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101.
Robert O. Hughes John K. Walker D. Joseph Rogier Steve E. Heasley Rhadika M. Blevis-Bal Alan G. Benson E. Jon Jacobsen Jerry W. Cubbage Yvette M. Fobian Dafydd R. Owen John N. Freskos John M. Molyneaux David L. Brown Brad A. Acker Todd M. Maddux Mike B. Tollefson Joseph B. Moon Brent V. Mischke Jeanne M. Rumsey Yi Zheng Ying Yu 《Bioorganic & medicinal chemistry letters》2009,19(17):5209-5213
We describe efforts to improve the pharmacokinetic profile of the aminopyridopyrazinone class of PDE5 inhibitors. These efforts led to the discovery of 3-[(trans-4-hydroxycyclohexyl)amino]-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one, a potent and selective inhibitor of PDE5 with an excellent PK profile. 相似文献
102.
Quettier AL Bertrand C Habricot Y Miginiac E Agnes C Jeannette E Maldiney R 《The Plant journal : for cell and molecular biology》2006,47(5):711-719
The plant hormone abscisic acid (ABA) controls numerous physiological traits: dormancy and germination of seeds, senescence and resistance to abiotic stresses. In order to get more insight into the role of protein tyrosine phosphatase (PTP) in ABA signalling, we obtained eight homozygous T-DNA insertion lines in Arabidopsis thaliana PTP genes. One mutant, named phs1-3, exhibited a strong ABA-induced inhibition of germination as only 26% of its seeds germinated after 3 days instead of 92% for the Columbia (Col-0) line. Genetic and molecular analyses of phs1-3 showed that it bears a unique T-DNA insertion in the promoter of the gene and that the mutation is recessive. PHS1 expression in the mutant is about half that of the Col-0 line. The upregulation of two ABA-induced genes (At5g06760, RAB18) and the downregulation of two ABA-repressed genes (AtCLC-A, ACL) are enhanced in the phs1-3 mutant compared with the wild-type. The 'in planta' aperture of phs1-3 stomata is reduced and the inhibition of the light-induced opening of stomata by ABA is stronger in phs1-3 leaves than in Col-0 leaves. Finally, PHS1 expression is upregulated in the presence of ABA in both phs1-3 and Col-0 but more intensively in the mutant. Thus, phs1-3 is hypersensitive to ABA. Taken together, these results show that PHS1, which encodes a dual-specificity PTP, is a negative regulator of ABA signalling. 相似文献
103.
Manjasetty BA Büssow K Fieber-Erdmann M Roske Y Gobom J Scheich C Götz F Niesen FH Heinemann U 《Protein science : a publication of the Protein Society》2006,15(4):914-920
The human protein PTD012 is the longer product of an alternatively spliced gene and was described to be localized in the nucleus. The X-ray structure analysis at 1.7 A resolution of PTD012 through SAD phasing reveals a monomeric protein and a novel fold. The shorter splice form was also studied and appears to be unfolded and non-functional. The structure of PTD012 displays an alphabetabetaalpha four-layer topology. A metal ion residing between the central beta-sheets is partially coordinated by three histidine residues. X-ray absorption near-edge structure (XANES) analysis identifies the PTD012-bound ion as Zn(2+). Tetrahedral coordination of the ion is completed by the carboxylate oxygen atom of an acetate molecule taken up from the crystallization buffer. The binding of Zn(2+) to PTD012 is reminiscent of zinc-containing enzymes such as carboxypeptidase, carbonic anhydrase, and beta-lactamase. Biochemical assays failed to demonstrate any of these enzyme activities in PTD012. However, PTD012 exhibits ester hydrolase activity on the substrate p-nitrophenyl acetate. 相似文献
104.
The transport protein particle (TRAPP) complexes are involved in the tethering process at different trafficking steps of vesicle transport. We here present the crystal structure of a human Bet3-Tpc6B heterodimer, which represents a core sub-complex in the assembly of TRAPP. We describe a conserved patch of Tpc6 with uncharged pockets, forming a putative interaction interface for an anchoring moiety at the Golgi. The structural and functional comparison of the two paralogs Tpc6A and Tpc6B, only found in some organisms, indicates redundancy and added complexity of TRAPP architecture and function. Both iso-complexes, Bet3-Tpc6A and Bet3-Tpc6B, are able to recruit Mum2, a further TRAPP subunit, and we identify the alpha1-alpha2 loop regions as a binding site for Mum2. Our study reveals similar stability of the iso-complexes and similar expression patterns of the tpc6 variants in different mouse organs. These findings raise the possibility that the Tpc6 paralogs might contribute to the formation of two distinct TRAPP complexes that differ in function. 相似文献
105.
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107.
Cooper M La Duc MT Probst A Vaishampayan P Stam C Benardini JN Piceno YM Andersen GL Venkateswaran K 《Applied and environmental microbiology》2011,77(15):5438-5444
A bacterial spore assay and a molecular DNA microarray method were compared for their ability to assess relative cleanliness in the context of bacterial abundance and diversity on spacecraft surfaces. Colony counts derived from the NASA standard spore assay were extremely low for spacecraft surfaces. However, the PhyloChip generation 3 (G3) DNA microarray resolved the genetic signatures of a highly diverse suite of microorganisms in the very same sample set. Samples completely devoid of cultivable spores were shown to harbor the DNA of more than 100 distinct microbial phylotypes. Furthermore, samples with higher numbers of cultivable spores did not necessarily give rise to a greater microbial diversity upon analysis with the DNA microarray. The findings of this study clearly demonstrated that there is not a statistically significant correlation between the cultivable spore counts obtained from a sample and the degree of bacterial diversity present. Based on these results, it can be stated that validated state-of-the-art molecular techniques, such as DNA microarrays, can be utilized in parallel with classical culture-based methods to further describe the cleanliness of spacecraft surfaces. 相似文献
108.
Coulson-Thomas VJ Coulson-Thomas YM Gesteira TF de Paula CA Mader AM Waisberg J Pinhal MA Friedl A Toma L Nader HB 《Cell and tissue research》2011,346(2):223-236
During cancer cell growth many tumors exhibit various grades of desmoplasia, unorganized production of fibrous or connective
tissue, composed mainly of collagen fibers and myofibroblasts. The accumulation of an extracellular matrix (ECM) surrounding
tumors directly affects cancer cell proliferation, migration and spread; therefore the study of desmoplasia is of vital importance.
Stromal fibroblasts surrounding tumors are activated to myofibroblasts and become the primary producers of ECM during desmoplasia.
The composition, density and organization of this ECM accumulation play a major role on the influence desmoplasia has upon
tumor cells. In this study, we analyzed desmoplasia in vivo in human colorectal carcinoma tissue, detecting an up-regulation of collagen I, collagen IV and collagen V in human colorectal
cancer desmoplastic reaction. These components were then analyzed in vitro co-cultivating colorectal cancer cells (Caco-2 and HCT116) and fibroblasts utilizing various co-culture techniques. Our findings
demonstrate that direct cell-cell contact between fibroblasts and colorectal cancer cells evokes an increase in ECM density,
composed of unorganized collagens (I, III, IV and V) and proteoglycans (biglycan, fibromodulin, perlecan and versican). The
desmoplastic collagen fibers were thick, with an altered orientation, as well as deposited as bundles. This increased ECM
density inhibited the migration and invasion of the colorectal tumor cells in both 2D and 3D co-culture systems. Therefore
this study sheds light on a possible restricting role desmoplasia could play in colorectal cancer invasion. 相似文献
109.
Weinert N Piceno Y Ding GC Meincke R Heuer H Berg G Schloter M Andersen G Smalla K 《FEMS microbiology ecology》2011,75(3):497-506
The phylogenetic composition of bacterial communities in the rhizosphere of three potato cultivars grown at two distant field sites was analysed. Ribosomal gene fragments amplified from total community DNA were hybridized to PhyloChips. A total of 2432 operational taxonomic units (OTUs) were detected by the PhyloChips, of which 65% were found in the rhizosphere of all cultivars at both field sites. From all detected OTUs, 9% revealed a cultivar-dependent abundance at the one or the other field site and 4% at both sites. Differential abundance on the three cultivars was mainly observed for OTUs belonging to the Pseudomonadales, Actinomycetales and Enterobacteriales. More than 40% of OTUs belonging to Bradyrhizobiales, Sphingomonadales, Burkholderiales, Rhodocyclales, Xanthomonadales and Actinomycetales differed significantly in their abundance between the sites. A sequence analysis of six 16S rRNA gene clone libraries corresponded well with the taxonomic community structure evidenced by the PhyloChip hybridization. Most ribotypes matched OTUs detected by the PhyloChip. Those OTUs that responded to the potato cultivar at both field sites might be of interest in view of cultivar-specific effects on bacterial biocontrol strains and pathogens. 相似文献