Chaper3TheProkaryotes,Section1BacteriaSection2ActinomycetesSection3CyanobacteriaSection4ArchaeobacteriaSection5Otherprokaryotes,Size,Shape,andArrangementofBacterialCells,Mostbacteriafallwithinarangefrom0.2to2.0mindiameterandfrom2to8minlength.Theyhaveafewbasicshapes-sphericalcoccus(plural,cocci,meaningberries),rod-shapedbacillus(plural,bacilli,meaninglittlestaffs),andspiral.,Cm=10-2metermm=10-3meterm=10-6meternm=10-9meter,Bacteria,Thethousandsofspeciesofbacteriaaredifferentiatedbymanyfactors,includingmorphology(shape),chemicalcomposition(oftendetectedbystainingreactions),nutritionalrequirements,biochemicalactivities,andsourceofenergy(sunlightorchemicals).,Howtoidentifyanunknownbacterialspecies?,ArrangementofSphericalBacterialCells,diplococci,streptococci,tetracocci,sarcinae,staphylococci,Sphericalcoccus,TheMicrococcaceae,ThefamilyMicrococcaceaecontainsgram-positivecocci,0.5-2.5mindiameter,thatdivideinmorethanoneplanetoformregularorirregularclustersofcells.Allareaerobicorfacultativelyanaerobic.Thepeptidoglycandi-aminoacidisL-lysine.Thethreemostimportantgeneraare:,MicrococcusStaphylococcusStreptococcus,Micrococcusaerobic,gram-positive,catalasepositive,cellarrangesmainlyinpairs,tetrads,orirregularclusters,nonmotile.Theyareoftenyellow,orangeorredincolour,Staphylococcus-facultativelyanaerobic,gram-positive,usuallyformirregularclusters,nonmotile,catalasepositivebutoxidasenegative,fermentglucoseanaerobically.,staphylococci,staphylococci,Streptococcus-facultativelyanaerobicormicroaerophilic,catalasenegative,gram-positive,Cellarrangesinpairsorchains,usuallynonmotile,Afewspeciesareanaerobicratherthanfacultative.,Bacillidivideonlyacrosstheirshortaxis,sotherearefewergroupingsofbacillithanofcocci.,Rod-shapedbacteria,Diplobacilli,streptobacilli,Singlebacillus,Coccobacillus,ClostridiumbotulinusC.butyricumC.aceticumC.tetaniC.putrificum,Bacillussubtilis,B.MycoidesB.PastturiiB.megateriumB.ThuringiensisB.AnthracisB.BotulinusB.cereus,Spore-formingrodshapedbacteriaAlmostallSpore-formingbacteriaareGram+,ClostridiumAnaerobic,BacillusAerobic,Nonspore-formingrodshapedbacteriaMostnonsporeformingrodshapedbacteriaareGram-,Representatives:EscherchiacoliAlcaligenesProteusFlavobacteriaPseudomonasRhizobiumAzotobacter,Vibrio,SpirillumandSpirochete,Somebacteriaareshapedlikelongrodstwistedintospiralsorhelices;theyarecalledvibrios(likecommasorincompletespirals),spirillaifrigidandspirocheteswhenflexable.,vibrio,spirillum,spirochete,Actinomycetes,Actinomycetesarefilamentousbacteria.Theirmorphologyresemblesthatofthefilamentousfungi;however,thefilamentsofactinomycetesconsistofprocaryoticcells.Someactinomycetesresemblemoldsbyformingexternallycarriedasexualsporesforreproduction.,Filamentous,HighG+Ccontent,Gram-positive(6378%GC),Chainofconidiospores,Agarsurface,Substratemycelium,Aerialhyphae,Thecrosssectionofanactinomycetecolonyshowingthesubstratemyceliumandaerialmyceliumwithchainsofconidiospores,Varioustypesofspore-bearingstructuresonthestreptomyces,Representivegenera:StreptomycesNocardiaActinomycesMicromonosporaStreptosporangiumActinoplanesFrankia,Over500distinctantibioticsubstanceshavebeenshowntobeproducedbystreptomycete.Mostantibioticsareefficientagainstdifferentbacteria.Morethan50antibioticshavebeenusedinhumanandveterinarymedicine,agricultureandindustry,Antibiotics,Actinomycetes,Chainofconidiospores,Agarsurface,Substratemycelium,Aerialhyphae,Thecrosssectionofanactinomycetecolonyshowingthesubstratemyceliumandaerialmyceliumwithchainsofconidiospores,Varioustypesofspore-bearingstructuresonthestreptomyces,Streptomycesspores,calledconidia,arenotrelatedinanywaytotheendosporesofBacillusandClostridiumbecausethestreptomycetesporesareproducedsimplybytheformationofcross-wallsinthemultinucleatesporophoresfollowedbyseparationoftheindividualcellsdirectlyintospores.,EcologyandisolationofStreptomyces:AlkalineandneutralsoilsaremorefavorableforthedevelopmentofStreptomycesthanareacidsoils.Streptomycesrequirealowerwaterpotentialforgrowththanmanyothersoilbacteria.MediaoftenselectiveforStreptomycescontaintheusualassortmentofinorganicsalts,Themethodofaserialdilutionsforviablecounting,Thestreptonycetesarealargegroupoffilamentous,grampositivebacteriathatformsporesattheendofaerialfilaments.TheyhavethehighestGCpercentageintheDNAbasecompositionofanybacteriaknown.ManyclinicallyimportantantibioticshavecomefromStreptomycetesspecies,Concept:,Cyanobacteria,Thecyanobacteriahavetypicalprokaryoticcellstructuresandanormalgram-negativecellwall.Theyrangeindiameterfromabout110mandmaybeunicellularorformfilaments.Theyhavechlorophyllandcarryoutoxygen-producingphotosynthesis,muchasplantsandtheeukaryoticalgaedo.,FilamentousCyanobacterium,Anabaenasp.(SEMx5,000),Nonfilamentouscyanobacteria,Themorphologicaldiversityofthecyanobacteriaisconsiderable.Bothunicellularandfilamentousformsareknown,andconsiderablevariationwithinthesemorphologicaltypesoccurs.,Heterocystshaveintercellularconnectionswithadjacentvegetativecells,andthereismutualexchangeofmaterialsbetweenthesecells,withproductsofphotosynthesismovingfromvegetativecellstoheterocystsandproductsofnitrogenfixationmovingfromheterocyststovegetativecells.,PhotosynthesisNitrogenfixation,MainfunctionofCyanobacteria,Thenutritionofcyanobacteriaissimple.Vitaminsarenotrequired,andnitrateorammoniaisusedasnitrogensource.Nitrogen-fixingspeciesarecommon.Mostspeciestestedareobligatephototrophs,However,somecyanobacteriaareabletogrowinthedarkonorganiccompounds,usingtheorganicmaterialasbothcarbonandenergysource.,Physiologyofcyanobacteria:,Problems:Manycyanobacteriaproducepotentneurotoxins,andduringwaterbloomswhenmassiveaccumulationsofcyanobacteriamaydevelop,animalsingestingsuchwatermaysuccumbrapidly.,Aseptictechnique,Streakplate,Pourplate,Spreadplate,Archaeobacteriadifferfromeubacteriainanumberofotherways.Forexample,theircellwallsnevercontainpeptidoglycan,theyoftenliveinextremeenvironments,andtheycarryoutunusualmetabolicprocesses.,TheArchaebacteria,1.Themethanogens,strictanaerobesthatproducemethane(CH4)fromcarbondioxideandhydrogen.2.Extremehalophiles,whichrequirehighconcentrationsofsaltforsurvival.3.Thermoacidophiles,whichnormallygrowinhot,acidicenvironments.,Archaebacteriaincludethreegroups:,MethanogenicbacteriaarestrictanaerobesthatobtainenergybyconvertingC02,H2,formate,acetate,andothercompoundstoeithermethaneormethaneandC02.,C02+4H2CH4+2H2OCH3C00HC02+CH4,Sewagetreatmentplantsusethemethaneproducedtogenerateheatandelectricity,andmethanogenesismayeventuallyserveasamajorsourceofpollution-freeenergy.,extremelythermophilicbacteriaaregram-negative,aerobic,irregularlylobedsphericalbacteriawithatemperatureoptimumaround70-800CandapHoptimumof2to3.Theircellwallcontainslipoproteinandcarbohydratesbutlackspeptidoglycan.,Theirmostdistinctivecharacteristicistheirrequirementofahighconcentrationofsodiumchlorideforgrowth.Theyareaerobicchemoheterotrophswithrespiratorymetabolismandrequirecomplexnutrients,usuallyproteinsandaminoacids,forgrowth.,Extremehalophilicbacteria:,Otherprokaryotes,RickettsiaChlamydiaMycoplasmaBdellovirio,0.2-0.5mindiameter.obligateintracellularparasites.Themajorityofthemaregram-negativeandmultiplyonlywithinhostcells.Binaryfissionwithinhostcells.TheylacktheenzymaticcapabilitytoproducesufficientamountsofATPtosupporttheirreproduction.TheyobtaintheATPfromhostcells.Manyspeciesofthemcausediseaseinhumansandotheranimals.,Rickettsia,Theyareobligateintracellularparasites,unabletogeneratesufficientATPtosupporttheirreproduction.gram-negativeandcelldividesbybinaryfissionTheyChlamydiacausehumanrespiratoryandgenitourinarytractdisease,andinbirdstheycauserespiratorydisease.,Chlamydia,Diameter=0.1-0.25m.Theylackcellwall,areboundedbyasingletriple-layeredmembrane.Theyarethesmallestorganismscapableofself-reproduction.Thecolonyis“friedegg”appearance.Severalofthemcausediseasesinhumans.(pneumonia,respiratorytractdisease),Mycoplasma,Bdellovirio,SeeMovieforthedetailofinfectionandreproduction,Movie,Classificationofbacteria,MORPHOLOGICALCHARACTERISTICSDIFFERENTIALSTAININGNUCLEICACIDHYBRIDIZATIONGENETICRECOMBINATIONNUMERICALTAXONOMY,FungiPlantsAnimals,Protista,Prokaryotae,Five-kingdomsystemisacommonlyacceptedsystemofclassification,Archaebacteria,Eubacteria,Eukaryotes,Theta