Balassa G, Milhaud P, Raulet E, Silva M T, Sousa J C
J Gen Microbiol. 1979 Feb;110(2):365-79. doi: 10.1099/00221287-110-2-365.
A Bacillus subtilis mutant is described which forms heat-resistant spores only in the presence of external dipicolinic acid (DPA). The mutation, dpa-1, is localized in a new sporulation locus, linked to pyrA. The dpa-1 strain is unable to synthesize DPA but can incorporate external DPA. The amount of DPA incorporated, the frequency of heat-resistant spores and their degree of resistance are all dependent on the concentration of external DPA. Spores of dpa- 1 strains exhibit normal resistance to most chemicals, including octanol and chloroform, but not to ethanol, pyridine, phenol and trichloroacetic acid. Complete resistance to the latter group depends on DPA. DPA incorporation is slow and apparently requires an energy supply but not protein synthesis. Direct involvement of DPA in the heat-resistance of the spores is suggested. Thin sections of DPA-less spores exhibit clearly visible cytoplasmic membranes and ribosomes. These structures are absent or less visible in the core of spores obtained with added DPA.
描述了一种枯草芽孢杆菌突变体，其仅在存在外部吡啶二羧酸（DPA）的情况下形成耐热孢子。该突变体dpa-1定位于一个新的孢子形成基因座，与pyrA连锁。dpa-1菌株无法合成DPA，但可以掺入外部DPA。掺入的DPA量、耐热孢子的频率及其抗性程度均取决于外部DPA的浓度。dpa-1菌株的孢子对大多数化学物质（包括辛醇和氯仿）表现出正常抗性，但对乙醇、吡啶、苯酚和三氯乙酸不表现出抗性。对后一组物质的完全抗性取决于DPA。DPA的掺入速度很慢，显然需要能量供应，但不需要蛋白质合成。提示DPA直接参与孢子的耐热性。不含DPA的孢子的超薄切片显示出清晰可见的细胞质膜和核糖体。在添加DPA后获得的孢子核心中，这些结构不存在或不太明显。
