The impact of fishery on the state of populations of the European whitefish Coregonus lavaretus in Lake Imandra

The impact of fishery on the state of populations of the European whitefish Coregonus lavaretus in Lake Imandra, the largest water body of the Kola Peninsula, is considered. The retrospective analysis of catches in the period of 1930 to 1998 indicated that the consequences of an uncontrolled fishery are comparable with the effects of intensive technogenic pollution. As a result of the intensive commercial load on the water body over many decades, the number of age groups decreases, the size-weight indices in fish change, an early maturation at sizes small for the species is observed, and the population structure becomes more simple. Against the background of the improving environmental quality, the numbers of fish under the effects of the uncontrolled amateur and poaching fisheries continue to decrease, which leads to the change of the nucleus of the fish proportion of the community and the change of dominant species.     

Solution structure of duplex DNA containing the mutagenic lesion 1,N(2)-etheno-2'-deoxyguanine

We have used high-resolution NMR spectroscopy and molecular dynamics simulations to determine the solution structure of DNA containing the genotoxic lesion 1, N (2)-etheno-2'-deoxyguanosine (epsilonG), paired to dC. The NMR data suggest the presence of a major, minimally perturbed structure at neutral pH. NOESY spectra indicate the presence of a right-handed helix with all nucleotides in anti, 2'-deoxyribose conformations within the C2'-endo/C1'-exo range and proper Watson-Crick base pair alignments outside the lesion site. The epsilonG residue remains deeply embedded inside the helix and stacks between the flanking base pairs. The lesion partner dC is extrahelical and is located in the minor groove of the duplex, where it is highly exposed to solvent. Upon acidification of the sample, a second conformation at the lesion site of the duplex emerges, with protonation of the lesion partner dC and possible formation of a Hoogsteen base pair. Restrained molecular dynamics simulations of the neutral-pH structure generated a set of three-dimensional models that show epsilonG inside the helix, where the lesion is stabilized by stacking interactions with flanking bases but without participating in hydrogen bonding. The lesion counterbase dC is displaced in the minor groove of the duplex where it can form a hydrogen bond with the sugar O4' atom of a residue 2 bp away.     

Experimental study of the properties of sublines of Rickettsia prowazekii vaccinal strain E

The instability of R. prowazekii strain E cultivated in chick embryos has been demonstrated. The complex of tests permitting determination of differences between various sublines of this strain in their immunogenic potency and residual virulence has been proposed.     

Posttranslational processing and differential glycosylation of Tractin, an Ig-superfamily member involved in regulation of axonal outgrowth

Tractin is a novel member of the Ig-superfamily which has a highly unusual structure. It contains six Ig domains, four FNIII-like domains, an acidic domain, 12 repeats of a novel proline- and glycine-rich motif with sequence similarity to collagen, a transmembrane domain, and an intracellular tail with an ankyrin and a PDZ domain binding motif. By generating domain-specific antibodies, we show that Tractin is proteolytically processed at two cleavage sites, one located in the third FNIII domain, and a second located just proximal to the transmembrane domain resulting in the formation of four fragments. The most NH(2)-terminal fragment which is glycosylated with the Lan3-2, Lan4-2, and Laz2-369 glycoepitopes is secreted, and we present evidence which supports a model in which the remaining fragments combine to form a secreted homodimer as well as a transmembrane heterodimer. The extracellular domain of the dimers is mostly made up of the collagen-like PG/YG-repeat domain but also contains 11/2 FNIII domain and the acidic domain. The collagen-like PG/YG-repeat domain could be selectively digested by collagenase and we show by yeast two-hybrid analysis that the intracellular domain of Tractin can interact with ankyrin. Thus, the transmembrane heterodimer of Tractin constitutes a novel protein domain configuration where sequence that has properties similar to that of extracellular matrix molecules is directly linked to the cytoskeleton through interactions with ankyrin.     

Topical x-ray anatomic parameters of the anterior foot

Roentgenometric parameters estimated by Russian radiologists and orthopedic surgeons fail to provide a complete and objective assessment of anterior foot deformity. Of practical interest is the larger number of indices the aggregate of which makes it possible not only to evaluate the severity of an abnormality, but also to choose a surgical treatment option that is optimal for the given foot. The authors' review of the most actual characteristics of a foot X-ray image does not substitute for more complex studies (computed tomography, magnetic resonance imaging), but it completely meets the requirements of current surgery of the anterior foot. Most parameters may be estimated in the dorsal plain (posterior) projection of the anterior foot under load.     

The effect of cooling rate, freeze-drying suspending fluid and culture age on the preservation of Campylobacter pylori

The effects of freezing rate, suspending fluid and age of culture on the ability of four strains of Campylobacter pylori to survive and recover from freeze-drying were examined. Freeze-drying by standard procedures generally resulted in an overall loss in viability of between 3 and 7 log units. The exact cause of poor recovery by C. pylori was not established but strain differences were detected, with NCTC 11637 (type strain) surviving better than NCTC 11638 and NCTC 11639. Recovery of the poorest growing strain (NE 26695) was notably more erratic. The largest loss in viability occurred at the primary drying stage. Losses resulting from freezing and secondary drying were less marked and the rate of freezing had only a marginal effect on recovery. Nineteen different freeze-drying suspending fluids were investigated. Overall the best recovery results were obtained with 5% inositol-broth (or horse serum) plus 25% glucose, at pH 7.0, in which loss of viability was typically about 4 log units. Other factors, such as age of culture and number of viable bacteria in the before-dry suspension, did not have a significant effect on survival. We conclude from these results that C. pylori can survive freeze-drying, albeit in small numbers, but the degree of recovery is apparently largely strain dependent.     

中国皿蛛科蜘蛛一新属和一新种记述(蛛形纲:蜘蛛目)

本文记述采自新疆的皿蛛科蜘蛛一新届——颚齿蛛属Maxillodens gen.nov.及其一新种——鞭状颚齿蛛M.flageuatus sp.nov。     

Specific antigen of granular cells of the human endometrium

Rabbits were immunized by homogenates of endometrium obtained from women during 10-12 weeks of gestation. A specific antiserum was obtained by absorption of the crude antiserum by blood cells and plasma proteins of men with different kinds of ABO and Rh antigens, till disappearance of positive reaction with men's serum protein in the Ouchterlony test. Such an adsorbed specific antiserum continued to react with the sera of pregnant women. Two antigens, numbers 1 and 2, respectively, were determined by the Ouchterlony test. Another group of rabbits was immunized by antigens detected in the precipitation test. A monospecific antidecidual antiserum (ADS 1092) was obtained against number 2 antigens. This antiserum revealed only one antigen in sera of women with gestation and did not react with sera of non-pregnant women. In the slides of endometrium of pregnant women of 10-12 weeks of gestation ADS 1092 had a strong positive reactive with the cytoplasm of one type of endometrium cells. The immunomorphological analysis by the non-direct Coons test and the PAP-test permits to identify cells with the positive reaction as granular cells. It is concluded that the granular cells may be a source of one of the serum antigens detected in women with gestation.     

The Effect of Tillage and Mesorelief on the Structure of Soil Microbial Cenoses

The investigation of soil microbial cenoses in cultivated catenas and in virgin soils at the foot of catenas showed that the structure of these microbiocenoses depends on the type of the vegetation cover, the characteristics of mesorelief, and the degree of soil tillage. The microbiocenoses were found to be dominated by the fungal mycelium. The proportion of bacteria and fungal spores was higher and the seasonal variations in the soil microbial communities were more distinct in the cultivated than in the virgin swamp and forest soils. The type of mesorelief was found to appreciably influence microbial populations in the top humus-rich horizons of the cultivated soils and not in the mineral soil horizons.