Rhône-Poulenc

About: Rhône-Poulenc is a based out in . It is known for research contribution in the topics: Alkyl & Catalysis. The organization has 8909 authors who have published 8934 publications receiving 182241 citations. The organization is also known as: Rhone-Poulenc.

Isolation and kinetic properties of acetohydroxy acid isomeroreductase from spinach (Spinacia oleracea) chloroplasts overexpressed in Escherichia coli.

Abstract: Acetohydroxy acid isomeroreductase catalyses a two-step reaction, an alkyl migration and a NADPH-dependent reduction, in the assembly of the carbon skeletons of branched-chain amino acids. Detailed investigations of acetohydroxy acid isomeroreductase aimed at elucidating the biosynthetic pathway of branched-chain amino acids and at designing new inhibitors of the enzyme having herbicidal potency have so far been conducted with the enzymes isolated from bacteria. To gain more information on a plant system, the gene encoding the mature acetohydroxy acid isomeroreductase from spinach (Spinacia oleracea) leaf chloroplasts has been used to transform Escherichia coli cells and to overexpress the enzyme. A rapid protocol is described that allows the preparation of large quantities of pure spinach chloroplast acetohydroxy acid isomeroreductase. Kinetic and structural properties of the plant enzyme expressed in Escherichia coli are compared with those reported in our previous studies on the native enzymes purified from spinach chloroplasts and with those reported for the corresponding enzymes isolated from Escherichia coli and Salmonella typhimurium. Both the plant and the bacterial enzymes obey an ordered mechanism in which NADPH binds first, followed by substrate (either 2-acetolactate or 2-aceto-2-hydroxybutyrate). Inhibition studies employing an inactive substrate analogue, 2-hydroxy-2-methyl-3-oxopentanoate, showed, however, that the binding of 2-hydroxy-2-methyl-3-oxopentanoate and NADPH occurs randomly, suggestive of some flexibility of the plant enzyme active site. The observed preference of the enzyme for 2-aceto-2-hydroxybutyrate over 2-acetolactate is discussed with regard to the contribution of acetohydroxy acid isomeroreductase activity in the partitioning between isoleucine and valine biosyntheses. Moreover, the kinetic properties of the chloroplast enzyme support the notion that biosynthesis of branched-chain amino acids in plants is controlled by light. As judged by analytical-ultracentrifugation and gel-filtration analyses the overexpressed plant enzyme is a dimer of identical subunits.

Synergistic termiticidal composition of pyrethroid and n-phenyl-pyrazole

Abstract: A termite control composition for soil treatment containing 3-cyano-1-(substituted phenyl) pyrazole derivative and a pyrethroid compound as effective ingredients, and a method of controlling pests such as termites using said composition. The termite control composition is improved for soil treatment as well as for the ability to prevent termites from passing through the pesticidally treated layer.

Novel farnesyl transferase inhibitors, preparation thereof and pharmaceutical compositions containing same

Abstract: Nouveaux inhibiteurs de farnesyl transferase de formule generale (I), leur preparation et les compositions pharmaceutiques qui les contiennent. New farnesyl transferase inhibitors of general formula (I), their preparation and pharmaceutical compositions containing them. Dans la formule generale (I), R1 represente YS-A1-(Y = atome d'hydrogene, reste d'aminoacide, reste d'acide gras, radical alkyle ou alcoxycarbonyle, et A1 = radical alcoylene contenant 1 a 4 atomes de carbone eventuellement substitue en a du groupement >=C(X1)(Y1) par un radical amino, alkylamino, alkanoylamino, alkoxycarbonylamino dont la partie alkyle ou alkanoyle contient 1 a 6 atomes de carbone, X1 et Y1 representent chacun un atome d'hydrogene ou forment ensemble avec l'atome de carbone auquel ils sont lies un groupement > C=O, R'1 represente hydrogene ou un radical alkyle contenant 1 a In the general formula (I), R1 represents YS-A1- (Y = hydrogen, amino acid residue, fatty acid radical, alkyl or alkoxycarbonyl radical, and A1 = alkylene radical containing 1 to 4 carbon atoms optionally substituted by a group of> = C (X1) (Y1) group by an amino, alkylamino, alkanoylamino, alkoxycarbonylamino, the alkyl or alkanoyl portion contains 1 to 6 carbon atoms, X1 and Y1 each represent a hydrogen atom or together with the carbon atom to which they are bonded, a> C = O, R'1 represents hydrogen or an alkyl radical containing 1 to 6 atomes de carbone, X represente un atome d'oxygene ou de soufre, R2 represente un radical alkyle, alcenyle ou alcynyle contenant 1 a 6 carbon atoms, X represents an oxygen or sulfur atom, R2 represents an alkyl, alkenyl or alkynyl group containing 1 to 6 atomes de carbone eventuellement substitue par hydroxy, alkoxy, mercapto, alkylthio, alkysulfinyle ou alkylsufonyle, etant entendu que, lorsque R2 represente un radical alkyle substitue par un radical hydroxy, R2 peut former avec le radical carboxy en .alpha. 6 carbon atoms optionally substituted by hydroxy, alkoxy, mercapto, alkylthio, or alkylsulfonyl alkysulfinyle, it being understood that when R 2 represents an alkyl radical substituted by a hydroxy radical, R2 can form the carboxy radical .alpha. une lactone, R'2 represente hydrogene ou un radical alkyle contenant 1 a 6 atomes de carbone, et R represente un atome d'hydrogene ou un radical alcoyle eventuellement substitue ou un radical phenyle eventuellement substitue. a lactone, R '2 represents hydrogen or an alkyl radical containing 1 to 6 carbon atoms, and R represents a hydrogen atom or an alkyl radical optionally substituted alkyl or optionally substituted phenyl radical. Ces nouveaux produits presentent des proprietes anticancereuses. These new products have anticancer properties.

Quinupristin-Dalfopristin Combined with β-Lactams for Treatment of Experimental Endocarditis Due to Staphylococcus aureus Constitutively Resistant to Macrolide-Lincosamide-Streptogramin B Antibiotics

Abstract: Quinupristin-dalfopristin (Q-D) is an injectable streptogramin active against most gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). In experimental endocarditis, however, Q-D was less efficacious against MRSA isolates constitutively resistant to macrolide-lincosamide-streptogram B (C-MLS B ) than against MLS B -susceptible isolates. To circumvent this problem, we used the checkerboard method to screen drug combinations that would increase the efficacy of Q-D against such bacteria. β-Lactams consistently exhibited additive or synergistic activity with Q-D. Glycopeptides, quinolones, and aminoglycosides were indifferent. No drugs were antagonistic. The positive Q-D–β-lactam interaction was independent of MLS B or β-lactam resistance. Moreover, addition of Q-D at one-fourth the MIC to flucloxacillin-containing plates decreased the flucloxacillin MIC for MRSA from 500 to 1,000 mg/liter to 30 to 60 mg/liter. Yet, Q-D–β-lactam combinations were not synergistic in bactericidal tests. Rats with aortic vegetations were infected with two C-MLS B -resistant MRSA isolates (isolates AW7 and P8) and were treated for 3 or 5 days with drug dosages simulating the following treatments in humans: (i) Q-D at 7 mg/kg two times a day (b.i.d.) (a relatively low dosage purposely used to help detect positive drug interactions), (ii) cefamandole at constant levels in serum of 30 mg/liter, (iii) cefepime at 2 g b.i.d., (iv) Q-D combined with either cefamandole or cefepime. Any of the drugs used alone resulted in treatment failure. In contrast, Q-D plus either cefamandole or cefepime significantly decreased valve infection compared to the levels of infection for both untreated controls and those that received monotherapy ( P

Phenylephrine protects neonatal rat cardiomyocytes from hypoxia and serum deprivation-induced apoptosis.

Abstract: Previous studies have shown that alpha-adrenergic activation reduces myocardial damages caused by ischemia/reperfusion. However, the molecular mechanisms of how alpha-adrenergic activation protects the myocardium are not completely understood. The objective of this study was to test the hypothesis that alpha-adrenergic activation protects the myocardium by, at least in part, inhibiting apoptosis in cardiomyocytes. The current data has shown that apoptosis in neonatal rat cardiomyocytes, induced by 24 h treatment with hypoxia (95% N2 and 5% CO2) and serum deprivation, was inhibited by co-treatment with phenylephrine. Pre-treatment with phenylephrine for 24 h also protected cardiomyocytes against subsequent 24 h treatment with hypoxia and serum deprivation. Exposure of cardiomyocytes to phenylephrine for up to 9 days under normoxic conditions did not cause apoptosis. The phenylephrine-mediated cytoprotection was blocked by an alpha-adrenergic antagonist, phentolamine. beta-adrenergic activation with isoproterenol did not protect cardiomyocytes against hypoxia and serum deprivation-induced apoptosis. Under hypoxic conditions, phenylephrine prevented the down-regulation of Bcl-2 and Bcl-X mRNA/protein and induced hypertrophic growth. Phenylephrine-mediated protection was abrogated by the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin and was mimicked by the caspase-9 peptidic inhibitor LEHD-fmk. These results suggest that alpha-adrenergic activation protects cardiomyocytes against hypoxia and serum deprivation-induced apoptosis through regulating the expression of mitochondrion-associated apoptosis regulatory genes, preventing activation of mitochondrial damage-induced apoptosis pathway (cytochrome C-caspase-9), and activating hypertrophic growth.