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MicroorganismsandMicrobiologyChapter1

MicroorganismsandMicrobiolog1Chapteroutline1.1Whatisamicrobe?1.2TheimportanceofMicrobiology1.3Microbesinourlives1.4Thehistoryofmicrobiology1.5ImportanteventsinthedevelopmentofmicrobiologyChapteroutline1.1Whatisam2ConceptsMicroorganismsareresponsibleformanyofthechangesobservedinorganicandinorganicmatter(e.g.,fermentationandthecarbon,nitrogenandsulfurcyclesthatoccurredinnature.Thedevelopmentofmicrobiologyasascientificdisciplinehasdependedontheavailabilityofthemicroscopeandtheabilitytoisolateandgrowpureculturesofmicroorganisms.Microbiologyisalargediscipline,whichhasagreatimpactonotherareasofbiologyandgeneralhumanwelfareConceptsMicroorganismsareres3Thewordmicrobe(microorganism)isusedtodescribeanorganismthatissosmallthatcannotbeseenwithouttheuseofamicroscope.Viruses,bacteria,fungi,protozoaandsomealgaeareallincludedinthiscategory.1.1Whatisamicrobe?Thewordmicrobe(microorganis4Ourworldispopulatedbyinvisiblecreaturestoosmalltobeseenwiththeunaidedeye.Theselifeforms,themicrobesormicroorganisms,maybeseenonlybymagnifyingtheirimagewithamicroscope.Ourworldispopulatedby5

MicrobialworldOrganisms

(living)Infectiousagents

(non-living)Prokaryotes(unicellular)eukaryotesvirusesviroidsprionsEubacteriaArchaeaAlgae(unicellularormulticellular)Fungi(unicellularormulticellular)Protozoa(unicellular)Other(multicellularorganisms)MicrobialworldOrganisms(li6Mostofthebacteria,protozoa,andfungiaresingle-celledmicroorganisms,andeventhemulticelledmicrobesdonothaveagreatrangeofcelltypes.Virusesarenotevencells,justgeneticmaterialsurroundedbyaproteincoatandincapableofindependentexistence.Thesizeandcelltypeofmicrobes

Mostofthebacteria,protozoa7ThesizeandcelltypeofmicrobesThesizeandcelltypeofmicr8Microbesimpingeonallaspectsoflife,justafewofthesearelistedbelow:TheenvironmentMedicineFoodBiotechnologyResearch1.2TheimportanceofmicrobiologyMicrobesimpingeonallaspect9TheenvironmentMedicineFoodBiotechnologyResearchPressheretocontinueTheenvironmentPressheretoc10

Microbesareresponsibleforthegeochemicalcycles.Theyarefoundinassociationwithplantsinsymbioticrelationships.Somemicrobesaredevastatingplantpathogens,butothersmayactasbiologicalcontrolagentsagainstdiseases.Microbesareresponsiblefor11Thedisease-causingabilityofsomemicrobesiswellknown.However,microorganismshavealsoprovideduswiththemeansoftheircontrolintheformofantibioticsandothermedicallyimportantdrugs.Thedisease-causingabilityof12Microbeshavebeenusedtoproducefood,frombrewingandwinemaking,throughcheeseproductionandbreadmaking,tothemanufactureofsoysauce.Butmicrobesarealsoresponsibleforfoodspoilage.Microbeshavebeenusedtopro13Traditionallymicrobeshavebeenusedtosynthesizeimportantchemicals.Theadventofgeneticengineeringtechniqueshasledtothecloningofpolypeptidesintomicrobes.Traditionallymicrobeshavebe14Microbeshavebeenusedasmodelorganismsfortheinvestigationofbiochemicalandgeneticalprocesses.Millionsofcopiesofthesamesinglecellcanbeproducedveryquicklyandgiveplentyofhomogeneousexperimentalmaterial.Mostpeoplehavenoethicalobjectionstoexperimentswiththesemicroorganisms.Microbeshavebeenusedasmod151.3Microbesinourlives

MicroorganismsasDiseaseAgentsMicroorganismsandAgricultureMicroorganismsandtheFoodIndustryMicroorganisms,Energy,andtheEnvironmentMicroorganismsandtheFuture1.3MicrobesinourlivesMicr16

BranchesofMicrobiologyBacteriologyProtozoologyParasitologyMicrobialMorphologyMycologyVirologyPhycologyorAlgologyMicrobialphysiologyMicrobialtaxonomyMicrobialgeneticsMolecularbiologyMicrobialecologyBranchesofMicrobiologyBacte17ThefutureofmicrobiologyisbrightMicrobiologyisoneofthemostrewardingofprofessions,becauseitgivesitspractitionerstheopportunitytobeincontactwithalltheothernaturalscienceandthustocontributeinmanydifferentwaystothebettermentofhumanlife.Thefutureofmicrobiologyis181.4ThehistoryofmicrobiologyInthefieldofobservation,chancefavorsonlypreparedminds.LouisPasteur1.4Thehistoryofmicrobiolog19ThediscoveryofmicroorganismsThespontaneousgenerationconflictTherecognitionofmicrobialroleindiseaseThediscoveryofmicrobialeffectsonorganicandinorganicmatterThedevelopmentofmicrobiologyinthiscenturyThediscoveryofmicroor20ThediscoveryofmicroorganismsThefirstpersontoaccuratelyobserveanddescribemicroorganismsAntonyvanLeeuwenhock(1632-1723)Thediscoveryofmicroorganism21ThefirstpersontoobserveanddescribemicroorganismswastheamateurmicroscopistAntonyvanleeuwenhoekofDelft,Holland.Leeuwenhockmadehissimple,single-lensmicroscopewhichcouldamplifytheobjectbeingviewed50–300times.Between1673-1723,hewroteaseriesofletterstotheRoyalSocietyofLondondescribingthemicrobesheobservedfromthesamplesofrainwater,andhumammouth.Thefirstpersontoobservean22Leeuwenhoek’sdrawingsofbacteriafromthehumanmouth.Adrawingofoneofthemicroscopesshowingthelensa;mountingpinb;andfocusingscrewscandd.lensObjectbeingviewedadjustingscrewsLeeuwenhoek’sdrawingsofbact23Pasteur’scontributions:LouisPasteurworkinginhislaboratoryLouisPasteur(1822–1895)

Pasteur(1857)demonstratedthatlacticacidfermentationisduetotheactivityofmicro-organismsPasteur(1861)conflictoverspontaneousgeneration–birthofmicrobiologyasasciencePasteur(1881)developedanthraxvaccinePasteurizationPasteur’scontributions:Louis24

Spontaneousgeneration–thatlivingorganismscoulddevelopfromnonlivingordecomposingmatter.ThespontaneousgenerationconflictSpontaneousgeneration–t25Pasteur’sswanneckflasksusedinhisexperimentsonthespontaneousgenerationofmicroorganismsPasteur’sswanneckflasksuse26Conclusion:Microorganismsarenotspontaneouslygeneratedfrominanimatematter,butareproducedbyothermicroorganismsConclusion:27RobertKochinhislaboratoryTherecognitionofmicrobialroleindiseaseRobertKoch(1843–1910)RobertKochinhislaboratoryT28Koch’sdemonstrationofspecialorganismscausespecialdiseasesKoch’sdemonstrationofspecia29

Koch’spostulatesThemicroorganismsmustbepresentineverycaseofthediseasebutabsentfromhealthyorganisms.Thesuspectedmicroorganismsmustbeisolatedandgrowninapureculture.Thediseasemustresultwhentheisolatedmicroorganismsisinoculatedintoahealthyhost.ThesamemicroorganismsmustbeisolatedagainfromthediseasedhostKoch’spostulatesThemicroor30TheGoldenageofmicrobiology

Kochandpurecultures

FermentationandPasteurization

Germtheoryofdisease

VaccinationTheGoldenageofmicrobiology31ThediscoveryofmicrobialeffectsonorganicandinorganicmatterTheRussianmicrobiologistWinograskydiscoveredthatsoilbacteriacouldoxidizeiron,sulfurandammoniatoobtainenergy,andalsoisolatednitrogen–fixingbacteria.Beijerinckmadefundamentalcontributionstomicrobialecology.HeisolatedAzotobacterandRhizobium.Thediscoveryofmicrobialeff32AlexanderFleming(1881-1955)SirAlexanderFlemingdiscoveredtheantibioticpenicillin.Hehadtheinsighttorecognizethesignificanceoftheinhibitionofbacterialgrowthinthevicinityofafungalcontaminant.AlexanderFleming(1881-1955)S33DateMicrobiologicalHistory1676Leeuwenhoekdiscovers"animalcules"PasteurshowsthatlacticacidfermentationisduetoamicroorganismPasteurshowsthatmicroorganismsdonotarisebyspontaneousgeneration1867Listerpublisheshisworkonantisepticsurgery1869Miescherdiscoversnucleicacids1876-1877KochdemonstratesthatanthraxiscausedbyBacillusanthracisLaverandiscoversPlasmodium,thecauseofmalaria1881KochculturesbacteriaongelatinPasteurdevelopsanthraxvaccine1.5ImportanteventsinthedevelopmentofmicrobiologyDateMicrobiologica341884Koch'spostulatesfirstpublishedMetchnikoffdescribesphagocytosisGramstaindeveloped1887Petridish(plate)developedbyRichardPetriBeijerinckisolatesrootnodulebacteriaBeijerinckprovesthatavirusparticlecausesthetobaccomosaicdisease1921Flemingdiscoverslysozyme1923FirsteditionofBergey'sManual1928Griffithdiscoversbacterialtransformation1929FlemingdiscoverspenicillinRuskadevelopsfirsttransmissionelectronmicroscope1935Stanleycrystallizesthetobaccomosaicvirus1884Koch'spostulatesfi35AveryshowsthatDNAcarriesinformationduringtransformationWaksmandiscoversstreptomycinWatsonandCrickproposethedoublehelixstructureforDNA1961-1966Cohenetaluseplasmidvectorstoclonegenesinbacteria1980Developmentofthescanningtunnelingmicroscope1983-1984ThepolymerasechainreactiondevelopedbyMullis1990Firsthumangene-therapytestingbegunDiscoveryofThiomargaritanamibiensis,thelargestknownbacteriumEscherichiacoligenomesequencedDiscoverythatVibriocholeraehastwoseparatechromosomes微生物學(xué)【英文版】(全套課件499P)361.HowdidPasteur'sfamousexperimentdefeatthetheoryofspontaneousgeneration?2.HowcanKoch'spostulatesprovecauseandeffectinadisease?3.Whowasthefirstpersontousesolidculturemediainmicrobiology?Whatadvantagesdosolidmediaofferforthecultureofmicroorganisms?REVIEWQUESTIONS:1.HowdidPasteur'sfamous374.Whatistheenrichmentculturetechniqueandwhywasitausefulnewmethodinmicrobiology?5.WhenandhowAlexanderFlemingdiscoveredantibiotics?4.Whatistheenrichment381.Pasteur'sexperimentsonspontaneousgenerationwereofenormousimportancefortheadvanceofmicrobiology,havinganimpactonthemethodologyofmicrobiology,ideason(heoriginoflife,andthepreservationoffood,tonamejustafew.Explainbrieflyhowtheimpactofhisexperimentswasfeltoneachofthetopicslisted.APPLICATIONQUESTIONS:

1.Pasteur'sexperimentsonsp392.DescribethevariouslinesofproofRobertKochusedtodefinitivelyassociatethebacteriumMycobacteriumtuberculosiswiththediseasetuberculosis.Howwouldhisproofhavebeenflawedifanyofthetoolshedevelopedforstudyingbacterialdiseaseshadnotbeenavailableforhisstudyoftuberculosis?

2.Describethevariouslines40RonaldM.AtlasCliffordRenkPrinciplesofMicrobiology.沈萍1999.微生物學(xué)

高等教育出版社。J。尼克林著林雅蘭等譯。科學(xué)出版社。周德慶2002.微生物學(xué)教程

第二版。高等教育出版社。李阜棣

胡正嘉.2000微生物學(xué)。

第五版。中國(guó)農(nóng)業(yè)出版社。趙斌何紹江.2002微生物學(xué)實(shí)驗(yàn)?？茖W(xué)出版社。Johnson.case.LaboratoryExperimentsinMicrobiology.JohnP.HarleyLansingM.PrescottMicrobiology3thEdition.Lansing,M.Prescott;John,P.Harley;andDonald,A.Klein.2002.Microbiology,5thed.McGraw-Hill.GerardJ.Tortora;BardellR.Funke;ChristineL.1998.Case.MicrobiologyAnIntroduction,6th.Benjamin/Cummings.Michael,T.Madigan;John,M.Martinko;andJack,Parker.2003.BrockBiologyofMicroorganisms,10th.Prentice-Hall.

References:RonaldM.AtlasCliffordRenk41Chapter2

CellBiologyChapter2CellBiology42

2.1Overviewofthestructureofmicrobialcells2.2Procaryoticcellwall2.3Cytoplasmicmembrane2.4Cellulargeneticinformation2.5Cytoplasmicmatrix–RibosomeandInclusions2.6Componentsexternaltothecellwall2.7Bacterialendospores2.8ComparisonoftheprokaryoticandeukaryoticcellChapteroutline2.1Overviewofthestructur43AprocaryoticcellAeucaryoticcell

OverviewofcellstructureAprocaryoticcellAeucaryotic443.TheircellwallalmostalwayscontainthecomplexpolysaccharidepeptidoglycanTheprokaryoticcell1.Theirgeneticmaterial(DNA)isnotenclosedwithinamembraneandtheylackothermembrane–boundedorganelles2.TheirDNAisnotassociatedwithhistidine4.Theyareverysmall!!3.Theircellwallalmostalw45Size:

Mostbacteriafallwithinarangefrom0.2to2.0umindiameterandfrom2to8uminlengthArod-shapedprokaryoteistypicallyabout1-5micrometers(μm)longandabout1μmwideMicroorganismsingeneralareverysmallandarecompletelyinvisibletothenakedeye.

Acyanobacterium8x50umSize:Mostbacteriafallwi46sizecomparisonofmicroorganismsVisibilityscaleMetersRelativesizeofMicrobesProkaryotesEukaryotesVirusesNakedeyeLightmicroscopeElectronmicroscopesizecomparisonofmicroorgani47acellincreasesinsize,itssurfacearea–to–volumeratiodecreasesSurfaceareaandvolumerelationshipsincellsacellincreasesinsize,its48spirallumShape:

Bacteriahaveafewbasicshapesspherical

coccusRod-shaped

bacillusspirallumShape:Bacteriahave49Thecellwallofthebacterialcellisacomplex,semi-rigidstructurethatisresponsibleforthecharacteristicshapeofthecell.Thecellwallsurroundstheunderlying,fragileplasma(cytoplasmic)membraneandprotectsitandinternalpartsofthecellfromadversechangesinthesurroundingenvironment.Almostallprokaryoteshavecellwalls.ProkaryoticcellwallThecellwallofthebacterial50Gram+Gram-SchematicdiagramofbacterialcellwallsBacteriacanbedividedintotwomajorgroups,calledgram-positiveandgram-negative.Theoriginaldistinctionbetweengram-positiveandgram-negativewasbasedonaspecialstainingprocedure,theGramstainGram+Gram-Schematicdiagramof51TheGram-positivecellwallhasapeptidoglycanlayerthatisrelativelythick(ca.40nm)andcomprisesapproximately90%ofthecellwall.ThecellwallsofmostGram-positiveeubacteriaalsohaveteichoicacids.Gram-positivecellwallTheGram-positivecellwallha52StructureoftheRepeatingUnitinPeptidoglycanTheseconstituentsareconnectedtoformarepeatingstructure,theglycantetrapeptide.Peptidoglycaniscomposedoftwosugarderivatives,N-acetylglucosamine(NAG)andN-acetylmuramicacid(NAM),andasmallgroupofaminoacidsconsistingofL-alanine,D-alanine,D-glutamicacid,andeitherlysineordiaminopimelicacid(DAP).StructureoftheRepeatingUni53微生物學(xué)【英文版】(全套課件499P)54PeptideandglycanunitsareconnectedinformationofthepeptidoglycansheetPeptideandglycanunitsarec55Gram-positiveBacteriafrequentlyhaveacidicpolysaccharidescalledteichoicacidsattachedtotheircellwall.Thetermteichoicacidsincludesallwall,membrane,orcapsularpolymerscontainingglycerophosphateorribitolphosphateresidues.ThesepolyalcoholsareconnectedbyphosphateestersandusuallyhaveothersugarsandD-alanineattached.

TeichoicacidsGram-positiveBacteriafrequen56Teichoicacidsandlipoteichoicacidsarearrangedintheoverallwallstructureofgram-positiveBacteria.TeichoicacidLipoteichoicacidTeichoicacidsandlipoteichoi57TheGram-negativecellwallisathinlayerattachedtoanoutermembranevialipoproteins.Theoutermembranecontainsphospholipidonitsinnersurfaceandlipopolysaccharide(LPS)onitsoutersurface.Thespacebetweentheoutermembraneandthecytoplasmicmembraneiscalledtheperiplasmicspace.TeichoicacidsdonotoccurinGram-negativebacterialcellwalls..

TheGram-negativecellwallis58微生物學(xué)【英文版】(全套課件499P)59OsidechainCorepolysaccharideLipidAChemicalstructureofLipopolysaccharideOsidechainCorepolysaccharid60MolecularmodelofE.colilipopolysaccharideMolecularmodelofE.colilipo61

Thebondsbetweenthecarbohydratesinpseudopeptidoglycanareβ1-3insteadof'β1-4asinpeptidoglycan.

CELLWALLSOFARCHAEBACTERIA

Thearchaebacteriadonotcontainpeptidoglycanintheircellwallsasoccursineubacteria.

N-acetylmuramicacidandD-aminoacidsarenotfoundinthecellwallsofarchaebacteria.(Differencesfromeubacteria)Thebondsbetweenthecarboh62Somearchaebacteriahavewallscomposedofpseudopeptidoglycan,whichresemblesthepeptidoglycanofeubacteriabutcontainsN-acetyltalosaminuronicacidinsteadofN-acetylmuramicacidandL.-aminoacidsinsteadoftheD-aminoacidsineubacterialcellwalls.Somearchaebacteriahavewall63ProtoplastFormation

Peptidoglycancanbedestroyedbycertainagentsforinstancelysozyme,thatbreaksthe1,4-glycosidicbondsbetweenN-acetylglucosamineandN-acetylmuramicacidinthemolecule.ProtoplastFormationPeptidogl64Thedifferencebetweengram-positiveandgram-negativebacteriaisduetothephysicalnatureoftheircellwalls.Ifthecellwallisremovedfromgram-positivebacteria,theybecomegramnegative.Thedifferencebetweengram-po65Thepeptidoglycanseemstoactasapermeabilitybarrierpreventinglossofcrystalviolet.Gram-negativepeptidoglycanisverythin,notashighlycross-linked,andhaslargerpores.Alcoholtreatmentalsomayextractenoughlipidfromthegramnegativewalltofurtherincreaseitsporosity.Forthesereasons,alcoholmorereadilyremovesthepurplecrystalviolet-iodinecomplexfromgram-negativebacteria.TheMechanismofGramStainingThepeptidoglycanseemstoact66

ProceduresofGramStainingProceduresofGramStaining67GrampositiveorGramnegative?GrampositiveorGramnegative68Morphologyofagram-positivebacterialcellMorphologyofagram-positive69StructureofcytoplasmicmembraneFunctionofcytoplasmicmembrane2.3CytoplasmicmembraneStructureofcytoplasmicmemb70A.Thetypicalcytoplasmicmembraneofprokaryoticandeukaryoticcellsisalipidbilayer,asillustratedhereshowingtheorientationsofthehydrophilic(tanspheres)andhydrophobic(black)endsofphospholipidsthatmakeupthisstructure.B.Colorizedelectronmicrographof'thecytoplasmicmembrane(CM)ofthebacteriumBacillussubtilisrevealsthecharacteristicrailroadtrackappearanceofthislipidbilayer.StructureofcytoplasmicmembraneItisatypicalUNITMEMBRANE!A.Thetypicalcytoplasmicmem71Thecytoplasmicmembrane,ahighlyselectivebarrier,isconstructedprincipallyoflipid,withinwhichcertainproteinsareembedded.Membranescontainbothlipidsandproteins,althoughtheexactproportionsoflipidandproteinvarywidely.Thecytoplasmicmembrane,ahi721.Permeabilitybarrier-preventsleakageandfunctionasgatewayfortransportofnutrientsintoandoutofthecell.2.Proteinanchor-siteofmanyproteinsinvolvedintransport,bioenergetics,andchemotaxis.3.Energyconservation-siteofgenerationanduseoftheprotonmotiveforce.

Functionofmembrane1.Permeabilitybarrier-preve73微生物學(xué)【英文版】(全套課件499P)74IntracellularmembranesystemBacteriacellsdon’tcontainmembrane-enclosedorganelles.However,bacteriamayhavespecializedinvaginationsofthecytoplasmicmembrane.Theirfunctionmaybetoprovidealargermembranesurfaceforgreatermetabolicactivity.IntracellularmembranesystemB75StructureofMesosomeMesosomemaybeinvolvedinwallformationduringdivisionorplayaroleinchromosomereplicationanddistributiontodaughtercells.ItmayalsobeinvolvedinsecretoryprocessesStructureofMesosomeMesosome762.4CellulargeneticinformationBacterialChromosomeSupercoilingandchromosomestructureChromosomalcopynumberPlasmids2.4Cellulargeneticinformati77Micrographofabacteriumshowingthenucleoidregion(green)withinthecytoplasmwherethebacterialchromosomeoccursMicrographofabacteriumshow78ThebacterialchromosomeisacircularDNAmacromoleculeexceptinStreptomyces

whereitislinearandRhodobacter

sphaffoides,whichhastwoseparatechromosomes.BacterialchromosomeThebacterialchromosomeisusuallyasinglecovalentlyclosedcircularmolecule.ThetermnucleoidisusedtodescribeaggregatedDNAintheprokaryoticcell.Thebacterialchromosomeisa79RangeofgenomesizesinvirousgroupsoforganismsandtheorganellesofeukaryaRangeofgenomesizesinvirou80Thebacterialchromosomeandsupercoiling:Thebacterialchromosomeands81ExampleofE.colicellThereareover

50supercoileddomainintheE.colichromosome.ThetotalamountofDNAisabout4600kb.IfthetotalDNAisopenedandlinearized,itwouldbe1mminlength.Thethecellisonlyabout2-3umlong.SotopackagethismuchDNAintothecellrequiresthattheDNAbehighlysupercoiled.ExampleofE.colicellTherea82ElectronmicrographofanisolatednucleoidreleasedfromE.coli.

Electronmicrographofanisol83Chromosomecopynumber

Bacteriathatreproduceasexuallyaretypicallyhaploidingeneticcomplement.Rapidlygrowingcellscontainmorethan

1copyofthechromosome,andonlywhencellgrowthhasceaseddoesthechromosomenumberapproachonepercell.ChromosomecopynumberBacteri84

Reproductionofabacterialcellrequiresthereplicationofthebacterialchromosome.ThemicrographshowsthesequenceofsynthesisofnewcircularloopsofdoublehelicalDNA.Bacterianormallyreproducebybinaryfission.Theinwardgrowthoftheseptumdividestheparentcelltoproducetwoequal-sizedprogenycells.

85Plasmidsdon’tcontainthegeneticinformationfortheessentialmetabolicactivitiesofthecell,buttheygenerallydocontaingeneticinformationforspecialfeatures.

PlasmidProkaryoticcellshavesmallextra-chromosomalgeneticelementscalledplasmids.Plasmidsdon’tcontainthegen86ResistantplasmidsColplasmidsConjugativeplasmidsMetabolicplasmidsMajortypesofplasmidsResistantplasmidsMajortype87

2.5Cytoplasmicmatrix–RibosomeandInclusions2.5Cytoplasmicmatrix–Ribo88Alleucaryoticandprocaryoticcellscontainribosomes,whichfunctionasthesitesofproteinsynthesis.Ribosomesarecomposedoftwosubunits

Procaryoticribosomesarecalled70Sribosomes,andthoseofeucaryoticcellsareknownas80SribosomesRibosomesTheletterSreferstoSvedbergunits,whichindicatetherelativerateofsedimentationduringultra-high-speedcentrifugationAlleucaryoticandprocaryotic89微生物學(xué)【英文版】(全套課件499P)90Withinthecytoplasmofprocaryotic(andeucaryotic)cellsareseveralkindsofreservedeposits,knownasinclusions.Someinclusionsarecommontoawidevarietyofbacteria,whereasothersarelimitedtoasmallnumberofspeciesandthereforeserveasabasisforidentification.Amongthemoreprominentbacterialinclusionsarethefollowing:Carbonstoragepolymers–PHBandglycogenPhosphatepolymersSulfurGranulesGasVacuolesINCLUSIONSWithinthecytoplasmofp91Polyhydroxybutyricacid(PHB)PHBisalipidlikecompound-oneofthemostcommoninclusionbodiesinprokaryoticorganisms.PHBiscommonlyfoundasastoragematerialanduniquetobacteria

Glycogenisastarchlikepolymerofglucosesubunits.GlycogengranulesareusuallysmallerthanPHBgranules.AVibriospeciesPolyhydroxybutyricacid(PHB)P92Manymicroorganismsaccumulategranulesofpolyphosphate,whicharelargereservesofinorganicphosphatesthatcanbeusedinthesynthesisofATPPolyphosphategranule

inabacterialcellAPseudomonasspeciesManymicroorganismsaccumulate93ThesulfurglobulesinsidethecellsofpurplesulfurbacteriumChromatiumbuderiSomebacteria,includingmanyphotosyntheticbacteria,accumulateelementalsulfurgranulesasaresultoftheirmetabolism.Thesulfurglobulesinsidethe94Gasvacuoles(blue)andstoragegranules(red)inthecyanobacteriumMicrocystisTheformationofgasvacuolesbyaquaticbacteriaprovidesamechanismforadjustingthebuoyancyofthecell.Manyaquaticcyanobacteriausetheirgasvacuolestomoveupanddowninthewatercolumn.Gasvacuoles(blue)Theformat952.6ComponentsexternaltothecellwallFlagellaFimbriaeandpiliCapsulesandslimelayers2.6Componentsexternaltothe96Motilityallowsthecelltoreachdifferentregionsofitsenvironment.Inthestruggleforsurvival,movementtoanewlocationmaymeanthedifferencebetweensurvivalanddeathofthecell.But,asinanyphysicalprocess,cellmovementiscloselytiedtoanenergyexpenditure,andthemovementofflagellaisnoexception.

Manyprokaryotesaremotile,andthisabilitytomoveindependentlyisusuallyduetoaspecialstructure,theflagellum(plural,flagella).Motilityallowsthecelltore97Fourbasictypesofflagellararrangementsa,monotrichousb,amphitrichousc,lophotrichousd,peritrichousFourbasictypesofflagellar98Flagellaarearrangeddifferentlyondifferentbacteria.Inpolarflagellationtheflagellaareattachedatoneorbothendsofthecell.Occasionallyatuft(group)offlagellamayariseatoneendofthecell,anarrangementcalledlophotrichous.Inperitrichousflagellationtheflagellaareinsertedatmanyplacesaroundthecellsurface(perimeans"around").Thetypeofflagellation,polarorperitrichous,isoftenusedasacharacteristicintheclassificationofbacteria.Flagellaarearrangeddifferen99TheflagellumofaGram-negativebacteriumTheflagellumofaGram-negati100Thefilamentofbacterialflagellaiscomposedofsubunitsofaproteincalledflagellin.

Thebaseoftheflagellumisdifferentinstructurefromthatofthefilament.Thereisawiderregionatthebaseoftheflagellumcalledthehook.Thehookconsistsofasingletypeofproteinandfunctionstoconnectthefilamenttothemotorportionoftheflagellum.

Thebasalbodyisanchoredinthecytoplasmicmembraneandcel