Suppression by temperature of sporulation and of exocellular metalloproteinase synthesis in Bacillus megaterium

Abstract

Temperatures slightly supraoptimal for growth (above 40°C) delayed or inhibited the development of sporangia as well as the synthesis of metalloproteinase. The inhibition of sporulation was reversible and most of the cells sporulated and excreted proteinase when transferred to 35°C. The ability to synthesize the enzyme in a sporulation medium was maximal between 0.5–1.0 h of incubation at 35°C, between 0.5–2.0 h at 43.5°C and even later at 45°C. Proteinase formation was suppressed by temperature at the level of mRNA transcription.

Bacterial extracellular zinc-containing metalloproteases.

“…1). Protease production of B. megaterium was suppressed by temperature at the level of mRNA transcription and was associated with decreased sporangial development (125). The anticancer drug netropsin increased the formation of mRNA coding for the neutral metalloprotease of B. megaterium (33) but did not affect its repression by increased temperature.…”

Protein catabolism in growing Bacillus megaterium during adaptation to salt stress

“…Salt and heat stresses are similar in their e¡ects on the proteolytic apparatus in growing B. megaterium: (1) the extracellular proteinase production is strongly repressed by these stresses [20]; (2) the activity of ISP(s) is also signi¢cantly decreased by both stresses. The decrease of in vitro determined ISP activity contrasts with the stimulated catabolic activity during adaptation but corresponds well with the decrease in the degradation rate of LLP in exponential stressed culture.…”

Protein catabolism in growingBacillus megateriumduring adaptation to salt stress

“…Salt and heat stresses are similar in their effects on the proteolytic apparatus in growing B. megaterium : (1) the extracellular proteinase production is strongly repressed by these stresses [20]; (2) the activity of ISP(s) is also significantly decreased by both stresses. The decrease of in vitro determined ISP activity contrasts with the stimulated catabolic activity during adaptation but corresponds well with the decrease in the degradation rate of LLP in exponential stressed culture.…”