abstract
This paper reports on an NMR metabolomics study of lipophilic extracts of Ruditapes philippinarum clams exposed to the hormonal contaminant 17-a-ethinylestradiol (EE2), at 17 degrees C and 21 degrees C. The results reveal that exposure at 17 degrees C triggers a weak response at low EE2 concentra-tions, suggestive of a slight increase in membrane rigidity, followed by lipid metabolic stability at higher EE2 concentrations. On the other hand, at 21 degrees C, lipid metabolism begins to respond at 125 ng/L EE2, with antioxidant docosahexaenoic acid (DHA) helping to tackle high-oxidative-stress conditions, in tandem with enhanced storage of triglycerides. Exposure to 625 ng/L EE2 (highest concentration) enhances phosphatidylcholine (PtdCho) and polyunsaturated fatty acid (PUFA) levels, their direct intercorrelation suggesting PUFA incorporation in new membrane phospholipids. This should lead to increased membrane fluidity, probably aided by a decrease in cholesterol. PUFA levels, considered a measure of membrane fluidity, were strongly (and positively) correlated to intracellular glycine levels, thus identifying glycine as the main osmolyte entering the cells under high stress. Membrane fluidity also seems to elicit the loss of taurine. This work contributes to the understanding of the mechanisms of response of R. philippinarum clams to EE2 in tandem with warming while unveiling novel potential markers of stress mitigation, namely high levels of PtdCho, PUFAs (or PtdCho/glycerophosphocholine and PtdCho/acetylcholine ratios) and linoleic acid and low PUFA/glycine ratios.
keywords
MYTILUS-GALLOPROVINCIALIS; H-1-NMR; 17-ALPHA-ETHINYLESTRADIOL; CONTAMINATION; SPECTROSCOPY; TOXICITY
subject category
Biochemistry & Molecular Biology; Chemistry
authors
Rodrigues, JA; Bispo, DSC; Silva, MG; Araújo, R; Soares, AMVM; Freitas, R; Gil, AM
our authors
Ana Maria Pissarra Coelho Gil
Associate Professor with Aggregation
Ana Rita Araújo Silva
PhD Student
Daniela Bispo
PhD Student
João A. Rodrigues
Junior Researcher
Mónica Isabel Garcia da Silva
Research FellowshipProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed within the CICECO-Aveiro Institute of Materials project (UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020) financed by national funds through the FCT/MCTES (PIDDAC). We are also grateful to the Portuguese National NMR Network (PTNMR), supported by FCT funds as the NMR spectrometer used is part of PTNMR and partially supported by Infrastructure Project No. 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and the FCT through PIDDAC). Thanks are due to CESAM-Center for Environmental and Marine Studies (UIDP/50017/2020, UIDB/50017/2020, LA/P/0094/2020). This work was also financially supported by the project BISPECIAl: BIvalveS under Polluted Environment and ClImate chAnge (POCI-01-0145-FEDER-028425) funded by FEDER, through COMPETE2020-Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds (OE), through FCT/MCTES. M.G.S. benefited from a research grant (MSc) (BI/CESAM/0043_2019/POCI-01-0145-FEDER-028425) under the project BISPECIAl: BIvalveS under Polluted Environment and ClImate change PTDC/CTA-AMB/28425/2017 (POCI-01-0145-FEDER-028425). D.S.B. acknowledges the Sociedade Portuguesa de Quimica and FCT for her Ph.D. grant SFRH/BD/150655/2020. R.A. thanks RNRMN for her grant through the Doctoral Program in NMR applied to Chemistry, Materials and Biosciences-PTNMRPhD (PD/00065/2013).