Pheromone activity

PLC of lipids is discussed in Chapter 12. Lipids play a vital role in virtually all aspects of human and animal life. Many smdies of food quality, human health, metabolic and ageing processes, pheromone activity in animals, etc., benefit greatly from the use of PLC for the separation and isolation of lipids. 

The production of a female-influencing secretion from the chin gland of male Plethodontid salamander (P. jordani) points to a similar extension of function by the acquisition of female olfactory sensitivity to an intercellular signal protein. Female receptivity is enhanced by a male cytokine-like compound of the interleukin-6 family, in its released form. Rollman et al. (1999) note that pheromonal activity is a previously unrecognised function for cytokines. 

Behavioural testing of protein fractions has not kept pace with semiochemical studies. Belcher et al. (1990) found that the mixed scent marks of the Saddle-backed Tamarin (S. fusicollis) comprise urine and genital/suprapubic gland secretions. Both sexes deposit mixtures of pheromonally active large molecules at, for example, exudate feeding... 

Robertson D., Benyon R.L. and Evershed R. (1993). Extraction, characterization and binding analysis of two pheromonally active ligands associated with major urinary proteins of house mouse (Mus musculus). J Chem Ecol 19, 1405-1416. 

There are three reviews emphasizing the importance of synthesis in pheromone science [4],in semiochemicals research [5],and in chemical ecology [6]. Stereochemistry-pheromone activity relationships are also discussed in the above three reviews, and more thoroughly in three other reviews [7-9]. 

Scheme 7 summarizes the synthesis of (7JR,llS)-7,ll-dimethylheptadecane (1), the female sex pheromone of the spring hemlock looper (Lambdina athasaria) by Mori [ 18]. Enantiopure alkanes are usually synthesized by coupling enantio-pure building blocks derived from natural products or compounds prepared by asymmetric synthesis. Even among hydrocarbons, chirality is very important for pheromone activity, and in this particular case meso-1 was bioactive, while neither (7R,11R)-1 nor (7S,11S)-1 showed bio activity. 

By synthesizing pure enantiomers of pheromones, various stereochemistry-pheromone activity relationships could be clarified. For example, in the case of sulcatol (6-methyl-5-hepten-2-ol),both the enantiomers are necessary for bioactivity. For other relationships, please refer to [4-9]. 

Fig. 4 Gas chromatographic traces of extracts from females of the pale brown chafer Phyl-lopertha diversa monitored by a conventional detector, flame-ionization detector (FID), and a biosensor, electroantennographic detector (EAD), using a male antenna as the sensing element. Although the peak of the sex pheromone (arrow) is hardly seen in the FID trace, its pheromonal activity was initially indicated by the strong EAD peak. Structural elucidation, followed by synthesis and behavioral studies lead to the identification of an unusual sex pheromone, l,3-dimethyl-2,4-(lff,3ff)-quinazolinedione [124]. It is unlikely that this minor compound would be fished out by a bioassay-oriented isolation procedure...

Finally, preputial secretion of male mice probably assumes pheromone activity as attractant for females only after having been metabolized by microorganisms (Ninomiya and Kimura, 1988). 

A pheromone is functionally defined as a conspecific compound(s) that affects a receiver. Sources such as urine or gland secretions typically contain many compounds of which only some are pheromonally active. So in most cases, a pheromone is more than a single compound and less than a secretion ( scent ), it is rather a group of active compounds in a secretion or excretion that supply information to, or change behavior in, another conspecific. 

Muller-Schwarze, D. and Houlihan, D. (1991). Pheromonal activity of single castoreum constituents in beaver. Castor canadensis. Journal of Chemical Ecology 17, 715-734. 

As expected for the SAMP-alkylation, the (4S)-configuration was generated in excess. Thus, the absolute stereochemistry of (—)-serricornin (148) could be determined to be (4S,6S,7S). Other synthetic stereoisomers of serricornin prepared by Mori et al. 165) were almost devoid of pheromone activity. 

The cases where terpene metabolism has been studied In Insects are very few Indeed. Certain Ips and Dendroctonus bark beetles convert monoterpenes such as a-plnene, 6-plnene and myr-cene to oxidation products, some of which have pheromonal activities ( 5, 3A, 35). A Dendroc tonus bark beetle s cytochrome... 

In early studies, the criterion for pheromonal activity was designated as the lowest concentration (ppm) of the candidate compound in a 10-fold dilution series that elicited a demonstrable response from test mites. Activity was expressed in terms of the dose of the test compound applied to the filter paper dispenser. More recently, more sophisticated bioassays using arenas have been developed, in which the movements of mites toward or away from test stimuli can be quantified (Nishimura et al., 2002). 

An alternative combination of an aggregation-alarm pheromone system is found in L. konoi. This species produces the aggregation pheromone lardolure (44) as a minor component, and the alarm pheromone neral (2) as a major component. If both pheromones are presented simultaneously, aggregation pheromone activity manifests only after the alarm pheromone has dissipated. Furthermore, it seems likely that the mites can regulate the production of each component independently, because the evidence suggests that each is produced at a different site. Therefore, lardolure may be produced essentially continuously, and its function as an attractant is temporarily overridden by the rapid release of the alarm pheromone under adverse circumstances. 

Kuwahara, Y. (1982). Pheromone study on acarid mites VII. Structural requisites in monoterpenoids for inducing the alarm pheromone activity against the mold mite, Tyrophagus putrescentiae (Schrank) (Acarina Acaridae). Applied Entomology and Zoology 17 127-132. 

Aggregation pheromone activity of the female sex pheromone, / -acaridial, in Caloglyphus polyphyllae (Acari Acaridae). Bioscience, Biotechnology and Biochemistry 65 1724-1728. 

To exclude the possibility of response toward tactile cues delivered from silk, silk has been extracted with various solvents and then retested in behavioral experiments (marked W in Table 4.1). This procedure implies pheromone usage but is not conclusive. The experimentum crucis, abehavioral test of the extract for pheromonal activity, often was not performed, particularly in older studies. A complicated issue is that solvent extraction of silk can alter its physical characteristics, as shown in... 

Fig. 4.1. Volatile ketones released by females of Agenelopsis aperta 2 weeks after their final molt. Compound 1 showed high pheromonal activity whereas 2 was inactive.

Females begin to emit pheromone 9 or more days after the adult molt (Bodenstein, 1970 Takahashi et al., 1976 Hawkins and Rust, 1977), but clearly, this is variable and temperature dependent. The attractancy of gut extracts made on the first day after the imaginal molt corresponds to that of 0.1 ng ( )-periplanone-B (Sass, 1983). During the next 20 days, the effectiveness of both fractions of the sex pheromone (periplanone-A and periplanone-B) in behavioral assays increases 100-fold and remains high for at least the next 45 days. Collection of airborne pheromone with Tenax followed by behavioral assays showed that periplanone-A and periplanone-B were released by 10-25-day-old females in equal amounts, equivalent to 0.6 ng periplanone-B per female per day (Sass, 1983). Yang et al. (1998) confirmed an increase in pheromone activity in the early adult but showed a decline in pheromone between days 20 and 30. 

Manabe, S. and Nishino, C. (1983). Sex pheromonal activity of (+)-bornyl acetate and related compounds to the American cockroach. Journal of Chemical Ecology 9 433 148. 

Nishii, Y Watanabe, K., Yoshida, T., Okayama, T Takahashi, S. and Tanabe, Y. (1997). Total synthesis of (—)-periplanones C and D. Their pheromonal activities against three Periplaneta species. Tetrahedron 53 7209-7218. 

Nishino, C., Takayanagi, H. and Manabe, S. (1982). Comparison of sex pheromonal activity on the American cockroach between acetates and propionates of verbenyl type alcohols. Agricultural and Biological Chemistry 46 2781-2785. 

Takahashi, S., Takegawa, H., Takabayashi, J., Abdullah, M., Fatimah, A. S. and Mohamed, M. (1988a). Sex pheromone activity of synthetic periplanone-B in male cockroaches of genera Periplaneta and Blatta. Journal of Pesticide Science 13 125-127. 

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