[Changes in electrophysical characteristics of Azospirillum brasilense Sp7 cells during their interaction with polyclonal antibodies].

Electrooptical characteristics of Azospirillum brasilense Sp7 cells during their specific interaction with polyclonal rabbit antibodies were studied. Dependence of optical density of cell suspension during electroorientation of cells from frequency of orienting field in interval 10, 100, 250, and 500 kHz was evaluated. Itwas shown that electrooptical (EO) characteristics of bacterial suspensions change during interaction of A.

[The electrooptical parameters of suspensions of Escherichia coli XL-1 cells interacting with helper phage M13K07].

The electrophysical properties of Escherichia coli XL-1 cells interacting with helper phage M13K07 were studied as a function of the phage-to-cell ratio and the contact time. The electro-optical signal of bacterial cells changed considerably as soon as 10 min after the onset of their incubation with phage particles, presumably due to phage adsorption on the cell surface. The maximum changes in the orientational spectra of cell suspensions were observed when the phage-to-cell ratio was 20.

[Investigation of electrophysical properties of Listeria monocytogenes cells during the interaction with monoclonal antibodies].

An electrooptical approach was used in studies of Listeria monocytogenes-antibody binding. An electrooptical analyzer, which has been developed at the State Research Center for Applied Microbiology (Obolensk, Russia), was used as a basic instrument for electrooptical measurements. The analyzer consists of the following modules: a sample preparation module, a mixer, an AC field generator, an EO-flow cell, a microcontroller for transfer of liquid, a thermal system, an operator interface, and an image processor.

[A highly sensitive immunoenzyme analysis using electrochemical detection].

The authors have developed a method for improving the sensitivity of electrochemical enzyme immunoassay, based on binding the enzymatic reaction volatile component to a complexone, followed by destruction of the complex in a flow-type amperometric detector. The lowest limit of the measured levels of blood serum antibodies and antigens is 10(-11)-10(-12) M. The method was tried in enzyme immunoassay of the blood serum IgE in patients with asthma and chronic obstructive bronchitis.

[An electrochemical method of determining peroxidase in saliva].

Electrochemical method has been developed for measuring human salivary peroxidase. Salivary peroxidase levels were measured in donors in various hours of the day, in girls in various periods of the cycle, and in myocardial infarction patients. The results may be used to develop rapid methods for assessment of ovarian functional activity and for prediction of myocardial infarction outcome.

[Immunochemical study of modified forms of L-asparaginase].

Certain catalytic and immunological properties of L-asparaginase modified by polyglucin were studied. It was shown that the modified forms of L-asparaginase maintained high catalytic activity (Km 0.80.

[Determining the peroxidase level using tubular coal electrodes in flow-type systems].

An amperometric transducer with tubular coal electrodes has been worked out to determine the microquantity of peroxidase. The hydrodynamic parameters of the transducer were studied as were the relationship of the output signal to the concentration of the electroactive substance, the length of the electrode, the speed of the background electrolyte movement and the diffusion coefficient. The line section of the relationship between the strength of current and the peroxidase concentration is observed within the interval of the enzymic concentration 1-32 ng/ml with the exposure time of the enzymic reaction of 5-10 min.

[Amperometric sensor for recording the results of immunoenzyme analysis].

A technique for quantitative determining horseradish peroxidase was developed using an amperometric sensor that makes it possible to register up to 50 pM of the enzyme in the reaction of the peroxidase oxidation of iodide ions by hydrogen peroxide. The sensor, composed of combined carbon and Ag/AgCl electrodes, is intended for enzyme immunoassay and may be used for registering the results in the very wells of the polystyrene plates widely used in clinics and laboratories. The dependences of the initial rate of the enzymatic reaction on the substrate concentration and pH of the medium were determined, on the basis of which the conditions for the optimal operation of the sensor were found.