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21.
A metal-binding member of the late embryogenesis abundant protein family transports iron in the phloem of Ricinus communis L 总被引:7,自引:0,他引:7
Kruger C Berkowitz O Stephan UW Hell R 《The Journal of biological chemistry》2002,277(28):25062-25069
The transport of metal micronutrients to developing organs in a plant is mediated primarily by the sieve elements. Ligands are thought to form complexes with the free ions in order to prevent cellular damage, but no binding partners have been unequivocally identified from plants so far. This study has used the phloem-mediated transport of micronutrients during the germination of the castor bean seedling to identify an iron transport protein (ITP). It is demonstrated that essentially all (55)Fe fed to seedlings is associated with the protein fraction of phloem exudate. It is shown that ITP carries iron in vivo and binds additional iron in vitro. ITP was purified to homogeneity from minute amounts of phloem exudate using immobilized metal ion affinity chromatography. It preferentially binds to Fe(3+) but not to Fe(2+) and also complexes Cu(2+), Zn(2+), and Mn(2+) in vitro. The corresponding cDNA of ITP was cloned using internal peptide fragments. The deduced protein of 96 amino acids shows high similarity to the stress-related family of late embryogenesis abundant proteins. Its predicted characteristics and its RNA expression pattern are consistent with a function in metal ion binding. The ITP from Ricinus provides the first identified micronutrient binding partner for phloem-mediated long distance transport in plants and is the first member of the late embryogenesis abundant protein family shown to have such a function. 相似文献
22.
Orr S Alexandre E Clark B Combes R Fels LM Gray N Jönsson-Rylander AC Helin H Koistinen J Oinonen T Richert L Ravid R Salonen J Teesalu T Thasler W Trafford J Van Der Valk J Von Versen R Weiss T Womack C Ylikomi T 《Cell and tissue banking》2002,3(2):133-137
This is a report of a workshop held on the establishment of human research tissue banking which was held in Levi, Finland
21–24 March 2002.There were 21 participants from 7 European countries. This meeting was attended by representatives from academia,
research tissue banks and from the Biotech and Pharmaceutical Industries. The principal aim of the workshop was to find a
way to progress the recommendations from ECVAM workshop 44 (ATLA 29, 125–134,2001) and ECVAM workshop 32 (ATLA 26, 763–777,
1998). The workshop represented the first unofficial meeting of the European Network of Research Tissue Banks (ENRTB) steering
group. It is expected that in the period preceding the next workshop the ENRTB steering group will co-ordinate the ethical,legislative
and organisational aspects of research tissue banking. Key issues dealt with by the Levi workshop included the practical aspects
of sharing expertise and experiences across the different European members. Such collaboration between research tissue banks
and end users of such material seeks to ultimately enable shared access to human tissue for medical and pharmaco-toxicological
research while maintaining strict adherence to differences in legal and ethical aspects related to the use of human tissue
in individual countries.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
23.
Lahm Harald Hoeflich Andreas Rieger Norman Wanke Rudiger Wolf Eckhard 《Transgenic research》1998,7(2):131-134
Conventional screening protocols for transgene integration in mice employ tail tips or blood samples as sources to obtain genomic DNA preparations. We have developed a simple alternative non-surgical method. Epithelial cells are scraped off the inner surface of the rectum with a sterile plastic inoculation loop and are lysed with Kawasaki buffer. The lysate can be directly examined in a polymerase chain reaction (PCR) analysis without any need for further DNA purification. This procedure causes minimal harm and stress to the animals and repeated samples can be obtained as often as necessary. This technique has been used successfully to identify transgenic mice from a number of different lines. The method allows quick screening of numerous animals and contributes to a reduction of the number of surgical biopsies required 相似文献
24.
Regulation of the transient receptor potential channel TRPA1 by its N-terminal ankyrin repeat domain
Vasilina Zayats Abdul Samad Babak Minofar Katherine E. Roelofs Thomas Stockner Rudiger Ettrich 《Journal of molecular modeling》2013,19(11):4689-4700
The transient receptor potential channel A1 (TRPA1) is unique among ion channels of higher vertebrates in that it harbors a large ankyrin repeat domain. The TRPA1 channel is expressed in the inner ear and in nociceptive neurons. It is involved in hearing as well as in the perception of pungent and irritant chemicals. The ankyrin repeat domain has special mechanical properties, which allows it to function as a soft spring that can be extended over a large range while maintaining structural integrity. A calcium-binding site has been experimentally identified within the ankyrin repeats. We built a model of the N-terminal 17 ankyrin repeat structure, including the calcium-binding EF-hand. In our simulations we find the calcium-bound state to be rigid as compared to the calcium-free state. While the end-to-end distance can change by almost 50% in the apo form, these fluctuations are strongly reduced by calcium binding. This increase in stiffness that constraints the end-to-end distance in the holo form is predicted to affect the force acting on the gate of the TRPA1 channel, thereby changing its open probability. Simulations of the transmembrane domain of TRPA1 show that residue N855, which has been associated with familial episodic pain syndrome, forms a strong link between the S4-S5 connecting helix and S1, thereby creating a direct force link between the N-terminus and the gate. The N855S mutation weakens this interaction, thereby reducing the communication between the N-terminus and the transmembrane part of TRPA1. 相似文献
25.
3′-phosphoadenosine 5′-phosphosulfate (PAPS) is synthesized in two steps by PAPS synthase (PAPSS). PAPSS is comprised of ATP sulfurylase (ATPS) and APS kinase (APSK) domain activities. ATPS combines inorganic sulfate with α-phosphoryl of ATP to form adenosine 5′-phosphosulfate (APS) and PPi. In the second step APS is phosphorylated at 3′-OH using another mole of ATP to form PAPS and ADP catalyzed by APSK. The transfer of gamma-phosphoryl from ATP onto 3′-OH requires Mg2+ and purported to involve residues D87GD89N. We report that mutation of either aspartic residue to alanine completely abolishes APSK activity in PAPS formation. PAPSS is an, unique enzyme that binds to four different nucleotides: ATP and APS on both ATPS and APSK domains and ADP and PAPS exclusively on the APSK domain. The thermodynamic binding and the catalytic interplay must be very tightly controlled to form the end-product PAPS in the forward direction. Though APS binds to ATPS and APSK, in ATPS domain, the APS is a product and for APSK it is a substrate. DGDN motif is absent in ATPS and present in APSK. Mutation of D87 and D89 did not hamper ATPS activity however abolished APSK activity severely. Thus, D87GD89N region is required for stabilization of Mg2+-ATP, in the process of splitting the γ-phosphoryl from ATP and transfer of γ-phosphoryl onto 3′-OH of APS to form PAPS a process that cannot be achieved by ATPS domain. In addition, gamma32P-ATP, trapped phosphoryl enzyme intermediate more with PAPSS2 than with PAPSS1. This suggests inherent active site residues could control novel catalytic differences. Molecular docking studies of hPAPSS1with ATP + Mg2+ and APS of wild type and mutants supports the experimental results. 相似文献
26.
Peter Recknagel Falk A. Gonnert Martin Westermann Sandro Lambeck Amelie Lupp Alain Rudiger Alex Dyson Jane E. Carré Andreas Kortgen Christoph Krafft Jürgen Popp Christoph Sponholz Valentin Fuhrmann Ingrid Hilger Ralf A. Claus Niels C. Riedemann Reinhard Wetzker Mervyn Singer Michael Trauner Michael Bauer 《PLoS medicine》2012,9(11)
Background
Hepatic dysfunction and jaundice are traditionally viewed as late features of sepsis and portend poor outcomes. We hypothesized that changes in liver function occur early in the onset of sepsis, yet pass undetected by standard laboratory tests.Methods and Findings
In a long-term rat model of faecal peritonitis, biotransformation and hepatobiliary transport were impaired, depending on subsequent disease severity, as early as 6 h after peritoneal contamination. Phosphatidylinositol-3-kinase (PI3K) signalling was simultaneously induced at this time point. At 15 h there was hepatocellular accumulation of bilirubin, bile acids, and xenobiotics, with disturbed bile acid conjugation and drug metabolism. Cholestasis was preceded by disruption of the bile acid and organic anion transport machinery at the canalicular pole. Inhibitors of PI3K partially prevented cytokine-induced loss of villi in cultured HepG2 cells. Notably, mice lacking the PI3Kγ gene were protected against cholestasis and impaired bile acid conjugation. This was partially confirmed by an increase in plasma bile acids (e.g., chenodeoxycholic acid [CDCA] and taurodeoxycholic acid [TDCA]) observed in 48 patients on the day severe sepsis was diagnosed; unlike bilirubin (area under the receiver-operating curve: 0.59), these bile acids predicted 28-d mortality with high sensitivity and specificity (area under the receiver-operating curve: CDCA: 0.77; TDCA: 0.72; CDCA+TDCA: 0.87).Conclusions
Liver dysfunction is an early and commonplace event in the rat model of sepsis studied here; PI3K signalling seems to play a crucial role. All aspects of hepatic biotransformation are affected, with severity relating to subsequent prognosis. Detected changes significantly precede conventional markers and are reflected by early alterations in plasma bile acids. These observations carry important implications for the diagnosis of liver dysfunction and pharmacotherapy in the critically ill. Further clinical work is necessary to extend these concepts into clinical practice. Please see later in the article for the Editors'' Summary 相似文献27.
Marie-Charlotte Domart Tina M. C. Hobday Christopher J. Peddie Gary H. C. Chung Alan Wang Karen Yeh Nirmal Jethwa Qifeng Zhang Michael J. O. Wakelam Rudiger Woscholski Richard D. Byrne Lucy M. Collinson Dominic L. Poccia Banafshé Larijani 《PloS one》2012,7(12)
The functions and morphology of cellular membranes are intimately related and depend not only on their protein content but also on the repertoire of lipids that comprise them. In the absence of in vivo data on lipid asymmetry in endomembranes, it has been argued that motors, scaffolding proteins or integral membrane proteins rather than non-lamellar bilayer lipids such as diacylglycerol (DAG), are responsible for shaping of organelles, local membrane curvature and fusion. The effects of direct alteration of levels of such lipids remain predominantly uninvestigated. Diacylglycerol (DAG) is a well documented second messenger. Here we demonstrate two additional conserved functions of DAG: a structural role in organelle morphology, and a role in localised extreme membrane curvature required for fusion for which proteins alone are insufficient. Acute and inducible DAG depletion results in failure of the nuclear envelope (NE) to reform at mitosis and reorganisation of the ER into multi-lamellar sheets as revealed by correlative light and electron microscopy and 3D reconstructions. Remarkably, depleted cells divide without a complete NE, and unless rescued by 1,2 or 1,3 DAG soon die. Attenuation of DAG levels by enzyme microinjection into echinoderm eggs and embryos also results in alterations of ER morphology and nuclear membrane fusion. Our findings demonstrate that DAG is an in vivo modulator of organelle morphology in mammalian and echinoderm cells, indicating a fundamental role conserved across the deuterostome superphylum. 相似文献
28.
29.
Yoshinori Asakawa Masao Toyota Tsunematsu Takemoto Rudiger Mues 《Phytochemistry》1981,20(12):2695-2699
Three liverworts, Trichocolea tomentella, Neotrichocolea bissethii and Trichocoleopsis sacculata belonging to Jungermanniales were chemically investigated. Isoprenyl benzoates are the important chemical markers of Trichocolea tomentella. Neotrichocolea bissethii elaborates sesquiterpenes as the major components. The sacculatane-type diterpenes and pinguisane-type sesquiterpenes are the significant chemosystematic markers of Trichocoleopsis sacculata. These three species are chemically quite different. Trichocoleopsis sacculata is chemically rather close to Porella species. The present chemical results support the recent morphological classification of the above three species proposed by Schuster. Some species of Jungermanniales are chemically identical to those of Metzgeriales and these results also support the phylogenetic classification in which the two orders have been united within the subclass Jungermanniae. 相似文献
30.
Rudiger Hartmann Dr. F. P. M 《Zoomorphology》1970,68(2):140-176
The tubular spermatophore of Gomphocerus rufus L. is formed 3 to 4 minutes after the begin of copulation; it consists of various proteins which are secreted by the 16 tubules of the paired accessory glands. Selective surgical ablation of the tubules indicate, that the secretion of the accessory glands serve the following functions: determination of the shape of the spermatophore, transmission of the pressure necessary for spermatophore transfer and formation of the lumen of the spermatophore. The course of production of the spermatophore has been studied.
Herrn Prof. Dr. W. Loher, University of California, Berkeley, danke ich herzlich fur die Stellung des Themas, für wertvolle Ratschläge bei der Durchführung der Arbeit and für seine Hilfe bei ihrer Abfassung. Herrn Prof. Dr. F. P. Möhres bin ich für die Überlassung eines Arbeitsplatzes zu großem Dank verpflichtet. Die Üntersuchungen wurden aus Mitteln der Deutschen Forschungsgemeinschaft unterstützt, die Prof. Loher zur Verfügung standen. 相似文献
Herrn Prof. Dr. W. Loher, University of California, Berkeley, danke ich herzlich fur die Stellung des Themas, für wertvolle Ratschläge bei der Durchführung der Arbeit and für seine Hilfe bei ihrer Abfassung. Herrn Prof. Dr. F. P. Möhres bin ich für die Überlassung eines Arbeitsplatzes zu großem Dank verpflichtet. Die Üntersuchungen wurden aus Mitteln der Deutschen Forschungsgemeinschaft unterstützt, die Prof. Loher zur Verfügung standen. 相似文献