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451.
The ABC maltose transporter 总被引:6,自引:0,他引:6
Michael Ehrmann Rainer Ehrle Eckhard Hofmann Winfried Boos & Andreas Schlösser 《Molecular microbiology》1998,29(3):685-694
Bacterial ATP-binding cassette (ABC) transporters and their homologues in eukaryotic cells form one of the largest superfamilies known today. They function as primary pumps that couple substrate translocation across the cytoplasmic membrane to ATP hydrolysis. Although ABC transporters have been studied for more than three decades, the structure of these multicomponent systems is unknown, and the mechanism of transport is not understood. This article reviews one of the most widely studied ABC systems, the maltose transporter of Escherichia coli . A first structural model of the transport channel allows discussion of possible mechanisms of transport. In addition, recent experimental evidence suggests that regulation of gene expression and transport activity is far more complex than expected. 相似文献
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K van Oers A W Santure I De Cauwer N EM van Bers R PMA Crooijmans B C Sheldon M E Visser J Slate M AM Groenen 《Heredity》2014,112(3):307-316
Linking variation in quantitative traits to variation in the genome is an important, but
challenging task in the study of life-history evolution. Linkage maps provide a valuable
tool for the unravelling of such trait−gene associations. Moreover, they give
insight into recombination landscapes and between-species karyotype evolution. Here we
used genotype data, generated from a 10k single-nucleotide polymorphism (SNP) chip, of
over 2000 individuals to produce high-density linkage maps of the great tit (Parus
major), a passerine bird that serves as a model species for ecological and
evolutionary questions. We created independent maps from two distinct populations: a
captive F2-cross from The Netherlands (NL) and a wild population from the United Kingdom
(UK). The two maps contained 6554 SNPs in 32 linkage groups, spanning 2010 cM and
1917 cM for the NL and UK populations, respectively, and were similar in size and
marker order. Subtle levels of heterochiasmy within and between chromosomes were
remarkably consistent between the populations, suggesting that the local departures from
sex-equal recombination rates have evolved. This key and surprising result would have been
impossible to detect if only one population was mapped. A comparison with zebra finch
Taeniopygia guttata, chicken Gallus gallus and the green anole lizard
Anolis carolinensis genomes provided further insight into the evolution of
avian karyotypes. 相似文献
455.
Raymund E. Horch Anja M. Boos Yuan Quan Oliver Bleiziffer Rainer Detsch Aldo R. Boccaccini Christoph Alexiou Jiaming Sun Justus P. Beier Andreas Arkudas 《Journal of cellular and molecular medicine》2013,17(10):1197-1206
Tissue engineering (TE) has evoked new hopes for the cure of organ failure and tissue loss by creating functional substitutes in the laboratory. Besides various innovations in the context of Regenerative Medicine (RM), TE also provided new technology platforms to study mechanisms of angiogenesis and tumour cell growth as well as potentially tumour cell spreading in cancer research. Recent advances in stem cell technology – including embryonic and adult stem cells and induced pluripotent stem cells – clearly show the need to better understand all relevant mechanisms to control cell growth when such techniques will be administered to patients. Such TE‐Cancer research models allow us to investigate the interactions that occur when replicating physiological and pathological conditions during the initial phases of replication, morphogenesis, differentiation and growth under variable given conditions. Tissue microenvironment has been extensively studied in many areas of TE and it plays a crucial role in cell signalling and regulation of normal and malignant cell functions. This article is intended to give an overview on some of the most recent developments and possible applications of TE and RM methods with regard to the improvement of cancer research with TE platforms. The synthesis of TE with innovative methods of molecular biology and stem‐cell technology may help investigate and potentially modulate principal phenomena of tumour growth and spreading, as well as tumour‐related angiogenesis. In the future, these models have the potential to investigate the optimal materials, culture conditions and material structure to propagate tumour growth. 相似文献
456.
Zuoxiang Yu Douglas Westerlund Karl-Siegfried Boos 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,689(2):410
A simple, sensitive and fully automated column-switching system by direct injection of plasma samples for determination of methotrexate and its metabolite 7-hydroxymethotrexate was developed. The system utilized a C8 alkyl-diol silica precolumn coupled with a LiChrospher RP-18 analytical column, followed by a photoreactor and fluorimetric detection. The photo-oxidative irradiation was accomplished at UV 254 nm in the presence of 0.1% hydrogen peroxide in the eluent. Studies showed that the fluorimetric response was influenced by the reaction time, the degree of the reactor's transparency and the choice of the working wavelengths. By optimizing the content of acetonitrile in the eluent, methotrexate can be separated from 7-hydroxymethotrexate completely. The method validation revealed quantitative recoveries (≥94%) with coefficients of variation ≤4.4%. The limits of detection and quantitation for determination of methotrexate were 0.20 and 0.36 ng, respectively, corresponding to 2.0 and 3.6 ng/ml for an injection volume of 100 μl. It was possible to enhance the sensitivity further by injecting larger plasma volumes, up to 500 μl. 相似文献
457.
Y S Kim P E Kolattukudy A Boos 《Comparative biochemistry and physiology. B, Comparative biochemistry》1979,62(4):443-447
1. Uropygial glands of domestic goose and mallard which synthesize methyl-branched fatty acids, contain large quantities of cytosolic malonyl-CoA decarboxylase and a small quantity of mitochondrial enzyme. 2. Uropygial glands of chicken and the liver of geese which generate little methyl-branched acids, contain only small quantities of malonyl-CoA decarboxylase and in such cases the enzyme is in the mitochondria. 3. The mitochondrial decarboxylase from the uropygial gland and liver of goose is immunologically similar to the cytosolic decarboxylase of the uropygial gland. 4. The mitochondrial enzyme probably protects the mitochondrial enzymes which are susceptible to inhibition by malonyl-CoA, whereas the cytosolic enzyme promotes the synthesis of methyl-branched acids. 相似文献
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