RECK in Neural Precursor Cells Plays a Critical Role in Mouse Forebrain Angiogenesis.

RECK in neural precursor cells (NPCs) was previously found to support Notch-dependent neurogenesis in mice. On the other hand, recent studies implicate RECK in endothelial cells (ECs) in WNT7-triggered canonical WNT signaling essential for brain angiogenesis. Here we report that RECK in NPCs is also critical for brain angiogenesis. When Reck is inactivated in Foxg1-positive NPCs, mice die shortly after birth with hemorrhage in the forebrain, with angiogenic sprouts stalling at the periphery and forming abnormal aggregates reminiscent of those in EC-selective Reck knockout mice and Wnt7a/b-deficient mice. The hemorrhage can be pharmacologically suppressed by lithium chloride. An effect of RECK in WNT7-producing cells to enhance canonical WNT-signaling in reporter cells is detectable in mixed culture but not with conditioned medium. Our findings suggest that NPC-expressed RECK has a non-cell-autonomous function to promote forebrain angiogenesis through contact-dependent enhancement of WNT signaling in ECs, implying possible involvement of RECK in neurovascular coupling.

Seasonal Variation of Plant Mineral Nutrition in Fruit Trees

Abstract This research evaluated the monthly variation of plant mineral nutrition in six species of fruit trees over a year. Leaf samples were taken from the fruit trees and nutritional status (N, P, K, Ca, Mg, Fe, Zn, Cu, Mn, and Mo) was determined in the leaves in a month basis from April until November for apple, persimmon and peach. Mandarin mineral nutrition was monitored for one year, and grape and fig from May to November. Using this data, the Diagnosis Recommendation Integrated System (DRIS) was also calculated to evaluate the nutrient balance in the plants. The concentration of N and P had seasonal differences, especially in apple and peach, which reached the peak during the summer. Apple, fig, and grape trees had large ranging on their mineral contents over the year, especially with the P and K levels reaching the minimum during the harvesting season. However, the seasonal changes in leaf micronutrient concentrations were not uniform and not affected by phenological stage. The DRIS data demonstrated that mandarin had the best nutrient balance compared to others and that K was the most limiting element among the fruit trees. In summary, the current data suggest the occurrence of a significant seasonality in mineral nutrition in these six fruit trees, especially in temperate ones.