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Mphephu MM, Olaokun OO, Mavimbela C, Hofmeyer G, Mwale M, Mkolo NM. Metabolomics approach for predicting stomach and colon contents in dead Arctocephalus pusillus pusillus, Arctocephalus tropicalis, Lobodon carcinophaga and Ommatophoca rossii from sub-Antarctic region. PLoS One 2024; 19:e0300319. [PMID: 38557648 PMCID: PMC10984408 DOI: 10.1371/journal.pone.0300319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 02/27/2024] [Indexed: 04/04/2024] Open
Abstract
The dietary habits of seals play a pivotal role in shaping management and administration policies, especially in regions with potential interactions with fisheries. Previous studies have utilized various methods, including traditional approaches, to predict seal diets by retrieving indigestible prey parts, such as calcified structures, from intestines, feces, and stomach contents. Additionally, methods evaluating nitrogen and stable isotopes of carbon have been employed. The metabolomics approach, capable of quantifying small-scale molecules in biofluids, holds promise for specifying dietary exposures and estimating disease risk. This study aimed to assess the diet composition of five seal species-Arctocephalus pusillus pusillus, Lobodon carcinophaga, Ommatophoca rossii, and Arctocephalus tropicalis 1 and 2-by analyzing stomach and colon contents collected from stranded dead seals at various locations. Metabolite concentrations in the seal stomach and colon contents were determined using Nuclear Magnetic Resonance Spectroscopy. Among the colon and stomach contents, 29 known and 8 unknown metabolites were identified. Four metabolites (alanine, fumarate, lactate, and proline) from stomach contents and one metabolite (alanine) from colon contents showed no significant differences between seal species (p>0.05). This suggests that traces of these metabolites in the stomach and colon contents may be produced by the seals' gut microbiome or derived from other animals, possibly indicating reliance on fish caught at sea. Despite this insight, the cause of death for stranded seals remains unclear. The study highlights the need for specific and reliable biomarkers to precisely indicate dietary exposures across seal populations. Additionally, there is a call for the development of relevant metabolite and disease interaction networks to explore disease-related metabolites in seals. Ultimately, the metabolomic method employed in this study reveals potential metabolites in the stomach and colon contents of these seal species.
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Affiliation(s)
- Mukhethwa Micheal Mphephu
- Department of Biology, School of Science and Technology, Sefako Makgatho Health Science University, Ga-Rankuwa, Pretoria, South Africa
| | - Oyinlola Oluwunmi Olaokun
- Department of Biology, School of Science and Technology, Sefako Makgatho Health Science University, Ga-Rankuwa, Pretoria, South Africa
| | - Caswell Mavimbela
- Department of Biology, School of Science and Technology, Sefako Makgatho Health Science University, Ga-Rankuwa, Pretoria, South Africa
| | - Greg Hofmeyer
- Port Elizabeth Museum at Bayworld, Humewood, Port Elizabeth, South Africa
| | - Monica Mwale
- South African National Biodiversity Institute (SANBI), National Zoological Garden, Pretoria, South Africa
| | - Nqobile Monate Mkolo
- Department of Biology, School of Science and Technology, Sefako Makgatho Health Science University, Ga-Rankuwa, Pretoria, South Africa
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Boyi JO, Sonne C, Dietz R, Rigét F, Siebert U, Lehnert K. Gene expression and trace elements in Greenlandic ringed seals (Pusa hispida). ENVIRONMENTAL RESEARCH 2024; 244:117839. [PMID: 38081340 DOI: 10.1016/j.envres.2023.117839] [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: 10/13/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Marine top predators such as ringed seals biomagnify environmental contaminants; and with the increasing human activities in the Arctic, ringed seals are exposed to biologically significant concentrations of trace elements resulting in reproductive impairment, immunosuppression, and neurological damages. Little is known about the molecular effects of heavy metals on these vulnerable apex predators suffering from a rapidly changing Arctic with significant loss of sea-ice. In the present study, concentrations of cadmium (Cd), mercury (Hg) and selenium (Se) were measured in liver of sixteen Greenlandic ringed seals (nine adults and seven subadults) together with molecular biomarkers involved in bio-transformation, oxidative stress, endocrine disruption and immune activity in blood and blubber. The concentrations of trace elements increased in the following order: Hg > Se > Cd with levels of mercury and selenium being highest in adults. Aryl hydrocarbon receptor nuclear translocator (ARNT), peroxisome proliferator activated receptor alpha (PPARα, estrogen receptor alpha (ESR1), thyroid hormone receptor alpha (TRα) and interleukin - 2 (IL-2) mRNA transcript levels were highest in blubber, while heat shock protein 70 (HSP70) and interleukin - 10 (IL-10) were significantly higher in blood. There were no significant correlations between the concentrations of trace elements and mRNA transcript levels suggesting that stressors other than the trace elements investigated are responsible for the changes in gene expression levels. Since Hg seems to increase in Greenlandic ringed seals, there is a need to re-enforce health monitoring of this ringed seal population.
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Affiliation(s)
- Joy Ometere Boyi
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.
| | - Christian Sonne
- Department of Ecoscience, Aarhus University, Roskilde, Denmark.
| | - Rune Dietz
- Department of Ecoscience, Aarhus University, Roskilde, Denmark.
| | - Frank Rigét
- Department of Ecoscience, Aarhus University, Roskilde, Denmark.
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.
| | - Kristina Lehnert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.
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Linsky JMJ, Dunlop RA, McMichael LA. A novel RT-qPCR health assay reveals differential expression of stress and immunoregulatory genes between the seasonal migrations of humpback whales (Megaptera novaeangliae). Mol Ecol 2024; 33:e17209. [PMID: 38018561 DOI: 10.1111/mec.17209] [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: 05/26/2023] [Revised: 10/24/2023] [Accepted: 11/03/2023] [Indexed: 11/30/2023]
Abstract
Health information is essential for the conservation management of whale species. However, assessing the health of free-ranging whales is challenging as samples are primarily limited to skin and blubber tissue. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) offers a method to measure health from blubber RNA, providing insights into energetic status, stress and immune activity. To identify changes in health, natural differences in baseline gene expression linked to an individual's sex, reproductive status and life-history stage must first be quantified. This study aimed to establish baseline gene expression indices of health in migrating humpback whales (Megaptera novaeangliae). To do this, we developed an assay to quantify seven health-related gene transcripts (Leptin, Leptin Receptor, Adiponectin, Aryl Hydrocarbon Receptor, Tumour Necrosis Factor-α, Interleukin-6, Heat Shock Protein-70) and used Bayesian mixed effect models to assess differential baseline expression based on sex, lactation status and migration stage (northbound to and southbound from the annual breeding grounds). Results showed no significant contribution of sex to differential baseline expression. However, lactating individuals exhibited downregulated AhR and HSP-70 compared to non-lactating conspecifics. Additionally, southbound individuals demonstrated significantly upregulated HSP-70 and downregulated TNF-alpha, suggesting a relationship between these inflammation-linked transcripts and migratory fasting. Our results suggest that baseline differences due to migratory stage and lactation status should be considered in health applications of this assay. Future monitoring efforts can use our baseline measurements to better understand how gene expression is tied to population-level impacts, such as reduced prey availability or migratory stressors.
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Affiliation(s)
- Jacob M J Linsky
- School of the Environment, The University of Queensland, St Lucia, Queensland, Australia
| | - Rebecca A Dunlop
- School of the Environment, The University of Queensland, St Lucia, Queensland, Australia
| | - Lee A McMichael
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
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Charapata P, Clark CT, Miller N, Kienle SS, Costa DP, Goebel ME, Gunn H, Sperou ES, Kanatous SB, Crocker DE, Borras-Chavez R, Trumble SJ. Whiskers provide time-series of toxic and essential trace elements, Se:Hg molar ratios, and stable isotope values of an apex Antarctic predator, the leopard seal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158651. [PMID: 36096211 DOI: 10.1016/j.scitotenv.2022.158651] [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: 05/23/2022] [Revised: 08/11/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
In an era of rapid environmental change and increasing human presence, researchers need efficient tools for tracking contaminants to monitor the health of Antarctic flora and fauna. Here, we examined the utility of leopard seal whiskers as a biomonitoring tool that reconstructs time-series of significant ecological and physiological biomarkers. Leopard seals (Hydrurga leptonyx) are a sentinel species in the Western Antarctic Peninsula due to their apex predator status and top-down effects on several Antarctic species. However, there are few data on their contaminant loads. We analyzed leopard seal whiskers (n = 18 individuals, n = 981 segments) collected during 2018-2019 field seasons to acquire longitudinal profiles of non-essential (Hg, Pb, and Cd) and essential (Se, Cu, and Zn) trace elements, stable isotope (ẟ15N and ẟ13C) values and to assess Hg risk with Se:Hg molar ratios. Whiskers provided between 46 and 286 cumulative days of growth with a mean ~ 125 days per whisker (n = 18). Adult whiskers showed variability in non-essential trace elements over time that could partly be explained by changes in diet. Whisker Hg levels were insufficient (<20 ppm) to consider most seals being at "high" risk for Hg toxicity. Nevertheless, maximum Hg concentrations observed in this study were greater than that of leopard seal hair measured two decades ago. However, variation in the Se:Hg molar ratios over time suggest that Se may detoxify Hg burden in leopard seals. Overall, we provide evidence that the analysis of leopard seal whiskers allows for the reconstruction of time-series ecological and physiological data and can be valuable for opportunistically monitoring the health of the leopard seal population and their Antarctic ecosystem during climate change.
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Affiliation(s)
- Patrick Charapata
- Baylor University, Biology Department, Waco, TX, United States of America.
| | - Casey T Clark
- Washington Department of Fish and Wildlife, Marine Mammal Research Division, Olympia, WA, United States of America
| | - Nathan Miller
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX, United States of America
| | - Sarah S Kienle
- Baylor University, Biology Department, Waco, TX, United States of America
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, The University of California at Santa Cruz, Santa Cruz, CA, United States of America
| | - Michael E Goebel
- Department of Ecology and Evolutionary Biology, The University of California at Santa Cruz, Santa Cruz, CA, United States of America; Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA) Fisheries, La Jolla, CA, United States of America
| | - Heather Gunn
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX, United States of America; Department of Earth and Environmental Sciences, Syracuse University, Syracuse, NY, United States of America
| | - Emily S Sperou
- Baylor University, Biology Department, Waco, TX, United States of America
| | - Shane B Kanatous
- Department of Biology, Colorado State University, Fort Collins, CO, United States of America
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, United States of America
| | - Renato Borras-Chavez
- Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Stephen J Trumble
- Baylor University, Biology Department, Waco, TX, United States of America
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Ometere Boyi J, Stokholm I, Hillmann M, Søndergaard J, Persson S, de Wit CA, Siebert U, Kristina L. Relationships between gene transcription and contaminant concentrations in Baltic ringed seals: A comparison between tissue matrices. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 242:106035. [PMID: 34856463 DOI: 10.1016/j.aquatox.2021.106035] [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: 06/22/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Ringed seals (Pusa hispida) are slowly recovering in the eastern and northern parts of the Baltic Sea after years of hunting pressure and contaminant exposure. Still, consequences of anthropogenic activities such as contaminant exposure and increasing temperatures are stressors that continue to have deleterious effects on their habitat and health. Transcription profiles of seven health-related genes involved in xenobiotic metabolism, endocrine disruption and stress were evaluated in blood, blubber, and liver of Baltic ringed seals in a multi-tissue approach. Selected persistent organic pollutants and total mercury concentrations were measured in blubber and liver, and muscle and liver of these animals, respectively. Concentrations of contaminants varied across tissues on a lipid weight basis but not with sex. mRNA transcript levels for all seven target genes did not vary between sexes or age classes. Transcript levels of thyroid hormone receptor alpha (TRα), retinoic acid receptor alpha (RARα) and heat shock protein 70 (HSP70) correlated with levels of persistent organic pollutants. TRα transcript levels also correlated positively with mercury concentrations in the liver. Of the three tissues assessed in this multi-tissue approach, blubber showed highest transcription levels of aryl hydrocarbon receptor nuclear translocator (ARNT), thyroid stimulating hormone receptor beta (TSHβ), oestrogen receptor alpha (ESR1) and peroxisome proliferator activated receptor alpha (PPARα). The wide range of genes expressed highlights the value of minimally invasive sampling (e.g. biopsies) for assessing health endpoints in free-ranging marine wildlife and the importance of identifying optimal matrices for targeted gene expression studies. This gene transcript profile study has provided baseline information on transcript levels of biomarkers for early on-set health effects in ringed seals and will be a useful guide to assess the impacts of environmental change in Baltic pinnipeds for conservation and management.
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Affiliation(s)
- Joy Ometere Boyi
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Buesum D-25761, Germany
| | - Iben Stokholm
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Buesum D-25761, Germany
| | - Miriam Hillmann
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Buesum D-25761, Germany
| | - Jens Søndergaard
- Department of Bioscience, Aarhus University, Roskilde DK-4000, Denmark
| | - Sara Persson
- Swedish Museum of Natural History, Department of Environmental Research and Monitoring, Stockholm SE-10405, Sweden
| | - Cynthia A de Wit
- Department of Environmental Science, Stockholm University, Stockholm SE-10691, Sweden
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Buesum D-25761, Germany
| | - Lehnert Kristina
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Buesum D-25761, Germany.
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Bengtson Nash SM, Casa MV, Kawaguchi S, Staniland I, Bjerregaard P. Mercury levels in humpback whales, and other Southern Ocean marine megafauna. MARINE POLLUTION BULLETIN 2021; 172:112774. [PMID: 34364143 DOI: 10.1016/j.marpolbul.2021.112774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Mercury is a known potent neurotoxin. The biogeochemical cycle of mercury in the remote Antarctic region is still poorly understood, with Polar climate change contributing added complexity. Longitudinal biomonitoring of mercury accumulation in Antarctic marine megafauna can contribute top-down insight into the bio-physical drivers of wildlife exposure. The bioaccumulative nature of organic mercury renders high trophic predators at the greatest risk of elevated exposure. Humpback whales represent secondary consumers of the Antarctic sea-ice ecosystem and an ideal biomonitoring species for persistent and bioaccumulative compounds due to their extended life-spans. This study provides the first results of mercury accumulation in humpback whales, and places findings within the context of mercury accumulation in both prey, as well as six other species of Antarctic marine megafauna. Combined, these findings contribute new baseline information regarding mercury exposure to Antarctic wildlife, and highlights methodological prerequisites for routine mercury biomonitoring in wildlife via non-lethally biopsied superficial tissues.
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Affiliation(s)
- Susan M Bengtson Nash
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD 4111, Australia.
| | - Maria Valeria Casa
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD 4111, Australia
| | - So Kawaguchi
- Australian Antarctic Division, Kingston, TAS 7050, Australia
| | - Iain Staniland
- British Antarctic Survey, Cambridge CB3 0ET, England, United Kingdom of Great Britain and Northern Ireland
| | - Poul Bjerregaard
- Department of Biology, The University of Southern Denmark, 5230 Odense M, Denmark
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Fragão J, Bessa F, Otero V, Barbosa A, Sobral P, Waluda CM, Guímaro HR, Xavier JC. Microplastics and other anthropogenic particles in Antarctica: Using penguins as biological samplers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 788:147698. [PMID: 34134362 DOI: 10.1016/j.scitotenv.2021.147698] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 05/07/2023]
Abstract
Microplastics (< 5 mm in size) are known to be widespread in the marine environment but are still poorly studied in Polar Regions, particularly in the Antarctic. As penguins have a wide distribution around Antarctica, three congeneric species: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarcticus) and gentoo penguins (Pygoscelis papua) were selected to evaluate the occurrence of microplastics across the Antarctic Peninsula and Scotia Sea. Scat samples (used as a proxy of ingestion), were collected from breeding colonies over seven seasons between 2006 and 2016. Antarctic krill (Euphausia superba), present in scat samples, contributed 85%, 66% and 54% of the diet in terms of frequency of occurrence to the diet of Adélie, gentoo and chinstrap penguins, respectively. Microplastics were found in 15%, 28% and 29% scats of Adélie, chinstrap and gentoo penguin respectively. A total of 92 particles were extracted from the scats (n = 317) and 32% (n = 29) were chemically identified via micro-Fourier Transform Infrared Spectroscopy (μ-FTIR). From all the particles extracted, 35% were identified as microplastics, particularly polyethylene (80%) and polyester (10%). It was not possible to ascertain the identification of the remaining 10% of samples. Other anthropogenic particles were identified in 55% of samples, identified as cellulose fibres. The results show a similar frequency of occurrence of particles across all colonies, suggesting there is no particular point source for microplastic pollution in the Scotia Sea. Additionally, no clear temporal variation in the number of microplastics in penguins was observed. Overall, this study reveals the presence of microplastics across Antarctica, in three penguin species and offers evidence of other anthropogenic particles in high numbers. Further research is needed to better understand the spatio-temporal dynamics, fate and effect of microplastics on these ecosystems, and improve plastic pollution policies in Antarctica.
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Affiliation(s)
- Joana Fragão
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, 3000-456 Coimbra, Portugal.
| | - Filipa Bessa
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, 3000-456 Coimbra, Portugal
| | - Vanessa Otero
- LAQV-REQUIMTE, Department of Conservation and Restoration, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Monte da Caparica, Portugal; VICARTE, Department of Conservation and Restoration, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Monte da Caparica, Portugal
| | - Andrés Barbosa
- Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, 28006 Madrid, Spain
| | - Paula Sobral
- Marine and Environmental Sciences Centre, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Monte da Caparica, Portugal
| | - Claire M Waluda
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Hugo R Guímaro
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, 3000-456 Coimbra, Portugal
| | - José C Xavier
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, 3000-456 Coimbra, Portugal; British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
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Bestley S, Ropert-Coudert Y, Bengtson Nash S, Brooks CM, Cotté C, Dewar M, Friedlaender AS, Jackson JA, Labrousse S, Lowther AD, McMahon CR, Phillips RA, Pistorius P, Puskic PS, Reis AODA, Reisinger RR, Santos M, Tarszisz E, Tixier P, Trathan PN, Wege M, Wienecke B. Marine Ecosystem Assessment for the Southern Ocean: Birds and Marine Mammals in a Changing Climate. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.566936] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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9
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Cloning and characterization of a heat shock protein 70 gene from the yellowstripe goby, Mugilogobius chulae : Evidence for its significance in biomonitoring of environmental pollution. GENE REPORTS 2018. [DOI: 10.1016/j.genrep.2018.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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