Biomedical subjects

S N Lavrovskiĭ

Publications and source records attributed to S N Lavrovskiĭ.

5 recordsLinked to original sources

PubMedDate not supplied

[Catalytic properties of neuraminidase of non-cholera vibrios].

Main catalytic properties of commercially available neuraminidase preparations from noncholeric vibrios were studied. The enzymatic activity was measured using a simple resorcinol procedure. Optimal conditions for neuraminidase effect: pH 5.5-6.0 and buffer composition, were characterized. Affinity of the enzyme to various substrates was studied using 10 natural and synthetic sialoconjugates. Km values were studied for fetuin, ovomucin and transferrin used as optimal substrates. When influence of meta ions, detergents, complexes and other compounds was studied, activation of neuraminidase was found in presence of bivalent metal ions, especially of Ca2+, while chelate-forming complexes and heavy metal salts inhibited the enzyme. These results may be used in studies of the neuraminidase action mechanism and regulation of its activity.

Catalysis↗

PubMedDate not supplied

[Characteristics of various physico-chemical properties of vibrion neuraminidase].

Some physico-chemical properties of commercially available neuraminidase preparations from non-choleric vibrio were studied. The neuraminidase was shown to be weakly acid glycoprotein with molecular mass 90 +/- 5 kDa, sedimentation constant 5.37 S and pI 5.0 +/- 0.1. As shown by roentgen-diffractometric technique the neuraminidase preparations possessed a quasi-crystalline structure. All the preparations studied were highly purified, exhibited electrophoretic homogeneity, did not contain any protein and Me+ contaminations.

Chromatography, Gel↗

PubMedDate not supplied

[Immunochemical characteristics of vibrio neuraminidases isolated from aerated culture filtrates].

Immunochemical analysis of neuraminidases, isolated from choleraic and non-choleraic vibrios, was carried out. Antineuraminidase antiserum was used in procedures of immunoelectrophoresis, diffusion precipitation in agar gel and disc immunoelectrophoresis in polyacrylamide gel. Antigen composition of neuraminidases was shown to be similar both in choleraic and non-choleraic vibrios.

Bacteriological Techniques↗

PubMedDate not supplied

[Measuring neuraminidase activity by the thiobarbiturate method].

A number of reducing agents used for removing the excess of periodate in the reaction of the neuraminidase (EC 3.2.1.18) activity measuring by the thiobarbituric acid technique were compared. The toxic reagent sodium arsenite may be replaced by a 20% solution of ascorbic acid. The modified technique of the neuraminidase activity determining can be used in case of both high-molecular weight substrate ovomucin and low-molecular weight substrate-glycomacropeptide from milk whey.

Indicators and Reagents↗

PubMedDate not supplied

[Cerebral lactate dehydrogenase isoenzymes in different hypoxic conditions].

Spectrum of LDH isozymes and their activity were compared in animal brain tissue under circulatory and hypoxic forms of hypoxia. Dynamics and manifestation of alterations observed correlated primarily with the type of oxygen deficiency as well as with its severity and length of action. Development of oxygen deficiency in brain tissue was accompanied by increase in total LDH activity and by elevation in content of M-subunits, typical for "anaerobic" spectrum of LDH isozymes, with simultaneous decrease in amount of H-subunits.

Altitude Sickness↗