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51.
我国某些常见化石硅藻的环境分析 总被引:6,自引:0,他引:6
蒋辉 《Acta Botanica Sinica》1987,(4)
本文详细研究了中国海表层沉积物中的常见化石硅藻,结果表明,这些种的分布范围及数量变化随环境的不同而变化。因此,根据柱状样品中这些种类数量的变化,能够推断古气候变化,恢复古地理环境,再现海平面波动历程,进而划分、对比第四系地层。 相似文献
52.
Formation of lymphocyte colonies under serum-free culture conditions in normal individuals and patients with chronic lymphocytic leukemia 总被引:1,自引:0,他引:1
Y C Dai G Z Hu H Y Niu Z Wen Z Fang X G Lu J Li Q Wu Y P Huang R Wen 《International journal of cell cloning》1987,5(6):480-491
This paper describes a culture system which supports the formation of B cell and some T cell colonies under serum-free conditions in peripheral blood samples of normal individuals and patients with chronic lymphocytic leukemia (CLL) of B cell type. In this system, serum is replaced by bovine serum albumin, transferrin, cholesterol, insulin and catalase or horseradish peroxidase. In addition, it is necessary to add staphylococcus protein A, mitomycin-treated T cells as feeders and phytohemagglutinin leukocyte-conditioned medium as a source of growth factors. The plating efficiency is greatly enhanced when normal cells are incubated with galactose oxidase prior to plating and when CLL cells are exposed sequentially to neuraminidase and galactose oxidase. 相似文献
53.
Q. L. Zhu 《Histochemistry and cell biology》1987,86(4):385-388
Summary The detection of fibronectin (FN) in osmium-fixed and Araldite-embedded frog skin fragments was studied using a modification of Baskin's procedure (Baskin et al. 1979). Following the removal of Araldite from the semi-thin sections (0.5–1.0 m) with ethanol-NaOH solution, the sections were bleached with hydrogen peroxide. FN was detected by indirect immunoperoxidase method. For precise localization of FN, careful attention was paid to the temperature, antibody concentrations and the quality of the ethanol-NaOH solution. Our results were in agreement with those that we had obtained previously for polyethylene glycol (PEG) sections, suggesting that the present procedure is useful for the detection of FN in Araldite-embedded biological specimens. 相似文献
54.
Sequence homology in the metalloproteins; purple acid phosphatase from beef spleen and uteroferrin from porcine uterus 总被引:1,自引:0,他引:1
D F Hunt J R Yates J Shabanowitz N Z Zhu T Zirino B A Averill S T Daurat-Larroque J G Shewale R M Roberts K Brew 《Biochemical and biophysical research communications》1987,144(3):1154-1160
The primary structures of purple acid phosphatase and uteroferrin, two iron-binding glycoproteins isolated from beef spleen and porcine uterine fluids, respectively, have been examined by a combination of tandem mass spectrometry and classical Edman sequencing methods. Reported here are amino acid sequence data covering more than 90% of the primary structures for these two proteins. The sequence data reveal an unexpectedly high degree of homology, greater than 90%, for these two proteins. 相似文献
55.
Human thrombomodulin: complete cDNA sequence and chromosome localization of the gene 总被引:20,自引:0,他引:20
A human umbilical vein endothelial cell cDNA library in lambda gt11 was screened for expression of thrombomodulin antigens with affinity-purified rabbit polyclonal anti-thrombomodulin immunoglobulin G (IgG) and mouse monoclonal anti-human thrombomodulin IgG. Among 7 million recombinant clones screened, 12 were recognized by both antibodies. Two of these, lambda HTm10 and lambda HTm12, were shown to encode thrombomodulin by comparison of the amino acid sequence deduced from the nucleotide sequence to the amino acid sequence determined directly from tryptic peptides of thrombomodulin. Thrombomodulin mRNA was estimated to be 3.7 kilobases in length by Northern blot analysis of endothelial cell and placental poly(A)+ RNA. Thrombomodulin mRNA was not detected in human brain, HepG2 hepatoma cells, or the monocytic U937 cell line. Additional cDNA clones were selected by hybridization with the 1.2-kilobase insert of lambda HTm10. One isolate, lambda HTm15, contained a 3693 base pair cDNA insert with an apparent 5'-noncoding region of 146 base pairs, an open reading frame of 1725 base pairs, a stop codon, a 3'-noncoding region of 1779 base pairs, and a poly(A) tail of 40 base pairs. The cDNA sequence encodes a 60.3-kDa protein of 575 amino acids. The predicted protein sequence includes a signal peptide of approximately 21 amino acids, an amino-terminal ligand-binding domain of approximately 223 amino acids, an epidermal growth factor (EGF) homology region of 236 amino acids, a serine/threonine-rich segment of 34 amino acids, a membrane-spanning domain of 23 amino acids, and a cytoplasmic tail of 38 amino acids. The EGF-homology region consists of six tandemly repeated EGF-like domains.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
56.
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58.
Harringtonine showed cross resistance in adriamycin-resistant murine leukemia P388 (P388/ADM) and human leukemia K562 (K562/ADM) cells. The relative resistance of the P388/ADM and K562/ADM cells to harringtonine was about 7 and 40, respectively. Calcium influx blockers, diltiazem and the biscoclaurine alkaloid cepharanthine enhanced the cytotoxicity of harringtonine in P388/ADM and K562/ADM cells. The extent of enhancement was different for the two drugs, and up to a 9- to 10-fold increase in harringtonine cytotoxicity occurred in P388/ADM cells, and 14- to 22-fold enhancement in K562/ADM cells with diltiazem or cepharanthine. Harringtonine resistance of P388/ADM was circumvented completely, and the resistance of K562/ADM was circumvented partially, by diltiazem or cepharanthine. The mechanism of enhanced cytotoxicity by diltiazem and cepharanthine is probably inhibition of active efflux of harringtonine in P388/ADM and K562/ADM cells. 相似文献
59.
S. Honecker B. Bisping Zhu Yang H. -J. Rehm 《Applied microbiology and biotechnology》1989,31(1):17-24
Summary Immobilized cells of Aspergillus niger needed a lower initial sucrose concentration than free cells in order to obtain maximal yields of citric acid production. High sucrose concentrations led to reduced yields and increased polyol formation (glycerol, erythritol, arabitol). Continuous fermentation with media containing low sugar concentrations prevented the formation of polyols. The change from nitrogen-limited to phosphate-limited precultivation of immobilized spores significantly increased the productivity of the mycelium. The ratio of citric acid to residual sugar in the effluent distinctly lay in the direction of citric acid. Inside the alginate beads mainly large bulbous cells were observed. 相似文献
60.
P Favard N Favard Q L Zhu J Bourguet J P Lechaire 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,66(1-2):99-106
We have developed a technique for recovering apical membranous sheets from amphibian urinary bladders by gelatin stripping. The tissue is mounted on a lucite support and the apical surface is first stuck onto a gelatin-coated glass slide at 30 degrees C. This sandwich is then chilled on ice and the bladder is pulled away from the slide. Preliminary results indicate that this simple technique could be used to remove membranous apical sheets of various sizes, almost devoid of cytoplasmic contamination and without significant damage to the underlying cell structures. The method could also be adapted to prepare perforated cells and to study the cohesive forces between the different layers of the tissue. 相似文献