@article{GrzesiukSpijkermanLachmannetal.2018,
  author    = {Grzesiuk, Malgorzata and Spijkerman, Elly and Lachmann, Sabrina C. and Wacker, Alexander},
  title     = {Environmental concentrations of pharmaceuticals directly affect phytoplankton and effects propagate through trophic interactions},
  series = {Ecotoxicology and Environmental Safety},
  volume    = {156},
  journal   = {Ecotoxicology and Environmental Safety},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0147-6513},
  doi       = {10.1016/j.ecoenv.2018.03.019},
  pages     = {271 -- 278},
  year      = {2018},
  abstract  = {Pharmaceuticals are found in freshwater ecosystems where even low concentrations in the range of ng L-1 may affect aquatic organisms. In the current study, we investigated the effects of chronic exposure to three pharmaceuticals on two microalgae, a potential modulation of the effects by additional inorganic phosphorus (Pi) limitation, and a potential propagation of the pharmaceuticals' effect across a trophic interaction. The latter considers that pharmaceuticals are bioaccumulated by algae, potentially metabolized into more (or less) toxic derivates and consequently consumed by zooplankton. We cultured Acutodesmus obliquus and Nannochloropsis limnetica in Pi-replete and Pi-limited medium contaminated with one of three commonly human used pharmaceuticals: fluoxetine, ibuprofen, and propranolol. Secondly, we tested to what extent first level consumers (Daphnia magna) were affected when fed with pharmaceutical-grown algae. Chronic exposure, covering 30 generations, led to (i) decreased cell numbers of A. obliquus in the presence of fluoxetine (under Pi-replete conditions) (ii) increased carotenoid to chlorophyll ratios in N. limnetica (under Pi-limited conditions), and (iii) increased photosynthetic yields in A. obliquus (in both Pi-conditions). In addition, ibuprofen affected both algae and their consumer: Feeding ibuprofen-contaminated algae to Pi-stressed D. magna improved their survival. We demonstrate, that even very low concentrations of pharmaceuticals present in freshwater ecosystems can significantly affect aquatic organisms when chronically exposed. Our study indicates that pharmaceutical effects can cross trophic levels and travel up the food chain.},
  language  = {en}
}
@article{SpijkermanLukasWacker2017,
  author    = {Spijkerman, Elly and Lukas, Marcus and Wacker, Alexander},
  title     = {Ecophysiological strategies for growth under varying light and organic carbon supply in two species of green microalgae differing in their motility},
  series = {Phytochemistry : an international journal of plant biochemistry},
  volume    = {144},
  journal   = {Phytochemistry : an international journal of plant biochemistry},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0031-9422},
  doi       = {10.1016/j.phytochem.2017.08.018},
  pages     = {43 -- 51},
  year      = {2017},
  abstract  = {Mixing events in stratified lakes result in microalgae being exposed to varying conditions in light and organic carbon concentrations. Stratified lakes consist of an upper illuminated strata and a lower, darker strata where organic carbon accumulates. Therefore, in this contribution we explore the importance of dissolved organic carbon for growth under various light intensities by measuring some ecophysiological adaptations in two green microalgae. We compared the non-motile Chlorella vulgaris with the flagellated Chlamydomonas acidophila under auto-, mixo-, and heterotrophic growth conditions. In both algae the maximum photosynthetic and growth rates were highest under mixotrophy, and both algae appeared inhibited in their phosphorus acquisition under heterotrophy. Heterotrophic conditions provoked the largest differences as C. vulgaris produced chlorophyll a in darkness and grew as well as in autotrophic conditions, whereas Chl. acidophila bleached and could not grow heterotrophically. Although the fatty acid composition of both phytoplankton species differed, both species reacted in a similar way to changes in their growth conditions, mainly by a decrease of C18:3n-3 and an increase of C18:1n-9 from auto- to heterotrophic conditions. The two contrasting responses within the group of green microalgae suggest that dissolved organic carbon has a high deterministic potential to explain the survival and behaviour of green algae in the deeper strata of lakes.},
  language  = {en}
}
@article{vonCzapiewskiKreyeMutluetal.2013,
  author    = {von Czapiewski, Marc and Kreye, Oliver and Mutlu, Hatice and Meier, Michael A. R.},
  title     = {Cross-metathesis versus palladium-catalyzed C-H activation acetoxy ester functionalization of unsaturated fatty acid methyl esters},
  series = {European journal of lipid science and technology},
  volume    = {115},
  journal   = {European journal of lipid science and technology},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1438-7697},
  doi       = {10.1002/ejlt.201200196},
  pages     = {76 -- 85},
  year      = {2013},
  abstract  = {Two synthetic approaches to functionalize plant oil derived platform chemicals were investigated. For this purpose, methyl 10-undecenoate, which can be obtained by pyrolysis of castor oil, was used in olefin cross-metathesis under neat conditions forming an unsaturated a,?-acetoxy ester. A catalyst screening with 11 different ruthenium-based metathesis catalysts was performed, revealing that well-suited catalysts allow for full conversion and very good cross-metathesis selectivity at a loading of only 0.5?mol\%. An alternative possibility to the aforementioned synthetic method is a palladium-catalyzed reaction of methyl 10-undecenoate with acetic acid in the presence of dimethyl sulfoxide. Here, the formation of linear and branched unsaturated acetoxy esters as well as a ketone was observed. The conversion as well as the selectivity of this procedure was studied under different reaction conditions and compared to the cross-metathesis results. Based on the successful functionalization of methyl 10-undecenoate, methyl oleate was investigated in this palladium-catalyzed C?H activation reaction. Due to the lower reactivity of the internal double bond the desired acetoxy ester was only obtained in moderate conversion in this case. In summary, this study clearly shows that palladium-catalyzed functionalization of unsaturated fatty compounds via C?H activation is an attractive alternative to the well-established olefin cross-metathesis procedure.},
  language  = {en}
}