TY - JOUR A1 - Müller, Marik A1 - Nedielkov, Ruslan A1 - Arndt, Katja M. T1 - Strategies for Enzymatic Inactivation of the Veterinary Antibiotic Florfenicol JF - Antibiotics N2 - Large quantities of the antibiotic florfenicol are used in animal farming and aquaculture, contaminating the ecosystem with antibiotic residues and promoting antimicrobial resistance, ultimately leading to untreatable multidrug-resistant pathogens. Florfenicol-resistant bacteria often activate export mechanisms that result in resistance to various structurally unrelated antibiotics. We devised novel strategies for the enzymatic inactivation of florfenicol in different media, such as saltwater or milk. Using a combinatorial approach and selection, we optimized a hydrolase (EstDL136) for florfenicol cleavage. Reaction kinetics were followed by time-resolved NMR spectroscopy. Importantly, the hydrolase remained active in different media, such as saltwater or cow milk. Various environmentally-friendly application strategies for florfenicol inactivation were developed using the optimized hydrolase. As a potential filter device for cost-effective treatment of waste milk or aquacultural wastewater, the hydrolase was immobilized on Ni-NTA agarose or silica as carrier materials. In two further application examples, the hydrolase was used as cell extract or encapsulated with a semi-permeable membrane. This facilitated, for example, florfenicol inactivation in whole milk, which can help to treat waste milk from medicated cows, to be fed to calves without the risk of inducing antibiotic resistance. Enzymatic inactivation of antibiotics, in general, enables therapeutic intervention without promoting antibiotic resistance. KW - aquaculture KW - antibiotic inactivation KW - enzyme optimization KW - enzymatic inactivation KW - florfenicol KW - immobilization KW - industrial farming Y1 - 2022 U6 - https://doi.org/10.3390/antibiotics11040443 SN - 2079-6382 VL - 11 IS - 4 SP - 1 EP - 18 PB - MDPI CY - Basel, Schweiz ER - TY - GEN A1 - Müller, Marik A1 - Nedielkov, Ruslan A1 - Arndt, Katja M. T1 - Strategies for Enzymatic Inactivation of the Veterinary Antibiotic Florfenicol T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Large quantities of the antibiotic florfenicol are used in animal farming and aquaculture, contaminating the ecosystem with antibiotic residues and promoting antimicrobial resistance, ultimately leading to untreatable multidrug-resistant pathogens. Florfenicol-resistant bacteria often activate export mechanisms that result in resistance to various structurally unrelated antibiotics. We devised novel strategies for the enzymatic inactivation of florfenicol in different media, such as saltwater or milk. Using a combinatorial approach and selection, we optimized a hydrolase (EstDL136) for florfenicol cleavage. Reaction kinetics were followed by time-resolved NMR spectroscopy. Importantly, the hydrolase remained active in different media, such as saltwater or cow milk. Various environmentally-friendly application strategies for florfenicol inactivation were developed using the optimized hydrolase. As a potential filter device for cost-effective treatment of waste milk or aquacultural wastewater, the hydrolase was immobilized on Ni-NTA agarose or silica as carrier materials. In two further application examples, the hydrolase was used as cell extract or encapsulated with a semi-permeable membrane. This facilitated, for example, florfenicol inactivation in whole milk, which can help to treat waste milk from medicated cows, to be fed to calves without the risk of inducing antibiotic resistance. Enzymatic inactivation of antibiotics, in general, enables therapeutic intervention without promoting antibiotic resistance. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1266 KW - aquaculture KW - antibiotic inactivation KW - enzyme optimization KW - enzymatic inactivation KW - florfenicol KW - immobilization KW - industrial farming Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-561621 SN - 1866-8372 SP - 1 EP - 18 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Vorburger, Thomas A1 - Nedielkov, Ruslan A1 - Brosig, Alexander A1 - Bok, Eva A1 - Schunke, Emina A1 - Steffen, Wojtek A1 - Mayer, Sonja A1 - Goetz, Friedrich A1 - Möller, Heiko Michael A1 - Steuber, Julia T1 - Role of the Na+-translocating NADH:quinone oxidoreductase in voltage generation and Na+ extrusion in Vibrio cholerae JF - Biochimica et biophysica acta : Bioenergetics N2 - For Vibrio cholerae, the coordinated import and export of Na+ is crucial for adaptation to habitats with different osmolarities. We investigated the Na+-extruding branch of the sodium cycle in this human pathogen by in vivo Na-23-NMR spectroscopy. The Na+ extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). In a V. cholerae deletion mutant devoid of the Na+-NQR encoding genes (nqrA-F), rates of respiratory Na+ extrusion were decreased by a factor of four, but the cytoplasmic Na+ concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (Delta psi, inside negative) and did not grow under hypoosmotic conditions at pH 8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na+/H+ antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na+ concentrations, the Na+-NQR is crucial for generation of a transmembrane voltage to drive the import of H+ by electrogenic Na+/H+ antiporters. Our study provides the basis to understand the role of the Na+-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na+ pump for respiration. (C) 2015 Elsevier B.V. All rights reserved. KW - Nuclear magnetic resonance (NMR) KW - Sodium transport KW - Vibrio cholerae KW - Respiration KW - Na+ homeostasis KW - Hypoosmotic stress Y1 - 2016 U6 - https://doi.org/10.1016/j.bbabio.2015.12.010 SN - 0005-2728 SN - 0006-3002 VL - 1857 SP - 473 EP - 482 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Ramadan, Shahenda A1 - Guerrero, Paula A1 - Nedielkov, Ruslan A1 - Klishin, Nikolai A1 - Dimova, Rumiana A1 - Silva, Daniel V. A1 - Möller, Heiko T1 - Building a mimetic system for unraveling protein-protein interactions on membranes T2 - European biophysics journal : with biophysics letters ; an international journal of biophysics Y1 - 2021 U6 - https://doi.org/10.1007/s00249-021-01558-w SN - 0175-7571 SN - 1432-1017 VL - 50 IS - SUPPL 1 SP - S153 EP - S153 PB - Springer CY - Berlin ; Heidelberg ; New York ER -