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Bacteriophage λ is not able to lysogenise the Escherichia coli rpoA341 mutant. This mutation causes a single amino acid substitution Lys271Glu in the C-terminal domain of the RNA polymerase α subunit (αCTD). Our previous studies indicated that the impaired lysogenisation of the rpoA341 host is due to a defect in transcriptional activation by the phage CII protein and suggested a role for αCTD in this process. Here we used a series of truncation and point mutants in the rpoA gene placed on a plasmid to investigate the process of transcriptional activation by the CII gene product. Our results indicate that amino-acid residues 265, 268 and 271 in the α subunit may play an important role in the CII-mediated activation of the pE promoter (most probably residue 271) or may be involved in putative interactions between αCTD and an UP-like element near pE (most probably residues 265 and 268). Measurement of the activity of pE-lacZ, pI-lacZ and paQ-lacZ fusions in the rpoA+ and rpoA341 hosts demonstrated that the mechanism of activation of these CII-dependent promoters may be in each case different.
 Three dimensional domain swapping is one of the mechanisms involved in formation of insoluble aggregates of some amyloidogenic proteins. It has been proposed that proteins able to swap domains may share some common structural elements like conformationally constrained flexible turns/loops. We studied the role of loop L1 in the dimerization of human cystatin C using mutational analysis. Introduction of turn-favoring residues such as Asp or Asn into the loop sequence (in position 57) leads to a significant reduction of the dimer fraction in comparison with the wild type protein. On the other hand, introduction of a proline residue in position 57 leads to efficient dimer formation. Our results confirm the important role of the loop L1 in the dimerization process of human cystatin C and show that this process can be to some extent governed by single amino acid substitution.
Application of vegetable fat in experimental production of comminuted, scalded sausages was studied in this paper. An essential part (20,35 or 50%) of animal fat was substituted with food grade rape oil, and the influence of such substitution on the quality of final products was determined. Results of sensoric examination showed no significant differences between control (without oil) and oil contained sausages with substitution level equal to 35%.
This study evaluated the applicability of particles of white mustard straw as a substitute of wood chips in the manufacture of particle boards, resinated with UF resin. The scope of work included the determination of suitability of mustard straw in the manufacture of particle boards, the manufacture of boards with different proportions of straw and the determination of their basic physico-mechanical properties. Produced single-layer particle boards contained 10, 25, 50, 75 and 100% mustard particles in relation to chip mass. Recorded results indicated that straw of white mustard may constitute a valuable substitute of wood chips in the production of general use particle boards and interior boards, including furniture, used under dry conditions. It was also shown that partial substitution of wood chips with particles of mustard straw in case of boards with density reduced by 30%.
Tetraploid rye was crossed with different tetraploid triticale lines. The F₁ generation of tetraploid rye × tetraploid triticale hybrids was backcrossed with 4x rye. After backcrossing, all BC₁-F₁ plants were subjected to open pollination, whereas in the BC₁-F₂ generations only plants with wheat chromosomes in their karyotypes were open-pollinated. Substitution, addition and addition-substitution lines of wheat chromosomes in tetraploid rye were isolated from the F₂ and F₃ of BC₁. In 60 plants of BC₁-F₂, 59 chromosomes from the A genome and 9 from the B genome of wheat were recovered. The wheat chromosomes were monosomic except for five plants which were disomic, viz. 1A and 5A in two plants each, and a translocated 3AS/5AL in one plant. In 235 BC₁-F₃ plants, 174 wheat addition and substitution chromosomes were found, 143 from the A genome and 31 from the B genome. All wheat chromosomes except 3A from the A genome and four chromosomes from the B genome - 2B, 3B, 5B and 7B were recovered. The number of substitutions ranged from one to four per plant, only two plants having four. In the group of addition plants the number of added wheat chromosomes ranged from one to two, and in the case of addition-substitution plants — from two to four. Wheat chromosomes occurred in monosomic form, except 10 plants. Six substitution plants were disomic for 1 A, 2A, 5A, 7A, 2B and 3B, respectively. One was disomic for 1A and 5A in two addition plants. Two addition-substitution plants were double disomic: 1A and 5A - in one, and 1A and 3B in the other. In the BC₁-F₃ generation, 23 different translocations were found, four of which occurred between wheat chromosomes and the remaining 19 - between wheat and rye chromosomes. Translocated chromosomes were monosomic, except four plants. Two of them were disomic for 3AS/4RL, one for 4AS/4RS and one for 7AS/7RS. The fertility of both addition and substitution plants ranged from 0 to 38.0 seeds/spike, regardless of the chromosome number, with a mean of 9.61 seeds/spike. Plants with 28 chromosomes showed singnificantly higher fertility than plants with 29 and more chromosomes, except additoion plants with chromosomes 5A and 5B. The analysis of the influence of particular wheat chromosomes on plant fertility showed that both substitution and addition plants with chromosome 6A had the highest average fertility, while plants with chromosome 2B in substitution lines as well as plants with chromosome 2A in addition and addition-substitution lines had the lowest fertility.
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