Ejaculatory bulb

Figure 4.6 (A) Biosynthesis of cis-vaccenyl acetate. (B) Expression of desatl in male reproductive tract. The same strain and same protocol were used as in Figure 4.4. High desatl expression was seen in the ejaculatory bulb. (C) Effect of desatl or elo68 overexpression in the ejaculatory bulb on cis-vaccenyl acetate production. The P(GawB)NP447 strain was crossed to a P-UAS /CyO strain. The progeny control desatl-GAL4/CyO was compared to desatl-GAL4/UAS. The values are means SEM of 10 individual measures (ng/fly).

An unsaturated ketone (Z)-14-tricosen-10-one, a prominent (6%) constituent of the cuticular lipid of the female housefly, M. domestica, is the major component of the sex pheromone mixture (Uebel et al., 1978). For several species of Drosophila, the cuticular lipids contain saturated and unsaturated ketones (C13-C17) which were characterized as components of aggregation pheromones. Identified structures included 2-tridecanone and 2-pentadecanone in D. hydei (Moats et al., 1987), (Z)-10-heptadecen-2-one in D. mul-leri (Bartelt et al, 1989), and 2-pentadecanone in D. busckii (Schaner et al., 1989). The ejaculatory bulb and surface lipids of three Drosophila species (D. martensis, D. buzzatii and D. serido) had the compound (Z)-10-heptadecen-2-one that functions as the major... 

Fig. (4). (A) MALDI mass spectra of the hemolymph from bacteria-challenged (BC-H) vs control (Ctrl-H) larvae of P, terranovae. The arrows indicate immune-induced components. (B) MALDI mass spectra of the whole fat body from bacteria-challenged (BC-FB) vs control (Ctrl-FB) larvae of P. terranovae. The arrows indicate immune-induced components while the arrowheads marked repressed molecules. Detection by MALDI-MS of (C) endogenous drosomycin in a fluorescent trachea from larvae (GFP-I-) vs a non-fluorescent portion (GFP-) of the same trachea, and (D) of endogenous pherokine-2 directly in a dissected ejaculatory bulb and leg expressing pherokine-2 G P.

Data which confirm the idea of the division of chromosomes into functionally autonomous zones have been obtained in experiments with in situ hybridization of poly tene chromosomes with labeled poly-(A)-containing RNA extracted from the ejaculatory bulbs of D. littoralis at various stages of differentiation. The label was obtained in the group of bands which are packed together, e.g., only the adjacent bands were labeled. The part of chromosomes which separated these clusters was without label (Karasik et al., 1978). 

As an example of one experiment, 0.2 xl of sodium [l- C]acetate containing 440,000 cpm (counts per minute) was incubated with the ejaculatory bulbs at pH 6.8 in phosphate buffer. The products were extracted with hexane and subjected to radio-gas chromatography. The total label recovered was 54,000 cpm, but most of this was in fatty acids, 1162 cpm were recovered in the heptadecenone peak (2.15% of recovered label, 0.26% of applied label) and 625 cpm in tridecanone (1.15% of recovered label, 0.14% of applied label). The experiments effectively proved the site of biosynthesis and showed the compounds were being synthesized from acetate units. 

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