title: Diet quality determines lipase gene expression and lipase/esterase activity inDaphnia pulex.
abstract: We studied the short- (12 h) and long-term (144 h) response ofDaphnia pulexlipases to quality shifts in diets consisting of different mixtures of the green algaScenedesmuswith the cyanobacteriumSynechococcus, 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 ofSynechococcusWhen screening theDaphniagenome 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 ofD. pulexis finely tuned to diet and might constitute an important mechanism of physiological adaptation in nutritionally complex environments.
authors.affiliation: Theoretical Aquatic Ecology an Ecophysiology Group, Institute for Biochemistry and Biology, University of Potsdam, 14469 Potsdam, Germany apostolos.koussoroplis@uni-potsdam.de.
authors.forename: Apostolos-Manuel
authors.identifier: http://orcid.org/0000-0002-5218-5604
authors.initials: AM
authors.lastname: Koussoroplis
authors.affiliation: Theoretical Aquatic Ecology an Ecophysiology Group, Institute for Biochemistry and Biology, University of Potsdam, 14469 Potsdam, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Schwarzenberger
authors.affiliation: Theoretical Aquatic Ecology an Ecophysiology Group, Institute for Biochemistry and Biology, University of Potsdam, 14469 Potsdam, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Wacker
keywords: Cyanobacteria; Digestive enzyme activity; Lipases; Nutritional quality