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The sensory system of animals detects a massive and unknown array of chemical cues that evoke a diversity of physiological and behavioural responses. One group of nitrogen-containing carbon ring chemicals—nucleobases—are thought to be involved in numerous behaviours yet have received little attention. We took a top-down approach to examine responses evoked by nucleobases at behavioural, tissue, and gene expression levels. Fish generally avoided nucleobases, and this behaviour, when observed, was driven by purines but not pyrimidines. At the tissue level, olfactory neuron generator potential responses tended to be concentration specific and robust at concentrations lower than amino acid detection ranges. In terms of gene expression, more than 2000 genes were significantly upregulated following nucleobase exposure, some of which were expected (e.g., genes involved in purine binding) and some of which were not (e.g., tubulin-related genes). Humanized RNA pathway analysis showed that we had exposed the animal to a nucleobase. Our data indicate that responses to nucleobase-containing compounds may be highly structure based and are evident from changes in behaviour to mRNA expression. Many of these responses were surprising, and all provide numerous routes for further research endeavour.

Objective: To investigate the action mechanisms of the FZD5 gene in prostate cancer bone metastasis and search for some new treatments for this disease., Methods: We determined the expression level of the FZD5 gene in prostate cancer PC3 cells and, after transfection of siRNA into the PC3 cells and silence of the FZD5 gene, observed the changes in the migration and proliferation of the cells. We established the model of prostate cancer bone metastasis by tibial injection of prostate cancer cells in the nude mice. Then we injected control siRNA and FZD5-silenced siRNA into the tibia of the mice followed by evaluation of tumor-induced bone destruction by X-ray imaging at 0, 1, and 3 weeks and by HE staining at 3 weeks after injection., Results: After transfection of FZD5-silenced siRNA into the prostate cancer PC3 cells, the expression of the FZD5 gene was decreased about 70%. The rate of cell proliferation was significantly lower in the gene silencing group than in the control (P < 0.05), and that of cell migration dropped by 30% in the former as compared with the latter group at 48 hours after FZD5 silencing (P < 0.05). At 3 weeks after injection of control siRNA or FZD5-silenced siRNA into the tibia of the mice, osteolytic damage was observed in both groups, though less in the FZD5 silencing group, with only a few remaining bone trabeculae visible., Conclusion: Silencing the FZD5 gene can reduce the migration and proliferation of prostate cancer cells, help to suppress bone metastasis and destruction, and thereby improve the survival rate and quality of life of the patients.