Biology subjects

Sharma, K.

Publications and source records attributed to Sharma, K..

100 records · Page 6Linked to original sources

bioRxiv2020

Systematic hormone-metabolite network provides insights of high salinity tolerance in Pongamia pinnata (L.) pierre

Salinity stress results significant losses in plant productivity, and loss of cultivable lands. Although Pongamia pinnata is reported to be a salt tolerant semiarid tree crop, the adaptive mechanisms to saline environment are elusive. The present investigation describes alterations in hormonal and metabolic responses in correlation with physiological and molecular variations in leaves and roots of Pongamia at sea salinity level (3% NaCl) for 8 days. At physiological level, salinity induced adjustments in plant morphology, leaf gas exchange and ion accumulation patterns were observed. Our study also revealed that phytohormones including JAs and ABA play crucial role in promoting the salt adaptive strategies such as apoplasmic Na+ sequestration and cell wall lignification in leaves and roots of Pongamia. Correlation studies demonstrated that hormones including ABA, JAs and SA showed a positive interaction with selective compatible metabolites (sugars, polyols and organic acids) to aid in maintaining osmotic balance and conferring salt tolerance to Pongamia. At the molecular level, our data showed that differential expression of transporter genes as well as antioxidant genes regulate the ionic and ROS homeostasis in Pongamia. Collectively, these results shed new insights on an integrated physiological, structural, molecular and metabolic adaptations conferring salinity tolerance to Pongamia. High lightOur data, for the first time, provide new insights for an integrated molecular and metabolic adaptation conferring salinity tolerance in Pongamia. The present investigation describes alterations in hormonal and metabolic responses in correlation with physiological and molecular variations in Pongamia at sea salinity level (3% NaCl) for 8 days.

plant biology↗

bioRxiv2020

A lung-on-chip infection model reveals protective and permissive roles of alveolar epithelial cells in tuberculosis

Mycobacterium tuberculosis (Mtb) makes first contact with a host in the alveolar space, an interaction largely inaccessible to experimental observation. We establish a lung-on-chip model for early tuberculosis and use time-lapse imaging to reveal the dynamics of host-Mtb interactions at an air-liquid interface with a spatiotemporal resolution unattainable in animal models. By reconstituting host physiology in a modular manner, we probe the role of pulmonary surfactant secreted by alveolar epithelial cells (AECs) in early infection. This is difficult to study directly in animal models, as surfactant-deficient animals are either non-viable or develop acute lung pathologies. We demonstrate that surfactant deficiency results in rapid and uncontrolled Mtb growth in both macrophages and AECs. In contrast, under normal surfactant levels, a significant fraction of intracellular bacteria are non-growing. The surfactant-deficient phenotype is rescued by exogenous addition of surfactant replacement formulations, which have no effect on bacterial viability in the absence of host cells. Surfactant partially removes virulence-associated lipids and proteins 1,2 from the bacterial cell surface and consistent with this mechanism of action, we show that attenuation of bacteria lacking the virulence-associated ESX-1 secretion system is independent of surfactant levels. These findings may partly explain why individuals with compromised surfactant function, such as smokers and elderly persons, are at increased risk of developing active tuberculosis.

microbiology↗

bioRxiv2019

A Multimodal and Integrated Approach to Interrogate Human Kidney Biopsies with Rigor and Reproducibility: The Kidney Precision Medicine Project

Comprehensive and spatially mapped molecular atlases of organs at a cellular level are a critical resource to gain insights into pathogenic mechanisms and personalized therapies for diseases. The Kidney Precision Medicine Project (KPMP) is an endeavor to generate 3-dimensional (3D) molecular atlases of healthy and diseased kidney biopsies using multiple state-of-the-art OMICS and imaging technologies across several institutions. Obtaining rigorous and reproducible results from disparate methods and at different sites to interrogate biomolecules at a single cell level or in 3D space is a significant challenge that can be a futile exercise if not well controlled. We describe a "follow the tissue" pipeline for generating a reliable and authentic single cell/region 3D molecular atlas of human adult kidney. Our approach emphasizes quality assurance, quality control, validation and harmonization across different OMICS and imaging technologies from sample procurement, processing, storage, shipping to data generation, analysis and sharing. We established benchmarks for quality control, rigor, reproducibility and feasibility across multiple technologies through a pilot experiment using common source tissue that was processed and analyzed at different institutions and different technologies. A peer review system was established to critically review quality control measures and the reproducibility of data generated by each technology before being approved to interrogate clinical biopsy specimens. The process established economizes the use of valuable biopsy tissue for multi-OMICS and imaging analysis with stringent quality control to ensure rigor and reproducibility of results and serves as a model for precision medicine projects across laboratories, institutions and consortia.

scientific communication and education↗

bioRxiv2019

Interplay of bacterial membrane vesicle and host lipid physicochemical parameters during host-bacterial membrane vesicle interaction

Bacterial membrane vesicles (MVs) facilitate long-distance delivery of virulence factors crucial for pathogenicity. The entry and trafficking mechanisms of virulence factors inside host cells are recently emerging, however, if bacterial MVs can fuse and modulate the physicochemical properties of the host lipid membrane and membrane lipid parameter for fusion remains unknown. Here we reconstitute the interaction of bacterial MV with host cell lipid membranes and quantitatively show that bacterial MV interaction increases the fluidity, dipole potential, and Compressibility of a biologically relevant multi-component host membrane upon fusion. The presence of cylindrical lipids such as phosphatidylcholine and a moderate acyl chain length of C16 helps the MV interaction. While significant binding of bacterial MVs to the raft-like lipid membranes with phase-separated regions of the membrane was observed, however, MVs prefer binding to the liquid-disordered regions of the membrane. Further, the elevated levels of cholesterol tend to hinder the interaction of bacterial MVs as evident from the favorable excess Gibbs free energy of mixing of bacterial MVs with host lipid membranes. The findings provide new insights that might have implications for the regulation of host machinery by bacterial pathogens through the manipulation of host membrane properties.

biochemistry↗

bioRxiv2019

CoRNeA: A pipeline to decrypt the protein-protein interaction from amino acid sequence information

Computational methods have been devised in the past to predict the interface residues using amino acid sequence information but have been majorly applied to predict for prokaryotic protein complexes. Since the composition and rate of evolution of the primary sequence are different between prokaryotes and eukaryotes, it is important to develop a method specifically for eukaryotic complexes. Here we report a new hybrid pipeline for the prediction of protein-protein interaction interfaces from the amino acid sequence information alone based on the framework of Co-evolution, machine learning (Random forest) and Network Analysis named CoRNeA trained specifically on eukaryotic protein complexes. We incorporate the intra contact information of the individual proteins to eliminate false positives from the predictions as the amino acid sequence also holds information for its own folding along with the interface propensities. Our prediction on various case studies shows that CoRNeA can successfully identify minimal interacting regions of two partner proteins with higher precision and recall.

bioinformatics↗

bioRxiv2019

Persistent anti-heart autoimmunity causes cardiomyocyte damage in chronic heart failure.

Although clinicians and researchers have long appreciated the detrimental effects of excessive acute inflammation after myocardial infarction (MI), less is known about the role of the adaptive immune system in MI complications including heart failure. Yet, abundant cardiac self-antigens released from necrotic cardiomyocytes in a highly inflammatory environment are likely to overwhelm peripheral mechanisms of immunological self-tolerance and adaptive auto-reactivity against the heart may cause ongoing tissue destruction and exacerbate progression to chronic heart failure (CHF). Here, we confirm that the adaptive immune system is indeed persistently active in CHF due to ischemic heart disease triggered by MI in rats. Heart draining mediastinal lymph nodes contain active secondary follicles with mature class-switched IgG2a positive cells, and mature anti-heart auto-antibodies binding to cardiac epitopes are still present in serum as late as 16 weeks after MI. When applied to healthy cardiomyocytes in vitro, humoral factors present in CHF serum promoted apoptosis, cytotoxicity and signs of hypertrophy. These findings directly implicate post-MI autoimmunity as an integral feature of CHF progression, constituting a roadblock to effective regeneration and a promising target for therapeutic intervention.

immunology↗

bioRxiv2019

Doubled haploid based parental lines are most suitable in predicting heterosis using microsatellites and in development of highly heterotic F1 hybrids in Brassica oleracea

In Brassica oleracea, heterosis is one of the most efficient tools giving impetus to hybrid vegetable industry. In this context, we presented the first report on identifying superior heterotic crosses for yield and commercial traits in cauliflower involving cytoplasmic male sterile (CMS) and doubled haploid (DH) lines as parents. We studied the suitability of SSR and EST-SSRs based genetic distance (GD) and morphological markers based phenotypic distance (PD) in prediction of heterosis when DH based genotypes are used as parents in developing F1 hybrids. Overall 120 F1 hybrids derived from twenty Ogura cybrid CMS lines and six DH based testers were evaluated for 16 phenotypic traits along with their 26 parental lines and 4 commercial standard checks, in 10 x 15 alpha lattice design. The genomic SSR and EST-SSRs based genetic structure analysis grouped 26 parental lines into 4 distinct clusters. The CMS lines Ogu118-6A, Ogu33A, Ogu34-1A were good general combiner for developing short duration hybrids. The SCA effects were significantly associated with heterosis suggesting non-additive gene effects for heterotic response of hybrids. Less than unity value of {sigma}2A/D coupled with {sigma}2gca/{sigma}2scaindicated the predominance of non-additive gene action in the expression of studied traits. The genetic distance estimates among 26 parents ranged from 0.44 to 0.98 and were significantly associated with heterosis for important commercial traits, suggesting the utility of microsatellite based genetic distance in prediction of heterosis in B. oleracea.

plant biology↗

bioRxiv2018

The Cuon Enigma: Genome survey and comparative genomics of the endangered Dhole (Cuon alpinus)

The Asiatic wild dog is an endangered monophyletic canid restricted to Asia; facing threats from habitat fragmentation and other anthropogenic factors. Dholes have unique adaptations as compared to other wolf-like canids for large litter size (larger number of mammae) and hypercarnivory making it evolutionarily notable. Over evolutionary time, dhole and the subsequent divergent wild canids have lost coat patterns found in African wild dog. Here we report the first high coverage genome survey of Asiatic wild dog and mapped it with African wild dog, dingo and domestic dog to assess the structural variants. We generated a total of 124.8 Gb data from 416140921 raw read pairs and retained 398659457 reads with 52X coverage and mapped 99.16% of the clean reads to the three reference genomes. We identified ~13553269 SNVs, ~2858184 InDels, ~41000 SVs, ~1854109 SSRs and about 1000 CNVs. We compared the annotated genome of dingo and domestic dog with dhole genome sequence to understand the role of genes responsible in pelage pattern, dentition and mammary glands. Positively selected genes for these phenotypes were looked for SNP variants and top ranked genes for coat pattern, dentition and mammary glands were found to play a role in signalling and developmental pathways. Mitochondrial genome assembly predicted 35 genes, 11 CDS and 24 tRNA. This genome information will help in understanding the divergence of two monophlyletic canids, Cuon and Lycaon, and the evolutionary adaptations of dholes with respect to other canids.

genomics↗

bioRxiv2018

Mitogen activated protein kinases function as a cohort during a plant defense response

Mitogen activated protein kinases (MAPKs) play important signal transduction roles. However, little is known regarding whether MAPKs influence the gene expression of other family members and the relationship that expression has to a biological process. Transcriptomic studies have identified MAPK gene expression occurring within root cells undergoing a defense response to a pathogenic event in the allotetraploid Glycine max. Furthermore, functional analyses are presented for its 32 MAPKs revealing 9 of the 32 MAPKs have a defense role, including homologs of Arabidopsis thaliana MAPK (MPK) MPK2, MPK3, MPK4, MPK5, MPK6, MPK13, MPK16 and MPK20. Defense signal transduction processes occurring through pathogen activated molecular pattern (PAMP) triggered immunity (PTI) and effector triggered immunity (ETI) have been determined in relation to these MAPKs. PTI has been analyzed by examining BOTRYTIS INDUCED KINASE1 (BIK1), ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and LESION SIMULATING DISEASE1 (LSD1). ETI has been analyzed by examining the role of the bacterial effector protein harpin and the downstream cell membrane receptor NON-RACE SPECIFIC DISEASE RESISTANCE1 (NDR1). Experiments have identified 5 different types of gene expression relating to MAPK expression. The MAPKs are shown to influence PTI and ETI gene expression and a panel of proven defense genes including an ABC-G type transporter, 20S membrane fusion particle components, glycoside biosynthesis, carbon metabolism, hemicellulose modification, transcription and PATHOGENESIS RELATED 1 (PR1). The experiments show MAPKs broadly influence the expression of other defense MAPKs, including the co-regulation of parologous MAPKs and reveal its relationship to proven defense genes.

molecular biology↗

bioRxiv2018

Formulation, Evaluation and Antibacterial Efficiency of water-based herbal Hand Sanitizer Gel

Hands are the primary mode of transmission of microbes and infections. Hand-washing is critical in food production, food service and also important in healthcare setting, homes and day care preparations. The present research was aimed to evaluate the antibacterial efficacy of various herbal oils such as Cinnamon oil, Eucalyptus oil, menthol oil and lavender oil and found that cinnamon oil showed better antibacterial activity. Also the research was carried out to formulate and evaluate the poly herbal Hand wash gel containing Azadirachta indica, Ocimum sanctum and Citrus limon extracts. The anti-microbial activity of the formulated herbal hand wash gel was tested against Escherichia coli, Staphylococcus aureus and Salmonella by spread plate techniques and the results obtained were compared with commercial antibacterial standards. Also the efficiency was checked by using the hand wash gel on volunteers. The results from the present work suggest and support the incorporation and utilization of herbs in the formulations to give better effect.

microbiology↗