Thiamine Research Articles

Nutrient Consumption Patterns of Saccharomyces cerevisiae and Their Application in Fruit Wine Fermentation

This study aimed to evaluate the nutritional requirements of Saccharomyces cerevisiae to improve low ethanol production in some fruit wines. The growth kinetics, ethanol production and nutrient requirements of S. cerevisiae were analyzed in chemically defined media. The results revealed that Ca2⁺, Fe2⁺, Co2⁺, Mo2⁺, Cu2⁺ and BO₃3− were predominantly utilized during the late lag phase, whereas free amino acids, nicotinic acid, calcium pantothenate, Na⁺ and Mg2⁺ were mainly consumed during the logarithmic phase. Compared with the control medium, supplementation with threonine, inositol, calcium pantothenate, thiamine hydrochloride, riboflavin, biotin, MgSO4 or KH2PO4 significantly increased the ethanol content by 1.10-fold (p < 0.05). Furthermore, adding key nutrients to noni-, guava- and mango juice significantly shortened the fermentation time and increased the final alcohol content of the fruit wines (p < 0.05). This study provides scientific insights and effective methods for shortening fermentation time and increasing alcohol content with S. cerevisiae in some fruit wines.

Full-length 16S rRNA gene amplicon analysis of gut microbiota in pigs fed with different diets in growing and finishing stages

The present study utilized full-length 16S rRNA gene sequencing to investigate the impact of dietary protein content on the composition and function of gut microbiota, and to analyze the gut microbiota of pigs in the growing (30 kg) and finishing (120 kg) stages under different feeding conditions. The results indicated that the gut microbiota was significantly different between pigs fed high- and low-protein diets. Comparing fecal samples from pigs at 30 and 120 kg, pigs at 30 kg showed a significant increase in the relative abundance of Clostridium butyricum, whereas at 120 kg, the abundance of Lactobacillus reuteri and Lactobacillus johnsonii decreased. To access the functional profiles and metabolic pathways based on amplicon sequence variants (ASVs), the microbiome of the 120 kg exhibited significant enrichments in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to metabolism-related category, including Alanine, aspartate and glutamate metabolism, Tyrosine and Thiamin metabolism, and Inositol phosphate metabolism. Meanwhile, analysis using the MetaCyc database showed that the metabolic pathways of the 30 kg group were significantly distinct when compared to the 120 kg of fecal samples. Overall, the findings indicated that the gut microbiota composition and function in the 30 and 120 kg fecal samples were markedly shaped by different dietary protein levels.

Sputum Metabolomic Signature and Dynamic Change of Cough Variant Asthma.

Cough variant asthma (CVA), a common reason for chronic cough, is a globally prevalent and burdensome condition. The heterogeneity of CVA and a lack of knowledge concerning the exact molecular pathogenesis has hampered its clinical management. This study presented the first sputum metabolome of CVA patients, revealed the dynamic change during treatment, and explored biomarkers related to the occurrence and treatment response of CVA. We found arginine biosynthesis, purine metabolism, and pyrimidine metabolism pathways were enriched in CVA compared to healthy controls. Part of metabolic disturbances could be reversed by anti-asthmatic medication. The levels of dipeptides/tripeptides (alanyltyrosine, Gly-Tyr-Ala, Ala-Leu, and Thr-Leu) were significantly associated with sputum Neu% or Eos% of CVA patients. Differential metabolites pre-treatment between effective and ineffective groups enriched in purine metabolism, thiamine metabolism, and arginine metabolism. 2-isopropylmalate was down-regulated in CVA patients and increased after treatment, and effective group had a lower 2-isopropylmalate level pre-treatment. Random forest and logistic regression models identified glutathione, thiamine phosphate, alanyltyrosine, and 2'-deoxyadenosine as markers for distinguishing CVA from healthy controls (all AUC > 0.8). Thiamine phosphate might also be promising for predicting therapy responsiveness (AUC = 0.684). These findings implied that disturbed mitochondrial energy metabolism and imbalanced oxidation-reduction homeostasis probably underlay the metabolic pathogenesis of CVA.

Evanescent hormesis effect induced by environmentally relevant PFOS to marine Chlorella sp.

Perfluorooctanesulfonic acid (PFOS) is widely detected in the aquatic environment. More attentions were paid to its acute biotoxicity at high-dose concentrations, whereas the actual long-term effect (hormesis or inhibition of growth) of PFOS with environmental concentrations on marine phytoplankton remains unclear. In this study, marine Chlorella sp. was exposed to PFOS at low concentrations (100 ng/L, 10 μg/L, and 1 mg/L) for 26 days. The hormesis effect disappeared at the population level on Day 18, but persisted at the molecular and cellular levels on Day 24, suggesting that the stimulatory hormetic effect induced by low-level PFOS (approximating environmental concentrations) does not persist throughout algal life cycle at population level. The 100 ng/L and 1 mg/L PFOS treatments caused algal cell to swell and shrink, respectively. The low-level PFOS treatments could accelerate cells apoptosis and induce cell necrosis at 100 ng/L. Specifically, the energy metabolism associated with carbohydrate metabolism and amino acid metabolism was significantly up-regulated as well as the reduced chlorophyll content (related to the down-regulation of porphyrin metabolism) to combat the 100 ng/L PFOS rather than be engaged in divide and growth. Additionally, the decreased biomass in the 100 ng/L treatment was also attributed to certain proteins associated with down-regulations of carotenoid biosynthesis, thiamine metabolism, non-homologous end-joining, and nitrogen metabolism along with the increased oxidative stress. Our findings provide a new insight into the long-term ecological effect of PFOS at environmental concentrations.

In Vitro Mucoadhesive Features of Gliadin Nanoparticles Containing Thiamine Hydrochloride.

Gliadins have aroused significant interest in the last decade as suitable biomaterials for food and pharmaceutical applications. In particular, the oral route is the preferred method of administration for gliadin-based formulations, due to the affinity of this biomaterial for the gut mucosa. However, up to now, this has been demonstrated only by means of in vivo or ex vivo studies. This is why, in this study, various in vitro techniques were employed in order to evaluate the ability of polymeric nanoparticles, made up of a commercial grade of the protein and an etheric surfactant, to interact with porcine gastric mucin. The nanosystems were also used for the encapsulation of thiamine hydrochloride, used as a model of a micronutrient. The resulting systems were characterized by a mean diameter of ~160-170 nm, a narrow size distribution when 0.2-0.6 mg/mL of thiamine was used, and an encapsulation efficiency between 30 and 45% of the drug initially employed. The incubation of the gliadin nanosystems with various concentrations of porcine gastric mucin evidenced the ability of the carriers to interact with the mucus glycoprotein, showing a decreased Zeta potential after a 4 h incubation (from ~-30 to -40 mV), while demonstrating that the encapsulation of the drug did not affect its bioadhesive features. Altogether, these data support the conceivable application of gliadin nanoparticles as formulations for the oral administration of bioactive compounds.

Whole-Genome Bisulfite Sequencing (WGBS) Analysis of Gossypium hirsutum under High-Temperature Stress Conditions

Background: DNA methylation is an important part of epigenetic regulation and plays an important role in the response of plants to adverse stress. Methods: In this study, whole-genome bisulfite sequencing (WGBS) was performed on the high-temperature-resistant material Xinluzao 36 and the high-temperature-sensitive material Che 61–72 at 0 h and 12 h under high-temperature stress conditions. Results: The results revealed that the Gossypium hirsutum methylation levels of CG and CHG (H = A, C, or T) decreased after the high-temperature stress treatment, and the methylation level of the A subgenome was significantly greater than that of the D subgenome. The methylation level of CHH increased, and the methylation level of CHH in the D subgenome was significantly greater than that in the A subgenome after high-temperature stress treatment. The methylation density of CG is lower than that of CHG and CHH, and the methylation density of the middle region of chromosomes is greater than that of both ends, which is opposite to the distribution density of genes. There were 124 common differentially methylated genes in the CG, CHG, and CHH groups, and 5130 common DEGs and differentially methylated genes were found via joint analysis with RNA-seq; these genes were significantly enriched in the biosynthesis of plant hormones, thiamine metabolism, glutathione metabolism, and tyrosine metabolism pathways. DNA methylation did not affect the expression of many genes (accounting for 85.68% of the differentially methylated genes), DNA methylation-promoted gene expression was located mainly in the downstream region of the gene or gene body, and the expression of inhibitory genes was located mainly in the upstream region of the gene. Conclusions: This study provides a theoretical basis for further exploration of the gene expression and functional regulatory mechanism of G. hirsutum DNA methylation under high-temperature stress conditions.

The genomes of Australian wild limes

Australian wild limes occur in highly diverse range of environments and are a unique genetic resource within the genus Citrus. Here we compare the haplotype-resolved genome assemblies of six Australian native limes, including four new assemblies generated using PacBio HiFi and Hi-C sequencing data. The size of the genomes was between 315 and 391 Mb with contig N50s from 29.5 to 35 Mb. Gene completeness of the assemblies was estimated to be from 98.4 to 99.3% and the annotations from 97.7 to 98.9% based upon BUSCO, confirming the high contiguity and completeness of the assembled genomes. High collinearity was observed among the genomes and the two haplotype assemblies for each species. Gene duplication and evolutionary analysis demonstrated that the Australian citrus have undergone only one ancient whole-genome triplication event during evolution. The highest number of species-specific and expanded gene families were found in C. glauca and they were primarily enriched in purine, thiamine metabolism, amino acids and aromatic amino acids metabolism which might help C. glauca to mitigate drought, salinity, and pathogen attacks in the drier environments in which this species is found. Unique genes related to terpene biosynthesis, glutathione metabolism, and toll-like receptors in C. australasica, and starch and sucrose metabolism genes in both C. australis and C. australasica might be important candidate genes for HLB tolerance in these species. Expanded gene families were not lineage specific, however, a greater number of genes related to plant-pathogen interactions, predominantly disease resistant protein, was found in C. australasica and C. australis.

Thiamine-modified octamolybdate catalyzes solvent-free stereoselective olefin epoxidation with TBHP

Simple stirring of an acidic aqueous solution (pH=3) containing sodium molybdate and thiamine hydrochloride (VB1) at room temperature resulted in an octamolybdate-containing VB1 (MoB1) material as an efficient and cost-effective epoxidation catalyst using tert‑butyl hydroperoxide (TBHP) under solvent-free condition. The stereospecific stilbene oxidation (>99 %) observed in the presence of MoB1 can be originated from the steric hindrance of some groups on the thiamine molecule and π–π stacking interactions of its pyrimidine and/or thiazole rings with phenyl rings of stilbenes. Further olefins such as cyclooctene, indene, 1-octene, and styrenes are efficiently oxidized using MoB1/TBHP catalytic system. The catalyst is composed of two thiaminium dications (C12H18N4OS)2+ and one Mo8O264– tetraanion based on different characterization techniques and chemical compositional analyses. Field Emission Scanning Electron Microscope (FE-SEM) images shows a sheet-like nanostructure for MoB1 comprising layers with thicknesses ranging from 50 to 500 nm. It exhibits a heterogeneous nature in catalysis evidenced by hot filtration test and ICP-OES analysis. X-ray photoelectron spectroscopy (XPS) indicates minor contributions of Mo in the oxidation states +V and +IV in addition to MoVI attributed to partial electron transfer from VB1 to Mo8O264–. The scavenging experiments support the presence of radical species during catalysis, while, they do not damage the structural integrity of the MoB1 catalyst based on the recycling experiments and FT-IR spectra.

Effects of a food supplement containing phosphatidylserine on cognitive function in Chinese older adults with mild cognitive impairment: A randomized double-blind, placebo-controlled trial

BackgroundPhosphatidylserine (PS) and α-Linolenic acid (ALA), are positively associated with cognitive function, but their combination effects and possible mechanisms remain unclear. We aimed to explore the effects on cognition and potential mechanism of the supplements. MethodsThis randomized, double-blind, placebo-controlled trial recruited 190 MCI patients in Tianjin, China, and randomly assigned in intervention group and placebo group. Each group consumed two capsules every day for 12 months. Each capsule for intervention group contains 144 mg ALA, 31.5 mg PS and 3.6 mg Ginkgo total flavonoids as main functional components, with 0.48 mg Vitamin B1 (as thiamine hydrochloride), 0.48 mg Vitamin B6 (as pyridoxine hydrochloride) and 90 μg folic acid as supplement. Capsules for placebo group were identical but contain no active ingredients. Cognitive function, serum n-3 polyunsaturated fatty acids (PUFAs) and neurotransmitters were assessed at baseline and 12 months. Linear mixed effects model and causal mediation analysis were conducted to explore the effects and potential mechanism of the intervention. ResultsA total of 190 participants (mean [SD] age, 67.95 [5.62] years; 70 (36.8 %) male and 120 (63.2 %) female) were randomized to the placebo group (n = 95) and intervention group (n = 95). Compared with placebo group, the intervention group had statistically significant improvements in arithmetic testing (β, 0.688; 95 % CI, 0.103–1.274), the similarity test (β, 1.070; 95 % CI, 0.472–1.667) and short-term memory (β, 0.600; 95 % CI, 0.399–0.800). Besides, the intervention group had statistically significant increases in serum ALA (β, 1.620; 95 % CI, 0.967–2.265), DHA (β, 2.797; 95 % CI, 1.075–4.532), EPA (β, 1.472; 95 % CI, 0.296–2.643), acetylcholine (β, 0.441; 95 % CI, 0.415–0.468), GABA (β, 0.009; 95 % CI, 0.001–0.016) and 5-HT (β, 0.160; 95 % CI, 0.081–0.238) compared to the placebo group. And the intervention may improve short-term memory by increasing serum ALA levels (average causal mediation effect = 0.132, 95 % CI, 0.053–0.225) with 19.7 % mediation proportion. ConclusionsThis food supplement containing phosphatidylserine could improve different cognitive functions of MCI patients, especially short-term memory, and increase serum n-3 PUFAs and neurotransmitters levels. Serum ALA level might play a mediation role.

Synthesis and structural characterization of new chitosan-thiamine hydrochloride molecular complexes

Chitosan is one of the natural cationic polymers used for drug delivery due to its unique properties as an antimicrobial and antioxidant agent. In this work, three new molecular complexes were obtained by mechanically grinding a mixture of chitosan and thiamine hydrochloride in weight ratios of 4:1, 3:2, and 1:1, with a few drops of acetic acid and sodium citrate solutions. Complementary analyses, including X-ray powder diffraction, differential thermal analyses, thermogravimetric analyses, Fourier transform infrared spectroscopy, and CP/MAS 13C NMR, were performed to characterize the new molecular complexes. X-ray diffraction revealed the transformation of chitosan from a semi-crystalline to an amorphous state after mechanochemical grinding. Infrared spectroscopy showed changes in the vibrations of the functional groups CO, OH, and NH in the structure of the developed compounds, indicating the interconnection of the components. Solid-state nuclear magnetic resonance spectroscopy recorded shifts of the resonance lines present in the ball-milled samples, compared to the initial compounds, along with the appearance of new lines, supporting the formation of chitosan-thiamine hydrochloride complexes. Thermal analyses confirmed the successful development of new molecular complexes by the appearance of two new exothermic signals at lower temperatures than those observed for chitosan.

Fe3O4@gC3N4@Thiamine: a novel heterogeneous catalyst for the synthesis of heterocyclic compounds and microextraction of tebuconazole in food samples

Graphite carbon nitride (g-C3N4) is a two-dimensional nano-sheet with electronic properties, which shows unique characteristics with high chemical and thermal stability in its structure. The functionalization of these compounds through covalent bonding is an important step towards significantly improving their properties and capabilities. To achieve this goal, a novel strategy for the covalent functionalization of Fe3O4@g-C3N4 with thiamine hydrochloride (vitamin B1) via cyanuric chloride (TCT), which is a divalent covalent linker, was presented. The efficiency of Fe3O4@gC3N4@Thiamine as a heterogeneous organic catalyst in the synthesis of spirooxindole-pyran derivatives and 2-amino-4H-pyran under solvent-free conditions was evaluated and the yields of high-purity products were presented. In addition, easy recycling and reuse for seven consecutive cycles without significant reduction in catalytic activity are other features of this catalyst. Moreover, the performance of the prepared sorbent in the microextraction technique (herein, magnetic solid phase extraction) was studied. The tebuconazole was selected as the target analyte. The target analyte was extracted and determined by HPLC–UV. Under the optimum condition, the linear range of the method (LDR) was estimated in the range of 0.2–100 μg L−1 (the coefficient of determination of 0.9962 for tebuconazole). The detection limit (LOD) of the method for tebuconazole was calculated to be 0.05 µg L−1. The limit of quantification (LOQ) of the method was also estimated to be 0.16 µg L−1. In order to check the precision of the proposed method, the intra-day and inter-day relative standard deviations (RSD%) were calculated, which were in the range of 1.5- 2.8%. The method was used for the successful extraction and determination of tebuconazole in tomato, cucumber, and carrot samples.

Interfacial double-coordination effect reconstructing anode/electrolyte interface for long-term and highly reversible Zn metal anodes

The highly reversible electrochemical deposition and dissolution of zinc metal anode is a critical feature for the practical application of aqueous zinc-ion batteries (ZIBs). Nevertheless, this process is seriously hindered by the uncontrollable electrodeposition and interfacial side reactions caused by thermodynamically unstable anode/electrolyte interface (AEI). Guided by the electrode/electrolyte interface chemistry, thiamine hydrochloride (TH) as a novel additive is added into traditional ZnSO4 (ZS) electrolyte to induce sustained reversible Zn deposition/stripping. Spectroscopic characterizations and electrochemical tests reveal that TH can adsorbed on the anode surface owning to the strong double-coordination effect between N, S atoms and Zn atoms via Zn-N and Zn-S chemical bonds. In addition, there are polar hydroxyl groups in the TH molecular structure which can form hydrogen bonds with water molecules. Thus, the adsorbed TH layer can not only guide the diffusion of Zn2+ ions and achieve dendrite-free electrodeposition process, but also prevent intimate contact between water and anode to suppress the occurrence of interface side reactions. Based on these benefits, the TH additive achieves an ultra-long stable cycle lifespan to 2045 h at 1 mA cm−2 and 1 mAh cm−2. Even at a higher current density of 5 mA cm−2, prolonged cycling performance about 773 h is demonstrated. Besides, the assembled Zn//NVO full cells reveal excellent capacity retention and rate performance under practical conditions, highlighting the efficient and reliable coordination effect of TH additive at the AEI.

Low expression of thiamine pyrophosphokinase-1 contributes to brain susceptibility to thiamine deficiency.

Thiamine deficiency is a well-known risk factor for the development of severe encephalopathy, such as Wernicke encephalopathy and Korsakoff syndrome, but the underlying mechanism is still mysterious. This study aims to investigate the expression levels of thiamine metabolism genes in different tissues and their impact on brain susceptibility to thiamine deficiency. The mRNA and protein levels of four genes known to be associated with thiamine metabolism: thiamine pyrophosphokinase-1 (Tpk), Solute carrier family 19 member 2 (Slc19a2), Slc19a3, and Slc25a19, in the brain, kidney, and liver of mice were examined. Thiamine diphosphate (TDP) levels were measured in these tissues. Mice were subjected to dietary thiamine deprivation plus pyrithiamine (PTD), a specific TPK inhibitor, or pyrithiamine alone to observe the reduction in TDP and associated pathological changes. TPK mRNA and protein expression levels were lowest in the brain compared to the kidney and liver. Correspondingly, TDP levels were also lowest in the brain. Mice treated with PTD or pyrithiamine alone showed an initial reduction in brain TDP levels, followed by reductions in the liver and kidney. PTD treatment caused significant neuron loss, neuroinflammation, and blood-brain barrier disruption, whereas dietary thiamine deprivation alone did not. TPK expression level is the best indicator of thiamine metabolism status. Low TPK expression in the brain appears likely to contribute to brain susceptibility to thiamine deficiency, underscoring a critical role of TPK in maintaining cerebral thiamine metabolism and preventing thiamine deficiency-related brain lesions.

Development of Novel Pyridine and Pyrimidine Clubbed Bisindoles as Inhibitors of AKT Pathway

AbstractIndoles and their derivatives have long been studied for their anticancer properties. Breast cancer has been treated using indole‐3‐carbinol, Indirubins, and many other naturally occurring indoles as well as their synthesized equivalents. It has been determined that the AKT pathway is a prospective target for therapeutic strategies in the treatment of breast cancer. The dysregulation of AKT pathway frequently promotes cell proliferation, survival, and resistance to apoptosis. We synthesized a novel group of bisindole clubbed pyridine and pyrimidine derivatives 5(a–l) using water as the solvent and thiamine hydrochloride as the catalyst. Compounds 5 a, 5 c, 5 d, 5 e, and 5 f are the most active against MCF‐7 cells, with an IC50 values of 2.48±0.39, 1.35±0.13, 3.36±0.53, 4.05±0.61 and 1.91±0.28 μM, respectively. Further, in silico docking of the active compound 5 c had the highest binding energy of −10.59 kcal/mol. Additionally, molecular dynanamics simulations were performed for better understanding the mode of interaction of ligand and protein. In conclusion, we have synthesized bisindoles using thiamine hydrochloride as a catalyst that target AKT pathway in breast cancer cells.

Report of a novel recurrent homozygous variant c.620A>T in three unrelated families with thiamine metabolism dysfunction syndrome 5 and review of literature.

Biallelic variants in thiamine pyrophosphokinase 1 ( TPK1 ) are known to cause thiamine metabolism dysfunction syndrome 5 (THMD5). This disorder is characterized by neuroregression, ataxia and dystonia with basal ganglia abnormalities on neuroimaging. To date, 27 families have been reported with THMD5 due to variants in TPK1 . We ascertained three individuals from three unrelated families. Singleton exome sequencing was performed on all three individuals, followed by in silico mutagenesis of the mutant TPK protein. Additionally, we reviewed the genotypic and phenotypic information of 27 previously reported individuals with THMD5. Singleton exome sequencing revealed a novel homozygous variant c.620A>T p.(Asp207Val) in TPK1 (NM_022445.4) in all three individuals. In silico mutagenesis of the mutant protein revealed a decrease in protein stability and altered interactions with its neighboring residues compared to the wild-type protein. Thus, based on strikingly similar clinical and radiological findings compared to the previously reported individuals and with the support of in silico mutagenesis findings, the above-mentioned variant appears to be the probable cause for the condition observed in the affected individuals in this study. We report a novel homozygous variant in TPK1 , which appears to be recurrent among the Indian population.

Dietary silymarin improves performance by altering hepatic lipid metabolism and cecal microbiota function and its metabolites in late laying hens

BackgroundLiver lipid dysregulation is one of the major factors in the decline of production performance in late-stage laying hens. Silymarin (SIL), a natural flavonolignan extracted from milk thistle, is known for its hepatoprotective and lipid-lowering properties in humans. This study evaluates whether SIL can provide similar benefits to late-stage laying hens. A total of 480 68-week-old Lohmann Pink laying hens were randomly assigned into 5 groups, each group consisting of 6 replicates with 16 hens each. The birds received a basal diet either without silymarin (control) or supplemented with silymarin at concentrations of 250, 500, 750, or 1,000 mg/kg (SIL250, SIL500, SIL750, SIL1000) over a 12-week period.ResultsThe CON group exhibited a significant decline in laying rates from weeks 9 to 12 compared to the initial 4 weeks (P = 0.042), while SIL supplementation maintained consistent laying rates throughout the study (P > 0.05). Notably, the SIL500 and SIL750 groups showed higher average egg weight than the CON group during weeks 5 to 8 (P = 0.049). The SIL750 group had a significantly higher average daily feed intake across the study period (P < 0.05), and the SIL500 group saw a marked decrease in the feed-to-egg ratio from weeks 5 to 8 (P = 0.003). Furthermore, the SIL500 group demonstrated significant reductions in serum ALT and AST levels (P < 0.05) and a significant decrease in serum triglycerides and total cholesterol at week 12 with increasing doses of SIL (P < 0.05). SIL also positively influenced liver enzyme expression (FASN, ACC, Apo-VLDL II, FXR, and CYP7A1; P < 0.05) and altered the cecal microbiota composition, enhancing species linked to secondary bile acid synthesis. Targeted metabolomics identified 9 metabolites predominantly involved in thiamin metabolism that were significantly different in the SIL groups (P < 0.05).ConclusionsOur study demonstrated that dietary SIL supplementation could ameliorate egg production rate in late stage laying hens, mechanistically, this effect was via improving hepatic lipid metabolism and cecal microbiota function to achieve. Revealed the potentially of SIL as a feed supplementation to regulate hepatic lipid metabolism dysregulation. Overall, dietary 500 mg/kg SIL had the best effects.Graphical

Genome assembly and variant analysis of two Saccharomyces cerevisiae strains isolated from stingless bee pollen

Products from stingless bees are rich reservoirs of microbial diversity, including yeasts with fermentative potential. Previously, two Saccharomyces cerevisiae strains, JP14 and IP9, were isolated from Jataí (Tetragonisca angustula) and Iraí (Nannotrigona testaceicornis) bees, respectively, aiming at mead production. Both strains presented great osmotic and sulfite tolerance, and ethanol production, although they have a high free amino nitrogen demand. Herein, their genomes were sequenced, assembled, and annotated, and the variants were compared to the S. cerevisiae S288c reference strain. The final assembly of IP9 and JP14 presented high N50 and BUSCO scores, and more than 6430 protein-coding genes. Additionally, nQuire predicted the ploidy of IP9 as diploid, but the results were not enough to determine the ploidy of JP14. The mitochondrial genomes of IP9 and JP14 presented the same gene content as S288c but the genes were rearranged and fragmented in different patterns. Meanwhile, the genes with mutations of high impact (e.g., indels, gain of stop codon) for both yeasts were enriched for transmembrane transport, electron transfer, oxidoreductase, heme binding, fructose, mannose, and glucose transport, activities related to the respiratory chain and sugar metabolism. The IP9 strain presented copy number gains in genes related to sugar transport and cell morphogenesis; in JP14, genes were enriched for disaccharide metabolism and transport, response to reactive oxygen species, and polyamine transport. On the other hand, IP9 presented copy number losses related to disaccharide, thiamine, and aldehyde metabolism, while JP14 presented depletions related to disaccharide, oligosaccharide, asparagine, and aspartate metabolism. Notably, both strains presented a killer toxin gene, annotated from the assembling of unmapped reads, representing a potential mechanism for the control of other microorganisms population in the environment. Therefore, the annotated genomes of JP14 and IP9 presented a high selective pressure for sugar and nitrogen metabolism and stress response, consistent with their isolation source and fermentative properties.

Comparative Genomic and Genetic Evidence on a Role for the OarX Protein in Thiamin Salvage.

Salvage pathways for thiamin and its thiazole and pyrimidine moieties are poorly characterized compared to synthesis pathways. A candidate salvage gene is oarX, which encodes a short-chain dehydrogenase/reductase. In diverse bacteria, oarX clusters on the chromosome with genes of thiamin synthesis, salvage, or transport and is preceded by a thiamin pyrophosphate riboswitch. Thiamin and its moieties can undergo oxidations that convert a side-chain hydroxymethyl group to a carboxyl group, or the thiazole ring to a thiazolone, causing a loss of biological activity. To test if OarX participates in salvage of the carboxyl or thiazolone products, we used a genetic approach in Corynebacterium glutamicum ATCC 14067, which is auxotrophic for thiamin's pyrimidine moiety. This strain could not utilize the pyrimidine carboxyl derivative. This excluded a role in salvaging this product and narrowed the function search to metabolism of the carboxyl or thiazolone derivatives of thiamin or its thiazole moiety. However, a ΔthiG (thiazole auxotroph) strain was not rescued by any of these derivatives. Nor did deleting oarX affect rescue by the physiological pyrimidine and thiazole precursors of thiamin. These findings reinforce the genomic evidence that OarX has a function in thiamin metabolism and rule out five logical possibilities for what this function is.

Thiazolium salt mimics the non-coenzyme effects of vitamin B1 in rat synaptosomes

Long-term studies have confirmed a causal relationship between the development of neurodegenerative processes and vitamin B1 (thiamine) deficiency. However, the biochemical mechanisms underlying the high neurotropic activity of thiamine are not fully understood. At the same time, there is increasing evidence that vitamin B1, in addition to its coenzyme functions, may have non-coenzyme activities that are particularly important for neurons. To elucidate which effects of vitamin B1 in neurons are due to its coenzyme function and which are due to its non-coenzyme activity, we conducted a comparative study of the effects of thiamine and its derivative, 3-decyloxycarbonylmethyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride (DMHT), on selected processes in synaptosomes. The ability of DMHT to effectively compete with thiamine for binding to thiamine-binding sites on the plasma membrane of synaptosomes and to participate as a substrate in the thiamine pyrophosphokinase reaction was demonstrated. In experiments with rat brain synaptosomes, unidirectional effects of DMHT and thiamine on the activity of the pyruvate dehydrogenase complex (PDC) and on the incorporation of radiolabeled [2–14C]pyruvate into acetylcholine were demonstrated. The observed effects of thiamine and DMHT on the modulation of acetylcholine synthesis can be explained by suggesting that both compounds, which interact in cells with enzymes of thiamine metabolism, are phosphorylated and exert an inhibitory/activating effect (concentration-dependent) on PDC activity by affecting the regulatory enzymes of the complex. Such effects were not observed in the presence of structural analogues of thiamine and DMHT without a 2-hydroxyethyl substituent at position 5 of the thiazolium cycle. The effect of DMHT on the plasma membrane Ca-ATPase was similar to that of thiamine. At the same time, DMHT showed high cytostatic activity against neuroblastoma cells.

Cytotoxicity and bioavailability assessment from micellar system based Thiamine-Phospholipid complexes

Poor absorption (3–5 %) of thiamine hydrochloride (TH), is primarily concerned with impaired permeability across intestinal mucosa. To modulate the permeability of TH, a phospholipid (PL) interaction-based hydrophobic complex of thiamine was investigated. Using the solvent evaporation approach, thiamine-phospholipid complexes (TPCs) were prepared between free bases of thiamine and PLs in the weight ratio (1:1, 1:2, and 2:1) and characterized using FTIR, spectrophotometry, XRD, and conductometric methods. Electrical conductivity and partition coefficient studies demonstrated that TPCs were hydrophobic transformations formed via PL interaction with a free thiamine base. TPCs were embedded into the micellar system (Tween20/Ethanol), characterized by electrical conductivities and zeta-sizing studies, and exploited in its micellar delivery system design. TPC 1:1 & 1:2 had much lower conductivity than TH and its physical mixture (TH/PL) in the Tween20/Ethanol environment diluted with an aqueous phase. The average size of micellar systems loaded with TPC (10 % w/w) was within the range of 12–25 nm, and conductivity was in the range of 122-130µS/cm. In vitro release characterization from complexes and their micellar systems in HCl 1.2, phosphate buffer (PB) 6.8, and bidistilled water showed a delayed release pattern. TPC modulated the intestinal permeability of thiamine as revealed from ex vivo studies. TPC (1:1) and its micellar system produced significant differences in drug permeability (p < 0.001) compared to TH and physical mixture. Pharmacokinetic assessment of the micellar system of complexes in Wistar rats showed that the TPC (1:1) loaded micellar system produced a 2.4-fold enhancement of AUC(0−24) over (TH) followed by oral administration. Assessment of cell viability in mouse fibroblast cell line (L929) culture showed that TPC or micellar system did not inhibit cell growth and was safe at various concentration levels. TPc complexes developed using phospholipid complexation yield hydrophobic transformation in TH and their micellar system-based delivery modulates the intestinal permeability and bioavailability enhancement.