Wehrli E, Scherrer P, Kübler O
Eur J Cell Biol. 1980 Feb;20(3):283-9.
The comparative morphology of spores from Bacillus cereus, B. thuringiensis S-9 (wildtype), B. thuringiensis HB 9-1 (acrystaliferous mutant) and B. finitimus, was studied by the freeze-etching technique. Particular attention was given to the three crystalline layers found in these spores, the pitted layer, the parasporal layer, and the basal layer of the exosporium with lattice constants of 9.2 nm, 5.8 nm and 8.0 nm respectively. The parasporal layers, corresponding to the fraction of Fl of Scherrer and Somerville [18] were found to be membraneous sheets laying between spore and exosporium. Analysis of the isolated exosporium by negative staining and digital image processing revealed a lattice structure belonging to the p 6 hexagonal space group with a repeat of 8.0 nm. The unit cell contains 6 subunits, each 3 nm in diameter, which are centered around a hypothetical channel readily penetrated by the stain.
采用冷冻蚀刻技术研究了蜡样芽孢杆菌、苏云金芽孢杆菌S-9（野生型）、苏云金芽孢杆菌HB 9-1（无晶体突变体）和有限芽孢杆菌孢子的比较形态。特别关注了在这些孢子中发现的三层晶体层，即凹坑层、伴孢晶体层和芽孢外壁的基底层，其晶格常数分别为9.2纳米、5.8纳米和8.0纳米。与Scherrer和Somerville [18]的F1部分相对应的伴孢晶体层被发现是位于孢子和芽孢外壁之间的膜状薄片。通过负染色和数字图像处理对分离出的芽孢外壁进行分析，发现其晶格结构属于p 6六方空间群，重复距离为8.0纳米。晶胞包含6个亚基，每个亚基直径为3纳米，它们围绕着一个假设的易被染色穿透的通道居中。
