Trace element and lipidomic analysis of bottlenose dolphin blubber from the Yucatan coast: Lipid composition relationships.

Bottlenose dolphins (Tursiops truncatus) are found in coastal and estuarine ecosystems where they are in continuous contact with multiple abiotic and biotic stressors in the environment. Due to their role as predators, they can bioaccumulate contaminants and are considered sentinel organisms for monitoring the health of coastal marine ecosystems. The northern zonal coast of the Yucatan peninsula of Mexico has a high incidence of anthropogenic activities. The principal objectives of this study were two-fold: 1) to determine the presence of trace metals and their correlation with lipids in bottlenose dolphin blubber, and 2) to use a lipidomics approach to characterize their biological responses. Levels of trace elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Pb) were analyzed using ICP-MS and lipids were measured using a targeted lipidomics approach with LC-MS/MS. Spearman correlation analysis was used to identify associations between lipids and trace elements. The influences of gender, stranding codes, presence of stomach content, growth stages and body length were also analyzed. Blubber lipid composition was dominated by triacylglycerols (TAG). Our results demonstrated the presence of heavy-metal elements such as Cd and As, which were correlated with different lipid species, mainly the ceramides and glycerophospholipids, respectively. Organisms with Cd showed lower concentrations of ceramides (CER, HCER and DCER), TAG and cholesteryl esters (CE). Trace elements Cr, Co, As and Cd increased proportionately with body length. This study provides a novel insight of lipidomic characterization and correlations with trace elements in the bottlenose dolphin which might contribute to having a better understanding of the physiological functions and the risks that anthropogenic activities can bring to sentinel organisms from coastal regions.

Steroid hormones and estrogenic activity in the wastewater outfall and receiving waters of the Chascomús chained shallow lakes system (Argentina).

Natural and synthetic steroid hormones, excreted by humans and farmed animals, have been considered as important sources of environmental endocrine disruptors. A suite of estrogens, androgens and progestogens was measured in the wastewater treatment plant outfall (WWTPO) of Chascomús city (Buenos Aires province, Argentina), and receiving waters located downstream and upstream from the WWTPO, using solid phase extraction and high-performance liquid chromatography mass spectrometry. The following natural hormones were measured: 17ß-estradiol (E2), estrone (E1), estriol (E3), testosterone (T), 5α-dihydrotestosterone (DHT), progesterone (P), 17-hydroxyprogesterone (17OHP) and the synthetic estrogen 17α-ethinylestradiol (EE2). Also, in order to complement the analytical method, the estrogenic activity in these surface water samples was evaluated using the in vitro transactivation bioassay that measures the estrogen receptor (ER) activity using mammalian cells. All-natural steroid hormones measured, except 17OHP, were detected in all analyzed water samples. E3, E1, EE2 and DHT were the most abundant and frequently detected. Downstream of the WWTPO, the concentration levels of all compounds decreased reaching low levels at 4500 m from the WWTPO. Upstream, 1500 m from the WWTPO, six out of eight steroid hormones analyzed were detected: DHT, T, P, 17OHP, E3 and E2. Moreover, water samples from the WWTPO and 200 m downstream from it showed estrogenic activity exceeding that of the EC50 of the E2 standard curve. In sum, this work demonstrates the presence of sex steroid hormones and estrogenic activity, as measured by an in vitro assay, in superficial waters of the Pampas region. It also suggests the possibility of an unidentified source upstream of the wastewater outfall.

Blood Transcriptomics Analysis of Fish Exposed to Perfluoro Alkyls Substances: Assessment of a Non-Lethal Sampling Technique for Advancing Aquatic Toxicology Research.

In contrast to mammals, the blood from other vertebrates such as fish contains nucleated red cells. Using a fathead minnow ( Pimephales promelas) oligonucleotide microarray, we compared altered transcripts in the liver and whole blood after exposure to environmentally relevant concentrations of perfluorooctanesulfonic acid (PFOS) and a mixture of seven types of perfluoro alkyl substances (PFAS), including perfluorooctanoic acid (PFOA). We used quantitative polymerase chain reactions and cell-based assays to confirm the main effects and found that blood responded with a greater number of altered genes than the liver. The exposure to PFAS altered similar genes with central roles in a cellular pathway in both tissues, including estrogen receptor α and peroxisome proliferator activator ß and γ, indicating that the genes previously associated with PFAS exposure are differentially expressed in blood and liver. The altered transcripts are involved with cholesterol metabolism and mitochondrial function. Our data confirmed that PFAS are weak xenoestrogens and exert effects on DNA integrity. Gene expression profiling from blood samples not related with the immune system, including very-low-density lipoprotein, vitellogenin, estrogen receptor, and thyroid hormone receptor, demonstrated that blood is a useful tissue for assessing endocrine disruption in non-mammalian vertebrates. We conclude that the use of blood for non-lethal sampling in genomics studies is informative and particularly useful for assessing the effects of pollution in endangered species. Further, using blood will reduce animal use and widen the experimental design options for studying the effects of contaminant exposure on wildlife.

Gene expression profiling in the ovary of Queen conch (Strombus gigas) exposed to environments with high tributyltin in the British Virgin Islands.

Queen conch (Strombus gigas) are listed in CITES Appendix II. Populations may be declining due to anthropogenic inputs that include pollutants from boating activity. In the British Virgin Islands (BVI), some conch exhibit imposex, a condition in which male external genitalia are present in female conch. Previous studies suggest that tributyltin (TBT), an antifouling chemical used in boat paint, is correlated to increased incidence of imposex although the mechanisms leading to imposex are not known. The present study utilized a Queen conch microarray to measure the response of the ovarian transcriptome in conch inhabiting polluted environments with high TBT levels in the BVI. The polluted sites, Road Harbour (RH) and Trellis Bay (TB), are areas with high boating activity while the reference sites, Guana Island (GI) and Anegada (AN), are areas with low boating activity. There were 754 and 898 probes differentially expressed in the ovary of conch collected at RH and TB respectively compared to conch collected at GI. Of the genes that were differentially expressed at both sites, >10% were shared suggesting that these sites have additional environmental factors influencing gene expression patterns. Functional enrichment analysis showed that the biological processes of cell proliferation, translation, and oxidative stress were over-represented in the polluted sites. Gene set enrichment analysis revealed that transcripts involved in the biological processes of general metabolism, immune, lipid metabolism, and stress were affected in conch from polluted environments. Interestingly, altered stress genes appeared to be more prevalent in conch collected from RH than TB, corresponding to the higher TBT load at RH compared to TB. Our study shows that stress pathways are affected in conch ovary in environments that experience heavy boating activity in the BVIs, although we are unable to directly link changes at the transcriptomics level to high TBT levels.