華癸中生根瘤菌類菌體發(fā)育基因bacA的研究.pdf

1、華中農(nóng)業(yè)大學(xué)博士學(xué)位論文華癸中生根瘤菌類菌體發(fā)育基因bacA的研究姓名：譚雪娟申請學(xué)位級別：博士專業(yè)：微生物學(xué)指導(dǎo)教師：周俊初20090501華中農(nóng)業(yè)大學(xué)博士學(xué)位論文AbstractMesorhizobiumhuakuiiiscapableoffixingatmosphericnitrogeninsymbiosiswiththelegumeAstragalussinicus，whichisaneconomicallyimportantf

2、orageandgreenmanuregrowinginwinterthroughoutEasternAsiaSofar，littleisknownaboutthemolecularbasisofeventsafterthebacteriaarereleasedfrominfectionthreadsintothenodulecellsandbeforenitrogenfixationbeginsInthisstudy、abacAgen

3、ehomologueofSmelilotiwasisolatedfromMhuakuiiAlignmentofBacAaminoacidsequencesandtopologicalpredictionforcytoplasmicmembrane—spanningregionbothdemonstratedthattheBacAproteinofMhuakuiishowedhighhomologyto&melilotiFurthermo

4、rephylogeneticanalysisillustratedthatBacAofMhuakuiiwasmuchclosertoBacAofsmelilotiratherthanSbmAofEcoli、whichisfunctionallyinterchangeablewithBacAofSmelilotiInactivationofthebacAgeneabolishedtheabilityofMhuakuiitoestablis

5、hasuccessfulsymbiosiswithitshostComparedwithwildtypeMhuakuiithebacAmutantM1wasmoresensitivetocellenvelopedisruptingagents(acidpH，ethanol，SDS，andcrystalviolet)andshowedincreasedresistancetobleomycin，aglycolpeptideantibiot

6、icMassspectrometryanalysisrevealedthatBacAaffectedtheverylong—chainfattyacids(27OHC一28：0and29一OHC30：0)contentsoflipidAinMhuakuiiTheevidencesfromthisstudysuggestthatthecellenvelopewasalteredinthebacAmutantofMhuakuiiThisal

7、terationofcellenvelopemayalsofrustratebacterialattemptstosurvivetheenvironmentalchangencounteredwithinhostcells，whilethereisrioevidencewhetherthischangeofcellenvelopeisrelatedtotheunusuallipidAmodificationKeywords：Mesorh