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.

Emulsifiable composition for the control of insects

Abstract: An emulsifiable composition for the control of insects, especially of termites, comprising as active ingredients a 1-substituted phenyl 3-CN pyrazole and a weakly polar solvent and an emulsifying agent, and optionally some further additives or solvents. These compositions avoid the formation of crystals.

Dentifrice-compatible silica particulates

Abstract: Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry, as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm 2 , of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH≦7.5-0.7 log(C) and pH≧5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH≦8.5-0.4 log(D) and pH≧7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO 2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens·cm -1 . In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH - functions thereof, expressed in OH - /nm 2 , is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens·cm -1 .

Cytochrome P-450 2E1 is not the sole catalyst of chlorzoxazone hydroxylation in rat liver microsomes. off.

Abstract: The contribution of individual cytochrome P-450 isozymes in the hydroxylation of the centrally acting skeletal muscle relaxant chlorzoxazone was determined in rat liver microsomes. The hydroxylation rate of chlorzoxazone was found to be 50% greater in male than female microsomes. Kinetic studies using control male microsomes showed that chlorzoxazone hydroxylation was biphasic with a calculated low Km (33 microM) and high Km (116 microM). Liver microsomes from isoniazid-, beta-naphthoflavone- or dexamethasone-treated male rats produced a Km of 93, 69 and 26 microM, respectively. When chlorzoxazone hydroxylation activity was measured at a high substrate concentration (200 microM), treatment of male rats with isoniazid, acetone, beta-naphthoflavone and dexamethasone produced increases in the activity rate of 124%, 117%, 81% and 32%, respectively. However, when the activity was measured at a low substrate concentration (2 microM), liver microsomes from dexamethasone-treated male and female rats produced 5- and 10-fold induction, respectively. In immunoinhibition studies at 200 microM of chlorzoxazone, antibodies specific for cytochrome P-450 2E1 inhibited the rate of chlorzoxazone hydroxylation in microsomes from control and isoniazid-treated male rats by 68% and 79%, respectively. A monoclonal antibody (C8) against P-450 1A1 inhibited 67% of the activity in microsomes from beta-naphthoflavone-treated male rats but was ineffective inhibiting chlorzoxazone hydroxylation in microsomes from control or dexamethasone-treated male rats. In liver from control female rats, antibodies against cytochrome P-450 2E1 inhibited 80% of chlorzoxazone hydroxylation, whereas it inhibited only 47% of the activity in dexamethasone-treated females.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary structure, expression in Escherichia coli, and properties of S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase from Bacillus megaterium.

Abstract: A Bacillus megaterium DNA fragment encoding S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase (SUMT) activity was subcloned and sequenced. The encoded polypeptide showed more than 43.5% strict homology to Pseudomonas denitrificans SUMT (F. Blanche, L. Debussche, D. Thibaut, J. Crouzet, and B. Cameron, J. Bacteriol. 171:4222-4231, 1989). The B. megaterium polypeptide was overexpressed in Escherichia coli, partially purified, and shown to exhibit, like P. denitrificans SUMT, substrate inhibition at uroporphyrinogen III concentrations above 0.5 microM, suggesting a common regulation for aerobic cobalamin-producing organisms.