Lytic enzyme-assisted germination of Bacillus anthracis and Bacillus subtilis spores.

Abstract

The goal of this work was to determine conditions under which external application of a spore germination-specific lytic enzyme (GSLE) can increase the germination efficiency of spore populations. The Bacillus anthracis GSLE SleB was applied to native and coat-disrupted B. anthracis and Bacillus subtilis spores. SleB was inactive on native spores but was able to trigger rapid germination of coat-disrupted spores. Using spores lacking their GSLEs or their germinant receptors to model poorly germinating spores, SleB application was able to increase colony-forming efficiency 100-fold for native spores and >1000-fold for coat-disrupted spores. SleB effects on GSLE-deficient spores were greater than on germinant receptor-deficient spores. SleB treatment can increase spore germination efficiency. The greater effect of SleB on coat-disrupted spores is presumably due to the greater access afforded to the cortex. However, SleB apparently gained access to the cortex of native spores after they responded to nutrients and completed stage I of germination, which may result in the disruption of coat structure. Treatment of spore populations with a GSLE can increase germination efficiency. Such a treatment might be utilized to increase the rapid activation of industrial spore-based products.