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Talanta May 2024This work presents a novel application of gas-diffusion microextraction (GDME) combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD)...
This work presents a novel application of gas-diffusion microextraction (GDME) combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the comprehensive analysis of volatile carbonyl compounds released from wood-based panels. GDME is a simple, fast, and environmentally friendly technique that allows the simultaneous extraction and derivatization of volatile carbonyls directly from solid samples. Commercial particleboards were analysed together with particleboard panels specifically produced using controlled conditions, materials, and reagents, to evaluate the differences in the emission profile of volatile carbonyl compounds. The effect of different production parameters, such as the type of wood particle, resin, and moisture content, on the emission profile of volatile carbonyls from particleboards was investigated using principal component analysis (PCA). The results showed that GDME-HPLC-DAD could successfully differentiate particleboards according to their emission of carbonyl compounds, such as formaldehyde, furfural, benzaldehyde, and other aliphatic carbonyls. Besides the differences on the emission of formaldehyde caused by the type of resin used, UF (urea-formaldehyde) and mUF (UF fortified with melamine), it was found that pine (Pinus pinaster Ait.) particleboards exhibit higher emissions of compounds such as acetaldehyde or hexanal when compared to the higher emissions of compounds such as furfural or benzaldehyde on the recycled particleboards.
PubMed: 38402738
DOI: 10.1016/j.talanta.2024.125818 -
Microbiology Spectrum Apr 2024The rising rate of antimicrobial resistance continues to threaten global public health. Further hastening antimicrobial resistance is the lack of new antibiotics against...
The rising rate of antimicrobial resistance continues to threaten global public health. Further hastening antimicrobial resistance is the lack of new antibiotics against new targets. The bacterial enzyme, 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), is thought to play important roles in central metabolism, including processes required for pathogen adaptation to fluctuating host environments. Thus, impairing DXPS function represents a possible new antibacterial strategy. We previously investigated a DXPS-dependent metabolic adaptation as a potential target in uropathogenic (UPEC) associated with urinary tract infection (UTI), using the DXPS-selective inhibitor butyl acetylphosphonate (BAP). However, investigations of DXPS inhibitors have not been conducted. The goal of the present study is to advance DXPS inhibitors as probes and assess the potential of inhibiting DXPS as a strategy to prevent UTI . We show that BAP was well-tolerated at high doses in mice and displayed a favorable pharmacokinetic profile for studies in a mouse model of UTI. Further, an alkyl acetylphosphonate prodrug (homopropargyl acetylphosphonate, pro-hpAP) was significantly more potent against UPEC in urine culture and exhibited good exposure in the urinary tract after systemic dosing. Prophylactic treatment with either BAP or pro-hpAP led to a partial protective effect against UTI, with the prodrug displaying improved efficacy compared to BAP. Overall, our results highlight the potential for DXPS inhibitors as probes and establish preliminary evidence that inhibiting DXPS impairs UPEC colonization in a mouse model of UTI.IMPORTANCENew antibiotics against new targets are needed to prevent an antimicrobial resistance crisis. Unfortunately, antibiotic discovery has slowed, and many newly FDA-approved antibiotics do not inhibit new targets. Alkyl acetylphosphonates (alkyl APs), which inhibit the enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), represent a new possible class of compounds as there are no FDA-approved DXPS inhibitors. To our knowledge, this is the first study demonstrating the safety, pharmacokinetics, and efficacy of alkyl APs in a urinary tract infection mouse model.
Topics: Animals; Mice; Urinary Tract Infections; Anti-Bacterial Agents; Prodrugs; Anti-Infective Agents; Escherichia coli Infections; Uropathogenic Escherichia coli; Acetaldehyde; Pentosephosphates
PubMed: 38376151
DOI: 10.1128/spectrum.03896-23 -
A translation proofreader of archaeal origin imparts multi-aldehyde stress tolerance to land plants.ELife Feb 2024Aldehydes, being an integral part of carbon metabolism, energy generation, and signalling pathways, are ingrained in plant physiology. Land plants have developed...
Aldehydes, being an integral part of carbon metabolism, energy generation, and signalling pathways, are ingrained in plant physiology. Land plants have developed intricate metabolic pathways which involve production of reactive aldehydes and its detoxification to survive harsh terrestrial environments. Here, we show that physiologically produced aldehydes, i.e., formaldehyde and methylglyoxal in addition to acetaldehyde, generate adducts with aminoacyl-tRNAs, a substrate for protein synthesis. Plants are unique in possessing two distinct chiral proofreading systems, D-aminoacyl-tRNA deacylase1 (DTD1) and DTD2, of bacterial and archaeal origins, respectively. Extensive biochemical analysis revealed that only archaeal DTD2 can remove the stable D-aminoacyl adducts on tRNA thereby shielding archaea and plants from these system-generated aldehydes. Using as a model system, we have shown that the loss of DTD2 gene renders plants susceptible to these toxic aldehydes as they generate stable alkyl modification on D-aminoacyl-tRNAs, which are recycled only by DTD2. Bioinformatic analysis identifies the expansion of aldehyde metabolising repertoire in land plant ancestors which strongly correlates with the recruitment of archaeal DTD2. Finally, we demonstrate that the overexpression of DTD2 offers better protection against aldehydes than in wild type highlighting its role as a multi-aldehyde detoxifier that can be explored as a transgenic crop development strategy.
Topics: Aldehydes; Arabidopsis; RNA, Transfer, Amino Acyl; Bacteria; Archaea; RNA, Transfer
PubMed: 38372335
DOI: 10.7554/eLife.92827 -
Food Chemistry: X Mar 2024To better understand the effect of oxygen levels in the storage environment on peanut protein oxidation and explore the mechanism, the functional properties and the...
To better understand the effect of oxygen levels in the storage environment on peanut protein oxidation and explore the mechanism, the functional properties and the oxidation degree of peanut proteins extracted from peanuts under conventional storage (CS), nitrogen modified atmosphere storage (NS, hypoxic) and re-aeration storage (RS) were investigated. Metabolomics and proteomics were employed to analyze peanut's response to hypoxic/re-aeration storage environment. The results showed that NS retarded the decline of the functional properties and the oxidation of peanut proteins, while the process were accelerated after re-aeration. That was the result of the metabolic changes of peanuts under different storage environments. The omics results presented the decreased (NS)/increased (RS) levels of the antioxidant-related proteins acetaldehyde dehydrogenase and glutathione S-transferase, and the inhibition (NS)/activation (RS) of metabolic pathways such as the TCA cycle and the pentose phosphate pathway. This study provided a reference for the re-aeration storage of other agricultural products.
PubMed: 38370304
DOI: 10.1016/j.fochx.2024.101173 -
Chemical Science Feb 2024Patients with alcoholism and type 2 diabetes manifest altered metabolism, including elevated aldehyde levels and unusually low asparagine levels. We show that asparagine...
Patients with alcoholism and type 2 diabetes manifest altered metabolism, including elevated aldehyde levels and unusually low asparagine levels. We show that asparagine synthetase B (ASNS), the only human asparagine-forming enzyme, is inhibited by disease-relevant reactive aldehydes, including formaldehyde and acetaldehyde. Cellular studies show non-cytotoxic amounts of reactive aldehydes induce a decrease in asparagine levels. Biochemical analyses reveal inhibition results from reaction of the aldehydes with the catalytically important N-terminal cysteine of ASNS. The combined cellular and biochemical results suggest a possible mechanism underlying the low asparagine levels in alcoholism and diabetes. The results will stimulate research on the biological consequences of the reactions of aldehydes with nucleophilic residues.
PubMed: 38362406
DOI: 10.1039/d3sc06551k -
Communications Chemistry Feb 2024The transition from inorganic catalysis through minerals to organic catalysis by enzymes is a necessary step in the emergence of life. Our work is elucidating likely...
The transition from inorganic catalysis through minerals to organic catalysis by enzymes is a necessary step in the emergence of life. Our work is elucidating likely reactions at the earliest moments of Life, prior to the existence of enzymatic catalysis, by exploring essential intersections between nickel bioinorganic chemistry and pterin biochemistry. We used a prebiotically-inspired acetylene-containing volcanic hydrothermal experimental environment to shed light on the efficient formation of nickel-organo complexes. The simplest bis(dithiolene)nickel complex (CHS)Ni was identified by UV/Vis spectroscopy, mass spectrometry, nuclear magnetic resonance. Its temporal progression and possible function in this simulated early Earth atmosphere were investigated by isolating the main bis(dithiolene)nickel species from the primordial experimental setup. Using this approach, we uncovered a significant diversity of nickel-organo compositions by identifying 156 elemental annotations. The formation of acetaldehyde through the subsequent degradation of these organo-metal complexes is intriguing, as it is reminiscent of the ability of Pelobacter acetylenicus to hydrate acetylene to acetaldehyde via its bis(dithiolene)-containing enzyme acetylene hydratase. As our findings mechanistically characterize the role of nickel sulfide in catalyzing the formation of acetaldehyde, this fundamental pre-metabolic reaction could play the role of a primitive enzyme precursor of the enzymatic acetylene metabolism and further strengthen the role of acetylene in the molecular origin of life.
PubMed: 38361005
DOI: 10.1038/s42004-024-01119-0 -
Food Chemistry: X Mar 2024To attain the differences in the flavor profile of Douchi, the key aroma-active compounds of three types of Douchi were investigated. The "Sauce-like", "Smoky", "Nutty",...
To attain the differences in the flavor profile of Douchi, the key aroma-active compounds of three types of Douchi were investigated. The "Sauce-like", "Smoky", "Nutty", "Roast", "Caramel", and "Flower" of Douchi were favored by customers. Further, a total of 179 volatile compounds were identified using HS-SPME-GC-MS, and 29 aroma compounds were detected using GC-O-MS. Based on the quantification, 9, 13, and 10 compounds were regarded as aroma-active compounds in Yangjiang Douchi (YJ), Pingjiang Douchi (PJ), and Liuyang Douchi (LY), respectively. Moreover, the mixture of these aroma-active compounds successfully simulated the main aromas of PJ, LY, and YJ. And omission experiments confirmed that guaiacol was the key aroma compound for LY, benzene acetaldehyde, dimethyl trisulfide, and 2-acetyl pyrrole were important for YJ, benzene acetaldehyde and 3,5-diethyl-2-methyl pyrazine notably contributed to key aroma of PJ.
PubMed: 38357375
DOI: 10.1016/j.fochx.2024.101170 -
Foods (Basel, Switzerland) Jan 2024Pursh (Penthoraceae) is a traditional herb used in Miao medical systems that is also processed into foods (e.g., tea products) in China. Different processing methods...
Pursh (Penthoraceae) is a traditional herb used in Miao medical systems that is also processed into foods (e.g., tea products) in China. Different processing methods significantly affect the volatile compounds, phenolic constituents, and biological activities. This study aimed to produce green tea leaves (GTL), black tea leaves (BTL), and untreated leaves (UL) to investigate differences in their flavor substances, functional components, antioxidant activity, alcohol dehydrogenase (ADH) activity, and acetaldehyde dehydrogenase (ALDH) activity. The results showed that 63, 56, and 56 volatile compounds were detected in UL, GTL, and BTL, respectively, of which 43 volatile compounds were identified as differential metabolites among them. The total phenolic content (97.13-179.34 mg GAE/g DW), flavonoid content (40.07-71.93 mg RE/g DW), and proanthocyanidin content (54.13-65.91 mg CE/g DW) exhibited similar trends, decreasing in the order of UL > BTL > GTL. Fourteen phenolic compounds were determined, of which gallic acid, (-)-epicatechin, and pinocembrin 7--glucoside showed a sharp decrease in content from UL to BTL, while the content of pinocembrin 7--(3″--galloy-4″, 6″-hexahydroxydiphenoyl)-glucoside and pinocembrin significantly increased. GTL showed better DPPH/ABTS scavenging ability and ferric-reducing ability than UL. The ADH and ALDH activities decreased in the order of GTL > UL > BTL. Therefore, tea products made with leaves contained an abundance of functional compounds and showed satisfactory antioxidant and hepatoprotective activities, which are recommended for daily consumption.
PubMed: 38338534
DOI: 10.3390/foods13030399 -
Journal of Dairy Science Feb 2024Synergistic fermentation of milk by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus is one of the key factors that determines the quality of...
Synergistic fermentation of milk by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus is one of the key factors that determines the quality of yogurt. In this study, the mechanism whereby yogurt flavor compounds are produced by mixture of S. thermophilus SIT-20.S and L. delbrueckii ssp. bulgaricus SIT-17.B were investigated by examining these strains' flavor production, growth, and gene transcription. The results showed that yogurt produced by a 10:1 mixture of the aforementioned strains had the highest abundance of acetoin, whereas yogurt produced by a 1:1 mixture had the highest abundance of diacetyl and acetaldehyde. In addition, the growth of S. thermophilus SIT-20.S was enhanced in the 10:1 mixture. Transcriptomic analysis revealed differentially expressed genes in the flavor-compound-related pathways of S. thermophilus SIT-20.S and L. delbrueckii ssp. bulgaricus SIT-17.B in yogurts produced by 10:1 and 1:1 mixture compared with those produced by either strain alone. Mixed fermentations regulated the expression of genes related to glycolysis, resulting in an increase of pyruvate, which is an important precursor for diacetyl and acetoin synthesis. The gene encoding the acetoin reductase (SIT-20S_orf01454) was decreased in S. thermophilus SIT-20.S, which ensured the accumulation of acetoin. Besides, gene encoding the acetaldehyde dehydrogenase (SIT-20S_orf00949) was upregulated in S. thermophilus SIT-20.S, and the expression of alcohol dehydrogenase (SIT-20S_orf01479; SIT-17B_orf00943) was downregulated in both strains, maintaining the abundance of acetaldehyde. In addition, the gene encoding the NADH oxidase (SIT-17B_orf00860) in L. delbrueckii ssp. bulgaricus SIT-17.B were upregulated, which promoted the accumulation of diacetyl and acetoin. In conclusion, we characterized the mechanism by which S. thermophilus and L. delbrueckii ssp. bulgaricus synergistically generated yogurt flavor compounds during their production of yogurt and highlighted the importance of appropriate proportions of fermentation starters for improving the flavor of yogurts.
PubMed: 38331185
DOI: 10.3168/jds.2023-24328 -
ACS Omega Jan 2024For polyethylene terephthalate (PET) bottles, a material used for food packaging, light transmission and mechanical performance, particularly environmental stress...
For polyethylene terephthalate (PET) bottles, a material used for food packaging, light transmission and mechanical performance, particularly environmental stress cracking (ESC), are essential characteristics. For this purpose, following extrusion of PET/CaO granules, preforms were manufactured using the injection technique, and bottles were produced by a stretch-blow-molding process. With incorporation of calcium oxide (CaO), light transmittance increased by around 25%, and ESC went from 0.3 to 11 min. In addition, whereas acetaldehyde (AA) and carboxylic acid (COOH) decomposition values rose with increasing CaO content, diethylene glycol and isophthalic acid values did not significantly change. Moreover, the maximum crystallization temperature and crystallinity both exhibited an upward trend with the CaO content.
PubMed: 38284055
DOI: 10.1021/acsomega.3c07193