Henry W. Kircher

Unique Sterol in the Ecology and Nutrition of Drosophila pachea

Drosophila pachea, which breeds only in the stems of senita cactus (Lophocereus schottii) throughout the Sonoran Desert, requires the cactus as a dietary supplement when reared on laboratory media. Δ7-Stigmasten-3β-ol, isolated from the cactus or synthesized, can replace the cactus in the diet of flies reared nonaseptically or axenically. Δ7-Cholesten-3β-ol and Δ5, 7-cholestadien-3β-ol could be substituted for the cactus sterol; Δ5, 7-stigmastadien-3β-ol produced infertile females. Cholesterol, 4α-methyl-Δ7-cholesten-3β3-ol, β-sitosterol, stigmasterol, ergosterol, and Δ7-ergosten- 3β-ol did not support larval growth.

Senita cactus alkaloids: Their significance to Sonoran Desert Drosophila ecology☆

Abstract The toxicity of senita cactus (Lophocereus schotti), and the alkaloids derived from it, pilocereine (I) and lophocereine (II), have been tested against Drosophila pachea and eight other species of Drosophila of the Sonoran Desert. The cactus and pilocereine kill the adults and/or progeny of all species but D. pachea. The alkaloid is probably the main reason why no other species than D. pachea breeds in the rotting stems of senita cactus.

The role of phytosterols in host plant utilization by cactophilicDrosophila.

The Cactus-Drosophila Model System of the Sonoran Desert consists of four endemic species ofDrosophila (D. mojavensis, D. nigrospiracula, D. mettleri andD. pachea) and five species of columnar cacti (agria, organpipe, saguaro, cardón and senita). Extensive collection records indicate that each cactus species has only one species ofDrosophila as the primary resident. The elimination of six of the twenty possible random combinations ofDrosophila species and cactus species can be attributed directly to phytosterols.Drosophila pachea has a strict requirement for Δ7-sterols such as 7-cholestenol and 7-campestenol. Since Δ7-sterols are found only in senita cactus,D. pachea cannot use agria, organpipe, saguaro or cardón as host plants. The lipid fractions of agria and organpipe are chemically similar and contain high concentrations of several 3β,6α-dihydroxysterols. Larval viability tests using chemical constitutents of organpipe cactus demonstrate that the sterol diols are toxic toD. nigrospiracula but not to the resident, species,D. mojavensis. Agria and organpipe are therefore unsuitable as host plants forD. nigrospiracula. These results suggest that phytosterols play a major role in determining host plant utilization by cactophilicDrosophila in the Sonoran Desert.

Triterpenes in organ pipe cactus

Abstract Twelve triterpenes in the lup-20(29)-ene and olean-12-ene series have been isolated from the triterpene glycoside and lipid fractions of organ pipe cactus. Physical properties and chromatographic mobilities of these compounds and some of their derivatives are given and they are arranged in a biosynthetic scheme based on degree of oxidation. Betulinic and oleanolic aldehydes, two of the cactus triterpenes, were also synthesized and fully characterized.

Sterculic derivatives and pink egg formation.

Sterculyl alcohol has been methylated and reduced to form the methoxyl and hydrocarbon derivatives. These two derivatives, sterculyl alcohol and the polymers of sterculic acid and methyl sterculate were fed to laying hens. The sterculic derivatives caused pink egg formation but the polymers did not.

Metabolism of lathosterol byDrosophila pachea

Drosophila pachea is a Sonoran Desert cactiphilic species unable to utilize cholesterol or cholestanol for larval growth and maturation. Lathosterol (7-cholesten-3β-ol) was added to a sterol deficient medium on which an axenic culture ofD. pachea was maintained. 7-Dehydrocholesterol was identified as the sterol metabolite in adult flies by gas liquid and thin layer chromatography and by its UV spectrum.

The addition of mercaptans to methyl sterculate and sterculene: An hypothesis concerning the nature of the biological activity exhibited by cyclopropene derivatives

Lipids that contain a cyclopropene ring have been found to be biologically active when incorporated into the diet of laying hens. Methyl sterculate and sterculene (1,2-di-n-octylcyclopropene) are examples of these compounds. When added to dilute solutions of methyl mercaptan and β-mercaptopropionic acid, the sulfhydryl group added to the double bond of the cyclopropene ring. The cyclopropyl methyl and 2-carboxyethyl derivatives were isolated and their structure established. This reaction of sulfhydryl groups with the cyclopropene ring may have its counterpart in the animal’s body, and could be the cause of the physiological effects that are observed when cyclopropene derivatives are fed to laying hens.

SENITA CACTUS: A PLANT WITH INTERRUPTED STEROL BIOSYNTHETIC PATHWAYS

Abstract Locereol (4α-methylcholesta-8,14-dien-3β-ol) and 5α-cholesta-8,14-dien-3β-ol, not previously isolated from plants, 24-methylenelophenol, lathosterol, 5α-campest -7-en-3β-ol and spinasterol are present in senita cactusin addition to the lophenol and schottenol described previously.

The distribution of sterols, alkaloids and fatty acids in senita cactus, Lophocereus schottii, over its range in Sonora, Mexico

Abstract Young and old stems of senita cactus have been examined for their sterol, alkaloid and fatty acid content. No systematic cline was observed when these phytochemical characteristics were compared with the location in Sonora where the plants were gathered. Instead, there were significant differences between young and mature stems of a single plant and between the epidermis and cortex of a single stem. These differences did not correlate with plant morphology or with a chromosomal inversion in Drosophila pachea , an insect that uses senita as its sole breeding site.

The reactions of 1,2-dioctylcyclopropene with silver nitrate

Sterculene (1,2-di-n-octylcyclopropene) reacts slowly with dilute solutions of silver nitrate in acetonitrile with formation of a silver mirror and production of 9-methylene-10-octadecanone. The reaction is rapid in alcohols; finely-divided silver is formed and sterculene is transformed into 9-alkoxymethyl-9-octadecenes together with smaller amounts of the unsaturated ketone. In neither case is the silver formed in stoichiometric quantities. The reaction ofSterculia foetida oil methyl esters with alcoholic silver nitrate was used to demonstrate the possible application of this reaction to the determination of cyclopropene fatty acids.