ISSN:
1745-4565
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Changes in the ultrastructure of Staphylococcus aureus 196E during heating at 50°C in 0.1 M phosphate buffer, and during repair in nutrient medium were studied using transmission electron microscopy. Injury was assessed by differential plating on tryptic soy agar (TSA) + 1% pyruvate and on TSA + 7% NaCl. Injury was 〉 99% in the first 15 min. Mild aldehyde fixation or osmium tetroxide fixation gave good cellular preservation. The observation of ribosome-free areas in all heated cells at all times (≥15 min) of injury is consistent with published reports that rRNA destruction is a primary locus of injury in heated bacteria. Cells heated 45 min or longer, as well as cells starved 1–2 h in buffer at 35°C, generated a variety of internal membranes, typically near the DNA region. At 90 and 120 min, extreme alterations of structure were apparent indicators of cell death. Cells heated 90 and 120 min had virtually no ribosomes, exaggerated internal membranes, and surface blebs. During repair of cells injured 30 min, the population assumed normal appearance in 4 h, although some cells clearly were incapable of repair. After 6 h, the number of cells undergoing division increased. The reappearance of normal ultrastructure paralleled regaining of salt tolerance in the culture.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1745-4565.1983.tb00466.x
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