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- Author or Editor: M. Molnár x
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The multicolour genomic in situ hybridization (mcGISH) method was improved in order to visualize the U b and M b genomes of Aegilops biuncialis Vis. (2n=4x=28, U b U b M b M b ). Hybridization probes prepared from the diploid U and M genome donors, Ae. umbellulata and Ae. comosa , resulted in clear hybridization signals on the U and M chromosomes in Ae. biuncialis . The random primed labelling method made it possible to decrease the blocking ratio to 1:30. McGISH allowed the simultaneous discrimination of individual Ae. biuncialis genomes and wheat chromosomes in γ-irradiated Triticum aestivum-Ae. biuncialis amphiploids (2n=70; AABBDDU b U b M b M b ). Dicentric chromosomes, terminal and interstitial translocations and centric fusions were detected in the irradiated generation. The irradiation-induced wheat- Ae. biuncialis intergenomic translocations will facilitate the successful introgression of useful agronomic traits into bread wheat.
Abstract
Thermic detectors are seldom used in analytical laboratories, in spite of their advantageous properties. Their theoretical basis provides simple relations and useful equations for the design and construction of thermic liquid analyzers. In this paper a home-made detector system was used for the continuous determination of hydrochloric acid. The results were in accordance with the theoretical considerations.
One way of incorporating useful traits from Aegilops biuncialis (2n=4x=28, U b U b M b M b ) into wheat ( Triticum aestivum L. 2n=6x=42, AABBDD) is to develop first addition then translocation lines. The 2M b , 3M b , 7M b , 3U b , 5U b and 5U b /6U b wheat- Ae. biuncialis addition lines were produced in Martonvásár. To facilitate the exact identification of the addition lines, it was necessary to analyse the fluorescence in situ hybridisation patterns of the parental wheat genotype, Ae. biuncialis and its diploid progenitors ( Ae. umbellulata 2n=2x=14, UU and Ae. comosa 2n=2x=14, MM). The great genetic variability of the Aegilops species causes polymorphism in the fluorescence in situ hybridisation (FISH) patterns of the individual chromosomes. Due to the high level of FISH polymorphism, it is advisable to confirm the identification of the Ae. biuncialis chromosomes with the help of molecular (microsatellite, SSR) markers, so 119 wheat SSR markers were tested on Aegilops biuncialis , on Ae. geniculata (2n=4x=28, U g U g M g M g ), on five wheat- Ae. biuncialis addition lines (2M b , 3M b , 7M b , 3U b , 5U b ) and on an addition series of wheat- Ae. geniculata in order to select SSR markers specific to the U and M genomes of Ae. biuncialis and Ae. geniculata .
In this study we introduce new rock physical models which describe the pressure dependence of seismic velocity and quality factor. The models are based on the idea (accepted in the literature) that microcracks in rocks are opened and closed under the change of pressure. The models were applied to acoustic P wave velocity data measured on core samples originated from oil-drilling wells (27 samples) and also seismic velocity and quality factor data sets published in international literature. During the measurements the pulse transmission and the spectral ratio techniques were used. Measurements were carried out at various incremental pressures and parameters of the models were determined by linearized inversion methods. The calculated data matched accurately with measured data proving that the new rock physical models apply well in practice.
Fluorescence in situ hybridization (FISH) is the most versatile and accurate molecular cytogenetic technique for determining euchromatic-heterochromatic boundaries and the locations of repetitive and single-copy DNA sequences and of chromosome-specific BAC clones on chromosomes. The combination of cytogenetic and genetic methods yields a highresolution physical map. FISH allows direct mapping of specific DNA sequences inside the cell (interphase nuclei), along meiotic pachytene chromosomes and isolated chromatin (DNA fibres). The increased sensitivity of the technique and its ability to detect gene locations provide a powerful research tool for genetic and pre-breeding studies. FISH-based physical mapping plays an important role and is increasingly used for studies at the cytological level on the chromatin organization that controls gene expression and regulation. The present minireview describes some of the benefits of alternative FISH-based techniques and their application for studying plant chromosomes and genomes.
Several molecular markers have been reported for the detection of the 1RS chromosome arm. The aim of the present experiments was to study the reliability and reproducibility of six molecular markers specific to the 1RS rye chromosome (GPI, Bmac213, 5S, IAG95, SCM9 and RMS13) in distinguishing between wheat genotypes with and without the 1BL.1RS or 1AL.1RS translocations. In the course of the analysis, PCR products of the expected size were obtained with all the markers, which were found to give a reliable indication of the presence of the 1RS chromosome arm in the wheat genome.
The relation between isoperimetric properties and Laplacian spectra of weighted graphs is investigated. The vertices are classified into k clusters with „few" inter-cluster edges of „small" weights (area) and „similar" cluster sizes (volumes). For k=2 the Cheeger constant represents the minimum requirement for the area/volume ratio and it is estimated from above by v?1(2-?1), where ?1 is the smallest positive eigenvalue of the weighted Laplacian. For k?2 we define the k-density of a weighted graph that is a generalization of the Cheeger constant and estimated from below by Si=1 k-1?i and from above by c2 Si=1 k-1 ?i, where 0<?1=…=Sk-1 are the smallest Laplacian eigenvalues and the constant c?1 depends on the metric classification properties of the corresponding eigenvectors. Laplacian spectra are also related to canonical correlations in a probabilistic setup.
