[Simple and rapid heterologous method of radioimmunochemical determination of luteinizing hormone in the blood serum of rats. 1. Basic principles of the method]

Possibilities of creation of a radioimmunochemical method (RICM) of determination of the luteinising hormone (LH) were studied. The method is based on the application in the binding system of a water-insoluble immunosorbent obtained by copolymerization of antisera with isobutyl ester of chlorocarbonic acid. The antisera were obtained by immunization of rabbits with a highly-purified LH isolated from sheep hypophyses. The method is rapid and precise, and is carried out in a single stage. Significant results of RICM in the LH determination can be obtained with the minimal two-hour incubation time. Using different amounts of the immunosorbent in the reaction mixture with the same indicator dose of I125-LH it is possible to vary the method sensitivity (from 0.05 to 5 ng/test).

[A method of comparison of DNA polynucleotide sequences]

The results of a comparative analysis of the kinetic curves of reassociation of DNA of closely related species of Microtus (Microtus arvalis, Microtus oeconomus oeconomus, Microtus oeconomus Chachlovi) are presented. A five power polynomial was used as a mathematical model of the kinetic DNA reassociation curves. The values of polynomial coefficients and the theoretical value, both with statistical deviations dispersion, have been estimated with the help of a standard computer programme. The modified Fischer criterium was used for comparing the model kinetic curves of reassociation of the above species and of subspecies of Microtus, and to estimate the significance of the difference between two random means. A pair-wise comparison of the model curves shows that the similarity of the DNA polynucleotide sequences in two subspecies is less expressed than in two species of Microtus. A method of comparison of DNA nucleotide sequences is suggested on the basis of mathematical models of kinetic curves of DNA reassociation.

[More precise identification of the systematic position of marine bacteria by the method of DNA-DNA hybridization]

In the present work by the method of molecular DNA hybridization there was shown a low degree of affinity of the standard museum strains of cholera vibrios to the respresentatives of the sea species V. parahaemolyticus and V. alginolyticus, and also halophilic vibrios identified earlier on the basis of phenotypical characteristics of the nucleotide DNA composition as Marinovibrio. The presence of only 20--30% of homology in the DNA successiveness in cholera vibrios and the mentioned sea bacteria pointed to the necessity of exclusion of the latter from the Vibrio genus.