Kang; Jee-Hyun Jung; Il-Chan Kim; Un-Ki Hwang; Jae-Seong Lee
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Jayesh Puthumana, Bo-Mi Kim, Chang-Bum Jeong, Duck-Hyun Kim, Hye-Min Kang, Jee-Hyun Jung, Il-Chan Kim, Un-Ki Hwang, Jae-Seong Lee
      The CYP2 genes are the largest and most diverse cytochrome P450 (CYP) subfamily in vertebrates. We have identified nine co-localized CYP2 genes (∼55kb) in a new cluster in the genome of the highly resilient ecotoxicological fish model Kryptolebias marmoratus. Molecular characterization, temporal and tissue-specific expression pattern, and response to xenobiotics of these genes were examined. The CYP2 gene clusters were characterized and designated CYP2N22-23, CYP2AD12, and CYP2P16-20. Gene synteny analysis confirmed that the cluster in K. marmoratus is similar to that found in other teleost fishes, including zebrafish. A gene duplication event with diverged catalytic function was observed in CYP2AD12. Moreover, a high level of divergence in expression was observed among the co-localized genes. Phylogeny of the cluster suggested an orthologous relationship with similar genes in zebrafish and Japanese medaka. Gene expression analysis showed that CYP2P19 and CYP2N20 were consecutively expressed throughout embryonic development, whereas CYP2P18 was expressed in all adult tissues, suggesting that members of each CYP2 gene family have different physiological roles even though they are located in the same cluster. Among endocrine-disrupting chemicals (EDCs), benzo[α]pyrene (B[α]P) induced expression of CYP2N23, bisphenol A (BPA) induced CYP2P18 and CYP2P19, and 4-octylphenol (OP) induced CYP2AD12, but there was no significant response to 4-nonylphenol (NP), implying differential catalytic roles of the enzyme. In this paper, we identify and characterize a CYP2 gene cluster in the mangrove killifish K. marmoratus with differing catalytic roles toward EDCs. Our findings provide insights on the roles of nine co-localized CYP2 genes and their catalytic functions for better understanding of chemical-biological interactions in fish.

      PubDate: 2017-04-15T08:03:32Z
      DOI: 10.1016/j.aquatox.2017.03.022
      Issue No: Vol. 187 (2017)
       
  • Tissue uptake, distribution and excretion of brevetoxin-3 after oral and
           intratracheal exposure in the freshwater turtle Trachemys scripta and the
           diamondback terrapin Malaclemys terrapin
    • Authors: Courtney C. Cocilova; Leanne J. Flewelling; Gregory D. Bossart; April A. Granholm; Sarah L. Milton
      Pages: 29 - 37
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Courtney C. Cocilova, Leanne J. Flewelling, Gregory D. Bossart, April A. Granholm, Sarah L. Milton
      Harmful algal blooms (HABs) occur nearly annually off the west coast of Florida and can impact both humans and wildlife, resulting in morbidity and increased mortality of marine animals including sea turtles. The key organism in Florida red tides is the dinoflagellate Karenia brevis that produces a suite of potent neurotoxins referred to as the brevetoxins (PbTx). Despite recent mortality events and rehabilitation efforts, still little is known about how the toxin directly impacts sea turtles, as they are not amenable to experimentation and what is known about toxin levels and distribution comes primarily from post-mortem data. In this study, we utilized the freshwater turtle Trachemys scripta and the diamondback terrapin, Malaclemys terrapin as model organisms to determine the distribution, clearance, and routes of excretion of the most common form of the toxin, brevetoxin-3, in turtles. Turtles were administered toxin via esophageal tube to mimic ingestion (33.48μg/kg PbTx-3, 3×/week for two weeks for a total of 7 doses) or by intratracheal instillation (10.53μg/kg, 3×/week for four weeks for a total of 12 doses) to mimic inhalation. Both oral and intratracheal administration of the toxin produced a suite of behavioral responses symptomatic of brevetoxicosis. The toxin distributed to all organ systems within 1h of administration but was rapidly cleared out over 24–48h, corresponding to a decline in clinical symptoms. Excretion appears to be primarily through conjugation to bile salts. Histopathological study revealed that the frequency of lesions varied within experimental groups with some turtles having no significant lesions at all, while similar lesions were found in a low number of control turtles suggesting another common factor(s) could be responsible. The overall goal of this research is better understand the impacts of brevetoxin on turtles in order to develop better treatment protocols for sea turtles exposed to HABs.

      PubDate: 2017-04-02T11:58:17Z
      DOI: 10.1016/j.aquatox.2017.03.003
      Issue No: Vol. 187 (2017)
       
  • Age-dependent changes in sensitivity to a pesticide in tadpoles of the
           common toad (Bufo bufo)
    • Authors: Zsanett Mikó; János Ujszegi; Attila Hettyey
      Pages: 48 - 54
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Zsanett Mikó, János Ujszegi, Attila Hettyey
      The worldwide en masse application of pesticides and the frequently reported malign effects on several non-target organisms underpin the importance of ecotoxicological research on these anthropogenic pollutants. Previous studies showed that sensitivity to herbicides can vary widely depending on additional stress factors, on the species and even on the population investigated. However, there is little information about how sensitivity changes during ontogeny, and how the duration of exposure is linked to the magnitude of malign effects, even though this knowledge would be important for the interpretation of toxicity test results and for formulating recommendations regarding the timing of pesticide application. We exposed tadpoles of the common toad (Bufo bufo) to three concentrations (0, 2 and 4mg a.e./L) of a glyphosate-based herbicide during the 1st, 2nd, 3rd, 4th, or 5th period of larval development or during the entire experiment, and measured survival, time until metamorphosis and body mass at metamorphosis to estimate fitness-consequences. Younger tadpoles were more sensitive to the herbicide in all measured traits than older ones, and this age-dependence was especially pronounced at the high herbicide concentration. Furthermore, tadpoles exposed to the herbicide during the entire experiment developed slower than tadpoles exposed only early on, but we did not observe a similar effect either on body mass or survival. The observed age-dependence of sensitivity to herbicides draws attention to the fact that results of toxicity tests obtained for one age-class are not necessarily generalizable across ontogeny. Also, the age of test animals has to be considered when planning ecotoxicological studies and interpreting their results. Finally, taking into account the temporal breeding habits of local amphibians when planning pesticide application would be highly favourable: if tadpoles would not get exposed to the herbicide during their most sensitive early development, they would sustain less anthropogenic damage from our efforts of controlling weeds.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.03.016
      Issue No: Vol. 187 (2017)
       
  • The ROS-mediated pathway coupled with the MAPK-p38 signalling pathway and
           antioxidant system plays roles in the responses of Mytilus edulis
           haemocytes induced by BDE-47
    • Authors: Yongshun Jiang; Xuexi Tang; Bin Zhou; Tianli Sun; Hongmei Chen; Xinyu Zhao; You Wang
      Pages: 55 - 63
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Yongshun Jiang, Xuexi Tang, Bin Zhou, Tianli Sun, Hongmei Chen, Xinyu Zhao, You Wang
      Our previous study found that BDE-47 could change the immune function of haemocytes in Mytilus edulis, and reactive oxygen species (ROS) might be involved in the process of physiological alteration. Here, we aimed to better understand this relationship. To accomplish this, we analysed changes in different ROS as well as various antioxidant system components. Additionally, the expression of MAPK-p38, a signalling protein regulated by ROS that helps to regulate numerous cellular processes, was also analysed. BDE-47 was given at low, medium, and high amounts. The results showed that (1) BDE-47 significantly affected ROS component levels in haemocytes. O 2 − content was increased under all conditions. H2O2 content was also increased under all conditions, except in the middle concentration group. In contrast, OH content was increased in the low and middle concentration groups and decreased in the high concentration group. (2) Estimations of the antioxidant systems revealed concentration-dependent changes. Catalase activity was increased throughout the experiment, while superoxide dismutase (SOD) exhibited a decreasing trend in the tested groups with an increase of exposure time. On day 21, only the high concentration group showed a slight increase in SOD activity compared to the control. Furthermore, glutathione peroxidase and glutathione reductase activity increased in the low and middle concentration groups but decreased in the high concentration group. The GSH/GSSG ratio increased for all treatments over time, indicating that changes in redox status occurred. (3) MAPK-p38 was activated following BDE-47 exposure. Based on our previous study, we speculate that BDE-47 exposure induces ROS production and affects the ROS-mediated pathway, which may explain the resultant functional damage observed in haemocytes. Furthermore, BDE-47 also affected the antioxidant system and altered redox status, although these changes did not ameliorate the damage caused by ROS.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.03.011
      Issue No: Vol. 187 (2017)
       
  • Biomarker response and hypothalamus-pituitary-interrenal axis functioning
           in Arctic charr from Bjørnøya (74°30′ N), Norway, with high levels
           of organohalogenated compounds
    • Authors: Even H. Jørgensen; Alec G. Maule; Anita Evenset; Guttorm Christensen; Jenny Bytningsvik; Marianne Frantzen; Vladimir Nikiforov; Erin Faught; Mathilakath M. Vijayan
      Pages: 64 - 71
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Even H. Jørgensen, Alec G. Maule, Anita Evenset, Guttorm Christensen, Jenny Bytningsvik, Marianne Frantzen, Vladimir Nikiforov, Erin Faught, Mathilakath M. Vijayan
      The populations of Arctic charr (Salvelinus alpinus) residing in Lake Ellasjøen at Bjørnøya Island in the Norwegian Arctic (74° 30′N, 19° 00′E) possess substantially higher levels of organohalogenated compounds (strongly dominated by polychlorinated biphenyls, PCBs) than conspecifics residing in other, proximate lakes on the island. In the present study we sampled large (<400g), immature charr from Lake Ellasjøen (high PCB levels) and Lake Laksvatn (reference lake, low PCB levels) by hook and line for an immediate blood sampling, and blood and tissue sampling after a 1h confinement stressor. This was done in order to investigate possible effects of pollutants on an acute stress performance in a high-latitude fish species by comparing muscle PCB levels, hepatic cytochrome P4501A (CYP1A) biomarker activation and functioning of the hypothalamus-pituitary-interrenal (HPI) axis between these two populations of Arctic charr. As expected sum PCB muscle levels were 8-fold higher on a wet weigh basis, and 19-fold higher on a lipid weight basis, in charr from Ellasjøen than in charr from Laksvatn. This was accompanied by a 3.5-fold higher liver cyp1a mRNA abundance in the Ellasjøen charr compared to Laksvatn charr. Brain transcript levels encoding glucocorticoid receptor 1 and 2 (GR2) and corticotropin-releasing factor, and pituitary transcript levels encoding GR2 and proopiomelanocortin A1 and A2 were higher in Ellasjøen charr than in Laksvatn charr, while interrenal transcript levels encoding melanocortin 2 receptor and steroidogenic acute regulatory protein were lower. There were no differences in plasma cortisol concentration between the two charr populations immediately after capture and one hour after confinement. The strong biomarker response to OHCs and altered mRNA abundances of key genes related to HPI axis functioning in the Ellasjøen charr suggest endocrine disruptive effects of OHCs in this charr population. Possible ecological implications are not known, but it cannot be excluded that a slower growth rate in Ellasjøen charr compared to Laksvatn charr due to an increased metabolic demand associated with the activation of xenobiotic defense and detoxification systems may have contributed to the lower body mass of Ellasjøen charr compared to Laksvatn charr.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.03.017
      Issue No: Vol. 187 (2017)
       
  • Sustained impairment of respiratory function and swim performance
           following acute oil exposure in a coastal marine fish
    • Authors: J.L. Johansen; A.J. Esbaugh
      Pages: 82 - 89
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): J.L. Johansen, A.J. Esbaugh
      Acute exposure to crude oil polycyclic aromatic hydrocarbons (PAH) can severely impair cardiorespiratory function and swim performance of larval fish; however, the effects of acute oil exposure on later life stages and the capacity for subsequent recovery is less clear. Red drum (Sciaenops ocellatus) is an economically important apex predator native to the Gulf of Mexico, which was directly exposed to the 2010 Deep Water Horizon (DWH) oil spill. Here we examine impact and recovery of young adult red drum from exposure to concentrations of 0, 4.1, and 12.1μgL−1 ΣPAH50 naturally weathered oil-water accommodated fractions (geometric mean), which are well within the range of concentrations measured during the DWH incident. We focused on aerobic scope (ASc), burst- and critical swimming speeds (Uburst and Ucrit), cost of transport (COT), as well as the capacity to repay oxygen debt following exhaustive exercise (EPOC), which are critical parameters for success of all life stages of fishes. A 24h acute exposure to 4.1μgL−1 ΣPAH caused a significant 9.7 and 12.6% reduction of Uburst and Ucrit respectively, but no change in ASc, COT or EPOC, highlighting a decoupled effect on the respiratory and swimming systems. A higher exposure concentration, 12.1μgL−1 ΣPAH, caused an 8.6 and 8.4% impairment of Uburst and Ucrit, as well as an 18.4% reduction in ASc. These impairments persisted six weeks post-exposure, suggesting that recorded impacts are entrenched. Large predatory fishes are critically dependent on the cardiorespiratory and swimming systems for ecological fitness, and long-term impairment of performance due to acute oil exposure suggests that even acute exposure events may have long lasting impacts on the ecological fitness of affected populations.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.04.002
      Issue No: Vol. 187 (2017)
       
  • Acute toxication of deltamethrin results in activation of iNOS, 8-OHdG and
           up-regulation of caspase 3, iNOS gene expression in common carp (Cyprinus
           carpio L.)
    • Authors: Harun Arslan; Serdar Altun; Selçuk Özdemir
      Pages: 90 - 99
      Abstract: Publication date: Available online 2 April 2017
      Source:Aquatic Toxicology
      Author(s): Harun Arslan, Serdar Altun, Selçuk Özdemir
      Deltamethrin is a widely used synthetic pyrethroid pesticide that protects agricultural yields, including crops, fruits, and vegetables from insect-pests. It is known that deltamethrin toxication leads to metabolic disorders and has detrimental effects on the brain and liver in different organisms. However, the harmful effects of deltamethrin toxication on aquatic animals remain unclear. In the present study, we aimed to evaluate the adverse effects of deltamethrin toxication by performing a histopathological examination, an immunofluorescence assay, and a qRT-PCR on common carp. We observed that a low-dose (0.04μM) and a high-dose (0.08μM) of deltamethrin exposure caused lamellar cells hyperplasia and inflammatory cells infiltration in the gills, hyperemia, diffuse hydropic degenerations and focal necrosis in the hepatocytes, necrotic changes in the neurons, and also induced activation of inducible Nitric Oxide Synthase (iNOS) and 8-hydroxy-2-deoxyguanosine (8-OHdG) in the gills, liver, and brain depending on the exposure time (24h, 48h, 72h and 96h). In addition, deltamethrin toxication caused the up-regulation of caspase-3 and the inducible Nitric Oxide Synthase (iNOS) of the gene expression depending on the dose (0.04μM and 0.08μM) and the exposure time in the brain (p< 0.05, p< 0.01, p< 0.001). Our results indicated that long-term deltamethrin exposure could lead to inflammation, oxidative stress, DNA damage, and apoptosis on the different organs in common carp. Thus, deltamethrin toxication is dangerous for common carp populations, and the usage of deltamethrin should be controlled and restricted in agricultural areas.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.03.014
      Issue No: Vol. 187 (2017)
       
  • Effects of cyanobacteria Synechocystis spp. in the host-parasite model
           Crassostrea gasar–Perkinsus marinus
    • Authors: Fernando Ramos Queiroga; Luis Fernando Marques-Santos; Hélène Hégaret; Roberto Sassi; Natanael Dantas Farias; Lucas Nunes Santana; Patricia Mirella da Silva
      Pages: 100 - 107
      Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187
      Author(s): Fernando Ramos Queiroga, Luis Fernando Marques-Santos, Hélène Hégaret, Roberto Sassi, Natanael Dantas Farias, Lucas Nunes Santana, Patricia Mirella da Silva
      Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4h) and long (48h and 7days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of cyanobacteria; while neither the WCs nor the ECPs modified phagocytosis of the biological particles, zymosan and P. marinus. Our results suggest a negative effect of cyanobacteria from the Synechocystis genus on host immune cells, in contrast to a more beneficial effect on the parasite cell, which could together disrupt the balance of the host-parasite interaction and make oysters more susceptible to P. marinus as well as opportunistic infections.

      PubDate: 2017-04-15T08:03:32Z
      DOI: 10.1016/j.aquatox.2017.03.019
      Issue No: Vol. 187 (2017)
       
  • Embryonic-only arsenic exposure in killifish (Fundulus heteroclitus)
           reduces growth and alters muscle IGF levels one year later
    • Authors: Dana B. Szymkowicz; Kaleigh C. Sims; Noemi M. Castro; William C. Bridges; Lisa J. Bain
      Pages: 1 - 10
      Abstract: Publication date: May 2017
      Source:Aquatic Toxicology, Volume 186
      Author(s): Dana B. Szymkowicz, Kaleigh C. Sims, Noemi M. Castro, William C. Bridges, Lisa J. Bain
      Arsenic is a contaminant of drinking water and crops in many parts of the world. Epidemiological studies have shown that arsenic exposure is linked to decreased birth weight, weight gain, and proper skeletal muscle function. The goal of this study was to use killifish (Fundulus heteroclitus) as a model to determine the long-term effects of embryonic-only arsenic exposure on muscle growth and the insulin-like growth factor (IGF) pathway. Killifish embryos were exposed to 0, 50, 200 or 800ppb AsIII from fertilization until hatching. Juvenile fish were reared in clean water and muscle samples were collected at 16, 28, 40 and 52 weeks of age. There were significant reductions in condition factors, ranging from 12 to 17%, in the fish exposed to arsenic at 16, 28 and 40 weeks of age. However, by 52 weeks, no significant changes in condition factors were seen. Alterations in IGF-1R and IGF-1 levels were assessed as a potential mechanism by which growth was reduced. While there no changes in hepatic IGF-1 transcripts, skeletal muscle cells can also produce their own IGF-1 and/or alter IGF-1 receptor levels to help enhance growth. After a 200 and 800ppb embryonic exposure, fish grown in clean water for 16 weeks had IGF-1R transcripts that were 2.8-fold and 2-fold greater, respectively, than unexposed fish. Through 40 weeks of age, IGF1-R remained elevated in the 200ppb and 800ppb embryonic exposure groups by 1.8–3.9-fold, while at 52 weeks of age, IGF-1R levels were still significantly increased in the 800ppb exposure group. Skeletal muscle IGF-1 transcripts were also significantly increased by 1.9–5.1 fold through the 52 weeks of grow-out in clean by water in the 800ppb embryonic exposure group. Based on these results, embryonic arsenic exposure has long-term effects in that it reduces growth and increases both IGF-1 and IGF-1R levels in skeletal muscle even 1year after the exposure has ended.

      PubDate: 2017-02-24T04:47:03Z
      DOI: 10.1016/j.aquatox.2017.02.020
      Issue No: Vol. 186 (2017)
       
  • Molecular effectors in the chronic exposure to arsenic as early and
           sensitive biomarkers in developing Rhinella arenarum toads
    • Authors: Mariana Noelia Mardirosian; Danilo Guillermo Ceschin; Cecilia Inés Lascano; Andrés Venturino
      Pages: 19 - 27
      Abstract: Publication date: May 2017
      Source:Aquatic Toxicology, Volume 186
      Author(s): Mariana Noelia Mardirosian, Danilo Guillermo Ceschin, Cecilia Inés Lascano, Andrés Venturino
      Arsenic, a natural element of ecological relevance, is one of the most toxic elements present in various regions of the world. It can be found in natural water sources throughout Argentina in concentrations between 0.01 and 15mgL–1. The Argentinean autochthonous toad Rhinella arenarum was selected to study the molecular mechanisms involved in the effects and response to the chronic As exposure along its embryonic and larval development. We evaluated the effects on MAPK signal transduction pathway and transcription factors c-FOS and c-JUN, and the regulation of the expression at protein levels of different antioxidant enzymes. Our results indicated that As is modulating the MAPK pathway, increasing MEK and ERK levels both in the nuclear and post-nuclear fraction along the embryonic development and mainly at the beginning of the larval stage. Through this pathway, As can upregulate transcription factors like c-FOS and c-JUN, impacting the antioxidant response of the exposed embryos and larvae through antioxidant enzymes and recycling of GSH. Arsenic triggered specifically the synthesis of antioxidant enzymes in exposed R. arenarum embryo and larvae. In particular, the expression levels of SOD, CAT and GST enzymes analyzed by Western blot showed a similar behavior to their enzymatic activities in our previous work. This fact suggests that not only the synthesis of these antioxidant enzymes but also their rapid degradation after inactivation would be regulated in response to ROS levels. Antioxidant enzymes may show dual responses of induction and inactivation followed by degradation depending on the levels of oxidative stress and impact on ROS targets when the exposure is sustained in time and intensity. We also performed a probability of exceedence analysis including our previous results to visualize a progression of the response in time and also established the best early-responding biomarkers at the lowest As concentrations. As a conclusion, the molecular biomarkers such as the MAPKs MEK and ERK and transcription factors c-FOS and c-JUN are early induced in the response of developing toad embryos exposed to very low As concentrations in water. The advantage of counting with molecular biomarkers early responding to low concentrations of As in a chronic exposure is that they may anticipate the irreversible damage at later developmental stages due to the constant oxidative challenge.
      Graphical abstract image

      PubDate: 2017-04-22T08:07:40Z
      DOI: 10.1016/j.aquatox.2017.02.019
      Issue No: Vol. 186 (2017)
       
  • Effects of chronic exposure to dietary selenomethionine on the
           physiological stress response in juvenile white sturgeon (Acipenser
           transmontanus)
    • Authors: Sarah Patterson; Jenna Zee; Steve Wiseman; Markus Hecker
      Pages: 77 - 86
      Abstract: Publication date: May 2017
      Source:Aquatic Toxicology, Volume 186
      Author(s): Sarah Patterson, Jenna Zee, Steve Wiseman, Markus Hecker
      Selenium (Se) is an essential micronutrient, but at low concentrations can be toxic to aquatic organisms. Selenomethionine (SeMeth) is the primary dietary form of Se aquatic organisms are exposed to and is an environmental concern because it persists and bioaccumulates. White sturgeon (WS) might be particularly susceptible to bioaccumulative toxicants, such as SeMeth, due to their longevity and benthic lifestyle. Se exposure is known to have adverse effects on the physiological stress response in teleosts, but these effects are unknown in WS. Therefore, the goal of this study was to determine effects of dietary SeMeth on the ability of WS to mount a stress response. Juvenile WS were administered food spiked with 1.4, 5.6, 22.4 and 104.4μg Se/g dry mass (dm) for 72days. Lower doses were chosen to represent environmentally relevant concentrations, while the high dose represented a worst case scenario exposure. On day 72, fish were subjected to a 2min handling stressor, and they were sampled at 0, 2 and 24h post-stressor. Cortisol, glucose and lactate concentrations were quantified in blood plasma and glycogen concentrations were quantified in muscle and liver. Transcript abundance of genes involved in corticosteroidogenesis and energy metabolism were determined using qPCR. Under basal conditions, WS fed 104.4μg Se/g dm had significantly greater concentrations of plasma cortisol and lactate, and significantly lower concentrations of plasma glucose and liver glycogen, compared to controls. Corticosteroid 11-beta dehydrogenase 2 (hsd11b2) abundance was lower in WS fed 22.4 and 104.4μg Se/g dm, indicating less conversion of cortisol to cortisone. Abundance of the glucocorticoid receptor (gcr) was significantly lower in high dose WS, suggesting lower tissue sensitivity to glucocorticoids. The increasing trend in phosphoenolpyruvate carboxykinase (pepck) abundance, with increasing SeMeth exposure, was consistent with greater cortisol and glucose concentrations in high dose WS. Exposure to an acute handling stressor elicited a typical cortisol response, but the magnitude of the response appeared to be significantly lower than those typically observed in teleosts. SeMeth also did not appear to modulate the cortisol response to a secondary stressor. However, WS exposed to 22.4μg Se/g dm and sampled 2h post-stressor, had significantly higher concentrations of muscle glycogen compared to controls, indicating effects on their ability to utilize muscle glycogen for energy. Overall, the results indicate that chronic exposure to dietary SeMeth concentrations >22.4μg/g can affect cortisol dynamics and mobilization of energy substrates in juvenile WS.

      PubDate: 2017-03-09T05:06:20Z
      DOI: 10.1016/j.aquatox.2017.02.003
      Issue No: Vol. 186 (2017)
       
  • Microcystin-LR induces changes in the GABA neurotransmitter system of
           zebrafish
    • Authors: Wei Yan; Li Li; Guangyu Li; Sujuan Zhao
      Abstract: Publication date: Available online 15 May 2017
      Source:Aquatic Toxicology
      Author(s): Wei Yan, Li Li, Guangyu Li, Sujuan Zhao
      It has been reported that exposure to microcystins altered adult zebrafish swimming performance parameters, but the possible mechanisms of action remain unknown. Neuronal activity depends on the balance between the number of excitatory and inhibitory processes which are associated with neurotransmitters. In the present study, zebrafish embryos (5 d post-fertilization) were exposed to 0, 0.3, 3 and 30μg/L (microcystin-LR) MCLR for 90day until reaching sexual maturity. To investigate the effects of MCLR on the neurotransmitter system, mRNA levels involved in amino acid g-aminobutyric acid (GABA) and glutamate metabolic pathways were tested using quantitative real-time PCR. Significant increase of GABAA receptor, alpha 1 (gabra1), glutamate decarboxylase (gad1b), glutaminase (glsa) and reduction of mRNA expression of GABA transporter (gat1) at transcriptional level were observed in the brain. Meanwhile, western blotting showed that the protein levels of gabra1, gad1b were induced by MCLR, whereas the expression of gat1 was decreased. In addition, MCLR induced severe damage to cerebrum ultrastructure, showing edematous and collapsed myelinated nerve fibers, distention of endoplasmic reticulum and swelling mitochondria. Our results suggested that MCLR showed neurotoxicity in zebrafish which might attribute to the disorder of GABA neurotransmitter pathway.

      PubDate: 2017-05-19T21:21:24Z
      DOI: 10.1016/j.aquatox.2017.05.006
       
  • Metabolic Profiling of Goldfish (Carassius auratis) After Long-term
           Glyphosate-based Herbicide Exposure
    • Authors: Ming-Hui Li; Ling-Yu Ruan; Jin-Wei Zhou; Yong-Hong Fu; Lei Jiang; He Zhao; Jun-Song Wang
      Abstract: Publication date: Available online 13 May 2017
      Source:Aquatic Toxicology
      Author(s): Ming-Hui Li, Ling-Yu Ruan, Jin-Wei Zhou, Yong-Hong Fu, Lei Jiang, He Zhao, Jun-Song Wang
      Glyphosate is an efficient herbicide widely used worldwide. However, its toxicity to non-targeted organisms has not been fully elucidated. In this study, the toxicity of glyphosate-based herbicide was evaluated on goldfish (Carassius auratus) after long-term exposure. Tissues of brains, kidneys and livers were collected and submitted to NMR-based metabolomics analysis and histopathological inspection. Plasma was collected and the blood biochemical indexes of AST, ALT, BUN, CRE, LDH, SOD, GSH-Px, GR and MDA were measured. Long-term glyphosate exposure caused disorders of blood biochemical indexes and renal tissue injury in goldfish. Metabolomics analysis combined with correlation network analysis uncovered significant perturbations in oxidative stress, energy metabolism, amino acids metabolism and nucleosides metabolism in glyphosate dosed fish, which provide new clues to the toxicity of glyphosate. This integrated metabolomics approach showed its applicability in discovering the toxic mechanisms of pesticides, which provided new strategy for the assessment of the environmental risk of herbicides to non-target organisms.

      PubDate: 2017-05-14T21:19:45Z
      DOI: 10.1016/j.aquatox.2017.05.004
       
  • Developing transcriptional profiles in Orbicella franksi exposed to
           copper: Characterizing responses associated with a spectrum of
           laboratory-controlled environmental conditions
    • Authors: Michael B. Morgan; Sara E. Edge; Alexander A. Venn; Ross J. Jones
      Abstract: Publication date: Available online 12 May 2017
      Source:Aquatic Toxicology
      Author(s): Michael B. Morgan, Sara E. Edge, Alexander A. Venn, Ross J. Jones


      PubDate: 2017-05-14T21:19:45Z
      DOI: 10.1016/j.aquatox.2017.05.005
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: June 2017
      Source:Aquatic Toxicology, Volume 187


      PubDate: 2017-05-10T07:18:26Z
       
  • Microcystin-LR bioconcentration induces antioxidant responses in the
           digestive gland of two marine bivalves Crassostrea gigas and Mytilus
           edulis
    • Authors: Young Dae Kim; Won Jin Kim; Yun Kyung Shin; Do-Hee Lee; Youn-Jung Kim; Jang Kyun Kim; Jae-Sung Rhee
      Abstract: Publication date: Available online 8 May 2017
      Source:Aquatic Toxicology
      Author(s): Young Dae Kim, Won Jin Kim, Yun Kyung Shin, Do-Hee Lee, Youn-Jung Kim, Jang Kyun Kim, Jae-Sung Rhee
      Microcystins (MCs) are a major group of potent cyanobacterial toxins found in freshwater and even brackish waterbodies. To understand the putative correlation between bioconcentration of MCs and antioxidant responses of the digestive gland of bivalves, Pacific oyster Crassostrea gigas and blue mussel Mytilus edulis were exposed to different concentrations (0.1, 1, 10 and 20μgL−1) of MC-Leucine-Arginine (LR) for seven days. MC-LR bioconcentrated in the digestive glands of both bivalves during exposure period. The levels were slightly reduced when the bivalves were exposed to seawater during depuration (7 days), while approximately 0.1μgL−1 of MC-LR was observed in the 10 and 20μgL−1 exposed bivalves at the end of depuration. Intracellular malondialdehyde (MDA) and glutathione (GSH) levels were significantly elevated in the 10 and 20μgL−1 exposed bivalves at 7day, and the levels were maintained during depuration in both bivalves. Overall, significant higher levels of enzymatic activities of antioxidant defense systems such as glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed in the 10 and 20μgL−1 exposed bivalves. Interestingly, most of higher levels of Pacific oyster were detected at exposure period, while blue mussel showed higher levels at depuration phase, suggesting a species-specific sensitivity upon MC-LR. These patterns were correlated with the bioconcentration patterns of MC-LR as Pacific oyster was highly accumulated by MC-LR during exposure period, but blue mussel showed prolonged high levels of MC-LR for depuration phase. Our results will be useful to understand species-specific bioconcentration of MC-LR in bivalves and their effects on intracellular oxidative status via accumulation.

      PubDate: 2017-05-10T07:18:26Z
      DOI: 10.1016/j.aquatox.2017.05.003
       
  • TRIBUTYLTIN AND TRIPHENYLTIN EXPOSURE PROMOTES IN VITRO ADIPOGENIC
           DIFFERENTIATION BUT ALTERS THE ADIPOCYTE PHENOTYPE IN RAINBOW TROUT
    • Authors: Esmail Lutfi; Natàlia Riera-Heredia; Marlon Córdoba; Cinta Porte; Joaquim Gutiérrez; Encarnación Capilla; Isabel Navarro
      Abstract: Publication date: Available online 8 May 2017
      Source:Aquatic Toxicology
      Author(s): Esmail Lutfi, Natàlia Riera-Heredia, Marlon Córdoba, Cinta Porte, Joaquim Gutiérrez, Encarnación Capilla, Isabel Navarro
      Numerous environmental pollutants have been identified as potential obesogenic compounds affecting endocrine signaling and lipid homeostasis. Among them, organotins such as tributyltin (TBT) and triphenyltin (TPT), can be found in significant concentrations in aquatic environments. The aim of the present study was to investigate in vitro the effects of TBT and TPT on the development and lipid metabolism of rainbow trout (Onchorynchus mykiss) primary cultured adipocytes. Results showed that TBT and TPT induced lipid accumulation and slightly enhanced peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα) protein expression when compared to a control, both in the presence or absence of lipid mixture. Notwithstanding, the effects were higher when combined with lipid, and in the absence of it, the organotins did not cause complete mature adipocyte morphology. Regarding gene expression analyses, exposure to TBT and TPT caused an increase in fatty acid synthase (fasn) mRNA levels confirming the pro-adipogenic properties of these compounds. In addition, when added together with lipid, TBT and TPT significantly increased cebpa, tumor necrosis factor alpha (tnfa) and ATP-binding cassette transporter 1 (abca1) mRNA levels suggesting a synergistic effect. Overall, our data highlighted that TBT and TPT activate adipocyte differentiation in rainbow trout supporting an obesogenic role for these compounds, although by themselves they are not able to induce complete adipocyte development and maturation suggesting that these adipocytes might not be properly functional.

      PubDate: 2017-05-10T07:18:26Z
      DOI: 10.1016/j.aquatox.2017.05.001
       
  • The Effects of Copper Oxide Nanoparticles on Dorsoventral Patterning,
           Convergent Extension, and Neural and Cardiac Development of Zebrafish
    • Authors: Jia Xu; Qiuping Zhang; Xu Li; Sihui Zhan; Lifeng Wang; Dongyan Chen
      Abstract: Publication date: Available online 4 May 2017
      Source:Aquatic Toxicology
      Author(s): Jia Xu, Qiuping Zhang, Xu Li, Sihui Zhan, Lifeng Wang, Dongyan Chen
      Currently, nanoparticles are widely used in biomedicine and industry. CuO nanoparticles (CuO-NPs) are versatile materials in our daily life and their toxicity has drawn extensive attention. In this study, we concentrate on the effect of CuO-NPs on early zebrafish development. The results reveal that CuO-NPs can induce abnormal phenotypes of a smaller head and eyes and delayed epiboly. The gene expression pattern shows that CuO-NPs spatially narrow the expression of dorsal genes chordin and goosecoid and alter the expression of dlx3, ntl and hgg which are related to the cell migration of gastrulation. The decreased expression of pax2 and pax6 involved in neural differentiation was accordant with the decreased sizes of neural structures. Cmlc2 expression suggests that CuO-NPs prevented looping of the heart tube during cardiogenesis. Furthermore, quantitative RT-PCR results suggest that the CuO-NPs could increase the canonical Wnt signaling pathway to narrow the expression of chordin and goosecoid in dorsoventral patterning as well as decrease the transcription of Wnt5 and Wnt11 to result in slower, less directed movements and an abnormal cell shape. These findings indicated the CuO-NPs exert developmental toxicity. The present study evaluates the ecological and developmental toxicity, providing warnings about the application of CuO-NPs.

      PubDate: 2017-05-05T07:13:28Z
      DOI: 10.1016/j.aquatox.2017.05.002
       
  • Effects of diclofenac on the expression of Nrf2 and its downstream target
           genes in mosquito fish (Gambusia affinis)
    • Authors: Shuang Bao; Xiangping Nie; Ruikang Ou; Chao Wang; Peijia Ku; Kaibing Li
      Abstract: Publication date: Available online 20 April 2017
      Source:Aquatic Toxicology
      Author(s): Shuang Bao, Xiangping Nie, Ruikang Ou, Chao Wang, Peijia Ku, Kaibing Li
      Diclofenac (DCF) is one of widely used non-steroidal anti-inflammatory drugs. Recently, this drug has been universally detected in aquatic environment. However, its potential adverse effects and oxidative stress toxic mechanisms on fish remain unclear. In the present study, we first cloned the crucial partial sequences of some key oxidative stress related genes, which include NF-E2-related factor 2 (Nrf2), NAD(P)H: quinoneoxidoreductase (NQO1), glutamate-cysteine ligase catalytic subunit (GCLC), Cu-Zn superoxide dismutase (SOD2), catalase (CAT), alpha-glutathione S-transferase (GSTA), and UDP-glucuronosyltransferases (UGT) in mosquito fish (Gambusia affinis). We also deduced amino acids of Nrf2 and then constructed the phylogenetic trees of Nrf2, NQO1 and GCLC, respectively. Results showed that a high identity percentage was founded between G. affinis and other bony fish species, such as Xiphophorus maculates and Poecilia reticulate. The transcriptional expression of these genes and partly related enzymes activities were then investigated under the included environmental relevant concentration DCF exposure (0μmolL−1, 1.572×10-3 μmolL−1, 1.572×10-2 μmolL−1, 0.1572μmolL−1 and 1.572μmolL−1) for 24h and 168h. The expression of Nrf2 was inhibited at 24h but induced at 168h, exhibiting a significant time and/or dose-effect relationship under DCF exposure. Similar observation was found in its downstream target genes. However, Nrf2-mediated antioxidant enzymes activities displayed differently under the same concentration of DCF exposure for the same time. Under DCF exposure for 168h, the genes exhibited dramatic induction trend, but there were no significant changes in enzyme activities and MDA content. Overall, mRNA responses were more sensitive than enzyme changes in mosquito fish under DCF exposure.

      PubDate: 2017-04-22T08:07:40Z
      DOI: 10.1016/j.aquatox.2017.04.008
       
  • Toxicity of clomazone and its formulations to zebrafish embryos (Danio
           rerio)
    • Authors: Marija Stevanovic; Slavica Gasic; Marek Pipal; Lucie Blahova; Dragica Brkic; Nesko Neskovic; Klara Hilscherova
      Abstract: Publication date: Available online 19 April 2017
      Source:Aquatic Toxicology
      Author(s): Marija Stevanovic, Slavica Gasic, Marek Pipal, Lucie Blahova, Dragica Brkic, Nesko Neskovic, Klara Hilscherova
      Herbicides are the most widely used group of pesticides but after reaching water bodies they are able to cause adverse effects on non-target organisms. Different formulations using the same active ingredient are frequently available, which raises the issue of potential influence of different formulation types on herbicide toxicity. The present study evaluated the toxicity and teratogenic effects of the active ingredient clomazone and its two formulations (Rampa® EC and GAT Cenit 36 CS, both containing 360g a.i./l of clomazone) on zebrafish embryos. The crucial difference between the two formulation types is the way of active substance release. This investigation is the first report on zebrafish embryotoxicity of both clomazone and its formulations. The technical active ingredient and formulations caused mortality and diverse teratogenic effects, showing different levels of toxicity. The LC50 values for the technical ingredient, Rampa® EC and GAT Cenit 36 CS were 61.4, 9.6 and 92.5mg a.i./l, respectively. Spontaneous movements in 22 hpf embryos decreased under exposure to both the technical ingredient and formulations. A significant number of underdeveloped embryos was detected after exposure to clomazone and Rampa® EC, while no underdevelopment was noted in embryos exposed to GAT Cenit 36 CS. Exposure to the technical ingredient and formulations led also to a series of morphological changes and interfered with the growth of zebrafish embryos. The EC50 based on detection of edemas, spine and tail tip deformations and gas bladder absence (120hpf) was 12.1, 10.1 and 24.1mg/l for technical clomazone, Rampa® EC and GAT Cenit 36 CS, while teratogenicity index (TI) based on LC50/EC50 ratio was 5.1, 1 and 3.8, respectively. The data in this study showed that the emulsifiable concentrate formulation (Rampa® EC) caused statistically significantly higher toxicity, and the aqueous capsule suspension (GAT Cenit 36 CS) lower toxicity than technical clomazone. It indicates that different formulations with the same active ingredient may have different environmental impacts, which is why risk assessment based only on active ingredient toxicity might not be sufficient in terms of preventing formulation effects on the environment.

      PubDate: 2017-04-22T08:07:40Z
      DOI: 10.1016/j.aquatox.2017.04.007
       
  • Toxicity and Bioaccumulation of Three Hexabromocyclododecane
           Diastereoisomers in the Marine Copepod Tigriopus japonicas
    • Authors: Haizheng Hong; Dongmei Lv; Wanxin Liu; Lingming Huang; Leyun Chen; Rong Shen; Dalin Shi
      Abstract: Publication date: Available online 18 April 2017
      Source:Aquatic Toxicology
      Author(s): Haizheng Hong, Dongmei Lv, Wanxin Liu, Lingming Huang, Leyun Chen, Rong Shen, Dalin Shi
      The three major hexabromocyclododecane (HBCD) diastereoisomers, i.e. α-, β- and γ-HBCD, have distinct physical and chemical properties that may potentially result in different levels of bioaccumulation and toxicity in aquatic organisms. To assess the impact of diastereomeric variation in HBCDs, the marine copepod Tigriopus japonicus was exposed to α-, β- and γ-HBCD in isolation. Results showed that all the three diastereoisomers had a similar potency to cause growth delay in T. japonicas. Variation was observed in the overall survival rate with exposure to α- and β-HBCD, and this resulted in significantly higher lethal toxicity in T. japonicas than that with exposure to γ-HBCD. Exposure to α-, β- and γ-HBCD led to the generation of ROS in T. japonicas, a possibly toxic mechanism. Both α- and β-HBCD showed a higher potential to induce oxidative stress, which may be a factor in the higher lethal toxicity observed with α- and β-HBCD exposure. It is of note that T. japonicus was found to be more sensitive to all three diastereoisomers in the F1 generation than in the F0 generation. The bioconcentration potential of HBCD diastereoisomers can be ranked in the order α-HBCD >γ-HBCD >β-HBCD and was found to be higher in T. japonicus than has been reported for fish species.

      PubDate: 2017-04-22T08:07:40Z
      DOI: 10.1016/j.aquatox.2017.04.010
       
  • Dechlorane Plus induces oxidative stress and decreases cyclooxygenase
           activity in the blue mussel
    • Authors: Pierre-Luc Gagné; Marlène Fortier; Marc Fraser; Lise Parent; Cathy Vaillancourt; Jonathan Verreault
      Abstract: Publication date: Available online 17 April 2017
      Source:Aquatic Toxicology
      Author(s): Pierre-Luc Gagné, Marlène Fortier, Marc Fraser, Lise Parent, Cathy Vaillancourt, Jonathan Verreault
      Dechlorane Plus (DP) is a chlorinated flame retardant used mainly in electrical wire and cable coating, computer connectors, and plastic roofing materials. Concentrations of DP (syn and anti isomers) are increasingly being reported in aquatic ecosystems worldwide. However, there is exceedingly little information on the exposure-related toxicity of DP in aquatic organisms, especially in bivalves. The objective of this study was to investigate the in vivo and in vitro effects of DP exposure on histopathology, lipid peroxidation (LPO) levels, cyclooxygenase (COX) activity, phagocytosis capacity and efficiency, and DNA strand breakage in the blue mussel (Mytilus edulis) following a 29days exposure (0.001, 0.01, 0.1 and 1.0μg DP/L). Blue mussels accumulated DP in muscle and digestive gland in a dose-dependent manner. LPO levels in gills were found to increase by 82% and 67% at the 0.01 and 1.0μg DP/L doses, respectively, while COX activity in gills decreased by 44% at the 1μg/L dose. No histopathological lesion was found in gonads following DP exposure. Moreover, no change in hemocyte DNA strand breakage, phagocytosis rate, and viability was observed following DP exposure. Present study showed that toxicity of DP may occur primarily via oxidative stress in the blue mussel and potentially other bivalves, and that gills represent the most responsive tissue to this exposure.

      PubDate: 2017-04-22T08:07:40Z
      DOI: 10.1016/j.aquatox.2017.04.009
       
  • Toxicity assessment of ZnO-decorated Au nanoparticles in the Mediterranean
           clam Ruditapes decussatus
    • Authors: Badreddine Sellami; Amine Mezni Abdelhafidh Khazri Imen Bouzidi Wiem Saidani
      Abstract: Publication date: Available online 15 April 2017
      Source:Aquatic Toxicology
      Author(s): Badreddine Sellami, Amine Mezni, Abdelhafidh Khazri, Imen Bouzidi, Wiem Saidani, David Sheehan, Hamouda Beyrem
      The synthesis of hybrid nanomaterials has greatly increased in recent years due to their special physical and chemical properties. However, information regarding the environmental toxicity associated with these chemicals is limited, in particular in the aquatic environment. In the present study, an experiment was performed in which the marine bivalve (Ruditapes decussatus) was exposed for 14days to 2 concentrations of zinc oxide-decorated Au nanoparticles (Au-ZnONPs: Au-ZnONP50=50μg/l; Au-ZnONP100=100μg/l). The stability and resistance of Au-ZnONPs in the natural seawater were assessed by combining transmission electron microscopy and dynamic light scattering. Inductively coupled plasma-atomic emission spectroscopy revealed uptake of these nanoparticles within clams and their ability to induce metallic deregulation. The results obtained indicate that Au-ZnONPs induce biochemical and histological alterations within either the digestive gland or gill tissues at high concentration. This was deduced from the significant increase in H2O2 level, superoxide dismutase and catalase activities and malondialdehyde content. Furthermore, the toxicity of Au-ZnO nanoparticles was linked with the increase of intracellular iron and calcium levels in both tissues. Histological alterations in gill and digestive gland were more pronounced with Au-ZnONP100 and this is likely related to oxidative mechanisms. Gill and digestive gland are differentially sensitive to Au-ZnONPs if the exposure concentration is higher than 50μg/L. In conclusion, the parameters considered here could constitute reliable biomarkers for evaluation of hybrid nanoparticles toxicity in environmental model organisms. In addition, based on the results obtained, gill and digestive gland of R. decussatus could be proposed as models to detect harmful effects of hybrid nanoparticles.

      PubDate: 2017-04-15T08:03:32Z
       
  • Characterisation of Pb-induced changes and prediction of Pb exposure in
           microalgae using infrared spectroscopy
    • Authors: Dao John; Beardall Philip Heraud
      Abstract: Publication date: Available online 14 April 2017
      Source:Aquatic Toxicology
      Author(s): Ly Dao, John Beardall, Philip Heraud
      Macromolecular changes in Chlorella sp. FleB1 and Scenedesmus acutus YaA6 exposed to Pb were characterised by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Spectra were collected in the mid-infrared spectral region and a chemometric approach was used to analyse the spectra. Principal Component Analysis showed that under Pb treatment, carbohydrates and lipids increased while proteins and phosphorylated molecules decreased in both the isolates. These conclusions were corroborated by conventional measurements of photosynthesis and neutral lipids. In the two strains, Pb inhibited photosynthesis, which directly affects the synthesis of polysaccharides and other macromolecules. Neutral lipids as measured by Nile Red were increased in lead-treated samples. Modelling of spectral data against Pb exposure levels allowed Pb-exposed samples to be readily discriminated from unexposed controls and the level of Pb exposure could be predicted with good accuracy in independent validation testing. This study demonstrates the utility of the spectroscopic approach as a rapid, inexpensive, non-destructive method to understand changes in cellular composition induced by Pb and allowing detection and quantification of Pb levels in metal-contaminated cells in a “snapshot”.

      PubDate: 2017-04-15T08:03:32Z
       
  • Histological alterations in gills of Macrobrachium amazonicum juveniles
           exposed to ammonia and nitrite
    • Authors: Fabrício Martins Dutra; Milton Rönnau; Dircelei Sponchiado; Sandra Carla Forneck; Carolina Arruda Freire; Eduardo Luis Cupertino Ballester
      Abstract: Publication date: Available online 8 April 2017
      Source:Aquatic Toxicology
      Author(s): Fabrício Martins Dutra, Milton Rönnau, Dircelei Sponchiado, Sandra Carla Forneck, Carolina Arruda Freire, Eduardo Luis Cupertino Ballester
      Aquaculture has shown great growth in the last decades. Due to the restrictions on water use, production systems are becoming increasingly more intensive, raising concerns about the production water quality. Macrobrachium amazonicum is among the freshwater prawn species with favorable characteristics for production and possibility of intensification. Nitrogen compounds such as ammonia and nitrite affect the health of aquatic organisms since they quickly reach toxic concentrations. These compounds can also cause damage to the gill structure, leading to hypoxia in tissues, affecting acid-base balance, osmoregulation (salt absorption) and ammonia excretion, decreasing the immune capacity of the animal and, in extreme cases, cause death. The aim of this study was to assess histological changes in the gills of Macrobrachium amazonicum juveniles subjected to different concentrations of total ammonia and nitrite. The prawns were subjected to different concentrations of those compounds and their gills were removed and preserved for histological analysis. The gills were assessed for changes according to the Organ Index (Iorg ) and, for each change, an importance factor (w) was attributed according to the degree of reversibility and applied according to the degree of extension or frequency of the damage. The damage to the gills in the treatments with 100% mortality, both for ammonia and nitrite, corresponded to the high occurrence of progressive, regressive, circulatory, and inflammation damages. The other treatments (which caused less mortality) had mainly inflammation and regressive damages, whose occurrence increased according to the increase in ammonia and nitrite concentration. The histological analysis confirmed that the higher the total ammonia and nitrite concentrations, the larger the damages caused to the gill structure and that lower nitrite concentrations caused similar damages to those caused by higher total ammonia concentrations, which reflects the lower capacity M. amazonicum has to tolerate nitrite.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.04.003
       
  • Cross-interference of two model peroxisome proliferators in peroxisomal
           and estrogenic pathways in brown trout hepatocytes
    • Authors: Tânia Vieira Madureira; Ivone Pinheiro; Fernanda Malhão; Célia Lopes; Ralph Urbatzka; L. Filipe C. Castro; Eduardo Rocha
      Abstract: Publication date: Available online 6 April 2017
      Source:Aquatic Toxicology
      Author(s): Tânia Vieira Madureira, Ivone Pinheiro, Fernanda Malhão, Célia Lopes, Ralph Urbatzka, L. Filipe C. Castro, Eduardo Rocha
      Peroxisome proliferators cause species-specific effects, which seem to be primarily transduced by peroxisome proliferator-activated receptor alpha (PPARα). Interestingly, PPARα has a close interrelationship with estrogenic signaling, and this latter has already been promptly activated in brown trout primary hepatocytes. Thus, and further exploring this model, we assess here the reactivity of two PPARα agonists in direct peroxisomal routes and, in parallel the cross-interferences in estrogen receptor (ER) mediated paths. To achieve these goals, three independent in vitro studies were performed using single exposures to clofibrate − CLF (50, 500 and 1000μM), Wy-14643–Wy (50 and 150μM), GW6471–GW (1 and 10μM), and mixtures, including PPARα agonist or antagonist plus an ER agonist or antagonist. Endpoints included gene expression analysis of peroxisome/lipidic related genes (encoding apolipoprotein AI − ApoAI, fatty acid binding protein 1–Fabp1, catalase − Cat, 17 beta-hydroxysteroid dehydrogenase 4–17β-HSD4, peroxin 11 alpha − Pex11α, PPARαBb, PPARαBa and urate oxidase − Uox) and those encoding estrogenic targets (ERα, ERβ-1 and vitellogenin A − VtgA). A quantitative morphological approach by using a pre-validated catalase immunofluorescence technique allowed checking possible changes in peroxisomes. Our results show a low responsiveness of trout hepatocytes to model PPARα agonists in direct target receptor pathways. Additionally, we unveiled interferences in estrogenic signaling caused by Wy, leading to an up-regulation of genes encoding VtgA and ERα at 150μM; these effects seem counteracted with a co-exposure to an ER antagonist. The present data stress the potential of this in vitro model for further exploring the physiological/toxicological implications related with this nuclear receptor cross-regulation.

      PubDate: 2017-04-08T12:07:03Z
      DOI: 10.1016/j.aquatox.2017.04.001
       
  • Primary hepatocytes from Arctic char (Salvelinus alpinus) as a relevant
           Arctic in vitro model for screening contaminants and environmental
           extracts
    • Authors: Karina Petersen; Maria T. Hultman; Knut Erik Tollefsen
      Abstract: Publication date: Available online 2 April 2017
      Source:Aquatic Toxicology
      Author(s): Karina Petersen, Maria T. Hultman, Knut Erik Tollefsen
      Contaminants find their way to the Arctic through long-range atmospheric transport, transport via ocean currents, and through increased anthropogenic activity. Some of the typical pollutants reaching the Arctic (PAHs, PCBs) are known to induce cytochrome P450 1a (CYP1A) protein expression and ethoxyresorufin-O-deethylase (EROD) activity through the aryl hydrocarbon receptor (AhR). In addition, some endocrine disrupting chemicals (EDCs) such as estrogen mimics (xenoestrogens) have been documented in Arctic areas and they may interfere with natural sexual development and reproduction. In vitro assays that are capable of detecting effects of such pollutants, covering multiple endpoints, are generally based on mammalian or temperate species and there are currently no well-characterized cell-based in vitro assays for effect assessment from Arctic fish species. The present study aimed to develop a high-throughput and multi-endpoint in vitro assay from Arctic char (Salvelinus alpinus) to provide a non-animal (alternative) testing method for an ecologically relevant Arctic species. A method for isolation and exposure of primary hepatocytes from Arctic char for studying the toxic effects and mode of action (MoA) of pollutants was applied and validated. The multi-versatility of the bioassay was assessed by classical biomarker responses such as cell viability (membrane integrity and metabolic activity), phase I detoxification (CYP1A protein expression, EROD activity) and estrogen receptor (ER) mediated vitellogenin (Vtg) protein expression using a selection of model compounds, environmental pollutants and an environmental extract containing a complex mixture of pollutants. Primary hepatocytes from Arctic char were successfully isolated and culture conditions optimized to identify the most optimal assay conditions for covering multiple endpoints. The hepatocytes responded with concentration-dependent responses to all of the model compounds, most of the environmental pollutants and the environmental sample tested. The bioassay response and sensitivity of the hepatocytes from Arctic char differed slightly from closely related salmonid species, thus highlighting the need for developing in vitro assays relevant for Arctic species. The present multi-endpoint in vitro assay offer a highly versatile tool to screen potential effects of pollutants and complex samples relevant for Arctic exposure scenarios.

      PubDate: 2017-04-02T11:58:17Z
      DOI: 10.1016/j.aquatox.2017.03.023
       
  • Membrane lipid profiles of coral responded to zinc oxide
           nanoparticle-induced perturbations on the cellular membrane
    • Authors: Chuan-Ho Tang; Ching-Yu Lin; Shu-Hui Lee; Wei-Hsien Wang
      Abstract: Publication date: Available online 31 March 2017
      Source:Aquatic Toxicology
      Author(s): Chuan-Ho Tang, Ching-Yu Lin, Shu-Hui Lee, Wei-Hsien Wang
      Zinc oxide nanoparticles (nZnOs) released from popular sunscreens used during marine recreation apparently endanger corals; however, the known biological effects are very limited. Membrane lipids constitute the basic structural element to create cell a dynamic structure according to the circumstance. Nano-specific effects have been shown to mechanically perturb the physical state of the lipid membrane, and the cells accommodating the actions of nZnOs can be involved in the alteration of the membrane lipid composition. To gain insight into the effects of nanoparticles on coral, glycerophosphocholine (GPC) profiling of the coral Seriatopora caliendrum exposed to nZnOs was performed in this study. Increasing lyso-GPCs, docosapentaenoic acid-possessing GPCs and docosahexaenoic acid-possessing GPCs and decreasing arachidonic acid-possessing GPCs were the predominant changes responded to nZnO exposure in the coral. A backfilling of polyunsaturated plasmanylcholines was observed in the coral exposed to nZnO levels over a threshold. These changes can be logically interpreted as an accommodation to nZnOs-induced mechanical disturbances in the cellular membrane based on the biophysical properties of the lipids. Moreover, the coral demonstrated a difference in the changes in lipid profiles between intra-colonial functionally differentiated polyps, indicating an initial membrane composition-dependent response. Based on the physicochemical properties and physiological functions of these changed lipids, some chronic biological effects can be incubated once the coral receives long-term exposure to nZnOs.

      PubDate: 2017-04-02T11:58:17Z
      DOI: 10.1016/j.aquatox.2017.03.021
       
  • Extreme nitrite tolerance in the clown knifefish Chitala ornata is linked
           to up-regulation of methaemoglobin reductase activity
    • Authors: Le Thi Hong Gam; Frank Bo Jensen; Christian Damsgaard; Do Thi Thanh Huong; Nguyen Thanh Phuong; Mark Bayley
      Abstract: Publication date: Available online 19 March 2017
      Source:Aquatic Toxicology
      Author(s): Le Thi Hong Gam, Frank Bo Jensen, Christian Damsgaard, Do Thi Thanh Huong, Nguyen Thanh Phuong, Mark Bayley
      The clown knifefish is a facultative air breather, which is widely farmed in freshwater ponds in Vietnam. Here we report a very high nitrite tolerance (96h LC50 of 7.82mM) in this species and examine the effects of 1mM (LC5) and 2.5mM (LC10) ambient nitrite on haemoglobin (Hb) derivatives, electrolyte levels, acid-base status, and total body water content during 7days of exposure. Furthermore, we tested the hypothesis that erythrocyte methaemoglobin (metHb) reductase activity is upregulated by nitrite exposure. Plasma nitrite levels increased for 2–3days but stayed below environmental levels and fell towards control values during the last half of the exposure period. Plasma nitrate, in contrast, rose continuously, reflecting detoxification of nitrite to nitrate. MetHb generated from the reaction between nitrite and erythrocyte Hb reached 38% at day 2, but then decreased to 17% by the end of experiment. The first order rate constant for metHb reduction by erythrocyte metHb reductase increased from 0.01 in controls to 0.046min−1 after 6days of nitrite exposure, showing up-regulation of this enzyme. While such upregulation has been suggested in nitrite-exposed fish species, this study provides the first experimental evidence.

      PubDate: 2017-03-20T05:19:36Z
      DOI: 10.1016/j.aquatox.2017.03.013
       
  • Interaction between the zebrafish (Danio rerio) organic cation transporter
           1 (Oct1) and endo- and xenobiotics
    • Authors: Mihaljević Ivan; Popović Marta; Žaja Roko; Maraković Nikola; Šinko Goran; Smital Tvrtko
      Abstract: Publication date: Available online 18 March 2017
      Source:Aquatic Toxicology
      Author(s): Mihaljević Ivan, Popović Marta, Žaja Roko, Maraković Nikola, Šinko Goran, Smital Tvrtko
      Organic cation transporters (OCTs) serve as uptake transporters of numerous endo- and xenobiotics. They have been in the focus of medical toxicological research for more than a decade due to their key role in absorption, distribution, metabolism and excretion due to their expression on basolateral membranes of various barrier tissues. OCTs belong to the SLC22A family within the SLC (Solute carrier) protein superfamily, with three co-orthologs identified in humans (OCT1, 2 and 3), and two Oct orthologs in zebrafish (Oct1 and Oct2). The structural and functional properties of zebrafish Octs, along with their toxicological relevance, have still not been explored. In this study, we performed a functional characterization of zebrafish Oct1 using transient and stable heterologous expression systems and model fluorescent substrates as the basis for interaction studies with a wide range of endo- and xenobiotics. We also conducted a basic topology analysis and homology modeling to determine the structure and membrane localization of Oct1. Finally, we performed an MTT assay to evaluate the toxic effects of the seven interactors identified – oxaliplatin, cisplatin, berberine, MPP+, prazosin, paraquat and mitoxantrone – in human embryonic kidney cells (HEK293T) stably expressing zebrafish Oct1 (HEK293T-drOct1 cells). Our results show that the zebrafish Oct1 structure consists of 12 transmembrane alpha helices, which form the active region with more than one active site. Five new fluorescent substrates of Oct1 were identified: ASP+ (Km =26μM), rhodamine 123 (Km =103.7nM), berberine (Km =3.96μM), DAPI (Km =780nM), and ethidium bromide (Km =97nM). Interaction studies revealed numerous interactors that inhibited the Oct1-dependent uptake of fluorescent substrates. The identified interactors ranged from physiological compounds (mainly steroid hormones) to different classes of xenobiotics, with IC50 values in nanomolar (e.g., pyrimethamine and prazosin) to millimolar range (e.g., cimetidine). Cytotoxicity experiments with HEK293T-drOct1 cells enabled us to identify berberine, oxaliplatin and MPP+ as substrates of Oct1. The data presented in this study provide the first insights into the functional properties of zebrafish Oct1 and offer an important basis for more detailed molecular and ecotoxicological characterizations of this transporter.

      PubDate: 2017-03-20T05:19:36Z
      DOI: 10.1016/j.aquatox.2017.03.012
       
  • The impacts of emergent pollutants on Ruditapes philippinarum: biochemical
           responses to carbon nanoparticles exposure
    • Authors: Lucia De Marchi; Victor Neto; Carlo Pretti; Etelvina Figueira; Federica Chiellini; Amadeu M.V.M. Soares; Rosa Freitas
      Abstract: Publication date: Available online 18 March 2017
      Source:Aquatic Toxicology
      Author(s): Lucia De Marchi, Victor Neto, Carlo Pretti, Etelvina Figueira, Federica Chiellini, Amadeu M.V.M. Soares, Rosa Freitas
      Multi-walled carbon nanotubes (MWCNTs) are one of the most important carbon Nanoparticles (NPs). The production and use of these NPs is increasing rapidly and, therefore, the need to assess their presence in the environment and associated risks has become of prime importance. Recent studies demonstrated the impacts of different NPs on bivalves, a taxonomic group where species tolerance to anthropogenic stressors, such as pollutants, is widely variable. The Manila clam Ruditapes philippinarum is one of the most commonly used bivalve species in environmental monitoring studies and ecotoxicology tests, however, to our knowledge, no information is available on biochemical alterations on this species due to MWCNTs exposure. Thus, the present study aimed to assess the toxic effects of different MWCNT concentrations (0.01; 0.10 and 1.00mg/L) in R. philippinarum biochemical (energy reserves, metabolic capacity, oxidative status and neurotoxicity) performance, after 28days of exposure. The results obtained revealed that exposure to MWCNTs altered energy-related responses, with higher metabolic capacity and lower glycogen and protein concentrations in clams exposed to these carbon NPs. Moreover, R. philippinarum exposed to MWCNTs showed oxidative stress expressed in higher lipid peroxidation and lower ratio between reduced and oxidized glutathione, despite the activation of defense mechanisms in exposed clams. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs. The present study provides valuable information regarding how these emerging pollutans could become a potential risk for the environment and living organisms.

      PubDate: 2017-03-20T05:19:36Z
      DOI: 10.1016/j.aquatox.2017.03.010
       
  • Selenium speciation influences bioaccumulation in Limnodynastes peronii
           tadpoles
    • Authors: C.M. Lanctôt; S.D. Melvin; T. Cresswell
      Abstract: Publication date: Available online 12 March 2017
      Source:Aquatic Toxicology
      Author(s): C.M. Lanctôt, S.D. Melvin, T. Cresswell
      Despite being essential for animal health and fitness, Se has a relatively narrow range between deficiency and toxicity, and excess Se can cause a variety of adverse effects in aquatic organisms. Amphibians are particularly vulnerable to contaminants during larval aquatic life stage, because they can accumulate toxic ions through various routes including skin, gills, lungs and digestive tract. Few attempts have been made to understand the tissue-specific accumulation of trace elements, including the impacts of chemical speciation in developing amphibian larvae. We used radiolabelled 75Se to explore the biokinetics and tissue distributions of the two dominant forms occurring in surface waters, selenite (SeIV) and selenate (SeVI). Tadpoles of the native Australian frog Limnodynastes peronii were exposed to Se in both forms, and live-animal gamma spectroscopy was used to track accumulation and retention over time. Tissue biodistributions were also quantified at the end of the uptake and depuration phases. Results showed the bioconcentration of SeIV to be 3 times greater compared to SeVI, but rates of elimination were similar for both forms. This suggests a change of Se speciation within the organism prior to excretion. Depuration kinetics were best described by a one-phase exponential decay model, and tadpoles retained approximately 19% of the accumulated Se after 12 days of depuration in clean water. Selenium bioaccumulation was greatest in digestive and excretory organs, as well as the eye, which may directly relate to previously reported Se-induced impairments. Results demonstrate how the use of radiotracing techniques can significantly improve our understanding of trace element toxicokinetics and tissue distributions in developing amphibians. From an environmental monitoring perspective, the findings highlight the importance of considering chemical speciation as this could influence the accuracy of risk assessment.

      PubDate: 2017-03-15T05:17:10Z
      DOI: 10.1016/j.aquatox.2017.03.009
       
  • The effects of fipronil and the photodegradation product fipronil
           desulfinyl on growth and gene expression in juvenile blue crabs,
           Callinectes sapidus, at different salinities
    • Authors: Andrew D. Goff; Parichehr Saranjampour; Lauren M. Ryan; Michelle L. Hladik; Joseph A. Covi; Kevin L. Armbrust; Susanne M. Brander
      Abstract: Publication date: Available online 28 February 2017
      Source:Aquatic Toxicology
      Author(s): Andrew D. Goff, Parichehr Saranjampour, Lauren M. Ryan, Michelle L. Hladik, Joseph A. Covi, Kevin L. Armbrust, Susanne M. Brander
      Endocrine disrupting compounds (EDCs) are now widely established to be present in the environment at concentrations capable of affecting wild organisms. Although many studies have been conducted in fish, less is known about effects in invertebrates such as decapod crustaceans. Decapods are exposed to low concentrations of EDCs that may cause infertility, decreased growth, and developmental abnormalities. The objective herein was to evaluate effects of fipronil and its photodegradation product fipronil desulfinyl. Fipronil desulfinyl was detected in the eggs of the decapod Callinectes sapidus sampled off the coast of South Carolina. As such, to examine specific effects on C. sapidus exposed in early life, we exposed laboratory-reared juveniles to fipronil and fipronil desulfinyl for 96hours at three nominal concentrations (0.01, 0.1, 0.5μg/L) and two different salinities (10, 30 ppt). The size of individual crabs (weight, carapace width) and the expression of several genes critical to growth and reproduction were evaluated. Exposure to fipronil and fipronil desulfinyl resulted in significant size increases in all treatments compared to controls. Levels of expression for vitellogenin (Vtg), an egg yolk precursor, and the ecdysone receptor (EcR), which binds to ecdysteroids that control molting, were inversely correlated with increasing fipronil and fipronil desulfinyl concentrations. Effects on overall growth and on the expression of EcR and Vtg differ depending on the exposure salinity. The solubility of fipronil is demonstrated to decrease considerably at higher salinities. This suggests that fipronil and its photodegradation products may be more bioavailable to benthic organisms as salinity increases, as more chemical would partition to tissues. Our findings suggest that endocrine disruption is occurring through alterations to gene expression in C. sapidus populations exposed to environmental levels of fipronil, and that effects may be dependent upon the salinity at which exposure occurs.

      PubDate: 2017-03-03T04:58:20Z
      DOI: 10.1016/j.aquatox.2017.02.027
       
  • Toxic effects of 56Fe ion radiation on the zebrafish (Danio rerio)
           embryonic development
    • Authors: Jing Si; Rong Zhou; Jing’e Song; Lu Gan; Xin Zhou; Cuixia Di; Yang Liu; Aihong Mao; Qiuyue Zhao; Yupei Wang; Hong Zhang
      Abstract: Publication date: Available online 28 February 2017
      Source:Aquatic Toxicology
      Author(s): Jing Si, Rong Zhou, Jing’e Song, Lu Gan, Xin Zhou, Cuixia Di, Yang Liu, Aihong Mao, Qiuyue Zhao, Yupei Wang, Hong Zhang
      All living organisms and ecosystems are permanently exposed to ionizing radiation. Of all the types of ionizing radiation, heavy ions such as 56Fe have the potential to cause the most severe biological effects. We therefore examined the effects and potential mechanisms of iron ion irradiation on the induction of developmental toxicity and apoptosis in zebrafish embryos. Zebrafish embryos at 4h post-fertilization (hpf) were divided into five groups: a control group; and four groups irradiated with 0.5, 1, 2, and 4Gy radiation, respectively. Mortality and teratogenesis were significantly increased, and spontaneous movement, heart rate, and swimming distance were decreased in the irradiated groups, accompanied by increased apoptosis. mRNA levels of genes involved in the apoptotic pathway, including p53, bax, bcl-2, and caspase-3, were significantly affected by radiation exposure. Moreover, protein expression levels of P53 and Bcl-2 changed in accordance with the corresponding mRNA expression levels. In addition, we detected the protein expression levels of γ-H2AX, which is a biomarker for radiation-induced DNA double-strand breaks, and found that γ-H2AX protein levels were significantly increased in the irradiated groups. Overall, the results of this study improve our understanding of the mechanisms of iron ion radiation-induced developmental toxicity and apoptosis, potentially involving the induction of DNA damage and mitochondrial dysfunction. The findings of this study may aid future impact assessment of environmental radioactivity in fish.

      PubDate: 2017-03-03T04:58:20Z
      DOI: 10.1016/j.aquatox.2017.02.028
       
  • Effects of food-borne exposure of juvenile rainbow trout (Oncorhynchus
           mykiss) to emerging brominated flame retardants
           1,2-bis(2,4,6-tribromophenoxy)ethane and
           2-ethylhexyl-2,3,4,5-tetrabromobenzoate
    • Authors: Maeva Giraudo; Mélanie Douville; Robert J. Letcher; Magali Houde
      Abstract: Publication date: Available online 22 February 2017
      Source:Aquatic Toxicology
      Author(s): Maeva Giraudo, Mélanie Douville, Robert J. Letcher, Magali Houde
      Brominated flame retardants (BFRs) represent a large group of chemicals used in a variety of household and commercial products to prevent fire propagation. The environmental persistence and toxicity of some of the most widely used BFRs has resulted in a progressive ban worldwide and the development of novel BFRs for which the knowledge on environmental health impacts remains limited. The objectives of this study were to evaluate the effects of two emerging BFRs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), in diet exposed juvenile rainbow trout (Oncorhynchus mykiss). Both compounds were detected in fish carcasses at 76% and 2% of the daily dosage of BTBPE and EH-TBB, respectively, indicating accumulation of BTBPE and by contrast extensive depuration/metabolism of EH-TBB. Liver gene transcription analysis using RNA-sequencing indicated that the chronic 28-d dietary exposure of trout to EH-TBB down-regulated one single gene related to endocrine-mediated processes, whereas BTBPE impacted the transcription of 33 genes, including genes involved in the immune response, reproduction, and oxidative stress. Additional analysis using qRT-PCR after 48-h and 28-d of exposure confirmed the impact of BTBPE on immune related genes in the liver (apolipoprotein A-I, lysozyme) and the head-kidney (complement c3-4). However, the activity of lysozymes measured at the protein level did not reflect transcriptomic results. Overall, results suggested an impact on immune-related gene transcription in BTBPE exposed fish, as well as oxidative stress and endocrine disruption potentials.

      PubDate: 2017-02-24T04:47:03Z
      DOI: 10.1016/j.aquatox.2017.02.023
       
  • Calcium mediates the cellular response of Chlamydomonas reinhardtii to the
           emerging aquatic pollutant Triclosan
    • Authors: Miguel González-Pleiter; Carmen Rioboo; María Reguera; Isidro Abreu; Francisco Leganés; Ángeles Cid; Francisca Fernández-Piñas
      Abstract: Publication date: Available online 22 February 2017
      Source:Aquatic Toxicology
      Author(s): Miguel González-Pleiter, Carmen Rioboo, María Reguera, Isidro Abreu, Francisco Leganés, Ángeles Cid, Francisca Fernández-Piñas
      The present study was aimed at investigating the role of intracellular free calcium, [Ca2+]c, in the early cellular response of the green alga Chlamydomonas reinhardtii to the emergent pollutant Triclosan (13.8μM; 24h of exposure). There is a growing concern about the persistence and toxicity of this antimicrobial in aquatic environments, where non-target organisms such as C. reinhardtii, a primary producer of ecological relevance, might be severely impacted. A mechanistic study was undertaken which combined flow cytometry protocols, physiological as well as gene expression analysis. As an early response, Triclosan strongly altered [Ca2+]c homeostasis which could be prevented by prechelation with the intracellular calcium chelator BAPTA-AM. Triclosan induced ROS overproduction which ultimately leads to oxidative stress with loss of membrane integrity, membrane depolarization, photosynthesis inhibition and mitochondrial membrane depolarization; within this context, Triclosan also induced an increase in caspase 3/7 activity and altered the expression of metacaspase genes which are indicative of apoptosis. All these adverse outcomes were dependent on [Ca2+]c. Interestingly, an interconnection between [Ca2+]c alterations and increased ROS formation by Triclosan was found. Taken altogether these results shed light on the mechanisms behind Triclosan toxicity in the green alga Chlamydomonas reinhardtii and demonstrate the role of [Ca2+]c in mediating the observed toxicity.

      PubDate: 2017-02-24T04:47:03Z
      DOI: 10.1016/j.aquatox.2017.02.021
       
  • Effect of Florfenicol and Thiamphenicol exposure on the photosynthesis and
           antioxidant system of Microcystis flos-aquae
    • Authors: Meixian Wang; Yuxuan Zhang; Peiyong Guo
      Abstract: Publication date: Available online 22 February 2017
      Source:Aquatic Toxicology
      Author(s): Meixian Wang, Yuxuan Zhang, Peiyong Guo
      Florfenicol (FF) and thiamphenicol (TAP) are two typical pharmaceuticals used widely as therapeutica antibiotic agents in aquaculture. However, little is known about the potential adverse effects of these two antibiotics on non-target organisms in the aquatic ecosystem. In this study we investigated the effects of FF and TAP on photosynthesis and the antioxidant system of the cyanobacteria Microcystis flos-aquae. Over a concentration range of 0.001–1μg/L, the results showed that both FF and TAP significantly increased the chlorophyll a content of M. flos-aquae, while the superoxide dismutase (SOD) activity, catalase (CAT) activity and the levels of malondialdehyde (MDA) changed slightly. In contrast, the chlorophyll a content of M. flos-aqua was significantly inhibited (p < 0.01) at high concentrations (> 1μg/L) of FF and TAP, reaching a 46% inhibition level at 50μg/L FF and 56% inhibition at 100μg/L TAP. At the same time, the activities of SOD and CAT along with MDA content also increased significantly (p <0.01), indicating that the high concentrations of both FF and TAP led to oxidative stress in the algae. In addition, the M. flos-aquae fluorescence parameters (Fv/Fm, Fv/Fo, alpha, ETRmax and Ik) increased with increasing concentration of both FF and TAP, which may be the result of the increasing photoprotection capacity.

      PubDate: 2017-02-24T04:47:03Z
      DOI: 10.1016/j.aquatox.2017.02.022
       
  • Toxicological effects of graphene oxide on adult zebrafish (Danio rerio)
    • Authors: Jaqueline P. Souza; Jéssica F. Baretta; Fabrício Santos; Ieda M.M. Paino; Valtencir Zucolotto
      Abstract: Publication date: Available online 16 February 2017
      Source:Aquatic Toxicology
      Author(s): Jaqueline P. Souza, Jéssica F. Baretta, Fabrício Santos, Ieda M.M. Paino, Valtencir Zucolotto
      Graphene exhibits unique physical and chemical properties that facilitate its application in many fields, including electronics and biomedical areas. However, the use of graphene and its derivatives could result in accumulation in aquatic environments, and the risks posed by these compounds for organisms are not completely understood. In this study, we investigated the effects of graphene oxide (GO) on adult zebrafish (Danio rerio). Experimental fish were exposed to 2, 10 or 20mg L−1 GO, and the cytotoxicity, genotoxicity and oxidative stress were assessed. The morphology of the gills and liver tissues was also analyzed. Graphene oxide exposure led to an increase in the number of gill cells that were in early apoptotic and necrotic stages, but genotoxicity was not observed in blood cells. We also observed the generation of Reactive Oxygen Species (ROS) in gill cells. Structural analysis revealed injuries to gill tissues, including a dilated marginal channel, lamellar fusion, clubbed tips, swollen mucocytes, epithelial lifting, aneurysms, and necrosis. Liver tissues also presented lesions such as peripherally located nuclei. Furthermore, hepatocytes exhibited a non-uniform shape, picnotic nuclei, vacuole formation, cell rupture, and necrosis. Our results showed that sub-lethal doses of graphene oxide could be harmful to fish species and thus represent risks for the aquatic food chain.

      PubDate: 2017-02-17T04:35:13Z
      DOI: 10.1016/j.aquatox.2017.02.017
       
  • Characterisation of the transcriptome of male and female wild-type guppy
           brains with RNA-Seq and consequences of exposure to the pharmaceutical
           pollutant, 17α-ethinyl estradiol
    • Authors: Minna Saaristo; Bob B.M. Wong; Laura Mincarelli; Allison Craig; Christopher P. Johnstone; Mayumi Allinson; Kai Lindström; John A. Craft
      Abstract: Publication date: Available online 16 February 2017
      Source:Aquatic Toxicology
      Author(s): Minna Saaristo, Bob B.M. Wong, Laura Mincarelli, Allison Craig, Christopher P. Johnstone, Mayumi Allinson, Kai Lindström, John A. Craft
      Waterways are increasingly being contaminated by chemical compounds that can disrupt the endocrinology of organisms. One such compound is 17α-ethinyl estradiol (EE2), a synthetic estrogen used in the contraceptive pill. Despite considerable research interest in the effects of EE2 on reproduction and gene expression, surprisingly, only a few studies have capitalised on technologies, such as next-generation sequencing (NGS), to uncover the molecular pathways related to EE2 exposure. Accordingly, using high-throughput sequencing technologies, the aim of our study was to explore the effects of EE2 on brain transcriptome in wild-type male and female guppy (Poecilia reticulata). We conducted two sets of experiments, where fish were exposed to EE2 (measured concentrations: 8ng/L and 38ng/L) in a flow-through system for 21 days. The effects on the brain transcriptome on both males and females were assessed using Illumina sequencing (MiSeq and HiSeq) platform followed by bioinformatics analysis (edgeR, DESeq2). Here, we report that exposure to EE2 caused both up- and downregulation of specific transcript abundances, and affected transcript abundance in a sex-specific manner. Specifically, we found 773 transcripts, of which 60 were male-specific, 61 female-specific and 285 treatment-specific. EE2 affected expression of 165 transcripts in males, with 88 downregulated and 77 upregulated, while in females, 120 transcripts were affected with 62 downregulated and 58 upregulated. Finally, RT-qPCR validation demonstrated that expression of transcripts related to transposable elements, neuroserpin and heat shock protein were significantly affected by EE2-exposure. Our study is the first to report brain transcriptome libraries for guppies exposed to EE2. Not only does our study provide a valuable resource, it offers insights into the mechanisms underlying the feminizing effects on the brains of organisms exposed to environmentally realistic concentrations of EE2.

      PubDate: 2017-02-17T04:35:13Z
      DOI: 10.1016/j.aquatox.2017.02.016
       
 
 
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