Formation Of Terpenes Research Articles

Formation of terpenes by yeasts during alcoholic fermentation

In the course of studies about the influence of various yeast species and strains on the formation of fermentation by-products, the ability of yeasts to biosynthesize terpenes and terpene derivatives was investigated. In model fermentations,Saccharomyces rosei, Kloeckera apiculata, Metschnikowia pulcherrima, andTorulopsis stellata formed trace amounts of the terpene hydrocarbonsβ-myrcene and limonene as well as the terpene alcohols linalool,α-terpineol, and farnesol. WithS. cerevisiae, only the formation of traces of farnesol could be established. These results clearly demonstrate that terpene patterns of various grape cultivars used in previous work for varietal classification of white wines are not influenced by yeast fermentation carried out according to modern enological methods.

Isolation of the sweet potato weevil factor causing terpene induction in sweet potato roots.

The larval homogenate of sweet potato weevil, Cylas formicarius, induced terpene formation in sweet potato root tissue. We indicated that the terpene-inducing factor of the larvae consisted of high molecular weight component(s) and low molecular weight component(s). The high molecular weight component(s) was heat-unstable and partially inactivated by pronase, indicating proteinacious properties. The low molecular weight components) was heat-stable.

Biosynthesis of terpenes: II. The site and sequence of terpene formation in peppermint

Experiments with 14CO 2 have shown that the synthesis of monoterpenes by peppermint occurs only in the young tissue, in leaves which are still expanding. The formation of the first terpenes in these young leaves is a rapid process, with several labeled terpenes formed in less than a half hour. Among these are unsaturated ketones; incorporation of the label into menthone takes somewhat longer; and several days are required to label the saturated alcohol menthol. Analysis of the distribution of terpenes through the leaf pairs of a single shoot shows a regular succession from unsaturated ketones and menthofuran in the young leaves to menthol and menthyl acetate in the old leaves. By using labeled terpenes as substrates with leaf slices, it is possible to demonstrate the conversion of piperitenone to piperitone, of pulegone to menthone, and of pulegone to menthofuran.

Analytical study of ipomeamarone & chlorogenic acid alterations in sweet potato roots infected by Ceratocystis fimbriata

Several nmetabolic alterations have been studied, from biochenmical and pathological viewpoints, in swveet potato roots infected by the black rot fungus, Ceratocystis fimibriata (2, 11, 13), among which the formation of ipomeamarone is of particular interest. Because this substance is a unique furanoterpenoid produced by host tissues in response to infection, and because it has remarkable biological properties, such as uncoupling and antipathogenic actions, elucidation of its biosynthetic mechanism would be of great value for the further study of terpene formation and of the host-parasite relationship. Furthermore, an increase of polyphenolic substances, e.g., chlorogenic acid, has been commonly observed in diseased plants (6, 10, 14), and some workers have implied that these play an important role in the defense mechanism, although contradictory evidence has been presented (5, 11). WVe have undertaken an analytical study of ipomeamarone and chlorogenic acid (3). However, recent chromatographic evidence (1) showing a concurrent formation of many ipomeamarone-like terpenoids in injured root tissues indicates the necessity of a more critical analysis of such metabolites in host tissues. The present paper deals with the quantitative analyses of ipomeamarone and chlorogenic acid in the infected root tissues of resistant and susceptible sweet potato varieties, and their possible role in the defense mechanism.

Terpene Formation in Pine from Mevalonic Acid

RECENT studies have demonstrated that mevalonic acid is a key intermediate in the biosynthesis of animal sterols1. Studies of the origin of triterpenes and carotenoids in soya bean and fungi indicate that these compounds may also be formed from acetate through mevalonic acid2. Although the incorporation of atmospheric carbon dioxide into pine terpenes has been demonstrated3, studies on the nature of the pathway by which these compounds originate have not been reported. In the present work, seedlings of Pinus attenuata were found to incorporate acetate-2-14C and mevalonic acid-2-14C into the monoterpenes. The turpentine of this pine is 98 per cent α-pinene4.

Polyisoprenes: A theory of the formation of terpenes and related compounds

AbstractA mechanism is presented which shows how terpenes and related compounds, some of which are found associated with trans—polyisoprene in nature, may be expected to be formed by a radical chain oxidative degradation of trans—polyisoprene.