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SRS (Sequence Retrieval System), an indexing system for flatfile libraries, provides fast access to individual library entriesvia retrie by keywords from rious data fields. SRS is now alsoable to build indices using cross–references that mostlibraries provide. Fifteen libraries of DNA and protein sequencesand structures have been selected. These libraries interactwith at least one other by means of cross–references.Indexing these cross–references allows a complete networkof libraries to be built. In the network an entry from one librarycan be linked in principle to every other library. If two librariesare not directly cross–referenced, the linkage can bemade with a succession of single links between neighbouring,cross–referenced libraries. A new operator has been addedto the query language of SRS for convenient specification oflinks amongst complete libraries or entry sets generated byprevious queries on particular libraries. All the informationin the network can now be used to retrieve an entry in a specificlibrary, e.g. the full information given in amino acid sequenceentries from SwissProt can now be used to retrieve related tertiarystructure entries from PDB. Furthermore, a search in a singlelibrary can be extended to a search in the complete librarynetwork, e.g. all entries in all databases pertaining to elastasecan be found.  相似文献   
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Summary Experiments designed to establish stable chloroplast transformation require selectable marker genes encoded by the chloroplast genome. The antibiotic lincomycin is a specific inhibitor of chloroplast ribosomal activity and is known to bind to the large ribosomal subunit. We have investigated a defined region of the chloroplast 23 S rRNA genes from four lincomycin resistant Nicotiana plumbaginifolia mutants and from wild-type N. plumbaginifolia. The mutants LR415, LR421 and LR446 have A to G transitions at positions equivalent to the nucleotides 2058 and 2059 in the Escherichia coli 23 S rRNA. The mutant, LR400, possesses a G to A transition at a position corresponding to nucleotide 2032 of the E. coli 23 S rRNA.  相似文献   
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Key message

Relevance of spring temperatures for tree-ring growth steadily increased since 1950s. Closely linked tree-ring growth and net CO 2 exchange driven by spring temperatures.

Abstract

We investigated long-term (over 100 years) tree-ring width (TRW) variabilities as well as short-term (10 years) variations in net ecosystem productivity (NEP) in response to climate to assess the driving factors for stem growth of Norway spruce in a subalpine forest at Davos in Switzerland. A tree-ring width index (TRWi) chronology for the period from 1750 to 2006 was constructed and linked with climate data from 1876 to 2006, and with NEP available for the period from 1997 to 2006. Based on TRWi, we found that only two out of the 257 years exhibited extreme negative TRWi, compared to 29 years with extreme positive anomalies, observed mainly in recent decades. Annual temperature, annual precipitation, as well as autumn and winter temperature signals were well preserved in the TRWi chronology over the last 130 years. Spring temperatures became increasingly relevant for TRWi, explaining less than 1 % of the variation in TRWi for the period from 1876 to 2006, but 8 % for the period from 1950 to 2006 (p = 0.032), and even 47 % for 1997–2006 (p = 0.028). We also observed a strong positive relationship between annual TRWi and annual NEP (r = 0.661; p = 0.037), both strongly related to spring temperatures (r = 0.687 and r = 0.678 for TRWi and NEP, respectively; p = 0.028; p = 0.032). Moreover, we found strong links between monthly NEP of March and annual TRWi (r = 0.912; p = 0.0001), both related to March temperatures (r = 0.767, p = 0.010 and r = 0.724, p = 0.018, respectively). Thus, under future climate warming, we expect stem growth of these subalpine trees and also ecosystem carbon (C) sequestration to increase, as long as water does not become a limiting factor.  相似文献   
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The development of a pulse-driven loop reactor (PDLR), a pulsed anaerobic filter (PAF) and a pulsed anaerobic baffled reactor (PABR) is described. In an anaerobic PDLR internal circulation is achieved by a specially designed pulse-nozzle. In a PAF and PABR an oscillation is superimposed onto the liquid content of the fermenters by means of a pulse pump without any moving devices in the reactors. Pulsed digesters faciliate degassing, avoid reactor clogging as well as short-circuiting and allow a variety of packed-bed to fluidized-bed operations. Anaerobic fermentation of acetic acid and distillery slops in pulsed digesters on a laboratory scale shows that hydrodynamic stress caused by pulsation is well compatible to degrading bacteria.List of Symbols PAF Pulsed Anaerobic Filter - PDLR Pulse-Driven Loop Reactor - PABR Pulsed Anaerobic Baffled Reactor  相似文献   
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In simple epithelial cells, apical and basolateral proteins and lipids in transit to the cell surface are sorted in the trans-Golgi network. We have recently isolated detergent-insoluble complexes from Madin-Darby canine kidney cells that are enriched in glycosphingolipids, apical cargo and a subset of the proteins of the exocytic carrier vesicles. The vesicular proteins are thought to be involved in protein sorting and include VIP21-caveolin. The vesicular protein VIP36 (36 kDa vesicular integral membrane protein) has been purified from a CHAPS-insoluble residue and a cDNA encoding VIP36 has been isolated. The N-terminal 31 kDa luminal/exoplasmic domain of the encoded protein shows homology to leguminous plant lectins. The transiently expressed protein is localized to the Golgi apparatus, endosomal and vesicular structures and the plasma membrane, as predicted for a protein involved in transport between the Golgi and the cell surface. It is diffusely localized on the plasma membrane but can be redistributed by antibody modulation into caveolae and clathrin-coated pits. We speculate that VIP36 binds to sugar residues of glycosphingolipids and/or glycosylphosphatidyl-inositol anchors and might provide a link between the extracellular/luminal face of glycolipid rafts and the cytoplasmic protein segregation machinery.  相似文献   
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A translocation 2/6 inherited for 3 generations is described. The propositus, carrier of a partial trisomy 2p, showed multiple morphological anomalies of which microphtalmus and persistance of primary vitreous body were of particular interest. Based on a comparison of this with seven other patients in the literature, the most characteristic clinical symptoms of partial trisomy 2p are concluded to be the following: abundant lanugo at birth, glabella prominence, anteverted nares, dermatoglyphic anomalies, and malformations of the eyes.  相似文献   
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The mucus layer covering the gastrointestinal (GI) epithelium is critical in selecting and maintaining homeostatic interactions with our gut bacteria. However, the underpinning mechanisms of these interactions are not understood. Here, we provide structural and functional insights into the canonical mucus‐binding protein (MUB), a multi‐repeat cell‐surface adhesin found in Lactobacillus inhabitants of the GI tract. X‐ray crystallography together with small‐angle X‐ray scattering demonstrated a ‘beads on a string’ arrangement of repeats, generating 174 nm long protein fibrils, as shown by atomic force microscopy. Each repeat consists of tandemly arranged Ig‐ and mucin‐binding protein (MucBP) modules. The binding of full‐length MUB was confined to mucus via multiple interactions involving terminal sialylated mucin glycans. While individual MUB domains showed structural similarity to fimbrial proteins from Gram‐positive pathogens, the particular organization of MUB provides a structural explanation for the mechanisms in which lactobacilli have adapted to their host niche by maximizing interactions with the mucus receptors, potentiating the retention of bacteria within the mucus layer. Together, this study reveals functional and structural features which may affect tropism of microbes across mucus and along the GI tract, providing unique insights into the mechanisms adopted by commensals and probiotics to adapt to the mucosal environment.  相似文献   
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