Thiamine Deficiency Induced Dietary Disparity Promotes Oxidative Stress and Neurodegeneration.

Thiamine or vitamin B1 is a well known coenzyme and nutrient necessary for the assembly and right functioning of several enzymes involved in the energy metabolism. The present study evaluates oxidative stress and prevalence of neurodegenerative conditions in the brain following TD. The study was carried out on mice (Musmusculus) in three groups, namely control and thiamine-deficient group for 8 (TD 8) and 10 (TD 10) days. Lipid peroxidation was determined in terms of reduced glutathione (GSH) and thiobarbituric acid reactive substance (TBARS). The level of antioxidant enzymes such as catalase (CAT), glutathione reductase, glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione transferase (GST) were measured along with histopathological studies in all the groups. There was significant increase in the TBARS levels in group II (TD 8) and group III (TD 10) animals in comparison to controls (Group I). The GSH levels were found to be lower in both the treated groups. The level of antioxidant enzymes CAT (p < 0.001), glutathione reductase (p < 0.001), GPx (p < 0.001), SOD (p < 0.0001) were found to be significantly reduced in group III (TD 10) in comparison to controls. Histopathological studies showed moderated to extensive neuronal loss in group II and group III in comparison to control group. The increase in LPO and reduction in enzymes CAT, glutathione reductase, GPx, SOD, and GST following TD suggests mitochondrial dysfunction, neuronal loss acute oxidative stress that may impair the functioning of the brain along with the rise of neurodegenerative conditions in the affected animals.

Nectarless flowers: ecological correlates and evolutionary stability.

In animal-pollinated flowers, the pollinators cannot detect the presence of nectar before entering flowers, and therefore flowers may cheat by not producing nectar. An earlier model suggested that a mixed strategy of producing nectarful and nectarless flowers would be evolutionarily stable. Here we compare nectarless flowers as a cheating strategy with three competing hypotheses namely "visit-more-flowers", "cross-pollination enhancement" and "better contact". We collected field data on 28 species of plants to test some of the differential predictions of the hypotheses. Nectarless flowers were detected in 24 out of 28 plant species. Correlations of percent nectarless flowers with floral and ecological variables support the cheater flower hypothesis. We further model the cost-benefits of cheating and show that an evolutionary stable ratio of nectarless to nectarful flowers can be reached. The equilibrium ratio is mainly decided by factors associated with pollinator density and pollinator learning.