Involvement of Methionine in Bacterial Lipid Synthesis

S-Adenosylmethionine in the Biosynthesis of Bacterial Fatty Acids

“…It has been shown that lactobacillic acid (cis-11 ,12-methylene-octadecenoic acid) is formed by the addition of a methylene group across the double bond of cis-vaccenic acid (cis-11 ,12-octadecenoic acid), and that the source of the added carbon atom is the methyl group of methionine (O'Leary, 1959a, b;Liu and Hofmann, 1962;Chalk and Kodicek, 1961). A similar mechanism has been suggested for the formation of C17 cyclopropane acid (O'Leary, 1959b;Law, 1961).…”

“…Perhaps the most noteworthy aspect of the fatty-acid composition of A. aerogenes is the high content of C17 cyclopropane acid. This acid has been detected in other microorganisms, including Escherichia coli (O'Leary, 1959b;Dauchy and Asselineau, 1960;and others), Bacillus subtilis and Pasteurella pestis (Asselineau, 1961), and Serratia marcescens (Zalkin and Law, 1962). Kaneshiro and Marr (1961) showed that the C17 cyclopropane acid in E. coli is cis-9, 10-methylene hexadecanoic acid, the homologue of 19-carbon lactobacillic acid.…”

“…The high content of the C17 acid in A. aerogenes and the ease with which this organism can be cultured in simple, welldefined media suggest that it mav be a convenient source of this compound. After initial studies had shown that methylcarbon from S-adenosylmethionine appeared in mixed fatty-acid fractions, it was expected, on the basis of experience with methionine (O'Leary, 1959b), that most of this methyl-carbon would be found in the cyclopropane acids. Studies of the individual acids showed that this was the case.…”

A Simple Procedure for Detecting the Presence of Cyclopropane Fatty Acids in Bacterial Lipids

“…Reports of lactobacillic acid (cis-1 1, 12-methyleneoctanoate) in lipids of Lactobacillus arabinosus (9), Lactobacillus casei (10), Agrobacterium tumefaciens (11), Escherichia coli (18), and Clostridium butyricum (8) were followed by detection of both lactobacillic and cis-9 , 10-methylenehexadecanoic acids in lipids of E. coli (14,21), A. tumefaciens (15), Serratia marcescens (2,16,17), and Aerobacter aerogenes (19).…”

Metabolism of cyclopropane fatty acids by Tetrahymena pyriformis

“…The structure was demon strated to be cis-ll,12-methyleneoctadecanoic acid (Hofmann, 1963). The occurrence of a cyclopropane fatty acid (CFA) in Escherichia coli was then reported (O'Leary, 1959a;Dauchy and Asselineau, i960) and it was proved to be cis-9.10methylenehexadecanoic acid by Kaneshiro and Marr (I96I). Lac tobacillic acid and an isomer cis-9.10-methyleneoctadecanoic acid or dihydrosterculic acid occur in Salmonella typhimurium (Gray,I962).…”