21 research outputs found
Comparative study of morphological, cultural and molecular markers for the characterization of Pseudocercosporella herpotrichoides isolates
International audienc
Penta-hydroxyphenylpyruvate dioxygenase inhibitor-resistant plants
DOI:10.1002/ps.997International audienc
Berry n'est plus : stances / paroles de Mr Desaugiers ; musique de Mr F. Paër ; accompagnement de guitare par Mlle A. Sailland
Subcellular localization and purification of a p-hydroxyphenylpyruvate dioxygenase from cultured carrot cells and characterization of the corresponding cDNA
International audienc
Subcellular localization and purification of a p-hydroxyphenylpyruvate dioxygenase from cultured carrot cells and characterization of the corresponding cDNA.
p-Hydroxyphenylpyruvate dioxygenase catalyses the transformation of p-hydroxyphenylpyruvate into homogentisate. In plants this enzyme has a crucial role because homogentisate is the aromatic precursor of all prenylquinones. Furthermore this enzyme was recently identified as the molecular target for new families of potent herbicides. In this study we examine precisely the localization of p-hydroxyphenylpyruvate dioxygenase activity within carrot cells. Our results provide evidence that, in cultured carrot cells, p-hydroxyphenylpyruvate dioxygenase is associated with the cytosol. Purification and SDS/PAGE analysis of this enzyme revealed that its activity is associated with a polypeptide of 45-46 kDa. This protein specifically cross-reacts with an antiserum raised against the p-hydroxyphenylpyruvate dioxygenase of Pseudomonas fluorescens. Gel-filtration chromatography indicates that the enzyme behaves as a homodimer. We also report the isolation and nucleotide sequence of a cDNA encoding a carrot p-hydroxyphenylpyruvate dioxygenase. The nucleotide sequence (1684 bp) encodes a protein of 442 amino acid residues with a molecular mass of 48094 Da and shows specific C-terminal regions of similarity with other p-hydroxyphenylpyruvate dioxygenases. This cDNA encodes a functional p-hydroxyphenylpyruvate dioxygenase, as evidenced by expression studies with transformed Escherichia coli cells. Comparison of the N-terminal sequence of the 45-46 kDa polypeptide purified from carrot cells with the deduced peptide sequence of the cDNA confirms that this polypeptide supports p-hydroxyphenylpyruvate dioxygenase activity. Immunodetection studies of the native enzyme in carrot cellular extracts reveal that N-terminal proteolysis occurs during the process of purification. This proteolysis explains the difference in molecular masses between the purified protein and the deduced polypeptide
Computer Study of Microstructure Formation by Rearrangement During Liquid Phase Sintering
AMINO ACID SEQUENCE ANALYSIS OF THE SMALL SUBUNIT OF RIBULOSE BISPHOSPHATE CARBOXYLASE FROM FUCUS (PHAEOPHYCEAE)
Synthèse 2. Architecture, modes d'exploitation forestière et croissance démographique
International audienc
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Losartan Rescues Inflammation-related Mucociliary Dysfunction in Relevant Models of Cystic Fibrosis
Despite therapeutic progress in treating cystic fibrosis (CF) airway disease, airway inflammation with associated mucociliary dysfunction remains largely unaddressed. Inflammation reduces the activity of apically expressed large-conductance Ca
-activated and voltage-dependent K
(BK) channels, critical for mucociliary function in the absence of CFTR (CF transmembrane conductance regulator).
To test losartan as an antiinflammatory therapy in CF using CF human bronchial epithelial cells and an ovine model of CF-like airway disease.
Losartan's antiinflammatory effectiveness to rescue BK activity and thus mucociliary function was tested
using primary, fully redifferentiated human airway epithelial cells homozygous for F508del and
using a previously validated, now expanded pharmacologic sheep model of CF-like, inflammation-associated mucociliary dysfunction.
Nasal scrapings from patients with CF showed that neutrophilic inflammation correlated with reduced expression of LRRC26 (leucine rich repeat containing 26), the γ subunit mandatory for BK function in the airways. TGF-β1 (transforming growth factor β1), downstream of neutrophil elastase, decreased mucociliary parameters
. These were rescued by losartan at concentrations achieved by nebulization in the airway and oral application in the bloodstream: BK dysfunction recovered acutely and over time (the latter via an increase in LRRC26 expression), ciliary beat frequency and airway surface liquid volume improved, and mucus hyperconcentration and cellular inflammation decreased. These effects did not depend on angiotensin receptor blockade. Expanding on a validated and published nongenetic, CF-like sheep model, ewes inhaled CFTR
172 and neutrophil elastase for 3 days, which resulted in prolonged tracheal mucus velocity reduction, mucus hyperconcentration, and increased TGF-β1. Nebulized losartan rescued both mucus transport and mucus hyperconcentration and reduced TGF-β1.
Losartan effectively reversed CF- and inflammation-associated mucociliary dysfunction, independent of its angiotensin receptor blockade