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201.
Aechmea victoriana var discolor L. B. Foster and Aechmea dactylina Bal. are commercially propagated in vitro through lateral shoot growth. A modified Murashige and Skoog medium is used which contains both BA and IAA. These growth substances were shown in the present study to synergistically stimulate the production of ethylene by the cultured plants. The stimulation of ethylene production is correlated with the outgrowth of the lateral buds. The rise in ethylene production was concluded to induce lateral shoot growth, because: (a) outgrowth of the shoots was blocked by preventing an increase in ethylene production, (b) 1-aminocyclopropane-1-carboxylic acid (ACC), the natural precursor of ethylene biosynthesis, substituted for IAA in the promotion of ethylene production and lateral bud outgrowth. Although ACC could substitute for IAA, it could not substitute for BA; therefore, cytokinins are concluded to be essential for lateral bud outgrowth in vitro in Aechmea. These results suggest that cytokinins and ethylene both play roles in natural lateral bud initiation and that the cytokinin function involves two stages of the process. 相似文献
202.
The superoxide generating system of B cell lines. Structural homology with the phagocytic oxidase and triggering via surface Ig 总被引:11,自引:0,他引:11
F E Maly A R Cross O T Jones G Wolf-Vorbeck C Walker C A Dahinden A L De Weck 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(7):2334-2339
EBV-transformed B lymphocyte cell lines (EBV-BLCL) produce superoxide after stimulation with phorbol ester, a capacity unique among nonmyeloid cells. The superoxide producing system of EBV-BLCL (B cell oxidase) was compared with the phagocytic NADPH-oxidase and the relationship of the capacity to produce superoxide to the presence of the EBV-genome was analyzed. The two EBV-transformed B cell lines F1 and HELL generated superoxide in response to PMA (2.3 nmol/10(6) F1 cells x 1 h and 6.27 nmol/10(6) HELL cells x 1 h with 1 microgram/ml of PMA), whereas no superoxide release was detected with the EBV-positive Burkitt lymphoma line WIL-2 and the EBV-negative plasmocytoma line U-266. Also, F1 and HELL showed lucigenin-dependent chemiluminescence (CL) after PMA-treatment, whereas no CL responses were detected from WIL-2 or U-266. Further, F1 and HELL cells contained a low potential cytochrome b-245 (10.9 and 61.0 pmol/mg protein, respectively) and also a 45 kDa diphenylene-iodonium (DPI)-binding peptide, both components of the phagocytic NADPH-oxidase. In contrast, neither the cytochrome b-245 nor the 45 kDa DPI-binding peptide were detected in WIL-2 and U-266. In addition, DPI inhibited O2- production by PMA-stimulated EBV-BLCL and polymorphonuclear granulocytes. Further, F1 line cells showed superoxide dismutase-inhibitable lucigenin-dependent CL when triggered by protein A-bearing staphylococci (Cowan strain I) or by a mAb directed against human IgG in the presence of solid-phase goat anti-mouse-Ig antibody. From a panel of eight EBV-BLCL, only five responded with CL when exposed to protein A-bearing staphylococci, whereas all showed CL when treated with phorbol ester. Inasmuch as all eight EBV-BLCL possessed surface Ig and a "functional" oxidase, their differential response to cross-linking of surface Ig may be determined by differences in signal transduction. Superoxide production by EBV-BLCL appears thus related to expression of an electron transport chain structurally homologous, if not identical, with the "phagocytic" NADPH-oxidase. Apparently, the presence of EBV-genome in B cell lines does not per se lead to expression of this oxidase. This suggests that nontransformed B cells may, at a certain differentiation stage, also express a superoxide-generating chain. From the finding of stimulation of superoxide production of EBV-BLCL via surface Ig it appears possible that also Ag may be able to trigger such B cells to production of superoxide which might have an important role in the physiology of B cells. 相似文献
203.
Triggering of cytotoxic T lymphocytes and NK cells via the Tp103 pathway is dependent on the expression of the T cell receptor/CD3 complex 总被引:2,自引:0,他引:2
B Fleischer E Sturm J E De Vries H Spits 《Journal of immunology (Baltimore, Md. : 1950)》1988,141(4):1103-1107
The expression and function of the T cell activation molecule Tp103 on human cloned cytotoxic CD3+ and CD3- cells were studied. All in vitro growing CD3+ and CD3- clones expressed Tp103 regardless of their phenotype and the expression of a CD3-associated TCR complex. Whereas the CD2 pathway was functional in all these clones, only CD3-expressing clones could be triggered via Tp103 to kill target cells. In contrast, both CD2 and Tp103 pathways were suppressed after modulation of the TCR complex with anti-CD3 mAb. This indicates that the function of Tp103 but not of CD2 is dependent on the expression of a functional Ag receptor on cytotoxic T cells. Furthermore, modulation of the Ag receptor induces a state of unresponsiveness in cytotoxic T cells that cannot be attributed to just the removal of the CD3/TCR complex from the cell membrane. 相似文献
204.
J Van Damme J Van Beeumen B Decock J Van Snick M De Ley A Billiau 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(5):1534-1541
Supernatants of mitogen-stimulated human leukocytes contain two biologically related cytokines, IL-1 and hybridoma growth factor (HGF). IL-1 beta is a potent inducer of HGF in fibroblasts but has little stimulating effect on monocytes that spontaneously produce HGF. Leukocyte-derived HGF and IL-1 were separated by the use of affinity chromatography on specific antibodies and discriminating assay systems for both cytokines. They had different Mr upon gel filtration and SDS-PAGE. In contrast to IL-1 beta, HGF showed heterogeneity on a cation-exchange column. IL-1 beta and HGF were purified to homogeneity by a sequence of four and five purification steps, respectively. Leukocyte-derived HGF was characterized by analysis of its NH2-terminal amino acid sequence. This revealed complete homology with fibroblast-derived HGF, 26-kDa protein, IFN-beta 2, and B cell stimulatory factor 2, molecules which have collectively been designated as IL-6. IL-1 beta exerted an antiviral and growth-promoting effect of fibroblasts, whereas HGF/IL-6 did not. Both IL-1 and IL-6 possessed lymphocyte-activating factor activity, which could be neutralized only by an anti-serum against the corresponding cytokine. 相似文献
205.
Sensitive detection of immunogold-silver staining with darkfield and epi-polarization microscopy 总被引:3,自引:0,他引:3
M De Waele W Renmans E Segers K Jochmans B Van Camp 《The journal of histochemistry and cytochemistry》1988,36(6):679-683
We evaluated the contribution of darkfield and epi-polarization microscopy to the detection of leukocyte cell surface antigens with immunogold-silver staining (IGSS). Lymphocyte cell surface differentiation antigens were labeled with monoclonal antibodies and IGSS as described for brightfield microscopy. In darkfield and epi-polarization microscopy the labeling appeared as bright spots on a dark background. The sensitivity of detection was much higher than that of brightfield microscopy. Sixteenfold higher dilutions of the monoclonal antibody could be used to detect all cells expressing the antigen in the cell suspension. However, non-specific staining was also better visualized. The latter could be reduced to a level comparable to that of brightfield microscopy only by use of weaker labeling conditions. A 25% reduction of the silver enhancement time was necessary for this purpose. However, these weaker labeling conditions also reduced the intensity of the specific staining. Therefore, the efficiency of IGSS, as detected with darkfield and epi-polarization microscopy, was only fourfold greater than that found with brightfield microscopy or that of an immunofluorescence procedure. Especially in combination with transmitted light, to improve cell identification, epi-polarization microscopy is a reliable and sensitive method for detection of immunogold-silver-labeled cell surface antigens for diagnostic and research purposes. 相似文献
206.
207.
Farkas G. A.; Baer R. E.; Estenne M.; De Troyer A. 《Journal of applied physiology》1988,64(3):1060-1067
To examine the mechanical effects of the abdominal and triangularis sterni expiratory recruitment that occurs when anesthetized dogs are tilted head up, we measured both before and after cervical vagotomy the end-expiratory length of the costal and crural diaphragmatic segments and the end-expiratory lung volume (FRC) in eight spontaneously breathing animals during postural changes from supine (0 degree) to 80 degrees head up. Tilting the animals from 0 degree to 80 degrees head up in both conditions was associated with a gradual decrease in end-expiratory costal and crural diaphragmatic length and with a progressive increase in FRC. All these changes, however, were considerably larger (P less than 0.005 or less) postvagotomy when the expiratory muscles were no longer recruited with tilting. Alterations in the elastic properties of the lung could not account for the effects of vagotomy on the postural changes. We conclude therefore that 1) by contracting during expiration, the canine expiratory muscles minimize the shortening of the diaphragm and the increase in FRC that the action of gravity would otherwise introduce, and 2) the end-expiratory diaphragmatic length and FRC in upright dogs are thus actively determined. The present data also indicate that by relaxing at end expiration, the expiratory muscles make a substantial contribution to tidal volume in upright dogs; in the 80 degrees head-up posture, this contribution would amount to approximately 60% of tidal volume. 相似文献
208.
Anna Maria Greco Pasquale Gambardella Raffaella Sticchi Diego D'aponte Pietro De Franciscis 《Chronobiology international》1988,5(3):217-225
Circadian rhythms of serotonin (5HT), its precursors tryptophan (TP) and 5-hydroxy-tryptophan (5HTP) and its acid catabolite 5-hydroxy-indoleacetic acid (5HIAA), were determined in the hypothalamus of control rats and rats which had been treated continuously with subcutaneous imipramine (10 mg/kg/day) for 2 weeks.
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
209.
P Zeppa A Zabatta F Fulciniti A Vetrani G Di Benedetto G De Rosa L Palombini 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1988,10(5):343-348
A morphometric study was performed on 200 nuclei per case in six well-differentiated hepatocarcinomas and in six cirrhoses with cytologic atypia, using samples obtained by fine needle aspiration (FNA) biopsy of the liver. The parameters measured were the nuclear area, the nuclear perimeter and the maximum nuclear diameter. The nuclei of well-differentiated hepatocarcinomas could be distinguished from those of cirrhoses on the basis of the larger size and greater anisonucleosis of the former. A statistical analysis (using a two-sided t-test) of the means of the parameters showed significant differences between the two diagnostic groups. These results suggest that morphometric analysis can help in the differential diagnosis between well-differentiated hepatocellular carcinoma and cirrhosis with cytologic atypia in FNA biopsy samples. 相似文献
210.
D. W. Scheuermann Ch. Stilman M. H. A. De Groodt-Lasseel 《Histochemistry and cell biology》1988,88(3-6):219-225
Summary To demonstrate the intracellular store of 5-hydroxytryptamine and dopamine in pulmonary neuroepithelial bodies of the neonatal rabbit after treatment with the corresponding amino-acid precursorsl-5-hydroxytryptophan orl-3,4-dihydroxyphenylalanine, formaldehyde-induced flourescence in combination with microspectrofluorimetric analysis has been used. Emission spectra and excitation spectra in an extended wavelength range from 240 to 460 nm, the displacement of excitation peaks after exposure to hydrochloric acid vapour, and calculation of peak ratio values 410/260, 380/320, 320/260 for phenylethylamine fluorophores and 385/315 for indolylethylamine fluorphores were performed. Thus, the presence of 5-hydroxytryptamine without occurrence of 5-hydroxytryptophan was demonstrated in pulmonary neuroepithelial bodies after administration of the corresponding biological precursor, while dopamine combined with 5-hydroxytryptamine were clearly revealed after administration ofl-3,4-dihydroxyphenylalanine. The rate of photodecomposition always corroborated these findings.Dedicated to Prefessor Dr. T.H. Schiebler on the occasion of his 65th birthdaySupported by grant nr. 3.0059.81 (to D.W.S.) from the Fund for Medical Scientific Research (Belgium) 相似文献