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991.
992.
Mojmír Vaek Jan Kube
ka Jií Peterka Martin ech Vladislav Dratík Milan Hladík Marie Prchalov Jaroslava Frouzov 《International Review of Hydrobiology》2004,89(4):352-362
The large‐scale spatial distribution of fish was investigated within a morphometrically simple canyon‐shaped reservoir with a single major tributary and a longitudinal trophic gradient (Římov Reservoir, Czech Republic). Samples of fish were taken by Nordic survey gill nets (several mesh sizes from 8 to 70 mm knot to knot) installed as surface nets at several offshore areas located along the longitudinal axis of the reservoir. Surveys were carried out in late summer during 1999–2003. An obvious distribution gradient of fish was revealed along the longitudinal axis of the Římov Reservoir. The total relative fish abundance and biomass (catch per unit effort) decreased considerably from the upstream end of the reservoir toward the dam. Roach (Rutilus rutilus), bleak (Alburnus alburnus) and bream (Abramis brama) comprised the bulk of catches at all areas. Enhanced dominance of bream was observed in the fish assemblage at the uppermost, more eutrophic area of the reservoir. The highest number of fish species and the highest abundance of young‐of‐the‐year fish were also observed in the tributary area. In the downstream part of the reservoir, gill net surveys along the vertical depth profiles indicated that offshore fish occupied mostly the epilimnion. Extreme flood events affected the Římov Reservoir, however, it seemed they had no significant impact on the gradients described. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
993.
Jindrich Cinatl Jr. Jaroslav Cinatl Pablo Hernáiz Driever Holger Rabenau Milos Novak Milan Stefanik Bernhard Kornhuber Hans-Wilhelm Doerr 《Cell biology international》1994,18(4):271-278
The effects of aphidicolin, a specific inhibitor of DNA polymerase α, on cell growth, DNA synthesis and myogenic differentiation in the human alveolar rhabdomyosarcoma cell line KFR were studied. The treatment with aphidicolin at 5 × 10−6 M concentration, which completely inhibited DNA synthesis and cell growth, induced morphological differentiation of small mononuclear cells to elongated, multinucleated (myotube-like) structures. The morphological differentiation was accompanied by the expression of skeletal muscle myosin; about 30% myosin-positive cells were observed after 14 days of treatment, compared to 2.3% in untreated cultures. The results showed that aphidicolin induces differentiation of human rhabdomyosarcoma cells and that multinucleated myotube-like elements may develop simply by cell fusion without cell division and DNA synthesis. 相似文献
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995.
996.
Jasmina Zdravković Marković Živoslav Mijatović Mirjana Zečević Bogoljub Zdravković Milan 《Acta Physiologiae Plantarum》2000,22(3):261-265
The genetic analysis of 5 tomato hybrids (Danubius F1, Luna F1, Lido F1, Balkan F1 and Mi-10 F1) was made. We produced their F1, F2, BC1 and BC2 generations and analysed their yield (on the first three flower branches) as well as some of the yield components of tomato
fruits (mean fruit weight, mean fruit weight on the first flower branch, fruit length, fruit width, and number of locules).
In order to estimate the gene effects, we applied the additive-dominance mode with three and six parameters. Epistatic gene
effects were estimated by applying the six-parameter mode (Mather and Jinks 1982). As for yield and yield components, there
were significant differences between the mean values of parents and their progeny. On the basis of the investigated genetic
parameters, the obtained results suggested that the additive and dominance gene effects prevailed in the yield and yield components
(Danubius F1, Luna F1, Lido F1, Mi-10 F1), whereas epistatic gene effects were excluded. As for the hybrid Balkan F1, we recorded significant gene effects, both the additive and the dominance ones in the yield inheritance: additive x additive
and dominance x dominance (with the negative sign). The estimated values of the epistatic gene effects were the most prominent
in inheriting the feature average fruit weight on the first flower branch — additive x dominance gene effects. They represented
the most frequent type of the interallele interaction recorded in the investigated hybrids. 相似文献
997.
Branko Jovčić Zorica Lepšanović Jelena Begović Brankica Filipić Milan Kojić 《Antonie van Leeuwenhoek》2014,105(3):613-618
New Delhi metallo-β-lactamase producing Pseudomonas aeruginosa isolates are of special interest since P. aeruginosa is a major cause of nosocomial infections, the treatment of which could now be jeopardized, especially in developing countries. Six additional NDM-1 positive P. aeruginosa clinical isolates belonging to two different genotypes were shown to be plasmid-free. PFGE-hybridization experiments revealed the chromosomal location of the bla NDM-1 gene. Restriction analysis and hybridization revealed that two copies of the bla NDM-1 gene are present in the genomes of all tested isolates, as in previously characterized P. aeruginosa MMA83. Moreover, it was shown that increasing imipenem concentration did not have the effect on copy number of the bla NDM-1 gene in the genome of P. aeruginosa MMA83. 相似文献
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Detection of a Trimeric Human Immunodeficiency Virus Type 1 Gag Intermediate Is Dependent on Sequences in the Matrix Protein, p17 总被引:4,自引:4,他引:4
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Yuko Morikawa Wei-Hong Zhang David J. Hockley Milan V. Nermut Ian M. Jones 《Journal of virology》1998,72(9):7659-7663
Previous studies have shown that single amino acid changes in the amino-terminal matrix (MA) domain, p17, of the human immunodeficiency virus type 1 Gag precursor Pr55, can abrogate virion particle assembly. In the three-dimensional structure of MA such mutations lie in a single helix spanning residues 54 to 68, suggesting a key role for this helix in the assembly process. The fundamental nature of this involvement, however, remains poorly understood. In the present study, the essential features of the MA helix required for virus assembly have been investigated through the analysis of a further 15 site-directed mutants. With previous mutants that failed to assemble, residues mapped as critical for assembly were all located on the hydrophobic face of the helix and had a key role in stabilizing the trimeric interface. This implies a role for the MA trimer in virus assembly. We support this interpretation by showing that purified MA is trimeric in solution and that mutations that prevent virus assembly also prevent trimerization. Trimerization in solution was also a property of a larger MA-capsid (CA) Gag molecule, while under the same conditions CA only was a monomer. These data suggest that Gag trimerization driven by the MA domain is an intermediate stage in normal virion assembly and that it relies, in turn, on an MA conformation dependent on the hydrophobic core of the molecule. 相似文献