醫(yī)學(xué)微生物學(xué)英文版教學(xué)課件：第1章 Basic CharactersofBacteria

1、BacteriologyBasic Characters of BacteriaChapter 1Morphology and Structure of Bacteria Section 1 I . Size and Shape of bacteria Size of bacteria Measure unit - m (micrometer)炭疽芽胞桿菌 3-10 m大中大腸埃希菌 2-3 m小布魯菌 0.6-1.5 mShape of bacteria diplococcus ; streptococcus; staphylococcus; tetrads;sarcina streptob

2、acillus; coccobacillus; mycobacterium; bifidobacterium vibrio ; spirillum ; helicobacterium ; Coccus Bacillus Spiral bacterium 淋球菌鏈 球 菌 葡萄球菌四聯(lián)球菌八疊球菌大腸桿菌 核梭桿菌炭疽桿菌雙歧桿菌炭疽桿菌結(jié)核桿菌大腸桿菌幽門螺桿菌霍亂弧菌 Structure of Bacteria Structure of BacteriaPlasmid cell wall Elementary structure cell membrane cytoplasm nucleoi

3、d capsule Special structure flagellum (flagella) pilus (pili) spore Elementary structureCell Wall1. structure & chemical composition peptidoglycan（mucopeptide） 1)polysaccharide backbone N-acetylglucosamine (G) and N-acetylmuramic acid (M) linked alternately in a chain . 2) tetrapeptide side chain G+

4、 : ala-glu-lys-ala link muramic acid , G- : ala-glu-DAP-ala 3) pentapeptide bridge G+ 【L-glycine】5 lysozymeMMGGMMMMGGpenicillinMMMGGStructure of peptidoglycan of G+ bacteriaGGGGMMalaalaglugluDAPDAPalaalaStructure of peptidoglycan of G- bacteriaSpecial components of G+ cell wall 1. teichoic acids: wa

5、ll teichoic acid membrane teichoic acid （lipoteichoic acid, LTA） function : 1) the major surface antigens of the gram-positive bacteria 2) associated with pathogenicity (adhesion) 2. protein: SPA, M-protein Special components of G- cell wall 1.lipopolysaccharide(LPS) 1）lipid A -endotoxin , non-genus

6、 specific 2）core polysaccharide 3）specific polysaccharide “O”Ag2.Outer membrane protein : exchange ； receptor (sex pili ,phage); porin3.Lipoprotein 4.periplasmic space outer membraneThe Function of Cell Wall 1) protection 2) keep the constant shape 3) antigenicity 4) exchange materialL-Forms of Bact

7、eria cell wall deficient form 1)Morphology: highly pleomorphic; G- fried egg colony reversion G+-protoplasts G- -spheroplasts 2)Media : high osmotic ; 3)Pathogenicity : chronic infections; resistant to antibiotic treatment. cell membrane mesosome invagination vesicular membrane increase membrane are

8、a mesosomemesosomemesosome ribosome 70S (30S+50S) RNA(66%), protein(34%) rRNA-23S, 16S, 5S antibiotic target protein synthesizecytoplasm ribosome plasmid extra-chromosomal genetic material circle double chains DNA replicated independently carry genetic information control some functions of bacteria

9、factor F -control sex pilus factor R-control drug resistance col faction -control E.col. to produce bacteriocin. plasmid Cytoplasmic granules reserve material metachromatic granule Nucleoid DNA; histone-like protein, RNA Special Structure capsule slime layer outside the cell wall composed of polysac

10、charide or polypeptide produce: in animal body in media with serum or sugar 0.2 m capsule 0.2 m microcapsule肺炎雙球菌莢膜 莢膜 pneumococcus Function 1.antiphagocytosis 2. adherence 3.protected from the lytic action of complements, lysozyme and damage of antimicrobial agents. 4. anti-dry 5.antigenicity Flage

11、llaLong filamentous appendage Originate in the protoplasmic membrane Function 1. motility 2. antigenicity : “H”Ag 3. pathogenicity some bacteria (vibrio)霍亂弧菌假單胞菌傷寒桿菌螺旋體空腸彎曲菌 peritrichouspolar pili rigid surface appendage; G- 1. common pilus ： 100200/cell adhere to surface of bacteria associated with

12、 pathogenicity. 2. sex pilus ： 1-4/cell male bacteria with sex pilus transfer of genetic material（DNA） during bacteria conjugation F+-F-大腸桿菌普通菌毛大腸桿菌性菌毛普通菌毛普通菌毛 spore dormant form （resting forms ） 1) forming: inadequate nutrition 2)germination spore vegetative form activation initiation outgrowth肉毒桿菌芽胞炭疽桿菌芽胞肉毒桿菌芽胞破傷風(fēng)桿菌芽胞肉毒桿菌芽胞破傷風(fēng)桿菌芽胞Structure o