Cellular distribution and linkage of D-(-)-3-hydroxy fatty acids in Bacteroides species

Abstract

Two strains of Bacteroides asaccharolyticus and two strains of Bacteroides fragilis were analyzed for total fatty acid, total lipid fatty acid, and total bound fatty acid profiles. Extracted lipids and defatted cell residues were subjected to sequential alkaline and acid methanolyses to distinguish ester- and amide-linked fatty acids in each fraction. In the lipid fractions, all the ester-linked fatty acids were nonhydroxylated, whereas all of the amide-linked fatty acids were hydroxylated. In the nonextractable fractions, both hydroxy and nonhydroxy fatty acids were found in both ester and amide linkage, although hydroxy acids predominated. The fatty acid profiles of the bound fractions differed widely from those of the lipid fractions. Bound fatty acid represented approximately 10% of the total cellular fatty acids.

Relationship between Hydroxy Fatty Acids and Prostaglandin E2in Gingival Tissue

“…Virtually all other saponifiable complex lipids hold fatty acids in an ester linkage. Mayberry reported that all 3-OH iC 17:0 recovered in Bacteroides fragilis and Bacteroides asaccharolyticus lipids was amide linked (20); however, the specific class or classes of complex lipids holding 3-OH iC 17:0 were not identified in this report. Preliminary work has also shown that 20 to 70% of the 3-OH iC 17:0 in lipid extracts from isolates of Porphyromonas gingivalis, a suspected periodontal pathogen, is in an amide linkage (data not shown).…”

“…For determination of total hydroxy fatty acids, the remaining half of each tissue lipid extract was supplemented with 2 N HCl (0.5 ml) and heated overnight at 100°C (20). The sample was cooled, and 16 N KOH (0.37 ml) was added; this was followed by incubation at 100°C for 90 min.…”

“…Figure 1 shows the recovery of ester-linked and total hydroxy fatty acids in lipid extracts from gingival tissue and subgingival plaque samples. The difference between ester-linked and total hydroxy fatty acid recoveries represents the amide-linked hydroxy fatty acid content (20). Results for 14 gingivitis plaque samples and 40 adult periodontitis plaque samples and for 5 gingivitis tissue samples and 27 adult periodontitis tissue samples are shown.…”

Dihydroxy and monohydroxy fatty acids in Legionella pneumophila

“…In the nonextractable or bound fractions, the fatty acids appeared to be evenly divided between the ester-linked (alkali-labile) fatty acids, which were predominantly nonhydroxy acids, and the amide-linked (alkali-stable, acid-labile) fatty acids, which were predominantly hydroxy acids. The bound fatty acid fractions comprised approximately 10 mol% of the total cellular fatty acids, a situation not uncommon in bacteria (9,10).…”

Prostaglandin E release from human monocytes treated with lipopolysaccharides isolated from Bacteroides intermedius and Salmonella typhimurium: potentiation by gamma interferon

“…The fatty acid composition of each LPS preparation was determined by adding 3 jig of nonadecanoic acid (Sigma Chemical Co., St. Louis, Mo.) to LPS samples (1 mg) and then by hydrolysis in 4 N KOH (100°C, 4 h) (15,16). After adjusting the pH of hydrolysates to 1, free fatty acids were extracted with chloroform (three times, 1 ml each), and the pooled extracts were dried under N2 gas.…”