Phytate： impact on environment and human nutrition. A challenge for molecular breeding

Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed. Project supported by the Danish Agency for Science, Technology and Innovation, Copenhagen, Denmark and HarvestPlus     

Positioning thinking within national curriculum and assessment systems: Perspectives from Israel,New Zealand and Northern Ireland

Over the past decade there has been a major move to position ‘thinking’ (however thinking is defined and enacted) as a more explicit outcome within the curriculum of many nations, with implications for teachers’ professional development, assessment, and examination requirements. This paper analyses approaches to this challenge taken by Israel, New Zealand and Northern Ireland. Each short case study considers: the political context in which the developments emerged; the ways in which thinking has been framed within the national curriculum, assessment and examination system; and the successes and challenges of the approaches taken to embedding change. Comparing and contrasting three different national systems provides important insights into the priorities, commitments and resources allocated to supporting a focus on thinking as a valued curriculum goal and outcome. In particular, it highlights the need for greater coherence between curriculum, professional development, pedagogy and assessment policies generally. Given the increasing international emphasis on the importance of developing critical thinking and problem-solving skills as a response to 21st century learning challenges, the paper reflects on what more may need to be done to leverage and sustain change.