Search Results (2,900)

Phlebotomine sand flies are dipterans that transmit leishmaniasis, bartonellosis, and arboviruses of public health importance. Colombia is a tropical country with high annual incidences of arboviruses, such as dengue and, more recently, yellow fever, all of which have similar symptoms. This study characterized the viruses circulating in phlebotomine sand flies in two departments in the Colombian Caribbean. Between August 2023 and December 2024, a descriptive study was conducted in the Departments of Córdoba and Cesar in Colombia. Four municipalities were selected per department, and four insect captures were performed using CDC light traps. Specimens were taxonomically identified and organized into groups according to species and study area, and total RNA was extracted for NGS analysis. Short sequences were quality-assessed, assembled using MEGAHIT to obtain contigs, and classified using DIAMOND-MEGAN6 to select viral genomic sequences for phylogenetic analysis. Thirteen viral families were identified, including a virus from the family Rhabdoviridae in Pi. evansi in the department of Cesar and another from the family Dicistroviridae in Lutzomyia gomezi in both departments. Two genome segments of the family Phenuiviridae were found in Lutzomyia gomezi in the department of Córdoba, Colombia. Sand flies harbor a diverse range of viral families, some of which are previously undescribed, and can be studied to determine their taxonomy and assess their potential to infect vertebrate cells or their interactions with medically important pathogens such as Leishmania spp. Full article

Background: Fungal ocular infections, including keratitis and endophthalmitis, remain difficult to treat due to limited antifungal efficacy, poor tissue penetration, and biofilm-mediated resistance. This study evaluated the antifungal and host-protective potential of N-(4-methoxycinnamoyl)-anthranilic acid (NMCA) against Candida albicans and the multidrug-resistant Candidozyma auris. Methods: The antifungal activity of NMCA was assessed by analyzing fungal viability over time, ergosterol levels, and its interaction with fluconazole. Its antibiofilm activity was evaluated through biomass and metabolic activity measurements, together with the expression of genes involved in adhesion (ALS3, ALS5, HWP1) and membrane homeostasis (ERG11, OLE1). In addition, infected epithelial models were used to investigate epithelial damage, intracellular fungal burden, oxidative stress, and wound closure. Results: NMCA showed promising antifungal activity (MIC80 75 μg mL⁻¹ against C. albicans and 100 µg mL⁻¹ against C. auris), inducing a time-dependent reduction in fungal viability of about 4-log10 after 24 h. The compound also reduced ergosterol levels and showed synergistic interaction with fluconazole, as indicated by FICI values of 0.203 for C. albicans and 0.375 for C. auris. Moreover, NMCA markedly inhibited biofilm formation by reducing both biomass and metabolic activity up to approximately 80%, while modulating the expression of key adhesion- and membrane-related genes. Beyond its direct antifungal effects, NMCA reduced epithelial damage and intracellular fungal burden, attenuated oxidative stress, and significantly improved wound closure (reaching 76.26% and 90.46% closure in C. albicans- and C. auris-infected cells, respectively) in infected epithelial models. Conclusions: Although limited by the use of in vitro systems, these findings highlight the multifunctional profile of NMCA, which combines antifungal, antibiofilm, and tissue-protective activities. By simultaneously targeting pathogen viability, biofilm formation, and host cell integrity, NMCA appears to be a promising adjunctive candidate for the treatment of ocular fungal infections, where both pathogen eradication and tissue preservation are crucial for clinical outcomes. Full article

Avian influenza virus (AIV), a zoonotic pathogen capable of cross-species transmission, poses a significant global health threat due to its rapid evolutionary adaptation. This review consolidates evidence from the past decade on AIV-autophagy interactions, emphasizing mechanistic insights and therapeutic potential. Research indicates that various AIV strains can trigger autophagosome formation via viral components, although the completeness of autophagic flux is not fully understood. These virus–host interactions are notably influenced by viral genotypes (e.g., H5N1 vs. H9N2) and host species (avian vs. mammalian). Current studies suggest that modulating autophagy may reduce AIV-induced acute lung injury, with pharmacological agents showing potential in mitigating inflammatory responses. We systematically explore three research areas: (1) strain-specific mechanisms of autophagy induction, (2) host-specific autophagic responses in poultry and human models, and (3) the therapeutic potential of stage-specific autophagy manipulation. This synthesis clarifies critical knowledge gaps, particularly the need for standardized autophagic flux assessment in avian cells, while providing a conceptual framework for developing autophagy-targeted strategies against AIV pathogenesis. Full article

The Lysobacter capsici XL1 β-lytic protease (Blp) is a bacteriolytic enzyme that hydrolyzes peptide bonds in the interpeptide bridge of the peptidoglycan of Gram-positive bacteria, including antibiotic-resistant strains of pathogenic bacteria. The Blp has been extensively characterized. The only unexplored aspect is the mechanism by which this enzyme recognizes target cells. In this work, we demonstrated for the first time that the Blp structure contained a C-terminal subdomain that can be responsible for this interaction. Molecular modeling suggested a hydrophobic nature of the interaction between the Blp and peptidoglycan. Model mutant forms of the Blp, which have fewer hydrophobic areas in the C-terminal subdomain, also had fewer sites for potential interaction with the ligand. Wet lab experiments showed that these mutant Blp forms exhibited poorer binding to peptidoglycan and living Staphylococcus aureus 209P cells, resulting in decreased bacteriolytic and proteolytic activity. Amino acid residues N136 and Y160 in the C-terminal subdomain were identified and can be important for the interaction of the enzyme with target cells. Further research into the mechanism of target cell recognition by bacterial bacteriolytic proteases will enable the use of this knowledge to expand the specificity of action of these enzymes, including as antimicrobial agents for medical applications. Full article

The β-1,3-glucanase gene family plays an important role in fungal cell wall degradation and is closely associated with the mycoparasitic interactions of biocontrol fungi. In this study, the β-1,3-glucanase gene family was identified in the mycoparasitic Alternaria alternata strain KMR13, and its expression patterns under Podosphaera pannosa spore induction were analyzed to investigate the role of the gene Aag25 in the degradation of P. pannosa spores. The β-1,3-glucanase gene was extracted from the genome using the bioinformatics method. According to the expression level of spore-induced genes of P. pannosa, the GH17 family genes that may be involved in mycoparasitism were screened, cloned, and expressed. The expressed protein was purified, and its activity and ability to destroy spores of P. pannosa were determined. A total of 30 β-1,3-glucanase genes were identified in strain KMR13, including 18 members of the GH16 family, 8 of the GH17 family, and 2 genes each from the GH64 and GH81 families. Transcriptome analysis revealed that 23 of these genes were expressed under spore induction. Based on differential expression analysis, the β-1,3-glucanase gene Aag25 was selected for prokaryotic expression. The recombinant Aag25 protein (~32.08 kDa) was successfully induced and purified, exhibiting an enzymatic activity of 1.464 U/mg protein. Functional assays demonstrated that recombinant Aag25 could effectively disrupt the cell walls of P. pannosa spores, leading to spore rupture and cytoplasmic leakage. These results indicate that Aag25 plays an important role in fungal cell wall degradation during the mycoparasitic process of strain KMR13 and provides a potential enzymatic resource for the development of biological control strategies targeting fungal pathogens. Full article

Background: Helicobacter pylori is a globally prevalent gastric pathogen associated with chronic gastritis, peptic ulcer disease, and gastric adenocarcinoma. Its persistence within the gastric niche is strongly linked to biofilm formation, contributing to immune evasion and antibiotic therapy resistance. Methodology: In the present study, we investigated the antibiofilm potential of capsaicin, a natural phytochemical derived from Capsicum species, against H. pylori using experimental and computational approaches. Results: Capsaicin treatment significantly reduced biofilm biomass (up to 75.66 ± 4.00%), metabolic activity (up to 61.23 ± 6.88%), and cell surface hydrophobicity in a dose-dependent manner. Microscopic analyses revealed disrupted biofilm architecture and diminished extracellular polymeric substance at higher concentrations. Molecular docking analysis revealed that capsaicin interacts with target H. pylori proteins (GTP cyclohydrolase II, α-carbonic anhydrase, and urease) through stable hydrogen bonds and hydrophobic contacts. Molecular dynamics simulations further supported the stability of these complexes and demonstrated reduced structural fluctuations upon ligand binding. Free energy landscape analysis suggested ligand-induced conformational alterations in α-carbonic anhydrase, indicating possible structural effects associated with capsaicin interaction. Conclusions: Overall, the findings provide insight into the antibiofilm activity of capsaicin against H. pylori and highlight its potential as a natural adjunct strategy for combating biofilm-associated persistence and antimicrobial resistance. Full article

Metabolic dysregulation is increasingly recognized as a central feature linking chronic infection, immune dysfunction, and skeletal deterioration; however, these processes are most often investigated in isolation, limiting the development of integrative mechanistic frameworks. In this review, we propose the Metabolic Reprogramming Interface Model (MRIM) as a systems-level, hypothesis-generating construct that conceptualizes metabolism as a shared regulatory axis bridging host–pathogen interactions and bone microenvironment remodeling. Importantly, MRIM is not presented as a unified or experimentally validated disease model, but rather as a structured framework designed to organize and critically evaluate emerging multidisciplinary evidence. At the molecular level, metformin, a widely used metabolic modulator, has been shown to influence mitochondrial bioenergetics, AMP-activated protein kinase (AMPK) signaling, redox balance, and autophagic pathways, all of which are independently implicated in microbial persistence, immune cell function, and skeletal homeostasis. Within MRIM, these observations are integrated to hypothesize that metabolic perturbation may coordinately influence infection dynamics, inflammatory responses, and bone turnover. Nevertheless, most of the supporting evidence remains indirect, arising from in vitro studies, animal models, and observational clinical datasets, thereby limiting causal inference. To address this, the framework explicitly distinguishes between experimentally validated mechanisms, context-dependent biological interactions, and higher-order theoretical integrations. While preliminary findings suggest that metformin may modulate microbial fitness, attenuate excessive inflammation, and influence bone remodeling, these effects appear to be highly context-dependent and have not yet been substantiated in adequately powered prospective clinical trials evaluating combined infectious and skeletal outcomes. This review therefore provides a critical synthesis of current knowledge, highlights key mechanistic and translational uncertainties, and outlines testable hypotheses for future investigation, positioning MRIM as a conceptual scaffold to guide interdisciplinary research rather than a definitive explanatory model. Full article

Extracellular vesicles (EVs) have emerged as key mediators of intercellular communication in the brain, with glial cell-derived EVs increasingly recognized for their roles in maintaining brain homeostasis and contributing to the progression of neurodegenerative diseases. By transferring a diverse cargo of bioactive molecules, including proteins, RNAs, and organelles, EVs influence recipient cell behavior and overall brain function. In neurodegenerative conditions, glial EVs can either propagate pathogenic signals or deliver neuroprotective and regenerative cues, depending on their cellular origin and molecular composition. This context-dependent heterogeneity highlights the need for physiologically relevant human models to investigate EVs biology. Human induced pluripotent stem cell (iPSC)-derived glial models provide a disease-relevant platform, as they recapitulate key pathological features of Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). When further integrated with brain organoid platforms, these iPSC-based systems enable the generation of three-dimensional environments that closely resemble in vivo EVs dynamics. Importantly, glial EVs can modulate cellular pathways involved in neuronal survival and function. Indeed, their potential to interact with and, under specific experimental conditions, traverse the blood–brain barrier (BBB) has contributed to growing interest in their application for biomarker discovery and therapeutic development. Engineered and patient-specific EVs derived from iPSCs are emerging as promising tools for targeted, cell type-specific, therapeutic approaches, although their clinical applicability still requires further validation. This review discusses the emerging evidence supporting the dual role of iPSC-derived glial EVs in health and disease, underscores the translational potential of iPSC-based platforms for mechanistic studies, and outlines their promise as precision medicine tools for diagnostics and therapy. Full article

Heat shock proteins (HSPs) are highly conserved molecular chaperones that play a key role in maintaining protein homeostasis and cellular survival under stress conditions. Clinically relevant human pathogenic fungi include opportunistic fungi, dimorphic fungi, dermatophytes, Mucorales, and other pathogenic groups. HSPs, including Hsp90, Hsp70, Hsp60, Hsp40, and Hsp110, are essential for the correct nascent protein folding, aggregation prevention, and degradation of misfolded polypeptides. Fungal pathogens frequently encounter environmental and host-imposed stresses, including oxidative stress, temperature fluctuations, and antifungal treatments. This review synthesizes and critically analyzes current evidence on the role of HSP families in essential processes linked to fungal virulence, including morphogenetic transitions, biofilm formation, maintenance of cell wall integrity, and interactions with host immune cells. Beyond their canonical chaperone functions, HSPs act as central mediators in pathogenic processes, such as morphogenesis transitions, biofilm formation, cell wall integrity, and interactions with host immune cells. Hsp90 stabilizes key signaling proteins involved in stress responses, morphogenesis, and antifungal resistance, while Hsp60 and Hsp70 contribute to mitochondrial function, cell wall integrity, and immune modulation. Disruption of these chaperones impairs growth, reduces virulence, and increases susceptibility to antifungal agents. The rise of antifungal resistance underscores the urgent need for new therapeutic strategies. Targeting fungal HSPs has emerged as a promising approach due to their essential roles in stress tolerance and pathogenesis. Hsp90 inhibitors, including geldanamycin derivatives and other small molecules, have demonstrated the ability to impair fungal growth, reduce virulence traits, and sensitize resistant strains to conventional antifungal drugs. Combining HSP inhibitors with existing antifungal drugs represents a potential strategy to overcome resistance and improve treatment outcomes. This review summarizes the current knowledge on HSPs in pathogenic fungi, focusing on their roles in stress adaptation, virulence, host-pathogen interaction, antifungal resistance, and their potential as targets for novel antifungal therapies. Full article

Neospora caninum is a major apicomplexan pathogen responsible for significant reproductive losses in livestock, yet lacks effective therapeutics. Here, we identify and functionally characterize a previously unstudied OTU-like deubiquitinase (ncOTU; XP_003886403) as a key modulator of host–pathogen interactions. Sequence and structural analyses revealed conservation of the catalytic triad (D257, C260, H362) and a Y305-W315-G316 inhibition pocket analogous to viral OTU proteases. Recombinant ncOTU exhibited robust deubiquitinase activity and significantly reduced global ubiquitination levels in mammalian cells, preferentially targeting mono-ubiquitinated and low-molecular-weight substrates. Transcriptomic analysis demonstrated that ncOTU expression correlates with suppressed NF-κB signaling, type I interferon responses, and downstream antiviral effectors, while partially uncoupling upstream nucleic acid sensing pathways. Structure-based virtual screening and biochemical validation identified multiple small-molecule inhibitors targeting the conserved inhibition pocket. Dose-response analysis revealed submicromolar potency for ncOTUi-9 (IC₅₀ = 0.1 μM), ncOTUi-8 (0.2 μM), and ncOTUi-19 (0.3 μM), whereas ncOTUi-3 showed lower activity (7.1 μM). Interaction analyses confirmed stable binding within the inhibition pocket, with more extensive contact networks correlating with increased potency. Collectively, these findings establish ncOTU as a functional deubiquitinase that contributes to evasion and highlight it as a promising therapeutic target for neosporosis. Full article

Staphylococcus aureus is a major cause of foodborne intoxication through the production of heat-stable enterotoxins (SEs) and is also an important opportunistic pathogen of humans and livestock. Meat and meat products are major vehicles for this pathogen because their protein-rich composition supports bacterial growth and toxin production. However, the combined effects of temperature and nutrient composition on S. aureus growth and virulence expression under food-relevant conditions remain unclear. In this study, we investigated the interactive effects of temperature and nutritional context on the growth and virulence-associated phenotypes under model food-relevant environments with the reference strain S. aureus FRI-S6. Bacterial growth, biofilm formation, staphylococcal enterotoxins A and B (SEA, SEB), and hemolytic activity were evaluated at 25 °C and 37 °C in brain heart infusion (BHI) medium supplemented with NaCl, glucose, or tryptone to simulate diverse food-relevant conditions. Growth was generally faster at 37 °C, whereas glucose-supplemented cultures at 25 °C reached higher cell densities during prolonged incubation. Biofilm formation increased at 37 °C in BHI and glucose conditions. SEA production was enhanced at 37 °C under NaCl and tryptone, but at 25 °C in glucose-rich conditions. In contrast, SEB production and hemolytic activity were consistently higher at 37 °C, particularly in the presence of tryptone and glucose. These findings demonstrate the strong interaction between temperature and nutrient composition in shaping S. aureus virulence in food environments and provide important insights for food safety risk assessment and highlight practical implications for controlling enterotoxin production in meat products and other foods during storage and processing. Full article

O-linked glycosylation comprises distinct regulatory systems, including secretory-pathway mucin-type O-GalNAc glycosylation and intracellular O-GlcNAcylation. These modifications both target serine/threonine residues but differ in glycan structure, cellular compartment, enzymatic machinery, and biological function. This narrative review was based on targeted searches of PubMed, Web of Science, and related literature using keywords related to O-glycosylation, O-GalNAc glycosylation, O-GlcNAcylation, immune regulation, cell signaling, glycoproteomics, and congenital disorders of glycosylation (CDG). We summarize evidence that mucin-type O-glycosylation regulates receptor behavior, cell adhesion, immune checkpoints, immunoglobulin function, antigen recognition, and pathogen–host interactions, whereas O-GlcNAcylation mainly modulates intracellular signaling, transcriptional control, stress responses, post-translational modification crosstalk, and innate immune pathways. We also discuss how glycosylation defects, including CDG and selected O-linked glycosylation disorders, connect genetic variation with disease phenotypes. Recent advances in site-specific glycoproteomics, O-glycoprotease-assisted workflows, LC–MS/MS-based glycopeptide analysis, and spatial or temporal profiling have improved mechanistic interpretation but still face limitations in site localization, structural resolution, and functional validation. Overall, the evidence supports the hypothesis that distinct O-linked glycosylation systems act through different molecular mechanisms but converge on signaling regulation, immune homeostasis, and disease susceptibility. Full article

Hantaviruses are emerging zoonotic pathogens responsible for two severe clinical syndromes: (i) haemorrhagic fever with renal syndrome (HFRS) and (ii) hantavirus cardiopulmonary syndrome (HCPS), collectively causing more than 200,000 human cases annually worldwide. Despite their public-health importance, the molecular mechanisms governing the host response and the population-level dynamics of rodent-to-human spillover remain incompletely characterised. The timeliness of this framework is underscored by the April–May 2026 outbreak of Andes orthohantavirus aboard the MV Hondius cruise ship, the first such cluster in a maritime setting, with three deaths reported across multiple countries. This event revealed critical gaps in existing models that treat humans solely as dead-end spillover hosts. Our coupled Susceptible-Exposed-Infectious-Recovered-Dead (SEIRD) model assumes no human-to-human transmission and is therefore designed for hantavirus strains where spillover does not lead to secondary human cases, specifically Hantaan virus (HTNV), Puumala virus (PUUV), Sin Nombre virus (SNV), and Dobrava-Belgrade virus (DOBV). The Andes virus (ANDV) outbreak aboard the MV Hondius is used as a real-world case study to assess the boundaries of our model and to motivate future extensions, not as a direct validation target for its quantitative predictions. Here, we present an integrated computational study combining three complementary analyses. First, we performed a preliminary phylogenetic analysis of the viral sequence, identifying Orthohantavirus andesense as the likely etiological agent responsible for the vessel-associated outbreak. Second, we carried out a downstream transcriptomic analysis of Hantaan virus (HTNV)-infected human umbilical vein endothelial cells (HUVECs), using publicly available RNA-seq data (GEO accession GSE133751, $n=3$ per group). This analysis identified 184 upregulated and 19 downregulated genes, highlighting a transcriptional response dominated by interferon-stimulated genes (ISGs), including CXCL10, CXCL11, MX2, DDX58, IRF7, STAT1, OASL, and CMPK2. We then constructed a protein–protein interaction (PPI) network using STRING, comprising 176 nodes and 3210 edges, and applied a composite network centrality score to rank putative regulatory hubs. This analysis identified ISG15, IRF1, CXCL10, STAT1, and DDX58 as the most central nodes. Pathway enrichment analysis confirmed a strong activation of interferon signalling (Reactome, $p=1.3\times {10}^{-63}$), antiviral defence mechanisms (Gene Ontology, $p=3.8\times {10}^{-58}$), and NF-$\kappa$B-related pathways, together with a concurrent suppression of ribosomal translation. Finally, we developed a coupled SEIRD epidemiological model that explicitly represents rodent-to-rodent and rodent-to-human transmission with logistic rodent population growth. Preliminary simulation analysis demonstrates that reducing human exposure to rodent excreta is substantially more effective than rodent population control alone for reducing human disease burden, and that rodent control in isolation can paradoxically increase human cases through a dilution-like effect. The integrated framework provides molecular and epidemiological insights relevant to hantavirus surveillance, therapeutic target identification, and public-health intervention design. Full article

Nosema bombycis, the causal agent of silkworm pébrine disease, causes substantial economic losses to sericulturists annually. Previously, 19 serpin genes (NbSPNs) were identified in this parasite, but most of their functions remain unidentified yet. Here, we provide a functional and cellular characterization of NbSPN4 and NbSPN5. Bioinformatics tools predicted four cis-regulatory motifs in the promoter region of NbSPN genes. A yeast signal sequence trap (YSST) assay confirmed the computationally predicted N-terminal signal peptide for NbSPN4 but not for NbSPN5. Immunofluorescence assay revealed that NbSPN4 was localized to the nucleus and NbSPN5 to the cytoplasm of infected host BmE cells. Recombinant NbSPN4/5 proteins significantly inhibited host hemolymph melanization and phenoloxidase activity in vitro, demonstrating their immune-regulatory roles. These findings provide essential insights into the roles of NbSPNs in host–pathogen interactions during N. bombycis infection. Full article

Babesia microti is the primary agent of human babesiosis, an emerging tick-borne disease with limited treatment options and growing evidence of drug resistance. Deubiquitinases (DUBs) play critical roles in protein homeostasis and host–pathogen interactions, yet none have been characterized in B. microti. Here, we report the first molecular cloning, expression, and functional characterization of an OTU-like cysteine protease from B. microti (bm-OTU). The recombinant bm-OTU protein (~22 kDa) was expressed in E. coli, purified to high homogeneity, and exhibited ~93% solubility under native conditions. In vitro fluorogenic assays confirmed its deubiquitinase activity. Expression of bm-OTU in HEK293T cells was associated with reduced ubiquitination in cells and increased apoptosis in this overexpression model, as demonstrated by flow cytometry and Western blot analyses. Furthermore, transcriptomic analysis revealed that bm-OTU modulates host immune pathways, notably suppressing the expression of interferon-stimulated genes (APOBEC3G, G1P2) while upregulating the pro-apoptotic gene BAK and the inflammasome sensor AIM2. These findings establish bm-OTU as a functional deubiquitinase and a potential virulence factor that may contribute to immune evasion and pathogenesis in babesiosis and may represent a potential target, pending further validation. Full article