一切生物细胞内的基因都能保持其相对稳定性，但在一定内外因 素的影响下，遗传物质就可能发生变化，这种遗传物质的变化及其所 引起的表型改变称为突变（mutation）。广义的突变包括染色体畸变 （chromosome aberration）和基因突变（gene mutation）。前者将在以 后章节中介绍，本章着重讨论基因突变

基因（gene）是细胞内遗传物质的结构和功能单位，它以脱氧核 糖核酸（deoxyribonucleic acid，DNA）化学形式存在于染色体上。在 人类，基因通过生殖细胞从亲代向子代传递。早在 1944 年，Avery 等 用实验的方法就直接证明了 DNA 是生物的遗传物质。1953 年 Watson 和 Crick 在前人的工作基础上

一、基因组 二、基因组学 三、人类基因组计划

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)

Bacterial genomics Organisation Linear chromosomes Borrelia burgdorferi Streptomyces coelicolor Multiple chromosomes Vibrio cholerae Plasmids Borrelia burgdorferi

Bacteriophages ( phages ) are obligate intracellular parasites that multiply inside bacteria by making use of some or all of the host biosynthetic machinery . They are viruses that infect bacteria

The process of destroying all microbial forms. A sterile object is one free of all microbial forms, including bacterial spores

SIZE OF BACTERIA Unit for measurement : Micron or micrometer,μm: 1μm=10-3mm Size: Varies with kinds of bacteria, and also related to their age and external environment

What is critical care medicine？ Multidisciplinary healthcare specialty cares for patients with acute, life￾threatening illness or injury which including continuum of life support from the scene through discharge Coordinated care systems, analysis of treatment options, protocols, guidelines for the care of individual patients

Medical Microbiology and Parasitology Part I: Medical Microbiology Part II: Medical Parasitology