title: Biochemical and electron microscopic observations of cytotoxic effect of a fraction from hemolytic streptococcus on Ehrlich ascites carcinoma cells.
abstract: A protein fraction (60-F), obtained from cell-free extract of living hemolytic streptococcus, Su-strain, by 50-60% saturation with ammonium sulfate, inhibited the de novo synthesis of nucleic acids and proteins in Ehrlich ascites carcinoma (EAC) cells. 60-F released RNA but not DNA from EAC cells. This cytotoxic or cytolytic effect of 60-F was substantiated morphologically by scanning and transmission electron microscopic (SEM and TEM) observations, showing that 60-F induced cellular changes such as a loss of microvilli, bleb formation, cell deformity and partial gap of cell membrane in EAC cells. In addition, it was found that 60-F was more stable in RPMI-1640 medium supplemented with fetal calf serum than in other various media examined and was sensitive to temperature, pH changes and trypsin digestion.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure; D003603:Cytotoxins / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004355:Drug Stability; D005260:Female; D051379:Mice; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D009705:Nucleosides / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D013291:Streptococcus / Q000032:analysis*
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D003603:Cytotoxins; D009705:Nucleosides; D012313:RNA; D004247:DNA