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

Catalytic antibodies possess unique features capable of both recognizing and enzymatically degrading antigens. Therefore, they are more beneficial than monoclonal antibodies (mAbs). Catalytic antibodies exhibit the ability to degrade peptides, antigenic proteins, DNA, and physiologically active molecules. However, they have a significant drawback in terms of their production. The production of a desired catalytic antibody has extensive costs, in terms of time and effort. We herein describe an evolutionary method to produce a desired catalytic antibody via conversion of a general antibody by the deletion of Pro95, which resides in complementarity-determining region-3. As over thousands of mAbs have been produced since 1975, using the novel technology discussed herein, the catalytic feature cleaving the antigen can be conferred to the mAb. In this review article, we discussed in detail not only the role of Pro95 but also the unique features of the converted catalytic antibodies. This technique will accelerate research on therapeutic application of catalytic antibodies.

The mushroom, Pleurocybella porrigens, is widely consumed in Japan; however, in autumn 2004, acute encephalopathy due to ingestion of the mushroom in a large group of patients was reported in Japan. We have continued working on the mushroom to clarify the mechanisms underlying the acute encephalopathy that occurred due to its consumption. The data collected to date have shown that three compounds, pleurocybelline (PC), a Pleurocybella porrigens lectin (PPL), and pleurocybellaziridine (PA), in the mushroom are potentially responsible for the onset of the disease; PC that exhibit lethal activity in mice and PPL formed a complex, and the complex of the two components exhibited proteolytic activity and disrupted the blood-brain barrier. Although PA was not isolated directly from the mushroom, the existence of this compound in the mushroom was predicted. The compound was chemically synthesized and its endogeneity in the mushroom was demonstrated. Furthermore, PA exhibited toxicity to oligodendrocytes.

Low molecular weight monocarboxylic acids (LMW monoacids, C₁-C₁₀) are the most abundant gaseous organic compound class in the atmosphere. Formic or acetic acid is the dominant volatile organic compound (VOC) in Earth's atmosphere. They can largely contribute to rainwater acidity, especially in the tropical forest, and react with alkaline metals, ammonia, and amines, contributing to new particle formation and secondary organic aerosol production. Gaseous and particulate LMW monoacids were abundantly reported in China. They can be directly emitted from fossil fuel combustion and biomass burring; however, the secondary formation is more important than primary emissions via the photochemical oxidation of anthropogenic and biogenic VOCs. In this paper, we review the distributions of LMW monoacids from urban, mountain, and marine sites as well as from rainwater and alpine snow samples and discuss their sources and formation mechanisms in the atmosphere. We also discuss their importance as cloud condensation nuclei (CCN) and provide future perspectives of LMW monoacids study in the warming world.

A catalog of 13,591 papers published by the Japan Academy in three phases over a century in the Proceedings of the Imperial Academy (1913-1945), the Proceedings of the Japan Academy (1945-1977), and Proceedings of the Japan Academy, divided in Series A and B (1977-2022), is made available for public access. The catalog contains information about the authors, the title of the paper, published year, volume, issue, start page, end page, the field of sciences, and the academy member who introduced the paper in the monthly academy meeting. This article reports some analyses of the catalog and discusses the trends and background of the academies' publications during the past century.

Molecular clouds (MCs) in space are the birthplace of various molecular species. Chemical reactions occurring on the cryogenic surfaces of cosmic icy dust grains have been considered to play important roles in the formation of these species. Radical reactions are crucial because they often have low barriers and thus proceed even at low temperatures such as ∼10 K. Since the 2000s, laboratory experiments conducted under low-temperature, high-vacuum conditions that mimic MC environments have revealed the elementary physicochemical processes on icy dust grains. In this review, experiments conducted by our group in this context are explored, with a focus on radical reactions on the surface of icy dust analogues, leading to the formation of astronomically abundant molecules such as H₂, H₂O, H₂CO, and CH₃OH and deuterium fractionation processes. The development of highly sensitive, non-destructive methods for detecting adsorbates and their utilization for clarifying the behavior of free radicals on ice, which contribute to the formation of complex organic molecules, are also described.

Inflammation is a host defense response to various invading stimuli, but an excessive and persistent inflammatory response can cause tissue injury, which can lead to irreversible organ damage and dysfunction. Excessive inflammatory responses are believed to link to most human diseases. A specific type of leukocyte infiltration into invaded tissues is required for inflammation. Historically, the underlying molecular mechanisms of this process during inflammation were an enigma, compromising research in the fields of inflammation, immunology, and pathology. However, the pioneering discovery of chemotactic cytokines (chemokines), monocyte-derived neutrophil chemotactic factor (MDNCF; interleukin [IL]-8, CXCL8) and monocyte chemotactic and activating factor (MCAF; monocyte chemotactic factor 1 [MCP-1], CCL2) in the late 1980s finally enabled us to address this issue. In this review, we provide a historical overview of chemokine research over the last 35 years.

The recent industrial growth has made our lives more comfortable; however, it has led to an increase in the concentration of harmful compounds, such as carbon monoxide, volatile organic compounds (e.g., toluene), and phenolic compounds (e.g., phenol and cresol), in the environment. Catalytic oxidation using environmental catalysts is an important method for the removal of harmful compounds. To date, novel environmental catalysts have been developed from unique concepts based on solid-state ionics. In particular, the oxygen supply ability of a promoter can supply active oxygen from inside the lattice to the catalytically active site. Our catalysts exhibited high activity for the oxidation of harmful chemicals under moderate conditions in both the gaseous and liquid phases compared to conventional catalysts. This short review article describes our concepts of material design and our novel catalysts (ceria-zirconia (CeO₂-ZrO₂), apatite-type lanthanum silicate (La₁₀Si₆O₂₇), and lanthanum oxyfluoride (LaOF) based catalysts).

Cohesin is a heteropentameric protein complex that contributes to various aspects of chromosome structure and function, such as sister chromatid cohesion, genome compaction, and DNA damage response. Previous studies have provided abundant information on architecture and regional structures of the cohesin complex, but the configuration and structural dynamics of the whole cohesin complex are still largely unknown, partly due to flexibility of its coiled coils. We studied cohesin organization and dynamics using in vivo functional mutation compensation. Specifically, we developed and applied genetic suppressor screening methods to identify second mutations in cohesin complex genes that rescue lethality caused by various site-specific abnormalities in the cohesin complex. Functional analysis of these missense suppressor mutations revealed novel features of cohesin. Here, we summarize recent genetic suppressor screening results and insights into: 1) cohesin's structural organization when holding chromosomal DNAs; 2) interaction between cohesin head-kleisin and hinge; 3) ATP-driven cohesin conformational changes for genome packaging.

Intravenous immunoglobulin (IVIg) has been used to treat inflammatory demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barré syndrome, and multifocal motor neuropathy. Despite studies demonstrating the clinical effectiveness of IVIg, the mechanisms underlying its effects remain to be elucidated in detail. Herein, we examined the effects of IVIg on lysolecithin-induced demyelination of the sciatic nerve in a mouse model. Mice -administered with IVIg 1 and 3 days post-injection (dpi) of lysolecithin -exhibited a significantly decreased demyelination area at 7 dpi. Immunoblotting analysis using two different preparations revealed that IVIg reacted with a 36-kDa membrane glycoprotein in the sciatic nerve. Subsequent analyses of peptide absorption identified the protein as a myelin protein in the peripheral nervous system (PNS) known as large myelin protein zero (L-MPZ). Moreover, injected IVIg penetrated the demyelinating lesion, leading to deposition on L-MPZ in the myelin debris. These results indicate that IVIg may modulate PNS demyelination, possibly by binding to L-MPZ on myelin debris.