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  Subjects -> BIOLOGY (Total: 3149 journals)
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    - BIOLOGY (1495 journals)
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    - ZOOLOGY (137 journals)

BIOLOGY (1495 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 22)
Achievements in the Life Sciences     Open Access   (Followers: 5)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 24)
Acta Biologica Colombiana     Open Access   (Followers: 7)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 4)
Acta Biologica Sibirica     Open Access  
Acta Biomaterialia     Hybrid Journal   (Followers: 27)
Acta Biotheoretica     Hybrid Journal   (Followers: 4)
Acta Chiropterologica     Full-text available via subscription   (Followers: 6)
acta ethologica     Hybrid Journal   (Followers: 4)
Acta Limnologica Brasiliensia     Open Access   (Followers: 3)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Musei Silesiae, Scientiae Naturales : The Journal of Silesian Museum in Opava     Open Access  
Acta Neurobiologiae Experimentalis     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 10)
Acta Scientiarum. Biological Sciences     Open Access   (Followers: 2)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis     Open Access  
Actualidades Biológicas     Open Access   (Followers: 1)
Advanced Health Care Technologies     Open Access   (Followers: 4)
Advanced Journal of Graduate Research     Open Access  
Advanced Studies in Biology     Open Access  
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Bioinformatics     Open Access   (Followers: 17)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4)
Advances in Biology     Open Access   (Followers: 8)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 7)
Advances in Cell Biology     Open Access   (Followers: 25)
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: 42)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 17)
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: 8)
Advances in High Energy Physics     Open Access   (Followers: 18)
Advances in Human Biology     Open Access   (Followers: 3)
Advances in Life Science and Technology     Open Access   (Followers: 16)
Advances in Life Sciences     Open Access   (Followers: 6)
Advances in Marine Biology     Full-text available via subscription   (Followers: 14)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3)
Advances in Regenerative Biology     Open Access   (Followers: 1)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Virus Research     Full-text available via subscription   (Followers: 5)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 6)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 1)
Ageing Research Reviews     Hybrid Journal   (Followers: 10)
Aging Cell     Open Access   (Followers: 12)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
AJP Cell Physiology     Full-text available via subscription   (Followers: 14)
AJP Endocrinology and Metabolism     Full-text available via subscription   (Followers: 23)
AJP Lung Cellular and Molecular Physiology     Full-text available via subscription   (Followers: 3)
Al-Kauniyah : Jurnal Biologi     Open Access  
Alasbimn Journal     Open Access   (Followers: 1)
Alces : A Journal Devoted to the Biology and Management of Moose     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Biology Teacher     Full-text available via subscription   (Followers: 14)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 8)
American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Human Biology     Hybrid Journal   (Followers: 13)
American Journal of Medical and Biological Research     Open Access   (Followers: 8)
American Journal of Plant Sciences     Open Access   (Followers: 18)
American Journal of Primatology     Hybrid Journal   (Followers: 14)
American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 70)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anadolu University Journal of Science and Technology : C Life Sciences and Biotechnology     Open Access  
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 10)
Anatomical Science International     Hybrid Journal   (Followers: 2)
Animal Cells and Systems     Hybrid Journal   (Followers: 4)
Annales de Limnologie - International Journal of Limnology     Hybrid Journal   (Followers: 1)
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales UMCS, Biologia     Open Access   (Followers: 1)
Annals of Applied Biology     Hybrid Journal   (Followers: 7)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18)
Annals of Human Biology     Hybrid Journal   (Followers: 5)
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 15)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 23)
Annual Review of Cancer Biology     Full-text available via subscription   (Followers: 1)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 37)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 23)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 23)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antibiotics     Open Access   (Followers: 9)
Antioxidants     Open Access   (Followers: 4)
Antioxidants & Redox Signaling     Hybrid Journal   (Followers: 8)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apidologie     Hybrid Journal   (Followers: 4)
Apmis     Hybrid Journal   (Followers: 1)
APOPTOSIS     Hybrid Journal   (Followers: 8)
Applied Bionics and Biomechanics     Open Access   (Followers: 8)
Applied Vegetation Science     Full-text available via subscription   (Followers: 10)
Aquaculture Environment Interactions     Open Access   (Followers: 2)
Aquaculture International     Hybrid Journal   (Followers: 22)
Aquaculture Reports     Open Access   (Followers: 3)
Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society     Open Access   (Followers: 6)
Aquatic Biology     Open Access   (Followers: 5)
Aquatic Ecology     Hybrid Journal   (Followers: 33)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 14)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 21)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biological Sciences     Open Access  
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Archives of Natural History     Hybrid Journal   (Followers: 6)
Archives of Oral Biology     Hybrid Journal   (Followers: 2)
Archives of Virology     Hybrid Journal   (Followers: 5)
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2)
Arid Ecosystems     Hybrid Journal   (Followers: 2)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arquivos do Museu Dinâmico Interdisciplinar     Open Access  
Arthropod Structure & Development     Hybrid Journal   (Followers: 2)
Arthropods     Open Access   (Followers: 1)
Artificial DNA: PNA & XNA     Hybrid Journal   (Followers: 3)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 3)
Asian Journal of Biodiversity     Open Access   (Followers: 4)
Asian Journal of Biological Sciences     Open Access   (Followers: 3)
Asian Journal of Cell Biology     Open Access   (Followers: 5)
Asian Journal of Developmental Biology     Open Access   (Followers: 2)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 3)
Asian Journal of Nematology     Open Access   (Followers: 4)
Asian Journal of Poultry Science     Open Access   (Followers: 3)
Atti della Accademia Peloritana dei Pericolanti - Classe di Scienze Medico-Biologiche     Open Access  
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 6)
Autophagy     Hybrid Journal   (Followers: 2)
Avian Biology Research     Full-text available via subscription   (Followers: 4)
Avian Conservation and Ecology     Open Access   (Followers: 11)
Bacteriology Journal     Open Access   (Followers: 1)
Bacteriophage     Full-text available via subscription   (Followers: 3)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Plant Taxonomy     Open Access  
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Batman Üniversitesi Yaşam Bilimleri Dergisi     Open Access  
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)
BioCentury Innovations     Full-text available via subscription   (Followers: 1)
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 15)
Biochimie     Hybrid Journal   (Followers: 7)
BioControl     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodemography and Social Biology     Hybrid Journal  
BioDiscovery     Open Access   (Followers: 2)
Biodiversitas : Journal of Biological Diversity     Open Access  
Biodiversity : Research and Conservation     Open Access   (Followers: 26)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     Open Access   (Followers: 1)
Biodiversity Information Science and Standards     Open Access  
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Bioelectromagnetics     Hybrid Journal   (Followers: 1)
Bioenergy Research     Hybrid Journal   (Followers: 2)
Bioengineering and Bioscience     Open Access   (Followers: 1)
BioEssays     Hybrid Journal   (Followers: 10)
Bioethics     Hybrid Journal   (Followers: 14)
BioéthiqueOnline     Open Access  
Biofabrication     Hybrid Journal   (Followers: 5)
Biofilms     Full-text available via subscription   (Followers: 1)
Biogeosciences (BG)     Open Access   (Followers: 10)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 2)
Bioinformatics     Hybrid Journal   (Followers: 293)
Bioinformatics and Biology Insights     Open Access   (Followers: 11)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 7)
Biointerphases     Open Access   (Followers: 1)
Biojournal of Science and Technology     Open Access  
Biologia     Hybrid Journal  
Biologia on-line : Revista de divulgació de la Facultat de Biologia     Open Access  
Biological Bulletin     Partially Free   (Followers: 6)
Biological Control     Hybrid Journal   (Followers: 4)
Biological Invasions     Hybrid Journal   (Followers: 19)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 18)
Biological Letters     Open Access   (Followers: 5)
Biological Procedures Online     Open Access  
Biological Psychiatry     Hybrid Journal   (Followers: 46)
Biological Psychology     Hybrid Journal   (Followers: 7)
Biological Research     Open Access  
Biological Rhythm Research     Hybrid Journal   (Followers: 2)
Biological Theory     Hybrid Journal   (Followers: 2)
Biological Trace Element Research     Hybrid Journal  

        1 2 3 4 5 6 7 8 | Last

Journal Cover
Aquatic Toxicology
Journal Prestige (SJR): 1.456
Citation Impact (citeScore): 4
Number of Followers: 21  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0166-445X - ISSN (Online) 1879-1514
Published by Elsevier Homepage  [3163 journals]
  • Genome-wide identification of 99 autophagy-related (Atg) genes in the
           monogonont rotifer Brachionus spp. and transcriptional modulation in
           response to cadmium
    • Authors: Hye-Min Kang; Jin-Sol Lee; Min-Sub Kim; Young Hwan Lee; Jee-Hyun Jung; Atsushi Hagiwara; Bingsheng Zhou; Jae-Seong Lee; Chang-Bum Jeong
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Hye-Min Kang, Jin-Sol Lee, Min-Sub Kim, Young Hwan Lee, Jee-Hyun Jung, Atsushi Hagiwara, Bingsheng Zhou, Jae-Seong Lee, Chang-Bum Jeong
      Autophagy originated from the common ancestor of all life forms, and its function is highly conserved from yeast to humans. Autophagy plays a key role in various fundamental biological processes including defense, and has developed through serial interactions of multiple gene sets referred to as autophagy-related (Atg) genes. Despite their significance in metazoan life and evolution, few studies have been conducted to identify these genes in aquatic invertebrates. In this study, we identified whole Atg genes in four Brachionus rotifer spp., namely B. calyciflorus, B. koreanus, B. plicatilis, and B. rotundiformis, through searches of their entire genomes; and we annotated them according to the yeast nomenclature. Twenty-four genes orthologous to yeast genes were present in all of the Brachionus spp. while three additional gene duplicates were identified in the genome of B. koreanus, indicating that these genes had diversified during the speciation. Also, their transcriptional responses to cadmium exposure indicated regulation by cadmium-induced oxidative-stress–related signaling pathways. This study provides valuable information on 99 conserved Atg genes involved in autophagosome formation in Brachionus spp., with transcriptional modulation in response to cadmium, in the context of the role of autophagy in the damage response.

      PubDate: 2018-06-07T10:40:01Z
      DOI: 10.1016/j.aquatox.2018.05.021
      Issue No: Vol. 201 (2018)
       
  • Can the inhibition of cytochrome P450 in aquatic invertebrates due to
           azole fungicides be estimated with in silico and in vitro models and
           extrapolated between species'
    • Authors: Michele Gottardi; Jonathan D. Tyzack; Andreas Bender; Nina Cedergreen
      Pages: 11 - 20
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Michele Gottardi, Jonathan D. Tyzack, Andreas Bender, Nina Cedergreen
      Azole fungicides, designed to halt fungal growth by specific inhibition of fungal cytochrome P450 (CYP51), inhibit cytochrome P450s involved in the metabolism of xenobiotics in several non-target organisms thus raising environmental concern. The present study investigates the degree by which inhibition strengths of azoles toward cytochrome P450 in rat liver, the insect Chironomus riparius larvae and the snail Lymnaea stagnalis can be extrapolated from estimated in silico affinities. Azoles’ affinities toward human cytochrome P450 isoforms involved in xenobiotic metabolism (CYP3A4, CYP2C9 and CYP2D6) as well as fungal CYP51 were estimated with a ligand-protein docking model based on the ChemScore scoring function. Estimated affinities toward the selected enzymatic structures correlated strongly with measured inhibition strengths in rat liver (ChemScore vs. logIC50 among cytochrome P450 isoforms: −0.662 < r < −0.891, n = 17 azoles), while weaker correlations were found for C. riparius larvae (−0.167 < r < −0.733, n = 9) and L. stagnalis (−0.084 < r < −0.648, n = 8). Inhibition strengths toward C. riparius and rat liver activities were found to be highly correlated to each other (r: 0.857) while no significant relationship was found between either of the species and L. stagnalis. The inhibition of cytochrome P450 due to azole fungicides could be estimated in vitro and to a lesser extent in silico for C. riparius but not for L. stagnalis, possibly due to different enzymatic susceptibility toward azole inhibition among the species.

      PubDate: 2018-05-31T21:30:36Z
      DOI: 10.1016/j.aquatox.2018.05.017
      Issue No: Vol. 201 (2018)
       
  • Dose- and age-specific antioxidant responses of the mysid crustacean
           Neomysis awatschensis to metal exposure
    • Authors: Md. Niamul Haque; Do-Hee Lee; Bo-Mi Kim; Sang-Eun Nam; Jae-Sung Rhee
      Pages: 21 - 30
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Md. Niamul Haque, Do-Hee Lee, Bo-Mi Kim, Sang-Eun Nam, Jae-Sung Rhee
      Waterborne metals can adversely affect an organism’s innate defenses through oxidative stress. In the present study, the marine mysid Neomysis awatchensis was exposed to sublethal concentrations (1/10 and 1/5 of the median LC50s) of As, Cd, Cu, Pb, and Zn for 48 or 96 h at the juvenile and adult developmental stages, and the dose- and age-specific antioxidant defense system responses were characterized. Metal accumulation and modulation of four key antioxidant biomarkers, malondialdehyde (MDA), glutathione (GSH), superoxide dismutase, and catalase, were measured in juvenile and adult mysids. Based on LC50, level of metal toxicity was dependent on metal concentration, developmental stage, and the exposure duration. Intracellular MDA content was increased in the As-, Cu-, Pb-, and Zn-exposed juvenile mysids after exposure for 48 and/or 96 h, while increases in MDA content were observed in adult mysids following Cu and Zn exposure. Interestingly, GSH content was differentially modulated, where intracellular GSH levels decreased in juvenile mysids following Cd, Cu, Pb, and Zn exposure, but significantly increased in metal-exposed adult mysids, except for Pb exposure. The catalase and superoxide dismutase activities displayed similar stage-specific increases or decreases as also observed for the different GSH levels, suggesting that the susceptibility to and defense against metal-induced oxidative stress differed based on stage. Modulations in MDA and GSH content and enzymatic activity of the antioxidant defense system indicate that mysid antioxidant defense system factors are intimately connected during control of oxidative imbalances with different capacities at different developmental stages.

      PubDate: 2018-05-31T21:30:36Z
      DOI: 10.1016/j.aquatox.2018.05.023
      Issue No: Vol. 201 (2018)
       
  • The progestin norethindrone affects sex differentiation and alters
           transcriptional profiles of genes along the
           hypothalamic–pituitary–gonadal and hypothalamic–pituitary–adrenal
           axes in juvenile zebrafish Dario renio
    • Authors: Li-ping Hou; Hongxing Chen; Chang-en Tian; Wen-Jun Shi; Ye Liang; Rong-rong Wu; Xu-wen Fang; Cui-ping Zhang; Yan-qiu Liang; Lingtian Xie
      Pages: 31 - 39
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Li-ping Hou, Hongxing Chen, Chang-en Tian, Wen-Jun Shi, Ye Liang, Rong-rong Wu, Xu-wen Fang, Cui-ping Zhang, Yan-qiu Liang, Lingtian Xie
      Natural and synthetic progestins may pose a threat to wild fish populations living in receiving waters. In this study, the effects of norethindrone (NET) on the sex differentiation of zebrafish (Dario renio) and the mechanisms underlying these effects were investigated. Juvenile zebrafish (20 days post fertilization, pdf) were exposed to environmentally relevant concentrations (5, 50, 500, and 1000 ng L−1) for 45 d. Sex ratio of the NET-exposed populations, the histology of the gonads and the transcriptional profile of the regulatory genes involved in sex differentiation and steroidogenesis were examined. The results showed that a significantly higher ratio of male/female was induced in the zebrafish populations exposed to NET at concentrations higher than 32.3 ng L−1. Exposure to NET caused acceleration of sexual mature in males and a delay in ovary maturation in female zebrafish. Among the genes regulating sexual differentiation, transcripts of Dmrt1 showed a dose-dependent increase while transcripts of Figa and Fox12 showed a dose-dependent decrease in response to exposure to NET. For genes regulating the steroidogenesis, the expressions of Cyp11a1, Cyp17, Cyp19a1a, and Cyp11b were significantly down-regulated by exposure to NET, while Hsd17b3 expression was significantly up-regulated by exposure to NET at 421.3 and 892.9 ng L−1. For the receptor genes in the gonads, the transcriptional expression of Pgr, Ar, and Mr was significantly up-regulated at 421.3 and 892.9 ng L−1 of NET. For genes involved in the hypothalamic–pituitary axis, the transcriptional expression of Gnrh3 and Pomc was significantly up-regulated by exposure to NET with the exception for Gnrh3 at 4.2 ng L−1. The results demonstrated that exposure to NET at the juvenile stage could affect gonad differentiation and sex ratio, which might be accounted for by the alterations of the transcriptional expressions of genes along the hypothalamic–pituitary–gonadal (HPG) and hypothalamic–pituitary–adrenal (HPA) axes.

      PubDate: 2018-05-31T21:30:36Z
      DOI: 10.1016/j.aquatox.2018.05.019
      Issue No: Vol. 201 (2018)
       
  • Retrospective analyses of archive phytotoxicity test data can help in
           assessing internal dynamics and stability of growth in laboratory duckweed
           cultures
    • Authors: Viktor Oláh; Anna Hepp; Norma Yolanda Gaibor Vaca; Marianna Tamás; Ilona Mészáros
      Pages: 40 - 46
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Viktor Oláh, Anna Hepp, Norma Yolanda Gaibor Vaca, Marianna Tamás, Ilona Mészáros
      High growth potential of duckweed species (Lemnaceae family) has been utilized in wide range of research and practical applications. Based on literature data, however, it can be assumed that duckweed populations maintain constant growth rates only when short periods are considered but can vary over longer time scales. This intrinsic instability in growth can affect the interpretation of growth data. Duckweed phytotoxicity tests are usually performed according to highly standardized protocols. Therefore the archive data provide an opportunity for retrospective comparisons. In the present study we collected growth (frond number- and frond area-based relative growth rates) and morphology (average frond and colony sizes) data from control treatments of phytotoxicity tests. All the analyzed tests were carried out with the same Spirodela polyrhiza (L.) Schleid. (giant duckweed) clone (RDSC ID No. 5501) under the same experimental conditions over more than four years. We aimed to assess the overall variability of the above parameters and to test if intrinsic growth patterns affect growth data in short-term. In general, the results reflected high stability of the measured parameters in long term but also indicated that some temporal variability is inevitable which can bias the comparability of growth tests. The frond area-based relative growth rate resulted in smaller coefficient of variation than the usually preferred frond number-based one. The results also revealed a negative correlation between mean growth rates and their coefficients of variation. Therefore, it would be advisable to introduce higher minimal growth rates and/or maximized tolerable coefficients of variation for control cultures into the standard duckweed growth inhibition tests. Analyses of growth data aggregated on seasonal basis indicated faster growth and larger mean frond size in laboratory duckweed cultures from mid-autumn till mid-spring than during summer and early autumn. But, in shorter term (∼50 days) we did not observe distinct trends in growth suggesting that the successive frond generations have no effect on growth traits within this time-scale. Our results point to the importance of assessing intrinsic growth dynamics in duckweed cultures and also to the re-usability of the already collected phytotoxicity data in addressing new research questions.

      PubDate: 2018-05-31T21:30:36Z
      DOI: 10.1016/j.aquatox.2018.05.022
      Issue No: Vol. 201 (2018)
       
  • Styrene impairs normal embryo development in the Mediterranean mussel
           (Mytilus galloprovincialis)
    • Authors: Rajapaksha Haddokara Gedara Rasika Wathsala; Silvia Franzellitti; Morena Scaglione; Elena Fabbri
      Pages: 58 - 65
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Rajapaksha Haddokara Gedara Rasika Wathsala, Silvia Franzellitti, Morena Scaglione, Elena Fabbri
      This study analysed the effects of styrene, a main monomer in plastic manufacturing and acknowledged to be amongst the most common plastic leachates, on early embryo development of the Mediterranean mussel. Embryotoxicity tests showed that styrene impaired normal embryo development at concentrations (0.01 μg/L–1 mg/L) encompassing the environmental range. Occurrence of normal D-veligers was significantly reduced up to 40% of the total, and larval size was reduced of about 20%. D-veligers grown in the presence of styrene (0.1 and 10 μg/L) showed significant reduction of total Multixenobiotic resistance (MXR) efflux activity that was not apparently related to transcriptional expression of genes encoding P-glycoprotein (ABCB) and Mrp (ABCC), the two main ABC transporters of embryonal MXR system. Indeed, ABCB transcription was not affected by styrene, while ABCC was up-regulated. At these same concentrations, transcriptional profiles of 15 genes underlying key biological functions in embryo development and potential targets of adverse effects of styrene were analysed. Main transcriptional effects were observed for genes involved in shell biogenesis and lysosomal responses (down-regulation), and in neuroendocrine signaling and immune responses (up-regulation). On the whole, results indicate that styrene may affect mussel early development through dysregulation of gene transcription and suggest the possible conservation of styrene mode of action across bivalve life cycle and between bivalves and humans, as well as through unpredicted impacts on protective systems and on shell biogenesis.

      PubDate: 2018-06-04T10:36:41Z
      DOI: 10.1016/j.aquatox.2018.05.026
      Issue No: Vol. 201 (2018)
       
  • Comparative toxicity of three phenolic compounds on the embryo of fathead
           minnow, Pimephales promelas
    • Authors: Erchao Li; Derek G. Bolser; Kevin J. Kroll; Erica K. Brockmeier; Francesco Falciani; Nancy D. Denslow
      Pages: 66 - 72
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Erchao Li, Derek G. Bolser, Kevin J. Kroll, Erica K. Brockmeier, Francesco Falciani, Nancy D. Denslow
      Phenols are classified as polar narcotics, which are thought to cause toxicity by non-specific mechanisms, possibly by disrupting membrane structure and function. Here we test three phenolic chemicals, phenol, 2,4-dichlorphenol and pentachlorophenol on embryo development, heartbeat rate and mitochondrial respiration in fathead minnow (Pimephales promelas). While these chemicals have been used on isolated mitochondria, they have not yet been used to verify respiration in intact embryos. Mitochondrial respiration in intact embryos was measured after optimizing the Seahorse XFe24 Extracellular Flux Analyzer. Heartbeat rate and mitochondrial respiration patterns of fathead minnow embryos at different developmental stages were also characterized. Exposures of embryos at developmental stage 20 occurred for 24 h with five concentrations of each phenolic compound ranging from 0.85 to 255 μM for phenol, 0.49 to 147 μM for 2,4-dichlorophenol and 0.3 to 90 μM for pentachlorophenol. Exposure to phenol at the concentrations tested had no effects on development, heartbeat or mitochondrial respiration. However, both 2,4-dichlorophenol and pentachlorophenol showed dose-dependent effects on development, heartbeat rate, and mitochondrial respiration, with the effects occurring at lower concentrations of pentachlorophenol, compared to 2,4-dichlorophenol, highlighting the higher toxicity of the more chlorinated phenols. Both 2,4-dichlorophenol and pentachlorophenol decreased basal mitochondrial respiration of embryos and ATP production. These results indicate that higher chlorinated phenolic chemicals cause developmental toxicity in fathead minnow embryos by decreasing mitochondrial respiration and heartbeat rate.

      PubDate: 2018-06-07T10:40:01Z
      DOI: 10.1016/j.aquatox.2018.05.024
      Issue No: Vol. 201 (2018)
       
  • Comparative effects of cadmium, zinc, arsenic and chromium on
           olfactory-mediated neurobehavior and gene expression in larval zebrafish
           (Danio rerio)
    • Authors: Kevin Heffern; Keith Tierney; Evan P. Gallagher
      Pages: 83 - 90
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Kevin Heffern, Keith Tierney, Evan P. Gallagher
      Studies have shown that olfactory-mediated behaviors that are critical to survival can be disrupted by exposure to certain metals. Polluted waterways often contain elevated levels of metals, yet only a subset have been characterized for their potential to cause olfactory toxicity. A larval zebrafish behavioral assay was developed to characterize concentration-response curves for zinc (Zn), hexavalent chromium (Cr), and arsenate (As) olfaction inhibition. Cadmium (Cd), an established olfactory toxicant, was used as a positive control. As expected, following a 24-hour exposure to Cd, we observed a reduced response to taurocholic acid (TCA), a substrate for ciliated olfactory sensory neurons (OSNs), thus validating the behavioral assay. Zn exposure similarly decreased the olfactory response toward TCA, (IC50: 36 μg/L and 76 μg/L, for Cd and Zn, respectively). The response towards a secondary odorant L-cysteine (Cys), a substrate for ciliated and microvillous OSNs, was significantly altered by both Cd and Zn exposure, although the response to Cys was not completely removed in Zn treated larvae, suggesting preferential toxicity towards ciliated OSNs. No significant changes in olfactory responses were observed following Cr and As exposures. Exposures to binary mixtures of Cd and Zn indicated that Zn had a protective effect against Cd toxicity at low Zn concentrations. QuantiGene (QDP) RNA analysis revealed Cd to be a potent inducer of metallothionein 2 (mt2) mRNA in zebrafish larvae, and Zn to be a weak mt2 inducer, suggesting a protective role of mt2 in Cd and Zn olfactory injury. By contrast, QDP analysis of eight other genes important in mitigating the effects of oxidative stress suggested an antioxidant response to Cd, but not Zn, As, and Cr suggesting that oxidative stress was not a primary mechanism of Zn-induced olfactory dysfunction. In summary, our study indicates that Zn inhibits zebrafish olfaction at environmental concentrations and may potentially mitigate Cd induced olfactory dysfunction when present in mixtures. The zebrafish behavioral trough assay incorporating the odorants L-cysteine and TCA is an effective assay to assess the effects of metals on olfactory function.

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.05.016
      Issue No: Vol. 201 (2018)
       
  • Phosphate alleviation of glyphosate-induced toxicity in Hydrocharis dubia
           (Bl.) Backer
    • Authors: Guidi Zhong; Zhonghua Wu; Nian Liu; Jun Yin
      Pages: 91 - 98
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Guidi Zhong, Zhonghua Wu, Nian Liu, Jun Yin
      Glyphosate, as a broad-spectrum herbicide, is frequently detected in water, and phosphorus widely enters the water due to the extensive use of phosphorus-containing substances in agriculture, industries and daily life. Thus, aquatic ecosystems are exposed to both glyphosate and phosphorus, which may affect aquatic organisms. In the present research, we studied the physiological responses of the floating aquatic plant species H. dubia to different concentrations of glyphosate (0, 1, 5, 15 mg/L) with different levels of phosphate (0, 50, 100 mg/L) after 14 days (d) of treatment. We explored glyphosate toxicity in H. dubia and investigated whether phosphate addition mitigates glyphosate toxicity in this species, which will provide a theoretical basis for the ecotoxicological study of aquatic plants. The results show that glyphosate significantly reduced the chlorophyll content, leaf number and root length of H. dubia, while it significantly increased the malondialdehyde (MDA), hydrogen peroxide (H2O2), shikimate, proline, and soluble protein content and enzyme activities (superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and polyphenol oxidase (PPO)) in H. dubia. After phosphate supplement, the MDA, H2O2, proline, and soluble protein contents and enzyme activities in the plants treated with glyphosate decreased. These results indicate that the concentration of glyphosate investigated in our study can cause oxidative stress and affect the growth of H. dubia. Phosphate can alleviate glyphosate-induced oxidative stress in H. dubia.

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.05.025
      Issue No: Vol. 201 (2018)
       
  • An AOP-based alternative testing strategy to predict the impact of thyroid
           hormone disruption on swim bladder inflation in zebrafish
    • Authors: Evelyn Stinckens; Lucia Vergauwen; Gerald T. Ankley; Ronny Blust; Veerle M. Darras; Daniel L. Villeneuve; Hilda Witters; David C. Volz; Dries Knapen
      Pages: 1 - 12
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Evelyn Stinckens, Lucia Vergauwen, Gerald T. Ankley, Ronny Blust, Veerle M. Darras, Daniel L. Villeneuve, Hilda Witters, David C. Volz, Dries Knapen
      The adverse outcome pathway (AOP) framework can be used to help support the development of alternative testing strategies aimed at predicting adverse outcomes caused by triggering specific toxicity pathways. In this paper, we present a case-study demonstrating the selection of alternative in chemico assays targeting the molecular initiating events of established AOPs, and evaluate use of the resulting data to predict higher level biological endpoints. Based on two AOPs linking inhibition of the deiodinase (DIO) enzymes to impaired posterior swim bladder inflation in fish, we used in chemico enzyme inhibition assays to measure the molecular initiating events for an array of 51 chemicals. Zebrafish embryos were then exposed to 14 compounds with different measured inhibition potentials. Effects on posterior swim bladder inflation, predicted based on the information captured by the AOPs, were evaluated. By linking the two datasets and setting thresholds, we were able to demonstrate that the in chemico dataset can be used to predict biological effects on posterior chamber inflation, with only two outliers out of the 14 tested compounds. Our results show how information organized using the AOP framework can be employed to develop or select alternative assays, and successfully forecast downstream key events along the AOP. In general, such in chemico assays could serve as a first-tier high-throughput system to screen and prioritize chemicals for subsequent acute and chronic fish testing, potentially reducing the need for long-term and costly toxicity tests requiring large numbers of animals.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.009
      Issue No: Vol. 200 (2018)
       
  • Cytotoxicity of CeO2 nanoparticles using in vitro assay with Mytilus
           galloprovincialis hemocytes: Relevance of zeta potential, shape and
           biocorona formation
    • Authors: M. Sendra; M. Volland; T. Balbi; R. Fabbri; M.P. Yeste; J.M. Gatica; L. Canesi; J. Blasco
      Pages: 13 - 20
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): M. Sendra, M. Volland, T. Balbi, R. Fabbri, M.P. Yeste, J.M. Gatica, L. Canesi, J. Blasco
      Over the last decades, the growth in nanotechnology has provoked an increase in the number of its applications and consumer products that incorporate nanomaterials in their formulation. Metal nanoparticles are released to the marine environment and they can interact with cells by colloids forces establish a nano-bio interface. This interface can be compatible or generate bioadverse effects to cells. The daily use of CeO2 nanoparticles (CeO2 NPs) in industrial catalysis, sunscreen, fuel cells, fuel additives and biomedicine and their potential release into aquatic environments has turned them into a new emerging pollutant of concern. It is necessary to assess of effects of CeO2 NPs in aquatic organisms and understand the potential mechanisms of action of CeO2 NP toxicity to improve our knowledge about the intrinsic and extrinsic characteristic of CeO2 NPs and the interaction of CeO2 NPs with biomolecules in different environment and biological fluids. The conserved innate immune system of bivalves represents a useful tool for studying immunoregulatory responses when cells are exposed to NPs. In this context, the effects of two different CeO2 NPs with different physico-chemical characteristics (size, shape, zeta potential and Ce+3/Ce+4 ratio) and different behavior with biomolecules in plasma fluid were studied in a series of in vitro assays using primary hemocytes from Mytilus galloprovincialis. Different cellular responses such as lysosome membrane stability, phagocytosis capacity and extracellular reactive oxygen species (ROS) production were evaluated. Our results indicate that the agglomeration state of CeO2 NPs in the exposure media did not appear to have a substantial role in particle effects, while differences in shape, zeta potential and biocorona formation in NPs appear to be important in provoking negative impacts on hemocytes. The negative charge and the rounded shape of CeO2 NPs, which formed Cu, Zn-SOD biocorona in hemolymph serum (HS), triggered higher changes in the biomarker of stress (LMS) and immunological parameters (ROS and phagocytosis capacity). On the other hand, the almost neutral surface charge and well-faceted shape of CeO2 NPs did not show either biocorona formation in HS under tested conditions or significant responses. According to the results, the most relevant conclusion of this work is that not only the physicochemical characterization of CeO2 NPs plays an important role in NPs toxicity but also the study of the interaction of NPs with biological fluids is essential to know it behavior and toxicity at cellular level.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.011
      Issue No: Vol. 200 (2018)
       
  • Role of endocytotic uptake routes in impacting the ROS-related toxicity of
           silver nanoparticles to Mytilus galloprovincialis: A redox proteomic
           investigation
    • Authors: Younes Bouallegui; Ridha Ben Younes; Ridha Oueslati; David Sheehan
      Pages: 21 - 27
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Younes Bouallegui, Ridha Ben Younes, Ridha Oueslati, David Sheehan
      Oxidative stress is often implicated in nanoparticle toxicity. Several studies have highlighted the role of internalization routes in determining nanotoxicity. Here, we investigate how two endocytotic mechanisms (clathrin- and caveolae-mediated) impact on redox balance in gill and digestive gland of the mussel, Mytilus galloprovincialis. Animals were exposed (for 3, 6 and 12 h) to two sizes of silver nanoparticles (AgNP: <50 nm and <100 nm) prior to and after blockade of two endocytic pathways (amantadine blocks clathrin-mediated endocytosis while nystatin blocks caveolae-mediated endocytosis). Redox-proteomic tools were used to determine effects. Our results demonstrate the ability of both sizes of AgNP (<50 and <100 nm) to cause protein thiol oxidation and/or protein carbonylation. However, blockade of endocytotic routes mitigated AgNP toxicity. Differential ROS-related toxicity of AgNP to mussel tissues seemed to be linked to tissue-specific mode of action requirements. Cell uptake mechanism strongly influences toxicity of AgNPs in this filter-feeder.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.013
      Issue No: Vol. 200 (2018)
       
  • Accumulation of polystyrene microplastics in juvenile Eriocheir sinensis
           and oxidative stress effects in the liver
    • Authors: Ping Yu; Zhiquan Liu; Donglei Wu; Minghai Chen; Weiwei Lv; Yunlong Zhao
      Pages: 28 - 36
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Ping Yu, Zhiquan Liu, Donglei Wu, Minghai Chen, Weiwei Lv, Yunlong Zhao
      As a widespread and ubiquitous pollutant of marine ecosystems, microplastic has the potential to become an emerging global threat for aquatic organisms. The present study aims to elucidate the effects of microplastics on the growth, accumulation and oxidative stress response in the liver of Eriocheir sinensis. Fluorescent microplastic particles (diameter = 0.5 μm) accumulated in the gill, liver and gut tissues of E. sinensis were investigated when crabs were exposed to a concentration of 40000 μg/L for 7 days. A 21 day toxicity test suggested that the rate of weight gain, specific growth rate, and hepatosomatic index of E. sinensis decreased with increasing microplastic concentration (0 μg/L, 40 μg/L, 400 μg/L, 4000 μg/L and 40000 μg/L). The activities of AChE and GPT in crabs exposed to microplastics were lower than those in control group. GOT activity increased significantly after exposure to a low concentration of microplastics and then decreased continuously with increasing microplastic concentrations. The activities of superoxide dismutase (SOD), aspartate transaminase (GOT), glutathione (GSH), and glutathione peroxidase (GPx) increased in specimens exposed to low concentrations of microplastics (40 and 400 μg/L) compared to the control and decreased in organisms exposed to high concentrations (4000 and 40000 μg/L). In contrast, the activities of acetylcholinesterase, catalase (CAT), and alanine aminotransferase were significantly lower in the organisms exposed to microplastics compared to control animals. Upon exposure to increasing microplastic concentrations, the expression of genes encoding the antioxidants SOD, CAT, GPx and glutathione S-transferase in the liver decreased after first increasing. Exposure to microplastics increased the expression of the gene encoding p38 in the MAPK signaling pathway and significantly decreased the expressions of genes encoding ERK, AKT, and MEK. The results of this study demonstrate that microplastics can accumulate in the tissues of E. sinensis and negatively affect growth. In addition, exposure to microplastics causes damage and induces oxidative stress in the hepatopancreas of E. sinensis. The findings provide basic biological data for environmental and human risk assessments of microplastics of high concern.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.015
      Issue No: Vol. 200 (2018)
       
  • Stage-dependent effects of chlorpyrifos on medaka (Oryzias latipes)
           swimming behavior using a miniaturized swim flume
    • Authors: Salvador Sastre; Carlos Fernández Torija; Irene Atiénzar Pertusa; Eulalia María Beltrán; María Victoria Pablos; Miguel González-Doncel
      Pages: 37 - 49
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Salvador Sastre, Carlos Fernández Torija, Irene Atiénzar Pertusa, Eulalia María Beltrán, María Victoria Pablos, Miguel González-Doncel
      By considering chlorpyrifos (CPF), an organophosphorus pesticide with known mechanisms of action that affect neurobehavioral development, we assessed the validity and sensitivity of a miniaturized swim flume by investigating the effects of the insecticide on swimming behavior in medaka (Oryzias latipes) fish growing stages. Medaka in three developmental periods, namely 0, 20 and 40 day-old post-hatch (i.e. time points 0, 20 and 40, respectively), were exposed to CPF (12.5, 25, 50 and 100 μg/L) for 48 h under semi-static conditions. The CPF half-lives during exposures were evaluated and the swimming patterns in a flume section (arena) were presented on two-dimensional gradient maps of forced movement of fish against water current. A comparative numerical analysis of fish residence times between each time point control and the corresponding CPF groups was performed by dividing arenas into 15 proportional areas. The time point 0 control group gradient map showed a noticeably different swim pattern from those of the ≥12.5 μg CPF/L groups, which was statistically supported by the differences for residence times seen in ≥12 corresponding areas. The control group gradient maps for time points 20 and 40 differed from those of the respective ≥12.5 μg CPF/L groups. The comparative analysis of the residence times in the corresponding 15 areas revealed differences in ≥5 areas for time point 20 and in ≥3 areas for time point 40. The integrative analysis of the gradient maps and the numerical statistics revealed stage-specific effects and a concentration-response relationship between CPF and alterations on forced medaka swimming despite the dissipation of CPF from the water column. These results indicate the validity of the miniaturized swim flume toward a more environmentally realistic scenario for the evaluation of neurodevelopmental and behavioral toxicity in small fish models.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.008
      Issue No: Vol. 200 (2018)
       
  • Bifenthrin causes transcriptomic alterations in mTOR and ryanodine
           receptor-dependent signaling and delayed hyperactivity in developing
           zebrafish (Danio rerio)
    • Authors: Daniel F. Frank; Galen W. Miller; Danielle J. Harvey; Susanne M. Brander; Juergen Geist; Richard E. Connon; Pamela J. Lein
      Pages: 50 - 61
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Daniel F. Frank, Galen W. Miller, Danielle J. Harvey, Susanne M. Brander, Juergen Geist, Richard E. Connon, Pamela J. Lein
      Over the last few decades, the pyrethroid insecticide bifenthrin has been increasingly employed for pest control in urban and agricultural areas, putting humans and wildlife at increased risk of exposure. Exposures to nanomolar (nM) concentrations of bifenthrin have recently been reported to alter calcium oscillations in rodent neurons. Neuronal calcium oscillations are influenced by ryanodine receptor (RyR) activity, which modulates calcium-dependent signaling cascades, including the mechanistic target of rapamycin (mTOR) signaling pathway. RyR activity and mTOR signaling play critical roles in regulating neurodevelopmental processes. However, whether environmentally relevant levels of bifenthrin alter RyR or mTOR signaling pathways to influence neurodevelopment has not been addressed. Therefore, our main objectives in this study were to examine the transcriptomic responses of genes involved in RyR and mTOR signaling pathways in zebrafish (Danio rerio) exposed to low (ng/L) concentrations of bifenthrin, and to assess the potential functional consequences by measuring locomotor responses to external stimuli. Wildtype zebrafish were exposed for 1, 3 and 5 days to 1, 10 and 50 ng/L bifenthrin, followed by a 14 d recovery period. Bifenthrin elicited significant concentration-dependent transcriptional responses in the majority of genes examined in both signaling cascades, and at all time points examined during the acute exposure period (1, 3, and 5 days post fertilization; dpf), and at the post recovery assessment time point (19 dpf). Changes in locomotor behavior were not evident during the acute exposure period, but were observed at 19 dpf, with main effects (increased locomotor behavior) detected in fish exposed developmentally to bifenthrin at 1 or 10 ng/L, but not 50 ng/L. These findings illustrate significant influences of developmental exposures to low (ng/L) concentrations of bifenthrin on neurodevelopmental processes in zebrafish.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.003
      Issue No: Vol. 200 (2018)
       
  • Basis of genetic adaptation to heavy metal stress in the acidophilic green
           alga Chlamydomonas acidophila
    • Authors: Fernando Puente-Sánchez; Silvia Díaz; Vanessa Penacho; Angeles Aguilera; Sanna Olsson
      Pages: 62 - 72
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Fernando Puente-Sánchez, Silvia Díaz, Vanessa Penacho, Angeles Aguilera, Sanna Olsson
      To better understand heavy metal tolerance in Chlamydomonas acidophila, an extremophilic green alga, we assembled its transcriptome and measured transcriptomic expression before and after Cd exposure in this and the neutrophilic model microalga Chlamydomonas reinhardtii. Genes possibly related to heavy metal tolerance and detoxification were identified and analyzed as potential key innovations that enable this species to live in an extremely acid habitat with high levels of heavy metals. In addition we provide a data set of single orthologous genes from eight green algal species as a valuable resource for comparative studies including eukaryotic extremophiles. Our results based on differential gene expression, detection of unique genes and analyses of codon usage all indicate that there are important genetic differences in C. acidophila compared to C. reinhardtii. Several efflux family proteins were identified as candidate key genes for adaptation to acid environments. This study suggests for the first time that exposure to cadmium strongly increases transposon expression in green algae, and that oil biosynthesis genes are induced in Chlamydomonas under heavy metal stress. Finally, the comparison of the transcriptomes of several acidophilic and non-acidophilic algae showed that the Chlamydomonas genus is polyphyletic and that acidophilic algae have distinctive aminoacid usage patterns.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.020
      Issue No: Vol. 200 (2018)
       
  • Genome-wide scan reveals signatures of selection related to pollution
           adaptation in non-model estuarine Atlantic killifish (Fundulus
           heteroclitus)
    • Authors: J.S. Osterberg; K.M. Cammen; T.F. Schultz; B.W. Clark; R.T. Di Giulio
      Pages: 73 - 82
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): J.S. Osterberg, K.M. Cammen, T.F. Schultz, B.W. Clark, R.T. Di Giulio
      In many human-altered ecosystems, organisms are increasingly faced with more diverse and complex environmental stressors and pollutant mixtures, to which the adaptations necessary to survive exposure are likely to be numerous and varied. Improving our understanding of the molecular mechanisms that underlie complex polygenic adaptations in natural settings requires significant toxicological, biochemical, physiological, and genomic data rarely available for non-model organisms. Here, we build upon two decades of study of adaptation to anthropogenic pollutants in a population of Atlantic killifish (Fundulus heteroclitus) that inhabits the creosote-contaminated Atlantic Wood Industries Superfund (AW) site on the Elizabeth River, Virginia in the United States. To better understand the genotypes that underlie previously characterized resistance to PCBs and PAHs, we performed Restriction site-Associated DNA sequencing (RADseq) on killifish from AW and two relatively clean reference sites (King’s Creek–KC, and Mains Creek–MC). Across the genome, we analyzed over 83,000 loci and 12,000 single nucleotide polymorphisms (SNPs). Shared across both comparisons of killifish from polluted (AW) and relatively unpolluted (KC and MC) sites, we found eight genomic regions with smoothed F ST values significantly (p < 0.001) elevated above background. Using the recently published F. heteroclitus reference genome, we identified candidate genes in these significant regions involved in the AHR pathway (e.g. AIP, ARNT1c), as well as genes relating to cardiac structure and function. These genes represent both previously characterized and potentially novel molecular adaptations involved with various aspects of resistance to these environmental toxins.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.017
      Issue No: Vol. 200 (2018)
       
  • Effects of environmental stressors on lipid metabolism in aquatic
           invertebrates
    • Authors: Min-Chul Lee; Jun Chul Park; Jae-Seong Lee
      Pages: 83 - 92
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Min-Chul Lee, Jun Chul Park, Jae-Seong Lee
      Lipid metabolism is crucial for the survival and propagation of the species, since lipids are an essential cellular component across animal taxa for maintaining homeostasis in the presence of environmental stressors. This review aims to summarize information on the lipid metabolism under environmental stressors in aquatic invertebrates. Fatty acid synthesis from glucose via de novo lipogenesis (DNL) pathway is mostly well-conserved across animal taxa. The structure of free fatty acid (FFA) from both dietary and DNL pathway could be transformed by elongase and desaturase. In addition, FFA can be stored in lipid droplet as triacylglycerol, upon attachment to glycerol. However, due to the limited information on both gene and lipid composition, in-depth studies on the structural modification of FFA and their storage conformation are required. Despite previously validated evidences on the disturbance of the normal life cycle and lipid homeostasis by the environmental stressors (e.g., obesogens, salinity, temperature, pCO2, and nutrients) in the aquatic invertebrates, the mechanism behind these effects are still poorly understood. To overcome this limitation, omics approaches such as transcriptomic and proteomic analyses have been used, but there are still gaps in our knowledge on aquatic invertebrates as well as the lipidome. This paper provides a deeper understanding of lipid metabolism in aquatic invertebrates.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.016
      Issue No: Vol. 200 (2018)
       
  • Effects of ozonated sewage effluent on reproduction and behavioral
           endpoints in zebrafish (Danio rerio)
    • Authors: Johannes Pohl; Berndt Björlenius; Tomas Brodin; Gunnar Carlsson; Jerker Fick; D.G. Joakim Larsson; Leif Norrgren; Stefan Örn
      Pages: 93 - 101
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Johannes Pohl, Berndt Björlenius, Tomas Brodin, Gunnar Carlsson, Jerker Fick, D.G. Joakim Larsson, Leif Norrgren, Stefan Örn
      Pharmaceutical residues and other micro-contaminants may enter aquatic environments through effluent from sewage treatment plants (STPs) and could cause adverse effects in wild fish. One strategy to alleviate this situation is to improve wastewater treatment by ozonation. To test the effectiveness of full-scale wastewater effluent ozonation at a Swedish municipal STP, the added removal efficiency was measured for 105 pharmaceuticals. In addition, gene expression, reproductive and behavioral endpoints were analyzed in zebrafish (Danio rerio) exposed on-site over 21 days to ozonated or non-ozonated effluents as well as to tap water. Ozone treatment (7 g O3/m3) removed pharmaceuticals by an average efficiency of 77% in addition to the conventional treatment, leaving 11 screened pharmaceuticals above detection limits. Differences in biological responses of the exposure treatments were recorded in gene expression, reproduction and behavior. Hepatic vitellogenin gene expression was higher in male zebrafish exposed to the ozonated effluent compared to the non-ozonated effluent and tap water treatments. The reproductive success was higher in fish exposed to ozonated effluent compared to non-ozonated effluent and to tap water. The behavioral measurements showed that fish exposed to the ozonated STP effluent were less active in swimming the first minute after placed in a novel vessel. Ozonation is a capable method for removing pharmaceuticals in effluents. However, its implementation should be thoroughly evaluated for any potential biological impact. Future research is needed for uncovering the factors which produced the in vivo responses in fish.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.014
      Issue No: Vol. 200 (2018)
       
  • Silver nanoparticles impair zebrafish skeletal and cardiac
           myofibrillogenesis and sarcomere formation
    • Authors: Qin-Han Xu; PengPeng Guan; Ting Zhang; Chang Lu; GuoLiang Li; Jing-Xia Liu
      Pages: 102 - 113
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Qin-Han Xu, PengPeng Guan, Ting Zhang, Chang Lu, GuoLiang Li, Jing-Xia Liu
      Metal nanoparticles from industries contaminate the environment and affect the normal development of fish even human health. However, little is known about their biological effects on fish embryogenesis and the potential mechanisms. In this study, zebrafish embryos exposed to/injected with silver nanopaticles (AgNPs) exhibited shorter body, reduced heartbeats, and dysfunctional movements. Less, loose, and unassembled myofibrils were observed in AgNPs-treated embryos, and genes in myofibrillogenesis and sarcomere formation were found to be down-regulated in treated embryos. Down-regulated calcium (Ca2+) signaling and loci-specific DNA methylation in specific muscle genes, such as bves, shroom1, and arpc1a, occurred in AgNPs-treated embryos, which might result in the down-regulated expression of myofibrillogenesis genes and muscle dysfunctions in the treated embryos. Our results for the first time reveal that through down-regulating Ca2+ signaling and myogenic loci-specific DNA methylation in zebrafish embryos, AgNPs might induce defects of myofibril assembly and sarcomere formation via their particles mostly, which may subsequently cause heartbeat reduction and behavior dysfunctions.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.018
      Issue No: Vol. 200 (2018)
       
  • Tritiated water exposure disrupts myofibril structure and induces
           mis-regulation of eye opacity and DNA repair genes in zebrafish early life
           stages
    • Authors: Caroline Arcanjo; Olivier Armant; Magali Floriani; Isabelle Cavalie; Virginie Camilleri; Olivier Simon; Daniel Orjollet; Christelle Adam-Guillermin; Béatrice Gagnaire
      Pages: 114 - 126
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Caroline Arcanjo, Olivier Armant, Magali Floriani, Isabelle Cavalie, Virginie Camilleri, Olivier Simon, Daniel Orjollet, Christelle Adam-Guillermin, Béatrice Gagnaire
      Tritium (3H) is a radioactive isotope of hydrogen. In the environment, the most common form of tritium is tritiated water (HTO). The present study aimed to identify early biomarkers of HTO contamination through the use of an aquatic model, the zebrafish (Danio rerio). We used the zebrafish embryo-larvae model to investigate the modes of action of HTO exposure at dose rates of 0.4 and 4 mGy/h, dose rates expected to induce deleterious effects on fish. Zebrafish were exposed to HTO from 3 hpf (hours post fertilization) to 96 hpf. The transcriptomic effects were investigated 24 h and 96 h after the beginning of the contamination, using mRNAseq. Results suggested an impact of HTO contamination, regardless of the dose rate, on genes involved in muscle contraction (tnnt2d, tnni2a.4, slc6a1a or atp2a1l) and eye opacity (crygm2d9, crygmxl1, mipb or lim2.3) after 24 h of contamination. Interestingly, an opposite differential expression was highlighted in genes playing a role in muscle contraction and eye opacity in 24 hpf embryos when comparing dose rates, suggesting an onset of DNA protective mechanisms. The expression of h2afx and ddb2 involved in DNA repair was enhanced in response to HTO exposure. The entrainment of circadian clock and the response to H2O2 signalling pathways were enriched at 96 hpf at 0.4 mGy/h and in both stages after 4 mGy/h. Genes involved in ROS scavenging were differentially expressed only after 24 h of exposure for the lowest dose rate, suggesting the onset of early protective mechanisms against oxidative stress. Effects highlighted on muscle at the molecular scale were confirmed at a higher biological scale, as electron microscopy observations revealed sarcomere impairments in 96 hpf larvae for both dose rates. Together with other studies, the present work provides useful data to better understand modes of action of tritium on zebrafish embryos-larvae.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.012
      Issue No: Vol. 200 (2018)
       
  • Adverse effects and immune dysfunction in response to oral administration
           of weathered Iranian heavy crude oil in the rockfish Sebastes schlegeli
    • Authors: Eun-Hee Lee; Moonkoo Kim; Young-Sun Moon; Un Hyuk Yim; Sung Yong Ha; Chang-Bum Jeong; Jae-Seong Lee; Jee-Hyun Jung
      Pages: 127 - 135
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Eun-Hee Lee, Moonkoo Kim, Young-Sun Moon, Un Hyuk Yim, Sung Yong Ha, Chang-Bum Jeong, Jae-Seong Lee, Jee-Hyun Jung
      To demonstrate the effects of weathered crude oil residue on the immune systems of resident fish, we measured the changes in toxic chemical concentrations, apoptosis, phagocytosis, metabolism, immune-related gene expression, and cell cycle arrest in livers or kidneys for up to 96 h after the weathered Iranian heavy crude oil (WIHCO) exposure by oral gavage in juvenile rockfish Sebastes schlegeli. Parent polyaromatic hydrocarbons (PAHs) in livers increased up to 5590 ng/g after 6 h exposure and then declined rapidly within 24 h. Hepato-detoxification and immune-related gene expression were also significantly increased (P < 0.05) after 6 h exposure and then declined rapidly within 24 h. However, biliary PAH metabolites and EROD activity remained elevated throughout the test period. Flow cytometry analysis also indicated sustained apoptosis and cell cycle arrests with reduced phagocytic activity for 96 h. Taken together, these results demonstrate rapid declination of the parent PAHs, whereas PAH metabolites remained much longer in tissues with prolonged suppression of immunity in molecular and cellular level, suggesting that weathered crude oil residue is likely linked to the high incidence of immune dysfunction in residential rockfish in oil spill area.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.010
      Issue No: Vol. 200 (2018)
       
  • Interactions of oxidized multiwalled carbon nanotube with cadmium on
           zebrafish cell line: The influence of two co-exposure protocols on in
           vitro toxicity tests
    • Authors: Mariana Morozesk; Lidiane S. Franqui; Adrislaine S. Mansano; Diego Stéfani T. Martinez; Marisa N. Fernandes
      Pages: 136 - 147
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Mariana Morozesk, Lidiane S. Franqui, Adrislaine S. Mansano, Diego Stéfani T. Martinez, Marisa N. Fernandes
      The widespread production and application of carbon nanotubes (CNT) have raising concerns about their release into the environment and, the joint toxicity of CNT with pre-existing contaminants needs to be assessed. This is the first study that investigated the co-exposure of oxidized multiwalled carbon nanotubes (ox-MWCNT) and cadmium (Cd) using a zebrafish liver cell line (ZFL). Two in vitro co-exposure protocols differing by the order of ox-MWCNT interaction with Cd and fetal bovine serum (FBS) proteins were evaluated. Ox-MWCNT was physical and chemical characterized and its adsorption capacity and colloidal stability in cell culture medium was determined in both protocols. Cytotoxicity was investigated by MTT, neutral red, trypan blue, lactate dehydrogenase assays and the necrosis and apoptosis events were determined using flow cytometer. The Cd presence in medium did not interfere in the protein corona composition of MWCNT but the order of interaction of FBS and Cd interfered in its colloidal stability and metal adsorption rate. The ox-MWCNT increased Cd toxicity at low concentration probably by a “Trojan horse” and/or synergistic effect, and induced apoptosis and necrosis in ZFL cells. Although it was not observed differences of toxicity between protocols, the interaction of ox-MWCNT first with Cd led to its precipitation in cell culture medium and, as a consequence, to a possible false viability result by neutral red assay. Taken together, it was evident that the order of compounds interactions disturbs the colloidal stability and affects the in vitro toxicological assays. Considering that Protocol A showed more ox-MWCNT stability after interaction with Cd, this protocol is recommended to be adopted in future studies.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.002
      Issue No: Vol. 200 (2018)
       
  • Combined effects of metal mixtures and predator stress on the freshwater
           isopod Asellus aquaticus
    • Authors: M. Van Ginneken; R. Blust; L. Bervoets
      Pages: 148 - 157
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): M. Van Ginneken, R. Blust, L. Bervoets
      Biotic stressors have been demonstrated to change the toxicity of pollutants. While the combined effects of predator cues and pesticides are well documented, the interaction of predator stress with metals is a topic that has remained largely unexplored. In this laboratory experiment, the freshwater isopod Asellus aquaticus is exposed to predator cues and metal mixtures of Cd, Cu and Pb. We examined the effects on growth, respiration and, as behavioral parameters, feeding rate and activity. These were linked to the free ion activities (FIAs) in the water and the metal body concentrations. The findings reveal that Cu accumulation significantly influenced the growth rate, the feeding rate and the activity of isopods exposed to predator stress. Furthermore, we found a concentration-dependent interaction of the Cd + Pb mixtures on the feeding rate and a lower feeding rate for Cd and Pb predator exposed asellids. As several interactions were found between metals and predator stress, it demonstrates the importance of investigating how organisms and whole ecosystems respond to multiple stressors. A better understanding of these interactions will undoubtedly improve risk assessment and management.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.021
      Issue No: Vol. 200 (2018)
       
  • An in vivo analysis of Cr6+ induced biochemical, genotoxicological and
           transcriptional profiling of genes related to oxidative stress, DNA damage
           and apoptosis in liver of fish, Channa punctatus (Bloch, 1793)
    • Authors: Yashika Awasthi; Arun Ratn; Rajesh Prasad; Manoj Kumar; Sunil P. Trivedi
      Pages: 158 - 167
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Yashika Awasthi, Arun Ratn, Rajesh Prasad, Manoj Kumar, Sunil P. Trivedi
      Present study was designed to assess the hexavalent chromium (Cr6+) mediated oxidative stress that induces DNA damage and apoptosis in adult fish, Channa punctatus (35 ± 3.0 g; 14.5 ± 1.0 cm; Actinopterygii). Fishes were maintained in three groups for 15, 30 and 45 d of exposure periods. They were treated with 5% (Group T1) and 10% (Group T2) of 96 h-LC50 of chromium trioxide (Cr6+). Controls were run for the similar duration. A significant (p < 0.05) increment in the activities of antioxidant enzymes, SOD and CAT in liver tissues of the exposed fish evinces the persistence of oxidative stress. A significant (p < 0.05) increase in induction of micronuclei (MN) coupled with transcriptional responses of target genes related to antioxidant enzymes, DNA damage and apoptosis (sod, cat, gsr, nox-1, p53, bax, bcl-2, apaf-1 and casp3a) establishes the impact of oxidative stress due to in vivo, Cr6+ accumulation in liver as compared to control (0 mg/L), in a dose and exposure-dependent manner. Initially, the increased level of reactive oxygen species (ROS) in liver coincided with that of enhanced mRNA expression of antioxidant enzymes, sod, cat, gsr and nox-1 but, later, the overproduction of ROS, after 45 d of exposure of Cr6+, resulted in a significant (p < 0.05) up-regulation of p53. Our findings also unveil that the up-regulation of bax, apaf-1 and casp3a and down-regulation of bcl-2 are associated with Cr6+-induced oxidative stress mediated-apoptosis in liver of test fish. Aforesaid molecular markers can, thus, be efficiently utilized for bio-monitoring of aquatic regimes and conservation of fish biodiversity.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.001
      Issue No: Vol. 200 (2018)
       
  • Mitochondria-rich cells adjustments and ionic balance in the Neotropical
           fish Prochilodus lineatus exposed to titanium dioxide nanoparticles
    • Authors: Talita L.L. Carmo; Vinícius C. Azevedo; Priscila R. Siqueira; Tiago D. Galvão; Fabrício A. Santos; Cláudia B.R. Martinez; Carlos R. Appoloni; Marisa N. Fernandes
      Pages: 168 - 177
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Talita L.L. Carmo, Vinícius C. Azevedo, Priscila R. Siqueira, Tiago D. Galvão, Fabrício A. Santos, Cláudia B.R. Martinez, Carlos R. Appoloni, Marisa N. Fernandes
      Manufactured titanium dioxide nanoparticles (TiO2-NP) have been intensely applied in numerous industrial products and may be a risk for aquatic systems as they are not completely removed from domestic and industrial wastes after water treatment. This study evaluated the osmo- and ionic balance, Na+/K+-ATPase, H+-ATPase and carbonic anhydrase activities and the mitochondria-rich cells (MRC) in the gills and kidney of the Neotropical fish Prochilodus lineatus after 2 (acute) and 14 (subchronic) days of exposure to nominal 0, 1, 5, 10 and 50 mg L−1 TiO2-NP. The nominal concentrations corresponded to 0.0, 0.6, 1.6, 2.7 and 18.1 mg L-1 suspended TiO2-NP, respectively, in the water column one hour after NP introduction and were maintained for at least 24 h. Acute exposure to TiO2-NP decreased plasma osmolality and Ca2+ levels. Na+/K+-ATPase, H+-ATPase and carbonic anhydrase activities were inhibited in the gills, but not in the kidney. Total MRC density did not change in gills and kidneys. At gill surface, total MRC density decreased in fish exposed to 50 mg L−1 TiO2-NP and the total MRC fractional surface area unchanged although, there were some changes in the fractional area of MRC with apical microvilli (MRCm) and MRC with apical sponge-like structure (MRCs). MRCm was more abundant than MRCs. After subchronic exposure, there was no change in plasma osmolality, ionic balance and enzyme activities. Total gill MRC density increased in the filament epithelium and renal tubules. In the gills, MRC contacting water exhibited some adjustments. Total MRC and fractional surface area unchanged, but there was an increase of MRCs contacting water at gill surface after exposure to10 and 50 mg L−1 TiO2-NP. MRC proliferation in filament epithelium and in renal tubules as well as the increasing MRCs at gill surface may have contributed to avoid change in plasma osmolality, ionic balance and enzyme activities and suggested a cellular physiological and morphological response to restore and maintain osmotic and ionic homeostasis after subchronic exposure.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.006
      Issue No: Vol. 200 (2018)
       
  • Exposure to tris(1,3-dichloro-2-propyl) phosphate for Two generations
           decreases fecundity of zebrafish at environmentally relevant
           concentrations
    • Authors: Yongkang Zhang; Meng Li; Shuying Li; Qiangwei Wang; Guonian Zhu; Guanyong Su; Robert J. Letcher; Chunsheng Liu
      Pages: 178 - 187
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Yongkang Zhang, Meng Li, Shuying Li, Qiangwei Wang, Guonian Zhu, Guanyong Su, Robert J. Letcher, Chunsheng Liu
      Previous studies reported that exposure to environmentally relevant concentrations of TDCIPP significantly decreased the number of cumulative eggs in zebrafish, but effects on the quantity of eggs and sperms remained unknown. Therefore, in this study, effects of TDCIPP on yolk diameter, surface morphology of eggs, sperm density and total motility were evaluated. First generation (F0) zebrafish larvae (Danio rerio) were exposed to 0, 50, 500 or 5000 ng/L tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) from 14 days post fertilization (dpf) to 120 dpf. The F0 generation of zebrafish were paired and F1 generation of embryos were collected and continuously exposed to the same concentrations of TDCIPP until 150 dpf. TDCIPP bioconcentration in the whole body as well as effects on survival and fecundity were evaluated in F1 generation. Exposure to TDCIPP resulted in an accumulation of the chemical and decreased survival of F1 generation of zebrafish. TDCIPP decreased cumulative production and changed surface morphology of eggs in females. In males, TDCIPP decreased total motility of sperm but did not affect sperm density. These effects on quality of egg and sperm might be responsible for the decreased hatching rates observed in cross mating experiments. Furthermore, TDCIPP exposure resulted in down-regulated gene expression related to gonadal development and maturation of germ cells in females or/and males, and the down-regulation was correlated to decreased fecundity. Taken together, the results suggested that exposure to TDCIPP could decrease the quantity of eggs and sperms by down-regulating the expression of genes related to gonadal development and maturation of germ cells in zebrafish.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.010
      Issue No: Vol. 200 (2018)
       
  • Chlorophyll a fluorescence and transcriptome reveal the toxicological
           effects of bisphenol A on an invasive cyanobacterium, Cylindrospermopsis
           raciborskii
    • Authors: Rong Xiang; Junqiong Shi; Hongbo Zhang; Congcong Dong; Li Liu; JunKe Fu; Xinyu He; Yanjun Yan; Zhongxing Wu
      Pages: 188 - 196
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Rong Xiang, Junqiong Shi, Hongbo Zhang, Congcong Dong, Li Liu, JunKe Fu, Xinyu He, Yanjun Yan, Zhongxing Wu
      Bisphenol A has attracted worldwide attention due to its harmful effects on humans, animals and plants. In this study, the toxicological effects of BPA on Cylindrospermopsis raciborskii were assessed based on chlorophyll a fluorescence and transcriptome analyses. The results showed that the growth of C. raciborskii was significantly inhibited when BPA exceeded 0.1 mg L−1. A marked rise of phase J was observed at a concentration greater than 0.1 mg L−1, while a K phase appeared at 20 mg L−1. The chlorophyll a fluorescence parameters of RC/CS0, F0, φP0, φE0, and ψ0, underwent a significant decline under all treatments of BPA, whereas a significant increase in both VJ and M0 occurred under all concentrations of BPA. Additionally, ABS/RC and DIo/RC markedly increased at 10 mg L−1 and 20 mg L−1. The transcriptome analysis revealed that the genes of photosynthesis, including psbA, psbB, psbC, psbD, apcA, apcB, cpcA, and cpcB, as well as those of chlorophyll and carotenoid biosynthesis, namely hemN, acsF, chlL, chlN, chlP, crtB, pds, were all down-regulated. Moreover, BPA also inhibited the oxidative phosphorylation, glycolysis/gluconeogenesis, citrate cycle (TCA cycle), and fatty acid metabolism in C. raciborskii. Taken together, these results suggest BPA can negatively affect the expression of multiple genes and the vital energy metabolism process to arrest the growth and photosynthesis of C. raciborskii.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.005
      Issue No: Vol. 200 (2018)
       
  • Effects of microcystin-LR on the tissue growth and physiological responses
           of the aquatic plant Iris pseudacorus L.
    • Authors: Naiyu Wang; Can Wang
      Pages: 197 - 205
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Naiyu Wang, Can Wang
      The release of cyanobacterial toxins during algal bloom has adverse effects on aquatic plants and animals. This study aimed to understand the toxic effects and mechanism of microcystin-LR (MC-LR) on the seedling growth and physiological responses of Iris pseudacorus L. (calamus). After a one-month exposure experiment, the growth and development of the calamus leaves were significantly inhibited, and this inhibitory effect was verified to be concentration dependent. Furthermore, the cell membrane system was damaged, and the photosynthesis was also adversely affected by MC-LR. The relative conductivity of the leaves increased from 10.96% to 97.51%, and the total chlorophyll content decreased from 0.89 mg/g to 0.09 mg/g. Notably, the behavior of the roots in the presence of MC-LR was different from that of the leaves. The seedlings needed to absorb more nutrients to maintain the normal growth at low-toxin concentrations, but the high concentration of (over 250 μg/L) MC-LR exceeded the tolerance of plants and inhibited the growth of roots. In addition, MC-LR led to an excessive accumulation of H2O2, and the seedlings enhanced the activities of catalase, peroxidase, and superoxide dismutase to resist oxidative stress. The presence of MC-LR also affected the capacity of the plants to absorb nitrogen and phosphorus. The removal efficiency of NO3 −-N, the main source of nitrogen, was 63.53% in the presence of 100 μg/L MC-LR. As a result, the pH increased, and the growth of plants was indirectly inhibited. Therefore, the presence of MC-LR could affect the purification efficiency of calamus in eutrophic water. This study provides theoretical support for the selection of plants in the eutrophic water.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.04.019
      Issue No: Vol. 200 (2018)
       
  • Tributyltin impaired reproductive success in female zebrafish through
           disrupting oogenesis, reproductive behaviors and serotonin synthesis
    • Authors: Wei-Yang Xiao; Ying-Wen Li; Qi-Liang Chen; Zhi-Hao Liu
      Pages: 206 - 216
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Wei-Yang Xiao, Ying-Wen Li, Qi-Liang Chen, Zhi-Hao Liu
      Tributyltin (TBT), an organotin acting as aromatase (Cyp19a1) inhibitor, has been found to disrupt gametogenesis and reproductive behaviors in several fish species. However, few studies addressing the mechanisms underlying the impaired gametogenesis and reproduction have been reported. In this study, female adults of zebrafish (Danio rerio) were continuously exposed to two nominal concentrations of TBT (100 and 500 ng/L, actual concentrations: 90.8 ± 1.3 ng/L and 470.3 ± 2.7 ng/L, respectively) for 28 days. After exposures, TBT decreased the total egg number, reduced the hatchability and elevated the mortality of the larvae. Decreased gonadosomatic index (GSI) and altered percentages of follicles in different developmental stages (increased early-stage follicles and reduced mid/late-stage follicles) were also observed in the ovary of TBT-treated fish. TBT also lowered the plasma level of 17β-estradiol and suppressed the expressions of cyp19a1a in the ovary. In treated fish, up-regulated expressions of aldhla2, sycp3 and dmc1 were present in the ovary, indicating an enhanced level of meiosis. The mRNA level of vtg1 was dramatically suppressed in the liver of TBT-treated fish, suggesting an insufficient synthesis of Vtg protein, consistent with the decreased percentage of mid/late-stage follicles in the ovaries. Moreover, TBT significantly suppressed the reproductive behaviors of the female fish (duration of both sexes simultaneously in spawning area, the frequency of meeting and the visit in spawning area) and down-regulated the mRNA levels of genes involved in the regulation of reproductive behaviors (cyp19a1b, gnrh-3 and kiss 2) in the brain. In addition, TBT significantly suppressed the expressions of serotonin-related genes, such as tph2 (encoding serotonin synthase), pet1 (marker of serotonin neuron) and kiss 1 (the modulator of serotonin synthesis), suggesting that TBT might disrupt the non-reproductive behaviors of zebrafish. The present study demonstrated that TBT may impair the reproductive success of zebrafish females probably through disrupting oogenesis, disturbing reproductive behaviors and altering serotonin synthesis. The present study greatly extends our understanding on the reproductive toxicity of TBT on fish.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.009
      Issue No: Vol. 200 (2018)
       
  • Negative impacts of elevated nitrate on physiological performance are not
           exacerbated by low pH
    • Authors: Daniel F. Gomez Isaza; Rebecca L. Cramp; Craig E. Franklin
      Pages: 217 - 225
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Daniel F. Gomez Isaza, Rebecca L. Cramp, Craig E. Franklin
      Multiple environmental stressors, including nutrient effluents (i.e. nitrates [ N O 3 − ]) and altered pH regimes, influence the persistence of freshwater species in anthropogenically disturbed habitats. Independently, nitrate and low pH affect energy allocation by increasing maintenance costs and disrupting oxygen uptake, which ultimately results in impacts upon whole animal performance. However, the interaction between these two stressors has not been characterised. To address this, the effects of nitrate and pH and their interaction on aerobic scope and physiological performance were investigated in the blueclaw crayfish, Cherax destructor. Crayfish were exposed to a 2 × 3 factorial combination, with two pH levels (pH 5.0 and 7.0) and three nitrate concentrations (0, 50 and 100 mg L−1 N O 3 − ). Crayfish were exposed to experimental conditions for 65 days and growth and survival were monitored. Aerobic scope (i.e. maximal – standard oxygen uptake) was measured at six time points (1, 3, 5, 7, 14, and 21 days) during exposure to experimental treatments. Crayfish performance was assessed after 28 days, by measuring chelae strength and whole animal activity capacity via the righting response. Survival was reduced in crayfish exposed to pH 5.0, but there was no exacerbation of this effect by exposure to high nitrate levels. Aerobic scope was compromised by the interaction between low pH and nitrate and resulted in prolonged elevations of standard oxygen uptake rates. Exposure to nitrate alone affected aerobic scope, causing a 59% reduction in maximum oxygen uptake. Reduced aerobic capacity translated to reduced chelae strength and righting capacity. Together, these data show that low pH and elevated nitrate levels reduce aerobic scope and translate to poorer performance in C. destructor, which may have the potential to affect organismal fitness in disturbed habitats.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.004
      Issue No: Vol. 200 (2018)
       
  • Environmentally relevant concentrations of tramadol and citalopram alter
           behaviour of an aquatic invertebrate
    • Authors: M. Buřič; K. Grabicová; J. Kubec; A. Kouba; I. Kuklina; P. Kozák; R. Grabic; T Randák
      Pages: 226 - 232
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): M. Buřič, K. Grabicová, J. Kubec, A. Kouba, I. Kuklina, P. Kozák, R. Grabic, T Randák
      Environmental pollution by pharmaceutically active compounds, used in quantities similar to those of pesticides and other organic micropollutants, is increasingly recognized as a major threat to the aquatic environment. These compounds are only partly removed from wastewaters and, despite their low concentrations, directly and indirectly affect behaviour of freshwater organisms in natural habitats. The aim of this study was to behaviourally assess the effects of an opioid painkiller (tramadol) and antidepressant drug (citalopram) on behaviour patterns of a clonal model species, marbled crayfish. Animals exposed to environmentally relevant concentrations of both tested compounds (∼1 μg l−1) exhibited significantly lower velocity and shorter distance moved than controls. Crayfish exposed to tramadol spent more time in shelters. Results were obtained by a simple and rapid method recommended as suitable for assessment of behaviour in aquatic organisms exposed to single pollutants and combinations.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.008
      Issue No: Vol. 200 (2018)
       
  • Dynamics of paralytic shellfish toxins and their metabolites during
           timecourse exposure of scallops Chlamys farreri and mussels Mytilus
           galloprovincialis to Alexandrium pacificum
    • Authors: Jiangbing Qiu; Fanping Meng; Ling Ding; Yijia Che; Pearse McCarron; Daniel G. Beach; Aifeng Li
      Pages: 233 - 240
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Jiangbing Qiu, Fanping Meng, Ling Ding, Yijia Che, Pearse McCarron, Daniel G. Beach, Aifeng Li
      New C-11 hydroxyl metabolites of paralytic shellfish toxins (PSTs) have been reported in shellfish. To gain further information on these metabolites, as well as the potential for formation of phase-II metabolites and acyl esters of PSTs, bivalves were fed with the PSTs-producing dinoflagellate Alexandrium pacificum (strain ATHK). Through independent experiments, scallops (Chlamys farreri) were fed for 9 days and mussels (Mytilus galloprovincialis) for 5 days plus an additional 5 days of depuration, with representative samples taken throughout. Several common PSTs (C1-4, GTX1-6 and NEO) and metabolites including M1, M3, M5, M7, M9, M2 and M8 were detected in the hepatopancreas of scallops during toxin accumulation and in the hepatopancreas of mussels during both toxin accumulation and elimination periods. The relative molar ratio of metabolites to precursor molecules was used to estimate relative metabolic conversion rates. Conversion rates of C1/2 and GTX2/3 were higher than those of C3/4 and GTX1/4, in scallops and mussels. The first metabolites observed in both bivalve species investigated were M1/3, which are formed from C1/2. However, the conversion of GTX2/3 to M2 was more complete than other biotransformation reactions in both mussels and scallops. In general, metabolic conversion of PSTs was observed after a shorter time and to a greater extent in mussels than in scallops in the exposure period. No acyl esters or conjugation products of PSTs with glucuronic acid, glutathione, cysteine and taurine were detected by liquid chromatography with high resolution tandem mass spectrometry in the samples investigated. Additionally, only GTX1/4 and GTX2/3 were detected in the kidney of scallops, which demonstrates that PSTs are mainly metabolized through the hepatic metabolism pathway in bivalves. This work improves the understanding of PST metabolism during toxin accumulation and depuration in commercially harvested shellfish.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.003
      Issue No: Vol. 200 (2018)
       
  • Neurotoxic impact of acute TiO2 nanoparticle exposure on a benthic marine
           bivalve mollusk, Tegillarca granosa
    • Authors: Xiaofan Guan; Wei Shi; Shanjie Zha; Jiahuan Rong; Wenhao Su; Guangxu Liu
      Pages: 241 - 246
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Xiaofan Guan, Wei Shi, Shanjie Zha, Jiahuan Rong, Wenhao Su, Guangxu Liu
      The release of nanoparticles (NPs) into the ocean inevitably poses a threat to marine organisms. However, to date, the neurotoxic effects of NPs remains poorly understood in marine bivalve species. Therefore, in order to gain a better understanding of the physiological effects of NPs, the impact of acute (96 h) TiO2 NP exposure on the in vivo concentrations of three major neurotransmitters, the activity of AChE, and the expression of neurotransmitter-related genes was investigated in the blood clam, Tegillarca granosa. The obtained results showed that the in vivo concentrations of the three tested neurotransmitters (DA, GABA, and ACh) were significantly increased when exposed to relatively high doses of TiO2 NPs (1 mg/L for DA and 10 mg/L for ACh and GABA). Additionally, clams exposed to seawater contaminated with TiO2 NP had significantly lower AChE activity. In addition, the expression of genes encoding modulatory enzymes (AChE, GABAT, and MAO) and receptors (mAChR3, GABAD, and DRD3) for the neurotransmitters tested were all significantly down-regulated after TiO2 NP exposure. Therefore, this study has demonstrated the evident neurotoxic impact of TiO2 NPs in T. granosa, which may have significant consequences for a number of the organism’s physiological processes.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.011
      Issue No: Vol. 200 (2018)
       
  • Enhancement of coral calcification via the interplay of nickel and urease
    • Authors: T. Biscéré; C. Ferrier-Pagès; R. Grover; A. Gilbert; C. Rottier; A. Wright; C. Payri; F. Houlbrèque
      Pages: 247 - 256
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): T. Biscéré, C. Ferrier-Pagès, R. Grover, A. Gilbert, C. Rottier, A. Wright, C. Payri, F. Houlbrèque
      Corals are the main reef builders through the formation of calcium carbonate skeletons. In recent decades, coral calcification has however been impacted by many global (climate change) and local stressors (such as destructive fishing practices and changes in water quality). In this particular context, it is crucial to identify and characterize the various factors that promote coral calcification. We thus performed the first investigation of the effect of nickel and urea enrichment on the calcification rates of three coral species. These two factors may indeed interact with calcification through the activity of urease, which catalyzes the hydrolysis of urea to produce inorganic carbon and ammonia that are involved in the calcification process. Experiments were performed with the asymbiotic coral Dendrophyllia arbuscula and, to further assess if urea and/or nickel has an indirect link with calcification through photosynthesis, results were compared with those obtained with two symbiotic corals, Acropora muricata and Pocillopora damicornis, for which we also measured photosynthetic rates. Ambient and enriched nickel (0.12 and 3.50 μg L−1) combined with ambient and enriched urea concentrations (0.26 and 5.52 μmol L−1) were tested during 4 weeks in aquaria. We demonstrate in the study that a nickel enrichment alone or combined with a urea enrichment strongly stimulated urea uptake rates of the three tested species. In addition, this enhancement of urea uptake and hydrolysis significantly increased the long-term calcification rates (i.e. growth) of the three coral species investigated, inducing a 1.49-fold to 1.64-fold increase, respectively for D. arbuscula and P. damicornis. Since calcification was greatly enhanced by nickel in the asymbiotic coral species – i.e. in absence of photosynthesis – we concluded that the effect of increased urease activity on calcification was mainly direct. According to our results, it can be assumed that corals in some fringing reefs, benefiting from seawater enriched in nickel may have advantages and might be able to use urea more effectively as a carbon and nitrogen source. It can also be suggested that urea, for which hotspots are regularly measured in reef waters may alleviate the negative consequences of thermal stress on corals.

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.013
      Issue No: Vol. 200 (2018)
       
  • Experimental evidence of dietary ciguatoxin accumulation in an herbivorous
           coral reef fish
    • Authors: Rachel J. Clausing; Barbara Losen; Francois R. Oberhaensli; H. Taiana Darius; Manoella Sibat; Philipp Hess; Peter W. Swarzenski; Mireille Chinain; Marie-Yasmine Dechraoui Bottein
      Pages: 257 - 265
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): Rachel J. Clausing, Barbara Losen, Francois R. Oberhaensli, H. Taiana Darius, Manoella Sibat, Philipp Hess, Peter W. Swarzenski, Mireille Chinain, Marie-Yasmine Dechraoui Bottein
      Ciguatoxins (CTXs) are potent algal toxins that cause widespread ciguatera poisoning and are found ubiquitously in coral reef food webs. Here we developed an environmentally-relevant, experimental model of CTX trophic transfer involving dietary exposure of herbivorous fish to the CTX-producing microalgae Gambierdiscus polynesiensis. Juvenile Naso brevirostris were fed a gel-food embedded with microalgae for 16 weeks (89 cells g−1 fish daily, 0.4 μg CTX3C equiv kg−1 fish). CTXs in muscle tissue were detectable after 2 weeks at levels above the threshold for human intoxication (1.2 ± 0.2 μg CTX3C equiv kg−1). Although tissue CTX concentrations stabilized after 8 weeks (∼3 ± 0.5 μg CTX3C equiv kg−1), muscle toxin burden (total μg CTX in muscle tissue) continued to increase linearly through the end of the experiment (16 weeks). Toxin accumulation was therefore continuous, yet masked by somatic growth dilution. The observed CTX concentrations, accumulation rates, and general absence of behavioural signs of intoxication are consistent with field observations and indicate that this method of dietary exposure may be used to develop predictive models of tissue-specific CTX uptake, metabolism and depuration. Results also imply that slow-growing fish may accumulate higher CTX flesh concentrations than fast-growing fish, which has important implications for global seafood safety.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.007
      Issue No: Vol. 200 (2018)
       
  • A multibiomarker approach highlights effects induced by the human
           pharmaceutical gemfibrozil to gilthead seabream Sparus aurata
    • Authors: A. Barreto; L.G. Luis; P. Paíga; L.H.M.L.M. Santos; C. Delerue-Matos; A.M.V.M. Soares; K. Hylland; S. Loureiro; M. Oliveira
      Pages: 266 - 274
      Abstract: Publication date: July 2018
      Source:Aquatic Toxicology, Volume 200
      Author(s): A. Barreto, L.G. Luis, P. Paíga, L.H.M.L.M. Santos, C. Delerue-Matos, A.M.V.M. Soares, K. Hylland, S. Loureiro, M. Oliveira
      Lipid regulators are among the most prescribed human pharmaceuticals worldwide. Gemfibrozil, which belongs to this class of pharmaceuticals, is one of the most frequently encountered in the aquatic environment. However, there is limited information concerning the mechanisms involved in gemfibrozil effects to aquatic organisms, particularly to marine organisms. Based on this knowledge gap, the current study aimed to assess biochemical and behavioral effects following a sublethal exposure to gemfibrozil (1.5, 15, 150, 1500 and 15,000 μg L−1) in the estuarine/marine fish Sparus aurata. After the exposure to 1.5 μg L−1 of gemfibrozil, fish had reduced ability to swim against a water flow and increased lipid peroxidation in the liver. At concentrations between 15–15,000 μg L−1, the activities of some enzymes involved in antioxidant defense were induced, appearing to be sufficient to prevent oxidative damage. Depending on the organ, different responses to gemfibrozil were displayed, with enzymes like catalase being more stimulated in gills, whereas glutathione peroxidase was more activated in liver. Although there were no obvious concentration-response relationships, the integrated biomarker response version 2 (IBRv2) analysis revealed that the highest concentrations of gemfibrozil (between 150–15,000 μg L−1) caused more alterations. All the tested concentrations of gemfibrozil induced effects in S. aurata, in terms of behavior and/or oxidative stress responses. Oxidative damage was found at a concentration that is considered environmentally relevant, suggesting a potential of this pharmaceutical to impact fish populations.
      Graphical abstract image

      PubDate: 2018-05-28T21:24:24Z
      DOI: 10.1016/j.aquatox.2018.05.012
      Issue No: Vol. 200 (2018)
       
  • High-throughput assessment of oxidative respiration in fish embryos:
           Advancing adverse outcome pathways for mitochondrial dysfunction
    • Authors: Christopher L. Souders; Xuefang Liang; Xiaohong Wang; Naomi Ector; Yuan H. Zhao; Christopher J. Martyniuk
      Pages: 162 - 173
      Abstract: Publication date: June 2018
      Source:Aquatic Toxicology, Volume 199
      Author(s): Christopher L. Souders, Xuefang Liang, Xiaohong Wang, Naomi Ector, Yuan H. Zhao, Christopher J. Martyniuk
      Mitochondrial dysfunction is a prevalent molecular event that can result in multiple adverse outcomes. Recently, a novel high throughput method to assess metabolic capacity in fish embryos following exposure to chemicals has been adapted for environmental toxicology. Assessments of oxygen consumption rates using the Seahorse XF(e) 24/96 Extracellular Flux Analyzer (Agilent Technologies) can be used to garner insight into toxicant effects at early stages of development. Here we synthesize the current state of the science using high throughput metabolic profiling in zebrafish embryos, and present considerations for those wishing to adopt high throughput methods for mitochondrial bioenergetics into their research. Chemicals that have been investigated in zebrafish using this metabolic platform include herbicides (e.g. paraquat, diquat), industrial compounds (e.g. benzo-[a]-pyrene, tributyltin), natural products (e.g. quercetin), and anti-bacterial chemicals (i.e. triclosan). Some of these chemicals inhibit mitochondrial endpoints in the μM-mM range, and reduce basal respiration, maximum respiration, and spare capacity. We present a theoretical framework for how one can use mitochondrial performance data in zebrafish to categorize chemicals of concern and prioritize mitochondrial toxicants. Noteworthy is that our studies demonstrate that there can be considerable variation in basal respiration of untreated zebrafish embryos due to clutch-specific effects as well as individual variability, and basal oxygen consumption rates (OCR) can vary on average between 100 and 300 pmol/min/embryo. We also compare OCR between chorionated and dechorionated embryos, as both models are employed to test chemicals. After 24 h, dechorionated embryos remain responsive to mitochondrial toxicants, although they show a blunted response to the uncoupling agent carbonylcyanide-4-trifluoromethoxyphenylhydrazone (FCCP); dechorionated embryos are therefore a viable option for investigations into mitochondrial bioenergetics. We present an adverse outcome pathway framework that incorporates endpoints related to mitochondrial bioenergetics. High throughput bioenergetics assays conducted using whole embryos are expected to support adverse outcome pathways for mitochondrial dysfunction.

      PubDate: 2018-04-18T01:47:49Z
      DOI: 10.1016/j.aquatox.2018.03.031
      Issue No: Vol. 199 (2018)
       
  • Transcriptomics provides mechanistic indicators of fluoride toxicology on
           endochondral ossification in the hind limb of Bufo gargarizans
    • Abstract: Publication date: Available online 10 June 2018
      Source:Aquatic Toxicology
      Author(s): Wu Chao, Yuhui Zhang, Lihong Chai, Hongyuan Wang
      Endochondral ossification, the process by which most of the bone is formed, is regulated by many specific groups of molecules and extracellular matrix components. Hind limb of Bufo gargarizans is a model to study endochondral ossification during metamorphosis. Chinese toad (Bufo gargarizans) were exposed to different fluoride concentrations (0, 1, 5, 10 and 20 mg L-1) from G3 to G42. The development of hind limb of B. gargarizans was observed using the double staining methodology. The transcriptome of hind limb of B. gargarizans was conducted using RNA-seq approach, and differentially expressed gene was also validated. In addition, the location of Sox9 and Ihh in the growth cartilage was determined using in situ hybridization. Our results showed that 5 mg L-1 stimulated bone mineralization, while 10 and 20 mg L-1 exposure could inhibit the tibio-fibula, tarsus and metacarpals ossification. Besides, 10 mg F/L treatment could down-regulate Ihh, Sox9, D2, D3, TRα, TRβ, Wnt10, FGF3 and BMP6 expression, while up-regulate ObRb and HHAT mRNA expression in the hind limb of B. gargarizans. Transcript level changes of Ihh, Sox9, D2, D3, TRα, TRβ, Wnt10, FGF3 and BMP6 were consistent with the results of RT-qPCR. In situ hybridization revealed that Ihh was expressed in prehypertrophic chondrocytes, while Sox9 was abundantly expressed in proliferous, prehypertrophic and hypertrophic chondrocytes. However, 10 mg F-/L did not cause any affect in the location of the Ihh and Sox9 mRNA. Therefore, high concentration of fluoride could affect the ossification-related genes mRNA expression and then inhibit the endochondral ossification. The present study thus will greatly contribute to our understanding of the effect of environmental contaminant on ossification in amphibian.

      PubDate: 2018-06-13T10:53:29Z
       
  • Temporal variations in kidney metal concentrations and their implications
           for retinoid metabolism and oxidative stress response in wild yellow perch
           (Perca flavescens)
    • Authors: Michel A. Defo; Louis Bernatchez; Peter G.C. Campbell; Patrice Couture
      Abstract: Publication date: Available online 9 June 2018
      Source:Aquatic Toxicology
      Author(s): Michel A. Defo, Louis Bernatchez, Peter G.C. Campbell, Patrice Couture
      The objective of this study was to determine if temporal variations in tissue metal concentrations are related to biomarkers of retinoid metabolism and oxidative stress responses in juvenile yellow perch (Perca flavescens). To this end, kidney metal (Cd, Cu and Zn) concentrations were measured in fish sampled in spring and fall 2012 in four lakes representing a wide range of water and sediment metal contamination in the Rouyn-Noranda (Quebec) region. Lakes Opasatica and Hélène were considered as reference lakes while lakes Dufault and Marlon were metal-contaminated. Kidney concentrations of Cd, Cu and Zn varied widely between spring and fall in fish from both clean and metal-contaminated lakes. An inter-lake difference in renal metal concentrations was only observed for Cd, with fish from Lake Marlon consistently displaying higher concentrations. In the spring, the concentrations of liver dehydroretinol, dehydroretinyl palmitate and total vitamin A esters were higher in fish sampled in the most contaminated lake.Strong temporal variations in the concentrations of these metabolites, as well as in the percentage of liver free dehydroretinol and the epidermal retinol dehydrogenase 2 transcription levels, were observed in fish living in the most metal-impacted lake, with generally higher values in the spring. In contrast to liver, in muscle, no clear seasonal variations in the concentrations of dehydroretinol, dehydroretinyl stearate or in the percentage of free dehydroretinol were observed in fish captured in the most contaminated lake. Temporal variations of traditional biomarkers of oxidative stress response were also observed in the most metal-impacted lake. For example, the transcription level of the gene encoding Cu/Zn superoxide dismutase-1 in liver and muscle catalase activity of perch sampled in the most contaminated lake were higher in spring than in fall. Positive relationships were found between kidney Cd concentrations and the transcription level of the gene encoding glucose 6-phosphate dehydrogenase, and all forms of retinoid concentrations in liver in spring, except with the percentage of free dehydroretinol where the correlation was negative. Our results translate to a state of stress caused by Cd and illustrate that temporal variations in tissue metal concentrations affect retinoid metabolism and antioxidant capacities in juvenile wild yellow perch. Overall this study contributes to evidence the importance of considering temporal variations when investigating the consequences of metal contamination on the physiology of wild fish.

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.06.007
       
  • New toxicogenetic insights and ranking of the selected pharmaceuticals
           belong to the three different classes: a toxicity estimation to
           confirmation approach
    • Authors: Yi Liu; Muhammad Junaid; Yan Wang; Yu-Mei Tang; Wan-Ping Bian; Wen-Xu Xiong; Hai-Yang Huang; Chun-Di Chen; De-Sheng Pei
      Abstract: Publication date: Available online 9 June 2018
      Source:Aquatic Toxicology
      Author(s): Yi Liu, Muhammad Junaid, Yan Wang, Yu-Mei Tang, Wan-Ping Bian, Wen-Xu Xiong, Hai-Yang Huang, Chun-Di Chen, De-Sheng Pei
      Tetracycline hydrochloride (TH), indomethacin (IM), and bezafibrate (BF) belong to the three different important classes of pharmaceuticals, which are well known for their toxicity and environmental concerns. However, studies are still elusive to highlight the mechanistic toxicity of these pharmaceuticals and rank them using both, the toxicity prediction and confirmation approaches. Therefore, we employed the next generation toxicity testing in 21st century (TOX21) tools and estimated the in vitro/vivo toxic endpoints of mentioned pharmaceuticals, and then confirmed them using in vitro/vivo assays. We found significant resemblance in the results obtained via both approaches, especially in terms of in vivo LC50 s and developmental toxicity that ranked IM as most toxic among the studied pharmaceuticals. However, TH appeared most toxic with the lowest estimated AC50 s, the highest experimental IC50 s and DNA damages in vitro. Contrarily, IM was found as congener with priority concern to activate the Pi3k-Akt-mTOR pathway in vitro at concentrations 1-fold lower (111.80 µM) than that of TH (166.36 µM) and BF (223.59 µM). Further, IM exposure at lower doses (2.79-13.97 µM) depressed the pharmaceuticals detoxification phase I (CYP450 s), phase II (UGTs, SULTs), and phase III pathways (TPs) in zebrafish, whereas, at relatively higher doses, TH (2.08-33.27 µM) and BF (55.28-884.41 µM) partially activated these pathways, which ultimately caused the developmental toxicity in the following order: IM > TH > BF. In addition, we also ranked these pharmaceuticals in terms of their particular toxicity to myogenesis, hematopoiesis, and hepatogenesis in zebrafish embryos. Our results revealed that IM significantly affected myogenesis, hematopoiesis, and hepatogenesis, while TH and BF induced prominent effects on hematopoiesis via significant downregulation of associated genetic markers, such as drl, mpx, and gata2a. Overall, our findings confirmed that IM has higher toxicity than that of TH and BF, therefore, the consumption of these pharmaceuticals should be regulated in the same manner to ensure human and environmental safety.
      Graphical abstract image

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.06.008
       
  • Transcriptome Analysis Reveals Novel Insights Into the Response of
           Low-dose Benzo(a)pyrene Exposure in Male Tilapia
    • Authors: Reyna Cristina Colli-Dula; Xiefan Fang; David Moraga-Amador; Nacira Albornoz-Abud; Roberto Zamora-Bustillos; Ana Conesa; Omar Zapata-Perez; Diego Moreno; Emanuel Hernandez-Nuñez
      Abstract: Publication date: Available online 8 June 2018
      Source:Aquatic Toxicology
      Author(s): Reyna Cristina Colli-Dula, Xiefan Fang, David Moraga-Amador, Nacira Albornoz-Abud, Roberto Zamora-Bustillos, Ana Conesa, Omar Zapata-Perez, Diego Moreno, Emanuel Hernandez-Nuñez
      Despite a wide number of toxicological studies that describe benzo[a]pyrene (BaP) effects, the metabolic mechanisms that underlie these effects in fish are largely unknown. Of great concern is the presence of BaP in aquatic systems, especially those in close proximity to human activity leading to consumption of potentially contaminated foods. BaP is a known carcinogen and it has been reported to have adverse effects on the survival, development and reproduction of fish. The purpose of this study was to investigate if a low dose of BaP can alter genes and key metabolic pathways in the liver and testis in male adult tilapia, and whether these could be associated with biological endpoints disruption. We used both high-throughput RNA-Sequencing to assess whole genome gene expression following repeated intraperitoneal injections of 3 mg/Kg of BaP (every 6 days for 26 days) and morphometric endpoints as indicators of general health. Condition factor (K) along with hepatosomatic and gonadosomatic indices (morphometric parameters) were significantly lower in BaP-treated fish than in controls. BaP exposure induced important changes in the gene expression pattern in liver and testis as revealed by both Pathway and Gene Ontology (GO) analyses. Alterations that were shared by both tissues included arachidonic acid metabolism, androgen receptor to prostate-specific antigen signaling, and insulin-associated effects on lipogenesis. The most salient liver-specific effects included: biological processes involved in detoxification, IL6-associated insulin resistance, mTOR hyperactivation, mitotic cytokinesis, spindle pole and microtubule binding. BaP effects that were confined to the testis included: immune system functions, inflammatory response, estrogen and androgen metabolic pathways. Taken together, gene expression and morphometric end point data indicate that the reproductive success of adult male tilapia could be compromised as a result of BaP exposure. These results constitute new insights on the mechanism of action of low dose BaP in a non-model organism (tilapia).

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.06.005
       
  • RNA-Seq analysis of transcriptome responses in Atlantic cod (Gadus morhua)
           precision-cut liver slices exposed to benzo[a]pyrene and
           17α-ethynylestradiol
    • Authors: Fekadu Yadetie; Xiaokang Zhang; Eileen Marie Hanna; Libe Aranguren-Abadía; Marta Eide; Nello Blaser; Morten Brun; Inge Jonassen; Anders Goksøyr; Odd André Karlsen
      Abstract: Publication date: Available online 7 June 2018
      Source:Aquatic Toxicology
      Author(s): Fekadu Yadetie, Xiaokang Zhang, Eileen Marie Hanna, Libe Aranguren-Abadía, Marta Eide, Nello Blaser, Morten Brun, Inge Jonassen, Anders Goksøyr, Odd André Karlsen
      Polycyclic aromatic hydrocarbons such as benzo[a]pyrene (BaP) that activate the aryl hydrocarbon receptor (Ahr) pathway, and endocrine disruptors acting through the estrogen receptor pathway are among environmental pollutants of major concern. In this work, we exposed Atlantic cod (Gadus morhua) precision-cut liver slices (PCLS) to BaP (10 nM and 1000 nM), ethynylestradiol (EE2) (10 nM and 1000 nM), and equimolar mixtures of BaP and EE2 (10 nM and 1000 nM) for 48 hours, and performed RNA-Seq based transcriptome mapping followed by systematic bioinformatics analyses. Our gene expression analysis showed that several genes were differentially expressed in response to BaP and EE2 treatments in PCLS. Strong up-regulation of genes coding for the cytochrome P450 1a (Cyp1a) enzyme and the Ahr repressor (Ahrrb) was observed in BaP treated PCLS. EE2 treatment of liver slices strongly up-regulated genes coding for precursors of vitellogenin (Vtg) and eggshell zona pellucida (Zp) proteins. As expected, pathway enrichment and network analysis showed that the Ahr and estrogen receptor pathways are among the top affected by BaP and EE2 treatments, respectively. Interestingly, two genes coding for fibroblast growth factor 3 (Fgf3) and fibroblast growth factor 4 (Fgf4) were up-regulated by EE2 in this study. To our knowledge, the fgf3 and fgf4 genes have not previously been described in relation to estrogen signaling in fish liver, and these results suggest the modulation of the FGF signaling pathway by estrogens in fish. The signature expression profiles of top differentially expressed genes in response to the single compound (BaP or EE2) treatment were generally maintained in the expression responses to the equimolar binary mixtures. However, in the mixture-treated groups, BaP appeared to have anti-estrogenic effects as observed by lower number of differentially expressed putative EE2 responsive genes. Our in-depth quantitative analysis of changes in liver transcriptome in response to BaP and EE2, using PCLS tissue culture provides further mechanistic insights into effects of the compounds. Moreover, the analyses demonstrate the usefulness of PCLS in cod for omics experiments.

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.06.003
       
  • Photo-induced antibacterial activity of a porphyrin derivative isolated
           from the harmful dinoflagellate Heterocapsa circularisquama
    • Authors: Li Wencheng; Kichul Cho; Yasuhiro Yamasaki; Satoshi Takeshita; Kiju Hwang; Daekyung Kim; Tatsuya Oda
      Abstract: Publication date: Available online 7 June 2018
      Source:Aquatic Toxicology
      Author(s): Li Wencheng, Kichul Cho, Yasuhiro Yamasaki, Satoshi Takeshita, Kiju Hwang, Daekyung Kim, Tatsuya Oda
      The dinoflagellate Heterocapsa circularisquama is highly toxic to bivalves. However, significant toxicity to finfish species has not been reported. We previously found that H. circularisquama has light-dependent haemolytic agents. Purification and chemical structural analyses revealed that the haemolytic agent H2-a is a porphyrin derivative, which exhibits light-dependent cytotoxicity toward tumour cells. To clarify the biological activity of H2-a further, its antibacterial activities against Gram-positive and Gram-negative bacteria were investigated in this study. A fraction (F5) equivalent to H2-a purified from the methanol extract of H. circularisquama showed potent light-dependent bactericidal activity toward Staphylococcus aureus, and the activity was concentration- and light illumination time-dependent; however, Escherichia coli was highly resistant to F5. Electron microscopic observation suggested that F5 induces morphological changes in S. aureus in a light-dependent manner. Further analysis using other bacterial species showed that the Gram-positive bacterium Bacillus subtilis was more sensitive than the Gram-negative bacteria Pseudomonas aeruginosa and Vibrio alginolyticus. These results indicate that F5 is a photo-induced antibacterial agent with relatively higher specificity to Gram-positive bacteria. Iodometric assay suggested that singlet oxygen was generated from light-illuminated F5. Histidine, a specific singlet oxygen scavenger, markedly inhibited the photosensitising antibacterial activity of F5 against S. aureus, suggesting the involvement of singlet oxygen in antibacterial activity. The antibacterial spectrum of F5 was evidently different from that of 5,10,15,20-tetra (N,N,N-trimethylanilinium) porphyrin tetratosylate, a commercially available porphyrin compound with antibacterial activity. Our results demonstrate that H. circularisquama has a novel antibacterial photosensitiser, a porphyrin derivative, with relatively higher specificity to Gram-positive bacteria. To the best of our knowledge, this is the first study to discover a porphyrin derivative with antibacterial activity in marine microalga.

      PubDate: 2018-06-10T10:48:17Z
      DOI: 10.1016/j.aquatox.2018.06.004
       
  • Chronic environmentally relevant levels of simvastatin disrupt embryonic
           development, biochemical and molecular responses in zebrafish (Danio
           rerio)
    • Authors: Susana Barros; Rosa Montes Benito Quintana Rosario Rodil Ana Ana
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Susana Barros, Rosa Montes, José Benito Quintana, Rosario Rodil, Ana André, Ana Capitão, Joana Soares, Miguel M. Santos, Teresa Neuparth
      Simvastatin (SIM), a hypocholesterolaemic compound, is among the most prescribed pharmaceuticals for cardiovascular disease prevention worldwide. Several studies have shown that acute exposure to SIM causes multiple adverse effects in aquatic organisms. However, uncertainties still remain regarding the chronic effects of SIM in aquatic ecosystems. Therefore, the present study aimed to investigate the effects of SIM in the model freshwater teleost zebrafish (Danio rerio) following a chronic exposure (90 days) to environmentally relevant concentrations ranging from 8 ng/L to 1000 ng/L. This study used a multi-parameter approach integrating distinct ecologically-relevant endpoints, i.e. survival, growth, reproduction and embryonic development, with biochemical markers (cholesterol and triglycerides). Real Time PCR was used to analyse the transcription levels of key genes involved in the mevalonate pathway (hmgcra, cyp51, and dhcr7). Globally, SIM induced several effects that did not follow a dose-response relationship; embryonic development, biochemical and molecular markers, were significantly impacted in the lower concentrations, 8 ng/L, 40 ng/L and/or 200 ng/L, whereas no effects were recorded for the highest tested SIM levels (1000 ng/L). Taken together, these findings expand our understanding of statin effects in teleosts, demonstrating significant impacts at environmentally relevant concentrations and highlight the importance of addressing the effects of chemicals under chronic low-level concentrations.
      Graphical abstract image

      PubDate: 2018-06-07T10:40:01Z
       
  • Immune response induced by major environmental pollutants through altering
           neutrophils in zebrafish larvae
    • Authors: Hongyan Xiaoyan; Zhang Hankun Caixia Xiao-Jing Huo Li-Ping Hou Zhiyuan
      Abstract: Publication date: Available online 6 June 2018
      Source:Aquatic Toxicology
      Author(s): Hongyan Xu, Xiaoyan Zhang, Hankun Li, Caixia Li, Xiao-Jing Huo, Li-Ping Hou, Zhiyuan Gong
      Environmental pollutants may cause adverse effects on the immune system of aquatic organisms. However, the cellular effects of pollutants on fish immune system are largely unknown. Here, we exploited the transgenic zebrafish Tg(lysC:DsRed2) larva as a preliminary screening system to evaluate the potential inflammatory effects of environmental pollutants. Tg(lysC:DsRED2) larvae aged 7-day-postfertilization (7 dpf) were treated with selected environmental chemicals for 24 hours (24 h) and the number of neutrophils were quantified using both image analysis and fluorescence activated cell sorting (FACS). We found that the numbers of neutrophils in the Tg(lysC:DsRED2) larvae were significantly increased by most of the organic chemicals tested, including E2 (17β-estradiol), BPA (Bisphenol-A), NDEA (N-nitrosodiethylamine), 4-NP (4-Nitrophenol) and Lindane (γ-hexachlorocyclohexane). Neutrophil numbers were also increased by all the metals tested (Na2HAsO4· 7H2O, Pb(NO3)2, HgCl2, CdCl2, CuSO4·5H2O, ZnSO4, and K2Cr2O7). The only exception was TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), which significantly reduced the number of neutrophils after exposure. Additionally, the transcription of genes (lyz, mpo, tnfα and il8) related to fish immune system were significantly modulated upon exposure to some of the selected chemicals such as E2, TCDD, Cu and Cd. This study revealed that representatives of major categories of environmental pollutants could cause an acute inflammatory response in zebrafish larvae as shown by alterations in the neutrophils, which may imply a common immunotoxicity mechanism for most environmental pollutants. This study has also demonstrated that Tg(lyz:DsRed2) transgenic zebrafish is an excellent tool for screening environmental chemicals with potential inflammatory effects through FACS-facilitated neutrophil counting.

      PubDate: 2018-06-07T10:40:01Z
       
  • PROTEOMIC RESPONSE OF GILL MICROSOMES OF CRASSOSTREA BRASILIANA EXPOSED TO
           DIESEL FUEL WATER-ACCOMMODATED FRACTION
    • Authors: Gabrielle Amaral; Silva Karim Hahn Guilherme Razzera Guilherme Toledo-Silva Maria
      Abstract: Publication date: Available online 6 June 2018
      Source:Aquatic Toxicology
      Author(s): Gabrielle do Amaral e Silva Müller, Karim Hahn Lüchmann, Guilherme Razzera, Guilherme Toledo-Silva, Maria João Bebianno, Maria Risoleta Freire Marques, Afonso Celso Dias Bainy
      Diesel fuel water-accommodated fraction (diesel-WAF) is a complex mixture of organic compounds that may cause harmful effects to marine invertebrates. Expression of microsomal proteins can be changed by oil exposure, causing functional alterations in endoplasmic reticulum (ER). The aim of this study was to investigate changes in protein expression signatures in microsomes of oysterl Crassostrea brasiliana (=C.gasar) gill after exposure to 10% diesel-WAF for 24 and 72 h. Protein expression signatures of gills of oysters exposed to diesel-WAF were compared to those of unexposed oysters using two–dimensional electrophoresis (2-DE) to identify differentially expressed proteins. A total of 458 protein spots with molecular weights between 30–75 kDa were detected by 2-DE in six replicates of exposed oyster proteomes compared to unexposed ones. Fourteen differentially expressed proteins (six up-regulated and eight down-regulated) were identified. They are: proteins related to xenobiotic biotransformation (cytochrome P450 6 A, NADPH-cytochrome P450 reductase); cytoskeleton (α-tubulin, β-tubulin, gelsolin); processing and degradation of proteins pathways (thioredoxin domain-containing protein E3 ubiquitin-protein ligase MIB2); involved in the biosynthesis of glycolipids and glycoproteins (beta-1,3-galactosyltransferase 1); associated with stress responses (glutamate receptor 4 and 14-3-3 protein zeta, corticotropin-releasing factor-binding protein); plasmalogen biosynthesis (fatty acyl-CoA reductase 1), and sodium-and chloride-dependent glycine transporter 2 and glyoxylate reductase/hydroxypyruvate reductase. Different patterns of protein responses were observed between 24 and 72 h-exposed groups. Expression pattern of microsomal proteins provided a first insight on the potential diesel-WAF effects at protein level in microsomal fraction of oyster gills and indicated new potential biomarkers of exposure and effect. The present work can be a basis for future ecotoxicological studies in oysters aiming to elucidate the molecular mechanisms behind diesel-WAF toxicity and for environmental monitoring programs.

      PubDate: 2018-06-07T10:40:01Z
       
  • Accumulation of perfluorobutane sulfonate (PFBS) and impairment of visual
           function in the eyes of marine medaka after a life-cycle exposure
    • Authors: Lianguo Chen; Mirabelle M.P. Tsui Qipeng Shi Chenyan Wang Bingsheng
      Abstract: Publication date: August 2018
      Source:Aquatic Toxicology, Volume 201
      Author(s): Lianguo Chen, Mirabelle M.P. Tsui, Qipeng Shi, Chenyan Hu, Qi Wang, Bingsheng Zhou, Paul K.S. Lam, James C.W. Lam
      As an alternative to perfluorooctane sulfonate (PFOS), increasing usage of perfluorobutane sulfonate (PFBS) has led to ubiquitous presence in the environment. PFBS is also shown to potently disrupt the thyroid endocrine system. Considering the regulation of thyroid hormones in visual development, PFBS is likely to adversely affect the development and function of visual systems, which is a sensitive target of environmental pollutants. Therefore, the present study exposed marine medaka embryos to environmentally realistic concentrations of PFBS (0, 1.0, 2.9 and 9.5 μg/L) for an entire life-cycle. After exposure until sexual maturity, eyes of adult medaka were dissected to directly investigate the ocular accumulation and toxicity of PFBS. For the first time, substantial accumulation of an environmental pollutant (i.e., PFBS) was observed in the eye tissue. PFBS exposure was also found to impair the visual development and function in a sex-dependent manner. In female medaka, weight of eyes was significantly decreased, while content of water was increased, probably resulting in higher intraocular pressure. Multiple neural signaling processes were also disturbed by PFBS life-cycle exposure, including cholinergic, glutamatergic, GABAergic and monoaminergic systems. Increased levels of norepinephrine and epinephrine neurotransmitters may adaptively decrease the intraocular hypertension in female eyes. In addition, proteomic profiling identified the visual proteins of differential expressions (e.g., beta and gamma crystallins, arrestin and lumican), which were significantly associated with visual perception and motor activity of eyes. Overall, this study found that PFBS was able to accumulate in the eyes and induce ocular toxicities. The susceptibility and sex-specific responses of visual systems to environmental pollutants warrants more works for a comprehensive risk assessment.

      PubDate: 2018-05-31T21:30:36Z
       
 
 
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