Effects of Probiotics at the Interface of Metabolism and Immunity to Prevent Colorectal Cancer-Associated Gut Inflammation: A Systematic Network and Meta-Analysis With Molecular Docking Studies.

Background: Dysbiosis/imbalance in the gut microbial composition triggers chronic inflammation and promotes colorectal cancer (CRC). Modulation of the gut microbiome by the administration of probiotics is a promising strategy to reduce carcinogenic inflammation. However, the mechanism remains unclear. Methods: In this study, we presented a systematic network, meta-analysis, and molecular docking studies to determine the plausible mechanism of probiotic intervention in diminishing CRC-causing inflammations. Results: We selected 77 clinical, preclinical, in vitro, and in vivo articles (PRISMA guidelines) and identified 36 probiotics and 135 training genes connected to patients with CRC with probiotic application. The meta-analysis rationalizes the application of probiotics in the prevention and treatment of CRC. An association network is generated with 540 nodes and 1,423 edges. MCODE cluster analysis identifies 43 densely interconnected modules from the network. Gene ontology (GO) and pathway enrichment analysis of the top scoring and functionally significant modules reveal stress-induced metabolic pathways (JNK, MAPK), immunomodulatory pathways, intrinsic apoptotic pathways, and autophagy as contributors for CRC where probiotics could offer major benefits. Based on the enrichment analyses, 23 CRC-associated proteins and 7 probiotic-derived bacteriocins were selected for molecular docking studies. Results indicate that the key CRC-associated proteins (e.g., COX-2, CASP9, PI3K, and IL18R) significantly interact with the probiotic-derived bacteriocins (e.g., plantaricin JLA-9, lactococcin A, and lactococcin mmfii). Finally, a model for probiotic intervention to reduce CRC-associated inflammation has been proposed. Conclusion: Probiotics and/or probiotic-derived bacteriocins could directly interact with CRC-promoting COX2. They could modulate inflammatory NLRP3 and NFkB pathways to reduce CRC-associated inflammation. Probiotics could also activate autophagy and apoptosis by regulating PI3K/AKT and caspase pathways in CRC. In summary, the potential mechanisms of probiotic-mediated CRC prevention include multiple signaling cascades, yet pathways related to metabolism and immunity are the crucial ones.

SufB intein splicing in Mycobacterium tuberculosis is influenced by two remote conserved N-extein histidines.

Inteins are auto-processing domains that implement a multistep biochemical reaction termed protein splicing, marked by cleavage and formation of peptide bonds. They excise from a precursor protein, generating a functional protein via covalent bonding of flanking exteins. We report the kinetic study of splicing and cleavage reaction in [Fe-S] cluster assembly protein SufB from Mycobacterium tuberculosis (Mtu). Although it follows a canonical intein splicing pathway, distinct features are added by extein residues present in the active site. Sequence analysis identified two conserved histidines in the N-extein region; His-5 and His-38. Kinetic analyses of His-5Ala and His-38Ala SufB mutants exhibited significant reductions in splicing and cleavage rates relative to the SufB wildtype (WT) precursor protein. Structural analysis and molecular dynamics (MD) simulations suggested that Mtu SufB displays a unique mechanism where two remote histidines work concurrently to facilitate N-terminal cleavage reaction. His-38 is stabilized by the solvent-exposed His-5, and can impact N-S acyl shift by direct interaction with the catalytic Cys1. Development of inteins as biotechnological tools or as pathogen-specific novel antimicrobial targets requires a more complete understanding of such unexpected roles of conserved extein residues in protein splicing.

Systematic Network and Meta-analysis on the Antiviral Mechanisms of Probiotics: A Preventive and Treatment Strategy to Mitigate SARS-CoV-2 Infection.

With the alarming rise of infected cases and deaths, COVID-19 is a pandemic, affecting 220 countries worldwide. Until now, no specific treatment is available against SARS-CoV-2. The causal virus SARS-CoV-2 primarily infects lung cells, leading to respiratory illness ranging in severity from the common cold to deadly pneumonia. This, with comorbidities, worsens the clinical outcome, particularly for immunosuppressed individuals with COVID-19. Interestingly, the commensal gut microbiota has been shown to improve lung infections by modulating the immune system. Therefore, fine-tuning of the gut microbiome with probiotics could be an alternative strategy for boosting immunity and treating COVID-19. Here, we present a systematic biological network and meta-analysis to provide a rationale for the implementation of probiotics in preventing and/or treating COVID-19. We have identified 90 training genes from the literature analysis (according to PRISMA guidelines) and generated an association network concerning the candidate genes linked with COVID-19 and probiotic treatment. The functional modules and pathway enrichment analysis of the association network clearly show that the application of probiotics could have therapeutic effects on ACE2-mediated virus entry, activation of the systemic immune response, nlrp3-mediated immunomodulatory pathways, immune cell migration resulting in lung tissue damage and cardiovascular difficulties, and altered glucose/lipid metabolic pathways in the disease prognosis. We also demonstrate the potential mechanistic domains as molecular targets for probiotic applications to combat the viral infection. Our study, therefore, offers probiotics-mediated novel preventive and therapeutic strategies for COVID-19 warfare.

Escherichia coli, a common constituent of benign prostate hyperplasia-associated microbiota induces inflammation and DNA damage in prostate epithelial cells.

BACKGROUND: The role of microbiota in the pathophysiology of benign prostate hyperplasia (BPH), especially in creating an inflammatory milieu may not be avoided. The major objectives of this study were to investigate the microbial composition of BPH tissues, its association with inflammation and check the effect of clinically isolated bacteria on prostate epithelial cells. METHODS: The study includes 36 patients with a pathological diagnosis of BPH. Following strict aseptic measures, tissues were collected after transurethral resection of prostate, multiple pieces of the resected tissues were subjected to histopathological analysis, bacterial culture and genomic DNA extraction. Microbial composition was analyzed by culture and/or next-generation sequencing methods. Annotation of operational taxonomy unit has been done with an in-house algorithm. The extent of inflammation was scored through histological evaluation of tissue sections. The effect of clinical isolates on nuclear factor-κB (NF-κB) activity and induction of DNA-damage in the prostate epithelial cells were evaluated. RESULTS: Histopathological analysis of the BPH tissues showed the presence of inflammation in almost all the tissues with a varied level at different regions of the same tissue section and the level of overall inflammation was different from patients to patients. Microbial culture of tissue samples showed the presence of live bacteria in 55.5% (20 out of 36) of the patient tissues. Majority of the isolates were coagulase-positive Staphylococcus, E. coli and Micrococcus spp. Further, V3 16S rRNA sequencing of the DNA isolated from BPH tissues showed the presence of multiple bacteria and the most common phylum in the BPH tissues were found to be Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. The E. coli, isolated from one of the tissue was able to activate NF-κB and induce DNA damage in prostate epithelial cells. Phospho-histone γH2A.X staining confirmed the presence of cells with damaged DNA lesion in BPH tissues and also correlated with the severity of inflammation. CONCLUSION: Our study has shown that the BPH tissues do have a divergent microbial composition including the commonly found E. coli (phylum Proteobacteria), and these bacteria might contribute to the BPH-associated inflammation and/or tissue damage. The BPH-associated E. coli induced NF-κB signaling and DNA damage in prostate epithelial cells in vitro.

Aquasorbent guargum grafted hyperbranched poly (acrylic acid): A potential culture medium for microbes and plant tissues.

This study reports the synthesis of an unprecedented bio-based aquasorbent guargum-g-hyperbranched poly (acrylic acid); bGG-g-HBPAA by employing graft-copolymerization and "Strathclyde methodology" simultaneously in emulsion and its possible use as a sustainable nutrient bed for the effective growth of Anabaena cylindrica and Vigna radiata seedlings. The formation of bGG-g-HBPAA and the presence of hyperbranched architectures was confirmed from XRD, FTIR, 13C NMR, solubility, intrinsic viscosity, BET surface area/ pore size, SEM and rheology analyses. The synthesized grade with a branching percent of 65.4% and a swelling percentage of 13,300% facilitated maximum growth of the cultured species as compared to guargum and its linear graft. Semi synthetic bGG-g-HBPAA culture medium was optically transparent, dried at a controlled rate, held a huge amount of water for growth, provided sufficient space for unhindered growth and featured dimensional stability.

Clinical, pathological, and molecular investigation of Mycoplasma pulmonis-induced murine respiratory mycoplasmosis in a rat (Rattus norvegicus) colony.

AIM: Mycoplasma pulmonis (MP) remains potentially important rodent pathogen causing murine respiratory mycoplasmosis (MRM) which may go undiagnosed due to its asymptomatic nature. In the present study, we carried out clinical, pathological, and molecular investigations of MP-induced MRM in a rat colony. MATERIALS AND METHODS: Two female Wistar rats were observed to be diseased in animal facility of NISER, Bhubaneswar, and were kept in isolation for further investigation. Both the animals were found to be positive for MP after serological and molecular tests. Thereafter, whole rat colony comprising of 36 animals was segregated based on clinical symptoms and further sampled for histopathological, serological, and molecular investigations. Tracheal washing and infected lung tissue were collected during necropsy examination for DNA extraction. Molecular diagnosis was done by polymerase chain reaction (PCR) assay using species-specific primers. RESULT: Classical symptoms of MP-associated respiratory tract infection were observed in only 2 of 36 infected animals, and most of the animals were found asymptomatic to the disease; however, all the animals were found to be carrier after necropsy and PCR assay. Gross and histopathological finding suggested severe congestion of the lungs along with suppurative and necrotizing pneumonia. The disease is confirmed by molecular diagnosis using species-specific primers in PCR assay. CONCLUSION: MRM may go undiagnosed due to asymptomatic nature. Detailed study of clinical symptoms, pathology, serology, and PCR-based molecular approach may aid in health monitoring and detection of MRM in a rodent colony reared for experimental purpose.