Mechanism of activation of Na,K-ATPase in nerve fibers during rhythmic excitation

The activation mechanism of Na,K-ATPase in nerve fibres after rhythmic excitation was studied. 3H-ouabain binding to a nerve was found to depend on the frequency of rhythmic excitation. The maximum of 3H-ouabain binding to a nerve crab was at 10 imp/sec. Rhythmic excitation was found not to change Na,K-ATPase affinity to ouabain, but appeared to increase the concentration of ouabain-sensitive sites in the nerve membrane. Transformation of inactive forms of the enzyme into active ones was supposed to be a possible cause of greater 3H-ouabain binding to the nerve during rhythmic exitation.     

Cardiovascular peculiarities in hypertensive rats (Hsiah strain) after antihypertensive drug intervention during juvenile period of life

Treatment with different types of antihypertensive drugs during second month age has not prevented development of arterial hypertension and myocardial hypertrophy in the adult rats with inherited stress-induced arterial hypertension. At 6 months of age, the 11% attenuation of basal blood pressure has beet achieved only in the rats treated with angiotensin-converting enzyme inhibitor enalapril. Nevertheless, they expressed the most pronounced left ventricular hypertrophy. The unfavorable tissue and ultrastructural abnormalities were revealed in the myocardium of the rats which received the alpha1-adrenoceptor blocker terazosin. The delayed effects of losartan (angionetsin II receptor antagonist) and corinfar (calcium channel antagonist) on the myocardial structure were inessential.     

Immobilization of Rhodococcus ruber strain gt1, possessing nitrile hydratase activity, on carbon sorbents

Rhodococcus ruber strain gtl, possessing nitrile hydratase activity, was immobilized by adsorption on carbon supports differing in structure and porosity. The adsorption capacity of the supports towards cells, the substrate of the nitrile hydratase reaction (acrylonitrile), and the product (acrylamide) was studied. Also, the effect of immobilization and nitrile hydratase activity of bacteria was investigated, and the operational stability of the immobilized biocatalyst was determined. It was shown that crushed and granulated active coals were more appropriate for immobilization than fibrous carbon adsorbents.     

Analysis of clonal type-specific antibody reactions in Toxoplasma gondii seropositive humans from Germany by peptide-microarray

Background

Different clonal types of Toxoplasma gondii are thought to be associated with distinct clinical manifestations of infections. Serotyping is a novel technique which may allow to determine the clonal type of T. gondii humans are infected with and to extend typing studies to larger populations which include infected but non-diseased individuals.

Methodology

A peptide-microarray test for T. gondii serotyping was established with 54 previously published synthetic peptides, which mimic clonal type-specific epitopes. The test was applied to human sera (n = 174) collected from individuals with an acute T. gondii infection (n = 21), a latent T. gondii infection (n = 53) and from T. gondii-seropositive forest workers (n = 100).

Findings

The majority (n = 124; 71%) of all T. gondii seropositive human sera showed reactions against synthetic peptides with sequences specific for clonal type II (type II peptides). Type I and type III peptides were recognized by 42% (n = 73) or 16% (n = 28) of the human sera, respectively, while type II–III, type I–III or type I–II peptides were recognized by 49% (n = 85), 36% (n = 62) or 14% (n = 25) of the sera, respectively. Highest reaction intensities were observed with synthetic peptides mimicking type II-specific epitopes. A proportion of the sera (n = 22; 13%) showed no reaction with type-specific peptides. Individuals with acute toxoplasmosis reacted with a statistically significantly higher number of peptides as compared to individuals with latent T. gondii infection or seropositive forest workers.

Conclusions

Type II-specific reactions were overrepresented and higher in intensity in the study population, which was in accord with genotyping studies on T. gondii oocysts previously conducted in the same area. There were also individuals with type I- or type III-specific reactions. Well-characterized reference sera and further specific peptide markers are needed to establish and to perform future serotyping approaches with higher resolution.     

Multifunctional morphology of the chick chorioallantoic membrane

The chicken chorioallantoic membrane is assessed between days 7 and 20 of incubation using light and electron microscopy with morphometric analysis. The completion of its formation by the middle of embryogenesis is observed, after that a rapid increase in the embryo body mass continues. The bloodstream combines chorionic epithelium, mesoderm, and allantoic epithelium into the single multifunctional organ. The ordered antiparallel arrangement of afferent and efferent vessels within the mesoderm as well as their specialized endothelium assist in partial blood fluid filtration into the interstitium. The unique structure of the capillary network within and over the chorionic epithelium that provide for the effective gas exchange is depicted. It is revealed that the ultrastuctural specialization of the chorionic epithelial cells through which an active calcium transport from the eggshell takes place. The ultrastructure peculiarities of the allantoic epithelium concerning the water-salt balance maintaining in the growing embryo, are discussed.     

Effects of DNA quality on the measurement of telomere length

Molecular Biology - Existing evidence on the association of telomere length with life expectancy and the risk of various age related diseases is discordant. This inconsistency in the data may be...     

Monitoring the seasonal dynamics of ecologically tolerable levels for water regime, temperature, and pH in water objects of the Lower Don River

The feasibility of ecological standardization of physicochemical factors that do not refer to concentrations of polluting substances (water regime, water temperature, and pH) is confirmed. The opportunity of standardization is provided with the approach developed by the authors, which is based on joint analysis of the data of biological and physicochemical monitoring. Additional opportunities provided by the method used for the analysis are connected with calculating the admissible influence values that vary in time. The seasonal dynamics of the obtained ecologically tolerable levels (ETL) for factors disturbing the well being of biological indicators is investigated. The water sample points are analyzed concerning their ecological well being or ill being depending on observance or nonobservance of ETL values.