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Li F, Karongo R, Mavridou D, Horak J, Sievers-Engler A, Lämmerhofer M. Automated sample preparation with 6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate and iodoacetamide derivatization reagents for enantioselective liquid chromatography tandem mass spectrometry amino acid analysis. J Chromatogr A 2023; 1708:464349. [PMID: 37696129 DOI: 10.1016/j.chroma.2023.464349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023]
Abstract
Enantioselective amino acid analysis is gaining increasing importance in pharmaceutical, biomedical and food sciences. While there are many methods available for enantiomer separation of amino acids, the simultaneous analysis of all chiral proteinogenic amino acids by a single method with one column and a single condition is still challenging. Herein, we report an enantioselective high-performance liquid chromatography-tandem mass spectrometry (LC-MS) assay using Chiralpak QN-AX as chiral column. With 6-aminoquinolyl-N-hydrosysuccinimidyl carbamate (AQC) as derivatization reagent, efficient enantioselective separation of D- and L-amino acids using HPLC has become possible. Thiol-containing amino acids like Cys are alkylated prior to AQC-labelling. A protocol for automated sample preparation including both derivatization step and calibrator preparation is presented. For compensating matrix effects, u-13C15N-labelled internal standards (IS) were employed. The method was validated and applied to the enantioselective analysis of amino acids in a bacterial fermentation broth.
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Affiliation(s)
- Feiyang Li
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Ryan Karongo
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany; Invite GmbH, Formulation Technology, 42096 Wuppertal, Germany; Bayer AG, Research & Development, Pharmaceuticals, Analytical Development API, 42096 Wuppertal, Germany
| | - Despoina Mavridou
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Jeannie Horak
- Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University Munich Medical Center, Lindwurmstraße 4, 80337 Munich, Germany
| | - Adrian Sievers-Engler
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Michael Lämmerhofer
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany.
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Howard S, Furniss C, Bonini D, Amin H, Paracuellos-Torrecilla P, Costa T, Mavridou D, Filloux A. The Type VI Secretion System of Pseudomonas aeruginosa: a gun loaded with antimicrobial bullets. Access Microbiol 2020. [DOI: 10.1099/acmi.ac2020.po0620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can cause severe respiratory infections in people who are immunocompromised. P. aeruginosa possesses the Type VI Secretion System (T6SS), a bacterial weapon that injects effectors into neighbouring prokaryotes and eukaryotes. The T6SS is crucial for bacterial warfare, allowing P. aeruginosa to kill its competitors, which promotes its dominance in mixed microbial environments. P. aeruginosa has three T6SSs, H1/2/3-T6SS, these are structural homologs but deliver unique effectors. Effectors are delivered via the secreted component, a Hcp tube topped with a VgrG and PAAR spike. Only the first three identified effectors are delivered by Hcp1. Since then, there has been a bias in identification of VgrG or PAAR delivered effectors, mostly as these are encoded next to the spike proteins. Some P. aeruginosa effectors not only kill bacteria but have a dual role in pathogenesis. Our aim was to identify a comprehensive set of Hcp-delivered effectors for all three systems. Using Hcp1/2/3, systematic pull-down screens were performed to identify novel interaction partners. After confirming interaction, antibacterial toxicity was evaluated, identifying new Hcp delivered T6SS effectors for Hcp2 and Hcp3, which are toxic in the bacterial cytoplasm. These new anti-bacterial effectors may kill bacteria in novel ways, which could lead to novel antibiotics. Additionally, a toxin fusion proved too large for secretion and blocked the T6SS, revealing a Hcp-delivered effector size limit. Future work will focus on fully characterising these new toxins, as well as to look into the potential eukaryotic role of other interaction partners.
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Affiliation(s)
| | | | - Dora Bonini
- University of Bristol,Bristol,United Kingdom
| | - Himani Amin
- Imperial College London,London,United Kingdom
| | | | - Tiago Costa
- Imperial College London,London,United Kingdom
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Mavridou D, Webb B, Seomkin L, King C. O596 Massive ascites associated with endometriosis in a patient from Ghana. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)60969-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
Respiratory bronchiolitis associated interstitial lung disease (RB-ILD) is a recently described clinicopathological entity that occurs almost exclusively in current heavy cigarette smokers. Few cases have been reported in the literature and no studies have been carried out on the effect of treatment, which currently consists of smoking cessation with or without corticosteroids. We report the first case of an acute presentation of histologically proven RB-ILD in a young cigarette smoker whose diagnosis and management proved to be difficult. Smoking cessation alone was found to be inadequate so management was combined with corticosteroid therapy.
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Affiliation(s)
- D Mavridou
- Thoracic Department, Royal Bournemouth Hospital, Castle Lane East, Bournemouth BH7 7DW, UK.
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Van der Krieken WM, Breteler H, Visser MH, Mavridou D. The role of the conversion of IBA into IAA on root regeneration in apple: introduction of a test system. Plant Cell Rep 1993; 12:203-6. [PMID: 24197020 DOI: 10.1007/bf00237054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/1992] [Revised: 10/16/1992] [Indexed: 05/25/2023]
Abstract
A test system for root regeneration was developed that consists of stem slices of apple shoots (ca. 0.5 mm thick; fresh weight ca. 1 mg). Roots regenerated synchronously without intervening callus formation and without interference with compounds originating from other parts of the plant. Supply of indolebutyric acid (IBA) or indoleacetic acid (IAA) induced maximally an average of 8 or 4.5 roots per slice, respectively. After uptake of IBA, a high degree of conjugation resulted in a recovery of 2.5% as internal free IBA (ca. 2 times the medium concentration). Due to conversion of absorbed IBA into IAA a fraction of 0.4% was recovered as (physiologically active) free IAA. After incubation on medium with IAA, 0.5% of the absorbed hormone was recovered in the free acid form. No conversion of IAA into IBA was observed. Equimolar contents of internal free IAA after incubation on IBA or IAA resulted for IBA in a higher number of roots than for IAA. This means that IBA may also act via internal free IBA or may synergistically modify the action or endogenous synthesis of IAA.
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Affiliation(s)
- W M Van der Krieken
- Department of Biochemistry and Cell Physiology, Centre for Agrobiological Research, P.O. Box 14, NL-6700, AA Wageningen, The Netherlands
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