1、Lecture5bMicrobialIV.EnvironmentalEffectsMicrobialLecture5bMicrobialIV.EnvironmentalEffectsMicrobialOsmolarity/WaterEnvironmentalfactorsaffecting bacterial growthOsmolarity/WaterEnvironmentalfactorsaffecting bacterial growth5.10Effect of Temperature 5.10.1CardinaltemperaturesMinimum temperaturetempe

2、rature below which growth no longer Optimum5.10Effect of Temperature 5.10.1CardinaltemperaturesMinimum temperaturetemperature below which growth no longer Optimum temperaturetemperature at which growth is most um temperature最高生長溫temperature above which growth is Cardinaltemperatures基本溫Cardinaltemper

3、aturesaregenerallycharacteristiceachtypeanismbutCardinaltemperatures基本溫Cardinaltemperaturesaregenerallycharacteristiceachtypeanismbutarenotyastheycanbemodifiedslightlybyotherfactorstheenvironment;inparticular,bythecom the growth medium.itionCardinaltemperaturesandCardinaltemperaturesandthemolecularc

4、onsequen the cell基本溫度與分子活性的關系FigTheoptimumtemperatureTheoptimumtemperatureisalwaysnearerntheFig5.10.2Temperatureclassesanisms Psychrophile嗜冷Psychrotrophs/冷菌/兼性嗜冷Mesophile嗜溫Thermophile嗜5.10.2Temperatureclassesanisms Psychrophile嗜冷Psychrotrophs/冷菌/兼性嗜冷Mesophile嗜溫Thermophile嗜熱ivepsychrophile嗜熱Psychroph

5、iles:growthwellat0Hyperthermophiles:havehavPsychThermopoptiman80Candof1Psychrophiles:growthwellat0Hyperthermophiles:havehavPsychThermopoptiman80Candof1psych growthoptima higher.The113C.Theyusuallydonotarothough haveatemperaroundbelow ubetn55andC,and Fig.6.17 5.12 Microbial growthigh 5.11Microbialgro

6、w t5.12 Microbial growthigh 5.11Microbialgrow tAsmallsuperheatedboilingspringAsmallsuperheatedboilingspringin YellowstoneNationalPark.spring have a temperature 12C above the boiling po . The mineral de itsconsistsmainlyofsilica andsulfur.Micro anisms tcan grow in it are hyperthermophiles.Thermophili

7、cprocaryotes en reported growing in Thermophilicprocaryotes en reported growing in Evidence has been presented reproduce at 113 C.t these microbes can grow vebe 5.12.1MolecularbasisgrowingatextremeMolecularadap ionsofenzymestoCold-active enzymes are more flexible due to higher portionofhelixandlessa

8、mountof-sheet耐冷的Heatresistantenzymes:moresaltbridgesand5.12.1MolecularbasisgrowingatextremeMolecularadap ionsofenzymestoCold-active enzymes are more flexible due to higher portionofhelixandlessamountof-sheet耐冷的Heatresistantenzymes:moresaltbridgesanddenselypackederior(comparedtheirmesophile區域-helixpr

9、ovides -helixprovides 多彈-sheet causes morerigidity帶來更多剛More-helixesMore-helixesorestructure,whichiscoldMoreMore-sheetsresultinamorerigid structure, which is less cold active2. MolecularionsofcellmembranesextremeCold-resistantcellshavemoreunsaturatedfatty2. MolecularionsofcellmembranesextremeCold-res

10、istantcellshavemoreunsaturatedfatty(morederlowtemperatures)thermophileshavesrichinsaturatedfatty(membranesremainstableandfunctionalatLifeplantoilcontainsmorefattyacids,thusremaininliquideesolidatthetemperatures,whileanimaltemperatures生活經驗:植物油因有3.Hyperthermophiles(Archaea)3.Hyperthermophiles(Archaea)

11、havemembraneasmonolayer,whichisresistanttopeelingIndustrialapplicationofIndustrialHigherLowerTaqDNApolymeraseandIndustrialapplicationofIndustrialHigherLowerTaqDNApolymeraseandRepetitivemeltingand95oC-52oC-SomeanismhasapHrangewithinwhichgrowthsibleandusuallyhasawell-definedpHoptimum.SomeanismhasapHra

12、ngewithinwhichgrowthsibleandusuallyhasawell-definedpHoptimum.anismsshowagrowthpHrangeof2-3.MostnaturalenvironmentshavepHvaluesnand9,anismswithhisrangemostcommon.自然界pH范圍一般是5-9適應這一5.13 Microbial GrowtLowand High pHExtreme alkaliphiles have growthoptimaatpH10orExtreme alkaliphiles have growthoptimaatpH

13、10orhigherAlkaliphiles prefer the growth optimumpHrangeof8.5to11.5Neutrophilesgrowthoptimum pH betn pH 5.5 and 8.0Acidophiles have their growth optimum betnpH0and5.5;Optimal growth pH represents the pH of the extracellularenvironmentonly最適生長pH指的racellularOptimal growth pH represents the pH of the ex

14、tracellularenvironmentonly最適生長pH指的racellularpHmustremainnearneutralityordertopreventdestructionofacid-oralkali-在中性附近he cell.細胞內pH值一般保Inextremeacidophilesorextremealkaliphiles,racellularpHmayvarybyseveralits嗜酸/堿菌的胞內pH可能偏中性幾ernalCellpH胞內pHWateractivity:aw,isaratioofthereoftheairWateractivity:aw,isarat

15、ioofthereoftheairinequilibriumsubstanceorsolutiontothevaporpre pure water. 水分活度reOsmosis: water diffuses from a region of high waterconcentration(lowsoluteconcentration)to a region of lower water concentration (highersolute滲透作hesof5.14OsmoticEffectsonGrowth 滲透壓影響 Halophiles: Etanisms: tolerateaw ofe

16、nvironmentgenerallyabsenceofaddedsoluteFigure6. of microEffectofsodiumionconcentrationongrowth Halophiles: Etanisms: tolerateaw ofenvironmentgenerallyabsenceofaddedsoluteFigure6. of microEffectofsodiumionconcentrationongrowth Osmophilesabletoliveinenvironmentshighin Osmophilesabletoliveinenvironment

17、shighin Xerophilesabletogrowinverydryenvironments (made dry by lack of water) 耐旱生物Aerobes好氧Strict Aerobes專性好氧Microaerophiles微好氧ive Aerobes好氧Strict Aerobes專性好氧Microaerophiles微好氧ive aerobes兼性厭氧Anaerobes厭氧Aerotolerant anaerobes耐氧的厭氧Obligate (strict) anaerobes專性厭氧5.15Oxygenandmicrobial(a)(b)(d(e)Aerotol

18、erantanaerobesthroughoutthetube.However,growthdisgroawnobetter(a)(b)(d(e)Aerotolerantanaerobesthroughoutthetube.However,growthdisgroawnobetternearthesurfacebecauseae theanismscanonlycanbacteria are InoculatedeachA small amount ofagarhasbeen added to keep the liquid fromis added as aredoxindicator: p

19、ink when oxidized and colorless when Q1:WhichQ1:Whichone(s)cangrow presence of oxygen?Q2:Q2:DotheyreallyuseoxygenQ3:WhichQ3:Whichone(s)canabsenceofTypeofWithoxygenWithout+-+ -+TypeofWithoxygenWithout+-+ -+ +Typesofbacteriainrelationto5.16ToxicformsofOxygeninitsnormalgroundeisreferredtoas5.16Toxicfor

20、msofOxygeninitsnormalgroundeisreferredtoasoxygen3O2).Onemajorformoftoxicoxygenissingletoxygen(1O2),higher energy form of oxygen. Carotenoids can convert singletoxygentonontoxicforms.單線態氧因有高能量而性Superoxideanion(O -),hydrogenperoxide(H O ),2hydroxylradical(OHareby-productsduringthereduction of O2 to H2

21、O in respiration.超氧陰離子,過氧化氫,羥基Toxicformsofoxygenproducedduringthe reduction of O2Toxicformsofoxygenproducedduringthe reduction of O2 to H2O in respiration.Figure:06-Figure:06-DetoxificationbyAerobesandiveaerobesgenerallycontainsuperoxide dismutase and catalase, although a few obligate aerobeslackcat

22、alase.TheabsenceofsuperoxideAerobesandiveaerobesgenerallycontainsuperoxide dismutase and catalase, although a few obligate aerobeslackcatalase.Theabsenceofsuperoxidedismutasein obligate anaerobes may be the reason why oxygen is toxic to酶Someaerotolerantchaslacticacidbacteria,superoxidedismutase,butt

23、heyuseprotein-freeMn2+tocarryouttheionofO - toH andO 2基InsomeArchaea,superoxidedismutaseisabsentbutaenzyme,superoxidee,ispresentandisresponsiblesuperoxideremoval.一些古生菌以過氧化物還原酶來替代AheavyloopfulAheavyloopfulofcellsfromanagarculturewasmixedonaslidedrop30%hydrogenperoxide.Theimmediateappearanceofbubblesisindicativeof the presence of catalase. The bubbles are O2 pr