Aurora kinase A inhibitors: identification, SAR exploration and molecular modeling of 6,7-dihydro-4H-pyrazolo-[1,5-a]pyrrolo[3,4-d]pyrimidine-5,8-dione scaffold

Tricyclic 6,7-dihydro-4H-pyrazolo[1,5-a]pyrrolo[3,4-d]pyrimidine-5,8-dione was identified as a novel scaffold for Aurora kinase A inhibition through virtual screening. SAR exploration coupled with molecular modeling of 8a reveals the minimum pharmacophore requirements for Aurora kinase A inhibition.     

TRPC1 inhibits apoptotic cell degeneration induced by dopaminergic neurotoxin MPTP/MPP

Disturbances in Ca²⁺ homeostasis have been implicated in a variety of neuropathological conditions including Parkinson's disease (PD). However, the importance of store-operated Ca²⁺ entry (SOCE) channels in PD remains to be investigated. In the present study, we have scrutinized the significance of TRPC1 in 1-methyl-4-phenyl-1,2,3,6-tetrahyrdro-pyridine (MPTP)-induced PD using C57BL/6 animal model and PC12 cell culture model. Both sub-acute and sub-chronic treatments of MPTP significantly reduced TRPC1, and tyrosine hydroxylase levels, but not TRPC3, along with increased neuronal death. Furthermore, MPTP induces mitochondrial dysfunction, which was associated with reduced mitochondrial membrane potential, decreased level of Bcl₂, Bcl-xl, and an altered Bcl-xl/Bax ratio thereby initiating apoptosis. Importantly, TRPC1 overexpression in PC12 cells showed significant protection against MPP⁺ induced neuronal apoptosis, which was attributed to the restoration of cytosolic Ca²⁺ and preventing loss of mitochondrial membrane potential. Silencing of TRPC1 or addition of TRPC1 channel blockers decreased mitochondrial membrane potential, whereas activation of TRPC1 restored mitochondrial membrane potential in cells overexpressing TRPC1. TRPC1 overexpression also inhibited Bax translocation to the mitochondria and thereby prevented cytochrome c release and mitochondrial-mediated apoptosis. Overall, these results provide compelling evidence for the role of TRPC1 in either onset/progression of PD and restoration of TRPC1 levels could limit neuronal degeneration in MPTP mediated PD.     

Characterization of plant-growth promoting diazotrophic bacteria isolated from field grown Chinese cabbage under different fertilization conditions

Diazotrophic bacteria isolated from the rhizosphere of Chinese cabbage were assessed for other plant growth promoting characteristics viz., production of IAA, ethylene, ACC deaminase, phosphate solubilization, and gnotobiotic root elongation. Their effect on inoculation to Chinese cabbage was also observed under growth chamber conditions. A total of 19 strains that showed higher nitrogenase activity identified by 16S rRNA gene sequence analysis were found to be the members of the genera Pseudomonas and Agrobacterium belonging to α- and γ-Proteobacteria groups. These strains were also efficient in producing IAA and ACC deaminase though they produced low levels of ethylene and no phosphate solubilization. In addition, inoculation of selected diazotrophic bacterial strains significantly increased seedling length, dry weight, and total nitrogen when compared to uninoculated control. The colonization of crop plants by diazotrophic bacteria can be affected by many biotic and abiotic factors, and further studies are oriented towards investigating the factors that could influence the establishment of a selected bacterial community.     

Hesperidin, a flavanone glycoside, on lipid peroxidation and antioxidant status in experimental myocardial ischemic rats

Myocardial infarction continues to be a leading cause of mortality world-wide. Novel therapies are needed to treat the myocardial ischemia. This study was undertaken to evaluate the cardioprotective role of hesperidin on isoproterenol-induced myocardial ischemia in rats. Myocardial ischemia was induced by subcutaneous injection of isoproterenol hydrochloride (85 mg/kg body weight), for two consecutive days. Isoproterenol-administered rats showed elevated levels of cardiac markers (aspartate transaminase, alanine transaminase, lactate dehydrogenase, creatine kinase, creatine kinase-MB, cardiac troponins T and I) when compared with control and hesperidin treatment groups (100, 200 and 400 mg/kg body weight). The serum levels of cardiac markers were significantly reduced at the doses of 200 mg and 400 mg. All further experiments were carried out at the 200 mg dose. Lipid peroxidation markers (thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes) were elevated significantly in the plasma and heart whereas non-enzymic antioxidants (vitamin C, vitamin E and reduced glutathione) were decreased significantly. Activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase declined significantly in the heart of ischemic rats. However, after hesperidin treatment, all the above parameters reverted to normal levels. This study demonstrated that the cardioprotective effect of hesperidin on ischemic rats could be due to its anti-lipid peroxidative and antioxidant properties.     

Biogenic synthesis of <Emphasis Type="Italic">Marsilea quadrifolia</Emphasis> gold nanoparticles: a study of improved glucose utilization efficiency on 3T3-L1 adipocytes

This study aims mainly to provide an insight and understanding of the effect of glucose utilization efficiency of biogenic gold nanoparticles (GNPs) synthesized through the mediation of Marsilea quadrifolia (M. quadrifolia) methanol extract on 3T3-L1 adipocytes. The biosynthesized GNPs were characterized by UV visible spectrophotometry and FTIR. Simultaneously, the nature, stability, and morphological characteristics were analyzed by XRD, TG-DTA, SEM-EDS, HRTEM, and SAED. The results of characterization studies were used to assess the properties of GNPs. The in vitro cytotoxicity screening indicates that 100 μM of biogenic GNPs were displayed 71.23 ± 1.56% of cellular viability in 3T3-L1 adipocyte cells. Subsequently, increased glucose utilization of biosynthesized GNPs based on a dose-dependent manner on 3T3-L1 has also been demonstrated. The effect of GNPs (30 μg) on glucose uptake was higher than that of insulin and metformin. Moreover, the observed results clearly highlight that the biogenic GNPs have higher efficiency of glucose utilization and cellular viability in 3T3-L1 adipocytes with lower toxicity.     

Overexpression of an Arabidopsis thaliana galactinol synthase gene improves drought tolerance in transgenic rice and increased grain yield in the field

Drought stress has often caused significant decreases in crop production which could be associated with global warming. Enhancing drought tolerance without a grain yield penalty has been a great challenge in crop improvement. Here, we report the Arabidopsis thaliana galactinol synthase 2 gene (AtGolS2) was able to confer drought tolerance and increase grain yield in two different rice (Oryza sativa) genotypes under dry field conditions. The developed transgenic lines expressing AtGolS2 under the control of the constitutive maize ubiquitin promoter (Ubi:AtGolS2) also had higher levels of galactinol than the non‐transgenic control. The increased grain yield of the transgenic rice under drought conditions was related to a higher number of panicles, grain fertility and biomass. Extensive confined field trials using Ubi:AtGolS2 transgenic lines in Curinga, tropical japonica and NERICA4, interspecific hybrid across two different seasons and environments revealed the verified lines have the proven field drought tolerance of the Ubi:AtGolS2 transgenic rice. The amended drought tolerance was associated with higher relative water content of leaves, higher photosynthesis activity, lesser reduction in plant growth and faster recovering ability. Collectively, our results provide strong evidence that AtGolS2 is a useful biotechnological tool to reduce grain yield losses in rice beyond genetic differences under field drought stress.     

An efficient in vitro system for somatic embryogenesis and podophyllotoxin production in Podophyllum hexandrum Royle

Podophyllum hexandrum Royle known as Indian mayapple is an important medicinal plant found only in higher altitudes (2,700 to 4,200 m) of the Himalayas. The highly valued anticancer drug Podophyllotoxin is obtained from the roots of this plant. Due to over exploitation, this endemic plant species is on the verge of extinction. In vitro culture for efficient regeneration and the production of podophyllotoxin is an important research priority for this plant. Hence, in the present study, an efficient plant regeneration system for mass multiplication through somatic embryogenesis was developed. We have screened P. hexandrum seeds collected from three different regions in the Himalayas to find their regenerative potentials. These variants showed variation in germination percentage as well as somatic embryogenic frequency. The seeds collected from the Milam area of Pithoragarh district showed better germination response (99.3 %) on Murashige and Skoog (MS) medium fortified with Gibberellic acid (GA₃ [5 mg/l]) and higher direct somatic embryogenic frequency (89.6 %). Maximum production of embryogenic callus (1.2 g fresh weight [FW]) was obtained when cotyledons containing the direct somatic embryo clusters were cultured in MS medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D [1.5 mg/l]) after 4 week of culture in complete darkness. In the present investigation, somatic embryogenesis was accomplished either by direct organogenesis or callus mediated pathways. The latter method resulted in a higher frequency of somatic embryo induction in hormone-free MS medium yielding 47.7 embryos/50 mg of embryogenic callus and subsequent germination in MS medium supplemented with GA₃ (5 mg/l). Seventy-nine percent of embryos attained complete maturity and germinated into normal plants with well-developed roots. Systematic histological analysis revealed the origin of somatic embryo and their ontogenesis. The higher level of podophyllotoxin (1.8 mg/g dry weight [DW]) was recorded in germinated somatic embryos when compared to field grown plants. The present system can be widely used for mass propagation, transgenic recovery, and podophyllotoxin production for commercial utilization.     

Glutathione peroxidase3 of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> protects phospholipids during cadmium-induced oxidative stress

The present study was undertaken to determine the role of glutathione peroxidase3 (gpx3) in phospholipid protection in cells. Wild-type (WT) cells showed an overall increase in phospholipids upon 50 μM cadmium (Cd)-treatment, whereas an untreated gpx3Δ strain showed a drastic reduction in overall phospholipids which was further reduced with 50 μM Cd. In WT cells, Cd-exposure increased the short chain fatty acids and decreased the unsaturated fatty acids and the magnitude was high in Cd-treated gpx3Δ cells. Purified recombinant gpx3p showed higher activity with phospholipid hydroperoxides than shorter hydroperoxides. An increase in gpx activity was observed in Cd-treated WT cells and no such alteration was observed in gpx3Δ. WT cells treated with Cd showed an increase in MDA over untreated, while untreated gpx3Δ cells themselves showed a higher level of MDA which was further enhanced with Cd-treatment. Iron, zinc and calcium levels were significantly altered in WT and gpx3Δ cells during Cd-treatment.