Characterization of a lectin from Gonatanthus pumilus D. Don having anti-proliferative effect against human cancer cell lines

A monocot araceous lectin from tubers of Gonatanthus pumilus (GPL) wa earlier purified in our laboratory and reported as T-cell mitogen having homotetrameric structure with subunit molecular mass of 13 kDa. Besides asialofetuin as reported earlier, in the present study it was also inhibited by N-acetyl-D-lactosamine but was non-reactive towards mannose or its derivatives. The lectin is rich in acidic amino acids and cysteine is completely absent. Chemical modification of GPL revealed requirement of tryptophan and tyrosine for lectin sugar interaction. The secondary structure content of GPL, as estimated with CD spectrum in K2D programme, has 73% alpha-helix, 26% beta-sheet and 38% random contributions. Fluorescence spectrum of the lectin solution at 280 nm was typical for tryptophan residues buried inside the protein. Lectin activity decreased when treated with denaturants like guanidine-HCL, urea and thiourea. GPL inhibited the growth of three plant pathogenic fungi namely Colletotrichum lindemuthianum, Fusarium oxysporum and Botrytis cinerea. Out of 11 human cancer cell lines tested, GPL significantly inhibited proliferation of five lines viz. Colo-205, IMR-32, HCT-15, SK-N-SH and HT-29.     

In Vitro Regeneration of a High Oil-yielding Variety of Safflower (Carthamus tinctorius var HUS-305)

A protocol for regular in vitro regeneration of Carthamus tinctorius var HUS-305 is described. The morphogenic response of seed explants and explants from seedlings of different ages were studied on Murashige and Skoog’s medium (MS) supplemented with different growth regulators. The protocol finally standardized involves culture of cotyledonary explants from 2 cm long, 2- to 6-day-old seedlings on MS supplemented with 1.0 mg l^?1 BAP and 0.1 mg l^?1 kinetin. Various other adjuvants viz., adenine sulphate, glutamine and casein hydrolysate were also tested. None of these promoted the caulogenic response significantly. The microshoots could be rooted on medium supplemented with different auxins. The highest rhizogenic response was on 1/2 MS supplemented with 0.2 mg l^?1 NAA.     

Novel cis-acting regulatory elements in wild Oryza species impart improved rice bran quality by lowering the expression of phospholipase D alpha1 enzyme (OsPLDα1)

Molecular Biology Reports - Rice bran oil is good quality edible oil, rich in antioxidants and comprised typically of oleic-linoleic type fatty acids. However, presence of a highly lipolytic enzyme...     

Insights into the Molecular Mechanism of Arsenic Phytoremediation

Journal of Plant Growth Regulation - Arsenic (As) is a widespread carcinogenic pollutant. Phytoremediation is the most suited technology for alleviating the As contamination of soil. In this...     

BST2 regulates interferon gamma-dependent decrease in invasion of HTR-8/SVneo cells via STAT1 and AKT signaling pathways and expression of E-cadherin

ABSTRACT

The mechanism by which interferon-gamma (IFN-γ) downregulates trophoblast invasion needs further investigation. Treatment of HTR-8/SVneo cells with IFN-γ led to a decrease in their invasion concomitant with an increased expression of BST2. Silencing of BST2 by siRNA showed a significant increase in their invasion and spreading after treatment with IFN-γ as well as downregulated expression of E-cadherin. Further, STAT1 silencing inhibited the IFN-γ-dependent increase in the expression of BST2 and E-cadherin. Treatment of HTR-8/SVneo cells with IFN-γ led to the activation of AKT, and its inhibition with PI3K inhibitor abrogated IFN-γ-mediated decrease in invasion/spreading and downregulated BST2 and E-cadherin expression. Collectively, IFN-γ decreases the invasion of HTR-8/SVneo cells by STAT1 and AKT activation via increased expression of BST2 and E-cadherin.     

The Marburgvirus-Neutralizing Human Monoclonal Antibody MR191 Targets a Conserved Site to Block Virus Receptor Binding

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Discovery of Mycobacterium tuberculosis α-1,4-Glucan Branching Enzyme (GlgB) Inhibitors by Structure- and Ligand-based Virtual Screening

GlgB (α-1,4-glucan branching enzyme) is the key enzyme involved in the biosynthesis of α-glucan, which plays a significant role in the virulence and pathogenesis of Mycobacterium tuberculosis. Because α-glucans are implicated in the survival of both replicating and non-replicating bacteria, there exists an exigent need for the identification and development of novel inhibitors for targeting enzymes, such as GlgB, involved in this pathway. We have used the existing structural information of M. tuberculosis GlgB for high throughput virtual screening and molecular docking. A diverse database of 330,000 molecules was used for identifying novel and efficacious therapeutic agents for targeting GlgB. We also used three-dimensional shape as well as two-dimensional similarity matrix methods to identify diverse molecular scaffolds that inhibit M. tuberculosis GlgB activity. Virtual hits were generated after structure and ligand-based screening followed by filters based on interaction with human GlgB and in silico pharmacokinetic parameters. These hits were experimentally evaluated and resulted in the discovery of a number of structurally diverse chemical scaffolds that target M. tuberculosis GlgB. Although a number of inhibitors demonstrated in vitro enzyme inhibition, two compounds in particular showed excellent inhibition of in vivo M. tuberculosis survival and its ability to get phagocytosed. This work shows that in silico docking and three-dimensional chemical similarity could be an important therapeutic approach for developing inhibitors to specifically target the M. tuberculosis GlgB enzyme.     

Computer aided identification of sodium channel blockers in the clinical treatment of epilepsy using molecular docking tools

AbbreviationsAEDs - Antiepileptic drugs, BLAST - Basic Local Alignment Search Tool, CBZ - Carbamazepine, GEFS+ - Generalized Epilepsy with Febrile Seizures Plus, GPCR - G Protein Coupled Receptor, Nav - Sodium channel with specific voltage conduction, PDB - Protein Data Bank, PHT - Phenytoin, PIR - Protein Information resources, SAVES - Structural Analysis and Verification Server, VGSC - Voltage-gated Sodium channels.     

Isolation of an N-acetyl-D-glucosamine specific lectin from the rhizomes of Arundo donax with antiproliferative activity

A lectin with antiproliferative activity towards human cancer cell lines and mitogenic towards human peripheral blood mononuclear cells was purified from the rhizomes of Arundo donax (Linn.) by affinity chromatography on N-acetyl-d-glucosamine linked to epoxy-activated sepharose-6B. The pure preparation apparently yielded a single band of approximately 15 kDa on SDS-PAGE, pH 8.3, under both reducing and non-reducing conditions. The molecular mass of native lectin was 32 kDa as determined by gel filtration chromatography. This showed the lectin to be a dimer, with subunits not held together by disulphide linkages. The A. donax lectin (ADL) agglutinated rabbit erythrocytes and the agglutination was inhibited by N-acetyl-d-glucosamine and its di- and trimer. The lectin was thermostable upto 55 degrees C and showed optimum activity in the range of pH 7.0-9.0 and comprised of 2.1% carbohydrate content.