Genome-wide association mapping of vitamins B1 and B2 in common wheat

Vitamin B is essential for maintaining normal life activities in humans and animals who have to intake the microelement from the outside, especially from cereal products. In the present study 166 Chinese and foreign wheat cultivars planted in two environments were characterized for variation in vitamin B1 and B2 contents. A genome-wide association study(GWAS) using the wheat 90 K SNP assay identified 17 loci for vitamin B1 and 7 for vitamin B2 contents. Linear regression analysis showed a significantly positive correlation of the number of favorable alleles with vitamin B1 and B2 contents. Marker-trait associations(MTAs) at IWB43809(6AS, 0cM) and IWB69903(6AS, 13cM) were new and stable, and significantly associated with vitamin B1 content across two environments. The loci identified in this study and associated SNP markers could be used for improvement of vitamin B1 and B2 contents to obtain superior quality along with grain yield in wheat.

Clinical analysis of Wernicke encephalopathy after liver transplantation

Background:Wernicke encephalopathy(WE)is an acute neurological disease resulting from vitamin B1 deficiency,and there are only very few case reports of WE after liver transplantation.The present study aimed to investigate the clinical characteristics,etiology,magnetic resonance imaging(MRI)features,treatment and prognosis of patients with WE after liver transplantation.Methods:Twenty-three patients with WE after liver transplantation from the First Affiliated Hospital,Zhejiang University School of Medicine and Jiangxi Provincial People’s Hospital between January 2011 and December 2021 were retrospectively analyzed.Results:Among the 23 patients diagnosed with WE after liver transplantation,6(26%)had a classic triad of impaired consciousness,oculomotor palsy and ataxia,and 17(74%)had two features.The misdiagno-sis rate was 65%.After treatment with high-dose vitamin B1,19(83%)patients showed improvement,whereas 4(17%)showed no improvement,including 3 with residual short-term memory impairments and 1 with residual spatial and temporal disorientation and ataxia.Conclusions:The misdiagnosis rate is high in the early stage of WE,and the prognosis is closely asso-ciated with whether WE is diagnosed early and treated timely.High-dose glucose or glucocorticoids can trigger WE and cannot be administered before vitamin B1 treatment.Vitamin B1 is suggested to be used as a prophylactic treatment for patients with WE after liver transplantation.

Pathogenesis of pancreatic encephalopathy in severe acute pancreatitis

BACKGROUND: Pancreatic encephalopathy (PE) is a serious complication of severe acute pancreatitis (SAP). In recent years, more and more PE cases have been reported worldwide, and the onset PE in the early stage was regarded as a poor prognosis sign of SAP, but the pathogenesis of PE in SAP still has not been clarified in the past decade. The purpose of this review is to elucidate the possible pathogenesis of PE in SAP. DATA SOURCES: The English-language literature concerning PE in this review came from the Database of MEDLINE (period of 1991-2005), and the keywords of severe acute pancreatitis and pancreatic encephalopathy were used in the searching. RESULTS: Many factors were involved in the pathogenesis of PE in SAP. Pancreatin activation, excessive release of cytokines and oxygen free radicals, microcirculation abnormalities of hemodynamic disturbance, ET-1/NO ratio, hypoxemia, bacterial infection, water and electrolyte imbalance, and vitamin B1 deficiency participated in the development of PE in SAP. CONCLUSIONS: The pathogenesis of PE in SAP has not yet been fully understood. The development of PE in SAP may be a multi-factor process. To find out the possible inducing factor is essential to the clinical management of PE in SAP.

AtTHIC, a gene involved in thiamine biosynthesis in Arabidopsis thaliana

Thiamine （vitamin B1） is an essential compound for organisms. It contains a pyrimidine ring structure and a thiazole ring structure. These two moieties of thiamine are synthesized independently and then coupled together. Here we report the molecular characterization of AtTHIC, which is involved in thiamine biosynthesis in Arabidopsis. AtTHIC is similar to Escherichia coli ThiC, which is involved in pyrimidine biosynthesis in prokaryotes. Heterologous expression of AtTHIC could functionally complement the thiC knock-out mutant of E. coll. Downregulation of AtTHIC expression by T-DNA insertion at its promoter region resulted in a drastic reduction of thiamine content in plants and the knock-down mutant thicl showed albino （white leaves） and lethal phenotypes under the normal culture conditions. The thicl mutant could be rescued by supplementation of thiamine and its defect functions could be complemented by expression ofAtTHIC cDNA. Transient expression analysis revealed that the AtTHIC protein targets plastids and chloroplasts. AtTHIC was strongly expressed in leaves, flowers and siliques and the transcription of AtTHIC was downregulated by extrinsic thiamine. In conclusion, AtTHIC is a gene involved in pyrimidine synthesis in the thiamine biosynthesis pathway of Arabidopsis, and our results provide some new clues for elucidating the pathway of thiamine biosynthesis in plants.

Metabolomic Study on Vitamins B_1, B_2, and PP Supplementation to Improve Serum Metabolic Profiles in Mice under Acute Hypoxia Based on ~1H NMR Analysis

Objective To explore metabolic changes after acute hypoxia and modulating effect of vitamins B1, B2, and PP supplementation in mice exposed to acute hypoxia. Methods Fifty male Kunming mice were randomly divided into 5 groups： normal, acute hypoxia, acute hypoxia with 2, 4 and 8 time- vitamins B1, B2, and PP supplementation . All mice were fed with corresponding diets for two weeks and then were exposed to a simulated altitude of 6 000 meters for 8 h, except for the normal group. Nuclear magnetic resonance analysis was used to identify the changes of serum metabolic profiles. Results There were significant changes in some serum metabolites under induced acute hypoxia, essentially relative increase in the concentrations of lactate, sugar and lipids and decrease in ethanol. The serum levels of choline, succinate, taurine, alanine, and glutamine also increased and phosphocholine decreased in the acute hypoxia group. After vitamins B1, B2, and PP supplementation, all these metabolic changes gradually recovered. Conclusion Significant changes in serum metabolic profile were observed by metabolomics in mice exposed to acute hypoxia, and vitamins B1, B2, and PP supplementation proved to be beneficial to improving some metabolic pathways. It is suggested that the dietary intakes of vitamins B1, B2, and PP should be increased under hypoxia condition.

Evidence for altered thiamine metabolism in diabetes: Is there a potential to oppose gluco- and lipotoxicity by rational supplementation?

Growing prevalence of diabetes(type 2 as well as type 1) and its related morbidity due to vascular complications creates a large burden on medical care worldwide. Understanding the molecular pathogenesis of chronic micro-, macro- and avascular complications mediated by hyperglycemia is of crucial importance since novel therapeutic targets can be identified and tested. Thiamine(vitamin B1) is an essential cofactor of several enzymes involved in carbohydrate metabolism and published data suggest that thiamine metabolism in diabetes is deficient. This review aims to point out the physiological role of thiamine in metabolism of glucose and amino acids, to present overview of thiamine metabolism and to describe the consequences of thiamine deficiency(either clinically manifest or latent). Furthermore, we want to explain why thiamine demands are increased in diabetes and to summarise data indicating thiamine mishandling in diabetics(by review of the studies mapping the prevalence and the degree ofthiamine deficiency in diabetics). Finally, we would like to summarise the evidence for the beneficial effect of thiamine supplementation in progression of hyperglycemia-related pathology and, therefore, to justify its importance in determining the harmful impact of hyperglycemia in diabetes. Based on the data presented it could be concluded that although experimental studies mostly resulted in beneficial effects, clinical studies of appropriate size and duration focusing on the effect of thiamine supplementation/therapy on hard endpoints are missing at present. Moreover, it is not currently clear which mechanisms contribute to the deficient action of thiamine in diabetes most. Experimental studies on the molecular mechanisms of thiamine deficiency in diabetes are critically needed before clear answer to diabetes community could be given.

Determination of Vitamin B_1 in Pharmaceutical Preparations by Flow-injection Analysis with Biamperometric Detection

A new electrochemical method for the on-line determination of vitamin B1 is presented. Based on dead-stop endpoint biamperometry by using two platinum foil electrodes with an applied potential difference of 150 mV, vitamin B1 can be oxidized by hexacyanoferrate （ Ⅲ ） in a sodium hydroxide medium via a reversible indicating couple Fe（ CN）6^4- /Fe（CN）6^3- The cell current is linear with the concentration of vitamin B1 in the concentration range of 4. 0 × 10^-6-1.0 × 10^ -3 mol/L with a detection limit of 8.0 ×10 ^-7 mol/L（0. 27 μg/mL）. Most familiar excipients, ions and vitamins do not interfere with the determination of vitamin B1. The method displays the advantages of simplicity, high efficiency（ 180 samples/h）, and high selectivity, and is suitable for the determination of vitamin B1 in pharmaceutical preparations.

Comparative Study on the Leaching Dynamic Properties of Five Kinds of Microparticulate forms of Vitamin B_1

With an aim to reduce leaching of water soluble vitamins, the leaching properties of five kinds of microparticulate forms of vitamin B 1 are investigated by means of dynamic system. These microparticles include: alginate and alginate CMC microcapsules prepared by emulsion coacervation process (ECP), alginate and gelatin microcapsules prepared by spray drying process (SDP), and alginate microbound. The results show these five microparticulate forms of VB 1 can reduce leaching significantly compared to crystalline form VB 1, and the leaching rates at different intervals, diameters and encapsulation efficiencies ( EE ) are significantly different among all kinds of microparticles (ANOVA, P <0.05). The leaching properties of the five microparticles are in accord with Higuchi equation. Based on the regression equation, the half loss time ( T 50 ) is determined.In conclusion, the alginate CMC microencapsule is a potential tool to reduce leaching of water soluble vitamins.

Vitamin B1 THIAMIN REQUIRING1 synthase mediates the maintenance of chloroplast function by regulating sugar and fatty acid metabolism in rice

Vitamin B(VB1),including thiamin,thiamin monophosphate(TMP),and thiamin pyrophosphate(TPP),is an essential micronutrient for all living organisms.Nevertheless,the precise function of VB1 in rice remains unclear.Here,we described a VB1 auxotrophic mutant,chlorotic lethal seedling(cles)from the mutation of OsTH1,which displayed collapsed chloroplast membrane system and decreased pigment content.OsTH1 encoded a phosphomethylpyrimidine kinase/thiamin-phosphate pyrophosphorylase,and was expressed in various tissues,especially in seedlings,leaves,and young panicles.The VB1 content in cles was markedly reduced,despite an increase in the expression of VB1 synthesis genes.The decreased TPP content affected the tricarboxylic acid cycle,pentose phosphate pathway,and de novo fatty acid synthesis,leading to a reduction in fatty acids(C16:0 and C18:0)and sugars(sucrose and glucose)of cles.Additionally,irregular expression of chloroplast membrane synthesis genes led to membrane collapse.We also found that alternative splicing and translation allowed OsTH1 to be localized to both chloroplast and cytosol.Our study revealed that OsTH1 was an essential enzyme in VB1 biosynthesis and played crucial roles in seedling growth and development by participating in fatty acid and sugar metabolism,providing new perspectives on VB1 function in rice.

Wernicke encephalopathy in children and adolescents

Background:Wernicke encephalopathy is caused by thiamine(vitamin B1)defi ciency.It is generally considered to be a disease of adult alcoholics.However,it is known to occur in the pediatric population and in non-alcoholic conditions.Data sources:We searched PubMed with the key words Wernicke,thiamine,pediatric,children and adolescents and selected publications that were deemed appropriate.Results:The global prevalence rates of hunger,poverty and resultant nutrient deprivation have decreased in the 21st century.However,several scenarios which may predispose to Wernicke encephalopathy may be increasingly prevalent in children and adolescents such as malignancies,intensive care unit stays and surgical procedures for the treatment of obesity.Other predisposing conditions include magnesium defi ciency and defects in the SLC19A3 gene causing thiamine transporter-2 deficiency.The classic triad consists of encephalopathy,oculomotor dysfunction and gait ataxia but is not seen in a majority of patients.Treatment should be instituted immediately when the diagnosis is suspected clinically without waiting for laboratory confi rmation.Common magnetic resonance findings include symmetric T2 hyperintensities in dorsal medial thalamus,mammillary bodies,periaqueductal gray matter,and tectal plate.Conclusions:Wernicke encephalopathy is a medical emergency.Delay in its recognition and treatment may lead to significant morbidity,irreversible neurological damage or even death.This article aims to raise the awareness of this condition among pediatricians.