参考成果课件-growth

Lecture5-1MicrobialGrowthCHAPTER5BROCKBIOLOGYOFZhao ,ChenSchoolofLifeScienceandBiotechnologyShanghaiJiaoTongUniversity BacterialCellCellGrowthandBinaryInmicrobiologygrowth生长isdefinedasanincreaseinthenumberofcells.Bydefinitionwhenonecelldividestoformtwo,onegeneration世代hasoccurred.ShanghaiJiaoTongBinaryfissionBacterialInmostprokaryotes,growthofanindividualcellcontinuesuntilthecelldividesintotwonewcells,aprocesscalledbinaryfission.FtsproteinsandthecelldivisionFtsproteins(“filamentoustemperaturesensitive”)areimportantinthecelldivisionprocessofFtsproteinsareuniversallydistributedamongprokaryotes,includingtheArchaea,andFtsZproteinshavebeenfoundinmitochondria线粒体andchloroplasts叶绿体Fts蛋白广泛存在于原核生物FtsZshowsstructuralsimilaritiestotubulin微管蛋白theimportantcelldivisionproteinineukaryotes.ShanghaiJiaoTongInrod-shapedcells,formationofthedivisomebeginswith entofmoleculesofFtsZinaringaroundthecellintheprecisecenterofthecell.细胞的 (divisome),杆菌的 ThearrangementThearrangementindividualdivisomeZipAisanFtsZFtsIisapeptidoglycanbiosynthesisprotein;chromosomeFtsAisanCellsstainedwithaspecificreagentagainstFtsZBinaryDNAreplication,MinProteins,andCellDivisionLocationoftheactualcellmidpointbyFtsZisfacilitatedbyMinproteins,especiallyMinC,MinD,andMinE.Figure

CellSitesofcellwallsynthesis

MreBandDeterminantsofCellOtherkindsof2000chemicalreactionsinthecellEnergyBiosynthesisofmonomers,coenzymes,cofactorsPolymerizationreactions-synthesisofpolymersfromShanghaiJiaoTong LocalizationofnewcellwallsynthesisduringcelldivisionIncocci,newcellwallsynthesis(showningreen)islocalizedatonlyone.hanghaiShanghaiShanghaiJiaoTongReviewReview:thepeptidoglycanReview:Overallstructureofpeptidoglycanillustratingtherepeatingsugarsandcrossbridges.Bactoprenol细菌萜醇isaveryhydrophobicC55alcohol.BactoprenolBactoprenol细菌萜醇isaveryhydrophobicC55alcohol.Bactoprenoltransportspeptidoglycanbuildingblocksacrossthemembranebyrenderingtheprecursorssufficientlyhydrophobictopassthroughtheinteriorofthecytoplasmicmembrane.5.3.1Biosynthesisof5.3.2TranspeptidationthepenicillintargetTheThetranspeptidationreactionleadstothefinalcross-linkingoftwopeptidoglycanchains.Penicillininhibitsthisreaction.ShanghaiJiaoTongGrowthofBacterial细菌群体生What’sthedifferencebetweengrowthofmacroorganismsandmicroorganisms?Growthandreproductioncanbedistinctfor GrowthisincreaseinsizeandreproductionisincreaseinnumberGrowthandreproductionisthesameGrowthisanincreaseinthenumberofcells生ShanghaiJiaoTongBacteriaexistasIndividualcellshaveashortlifespan,Populationsarethewaybacteriaexistas Inmicrobiology,growth/reproductionisanincreaseinthenumber(ormass)ofcellsShanghaiJiaoTongGrowthterminologyandtheconceptofexponentialgrowthGrowth-anincreaseinthenumber(mass)ofmicrobialcellsinapopulationGrowthrate-thechangeincellnumberorcellmassperunittime生长率:单位时间细胞数量的变Generation-theintervalfortheformationoftwocellsfromone世代:一个细胞生成两个细胞的ShanghaiJiaoTongExponentialgrowthGrowthofamicroorganismwherethenumberofcellsdoublesduringeachunittimeperiodiscalledexponentialgrowth.对ShanghaiJiaoTongFigureGrowthrateiseverincreasinginexponentialgrowth对ThemathematicsofexponentialGenerationtimethetimerequiredforonegenerationtooccurforthecelltodoubleinapopulation一个世代产生所需的时间Inatimeoft,apopulationgrowngenerationstoincreaseitscellnumberfromN0toNN=N0Thegenerationtimeg=t/n=t/3.3(logN-Ifyoucanmeasurethegrowthtime,initialcellnumber,endcellnumber,generationtimecanthenbe

ShanghaiJiaoTongFigure

MethodofestimatingtheMethodofestimatingthegenerationtimes(g)ofexponentiallygrowingpopulationswithgenerationtimesof(a)6hand(b)2hfromdataplottedonsemilogarithmicgraphs.Theslopeofeachlineisequalto0.301/gandnequalsthenumberofgenerationsthathaveoccurredinthetime,t.Growthrateconstant生长速率常数(specificgrowthThenumberofgenerationsthatoccurperunittimeinanWhatwouldhappenifacellgrowexponentiallyforalongtime?StartfromasinglecellGenerationtime20minGrowexponentiallyfor48hrHowmanycellscanwegetintheend? = XHowmuchdotheyweight?•X1043cellsX10-12gram/cell=X1031X1025That’s4000timestheweightoftheShanghaiJiaoTongTheGrowthCycleInanenclosedvessel,referredtoasabatchculture,typicalgrowthcurveforapopulationofcellscanbeStationaryphase稳定期Deathphase衰亡期ShanghaiJiaoTongTypicalgrowthcurveofbacterialpopulationsinbatchculture批LagPhase迟滞生长timerequiredforexponentialgrowthtodependingonthehistoryofinoculumandgrowthThewaytoshortenlagIftheinoculumisinexponentialgrowthphase,growthconditionsarethesame,lagperiodisIftheinoculumhasbeenstoredinfridge,warmittogrowthtemperaturecanshortenthelagphase.periodthatthenumberofcellsdoublesduringeachunittimeCellsinmid-exponentialphaseareThincellusedforenzymeresearch,forgenetictransformationandforpurificationofcellcomponentsPeriodthatexponentialgrowthstopsandcellnumberremainconstantWhatstopsexponentialEssentialnutrientsdepletion(anessentialnutrientisusedup)必需营养成份的消耗WastesaccumulationCrypticgrowth-deathrateandgrowthrate DeathPhase衰亡PeriodofCelldeathandDeathphaseis