Antitumor activity of L-asparaginase from Yersinia pseudotuberculosis

The cytotoxic activity of L-asparaginases from Yersinia pseudotuberculosis and from Erwinia carotovora were investigated in vitro using human T-lymphoblastic leukemia (Jurkat and Molt-4) and also solid tumor cell lines MCF-7 (human breast adenocarcinoma), LnCap (human prostate carcinoma), NGUK1 (rat Gasser node neurinoma). E.coli L-asparaginase produced by Medak (Germany) was used as a reference preparation. The data obtained indicate that Y. pseudotuberculosis L-asparaginase significantly inhibits growth of leukemic and solid tumor cells. Its antitumor activity is comparable to that of the reference preparation of L-asparaginase (Medak). These results suggest that the recombinant L-asparaginase can be used for the development of new preparations for the therapy of different types of tumors.     

Ester derivatives of annulated tetrahydroazocines: a new class of selective acetylcholinesterase inhibitors

A series of ester derivatives of annulated tetrahydroazocines, namely 2,3,6,11-tetrahydro-1H-azocino[4,5-b]indoles (5-10), 2,3,6,7-tetrahydro-1H-azocino[5,4-b]indoles (11-14), and 4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocines (15-18), synthesized through an efficient 6-->8 membered ring expansion procedure, were investigated for their acetylcholinesterase (AChE) inhibitory activities. Most of the compounds acted as AChE inhibitors in vitro, with IC(50) values ranging from 5 to 40 microM. The most potent compounds 11 and 15, both as racemic mixtures, proved selective toward AChE, exhibiting selectivity ratios versus butyrylcholinesterase (BuChE) of ca. 15 and more than 20, respectively. Structure-activity studies highlighted, among other factors, lipophilicity as a property modulating the AChE inhibition potency, as shown by a reasonable parabolic correlation between pIC(50) and experimental 1-octanol/water partition coefficient (logP), which described the prevailing behavior of the examined compounds (r(2)=0.665). Molecular docking simulations using the X-ray crystal structure of AChE from Torpedo californica suggested possible binding modes of the tetrahydroazocine ester derivatives 11 and 15.     

5,10,15,20-Tetra-(N-methyl-3-pyridyl)porphyrin destabilizes the anti-parallel telomeric quadruplex d(TTAGGG)4

We studied the parameters of binding of 5,10,15,20-tetra-(N-methyl-3-pyridyl)porphyrin (TMPyP3) to the anti-parallel human telomeric G-quadruplex d(TTAGGG)4, the oligonucleotide dTTAGGGTTAGAG(TTAGGG)2 that does not form a quadruplex structure, as well as to the double stranded d(AC)8 x d(GT) and single stranded d(AC)8 and d(GT)8 DNAs. The analysis of absorption revealed that the binding constants and the number of DNA binding sites for TMPyP3 were d(AC)8 < d(GT)8 < d(AC)8 x d(GT)8 = d(TTAGGG)4 < dTTAGGGTTAGAG(TTAGGG)2. We demonstrated for the first time that the binding constant of TMPyP3 with the non-quadruplex chain dTTAGGGTTAGAG(TTAGGG)2 (1.3 x 10(7) M(-1)) is approximately 3 times bigger than the binding constant with the quadruplex d(TTAGGG)4 (4.6 x 10(6) M(-1)). Binding of two TMPyP3 molecules to d(TTAGGG)4 led to a decrease of thermostability of the G-quadruplex (deltaT(m) = -8 degrees C). Circular dichroism spectra of TMPyP3:d(TTAGGG)4 complexes revealed a shift of DNA structure from the G-quadruplex to an irregular chain. We hypothesize that partial destabilization of the telomeric G-quadruplex by TMPyP3 might be a reason for relatively low potency of this ligand as a telomerase inhibitor, as well as its marginal cytotoxicity for cultured tumor cells.     

Effector action of ethanol on the accumulation of Ca2+ in intracellular structures of uterine smooth muscle

The work is devoted to the investigation of ethanol direct effect on the transmembrane Ca2+ metabolism in the intracellular structures of myometrium. In the experiments in vitro it has been shown that the Mg2+, ATP-dependent system for Ca2+ accumulation in endoplasmic reticulum is more sensitive then Ca(2+)-accumulating system in mitochondria. It has also been found that the oxytocin insensitive part of Mg2+, ATP-dependent Ca2+ accumulation of the endoplasmic reticulum is less resistant to ethanol inhibition than the oxytocin sensitive one. The data above revealed allow to discuss mechanism of ethanol action on the intracellular Ca2+ homeostasis in myometrium.     

Evaluation on monkeys of reactogenicity and effectiveness of the complex immunoglobulin preparation formulation

Experiments on 75 monkeys, 20--healthy and 75--with diarrhea, showed that ready medicinal forms of the complex immunoglobulin preparation in tablets, capsules or in a dried form (vials) were safe, well tolerated, clinically and bacteriologically effective. When used simultaneously with antiparasitic treatment, this preparation, irrespective of the kind of its ready medicinal form, showed high curative effect (80-90%). The diarrhea ceasing was accompanied by the gradual normalization of intestinal microbiocenosis (an increased concentrations of Escherichia coli and Bifidobacterium, a decreased amount of opportunistic bacteria). The complex method of the treatment of diarrhea in monkeys (antibiotics, trichopol, phage and probiotics) made it possible to achieve curative effect only in 60% of cases, which required the additional course of treatment, namely the use of rehydration therapy.     

Protein interaction with hydrated C60 fullerene in aqueous solutions

Physicochemical effects of hydrated C(60) fullerenes (HyFn) on serum albumin molecules were studied using ESR spin labeling and differential scanning microcalorimetry. Molecular-colloidal solution of hydrated C(60) fullerenes and their small spherical fractal clusters in water (C(60)FWS), was shown to stabilize protein hydration, and decrease specific surface energy in water-protein matrix in salt solutions. The mechanism of HyFn interaction with protein is discussed in terms of HyFn induced formation of protein clusters and phase transition of hydration water.     

Fluorescent 2-pyrimidinone nucleoside in parallel-stranded DNA

Stretches of parallel-stranded (ps) double-helical DNA can arise within antiparallel-stranded (aps) Watson-Crick DNA in looped structures or in the presence of sequence mismatches. Here we studied an effect of a pyrimidinone-G (PG) base pair on the stability and conformation of the ps DNA to explore whether P is useful as a structural probe.     

Evaluation of the system for controlling the quality of the HBsAg detection in the system of screening laboratories

The two-stage control system, ensuring the high quality of serological investigations in the network of screening laboratories in Moscow was developed and introduced into practice. At the first stage the entry control of the quality of the test system for the detection of HbsAg, coming to the screening laboratories, is made in the reference laboratory with the use of specially developed "representative" panels, as well as the test systems for comparison ("reference" test systems). Then "minipanels" are formed from specimens included into the "representative" panels, which are used for the evaluation of the quality of laboratory investigations made in the screening laboratories. The high quality of such system for controlling the quality of the detection of HBsAg in the screening laboratories of Moscow is shown.     

Can Stress-Induced CAM Provide for Performing the Developmental Program in Mesembryanthemum crystallinum Plants under Long-Term Salinity?

The development of CAM-type photosynthesis is one of the adaptation mechanisms to severe water deficit. It provides plants with carbon dioxide and permits efficient water spending under extreme environments. In common ice plants, a complete switch from C₃ to CAM photosynthesis was observed on the seventh day of salinity (0.5 M NaCl). The indices characterizing this switch were: (1) induction of phosphoenolpyruvate carboxylase; (2) diurnal changes in the organic acid content, which are characteristic of CAM plants, and (3) suppression of transpiration during the daytime. A decrease in the osmotic potential () of the leaf sap, which occurred on the second day of salinity, preceded these changes. After long-term salinity stress (four–five weeks), attained extremely low values (–4.67 MPa), which made possible the water uptake by the root system. The restoration of the balance between cell compartments resulted from the accumulation of compatible solutes in the cytoplasm, proline primarily, which possesses osmoregulatory and stress-protective properties. This means that a complex of adaptive mechanisms is required for the realization of the common ice developmental program under salinity. These mechanisms maintained plant capacity to uptake water and permitted its efficient utilization. They triggered the development of stress-induced CAM-type photosynthesis, maintained the low osmotic potential in the cell sap, regulated the composition of macromolecules in the cell microenvironment, provided for water storage in tissues, and reduced the time of plant development. A comparison between the time-courses of CAM development and a decrease in the transpiration rate permitted us to suggest that a combination of low and CO₂ in the leaf cells could serve as a signal for the induction of CAM-dependent gene expression in terrestrial plants.