《微生物學(xué)》課件 Microbiology Chapter 7

1、Chapter 7Microbial TaxonomyThe number of recorded organisms:1,500,000; microorganisms :150,000 200,000Taxonomy The science of classification, identification and nomenclature of organismsPhylogeny of microorganismThe study of the evolutionary history of microorganisms7.1 Evolutionary chronometersCert

2、ain cellular macromolecules can serve as evolutionary chronometers-actual measures of evolutionary change7.1.1 Choosing the right evolutionary chronometers1. The molecule should be universally distributed across the group chosen for study.2. The molecule must be functionally homologous in each organ

3、ism3. The sequence of the molecule must be conserved4. The size of the molecule must be consideredRibosomal RNA (rRNA) 40S60S18S28S5.8S5S2300bp4200bp160bp120bp80S rRNA30S50S16S23S5S1500bp2900bp120bp70S rRNA生物核糖體RNA亞基組成The Three-Domain SystemThe Three-Domain System7.1.2 Taxonomic Hierarchy域 domain 門(mén)

4、phylum 綱 class 目 order 科 family 屬 genus 種 species (1) Species DefinitionSpecies (sp.) In microbiology, a collection of strains which all share the same major properties but which differ in one or more significant properties from other collection of strains.Species DefinitionSpecies(sp.):Similar phen

5、otype, DNA homology 70% Tm5 Type strain :Bradyrhizobium japonicum ATCC 10324T。 Subspecies(ssp. subsp)Form生物型（biovar）化學(xué)型（chemovar）形態(tài)型（morphovar）致病型（pathovar）噬菌型（phagovar）血清型（serovar）7.1.3 International nomenclatureBacillus subtilis Chon 1872genus sp.Bacillus thuringiensis subsp. Galleriagenus sp. spp

6、.7.2 The methods of classification and identification(1) Traditional classificationMorphologyCulturePhysiologyBiochemistryEcology 從溫血?jiǎng)游锏哪c道分離細(xì)菌獲得純培養(yǎng)物革蘭氏反應(yīng)革蘭氏陰性革蘭氏陽(yáng)性桿狀非桿狀兼性專(zhuān)性好氧發(fā)酵乳糖，產(chǎn)酸產(chǎn)氣不發(fā)酵乳糖生化試驗(yàn)：（陽(yáng)性：吲哚，甲基紅，粘質(zhì)酸鹽陰性：檸檬酸，VP，H2S）大腸桿菌(2) Numerical Taxonomy(3) Molecular taxonomyG+C mol%DNA熱變性曲線（參照現(xiàn)代微生物學(xué)，劉志恒主

7、編，2002） 70 80 Tm 90 1001.5 14131.21.11.0解鏈溫度T 260nm光吸收值DNA-DNA hybridization16S rRNA sequence微生物純培養(yǎng)物提取DNA獲得總DNA，作為PCR擴(kuò)增模板加熱分開(kāi)兩條鏈加入特殊引物用DNA聚合酶進(jìn)行引物的延伸+重復(fù)上述步驟進(jìn)行多個(gè)PCR循環(huán)，以產(chǎn)生多個(gè)拷貝的16S rDNA用Sanger法測(cè)序電泳檢查擴(kuò)增產(chǎn)物應(yīng)用計(jì)算機(jī)程序進(jìn)行序列分析構(gòu)建系統(tǒng)發(fā)育樹(shù)DNA fingerprints -RAPDAFLP具體操作流程基因組DNATATAATGATCAATTGCATTATru1IEcoRIATGAAATCTTCGT

8、AACTATGAATTCGTTAAGCATTru1I接頭CAATTGEcoRI接頭酶切連接擴(kuò)增CATGATATru1I引物CCAATTCGTEcoRI引物GCTATACGTAACTATGAATTCGTTAAGTCCAG53AFLP作用原理AFLP標(biāo)記的聚丙烯酰胺電泳圖譜AFLP 指紋圖譜的UPGMA 相似性分析樹(shù)狀圖Polyphasic taxonomy 技術(shù)適用的分類(lèi)單元科屬種菌株技術(shù)方法限制性酶切片段長(zhǎng)度多態(tài)性(RFLP)低頻酶切片斷分析(LFFA, FFOE)核糖體DNA PCR擴(kuò)增酶切長(zhǎng)度多態(tài)性血清學(xué)方法DNA 擴(kuò)增 (AFLP, AP-PCR, rep-PCR, ARDRA)噬菌型多

9、位點(diǎn)酶電泳分析全細(xì)胞蛋白質(zhì)電泳圖譜DNA雜交 G + C mol %tDNA-PCR化學(xué)分類(lèi)標(biāo)記細(xì)胞脂肪酸組成(FAME)細(xì)胞壁結(jié)構(gòu)表型特征分析rRNA 序列分析DNA 探針DNA 序列分析Database and computer softwareDatabaseGenbank（NCBI）：info ncbi. nlm. nih. gov EMBL:fasta embl-heidelberg.de Software for drawing dendrogram or phylogenetic treeGCG(genetic computer Group package )GelcomparC

10、lustralXReferences Bergeys Manual of Determinative BacteriologyProvides identification schemes for identifying bacteria and archaeaMorphology, differential staining, biochemical tests Bergeys Manual of Systematic BacteriologyProvides phylogenetic information on bacteria and archaeaBased on rRNA sequ

11、encing Approved Lists of Bacterial NamesLists species of known prokaryotesBased on published articlesProkaryotes1. List the taxonomic hierarchy of classification.2. What is the three domain classification system ? Draw a simple dendrogram to show their phylogenetic relationship among the organisms.3. There are 50 strains isolated from the root nodules of peanut. These strains are slow-growing