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1.
Core histones are subjected to various post-translational modifications, and one of them, most intensively studied in plants, is the methylation of histone H3. In the majority of analyzed plant species, dimethylation of H3 at lysine 9 (H3K9me2) is detected in heterochromatin domains, whereas methylation of H3 at lysine 4 (H3K4me2) is detected in euchromatin domains. The distribution of H3K9me2 in the interphase nucleus seems to be correlated with genome size, chromatin organization, but also with tissue specificity. In this paper, we present the analysis of the pattern and level of histone H3 methylation for two allotetraploid and one diploid Brassica species. We have found that the pattern of H3K9me2 in interphase nuclei from root meristematic tissue is comparable within the analyzed species and includes both heterochromatin and euchromatin, but the level of modification differs not only among species but even among nuclei in the same phase of the cell cycle within one species. Moreover, the differences in the level of H3K9me2 are not directly coupled with DNA content in the nuclei and are probably tissue specific. 相似文献
2.
Twelve callus lines of Arabidopsis thaliana were derived from four types of explants excised from diploid plants of two ecotypes (Columbia and Wilna) and autotetraploid plants of the Wilna ecotype. Cytogenetic analysis of the chromosome variation in particular callus lines was carried out for primary culture and callus during 5 months of culture. Ploidy levels of interphase nuclei were estimated by counting the number and size of chromocentres and nuclei of interphase cells. The first polyploid cells in all callus lines were observed during callogenesis. In primary culture the ploidy level ranged between 2 and 15x (10-75 chromosomes). The frequency of polyploid cells was higher in the 5-month old callus culture, but the ploidy level was the same. In the callus lines derived from autotetraploid plants, cells with reduced chromosome number appeared quite frequently along with diploid and polyploid cells. 相似文献
3.
Luchniak P Maluszynska J Olszewska MJ 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2002,40(3):325-330
Experiments were performed on Crepis capillaris callus lines with 0, 1 and 2 B chromosomes and on hairy root lines without or with 1 and 2 B chromosomes. Comparison of HPLC results for DNA from calli differing in number of B chromosomes did not reveal any significant differences in methylation level (30.4 +/- 1.1%, 30.9 +/- 1.2%, 31.7 +/- 1.7% in lines without or with one or two B chromosomes respectively) which could be attributed to the number of B chromosomes. Restriction patterns obtained after DNA digestion with HhaI, HpaII, MspI or HaeIII (i.e. restriction enzymes sensitive to cytosine methylation) were similar in calli and apical root segments and also did not depend on the presence or number of B chromosomes. Methylation of B chromosomes higher than that of A chromosomes was demonstrated by fluorescent in situ nick translation driven by HpaII, MspI or HaeIII in metaphase chromosomes. After short digestion (I and 3 h), B chromosomes, in contrast to A chromosomes, were weakly labelled or not labelled at all, which indicates longer distances between target sequences containing unmethylated cytosine in the former. 相似文献
4.
5.
Bozena Kolano Dorota Siwinska Luz Gomez Pando Joanna Szymanowska-Pulka Jolanta Maluszynska 《Plant Systematics and Evolution》2012,298(1):251-255
The extent and significance of intraspecific genome size variation were analysed in quinoa (Chenopodium quinoa Willd.), a pseudocereal important for human consumption in the Andean region of South America. Flow cytometry, with propidium
iodide as the DNA stain, was used to estimate the genome size of 20 quinoa accessions from Ecuador, Peru, Bolivia, Argentina,
Chile and the USA. Limited genome size variation was found among the analysed accessions. The differences between the accessions
were statistically significant but the maximum inter-accession difference between the populations with the largest and the
smallest genome reached only 5.9%. The largest genome was found in population C4 from Chile (mean 3.077 pg/2C) and the smallest
in the Peruvian population P2 (mean 2.905 pg/2C). The variation was not correlated with collection site; however, the quinoa
accessions analysed in this study belonged to three distinct geographical groups: northern highland, southern highland and
lowland. 相似文献
6.
The chromosome behaviour has been compared in three Crepis capillaris callus culture lines and the roots regenerated from
these calli. The calli were obtained from explants derived from plants without and with two B chromosomes and the hairy roots
were obtained from plants transformed with Agrobacterium rhizogenes. Cytological studies demonstrated that the presence of
additional DNA as B chromosomes or as T-DNA had an influence on the numerical and structural variability of the standard chromosome
in long-term callus cultures and in regenerated organs. The callus with two B chromosomes displayed higher levels of polyploidyzation
than callus without B chromosomes. The roots regenerated from both these calli were only diploid, while roots regenerated
from transformed callus were also polyploid.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Hydrogen bonding in nucleosides and nucleotides 总被引:1,自引:0,他引:1
G.A. Jeffrey H. Maluszynska J. Mitra 《International journal of biological macromolecules》1985,7(6):336-348
An analysis of the hydrogen bonding in 76 nucleoside and 11 nucleotide crystal structures shows that the hydrogen bond lengths fall into well-defined categories according to the nature of the donor or acceptor groups. The shortest bonds are those involving P---OH or O=P groups. For donor groups, the sequence in bond lengths is bonds, which are comparable in length with P---OH …O bonds. The acceptor seqeunce is
P—OH<C—OH< N−H<Ow(H)—H<N(H)—H<C−H
There are ten examples of two centre
H—H…O
O=P<OH2<OH2<O=CO(H)C<N N(H2)C<Cl…<O<S=C
The number of three-centre bonds, about 24%, is comparable to that observed in the carbohydrates and the amino acids. Most hydrogen bonds are involved in short finite chains. Only in the nucleotides are cyclic hydrogen bonding schemes observed. 相似文献
8.
Ribosomal DNA is an effective marker of Brassica chromosomes 总被引:8,自引:0,他引:8
R. Hasterok G. Jenkins T. Langdon R. N. Jones J. Maluszynska 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(4):486-490
Simultaneous fluorescence in situ hybridisation with 5S and 25S rDNA probes enables the discrimination of a substantial number
of chromosomes of the complement of all diploid and tetraploid Brassica species of the ”U-triangle”, and provides new chromosomal landmarks for the identification of some chromosomes of this genus
which were hitherto indistinguishable. Twelve out of 20 chromosomes can be easily identified in diploid Brassica campestris (AA genome), eight out of 16 in Brassica nigra (BB genome), and six out of 18 in Brassica oleracea (CC genome). Furthermore, just two rDNA markers permit 20 out of 36 chromosomes to be distinguished and assigned to either
the A or B genomes of the allotetraploid Brassica juncea, and 18 out of 38 chromosomes identified and assigned to the A or C genomes of the allotetraploid Brassica napus. The number of chromosomes bearing rDNA sites in the tetraploids is not in all cases simply the sum of the numbers of sites
in their diploid ancestors. This observation is discussed in terms of the phylogeny and variability within the genomes of
the species of this group.
Received: 13 September 2000 / Accepted: 1 February 2001 相似文献
9.
The crystal structure of 1,6-anhydro-β-d-mannopyranose, C6H10O5, is orthorhombic, P212121, with a = 10.971(2), b = 13.935(3), c = 9.012(1) Å, V = 1377.76 »3 (MoKα, λ = 0.7107 Å), Z = 8, Dx = 1.563 M.gm−3, Dm = 1.565 M.gm−3. the structure was solved by MULTAN and refined to R(F) = 0.043 for 2355 reflections. The two symmetry-independent molecules in the unit cell have similar conformations, except for the orientation of one of the three hydroxyl groups. The conformation of the pyranose rings is 1C4 distorted towards Eo, and that of the anhydro rings is E. There are significant differences between the two molecules in two of the four C---O bond-lengths. These occur where there are important differences in the hydrogen-bonding environment of the oxygen atoms. The molecules are hydrogen-bonded by three linear and three bifurcated O---H···O interactions which form four-membered loops linked into infinite chains. Empirical force-field calculations with MMI-CARB reproduced the geometry of the molecules within the variations observed experimentally between the two molecules, except for a C---O bond in one of the molecules. The effect of excluding the anomeric effect from the theoretical calculations was not significant. Calculations for an intramolecularly hydrogen-bonded molecule were also carried out as a model for the molecules in a non-polar solvent. 相似文献
10.
The presence of a large number of pollutants, including mutagenic agents in the environment is a problem of a major concern. Rapid progress in plant biotechnology, especially in the development of cell transformation methods, including the production of transformed roots -- 'hairy roots' -- has opened new possibilities to use transformed root cultures in plant bioassays for the evaluation mutagenic effects of different agents. We have used Crepis capillaris hairy roots for evaluation of cytogenetic effects of mutagenic treatment. Effects of maleic acid hydrazide (MH) and X-ray treatment were analysed in chromosomal aberration, sister chromatid exchange (SCE) and TUNEL tests. Comparison of cytogenetic effects in hairy roots and roots of seedlings showed a much higher sensitivity of hairy roots, which makes them convenient material for monitoring DNA damage after mutagenic treatment. 相似文献