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Vitamin Deficiencies – Diagnosis and Treatment
Published in Jennifer Doley, Mary J. Marian, Adult Malnutrition, 2023
More than 90% of dietary riboflavin is in the form of flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN), while the remaining 10% is composed of the free form and riboflavin glycosides or esters. Although not routinely measured in healthy people, a stable and sensitive measure of riboflavin deficiency is the erythrocyte glutathione reductase activity coefficient (EGRAC). The most appropriate EGRAC thresholds to assess riboflavin status are uncertain. An EGRAC of 1.2 or less is usually used to indicate adequate riboflavin status, 1.2–1.4 to indicate marginal deficiency, and greater than 1.4 to indicate deficiency. However, it is important to note that a higher EGRAC does not necessarily correlate with the degree of riboflavin deficiency. In addition, the EGRAC cannot be used in people with glucose-6-phosphate dehydrogenase deficiency, which is present in about 10% of Black people.13
Fluorescent Technology in the Assessment of Metabolic Disorders in Diabetes
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Elena V. Zharkikh, Viktor V. Dremin, Andrey V. Dunaev
The second group includes some of the most intense fluorophores that exist in biological tissues, involved in cellular metabolic processes – the reduced form of nicotinamide adenine dinucleotide (NADH), flavins (FAD, etc.), and strongly fluorescent lipopigments (lipofuscin). NADH is excited in a wavelength range between 330 and 370 nm. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) with excitation maxima around 380 and 450 nm also contribute to tissue autofluorescence [5,6]. The fluorescence of the coenzymes NADH and FAD separately or together is used in the assessment of mitochondrial respiratory chain function.
Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
The flavin coenzymes including flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are derivatives of riboflavin (vitamin B2). Like the nicotinamide coenzymes, the flavin coenzymes participate in redox reactions that affect energy nutrients in the citric acid cycle and in the electron transport system.
Current biochemical treatments of mitochondrial respiratory chain disorders
Published in Expert Opinion on Orphan Drugs, 2019
Robert Heaton, Lauren Millichap, Fatima Saleem, Jennifer Gannon, Gemma Begum, Iain P. Hargreaves
Riboflavin or vitamin B2 acts as a precursor of FMN (Flavin mononucleotide) and FAD (flavin adenine dinucleotide) which are prosthetic groups for MRC complex I and II, respectively [33]. Riboflavin obtained from the diet enters the mitochondria from the cytosol by means of specific transporters and is then converted into either FMN and FAD [33]. Therefore, riboflavin transporters are essential for the maintenance of mitochondrial riboflavin homeostasis which if impaired can result in MRC dysfunction with a consequent impairment of oxidative phosphorylation [33]. This is illustrated in cases of Brown Vialetto Van Laere disease which is associated with riboflavin transporter detects and a concomitant impairment in the activities MRC complex I and II in patient fibroblasts (skin cells) [34]. Patients with this riboflavin transporter defect have been reported to show clinical improvement following high dose riboflavin therapy [35]. Furthermore, patients with mutations in the ACAD9, the FADH2 dependent MRC complex I assembly factor have also been reported to show clinical improvement following treatment with riboflavin [36]. Commensurate with this clinical improve, an increased in MRC complex I activity was also reported in fibroblasts from patients with this condition following supplementation with riboflavin [37]. It has been suggested that the increase in the intra-mitochondrial FAD concentration following riboflavin supplementation may improve the folding capacity of mutant flavoprotein assembly factors [36].
Multifunctional fluorescent titania nanoparticles: green preparation and applications as antibacterial and cancer theranostic agents
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mina Masoudi, Mansour Mashreghi, Elaheh Goharshadi, Azadeh Meshkini
The FE-SEM images (Figure 2(A, B)) showed that nanoparticles have spherical morphology which was further confirmed by AFM (Figure 2(C)). The PSD (particle size distribution) plots were obtained by determining the size of 50 particles for each samples (using Digimizer 4.0, MedCalc Software, Belgium). The average particles size was <30 nm for both samples. The EDS analysis showed the distinct peaks for Ti and oxygen elements with an atomic percent of 12.75% (25.11%) and 43.76% (72.38%), respectively for FTN (HTN). The Au peak was originated from the gold coating of the samples for obtaining images. The C and N peaks with an atomic percent of 25.85% and 16.31%, respectively, were observed for FTN which could be related to the presence of flavin mononucleotide (FMN) and/or bacterial enzymes. These peaks did not exist for HTN.
Riboswitches as therapeutic targets: promise of a new era of antibiotics
Published in Expert Opinion on Therapeutic Targets, 2023
Emily Ellinger, Adrien Chauvier, Rosa A. Romero, Yichen Liu, Sujay Ray, Nils G. Walter
Most antibiotics have been developed against protein targets (exception being those targeting the ribonucleoprotein complex of the ribosome); however, as we look toward finding novel, innovative strategies for drug discovery, RNA targets may hold the key to a new era of antibiotics [32]. Specifically, most high-priority pathogens listed by the CDC and WHO contain riboswitches (Figure 1 and Table 1) [5,33], with the thiamine pyrophosphate (TPP) riboswitch alone found in nearly all of them [18]. For example, MRSA is a ‘serious’ threat recognized by the CDC and known to contain multiple riboswitches, including those binding TPP, lysine, and flavin mononucleotide (FMN) [18].