Tokyo University of Science

About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Thin film & Enantioselective synthesis. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.

Autophagy Supports Biomass Production and Nitrogen Use Efficiency at the Vegetative Stage in Rice

Abstract: Much of the nitrogen in leaves is distributed to chloroplasts, mainly in photosynthetic proteins. During leaf senescence, chloroplastic proteins, including Rubisco, are rapidly degraded, and the released nitrogen is remobilized and reused in newly developing tissues. Autophagy facilitates the degradation of intracellular components for nutrient recycling in all eukaryotes, and recent studies have revealed critical roles for autophagy in Rubisco degradation and nitrogen remobilization into seeds in Arabidopsis (Arabidopsis thaliana). Here, we examined the function of autophagy in vegetative growth and nitrogen usage in a cereal plant, rice (Oryza sativa). An autophagy-disrupted rice mutant, Osatg7-1, showed reduced biomass production and nitrogen use efficiency compared with the wild type. While Osatg7-1 showed early visible leaf senescence, the nitrogen concentration remained high in the senescent leaves. 15N pulse chase analysis revealed suppression of nitrogen remobilization during leaf senescence in Osatg7-1. Accordingly, the reduction of nitrogen available for newly developing tissues in Osatg7-1 likely led its reduced leaf area and tillers. The limited leaf growth in Osatg7-1 decreased the photosynthetic capacity of the plant. Much of the nitrogen remaining in senescent leaves of Osatg7-1 was in soluble proteins, and the Rubisco concentration in senescing leaves of Osatg7-1 was about 2.5 times higher than in the wild type. Transmission electron micrographs showed a cytosolic fraction rich with organelles in senescent leaves of Osatg7-1. Our results suggest that autophagy contributes to efficient nitrogen remobilization at the whole-plant level by facilitating protein degradation for nitrogen recycling in senescent leaves.

Observation of current-induced bulk magnetization in elemental tellurium

Abstract: The magnetoelectric effect in bulk matter is of growing interest both fundamentally and technologically. Since the beginning of the century, the magnetoelectric effect has been studied intensively in multiferroic materials. However, magnetoelectric phenomena in materials without any (anti-)ferroic order remain almost unexplored. Here we show the observation of a new class of bulk magnetoelectric effect, by revisiting elemental trigonal tellurium. We demonstrate that elemental tellurium, which is a nonmagnetic semiconductor, exhibits current-induced magnetization. This effect is attributed to spin splitting of the bulk band owing to the lack of inversion symmetry in trigonal tellurium. This finding highlights magnetoelectricity in bulk matter driven by moving electrons without any (anti-)ferroic order. Notably, current-induced magnetization generates a magnetic field that is not circular around but is parallel to the applied current; thus, this phenomenon opens a new area of magnetic field generation beyond Ampere’s law that may lead to industrial applications. Electrical control of magnetic response in bulk material without electric or magnetic order is rare and potentially attractive for high efficient spintronics. Here, the authors report magnetization in elemental tellurium driven purely by current without any (anti-)ferroic order.

Sphingosine-1-phosphate receptor 2 is critical for follicular helper T cell retention in germinal centers.

Abstract: Follicular helper T (Tfh) cells access the B cell follicle to promote antibody responses and are particularly important for germinal center (GC) reactions. However, the molecular mechanisms of how Tfh cells are physically associated with GCs are incompletely understood. We report that the sphingosine-1-phosphate receptor 2 (S1PR2) gene is highly expressed in a subpopulation of Tfh cells that localizes in GCs. S1PR2-deficient Tfh cells exhibited reduced accumulation in GCs due to their impaired retention. T cells deficient in both S1PR2 and CXCR5 were ineffective in supporting GC responses compared with T cells deficient only in CXCR5. These results suggest that S1PR2 and CXCR5 cooperatively regulate localization of Tfh cells in GCs to support GC responses.