Search results for "Rite"

Molecular response to TBT stress in marine sponge Suberites domuncula: proteolytical cleavage and phosphorylation of KRS_SD protein kinase

2003

Abstract Marine sponges as sessile filter feeders are inevitably under a constant influence of changes in their environment. Mediation of extracellular signals and regulation of cellular response to environmental stress is a key function of cellular protein kinases. Expression, proteolytical cleavage and phosphorylation of stress-responsive KRS_SD protein kinase, in control and tributyl-tin (TBT) treated sponges were investigated. In control sponge, two KRS_SD proteins were expressed: KRS_SD1 (54 kDa) corresponding to KRS_SD calculated molecular weight, and KRS_SD2 (50 kDa). Exposure of sponges to TBT resulted in alteration of KRS_SD1 and KRS_SD2 expression levels and their phosphorylation …

Triterpene saponins from Schefflera abyssinica

2006

Biologically and Pharmacologically Active Saponins from Plants: Recent Advances

2000

Saponins as triterpene or steroid glycosides were well known in ancient times for their detergent, haemolytic and fish toxic activities, properties which are correlated with the amphiphilic character of the molecules and their ability to complex cholesterol.

Expression of silicatein and collagen genes in the marine sponge Suberites domuncula is controlled by silicate and myotrophin

2000

The major skeletal elements in the (Porifera) sponges, are spicules formed from inorganic material. The spicules in the Demospongiae class are composed of hydrated, amorphous silica. Recently an enzyme, silicatein, which polymerizes alkoxide substrates to silica was described from the sponge Tethya aurantia. In the present study the cDNA encoding silicatein was isolated from the sponge Suberites domuncula. The deduced polypeptide comprises 331 amino acids and has a calculated size of Mr 36 306. This cDNA was used as a probe to study the potential role of silicate on the expression of the silicatein gene. For these studies, primmorphs, a special form of aggregates composed of proliferating c…

Electrochemical reduction of the nitrite to ammonium ions in presence of [MoO2(O2CC(S)C6H5)2]2−

1995

Abstract Ammonia is formed during potentiostatic reduction of sodium nitrite solutions on the nafion-complex-coated electrode. When (NH4)2[MoO2(O2CC(S)(C6H5)2)2] is present in NaNO2 solutions a polarographic wave is associated to electrocatalytic reduction of nitrite ion. The wave height varies linearly on the concentration of nitrite ion, allowing a procedure for analysing this ion. This electrochemical behaviour distinguishes the nitrite from the nitrate ions. The Mo(VI), Mo(V), and Mo(IV) are involved in catalytic redox processes determining formation of NH4+ from nitrite ions.

INTERACTION BETWEEN SODIUM NITRITE AND BETA ADRENERGIC BLOCKERS ON ISOLATED RAT AORTA

1978

Electrosynthesis of Stable Betulin‐Derived Nitrile Oxides and their Application in Synthesis of Cytostatic Lupane‐Type Triterpenoid‐Isoxazole Conjuga…

2021

Cyclic Sulfonimidates by Dynamic Diastereomer-Differentiating Cyclisation: Large-Scale Synthesis and Mechanistic Studies

2001

A dynamic diastereomer differentiating cyclisation is the key step in a new large-scale synthesis of both enantiomers of the cyclic sulfonimidates 1 (Aldrich no. 54099-4) and ent-1 (Aldrich no. 54412-4). These are valuable starting materials in the asymmetric synthesis of chiral oxa- and azaheterocyclic compounds. NMR spectroscopic studies on the reacting system reveal N-chloro sulfinamides to be reactive intermediates in the oxidative chlorination of sulfinamides with tert-butyl hypochlorite and allow for the inspection of the configurational behaviour of the involved sulfonimidoyl chlorides and sulfonimidoyl bromides.

NMR and Infrared Spectroscopies of C-S-H and Al-Substituted C-S-H Synthesised in Alkaline Solutions

1998

(C,N)-(S,A)-H samples have been synthesised from mixes of different CaO/SiO2 and AI(OH)3/SiO2 ratios in stirred suspensions in more or less concentrated soda solutions. The stoichiometry and spectroscopic characteristics of samples have been studied by FTIR, 27A1 and 29Si MAS NMR spectroscopies. The structural changes induced by substitutions have been discussed on the basis of the dreiketten structure of the tobermorite silicate chains.

ChemInform Abstract: ortho Effect on the Nitrosation of the 2,3-Diphenyl-5-(2-methoxyphenyl)pyrrole.

1990

A comparison of the behaviour on the nitrosation of the isomers 5-(2-methoxyphenyl)- (1a) 5-(3-methoxyphenyl)- (1b) and 5-(4-methoxyphenyl)2,3-diphenylpyrroles (1c) carried out in the usual way with iso-amyl nitrite in a solution of sodium ethoxide in ethanol evidences that 1a is dramatically less reactive with respect to 1b and 1c. The different reactivity was ascribed to the occurrence of a strong hydrogen bond involving pyrrole NH and the ortho-methoxy group.