Early events during bacterial endospore formation.
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Bacillus↗
Biomedical subjects
J Mandelstam
Publications and source records attributed to J Mandelstam.
Extracellular manganese-stimulated deoxyribonuclease as a marker event in sporulation of Bacillus subtilis.
A considerable amount of Mn2+-stimulated DNAase (deoxyribonuclease) activity is released by Bacillus subtilis 168 during sporulation in a glucose-deficient medium; much smaller amounts are released during starvation for phosphate or nitrogen. Protein synthesis is required. Two forms of evidence are presented that production of the DNAase is associated with events late in stage II of sporulation. 19 Thymidine starvation, which inhibits the biochemical events associated with sporulation, also inhibits release of the DNAase. 2. Several asporogenous mutants blocked at stage II or earlier and unable to produce alkaline phosphatase (a stage-II event) do not produce the enzyme. Mutants blocked towards the end of stage II or later produce both enzymes. During sporulation of the wild-type strain, the DNAase appears about 1 h after alkaline phosphatase. The results suggest that production of the DNAase is controlled by a still-undiscovered stage-II genetic locus.
Bacillus subtilis↗
Cell polarity in Bacillus subtilis: effect of growth conditions on spore positions in sister cells.
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Bacillus subtilis↗
The Leeuwenhoek lecture, 1975: bacterial sporulation: a problem in the biochemistry and genetics of a primitive developmental system.
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Bacillus↗
Order of expression of genes affecting septum location during sporulation of Bacillus subtilis.
The mean volumes of stationary-phase cells of wild-type and asporogenous mutants of Bacillus subtilis have been measured. Mutants blocked at stage 0 of sporulation either produced cells that had the same volume as the developing sporangium or they divided to produce cells of one-half this volume. The order of expression of the genes affected by the mutations in these strains was determined by biochemical characterization and by construction of double sporulation mutants. Mutants that produced small cells were blocked at an earlier stage of sporulation than those that produced large cells. It is suggested that the following dependent sequence must occur before the formation of the prespore spetum: (i) the initiation of sporulation, (ii) a signal to block the final central division site, and (iii) a signal to activate a polar septum site.
Anti-Bacterial Agents↗
Resporulation of outgrowing Bacillus subtilis spores.
Germinated spores of Bacillus subtilis were incubated in outgrowth medium and tested periodically for capacity to sporulate when suspended in sporulation medium. Concurrent measurements were made of deoxyribonucleic acid (DNA) content and numbers of cell division septa and nucleoids. Sporulation potential is shown to reach a peak at about 110 min at which time the chromosomes are probably well into the second round of replication. Experiments with nalidixic acid show that sporulation potential can be generated in the outgrowth medium even when DNA synthesis is largely prevented. Further experiments show that nalidixic acid apparently does not prevent the formation of DNA initiation complexes, which can subsequently function after resuspension in the sporulation medium. The results support those previously obtained with a temperature-sensitive DNA mutant which indicated that sporulation could only be induced at a specific stage of chromosome replication, and then only if the cells are in a state of nutritional "step-down".
Bacillus subtilis↗
Production and possible function of serine protease during sporulation of Bacillus subtilis.
The production of extracellular protease during sporulation in Bacillus subtilis 168 was investigated. Two proteases are produced, an alkaline serine protease and a neutral metalloprotease. In vivo inhibition of the serine protease with phenylmethylsulfonylfluoride indicated that the metalloprotease was degraded by the serine protease during sporulation. The experiments with phenylmethylsulfonylfluoride also show that the serine protease is necessary for the sequential process of sporulation and that it is required continuously for the first 2 to 3 h of the 8-h process.
Alkaline Phosphatase↗
Criteria for categorizing early biochemical events occurring during sporulation of Bacillus subtilis.
Two criteria are suggested for assessing the relevance of biochemical events occurring early in sporulation. The first is thymidine starvation, a condition known to inhibit sporulation. This also inhibits the production of metalloprotease, serine protease, and ribonuclease; alpha-amylase production, however, is unaffected. The second is the effect of a regulator mutation which increases the production of the proteases. In the mutant, ribonuclease is produced in correspondingly large quantities whereas alpha-amylase production is unaffected. We conclude that, whereas the serine protease is part of the main sequence of events leading to formation of the spore, the metalloprotease is a side effect, i.e., connected with the main sequence but not part of it. Ribonuclease could, on present evidence, be either in the main sequence or a side effect associated with it. Amylase, however, seems to be separately regulated and neither directly nor indirectly connected with the sporulation sequence.
Alkaline Phosphatase↗