@article{HeinzeSimonsSeiboldetal.2019, author = {Heinze, Johannes and Simons, Nadja K. and Seibold, Sebastian and Wacker, Alexander and Weithoff, Guntram and Gossner, Martin M. and Prati, Daniel and Bezemer, T. Martijn and Joshi, Jasmin Radha}, title = {The relative importance of plant-soil feedbacks for plant-species performance increases with decreasing intensity of herbivory}, series = {Oecologia}, volume = {190}, journal = {Oecologia}, number = {3}, publisher = {Springer}, address = {New York}, issn = {0029-8549}, doi = {10.1007/s00442-019-04442-9}, pages = {651 -- 664}, year = {2019}, abstract = {Under natural conditions, aboveground herbivory and plant-soil feedbacks (PSFs) are omnipresent interactions strongly affecting individual plant performance. While recent research revealed that aboveground insect herbivory generally impacts the outcome of PSFs, no study tested to what extent the intensity of herbivory affects the outcome. This, however, is essential to estimate the contribution of PSFs to plant performance under natural conditions in the field. Here, we tested PSF effects both with and without exposure to aboveground herbivory for four common grass species in nine grasslands that formed a gradient of aboveground invertebrate herbivory. Without aboveground herbivores, PSFs for each of the four grass species were similar in each of the nine grasslands-both in direction and in magnitude. In the presence of herbivores, however, the PSFs differed from those measured under herbivory exclusion, and depended on the intensity of herbivory. At low levels of herbivory, PSFs were similar in the presence and absence of herbivores, but differed at high herbivory levels. While PSFs without herbivores remained similar along the gradient of herbivory intensity, increasing herbivory intensity mostly resulted in neutral PSFs in the presence of herbivores. This suggests that the relative importance of PSFs for plant-species performance in grassland communities decreases with increasing intensity of herbivory. Hence, PSFs might be more important for plant performance in ecosystems with low herbivore pressure than in ecosystems with large impacts of insect herbivores.}, language = {en} } @misc{KoussoroplisSchwarzenbergerWacker2017, author = {Koussoroplis, Apostolos-Manuel and Schwarzenberger, Anke and Wacker, Alexander}, title = {Diet quality determines lipase gene expression and lipase/esterase activity in Daphnia pulex}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-395661}, pages = {7}, year = {2017}, abstract = {We studied the short- (12 h) and long-term (144 h) response of Daphnia pulex lipases to quality shifts in diets consisting of different mixtures of the green alga Scenedesmus with the cyanobacterium Synechococcus, two species with contrasting lipid compositions. The lipase/esterase activity in both the gut and the body tissues had fast responses to the diet shift and increased with higher dietary contributions of Synechococcus. When screening the Daphnia genome for TAG lipases, we discovered a large gene-family expansion of these enzymes. We used a subset of eight genes for mRNA expression analyses and distinguished between influences of time and diet on the observed gene expression patterns. We identified five diet-responsive lipases of which three showed a sophisticated short- and long-term pattern of expression in response to small changes in food-quality. Furthermore, the gene expression of one of the lipases was strongly correlated to lipase/esterase activity in the gut suggesting its potentially major role in digestion. These findings demonstrate that the lipid-related enzymatic machinery of D. pulex is finely tuned to diet and might constitute an important mechanism of physiological adaptation in nutritionally complex environments.}, language = {en} } @article{KoussoroplisSchwarzenbergerWacker2017, author = {Koussoroplis, Apostolos-Manuel and Schwarzenberger, Anke and Wacker, Alexander}, title = {Diet quality determines lipase gene expression and lipase/esterase activity in Daphnia pulex}, series = {Biology open : BiO}, volume = {6}, journal = {Biology open : BiO}, publisher = {The company of Biologists}, address = {Cambridge}, doi = {10.1242/bio.022046}, pages = {210 -- 216}, year = {2017}, abstract = {We studied the short- (12 h) and long-term (144 h) response of Daphnia pulex lipases to quality shifts in diets consisting of different mixtures of the green alga Scenedesmus with the cyanobacterium Synechococcus, two species with contrasting lipid compositions. The lipase/esterase activity in both the gut and the body tissues had fast responses to the diet shift and increased with higher dietary contributions of Synechococcus. When screening the Daphnia genome for TAG lipases, we discovered a large gene-family expansion of these enzymes. We used a subset of eight genes for mRNA expression analyses and distinguished between influences of time and diet on the observed gene expression patterns. We identified five diet-responsive lipases of which three showed a sophisticated short- and long-term pattern of expression in response to small changes in food-quality. Furthermore, the gene expression of one of the lipases was strongly correlated to lipase/esterase activity in the gut suggesting its potentially major role in digestion. These findings demonstrate that the lipid-related enzymatic machinery of D. pulex is finely tuned to diet and might constitute an important mechanism of physiological adaptation in nutritionally complex environments.}, language = {en} }