Pheromones signaler

The chemoreceptive mechanisms in amphibia are undoubtedly worthy of further analysis, not only for their own sake, but to provide clues as to the origination of advanced chemosignal systems. As noted above, a pheromonal signal from the mental gland acts as a courtship/ receptivity inducer. The plethodontid receptivity factor (PRF) (Chap. 3) despite its size (22 kD), seems to have been converted from its internal role as an inter-cellular cytokine, to an inter-individual coordinator of reproductive activity (Rollmann et al., 1999). Endocrine or... 

Berghard A. and Buck L.B. (1996). Sensory transduction in vomeronasal neurons evidence for G-alpha-o, G-alpha-i2, and adenylyl cyclase II as major components of a pheromone signaling cascade. J Neurosci 16, 909-918. 

Dulac C. (2000). Sensory coding of pheromone signals in mammals. Curr Opin Neurobiol 10, 511-518. 

Rasmussen, L.E.L. and Schulte, B.A. (1999) Ecological and biochemical constraints on pheromonal signaling systems in Asian elephants and their evolutionary implications. In R. Johnston, D. Miiller-Schwarze and P. Sorenson (Eds.), Advances in Chemical Communication in Vertebrates, Vol. 8 Kluwer Academic/Plenum Press, New York, pp. 46-62. 

The demonstration of this behavioural response to a male pheromone signal is significant because of the manner in which the pheromone was delivered. Most other vertebrate examples of reproductive pheromones involve reception via the olfactory system(s). In contrast, D. ocoee females received the pheromone via diffusion through the dorsal skin. We assume that the well developed superficial capillary system of these lungless salamanders is the route by which the male pheromone was transported to whatever target tissue(s) initiated responses that affected female reproductive behaviour. 

The delivery of male courtship pheromones is widespread among plethodontid salamanders (Houck and Arnold 2003), and other courtship pheromones are being discovered for this group (Houck, Palmer, Watts, Arnold, Feldhoff and Feldhoff 2007). The mode by which these pheromones are transferred to the female apparently has been modified from delivery via diffusion into the circulatory system to delivery that directly stimulates vomeronasal receptors (Fig. 20.1 Houck and Sever 1994 Watts et al. 2004 Palmer et al. 2005 Palmer et al. 2007). The behavior patterns and morphologies associated with these two delivery modes often remain static for millions of years. In contrast, evolution at the level of pheromone signals is apparently an incessant process that continuously alters the protein sequence and composition of pheromones both within and among species (Watts et al. 2004 Palmer et al. 2005 Palmer et al. 2007). 

Luo, M., Fee, M.S. and Katz, L.C. (2003) Encoding pheromonal signals in the accessory olfactory bulb of behaving mice. Science 299, 1196-201. 

Watts, R.A., Palmer, C.A., Feldhoff, R.C., Feldhoff, P.W., Houck, L.D., Jones, A.G., Pfren-der, M.E., Rollmann, S.M. and Arnold, S.J. (2004) Stabilizing selection on behavior and morphology masks positive selection on the signal in a salamander pheromone signaling complex. Mol. Biol. Evol. 21, 1032-41. 

Coureaud, G. (2001) Olfactory regulation of sucking in newborn rabbit Ethological and chemical characterization of a pheromonal signal. PhD Thesis, University of Paris. 

Our neurophysiological studies have focused on three important properties of the sex-pheromonal signal its quality (chemical composition of the blend), quantity (concentrations of components), and intermit-tency [owing to the fact that the pheromone in the plume downwind from the source exists in filaments and blobs of odor-bearing air interspersed with clean air (47, 48)]. Each of these properties of the pheromonal message is important, as the male moth gives his characteristic behavioral responses only when the necessary and sufficient pheromone components A and B are present in the blend (44), when the concentrations and blend proportions of the components fall within acceptable ranges (49), and when the pheromone blend stimulates his antennae intermittently (39, 50). In our studies, we examine how each of these important aspects of the odor stimulus affects the activity of neurons at various levels in the olfactory pathway. 

The male moth s pheromone-analyzing olfactory subsystem is composed of pheromone-specific antennal ORCs projecting to the similarly specialized, anatomically defined MGC in the AL and MGC output neurons that project to olfactory foci in the protocerebrum. This subsystem is an example of a labeled-line pathway (18). Its specialization to detect, amplify, and analyze features of sex-pheromonal signals and its consequent exaggeration of common olfactory organizational principles... 

Conjugsil plasmid Pheromone signal sequence Designation of the active pheromone Size of precursor (aa) Reference(s)... 

It is not always clear how pheromone signals are detected in mammals. Most vertebrates, mice for example, have a VNO in addition to the main olfactory system. The VNO has two separate families of olfactory receptors Vlr, 137 functional receptors in mice V2r, 60 functional receptors in mice. The genes for these are only distantly related to those for the main olfactory receptors, suggesting that these systems evolved independently. As a general rule, it is the VNO and not the olfactory epithelium that is responsible for detecting pheromone molecules. However, it has been demonstrated that mice whose VNO has been surgically removed can discriminate MHC-determined odor types. This finding clearly implicates the main olfactory system in the detection of pheromones. 

Pheromone (sex attractant). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Pheromone (signaling). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Phospholipidemic effect. Oil, administered to phospholipids transfer protein knockout (PLTPO)-deficient mice, produced an increase of phospholipids and free cholesterol in the VLDL-LDL region of PLTPO mice. Accumulation of phospholipids and free cholesterol was dramatically increased in PLTPO/HLO mice compared to PLTPO mice. Turnover studies indicated that coconut oil was associated with delayed catabolism of phospholipids and phospho-lipids/free cholesterol-rich particles. Incubation of these particles with hepatocytes of coconut-fed mice produced a reduced removal of phospholipids and free cholesterol by SRBI, even though SRBI protein expression levels were unchanged . 

Moore, A. J., Reagan, N. L. and Haynes, K. F. (1995). Conditional signaling strategies effects of ontogeny, social experience and social status on the pheromonal signal of male cockroaches. Animal Behaviour 50 , 191-202. 

Gemeno, C., Moore, A.J., Preziosi, R. F. and Haynes, K.F. (2001). Quantitative genetics of signal evolution a comparison of the pheromonal signal in two populations of the cabbage looper, Trichoplusia ni. Behavior Genetics 31 157-165. 

Morishita, M. Morimoto, E Kitamura, K. Koga, T Fukui, Y. Maekawa, H. Yamashita, I. Shimoda, C. Phosphatidylinositol 3-phosphate 5-kinase is required for the cellular response to nutritional starvation and mating pheromone signals in Schizosaccharomyces pombe. Genes Cells, 7, 199-215 (2002)... 

Inouye, C., Dhillon, N. and Thorner, J. (1 997) Ste5 RING-H2 domain role in Ste4-promoted oligomerization for yeast pheromone signalling. Science 278, 103-106. 

Chen, C., Zheng, B., Han, J., and Lin, S. C. (1997). Characterization of a novel mammalian RGS protein that binds to Ga proteins and inhibits pheromone signaling in yeast. / Biol. Chem. 272, 8679-8685. 

Our understanding of pheromone reception had undergone dramatic change just prior to 1987 with the proposal that Pheromone Binding Proteins (PBPs) and pheromone degrading enzymes transported and inactivated pheromonal signals... 

Of the eight orders in this group, no sex pheromones are known in the Grylloblattaria and Embiidina. Of the remaining orders, probably the best studied are the cockroaches and termites, particularly the latter because of the involvement of pheromonal signals in their social structure (Vander Meer el al., 1998). 

Aphids exhibit vivipary and ovipary, depending on environmental conditions. Oviparous aphids are sex pheromone competent, and females attract males with sex pheromonal signals in contrast, viviparous females are unable to produce pheromone (Crema and Bergamini, 1985). The pheromone is produced in tibial plaques, which are absent in viviparous females. The occurrence of vivipary and loss of tibial plaques is triggered by juvenile hormone, under conditions that stimulate vivipary. 

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