Patra Sourav Kumar, Bag Prasanta Kumar, Ghosh Sanjay
Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019, India.
Appl Biochem Biotechnol. 2017 Jul;182(3):871-884. doi: 10.1007/s12010-016-2367-2. Epub 2016 Dec 20.
Vibrio cholerae, the causative agent of cholera, poses serious threats to humans worldwide. V. cholerae faces host inflammatory response and encounters nitrosative stress before establishing successful colonization. It is not clear how V. cholerae combats nitric oxide and reactive nitrogen species. In the present study, we used three clinical strains of V. cholerae and tested their nitrosative stress response pattern towards sodium nitroprusside (SNP) and S-Nitrosoglutathione (GSNO). Among them, V. cholerae, belonging to both O1 and O139 serotypes, showed moderate resistance to SNP and GSNO. However, a V. cholerae strain belonging to non O1 and non O139 showed sensitivity to SNP but resistance towards GSNO. Reduced glutathione and glutathione reductase play a significant role to combat nitrosative stress in V. cholerae. This is the first report where we show the presence of GSNO reductase activity in V. cholerae and that it plays an important role to detoxify S-Nitrosoglutathione. GSNO reductase activity of V. cholerae was regulated by posttranslational modification through S-nitrosylation under in vitro conditions which could be reversed by dithiothreitol (DTT). In addition, we show that biofilm formation remained unaffected under nitrosative stress in V. cholerae.
霍乱弧菌是霍乱的病原体,对全球人类构成严重威胁。霍乱弧菌在成功定殖之前会面临宿主的炎症反应并遭遇亚硝化应激。目前尚不清楚霍乱弧菌如何对抗一氧化氮和活性氮物质。在本研究中,我们使用了三株霍乱弧菌临床菌株,并测试了它们对硝普钠(SNP)和S-亚硝基谷胱甘肽(GSNO)的亚硝化应激反应模式。其中,属于O1和O139血清型的霍乱弧菌对SNP和GSNO表现出中等抗性。然而,一株属于非O1和非O139的霍乱弧菌菌株对SNP敏感,但对GSNO具有抗性。还原型谷胱甘肽和谷胱甘肽还原酶在霍乱弧菌对抗亚硝化应激中发挥着重要作用。这是我们首次报道霍乱弧菌中存在GSNO还原酶活性,并且它在解毒S-亚硝基谷胱甘肽中起重要作用。在体外条件下,霍乱弧菌的GSNO还原酶活性通过S-亚硝基化的翻译后修饰进行调节,二硫苏糖醇(DTT)可以逆转这种调节。此外,我们表明在亚硝化应激下霍乱弧菌的生物膜形成不受影响。