16 英文版PowerPoint课件 Chapter 6 Microbial Metabolism.ppt

第1页：Chapter 6 Microbial

Chapter 6 Microbial Metabolism

• Energy Metabolism
• Special Metabolism in Microbes
• The Relationship between Catabolism and Anabolism
• Regulation of Metabolism and Ferment Industry

第2页：An Overview metabolismmetabolism：the

An Overview metabolismmetabolism：the sum total of all chemical reactions occurring in the cell metabolismcatabolismanabolismComplex moleculescatabolismanabolismSimple moleculesATP[H]

第3页：Section 1 Energy Metabolism

Section 1 Energy Metabolism in MicrobesPrimary EnergyOrganic CompoundsSunlightInorganic Compoundsin Reduced State ATPATPChemoheterotrophPhotoautotrophPhotoheterotrophChemoautotrophsummarize

第4页：The breakdown of glucose

The breakdown of glucose to pyruvate fermentationrespiration（aerobic or anaerobic respiration）Chemoheterotrophbiological oxidationand energy ReleaseProcess——Dehydrogenation, Giving Hydrogen and Accepting Hydrogen (Electron)Function——Releasing Energy (ATP), Engendering Reducing Power [H] and Producing Intermediate Metabolitesbiological oxidation

第5页：

第6页：Glocose——representativesubstrateofbiologicaloxidationEmbden-Meyerhof-ParnasPathw

Glocose——representativesubstrateofbiologicaloxidationEmbden-Meyerhof-ParnasPathway(Glycolysis)HexoseMonophosphatePathwayEntner-DoudoroffPathway(KDPGPathway)PK(phosphoketolase)pathway1 The breakdown of glucose to pyruvate

第7页：1）Embden-Meyerhof-Parnas

• 1）Embden-Meyerhof-Parnas Pathway(EMP)(Glycolysis, Hexose Diphosphate Pathway)glucosepyruvatewith O2：connecte EMP pathway with TCA pathway；without O2：reduce somemetabolismproduct, onlyenergy-yielding process.generates ATPbysubstrate-level phosphorylation：（1）glyceraldehyde 1,3-phosphate
• 3-

第8页：Uses pentoses and

Uses pentoses and NADPHOperates with glycolysis2)Hexose Monophosphate Pathway (HMP)(PentosePhosphatePathway,PhosphogluconatePathway,Warburg-DickensPathway)

第9页：fructose 6-phosphates：be

fructose 6-phosphates：be converted toglucose 6-phosphates，be returned toPentose Phosphate Pathwayglyceraldehyde 3-phosphate：a.throughEMP pthway，be converted to pyruvate，intoTCApthwayb.converted toHexose Phosphate,be returned to Pentose Phosphate PathwayThe overallreaction：6glucose 6-

第10页：3) Entner-Doudoroff

3) Entner-Doudoroff Pathway (KDPG Pathway)1952,Entner-Doudoroff ：Pseudomonas saccharophilaprocess：（4 septs）1 Glucoseglucose 6-phosphates 6-phosphogluconateKDPG6-phosphogluconate dehydrataseglyceraldehyde 3-phosphate+ pyruvate2-oxo-3-deoxy-6-phosphogluconatealdolaseProduces NADPH and 1 ATPDoes not involve glycolysisPseudomonas, Rhizobium, Agrobacterium

第11页：4) phosphoketolase

• 4) phosphoketolase pathway (PK)a.Pentose phosphoketolas PathwayGxylulose 5-phosphateacetyl phosphate +glyceraldehyde3-phosphatephosphoketolaseethanolpyruvateLactic acid1 G
• Lactic acid+ ethanol+ 1 ATP+ NADPH + H+

第12页：Gfructose 6-phosphatesb.Hexose

• Gfructose 6-phosphatesb.Hexose phosphoketolas Pathway (HK)（Bifidobacterium bifidum）Erythrose-4-P+ acetyl-phosphatesphosphoketolaseglyceraldehyde 3-phosphate+ acetyl-phosphatesxylulose-5-Pribulose-5-PAcetic acidphosphoketolasefructose 6-phosphatesLactic acidAcetic acid1 G
• Lactic acid+ 1.5 Acetic acid+ 2.5ATPacetokinase

第13页：1.definitionsbroader

1.definitionsbroader：usemicroorganism to produceusefulmetabolic productnarrower：under anaerobic conditions,be defined as an energy-yielding processusing itselfmetabolic intermediates asthe final hydrogen

第14页：2. fermentationsorts

• 2. fermentationsorts1）alcoholfermentationa. yeasts1 G 2 pyruvate
• 2 aldehyde+ CO2
• 2 ethanol+2 ATPcondiction：pH 3.5~4.5 , without O2Strain：Saccharomyces cerevisiae, few bacteria(Erwinia amylovora, Sarcine vintriculi)
• I. Add NaHSO4NaHSO4 + aldehyde
• sulfonic hydroxy aldehydeii.weak basic（pH
• 7.5）2 aldehyde
• 1 acetate + 1 ethanolglycerolfermentation: dihydroxyacetone as hydrogenaccepter, hydrolyzed to glycerol（EMP）

第15页：b.bacteria(Zymomonasmobili

• b.bacteria(Zymomonasmobili, Pseudomonas saccharophila)homoalcoholfermentation1 G 2 pyruvate（ED）ethanol+1ATPheteroalcoholfermentation(Thermoanaerobacter ethanolicu)1 G 2 pyruvate（Pyruvate formate lyase）aldehyde
• ethanolformic acids+ acetyl-CoAWithout PyruvatedecarboxylateWith aldehyde dehydrogenase

第16页：2）Lactic acid fermentationHomolactatefermentationFor

• 2）Lactic acid fermentationHomolactatefermentationFor example, Lactobacillus delbruckii, Streptococcus faecalis——EMP pathway（pyruvate lactate）Heterolactatefermentation（PKpathway）Leuconostoc mesenteroides（PK）generates energy：1ATPBifidobacterium bifidum（PK、HK）generates energy：2G
• 5 ATP, 1G
• 2.5ATP

第17页：3) mixed acid, butanediol

3) mixed acid, butanediol fermentationa.mixed acid fermentation：——E.coli, Salmonella, Shiella1 Gpyruvatelactatelactatedehydrogenaseacetyl-CoA+formylPyruvate formate lyaseoxaloacetatePropionicacidMethylmalonyl CoAcarboxyltransferasephosphotransacetylasealdehydedehydrogenaseacetokinaseAlcohol dehydrogenaseacetateethanolCO2+ H2

第18页：b.butanediol fermentation——Enterobacter

• b.butanediol fermentation——Enterobacter, Serratiapyruvateacetolactate3-hydroxy butanonediacetylRed substance(acetolactatedehydrogenase)（OH-、O2）neutralbutanediolTwo important reaction:1.
• V.
• P. test
• 2. methylene red (M.R) testEnterobacter aerogenes: methylene red （-）E.coli: V.P. （-）, methylene red （+）V.P. test:

第19页：4)acetone-butanol

4)acetone-butanol fermentation（mixed, acetone:butanol: ethanol = 3：6：1）——Clostridium acetobutyricum2 pyruvate2 acetyl-CoAacetoacetyl-CoAacetone+CO2（acetate CoA transferase）butanolacetyl-CoA acetyltransferase（acetoacetate decarboxylase）

第20页：5）stickland reactionMain

5）stickland reactionMain point：amino acid oxidationcouples with other amino acids reduction, generates 1ATPhydrogendonors(oxidation) amino acid:Ala, Leu, Ile, Val, His, Ser, Phe, Tyr, Tryhydrogenacceptors (reduction) amino acid:Gly, Pro, Arg, Met, Leo, and so on.

第21页：The Stickland reactionis

The Stickland reactionis used to oxidizeseveral amino acids: alanine, leucine,isoleucine, valine, phenylalanine,tryptophan, and histidine. Bacteria alsoferment amino acids (e.g., alanine, glycine,glutamate, threonine, and arginine) byother mechanisms.

第22页：Oxidized glycinepyruvate-NH3NAD+NADHacetyl-CoANAD+NADHacetate+

Oxidized glycinepyruvate-NH3NAD+NADHacetyl-CoANAD+NADHacetate+ ATPalanineacetatealanine-NH3Reducedone amino acid is oxidized and a second amino acid acts as the electron acceptor.

第23页：3 Respirationaerobic

3 Respirationaerobic respirationanaerobic respiration1. Aerobic Respiration:The final electron acceptor in the electron transport chain is molecular oxygen (O2).Respiration

第24页：Give the substrate

Give the substrate and products of the tricarboxylic acid cycle.To provide carbon skeletons for use in biosynthesisWhat chemical intermediate links glycolysis to the TCA cycle?The complete cycle appears to be functional in many aerobic bacteria, free-living protozoa, and most algae and fungi. （1）Tricarboxylic Acid Cycle (Krebs Cycle)

第25页：（2）The Electron Transport

（2）The Electron Transport ChainSome important electron transport chain carriers of the respiration chain in microbesNicotianamideadeninedinucleotide(NAD)andnicotianamideadeninedinucleotidephosophate(NADP)Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN)Iron-sulphur proteinUbiquinone (Coenzyme Q) Cytochrome system

第26页：The Mitochondrial

The Mitochondrial Electron Transport Chain. Many of the more important carriers are arranged at approximately the correct reduction potential and sequence. In the eucaryotic mitochondrial are organized into four complexes that are linked by coenzyme Q (I and cytochrome c (Cyt c). Electrons flow from NADH and succinl down the reduction potential gradient to oxygen.

第27页：The electron transport

• The electron transport chain inProkaryoteMain outline:electron accepter multiplicity：O2, NO3-, NO2-, NO-, SO42-, S2-, CO32-et al；Electron donors：H2, S, Fe2+, NH4+, NO2-, G, other orgnisim et al；variouscytochrome：a, a1, a2, a4, b, b1, c, c1, c4, c5, d, o；Terminal oxidase：cyt a1, a2, a3, d, o，catalase, peroxid enzyme；Respiration Chaincomponent variable, being branchedrespiration chain：Bacterial chains also may be shorter and have lower P／O ratios than mitochondrial transport chains，from the several position of electron transport chain into and off by Terminal oxidase in several position.E.coli （absent O2）CoQ
• cyt.b556
• cyt.o cyt.b558
• cyt.d The cytochromes0 branch has moderately high affinity for oxygen，is a proton pump，and operates at higher oxygen concentrations;The cytochromesd branch has very high affinity for oxygen and functions at low oxygen levels。electron transport multiplicity.

第28页：（3）Oxidative phosphorylqtionChemiosmotic

（3）Oxidative phosphorylqtionChemiosmotic hypothesisChemiosmotic hypothesis-first formulated in 1961 by the British biochemist Peter．Mitchell.According to the Chemiosmotic hypothesis,the electron transport chain is organized so that protons move outward from the mitochondrial matrix and electrons are transported inward. Protons movement may result either from carrier loops,as shown in figure 9.14,or from the action of special proton pumps that derive their energy from electron transport.The result is proton motive force(PMF), composed of a gradient of protons and a membrane porential due to the unequal distribution of charges.When protons return to the mitochondrial matrix driven by the proton motive force,ATP is synthesized in a reversal of the ATP hydrolysis reaction.

第29页：The final electron

• The final electron acceptor in theelectron transport chain is not O2. Yields less energy thanaerobic respiration because only part of the Krebs cyclesoperations under anaerobic conditions.Nitrate Respiration（Denitrification）Nitratereductionoutline：
• a. have completely Respiration system；
• b. in the absence of O2 only，nitratereductase A and nitrous acidreductase needing for Denitrification are induced.c. facultativeanaerobicbacteria: Bacillus licheniformis, Paracoccus denitrificans, Pseudomonas aeruginosaand so on.2. Anaerobic Respiration

第30页：Nitrate RespirationHomotype：NO3-NH3-NR-NH2Hetertype：in

Nitrate RespirationHomotype：NO3-

• NH3-N
• R-NH2Hetertype：in the absence of O2，use NO3-as the final hydrongen accepterNO3-
• NO2
• NO
• N2O
• N2denitrification：1)make N（NO3-）in soil reduced intoN2，and disappear,reduce edaphic fertility；2) Denitrification has the importance action in nitrogen cycle.
• NiRN2ORNORNaR
• Facultative anaerobe (viz denitrify bacteriua)

第31页：Sulfate Respiration(sulfate

• Sulfate Respiration(sulfate reduction）——in the absent of O2,SO42-, SO32-, S2O32-as the finalelectron accepteroutline:a. obligate anaerobic bacteria；
• b. mostly ancient bacteriac. mostil obligate chemoheterotroph，few mixed；
• d. end product: H2S；SO42-
• SO32-
• SO2
• S
• H2S
• e. use organic nutrients（organic acid, fatty acid, 醇类）as hydrogendonorsor electrondonors；
• f. environment：contain SO42-,anaerobicenvironment（soil, seawater）Forexample,Desulfovibriodesulfuricans,D．Gigas,Desulfotomaculumnigrificansandsoon.

第32页：Sulfur Respiration（Sulfur

Sulfur Respiration（Sulfur reduction）——useelementSulfurasthe finalelectron accepteronly.electrondonors：aceticm acid, small peptide,glucose,carbohydrate polymers;For example, Desulfuromonas acetoxidansCarbonate Respiration（Carbonate reduction）——use CO2、HCO3-

第33页：other anaerobic respiration——useFe3+,Mn2+

• other anaerobic respiration——useFe3+,Mn2+, many organic oxide asthe finalelectron accepterfumaric acid
• succinate+ 1 ATPFor example, Escherichia, Proteus, Salmonella, Klebsiellain some facultative anaerobic bacteria, Bacteroides, Propionibacterium, Vibrio succinogenesin some anaerobic bacteria.Use Desulfotomaculum auripigmentum reduces AsO43-into As2S3

第34页：Section2specialmetabolisminmicrobes1

Section2specialmetabolisminmicrobes1 Bacterial Photosynthesis1. Cyclic photophosphorylation2. Noncyclic photophosphorylation3. Photosynthesis of purple membrane in halophilic bacteria

第35页：purple sulfur bacteria:Chromatiumpurplenonsulfur

purple sulfur bacteria:Chromatiumpurplenonsulfur bacteria:Rhodospirillum, Rhodopseudomonasgreen sulfur bacteria:Chlorobiumgreen nonsulfur bacteria :Chloroflexus

第36页：Thephotosyntheticelectrontransportsysteminthepurplenonsulfurbacterium,Rhodobacte

Thephotosyntheticelectrontransportsysteminthepurplenonsulfurbacterium,Rhodobactersphaeroides.Thisschemeisincompleteandtentative.Ubiquinone(Q)isverysimilartocoenzymeQ.BPhstandsbacteriopheophytin.NAD+andtheelectronsourcesuccinateareincolor.Purple NonsulfurBacterial Photosynthesis. Cyclic photophosphorylation

第37页：LightenergyisusedtomakeATPbycyclicphotophosphorylationmoveelectronsfromsulfurdon

LightenergyisusedtomakeATPbycyclicphotophosphorylationmoveelectronsfromsulfurdonors(greenandblue)toNAD+(red).Theelectrontransportchainhasaquinonecalledmenaquinone(MK).Green SulfurBacterial Photosynthesis.The photosynthetic electron transport system in the green sulfur bacterium, Chlorobium limicola.

第38页：2）noncyelic photophosphorylationElectrons

2）noncyelic photophosphorylationElectrons also can travel in a noncyclic pathway involving bothphotosystems. P700 is excited and donates electrons to ferredoxin asbefore. In the noncyclic route, however, reduced ferredoxin reducesNADP+ to NADPH .

第39页：noncyelic photophosphorylation

noncyelic photophosphorylation

第40页：electronsflowfromwaterallthewaytoNADPwiththeaidofenergyfromtwophotosystems,ATPis

electronsflowfromwaterallthewaytoNADPwiththeaidofenergyfromtwophotosystems,ATPissynthesizedbynoncyelicphotophosphorylation.oneATPandoneNADPHareformedwhentwoelectronstravelthrough

第41页：

第42页：3) Photosynthesis of

3) Photosynthesis of purple membrane in halophilic bacteriaHalobacteriumuses bacteriorhodopsin, not chlorophyll, to generate electrons for a chemiosmotic proton pump.

第43页：

第44页：2 ChemolithotrophBiological

2 ChemolithotrophBiological Oxidation, Energy Release and CO2Fixation in ChemoautotrophaerobicOxidationof inorganicelectron donorsgenerates ATPby Oxidative Phosphorylationelectron donors: H, reducing nitride, reducing sulphide and Fe2＋. Use CO2Fixation of Calvin cycle as carbon resourcesCO2 reduced to [CH2O]——consume much energy and reducing power

第45页：1.EnergymetabolismofnitribacteriaOxidationNitrobacter

1.EnergymetabolismofnitribacteriaOxidationNitrobacter: NH3 NO2-OxidationNitrosomonas:NO2-NO3-When two genera such Nitrobacterand Nitrosomonastogether in a niche, ammonia is grow converted to nitrate, a process called nitrification

第46页：2. Hydrogen oxidizing

• 2. Hydrogen oxidizing bacteriaMain strains:Alcaligenes, Flavobacterium AquaspirillumMycobacterium Nocardia and so on.generates energy：2H2+ O2—
• 2 H2Osynthesize reaction：2H2+ CO2—
• [ CH2O ] + H2O。

第47页：

第48页：3.Sulfur BacteriaEnergy

3.Sulfur BacteriaEnergy Metabolism of Sulfur Bacteria ThiobacillusEnergysource:Thiosulfatefreelysolubleinwaterandintheneutralcondition.The respiratory chain of Thiobacilli: NADH2 dehydrogenase, Fumaric reductase, flacoprotein（FP）, ubliquinone（CoQ）, cyt b, Cytochrome oxidase aa3

第49页：energy-yielding process

energy-yielding process :First sept: H2S, S0, S2O32－, oxidatived to SO32－Second sept: SO32－oxidatived to SO42－and generates energy

第50页：(1) iron bacteria(iron

(1) iron bacteria(iron oxidizing bacteria)oxidativeFe2＋into Fe3＋and generatesenergy.For example,Ferrobacillus,Gallionella,Leptothrix,Crenothrix andSphaerotilus;

第51页：Ironoxidizingbacteria:energy-yielding

Ironoxidizingbacteria:energy-yielding process by Oxidative Phosphorylation

第52页：(2)bacterial leachingPrinciple:a.2S

• (2)bacterial leachingPrinciple:a.2S + 3O2 + 2H2O —
• 2H2SO44FeSO4+ 2H2SO4+ O2 —
• 2Fe2（SO4）3+ 2 H2Ob.CuS + 2 Fe2（SO4）3+ 2H2O + O2—
• CuSO4+ 4FeSO4+2H2SO4c.CuSO4+ Fe —
• FeSO4+ Cu

第53页：3 Biologic Fixation

3 Biologic Fixation of Nitrogen1. Kinds of nitrogen fixing microorganismFree-living nitrogen fixing bacteria Symbiosis nitrogen fixing bacteria Association nitrogen fixing bacteria

第54页：SupplyingATPReducingForce[H]anditsCarrierNitrogenase

SupplyingATPReducingForce[H]anditsCarrierNitrogenase (molebdoferredoxin, azoferredoxin)N2Mg2+Strict Anoxy microenvironment2. The necessary condition of Nitrogen fixation

第55页：1966，M．J．DilworthandR．ScholhornNitrogenase:N2NH3①N2ON2+H2O②N3-N2+NH3③C2H2C2H4④HC

1966，M．J．DilworthandR．ScholhornNitrogenase:N2NH3①N2ON2+H2O②N3-N2+NH3③C2H2C2H4④HCNCH4+NH3+[CH3NH2]⑤CH3NCCH4+CH3NH2+[C2H4,C2H6]3.Determination of Nitrogenase Activity

第56页：4.The Biochemistry

4.The Biochemistry Pathway of Nitrogen FixationN2+6e+6H++12ATP2NH3+12ADP+12Pi5.Hydrogen Reaction of NitrogenaseN2NH3, 2H+H2N2+8H++8e+16Mg-ATP2NH3+H2+16Mg-ADP+16Pi

第57页：A. The Protection

A. The Protection Mechanism in Aerobic Free-living Nitrogen Fixting Bacteriaa. Breathing Protectionb. Conformation ProtectionB. The Protection Mechanism in Cyanobacteriaa. Special Reducing Heterocysts Differentiatedb. The Protection of Nitrogenase in Cyanobacteriathat don’t form heterocystsC. The Antioxygen Protection of Nitrogenase in Root Nodule Bacteriaa. Symbiosis Rhizobia in Leguminous Plantb. Symbiosis Rhizobia in nonleguminous Plant6. The antioxygen mechamism of Nitrogenase in Aerobic Nitrogen Fixing Bacteria

第58页：4 The Synthesis of

• 4 The Synthesis of PeptidoglycanA The Synthesis in Bacterial Cytoplasma G—
• G-UDP，M--UDPG—
• —
• 6-P-fructose—
• 6-P-glucosamine—
• —
• N-acetoglucosamine-1-P—
• N-acetylglucosamine-UDP—
• N-acetylmuramic acid-UDPbM—
• “Park” nucleotide（UDP-M-pentapeptide）UDP as carrier sugarD-Val-D-Val are repressed by cycloserine；

第59页：N-acetylmuramic acid

N-acetylmuramic acid“Park”nucleotide“Park” nucleotidehydrophilicity—

第60页：peptidoglycan unit

• peptidoglycan unit synthesisCarrier：bactoprenol（carrier lipoid）——C55-isoprenol（contain 11isoprenoid units）combinate to Gduringtransmembrane ，link into interpeptide bridge;carrier lipoid: concerned with the synthesize of polysaccharide and lipoidglycan in outer cell ( cellulose,polymannan, and so on）vancomycin，bacitracin inhibite some reactins
• B. The Synthesis in Bacterial Cytomembrane

第61页：“Park”nucleotide peptidoglycan

“Park”nucleotide peptidoglycan unitin Bacterial Cytoplasmin Bacterial Cytomembranein outside of Bacterial Cytomembrane

第62页：C.The Synthesis in

• C.The Synthesis in outside of Bacterial Cytomembranea.glycan chain extension（transverse link）:peptidoglycanmonomer+primer—
• glycan chain transverseextense one disaccharide unitb. Adjacent glycan chain connect（vertical link）:2D-Val—
• M-tetrapeptide+ D-Val—
• cross-

第63页：Transglycosylation

Transglycosylation and Transpeptidation

第64页：Section 3 microbial

Section 3 microbial secondary metabolismand its productThere are many kinds ofsecondary metabolitewhich primary metabolic products serve assubstrate, some of these products have a

第65页：Microbial secondary

Microbial secondary metabolism and its productRegulation of secondary metabolism1primarymetabolism2nitriccompound3inductionandfeedbackinhibition

第66页：Section 4 Regulation

Section 4 Regulation of metabolism andferment product practise.Metabolic regulation kinds are various,microorganism produce metabolic product tooffer service for fermentation industry and tobenefit for mankind with their relevant

第67页：Using microbial metabolic

Using microbial metabolic productMetabolic producttype：1 primary metabolic products:amino acid, enzyme or coenzyme；2 submetabolicproducts:antibiotic, hormone, alkaloid, toxin, vitamin, and so on.Fermentation type：1 Naturalfermentation: ethanol, lacate and so on，2 Metabolic controlfermentation: terminal products: lysine, guanylic acid, adenylic acid and so on ；metabolic intermediates: citrate,α-ketoglutaric acid, succinate,inosinic acid,xanthine nucleotide and so on；

第68页：Controloffermentcondiction1）cultrue

Controloffermentcondiction1）cultrue condition：temperature, pH and so on;2）nutrition component：glucose concentration, C/N, growth factor, and so on;3）dissolved oxygen: aeration numbr, agitation and so on.。

第69页：Control of Metabolic

Control of Metabolic regulation（1）auxotrophic regulatory mutantLysinefermentation——(homoserine auxotrophic mutant)

第70页：Microbial metabolism

Microbial metabolism and Metabolic engneeringMetabolic Engineering introduce xylose Metabolic pathwayXylose xylitolXyluloseXlulokinaseXylulose-5-PGlucosePyruvateEthanolXylose isomeraseXylose reductasexylitol dehydrogenasePentose phosphoketolasPathwayPichia stipitisbacteriaGlycolysisEntner-DoudoroffPathway

第71页：Using active metabolism

Using active metabolism in microbes1biotransformation,2microbialstrawxylan-degrading,3microbiohydrometallurgyandoilextraction,4biodegradation

第72页：References:PrescottLM,HarleyJP,andKleinDA.Microbiology(5thed.),Highereducationpr

References:PrescottLM,HarleyJP,andKleinDA.Microbiology(5thed.),HighereducationpressandMcGraw-HillCompanies,Inc.2002MichaelTM,JohnMM,JackP.Brockbiologyofmicoorganisms，Internationaledition,PearsonEducation,Inc.2003TalaroK.P.Foundationsinmicrobiology(FifthEdition),HighereducationpressandMcGraw-HillCompanies,Inc.2005