Adenine Nucleotide Changes Associated with the Initiation of Sporulation in Bacillus subtilis

Abstract

At the end of the exponential growth phase of Bacillus subtilis, there is a decrease in the energy level of the cell, whether expressed as adenosine triphosphate concentration or adenylate energy charge. Phosphate limitation of exponentially growing cells produces a similar decrease in the energy level of the cell, and sporulation is derepressed in the presence of 10 mM glucose. A reduction in the tryptophan concentration of the medium during phosphate limitation of the tryptophan auxotroph B. subtilis 168 prevented the decrease in energy charge. Cells do not sporulate under these conditions. Energy charge values of 0.30 to 0.35 found during sporulation do not lead to cell death.Endospore formation in bacteria has been recognized as a response to a lack of nutrients since 1890 (2). Grelet (12) showed that sporulation of Bacillus megaterium occurred when on August 1, 2020 by guest

Genetic aspects of bacterial endospore formation.

“…It seems clear that sporulation requires an active system for producing ATP, and that the tricarboxylic acid cycle fills this role (88). It has also been reported that the end of exponential growth in B. subtilis is accompanied by a fall in the ATP level in the cell, which was shown to be transient in one report (88), but more prolonged in another (144). The latter authors showed that in all instances where ATP levels were maintained at the level found in growing cells, sporulation was prevented.…”

“…Mutants that are constitutive for its formation sporulate normally (209) so that premature synthesis of the enzyme does not interfere with spore formation. Phosphate starva-tion can trigger spore formation (111,144), but it is not possible to deduce from this any role for alkaline phosphatase. It is worth noting that spore formation is not triggered by phosphate limitation in continuous culture (60) where alkaline phosphatase is also derepressed.…”

Extracellular enzyme synthesis in the genus Bacillus.

“…licheniformis increases by only 75% during this period (181) possibly reflecting the relatively low rate of exoenzyme synthesis by this bacterium. There are no comparable figures for B. subtilis, but analysis of the ATP content of growing and sporulating cells reveals either a constant ATP level throughout the stationary phase when growing in nutrient sporulation medium (165) or a decline in ATP and energy charge on the depletion of glucose from minimal medium (133). This pattern contrasts the rise in ATP observed in B. amyloliquefaciens during this period (304) and may be responsible for the low rate of exoenzyme synthesis in B. subtilis.…”

“…These would be recycled to nucleoside triphosphates through successive phosphorylations. During stationary phase, the abrupt fall in the nucleotide triphosphate concentration in B. subtilis (133) would relieve the inhibition ofPDase II and allow the synthesis of 3'-mononucleotides and, subsequently, of free nucleosides. These products could be stored in the spore and be available for germination when a rapid RNA turnover occurs (290).…”

Intracellular adenylate pools and protein degradation during zoosporangial differentiation in Allomyces arbuscula

“…In the late 7O's, considerable attention was focused on the energy state of the celi as measured by the adenylate energy charge (see Atkinson 1977) and the regulation of energy metabolism. Hutchinson and Hanson (1974) observed a decrease in the ATP pool and in the adenylate energy charge during the initiation of sporulation in Bacillus subtitis. The very small variation of energy charge around 0.9 observed in our experiments (Fig.…”