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31.
Lott Timothy J.; Yang Junghui; Ye Jianhong; Wallace Douglas C. 《Bioinformatics (Oxford, England)》1985,1(4):249-252
We have developed an inexpensive yet versatile microcomputer-basedsystem for quantitating light intensity levels in autoradiographs.This system employs a standard video camera interfaced to ananalog-to-digital convertor. A program has been written forthis system which can measure intensities within a defined regionof an autoradiograph, permitting an easy and accurate quantitationof spots or bands of irregular shape.
Received on June 18, 1985; accepted on September 3, 1985 相似文献
32.
This investigation examines the immunologic basis for specific antigen-induced tube leukocyte adherence inhibition (LAI) reactivity of draining lymph node cells (LNC) from dogs with canine transmissible venereal sarcoma (CTVS). CTVS regressor LNC, macrophage-depleted LNC, and enriched T lymphocyte fractions, but not enriched B lymphocyte fractions, were specifically reactive to CTVS antigen extract in direct tube LAI. In addition, regressor LNC amplified tube LAI responses by generating supernatants with leukocyte adherence inhibition factor (LAIF) activity for normal dog indicator LNC and enriched peripheral blood mononuclear cells (PBMC) in an indirect tube LAI assay. However, macrophage-depleted LNC and enriched T lymphocyte fractions failed to generate supernatants with LAIF activity, suggesting that macrophage accessory cells play a central role in the amplification of tube LAI. Interestingly, CTVS regressor peripheral blood leukocytes (PBL) and PBMC, which were specifically reactive in direct tube LAI, also failed to generate supernatants with LAIF activity. These findings demonstrate a distinction between LAIF-mediated amplification and direct tube LAI reactivity, and suggest that leukocyte populations with differing cellular proportions and from different immunologic compartments may participate in tube LAI via different mechanisms. 相似文献
33.
A series of sequential polypeptides (LysiRj)n (R is Leu, Ser, or Gly) and random copolypeptides, (Lysx, Leuy)n, were synthesized. Their conformation in NaDodSO4 solution was determined by CD. Only (Lys-Leu)n, (Lys-Ser)n, and (Lys3-Ser)n adopt a stable β-form in the surfactant solution; (Lys-Ser2)n, (Lys-Ser3)n, (Lys2-Ser2)n, and (Lys2-Ser)n have an unstable β-form, which reverts to an unordered form in high NaDodSO4 concentrations, even though both Ser and DodSO-bound Lys+ are β-formers. In contrast, (Lys-Gly)n remains unordered in NaDodSO4 solution. On the other hand, Lys-rich (Lys2-Leu)n forms an unstable helix and (Lys2-Leu2)n a stable helix in NaDodSO4 solution. In 25 mM NaDodSO4 (Lysx, Leuy)n also forms a helix up to x = 75 and reverts to the β-form at x = 90. This compares with the helical conformation of (Lysx, Alay)n up to x = 65 and its β-form at x = 90, suggesting that Leu is an even stronger helix-former than Ala. Our results may provide a plausible explanation for the increase in helicity and disruption of the β-form for many proteins in NaDodSO4 solution, that is, the polypeptide chain of a protein usually favors a helical conformation over a β-form in the presence of excess surfactant. 相似文献
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The conformation of poly(L-ornithine) (PLO) and poly(L-lysine) (PLL) in solutions of sodium alkyl sulfates, CH3(CH2)nSO4Na with n = 7, 9, 11, 13 and 15 was studied by circular dichroism. PLO adopts a helical conformation in all 5 homologs and PLL a β-form in only 4 of the homologs. With octyl sulfate PLL has a helical conformation instead. These conformations were observed in solution of surfactants both below and above the critical micelle concentration. 相似文献
36.
A computerized calibration of the circular dichrometer 总被引:5,自引:0,他引:5
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A method for the quantitative determination of cycasin from cycad flour by gas-liquid chromatography is described. The flour is extracted with 70% ethanol and the residue from the dried extract is directly trimethylsilylated. Androsterone was found to be an excellent internal standard. The average content of cycasin from ten separate analyses of one lot of flour was . The method is rapid, sensitive, and not hindered by contaminating compounds. 相似文献
40.
Long-chain unsaturated fatty acids (UFA) having up to six double bonds are derivatized to 2-substituted 4,4-dimethyloxazolines (DMOX) and then analyzed by combined in-beam electron impact (IBEI)-B/E-linked scan mass spectrometry. This technique provides highly characteristic mass spectra and may serve as an auxiliary means for direct structure determination of individual UFA in mixtures. 相似文献