Bacterial spores are commonly isolated from a variety of different environments, including extreme habitats. Although it is well established that such ubiquitous distribution reflects the spore resistance properties, it is not clear whether the growing conditions affect the spore structure and function. We used Bacillus subtilis spores of similar age but produced at 25, 37, or 42°C to compare their surface structures and functional properties. Spores produced at the 25°C were more hydrophobic while those produced at 42°C contained more dipicolinic acid, and were more resistant to heat or lysozyme treatments. Electron microscopy analysis showed that while 25°C spores had a coat with a compact outer coat, not tightly attached to the inner coat, 42°C spores had a granular, not compact outer coat, reminiscent of the coat produced at 37°C by mutant spores lacking the protein CotG. Indeed, CotH and a series of CotH-dependent coat proteins including CotG were more abundantly extracted from the coat of 25 or 37°C than 42°C spores. Our data indicated that CotH is a heat-labile protein with a major regulatory role on coat formation when sporulation occurs at low temperatures, suggesting that B. subtilis builds structurally and functionally different spores in response to the external conditions.

中文翻译：

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枯草芽孢杆菌根据生长温度构建结构和功能不同的孢子。

细菌孢子通常是从各种不同的环境中分离出来的，包括极端的栖息地。尽管已经确定这种普遍存在的分布反映了抗孢子特性，但是尚不清楚生长条件是否会影响孢子的结构和功能。我们使用了类似年龄但在25、37或42°C下产生的枯草芽孢杆菌孢子，以比较它们的表面结构和功能特性。在25°C时产生的孢子疏水性更高，而在42°C时产生的孢子含有更多的二吡啶甲酸，并且对热或溶菌酶处理更具抵抗力。电子显微镜分析表明，尽管25°C的孢子有一层紧致的外层，但紧密地附着在内层上，而42°C的孢子却有颗粒状而不紧密的外层，让人联想到缺少蛋白质CotG的突变孢子在37°C下产生的皮毛。实际上，从25或37°C的被膜中提取的CotH和一系列依赖CotH的外壳蛋白（包括CotG）比42°C的孢子更丰富。我们的数据表明，CotH是一种不耐热的蛋白，在低温下形成孢子时，对外套的形成具有重要的调节作用，这表明枯草芽孢杆菌可根据外界条件构建结构和功能不同的孢子。