Nitrate/Nitrite Reducing System in Staphylococcus carnosus: Functional analysis of NirR and NreABC

肉葡萄球菌中硝酸盐/亚硝酸盐还原系统：NirR 和 NreABC 的功能分析

• 批准号: 5175368
• 负责人: Professor Dr. Friedrich Götz
• 金额: --
• 依托单位: Lehrstuhl für Mikrobielle Genetik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 1999
• 资助国家: 德国
• 起止时间: 1998-12-31 至 2003-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5175368?language=en
• 关键词: Nitrate; Nitrite; Reducing; System; Staphylococcus

Staphylococcus carnosus is traditionally used as a starter culture in the production of raw fermented sausages and dry-cured ham. We have shown that S. carnosus reduces nitrate to ammonia in a two-step mechanism. First, nitrate is reduced to nitrite by a dissimilatory nitrate reductase. Nitrite accumulates in the growth medium and is further reduced by a NADH-dependent nitrite reductase. Nitrite reduction only occurs in the absence of nitrate. Synthesis of both enzymes is induced by anaerobiosis and by the presence of nitrate and/or nitrite. At present, we have identified 26 genes which are involved in nitrate/nitrite reduction. Our aim is to elucidate the underlying regulatory mechanisms which ensure the hierarchical use of the electron acceptors oxygen, nitrate, and nitrite. NirR and NreABC are putative regulators of the nitrate/nitrite reducing system in S. carnosus and we are interested in their mode of action. Especially, we have NreB in view, since it might be involved in sensing and transmitting two different signals: (i) the presence of oxygen, and (ii) the presence of nitrate and/or nitrite. Understanding of the complex regulation of nitrate and nitrite reduction in S. carnosus would be a tool for studying the bioenergetic aspects of the system.

肉葡萄球菌传统上用作生发酵香肠和干腌火腿生产中的发酵剂。我们证明了S.肉质菌以两步机制将硝酸盐还原成氨。首先，硝酸盐被异化硝酸盐还原酶还原为亚硝酸盐。亚硝酸盐在生长培养基中积累，并通过NADH依赖性亚硝酸盐还原酶进一步还原。亚硝酸盐还原仅在不存在硝酸盐的情况下发生。这两种酶的合成是由厌氧和硝酸盐和/或亚硝酸盐的存在诱导的。目前，我们已经确定了26个基因参与硝酸盐/亚硝酸盐还原。我们的目的是阐明潜在的监管机制，确保分层使用的电子受体氧，硝酸盐和亚硝酸盐。NirR和NreABC可能是S.我们感兴趣的是它们的作用方式。特别是，我们考虑了NreB，因为它可能参与感知和传递两种不同的信号：（i）氧气的存在，以及（ii）硝酸盐和/或亚硝酸盐的存在。对S. carnosus将成为研究该系统生物能量方面的工具。