Nutrient requirements of poultry

The chemical diversity and distribution of glucosinolates and isothiocyanates among plants

Brassinosteroids (BRs) are growth-promoting natural products found at low levels in pollen, seeds, and young vegetative tissues throughout the plant kingdom. Detailed studies of BR biosynthesis and metabolism, coupled with the recent identification of BR-insensitive and BR-deficient mutants, has greatly expanded our view of steroids as signals controlling plant growth and development. This review examines the microchemical and molecular genetic analyses that have provided convincing evidence for an essential role of BRs in diverse developmental programs, including cell expansion, vascular differentiation, etiolation, and reproductive development. Recent advances relevant to the molecular mechanisms of BR-regulated gene expression and BR signal transduction are also discussed.

BRASSINOSTEROIDS: Essential Regulators of Plant Growth and Development

This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption. The paper, which includes references published in 1981, is also intended to compliment existing reviews on the chemistry of these sulfur‐containing natural products. Particular emphasis is placed upon members of the Brassica family because of their importance as vegetables, condiments, oilseeds, and animal feedingstuffs. Since much of the work considered here relates to glucosinolate decomposition products, biochemical information concerning the nature, occurrence, and properties of the glucosinolate‐degrading enzyme, myrosinase, is considered in Section III. The methods available for the chemical analysis of glucosinolates and their various breakdown products are discussed critically. Factors affecting the glucosinolate content of plants and plant products arc outlined in Section VII. Particular emphasis is placed upon the effect of proces...

Glucosinolates and their breakdown products in food and food plants

https://www.mpipz.mpg.de/25701/Szekeres_Cell_85.pdf

Brassinosteroids Rescue the Deficiency of CYP90, a Cytochrome P450, Controlling Cell Elongation and De-etiolation in Arabidopsis

Extracts of Brassica napus L. (rape) pollen (family, Cruciferae) have been reported to produce a novel growth-promoting effect when applied to young pinto bean plants1,2. Fractions that are active in the bean second-internode assay3 give rise to both increased cell elongation and cell division4. The validity of these early reports has been questioned because biological activity was not correlated with any one pure compound5. Subsequently, we showed that isolation of the growth promoter was complicated by the presence of chromatographically similar, inactive components that were identified as 6-D-glucopyranosyl esters of long-chain fatty acids6. We now report the isolation, structure determination and biological activity of this new plant growth promoter, named (22R, 23R, 24S)-2α-3α,22,23-tetrahydroxy-24-methyl-6,7-s-5α-cholestano-6,7-lactone or brassinolide (Fig. 1).

Brassinolide, a plant growth-promoting steroid isolated from Brassica napus pollen

Silylation of hydroxyl groups in methyl esters of unsaturated hydroxy acids provides compounds that give mass spectra which can be readily interpreted, whereas spectra of underivatized esters are extremely difficult to evaluate. The relationship of the double bond(s) to the trimethylsiloxy (TMS) group results in specific mass spectral patterns. In esters that have the TMS group separated from the double bond by one methylene group, the ions caused byα-cleavage at the TMS group on the side closest to the olefinic group are much more abundant than those produced fromα-cleavage on the other side of the TMS group. In esters that have the TMS group and the double bond separated by two methylene groups,α-cleavage ions are approximately equal. When the TMS group and the double bond are allylic, no fragmentation results between them. Cleavage does occur on either side of this system, and those ions resulting from cleavage alpha to the TMS group are in greatest abundance. Silylation of esters that have a conjugated diene or ene-yne system adjacent to a hydroxyl group also gives derivatives amenable to gas chromatographymass spectrometry. In these esters, large peaks are observed that arise fromα-cleavage at the TMS group and at the other end of the olefinic system. No fragmentation between the TMS group and the sites of unsaturation occurs. Unsaturated epoxy methyl esters produce spectra difficult to interpret. When the epoxide is converted to methoxy-hydroxy derivatives by BF3-methanol, the spectrum locates the position of the epoxide group. Silylation of the hydroxyl group produces a compound that gives a less complicated spectrum which also locates the original epoxy group. Mass spectrometry of a series of unsaturated keto-esters, without derivatization, provides spectra that are easily interpretable.

Gas chromatography-mass spectrometry of methyl esters of unsaturated oxygenated fatty acids

Hydrolysis/autolysis of the glucosinolates found in wild and cultivated cruciferous plants can yield a variety of nitrogenous compounds for the alkyl or aryl moiety. These products include nitriles, isothiocyanates and oxazolidinethiones, all of which may present potential hazards in foods and feeds. More than 70 glucosinolates are known, and almost all the hydrolysis products are amenable to analysis by gas chromatography. The reaction can proceed in different ways, depending upon the conditions of hydrolysis or treatment of the plant during harvest or storage, and confirmation of the identifications made by retention data is sometimes needed. Gas chromatography-mass spectrometry can usually provide this additional structural information. Spectra of alkyl or aryl nitriles and isothiocyanates that contain other functional groups (hydroxyl, episulphide, methylthio, sulphinyl, sulphonyl) and oxazolidinethiones are presented and discussed.

Gas chromatography‐mass spectrometry of nitriles, isothiocyanates and oxazolidinethiones derived from cruciferous glucosinolates

Seed oils of the order Umbelliflorae, including those from the families Umbelliferae, Garryaceae, Araliaceae, Cornaceae, Davidiaceae, Nyssaceae and Alangiaceae, were analyzed for fatty acid composition by gas liquid chromatography (GLC) of their methyl esters. The characteristic fatty acid of the order, petroselinic acid, occurred in the Umbelliferae in amounts up to 85%. In the Araliaceae, the content was as high as 83% and in the Garryaceae as high as 81%. The other major acids were palmitic, oleic and linoleic acids, with small amounts of hexadecenoic, stearic, linolenic, and, in some cases, C20 acids. petroselinic acid was determined by microscale ozonolysis of the C18 monoenoic esters and subsequent GLC of the ozonolysis products. The occurrence of high oil contents (up to 46%) combined with exceptionally high (up to 83%) single component purity is notable and emphasizes the potential of the Umbelliflorae as a raw material source for the chemical industry.

Search for new industrial oils: XVI. Umbelliflorae—seed oils rich in petroselinic acid

Rapid separations of triglycerides by chain length and degree of unsaturation were made by high performance liquid chromatography (HPLC) on a C-18 μ-Bondapak column with acetonitrile-acetone solvent mixtures. For saturated triglycerides, a linear relationship was observed between the carbon number and the log of the retention volume. Each double bond present in the triglyceride decreased the retention volume to approximately that of a saturated triglyceride with two carbon atoms less. Correlations of the fatty acid composition, as determined by gas liquid chromatography (GLC) with the HPLC data, provides much additional insight about triglyceride composition. To calculate triglyceride compositions, an internal standard tripentadecanoin was added to collected fractions before analysis by GLC.

Gayland F. Spencer

Papers

Brassinolide, a plant growth-promoting steroid isolated from Brassica napus pollen

Gas chromatography-mass spectrometry of methyl esters of unsaturated oxygenated fatty acids

Gas chromatography‐mass spectrometry of nitriles, isothiocyanates and oxazolidinethiones derived from cruciferous glucosinolates

Search for new industrial oils: XVI. Umbelliflorae—seed oils rich in petroselinic acid

Triglyceride separation by reverse phase high performance liquid chromatography