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1,057 result(s) for "thiamin"
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The rice PALE1 homolog is involved in the biosynthesis of vitamin B1
CRISPR/Cas9‐induced mutation in the OsPALE1 gene. (a) Phenotypes of a representative Ospale1 mutant compared with the wild type (WT) at a similar developmental stage. (b) Schematic diagram of the OsPALE1 gene and DNA sequences around the editing site. [Colour figure can be viewed at wileyonlinelibrary.com] DNA sequence analyses revealed that all 10 transgenic plants have the same biallelic mutation: an A or G single‐nucleotide insertion at the same site (Figure 1b). [...]these plants may be derived from the same Ospale1 line during callus regeneration. [...]Arabidopsis and rice may have distinct mechanisms to regulate the expression of vitamin B1 biosynthesis genes.
Thiamin pyrophosphokinase is required for thiamin cofactor activation in Arabidopsis
Thiamin pyrophosphate (TPP) is an essential enzyme cofactor required for the viability of all organisms. Whether derived from exogenous sources or through de novo synthesis, thiamin must be pyrophosphorylated for cofactor activation. The enzyme thiamin pyrophosphokinase (TPK) catalyzes the conversion of free thiamin to TPP in plants and other eukaryotic organisms and is central to thiamin cofactor activation. While TPK activity has been observed in a number of plant species, the corresponding gene/protein has until now not been identified or characterized for its role in thiamin metabolism. Here we report the functional identification of two Arabidopsis TPK genes, AtTPK1 and AtTPK2 and the enzymatic characterization of the corresponding proteins. AtTPK1 and AtTPK2 are biochemically redundant cytosolic proteins that are similarly expressed throughout different plant tissues. The essential nature of TPKs in plant metabolism is reflected in the observation that while single gene knockouts of either AtTPK1 or AtTPK2 were viable, the double mutant possessed a seedling lethal phenotype. HPLC analysis revealed the double mutant is nearly devoid of TPP and instead accumulates the precursor of the TPK reaction, free thiamin. These results suggest that TPK activity provides the sole mechanism by which exogenous and de novo derived thiamin is converted to the enzyme cofactor TPP.
Optimizing thiamine pyrophosphate metabolism enhances crop yield and quality
Global food security requires sustainable strategies to improve crop yield and nutrition. Although thiamine pyrophosphate (TPP), the active form of vitamin B1, plays a central role in energy metabolism, redox homeostasis, and carbon assimilation, its contribution to crop yield and quality remains largely unexplored. Here, we show that ZmTPK2 , a thiamine pyrophosphokinase encoded by the major ear length QTL qKB6.2a , is a key regulator of maize yield. We reveal that ZmTPK2 -dependent TPP homeostasis synchronizes three cornerstones of plant metabolism: mitochondrial tricarboxylic acid (TCA) cycle activity, chloroplast-mediated carbon fixation, and nitrogen utilization. Both overexpression and knockout of ZmTPK2 disrupt yield and grain quality, revealing that optimal TPP levels are required for productivity. Exogenous TPP supplementation increases grain yield in maize, rice, and rapeseed up to 9.8%. These findings identify TPP metabolism as a key regulatory pathway for metabolic engineering, biofortification, and global food security solutions. Thiamine pyrophosphate (TPP) is the biologically active form of vitamin B1 and servers as an essential metabolic cofactor regulating energy production, redox homeostasis, and carbon assimilation. Here, the authors show that optimizing TPP metabolism can enhance yield and quality in maize, rice and rapeseed.
Protective effects of adenosine triphosphate, thiamin, thiamin pyrophosphate, and their combination against linezolid-induced renal injury and lactic acidosis in rats
Linezolid, an oxazolidinone antibiotic effective against Gram-positive pathogens, may cause nephrotoxicity and lactic acidosis during prolonged therapy. This experimental study investigated the protective effects of adenosine triphosphate (ATP), thiamin, thiamin pyrophosphate (TPP), and their combination (ATTP) on linezolid-induced renal injury and lactic acidosis in rats. Thirty-six male Wistar rats were randomly divided into six groups (  = 6): healthy control (HG), linezolid only (LZD), ATP+linezolid (ATLZD), thiamin + linezolid (TLZD), TPP+linezolid (TPLZD), and ATP+thiamin + TPP+linezolid (ATTPL). Linezolid (125 mg/kg, orally) was administered twice daily, while ATP (4 mg/kg), thiamin (20 mg/kg), and TPP (20 mg/kg) were given intraperitoneally once daily for 28 days. At the end of treatment, kidney tissues were examined for oxidative stress markers [malondialdehyde (MDA), total glutathione (tGSH), superoxide dismutase (SOD), catalase (CAT)] and histopathology, and blood samples were analyzed for blood urea nitrogen (BUN), creatinine, and lactate. Linezolid increased oxidative stress, suppressed antioxidants, and elevated BUN, creatinine, and lactate levels. ATP partially improved the oxidative balance in renal tissue but failed to prevent hyperlactatemia and impaired renal function. Thiamin did not produce significant changes. TPP markedly improved oxidative stress markers and reduced renal dysfunction. The triple combination provided the most pronounced protection, restoring antioxidant defenses, kidney function, and lactate levels to near-control values. Histopathological evaluation revealed marked tubular degeneration, interstitial hemorrhage, and mononuclear cell infiltration in the linezolid group, which were markedly improved by TPP and combination therapy. These findings indicate that TPP protects against linezolid-induced nephrotoxicity and lactic acidosis, with its efficacy further enhanced by ATP.
Rice for Food Security: Revisiting Its Production, Diversity, Rice Milling Process and Nutrient Content
Rice is food consumed regularly and is vital for the food security of over half the world’s population. Rice production on a global scale is predicted to rise by 58 to 567 million tonnes (Mt) by 2030. Rice contains a significant number of calories and a wide variety of essential vitamins, minerals, and other nutritional values. Its nutrients are superior to those found in maize, wheat, and potatoes. It is also recognised as a great source of vitamin E and B5 as well as carbohydrates, thiamine, calcium, folate, and iron. Phytic acid and phenols are among the phenolic compounds found in rice, alongside sterols, flavonoids, terpenoids, anthocyanins, tocopherols, tocotrienols, and oryzanol. These compounds have been positively linked to antioxidant properties and have been shown to help prevent cardiovascular disease and diabetes. This review examines recent global rice production, selected varieties, consumption, ending stocks, and the composition of rice grains and their nutritional values. This review also includes a new method of paddy storage, drying, and grading of rice. Finally, the environmental impacts concerning rice cultivation are discussed, along with the obstacles that must be overcome and the current policy directions of rice-producing countries.
Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis
The mutualistic symbiosis involving Glomeromycota, a distinctive phylum of early diverging Fungi, is widely hypothesized to have promoted the evolution of land plants during the middle Paleozoic. These arbuscular mycorrhizal fungi (AMF) perform vital functions in the phosphorus cycle that are fundamental to sustainable crop plant productivity. The unusual biological features of AMF have long fascinated evolutionary biologists. The coenocytic hyphae host a community of hundreds of nuclei and reproduce clonally through large multinucleated spores. It has been suggested that the AMF maintain a stable assemblage of several different genomes during the life cycle, but this genomic organization has been questioned. Here we introduce the 153-Mb haploid genome of Rhizophagus irregularis and its repertoire of 28,232 genes. The observed low level of genome polymorphism (0.43 SNP per kb) is not consistent with the occurrence of multiple, highly diverged genomes. The expansion of mating-related genes suggests the existence of cryptic sex-related processes. A comparison of gene categories confirms that R. irregularis is close to the Mucoromycotina. The AMF obligate biotrophy is not explained by genome erosion or any related loss of metabolic complexity in central metabolism, but is marked by a lack of genes encoding plant cell wall-degrading enzymes and of genes involved in toxin and thiamine synthesis. A battery of mycorrhiza-induced secreted proteins is expressed in symbiotic tissues. The present comprehensive repertoire of R. irregularis genes provides a basis for future research on symbiosis-related mechanisms in Glomeromycota.
Beriberi, White Rice, and Vitamin B
In this comprehensive account of the history and treatment of beriberi, Kenneth Carpenter traces the decades of medical and chemical research that solved the puzzle posed by this mysterious disease. Caused by the lack of a minute quantity of the chemical thiamin, or vitamin B1 in the diet, beriberi is characterized by weakness and loss of feeling in the feet and legs, then swelling from fluid retention, and finally heart failure. Western doctors working in Asia after 1870 saw it as the major disease in native armed forces and prisons. It was at first attributed to miasms (poisonous vapors from damp soil) or to bacterial infections. In Java, chickens fed by chance on white rice lost the use of their legs. On brown rice, where the grain still contained its bran and germ, they remained healthy. Studies in Javanese prisons then showed beriberi also occurring where white (rather than brown) rice was the staple food. Birds were used to assay the potency of fractions extracted from rice bran and, after 20 years, highly active crystals were obtained. In another 10 years their structure was determined and \"thiamin\" was synthesized. Beriberi is a story of contested knowledge and erratic scientific pathways. It offers a fascinating chronicle of the development of scientific thought, a history that encompasses public health, science, diet, trade, expanding empires, war, and technology. From the preface: This is a medical detective story: beginning with the investigation of a disease that has killed or crippled at least a million people, and then following up clues that ranged much wider. One outcome was the production of a synthetic chemical that we now, nearly all of us, consume in small quantities each day in our food. The detectives had a variety of professions and spoke different languages. Their work ranged from studying the health of laborers in a primitive jungle to the painstaking dissection of individual grains of rice under a microscope. The integrated story of their struggles and successes, culled from old volumes in scattered libraries, forms the subject of this book.
The wide phenotypic spectrum of thiamine metabolism dysfunction syndrome 5 and its treatment
Thiamine metabolism dysfunction syndrome 5 (TMDS5) is a rare inborn error of metabolism caused by variants in TPK1 , leading to reduced TPK levels. This enzyme is crucial for the production of thiamine pyrophosphate, the active form of thiamine, a vital coenzyme in numerous metabolic pathways. The clinical presentation exhibits a diverse range of manifestations. In this review, we explore reported cases in the literature and present two cases representing the extremes of the clinical spectrum: recurrent ataxia and Leigh syndrome. The former phenotype follows a milder course. The second one is characterized by early onset and severe symptoms, including dystonia, epilepsy, and developmental regression, progressing rapidly to severe disability with high mortality. Typically, children exposed to infectious or traumatic triggers display episodes marked by ataxia and dystonia, with periods of good health or only mild disabilities in between. Treatment with the phosphorylated thiamine active bioform, TPP, is more effective in the recurrent ataxia form, especially when initiated promptly at symptom onset. Further studies are needed to identify available biomarkers and establish correlations between different variants, severity, and treatment response.
B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review
The B-vitamins comprise a group of eight water soluble vitamins that perform essential, closely inter-related roles in cellular functioning, acting as co-enzymes in a vast array of catabolic and anabolic enzymatic reactions. Their collective effects are particularly prevalent to numerous aspects of brain function, including energy production, DNA/RNA synthesis/repair, genomic and non-genomic methylation, and the synthesis of numerous neurochemicals and signaling molecules. However, human epidemiological and controlled trial investigations, and the resultant scientific commentary, have focused almost exclusively on the small sub-set of vitamins (B9/B12/B6) that are the most prominent (but not the exclusive) B-vitamins involved in homocysteine metabolism. Scant regard has been paid to the other B vitamins. This review describes the closely inter-related functions of the eight B-vitamins and marshals evidence suggesting that adequate levels of all members of this group of micronutrients are essential for optimal physiological and neurological functioning. Furthermore, evidence from human research clearly shows both that a significant proportion of the populations of developed countries suffer from deficiencies or insufficiencies in one or more of this group of vitamins, and that, in the absence of an optimal diet, administration of the entire B-vitamin group, rather than a small sub-set, at doses greatly in excess of the current governmental recommendations, would be a rational approach for preserving brain health.
Comparative genomics of Rhizophagus irregularis, R. cerebriforme, R. diaphanus and Gigaspora rosea highlights specific genetic features in Glomeromycotina
Glomeromycotina is a lineage of early diverging fungi that establish arbuscular mycorrhizal (AM) symbiosis with land plants. Despite their major ecological role, the genetic basis of their obligate mutualism remains largely unknown, hindering our understanding of their evolution and biology. We compared the genomes of Glomerales (Rhizophagus irregularis, Rhizophagus diaphanus, Rhizophagus cerebriforme) and Diversisporales (Gigaspora rosea) species, together with those of saprotrophic Mucoromycota, to identify gene families and processes associated with these lineages and to understand the molecular underpinning of their symbiotic lifestyle. Genomic features in Glomeromycotina appear to be very similar with a very high content in transposons and protein-coding genes, extensive duplications of protein kinase genes, and loss of genes coding for lignocellulose degradation, thiamin biosynthesis and cytosolic fatty acid synthase. Most symbiosis-related genes in R. irregularis and G. rosea are specific to Glomeromycotina. We also confirmed that the present species have a homokaryotic genome organisation. The high interspecific diversity of Glomeromycotina gene repertoires, affecting all known protein domains, as well as symbiosis-related orphan genes, may explain the known adaptation of Glomeromycotina to a wide range of environmental settings. Our findings contribute to an increasingly detailed portrait of genomic features defining the biology of AM fungi.