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121.
Diversity of the abundant pKLC102/PAGI-2 family of genomic islands in Pseudomonas aeruginosa 下载免费PDF全文
Klockgether J Würdemann D Reva O Wiehlmann L Tümmler B 《Journal of bacteriology》2007,189(6):2443-2459
The known genomic islands of Pseudomonas aeruginosa clone C strains are integrated into tRNA(Lys) (pKLC102) or tRNA(Gly) (PAGI-2 and PAGI-3) genes and differ from their core genomes by distinctive tetranucleotide usage patterns. pKLC102 and the related island PAPI-1 from P. aeruginosa PA14 were spontaneously mobilized from their host chromosomes at frequencies of 10% and 0.3%, making pKLC102 the most mobile genomic island known with a copy number of 30 episomal circular pKLC102 molecules per cell. The incidence of islands of the pKLC102/PAGI-2 type was investigated in 71 unrelated P. aeruginosa strains from diverse habitats and geographic origins. pKLC102- and PAGI-2-like islands were identified in 50 and 31 strains, respectively, and 15 and 10 subtypes were differentiated by hybridization on pKLC102 and PAGI-2 macroarrays. The diversity of PAGI-2-type islands was mainly caused by one large block of strain-specific genes, whereas the diversity of pKLC102-type islands was primarily generated by subtype-specific combination of gene cassettes. Chromosomal loss of PAGI-2 could be documented in sequential P. aeruginosa isolates from individuals with cystic fibrosis. PAGI-2 was present in most tested Cupriavidus metallidurans and Cupriavidus campinensis isolates from polluted environments, demonstrating the spread of PAGI-2 across habitats and species barriers. The pKLC102/PAGI-2 family is prevalent in numerous beta- and gammaproteobacteria and is characterized by high asymmetry of the cDNA strands. This evolutionarily ancient family of genomic islands retained its oligonucleotide signature during horizontal spread within and among taxa. 相似文献
122.
Nina Cramer Lutz Wiehlmann Oana Ciofu Stephanie Tamm Niels H?iby Burkhard Tümmler 《PloS one》2012,7(11)
Background/Methods
The molecular epidemiology of the chronic airway infections with Pseudomonas aeruginosa in individuals with cystic fibrosis (CF) was investigated by cross-sectional analysis of bacterial isolates from 51 CF centers and by longitudinal analysis of serial isolates which had been collected at the CF centers Hanover and Copenhagen since the onset of airway colonization over 30 years.Results
Genotyping revealed that the P. aeruginosa population in CF is dominated by a few ubiquitous clones. The five most common clones retrieved from the CF host also belonged to the twenty most frequent clones in the environment and in other human disease habitats. Turnover of clones in CF airways was rare. At the Hanover clinic more than half of the patient cohort was still harbouring the initially acquired clone after twenty years of airway colonization. At the Copenhagen clinic, however, two rare clones replaced the initially acquired individual clones in all but one patient.Conclusion
The divergent epidemiology at the two sites is explained by their differential management of hygiene and antipseudomonal chemotherapy. Hygienic measures to prohibit patient-to-patient transmission and the modalities of antipseudomonal chemotherapy modify the epidemiology of the chronic P. aeruginosa infections in CF. 相似文献123.
Trade‐Off between Trap Filling,Trap Creation,and Charge Recombination Results in Performance Increase at Ultralow Doping Levels in Bulk Heterojunction Solar Cells 下载免费PDF全文
Zhengrong Shang Thomas Heumueller Rohit Prasanna George F. Burkhard Benjamin D. Naab Zhenan Bao Michael D. McGehee Alberto Salleo 《Liver Transplantation》2016,6(24)
Doping of organic bulk heterojunction solar cells has the potential to improve their power conversion efficiency (PCE). Deconvoluting the effect of doping on charge transport, recombination, and energetic disorder remains challenging. It is demonstrated that molecular doping has two competing effects: on one hand, dopant ions create additional traps while on the other hand free dopant‐induced charges fill deep states possibly leading to V OC and mobility increases. It is shown that molar dopant concentrations as low as a few parts per million can improve the PCE of organic bulk heterojunctions. Higher concentrations degrade the performance of the cells. In doped cells where PCE is observed to increase, such improvement cannot be attributed to better charge transport. Instead, the V OC increase in unannealed P3HT:PCBM cells upon doping is indeed due to trap filling, while for annealed P3HT:PCBM cells the change in V OC is related to morphology changes and dopant segregation. In PCDTBT:PC70BM cells, the enhanced PCE upon doping is explained by changes in the thickness of the active layer. This study highlights the complexity of bulk doping in organic solar cells due to the generally low doping efficiency and the constraint on doping concentrations to avoid carrier recombination and adverse morphology changes. 相似文献
124.
Granum S Andersen TC Sørlie M Jørgensen M Koll L Berge T Lea T Fleckenstein B Spurkland A Sundvold-Gjerstad V 《The Journal of biological chemistry》2008,283(32):21909-21919
T cell-specific adapter protein (TSAd), encoded by the SH2D2A gene, interacts with Lck through its C terminus and thus modulates Lck activity. Here we mapped Lck phosphorylation and interaction sites on TSAd and evaluated their functional importance. The three C-terminal TSAd tyrosines Tyr(280), Tyr(290), and Tyr(305) were phosphorylated by Lck and functioned as docking sites for the Lck Src homology 2 (SH2) domain. Binding affinities of the TSAd Tyr(P)(280) and Tyr(P)(290) phosphopeptides to the isolated Lck SH2 domain were similar to that observed for the Lck Tyr(P)(505) phosphopeptide, whereas the TSAd Tyr(P)(305) peptide displayed a 10-fold higher affinity. The proline-rich Lck SH3-binding site on TSAd as well as the Lck SH2 domain were required for efficient tyrosine phosphorylation of TSAd by Lck. Interaction sites on TSAd for both Lck SH2 and Lck SH3 were necessary for TSAd-mediated modulation of proximal TCR signaling events. We found that 20-30% of TSAd molecules are phosphorylated in activated T cells and that the proportion of TSAd to Lck molecules in such cells is approximately 1:1. Therefore, in activated T cells, a considerable number of Lck molecules may potentially be engaged by TSAd. In conclusion, Lck binds to TSAd prolines and phosphorylates and interacts with the three C-terminal TSAd tyrosines. We propose that through multivalent interactions with Lck, TSAd diverts Lck from phosphorylating other substrates, thus modulating its functional activity through substrate competition. 相似文献
125.
Coiled coils: a highly versatile protein folding motif 总被引:31,自引:0,他引:31
The alpha-helical coiled coil is one of the principal subunit oligomerization motifs in proteins. Its most characteristic feature is a heptad repeat pattern of primarily apolar residues that constitute the oligomer interface. Despite its simplicity, it is a highly versatile folding motif: coiled-coil-containing proteins exhibit a broad range of different functions related to the specific 'design' of their coiled-coil domains. The architecture of a particular coiled-coil domain determines its oligomerization state, rigidity and ability to function as a molecular recognition system. Much progress has been made towards understanding the factors that determine coiled-coil formation and stability. Here we discuss this highly versatile protein folding and oligomerization motif with regard to its structural architecture and how this is related to its biological functions. 相似文献
126.
We here describe that soluble HLA-DQ2 (sDQ2) molecules, when expressed in Drosophila melanogaster S2 insect cells without a covalently tethered peptide, associate tightly with the D. melanogaster calcium binding protein DCB-45. The interaction between the proteins is stable in S2 cell culture and during affinity purification,
which is done at high salt concentrations and pH 11.5. After affinity purification, the sDQ2/DCB-45 complex exists in substantial
quantities next to a small amount of free heterodimeric sDQ2 and large amounts of aggregated sDQ2 free of DCB-45. Motivated
by the stable complex formation and our interest in the development of reagents which inhibit HLA-DQ2 peptide binding, we
have further characterized the sDQ2/DCB-45 interaction. Several lines of evidence indicate that an N-terminal fragment of
DCB-45 is involved in the interaction with the peptide binding groove of sDQ2. Further mapping of this fragment of 54 residues
identified a pentadecapeptide with high affinity for sDQ2 which may serve as a lead compound for the design of HLA-DQ2 blockers. 相似文献
127.
Abstract The genome of Pseudomonas aeruginosa was analysed by digestion with rare-cutting restriction endonucleases and subsequent field inversion gel electrophoresis (FIGE). P. aeruginosa strain PAO and the 17 IATS strains were investigated. Each strain displayed a unique pattern of restriction fragments. Digestion with Dra I and Ssp I yielded, respectively 7–11 and 2–5 fragments of more than 130 kb in size, indicating the non-random occurrence of AT-rich sequences in the P. aeruginosa genome. The genome size of P. aeruginosa PAO was estimated to be (2.2 ± 0.3) × 106 bp. The applications of DNA fingerprinting for gene cloning, construction of a physical chromosome map, and epidemiological studies, are discussed. 相似文献
128.
Frequent genes in rare diseases: panel‐based next generation sequencing to disclose causal mutations in hereditary neuropathies 下载免费PDF全文
Maike F. Dohrn Nicola Glöckle Lejla Mulahasanovic Corina Heller Julia Mohr Christine Bauer Erik Riesch Andrea Becker Florian Battke Konstanze Hörtnagel Thorsten Hornemann Saranya Suriyanarayanan Markus Blankenburg Jörg B. Schulz Kristl G. Claeys Burkhard Gess Istvan Katona Andreas Ferbert Debora Vittore Alexander Grimm Stefan Wolking Ludger Schöls Holger Lerche G. Christoph Korenke Dirk Fischer Bertold Schrank Urania Kotzaeridou Gerhard Kurlemann Bianca Dräger Anja Schirmacher Peter Young Beate Schlotter‐Weigel Saskia Biskup 《Journal of neurochemistry》2017,143(5):507-522
129.
Human TH17 lymphocytes promote blood-brain barrier disruption and central nervous system inflammation 总被引:23,自引:0,他引:23
Kebir H Kreymborg K Ifergan I Dodelet-Devillers A Cayrol R Bernard M Giuliani F Arbour N Becher B Prat A 《Nature medicine》2007,13(10):1173-1175
T(H)17 lymphocytes appear to be essential in the pathogenesis of numerous inflammatory diseases. We demonstrate here the expression of IL-17 and IL-22 receptors on blood-brain barrier endothelial cells (BBB-ECs) in multiple sclerosis lesions, and show that IL-17 and IL-22 disrupt BBB tight junctions in vitro and in vivo. Furthermore, T(H)17 lymphocytes transmigrate efficiently across BBB-ECs, highly express granzyme B, kill human neurons and promote central nervous system inflammation through CD4+ lymphocyte recruitment. 相似文献
130.
Amyloid fibrils associated with diseases such as Alzheimer's are often derived from the transmembrane helices of membrane proteins. It is known that the fibrils have a cross-beta-sheet structure where main chain hydrogen bonding occurs between beta-strands in the direction of the fibril axis. However, the structural basis for how the membrane-spanning helix is converted into a beta-sheet or how protofibrils associate into fibrils is not known. Here, we use a model peptide corresponding to a portion of the single transmembrane helix of glycophorin A to investigate the structural role of glycine in amyloid-like fibrils formed from transmembrane helices. Glycophorin A contains a GxxxG motif that is found in many transmembrane sequences including that of the amyloid precursor protein and prion protein. We propose that glycine, which mediates helix interactions in membrane proteins, also provides key packing motifs when it occurs in beta-sheets. We show that glycines in the glycophorin A transmembrane helix promote extended beta-strand formation when the helix partitions into aqueous environments and stabilize the packing of beta-sheets in the formation of amyloid-like fibrils. We demonstrate that fibrillization can be disrupted with a new class of inhibitors that target the molecular grooves created by glycine. 相似文献