Lethal germination of spores ofBacillus megaterium 9885

Abstract

S L~K R Y . The ultrastructure of free spore coats of Bacillus megaterium 9885 was studied by exploitation of the spontaneous lysis of newly germinated spores in the presence of phosphate and absence of Ca*+, and the subsequent release of coat subunits. The subunits appeared as the middle layer of a sandwich. The primary size of the subunits was c. 20nm. Negative staining suggested the presence of peripheral charged groups (carboxyl?) surrounding a hexagonal-shaped subunit containing an acentric electron opaque spot ; where subunits had associated into monolayers, the peripheral rims disappeared but the number and position of subunits mas located from the acentric spots which remained visible. The newly germinated cell remained attached to the spore coat via a short connecting structure of amorphous material. Caa+ protected against lysis and also largely prevented coat disruption. Subsequent EDTA treatment did not produce the normal effects of Ca deficiency; instead, thin bridges of elastic material of apparently high tensile strength and remarkably uniform diameter were seen to connect neighbouring spore masses. The significance of these observations is discussed in relation to the luiown chemical composition of coats of related strains.

Effect of Lysozyme on Resting Spores of Bacillus Megaterium

“…The question naturally arises as to why the spores of B. megaterium ATCC 9885 undergo complete lysis when exposed to lysozyme. Others (4,12) have already demonstrated that complete lysis of the spores of this strain may occur with so-called physiological germinants. In complex mixtures of germinants, the presence of phosphate and of L-leucine was reported to be conducive to lysis, whereas calcium ions exerted a protective effect (12).…”

“…Others (4,12) have already demonstrated that complete lysis of the spores of this strain may occur with so-called physiological germinants. In complex mixtures of germinants, the presence of phosphate and of L-leucine was reported to be conducive to lysis, whereas calcium ions exerted a protective effect (12). Therefore, we have carried out preliminary experiments directed to this question of lysozyme-sensitivity of the spore central body.…”

“…Their dipicolinic acid and hexosamine content are in the usual range, 15% and 6.8%, respectively. They are reported to contain 1.8% calcium (12).…”

“…B. megaterium ATCC 9885 was obtained from the American Type Culture Collection (ATCC), Rockville, Md., in March 1963, and it has been maintained in our collection since that time. Its spore germination properties have been described 238 (12). B. megaterium strain Starka 899 (29) was obtained from J. Starka, Charles University, Prague, Czechoslovakia, and B. larvae UC 15 was obtained from G. M. Savage, The Upjohn Co., Kalamazoo, Mich.…”

Growth of Mycobacterium rhodochrous on n‐Decane: a New Growth Factor and Emulsifying Agent

“…It seems likely that a substance which scavenges ions from outside the cell, but which cannot be found cell free in any quantity except from stationary phase or disrupted cultures, may perform both extra-and intracellular functions which depend on efficient transport of the substance to and from the cell, thus distinguishing the biological from chemical chelating agents. Calcium is an important structural cation of cell walls (Humphrey & Vincent, 1966) and plays a vital role in preserving the integrity of the new vegetative cells of gmminated spores (Holdom & Foster, 1967). Calcium also is known to complex strongly with large protein molecules (Reithal, 1963).…”