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61.
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Paul G. McGuire Helen M. Walker-Caprioglio Sally A. Little Linda J. McGuffee 《In vitro cellular & developmental biology. Animal》1993,29(2):135-139
Summary The structure and function of vascular smooth muscle cells have been extensively investigated with the aid of in vitro culture
techniques. The majority of studies have utilized aortic tissue as the source of cells. We present here a method for isolating
and culturing smooth muscle cells of the rat superior mesenteric artery, an elasto-muscular vessel that is structurally and
functionally different from the aorta. Cells were isolated from partially digested explants and characterized by immunochemical
and biochemical techniques. Unlike cultured fibroblasts, the cultured cells stained positive for smooth muscle specific actin.
The cells also produced laminin and type IV collagen in culture. This method provides a means for the isolation of large numbers
of viable smooth muscle cells from the superior mesenteric artery which can be propagated in culture for in vitro study. 相似文献
64.
Lawrence Cris W.; Little Pamela A.; Little Brian W.; Glushka John; van Halbeek Herman; Alhadeff Jack A. 《Glycobiology》1993,3(3):249-259
The N-glylycans have been removed by peptide-N-glycosidase F(PNGase F) from purified human non-secretory RNases derivedfrom kidney, liver and spleen. The spleen RNase was purifiedby two procedures, one of which did not include the usual acidtreatment step (0.25 M H2SO4, 45 min, 4C), to determine ifacid treatment alters the carbohydrate moieties. TheN-glycansof the RNases were fractionated by Bio-Gel P-4 chromatographyand analysed by 600 MHz 1H-NMR spectroscopy and electrospraymass spectrometry. All four non-secretory RNase preparationscontained the following structures: The relative amounts of the trisaccharide, pentasaccharide andhexasaccharide appeared to vary slightly in the different tissueRNases. The overall results indicate: (i) that acid treatmentduring purification does not alter the N-glycans of non-secretoryRNases; (ii) that the N-glycans from kidney, liver and spleennon-secretory RNases are very similar, if not identical, toone another, but different from the N-glycan structures reportedfor secretory RNase. N-glycans non-secretory RNases 相似文献
65.
Hunted and unhunted populations of greywing francolin Francolinus africanus have been studied in the eastern Cape Province of South Africa in order to understand the effects of hunting on the demography and genetic structure of these populations. Greywing population density cycled annually for both hunted and unhunted populations. However, there was an apparent pulse of immigration of sub-dominant birds, and earlier reproduction, in the hunted populations immediately after the winter hunting season. Average levels of allozyme heterozygosity (H) for hunted and unhunted populations were both 0.076, and although the proportion of polymorphic loci per sample and the mean number of alleles per locus for each sample were lower for the hunted populations than for the unhunted populations, these differences were not significant. However, the hunted populations displayed higher levels of outbreeding (lower F
IS and F
IT values) than those for unhunted populations. Therefore, it is concluded that although greywing francolin populations contain relatively high levels of genetic heterogeneity, it is probably the increased levels of local immigration following hunting which reduces the effects of any reduction in genetic variation due to a decrease in local population size from hunting. 相似文献
66.
Somatic mutations in cancer patients are inherently sparse and potentially high dimensional. Cancer patients may share the same set of deregulated biological processes perturbed by different sets of somatically mutated genes. Therefore, when assessing the associations between somatic mutations and clinical outcomes, gene-by-gene analysis is often under-powered because it does not capture the complex disease mechanisms shared across cancer patients. Rather than testing genes one by one, an intuitive approach is to aggregate somatic mutation data of multiple genes to assess their joint association with clinical outcomes. The challenge is how to aggregate such information. Building on the optimal transport method, we propose a principled approach to estimate the similarity of somatic mutation profiles of multiple genes between tumor samples, while accounting for gene–gene similarities defined by gene annotations or empirical mutational patterns. Using such similarities, we can assess the associations between somatic mutations and clinical outcomes by kernel regression. We have applied our method to analyze somatic mutation data of 17 cancer types and identified at least five cancer types, where somatic mutations are associated with overall survival, progression-free interval, or cytolytic activity. 相似文献
67.
A major difference between the divergence patterns within the lines-1 families in mice and voles 总被引:3,自引:0,他引:3
Vanlerberghe F; Bonhomme F; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1993,10(4):719-731
L1 retroposons are represented in mice by subfamilies of interspersed
sequences of varied abundance. Previous analyses have indicated that
subfamilies are generated by duplicative transposition of a small number of
members of the L1 family, the progeny of which then become a major
component of the murine L1 population, and are not due to any active
processes generating homology within preexisting groups of elements in a
particular species. In mice, more than a third of the L1 elements belong to
a clade that became active approximately 5 Mya and whose elements are >
or = 95% identical. We have collected sequence information from 13 L1
elements isolated from two species of voles (Rodentia: Microtinae: Microtus
and Arvicola) and have found that divergence within the vole L1 population
is quite different from that in mice, in that there is no abundant
subfamily of homologous elements. Individual L1 elements from voles are
very divergent from one another and belong to a clade that began a period
of elevated duplicative transposition approximately 13 Mya. Sequence
analyses of portions of these divergent L1 elements (approximately 250 bp
each) gave no evidence for concerted evolution having acted on the vole L1
elements since the split of the two vole lineages approximately 3.5 Mya;
that is, the observed interspecific divergence (6.7%-24.7%) is not larger
than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses
showed no clustering into Arvicola and Microtus clades.
相似文献
68.
1.5-Mb YAC Contig in Xq28 Formatted with Sequence-Tagged Sites and Including a Region Unstable in the Clones 总被引:3,自引:0,他引:3
Giuseppe Palmieri Giovanna Romano Amelia Casamassimi Michele D'Urso Randall D. Little Fatima E. Abidi David Schlessinger Maria Lagerstrm Helena Malmgren Marie-Louise Steen-Bondeson Ulf Pettersson Ulf Landegren 《Genomics》1993,16(3)
A contig of 20 yeast artificial clones (YACs) has been assembled across 1.5 Mb of Xq28 and formatted with nine previously reported probes and nine STSs developed from the sequence of probes and end fragments of YACs. YAC end fragments were obtained by subcloning, Alu-vector PCR, or primer-ligation PCR methods. Eighteen of the YACs were recovered from a library specific for Xq24-q28; two that fill a gap were obtained from a second library made from total human DNA. One region, containing probes pX78c and 2A1.1, was unstable in YACs, but it was possible to generate a self-consistent map of DNA over the entire contig. Overlaps were confirmed by Southern blot analyses of YAC DNAs, and pulsed-field gel electrophoresis confirmed the extent of the contig and identified at least four CpG islands in the region. 相似文献
69.
Synchronously dividing cultures of the unicellular green alga Scenedesmus obtusiusculus were cultivated for 24 or 70 h in medium high (1000 μM) or low (60 μM) in phosphorus. Aliquots of AlCl3 (0, 37, 74, 111, 148, 185, or 222 μmol) were added daily to 1 l cell suspension at the end of the cell division phase. Algae were also grown in media with different pH, adjusted with HCl, in the absence of AlCl3 .
Effects of Al on cell metabolism vary with the intracellular Al concentration and with the concentration of Al available per cell. When the concentration of phosphorus is low, internal concentrations of Al are high and the chlorophyll content and the net dry matter production per cell increase, whereas the photosynthesis and the cell division are increased. Presence of Al in a low P medium decreases the pH of the medium down to 4.5. There are only small effects of Al in the presence of P, due to precipitation of most of the Al with P in the medium.
Despite the Al-induced decrease of the pH of the culture medium, effects caused by Al cannot be explained as a pH effect. Instead, the Al effect may, at least to some extent, be related to a decrease in availability of P in the metabolism, due to formation of aluminium phosphate inside the cell. 相似文献
Effects of Al on cell metabolism vary with the intracellular Al concentration and with the concentration of Al available per cell. When the concentration of phosphorus is low, internal concentrations of Al are high and the chlorophyll content and the net dry matter production per cell increase, whereas the photosynthesis and the cell division are increased. Presence of Al in a low P medium decreases the pH of the medium down to 4.5. There are only small effects of Al in the presence of P, due to precipitation of most of the Al with P in the medium.
Despite the Al-induced decrease of the pH of the culture medium, effects caused by Al cannot be explained as a pH effect. Instead, the Al effect may, at least to some extent, be related to a decrease in availability of P in the metabolism, due to formation of aluminium phosphate inside the cell. 相似文献
70.