Metabolic Activities in Dormant Spores of Bacillus Species
Technical Report,01 Dec 2015,31 Mar 2019
University of Connecticut - Health Center Farmington United States
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The objectives of the proposed work are to determine parameters of metabolic activity in dormant spores of Bacillus species, and whether dormant spore metabolic activity alters spore properties such as resistance to heat and chemical agents, as well as ease of germination. Spores of Bacillus species as well as closely related Clostridium spores are major causes of food spoilage and food borne illness, as well as a number of serious diseases, largely because of these spores dormancy and resistance. It has long been accepted dogma that spores have no metabolic activity. However, this dogma was called into question by a 2012 paper Segev et al. 2012. Cell 148139-149 that provided evidence that there was massive rRNA and mRNA degradation as well as significant transcription in dormant Bacillus subtilis spores held at 37 or 50 deg C for 3-8 d. Our laboratory followed-up the Cell paper and found evidence of slow metabolic activity in spores stored at 37-50deg C, but only in spent sporulation medium, not during storage in water, and no ATP was detected. The current proposal seeks to extend this initial study much further to establish the magnitude of this metabolism and its effects on dormant spore properties, using primarily spores of B. subtilis and B. megaterium. The specific goals of the new research are as follows. 1 Identify and quantitate low mol wt catabolites in spores, including the levels of malate recently reported to be significant in spores. This analysis will utilize 13C- and 31P-NMR, as well as sensitive enzymatic assays for ATP. 2 For any new catabolites identified, determine the fate of such catabolites a during extended storage of spores at physiological temperatures and b during normal spore germination. 3 If malate is found in spores at high levels, the levels of enzymes involved in malate metabolism will be determined in dormant spores.
- Anatomy and Physiology