The role of glutathione in natural and modified radioresistance of yeast cells

A study was made of the dependence of different natural and modified radioresistance upon glutathione content of yeast cells (Saccharomyces cerevisiae and Pichia guilliermondii). It was shown that glutathione was only involved in the formation of natural radioresistance in Saccharomyces cerevisiae cells. It was also shown that the increase in the radioresistance of yeast cells under the effect of 2-amino-2-thiazoline was accompanied by the increase in the level of total glutathione in them.     

Mechanisms in the regulation of the level of lipid radiosensitizing agents in yeast cells with different types of radioresistance

Factors controlling the lipid sensitizers level: the composition of fatty lipid acids, their antioxidative activity, the enzyme systems reactivity (superoxide dismutase, catalase, glutatione peroxidase and glutatione reductase) have been studied in yeast cells with different radioresistance. In six lines of yeast cells the leading role of superoxide dismutase--one of the regulators of lipid peroxidation have been demonstrated in cells native radioresistance formation.     

Nitroxyl compounds in bacteria: Search for functions

A method was developed for incorporation of two deuterium atoms into the reactive group of a new type of nitroxyl compounds from Micrococcus luteus (a lysodektose which can be transformed into a long-living free radical). This compound was found to persist in the cells treated with gentamycin and chloramphenicol, while treatment with gramicidin C, ampicillin, benzyl viologen, furadonin, and mercury chloride resulted in a drastic decrease of its intracellular content. Cultivation of M. luteus in a medium with EDTA resulted in accumulation of much higher amounts of lysodektose (up to 300%), and this phenomenon is interpreted as an indication of the possible siderophore function of the compound. Since the M. luteus genome was recently sequenced, this may help to understand the fate and role of lysodektose in bacterial metabolism.     

Osteogenic differentiation of mouse bone marrow stromal cells on fibroin microcarriers

We investigated the proliferation and osteogenic differentiation of mesenchymal stem cells cultured on fibroin microcarriers. Effective cell proliferation on the surface of the microcarriers, determined by the large surface area, and the contribution of microcarrier mineralization to the stimulation of the osteogenic differentiation of mesenchymal stem cells was revealed.     

Effect of 2-amino-2-thiazoline on the level of lipid peroxidation products in different yeast species

The influence of 2-amino-2-thiazoline on lipid peroxidation in yeasts Saccharomyces cerevisiae and Pichia guilliermondii has been studied in vivo and in vitro. In the case the radioresistance of diploid yeasts-saccharomycetes is changed the radioprotector can produce a direct effect on lipid peroxidation. Different radioprotective efficiency of the preparation with regard to different strains of one and the same yeast culture is explained by its different influence on the content of endogenous radioprotective factors exerting a control over the accretion of lipid peroxidation products. The observed differences in the lag-periods of peroxidation in Saccharomyces cerevisiae and Pichia guilliermondii correspond to the level of their natural antioxidant activity of lipids.     

Calcium-transporting system of erythrocytes in psoriasis

The activity of Ca-ATPase and permeability of erythrocyte membrane for calcium in patients with psoriasis were studied with the aim to reveal disturbances in the calcium membrane transport under psoriasis. In the presence of endogenic activators the mean values of the maximal Ca-ATPase activity of erythrocyte membranes in patients with psoriasis and in healthy people have no essential differences and make up 264 +/- 12 and 244 +/- 10 mumol P/1 cells per 1 min, respectively. The rate of 45Ca accumulation in erythrocytes under inhibition of Ca-ATPase in patients suffering from psoriasis is by 64% higher than in healthy people. The data obtained along with the previously revealed changes in the calcium metabolism in patients with psoriasis make it possible to suppose the presence of the system disturbance of the calcium membrane transport, in particular an increase in the plasma membrane permeability for cells of different types. Such a disturbance may distort a regulatory (messenger) function of calcium ions in the processes of proliferation, differentiation, functional activity and death of different cell types.     

A new endemic species of Helichrysum Gaertn. (Asteraceae-Inuleae) from south Anatolia

A new species of Helichrysum Gaertn., H. orbicularifolium Sümbül, R. S. Göktürk & O. D. Düşen sp. nov. , is described and illustrated. The species is restricted to the south Anatolia Province, Antalya, Turkey, growing in humid calcareous rock crevices and on limestone cliffs. The species is compared with the closely related H. chasmolycicum . © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 251–254.