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A composite is a material in which more than one metal salt or polymer can be mixed to enhance the processed product's physical and chemical properties. Due to their high band gap and enhanced excitation energy, composites can be used in numerous areas, such as solar cells, fuel cells, catalysts, and energy storage. Over a large area of applications in different fields, few studies have examined the ability of composites to sense the efficiency of riboflavin/vitamin B2. The present work explores the utilisation of trimetallic-based nanocomposite nanoparticles (TMNCsNPs) as a sensing material, which is synthesised and characterised in detail. The TMNCsNPs were used to understand the exposure of riboflavin to glassy carbon electrodes (GCE). Several electrochemical parameters were selected for the electrochemical study of the processed sensor. Initially, a long-range concentration of riboflavin (0.976–125 μM in PBS) was selected to check the efficiency of the produced sensor (TMNCsNPs/GCE). Low-to high-potential windows (0.5–15 mV/s) were chosen to measure the effect on TMNCsNPs/GCE in PBS. The chronoamperometry (CA) responses were analysed at different time intervals (0–900 s). The cyclic response (CR) was analysed for TMNCsNPs/GCE sensor for up to one month. The interference of metal was examined, and real sample analysis was also conducted and discussed with possible mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

Riboflavin is a precursor of the essential coenzymes flavin mononucleotide and flavin adenine dinucleotide. Both possess antioxidant properties and are involved in oxidation-reduction reactions, which have a significant impact on energy metabolism. Also, the coenzymes participate in metabolism of pyridoxine, niacin, folate, and iron. Humans must obtain riboflavin through their daily diet because of the lack of programmed enzymatic machineries for de novo riboflavin synthesis. Because of its physiological nature and fast elimination from the human body when in excess, riboflavin consumed is unlikely to induce any negative effects or develop toxicity in humans. The use of riboflavin in pharmaceutical and clinical contexts has been previously explored, including for preventing and treating oxidative stress and reperfusion oxidative damage, creating synergistic compounds to mitigate colorectal cancer, modulating blood pressure, improving diabetes mellitus comorbidities, as well as neuroprotective agents and potent photosensitizer in killing bloodborne pathogens. Thus, the goal of this review is to provide a comprehensive understanding of riboflavin's biological applications in medicine, key considerations of riboflavin safety and toxicity, and a brief overview on the nanoencapsulation of riboflavin for various functions including the treatment of a range of diseases, photodynamic therapy, and cellular imaging. Riboflavin (Vitamin B 2) is an essential nutrient and important in the prevention and treatment of a wide range of diseases. This review provides an overview on the role of riboflavin in the regulation of human health and metabolic processes and discusses the key points of riboflavin (RF) safety and toxicity, and potential of RF nanoparticles as photoactivatable agents in photodynamic therapy (PDT) and molecular cell imaging applications. The graphical abstract was created using BioRender illustration tool, accessed at https://www.biorender.com. [Display omitted] [ABSTRACT FROM AUTHOR]

Yogurt represent one of the oldest fermented foods containing viable lactic acid bacteria and many bioactive compounds that could exhibit beneficial effects on human health and train our immune system to better respond to invading pathogens. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus are commonly used for yogurt preparation under controlled temperature and environmental conditions. In this study, we investigated probiotic features of S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains isolated from artisanal sour milk and yogurt by using Caenorhabditis elegans as an in vivo model system. Further, we evaluated content of total fat, saturated fatty acids, proteins, and lactose, as well as vitamins and AA of yogurt prepared from above-mentioned starter cultures during 21 d of storage at 4°C to get insights of final product stability. We showed that S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains applied in combination upregulated the expression of autophagy-related genes in C. elegans. Beside autophagy, we observed activation of TIR-1-dependent transcription of lysozyme-like antimicrobial genes involved in the immune defense of C. elegans. Upregulation of these genes strongly correlates with an increase in the longevity of the worms fed with yogurt culture bacteria. Further, we showed that yogurt prepared with S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21, as a final product, is rich with vitamin B 2 and dominant AA known by their prolongevity properties. Taken together, our study pointed to the beneficial features of the tested starter cultures and yogurt and highlighted their potential to be used as a fermented food with added-value properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Coenzymes are important for all classes of enzymatic reactions and essential for cellular metabolism. Most coenzymes are synthesized from dedicated precursors, also referred to as vitamins, which prototrophic bacteria can either produce themselves from simpler substrates or take up from the environment. The extent to which prototrophs use supplied vitamins and whether externally available vitamins affect the size of intracellular coenzyme pools and control endogenous vitamin synthesis is currently largely unknown. Here, we studied coenzyme pool sizes and vitamin incorporation into coenzymes during growth on different carbon sources and vitamin supplementation regimes using metabolomics approaches. We found that the model bacterium Escherichia coli incorporated pyridoxal, niacin, and pantothenate into pyridoxal 50-phosphate, NAD, and coenzyme A (CoA), respectively. In contrast, riboflavin was not taken up and was produced exclusively endogenously. Coenzyme pools were mostly homeostatic and not affected by externally supplied precursors. Remarkably, we found that pantothenate is not incorporated into CoA as such but is first degraded to pantoate and β- alanine and then rebuilt. This pattern was conserved in various bacterial isolates, suggesting a preference for β-alanine over pantothenate utilization in CoA synthesis. Finally, we found that the endogenous synthesis of coenzyme precursors remains active when vitamins are supplied, which is consistent with described expression data of genes for enzymes involved in coenzyme biosynthesis under these conditions. Continued production of endogenous coenzymes may ensure rapid synthesis of the mature coenzyme under changing environmental conditions, protect against coenzyme limitation, and explain vitamin availability in naturally oligotrophic environments. [ABSTRACT FROM AUTHOR]

Photooxidation has long been affecting nutrient and sensory quality of fluid milk. Light oxidation starts from the activation of photosensitive compounds, followed by generation of singlet oxygen that reacts with vitamins, proteins, and lipids in milk. It is hypothesized that wavelength-tailored light schemes possessing spectral properties capable of avoiding excitation maxima of common photosensitizers in milk could slow the chemical degradation of light-exposed milk and thus preserve consumer acceptability. A series of 6 consumer tests with sample sizes from 95 to 119 participants tested hedonic responses to fluid milk samples exposed to light of varying wavelength spectra. For milk in clear plastic bottles (polyethylene terephthalate or high-density polyethylene), consumer panels generally liked milk exposed to light-emitting diodes eliminating wavelengths below 520 or 560 nm more than standard white light, or those eliminating other wavelength bands. This higher degree of liking coincided with panelists citing fewer off-flavors or aromas from these samples. Taken together, these observations suggest such light schemes can protect milk from light damage to some extent. Wavelength-tailored light schemes used in this study did not offer effective protection for milk in glass bottles. Dissolved oxygen, color, riboflavin loss, and hexanal content were instrumentally evaluated, but results failed to indicate significant signatures of light damage in milk compared with sensory measures. The appearance of milk bottles illuminated by the slightly greenish or yellowish light were less liked by consumers, suggesting further efforts on consumer education may be necessary if these light schemes were to be installed in retail dairy coolers. [ABSTRACT FROM AUTHOR]

To determine whether a combined myo-inositol, probiotics and micronutrient nutritional supplement impacts time-to-natural-conception and clinical pregnancy rates. Secondary outcomes of a double-blind randomized controlled trial. Community recruitment. Women aged 18 to 38 years planning to conceive in the United Kingdom, Singapore, and New Zealand, excluding those with diabetes mellitus or receiving fertility treatment. A standard (control) supplement (folic acid, iron, calcium, iodine, β-carotene), compared with an intervention additionally containing myo-inositol, probiotics, and other micronutrients (vitamins B2, B6, B12, D, zinc). Number of days between randomization and estimated date of natural conception of a clinical pregnancy, as well as cumulative pregnancy rates at 3, 6, and 12 months. Of 1729 women randomized, 1437 (83%; intervention, n=736; control, n=701) provided data. Kaplan-Meier curves of conception were similar between intervention and control groups; the time at which 20% achieved natural conception was 90.5 days (95% confidence interval: 80.7, 103.5) in the intervention group compared with 92.0 days (76.0, 105.1) in the control group. Cox's proportional hazard ratios (HRs) comparing intervention against control for cumulative achievement of pregnancy (adjusted for site, ethnicity, age, body mass index, and gravidity) were similar at 3, 6, and 12 months. Among both study groups combined, overall time-to-conception lengthened with higher preconception body mass index, and was longer in non-White than in White women. Among women who were overweight the intervention shortened time-to-conception compared with control regardless of ethnicity (12-month HR=1.47 [1.07, 2.02], P =.016; 20% conceived by 84.5 vs. 117.0 days) and improved it to that comparable to nonoverweight/nonobese women (20% conceived by 82.1 days). In contrast, among women with obesity, time-to-conception was lengthened with intervention compared with control (12-month HR=0.69 [0.47, 1.00]; P =.053; 20% conceived by 132.7 vs. 108.5 days); an effect predominantly observed in non-White women with obesity. Time-to-natural-conception and clinical pregnancy rates within a year were overall similar in women receiving the intervention supplement compared with control. Overweight women had a longer time-to-conception but there was suggestion that the supplement may shorten their time-to-conception to that comparable to the nonoverweight/nonobese women. Further studies are required to confirm this. clinicaltrials.gov (NCT02509988) [ABSTRACT FROM AUTHOR]

Globally, ruminant production systems used to synthesize meat and milk differ tremendously in terms of their efficiency, productivity, and environmental impacts. Regardless of this variability, milk has been repeatedly identified as an essential source of nutrients for humans. The objective of this work was to characterize global contributions of fluid milk to human food and nutrient supplies, greenhouse gas emissions, and water withdrawal. Data were leveraged from the United Nations Food and Agriculture Organization to estimate global supplies of agricultural products. Trade of agricultural products and waste of those products, along with use of human food for livestock feed were accounted for before estimating human nutrient supplies. The contributions of milk to human-edible nutrient supplies were then enumerated in terms of their proportion of total nutrients supplied by the agricultural system and in terms of the human population's requirement for that nutrient. We identified that fluid milk provides over 10% of consumable supplies of vitamin B 12 , vitamin A, riboflavin, and calcium available for humans globally. In terms of human nutrient requirements, milk provides sufficient vitamin B 12 to meet the needs of over 60% of the global population, riboflavin to satisfy 50% of the population, and calcium and phosphorus for over 35% of the population. Compared with other foods, milk ranked among the highest in terms of nutrient-to-calorie ratio for numerous amino acids, phosphorus, calcium, and riboflavin. Conditional dependencies were identified between greenhouse gas emissions and ruminant milk and meat, but not between water withdrawal and milk production. When evaluating the trade-offs in nutrient use versus nutrient provision for producing milk or producing all ruminant products, the production of ruminants worldwide was associated with both net increases and net decreases of several key nutrients. Continued work focusing on strategies to reduce the environmental impact of milk production will improve the utility of milk for feeding the growing global population. [ABSTRACT FROM AUTHOR]

Due to the delayed and vague symptoms, it is difficult to early diagnose mesenteric ischemia injuries in the dynamics of acute illness, leading to a 60–80 % mortality rate. Here, we found plasma fluorescence spectra can rapidly assess the severity of mesenteric ischemia injury in animal models. Ischemia-reperfusion damage of the intestine leads to multiple times increase in NADH, flavins, and porphyrin auto-fluorescence of blood. The fluorescence intensity ratio between blue-fluorophores and flavins can reflect the occurrence of shock. Using liquid chromatography and mass spectroscopy, we confirm that riboflavin is primarily responsible for the increased flavin fluorescence. Since humans absorb riboflavin from the intestine, its increase in plasma may indicate intestinal mucosa injury. Our work suggests a self-calibrated and reagent-free approach to identifying the emergence of fatal mesenteric ischemia in emergency departments or intensive care units. [ABSTRACT FROM AUTHOR]

CXXC5, a member of the CXXC family of zinc-finger proteins, is associated with numerous pathological processes. However, the pathophysiological function of CXXC5 has not been clearly established. Herein, we found that CXXC5 interacts with the CRL4B and NuRD complexes. Screening of transcriptional targets downstream of the CXXC5--CRL4B--NuRD complex by next-generation sequencing (chromatin immunoprecipitation sequencing) revealed that the complex regulates the transcriptional repression process of a cohort of genes, including TSC1 (tuberous sclerosis complex subunit 1), which play important roles in cell growth and mammalian target of rapamycin signaling pathway regulation, and whose abnormal regulation results in the activation of programmed cell death--ligand protein 1 (PD-L1). Intriguingly, CXXC5 expression increased after stimulation with vitamin B2 but decreased after vitamin D treatment. We also found that the CXXC5--CRL4B--NuRD complex promotes the proliferation of tumor cells in vitro and accelerates the growth of breast cancer in vivo. The expression of CXXC5, CUL4B, and MTA1 increased during the occurrence and development of breast cancer, and correspondingly, TSC1 expression decreased. Meanwhile, a high expression of CXXC5 was positively correlated with the histological grade of high malignancy and poor survival of patients. In conclusion, our study revealed that CXXC5-mediated TSC1 suppression activates the mammalian target of rapamycin pathway, reduces autophagic cell death, induces PD-L1-mediated immune suppression, and results in tumor development, shedding light on the mechanism of the pathophysiological function of CXXC5. [ABSTRACT FROM AUTHOR]

The compound 3-nitrooxypropanol (3-NOP) is a promising methane inhibitor, which performs well in inhibiting methane emission and does not affect animal feed intake and digestibility. However, it causes a significant increase in hydrogen production while suppressing methane emission, resulting in a waste of feed energy. Vitamin B 12 is a key factor in the propionate production pathway and thus plays an important role in regulating the hydrogen utilization pathway. In this study, the effects of 3-NOP combined with vitamin B 12 supplementation on rumen fermentation and microbial compositional structure in dairy cattle were investigated by simulating rumen fermentation in vitro. Experiments were performed using a 2 × 2-factorial design: two 3-NOP levels (0 or 2 mg/g dry matter) and 2 vitamin B 12 levels (0 or 2 mg/g dry matter). Three experiments were performed, each consisting of 4 treatments, 4 replicates, and 4 blanks containing only inoculum. The combined supplementation of 3-NOP and vitamin B 12 reduced methane emission by 12% without affecting dry matter digestibility. The combined addition of 3-NOP and vitamin B 12 significantly increased the concentration of propionate and reduced the concentration of acetate and the acetate to propionate ratio. At the bacterial level, 3-NOP increased the relative abundances of Christensenellaceae_R-7_group and Lachnospiraceae_NK3A20_group. Vitamin B 12 increased the relative abundances of unclassified_f__Prevotellaceae and Prevotellaceae_UCG-003 and decreased the relative abundance of Lachnospiraceae_NK3A20_group. At the archaeal level, the combination of 3-NOP and vitamin B 12 increased the relative abundances of Methanobrevibacter_ sp._ Abm4 , OTU1125, and OTU95 and decreased the relative abundances of uncultured_methanogenic_archaeon_g__Methanobrevibacter , OTU1147, OTU1056, and OTU55. The results indicated that 3-NOP combined with vitamin B 12 could alleviate rumen hydrogen emission and enhance the inhibition of methane emission compared with 3-NOP alone. [ABSTRACT FROM AUTHOR]

Cold-set interpenetrating polymer network gels as riboflavin (RF) delivery vehicles based on wheat bran arabinoxylans (AX) and pea protein isolate (PPI) were developed via enzymatic-crosslinking. The impact of AX concentrations on the physicochemical property, in vitro digestion property and microstructure of IPN gels was explored. Increased concentrations of AX enhanced the viscoelasticity of IPN gels and resulted in a more compact microstructure. However, at a concentration of 5.0 % (w / v), the faster and stronger crosslinking of AX molecules caused separate network gel between PPI and AX. The IPN gel improved the encapsulation efficiency and release property of embedded RF as compared to PPI gel. SEM results showed that IPN gel maintained a complete network structure after gastric digestion. Particularly, the IPN gel with 1.0 % AX exhibited a homogeneous and complete network structure even after intestinal digestion, which explained the reason for the highest encapsulation efficiency and lowest release ratios of RF. [Display omitted] • IPN gels based on arabinoxylans and pea protein isolate were prepared via enzymatic crosslinking. • The IPN structure improved the rheological properties and water mobility of gel samples. • AX could protect PPI gel from faster degradation during in vitro digestion. • IPN gel prepared with 1.0 wt% AX showed huge potential as delivery vehicles for riboflavin. [ABSTRACT FROM AUTHOR]

Extracellular hydrolysis of flavin-adenine dinucleotide (FAD) and flavin mononucleotide (FMN) to riboflavin is thought to be important for cellular uptake of vitamin B2 because FAD and FMN are hydrophilic and do not pass the plasma membrane. However, it is not clear whether FAD and FMN are hydrolyzed by cell surface enzymes for vitamin B2 uptake. Here, we show that in human cells, FAD, a major form of vitamin B2 in plasma, is hydrolyzed by CD73 (also called ecto-5' nucleotidase) to FMN. Then, FMN is hydrolyzed by alkaline phosphatase to riboflavin, which is efficiently imported into cells. We determined that this two-step hydrolysis process is impaired on the surface of glycosylphosphatidylinositol (GPI)- deficient cells due to the lack of these GPI-anchored enzymes. During culture of GPI-deficient cells with FAD or FMN, we found that hydrolysis of these forms of vitamin B2 was impaired, and intracellular levels of vitamin B2 were significantly decreased compared with those in GPI-restored cells, leading to decreased formation of vitamin B2-dependent pyridoxal 50 -phosphate and mitochondrial dysfunction. Collectively, these results suggest that inefficient uptake of vitamin B2 might account for mitochondrial dysfunction seen in some cases of inherited GPI deficiency. [ABSTRACT FROM AUTHOR]

Background The generation of the active form of vitamin B-6, pyridoxal 5′-phosphate (PLP), in tissues is dependent upon riboflavin as flavin mononucleotide, but whether this interaction is important for maintaining vitamin B-6 status is unclear. Objective To investigate vitamin B-6 and riboflavin status, their metabolic interaction, and relationship with methylenetetrahydrofolate reductase (MTHFR) genotype in adulthood. Methods Data from 5612 adults aged 18–102 y were drawn from the Irish National Adult Nutrition Survey (NANS; population-based sample) and the Trinity-Ulster Department of Agriculture (TUDA) and Genovit cohorts (volunteer samples). Plasma PLP and erythrocyte glutathione reductase activation coefficient (EGRac), as a functional indicator of riboflavin, were determined. Results Older (≥65 y) compared with younger (<65 y) adults had significantly lower PLP concentrations (P  < 0.001). A stepwise decrease in plasma PLP was observed across riboflavin categories, from optimal (EGRac ≤1.26), to suboptimal (EGRac: 1.27–1.39), to deficient (EGRac ≥1.40) status, an effect most pronounced in older adults (mean ± SEM: 76.4 ± 0.9 vs 65.0 ± 1.1 vs 55.4 ± 1.2 nmol/L; P  < 0.001). In individuals with the variant MTHFR 677TT genotype combined with riboflavin deficiency, compared with non-TT (CC/CT) genotype participants with sufficient riboflavin, we observed PLP concentrations of 52.1 ± 2.9 compared with 76.8 ±0.7 nmol/L (P  < 0.001). In participants with available dietary data (i.e. NANS cohort, n = 936), PLP was associated with vitamin B-6 intake (nonstandardized regression coefficient β: 2.49; 95% CI 1.75, 3.24; P  < 0.001), supplement use (β: 81.72; 95% CI: 66.01, 97.43; P  < 0.001), fortified food (β: 12.49; 95% CI: 2.08, 22.91; P  = 0.019), and EGRac (β: –65.81; 95% CI: –99.08, –32.54; P  < 0.001), along with BMI (β: –1.81; 95% CI: –3.31, –0.30; P  = 0.019). Conclusions These results are consistent with the known metabolic dependency of PLP on flavin mononucleotide (FMN) and suggest that riboflavin may be the limiting nutrient for maintaining vitamin B-6 status, particularly in individuals with the MTHFR 677TT genotype. Randomized trials are necessary to investigate the PLP response to riboflavin intervention within the dietary range. The TUDA study and the NANS are registered at www.ClinicalTrials.gov as NCT02664584 (27 January 2016) and NCT03374748 (15 December 2017), respectively. Clinical Trial Registry details: Trinity-Ulster-Department of Agriculture (TUDA) study, ClinicalTrials.gov no. NCT02664584 (January 27th 2016); National Adult Nutrition Survey (NANS), ClinicalTrials.gov no. NCT03374748 (December 15th 2017). [ABSTRACT FROM AUTHOR]

Riboflavin transporter deficiency is a rare but severe neurometabolic disorder. We report two siblings with pathogenic variants in SLC52A3 gene, resulting in riboflavin transporter 3 deficiency. The first sibling was diagnosed at age 11 months with severe respiratory compromise and regression of developmental milestones. His symptoms significantly improved with riboflavin supplementation therapy. The younger sibling was diagnosed by antenatal genetic analysis; riboflavin supplementation was initiated in utero and continued from birth. Now at age two years, he remains clinically asymptomatic despite genetic confirmation of riboflavin transporter deficiency. Antenatal riboflavin supplementation is a safe and effective treatment for the prevention of symptomatic manifestations of riboflavin transporter deficiency. [ABSTRACT FROM AUTHOR]

Riboflavin is a redox-active vitamin that plays a pivotal role in human energy metabolism. Riboflavin may have beneficial health effects by increasing extracellular antioxidant capacity, thereby alleviating oxidative stress. Reduced levels of free thiols in blood reflect systemic oxidative stress, since they are readily oxidized by reactive species. In this study, we aimed to study the potential of riboflavin supplementation to improve the systemic redox status in healthy volunteers. This study was a post-hoc analysis of the RIBOGUT study, a randomized, double-blind, placebo-controlled human intervention trial that investigated the effect of riboflavin supplements on the gut microbiota composition of healthy individuals. Serum free thiols were quantified before and after intervention and adjusted to serum albumin levels. Changes in albumin-adjusted free thiols were analyzed, as well as potential associations with routine laboratory parameters and faecal bacterial quantification by fluorescence in-situ hybridization (FISH). Participants were randomized to either placebo (n = 34), riboflavin 50 mg daily (n = 32), or riboflavin 100 mg daily (n = 33). At baseline, no significant differences in albumin-adjusted serum free thiols were observed. After intervention with either placebo or riboflavin, albumin-adjusted serum free thiols did not significantly change (P > 0.05), however, observed changes were inversely associated with changes in C-reactive protein (CRP) levels (r = −0.22, P < 0.05). At baseline, albumin-adjusted serum free thiols were positively associated with faecal relative abundances of Faecalibacterium prausnitzii (P < 0.01). Riboflavin did not change the systemic redox status in healthy individuals as reflected by serum free thiols, but observed changes in albumin-adjusted free thiol levels were negatively associated with changes in CRP levels. Strikingly, albumin-adjusted free thiols were independently associated with relative abundances of faecal F. prausnitzii , which may suggest a potential host redox-microbiota interaction. [Display omitted] • Riboflavin (vitamin B 2) has anti-inflammatory and antioxidant properties. • Serum free sulfhydryl groups (R–SH) reflect whole-body redox status in health and disease. • Riboflavin may beneficially modulate redox status as reflected by R–SH. • Riboflavin supplementation does not impact serum R–SH in healthy volunteers. • Effects of riboflavin on other redox status components warrant further investigation. [ABSTRACT FROM AUTHOR]

Biosynthesis of riboflavin (RF), the precursor of the redox cofactors FMN and FAD, was thought to be well understood in bacteria, with all the pathway enzymes presumed to be known and essential. Our previous research has challenged this view by showing that, in the bacterium Sinorhizobium meliloti, deletion of the ribBA gene encoding the enzyme that catalyzes the initial steps on the RF biosynthesis pathway only causes a reduction in flavin secretion rather than RF auxotrophy. This finding led us to hypothesize that RibBA participates in the biosynthesis of flavins destined for secretion, whereas S. meliloti has another enzyme that performs this function for internal cellular metabolism. Here, we identify and biochemically characterize a novel formamidase (SMc02977) involved in the production of RF for intracellular functions in S. meliloti. This catalyst, which we named Sm-BrbF, releases formate from the early RF precursor 2-amino-5-formylamino-6- ribosylamino-4(3H)-pyrimidinone 5'-phosphate to yield 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate. We show that homologs of this enzyme are present in many bacteria, are highly abundant in the Rhizobiales order, and that sequence homologs from Brucella abortus and Liberobacter solanacearum complement the RF auxotrophy of the Sm1021ΔSMc02977 mutant. Furthermore, we show that the B. abortus enzyme (Bab2&lowbar;0247, Ba-BrbF) is also an 2-amino-5-formylamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate formamidase, and that the bab2&lowbar;0247 mutant is a RF auxotroph exhibiting a lower level of intracellular infection than the wildtype strain. Finally, we show that Sm-BrbF and Ba-BrbF directly interact with other RF biosynthesis pathway enzymes. Together, our results provide novel insight into the intricacies of RF biosynthesis in bacteria. [ABSTRACT FROM AUTHOR]

The ion-pumping NQR complex is an essential respiratory enzyme in the physiology of many pathogenic bacteria. This enzyme transfers electrons from NADH to ubiquinone through several cofactors, including riboflavin (vitamin B2). NQR is the only enzyme reported that is able to use riboflavin as a cofactor. Moreover, the riboflavin molecule is found as a stable neutral semiquinone radical. The otherwise highly reactive unpaired electron is stabilized via an unknown mechanism. Crystallographic data suggested that riboflavin might be found in a superficially located site in the interface of NQR subunits B and E. However, this location is highly problematic, as the site does not have the expected physiochemical properties. In this work, we have located the riboflavin-binding site in an amphipathic pocket in subunit B, previously proposed to be the entry site of sodium. Here, we show that this site contains absolutely conserved residues, including N200, N203, and D346. Mutations of these residues decrease enzymatic activity and specifically block the ability of NQR to bind riboflavin. Docking analysis and molecular dynamics simulations indicate that these residues participate directly in riboflavin binding, establishing hydrogen bonds that stabilize the cofactor in the site. We conclude that riboflavin is likely bound in the proposed pocket, which is consistent with enzymatic characterizations, thermodynamic studies, and distance between cofactors. [ABSTRACT FROM AUTHOR]

Direct interspecies electron transfer systems of acetoclastic and hydrogenotrophic methanogens with Geobacter metallireducens have been successfully established. However, the effects of riboflavin (RF) on these cocultures are not yet known. This study established two syntrophic cocultures with RF, acetoclastic Methanosarcina mazei and hydrogenotrophic Methanobacterium sp. YSL with G. metallireducens , and compared their transcriptome profiles. The results showed that a shorter start-up time lag of Methanobacterium sp. YSL was accompanied by unique transcriptome profiles when RF was added. Furthermore, the differential expression of key genes involved in the pathways was analyzed by comparative transcriptomics. Different proposed methanogenic pathways in the coculture systems were activated by M. mazei and Methanobacterium sp. YSL with RF. The earlier start-up of Methanobacterium sp. YSL cocultures was closely related to the overexpression of the gene encoding methyl-coenzyme M reductase (Mcr II) initiated by RF. The results revealed the distinct transcriptome profiles of acetoclastic and hydrogenotrophic methanogens accepting electrons from Geobacter mediated by RF, indicating the selective facilitation of the electron acceptance of methanogens and shedding new light on the fast start-up of anaerobic digesters for wastewater treatment. [ABSTRACT FROM AUTHOR]

The article discusses a riboflavin evidence scan to update the riboflavin dietary reference intakes (DRI). Topics covered include components of the evidence scan, the processes involved, the reports on adequacy and chronic disease outcomes, and the limitations identified of studies that lead to exclusion. Also noted is the scan's identification of 35 studies that could be used for a future DRI committee for a full systematic review.

Epidemiological evidence indicates that exposure to halogenated polycyclic aromatic hydrocarbons (HPAHs) is associated with many adverse effects. However, the mechanisms of metabolic disorder of HPAHs remains limited. Herein, effects of pyrene (Pyr), and its halogenated derivatives (1-chloropyrene (1-Cl-Pyr), 1-bromopyrene (1-Br-Pyr)) on endogenous metabolic pathways were investigated, in human hepatoma (HepG2) and HepG2-derived cell lines expressing various human cytochrome P450s (CYPs). Non-targeted metabolomics results suggested that 1-Br-Pyr and Pyr exposure (625 nM) induced disruption in glutathione and riboflavin metabolism which associated with redox imbalance, through abnormal accumulation of oxidized glutathione, mediated by bioactivation of CYP2E1. Conversely, CYP2C9-mediated 1-Cl-Pyr significantly interfered with glutathione metabolism intermediates, including glycine, L-glutamic acid and pyroglutamic acid. Notably, CYP1A1-mediated Pyr-induced perturbation of amino acid metabolism which associated with nutrition and glycolipid metabolism, resulting in significant upregulation of most amino acids, whereas halogenated derivatives mediated by CYP1A2 substantially downregulated amino acids. In conclusion, this study suggested that Pyr and its halogenated derivatives exert potent effects on endogenous metabolism disruption under the action of various exogenous metabolic enzymes (CYPs). Thus, new evidence was provided to toxicological mechanisms of HPAHs, and reveals potential health risks of HPAHs in inducing diseases caused by redox and amino acid imbalances. [Display omitted] • HepG2-derived cell lines express 6 CYPs were developed for metabolomics studies. • 1-Cl-Pyr and 1-Br-Pyr exert potent cytotoxicity compare to parent compound Pyr. • 1-Cl-Pyr and 1-Br-Pyr induced metabolic disruptions in CYPs overexpressing cells. • 1-Cl-Pyr and 1-Br-Pyr disturb glutathione metabolism mediated by different CYPs. • Opposite trends of amino acid disorders induced by Pyr and halogenated derivatives. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fluorescence of VB 2 quenched by MnO 2 NSs was revealed. • VB 2 -MnO 2 NSs could be used as a probe for acid phosphatase fluorescence detection. • The method exhibited excellent sensitivity and high selectivity. Fluorescence analysis has attracted much attention due to its rapidity and sensitivity. The present work describes a novel fluorescence detection method for acid phosphatase (ACP) on the basis of inner-filter effect (IFE), where MnO 2 nanosheets (MnO 2 NSs) and vitamin B 2 (VB 2) are served as absorbers and fluorophores, respectively. In the absence of ACP, the absorption band of MnO 2 NSs overlaps well with the excitation band of VB 2 , resulting in effective IFE and inhibition of VB 2 fluorescence. In the presence of ACP, 2-phospho-L-ascorbic acid trisodium salt (AAP) is hydrolyzed to generate ascorbic acid (AA), which efficiently trigger the reduction of MnO 2 NSs into Mn2+ ions, causing the weakening of the MnO 2 NSs absorption band and the recovery of VB 2 fluorescence. Further investigation indicates that the fluorescence recovery degree of VB 2 increases with the increase of ACP concentration. Under selected experimental conditions, the proposed method can achieve sensitive detection of ACP in the ranges of 0.5–4.0 mU/mL and 4.0–15 mU/mL along with a limit of detection (LOD) as low as 0.14 mU/mL. Finally, this method was successfully applied for the detection of ACP in human serum samples with satisfactory recoveries in the range of 95.0 %-108 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propolis from Trancas (ProTr) has a high capacity to remove reactive oxygen species (ROS). • ProTr has an antioxidant action akin to that of the well-known antioxidant Trolox. • Kinetic study on the interactions of Riboflavin (Rf) and Rose Bengal (RB)-photogenerated ROS with propolis. • ProTr presents a viable natural substitute for synthetic antioxidants in the fight against oxidative stress. • ProTr degradation occurs through excited states of Rf and ROS photogenerated. This study focused on the scavenging action and antioxidant activity of propolis from Trancas (ProTr) as a promoter and scavenger of Riboflavin (Rf)-photogenerated reactive oxygen species (ROS), widely used in traditional medicine as an antioxidant. A thorough examination of the antioxidant activity of ethanolic extract (EE) was made possible by a kinetic and mechanistic study of the total polyphenol contents in the extract using stationary photolysis and time-resolved photochemical methods. Under aerobic visible-light-irradiation conditions, with Rf as the only light-absorber molecule, a complex frame of competitive interactions takes place, with the triplet excited states of Rf being quenched by ProTr. Rf triplet excited states can interact with ProTr or produce singlet oxygen and superoxide radical anions. The results indicated ProTr to be an efficient ROS scavenger. The antioxidant behavior of ProTr is similar to that of Trolox, a well-known antioxidant. Propolis is slightly photodegraded by interaction with the mentioned ROS, highlighting the crucial role of ProTr and its potential in mitigating oxidative stress-induced damage in biological systems. These findings suggest that ProTr could be a promising natural alternative to synthetic antioxidants for combating oxidative stress. [ABSTRACT FROM AUTHOR]

The application of many hydrophilic and hydrophobic nutraceuticals is limited by their poor solubility, chemical stability, and/or bioaccessibility. In this study, a novel Pickering high internal phase double emulsion co-stabilized by modified pea protein isolate (PPI) and sodium alginate (SA) was developed for the co-encapsulation of model hydrophilic (riboflavin) and hydrophobic (β-carotene) nutraceuticals. Initially, the effect of emulsifier type in the external water phase on emulsion formation and stability was examined, including commercial PPI (C-PPI), C-PPI-SA complex, homogenized and ultrasonicated PPI (HU-PPI), and HU-PPI-SA complex. The encapsulation and protective effects of these double emulsions on hydrophilic riboflavin and hydrophobic β-carotene were then evaluated. The results demonstrated that the thermal and storage stabilities of the double emulsion formulated from HU-PPI-SA were high, which was attributed to the formation of a thick biopolymer coating around the oil droplets, as well as thickening of the aqueous phase. Encapsulation significantly improved the photostability of the two nutraceuticals. The double emulsion formulated from HU-PPI-SA significantly improved the in vitro bioaccessibility of β-carotene, which was mainly attributed to inhibition of its chemical degradation under simulated acidic gastric conditions. The novel delivery system may therefore be used for the development of functional foods containing multiple nutraceuticals. [Display omitted] • A hydrophilic emulsifier was synthesized by using modified PPI and SA. • HU-PPI-SA complex enhanced the stability of the high internal phase W/O/W emulsion. • The W/O/W emulsion achieved co-encapsulation of riboflavin and β-carotene. [ABSTRACT FROM AUTHOR]

High-dimensional feature selection is of particular interest to researchers. In some domains, such as microarray data, it is quite common for a group of highly correlated explanatory variables to be of equal importance for inclusion in the predictive model. This paper proposes a new hybrid feature selection approach that integrates feature screening based on Kendall's tau and Elastic Net regularized regression (K -EN). K -EN as an approach that embeds the Elastic Net, has the advantage of the grouping effect, which automatically includes all the highly correlated variables in the group. The K -EN approach offers insightful solutions to high-dimensional regression problems and improves Elastic Net performance since the screening phase is preceded by a step that further reduces the number of explanatory variables by removing those that disagree with the target based on Kendall's tau. The use of Kendall's tau further enhances Elastic Net performance, as it is robust enough to handle heavy-tailed distributions, non-parametric models, outliers, and non-normal data with greater ease. K -EN is therefore a time-saving approach. The proposed algorithm is evaluated on four simulation scenarios and four publicly available datasets, including riboflavin, eyedata, Longley, and Boston Housing, and achieves 0.2528, 0.0098, 0.1007, and 0.4121 respectively as the Mean Squared Error (MSE). K -EN's MSEs are the best compared to those achieved by the state-of-the-art approaches reviewed in this paper. In addition, K -EN selects up to 100% of relevant features when run on simulated data. [ABSTRACT FROM AUTHOR]

The synthesis of 1 @cotton fabric composite for the colorimetric response towards the recognition of antibiotic NZF and NFT and the biomarker riboflavin (RBF). [Display omitted] • Fluorescent Zn based MOF and its MOF@cotton composite were synthesized. • Sensor showed the ratiometric detection of biomarker vitamin B2 in aqua medium. • Sensor showed the detection of antibiotic in aqua medium. • K SV , anti-interference, rapid response and LOD for these analytes were determined. • The sensing mechanism was rationalized by PET, FRET, IFE and further DFT study. • Sensor showed the detection of biomarker and antibiotic in diverse environmental samples. Here, we demonstrated the synthesis of a zinc based luminescent MOF, 1 (NDC = 2,6- naphthalenedicarboxylate) for the ratiometric detection of biomarker riboflavin (RBF; vitamin B 2) in water dispersed medium. Further, this MOF detected two other antibiotic drug molecules, nitrofurantoin (NFT) and nitrofurazone (NZF). The detection of these analytes is very quick (∼seconds), and the limit of detection (LOD) for RBF, NZF and NFT are calculated as 16.58 ppm, 47.63 ppb and 56.96 ppb, respectively. The detection of these analytes was also comprehended by solid, solution, cost-effective paper strip method i.e., triphasic identification capabilities. The sensor is reusable without losing its detection efficacy. The sensor further showed the recognition abilities of these antibiotics in real field samples (river water, urine and tablet) and RBF in vitamin B 2 pills and food samples (milk and cold drinks). The sensing merit of 1 urged us to fabricate of 1 @cotton fabric composite, which exhibited the colorimetric detection of these analytes. In-depth experimental analysis suggested that the occurrence of photo-induced electron transfer (PET), fluorescence resonance energy transfer (FRET), and the inner filter effect (IFE) are the possible sensing mechanisms for the recognition of the antibiotics drug. The FRET mechanism is responsible for the recognition of RBF. The sensing mechanism is further supported by the theoretical analysis and the excited lifetime measurement. [ABSTRACT FROM AUTHOR]

[Display omitted] • A poly(dopamine) modified carbon paste electrode was designed to detect rutin (RT) using voltammetric technique. • The DA film increased the sensitivity of the bare electrode towards RT, the electrocatalytic activity of the sensor was confirmed by CV and EIS study. • The PDAMCPE follows adsorption-controlled process during the electrochemical reaction of RT. • The modified electrode exhibited good repeatability, reproducibility and stability. • PDAMCPE showed good recovery rate when examined in real samples like green tea and tablet sample. In this work, a sensor was developed for the quantification of RT in food and medicine samples using electro-polymerization of dopamine (DA) on the surface of a carbon paste electrode in 0.2 M phosphate buffered saline (PBS) of 7.0 pH by cyclic voltammetry (CV). The surface properties of bare carbon paste electrode (BCPE) and poly (DA) modified carbon paste electrode (PDAMCPE) were studied using scanning electron microscopy (SEM), electrochemical impedance study (EIS), and CV techniques. Two electron two proton transfer process was seen during the electrochemical reaction of RT with adsorption-controlled process. Under optimum conditions, the peak current increased linearly with an increase in RT concentration for CV in the range of 0.4 to 2.0 μM and differential pulse voltammetry (DPV) in the range of 0.4 to 2.5 μM and the limit of detection (LOD) was found to be 0.0045 μΜ and for CV and 0.079 μM for DPV techniques respectively. Even in the presence of some interferents like organic compounds and metal ions, the developed electrode exhibits good anti-interference ability for RT, and good selectivity was obtained for RT in the presence of riboflavin (RF). The developed sensor presents good stability, repeatability, and reproducibility. The CV measurement was performed for the analysis of RT in real samples such as green tea and medicine samples which showed a good recovery and this work has been not reported previously. [ABSTRACT FROM AUTHOR]

• Nitrate reduction coupled with Ni oxidation is thermodynamically favorable. • Ni corrosion is more severe in carbon starvation than the full-strength medium. • Riboflavin enhances the biocatalytic activity of P. aeruginosa biofilm. • EET is responsible for the accelerated corrosion of Ni by P. aeruginosa. • Data provide support for Ni EET-MIC with electron uptake by Ni oxidation. The primary objective of this study is to elucidate the synergistic effect of an exogenous redox mediator and carbon starvation on the microbiologically influenced corrosion (MIC) of metal nickel (Ni) by nitrate reducing Pseudomonas aeruginosa. Carbon source (CS) starvation markedly accelerates Ni MIC by P. aeruginosa. Moreover, the addition of exogenous riboflavin significantly decreases the corrosion resistance of Ni. The MIC rate of Ni (based on corrosion loss volume) is ranked as: 10 % CS level + riboflavin > 100 % CS level + riboflavin > 10 % CS level > 100 % CS level. Notably, starved P. aeruginosa biofilm demonstrates greater aggressiveness in contributing to the initiation of surface pitting on Ni. Under CS deficiency (10 % CS level) in the presence of riboflavin, the deepest Ni pits reach a maximum depth of 11.2 μm, and the corrosion current density (i corr) peak at approximately 1.35 × 10−5 A·cm−2, representing a 2.6-fold increase compared to the full-strength media (5.25 × 10−6 A·cm−2). For the 10 % CS and 100 % CS media, the addition of exogenous riboflavin increases the Ni MIC rate by 3.5-fold and 2.9-fold, respectively. Riboflavin has been found to significantly accelerate corrosion, with its augmentation effect on Ni MIC increasing as the CS level decreases. Overall, riboflavin promotes electron transfer from Ni to P. aeruginosa , thus accelerating Ni MIC. [ABSTRACT FROM AUTHOR]

• Self-assembled heat-induced gels had higher mechanical strength. • Hydrophobic interactions had a greater role in self-assembled heat-induced gels. • Self-assembled cold-induced gels had better water retention and dense structure. • Whether or not heat treatment is used to form gels may play a more important role. • Self-assembled cold-induced gels could effectively load bioactive substances. Based on the findings of our previous studies, a comprehensive comparative investigation of the quality and formation mechanism of gels obtained from protein self-assemblies induced by different methods is necessary. Self-assembled heat-induced gels had higher gel mechanical strength, and hydrophobic interactions played a greater role. Whether or not heat treatment was used to induce gel formation may play a more important role than the effect of divalent cations on gel formation. Hydrogen bonds played an important role in all gels formed using different gelation methods. Furthermore, Self-assembled cold-induced gels were considered to can load bioactive substances with different hydrophilicity properties due to the high water-holding capacity and the smooth, dense microstructure. Therefore, β-lactoglobulin fibrous and worm-like self-assembled cold-induced gels as a delivery material for hydrophilic bioactive substances (epigallocatechin gallate, vitamin B 2) and amphiphilic bioactive substance (naringenin), with good encapsulation efficiency (91.92 %, 97.08 %, 96.72 %, 96.52 %, 98.94 %, 97.41 %, respectively) and slow-release performance. [ABSTRACT FROM AUTHOR]

Kiwifruits are vulnerable to gray mold, and although the beneficial impacts of riboflavin on plant immunity have been acknowledged, there is a limited exploration into the influence of riboflavin photosensitization on gray mold. The impacts on gray mold susceptibility in postharvest kiwifruit were investigated at 25 °C for 8 d, and underlying mechanisms regarding oxidative stress, energy, jasmonic acid (JA), and sugars were evaluated. The morphological results showed that photosensitized riboflavin reduced the severity of gray mold. Biochemical and molecular assays indicated that riboflavin enhanced energy status, JA biosynthesis, glucose accumulation, and ameliorated oxidative stress, irrespective of photosensitization. Notably, photosensitized riboflavin exhibited three distinct effects: heightened impacts on oxidative stress and JA production; sustained electron transport chain activity without energy level increase; delayed early sucrose degradation. Collectively, these findings underscore the pivotal roles played by photosensitization-primed responses involving early stimulation of JA biosynthesis, and compromise of sucrose degradation, in enhancing resistance to gray mold in kiwifruit. • Riboflavin photosensitization benefited gray mold resistance in kiwifruit. • Oxidative stress was alleviated by the treatment. • Electron transport was maintained without increasing energy compounds. • Jasmonic acid accumulation was accelerated. • Early sucrose degradation was compromised. [ABSTRACT FROM AUTHOR]

[Display omitted] Corneal collagen crosslinking (CXL) is an effective method to halt the disease progression of keratoconus, a progressive corneal dystrophy leading to cone shaped cornea. Despite the efficacy of standard protocol, the concerning step of this procedure is epithelial debridement performed to facilitate the entry of riboflavin drug. Riboflavin, a key molecule in CXL protocol, is a sparsely permeable hydrophilic drug in corneal tissues. The present study has employed cell penetrating peptide (CPP), Tat 2 , to enhance the penetration of riboflavin molecule, and thereby improve currently followed CXL protocol. This study demonstrates approximately two-fold enhanced uptake of CPP riboflavin conjugate, Tat 2 riboflavin-5′Phosphate (RiTe conjugate), both in vitro and in vivo. Two different CXL protocols (Epi ON and Epi OFF) have been introduced and implemented in rabbit corneas using RiTe conjugate in the present study. The standard and RiTe conjugate mediated CXL procedures exhibited an equivalent extent of crosslinking in both the methods. Reduced keratocyte loss and no endothelial damage in RiTe conjugate mediated CXL further ascertains the safety of the proposed CXL protocols. Therefore, RiTe conjugate mediated CXL protocols present as potential alternatives to the standard keratoconus treatment in providing equally effective, less invasive and patient compliant treatment modality. [ABSTRACT FROM AUTHOR]

[Display omitted] Advancements in industrial technologies and the application of quality by design (QbD) guidelines are shifting the attention of manufacturers towards innovative production techniques. In the pharmaceutical field, there is a significant focus on the implementation of continuous processes, in which the production stages are carried out continuously, without the need to interrupt the process and store the production intermediates, as in traditional batch production. Such innovative production techniques also require the development of proper analytical methods able to analyze the products in-line, while still being processed. The present study aims to compare a traditional batch manufacturing process with an alternative continuous one. To this end, a real pharmaceutical formulation was used, substituting the active pharmaceutical ingredient (API) with riboflavin, at the concentration of 2 %w/w. Moreover, a direct and non-destructive analytical method based on UV–Vis reflectance spectroscopy was applied for the quantification of riboflavin in the final tablets, and compared with a traditional absorbance analysis. Good results were obtained in the comparison of both the two manufacturing processes and the two analytical methods, with R2 higher than 0.9 for all the calculated calibration models and predicted riboflavin concentrations that never significantly overcame the 15 % limits recommended by the pharmacopeia. The continuous production method demonstrated to be as reliable as the batch one, allowing to save time and money in the production step. Moreover, UV–Vis reflectance was proved to be an interesting alternative to absorption spectroscopy, which, with the proper technology, could be implemented for in-line process control. [ABSTRACT FROM AUTHOR]

Nutrition assessment is crucial for dietary guidance and prevention of malnutrition. Recent endeavors in wearable biochemical sensors have enabled real-time, in situ analysis of nutrients in sweat. However, the monitoring of riboflavin, an indispensable vitamin B involved in energy metabolism, remains challenging due to its trace level and variations in the sweat matrix. Herein, we report a wireless, battery-free, and flexible wearable biosensing system for the in situ monitoring of sweat riboflavin. Highly sensitive and selective electrochemical voltammetric detection is realized based on the synergistic effect of electrodeposited reduced graphene oxide (rGO) and platinum nanoparticles (PtNPs) with a low detection limit of 1.2 nM. The fully integrated system is capable of sweat sampling with the microfluidic patch, real-time riboflavin analysis and pH calibration with the flexible electrode array, as well as wirelessly simultaneous near field communication (NFC) energy harvesting and data transmission with the flexible circuit and a smartphone. On-body human sweat analysis demonstrates high accuracy cross-validated with gold-standard measurements, and reveals a strong correlation between sweat and urine riboflavin levels. The proposed wearable platform opens up attractive possibilities for noninvasive nutrient tracking, providing strong potential for personalized dietary guidance towards precision nutrition. • Battery-free and wireless flexible wearable biosensing system for sweat riboflavin detection. • Real-time sweat sampling, sensing and calibration with microfluidic patch and flexible electrode array. • High sensitivity and selectivity realized by synergistic effect of graphene and platinum nanoparticles. • Positive correlation of sweat and urine riboflavin levels was validated by on-body trials. [ABSTRACT FROM AUTHOR]

This study investigated riboflavin (RF)-mediated Fe0-to-microbe electron transfer corrosion of EH40 steel caused by Halomonas titanicae. The addition of 20 ppm RF to the biotic medium increased the weight loss and maximum pitting depth of EH40 steel by 67 % and 64 %, respectively. After 20 ppm RF injection into a 3-d broth, the biotic corrosion started to increase within minutes, reflecting that the H. titanicae extracellular electron transfer (EET) rate was promoted by RF as an electron mediator. Furthermore, RF increased the expression level of cytochrome c (Cyt c) in sessile cells, which further enhanced the EET capacity of H. titanicae. [Display omitted] • Riboflavin mediates electron transfer biocorrosion of EH40 steel by H. titanicae. • The addition of riboflavin promotes H. titanicae MIC through EET acceleration. • EH40 steel MIC rate starts to increase within minutes after riboflavin injection. • Riboflavin increases the cytochrome c expression of sessile H. titanicae cells. [ABSTRACT FROM AUTHOR]

Matrix-free room temperature phosphorescence (RTP) materials have generated considerable interest in sensing, anti-counterfeiting and bioimaging due to long lifetime and large Stokes shift. However, spin-forbidden transition and non-radiative transition make RTP challenging to implement. In this work, matrix-free RTP carbon dots (CDs) co-doped with boron and nitrogen were prepared through the microwave-assisted strategy. The CDs realize RTP without any protective matrix. This may be attributed to the stable and rigid structure formed during the heating polymerization process, which can protect the triplet excited state from being quenched by oxygen and water in the air environment. The fluorescence and phosphorescence emission wavelength of the as-prepared CDs were observed at 532 nm and 596 nm with the excitation wavelength of 476 nm and 514 nm, respectively, showing a long afterglow lifetime of 735.3 ms. Nitrogen doping has a crucial effect on the luminescence of RTP, and the increase of nitrogen content facilitates the n-π* transition and improve the efficiency of intersystem crossing (ISC). Importantly, the ratiometric fluorescence method for determining riboflavin has been established based on the Förster resonance energy transfer (FRET) between the CDs (Donor) and riboflavin (Acceptor), with a linear relationship in the range of 9.52–85.71 μM and the limit of detection (LOD) of 19.9 nM. Additionally, the phosphorescent property of the CDs was exploited to demonstrate the potential applications in the field of information encryption. [Display omitted] • The CDs exhibited blue fluorescence and green phosphorescence. • The ratiometric fluorescence method for riboflavin was established. • The CDs showed the potentiality of information encryption. • The CDs have a long phosphorescence lifetime of 735.3 ms at 596 nm. • The fluorescence and phosphorescence mechanisms were explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • First study presenting extensive analyses on chemical composition of ushivi. • High proportion of essential amino acids in proteins (manketti 48%, ushivi 45%) • Ushivi beans have high concentrations of vitamins B 1 (thiamine) and B 2 (riboflavin) • Valuable nutritional properties make seeds potential Novel Food candidates. Various species of Southern African plants and their edible seeds have gained huge importance due to positive health aspects, and there is increasing interest to introduce such seeds as Novel Food on the international market. Especially the seeds of Schinziophyton rautanenii (manketti) and Guibourtia coleosperma (ushivi) could have great potential as a food and food ingredient. Hence, extensive analyses on the chemical composition of manketti nuts and ushivi beans including the analysis of total solids, protein and fat content, soluble carbohydrates, ash, total and free amino acids, biogenic amines and polyamines, fatty acid profile as well as the content of certain B-vitamins and tocopherols were performed. Results obtained showed a valuable nutritional composition, e.g., a true protein content of 22.6% with a ratio of essential amino acids to total amino acid composition of 48% in manketti nuts, while ushivi beans had a true protein content of 8.2% with a similar ratio of essential to total amino acids (45%). Lipid content was 54.1% in manketti nuts, ushivi beans had a value of 7.7%. In both, linoleic acid was the most abundant. Furthermore, ushivi beans had high amounts of vitamin B 1 and B 2. [ABSTRACT FROM AUTHOR]

Riboflavins are secreted under iron deficiency as a part of the iron acquisition Strategy I, mainly when the external pH is acidic. In plants growing under Fe-deficiency and alkaline conditions, riboflavins have been reported to accumulate inside the roots, with very low or negligible secretion. However, the fact that riboflavins may undergo hydrolysis under alkaline conditions has been so far disregarded. In this paper, we report the presence of riboflavin derivatives and products of their alkaline hydrolysis (lumichrome, lumiflavin and carboxymethylflavin) in nutrient solutions of Cucumis sativus plants grown under different iron regimes (soluble Fe-EDDHA in the nutrient solution, total absence of iron in the nutrient solution, or two different doses of FeSO 4 supplied as a foliar spray), either cultivated in slightly acidic (pH 6) or alkaline (pH 8.8, 10 mM bicarbonate) nutrient solutions. The results show that root synthesis and exudation of riboflavins is controlled by shoot iron status, and that exuded riboflavins undergo hydrolysis, especially at alkaline pH, with lumichrome being the main product of hydrolysis. • Iron deficient cucumber plants grown in alkaline nutrient solutions secrete riboflavins. • Riboflavins secreted to alkaline nutrient solutions are hydrolyzed mainly into lumichrome. • Riboflavin synthesis and exudation is controlled by shoot iron status. • Bicarbonate does not affect the expression of root riboflavin synthesis genes. [ABSTRACT FROM AUTHOR]

Myricanol (MY) is one of the main active components from bark of Myrica Rubra. It is demonstrated that MY rescues dexamethasone (DEX)-induced muscle dysfunction via activating silent information regulator 1 (SIRT1) and increasing adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation. Since SIRT1 and AMPK are widely involved in the metabolism of nutrients, we speculated that MY may exert beneficial effects on DEX-induced metabolic disorders. This study for the first time applied widely targeted metabolomics to investigate the beneficial effects of MY on glucose, lipids, and protein metabolism in DEX-induced metabolic abnormality in mice. The results showed that MY significantly reversed DEX-induced soleus and gastrocnemius muscle weight loss, muscle fiber damage, and muscle strength loss. MY alleviated DEX-induced metabolic disorders by increasing SIRT1 and glucose transporter type 4 (GLUT4) expressions. Additionally, myricanol prevented muscle cell apoptosis and atrophy by inhibiting caspase 3 cleavages and muscle ring-finger protein-1 (MuRF1) expression. Metabolomics showed that MY treatment reversed the serum content of carnitine ph-C1, palmitoleic acid, PS (16:0_17:0), PC (14:0_20:5), PE (P-18:1_16:1), Cer (t18:2/38:1(2OH)), four amino acids and their metabolites, and 16 glycerolipids in DEX mice. Kyoto encyclopedia of genes and genomes (KEGG) and metabolic set enrichment analysis (MSEA) analysis revealed that MY mainly affected metabolic pathways, glycerolipid metabolism, lipolysis, fat digestion and absorption, lipid and atherosclerosis, and cholesterol metabolism pathways through regulation of metabolites involved in glutathione, butanoate, vitamin B6, glycine, serine and threonine, arachidonic acid, and riboflavin metabolism. Collectively, MY can be used as an attractive therapeutic agent for DEX-induced metabolic abnormalities. [Display omitted] • Metabolomics was used to study the effects of myricanol on metabolic disorders. • Myricanol reversed DEX-induced muscle weight and strength loss, muscle fiber damage. • Myricanol alleviated muscle damage by modulating SIRT1, GLUT4, MuRF1 and Caspase 3. • Myricanol mainly reversed DEX-induced lipid metabolism pathways. • Myricanol reversed glutathione, VB6, Gly-Ser-Thr, arachidonic acid, and riboflavin metabolism. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simulated microgravity increases the current generation of EAB. • Simulated microgravity increases EAB biomass and enriches Geobacter. • Simulated microgravity induces the changes in gene and protein of anodic biofilm. Electrochemically active bacteria (EAB) exhibit promising prospects for space exploration and life support systems. However, the effects of the space environment on EAB are unclear. In this study, the effects of simulated microgravity on the current generation of mixed-culture EAB were illustrated, and the underlying mechanism was elucidated. The results demonstrated that the electrochemical activity of mixed-culture EAB was enhanced, which was mainly due to the enrichment of Geobacter and the increase in EAB biomass. Additionally, the genes and proteins of the biofilm changed obviously under simulated microgravity conditions, including: I) genes related to signal transfer, II) genes related to cell wall synthesis, and III) genes related to riboflavin synthesis. This study first revealed the enrichment in EAB abundance, the increase in EAB biomass, and the promotion of current generation under simulated microgravity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A. faecalis ZS-1 possesses simultaneous bioelectricity generation and CO 2 fixation. • Bioelectricity promotes the formation of electrotrophic bacterial biofilms. • Riboflavin is responsible to inward EET at biocathode during CO 2 -fixing process. • The high expression of ppc gene increases the performance of CO 2 fixation. • Bioelectricity contributes to converting carbon dioxide into lipids in MFC system. The CO 2 fixation mechanism by Alcaligenes faecalis ZS-1 in a biocathode microbial fuel cell (MFC) was investigated. The closed-circuit MFC (CM) exhibited a significantly higher CO 2 fixation rate (10.7%) compared to the open-circuit MFC (OC) (2.0%), indicating that bioelectricity enhances CO 2 capture efficiency. During the inward extracellular electron transfer (EET) process, riboflavin concentration increased in the supernatant while cytochrome levels decreased. Genome sequencing revealed diverse metabolic pathways for CO 2 fixation in strain ZS-1, with potential dominance of rTCA and C4 pathways under electrotrophic conditions as evidenced by significant upregulation of the ppc gene. Differential metabolite analysis using LC-MS demonstrated that CM promoted upregulation of various lipid metabolites. These findings collectively highlight that ZS-1 simultaneously generated electricity and fixed CO 2 and that the ppc associated with bioelectricity played a critical role in CO 2 capture. In conclusion, bioelectricity resulted in a significant enhancement in the efficiency of CO 2 fixation and lipid production. [ABSTRACT FROM AUTHOR]

• Examined the association between community green space exposure and heart health for Chinese older adults. • General heart heat was measured through electrocardiography. • Street view trees (SVG-tree) and grass (SVG-grass) were used as the proxy for green space exposure. • SVG-grass is negatively associated with older adults' odds of reporting electrocardiographic abnormalities. • The effectt of SVG was more pronounced for males, older adults with lower income or educational attainment. Heart health is important for the quality of life, especially for older adults. Awareness is mounting that green space possibly matters for promoting heart health. While most studies mainly focused on the relationship between green space and cardiovascular diseases among older adults, scant attention has been paid to general heart heat measures through electrocardiography (ECG). This study aims to systematically assess the association between community green space exposure and heart health for Chinese older adults using street view and ECG. This observational, cross-sectional study was based on data from the 33 Chinese Community Health Study (33 CCHS). The heart health was measured by the presence of electrocardiographic abnormalities. We used street view data to calculate exposure to community street view green space (SVG) and further distinguished between street view trees (SVG-tree) and grass (SVG-grass). As a green space reference, we also incorporated the Normalized Difference Vegetation Index (NDVI). The results showed that SVG-grass was negatively associated with older adults' odds of reporting electrocardiographic abnormalities, but there is no evidence that SVG-tree or NDVI was related to that. Also, the stratified analyses indicated that the results vary across demographic and socioeconomic groups. Heart health for males and older adults with lower income or educational attainment were significantly associated with SVG exposure, while such findings were not found for their counterparts. Our findings suggest ECG and street view data are promising in understanding green space-heart health associations. Hence, it is essential to promote the provision and visibility of community green space especially for older adults in disadvantaged groups. [ABSTRACT FROM AUTHOR]

Corneal collagen crosslinking (CXL) is a commonly used minimally invasive surgical technique to prevent the progression of corneal ectasias, such as keratoconus. Unfortunately, riboflavin/UV-A light-based CXL procedures have not been successfully applied to all patients, and result in frequent complications, such as corneal haze and endothelial damage. We propose a new method for corneal crosslinking by using a Ruthenium (Ru) based water-soluble photoinitiator and visible light (430 nm). Tris(bipyridine)ruthenium(II) ([R u (bpy) 3 ]2+) and sodium persulfate (SPS) mixture covalently crosslinks free tyrosine, histidine, and lysine groups under visible light (400–450 nm), which prevents UV-A light-induced cytotoxicity in an efficient and time saving collagen crosslinking procedure. In this study, we investigated the effects of the Ru/visible blue light procedure on the viability and toxicity of human corneal epithelium, limbal, and stromal cells. Then bovine corneas crosslinked with ruthenium mixture and visible light were characterized, and their biomechanical properties were compared with the customized riboflavin/UV-A crosslinking approach in the clinics. Crosslinked corneas with a ruthenium-based CXL approach showed significantly higher young's modulus compared to riboflavin/UV-A light-based method applied to corneas. In addition, crosslinked corneas with both methods were characterized to evaluate the hydrodynamic behavior, optical transparency, and enzymatic resistance. In all biomechanical, biochemical, and optical tests used here, corneas that were crosslinked with ruthenium-based approach demonstrated better results than that of corneas crosslinked with riboflavin/ UV-A. This study is promising to be translated into a non-surgical therapy for all ectatic corneal pathologies as a result of mild conditions introduced here with visible light exposure and a nontoxic ruthenium-based photoinitiator to the cornea. Keratoconus, one of the most frequent corneal diseases, could be treated with riboflavin and ultraviolet light-based photo-crosslinking application to the cornea of the patients. Unfortunately, this method has irreversible side effects and cannot be applied to all keratoconus patients. In this study, we exploited the photoactivation behavior of an organoruthenium compound to achieve corneal crosslinking. Ruthenium-based organic complex under visible light demonstrated significantly better biocompatibility and superior biomechanical results than riboflavin and ultraviolet light application. This study promises to translate into a new fast, efficient non-surgical therapy option for all ectatic corneal pathologies. [Display omitted] [ABSTRACT FROM AUTHOR]

Scleral photocrosslinking is increasingly investigated for treatment of myopia and glaucoma. In this study a computational model was developed to predict crosslinking efficiency of visible/near infrared photosensitizers in the sclera. Photocrosslinking was validated against riboflavin corneal crosslinking experimental studies and subsequently modeled for the sensitizer, methylene blue, administered by retrobulbar injection to the posterior sclera and irradiated with a transpupillary light beam. Optimal ranges were determined for treatment parameters including light intensity, methylene blue concentration, injection volume, and inspired oxygen concentration. Additionally, sensitivity of crosslinking to various parameters was quantified. The most sensitive parameters were oxygen concentration in the injection solution, scleral thickness, and injection reservoir thickness (i.e., injection volume). [Display omitted] • Scleral stiffening by photocrosslinking was modeled for glaucoma/myopia treatments. • The model was validated against published riboflavin corneal photocrosslinking data. • Scleral crosslinks and treatment parameters were modeled over space and time. • Optimal ranges for treatment parameters for photocrosslinking were predicted. • Sensitivity analysis suggests tissue parameters were most impactful to crosslinking. [ABSTRACT FROM AUTHOR]

The interactions between non-starch polysaccharides alter the physicochemical properties of the mucin, therefore can affect encapsulated nutrients penetrating through the mucus layer in the gastrointestinal tract. This study explored the interactions between mucin and galactomannans (GMs) with different mannose-to-galactose ratios going through contact, diffusion, and binding stages. During contact stage, the contact angle was used to characterize the interactions between mucin and GMs, and results showed that locust bean gum (4:1) with lower molecular weight had more contact area to form more hydrogen bonds with water. At diffusion and binding stage, based on the analysis of ATR-FTIR, rheology, and fluorescence spectroscopy, more galactose side chains in guar gum (2:1) had more hydrogen donors and acceptors and more space between polysaccharides to form intermolecular hydrogen bonds with mucin, which enhanced the interactions with mucin. Molecular docking results suggested that more hydrogen bonds in the main chain and less in the side chain resulted in more availability to form intramolecular hydrogen bonds and therefore reduced the strength of the interactions with mucin. Moreover, the Transwell assay revealed that enhancing the interactions of GMs with mucin, especially hydrogen bonds, slowed down the migration of the riboflavin. The current discovery laid the groundwork for designing GMs-based delivery systems that are capable to control the duration of nutrient action on the mucus by changing the molecular properties of the polysaccharide. [Display omitted] • Three-stage interaction mechanism between mucin and GMs was discussed. • Mannose-to-galactose ratios of GMs regulate the interactions with mucin. • Interaction mechanism can control the migration behavior of riboflavin. [ABSTRACT FROM AUTHOR]

Herein, we report for the first time the incorporation of riboflavin as a bioactive additive in soy protein isolate films, along with investigating the impact of UV light treatment, thereby creating functional packaging material. Our investigation involves a comprehensive characterization of the films, including morphological, physicochemical, and mechanical properties, as well as their effectiveness as light barriers, antimicrobial potential, and biodegradation properties. The UV treatment of riboflavin/soy protein dispersions leads to the formation of films exhibiting minor water swelling and total soluble matter compared to those untreated with UV light, suggesting the development of a cross-linked network. Moreover, increased riboflavin content enhances the cross-linked network's robustness. The mechanical properties of the films exhibit a notable improvement with UV treatment and with increasing riboflavin content until a limit value, showcasing increased tensile strength and Young's modulus. Films showed homogeneous surfaces with an absence of pores and cracks and the ability to act as a barrier for oil passage. Films were assayed as a coating material for chia oil samples exposed to high-intensity UV light, showing great protection capacity. It has been demonstrated that an increase in riboflavin concentration enhances the UV light-blocking properties, making these films promising candidates for storing light-sensitive food products while preserving their nutritional quality. In addition, antibacterial action against S. aureus was determined by disk diffusion assay. Furthermore, the films exhibited relatively short disintegration times under soil burial conditions, even after chemical modification. This research contributes valuable insights to the innovative field of sustainable food packaging materials. [Display omitted] • UV treatment and riboflavin incorporation lead to improved mechanical properties. • Films exhibiting superior water resistance compared to those untreated with UV light. • Increasing riboflavin proportion enhances UV light-blocking properties of the films. • Films exhibited relatively short biodegradation times under soil burial conditions. • The prepared films are promising candidates for storing light-sensitive food products. [ABSTRACT FROM AUTHOR]

Fatty acid (FA), carotenoid and vitamin contents of UK eggs were assessed for four production systems (caged (CA), free-range (FR), organic (OR) and extensive organic (EO)) as well as season. The impact of enforced housing, due to avian influenza, was also investigated. Production system did not alter vitamin D 3 , B 2 or B 9 content, but significantly influenced nutritionally desirable FA, carotenoid and vitamins A and E - concentrations decreased as production intensity increased, although for most, CA and FR did not differ significantly. Vitamin E and FA profiles for OR and EO were also similar, although carotenoids were higher in EO eggs. In contrast, FA, carotenoids, vitamins E and B 9 were consistent throughout the year, unlike vitamins A, D 3 and B 2 , which fluctuated with season; D and B 2 were higher in July than January and lower vitamin A was the only detected implication from enforced housing of FR and OR birds. • Fatty acid, carotenoid and vitamins in eggs from caged, free range and organic hens • Eggs from free range and caged systems were very similar • Nutrients in organic eggs were higher than free range and cage eggs • Vitamins A, E, B 9 , carotenoids and fatty acids were consistent throughout the year • Vitamin D and B 2 were higher in summer than winter [ABSTRACT FROM AUTHOR]

Nanomaterial-based sensors are transforming chemical detection, merging nanotechnology's precision with sensor versatility amid growing chemical health concerns. In our study, we synthesized copper oxide (CuO) nanostructures at various pH levels using a low-temperature hydrothermal process and characterized them in detail. We utilized these CuO nanostructures to develop a chemical sensor for detecting ethanol in gas form and riboflavin in liquid solutions. Remarkably, the sensor utilizing CuO nanostructures synthesized at pH 9 exhibited superior sensing performance for ethanol concentrations ranging from 10 to 100 ppm, with an outstanding response of 132% at 100 ppm ethanol and an operating temperature of 250 °C, and a detection limit at 10 ppm with a response of 36%. For riboflavin detection, the CuO nanostructure-based riboflavin sensor demonstrated high sensitivity (183 µA/µM cm²) within a 50–800 nM concentration range. Our study highlights not only the superior performance, reproducibility, stability, selectivity, and application in real samples of these sensors but also their potential for broader applications by integrating enzymes, antibodies, or other modifications. [Display omitted] • CuO nanostructures at various pH levels were obtained using a hydrothermal process. • Developed a chemical sensor using CuO nanostructures to detect ethanol in gas form and riboflavin in liquid solutions. • CuO nanostructures synthesized at pH 9 exhibited superior sensing performance for ethanol. • CuO nanostructure-based riboflavin sensor demonstrated high sensitivity (183 µA/µM/cm²) in a 50-800 nM concentration range. • The sensor's reproducibility, stability, selectivity, and real sample performance were rigorously evaluated. [ABSTRACT FROM AUTHOR]

Differently colored foxtail millet (Setaria italica) cultivars were compared regarding their amylose, B-complex vitamin, vitamin E, and phenolic compositions, as well as the bioaccessibility of their phenolics in simulated in vitro digestion. Dark-colored foxtail millets contained more thiamine, pyridoxine, and tocopherols, but less riboflavin, than light-colored ones. Phenolics were more abundant in dark-colored cultivars. Insoluble bound fractions accounted for 75%–83% of the total phenolics, with ferulic acid detected as the most plentiful compound. The major bioaccessible phenolic was free ferulic acid, with 100%–120% bioaccessibility, depending on cultivar, followed by p -coumaric acid and isoferulic acid (50%–80%). These relatively high bioaccessibilities were likely due to the release of soluble conjugated or insoluble bound phenolics during digestion. However, the contents of other free phenolics were largely decreased following in vitro digestion, resulting in low bioaccessibility, which also means that the release from the conjugated and bound fractions was poor. • Improved phytochemical profiling of compounds in foxtail millet. • Dark-colored millets contain higher levels of conjugated and bound phenolics. • First report of conjugated and bound phenolics' bioaccessibility in foxtail millet. • Free ferulic acid was the major bioaccessible phenolics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluoroquinolones (FQ) may be degraded by different ROS. • Ionization state and fluorine atoms in FQ regulate their ROS-mediated degradation. • ROS-mediated degradation products of FQ were nontoxic in Vero cells. • Fluorine atoms increase FQ electron donor ability by fluoromaticity effect. Fluoroquinolones have been attractive broad-spectrum antibiotics for ophthalmic application. However, they have shown phototoxicity as a significant side effect, which is strongly dependent on fluoroquinolone structure and some environment conditions. Beyond their photo-reactivity, an indirect light-induced process deserves to be considered. The photosensitized action of molecules present in the ocular organ, such as Riboflavin, may produce reactive oxygen species (ROS) that could degrade fluoroquinolones. As a consequence, the antibiotics may lose their therapeutic action and/or produce degradation products with harmful effects on health. In this contribution, a kinetic analysis of ROS-mediated degradation processes of ophthalmic quinolones is addressed. Further, considering the evidence towards the structure-modulated phototoxicity, we evaluated the influence of structural fluorine atoms on these processes. The non-fluorinated precursor Nalidixic Acid and the fluoroquinolones (Ciprofloxacin, Norfloxacin and Lomefloxacin) were selected for this study. Cytotoxicity experiments in Vero cells were performed in order to investigate the potential toxicity of the ROS-mediated degradation products. Our results suggest that quinolones may be degraded by ROS and these processes are regulated by the ionization state of quinolone and the presence of fluorine atoms in their structure. Both effects increase the electron donor ability of the quinolones, which favor electron transfer processes and increase their reactivity towards species with an electrophilic character. Interestingly, this fluorine-dominated effect has been recently called "fluoromaticity". Cytotoxicity assays indicated that neither the Qs nor their ROS-mediated degradation products presented injury on Vero cells under the current experimental conditions. [ABSTRACT FROM AUTHOR]

The objective of this study was to improve the rheological properties and riboflavin delivery ability of soy protein isolate (SPI) gels by incorporating sodium carboxymethyl cellulose (CMC) through glycosylation. The investigation focused on the structural and gel properties of SPI–CMC conjugates at different Maillard reaction times (30, 60, 90, 120, and 150 min). The results showed that the degree of grafting initially increased and then decreased as the Maillard reaction times increased, reaching its peak at 90 min (25.52%). The changes in the structure and conformation of the SPI–CMC conjugates were verified by Fourier transform infrared spectroscopy and surface hydrophobicity. An appropriate Maillard reaction reduced the content of highly ordered α-helix and β-sheet while increasing the content of disordered random coil and β-turn. This secondary structural change led to protein unfolding, exposure of surface hydrophobic groups, and orderly aggregation, forming a dense cross-linked gel network. When the Maillard reaction times increased, especially for 90 min, the gel strength and water-holding capacity of the SPI–CMC conjugate gels were significantly increased, along with a denser microstructure. Compared with the SPI and SPI–CMC mixture, SPI–CMC conjugate gels with 60 and 90 min reaction times exhibited notably increased viscosity and storage modulus (G′), as well as better structural recovery characteristics. The above physicochemical property improvements markedly enhanced the riboflavin encapsulation efficiency and riboflavin delivery ability of SPI–CMC conjugate gels, improving the ability to protect riboflavin from photodegradation and slowly releasing riboflavin in the simulated intestinal environment. Hence, SPI–CMC conjugate gels have significant potential for the delivery of nutrients. [Display omitted] • Soy protein isolate was covalently linked with sodium carboxymethyl cellulose to form conjugates through Maillard reaction. • Glycation altered secondary structure and exposed hydrophobic groups of conjugates. • Appropriate glycation improved the rheological properties and gel strength of conjugates gels. • Appropriate glycation improved protection and delivery of conjugates gels for riboflavin. [ABSTRACT FROM AUTHOR]

Guanosine 5′-triphosphate (GTP) provides precursors for the biological synthesis of various valuable compounds. However, the insufficient supply of GTP is often encountered when engineering microbes for the synthesis of certain products, which results in metabolic imbalance and unsatisfying product yield. To tackle this issue, a general strategy for improving GTP regeneration was developed in this study. The effects of dosage and combination strategy of genes related to GTP synthesis were examined to pinpoint the most critical genes influencing GTP production in Escherichia coli. A regeneration system of GTP was derived by the overexpression of genes guaA and guaB , the intracellular GTP concentration of which improved by 81%. To further verify the applicability of the engineered GTP regeneration system on strengthening the product synthesis, it was applied to the production of riboflavin and colanic acid that required GTP as a precursor. It turned out that the titer of riboflavin was increased by 95.8% and the titer of colanic acid was increased by 44%. The GTP regeneration system developed here can also be applied to other products that use GTP as a precursor or require GTP as a cofactor. [Display omitted] • The effect of dosage of individual genes of the GTP synthesis pathway on GTP synthesis was evaluated. • A generalized GTP regeneration system has been constructed. • The GTP regeneration systems was verified in promoting riboflavin and colanic acid production. [ABSTRACT FROM AUTHOR]