第六章胚胎在体外的维持VIP免费

动物繁殖学双语教学English-ChinishofReproductionginFarmAnimalTrainingmanuaiforembryotransferincattle第六章胚胎在体外的维持动物繁殖学双语教学Maintaining维持embryosinvitroChapter6Embryosderive得自nutrientsfromthefluidinwhichtheyarebathed;moreover,ofperhapsmoreimportance,embryosdependontheambient周围环境fluidtomaintaintheirphysiologicalintegrity完整性.动物繁殖学双语教学Todate,nochemicallydefinedmediumhasbeenformulated阐明tosupportnormaldevelopmentofbovineembryossatisfactorilyforlongerthanabout24hours.动物繁殖学双语教学However,severalmediaarecommerciallyavailable(orcanbepreparedeasily)thatadequatelymaintainembryosfortheusualintervalbetweencollectionandtransfer.Forlongerperiods,cryopreservation低温贮藏isrecommended.动物繁殖学双语教学STORAGECONDITIONSForshortperiodsofculture,thenutrientpropertiesofthemediumarefarlesscriticalthanpH,osmolality,temperature,sterility,andlackoftoxicity.动物繁殖学双语教学Anembryo'srangeoftoleranceforthesepropertiesisnarrow.Inadequate不充分的controloftheseaspectsofcultureaccountsformanyfailedtransfers.Inaddition:embryosaredamagedifexposedtoexcesslight(e.g.microscopelights)forprolongedperiods,butnormallightingordaylightintheworkareaisnotharmfulifembryosarenotexposedformorethanhalfanhour.动物繁殖学双语教学Bodytemperatureofcattleis39℃,andforcertainpurposesthistemperalureisappropriate.However,forroutine程序commercialembryotransferwedonotrecommendstorageabove37℃becausethermometers温度计,eventhoseonincubators孵卵器,arefrequentlyincorrectby1℃or2℃.Culturingembryosat41℃isextremelydamaging,whereasstoringthemforupto12hoursbetween18℃and37℃isnot.动物繁殖学双语教学MEDIAThesimplestmediumissterilesaline(9gmNaCl/litreofsterilized,deionized脱离子ordistilledwater).动物繁殖学双语教学Salinewillnotsupportembryonicdevelopment,butwillkeepembryosforafewhours;itisbettertousesalineandtransferembryosquicklythantouseamorecomplexmediumwithoutaproperbuffering缓冲(作用)system.动物繁殖学双语教学Moreover,salinecanbesteam-sterilized(atleast30minutesat121℃underapressureof104kilopascals千克力,)ifa0.22-gmbiologicalfiltrationsystemisnotavailable.Aseriousproblemwithsaline,however,isthatembryoswillfloat漂浮orsticktoplasticorglassunlessamacromolecule高分子suchasbovineserumalbumin(BSA)orserumisadded,bothofwhichrequiremembranefiltrationforsterilization.BSAandserumaresterilewhenpurchased.TABLE3Recommendedcultureconditiongs动物繁殖学双语教学Formostapplications,werecommendamodifiedDulbecco'sphosphatebufferedsaline(PBS).Itiseasytousebecauseitdoesnothavetobeequilibratedandmaintainedinanatmosphereof5percentCO2inair.动物繁殖学双语教学Itcanbepreparedfromstockreagents(Table4)orpurchasedineitherready-to-useorconcentratedform,whichmustbedilutedwithsterile,deionized脱离子剂ordistilledwater.动物繁殖学双语教学Afrequenterrorisfailuretodiluteconcentratedmedium;embryoscontractmarkedlywhenexposedtothehighosmolality同渗重摩.CommerciallyavailableDulbecco'sPBSdoesnotusuallycontainantibiotics,sodiumpyruvate丙酮酸盐(或酯),glucoseormacromolecules高分子.动物繁殖学双语教学Theleastimportantingredient因素istheNapyruvate丙酮酸钠;neitherNapyruvatenororganismsglucoseisneededformostapplications.TheCaC12andMgSO4canalsobeeliminated排除ifembryosaretobekeptinvitro在生物体外onlyashorttime.Iftheseareomitted漏检,osmolality同渗重摩shouldbeadjustedbyaddingextraNaC1.动物繁殖学双语教学Othermediausedtocultu...