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951.
Claire R. Quilter Sarah C. Blott Alan J. Mileham Nabeel A. Affara Carole A. Sargent Darren K. Griffin 《Mammalian genome》2002,13(10):588-594
A combination of FISH and RH mapping was used to study the evolution of sex chromosome genes in the pig. In total, 19 genes
were identified, including 3 PAR genes (STS, KAL, PRK). The gene order of the porcine X Chromosome (Chr) closely resembled
the human X Chr (PRK/STS/KAL–AMELX–EIF2s3X/ZFX–USP9X–DBX–SMCX), suggesting that the porcine X has undergone very little rearrangement
during evolution. For the porcine Y Chr, two linkage groups of 10 NRY genes were found, and the following order was established:
Ypter–(AMELY–EIF2S3Y/ZFY–USP9Y–DBY/UTY)–(TSPY–SMCY–UBE1Y–SRY)–CEN. This gene order showed greater conservation with the murine
Y than with the human Y Chr. In addition, all porcine Y Chr genes mapped to Yp, which is similar to the mouse and included
EIF2s3Y and UBE1Y, which are not present in humans. Interestingly, complete conservation of X/Y homologous gene order was
found between the pig X and Y Chrs, indicating that the porcine Y Chr has not undergone extensive reorganisation with respect
to the X. This suggests that the order of the X/Y homologous genes of the porcine X and Y Chrs may closely resemble the ancestral
gene order of the eutherian sex chromosomes. 相似文献
952.
Xuejun Cao XingYan Wu Tong Wu Keming Jin Byung Ki Hur 《Biotechnology and Bioprocess Engineering》2001,6(3):200-204
In this study, nanofiltration was applied to the concentration of the 6-aminopenicillinic acid (6-APA) from bioconverted penicillin
solution and also to its mother liquor. The 6-APA in the solution was concentrated from 0.211 mol/L to 0.746 mol/L by nanofiltration.
The final maximum concentration was 3.6 times higher than the initial concentration and the recovery yield was 97% to 99%
of the original 6-APA. The concentrated solution was crystallized with the yields of 88.9–90.2% and the purity of the crystallized
product was about 98%. The concentration of 6-APA in the mother liquor after crystallization was 0.014 mol/L and thus was
concentrated 20–30 fold by nanofiltration and crystallization. The recovery of 6-APA was over 98%. The salts contained in
the mother liquor, such as NH4Cl and KCl, could be removed by allowing them to permeate through the membrane. 相似文献
953.
This paper demonstrates the use of phenology models mapped over the landscape as a tool in support of risk assessments for nonindigenous plant pests. Drawing on the relationship between pest development and temperature, the approach uses gridded sequential interpolated temperatures at a resolution of 1 km, linked with phenology models, to predict the potential for a pest to develop throughout the landscape. The potential for establishment of Colorado beetle (Leptinotarsa decemlineata) in England and Wales was used as an illustration. The likelihood of the pest completing a single generation during a 30‐year period (1961–90) was computed. Summaries of phenology, based firstly upon point temperature series from weather stations and secondly upon temperatures interpolated across the landscape, were compared. The results revealed that the use of point data led to a 70% likelihood of over‐estimating the area at risk from year to year. In the case of average long‐term risk however, the point‐based and landscape‐wide distributions of establishment potential were similar. We demonstrate how the use of phenology models running on a daily time scale provides date based results, so allowing outputs to be tied in with periods in the cropping cycle. The application of daily data in computing the phenological results, unlike the main body of published work on pest risk assessment which uses averaged monthly data, reflects more fully the underlying variability and degrees of sensitivity of the pest to changes in weather. 相似文献
954.
Quantitative amplification of single-stranded DNA (QAOS) demonstrates that cdc13-1 mutants generate ssDNA in a telomere to centromere direction 总被引:2,自引:0,他引:2 下载免费PDF全文
We have developed a method that allows quantitative amplification of single-stranded DNA (QAOS) in a sample that is primarily double-stranded DNA (dsDNA). Single-stranded DNA (ssDNA) is first captured by annealing a tagging primer at low temperature. Primer extension follows to create a novel, ssDNA-dependent, tagged molecule that can be detected by PCR. Using QAOS levels of between 0.2 and 100% ssDNA can be accurately quantified. We have used QAOS to characterise ssDNA levels at three loci near the right telomere of chromosome V in budding yeast cdc13-1 mutants. Our results confirm and extend previous studies which demonstrate that when Cdc13p, a telomere-binding protein, is disabled, loci close to the telomere become single stranded whereas centromere proximal sequences do not. In contrast to an earlier model, our new results are consistent with a model in which a RAD24-dependent, 5′ to 3′ exonuclease moves from the telomere toward the centromere in cdc13-1 mutants. QAOS has been adapted, using degenerate tagging primers, to preferentially amplify all ssDNA sequences within samples that are primarily dsDNA. This approach may be useful for identifying ssDNA sequences associated with physiological or pathological states in other organisms. 相似文献
955.
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957.
Cardiac fibroblasts contribute to the structure and function of the myocardium. However their involvement in electrophysiological processes remains unclear; particularly in pathological situations when they proliferate and develop fibrosis. We have identified the connexins involved in gap junction channels between fibroblasts from adult mouse heart and characterized their functional coupling. RT-PCR and Western blotting results show that mRNA and proteins of connexin40 and connexin43 are expressed in cultured cardiac fibroblasts, while Cx45 is not detected. Analysis of gap junctional communications established by these connexins with the gap-FRAP technique demonstrates that fibroblasts are functionally coupled. The time constant of permeability, k, calculated from the fluorescence recovery curves between cell pairs is 0.066 ± 0.005 min− 1 (n = 65). Diffusion analysis of Lucifer Yellow through gap junction channels with the scrape-loading method demonstrates that when they are completely confluent, a majority of fibroblasts are coupled forming an interconnecting network over a distance of several hundred micrometers. These data show that cardiac fibroblasts express connexin40 and connexin43 which are able to establish functional communications through homo and/or heterotypic junctions to form an extensive coupled cell network. It should then be interesting to study the conditions to improve efficiency of this coupling in pathological conditions. 相似文献
958.
This paper reviews hypotheses about roles of angiogenesis in the pathogenesis of inflammatory disease in two organs, the synovial joint and the lung. Neovascularisation is a fundamental process for growth and tissue repair after injury. Nevertheless, it may contribute to a variety of chronic inflammatory diseases, including rheumatoid arthritis, osteoarthritis, asthma, and pulmonary fibrosis. Inflammation can promote angiogenesis, and new vessels may enhance tissue inflammation. Angiogenesis in inflammatory disease may also contribute to tissue growth, disordered tissue perfusion, abnormal ossification, and enhanced responses to normal or pathological stimuli. Angiogenesis inhibitors may reduce inflammation and may also help to restore appropriate tissue structure and function. 相似文献
959.
960.
S. S. Weinreich Bogda Hoebe-Hewryk A. R. van der Horst Claire J. P. Boog Pavol Ivanyi 《Immunogenetics》1997,46(1):35-40
Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated
enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility
complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among β2-microglobulin (β2m) knockout littermates with or without transgenes for HLA-B*2702 and human β2m. In the knockout phenotype lacking β2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of β2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding
that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order
to increase disease susceptibility, B*2702 must be coexpressed with mouse β2m (mo-β2m). In contrast, when HLA-B*2702 is expressed with β2m of human origin, disease susceptibility is not affected. Thus, both H2b-derived class I heterodimers and HLA-B*2702/mo-β2m heterodimers contribute to ANKENT susceptibility. 相似文献