Stereoselective HPLC separation of alvimopan on cellulose‐based immobilized polysaccharide as a chiral stationary phase

Chiral separation by normal phase high performance liquid chromatography is one of the most powerful technique to quantify the chiral purity of the compounds. In this study, a novel, simple, and specific analytical method was proposed to ascertain the chiral purity of alvimopan (ALV). The normal phase HPLC method was developed based on cellulose tris (3,5‐dichlorophenylcarbamate) stationary phase. The separation of ALV isomers achieved by using column CHIRALPAK IC (250 × 4.6 mm, 5 μm), mobile phase n‐hexane: isopropyl alcohol: ethanol: diethylamine (650:200:150:5 v/v), column oven temperature 30°C, flow rate 1.0 mL min^?1, injection volume was 10 μL, chromatographic response monitored at 273 nm. The developed method was validated as per the ICH guidelines and found precise, accurate, and linear. The advantage of the method is a good separation of ALV isomers within 35 minutes of the analysis time. Therefore, this method is suitable for routine determination of chiral purity of ALV active pharmaceutical ingredient.     

Differential affinity of natural haemagglutinin of Macrobrachium rosenbergii towards vertebrate erythrocytes: effect of sex, size and moult stage on haemagglutination titre

Lectins play important role in innate immunity of animals. The affinity of the natural haemagglutinin of the giant freshwater prawn Macrobrachium rosenbergii towards vertebrate erythrocytes and its level with relation to sex, size and moult stages were studied. The strongest agglutinating titres in haemolymph of prawns were marked against guinea pig, chicken, Clarias batrachus, and rabbit erythrocytes, and the weakest towards cattle, dog, horse and goat erythrocytes. A moderately agglutinating titre was evident in duck and human erythrocytes. The haemolymph of adult, male or intermoult stage prawns weighing more than 100 g had the highest haemagglutinating activity as compared to their respective counterparts with varied responses observed towards various erythrocytes.     

A tick antioxidant facilitates the Lyme disease agent's successful migration from the mammalian host to the arthropod vector

The tick Ixodes scapularis is an efficient vector for microbes, including the Lyme disease agent Borrelia burgdorferi. Ticks engorging on vertebrates induce recruitment of inflammatory cells to the bite site. For efficient transmission to the vector, pathogens have to traffic through this complex feeding site while avoiding the deleterious effects of immune cells. We show that a tick protein, Salp25D, plays a critical role-in the mammalian host-for acquisition of Borrelia burgdorferi by the vector. Silencing salp25D in tick salivary glands impaired spirochete acquisition by ticks engorging on B. burgdorferi-infected mice. Immunizing mice against Salp25D also decreased Borrelia acquisition by I. scapularis. Salp25D detoxified reactive oxygen species at the vector-pathogen-host interface, thereby providing a survival advantage to B. burgdorferi at the tick feeding site in mice. These data demonstrate that pathogens can exploit arthropod molecules to defuse mammalian responses in order to successfully enter the vector.     

Molecular dynamics of interaction of Sesamin and related compounds with the cancer marker β-catenin: an in silico study

By virtue of their regulatory role in the biological process, certain protein–protein complexes form potential targets for designing and discovery of drugs. Alteration set in the controlled formation of such complexes results in dysregulation of several metabolic processes, leading to diseased condition. β-catenin/Tcf4 complex is one such protein–protein complex found altered in colorectal epithelial cells resulting in activation of target genes leading to cancer. Recently, certain lignans from seeds of the oil crop sesame were found inhibiting initiation and progression of this type of cancer. Molecular mechanism involved in the process, however, is not yet known. By an in silico study, we present here a possible mechanism of interaction between the sesame lignans and β-catenin leading to inhibition of formation of the said complex, thereby elevating some of these ligands as potential lead molecules in the development of drugs for treatment of colon cancer. To achieve this objective, we performed docking, molecular dynamics simulation, and binding free energy analysis of target–ligand complexes. Using computational alanine scanning approach, the key pocket residues of β-catenin that interact with Tcf4 in the formation of complex were identified. The test molecules were initially evaluated for their drug-like properties by application of Lipinski’s rule of five. Results of this study revealed that Sesamin, a furofuran lignan from sesame, has the highest affinity for β-catenin particularly with its residues that interact with Tcf4 and thus serving as a potential lead molecule for development of a drug for colon cancer.     

Enhanced production of cellulase-free thermostable xylanase by Bacillus pumilus ASH and its potential application in paper industry

A very high level of cellulase-free, thermostable xylanase has been produced from newly isolated strain of Bacillus pumilus under submerged fermentation in a basal medium supplemented with wheat bran (2%, w/v) pH 8.0 and at 37 °C. After optimization of various production parameters, an increase of nearly 13-fold in xylanase production (5407 IU/ml) was achieved. The produced xylanase is stable in neutral to alkaline pH region at 70 °C. The suitability of this xylanase for use in the bioleaching of eucalyptus Kraft pulp was investigated. A xylanase dose of 5 IU/g of oven dried pulp of 10% consistency exhibited the optimum bleach boosting of the pulp at pH 7.0 and 60 °C after 180 min of treatment. An increase of 5% in brightness along with an increase of 21% and 28% in whiteness and fluorescence respectively, whereas 18% decrease in the yellowness of the biotreated pulp was observed. Enzyme treated pulp when subjected to chemical bleaching, resulted in 20% reduction in chlorine consumption and up to 10% reduction in consumption of chlorine dioxide. Also a reduction of about 16% in kappa number and 83% in permanganate number, along with a reduction in COD value and significant improvement in various pulp properties, viz. viscosity, tensile strength, breaking length, burst factor, burstness, tear factor and tearness were observed in comparison to the conventional chemical bleaching.     

Interleukin-1beta increases expression and activity of matrix metalloproteinase-2 in cardiac microvascular endothelial cells: role of PKCalpha/beta1 and MAPKs

Matrix metalloproteinases (MMPs), a family of extracellular endopeptidases, are implicated in angiogenesis because of their ability to selectively degrade components of the extracellular matrix. Interleukin-1 (IL-1), increased in the heart post-myocardial infarction (post-MI), plays a protective role in the pathophysiology of left ventricular (LV) remodeling following MI. Here we studied expression of various angiogenic genes affected by IL-1 in cardiac microvascular endothelial cells (CMECs) and investigated the signaling pathways involved in the regulation of MMP-2. cDNA array analysis of 96 angiogenesis-related genes indicated that IL-1 modulates the expression of numerous genes, notably increasing the expression of MMP-2, not MMP-9. RT-PCR and Western blot analyses confirmed increased expression of MMP-2 in response to IL-1. Gelatin in-gel zymography and Biotrak activity assay demonstrated that IL-1 increases MMP-2 activity in the conditioned media. IL-1 activated ERK1/2, JNKs, and protein kinase C (PKC), specifically PKC/₁, and inhibition of these cascades partially inhibited IL-1-stimulated increases in MMP-2. Inhibition of PKC/₁ failed to inhibit ERK1/2. However, concurrent inhibition of PKC/₁ and ERK1/2 almost completely inhibited IL-1-mediated increases in MMP-2 expression. Inhibition of p38 kinase and nuclear factor-B (NF-B) had no effect. Pretreatment with superoxide dismutase (SOD) mimetic, MnTMPyP, increased MMP-2 protein levels, whereas pretreatment with SOD and catalase mimetic, EUK134, partially inhibited IL-1-stimulated increases in MMP-2 protein levels. Exogenous H₂O₂ significantly increased MMP-2 protein levels, whereas superoxide generation by xanthine/xanthine oxidase had no effect. This in vitro study suggests that IL-1 modulates expression and activity of MMP-2 in CMECs. MMP-2; protein kinase C; ERK1/2; JNK     

Stimulation by abscisic acid of the activity of phosphoenolpyruvate carboxylase in leaf disks of <Emphasis Type="Italic">Amaranthus hypochondriacus</Emphasis> L., C<Subscript>4</Subscript> plant: role of pH and protein levels

C₄ plants can more efficiently fix carbon in drought, high temperatures, and limitations of nitrogen or CO₂. Primary carboxylation is mediated by phosphoenolpyruvate carboxylase (PEPC, 4.1.1.31) in mesophyll cytosol of C₄ plants. Studies on hormonal regulation of C₄ PEPC have been quite limited. We have examined the activity/regulation of PEPC by abscisic acid (ABA), a plant hormone, in the leaves of Amaranthus hypochondriacus. PEPC activity was enhanced upon 1-h incubation with 20 μM ABA by about 30% in dark and more than 2-fold in light. Glucose-6-phosphate activation of PEPC was enhanced, and sensitivity to l-malate was decreased after ABA treatment. Butyric acid (a weak acid) decreased PEPC activity and restricted the stimulation by ABA. In contrast, methylamine (an alkalinizing agent) increased the PEPC activity and enhanced the effect of ABA. ABA increased the levels of PEPC protein as well as its mRNA. Butyric acid/methylamine modulated the changes induced by ABA of PEPC protein and mRNA levels, indicating that acidification/alkalinization of leaf disks was very important. Our results emphasize the marked modulation of PEPC in C₄ plants, by ABA. Such modulation by ABA could be significant when C₄ plants are under water stress, when ABA is known to accumulate. When present, cycloheximide decreased the PEPC protein levels and restricted the extent of activation by ABA. We conclude that the enhancement by ABA of PEPC activity depends on cellular alkalinization as well as elevated PEPC protein levels.     

SCAR Marker Development for the Identification of Elite Germplasm of Moringa Oleifera Lam.-A Never Die Plant

Plant Molecular Biology Reporter - Moringa oleifera Lam. (drumstick) belongs to the family Moringaceae that is originated from sub-Himalayan tracts of Northern India distributed worldwide in the...     

Ferroptotic agent-induced endoplasmic reticulum stress response plays a pivotal role in the autophagic process outcome

Ferroptosis has been reported as a unique form of cell death. However, in recent years, researchers have increasingly challenged the uniqueness of ferroptosis compared to other types of cell death. In this study, we examined whether ferroptosis shares cell death pathways with other types of cell death, especially autophagy, via the autophagic process. Here, we observed that ferroptosis inducers (artesunate [ART] and erastin [ERA]) and autophagy inducers (bortezomib [BOR] and XIE62-1004) led to autophagosome formation via the endoplasmic reticulum (ER) stress response. Unlike XIE62-1004, ART, ERA, and BOR, which affect glutathione production or utilization, induced oxidative stress responses—an increase in the levels of heme oxygenase-1 and lipid peroxidation. Oxidative stress responses were attenuated by deletion of autophagy-related gene-5 or treatment with autophagy inhibitors (bafilomycin and chloroquine). Our studies provide an overview of common death pathways—the ER stress response-associated autophagic process in ferroptosis and autophagy. We also highlight the role played by glutathione redox system in the outcome of the autophagic process.