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Nandi, D.

Publications and source records attributed to Nandi, D..

20 records · Page 2Linked to original sources

A sensory ecological perspective on mate sampling strategies: simulation models and an empirical test

Long-range communication signals play a central role in mate search and mate choice across a wide range of taxa. Among the different aspects of mate choice, the strategy an individual employ to search for potential mates (mate sampling) has been less explored despite its significance. Although analytical models of mate sampling have demonstrated significant differences in individual fitness returns for different sampling strategies, these models have rarely incorporated relevant information on the ecology of signalers and sensory physiology of receivers, both of which can profoundly influence which sampling strategy is optimal. In this study, we used simulation models to compare the costs and benefits of different female mate sampling strategies in an acoustically communicating field cricket (Plebeiogryllus guttiventris) by incorporating information on relative spacing of callers in natural choruses, their signal intensity and the effect of signal intensity on female phonotaxis behaviour. Mating with the louder caller that the female first approaches emerged as the optimal strategy, thus reflecting the importance of physiological mechanisms of sound signal localization (passive attraction) over active sampling. When tested empirically in the field, female behaviour was consistent with passive attraction.

evolutionary biology↗

Receptor guanylyl cyclase C confers protection during oral Salmonella Typhimurium infection by attenuating ileal damage and enhancing cytokine and antimicrobial peptide production

Non-typhoidal Salmonella disease contributes towards significant morbidity and mortality across the world. Host factors including IFN-{gamma}, TNF- and gut microbiota, significantly influence the outcome of Salmonella pathogenesis. However, the entire repertoire of host protective mechanisms contributing to Salmonella pathogenicity is not completely appreciated. Here, we have investigated the roles of receptor guanylyl cyclase C (GC-C) that is predominantly expressed in the intestine, and regulates intestinal cell proliferation and fluid-ion homeostasis. Mice deficient in GC-C (Gucy2c-/-) displayed accelerated mortality following infection via the oral route, in spite of possessing comparative systemic Salmonella infection burden. Survival following intra-peritoneal infection remained similar, indicating that GC-C offered protection via a gut-mediated response. Serum cortisol was higher in Gucy2c-/- mice, in comparison to wild type (Gucy2c+/+) mice, and an increase in infection-induced thymic atrophy, with loss in immature CD4+CD8+ double positive thymocytes, was observed. Accelerated and enhanced damage in the ileum, including submucosal edema, epithelial cell damage, focal tufting and distortion of villus architecture, was seen in Gucy2c-/- mice, concomitant with a larger number of ileal tissue-associated bacteria. Transcription of key mediators in Salmonella-induced inflammation (IL-22/Reg3{beta}) were altered in Gucy2c-/- mice in comparison to Gucy2c+/+ mice. A reduction in fecal Lactobacilli, which are protective against Salmonella infection, was observed in Gucy2c-/- mice. Gucy2c-/- mice cohoused with wild type mice continued to show reduced Lactobacilli and increased susceptibility to infection. Our study therefore suggests that receptor GC-C confers a survival advantage during gut-mediated S. Typhimurium pathogenesis, presumably by regulating Salmonella-effector mechanisms and maintaining a beneficial microbiome.

microbiology↗