The Journal of Biochemistry
Online ISSN : 1756-2651
Print ISSN : 0021-924X
Role of Outer Coat in Resistance of Bacillus megaterium Spore
Tsutomu NishiharaYoshihiro TakuboEtsuko KawamataTomihiko KoshikawaJunji OgakiMasaomi Kondo
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1989 Volume 106 Issue 2 Pages 270-273

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Abstract

The outer coat fraction (OC-Fr) of Bacillus megaterium ATCC 12872 spore was isolated as a resistant residue after alkali extraction, sonic treatment, and pronase digestion of the spore coat preparation, and its backbone structure was determined by chemical analysis to be composed ofgalactosamine-6-phosphate (Ga1N-P) polymers with polypeptides and calcium.OC-Fr was not fully solubilized after ordinary acid hydrolysis. OC-Fr was insensitive to all hexosaminidases tested, and moreover, an isolated fragment, a pentamer ofGa1N-P, was also resistant to lysozyme and hexosaminidases even after N-acetylation, being sensitive to them to some extent after dephosphorylation. Molecular sieving experimentsrevealed that the outer coat limited the entry of compounds with a molecular weight of more than 2, 000. Exchange of the metal on the spore surface also influenced the heat resistance. Spores of0C-Fr-deficient mutants were less resistant but were still much more resistant than the vegetative cells. These results suggest that the outer coat protects the contents of the spore against chemical, physical and enzymatic treatments owing to the chemical structure itself, composed mainlyofGa1N-P polymers, and the molecular sieving effect.

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© The Japanese Biochemical Society
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