Evaluation of cell proliferation kinetics by the differential staining of the sister chromatids at 2 points of cell fixation

Lymphocyte proliferation in blood cultures from 23 normal individuals was studied. A simple method of evaluation of cell proliferative kinetics with sister chromatid differential staining using two different points of cell harvesting was suggested. It was shown that different composition of tissue culture medium plays a significant role during the cell exit from G0 stage, the mean doubling generation time of cellular population remaining constant.     

Effect of helium and argon on the oxygen uptake by lymphocytes

The effect of inert helium and argon gases on the tissue respiration has been studied on lymphocyte suspensions of white rats. It is shown that normoxic helium-oxygen mixture induces almost a two-fold increase of the O2 uptake by lymphocytes as compared with the control (air). No deviations in the value of the studied parameter are revealed in case of replacement of nitrogen from air by argon. Significance of the membrane structure in realization of effects of inert gases is under discussion.     

A complex medico-genetic study of West Siberian populations. I. Formulation of a problem. Goals and objectives of the study. Population genetic characteristics of Northern Khanty

Purposes and tasks of the complex medical and genetic study of West-Siberian inhabitants were formulated. Demographic parameters for the North Khanty inhabitants, such as size, dynamics of the tertiary sex ratio, marriage structure and migration processes were presented. Mating and intrapopulation migration patterns are determined by spatial subdivision, because of the vast territory and the traditional way of life, and by isolation by distance. Index of the isolocal endogamy equals to 0.364. The portion of mixed marriages is 22.7% and that of the gametic contribution of immigrants - 7.3%. Inbreeding coefficient by isonymy is 0.00097. Effective population size of the five subpopulations studied as a whole is 25% of their total number.     

Determination of inhibition sites during hydrolysis of polydeoxyribonucleotides by exonucleases III from Bacillus amyloliquefaciens and Escherichia coli

The influence of the primary structure of polydeoxyribonucleotides on the rate of hydrolysis with exonuclease III from Bacillus amyloliquefaciens and Escherichia coli was investigated. The substrates used were synthetic oligodeoxyribonucleotides and pBR 322 DNA fragments labeled with 32P at the 5'-termini of one of the chains. According to the data from polyacrylamide gel electrophoresis performed under denaturing conditions, the hydrolysis of these substrates by unsaturating concentrations of B. amyloliquefaciens and E. coli exonuclease III proceeds with several reproducible "stops". The decrease of the reaction rate was shown to take place just before the pyrimidine blocks in the digested DNA chain.     

Anonymous nuclear DNA markers in the American oyster and their implications for the heterozygote deficiency phenomenon in marine bivalves

A puzzling population-genetic phenomenon widely reported in allozyme surveys of marine bivalves is the occurrence of heterozygote deficits relative to Hardy-Weinberg expectations. Possible explanations for this pattern are categorized with respect to whether the effects should be confined to protein-level assays or are genomically pervasive and expected to be registered in both protein- and DNA-level assays. Anonymous nuclear DNA markers from the American oyster were employed to reexamine the phenomenon. In assays based on the polymerase chain reaction (PCR), two DNA-level processes were encountered that can lead to artifactual genotypic scorings: (a) differential amplification of alleles at a target locus and (b) amplification from multiple paralogous loci. We describe symptoms of these complications and prescribe methods that should generally help to ameliorate them. When artifactual scorings at two anonymous DNA loci in the American oyster were corrected, Hardy-Weinberg deviations registered in preliminary population assays decreased to nonsignificant values. Implications of these findings for the heterozygote-deficit phenomenon in marine bivalves, and for the general development and use of PCR-based assays, are discussed.      

Basolateral plasma membrane localization of ouabain-sensitive sodium transport sites in the secretory epithelium of the avian salt gland

The distribution of Na+ pump sites (Na+-K+-ATPase) in the secretory epithelium of the avian salt gland was demonstrated by freeze-dry autoradiographic analysis of [(3)H] ouabain binding sites. Kinetic studies indicated that near saturation of tissue binding sites occurred when slices of salt glands from salt-stressed ducks were exposed to 2.2 μM ouabain (containing 5 μCi/ml [(3)H]ouabain) for 90 min. Washing with label-free Ringer's solution for 90 min extracted only 10% of the inhibitor, an amount which corresponded to ouabain present in the tissue spaces labeled by [(14)C]insulin. Increasing the KCl concentration of the incubation medium reduced the rate of ouabain binding but not the maximal amount bound. In contrast to the low level of ouabain binding to salt glands of ducks maintained on a freshwater regimen, exposure to a salt water diet led to a more than threefold increase in binding within 9-11 days. This increase paralleled the similar increment in Na+-K+-ATPase activity described previously. [(3)H]ouabain binding sites were localized autoradiographically to the folded basolateral plasma membrane of the principal secretory cells. The luminal surfaces of these cells were unlabeled. Mitotically active peripheral cells were also unlabeled. The cell-specific pattern of [(3)H]ouabain binding to principal secretory cells and the membrane-specific localization of binding sites to the nonluminal surfaces of these cells were identical to the distribution of Na+-K+-ATPase as reflected by the cytochemical localization of ouabain-sensitive and K+-dependent nitrophenyl phosphatase activity. The relationship between the nonluminal localization of Na+-K+-ATPase and the possible role of the enzyme n NaCl secretion is considered in the light of physiological data on electrolyte transport in salt glands and other secretory epithelia.     

Oxygen binding of myoglobins of diving animals]

When studying oxygen binding by myoglobins of diving animals it is shown that half-saturation of myoglobins obtained from the muscles of animals who can stop the external respiration for a long period of time occurs at oxygen strength of 0.62-0.67 mm Hg. Such indices of oxygenation of respiratory hemoprotein of muscles are characteristic of most mammals. Temperature being decreased from 37 to 15 degrees C, myoglobin affinity to oxygen considerably increases.     

Mechanism of ethonium effect on membrane preparations of brain Na+, K+-ATPase

The effect of ethonium, a local anesthetic, on the membrane preparations of brain N+, K+-ATPase was studied by fluorescent, radioisotopic, electron-microscopic and electrophysiological methods. Ethonium is established to affect the formation of an intermediate phosphorylated product and has no pronounced destructive effect on the membrane. It changes the fluorescence intensity of 2-toluidinonaphthalen-6-sulphonate (TNS), astrafloxin (AF) and fluorene probes in a suspension of the Na+, K+-ATPase preparations, which evidences for ethonium-induced changes in the structure of membrane fragments.