Levels of L-malate and Other Low Molecular Weight Metabolites in Spores of Bacillus Species and Clostridium difficile
Journal Article - Open Access
UConn Health Farmington United States
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Dormant spores of Bacillus species lack ATP and NADH and contain notable levels of only a few other common low mol wt energy reserves, including 3-phosphoglyceric acid 3PGA, and glutamic acid. Recently, Bacillus subtilis spores were reported to contain approx. 30 micronsol of L-malateg dry wt, which also could serve as an energy reserve. In present work, L-malate levels were determined in the core of dormant spores of B. subtilis, Bacillus cereus, Bacillus megaterium and Clostridium difficile, using both an enzymatic assay and 13C-NMR on extracts prepared by several different methods. These assays found that levels of L-malate in B. cereus and B. megaterium spores were 0.5 micronsolg dry wt, and 1 micronsolg dry wt in B. subtilis spores, and levels of L-lactate and pyruvate in B. megaterium and B. subtilis spores were 0.5 micronsolg dry wt. Levels of L-malate in C. difficile spores were or 1 micronsolg dry wt, while levels of 3PGA were approx. 7 micronsolg the latter value was determined by 31P-NMR, and is in between the 3PGA levels in B. megaterium and B. subtilis spores determined previously. 13C-NMR analysis of spore extracts further showed that B. megaterium, B. subtilis and C. difficile contained significant levels of carbonatebicarbonate in the spore core. Low mol wt carbon-containing small molecules present at 3 micronsolg dry spores are i dipicolinic acid, carbonatebicarbonate and 3PGA in B. megaterium, B. subtilis and C. difficile ii glutamate in B. megaterium and B. subtilis iii arginine in B. subtilis and iv at least one unidentified compound in all three species.