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Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.
The aim of the present paper was to find out by in vitro chromosomal aberration test using human lymphocytes whether cysteine has anticlastogenic properties towards a well-known mutagen - mechlorethamine. The lymphocytes tested were obtained from three healthy donors. Two doses of cysteine (1.0 and 2.0 μg/ml) and three doses of mechlorethamine (0.1,0.2 and 0.3 μg m⁻¹) were tested. It was found that cysteine had anticlastogenic properties and that it reduced the number of metaphases with chromosomal aberrations induced by mechlorethamine.
The influence of 3-methylcholanthrene to zebra mussel (Dreissena polymorpha) larvae was studied. The artificial spawning of zebra mussels was used for obtaining larvae. Two different concentrations of 3-methylcholanthrene were used. The chromosome analysis showed a significant increase in chromosome aberrations (CA) at the higher concentration of the compound. The resistance of zebra mussel larvae to the lower concentration of 3-methylcholanthrene indicated that zebra mussel larvae are probably not sensitive enough for the study of genotoxicity of the compounds from the PAH group.
Pre- and postnatal diagnosis of chromosomal aberrations is generally based on conventional cytogenetic analysis. In this paper, we have devised a quantitative polymerase chain reaction (Q-PCR) method to determine gene dose effects and applied it in cases of regular trisomy 21 as a model. The method is based on quantitative assessment of PCR products after using primers amplifying DNA fragments located in the pericentromeric, heterochromatic, euchromatic and telomeric regions of chromosome 21. A gene dose effect on the amount of PCR product in cases of trisomy 21 was confirmed. Moreover, a correlation between the amount of the PCR product of the examined sequences and their location in the chromosome was observed. The obtained results suggest that the Q-PCR technique can be applied in the diagnosis of aneuploidies.
Chromosome morphology was studied in lily genotypes L. candidum, L. x formolongi, L. henryi and L. pumilum, and cultivars ‘Alma Ata,’ ‘Expression,’ ‘Marco Polo,’ ‘Muscadet’ and ‘Star Gazer’ belonging to the horticultural group Oriental hybrids. All genotypes tested represented 2n = 2x = 24 chromosomes. Chromosomal markers were established after Feulgen and silver staining, from analysis of the chromosome length and position of the primary and secondary constrictions. For each chromosome the arm index was calculated. Based on these data, idiograms were drawn. For the genotypes analyzed the markers were the secondary constrictions, as confirmed by silver staining. Chromosome length can be used as a marker in only a few cases. From 4 to 10 chromosomes could be identified using secondary constrictions as markers, depending on the genotype. Markers are proposed for each possible species x cultivar and cultivar x species combination.
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