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1IntroductiontoMicrobiology1.WhatistheuniquefeaturesofMicroorganisms?1.1Smallsize,SimplestructureAntoniVanLeeuwenhock:Thewordmicroorganismisusedtodescribeanorganismthatissosmallthat,normally,itcannotbeseenwithoutuseofmicroscopy.ThelivingorganismsofmicroscopicsizeMostmicroorganismsareunicellularSomeofthemarenon-cellularstructure1.2Highdiversityspecies.Bacteria(actinomyce,algae,cyanobacteria)archaeafungi(yeast,mold)protozoaviruse1.3Widelydistributedinvariousenvironmentwithlargenumberssoil.109CFU/gwaterairplants,animals,humanbodyextremeenvironment,e.g.hotsprings1.4Fastgrowing,easycultivationgenerationtime,min.-hr.1.5Easymutation2.Theplaceofmicroorganismsinthelivingworld2.1whittaker’sfivekingdomconcept(1969)KingdomplantaeKingdomanimaliaKingdomfungiKingdomprotistaKingdommoneraThisclassificationsystemwasbasedonnutrition,photosynthesis,absorptionandingestion.2.2Woese’sthreedomains(kingdoms)DomainbacteriaDomainArchaeaDomaineucarya3.ThescopeofmicrobiologyMicrobiologyisthestudyoflivingorganismsofmicroscopicsize,whichincludebacteria,fungi,algae,protozoaandviruses.Itisconcernedwiththeirmorphology,reproduction,physiology,metabolism,geneticsandclassification.Itincludesthestudyoftheirdistributionandfunctioninnature,theirrelationshiptoeachotherandtootherlivingorganisms,theireffectsonhumanbeings,animalsandplants.4.Whydowestudymicrobiology?Microorganismsaffectthewell-beingofpeopleinagreatmanyways.Theyoccurinlargenumbersinmostnaturalenvironments.Someofthemarebeneficialandothersaredetrimental.4.1Thebeneficialaspects•InAgriculture•Microbialfertilizer•Biologicalcontrol2•SCP•Microbialenergy:methanegasforruralconsumption•Infoodproduction•yogurt,cheese,wine(alcoholfermentation)•foodingredients•Inenvironmentprotection•treatmentofwastematerials•todecomposematerials:pesticides,herbicides•InBiochemicalindustry•Antibiotics•enzymes•Aminoacides•organicacids•inmedicine•Vaccine•Antibioticspenicillin•ThepotentialappliedareasofMicrobiology•GMORecombinantDNAtechnology•Microbialplastics•Microbialpesticides•MicrobiosensorM传感器•Microbialfuelcells微生物燃料电池•MicrobialDNAchip微生物DNA芯片•Exploitationofmicroorganismsinextremeenvironments4.2Thedetrimentalaspects•Causediseases:humanbeingsanimalsPlants•spoilfood•deterioratematerials:ironpipes,wood,clothObjectives:makefulluseandexploitationofthebeneficialaspects;avoidandcontrolthedetrimentalaspects3Chapter1TheMorphologyandFineStructureofMicroorganisms1.ProcaryoticMicroorganisms1.1FeaturesdistinquishingprocaryoticfromEucaryoticcellsfeatureProkaryoticcellsBacteria(archaea)Eucaryoticcells(fungi,protozoa,plant,animal)CellwallCellmembraneCytoplasmicstructuresMesosomeRibosomeMitochondriaChloroplastGolgistructureEndoplosmicreticulumnucleusPeptidoglycanascomponentGenerallydonotcontainsterol;containpartofrespiratoryand,insome,photosyntheticmachineryinvaginationPresent70SAbsentAbsentAbsentAbsentNotboundedbynuclearmembrane;onecircularchromosome,ChromosomedoesnotContainhistones;nomitoticdivirsionNucleolusabsentAbsenteofpeptidoglycanSterolspresent;donotcarryoutrespiratoryandphotosynthesisnonabsent80SpresentpresentpresentpresentBoundedbynuclearmembrane;MorethanonechromosomeChromosomeshavehistones;MitoticnucleardivisionNucleoluspresent1.2Bacteria1.2.1Thesize,shapeandarrangementofbacterialcell•sphiericalcocci,coccusum;diameterA:diplococciB:streptococciC:tetradsD:staphylococciE:Sarcinae•straightrods:widnthxLengthum,bacilli,bacillus,Lactobacillus•helicallycurvedrods:spirilla,spirillumwidthxLengthum(No.ofcurve)•filament:hyphae,hypha→myceliumdiameterofhyphaμmActinoinyces:streptomycesspecies△somearenotconstant,butpleomorphicshape1.2.2SimplestainingtechniqueThecolorationofbacterialcellbyapplyingasinglesolutionofstaintoafixedsmearistermedsimplestaining.Steps:•Smearbacterialcellsonaslide4•dryandfix•Thefixedsmearisfloodedwithadyesolutionforaspecifiedperiodoftime•WashoffwithH2Oanddrytheclide•examethesize.Shapeandarrangementofbacterialcellsundermicroscope1.2.3Thestructuresandfunctionsofbacterialcells1.2.3.1StructuresexternaltothecellwallA.Flagella,FlagellumBacterialflagellaarehairlike,helicalappendagesthatprotrudethroughthecellwallandareresponsibleforswimmingmotility.•chemicalcomposition:proteinsubunits:flagellinLocation:polar:atoneorbothendsofthebacteriumLateral:alonethesidesofthebacterium•function:swimmingmotility•glidingmotility:somebacteriaaremotilewhentheyareincontactwithasolidsurface.Astheyglidetheyexhibitasinuous,flexingmotion.Thiskindofmovementiscomparativelyslow,onlyafewumpersecond.•Bacterialchemotaxismany,perhapsmost,bacteriaarecapableofdirectedswimmingtowardorawayfromvariouschemicalcompounds—aphemomenoncalledbacterialchemotaxis•Bacterialphototaxisphototrophicbacteriamovetowardsincreasinglightintensities.•Pili,pilus(fimbriae)Piliarenonhelical,filamentousappendagesthatarethinner,shorter,andmorenumerousthanflagella.ThewellknownistheFpilus(orsexpilus),itservesastheportofentryofgeneticmaterialduringbacterialmating.B.Capsules•Somebacterialcellsaresurroundedbyaviscoussubstanceformingacoveringlayerorenvelopearoundthecellwall.Ifthislaye