Phage specificity primarily relies on host cell-surface receptors. However, integrating cas genes and guide RNAs into phage genomes could enhance their target specificity and regulatory effects. In this study, we developed a CRISPR-Cas12f1 system-equipped bacteriophage λ model capable of detecting Escherichia coli target genes. We demonstrated that synthetic λ phages carrying Cas12f1-sgRNA can effectively prevent lysogen formation. Furthermore, we showcased that truncating the 3'-end of sgRNA enables precise identification of single-nucleotide variations in the host genome. Moreover, infecting E. coli strains carrying various stx2 gene subtypes encoding Shiga toxin with bacteriophages harboring Cas12f1 and truncated sgRNAs resulted in the targeted elimination of strains with matching subtype genes. These findings underscore the ability of phages equipped with the CRISPR-Cas12f1 system to precisely control microbial hosts by recognizing genomic sequences with high resolution.

Pyridoxal 5'-phosphate (PLP)-dependent enzymes participate in various reactions involved in methionine and cysteine metabolism. The representative foodborne pathogen Staphylococcus aureus expresses the PLP-dependent enzyme MccB, which exhibits both cystathionine gamma-lyase (CGL) and cysteine desulfhydrase activities. In this study, we investigated the role of Ser323 in MccB, a conserved residue in many PLP-dependent enzymes in the transsulfuration pathway. Our findings reveal that Ser323 forms a hydrogen bond with the catalytic lysine in the absence of PLP, and upon internal aldimine formation, PLP-bound lysine is repositioned away from Ser323. Substituting Ser323 with alanine abolishes the enzymatic activity, similar to mutations at the catalytic lysine site. Spectroscopic analysis suggests that Ser323 is essential for the rapid formation of the internal aldimine with lysine in wild-type MccB. This study highlights the crucial role of Ser323 in catalysis, with broader implications for other PLP-dependent enzymes, and enhances our understanding of the molecular mechanisms involved in the selective control of foodborne pathogenic bacteria.

Bacteria-free reverse genetics techniques are crucial for the efficient generation of recombinant viruses, bypassing the need for labor-intensive bacterial cloning. These methods are particularly relevant for studying the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. This study compared the efficiency of three bacteria-free approaches—circular polymerase extension reaction (CPER) with and without nick sealing and infectious sub-genomic amplicons (ISA)—to bacterial artificial chromosome (BAC)-based technology for rescuing SARS-CoV-2. Significant differences in viral titers following transfection were observed between methods. CPER with nick sealing generated virus titers comparable to those of the BAC-based method and 10 times higher than those of the standard CPER. In contrast, ISA demonstrated extremely low efficiency, as cytopathic effects were detected only after two passages. All rescued viruses exhibited replication kinetics consistent with those of the original strain, with no significant deviation in replication capacity. Furthermore, the utility of CPER and ISA in genetically modifying SARS-CoV-2 was demonstrated by successfully inserting the gene encoding green fluorescent protein into the genome. Overall, this study underscores the potential of bacteria-free methods, such as CPER and ISA, in advancing SARS-CoV-2 research while highlighting their significant differences in efficiency.

Pseudomonas aeruginosa secretes three major proteases: elastase B (LasB), protease IV (PIV), and elastase A (LasA), which play crucial roles in infection and pathogenesis. These proteases are activated sequentially from LasB in a proteolytic cascade, and LasB was previously thought to undergo auto-activation. However, our previous study suggested that LasB cannot auto-activate independently but requires additional quorum sensing (QS)-dependent factors for activation, as LasB remained inactive in QS-deficient P. aeruginosa (QS^-) even under artificial overexpression. In this study, we provide evidence for the existence of a LasB inhibitor in QS^- mutants: inactive LasB overexpressed in QS^- strains was in its processed form and could be reactivated upon purification; when full-length LasB was overexpressed in Escherichia coli, a heterologous bacterium lacking both LasB activators and inhibitors, the protein underwent normal processing and activation; and purified active LasB was significantly inhibited by culture supernatant (CS) from QS^- strains but not by CS from QS⁺ strains. These findings demonstrate that a LasB inhibitor exists in QS^- strains, and in its absence, LasB can undergo auto-activation without requiring an activator. Based on these results, we propose an updated hypothesis: the QS-dependent LasB activator functions by removing the LasB inhibitor rather than acting directly on LasB itself, thus preventing premature LasB activation until QS response is initiated.

Synbiotics have become a new-age treatment tool for limiting the progression of metabolic dysfunction-associated steatotic liver disease; however, inclusive comparisons of various synbiotic treatments are still lacking. Here, we have explored and evaluated multiple synbiotic combinations incorporating three distinctive prebiotics, lactitol, lactulose and fructooligosaccharides. Of the synbiotic treatments evaluated, a combination of fructooligosaccharides and probiotics (FOS+Pro) exhibited superior protection against western diet-induced liver degeneration. This synbiotic (FOS+Pro) combination resulted in the lowest body weight gains, liver weights and liver/body weight ratios. The FOS+Pro synbiotic combination substantially alleviated liver histopathological markers and reduced serum AST and cholesterol levels. FOS+Pro ameliorated hepatic inflammation by lowering expression of proinflammatory markers including TNF-α, IL-1β, IL-6, and CCL2. FOS+Pro significantly improved steatosis by restricting the expression of lipid metabolic regulators (ACC1, FAS) and lipid transporters (CD36) in the liver. These findings are critical in suggesting that synbiotic treatments are capable of restraining western diet-induced metabolic dysfunction in the liver. Additionally, this study demonstrated that adding probiotic strains amplified the effectiveness of fructooligosaccharides but not all prebiotics.

Alcohol consumption can lead to the accumulation of harmful metabolites, such as acetaldehyde, contributing to various adverse health effects, including hangovers and liver damage. This study presents a comprehensive genomic and functional analysis of Leuconostoc suionicum VITA-PB2, a lactic acid bacterial strain isolated from kimchi, to elucidate its role in enhancing alcohol and acetaldehyde metabolism. Genomic characterization revealed key genes encoding alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), providing insights into the metabolic capabilities of strain VITA-PB2. Phylogenomic analyses confirmed its taxonomic classification and genetic similarity to other Leuconostoc species. Functional validation through in vitro and in vivo experiments demonstrated superior ethanol and acetaldehyde decomposition abilities of strain VITA-PB2, with significant reductions in blood ethanol and acetaldehyde levels observed in rats administered with the strain. Further analysis indicated that while hepatic ADH activity did not significantly increase; however, ALDH expression was elevated. This suggests that the microbial ADH of strain VITA-PB2 contributed to ethanol breakdown, while both microbial and host ALDH facilitated acetaldehyde detoxification. These findings highlight the potential of strain VITA-PB2 as a functional probiotic for mitigating the toxic effects of alcohol consumption.

Salmonella enterica is a clinically significant oro-fecal pathogen that causes a wide variety of illnesses and can lead to epidemics. S. enterica expresses a lot of virulence factors that enhance its pathogenesis in host. For instance, S. enterica employs a type three secretion system (T3SS) to translocate a wide array of effector proteins that could change the surrounding niche ensuring suitable conditions for the thrive of Salmonella infection. Many antimicrobials have been recently introduced to overcome the annoying bacterial resistance to antibiotics. Enoxacin is member of the second-generation quinolones that possesses a considerable activity against S. enterica. The present study aimed to evaluate the effect of enoxacin at sub-minimum inhibitory concentration (sub-MIC) on S. enterica virulence capability and pathogenesis in host. Enoxacin at sub-MIC significantly diminished both Salmonella invasion and intracellular replication within the host cells. The observed inhibitory effect of enoxacin on S. enterica internalization could be attributed to its ability to interfere with translocation of the T3SS effector proteins. These results were further confirmed by the finding that enoxacin at sub-MIC down-regulated the expression of the genes encoding for T3SS-type II (T3SS-II). Moreover, enoxacin at sub-MIC lessened bacterial adhesion to abiotic surface and biofilm formation which indicates a potential anti-virulence activity. Importantly, in vivo results showed a significant ability of enoxacin to protect mice against S. enterica infection and decreased bacterial colonization within animal tissues. In nutshell, current findings shed light on an additional mechanism of enoxacin at sub-MIC by interfering with Salmonella intracellular replication. The outcomes presented herein could be further invested in conquering bacterial resistance and open the door for additional effective clinical applications.

Chronic toxoplasmosis is caused by Toxoplasma gondii bradyzoites. This study assessed six candidate small molecule kinase inhibitors (SMKIs) against bradyzoites (ME49 strain), the reactivated form of the parasite resulting from the rupture of brain cysts. Bradyzoites were obtained from mouse brain cysts, cultured in ARPE-19 cells, and treated with afatinib and neratinib (HER2/HER4 inhibitors), ACTB-1003 and regorafenib (VEGFR-2 inhibitors), or altiratinib and foretinib (c-MET inhibitors). The effects on the growth of T. gondii were analyzed by western blot and immunofluorescence assay. Changes in the host cells were assessed using markers for cell viability, apoptosis, necrosis, and autophagy. All inhibitors blocked the growth of bradyzoites, although afatinib was less effective. Afatinib enhanced autophagy signals, while ACTB-1003 and neratinib affected mitochondrial biosynthesis and mitophagy. Altiratinib demonstrated an effect against bradyzoites at the lowest concentration with minimal impact on the host cells. It may be effective in blocking the reactivation of brain cysts in immunodeficiency patients caused by bradyzoites.

This review explores current advancements in microbiome functional analysis enabled by next-generation sequencing technologies, which have transformed our understanding of microbial communities from mere taxonomic composition to their functional potential. We examine approaches that move beyond species identification to characterize microbial activities, interactions, and their roles in host health and disease. Genome-scale metabolic models allow for in-depth simulations of metabolic networks, enabling researchers to predict microbial metabolism, growth, and interspecies interactions in diverse environments. Additionally, computational methods for predicting metabolite profiles offer indirect insights into microbial metabolic outputs, which is crucial for identifying biomarkers and potential therapeutic targets. Functional pathway analysis tools further reveal microbial contributions to metabolic pathways, highlighting alterations in response to environmental changes and disease states. Together, these methods offer a powerful framework for understanding the complex metabolic interactions within microbial communities and their impact on host physiology. While significant progress has been made, challenges remain in the accuracy of predictive models and the completeness of reference databases, which limit the applicability of these methods in under-characterized ecosystems. The integration of these computational tools with multi-omic data holds promise for personalized approaches in precision medicine, allowing for targeted interventions that modulate the microbiome to improve health outcomes. This review highlights recent advances in microbiome functional analysis, providing a roadmap for future research and translational applications in human health and environmental microbiology.

With the advent of whole-genome sequencing, opportunities to investigate the population structure, transmission patterns, antimicrobial resistance profiles, and virulence determinants of Streptococcus pneumoniae at high resolution have been increasingly expanding. Consequently, a user-friendly bioinformatics tool is needed to automate the analysis of Streptococcus pneumoniae whole-genome sequencing data, summarize clinically relevant genomic features, and further guide treatment options. Here, we developed PneusPage, a web-based tool that integrates functions for species prediction, molecular typing, drug resistance determination, and data visualization of Streptococcus pneumoniae. To evaluate the performance of PneusPage, we analyzed 80 pneumococcal genomes with different serotypes from the Global Pneumococcal Sequencing Project and compared the results with those from another platform, PathogenWatch. We observed a high concordance between the two platforms in terms of serotypes (100% concordance rate), multilocus sequence typing (100% concordance rate), penicillin-binding protein typing (88.8% concordance rate), and the Global Pneumococcal Sequencing Clusters (98.8% concordance rate). In addition, PneusPage offers integrated analysis functions for the detection of virulence and mobile genetic elements that are not provided by previous platforms. By automating the analysis pipeline, PneusPage makes whole-genome sequencing data more accessible to non-specialist users, including microbiologists, epidemiologists, and clinicians, thereby enhancing the utility of whole-genome sequencing in both research and clinical settings. PneusPage is available at https://pneuspage.minholee.net/.

Systemic sclerosis (SSc) is a chronic autoimmune disorder characterised by skin fibrosis and internal organ involvement. Disruptions in the microbial communities on the skin may contribute to the onset of autoimmune diseases that affect the skin. However, current research on the skin microbiome in SSc is lacking. This study aimed to investigate skin microbiome associated with disease severity in SSc. Skin swabs were collected from the upper limbs of 46 healthy controls (HCs) and 36 patients with SSc. Metagenomic analysis based on the 16S rRNA gene was conducted and stratified by cutaneous subtype and modified Rodnan skin score (mRSS) severity. Significant differences in skin bacterial communities were observed between the HCs and patients with SSc, with further significant variations based on subtype and mRSS severity. The identified biomarkers were Bacteroides and Faecalibacterium for patients with diffuse cutaneous SSc with high mRSS (≥ 10) and Mycobacterium and Parabacteroides for those with low mRSS (< 10). Gardnerella, Abies, Lactobacillus, and Roseburia were the biomarkers in patients with limited cutaneous SSc (lcSS) and high mRSS, whereas Coprococcus predominated in patients with lcSS and low mRSS. Cutaneous subtype analysis identified Pediococcus as a biomarker in the HCs, whereas mRSS analysis revealed the presence of Pseudomonas in conjunction with Pediococcus. In conclusion, patients with SSc exhibit distinct skin microbiota compared with healthy controls. Bacterial composition varies by systemic sclerosis cutaneous subtype and skin thickness.

Korean Red ginseng has emerged as a potent candidate in the fight against various viral infections, demonstrating significant efficacy both in vitro and in vivo, particularly against influenza A viruses. Despite substantial evidence of its antiviral properties, the detailed molecular mechanisms through which it reduces viral lethality remain insufficiently understood. Our investigations have highlighted the superior effectiveness of Korean Red ginseng against influenza viruses, outperforming its effects on numerous other viral strains. We aim to uncover the specific mechanisms by which Korean Red ginseng exerts its antiviral effects, focusing on influenza A viruses. Our prior studies have identified the role of Z-DNA-binding protein 1 (ZBP1), a signaling complex involved in inducing programmed cell death in response to influenza virus infection. Given the critical role of ZBP1 as a sensor for viral nucleic acid, we hypothesize that Korean Red ginseng may modulate the ZBP1-derived cell death pathway. This interaction is anticipated to enhance cell death while concurrently suppressing viral protein expression, offering novel insights into the antiviral mechanism of Korean Red ginseng against influenza A viruses.