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High-fat diet (HFD)-induced obesity is a risk factor for cognitive impairment in Alzheimer's disease (AD). It has been reported that two typical neuropathological markers of AD, β-amyloid (Aβ) peptide and hyperphosphorylated protein tau can cause neuronal apoptosis via oxidative stress, which ultimately leads to cognitive dysfunction. In this study, we tried to explore the molecular pathway underlying memory impairment in young AD transgenic mice model in response to HFD. We maintained non-transgenic control mice (non-Tg) and triple transgenic AD (3xTg-AD) mice aged 8 weeks on either normal diet (ND) containing 10% fat or HFD (60% fat) for 16 weeks. Cognitive functions were evaluated by Morris water maze and Y-maze tests. Behavioral tests showed a significant memory impairment in 3xTg-AD mice fed with HFD. HFD did not alter the levels of Aβ and phospho-tau protein in the cortical region regardless of groups. However, 3xTg-AD mice fed with HFD exhibited increased neuronal oxidative stress and apoptosis as assessed by augmentation of lipid peroxidation, activation of caspase-3 and elevated ratio of Bax/Bcl-2. Furthermore, HFD markedly reduced the activation of redox-sensitive transcription factor NF-E2-related factor 2 (Nrf2) by suppressing its up-stream regulatory protein kinase B/Akt as well as down-stream targets such as heme oxygenase-1 and manganese superoxide dismutase in these mice. Our findings suggest that HFD may accelerate cognitive impairment by enhancing oxidative stress and aggravating neuronal apoptosis via inactivation of Nrf2 signaling pathway.

Abiotic stresses including drought, salinity, heat, cold, flooding, and ultraviolet radiation causes crop losses worldwide. In recent times, preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance. However, the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities. Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance. Recent investigations have shown that phytohormones, including the classical auxins, cytokinins, ethylene, and gibberellins, and newer members including brassinosteroids, jasmonates, and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants. In this review, we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance, besides their engineering for conferring abiotic stress tolerance in transgenic crops. We also describe recent successes in identifying the roles of phytohormones under stressful conditions. We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.

Andrographis paniculata (Acanthaceae) is a well-known medicinal plant and is conventionally used in herbal medicine for the treatment of several diseases such as cancer, metabolic disorders, skin infections, respiratory tract infections, etc. In this present study, ethyl acetate extract of A. paniculata was used to test its efficacy on controlling growth and biofilm formation in multi drug resistant pathogenic strains of Escherichia coli through micro-dilution method. Antibiotic susceptibility screening through disc diffusion revealed that these E. coli strains were resistant towards 13 out of 15 antibiotics used. It was found that 250 and 500 μg/ml of crude ethyl acetate (CEA) extract effectively reduced the growth and biofilm formation as compared to 62 and 125 μg/ml. The strains treated with CEA extract of A. paniculata reduced extracellular polysaccharide (EPS) production and downregulated the expression of AmpC gene. The results suggested that CEA extract of A. paniculata can be explored to utilize as an alternative to antibiotics.