Interfering mechanism of sodium bicarbonate on spore germination of Bacillus stearothermophilus

Abstract

ND S .Q . S U N. 1998. Spore germination of Bacillus stearothermophilus was progressively inhibited as the concentrations of sodium bicarbonate (NaHCO 3 ) in the germination media increased from 0% to 1·0% (w/v). The inhibitory effect of NaHCO 3 was attributed to the release of HCO − 3 and its alkaline properties, each of which played a different role. At low concentrations (³ 0·3%), the inhibitory effect of NaHCO 3 was mainly due to bicarbonate. As NaHCO 3 increased from 0·3% to higher concentrations, the effect of HCO − 3 reached a plateau while the alkalinating effect became the more dominant inhibitory factor. Fourier transform infrared (FTIR) analysis reveals that sodium bicarbonate reacted with the carboxyl group (1570 cm −1 ) of some acidic amino-acid residues of protein in the spore, leading to a less orientated structure. A shift of two units towards the longer frequency for carboxyl groups indicates that a stronger interaction was formed between the carboxyl group and the Na ¦ ion. The largest ratio of peak height between the absorbance of carboxylate (1570 cm −1 ) and of amide II (1546 cm −1 ) of spores after pretreatment with 0·3% sodium bicarbonate reflects the biggest structural alterations of keratin-like proteins in the spore. The role of NaHCO 3 in enhancing the sporicidal effect of glutaraldehyde is discussed.

Real-time monitoring of Bacillus subtilis endospore components by attenuated total reflection Fourier-transform infrared spectroscopy during germination

“…The band near 1443 cm-l demonstrates the existence of an acid peptide, most probably glutamate and 3-phospho-~-glycerate (Helm & Naumann, 1995). The absorption peak at 1082 cm-l was attributed to the ring vibrations of polysaccharide (Cheung et al, 1998).…”

“…1. Decreases in optical density are indicative of the proportion of spores that have germinated (Cheung et al, 1998). As shown by the extent of phase-darkening, spores of the germination mutants were slower to germinate than the wild-type (Moir, 1992).…”

“…& Brown, 1985;Jenkinson, 1988;Preston & Douthit, 1989;Moir & Smith, 1990;Johnstone, 1994;Moir et al, 1994;Kuhn et al, 1995;Cheung et al, 1998). Some quantifiable events during germination, such as the loss of heat resistance, the release of DPA and hexosamine-containing cortex fragments, and the change from phase-bright to phase-dark under a phasecontrast microscope, have been described.…”

“…Germination of the spore suspensions was monitored by measuring the decrease in OD,,, (Cheung et al, 1998). Once the spores were mixed with nutrient broth, germination was monitored at 37 "C and at room temperature (20 "C) by measuring OD,,, at 5 min intervals over a 60 min period.…”

Influence of Oxygen Transmission Rate of Packaging Film on Outgrowth of Anaerobic Bacterial Spores

“…As in this study, it appears that once hermetically sealed, given appropriate conditions, germination and outgrowth may occur within a certain time frame, but beyond a certain point, germination either ceases to occur or does not occur at all. Studies on spore germination has focused on performance of sanitizing processes (Mills et al, 1998;Santos and Zarzo, 1997;Welt et al, 2001;Welt et al, 1994), post-treatment cooling times and handling (Nissen et al, 2002;Juneja and Marks, 1999;Stringer et al, 1997), media formulation and/or genetic markers related to germination (Alberto et al, 2003;Broussolle et al, 2002;Cheung et al, 1998;Dromigny et al, 1997). Generally, these studies tended to involve tightly controlled environmental conditions.…”