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11.
The use of flow microfluorimetry in the analysis of the phenotype expression of mouse histocompatibility antigens 总被引:1,自引:0,他引:1 下载免费PDF全文
Quantitation of the expression of cell surface antigens has hitherto been limited to analysis by either cytotoxicity tests or radioimmune assays (5, 15). We report here the use of a new methodology to analyze and quantitate the expression of mouse histocompabililty antigens (H-2 locus) in hybrid clones and parental cell types. The binding of fluorescein-tagged antibody is measured on a cell-to-cell basis in large viable cell populations using flow microfluorimetric techniques. These techniques have been used to measure hapten and immunoglobulin binding to lymphocyte populations (8, 9, 14). However, this is the first report in which these techniques have been used to examine the expression of the H-2 locus. The advantage of this approach is twofold: first, a large and statistically significant sample population may be analyzed one cell at a time, thus revealing the fine detail of heterogeneity in the expression of the cell surface markers within a population. Second, as has been demonstrated for analysis of specific components of the immune system, this method does permit fluorescence-activated sorting of cell types according to their different surface populations (8, 9, 14). 相似文献
12.
Fourteen thioredoxin sequences were used to construct a minimal
phylogenetic tree by using parsimony. The bacterial thioredoxins clustered
into three groups: one containing the photosynthetic purple bacteria,
Escherichia and Corynebacterium; a second containing the photosynthetic
green bacterium, Chlorobium; and a third containing cyanobacteria. These
groupings are similar to those generated from earlier 16s RNA analyses.
Animal thioredoxins formed a fourth group. The two thioredoxins of
chloroplasts (f and m) showed contrasting phylogenetic patterns. As
predicted from prior studies, spinach chloroplast thioredoxin m grouped
with its counterparts from cyanobacteria and eukaryotic algae, but,
unexpectedly, thioredoxin f grouped with the animal thioredoxins. The
results indicate that, during evolution, thioredoxin m of contemporary
photosynthetic eukaryotic cells was derived from a prokaryotic symbiont,
whereas thioredoxin f descended from an ancestral eukaryote common to
plants and animals. The findings illustrate the potential of thioredoxin as
a phylogenetic marker and suggest a relationship between the animal and
f-type thioredoxins.
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