Search Results (52)

Background: Rising antifungal and antibiotic resistance among Candida species, Staphylococcus aureus, and Enterococcus faecalis has renewed interest in antimicrobial photodynamic therapy (aPDT) as a resistance-independent strategy. Riboflavin 5′-phosphate is a biocompatible, blue-light-activated photosensitizer, but standardized dosing across fungal and bacterial targets is lacking. Objective: The aim of this study was to systematically optimize pre-irradiation incubation time, photosensitizer volume, irradiation time, and laser power for riboflavin 5′-phosphate aPDT (450 nm diode laser) against C. albicans, C. glabrata, C. krusei, S. aureus, and E. faecalis, and compare species susceptibility under optimized conditions. Methods: ATCC strains were treated with 0.1% riboflavin 5′-phosphate across four groups (photodynamic, photosensitizer-only, laser-only, control) in a staged design optimizing incubation (1–30 min), photosensitizer volume (50–150 µL), irradiation time (10–120 s), and power (50–400 mW). Viable counts (CFU/mL) were quantified. Results: Significant reductions occurred only with combined light-plus-photosensitizer treatment. Optimal parameters were 15 min incubation, 100 µL photosensitizer for Candida spp. (50 µL for bacteria), and 120 s at 400 mW, though C. albicans and C. krusei plateaued by 60 s. Maximum reductions were modest: 53.5% (C. albicans), 46.7% (S. aureus), 37.9% (C. glabrata), 35.9% (C. krusei), and 26.5% (E. faecalis), all below 1 log₁₀. A significant light × photosensitizer interaction, confirming photodynamic specificity, was seen for C. albicans, C. glabrata, and S. aureus, but not C. krusei or E. faecalis. Conclusions: Riboflavin 5′-phosphate aPDT under 450 nm light produces reproducible, dose-dependent, species-specific antimicrobial activity, best suited as an adjunctive rather than stand-alone therapy pending biofilm and in vivo validation. Full article

Singlet oxygen is produced by light-dependent excitation of molecular oxygen using photosensitizers. Using blue light and riboflavin (RF) or riboflavin phosphate (RFP) as photosensitizers, we studied the reaction of singlet oxygen with tertiary amines in aqueous solution because many are used as biochemical buffers and as electron donors in photoreduction reactions. The reactions of singlet oxygen with multiple tertiary amines, including ethylenediamine tetraacetic acid (EDTA), bicine, and triethanolamine (TEOA), produced micromolar hydrogen peroxide (H₂O₂) as the stable end product. For bicine and TEOA, but not EDTA, H₂O₂ yield increased as pH increased due to their higher amine pKa values. A white LED used in conjunction with riboflavin and tertiary amines also produced H₂O₂, a contaminant likely to form during tissue culture manipulations. Direct photoreduction of 2,6-dichlorophenolindophenol and 2,3-dimethoxy-5-methyl-p-benzoquinone was achieved using blue light, RF or RFP, and tertiary amines as electron donors. With RF, EDTA was the optimal electron donor for both substrates, whereas with RFP, bicine and TEOA were superior to EDTA. Photochemical redox cycling of both quinones produced H₂O₂ via singlet oxygen-dependent re-oxidation of reduced quinols. Several amine buffers, including HEPES and PIPES, reacted with singlet oxygen to produce H₂O₂ but did not function as electron donors in quinone photoreduction assays. Full article

The utilization of sugarcane molasses as a low-cost carbon source for riboflavin production is hindered by the reactive oxygen species (ROS) stress induced by its complex components, which suppresses microbial metabolism. To address this, we employed adaptive laboratory evolution (ALE) under progressively increasing stress to develop a sugarcane molasses-tolerant and high-yielding Ashbya gossypii. The adapted strain achieved a riboflavin titer of 298.39 ± 2.01 mg/L, representing a 99.4% increase over the parental strain (149.66 ± 4.97 mg/L), accompanied by a 96% increase in biomass (dry cell weight). Notably, the specific riboflavin production per unit biomass showed no significant difference between the two strains, indicating that the improved total yield was primarily driven by enhanced biomass accumulation. Transcriptomic analysis revealed the molecular basis for this enhanced biomass accumulation—the elevated expression of antioxidant enzymes (SOD1, PRDX5) mitigated ROS levels to support cellular growth, while the coordinated upregulation of the pentose phosphate pathway (E2.2.1.1) and purine metabolism genes (PPAT, ADE5, PFAS, ADSL) enhanced the supply of biosynthetic precursors, ribulose-5-phosphate (Ru5P) and GTP, for nucleotide biosynthesis and cell proliferation. These metabolic adjustments collectively enabled the adapted strain to achieve robust growth under sugarcane molasses stress, thereby driving the overall increase in riboflavin production. This study elucidates the molecular mechanism underlying ALE-improved riboflavin production and provides a promising strategy for its industrial fermentation using sugarcane molasses. Full article

Background: Citrus components potentially suppress adipogenic differentiation and lipid accumulation, and exhibit anti-inflammatory and antioxidant effects. We hypothesized that the bioactive compounds in Citrus junos Sieb ex Tanaka (yuzu) fruit peel can alter the systemic metabolism and productivity of beef cattle. Methods: Japanese Brown (JBR) steers were fed with a diet supplemented with 2.5% yuzu peel during the last month of the finishing period. To investigate the effect of dietary yuzu supplementation (DYS) on beef and liver metabolism, we explored the metabolomic profiles of longissimus thoracis (LT, loin) muscle at 14 d postmortem using capillary electrophoresis (CE-TOF/MS) and high-performance liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). Results: The DYS treatment enhanced the beef fat score compared to that recorded in beef in the no-DYS (None) group (p = 0.050); however, the other carcass quality traits were not significantly different between the DYS and None groups. CE-TOF/MS and LC-TOF/MS revealed 242 and 107 annotated peaks, respectively, for the LT muscle. DYS significantly increased 9(S)-hydroxyoctadecadienoic acid (9-HODE, a beef flavor precursor), cyclo(-Leu-Pro), spermidine, asymmetric dimethylarginine, and 7α-hydroxycholesterol levels and reduced 2-ethylhydracrylic acid (2-EHAA), γ-tocopherol, coenzyme Q10 (CoQ10), sphingomyelin(d18:1/16:0), Cys-Gly, Tyr-Arg, and palmitoylcarnitine levels in postmortem LT muscle (p < 0.050). Concomitantly, in the fresh liver, DYS increased acetyl-CoA, 6-phosphogluconic acid, S-methylglutathione, ATP, ribulose 5-phosphate, and ADP levels and suppressed the content of thiamine, Ala-Ala, riboflavin, and ascorbate 2-sulfate (p < 0.050). Conclusion: Collectively, yuzu ingredients activated ATP production in the liver through the elevation of hepatic energy metabolism primarily in the citrate cycle and β-oxidation, and potentially altered muscle metabolism, including linoleic acid oxidation, FAD-mediated electron transport chain, and isoleucine catabolism, as demonstrated in the reduced accumulation of 2-EHAA and CoQ10 in DYS beef. Moreover, DYS likely affects the gut microbiome by enhancing the production of cyclo(-Leu-Pro), an antimicrobial dipeptide. Full article

Riboflavin (RF; vitamin B₂) is an essential micronutrient with broad applications in the food, feed, pharmaceutical, and cosmetic industries and is increasingly relevant in bioelectrochemical systems and environmental biotechnology. Microbial fermentation has replaced chemical synthesis as the dominant industrial production route due to its superior sustainability and scalability. However, despite substantial progress, RF biosynthesis remains constrained by imbalances in precursor supply, complex redox regulation, and regulatory feedback mechanisms that limit metabolic flux toward guanosine triphosphate and ribulose-5-phosphate. This review provides an updated, integrative analysis of RF biotechnology, encompassing biosynthetic pathways, transcriptional and redox-regulation, strain improvement strategies, and fermentation process optimization. Representative industrial producers—including Bacillus subtilis, Ashbya gossypii, and Candida famata—are critically evaluated for productivity, yield, and metabolic robustness, with reported titers reaching up to 29 g L⁻¹ in engineered systems. Emerging microbial platforms, including lactic acid bacteria, thermotolerant and methylotrophic microorganisms, and electroactive bacteria, are discussed in the context of niche applications such as food biofortification and microbial fuel cells. Special emphasis is placed on oxidative stress as a regulatory signal influencing RF overproduction, metabolic rewiring strategies to alleviate precursor bottlenecks, and the biosynthesis of RF derivatives (FMN, FAD, roseoflavin, and 8-aminoriboflavin). In addition, biosafety, regulatory constraints, concerns about genome stability, and antibiotic-free engineering approaches are examined as critical determinants of future industrial competitiveness. By integrating molecular regulation, metabolic engineering, fermentation design, emerging applications, and regulatory perspectives within a unified framework, this review outlines current bottlenecks and future directions for developing safer, more robust, and economically competitive RF-producing microbial platforms. Full article

Background: Exclusive breastfeeding for the first 6 months of corrected age (CA) is recommended for premature infants with very low birth weight (<1500 g) (VLBW). B vitamins are essential for normal development and growth, including DNA methylation, and we investigated whether exclusive breastfeeding for the first 6 months provides an adequate cobalamin, folate, vitamin B6, and vitamin B2 status compared to additional or exclusive formula feeding from term to 12 months CA. Methods: In recruited infants born prematurely with VLBW, levels of vitamin B12 (cobalamin), folate, vitamin B6 (pyridoxal 5′-phosphate, PLP), vitamin B2 (riboflavin), and the metabolic markers, total homocysteine (tHcy) and methylmalonic acid (MMA), were determined at term (n = 35) and at 2 (n = 47), 6 (n = 48), and 12 months (n = 58) CA. Results: Only a minority of the infants were given multivitamin supplementation, and this was associated with higher PLP and riboflavin levels. One-third of the infants were exclusively breastfed to 6 months CA, and these had lower cobalamin, PLP, and riboflavin concentrations compared to formula-fed infants; additionally, 80% had plasma tHcy concentrations ≥ 6.5 µmol/L, indicative of cobalamin deficiency during the first 6 months CA. Serious deficiency of one or more B vitamins was evident in 3–9% of the infants at each time point during the first 12 months CA, more often in breastfed infants, but not exclusively. Conclusions: Exclusive breastfeeding with inadequate multivitamin supplementation and no specific recommendation for introduction of solid food does not provide an adequate B vitamin status in infants born prematurely with VLBW. Nutritional micronutrient recommendations must be improved, and regular evaluation of vitamin status should be implemented in the follow-up for premature VLBW infants. Full article

Bacillus velezensis strain G2T39 is an endophytic bacterium previously isolated from Crotalaria retusa L., with evidenced biocontrol activity against Fusarium oxysporum f. sp. Cubense and Fusarium graminearum. In this study, it was shown that this strain also exhibited biocontrol activity against Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. Vasinfectum, two important crop pathogens in tropical zones. Comprehensive phylogenetic and genomic analyses were performed to further characterize this strain. The genome of B. velezensis G2T39 consists of a single circular chromosome of 4,040,830 base pairs, with an average guanine–cytosine (GC) content of 46.35%. Both whole-genome-based phylogeny and average nucleotide identity (ANI) confirmed its identity as B. velezensis, being closely related to biocontrol and plant growth promotion Gram-positive model strains such as B. velezensis FZB42. Whole-genome annotation revealed 216 carbohydrate-active enzymes and 14 gene clusters responsible for secondary metabolite production, including surfactin, macrolactin, bacillaene, fengycin, bacillibactin, bacilysin, and difficidin. Genes involved in plant defense mechanisms were also identified. Additionally, G2T39 genome harbors multiple plant growth-promoting traits, such as genes associated with nitrogen metabolism (nifU, nifS, nifB, fixB, glnK) and a putative phosphate metabolism system (phyC, pst glpQA, ugpB, ugpC). Additional genes linked to biofilm formation, zinc solubilization, stress tolerance, siderophore production and regulation, nitrate reduction, riboflavin and nicotinamide synthesis, lactate metabolism, and homeostasis of potassium and magnesium were also identified. These findings highlight the genetic basis underlying the biocontrol capacity and plant growth-promoting properties of B. velezensis G2T39 and support its potential application as a sustainable bioinoculant in agriculture. Full article

This study investigates the adaptive mechanisms that enable a single wild barley (Hordeum spontaneum) accession to withstand extreme salinity. Salt stress reshapes plant metabolism and gene expression, offering targets for breeding salt-tolerant cereals. A time-course RNA-Seq experiment was conducted on leaves exposed to 500 mM NaCl, followed by differential expression and functional annotations to characterize transcriptomic responses. Transcriptomic profiling identified 140 dynamically upregulated genes distributed across 19 interconnected metabolic pathways, with phased activation of oxidative phosphorylation, nitrogen assimilation, lipid remodeling, and glutathione metabolism. Central metabolic nodes, including acetyl-CoA, hexadecanoyl-CoA, and ubiquinone, coordinated bioenergetic output, membrane stabilization, and redox homeostasis. Ribose-5-phosphate and ribulose-5-phosphate linked glycolysis and the pentose phosphate pathway, supplying NADPH for antioxidant defense and nucleotide repair, while riboflavin derived from Ru5P enhanced flavoprotein activity. In parallel, glucose and fructose-6-phosphate supported osmotic adjustment and glycolytic flux, and increased sterol and cuticular lipid biosynthesis, including cholesterol-like compounds, reinforced membrane integrity and calcium signaling. Glutathione and N-acetyl-glutamate together mitigated oxidative stress and modulated polyamine metabolism, strengthening cellular resilience under salt stress. These findings outline a coordinated network of metabolic and redox pathways that can guide the engineering of salt-tolerant cereals for sustainable production in saline agroecosystems. Full article

This study investigated the systemic metabolic effects of feeding a Fusarium-contaminated diet to early-lactation Holstein cows, with or without a mycotoxin-deactivating product (MDP; Mycofix^® Plus, BIOMIN Holding GmbH, Tulln, Austria). Thirty cows were divided into three dietary groups: a mildly contaminated control (CTR), a moderately contaminated diet containing zearalenone and deoxynivalenol (MTX), and the same contaminated diet supplemented with MDP. Plasma collected at 56 days in milk was analyzed by untargeted ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS), and multivariate models identified discriminant metabolites and pathways. MTX-fed cows showed alterations in sphingolipid metabolism, including accumulation of ceramide (t18:0/16:0), lactosylceramide, and sphinganine 1-phosphate, consistent with ceramide synthase inhibition and lipid remodeling stress. Increases in estradiol, estrone, and cholesterol sulfate suggested endocrine disruption, while elevated 8-oxo-dGMP indicated oxidative DNA damage. MDP supplementation mitigated these alterations, reducing sphingolipid intermediates, modulating tryptophan and glycerophospholipid pathways, and lowering oxidative stress markers. Metabolites such as riboflavin, pipecolic acid, and N-acetylserotonin could be likely associated with an improved mitochondrial function and redox homeostasis, although future studies are required to confirm this hypothesis. Additionally, MDP-fed cows exhibited distinct shifts in pyrimidine and nucleotide metabolism. Overall, MDP effectively counteracted Fusarium-related metabolic disturbances, supporting its protective role in maintaining lipid balance, hormonal stability, oxidative control, and metabolic resilience. Full article

Background/Objectives: We examined the association between dietary intake and blood concentrations of one-carbon metabolism (OCM)-related nutrients in the European Prospective Investigation into Cancer and Nutrition (EPIC). Methods: Blood concentrations and dietary intake of the vitamins riboflavin (B2), Pyridoxal 5′-phosphate (PLP and B6), folate (B9), B12, and methionine, concentrations of homocysteine, and dietary intake of betaine, choline, and cysteine were pooled from 16,267 participants in nine EPIC nested case–control studies. Correlation analyses between dietary intakes and blood concentrations were carried out. Principal component (PC) analysis identified latent factors in the two sets of measurements. Results: Pearson correlations between dietary intakes and blood concentrations ranged from 0.08 for methionine to 0.12 for vitamin B2, 0.15 for vitamin B12, 0.17 for vitamin B6, and 0.19 for folate. Individual dietary intakes showed higher correlations (ranging from −0.14 to 0.82) compared to individual blood concentrations (from −0.31 to 0.29). Correlations did not vary by smoking status, case–control status, or vitamin supplement use. The first PC of dietary intakes was mostly associated with methionine, vitamin B12, cysteine, and choline, while the first PC of blood concentrations was associated with folate and vitamin B6. Conclusions: Within this large European study, we found weak to moderate associations between dietary intakes and concentrations of OCM-related nutrients. Full article

Hair is continuously exposed to various damaging factors in daily life, necessitating effective protective strategies that balance efficacy with environmental sustainability. In this study, we developed an environmentally friendly hair protective coating using casein proteins crosslinked with tannic acid via riboflavin phosphate-mediated photo-initiation. Casein solutions containing tannic acid (0.05% w/v) and riboflavin phosphate (0.01–0.1% w/v) were prepared and applied to virgin Asian hair, followed by blue light irradiation to initiate crosslinking. The coating formation mechanism was investigated through rheological characterization, which confirmed successful network formation with optimal mechanical stability at a 0.05% tannic acid concentration. Chemical analysis using FTIR spectroscopy revealed subtle but meaningful interactions between the coating components, while SEM analysis demonstrated the coating’s integration with the hair surface. Mechanical property evaluations showed that the photo-crosslinked coating significantly enhanced hair tensile strength by approximately 21% compared to untreated hair, while maintaining appropriate elasticity. Region-specific analysis of stress–strain behavior indicated that the coating extended the initial Hookean region while preserving natural resistance in the post-yield region, creating a balanced enhancement in mechanical properties. This approach offers a promising alternative to conventional hair treatments by utilizing natural, food-grade components and mild processing conditions, addressing growing demands for sustainable hair care solutions that effectively protect against daily damage. Full article

Water-based peel-off nail polishes offer environmental and safety advantages but often suffer from poor mechanical properties. This study investigated the effect of visible-light-induced photocrosslinking with riboflavin phosphate (RFP) on the mechanical properties and adhesion of water-based peel-off nail polish films. Polyurethane films that contained various concentrations of RFP (0–0.1%) were prepared by combining two commercial water-based polyurethane dispersions and characterized through tensile testing, rheological analysis, and adhesion measurements. Under large deformation, the photocrosslinked films showed significantly enhanced mechanical properties, with the highest RFP concentration (0.1%) exhibiting a 54% increase in tensile strength and a 94% increase in Young’s modulus compared with the control, which reflected a transition from physical to covalent network dominance. Rheological analysis under small deformation revealed the formation of complex network structures, where lower RFP concentrations maintained a higher chain mobility beneficial for adhesion, while higher concentrations created more stable networks with enhanced thermal stability, which maintained 50% of the initial storage modulus up to 100 °C. The films exhibited biocompatibility across all RFP concentrations in the cell viability tests, and the straightforward preparation process that used commercially available materials suggests immediate potential for industrial implementation. These results demonstrate that RFP-mediated visible light photocrosslinking offers a promising approach for developing high-performance, environmentally friendly nail polish formulations that combine enhanced durability with user safety and manufacturing practicality. Full article

While photocrosslinked collagen hydrogels show promise in tissue engineering, conventional approaches for property control often require complex chemical modifications or concentration changes that alter their biochemical composition. Here, we present the first systematic investigation of light-intensity-dependent control in riboflavin phosphate (RFP)-mediated photocrosslinking as a novel, single-parameter approach to modulate hydrogel properties while preserving native biochemical environments. We systematically investigated the effects of varying light intensities (100 K, 50 K, and 10 K lux) during hydrogel fabrication through comprehensive structural, mechanical, and biological characterization. Scanning electron microscopy revealed unprecedented control over network architecture, where higher light intensities produced more uniform and compact networks, while swelling ratio analysis showed significant differences between 100 K lux (246 ± 2-fold) and 10 K lux (265 ± 4-fold) conditions. Most significantly, we discovered that intermediate intensity (50 K lux) uniquely optimized mechanical performance in physiological conditions, achieving storage modulus of about 220 Pa after 24 h swelling, compared to about 160 and 109 Pa for 100 K and 10 K lux conditions, respectively. Remarkably, cellular studies using NIH/3T3 fibroblasts demonstrated that lower light intensity (10 K lux) enhanced cell proliferation by 2.8-fold compared to 100 K lux conditions after 7 days of culture, with superior cell network formation in both 2D and 3D environments. This groundbreaking approach establishes light intensity as a powerful single parameter for precise control of both mechanical and biological properties, offering a transformative tool for tailoring collagen-based biomaterials in tissue engineering applications. Full article

Background/Objectives: Petroleum contamination in soil exerts toxic effects on earthworms (Eisenia fetida) through non-polar narcotic mechanisms. However, the specific toxicities of individual petroleum components remain insufficiently understood. Methods: This study investigates the effects of four petroleum components—saturated hydrocarbons, aromatic hydrocarbons, resins, and asphaltenes—on earthworms in artificially contaminated soil, utilizing a combination of biochemical biomarker analysis and metabolomics to uncover the underlying molecular mechanisms. Results: The results revealed that aromatic hydrocarbons are the most toxic fraction, with EC50 concentrations significantly lower than those of other petroleum fractions. All tested fractions triggered notable metabolic disturbances and immune responses in earthworms after 7 days of exposure, as evidenced by significant changes in metabolite abundance within critical pathways such as arginine synthesis, a-linolenic acid metabolism, and the pentose phosphate pathway. According to the KEGG pathway analysis, saturated hydrocarbon fractions induced marked changes in glycerophospholipid metabolism, and arginine and proline metabolism pathways, contributing to the stabilization of the protein structure and membrane integrity. Aromatic hydrocarbon fractions disrupted the arachidonic acid metabolic pathway, leading to increased myotube production and enhanced immune defense mechanisms. The TCA cycle and riboflavin metabolic pathway were significantly altered during exposure to the colloidal fraction, affecting energy production and cellular respiration. The asphaltene fraction significantly impacted glycolysis, accelerating energy cycling to meet stress-induced increases in energy demands. Conclusions: Aromatic hydrocarbons accounted for the highest level of toxicity among the four components in petroleum-contaminated soils. However, the contributions of other fractions to overall toxicity should not be ignored, as each fraction uniquely affects key metabolic pathways and biological functions. These findings emphasize the importance of monitoring metabolic perturbations caused by petroleum components in non-target organisms such as earthworms. They also reveal the specificity of the toxic metabolic effects of different petroleum components on earthworms. Full article

Asthma has been extensively studied in humans and animals, but the molecular mechanisms underlying asthma in Meishan pigs, a breed with distinct genetic and physiological characteristics, remain elusive. Understanding these mechanisms could provide insights into veterinary medicine and human asthma research. We investigated asthma pathogenesis in Meishan pigs through transcriptomic and metabolomic analyses of blood samples taken during autumn and winter. Asthma in Meishan pigs is related to inflammation, mitochondrial oxidative phosphorylation, and tricarboxylic acid (TCA) cycle disorders. Related genes include CXCL10, CCL8, CCL22, CCL21, OLR1, and ACKR1, while metabolites include succinic acid, riboflavin-5-phosphate, and fumaric acid. Transcriptomic sequencing was performed on panting and normal Meishan pigs, and differentially expressed genes underwent functional enrichment screening. Metabolomic analysis revealed differential metabolites and pathways between groups. Combined analyses indicated that lung inflammation is influenced by genetic, allergenic, and environmental factors disrupting oxidative phosphorylation in lung mitochondria, affecting the TCA cycle. Mitochondrial reactive oxygen species, glutathione S-transferases, arginase 1 and RORC in immune regulation, the Notch pathway, YPEL4 in cell proliferation, and MARCKS in airway mucus secretion play roles in asthma pathogenesis. This study highlights that many cytokines and signaling pathways contribute to asthma. Further studies are needed to elucidate their complex interactions. Full article