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1.
The distribution and stability of the cellular tumor antigen p53 were studied in baby rat kidney cells transformed by region E1 sequences of nononcogenic adenovirus (Ad) type 5 (Ad5) or oncogenic type 12 (Ad12). In transformed cells expressing the large E1B T antigen of Ad5, p53 was associated with this T antigen. The complexed proteins were concentrated in a cytoplasmic body, which has been shown to consist of a cluster of 8-nm filaments (A. Zantema et al., Virology 142:44-58, 1985). In transformed cells expressing the E1B region of Ad12, however, no association between the viral large T antigen and p53 was detectable. In the latter case, both proteins were found almost exclusively in the nucleus. The stability of p53 in both Ad5- and Ad12-transformed cells was increased relative to that in primary cells or cells immortalized by the E1A region only. Thus, the increased stability of p53 in Ad-transformed cells is not caused by association with a viral T antigen, but it correlates with expression of E1B and with morphological transformation.  相似文献   
2.

Background  

The integration of many aspects of protein/DNA structure analysis is an important requirement for software products in general area of structural bioinformatics. In fact, there are too few software packages on the internet which can be described as successful in this respect. We might say that what is still missing is publicly available, web based software for interactive analysis of the sequence/structure/function of proteins and their complexes with DNA and ligands. Some of existing software packages do have certain level of integration and do offer analysis of several structure related parameters, however not to the extent generally demanded by a user.  相似文献   
3.
Cytogenetic analysis was employed in studying the cause of generation of fertile awned forms in the progeny of plants, which were selected from a speltoid somaclonal wheat line monosomic for chromosome 5A (2n = 41 = 20II + I), had speltoid spikes, and were reproduced by self pollination. On cytogenetic and genetic evidence, chromosome 5A was eliminated and the copy number of chromosome 5B increased in the plants examined. The appearance of an extra chromosome 5B is probably caused by nondisjunction of bivalent 5B in the presence of a telocentric originating from the long arm of chromosome 5A. A difference in meiotic segregation was observed for univalent chromosomes 5A and 5B.  相似文献   
4.
H2S+ bacteria responsible for the degradation of sulfur-containing amino acids of fish muscle are currently little used to evaluate the microbiological pal quality of fish. Shewanella putrefaciens greatly predominates in this flora, and was therefore used to define a suitable culture method and medium. Inoculations by the Spiral surface method at 25C, with an incubation of 72h, gave the best counts on a medium containing two sources of sulfur (organic and inorganic) for H2S+ bacteria. The culture medium and the NaCl concentration were determinant in the evaluation of this flora. At present there is no standard medium which meets these requirements.  相似文献   
5.
Twenty-four Triticum aestivum×T. timopheevii hybrid lines developed on the basis of five varieties of common wheat and resistant to leaf rust were analyzed by the use of microsatellite markers specific for hexaploid wheat T. aestivum. Investigation of intervarietal polymorphism of the markers showed that the number of alleles per locus ranged from 1 to 4, depending on the marker (2.5 on average). InT. timopheevii, amplification fragments are produced by 80, 55, and 30% of primers specific to the A, B, and D common wheat genomes, respectively. Microsatellite analysis revealed two major areas of introgression of the T. timopheevii genome: chromosomes of homoeological groups 2 and 5. Translocations were detected in the 2A and 2B chromosomes simultaneously in 11 lines of 24. The length of the translocated fragment in the 2B chromosome was virtually identical in all hybrid lines and did not depend on the parental wheat variety. In 15 lines developed on the basis of the Saratovskaya-29, Irtyshanka, and Tselinnaya-20, changes occurred in the telomeric region of the long arm of the 5A chromosome. Analysis with markers specific to the D genome suggested that introgressions of the T. timopheevii genome occurred in chromosomes of the D genome. However, the location of these markers on T. timopheevii chromosomes is unknown. Our data suggest that the genes for leaf rust resistance transferred from T. timopheevii to T. aestivum are located on chromosomes of homoeological group 2.  相似文献   
6.
Storage proteins, prolamins, were studied in ten introgression lines of common wheat bred with involvement of Triticum timopheevii (Tt) Zhuk. and five commercial hexaploid wheat cultivars. The lines are resistant to leaf rust. A comparative analysis of the storage proteins in the Triticum aestivum L. (Ta) introgression lines and the parental forms allowed us to (1) detect the active genes of prolamins on the chromosomes homeologous groups 1 and 6 in the introgression lines of T. aestivum and T. timopheevii; (2) clarify their origin; (3) identify the chromosome attribution of the products; (4) estimate the degree of introgression and postulate the introgression mechanisms; and (5) predict the bread-making quality of these introgression lines.  相似文献   
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8.
To study pigmentation, we have reconstructed an epidermis ex vivo with keratinocytes and melanocytes. Keratinocytes and melanocytes were grown first in primary cocultures and separately in secondary cultures, then seeded on a dead deepidermized dermis (Pruniéras type) at a 1:20 melanocyte/keratinocyte ratio. Reconstructed epidermis were grown in a special medium enriched with calcium and fetal bovine serum lifted for 15 days at the air-liquid interface. Using histology, immunohistochemistry and electron microscopy we have shown an excellent level of differentiation of the reconstructed epidermis and a physiologic distribution of dendritic melanocytes in the basal layer capable of melanosome transfer to keratinocytes. UVB irradiation 0.15 J/cm2× 5 consecutive days increased melanocyte numbers and stimulated pigmentation as evidenced macroscopically and microscopically and at the biochemical level. Following UVB irradiation melanosome transfer was markedly increased and isolated or clumps of melanosomes were seen in the basal layers as well as in the stratum corneum. This model allows the study of the physiology of pigmentation ex vivo.  相似文献   
9.
Summary Tissue culture of the Zea mays inbred line A188 resulted in the regeneration of plants having a high level of phenotypic variation compared to seed-grown control plants. To determine how such variation was induced and whether this could be related to specific in vitro culture methods, callus cultures were established and maintained on different, commonly used culture media. Plants were regenerated and the genomic DNA of callus cultures and regenerants analysed for RFLP differences. The results show that regardless of the gene probe used, callus formation resulted in significant deviations from the DNA pattern normally found in seed-grown control plants. Alterations in gene copy number also occurred. As differentiation and organogenesis began, the level of DNA variation fell, and most of the regenerated plants showed a genetic similarity to the controls; those with RFLP differences were the somaclonal variants.  相似文献   
10.
To understand the contribution of epidermal melanocytes in the proteolytic potential of human skin, we have studied melanocytes grown in a low-serum medium deprived of phorbol esters, cholera toxin, and other non-physiological supplements. We focused on the plasminogen activation system and certain matrix metalloproteinases (gelatinases). Supposing that the proteolytic activity of cells can influence binding to collagen matrix and its reorganization, we have analyzed these parameters as well. We found that human melanocytes secreted tissue-type plasminogen activator and utilised it to generate cell-bound plasmin. No urokinase-type plasminogen activator was detected in the cultures but its receptor was found in cell extracts. Both the 72 kDa and 92 kDa gelatinases were secreted by the cells and in equal amounts. In addition, melanocytes secreted the wide-spectrum proteinase inhibitor alpha-2-macroglobulin. Melanocytes cast into collagen matrices retained a rounded morphology, did not extend processes, and were unable to contract collagen lattices. As a control, these parameters were investigated in parallel in cultures of human keratinocytes, dermal fibroblasts, and two melanoma cell lines. The obtained characteristics suggest that normal human melanocytes are proteolytically active cells. This function may pertain to skin physiology and pathophysiology.  相似文献   
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