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81.
S.?JarauEmail author M.?Hrncir R.?Zucchi F.?G.?Barth 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2004,190(3):233-239
The pheromones used by several species of stingless bees for scent trail communication are generally assumed to be produced by the mandibular glands. Here we present strong evidence that in Trigona recursa these pheromones originate from the labial glands, which are well developed in the heads of foragers. Analysis of the behavior involved in scent marking shows that a bee extends her proboscis and rubs it over the substrate. A single scent marking event lasts for 0.59±0.21 s while the bee runs a stretch of 1.04±0.37 cm on a leaf. According to choice experiments the bees are attracted by a feeder baited with labial gland extract (84.2±6% of the bees choose this feeder) but repelled from a feeder baited with mandibular gland extract (only 27.5±13.1% of the bees choose this feeder). They do not discriminate between two clean feeders (49.6±3% of the bees at a feeder). 87±5.1% of bees already feeding leave the feeder after the application of mandibular gland extract whereas only 6.2±4.9% and 2.6±4% do so when labial gland extract or pure solvent was applied. 相似文献
82.
The chemical composition of the vomeronasal organ (VNO) was investigated by means of in vitro proton magnetic resonance spectroscopy (MRS) in prepubertal and adult mice of both sexes. Results demonstrate that MRS detects several chemical constituents in the VNO, showing their age- and sex-associated changes in concentration. Preliminary experiments also suggest the ability of MRS to show compositional changes in the VNO after pheromonal stimulation. MRS can serve as a useful technique to investigate vomeronasal chemoreception. 相似文献
83.
Wirenia argentea and Genitoconia rosea feed on Cnidaria like most representatives of the molluscan taxon Solenogastres (Aplacophora, Neomeniomorpha sensu Scheltema). The structure and histochemistry of the foregut are described based on histologic, semithin, and ultrathin section series. The ultrastructure was analyzed by means of transmission electron microscopy. There are two sets of unicellular glands: a narrow row of preoral gland cells opening to the preoral area, and pharyngeal gland cells in high numbers. Preoral gland cells produce serous secretions in W. argentea, but mucosubstances in G. rosea, whereas pharyngeal gland cells are similar in structure and histochemistry in both species. Based on the size and electron density of gland vesicles, five distinct types of pharyngeal gland cells can be defined. In contrast to earlier assumptions, all types of pharyngeal gland cells produce serous secretions, most probably representing digestive ferments, but no mucosubstances. 相似文献
84.
85.
The sex pheromone glands of Lutzomyia cruzi male sand flies (Diptera: Psychodidae) were analyzed by cytochemical techniques. In adult males, the epithelium at the fourth abdominal tergite is modified into a glandular epithelium, with large columnar gland cells located side by side. The gland cell cytoplasm contains a large number of mitochondria and peroxisomes, the latter with positive (electron-dense) reaction for catalase, a typical peroxisomal enzyme marker. The gland cell cytoplasm also contains a central vacuolated area, with a large number of electron-lucent vacuoles, not limited by a unit membrane. In well-preserved preparations such vacuoles present a homogenous and slightly electron-dense content, typical of lipid droplets. Indeed, incubation of the tergites with imidazole-buffered osmium tetroxide (to detect lipids) resulted in positive reaction in these vacuoles, as well as in between the microvilli of the gland cells. Use of the osmium–potassium iodide (Os–KI) technique allowed to demonstrate the presence of several endoplasmic reticulum (ER) profiles, as expected in secretory cells. Our data suggest that ER, lipid droplets and peroxisomes are involved in the sand fly pheromone biosynthesis. 相似文献
86.
The turbellarian Urastoma cyprinae (Graff) occurs on the gills of various bivalve species including the mussel Mytilus galloprovinciallis, where it is known to cause serious damage. More recently, it has been shown that the worms are strongly attracted to the gill of the American oyster (Crassostrea virginica) and are capable of inducing changes to the composition of proteolytic enzymes of the host mucus. Such changes may be attributable to secretory products released by the worms. Mucous glands (11-18 mum in diameter) produce minute spherules (0.7-0.9 mum in diameter) tightly bound together. The glands occupy approximately 20% of the body volume and are the most voluminous secretory organs in the worm. The smaller rhabdoid glands are unevenly distributed throughout the peripheral parenchyma and contain secretory granules of 0.35-1.2 mum in diameter. The latter occur most prominently along the distal margins of the epidermis. The frontal pole of U. cyprinae consists of a complex assembly of mucous and rhabdoid gland cells as well as other glandular structures. Collectively, these bodies release their contents to the outside via narrow gland necks. The overall organization is consistent with the frontal gland previously described for other free-living turbellarians, including other rhabdocoels. A variety of secretory products, displaying variations in staining properties, have likewise been identified in association with the body wall from other regions of the worm. This work attempts to gain a better appreciation of the secretory structures associated with the worm tegument, focusing primarily on the widespread mucous and rhabdoid glands. The secretions play a role in host-parasite interactions. 相似文献
87.
Simmons LW 《Journal of evolutionary biology》2003,16(4):624-634
The sexy-sperm hypothesis predicts that females obtain indirect benefits for their offspring via polyandy, in the form of increased fertilization success for their sons. I use a quantitative genetic approach to test the sexy-sperm hypothesis using the field cricket Teleogryllus oceanicus. Previous studies of this species have shown considerable phenotypic variation in fertilization success when two or more males compete. There were high broad-sense heritabilities for both paternity and polyandry. Patterns of genotypic variance were consistent with X-linked inheritance and/or maternal effects on these traits. The genetic architecture therefore precludes the evolution of polyandry via a sexy-sperm process. Thus the positive genetic correlation between paternity in sons and polyandry in daughters predicted by the sexy-sperm hypothesis was absent. There was significant heritable variation in the investment by females in ovaries and by males in the accessory gland. Surprisingly there was a very strong genetic correlation between these two traits. The significance of this genetic correlation for the coevolution of male seminal products and polyandry is discussed. 相似文献
88.
转基因小鼠乳腺表达人瘦蛋白的研究 总被引:8,自引:0,他引:8
利用转基因动物乳腺生产药用蛋白质是近年来研究的热点,在这方面已有不少成功的例子,展现出良好的应用前景[1,2].本研究选择人瘦蛋白基因作为目标基因是因为其表达产物瘦蛋白能对人体内脂肪的蓄积和能量消耗进行有效的反馈调控,美国科学家已将用E.coli表达的人瘦蛋白用于人肥胖症的治疗并取得了良好的治疗效果[3],但尚未见到利用转基因动物乳腺表达这种蛋白质的研究报道. 相似文献
89.
Patterns of divergence in the effects of mating on female reproductive performance in flour beetles 总被引:3,自引:0,他引:3
Nilsson T Fricke C Arnqvist G 《Evolution; international journal of organic evolution》2002,56(1):111-120
Sexual selection can lead to rapid divergence in reproductive characters. Recent studies have indicated that postmating events, such as sperm precedence, may play a key role in speciation. Here, we stress that other components of postmating sexual selection may be involved in the evolution of reproductive isolation. One of these is the reproductive investment made by females after mating (i.e., differential allocation). We performed an experiment designed to assess genetic divergence in the effects of mating on female reproductive performance in flour beetles, Tribolium castaneum. Females were mated to males of three different wild-type genotypes at two different frequencies, in all possible reciprocal combinations. Male genotype affected all aspects of female reproduction, through its effects on female longevity, total offspring production, reproductive rate, mating rate, and fertility. Moreover, male and female genotype interacted in their effects on offspring production and reproductive rate. We use the pattern of these interactions to discuss the evolutionary process of divergence and suggest that the pattern is most consistent with that expected if divergence was driven by sexually antagonistic coevolution. In particular, the fact that females exhibited a relatively weak response to males with which they were coevolved suggests that females have evolved resistance to male gonadotropic signals/stimuli. 相似文献
90.
To determine the cause of the unique yellow coloration in mandibular glands of soybean-fed Helicoverpa zea larvae, the accumulation of carotenoids in various tissues of last instar larvae fed soybean, cotton and tomato foliage was quantified. Five carotenoids were detected in the foliage of all host plants but at significantly different concentrations. Xanthophylls rather than carotenes were most likely to accumulate in larval tissues. Carotenoids accumulated at different rates and some were significantly affected by larval diet. Highest levels of carotenoid accumulation, notably lutein, were detected in the testes, followed by midgut epithelium, fat body and integument. The midgut epithelium contained the greatest and the testes the least diversity of carotenoid types. Low levels of lutein were detected in both labial and mandibular glands. Tomato foliage had the highest carotenoid content and caterpillar tissues fed these leaves often had the highest amounts of carotenoid. However, the accumulation of carotenoids did not protect larvae from antibiotic effects of tomato foliage because these caterpillars had the highest mortality and slowest growth rates of all the three host plants. Transport and absorption of lipid and oxidative stress may be some reasons for differential carotenoid accumulation. 相似文献