第三章原核微生物細(xì)菌和古生菌

1、第3章 原核(yun h)生物：細(xì)菌和古生菌Procaryotes: The Bacteria and ArchaeaA Microbiology Course by Bo CHEN (e-mail: qqchen36)共四十五頁(yè)CONTENTSSurvey of Procaryotic Cell StructureBacterial External StructureBacterial Internal StructureBacterial Shapes, Arrangements, and SizesBacterial Identification and Classification

2、SystemsUnusual Procaryotic Groups共四十五頁(yè)SECTION 1 Survey of Procaryotic Cell Structure(原核細(xì)胞的結(jié)構(gòu)(jigu)概覽)共四十五頁(yè)Survey of procaryotic cell structure (a typical rod-shaped bacterium). General structure; Special structure10986754123中間體：1.增加(zngji)表面積；2.類似細(xì)胞器功能糖被儲(chǔ)藏(chcng)顆粒菌毛性毛鞭毛類核共四十五頁(yè)Survey of Procaryotic

3、Cell StructureProcaryotic cell (原核細(xì)胞)Appendages (附體)Cytoplasm (細(xì)胞質(zhì)) Cell envelope (細(xì)胞(xbo)包被)Flagella (鞭毛(binmo) Pili (性毛) Fimbriae (菌毛)Glycocalyx (糖被) Cell wall Cell membraneCell pool Granules (貯藏顆粒) Ribosomes Nucleoid (類核)/chromosomeCapsules (莢膜) Slime layers (粘液層)External structureInternal struct

4、ure共四十五頁(yè)SECTION 2 Bacterial External Structure (細(xì)菌的外部(wib)結(jié)構(gòu))共四十五頁(yè)2.1 APPENDAGES: CELL EXTENSIONS (附體：細(xì)胞(xbo)的延伸)Appendages (附體)Flagella (鞭毛(binmo) motility (運(yùn)動(dòng)性)Pili (性毛) DNA transfer (DNA轉(zhuǎn)移)Fimbriae (菌毛) adhesion (粘附)共四十五頁(yè)Flagella Bacterial Propellers(鞭毛(binmo) 細(xì)菌的螺旋槳)Flagellum: Latin, whip20 nm i

5、n diameter, 1-70 nm in lengthFunction: motility, or self-propulsion, to swim in aqueous habitatAll spirilla (螺旋菌), about half of the bacilli (桿菌(gnjn), and a small number of cocci (球菌) are flagellated共四十五頁(yè)Fig.4.2 Structure of flagella. (a) Electron micrograph of basal bodies and filaments (at arrows

6、) of bacterial flagella (66,000). (b) Details of the basal body in a gram-negative cell.Form of flagella鞭毛(binmo)絲鞭毛(binmo)鞘 (sheath)基體!共四十五頁(yè)Filament, a helical structure composed of proteins flagellin (鞭毛(binmo)絲, 由鞭毛蛋白構(gòu)成), 20 nm in diameter, 1-70 nm in length共四十五頁(yè)Fig.4.3 Electron micrographs depic

7、ting types of flagellar arrangementsTypes of flagella (三種(sn zhn)類型)1. Monotrichous (a. 單生)2. Lophotrichous (b. 單端叢生) Amphitrichous (c. 兩端叢生)3. Peritrichous (d. 周生)Note: 端生=極生 (polar flagella)Gr. hairy共四十五頁(yè)Motility (運(yùn)動(dòng)性)運(yùn)動(dòng)方式(fngsh)不同于鞭子的抽動(dòng)，而是360旋轉(zhuǎn) (rotation)Velocity: Pseudomonas aeruginosa (銅綠假單胞菌):

8、 polar, can swim 4.4 mm/min (2,000-fold the length of the bacterium) E. coli: peritrichous (周生), 1 mm/minFunction of flagella共四十五頁(yè)Fig.4.5 The operation of flagella and the mode of locomotion in bacetria with polar and peritrichous flagella. Direction of rotation:Counterclockwise: swim forward (run)

9、Clockwise: stop (tumble 翻滾(fngn)共四十五頁(yè)Motility Detectiona. Stab inoculation into a semisolid medium (半固體穿刺培養(yǎng))(a)(b)b. Hanging drop slide (懸滴法)Motile: the cell swims and progresses from one point to another; Nonmotile: the cell oscillates (振蕩) in the same space (Brownian movement).共四十五頁(yè)鞭毛(binmo)與趨向性Th

10、ey can detect and move in response to chemical and light signalsChemotaxis (趨化性) Positive: favorable chemical stimulus (nutrients, move forward) Negative: harmful chemical stimulus (move away)Phototaxis (趨光性) some photosynthetic bacteria共四十五頁(yè)Fig.4.9 Three bacteria in the process of conjugation (bact

11、erial mating 細(xì)菌接合(jih)作用).Pili (性毛)Sex pilusFound only on G-bacteriaFunction: DNA Transfer共四十五頁(yè)共四十五頁(yè)Fig.4.8 Form and function of bacetrial fimbriaeFunction: adhesion (粘附(zhn f) attachment)Relationship between Fimbriae and pathogenicity Gonococcus (淋球菌)侵染(qn rn)泌尿道 E. coli侵染腸道 Mutation and pathogenic

12、ityFimbriae (菌毛)(絨毛)共四十五頁(yè)2.2 THE CELL ENVELOPE (細(xì)胞(xbo)包被)123共四十五頁(yè)Glycocalyx (糖被) 糖被：是包裹在某些細(xì)菌(xjn)細(xì)胞壁外的一層膠狀物質(zhì) 多種名稱：多糖-多肽復(fù)合物，糖萼，糖被 兩類： 莢膜 (b)：結(jié)構(gòu)比較緊密，有固定形態(tài)，固定在壁上 粘液層 (a)：結(jié)構(gòu)比較松散，無(wú)固定形態(tài)，未固定在壁上共四十五頁(yè)不動(dòng)桿菌屬根瘤菌屬Capsule (莢膜)* the cell proper: the proper cell 嚴(yán)格意義上的(真正的，本身(bnshn)的)細(xì)胞共四十五頁(yè) 光滑(gung hu)型菌落：S型，smoo

13、th type，mucoid (粘液樣的) ，有莢膜 粗糙型菌落：R型，rough type，noncoid ，無(wú)莢膜根據(jù)有無(wú)(yu w)莢膜，菌落分為2種類型：共四十五頁(yè)莢膜的功能(gngnng)保護(hù) (protection)： 極端環(huán)境下（e.g.干旱、貧瘠）防止水分和營(yíng)養(yǎng)丟失；防止噬菌體的吸附和裂解；防止宿主白細(xì)胞吞噬：有莢膜的肺炎鏈球菌有致病性，引起(ynq)肺炎，如發(fā)生突變，無(wú)莢膜的肺炎鏈球菌致病性大大下降營(yíng)養(yǎng)補(bǔ)充 (nutrient supplement)： 莢膜多糖、多肽粘附 (adhesion)： 定位作用，菌膠團(tuán)（莢膜包裹在細(xì)胞群上，e.g.動(dòng)膠菌屬Zoogloea）共四十五

14、頁(yè)Fig.4.13 Biofilm. Staphylococcus aureus (金葡) cells attached to a catheter (導(dǎo)尿管) by a slime secretion.共四十五頁(yè)Application of Capsules腸膜狀明串株菌 糖被中提取葡聚糖制備“代血漿”野油菜黃單胞菌 粘液(zhn y)層中提取胞外多糖 黃原膠新型粘著劑？共四十五頁(yè)Cell Wall (細(xì)胞壁)壁與墻的區(qū)別(qbi)共四十五頁(yè)Cell Wall (細(xì)胞壁)Location: the second layer of cell envelope, between glycocal

15、yx and cell membrane.Composition: mainly composed of peptidoglycan (肽聚糖), the unique component of eubacteria cell wall (注意(zh y)：真細(xì)菌特有，古細(xì)菌沒(méi)有).Function: keep the cell shape, provide osmotic (滲透壓) protection.共四十五頁(yè)1. Glycan chain (聚糖鏈)2. Tetrapeptide side chain (四肽側(cè)鏈)3. Peptide interbridge (肽間橋)(G)(M)P

16、eptidoglycan (肽聚糖)網(wǎng)絡(luò)狀大分子共四十五頁(yè)(N-乙酰氨基(nj)葡萄糖)(N-乙酰胞壁酸)Glycan chain (聚糖鏈)Lactic acid糖苷鍵共四十五頁(yè)Glycan chain (聚糖鏈)G： N-乙酰氨基葡萄糖M：N-乙酰胞壁酸聚糖鏈：每條鏈10-65個(gè)二糖單位 (-G-M-)金葡：只有(zhyu)9個(gè)二糖單位地衣芽胞桿菌：79個(gè)二糖單位共四十五頁(yè)S.aureus (G+)Peptide chain(G+)=O短肽鏈：包括(boku)四肽側(cè)鏈和肽間橋penicillin acting site共四十五頁(yè)P(yáng)eptide Chain (肽鏈)四肽側(cè)鏈：4個(gè)aa按L型與

17、D型交替方式連接，在金葡（G+）中為L(zhǎng)-Ala-D-Glu-L-Lys-D-Ala，D-型aa在細(xì)菌細(xì)胞壁之外很少出現(xiàn)肽間橋：金葡中為5個(gè)Gly，不同細(xì)菌可能(knng)肽聚糖不同（已知超過(guò)100種，肽聚糖多樣性），主要是肽間橋組成aa不同。青霉素：作用于肽間橋Gly與四肽側(cè)鏈D-Ala之間（不同抗生素作用效果不同，肽間橋組成多樣性造成，見(jiàn)上圖）共四十五頁(yè)Lactic acid糖苷鍵Tetrapeptide side chain (四肽側(cè)鏈,G)N-乙酰胞壁酸乙酰氨基(nj)葡萄糖內(nèi)消旋二氨基(nj)庚二酸, G-獨(dú)有G四肽側(cè)鏈與G+組成有所不同共四十五頁(yè)m-DAP (內(nèi)消旋二氨基(nj)庚二

18、酸,G)與Lysine (賴氨酸,G+)共四十五頁(yè)P(yáng)eptidoglycan (肽聚糖)網(wǎng)絡(luò)狀大分子復(fù)合物 由3部分(b fen)組成：1. Glycan chain (聚糖鏈)2. Tetrapeptide side chain (四肽側(cè)鏈)3. Peptide interbridge (肽間橋)單層多層: 枯草桿菌20層共四十五頁(yè)肽聚糖網(wǎng)狀結(jié)構(gòu)的特點(diǎn)(tdin)Rigidity 剛性：決定和保持細(xì)胞的形狀I(lǐng)ntegrity 完整性：保護(hù)細(xì)胞不致因滲透壓破裂Meshwork 網(wǎng)狀結(jié)構(gòu)：物質(zhì)交換 (營(yíng)養(yǎng)吸收(xshu)、廢物排出)*交聯(lián)度：決定網(wǎng)孔大小與結(jié)構(gòu)強(qiáng)度 (交聯(lián)度越大，網(wǎng)孔越小，結(jié)構(gòu)強(qiáng)

19、度越大)共四十五頁(yè)Mechanisms of Antibiotics and Lysozymes共四十五頁(yè)(N-乙酰氨基(nj)葡萄糖)(N-乙酰胞壁酸)Lysozyme (溶菌酶)糖苷鍵Lysozyme- sensitive bond, lysozyme hydrolyzing site共四十五頁(yè)P(yáng)enicillin target: binds and blocks peptidaseC=OS.aureus (G+)Penicillin (青霉素)共四十五頁(yè)The mode of action of penicillins on the bacterial cell wallPenicillins bind and block peptidases catalyzing the cross-link of glycan molecules, thereby interrupting the completion of the cell wall.“散架(sn ji)”共四十五