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Chromosomal DNA in 5 hereditary variants occurring in Photobacterium leiognathi population was subjected to restriction analysis. The variants differed in the levels and regulation of luminescence and colony morphology. Agarose electrophoresis of DNA fragments isolated after exposure to Hind II, Bam HI, Bgl I and Pst I restriction endonucleases revealed respectively 38, 28, 35 and 29 fragments equally distributed by their molecular weights. Electrophoregrams of the 5 strains were absolutely identical. After exposure of DNA of all the strains to PVu II, Xho II, Sal GI and Eco RI restriction endonucleases there were detected no fragments. The pleoiotropic genetic variation in these strains was not associated with large deletions or amplification of chromosomal DNA regions.

Variations in the intensity of luminescence of Photobacterium belozerskii grown on different media were studied. In the course of growth the luminescence intensity changed by 2 to 4 orders of magnitude, depending on the nutrient medium used. Exogenous myristic aldehyde added to the bacterial suspension at the time of luminescence measurement decreased the intensity to a degree, which was essentially independent from the initial level. The onset of an increase in the luminescence intensity depended on the nutrient medium. An addition of arginine, proline or asparagine to the medium reduced the latent period and simultaneously increased the luminescent intensity by 30, 10 and 5-10 times, respectively. Arginine and proline added to the minimal medium at the time of an increase in the luminescence of P. belozerskii enhanced the rate of biosynthesis of the luminescent system enzymes by 32 and 10 times, respectively. In response to a combined action of these amino acis, the rate of luciferase biosynthesis grew by 630 times. Possible mechanisms and factors responsible for the above changes are discussed.

The authors studied the relationship between the functional activity of the adrenal cortex before and after the ACTH administration and the thymus mass in AKR, C57BL/6, C3H/He, and C3Hf mice. Blood 11-OCS level of these mice proved to differ in accordance with the differences in the 11-OCS production by the adrenal glands. There was revealed no expected inverse correlative dependence between the basal blood glucocorticoid content and the thymus mass. After ACTH administration the mouse species could be placed thus in order of increasing reaction of the thymus: AKR less than C3Hf less than C3H/He less than C57BL/6; this correlated positively with the level of 11-OCS production by the adrenal glands and basal 11-OCS concentration in the peripheral blood.

Relative thymus weight was estimated in C3H/He, C57BL/6 mice, their F1 and backcross hybrids, as well as in the progeny of complete diallel crosses between the BALB/c, C3H/He, C57BL/6 and AKR/J strains. On the basis of the analysis of these measurements, a conclusion is drawn that this character is inherited with incomplete dominance of smaller relative weight. The genes determining greater thymus weight are concentrated in the genetic pool of AKR/J and C57BL/6 strains. These genes are characterized by some degree of recessivity with respect to the genes determining smaller thymus weight which are concentrated in the genetic pool of C3H/He and BALB/c strains. The highest concentration of the "plus" and "minus" genes is found in the genetic pools of AKR/J and C3H/He strains respectively.

The effect of cAMP on the parameters characterizing the development of luminescence in Photobacterium belozerskii is discussed. An addition of cAMP to the culture medium shortened the latent time of luminescence development by 3--6 hours. The intensity of bacterial luminescence increased with a varying rate. During luminescence enhancement the rate of luciferase synthesis increased by a factor of 10 to 10(3). The rate of luciferase synthesis and the maxiumum level of bacterial luminescence when cultivated in the glycerol medium containing arginine and proline increased under the influence of cAMP by 100 and 40 times, respectively. After an addition to cAMP into the glucose medium these parameters of luminescence development increased only when the medium contained arginine. After an addition of cAMP into the glycerol medium the rate of bacterial growth increased two-fold. Possible mechanisms regulating luminescence development and cAMP involvement in these processes are discussed.