1
|
Kim J, Jung D, Chatterjee N, Clark B, Nacci D, Kim S, Choi J. Differential DNA methylation and metabolite profiling of Atlantic killifish (Fundulus heteroclitus) from the New Bedford Harbor Superfund site. ECOTOXICOLOGY (LONDON, ENGLAND) 2024; 33:22-33. [PMID: 38182934 PMCID: PMC10830762 DOI: 10.1007/s10646-023-02724-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/13/2023] [Indexed: 01/07/2024]
Abstract
Atlantic killifish (Fundulus heteroclitus) is a valuable model in evolutionary toxicology to study how the interactions between genetic and environmental factors serve the adaptive ability of organisms to resist chemical pollution. Killifish populations inhabiting environmental toxicant-contaminated New Bedford Harbor (NBH) show phenotypes tolerant to polychlorinated biphenyls (PCBs) and differences at the transcriptional and genomic levels. However, limited research has explored epigenetic alterations and metabolic effects in NBH killifish. To identify the involvement of epigenetic and metabolic regulation in the adaptive response of killifish, we investigated tissue- and sex-specific differences in global DNA methylation and metabolomic profiles of NBH killifish populations, compared to sensitive populations from a non-polluted site, Scorton Creek (SC). The results revealed that liver-specific global DNA hypomethylation and differential metabolites were evident in fish from NBH compared with those from SC. The sex-specific differences were not greater than the tissue-specific differences. We demonstrated liver-specific enriched metabolic pathways (e.g., amino acid metabolic pathways converged into the urea cycle and glutathione metabolism), suggesting possible crosstalk between differential metabolites and DNA hypomethylation in the livers of NBH killifish. Additional investigation of methylated gene regions is necessary to understand the functional role of DNA hypomethylation in the regulation of enzyme-encoding genes associated with metabolic processes and physiological changes in NBH populations.
Collapse
Affiliation(s)
- Jiwan Kim
- School of Environmental Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul, 02504, Korea
| | - Dawoon Jung
- Korea Environment Institute, Division of Environmental Health, Sejong, 30147, Korea
| | - Nivedita Chatterjee
- School of Environmental Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul, 02504, Korea
- NanoSafety Group, International Iberian Nanotechnology Laboratory, Av. Mestre Jose Veiga s/n, 4715-330, Braga, Portugal
| | - Bryan Clark
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Atlantic Coastal Environmental Sciences Division, Narragansett, RI, USA
| | - Diane Nacci
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Atlantic Coastal Environmental Sciences Division, Narragansett, RI, USA
| | - Suhkmann Kim
- Department of Chemistry, Center for Proteome Biophysics and Chemistry Institute for Functional Materials, Pusan National University, Busan, 46241, Korea
| | - Jinhee Choi
- School of Environmental Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul, 02504, Korea.
| |
Collapse
|
2
|
Zeng L, Wang YH, Song W, Ai CX, Liu ZM, Yu MH, Zou WG. Different effects of continuous and pulsed Benzo[a]pyrene exposure on metabolism and antioxidant defense of large yellow croaker: Depend on exposure duration. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 263:115370. [PMID: 37586193 DOI: 10.1016/j.ecoenv.2023.115370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/07/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
This study aims to compare differential effects of continuous and pulsed BaP exposures on metabolism and antioxidant defense in the liver of large yellow croaker. Fish were subjected to BaP for 4 days and 36 days in three exposure regimes with the same time-averaged concentration of BaP: 4 μg/L BaP continuously, 8 μg/L BaP for 24 h every other day or 16 μg/L BaP for 24 h every 4 days. Our results showed that compared to pulsed BaP exposures, continuous BaP exposure reduced BaP metabolism (CYP1A, CYP3A and AHR transcriptional expressions, GSH content, GSH/GSSG ratio, EROD and GST activities) and antioxidant defense (T-SOD activity) on day 4, resulting to the increases in MDA and PC contents, indicating that continuous BaP exposure induced more severe oxidative damage during the early stage of exposure. But continuous BaP exposure reduced MDA and PC contents by improving BaP metabolism and antioxidant defense during the late stage of exposure. CYP1B transcriptional expression and CAT activity were unsuitable biomarkers of both continuous and pulsed BaP exposures. In conclusion, our results demonstrated differential effects of continuous and pulsed exposures on BaP metabolism and antioxidant responses, which were depend on exposure duration.
Collapse
Affiliation(s)
- Lin Zeng
- College of Food and Biological Engineering, Bengbu University, Bengbu 233030, PR China.
| | - Yong-Hong Wang
- College of Food and Biological Engineering, Bengbu University, Bengbu 233030, PR China
| | - Wei Song
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, PR China; Joint Laboratory for Deep Blue Fishery Engineering, Qingdao 266237, PR China.
| | - Chun-Xiang Ai
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, PR China
| | - Zi-Ming Liu
- College of Ecology, Lishui University, Lishui 323000, PR China
| | - Min-Hui Yu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, PR China
| | - Wei-Guang Zou
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, PR China
| |
Collapse
|
3
|
Xie S, Feng Y, Zhou A, Lu Z, JixingZou. Comparative analysis of two new zebrafish models: The cyp1a low-expression line and cyp1a knockout line under PAHs exposure. Gene 2023; 869:147391. [PMID: 36966979 DOI: 10.1016/j.gene.2023.147391] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/17/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
Cytochrome P450 1 (CYP1) is an important enzyme family involved in the metabolism of pollutants, and used as a biomarker to monitor environmental pollution. In this study, a fluorescence-labeled cyp1a zebrafish line, named as KI (cyp1a+/+-T2A-mCherry) (KICM), was originally constructed to monitor dioxin-like compounds in the environment. However, the cyp1a gene expression in the KICM line was inhibited by the fluorescence labeling, thus leading to a significantly increased sensitivity of KICM zebrafish line to PAHs. Then, a cyp1a knockout zebrafish line, named KOC, were constructed for comparative analysis with the cyp1a low-expression line. Interestingly, knockout of the cyp1a gene did not increase the sensitivity of zebrafish to PAHs as significantly as the cyp1a low-expression line. So, the expression levels of related genes in the aryl hydrocarbon receptor pathway were analyzed and the results showed that the expression level of cyp1b in KOC group was significantly higher than that of wild type and KICM under the same PAH exposure. This indicated that the effect of losing cyp1a was compensated by inducing expression of cyp1b. In conclusion, two new zebrafish models including cyp1a low-expression line and cyp1a knockout line were constructed in this study, which may provide a convenient model for subsequent studies on the toxicity mechanism of PAHs and the role of cyp1a in detoxification.
Collapse
|
4
|
Wilson LB, McClure RS, Waters KM, Simonich MT, Tanguay RL. Concentration-response gene expression analysis in zebrafish reveals phenotypically-anchored transcriptional responses to retene. FRONTIERS IN TOXICOLOGY 2022; 4:950503. [PMID: 36093370 PMCID: PMC9453431 DOI: 10.3389/ftox.2022.950503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants and are associated with human disease. Canonically, many PAHs induce toxicity via activation of the aryl hydrocarbon receptor (AHR) pathway. While the interaction between PAHs and the AHR is well-established, understanding which AHR-regulated transcriptional effects directly result in observable phenotypes and which are adaptive or benign is important to better understand PAH toxicity. Retene is a frequently detected PAH in environmental sampling and has been associated with AHR2-dependent developmental toxicity in zebrafish, though its mechanism of toxicity has not been fully elucidated. To interrogate transcriptional changes causally associated with retene toxicity, we conducted whole-animal RNA sequencing at 48 h post-fertilization after exposure to eight retene concentrations. We aimed to identify the most sensitive transcriptomic responses and to determine whether this approach could uncover gene sets uniquely differentially expressed at concentrations which induce a phenotype. We identified a concentration-response relationship for differential gene expression in both number of differentially expressed genes (DEGs) and magnitude of expression change. Elevated expression of cyp1a at retene concentrations below the threshold for teratogenicity suggested that while cyp1a expression is a sensitive biomarker of AHR activation, it may be too sensitive to serve as a biomarker of teratogenicity. Genes differentially expressed at only non-teratogenic concentrations were enriched for transforming growth factor-β (TGF-β) signaling pathway disruption while DEGs identified at only teratogenic concentrations were significantly enriched for response to xenobiotic stimulus and reduction-oxidation reaction activity. DEGs which spanned both non-teratogenic and teratogenic concentrations showed similar disrupted biological processes to those unique to teratogenic concentrations, indicating these processes were disrupted at low exposure concentrations. Gene co-expression network analysis identified several gene modules, including those associated with PAHs and AHR2 activation. One, Module 7, was strongly enriched for AHR2-associated genes and contained the strongest responses to retene. Benchmark concentration (BMC) of Module seven genes identified a median BMC of 7.5 µM, nearly the highest retene concentration with no associated teratogenicity, supporting the hypothesis that Module seven genes are largely responsible for retene toxicity.
Collapse
Affiliation(s)
- Lindsay B. Wilson
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, OR, United States
| | - Ryan S. McClure
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Katrina M. Waters
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, OR, United States
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Michael T. Simonich
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, OR, United States
| | - Robyn L. Tanguay
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, OR, United States
- *Correspondence: Robyn L. Tanguay,
| |
Collapse
|
5
|
Fang J, Dong S, Boogaard PJ, Rietjens IMCM, Kamelia L. Developmental toxicity testing of unsubstituted and methylated 4- and 5-ring polycyclic aromatic hydrocarbons using the zebrafish embryotoxicity test. Toxicol In Vitro 2022; 80:105312. [PMID: 35033653 DOI: 10.1016/j.tiv.2022.105312] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/20/2021] [Accepted: 01/10/2022] [Indexed: 01/29/2023]
Abstract
The present study evaluates the in vitro developmental toxicity of 4- and 5-ring PAHs including benz[a]anthracene and benzo[a]pyrene and six of their monomethylated congeners, and dibenz[a,h]anthracene using the zebrafish embryotoxicity test (ZET). In general, the tested PAHs induced various developmental effects in the zebrafish embryos including unhatched embryos, no movement and circulation, yolk sac and pericardial edemas, deformed body shape, and cumulative mortality at 96 h post fertilization (hpf). The alkyl substituent on different positions of the aromatic ring of the PAHs appeared to change their in vitro developmental toxicity. Comparison to a previously reported molecular docking study showed that the methyl substituents may affect the interaction of the PAHs with the aryl hydrocarbon receptor (AhR) which is known to play a role in the developmental toxicity of some PAHs. Taken together, our results show that methylation can either increase or decrease the developmental toxicity of PAHs and suggest this may relate to effects on the molecular dimensions and resulting consequences for interactions with the AhR.
Collapse
Affiliation(s)
- Jing Fang
- Division of Toxicology, Wageningen University and Research, 6708, WE, Wageningen, the Netherlands.
| | - Shutong Dong
- Division of Toxicology, Wageningen University and Research, 6708, WE, Wageningen, the Netherlands
| | - Peter J Boogaard
- Division of Toxicology, Wageningen University and Research, 6708, WE, Wageningen, the Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University and Research, 6708, WE, Wageningen, the Netherlands
| | - Lenny Kamelia
- Shell Health, Shell International B.V., 2596, HR, The Hague, the Netherlands
| |
Collapse
|
6
|
Alexandre-Moreno S, Bonet-Fernández JM, Atienzar-Aroca R, Aroca-Aguilar JD, Escribano J. Null cyp1b1 Activity in Zebrafish Leads to Variable Craniofacial Defects Associated with Altered Expression of Extracellular Matrix and Lipid Metabolism Genes. Int J Mol Sci 2021; 22:ijms22126430. [PMID: 34208498 PMCID: PMC8234340 DOI: 10.3390/ijms22126430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary CYP1B1 is a cytochrome P450 monooxygenase involved in oxidative metabolism of different endogenous lipids and drugs. The loss of function (LoF) of this gene underlies many cases of recessive primary congenital glaucoma (PCG), an infrequent disease and a common cause of infantile loss of vision in children. To the best of our knowledge, this is the first study to generate a cyp1b1 knockout zebrafish model. The zebrafish line did not exhibit glaucoma-related phenotypes; however, adult mutant zebrafish presented variable craniofacial alterations, including uni- or bilateral craniofacial alterations with incomplete penetrance and variable expressivity. Transcriptomic analyses of seven-dpf cyp1b1-KO zebrafish revealed differentially expressed genes related to extracellular matrix and cell adhesion, cell growth and proliferation, lipid metabolism and inflammation. Overall, this study provides evidence for the complexity of the phenotypes and molecular pathways associated with cyp1b1 LoF, as well as for the dysregulation of extracellular matrix gene expression as one of the mechanisms underlying cyp1b1 disruption-associated pathogenicity. Abstract CYP1B1 loss of function (LoF) is the main known genetic alteration present in recessive primary congenital glaucoma (PCG), an infrequent disease characterized by delayed embryonic development of the ocular iridocorneal angle; however, the underlying molecular mechanisms are poorly understood. To model CYP1B1 LoF underlying PCG, we developed a cyp1b1 knockout (KO) zebrafish line using CRISPR/Cas9 genome editing. This line carries the c.535_667del frameshift mutation that results in the 72% mRNA reduction with the residual mRNA predicted to produce an inactive truncated protein (p.(His179Glyfs*6)). Microphthalmia and jaw maldevelopment were observed in 23% of F0 somatic mosaic mutant larvae (144 hpf). These early phenotypes were not detected in cyp1b1-KO F3 larvae (144 hpf), but 27% of adult (four months) zebrafish exhibited uni- or bilateral craniofacial alterations, indicating the existence of incomplete penetrance and variable expressivity. These phenotypes increased to 86% in the adult offspring of inbred progenitors with craniofacial defects. No glaucoma-related phenotypes were observed in cyp1b1 mutants. Transcriptomic analyses of the offspring (seven dpf) of cyp1b1-KO progenitors with adult-onset craniofacial defects revealed functionally enriched differentially expressed genes related to extracellular matrix and cell adhesion, cell growth and proliferation, lipid metabolism (retinoids, steroids and fatty acids and oxidation–reduction processes that include several cytochrome P450 genes) and inflammation. In summary, this study shows the complexity of the phenotypes and molecular pathways associated with cyp1b1 LoF, with species dependency, and provides evidence for the dysregulation of extracellular matrix gene expression as one of the mechanisms underlying the pathogenicity associated with cyp1b1 disruption.
Collapse
Affiliation(s)
- Susana Alexandre-Moreno
- Área de Genética, Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, 02006 Albacete, Spain; (S.A.-M.); (J.-M.B.-F.); (R.A.-A.)
- Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality (OFTARED), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Juan-Manuel Bonet-Fernández
- Área de Genética, Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, 02006 Albacete, Spain; (S.A.-M.); (J.-M.B.-F.); (R.A.-A.)
- Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality (OFTARED), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Raquel Atienzar-Aroca
- Área de Genética, Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, 02006 Albacete, Spain; (S.A.-M.); (J.-M.B.-F.); (R.A.-A.)
- Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality (OFTARED), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - José-Daniel Aroca-Aguilar
- Área de Genética, Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, 02006 Albacete, Spain; (S.A.-M.); (J.-M.B.-F.); (R.A.-A.)
- Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality (OFTARED), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (J.-D.A.-A.); (J.E.)
| | - Julio Escribano
- Área de Genética, Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, 02006 Albacete, Spain; (S.A.-M.); (J.-M.B.-F.); (R.A.-A.)
- Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality (OFTARED), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (J.-D.A.-A.); (J.E.)
| |
Collapse
|
7
|
Sørhus E, Donald CE, da Silva D, Thorsen A, Karlsen Ø, Meier S. Untangling mechanisms of crude oil toxicity: Linking gene expression, morphology and PAHs at two developmental stages in a cold-water fish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143896. [PMID: 33316527 DOI: 10.1016/j.scitotenv.2020.143896] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Early life stages of fish are highly sensitive to crude oil exposure and thus, short term exposures during critical developmental periods could have detrimental consequences for juvenile survival. Here we administered crude oil to Atlantic haddock (Melanogrammus aeglefinus) in short term (3-day) exposures at two developmental time periods: before first heartbeat, from gastrulation to cardiac cone stage (early), and from first heartbeat to one day before hatching (late). A frequent sampling regime enabled us to determine immediate PAH uptake, metabolite formation and gene expression changes. In general, the embryotoxic consequences of an oil exposure were more severe in the early exposure animals. Oil droplets on the eggshell resulted in severe cardiac and craniofacial abnormalities in the highest treatments. Gene expression changes of Cytochrome 1 a, b, c and d (cyp1a, b, c, d), Bone morphogenetic protein 10 (bmp10), ABC transporter b1 (abcb1) and Rh-associated G-protein (rhag) were linked to PAH uptake, occurrence of metabolites of phenanthrene and developmental and functional abnormalities. We detected circulation-independent, oil-induced gene expression changes and separated phenotypes linked to proliferation, growth and disruption of formation events at early and late developmental stages. Changes in bmp10 expression suggest a direct oil-induced effect on calcium homeostasis. Localized expression of rhag propose an impact on osmoregulation. Severe eye abnormalities were linked to possible inappropriate overexpression of cyp1b in the eyes. This study gives an increased knowledge about developmentally dependent effects of crude oil toxicity. Thus, our findings provide more knowledge and detail to new and several existing adverse outcome pathways of crude oil toxicity.
Collapse
Affiliation(s)
- Elin Sørhus
- Institute of Marine Research, Bergen, Norway.
| | | | - Denis da Silva
- Northwest Fisheries Science Center (NOAA), 2725 Montlake Blvd. East, Seattle, WA 98112-2097, USA
| | | | | | | |
Collapse
|
8
|
Roy MA, Duche PR, Timme-Laragy AR. The sulfate metabolite of 3,3'-dichlorobiphenyl (PCB-11) impairs Cyp1a activity and increases hepatic neutral lipids in zebrafish larvae (Danio rerio). CHEMOSPHERE 2020; 260:127609. [PMID: 32693259 PMCID: PMC7530052 DOI: 10.1016/j.chemosphere.2020.127609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 05/25/2023]
Abstract
The environmental contaminant 3,3'-dichlorobiphenyl (PCB-11) is widely detected in environmental samples, and this parent compound along with its metabolites 4-OH-PCB-11 and 4-PCB-11-Sulfate are detected in human serum. Our previous research in zebrafish (Danio rerio) embryos shows exposure to 20 μM PCB-11 inhibits Cyp1a enzyme activity and perturbs lipid metabolism pathways. In this study, wildtype AB embryos underwent acute exposures from 1 to 4 days post fertilization (dpf) to 0.002-20 μM 4-OH-PCB-11 or 0.2-20 μM 4-PCB-11-Sulfate, with and without co-exposures to 100 μg/L benzo[a]pyrene (B[a]P) or 5 nM 3,3',4,4',5-pentachlorobiphenyl (PCB-126), and were assessed for in vivo EROD activity and morphometrics. Chronic exposures from 1 to 15 dpf to assess lipid accumulation using Oil-Red-O staining were also conducted with 0.2 μM parent or metabolite compounds, alongside a co-exposure experiment of 0.002-0.2 μM 4-PCB-11-Sulfate and 10 μg/L B[a]P. For acute experiments, 2 and 20 μM 4-OH-PCB-11 was lethal but no Cyp1a or morphological effects were observed at lower concentrations; 20 μM 4-PCB-11-Sulfate significantly lowered the Cyp1a activity of B[a]P and PCB-126 but did not alter morphological development. For chronic experiments, 0.2 μM 4-PCB-11-Sulfate significantly increased lipid accumulation 30% in single exposures and 44% in co-exposures with B[a]P. Further long-term studies would better elucidate the effects of this contaminant, particularly in the context of environmentally-relevant mixtures.
Collapse
Affiliation(s)
- Monika A Roy
- Department of Environmental Health Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Perseverance R Duche
- Department of Environmental Health Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Alicia R Timme-Laragy
- Department of Environmental Health Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
| |
Collapse
|
9
|
Shankar P, Dasgupta S, Hahn ME, Tanguay RL. A Review of the Functional Roles of the Zebrafish Aryl Hydrocarbon Receptors. Toxicol Sci 2020; 178:215-238. [PMID: 32976604 PMCID: PMC7706399 DOI: 10.1093/toxsci/kfaa143] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Over the last 2 decades, the zebrafish (Danio rerio) has emerged as a stellar model for unraveling molecular signaling events mediated by the aryl hydrocarbon receptor (AHR), an important ligand-activated receptor found in all eumetazoan animals. Zebrafish have 3 AHRs-AHR1a, AHR1b, and AHR2, and studies have demonstrated the diversity of both the endogenous and toxicological functions of the zebrafish AHRs. In this contemporary review, we first highlight the evolution of the zebrafish ahr genes, and the characteristics of the receptors including developmental and adult expression, their endogenous and inducible roles, and the predicted ligands from homology modeling studies. We then review the toxicity of a broad spectrum of AHR ligands across multiple life stages (early stage, and adult), discuss their transcriptomic and epigenetic mechanisms of action, and report on any known interactions between the AHRs and other signaling pathways. Through this article, we summarize the promising research that furthers our understanding of the complex AHR pathway through the extensive use of zebrafish as a model, coupled with a large array of molecular techniques. As much of the research has focused on the functions of AHR2 during development and the mechanism of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) toxicity, we illustrate the need to address the considerable knowledge gap in our understanding of both the mechanistic roles of AHR1a and AHR1b, and the diverse modes of toxicity of the various AHR ligands.
Collapse
Affiliation(s)
- Prarthana Shankar
- Department of Environmental and Molecular Toxicology, The Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, Oregon 97331
| | - Subham Dasgupta
- Department of Environmental and Molecular Toxicology, The Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, Oregon 97331
| | - Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543
| | - Robyn L Tanguay
- Department of Environmental and Molecular Toxicology, The Sinnhuber Aquatic Research Laboratory, Oregon State University, Corvallis, Oregon 97331
| |
Collapse
|
10
|
Williams AL, Eason J, Chawla B, Bohnsack BL. Cyp1b1 Regulates Ocular Fissure Closure Through a Retinoic Acid-Independent Pathway. Invest Ophthalmol Vis Sci 2017; 58:1084-1097. [PMID: 28192799 PMCID: PMC5308778 DOI: 10.1167/iovs.16-20235] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mutations in the CYP1B1 gene are the most commonly identified genetic causes of primary infantile-onset glaucoma. Despite this disease association, the role of CYP1B1 in eye development and its in vivo substrate remain unknown. In the present study, we used zebrafish to elucidate the mechanism by which cyp1b1 regulates eye development. Methods Zebrafish eye and neural crest development were analyzed using live imaging of transgenic zebrafish embryos, in situ hybridization, immunostaining, TUNEL assay, and methylacrylate sections. Cyp1b1 and retinoic acid (RA) levels were genetically (morpholino oligonucleotide antisense and mRNA) and pharmacologically manipulated to examine gene function. Results Using zebrafish, we observed that cyp1b1 was expressed in a specific spatiotemporal pattern in the ocular fissures of the developing zebrafish retina and regulated fissure patency. Decreased Cyp1b1 resulted in the premature breakdown of laminin in the ventral fissure and altered subsequent neural crest migration into the anterior segment. In contrast, cyp1b1 overexpression inhibited cell survival in the ventral ocular fissure and prevented fissure closure via an RA-independent pathway. Cyp1b1 overexpression also inhibited the ocular expression of vsx2, pax6a, and pax6b and increased the extraocular expression of shha. Importantly, embryos injected with human wild-type but not mutant CYP1B1 mRNA also showed colobomas, demonstrating the evolutionary and functional conservation of gene function between species. Conclusions Cyp1b1 regulation of ocular fissure closure indirectly affects neural crest migration and development through an RA-independent pathway. These studies provide insight into the role of Cyp1b1 in eye development and further elucidate the pathogenesis of primary infantile-onset glaucoma.
Collapse
Affiliation(s)
- Antionette L Williams
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Jessica Eason
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Bahaar Chawla
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Brenda L Bohnsack
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| |
Collapse
|
11
|
Cherr GN, Fairbairn E, Whitehead A. Impacts of Petroleum-Derived Pollutants on Fish Development. Annu Rev Anim Biosci 2017; 5:185-203. [DOI: 10.1146/annurev-animal-022516-022928] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The teleost fish embryo is particularly sensitive to petroleum hydrocarbons (polycyclic aromatic hydrocarbons, PAHs) at two distinct stages of development. The first is early during cleavage stages when PAHs alter normal signaling associated with establishment of the dorsal-ventral axis. This disruption involves the Wnt/β-catenin pathway and results in hyperdorsalized embryos that do not survive to hatching. The second, more sensitive period is during heart development, when oil and PAHs cause abnormal development of the heart as well as cardiac edema and arrhythmia. Even at extremely low levels (ng/L), PAHs cause subtle edema and altered contractility and heart rate, which impair swimming performance. Some PAHs are extremely phototoxic, such that exposures to trace concentrations result in severe membrane damage and mortality in sunlight. The developing fish embryo is a sensitive indicator of petroleum constituents in the environment, and healthy populations of fish likely require limited PAH exposure during development.
Collapse
Affiliation(s)
- Gary N. Cherr
- Bodega Marine Laboratory, University of California, Davis, Bodega Bay, California 94923;,
- Department of Environmental Toxicology, University of California, Davis, California 95616
- Department of Nutrition, University of California, Davis, California 95616
| | - Elise Fairbairn
- Bodega Marine Laboratory, University of California, Davis, Bodega Bay, California 94923;,
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California, Davis, California 95616
| |
Collapse
|
12
|
In vitro CYP1A activity in the zebrafish: temporal but low metabolite levels during organogenesis and lack of gender differences in the adult stage. Reprod Toxicol 2016; 64:50-6. [DOI: 10.1016/j.reprotox.2016.03.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/22/2016] [Accepted: 03/31/2016] [Indexed: 12/18/2022]
|
13
|
Massarsky A, Bone AJ, Dong W, Hinton DE, Prasad GL, Di Giulio RT. AHR2 morpholino knockdown reduces the toxicity of total particulate matter to zebrafish embryos. Toxicol Appl Pharmacol 2016; 309:63-76. [PMID: 27576004 DOI: 10.1016/j.taap.2016.08.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 12/26/2022]
Abstract
The zebrafish embryo has been proposed as a 'bridge model' to study the effects of cigarette smoke on early development. Previous studies showed that exposure to total particulate matter (TPM) led to adverse effects in developing zebrafish, and suggested that the antioxidant and aryl hydrocarbon receptor (AHR) pathways play important roles. This study investigated the roles of these two pathways in mediating TPM toxicity. The study consisted of four experiments. In experiment I, zebrafish embryos were exposed from 6h post fertilization (hpf) until 96hpf to TPM0.5 and TPM1.0 (corresponding to 0.5 and 1.0μg/mL equi-nicotine units) in the presence or absence of an antioxidant (N-acetyl cysteine/NAC) or a pro-oxidant (buthionine sulfoximine/BSO). In experiment II, TPM exposures were performed in embryos that were microinjected with nuclear factor erythroid 2-related factor 2 (Nrf2), AHR2, cytochrome P450 1A (CYP1A), or CYP1B1 morpholinos, and deformities were assessed. In experiment III, embryos were exposed to TPM, and embryos/larvae were collected at 24, 48, 72, and 96hpf to assess several genes associated with the antioxidant and AHR pathways. Lastly, experiment IV assessed the activity and protein levels of CYP1A and CYP1B1 after exposure to TPM. We demonstrate that the incidence of TPM-induced deformities was generally not affected by NAC/BSO treatments or Nrf2 knockdown. In contrast, AHR2 knockdown reduced, while CYP1A or CYP1B1 knockdowns elevated the incidence of some deformities. Moreover, as shown by gene expression the AHR pathway, but not the antioxidant pathway, was induced in response to TPM exposure, providing further evidence for its importance in mediating TPM toxicity.
Collapse
Affiliation(s)
- Andrey Massarsky
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
| | - Audrey J Bone
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Wu Dong
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA; School of Animal Science and Technology, Inner Mongolia Provincial Key Laboratory for Toxicants and Animal Disease, Inner Mongolia University for the Nationalities, Tongliao, Inner Mongolia 028000, China
| | - David E Hinton
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - G L Prasad
- RAI Services Company, Winston-Salem, NC 27101, USA
| | | |
Collapse
|
14
|
Saad M, Cavanaugh K, Verbueken E, Pype C, Casteleyn C, Van Ginneken C, Van Cruchten S. Xenobiotic metabolism in the zebrafish: a review of the spatiotemporal distribution, modulation and activity of Cytochrome P450 families 1 to 3. J Toxicol Sci 2016; 41:1-11. [DOI: 10.2131/jts.41.1] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Moayad Saad
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Kate Cavanaugh
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Evy Verbueken
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Casper Pype
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Christophe Casteleyn
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Chris Van Ginneken
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Steven Van Cruchten
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| |
Collapse
|
15
|
Wu X, Barnhart C, Lein P, Lehmler HJ. Hepatic metabolism affects the atropselective disposition of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) in mice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:616-25. [PMID: 25420130 PMCID: PMC4291784 DOI: 10.1021/es504766p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To understand the role of hepatic vs extrahepatic metabolism in the disposition of chiral PCBs, we studied the disposition of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) and its hydroxylated metabolites (HO-PCBs) in mice with defective hepatic metabolism due to the liver-specific deletion of cytochrome P450 oxidoreductase (KO mice). Female KO and congenic wild type (WT) mice were treated with racemic PCB 136, and levels and chiral signatures of PCB 136 and HO-PCBs were determined in tissues and excreta 3 days after PCB administration. PCB 136 tissue levels were higher in KO compared to WT mice. Feces was a major route of PCB metabolite excretion, with 2,2',3,3',6,6'-hexachlorobiphenyl-5-ol being the major metabolite recovered from feces. (+)-PCB 136, the second eluting PCB 136 atropisomers, was enriched in all tissues and excreta. The second eluting atropisomers of the HO-PCBs metabolites were enriched in blood and liver; 2,2',3,3',6,6'-hexachlorobiphenyl-5-ol in blood was an exception and displayed an enrichment of the first eluting atropisomers. Fecal HO-PCB levels and chiral signatures changed with time and differed between KO and WT mice, with larger HO-PCB enantiomeric fractions in WT compared to KO mice. Our results demonstrate that hepatic and, possibly, extrahepatic cytochrome P450 (P450) enzymes play a role in the disposition of PCBs.
Collapse
Affiliation(s)
- Xianai Wu
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Christopher Barnhart
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, United States
| | - Pamela
J. Lein
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
- Phone: 319 335-4310. Fax: 319 335-4290. E-mail: . Corresponding author address:
Department of Occupational and Environmental
Health, The University of Iowa, University of Iowa Research Park,
#221 IREH, Iowa City, IA 52242-5000
| |
Collapse
|
16
|
Jönsson ME, Kubota A, Timme-Laragy AR, Woodin B, Stegeman JJ. Ahr2-dependence of PCB126 effects on the swim bladder in relation to expression of CYP1 and cox-2 genes in developing zebrafish. Toxicol Appl Pharmacol 2012; 265:166-74. [PMID: 23036320 DOI: 10.1016/j.taap.2012.09.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 09/18/2012] [Accepted: 09/26/2012] [Indexed: 01/01/2023]
Abstract
The teleost swim bladder is assumed a homolog of the tetrapod lung. Both swim bladder and lung are developmental targets of persistent aryl hydrocarbon receptor (AHR(2)) agonists; in zebrafish (Danio rerio) the swim bladder fails to inflate with exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB126). The mechanism for this effect is unknown, but studies have suggested roles of cytochrome P450 1 (CYP1) and cyclooxygenase 2 (Cox-2) in some Ahr-mediated developmental effects in zebrafish. We determined relationships between swim bladder inflation and CYP1 and Cox-2 mRNA expression in PCB126-exposed zebrafish embryos. We also examined effects on β-catenin dependent transcription, histological effects, and Ahr2 dependence of the effect of PCB126 on swim bladder using morpholinos targeting ahr2. One-day-old embryos were exposed to waterborne PCB126 or carrier (DMSO) for 24h and then held in clean water until day 4, a normal time for swim bladder inflation. The effects of PCB126 were concentration-dependent with EC(50) values of 1.4 to 2.0 nM for induction of the CYP1s, 3.7 and 5.1 nM (or higher) for cox-2a and cox-2b induction, and 2.5 nM for inhibition of swim bladder inflation. Histological defects included a compaction of the developing bladder. Ahr2-morpholino treatment rescued the effect of PCB126 (5 nM) on swim bladder inflation and blocked induction of CYP1A, cox-2a, and cox-2b. With 2nM PCB126 approximately 30% of eleutheroembryos(3) failed to inflate the swim bladder, but there was no difference in CYP1 or cox-2 mRNA expression between those embryos and embryos showing inflated swim bladder. Our results indicate that PCB126 blocks swim bladder inflation via an Ahr2-mediated mechanism. This mechanism seems independent of CYP1 or cox-2 mRNA induction but may involve abnormal development of swim bladder cells.
Collapse
Affiliation(s)
- Maria E Jönsson
- Dept. of Environmental Toxicology, Evolutionary Biology, Centre, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden.
| | | | | | | | | |
Collapse
|
17
|
Timme-Laragy AR, Karchner SI, Hahn ME. Gene knockdown by morpholino-modified oligonucleotides in the zebrafish (Danio rerio) model: applications for developmental toxicology. Methods Mol Biol 2012; 889:51-71. [PMID: 22669659 PMCID: PMC4218736 DOI: 10.1007/978-1-61779-867-2_5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The zebrafish (Danio rerio) has long been used as a model for developmental biology, making it an excellent model to use also in developmental toxicology. The many advantages of zebrafish include their small size, prolific spawning, rapid development, and transparent embryos. They can be easily manipulated genetically through the use of transgenic technology and gene knockdown via morpholino-modified antisense oligonucleotides (MOs). Knocking down specific genes to assess their role in the response to toxicant exposure provides a way to further our knowledge of how developmental toxicants work on a molecular and mechanistic level while establishing a relationship between these molecular events and morphological, behavioral, and/or physiological effects (i.e., phenotypic anchoring). In this chapter, we address important considerations for using MOs to study developmental toxicology in zebrafish embryos and provide a protocol for their use.
Collapse
|
18
|
Wills LP, Matson CW, Landon CD, Di Giulio RT. Characterization of the recalcitrant CYP1 phenotype found in Atlantic killifish (Fundulus heteroclitus) inhabiting a Superfund site on the Elizabeth River, VA. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:33-41. [PMID: 20471113 PMCID: PMC2883677 DOI: 10.1016/j.aquatox.2010.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 03/16/2010] [Accepted: 03/27/2010] [Indexed: 05/06/2023]
Abstract
Fundulus heteroclitus (Atlantic killifish) found at the Atlantic Wood Industries Superfund site on the Elizabeth River (ER) in Portsmouth, VA (USA), have been shown to be resistant to the teratogenic effects of creosote-contaminated sediments found at this highly contaminated site. Many of the polycyclic aromatic hydrocarbons (PAHs) found at the ER are known to activate the aryl hydrocarbon receptor (AHR), and are thought to mediate their toxic effects through this pathway. Activation of the AHR results in the induction of several Phase I and II metabolic enzymes. It has been previously shown that the AHR of killifish from the ER are refractory to induction by AHR agonists. To more fully characterize this altered AHR response, we exposed embryos from the ER and from a reference site on King's Creek, VA (KC) to two PAHs, benzo[alpha]pyrene (BaP) and benzo[k]fluoranthene (BkF), and to the dioxin-like compound (DLC), 3,3',4,4',5-pentachlorobiphenyl (PCB126). We compared their developmental and molecular responses by screening the embryos for CYP1A enzyme activity, cardiac deformities, and mRNA expression of CYP1A, CYP1B1, CYP1C1, and AHR2. Basal gene expression of both CYP1A and CYP1B1 was 40% higher in the KC control embryos compared to those from the ER, while AHR2 and CYP1C1 were not significantly different between the populations. Exposure of KC embryos to BaP, BkF, and PCB126 induced CYP1A activity and cardiac deformities. In contrast, CYP1A activity was induced in ER embryos only in response to BkF exposure, although this induction in ER embryos was significantly lower than that observed in KC fish at comparable concentrations. ER embryos did not develop cardiac deformities in response to any of the chemicals tested. CYP1A, CYP1B1 and CYP1C1 mRNA were all significantly induced in the KC embryos after exposure to BaP, BkF and PCB126. Exposure to BaP and BkF in ER embryos resulted in a significant induction of CYP1A mRNA, albeit significantly lower than observed in KC fish. Interestingly, BaP exposure resulted in induction of CYP1B1 at comparable levels in embryos from both populations. CYP1s were not induced in ER embryos in response to PCB126, nor was CYP1C1 for any treatment examined. Additionally, AHR2 was not significantly induced for any of the treatment groups. This study further characterizes the AHR response in killifish, and provides greater insight into the adapted ER phenotype. The ER adaptation involves the suppression of normal AHR-inducible gene expression for all three CYP1 genes, and therefore is likely an alteration in AHR signaling or control.
Collapse
Affiliation(s)
- Lauren P. Wills
- Nicholas School of the Environment, Duke University, Durham, NC 27708
- College of Pharmacy, Medical University of South Carolina, Charleston, SC 29425
| | - Cole W. Matson
- Nicholas School of the Environment, Duke University, Durham, NC 27708
- Center for the Environmental Implications of NanoTechnology (CEINT), Duke University, Durham, NC 27708
| | - Chelsea D. Landon
- Nicholas School of the Environment, Duke University, Durham, NC 27708
- Department of Pathology, Duke University, Durham, NC 27708
| | - Richard T. Di Giulio
- Nicholas School of the Environment, Duke University, Durham, NC 27708
- Corresponding Author: Richard T. Di Giulio Nicholas School of the Environment Duke University Box 90328 Durham, NC 27708-0328 (919) 613-8024
| |
Collapse
|