Hydrocarbon biosynthesis

Additional evidence came from the finding that sex pheromone production could be stimulated in male houseflies that do not normally produce detectable sex pheromone components. Male houseflies were found to have longer chain alkenes, Z9-27 H,but did not have Z9-23 H. Implantation of ovaries into male houseflies resulted in a change in hydrocarbon biosynthesis such that the longer chain alkenes were not made but rather they produced the shorter chain length Z9-23 H [240]. Likewise, injection of 20-hydroxyecdysone into males induced sex pheromone production in a dose-dependent manner. These studies demonstrated that males possess the biosynthetic capability to produce sex pheromone, but normally do not produce the 20-hydroxyecdysone necessary to induce sex pheromone production. Males became an excellent model in which to study the hormonal regulation of pheromone biosynthesis in the housefly. 

FIGURE 6 Speculative mechanism of Crl hydrocarbon biosynthesis from fatty acid hydroperoxides in algae. Homolytic cleavage of the hydroperoxide is assumed to give an allyl radical, which cyclizes to the thermolabile (1S,2R)-cyclopropane. The sequence is terminated by transfer of a hydrogen radical from C(16) to the -X-0 function. The cyclopropane rearranges to (6S)-ectocarpene as shown in Figure 4. 

Moths in the families Geometridae, Arctiidae, and some Noctuidae utilize hydrocarbons or epoxides of hydrocarbons as their sex pheromones. Hydrocarbon biosynthesis occurs in oenocyte cells that are associated with either epidermal cells or fat body cells (Wigglesworth, 1970). Once the hydrocarbons are biosynthesized, they are transported to the sex pheromone gland by lipophorin (Schal et al., 1998). The hydrocarbons can be released directly in the case of some moths or they are transformed into epoxides by addition of oxygen across one of the double bonds. 

Vaz A. H., Blomquist G. J., Wakayama E. J. and Reitz R. C. (1987) Characterization of the fatty acyl elongation reactions involved in hydrocarbon biosynthesis in the housefly Musca domestica. Insect Biochem. 18, 177-184. 

Mpuru S., Reed J. R., Reitz R. C. and Blomquist G. J. (1996) Mechanism of hydrocarbon biosynthesis from aldehyde in selected insect species requirement for O2 and N ADPH and carbonyl group released as C02. Insect Biochem. Molec. Biol. 2, 203-208. 

The sexual dimorphism of cuticular hydrocarbons is completed during the first three days after imaginal eclosion. During the same period, important physiological events take place, female oocyte maturation and vitellogenesis. A number of mutations have been described which affect ovarian development or endocrine control. These mutants were used to elucidate a possible hormone control mechanism used to regulate hydrocarbon biosynthesis. 

Guo L., Quilici D. R, Chase J. and Blomquist G. J. (1991) Gut tract microorganisms supply the precursors for methyl-branched hydrocarbon biosynthesis in the termite, Zootermopsis nevadensis. Insect Biochem. 21, 327-333. 

A 13C NMR study of methyl-branched hydrocarbon biosynthesis in the housefly. 

It is generally accepted that insects synthesize a majority of their cuticular hydrocarbons (Nelson and Blomquist, 1995), although studies have shown that dietary hydrocarbons are incorporated into cuticular lipids (Blomquist and Jackson, 1973a). However, for most species it appears that dietary lipid accounts for very small amounts of insect cuticular hydrocarbon. Some inquilines, which use cuticular hydrocarbons in chemical mimicry, synthesize hydrocarbons with a composition very similar to those of their host termites (Howard et al., 1980 see also Chapter 14). A number of studies with widely diverse insect species have established that the major site of hydrocarbon biosynthesis occurs in the cells... 

Reed, J.R., Hernandez, P., Blomquist, G.J., Feyereisen, R. and Reitz, R.C. (1996). Hydrocarbon biosynthesis in the housefly, Musca domestica substrate specificity and cofactor requirement of P450hyd. Insect Biochem. Mol. Biol., 26,... 

Figure 4.2 Pheromone hydrocarbon biosynthesis in Drosophila melanogaster (left) and Musca domestica (right). The steps within a grey background occur only in mature females.

Chertemps, T., Duportets, L., Labeur, C., Ueda, R Takahashi, K., Saigo, K. and Wicker-Thomas, C. (2007). A female-biased expressed elongase involved in long-chain hydrocarbon biosynthesis and courtship behavior in Drosophila melanogaster. Proc. Natl. Acad. Sci. USA., 104,4273-4278. 

Figure 5.3 Schematic drawing showing transport of hydrocarbons (and other lipids) from site of synthesis (oenocytes) to cuticle surface (epicuticle) and various tissues and glands. Arrows represent hypothetical transport of hydrocarbons (and/or precursors) [legends e epicuticule p procuticule h hydrocarbons (and/or precursors) d epidermal cell c canal issuing from an epidermal cell o oenocytes 1 lipophorins fm microsome fraction (reticulum endoplasmic of oenocytes, site of hydrocarbon biosynthesis) hi hemolymph pg pheromone glands ot other tissues (ovaries)] (updated from Bagnhres, 1996).

Arnold, M.T. and Regnier, F.E. (1975). Stimulation of hydrocarbon biosynthesis by ecdysterone in the flesh fly Sarcophaga bullata. J. Insect Physiol., 21,1581-1586. 

A female-specific desaturase gene responsible for diene hydrocarbon biosynthesis and courtship behaviour in Drosophila melanogaster. Insect Mol. Biol., 15,465 473. 

Legendre, A., Miao, X.-X., Da Lage, J.-L. and Wicker-Thomas, C. (2008). Evolution of a desaturase involved in female pheromonal cuticular hydrocarbon biosynthesis and courtship behavior in Drosophila. Insect Biochem. Mol. Biol., 38, 244-253. 

Elongation Reactions Involved in Hydrocarbon Biosynthesis in Insects... 

Studies with widely diverse insect species, including both the American cockroach and the housefly, have established that the major site of cuticular hydrocarbon biosynthesis is the cells associated with epidermal tissue or the peripheral fat body, particularly the oenocytes (J[). 

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