A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Brunch Russian Academy of Sciences, Vladivostok 690041, Russian Federation.
A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Brunch Russian Academy of Sciences, Vladivostok 690041, Russian Federation.
Sci Total Environ. 2020 Sep 10;734:139015. doi: 10.1016/j.scitotenv.2020.139015. Epub 2020 Apr 27.
The aim of our work was to assess whether the cellular processes in the nephrocytes of the long-lived mussel Crenomytilus grayanus tend to acclimation or destruction under trace metal contamination. Mussels were collected from three sites in the north-western Pacific Ocean: reference site, upwelling site, and a site highly contaminated with trace metals. Concentration, subcellular distribution of trace metals (Cd, Cu, Zn, and Pb) in the mussel kidneys, and ultrastructural alterations of the nephrocytes were studied. To assess the total load of accumulated trace metals, the total concentration coefficient (∑СС) was determined. In the kidneys of the reference C. grayanus, trace metals were eliminated from cell metabolism mainly by lysosomal granules or residue bodies. Under high levels of contamination, the defense mechanisms of C. grayanus are practically suppressed (no metallothionein-like protein peak, decreased content of granules) by the total effect of accumulated pollutants that leads to the destruction of cellular structures. Under natural conditions (upwelling site), increased accumulation of trace metals in the mussel kidneys did not lead to an increase in the number or size of lysosomal granules. However, abnormal high Cd accumulation in the kidneys caused the synthesis of high levels of metallothionein-like proteins that sequester most of the studied trace metals. To quickly lower the metal levels in nephrocytes under these conditions, a unique long-term acclimatory response - apocrine-like secretion in nephrocytes, which provides rapid elimination of me-MTLP complexes from the cell arose. Thus, our integrated study of the subcellular distribution of trace metals and ultrastructural alterations in nephrocytes allowed us to characterize the features of the structural and functional alterations in mussel cells under the field conditions tested.
我们的工作目的是评估在痕量金属污染下，长寿贻贝 Crenomytilus grayanus 的肾细胞的细胞过程是倾向于适应还是破坏。贻贝取自西北太平洋的三个地点：对照点、上升流点和一个高度污染痕量金属的地点。研究了贻贝肾脏中的痕量金属（Cd、Cu、Zn 和 Pb）的浓度、亚细胞分布以及肾细胞的超微结构变化。为了评估积累的痕量金属的总负荷，确定了总浓度系数（∑СС）。在对照点的 C. grayanus 肾脏中，痕量金属主要通过溶酶体颗粒或残余体从细胞代谢中消除。在高污染水平下，C. grayanus 的防御机制实际上被积累的污染物的总效应所抑制（没有金属硫蛋白样蛋白峰，颗粒含量降低），导致细胞结构的破坏。在自然条件下（上升流点），贻贝肾脏中痕量金属的积累增加并没有导致溶酶体颗粒的数量或大小增加。然而，肾脏中异常高的 Cd 积累导致合成高水平的金属硫蛋白样蛋白，这些蛋白将大部分研究的痕量金属螯合。为了在这些条件下快速降低肾细胞中的金属水平，一种独特的长期适应反应——肾细胞的顶泌样分泌出现了，这为从细胞中快速排出 Me-MTLP 复合物提供了可能。因此，我们对痕量金属的亚细胞分布和肾细胞超微结构变化的综合研究，使我们能够在测试的现场条件下，描述贻贝细胞结构和功能变化的特征。
