Project description:Staphylococcus aureus (S. aureus) is one of the most dominant human pathogen, responsible for a variety of chronic and severe infections. As a classic traditional Chinese medicine (TCM) formula, Epidemic Prevention Sachets have been used clinically for centuries to treat infectious diseases. The antimicrobial activity of the essential oil (EO) from Epidemic Prevention Sachets against the S. aureus has not been investigated. In this study, the EO was tested for its antimicrobial activity against S. aureus. We identified that the EOs has high activity against S. aureus. It showed higher activity than the known antibacterial drug combination of Penicillin streptomycin. The same results were demonstrated by transmission electron microscopy. The impact of the EO on transcription of genes from S. aureus was analyzed. SAOUHSC_01002, SAOUHSC_02444, SAOUHSC_00282 and SAOUHSC_00325, which are involved in cation transport (GO:0006812), were significantly affected by the essential oil as defined in the Gene Ontology Biological Process (GO BP), whereas SAOUHSC_00114 and SAOUHSC_03000, which are involved in the protein tyrosine kinase modulator pathway (K19420), were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Analysis of clusters of orthologous groups (COG) found that there are differences in multiple metabolic pathways, mainly including secondary biosynthesis metabolism, biofilm related genes and energy metabolism. Our study indicates that the essential oil from Epidemic Prevention Sachets is an effective herbal formula against S. aureus.
Project description:Antimicrobial resistance poses a global threat. Natural-origin compounds represent a valuable source of antimicrobial agents used in both human and veterinary medicine. However, understanding their mechanisms of action at the molecular level is essential to support their safe and effective application. In this study, we evaluated the antimicrobial potential of trans-cinnamaldehyde (CNMA), a major constituent of cinnamon bark oil, which can account for up to 80% of the oil content in species such as Cinnamomum zeylanicum and cassia. Although CNMA exhibits broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria, its precise mode of action remains incompletely understood. To elucidate CNMA's molecular effects, we performed transcriptomic profiling of Escherichia coli MG1655 wild-type (GSE252441) and its ∆relA mutant upon treatment with a sub-inhibitory concentration (0.25×MIC) of CNMA. Total RNA was isolated and assessed using the Agilent Bioanalyzer 2100, and high-throughput sequencing was conducted on the Illumina NovaSeq6000 platform, generating ~30 million paired-end 101 bp reads per sample. The reference genome and annotations of E. coli MG1655 were obtained from GenBank. RNA-seq data were analyzed to identify differentially expressed genes (DEGs) compared to untreated controls at 30 and 60 min post-treatment, using thresholds of p ≤ 0.05 and |log₂FC| ≥ 2. Transcriptomic analysis revealed profound transcriptional remodeling. The most significantly enriched functional categories included genes involved in the tricarboxylic acid (TCA) cycle, flagellar biosynthesis, amino acid transport, and oxidoreductase activity. These findings indicate that CNMA-treated E. coli undergoes a marked metabolic downshift and initiates stress responses. These transcriptomic results were supported by complementary assays showing reduced growth kinetics, cytoplasmic shrinkage, NAD/NADH imbalance, and induction of the stringent response via elevated (p)ppGpp levels. Together, our findings suggest that CNMA disrupts bacterial fitness by impairing core metabolic and regulatory pathways, ultimately leading to loss of viability. Funding: This research was funded by the National Science Center, Poland (grant SONATA UMO-2018/31/D/NZ7/02258 to D.N.)
Project description:The balance between tolerogenic and inflammatory responses determines immune homeostasis in the gut. Dysbiosis and a defective host defense against invading intestinal bacteria can shift this balance via bacterial-derived metabolites and trigger chronic inflammation. We show that the short chain fatty acid butyrate modulates monocyte to macrophage differentiation by promoting antimicrobial effector functions. The presence of butyrate modulates antimicrobial activity via a shift in macrophage metabolism and reduction in mTOR activity. This mechanism is furthermore dependent on the inhibitory function of butyrate on histone deacetylase 3 (HDAC3) driving transcription of a set of antimicrobial peptides including calprotectin. The increased antimicrobial activity against several bacterial species is not associated with increased production of conventional cytokines. Butyrate imprints antimicrobial activity of intestinal macrophages in vivo. Our data suggest that commensal bacteria derived butyrate stabilize gut homeostasis by promoting antimicrobial host defense pathways in monocytes that differentiate into intestinal macrophages.
Project description:Aiming to reduce food spoilage, the present study developed novel highly active food-grade preservatives affecting a wide range of bacteria. For this purpose, storage proteins were extracted from food plants. After enzymatic hydrolysis by the digestive protease chymotrypsin, the peptide profiles were analyzed by ultrahigh-performance micro-liquid chromatography–triple quadrupole time-of-flight tandem mass spectrometry. Virtual screening identified 21 potential antimicrobial peptides in chickpea legumin. Among those, the peptides Leg1 (RIKTVTSFDLPALRFLKL) and Leg2 (RIKTVTSFDLPALRWLKL) exhibited antimicrobial activity against 16 different bacteria, including pathogens, spoilage-causing bacteria and two antibiotic-resistant strains. Minimum inhibitory concentrations (MIC) down to 15.6 µM indicated 10–1,000-fold higher activity of the novel antimicrobial peptides compared to conventional food preservatives. Moreover, Leg1 and Leg2 showed bactericidal activity in bacterial suspension and during the storage of raw pork meat.
Project description:Reversal reactions (RR) in leprosy provide a unique opportunity to study the dynamics of the immune response against intracellular bacteria in humans. These episodes are often severe and difficult to treat, frequently progressing to permanent disabilities. We performed RNA sequencing on paired skin biopsy specimens from nine leprosy patients before and during RR, identifying a 64-gene antimicrobial response signature that correlated with the concomitant decrease in Mycobacterium leprae bacilli in RR patients. The upstream regulators of this signature included both innate (IL-1β, TNF) and adaptive (IFN-γ, IL-17) cytokines, indicating induction of both Th1 and Th17 responses. Using a machine learning classifier to identify proteins with predicted membrane-permeating activity, we identified 28 genes in RR with previously unknown direct antimicrobial activity, including S100A8. We validated the antimicrobial activity of four proteins (S100A7, S100A8, CCL17, CCL19) against M. leprae in infected macrophages and axenic culture. Scanning electron microscopy revealed distinct membrane damage in bacteria exposed to these antimicrobial proteins. Our findings reveal dynamic antimicrobial gene regulation during RR and identify new host defense effectors, supporting therapeutic strategies that boost Th1/Th17 function to improve outcomes in mycobacterial infections.
Project description:Herein, we used C. acnes as a model to elucidate the antimicrobial machinery of the TH17 subset. We generated C. acnes-specific antimicrobial TH17 clones (AMTH17) with varying antimicrobial activity against C. acnes, to enable us to study mechanisms by which TH17 cells kill bacteria. We show that C. acnes-induced AMTH17 clones represent a subset of CD4+ TEM and TEMRA cells. RNA-seq analysis of AMTH17 indicate transcripts encoding antimicrobial molecules such as GNLY, GZMB, PRF1 and histone H2B, whose expression correlates with killing activity. Additionally, we validated that AMTH17-mediated killing is a general mechanism that can target C. acnes and other bacterial species. Scanning electron microscopy reveal that AMTH17s can release T cell extracellular traps composed of lysine and arginine-rich histones such as H2B and H4 that entangle C. acnes. This study identifies a functionally distinct subpopulation of TH17 cells with an ability to secrete antimicrobial proteins and form extracellular T cell traps to capture and kill bacteria.
Project description:The surge of antimicrobial resistance in recent decades threatens efficacy of current antibiotics, particularly against Pseudomonas aeruginosa, a highly resistant gram-negative pathogen. The asymmetric outer membrane of P. aeruginosa combined with its array of efflux pumps provide a barrier to xenobiotic intracellular accumulation, thus making the discovery of novel drugs with whole cell antibacterial activity very challenging. We adapted PROSPECT, a genome-wide, target-based, whole cell screening strategy, to take a focused approach to discover small molecule probes with specific activity against engineered P. aeruginosa mutants depleted for essential proteins localized at the outer membrane. We identified BRD1401, a small molecule that has specific activity against a P. aeruginosa mutant depleted for the essential lipoprotein, OprL. Genetic studies identified a novel link between OprL and the non-essential, outer membrane β barrel protein, OprH, to modulate BRD1401 activity. BRD1401 directly bound to OprH to disrupt the known interaction between OprH and lipopolysaccharide (LPS) in vitro and in whole bacteria. OprH also biochemically interacted with OprL, thus providing a link between outer membrane and peptidoglycan in P. aeruginosa. Thus, a whole cell, multiplexed screen against P. aeruginosa identified a species-specific inhibitor and probe molecule that revealed novel pathogen biology.
Project description:The surge of antimicrobial resistance in recent decades threatens efficacy of current antibiotics, particularly against Pseudomonas aeruginosa, a highly resistant gram-negative pathogen. The asymmetric outer membrane of P. aeruginosa combined with its array of efflux pumps provide a barrier to xenobiotic intracellular accumulation, thus making the discovery of novel drugs with whole cell antibacterial activity very challenging. We adapted PROSPECT, a genome-wide, target-based, whole cell screening strategy, to take a focused approach to discover small molecule probes with specific activity against engineered P. aeruginosa mutants depleted for essential proteins localized at the outer membrane. We identified BRD1401, a small molecule that has specific activity against a P. aeruginosa mutant depleted for the essential lipoprotein, OprL. Genetic studies identified a novel link between OprL and the non-essential, outer membrane β barrel protein, OprH, to modulate BRD1401 activity. BRD1401 directly bound to OprH to disrupt the known interaction between OprH and lipopolysaccharide (LPS) in vitro and in whole bacteria. OprH also biochemically interacted with OprL, thus providing a link between outer membrane and peptidoglycan in P. aeruginosa. Thus, a whole cell, multiplexed screen against P. aeruginosa identified a species-specific inhibitor and probe molecule that revealed novel pathogen biology.
Project description:Honokiol (HNK), one of the main medicinal components in Magnolia officinalis, possesses antimicrobial activity against a variety of pathogenic bacteria and fungi.S. cerevisiae is a model eukaryote used for investigating the cellular and molecular mechanisms of anti-fungal drugs. To explore the molecular mechanism of its anti-fungal activity, we determined the effects of HNK on the mRNA expression profile of Saccharomyces cerevisiae using a DNA microarray approach.
Project description:Enterocin AS-48 is produced by Enterococcus faecalis S48 to compete with other bacteria in their environment. Due to its activity against various Gram positive and some Gram negative bacteria it has clear potential for use as a food preservative. Here, we studied the effect of enterocin AS-48 challenges on vegetative cells of Bacillus cereus ATCC 14579 by use of transcriptome analysis. Control: Wild type against Target: Enterocin AS-48 challenge A supplementary file containing processed data of all samples combined is linked below. Mn column is the lowess normalized LN (Target/Control).