title: Toxicity evaluation of selected ammonium-based ionic liquid forms with MCPP and dicamba moieties on Pseudomonas putida.
abstract: Combination of the hydrophilic herbicidal anion with hydrophobic, antimicrobial ammonium cation allows to obtain compounds in ionic liquid form with better properties then conventional herbicides. Both cation and anion can be modified by selection of herbicide and the length of alkyl chains in cation structure. However the knowledge of their potential toxic effects are still limited. Furthermore, the relation between hydrophobicity associated with the length of alkyl chains and toxicity for ionic liquids has not been thoroughly studied. Therefore we investigated toxic effects of herbicidal ionic liquid forms on growth inhibition, given as EC50,of the common soil bacterium Pseudomonas putida. We thereby concentrated on quaternary ammonium salts. Analyzed compounds were composed of dicamba or MCPP moieties and cation with various alkyl chain lengths (n = 6,8,10) We compared them with commercial herbicides, and ammonium-based ionic liquids with neutral anion (Br-). In addition, cis-trans isomerisation of unsaturated membrane fatty acids in Pseudomonas putida was applied as the proxy for toxicity and membrane activity. We showed that toxicity increased with the length of alkyl chains. However, this correlation is only valid for six and eight carbon atom in alkyl chains, where for n = 10 the EC50values rise by one order of magnitude. In our studies, the herbicidal ionic liquids [C10,C10,C1,C1N][MCPP] and [C10,C10,C1,C1N][dicamba] showed the lowest toxicity among analyzed quaternary ammonium salts and comparable toxicity with corresponding herbicides. No clear increase in toxicity could be followed by changing the anion moieties for ammonium-based ionic liquid forms.
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, 04318 Leipzig, Germany; Faculty of Chemical Technology, Poznan University of Technology, ul. Berdychowo 4, 60-965 Poznan, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Piotrowska
authors.affiliation: Faculty of Chemical Technology, Poznan University of Technology, ul. Berdychowo 4, 60-965 Poznan, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Syguda
authors.affiliation: Faculty of Chemical Technology, Poznan University of Technology, ul. Berdychowo 4, 60-965 Poznan, Poland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Wyrwas
authors.affiliation: Faculty of Chemical Technology, Poznan University of Technology, ul. Berdychowo 4, 60-965 Poznan, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Chrzanowski
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, 04318 Leipzig, Germany. Electronic address: hermann.heipieper@ufz.de.
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Heipieper
mesh_terms: D003996:Dicamba / Q000633:toxicity*; D006540:Herbicides / Q000633:toxicity*; D052578:Ionic Liquids / Q000633:toxicity*; D016958:Pseudomonas putida / Q000187:drug effects* / Q000254:growth & development; D000644:Quaternary Ammonium Compounds / Q000633:toxicity*
chemical_list: D006540:Herbicides; D052578:Ionic Liquids; D000644:Quaternary Ammonium Compounds; D003996:Dicamba
keywords: Cis-trans isomerisation; EC(50); Fatty acid methyl esters (FAME); Herbicidal ionic liquids; Pseudomonas putida; Quaternary ammonium ionic liquids; Toxicity