《医学分子生物学 Molecular Biology in Medicine》课程PPT教学课件：第二章 核酸和蛋白质的结构与功能 Structures &functions ofnucleic acid &protein

1. DNA复制的基本特点 • 2. 原核生物DNA复制的特点 • 3.真核生物DNA复制的特点 4. DNA损伤与修复 • 5.逆转录 • 6.RNA的复制

• 分子生物学和医学分子生物学研 究的主要内容 • 分子生物学的历史 • 分子生物学在医学上的应用

Actinomyces A.israelii,A.naeslundii; Gram positive;sulfur granule; Related to decaytooth and peridentitis

Category Spore-forming:rod, Gram (+)--- Clostridium Nonspore-forming:see next slides

Gram-negative rods Curves or comma shaped Non-spore forming Highly motile-single polar flagella Associated with salt water Oxidase positive Facultative anaerobe Tolerate alkaline conditions to

Morphology & Identification Gram-negative non-spore forming rods. When motile, byperitrichous flagella. Primarily normal flora of gastrointestinal tract. E. coli>Klebsiella>Proteus>Enterobacter Free living, also transient colonizers of skin. Facultative anaerobes: mixed acid fermentation

Morphology & Identification Gram positive Facultative anaerobes Grape like-clusters Catalase positive Major components of normal flora

Manifestations of Infection: Signs and symptoms vary according to the site and severity of infection. Diagnosis requires a composite of information, including history, physical examination, radiographic findings, and laboratory data. Microbial Causes of Infection: Infections may be caused by bacteria, viruses, fungi, and parasites. The pathogen may be exogenous (acquired from environmental or animal sources or from other persons) or endogenous (from the normal flora)

Symbioses Commensalism: one partner benefits and the other is neither harmed nor benefited. Mutualism: both partners benefit. Parasitism: one partner benefits at the expense of the other