产几丁质酶细菌的鉴定与产酶和酶学性质的.研究

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1、四川大学硕t论文studieswillberesearchedontheisolationandscreeningofunknownchitinaseformingstrains．Also，thechitinasefrommicrobesmustbepurified，itscharacteristics，thewayitworksandtheeffectiveitproducesarethehotspotswhichresearchedOilbiocontroltoday．Thesubjectinourexperimentisatypicalinsect(Bomb

2、yxmori)，whichdiednaturally．Outwardly，thedeadbodyhadabigbrightcoeruleusspotontheircephalothorax．Achitinaseproductivestrainwasisolatedfromthenaturallydeadbody’Speritrophicmembraneinmidgut．Themaincompositionofperitrophicmembraneischitins，itisthefirstbarrierandplaysanimportantroleinprotec

3、tingthegutepitheliumfrominfectionofpathogens．Ifthisplaceisdegradated．theremustbesomethingwhichcanhydrolyzechitins．That’Swhywechosethisplacetoisolatethechitinaseproductivemicrobes．Inordertoenrichthechitinaseproductivemicrobeswhenweculturethemixturesampleonthescreeningmediumflatplate，we

4、usedcolloidalchitinastheonlycarbonsource．Doingthis，mostmicrobeswhichcan’tusechitinasitscarbonsourceareknockedout，leftonlythemicrobeswhichcanusechitinasitscarbonsource．Duringthesemicrobes，mostcanproducechitinase．Underasepsiscondition，wetakethesamplefromthedeadbody’Speritrophicmembranei

5、nmidgut，thenseparatedtheminspacebydrawlinesonthechitinflatplate．Theplateswereincubatedat28。Cfor72h．Mostmicrobesontheplatehashydrolyticcircle，whichcausedbythechitindegradation．Takenotetotheratioofthediameterofthehydrolyticcircletothediameterofthecolony．Bycomparison，wechoseahighyielding

6、chitinase-productingstrain，namedzll-r．Thisstrainisincubatedunderthesameconditionforfivegeneration，andrecordtheratioofthediameterofthehydrolyticcircletothediameterofthecolony．Fromthisresult，wecandiscoverthatthestrainzll-rhaschitinase-productinggeneticstability．Themethodtoconservethestr

7、ainisglycerolquickfreezingmethodandpetrolineslanttubemethod．Inordertoconformthefunctionofthisstraininbiocontrol，wedeterminatedthetoxicityofthestrainzll·rtotheBombyxmori，grasshoppersandcabbagebutterflylarva．ApurestrainisseparatedfromtheLBculture．ThenweinoculatedthepureVl四川人学硕士论文strainI

8、ntoth