Improved method for determination of the position of double bonds in polyenoic fatty acid esters

An improved method is described for determination of the position of double bonds in polyenoic fatty acid methyl esters. Partial reduction with hydrazine is employed without prior hydrolysis to the free fatty acid, and the resulting monoenes are identified by reductive ozonolysis.

Oxidation of alkanes to internal monoalkenes by a Nocardia

A suspension of glucose-grown resting cells of Nocardia salmonicolor PSU-N-18 oxidized hexadecane to a mixture of internal monohexadecenes. The latter exhibited a cis configuration, and the mixture consisted of the following: 7-hexadecene, 80%; 8-hexadecene, 18%; and 6-hexadecene, 2%. Alkanes other than hexadecane also were unsaturated by the resting cells, and the composition of the monoalkenes resulting from octadecane dehydrogenation was 9-octadecene, 91%; 8-octadecene, 2 to 3%; 7-octadecene, 1 to 2%; and 6- and 5-octadecenes, trace amounts. Only minute quantities of unsaturated hydrocarbons accumulated during growth on hexadecane and during resting-cell incubation of hexadecane-grown cells with hexadecane. The dehydrogenation of hydrocarbons did not appear to be related to the formation of unsaturated fatty acids. It is postulated that double bond insertion may represent an early step in a new pathway of aliphatic hydrocarbon degradation.

New method for the reductive ozonolysis of double bonds in monoenoic fatty acid methyl esters

Unsaturated methyl esters were cleaved to aldehydes and aldehydo-esters by ozonolysis followed by reduction with dimethyl sulfide after conversion to hydroperoxides. Cleavage products were identified by thin-layer chromatography and quantified by temperature programmed gas-liquid chromatography.

The ginkgo, the most ancient living tree. The resistance of Ginkgo biloba L. to pests accounts in part for the longevity of this species

Fossil records clearly demonstrate that the group of trees known as Ginkgoales, of which today Ginkgo biloba is the sole living member, date back over 200 million years. Ginkgo bilboa itself is one of the oldest of living plants (4). It appears that the longevity of this tree and its long reproductive period are at least partially responsible for the persistence of the species. The resistance of these trees to pests such as insects, bacteria, viruses, and fungi has been studied. It is believed that their unusual resistance to pests accounts in part for the longevity of the trees and also, in turn, for the longevity of the species.

The stereochemistry of hexahydroprenol, ubiquinone and ergosterol biosynthesis in the mycelium of Aspergillus fumigatus Fresenius

1. The mycelium of Aspergillus fumigatus has been shown to incorporate mevalonate into squalene, ubiquinone, ergosterol and hexahydroprenol. 2. The (3)H/(14)C ratio in ubiquinone, biosynthesized from [2-(14)C-(4R)-4-(3)H(1)]mevalonate, is the same as in the squalene; essentially no (3)H was incorporated from [2-(14)C-(4S)-4-(3)H(1)]mevalonate, indicating the biosynthesis of biogenetically trans-isoprene units. 3. The (3)H/(14)C ratio for ergosterol (from ;4R-mevalonate') was 3:5, showing that the proton at C-24 is not lost during alkylation of the side chain; it probably migrates to C-25. 4. As (3)H from both mevalonates was incorporated into the hexahydroprenols the biosynthesis of both cis- and trans-isoprene units must occur. 5. The saturated omega- and psi-isoprene units are shown to be biogenetically trans, as are two of the unsaturated residues. 6. The saturated alpha- and unsaturated beta-isoprene residues are both biogenetically cis. 7. An inexplicable loss of approximately half of the olefinic protons from the cis-portion of hexahydroprenol occurs; possible reasons for this loss are discussed. 8. Increase in chain length of the hexahydroprenols is by a cis addition. 9. A biosynthesis of hexahydroprenols by addition of cis-isoprene units to all-trans-geranylgeranyl pyrophosphate, or a dihydro or tetrahydro derivative thereof, is suggested.

The characterization and properties of castaprenol-11, -12 and -13 from the leaves of Aesculus hippocastanum (horse chestnut)

The isolation and purification of a mixture of cis-trans-polyprenols from the leaves of Aesculus hippocastanum (horse chestnut) are described. Results of studies involving mass spectrometry, nuclear magnetic resonance, infrared spectroscopy, micro-hydrogenation and ozonolytic degradation show the mixture to be made up of undecaprenol, dodecaprenol and tridecaprenol with dodecaprenol predominating. Each of the prenols contains three trans internal isoprene residues and a cis ;OH-terminal' isoprene residue. They differ from each other only in the number of cis internal isoprene residues. The trivial names castaprenol-11, castaprenol-12 and castaprenol-13 are proposed to describe these compounds. Gas-liquid-chromatographic and reversed-phase partition thin-layer chromatographic evidence suggest the presence in the mixture of small quantities of castaprenol-10 also.