Publications by authors named "Keshav Sharma"

Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high-resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. Immunoglobulin A-positive (IgA) PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection.

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In this work, we unveil a novel synthesis of bench stable Ni (II) complexes supported by tetradentate Schiff-base ligands and the complexes were devoid of any phosphine or phosphine-based ligand. These Ni-complexes were successfully applied for the dehydrogenation of secondary alcohols for ketone and ketazine syntheses. Secondary alcohols with different functional groups were well tolerated during catalytic cycle.

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Article Synopsis
  • Surface-enhanced Raman spectroscopy (SERS) is a sensitive technique for detecting tiny amounts of substances, but the reliability of results is affected by the properties of the substrates used.
  • This study introduces a new, cost-effective nanocomposite made of silver nanoparticles and porous magnesium oxide, which enhances SERS performance due to its unique structure that creates more active sites for adsorption.
  • The nanocomposite effectively detects a variety of environmental pollutants at low concentrations with high stability and reproducibility, offering a promising tool for monitoring contaminants in different fields.
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Unlabelled: Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. IgA PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection.

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We present a Raman spectroscopy study of the vibrational properties of free-base meso-tetra(4-pyridyl) porphyrin polycrystals under various temperature and hydrostatic pressure conditions. The combination of experimental results and Density Functional Theory (DFT) calculations allows us to assign most of the observed Raman bands. The modifications in the Raman spectra when excited with 488 nm and 532 nm laser lights indicate that a resonance effect in the Qy band is taking place.

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This work describes a new well-defined, air-stable, phosphine free palladium(II) [Pd(L)Cl] (1) catalyst. This catalyst was utilized for -alkylation of amines and indole synthesis where HO was found to be the by-product. A broad range of aromatic amines were alkylated using this homogeneous catalyst with a catalyst loading of 0.

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Vedolizumab (VDZ) is a first-line treatment in ulcerative colitis (UC) that targets the α4β7- mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) axis. To determine the mechanisms of action of VDZ, we examined five distinct cohorts of patients with UC. A decrease in naïve B and T cells in the intestines and gut-homing (β7) plasmablasts in circulation of VDZ-treated patients suggested that VDZ targets gut-associated lymphoid tissue (GALT).

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Skin is now emerging as a complex realm of three chief systems viz. immune system, nervous system, and endocrine system. The cells involved in their intricate crosstalk, namely native skin cells, intra-cutaneous immune cells and cutaneous sensory neurons have diverse origin and distinct functions.

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Most rust resistance genes thus far isolated from wheat have a very limited number of functional alleles. Here, we report the isolation of most of the alleles at wheat stem rust resistance gene locus SR9. The seven previously reported resistance alleles (Sr9a, Sr9b, Sr9d, Sr9e, Sr9f, Sr9g, and Sr9h) are characterised using a synergistic strategy.

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Article Synopsis
  • Drug resistance in leprosy is increasing, leading to treatment failure and the risk of spreading resistant strains of Mycobacterium leprae, prompting this study on drug resistance patterns in India.
  • Out of 136 leprosy patients analyzed, 16.9% had mutations indicating drug resistance, with the highest resistance found for ofloxacin (12.5%), and lower resistance rates for dapsone and rifampicin (2.2% each).
  • The findings emphasize the need for better treatment strategies, increased use of effective drugs, and improved surveillance systems for monitoring drug resistance in areas with high leprosy prevalence.
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Targeting the α4β7-MAdCAM-1 axis with vedolizumab (VDZ) is a front-line therapeutic paradigm in ulcerative colitis (UC). However, mechanism(s) of action (MOA) of VDZ remain relatively undefined. Here, we examined three distinct cohorts of patients with UC (n=83, n=60, and n=21), to determine the effect of VDZ on the mucosal and peripheral immune system.

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Article Synopsis
  • - Psoriasis is a chronic inflammatory skin disorder with both genetic and environmental factors, leading to symptoms like skin lesions and potential joint issues, characterized by periods of flare-ups and quiet times.
  • - The underlying causes involve abnormal immune responses, particularly by T cells, and are driven by specific cytokines, which have been identified through recent genetic and immunological research.
  • - New targeted therapies focusing on specific cytokines have improved treatment outcomes for severe psoriasis and related joint problems, paving the way for more personalized medicine and better management of associated health issues.
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Telomeric DNA challenges the replisome and requires TRF1 for efficient duplication. TRF1 recruits the BLM helicase, but BLM loss does not explain the extensive telomere fragility, ATR signaling, and sister telomere associations (STAs) induced by TRF1 deletion. Here, we document that Helix2 of the TRFH domain and Helix1 of the Myb domain of TRF1 are required for efficient telomere replication.

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Two conserved Glycine max (soybean) mitogen activated protein kinase 3 (MAPK3) paralogs function in defense to the parasitic soybean cyst nematode Heterodera glycines. Gene Ontology analyses of RNA seq data obtained from MAPK3-1-overexpressing (OE) and MAPK3-2-OE roots compared to their control, as well as MAPK3-1-RNA interference (RNAi) and MAPK3-2-RNAi compared to their control, hierarchically orders the induced and suppressed genes, strengthening the hypothesis that their heterologous expression in Gossypium hirsutum (upland cotton) would impair parasitism by the root knot nematode (RKN) Meloidogyne incognita. MAPK3-1 expression (E) in G.

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Expression of the central circadian oscillator components CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), TIMING OF CAB1 (TOC1), GIGANTEA (GI), and CONSTANS (CO) occurs in Glycine max root cells (syncytia) parasitized by the nematode Heterodera glycines while undergoing resistance, indicating a defense role. GmCCA1-1 relative transcript abundance (RTA) in roots experiencing overexpression (OE) or RNA interference (RNAi) is characterized by rhythmic oscillations, compared to a ribosomal protein gene (GmRPS21) control. A GmCCA1-1 RTA change, advancing by 12 h, exists in H.

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Article Synopsis
  • The study examines how root cells transform into syncytia due to pathogenic nematode activity, isolating these cells using laser microdissection for analysis.
  • Microarray data reveals that certain genes involved in the common symbiosis pathway also play a role in defense against parasitism, suggesting overlapping functions between symbiosis and defense mechanisms.
  • Manipulating the expression of specific genes through transgenic overexpression or RNA interference demonstrates that these genes have a dual role in defending against nematode parasitism, altering gene expression patterns in response to different genetic alterations.
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Double-strand break (DSB) repair relies on DNA damage response (DDR) factors including BRCA1, BRCA2, and RAD51, which promote homology-directed repair (HDR); 53BP1, which affects single-stranded DNA formation; and proteins that mediate end-joining. Here we show that the CRL4/DDB1/WDR70 complex (CRL4) controls the expression of DDR factors. Auxin-mediated degradation of WDR70 led to reduced expression of BRCA1, BRCA2, RAD51, and other HDR factors; 53BP1 and its downstream effectors; and other DDR factors.

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B cells, which are critical for intestinal homeostasis, remain understudied in ulcerative colitis (UC). In this study, we recruited three cohorts of patients with UC (primary cohort, n = 145; validation cohort 1, n = 664; and validation cohort 2, n = 143) to comprehensively define the landscape of B cells during UC-associated intestinal inflammation. Using single-cell RNA sequencing, single-cell IgH gene sequencing and protein-level validation, we mapped the compositional, transcriptional and clonotypic landscape of mucosal and circulating B cells.

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Erythema nodosum leprosum (ENL), also known as type 2 reaction (T2R) is an immune complex mediated (type III hypersensitivity) reactional state encountered in patients with borderline lepromatous and lepromatous leprosy (BL and LL) either before, during, or after the institution of anti-leprosy treatment (ALT). The consequences of ENL may be serious, leading to permanent nerve damage and deformities, constituting a major cause of leprosy-related morbidity. The incidence of ENL is increasing with the increasing number of multibacillary cases.

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