Regulation and secretion of early developmentally controlled enzymes during axenic growth in Dictyostelium discoideum☆
[摘要] Thefourearliestdevelopmentallycontrolledenzymesinthecellularslimemold,Dictyosteliumdiscoideum,accumulateduringaxenicgrowthinrichmedia.WehaveshownthatatlowcelltitersthespecificactivitiesofN-acetylglucosaminidase,α-mannosidase,leucineaminopeptidase,andalaninetransaminaseareeachatveryloworvegetativelevelscomparabletoamoebaewhichhavebeengrownonbacteriaasthefoodsource.Duringtheexponentialphaseofgrowthallfourenzymesaccumulatedramaticallyreachingcellularspecificactivitiesatleastashighasduringdevelopment.Themagnitudeofthisaccumulationisinfluencedbyalterationsinthegrowthmedium.Wesuggestthattheseresults,combinedwiththoseofpriorinvestigations,indicatethatarestrictedsegmentofearlydevelopmentisinitiatedduringaxenicgrowth.Thismeansthatgrowthandearlydevelopmentarenotmutuallyexclusiveeventsinthisorganism.Thesecretionoflysosomalenzymesisalsoaffectedbythecompositionofthegrowthmedia.Inallmedia,includinggrowthinbacterialsuspensions,lysosomalenzymesaresecretedinsignificantquantities.Thereisacorrespondenceintheeffectsofmediacompositiononthesecretionoftheseenzymesandontheregulationofdevelopmentallycontrolledenzymesduringaxenicgrowth.Thesecretionoflysosomalenzymesthatarenotdevelopmentallyregulatedisaffectedinthesemedia,suggestingthattheregulationandsecretionoftheseenzymesareunderseparatecontrol.Itisclearthatstudiesoftheregulationoflysosomalenzymesinthisorganismmusttakeintoaccountthesecretionoftheenzymesaswellastheircellularspecificactivitiestoproperlyreflectlevelsofgeneexpression.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
