Application of free-flow electrophoresis for isolation and purification of proteins and peptides

Free-flow electrophoresis (FFE) has been applied to the separation and purification of a variety of proteins and polypeptides: bee venom, tumor necrosis factor, interleukin-1beta, interferon-gamma and superoxide dismutase. FFE at constant pH and conductivity of the carrying buffer is shown to be efficient at various separation schemes. In some cases, the method allows us to obtain proteins with a purity of more than 90% at a productivity of 20-30 mg/h. An electrophoretic apparatus with a new, multi-sectional construction of the electrophoretic chamber and a system for cross-displacement of carrying buffer in the chamber is described.     

Hygienic assessment of indicators of the nutritional status of Monchegorsk school children

Diets, energy expenditures, physical and mental performance, anthropometric indices, ascorbic acid excretion, and morbidity rates were studied in 7-9-year-old schoolchildren of Monchegorsk, Murmansk Region. The alimentary features found served as the basis for developing sanitary recommendations to optimize diets and to promote children's health.     

Metrological analysis of measuring systems in testing an anticipatory reaction to the position of a moving object

This study compared the effects of angiotensin converting enzyme (ACE) inhibitors captopril versus enalapril on left ventricular (LV) muscle mass and LV systolic and diastolic function in 58 patients with primary glomerulonephritis and moderate chronic renal failure. The design was a 6-8 week titration phase and 6-month maintenance phase. Mean myocardial mass calculated by M-mode echocardiography in the captopril group was 153 +/- 26 g/m2 before, and 130 +/- 14 g/m2 after 6 months of treatment, in enalapril group 147 +/- 22 g/m2 before, and 126 +/- 23 g/m2 after 6 months of treatment (p < 0.05). LV ejection fraction, early and late transmitral flow velocities and early to late LV inflow velocities ratio were not significantly affected by both ACE inhibitors.     

The wzz (cld) protein in Escherichia coli: amino acid sequence variation determines O-antigen chain length specificity

The O antigen is a polymer with a repeated unit. The chain length in most Escherichia coli strains has a modal value of 10 to 18 O units, but other strains have higher or lower modal values. wzz (cld/rol) mutants have a random chain length distribution, showing that the modal distribution is determined by the Wzz protein. Cloned wzz genes from E. coli strains with short (7 to 16), intermediate (10 to 18), and long (16 to 25) modal chain lengths were transferred to a model system, and their effects on O111 antigen were studied. The O111 chain length closely resembled that of the parent strains. We present data based on the construction of chimeric wzz genes and site-directed mutagenesis of the wzz gene to show that the modal value of O-antigen chain length of E. coli O1, O2, O7, and O157 strains can be changed by specific amino acid substitutions in wzz. It is concluded that the O-antigen chain length heterogeneity in E. coli strains is the result of amino acid sequence variation of the Wzz protein.     

Functional stereotaxy with magnetic resonance tomographic guidance

The paper summarizes experience with stereotactic operations by magnetic resonance imaging data by using a Russian OREOL stereotactic manipulator. It describes methods of preoperative preparation of patients by employing diagnostic magnetic resonance tomographs. A number of points of the procedure for identification and localization of deep target structures from magnetic resonance images in parkinsonism, temporal epilepsy and some mental disorders.     

Specific substrates for spectrophotometric determination of penicillin acylase activity

Penicillin acylase substrates suitable for colorimetric determination of the enzyme activity have been tested in this study. The kinetic parameters (Km and kcat) have been elucidated for the following nine substrates: six phenylacetic acid derivatives (p-nitroanilide, p-nitrophenyl ester, p-nitro-m-carboxyanilide, p-nitro-o-carboxyanilide, p-nitro-o-hydroxyanilide, m-nitro-p-carboxyanilide), two D-phenylglycine derivatives (p-nitroanilide, p-nitro-m-carboxyanilide), and also p-nitrophenyl ester of acetic acid (p-nitrophenyl acetate). With the exception of p-nitrophenyl acetate, all the compounds studied are highly specific chromogenic substrates for penicillin acylase, but their reactivity is very variable and kcat/Km values are in a range from 0.8.10(4) to 5.10(6) M(-1).sec(-1).     

Reduction of acyloxyacyl hydrolase activity in circulating neutrophils from cows after parturition

Bovine neutrophils contain the enzyme acyloxyacyl hydrolase, which hydrolyzes the acyloxyacyl linkage of the two nonhydroxylated fatty acyl chains to two 3-hydroxy fatty acids in the highly conserved lipid A part of endotoxins with high specificity. This hydrolysis decreases the toxicity of lipid A, but the immunostimulatory capacity of endotoxins is largely maintained. In two trials, we studied the activity of acyloxyacyl hydrolase in neutrophils that had been isolated from the blood of 18 dairy cows around parturition. Between 10 and 26 d after parturition, the activity of acyloxyacyl hydrolase in neutrophils decreased approximately 20% below prepartum activity. At about 2 mo after parturition, acyloxyacyl hydrolase activity returned to prepartum values. Changes in acyloxyacyl hydrolase activity could not be attributed to changes in binding of lipopolysaccharides by the CD14 molecules on neutrophils or monocytes. We hypothesize that decreased acyloxyacyl hydrolase activity in neutrophils shortly after parturition is a factor that increases the susceptibility of dairy cows to coliform mastitis during early lactation.