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Journal of Microbiology and... Dec 2023Biochemical gut metabolism of dietary bioactive compounds is of great significance in elucidating health-related issues at the molecular level. In this study, a human...
Biochemical gut metabolism of dietary bioactive compounds is of great significance in elucidating health-related issues at the molecular level. In this study, a human gut bacterium cleaving C-C glycosidic bond was screened from puerarin conversion to daidzein, and a new, gram-positive -glycoside-deglycosylating strain, sp. MRG-IFC3, was isolated from human fecal sample under anaerobic conditions. Though MRG-IFC3 biotransformed isoflavone -glycoside, it could not metabolize other -glycosides, such as vitexin, bergenin, and aloin. As evident from the production of the corresponding aglycons from various 7--glucosides, MRG-IFC3 strain also showed 7--glycoside cleavage activity; however, flavone 3--glucoside icariside II was not metabolized. In addition, for mechanism study, -glycosyl bond cleavage of puerarin by MRG-IFC3 strain was performed in DO GAM medium. The complete deuterium enrichment on C-8 position of daidzein was confirmed by H NMR spectroscopy, and the result clearly proved for the first time that daidzein is produced from puerarin. Two possible reaction intermediates, the quinoids and 8-dehydrodaidzein anion, were proposed for the production of daidzein-8d. These results will provide the basis for the mechanism study of stable -glycosidic bond cleavage at the molecular level.
Topics: Humans; Bacteria; Glycosides; Isoflavones; Glucosides; Feces
PubMed: 37789701
DOI: 10.4014/jmb.2308.08021 -
ELife Mar 2024The physical basis of phase separation is thought to consist of the same types of bonds that specify conventional macromolecular interactions yet is unsatisfyingly often...
The physical basis of phase separation is thought to consist of the same types of bonds that specify conventional macromolecular interactions yet is unsatisfyingly often referred to as 'fuzzy'. Gaining clarity on the biogenesis of membraneless cellular compartments is one of the most demanding challenges in biology. Here, we focus on the chromosome passenger complex (CPC), that forms a chromatin body that regulates chromosome segregation in mitosis. Within the three regulatory subunits of the CPC implicated in phase separation - a heterotrimer of INCENP, Survivin, and Borealin - we identify the contact regions formed upon droplet formation using hydrogen/deuterium exchange mass spectrometry (HXMS). These contact regions correspond to some of the interfaces seen between individual heterotrimers within the crystal lattice they form. A major contribution comes from specific electrostatic interactions that can be broken and reversed through initial and compensatory mutagenesis, respectively. Our findings reveal structural insight for interactions driving liquid-liquid demixing of the CPC. Moreover, we establish HXMS as an approach to define the structural basis for phase separation.
Topics: Phase Separation; Cell Cycle Proteins; Chromosomes; Mitosis; Cytoskeleton; Chromosome Segregation; Aurora Kinase B
PubMed: 38456462
DOI: 10.7554/eLife.92709 -
European Journal of Pharmaceutical... Aug 2023The discovery of cephalosporin and demonstration of its improved stability in aqueous solution, as well as enhanced in vitro activity against penicillin-resistant...
The discovery of cephalosporin and demonstration of its improved stability in aqueous solution, as well as enhanced in vitro activity against penicillin-resistant organisms, were major breakthroughs in the development of β-lactam antibiotics. Although cephalosporins are more stable with respect to hydrolytic degradation than penicillins, they still experience a variety of chemical transformations. The present study offers an insight into the rates and mechanisms of ceftriaxone degradation at the therapeutic concentration in water, a mixture of water and deuterium oxide, and deuterium oxide itself at the neutral pH. Specific ceftriaxone degradation products were observed in aged samples (including a previously unreported dimer-type species), and by comparing the degradation rates in HO and DO, the observation of a kinetic isotope effect provided some valuable insight as to the nature of the initial ceftriaxone degradation. The effect of protium to deuterium isotope change on the degradation kinetics of ceftriaxone was evaluated using the method of initial rates based on HPLC analysis as well as by quantitative H NMR spectroscopy. Moreover, computational analysis was utilized to get a molecular insight into chemical processes governing the ceftriaxone degradation and to rationalize the stabilizing effect of replacing HO with DO.
Topics: Deuterium Oxide; Deuterium; Ceftriaxone; Kinetics; Water; Cephalosporins
PubMed: 37160178
DOI: 10.1016/j.ejps.2023.106461 -
Biology Jan 2024Histidine residues play crucial roles in shaping the function and structure of proteins due to their unique ability to act as both acids and bases. In other words, they... (Review)
Review
Histidine residues play crucial roles in shaping the function and structure of proteins due to their unique ability to act as both acids and bases. In other words, they can serve as proton donors and acceptors at physiological pH. This exceptional property is attributed to the side-chain imidazole ring of histidine residues. Consequently, determining the acid-base dissociation constant (a) of histidine imidazole rings in proteins often yields valuable insights into protein functions. Significant efforts have been dedicated to measuring the pa values of histidine residues in various proteins, with nuclear magnetic resonance (NMR) spectroscopy being the most commonly used technique. However, NMR-based methods encounter challenges in assigning signals to individual imidazole rings and require a substantial amount of proteins. To address these issues associated with NMR-based approaches, a mass-spectrometry-based method known as histidine hydrogen-deuterium exchange mass spectrometry (His-HDX-MS) has been developed. This technique not only determines the pa values of histidine imidazole groups but also quantifies their solvent accessibility. His-HDX-MS has proven effective across diverse proteins, showcasing its utility. This review aims to clarify the fundamental principles of His-HDX-MS, detail the experimental workflow, explain data analysis procedures and provide guidance for interpreting the obtained results.
PubMed: 38248468
DOI: 10.3390/biology13010037 -
Journal of Magnetic Resonance Open Dec 2023In light of the growing interest deuterium metabolic imaging, hyperpolarized C, N, He, and Xe imaging, as well as P spectroscopy and imaging in large animals on...
In light of the growing interest deuterium metabolic imaging, hyperpolarized C, N, He, and Xe imaging, as well as P spectroscopy and imaging in large animals on clinical MR scanners, we demonstrate the use of a (radio)frequency converter system to allow X-nuclear MR spectroscopy (MRS) and MR imaging (MRI) on standard clinical MRI scanners without multinuclear capability. This is not only an economical alternative to the multinuclear system (MNS) provided by the scanner vendors, but also overcomes the frequency bandwidth problem of some vendor-provided MNSs that prohibit users from applications with X-nuclei of low magnetogyric ratio, such as deuterium (6.536 MHz/Tesla) and N (-4.316 MHz/Tesla). Here we illustrate the design of the frequency converter system and demonstrate its feasibility for P (17.235 MHz/Tesla), C (10.708 MHz/Tesla), and N MRS and MRI on a clinical MRI scanner without vendor-provided multinuclear hardware.
PubMed: 38046796
DOI: 10.1016/j.jmro.2023.100118 -
Organic Letters Aug 2023Nirmatrelvir and GC373 inhibit the SARS-CoV-2 3CL protease and hinder viral replication in COVID-19. As nirmatrelvir in Paxlovid is oxidized by cytochrome P450 3A4,...
Nirmatrelvir and GC373 inhibit the SARS-CoV-2 3CL protease and hinder viral replication in COVID-19. As nirmatrelvir in Paxlovid is oxidized by cytochrome P450 3A4, ritonavir is coadministered to block this. However, ritonavir undesirably alters the metabolism of other drugs. Hydrogens can be replaced with deuterium in nirmatrelvir and GC373 to slow oxidation. Results show that deuterium slows oxidation of nirmatrelvir adjacent to nitrogen by ∼40% and that the type of warhead can switch the site of oxidative metabolism.
Topics: Humans; Ritonavir; SARS-CoV-2; Deuterium; COVID-19; Antiviral Agents
PubMed: 37523471
DOI: 10.1021/acs.orglett.3c02140 -
ACS Medicinal Chemistry Letters Dec 2023The unexpected oxidation of nitrogenous heterocycles by aldehyde oxidase (AO) may be addressed by the substitution of deuterium for hydrogen adjacent to the heterocycle...
The unexpected oxidation of nitrogenous heterocycles by aldehyde oxidase (AO) may be addressed by the substitution of deuterium for hydrogen adjacent to the heterocycle nitrogen atom. Enaminones are versatile intermediates in the synthesis of nitrogenous heterocycles. We report that heretofore inaccessible monodeuterated enaminones of the general structure RC(=O)CH=CDNMe may be synthesized from methyl ketones and DCOMe with high isotopic fidelity and efficient utilization of deuterium.
PubMed: 38116410
DOI: 10.1021/acsmedchemlett.3c00395 -
Analytical Chemistry Oct 2023Rapid antifungal susceptibility testing (AFST) is urgently needed in clinics to treat invasive fungal infections with the appropriate antifungal drugs and to slow the...
Rapid antifungal susceptibility testing (AFST) is urgently needed in clinics to treat invasive fungal infections with the appropriate antifungal drugs and to slow the emergence of antifungal resistance. However, current AFST methods are time-consuming (24-48 h) due to the slow growth of fungal cells and the methods not being able to work directly for clinical samples. Here, we demonstrate rapid AFST by measuring the metabolism in single fungal cells using stimulated Raman scattering imaging and deuterium probing. Distinct metabolic responses were observed in to different classes of antifungal drugs: while the metabolism was inhibited by amphotericin B, it was stimulated by azoles (fluconazole and voriconazole) and micafungin. Accordingly, we propose metabolism change as a biomarker for rapid AFST. The results were obtained in 4 h with 100% categorical agreement with the gold standard broth microdilution test. In addition, a protocol was developed for direct AFST from positive blood cultures. This method overcomes the limitation of slow growth in conventional methods and has the potential for the rapid diagnosis of candidemia and other clinical fungal infections.
Topics: Antifungal Agents; Candida; Spectrum Analysis, Raman; Microbial Sensitivity Tests; Fluconazole
PubMed: 37815933
DOI: 10.1021/acs.analchem.3c02243 -
Environment International Jun 2024Fusion energy investigation has stepped to a new stage adopting deuterium and tritium as fuels from the previous stage concentrating hydrogen plasma physics. Special... (Review)
Review
Fusion energy investigation has stepped to a new stage adopting deuterium and tritium as fuels from the previous stage concentrating hydrogen plasma physics. Special radiation safety issues would be introduced during this stage. In addition to industrial and military uses, tungsten is also regarded as the most promising plasma facing material for fusion reactors. During the operation of fusion reactors, tungsten-based plasma facing materials can be activated via neutron nuclear reaction. Meanwhile, activated tungsten dust can be produced when high-energy plasma interacts with the tungsten-based plasma facing materials, namely plasma wall interaction. Activated tungsten dust would be an emerging environmental pollutant with radiation toxicity containing various radionuclides in addition to the chemical toxicity of tungsten itself. Nonetheless, the historical underestimation of its environmental availability has led to limited research on tungsten compared to other environmental contaminants. This paper presents the first systematic review on the safety issue of emerging activated tungsten dust, encompassing source terms, environmental behaviors, and health effects. The key contents are as follows: 1) to detail the source terms of activated tungsten dust from aspects of tungsten basic properties, generation mechanism, physical morphology and chemical component, radioactivity, as well as potential release pathways, 2) to illustrate the environmental behaviors from aspects of atmospheric dispersion and deposition, transformation and migration in soil, as well as plant absorption and distribution, 3) to identify the toxicity and health effects from aspects of toxicity to plants, distribution in human body, as well as health effects by radiation and chemical toxicity, 4) based on the research progress, research and development issues needed are also pointed out to better knowledge of safety issue of activated tungsten dust, which would be beneficial to the area of fusion energy and ecological impact caused by the routine tungsten related industrial and military applications.
Topics: Tungsten; Dust; Humans
PubMed: 38810497
DOI: 10.1016/j.envint.2024.108774 -
Chemistry (Weinheim An Der Bergstrasse,... Aug 2023In this study, incorporation of one deuterium atom was achieved by H-D exchange of one of the two identical methylene protons in various dihalomethanes (halogen=Cl, Br,...
In this study, incorporation of one deuterium atom was achieved by H-D exchange of one of the two identical methylene protons in various dihalomethanes (halogen=Cl, Br, and I) through a rapid-mixing microflow reaction of lithium diisopropylamide as a strong base and deuterated methanol as a deuteration reagent. Generation of highly unstable carbenoid intermediate and suppression of its decomposition were successfully controlled under high flow-rate conditions. Monofunctionalization of diiodomethane afforded various building blocks composed of boryl, stannyl, and silyl groups. The monodeuterated diiodomethane, which served as a deuterated C1 source, was subsequently subjected to diverted functionalization methods to afford various products including biologically important molecules bearing isotope labelling at specific positions and homologation products with monodeuteration.
PubMed: 37300319
DOI: 10.1002/chem.202301738