Comparison of Barium and Arsenic Concentrations in Well Drinking Water and in Human Body Samples and a Novel Remediation System for These Elements in Well Drinking Water

Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system.     

The molecular mechanism of vernalization in Arabidopsis and cereals: role of Flowering Locus C and its homologs

Winter varieties of plants can flower only after exposure to prolonged cold. This phenomenon is known as vernalization and has been widely studied in the model plant Arabidopsis thaliana as well as in monocots. Through the repression of floral activator genes, vernalization prevents flowering in winter. In Arabidopsis, FLOWERING LOCUS C or FLC is the key repressor during vernalization, while in monocots vernalization is regulated through VRN1, VRN2 and VRN3 (or FLOWERING LOCUS T). Interestingly, VRN genes are not homologous to FLC but FLC homologs are found to have a significant role in vernalization response in cereals. The presence of FLC homologs in monocots opens new dimensions to understand, compare and retrace the evolution of vernalization pathways between monocots and dicots. In this review, we discuss the molecular mechanism of vernalization-induced flowering along with epigenetic regulations in Arabidopsis and temperate cereals. A better understanding of cold-induced flowering will be helpful in crop breeding strategies to modify the vernalization requirement of economically important temperate cereals.     

A mass spectrometry-based high-throughput screening method for engineering fatty acid synthases with improved production of medium-chain fatty acids

Microbial cell factories have been extensively engineered to produce free fatty acids (FFAs) as key components of crucial nutrients, soaps, industrial chemicals, and fuels. However, our ability to control the composition of microbially synthesized FFAs is still limited, particularly, for producing medium-chain fatty acids (MCFAs). This is mainly due to the lack of high-throughput approaches for FFA analysis to engineer enzymes with desirable product specificity. Here we report a mass spectrometry (MS)-based method for rapid profiling of MCFAs in Saccharomyces cerevisiae by using membrane lipids as a proxy. In particular, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) MS was used to detect shorter acyl chain phosphatidylcholines from membrane lipids and a higher m/z peak ratio at 730 and 758 was used as an indication for improved MCFA production. This colony-based method can be performed at a rate of ~2 s per sample, representing a substantial improvement over gas chromatography-MS (typically >30 min per sample) as the gold standard method for FFA detection. To demonstrate the power of this method, we performed site-saturation mutagenesis of the yeast fatty acid synthase and identified nine missense mutations that resulted in improved MCFA production relative to the wild-type strain. Colony-based MALDI-ToF MS screening provides an effective approach for engineering microbial fatty acid compositions in a high-throughput manner.     

Effect of nitric oxide signaling in bacterial-treated soybean plant under salt stress

To understand protective roles of nitric oxide against salt stress, the effects of exogenous sodium nitroprusside on activities of lipoxygenase, peroxidase, phenylalanine ammonialyase, catalase, superoxide dismutase enzymes, proline accumulation, and distribution of sodium in soybean plants under salt were determined. Application of sodium nitroprusside + bacterium enhanced plant growth-promotion characteristics, activities of different enzymes, and proline accumulation in the presence of sodium nitroprusside under salt stress. Treatment with NaCl at 200 mM and sodium nitroprusside (0.1 mM) reduced Na⁺ levels but increased K⁺ levels in leaves in comparison with the NaCl-treated plants. Correspondingly, the plants treated with exogenous sodium nitroprusside and NaCl maintained a lower ratio of [Na⁺]/[K⁺] in NaCl-stressed plants.     

Sources of resistance against post-flowering stalk rots of maize

The post-flowering stalk rots (PFSR) are a complex disease, which are widely distributed in almost all the maize growing regions across the globe. A number of fungi are involved in causing decay of the pith resulting in pre-mature wilting of the plants. Most of the commercially grown cultivars have shown a high level of disease incidence at the grain filling stage. A systematic breeding programme on PFSR was initiated in India in collaboration with Asian Regional Maize Program of CIMMYT. Under this programme, germplasm screening was carried out at four ‘hot spot’ locations in India for different diseases: Hyderabad (Cephalosporium maydis), Udaipur (Fusarium moniliforme), Ludhiana and Delhi (Macrophomina phaseolina). Across the locations, promising maize genotypes were artificially inoculated using the toothpick method, year after year; resistant plants were selfed to derive resistant inbreds. After extensive screening, three resistant lines, namely PFSR-13-5, JCY2-2-4-1-1-1-1 and JCY3-7-1-2-1-b-1, were identified. In addition, the resistance level of five pools/populations; (PFSR (Y)-C1, PFSR (white), Extra-early (White), P-100, P-300 and P-345) was upgraded to an acceptable level. These genotypes may prove useful for utilisation in breeding cultivars for resistance to PFSR.     

Unravelling the beneficial role of microbial contributors in reducing the allelopathic effects of weeds

The field of allelopathy is one of the most fascinating but controversial processes in plant ecology that offers an exciting, interdisciplinary, complex, and challenging study. In spite of the established role of soil microbes in plant health, their role has also been consolidated in studies of allelopathy. Moreover, allelopathy can be better understood by incorporating soil microbial ecology that determines the relevance of allelopathy phenomenon. Therefore, while discussing the role of allelochemicals in plant–plant interactions, the dynamic nature of soil microbes should not be overlooked. The occurrence and toxicity of allelochemicals in soil depend on various factors, but the type of microflora in the surroundings plays a crucial role because it can interfere with its allelopathic nature. Such microbes could be of prime importance for biological control management of weeds reducing the cost and ill effects of chemical herbicides. Among microbes, our main focus is on bacteria—as they are dominant among other microbes and are being used for enhancing crop production for decades—and fungi. Hence, to refer to both bacteria and fungi, we have used the term microbes. This review discusses the beneficial role of microbes in reducing the allelopathic effects of weeds. The review is mainly focused on various functions of bacteria in (1) reducing allelopathic inhibition caused by weeds to reduce crop yield loss, (2) building inherent defense capacity in plants against allelopathic weed, and (3) deciphering beneficial rhizospheric process such as chemotaxis/biofilm, degradation of toxic allelochemicals, and induced gene expression.     

Design and synthesis of tricyclic cores for kinase inhibition

Interest in therapeutic kinase inhibitors continues to grow beyond success in oncology. To date, ATP-mimetic kinase inhibitors have focused primarily on monocyclic and bicyclic heterocyclic cores. We sought to expand on the repertoire of potential cores for kinase inhibition by exploring tricyclic variants of classical bicyclic hinge binding motifs such as pyrrolopyridine and pyrrolopyrazine. Herein we describe the syntheses of eight alternative tricyclic cores as well as in vitro screening results for representative kinases of potential therapeutic interest.     

Electrochemical immunosensor for label free epidermal growth factor receptor (EGFR) detection

This paper presents an electrochemical immune sensor for label free detection of epidermal growth factor receptor (EGFR) by immobilizing anti-EGFR antibody (Anti-EGFRab) on dithiobissuccinimidyl propionate (DTSP) self-assembled monolayer (SAM) on gold (Au) electrode. Electrochemical studies show that increased surface concentration of redox moieties onto Anti-EGFRab/DTSP immuno-electrode leads to high electron transport and improved sensing performance. The antigen-antibody complex demonstrates a high association constant (5×10(12)L/mol) that results in high affinity of Anti-EGFRab to EGFR, confirming that the DTSP-SAM provides a conducive environment for anti-EGFR immobilization. The electrochemical response of EA/Anti-EGFRab/DTSP/Au electrode as a function of EGFR concentrations exhibits a linear range from 1pg/mL to 100ng/mL, a detection limit of 1pg/mL at a sensitivity of 2.02μAM(-1)at a regression coefficient of 0.99.