Browsing by Subject "functional"
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Item Social Odors Conveying Dominance and Reproductive information Induce Rapid Physiological and Neuromolecular Changes in a Cichlid Fish(2015-02) Simoes, Jose M.; Barata, Eduardo N.; Harris, Rayna M.; O'Connell, Lauren A.; Hofmann, Hans A.; Oliveira, Rui F.; Harris, Rayna M.; O'Connell, Lauren A.; Hofmann, Hans A.Social plasticity is a pervasive feature of animal behavior. Animals adjust the expression of their social behavior to the daily changes in social life and to transitions between life-history stages, and this ability has an impact in their Darwinian fitness. This behavioral plasticity may be achieved either by rewiring or by biochemically switching nodes of the neural network underlying social behavior in response to perceived social information. Independent of the proximate mechanisms, at the neuromolecular level social plasticity relies on the regulation of gene expression, such that different neurogenomic states emerge in response to different social stimuli and the switches between states are orchestrated by signaling pathways that interface the social environment and the genotype. Here, we test this hypothesis by characterizing the changes in the brain profile of gene expression in response to social odors in the Mozambique Tilapia, Oreochromis mossambicus. This species has a rich repertoire of social behaviors during which both visual and chemical information are conveyed to conspecifics. Specifically, dominant males increase their urination frequency during agonist encounters and during courtship to convey chemical information reflecting their dominance status. Results: We recorded electro-olfactograms to test the extent to which the olfactory epithelium can discriminate between olfactory information from dominant and subordinate males as well as from pre- and post-spawning females. We then performed a genome-scale gene expression analysis of the olfactory bulb and the olfactory cortex homolog in order to identify the neuromolecular systems involved in processing these social stimuli. Conclusions: Our results show that different olfactory stimuli from conspecifics' have a major impact in the brain transcriptome, with different chemical social cues eliciting specific patterns of gene expression in the brain. These results confirm the role of rapid changes in gene expression in the brain as a genomic mechanism underlying behavioral plasticity and reinforce the idea of an extensive transcriptional plasticity of cichlid genomes, especially in response to rapid changes in their social environment.Item Synthesis and Crystal Structures of Lanthanide 4-Benzyloxy Benzoates: Influence of Electron-Withdrawing and Electron-Donating Groups On Luminescent Properties(2009-11) Sivakumar, Sarika; Reddy, M. L. P.; Cowley, Alan H.; Vasudevan, Kalyan V.; Cowley, Alan H.; Vasudevan, Kalyan V.Three new 4-benzyloxy benzoic acid derivatives [4-benzyloxy benzoic acid = HL1; 3-methoxy-4-benzyloxy benzoic acid = HL2; 3-nitro-4-benzyloxy benzoic acid = HL3] have been employed as ligands for the support of six lanthanide coordination compounds [Tb3+ = 1-3; Eu3+ = 4-6] with the aim of testing the influence of electron releasing (-OMe) or electron withdrawing (-NO2) substituents on the photophysical properties. The new complexes have been characterized by a variety of spectroscopic techniques and two of the Tb3+ complexes [1 and 2] have been structurally authenticated by single-crystal X-ray diffraction. Compounds 1 and 2 crystallize in the monoclinic space group P2(1)/n and their molecular structures consist of homodinuclear species that are bridged by two oxygen atoms from two benzoate ligands. In the case of 1, the carboxylate ligands coordinate to the central Tb3+ ion in bidentate chelating and bidentate bridging modes. By contrast, three different coordination modes (bidentate chelating, bidentate bridging and monodentate) are observed in the case of compound 2. Examination of the packing diagrams for 1 and 2 revealed the presence of a one-dimensional molecular array that is held together by intermolecular hydrogen-bonding interactions. The incorporation of an electron-releasing substituent on position 3 of 4-benzyloxy benzoic acid increases the electron density of the ligand and consequently improves the photoluminescence of the Tb3+ complexes. On the other hand, the presence of an electron-withdrawing group at this position dramatically decreases the overall sensitization efficiency of the Tb3+-centered luminescence due to dissipation of the excitation energy by means of a pi*-n transition of the NO2 substituent along with the participation of the ILCT bands. The weaker photoluminescence of the Eu3+ complexes is attributable to the poor match of the triplet energy levels of the 4-benzyloxy benzoic acid derivatives with that of the emitting level of the central metal ion.