The separation of subunits of phenylalanyl-tRNA-synthetase from Escherichia coli MRE-600 by means of affinity chromatography in dissociation conditions

The method of affinity chromatography on sepharose with immobilized tRNA in the presence of urea was developed for separating the subunits of phenylalanyl-tRNA synthetase from E. coli MRE-600 (subunit structure alpha 2 beta 2). Specific binding of large beta-subunits of the enzyme on immobilized tRNA testifies the localization of the tRNA-binding center on the beta-subunit of phenylalanyl-tRNA synthetase. Separately alpha- and beta-subunits of the enzyme exhibit no catalytic activity. Incubation of the mixture of alpha- and beta-subunits in conditions leading to reassociation of the oligomeric structure results in restoration of catalytic activity of the enzyme. In the presence of urea resin with immobilised analogs of ATP binds alpha- and beta-subunits of the enzyme. This testifies the presence of nucleotide-binding sites on both subunits. The possibility of using the affinity chromatography method to separate non-identical subunits of different enzymes is discussed.     

Effect of medicinal plants on the antilysozyme activity of microorganisms]

Medicinal plants effect on antilysozyme activity of E. coli, Klebsiella, S. aureus, Candida, Bifidobacterium, Bacteroides, Clostridium was evaluated in vitro. It was demonstrated that the effects differed substancially according to the microorganism taxonomy. The experimental data on the plants inhibitory activity may be used for elaboration of effective regimes of infections and disbiosis treatment.     

Nature of the ligand bound to uncoupling CSP310 protein

It was shown that, in preparations of winter rye (Secale cereale L.) and winter wheat (Triticum aestivum L.), in proteins immunochemically related to a cold shock protein CSP310, and also in purified CSP310 from winter rye and triticale (Triticosecale X.), nucleic acid was present. Treatments with DNase and RNase showed that this nucleic acid was RNA. This protein-bound RNA was detected in the preparation of constitutively synthesized but not stress-induced protein. Stress-induced CSP310 bound high-molecular RNA in vitro at both 26 and 0°C, but it did not bind DNA. The data obtained permit an assumption that, during low-temperature stress, constitutively synthesized CSP310 with a low uncoupling capacity releases RNA and transits to a stress-induced form with a high uncoupling capacity.Translated from Fiziologiya Rastenii, Vol. 52, No. 2, 2005, pp. 216–220.Original Russian Text Copyright © 2005 by Kolesnichenko, Tauson, Zykova, Klimenko, Grabelnykh, Pobezhimova.This revised version was published online in April 2005 with a corrected cover date.     

Mechanisms and functions of nonphosphorylating electron transport in respiratory chain of plant mitochondria

Data are raeviewed on mitochondrial systems whose functioning in plants diminishes the efficiency of oxidative phosphorylation. The involvement in this process of alternative oxidase, thermogenin-like uncoupling proteins, a 310 kD stress protein, free fatty acids, and the ADP/ATP antiporter is considered. The role of these systems is discussed with regard to thermogenesis, controlled production of reactive oxygen species, and regulation of bioenergetics and metabolism.     

The search for proteins with immunochemical affinity to plant stress proteins at cold-adapted endemic Baikal fishes

The search for proteins with immunochemical affinity to plant stress proteins in endemic Baikal fishes shows the presence of proteins, immunochemically related to plant heat-stabile proteins and plant uncoupling protein CSP 310. Western blotting showed that among the native cytoplasmic proteins of endemic Baikal fishes there are proteins immunochemically related to heat-stabile plant proteins with molecular weights about 480, 200-290, 150, 140 and about 90-100kD. SDS-electrophoresis showed the presence of polypeptides with molecular weights 23, 17 and 14kD in all species investigated and an additional 35kD polypeptide in Cottocomephorus grewingki. The search for polypeptides with immunochemical affinity to plant stress uncoupling protein CSP 310 in endemic Baikal fishes shows the presence of a 14kD polypeptide, immunochemically related to it.     

The Relationship between Fenestrations,Sieve Plates and Rafts in Liver Sinusoidal Endothelial Cells

Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane. The effects of cytochalasin D on fenestrations were abrogated by co-administration of Triton X-100, suggesting that actin disruption increases fenestrations by its effects on membrane rafts. Vascular endothelial growth factor (VEGF) depleted lipid-ordered membrane and increased fenestrations. The results are consistent with a sieve-raft interaction, where fenestrations form in non-raft lipid-disordered regions of endothelial cells once the membrane-stabilizing effects of actin cytoskeleton and membrane rafts are diminished.     

Carbon and Nitrogen Mineralization of Lead Treated Soils in the Eastern Mediterranean Region,Turkey

The aim of this study was to determine the first effect of lead on microbial activity in soil. The study was carried out in the soil samples from four different radish (Raphanus sativus L. var. radicula, Brassicaceae) fields along the highway in a district (Kadirli, Osmaniye) of the Eastern Mediterranean Region, Turkey. After the calculation of Pb contents, the Pb amounts of the soil samples were brought up to 50 and 100 mg Pb kg^?1 by treatment with Pb(NO ₃ ) ₂ , and the samples for the carbon and the nitrogen mineralization were incubated under controlled conditions (28°C, constant moist). The carbon mineralization was determined by a CO ₂ respiration method for 30 days. The nitrogen mineralization was observed in vitro for 6 weeks. The untreated group was statistically different from the 50 and 100 mg Pb kg^?1 treatments in the aspect of the C(CO ₂ ) outlet during mineralization (P ≤ 0.05), but difference between the 50 and 100 mg Pb kg^?1 treatments was not significant. NH ₄ -N and NO ₃ -N contents of each soil were shown differences between across treatments. Based on these results, it is possible to conclude that the addition of 50 and 100 mg Pb kg^?1 provided a toxic effect threshold for the microbial activity into 30 days.