Metal accumulation and differentially expressed proteins in gill of oyster (Crassostrea hongkongensis) exposed to long-term heavy metal-contaminated estuary
Metal accumulation and differentially expressed proteins in gill of oyster (Crassostrea hongkongensis) exposed to long-term heavy metal-contaminated estuary
复制标题
长期暴露于重金属污染河口的牡蛎（Crassostrea hongkongensis）鳃中金属积累及差异表达蛋白
DOI：
10.1016/j.fsi.2014.03.029
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发表时间：
2014-06-01
影响因子：
4.7
通讯作者：
Huang, Miaoqin
中科院分区：
文献类型：
--
作者：
Luo, Lianzhong;Ke, Caihuan;Huang, Miaoqin
由于重金属污染严重威胁生态系统和粮食安全，有毒金属的生物累积和生物传播以及接触有毒金属的生物体的毒理学反应一直受到关注。然而，目前仍很少有研究关注某些生物体在特定环境中长期暴露于严重重金属污染的反应。本次调查中，从3个地点分别采集了香港牡蛎Crassostrea hongkongensis，这些地点分别受到不同浓度的重金属（如锌、铜、锰和铅等）污染。测定了3个地点的海水样本和蓝色内脏牡蛎的解剖组织中的重金属浓度，以估算环境中的金属污染水平和牡蛎不同组织中重金属的生物富集率。此外，采用蛋白质组学方法分析了长期重金属污染的牡蛎鳃中差异表达的蛋白质。结果表明，九龙江河口受到Cu、Zn污染较重，Cr、Ni、Mn等污染较轻，且Zn、Cu是牡蛎富集的主要金属，其富集浓度极高（相对组织干重而言，Zn含量超过3.0%，Cu含量约为2.0%），Cr、Ni、Mn等元素也有显着富集。重金属暴露的牡蛎鳃中的差异表达蛋白参与金属结合、转运保存、氧化还原平衡维持、应激反应、信号转导等多个细胞过程。在长期暴露于严重重金属污染的河口的牡蛎鳃中观察到重要的金属结合蛋白金属硫蛋白（MT）和颗粒细胞的表达显着上调（约10倍），研究表明，有毒金属与金属硫蛋白样蛋白（MTLP）结合以及以不溶形式将有毒金属储存在富金属颗粒（MRG）中是牡蛎解毒有毒金属和适应高水平金属污染环境的重要策略。长期暴露于重金属污染环境的牡蛎鳃中检测到大多数应激和免疫反应蛋白，如热休克蛋白（HSP）、细胞外超氧化物歧化酶（ECSOD）和cavortin，以及细胞氧化还原反应相关蛋白如20G-Fe（II）加氧酶家族氧化还原酶、乙醛脱氢酶和视网膜脱氢酶2显着下调，这表明长期暴露与重金属污染环境不同。紧急接触重金属污染可能会显着抑制牡蛎的应激和免疫反应系统。此外，福尔明同源 2 结构域含有蛋白质 (FH2)。唯一能够直接将肌动蛋白单体成核成无支链丝状聚合物的蛋白质结构域，随后控制基因表达和染色质重塑复合物，在长期暴露于重金属污染的牡蛎鳃中也被检测到显着上调。这表明核活动调节对于牡蛎适应长期重金属污染的环境可能也很重要。 (C) 2014 Elsevier Ltd. 保留所有权利。
Bio-accumulation and bio-transmission of toxic metals and the toxicological responses of organisms exposed to toxic metals have been focused, due to heavy metal contaminations have critically threatened the ecosystem and food security. However, still few investigations focused on the responses of certain organisms exposed to the long term and severe heavy metal contamination in specific environments. In present investigation, the Hong Kong oyster, Crassostrea hongkongensis were obtained from 3 sites which were contaminated by different concentrations of heavy metals (such as zinc, copper, manganese and lead etc.), respectively. Heavy metal concentrations in the sea water samples collected from the 3 sites and the dissected tissues of the oysters with blue visceral mass were determinated to estimate the metal contamination levels in environments and the bio-accumulation ratios of the heavy metals in the different tissues of oysters. Moreover, Proteomic methods were employed to analyze the differentially expressed proteins in the gills of oysters exposed to long-term heavy metal contaminations. Results indicated that the Jiulong River estuary has been severely contaminated by Cu, Zn and slightly with Cr, Ni, Mn, etc, moreover, Zn and Cu were the major metals accumulated by oysters to phenomenally high concentrations (more than 3.0% of Zn and about 2.0% of Cu against what the dry weight of tissues were accumulated), and Cr, Ni, Mn, etc were also significantly accumulated. The differentially expressed proteins in the gills of oysters exposed to heavy metals participate in several cell processes, such as metal binding, transporting and saving, oxidative-reduction balance maintaining, stress response, signal transduction, etc. Significantly up-regulated expression (about 10 folds) of an important metal binding protein, metallothionein (MT) and granular cells was observed in the gills of oysters exposed to long-term and severely heavy-metal-contaminated estuary, it suggested that binding toxic metals with metallothionein-like proteins (MTLP) and storing toxic metals in metal-rich granules (MRG) with insoluble forms were the important strategies of oyster to detoxify the toxic metals and adapt to the high level of metal-contaminated environment. Most of the stress and immunity responsive proteins, such as heat shock proteins (HSP), extracellular superoxide dismutase (ECSOD) and cavortin, and the cellular redox reaction relative proteins such as 20G-Fe (II) oxygenase family oxidoreductase, aldehyde dehydrogenase and retinal dehydrogenase 2, were detected significantly down-regulated in the gills of oysters exposed to long term heavy metal contaminated environments, it indicated that long term exposure different from emergent exposure to heavy metal contamination may significantly suppress the stress and immunity response system of oysters. Moreover, Formin homology 2 domain containing protein (FH2). The only protein domain to directly nucleate actin monomers into unbranched filament polymers, by which will subsequently control gene expression and chromatin remodelling complexes, was also detected greatly up-regulated in the gills of oysters exposed to long-term heavy metal contaminations. It indicated that nuclear activity regulation may also be important for oyster to adapt to the long-term heavy-metal-contaminated environment. (C) 2014 Elsevier Ltd. All rights reserved.