Ultrastructure of differentiating oocytes in the trematode Gorgoderina attenuata: I. The “nucleolus-like” cytoplasmic body and some lamellar membrane systems☆

[摘要] Gorgoderinaattenuata,digenetictrematodes,wereremovedfromtheurinarybladderofRanapipiensandfixedineitheraceticacidalcohol,1:3,forlightmicroscopyorin2%osmiumtetroxide,phosphatebufferedtopH7.4,forelectronmicroscopy.ExtractionwithRNaseandstainingwithAzureBatpH4.0wereusedtoidentifyRNA.Alarge,dense,RNA-containing,“nucleolus-like”bodywasfoundinthecytoplasmofoocytesinthediffusediplotenestageofthefirstmeioticprophase.Thisbodyincreasedinsizeanddensityastheoocytedifferentiated.Itbegantobreakdownaftertheoocytehadlefttheovaryandatthetimewhenfertilizationoccurred.Electronmicroscopicobservationsshowedthisbodytobeprimarilycomposedofdenselypacked150–200Å“ribosome-like”particlessimilartothoseseeninthenucleolus,andlikethenucleolusthisstructurewasnotboundedbyamembrane.Thenumberandcomplexityofmembranestructuresinthecytoplasmincreasedduringdifferentiationoftheoocyte.Someideasconcerningtheoriginofthe“nucleolus-like”body,howitisformed,anditsfunctionarediscussed.

[学科分类] 生物科学（综合）