Antennal Enriched Odorant Binding Proteins Are Required for Odor Communication in Glossina f. fuscipes

Olfaction is orchestrated at different stages and involves various proteins at each step. For example, odorant-binding proteins (OBPs) are soluble proteins found in sensillum lymph that might encounter odorants before reaching the odorant receptors. In tsetse flies, the function of OBPs in olfaction is less understood. Here, we investigated the role of OBPs in Glossina fuscipes fuscipes olfaction, the main vector of sleeping sickness, using multidisciplinary approaches. Our tissue expression study demonstrated that GffLush was conserved in legs and antenna in both sexes, whereas GffObp44 and GffObp69 were expressed in the legs but absent in the antenna. GffObp99 was absent in the female antenna but expressed in the male antenna. Short odorant exposure induced a fast alteration in the transcription of OBP genes. Furthermore, we successfully silenced a specific OBP expressed in the antenna via dsRNAi feeding to decipher its function. We found that silencing OBPs that interact with 1-octen-3-ol significantly abolished flies’ attraction to 1-octen-3-ol, a known attractant for tsetse fly. However, OBPs that demonstrated a weak interaction with 1-octen-3-ol did not affect the behavioral response, even though it was successfully silenced. Thus, OBPs’ selective interaction with ligands, their expression in the antenna and their significant impact on behavior when silenced demonstrated their direct involvement in olfaction.

Classification of Mixed Odors Using A Layered Neural Network

Odor classification has been forcused due to one of five senses of human being. If we could establish the odor classification technology, we would expect various new technology since human being requires five sences to acheive higher quality information processing and sophistcated decision making. For example, we could expect the odor classification and odor synthesis, which enable us to achieve odor communication technology. Furthermore, the odor classification would be applicable to keep the society safe by detecting the dangerous odors and to make our life more satisfactory by using additional odor information. In this paper we develop an electronic nose using a neural network. The neural network is a multi-layered neural network based on the gradient method. After classifying the various odors, we consider the classification in case that mixed odors are measured. To improve the classification accuracy we adopt a genetic algorithm to find a reduction factor to separate two mixed odors.

Reproductive status influences odor preferences of the meadow vole, Microtus pennsylvanicus, in winter day lengths

Sporadic winter breeding is a common occurrence in populations of arvicoline rodents. To elaborate the olfactory basis of winter breeding, odor preferences of meadow voles that did or did not develop their reproductive systems in short day lengths were compared. Voles that did not respond to short days with reproductive inhibition were reproductively mature and are termed nonresponders, while voles that did respond to short days with reproductive inhibition were reproductively immature and are termed responders. Nonresponder females preferred odors of nonresponder males over those of nonresponder females and nonresponder female over responder female odors. Nonresponder males preferred nonresponder over responder female odors. The mutual attraction between male – female and female – female nonresponders may facilitate winter breeding and female – female dyad formation for communal rearing of young, respectively. Responder females preferred odors of female responders over those of male responders and responder over nonresponder male odors. Olfactory preferences of nonresponder short-day voles were not equivalent to those of reproductively competent long-day animals. Differences in odor communication between responder and nonresponder voles are attributable only in part to differences in gonadal hormone secretion.