Cooperative effect of crude oil and low salinity on the digestive glands lipid composition of the White Sea blue mussels Mytilus edulis

Abstract

The response of the organism to the pollutant impact is influenced by a variety of abiotic and biotic environmental factors that may have a synergistic or antagonistic effect on the biodegradation, accumulation, distribution and elimination of the xenobiotics. It is known that lipophilic organic contaminants including oil hydrocarbons can be accumulated in lipid-rich tissues of marine animals, thus causing changes in biosynthesis and transport of phospholipids and triacylglycerols, as well as in the physical state of biological membranes. The cooperative effect of crude oil and low salinity on digestive gland lipid composition of the White Sea blue mussels Mytilus edulis L. was studied in aquarium experiment. Low salinity (15‰) impact reflects on the lipid composition indicating high energy costs directed to acclimation of the mussels to new environmental conditions. However, the response of the lipid composition on the crude oil effect is almost not dependent on the ambient salinity, and is mainly determined by exposure duration to crude oil and its dose in aquarium water. On the third experimental day a significant increase in the cholesterol/phospholipids ratio and the subsequent its recovery to initial level possibly indicate the development of the protective compensatory mechanisms to provide low permeability of cell membranes in digestive glands under crude oil pollution. It was observed that the leading factor contributing the lipid composition modifications in blue mussel digestive glands is crude oil effect, mainly in its higher concentrations.

Changes of Heart Rate and Lipid Composition in Mytilus Edulis and Modiolus Modiolus Caused by Crude Oil Pollution and Low Salinity Effects

“…Horse mussels typically inhabit the subtidal zone and have no direct exposure to tidal cycles. At the same time, the biochemical response at the level of the main lipid classes in horse mussels under all the studied crude oil concentrations was in many respects similar to the response of blue mussels [24,25]. As was the case with the blue mussels [24], the Ch/PL ratio in the horse mussel gills decreased on the tenth day under all the studied crude oil concentrations, indicating an increased permeability of the biological membranes at the end of the experiment [12].…”

“…It is well known that neutral lipids or TAG are also sequestered by autophagy in the lysosomes of mussels exposed to PAHs [35]. As with the blue mussels [25], the increased Ch/PL ratio in the horse mussel digestive glands indicated a decrease in the permeability of the biological membranes on the third day of the experiment and on the first experimental day under exposure to the high crude oil concentration. At the same time, the reduction in the TAG levels in the digestive glands of the horse mussels probably reflects the utilization of the lipid pool in various biosynthetic processes including additional synthesis of the membrane lipids.…”

“…The results of the lipid classes' content in gills and digestive glands of blue mussels have been described earlier in our articles [24,25] and are not included in this paper.…”

“…Pollution-triggered activation of lipid peroxidation processes causes membrane phospholipid modifications that lead to a disturbance of the biological membrane integrity and permeability [13,14]. Our earlier studies of the modifications of the lipid and fatty acid composition in blue mussels in response to different concentrations of cadmium and copper ions as well as diesel fuel in seawater revealed the possibility of using some lipids and fatty acids as biomarkers to demonstrate the adverse effect of pollutants [24,25,29].…”