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61.
P2X receptor (P2XR) is a family of the ATP-gated ion channel family and can permeabilize the plasma membrane to small cations
such as potassium, sodium, and calcium, resulting in cellular depolarization. There are seven P2XR that have been described
and cloned, with 45% identity in amino acid sequence. Each P2X receptors has two transmembrane domains that are separated
by an extracellular loop and an intracellular N and C terminus. Unlike the other P2X receptors, the P2X7R has a larger C terminus
with an extra 200 amino acid residues compared with the other receptors. The C terminus of the P2X7R has been implicated in
regulating receptor function including signaling pathway activation, cellular localization, protein–protein interactions,
and post-translational modification (PTM). In the present review, we discuss the role of the P2X7R C terminus in regards to
receptor function, describe the specific domains and motifs found therein and compare the C terminus sequence with others
proteins to discover predicted domains or sites of PTM. 相似文献
62.
63.
Francisco M. Padilla Juan de Dios Miranda Francisco I. Pugnaire 《Plant and Soil》2007,295(1-2):103-113
Using a 141 F2 population generated from maize inbred B64 × teosinte Zea nicaraguensis cross, quantitative trait loci (QTLs) controlling aerenchyma formation in roots under non-flooding drained soil conditions
were identified. Seedlings of Z. nicaraguensis formed clear aerenchyma in the cortex of adventitious roots in non-flooding conditions, whereas the maize inbred line B64
did not. In the F2 population, the capacity to develop aerenchyma exhibited wide and continuous variation, suggesting the trait was controlled
by multiple genes. A linkage map was developed using 85 SSR markers, covering 1,224 cM across all ten chromosomes. Composite
interval mapping analysis revealed that four QTLs for aerenchyma formation under non-flooding conditions were located to two
regions of chromosome 1 (identified as Qaer1.02-3 and Qaer1.07), chromosome 5 (Qaer5.09) and chromosome 8 (Qaer8.06-7), and these explained 46.5% of the total phenotypic variance. The multiple interval mapping approach identified additional
QTLs on chromosomes 1 (Qaer1.01) and 5 (Qaer5.01). Using these results, it may be possible to use SSR markers linked to aerenchyma formation in a marker assisted selection
approach to introduce aerenchyma formation in drained soil conditions into maize for the eventual development of flooding
tolerant maize hybrids. 相似文献
64.
Costa-Neto CM Parreiras-E-Silva LT Ruller R Oliveira EB Miranda A Oliveira L Ward RJ 《Biochemical and biophysical research communications》2006,347(3):634-640
The eukaryotic translation initiation factor 5A (eIF5A) is a protein ubiquitously present in archaea and eukarya, which undergoes a unique two-step post-translational modification called hypusination. Several studies have shown that hypusination is essential for a variety of functional roles for eIF5A, including cell proliferation and synthesis of proteins involved in cell cycle control. Up to now neither a totally selective inhibitor of hypusination nor an inhibitor capable of directly binding to eIF5A has been reported in the literature. The discovery of such an inhibitor might be achieved by computer-aided drug design based on the 3D structure of the human eIF5A. In this study, we present a molecular model for the human eIF5A protein based on the crystal structure of the eIF5A from Leishmania brasiliensis, and compare the modeled conformation of the loop bearing the hypusination site with circular dichroism data obtained with a synthetic peptide of this loop. Furthermore, analysis of amino acid variability between different human eIF5A isoforms revealed peculiar structural characteristics that are of functional relevance. 相似文献
65.
Donzelli S Espey MG Thomas DD Mancardi D Tocchetti CG Ridnour LA Paolocci N King SB Miranda KM Lazzarino G Fukuto JM Wink DA 《Free radical biology & medicine》2006,40(6):1056-1066
Nitroxyl (HNO) exhibits unique pharmacological properties that often oppose those of nitric oxide (NO), in part due to differences in reactivity toward thiols. Prior investigations suggested that the end products arising from the association of HNO with thiols were condition-dependent, but were inconclusive as to product identity. We therefore used HPLC techniques to examine the chemistry of HNO with glutathione (GSH) in detail. Under biological conditions, exposure to HNO donors converted GSH to both the sulfinamide [GSONH2] and the oxidized thiol (GSSG). Higher thiol concentrations generally favored a higher GSSG ratio, suggesting that the products resulted from competitive consumption of a single intermediate (GSNHOH). Formation of GSONH2 was not observed with other nitrogen oxides (NO, N2O3, NO2, or ONOO(-)),indicating that it is a unique product of the reaction of HNO with thiols. The HPLC assay was able to detect submicromolar concentrations of GSONH2. Detection of GSONH2 was then used as a marker for HNO production from several proposed biological pathways, including thiol-mediated decomposition of S-nitrosothiols and peroxidase-driven oxidation of hydroxylamine (an end product of the reaction between GSH and HNO) and NG-hydroxy-l-arginine (an NO synthase intermediate). These data indicate that free HNO can be biosynthesized and thus may function as an endogenous signaling agent that is regulated by GSH content. 相似文献
66.
Autoradiographic studies were carried out on regenerating muscles of adult chickens. Three different muscles of hens were injured, and tritiated thymidine (1 μCi/g) was injected at various times after injury to label replicating muscle precursors. Detailed comparisons of grain counts over premitotic nuclei in samples removed one hour after injection of tritiated thymidine, and of postmitotic myotube nuclei in samples removed 10 days after injury (when labeled precursors had fused to form myotubes), revealed how many times some labeled precursors had divided before fusing into myotubes. DNA synthesis in muscle precursors was initiated 30 h after injury. Grain counts of myotube nuclei indicated that many muscle precursors labeled at the onset of myogenic cell proliferation had divided only once, or twice, before fusing into myotubes. The relationship of these in vivo results to the cell lineage model of myogenesis is discussed. 相似文献
67.
Glutathione S-transferases (GSTs: EC2.5.1.18) are a superfamily of multifunctional dimeric enzymes that catalyze the conjugation of glutathione (GSH) to electrophilic chemicals. In most animals and in humans, GSTs are the principal enzymes responsible for detoxifying the mycotoxin aflatoxin B1 (AFB1) and GST dysfunction is a known risk factor for susceptibility towards AFB1. Turkeys are one of the most susceptible animals known to AFB1, which is a common contaminant of poultry feeds. The extreme susceptibility of turkeys is associated with hepatic GSTs unable to detoxify the highly reactive and electrophilic metabolite exo-AFB1-8,9-epoxide (AFBO). In this study, comparative genomic approaches were used to amplify and identify the α-class tGST genes (tGSTA1.1, tGSTA1.2, tGSTA1.3, tGSTA2, tGSTA3 and tGSTA4) from turkey liver. The conserved GST domains and four α-class signature motifs in turkey GSTs (with the exception of tGSTA1.1 which lacked one motif) confirm the presence of hepatic α-class GSTs in the turkey. Four signature motifs and conserved residues found in α-class tGSTs are (1) xMExxxWLLAAAGVE, (2) YGKDxKERAxIDMYVxG, (3) PVxEKVLKxHGxxxL and (4) PxIKKFLXPGSxxKPxxx. A BAC clone containing the α-class GST gene cluster was isolated and sequenced. The turkey α-class GTS genes genetically map to chromosome MGA2 with synteny between turkey and human α-class GSTs and flanking genes. This study identifies the α-class tGST gene cluster and genetic markers (SNPs, single nucleotide polymorphisms) that can be used to further examine AFB1 susceptibility and resistance in turkeys. Functional characterization of heterologously expressed proteins from these genes is currently underway. 相似文献
68.
Adenovirus-mediated hepatic overexpression of scavenger receptor class B type I accelerates chylomicron metabolism in C57BL/6J mice 总被引:3,自引:0,他引:3
Out R Hoekstra M de Jager SC de Vos P van der Westhuyzen DR Webb NR Van Eck M Biessen EA Van Berkel TJ 《Journal of lipid research》2005,46(6):1172-1181
The function of scavenger receptor class B type I (SR-BI) in mediating the selective uptake of HDL cholesteryl esters is well established. In SR-BI-deficient mice, we recently observed a delayed postprandial triglyceride (TG) response, suggesting an additional role for SR-BI in facilitating chylomicron (CM) metabolism. Here, we assessed the effect of adenovirus-mediated hepatic overexpression of SR-BI (Ad.SR-BI) in C57BL/6J mice on serum lipids and CM metabolism. Infection of 5 x 10(8) plaque-forming units per mouse of Ad.SR-BI significantly decreases serum cholesterol (>90%), phospholipids (>90%), and TG levels (50%), accompanied by a 41.4% reduction (P < 0.01) in apolipoprotein B-100 levels. The postprandial TG response is 2-fold lower in mice treated with Ad.SR-BI compared with control mice (area under the curve = 31.4 +/- 2.4 versus 17.7 +/- 3.2; P < 0.05). Hepatic mRNA expression levels of genes known to be involved in serum cholesterol and TG clearance are unchanged and thus could not account for the decreased plasma TG levels and the change in postprandial response. We conclude that overexpression of SR-BI accelerates CM metabolism, possibly by mediating the initial capture of CM remnants by the liver, whereby the subsequent internalization can be exerted by additional receptor systems such as the LDL receptor (LDLr) and LDLr-related protein 1. 相似文献
69.
Larissa Arrais Guimaraes Ana Paula Zotta Mota Ana Claudia Guerra Araujo Lucio Flavio de Alencar Figueiredo Bruna Medeiros Pereira Mario Alfredo de Passos Saraiva Raquel Bispo Silva Etienne G. J. Danchin Patricia Messenberg Guimaraes Ana Cristina Miranda Brasileiro 《Plant molecular biology》2017,93(1-2):79-96
70.
R. D. Reeves A. J. M. Baker T. Becquer G. Echevarria Z. J. G. Miranda 《Plant and Soil》2007,293(1-2):107-119
Major collections of the ultramafic flora of Goiás, central Brazil, were made by Brooks and co-workers in 1988 and 1990. At
the time of reports on this material in 1990–1992 much of it had been identified only tentatively and incompletely, but the
area was clearly interesting for taxonomic and biogeochemical reasons. Further progress has been made but still only two-thirds
of the specimens are identified at the species level. Following a third collection in early 2005, we now have 800 specimens
from this area, with chemical analyses of all the plants and of more than 120 representative soil samples. New species have
been found, e.g., in Paspalum (Poaceae) and Pterolepis (Melastomataceae). There is a need for more taxonomic work in genera such as Cnidoscolus (Euphorbiaceae), Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and Vellozia (Velloziaceae). Ni hyperaccumulation (>1,000 mg/kg in dry plant matter) has now been found in a total of 79 specimens, representing
more than 30 different species. Notable Ni hyperaccumulators include Pfaffia sarcophylla (Amaranthaceae), species of Justicia, Lophostachys and Ruellia (Acanthaceae), Porophyllum (Asteraceae), several species of Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and a possibly new Cnidoscolus (Euphorbiaceae). Ni hyperaccumulation has not been found in plants of the outcrops of Morro Feio or Crominia-Mairipotaba;
it seems to be confined to the extensive layered ultramafics of Barro Alto and the Macedo-Niquelandia areas. The distribution
of Ni-values in the Brazilian plant collection is different from that found in the Mediterranean and California, where there
is a clear distinction between accumulator and non-accumulator plants: in Brazil the distribution is more continuous, and
median Ni concentrations are much greater. An ultramafic hill just north of Niquelandia deserves to be protected because of
the presence there of many of the hyperaccumulators and species probably endemic to the Goiás ultramafics. 相似文献