TY - JOUR A1 - Denoux, Clemence A1 - Martin-Creuzburg, Dominik A1 - Koussoroplis, Apostolos-Manuel A1 - Perriere, Fanny A1 - Desvillettes, Christian A1 - Bourdier, Gilles A1 - Bec, Alexandre T1 - Phospholipid-bound eicosapentaenoic acid (EPA) supports higher fecundity than free EPA in Daphnia magna JF - Journal of plankton research N2 - Nutrition bioassays in which polyunsaturated fatty acids (PUFA)-deficient diets were supplemented with free long-chain PUFA (>= C20) consistently revealed positive effects on somatic growth and fecundity of Daphnia. However, free PUFA are hardly available in natural diets. In general, PUFA are bound to other lipids, especially to phospholipids and triglycerides. Here, we evaluate the potential of free and phospholipid-bound dietary eicosapentaenoic acid (EPA) to support somatic growth and fecundity of Daphnia magna. In a growth experiment, supplementation of a C20 PUFA-deficient diet with free or phospholipid-bound EPA improved somatic growth rates of D. magna equally. However, the increase in fecundity was significantly more pronounced when phospholipid-bound EPA was provided. Free and phospholipid-bound EPA were provided in the same concentrations in our experiment, suggesting that the allocation to reproduction-related processes is affected differently by phospholipid-bound PUFA and free PUFA. Our finding stresses the need to consider the distribution of dietary PUFA in different lipid classes to gain a better understanding of how PUFA influence life history traits of Daphnids in the field. KW - Daphnia magna KW - food quality KW - phospholipids KW - polyunsaturated fatty acids KW - reproduction KW - somatic growth KW - trophic interactions Y1 - 2017 U6 - https://doi.org/10.1093/plankt/fbx037 SN - 0142-7873 SN - 1464-3774 VL - 39 SP - 843 EP - 848 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Grimm, Christiane A1 - Meyer, Thomas A1 - Czapla, Sylvia A1 - Nikolaus, Jörg A1 - Scheidt, Holger A. A1 - Vogel, Alexander A1 - Herrmann, Andreas A1 - Wessig, Pablo A1 - Huster, Daniel A1 - Müller, Peter T1 - Structure and dynamics of molecular rods in membranes application of a Spin-Labeled rod JF - Chemistry - a European journal N2 - Molecular rods consisting of a hydrophobic backbone and terminally varying functional groups have been synthesized for applications for the functionalization of membranes. In the present study, we employ a spin-labeled analogue of a recently described new class of molecular rods to characterize their dynamic interactions with membranes. By using the different approaches of ESR and NMR spectroscopy, we show that the spin moiety of the membrane-embedded spin-labeled rod is localized in the upper chain/glycerol region of membranes of different compositions. The rod is embedded within the membrane in a tilted orientation to adjust for the varying hydrophobic thicknesses of these bilayers. This orientation does not perturb the membrane structure. The water solubility of the rod is increased significantly in the presence of certain cyclodextrins. These cyclodextrins also allow the rods to be extracted from the membrane and incorporated into preformed membranes. The latter will improve the future applications of these rods in cellular systems as stable membrane-associated anchors for the functionalization of membrane surfaces. KW - hydrophobic mismatch KW - membranes KW - molecular rods KW - phospholipids KW - spiro compounds Y1 - 2013 U6 - https://doi.org/10.1002/chem.201202500 SN - 0947-6539 VL - 19 IS - 8 SP - 2703 EP - 2710 PB - Wiley-VCH CY - Weinheim ER - TY - THES A1 - Nerlich, Annika T1 - Die Rolle der Phosphatidylserin Decarboxylase für die mitochondriale Phospholipid-Biosynthese in Arabidopsis thaliana T1 - Role of phosphatidylserine decarboxylase in mitochondrial phospholipid biosynthesis of Arabidopsis thaliana N2 - Die durch Phosphatidylserin Decarboxylase (PSD) katalysierte Decarboxylierung von Phosphatidylserin (PS) zu Phosphatidylethanolamin (PE) ist für Mitochondrien in Hefe und Mäusen von essentieller Bedeutung. Im Rahmen der vorliegenden Dissertation wurde erstmals die Rolle dieses PE-Syntheseweges in Pflanzen untersucht. Die drei in Arabidopsis identifizierten PSD Gene atPSD1, atPSD2, atPSD3 codieren für Enzyme, die in Membranen der Mitochondrien (atPSD1), der Tonoplasten (atPSD2) und des Endoplasmatischen Retikulums (atPSD3) lokalisiert sind. Der Beitrag der einzelnen PSDs zur PE-Synthese wurde anhand von psd Null-Mutanten untersucht. Dabei stellte sich atPSD3 als das Enzym mit der höchsten Aktivität heraus. Alternativ zum PSD-Weg wird in Arabidopsis PE auch mittels Aminoalkohol-phosphotransferase synthetisiert. Der Verlust der gesamten PSD-Aktivität, wie es in der erzeugten psd Dreifachmutante der Fall ist, wirkt sich ausschließlich auf die Lipidzusammensetzung in der Mitochondrienmembran aus. Demzufolge wird extramitochondriales PE hauptsächlich über die Aminoalkoholphosphotransferase synthetisiert. Die veränderte Lipidzusammensetzung der Mitochondrienmembran hatte jedoch keinen Einfluss auf die Anzahl, Größe und Ultrastruktur der Mitochondrien sowie auf das ADP/ATP-Verhältnis und die Respiration. Neben der Bereitstellung von Reduktionsäquivalenten beeinflusst die Funktionalität der Mitochondrien auch die Bildung von Blüten- und Staubblättern. Diese Blütenorgane waren in der psd Dreifachmutante stark verändert, und der Blütenphänotyp ähnelte der APETALA3-Mutante. Dieses homöotische Gen ist für die Ausbildung von Blüten- und Staubblättern verantwortlich. Für die Erzeugung der Mutanten psd2-1 und psd3-1 wurde ein T-DNA Vektor verwendet, der den Promotor des APETALA3 Gens enthielt, welcher in den Mutanten psd2-1, psd3-1 sowie psd2-1psd3-1 und der psd1psd2-1psd3-1 Dreifachmutante eine vergleichbare Co-Suppression des APETALA3 Gens hervorruft. Der Blütenphänotyp trat jedoch nur in der psd Dreifachmutante auf, da nur in ihr die Kombination von geringen Funktionstörungen der Mitochondrien, hervorgerufen durch veränderte Lipidzusammensetzung, mit der Co-Suppression von APETALA3 auftritt. N2 - Decarboxylation of phosphatidylserine (PS) to form phosphatidylethanolamine (PE) catalyzed by phosphatidylserine decarboxylase (PSD) is an essential reaction for mitochondria in yeast and mice. This dissertation describes the role of this biosynthesis pathway in plants for the first time. Three PSD genes were identified in Arabidopsis, atPSD1, atPSD2, atPSD3. The gene products localize to mitochondria (atPSD1), tonoplast (atPSD2) and endoplasmatic retikulum (atPSD3). Contribution to PE-synthesis of each PSD was analyzed using T-DNA insertion mutants. Thereby, atPSD3 was found to be the most active isoform. Alternatively, PE is also synthesized by the action of aminoalcohol phosphotransferase. Complete loss of PSD activity, like in the psd triple mutant, resulted in changes in lipid composition of mitochondria membranes exclusively. In conclusion the bulk of PE is synthesized by aminoalcohol phosphotransferase. Changed lipid composition of mitochondria did not result in changes of mitochondria number, structure, ADP/ATP ratio and respiration. Mitochondria functionality was formerly shown to effect formation of petals and stamens. These flower organs were drastically morphologically changed in psd triple mutants and showed strong similarities to APETALA3 mutants. APETALA3 is a homeotic gene responsible for specifying petals and stamens. Mutants psd2-1 and psd3-1 used for crossing psd double and triple mutants contained a T-DNA vector which include the promoter for APETALA3. This promoter caused co-suppression of the endogenous APETALA3 gene in all mutants isolated from the Arabidopsis Knockout Facility, whereas changed flower morphology occurred only in the triple mutant concluding a combined effect of co-suppression and a reduced functionality of mitochondria, caused by changed lipid composition. KW - Phospholipide KW - Phosphatidylserin Decarboxylase KW - Phosphatidylserin KW - Phosphatidylethanolamin KW - Mitochondrien KW - phospholipids KW - phosphatidylserine decarboxylase KW - phosphatidylserine KW - phosphatidylethanolamine KW - mitochondria Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14522 ER -