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41.
Bovine corneal endothelial cells adhered equally well to a variety of collagens (types I, III, IV and V) consistent with a role for fibronectin in this process. They did not exhibit a preferential binding to collagen type IV—as might be anticipated if laminin were to play a significant role in their adhesion. Inhibition studies with anti-fibronectin antibodies demonstrated the importance of endogenous fibronectin in the mediation of attachment. Consistent with this, binding did not appear to require the presence of exogenous protein, since cells bound to collagens equally well in the presence or absence of added fibronectin and binding was not stimulated by pretreatment of collagens with this protein. 相似文献
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Regeneration of ventral root axons of the lumbar seventh (L7) segment into the dorsal L7 roots on the opposite side of cat spinal cord was shown by changes in the levels of acetylcholinesterase (AChE) and pseudocholinesterase (PsChE). Low levels of AChE and PsChE were found in control dorsal roots, but when regenerating ventral root fibers entered the dorsal roots, there was a doubling of AChE activity within 2 weeks. Growth appears to start some time after the first week; this is in accord with earlier evidence based on axoplasmic flow of isotope labeled protein in this experimental preparation. The level of AChE activity in the reinnervated dorsal roots increased continually for about 100 days before reaching a plateau at approximately 20 × control levels. The gradual increase and the plateau of AChE activity is in accord with a maturation of the ventral root fibers which had regenerated into the dorsal roots. PsChE in the dorsal roots changes in parallel with AChE in a ratio of 1:10, suggesting that PsChE may in part be localized in the regenerating axons. 相似文献
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A scanning electron microscopic study of selected morphological stages of Candida albicans is presented. Stages represented are budding yeast cells, mycelial-like forms, chlamydospores, germ tube formation, and an unusual rough cell type. 相似文献
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Biological production of 5-methylthioribose 总被引:2,自引:0,他引:2
H R Schroeder C J Barnes R C Bohinski M F Mallette 《Canadian journal of microbiology》1973,19(11):1347-1354
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Barnes JG 《FEBS letters》1969,2(Z1):S63-S69
The author describes a procedure developed by himself and his colleagues for obtaining estimates of the parameters of rate equations, together with information about confidence regions for the estimates. The program has been used successfully for processing results from the chemical engineering industry, with highly non-linear model systems, particularly since temperature was a variable, and the "rate constants" were non-linear combinations of other constants. In biochemical situations, in which investigations are almost always at constant temperature, the non-linearity should not be so extreme, and the procedure may well be capable of dealing with more than 5 to 7 parameters for which it is recommended. 相似文献
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Summary The plant growth retardants (2-chloroethyl)-trimethylammonium chloride (CCC) and 2-isopropyl-4-(trimethylammoniumchloride)-5-methylphenyl-piperidine-1-carboxylate (AMO-1618) inhibit gibberellic-acid biosynthesis inFusarium moniliforme at the cyclisation of geranylgeraniol to (-)-kaurene, causing an accumulation of geranylgeraniol. The two inhibitors have no effect on the biosynthesis of ergosterol inF. moniliforme or sitosterol in barley seedlings. 相似文献