Foerster H F, Foster J W
J Bacteriol. 1966 Mar;91(3):1333-45. doi: 10.1128/jb.91.3.1333-1345.1966.
Foerster, Harold F. (The University of Texas, Austin), and J. W. Foster. Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus. J. Bacteriol. 91:1333-1345. 1966.-Spores were produced by washed vegetative cells suspended in deionized water supplemented with CaCl(2), SrCl(2), or BaCl(2). Normal, refractile spores were produced in each case; a portion of the barium spores lost refractility and darkened. Thin-section electron micrographs revealed no apparent anatomical differences among the three types of spores. Analyses revealed that the different spore types were enriched specifically in the metal to which they were exposed during sporogenesis. The calcium content of the strontium and the barium spores was very small. From binary equimolar mixtures of the metal salts, endotrophic spores accumulated both metals to nearly the same extent. Viability of the barium spores was considerably less than that of the other two types. Strontium and barium spores were heat-resistant; however, calcium was essential for maximal heat resistance. Significant differences existed in the rates of germination; calcium spores germinated fastest, strontium spores were slower, and barium spores were slowest. Calcium-barium and calcium-strontium spores germinated readily. Endotrophic calcium and strontium spores germinated without the prior heat activation essential for growth spores. Chemical germination of the different metal-type spores with n-dodecylamine took place at the same relative rates as physiological germination. Heat-induced release of dipicolinic acid occurred much faster with barium and strontium spores than with calcium spores. The washed "coat fraction" from disrupted spores contained little of the spore calcium but most of the spore barium. The metal in this fraction was released by dilute acid. The demineralized coats reabsorbed calcium and barium at neutral pH.
福斯特，哈罗德·F.（得克萨斯大学奥斯汀分校）和J.W.福斯特。巨大芽孢杆菌和蜡样芽孢杆菌的内生钙、锶和钡芽孢。《细菌学杂志》91:1333 - 1345。1966年。——通过悬浮在补充有氯化钙、氯化锶或氯化钡的去离子水中的洗涤过的营养细胞产生芽孢。在每种情况下都产生了正常的、有折光性的芽孢；一部分钡芽孢失去了折光性并变黑。超薄切片电子显微镜照片显示这三种类型的芽孢在解剖学上没有明显差异。分析表明，不同类型的芽孢在孢子形成过程中特异性地富集了它们所接触的金属。锶和钡芽孢中的钙含量非常少。从金属盐的二元等摩尔混合物中，内生芽孢几乎以相同程度积累了两种金属。钡芽孢的活力明显低于其他两种类型。锶和钡芽孢具有耐热性；然而，钙对于最大耐热性是必不可少的。在萌发速率上存在显著差异；钙芽孢萌发最快，锶芽孢较慢，钡芽孢最慢。钙 - 钡和钙 - 锶芽孢很容易萌发。内生钙和锶芽孢在没有生长芽孢所需的预先热激活的情况下就能萌发。用正十二烷基胺对不同金属类型芽孢进行化学萌发的相对速率与生理萌发相同。钡和锶芽孢中热诱导的吡啶二羧酸释放比钙芽孢快得多。破碎芽孢的洗涤“外壳部分”含有很少的芽孢钙，但大部分芽孢钡。该部分中的金属可被稀酸释放。脱矿质的外壳在中性pH下重新吸收钙和钡。
