[Development and application of indirect competitive enzyme immunoassay for detection of neomycin in milk].

As a result of immunization of rabbits with neomycin B (N M) conjugated to periodate-oxidized transferrin, polyclonal antibodies were generated and used to develop an indirect competitive enzyme-linked immunosorbent assay (ELISA) of NM. Several heterologous conjugates, namely, glutaraldehyde (GA)-polymerized NM, gelatin-ribostamycin (sp), and gelatin-NM (ga) were used as coating antigens in different ELISA variants for quantification of NM in milk. These variants were characterized by different dynamic ranges and detection limits of 1.

[Monoclonal antibody based enzyme-linked immunosorbent assay for aminoglycoside antibiotic kanamycin in foodstuff].

Monoclonal antibodies to aminoglycoside antibiotic kanamycin (KM) were raised as a result of mice complex immunization with glutaraldehyde conjugates BSA with KM, tobramycin (TM) and gentamicin. Using antibodies an indirect competitive enzyme-linked immunosorbent assay was developed. This method allows to determine antibiotic up to 1.

[Identification of heterologous antitoxin in sera of patients with diphtheria].

Using immobilized diphtheria toxin and peroxidase conjugate of monoclonal antibodies to light chains of equine immunoglobulin a method of quantification of equine antibodies against diphtheria in sera of patients after serotherapy was developed. The sensitivity of indirect enzyme-linked immunosorbent assay was 0.0005 IU/ml, and coefficient of variation did not exceed 10%.

[Study of diphtheria anatoxins in immunochemical and tissue culture assays].

Equine diphtheria antitoxins from different manufacturers were studied. Their immunochemical interaction with diphtheria toxin, toxoid, and antigens of Corynebacterium diphtheriae in ELISA and immunoblotting assays as well as biological activity in CHO cell assay were compared. The discovered differences between antitoxin samples with stated equal activity in IU/ml point to heterogeneity of antigen composition in preparations used for immunization.

[Use of monoclonal antibodies against horse immunoglobulin in an enzyme immunoassay of bacterial toxins and anatoxins].

Immunization of BALB/c mice by horse antiserum against diphtheria made it possible to obtain IgG1 monoclonal antibodies (MoAbs) 2B7E4 specific for light chains of horse immunoglobulin (Ig). Unlike commercial preparations of anti-horse immunoglobulin antibodies, which are specific for the whole Ig molecule or its Fc-fragment, the peroxidase (HRP) conjugate of the MoAb, 2B7E4-HRP did not interact with human, mouse, rabbit, and sheep Igs, or horse albumin. The conjugate obtained was used with MoAbs against bacterial toxins and commercial horse anatoxins, as a universal reagent in sandwich enzyme immunoassay (ELISA) for bacterial toxins and anatoxins.

[Choice and selection of a Staphylococcus saprophyticus strain--a urease producer].

A new strain of Staphylococcus saprophyticus was isolated from natural sources. The strain has a higher activity of urease comparing to other cultures producing the enzyme. The strain is referred to as S.

[Urease biosynthesis and isolation in Staphylococcus saprophyticus L-1].

Experiments were carried out to investigate the effect of organic components of the medium and cultivation conditions on the multiplication rate and urease biosynthesis by Staphylococcus saprophyticus L-1 cells isolated from natural sources. The yeast enzymic hydrolyzate and corn extract were found to be an adequate substitute for the costly organic components--peptone and yeast extract. The substitutes ensured a high level of urease biosynthesis and biomass accumulation.

[Urease synthesis regulation in Staphylococcus saprophyticus by urea and ammonia].

The effect of growth conditions on urease synthesis was studied with Staphylococcus saprophyticus L-1 isolated from natural sources. Urease biosynthesis was recorded in the absence of urea in the complete medium and in the conditions of nitrogen deficiency; the highest level of the enzyme biosynthesis was found when the culture was grown in the absence of amine nitrogen in the medium. Ammonium ions were a reversible inhibitor of urease and, at a high concentration (30 g of (NH4)2SO4 per litre of the medium), partly repressed its biosynthesis.