The Lecithinase of Bacillus cereus and its Comparison with Clostridium welchii  -toxin

Abstract

SUMMARY : Bacillus cereus and B. mycoides produce lecithinases which split lecithin into phosphorylcholine and a diglyceride in the same way as the lecithinase (a-toxin) of Clostridium welchii. These enzymes also possess most of the biological activities associated with Cl. welchii a-toxin, e.g. produce the Nagler reaction and the egg-yolk reaction, lyse red blood cells, and are dermonecrotizing and lethal.The enzymes are activated by Ca and Mg ions, but inhibited by Nay K, NH, ferric and Al ions. Optimal enzyme activity requires the presence of Ca ions within a narrow range of concentration of 1-4 x 1 0 -S~. It is interesting that at this concentration of Ca ion lecithin flocculates most readily from its emulsion. The enzyme thus seems to have a maximal affinity for lecithin when the latter adsorbs an optimal amount of Ca ion in reaching its isoelectric point.Like the Cl. welchii lecithinase, the B. cereus lecithinase is fairly resistant to heat. The lysis of red blood cells and the hydrolysis of free lecithin by B. cereus lecithinase was strongly inhibited by normal sera of all the animals tested. But when lecithin was bound in egg-yolk lipoproteins, its hydrolysis by the enzyme was unaffected by normal serum. Specific serum, on the other hand, was capable of inhibiting the hydrolysis of both free lecithin and protein-bound lecithin. The B. cereus and B. mycoides lecithinases are immunologically related, but they are not so related to Cl. welchii lecithinase.

Gas gangrene-like infection withBacillus cereus in a lymphoma patient

“…Originally, it was believed that these were due to one toxin, a lecithinase like the alpha-toxin of Clostridium perfringens. 5 T h e studies of Bonventre and Johnson, however, showed that Bacillus ceretis produces significant amounts of different enzymes: penicillinase, phospholipase, hemolysin, and a proteolytic enzyme.2 At least three of these will participate in the pathogenesis in man and animal. A lethal toxin effect was demonstrated i n a number of experimental animals after intravenous, intraperitoneal, and intranasal application.…”

Non-identity of the Phospholipase of Bacillus anthracis with the Anthrax Toxin

“…The hydrolysis of phospholipid by the enzyme may be dependent on the 'combined' state of the substrate in E.Y.B. It is relevant to point out here that lecithinase preparations from Bacillus cereus and Clostridium welchii, which hydrolysed equal amounts of free phospholipid, differed greatly in their ability to hydrolyse lipovitellenin (Chu, 1949). The phospholipase of B. mthracis resembles bacterial lecithinases in being fairly stable to heat and sensitive to surface denaturation.…”

“…In the case of lecithinase preparations from Clostridium welchii and Bacillus cereus, both the egg-yolk reaction and the toxicity are inhibited by the same homologous antiserum (MacFarlane, 1955;Chu, 1949 …”

Complex lipids of cells and spores of Bacillus polymyxa 1A39

“…They believed that neither of these explanations coaild account for the lyso compounds in £. cereus since Chu (1949) reported this organism contained phosphatidase D and not phosphatidase A. They were also unable to detect enol-ether linkages with the plasmal stain of Hack and Ferrans (1959)* In addition to the lyso compounds detected in bacterial lipids by others (Kates si âl», 1962), an additional lyso compound has been detected in the lipids of B. polymyxa.…”