The Cytochrome bd Oxidase of Porphyromonas gingivalis Contributes to Oxidative Stress Resistance and Dioxygen Tolerance

Porphyromonas gingivalis is an etiologic agent of periodontal disease in humans. The disease is associated with the formation of a mixed oral biofilm which is exposed to oxygen and environmental stress, such as oxidative stress. To investigate possible roles for cytochrome bd oxidase in the growth and persistence of this anaerobic bacterium inside the oral biofilm, mutant strains deficient in cytochrome bd oxidase activity were characterized. This study demonstrated that the cytochrome bd oxidase of Porphyromonas gingivalis, encoded by cydAB, was able to catalyse O2 consumption and was involved in peroxide and superoxide resistance, and dioxygen tolerance.

牙龈卟啉单胞菌（Porphyromonas gingivalis）是人类牙周病的致病原。该疾病与混合口腔生物膜的形成相关，这类生物膜会暴露于氧气及氧化应激等环境胁迫之中。为探究细胞色素bd氧化酶（cytochrome bd oxidase）在该厌氧菌于口腔生物膜内的生长与存续中可能发挥的作用，研究人员对细胞色素bd氧化酶活性缺陷的突变菌株进行了表征分析。本研究证实，由cydAB基因编码的牙龈卟啉单胞菌细胞色素bd氧化酶能够催化氧气消耗，并参与过氧化物、超氧化物抗性以及耐氧性的维持。