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31.
32.
Georgios Hadjigeorgiou Efthimios Dardiotis Georgios Tsivgoulis Triantafyllos Doskas Damianos Petrou Nikolaos Makris Nikolaos Vlaikidis Thomas Thomaidis Athanasios Kyritsis Nikolaos Fakas Xoulietta Treska Clementine Karageorgiou Stefania Sotirli Christos Giannoulis Dimitra Papadimitriou Ioannis Mylonas Evaggelos Kouremenos George S. Vlachos Dimitrios Georgiopoulos Despoina Mademtzoglou Michalis Vikelis Elias Zintzaras 《PloS one》2015,10(10)
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34.
Fiamegos YC Nanos CG Stalikas CD 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,813(1-2):89-94
A derivatization-extraction method that avoids tedious preconcentration steps is established in order to determine amino acids accurately at nanogram levels. The method involves conversion of the analytes of concern to N(O,S)-ethoxycarbonyl amino acid ethyl esters and subsequent extraction by single-drop microextraction (SDME) followed by GC analysis. The reaction proceeds smoothly and rapidly under ultrasonication which removes the bubbles from the bulk solution. Precision is acceptable and 12 non-hydrolyzed amino acids can be determined in urine in this manner. As long as the extraction conditions are consistently applied, quantitative analysis can be performed accurately. The limits of detection were satisfactory in the range 0.010-0.025 microg/ml for GC-FID and 0.26-68 ng/ml for GC-MS(SIM) with 1 ml sample volume. 相似文献
35.
Konstantinos Dafopoulos Christos Venetis Christina I Messini Spyros Pournaras George Anifandis Antonios Garas Ioannis E Messinis 《Reproductive biology and endocrinology : RB&E》2011,9(1):59
Objectives
It has been suggested that inhibin secretion is altered in women with the polycystic ovary syndrome (PCOS). However, the contribution of a preceding luteal phase has not been taken into account. The aim of the present study was to investigate whether progesterone in the context of a simulated luteal phase affects basal and FSH-induced inhibin secretion in women with PCOS and elevated LH. 相似文献36.
One-hundred and fifty different thermophilic bacteria isolated from a volcanic island were screened for detection of an alkane
hydroxylase gene using degenerated primers developed to amplify genes related to the Pseudomonas putida and Pseudomonas oleovorans alkane hydroxylases. Ten isolates carrying the alkJ gene were further characterized by 16s rDNA gene sequencing. Nine out of ten isolates were phylogenetically affiliated with
Geobacillus species and one isolate with Bacillus species. These isolates were able to grow in liquid cultures with crude oil as the sole carbon source and were found to degrade
long chain crude oil alkanes in a range between 46.64% and 87.68%. Results indicated that indigenous thermophilic hydrocarbon
degraders of Bacillus and Geobacillus species are of special significance as they could be efficiently used for bioremediation of oil-polluted soil and composting
processes. 相似文献
37.
Xue Bessie Su Menglu Wang Claudia Schaffner Olga O. Nerusheva Dean Clift Christos Spanos David A. Kelly Michael Tatham Andreas Wallek Yehui Wu Juri Rappsilber A. Arockia Jeyaprakash Zuzana Storchova Ronald T. Hay Adle L. Marston 《The Journal of cell biology》2021,220(7)
During mitosis, sister chromatids attach to microtubules from opposite poles, called biorientation. Sister chromatid cohesion resists microtubule forces, generating tension, which provides the signal that biorientation has occurred. How tension silences the surveillance pathways that prevent cell cycle progression and correct erroneous kinetochore–microtubule attachments remains unclear. Here we show that SUMOylation dampens error correction to allow stable sister kinetochore biorientation and timely anaphase onset. The Siz1/Siz2 SUMO ligases modify the pericentromere-localized shugoshin (Sgo1) protein before its tension-dependent release from chromatin. Sgo1 SUMOylation reduces its binding to protein phosphatase 2A (PP2A), and weakening of this interaction is important for stable biorientation. Unstable biorientation in SUMO-deficient cells is associated with persistence of the chromosome passenger complex (CPC) at centromeres, and SUMOylation of CPC subunit Bir1 also contributes to timely anaphase onset. We propose that SUMOylation acts in a combinatorial manner to facilitate dismantling of the error correction machinery within pericentromeres and thereby sharpen the metaphase–anaphase transition. 相似文献
38.
It has been recently shown numerically that sex enables selection for alleles that perform well across different genetic contexts, i.e., selection for mixability. Here we capture this result analytically in a simple case. This serves a dual purpose. First, it provides a clear distinction between fitness maximization and selection for mixability. Second, it points out a limitation of the traditional analytical approach as applied to mixability. 相似文献
39.
Christos Arvanitidis Georgios Chatzigeorgiou Drosos Koutsoubas Theodoros Kevrekidis Costas Dounas Anastasios Eleftheriou Panayota Koulouri Athanasios Mogias 《Helgoland Marine Research》2005,59(3):177-186
An attempt is made to compare the results of different rapid biodiversity assessment techniques at the pan-Mediterranean, sectorial and local levels. A uniform multivariate pattern exists at the pan-Mediterranean and national (sectorial) levels: lagoons can be different when they host only a few species, but as species numbers increase, lagoons become homogenous in composition. Multivariate techniques cannot distinguish anthropogenically-impacted lagoons from those, which are naturally disturbed. In the pan-Mediterranean context it is the higher taxonomic levels, but in the national and local context it is the most abundant macrobenthic groups (polychaetes, molluscs and crustaceans) and meiobenthos which provide patterns closest to that derived from the species level. Taxonomic distinctness indices applied to polychaete and mollusc inventories provide meaningful results at most levels and scales of observation. These indices seem to be robust enough to discriminate anthropogenically impacted from naturally disturbed lagoons. 相似文献
40.
Crystal structures and enzymatic properties of three formyltransferases from archaea: environmental adaptation and evolutionary relationship 下载免费PDF全文
Mamat B Roth A Grimm C Ermler U Tziatzios C Schubert D Thauer RK Shima S 《Protein science : a publication of the Protein Society》2002,11(9):2168-2178
Formyltransferase catalyzes the reversible formation of formylmethanofuran from N(5)-formyltetrahydromethanopterin and methanofuran, a reaction involved in the C1 metabolism of methanogenic and sulfate-reducing archaea. The crystal structure of the homotetrameric enzyme from Methanopyrus kandleri (growth temperature optimum 98 degrees C) has recently been solved at 1.65 A resolution. We report here the crystal structures of the formyltransferase from Methanosarcina barkeri (growth temperature optimum 37 degrees C) and from Archaeoglobus fulgidus (growth temperature optimum 83 degrees C) at 1.9 A and 2.0 A resolution, respectively. Comparison of the structures of the three enzymes revealed very similar folds. The most striking difference found was the negative surface charge, which was -32 for the M. kandleri enzyme, only -8 for the M. barkeri enzyme, and -11 for the A. fulgidus enzyme. The hydrophobic surface fraction was 50% for the M. kandleri enzyme, 56% for the M. barkeri enzyme, and 57% for the A. fulgidus enzyme. These differences most likely reflect the adaptation of the enzyme to different cytoplasmic concentrations of potassium cyclic 2,3-diphosphoglycerate, which are very high in M. kandleri (>1 M) and relatively low in M. barkeri and A. fulgidus. Formyltransferase is in a monomer/dimer/tetramer equilibrium that is dependent on the salt concentration. Only the dimers and tetramers are active, and only the tetramers are thermostable. The enzyme from M. kandleri is a tetramer, which is active and thermostable only at high concentrations of potassium phosphate (>1 M) or potassium cyclic 2,3-diphosphoglycerate. Conversely, the enzyme from M. barkeri and A. fulgidus already showed these properties, activity and stability, at much lower concentrations of these strong salting-out salts. 相似文献