1章原核微生物080912

1、间体间体70s ribosome during translation ribosomes细菌细胞质中的内含物细菌细胞质中的内含物 prokaryotic cell (bacillus megaterium) electron micrograph of nucleoid dna 荧光显微镜荧光显微镜 特殊染色特殊染色荧光显微镜下的荚膜荧光显微镜下的荚膜 负染色负染色 bacteriumcapsule compositionstructural subunitsgram-positive bacteriabacillus anthracispolypeptide (polyglutamic a

2、cid)d-glutamic acidbacillus megateriumpolypeptide and polysaccharided-glutamic acid, amino sugars, sugarsstreptococcus mutanspolysaccharide(dextran) glucosestreptococcus pneumoniaepolysaccharidessugars, amino sugars, uronic acidsstreptococcus pyogenespolysaccharide (hyaluronic acid)n-acetyl-glucosam

3、ine and glucuronic acidgram-negative bacteriaacetobacter xylinumpolysaccharide(cellulose) glucoseescherichia colipolysaccharide (colonic acid)glucose, galactose, fucose glucuronic acidpseudomonas aeruginosapolysaccharidemannuronic acidazotobacter vinelandiipolysaccharideglucuronic acidagrobacterium

4、tumefacienspolysaccharide(glucan) glucose1、荚膜富含水分，可保护细胞免于干燥；、荚膜富含水分，可保护细胞免于干燥；2、能抵御吞噬细胞的吞噬；、能抵御吞噬细胞的吞噬；3、为主要表面抗原（、为主要表面抗原（k抗原），是有些病原菌的毒力因子；抗原），是有些病原菌的毒力因子；4、能保护菌体免受噬菌体和其他物质（溶菌酶和补体）的、能保护菌体免受噬菌体和其他物质（溶菌酶和补体）的侵害；侵害；5、是某些病原菌必须的粘附因子；、是某些病原菌必须的粘附因子；6、贮藏养料，是细胞外碳源和能源的储备物质、贮藏养料，是细胞外碳源和能源的储备物质 salmonella with

5、 a peritrichous arrangement of flagellatransmission electron micrograph of escherichia coli o157:h7单生鞭毛、丛生鞭毛、对生鞭毛、周生鞭毛单生鞭毛、丛生鞭毛、对生鞭毛、周生鞭毛bacterial flagellar arrangements有鞘的极生鞭毛鞭毛蛋白bacterial chemotaxisthe movement of a procaryotic flagellum results from rotation of its basal body and is similar to th

6、e movement of the shaft of an electric motor. bacterial cells can alter the speed and direction of rotation of flagella and thus are capable of various patterns of motility.electron micrograph of escherichia coli with piliadhesive tip of bacterial pili binding to host cell receptors bacteria alterin

7、g the adhesive tips of their piliby genetically altering the adhesive tips of their pili, certain bacteria are able to: 1) adhere to and colonize different cell types with different receptors, and 2) evade antibodies made against the previous pili. bacterial adherence with pilibacterial species wher

8、e observedtypical number on celldistribution on cell surfacefunctionescherichia coli (f or sex pilus)1-4uniformmediates dna transfer during conjugationescherichia coli (common pili or type 1 fimbriae )100-200uniformsurface adherence to epithelial cells of the gi tractneisseria gonorrhoeae100-200unif

9、ormsurface adherence to epithelial cells of the urogenital tractstreptococcus pyogenes (fimbriae plus the m-protein)?uniformadherence, resistance to phagocytosis; antigenic variabilitypseudomonas aeruginosa10-20polarsurface adherencesulfolobus acidocaldarius?attachment to sulfur particlesfimbriae ca

10、n be evenly distributed over the entire surface of the cell. they can number anywhere from a few to several hundred per cell. fimbriae allow a cell to adhere to surfaces including the surfaces of other cells. pili are usually longer than fimbriae and number only one or two per cell. pili function to join bacterial cells prior to the transfer of dn