Pheromones fractionation

Fig. 20.3 Preparation of pheromone extract for behavioural trials. Secreted proteins from D. ocoee pheromone were size fractionated on Sephadex-G75 gel filtration resin prior to behavioural testing. AU (absorption units) = wavelength = 220 nm). Inset SDS-PAGE (15% Tris-Tricine) lanes are A. Standards, B. Whole extract, C-G. pooled and concentrated fractions 12-16, 17-20, 21-24, 25-28 and 25-39 respectively. The experimental pheromone fraction was D ( 17—20)...

Twenty male-female pairs each mated on two different trial nights, once with a pheromone treatment (the 20-25 kDa fraction of the male courtship pheromone) and once with a saline treatment (n = 20 paired values). The duration of courtship was reduced significantly when pairs were treated with the pheromone fraction vs the saline control (t = 1.73, df= 19, P < 0.02). For these 20 pairs, the average courtship duration was 54 min when treated with the pheromone fraction, and 70 min when treated with the saline control. Thus, the control treatment resulted in courtships that were approximately 30% longer. 

Multiple lines of evidence suggest that SPF, a single protein within the 20-25 kDa pheromone fraction, is responsible for female behavioural response. First, this major protein component within the D. ocoee fraction was genetically very similar to the precursor of sodefrin (Palmer, Watts, Houck, Picard and Arnold 2007), and sodefrin is a known reproductive pheromone in newts (Kikuyama, Toyoda, Ohmiya, Matsuda, Tanaka and Hayashi 1995 Kikuyama and Toyoda 1999). Second, a separate study showed that the cDNA library of proteins expressed in male D. ocoee mental glands contained a high proportion (25%) of... 

In rabbits, the as yet unidentified maternal signal during lactation has analogous properties in guiding the reliable orientation of suckling, mainly via MOS input (Hudson and Distel, 1986 Schaal et al., unpubl.). Minor fractions may still function as flag contributors, exemplified by the attractiveness of proestrous elephant urine. Male responses show that intact urine is conspicuously more attractive in comparison with the pure insect mammal pheromone (9.) presented in water (Rasmussen et al., 1996). 

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... 

In the plethodontid salamander D. ocoee, courtship duration was reduced for male-female pairs in which the female received a protein signal from the 20-25 kDa fraction of the male courtship pheromone. We interpret this reduction in courtship duration as an increase in receptivity for females receiving the pheromone. 

Chemicals that cycle in abundance are obvious candidates for consideration as pheromones. Armed with effective analytical techniques we can address the issue of cane toad chemical plasticity with respect to different variables (Table 39.1). We will also investigate the impact of crude and fractionated secretions on the behavior of cane toads, and compare these responses between the same groupings of animals, i.e. sex, life-stage, season etc. We have identified three stages in the cane toad life cycle that are likely controlled by chemical signals, and are an ideal place to start attempting to disrupt their chemical ecology. 

All of the long-range kairomones attractive to parasitoids that have been identified thus far are sex pheromones of the hosts. However, we are probably aware of only a small fraction of the predators and parasites that are eavesdropping on the pheromonal communications of their prey or hosts. While the evolution of individuals that are as inconspicuous as possible to their enemies is favored, it is impossible for a species to completely avoid emitting chemical signals. Thus, pheromones that are important to reproduction or other vital functions, and are good indicators of the presence of a species, are available for predators or parasitoids to exploit. 

The EAG technique as a bioassay tool for active fractions has been used in the identification of sex pheromones of many insect species in several orders and remains as a key factor in the identification of pheromones. In the recent identification of the brownbanded cockroach pheromone supellapyrone (7) (Figure 2), the EAG technique was used throughout the entire process of isolating and purifying active material from 12,000... 

Food odors are also important as attractants for traps both on their own or in combination with pheromone lures as synergists or additive attractants. Food odors can be used to improve the capture of species that do not have commercially available pheromone lures, of females that do not respond to traps with sex pheromones, and of immature stages. In a number of situations, pheromones combined with food odor are more attractive then either alone (Landolt and Phillips, 1997 Phillips et al., 1993 Trematerra and Girgenti, 1989). Food odor has an advantage over food bait packs because typically the insect is unable to develop on the chemical fraction containing the attractant in contrast to food bait packs. The effectiveness of food attractants can be diminished in environments that contain other food odors. 

Chlorochroa sayi males produce a pheromone consisting primarily of methyl geranate, with trace amounts of methyl citronellate and methyl dihydrofarnesoate [107]. Methyl geranate is readily available in multigram quantities from fractional distillation of the commercially available mixture of methyl geranate and methyl nerate (J.G. Millar, unpublished data), or the two isomers can be separated chromatographically [107]. 

Candidate compounds for sex pheromones have been isolated from cervico-vaginal mucus of domestic cows. Several diols, ketones, and amines were identified in fractions that released sexual responses in bulls, such as sniffing and licking the sample, fiehmen, penile contraction, and preputial secretion (Klemm etal, 1987). 

Eine, J. M. and Sorensen, P. W. (2004). Bioassay-guided fractionation demonstrates that the sea lamprey migratory pheromone is a mixture of at least three sulfated steroids. lnAnnualMeetingoflnternationalSocietyofChemicalEcology,July 2004, Ottawa, Canada. 

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. 

Kitamura and Takahashi (1973) described the mating behavior of P. japonica and provided behavioral evidence for a sex pheromone. A purified active fraction from... 

A non-volatile contact pheromone contained in the cuticular wax of females elicits a wing-raising courtship response from males (Roth and Wilhs, 1952 Ishii, 1972). Nishida and co-workers obtained three active chromatographic fractions from hexane extracts of 224000 females. The major active component was identified as... 

Analytical studies of the tergal secretions of male B. germanica have identified a number of volatile compounds, none of which has so far been subjected to behavioral assays on females. Brossut et al. (1975) found p-hydroxybenzyl alcohol, o-hydroxybenzyl alcohol, di- and tri-methylnaphthalene, benzothiazole, two isomers of nonyl phenol, and myristic, palmitic, and oleic acids. The fatty acids constituted > 92% of the volatile fraction given their abundance in feces and frass, and their role as putative aggregation pheromones (Wileyto and Boush, 1983 Fuchs et al., 1985 Wendler and Vlatten, 1993 Scherkenbeck et al., 1999),... 

R=OH). With less polar chloride substituents, however, the RhuA dia-stereoselectivity is reduced and a considerable fraction of the FucA configurated product (40%) is also formed. Interestingly, alkaline cyclization in the latter occurs with an inverse preference to furnish 177, which contains the enantiomeric bicyclic [3.2.1] structure shared by the FruA product 175 as well as by (S)-( — )-frontalin 178, the aggregation pheromone of the southern pine beetle Dendroctonus frontalis. 

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