Search Results (3,195)

Achieving in situ and time-resolved monitoring of microbial metabolites without disrupting the microbial growth environment remains a key challenge in electrochemical biosensing. Herein, we propose a self-healing bilayer hydrogel-based solid-state electrochemical sensing platform for the in situ, time-resolved analysis of purine metabolites produced by Escherichia coli (E. coli). This platform integrates an upper Agar culture module and a lower borax-crosslinked poly(vinyl alcohol) (PVA) detection module, forming a contiguous structure that allows metabolites (e.g., guanine, xanthine, hypoxanthine) to migrate across the solid–solid interface for sensitive electrochemical detection. The detection layer exhibits excellent ionic conductivity; when coupled with its robust structural self-healing capacity, the platform achieved a detection limit of 0.05 µM for guanine. For E. coli detection, a linear response range of 1.1 × 10⁶ to 9.5 × 10⁶ CFU·mL⁻¹ (R² = 0.9974) was obtained, and relative standard deviations (RSDs) of less than 2.34% even after two weeks of storage. Leveraging this integrated design, the platform enables continuous, label-free tracking of bacterial metabolic dynamics throughout all growth phases. Notably, it detects metabolic transition points earlier than traditional plate counting methods and accurately evaluates antibiotic inhibition trends, with results consistent with colony-forming unit (CFU) analysis. This integrated culture–detection architecture thus provides a versatile strategy for functional microbial analysis and rapid antimicrobial susceptibility testing. Full article

Background: Natto, a well-known fermented soybean product beneficial for bone health, remains unclear in its mechanism. Methods: This study investigated its effect on secondary osteoporosis (OP) in mice. Results: Natto significantly inhibited weight loss, bone quality deterioration, and bone morphological damage, and regulated OPG/RANKL pathway protein expression (p < 0.05) in OP mice. Analysis of 16S rRNA revealed that natto increased gut microbiota α-diversity and the abundance of Sutterella, Roseburia, and Coprococcus, while reducing harmful bacteria such as Streptococcus, Shigella, and Helicobacter. These microbial changes positively correlated with body weight, bone size, and serum osteogenic metabolism in OP mice. Serum metabolomics showed differential metabolites of the natto group enriched in PPAR signaling and primary bile acid biosynthesis. Verification by mRNA and ELISA indicated that the upregulated liver and circulating PPARα by natto may regulate downstream bile acid pathways, linking gut microbiota to multi-organ metabolic functions. Conclusions: In summary, natto may act on gut microbiota to alleviate bone loss via the “gut microbiota–bile acid–OPG/RANKL” network, targeting multiple organs including gut, liver, and bone. This provides a theoretical basis for natto dietary intervention in osteoporosis prevention through the gut–bone axis. Full article

The efficacy of plant-derived antimicrobials in meat systems is frequently limited by interactions with proteins, lipids, and other food matrix components that reduce the bioavailability and antimicrobial activity of phytochemicals. This study evaluated the antimicrobial effectiveness of Verbascum sinaiticum (V. sinaiticum) leaf extract encapsulated using maltodextrin (MD), gum arabic (GA), and a maltodextrin–gum arabic blend (MDGA, 8:2 w/w) through freeze-drying for application in raw beef during refrigerated storage (4 °C). The encapsulation systems exhibited process yields of 42.5–54.7%, encapsulation efficiencies of 78.3–92.5%, and loading capacities of 18.5–24.3 mg GAE/g DW, with MDGA showing the highest encapsulation efficiency. The effects of encapsulation on microbial inhibition, physicochemical properties, and sensory quality were investigated over 15 days of storage. Aerobic plate counts in the control increased from 3.04 to 8.26 log CFU/g, whereas encapsulated treatments showed significantly lower final counts (p < 0.05), reaching 7.89 log CFU/g (MD), 7.96 log CFU/g (MDGA), and 7.95 log CFU/g (GA). Similarly, encapsulated treatments reduced Escherichia coli counts during storage, with maltodextrin (MD) exhibiting the greatest inhibitory effect (6.23 × 10⁵ CFU/g) compared with the control (6.93 × 10⁵ CFU/g) on day 15. However, reductions in Staphylococcus aureus, E. coli, Candida albicans, and Bacillus cereus remained below 1 log CFU/g, indicating limited antimicrobial efficacy under the tested conditions. All encapsulated treatments slowed pH increases during storage (6.20–6.34) relative to the control (6.62) on day 15 and preserved aroma quality throughout the storage period. Overall, encapsulation improved the antimicrobial performance of V. sinaiticum extract compared with the free extract, particularly in MD-based systems; however, the antimicrobial effects in beef remained modest. These findings highlight both the potential and current limitations of encapsulated plant-derived antimicrobials for meat preservation and emphasize the need for optimized delivery systems to enhance efficacy in complex food matrices. Full article

This study evaluated the microbiological quality, phenolic compound profile, antimicrobial activity against foodborne pathogens, and the presence of potential chemical markers associated with microplastic polymers in 35 commercial bee pollen samples obtained from the seven geographical regions of Türkiye. Microbiological analyses included the enumeration of total mesophilic aerobic bacteria, coliforms, yeasts and molds, lactobacilli, lactococci, and psychrophilic bacteria. Antimicrobial activity was determined against Escherichia coli O157:H7, Staphylococcus aureus, and Salmonella Enteritidis using the disk diffusion method. Phenolic compounds were analyzed by HPLC-DAD, while characteristic pyrolysis products associated with microplastics were analyzed by PY-GC/MS. The results indicated that the pollen samples generally exhibited low microbial contamination levels and variable antimicrobial activity, depending on their geographical origin. Quercetin was identified as the predominant phenolic compound, and samples with higher phenolic content tended to show stronger antimicrobial effects, particularly against S. aureus. PY-GC/MS analyses revealed the presence of several chemical markers potentially associated with plastic polymers in a considerable proportion of the samples. Spearman correlation analysis showed a positive correlation between total phenolic content and particularly S. aureus inhibition. These findings highlight the nutritional and functional value of bee pollen while also drawing attention to emerging food safety concerns related to possible exposure to plastic-associated environmental contaminants. Regular monitoring of bee pollen is therefore recommended to ensure product quality and consumer safety. Full article

Bacterial–fungal interactions are prevalent in microbial communities, and fungi often facilitate bacterial dispersal along networks created by fungal hyphae. Using a microfluidic device, we examined how diverse bacterial species disperse in monoculture versus travel in coculture with Aspergillus flavus. Most of the bacteria traveled further when in coculture, although this was not absolute. Two bacteria showing significant dispersal rates only in coculture were the human pathogens Listeria monocytogenes and Staphylococcus aureus. Mechanistically, L. monocytogenes dispersal required flagella, with dispersal impaired in flagellar mutants but enhanced in ∆mogR strains that upregulate flagellar expression. In contrast, the non-flagellar bacterium S. aureus exhibited a unique, wave-like dispersal pattern along the hyphae, a phenomenon that was abolished in agr quorum-sensing mutants deficient in phenol-soluble modulins (PSMs). In a triculture of L. monocytogenes, S. aureus, and A. flavus, L. monocytogenes limited S. aureus dispersal along the fungal hyphae; however, this inhibition was dependent on an intact L. monocytogenes quorum system. Our findings reveal that bacterial motility on fungal networks arises from diverse, species-specific mechanisms, including flagella, transcriptional regulation, potential quorum-sensing-mediated interactions, as well as other notable dispersal phenomena that warrant further investigation. Full article

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

In Mexico, cheese whey (CW) is commonly treated as a dairy wastewater despite its high lactose and nutrient content. This study evaluated cheese whey (CW) and ultrafiltered cheese whey (UF-CW) as low-cost substrates for the cultivation of the probiotic strains Lactobacillus acidophilus and Lactococcus lactis. The proposed bioprocess simultaneously enables the production of probiotic biomass and lactic acid, a high-value platform chemical with broad applications in the food, pharmaceutical, and biopolymer industries. In the first experimental trials, in which CW and UF-CW were used solely as media, fermentations lasted 36 h at 30 and 37 °C, with initial pH levels of 5 and 7. CW demonstrated a greater capacity to support the growth of lactic acid bacteria. Thus, to increase the fermentative capability of UF-CW, it was supplemented with yeast extract (YE) or corn steep liquor (CSL), and CaCO₃ was added to stabilize pH, as low pH values inhibit growth and lactic acid production. The proposed strategy notably improved microbial growth in UF-CW, increasing Lc. lactis and L. acidophilus populations from 8.3 and 8.2 Log₁₀ CFU/mL to 9.3 Log₁₀ CFU/mL, respectively. The findings suggest that dairy wastewater can be effectively repurposed as a low-cost cultivation medium for these bacteria. ASPEN simulation analyses demonstrated that lactose conversion efficiency and final product concentration were key factors affecting process performance and economic feasibility. Among the evaluated scenarios, a 45% lactose-to-lactic acid conversion yielded the most economically favorable process performance compared with conversions of 10% and 25%. Future research should focus on enhancing fermentation yields and adopting more efficient downstream recovery techniques. Full article

This study evaluated how a lemon essential oil–rutin–chitosan coating (CS-LEO/NE-R), prepared from a 5:95 (v/v) lemon essential oil/rutin-containing nanoemulsion and a chitosan solution containing 1.5% chitosan, 1% acetic acid, and 5% glycerol, combined with controlled freezing-point storage preserves seasoned white snakehead fillets. Compared with controlled freezing-point storage alone, the combined treatment significantly inhibited oxidation, volatile nitrogen accumulation, texture softening, and microbial growth. On Day 10, the coating group recorded a total viable count of 4.98 log CFU/g, which was below the national limit (5 log CFU/g), whereas the control group went beyond this limit by Day 7. This extended the microbiological and physicochemical acceptability period by approximately 3 days under the present experimental conditions. Untargeted metabolomics revealed 2267 metabolites, and the differentially abundant ones mainly comprised amino acids, heterocyclic compounds, aldehydes, ketones, and esters. KEGG enrichment suggested that changes in linoleic acid metabolism, terpenoid related annotations, the actin cytoskeleton, and the phospholipase D signaling pathway were associated with delayed quality deterioration. This work provides a theoretical basis for the composite biopreservation of aquatic products. Full article

Large volumes of waste by-products are generated by the continuing growth of the fish production industry. To address this issue, this study valorized the protein hydrolysate extracted from fish waste for use as an active compound in a packaging system. An edible film was developed based on a chitosan/gelatin (CG) matrix, incorporated with fish protein hydrolysate (FPH) extracted from snakeskin gourami processing waste, at concentrations of 0%, 2%, 4%, 6%, and 8%. Introducing FPH into the film’s matrix enhanced the UV protection properties but decreased transparency. The incorporation of 4% FPH significantly increased the film tensile strength and antioxidant capacity by 47.67% and 65.04%, respectively, compared to the control, while concentrations of FPH exceeding 4% had a detrimental effect on film mechanical and antioxidant capacities. 4P-CG was identified as the optimal formulation and applied as an edible coating for sun-dried snakeskin gourami at 4 °C for 14 days. The 4P-CG coating preserved the quality of sun-dried fish by reducing weight loss and inhibiting microbial growth, which extended the shelf life by four days compared to the control (non-coated) and other CG-coated fish. These findings suggest that 4P-CG is a promising, sustainable active packaging solution for enhancing the stability and safety of fatty aquatic related products while contributing to the circular economy through waste reduction. Full article

Chromium is an environmental pollutant with high toxicity and carcinogenicity. It can induce severe oxidative stress and DNA damage after entering the human body through the food chain. As a plant growth-promoting rhizobacterium (PGPR) with both heavy metal tolerance and plant growth-promoting properties, Klebsiella variicola has considerable potential for the remediation of chromium contamination. In this study, chicory served as the experimental plant to explore the mitigating impacts of K. variicola on stress induced by hexavalent chromium (Cr(VI)) at a concentration of 400 mg/kg. The results showed that chromium severely inhibited the growth of chicory. In contrast, K. variicola significantly reduced the soil chromium content. As the chromium content decreased, the activities of soil urease, sucrase, catalase, and alkaline phosphatase were restored, increasing by 32.60–53.69%. Accordingly, the contents of total phosphorus, available phosphorus, total nitrogen, available nitrogen, soil organic carbon, and available potassium also increased by 34.71–51.81%. In addition, K. variicola reversed the decline in microbial diversity induced by chromium stress, promoted the growth of beneficial bacteria such as Acidobacteriota and Chloroflexota, and enhanced the stability of soil ecosystem functions. Ultimately, the growth inhibition of chicory caused by chromium stress was alleviated, with fresh weight, root length, maximum leaf width, maximum leaf length, plant height, and stem diameter significantly increasing by 21.89–61.60%. This study enhances our comprehension of the various functions of PGPR when exposed to heavy metal stress, and provides support for the development of microbe–plant combined strategies in the remediation of chromium-contaminated soils. Full article

The accumulation of intermediate products, particularly volatile fatty acids (VFAs) like propionic acid (HPr) or its dissociated form, can inhibit biogas production during anaerobic digestion (AD) at low concentrations. Knowledge about the response of microorganisms to VFA inhibition can help control the digesters. In this study, we aimed to determine how sodium propionate (NaPr) inhibits the AD of municipal sewage sludge by identifying shifts in the microbial community. Four 5 L reactors were operated in semi-continuous mode using sewage sludge and then loaded with different levels of NaPr. The reactors operated at 37 °C with two hydraulic retention times. The results show that there was no apparent inhibition of biogas production at NaPr loading up to 20.3 mmol·L⁻¹. However, moderate inhibition was observed at 81 mmol·L⁻¹, corresponding to an approximate 10% decrease in methane production, while a ≈40% decrease in methane production was observed at 135.3 mmol·L⁻¹. Sequencing analysis revealed that the community composition was dominated by Bacillota, Bacteroidota, Proteobacteria, Chloroflexi, and Cloacimonadota, with Halobacterota and Euryarchaeota as the main archaeal groups. PERMANOVA revealed incubation time as the primary driver of community structure, followed by NaPr concentration. Elevated NaPr levels resulted in a decline in Methanothrix and Methanobrevibacter and promoted distinct syntrophic propionate-oxidizing bacteria (SPOB). Full article

Background: Polygonum cuspidatum (Hu Zhang) is a polyphenol-rich botanical in which resveratrol occurs at low levels mainly as polydatin. In this study, we generated a microbially converted P. cuspidatum extract (CPE) with markedly enriched resveratrol content from the unconverted P. cuspidatum extract (PE), and evaluated its anticancer efficacy and safety in comparison with those of the unconverted extract. Methods: High-performance liquid chromatography (HPLC), A549 cell-based assays, an A549 xenograft model, and a 28-day repeated-dose rat study were performed. Results: HPLC showed near-complete depletion of polydatin, marked enrichment of resveratrol, and a modest reduction in emodin. CPE more effectively inhibited A549 cell proliferation and migration than PE, suppressed NLRP3 inflammasome and nuclear factor kappa B (NFκB) signaling, and promoted reactive oxygen species (ROS) accumulation and mitochondrial apoptosis. Oral CPE also significantly reduced tumor growth in an A549 xenograft model. In a 28-day repeated-dose rat study, no treatment-related abnormalities were observed in blood biochemistry or histopathology. Conclusions: These findings support CPE as a promising functional food ingredient. Full article

Honey has been appreciated for its medicinal properties since ancient times; it is known as a powerful antimicrobial agent, and as a result of the increase in antibiotic resistance of various bacterial strains, honey began to be used in complementary therapies to combat microbial infections. The study aimed to identify the antimicrobial potential of two honey varieties (Acacia honey and polyflora honey) with different botanical and geographical origins on standardized bacterial strains or isolated from patients, some of which showed antibiotic resistance. The physicochemical parameters of the honey varieties analyzed were: water content, impurities, pH of honey, acidity, mineral content, reducing sugar content, total phenol content, and antioxidant capacity (DPPH). The antibacterial potential of the honey varieties was assessed based on tests to determine cell viability and the capacity to inhibit biofilm formation. The Gram-positive strains studied were Staphylococcus aureus (ATCC25923), Staphylococcus aureus MRSA (ATCC43300), Streptococcus pneumoniae (ATCC49619), and the Gram-negative strain was Escherichia coli (ATCC25922). In addition, bacterial strains isolated from the patients were Staphylococcus aureus, Staphylococcus aureus MRSA, Streptococcus pneumoniae, and Escherichia coli. The results of the microbiological tests were correlated with the physicochemical parameters, suggesting that the content of polyphenolic compounds with antioxidant activity and acidic pH may contribute to the antimicrobial potential of honey. Also, statistical analyses indicated significant differences regarding the antimicrobial potential of honey on Gram-positive versus Gram-negative bacteria, standardized versus isolated bacteria from patients, but also for antibiotic-resistant bacteria compared to the other strains studied. Full article

Background/Objectives: Titanium alloy Ti₆Al₄V remains the gold standard in dental implantology due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, implant-associated infections and insufficient osseointegration continue to represent major clinical challenges, mainly related to bacterial biofilm formation and suboptimal surface–tissue interactions. Biofilm formation refers to the adhesion, accumulation, and growth of microbial communities embedded within a self-produced extracellular polymeric matrix on implant surfaces, which contributes to bacterial persistence and resistance to host defense mechanisms. This review aims to critically evaluate recent advances in multifunctional bioceramic coatings for dental implants, with a particular focus on zirconia (ZrO₂)-based systems and their antibacterial mechanisms. Methods: A structured literature analysis was conducted using major scientific databases including PubMed, Scopus, and Web of Science, focusing mainly on studies published between 2015 and 2025 related to CaP, Ag, and ZrO₂-based coatings for dental implants. The review examines their physicochemical properties, antibacterial strategies, ion release behavior, and biological responses, including osteogenic activity and biofilm inhibition. Particular attention is given to hybrid systems integrating multiple functional phases. Results: CaP coatings exhibit excellent osteoconductivity and promote early osseointegration but show limited intrinsic antibacterial activity. Ag-based coatings provide strong broad-spectrum antimicrobial effects through controlled Ag⁺ ion release, although concerns regarding cytotoxicity and dose-dependent responses remain. ZrO₂ coatings significantly enhance corrosion resistance and surface stability, while their antibacterial performance can be improved through nanostructuring, laser surface modification, and ionic doping. Hybrid Ag–CaP–ZrO₂ coatings demonstrate improved antibacterial activity, enhanced corrosion resistance, and better regulation of ion release kinetics and osteogenic response compared with single-component coating systems. Conclusions: Multifunctional bioceramic coatings represent a promising strategy for improving the performance of dental implants and addressing the dual challenge of infection control and tissue integration. However, challenges remain regarding long-term stability, controlled ion release, and limited clinical validation. Future research should focus on the development of smart, stimuli-responsive coatings and standardized evaluation protocols to facilitate clinical translation. Full article

Fusarium oxysporum f. sp. lycopersici is one of the most destructive soilborne pathogens affecting tomato production, reducing plant growth and yield and highlighting the need for sustainable management alternatives. Streptomyces spp. are promising microbial candidates due to their ability to combine antifungal activity with plant growth promotion characteristics. The objective of this study was to evaluate the biofertilizer and antifungal potential of Streptomyces spp. in Chonto tomato (Solanum lycopersicum Mill.) under greenhouse conditions. Seventy actinobacterial strains were screened in vitro against F. oxysporum, and eight exhibited significant antagonistic activity. Based on antagonistic activity, enzymatic profile, cytotoxicity, and plant growth-promoting potential, strains 1B260 and 445 were selected for greenhouse assays. Strain 1B260 achieved 43.5% mycelial growth inhibition and showed the highest phosphate-solubilizing capacity (420 µg/mL), while both strains displayed proteolytic and cellulolytic activity, low cytotoxicity in human skin cell lines (HaCaT and HDFa), nitrogen fixation, and ammonia production. In greenhouse assays under non-infected conditions, 1B260 showed the most consistent biofertilizer effect, promoting stem elongation. Under pathogen pressure, strain 445 improved plant performance compared to the infected control. Overall, strains 1B260 and 445 exhibited complementary roles in tomato crop management, highlighting the potential of multifunctional Streptomyces inoculants for sustainable biofertilization and biocontrol strategies. Full article