GENETIC ANALYSIS OF POLYSACCHARIDE CAPSULE BIOSYNTHESIS AND REGULATION IN STREPTOCOCCUS PNEUMONIAE

肺炎链球菌（即肺炎球菌）是引起人类肺炎、脑膜炎和菌血症等侵袭性疾病的重要原因。许多人在鼻咽部无症状地携带这种有机体。然而，在一小部分情况下，这种生物会克服宿主的防御并侵入人体，导致危及生命的疾病。肺炎球菌的一个重要毒力因子是多糖囊，它在感染期间保护它免受宿主的免疫防御。直到最近，对参与产生这种抗原的肺炎球菌基因所知甚少。本项目旨在继续表征这些基因，并检查调节其表达的因素。这种调节机制可能非常重要，因为多糖胶囊水平的增加被认为是从携带到入侵过渡的关键一步。了解参与生物合成和调控胶囊生产的分子事件将提高我们对疾病过程的理解，并确定抗菌治疗的替代靶点。

Streptococcus pneumoniae (the pneumococcus) is an important cause of invasive diseases such as pneumonia, meningitis and bacteraemia in humans. Many people carry this organism in the nasopharynx asymptomatically. However, in a small proportion, the organism overcomes host defences and invades the body causing life-threatening disease. An essential virulence factor of the pneumococcus is the polysaccharide capsule which protects it from the immune defences of the host during an infection. Until recently, very little was known of the pneumococcal genes involved in production of this antigen. This project aims to continue characterization of these genes, and examination of the factors which regulate their expression. This regulatory mechanism may be very important, because production of increased levels of the polysaccharide capsule is believed to be an crucial step in the transition from carriage to invasion. An understanding of the molecular events involved in biosynthesis and regulation of capsule production will improve our understanding of the disease process and identify alternative targets for antimicrobial therapy.