Cellular response against different heavy metal stress differs with the metal. Arsenic and chromium are heavy metals and toxic to living systems. The concentration of these metals in seawater is very low. However, due to their solubility in nature, they actively enter cells via various transport mechanisms and cause damage to the cells. Brevibacterium casei #NIOSBA88, a marine-derived, gram-positive isolate was multi-metal tolerant. Proteomic analysis of this isolate in response to arsenic and chromium resulted in the identification of total 2549 proteins, out of which 880 proteins were found to be commonly expressed at 750 mgL-1 arsenic and 100 mgL-1 chromium and in absence of both the metals. In contrast, 533, 212, and 270 proteins were found to be unique in the absence of any metal, 750 mgL-1 of arsenic and 100 mgL-1 of chromium respectively. Proteins such as antibiotic biosynthesis monooxygenase, ArsR family transcriptional regulator, cytochrome C oxidase subunit II, and thioredoxin reductase were exclusively expressed only in response to arsenic and chromium. Other proteins like superoxide dismutase, lipid hydroperoxide reductase, and thioredoxin-disulfide reductase were found to be upregulated in response to both the metals. Most of the proteins involved in the normal cell functioning were found to be downregulated. Major metabolic functions affected include amino acid metabolism, carbohydrate metabolism, translation, and energy metabolism. Peptide mass fingerprinting of Brevibacterium casei #NIOSBA88 exposed to arsenic and chromium respectively revealed the deleterious effect of these metals on the bacterium and its strategy to overcome the stress.

中文翻译：

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干酪短杆菌 #NIOSBA88 对砷和铬的细胞反应——一种蛋白质组学方法

细胞对不同重金属应激的反应因金属而异。砷和铬是重金属，对生命系统有毒。这些金属在海水中的浓度非常低。然而，由于它们在自然界中的溶解性，它们通过各种运输机制主动进入细胞并对细胞造成损害。干酪短杆菌 #NIOSBA88，一种源自海洋的革兰氏阳性分离株，具有多金属耐受性。对该分离物响应砷和铬的蛋白质组学分析导致​​鉴定出总共 2549 种蛋白质，其中 880 种蛋白质被发现通常在 750 mgL-1 砷和 100 mgL-1 铬且不存在这两种金属的情况下表达. 相比之下，发现 533、212 和 270 种蛋白质在没有任何金属的情况下是独特的，分别为 750 mgL-1 的砷和 100 mgL-1 的铬。抗生素生物合成单加氧酶、ArsR 家族转录调节剂、细胞色素 C 氧化酶亚基 II 和硫氧还蛋白还原酶等蛋白质仅在响应砷和铬时才表达。发现其他蛋白质如超氧化物歧化酶、脂质氢过氧化物还原酶和硫氧还蛋白二硫化物还原酶响应这两种金属而上调。发现参与正常细胞功能的大多数蛋白质被下调。受影响的主要代谢功能包括氨基酸代谢、碳水化合物代谢、翻译和能量代谢。分别暴露于砷和铬的干酪短杆菌 #NIOSBA88 的肽质量指纹图谱揭示了这些金属对细菌的有害影响及其克服压力的策略。