Chemical Composition and Heat Resistance of Some Aerobic Bacterial Spores

Abstract

WALKER, HOMER W. (Iowa State University of Science and Technology, Ames), JACK R. MATCHES, AND JOHN C. AYRES. Chemical composition and heat resistance of some aerobic bacterial spores. J. Bacteriol. 82:960-966. 1961.-Analyses of spores of Bacillus species for nitrogen, carbohydrate, dipicolinic acid, and phosphorus showed little correlation with heat resistance. However, as the molar concentration of magnesium increased in relation to dipicolinic acid and calcium concentrations, heat resistance generally decreased. Analyses of several batches of spores indicated that this relationship between calcium, magnesium, and dipicolinic acid did not always hold true. Therefore, while these materials apparently play an important role, other factors need to be included before a full explanation of thermal stability of spores can be made.

Endotrophic Calcium, Strontium, and Barium Spores of Bacillus megaterium and Bacillus cereus

“…megaterium QM B1551 did not discriminate between members of metal pairs furnished in equivalent concentrations (Table 2). This behavior resembles that of growth spores (1,27,31,48,52). The calcium uptake was only slightly reduced below what it was when furnished singly; the strontium and barium uptake, while also less, were nevertheless coaccumulated with calcium to a striking degree.…”

“…Spores contain large amounts of metal ions other than calcium (Tables 1 and 2; references 1,48,52,53). Most of the metals form chelates with DPA (47) and appear to be absorbed more or less concomitantly fro -n the medium.…”

“…Metal and DPA contents. Calcium usually is the predominant cation in spores harvested from conventional media (6), though not always (1,48,52). This may be merely the consequence of the relative abundance of metals in the sporulation environment.…”

Comparison of Survivor Curves of Bacillus subtilis Spores Subjected to Wet and Dry Heat

“…El-Bisi et al (1956) obtained wet heat survivor curves which were convex at low temperatures but linear at high temperatures. Other investigators found wet heat survivor curves which were concave (Alderton et al, 1964;Frank et al, 1957;Walker et al, 1961).…”

The Composition and Structure of Bacterial Spores

“…Studies on the composition of spores have been concerned with spore coat preparations (30,32,40), germination exudates (25,35), or specific constituents such as dipicolinic acid (DPA) (3,18,37), phosphorus fractions (7), or inorganic cations (4,37). The chemical composition of individual morphological components of the spore other than coat preparations has not been defined.…”