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51.
Marleen Perseke Anja Golombek Martin Schlegel Torsten H. Struck 《Molecular phylogenetics and evolution》2013,66(3):898-905
Deuterostomia, one of the three major lineages of Bilateria, comprises many well-known animals such as vertebrates, sea squirts, sea stars and sea urchins. Whereas monophyly of Deuterostomia and several subtaxa is well supported, the relationships of these to each other and, hence, deuterostome relationships are still uncertain. To address these issues in deuterostome phylogeny we analyzed datasets comprising more than 300 complete deuterostome mitochondrial genomes. Based on sequence information, the results revealed support for several relationships such as a basal position of Xenoturbella within Deuterostomia or for taxa like Craniota or Ambulacraria, but yielded also problems in some taxa, e.g. Tunicata, Pterobranchia and Ophiuroidea, due to long-branch artifacts. However, within tunicates the relationships are well supported. Variation in the genetic code was also informative and, e.g., supported the taxon Ambulacraria including Pterobranchia. 相似文献
52.
Guillaume Allorent Ryutaro Tokutsu Thomas Roach Graham Peers Pierre Cardol Jacqueline Girard-Bascou Daphné Seigneurin-Berny Dimitris Petroutsos Marcel Kuntz Cécile Breyton Fabrice Franck Francis-André Wollman Krishna K. Niyogi Anja Krieger-Liszkay Jun Minagawa Giovanni Finazzi 《The Plant cell》2013,25(2):545-557
Absorption of light in excess of the capacity for photosynthetic electron transport is damaging to photosynthetic organisms. Several mechanisms exist to avoid photodamage, which are collectively referred to as nonphotochemical quenching. This term comprises at least two major processes. State transitions (qT) represent changes in the relative antenna sizes of photosystems II and I. High energy quenching (qE) is the increased thermal dissipation of light energy triggered by lumen acidification. To investigate the respective roles of qE and qT in photoprotection, a mutant (npq4 stt7-9) was generated in Chlamydomonas reinhardtii by crossing the state transition–deficient mutant (stt7-9) with a strain having a largely reduced qE capacity (npq4). The comparative phenotypic analysis of the wild type, single mutants, and double mutants reveals that both state transitions and qE are induced by high light. Moreover, the double mutant exhibits an increased photosensitivity with respect to the single mutants and the wild type. Therefore, we suggest that besides qE, state transitions also play a photoprotective role during high light acclimation of the cells, most likely by decreasing hydrogen peroxide production. These results are discussed in terms of the relative photoprotective benefit related to thermal dissipation of excess light and/or to the physical displacement of antennas from photosystem II. 相似文献
53.
Helga Joos Anja Wildner Cathrin Hogrefe Heiko Reichel Rolf E Brenner 《Arthritis research & therapy》2013,15(5):R119
Introduction
The repair capability of traumatized articular cartilage is highly limited so that joint injuries often lead to osteoarthritis. Migratory chondrogenic progenitor cells (CPC) might represent a target cell population for in situ regeneration. This study aims to clarify, whether 1) CPC are present in regions of macroscopically intact cartilage from human osteoarthritic joints, 2) CPC migration is stimulated by single growth factors and the cocktail of factors released from traumatized cartilage and 3) CPC migration is influenced by cytokines present in traumatized joints.Methods
We characterized the cells growing out from macroscopically intact human osteoarthritic cartilage using a panel of positive and negative surface markers and analyzed their differentiation capacity. The migratory response to platelet-derived growth factor (PDGF)-BB, insulin-like growth factor 1 (IGF-1), supernatants obtained from in vitro traumatized cartilage and interleukin-1 beta (IL-1β) as well as tumor necrosis factor alpha (TNF-α) were tested with a modified Boyden chamber assay. The influence of IL-1β and TNF-α was additionally examined by scratch assays and outgrowth experiments.Results
A comparison of 25 quadruplicate marker combinations in CPC and bone-marrow derived mesenchymal stromal cells showed a similar expression profile. CPC cultures had the potential for adipogenic, osteogenic and chondrogenic differentiation. PDGF-BB and IGF-1, such as the supernatant from traumatized cartilage, induced a significant site-directed migratory response. IL-1β and TNF-α significantly reduced basal cell migration and abrogated the stimulative effect of the growth factors and the trauma supernatant. Both cytokines also inhibited cell migration in the scratch assay and primary outgrowth of CPC from cartilage tissue. In contrast, the cytokine IL-6, which is present in trauma supernatant, did not affect growth factor induced migration of CPC.Conclusion
These results indicate that traumatized cartilage releases chemoattractive factors for CPC but IL-1β and TNF-α inhibit their migratory activity which might contribute to the low regenerative potential of cartilage in vivo. 相似文献54.
55.
56.
Carsten Frühbeis Dominik Fr?hlich Wen Ping Kuo Jesa Amphornrat Sebastian Thilemann Aiman S. Saab Frank Kirchhoff Wiebke M?bius Sandra Goebbels Klaus-Armin Nave Anja Schneider Mikael Simons Matthias Klugmann Jacqueline Trotter Eva-Maria Kr?mer-Albers 《PLoS biology》2013,11(7)
Reciprocal interactions between neurons and oligodendrocytes are not only crucial for myelination, but also for long-term survival of axons. Degeneration of axons occurs in several human myelin diseases, however the molecular mechanisms of axon-glia communication maintaining axon integrity are poorly understood. Here, we describe the signal-mediated transfer of exosomes from oligodendrocytes to neurons. These endosome-derived vesicles are secreted by oligodendrocytes and carry specific protein and RNA cargo. We show that activity-dependent release of the neurotransmitter glutamate triggers oligodendroglial exosome secretion mediated by Ca2+ entry through oligodendroglial NMDA and AMPA receptors. In turn, neurons internalize the released exosomes by endocytosis. Injection of oligodendroglia-derived exosomes into the mouse brain results in functional retrieval of exosome cargo in neurons. Supply of cultured neurons with oligodendroglial exosomes improves neuronal viability under conditions of cell stress. These findings indicate that oligodendroglial exosomes participate in a novel mode of bidirectional neuron-glia communication contributing to neuronal integrity. 相似文献
57.
Roel J. T. Mocking Anja Lok Johanna Assies Maarten W. J. Koeter Ieke Visser Henricus G. Ruhé Claudi L. H. Bockting Aart H. Schene 《PloS one》2013,8(12)
Background
Fatty acid (FA)-alterations may mediate the mutual association between Major Depressive Disorder (MDD) and cardiovascular disease (CVD). However, etiology of observed FA-alterations in MDD and CVD remains largely unclear. An interesting candidate may be a mutation in the fatty acid–binding protein 2 (FABP2)-gene, because it regulates dietary FA-uptake. Therefore, we aimed to test the hypotheses that in MDD-patients the FABP2 Ala54Thr-polymorphism would be (I) more prevalent than in sex- and age-matched controls, (II) associated with observed alterations in FA-metabolism, and (III) associated with CVD-risk factor waist circumference.Methods
We measured concentrations of 29 different erythrocyte FAs, FABP2-genotype, and waist circumference in recurrent MDD-patients and matched never-depressed controls.Results
FABP2-genotype distribution did not significantly differ between the 137 MDD-patients and 73 matched controls. However, patients with the Ala54Thr-polymorphism had (I) higher concentrations of especially eicosadienoic acid (C20:2ω6; P=.009) and other 20-carbon FAs, and associated (II) lower waist circumference (P=.019). In addition, FABP2-genotype effects on waist circumference in patients seemed (I) mediated by its effect on C20:2ω6, and (II) different from controls.Conclusions
Although Ala54Thr-polymorphism distribution was not associated with recurrent MDD, our results indicate that FABP2 may play a role in the explanation of observed FA-alterations in MDD. For Ala54Thr-polymorphism patients, potentially adaptive conversion of increased bioavailable dietary precursors into eicosadienoic acid instead of arachidonic acid might be related to a low waist circumference. Because this is the first investigation of these associations, replication is warranted, preferably by nutrigenetic studies applying lipidomics and detailed dietary assessment. 相似文献58.
59.
Wenli Zhang Manish Solanki Nadine Müther Melanie Ebel Jichang Wang Chuanbo Sun Zsuzsanna Izsvak Anja Ehrhardt 《PloS one》2013,8(10)
Recombinant adeno-associated viral (AAV) vectors have been shown to be one of the most promising vectors for therapeutic gene delivery because they can induce efficient and long-term transduction in non-dividing cells with negligible side-effects. However, as AAV vectors mostly remain episomal, vector genomes and transgene expression are lost in dividing cells. Therefore, to stably transduce cells, we developed a novel AAV/transposase hybrid-vector. To facilitate SB-mediated transposition from the rAAV genome, we established a system in which one AAV vector contains the transposon with the gene of interest and the second vector delivers the hyperactive Sleeping Beauty (SB) transposase SB100X. Human cells were infected with the AAV-transposon vector and the transposase was provided in trans either by transient and stable plasmid transfection or by AAV vector transduction. We found that groups which received the hyperactive transposase SB100X showed significantly increased colony forming numbers indicating enhanced integration efficiencies. Furthermore, we found that transgene copy numbers in transduced cells were dose-dependent and that predominantly SB transposase-mediated transposition contributed to stabilization of the transgene. Based on a plasmid rescue strategy and a linear-amplification mediated PCR (LAM-PCR) protocol we analysed the SB100X-mediated integration profile after transposition from the AAV vector. A total of 1840 integration events were identified which revealed a close to random integration profile. In summary, we show for the first time that AAV vectors can serve as template for SB transposase mediated somatic integration. We developed the first prototype of this hybrid-vector system which with further improvements may be explored for treatment of diseases which originate from rapidly dividing cells. 相似文献
60.