Physiology of spores of mycobacillin producer and non-producer mutants ofBacillus subtilis
TL;DR: Spores of mycobacillin producer and non-producer mutants of Bacillus subtilis of identical genetic background have been studied with reference to germinating capacity, inhibition of germination, heat resistance and ion-exchange properties.
Abstract: Spores of mycobacillin producer and non-producer mutants ofBacillus subtilis of identical genetic background have been studied with reference to germinating capacity, inhibition of germination, heat resistance and ion-exchange properties. The spores are not physiologically equivalent.
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TL;DR: Sporulation was repressed in the parent strain by various carbon sources whereas glucose-resistant mutants were resistant to them but not to glycerol 2-phosphate, and the possible interrelationship between sporulation, dipicolinic acid and mycobacillin synthesis is discussed in light of these findings.
Abstract: Sporulation was repressed in the parent strain by various carbon sources whereas glucose-resistant mutants were resistant to them but not to glycerol 2-phosphate. Both mycobacillin and dipicolinic acid synthesis were repressed in the parent by some of the compounds tested,viz. glucose, pyruvate and glycerol 2-phosphate. However, these syntheses in the glucoseresistant mutants were not repressed by glucose and pyruvate but were repressed by glycerol 2-phosphate. The possible interrelationship between sporulation, dipicolinic acid and mycobacillin synthesis is discussed in light of these findings.
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263 citations
TL;DR: Intracellular turnover of protein was measured in wild-type Bacillus subtilis, which produces exoprotease at stage I in the sporulation process, and the same protease appears to be responsible both for the intracellular turnover and for extracellular proteolytic activity.
Abstract: 1. Intracellular turnover of protein was measured in wild-type Bacillus subtilis, which produces exoprotease at stage I in the sporulation process. Protein is degraded at a rate of 8–10%/hr. 2. As a result of this turnover, the proteins of the mother cell are extensively degraded and resynthesized by about 6hr., so that the later stages of spore formation occur in a cytoplasm containing mainly `new' protein. 3. The same protease appears to be responsible both for the intracellular turnover of protein and for extracellular proteolytic activity. In mutants that have lost the exoenzyme the intracellular protein is stable for many hours. In addition, these mutants fail to produce antibiotic and are asporogenous. When the exoprotease is regained as a result of back-mutation all the lost capacities of the cell are restored together. 4. Protease activity also accounts for the change in antigenic pattern of extracts of cells sampled during sporulation. Immunoelectrophoresis shows that, in the wild-type, the antigens characteristic of the vegetative cell have largely disappeared after a few hours; in the proteaseless mutants the vegetative-cell pattern is conserved. Apart from changing the protein pattern of the cell the protease could also have the function of removing protein inhibitors of sporulation. Other possible interpretations of the results are discussed.
92 citations
TL;DR: A strain of Bacillus subtilis, highly active against widely different groups of fungi, namely, skin pathogens, plant pathogens, rice-spoilage organisms, etc., was isolated.
Abstract: DURING the studies on the distribution of antifungal organisms in Indian fruits, vegetables and soils, a strain of Bacillus subtilis (characterized according to Bergey1), highly active against widely different groups of fungi, namely, skin pathogens, plant pathogens, rice-spoilage organisms, etc., was isolated2.
62 citations
TL;DR: Preexisting14C-DAP in vegetative cells ofBacillus cereus is not incorporated into the spores, but is released into the medium after sporogenesis is complete.
Abstract: The addition of different cysteine or thioproline concentrations (1–5×10−4M) to the culture at the outset of the formation ofBacillus cereus prespores, i.e. before the commencement of dipicolinic acid synthesis, led to the death of some of the cells and injured the thermoprotection mechanism of the surviving spores. In control spores with a high dipicolinic acid content, inactivation by heating at 85°C was preceded by a lag phase, while in cysteine- and thioproline-treated spores this lag phase was completely absent and the death rate of most of the spores (D-value=17) was actually higher than the final death rate of the control spores (D-value=33). A small proportion of the spores in inhibited cultures (less than 10%) displayed almost the same heat resistance as untreated spores. The heat sensitivity of treated spores was greater than might have been anticipated from their dipicolinic acid content. Their resistance to X-rays was not lowered, but was actually slightly raised. The results are discussed with reference to the differentiation of a possible “basal” and “additional” spore thermoprotection mechanism and to differentiation of the nature of heat and radiation resistance in bacterial spores.
58 citations
TL;DR: The time required for production of bacitracin has been shortened from 3 to 6 days to 24 hr., and a working hypothesis for the mechanism of biosynthesis of this polypeptide antibiotic has been proposed.
57 citations