Fractionation of eukaryotic DNA in a pulsating electrical field. I. Detection and properties of discrete DNA fragments]

The fractionation of eukaryotic DNA by field inversion gel electrophoresis results in the appearance of discrete DNA-fragments. The set of these fragments is similar to that of different eukaryotic representatives and consists of various chromosomal DNAs, unified by size. The physical properties of DNA-fragments suggest that they can form multimeric structures due to the presence of sticky ends flanking discrete fragments. We suppose that the set of discrete DNA-fragments results in a specific cleavage of intact nuclear DNA and can reflect different levels of chromatin structural organization.     

Effects of Temperature on Viability of Pathogenic Fusarium Species

The viability of three species of Fusarium pathogenic to winter cereals was differently affected by temperature. F. culmorum survived in vitro in soil for 4 months at 8, 20 and 30 °C, the number of colony forming units (CFU) recorded at these temperatures after incubation being 125, 185 and 624 % respectively when compared with the number present at the beginning of the experiment. F. avenaceum and F. heterosporum barely survived at 8 °C after incubation for 4 months but at 20 °C the numbers of CFU were 314 and 380 % respectively, while at 30 °C the corresponding number tor each of these species was 200 %.
At natural soil temperatures in winter, the number of CFU of F. culmorum after 4.5 months decreased to 60, 70 and 87 % of the number present at the beginning of this experiment when infested soil was buried at depths of 7–10, 15—20 and 30 cm respectively. In the upper soil layer where winter temperatures were lowest, survival of F. avenaceum and F. heterosporum did not occur. Survival rates for these two species at a depth of 15—20 cm were 20 and 5 % respectively. In the deepest layer of soil (30 cm) survival of these two species was 30 % for F. avenaceum and 10 % for F. heterosporum of the number present at the beginning of this experiment.
These results demonstrate that during the early spring stages of growth of winter wheat, inoculum of F. culmorum , unlike that of F. avenaceum and F. heterosporum , is also a source of infection in the top soil layer in our climatic conditions.     

Reproduction systems of representatives of the genus Rosa L. under conditions of continental climate

The features of reproductive biology of rose plants from the sections Caninae Crep., Indocae Thory, Cinnamomae DC., Synstylae DC. were studied by cytological methods and with the help of scanning electron microscopy for many years. The results obtained are reported.     

Is the Khanka Sawbelly <Emphasis Type=Italic>Hemiculter lucidus</Emphasis> (Cyprinidae) able to reproduce by gynogenesis?

The Khanka Sawbelly Hemiculter lucidus is characterized by a significant prevalence of females in catches of mature fish. By means of RAPD-analysis using 12 primers and karyological investigations, the assumption on the presence of a unisexual gynogenetic form in this species was checked. With consideration of the obtained data, the assumption on gynogenetic reproduction is rejected. Other causes of the shift in sex ratio towards females are discussed.     

Morphology of the antennal sensory cone in insect larvae from various orders

This article describes the morphology of antennae in larvae of three species of beetles from the families Cerambycidae and Chrysomelidae; one species of the caddis fly from the family Limnephilidae; and four species of dipterans from the families Culicidae, Chironomidae, and Muscidae. In all investigated species, the antenna has a sensory cone on it. Larvae of the caddis fly, longhorn beetles, and leaf beetles have on their antenna solitary sensillae and the sensory cone. This proves the advanced evolution of these species. Despite reduction of the head capsule, the antennal sensory cone in ±9/58 larvae of higher dipterans has become the dominant sensory structure.     

An experiment with a 105-day isolation simulating some conditions of a space flight to mars: the goals, scope, and structure of the research

The article deals with the main goals, objectives, and features of a 105-day experiment simulating some conditions of a manned space flight to Mars. It contains the scope and time patterns of the research program of the 105-day experiment, as well as methodological and organizational recommendations for the preparation for a 520-day experiment based on the analysis of the results of a 105-day experiment.     

The validation of specific status of the sakhalin sturgeon <Emphasis Type="Italic">Acipenser mikadoi</Emphasis> (Acipenseridae) in the light of recent genetic and morphological data

The comparative morphological study in different Acipenseriform species demonstrates that there are only two morphological features combining the kaluga and the great sturgeon and separating them from other sturgeons, namely the shape of a mouth and the manner attaching of gill membranes to isthmus in adult specimens; whereas many morphological characters are different in these species. The relations of morphological similarity/distinction among different sturgeon species and polyphyletic origin of genus Huso revealed by both molecular and cytogenetic studies presume the restoration of initial taxonomic states for the great sturgeon and kaluga as members of the same genus Acipenser, namely A. huso and A. dauricus.     

Stress-protective and cross action of the extracellular reactivating factor of the microorganisms of the domains Bacteria, Archaea, and Eukaryota

Cross protection of members of the domains Bacteria, Archaea, and lower Eukaryota from stress factors due to the action of extracellular low-molecular metabolites with adaptogenic functions was shown. The adaptogen produced by Luteococcus japonicus subsp. casei and described previously as a reactivating factor (RF) was shown to protect the yeasts Saccharomyces cerevisiae, archaea Haloarcula marismorti, and the cells of higher eukaryotes (HeLa) against weak stressor impacts. Production of an archaeal extracellular metabolite with a weak adaptogenic effect of the producer cells and capable of a threefold increase in survival of heat-inactivated yeast cells was discovered. Our results confirm the similarity of the compensatory adaptive reactions in prokaryotes (bacteria and archaea) and eukaryotes.