Occurrence of Cis-11,12-Methylene-Hexadecanoic Acid in the Red Alga Solieria pacifica (Yamada) Yoshida

Fatty acids in marine algae have attracted the attention of natural chemists because of their biological activity. The fatty acid compositions of the Solieriaceae families (Rhodophyceae, Gaigartinales) provide interesting information that unusual cyclic fatty acids have been occasionally found. A survey was conducted to profile the characteristic fatty acid composition of the red alga Solieria pacifica (Yamada) Yoshida using gas chromatography-mass spectrometry (GC-MS), infrared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). In S. pacifica, two cyclopentyl fatty acids, 11-cyclopentylundecanoic acid (7.0%), and 13-cyclopentyltridecanoic acid (4.9%), and a cyclopropane fatty acid, cis-11,12-methylene-hexadecanoic acid (7.9%) contributed significantly to the overall fatty acid profile. In particular, this cyclopropane fatty acid has been primarily found in bacteria, rumen microorganisms or foods of animal origin, and has not previously been found in any other algae. In addition, this alga contains a significant amount of the monoenoic acid cis-11-hexadecenoic acid (9.0%). Therefore, cis-11,12-methylene-hexadecanoic acid in S. pacifica was likely produced by methylene addition to cis-11-hexadecenoic acid.

Influence of Different Light Intensities on the Content of Diosgenin, Lipids, Carotenoids and Fatty Acids in Leaves of Dioscorea zingiberensis

Cultivation of the climbing plant Dioscorea zingiberensis at a light intensity of 100 μE · m-2 · sec-1 yields three different phenotypes. Most of the plants grow as green phenotype (DzW). Two further forms differ in their leaf shape and leaf color. Whereas one type exhibits a more pointed leaf shape in the upper part of the plant with leaves appearing yellow-green with white stripes or hatchings (DzY), the other type shows a more round leaf shape with an intensive yellow-green color (DzT). These three plant types differ in their diosgenin content not only in their rhizomes but also in the chloroplasts. In the rhizomes the diosgenin content in the green form is 0.4%, in the DzY-form 0.6% and in the DzT-form even 1.3% of the dry weight. Furthermore, even in chloroplasts of the green DzW-form and of the DzY-form the presence of diosgenin was demonstrated. It occurs there as the epimeric form yamogenin. The DzT-form contains no yamogenin in its chloroplasts. Besides this, these plant forms differ in their chlorophyll and carotenoid content and in their fatty acid composition. Carotenoids increase from 1.3% of total lipids in the green phenotype to 3.3% in the DzYand to 4.2% in the DzT-form. This increase refers to _-carotene as well as to lutein and neoxanthin. The chlorophyll content in the green type is 8.1% and lower in the DzY-form with 7%. The highest chlorophyll content is found in the DzT-form with 12%. Fatty acids in the DzY-form and in the DzT-form have a more unsaturated character than in the green phenotype. The content of the monoenoic acid trans-hexadecenoic acid is considerably lower in both phenotypes when compared to the green phenotype. In both phenotypes the quantity of fatty acids with 16 carbon atoms is reduced, whereas fatty acids with 18 carbon atoms occur in higher concentration. Cultivation of the green phenotype (DzW) at the three light intensities of 10, 100 and 270 μE · m-2 · sec-1 leads to changes of the diosgenin content in rhizomes, to an increase of leaf dry weight, to a reduction of the grana structure in chloroplasts and therewith to a decrease of the chlorophyll content. The total lipid content is highest under the cultivation at 100 μE · m-2 · sec-1 and reduced by 30% at 10 and 270 μE · m-2 · sec-1. Carotenoids, however, are highest in shaded plants (10 μE · m-2 · sec-1) and plants grown under high light conditions of 270 μE · m-2 · sec-1. At 100 μE · m-2 · sec-1 a decrease of saturated fatty acids is observed in comparison to plants grown under shaded conditions.

Influence of host diet on the concentrations of fatty acids in rumen bacteria from cattle

This study compared the effects of supplements (300 mL/day) of safflower oil (SO) on the long-chain fatty acid (LCFA) content and composition of rumen liquid-associated (LAB) and solid-associated bacteria (SAB) in two experiments: (1) Hereford steers fed lucerne hay (6 kg/day) and (2) Brahman steers fed low-quality hay (4 kg/day). Experiment 1: SO increased the concentrations of mono-unsaturated (MUFA) and polyunsaturated acids (PUFA) in bacteria without altering the concentrations of saturated acids (SFA). The concentrations of all classes of LCFA except PUFA were higher in SAB than in LAB. Variation in phospholidpid (PL) composition of bacteria in response to SO included lowered proportions of branched-chain (brFA) and odd-numbered acids. In steers fed hay alone, the neutral lipids (NL) of all bacteria consisted predominantly of SFA (90%). With SO supplement, SFA constituted 60% and trans-11 monoenoic acid 31% of NL. There were significant differences between LAB and SAB in the proportions of individual acids in PL and NL. Experiment 2: SO increased the concentrations of all classes of LCFA except brFA which were decreased. SO treatment decreased the proportions of all acids in NL, except 18: 0, 18 : 1 trans-1 1 and 18 : 2, which were increased. The results have demonstrated that the fatty acid content and composition of mixed rumen bacteria is dependent upon their nutrient supply.

Food particles as a site for biohydrogenation of unsaturated fatty acids in the rumen (Short Communication)

On incubation of linoleic acid with strained rumen contents from sheep, it was observed that conversion of linoleic acid into C18:1trans-11 monoenoic acid and subsequently into stearic acid was largely associated with the food-particle fraction. The bacteria, protozoa and cell-free supernatant together contributed less than 30% to the overall change in the added C18:2 fatty acid.

LIPIDS OF SERRATIA MARCESCENS

Cells of Serratia marcescens, whether pigmented or unpigmented, contained 10–11% of methanol–chloroform extractable lipids (dry weight basis) and < 1% of bound lipids. The extractable lipids contained 34–43% phosphatides, 3–11% unsaponifiable material, and 2–5% free fatty acid. The phosphatides contained high proportions of phosphatidyl ethanolamine and smaller amounts of phosphatidyl serine, polyglycerol phosphatides, phosphatidyl glycerol, and an unidentified ninhydrin-positive phosphatide probably associated with ornithine and other amino acids found in the lipid hydrolyzate.The fatty acids were found to consist largely of palmitic, C17- and C19-cyclopropane and C16- and C18-monoenoic acids. The proportions of monoenoic and cyclopropane acids were found to vary greatly with the age of the cultures; in the early stages of growth, regardless of pigmentation, low amounts of cyclopropane acids and high amounts of monoenoic acid were present, the latter being converted almost completely to cyclopropane acids during the active growth phase.The lipids associated with extracellular lipopolysaccharide material were similar in composition to the cellular lipids.