Since the projection of global warming emerged in 1980s with the potential of laying enormous impacts on agriculture and food security of the world, we have conducted experimental and modeling studies for clarifying its effects on rice production in Asia and for developing adaptive rice production technologies. On the basis of measurement of rice responses to climate and carbon dioxide concentration ([CO2]), the dynamic process model named SIMRIW was developed to predict global warming effects on irrigated rice. The model predicted differential regional effects of the projected global warming by doubling [CO2] on the rice yield over Asia, and indicated that high tolerance to heat-induced spikelet sterility and high yield potential under elevated [CO2] are the two important characteristics required for rice genotypes adaptive to global warming environment. Further, genetic traits associated with these characteristics and their genetic resources for breeding adaptive genotypes were identified from diverse rice germplasms. This article reviews our initiative studies in the light of the recent studies, and points out further research that is needed for better understanding and overcoming of this unprecedentedly large problem.
l-Glutamate is one of the most abundant amino acids in the body and is a constituent of proteins and a substrate in metabolism. It is well known that glutamate serves as a primary excitatory neurotransmitter and a critical neuromodulator in the brain. Recent studies have shown that in addition to its pivotal role in neural functions, glutamate plays many important roles in a variety of cellular functions, including those as intracellular and extracellular signals. In pancreatic islets, glutamate is now known to be required for the normal regulation of insulin secretion, such as incretin-induced insulin secretion. In this review, we primarily discuss the physiological and pathophysiological roles of glutamate as intracellular and extracellular signals in the functions of pancreatic islets.
Vacuolar-type ATPase (V-ATPase), initially identified in yeast and plant vacuoles, pumps protons into the lumen of organelles coupled with ATP hydrolysis. The mammalian counterpart is found ubiquitously in endomembrane organelles and the plasma membrane of specialized cells such as osteoclasts. V-ATPase is also present in unique organelles such as insulin secretory granules, neural synaptic vesicles, and acrosomes of spermatozoa. Consistent with its diverse physiological roles and unique localization, the seven subunits of V-ATPase have 2–4 isoforms that are organelle- or cell-specific. Subunits of the enzyme function in trafficking organelles and vesicles by interacting with small molecule GTPases. During osteoclast differentiation, one of the four isoforms of subunit a, a3, is indispensable for secretory lysosome trafficking to the plasma membrane. Diseases such as osteopetrosis, renal acidosis, and hearing loss are related to V-ATPase isoforms. In addition to its role as an enzyme, V-ATPase has versatile physiological roles in eukaryotic cells.
Electrons in solids constitute quantum many-body systems showing a variety of phenomena. It often happens that the eigen states of the Hamiltonian are classified into subgroups separated by energy gaps. Band structures in solids and spin polarization in Mott insulators are two representative examples. The subspace spanned by these wavefunctions belonging to each of this subgroup can be regarded as a manifold in Hilbert space, and concepts concerning differential geometry become relevant. Connection and curvature are two key quantities, which correspond to the vector potential and field strength of electromagnetism, respectively. Therefore, one can construct an effective electromagnetic field from the structure of the Hilbert space, which is called an “emergent electromagnetic field”. In this article, we review the physics related to this emergent electromagnetic field in solids, including the gauge theory of strongly correlated electrons, various Hall effects, multiferroics, topological matter, magnetic texture such as skyrmions, and the shift current in noncentrosymmetric materials.
Alzheimer’s disease (AD) is one of the major causes of chronic and progressive cognitive decline, with the pathological hallmarks of senile plaques and neurofibrillary tangles. Amyloid β peptide (Aβ) is the main component of senile plaques, and the pathological load of Aβ in the brain has been shown to be a marker of the severity of AD. To prevent the accumulation of plaques, novel and safer plant-based vaccine strategies have been suggested. In this review, we summarize the results of plant vaccines against Aβ.
The herb Ruta chalepensis L. exhibits medical effects, such as anti-inflammatory, central nervous system depressant, and antipyretic activities. However, a genetic transformation method has not yet been developed for this species. In this paper, a simple and efficient tissue culture and genetic transformation system for R. chalepensis is reported. An amyloid β-peptide (Aβ) gene, which is considered to be a causative agent of Alzheimer’s disease (AD), fused with green-fluorescent protein (GFP), was introduced into R. chalepensis. When the leaves of R. chalepensis expressing Aβ-GFP were administered orally to C57BL/6J mice, serum anti-Aβ antibody titers of several mice were elevated without the use of an adjuvant. These results indicated that an oral vaccine against AD using R. chalepensis may be feasible. R. chalepensis is rich in bioactive compounds that may have synergistic effects with the vaccine for AD. Plant-derived vaccines are safer and cheaper than those produced from animal cells or microbes, because plants can serve as biofactories at low cost and with high biosynthetic capacity.