Mode of Action of the Antibiotic Siccanin on Intact Cells and Mitochondria of Trichophyton mentagrophytes
Mode of Action of the Antibiotic Siccanin on Intact Cells and Mitochondria of Trichophyton mentagrophytes
复制标题
抗生素西卡宁对须毛癣菌完整细胞和线粒体的作用方式
作者：
K. Nose;A. Endo
Siccanin在3 μg/ml浓度下可完全抑制须癣毛癣菌的生长。Siccanin对T.须癣植物是末端电子传递系统中的琥珀酸脱氢酶。在50%生长抑制浓度（0.3 μg/ml）下，完整细胞的呼吸抑制比任何其他测试的细胞功能（包括细胞核糖核酸、脱氧核糖核酸、磷脂、蛋白质和细胞壁组分的合成）更强烈。此外，在相同浓度下，siccanin不会对细胞的渗透性造成任何可检测的损害。此外，线粒体制备物中琥珀酸的氧化比完整细胞中的呼吸对抗生素更敏感。其他底物的氧化测试是不太敏感的siccanin比琥珀酸。抗生素抑制磷酸化和氧化，而不引起P：O比率的变化。0.03 μg/ml的Siccanin可抑制线粒体琥珀酸氧化50%，但对无机磷（Pi）与三磷酸腺苷（ATP）的交换反应和二磷酸腺苷（ADP）与ATP的交换反应均无影响。ATP磷酸水解酶活性也对抗生素不敏感。然而，在非常高的浓度下，抗生素略微抑制Pi-ATP交换反应。根据这些结果，可以得出结论，siccanin通过抑制呼吸电子传递系统来抑制真菌生长。
Siccanin at 3 μg/ml completely inhibited the growth of Trichophyton mentagrophytes. The primary site of action of siccanin on T. mentagrophytes is succinate dehydrogenase in the terminal electron transport system. At a concentration of siccanin giving 50% inhibition of growth (0.3 μg/ml), respiration of intact cells was inhibited more strongly than any other cellular functions tested, including the syntheses of cellular ribonucleic acid, deoxyribonucleic acid, phospholipid, protein, and cell wall fractions. In addition, at the same concentration siccanin did not cause any detectable damage in the permeability of the cells. Furthermore, the oxidation of succinate in mitochondrial preparation is more sensitive to the antibiotic than respiration in intact cells. Oxidation of other substrates tested was less sensitive to siccanin than that of succinate. The antibiotic inhibited both phosphorylation and oxidation, without causing changes in the P:O ratio. Siccanin at 0.03 μg/ml, which caused 50% inhibition of succinate oxidation in mitochondria, had effect neither on the exchange reaction between inorganic phosphate (Pi) and adenosine triphosphate (ATP) nor on that between adenosine diphosphate and ATP. An ATP phosphohydrolase activity was also insensitive to the antibiotic. At very high concentrations, however, the antibiotic slightly inhibited the Pi-ATP exchange reaction. From those results, it was concluded that siccanin inhibits fungal growth by inhibiting the respiratory electron transport system.