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Fungal infections caused by Candida species pose a serious threat to humankind. Antibiotics abuse and the ability of Candida species to form biofilm have escalated the emergence of drug resistance in clinical settings and hence, rendered it more difficult to treat Candida -related diseases. Lethal effects of Candida infection are often due to inefficacy of antimicrobial treatments and failure of host immune response to clear infections. Previous studies have shown that a combination of riboflavin with UVA (riboflavin/UVA) light demonstrate candidacidal activity albeit its mechanism of actions remain elusive. Thus, this study sought to investigate antifungal and antibiofilm properties by combining riboflavin with UVA against Candida albicans and non- albicans Candida species. The MIC 20 for the fluconazole and riboflavin/UVA against the Candida species tested was within the range of 0.125–2 μg/mL while the SMIC 50 was 32 μg/mL. Present findings indicate that the inhibitory activities exerted by riboflavin/UVA towards planktonic cells are slightly less effective as compared to controls. However, the efficacy of the combination towards Candida species biofilms showed otherwise. Inhibitory effects exerted by riboflavin/UVA towards most of the tested Candida species biofilms points towards a variation in mode of action that could make it an ideal alternative therapeutic for biofilm-related infections. • UVA photoactivated riboflavin generates reactive oxygen species (ROS). • Riboflavin/UVA exhibits inhibitory activity on planktonic Candida species. • Riboflavin/UVA demonstrates antibiofilm activity against biofilms of Candida species. • UVA combination with riboflavin serves as an ideal complementary therapeutic for biofilm-related infections. [ABSTRACT FROM AUTHOR]

[Display omitted] • RF can bind to TβR1 and block TGF-β1 signaling activation in pancreatic cancer cells. • RF inhibits metastasis of pancreatic cancer cells both in vitro and in vivo. • Targeting TβR1 to block TGF-β1 signaling explains anti-metastatic effect of RF. • Inhibition of EMT is downstream mechanism of anti-metastatic effect for RF. • The present study provides proof for developing RF as a new anti-metastatic agent. The inhibition of transforming growth factor-β1 (TGF-β1) signaling by targeting TGF-β receptor 1 (TβR1) has been considered as an ideal approach for the prevention of pancreatic cancer metastasis. Utilizing a pharmacophore model for TβR1 inhibitors, candidate compounds with the potential TβR1 binding ability were screened from the U.S. Food and Drug Administration (FDA) database, and riboflavin (RF) with a highest fit value was chosen to investigate its binding ability to TβR1 and effect on TGF-β1 signaling in pancreatic cancer cells. Molecular docking and cellular thermal shift assay (CETSA) proved that RF at pharmacological concentrations could directly bind to TβR1. Further studies showed that pharmacological concentrations of RF in vitro could block TGF-β1 signaling, suppress the migration and invasion, and prevent epithelial-mesenchymal transition (EMT) process of pancreatic cancer cells in the absence or presence of TGF-β1 stimulation, indicating that RF presented anti-metastatic effect in pancreatic cancer cells. Knockdown of TβR1 could significantly attenuate the effects of RF on the migration and EMT process in pancreatic cancer cells, further confirming that the anti-metastatic effect of RF was achieved by blocking TGF-β1 signaling after binding to TβR1. Moreover, in a mouse model of pancreatic cancer metastasis, it was certified that RF administration could block lung and liver metastases, TGF-β1 signaling and EMT process of pancreatic cancer in vivo. In summary, our findings showed that RF could block TGF-β1 signaling by directly binding to TβR1, thereby suppressing the metastasis of pancreatic cancer cells by inhibiting EMT process both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel electroactive 3D-KSC/COF TFPB-Thi was prepared for electrochemical sensing riboflavin. • COF TFPB-Thi was vertically grown on 3D-KSC, which improved stability and use efficiency of COF TFPB-Thi. • Both 3D-KSC and COF TFPB-Thi can catalyze the reduction of riboflavin. • A double signal ratiometric electrochemical riboflavin sensor was prepared based on 3D-KSC/COF TFPB-Thi. • The ratiometric electrochemical riboflavin sensor exhibited better performances for sensing riboflavin. Riboflavin (RF) is one of the necessary vitamins. If human body lacks RF, it will lead to inflammation and dysfunction of mouth, lips and skin. Thus sensitive and accurate determination of RF is necessary. Here, an electroactive covalent-organic framework nanobelt (COF TFPB-Thi) with thickness of 1.4 nm was prepared by amine-aldehyde condensation reaction between thionine and 1, 3, 5-tris (p-formylphenyl) benzene, which was then grown vertically on three-dimensional porous carbon derived from kenaf stem (3D-KSC) for double signal ratiometric electrochemical detection of RF. The resulted 3D-KSC/COF TFPB-Thi showed two reduction peaks at −0.08 V and −0.23 V, which came from the reduction of COF TFPB-Thi and the conjugated structure of COF TFPB-Thi , respectively. In the presence of RF, those RF molecules near the electrode surface were oxidized at 0.6 V. Then some oxidized RF (RF ox) adsorbed on COF TFPB-Thi would oxidize COF TFPB-Thi into COF TFPB-Thi (ox) while other RF ox adsorbed on 3D-KSC kept unchanged. When the potential was scanned from 0.6 V to −0.6 V, both COF TFPB-Thi (ox) and RF ox adsorbed on 3D-KSC were reduced at −0.08 V and −0.45 V accordingly, while the reduction peak of −0.23 V of the conjugated structure of COF TFPB-Thi kept constant. When j -0.45 /j -0.23 was used as the response signal, the detection limit was 44 nM and the linear range was 0.13 μM −0.23 mM. By using j -0.08 /j -0.23 as the response signal, a detection limit of 90 nM and a linear range of 0.30 μM-0.23 mM (S/N = 3) were obtained. By using double signals, the measurement results can be corrected to make the results more accurate and reliable. The sensor also showed good selectivity, reproducibility and stability, which provided a good application prospects. [ABSTRACT FROM AUTHOR]

Photosensitization was developed as a risk-reduction strategy against the contamination by environmental mold spores during the bread cooling phase. Two food-grade photosensitizers -chlorophyllin (CHL) and riboflavin (RBF), were used to evaluate the effect of visible (blue) LED illumination against three common bread spoilage molds. Aided by CHL, 405 nm LEDs inactivated Rhizopus stolonifer and Penicillium expansum by 77.4 ± 3.3% and 52.1 ± 7.3% respectively in 30 min on dichloran rose bengal chloramphenicol agar. These reductions were much higher than the corresponding reductions observed with food-grade RBF and 445 nm LEDs - 22.8 ± 3.2% and 45.5 ± 5.9%, indicating that CHL-based photosensitization was more effective as an intervention than RBF-based photosensitization. When the three molds were illuminated on bread after spraying CHL and spot-inoculation, their populations were reduced by 51–58%. CHL-based photosensitization was observed to retain the texture and moisture of the bread samples, but had a statistically significant impact on their colour. The results of this study suggest that CHL-based photosensitization can be developed as a risk reduction method to prevent the spoilage of bread. • Photosensitization was performed with and without exogenous photosensitizers. • The uptake of photosensitizers by the mold spores ranged from 11 to 25%. • On DRBC agar, 405 nm LEDs and chlorophyllin reduced R. stolonifer by 77.4%. • On bread, this combination was able to kill P. expansum , R. stolonifer and A. niger. • The bread's texture and moisture content were unaffected by the illumination. [ABSTRACT FROM AUTHOR]

Riboflavin is an essential nutrient for humans and animals, and its derivatives flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are cofactors in the cells. Therefore, riboflavin and its derivatives are widely used in the food, pharmaceutical, nutraceutical and cosmetic industries. Advances in biotechnology have led to a complete shift in the commercial production of riboflavin from chemical synthesis to microbial fermentation. In this review, we provide a comprehensive review of biotechnologies that enhance riboflavin production in microorganisms, as well as representative examples. Firstly, the synthesis pathways and metabolic regulatory processes of riboflavin in microorganisms; and the current strategies and methods of metabolic engineering for riboflavin production are systematically summarized and compared. Secondly, the using of systematic metabolic engineering strategies to enhance riboflavin production is discussed, including laboratory evolution, histological analysis and high-throughput screening. Finally, the challenges for efficient microbial production of riboflavin and the strategies to overcome these challenges are prospected. • The application of metabolic engineering and systems biology strategies in microbial production of riboflavin was described. • The challenges and Strategies of microbial effective production of riboflavin were discussed. • Synthetic biology technology will be the driving force for the construction of high-efficiency riboflavin producing strains. [ABSTRACT FROM AUTHOR]

Cow dung generates globally due to increased beef and milk consumption, but its treatment efficiency remains low. Previous studies have shown that riboflavin-loaded conductive materials can improve anaerobic digestion through enhance direct interspecies electron transfer (DIET). However, its effect on the practical anaerobic digestion of cow dung remained unclear. In this study, carbon cloth loaded with riboflavin (carbon cloth-riboflavin) was added into an anaerobic digester treating cow dung. The carbon cloth-riboflavin reactor showed a better performance than other two reactors. The metagenomic analysis revealed that Methanothrix on the surface of the carbon cloth predominantly utilized the CO 2 reduction for methane production, further enhanced after riboflavin addition, while Methanothrix in bulk sludge were using the acetate decarboxylation pathway. Furthermore, the carbon cloth-riboflavin enriched various major methanogenic pathways and activated a large number of enzymes associated with DIET. Riboflavin's presence altered the microbial communities and the abundance of functional genes relate to DIET, ultimately leading to a better performance of anaerobic digestion for cow dung. [Display omitted] • Anerobic digestion of cow dung significantly improved by carbon cloth-riboflavin. • Metagenomics reveal the enhanced mechanism by carbon cloth-riboflavin. • Carbon cloth-riboflavin activated enzymes associated with methane metabolism. • Genes coding for DIET metabolism were of high abundances on carbon cloth. • Riboflavin stimulated DIET by increasing the gene expression of fpoD and hdrA. [ABSTRACT FROM AUTHOR]

Vitamin B 2 plays vital roles in maintaining human health. It is of tremendous significance to construct sensitive sensors of VB 2. In this review, we first briefly presented the sensing mechanisms of fluorescent nanomaterials for sensing VB 2. Subsequently, the advances of nanomaterials for fluorescent determination of VB 2 were highlighted. And sensing performance of traditional approaches and fluorescent nanosensors was further compared. In last section, the challenges and perspectives concerning the topic were discussed. In this review, advances of various fluorescent nanomaterials for fluorescent sensing vitamin B 2 are highlighted. [Display omitted] • Sensing mechanisms of fluorescent nanomaterials for sensing VB 2 were provided. • Comprehensive advances of fluorescent nanomaterials for detection of VB 2 were highlighted. • Performance of VB 2 assay between fluorescent nanosensors and traditional methods was compared. • Challenges and perspectives concerning fluorescent nanosensors for sensing VB 2 were discussed. [ABSTRACT FROM AUTHOR]

Dairy products play a role in the Sustainable Development Goals being a source of high-quality protein (Goal 2) and a profitable branch of economy (Goal 8). The aim of the study was to analyse the content of calcium (Ca), magnesium (Mg), potassium (K), sodium (Na) and riboflavin (vitamin B 2) in 65 yogurts, yogurts to drink, kefirs, buttermilks and homogenized cheese of different flavours. In general, all analysed products had significant content of Ca (43–137 mg 100 g−1) and vitamin B 2 (0.09–0.23 mg 100 g−1), moderate of K (79–173 mg 100 g−1) and low of Mg (6–11 mg 100 g−1). Four products could be labelled with nutrition claim of 'source of calcium' and two with 'source of vitamin B 2 '. At the same time, none of analysed products delivered more than 150 kcal and 70 mg of Na in 100 g and all were available for less than 0.50 EUR per 100 g. Flavoured dairy products, as nutritious alternative to unhealthy snacks, can be considered as a part of a sustainable diet being affordable and culturally acceptable. ● Ca, Mg, K, Na and vitamin B 2 were determined in 65 flavoured dairy products. ● They are a good source of Ca (43–147 mg 100 g−1) and vitamin B 2 (0.09–0.23 mg). ● They have a moderate content of K (79–173 mg) and low of Mg (6–11 mg). ● Flavoured dairy products are low in calories and Na. [ABSTRACT FROM AUTHOR]

White-light-emitting self-healing hydrogels were prepared. The hydrogels can heal the damaged part under a wide range of pH and the emission colors are easily adjustable. White-light-emitting soft materials with self-healing properties show extensive applications in many fields. Herein, a novel self-healing hydrogel is successfully fabricated using oxidized dextran (Odex) and dithiodipropionate dihydrazide (TPH). Carbon dots (CDs), Riboflavin (Ri) and Rhodamine B (RhB) are incorporated into the gel matrix to produce white light emission through fluorescence resonance energy transfer (FRET) process, thus achieving excellent Commission Internationale de L'eclairage (CIE) coordinate value of (0.30, 0.33). The emission colors can be easily tuned via changing proportions of three emitters or the excitation wavelength. When the hydrogels are coated on an ultraviolet light-emitting diodes (UV LED), the hydrogel coating converts UV light to white light and repairs itself in 20 h while a hole is dug from it. Thanks to reversible exchanging reactions of acylhydrazone and disulfide bonds in hydrogel networks, the hydrogel coating exhibits perfect self-healing property in a wide range of pH (from 5 to 9 except for 7). The excellent emission and self-healing properties of hydrogels have great value in practical applications. [ABSTRACT FROM AUTHOR]

Due to their capability of photosynthesis and autotrophic growth, cyanobacteria are currently investigated with regard to the sustainable production of a wide variety of chemicals. So far, however, no attempt has been undertaken to engineer cyanobacteria for the biotechnological production of vitamins, which is probably due to the light-sensitivity of many of these compounds. We now describe a photoautotrophic bioprocess to synthesize riboflavin, a vitamin used as a supplement in the feed and food industry. By overexpressing the riboflavin biosynthesis genes ribDGEABHT from Bacillus subtilis in the marine cyanobacterium Synechococcus sp. PCC 7002 riboflavin levels in the supernatant of the corresponding recombinant strain increased 56-fold compared to the wild-type. Introduction of a second promoter region upstream of the heterologous ribAB gene – coding for rate-limiting enzymatic functions in the riboflavin biosynthesis pathway – led to a further increase of riboflavin levels (211-fold compared to the wild-type). Degradation of the light-sensitive product riboflavin was prevented by culturing the genetically engineered Synechococcus sp. PCC 7002 strains in the presence of dichromatic light generated by red light-emitting diodes (λ = 630 and 700 nm). Synechococcus sp. PCC 7002 naturally is resistant to the toxic riboflavin analog roseoflavin. Expression of the flavin transporter pnuX from Corynebacterium glutamicum in Synechococcus sp. PCC 7002 resulted in roseoflavin-sensitive recombinant strains which in turn could be employed to select roseoflavin-resistant, riboflavin-overproducing strains as a chassis for further improvement. • First bioprocess for photoautotrophic overproduction of riboflavin. • A specialized arrangement of regulatory elements allows overexpression of heterologous riboflavinbiosynthesis genes. • Growth of Synechococcus sp. PCC 7002 under dichromatic red light prevents riboflavin degradation. • A roseoflavin-resistant Synechococcus sp. PCC 7002 strain serves as a chassis for enhanced riboflavin overproduction. [ABSTRACT FROM AUTHOR]

Many metabolic pathways in bacteria are regulated by metabolite sensing riboswitches that exert their control at the level of transcription employing a termination-antitermination mechanism. These riboswitches represent engineering targets to modulate expression of genes and operons relevant for the biotechnological production of commercially relevant compounds. We show that removal of the transcriptional riboswitches that control purine biosynthesis and riboflavin biosynthesis in Bacillus subtilis leads to auxotrophic strains. As an alternative, we report a rational approach for engineering transcriptional riboswitches independently from the availability of structural data. This approach consists in the identification and deletion of a key nucleotide sequence exclusively involved in transcription termination without affecting formation of other secondary and tertiary structures, which can be involved in other functions. To demonstrate the efficacy of our approach, we tested it with regard to deregulation of the purine and the riboflavin biosynthetic pathways in B. subtilis. Following validation of the engineered transcriptional riboswitches using specialized reporter strains, our approach was implemented into a B. subtilis wild-type strain employing CRISPR-Cas9 genome editing. The resulting purine and riboflavin production strains were characterized at the level of gene expression, metabolite synthesis and growth, and a substantial enhancement was measured at each level. Moreover, applying our approach to deregulate the purine pathway of an industrial riboflavin overproducing strain with impaired growth led to an increase in biomass by 53%, which resulted in an enhanced total production of riboflavin in the culture. • Riboswitches represent important regulatory elements in B. subtilis. • We report a new approach to deregulate riboswitches and to enhance gene expression. • Modified riboswitches were introduced into B. subtilis by genome editing. • Performance of resulting strains with regard to production of purines and riboflavin improved. [ABSTRACT FROM AUTHOR]

Intense synthesis of proteins and chemicals in engineered microbes impose metabolic burden, frequently leading to reduced growth and heterogeneous cell population. Thus, the correct balance between growth and production is important. Such balance can be engineered through dynamic control of pathways, but few broadly applicable tools are available to achieve this. We present an autonomous control of gene expression mediated by quorum sensing in Bacillus subtilis , able to self-monitor and induce expression without human supervision. Two variations of the induction module and seven of the response module were engineered generating a range of induction folds and strengths for gene expression control. Our strongest response promoter is 2.5 and 3.2 times stronger than the well-characterized promoters P srfA and P veg , respectively. We applied our strongest autoinduction device for the production of the vitamin B 2. This study presents a toolbox of autoinduction modules for B. subtilis that is modular and tunable. LuxRI quorum sensing based autoinduction device in B. subtilis. Genes luxR and luxI from Aliivibrio fischeri and their respective promoters, called induction module, were inserted as single copy into the genome of B. subtilis. Response modules R1-R7, consisting of one quorum sensing responsive promoter controlling the expression of a gene of interest (or operon of interest), were also inserted as single copy into the genome. The inducer AHL, synthesized by LuxI, diffuses in or out of neighboring cells. When AHL reaches a concentration threshold, it binds to LuxR, which in turn, activates gene expression in the response module. Image 1 • A quorum sensing device was developed for inducer-free gene expression in B. subtilis. • Systematic engineering of the quorum sensing device generated a toolbox for autoinduction of gene expression. • The toolbox contains modules that combined generates an array of induction folds and strengths. • The engineered autoinduction device is modular and tunable. [ABSTRACT FROM AUTHOR]

This investigation profiled circulating serum concentrations of microRNAs (miRNAs) in premature cardiovascular disease (CVD) patients screened for the 677C > T polymorphism in methylenetetrahydrofolate reductase (MTHFR), a risk factor for hypertension. Serum samples from 75 premature CVD patients of known MTHFR genotype were analysed for CVD-related miRNA expression, to identify those that were associated with blood pressure. Samples were collected at baseline and following intervention with riboflavin as part of a randomized controlled trial. In patients with the MTHFR 677TT genotype, expression of miR-199a-5p in serum was inversely correlated with hypertension at baseline, and with change in blood pressure in TT genotype patients who responded to riboflavin intervention. These correlations were not observed in MTHFR 677CC genotype patients. In vitro experiments and in silico data analysis provided evidence that miR-199a-5p targets SMAD4. This is the first study to link miR-199a-5p expression with hypertension in a genetically at-risk cohort of premature CVD patients. • We have successfully profiled miRNA expression in archived serum samples collected from premature CVD patients. • This is the first study to identify miR-199a-5p as a potential serum biomarker of hypertension in a cohort of premature CVD patients. • We suggest miR-199a-5p may play an important role in the pathogenesis of CVD, particularly in at-risk individuals. • Serum profiling of miRNA expression shows potential as a biomarker of blood pressure, which could aid early prediction of CVD risk. [ABSTRACT FROM AUTHOR]

It has been shown that spontaneous release of non-covalent flavins (from flavoenzymes) begins after isolation of mitochondria from rat liver, which is hydrolyzed to riboflavin. This process is stopped by 1 mM EDTA in the incubation medium. In the presence of NADH, deflavinization of flavoproteins leads to formation of superoxide by at least of three processes. The first of these occurs in complex I as a result of the spontaneous release of FMN from the active center. This process is inhibited by adenosine and guanosine phosphates, as well as NAD, but amplified by nicotinamide. The second process is associated with enzymatic hydrolysis of FAD and FMN to riboflavin; it is blocked by EDTA, AMP, NA, NAD. The third process is associated with non-enzymatic hydrolysis of FAD by iron ions in matrix; it is blocked by EDTA and AMP. • Mitochondrial flavins are released from flavoenzymes and subsequent hydrolysed with riboflavin formation after isolation of mitochondria. • The process cleavage of free FAD and FMN occurs by enzymes and non-enzymatically by iron ions. • The resulting free riboflavin interacts with NADH non-enzymatically, producing superoxide (under dark conditions). • This process is blocked by EDTA, AMP and NAD. • The release of FMN is prevented by AMP, GMP, NAD and is accelerated by nicotinamide. [ABSTRACT FROM AUTHOR]

Various food-related stress and intracellular regulators have been previously demonstrated the influence on enterotoxin genes expression, detail information about specific meat nutritional factors promoting enterotoxin genes expression via intracellular regulators still remain unclear. In this study, protein and vitamin B2 as representative nutrients of chicken meat were employed for this preliminary exploration, supplement of protein or vitamin B2 for TSB medium was performed as cultivation in vitro to mimic the contents of protein or vitamin B2 of chicken meat respectively, cell population, virulence regulators and enterotoxin genes expression were determined so as to seek the potential relationship. As a result, there were no significant influences of protein and vitamin B2 on cell growth for four enterotoxigenic Staphylococcus aureus strains, however, various genetic expressing trends were observed within growth cycle, in general, with the comparison of protein and TSB groups, vitamin B2 had universally significant promotion on seb , sec and sed expression, and different strains exhibited varied regulatory preference for enterotoxin genes expression. These results indicated that vitamin B2 is a critical nutritional factor of meat promote enterotoxin genes expression, furthermore, it would provide a new insight into repressing enterotoxin genes expression on the aspect of extracellular nutritional factor. • Supplements of protein and vitamin B2 had negative effects on S. aureus growth. • Vitamin B2 had significant promotion on seb , sec and sed expression. • Different strains had various preference to regulate enterotoxin genes expression. [ABSTRACT FROM AUTHOR]

The rapid resistance of pathogens to antibiotics has emerged as a major threat to global health. Identification of new antibiotic targets is thus needed for developing alternative drugs. Genes encoding enzymes involved in the biosynthesis of riboflavin and flavin cofactors (FMN/FAD) are attractive targets because these enzymatic reactions are necessary for most bacteria to synthesize flavin cofactors for use in their central metabolic reactions. Moreover, humans lack most of these enzymes because we uptake riboflavin from our diet. This review discusses the current knowledge of enzymes involved in bacterial biosynthesis of riboflavin and other flavin cofactors, as well as the functions of the FMN riboswitch. Here, we highlight recent progress in the structural and mechanistic characterization, and inhibition of GTP cyclohydrolase II (GCH II), lumazine synthase (LS), riboflavin synthase (RFS), FAD synthetase (FADS), and FMN riboswitch, which have been identified as plausible antibiotic targets. As the structures and functions of these enzymes and regulatory systems are not completely understood, they are attractive as subjects for future in-depth biochemical and biophysical analysis. [Display omitted] • Current knowledge of enzymes involved in bacterial biosynthesis of riboflavin, FAD, FMN and functions of the FMN riboswitch. • Structural and mechanistic characterization, and inhibition of GTP cyclohydrolase II, lumazine synthase, riboflavin synthase, FAD synthetase, and FMN riboswitch. • The roles of relevant enzymes in the pathways as antibiotic targets. [ABSTRACT FROM AUTHOR]

The commercial and nutritional value of strawberry fruit is drastically reduced due to its susceptibility to decay fungal diseases. In this study, we employed 40 μM riboflavin to delay senescence and decay of strawberry fruit during storage at 4 °C for 12 d. The findings showed that the treatment decreased strawberries mass loss, respiration rate, ROS level, and MDA content and maintained soluble sugars level. Riboflavin treatment maintained high levels of ATP content and energy charge, and activated the activities of succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), H+-ATPase, Ca+-ATPase, glucokinase (GK), fructokinase (FRK), glucose-6-phosphate dehydrogenase (G6PDH), and 6-phosphogluconate dehydrogenase (6-P-GDH) and up-regulated the expression of their encoding genes. In addition, riboflavin-mediated NAD kinase (NADK) activation accelerated the conversion of NAD+ to DADP+ and the accumulation of DADPH. The respiratory pathway switched from the glycolytic (EMP)-tricarboxylic acid cycle (TCA) to the pentose phosphate pathway (PPP), reducing respiratory consumption. As a result, our findings suggest that riboflavin supplementation after harvest maintains a higher level of energy and delays senescence in strawberries. • Riboflavin treatment promoted strawberry respiration rate. • Riboflavin treatment maintained high levels of ATP content and energy charge. • Riboflavin treatment elevated NADPH contents and increased NAD kinase activity. • Enzyme activities involved in energy metabolism were enhanced by riboflavin treatment. [ABSTRACT FROM AUTHOR]

This study explored the impacts of UV-B radiation and cooking methods on the content and release of bioactive components in germinated highland barley. Optimal UV-B radiation (0.2 W m−2 for 6 h/d) increased flavonoid content by the third day, whereas excessive radiation (0.4 W m−2) caused a decrease. Under 0.1 W m−2 UV-B radiation for 9 h/d, polyphenol content rose by 34.40%, and under 0.2 W m−2 for 6 h/d, it increased by 49.40%. After three days of germination under 0.2 W m−2 irradiation for 12 h/d, riboflavin content reached up to 2.5 μg/g. GABA content in the control group increased by 40.21% on the third day compared to the initial, with the highest content in samples irradiated for 3 h/d under 0.2 and 0.4 W m−2. β-glucan content in the control group decreased by 20.15% on the third day compared to the initial, with a more pronounced decrease under long-time high radiation. Different cooking methods affected the release of these components during in vitro digestion. Microwaving proved to be the most effective treatment for promoting the release of flavonoids, polyphenols, riboflavin, and β-glucan, but it was less favorable for GABA release. These findings offer insights for optimizing the nutritional quality of germinated highland barley. • Appropriate UV-B dose boosts bioactive compounds in germinated highland barley. • Excessive UV-B radiation inhibits synthesis of bioactive components. • Heat treatments greatly influence bioactive components in highland germinated barley. • Microwaving enhances the release of flavonoids, polyphenols, and β-glucan. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is riboflavin auxotrophic, but it has two genes envisaged to transform riboflavin into FMN and FAD after its uptaked by specialized transporters. One encodes a bifunctional type I FAD synthase (FADS, herein Lm FADS-1), while the other produces a protein similar to type I at the FMN:ATP adenylyltransferase (FMNAT) site but with a shorter C-terminal that lacks any riboflavin kinase (RFK) motif. This second protein is rare among bacteria and has been named FADS type II (Lm FADS-2). Here we present a biochemical and biophysical study of Lm FADS-1 and Lm FADS-2 by integrating kinetic and thermodynamic data together with sequence and structural prediction methods to evaluate their occurrence in Listeria , as well as their function and molecular properties. Despite Lm FADS-1 similarities to other type I FADSs, (i) its RFK activity has not riboflavin substrate inhibition and occurs under reducing and oxidizing conditions, (ii) its FMNAT activity requires strong reducing environment, and (iii) binding of reaction products, but not substrates, favors binding of the second ligand. Lm FADS-2 produces FAD under oxidizing and reducing environments, but its C-terminus module function remains unknown. Listeria species conserve both FADSs, being sequence identity high within L. monocytogenes strains. Our data exemplify alternative strategies for FMN and FAD biosynthesis and homeostasis, envisaging that in Listeria two FADSs might be required to fulfill the supply of flavin cofactors under niches that can go from saprophytism to virulence. As FADSs are attractive antimicrobial targets, understanding of FADSs traits in different species is essential to help in the discovery of specific antimicrobials. Unlabelled Image • Listeria monocytogenes is riboflavin auxotrophic but has two FAD synthases. • Redox environment and product binding regulate Lm FADS-1 activity to supply FMN. • Lm FADS-1 plus Lm FADS-2 ensure FAD supply from saprophytism to virulence niches. • Potential roles for Lm FADS-2 C-terminal module in flavins homeostasis are evaluated. • FADSs use species specific strategies for FMN and FAD biosynthesis and homeostasis. [ABSTRACT FROM AUTHOR]

Abstract In this study, 14 Turkish Salvia species, 12 of which are endemic, were characterized based on their vitamin B2, mineral, total phenolic contents, and antioxidant activities. Determination of vitamin B2 in Salvia species was achieved by a fast and sensitive capillary electrophoresis technique using a laser induced fluorescence (LIF) detector. All samples contain vitamin B2 ranging from 0.165 to 1.19 mg/100 g. Fifteen elements (Ca, K, Na, Mg, Fe, Mn, Zn, Li, Cu, Co, Al, V, Sr, Sn, and Ni) were determined in each Salvia sample by inductively coupled plasma-mass spectrometry (ICP-MS). Total phenolic contents of the Salvia samples, ranging from 11.8 to 119 mg gallic acid equivalents (GAE)/g, were determined using the Folin-Ciocalteu's method. The antioxidant activities were evaluated by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power assay (FRAP). Analysis data were evaluated by principal component analysis (PCA) and differentiation among Salvia species was shown. Highlights • Fourteen Salvia species were collected from different regions of Turkey. • Vitamin B2 content in Salvia species is firstly reported in this study. • Mineral contents, antioxidant activities, and total phenolics were evaluated. • Principal component analysis was applied to the results to classify the samples. [ABSTRACT FROM AUTHOR]

Abstract Cereal-based functional beverages represent social, economic, and environmental sustainable opportunities to cope with emerging trends in food consumption and global nutrition. Here we report, for the first time, the polyphasic characterization of three cereal-based kefir-like riboflavin-enriched beverages, obtained from oat, maize and barley flours, and their comparison with classical milk-based kefir. The four matrices were successfully fermented with commercial starters: i) milk-kefir and ii) water-kefir, proving the potential of cereal ingredients in the formulation of dairy-like fermented beverages with milk-kefir starter behavior better in these matrices. In the light of their potentiality, seven riboflavin-producing Andean Lactic Acid Bacteria (LAB) were tested for tolerance to food stresses commonly encountered during food fermentation. Moreover, the LAB strains investigated were screened for spontaneous riboflavin overproducing derivatives. Lactobacillus plantarum M5MA1-B2 with outstanding response to stress, was selected to improve riboflavin content in an in situ fortification approach. The combination of L. plantarum M5MA1-B2 riboflavin overproducing strain with milk kefir starter in oat, lead to cover, for one serving of 100 g, 11.4% of Recommended Dietary Allowance (RDA). Besides, addition of L. plantarum M5MA1-B2 improved performance of water kefir in oat and maize matrices. Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) analysis provided the on-line Volatile Organic Compounds profiles supporting the best combination of starter, LAB and cereal matrix for novel functional foods development. Highlights • It is the first study on cereal-based (oat, maize and barley) kefir-like beverages. • Cereal ingredients are suitable matrices for the formulation of dairy-like fermented beverages. • Riboflavin overproducing strains were obtained from Andean LAB of vegetal origin. • L. plantarum M5MA1-B2 plus milk kefir starter rendered the highest riboflavin content in oat. • We underline the relevance of strains of vegetal origin to develop novel cereal-based beverages. [ABSTRACT FROM AUTHOR]

Abstract Resveratrol (RSV) is a small compound first identified as an activator of sirtuin 1 (SIRT1), a key factor in mediating the effects of caloric restriction. Since then, RSV received great attention for its widespread beneficial effects on health and in connection to many diseases. RSV improves the metabolism and the mitochondrial function, and more recently it was shown to restore fatty acid β-oxidation (FAO) capacities in patient fibroblasts harboring mutations with residual enzyme activity. Many of RSV's beneficial effects are mediated by the transcriptional coactivator PGC-1α, a direct target of SIRT1 and a master regulator of the mitochondrial fatty acid oxidation. Despite numerous studies RSV's mechanism of action is still not completely elucidated. Our aim was to investigate the effects of RSV on gene regulation on a wide scale, possibly to detect novel genes whose up-regulation by RSV may be of interest with respect to disease treatment. We performed Next Generation Sequencing of RNA on normal fibroblasts treated with RSV. To investigate whether the effects of RSV are mediated through SIRT1 we expanded the analysis to include SIRT1-knockdown fibroblasts. We identified the aspartoacylase (ASPA) gene, mutated in Canavan disease, to be strongly up-regulated by RSV in several cell lines, including Canavan disease fibroblasts. We further link RSV to the up-regulation of other genes involved in myelination including the glial specific transcription factors POU3F1 , POU3F2 , and myelin basic protein (MBP). We also observe a strong up-regulation by RSV of the riboflavin transporter gene SLC52a1. Mutations in SLC52a1 cause transient multiple acyl-CoA dehydrogenase deficiency (MADD). Our analysis of alternative splicing identified novel metabolically important genes affected by RSV, among which is particularly interesting the α subunit of the stimulatory G protein (Gsα), which regulates the cellular levels of cAMP through adenylyl cyclase. We conclude that in fibroblasts RSV stimulates the PGC-1α and p53 pathways, and up-regulates genes affecting the glucose metabolism, mitochondrial β-oxidation, and mitochondrial biogenesis. We further confirm that RSV might be a relevant treatment in the correction of FAO deficiencies and we suggest that treatment in other metabolic disorders including Canavan disease and MADD might be also beneficial. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study was to measure collagen fiber crimping (CFC) using nonlinear optical imaging of second harmonic generated (SHG) signals to determine the effects of UVA-riboflavin induced corneal collagen crosslinking (UVA CXL) on collagen structure. Two groups, four rabbits each, were treated in the right eye with standard UVA CXL. In vivo confocal microscopy was performed at 1, 2, and 4 weeks after treatment for the first group and up to three months for the second group to measure epithelial/stromal thickness and corneal haze during recovery. Rabbits were sacrificed at one and three months, respectively, and their corneas fixed under pressure. Regions of crosslinking were identified by the presence of collagen autofluorescence (CAF) and then collagen structure was imaged using SHG microscopy. The degree of CFC was determined by measuring the percentage difference between the length of the collagen fiber and the linear distance traveled. CFC was measured in the central anterior and posterior CXL region, the peripheral non-crosslinked region in the same cornea, and the central cornea of the non-crosslinked contralateral eye. No change in corneal thickness was detected after one month, however the stromal thickness surpassed its original baseline thickness at three months by 25.9 μm. Corneal haze peaked at one month and then began to clear. Increased CAF was detected in all CXL corneas, localized to the anterior stroma and extending to 42.4 ± 3.4% and 47.7 ± 7.6% of the corneal thickness at one and three months. There was a significant (P < 0.05) reduction in CFC in the CAF region in all eyes averaging 1.007 ± 0.006 and 1.009 ± 0.005 in one and three month samples compared to 1.017 ± 0.04 and 1.016 ± 0.06 for controls. These results indicate that there is a significant reduction in collagen crimping following UVA CXL of approximately 1%. One possible explanation for this loss of crimping could be shortening of the collagen fibers over the CXL region. Highlights • Corneal thickness remained consistent over time, and corneal haze was shown to peak at one month and then decrease. • CAF showed no decrease between one and three months, indicating persistent mechanical stiffening over time. • Collagen fiber crimping measurements revealed a straighter area of fibers within the crosslinked region, found using CAF. • Cellular staining showed migration of keratocytes into the crosslinked region from the periphery. [ABSTRACT FROM AUTHOR]

Abstract MR1 is a non-classical class I molecule that is highly conserved among mammals. Though discovered in 1995, only recently have MR1 ligands and antigens for MR1-restricted T cells been described. Unlike the traditional class I molecules HLA-A, –B, and –C, little MR1 is on the cell surface. Rather, MR1 resides in discrete intracellular vesicles and the endoplasmic reticulum, and can present non-peptidic small molecules such as those found in the riboflavin biosynthesis pathway. Since mammals do not synthesize riboflavin, MR1 can serve as a sensor of the microbial metabolome and could be key to the early detection of intracellular infection. This review will summarize the current understanding of MR1-dependent antigen presentation. [ABSTRACT FROM AUTHOR]

Abstract The UVA/riboflavin collagen crosslinking (CXL) is one of the treatment procedure for stopping the progression of keratoconus. The inclusion criterion for this procedure is a minimum corneal thickness of 400 μm, which is not often met in patients with advanced keratoconus. Preoperatively swelling thin corneas was shown to stabilize the keratectasia without any postoperative endothelial damage. Recently, we have shown that swelling porcine corneas prior to the CXL treatment had no significant effect on the resulting improvement in their tensile properties. In the present study, we extended this previous study and characterized the stiffening effects of CXL on anterior and posterior flaps as a function of their hydration. A DSAEK system was used to excise 10 mm corneal flaps from 80 porcine corneas. Individual flaps were crosslinked at different initial hydration levels by using riboflavin solutions composed of different dextran concentrations; the thickness was taken as a measure of flap hydration. A DMA machine was used to measure the tensile properties either immediately after the CXL treatment or after the thickness (hydration) of the crosslinked samples was brought down to a specific value. The average thickness of anterior groups was 670 μm, 540 μm, and 410 μm, and the average thickness of posterior groups was 845 μm, 650 μm, and 440 μm. It was found that although CXL significantly increased the tensile properties of all anterior groups, it had an insignificant effect on the stiffness of posterior flaps. Furthermore, except for the posterior flaps in 845 μm and 650 μm thickness groups, decreasing the hydration significantly increased the tensile modulus (p < 0.05). Finally, the anterior flaps that were crosslinked at higher hydration, i.e. swollen before CXL, showed significantly less amount of stiffening in comparison with those crosslinked at lower hydration when the tensile property measurement was done at similar hydration (p < 0.05). Highlights • Characterizing corneal inhomogeneous through-thickness tensile properties. • Measuring the stress-strain response of anterior and posterior flaps under tension. • Determining the interrelation of hydration and collagen crosslinking treatment. [ABSTRACT FROM AUTHOR]

Archaeal/fungal Rib7 and eubacterial RibG possess a reductase domain for ribosyl reduction in the second and third steps, respectively, of riboflavin biosynthesis. These enzymes are specific for an amino and a carbonyl group of the pyrimidine ring, respectively. Here, several crystal structures of Methanosarcina mazei Rib7 are reported at 2.27–1.95 Å resolution, which are the first archaeal dimeric Rib7 structures. Mutational analysis displayed that no detectable activity was observed for the Bacillus subtilis RibG K151A, K151D, and K151E mutants, and the M. mazei Rib7 D33N, D33K, and E156Q variants, while 0.1–0.6% of the activity was detected for the M. mazei Rib7 N9A, S29A, D33A, and D57N variants. Our results suggest that Lys151 in B. subtilis RibG, while Asp33 together with Arg36 in M. mazei Rib7, ensure the specific substrate recognition. Unexpectedly, an endogenous NADPH cofactor is observed in M. mazei Rib7, in which the 2′-phosphate group interacts with Ser88, and Arg91. Replacement of Ser88 with glutamate eliminates the endogenous NADPH binding and switches preference to NADH. The lower melting temperature of ∼10 °C for the S88E and R91A mutants suggests that nature had evolved a tightly bound NADPH to greatly enhance the structural stability of archaeal Rib7. [ABSTRACT FROM AUTHOR]

The abundant sugar and water content make grapes highly susceptible to rot by pathogenic bacteria, which accounts for millions of dollars in revenue loss each year. Herein, to alleviate this problem, rot-proof bronopol embedded-polyurethane hybrid films (PBV) containing 3 g/100 g of Vitamin C (Vc) were developed by electrospinning. PBV films had the lowest water vapor transmission rate when compared to the other groups, with a value of 2.57 mg·cm−2·h−1 (23 °C, 75%), and achieved over 99.99% inhibition of E. coli , S aureus , and B. subtilis. For the PBV films packaged grapes, the content of organic acids increased by more than 10% and the weight loss rate was lowered by over 50%. More importantly, the production rate of CO 2 is 1.64 ppm·g−1·h−1 that can substantially delay grape ripening and spoilage resulting from transpiration. This study offers a facile manufacturing route to develop multifunctional composite films for grape preservation. • PBV film was prepared by electrospinning of TPU and intrinsically antimicrobial PBND.with intrinsic antimicrobial properties was prepared • Mechanical properties of PBV films are qualified for grape packaging. • Antioxidant capacity of PBV films can effectively preserve the nutrients of grapes. • This novel packaging films can reduce the respiration rate of grapes. [ABSTRACT FROM AUTHOR]

After harvest, strawberry fruits are susceptible to mechanical damage and fungal decay, which is extremely detrimental to storage and preservation. Here we performed riboflavin treatment at 20, 40, and 80 μM to delay senescence and reduce microbial growth in strawberry fruits during cold storage for 12 d. The results exhibited that riboflavin treatment inhibited the decay, color deterioration and microbial growth as well as maintained total soluble solid (TSS), titratable acid (TA), ascorbic acid (AsA), firmness and weight. Riboflavin treatment maintained the contents of antioxidant agents during storage period. We also retrieved that riboflavin treatment reduced the activities of polyphenol oxidase (PPO) and peroxidase (POD), whereas improved total phenol content (TPC). The improvement of the antioxidant system caused by enhanced catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities reduced H 2 O 2 content, inhibiting membrane peroxidation in strawberries. In conclusion, riboflavin treatment can effectively extend the shelf-life of strawberries, maintain their morphology and nutritional quality, and delay postharvest senescence. • The riboflavin treatment maintained the strawberry quality. • The riboflavin treatment inhibited PPO and POD activities. • The riboflavin treatment alleviated membrane peroxidation. • The riboflavin treatment enhanced the antioxidant system. [ABSTRACT FROM AUTHOR]

Additional various carbon and free riboflavin could improve anaerobic digestion of waste activated sludge (WAS). However, these substances were not reused. In this study, a reusable riboflavin and carbon black (RCB) co-modified filler was developed and combined with alkaline pretreatment for enhancing the production of volatile fatty acids (VFAs) and methane during anaerobic digestion of WAS. The results showed that RCB-modified fillers exhibited a promoting effect on the reduction of alkali-pretreated WAS. The amounts of the accumulated VFAs mainly containing acetate and the produced methane rose with the increased concentration of immobilized riboflavin (0–0.75 g/L) in the presence of 4 g/L carbon black. When the alkaline pretreatment time of WAS increased from 3 d to 8 d, the amount of methane production increased from 22.8% to 63.9% in the presence of 0.75 g/L riboflavin and 4 g/L carbon black compared with that without RCB-modified fillers. Moreover, 0.75 g/L riboflavin and 4 g/L carbon black had a synergetic effect on promoting methane production via broadening extracellular electron transfer pathways. During this process, microbial dehydrogenase activity, electron transport system activity and coenzyme F420 were enhanced. Microbial community analysis showed that RCB-modified filler addition promoted the enrichment of Syntrophomonas and Pseudomonas involved in direct interspecies electron transfer (DIET). These results indicated that DIET establishment was accelerated. Meanwhile, the populations of acetic acid-producing bacteria including Rikenellaceae_RC9_gut_group and Proteiniphilum , aceticlastic and acid-tolerant methanogenic archaea including Methanosarcina and Methanosaeta , RumEn_M2 were increased. These results indicate that RCB-modified fillers coupled with alkaline pretreatment is an effective method to promote the production of methane during anaerobic digestion of WAS. • A reusable riboflavin and carbon black (RCB) co-modified filler was prepared. • Immobilized riboflavin promoted the production of VFAs and methane. • Carbon black and riboflavin had a synergetic effect on methane production. • RCB-modified filler addition enriched Syntrophomonas and Pseudomonas. • Methanosarcina and RumEn_M2 dominated in RCB-modified filler reactor. [ABSTRACT FROM AUTHOR]

Evolutionary approaches to strain engineering inherently require the identification of suitable selection techniques for the product and phenotype of interest. In this work, we undertake a comparative analysis of two related but functionally distinct methods of high-throughput screening: traditional single cell fluorescence activated cell sorting (single cell FACS) and microdroplet-enabled FACS (droplet FACS) using water/oil/water (w/o/w) emulsions. To do so, we first engineer and evolve the non-conventional yeast Yarrowia lipolytica for high extracellular production of riboflavin (vitamin B2), an innately fluorescent product. Following mutagenesis and adaptive evolution, a direct parity-matched comparison of these two selection strategies was conducted. Both single cell FACS and droplet FACS led to significant increases in total riboflavin titer (32 and 54 fold relative to the parental PO1f strain, respectively). However, single cell FACS favored intracellular riboflavin accumulation (with only 70% of total riboflavin secreted) compared with droplet FACS that favored extracellular product accumulation (with 90% of total riboflavin secreted). We find that for the test case of riboflavin, the extent of secretion and total production were highly correlated. The resulting differences in production modes and levels clearly demonstrate the significant impact that selection approaches can exert on final evolutionary outcomes in strain engineering. Moreover, we note that these results provide a cautionary tale when intracellular read-outs of product concentration (including signals from biosensors) are used as surrogates for total production of potentially secreted products. In this regard, these results demonstrate that extracellular production is best assayed through an encapsulation technique when performing high throughput screening. [ABSTRACT FROM AUTHOR]

The fungus Ashbya gossypii is an important industrial producer of riboflavin, i.e. vitamin B 2 . In order to meet the constantly increasing demands for improved production processes, it appears essential to better understand the underlying metabolic pathways of the vitamin. Here, we used a highly sophisticated set-up of parallel 13 C tracer studies with labeling analysis by GC/MS, LC/MS, 1D, and 2D NMR to resolve carbon fluxes in the overproducing strain A. gossypii B2 during growth and subsequent riboflavin production from vegetable oil as carbon source, yeast extract, and supplemented glycine. The studies provided a detailed picture of the underlying metabolism. Glycine was exclusively used as carbon-two donor of the vitamin’s pyrimidine ring, which is part of its isoalloxazine ring structure, but did not contribute to the carbon-one metabolism due to the proven absence of a functional glycine cleavage system. The pools of serine and glycine were closely connected due to a highly reversible serine hydroxymethyltransferase. Transmembrane formate flux simulations revealed that the one-carbon metabolism displayed a severe bottleneck during initial riboflavin production, which was overcome in later phases of the cultivation by intrinsic formate accumulation. The transiently limiting carbon-one pool was successfully replenished by time-resolved feeding of small amounts of formate and serine, respectively. This increased the intracellular availability of glycine, serine, and formate and resulted in a final riboflavin titer increase of 45%. [ABSTRACT FROM AUTHOR]

In bacteria, biosynthesis of riboflavin occurs through a series of enzymatic steps starting with one molecule of GTP and two molecules of ribulose-5-phosphate. In Bacillus subtilis (B. subtilis) the genes ( ribD/G , ribE , ribA , ribH and ribT ) which are involved in riboflavin biosynthesis are organized in an operon referred as rib operon. All the genes of rib operon are characterized functionally except for ribT . The ribT gene with unknown function is found at the distal terminal of rib operon and annotated as a putative N-acetyltransferase. Here, we report the crystal structure of ribT from B. subtilis (bribT) complexed with coenzyme A (CoA) at 2.1 Å resolution determined by single wavelength anomalous dispersion method. Our structural study reveals that bribT is a member of GCN5-related N-acetyltransferase (GNAT) superfamily and contains all the four conserved structural motifs that have been in other members of GNAT superfamily. The members of GNAT family transfers the acetyl group from acetyl coenzyme A (AcCoA) to a variety of substrates. Moreover, the structural analysis reveals that the residues Glu-67 and Ser-107 are suitably positioned to act as a catalytic base and catalytic acid respectively suggesting that the catalysis by bribT may follow a direct transfer mechanism. Surprisingly, the mutation of a non-conserved amino acid residue Cys-112 to alanine or serine affected the binding of AcCoA to bribT, indicating a possible role of Cys-112 in the catalysis. [ABSTRACT FROM AUTHOR]

A new analytical method that uses high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was developed for the first time for the analysis of vitamins B2 (riboflavin) and B3 (nicotinamide and nicotinic acid) in anchovies. Samples were extracted using four different extraction procedures: acidic hydrolysis (method 1), acidic hydrolysis plus peptide precipitation (method 2), acidic plus enzymatic hydrolysis (method 3) and enzymatic hydrolysis (method 4), and method 1 was found to be very good in terms of recoveries and quantitative results. From an analytical point of view, the separation of three analytes was achieved using a Kinetex Hilic analytical column (100 mm × 4.6 mm i.d.) with isocratic elution in a very short time (2.5 min or chromatography run). The recovery percentages (for method 1) obtained by spiking the matrices at 2.5 and 20 mg kg −1 with a standard mixture of the three analytes were in the range 96.2-105.3%; the correlation coefficients (R 2 ) were always higher than 0.9996, and limits of quantification (LOQs) for all compounds were in the range 1–5 μg kg −1 . Once validated, method 1 was applied to the analysis of 28 anchovy samples, both fresh and canned ones. [ABSTRACT FROM AUTHOR]

The underlying mechanisms responsible for the cardioprotective effects of riboflavin remain elusive. Current study tested the hypothesis that riboflavin protects injured myocardium via epigenetic modification of LSD1. Here we showed that myocardial injury was attenuated and cardiac function was improved in riboflavin-treated mice with experimental myocardial infarction (MI), while these protective effects of riboflavin could be partly blocked by cotreatment with LSD1 inhibitor. Riboflavin also reduced apoptosis in hypoxic (1% oxygen) H9C2 cell lines. Results of ChIP-seq for H9C2 cells showed that riboflavin activated LSD1, as verified by decreased H3K4me2 levels of target genes. Subsequent LEGO bioinformatics analysis indicated that phospholipid metabolism genes Lpcat2 and Pld1 served as the potential target genes responsible for the LSD1 mediated protective effects. Overexpressions of Lpcat2 and Pld1 aggravated hypoxic injury in H9C2 cells, while these detrimental effects could be attenuated by overexpression of LSD1. We thus propose that riboflavin alleviates myocardial hypoxic/ischemic injury by activating LSD1 cellular activity and modulating the expression of phospholipid metabolism genes. LSD1-mediated crosstalk between phospholipid metabolism and histone methylation might thus be an important mechanism for the cardioprotective effects of riboflavin. [ABSTRACT FROM AUTHOR]

Vitamin B2, riboflavin is essential for cellular function, as it participates in a diversity of redox reactions central to human metabolism, through its role as precursor for the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are electron carriers. The electron transfer flavoprotein (ETF) and its dehydrogenase (ETFDH), uses FAD as cofactor. The ETF and ETFDH are forming the electron transport pathway for many mitochondrial flavoprotein dehydrogenases involved in fatty acid, amino acid and choline metabolism. A variation in either ETF or ETFDH causes multiple acyl-CoA dehydrogenation deficiency (MADD), but genetic variations in the riboflavin metabolism or transportation of riboflavin can also cause MADD. The most common variations are located in the riboflavin transporter 2 (RFVT2) and 3 (RFVT3), that are highly expressed in brain and intestinal tissues, respectively. Deficiency of riboflavin transporter 1 (RFVT1), encoded by the SLC52A1 gene, highly expressed in the placenta, has only been reported once. We here report a case of transient MADD, caused by a heterozygous intronic variation, c.1134 + 11G > A, in the SLC52A1 gene encoding RFVT1. This variation creates a binding site for the splice inhibitory hnRNP A1 protein and causes exon 4 skipping. Riboflavin deficiency and maternal malnutrition during pregnancy might have been the determining factor in the outcome of this case. [ABSTRACT FROM AUTHOR]

Biological oxidations form the basis of life on earth by utilizing organic compounds as electron donors to drive the generation of metabolic energy carriers, such as ATP. Oxidative reactions are also important for the biosynthesis of complex compounds, i.e. natural products such as alkaloids that provide vital benefits for organisms in all kingdoms of life. The vitamin B 2 -derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) enable an astonishingly diverse array of oxidative reactions that is based on the versatility of the redox-active isoalloxazine ring. The family of FAD-linked oxidases can be divided into subgroups depending on specific sequence features in an otherwise very similar structural context. The sub-family of berberine bridge enzyme (BBE)-like enzymes has recently attracted a lot of attention due to the challenging chemistry catalyzed by its members and the unique and unusual bi-covalent attachment of the FAD cofactor. This family is the focus of the present review highlighting recent advancements into the structural and functional aspects of members from bacteria, fungi and plants. In view of the unprecedented reaction catalyzed by the family's namesake, BBE from the California poppy, recent studies have provided further insights into nature's treasure chest of oxidative reactions. [ABSTRACT FROM AUTHOR]

Scleral collagen cross-linking is one of the most promising treatments to control the pathologic process of myopia. However, the exact procedure and its impact on animal models of myopia are still to be explored. We modified the scleral riboflavin/ultraviolet A (UVA) cross-linking procedure with an iontophoresis-assisted drug delivery system and an accelerated UVA irradiation (10 mW/cm 2 , 9 min) and applied this treatment to an animal model of myopia. Ninety-six New Zealand White rabbits developed relatively stable myopia by visual deprivation and then underwent the modified scleral cross-linking surgery. All the statistics and sample collection were obtained from 4 postoperative time points (1-day, 10-day, 1-month and 3-month groups). We found that the ultimate stress, Young's modulus and physiological Young's modulus of treated myopia sclera were significantly increased and maintained in 4 groups. The abnormal elongation of the myopic eye was effectively controlled 1 month after the treatment and even almost halted 3 months after the treatment. The histochemical assay revealed no notable post-surgery damage or apoptosis in the retina and choroid. Vigorous collagen synthesis was observed in scleral fibroblasts of the treated samples but were rarely observed in the untreated ones under electron microscopy. Furthermore, the remarkable difference in collagen gene expression and protein content between treated and untreated samples also indicated that an alteration in collagen metabolism may be triggered by the treatment. The effectiveness and safety exploration suggested that the modified scleral cross-linking procedure may be a potential method to control the pathologic process of myopia. [ABSTRACT FROM AUTHOR]

• A novel artificial bacterial consortium was constructed for DON biodegradation. • Paracoccus yeei A9 provides electron for Devosi a sp. A8 to degrade DON. • The DON degradation product was identified as 3-keto-DON. • Several trichothecenes could be degraded by the artificial bacterial consortium. Deoxynivalenol (DON) is a trichothecene mycotoxin mainly produced by various Fusarium species which cause Fusarium head blight in cereals. DON accumulation in grains not only poses a serious health threat to human and animals but also causes economic loss in the food and livestock industries. Here we reported the construction of an artificial bacterial consortium comprising of Devosia sp. A8 and Paracoccus yeei A9 isolated from an enriched bacterial culture, which shows effective degradation capability towards DON. The optimal conditions for temperature, pH and initial inoculum volume for DON degradation were 35 °C, pH 8–9 and 0.5 %, respectively. The degradation product was identified as 3-keto-DON by LC-MS/MS and 1H NMR spectra. Devosia sp. A8 played the major role in DON degradation, but the enhancement of the DON degradation activity by adding NADPH or riboflavin suggested that Paracoccus yeei A9 provided electrons for Devosia sp. A8 to degrade DON. Moreover, other trichothecenes including 15-acetyl DON, 3-acetyl DON and T-2 toxin were also degraded by the consortium. To the best of our knowledge, this is the first report about a Devosia species capable of degrading DON when co-cultured with Paracoccus yeei. The results demonstrated that the artificial bacterial consortium is a potential candidate for DON biodegradation as well as other trichothecene mycotoxins in a safe and eco-friendly manner. [ABSTRACT FROM AUTHOR]

Motivations for seeking local food include eating foods for quality, nutritional value, ethics and environmental concerns. Wild foods, such as wild game and fish, are increasingly included as a local food source, yet many legally procured species of wild game and fish lack knownnutrition information in the USDA National Nutrient Database for Standard Reference (SR). Among those species that lack nutrition information ar e brook trout. The research team worked with the Nutrient Data Laboratory (NDL) within USDA to develop a collection protocol for brook trout. Using legal angling techniques, samples were collected in the Adirondack region of New York State during the months of May and June 2012 by members of the research team. The trout were processed according to USDA determined dissection protocols to attain edible meat portions. Nutrient analysis was conducted on raw brook trout meat samples at USDA appointed commercial laboratories for proximates, calcium, iron, magnesium, phosphorus, potassium, sodium, zinc, riboflavin, niacin, thiamin, Vitamin B6, Vitamin B12, individual fatty acids, and cholesterol. Analytical data was sent to NDL at USDA, where it was reviewed, compiled and published in SR. Nutrient values were determined by validated laboratories using quality assurance procedures. Full nutrient profiles were made available in SR. [ABSTRACT FROM AUTHOR]

There is a lack of information on the various components in germinated soybeans. Therefore, this study aimed to further investigate the differences between three-day -germinated and raw (non-germinated) yellow and black soybeans. The results showed that germination increased the contents of beta-carotene and vitamin B 2 significantly. The free amino acids in raw soybeans were not detected but determined in germinated soybeans, which illustrated that the total free amino acids in germinated soybeans were higher than in raw soybeans. Meanwhile, GABA was 10-fold increased in germinated soybeans. The increase of aglycones of isoflavones was significantly high that reached to over 700% in both soybeans. The total saponin content in germinated yellow soybeans was increased two times whereas there was a slight decline in germinated black soybeans. The anthocyanin content was found to be declined in germinated black soybeans. The current study indicates that three-day- germinated soybeans yield higher nutritional values than raw soybeans, suggesting that the germinated soybeans are a good source of various nutrients and other biologically active compounds. [ABSTRACT FROM AUTHOR]

The rate-limiting step of azo dye decolorization was elucidated by exploring the microbial reduction of a model quinone and the chemical decolorization by previously reduced quinone at different salinity conditions (2–8%). Microbial experiments were performed in batch with a marine consortium. The decolorization of Direct Blue 71 (DB71) by the marine consortium at 2% salinity, mediated with anthraquinone-2,6-disulfonate (AQDS), showed the highest rate of decolorization as compared with those obtained with riboflavin, and two samples of humic acids. Moreover, the incubations at different salinity conditions (0–8%) performed with AQDS showed that the highest rate of decolorization of DB71 by the marine consortium occurred at 2% and 4% salinity. In addition, the highest microbial reduction rate of AQDS occurred in incubations at 0%, 2%, and 4% of salinity. The chemical reduction of DB71 by reduced AQDS occurred in two stages and proceeded faster at 4% and 6% salinity. The results indicate that the rate-limiting step during azo decolorization was the microbial reduction of AQDS. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate corneal enzymatic resistance following epithelium off and on riboflavin/UVA cross-linking (CXL). One hundred and fourteen porcine eyes were divided into four non-irradiated control groups and seven CXL groups. The latter comprised; (i) epithelium-off, 0.1% iso-osmolar riboflavin, 9 mW UVA irradiation for 10 min, (ii) disrupted epithelium, 0.1% hypo-osmolar riboflavin, 9 mW UVA for 10 min, (iii) epithelium-on, 0.25% hypo-osmolar riboflavin with 0.01% benzylalkonium chloride (BACS), 9 mW UVA for 10 min, (iv) epithelium-on, 5 min iontophoresis at 0.1 mA for 5 min with 0.1% riboflavin solution, 9 mW UVA for 10 min or (v) 12.5 min, (vi) epithelium-on, prolonged iontophoresis protocol of 25 min with 1.0 mA for 5 min and 0.5 mA for 5 min with 0.25% riboflavin with 0.01% BACS, 9 mW UVA for 10 min or (vii) 12.5 min. Enzymatic resistance was assessed by daily measurement of a corneal button placed in pepsin solution and measurement of corneal button dry weight after 11 days of digestion. This study revealed that the enzymatic resistance was greater in CXL corneas than non-irradiated corneas (p < 0.0001). Epithelium-off CXL showed the greatest enzymatic resistance (p < 0.0001). The prolonged iontophoresis protocol was found to be superior to all other trans-epithelial protocols (p < 0.0001). A 25% increase in UVA radiance significantly increased corneal enzymatic resistance (p < 0.0001). In conclusion, although epithelium-on CXL appears to be inferior to epithelium-off CXL in terms of enzymatic resistance to pepsin digestion, the outcome of epithelium-on CXL may be significantly improved through the use of higher concentrations of riboflavin solution, a longer duration of iontophoresis and an increase in UVA radiance. [ABSTRACT FROM AUTHOR]

Herein, we present a novel ternary nanocomposite Bi 2 O 3 @MWCNT@g-C 3 N 4 decorated glassy carbon electrode (GCE) for electrochemical detection of Riboflavin (RF). The electrocatalyst Bi 2 O 3 @MWCNT@g-C 3 N 4 was prepared by a simple route; given by ultrasonicated the mixture of Bi 2 O 3 , MWCNT and g-C 3 N 4 in a single pot and then refluxing it to 80 °C. The as-synthesized electrocatalyst showed improved and impressive electrochemical performance due to the synergistic effect of g-C 3 N 4 , MWCNT, and Bi 2 O 3. Additionally, the electrocatalytic response of the prepared Bi 2 O 3 @MWCNT@g-C 3 N 4 /GCE towards RF determination was examined using Cyclic voltammetry (CV) and linear sweep voltammetry (LSV). It has been depicted that in comparison to other prepared materials the Bi 2 O 3 @MWCNT@g-C 3 N 4 /GCE exhibited an impressive electrocatalytic response towards the determination of RF, within a broad linear range (0.02–70 μM) having lower detection limit (1.032 μM). Furthermore, the Bi 2 O 3 @MWCNT@g-C 3 N 4 /GCE also offered improved stability, anti-inference ability, remarkable repeatability and good sensitivity. Finally, the prepared electrocatalyst showed satisfactory results in the real sample analysis of three different pharmaceutical samples containing RF namely Neurobion forte, Supradyn daily and Becosules capsules. [Display omitted] • Bi 2 O 3 @MWCNT@g-C 3 N 4 as a new ternary nanocomposite was synthesized. • Bi 2 O 3 @MWCNT@g-C 3 N 4 modified GCE for Riboflavin electrochemical monitoring. • An impressive linear concentration range and low limit of detection for Riboflavin. [ABSTRACT FROM AUTHOR]

Riboflavin can not only promote cell metabolism, but also prevent cardiovascular diseases. People usually need to obtain riboflavin from food or medicine, so the determination of riboflavin is significant for safety and quality control. An ingenious zinc-based metal-organic framework (Zn-MOF) was synthesized which can be used for rapid fluorescence detection of riboflavin with an ultralow detection limit of 2 ​× ​10−8 ​mol/L. The quenching mechanism is mainly attributed to the fluorescence resonance energy transfer and the absorption competition. In addition, this Zn-MOF can be used as a multifunctional fluorescence probe to specifically recognize acetylacetone and Cr 2 O 7 2−/CrO 4 2−. Most importantly, it has been applied to the quantitative analysis of milk and energy drinks with satisfactory recovery (100.71%–103.42%). It is the first attempt to use MOF as fluorescence probe to determine riboflavin without additional surface modification and functionalization, which provides a promising functional platform for detecting riboflavin in food industry. This Zn-MOF could be used to detect riboflavin with high selectivity and sensitivity in milk and energy drink. [Display omitted] • A novel Zn-MOF was synthesized by hydrothermal method. • The Zn-MOF can be used as a fluorescent probe to detect riboflavin without any additional surface modification and functionalization for the first time. • The proposed method was successfully applied for riboflavin detection in real samples. [ABSTRACT FROM AUTHOR]

To evaluate whether repeated application of riboflavin during corneal cross-linking (CXL) has an impact on the corneal biomechanical strength in ex-vivo porcine corneas. Laboratory investigation. Sixty-six porcine corneas with intact epithelium were divided into three groups and analyzed. All corneas were pre-soaked with an iso-osmolar solution of 0.1% riboflavin in a phosphate-buffered saline (PBS) solution ("riboflavin solution"). Then, the corneas in Groups 1 and 2 were irradiated with a standard epi-off CXL (S-CXL) UV-A irradiation protocol (3 mW/cm2 for 30 min); while the corneas in Group 3 were not irradiated and served as control. During irradiation, Group 1 (CXL-PBS-Ribo) received repeated riboflavin solution application while corneas in Group 2 (CXL-PBS) received only repeated iso-osmolar PBS solution. Immediately after the procedure, 5-mm wide corneal strips were prepared, and elastic modulus was calculated to characterize biomechanical properties. Significant differences in stress-strain extensiometry were found between two cross-linked groups with control group (P = 0.005 and 0.002, respectively). No significant difference was observed in the normalized stiffening effect between Groups 1 and 2 (P = 0.715). The repeated application of riboflavin solution during UV-A irradiation does not affect the corneal biomechanical properties achieved with standard epi-off CXL. Riboflavin application during CXL may be omitted without altering the biomechanical stiffening induced by the procedure. • Riboflavin absorbs UV light and is consumed in the process. • In theory, adding riboflavin during UV irradiation to hydrate the cornea might hinder deeper stromal cross-linking. • We compared the overall corneal strengthening achieved when riboflavin, or PBS was applied during UV-A irradiation. • There was no significant difference in the strengthening effect between the two hydration methods. [ABSTRACT FROM AUTHOR]

The adsorption of acridine orange and Cr6+ ion onto plaster of paris reinforced glutamic acid-grafted-polyacrylamide hydrogel nanocomposite modified with riboflavin, Glu- g -PAM/POP/Rb HNC was studied. The Glu-g-PAM/POP/Rb HNC was physico-chemically characterized by Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, transmission electron microscopy and Brunauer-Emmett-Teller analysis. The specific surface area, pore volume and pore diameter were 15.48 m2/g, 0.015 cm3/g and 4.23 nm, respectively. Adsorption process was strategized by response surface methodology (RSM) based on a 3-level 5-factor (initial solution pH, contact time, adsorbent dose, initial adsorbate concentration and temperature) central composite design (CCD), and validity of the estimated parameters was statistically evaluated using analysis of variance (ANOVA). The optimized operating variables were: pH (AO = 10; Cr6+ = 4.15), contact time (AO = 60 min; Cr6+ = 59 min), adsorbent dose (0.8 g/L), initial adsorbate concentration (60 mg/L) and temperature (298 K). Isotherm results were coincident with Langmuir isotherm model. The experimental kinetic adsorption data was congruous with pseudo-second order model, with the uptake rate controlled by both intraparticle and liquid film diffusions. The relatively high Langmuir saturation capacity of 202.63 mg AO/g and 143.68 mg Cr6+/g, supported by the decent recyclability up to four times affirmed the promising performance of the adsorbent. The efficacy of the adsorbent for simultaneous removal of AO and Cr6+ from bi-component system was assessed. The possible adsorption mechanism mainly involved hydrogen bonding, van der Waals forces, electrostatic and π-π interactions. Adsorption of AO and Cr6+ onto Glu- g -PAM/POP/Rb HNC was feasible and exothermic as revealed by the thermodynamic parameters. The findings demonstrated superior adsorbent efficacy for the seizure of pollutants, particularly AO and Cr6+ from aqueous solution. • Novel Glu-g-PAM/POP/Rb HNC was prepared by graft co-polymerization technique. • Acridine orange and Cr+6 sequestration was optimized using RSM. • Langmuir isotherm model appropriately described the equilibrium data. • Langmuir saturation capacity Q m was 202.63 mg AO/g and 143.68 mg Cr+6/g. • H-bonding, electrostatic, and π-π interactions majorly governed the adsorption. [ABSTRACT FROM AUTHOR]

Riboflavin receptor 3 (RFVT3) is a key protein in energetic metabolism reprogramming and is overexpressed in multiple cancers involved in malignant proliferation, angiogenesis, chemotherapy resistance, and immunosuppression. To enable non-invasive real-time quantification of RFVT3 in tumors, we sought to develop a suitable PET probe that would allow specific and selective RFVT3 imaging in vivo. A novel radiofluorinated riboflavin probe (18F-RFTA) based on riboflavin was synthesized and characterized in terms of radiochemical purity, hydrophilicity, binding affinity, and stability. Positron emission tomography (PET) imaging of 18F-RFTA was performed in U87MG tumor-bearing mice. Immunohistochemistry staining was carried out to determine the expression of RFVT3 in U87MG tumors. 18F-RFTA was characterized by high radiochemical purity and RFVT3 binding affinity, and remarkable stability in vitro and in vivo. Small-animal PET imaging with 18F-RFTA revealed significantly higher uptake in RFVT3-expressing U87MG tumors than in muscle. In conclusion, we have developed the first radiofluorinated riboflavin-based PET probe that is suitable for imaging RFVT3-positive tumors. The new target/probe system can be leveraged for extensive use in the diagnosis and treatment of RFVT3 overexpressing diseases, such as oncologic, cardiovascular, and neurodegenerative diseases. [Display omitted] • A novel PET probe is designed and developed to achieve riboflavin receptor-targeted imaging of glioma mouse models. • The probe exhibited promising pharmacological properties for future translation studies. • The new target/probe system can be leveraged for use in the diagnosis and treatment of riboflavin receptor-related diseases. [ABSTRACT FROM AUTHOR]

ECF transporters are a family of active membrane transporters for essential micronutrients, such as vitamins and trace metals. Found exclusively in archaea and bacteria, these transporters are composed of four subunits: an integral membrane substrate-binding subunit (EcfS), a transmembrane coupling subunit (EcfT), and two ATP-binding cassette ATPases (EcfA and EcfA′). We have characterized the structural basis of substrate binding by the EcfS subunit for riboflavin from Thermotoga maritima , TmRibU. TmRibU binds riboflavin with high affinity, and the protein–substrate complex is exceptionally stable in solution. The crystal structure of riboflavin-bound TmRibU reveals an electronegative binding pocket at the extracellular surface in which the substrate is completely buried. Analysis of the intermolecular contacts indicates that nearly every available substrate hydrogen bond is satisfied. A conserved aromatic residue at the extracellular end of TM5, Tyr130, caps the binding site to generate a substrate-bound, occluded state, and non-conservative mutation of Tyr130 reduces the stability of this conformation. Using a novel fluorescence binding assay, we find that an aromatic residue at this position is essential for high-affinity substrate binding. Comparison with other S subunit structures suggests that TM5 and Loop5-6 contain a dynamic, conserved motif that plays a key role in gating substrate entry and release by S subunits of ECF transporters. [ABSTRACT FROM AUTHOR]