Showing papers by "Chaitanya G. Joshi published in 2022"

Defective ORF8 dimerization in SARS-CoV-2 delta variant leads to a better adaptive immune response due to abrogation of ORF8-MHC1 interaction

Abstract: In India, during the second wave of the COVID-19 pandemic, the breakthrough infections were mainly caused by the SARS-COV-2 delta variant (B.1.617.2). It was reported that, among majority of the infections due to the delta variant, only 9.8% percent cases required hospitalization, whereas only 0.4% fatality was observed. Sudden dropdown in COVID-19 infections cases were observed within a short timeframe, suggesting better host adaptation with evolved delta variant. Downregulation of host immune response against SARS-CoV-2 by ORF8 induced MHC-I degradation has been reported earlier. The Delta variant carried mutations (deletion) at Asp119 and Phe120 amino acids which are critical for ORF8 dimerization. The deletions of amino acids Asp119 and Phe120 in ORF8 of delta variant resulted in structural instability of ORF8 dimer caused by disruption of hydrogen bonds and salt bridges as revealed by structural analysis and MD simulation studies. Further, flexible docking of wild type and mutant ORF8 dimer revealed reduced interaction of mutant ORF8 dimer with MHC-I as compared to wild-type ORF8 dimer with MHC-1, thus implicating its possible role in MHC-I expression and host immune response against SARS-CoV-2. We thus propose that mutant ORF8 of SARS-CoV-2 delta variant may not be hindering the MHC-I expression thereby resulting in a better immune response against the SARS-CoV-2 delta variant, which partly explains the possible reason for sudden drop of SARS-CoV-2 infection rate in the second wave of SARS-CoV-2 predominated by delta variant in India.

Evaluation of immune evasion in SARS-CoV-2 Delta and Omicron variants

Abstract: Emerging SARS-CoV-2 variants with higher transmissibility and immune escape remain a persistent threat across the globe. This is evident from the recent outbreaks of the Delta (B.1.617.2) and Omicron variants. These variants have originated from different continents and spread across the globe. In this study, we explored the genomic and structural basis of these variants for their lineage defining mutations of the spike protein through computational analysis, protein modeling, and molecular dynamic (MD) simulations. We further experimentally validated the importance of these deletion mutants for their immune escape using a pseudovirus-based neutralization assay, and an antibody (4A8) that binds directly to the spike protein's NTD. Delta variant with the deletion and mutations in the NTD revealed a better rigidity and reduced flexibility as compared to the wild-type spike protein (Wuhan isolate). Furthermore, computational studies of 4A8 monoclonal antibody (mAb) revealed a reduced binding of Delta variant compared to the wild-type strain. Similarly, the MD simulation data and virus neutralization assays revealed that the Omicron also exhibits immune escape, as antigenic beta-sheets appear to be disrupted. The results of the present study demonstrate the higher possibility of immune escape and thereby achieved better fitness advantages by the Delta and Omicron variants, which warrants further demonstrations through experimental evidences. Our study, based on in-silico computational modelling, simulations, and pseudovirus-based neutralization assay, highlighted and identified the probable mechanism through which the Delta and Omicron variants are more pathogenically evolved with higher transmissibility as compared to the wild-type strain.

Kidney transcriptome response to salinity adaptation in Labeo rohita

Abstract: The increasing salinization of freshwater resources, owing to global warming, has caused concern to freshwater aquaculturists. In this regard, the present study is aimed at economically important freshwater fish, L. rohita (rohu) adapting to varying degrees of salinity concentrations. The RNA-seq analysis of kidney tissue samples of L. rohita maintained at 2, 4, 6, and 8 ppt salinity was performed, and differentially expressed genes involved in various pathways were studied. A total of 755, 834, 738, and 716 transcripts were downregulated and 660, 926, 576, and 908 transcripts were up-regulated in 2, 4, 6, and 8 ppt salinity treatment groups, respectively, with reference to the control. Gene ontology enrichment analysis categorized the differentially expressed genes into 69, 154, 92, and 157 numbers of biological processes with the p value < 0.05 for 2, 4, 6, and 8 ppt salinity groups, respectively, based on gene functions. The present study found 26 differentially expressed solute carrier family genes involved in ion transportation and glucose transportation which play a significant role in osmoregulation. In addition, the upregulation of inositol-3-phosphate synthase 1A (INO1) enzyme indicated the role of osmolytes in salinity acclimatization of L. rohita. Apart from this, the study has also found a significant number of genes involved in the pathways related to salinity adaptation including energy metabolism, calcium ion regulation, immune response, structural reorganization, and apoptosis. The kidney transcriptome analysis elucidates a step forward in understanding the osmoregulatory process in L. rohita and their adaptation to salinity changes.

Comparative analysis of two next generation sequencing platforms for analysis of antimicrobial resistance genes.

Abstract: The use of antibiotics in human medicine and livestock production has contributed to the widespread occurrence of Antimicrobial Resistance (AMR). Recognizing the relevance of AMR to human and livestock health, it is important to assess the occurrence of genetic determinants of resistance in medical, veterinary, and public health settings in order to understand risks of transmission and treatment failure. Advances in next-generation sequencing technologies have had a significant impact on research in microbial genetics and microbiome analyses. The aim of the present study was to compare the Illumina MiSeq and Ion Torrent S5 Plus sequencing platforms for the analysis of AMR genes in a veterinary/public health setting.All samples were processed in parallel for the two sequencing technologies, subsequently following a common bioinformatics workflow to define the occurrence and abundance of AMR gene sequences. The Comprehensive Antibiotic Resistance Database (CARD), QIAGEN Microbial Insight - Antimicrobial Resistance, Antimicrobial resistance database, and Comprehensive Antibiotic Resistance Database developed by CLC bio (CARD-CLC) databases were compared for analysis, with the most genes identified using CARD.Drawing on these results, we described an end-to-end workflow for the analysis of AMR genes a using advances in next-generation sequencing. No statistically significant differences were observed among any other genes except the tet-(40) gene between two sequencing platforms, which may be due to the short amplicon length.Irrespective of sequencing chemistry and platform used, comparative analysis of AMR genes and candidate host organism suggest that the Illumina MiSeq and Ion Torrent platforms performed almost equally. Regardless of sequencing platform, the results were closely comparable with minor differences.

Targeted Sequencing of Alzheimer’s Disease Genes in Gujarat Cohort

Abstract: Alzheimer’s Disease (AD) is the most common type of dementia affecting cognitive and behavioural functions. It’s a complex disease that results from the modest effect of gene interaction and environmental factors, as a result of which its exact pathogenesis is still unknown. In the present study, we have performed an association study of exonic regions of 94 genes with AD using the Haloplex target enrichment method and genotyping of 4 genes NOTCH4(rs367398), NEP(rs61760379), APOE (rs121918398), and ATP7B(rs1801243) using PCR RFLP technique. In this study, we screened 32 AD cases and 11 control samples. We have identified 19 variants assigned to 16 genes that were significantly associated with AD with a p-value < 0.05. However, no variants have passed multiple test corrections except NOTCH4/rs367398 genotyped using the PCR-RFLP approach. The functional enrichment analysis of the significant genes for the disease indicates that the genes are significantly involved in AD. Also, functional enrichment analysis for biological processes using ClueGo and network analysis using the STRING database indicated that the genes are directly and indirectly playing a role in AD pathogenesis. The eQTL analysis of the variants with GTEx dataset indicate that out of 19 variants ACHE/rs1799806 and NOTCH4/rs367398 variants is showing significant eQTL for the neighbouring genes for different brain regions and whole blood. Regardless, additional studies with a large cohort are required to establish the role and prevalence of these variants in the local population of Gujarat.

In-Depth Analysis of an Obligate Anaerobe Paraclostridium bifermentans Isolated from Uterus of Bubalus bubalis

Abstract: Simple Summary Non-specific uterine infections in bovine (uterine line inflammation) are a significant issue for the dairy industry. These infections are responsible for significant financial losses all over the world. Paraclostridium bifermentans is an obligate anaerobe, gram-positive rod-shaped bacteria belonging to the Clostridia class and the Peptostreptococcaceae family produces endospores. This bacterium has the ability to infiltrate bovine uterine endometrial epithelial cells and cause infection in the endometrium epithelial cells. Our study found that an examination of a buffalo uterus with yellowish purulent discharge reported the presence of pathogenic bacteria Paraclostridium bifermentans, where its genomic characterization, substrate utilization, and antibiotic susceptibility potentiality was studied. This discovery indicates the presence of virulence genes as well as pathogenic features. This is the first report of P. bifermentans from the bovine uterus environment. Abstract Chronic non-specific contamination of the reproductive tract in animals is a major issue during early postpartum, natural coitus, or artificial insemination. Uterine infection is one of the major concerns reducing fertility, production loss, and early culling of the animals. Therefore, the aim of this study was to identify any novel bacterium if present in the uterine environment of Bubalus bubalis causing infections. A strictly anaerobic bacterial strain designated as Paraclostridium bifermentans GBRC was isolated and characterized. Bacterium was found to be Gram positive moderate rod with motility. The optimum growth was observed at 40 ± 2 °C. The pathogenic characteristics of the GBRC strain, such as hemolysis, gelatin hydrolysis, and the production of volatile sulfur compounds, were similar to those seen in the epithelial layer invading pathogenic strains. Assembled genome size was 3.6 MB, with 78 contigs, and a G + C content of 28.10%. Furthermore, the whole genome sequence analysis confirmed the presence of genes encoding virulence factors and provided genomic insights on adaptation of the strain in the uterine environment. Based on the phenotypic and genetic differences with phylogenetic relatives, strain GBRC is proposed to represent a first reported species of the genus Paraclostridium with potential pathogenic character, from the buffalo uterine environment. This study analysis of the GBRC strain serves as a key reference point for the investigation of potential pathogenic strains that may cause endometritis and metritis in bovine.

RNASeq as a tool to understand dysregulation of potential biomarkers in HNSC

Abstract: With its rising fatality rates, oral cancer is one of the most concerning public health issues. To reduce disease-related mortality and morbidity, advancements in screening and detection are critical. Finding specific biomarkers is one of the most successful approaches for screening, diagnosing, and staging this dreadful disease. In this study differentially expressed genes associated with oral cancer were analyzed using RNASeq to find the potential biomarkers. Functional enrichment of upregulated genes found that 253 genes were present in the plasma membrane. Three clusters were formed using KMean Clustering from the PPI networks, and highly connected hub genes were identified from each cluster. Eventually, expression and survival analyses of hub genes were performed using The Cancer Genome Atlas (TCGA) database targeting Head and Neck Squamous Cell Carcinoma. Among those genes, expression levels of eight genes SLC2A1, ITGA6, LAMC2, COL1A2, COL1A1, TNC, THY1, and CD276 have significantly changed in Head and Neck Squamous cell carcinoma. There are reports that suggest these genes were significantly dysregulated in Oral Squamous cell carcinoma and can be explored further as potential biomarkers for margin clearance.

584. Genome-wide association studies of chicken caecal microbiota

Abstract: The enteric microbiota has a vital role in animal health and performance. Gut microbial community structure varies widely between individuals, suggesting that in addition to environmental factors there is also a host genetic component. The aim of this study was to identify heritable host (chicken) genetic variation associated with the microbial community structure in two broiler (meat-type chicken) breeds, the indigenous Indian Kadaknath and the commercial Cobb400, raised in western parts of India under the local prevailing husbandry conditions. We collected blood and caecal lumen contents from 300 birds from each breed. All birds were genotyped with the 600K AffymetrixÒ AxiomÒ HD array and the caecal lumen microbiota was defined using DNA-metabarcoding. Variant component estimates and genome-wide association studies were conducted. Using these datasets, we identified significant heritability estimates and genomic associations at genome-wide level (P<0.05 Bonferroni corrected) between host genetic variation and gut microbiome composition in both chicken breeds under investigation.

Surveillance and Molecular Characterization of SARS-CoV-2 Infection in Non-Human Hosts in Gujarat, India

Abstract: Since December 2019, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been spreading worldwide, triggering one of the most challenging pandemics in the human population. In light of the reporting of this virus in domestic and wild animals from several parts of the world, a systematic surveillance study was conceptualized to detect SARS-CoV-2 among species of veterinary importance. Nasal and/or rectal samples of 413 animals (dogs n= 195, cattle n = 64, horses n = 42, goats n = 41, buffaloes n = 39, sheep n = 19, cats n = 6, camels n = 6, and a monkey n = 1) were collected from different places in the Gujarat state of India. RNA was extracted from the samples and subjected to RT-qPCR-based quantification of the target sequences in viral nucleoprotein (N), spike (S), and ORF1ab genes. A total of 95 (23.79%) animals were found positive, comprised of n = 67 (34.35%) dogs, n= 15 (23.43%) cattle, and n = 13 (33.33%) buffaloes. Whole SARS-CoV-2 genome sequencing was done from one sample (ID-A4N, from a dog), where 32 mutations, including 29 single-nucleotide variations (SNV) and 2 deletions, were detected. Among them, nine mutations were located in the receptor binding domain of the spike (S) protein. The consequent changes in the amino acid sequence revealed T19R, G142D, E156-, F157-, A222V, L452R, T478K, D614G, and P681R mutations in the S protein and D63G, R203M, and D377Y in the N protein. The lineage assigned to this SARS-CoV-2 sequence is B.1.617.2. Thus, the present study highlights the transmission of SARS-CoV-2 infection from human to animals and suggests being watchful for zoonosis.

Rhizosphere microbiome analysis of healthy and infected cumin (Cuminum cyminum L.) varieties from Gujarat, India

Abstract: Cumin (Cuminum cyminum L.; Jeera) is a popular herbal seed spice used in culinary preparation in India. Gujarat and Rajasthan are the largest producer states of cumin seeds from India, while India is also the largest supplier and exporter of cumin across the globe. However, production of cumin is suffering from loss of crop production due to the plant pathogen infections, especially from Fusarium oxysporium sp. Rhizomicrobiome is the key modulator of plant health, revitalizing nutrients and disease response against plant pathogens. The secretion of different metabolites such as root exudates plays an important role in host plant rhizosphere microbial interactions influencing the plant health, growth and development, nutrient acquisition, and disease resistance. Therefore, in this research study, we have examined the microbial diversity from the healthy and fungal infected rhizosphere samples of the three different Gujarat Cumin (GC-2, GC-3, and GC-4) varieties using 16S ribosomal RNA (rRNA) gene sequencing on Ion Torrent S5 sequencing platform. The findings revealed the major dominant family represented by Bacillaceae, Solibacteraceae, Nostocaceae, Paenibacillaceae, Scytonemataceae, and Halothiobacillaceae, while at genera level of taxonomic abundance were represented by Bacillus, Candidatus Solibacter, Synechococcus, Nostoc, Anabaena, and Oscillatoria. The research findings should enhance our understanding of healthy and infected plant rhizosphere microbiome for better crop productivity, disease resistance and management of the crop varieties against plant pathogens.