Insects, hormones pheromones

The use of microwaves for synthesis of olefins via elimination has become increasingly interesting in recent years because olefins are the basic moiety of many ole-finic natural products, for example, the insect hormones, pheromone, etc. It is also used in nonenzymic biogenetic-like cyclizations to form polycyclic compounds. 

Morgan ED (1990) Insect trail pheromones a perspective in progress. In McCaffery AR, Wilson ID (eds) Chromatography and isolation of insect hormones and pheromones. Plenum, New York, p 259... 

Menon M. (1970). Hormone-pheromone relationships in the beetle, Tenebrio molitor. J. Insect Physiol. 16, 1123-1139. 

Structures of DSK I and II were determined by molecular biological techniques. Expression of these peptides has not been demonstrated, t Schoofs, L., in Chromatography and Isolation of Insect Hormones and Pheromones, in press. 

In addition to the L. maderae myotropic peptides, a series of five myotropic peptides were isolated and structurally characterized from head extracts of the cricket, Acheta domesticus. with the same purification system and bioassay (Holman, G. M., et al. Chromatography and Isolation of Insect Hormones and Pheromones, in press.). The structures of these five myotropic peptides, the achetakinins, are shown in Table 1. Like the leucokinins, the achetakinins (Ak s) contain a C-terminal pentapeptide core which is responsible for the myotropic activity (12). In Ak s III and V, the C-terminal pentamer is the same as the leucokinin pentamer (Phe-X-Ser-Trp-Gly-NH2, where X = Asn, His, Ser, or Tyr) but in Ak s I, II, and IV a slightly different pentamer (Phe-X-Pro-Trp-Glv-NH is present. 

The final peptide structure shown in Table 2 represents an insect sulfakinin recently isolated from br-cc/ca extracts of the locust, Locusta migratoria. and structurally characterized. A modification of the four-step HPLC purification system (10) in which all gradients were extended to a higher final acetonitrile concentration was utilized. In addition, a C-8 reverse-phase column was substituted for the C-18 column (Schoofs, L., et al. Chromatography and Isolation of Insect Hormones and Pheromones, in press.). The isolated hindgut of L. maderae was used as the bioassay. Lom-SK contains residues of Leu and Ala at the 2- and 3-positions, respectively. The remainder of the sequence is identical with the 2-10 sequence of LSK-II. 

L - leucokinin A - achetakinin. Average of five replicates. Threshold concentration determination procedure has been previously described (16). Holman, M., Nachman, R., and Wright, M. in Chromatogr. 6e Isolation of Insect Hormones and Pheromones. in press. 

E. D. Morgan I. D. Wilson, Insect Hormones and Insect Chemical Ecology. In Comprehensive Natural Products Chemistry, Vol. 8 Miscellaneous Natural Products including Marine Natural Products, Pheromones, Plant Hormones, and Aspect of Ecology,... 

Chemical Synthesis of Hormones, Pheromones and Other Bioregulators Table 7.2 Examples of incorrect and correct structures proposed for some insect pheromones Pheromone producers Proposed structures Correct structures... 

The most important ways of direct pheromone application are their combination with traps, and their joint application with insecticides, male sterilants or insect hormones on restricted parts of the area to be protected. This method of application permits a considerable reduction in the quantity of insecticide to be used which, besides its economical advantage, is important also from the aspect of environmental protection. 

Pheromones and analogues of insect hormones (both agonistic and antagonistic) continue to be investigated without, so far, producing substances of wide-ranging usefulness (see Section 4.7). 

Environmental and physiological factors controlling the production and/or emission of insect sex pheromones were reviewed by Shorey (5). Light intensity, temperature, host habitat, and air velocity are the main environmental variables. Physiological factors involved are time of day, age, previous experience, population density, diet, hormones and seasonal rhythms. 

Our knowledge of the endocrinology of insects first arose from studies on the metamorphosis of insects, and among the insect hormones the metamorphosis hormones have been the most thoroughly studiedi-. Considerably less is known about the myotropic and neurosecretory substances it is often not chear what physiological process is actually controlled. For further information about these substances other reviews must be consulted On the other hand, another group of active substances will be mentioned here, namely, the pheromones. They were defined as substances which are excreted to the outside by an individual of the same species, in which they release a specific reaction, for example, a definite behaviour or a developmental process. The principle holds that minute amounts are effective. The term "pheromone should be substituted for the somewhat ill-defined term ectohormones . 

Eisner, T. Meinwald, J. The Chemistry of Sexual Selection Proc. Nat. Acad. Sci. (USA) 1995, 92, 50-55. Karlson, P. The Chemistry of Insect Hormones and Insect Pheromones Pure Appl. Chem. 1967, 14, 75-87. Karlson, P. Chemie nnd Biochemie Der Insektenhormone Anpiew. Chem. 1963, 75, 257-265. 

Zurfluh, R., L. L. Dunham, V. L. Spain, and J. B. Siddall Synthetic studies on insect hormones. IX. Stereoselective total synthesis of a racemic boll weevil pheromone. J. Amer. Chem. Soc. 92,425- 27 (1970). 

Epoxides are not only key intermediates in several biosyntiieses they are also present in a number of secondary metabolites (Fig. 5). Again, the high reactivity of the epoxy moiety contributes to the bioactivity of these metabolites. This reactivity ensures short half-lives of metabolites, e.g., in juvenile hormones, pheromones, or the toxicity of some antibiotics. The methyl ester of 10,11-epoxyfamesenate 18 is a juvenile hormone synthesized by many insects. The pheromone disparlure 19 (see also Chapter 3 in this book) formed by the gypsy moth Lymantria dispar is active in only one enantiomeric form [8],... 

Behavioral and Hormonal Chemicals. Sex pheromones, which attract pests to traps, are used effectively to control some insect pests, like the grape berry moth (46) and cabbage looper. With other Insect pests, sex pheromones have been effectively used to monitor the size of pest insect populations to determine when pesticide treatments should be made. 

Abstract Pheromones are utilized by many insects in a complex chemical communication system. This review will look at the biosynthesis of sex and aggregation pheromones in the model insects, moths, flies, cockroaches, and beetles. The biosynthetic pathways involve altered pathways of normal metabolism of fatty acids and isoprenoids. Endocrine regulation of the biosynthetic pathways will also be reviewed for the model insects. A neuropeptide named pheromone biosynthesis activating neuropeptide regulates sex pheromone biosynthesis in moths. Juvenile hormone regulates pheromone production in the beetles and cockroaches, while 20-hydroxyecdysone regulates pheromone production in the flies. 

---