Accumulation of manganese in Neisseria gonorrhoeae correlates with resistance to oxidative killing by superoxide anion and is independent of superoxide dismutase activity
Accumulation of manganese in Neisseria gonorrhoeae correlates with resistance to oxidative killing by superoxide anion and is independent of superoxide dismutase activity
复制标题
DOI：
10.1046/j.1365-2958.2001.02460.x
复制
发表时间：
2001-06-01
影响因子：
3.6
通讯作者：
Jennings, MP
中科院分区：
文献类型：
--
作者：
Tseng, HJ;Srikhanta, Y;Jennings, MP
作为一种兼性需氧菌，具有高铁需求和高活性的需氧呼吸链，淋病奈瑟氏菌需要防御系统来应对有毒氧物质，如超氧化物。已经表明，补充100 μ M Mn（II）的培养基显著增强了该细菌对超氧化物的氧化杀伤的抗性。这种保护作用与N.淋病与以前的研究不同，这些研究表明，一些N。淋病可能不含超氧化物歧化酶，我们通过基因组分析鉴定了sodB基因，并通过Southern印迹法证实了其在所有菌株中的存在，但没有发现sodA或sodC的证据。一个sodB突变体表现出非常相似的敏感性，超氧化物杀伤的野生型细胞，表明铁依赖的SOD B没有一个主要的作用，在测试条件下的抗氧化杀伤。sodA基因的缺失表明锰依赖的抗氧化杀伤保护作用不依赖于锰依赖的SOD A。由于sodB突变体也表现出锰依赖性抗氧化杀伤，那么可以得出结论，这种抗性是独立的超氧化物歧化酶。抗氧化杀伤与锰（II）的细菌积累。我们假设，这种细菌使用Mn（II）作为化学猝灭剂，以类似的方式已经建立的过程中的植物乳杆菌。搜索推定的Mn（II）摄取系统确定了一个ABC盒型系统（MntABC）与周质结合蛋白（MntC）。一个mntC突变体被证明具有降低积累的Mn（II），也是非常容易氧化杀伤，即使在存在下添加的Mn（II）。综合起来，这些数据表明，N。淋病具有Mn（II）摄取系统，该系统对于抗氧化应激是关键的。
As a facultative aerobe with a high iron requirement and a highly active aerobic respiratory chain, Neisseria gonorrhoeae requires defence systems to respond to toxic oxygen species such as superoxide. It has been shown that supplementation of media with 100 muM Mn(II) considerably enhanced the resistance of this bacterium to oxidative killing by superoxide. This protection was not associated with the superoxide dismutase enzymes of N. gonorrhoeae. In contrast to previous studies, which suggested that some strains of N. gonorrhoeae might not contain a superoxide dismutase, we identified a sodB gene by genome analysis and confirmed its presence in all strains examined by Southern blotting, but found no evidence for sodA or sodC. A sodB mutant showed very similar susceptibility to superoxide killing to that of wild-type cells, indicating that the Fe-dependent SOD B did not have a major role in resistance to oxidative killing under the conditions tested. The absence of a sodA gene indicated that the Mn-dependent protection against oxidative killing was independent of Mn-dependent SOD A. As a sodB mutant also showed Mn-dependent resistance to oxidative killing, then it is concluded that this resistance is independent of superoxide dismutase enzymes. Resistance to oxidative killing was correlated with accumulation of Mn(II) by the bacterium. We hypothesize that this bacterium uses Mn(II) as a chemical quenching agent in a similar way to the already established process in Lactobacillus plantarum. A search for putative Mn(II) uptake systems identified an ABC cassette-type system (MntABC) with a periplasmic-binding protein (MntC). An mntC mutant was shown to have lowered accumulation of Mn(II) and was also highly susceptible to oxidative killing, even in the presence of added Mn(II). Taken together, these data show that N. gonorrhoeae possesses a Mn(II) uptake system that is critical for resistance to oxidative stress.