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Methods in Molecular Biology (Clifton,... 2021Riboflavin (vitamin B) is a vitamin of the B group involved in essential biological pathways, including redox reactions and the electron transport chain. Some lactic...
Riboflavin (vitamin B) is a vitamin of the B group involved in essential biological pathways, including redox reactions and the electron transport chain. Some lactic acid bacteria (LAB) can synthesize riboflavin and this capability is strain-dependent. In the last years, a growing interest has focused on the selection of riboflavin-overproducing food-grade LAB for the vitamin biofortification of fermented foods, as well as for the formulation of innovative functional products.In this chapter we report fast and inexpensive techniques in order to (1) screen LAB isolates able to produce riboflavin from different matrices, (2) select spontaneous roseoflavin-resistant riboflavin overproducing strains, and (3) quantify vitamin B in culture media by fluorescence detection.These protocols could be useful to select new overproducing strains and/or species from different ecological niches, as well as to optimize the conditions for vitamin bioproduction.
Topics: Bacteriological Techniques; Culture Media; Drug Resistance, Bacterial; Fermented Foods; Fluorescence; Lactobacillales; Riboflavin
PubMed: 33751425
DOI: 10.1007/978-1-0716-1286-6_1 -
Experimental Eye Research Jun 2022Corneal collagen cross-linking (CXL) is a treatment that is widely applied to halt the progression of ectatic diseases such as keratoconus by creating biomechanical...
Corneal collagen cross-linking (CXL) is a treatment that is widely applied to halt the progression of ectatic diseases such as keratoconus by creating biomechanical strength in the cornea. Most of the studies assessed the effect of the CXL on the cornea without any differentiation of its effect between periphery and the center of the untreated control cornea especially after the 7 days of CXL application. We investigate the ultrastructural changes in the architecture of the center and periphery of rat corneas, 7 days after standard CXL application. Five Wistar rats (10 corneas) were used in the present study. The left eye corneas (5 mm area) were de-epithelialized and irradiated with standard CXL application using riboflavin and Ultraviolet-A (UVA) (3 mW/cm for 30 min). The right eye corneas were used as a control. The sclera-cornea button was removed and processed for electron microscopy. Digital images were captured with a bottom mounted Quemesa camera and analyzed using the iTEM software. The ultrastructure of epithelium, hemi-desmosomes, Bowman's layer and stroma were organized in both untreated control and CXL rat cornea in both untreated control and CXL rat cornea. Within the same CXL cornea, both the collagen fibril (CF) diameter and interfibrillar spacing at the center were significantly smaller compared to the peripheral diameter and spacing of the cornea. When comparing the untreated control and CXL cornea, the central interfibrillar spacing of the CXL cornea was significantly smaller than the central spacing the untreated control cornea. In the CXL cornea the peripheral spacing was significantly higher compared to the peripheral interfibrillar spacing of the untreated control cornea. Within the CXL cornea, the proteoglycans (PGs) area and density of the periphery was significantly higher compared to the area and density of the center of the cornea. It suggests that CXL was more effective at the periphery of the cornea. This could be due to the higher amount of leucine rich PG lumican and higher diffusion of oxygen and riboflavin at the periphery cornea.
Topics: Animals; Collagen; Cornea; Corneal Stroma; Cross-Linking Reagents; Keratoconus; Photosensitizing Agents; Rats; Rats, Wistar; Riboflavin; Ultraviolet Rays
PubMed: 35385757
DOI: 10.1016/j.exer.2022.109064 -
Frontiers in Cellular and Infection... 2022Some spp. are globally emerging opportunistic pathogens that can be dangerous to individuals with underlying medical conditions and for those who are immunocompromised....
Some spp. are globally emerging opportunistic pathogens that can be dangerous to individuals with underlying medical conditions and for those who are immunocompromised. Gram-negative spp. can form resilient sessile biofilms and are found not only in different confined terrestrial settings (e.g., hospitals) but are also frequently detected in spacecraft which is inhabited by astronauts that can have altered immunity. Therefore, spp. pose a serious health hazard in different environments, especially in its biofilm form. Conventional antimicrobials applied to disrupt, inactivate, or prevent biofilm formation have limited efficiency and applicability in different closed-loop systems. Therefore, new, effective, and safe biofilm control technologies are in high demand. The present work aimed to investigate antimicrobial photoinactivation (API) of sp. ESA1 monocultural biofilms mediated by non-toxic, natural photosensitizers such as riboflavin (RF) and chlorophyllin (Chl) with an emphasis of this technology as an example to be safely used in closed-loop systems such as spacecraft. The present study showed that Chl-based API had a bactericidal effect on sp. ESA1 biofilms at twice the lower irradiation doses than was needed when applying RF-based API. Long-term API based on RF and Chl using 450 nm low irradiance plate has also been studied in this work as a more practically applicable API method. The ability of sp. ESA1 biofilms to reduce alamarBlue™ and regrowth analysis have revealed that after the applied photoinactivation, bacteria can enter a viable but non-culturable state with no ability to resuscitate in some cases.
Topics: Humans; Photosensitizing Agents; Biofilms; Anti-Bacterial Agents; Anti-Infective Agents; Riboflavin
PubMed: 36262183
DOI: 10.3389/fcimb.2022.1006723 -
Journal of Cataract and Refractive... Oct 2021Corneal crosslinking (CXL) is the current mainstay treatment for progressive keratoconus. In the past 15 years, a variety of other indications have been tested. A...
Corneal crosslinking (CXL) is the current mainstay treatment for progressive keratoconus. In the past 15 years, a variety of other indications have been tested. A systematic review was conducted to examine these alternative indications for CXL. In total, 143 papers on crosslinking as a treatment for infectious keratitis, bullous keratopathy, pellucid marginal degeneration, and postlaser in situ keratomileusis (LASIK) ectasia and as a way to improve vision either on its own or in combination with other interventions were included. Post-LASIK ectasia is a definite indication for crosslinking. Surprisingly, only limited research has been performed on pellucid marginal degeneration, with no randomized trials available to date. Other interesting applications are the combined use of refractive lasers and crosslinking for suspicious or ectatic corneas and crosslinking as a standalone intervention for minor refractive errors. CXL might offer a solution for refractory bacterial keratitis. In bullous keratopathy, it seems to offer only a transient benefit.
Topics: Collagen; Cornea; Corneal Topography; Cross-Linking Reagents; Humans; Keratoconus; Keratomileusis, Laser In Situ; Photosensitizing Agents; Riboflavin; Ultraviolet Rays
PubMed: 33929804
DOI: 10.1097/j.jcrs.0000000000000663 -
Environmental Science and Pollution... Sep 2020The superoxide anion radical (O) is one of the most predominant reactive oxygen species (ROS), which is also involved in diverse chemical and biological processes. In...
The superoxide anion radical (O) is one of the most predominant reactive oxygen species (ROS), which is also involved in diverse chemical and biological processes. In this study, O was generated by irradiating riboflavin in an O-saturated solution using an ultraviolet lamp (λ = 365 nm) as the light source. The photochemical reduction of 1,4-benzoquinone (p-BQ) by O was explored by 355-nm laser flash photolysis (LFP) and 365-nm UV light steady irradiation. The results showed that the photodecomposition efficiency of p-BQ was influenced by the riboflavin concentration, p-BQ initial concentration, and pH values. The superoxide anion radical originating from riboflavin photolysis served as a reductant to react with p-BQ, forming reduced BQ radicals (BQ) with a second-order rate constant of 1.1 × 10 L mol s. The main product of the photochemical reaction between p-BQ and O was hydroquinone (HQ). The present work suggests that the reaction with O is a potential transformation pathway of 1, 4-benzoquinone in atmospheric aqueous environments.
Topics: Benzoquinones; Oxidation-Reduction; Photolysis; Reactive Oxygen Species; Riboflavin; Superoxides
PubMed: 32488712
DOI: 10.1007/s11356-020-09422-8 -
Photodiagnosis and Photodynamic Therapy Mar 2021To assess the micro-tensile bond strength (μ-TBS), degree of conversion, and antimicrobial capacity of modified dentin adhesive using riboflavin photoinitiators.
PURPOSE
To assess the micro-tensile bond strength (μ-TBS), degree of conversion, and antimicrobial capacity of modified dentin adhesive using riboflavin photoinitiators.
MATERIALS AND METHODS
Three groups of adhesives (control; 0.1 % riboflavin-PDT and 0.5 % riboflavin PDT) were prepared and tested on 70 sound molar teeth. Fourier-transformed infrared spectroscopy (FTIR) was performed for riboflavin and riboflavin-modified adhesives to calculate the degree of conversion. Contact angle measurement was performed by dropping a 5 μL droplet of the adhesives onto polished dentin disk. For μ-TBS testing, the dentin beams were fixed on a micro-tensile tester and were loaded in tension at a cross-head speed of 1 mm per min until fracture. The viability of Streptococcus mutans biofilm was tested using MTT assay.
RESULTS
The spectrum at 1728 cm-1 indicates CO stretching frequency of riboflavin. The groups control and 0.1 % riboflavin PDT showed the highest degree of conversion followed by lowest degree of conversion of 0.5 % riboflavin adhesive after PDT. The control adhesive exhibited the highest contact angle over the dentin surface compared to the riboflavin-modified adhesive groups (p < 0.05). The lowest contact angle was observed for 0.1 % riboflavin that showed increased permeability of the adhesive onto the dentin surface (p < 0.05). The variables of immediate bonding (F = 12.328, p = 0.000) and ageing in artificial saliva (F = 41.559, p = 0.000) significantly affected the bond strength. For aged μ-TBS testing, the scores for 0.1 % riboflavin PDT was significantly higher as compared to the 0.5 % riboflavin PDT samples. The MTT resulted in a lower S. mutans viability for 0.5 % riboflavin PDT compared to 0.1 % riboflavin PDT and control adhesive (p < 0.05), irrespective of any time point, that is, after 24 h and 30 days ageing.
CONCLUSIONS
The addition of riboflavin as photosensitizer in dentin adhesive demonstrated higher bond strength, excellent antimicrobial capability, and degree of conversion following PDT. The addition of riboflavin in dentin adhesive for PDT could be used as a potential restorative material in adhesive dentistry.
Topics: Adhesives; Composite Resins; Dentin; Dentin-Bonding Agents; Materials Testing; Photochemotherapy; Photosensitizing Agents; Resin Cements; Riboflavin
PubMed: 33359161
DOI: 10.1016/j.pdpdt.2020.102145 -
Molecular Microbiology Oct 2022The Lyme disease agent, Borrelia burgdorferi, harbors a significantly reduced genome and relies on the scavenging of critical nutrients from its tick and mammalian hosts...
The Lyme disease agent, Borrelia burgdorferi, harbors a significantly reduced genome and relies on the scavenging of critical nutrients from its tick and mammalian hosts for survival. Riboflavin salvage has been shown to be important for B. burgdorferi infection of mice, yet the contributions of riboflavin to B. burgdorferi metabolism and survival in the tick remain unknown. Using a targeted mass spectrometry approach, we confirmed the importance of bb0318, the putative ATPase component of an ABC-type riboflavin transporter, for riboflavin salvage and the production of FMN and FAD. This analysis further revealed that Δbb0318 B. burgdorferi displayed increased levels of glycerol 3-phosphate compared to the wild-type. The glycerol 3-phosphate dehydrogenase activity of GlpD was found to be FAD-dependent and the transcription and translation of glpD were significantly decreased in Δbb0318 B. burgdorferi. Finally, gene bb0318 was found to be important for maximal spirochete burden in unfed larvae and essential for survival in feeding ticks. Together, these data demonstrate the importance of riboflavin salvage for B. burgdorferi carbon metabolism and survival in ticks.
Topics: Animals; Mice; Adenosine Triphosphatases; Borrelia burgdorferi; Carbon; Flavin Mononucleotide; Flavin-Adenine Dinucleotide; Ixodes; Lyme Disease; Mammals; Oxidoreductases; Riboflavin
PubMed: 36054485
DOI: 10.1111/mmi.14977 -
Biochemistry Feb 2023Flavins are blue-light-absorbing chromophores with rich redox activity. Biologically, the most important are riboflavin (vitamin B), flavin mononucleotide, and flavin...
Flavins are blue-light-absorbing chromophores with rich redox activity. Biologically, the most important are riboflavin (vitamin B), flavin mononucleotide, and flavin adenine dinucleotide, the latter two of which are catalytic cofactors in enzymes. Flavins pivot between oxidized, one electron-, and two electron-reduced forms in different protonation states, depending on enzymatic requirements. Some flavoenzymes use light as a reagent for chemical bond formation, photoinduced electron transfer, or conformational changes required for light-sensitive signaling. Therefore, the photochemistry and photophysics of flavins have received wide attention. Fluorescence from oxidized flavin is often used to detect and track changes in flavin oxidation states. However, there have been conflicting reports over the past 45 years as to whether reduced flavin in solution has detectable fluorescence. Here, using single photon counting emission spectroscopy with rigorous sample preparation, we show definitively that reduced flavins are essentially nonfluorescent, having a quantum yield more than three orders of magnitude lower than oxidized flavin. This result will force a re-evaluation of experiments and models that assumed otherwise.
Topics: Flavins; Riboflavin; Oxidation-Reduction; Electron Transport; Flavin-Adenine Dinucleotide; Flavin Mononucleotide; Organic Chemicals
PubMed: 36689576
DOI: 10.1021/acs.biochem.2c00538 -
Pediatric Neurology Jul 2023Riboflavin transporter deficiency is a rare but severe neurometabolic disorder.
BACKGROUND
Riboflavin transporter deficiency is a rare but severe neurometabolic disorder.
METHODS
We report two siblings with pathogenic variants in SLC52A3 gene, resulting in riboflavin transporter 3 deficiency.
RESULTS
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.
CONCLUSIONS
Antenatal riboflavin supplementation is a safe and effective treatment for the prevention of symptomatic manifestations of riboflavin transporter deficiency.
Topics: Pregnancy; Male; Humans; Female; Infant; Child, Preschool; Riboflavin; Bulbar Palsy, Progressive; Vitamins; Membrane Transport Proteins; Hearing Loss, Sensorineural
PubMed: 37116404
DOI: 10.1016/j.pediatrneurol.2023.04.004 -
Neuromolecular Medicine Dec 2023AIFM1 is a mitochondrial flavoprotein involved in caspase-independent cell death and regulation of respiratory chain complex biogenesis. Mutations in the AIFM1 gene have...
AIFM1 is a mitochondrial flavoprotein involved in caspase-independent cell death and regulation of respiratory chain complex biogenesis. Mutations in the AIFM1 gene have been associated with multiple clinical phenotypes, but the effectiveness of riboflavin treatment remains controversial. Furthermore, few studies explored the reasons underlying this controversy. We reported a 7-year-old boy with ataxia, sensorimotor neuropathy and muscle weakness. Genetic and histopathological analyses were conducted, along with assessments of mitochondrial function and apoptosis level induced by staurosporine. Riboflavin deficiency and supplementation experiments were performed using fibroblasts. A missense c.1019T > C (p. Met340Thr) variant of AIFM1 was detected in the proband, which caused reduced expression of AIFM1 protein and mitochondrial dysfunction as evidenced by downregulation of mitochondrial complex subunits, respiratory deficiency and collapse of ΔΨm. The proportion of apoptotic cells in mutant fibroblasts was lower than controls after induction of apoptosis. Riboflavin deficiency resulted in decreased AIFM1 protein levels, while supplementation with high concentrations of riboflavin partially increased AIFM1 protein levels in variant fibroblasts. In addition, mitochondrial respiratory function of mutant fibroblasts was partly improved after riboflavin supplementation. Our study elucidated the pathogenicity of the AIFM1 c.1019T > C variant and revealed mutant fibroblasts was intolerant to riboflavin deficiency. Riboflavin supplementation is helpful in maintaining the level of AIFM1 protein and mitochondrial respiratory function. Early riboflavin treatment may serve as a valuable attempt for patients with AIFM1 variant.
Topics: Male; Humans; Child; Riboflavin Deficiency; Riboflavin; Mutation, Missense; Mitochondria; Mitochondrial Diseases; Apoptosis Inducing Factor
PubMed: 37603145
DOI: 10.1007/s12017-023-08750-5