《病原生物学（医学微生物学）》课程教学课件（英文）05_Bacteria Genetics

Section IFundaments of MicrobiologyMacrobial GeneticsSHIHEZI UNIVERSITY

Section I Fundaments of Microbiology Macrobial Genetics SHIHEZI UNIVERSITY

KEY TERMSPhenotypeVirulent pahgeGenotypeTemperate phage PlasmidLysogenyBaceriophageLysogenic bacteriaMutationGeneralized transductionRecombinantSpecialized transductionHfr strainTransformationTransductionConjugationLysogenic conversionSHIHEZI UNIVERSITY

KEY TERMS Phenotype Genotype Plasmid Baceriophage Mutation Recombinant Transformation Transduction Conjugation Lysogenic conversion Virulent pahge Temperate phage Lysogeny Lysogenic bacteria Generalized transduction Specialized transduction Hfr strain SHIHEZI UNIVERSITY

GeneticsGeneticsdefines and analyzes heredity, or constancy and changein the physiologic properties of organisms.GeneThe unit of heredity, a segment of DNA that carriesgenetic information for a specific biochemical orphysiologic property Phenotypethe collective structural and physiologic propertiesofacell or an organism Genotypethe sequence ofDNA within a gene or the organizationof genesSHIHEZIUNIVERSITY

Genetics  Genetics  defines and analyzes heredity, or constancy and change in the physiologic properties of organisms.  Gene  The unit of heredity, a segment of DNA that carries genetic information for a specific biochemical or physiologic property  Phenotype  the collective structural and physiologic properties of a cell or an organism  Genotype  the sequence of DNA within a gene or the organization of genes SHIHEZI UNIVERSITY

Genetic Material in BatceriaChromosome (genome Plasmid Bactriophage (phage)Insert sequence (IS) / transposon (TnSHIHEZI UNIVERSITY

Genetic Material in Batceria  Chromosome (genome)  Plasmid  Bactriophage (phage)  Insert sequence (IS) / transposon (Tn) SHIHEZI UNIVERSITY

bacteriumplasmidbacterialchromosomeProkaryotic Genome Double-stranded, circular DNA1um Size: 580kb (mycoplasma) ~ 4,600kb (E. coli)Semi-conservative replication Pathogenecity island The pathogenic determinant genes are oftenclustered together in the DNA and are referred to aspathogenicity islands+Quite largeup to at least 200 kb+Code for many virulence genes, including adhesinsinvasins, exotoxins, and mobilizationSHIHEZI UNIVERSITY

Prokaryotic Genome  Double-stranded, circular DNA  Size: 580kb (mycoplasma) ~ 4,600kb (E. coli)  Semi-conservative replication  Pathogenecity island  The pathogenic determinant genes are often clustered together in the DNA and are referred to as pathogenicity islands  Quite large— up to at least 200 kb  Code for many virulence genes, including adhesins, invasins, exotoxins, and mobilization SHIHEZI UNIVERSITY

Table 7-1. Comparison of genome sizes inseekaathndiruSize(kbp)OrganismProkaryotesArchae1660Methanococusjannaschi2180Archaeoglobus fulgidus580EubacteraMycoplasma genitalium820Mycoplasmapneumonide910Boreliaburgdoreri1040Chiamydia tachomatis1110Ricktsi prowazeki1140Treponema palldum1230Chiamyiapneumoniae1670Heliobacter pyori1830Hdemophilusinfuenzae2180Neiseria meningitidisserogroupA2270Nesria meningidisserogroup B4210Bacils sutlis4410Mycobacterum tuberculosis4640Escherichia oli48LambdaBacteriophageVariola186Viruses192Vaccinia229CytomegalovirusSHIHEZIUNIVERSITY

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Features of Plasmid Circular dsDNA<100kbGenetic infoGenes essential for bacterial growth are carriedon the chromosome, and plasmids carry genesassociated with specialized functionsRemoval / transferred Types: R, F, ViSHIHEZIUNIVERSITY

Features of Plasmid  Circular dsDNA <100kb  Genetic info Genes essential for bacterial growth are carried on the chromosome, and plasmids carry genes associated with specialized functions  Removal / transferred  Types: R, F, Vi . . . SHIHEZI UNIVERSITY

Table7-2.Examplesof metabolicactivitiesdetermined by plasmids.ActivityOrganismPseudomonaspeciesDegradation of camphortoluene,octane,salicylic acidBacilsstearothermophilusα-AmylaseAlcaligenes eutrophusUtilizationofHasoxidizabeenergy sourceEscherichia oliSucrose uptake andmetabolism,citrate uptakeKlesiellaspeciesNitrogen fixationStreptococcus (group N)Lactose utilization,galatose phosphotransferasesystem,citrate metabolismRhodosprilum rubrumSynthesis of photosyntheticpigmentFlavobacterium speciesNylon degradationSHIHEZIUNIVERSITY

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Plasmids Definition: Extrachromosomal geneticelements that are capable of autonomousreplication (replicon)Episome - a plasmid that can integrate intothe chromosomeSHIHEZIUNIVERSITY

Plasmids  Definition: Extrachromosomal genetic elements that are capable of autonomous replication (replicon)  Episome - a plasmid that can integrate into the chromosome SHIHEZI UNIVERSITY

Classification of Plasmids Transfer propertiesConjugativeNonconjugative Phenotypic effectsFertilityBacteriocinogenic plasmidResistance plasmid (R factorsSHIHEZI UNIVERSITY

Classification of Plasmids  Transfer properties Conjugative Nonconjugative  Phenotypic effects Fertility Bacteriocinogenic plasmid Resistance plasmid (R factors) SHIHEZI UNIVERSITY