Search Results (622)

The threats leading to the extinction of humanity accelerate the evolution and development of materials that are capable of providing conditions for preserving health and, implicitly, life. In our work, we developed drug delivery systems based on mesoporous silica which can deliver an antibiotic, bacitracin, in a more controlled manner. The synthesis of the FDU-12 was performed through a sol–gel method and alternatively functionalized with -NH₂ groups or with poly(N-acryloylmorpholine) chains. The loading of bacitracin was performed using the vacuum-assisted method we successfully used to load these mesoporous materials preferentially within the pores as proved by the TGA-DSC results. The release was performed in two types of simulated body fluid (SBF) and this process was evaluated with chromatographic method using UV detection. The obtained data were fitted in three mathematical models of kinetic drug release (Weibull model, Korsmeyer–Peppas model, and nonlinear regression). The antimicrobial evaluation demonstrated that bacitracin-loaded FDU-12 formulations exhibited strong activity against both reference and clinical Staphylococcus strains. At sub-inhibitory concentrations, all formulations significantly reduced microbial adherence and biofilm formation, although certain strain-dependent stimulatory effects were observed. Furthermore, exposure to sub-MIC levels modulated the production of soluble virulence factors (hemolysins, lipase, and amylase), in a formulation- and strain-dependent manner, underscoring the ability of surface-functionalized FDU-12 carriers to influence bacterial pathogenicity while enhancing antimicrobial efficacy. Full article

Maize (Zea mays L.) is a major economic crop highly susceptible to Colletotrichum graminicola, the causal agent of anthracnose leaf blight, which causes substantial annual yield losses. This fungal pathogen employs numerous effectors to manipulate plant immunity, yet the functions of many secreted proteins during biphasic infection remain poorly characterized. In this study, we identified CgMas2, a candidate secreted protein in C. graminicola and a homolog of Magnaporthe oryzae MoMas2. Deletion of CgMAS2 in the wild-type strain CgM2 did not affect fungal vegetative growth or conidial morphology but significantly impaired virulence on maize leaves. Leaf sheath infection assays revealed that CgMas2 is required for biotrophic invasive hyphal growth, as the mutant showed defective spreading of invasive hyphae to adjacent cells. Subcellular localization analysis indicated that CgMas2 localizes to the cytoplasm of conidia and to the primary infection hyphae. Furthermore, DAB staining demonstrated that disrupt of CgMAS2 leads to host reactive oxygen species (ROS) accumulation. Comparative transcriptome analysis of maize infected with ΔCgmas2 versus CgM2 revealed enrichment of GO terms related to peroxisome and defense response, along with up-regulation of benzoxazinoid biosynthesis genes (benzoxazinone biosynthesis 3, 4 and 5) at 60 h post-inoculation (hpi). Conversely, six ethylene-responsive transcription factors (ERF2, ERF3, ERF56, ERF112, ERF115 and ERF118) involved in ethylene signaling pathways were down-regulated at 96 hpi. These expression patterns were validated by RT-qPCR. Collectively, our results demonstrate that CgMas2 not only promotes invasive hyphal growth during the biotrophic stage but may also modulate phytohormone signaling and defense compound biosynthesis during the necrotrophic phase of infection. Full article

Background: Antifungal resistance among Candida species and related genera, coupled with the lack of new drugs, poses a significant threat to public health. Several studies have demonstrated a relationship between virulence factors and resistance. Current objectives include identifying new targets and searching for new natural molecules. Carvacrol, a natural phenolic compound, has been shown to have antimicrobial properties; however, its impact on the virulence of species other than Candida albicans and related yeast genera remains underexplored. Methods: The antifungal activity of carvacrol was evaluated against clinical isolates of Candidozyma auris, Meyerozyma guilliermondii, and Candida dubliniensis, as well as its effect on adhesion, hydrophobicity, biofilm formation and osmotic stress tolerance. In vivo activity was assessed using the Galleria mellonella infection model at MIC concentrations. Results: Carvacrol inhibited adherence and significantly reduced both early and preformed biofilms in M. guilliermondii and C. dubliniensis. In C. auris, the compound produced a modest reduction in biofilm activity but significantly enhanced larval survival in the in vivo model (~20%, p < 0.01). Carvacrol also induced increased tolerance of C. auris to osmotic stress, suggesting activation of adaptive pathways. Conclusions: Carvacrol exhibits species-specific effects, acting as an antivirulence modulator in M. guilliermondii and C. dubliniensis and attenuating virulence in vivo in C. auris. These findings support the potential of carvacrol as an adjuvant antifungal strategy, particularly against C. auris, and highlight the relevance of targeting virulence traits to reduce selective pressure and limit antifungal resistance. Full article

RNA methyltransferases are key regulators of bacterial physiology, yet their specific roles in virulence remain poorly defined. In this study, we characterize PA3840, a putative RNA methyltransferase in Pseudomonas aeruginosa (P. aeruginosa). Deletion of PA3840 specifically impaired twitching motility without affecting bacterial growth, swimming, or swarming. Notably, PA3840 was found to suppress the expression of Type III Secretion System (T3SS) genes, thereby reducing cytotoxicity and host cell rounding. Consistent with these observations, PA3840 expression attenuated pro-inflammatory cytokine production in epithelial cells by inhibiting NF-κB activation. Mechanistic analysis revealed that PA3840 is translocated into host cells in a Type VI Secretion System (T6SS)-dependent manner. This translocation was reduced by hcp1 deletion and nearly abolished by a double deletion of pscF and hcp3, suggesting the involvement of multiple T6SS components and potential interplay with T3SS machinery. However, direct transfection of PA3840 into host cells failed to suppress cytokine expression, indicating that its immunomodulatory function is mediated by a bacterium-intrinsic mechanism rather than direct intracellular action. Collectively, these findings identify PA3840 as a translocated effector that modulates twitching motility and dampens host inflammation by repressing T3SS and NF-κB signaling, revealing a novel layer of post-transcriptional virulence regulation in P. aeruginosa. Full article

The lactoperoxidase system (LpoS) is an enzymatic antimicrobial mechanism of saliva that oxidizes (pseudo)halide substrates to reactive compounds capable of limiting microbial growth. This study evaluated how different LpoS variants—utilizing iodide (LpoS-I⁻), thiocyanate (LpoS-SCN⁻), selenocyanate (LpoS-SeCN⁻), and a thiocyanate–iodide mixture (LpoS-SCN⁻ + I⁻)—affect virulence, metabolism, and biofilm structure in Streptococcus mutans. Using qRT-PCR, pyruvate assays, MTT reduction, and confocal microscopy, we found that LpoS-I⁻ most effectively reduced atpD and ldh expression, impaired acid tolerance, and decreased lactate and pyruvate production. LpoS-SCN⁻ and LpoS-SeCN⁻ also downregulated atpD and gtfB, although LpoS-SeCN⁻ upregulated ldh. Despite minimal structural biofilm disruption, LpoS-I⁻ markedly inhibited intracellular and extracellular pyruvate accumulation, suggesting altered glycolytic flux. These findings indicate that iodide-based LPO systems modulate key metabolic and regulatory pathways in S. mutans and may hold potential for inclusion in anticaries oral formulations. Full article

Anthropogenic climate change represents a critical and complex threat to the health and resilience of aquatic ecosystems. This review aims to critically synthesise and evaluate the synergetic and antagonistic mechanisms through which rising water temperature, the most prominent climatic factor, modulates the host–parasite relationship. The systematic literature review was conducted across a high-impact database (Web of Science), focusing on the extraction and qualitative analysis of data concerning infection dynamics and both host and parasite interactions. The findings demonstrate that thermal stress imposes a dual penalty on host–parasite systems: (1) it confers a critical thermal advantage to direct-life cycle parasites, significantly accelerating their virulence, reproduction, and infective capacity; (2) simultaneously, it severely compromises the immunocompetence and physiological resilience of piscine hosts, often through immunometabolic trade-offs and inflammatory dysfunction. This toxic synergy is the root cause of the exponential disease prevalence/intensity of parasites and fish mass mortality events, directly impacting biodiversity and global aquaculture sustainability. In contrast, it may also cause the disruption of the transmission chains to threaten complex life cycle parasites with localised extinction. We conclude that climate mitigation must be urgently recognised and implemented as a primary strategy for biological risk management to secure aquatic health and global food safety. Full article

Repeat-in-toxin (RTX) toxins are calcium-dependent exoproteins secreted by diverse Gram-negative bacteria and play central roles in cytotoxicity, immune modulation, and tissue colonization. While their structure and secretion mechanisms are well-characterized, the regulation of RTX toxin expression remains complex and species-specific. This review provides a comprehensive overview of the regulatory networks governing RTX gene expression, highlighting both conserved mechanisms and niche-specific adaptations. RTX genes are controlled by multilayered regulatory systems that integrate global transcriptional control, metabolic regulation, and environmental sensing. Expression is further shaped by host-derived signals, physical contact with host cells, and population-dependent cues. Quorum sensing, post-transcriptional regulation by small RNAs, and post-translational activation mechanisms contribute additional layers of control to ensure precise regulation of toxin production. We also explore how RTX regulation varies across anatomical niches, including the gut, lung, bloodstream, and biofilms, and how it is co-regulated with broader bacterial virulence. Finally, we discuss emerging insights from omics-based approaches and the potential of anti-virulence strategies targeting RTX regulatory pathways. Together, these topics underscore RTX regulation as a model for adaptive virulence control in bacterial pathogens. Full article

Enterovirus D68 (EV-D68), a neurotropic respiratory pathogen, poses a considerable clinical threat through its link to pediatric acute flaccid myelitis (AFM) and severe respiratory illness. The possibility of recurrent epidemics, evidenced since the 2014 outbreak, remains a major concern. Genomic determinants of virulence are central to this threat. Sequence variations that affect host–receptor interactions, immune evasion, and replication efficiency serve as critical modifiers of pathogenicity. This article systematically reviews the evidence for specific genomic sites that enhance EV-D68 virulence, focusing on three critical regions: the VP1 receptor-binding site, the 2Apro/TRAF3 cleavage site, and the 3Cpro immunoregulatory region. Mutations in the VP1 receptor-binding site can alter affinity for host receptors such as sialic acid, heparan sulfate, and MFSD6, thereby shaping viral entry and tissue tropism. Alterations in the 2Apro/TRAF3 cleavage site may impair proteolytic cleavage of host TRAF3, attenuating immune evasion and reducing viral pathogenicity. Variations in the 3Cpro region affect its efficiency in cleaving host proteins involved in translation and autophagy, ultimately modulating viral replication and antiviral responses. Finally, we propose that monitoring for mutations in these key virulence determinants, particularly within the surface-exposed VP1, is essential for effective outbreak preparedness. Full article

Candida albicans is a pathogenic fungus that expresses a fungal NADPH oxidase known as C. albicans Cfl11, which produces reactive oxygen species (ROS). Secretion of these ROS triggers caspase 3–mediated cell death in hepatocytes, which was attenuated in a mutant with a disrupted CaCFL11 gene (designated Cacfl11Δ mutant). Here, we compared the effects of the C. albicans wild-type strain and the Cacfl11Δ mutant. Our findings revealed that C. albicans reduces the viability of HaCaT keratinocytes in a contact-independent manner. Furthermore, exposure to C. albicans increased intracellular ROS production and caspase 3 activity in HaCaT keratinocytes. These changes were attenuated when HaCaT keratinocytes were exposed to the Cacfl11Δ mutant or when HaCaT keratinocytes were treated with the known antioxidant N-acetylcysteine. Furthermore, wild-type C. albicans, but not the Cacfl11Δ mutant, disrupted transepithelial electrical resistance and modulated the downregulation of the tight-junction genes occludin and junction adhesion molecule 1 in HaCaT keratinocytes. Collectively, these results show that fungal ROS secretion via CaCFL11 is a potent virulence factor in mediating keratinocyte viability and barrier function. Full article

Volatile organic compounds produced by microbes are increasingly recognized as modulators of microbial interactions and mediators of both intra- and inter-kingdom communication. This study explored the possible ecophysiological roles of nine amides from Streptomyces sp. NP10 in quorum sensing (QS) and biofilm formation in Pseudomonas aeruginosa PAO1. GC-MS profiling, synthesis, spectral validation, and co-injection experiments confirmed compound identities. Notably, N-(3-methyl-2-butenyl)acetamide is reported as a new natural product and N-(2-methylbutyl)acetamide as a new Streptomyces-produced metabolite. At subinhibitory concentrations (250 μg/mL), most of the amides enhanced P. aeruginosa biofilm formation, with N-(2-methylbutyl)acetamide, N-(3-methyl-2-butenyl)acetamide, and 2-phenylacetamide showing the strongest effects. Simultaneously, these compounds suppressed QS by reducing the production of N-acyl homoserine lactones (AHLs) and 2-alkyl-4-quinolones (AHQs). Aliphatic acetamides preferentially inhibited short-chain AHLs, while N-acetyltyramine and 2-phenylacetamide mainly affected quinolone signaling. These opposing effects on QS and biofilm are consistent with the involvement of alternative regulatory circuits. Motility assays showed biofilm stimulation was not correlated with altered swarming or twitching. Cross-species assays revealed limited QS inhibition, with only N-acetyltryptamine reducing violacein production in Chromobacterium violaceum CV026. Most of the amides were non-cytotoxic at 100 μM (10.5–20.2 μg/mL), except for 2-phenylacetamide. Overall, these amides likely serve as microbial signals influencing QS and biofilm formation, offering leads for anti-virulence strategies. Full article

Bulleidia extructa strain PP_925, isolated from the periodontal pocket of a patient with periodontitis, is a Gram-positive Bacillota with an unusually compact genome of 1.38 Mb. Phylogenomic analyses place PP_925 within Erysipelotrichales and show close relatedness of Bulleidia to Solobacterium and Lactimicrobium, as well as the existence of previously undescribed related clades. The metabolic repertoire of PP_925 is strongly reduced: it retains glycolysis, the phosphotransacetylase–acetate kinase pathway, and arginine catabolism but lacks the tricarboxylic acid cycle and most de novo biosynthetic pathways for amino acids, nucleotides, fatty acids, cofactors, and vitamins, implying reliance on salvage and cross-feeding. Phylogenetic inference indicates independent peptidoglycan losses in multiple mycoplasma Erysipelotrichia-related lineages, while PP_925 has retained an ancestral Gram-positive cell wall despite extensive genomic reduction. The genome preserves systems crucial for host interaction and adaptability, including a horizontally acquired tad locus encoding type IV pili, a comG competence system, and several adherence-associated virulence factors. Defense mechanisms are diverse and include a CRISPR-Cas II-A system, a type II restriction–modification module adjacent to Gao_Qat-like genes, and the Wadjet system in a genome without prophages; CRISPR spacers indicate repeated encounters with Bacillota phages. Comparative genomics of PP_925 and related strains reveals a small core genome with lineage-specific adhesion and defense modules, indicating recent shared ancestry combined with adaptive flexibility under substantial genome reduction. Full article

Objectives: Despite the increasing scientific evidence regarding the application of Cranberries in dentistry, a comprehensive understanding of their potential benefits, active constituents, and mechanisms of action remains lacking. Consequently, this narrative review aims to meticulously analyze and consolidate the existing scientific literature on the utilization of Cranberries for the prevention and treatment of oral diseases. Materials and Methods: Electronic databases (PubMed, Scopus, and Web of Science) were searched up to October 2025. This review included in vitro, in vivo, and clinical research studies. A two-phase selection process was carried out. In phase 1, two reviewers independently screened titles and abstracts to identify potentially eligible studies. In phase 2, the same reviewers performed the full-text assessments of the eligible articles. Results: Among the 93 eligible articles, most assessed Cranberry use in Cariology (n = 28) and Periodontics (n = 26). Biofilm and microbial virulence factors (n = 46) were the most frequently studied topics. Cranberry extract (n = 32) and high-molecular-weight non-dialyzable material (NDM) (n = 23) were the most evaluated Cranberry fractions. Overall, Cranberry-derived compounds were identified as non-toxic and demonstrated promising antimicrobial activity against dental caries-related microorganisms in preclinical studies (n = 20). Regarding periodontal and peri-implant diseases, Cranberry demonstrated host immune modulator effects, counteracting the inflammatory and destructive mechanisms (n = 8). Additionally, Cranberries presented benefits in reducing the inflammation associated with periodontal disease and temporal mandibular joint lesions (n = 1). Regarding dental erosion, Cranberry inhibited dentin erosion (n = 4); however, no effect was observed on enamel lesions (n = 2). As an antioxidant agent, Cranberry showed effectiveness in preventing dental erosion (n = 18). Beyond that, Cranberry neutralized reactive oxygen species generated immediately after dental bleaching, enhancing bond strength (n = 2) and counteracting the oxygen ions formed on the tooth surface following bleaching procedures (n = 3). In osteoclastogenesis assays, A-type proanthocyanidins inhibited bone resorption (n = 1). In osteogenic analysis, preservation of hydroxycarbonate apatite deposition and an increase in early and late osteogenic markers were observed (n = 2). Conclusions: Cranberry bioactive compounds, both individually and synergistically, exhibit substantial potential for diverse applications within dentistry, particularly in the prevention and management of oral and maxillofacial diseases. This review provides insights into the plausible incorporation of Cranberries in contemporary dentistry, offering readers an informed perspective on their potential role. Full article

Biofilms are more than just structural microbial communities. They are dynamic chemical ecosystems that synthesize a range of extracellular compounds involved in functions that extend beyond biofilm architecture. From quorum-sensing molecules like acyl-homoserine lactones (AHLs) to short-chain fatty acids (SCFAs), phenazines, indoles, and reactive sulfur species (RSS), biofilm-derived metabolites can impact the physiology and behavior of microorganisms living in the same ecosystem, including other bacteria and protozoa. It has recently been demonstrated that such molecules may also modulate competition between microbes, promote cooperation, and impact motility, differentiation, or virulence of free-living and parasitic protozoa. This review aims to discuss biofilm compounds that mediate interspecies or interkingdom interactions and their involvement in regulating gut and environmental microbiomes functions, and host–pathogen relationships with special emphasis on protozoan activity and the infection outcome. This review will also address how this chemical dialog can be explored to identify new therapeutic interventions against microbial infections and parasitic diseases. Full article

Candida biofilms play a critical role in clinical settings, contributing to persistent and device-associated infections and conferring resistance to antifungal agents, particularly in immunocompromised or hospitalized patients. Biofilm formation varies among Candida species, including C. albicans and non-albicans species, such as C. glabrata, C. tropicalis, C. parapsilosis, and C. auris, due to species-specific transcriptional networks that regulate modes of biofilm development, extracellular matrix composition, and metabolic reprogramming. These differences influence biofilm responses to treatment and the severity of infections, which can be further complicated in polymicrobial biofilms that modulate colonization and virulence. Understanding the mechanisms driving biofilm formation and interspecies interactions is essential for developing effective therapies and requires appropriate experimental models. Available models range from simplified in vitro systems to more complex ex vivo and in vivo approaches. Static in vitro models remain widely used due to their simplicity and reproducibility, but they poorly mimic physiological conditions and require careful standardization. Ex vivo tissue models offer a balance between practicality and biological relevance, enabling the study of biofilm physiology, host–microbe interactions and immune responses. In vivo models, primarily in mice, remain the gold standard for testing antifungal therapies, while alternative systems such as Galleria mellonella larvae provide simpler, cost-effective approaches. Advanced in vitro platforms, including organ-on-chip systems, bridge the gap between simplified tests and physiological relevance by simulating fluid dynamics, tissue architecture, and immune complexity. This review aims to examine Candida biofilms across species, highlighting differences in structural diversity and clinical implications, and to provide a guide to the most widely used experimental models supporting studies on Candida biofilm biology for the development of new therapeutic targets or drug testing. Full article

Visceral white spot disease caused by Pseudomonas plecoglossicida severely threatens marine aquaculture, highlighting the need for effective control strategies. To clarify the role of a novel small RNA, sRNA0024, in bacterial pathogenicity, we constructed an sRNA0024 deletion mutant (ΔsRNA0024) and compared its phenotype and virulence with those of the wild-type strain NZBD9. In vitro assays showed that deletion of sRNA0024 did not affect bacterial growth but significantly reduced biofilm formation and adhesion. In vivo infection experiments in orange-spotted grouper (Epinephelus coioides) demonstrated that the ΔsRNA0024 mutant had a 3.8-fold higher 50% lethal dose (LD₅₀), improved host survival, and milder splenic lesions than the wild type. Histopathology and host transcriptome analyses revealed weakened activation of complement–coagulation cascades, neutrophil extracellular traps, leukocyte migration, and inflammatory signaling pathways, indicating a lower-intensity immune response. Bacterial transcriptomics showed that deletion of sRNA0024 was associated with reduced luxR expression and attenuated quorum-sensing–associated virulence traits, supporting a possible role for this small RNA in modulating luxR expression and QS-related host immunopathology. These findings identify sRNA0024 as an important contributor to the virulence of P. plecoglossicida and highlight the sRNA0024–luxR module as a potential antivirulence target for controlling visceral white spot disease in aquaculture. Full article