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.     

A first insight into population structure and linkage disequilibrium in the US peanut minicore collection

Knowledge of genetic diversity, population structure, and degree of linkage disequilibrium (LD) in target association mapping populations is of great importance and is a prerequisite for LD-based mapping. In the present study, 96 genotypes comprising 92 accessions of the US peanut minicore collection, a component line of the tetraploid variety Florunner, diploid progenitors A. duranensis (AA) and A. ipaënsis (BB), and synthetic amphidiploid accession TxAG-6 were investigated with 392 simple sequence repeat (SSR) marker bands amplified using 32 highly-polymorphic SSR primer pairs. Both distance- and model-based (Bayesian) cluster analysis revealed the presence of structured diversity. In general, the wild-species accessions and the synthetic amphidiploid grouped separately from most minicore accessions except for COC155, and were eliminated from most subsequent analyses. UPGMA analysis divided the population into four subgroups, two major subgroups representing subspecies fastigiata and hypogaea, a third group containing individuals from each subspecies or possibly of mixed ancestry, and a fourth group, either consisting of COC155 alone if wild species were excluded, or of COC155, the diploid species, and the synthetic amphidiploid. Model-based clustering identified four subgroups- one each for fastigiata and hypogaea subspecies, a third consisting of individuals of both subspecies or of mixed ancestry predominantly from Africa or Asia, and a fourth group, consisting of individuals predominantly of var fastigiata, peruviana, and aequatoriana accessions from South America, including COC155. Analysis of molecular variance (AMOVA) revealed statistically-significant (P < 0.0001) genetic variance of 16.87% among subgroups. A total of 4.85% of SSR marker pairs revealed significant LD (at r² ≥ 0.1). Of the syntenic marker pairs separated by distances < 10 cM, 11–20 cM, 21–50 cM, and > 50 cM, 19.33, 5.19, 6.25 and 5.29% of marker pairs were found in strong LD (P ≤ 0.01), in accord with LD extending to great distances in self pollinated crops. A threshold value of r² > 0.035 was found to distinguish mean r² values of linkage distance groups statistically from the mean r² values of unlinked markers; LD was found to extend to 10 cM over the entire minicore collection by this criterion. However, there were large differences in r² values among marker pairs even among tightly-linked markers. The implications of these findings with regard to the possibility of using association mapping for detection of genome-wide SSR marker-phenotype association are discussed.     

Correlation of Trace Elemental Profiles in Blood Samples of Indian Patients with Leukoplakia and Oral Submucous Fibrosis

In order to ascertain possible correlation between alterations in trace elemental profile and the progression or regression of two most common potentially malignant disorders affecting oral cavity, namely oral submucous fibrosis and leukoplakia, blood from 60 patients from each group of patients as well from 30 healthy individuals was analyzed for elemental profiling employing EDXRF technique. Out of the 16 detected elements (K, Si, Ca, V, Cr, Ni, Mn, Fe, Cu, Zn, Se, Br, Rb, Sr, Co, and Pb), Mn, Fe, Zn, Br, and Co showed remarkable alteration in their profile in both leukoplakia and oral submucous fibrosis patients with respect to the normal healthy individuals. While Zn, Br, and Fe reflected similar changes--showing gross depletion in both the diseased groups, Mn and Co depicted inverse pattern of alterations in their concentrations in the two types of precancerous disorders when compared to the control subjects.     

Heat stress screening of peanut (<Emphasis Type="Italic">Arachis hypogaea</Emphasis> L.) seedlings for acquired thermotolerance

Heat can be one of the major abiotic stresses that adversely affect crop production worldwide at different stages of development. As field screening for heat tolerance can be inconsistent and seasonally-limited, it is important to develop a reliable protocol under controlled conditions that allows simultaneous screening of multiple genotypes. The objective of this research was to develop a straightforward laboratory protocol using acquired thermotolerance (ATT) in peanut seedlings as a measure of one mechanism of heat stress tolerance. Sixteen genotypes, including selected accessions of the US peanut minicore collection along with standard checks, were evaluated for acquired themotolerance in two independent experiments. A change in the temperature sensitivity of chlorophyll accumulation was used as an indicator of acquired thermotolerance. Pre-incubation at 38°C for 4 h before the 30-min 50°C challenge triggered the acquired thermotolerance system of the leaf disks, resulting in chlorophyll accumulation upon exposure to light. There was considerable variation among genotypes for ATT in both experiments. Genotypic ranking for mean ATT values were highly correlated (0.949) in both experiments. The effect of seed weight on ATT was not significant. This method is relatively simple and inexpensive and can be used to screen a large number of genotypes.     

A new subset of CD103+CD8alpha+ dendritic cells in the small intestine expresses TLR3, TLR7, and TLR9 and induces Th1 response and CTL activity

CD103(+) dendritic cells (DCs) are the major conventional DC population in the intestinal lamina propria (LP). Our previous report showed that a small number of cells in the LP could be classified into four subsets based on the difference in CD11c/CD11b expression patterns: CD11c(hi)CD11b(lo) DCs, CD11c(hi)CD11b(hi) DCs, CD11c(int)CD11b(int) macrophages, and CD11c(int)CD11b(hi) eosinophils. The CD11c(hi)CD11b(hi) DCs, which are CD103(+), specifically express TLR5 and induce the differentiation of naive B cells into IgA(+) plasma cells. These DCs also mediate the differentiation of Ag-specific Th17 and Th1 cells in response to flagellin. We found that small intestine CD103(+) DCs of the LP (LPDCs) could be divided into a small subset of CD8α(+) cells and a larger subset of CD8α(-) cells. Flow cytometry analysis revealed that CD103(+)CD8α(+) and CD103(+)CD8α(-) LPDCs were equivalent to CD11c(hi)CD11b(lo) and CD11c(hi)CD11b(hi) subsets, respectively. We analyzed a novel subset of CD8α(+) LPDCs to elucidate their immunological function. CD103(+)CD8α(+) LPDCs expressed TLR3, TLR7, and TLR9 and produced IL-6 and IL-12p40, but not TNF-α, IL-10, or IL-23, following TLR ligand stimulation. CD103(+)CD8α(+) LPDCs did not express the gene encoding retinoic acid-converting enzyme Raldh2 and were not involved in T cell-independent IgA synthesis or Foxp3(+) regulatory T cell induction. Furthermore, CD103(+)CD8α(+) LPDCs induced Ag-specific IgG in serum, a Th1 response, and CTL activity in vivo. Accordingly, CD103(+)CD8α(+) LPDCs exhibit a different function from CD103(+)CD8α(-) LPDCs in active immunity. This is the first analysis, to our knowledge, of CD8α(+) DCs in the LP of the small intestine.     

Improved production of withanolides in shoot suspension culture of Withania somnifera (L.) Dunal by seaweed extracts

The influence of Gracilaria edulis and Sargassum wightii extracts was investigated for the production of biomass and withanolides in the multiple shoot suspension culture of Withania somnifera. Supplementation of 40 % G. edulis extract in MS liquid medium for 24 h exposure time in the culture recorded the highest biomass accumulation [62.4 g fresh weight and 17.82 g dry weight (DW)] and withanolides production (withanolide A 0.76 mg/g DW; withanolide B 1.66 mg/g DW; withaferin A 2.80 mg/g DW and withanone 2.42 mg/g DW) after 5 weeks of culture, which were 1.45–1.58-fold higher than control culture. This naturally available G. edulis extract-treated multiple shoot suspension culture protocol offers a potential alternative for the optimum production of biomass and withanolides utilizing shake-flasks.