Hypothesis: hyperstructures regulate initiation in Escherichia coli and other bacteria

Hyperstructures or modules have been proposed to constitute a level of organisation intermediate between macromolecules and whole cells. In this model of intracellular organisation, hyperstructures compete and collaborate for existence within the membrane and cytoplasm. Those directly involved in the cell cycle include initiation, replication and division hyperstructures based on DnaA, SeqA and the 2-minute cluster, respectively. During the run-up to initiation, the mass to DNA ratio increases and, we contend, differential gene expression leads to some hyperstructures becoming more active and stable than others. This results in a drop in the diversity of hyperstructures, some of which release DnaA as they dissociate, and a DnaA-initiation hyperstructure forms. Subsequent DNA replication and cell division generate different daughter cells containing different hyperstructures. This has the advantage of increasing the phenotypic diversity of the population. In developing this model, we also invoke hyperstructures in the partitioning of origins of replication.     

90Sr, 137Cs, 238Pu, 239+240Pu,and 241Am radionuclides in macrophytes within the Krasnensky flood plain: species specificity of concentration and distribution in phytocenosis components

The analysis of the content of radionuclides 90Sr, 137Cs, 238Pu, 239 + 240Pu and 241Am in water vegetation of flood plain reservoirs has allowed studing features of radionuclide accumulation by various species of macrophytes and revealing bioindicators of radionuclide contamination. Thus species-specificity of radionuclide accumulation can essentially change the contribution of different species to a percentage ratio of the radionuclide content in phytomass of reservoirs in comparison with fund of higher aquatic plants.     

Disruptions in the blood system upon exposure to low-dose ionizing radiation depending on duration of emotional stress

In experiments on rats, disturbances in the development of blood system adaptive reactions on emotional stress were found. Under the combined effect of preliminary (before stress) exposure to 0.8 Gy of gamma-radiation and the emotional stress of various duration (2, 4 and 8 days), a compensatory capability of the blood system decreased. The degree of the disturbances directly depended on the duration of the emotional stress.     

Effect of local and systemic desipramine administration on extracellular noradrenaline in the myocardium of rats

Evaluation of a local activity of the sympathetic system on the basis of norepinephrine (NE) level in the blood of myocardial vessels depends on at least three processes: NE release by sympathetic neurons, its reuptake and spillover of NE into the blood. The relations between these processes are different in various organs. Direct investigations of changes in the myocardial NE level under the effect of reuptake blockade by desmethylimipramine (DMI) were performed after appearance of the microdialysis technology. In this work the effects of local (through microdialysis membrane) and systemic administration of DMI on the NE release in a rat myocardium, were compared. Local DMI delivery increased myocardial NE level to 153 +/- 13% of the control level (0.17 +/- 0.026 ng/ml dialysate). NE concentration increased to 582 +/- 84% of control as a result of i.m. administration of 5 mg/kg DMI. No changes of the NE level in the venous blood were registered after systemic DMI. It is suggested that a relatively weak effect of local DMI is determined by saturation of DMI receptors adjacent to the probe and/or progressive diminution of the DMI effect with an increasing of the distance from the probe. Effect of systemic DMI administration depends on uniform blockade of all myocardial DMI receptors as well as the DMI influence on higher levels of the sympathetic system.     

Increase of the heart arrhythmogenic resistance and decrease of the myocardial necrosis zone during activation of cannabinoid receptors

We have found that intravenous administration of cannabinoid receptor (CB) agonist HU-210 (0.05 mg/kg), increases cardiac resistance against arrhythmogenic effect of epinephrine, aconitine, coronary artery occlusion and reperfusion in rats. Pretreatment with CB2-receptor antagonist, SR144528 (1 mg/kg), completely abolished the antiarrhythmic effect of HU-210. However this effect of HU-210 was not attenuated by pretreatment with CB1-receptor antagonist, SR141716A (3 mg/kg). We also found that HU-210 (0.05 mg/kg) decreased the relationship between infarction size and area of ischemia. It is concluded that CB2 receptor stimulation promotes an increase in the cardiac resistance against arrhythmogenic influences and probably increases myocardial tolerance of both ischemic and reperfusion damages in rats.     

Evaluation of cell membrane permeability for Ca2+ and adenylate cyclase in sheep peripheral blood cells,exposed to low doses of radiation

Chronic irradiation of sheep with doses of 2.6 and 12.9 mC.kg was characterized by the modification of the adenylatecyclase activity and Ca2+ permeability of plasma membrane in cells of the peripheric blood, with no changes in the clinical and hematological indicators. The observed effects are assumed to result from structural and dynamic variations in the lipids of membranes.     

Correlation between cataleptic freezing and prestimulation inhibition of the startle reflex in rats

In rats of GC strain bred for predisdposition to cataleptic freezing, a significant negative correlation between the duration of freezing and the level of prepulse inhibition (PPI) of the startle reflex, has been found. Besides, in a group of GC rats specific by their "nervousness" and jumpiness, there was also a negative correlation between the duration of freezing and the habituation to the startle reflex. None of this correlation have been found in Wistar rats. Since impairment of the PPI and habituation of the startle reflex is considered to be characteristic of schizophrenia, it is believed than cataleptic freezing in the GC rats may be used as a model of schizophrenic psychopathology.     

The effect of He-Ne laser radiation on myocardium mechanical activity in rats

In isolated papillary muscles, a 5-minute irradiation with the He-Ne-laser Shuttle-1 enhances the maximal strength of isometric contraction and acceleration of relaxation. In physiological mode of mechanical loads, the irradiation with the laser red light enhances the myocardium contractability at all final systolic lengths with simultaneous enhancement of the isometric relaxation velocity at great systolic lengths and a deceleration of the relaxation at lesser lengths. Under the He-Ne-laser effect, restoration of rhythm-inotropic relationships occurred in the myocardium.     

Pancreatic enzyme activity in early phases of acute experimental pancreatitis in rats

Experiments were performed on laboratory rats with acute pancreatitis caused by local freezing the pancreas with chlorethyl. An active action of enzymes alpha-amilase, lipase, phospholipase A2, was revealed. During the first hours, an increase in action of all three enzymes, particularly that of phospholipase A2, was found. It was established that the lipid spectrum of pancreas had changed. It shows that cell membranes were destroyed. Experiments revealed an activating role of Ca2+ ions for all the enzymes and a correcting action of chlorpromasine.