Search Results (894)

Modern wound care is challenged by the emergence of antibiotic-resistant bacterial strains, causing the need for advanced dressing materials that provide infection control while promoting healing. Although polyacrylamide (PAAm) hydrogels are widely investigated due to their biocompatibility, their lack of intrinsic antibacterial activity and poor mechanical properties restrict their clinical use. To overcome these limitations, this study proposes a natural–synthetic hydrogel that combines PAAm with TEMPO-oxidized cellulose nanofiber (TOCNF) functionalized silver nanoparticles (AgNPs). The synthesis is performed through the polymerization of the synthetic monomer in the presence of the TOCNF–AgNPs, the nanofibrillar cellulose simultaneously serving as a reducing and stabilizing agent for AgNPs, and as a plasticizer for the PAAm network. Morpho-structural analysis of the hybrid precursor (TOCNF–AgNPs) revealed two populations of AgNPs, offering a cumulative effect between rapid bacterial penetration and a prolonged ionic reservoir, while maintaining the stability of the system. The subsequent incorporation of the hybrid into PAAm matrix resulted in tunable swelling kinetics and mechanical properties. Wettability and surface stiffness improve with the increase in hybrid content. The antibacterial effect was confirmed by a colony-counting assay for formulations with higher AgNPs content, exhibiting inhibitory metabolic activity against several pathogenic strains. These results suggest that PAAm/TOCNF–AgNPs (PTA) nanocomposites represent a promising mechanically adaptive candidate for wound-care applications. Full article

Candida albicans-associated denture stomatitis is a common inflammatory condition in denture wearers. Conventional tissue conditioners provide temporary relief but lack intrinsic antifungal activity, allowing persistent microbial colonization and biofilm formation. Functionalization with bioactive agents represents a promising preventive strategy. This study evaluated the antifungal efficacy and biocompatibility of pterostilbene (PTE), a natural stilbenoid compound, incorporated into a commercially available tissue conditioner. Antifungal activity of PTE against C. albicans ATCC 10231 was evaluated using broth microdilution and XTT biofilm assays. Tissue conditioner discs containing 1% and 2.5% (w/w) PTE were fabricated and tested after 24 h, 72 h, and 1 week using colony-forming unit (CFU) counts and metabolic activity assays. Biocompatibility was assessed by exposing mouse embryonic fibroblast (MEF) cells to conditioned eluates followed by an MTT viability assay. PTE inhibited biofilm formation in a concentration-dependent manner, with significant suppression observed at ≥8 µg/mL (p < 0.001). A time-dependent antifungal effect was observed over one week. PTE-functionalized tissue conditioners significantly reduced fungal adhesion compared with controls at all-time points (p < 0.001). Cell viability remained above 70%, meeting ISO 10993-5 criteria for non-cytotoxicity, indicating potential for localized prevention of denture stomatitis. Full article

Background: A compact, in-house-developed ultraviolet germicidal irradiation (UVGI) system using eight 36 W Philips low-pressure mercury UV-C lamps with a peak emission at 253.7 nm was developed for effective sterilization of bacteria and fungi using a wireless mode of operation. Methods: Under controlled laboratory conditions, the system was tested against representative biofilm-forming microorganisms, including Bacillus subtilis, Escherichia coli K12, and a multidrug-resistant Candida albicans M-207 isolate. Microbial viability was assessed using colony-forming unit (CFU) enumeration and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with structural changes analyzed by scanning electron microscopy (SEM). Cultures were exposed to 253.7 nm UV-C radiation at distances of 1–5 m for 15–90 min. Results: UV-C exposure resulted in time- and distance-dependent reductions in viable counts for all tested organisms, as determined by CFU analysis. At 1 m and 15 min exposure, viable counts for all tested organisms were reduced below the limit of detection (LOD) of the CFU assay, indicating substantial microbial inactivation under the tested conditions. Reduced efficacy was observed at increased distances (3 m and 5 m), with log₁₀ reductions varying depending on organism and exposure conditions. Residual metabolic activity detected by the MTT assay suggests the presence of non-proliferating or damaged cells, consistent with the different endpoints measured by the two assays. The SEM analysis further revealed disruption of biofilm architecture and reduction in cell density with increasing UV dose. Conclusions: The UVGI system demonstrated dose-dependent inactivation of biofilm-forming microorganisms under controlled conditions, supporting its proof-of-concept efficacy. Further studies are required to evaluate performance under real-world conditions. Full article

The ability to rapidly estimate bacterial numbers in a pure culture is an important research tool, often performed by measuring the optical density of the culture. However, this method is of limited use with mycoplasma cultures. Therefore, a new method for estimating Mycoplasma gallisepticum cell numbers in a pure culture was developed based on the fluorescent measurement of genomic DNA from lysed cells. Actual Mycoplasma gallisepticum counts obtained from either Color Change Units (CCU) or Colony Forming Units (CFU) were used to create equations to estimate mycoplasma concentration from either DNA concentration data obtained from lysed cells or optical density data from mycoplasma in media. The results suggest that calculated counts are slightly more accurate than those obtained from OD600 data. The results further show that calculating culture concentration using the DNA concentration has a wider range compared to using OD600 data. Results also showed that equations generated using one M. gallisepticum strain could work for a second M. gallisepticum strain. However, it was also shown that the equations were not accurate for a different mycoplasma strain. These results suggest that measuring DNA concentration from lysed mycoplasma cells can provide another useful tool for estimating mycoplasma culture concentrations. Full article

Biosurfactant production by hydrocarbon-degrading bacteria is strongly influenced by the nature and concentration of available carbon substrates, which determine hydrocarbon bioavailability and microbial metabolic responses. In this study, five Bacillus subtilis strains isolated from weathered oil-contaminated sites in Qatar were evaluated for growth and biosurfactant activity using diesel fuel, fresh corn oil, and five-times-overheated corn oil as sole carbon sources. Cultures were grown in mineral salts medium under controlled conditions, and biosurfactant production was assessed through emulsification activity (EA), solubilization activity (SA), and colony-forming unit counts. All strains grew on the tested substrates but exhibited distinct strain-specific responses. Fresh corn oil supported the highest biomass production with values up to 3.3 × 10⁷ CFU mL⁻¹, whereas the strongest emulsification activity yield was observed in diesel cultures at low carbon loading (59 ± 2.3 EU g⁻¹ carbon. Five-times-overheated corn oil maintained more stable emulsification activity across a broader concentration range, indicating tolerance to oxidized hydrocarbons and adaptation to chemically altered substrates. Increasing hydrocarbon concentrations led to progressive declines in EA and SA, indicating inhibitory effects at high substrate loads. Overall, biosurfactant production did not correlate directly with biomass, highlighting the importance of substrate properties in regulating functional output. These findings demonstrate that substrate composition and concentration are key determinants of biosurfactant performance in B. subtilis isolates and support the potential use of waste oils as low-cost feedstocks for biotechnological and bioremediation applications. Full article

Honey bees are essential pollinators and ecological indicators, yet conventional monitoring approaches remain labor-intensive and limit the assessment of colony dynamics across biologically relevant time scales. Hive entrance activity, defined as the movement of bees entering and leaving the hive, serves as a direct proxy for foraging effort, resource availability, and colony condition. However, manual observation is restricted in duration and resolution, constraining continuous evaluation of colony responses to environmental change. In this study, a non-invasive automated monitoring framework was developed to quantify hive entrance activity under diverse environmental conditions. The system integrates image-based detection, multi-object tracking, and direction-aware trajectory analysis to identify and quantify incoming and outgoing bees. Trained on 12,013 annotated images representing varied lighting conditions, backgrounds, and activity levels, the framework achieved high detection accuracy (mAP@50 = 0.96–0.98) and real-time processing capability. Video-based evaluations showed that frame-level detections can be translated into entrance and exit estimates, although counting accuracy varied with traffic density and occlusion. These findings demonstrate that automated monitoring enables continuous measurement of biologically meaningful indicators of colony dynamics. The proposed approach provides a scalable tool for investigating foraging activity, seasonal patterns, and colony responses to environmental stressors, supporting improved ecological assessment and pollinator conservation. Full article

Background: Glioblastoma (GBM) is characterized by high morbidity and mortality due to its localization and often locally invasive growth. Current treatment options for GBM are limited, with conventional therapies achieving a median survival of only 15 months. Mechanotherapy has been proposed as a new therapeutic strategy in oncology. Low-intensity focused ultrasound (LIFU), a form of mechanotherapy, has demonstrated inhibitory effects on GBM. However, its underlying mechanisms remain poorly understood. The present study aimed to evaluate the therapeutic effects of LIFU on GBM and investigate its mechanisms of action. Methods: Cell viability and proliferation were evaluated using cell counting kit-8, EdU and colony formation assays, while the effects of LIFU on GBM cell apoptosis were evaluated by flow cytometry. Transcriptome sequencing, immunofluorescence, reverse transcription-quantitative polymerase chain reaction, Western blot, bioinformatics analysis, dual-luciferase reporter assay and chromatin immunoprecipitation were used to investigate the molecular mechanisms underlying the effects of LIFU on GBM. The therapeutic efficacy of LIFU was further validated in a subcutaneous xenograft tumor model, in which tumor size, survival rate and immunohistochemical changes were monitored. Results: The results of the present study demonstrated that LIFU exerts anti-GBM effects by activating Piezo1 and modulating the downstream ATF3/PPP1r15a pathway to regulate apoptosis. LIFU therapy holds promise as a new treatment strategy for GBM, with the potential to improve patient prognosis. Conclusions: LIFU suppresses GBM progression through the Piezo1/ATF3/PPP1r15a axis by activating endoplasmic reticulum stress. Full article

Freshwater scarcity is a major global issue faced by various regions, and the most common portable water sources globally are estuaries, canals, dams, lakes, and rivers. Existing water resources function as the best sinks for the frequent release of effluents from industrial and residential activities. This common practice often results in water pollution, a deterioration in marine biodiversity, and possible health risks for human populations. This study employed standard analytical methods in assessing the physicochemical and microbial characteristics of water samples collected from the Sundays River estuary in Eastern Cape Province (ECP), South Africa (SA). Microbiological assessment revealed that during the spring season, presumptive Escherichia coli (E. coli) colony counts were 1 cfu/100 mL, while total coliforms (TCs) and fecal coliforms (FCs) were recorded at 42.67 cfu/100 mL and 1 cfu/100 mL, respectively. In the summer season, fecal coliform (FC) counts reached 3.5 cfu/100 mL, while Enterococcus levels were higher, ranging up to 77.75 cfu/100 mL. Furthermore, the average standards of physicochemical parameters assessed in water obtained from both spring and summer seasons ranged as follows: pH (8.71–9.31), temperature (20.98–22.21 °C), turbidity (10–35.55 FNU), total alkalinity (22.25–94.00 mg/L), oxidation–reduction potential (ORP) (8.05–151.6 mV), electrical conductivity (EC) (13,915–40,260 uS/cm), salinity (8.07–25.78 psu), dissolved oxygen (DO) (6.79–7.39 mg/L), total dissolved solids (TDSs) (6960.6–20,125 mg/L), and biochemical oxygen demand (BOD) (0.11–2.94 mg/L). The levels of TDS, EC, turbidity, and salinity in the Sundays River estuary water exceeded the World Health Organization (WHO) guidelines of 2017, rendering the water unfit for even recreational purposes. Additionally, the bacterial levels identified in this study were above the values set by the South Africa Department of Water Affairs (SA-DWAF). The identified microorganisms are perceived as essential indicators of fecal contamination and have the potential to multiply in the environment. Possible pollution may be a result of various municipal effluents consistently discharged into the waterbody. Full article

Background: Cataract is a progressive lens opacity. According to the World Health Organization, about 45 million people in the world are blind, with about half of these cases attributable to cataracts. Due to the complexity of cataract disease, current research on cataracts is far from sufficient, so it is especially important to understand the development process and the pathogenic factors of cataracts. Myodes rufocanus (M. rufocanus) is an animal of the M. rufocanus of the hamster family Volinae. In developing M. rufocanus, we found an individual of M. rufocanus with a congenital cataract phenotype. We confirmed the symptoms of cataract under natural light and using a slit lamp. Methods: Therefore, we analyzed the mechanism of congenital cataract in M. rufocanus from the aspects of pathological histology, physiology and biochemistry, and gene level, aiming to explore the feasibility of its development into an animal model of cataract. Cataract is a progressive lens opacity and a leading cause of visual impairment. Understanding its pathogenesis requires appropriate animal models. In a laboratory-bred colony of M. rufocanus, we identified individuals with a spontaneous congenital cataract phenotype, confirmed by gross observation and slit lamp examination. To characterize this phenotype and explore its potential as an animal model, we performed pathological, physiological, biochemical, and transcriptomic analyses using three cataract-affected and three normal age-matched male individuals (8 weeks old per group). Results: Blood tests revealed significantly lower white blood cell and lymphocyte counts in the cataract group, while blood glucose and other biochemical parameters showed no significant differences. Histologically, cataractous lenses exhibited eosinophilic aggregation in the nuclear region with disorganized fiber cells. Transcriptome analysis identified 6544 differentially expressed genes, including downregulation of crystallin genes (CRYBB2, CRYBA4, CRYGS) known to be associated with congenital cataract. KEGG pathway enrichment analysis highlighted retinol metabolism, tyrosine metabolism, and cytochrome P450-related pathways. RT-qPCR confirmed reduced CRYBB2 expression in cataractous eyes. Conclusions: This study provides the first transcriptome dataset for M. rufocanus ocular tissues and offers preliminary evidence that this naturally occurring cataract phenotype may serve as a potential model for congenital cataract research. Full article

Pulsed electromagnetic fields (PEMFs) may exert antimicrobial effects, which could be relevant both in medical applications and as a contributing factor in electro-disinfection processes. This study was designed to evaluate their impact on the viability of Pseudomonas aeruginosa (ATCC 27853). Experiments were performed in three independent biological replicates, each with three technical replicates per group. Groups 1–3 served as controls and were not exposed to PEMFs. Groups 4–6, 7–9, and 10–12 were exposed to PEMFs of 40, 60, and 80 µT, respectively, for 4, 8, and 24 h using a cylindrical copper solenoid coil. Bacterial viability was assessed via colony-forming unit (CFU) counts, and log₁₀ CFU/mL values were reported. Transmission electron microscopy (TEM) was used to examine structural changes in bacterial cells. PEMF exposure significantly reduced P. aeruginosa viability, with magnetic field strength (p < 0.001), exposure time (p < 0.01), and their interaction (p < 0.05) showing significant effects. Post hoc analysis revealed that higher field strengths, particularly 80 µT after 24 h, produced the greatest reduction in CFU counts, whereas 40 µT showed no significant difference compared to controls (p > 0.05). TEM images demonstrated pronounced degeneration and structural damage in PEMF-exposed bacterial cells. PEMF exposure reduced CFU counts in an intensity and duration-dependent manner. While a dose-related trend is suggested, limited experimental conditions preclude definitive conclusions, and findings should be interpreted cautiously due to the in vitro design. Full article

Titanium alloys are widely used in dental implants due to their excellent mechanical properties. However, their inertness and poor antibacterial activity cause interfacial loosening and failure, shortening service life. This study integrates surface microtexturing with coating technologies, employing modified light-curing composite resins to boost the bioactivity of medical titanium alloys via surface modification. The results reveal that surface microtexturing enlarges the coating-substrate contact area by 42.5% compared with rough surfaces, concurrently diminishing stress per unit area, and the coating on microtextured Ti-6Al-4V (TC4) surfaces achieves adhesion with a damaged area of only 0.5%, thereby notably enhancing adhesion between the coating and TC4 matrix. In comparison, with rough surfaces (surface roughness of 0.658 μm), smooth TC4 planes (surface roughness of 0.014 μm) show a significantly reduced bacterial colony count (from 130 ± 6 to 42 ± 3) with an antibacterial rate of 67.7%, as the water contact angle on TC4 surfaces increases with decreasing roughness (reaching 80.95° on the smoothest surface), making bacterial adhesion more challenging and reducing colonization. The composite resin coating based on a mixture of titanium-doped hydroxyapatite and titanium dioxide (Ti-HA/TiO₂) further improves the antibacterial rate to 74.6% through a photocatalytic synergistic effect and endows TC4 with excellent remineralization capacity—mineralization deposits appear on the coated surface after 3 days of immersion in artificial saliva, while no obvious deposits are found on uncoated rough and smooth surfaces even after 7 days—thereby enhancing its bioactivity effectively. This study on the modification of Ti-based implant surfaces will enrich the field by introducing new technologies and methodologies. These advancements provide a theoretical basis for improvement of the remineralization capacity and antibacterial properties of Ti-based dental implants, thereby promoting broader biomedical applications. Full article

(1) Background: University food service establishments are complex environments, where high turnover and handling practices create conditions for microbial persistence. Food-contact surfaces (FCSs) and handlers’ hands (FHs) function as dynamic reservoirs, facilitating the circulation of contaminants within these institutional settings. This study aimed to characterise the microbiological contamination of FCSs and FHs in university food service establishments in Northern Portugal and to evaluate their role as interconnected environmental reservoirs within the indoor built environment. (2) Methods: A total of 590 samples were analysed from two universities in Northern Portugal (L1, L2), comprising 380 FCS and 210 FH samples. Aerobic colony counts (ACCs), Enterobacteriaceae, and Moulds and yeasts (MYs) were analysed according to ISO methods. FH samples were additionally screened for Escherichia coli and Staphylococcus spp. (3) Results: Overall, 35.5% of FCSs were classified as non-compliant, according to microbial criteria based on guideline values from the National Health Institute Dr. Ricardo-Jorge (INSA), with non-compliance primarily driven by elevated ACCs and MYs. Based on a Generalised Linear Model (GLM), establishment types (canteens vs. cafes) were associated with Enterobacteriaceae levels (p = 0.016), whereas ACCs and MYs were not significantly associated with district, establishment type, or functional surface category (p > 0.05). Differences between left and right hands showed small effect sizes, and location was a highly significant determinant of hand hygiene acceptability. (4) Conclusions: FCSs and FHs act as relevant contamination reservoirs in these settings. The results indicate that Enterobacteriaceae levels on FCSs differed between establishment types, while ACCs and MYs showed no significant variation across the evaluated environmental factors. Marked differences in hand hygiene acceptability between campuses support the implementation of targeted interventions, including the optimisation of cleaning and disinfection protocols, the structured training of food handlers, and the routine microbiological monitoring of surfaces and hands to improve institutional food safety. Full article

Background: The emergence of alternative methods of obtaining groceries since the COVID-19 pandemic has raised new concerns regarding food safety. In this study, we sought to evaluate these concerns by evaluating how the procurement method of ground beef impacts the microbial load in the beef, as this has not been thoroughly studied. Methods: Specifically, we compared beef samples obtained from in-store shopping, grocery delivery, and meal kit delivery services to determine if these new, more convenient methods of grocery shopping impact the total microbial load or Escherichia coli present in the beef. We homogenized a total of 65 beef samples and plated dilutions on trypticase soy agar, MacConkey agar, and CHROMagar. Results: We found that in-store samples had the highest microbial load with an average of 5.06 log CFU/g, while grocery delivery samples resulted in an average of 4.76 log CFU/g and meal kit samples had an average of 4.23 log CFU/g when plated on TSA. This represents a 6.7-fold change between in-store samples and meal kit samples. These differences were not statistically significant (p = 0.1, ANOVA). When plated on MacConkey agar, in-store samples had a bacterial count at 3.0 log CFU/g, while grocery delivery samples had 2.99 log CFU/g and meal kit delivered samples had 3.05 log CFU/g. Suspected E. coli O157 colonies were detected using CHROMagar plates, as these plates function to change the coloration of positive E. coli O157 colonies to pink. Suspected E. coli O157 colonies were observed in three in-store samples, two grocery delivery samples, and one meal kit sample. After confirmatory agglutination testing, one meal kit sample was confirmed as E. coli O157. Conclusions: While trends suggest possible lower microbial contamination in delivery methods versus in-store shopping procurement, no statistical significance between methods was found. These findings indicate no significant changes in microbial loads in delivered ground beef, and the high variance suggests that all procurement methods still pose some level of risk. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) often exhibits limited clinical response to targeted therapies, such as Cetuximab. Identifying key drivers of tumor progression and elucidating the factors that modulate therapeutic sensitivity are essential for improving clinical outcomes. In this study, we aimed to investigate the role of CAV2 in HNSCC proliferation and its impact on Cetuximab sensitivity. Methods: Prognosis-associated genes in HNSCC were screened using the The Cancer Genome Atlas (TCGA) database. The functional role of Caveolin-2 (CAV2) in cell proliferation and apoptosis was assessed via Cell Counting Kit-8 (CCK-8), colony formation, and flow cytometry assays. Mechanistic insights were obtained through co-immunoprecipitation, ubiquitination assays, and proteomic analysis. The impact of CAV2 on Cetuximab sensitivity was evaluated both in vitro and in a xenograft mouse model. Results: Clinical analysis of 43 pairs of HNSCC tumor and adjacent normal tissues revealed that elevated CAV2 expression was significantly associated with poor prognosis in HNSCC patients (95%CI: 1.197–1.7518, p = 1.33 × 10⁻¹³). In vitro, knockdown of CAV2 suppressed cell proliferation and significantly increased apoptosis rates (from 5.1% to 10.8%, p = 0.004). Mechanistically, CAV2 interacted with the PACT protein and disrupted the PACT-PKR axis via the ubiquitin–proteasome pathway. Notably, CAV2 deficiency synergized with Cetuximab treatment, reducing the the half maximal inhibitory concentration (IC₅₀) value by 6-fold compared with control cells and suppressing tumor growth by 48.41% in xenograft models compared to Cetuximab monotherapy (p < 0.0001). Conclusions: In conclusion, these findings establish CAV2 as a critical regulator of HNSCC progression and Cetuximab sensitivity via post-translational modulation of the PACT–PKR axis. Targeting the CAV2/PACT/PKR axis may therefore represent a promising therapeutic strategy to potentiate the efficacy of EGFR-targeted therapy in patients with HNSCC. Full article

Background: Dental caries, primarily caused by Streptococcus mutans (S. mutans), is a prevalent condition with significant global impact. Trans-cinnamaldehyde (TC), a phytochemical derived from the cinnamon plant, has shown promising antibacterial and antibiofilm activity against S. mutans. This study aimed to evaluate the anti-cariogenic effects of TC on S. mutans using an innovative mouse jaw explant model. Methods: TC was diluted in an organic solvent across various concentrations. Initially, cytotoxicity assays were performed at all tested TC concentrations. Sub-minimum bactericidal concentrations were then used to examine the distribution and morphology of S. mutans biofilms. Hemi-mandibles were dissected from euthanized, healthy, seven-week-old female mice to study the impact of TC on the cariogenic activity of S. mutans using stereoscopic analysis. Finally, pH changes during exposure to cariogenic conditions and post-treatment bacterial viability were measured. Results: In vitro data demonstrate that TC doses of ≤625 µg/mL were non-cytotoxic. Treatment groups exposed to TC exhibited altered bacterial morphology, including abnormal and incomplete cell division. In the mouse jaw explant model, TC doses of ≥625 µg/mL showed anti-cariogenic effects, evidenced by the absence of visible carious lesions. Additionally, pH changes and post-treatment viable bacterial counts corresponded with the observed anti-cariogenic activity. TC doses ≤625 µg/mL led to a pH drop over time and the presence of bacterial colonies. Conclusions: TC exhibits significant anti-cariogenic activity against S. mutans in the mouse model. Our findings suggest that 625 µg/mL is the lowest non-toxic concentration of TC that effectively inhibits cariogenic activity. Full article