Proceedings of the Japan Academy. Series B, Physical and Biological Sciences最新文献

Neural circuits are initially created with excessive synapse formation until around birth and undergo massive reorganization until they mature. During postnatal development, necessary synapses strengthen and remain, whereas unnecessary ones are weakened and eventually eliminated. These events, collectively called "synapse elimination" or "synapse pruning", are thought to be fundamental for creating functionally mature neural circuits in adult animals. In the cerebellum of neonatal rodents, Purkinje cells (PCs) receive synaptic inputs from multiple climbing fibers (CFs). Then, inputs from a single CF are strengthened and those from the other CFs are eliminated, and most PCs become innervated by single CFs by the end of the third postnatal week. These events are regarded as a representative model of synapse elimination. This review examines the molecular and cellular mechanisms of CF synapse elimination in the developing cerebellum and argues how autism spectrum disorder (ASD)-related genes are involved in CF synapse development. We introduce recent studies to update our knowledge, incorporate new data into the known scheme, and discuss the remaining issues and future directions.

This study examined the effect of combining visual and olfactory cues to attract oriental fruit flies (OFFs). Six different colored light-emitting diodes (LEDs) served as a visual attractant and methyl eugenol served as olfactory bait to lure male flies. An internet of things (IoT)-based pest monitoring system, consisting of sensor nodes, a gateway, and automatic counting traps, was deployed in the field to automatically collect environmental data and pest counts. The results of the calibrated experiments indicated that green, yellow, or red LEDs exhibited better performance in attracting flies than white, purple, or blue LEDs or no LEDs. With an accurate combination of visual and olfactory cues, the proposed IoT-based pest monitoring system may be an effective tool in agricultural pest management, given its advantages for efficiently capturing OFFs in a labor and time saving manner, providing accurate information regarding increases in pest populations, and enabling long-term, real-time data collection.

Y. Goto and M. Kakizaki produced a rat model of non-insulin dependent diabetes mellitus (NIDDM) by repetitive selective breeding of rats with slightly impaired glucose tolerance. In contrast to most obese diabetes models, which were genetically modified animals created by inducing a gene mutation, this rat was a unique model because it was a spontaneous diabetes model created by selective breeding. Furthermore, when it became clear that this rat was a non-obese diabetic model that exhibited hyperglycemia due to a decrease in insulin secretion capacity, it was recognized as a valuable model for elucidating non-obese, hypoinsulinemic diabetes commonly seen in East Asians. Diabetes is becoming an important health problem worldwide, especially in the East Asian region, thus Goto-Kakizaki (GK) rats are becoming increasingly important as a model of non-insulin dependent diabetes mellitus.

This study summarizes current trends and future directions in projection mapping technologies. Projection mapping seamlessly merges the virtual and real worlds through projected imagery onto physical surfaces, creating an augmented reality environment. Beyond traditional applications in advertising, art, and entertainment, various fields, including medical surgery, product design, and telecommunications, have embraced projection mapping. This study categorizes recent techniques that address technical challenges in accurately replicating desired appearances on physical surfaces through projected imagery into four groups: geometric registration, radiometric compensation, defocus compensation, and shadow removal. It subsequently introduces unconventional projectors developed to resolve specific technical issues and discusses two approaches for overcoming the inherent limitations of projector hardware, such as the inability to display images floating above physical surfaces. Finally, this study concludes the discussion with possible future directions for projection mapping technologies.

Kimura's discovery of z-term in the polar motion (Astron. J. 22, 107 (1902) and Astron. Nachr. 158, 233 (1902)) was recognized as an epoch-making scientific achievement for modern Japan, opening its doors to the world in 1868. Although Kimura served as the chair of the International Latitude Service during 1922-1934 and made efforts to interpret the z-term, it was unsuccessful. The physical interpretation of the z-term was given decades later by Wako (PASJ, 22, 525 (1970)). This article highlights Kimura's additional contributions that led to the interpretation by Wako.

Nonhuman primates, particularly macaque and marmoset monkeys, serve as invaluable models for studying complex brain functions and behavior. However, the lack of suitable genetic neuromodulation tools has constrained research at the network level. This review examines the application of a chemogenetic technology, specifically, designer receptors exclusively activated by designer drugs (DREADDs), to nonhuman primates. DREADDs offer a means of reversibly controlling neuronal activity within a specific cell type or neural pathway, effectively targeting multiple brain regions simultaneously. The combination of DREADDs with imaging techniques, such as positron emission tomography and magnetic resonance imaging, has significantly enhanced nonhuman primate research, facilitating the precise visualization and manipulation of specific brain circuits and enabling the detailed monitoring of changes in network activity, which can then be correlated with altered behavior. This review outlines these technological advances and considers their potential for enhancing our understanding of primate brain circuit function and developing novel therapeutic approaches for treating brain diseases.

Regulation of membrane protein integration involves molecular devices such as Sec-translocons or the insertase YidC. We have identified an integration-promoting factor in the inner membrane of Escherichia coli called membrane protein integrase (MPIase). Structural analysis revealed that, despite its enzyme-like name, MPIase is a glycolipid with a long glycan comprising N-acetyl amino sugars, a pyrophosphate linker, and a diacylglycerol (DAG) anchor. Additionally, we found that DAG, a minor membrane component, blocks spontaneous integration. In this review, we demonstrate how they contribute to Sec-independent membrane protein integration in bacteria using a comprehensive approach including synthetic chemistry and biophysical analyses. DAG blocks unfavorable spontaneous integrations by suppressing mobility in the membrane core, whereas MPIase compensates for this. Moreover, MPIase plays critical roles in capturing a substrate protein to prevent its aggregation, attracting it to the membrane surface, facilitating its insertion into the membrane, and delivering it to other factors. The combination of DAG and MPIase efficiently regulates the integration of membrane proteins.

In 1929, Matuyama published his paper on the magnetization of mostly Quaternary volcanic rocks. In this paper, he described the results of paleomagnetic measurements of volcanic rocks from Japan and nearby areas and concluded that the latest transition of the magnetic field from reversed to normal state occurred in the early Quaternary. In the 1960s, two groups of scientists from the USA and Australia quite vigorously conducted studies of both magnetization and age of volcanic rocks. By about 1966, they completed the reversal timescale for the last 4 million years, which was to become the basis for many earth science studies. For easy reference, they suggested to call the most recent normal or reversed periods as Brunhes, Matuyama, Gauss, and Gilbert polarity epochs, with the names taken from the scientists who made very important contributions to paleomagnetism. Chron is now the official term for the epoch, and each chron is specified by a combination of a number and a character showing the polarity. However, the names of polarity epochs were already so popular that they are still quite frequently used in scientific papers. The Matuyama epoch is between 0.773 and 2.595 million years before present. Moreover, its lower limit is now used to define the start of the Quaternary.

A paper titled "On the Synthesis of Hinokitiol" appeared in this journal in 1950 and marked the beginning of a new research field of novel aromatics.

This review mainly highlights our studies on the synthesis of one-handed helical polymers with a static memory of helicity based on the noncovalent helicity induction with a helical-sense bias and subsequent memory of the helicity approach that we developed during the past decade. Apart from the previous approaches, an excess one-handed helical conformation, once induced by nonracemic molecules, is immediately retained ("memorized") after the complete removal of the nonracemic molecules, accompanied by a significant amplification of the asymmetry, providing novel switchable chiral materials for chromatographic enantioseparation and asymmetric catalysis as well as a highly sensitive colorimetric and fluorescence chiral sensor. A conceptually new one-handed helix formation in a racemic helical polymer composed of racemic repeating units through the deracemization of the pendants is described.