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The human gastrointestinal tract (GIT) contains a dynamic and diverse collection of bacteria, archaea, and fungi termed the "gut microbiome." The gut microbiome has a major impact on the host during homeostasis and disease. The connection between both the host and the microbiome is complex, although its manipulation may assist prevent or treating a multitude of morbidities. These microorganisms play a critical role in the host's energy metabolism and homeostasis. According to new research, the microbes in the gastrointestinal tract play a substantial role in host health, and alterations in its composition and function might lead to the emergence of metabolic disorders like non-alcoholic fatty liver disease (NAFLD). The resilience of the GIT microbial ecology and its tolerance to perturbation are robust but not ideal. Several factors may disrupt the GIT microbiome's homeostasis leading to dysbiosis, characterized by an imbalanced equilibrium and perturbations in gut homeostasis. Irritable bowel disease (IBD), malnutrition, and metabolic disorders, such as NAFLD, have been associated with the dysbiotic gut microbiome. Recent evidence suggests that utilizing medications, prebiotics, probiotics, and fecal microbiota transplantation (FMT) to manipulate the microbiome could be a viable method for treating NAFLD.

Vibrio choleraeO1 and O139 isolates deploy cholera toxin (CT) and toxin-coregulated pilus (TCP) to cause the diarrhoeal disease cholera. ThectxABandtcpAgenes encoding CT and TCP are part of two acquired genetic elements, the CTX phage andVibriopathogenicity island-1 (VPI-1), respectively. ToxR and ToxT proteins are the key regulators of virulence genes ofV. choleraeO1 and O139.V. choleraeisolates belonging to serogroups other than O1/O139, called non-O1/non-O139, are usually devoid of virulence-related elements and are non-pathogenic. Here, we have analysed the available whole genome sequence of an environmental toxigenicV. choleraenon-O1/non-O139 strain, VCE232, carrying the CTX phage and VPI-1. Extensive bioinformatics and phylogenetic analyses indicated high similarity of the VCE232 genome sequence with the genome ofV. choleraeO1 strains, including organization of the VPI-1 locus,ctxAB, tcpAandtoxTgenes, and promoters. We established that the VCE232 strain produces an optimal amount of CT at 30 °C under AKI conditions. To investigate the role of ToxT and ToxR in the regulation of virulence factors, we constructed ΔtoxT, ΔtoxRand ΔtoxTΔtoxRdeletion mutants of VCE232. Extensive genetic analyses of these mutants indicated that thetoxTandtoxRgenes of VCE232 are crucial for CT and TCP production. However, unlike O1 isolates, the presence of eithertoxTortoxRgene is sufficient for optimal CT production in VCE232. In addition, the VCE232 ΔtoxRmutant showed differential regulation of the major outer membrane proteins, OmpT and OmpU. This is the first attempt to explore the regulation of expression of major virulence genes and regulators in an environmental toxigenicV. choleraenon-O1/non-O139 strain.

Helicobacter pylori is a ubiquitous bacterium and contributes significantly to the burden of chronic gastritis, peptic ulcers, and gastric cancer across the world. Adaptive phenotypes and virulence factors in H. pylori are heterogeneous and dynamic. However, limited information is available about the molecular nature of antimicrobial resistance phenotypes and virulence factors of H. pylori strains circulating in India. In the present study, we analyzed the whole genome sequences of 143 H. pylori strains, of which 32 are isolated from two different regions (eastern and southern) of India. Genomic repertoires of individual strains show distinct region-specific signatures. We observed lower resistance phenotypes and genotypes in the East Indian (Kolkata) H. pylori isolates against amoxicillin and furazolidone antibiotics, whereas higher resistance phenotypes to metronidazole and clarithromycin. Also, at molecular level, a greater number of AMR genes were observed in the east Indian H. pylori isolates as compared to the southern Indian isolates. From our findings, we suggest that metronidazole and clarithromycin antibiotics should be used judicially in the eastern India. However, no horizontally acquired antimicrobial resistance gene was observed in the current H. pylori strains. The comparative genome analysis shows that the number of genes involved in virulence, disease and resistance of H. pylori isolated from two different regions of India is significantly different. Single-nucleotide polymorphisms (SNPs) based phylogenetic analysis distinguished H. pylori strains into different clades according to their geographical locations. Conditionally beneficial functions including antibiotic resistance phenotypes that are linked with faster evolution rates in the Indian isolates.

Nanoparticles show the multidisciplinary versatile utility and are gaining the prime place in various fields, such as medicine, electronics, pharmaceuticals, electrical designing, cosmetics, food industries, and agriculture, due to their small size and large surface to volume ratio. Biogenic or green synthesis methods are environmentally friendly, economically feasible, rapid, free of organic solvents, and reliable over conventional methods. Plant extracts are of incredible potential in the biosynthesis of metal nanoparticles owing to their bountiful availability, stabilizing, and reducing ability. In the present study, the aqueous leaf extract of