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41.
Structure of internalin,a major invasion protein of Listeria monocytogenes,in complex with its human receptor E-cadherin 总被引:13,自引:0,他引:13
Schubert WD Urbanke C Ziehm T Beier V Machner MP Domann E Wehland J Chakraborty T Heinz DW 《Cell》2002,111(6):825-836
Listeria monocytogenes, a food-borne bacterial pathogen, enters mammalian cells by inducing its own phagocytosis. The listerial protein internalin (InlA) mediates bacterial adhesion and invasion of epithelial cells in the human intestine through specific interaction with its host cell receptor E-cadherin. We present the crystal structures of the functional domain of InlA alone and in a complex with the extracellular, N-terminal domain of human E-cadherin (hEC1). The leucine rich repeat (LRR) domain of InlA surrounds and specifically recognizes hEC1. Individual interactions were probed by mutagenesis and analytical ultracentrifugation. These include Pro16 of hEC1, a major determinant for human susceptibility to L. monocytogenes infection that is essential for intermolecular recognition. Our studies reveal the structural basis for host tro-pism of this bacterium and the molecular deception L. monocytogenes employs to exploit the E-cadherin system. 相似文献
42.
Rudi Verovnik Branko Micevski Dirk Maes Irma Wynhoff Chris Van Swaay Martin Warren 《Journal of Insect Conservation》2013,17(5):941-947
The Macedonian Grayling is listed as critically endangered in the recent IUCN Red List of European butterflies because of its extreme rarity and habitat loss due to quarrying. This categorisation was, however, based on rather limited knowledge on its actual distribution, population size and habitat requirements. In 2012, we conducted field surveys to acquire more information. We found the species at six new sites extending its known range of suitable habitat to just under 10 km2. The daily population size was estimated using capture-mark-recapture method in the most densely populated part of the Pletvar pass site at more than 650 individuals. Adults proved to be extremely sedentary, not moving far even within the continuous habitat on the same slope. Oviposition was observed on dry plant material and in a rock crevice close to the potential larval host plant Festuca sp. Quarrying is confirmed to be the main threat to the habitat of the Macedonian Grayling with five out of seven populated sites containing active marble quarries. Due to the enlargement of the known area of occupancy, its threat status would now be estimated at endangered. Despite the restricted knowledge about its distribution and trends in the population size, the IUCN criteria proved to be applicable to determine the threat status of a rare and localized butterfly such as Pseudochazara cingovskii. Its original assessment of being called the most threatened butterfly in Europe resulted in immediate research project and subsequent actions that will undoubtedly help to conserve it in the future. 相似文献
43.
Hua Wang Ping Zhao Dirk H lscher Quan Wang Ping Lu Xi A. Cai Xiao P. Zeng 《Journal of Plant Ecology》2012,5(3):294
Aims Nighttime sap flow of trees may indicate transpiration and/or recharge of stem water storage at night. This paper deals with the water use of Acacia mangium at night in the hilly lands of subtropical South China. Our primary goal was to reveal and understand the nature of nighttime sap flow and its functional significance.Methods Granier's thermal dissipation method was used to determine the nighttime sap flux of A. mangium. Gas exchange system was used to estimate nighttime leaf transpiration and stomatal conductance of studied trees.Important findings Nighttime sap flow was substantial and showed seasonal variation similar to the patterns of daytime sap flow in A. mangium. Mean nighttime sap flow was higher in the less precipitation year of 2004 (1122.4 mm) than in the more precipitation year of 2005 (1342.5 mm) since more daytime transpiration and low soil water availability in the relatively dry 2004 can be the cause of more nighttime sap flow. Although vapor pressure deficit and air temperature were significantly correlated with nighttime sap flow, they could only explain a small fraction of the variance in nighttime sap flow. The total accumulated water loss (E L) by transpiration of canopy leaves was only ~2.6–8.5% of the total nighttime sap flow (E t) during the nights of July 17–18 and 18–19, 2006. Therefore, it is likely that the nighttime sap flow was mainly used for refilling water in the trunk. The stem diameter at breast height, basal area and sapwood area explained much more variance of nighttime water recharge than environmental factors and other tree form features, such as tree height, stem length below the branch, and canopy size. The contribution of nighttime water recharge to the total transpiration ranged from 14.7 to 30.3% depending on different DBH class and was considerably higher in the dry season compared to the wet season. 相似文献
44.
Katleen Van Steendam Kelly Tilleman Marlies De Ceuleneer Filip De Keyser Dirk Elewaut Dieter Deforce 《Arthritis research & therapy》2010,12(4):R132
Introduction
Rheumatoid arthritis (RA) is an inflammatory disease, which results in destruction of the joint. The presence of immune complexes (IC) in serum and synovial fluid of RA patients might contribute to this articular damage through different mechanisms, such as complement activation. Therefore, identification of the antigens from these IC is important to gain more insight into the pathogenesis of RA. Since RA patients have antibodies against citrullinated proteins (ACPA) in their serum and synovial fluid (SF) and since elevated levels of citrullinated proteins are detected in the joints of RA patients, citrullinated antigens are possibly present in IC from RA patients. 相似文献45.
Cankar K van Houwelingen A Bosch D Sonke T Bouwmeester H Beekwilder J 《FEBS letters》2011,(1):3007-182
Chicory (Cichorium intybus L.), which is known to have a variety of terpene-hydroxylating activities, was screened for a P450 mono-oxygenase to convert (+)-valencene to (+)-nootkatone. A novel P450 cDNA was identified in a chicory root EST library. Co-expression of the enzyme with a valencene synthase in yeast, led to formation of trans-nootkatol, cis-nootkatol and (+)-nootkatone. The novel enzyme was also found to catalyse a three step conversion of germacrene A to germacra-1(10),4,11(13)-trien-12-oic acid, indicating its involvement in chicory sesquiterpene lactone biosynthesis. Likewise, amorpha-4,11-diene was converted to artemisinic acid. Surprisingly, the chicory P450 has a different regio-specificity on (+)-valencene compared to germacrene A and amorpha-4,11-diene. 相似文献
46.
Adam Dangoor Paul Lorigan Ulrich Keilholz Dirk Schadendorf Adrian Harris Christian Ottensmeier John Smyth Klaus Hoffmann Richard Anderson Martin Cripps Joerg Schneider Robert Hawkins 《Cancer immunology, immunotherapy : CII》2010,59(6):863-873
Background
Safety and cellular immunogenicity of rising doses and varying regimens of a poly-epitope vaccine were evaluated in advanced metastatic melanoma. The vaccine comprised plasmid DNA and recombinant modified vaccinia virus Ankara (MVA) both expressing a string (Mel3) of seven HLA.A2/A1 epitopes from five melanoma antigens.Methods
Forty-one HLA-A2 positive patients with stage III/IV melanoma were enrolled. Patient groups received one or two doses of DNA.Mel3 followed by escalating doses of MVA.Mel3. Immunisations then continued eight weekly in the absence of disease progression. Epitope-specific CD8+ T cell responses were evaluated using ex-vivo tetramer and IFN-γ ELISPOT assays. Safety and clinical responses were monitored.Results
Prime-boost DNA/MVA induced Melan-A-specific CD8+ T cell responses in 22/31 (71%) patients detected by tetramer assay. ELISPOT detected a response to at least one epitope in 10/31 (32%) patients. T cell responder rates were <50% with low-dose DNA/MVA, or MVA alone, rising to 91% with high-dose DNA/MVA. Among eight patients showing evidence of clinical benefit—one PR (24 months+), five SD (5 months+) and two mixed responses—seven had associated immune responses. Melan-A-tetramer+ immunity was associated with a median 8-week increase in time-to-progression (P = 0.037) and 71 week increase in survival (P = 0.0002) compared to non-immunity. High-dose vaccine was well tolerated. The only significant toxicities were flu-like symptoms and injection-site reactions.Conclusions
DNA.Mel3 and MVA.Mel3 in a prime-boost protocol generated high rates of immune response to melanoma antigen epitopes. The treatment was well tolerated and the correlation of immune responses with patient outcomes encourages further investigation. 相似文献47.
Christoph Syldatk Dirk Völkel Ulrich Bilitewski Karsten Krohn Hartmut Höke Fritz Wagner 《Biotechnology letters》1992,14(2):105-110
Summary Resting cells ofArthrobacter sp. (DSM 3745) with the ability to form L-tryptophan from D,L-5-(3-indolylmethy)hydantoin were used for the bioconversion of D,L-5-- and D,L-5--naphthylmethylhydantoin (D,L-5-- and D,L-5--NMH) to the corresponding L-amino acids. Under the optimal reaction conditions of pH 9.7 and 40°C specific productivities of 0.2 (-naphtylalanine) and 0.6 (-naphtylalanine) mM amino acid x g cell dry mass–1 x h–1 were obtained in a 0.1 M Na2CO3/NaHCO3-buffer in a strirred bioreactor. 相似文献
48.
Sang-Hoon Sin Sun Ah Kang Yongbaek Kim Anthony Eason Kelly Tan Hyowon An Dirk P. Dittmer 《Journal of virology》2016,90(4):2150-2154
Interleukin 6 (IL-6) is considered a proliferation and survival factor for B cells. To assess the role of IL-6 in Kaposi sarcoma-associated herpesvirus (KSHV) latency, KSHV latency locus-transgenic mice (referred to as latency mice) lacking IL-6 were evaluated. IL-6−/− latency mice had the same phenotypes as the latency mice, i.e., increased frequency of marginal zone B cells, hyperplasia, and hyperglobulinemia, indicating that the KSHV latency locus, which includes all viral microRNAs (miRNAs), can compensate for lack of IL-6 in premalignant B cell activation. 相似文献
49.
Fine mapping and imprinting analysis for fatness trait QTLs in pigs 总被引:10,自引:0,他引:10
Annemieke P. Rattink Dirk J. De Koning Marilyne Faivre Barbara Harlizius Johan A.M. van Arendonk Martien A.M. Groenen 《Mammalian genome》2000,11(8):656-661
Quantitative trait loci (QTL) for fatness traits were reported recently in an experimental Meishan × Large White and Landrace
F2 cross. To further investigate the regions on pig Chr 2 (SSC2), SSC4, and SSC7, 25 additional markers from these regions were
typed on 800 animals (619 F2 animals, their F1 parents, and F0 grandfathers). Compared with the published maps, a modified order of markers was observed for SSC4 and SSC7. QTL analyses
were performed both within the half-sib families as well as across families (line cross). Furthermore, a QTL model accounting
for imprinting effects was tested. Information content could be increased considerably on all three chromosomes. Evidence
for the backfat thickness QTL on SSC7 was increased, and the location could be reduced to a 33-cM confidence interval. The
QTL for intramuscular fat on SSC4 could not be detected in this half-sib analysis, whereas under the line cross model a suggestive
QTL on a different position on SSC4 was detected. For SSC2, in the half-sib analysis, a suggestive QTL for backfat thickness
was detected with the best position at 26 cM. Imprinting analysis, however, revealed a genome-wise, significant, paternally
expressed QTL on SSC2 with the best position at 63 cM. Our results suggest that this QTL is different from the previously
reported paternally expressed QTL for muscle mass and fat deposition on the distal tip of SSC2p.
Received: 15 October 1999 / Accepted: 21 February 2000 相似文献
50.
Identification and Application of Plasmids Suitable for Transfer of Foreign DNA to Members of the Genus Gordonia 下载免费PDF全文
Matthias Arensktter Dirk Baumeister Rainer Kalscheuer Alexander Steinbüchel 《Applied microbiology》2003,69(8):4971-4974
Gene transfer systems for Gordonia polyisoprenivorans strains VH2 and Y2K based on electroporation and conjugation, respectively, were established. Several parameters were optimized, resulting in transformation efficiencies of >4 × 105 CFU/μg of plasmid DNA. In contrast to most previously described electroporation protocols, the highest efficiencies were obtained by applying a heat shock after the intrinsic electroporation. Under these conditions, transfer and autonomous replication of plasmid pNC9503 was also demonstrated to proceed in G. alkanivorans DSM44187, G. nitida DSM44499T, G. rubropertincta DSM43197T, G. rubropertincta DSM46038, and G. terrae DSM43249T. Conjugational plasmid DNA transfer to G. polyisoprenivorans resulted in transfer frequencies of up to 5 × 10−6 of the recipient cells. Recombinant strains capable of polyhydroxyalkanoate synthesis from alkanes were constructed. 相似文献