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Ke T, Rajoo A, Tinkov AA, Skalny AV, Tizabi Y, Rocha JBT, Bowman AB, Aschner M. Intestinal microbiota protects against methylmercury-induced neurotoxicity. Biometals 2024; 37:561-576. [PMID: 37973679 DOI: 10.1007/s10534-023-00554-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/14/2023] [Indexed: 11/19/2023]
Abstract
Methylmercury (MeHg) remains a global public health issue because of its frequent presence in human food sources obtained from the water. The excretion of MeHg in humans occurs slowly with a biological half-time of 32-47 days. Short-term MeHg exposure may cause long-lasting neurotoxicity. The excretion through feces is a major route in the demethylation of MeHg. Accumulating evidence suggests that the intestinal microbiota plays an important role in the demethylation of MeHg, thereby protecting the host from neurotoxic effects. Here, we discuss recent developments on the role of intestinal microbiota in MeHg metabolism, based on in vitro cell culture experiments, experimental animal studies and human investigations. Demethylation by intestinal bacteria is the rate-limiting step in MeHg metabolism and elimination. The identity of bacteria strains responsible for this biotransformation is currently unknown; however, the non-homogenous distribution of intestinal microbiota may lead to different demethylation rates in the intestinal tract. The maintenance of intestinal barrier function by intestinal microbiota may afford protection against MeHg-induced neurotoxicity, which warrant future investigations. We also discuss studies investigating the effects of MeHg exposure on the population structural stability of intestinal microbiota in several host species. Although this is an emerging area in metal toxicity, current research suggests that a change in certain phyla in the intestinal microbiota may indicate MeHg overexposure.
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Affiliation(s)
- Tao Ke
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA
| | - André Rajoo
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Alexey A Tinkov
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia, 119991
- Yaroslavl State University, Yaroslavl, Russia, 150003
- Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia, 460000
| | - Anatoly V Skalny
- IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia, 119991
- Department of Medical Elementology, Peoples' Friendship University of Russia (RUDN University), Moscow, Russia, 117198
| | - Yousef Tizabi
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, 20059, USA
| | - Joao B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, 97105900, RS, Brazil
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, 47907-2051, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue Forchheimer Building, Room 209, Bronx, NY, 10461, USA.
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Martinez-Morata I, Sobel M, Tellez-Plaza M, Navas-Acien A, Howe CG, Sanchez TR. A State-of-the-Science Review on Metal Biomarkers. Curr Environ Health Rep 2023; 10:215-249. [PMID: 37337116 PMCID: PMC10822714 DOI: 10.1007/s40572-023-00402-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE OF REVIEW Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses. RECENT FINDINGS We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.
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Affiliation(s)
- Irene Martinez-Morata
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th Street, 1107, New York, NY, 10032, USA.
| | - Marisa Sobel
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th Street, 1107, New York, NY, 10032, USA
| | - Maria Tellez-Plaza
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Navas-Acien
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th Street, 1107, New York, NY, 10032, USA
| | - Caitlin G Howe
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Tiffany R Sanchez
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th Street, 1107, New York, NY, 10032, USA
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Coe GL, Krout IN, Munro-Ehrlich M, Beamish CR, Vorojeikina D, Colman DR, Boyd EJ, Walk ST, Rand MD. Assessing the role of the gut microbiome in methylmercury demethylation and elimination in humans and gnotobiotic mice. Arch Toxicol 2023; 97:2399-2418. [PMID: 37392210 PMCID: PMC10913183 DOI: 10.1007/s00204-023-03548-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/14/2023] [Indexed: 07/03/2023]
Abstract
The risk of methylmercury (MeHg) toxicity following ingestion of contaminated foodstuffs (e.g., fish) is directly related to the kinetics of MeHg elimination among individuals. Yet, the factors driving the wide range of inter-individual variability in MeHg elimination within a population are poorly understood. Here, we investigated the relationship between MeHg elimination, gut microbiome demethylation activity, and gut microbiome composition using a coordinated human clinical trial and gnotobiotic mouse modeling approach together with metagenomic sequence analysis. We first observed MeHg elimination half-lives (t1/2) ranging from 28 to 90 days across 27 volunteers. Subsequently, we found that ingestion of a prebiotic induced changes in the gut microbiome and mixed effects (increased, decrease, and no effect) on elimination in these same individuals. Nonetheless, elimination rates were found to correlate with MeHg demethylation activity in cultured stool samples. In mice, attempts to remove the microbiome via generation of germ-free (GF) animals or through antibiotic (Abx) treatment both diminished MeHg demethylation to a similar extent. While both conditions substantially slowed elimination, Abx treatment resulted in significantly slower elimination than the GF condition, indicating an additional role for host-derived factors in supporting elimination. Human fecal microbiomes transplanted to GF mice restored elimination rates to that seen in control mice. Metagenomic sequence analysis of human fecal DNA did not identify genes encoding proteins typically involved in demethylation (e.g., merB, organomercury lyase). However, the abundance of several anaerobic taxa, notably Alistipes onderdonkii, were positively correlated with MeHg elimination. Surprisingly, mono-colonization of GF free mice with A. onderdonkii did not restore MeHg elimination to control levels. Collectively, our findings indicate the human gut microbiome uses a non-conventional pathway of demethylation to increase MeHg elimination that relies on yet to be resolved functions encoded by the gut microbes and the hostClinical Trial NCT04060212, prospectively registered 10/1/2019.
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Affiliation(s)
- Genevieve L Coe
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Ian N Krout
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Mason Munro-Ehrlich
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Catherine R Beamish
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Daria Vorojeikina
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Daniel R Colman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Eric J Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Seth T Walk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Matthew D Rand
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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Martins AC, Ferrer B, Tinkov AA, Caito S, Deza-Ponzio R, Skalny AV, Bowman AB, Aschner M. Association between Heavy Metals, Metalloids and Metabolic Syndrome: New Insights and Approaches. TOXICS 2023; 11:670. [PMID: 37624175 PMCID: PMC10459190 DOI: 10.3390/toxics11080670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023]
Abstract
Metabolic syndrome (MetS) is an important public health issue that affects millions of people around the world and is growing to pandemic-like proportions. This syndrome is defined by the World Health Organization (WHO) as a pathologic condition characterized by abdominal obesity, insulin resistance, hypertension, and hyperlipidemia. Moreover, the etiology of MetS is multifactorial, involving many environmental factors, including toxicant exposures. Several studies have associated MetS with heavy metals exposure, which is the focus of this review. Environmental and/or occupational exposure to heavy metals are a major risk, contributing to the development of chronic diseases. Of particular note, toxic metals such as mercury, lead, and cadmium may contribute to the development of MetS by altering oxidative stress, IL-6 signaling, apoptosis, altered lipoprotein metabolism, fluid shear stress and atherosclerosis, and other mechanisms. In this review, we discuss the known and potential roles of heavy metals in MetS etiology as well as potential targeted pathways that are associated with MetS. Furthermore, we describe how new approaches involving proteomic and transcriptome analysis, as well as bioinformatic tools, may help bring about an understanding of the involvement of heavy metals and metalloids in MetS.
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Affiliation(s)
- Airton C. Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Alexey A. Tinkov
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, 150003 Yaroslavl, Russia; (A.A.T.)
- IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
| | - Samuel Caito
- School of Pharmacy, Husson University, Bangor, ME 04401, USA
| | - Romina Deza-Ponzio
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
| | - Anatoly V. Skalny
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, 150003 Yaroslavl, Russia; (A.A.T.)
- IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA;
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA; (A.C.M.)
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5
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Yánez-Jácome GS, Romero-Estévez D, Vélez-Terreros PY, Navarrete H. Total mercury and fatty acids content in selected fish marketed in Quito - Ecuador. A benefit-risk assessment. Toxicol Rep 2023; 10:647-658. [PMID: 37250532 PMCID: PMC10220416 DOI: 10.1016/j.toxrep.2023.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 05/31/2023] Open
Abstract
Total mercury and fatty acids contents were determined in muscles of croaker, snapper, dolphinfish, blue marlin, and shark, from different markets in the Metropolitan District of Quito, Ecuador. Fifty-five samples were collected and analyzed for total mercury using cold vapor atomic fluorescence spectrometry, and the fatty acids were analyzed using gas chromatography equipped with a flame ionization detector. The lowest total mercury levels were found in snapper [0.041 µg·g-1 wet weight (ww)] while blue marlin showed the highest (5.883 µg·g-1 ww). EPA + DHA ranged from 1.0 mg·g-1 in snapper to 2.4 mg·g-1 in shark. A high omega-3/omega-6 ratio was found for all fish types; however, the HQEFA for the benefit-risk ratio was above 1, suggesting an evident risk to human health. Based on our results, consumption of croaker and dolphinfish is recommended up to one serving per week, considering the importance of EFAs intake and avoiding fish with elevated MeHg content. Therefore, Ecuadorian authorities could enhance public standards for seafood safety and develop consumer advice for pregnant women and young children to determine good fish choices or those to avoid.
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Affiliation(s)
- Gabriela S. Yánez-Jácome
- Centro de Estudios Aplicados en Química, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
| | - David Romero-Estévez
- Centro de Estudios Aplicados en Química, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
| | - Pamela Y. Vélez-Terreros
- Centro de Estudios Aplicados en Química, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
| | - Hugo Navarrete
- Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
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6
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Gut as the target tissue of mercury and the extraintestinal effects. Toxicology 2023; 484:153396. [PMID: 36521575 DOI: 10.1016/j.tox.2022.153396] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is harmful to the environment and human health. The gut plays important roles as the biological, chemical, mechanical, and immune barriers in animals and human beings. It has been known that Hg can be absorbed and methylated/demethylated in the gut, on the other hand, the impacts of Hg to the gut (especially the gut microbiota) is less studied. This review paper summarizes the impacts of inorganic Hg (IHg) and methyl Hg (MeHg) on gut barriers and the extraintestinal effects (damage to other organs such as the liver and brain). Both IHg and MeHg were found to cause intestinal microbial disorders, abnormal metabolites production, tight junction damage, and immune responses in the gut. The damage to the gut also contributed to the extraintestinal effects like the hepatotoxicity by IHg and the neurotoxicity by MeHg. In all, it is proposed that the gut should be considered as an important target tissue of Hg exposure, and the regulation of gut microbiota may have the potential for the prevention and control of the toxicity of Hg.
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7
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Krout IN, Scrimale T, Rand MD. Targeted Intracellular Demethylation of Methylmercury Enhances Elimination Kinetics and Reduces Developmental Toxicity in Transgenic Drosophila. Toxicol Sci 2022; 190:146-157. [PMID: 36200918 PMCID: PMC9960040 DOI: 10.1093/toxsci/kfac105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methylmercury (MeHg) persists today as a priority public health concern. Mechanisms influencing MeHg metabolism, kinetics, and toxicity outcomes are therefore essential knowledge for informing exposure risks. Evidence points to different toxic potencies of MeHg and inorganic mercury (Hg2+), highlighting the role for biotransformation (demethylation) in regulating MeHg toxicokinetics/dynamics. Whereas microbial MeHg demethylation in the gut is seen to influence elimination kinetics, the potential for systemic demethylation in tissues and target organs to influence MeHg toxicity remains uncertain. To investigate the consequences of systemic MeHg demethylation across development, we engineered transgenic Drosophila to express the bacterial organomercurial lyase enzyme (merB) in a targeted and tissue-specific manner. With all combinations of merB-induced demethylation, ubiquitously (via an actin promoter) or in a tissue-specific manner (ie, gut, muscle, neurons), we observe a rescue of MeHg-induced eclosion failure at the pupal to adult transition. In MeHg-fed larvae with ubiquitous or targeted (gut and muscle) merB expression, we see a significant decrease in MeHg body burden at the pupal stage relative to control flies. We also observe a significant increase in the MeHg elimination rate with merB demethylation induced in adults (control, t1/2 = 7.2 days; merB flies, t1/2 = 3.1 days). With neuronal-specific merB expression, we observe a rescue of MeHg-induced eclosion failure without a decrease in Hg body burden, but a redistribution of Hg away from the brain. These results demonstrate the previously unidentified potential for intracellular MeHg demethylation to promote transport and elimination of Hg, and reduce developmental MeHg toxicity. Impact Statement: These findings demonstrate the potential for MeHg demethylation in situ to contribute significantly to the MeHg elimination and distribution kinetics of whole animals and thereby affords a means of protection against the toxic insult of MeHg. Therefore, this study reveals important insight into processes that can determine an individual's resistance or susceptibility to MeHg and provides rationale for therapies targeting a novel metabolism-based pathways to alleviate toxicity risk stemming from MeHg exposure.
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Affiliation(s)
- Ian N Krout
- To whom correspondence should be addressed. E-mail: and E-mail:
| | - Thomas Scrimale
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14620, USA
| | - Matthew D Rand
- To whom correspondence should be addressed. E-mail: and E-mail:
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8
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Li ML, Kwon SY, Poulin BA, Tsui MTK, Motta LC, Cho M. Internal Dynamics and Metabolism of Mercury in Biota: A Review of Insights from Mercury Stable Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9182-9195. [PMID: 35723432 PMCID: PMC9261262 DOI: 10.1021/acs.est.1c08631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Monitoring mercury (Hg) levels in biota is considered an important objective for the effectiveness evaluation of the Minamata Convention. While many studies have characterized Hg levels in organisms at multiple spatiotemporal scales, concentration analyses alone often cannot provide sufficient information on the Hg exposure sources and internal processes occurring within biota. Here, we review the decadal scientific progress of using Hg isotopes to understand internal processes that modify the speciation, transport, and fate of Hg within biota. Mercury stable isotopes have emerged as a powerful tool for assessing Hg sources and biogeochemical processes in natural environments. A better understanding of the tissue location and internal mechanisms leading to Hg isotope change is key to assessing its use for biomonitoring. We synthesize the current understanding and uncertainties of internal processes leading to Hg isotope fractionation in a variety of biota, in a sequence of better to less studied organisms (i.e., birds, marine mammals, humans, fish, plankton, and invertebrates). This review discusses the opportunities and challenges of using certain forms of biota for Hg source monitoring and the need to further elucidate the physiological mechanisms that control the accumulation, distribution, and toxicity of Hg in biota by coupling new techniques with Hg stable isotopes.
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Affiliation(s)
- Mi-Ling Li
- School
of Marine Science and Policy, University
of Delaware, 201 Robinson Hall, Newark, Delaware 19716, United
States
| | - Sae Yun Kwon
- Division
of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro,
Nam-Gu, Pohang 37673, South Korea
- Institute
for Convergence Research and Education in Advanced Technology, Yonsei University, 85 Songdogwahak-Ro, Yeonsu-Gu, Incheon 21983, South Korea
| | - Brett A. Poulin
- Department
of Environmental Toxicology, University
of California Davis, One Shields Avenue, Davis, California 95616, United States
| | - Martin Tsz-Ki Tsui
- School
of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR 999077, China
| | - Laura C. Motta
- Department
of Chemistry, University at Buffalo, 359 Natural Sciences Complex, Buffalo, New York 14260-3000, United States
| | - Moonkyoung Cho
- Division
of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro,
Nam-Gu, Pohang 37673, South Korea
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Rodiouchkina K, Rodushkin I, Goderis S, Vanhaecke F. Longitudinal isotope ratio variations in human hair and nails. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152059. [PMID: 34863743 DOI: 10.1016/j.scitotenv.2021.152059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 06/13/2023]
Abstract
Due to the straightforward and non-invasive sampling, ease of transport and long-term storage and access to time-resolved information, determination of element concentrations and isotope ratios in hair and nails finds increasing use. Multi-isotopic information preserved in keratinous tissues allows one to reveal dietary, physiological and environmental influences, but progress in this area is still limited by complicated and time-consuming analytical procedures and challenges in accuracy assessment. In this study, longitudinal distributions of δ34S, 87Sr/86Sr, 207,208Pb/206Pb, δ66Zn, δ56Fe, δ65Cu, δ26Mg, and δ114Cd were obtained for hair and nails collected from nine subjects with different age, biological sex, diet and/or place of residence. For S and Zn, the distribution along hair strands revealed a trend towards a heavier isotopic signature from the proximal to the distal end, with a maximum difference within the hair of a single subject of 1.2‰ (Δ34S) and 0.4‰ (Δ66Zn). For Fe, Cu, Mg and Cd, a shift towards either a lighter (Cu) or heavier (Fe, Mg and Cd) isotopic composition is accompanied by increasing concentration towards the distal hair end, indicating possible isotope fractionation during deposition or external contamination with a different isotopic composition. Pb and Sr isotope ratios are relatively stable throughout the hair strands despite notable concentration increases towards the distal end, likely reflecting external contamination. The isotopic composition of Sr points to tap water as a probable main source, explaining the relative stability of the ratio for individuals from the same geographical location. For Pb, isotopic compositions suggest tap water and/or indoor dust as possible sources. Similar δ34S, 87Sr/86Sr, 207,208Pb/206Pb, δ66Zn, δ56Fe, and δ65Cu observed for hair, fingernails and toenails sampled from the same individual suggest that keratinous tissues are conservative receivers of internal and external inputs and can be used complementary. Seasonal variation in δ34S, 207,208Pb/206Pb, and δ65Cu was observed for fingernails.
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Affiliation(s)
- Katerina Rodiouchkina
- Ghent University, Department of Chemistry, Atomic and Mass Spectrometry (A&MS) research group, Campus Sterre, Krijgslaan 281 - S12, 9000 Ghent, Belgium
| | - Ilia Rodushkin
- ALS Scandinavia AB, ALS Laboratory Group, Aurorum 10, S-977 75 Luleå, Sweden
| | - Steven Goderis
- Vrije Universiteit Brussel, Department of Chemistry, Analytical, Environmental and Geo-Chemistry (AMGC) research group, Pleinlaan 2, 1050 Brussels, Belgium
| | - Frank Vanhaecke
- Ghent University, Department of Chemistry, Atomic and Mass Spectrometry (A&MS) research group, Campus Sterre, Krijgslaan 281 - S12, 9000 Ghent, Belgium.
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10
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Methylmercury and Polycyclic Aromatic Hydrocarbons in Mediterranean Seafood: A Molecular Anthropological Perspective. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app112311179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Eating seafood has numerous health benefits; however, it constitutes one of the main sources of exposure to several harmful environmental pollutants, both of anthropogenic and natural origin. Among these, methylmercury and polycyclic aromatic hydrocarbons give rise to concerns related to their possible effects on human biology. In the present review, we summarize the results of epidemiological investigations on the genetic component of individual susceptibility to methylmercury and polycyclic aromatic hydrocarbons exposure in humans, and on the effects that these two pollutants have on human epigenetic profiles (DNA methylation). Then, we provide evidence that Mediterranean coastal communities represent an informative case study to investigate the potential impact of methylmercury and polycyclic aromatic hydrocarbons on the human genome and epigenome, since they are characterized by a traditionally high local seafood consumption, and given the characteristics that render the Mediterranean Sea particularly polluted. Finally, we discuss the challenges of a molecular anthropological approach to this topic.
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11
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Ke T, Tinkov AA, Skalny AV, Bowman AB, Rocha JBT, Santamaria A, Aschner M. Developmental exposure to methylmercury and ADHD, a literature review of epigenetic studies. ENVIRONMENTAL EPIGENETICS 2021; 7:dvab014. [PMID: 34881051 PMCID: PMC8648069 DOI: 10.1093/eep/dvab014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/20/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that affects the competence of academic performance and social wellness in children and adults. The causes of ADHD are unclear. Both genetic and environmental factors contribute to the development of ADHD. The behavioral impairments in ADHD are associated with epigenetic changes in genes that are important for neurodevelopment. Among environmental causes of ADHD, the neurotoxin methylmercury (MeHg) is associated with an increased risk for ADHD. Developing children are susceptible to neurotoxic effects of prenatal MeHg exposure. Human epidemiology studies have shown that prenatal MeHg exposure could invoke epigenetic changes in genes that are involved in ADHD. In addition, the pathogenesis of ADHD involves dopaminergic system, which is a target of developmental MeHg exposure. MeHg-induced alterations in the dopaminergic system have a profound impact on behavioral functions in adults. As a trace level of MeHg (around nM) can induce long-lasting behavioral alterations, potential mechanisms of MeHg-induced functional changes in the dopaminergic system may involve epigenetic mechanisms. Here, we review the relevant evidence on developmental MeHg exposures and the risk for ADHD. We also point out research gaps in understanding environmental causes of ADHD.
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Affiliation(s)
- Tao Ke
- **Correspondence address. Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer Building, Room 209, Bronx, NY 10461, USA. Tel: +1 718 430 4047; Fax: +1 718 430 8922; E-mail:
| | - Alexey A Tinkov
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow 119435, Russia
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl 150003, Russia
| | - Antoly V Skalny
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow 119435, Russia
- Laboratory of Medical Elementology, K.G. Razumovsky Moscow State University of Technologies and Management, Moscow 109004, Russia
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA
| | - Joao B T Rocha
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, Mexico
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer Building, Room 209, Bronx, NY 10461, USA
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12
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Delivery Mode and Child Development at 20 Months of Age and 7 Years of Age in the Republic of Seychelles. Matern Child Health J 2021; 25:1930-1938. [PMID: 34609706 DOI: 10.1007/s10995-021-03239-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To determine if cesarean delivery is adversely associated with child neurodevelopment as measured at 20 months and 7 years. METHODS In a prospective cohort study (n = 1328) in the Republic of Seychelles, we examined the association between mode of delivery and 22 measures of child neurodevelopment spanning multiple domains: cognition, executive and psychomotor function, language development, behavior, scholastic achievement, and social communication. Using multivariable linear regression, we evaluated the relationship between delivery mode (Cesarean/vaginal delivery) and each developmental outcome, while controlling for relevant covariates including child sex and age, maternal age, maternal IQ, whether both parents lived with the child, and Hollingshead socioeconomic status. RESULTS At 20 months, children born via cesarean delivery had slightly higher scores (β = 0.11, 95% confidence interval: 0.00, 0.21) on the Infant Behavior Questionnaire-Revised Positive Affectivity/Surgency subtest, a measure of infant temperament, as compared to vaginal delivery. Delivery mode was not associated with any of the 7-year developmental outcomes. CONCLUSIONS FOR PRACTICE Our study does not support the notion that cesarean delivery is associated with child neurodevelopmental outcomes.
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13
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Mendes VA, de Carvalho DP, de Almeida R, do N Recktenvald MCN, Pedrosa OP, de Sousa-Filho IF, Dórea JG, Bastos WR. Mercury in blood, hair, and feces from subsistence fish-eating riverines of the Madeira River Basin (Western Amazon). J Trace Elem Med Biol 2021; 67:126773. [PMID: 33993005 DOI: 10.1016/j.jtemb.2021.126773] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/04/2021] [Accepted: 05/04/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND The Madeira River (Amazon Basin) has been impacted by activities related to artisanal and small-scale gold mining (ASGM), deforestation and burning (for timber, agriculture, and hydroelectric dam projects). All these activities contribute to environmental mercury (Hg) release and cycling into the Amazon ecosystem and thus to changing lifestyles. METHOD We assessed exposure to total and MeHg in two small riverine communities of the Madeira River (Amazon): Lago Puruzinho (LP, n = 26 families) and São Sebastião do Tapurú (SST, n = 31 families). Samples of human hair (n = 137), blood (n = 39), and feces (n = 41) were collected from adults and children (0-15 years of age). RESULTS In women of childbearing age from LP village, the mean blood total-Hg (THg) (45.54 ± 24.76 μg.L-1) and MeHg (10.79 ± 4.36 μg.L-1) concentrations were significantly (p = 0.0024; p < 0.0001, respectively) higher than in women from SST village (THg: 25.32 ± 16.75 μg.L-1; MeHg: 2.32 ± 1.56 μg.L-1) village; the trend in hair-Hg persisted but was statistically significant (p < 0.0145) only for THg (LP, 11.34 ± 5.03 μg. g-1; SST, 7.97 ± 3.51 μg. g-1). In women, the median hair:blood ratio of total Hg was 269. In children, the mean hair THg concentrations were 6.07 ± 3.60 μg. g-1 and 6.47 ± 4.16 μg. g-1 in LP and SST; thus, not significantly different (p = 0.8006). There was a significant association (p < 0.001) between hair-Hg concentrations of mothers and their respective children. The excretion of Hg in feces of women (0.52 μg. g-1 dw) was not significantly different from children (0.49 μg. g-1 dw). The only statistically significant correlation between Hg in feces and in hair was found in children, (n = 16, rs = 0.38, p = 0.005). Significant relationship was seen between the levels of THg in blood and hair of women from LP and SST. Based on hair-Hg concentrations, fish consumption rate ranged from 94.5 to 212.3 g.day-1. CONCLUSION Women and children excrete THg in feces in comparable concentrations. However, the mean fish consumption rate and blood MeHg are higher in the most remote villagers. Mother`s hair-Hg concentration is a good predictor of children's hair-Hg.
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Affiliation(s)
- Vanessa A Mendes
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil; Departamento de Enfermagem, Fundação Universidade Federal de Rondônia, Brazil
| | | | - Ronaldo de Almeida
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil; Departamento Acadêmico de Ciências Sociais e Ambientais, Fundação Universidade Federal de Rondônia, Guajará-Mirim, Brazil
| | | | - Olakson P Pedrosa
- Departamento de Educação Física, Instituto Federal do Estado de Rondônia, Porto Velho, Brazil
| | - Izidro F de Sousa-Filho
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil
| | - José G Dórea
- Faculdade de Ciências da Saúde, Universidade de Brasília, Brazil
| | - Wanderley R Bastos
- Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil.
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14
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Chiu K, Warner G, Nowak RA, Flaws JA, Mei W. The Impact of Environmental Chemicals on the Gut Microbiome. Toxicol Sci 2021; 176:253-284. [PMID: 32392306 DOI: 10.1093/toxsci/kfaa065] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Since the surge of microbiome research in the last decade, many studies have provided insight into the causes and consequences of changes in the gut microbiota. Among the multiple factors involved in regulating the microbiome, exogenous factors such as diet and environmental chemicals have been shown to alter the gut microbiome significantly. Although diet substantially contributes to changes in the gut microbiome, environmental chemicals are major contaminants in our food and are often overlooked. Herein, we summarize the current knowledge on major classes of environmental chemicals (bisphenols, phthalates, persistent organic pollutants, heavy metals, and pesticides) and their impact on the gut microbiome, which includes alterations in microbial composition, gene expression, function, and health effects in the host. We then discuss health-related implications of gut microbial changes, which include changes in metabolism, immunity, and neurological function.
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Affiliation(s)
- Karen Chiu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802.,Division of Nutritional Sciences, College of Agricultural, Consumer, and Environmental Sciences
| | - Genoa Warner
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
| | - Romana A Nowak
- Carl R. Woese Institute for Genomic Biology.,Department of Animal Sciences, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Jodi A Flaws
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802.,Division of Nutritional Sciences, College of Agricultural, Consumer, and Environmental Sciences.,Carl R. Woese Institute for Genomic Biology
| | - Wenyan Mei
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802.,Carl R. Woese Institute for Genomic Biology
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Rothenberg SE, Sweitzer DN, Rackerby BR, Couch CE, Cohen LA, Broughton HM, Steingass SM, Beechler BR. Fecal Methylmercury Correlates With Gut Microbiota Taxa in Pacific Walruses ( Odobenus rosmarus divergens). Front Microbiol 2021; 12:648685. [PMID: 34177830 PMCID: PMC8220164 DOI: 10.3389/fmicb.2021.648685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/30/2021] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVES Methylmercury metabolism was investigated in Pacific walruses (Odobenus rosmarus divergens) from St. Lawrence Island, Alaska, United States. METHODS Total mercury and methylmercury concentrations were measured in fecal samples and paired colon samples (n = 16 walruses). Gut microbiota composition and diversity were determined using 16S rRNA gene sequencing. Associations between fecal and colon mercury and the 24 most prevalent gut microbiota taxa were investigated using linear models. RESULTS In fecal samples, the median values for total mercury, methylmercury, and %methylmercury (of total mercury) were 200 ng/g, 4.7 ng/g, and 2.5%, respectively, while in colon samples, the median values for the same parameters were 28 ng/g, 7.8 ng/g, and 26%, respectively. In fecal samples, methylmercury was negatively correlated with one Bacteroides genus, while members of the Oscillospirales order were positively correlated with both methylmercury and %methylmercury (of total mercury). In colon samples, %methylmercury (of total mercury) was negatively correlated with members of two genera, Romboutsia and Paeniclostridium. CONCLUSIONS Median %methylmercury (of total mercury) was 10 times higher in the colon compared to the fecal samples, suggesting that methylmercury was able to pass through the colon into systemic circulation. Fecal total mercury and/or methylmercury concentrations in walruses were comparable to some human studies despite differences in seafood consumption rates, suggesting that walruses excreted less mercury. There are no members (at this time) of the Oscillospirales order which are known to contain the genes to methylate mercury, suggesting the source of methylmercury in the gut was from diet and not in vivo methylation.
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Affiliation(s)
- Sarah E. Rothenberg
- College of Public Health and Human Sciences, Oregon State University, Corvallis, OR, United States
| | - Danielle N. Sweitzer
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
| | - Bryna R. Rackerby
- Department of Food Science and Technology, College of Agricultural Sciences, Oregon State University, Corvallis, OR, United States
| | - Claire E. Couch
- Department of Fisheries, Wildlife, and Conservation Sciences, College of Agricultural Sciences, Oregon State University, Corvallis, OR, United States
| | - Lesley A. Cohen
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
| | - Heather M. Broughton
- Department of Biology, Oregon State University-Cascades, Bend, OR, United States
| | - Sheanna M. Steingass
- Department of Fisheries, Wildlife, and Conservation Sciences, Marine Mammal Institute, Oregon State University, Corvallis, OR, United States
| | - Brianna R. Beechler
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
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16
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Gochfeld M, Burger J. Mercury interactions with selenium and sulfur and the relevance of the Se:Hg molar ratio to fish consumption advice. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:18407-18420. [PMID: 33507504 PMCID: PMC8026698 DOI: 10.1007/s11356-021-12361-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/02/2021] [Indexed: 05/20/2023]
Abstract
Eating fish is often recommended as part of a healthful diet. However, fish, particularly large predatory fish, can contain significant levels of the highly toxic methylmercury (MeHg). Ocean fish in general also contain high levels of selenium (Se), which is reported to confer protection against toxicity of various metals including mercury (Hg). Se and Hg have a high mutual binding affinity, and each can reduce the toxicity of the other. This is an evolving area of extensive research and controversy with variable results in the animal and epidemiologic literature. MeHg is toxic to many organ systems through high affinity for -SH (thiol) ligands on enzymes and microtubules. Hg toxicity also causes oxidative damage particularly to neurons in the brain. Hg is a potent and apparently irreversible inhibitor of the selenoenzymes, glutathione peroxidases (GPX), and thioredoxin reductases (TXNRD) that are important antioxidants, each with a selenocysteine (SeCys) at the active site. Hg binding to the SeCys inhibits these enzymes, accounting in part for the oxidative damage that is an important manifestation of Hg toxicity, particularly if there is not a pool of excess Se to synthesize new enzymes. A molar excess of Se reflected in an Se:Hg molar ratio > 1 is often invoked as evidence that the Hg content can be discounted. Some recent papers now suggest that if the Se:Hg molar ratio exceeds 1:1, the fish is safe and the mercury concentration can be ignored. Such papers suggested that the molar ratio rather than the Hg concentration should be emphasized in fish advisories. This paper examines some of the limitations of current understanding of the Se:Hg molar ratio in guiding fish consumption advice; Se is certainly an important part of the Hg toxicity story, but it is not the whole story. We examine how Hg toxicity relates also to thiol binding. We suggest that a 1:1 molar ratio cannot be relied on because not all of the Se in fish or in the fish eater is available to interact with Hg. Moreover, in some fish, Se levels are sufficiently high to warrant concern about Se toxicity.
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Affiliation(s)
- Michael Gochfeld
- Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, NJ, USA.
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Joanna Burger
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA
- Division of Life Science, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854, USA
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17
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Pope Q, Rand MD. Variation in Methylmercury Metabolism and Elimination in Humans: Physiological Pharmacokinetic Modeling Highlights the Role of Gut Biotransformation, Skeletal Muscle, and Hair. Toxicol Sci 2021; 180:26-37. [PMID: 33481013 PMCID: PMC7916735 DOI: 10.1093/toxsci/kfaa192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The biological half-life (t1/2) of methylmercury (MeHg) shows considerable individual variability (t1/2 < 30 to > 120 days), highlighting the importance of mechanisms controlling MeHg metabolism and elimination. Building on a prior physiologically based pharmacokinetic (PBPK) model, we elucidate parameters that have the greatest influence on variability of MeHg t1/2 in the human body. Employing a dataset of parameters for mean organ volumes and blood flow rates appropriate for man and woman (25-35 years) and child (4 - 6 years), we demonstrate model fitness by simulating data from our prior controlled study of MeHg elimination in people. Model predictions give MeHg t1/2 of 46.9, 38.9, and 31.5 days and steady-state blood MeHg of 2.6, 2.6, and 2.3 µg/l in man, woman, and child, respectively, subsequent to a weekly dose of 0.7 µg/kg body weight. The major routes of elimination are biotransformation to inorganic Hg in the gut lumen (73% in adults, 61% in child) and loss of MeHg via excretion within growing hair (13% in adults, 24% in child). Local and global sensitivity analyses of model parameters reveal that variation in biotransformation rate in the gut lumen, and rates of transport between gut lumen and gut tissue, have the greatest influence on MeHg t1/2. Volume and partition coefficients for skeletal muscle (SM) and gut tissue also show significant sensitivity affecting model output of MeHg t1/2. Our results emphasize the role of gut microbiota in MeHg biotransformation, transport kinetics at the level of the gut, and SM mass as moderators of MeHg kinetics in the human body.
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Affiliation(s)
- Quintin Pope
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Matthew D Rand
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
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18
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Chiu K, Warner G, Nowak RA, Flaws JA, Mei W. The Impact of Environmental Chemicals on the Gut Microbiome. Toxicol Sci 2020. [PMID: 32392306 DOI: 10.1093/toxsci/kfaa1065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
Since the surge of microbiome research in the last decade, many studies have provided insight into the causes and consequences of changes in the gut microbiota. Among the multiple factors involved in regulating the microbiome, exogenous factors such as diet and environmental chemicals have been shown to alter the gut microbiome significantly. Although diet substantially contributes to changes in the gut microbiome, environmental chemicals are major contaminants in our food and are often overlooked. Herein, we summarize the current knowledge on major classes of environmental chemicals (bisphenols, phthalates, persistent organic pollutants, heavy metals, and pesticides) and their impact on the gut microbiome, which includes alterations in microbial composition, gene expression, function, and health effects in the host. We then discuss health-related implications of gut microbial changes, which include changes in metabolism, immunity, and neurological function.
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Affiliation(s)
- Karen Chiu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
- Division of Nutritional Sciences, College of Agricultural, Consumer, and Environmental Sciences
| | - Genoa Warner
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
| | - Romana A Nowak
- Carl R. Woese Institute for Genomic Biology
- Department of Animal Sciences, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Jodi A Flaws
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
- Division of Nutritional Sciences, College of Agricultural, Consumer, and Environmental Sciences
- Carl R. Woese Institute for Genomic Biology
| | - Wenyan Mei
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
- Carl R. Woese Institute for Genomic Biology
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19
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Mehri A. Trace Elements in Human Nutrition (II) - An Update. Int J Prev Med 2020; 11:2. [PMID: 32042399 PMCID: PMC6993532 DOI: 10.4103/ijpvm.ijpvm_48_19] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 10/14/2019] [Indexed: 11/30/2022] Open
Abstract
The dietary requirement for an essential trace element is an intake level which meets a specified criterion for adequacy and thereby minimizes risk of nutrient deficiency or excess. Disturbances in trace element homeostasis may result in the development of pathologic states and diseases. This article is an update of a review article “Trace Elements in Human Nutrition-A Review” previously published in 2013. The previous review was updated to emphasis in detail the importance of known trace elements so far in humans’ physiology and nutrition and also to implement the detailed information for practical and effective management of trace elements’ status in clinical diagnosis and health care situations. Although various classifications for trace elements have been proposed and may be controversial, this review will use World Health Organization( WHO) classification as previously done. For this review a traditional integrated review format was chosen and many recent medical and scientific literatures for the new findings on bioavailability, functions, and state of excess/deficiency of trace elements were assessed. The results indicated that for the known essential elements, essentiality and toxicity are unrelated and toxicity is a matter of dose or exposure. Little is known about the essentiality of some of the probably essential elements. In regard to toxic heavy metals, a toxic element may nevertheless be essential. In addition, the early pathological manifestations of trace elements deficiency or excess are difficult to detect until more specific pathologically relevant indicators become available. Discoveries and many refinements in the development of new techniques and continual improvement in laboratory methods have enabled researchers to detect the early pathological consequences of deficiency or excess of trace elements. They all are promises to fulfill the gaps in the present and future research and clinical diagnosis of trace elements deficiencies or intoxications. However, further investigations are needed to complete the important gaps in our knowledge on trace elements, especially probably essential trace elements’ role in health and disease status.
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Affiliation(s)
- Aliasgharpour Mehri
- Department of Biochemistry, Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran
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20
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Rand MD, Caito SW. Variation in the biological half-life of methylmercury in humans: Methods, measurements and meaning. Biochim Biophys Acta Gen Subj 2019; 1863:129301. [PMID: 30742954 DOI: 10.1016/j.bbagen.2019.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/04/2019] [Accepted: 02/01/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Understanding methylmercury (MeHg) toxicity requires a complete understanding of its fundamental toxicokinetic and toxicodynamic characteristics in the human body. The biological half-life (t1/2) of MeHg is a kinetic property that directly influences the body burden of Hg that results from repeated exposures such as can occur with fish and seafood consumption. The t1/2 of MeHg in humans is approximately 50 days, equivalent to an elimination rate (kel) of 0.014 day-1. However, numerous studies report a wide range of half-life values (t1/2 < 30 to >120 days), demonstrating that significant variation in the biological process of MeHg elimination exists. This variation is a source of considerable uncertainty in deriving a meaningful reference dose for MeHg applicable to all individuals in a population. SCOPE OF REVIEW First, we summarize fundamentals of MeHg toxicokinetics, emphasizing the central role that biological half-life plays in MeHg dosimetry. We next present important considerations for how kinetic analyses are performed. We provide an example of how MeHg half-life variation directly influences the body burden and, in certain contexts, can result in MeHg levels exceeding the US EPA Reference Dose. We then survey existing studies that report MeHg half-life determinations in people. MAJOR CONCLUSIONS Recent advances in methods of determining MeHg kinetics in people have made individualized assessment of MeHg elimination rates more accurate and readily obtainable. GENERAL SIGNIFICANCE Characterization of MeHg half-life, particularly in vulnerable individuals, such as pregnant women and children, will diminish the remaining toxicokinetic uncertainty surrounding MeHg exposures and will better inform the risk assessment process.
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Affiliation(s)
- Matthew D Rand
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States.
| | - Samuel W Caito
- Husson University, School of Pharmacy, Bangor, ME 04401, United States
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21
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Trdin A, Falnoga I, Fajon V, Živković I, Snoj Tratnik J, Prpić I, Špirić Z, Horvat M. Mercury speciation in meconium and associated factors. ENVIRONMENTAL RESEARCH 2019; 179:108724. [PMID: 31627028 DOI: 10.1016/j.envres.2019.108724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/21/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Meconium is formed early in gestation and it is normally not excreted until after birth. Thus it may provide a longer and cumulative record of exposure to mercury (Hg). The present study aims to speciate Hg in meconium samples (N = 488) from Slovenian and Croatian new-borns prenatally exposed to low levels of methyl-Hg (MeHg) from maternal seafood intake and to Hg0 from maternal dental amalgam fillings. We had complete data of total Hg (THg) and MeHg in meconium and THg in maternal hair (MH), while THg and MeHg in maternal blood (MB) were available only for Croatian mothers. Personal data namely maternal seafood intake, age, pre-pregnancy BMI, parity, smoking, estimated gestational age at birth, sex, and birth weight were available for the majority of participants, except the number of dental amalgams which was in most cases missing for Croatian mothers. The median THg concentration in meconium was 11.1 (range: 0.41-375.2) ng/g and inorganic Hg (Hg(II)) presented 98.8% (range: 82%-100%, CV: 2%) of THg. We observed significant correlation between meconium and MH Hg levels, with the highest correlation between hair THg and meconium MeHg. Correlation analysis including MB (available only for Croatian population) showed a significant positive correlation between THg in meconium and THg in MB (Rs = 0.642). Additionally, MeHg from MB was correlated with MeHg in meconium (Rs = 0.898), while the correlation between Hg(II) in MB and meconium was positive, but not significant. Maternal seafood intake was significantly correlated with meconium MeHg (Rs = 0.498) and Hg(II) (Rs = 0.201). Multiple linear regression (performed on the Slovenian population, N = 143) confirmed a positive association between meconium MeHg and seafood intake. Furthermore, meconium Hg(II) was positively associated with the number of maternal dental amalgam fillings, but linear regression models did not confirm correlation between seafood intake and meconium Hg(II) levels. We assume that Hg0 released from maternal dental amalgam fillings and MeHg from seafood intake were both transported through the placental barrier and portioned between different foetal compartments including meconium. Weak correlation between maternal seafood intake and Hg(II) levels in meconium suggests that there is certain evidence of MeHg demethylation. However, because this correlation was not confirmed by the multiple regression, MeHg demethylation during prenatal life cannot be neither confirmed nor excluded. Further investigations at higher level of exposure are needed to confirm this observations. We can conclude that meconium is a suitable biomarker for MeHg and Hg0 exposure during pregnancy. However, comparability of the results reported in meconium in different studies is hindered by a lack of standardized sampling protocols, storage, and analysis.
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Affiliation(s)
- Ajda Trdin
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Ingrid Falnoga
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Vesna Fajon
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Janja Snoj Tratnik
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Igor Prpić
- Department of Paediatrics, University Hospital Centre Rijeka, Rijeka, Croatia
| | | | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia.
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22
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Subhavana KL, Qureshi A, Roy A. Mercury levels in human hair in South India: baseline, artisanal goldsmiths and coal-fired power plants. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2019; 29:697-705. [PMID: 30631141 DOI: 10.1038/s41370-018-0107-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 11/06/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
India is a major emitter of mercury to the environment, mainly due to emissions from coal-fired power plants. Consumption of fish and rice, two important pathways for human exposure to mercury, is particularly high in South India. Here, we report concentrations of total mercury in hair (THghair) in 668 participants from South India. Three cities were covered: (i) a city on the east coast with four active coal-fired thermal power plants (Nellore), (ii) a city on the west coast with no major mercury source (Vasco da Gama), and (iii) a metropolitan city in the interior with no major mercury source (Hyderabad). Geometric mean of THghair of the entire study population is 0.14 µg/g (95% confidence interval, CI: 0.13-0.15 µg/g). Significant predictor variables are age, fish consumption, and occupations such as dental studies, subsistence fishing, and artisanal goldsmithing (which is different from artisanal scale gold mining). Our results support the hypothesis that people living in a city with active coal-fired power plants may have higher THghair than those in cities with no major mercury source.
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Affiliation(s)
- K L Subhavana
- Indian Institute of Technology (IIT) Hyderabad, Kandi, TS, 502285, India
| | - Asif Qureshi
- Indian Institute of Technology (IIT) Hyderabad, Kandi, TS, 502285, India.
| | - Arpita Roy
- Indian Institute of Technology (IIT) Hyderabad, Kandi, TS, 502285, India
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23
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Reardon AJF, Karathra J, Ribbenstedt A, Benskin JP, MacDonald AM, Kinniburgh DW, Hamilton TJ, Fouad K, Martin JW. Neurodevelopmental and Metabolomic Responses from Prenatal Coexposure to Perfluorooctanesulfonate (PFOS) and Methylmercury (MeHg) in Sprague-Dawley Rats. Chem Res Toxicol 2019; 32:1656-1669. [PMID: 31340646 DOI: 10.1021/acs.chemrestox.9b00192] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Methylmercury (MeHg) and perfluorooctanesulfonate (PFOS) are major contaminants of human blood that are both common in dietary fish, thereby raising questions about their combined impact on human development. Here, pregnant Sprague-Dawley rats ingested a daily dose, from gestational day 1 through to weaning, of either 1 mg/kg bw PFOS (PFOS-only), 1 mg/kg MeHg (MeHg-only), a mixture of 0.1 mg/kg PFOS and 1 mg/kg MeHg (Low-Mix), or of 1 mg/kg of PFOS and 1 mg/kg MeHg (High-Mix). Newborns were monitored for physical milestones and reflexive developmental responses, and in juveniles the spontaneous activity, anxiety, memory, and cognition were assessed. Targeted metabolomics of 199 analytes was applied to sectioned brain regions of juvenile offspring. Newborns in the High-Mix group had decreased weight gain as well as delayed reflexes and innate behavioral responses compared to controls and individual chemical groups indicating a toxicological interaction on early development. In juveniles, cumulative mixture effects increased in a dose-dependent manner in tests of anxiety-like behavior. However, other developmental test results suggested antagonism, as PFOS-only and MeHg-only juveniles had increased hyperactivity and thigmotaxic behavior, respectively, but fewer effects in Low-Mix and High-Mix groups. Consistent with these behavioral observations, a pattern of antagonism was also observed in neurochemicals measured in rat cortex, as PFOS-only and MeHg-only juveniles had altered concentrations of metabolites (e.g., lipids, amino acids, and biogenic amines), while no changes were evident in the combined exposures. The cortical metabolites altered in PFOS-only and MeHg-only exposed groups are involved in inhibitory and excitatory neurotransmission. These proof-of-principle findings at relatively high doses indicate the potential for toxicological interaction between PFOS and MeHg, with developmental-stage specific effects. Future mixture studies at lower doses are warranted, and prospective human birth cohorts should consider possible confounding effects from PFOS and mercury exposure on neurodevelopment.
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Affiliation(s)
- Anthony J F Reardon
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Jacqueline Karathra
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Anton Ribbenstedt
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Jonathan P Benskin
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Amy M MacDonald
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - David W Kinniburgh
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - Trevor J Hamilton
- Department of Psychology , MacEwan University , Edmonton , Alberta T5J 4S2 , Canada
| | - Karim Fouad
- Department of Physical Therapy , University of Alberta , Edmonton , Alberta T6G 2G4 , Canada
| | - Jonathan W Martin
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada.,Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
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24
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Bjørklund G, Chirumbolo S, Dadar M, Pivina L, Lindh U, Butnariu M, Aaseth J. Mercury exposure and its effects on fertility and pregnancy outcome. Basic Clin Pharmacol Toxicol 2019; 125:317-327. [PMID: 31136080 DOI: 10.1111/bcpt.13264] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 05/22/2019] [Indexed: 12/11/2022]
Abstract
Mercury (Hg), a highly toxic environmental pollutant, shows harmfulness which still represents a big concern for human health, including hazards to fertility and pregnancy outcome. Research has shown that Hg could induce impairments in the reproductive function, cellular deformation of the Leydig cells and the seminiferous tubules, and testicular degeneration as well as abnormal menstrual cycles. Some studies investigated spontaneous abortion and complicated fertility outcome due to occupational Hg exposure. Moreover, there is a relation between inhaled Hg vapour and reproductive outcome. This MiniReview evaluates the hypothesis that exposure to Hg may increase the risk of reduced fertility, spontaneous abortion and congenital deficits or abnormalities.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Mo i Rana, Norway
| | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,CONEM Scientific Secretary, Verona, Italy
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Lyudmila Pivina
- Semey Medical University, Semey, Kazakhstan.,CONEM Kazakhstan Environmental Health and Safety Research Group, Semey Medical University, Semey, Kazakhstan
| | - Ulf Lindh
- Biology Education Centre, Uppsala University, Uppsala, Sweden
| | - Monica Butnariu
- Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara, Timisoara, Romania.,CONEM Romania Biotechnology and Environmental Sciences Group, Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara, Timisoara, Romania
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway.,Inland Norway University of Applied Sciences, Elverum, Norway
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25
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Rothenberg SE, Wagner CL, Hamidi B, Alekseyenko AV, Andrea Azcarate-Peril M. Longitudinal changes during pregnancy in gut microbiota and methylmercury biomarkers, and reversal of microbe-exposure correlations. ENVIRONMENTAL RESEARCH 2019; 172:700-712. [PMID: 30903970 PMCID: PMC6675619 DOI: 10.1016/j.envres.2019.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/06/2019] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
OBJECTIVE Gut microorganisms contribute to the metabolism of environmental toxicants, including methylmercury (MeHg). Our main objective was to investigate whether associations between biomarkers for prenatal MeHg exposure and maternal gut microbiota differed between early and late gestation. METHODS Maternal blood and stool samples were collected during early (8.3-17 weeks, n=28) and late (27-36 weeks, n=24) gestation. Total mercury and MeHg concentrations were quantified in biomarkers, and inorganic mercury was estimated by subtraction. The diversity and structure of the gut microbiota were investigated using 16S rRNA gene profiling (n = 52). Biomarkers were dichotomized, and diversity patterns were compared between high/low mercury concentrations. Spearman's correlation was used to assess bivariate associations between MeHg biomarkers (stool, blood, and meconium), and 23 gut microbial taxa (genus or family level, >1% average relative abundance). RESULTS Within-person and between-person diversity patterns in gut microbiota differed between early/late gestation. The overall composition of the microbiome differed between high/low MeHg concentrations (in blood and stool) during early gestation, but not late gestation. Ten (of 23) taxa were significantly correlated with MeHg biomarkers (increasing or decreasing); however, associations differed, depending on whether the sample was collected during early or late gestation. A total of 43% of associations (69/161) reversed the direction of correlation between early/late gestation. CONCLUSIONS The time point at which a maternal fecal sample is collected may yield different associations between gut microorganisms and MeHg biomarkers, which may be due in part to remodeling of maternal microbiota during pregnancy. Our results suggest the effectiveness of dietary interventions to reduce prenatal MeHg exposure may differ between early and late gestation.
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Affiliation(s)
- Sarah E Rothenberg
- School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA.
| | - Carol L Wagner
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA
| | - Bashir Hamidi
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Alexander V Alekseyenko
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - M Andrea Azcarate-Peril
- Division of Gastroenterology and Hepatology and Microbiome Core Facility, University of North Carolina, Chapel Hill, NC, USA
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26
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Konkel L. What Is Your Gut Telling You? Exploring the Role of the Microbiome in Gut-Brain Signaling. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:062001. [PMID: 29883071 PMCID: PMC6108581 DOI: 10.1289/ehp3127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/21/2017] [Indexed: 06/08/2023]
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27
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Guo G, Yumvihoze E, Poulain AJ, Man Chan H. Monomethylmercury degradation by the human gut microbiota is stimulated by protein amendments. J Toxicol Sci 2018; 43:717-725. [DOI: 10.2131/jts.43.717] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Galen Guo
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Canada K1N 9B4
| | - Emmanuel Yumvihoze
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Canada K1N 9B4
| | - Alexandre J. Poulain
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Canada K1N 9B4
| | - Hing Man Chan
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Canada K1N 9B4
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