[Antirestriction activity of the mercury resistance nonconjugative transposon Tn5053 is controlled by the protease ClpXP].

When transformed into Escherichia coli K12 strains, the mercury resistance transposon Tn5053@ exhibits high antirestriction activity against the EcoKI type I restriction and modification system. The products of the genes merR and ardD contribute to the antirestriction activity of Tn5053. The merR gene encodes the MerR protein, the transcription regulator of the mer operon genes. The ardD gene is responsible for ArdD protein synthesis and is located within the tni operon. In the following study, it was demonstrated that the antirestriction activity of the transposon Tn5053 is absent in E. coli K12 strains with the mutant genes clpX, clpP, and recA. The antirestriction effect of Tn5053 is not enhanced by 2-aminopurine. The Tn5053 antirestriction activity is not altered in E. coli K12 with the mutant dam gene; however, it is decreased in the E. coli K12 mutD. It is assumed that the activities of the MerR and ArdD proteins lead to the formation of a significant amount of unmodified DNA in the bacterial cell, causing the SOS-dependent reduction of the EcoKI (R2M2S) enzyme activity associated with ClpXP-induced proteolysis of the R-subuinit.

[Trigger factor dependent refolding of bacterial luciferases in Escherichia coli cells: kinetics, efficiency and effect of the bichaperone system, DnaKJE-ClpB].

Here were determined the basic parameters of the Tigger Factor (TF) -dependent refolding of thermal inactivated bacterial luciferases. The TF-dependent refolding is less efficient and requires more time than DnaKJE-dependent refolding. The increase in the intracellular concentration of TF leads to an apparent decrease in the level of the thermal inactivated bacterial luciferase refolding. For thermolabile luciferases, the level of TF-dependent refolding is significantly higher, than for thermostable luciferases: 30-40%--for the thermolabile Aliivibrio fischeri and Photobacterium leiognathi luciferases, and 10 and 0.5% for the thermostable Vibrio harveyi and Photorhabdus luminescens luciferases, respectively. The negative effect of the ClpB protein on the TF-dependent refolding was shown: in Escherichia coli clpB::kan TF-dependent refolding is more efficient than in the E. coli clpB+.

[Effects of the IbpAB AND ClpA chaperones on DnaKJE-dependent refolding of bacterial luciferases in Escherichia coli cells].

The rate and level of DnaKJE-dependent refolding of the thermoinactivated Aliivibrio fischeri luciferase are considerably lower in Escherichia coli ibpA and ibpB mutants than in wild type cells. The rate and level of refolding are lower in E. coli ibpB::kan than in ibpA::kan cells. The decline of refoldings level in E. coli clpA::kan makes progress only with the increase of thermoinactivation time of luciferase. Plasmids with the genes ibpAB don't compensate clpA mutation. It is supposed that small chaperones IbpAB and chaperone ClpA operate independently in a process of DnaKJE-dependent refolding of proteins at the different stages.

[Proteolytic control of expression of Vibrio fischeri lux-operon genes in Escherichia coli cells].

The key elements of the regulatory system activating expression of the lux-operon genes in the sea bacteria Vibrio fischeri are the LuxR protein (an activator oftranscription) and N-(3-oxohexanoyl) L-homoserine lactone (an autoinducer, AI). It is shown that the ATP-dependent proteases ClpXP and Lon take part in the negative control of expression of the lux-operon genes and that AI protects the LuxR protein from proteolysis.

[The C-terminal domain of the Vibrio fischeri transcription activator LuxR is not essential for degradation by Lon protease].

The Vibrio fischer luxICDABEG genes are activated by autoinducer N-(3-oxohexanoyl)homoserine lactone and the LuxR protein. The LuxR contains 250 aa and consists of two domains. The C-domain, that extends from around residue 162 to the C-terminus, is thought to bind lux regulatory DNA and activate transcription of the luxICDABEG genes. The N-terminal domain, which binds the autoinducer, consists of about 70% residues of LuxR. In E. coli C-terminal domain can activate the lux genes in the absence of autoinducer. Previously it was shown that the ATP-dependent Lon protease of E. coli takes part in the negative regulation of the transcription of the V. fischeri lux operon and that LuxR is a target of Lon protease. Comparative analysis of effects of Lon protease on the V. fischeri luxICDABEG genes expression was made. Special constructed hybrid plasmids which permit the regulation of luxR, luxR 5'-deletion mutation were used and luICDABEG genes were activated independently and quantitatively. We show that the full length LuxR, but not C-terminal domain is a target protein for Lon protease. The transcription activity by full length LuxR protein isobserved when its intracellular concentration is about two order lower than that of its C-terminal domain.

[Mutation clpA::kan in gene encoding the chaperone of Hsp100-family decreases DnaK-dependent refolding efficiency of proteins in Escherichia coli cells].

The rate and level of DnaK-dependent refolding of the thermoinactivated Vibrio fischeri luciferase were considerably lower in clpA mutant (clpA::kan) then in wild type cells. The decline of level of refolding makes progress with the increase of thermoinactivation time of enzyme. The mutation in clpP gene has no influence on kinetic and level of luciferase refolding. It was shown that the approximately equal amounts of the DnaKJE chaperone are synthesized under "heat shock" induction in E. coli clpA+ and E. coli clpA::kan cells. We suppose that the chaperone ClpA (like homological chaperone ClpB) is involved in the disaggregation process of denaturized proteins and that results to the increase of refolding efficacy. This in vivo phenomenon occurs only under long time incubation of cells at a high temperature, i.e. when protein aggregates of large size poorly refoldable by the DnaKJE system are formed.

[Signs of metabolic syndrome in combinations of hypertension with coronary risk factors].

Anthropometric data, parameters of lipoprotein spectrum and carbohydrate metabolism were obtained from 115 men aged 34-67 years with hypertension. Hypertension combined with any other criterion of metabolic syndrome was associated with deviations of parameters of insulin resistance, blood pressure, body mass index, waist circumference, levels of cholesterol, low density lipoproteins and lipoprotein (a) similar to those observed in complete metabolic syndrome. Combinations of hypertension with hypercholesterolemia and/or excessive body mass were not associated with signs of insulin resistance in the presence of higher then in isolated hypertension values of body mass index, cholesterol, low density lipoprotein cholesterol.

[Physical exercise and atherosclerosis: dynamic high intensity exercise as a factor inducing exogenous dyslipidemia]. / Fizicheskie nagruzki i ateroskleroz: dinamicheskie fizicheskie nagruzki vysokoi intensivnosti kak faktor, indutsiruiushchii ékzogennuiu dislipidemiiu.

Effect of dynamic exercise of various intensity (maximal 100% and submaximal -- 80, 70 and 60% of individual maximally tolerated work load) on blood lipids, lipo- and apolipoproteins (apo) was studied in healthy subjects and patients with coronary heart disease. Both in healthy persons and patients high intensity (100 and 80%) exercise was associated with atherogenic changes of lipid transport system: increases of levels of total and low density lipoprotein cholesterol, triglycerides, apolipoprotein B and apo B/apo-A1 ratio. On the contrary, changes after exercise of moderate (60%) intensity (lowering of apo-B containing lipoproteins in healthy subjects and patients and elevation of apo-A1 concentration in healthy subjects) were antiatherogenic.

[Correction of atherogenic exogenously-induced postprandial hyperlipidemia with pravastatin]. / Pravastatin v korrektsii aterogennoi ékzogenno-indutsirovannoi postprandial'noi giperlipidemii.

Effect of an HMG-CoA reductase inhibitor pravastatin on atherogenic changes in the lipid transport system during postprandial hyperlipidemia immediately after ingestion of fatty meal was studied in patients with coronary heart disease and fasting hyperlipidemia. Treatment with pravastatin (20-40 mg/day for 3 months) resulted in normalization of fasting levels of blood lipids and decreased postprandial hyperlipidemia due to of enhanced removal of triglyceride-rich atherogenic lipoproteins from blood and their diminished secretion in response to fat load. Moreover pravastatin increased tolerance of the lipid-transport system to exogenous saturated fats. KEY WORDS. coronary heart disease; postprandial hyperlipidemia; pravastatin; lipoproteins, metabolism.

[The changes of lipids, lipoproteins and apolipoproteins in plasma in ischemic stroke]. / Izmenenie soderzhaniia lipidov, lipoproteinov i apolipoproteinov v plazme krovi pri ishemicheskom insul'te.

Contents of lipids (cholesterol CS, triglycerides) as well as levels of CS of lipoproteins of different density and of apolipoproteins A1 and B were measured in blood serum of 31 patients in different periods after of ischemic stroke. The majority of the indices studied were significantly decreased in men in acute periods of the stroke, especially in 8-21 days after the stroke development. Meanwhile, the levels of lipids, CS lipoproteins of both low and very low densities were increased later. Contents of CS of antiatherogenic lipoproteins of high density (HDLP) was low in different periods after the development of disorders of cerebral circulation. This confirms the concept that low level of HDLP is one of the risk factors of ischemic stroke. Decrease of the levels of both lipids and CS of lipoproteins of different density was more pronounced in patients with more severe atherosclerotic damages of the main cerebral arteries. Disorders of metabolism of lipoproteins in ischemic disorders of cerebral circulation are discussed with reference to literary data taking into consideration their heterogeneity. Genetically determined pathology of certain apolipoproteins plays a key role factor in the development of early atherosclerosis and in the elucidation of biochemical markers of the primary damages of cerebral vessels.

[The effect of micronized phenofibrate on the lipoproteins of the blood plasma at different initial lipid levels]. / Vliianie mikronizirovannogo fenofibrata na lipoproteidy plazmy krovi pri razlichnom iskhodnom urovne lipidov.

Novel antihyperlipidemic micronized phenofibrate lipantil 200 M was tested for safety and efficacy (one 200 mg capsule a day for 3 months) in 27 patients having cholesterol level above 6.5 mmol/l. The effect emerged upon 1 month of administration and persisted till the end of the treatment. In combined hyperlipidemia triglycerides decreased by 45-60%, total cholesterol and LDL cholesterol by 10-12%. In isolated hyperlipidemia the latter two values appeared lower by 20-23 and 22-27%, respectively. After lipantil 200 M treatment HDL cholesterol went up by 9% in low baseline level (< 1 mmol/l) by 27%. No negative clinico-biochemical shifts were seen, while fibrinogen and uric acid reduced by 16%, apoB by 23-30%. Lipantil 200 M proved active against hyperlipidemia and is recommended for clinical practice.

[The hypolipidemic effect of and tolerance for Lescol in treating hypercholesterolemia in hypertension patients (an analysis of the data from a multicenter study)]. / Gipolipidemicheskii éffekt i perenosimost' leskola pri lechenii giperkholesterinemii u bol'nykh gipertoniei (analiz dannykh mnogotsentrovogo issledovaniia).

Hypertensive patients with hyperlipidemia are at high risk to develop coronary heart disease (CHD). Chemotherapeutic correction of hyperlipidemia seems most reliable modality to prevent CHD. Hypolipidemic effect and tolerance of leskol (fluvastatin) in dietotherapy-resistant hypercholesterolemia were studied in 74 patients with essential hypertension treated with hypotensive drugs. The patients were included in a multicenter trial. A 12-week course reduced total cholesterol level under 6.2 mmol/l in 59% of the patients, under 5.2 mmol/l in 29% of them. LDLP cholesterol lowered to 3.5% in 34% of the patients. Mean apo B diminished by 23%. There was a 27% decrease in the proportion of atherogenic fraction apo B to antiatherogenic fraction of transport proteins apo A-I. Leskol is well tolerated and effective against hypercholesterolemia, it is safe in relation to side effects and blood biochemistry.

[The lipid transport system and its hormonal regulators in youths suffering from obesity]. / Sostoianie lipidtransportnoi sistemy i ee gormonal'nykh reguliatorov u iunoshei s ozhireniem.

The type and degree of changes in the lipid transporting system of blood plasma and levels of hormonal provision of the regulatory processes in juvenile obesity of different degrees were under study. A single fat food loading was used to detect the precursors or latent forms of disorders in lipoprotein spectrum and their hormone regulators. A total of 35 obese patients aged 16 to 18 and 30 age-matched healthy youths were examined. Analysis of the baseline values showed increased levels of apolipoprotein B, cholesterol, triglycerides, insulin, and reduced levels of apolipoprotein A1, high-density lipoprotein cholesterol in obese youths vs. controls. A atherogenic pattern of changes in the lipoprotein and apolipoprotein spectra of the plasma obese youths was clearly seen under conditions of fat food loading, these changes being associated with disordered insulin reaction to intake if exogenous fat. The examinees suffering from obesity a varying degree, mainly from the abdominal variant, presented with a complex of interrelated metabolic disorders (hyperinsulinemia, insulin resistance, dyslipoproteinemias),--the metabolic X syndrome, this referring them to a group at risk of developing atherosclerosis, essential hypertension, diabetes mellitus irrespective of the degree of general obesity.

[Changes in the blood lipoprotein and apolipoprotein spectrum and the state of coronary channel in patients with unstable angina pectoris: a follow-up]. / Dinamika spektra lipoproteidov, apolipoproteinov plazmy krovi i sostoianie koronarnogo rusla u bol'nykh s nestabil'noi stenokardiei pri dlitel'nom nabliudenii.

The study was undertaken to examine 34 male patients with unstable angina pectoris who underwent coronary angiography (in the period of instability and at rehospitalization) and study of protein and lipid parameters in their plasma. During a follow-up (mean 33.9-2.2 months), the patients were divided into 2 groups according to the changes occurring in the coronary bed. These included: (1) patients with progressive atherosclerotic changes and (2) those with stabilization of the process. Changes in the lipid profile in patients with unstable angina were found to appear as profound atherogenic shifts in the spectrum of lipoproteins and apolipoproteins, which suggests that coronary atherosclerosis is progressive in the late period.

[The effect of a diet enriched with omega-3 polyunsaturated fatty acids on thrombocyte functional activity and on the blood lipid-apolipoprotein spectrum in newly occurring stenocardia]. / Vliianie diety, obogashchennoi omega-3 polinenasyshchennymi zhirnymi kislotami, na funktsional'nuiu aktivnost' trombotsitov i lipidno-apolipoproteinovyi spektr krovi pri vpervye voznikshei stenokardii.

The diet enriched with omega-3 polyunsaturated fatty acids (5 g/day for 4 weeks) was applied to the treatment of patients (n-22) with angina pectoris occurring for the first time. Meanwhile 6 patients received the control diet similar to the fish one as regards the protein, fat, carbohydrate, cholesterol and caloric ratio. The control group patients showed no alterations in blood lipids and apoproteins of in platelet function. The patients who received the fish diet manifested an appreciable decrease in the concentration of triglycerides (p less than 0.01), a slight reduction of cholesterol content. The level of high density cholesterol remained unchanged. There was a decrease in the concentration of thromboxane (p less than 0.05) and in the platelet count (p less than 0.05). In some patients, individual reactions of ADP-induced platelet aggregation were revealed: from the lowering (-60-10%) seen in the third of the examined up to the rise (+10+90%) in the other third. The decrease of apoprotein A1 established as safe for the protective cholesterol-transport properties of high-density lipoproteins was established.

[Effect of nutrition factors on the subfractional spectrum of high density lipoproteins]. / Vliianie pishchevykh vozdeistvii na subfraktsionnyi spektr lipoproteidov vysokoi plotnosti.

High amount of animal lipids containing in a diet of 5 persons examined led to increase in content of lipids and of subfraction 3b of high density lipoproteins (HDL) as well as to decrease of the HDL 3a subfraction in their blood plasma. Hypocholesterolemic diet, used for medical purposes in 5 patients with heart ischemic disease within 4 weeks, caused the opposite alterations in the HDL subfraction spectrum of all the patients studied: a decrease in 3b subfraction and an increase in 3a subfraction content. Any alterations in the patterns studied, estimated every week, were not observed in the control group (5 persons) maintained on usual diet without certain dietetic or medical recommendations. These alterations in the HDL subfraction spectrum, observed under conditions of various diets, appear to occur due to their dissimilar effects on alternative steps of cholesterol transport: in loading with lipids--impairment of usual catabolism of HDL2 particles, which, after carrying out of their functions, are remained in circulation and converted into HDL3-like particles. In hypocholesterolemic diet specific pool appears to be available in turnover of small particles into large fractions (conversion of 3a into 2a subfractions). Thus, short-term lipid loading as well as prolonged diet free of animal lipids, usually occurring in human life, affect the transport system of cholesterol elimination from peripheric tissues, which was manifested as alteration in the subfraction spectrum of HDL.

[Newly developed stenocardia: effect of intensive physical training on the lipoprotein spectrum of blood plasma]. / Vpervye voznikshaia stenokardia: vliianie intensivnykh fizicheskikh trenirovok na lipoproteidnyi spektr plazmy krovi.

The effect of intensive exercise (IE) on plasma lipoproteins was assessed in patients with angina of new onset (first three months). A six-week IE course increased stress tolerance. Total cholesterol (CS), triglycerides (TG), low-density lipoprotein cholesterol (LDLP CS) levels dropped significantly. High-density lipoprotein cholesterol (HDLP CS) remained unchanged, yet the total CS-HDLP CS/HDLP CS ratio dropped significantly after 6 weeks of training, with total CS, TG and the total CS-HDLP CS/HDLP CS ratio already decreasing significantly within 2 weeks. After six weeks of exercise, apo-B level remained unchanged, apo-AI level rose significantly, and the apo-B/apo-AI ratio decreased significantly. Positive shifts in plasma lipid and apoprotein spectrum resulted in a decrease of lipoprotein atherogenic characteristics.