Chemical and Morphological Studies of Bacterial Spore Formation

Abstract

From the stage of a completed membranous forespore to that of a fully ripened free spore, synchronously sporulating cells of a variant Bacillus cereus were studied by cytological and chemical methods. Particular attention was paid to the development of the three spore layers--cortex, coat, and exosporium--in relation to the forespore membrane. First, the cortex is laid down between the recently described (5) double layers of the forespore membrane. Then when the cortex is 1/~ fully formed, the spore coat and exosporium are laid down peripheral to the outer membrane layer covering the cortex. As these latter layers appear, the spores, previously dense by dark phase contrast, gradually "whiten" or show an increase in refractive index. With this whitening, calcium uptake commences, closely followed by the synthesis of dipicolinic acid and the process is terminated, an hour later, with the formation of a fully refractile spore. In calcium-deficient media, final refractility is lessened and dipicolinic acid is formed only in amounts proportional to the available calcium. If calcium is withheld during the period of uptake beyond a critical point, sporulating cells lose the ability to assimilate calcium and to form normal amounts of dipicolinic acid. The resulting deficient spores are liberated from the sporangia but are unstable in water suspensions. Unlike ripe spores, they do not react violently to acid hydrolysis and, in thin sections, their cytoplasmic granules continue to stain with lead solutions.

Nocturnal Production of Endospores in Natural Populations ofEpulopiscium-Like Surgeonfish Symbionts

“…Smaller intracellular offspring (Ͻ1 m in cross-sectional diameter) contained an electron-dense core, however most large offspring possessed cores with a mottled, lighter appearance. The electron-dense granular appearance of a spore core can be indicative of an immature or germinated spore, while mature endospore cores often have a poor affinity for stains and are more electron lucent (27,51). The nature of the white granular structures within the core is difficult to determine.…”

“…The DNA in rough, phase-bright cells is still accessible to small molecules (like DAPI) but protected from larger molecules such as DNase. Full refractility develops over time during the later stages of endospore development, coincident with cortex development and coat formation (51).…”

SPORULATION AND THE DEVELOPMENT OF RESISTANCE IN SPORING CULTURES OF CLOSTRIDIUM WELCHII

“…welchii forespores in Ellner cultures within 4-5 hr and that this was associated with increased resistance of these structures to hydrolysis. Young & Fitz-James (1959) noted forespore development in cultures of Bacillus cereus 1.i hr after cessation of growth. In the present investigation, forespore development in Cl.…”

“…ALTHOUGH much interest has been shown in bacterial spores there is still much to be learned about the process of sporulation (Young & Fitz-James, 1959). With only a few exceptions, most of the significant investigations of sporogenesis have involved studies of aerobic sporeforming bacilli.…”

Glycopeptide Synthesis During Sporulation of Bacillus Megaterium

“…According to earlier observations on n~orphological changes in sporulating bacilli (4, 5 , 10,21,22) and on the composition of the cortex of mature spores (17,18), synthesis of glycopeptide is a11 essential metabolic process of the vegetative cell that must occur during sporulation. At the time that this study was undertalien the extent of de novo synthesis of glycopepticle during sporogenesis, and the duratioil of this synthetic phase was not known.…”