Immunochemical and immunohistochemical studies on the development of the cellular slime mold Dictyostelium mucoroides☆

[摘要] HyperimmuneserawereproducedinrabbitsagainstthesporesofD.mucoroides.Theheatedantiseraagglutinatedsporesaswellasvegetativeandinterphaseamebas,withnosignificantdifferencesintiters.Precipitinringtestsoftheantiserawithextractsofcellsatvariousstagesofdevelopmentindicatedamarkedincreaseinreactivityatthemigratingpseudoplasmodiumstageandafurtherincreaseatthesporestage.Twokindsofabsorptionstudieswereconductedandtheresultsindicatedthat(1)antigenicsubstance(s)whicharedifferentfromthesurfaceantigensarepresentinsidespores,andthattheybegintoincreaseinamountatthemigratingpseudo-plasmodiumstage;(2)newcombininggroupsaresynthesizedduringtheprocessofaggregation.Inordertostudylocalizationofantigensandcombininggroupsatvariousstagesofdevelopment,immunohistochemicalstudiesweremadebyusingfluorescein-conjugatedantisporesera,bothabsorbedandunabsorbed.Thestainingofthecellsurfacesindicatedthatthereisachangeinthesurfaceintheinterphase,thistakingplacesometimeaftertheamebashavefinishedfeeding.Thereafterthecellsurfaceremainsunchangeduntilthetimeofsporeformation.Thislatterchangeischaracteristiconlyofthesporesanddoesnotoccurinthestalkcells.Antibody-stainedcytoplasmicgranuleswereobservedatallstagesexceptthevegetativestage.Duringinterphase,cellsbegintosynthesizenewcombininggroup(s)inoroncertaingranulesinthecytoplasm.However,sincetheextentofthesynthesisvariesconsiderablyfromonecelltoanother,thecellpopulationbecomesconsiderablyheterogeneouswithrespecttotheamountofthecombininggroupstheycontain.Afterthesevariouscellsarecollectedrandomlybytheprocessofaggregation,thecellvariationalreadypresentisfurtheraccentuatedbythesynthesisofnewcombininggroupsinsomeofthecellsintheaggregationcenter.Thecellvariationintheaggregationcenterseemstoprovideabasisforthesortingoutofcellsintheformationofthemigratingpseudoplasmodium.Afterthecellsarerearranged,differentiationtakesplaceaccordingtotheirlocationwithinthemigratingpseudoplasmodium.Cellsintheanteriorregionlosecombininggroups,whiletheyincreaseinthecellsoftheposteriorregion.Thesignificanceofthecellsortinginthenormaldevelopmentofthecellularslimemoldswasdiscussedandcomparedwiththedevelopmentofanimalembryos.

[学科分类] 生物科学（综合）