Gastrular arrest and the control of autolytic activity in the egg of Rana pipiens: the comparative effects of oxygen, supramaximal temperature, and dinitrophenol☆

[摘要] 1.1.EggsofR.pipiensexposedto4–7atmospheres(abs.)ofpureoxygenforfrom12to24hourswhileinpregastrularstagesareunabletodevelopbeyondtheyolkplugstage.Eggsarrestedinthiswayundergonovisibleautolyticchangesbutremainintactforseveralweeksprovidedrelativelyasepticconditionsexist.Developingeggstreatedwithsulfhydrylcompoundssuchasreducedglutathione,BAL,andβ-mercaptoethylaminecauseseggsingastrulararrestrapidlytoundergoautolysis.2.2.Employingacasein-ureasubstrate,thecathepticactivityofeggsandembryosofR.pipienswasdeterminedatvariousstagesfromfourcellstotailbud.Themostsignificantincreaseinenzymeactivityoccurredimmediatelyfollowinggastrulationandcontinuingthroughthetailbudstagewhenintensiveyolkutilizationbytheembryoisbeginning.3.3.Thecathepticactivityofoxygen-arrestedgastrulaewasfoundtobeconstantandlowaslongas100hoursafterinitiationofthegastrularblock.Norecoveryofenzymeactivitycouldbedemonstrated,andtheseeggsshowednoautolyticchangesformanydaysaftertheirreturntonormalair.TheabilityofoxygentoinhibitautolysisappearstobeareflectionofthesulfhydryldependencyofthecathepsinsandissuggestiveofadirecteffectonendogenouscellularSHbymolecularoxygen.4.4.Eggsblockedatgastrulationbyexposuretosupramaximaltemperaturesortodinitrophenolunderwentrapidautolysisastheircathepticactivitymarkedlyincreased.5.5.Nodirectrelationshipbetweentheinhibitionofcathepsinbyoxygenandtheoxygen-inducedgastrulararrestcouldbedemonstrated.6.6.Theprobablerelationshipbetweenproteolyticactivityandoxidativemetabolismareconsideredinrelationtothecomparativeeffectsobtainedwithgastrulararrestsproducedbyexposuretooxygen,supramaximaltemperature,anddinitrophenol.Thepossibilityofoxygenactingonspecificsubcellularparticlesandtherebycontrollingautolysisispresented.

[学科分类] 生物科学（综合）