Lab2土壤细菌的分离与纯化

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1、实验二土壤细菌的分离与纯化一　教学要求通过从土壤中分离纯化细菌，初步掌握微生物的分离纯化方法和无菌操作技术。二　实验原理-常用的分离纯化方法microorganismsexistinnatureasmixedpopulations.However,tostudymicroorganismsinthelaboratorywemusthavethemintheformofapureculture,thatis,oneinwhichallorganismsaredescendantsofthesameorganism.单细胞挑取法简易单细胞挑取法micr

2、omanipulator平板分离法streakplatemethodThemostcommonwayofseparatingbacterialcellsontheagarsurfacetoobtainisolatedcoloniesisthestreakplatemethod.Itprovidesasimpleandrapidmethodofdilutingthesamplebymechanicalmeans.Astheloopisstreakedacrosstheagarsurface,moreandmorebacteriaarerubbedof

3、funtilindividualseparatedorganismsaredepositedontheagar.Afterincubation,theareaatthebeginningofthestreakpatternwillshowconfluentgrowth,whiletheareaneartheendofthepatternshouldshowdiscretecolonies.pourplatemethodAnothermethodofseparatingbacteriaisthepourplatemethod.Withthepourp

4、latemethod,thebacteriaaremixedwithmeltedagaruntilevenlydistributedandseparatedthroughouttheliquid.Themeltedagaristhenpouredintoanemptyplateandallowedtosolidify.Afterincubation,discretebacterialcoloniescanthenbefoundgrowingbothontheagarandintheagar.spreadplatemethodThespinplate

5、methodinvolvesdilutingthebacterialsampleintubesofsterilewater,saline,orbroth.Smallsamplesofthedilutedbacteriaarethenpipettedontothesurfaceofagarplates.Asterile,bent-glassrodisthenusedtospreadthebacteriaevenlyovertheentireagarsurface.三材料与器材金黄色葡萄球菌(Staphylococcus)和普通变形菌(Proteusv

6、ulgaris)斜面菌种。已灭菌的牛肉膏、高氏1号、土豆蔗糖培养各1瓶，49.5mL无菌水（带玻璃珠）1瓶、4.5mL无菌水6管、80%乙酸、10%酚酸、95%乙醇。无菌培养皿12套、1mL无菌移液管10支、土壤样品、天平等。四操作步骤制备土壤稀释液倾注平板培养接种和分离工具1．接种针2.接种环3.接种钩4.5.玻璃涂棒6.接种圈7.接种锄8.小解剖刀挑菌落isolationplate移接斜面常用的接种方法划线接种点接种穿刺接种涂布接种液体接种注射接种斜面接种时的无菌操作(1)接种灭菌(2)开启棉塞(3)管口灭菌(4)挑起菌苔(5)接种(6)塞好棉

7、塞纯化（平板划线法）倒平板——划线——培养——挑菌落——纯种（纯培养）平板划线分离的方法1.斜线法2.曲线法3.方格法4.放射法5.四格法五注意事项制备土壤稀释液时，要注意使土样均匀分散在稀释液中。注意无菌操作。六思考题试拟出从土壤中分离芽孢杆菌的主要实验步骤。如何检验平板上某个单菌落是不是纯培养？