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24-Epibrassinolide at Subnanomolar Concentrations Modulates Growth of Mouse Hybridoma Cells
Franěk, František ; Kohout, Ladislav ; Eckschlager, T.
Brassinolides are known to stimulate plant growth and to posses antistresiTactivities in plants. This work was aimed at exploring possible beneficial effects of 24-epibrassinolide on cultured mammalian cells. A mouse hybridoma, i.e. a hybrid ymphocyte cell line, was cultured either in standard serum-free medium, or in diluted medium in which the cell grew inder nutritional stress. Steady-state parameters of semicon-finuous cultures conducted at 24-epibrassinolide concentra-ions from 10~16 M to 1CT9 M were evaluated. Typical effects of he agent that were observed both in standard and in diluted i [media were suppression of intracellular antibody level, increa- / ,ed value of mitochondrial membrane potential, higher frac- / ion of cells in the G(/Gl phase and lower fraction of cells in / he S phase. Alleviation of nutritional stress was observed in j (cultures conducted in diluted media. Viable cell density was j ignificantly higher at 24-epibrassinolide concentrations 10~13[ knd 10~12 M. Results of this exploratory study show that thej plant hormone 24-epibrassinolide may induce alterations of he cell division mechanism of the energetic metabolism, and of secreted protein synthesis in a mammalian cell line.
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Recent recovery of acidified lakes in the Bohemian Forest
Vrba, Jaroslav ; Fott, J. ; Kopáček, Jiří ; Kohout, L.
In some of the eight glacial lakes in the Bohemian Forest we have observed first signs of zooplankton recovery from acidity. The recovery has followed a drop in atmospheric sulphur and nitrogen deposition and consequent reversal in water chemistry of the lakes during the last decade. At present, stable populations of Ceriodaphnia quadrangula have returned to Lake Černé and Prášilské, and two circumneutral rotifers have recently occurred in the lakes with positive alkalinity: Laka, Großer and Kleiner Arbersee. Moreover, in the mesotrophic, strongly acidified Lake Plešné, we documented increase in both phytoplankton and planktonic rotifers during the 1990s. A statistical comparison of seasonal data showed a significant increase in pH, a significant drop in total reactive aluminium, a significant increase in chlorophyll a concentration as well as in summer abundance of planktonic rotifers.
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Vliv okolního prostředí na semena
Bláha, L. ; Kohout, Ladislav ; Hnilička, F. ; Gottwaldová, P. ; Jankovská, P.
Stress abiotic factors affect chemical composition of seeds, yielding traits, seed traits and traits of sprouting plants-especially root traits: length, surface, weight, nutrient uptake, number of root tips, number of root hairs, number of lateral roots and density
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