Impact of ozone treatment on dissolved organic matter in land-based recirculating aquaculture systems studied by Fourier transform ion cyclotron resonance mass spectrometry

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Natural complex mixtures unequivocally defined in formulae difference space

Direct comparison of high-resolution mass spectrometry (HRMS) data acquired with different instrumentation or parameters remains difficult as the derived lists of molecular species via HRMS, even for the same sample, appear distinct. This inconsistency is the result of inherent inaccuracies caused by instrumental limitations and sample conditions. We propose a method that classifies HRMS data based on the differences in the number of elements between each pair of molecular formulae within the formulae list to preserve the essence of the given sample. The novel metric, Formulae Difference Chains Expected Length (FDCEL), allowed for comparing and classifying samples measured by different instruments. FDCEL metric was implemented for both spectrum quality control and for examination of samples of various nature. We also demonstrate a web application and a prototype for a uniform database for HRMS data serving as a benchmark for future biogeochemical applications

Directed Synthesis of Humic and Fulvic Derivatives with Enhanced Antioxidant Properties

Redox moieties, which are present in the molecular backbone of humic substances (HS), govern their antioxidant properties. We hypothesized that a directed modification of the humic backbone via incorporation of redox moieties with known redox properties might provide an efficient tool for tuning up antioxidant properties of HS. In this work, hydroquinonoid and hydronaphthoquinonoid centres were used, which possess very different redox characteristics. They were incorporated into the structure of coal (leonardite) humic acids CHA) and peat fulvic acids (PFA). For this goal, an oxidative copolymerization of phenols was used. The latter was induced via oxidation of hydroquinones and hydroxynapjtaquinones with a use of Fenton’s reagent. The structure of the obtained products was characterized using NMR and FTIR spectroscopy. H/D labelling coupled to FT ICR mass spectrometry analysis was applied for identification of the reaction products as a tool for surmising on reaction mechanism. It was shown that covalent -C-C- bond were formed between the incorporated redox centers and aromatic core of HS. The parent humic acids and their naphthoquinonoid derivatives have demonstrated high accepting capacity. At the same time, fulvic acids and their hydroquinonoid derivatives have possessed both high donor and high antioxidant capacities. The kinetic studies have demonstrated that both humic acids and their derivatives showed much slower kinetics of antioxidant reactions as compared to fulvic acids. The obtained results show, firstly, substantial difference in redox and antioxidant properties of the humic and fulvic acids, and, secondly, they can serve as an experimental evidence that directed chemical modification of humic substances can be used to tune and control antioxidant properties of natural HS

Hepatoprotective Activity of Lignin-Derived Polyphenols Dereplicated Using High-Resolution Mass Spectrometry, In Vivo Experiments, and Deep Learning

Chronic liver diseases affect more than 1 billion people worldwide and represent one of the main public health issues. Nonalcoholic fatty liver disease (NAFLD) accounts for the majority of mortal cases, while there is no currently approved therapeutics for its treatment. One of the prospective approaches to NAFLD therapy is to use a mixture of natural compounds. They showed effectiveness in alleviating NAFLD-related conditions including steatosis, fibrosis, etc. However, understanding the mechanism of action of such mixtures is important for their rational application. In this work, we propose a new dereplication workflow for deciphering the mechanism of action of the lignin-derived natural compound mixture. The workflow combines the analysis of molecular components with high-resolution mass spectrometry, selective chemical tagging and deuterium labeling, liver tissue penetration examination, assessment of biological activity in vitro, and computational chemistry tools used to generate putative structural candidates. Molecular docking was used to propose the potential mechanism of action of these structures, which was assessed by a proteomic experiment

Effects of Isoflavone-Rich NADES Extract of Pueraria lobata Roots and Astaxanthin-Rich Phaffia rhodozyma Extract on Prostate Carcinogenesis in Rats

Prostate cancer (PCa) is one of the most common male malignancies worldwide. In the current study, we evaluated the effects of a natural deep eutectic solvent (NADES) extract of Pueraria lobata roots rich in isoflavones (ISF) and Phaffia rhodozyma extract rich in astaxanthin (ASX) on an N-methyl-N-nitrosourea plus testosterone PCa model in rats. ISF consisted of puerarin, daidzein, genistein, formononetin and other polyphenols, while ASX contained lipids and unsaturated species in addition to astaxanthin. Extracts were administered through a whole promotion period in daily doses shown by our group to successfully inhibit benign prostate hyperplasia (BPH) development — 200 mg/kg for ISF and 25 mg/kg for ASX. Though a similar effect was found for BPH processes accompanying PCa induction, the incidence of PCa in animals treated with placebo, ISF and ASX was 37%, 37% and 41%, respectively, showing no chemopreventive activity of ISF and ASX. PCa development was associated with a decrease in the Ca/Mg ratio in serum and an increase in prostate tissue. Treatment with both extracts produced a normalization effect on Ca balance in serum, which, combined with a decrease in the prostatic index, suggests some positive health effects of ISF and ASX

Dissection of the Deep-blue Autofluorescence Changes Accompanying Amyloid Fibrillation

Pathogenesis of numerous diseases is associated with the formation of amyloid fibrils. Extrinsic fluorescent dyes, including Thioflavin T (ThT), are used to follow the fibrillation kinetics. It has recently been reported that the so-called deep-blue autofluorescence (dbAF) is changing during the aggregation process. However, the origin of dbAF and the reasons for its change remain debatable. Here, the kinetics of fibril formation in model proteins were comprehensively analyzed using fluorescence lifetime and intensity of ThT, intrinsic fluorescence of proteinaceous fluorophores, and dbAF. For all systems, intensity enhancement of the dbAF band with similar spectral parameters (∼350 nm excitation; ∼450 nm emission) was observed. Although the time course of ThT lifetime (indicative of protofibrils formation) coincided with that of tyrosine residues in insulin, and the kinetic changes in the ThT fluorescence intensity (reflecting formation of mature fibrils) coincided with changes in ThT absorption spectrum, the dbAF band started to increase from the beginning of the incubation process without a lag-phase. Our mass-spectrometry data and model experiments suggested that dbAF could be at least partially related to oxidation of amino acids. This study scrutinizes the dbAF features in the context of the existing hypotheses about the origin of this spectral band