ABSTRACT
Bottlenose dolphins (Tursiops truncatus) are keystone and sentinel species in the world's oceans. We studied correlations between per- and polyfluoroalkyl substances (PFAS) and their stress axis. We investigated associations between plasma biomarkers of 12 different PFAS variants and three cortisol pools (total, bound, and free) in wild T. truncatus from estuarine waters of Charleston, South Carolina (n = 115) and Indian River Lagoon, Florida (n = 178) from 2003 to 2006, 2010-2013, and 2015. All PFAS and total cortisol levels for these dolphins were previously reported; bound cortisol levels and free cortisol calculations have not been previously reported. We tested null hypotheses that levels of each PFAS were not correlated with those of each cortisol pool. Free cortisol levels were lower when PFOS, PFOA, and PFHxS biomarker levels were higher, but free cortisol levels were higher when PFTriA was higher. Bound cortisol levels were higher when there were higher PFDA, PFDoDA, PFDS, PFTeA, and PFUnDA biomarkers. Total cortisol was higher when PFOA was lower, but total cortisol was higher when PFDA, PFDoDA, PFTeA, and PFTriA were higher. Additional analyses indicated sex and age trends, as well as heterogeneity of effects from the covariates carbon chain length and PFAS class. Although this is a cross-sectional observational study and, therefore, could reflect cortisol impacts on PFAS toxicokinetics, these correlations are suggestive that PFAS impacts the stress axis in T. truncatus. However, if PFAS do impact the stress axis of dolphins, it is specific to the chemical structure, and could affect the individual pools of cortisol differently. It is critical to conduct long-term studies on these dolphins and to compare them to populations that have no or little expose to PFAS.
Subject(s)
Biomarkers , Bottle-Nosed Dolphin , Hydrocortisone , Water Pollutants, Chemical , Animals , Bottle-Nosed Dolphin/metabolism , Hydrocortisone/blood , Hydrocortisone/metabolism , Environmental Monitoring , Fluorocarbons , Stress, Physiological , Female , Male , South Carolina , FloridaABSTRACT
Cumulative exposure to sub-lethal anthropogenic stressors can affect the health and reproduction of coastal cetaceans and hence their population viability. To date, we do not have a clear understanding of the notion of health for cetaceans in an ecological context; that is, how health status affects the ability of individuals to survive and reproduce. Here, we make use of a unique health-monitoring programme of estuarine bottlenose dolphins in South Carolina and Florida to determine de novo changes in biological pathways, using untargeted plasma metabolomics, depending on the health status of individuals obtained from veterinary screening. We found that individuals that were in a poor health state had lower circulating amino acids pointing towards increased involvement of gluconeogenesis (i.e., new formation of glucose). More mechanistic work is needed to disentangle the interconnection between health and energy metabolism in cetaceans to mediate potential metabolic constraints they may face during periods of stress.
Subject(s)
Bottle-Nosed Dolphin , Animals , Bottle-Nosed Dolphin/metabolism , Gluconeogenesis , Metabolomics , ProteolysisABSTRACT
Polychlorinated biphenyls (PCBs) have been assessed for immunotoxicity; however, humans and wildlife are exposed to multiple PCBs environmentally. Therefore, the aim of this study was to examine the effects of a complex 37 PCB congener mixture identified in blubber specific to dolphins residing in the estuarine waters of Charleston, South Carolina. Immunotoxicity was determined in adult female B6C3F1 mice by assessing lymphocyte proliferation, splenic and thymic immunophenotypes, and IgM production. Mice were exposed via oral gavage to the PCB-mixture (0, 1.8, 3.6, 7.1, or 14.3 mg/kg/day) for 28 days to yield a targeted total administered dose (TAD) 0, 50, 100, 200, or 400 mg/kg. Significant increased liver weight occurred at the highest treatment. IgM production was suppressed compared to control for all treatments. Numbers of thymic CD4+/CD8+, CD4-/CD8-, and CD4+/CD8- cells were not altered, but numbers of thymic CD4-/CD8+ cells were significantly increased in the highest treatment. Lymphocyte proliferation was not markedly affected by any treatment. The numbers of splenic CD4/CD8 T-cells or MHCII+ cells were not significantly changed. Humoral immunity using the plaque-forming cell assay for determining the specific IgM antibody-forming cell response appeared to be the most sensitive endpoint affected. As the lowest concentration tested resulted in decreased IgM production and total and free thyroxine (T4) serum levels a NOAEL was not identified. The calculated ED50 for suppression of IgM production was 2.4 mg/kg/day.
Subject(s)
Immunotoxins/toxicity , Polychlorinated Biphenyls/toxicity , Thyroid Gland/drug effects , Thyroid Hormones/metabolism , Animals , Environmental Pollutants , Female , Mice , Thyroid Gland/metabolismABSTRACT
Plasma glucocorticoid (CORT) levels are one measure of stress in wildlife and give us insight into natural processes relevant to conservation issues. Many studies use total CORT concentrations to draw conclusions about animals' stress state and response to their environment. However, the blood of tetrapods contains corticosteroid-binding globulin (CBG), which strongly binds most circulating CORT. Only free CORT (CORT not bound by CBG) leaves the circulation and exerts biological effects on CORT-sensitive tissues. Measuring free CORT concentrations provides insight to an animal's stress response that cannot be revealed by simply measuring total CORT. To calculate free CORT concentrations in plasma or serum samples, one needs three measurements: the binding affinity of CBG for CORT (which varies by species), the total CORT concentration in the sample and the maximum corticosteroid binding capacity (MCBC) of CBG in the sample. Here, we detail the measurement of CBG binding capacity. We compare and contrast the three main methods to measure MCBC: charcoal, cell harvester and dialysis. Each is defined by the means by which free and bound CORT are separated. We weigh the relative merits and challenges of each. We conclude that sample volume, species and taxon binding specificity, and availability of equipment are the primary considerations in selecting the appropriate separation method. For most mammals, the charcoal method is recommended. For birds, the harvester method has critical advantages over the charcoal method. The dialysis method is widely regarded as the gold standard and has lower equipment costs but is more time-intensive and costly in terms of radioactive isotope needed and is less suited to processing large numbers of samples. The binding capacity of CBG varies tremendously within and among the bird and marine mammal species studied, and we discuss the implication of this variation for understanding the role of stress in wildlife.
ABSTRACT
Temporal trends in plasma concentrations of per- and polyfluoroalkyl substances (PFAS) in free-ranging bottlenose dolphins (Tursiops truncatus) inhabiting two geographic areas: Indian River Lagoon, Florida over the years 2003-2015 and the waters surrounding Charleston, South Carolina over 2003-2013, were examined. Nine PFAS met the inclusion criteria for analysis based on percent of values below level of detection and sampling years. Proportionate percentiles parametric quantile regression assuming lognormal distributions was used to estimate the average ratio of PFAS concentrations per year for each chemical. Plasma concentrations decreased over time for perfluorodecanoate (PFDA), perfluorohexane sulfonate (PFHxS), perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and perfluoroundecanoate (PFUnDA) in both locations. Perfluorononanoate (PFNA) decreased with time in Indian River Lagoon dolphins. Perfluorododecanoate (PFDoDA) concentrations significantly increased over time among female Indian River Lagoon dolphins. Regulation and phaseout of specific PFAS groups may have led to the decreasing levels of those PFAS and increasing levels of other replacement PFAS.
Subject(s)
Bottle-Nosed Dolphin , Fluorocarbons , Animals , Female , Florida , Rivers , South CarolinaABSTRACT
Natural and anthropogenic stressors have been reported to impact the health of marine mammals. Therefore, investigation of quantifiable biomarkers in response to stressors is required. We hypothesized that stress protein expression would be associated with biological and health variables in wild and managed-care bottlenose dolphins (Tursiops truncatus). To test this hypothesis, our study objectives were to (1) determine if stress proteins in skin, white blood cells (WBCs), and plasma could be measured with an antibody-based microarray, (2) measure stress-protein expression relative to biological data (location, sex, age, environment), and (3) determine if stress-protein expression was associated with endocrine, hematological, biochemical and serological variables and gene expression in bottlenose dolphins. Samples were collected from two wild groups (nâ¯=â¯28) and two managed-care groups (nâ¯=â¯17). Proteins involved in the HPA axis, apoptosis, proteotoxicity, and inflammation were identified as stress proteins. The expression of 3 out of 33 proteins was significantly (Pâ¯<â¯0.05) greater in skin than plasma and WBCs. Male dolphins had significantly greater expression levels for 10 proteins in skin compared to females. The greatest number of stress-associated proteins varied by the dolphins' environment; nine were greater in managed-care dolphins and 15 were greater in wild dolphins, which may be related to wild dolphin disease status. Protein expression in skin and WBCs showed many positive relationships with measures of plasma endocrinology and biochemistry. This study provides further understanding of the underlying mechanisms of the stress response in bottlenose dolphins and application of a combination of novel methods to measure stress in wildlife.
Subject(s)
Bottle-Nosed Dolphin/metabolism , Ecosystem , Heat-Shock Proteins/metabolism , Stress, Physiological , Animals , Blood Proteins/metabolism , Bottle-Nosed Dolphin/physiology , Female , Hypothalamo-Hypophyseal System , Leukocytes/metabolism , Male , Pituitary-Adrenal System , Skin/metabolismABSTRACT
Free-ranging Atlantic bottlenose dolphins (n = 360) from two southeastern U.S. estuarine sites were given comprehensive health examinations between 2003 and 2015 as part of a multi-disciplinary research project focused on individual and population health. The study sites (and sample sizes) included the Indian River Lagoon (IRL), Florida, USA (n = 246) and Charleston harbor and associated rivers (CHS), South Carolina, USA (n = 114). Results of a suite of clinicoimmunopathologic tests revealed that both populations have a high prevalence of infectious and neoplastic disease and a variety of abnormalities of their innate and adaptive immune systems. Subclinical infections with cetacean morbillivirus and Chlamydiaceae were detected serologically. Clinical evidence of orogenital papillomatosis was supported by the detection of a new strain of dolphin papillomavirus and herpesvirus by molecular pathology. Dolphins with cutaneous lobomycosis/lacaziasis were subsequently shown to be infected with a novel, uncultivated strain of Paracoccidioides brasiliensis, now established as the etiologic agent of this enigmatic disease in dolphins. In this review, innate and adaptive immunologic responses are compared between healthy dolphins and those with clinical and/or immunopathologic evidence of infection with these specific viral, bacterial, and fungal pathogens. A wide range of immunologic host responses was associated with each pathogen, reflecting the dynamic and complex interplay between the innate, humoral, and cell-mediated immune systems in the dolphin. Collectively, these studies document the comparative innate and adaptive immune responses to various types of infectious diseases in free-ranging Atlantic bottlenose dolphins. Evaluation of the type, pattern, and degree of immunologic response to these pathogens provides novel insight on disease immunopathogenesis in this species and as a comparative model. Importantly, the data suggest that in some cases infection may be associated with subclinical immunopathologic perturbations that could impact overall individual and population health.
Subject(s)
Bottle-Nosed Dolphin/immunology , Chlamydiaceae Infections/veterinary , Lobomycosis/veterinary , Morbillivirus Infections/veterinary , Paracoccidioidomycosis/veterinary , Adaptive Immunity , Animals , Antibodies, Bacterial/blood , Antibodies, Fungal/blood , Antibodies, Viral/blood , Atlantic Ocean , Bottle-Nosed Dolphin/blood , Bottle-Nosed Dolphin/microbiology , Bottle-Nosed Dolphin/virology , Chlamydiaceae Infections/epidemiology , Chlamydiaceae Infections/immunology , Coinfection/veterinary , Communicable Diseases, Emerging/veterinary , Estuaries , Immunity, Innate , Lobomycosis/epidemiology , Lobomycosis/immunology , Morbillivirus Infections/epidemiology , Morbillivirus Infections/immunology , Paracoccidioidomycosis/epidemiology , Paracoccidioidomycosis/immunology , South CarolinaABSTRACT
Concentrations of 11 PFASs were determined in muscle and whole fish for six species collected from Charleston, South Carolina (SC) for the assessment of potential health risks to humans and wildlife. Across all species and capture locations, total PFAS levels in whole fish were significantly higher than fillets by a factor of two- to three-fold. Mean ∑PFAS concentrations varied from 12.7 to 33.0â¯ng/g wet weight (ww) in whole fish and 6.2-12.7â¯ng/g ww in fillets. For individual whole fish, ∑PFASs ranged from 12.7â¯ng/g ww in striped mullet to 85.4â¯ng/g ww in spotted seatrout, and in fillets individual values ranged from 6.2â¯ng/g ww in striped mullet to 27.9â¯ng/g ww in spot. The most abundant compound in each species was perfluorooctane sulfonate (PFOS), comprising 25.5-69.6% of the ∑PFASs. Striped mullet had significantly lower relative amounts of PFOS compared to all other species and higher relative amounts of PFUnDA compared to Atlantic croaker, spotted seatrout, and spot. Unlike whole fish, PFAS levels in fillets varied significantly by location with higher ∑PFOS from the Ashley River than the Cooper River and Charleston Harbor, which reflects the levels of PFASs contamination in these systems. In whole fish, differences in relative concentrations of PFOS, PFNA, and PFDA occurred by capture location, suggestive of different sources. PFOS concentrations for southern flounder and spotted seatrout fillets were within the advisory range to limit fish consumption to 4 meals a month. PFOS levels exceeded screening values to protect mammals in 83% of whole fish examined and represent a potential risk to wildlife predators such as dolphins.
Subject(s)
Alkanesulfonic Acids , Environmental Monitoring , Fluorocarbons , Seafood/statistics & numerical data , Water Pollutants, Chemical , Animals , Humans , Risk Assessment , South Carolina , United StatesABSTRACT
We report the discovery of the first cetacean pegivirus (family Flaviviridae) using a next-generation sequencing approach. One of two infected bottlenose dolphins had elevated activities of liver enzymes, which may suggest hepatocellular injury. Further research is needed to determine the epidemiology and pathogenicity of dolphin pegivirus.
Subject(s)
Bottle-Nosed Dolphin/virology , Flaviviridae Infections/veterinary , Flaviviridae/classification , Flaviviridae/isolation & purification , Animals , Computational Biology , Enzymes/blood , Flaviviridae/genetics , Flaviviridae Infections/virology , Florida , High-Throughput Nucleotide Sequencing , Liver Function Tests , Sequence Analysis, DNAABSTRACT
Fecal samples collected from free-ranging Atlantic bottlenose dolphins (BDs) in the Indian River Lagoon of Florida were processed for viral discovery using a next-generation sequencing (NGS) approach. A 693-bp contig identified in the NGS data was nearly identical to the partial L1 gene sequence of a papillomavirus (PV) previously found in a penile papilloma in a killer whale (Orcinus orca). Based on this partial bottlenose dolphin papillomavirus (BDPV) sequence, a nested inverse PCR and primer-walking strategy was employed to generate the complete genome sequence. The full BDPV genome consisted of 7299 bp and displayed a typical PV genome organization. The BDPV E6 protein contained a PDZ-binding motif, which has been shown to be involved in carcinogenic transformation involving high-risk genital human PVs. Screening of 12 individual fecal samples using a specific endpoint PCR assay revealed that the feces from a single female BD displaying a genital papilloma was positive for the BDPV. Genetic analysis indicated that this BDPV (Tursiops truncatus papillomavirus 8; TtPV8) is a new type of Dyopipapillomavirus 1, previously sequenced from an isolate obtained from a penile papilloma in a harbor porpoise (Phocoena phocoena). Although only a partial L1 sequence has been determined for a PV detected in a killer whale genital papilloma, our finding of a nearly identical sequence in an Atlantic BD may indicate that members of this viral species are capable of host jumping. Future work is needed to determine if this virus is a high-risk PV that is capable of inducing carcinogenic transformation and whether it poses a significant health risk to wild delphinid populations.
Subject(s)
Bottle-Nosed Dolphin/virology , Papillomaviridae/genetics , Tumor Virus Infections/veterinary , Animals , Female , Florida , Genomics , Papillomaviridae/classification , Papillomaviridae/isolation & purification , Phylogeny , Rivers/virology , Tumor Virus Infections/virology , Viral Proteins/geneticsABSTRACT
Substituted diphenylamine antioxidants (SDPAs) and benzotriazole UV stabilizers (BZT-UVs) are additives used in industrial and commercial applications to prevent degradation by oxidation and are contaminants of emerging environmental concern. Little is known about the fate of these contaminants in wildlife, particularly in reptiles, birds and marine mammals. Nine SDPAs and six BZT-UVs were measured in blood plasma of seven fish species, snapping turtles (Chelydra serpentina), double-crested cormorants (Phalacrocorax auritus), and bottlenose dolphins (Tursiops truncatus) from various locations in North America. Plasma SDPAs were more frequently (90-100%) detected and with higher concentrations (median: 25-270â¯pgâ¯g-1, wet weight (ww)) in organisms from urban areas than rural locations (median:
Subject(s)
Diphenylamine/blood , Environmental Monitoring , Triazoles/blood , Water Pollutants, Chemical/blood , Animals , Antioxidants/metabolism , Birds/blood , Dolphins/blood , Fishes/blood , Great Lakes Region , North America , Turtles/bloodABSTRACT
Fish consumption is an important route of exposure to persistent organic pollutants (POPs) in dolphins as well as humans. In order to assess the potential risks associated with these contaminants, 39 whole fish and 37 fillets from fish representing species consumed by dolphins and humans captured from Charleston Harbor and tributaries, South Carolina, USA, were measured for a suite of POPs. Polychlorinated biphenyls (PCBs) were the predominant contaminant with concentrations ranging from 5.02 to 232.20â¯ng/g in whole fish and 5.42-131.95â¯ng/g in fillets (weight weight ww) followed by total organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). Total POPs levels varied by location and species with general trends indicating significantly higher levels in fish from the Cooper (93.4â¯ng/g ww) and Ashley Rivers (56.2â¯ng/g ww) compared to Charleston Harbor (31.6â¯ng/g ww). Mullet and spot were found to have significantly higher PCBs, OCPs and total POPs, 2-3 times higher than red drum; mullet were also significantly higher in OCPs compared to seatrout. PCB concentrations in whole fish and fillets exceeded EPA human screening values for cancer risk in all fish sampled. For PCBs in fillets, all samples had values of maximum allowable meals per month that were less than the EPA, FDA guidelines for recommended fish meals per month, suggesting lower (more stringent) allowable fish meals per month. All fish exceeded PBDE wildlife values and all fish except two exceeded the level where 95% of the dolphin population would have tissue levels below the health effect threshold. Considering that POP concentrations in fish potentially consumed by humans exceed human health effect thresholds levels, consumption advisories should be considered as a prudent public health measure.
Subject(s)
Environmental Pollutants , Hydrocarbons, Chlorinated , Polychlorinated Biphenyls , Water Pollutants, Chemical , Animals , Fishes , Halogenated Diphenyl Ethers , Humans , Risk Assessment , South Carolina , United StatesABSTRACT
The genome sequence of a papillomavirus was determined from fecal samples collected from bottlenose dolphins in the Indian River Lagoon, FL. The genome was 7,772 bp and displayed a typical papillomavirus genome organization. Phylogenetic analysis supported the bottlenose dolphin papillomavirus as being a novel type of Omikronpapillomavirus1.
ABSTRACT
Bottlenose dolphins Tursiops truncatus are the most common apex predators found in coastal and estuarine ecosystems along the southeastern coast of the USA, where these animals are exposed to multiple chemical pollutants and microbial agents. In this review, we summarize the results of investigations of environmental exposures evaluated in 360 free-ranging dolphins between 2003 and 2015. Bottlenose dolphins inhabiting the Indian River Lagoon, Florida (IRL, n = 246), and coastal waters of Charleston, South Carolina (CHS, n = 114), were captured, given comprehensive health examinations, and released as part of a multidisciplinary and multi-institutional study of individual and population health. High concentrations of persistent organic pollutants including legacy contaminants (DDT and other pesticides, polychlorinated biphenyl compounds) as well as 'emerging' contaminants (polybrominated diphenyl ethers, perfluorinated compounds) were detected in dolphins from CHS, with lower concentrations in the IRL. Conversely, the concentrations of mercury in the blood and skin of IRL dolphins were among the highest reported worldwide and approximately 5 times as high as those found in CHS dolphins. A high prevalence of resistance to antibiotics commonly used in humans and animals was detected in bacteria isolated from fecal, blowhole, and/or gastric samples at both sites, including methicillin-resistant Staphylococcus aureus (MRSA) at CHS. Collectively, these studies illustrate the importance of long-term surveillance of estuarine populations of bottlenose dolphins and reaffirm their important role as sentinels for marine ecosystems and public health.
Subject(s)
Bottle-Nosed Dolphin , Environmental Monitoring , Animals , Risk Assessment , Southeastern United States/epidemiologyABSTRACT
Immune and endocrine responses play a critical role in allowing animals to adjust to environmental perturbations. We measured immune and endocrine related markers in multiple samples from individuals from two managed-care care dolphin groups (n = 82 samples from 17 dolphins and single samples collected from two wild dolphin populations: Indian River Lagoon, (IRL) FL (n = 26); and Charleston, (CHS) SC (n = 19). The immune systems of wild dolphins were more upregulated than those of managed-care-dolphins as shown by higher concentrations of IgG and increases in lysozyme, NK cell function, pathogen antibody titers and leukocyte cytokine transcript levels. Collectively, managed-care care dolphins had significantly lower levels of transcripts encoding pro-inflammatory cytokine TNF, anti-viral MX1 and INFα and regulatory IL-10. IL-2Rα and CD69, markers of lymphocyte activation, were both lower in managed-care care dolphins. IL-4, a cytokine associated with TH2 activity, was lower in managed-care care dolphins compared to the free-ranging dolphins. Differences in immune parameters appear to reflect the environmental conditions under which these four dolphin populations live which vary widely in temperature, nutrition, veterinary care, pathogen/contaminant exposures, etc. Many of the differences found were consistent with reduced pathogenic antigenic stimulation in managed-care care dolphins compared to wild dolphins. Managed-care care dolphins had relatively low TH2 lymphocyte activity and fewer circulating eosinophils compared to wild dolphins. Both of these immunologic parameters are associated with exposure to helminth parasites which is uncommon in managed-care care dolphins. Less consistent trends were observed in a suite of hormones but significant differences were found for cortisol, ACTH, total T4, free T3, and epinephrine. While the underlying mechanisms are likely multiple and complex, the marked differences observed in the immune and endocrine systems of wild and managed-care care dolphins appear to be shaped by their environment.
Subject(s)
Dolphins/immunology , Dolphins/physiology , Endocrine System/physiology , Animals , Female , MaleABSTRACT
Perfluoroalkyl acids (PFAAs) are highly stable compounds that have been associated with immunotoxicity in epidemiologic studies and experimental rodent models. Lengthy half-lives and resistance to environmental degradation result in bioaccumulation of PFAAs in humans and wildlife. Perfluorooctane sulfonate (PFOS), the most prevalent PFAA detected within the environment, is found at high levels in occupationally exposed humans. We have monitored the environmental exposure of dolphins in the Charleston, SC region for over 10 years and levels of PFAAs, and PFOS in particular, were significantly elevated. As dolphins may serve as large mammal sentinels to identify the impact of environmental chemical exposure on human disease, we sought to assess the effect of environmental PFAAs on the cellular immune system in highly exposed dolphins. Herein, we utilized a novel flow cytometry-based assay to examine T cell-specific responses to environmental PFAA exposure ex vivo and to exogenous PFOS exposure in vitro. Baseline PFOS concentrations were associated with significantly increased CD4+ and CD8+ T cell proliferation from a heterogeneous resident dolphin population. Further analysis demonstrated that in vitro exposure to environmentally relevant levels of PFOS promoted proinflammatory cytokine production and proliferation in a dose-dependent manner. Collectively, these findings indicate that PFOS is capable of inducing proinflammatory interferon-gamma, but not immunoregulatory interleukin-4 production in T cells, which may establish a state of chronic immune activation known to be associated with susceptibility to disease. These findings suggest that PFOS directly dysregulates the dolphin cellular immune system and has implications for health hazards. Copyright © 2017 John Wiley & Sons, Ltd.
Subject(s)
Alkanesulfonic Acids/toxicity , Bottle-Nosed Dolphin/immunology , Environmental Exposure/adverse effects , Fluorocarbons/toxicity , Lymphocyte Activation/drug effects , T-Lymphocytes/drug effects , Animals , Cell Proliferation/drug effects , Cells, Cultured , Cytokines/immunology , T-Lymphocytes/cytology , Water Pollutants, Chemical/toxicityABSTRACT
The Deepwater Horizon oil spill was one of the worst environmental disasters on record in the United States. Response efforts to reduce the magnitude of the oil slick included the use of thousands of gallons of the chemical dispersant Corexit™ in surface and deep-water environments. The immunotoxicity of Louisiana sweet crude oil and the chemical dispersant Corexit was examined using lymphocyte proliferation (LP) and natural killer cell (NK) assays as measures of impact on the adaptive (LP) and innate (NK) immune response in bottlenose dolphins. Study results show that both high-energy media-accommodated fractions (MAF) and chemically enhanced MAF (CEMAF) mixtures modulate immune function. Following exposure to Louisiana sweet crude, both B- and T-cell proliferation of white blood cells was increased for all exposure concentrations, compared to control; however, this increase was only significant for the 50% and 100% treatments. In contrast, exposure of white blood cells to the CEMAF mixture significantly decreased both T- and B-cell proliferation in the 25%, 50% and 100% treatments. NK cell activity was enhanced significantly by CEMAF mixtures for the 50% and 100% treatments. The immunosuppression of LP at environmentally relevant concentrations of oil and dispersant suggests that marine mammals may be unable to mount an adequate defense against xenobiotic threats following exposure to oil and dispersant, leaving them more susceptible to disease. In contrast, NK cell activity was significantly enhanced, which may increase an organism's tumor or viral surveillance ability by mounting an enhanced immune response. Copyright © 2016 John Wiley & Sons, Ltd.
Subject(s)
Bottle-Nosed Dolphin/blood , Lipids/toxicity , Lymphocytes/drug effects , Petroleum Pollution/adverse effects , Petroleum/toxicity , Water Pollutants, Chemical/toxicity , Animals , Cell Culture Techniques , Cell Proliferation/drug effects , Cells, Cultured , Environmental Monitoring/methods , Killer Cells, Natural/drug effects , Killer Cells, Natural/immunology , Lymphocytes/immunology , Petroleum Pollution/prevention & controlABSTRACT
Cutaneous granulomas in dolphins were believed to be caused by Lacazia loboi, which also causes a similar disease in humans. This hypothesis was recently challenged by reports that fungal DNA sequences from dolphins grouped this pathogen with Paracoccidioides brasiliensis. We conducted phylogenetic analysis of fungi from 6 bottlenose dolphins (Tursiops truncatus) with cutaneous granulomas and chains of yeast cells in infected tissues. Kex gene sequences of P. brasiliensis from dolphins showed 100% homology with sequences from cultivated P. brasiliensis, 73% with those of L. loboi, and 93% with those of P. lutzii. Parsimony analysis placed DNA sequences from dolphins within a cluster with human P. brasiliensis strains. This cluster was the sister taxon to P. lutzii and L. loboi. Our molecular data support previous findings and suggest that a novel uncultivated strain of P. brasiliensis restricted to cutaneous lesions in dolphins is probably the cause of lacaziosis/lobomycosis, herein referred to as paracoccidioidomycosis ceti.
Subject(s)
Animal Diseases/microbiology , Dermatomycoses/veterinary , Dolphins , Granuloma/veterinary , Paracoccidioides , Paracoccidioidomycosis/veterinary , Animal Diseases/pathology , Animals , Base Sequence , Biopsy , DNA, Fungal , Paracoccidioides/classification , Paracoccidioides/genetics , Paracoccidioides/isolation & purification , PhylogenyABSTRACT
Perfluoroalkyl phosphinic acids (PFPIAs) are perfluoroalkyl acids (PFAAs) that are used for their surfactant properties in a variety of applications, resulting in their presence in environmental waters; however, they have not been widely studied in biota. A survey of PFPIAs was conducted in fish, dolphins, and birds from various locations in North America. Northern pike (Esox lucius) were collected at two locations in 2011 near Montréal Island in the St. Lawrence River, Canada, double-crested cormorants (Phalacrocorax auritus) were collected from bird colonies in the Great Lakes in 2010-2012, and bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, FL and Charleston Harbor, SC were sampled in 2004-2009. PFPIAs had a detection frequency of 100% in all animals. This is the first report of PFPIAs in fish, dolphin, and bird plasma. Total PFPIA levels (mean ± standard deviation, 1.87 ± 2.17 ng/g wet weight (ww), range of 0.112-15.3 ng/g ww) were 1-2 orders of magnitude lower than those of perfluoroalkyl carboxylates (PFCA) and perfluoroalkanesulfonates (PFSA) in the same samples. The predominant congeners were 6:8 PFPIA (cormorants and pike) and 6:6 PFPIA (dolphins). Total PFPIAs in cormorants from Hamilton Harbour (5.02 ± 2.80 ng/g ww) were statistically higher than in other areas and taxonomic groups. The ubiquity of PFPIAs warrants further research on sources and effects of these unique compounds.