The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Presence of sterol-binding sites in the cytosol of French-bean (Phaseolus vulgaris) roots.

Vitamin D3 (cholecalciferol) and stigmasterol have been shown to stimulate Ca2+ uptake and to induce calmodulin synthesis in cultured French-bean (Phaseolus vulgaris) roots. In addition, the appearance of calmodulin in the cultures in response to vitamin D3 could be prevented by RNA-synthesis inhibitors. To investigate the possibility that the sterols affect root DNA transcription through a receptor-mediated mechanism, the existence of sterol-binding sites in P. vulgaris roots was investigated. Specific binding of [3H]vitamin D3 could be demonstrated with intact tissue and the cytosolic fraction obtained therefrom. Equilibrium in the binding reaction with cytosol was attained after 4 h of incubation at 0 degrees C. The [3H]vitamin D3 was reversibly bound, since it could be displaced by an excess of unlabelled sterol. An equilibrium binding constant ( KD) of (3.48 +/- 0.09) x 10(-9) M and a maximum binding-site concentration (nmax) of 32 +/- 2.54 (3) pmol/mg of protein could be calculated by Scatchard [(1949) Ann. N.Y. Acad. Sci. 51, 660-672] analysis. In addition to vitamin D3, stigmasterol and sitosterol were effectively able to compete with [3H]vitamin D3 for binding to root cytosol. Cortisol, oestradiol and progesterone displaced bound labelled vitamin D3 to a lesser extent, whereas 5 beta-dihydrotestosterone, lanosterol and diosgenin were ineffective. The affinity and specificity of the root sterol-binding sites are in agreement with the characteristics of tissue responses to the sterols (Ca2+ uptake and calmodulin synthesis).[1]

References

 
WikiGenes - Universities