Comparative Study of Pressure- and Nutrient-Induced Germination of Bacillus subtilis Spores

Abstract

Germination experiments with specific germination mutants of Bacillus subtilis, including a newly isolated mutant affected in pressure-induced germination, suggest that a pressure of 100 MPa triggers the germination cascades that are induced by the nutrient germinant alanine (Ala) and by a mixture of asparagine, glucose, fructose, and potassium ions (AGFK), by activating the receptors for alanine and asparagine, GerA and GerB, respectively. As opposed to germination at 100 MPa, germination at 600 MPa apparently shortcuts at least part of the Ala-and AGFK-induced germination pathways. Inhibitors of nutrient-induced germination (HgCl 2 and N␣-P-tosyl-L-arginine methyl ester) also inhibit pressure-induced germination at 600 MPa, suggesting that germination at 600 MPa involves activation of a true physiological germination pathway and is therefore not merely a physico-chemical process in which water is forced into the spore protoplast.

Influence of Pressure on Germination of Garden Cress, Leaf Mustard, and Radish Seeds at Various Temperatures

“…Our results at 25˚C showed good agreement with those reported at 20˚C by Wuytack et al, [21] although there were minor differences in various experimental conditions between our experiments, as follows. 1) We pressurized seeds for 10 min, but Wuytack et al pressurized for 15 min; 2) we spread seeds on plates holding moistened filter paper, whereas Wuytack et al spread seeds on 1.2% agar plates; 3) the origin of the seeds was different.…”

“…Therefore, prior to evaluating the effect of pressure on reducing microbial counts, we need to examine the effects of high hydrostatic pressure and temperature on germination percentage and germination time. These parameters have been studied widely for spores [17][18][19][20][21][22], but rarely for seeds [9,14,15]. In particular, to the best of our knowledge, the effect of high hydrostatic pressure on seed germination at low temperature (4˚C, typical refrigerator temperature) has not been investigated.…”

Exploration of the Effects of High Hydrostatic Pressure on Microbial Growth, Physiology and Survival: Perspectives from Piezophysiology

“…48) Pressures of 100-300 MPa activate the nutrient receptors whereas higher pressures of 500-800 MPa release the Ca 2þ -DPA depot. 46,49,50) The results of these studies give new insight into the mechanism of spore germination as well as contributions to food processing technology by high-pressure treatment. Table 2 lists the occurrence of yeast physiology and survival under high hydrostatic pressure.…”

Disinfection of Human Tissues in Orthopedic Surgical Oncology by High Hydrostatic Pressure

“…The most efficient methods of inactivation are gamma irradiation and thermal inactivation as well as chemical sterilization methods such as the peracetic acid-ethanol treatment of bone (49). The direct effect of HHP to achieve killing of vegetative bacterial, yeast and mould cells, has been documented as well (50,51), although much higher pressure values of 500 -700 MPa are needed than for the inactivation of viruses (52,53). Interestingly, Gram-positive bacteria are more resistant to HHP than Gram-negative bacteria (54).…”