Activation of wheat embryo calcium-regulated protein kinase by unsaturated fatty acids in the presence and absence of calcium

AbstractUnsaturated fatty acids (oleic, linoleic and arachidonic acids) markedly activate extensively purified wheat embryo Ca2+-regulated protein kinase in the absence of Ca2+ or at very low free Ca2+ levels (<0.4 μM). While oleic and linoleic acids also activate in the presence of Ca2+ (10−6−10−4 M), arachidonic acid inhibits at free Ca2+ greater than 10−5 M. Phosphatidylserine does not substantially activate in the absence of Ca2+ or the presence of high Ca2+. Stearic and arachidic acids are less effective than the unsaturated fatty acids as activators in the absence of Ca2+. This type of plant protein kinase may be regulated in vivo independently of Ca2+ through release of unsaturated fatty acids

Understanding the fate of iron in a modern temperate estuary: Leirarvogur, Iceland

Fluvial dissolved Fe concentrations decrease upon mixing with seawater, resulting in the formation of Fe-floccules. However, a clear understanding of the fate of these floccules has yet to be established. Assessing how tidal processes affect the formation of Fe-colloids in the Leirárvogur estuary, SW Iceland, is an important step in understanding the formation and potential deposition of estuarine Fe-rich minerals within this estuarine system. The Leirárvogur estuary drains predominately Fe-rich basalt, increasing the likelihood of detecting changes in Fe-phases. Fluvial waters and local lake waters that drain into the estuary were compared and the effects of seasonal changes were considered, in an attempt to understand how varying end-members and external factors play a role in Fe-rich mineral formation. Aqueous and colloidal Fe concentrations were found to be greater towards the head of the Leirárvogur estuary, suggesting that potential Fe-rich minerals and complexes are forming at sites of fluvial input. Increasing suspended colloidal Fe towards the estuary mouth suggests that Fe-colloids are readily transported seaward