英语翻译
InatypicalplasmidtransformationexperimenttherewillbeanextremelyheterogeneousmixtureofDNAmoleculeswithonlyasmallnumberconsistingofasinglevectormoleculelinkedtoasingleDNAfragment.WhenE.coliisusedfortransformationtheDNAmoleculesaremixedwiththebacterialcellsthathavebeenmadecompetentorpermeablebybeingexposedtoacoldsolutionofcalciumchloride(0.1M).Thecellsarethenwarmedto37℃for5minutestoallowtheDNAtobetakenup.ThecellsarethentransferredtobrothandafterashortincubationperiodareabletoexpressthefunctionsofthenewlyacquiredchimericDNA.Thebacteriacarryinghybridmoleculesareidentifiedbyaspecificscreeningprocedureandpurified:theirhybridplasmidsareisolatedandcharacterized,orthenewproductsareisolatedandstudied.Transformationefficienciesareabout10^6transformantsperμgcloningmixtureDNA.