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21.
Summary The effects have been analyzed of cytochalasin B and colchicine on the secretion of glycoconjugates by human bronchial expiants labeled in vitro with radioactive glucosamine. Both cytochalasin B and colchicine had no effect on baseline 14C-labeled glycoconjugate release but caused a dose-dependent (10–7–10–4 M) inhibition of 14C-glycoconjugate release and discharge of labeled macromolecules from mucous and serous cells induced by 5 · 10–5 M methacholine.Quantitative autoradiographic analyses showed that neither cytochalasin B nor colchicine inhibited 3H-threonine or 3H-glucosamine incorporation into mucous and serous cells of the submucosal glands or goblet cells of the airway epithelium. Colchicine (10–5 M) but not cytochalasin B significantly reduced the rate at which labeled macromolecules were transported through mucous, serous and goblet cells but this effect was not observed until 4 h after the addition of colchicine. Neither cytochalasin B nor colchicine affected the basal rate of labeled-macromolecule discharge from mucous, serous or goblet cells. At a concentration of 10–5 M, both agents completely inhibited the increase in labeled-macromolecule discharge induced in mucous and serous cells by methacholine.Our results suggest that in the submucosal gland of human airways microtubules and microfilaments may be important in secretagogue-induced but not in baseline cellular glycoconjugate discharge, implying that the mechanisms of the two processes differ significantly. Furthermore, a role for microtubules is suggested in the transport of secretory granules through mucous, serous and goblet cells.Supported by National Institutes of Health Research Grant 5R01HL22444. The authors gratefully acknowledge the technical assistance of Mr. Tudor Williams, Mr. Eduardo Quintanilla and Ms. Maureen Hayes 相似文献
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Results of semi-quantitative observations and quantitative sampling of seagrasses at coastal and offshore sites along the
western Arabian Gulf are presented. Overall seagrass cover (all species together) shows significant positive correlation with
latitude, but not with salinity, temperature or depth. The same pattern is shown by Halodule uninervis (Forsk.) Aschers., the dominant species. Mean seagrass biomass ranged from 53–235 g m-2 (dry weight). These values are comparable with biomass estimates from regions in which environmental conditions are generally
less extreme than in the Gulf. Seagrass biomass is significantly negatively correlated with depth and sediment grain size.
No significant correlation is apparent between seagrass biomass and factors such as season, salinity, or concentrations of
nutrients and heavy metals measured. It is pointed out that any correlations observed are not necessarily taken to imply causality. 相似文献
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Graeme D. Coles D. J. Abernethy Mary C. Christey A. J. Conner B. K. Sinclair 《Plant Molecular Biology Reporter》1991,9(1):13-20
Hairy roots, incited byAgrobacterium rhizogenes, form a useful system for analysing the expression and phenotypic effects of foreign genes in plant root tissue. Image analysis
offers a non-invasive method of describing their growth in culture. Images of pea (coarse) andBrassica (fine) hairy roots were captured, processed and analysed without difficulty using a commercially available image analysis
system. The value of this method in monitoring intermediate changes in growth pattern was illustrated by following the changes
in five putatively chlorsulfuron-resistantBrassicc hairy-root lines cultured with and without a selective level of chlorsulfuron. Areas of hairy-root research where this technique
will be particularly useful are discussed. 相似文献
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Description of two hybrids involving silver bream, Blicca bjoerkna (L.), from British waters 总被引:1,自引:0,他引:1
This paper describes specimens of naturally occurring hybrids of silver bream x bronze bream and silver bream x roach from Lincolnshire and South Humberside waters. 相似文献
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Immature Schistosoma mansoni in mice are less susceptible to antimony therapy than adult worms. KSb tartrate inhibited phosphofructokinase (PFK) (EC 2.7.1.11) to a greater extent in extracts of 3-week-old worms than adults, and inhibited production of lactate in both immature and adult worms in vitro. In vivo, KSb tartrate was accumulated similarly by 3-week-old worms and by adults: measurements of hexosephosphate following drug treatment suggested similar inhibition of PFK in the two worm stages. If antimony acts by inhibition of PFK it is not clear why the young worms are more resistant to chemotherapy than adults. 相似文献
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Corneal endothelium: a modified method for cultivation 总被引:1,自引:0,他引:1
A modified method for establishing cultures of rabbit corneal cells is described. The new technique utilized a Lucite disc in combination with a Tygon ring for growth of pure cell cultures and was compared with an explant method for growing cells. Each method provided adequate cell cultures for biochemical or ultrastructure studies of rabbit corneal cells, but the ring and disc method described here allowed the isolation of specific cell types without the interference of stromal cell contamination. 相似文献