Title: Effects of High Pressure on Bacterial Spores
Abstract: High pressures (50 to 800 MPa) were found to inactivate spores many years ago. The killing of spores by pressure is unusual in that very high pressures are often less effective than are lower pressures. The initial germination may be essential for efficient spore killing by pressure, since germinated spores are much more sensitive to stress factors, in particular, heat, than are dormant spores. Consequently, in order to fully understand the effects of high pressures on spores, it is essential to first understand (i) the structure of dormant spores, (ii) some of the factors that contribute to spore resistance, and (iii) the normal mechanism(s) for germination of bacterial spores, as high-pressure germination uses some components of normal spore germination pathways. Spores of Bacillus and Clostridium species have a structure very different from that of growing cells, with a number of layers unique to spores and many spore-specific macromolecules. The nutrients that trigger germination vary in a species- and strain-specific manner, but common ones are L-amino acids, D-sugars, and purine nucleosides. Bacillus subtilis spores have three functional germinant receptors. The GerA receptor responds to L-alanine, while the GerB and GerK receptors together trigger germination with a mixture of L-asparagine (or L-alanine), D-glucose, D-fructose, and K+ ions. Dipicolinic acid (DPA) and other ions that are released early in germination comprise ~25% of the spore core's dry weight. Germination of spores of some strains, in particular, some Bacillus megaterium strains, is triggered by inorganic salts such as KBr.
Publication Year: 2014
Publication Date: 2014-04-30
Language: en
Type: book-chapter
Indexed In: ['crossref']
Access and Citation
Cited By Count: 5
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot