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121.
122.
Hetty C van den Broeck Teun WJM van Herpen Cees Schuit Elma MJ Salentijn Liesbeth Dekking Dirk Bosch Rob J Hamer Marinus JM Smulders Ludovicus JWJ Gilissen Ingrid M van der Meer 《BMC plant biology》2009,9(1):41
Background
Gluten proteins can induce celiac disease (CD) in genetically susceptible individuals. In CD patients gluten-derived peptides are presented to the immune system, which leads to a CD4+ T-cell mediated immune response and inflammation of the small intestine. However, not all gluten proteins contain T-cell stimulatory epitopes. Gluten proteins are encoded by multigene loci present on chromosomes 1 and 6 of the three different genomes of hexaploid bread wheat (Triticum aestivum) (AABBDD). 相似文献123.
N6‐methyladenine is the most widespread mRNA modification. A subset of human box C/D snoRNA species have target GAC sequences that lead to formation of N6‐methyladenine at a key trans Hoogsteen‐sugar A·G base pair, of which half are methylated in vivo. The GAC target is conserved only in those that are methylated. Methylation prevents binding of the 15.5‐kDa protein and the induced folding of the RNA. Thus, the assembly of the box C/D snoRNP could in principle be regulated by RNA methylation at its critical first stage. Crystallography reveals that N6‐methylation of adenine prevents the formation of trans Hoogsteen‐sugar A·G base pairs, explaining why the box C/D RNA cannot adopt its kinked conformation. More generally, our data indicate that sheared A·G base pairs (but not Watson–Crick base pairs) are more susceptible to disruption by N6mA methylation and are therefore possible regulatory sites. The human signal recognition particle RNA and many related Alu retrotransposon RNA species are also methylated at N6 of an adenine that forms a sheared base pair with guanine and mediates a key tertiary interaction. 相似文献
124.
L Vila V Lacadena P Fontanet A Martinez del Pozo B San Segundo 《Molecular plant-microbe interactions : MPMI》2001,14(11):1327-1331
A purified preparation of antifungal protein (AFP) from Aspergillus giganteus exhibited potent antifungal activity against the phytopathogenic fungi Magnaporthe grisea and Fusarium moniliforme, as well as the oomycete pathogen Phytophthora infestans. Under conditions of total inhibition of fungal growth, no toxicity of AFP toward rice protoplasts was observed. Additionally, application of AFP on rice plants completely inhibited M. grisea growth. These results are discussed in relation to the potential of the afp gene to enhance crop protection against fungal pathogens in transgenic plants. 相似文献
125.
Lajas AI Pozo MJ Camello PJ Salido GM Singh J Pariente JA 《Molecular and cellular biochemistry》2000,205(1-2):163-169
This study investigates the effects of dephostatin, a new tyrosine phosphatase inhibitor, on intracellular free calcium concentration ([Ca2+]i) and amylase secretion in collagenase dispersed rat pancreatic acinar cells. Dephostatin evoked a sustained elevation in [Ca2+]i by mobilizing calcium from intracellular calcium stores in either the absence of extracellular calcium or the presence of lanthanium chloride (LaCl3). Pretreatment of acinar cells with dephostatin prevented cholecystokinin-octapeptide (CCK-8)-induced signal of [Ca2+]i and inhibited the oscillatory pattern initiated by aluminium fluoride (AlF-
4), whereas co-incubation with CCK-8 enhances the plateau phase of calcium response to CCK-8 without modifying the transient calcium spike. The effects of dephostatin on calcium mobilization were reversed by the presence of the sulfhydryl reducing agent, dithiothreitol. Stimulation of acinar cells with thapsigargin in the absence of extracellular Ca2+ resulted in a transient rise in [Ca2+]i . Application of dephostatin in the continuous presence of thapsigargin caused a small but sustained elevation in [Ca2+]i . These results suggest that dephostatin can mobilize Ca2+ from both a thapsigargin-sensitive and thapsigargin-insensitive intracellular stores in pancreatic acinar cells. In addition, dephostatin can stimulate the release of amylase from pancreatic acinar cells and moreover, reduce the secretory response to CCK-8. The results indicate that dephostatin can release calcium from intracellular calcium pools and consequently induces amylase secretion in pancreatic acinar cells. These effects are likely due to the oxidizing effects of this compound. 相似文献
126.
Current phylogenetic tree reconstruction methods assume that there is a
single underlying tree topology for all sites along the sequence. The
presence of mosaic sequences due to recombination violates this assumption
and will cause phylogenetic methods to give misleading results due to the
imposition of a single tree topology on all sites. The detection of mosaic
sequences caused by recombination is therefore an important first step in
phylogenetic analysis. A graphical method for the detection of
recombination, based on the least squares method of phylogenetic
estimation, is presented here. This method locates putative recombination
breakpoints by moving a window along the sequence. The performance of the
method is assessed by simulation and by its application to a real data set.
相似文献
127.
Involvement of nitrogen and cytokinins in photosynthetic acclimation to elevated CO2 of spring wheat
Diego Gutiérrez Rosa Morcuende Alejandro Del Pozo Rafael Martínez-Carrasco Pilar Pérez 《Journal of plant physiology》2013
Acclimation of photosynthetic capacity to elevated CO2 involves a decrease of the leaf Rubisco content. In the present study, it was hypothesized that nitrogen uptake and partitioning within the leaf and among different aboveground organs affects the down-regulation of Rubisco. Given the interdependence of nitrogen and cytokinin signals at the whole plant level, it is also proposed that cytokinins affect the nitrogen economy of plants under elevated CO2, and therefore the acclimatory responses. Spring wheat received varying levels of nitrogen and cytokinin in field chambers with ambient (370 μmol mol−1) or elevated (700 μmol mol−1) atmospheric CO2. Gas exchange, Rubisco, soluble protein and nitrogen contents were determined in the top three leaves in the canopy, together with total nitrogen contents per shoot. Growth in elevated CO2 induced decreases in photosynthetic capacity only when nitrogen supply was low. However, the leaf contents of Rubisco, soluble protein and total nitrogen on an area basis declined in elevated CO2 regardless of nitrogen supply. Total nitrogen in the shoot was no lower in elevated than ambient CO2, but the fraction of this nitrogen located in flag and penultimate leaves was lower in elevated CO2. Decreased Rubisco: chlorophyll ratios accompanied losses of leaf Rubisco with CO2 enrichment. Cytokinin applications increased nitrogen content in all leaves and nitrogen allocation to senescing leaves, but decreased Rubisco contents in flag leaves at anthesis and in all leaves 20 days later, together with the amount of Rubisco relative to soluble protein in all leaves at both growth stages. The results suggest that down regulation of Rubisco in leaves at elevated CO2 is linked with decreased allocation of nitrogen to the younger leaves and that cytokinins cause a fractional decrease of Rubisco and therefore do not alleviate acclimation to elevated CO2. 相似文献
128.
Oscar J. Pozo Peter Van Eenoo Koen Deventer Leen Lootens Susana Grimalt Juan V. Sancho Felix Hernández Philip Meuleman Geert Leroux-Roels Frans T. Delbeke 《Steroids》2009,74(10-11):837-852
The applicability of LC–MS/MS in precursor ion scan mode for the detection of urinary stanozolol metabolites has been studied. The product ion at m/z 81 has been selected as specific for stanozolol metabolites without a modification in A- or N-rings and the product ions at m/z 97 and 145 for the metabolites hydroxylated in the N-ring and 4-hydroxy-stanozolol metabolites, respectively. Under these conditions, the parent drug and up to 15 metabolites were found in a positive doping test sample. The study of a sample from a chimeric uPA-SCID mouse collected after the administration of stanozolol revealed the presence of 4 additional metabolites. The information obtained from the product ion spectra was used to develop a SRM method for the detection of 19 compounds. This SRM method was applied to several doping positive samples. All the metabolites were detected in both the uPA-SCID mouse sample and positive human samples and were not detected in none of the blank samples tested; confirming the metabolic nature of all the detected compounds. In addition, the application of the SRM method to a single human excretion study revealed that one of the metabolites (4ξ,16ξ-dihydroxy-stanozolol) could be detected in negative ionization mode for a longer period than those commonly used in the screening for stanozolol misuse (3′-hydroxy-stanozolol, 16β-hydroxy-stanozolol and 4β-hydroxy-stanozolol) in doping analysis. The application of the developed approach to several positive doping samples confirmed the usefulness of this metabolite for the screening of stanozolol misuse. Finally, a tentative structure for each detected metabolite has been proposed based on the product ion spectra measured with accurate masses using UPLC–QTOF MS. 相似文献
129.
Disruption of the filamentous actin cytoskeleton is necessary for the activation of capacitative calcium entry in naive smooth muscle cells 总被引:3,自引:0,他引:3
It has been proposed that cytoskeleton plays a key positive role in the activation of capacitative calcium entry (CCE), which supported the secretion-like hypothesis for the mechanisms underlying this process. However, its role on CCE in native smooth muscle is unknown. Here we demonstrate that CCE in isolated gallbladder myocytes was enhanced by cytochalasin D or latrunculin A treatments (agents that cause actin disassembly) whereas it was reduced by jasplakinolide treatment (which causes actin polymerization), suggesting that actin cytoskeleton acts as a barrier in CCE. In addition, we show for the first time that depletion of intracellular Ca2+ stores by thapsigargin and cholecystokinin in BAPTA-loaded cells induced a decrease in F-actin content that was consistent with a link between CCE and actin reorganization. In conclusion, these data suggest an active participation of actin reorganization in the implementation of CCE and support a conformational coupling model for this process in naive smooth muscle cells. 相似文献
130.