Relation of the heat resistance of bacterial spores to chemical composition and structure II. Relation to cortex and structure

Abstract

The relation between the amount of cortex, measured as total hexosamine, as diaminopimelic acid and as muramic lactam, and the heat resistance of spores of five different strains of Bacillus stearothermophilus was studied. Electron micrographs of thin sections of the spores were made to relate the structure of the spores to chemical and thermal characteristics. It was found that the amount of the cortex was significantly related to heat resistance of the spores. Strains with more electron-dense and better organized cortices were found to express higher heat resistance.

Micro ecosystems from feed industry surfaces: a survival and biofilm study of Salmonella versus host resident flora strains

“…The lower diversity of genera observed at sites after heat treatment may indicate that certain strains have gained the ability to survive in defined feed production environments for long periods. The high presence of spore-forming strains within the genera Paenibacillus , Bacillus, Aneurinibacillus, Virgibacillus and Brevibacillus in post-heat treatment sites are likely to be caused by their documented heat resistance [33-37]. Although the environmental conditions in the fish feed processing plant (Plant A) could be characterized as being more humid compared to the animal feed processing plant (Plant B), the hygienic conditions of both feed plants were found to be similar.…”

Acyclic N-Halamine Coated Kevlar Fabric Materials: Preparation and Biocidal Functions

“…Bacillus subtilis spores (surrogate of anthrax spores) are known to be highly resistant to disinfections; spore coat, cortex, and inner protoplast have been identified as possible barriers against the attack of disinfectants. [22][23][24] With 0.26% of active chlorine content, the chlorinated PMAA-coated Kevlar fabrics killed 99% of 10 4 -10 5 cells/mL of the spores after 24 h of contact; with 0.65% of active chlorine, the fabrics provided a total kill of the same amount of the spores in 8 h; when the chlorine content was further increased to 1.0%, the minimum contact time for a total kill of the spores decreased to 2 h. To the best of our knowledge, this is the first example of Kevlar fabrics (one of the most widely used fabric materials in fire/ thermal protective clothing) that can inactivate not only gramnegative bacteria, gram-positive bacteria, and fungi but also viruses and spores. These unique characteristics make the coated Kevlar fabrics attractive candidates for a wide range of multipurpose protective applications.…”

Spore formation inBacillus subtilis

“…The coat's ability to protect the spore from enzymatic assaults has proven useful in resisting predation by bacteriophagous organisms like Tetrahymena (Klobutcher et al ., ; Laaberki and Dworkin, ). The cortex is believed to maintain the spore's partially dehydrated state (Imae and Strominger, ; Warth, ; Mallidis and Scholefield, ; Ulanowski and Ludlow, ), and this low water content is associated with resistance to heat (Slepecky and Foster, ; Koshikawa et al ., ; Beaman and Gerhardt, ). Other factors that contribute to heat resistance and reduction in spore water content include mineralization (Slepecky and Foster, ; Bender and Marquis, ; Marquis and Bender, ; Atrih and Foster, ) and the presence of the small molecule dipicolinic acid (DPA) (Paidhungat et al ., ; Setlow et al ., ).…”