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

In 2001, we launched the Hokkaido Study, the first prospective birth cohort study in Japan. We are currently tracking the effects of environmental chemicals, using a life course approach. The study examines life circumstances after birth, and the longest follow-up to date is 20 years of age. We have measured prenatal exposure to dioxins, organochlorine pesticides, per- and polyfluoroalkyl substances, plasticizers such as di(2-ethylhexyl) phthalate, and bisphenol A. Our findings have mostly revealed that increased exposure to these environmental chemicals is linked to increased risk of lower birth size, effects on thyroid and steroid hormones, adipokine levels, as well as disruption of neurodevelopment, including causing asthma and respiratory symptoms. However, it should be noted that our findings also include protective or null findings, which may be due to low chemical concentrations or differences in prenatal or postnatal exposure. We would like to emphasize the importance of long-term continuation of the cohort, effective utilization of the data, and application of the results to environmental and health policies.

Red adzuki beans (Vigna angularis) are primarily used in producing sweet an-paste for use in Japanese confectionery, where the quality of the an-paste is evaluated based on its purple color. Catechinopyranocyanidins A and B (cpcA and cpcB) are seed coat pigments and might be responsible for the purple color of an-paste, thus, analyzing them in an-paste is crucial. However, no quantitative analyses of these compounds in an-paste have been reported. We examined extraction conditions for cpcA and cpcB from an-paste and established a quantitative analytical method. Additionally, we developed a pre-vacuum processing procedure for preparing purple an-paste. The more purple the an-paste was, the higher the content of cpcA and cpcB extracted from it. The purple color of an-paste originated from the catechinopyranocyanidins eluted from the seed coats upon boiling. Using the proposed procedure, we prepared more intensely purple wet sarashi-an compared with that generated via a conventional procedure.

High-energy precursors can provide access to highly labile reactive intermediates, enabling unprecedented transformations under mild conditions. This review highlights a series of hypervalent λ³-haloganes, focusing on the λ³-iodanyl, λ³-bromanyl, and λ³-chloranyl groups as hypernucleofugic leaving groups. We also summarize recent studies on the generation and chemical reactivity of diatomic carbon (C₂) and m-benzyne, which can be best described as highly stabilized singlet biradicals.

The biological activity of hyaluronan (HA), a major component of the extracellular matrix in vertebrate tissues, depends on its molecular weight, and thus its degradation is a critical process for HA biological functions. Here, we review the characteristics of newly discovered proteins essential for HA degradation, hyaluronan-binding protein involved in hyaluronan depolymerization (HYBID), also known as cell migration inducing hyaluronidase 1 (CEMIP) and KIAA1199, and transmembrane protein-2 (TMEM2; alias CEMIP2). Human and mouse forms of HYBID exert their HA-degrading activity in special microenvironments including recycling endosomes. Mouse TMEM2 functions as a cell-surface hyaluronidase for HA turnover in local tissues, lymph nodes, and the liver. In contrast, the role of human TMEM2 in HA degradation is the subject of much debate. HYBID expression is upregulated by proinflammatory factors such as histamine and interleukin-6 and downregulated by transforming growth factor-β. HYBID is involved in physiological HA turnover in human skin and joint tissues and plays an important role in their pathological destruction by accelerating HA degradation.

Cell proliferation is a fundamental characteristic of organisms, driven by the holistic functions of multiple proteins encoded in the genome. However, the individual contributions of thousands of genes and the millions of protein molecules they express to cell proliferation are still not fully understood, even in simple eukaryotes. Here, we present a genome-wide translation map of cells during proliferation in the unicellular alga Cyanidioschyzon merolae, based on the sequencing of ribosome-protected messenger RNA fragments. Ribosome profiling has revealed both qualitative and quantitative changes in protein translation for each gene during cell division, driven by the large-scale reallocation of ribosomes. Comparisons of ribosome footprints from non-dividing and dividing cells allowed the identification of proteins involved in cell proliferation. Given that in vivo experiments on two selected candidate proteins identified a division-phase-specific mitochondrial nucleoid protein and a mitochondrial division protein, further analysis of the candidate proteins may offer key insights into the comprehensive mechanism that facilitate cell and organelle proliferation.

The term "clone" is commonly used in the medical and life sciences to denote a genetically identical population, at both the individual and cellular levels. The concept of clonal expansion is of fundamental importance in cancer research. The advent of advanced sequencing technologies has elucidated the clonal nature of intermediates between normal cells and cancer cells. This review underscores seminal discoveries in the blood and stratified squamous epithelial systems, emphasizing the pivotal role of mutations in DNA modifier genes and Notch pathway genes, respectively, as drivers of clonal expansion. Despite the distinct nature of these systems and their genetic backgrounds, a common biological principle emerges.

Chloroplasts are photosynthetic organelles that evolved through the endosymbiosis between cyanobacteria-like symbionts and hosts. Many studies have attempted to isolate intact chloroplasts to analyze their morphological characteristics and photosynthetic activity. Although several studies introduced isolated chloroplasts into the cells of different species, their photosynthetic activities have not been confirmed. In this study, we isolated photosynthetically active chloroplasts from the primitive red alga Cyanidioschyzon merolae and incorporated them in cultured mammalian cells via co-cultivation. The incorporated chloroplasts retained their thylakoid structure in intracellular vesicles and were maintained in the cytoplasm, surrounded by the mitochondria near the nucleus. Moreover, the incorporated chloroplasts maintained electron transport activity of photosystem II in cultured mammalian cells for at least 2 days after the incorporation. Our top-down synthetic biology-based approach may serve as a foundation for creating artificially photosynthetic animal cells.

The tremendous tidal force that is linked to the supermassive black hole (SMBH) at the center of our galaxy is expected to strongly subdue star formation in its vicinity. Stars within 1'' from the SMBH thus likely formed further from the SMBH and migrated to their current positions. In this study, spectroscopic observations of the star S0-6/S10, one of the closest (projected distance from the SMBH of ≈0''.3) late-type stars were conducted. Using metal absorption lines in the spectra of S0-6, the radial velocity of S0-6 from 2014 to 2021 was measured, and a marginal acceleration was detected, which indicated that S0-6 is close to the SMBH. The S0-6 spectra were employed to determine its stellar parameters including temperature, chemical abundances ([M/H], [Fe/H], [α/Fe], [Ca/Fe], [Mg/Fe], [Ti/Fe]), and age. As suggested by the results of this study, S0-6 is very old (≳10 Gyr) and has an origin different from that of stars born in the central pc region.

In the late 1970s, crude interferon samples were found to exhibit anti-tumour activity. This discovery led to the interferon as a "magic drug" for cancer patients. Many groups, including those in Tokyo, Zürich, and San Francisco, attempted to identify human interferon cDNAs. Tadatsugu Taniguchi was the first to announce the cloning of human interferon-β cDNA in the December 1979 issue of Proc. Jpn. Acad. Ser. B. This was followed by the cloning of human interferon-α by a Zürich group and interferon-γ by a group in Genentech in San Francisco. Recombinant interferon proteins were produced on a large scale, and interferon-α was widely used to treat C-type hepatitis patients. The biological functions of interferons were quickly elucidated with the purified recombinant interferons. The molecular mechanisms underlying virus-induced interferon gene expression were also examined using cloned chromosomal genes. The background that led to interferon gene cloning and its impact on cytokine gene hunting is described herein.