第二章特殊结构.ppt

文档介绍：2 特殊结构
(1)荚膜capsule
某些细菌壁外存在着一层厚度不定的胶状物质。
成分
多糖
多肽
功能
非必需的
储藏养料,堆积代谢产物
保护作用
附着的物质基础
种类
菌胶团
意义
鉴定菌种
制成代血浆或Sephadex
污水处理
三次采油
微荚膜
荚膜
粘液层
某些细菌长在体表的长丝状、波曲的附属物。
鞭毛细丝:鞭毛球蛋白三条丝状亚基一条鞭毛细丝
钩形鞘:蛋白质亚基组成
基体:套管作用
(2)鞭毛flegellum
A motile E. coli propels itself from place to place by rotating its flagella. To move forward, the flagella rotate counterclockwise and anism "swims". But when flagellar rotation abruptly changes to clockwise, the bacterium "tumbles" in place and seems incapable of going anywhere. Then the bacterium begins swimming again in some new, random direction.
Swimming is more frequent as the bacterium approaches a chemoattractant (food). Tumbling, hence direction change, is more frequent as the bacterium moves away from the chemoattractant. So it is bination of swimming and tumbling that keeps them in areas of higher food concentrations.
鞭毛运动
原核生物与真核生物鞭毛差异
(3)芽孢Endospore
某些细菌在其生长发育后期,可在细胞内