Setlow P
Department of Biochemistry, University of Connecticut Health Center, Farmington 06030, USA.
Annu Rev Microbiol. 1995;49:29-54. doi: 10.1146/annurev.mi.49.100195.000333.
The DNA in dormant spores of Bacillus subtilis as well as other Bacillus species is extremely well protected against damage resulting from treatments such as desiccation, heat, oxidizing agents, and UV and gamma radiation. This high degree of DNA protection is a major factor in the survival of spores of these species, not only when subjected to the treatments noted above, but also when incubated under common environmental conditions for many years. Factors that play major roles in overall spore resistance include the low permeability of spores to toxic chemicals and the decreased spore-core water content. However, although decreased spore permeability and water content appear to at least partially protect spore DNA from oxidative damage, these factors seem to play little or no role in protecting spore DNA from heat damage. The major factor preventing damage to spore DNA is the saturation of this DNA with a novel group of small, acid-soluble proteins of the alpha/beta-type whose binding greatly alters DNA's chemical and enzymatic reactivity as well as its UV photochemistry. Binding of these proteins is also a key factor in spore DNA resistance to desiccation, heat, oxidizing agents, and UV radiation.
枯草芽孢杆菌以及其他芽孢杆菌属物种的休眠孢子中的DNA，对于诸如干燥、加热、氧化剂、紫外线和伽马辐射等处理所造成的损伤具有极强的保护作用。这种高度的DNA保护是这些物种孢子存活的一个主要因素，不仅在遭受上述处理时如此，而且在常见环境条件下培养多年时也是如此。在总体孢子抗性中起主要作用的因素包括孢子对有毒化学物质的低渗透性以及孢子核心含水量的降低。然而，尽管孢子渗透性和含水量的降低似乎至少部分地保护了孢子DNA免受氧化损伤，但这些因素在保护孢子DNA免受热损伤方面似乎作用甚微或不起作用。防止孢子DNA受损的主要因素是该DNA被一组新的α/β型小的酸溶性蛋白质饱和，这些蛋白质的结合极大地改变了DNA的化学和酶促反应性以及其紫外光化学性质。这些蛋白质的结合也是孢子DNA抗干燥、加热、氧化剂和紫外线辐射的关键因素。
