English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The scutellar epithelial cells of rice (Oryza sativa L. cv Kimmazé) seeds actively secrete alpha-amylase in an early stage of germination. Employing an in vivo system of freshly dissected scutellar tissues, effect of Ca(2+) on the biosynthesis and the secretion of alpha-amylase have been studied. The maximum biosynthetic rate was saturated at about 0.5 mm external Ca(2+) concentrations, whereas the secretion continued to increase to concentrations above 10 mm Ca(2+). In the presence of 1 mm Ca(2+), 0.01 mum A-23187 significantly increased both the biosynthesis and the secretion of alpha-amylase.A cation-specific requirement for Ca(2+) was apparent, since both biosynthesis and extracellular secretion of alpha-amylase were inhibited by 0.1 mm EGTA but were increased above basal rate only with Ca(2+) and Sr(2+); K(+), Mg(2+), and Ba(2+) being ineffective.La(3+) and ruthenium red (selective inhibitors of [Ca(2+) + Mg(2+)]-ATPase) were found to profoundly inhibit the secretion of alpha-amylase. A calmodulin antagonist, W-7, also inhibited the secretion of alpha-amylase at concentrations where the enzyme synthesis was not much affected. Overall data indicate that Ca(2+) movement and secretion of alpha-amylase are tightly linked and it is likely that they are regulated by the cytoplasmic Ca(2+) concentration under possible control by calmodulin.

Possible Roles of Calcium and Calmodulin in the Biosynthesis and Secretion of α-Amylase in Rice Seed Scutellar Epithelium