Dehydration partitioned within core protoplast accounts for heat resistance of bacterial spores

Abstract

Water distributed unequally within the dormant bacterial spore was quantified for the first time by use of three different lysozyme‐sensitive morphotype spores of Bacillus megaterium. The extent of protoplast dehydration (27−29 g water/100 g wet protoplast) was sufficient to account for the heat resistance of such spores.

Influence of Glutamate on Growth, Sporulation, and Spore Properties ofBacillus cereusATCC 14579 in Defined Medium

“…Fermentation conditions and inoculation were as described before (14). The spores were harvested and washed as described previously and were stored in 10 mM KPO 4 , pH 7, with 0.1% Tween 80 to prevent clumping and attachment of spores to plastic laboratory equipment. The addition of Tween 80 had no effect on spore heat resistance.…”

“…In YLLG, but not in YLHG, NH 4 ؉ was taken up by the cells during sporulation. The total amount of nitrogen used by the bacteria in YLLG was less than that used by the bacteria in YLHG, although a significant amount of NH 4 ؉ was present in the medium throughout sporulation. Despite these differences, growth and temporal expression of key sigma factors involved in sporulation were parallel, indicating that the genetic time frames of sporulation were similar under both conditions.…”

“…The consumption of glutamate depended on the initial concentration; in YLLG, all of the glutamate was used early during exponential growth, while in YLHG, almost all of the glutamate was used during sporulation. In YLLG, but not in YLHG, NH 4 ؉ was taken up by the cells during sporulation. The total amount of nitrogen used by the bacteria in YLLG was less than that used by the bacteria in YLHG, although a significant amount of NH 4 ؉ was present in the medium throughout sporulation.…”

“…Sporulation started and was completed while significant amounts of carbon and nitrogen sources were still present in the medium, indicating that starvation was not the trigger for sporulation. Analysis of amino acids and NH 4 ؉ in the culture supernatant showed that most of the nitrogen assimilated by the bacteria was taken up during sporulation. The consumption of glutamate depended on the initial concentration; in YLLG, all of the glutamate was used early during exponential growth, while in YLHG, almost all of the glutamate was used during sporulation.…”

Mechanical Analysis of the Injury of Spores by Reciprocal Pressurization

“…4). Here, the water contents of spores generally ranged from about 25 to 55% (Black & Gerhardt, 1962;Grecz et al, 1970;Beaman et al, 1982;Beaman et al, 1984;Nakashio & Gerhardt, 1985;Hachisuka, 1988) and water contents of germinated spores are generally indicated about 75 to 85% (Black & Gerhardt, 1962;Grecz et al, 1970;Beaman et al, 1982). In this analysis, water content of ungerminated spores was assumed to be 40% and that of germinated spores 80%.…”