evolution and ecology of pathogens课件

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1、EvolutionandEcologyofPathogensMartinPolzCivil&EnvironmentalEngineeringMassachusettsInstituteofTechnologyOutlineEmergenceofpathogensGlobalimportanceofmicroorganismsWhatarepathogens?EvolutionofpathogenesisRe-emergenceofpathogensAntibioticresistanceCholeraCon

2、clusionsGerms,germseverywhereEvenonalittlepear,Germsgermsallaround,Evenonthedirtyground.Germs,germsmakemesick,Especiallyonacandystick.Germs,germsaresosmall,Evenonabouncyball.Candice'sGermPoemMicrobialcommunitiesdrivebiogeochemicalcycles…100humanactivities1

3、40biologicalfixation200denitrificationSOILATMOSPHEREOCEANS15biologicalfixation140denitrification1200internalcycling8000internalcycling10burial36riverflow<3fixationinlighteninggroundwaterExample:TheNitrogenCycle?humanactivities140biologicalfixation200denitr

4、ificationSOILATMOSPHEREOCEANS15biologicalfixation140denitrification1200internalcycling8000internalcycling?burial?riverflow<3fixationinlighteninggroundwaterNitrogenCycleWithoutMicrobesAllprocessesslow.Wouldlifebepossible?MicrobesBacteriaFungiProtistsViruses

5、BacteriaSmallEfficientBiochemicallydiverseFastgrowthMarineFreshwaterSedimentsSubsurfacesediments(0-3,000m)AnimalgutsCells/mlorgx106Totalcellsx10260.51.04,6000.34-2001-1051,0001.517038,0000.0004(Whitmanetal.1998)BacteriaareeverywhereGlobalbacterialbiomass(P

6、gofC)SoilandAquaticPlantsBacteriaSubsurfaceTerrestrialMarine5601.8262.222-215303MicrobialbiomassrivalsplantbiomassbuthashigherturnoverHowmanybacterialspeciesarethere?Wilson1988Totalnumberspecies:~1.4millionBacteria:~3,500Hammond1995Totalnumberspecies:~11m

7、illionBacteria:~10millionThegreatplatecountanomalymicrobialcommunityplatingDAPIstainedmarinewatersample<1%ofobservablebacteriagrowonstandardculturemediaGeneticdiversityTotalnucleicacids16SribosomalRNAgenesSequencesDiversityandevolutionaryrelationshipsIdent

8、ificationandquantificationMolecularapproach:greatdiversityofmicrobespathogensonlyaminorcomponentofmicrobialdiversityallowsunderstandingofevolutionofpathogenesisEmergenceofpathogensWhatisapathogen?Anevolutiona