Search Results (307)

Pseudomonas aeruginosa (P. aeruginosa) forms biofilms that are difficult to eliminate. The matrix protects the cells, efflux pumps reduce intracellular drug levels, and dormant subpopulations survive treatment. Routine minimum inhibitory concentration (MIC) testing does not account for these features, which helps explain why infections often continue even when therapy appears appropriate. This review describes how quorum-sensing (QS) and cyclic di-guanosine monophosphate (c-di-GMP) regulate matrix production, efflux activity, and dormancy within P. aeruginosa biofilms. Important matrix components, including Psl, Pel, alginate, and extracellular DNA, slow the movement of antimicrobial agents. Regulatory proteins such as sagS and brlR increase the activity of the MexAB-OprM and MexEF-OprN efflux systems, further reducing intracellular drug concentrations. Oxygen and nutrient limitation promote persister cells and viable but nonculturable cells, with both having the ability to survive antibiotic levels that would normally be lethal. These defenses explain the gap between MIC values and biofilm-specific measurements, such as the minimum biofilm inhibitory concentration and the minimum biofilm eradication concentration. This review also summarizes emerging antibiofilm strategies. These include QS inhibitors, compounds that lower c-di-GMP, such as nitric oxide donors, nanoparticles, depolymerases, bacteriophages, and therapies that are directed at host targets. Modern diagnostic tools, such as confocal laser scanning microscopy, optical coherence tomography, and Raman spectroscopy, improve detection and guide treatment planning. A staged therapeutic approach is presented that begins with the dispersal or loosening of the matrix, continues with targeted antibiotics, and concludes with support for immune clearance. Viewing these strategies within a One Health framework highlights the role of biofilms in clinical disease and in environmental reservoirs and supports more effective surveillance and prevention. Full article

Listeria monocytogenes is a major foodborne pathogen, responsible for severe listeriosis outbreaks associated with contaminated foods. This study reports the comparative genomic analysis of three novel L. monocytogenes strains C5, A2D9 and A2D10, obtained from dairy and clinical sources. Hybrid genome sequencing with Oxford-Nanopore and Illumina technologies provided high-quality complete chromosomes. Phylogenomic analysis revealed a highly conserved core genome alongside accessory genome diversity. Strain C5 belonged to sequence type ST2, while A2D9 and A2D10 were assigned to ST155 and ST1, respectively. All strains exhibited close genomic relatedness to isolates from dairy animals and/or the dairy environment. Functional analysis identified conserved metabolic functions across all genomes. A total of 40 virulence genes were detected, including the LIPI-1 island in all strains and the LIPI-3 operon exclusively in A2D10, indicating a potential hypervirulent phenotype consistent with its ST1 background and the associated fatal clinical outcome. All strains exhibited similar antimicrobial resistance profiles typical of L. monocytogenes and diverse defense systems. The newly sequenced strains provide a valuable resource for functional analyses of the mechanisms underlying adaptation of L. monocytogenes to diverse environments. Full article

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse effect of antiresorptive and antiangiogenic therapies, yet its molecular mechanisms remain poorly defined. The present study employed an analysis of microarray data (GSE7116) from peripheral blood mononuclear cells of patients with multiple myeloma, myeloma patients with MRONJ, and healthy controls. Differentially expressed genes were identified using the limma package, followed by functional enrichment analysis, weighted gene co-expression network analysis, and LASSO regression and CytoHubba network ranking. The predictive performance was validated by means of nested cross-validation, Firth logistic regression, and safe stratified 0.632+ bootstrap ridge regression. The profiling revealed distinct gene expression patterns between the groups: the upregulation of ribosomal and translational pathways, as well as the suppression of neutrophil degranulation and antimicrobial defense mechanisms, and identified key candidate genes, including PDE4B, JAK1, ETS1, EIF4A2, FCMR, IGKV4-1, and XPO7. These genes demonstrated substantial discriminatory capability, with an area under the curve ranging from 0.95 to 0.99, and were found to be functionally linked to immune system dysfunction, cytokine signaling, NF-κB activation, and a maladaptive stress response. These findings link MRONJ to systemic immune-inflammatory imbalance and translational stress disruption, offering novel insights and potential biomarkers for diagnosis and risk evaluation. Full article

The hypoxic, cold, and high-ultraviolet radiation environments at high altitude pose severe challenges to mammalian immune and metabolic systems. However, little is known about how captive forest musk deer adapt to high-altitude environments and their seasonal variations. This study analyzed peripheral blood transcriptomes of 33 captive forest musk deer (Moschus berezovskii) at high altitude (~3900 m) and low altitude (~1450 m) during autumn-winter and spring-summer seasons. Results revealed comprehensive immune suppression in the high-altitude group during autumn-winter (downregulation of complement system CFB/C2/C3, interferon pathway genes including FLT3, with only natural killer (NK) cell PRKCQ upregulated), coupled with energy-conserving metabolic reprogramming (altered carbohydrate metabolism, inhibited lipid synthesis, fat mobilization, suppressed protein degradation). During spring-summer, neutrophil antimicrobial responses (SLPI/NCF1/ELANE) and humoral immunity (B cell differentiation genes PAX5/RUNX1; class-switch enzyme AICDA) partially recovered while cellular immunity (IL15/B2M) remained suppressed, accompanied by enhanced anabolic metabolism and adipocyte differentiation. Notably, NK cell-mediated cytotoxicity showed selective enhancement despite comprehensive immune suppression, representing an energy-efficient innate defense strategy. This study provides the first characterization of seasonal immune dynamics in a high-altitude cervid species. These findings reveal persistent immune constraints in high-altitude populations and provide theoretical foundations for disease prevention and health management in captive forest musk deer at high altitudes. Full article

This study investigated the phytochemical composition, antioxidant activity, and safety of Tectona grandis leaf extracts at four maturity stages. Ethanolic extracts were screened for secondary metabolites and analyzed using GC–MS, together with heavy metal determination, phenolic profiling, and antioxidant assays. Preliminary phytochemical screening revealed the presence of alkaloids, flavonoids, glycosides, tannins, saponins, and coumarins, with clear variation among leaf stages. GC–MS analysis detected multiple bioactive constituents, including phytol, n-decanoic acid, and heptadecenal. These compounds have been previously reported to exhibit antioxidant, antimicrobial, and anti-inflammatory properties. Heavy metal analysis showed very low cadmium concentrations (0.001–0.004 mg/kg), undetectable lead levels (<LOD), and trace levels of arsenic concentrations (0.012–0.018 mg/kg), all of which were within safe limits for plant materials. Quantitative assays demonstrated that mature leaves contained the highest total phenolic (8.751 ± 0.018 mg GAE/g DW), total flavonoid (0.359 ± 0.017 mg QE/g DW), and condensed tannin (0.303 ± 0.000 mg CE/g DW) contents. Correspondingly, mature-leaf extracts exhibited the greatest antioxidant capacity, showing 95.88 ± 0.12% inhibition of oxidant activity. The ethanolic extracts exhibited IC₅₀ values ranging from 22.93–50.35 mg/mL, whereas the ascorbic acid standard showed an IC₅₀ of 0.0767 mg/mL, confirming the expected lower potency of crude plant extracts. The strong correlation between phenolic accumulation and antioxidant activity suggests enhanced defense against oxidative stress. The absence of detectable heavy metal contamination, together with the high polyphenolic content, suggests that T. grandis leaves may serve as a safe natural source of antioxidants. These findings demonstrate the strong antioxidant potential of T. grandis leaf extracts, providing a basis for future studies evaluating their functional applications in biological systems. Full article

Toxin–antitoxin (TA) modules represent sophisticated regulatory networks that have evolved from simple plasmid maintenance factors into multifunctional genetic modules orchestrating bacterial stress responses, pathogenesis, and ecological adaptation. This review highlights a compelling correlation between the abundance of toxin–antitoxin (TA) modules and bacterial pathogenicity, as exemplified by Mycobacterium tuberculosis (M.tb), which encodes 118 TA loci—significantly more than the fewer than 10 found in closely related saprophytic species. The clinical significance of TA modules extends beyond traditional stress response roles to encompass antimicrobial persistence, where systems like VapBC and MazEF facilitate dormant subpopulations that survive antibiotic therapy while maintaining chronic infections. Recent discoveries have revealed TA modules as sophisticated bacterial defense mechanisms against bacteriophage infection, with DarTG and ToxIN systems representing novel antiviral immunity components that complement CRISPR-Cas and restriction–modification systems. The immunomodulatory capacity of TA modules demonstrates their role in host–pathogen interactions, where systems such as VapC12 in M.tb promote macrophage polarization toward permissive M2 phenotypes while inducing anti-inflammatory cytokine production. Large-scale genomic analyses reveal that TA modules function as drivers of horizontal gene transfer networks, with their signatures enabling accurate prediction of plasmid community membership and serving as determinants of microbial community structure. The biotechnological applications of TA modules have expanded to include genetic circuit stabilization, biocontainment device construction, and multi-species microbial community engineering, while therapeutic strategies focus on developing multi-target inhibitors against conserved TA protein families as promising approaches for combating drug-resistant bacterial infections. The evolutionary conservation of TA modules across diverse bacterial lineages underscores their fundamental importance as central organizing principles in bacterial adaptation strategies, where their multifunctional nature reflects complex selective pressures operating across environmental niches and host-associated ecosystems. This review provides an integrated perspective on TA modules as dynamic regulatory elements that support bacterial persistence, immune evasion, and ecological versatility, establishing them as genetic elements with truly “many faces and functions” in prokaryotic biology. Full article

Listeria monocytogenes (L. monocytogenes) is a major foodborne pathogen which can invade intestinal epithelial cells and cause severe systemic infection. Probiotics, as well as their surface layer proteins, hold broad promise for enhancing intestinal barrier function and defending against pathogenic invasion. In the present study, the antagonistic effects of surface layer protein ornithine carbamoyltransferase (OTC) from Enterococcus faecium (E. faecium) WEFA23 against L. monocytogenes were systematically evaluated in vitro in human intestinal epithelial Caco-2 cells, including assessments of anti-adhesion and anti-invasion capacity, inflammatory cytokine responses, intestinal barrier integrity, and transcriptomic changes, by comparing the effects of wild-type E. faecium WEFA23 and a previously constructed E. faecium WEFA23 otc gene knockout strain (E. faecium WEFA23 otc^−/−). The results demonstrated that E. faecium WEFA23 achieved significant stronger anti-adhesion and anti-invasion capacity of L. monocytogenes (p < 0.05) in the presence of OTC, potentially through increasing tight junction protein expression, regulating inflammatory cytokines, and modulating the virulence factors of the pathogen. To elucidate the potential mechanism of the inhibitory effect of OTC protein, RNA-seq was performed. The results revealed that the significantly regulated core differentially expressed genes (DEGs), including ADCY2, OARI3, CCL5, and CXCL9, were found to be involved in γ-aminobutyric acid (GABA)-ergic synapse, calcium, and toll-like receptor signaling pathways. These findings demonstrated that OTC is involved in blocking Listeria invasion and revealed the function of the OTC from E. faecium WEFA23 in antimicrobial and intestinal mucosal defense, providing a conceptual foundation for the development of new probiotic intervention strategies in anti-infection. Full article

Background: Periodontitis is a multifactorial inflammatory disease influenced by immune and genetic factors. Certain genetic and immunological disorders, such as Down syndrome (DS), Leukocyte Adhesion Deficiency type I (LAD-I), and Papillon–Lefèvre syndrome (PLS), are associated with early-onset and severe periodontitis. Understanding their molecular and immunological mechanisms is crucial for advancing personalized therapeutic approaches. Methods: A systematic review was conducted following PRISMA 2020 guidelines to compare inflammatory gene expression profiles in patients with periodontitis associated with genetic or immune-mediated disorders and those without systemic conditions. Searches were performed in PubMed, Scopus, Web of Science, and Embase for studies published between 2010 and June 2025. Eligible studies reporting cytokine profiles or inflammatory gene expression were included and analyzed. Results: Six case–control studies met the inclusion criteria: three on DS, two on LAD-I, and one on PLS. DS patients showed increased serum levels of IL-1 beta, TNF-alpha, IL-4, IL-10, and IFN-gamma, with dysregulation of STAT1, STAT3, and SOCS3. LAD-I was characterized by overexpression of IL-17A, IL-6, IL-23, G-CSF, CXCL2, and CXCL5, indicating IL-17–driven inflammation and excessive neutrophil activation. In PLS, cathepsin C deficiency impaired activation of the antimicrobial peptide LL-37, leading to compromised host defense and accelerated tissue breakdown. Conclusions: Patients with periodontitis linked to genetic or immune-mediated disorders exhibit distinct inflammatory gene expression signatures that enhance disease susceptibility and progression. Identifying these immunoinflammatory pathways may guide precision periodontal therapies, although larger, standardized studies are required to validate these findings. Full article

Bacterial diseases of forest trees represent an increasing threat to ecosystem health and the sustainability and resilience of forest management, particularly under changing climate conditions. One of the key yet still insufficiently understood adaptive mechanisms of pathogens is biofilm formation—a structured community of bacterial cells embedded in a matrix of extracellular polymeric substances (EPS), which provides protection against stress factors, biocides, and the host’s defensive responses such as antimicrobial compounds or immune reactions. This paper presents a comprehensive review of current knowledge on the role of biofilms in the bacterial pathogenesis of forest trees, covering their formation mechanisms, molecular regulation, and ecological significance. Four key stages of biofilm development are discussed—adhesion, microcolony formation, EPS production, and dispersion—along with the roles of quorum sensing systems and c-di-GMP-based signaling in regulating these processes. Examples of major tree pathogens are presented, including Pseudomonas syringae, Erwinia amylovora, Xylella fastidiosa, the Brenneria–Gibbsiella complex associated with Acute Oak Decline (AOD) and Lonsdalea populi. Biofilm formation is shown to play a crucial role in the colonization of xylem, leaf surfaces, and tissues undergoing necrosis, where biofilms may stabilize decomposition zones and support saprophytic–pathogenic transitions. In the applied section, the concept of “biofilm-targeted control” is discussed, encompassing both chemical and biological strategies for disrupting biofilm structure—from quorum-sensing inhibitors and EPS-degrading enzymes to the use of biosurfactants and antagonistic microorganisms. The need for in situ research in forest environments and the adaptation of advanced imaging (CLSM, micro-CT) and metagenomic analyses to tree systems is also emphasized. This review concludes that biofilms are not merely a physiological form of bacterial organization but a complex adaptive system essential for the survival and virulence of pathogens in forest ecosystems. Understanding their functions is fundamental for developing sustainable and ecologically safe phytosanitary strategies for forest protection. Full article

Objective: Antimicrobial resistance (AMR) is a top ten threat to global public health, and Malta remains among the highest antibiotic-consuming countries in the European Union. This systematic review aimed to identify barriers and facilitators influencing antimicrobial stewardship in Malta, focusing on general practitioners (GPs) and pharmacists. Methods and Measures: Eligible studies included GPs and/or pharmacists practising in Malta and explored influences on prescribing and/or dispensing. Systematic searches were performed in June 2025 and September 2025 using the following databases MEDLINE, PsycINFO, PsycArticles PubMed, and Google Scholar. Data were extracted using a modified Cochrane template, and quality was assessed using Joanna Briggs Institute tools. Findings were synthesised using the socio-ecological model and mapped to the COM-B framework. Results: Seven studies met inclusion criteria, with a total sample size of 495 participants. Barriers included diagnostic uncertainty, knowledge gaps, misconceptions about AMR, patient expectations, commercial pressures, limited diagnostic and IT infrastructure, and defensive prescribing linked to indemnity insurance. Facilitators included stewardship values, stronger guideline adherence among younger GPs, trust-based GP–patient relationships, GP–pharmacist collaboration, and intervention effects from a social marketing programme. Mapping to COM-B showed barriers and facilitators interacting across capability, opportunity, and motivation. Conclusions: Prescribing in Malta is shaped by diagnostic uncertainty, entrenched habits, patient expectations, and structural gaps. Although the evidence base was limited and partly overlapping, consistent findings across mixed method designs highlighted that effective stewardship will require rapid diagnostics, e-prescribing, over-the-counter enforcement, and GP–pharmacist collaboration, supported by policy reforms aligning indemnity and sick-leave systems with AMR goals. Full article

Skin wound healing is a highly regulated biological process that requires the coordinated activity of multiple cell types. However, this process can be significantly impaired by factors such as metabolic diseases and infections, posing ongoing challenges for current treatment strategies. As a critical defense mechanism for cells and organisms against external threats, antimicrobial peptides (AMPs) hold great potential to enhance both the rate and quality of healing in both acute and chronic wounds. AMPs play a crucial role in promoting skin wound healing through mechanisms such as keratinocyte migration and proliferation, collagen synthesis and tissue remodeling, promotion of angiogenesis, immunomodulatory effects and broad-spectrum antimicrobial activity. Moreover, structural modifications and optimized delivery systems have further enhanced the stability and efficacy of AMPs. This paper explores the mechanisms by which AMPs aid in the healing of damaged skin and reviews the types of AMPs in clinical trials, providing a foundation for their development and clinical application. Full article

The induction of resistance in plants involves prior activation of physiological and biochemical systems in the face of external stimuli, promoting greater tolerance to biotic stresses. Faced with the growing challenge of emerging diseases in agricultural plants and the search for more sustainable phytosanitary practices, natural substances are promising alternatives. Xylopia frutescens, known as “pindaiba-da-folha-pequena”, native to the Brazilian Cerrado and traditionally used as an antimicrobial treatment, is still little-explored in the literature and presents potentially effective compounds for the control of plant diseases. This study characterized the chemical composition and thermal stability of the X. frutescens essential oil (XEO), while evaluating its physiological and phytotoxic effects and the potential for disease control in maize and cowpea plants. The main constituents found in X. frutescens essential oil were nopinone (13.75%), spatulenol (12.94%), myrtenal (12.47%), and β-pinene (11.02%). Thermogravimetric analysis indicated that X. frutescens is highly volatile, with a large mass loss at 94.74 °C. In bioassays, the oil preserved chlorophyll levels at adequate amounts and activated several antioxidant mechanisms, but also showed a dose-dependent phytotoxic effect. In vitro assays further confirmed its antifungal activity against key phytopathogens, supporting its potential use in disease control. A general increase in the activities of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APx) and—partially—chitinase (CHIT) was observed. Catalase (CAT) decreased in both maize and cowpea plants treated with this essential oil but was higher in untreated infected plants. Such enzymatic changes suggest that the oil acts as a natural elicitor of resistance, strengthening biochemical and physiological defenses. Finally, disease severities, as measured by AUDPCs, demonstrated significant reductions in the progress of maize “Curvularia leaf spot” (Curvularia lunata) and cowpea “Web blight” (Rhizoctonia solani). The results highlight the potential of X. frutescens essential oil as an active compound stimulating defense mechanisms for applications in sustainable agricultural systems. Full article

This review reappraises the anti-inflammatory potential of the contact activation system (CAS) in intensive care through an evolutionary lens. The authors propose that coagulation factor XII (FXII) and related components evolved in terrestrial animals as a “foreign-surface sensing–immunothrombosis” module, helping to explain the minimal bleeding phenotype of FXII deficiency and the secondary loss of F12 in marine mammals. CAS shares components with the kallikrein–kinin system (KKS): alpha-coagulation factor XIIa (α-FXIIa) drives coagulation factor XI (FXI) activation to amplify coagulation, whereas betacoagulation factor XIIa (β-FXIIa) activates the KKS to generate bradykinin, promoting vasodilation and vascular leak. Beyond proteolysis, zymogen FXII signals via urokinase-type plasminogen activator receptor (uPAR) to induce neutrophil extracellular trap formation (NETosis), thereby amplifying immunothrombosis. Clinically, the relevance spans sepsis and extracorporeal organ support: pathogens can hijack CAS/KKS to facilitate invasion, and artificial surfaces such as extracorporeal membrane oxygenation (ECMO) circuits chronically trigger contact activation. In animal models, selective inhibition of FXII/FXI prolongs circuit life and attenuates pulmonary edema and inflammation without materially increasing bleeding. The review also catalogs “non-coagulation” roles of CAS members: Activated coagulation factor XI (FXIa) modulates endothelial permeability and smooth-muscle migration, and the FXII heavy chain exhibits direct antimicrobial activity—underscoring CAS as a nexus for coagulation, inflammation, and host defense. Overall, CAS inhibitors may couple “safe anticoagulation” with “cascade-level anti-inflammation,” offering a testable translational path for organ protection in the ICU alongside infection control and informing combined, precision strategies for anticoagulation and anti-inflammatory therapy. Full article

The gut microbiota of Drosophila melanogaster offers a simplified yet powerful system to study conserved mechanisms of host–microbe interactions. Unlike the highly complex mammalian gut microbiota, which includes hundreds of species, the fly gut harbors a small and defined community dominated by Lactobacillus and Acetobacter. Despite its low diversity, this microbiota exerts profound effects on host physiology. Commensal bacteria modulate nutrient acquisition, regulate insulin/TOR signaling, and buffer dietary imbalances to support metabolic homeostasis and growth. They also influence neural and behavioral traits, including feeding preferences, mating, and aggression, through microbial metabolites and interactions with host signaling pathways. At the immune level, microbial molecules such as peptidoglycan, acetate, uracil, and cyclic dinucleotides activate conserved pathways including Imd, Toll, DUOX, and STING, balancing antimicrobial defense with tolerance to commensals. Dysbiosis disrupts this equilibrium, accelerating aging, impairing tissue repair, and contributing to tumorigenesis. Research in Drosophila demonstrates how a low-diversity microbiota can shape systemic host biology, offering mechanistic insights relevant to human health and disease. Full article

CRISPR-Cas systems are best known as adaptive immune defenses in prokaryotes, but they also function as versatile regulators bridging bacterial immunity with host-related processes. Beyond neutralizing invasive phages and plasmids, these systems influence core aspects of bacterial physiology, such as modulating gene expression, stress responses, biofilm formation, quorum sensing, and virulence. Notably, CRISPR-mediated regulation can facilitate immune evasion at the host-pathogen interface, underscoring these systems as central orchestrators of microbial survival and host interactions. In addition, CRISPR-Cas has rapidly become a cornerstone of synthetic biology and microbiome engineering. Recent strategies repurpose native and engineered CRISPR systems to precisely modulate microbiome composition or deliver sequence-specific antimicrobials, underscoring the expanding translational potential of this system. Collectively, emerging insights highlight both the canonical immune function and non-canonical regulatory roles of CRISPR-Cas, as well as their broad biological and biotechnological relevance. This review provides a critical synthesis of these developments, illustrating how CRISPR-Cas bridges adaptive immunity and microbial physiology, and outlines future directions for harnessing this duality to deepen understanding of microbial physiology and inform new translational applications. Full article