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Microsatellites are widely distributed in plant genomes and comprise unstable regions that undergo mutational changes at rates much greater than that observed for non-repetitive sequences. They demonstrate intrinsic genetic instability, manifested as frequent length changes due to insertions or deletions of repeat units. Detailed analysis of 1600 clones containing genomic sequences of Vicia bithynica revealed the presence of microsatellite repeats in its genome. Based on the screening of a partial DNA library of plasmids, 13 clones harbouring (GA/TC)n tracts of various lengths of repeated motif were identified for further analysis of their internal sequence organization. Sequence analyses revealed the precise length, number of repeats, interruptions within tracts, as well as sequence composition flanking the repeat motifs. Representative plasmids containing different lengths of (GA/TC)n embedded in their original flanking sequence were used to investigate the genetic stability of the repeats. In the study presented herein, we employed a well characterised and tractable bacterial genetic system. Recultivations of Escherichia coli harbouring plasmids containing (GA/TC)n inserts demonstrated that the genetic instability of (GA/TC)n microsatellites depends highly on their length (number of repeats). These observations are in agreement with similar studies performed on repetitive sequences from humans and other organisms.
Peafowl (Pavo cristatus), similarly to other Galliformes, are particularly susceptible to infection by Mycobacterium avium. Peafowl differ from other Galliformes in the clinical image of the infection, with dominating respiratory signs. Occurrence of severe and sustained dyspnoea in peafowl raises suspicion of mycobacteriosis, which, however, is not always easy to confirm. In the cases described here, mycobacteria were detected in direct swabs from the trachea of two individuals, and cultures were conducted on the Löwenstein-Jensen medium. In one individual, no mycobacteria were found in tracheal swabs stained by the Ziehl-Neelsen method, despite the presence of clear clinical signs. The fourth case was a young bird submitted for necropsy. The cause of death was a mechanical trauma, but scarce caseous nodules typical of mycobacteriosis were found in the liver, spleen and lungs. The Mycobacterium avium isolates obtained from those cases were compared using (CCG)4-based PCR. A high similarity of three isolates of Mycobacterium avium subsp. avium was observed, two of which were derived from peafowl originating from the same farm, while the isolate from the fourth bird differed significantly and was identified by sequencing as Mycobacterium avium subsp. paratuberculosis.
 We cloned and sequenced the cspA-like gene from a psychrotrophic Antarctic soil-dwelling bacterial strain Psychrobacter sp. B6. The gene is 213 bp long and shows 99% and 98% sequence identity with the Psychrobacter cryohalolentis K5 gene encoding a cold-shock DNA-binding domain protein and the Psychrobacter arcticus transcriptional regulator-CspA gene, respectively. The protein encoded by the Psychrobacter sp. B6 cspA-like gene shows 100% identity with the two proteins mentioned above, and also 61% sequence identity with CspB from Bacillus subtilis and Csp from Bacillus caldolyticus, and 56% — with Escherichia coli CspA protein. A three-dimensional model of the CspA-like protein from Psychrobacter sp. B6 was generated based on three known structures of cold shock proteins: the crystal structure of the major cold shock protein from Escherichia coli (CspA), the NMR structure of the latter protein, and the NMR structure of Csp from Thermotoga maritima. The deduced structure of the CspA-like protein from Psychrobacter sp. B6 was found to be very similar to these known structures of Csp-like proteins.
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