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1.
A fractionation procedure of mouse bone marrow cells yielding exclusively pluripotent stem cells and committed progenitors 总被引:1,自引:0,他引:1
The cell surface phenotype of pluripotent hemopoietic stem cells (CFU-S) and committed progenitors (CFU-C1, CFU-C2, BFU-E) of mouse bone marrow was analyzed with respect to their binding of wheat germ agglutinin (WGA) and two monoclonal antibodies, anti-GM-1.2 and anti-PGP-1. Stained cells were fractionated on the basis of differences in fluorescence and light scatter intensity using a light-activated cell sorter. The 6% of the cells that bound most WGA and that also had a relatively high forward light scatter (FLS) and low perpendicular light scatter (PLS) contained nearly all stem cells (CFU-S) and progenitors. Anti-GM-1.2 stained only mature myeloid cells, not CFU-S or the in vitro colony-forming cells. Anti-PGP-1 stained all bone marrow cells in varying intensities: lymphoid cells were dull, CFU-S were intermediate, CFU-C2 were brighter, and mature myeloid cells very bright. Enrichment of progenitor cells was performed by a two-step sorting procedure. First, the 6% most WGA-binding cells with high FLS and low PLS were sorted out. A 10-15-fold enrichment of progenitors and CFU-S was obtained. Next, these cells were restained with anti-GM-1.2 or anti-PGP-1 and again fractionated on the FACS. The GM-1.2-negative cells were then another four- to sevenfold more enriched for stem cells and progenitors. Of the cells in this fraction, 95% could be assigned to a colony-forming unit. With anti-PGP-1, CFU-C2 could be partly separated from more early cells such as CFU-S and BFU-E. 相似文献
2.
M van der Ploeg P van Duijn J G Bauman J E Landegent A K Raap 《Basic and applied histochemistry》1985,29(3):181-189
The study of nuclear components in cells and tissues has resulted in a wealth of information with regard to the role of chromatin in cellular processes. Here, a survey is given of procedures which allow the cytochemical investigation of nucleic acid present in microscopic preparations of cells, nuclei or metaphase chromosomes. Special attention is given to recent developments in hybridocytochemistry (in situ hybridization) which facilitate microscopic identification and localization of specific nucleotide sequences within the total amount of nucleic acids present. Some of the potentialities and limitations of these in situ hybridization methods are discussed. 相似文献
3.
Separation of spleen colony-forming units and prothymocytes by use of a monoclonal antibody detecting an H-2K determinant 总被引:1,自引:0,他引:1
A H Mulder J G Bauman J W Visser W J Boersma G J van den Engh 《Cellular immunology》1984,88(2):401-410
The density of H-2K antigens was determined on both the mouse hemopoietic stem cell, using an assay for spleen colony-forming units (CFU-S), and the prothymocyte, using a thymus repopulation assay. This was done by light-activated cell sorting of bone marrow cells labeled first with a biotinylated antibody against H-2Kk and then with avidin-fluorescein isothiocyanate. Almost all CFU-S were found to be present among the 4% bone marrow cells with high forward light scatter (FLS), low perpendicular light scatter (PLS), and bright immunofluorescence. Thymus regeneration by this brightly fluorescent fraction was delayed 3 days compared to thymus regeneration by unsorted cells, although the same number of CFU-S was present in each cell suspension. This delay indicates that differentiation from CFU-S to prothymocytes takes 3 days. The fraction of cells in the FLS/PLS window with dull anti-H-2Kk fluorescence contained few CFU-S and gave rise to a transient thymus regeneration. These findings indicate that the prothymocyte carries fewer H-2K antigens than does the CFU-S. The H-2K antigen is a marker with which CFU-S and prothymocytes can be separated. Therefore, during early T-cell differentiation, the number of H-2K molecules on the cell surface decreases (CFU-S----prothymocyte----cortical thymocyte). During maturation of T cells, a reexpression of H-2K molecules occurs, since lymph node cells and spleen cells were shown to be brightly positive for H-2K antigen. 相似文献
4.
Fatty Acids and Polar Lipids of Extremely Thermophilic Filamentous Bacterial Masses from Two Yellowstone Hot Springs 总被引:9,自引:3,他引:6 下载免费PDF全文
The fatty acid composition of filamentous bacterial masses from two very hot Yellowstone Park springs is not unusual despite the extreme environment. Both populations have a series of C(14) to C(20) straight-chain acids with a maximum at C(18), and a series of saturated iso acids with a maximum at C(17) in one case and C(19) in the other. The fatty acid pattern of this anomalous group of organisms is like that of bacteria but not of blue-green algae. Both populations have similar polar lipids and identical carotenoids. It is speculated that these organisms may be adapted to their high-temperature environment by means of stable lipoprotein membrane systems. 相似文献
5.
Fluorescent in situ hybridization allows for rapid and precise detection of specific nucleic acid sequences in interphase and metaphase cells. We applied fluorescent in situ hybridization to human lymphocyte interphase nuclei in suspension to determine differences in amounts of chromosome specific target sequences amongst individuals by dual beam flow cytometry. Biotinylated chromosome 1 and Y specific repetitive satellite DNA probes were used to measure chromosome 1 and Y polymorphism amongst eight healthy volunteers. The Y probe fluorescence was found to vary considerably in male volunteers (mean fluorescence 169, S.D. 35.6). It was also detectable in female volunteers (mean fluorescence 81, S.D. 10.7), because 5-10% of this repetitive sequence is located on autosomes. The Y probe fluorescence in males was correlated with the position of the Y chromosome cluster in bivariate flow karyotypes. When chromosome 1 polymorphism was studied, one person out of the group of eight appeared to be highly polymorphic, with a probe fluorescence 26% below the average. By means of fluorescent in situ hybridization on a glass slide and bivariate flow karyotyping, this 26% difference was found to be caused by a reduction of the centromere associated satellite DNA on one of the homologues of chromosome 1. The simultaneous hybridization to human lymphocyte interphase nuclei of biotinylated chromosome 1 specific repetitive DNA plus AAF-modified chromosome Y specific DNA was detected by triple beam flow cytometry. The bicolor double hybridized nuclei could be easily distinguished from the controls. When the sensitivity of this bicolor hybridization is improved, this approach could be useful for automatic detection of numerical chromosome aberrations, using one of the two probes as an internal control. 相似文献
6.
Summary Horseradish peroxidase (HRP) was used to study macromolecule permeation into the guinea-pig placenta perfused in situ. When tissue culture medium 199 (TC 199) was used as fetal-side perfusate, the tracer reaction product was found only lining the fetal endothelium. When a longer period of perfusion with HRP in TC 199 was used, a small amount of reaction product was found in the subendothelial space and syncytiotrophoblastic vesicles, but not in maternal lacunae. In similar experiments using a Krebs bicarbonate Ringer (KRBG) as perfusate the tracer was found (i) lining the fetal endothelium, (ii) in the lateral intercellular spaces of the endothelium, (iii) in the subendothelial space, and (iv) in the maternal lacunae.It is therefore evident that the vehicle influenced the permeability of the guinea-pig placenta to horseradish peroxidase. As other studies have shown that perfusion of the fetal side with salt solution increases pore size, the results with TC 199 are regarded as more representative of the situation in the intact animal. It is therefore suggested that the fetal endothelium of the guinea-pig placenta may be largely impermeable to molecules of the size of horseradish peroxidase (4 nm) or larger. 相似文献
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9.
A preliminary subnational statistical analysis of violence against Christians in contemporary India, this article suggests that whereas the data provide very little support for simple, demographic explanations of this violence, they do more robustly support theories emphasizing the relative status of ethnic and religious minorities (vis-à-vis majorities) and the perception, among Hindus, that Christians (and other minorities) represent a threat to their numerical, political and economic strength. 相似文献
10.
R. P. Hastings J. M. Bauman E. A. Baker K. T. Scribner 《Zeitschrift fur angewandte Ichthyologie》2013,29(6):1208-1213
Knowledge of the effects of environment and genotype on behavior during early ontogenetic stages of many fish species including lake sturgeon (Acipenser fulvescens) is generally lacking. Understanding these effects is particularly important at a time when human activities are fundamentally altering habitats and seasonal and diel physical and biotic stream features. Artificial stream channels were used in a controlled experiment to quantify lake sturgeon yolk‐sac larvae dispersal distance and stream substrate preference from different females (N = 2) whose eggs were incubated at different temperatures (10 and 18°C) that simulated stream conditions during early and late spawning and incubation periods in the Black River, Michigan. Data revealed that yolk‐sac larvae exhibited considerable variability in dispersal distance as a function of family (genotype), temperature experienced during previous (embryonic) ontogenetic stages, and environmental ‘grain’. Yolk‐sac larvae dispersal distance varied as a function of the juxtaposition of substrate to location of egg hatch. Lake sturgeon yolk‐sac larvae dispersed from mesh screens attached to bricks and settled exclusively in gravel substrate. Dispersal distance also varied as a function of family and egg incubation temperatures, reflecting differences in offspring body size and levels of endogenous yolk reserves (yolk sac area) at hatch. Expression of plasticity in dispersal behavior may be particularly important to individual survival and population levels of recruitment contingent upon the location, size, and degree of fragmentation of suitable (gravel) habitats between adult spawning and yolk‐sac larvae rearing areas. 相似文献