. The cytology and life-history of bacteria. Bacteria. SURFACE STRUCTURES 4I E: THE SPORE COAT (23,60,81,82) The resistance of the bacterial spore to inimical agencies has been attributed by some authorities to the impermeable spore coat, and by others to the peculiar condition of the cytoplasm of the spore. While the spore coat is difficult to stain, it is no more so than the cell wall of vegetative bacteria, from which it docs not appear to differ markedly in any respect. Like the cell wall, the spore coat may be partially destroyed by hydrolysis with hydrochloric acid, and it is probably co
. The cytology and life-history of bacteria. Bacteria. SURFACE STRUCTURES 4I E: THE SPORE COAT (23,60,81,82) The resistance of the bacterial spore to inimical agencies has been attributed by some authorities to the impermeable spore coat, and by others to the peculiar condition of the cytoplasm of the spore. While the spore coat is difficult to stain, it is no more so than the cell wall of vegetative bacteria, from which it docs not appear to differ markedly in any respect. Like the cell wall, the spore coat may be partially destroyed by hydrolysis with hydrochloric acid, and it is probably composed mainly of polysaccharide material. Electron micrographs ot sections ot spores have shown that the spore coat is a single structure in Bacillus ccrciis, whereas in B. iiwoatciitini at least two layers can be discerned (Robinow, 1953). The ejection of the turgid nuclear material from hydrolyscd spores indicates that the spore coat possesses a small area ot weakness, possibly a germination pore. F: THE NUCLEAR MEMBRANE (5, 13, 14, 30) The apparent absence of a nuclear membrane in bacteria has many times been remarked upon in cytological literature. This is probably due to the fact that bacteria have been examined mainly in their period of active, vegetative growth, when the nucleus is permanently in the chromosomal condition. The resting nucleus has a membrane ot normal appearance. Electron micrographs of sections ot bacterial nuclei have shown signs ot a fibrous layer surrounding the denser portion of the nucleus. G; SLIME LAYERS AND CAPSULES (34, 56, 88, 92, 93, 94, 95, 96, 97, 98) Many bacteria possess a surface layer of mucoid material, and occasionally a well-defnied capsule. The two structures have often been confused, but ' are distinct and may be found Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectbacteria
