The main fatty acids of the lipids of Brucella abortus (strain Scherle 11, or 11 19) and of Brucellu melitensis (strain M-15) are palmitic acid, a C,, monoenoic acid an a C,, cyclopropane fatty acid. By chemical degradation, it is shown that the unsaturated C,, acid is cis-vaccenic acid. The C,, cyclopropane acid has been identified with lactobacillic acid, either by permanganate oxidation according to Murray, or by mass spectrometry of the keto-esters obtained by chromic acid oxidation.I n a preliminary note [l], we mentioned the presence of a C,, cyclopropane fatty acid in the nonesterified fatty acids of Brucellu abortus Bang. Later this acid was detected in various lipid fractions isolated from several strains of Br. abortus So far, no information has been given on the structure of this C,, cyclopropane fatty acid. We have now identified it with lactobacillic acid (1 1 ,lZ-methyleneoctadecanoic acid) (I), and we have shown that, in the lipids of Br. abortus as well as in those of Br. melitensis, it is accompanied by cis-vaccenic acid (cis-octadec-11, 12-enoic acid) (V).
MATERIAL AND METHODS
BacteriaBrucella abortus, strains Scherle I1 and I 119, was grown a t 37' on several types of culture media solidified with agar [3,6]. After approximately 70 h, the bacterial cells were harvested by washing the flasks with physiological sodium chloride solution.Brucella melitensis, strain M-15, was grown a t 37" on a solid medium containing peptone and glycerol, and harvested after 48 h of growth ["I.
