Xanthomonas sontii sp. nov., a non-pathogenic bacterium isolated from healthy basmati rice (Oryza sativa) seeds from India

Antonie van Leeuwenhoek - We report three yellow-pigmented, Gram-negative, aerobic, rod-shaped, motile bacterial isolates designated as PPL1T, PPL2, and PPL3 from healthy basmati rice seeds....     

Novel insights into the dynamics behavior of glucagon-like peptide-1 receptor with its small molecule agonists

Abstract

The glucagon-like peptide-1 receptor (GLP-1R) is a well-known target of therapeutics industries for the treatment of various metabolic diseases like type 2 diabetes and obesity. The structural–functional relationships of small molecule agonists and GLP-1R are yet to be understood. Therefore, an attempt was made on structurally known GLP-1R agonists (Compound 1, Compound 2, Compound A, Compound B, and (S)-8) to study their interaction with the extracellular domain of GLP-1R. In this study, we explored the dynamics, intrinsic stability, and binding mechanisms of these molecules through computational modeling, docking, molecular dynamics (MD) simulations and molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) binding free energy estimation. Molecular docking study depicted that hydrophobic interaction (pi–pi stacking) plays a crucial role in maintaining the stability of the complex, which was also supported by intermolecular analysis from MD simulation study. Principal component analysis suggested that the terminal ends along with the turns/loops connecting adjacent helix and strands exhibit a comparatively higher movement of main chain atoms in most of the complexes. MM/PBSA binding free energy study revealed that non-polar solvation (van der Waals and electrostatic) energy subsidizes significantly to the total binding energy, and the polar solvation energy opposes the binding agonists to GLP-1R. Overall, we provide structural features information about GLP-1R complexes that would be conducive for the discovery of new GLP-1R agonists in the future for the treatment of various metabolic diseases.

Communicated by Ramaswamy H. Sarma     

Spiro heterocycles as potential inhibitors of SIRT1: Pd/C-mediated synthesis of novel N-indolylmethyl spiroindoline-3,2′-quinazolines

Novel N-indolylmethyl substituted spiroindoline-3,2′-quinazolines were designed as potential inhibitiors of SIRT1. These compounds were synthesized in good yields by using Pd/C–Cu mediated coupling-cyclization strategy as a key step involving the reaction of 1-(prop-2-ynyl)-1′H-spiro[indoline-3,2′-quinazoline]-2,4′(3′H)-dione with 2-iodoanilides. Some of the compounds synthesized have shown encouraging inhibition of Sir 2 protein (a yeast homologue of mammalian SIRT1) in vitro and three of them showed dose dependent inhibition of Sir 2. The docking results suggested that the benzene ring of 1,2,3,4-tetrahydroquinazolin ring system of these molecules occupied the deep hydrophobic pocket of the protein and one of the NH along with the sulfonyl group participated in strong H-bonding interaction with the amino acid residues.     

Prevalence of methylenetetrahydrofolate reductase 677 C-T polymorphism among mothers of Down syndrome children

INTRODUCTION:

The relationship between chromosomal non-disjunction leading to aneuploidy and folate metabolism has drawn attention in the recent years. In this study, we examined the polymorphism in the gene encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR), namely, 677 C-T in women having Down syndrome (DS) children.

MATERIALS AND METHODS:

The prevalence of these variant genotypes (MTHFR 677 C-T polymorphism) in women having DS children (case mothers) (n = 110) was compared with controls (n = 111) from Punjab. Genotyping was done using the polymerase chain reaction method followed by restriction fragment length polymorphism.

RESULTS:

In the present study, 1.8% of case mothers had TT genotype while none of the control mothers showed this genotype. T allele frequency among cases was 0.13 and 0.11 in controls. The Chi-square value showed a non-significant difference between cases and controls.

CONCLUSION:

No association has been observed between 677 C-T polymorphism and risk of non-disjunction in case mothers. Detection of polymorphisms in more genes of folate pathway is required to find out the exact cause of non-disjunction.     

Genomic instability and enhanced radiosensitivity in Hsp70.1- and Hsp70.3-deficient mice

Heat shock proteins (HSPs) are highly conserved among all organisms from prokaryotes to eukaryotes. In mice, the HSP genes Hsp70.1 and Hsp70.3 are induced by both endogenous and exogenous stressors, such as heat and toxicants. In order to determine whether such proteins specifically influence genomic instability, mice deficient for Hsp70.1 and Hsp70.3 (Hsp70.1/3(-/-) mice) were generated by gene targeting. Mouse embryonic fibroblasts (MEFs) prepared from Hsp70.1/3(-/-) mice did not synthesize Hsp70.1 or Hsp70.3 after heat-induced stress. While the Hsp70.1/3(-/-) mutant mice were fertile, their cells displayed genomic instability that was enhanced by heat treatment. Cells from Hsp70.1/3(-/-) mice also display a higher frequency of chromosome end-to-end associations than do control Hsp70.1/3(+/+) cells. To determine whether observed genomic instability was related to defective chromosome repair, Hsp70.1/3(-/-) and Hsp70.1/3(+/+) fibroblasts were treated with ionizing radiation (IR) alone or heat and IR. Exposure to IR led to more residual chromosome aberrations, radioresistant DNA synthesis (a hallmark of genomic instability), increased cell killing, and enhanced IR-induced oncogenic transformation in Hsp70.1/3(-/-) cells. Heat treatment prior to IR exposure enhanced cell killing, S-phase-specific chromosome damage, and the frequency of transformants in Hsp70.1/3(-/-) cells in comparison to Hsp70.1/3(+/+) cells. Both in vivo and in vitro studies demonstrate for the first time that Hsp70.1 and Hsp70.3 have an essential role in maintaining genomic stability under stress conditions.     

Dissecting the neutralizing antibody specificities of broadly neutralizing sera from human immunodeficiency virus type 1-infected donors

Attempts to elicit broadly neutralizing antibody responses by human immunodeficiency virus type 1 (HIV-1) vaccine antigens have been met with limited success. To better understand the requirements for cross-neutralization of HIV-1, we have characterized the neutralizing antibody specificities present in the sera of three asymptomatic individuals exhibiting broad neutralization. Two individuals were infected with clade B viruses and the third with a clade A virus. The broadly neutralizing activity could be exclusively assigned to the protein A-reactive immunoglobulin G (IgG) fraction of all three donor sera. Neutralization inhibition assays performed with a panel of linear peptides corresponding to the third hypervariable (V3) loop of gp120 failed to inhibit serum neutralization of a panel of HIV-1 viruses. The sera also failed to neutralize chimeric simian immunodeficiency virus (SIV) and HIV-2 viruses displaying highly conserved gp41-neutralizing epitopes, suggesting that antibodies directed against these epitopes likely do not account for the broad neutralizing activity observed. Polyclonal IgG was fractionated on recombinant monomeric clade B gp120, and the neutralization capacities of the gp120-depleted samples were compared to that of the original polyclonal IgG. We found that the gp120-binding antibody population mediated neutralization of some isolates, but not all. Overall, the data suggest that broad neutralization results from more than one specificity in the sera but that the number of these specificities is likely small. The most likely epitope recognized by the monomeric gp120 binding neutralizing fraction is the CD4 binding site, although other epitopes, such as the glycan shield, cannot be excluded.     

MIF-1 and its peptidomimetic analogs attenuate haloperidol-induced vacuous chewing movements and modulate apomorphine-induced rotational behavior in 6-hydroxydopamine-lesioned rats

Two melanocyte-stimulating hormone release inhibiting factor-1 (MIF-1) also known as L-prolyl-L-leucyl-glycinamide (PLG) peptidomimetic analogs, 3(R)-[[[2(S)-pyrrolidinyl]carbonyl]-amino]-3-(butyl)-2-oxo-1-pyrrolidineacetamide trifluoroacetate (A) and 3(R)-[[[2(S)-pyrrolidinyl]carbonyl]amino]-3-(benzyl)-2-oxo-1-pyrrolidineacetamide trifluoroacetate (B), were evaluated for their ability to modulate dopaminergic activity by measuring apomorphine-induced rotations in 6-hydroxydopamine (6-OHDA)-lesioned rats, and haloperidol (HP)-induced vacuous chewing movements (VCMs) in rats; animal models of Parkinson's disease (PD) and human tardive dyskinesia (TD), respectively. In the 6-OHDA model, both analogs were found to potentiate the contralateral rotational behavior induced by apomorphine dose-dependently and with approximately the same potency. Furthermore, each analog was able to significantly attenuate HP-induced VCMs with almost equal efficacy. The potency and efficacy of these analogs were significantly greater than their parent compound, PLG. These results suggest that both analogs can modulate dopaminergic activity in vivo, likely by the same mechanisms recruited by PLG previously reported.     

Antisense expression of a gene encoding a calcium-binding protein in transgenic tobacco leads to altered morphology and enhanced chlorophyll

Entamoeba histolytica contains a novel calcium-binding protein like calmodulin, which was discovered earlier, and we have reported the presence of its homologue(s) and a dependent protein kinase in plants. To understand the functions of these in plants, a cDNA encoding a calcium-binding protein isolated from Entamoeba histolytica (EhCaBP) was cloned into vector pBI121 in antisense orientation and transgenic tobacco plants were raised. These plants showed variation in several phenotypic characters, of which two distinct features, more greenness and leaf thickness, were inherited in subsequent generations. The increase in the level of total chlorophyll in different plants ranged from 60% to 70%. There was no major change in chloroplast structure and in the protein level of D1, D2, LHCP and RuBP carboxylase. These morphological changes were not seen in antisense calmodulin transgenic tobacco plants, nor was the calmodulin level altered in EhCaBP antisense plants. The results of this paper have been granted US Patent No. 6,791,009.