Expansin is a family of proteins that catalyze long-term expansion of cell walls and has been considered a principal protein that affects cell expansion in plants. We have identified the first root-specific expansin gene in soybean (Glycine max), GmEXP1, which may be responsible for root elongation. Expression levels of GmEXP1 were very high in the roots of 1-to 5-d-old seedlings, in which rapid root elongation takes place. Furthermore, GmEXP1 mRNA was most abundant in the root tip region, where cell elongation occurs, but scarce in the region of maturation, where cell elongation ceases, implying that its expression is closely related to root development processes. In situ hybridization showed that GmEXP1 transcripts were preferentially present in the epidermal cells and underlying cell layers in the root tip of the primary and secondary roots. Ectopic expression of GmEXP1 accelerated the root growth of transgenic tobacco (Nicotiana tabacum) seedlings, and the roots showed insensitivity to obstacle-touching stress. These results imply that the GmEXP1 gene plays an important role in root development in soybean, especially in the elongation and/or initiation of the primary and secondary roots.The root is a plant organ that has adapted to acquire water and nutrients from the environment (Schiefelbein et al., 1997). The root system has recently been the focus of interest as a useful system for understanding organ development because it is a relatively simple organ, its growth pattern is uniform, and it has a small number of differentiated cell types (Aeschbacher et al., 1994). Furthermore, the development of new roots (secondary or lateral roots) from an existing root (primary root) provides a novel opportunity to investigate cellular differentiation and development in plants.Although the primary and secondary roots share many basic structural features, they are different in their origin (Scheres et al., 1996). A basic feature of the root is its radial pattern, which is made up of concentric layers of tissues. Three fundamental types of the tissues are the epidermis, the cortex, and the vascular tissues (Esau, 1977;Dolan et al., 1993;Raven et al., 1999). In the longitudinal section, the root can be divided into three different regions: those of cell division, elongation, and maturation (specialization) (Dolan et al., 1993;Baluska et al., 1996;Howell, 1998;Raven et al., 1999). The region of cell division contains the root apical meristem, which carries out new cell divisions but does not elongate newly divided cells immediately. The cells derived from the region of cell division expand and elongate mostly in the region of elongation. After they have elongated, the cells begin to differentiate in the region of maturation, where root hairs and the secondary roots are initiated. The events of cell elongation and maturation occurring in the root have been suggested to be controlled by the extensibility of the cell wall and the turgor pressure inside the cell (Cosgrove, 1996).It has been proposed that development of the s...

Infrared, visible, and multispectral photodetectors are important components for sensing, security and electronics applications. Current fabrication of these devices is based on inorganic materials grown by epitaxial techniques which are not compatible with low‐cost large‐scale processing. Here, air‐stable multispectral solution‐processed inorganic double heterostructure photodetectors, using PbS quantum dots (QDs) as the photoactive layer, colloidal ZnO nanoparticles as the electron transport/hole blocking layer (ETL/HBL), and solution‐derived NiO as the hole transport/electron blocking layer (HTL/EBL) are reported. The resulting device has low dark current density of 20 nA cm‐2 with a noise equivalent power (NEP) on the order of tens of picowatts across the detection spectra and a specific detectivity (D*) value of 1.2 × 1012 cm Hz1/2 W‐1. These parameters are comparable to commercially available Si, Ge, and InGaAs photodetectors. The devices have a linear dynamic range (LDR) over 65 dB and a bandwidth over 35 kHz, which are sufficient for imaging applications. Finally, these solution‐processed inorganic devices have a long storage lifetime in air, even without encapsulation.

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Ifitm3 was previously identified as an endosomal protein that blocks viral infection 1 – 3 . Studying clinical cohorts of B-cell leukemia and lymphoma patients, we identified IFITM3 as a strong predictor of poor outcome. In normal resting B-cells, Ifitm3 was minimally expressed and mainly localized in endosomes. However, B-cell receptor (BCR) engagement induced expression of Ifitm3 and phosphorylation at Y20, resulting in accumulation at the cell surface. In B-cell leukemia, oncogenic kinases phosphorylate IFITM3-Y20, causing constitutive plasma membrane localization. Ifitm3 ˉ / ˉ naïve B-cells developed at normal numbers; however, germinal center formation and production of antigen-specific antibodies were compromised. Oncogenes that induce development of leukemia and lymphoma failed to transform Ifitm3 ˉ / ˉ B-cells. Conversely, the phospho-mimetic IFITM3-Y20E induced oncogenic PI3K-signaling and initiated transformation of pre-malignant B-cells. Mechanistic experiments revealed that Ifitm3 functions as PIP3-scaffold and central amplifier of PI3K signaling. PI3K signal-amplification depends on Ifitm3 scaffolding PIP3-accumulation via two lysine residues (K83 and K104) in its conserved intracellular loop. In Ifitm3 ˉ / ˉ B-cells, lipid rafts were depleted of PIP3, resulting in defective expression of >60 lipid raft-associated surface receptors, impaired BCR-signaling and cellular adhesion. We conclude that phosphorylation of IFITM3 upon B-cell antigen-encounter induces a dynamic switch from antiviral effector functions in endosomes to a PI3K-amplification loop at the cell surface. IFITM3-dependent amplification of PI3K-signaling in part downstream of the BCR is critical to enable rapid expansion of B-cells with high affinity to antigen. In addition, multiple oncogenes depend on IFITM3 to assemble PIP3-dependent signaling complexes and amplify PI3K-signaling for malignant transformation.