Browsing by Subject "CHROMATOGRAPHY"

Sort by: Order: Results:

Now showing items 1-6 of 6
  • Sanwald, Corinna; Robciuc, Alexandra; Ruokonen, Suvi-Katriina; Wiedmer, Susanne K.; Lammerhofer, Michael (2019)
    This work presents the development and validation of a quantitative HILIC UHPLC-ESI-QTOF-MS/MS method for amino acids combined with untargeted metabolic profiling of human corneal epithelial (HCE) cells after treatment with ionic liquids. The work included a preliminary metabotoxicity screening of 14 different ionic liquids, of which 9 carefully selected ionic liquids were chosen for a metabolomics study. This study is focused on the correlation between the toxicity of the ionic liquids and their metabolic profiles. The method development included the comparison of different MS/MS acquisition modes. A sequential window acquisition of all theoretical fragment ion mass spectra (SWATH) method with variable Q1 window widths and narrow Q1 target windows of 5 Da for most of the amino acids was selected as the optimal acquisition mode. Due to the absence of a true blank matrix, C-13,N-15-isotopically labelled amino acids were utilized as surrogate calibrants, instead of proteinogenic amino acids. Partial least squares (PLS) analysis of the median effective concentrations (EC50) of 9 selected ionic liquids showed a correlation with their metabolic profile measured by the untargeted screening.
  • Verni, Michela; Pontonio, Erica; Krona, Annika; Jacob, Sera; Pinto, Daniela; Verardo, Vito; Díaz-de-Cerio, Elixabet; Coda, Rossana; Rizzello, Carlo (2020)
    Brewers' spent grain (BSG) is the major by-product of the brewing industry which remain largely unutilized despite its nutritional quality. In this study, the effects of fermentation on BSG antioxidant potential were analyzed. A biotechnological protocol including the use of xylanase followed by fermentation withLactiplantibacillus plantarum (Lactobacillus plantarum)PU1, PRO17, and H46 was used. Bioprocessed BSG exhibited enhanced antioxidant potential, characterized by high radical scavenging activity, long-term inhibition of linoleic acid oxidation and protective effect toward oxidative stress on human keratinocytes NCTC 2544. Immunolabelling and confocal laser microscopy showed that xylanase caused an extensive cell wall arabinoxylan disruption, contributing to the release of bound phenols molecules, thus available to further conversion through lactic acid bacteria metabolism. To clarify the role of fermentation on the antioxidant BSG potential, phenols were selectively extracted and characterized through HPLC-MS techniques. Novel antioxidant peptides were purified and identified in the most active bioprocessed BSG.
  • Multia, Evgen; Tear, Crystal Jing Ying; Palviainen, Mari; Siljander, Pia R-M; Riekkola, Marja-Liisa (2019)
    A new, fast and selective immunoaffinity chromatographic method including a methacrylate-based convective interaction media (CIM (R)) disk monolithic column, immobilized with anti-human CD61 antibody, was developed for the isolation of CD61-containing platelet-derived extracellular vesicles (EVs) from plasma. The isolated EVs were detected and size characterized by asymmetrical flow field-flow fractionation (AsFlFFF) with multi-angle light-scattering (MALS) and dynamic light-scattering (DLS) detection, and further confirmed by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The mean size of platelet-derived EV isolates from the anti-CD61 CIM (R) disk monolithic column were 174 nm (SD 60 nm) based on the NTA results. These results indicated a successful isolation of platelet-derived EVs, which was confirmed by Western blotting the isolates against the EV-specific markers CD9 and TSG101 together with transmission electron microscopy. Additional elucidation of MALS and DLS data provided detailed information of the size distribution of the isolated fractions, confirming the successful isolation of also small platelet-derived EVs ranging from 30 to 130 nm based on the hydrodynamic radii. The isolation procedure took only 19 min and the time can be even further decreased by increasing the flow rate. The same immunoaffinity chromatographic procedure, following AsFlFFF allowed also the isolation and characterization of platelet-derived EVs from plasma in under 60 min. Since it is possible to regenerate the anti-CD61 disk for multiple uses, the methodology developed in this study provides a viable substitution and addition to the conventional EV isolation procedures. (C) 2019 Elsevier B.V. All rights reserved.
  • Liangsupree, Thanaporn; Multia, Evgen; Riekkola, Marja-Liisa (2021)
    Extracellular vesicles (EVs) are heterogenous membrane-bound vesicles released from various origins. EVs play a crucial role in cellular communication and mediate several physiological and pathological processes, highlighting their potential therapeutic and diagnostic applications. Due to the rapid increase in interests and needs to elucidate EV properties and functions, numerous isolation and separation approaches for EVs have been developed to overcome limitations of conventional techniques, such as ultracentrifugation. This review focuses on recently emerging and modern EV isolation and separation techniques, including size-, charge-, and affinity-based techniques while excluding ultracentrifugation and precipitation-based techniques due to their multiple limitations. The advantages and drawbacks of each technique are discussed together with insights into their applications. Emerging approaches all share similar features in terms of being time-effective, easy-to-operate, and capable of providing EVs with suitable and desirable purity and integrity for applications of interest. Combination and hyphenation of techniques have been used for EV isolation and separation to yield EVs with the best quality. The most recent development using an automated on-line system including selective affinity-based trapping unit and asymmetrical flow field-flow fractionation allows reliable isolation and fractionation of EV subpopulations from human plasma. (C) 2020 The Author(s). Published by Elsevier B.V.
  • Matthew Omoruyi, Iyekhoetin; Hokkanen, Mirja; Pohjanvirta, Raimo (2020)
    Commercially processed meat and fish products are common sources of human exposure to chemical food mutagens. In this study, we investigated the mutagenic potential of 20 different commercially processed meat and fish products (7 product types with 2-3 lots of each), along with the presence of four principal polycyclic aromatic hydrocarbons (PAHs) (benzo[a]pyrene [BaP], benzo[b]fluoranthene [BbF], benzo[a]anthracene [BaA] and chrysene [CHR]) in them. Sample extraction was carried out by an accelerated solvent extraction method, while the concentrations of the 4 PAHs were determined by gas chromatography-tandem mass spectrometry (GC-MS/MS). The mutagenic potential of food extracts was assessed by the standard plate incorporation assay (Ames test) using two strains ofSalmonellatyphimurium (TA 100 and TA 98) both in the presence and the absence of metabolic activation (S9-mix). The results show that in the majority of food items investigated, PAH levels were below the limit of quantification (0.78 mu g/kg), except for smoked fish (0.8-15 mu g/kg for the 3 lots), one batch of which even exceeded the maximum limits for both the sum of the 4 PAHs (44 mu g/kg vs. 30 mu g/kg) and BaP (8.2 mu g/kg vs. 5.0 mu g/kg). Furthermore, all three batches of smoked fish were also found to be mutagenic on both strains ofSalmonella, both in the presence and the absence of metabolic activation. Overall, the data from both assays were in a fairly good agreement with one another, suggesting that PAHs are major contributors to mutagenicity of processed food products and the set maximum levels for PAHs are usually protective against food mutagenicity, although food samples harboring PAHs at levels approaching the maximum limits may exhibit mutagenic potential. Since the number of samples investigated was relatively small, further studies are warranted to verify the conclusions.
  • Mäkelä, Noora; Sontag-Strohm, Tuula; Schiehser, Sonja; Potthast, Antje; Maaheimo, Hannu; Maina, Ndegwa H. (2017)
    Oxidation of cereal beta-glucans may affect their stability in food products. Generally, polysaccharides oxidise via different pathways leading to chain cleavage or formation of oxidised groups within the polymer chain. In this study, oxidation pathways of oat and barley beta-glucans were assessed with different concentrations of hydrogen peroxide (H2O2) or ascorbic acid (Asc) with ferrous iron (Fe2+) as a catalyst. Degradation of beta-glucans was evaluated using high performance size exclusion chromatography and formation of carbonyl groups using carbazole-9-carbonyloxyamine labelling. Furthermore, oxidative degradation of glucosyl residues was studied. Based on the results, the oxidation with Asc mainly resulted in glycosidic bond cleavage. With H2O2, both glycosidic bond cleavage and formation of carbonyl groups within the beta-glucan chain was found. Moreover, H2O2 oxidation led to production of formic acid, which was proposed to result from Ruff degradation where oxidised glucose (gluconic acid) is decarboxylated to form arabinose. (C) 2016 Elsevier Ltd. All rights reserved.