Quantitative evaluation of gene variation and interpopulation differentiation of parthenogenetic species of Darevskia lizards based on mini- and microsatellite DNA markers

Methods of estimating within- and between-population gene diversity in parthenogenetic species using mini- and microsatellite DNA markers and modified Wright's FST statistic are presented with special reference to model populations of lizards of the genus Darevskia (D. dahli, D. armeniaca, D. unisexualis). We used DNA fingerprinting data for several populations of these species examined earlier. The effects of variation in M13, minisatellite, (GACA)n and (TCC)n microsatellite loci on the formation of within-population gene diversity in parthenogenetic species D. dahli and D. armeniaca were shown to be different. The equality of the realized gene diversity H and its maximum possible value Hmax in two populations of D. dahli (Hmax = 0.032, H = 0.031, P < < 0.0431; Hmax = 0.024, H = 0.027, P = 0.09) and D. armeniaca (Hmax = 0.05, H = 0.053, P = 0.03; Hmax = 0.054, H = 0.055, P = 0.02) suggests that variation in (GACA)n loci substantially contributes to the maintenance of within-population genetic diversity. Analysis of between-population genetic diversity using loci M13, (GACA)n, and (TCC)n showed differentiation of D. dahli populations from northeastern and northwestern Armenia (FST = 0.0272, P = 3 x 10(-13)) and genetic homogeneity of the Armenian and Introduced to the Ukraine populations of D. armeniaca characteristic of one clone (FST = 0, P = 1).     

Prevention of infectious complications in patients with acute bone marrow depression]

Clinical efficacy of intravenous gentamicin in combination with oral use of gentamicin, ristomycin and nystatin was studied in 1977. In 1980-1984 two antiinfectious regimens were tested: intravenous administration of gentamicin in combination with total decontamination (oral use of gentamicin and nystatin) and selective decontamination (biseptol with nystatin of amphoglucamine). It was shown that the incidence of severe infections in the patients under the observation dropped against the controls. The incidence and spectrum of infectious complications in cases with acute myelodepressions were proved to depend on the intestinal autoflora inhibition.     

Recovery of instrumental conditional reflexes in rats after pyramidotomy and action of bacterial melanin

Unilateral pyramidotomy at the bulbar level performed after preliminary elaboration of instrumental conditional reflex (ICR) and without its elaboration caused hemiparesis of extremities in rats. Next day after this operation a half of the operated animals both with elaborated ICE and without its elaboration was injected intramuscularly with bacterial melanin solution (170 mg/kg). Comparison of terms of recovery of ICR and of a balancing movement of the paralyzed hindleg in the operated rats without administration of melanin and with its injection showed that in the "melanin" animals the time of posttraumatic rehabilitation was much shorter and recovery of movement occurred faster and more completely. It has been found that the difference in terms of recovery of rat motor functions in this case is due to the protector action of bacterial melanin.     

The effect of various methods of preserving the fungus Aspergillus niger v. Tighem on its aggressive properties

Using the differential-thermic and thermogravimetric methods has shown that the most promising way of fungus Aspergillus niger storing when its aggressive properties against polyamid aren't lost is to keep the culture on polymeric matter (polyamid) and in soil.     

Taurine as a universal carrier of lipid soluble vitamins: a hypothesis

Summary. In the literature taurine is characterized as a non-specific growth or blood clotting factor, an antioxidant, a membrane protector, or a regulator of calcium ion homeostasis, just as vitamins A, D, E, F, and K are similarly characterized. On the basis of recent finding concerning the relationship between taurine and the aldehyde of vitamin A-retinal (Petrosian and Haroutounian, 1988, 1998; Petrosian et al., 1996), as well as on the basis of data from the literature, we now suggest a hypothesis that taurine promotes the bioavailability of the lipid soluble vitamins A, D, E, K, and F, probably by forming different types of water soluble, easily hydrolyzable complexes. It is quite possible that the ability of taurine to convert lipids and lipid soluble substances into a water soluble state is the key to understanding the unusually wide diversity of biological phenomena associated with taurine. This form of delivery may be an additional, secondary mechanism for the transport of lipid soluble vitamins, which was probably acquired early in evolution, and remains extremely important for mammals and humans directly after birth for a variety of physiological functions such as: vision in normal and in emergency situations, rapid blood clotting, sperm eruption, and situations requiring a prompt consumption of lipid soluble vitamins characteristic of excitable systems. Clearly, the role of taurine in the physiology of the water insoluble vitamins remains an enigma and is worthy of further investigations. Received December 23, 1999; Accepted December 28, 1999     

Variation of mini- and microsatellite DNA markers in populations of parthenogenetic rock lizard Darevskia rostombekovi

Variation and clonal diversity in populations of the parthenogenetic rock lizard Darevskia rostombekovi was examined by means of multilocus DNA fingerprinting using mini- and microsatellite DNA markers M13, (GATA)4, and (TCC)50). The animals examined were shown to exhibit a clonally inherited, species-specific pattern of DNA markers (fingerprint profile) that is different from the species-specific patterns of parthenogenetic species D. dahli, D. armeniaca, and D. unisexualis. The mean intraspecific similarity index S was 0.950 (0.003) for a sample of 19 animals from three isolated populations of North Armenia. This significantly differed from the estimate of this parameter for a sample of 21 animals including two individuals from mountainous, relict population from the vicinity of the Sevan Lake, which was equal to 0.875 (0.001). A comparison of DNA fingerprints showed differences between 21 individuals attaining 79 DNA fragments of 1801 mini- and microsatellite markers included in the analysis. The results obtained show that intraspecific variation in D. rostombekovi is higher than that in the previously studied parthenogenetic species D. dahli (S = 0.962) and D. unisexualis (S = 0.950) (P < 0.001). Taking into account that D. rostombekovi is considered monoclonal on the basis of allozyme data, the problem of clonal variability is discussed with regard to the evidence on nuclear DNA markers. It is suggested that the hybrid karyotype of D. rostombekovi, which is more unstable than that of D. dahli and D. unisexualis, generates a series of chromosomal rearrangements (mutations). This may lead to the appearance of a geographically isolated chromosomal race (clone) in the population inhabiting the southeastern coast of the Sevan Lake.