SUPEROXIDE DISMUTASE IN P.GINGIVALIS 381

P.Gingivalis 381 中的超氧化物歧化酶

• 批准号: 5210016
• 负责人: MICHAEL C LYNCH
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5210016
• 关键词: Bacteroides gingivalis; cytolysis; enzyme activity; fusion gene; gene expression; gene mutation; genetic regulatory element; iron metabolism; microorganism metabolism; mutant; oxidative stress; superoxide dismutase; virulence

Ubiquitous to most cells, enzyme systems have evolved for protection against oxidative stress. One system, which includes suproxide dismutase (SOD), acts to remove molecular oxygen and its univalent reductants, thereby protecting the cell from the harmful effects of these reactive oxygen species. Although an obligate anaerobe, the putative periodontopathogen Porphyromonas gingivalis exhibits considerable aerotolerance and it has been suggested that SOD may play a key role in this activity. In addition, SOD may act to counter host defense free oxygen radical activity. One recent study demonstrated that insertional inactivation of the sod gene in P. gingivalis ATCC 33277 resulted in a rapid loss of viability and cell Iysis. By allelic exchange mutagenesis, we constructed in the laboratory of Dr. Howard Kuramitsu, an isogenic P. gingivalis 381 mutant defective in the sod gene. As confirmed by Southern blot analysis, a significant portion of the sod gene has been deleted and replaced by a gene cassette conferring erythromycin resistance. Growth of the mutant under aerobic culture conditions resulted in cell Iysis, whereas wild type P. gingivalis 381 was not affected. Furthermore, cell viability of the mutant was diminished by greater than four orders of magnitude within three hours. These results support earlier finding that SOD is essential for aerobic tolerance in P. gingivalis. Ongoing studies to determine the role of this gene in evading host response mechanisms include neutrophil killing assays and implantation in animal model systems. In addition, the effects of the host cell environment on SOD expression is under investigation utilizing sod-reporter gene fusions. It is anticipated that these studies will yield novel information regarding the role of this gene in P.

酶系统普遍存在于大多数细胞中， 对抗氧化应激 一个系统，其中包括超氧化物歧化酶 (SOD)用于除去分子氧及其单价还原剂， 从而保护细胞免受这些活性物质的有害影响， 氧物种。 虽然是一种专性厌氧生物， 牙周病病原体牙龈卟啉单胞菌表现出相当大的 有氧耐力，并已提出，SOD可能发挥关键作用， 这个活动。 此外，SOD还可以对抗宿主的防御自由 氧自由基活性 最近的一项研究表明， 牙龈卟啉单胞菌ATCC 33277中sod基因的失活导致 快速丧失活力和细胞溶解。 通过等位基因交换诱变， 我们在霍华德仓光博士的实验室中构建了一个同基因的P. gingivalis 381突变体SOD基因缺陷。 经南方证实 印迹分析表明，SOD基因的显著部分已经缺失， 被赋予红霉素抗性的基因盒取代。 增长 突变体在需氧培养条件下导致细胞溶解， 而野生型牙龈卟啉单胞菌381不受影响。 此外，Cell 突变体的生存能力降低了四个以上的数量级， 三小时内的大小。 这些结果支持了早期的发现， SOD是牙龈卟啉单胞菌有氧耐受所必需的。 正在进行的研究 以确定该基因在逃避宿主反应机制中的作用 包括嗜中性粒细胞杀伤试验和动物模型植入 系统. 此外，宿主细胞环境对SOD的影响 利用SOD-报道基因融合体研究表达。 它 预计这些研究将产生新的信息， 该基因在P.