Advanced Variants of HTSC Wires for ТRТ Electromagnetic System

Plasma Physics Reports - The possibility of fabricating winding wires for electromagnetic systems of a tokamak-type reactor using high-temperature superconductors (HTSC) operating at temperatures...     

Antiesterase activity and toxicity of O,O-dialkyl-S-ethoxycarbonylbromomethylthiophosphates

The interaction of potential pesticides, O,O-dialkyl S-ethoxycarbonylbromomethylthiophosphates (RO)2P(O)SCH(Br)COOC2H5 (R = Et, i-Pr, n-Pr, n-Bu, n-Am, or n-Hx) with the esterases of warm-blooded animals [acetylcholinesterase (ACE), butyryl cholinesterase (BCE), and carboxyl esterase (CE)] was studied. The acute toxicities of these compounds for mice were determined. All the compounds were non-hydrolyzable by CE and capable of irreversible inhibition of all these esterases with ki (M-1 min-1) of 1.2 x 10(5)-6 x 10(6), 2.0 x 10(6)-1.5 x 10(8), and 2.0 x 10(8), respectively. By using multiple regression analysis, we found that the steric factor plays a significant role in the inhibition of ACE, with the steric hindrances manifesting themselves even at the sorption stage. On the other hand, hydrophobic interactions predominate in the case of BCE, while steric properties of its substituents exert a markedly weaker effect and manifest themselves at the phosphorylation stage. We suggested the presence of an electrophilic region in the active site of ACE, which can interact with the ethoxycarbonyl group of the thiophosphates under study. The decrease in toxicities and the affinities to BCE and CE were found to correlate with an increase in the length of n-alkyl substituents of the compounds studied. This suggests that the unspecific esterases play a significant role as a buffer system in the exhibition of toxic effects by the thiophosphates under consideration.     

Factors controlling the biosynthesis of chlorosome antenna bacteriochlorophylls in green filamentous anoxygenic phototrophic bacteria of the family Oscillochloridaceae

We determined the concentrations of bacteriochlorophylls (BChl) in the light-harvesting antennae of Oscillochloris trichoides (of the family Oscillochloridaceae belonging to green filamentous mesophilic bacteria) cultivated either with gabaculine, an inhibitor of the C-5 pathway of BChl biosynthesis in a number of bacteria, or at various illumination intensities. We determined the BChl c: BChl a molar ratios in intact cells, in chlorosome-membrane complexes, and in isolated chlorosomes. We revealed that BChl c synthesis in Osc. trichoides was more gabaculine-sensitive than BChl a synthesis. Accordingly, an increase in gabaculine concentrations in the medium resulted in a decrease in the BChl c: BChl a ratio in the tested samples. We suggest that BChl synthesis in Osc. trichoides proceeds via the C-5 pathway, similar to representatives of other families of green bacteria (Chlorobium limicola and Chloroflexus aurantiacus). We demonstrated that the BChl c: BChl a ratio in the chlorosomes varied from 55 : 1 to 110 : 1, depending on light intensity. This ratio is, therefore, closer to that of Chlorobiaceae, and it significantly exceeds the BChl c: BChl a ratio in Chloroflexaceae.     

The effect of synthetic proteinase inhibitors of the level of human recombinant proinsulin production, secreted by a genetically engineered strain of Bacillus subtilis

Influence of O,O,-diethyl-1-(N-alpha-hydrohexafluoroisobutyryl)amino-1- methylpropylphosphonate and O,O-diisobutyl-1-[2-(ethoxycarbonyl)aminoperfluoroprop-2-yl] -1- methylpropylphosphonate on the level of production of human proinsulin secreted by a genetically engineered culture Bacillus subtilis AJ 73 (pBINS1.0.) has been studied. The above phosphonates, being non-toxic for microorganisms, reduced degradation of proinsulin by serine proteinases.     

Synthesis,Fungistatic, Protistocidal,and Antibacterial Activity of 1-(3-Amino-2-Hydroxypropyl)Indoles

A series of new indole derivatives containing the 3-amino-2-hydroxypropyl group at the nitrogen atom has been synthesized by the ring-opening of the oxirane cycle of 1-oxiranylmethylindoles. Their antibacterial, fungicidal, and protistocidal activities have been studied. Most of the synthesized compounds have been shown to exhibit a high protistocidal activity that several times exceeds that of the reference drug, baikoks (toltrazuril).     

Synthesis of new 1-alkyl-, 1-benzyl-, and 1-aryloxyethyl-substituted 4,5-dichloroimidazoles and their antimicrobial,protistocidal, and fungistatic properties

Previously unknown 1-alkyl-, 1-benzyl-, and 1-aryloxyethylderivatives of dichloroimidazoles and products of their structural transformation were synthesized from 4,5-dichloroimidazole or 2-methyl-4,5- dichloroimidazole using alkyl, benzyl or aryloxyethyl halides. These N-substituted compounds were shown to have a weak antibacterial activity against some pathogenic gram-positive and gram-negative bacteria (Staphylococcus aureus and Escherichia coli). At the same time, some of the obtained compounds demonstrated a significant protistocidal activity against Colpoda steinii, which can exceed in strength the activity of clinically used veterinary drug Baycox. Moreover, these compounds showed a pronounced fungistatic effect.     

Recyclization of 9-bromocotarnine under the action of haloacylhetarenes. Synthesis and biological activity of the 4-heteroaroyl-9-bromo-1,2-dihydro-6-methoxy-7,8-methylenedioxy-3-benzazepines

Reaction of 9-bromocotarnine with heterocyclic α-halo ketones is accompanied by the expansion of the six-membered dihydropyridine ring to seven-membered dihydroazepine one and leads to previously unknown 4-heteroaroyl-9-bromo-3-methyl-1,2-dihydro-6-methoxy-7,8-methylenedioxy-3-benzazepines. It has been shown that some of the resulting compounds exhibit a significant antibacterial activity against Staphylococcus aureus and Escherichia coli. At the same time, the synthesized benzazepines have shown no significant protistocidal activity against Colpoda steinii and fungistatic activity against Penicillium italicum.     

Synthesis and Anti-Infective Activity of 2-Heteroaryl(Acyl)-9,10,12,13-Tetramethoxy-3-Methyl-4,5-Dihydro-3<Emphasis Type="Italic">H</Emphasis>-Phenanthro[1,2-<Emphasis Type="Italic">d</Emphasis>]Azepines

2-Hetaryl- and 2-acyl-9,10,12,13-tetramethoxy-3-methyl-4,5-dihydro-3H-phenanthro[1,2-d]-azepines have been synthesized from 8,9,11,12-tetramethoxy-2-methyl-3,4-dihydronaphtho[2,1-f]isoquinolinium perchlorate by pyridine-azepine recyclization. The resulting compounds have revealed a pronounced antibacterial activity against Staphylococcus aureus (strain P-209) and Escherichia coli (field strain 078). Some of these compounds have a moderate fungistatic activity against Peniciliium italicum fungi. Two compounds have shown a certain activity in relation to the Colpoda steinii protozoa.     

Effects of the γ-aminobutyric acid antagonist disulfotetraazaadamantane on evoked neuronal response in hippocampal slices

The effects were investigated of disulfotetraazaadamantane (DSTA), a blocker of -aminobutyric acid, on summated potentials in field CA 1 of the mouse hippocampus arising in response to electrical stimulation of Shaffer's collateral. At a concentration of 5·10^–6–10^–5 M, DSTA led to a considerable increase in the amplitude of the main population spike (PS) and the onset of additional PS. The effects induced by DSTA resembled those observed following picrotoxin application, which it exceeded two- to threefold in intensity, however. Findings are reviewed from the standpoint of the effects exerted by the test substance on synaptic processes in the hippocampus in vitro.Institute of Physiologically Active Substances, Academy of Sciences of the USSR, Chernogolovka, Moscow Oblast. Institute of Brain Research, National Scientific Mental Health Center, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 21, No. 1, pp. 66–70, January–February, 1989.     

Nonlinear "hydrophobicity-antiesterase activity" model for various types of organophosphorous compounds

The dependence of antiesteratic activity on the structure of insecticides (RO)2P(O)SCH(COOEt)SP(O)(OR)2 (I) and (RO)2P(O)SCH(COOEt)OP(S)(OR)2 (II) was examined. Nonlinear regression equations (parabolic and bilinear) "hydrophobicity-antiesteratic activity" were derived. Basing on the studies of the relationships between hydrophobicity and individual constants, the detailed mechanisms were proposed for the interaction of type (I) and (II) compounds with the esterase active centers. The mechanisms implicate different kinds of sorbtion for compounds of type I and II. Applicability of bilinear models, similar to that of Kubinyi type, for analyzing the structure-antienzyme activity dependences was demonstrated. Thus, several equations were obtained starting from the literature data on inhibition of esterases with diverse organophosphorus compounds.