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51.
Andreas Schmid Zoltan Sutto Nathalie Schmid Lisa Novak Pedro Ivonnet Gabor Horvath Gregory Conner Nevis Fregien Matthias Salathe 《The Journal of biological chemistry》2010,285(39):29998-30007
Human airway cilia contain soluble adenylyl cyclase (sAC) that produces cAMP upon HCO3−/CO2 stimulation to increase ciliary beat frequency (CBF). Because apical HCO3− exchange depends on cystic fibrosis transmembrane conductance regulator (CFTR), malfunctioning CFTR might impair sAC-mediated CBF regulation in cells from patients with cystic fibrosis (CF). By Western blot, sAC isoforms are equally expressed in normal and CF airway epithelial cells, but CBF decreased more in CF than normal cells upon increased apical HCO3−/CO2 exposure in part because of greater intracellular acidification from unbalanced CO2 influx (estimated by 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) fluorescence). Importantly, ciliated cell-specific cAMP production (estimated by FRET fluorescence ratio changes of tagged cAMP-dependent protein kinase (PKA) subunits expressed under a ciliated cell-specific promoter) in response to increased apical HCO3−/CO2 perfusion was higher in normal compared with CF cells. Inhibition of bicarbonate influx via CFTR (CFTRinh172) and inhibition of sAC (KH7) and PKA activation (H89) led to larger CBF declines in normal cells, now comparable with changes seen in CF cells. These inhibitors also reduced FRET changes in normal cells to the level of CF cells with the expected exception of H89, which does not prevent dissociation of the fluorescently tagged PKA subunits. Basolateral permeabilization and subsequent perfusion with HCO3−/CO2 rescued CBF and FRET changes in CF cells to the level of normal cells. These results suggest that CBF regulation by sAC-produced cAMP could be impaired in CF, thereby possibly contributing to mucociliary dysfunction in this disease, at least during disease exacerbations when airway acidification is common. 相似文献
52.
53.
Strategies to introduce genes into non-embryogenic plants for complementation of a mutation are described and tested on tetraploid alfalfa (Medicago sativa). Genes conditioning embryogenic potential, a mutant phenotype, and a gene to complement the mutation can be combined using several different crossing and selection steps. In the successful strategy used here, the M. sativa genotype MnNC-1008(NN) carrying the recessive non-nodulating mutant allele nn
1
was crossed with the highly embryogenic alfalfa line Regen S and embryogenic hybrid individuals were identified from the F1 progeny. After transformation of these hybrids with the wild-type gene (NORK), an F2 generation segregating for the mutation and transgene were produced. Plants homozygous for the mutant allele and carrying the wild-type NORK transgene could form root nodules after inoculation with Sinorhizobium meliloti demonstrating successful complementation of the nn
1
mutation. 相似文献
54.
55.
Reliability and reproducibility issues in DNA microarray measurements 总被引:22,自引:0,他引:22
56.
The dynamics of the microtubule cytoskeleton are controlled by microtubule-associated proteins (MAPs). In this issue, show that Mal3p, the yeast EB1 homolog, belongs to a new class of MAPs that "zipper" up the seam of the microtubule lattice. 相似文献
57.
Maliga Z Xing J Cheung H Juszczak LJ Friedman JM Rosenfeld SS 《The Journal of biological chemistry》2006,281(12):7977-7982
Monastrol is a small molecule inhibitor that is specific for Eg5, a member of the kinesin 5 family of mitotic motors. Crystallographic models of Eg5 in the presence and absence of monastrol revealed that drug binding produces a variety of structural changes in the motor, including in loop L5 and the neck linker. What is not clear from static crystallographic models, however, is the sequence of structural changes produced by drug binding. Furthermore, because crystallographic structures can be influenced by the packing forces in the crystal, it also remains unclear whether these drug-induced changes occur in solution, at physiologically active concentrations of monastrol or of other drugs that target this site. We have addressed these issues by using a series of spectroscopic probes to monitor the structural consequences of drug binding. Our results demonstrated that the crystallographic model of an Eg5-ADP-monastrol ternary complex is consistent with several solution-based spectroscopic probes. Furthermore, the kinetics of these spectroscopic signal changes allowed us to determine the temporal sequence of drug-induced structural transitions. These results suggested that L5 may be an element in the pathway that links the state of the nucleotide-binding site to the neck linker in kinesin motors. 相似文献
58.
Atanasova I Urshev Z Hristova P Bogatzevska N Moncheva P 《Zeitschrift für Naturforschung. C, Journal of biosciences》2012,67(3-4):187-194
The aim of this study was to characterize genetically Bulgarian Erwinia amylovora strains using pulsed-field gel electrophoresis (PFGE) analysis. Fifty E. amylovora strains isolated from different hosts, locations, as well as in different years were analysed by PFGE after XbaI, SpeI, and XhoI digestion of the genomic DNA. The strains were distributed into four groups according to their XbaI-generated profile. About 82% of the strains displayed a PFGE profile identical to that of type Pt2. Three strains belonged to the Central Europe Pt1 type. Two new PFGE profiles, not reported so far, were established--one for a strain isolated from Malus domestica and another for all Fragaria spp. strains. The same grouping of the strains was obtained after analysis of the SpeI digestion patterns. On the basis of PFGE profiles, after XbaI and SpeI digestion, a genetic differentiation between the strains associated with subfamily Maloideae and subfamily Rosoideae was revealed. The presence of more than one PFGE profile in the population of E. amylovora in Bulgaria suggests a multiple source of inoculum. 相似文献
59.
2-hydroxyglutarate detection by magnetic resonance spectroscopy in IDH-mutated patients with gliomas
Choi C Ganji SK DeBerardinis RJ Hatanpaa KJ Rakheja D Kovacs Z Yang XL Mashimo T Raisanen JM Marin-Valencia I Pascual JM Madden CJ Mickey BE Malloy CR Bachoo RM Maher EA 《Nature medicine》2012,18(4):624-629
Mutations in isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) have been shown to be present in most World Health Organization grade 2 and grade 3 gliomas in adults. These mutations are associated with the accumulation of 2-hydroxyglutarate (2HG) in the tumor. Here we report the noninvasive detection of 2HG by proton magnetic resonance spectroscopy (MRS). We developed and optimized the pulse sequence with numerical and phantom analyses for 2HG detection, and we estimated the concentrations of 2HG using spectral fitting in the tumors of 30 subjects. Detection of 2HG correlated with mutations in IDH1 or IDH2 and with increased levels of D-2HG by mass spectrometry of the resected tumors. Noninvasive detection of 2HG may prove to be a valuable diagnostic and prognostic biomarker. 相似文献
60.
CM Lange S Bibert Z Kutalik P Burgisser A Cerny JF Dufour A Geier TJ Gerlach MH Heim R Malinverni F Negro S Regenass K Badenhoop J Bojunga C Sarrazin S Zeuzem T Müller T Berg PY Bochud D Moradpour;Swiss Hepatitis C Cohort Study Group 《PloS one》2012,7(7):e40159