ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Vitamin D3 and stigmasterol have been previously shown to stimulate growth, Ca2+ fluxes and calmodulin synthesis in Phaseolus vulgaris roots. In this study, these sterols (10−9M) were shown to accelerate the incorporation of [3H]-thymidine into DNA in Phaseolus vulgaris (L. cv. Contraancha) root apices, similarly to a mixture of the mitogenic plant growth factors 2,4-dichlorophenoxyacetic acid and kinetin (4.6 μM each). The effects of stigmasterol were blocked by flufenazine, a calmodulin antagonist. Analogously to stigmasterol, the plant hormones stimulated calmodulin synthesis as shown by double labeling of root proteins with [14C]-leucine and [3H]-leucine, respectively, followed by their separation on sodium dodecyl sulfate-po-lyacrylamide gels and a calmodulin affinity column, immunoblot analysis and cyclic AMP phosphodiesterase activation assays. The stimulation of root calmodulin formation by stigmasterol was abolished in the absence of Ca2+ in the incubation medium and was mimicked by the Ca2+ ionophore A–23187. The results suggest that the sterols, like plant mitogenic hormones, promote DNA synthesis, and that these compounds stimulate calmodulin synthesis as a consequence of their mitogenic activity. Ca2+ appears to mediate the action of the sterols.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1989.tb05615.x
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