The correlation of cellular changes with succinic dehydrogenase and cytochrome oxidase activities in the development of the cellular slime molds☆

[摘要] 1.1.Theactivitiesofsuccinicdehydrogenaseandcytochromeoxidasewerestudiedindifferentdevelopmentalstagesoftheslimemold,D.mucoroides,inparticular,thetransitionfromtheactivefeedingtothemorphogeneticstages.Cytochromeoxidaseactivitydecreasedduringtheinterphasebetweenthevegetativeandtheaggregationstages,andremainedlowinthemigratingpseudoplasmodium.Bycontrast,succinicdehydrogenaseactivityremainedlowduringtheearlypartofthegrowthperiodbutincreasedinactivity4–5hoursbeforetheinitiationofaggregation.2.2.Thetimeofthissuddenincreasecorrespondedwiththetimeoftransitionfromthelogarithmictothestationaryphaseinthegrowthcurveoftheamebas,anditwasfurthershownthatthiswastheperiodofdepletionofbacterialfoodsupplyandthecessationoffeeding.3.3.Alsoatthistime,thesmalldotlikeformofthemitochondriaseenintheearlierfeedingstagesbecamesupersededbynewfilamentlikestructures,andtheamebasshowedmoreactivepseudopodformationandgreaterrateofmovement.4.4.HistochemicalstudiesweremadetoexaminethepossibilityofdifferentialdistributionoftheseenzymesinthemigratingpseudoplasmodiaofD.mucoroidesandD.discoideum.InthecaseofD.mucoroidestheposterior,presporeregionshowedhigherenzymeactivitiesthantheanterior,prestalkregion.ThemigratingpseudoplasmodiaofD.discoideumdidnotshowcleardifferentialstainingbetweenthetworegionsforeitherreaction,althoughexperimentswithphenylurethaneseemtoindicatethatinoldermigratingpseudoplasmodia,thereisasimilar,butlatent,differentialpatternofcytochromeoxidase.5.5.InadditiontworeactionsforperoxidaseweretriedonthemigratingpseudoplasmodiaofD.mucoroides,butbothfailedtoshowanypositiveresult.

[学科分类] 生物科学（综合）