Determination of Azospirillum brasilense cells with bacteriophages by electrooptical analysis of microbial suspensions

The dependence of changes in the electrooptical properties of Azospirillum brasilense cell suspension Sp7 during interaction with bacteriophage ΦAb-Sp7 on the number and time of interactions was studied. Incubation of cells with bacteriophage significantly changed the electrooptical signal within one minute. The selective effect of bacteriophage ΦAb on 18 strains of bacteria of the genus Azospirillum was studied: A. amazonense Am1i4, A. brasilense Sp7, Cd, Spl07, Sp245, Jm6B2, Brl4, KR77, S17, S27, SR55, SR75, A. halopraeferans Au4, A. irakense KBC1, KA3, A. lipoferum Sp59b, SR65 and RG20a. We determined the limit of reliable determination of microbial cells infected with bacteriophage: ∼10⁴cells/mL. The presence of foreign cell cultures of E. coli B-878 and E. coli XL-1 did not complicate the detection of A brasilense Sp7 cells with the use of bacteriophage ΦAb-Sp7. The results demonstrated that bacteriophage ΦAb-Sp7 can be used for the detection of Azospirillum microbial cells by the electrooptical analysis of cell suspensions.