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921.
Ali Azizi Carola Wagner Bernd Honermeier Wolfgang Friedt 《Plant Systematics and Evolution》2009,281(1-4):151-160
The genus Origanum is often referred to as an under-utilized taxon because of its complex taxonomy. Origanum vulgare L., the most variable species of the genus, is a spice and medicinal herb that is characterized by high morphological diversity (six subspecies). In this study, the relative efficiencies of two PCR-based marker approaches, amplified fragment length polymorphism (AFLP) and selectively amplified microsatellite polymorphic loci (SAMPL), were used for comparable genetic diversity surveys and subspecies discrimination among 42 oregano accessions. Seven assays each of AFLP and SAMPL markers were utilized. Effective multiplex ratio (EMR), average heterozygosity (Hav-p), marker index (MI), and resolving power (RP) of the primer combinations were calculated for the two marker systems. UPGMA and Structure analysis along with PCoA plots derived from the binary data matrices of the two markers depicted the genetic distinction of accessions. Our results indicate that both marker systems are suitable but SAMPL markers are slightly more efficient in differentiating accessions and subspecies than AFLPs. 相似文献
922.
The N-end rule degradation pathway states that the half-life of a protein is determined by the nature of its N-terminal residue. In Escherichia coli the adaptor protein ClpS directly interacts with destabilizing N-terminal residues and transfers them to the ClpA/ClpP proteolytic complex for degradation. The crucial role of ClpS in N-end rule degradation is currently under debate, since ClpA/ClpP was shown to process selected N-terminal degrons harbouring destabilizing residues in the absence of ClpS. Here, we investigated the contribution of ClpS to N-end rule degradation by two approaches. First, we performed a systematic mutagenesis of selected N-degron model substrates, demonstrating that ClpS but not ClpA specifically senses the nature of N-terminal residues. Second, we identified two natural N-end rule substrates of E. coli : Dps and PATase (YgjG). The in vivo degradation of both proteins strictly relied on ClpS, thereby establishing the function of ClpS as the essential discriminator of the E. coli N-end rule pathway. 相似文献
923.
Thomas C. Wanger Iris Motzke Samuel C. Furrer Barry W. Brook Bernd Gruber 《Ecological Research》2009,24(2):345-353
Rapid and reliable estimation of population size is needed for the efficient monitoring of animal populations of conservation
concern. Unfortunately, technical advances in this area have not been paralleled in uptake in conservation, which may be due
to difficulties in implementation or the lack of general guidelines for application. Here we tested five different methods
used to estimate population size [capture–mark–recapture (CMR), finite-mixture models, model averaging of finite-mixture models,
accumulation curve methods (ACM), and the line transect method (LT)] using extensive capture–recapture data of the giant day
gecko (Gekkonidae, Phelsuma madagascariensis grandis, Gray 1870) at the Masoala rainforest exhibit, Zurich Zoo. When the complete data were analyzed [30 sessions (and 27 sessions
for the LT)], all methods except the LT produced similar estimates of population size. The simple ACM gave a small coefficient
of variation (CV), but did not cover the most likely value of population size at moderate sampling effort. Nevertheless, the
ACM was the only method that showed a reasonable convergence when subsets of data were used. CMR and Pledger models included
the reference value in their confidence intervals (CI) after 25 and 30 sessions, respectively. Although model averaging did
slightly improve the estimate, the CV was still high for the full dataset. Our method of using subsets of data to test the
robustness of estimates is simple to apply and could be adopted more widely in such analyzes to evaluate sensitivity to method
of evaluation. In conclusion, simple accumulation methods showed similar efficiency to more complex statistical models, and
are likely to be sufficiently precise for most conservation monitoring purposes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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927.
Guido Achermann Theresa M. Ballard Francesca Blasco Pierre-Emmanuel Broutin Bernd Büttelmann Holger Fischer Martin Graf Maria-Clemencia Hernandez Peter Hilty Frédéric Knoflach Andreas Koblet Henner Knust Anke Kurt James R. Martin Raffaello Masciadri Richard H.P. Porter Heinz Stadler Andrew W. Thomas Gerhard Trube Jürgen Wichmann 《Bioorganic & medicinal chemistry letters》2009,19(19):5746-5752
Through iterative design cycles we have discovered a number of novel new classes where the imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4]benzodiazepine was deemed the most promising GABAA α5 inverse agonist class with potential for cognitive enhancement. This class combines a modest subtype binding selectivity with inverse agonism and has the most favourable molecular properties for further lead optimisation towards a central nervous system (CNS) acting medicine. 相似文献
928.
Nico Dissmeyer Annika K. Weimer Stefan Pusch Kristof De Schutter Claire Lessa Alvim Kamei Moritz K. Nowack Bela Novak Gui-Lan Duan Yong-Guan Zhu Lieven De Veylder Arp Schnittger 《The Plant cell》2009,21(11):3641-3654
Entry into mitosis is universally controlled by cyclin-dependent kinases (CDKs). A key regulatory event in metazoans and fission yeast is CDK activation by the removal of inhibitory phosphate groups in the ATP binding pocket catalyzed by Cdc25 phosphatases. In contrast with other multicellular organisms, we show here that in the flowering plant Arabidopsis thaliana, cell cycle control does not depend on sudden changes in the phosphorylation pattern of the PSTAIRE-containing Cdk1 homolog CDKA;1. Consistently, we found that neither mutants in a previously identified CDC25 candidate gene nor plants in which it is overexpressed display cell cycle defects. Inhibitory phosphorylation of CDKs is also the key event in metazoans to arrest cell cycle progression upon DNA damage. However, we show here that the DNA damage checkpoint in Arabidopsis can also operate independently of the phosphorylation of CDKA;1. These observations reveal a surprising degree of divergence in the circuitry of highly conserved core cell cycle regulators in multicellular organisms. Based on biomathematical simulations, we propose a plant-specific model of how progression through the cell cycle could be wired in Arabidopsis. 相似文献
929.
Iain D. Hay Kali Gatland Andrea Campisano J. Zoe Jordens Bernd H. A. Rehm 《Applied and environmental microbiology》2009,75(18):6022-6025
The supermucoid Pseudomonas aeruginosa strain PDO300Δalg8(pBBR1MCS-5:alg8) showed strongly impaired attachment compared with the respective mucoid or nonmucoid strains and formed a thicker biofilm with large extended mushroom-like microcolonies. Alginate lyase treatment dissolved microcolonies. The data suggested that alginate overproduction impairs attachment but plays a structural role in microcolony formation.Alginate is an important virulence factor for Pseudomonas aeruginosa, and the conversion of nonmucoid strains to alginate-overproducing mucoid strains early after the infection of cystic fibrosis patients is associated with a decline of pulmonary function and survival rate (11, 13). Alginate functions as extracellular matrix material, enabling the formation of differentiated biofilms in which the diffusion of clinical antibiotics is decreased and the embedded cells are protected against human antibacterial defense mechanisms (9, 12). Although alginate is not required for P. aeruginosa biofilm formation (15), previous studies have provided evidence that it plays a role in the formation of thick and three-dimensional biofilms (5, 9). To further investigate the impact of alginate on attachment and biofilm architecture, we used a recently generated supermucoid strain, PDO300Δalg8(pBBR1MCS-5:alg8) (14). This strain showed about 15-fold alginate overproduction compared to alginate-producing mucoid P. aeruginosa. The gene alg8 encodes the proposed catalytic subunit of alginate polymerase and is essential for alginate biosynthesis (14). 相似文献
930.
Parvana Hajieva Justyna B. Mocko Bernd Moosmann Christian Behl 《Journal of neurochemistry》2009,110(1):118-132
Strong evidence indicates that oxidative stress may be causally involved in the pathogenesis of Parkinson's disease. We have employed human dopaminergic neuroblastoma cells and rat primary mesencephalic neurons to assess the protective potential of three novel bisarylimine antioxidants on dopaminergic cell death induced by complex I inhibition or glutathione depletion. We have found that exceptionally low concentrations (EC50 values ∼20 nM) of these compounds (iminostilbene, phenothiazine, and phenoxazine) exhibited strong protective effects against the toxicities of MPP+ , rotenone, and l -buthionine sulfoximine. Investigating intracellular glutathione levels, it was found that MPP+ , l -buthionine sulfoximine, and rotenone disrupted different aspects of the native glutathione equilibrium, while the aromatic imines did not further influence glutathione levels or redox state on any baseline. However, the imines independently reduced protein oxidation and total oxidant flux, saved the mitochondrial membrane potential, and provided full cytoprotection under conditions of complete glutathione depletion. The unusually potent antioxidant effects of the bisarylimines could be reproduced in isolated mitochondria, which were instantly protected from lipid peroxidation and pathological swelling. Aromatic imines may be interesting lead structures for a potential antioxidant therapy of Parkinson's disease and other disorders accompanied by glutathione dysregulation. 相似文献