Role of Auxin in Induction of Polarity in Fucus vesiculosus Zygotes

We studied the effects of auxin (indole-3-acetic acid) on formation of the primary polarity axis in zygotes of the brown algae Fucus vesiculosusL. Within the first 2.5 h after fertilization, the zygotes release this phytohormone in the ambient medium. The treatment of developing zygotes with the inhibitor of indole-3-acetic acid transport from the cell 2,3,5-triiodobenzoic acid at 5 mg/l arrests the auxin secretion and leads to its accumulation in the cells. This causes a significant delay in zygote polarization. The treatment of zygotes with the exogenous indole-3-acetic acid at 1 mg/l stimulates cell polarization and formation of a rhizoid protuberance. When auxin was added to the medium with triiodobenzoic acid, the inhibitory effect of the latter was eliminated. It has been proposed that the content of indole-3-acetic acid in the ambient medium is a key factor in the induction of polarity of the F. vesiculosus zygotes.     

Systemic delivery of complexes of melanoma RNA with mannosylated liposomes activates highly efficient murine melanoma-specific cytotoxic T cells in vivo

The efficiency of the antitumor immune response triggered by dendritic cell (DC)-based vaccines depends predominantly on the efficiency of delivering tumor antigen-coding nucleic acids into DCs. Mannosylated liposomes were used to deliver tumor total RNA into DCs both ex vivo and in vivo, and the cytotoxic T-lymphocyte (CTL) antitumor response was assayed. The liposomes contained the mannosylated lipid conjugate 3-[6-(α-D-mannopyranosyloxy)hexyl]amino-4-{6-[rac-2,3-di(tetradecyloxy)prop-1-yl oxycarbonylamino]hexyl}aminocyclobut-3-en-1,2-dione), the polycationic lipid 2X3 (1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosane tetrahydrochloride), and the zwitterionic lipid DOPE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) at a molar ratio of 1: 3: 6 and were used as a transfection agent. Total RNA isolated from B16-F10 mouse melanoma cells served as a source of tumor antigens. Systemic administration of mannosylated liposomes–tumor RNA complexes into circulation of melanoma- bearing mice induced an efficient CTL response, which reduced the melanoma cell index in vitro with the same efficiency (by a factor of 2.8) as CTLs activated via an inoculation of DCs loaded with complexes of the same composition ex vivo. Complexes of tumor RNA with control liposomes, which lacked the mannosylated lipid conjugate, or DCs transfected with these complexes ex vivo were less efficient and reduced the melanoma cell count by a factor of only 1.6–1.8.     

Computational architecture of the yeast regulatory network

The topology of regulatory networks contains clues to their overall design principles and evolutionary history. We find that while in- and out-degrees of a given protein in the regulatory network are not correlated with each other, there exists a strong negative correlation between the out-degree of a regulatory protein and in-degrees of its targets. Such correlation positions large regulatory modules on the periphery of the network and makes them rather well separated from each other. We also address the question of relative importance of different classes of proteins quantified by the lethality of null-mutants lacking one of them as well as by the level of their evolutionary conservation. It was found that in the yeast regulatory network highly connected proteins are in fact less important than their low-connected counterparts.     

Influence of UV-light and dexamethasone on functional properties of lymphocytes and neutrophils

UV-light and dexamethasone influence on functional properties of lymphocytes and neutrophils of peripherical donors' blood was studied. An increase of phagocytic activity of neutrophils was observed after their incubation with photomodified lymphocytes. It was found that UV-irradiation of lymphocytes activated synthesis of interleukines 1beta and 2. Dexamethasone presence in lymphocyte suspension inhibited the synthesis of the studied cytokines, especially by the incubation with photomodified cells. It was shown by the method of fluorescent labels that UV-irradiation improved interaction between dexamethasone and cell membrane.     

Role of Opiate Receptors and ATP-Dependent Potassium Channels of Mitochondria in the Formation of Myocardial Adaptive Resistance to the Arrhythmogenic Effect of Ischemia and Reperfusion

Preliminary stimulation of opiate receptors (ORs) by intravenous administration of agonist DALDA (0.5 mg/kg), ₁ agonist DPDPE (0.5 mg/kg), and agonist (-)-U-50.488 (1 mg/kg) increases rat myocardial resistance to arrhythmogenic effect of coronary occlusion (10 min) and reperfusion (10 min). Activation of ₂ ORs (DSLET, 0.5 mg/kg) has no effect on the incidence rate of ischemic and reperfusion arrhythmias. Preliminary administration of glibenclamide (0.3 mg/kg), an inhibitor of K_ATP channels, blocks the antiarrhythmic effect of DALDA and DPDPE. Repeated short-term exposures of rats to immobilization within two weeks increases the heart tolerance to the arrhythmogenic effect of coronary occlusion and reperfusion. This effect disappears after administration of CTAP (0.5 mg/kg), a antagonist, or injection of 5-hydroxydecanoate (5 mg/kg), an inhibitor of mitochondrial K_ATP channels. The selective antagonists of and ORs have no effect on cardiac adaptation-induced resistance to the arrhythmogenic effect of ischemia and reperfusion. We believe that stimulation of , , and ORs increases myocardial tolerance to the arrhythmogenic effect of ischemia and reperfusion through activation of K_ATP channels. The antiarrhythmic effect of the adaptation is mediated by stimulation of ORs and mitochondrial K_ATP channels.     

Role of auxin in induction of polarity in zygotes of Fucus vesiculosus L

We studied the effects of auxin (indolyl-3 acetic acid) on formation of the primary polarity axis in zygotes of the brown algae Fucus vesiculosus. Within the first 2.5 h after fertilization, the zygotes release this phytohormone in the environment. The treatment of developing zygotes with the inhibitor of indolyl-3-acetic acid transport from the cell triiodobenzoic acid at 5 mg/l arrests the auxin secretion and leads to its accumulation in the cells. This causes a significant delay in zygote polarization. The treatment of zygotes with the exogenous indolyl-3-acetic acid at 1 mg/l stimulates cell polarization and formation of a rhizoid process. When auxin was added to the medium with triiodobenzoic acid, the inhibitory effect of the latter was fully relieved. It has been proposed that the content of indolyl-3-acetic acid in the environment is a key factor in the induction of polarity of the F. vesiculosus zygotes.     

Alterations of inotropic function of isolated heart and extent of injury of cardiomyocytes after cannabinoid receptor activation during ischemia and reperfusion

It was found that CB1- and CB2-receptor activation by intravenous administration of the selective CB-agonist HU-210 at a dose 0.1 mg/kg prompts an increase of myocardial resistance to the pathogenic action of ischemia and reperfusion in vitro. The revealed effects of HU-210 do not depend on the activation of CB-receptors in the myocardium.     

Changes in cardiac resistance to arrhythmogenic effects during ATP-dependent K+ channel activation

It has been found that pretreatment with ATP-dependent potassium channel (KATP-channel) opener, BMS 180448 (3 mg/kg, intravenously), increases cardiac resistance against arrhythmogenic action of coronary artery occlusion and reperfusion in anaesthetized rats. However, BMS 180448 induced a decrease in ventricular fibrillation threshold in rats postinfarction cardiac fibrosis. This effect was completely abolished by administration of the KATP-channel inhibitor, glibenclamide. By contrast, coadministration of BMS 180448 and selective sarcolemmal KATP-channel inhibitor, HMR 1098, promoted an increase in ventricular fibrillation threshold in rats with postinfarction cardiac fibrosis before normal value. The selective mitochondrial KATP-channel opener, diazoxide, also exacerbated a decrease in ventricular fibrillation threshold induced by postinfarction cardiac sclerosis. But after depletion of endogenous catecholamine storage by pretreatment with guanthidine, diazoxide, on the contrary, elevated the ventricular fibrillation threshold. It has been suggested that stimulation of mitochondrial ATP-sensitive potassium channels promotes an elevation in electrical stability of the heart, whereas opening of sarcolemmal KATP-channel increases a possibility of ventricular arrhythmias.     

Synthesis of cationic amphiphiles on the basis of deoxycholic acid

Cationic derivatives of deoxycholic acid with N,N-dimethylenediamine, epsilon-aminocaproic acid, and pyridine as polar heads were synthesized. The cationic groups were linked to 3alpha- and 12alpha-hydroxy groups of the steroid moiety through ester or urethane bonds. Liposomal formulations of the compounds synthesized may be used for gene delivery in cells. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 5; see also http: //www.maik.ru.     

Regeneration of myocardium

It has been systematized modern data on the myocardial regeneration and the regulation of cardiac cell proliferation in mammals and man. It has been performed an analysis published works which indicate that cardiomyocyte division and DNA synthesis in myocardial cells increase in many times during different pathological conditions. It has been generalized and analyzed results of experimental and clinical researches on the participation of stem cells in the regeneration of the heart. It has been present literature data on the telomeres and telomerase in cardiomyocytes.