No abstract

The review deals with features of sex determination in vertebrates. The mechanisms of sex determination are compared between fishes, amphibians, reptilians, birds, and mammals. We focus on structural and functional differences in the role of sex-determining genes in different vertebrates. Special attention is paid to the role of estrogens in sex determination in nonmammalian vertebrates.

To study the role of telomere (TTAGGG)(n) sequences in promoting of crossing over in chicken female meiosis, we have localized telomere repeats by FISH and studied the distribution of chiasmata in the giant diplotene bivalents, the chicken lampbrush macrochromosomes 1--3. We show that all interstitial clusters of the (TTAGGG)(n) repeat in these chromosomes do not coincide with hot spots of genetic recombination (crossing over) in the chicken female. Moreover, terminal TTAGGG-positive chromomeres also are not chiasma hot spots. We conclude that, at least in chicken macrochromosomes in female meiosis, a role for canonical telomere sequences in promoting of crossing over is not confirmed.

Chiasmata in diplotene bivalents are located at the points of physical exchange (crossing-over) between homologous chromosomes. We have studied chiasma distribution within chicken lampbrush chromosome 1 to estimate the crossing-over frequency between chromosome landmarks. The position of the centromere and chromosome region 1q3.3-1q3.6 on lampbrush chromosome 1 were determined by comparative physical mapping of the TTAGGG repeats in the chicken mitotic and lampbrush chromosomes. The comparison of the chiasma (=crossing over)-based genetic distances on chicken chromosome 1 with the genetic linkage map obtained in genetic experiments showed that current genetic distances estimated by the high-resolution genetic mapping of the East Lansing, Compton, and Wageningen chicken reference populations are 1.2-1.9 times longer than those based on chiasma counts. Conceivable reasons for this discrepancy are discussed.

The physicochemical properties of water activated by high-purity low-temperature argon plasma of electrodeless microwave discharge at atmospheric pressure are investigated. Such parameters of activated water as electrical conductivity, redox potential, hydrogen index (pH), the concentrations of dissolved molecular oxygen, hydrogen peroxide, OH-radicals, nitrate and nitrite anions depending on the plasma jet distance above the water surface and duration of activation were studied. Under irradiation conditions close to optimum, it was shown that the generation rate in the absence of impurities are 200 μM/min for H2O2; 800 μM/min for •OH and 2 mM/min for NOx−. The use of plasma activated water (PAW) in agriculture has been tested. It was shown that strawberry seeds treated with a surfactant solution grow much faster than control seeds. The mechanisms of the chemical composition formation of activated water and its biological properties are discussed.