linoleic-acid and 10-hydroxystearic-acid

The formation of hydroxystearic acid (HSA) and ketostearic acid (KSA) from oleic acid transformation has been documented in a variety of microbial species, including several isolated from the rumen of domesticated ruminant species. However, their ruminal production rates have not been established as influenced by fatty acid source. Dosing continuous cultures of mixed ruminal microorganisms with 1-(13C)-oleic acid increased the 13C enrichment of both HSA and KSA at 24 h postdosing, and showed that the majority (96 and 85%, respectively) of the HSA and KSA present in the 24-h samples originated from oleic acid. Several experiments using batch cultures of ruminal microorganisms showed that production of HSA and KSA was directly related to oleic acid input but was not affected by elaidic acid input, and that HSA was further metabolized to KSA but not to other fatty acids. When continuous cultures of ruminal microorganisms were supplemented with soybean oil or canola oil, production of 10-HSA + 10-KSA was related to oleic acid input but not to linoleic acid input. Daily production of 10-HSA + 10-KSA across treatments was 14.4 micromol/100 micromol oleic acid input into the cultures or 31.1 micromol/100 micromol oleic acid net loss. The results of this study quantify the formation of 10-HSA and 10-KSA from oleic acid transformation by ruminal microorganisms, and show that their accumulation in ruminal contents is directly related to the extent of oleic acid input and biotransformation by the rumen microbiota.

Topics: Animals; Carbon Isotopes; Cattle; Fatty Acids; Fermentation; Linoleic Acid; Oleic Acid; Rumen; Stearic Acids

A ruminal strain of Enterococcus faecalis was characterised with respect to its ability to hydrate oleic acid to 10-hydroxystearic acid. Hydroxy fatty acid was produced after growth had ceased and the carbon source was almost exhausted. Hydroxy fatty acid production was equally rapid whether the inoculum had been grown in the presence of oleic acid or not, and almost complete conversion was achieved when oleic acid was present at a concentration of up to 0.5% (v/v). Incubation under a hydrogen headspace did not result in biohydrogenation of oleic acid. In pH-controlled batch culture the proportion of oleic acid hydrated varied with the pH of incubation, with more hydration at lower pH. Growth was retarded in the presence of 0.1% (v/v) linoleic acid, inhibited by the same concentration of linolenic acid and did not result in the formation of hydrated products from these substrates. If this organism is able to transform oleic acid in the rumen then the only product likely to be formed is 10-hydroxystearic acid.

Topics: alpha-Linolenic Acid; Animals; Enterococcus faecalis; Hydrogen-Ion Concentration; Linoleic Acid; Linoleic Acids; Oleic Acid; Oleic Acids; Rumen; Stearic Acids

In the adipocere which is one of postmortem changes, some specific fatty acids possessing higher melting points together with soap play an important role in the formation of adipocere. These fatty acids were clarified to be mainly 10-hydroxystearic and 10-hydroxypalmitic acids. Moreover, slight amounts of 10-oxostearic and 10-oxopalmitic acids, which have higher melting points than those of hydroxy fatty acids, exist in the adipocere as well. The substantial adipocere is formed and stabilized by these specific fatty acids together with the soap. The hydroxy fatty acid (OHFA) and oxo fatty acid (OXOFA) are biosynthesized by some enzymes from bacteria. Various aerobic and anaerobic bacteria are involved in the formation of adipocere. For example, microbial conversion of various unsaturated fatty acids to 10-OHFA by Micrococcus luteus was investigated. As a result, 10-OHFA was synthesized only from fatty acids possessing cis-9-unsaturation. It was also clarified that 10-OHFAs were converted to the corresponding 10-OXOFAs but the 10-OXO compounds were inactive as substrates. Furthermore, the enzyme preparations from Flavobacterium meningosepticum solubilized by sonication catalyzed not only hydration of oleic acid to produce 10-hydroxystearic acid but also dehydrogenation of this product in the presence of deuterium. On the other hand, we found out that there was 10-hydroxy-12-octadecenoic acid (10-OHLA) from linoleic acid in some kinds of adipocere. 10-OHFA existing in adipocere has been thought not to exist in a living body. However, recently 10-epoxy-12-octadecenoic acid (leukotoxin, LTx) which is one of lipid peroxides was found not only in rice plants but in polymorphonuclear leukocytes. It was also clarified that these polymorphonuclear leukocytes produced the same 10-OHLA as the compound found in adipocere. Since LTx was found from leukocytes related to inflammatory response, it has been interested in involvement of not only the basic mechanism of biological defense but also the mechanism of shock as a vasoactive substance. A postmortem change itself is little associated with a phenomenon on a living body. However, 10-OHLA found in adipocere existed also in polymorphonuclear leukocytes, suggesting that this compound metabolized from LTx is closely related to a biological reaction.

Topics: Adipose Tissue; Chromatography, Gas; Fatty Acids; Humans; Linoleic Acid; Linoleic Acids; Neutrophils; Postmortem Changes; Soaps; Stearic Acids