Ishii I, Takada H, Terao K, Kakegawa T, Igarashi K, Hirose S
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Cell Mol Biol (Noisy-le-grand). 1994 Nov;40(7):925-31.
Bacillus subtilis 168M contained a large amount of spermidine during the logarithmic phase of growth, but the amount decreased drastically during the stationary phase. The extracts, prepared from B. subtilis cells harvested in the logarithmic phase, contained activity of arginine decarboxylase (ADC) rather than the activity of ornithine decarboxylase. In the presence of alpha-difluoromethylarginine (DFMA), a specific and irreversible inhibitor of ADC, the amount of spermidine in B. subtilis during the logarithmic phase decreased to about 25% of the control cells. Under these conditions, spore formation of B. subtilis 168M delayed greatly without significant inhibition of cell growth. The decrease in spermidine content in the logarithmic phase rather than in the stationary phase was involved in the delay of sporulation. Electron microscopy of cells at 24 hrs. of culture confirmed the delay of spore formation by the decrease of spermidine content. Furthermore, the delay of sporulation was negated by the addition of spermidine. These data suggest that a large amount of spermidine existing during the logarithmic phase plays an important role in the sporulation of B. subtilis.
枯草芽孢杆菌168M在对数生长期含有大量亚精胺，但在稳定期其含量急剧下降。从对数生长期收获的枯草芽孢杆菌细胞制备的提取物含有精氨酸脱羧酶（ADC）的活性，而不是鸟氨酸脱羧酶的活性。在α-二氟甲基精氨酸（DFMA）（一种ADC的特异性不可逆抑制剂）存在的情况下，枯草芽孢杆菌对数生长期的亚精胺含量降至对照细胞的约25%。在这些条件下，枯草芽孢杆菌168M的孢子形成大大延迟，但对细胞生长没有明显抑制。对数生长期而非稳定期亚精胺含量的降低与孢子形成的延迟有关。培养24小时的细胞的电子显微镜检查证实了亚精胺含量的降低导致孢子形成延迟。此外，添加亚精胺可消除孢子形成的延迟。这些数据表明，对数生长期存在的大量亚精胺在枯草芽孢杆菌的孢子形成中起重要作用。
