title: Solid phase extraction and metabolic profiling of exudates from living copepods.
abstract: Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds that constitute a specific chemical pattern either qualitatively or quantitatively indicating copepod presence. The majority of the compounds were present in both female and male exudates, but nine compounds were mainly or exclusively present in female exudates and hence potential pheromone candidates. Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms.
authors.affiliation: Department of Marine Sciences, University of Gothenburg,Göteborg, Sweden; Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen, Denmark.
authors.forename: Erik
authors.initials: E
authors.lastname: Selander
authors.affiliation: Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark , Copenhagen , Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Heuschele
authors.affiliation: Department of Marine Sciences, University of Gothenburg, Göteborg , Sweden.
authors.forename: Göran M
authors.initials: GM
authors.lastname: Nylund
authors.affiliation: Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University , Jena , Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Pohnert
authors.affiliation: Department of Marine Sciences, University of Gothenburg, Göteborg , Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Pavia
authors.affiliation: Department of Biosciences, University of Oslo , Oslo , Norway.
authors.forename: Oda
authors.initials: O
authors.lastname: Bjærke
authors.affiliation: School of Biology, Georgia Institute of Technology , Atlanta, GA , USA.
authors.forename: Larisa A
authors.initials: LA
authors.lastname: Pender-Healy
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg , Göteborg , Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Tiselius
authors.affiliation: Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark , Copenhagen , Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kiørboe
keywords: Copepod exudate; Exometabolome; Infochemicals; Metabolomics; Temora longicornis