Murakami S, Bodley J W, Livingston D M
Mol Cell Biol. 1982 May;2(5):588-92. doi: 10.1128/mcb.2.5.588-592.1982.
Diphtheria toxin kills spheroplasts of Saccharomyces cerevisiae but not the intact yeast cells. After 2 h of exposure to ca. 10(-7) M toxin, less than 1% of spheroplasts were able to regenerate into intact cells. The same high levels of toxin inhibited the rate of protein synthesis by more than 90% within 1 h, whereas RNA and DNA synthesis were not inhibited until 4 h or exposure. Both killing and protein synthesis inhibition were dependent on toxin concentration. The nature of the toxin-cell interaction was also studied by using fragments of intact toxin and mutant toxin proteins. Neither toxin fragment A nor CRM45 nor CRM197 affected spheroplasts, but CRM197 and ATP prevented the inhibitory action of intact toxin. These results suggest that toxin acts on S. cerevisiae spheroplasts in much the same manner as it acts on sensitive mammalian cells.
白喉毒素可杀死酿酒酵母的原生质球，但对完整的酵母细胞无效。在暴露于约10^(-7) M毒素2小时后，不到1%的原生质球能够再生为完整细胞。同样高浓度的毒素在1小时内可使蛋白质合成速率降低90%以上，而RNA和DNA合成直到暴露4小时才受到抑制。杀伤作用和蛋白质合成抑制均取决于毒素浓度。还通过使用完整毒素片段和突变毒素蛋白研究了毒素与细胞相互作用的性质。毒素片段A、CRM45和CRM197均不影响原生质球，但CRM197和ATP可阻止完整毒素的抑制作用。这些结果表明，毒素作用于酿酒酵母原生质球的方式与作用于敏感哺乳动物细胞的方式非常相似。
