Effect of trophoblast-specific beta 1-glycoprotein on the ratio of cellular forms in a mast cell population

The influence of trophoblast-specific beta 1-glycoprotein (TSG) on the degranulation of mast cells and their saturation with heparin was studied. Introduction of the TSG into the population of mast cells of the rat peritoneal fluid practically does not change their degranulation, but lowers the degree of their saturation with heparin. An antibiotic alone increases the saturation of the cells with heparin. The serum of an allergic animal markedly stimulates the degranulation and lowers the degree of saturation of the mast cells with heparin. In an experimental model (antibiotic--the serum of the allergic mast cells) the mast cells transform into very clear (heparin-free) cells and the degree of saturation is at minimum. The TSG introduction into this system stabilizes the population of mast cells and markedly increases the degree of their saturation with heparin. Although the degranulation is rather intensive, it is less expressed, than in the experimental model. This suggests the presence of TSG receptors on the mast cells (targets of allergic reactions). The possibility to use TSG preparations in the therapy of allergic diseases is discussed.     

Hypoxia during mammalian preimplantation development: Extreme circumstance vs. typical environment

The given paper summarizes the data on the early mammalian embryo development in culture media containing low oxygen concentration. Experimental results on in vitro modeling the hypoxia for preimplantation development are reviewed. Hypoxic conditions were shown to be available in the female reproductive tract of different mammalian species. The estimation of the embryo developing in vitro exhibits that lower oxygen level in culture media improves embryonic quality.     

Activation of specific membrane mechanisms in the myocardium cells on early stages of ischemia

Electron probe microanalysis was employed to determine the elemental concentration (K,Na,Cl) in a myocyte on cryosections of the papillary muscle of the isolated rat (Wistar) heart. Protocols of global ischemia and ischemic conditions under glucose-free anoxic perfusion were applied. It was shown that global ischemia induces potassium deficiency (94 +/- 2 mM) in the myocyte and an increase in the level of sodium (72 +/- 4 mM) and chlorine (42 +/- 1 mM) in the cytoplasm compared with intact cell (122 +/- 2; 36 +/- 1; 24 +/- 1 mM). Glucose-free anoxic perfusion leads to a smooth fall of potassium concentration in the cell up to 54 +/- 2 mM with the retention of intracellular sodium (40 +/- 1 mM) and chlorine (26 +/- 1 mM) level. The present finding suggest that, in early ischemia, specific membrane mechanisms of ion transport are activated. Among these are KNa channel, Hi(+)-Nao+ exchange, KATP channel, lactate transport from the cell, associated either with potassium efflux to the extracellular space or chlorine influx into the myocyte. It is assumed that Na/K-ATPase is also activated under ischemic conditions.     

Immunochemical analysis of lectin receptors in the structure of trophoblastic beta 1-glycoprotein and pregnancy-associated alpha 2-glycoprotein

Trophoblastic beta-glycoprotein (TBG), pregnancy-associated alpha 2-glycoprotein (AGP) and alpha-fetoprotein (AFP) bind to concanavalin A, phytohemagglutinin P and pea lectin. Lentil lectin interacts with TBG only, whereas peanut lectin and castor bean lectin are characterized by affinity to AGP. Hence, TBG, AGP and AFP contain the following carbohydrate components: alpha-D-mannose, alpha-D-glucose, N-acetyl-D-glucosamine and N-acetyl-D-galactosamine. In addition, AGP contains beta-D-galactose.     

Laser-scanning microscopy as applied to mouse early embryos: Cytometry and analysis of cell morphology

This paper updates our knowledge on quantitative laser scanning microscopy and summarizes the capabilities of this method as applied to cytometry and analysis of cell structure of the mouse early embryo and the oocyte. This method requires a stack of optical sections obtained as Z-series with subsequent 3D reconstruction. This approach was used for visualization of the 3D cell model, measurement of the cell volume and surface area, as well as a study of the cell interior via optical sections. To maintain the dimensional characteristics of embryos or oocytes the method of sample preparation involved the following consequent steps: rapid cryofixation, low-temperature dehydration, infiltration by optically transparent mounting media, and laser-scanning microscopy. This strategy enables volume measurement, even in the case of a single cell within the multicellular system of the mouse early embryo.     

Cobalt-dependent transcription of the nitrile hydratase gene in Rhodococcus rhodochrous M8

Abstract The effects of cobalt ions on the activities of Rhodococcus rhodochrous M8 enzymes for nitrile utilization, nitrile hydratase and amidase, were investigated. In contrast to amidase, synthesis of nitrile hydratase and its activity required cobalt ions in the growth medium. Northern blot analysis showed that in the presence of cobalt ions, the level of mRNA for nitrile hydratase genes was several times higher than that under cobalt-limited conditions. It was assumed that the low nitrile hydratase activity in cells grown in the absence of cobalt ions is connected either with the weak expression of nitrile hydratase genes or with the rapid degradation of nitrile hydratase mRNA.     

Phenotypic variability in <Emphasis Type="Italic">Azospirillum brasilense</Emphasis> strains Sp7 and Sp245: Association with dormancy and characteristics of the variants

The state of metabolic dormancy in diazotrophic bacteria Azospirillum brasilense Sp7 (non-endophytic strain) and Sp245 (endophytic strain) was found to be associated with phenotypic variability. The latter manifested itself in the extension of the spectrum of A. brasilense phenotypic variants resulting from plating of cyst-like resting cells (CRC) on solid media and was more pronounced in strain Sp7. The major colony’s morphological variants of strain Sp7 were (1) the dominant S type; (2) the highly pigmented Pg type; (3) the R type; (4) the Sm type, forming small colonies; and (5) the Sg type, forming segmented colonies. In addition to their colony morphology, the variants differed in the phenotype stability during transfers on the standard solid medium and in their motility in semisolid agar. The occurrence frequency of the phenotypic variants depended on the conditions and duration of incubation (storage) of the CRC of strain Sp7, as well as on heat treatment (at 55 and 60°C for 10 min) of the cells prior to inoculation. The maximum frequency of S → Pg transitions (up to 74%) was observed during the germination of CRC stored in a spent culture medium at −20°C for 4 months; the maximum frequency (up to 100%) of S → Sm transitions was observed after inoculation of the CRC subjected to heat treatment. The Pg variants were the most stable, whereas other types reverted rapidly to the S or Pg variant. The S variant grown in semisolid agar exhibited the mixed type of motility (Swa⁺Gri⁺, swarming and migration in the form of microcolonies); the Pg and Sg variants showed the Swa⁺Gri⁻ (swarming) phenotype and the Sm variant was nonmotile (Swa⁻Gri⁻ phenotype). The spectrum of phenotypic variants of the endophytic strain Sp245 was narrower than that of strain Sp7 and was represented by S, Sm, and M (mucoid) variants that differed in the patterns of cell motility: the dominant S type displayed the swarming pattern (Swa⁺Gri⁻), the mucoid M type showed the mixed type (Swa⁺Gri⁺) of motility, and the Sm variant was nonmotile. The differences between the nonendophytic strain Sp7 and the endophytic strain Sp245 in their capacity for phenotypic dissociation and cell motility in semisolid media may reflect their ability to adapt to changing ambient conditions and specificity of plant-microbial interactions.     

Dynamics of cell volume in early mouse embryos subjected to hypotonic shock

Osmotic adaptation in a mouse embryo blastomere has been studied by direct measurement of the cell volume using microtomography (laser scanning microscopy followed by quantitative 3D reconstruction). Embryo cells subjected to hypotonic shock first swelled but then returned to the initial size. At the beginning of osmotic stress, the swelling obeyed the van’t Hoff equation with a water permeability coefficient of 0.4 μm min⁻¹ atm⁻¹. The regulatory volume decrease was not abolished by Na⁺/K⁺-ATPase inhibition.     

Does an electroneutral K<Superscript>+</Superscript>/Cl<Superscript>−</Superscript> antiport occur in cardiomyocyte during acute ischemia?

Electron probe microanalysis was applied to determine cytoplasmic elemental (K, Na, Cl) concentrations in cardiac cells of the rat (Wistar). Potassium, sodium and chlorine contents were measured in papillary muscle myocytes of the rat heart perfused by the Langendorff procedure. Ischemic depletion was created by perfusion with deeply deoxygenated Tyrode’s solution in the absence of glucose. It was found that the initial phase of acute ischemia is characterized by the potassium deficiency and the accumulation of sodium and chlorine in cardiac myocytes. It should be noted that changes in the total charge of the main intracellular cations (K⁺, Na⁺) do not compensate for the increased chlorine concentration. This result can be accounted for by the appearance of ionic (K⁺ and Cl⁻) transport coupled with the removal of lactate anions produced in cardiomyocytes during anaerobic glycolysis.     

Immunochemical analysis of the interaction of the fertility alpha 2-microglobulin with steroid sex hormones

The interaction between the fertility alpha 2-microglobulin and steroid sex hormones (estrone, estriol, estradiol, progesterone, testosterone) was studied by the use of cross immunoelectrophoresis with intermediate gels. alpha 2-microglobulin was shown to bind to the above hormones, its affinity to testosterone being the highest. The ability of alpha 2-microglobulin to bind to steroid hormones can be used for its isolation by affinity chromatography with immobilized steroid hormones.