Riboflavin (vitamin B2) is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide, which are essential coenzymes in all free-living organisms. Riboflavin biosynthesis in many Bacteria but not in Archaea is controlled by FMN-responsive riboswitches. We identified a novel bifunctional riboflavin kinase/regulator (RbkR), which controls riboflavin biosynthesis and transport ge...

The effect of caffeine complexation with riboflavin on the kinetics of riboflavin photolysis in the pH range 2.0-10.5 has been studied. The photolysis of riboflavin solutions (5x10(-5) M) was carried out in the presence of caffeine (0.5-2.5x10(-4) M) using a visible radiation source. A specific multicomponent spectrophotometric method was used for the determination of riboflavin and photoproduc...

Micrococcus luteus produced 29 muM riboflavin during growth on 6.5 mM pyridine but not during growth on other substrates. On the basis of the results of radiolabelling studies, riboflavin was not directly synthesized from pyridine. Pyridine may interfere with riboflavin biosynthesis or elicit a general stress response in M. luteus.

Riboflavin requirements were studied in six non-pregnant, 12 pregnant, 11 lactating women, 20 children aged 4-6 years and 14 children aged 10-12 years. All subjects initially were riboflavin-deficient with erythrocyte glutathione reductase activation coefficient (EGR-AC) of >=1.3, confined in a metabolic ward and repleted with increasing doses of riboflavin during four 10 or 8 day feeding perio...

Eremothecium ashbyii is one of a number of organisms which produce considerable amounts of riboflavin, most of which is secreted by the cells into the medium (Guilliermond, 1935). The investigations of Schopfer (1944) and Schopfer and Guilloud (1945) resulted in the development of a synthetic medium for this organism which permitted growth and riboflavin production to occur under chemically def...

Biochemical riboflavin status was measured in 68 preterm infants who were receiving either human milk or a preterm infant formula (containing riboflavin, 1.8 mg/l) during the first few weeks of life. The relation between riboflavin status, type of diet, and time of introduction of a multivitamin supplement containing riboflavin was analysed and the duration of phototherapy was recorded. Those w...

BACKGROUND National survey data of erythrocyte glutathione reductase activation coefficient (EGRac) indicate that suboptimal riboflavin status may be a problem in all population age groups, but the cutoff for deficiency is controversial. In addition, the effectiveness of different biomarkers of riboflavin status has not been critically evaluated. OBJECTIVE We aimed to assess the effectiveness...

The use of the filamentous fungus, Ashbya gossypii, to improve riboflavin production at an industrial scale is described in this paper. A riboflavin overproducing strain was isolated by ultraviolet irradiation. Ten minutes after spore suspensions of A. gossypii were irradiated by ultraviolet light, a survival rate of 5.5% spores was observed, with 10% of the surviving spores giving rise to ribo...

A study of 10 mature crossbred, ovariectomized gilts was conducted to determine whether riboflavin secretion by porcine uteri is regulated by estrogen and progesterone. A second experiment was performed to determine whether secretion of riboflavin occurs in pregnant animals in a temporal and quantitative pattern similar to that in nonpregnant animals. In the hormonal induction experiment, it wa...

Purpose. To compare stromal riboflavin concentration after three corneal cross-linking (CXL) imbibition procedures: standard (EpiOff), transepithelial corneal (EpiOn), and iontophoresis-assisted technique (Ionto) using 0.1% hypotonic riboflavin phosphate. Methods. Randomized open-label pilot clinical study. Twelve corneas/12 patients with advanced keratoconus were randomly divided into 4 groups...