Trial of pertussis toxin activity in vitro on CHO cells

The activity of B. pertussis toxin has been tested in the continuous culture of CHO (Chinese hamster ovary) cells. The in vitro method of testing B. pertussis toxin is rapid, highly sensitive and specific. The unit of activity of B. pertussis toxin is higher than in mouse tests by several orders. The specificity of the action of B. pertussis toxin on CHO cells has been confirmed by the test of the neutralization of the toxicity effect with antiserum.     

Dipeptidyl aminopeptidase-IV in lymphocytes of patients with lymphoproliferative diseases

DAP-IV activity (Gly-Pro-MCA hydrolysis, pH 7.8) was found in lysates of peripheral blood lymphocytes of patients with T- and B-cell forms of malignant lymphoproliferative diseases. The highest DAP-IV activity was seen in the cells of patients with a rare variant of T-cell lymphocytic leukemia (T-CLL); these cells expressed simultaneously the antigens of T helpers and T suppressors (Th and Ts) (OKT4+ and OKT8+). The DAP-IV activity about ten times less was found in the pathological cells with a phenotype of mature Th (Sezary disease), as well as in the cells expressing antigens of both Ts and natural killers (a rare variant of T-CLL). The same activity was also found in Ts (T gamma-lymphocytosis). The data obtained show that the differences in DAP-IV expression are connected with the differentiation step rather than with the belonging to a particular subpopulation of T-cells. DAP-IV activity, which was somewhat lower than that of T-cells, was found in B-lymphocytes of patients with B-CLL, hair-cellular leukemia, and non-Hodgkin's lymphoma. No correlation of DAP-IV activity with the level of E-cellular differentiation was observed.     

Effect of bacterial toxins on the GTPase activity of transducin from bovine rod outer segments

The effects of choleragen- and pertussis toxin (PT)-induced ADP-ribosylation on the GTP-binding protein transducin (TD) from retinal rod outer segments (ROS) have been studied. It has been shown that both toxins cause inhibition of the TD GTPase activity. PT inhibited the GTPase by 30-40% in "native" ROS and by 70-80% in homogeneous TD. Choleragen, in contrast with PT, had no effect on the GTPase activity of homogeneous TD, but was as effective as PT in membrane preparations. The effects of both toxins on the GTPase activity of TD were found to be dependent on the chemical structure of the guanyl nucleotide present in the vehicle. The data obtained suggest that PT and choleragen differ in their specificity for the TD-guanyl nucleotide complex. The former can interact with free TD as well as with the TD-GDP complex, while the latter affects only the TD-GTP complex.     

Activity of some proteinases and glycosidases in human leukemic lymphoid cells at various stages of differentiation.

Activities of some glycosidases and proteinases in human leukemic lymphoid cells at various stages of differentiation have been compared. It was found that cells with different immunological phenotypes gave different enzymic spectra. Glycosidases and proteinases in lymphoid cell precursors had higher activity level than the enzymes in mature T- and B- cells. In cells of B- lineage, all activities were lower than in common precursor of lymphoid cells. In T-cells at the earlier stages of thymic differentiation, activities of all proteinases and most of glycosidases were higher than in common precursor cells whereas in mature T-helpers and T-suppressors the activities were markedly lower. Most of hydrolases in mature T-cells were twice more active than the enzymes in mature B-cells. The opposite-directional changes in activities of some hydrolases at the earlier stages of differentiation of lymphoid cells along B- or T- cells pathways are suggested.     

Furin as proprotein convertase and its role in normal and pathological biological processes

Furin belongs to intracellular serine Ca²⁺-dependent endopeptidases of the subtilisin family, also known as proprotein convertases (PC). Human furin is synthesized as a zymogen with a molecular weight of 104 kDа, which is then autocatalytically activated in two stages. This process occurs during zymogen migration from the endoplasmic reticulum to the Golgi apparatus, where a large part of furin is accumulated. The molecular weight of the active furin is 98 kDа. Furin is the enzyme with narrow substrate specificity: it hydrolyzes peptide bonds at the site of paired basic amino acids and is active in a wide range of pH (5.0–8.0). The main biological function of furin as PC consists in activation of functionally important protein precursors. This is accompanied by initiation of cascades of reactions, which lead to appearance of biologically active molecules involved in realization of specific biological functions both in normal and in some pathological processes. The list of furin substrates includes biologically important proteins such as enzymes, hormones, growth/differentiation, receptors, adhesion proteins, plasma proteins. Furin plays an important role in the development of such processes as proliferation, invasion, cell migration, survival, maintenance of homeostasis, embryogenesis, as well as the development of a number of pathologies, including cardiovascular, cancer, and neurodegenerative diseases. Furin and furin-like proprotein convertases are key factors in the realization of the regulatory functions of proteolytic enzymes; the latter is currently considered as the most important function (compared with well recognized protease function in degradation of proteins).     

Hibernation in the Eversman hamster (Allocricetulus eversmanni Brandt, 1859) from the Saratov Trans-Volga region

The hibernation of the Eversman hamster is proven for the first time. The body temperature measured with a thermoaccumulator implanted into the abdominal cavity dropped down to +5°C several times during the winter. This species differs from other hibernating mammals in the peculiarities of its seasonal fluctuation of steroid hormones (cortisol, progesterone, estradiol, and testosterone) and in the absence of fat deposits before hibernation.     

Allele Diversity of the Major Histocompatibility Complex in the Common Hamster (Cricetus cricetus) in Urban and Rural Populations

Biology Bulletin - Based on the results of targeted sequencing on the Illumina platform we compared the allelic diversity of exon 2 of the DRB gene in urban (city of Simferopol) and rural...     

Deamination of indolalkylamines in hyperthermia

The experiments on dogs subjected to the outward overheating allow concluding that the quantities of deaminated serotonin in mitochondrial fractions of the brain stem, heart muscles and liver increase twice as compared with the normal levels. Particularly, in the liver the value of Km of this process is equal to 1.6 x 10(-3) M, while without the overheating it is equal to 3.6 x 10(-3) M. Overheating makes the process of tryptamine deamination in mitochondrial fractions of the heart and liver more intensive. However, overheating causes a higher increase of the monoaminooxidase activity with respect to serotonin than with respect to other substrates.     

Isolation of various structural elements of gram-negative bacteria of the Bordetella genus and a study of their properties. II. Isolation of the cytoplasmic membrane fraction from the protoplasts of B. pertussis and a study of their chemical and enzymatic properties]

A possibility of obtaining a fraction of cytoplasmic membranes maximally purified of the cell wall material was for the first time shown on a model of Gram negative bacteria (B. pertussis). The results of electron microscopy, chemical analysis for the presence of the cell wall material--hexosamines, and of the activity of the respiratory chain enzymes served as control.