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The study focuses on the green synthesis of Ag@Ag 2 O nanostructures using Padina algae extract and functionalizing them with L-tryptophan to enhance their properties as a colorimetric sensor for simultaneous detection of ultra-trace levels of thiamin and riboflavin. The nanostructures are characterized using techniques like XRD, FESEM, FTIR, TEM, AFM, and DLS to understand their morphology, structure, and interactions with target molecules. FESEM analysis revealed the hierarchical flower-like Ag@Ag 2 O nanostructures. The TEM image shows the formation of core-shell nanostructures. Also, DLS analysis and surface zeta potential spectra illustrated the aggregated nature of fabricated nanocomposites in the presence of vitamins. The study is the first to report simultaneous determination of thiamin and riboflavin using a colorimetric sensor based on Ag@Ag 2 O-L-Try nanocomposites using partial leas square (PLS). The dynamic range of thiamin and riboflavin was achieved in 0.1 mol L - 1 acetate buffer pH 4 and the ratio Ag@Ag 2 O: L-try 1:1. The Ag@Ag 2 O-L-Try sensor exhibited two linear ranges of 0.1- 1.0 and 3-350 µMol L - 1 for riboflavin and a linear range 3.0-60 µMol L - 1 for thiamin. Also, low detection limit of 1.92 µMol L - 1 and 0.048 µMol L - 1 was obtained for riboflavin and thiamin, respectively. The results indicated that the success of the method depends on the selective and sensitive colorimetric assay of the sensor along with the simultaneous determination by the PLS algorithm. Hence, the proposed technique can be used for the accurate and precise determination of vitamins in different pharmaceutical syrup and tablet samples., (© 2024. The Author(s).)

Thiamine (vitamin B 1 ) functions as an essential coenzyme in cells. Humans and other mammals cannot synthesise this vitamin de novo and thus have to take it up from their diet. Eventually, every cell needs to import thiamine across its plasma membrane, which is mainly mediated by the two specific thiamine transporters SLC19A2 and SLC19A3. Loss of function mutations in either of these transporters lead to detrimental, life-threatening metabolic disorders. SLC19A3 is furthermore a major site of drug interactions. Many medications, including antidepressants, antibiotics and chemotherapeutics are known to inhibit this transporter, with potentially fatal consequences for patients. Despite a thorough functional characterisation over the past two decades, the structural basis of its transport mechanism and drug interactions has remained elusive. Here, we report seven cryo-electron microscopy (cryo-EM) structures of the human thiamine transporter SLC19A3 in complex with various ligands. Conformation-specific nanobodies enable us to capture different states of SLC19A3's transport cycle, revealing the molecular details of thiamine recognition and transport. We identify seven previously unknown drug interactions of SLC19A3 and present structures of the transporter in complex with the inhibitors fedratinib, amprolium and hydroxychloroquine. These data allow us to develop an understanding of the transport mechanism and ligand recognition of SLC19A3., (© 2024. The Author(s).)

Vitamin Bs, a group of water-soluble compounds, are essential nutrients for almost all living organisms. However, due to their structural heterogeneity, rapid and simultaneous analysis of multiple vitamin Bs is still challenging. In this paper, it is discovered that a hetero-octameric Mycobacterium smegmatis porin A (MspA) nanopore containing a sole nickel ion-bound nitrilotriacetic acid (NTA-Ni) adapter at its pore constriction is suitable for the simultaneous sensing of different vitamin Bs, including vitamin B1 (thiamine), vitamin B3 (nicotinic acid and nicotinamide), vitamin B5 (pantothenic acid), and vitamin B6 (pyridoxine, pyridoxal, and pyridoxamine). Assisted by a custom machine learning algorithm, all seven vitamin Bs can be fully distinguished, reporting a general accuracy of 99.9%. This method was further validated in the rapid analysis of commercial cosmetics and natural food, suggesting its potential uses in food and drug administration.

In solution, analogues of the Breslow intermediate formed during catalysis by benzoylformate decarboxylase (BFDC) undergo rapid, irreversible fragmentation. The ability of BFDC to prevent this reaction and preserve its cofactor is a striking example of an enzyme 'steering' a reactive intermediate towards a productive pathway. To understand how BFDC suppresses the off-pathway reactivity of this Breslow intermediate, a clear mechanistic understanding of the fragmentation reaction is required. Here, DFT calculations reveal an unexpected mechanism for the solution-phase fragmentation that involves an intramolecular cyclization and a subsequent retro-ene reaction to release the final products. Free energy profiles demonstrate that this pathway is significantly more facile than the previously proposed mechanism that invoked Breslow intermediate enolates as intermediates. Additional computations have been performed to understand why related Breslow intermediates do not undergo analogous fragmentation reactions. Calculations performed with two closely related Breslow intermediates suggest that subtle differences in the relative values of ΔG ≠ for protonation and fragmentation dictate whether a given intermediate will fragment or not. These differences and the fragmentation mechanism unveiled in this work may have ramifications for the mechanism of BFDC and other thiamin-dependent enzymes and could provide general lessons related to the control of reactive intermediates by enzymes., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

Graphite carbon nitride (g-C 3 N 4 ) 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 Fe 3 O 4 @g-C 3 N 4 with thiamine hydrochloride (vitamin B1) via cyanuric chloride (TCT), which is a divalent covalent linker, was presented. The efficiency of Fe 3 O 4 @gC 3 N 4 @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., (© 2024. The Author(s).)

Using halloysite clay and vitamin B1 hydrochloride, a novel acidic halloysite-dendrimer catalytic composite has been developed for conversion of fructose to 5-hydroxymthylfurfural. To grow the dendritic moiety on halloysite, it was first functionalized and then reacted with melamine, epichlorohydrin and vitamin B1 hydrochloride respectively. Then, the resulting composite was treated with ZnCl 2 to furnish Lewis acid sites. Use of vitamin B1 as the cationic moiety of ionic liquid obviated use of toxic chemicals and resulted in more environmentally friendly composite. Similarly, dendritic moiety of generation 2 was also grafted on halloysite and the activity of both catalysts for conversion of fructose to 5-hydroxymthylfurfural was investigated to disclose the role of dendrimer generation. For the best catalytic composite, the reaction variables were optimized via RSM and it was revealed that use of 0.035 g catalyst per 0.1 g fructose at 95 °C furnished HMF in 96% yield in 105 min. Turnover numbers (TONs) and frequencies (TOFs) were estimated to be 10,130 and 5788 h -1 , respectively. Kinetic studies also underlined that Ea was 22.85 kJ/mol. The thermodynamic parameters of Δ H ≠ , Δ S ≠ and Δ G ≠ , were calculated to be 23 kJ/mol, - 129.2 J/mol and 72.14 kJ/mol, respectively. Notably, the catalyst exhibited good recyclability and hot filtration approved heterogeneous nature of catalysis., (© 2024. The Author(s).)

As a natural renewable biomacromolecule, lignin has some inherently interesting properties such as fluorescence, antioxidation, and antibacterial performance. However, the unsatisfactory fluorescence and biological activities have greatly limited their value-added and large-scale applications. In this work, lignin nanoparticles (LNPs) grafted with vitamin B 1 hybrid nanoparticles (LEVs) were obtained by using ethylenediamine and different contents of vitamin B 1 through a simple hydrothermal method. The chemical structure, fluorescence properties, and bioactivity were characterized to assess the effects of ethylenediamine and vitamin B 1 on the properties of LEVs. It was found that the fluorescence performance of synthesized LEV particles was improved with the increase in the amount of vitamin B 1 . The free radical scavenging rate (RSA, %) increased to 97.8%, while the antibacterial rates reached up to 99.9%. The antibacterial activity of LEV involved multiple combined mechanisms. The introduction of imine, amide groups, and positively charged VB 1 of LEV will make it easier to interact with the negatively charged bacterial phospholipid membranes and cause bacterial lysis and death. Then, the PVA/LEV hydrogel composites were prepared by the freezing-thawing method, and the results showed that PVA/LEV hydrogels had more comprehensive performance such as improved mechanical properties and antioxidant and antibacterial activities, resulting in its great potential to be used as an efficient biomedical material.

Vitamin B1 is an essential cofactor for enzymes involved in the metabolism of carbohydrates, particularly Transketolases. These enzymes are amenable to therapeutic interventions because of their specificity. In the final step of the Vitamin B1 biosynthesis pathway, Thiamine Pyrophosphokinase (TPK) converts thiamin into its active form, Thiamin Pyrophosphate (TPP), allowing researchers to investigate the functional importance of this enzyme and the pathway's dispensability in Leishmania donovani , a protozoan parasite that causes visceral leishmaniasis. In this study, various in silico , biochemical, biophysical, and cellular assays-based experiments have been conducted to identify and characterize Ld TPK, and to provide a sound platform for the discovery of potential Ld TPK inhibitors. Ld TPK structural modelling ensured high protein quality. Oxythiamine and pyrithiamine were found to bind well with Ld TPK with considerable binding energies, and MD simulation-based experiments indicated the stability of the complexation. Additionally, Ld TPK1 was found to activate ROS defense in amastigotes, and its inhibition using oxythiamine and pyrithiamine led to the growth inhibition of L. donovani promastigotes and intracellular amastigotes. These findings highlight Ld TPK as a promising target for the development of new anti-leishmanial agents. An in-depth analysis of the enzymes involved in TPP biosynthesis in L. donovani has the potential to yield novel therapeutic strategies for Leishmaniasis.Communicated by Ramaswamy H. Sarma.

Thiamine (vitamin B1) is an essential vitamin serving in its diphosphate form as a cofactor for enzymes in the citric acid cycle and pentose-phosphate pathways. Its concentration reported in the pM and nM range in environmental and clinical analyses prompted our consideration of the components used in pre-analytical processing, including the selection of filters, filter apparatuses, and sample vials. The seemingly innocuous use of glass fiber filters, glass filter flasks, and glass vials, ubiquitous in laboratory analysis of clinical and environmental samples, led to marked thiamine losses. 19.3 nM thiamine was recovered from a 100 nM standard following storage in glass autosampler vials and only 1 nM of thiamine was obtained in the filtrate of a 100 nM thiamine stock passed through a borosilicate glass fiber filter. We further observed a significant shift towards phosphorylated derivatives of thiamine when an equimolar mixture of thiamine, thiamine monophosphate, and thiamine diphosphate was stored in glass (most notably non-silanized glass, where a reduction of 54% of the thiamine peak area was observed) versus polypropylene autosampler vials. The selective losses of thiamine could lead to errors in interpreting the distribution of phosphorylated species in samples. Further, some loss of phosphorylated thiamine derivatives selectively to amber glass vials was observed relative to other glass vials. Our results suggest the use of polymeric filters (including nylon and cellulose acetate) and storage container materials (including polycarbonate and polypropylene) for thiamine handling. Losses to cellulose nitrate and polyethersulfone filters were far less substantial than to glass fiber filters, but were still notable given the low concentrations expected in samples. Thiamine losses were negated when thiamine was stored diluted in trichloroacetic acid or as thiochrome formed in situ, both of which are common practices, but not ubiquitous, in thiamine sample preparation., (© 2024. The Author(s).)

It is important to search for cytostatic compounds in order to fight cancer. One of them could be 2'-methylthiamine, which is a thiamine antimetabolite with an additional methyl group at the C-2 carbon of thiazole. So far, the cytostatic potential of 2'-methylthiamine has not been studied. We have come forward with a simplified method of synthesis using commercially available substrates and presented a comparison of its effects, as boosted by oxythiamine, on normal skin fibroblasts and HeLa cancer cells, having adopted in vitro culture techniques. Oxythiamine has been found to inhibit the growth and metabolism of cancer cells significantly better than 2'-methylthiamine (GI 50 36 and 107 µM, respectively), while 2'-methylthiamine is more selective for cancer cells than oxythiamine (SI = 180 and 153, respectively). Docking analyses have revealed that 2'-methylthiamine (Δ G -8.2 kcal/mol) demonstrates a better affinity with thiamine pyrophosphokinase than thiamine (Δ G -7.5 kcal/mol ) and oxythiamine (Δ G -7.0 kcal/mol), which includes 2'-methylthiamine as a potential cytostatic. Our results suggest that the limited effect of 2'-methylthiamine on HeLa arises from the related arduous transport as compared to oxythiamine. Given that 2'-methylthiamine may possibly inhibit thiamine pyrophosphokinase, it could once again be considered a potential cytostatic. Thus, research should be carried out in order to find the best way to improve the transport of 2'-methylthiamine into cells, which may trigger its cytostatic properties.

Thiamine diphosphate (ThDP), the bioactive form of vitamin B 1 , is an essential coenzyme needed for processes of cellular metabolism in all organisms. ThDP-dependent enzymes all require ThDP as a coenzyme for catalytic activity, although individual enzymes vary significantly in substrate preferences and biochemical reactions. A popular way to study the role of these enzymes through chemical inhibition is to use thiamine/ThDP analogues, which typically feature a neutral aromatic ring in place of the positively charged thiazolium ring of ThDP. While ThDP analogues have aided work in understanding the structural and mechanistic aspects of the enzyme family, at least two key questions regarding the ligand design strategy remain unresolved: 1) which is the best aromatic ring? and 2) how can we achieve selectivity towards a given ThDP-dependent enzyme? In this work, we synthesise derivatives of these analogues covering all central aromatic rings used in the past decade and make a head-to-head comparison of all the compounds as inhibitors of several ThDP-dependent enzymes. Thus, we establish the relationship between the nature of the central ring and the inhibitory profile of these ThDP-competitive enzyme inhibitors. We also demonstrate that introducing a C2-substituent onto the central ring to explore the unique substrate-binding pocket can further improve both potency and selectivity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The yeast thiamin pyrimidine synthase THI5p catalyzes one of the most complex organic rearrangements found in primary metabolism. In this reaction, the active site His66 and PLP are converted to thiamin pyrimidine in the presence of Fe(II) and oxygen. The enzyme is a single-turnover enzyme. Here, we report the identification of an oxidatively dearomatized PLP intermediate. We utilize oxygen labeling studies, chemical-rescue-based partial reconstitution experiments, and chemical model studies to support this identification. In addition, we also identify and characterize three shunt products derived from the oxidatively dearomatized PLP.

Transketolase catalyzes the interconversion of keto and aldo sugars. Its coenzyme is thiamine diphosphate. The binding of keto sugar with thiamine diphosphate is possible only after C2 deprotonation of its thiazole ring. It is believed that deprotonation occurs due to the direct transfer of a proton to the amino group of its aminopyrimidine ring. Using mass spectrometry, it is shown that a water molecule is directly involved in the deprotonation process. After the binding of thiamine diphosphate with transketolase and its subsequent cleavage, a thiamine diphosphate molecule is formed with a mass increased by one oxygen molecule. After fragmentation, a thiamine diphosphate molecule is formed with a mass reduced by one and two hydrogen atoms, that is, HO and H 2 O are split off. Based on these data, it is assumed that after the formation of holotransketolase, water is covalently bound to thiamine diphosphate, and carbanion is formed as a result of its elimination. This may be a common mechanism for other thiamine enzymes. The participation of a water molecule in the catalysis of the one-substrate transketolase reaction and a possible reason for the effect of the acceptor substrate on the affinity of the donor substrate for active sites are also shown.

Thiamine pyrophosphate (TPP), an essential co-factor for all species, is biosynthesised through a metabolically expensive pathway regulated by TPP riboswitches in bacteria, fungi, plants and green algae. Diatoms are microalgae responsible for c. 20% of global primary production. They have been predicted to contain TPP aptamers in the 3'UTR of some thiamine metabolism-related genes, but little information is known about their function and regulation. We used bioinformatics, antimetabolite growth assays, RT-qPCR, targeted mutagenesis and reporter constructs to test whether the predicted TPP riboswitches respond to thiamine supplementation in diatoms. Gene editing was used to investigate the functions of the genes with associated TPP riboswitches in Phaeodactylum tricornutum. We found that thiamine-related genes with putative TPP aptamers are not responsive to supplementation with thiamine or its precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP), and targeted mutation of the TPP aptamer in the THIC gene encoding HMP-P synthase does not deregulate thiamine biosynthesis in P. tricornutum. Through genome editing we established that PtTHIC is essential for thiamine biosynthesis and another gene, PtSSSP, is necessary for thiamine uptake. Our results highlight the importance of experimentally testing bioinformatic aptamer predictions and provide new insights into the thiamine metabolism shaping the structure of marine microbial communities with global biogeochemical importance., (© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.)

The eukaryotic thiamin pyrimidine synthase, THI5p, has been identified as a suicidal/single-turnover enzyme that catalyzes the conversion of its active site histidine and lysine-bound pyridoxal phosphate (PLP) to the thiamin pyrimidine (HMP-P). Here we identify the histidine and PLP fragments using bottom-up proteomics and LC-MS analysis. We also identify the active form of the iron cofactor and quantitate the oxygen requirement of the THI5p reaction. This information is integrated into a mechanistic proposal for this remarkable reaction.

Recently, a yellow Maillard pigment named pyrizepine was identified from a heated solution containing thiamine and glucose. Here, we examined the formation scheme of this pigment and some biological properties. The mass spectrometry and nuclear magnetic resonance data of pyrizepine prepared from [6-13C] glucose showed that the carbon at 6-position of glucose was inserted at 2 different positions of pyrizepine. 5-(Aminomethyl)-2-methylpyridin-4-amine (AMPA), a degradation product of thiamine, was detected in the reaction solution. The pigment also formed in the solution containing AMPA in place of thiamine. These results showed that pyrizepine formed from AMPA and C4 fragments derived from glucose. Pyrizepine showed antioxidative activities in the superoxide dismutase, 2,2-diphenyl-1-picrylhydrazyl, and H-ORAC assays. The pigment did not show mutagenicity with the Ames test. A trace amount of the pigment was detected in a pan-fried ground pork sample added glucose using liquid chromatography-tandem mass spectrometry., (© The Author(s) 2022. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.)

Thiamin (or thiamine), known as vitamin B1, represents an indispensable component of human diets, being pivotal in energy metabolism. Thiamin research depends on adequate vitamin quantification in plant tissues. A recently developed quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is able to assess the level of thiamin, its phosphorylated entities and its biosynthetic intermediates in the model plant Arabidopsis thaliana, as well as in rice. However, their implementation requires expensive equipment and substantial technical expertise. Microbiological assays can be useful in deter-mining metabolite levels in plant material and provide an affordable alternative to MS-based analysis. Here, we evaluate, by comparison to the LC-MS/MS reference method, the potential of a carefully chosen panel of yeast assays to estimate levels of total vitamin B1, as well as its biosynthetic intermediates pyrimidine and thiazole in Arabidopsis samples. The examined panel of Saccharomyces cerevisiae mutants was, when implemented in microbiological assays, capable of correctly assigning a series of wild-type and thiamin biofortified Arabidopsis plant samples. The assays provide a readily applicable method allowing rapid screening of vitamin B1 (and its biosynthetic intermediates) content in plant material, which is particularly useful in metabolic engineering approaches and in germplasm screening across or within species., (© 2022 The Authors New Phytologist © 2022 New Phytologist Foundation.)

The present study evaluated the effect of chitosan thiamine nanoparticles (TCNP) on the activation of defence responses in chickpea against stress caused by wilt pathogen, Fusarium oxysporum f. sp. ciceri (FOC), under greenhouse condition. A significant increase in enzymatic and non-enzymatic antioxidants was observed in the TCNP treated chickpea plants challenged with FOC compared to the untreated control. Histochemical staining showed high deposition of lignin in the vascular bundles of chickpea stem tissues in TCNP treated plants challenged with FOC. More than 90% protection against wilt pathogen was observed in TCNP treated chickpea plants challenged with FOC, under greenhouse condition. Higher accumulation of antioxidants and phenylpropanoids in TCNP treated challenged chickpea plants well correlates with resistance against wilt pathogen. These results suggest that the elicitation of stress response in TCNP treated chickpea during FOC interaction play a vital role in suppressing the wilt disease in chickpea., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Dry cured loins containing nitrogen (proline and ornithine) and sulfur (thiamine) compounds as precursors of aroma compounds at two concentration levels were manufactured. The effect of precursor addition on the microbiology and chemical parameters of loins was studied together with the aroma study performed by olfactometry and Free Choice Profile sensory analyses. Addition of precursors did not affect the microbial and chemical parameters, while aroma was affected when precursors were added at the highest level. The dry loin aroma profile was mainly composed by compounds 3-methylbutanal, methional, ethyl 3-methylbutanoate, 3-methylbutanoic acid, 1-octen-3-ol, 2-acetyl-1-pyrroline and 2-acetylpyrrole that contribute to musty, cooked potatoes, fruity, cheesy, mushroom, roasted and meaty odor notes. Proline and ornithine supplementation modified the loins aroma profile producing toasted odors, while the effect of thiamine supplementation on the aroma was revealed by the presence of sulfur derived compounds (methional and 2-methyl-3-(methylthio)furan) that contribute to the "cured meat odor"., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Thiamine (vitamin B1) is crucial for life and plays a central role in metabolism. It contains thiazole and pyrimidine moieties that are constructed independently and then assembled together to generate thiamine phosphate. The study of the thiazole moiety is relatively clear, but deciphering the mechanistic enzymology of thiamine pyrimidine is more difficult. This review aims to summarize the recent research progress on ThiC rearrangement, mainly including the mechanism, related enzymes, and genes involved in the rearrangement., (© 2021 Wiley-VCH GmbH.)

Three forms of pseudo-crystalline polymorph of thiamine chloride hydrochloride are dependent on hydration states. We investigated how the measurement environment affects the transition of the pseudo-crystalline polymorph, and aimed to establish a reliable method of identifying the forms clearly by IR spectrophotometry. We prepared three pseudo-crystalline forms and compared their IR spectra. In the IR spectra obtained by the potassium chloride (KCl) disk method, Form II was identified based on its characteristic absorption, but Forms I and III could not be distinguished clearly. Form I transformed to Form III after mixing with undried KCl powder, and Form III transformed to Form I by simply being left in the laboratory environment. These results suggested that the reversible transformation between Forms I and III occurred depending on the hydration status during the process of measurement, as measured by the shift in the absorption wavenumber of the primary alcohol stretching vibration. In addition, Forms I and III could not be distinguished clearly by the X-ray powder diffraction and their crystalline forms were similar plate crystals. However, in the IR spectra by the attenuated total reflection (ATR) method, the three forms could be identified based on each characteristic absorption. In summary, the ATR method does not require pretreatment for sample analysis, can be performed quickly, and is thus suitable to identify crystalline polymorph forms such as pseudo-crystalline polymorphs of thiamine chloride hydrochloride, which transform easily depending on the hydration status in a measurement environment.

A novel capillary-based fluorescence microsensor for artemisinin was developed with functional polyoxometalates (POMs) as nanozyme by a layer-by-layer self-assembly strategy. Vanadomolybdophosphoric heteropoly acid (H 5 PMo 10 V 2 O 40 , PMoV 2 ) and tungstophosphoric heteropoly acid (Na 5 PW 11 O 39 Cu, PW 11 Cu) with high peroxidase-like activity were synthesized and immobilized on capillary to catalyze artemisinin/thiamine reaction and generate the amplified fluorescence signal. The wide linear range up to 13.0 μM with the low limit of detection of 0.03 μM (S/N = 3) was achieved for the determination of artemisinin by using the proposed POMs-microsensor. The method has been successfully used to detect artemisinin in human plasma and antimalarial drugs with satisfactory accuracy. This work developed a novel capillary fluorescence microsensor with functional POMs as nanozyme, which can serve as a promising candidate in fluorescence microanalysis., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Oxythiamine (OT) and 3-deazathiamine (DAT) are the antimetabolites of thiamine. The aim of study was to compare the effects of OT and DAT pyrophosphates (-PP) on the kinetics of mammalian pyruvate dehydrogenase complex (PDHC) and the in vitro culture of HeLa cells. The kinetic study showed that 3-deazathiamine pyrophosphate (DATPP) was a much stronger competitive inhibitor ( K i = 0.0026 μM) of PDHC than OTPP ( K i = 0.025 μM). Both K i values were much lower versus K m for thiamine pyrophosphate (0.06 μM). However, DATPP added to the culture medium for the HeLa cells culture did not hamper the rate of cell growth and showed not significant impact on the viability of the cells, whereas OTPP and OT showed a significant cytostatic effect. The differences between the thiamine antivitamins in their effect on cell growth in vitro may be due to differences in physicochemical properties and difficulty in DAT transport across the cell membrane.

Rice, consumed by most people across the world, serves as a great mode for carrying nutrients. The processed, starch-rich white rice is mostly devoid of nutrients. High-pressure processing (HPP) is a technology known to produce cold gelatinizing effects in starch. This work shows the application of HPP in fortification of two types of white rice through high pressure gelatinization. The rice grains were impregnated with vitamin B 1 , calcium, and zinc. HPP treatment was carried out at the temperatures of 50 °C and 70 °C for up to 20 min. The samples were analysed for thiamine using the fluorometric method and minerals using ICP-MS. Results showed that the transfer of nutrients increases with treatment temperature and time, producing high level of nutrient uptake. HPP-fortified rice also showed stability after storage of two months. The moderate-temperature HPP has a great potential to be used as a method to produce a ready-to-eat variety of rice., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Reviewed herein are key research accomplishments of Professor Ronald Charles D. Breslow (1931-2017) throughout his more than 60 year research career. These accomplishments span a wide range of topics, most notably physical organic chemistry, medicinal chemistry, and bioorganic chemistry. These topics are reviewed, as are topics of molecular electronics and origin of chirality, which combine to make up the bulk of this review. Also reviewed briefly are Breslow's contributions to the broader chemistry profession, including his work for the American Chemical Society and his work promoting gender equity. Throughout the article, efforts are made to put Breslow's accomplishments in the context of other work being done at the time, as well as to include subsequent iterations and elaborations of the research., (Copyright © 2021 Elsevier Inc. All rights reserved.)