SUPEROXIDE DISMUTASE IN P.GINGIVALIS 381

P.Gingivalis 381 中的超氧化物歧化酶

• 批准号: 6238301
• 负责人: MICHAEL C LYNCH
• 金额: $ 6.57万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6238301
• 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.

大多数细胞中普遍存在酶系统，其进化是为了提供保护 对抗氧化应激。 一种系统，其中包括超氧化物歧化酶 (SOD)，起到去除分子氧及其单价还原剂的作用， 从而保护细胞免受这些反应性物质的有害影响 氧物种。 虽然是专性厌氧菌，但假定 牙周病原菌牙龈卟啉单胞菌表现出相当大的 SOD 可能在空气耐受性中发挥关键作用 这项活动。 此外，SOD 可能会免费对抗宿主防御 氧自由基活性。 最近的一项研究表明，插入 P. gingivalis ATCC 33277 中 sod 基因的失活导致 活力和细胞裂解迅速丧失。 通过等位基因交换诱变， 我们在 Howard Kuramitsu 博士的实验室构建了同基因 P. sod基因缺陷的gingivalis 381突变体。 据南航证实 印迹分析，sod 基因的很大一部分已被删除，并且 被赋予红霉素抗性的基因盒取代。 的成长 需氧培养条件下的突变体导致细胞裂解， 而野生型牙龈卟啉单胞菌381则不受影响。 此外，细胞 突变体的生存能力降低了四个数量级以上 三小时内的震级。 这些结果支持了之前的发现 SOD 对于牙龈卟啉单胞菌的有氧耐受至关重要。 正在进行的研究 确定该基因在逃避宿主反应机制中的作用 包括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 正在利用 sod-报告基因融合来研究表达。 它 预计这些研究将产生有关以下方面的新信息 该基因在 P 中的作用。