Maria Joanna Olszewska

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Nuclear DNA and AgNOR-area quantity have been measured cytophotometrically, the number of silver grains afterin situ 3H rDNA/DNA hybridization has been counted, and the level of rDNA methylation has been estimated in root meristems, differentiated root zones, hypocotyls, cotyledons, and leaves of 7-day-old seedlings ofLupinus luteus. DNA content increases(More)
Dimensions,dry mass content, binding of [3H]actinomycin D ([3H]AMD), and [3H]uridine incorporation in the nuclei and nucleoli as well as their ultrastructure during growth and differentiation of the root cortex cells of Haemanthus katharinae were compared. The dry mass of the nuclei did not change, the condensed chromatin content was slightly augmented, and(More)
After cycloheximide treatment (1 h, 2.5 micrograms/ml) protein synthesis was decreased by 70% and was partially restored after 7 h of postincubation (still 20% decrease). In partially synchronized root meristems of Vicia faba L. treated with cycloheximide at middle G2, a strong decrease of the mitotic index was observed. Exposure to the drug at late G2 did(More)
Activities of DNA polymerases and RNA polymerases were studied by autoradiographic methods in growing and differentiating root cortex cells ofZea mays — a species in which endomitosis occurs — andTulipa kaufmanniana — in which this process does not occur. InTulipa kaufmanniana, the highest activity of DNA polymerase appears in the nuclei of meristematic(More)
Cold treatment (10‡C) of root meristem during a period longer than duration of the cell cycle in 20‡C causes a blocking of most cells in G1. One of the causes of cell cycle blockade is the decrease of rRNA synthesis and inhibition of rRNA transport into cytoplasm. Transfer of seedlings to 20‡C results in increase of rRNA synthesis and its transport to(More)
The occurrence and level of nuclear DNA endoreplication (Feulgen cytophotometry) were compared in mesophyll and bundle sheath cells during leaf differentiation ofMuscari comosum (2 C DNA-12.7 pg),Allium cepa (2C DNA-33.5 pg),Allium porrum (2 C DNA -65.3 pg), fromLiliaceae family, andAmaryllis belladonna (2 C DNA-30.1 pg) andClivia miniata (2C DNA-46.9 pg)(More)
The effects of beta-mercaptoethanol on the mitotic index, phase index, condensation of chromatin in late G2 phase and in metaphase chromosomes, and on the content of protein -SH groups in successive developmental stages of antheridial filaments of Chara vulgaris L. were investigated. It has been shown earlier that as the development of antheridial filaments(More)
Experimental model consisted in blocking cells in G1 phase by cold treatment (12 h, 10 degrees C); following 3 h of postincubation at 20 degrees C, cells initiated S phase. In the present studies it has been shown that 2 h postincubation at 20 degrees C of cold-treated young seedlings of Helianthus annuus L. results in transformation of inactive(More)
The incubation of root meristem of Vicia faba L. with 5-azacytidine for 72 h (5 cell cycles) resulted in shorter DNA fragments after digestion with a restriction enzyme Sau3A. Under the same condition in situ digestion of metaphase chromosomes with Sau3A revealed a stronger banding (C-banding-like) pattern in 5-azacytidine-treated chromosomes than in the(More)
The experimental conditions for DNAase I digestion in situ for plant nuclei have been presented. Cytophotometric measurements of DNA loss performed on Feulgen-stained nuclei of three species differing in 2C DNA, heterochromatin and condensed euchromatin contents have shown that the lower 2C DNA amount the higher is DNase I sensitivity. Heterochromatin and(More)