Academic literature on the topic 'Or67d'

Background High-throughput sequencing generates large volumes of biological data that must be interpreted to make meaningful inference on the biological function. Problems arise due to the large number of characteristics p (dimensions) that describe each record [n] in the database. Feature selection using a subset of variables extracted from the large datasets is one of the approaches towards solving this problem. Methodology In this study we analyzed the transcriptome of Glossina morsitans morsitans (Tsetsefly) antennae after exposure to either a repellant (δ-nonalactone) or an attractant (ε-nonalactone). We identified 308 genes that were upregulated or downregulated due to exposure to a repellant (δ-nonalactone) or an attractant (ε-nonalactone) respectively. Weighted gene coexpression network analysis was used to cluster the genes into 12 modules and filter unconnected genes. Discretized and association rule mining was used to find association between genes thereby predicting the putative function of unannotated genes. Results and discussion Among the significantly expressed chemosensory genes (FDR < 0.05) in response to Ɛ-nonalactone were gustatory receptors (GrIA and Gr28b), ionotrophic receptors (Ir41a and Ir75a), odorant binding proteins (Obp99b, Obp99d, Obp59a and Obp28a) and the odorant receptor (Or67d). Several non-chemosensory genes with no assigned function in the NCBI database were co-expressed with the chemosensory genes. Exposure to a repellent (δ-nonalactone) did not show any significant change between the treatment and control samples. We generated a coexpression network with 276 edges and 130 nodes. Genes CAH3, Ahcy, Ir64a, Or67c, Ir8a and Or67a had node degree values above 11 and therefore could be regarded as the top hub genes in the network. Association rule mining showed a relation between various genes based on their appearance in the same itemsets as consequent and antecedent.

The decision to engage in courtship depends on external cues from potential mates and internal cues related to maturation, health, and experience. Hormones allow for coordinated conveyance of such information to peripheral tissues. Here, we show Ecdysis-Triggering Hormone (ETH) is critical for courtship inhibition after completion of copulation in Drosophila melanogaster. ETH deficiency relieves post-copulation courtship inhibition (PCCI) and increases male-male courtship. ETH appears to modulate perception and attractiveness of potential mates by direct action on primary chemosensory neurons. Knockdown of ETH receptor (ETHR) expression in GR32A-expressing neurons leads to reduced ligand sensitivity and elevated male-male courtship. We find OR67D also is critical for normal levels of PCCI after mating. ETHR knockdown in OR67D-expressing neurons or GR32A-expressing neurons relieves PCCI. Finally, ETHR silencing in the corpus allatum (CA), the sole source of juvenile hormone, also relieves PCCI; treatment with the juvenile hormone analog methoprene partially restores normal post-mating behavior. We find that ETH, a stress-sensitive reproductive hormone, appears to coordinate multiple sensory modalities to guide Drosophila male courtship behaviors, especially after mating.

The Drosophila pheromone cis -11-octadecenyl acetate ( c VA) is used as pheromone throughout the melanogaster group and fulfils a primary role in sexual and social behaviours. Here, we found that Drosophila suzukii , an invasive pest that oviposits in undamaged ripe fruit, does not produce c VA. In fact, its production site, the ejaculatory bulb, is atrophied. Despite loss of c VA production, its receptor, Or67d, and cognate sensillum, T1, which are essential in c VA-mediated behaviours, were fully functional. However, T1 expression was dramatically reduced in D. suzukii , and the corresponding antennal lobe glomerulus, DA1, minute. Behavioural responses to c VA depend on the input balance of Or67d neurons (driving c VA-mediated behaviours) and Or65a neurons (inhibiting c VA-mediated behaviours). Accordingly, the shifted input balance in D. suzukii has reversed c VA's role in sexual behaviour: perfuming D. suzukii males with Drosophila melanogaster equivalents of c VA strongly reduced mating rates. c VA has thus evolved from a generic sex pheromone to a heterospecific signal that disrupts mating in D. suzukii , a saltational shift, mediated through offsetting the input balance that is highly conserved in congeneric species. This study underlines that dramatic changes in a species' sensory preference can result from rather ‘simple’ numerical shifts in underlying neural circuits.

Herbivory is a key innovation in insects, yet has only evolved in one-third of living orders. The evolution of herbivory likely involves major behavioral changes mediated by remodeling of canonical chemosensory modules. Herbivorous flies in the genus Scaptomyza (Drosophilidae) are compelling species in which to study the genomic architecture linked to the transition to herbivory because they recently evolved from microbe-feeding ancestors and are closely related to Drosophila melanogaster. We found that Scaptomyza flava, a leaf-mining specialist on plants in the family (Brassicaceae), was not attracted to yeast volatiles in a four-field olfactometer assay, whereas D. melanogaster was strongly attracted to these volatiles. Yeast-associated volatiles, especially short-chain aliphatic esters, elicited strong antennal responses in D. melanogaster, but weak antennal responses in electroantennographic recordings from S. flava. We sequenced the genome of S. flava and characterized this species’ odorant receptor repertoire. Orthologs of odorant receptors, which detect yeast volatiles in D. melanogaster and mediate critical host-choice behavior, were deleted or pseudogenized in the genome of S. flava. These genes were lost step-wise during the evolution of Scaptomyza. Additionally, Scaptomyza has experienced gene duplication and likely positive selection in paralogs of Or67b in D. melanogaster. Olfactory sensory neurons expressing Or67b are sensitive to green-leaf volatiles. Major trophic shifts in insects are associated with chemoreceptor gene loss as recently evolved ecologies shape sensory repertoires.

Abstract The diversity of herbivorous insects is attributed to their propensity to specialize on toxic plants. In an evolutionary twist, toxins betray the identity of their bearers when herbivores coopt them as cues for host-plant finding, but the evolutionary mechanisms underlying this phenomenon are poorly understood. We focused on Scaptomyza flava, an herbivorous drosophilid specialized on isothiocyanate (ITC)-producing (Brassicales) plants, and identified Or67b paralogs that were triplicated as mustard-specific herbivory evolved. Using in vivo heterologous systems for the expression of olfactory receptors, we found that S. flava Or67bs, but not the homologs from microbe-feeding relatives, responded selectively to ITCs, each paralog detecting different ITC subsets. Consistent with this, S. flava was attracted to ITCs, as was Drosophila melanogaster expressing S. flava Or67b3 in the homologous Or67b olfactory circuit. ITCs were likely coopted as olfactory attractants through gene duplication and functional specialization (neofunctionalization and subfunctionalization) in S. flava, a recently derived herbivore.

Abstract Aims The effect of e-cigarettes on atherosclerosis is still a matter of debate. One method that can be used as atherogenic process marker is the expression of Leptin receptors (mRNA-ObR) and aortic calcification. The aim of this study was to compare Leptin receptors (mRNA-ObR) expression and aortic calcification in mice exposed to conventional cigarettes and e-cigarettes. Methods and Results Thirty samples of mice were randomly divided into control group, conventional cigarette exposure group, and e-cigarette exposure group. After 2 months of treatment using a modified smoking chamber, a surgical procedure was performed to remove aortic tissue. This procedure was followed by histopathological examination to discover aortic calcification, and RT-PCR examination to see the expression of mRNA-ObR. The results of post hoc analysis showed that control group and conventional cigarette exposure group had differences in mRNA-ObR expression and aortic calcification [0.030 (0.090-0.046) fg/µl vs 0.332 (0.990-0.537) fg/µl, p = 0.000, in mRNA ObR; and 0.130 ± 0.719% vs 1.678 ± 0.696%, p = 0.000, in aortic calcification], as well as control group and e-cigarette exposure group [0.030 (0.090-0.046) fg/µl vs 0.376 (0.218-0.464) fg/µl, p = 0.000, in mRNA ObR and 0.130±0.719% vs 1.493±0.496%, p = 0.000, in aortic calcification]. Meanwhile, the group with e-cigarette exposure and group with conventional cigarette exposure didn’t show any differences [0.376 (0.218-0.464) fg/µl vs 0.332 (0.990-0.537) fg/µl, p = 0.568, in mRNA ObR and 1.493 ± 0.496% vs 1.678 ± 0.696%, p = 0.889, in aortic calcification]. Conclusion There were no differences in Leptin receptor (mRNA-ObR) expression and aortic calcification in conventional cigarettes and e-cigarettes exposure groups.

Drosophila suzukii (Diptera: Drosophilidae), an invasive pest from Asia, colonized US and Europe in 2008 and since then has economically damaged multi-million commercial fruit production. With fruit-breaking serrated ovipositor the female lays eggs in the unwounded ripening fruits making them unmarketable. To know the genetic likelihood of D. suzukii with other Drosophila species its genome and transcriptome were sequenced. The whole genome was mined to understand the origin, speciation and adaptation and was correlated with the ecology of the species. Genomic analyses revealed that D. suzukii is adapted to temperate climate and has lower selective pressure and gene-sequencing rate compared to its sibling sp. D. biarmipes. From the genomic and ecological studies, one of the objectives was to understand the role of olfaction in host fruit recognition and identify key volatile compound/s involved in female decision-making for oviposition on fresh fruits. Based on gas chromatography mass spectrometer (GC-MS) and GC-electro-antennal detector activity, isoamylacetate was found to be one of the key compounds involved in the oviposition site selection. The phylogenetic analysis revealed that D. suzukii not only possess the full repertoire of genes encoding olfactory receptors activated by isoamyl acetate in D. melanogaster, but showed that Or67a (Or67a1 to Or67a5) is even represented by duplicated copies. Another aim was to investigate the pheromone communication in this species. The extraction and identification of cuticular hydrocarbons from the males inherently showed that the species trans-evolved by terminating the production of sex pheromone cis vaccenyl acetate (cVA), which is used by species throughout melanogaster group, but able to smell it with ‘fewer’ T1 sensilla. Being under highly selective pressure D. suzukii has i) scaled-down the size of ejaculatory bulb in males, ii) fewer T1 tricoid sensilla, and iii) comparatively smaller glomerulus, in the antennal lobe (AL), involved in receiving sensory impulses from T1 sensilla when compared to D. melanogaster. However D. suzukii shares all functional fatty acid synthase (FAS) genes responsible to CH production. On applying D. melanogaster male equivalent synthetic cVA on males of D. suzukii, it significantly reduced the mating acceptance in the females, which otherwise increased in D. melanogaster. Therefore, by adapting not to produce cVA as a sex pheromone D. suzukii tend to avoid competition with congeneric species for oviposition. The whole spectrum of the present and future studies would help to understand the evolution of the olfactory code among the closely related species of Drosophila and, as a consequence, contribute to develop alternative control methods of D. suzukii. Indeed, comparison of D. suzukii with sibling species and D. melanogaster could shed light on the evolution of ecological innovations and help researchers in understanding what makes a species to be an invasive pest