Variation of Internal Friction with Magnetization in Nickel

The internal friction Q^ of nickel annealed at 1000℃ for 10hr was measured in a magnetic field by the electrostatic driving method. The results obtained are as follows : (1) With decreasing magnetic field H from a magnetically saturated state, Q^ increases from about H=30 Oe and shows a maximum at H=15 Oe. (2) The magnetic hysteresis loss Q^_h was separated from the whole Q^ through measurement of the dynamic stress with an interference comparameter. (3) When Q^_h is expressed as a function of magentization I/I_s, Q^_h shows a maximum at I/I_s=0.6 ; it becomes smaller with increasing driving frequency f and vanishes at f=5.8 kHz

Development of an experimental method of systematically estimating protein expression limits in HEK293 cells

Protein overexpression sometimes causes cellular defects, although the underlying mechanism is still unknown. A protein's expression limit, which triggers cellular defects, is a useful indication of the underlying mechanism. In this study, we developed an experimental method of estimating the expression limits of target proteins in the human embryonic kidney cell line HEK293 by measuring the proteins' expression levels in cells that survived after the high-copy introduction of plasmid DNA by which the proteins were expressed under a strong cytomegalovirus promoter. The expression limits of nonfluorescent target proteins were indirectly estimated by measuring the levels of green fluorescent protein (GFP) connected to the target proteins with the self-cleaving sequence P2A. The expression limit of a model GFP was similar to 5.0% of the total protein, and sustained GFP overexpression caused cell death. The expression limits of GFPs with mitochondria-targeting signals and endoplasmic reticulum localization signals were 1.6% and 0.38%, respectively. The expression limits of four proteins involved in vesicular trafficking were far lower compared to a red fluorescent protein. The protein expression limit estimation method developed will be valuable for defining toxic proteins and consequences of protein overexpression

EGassembler: online bioinformatics service for large-scale processing, clustering and assembling ESTs and genomic DNA fragments

Expressed sequence tag (EST) sequencing has proven to be an economically feasible alternative for gene discovery in species lacking a draft genome sequence. Ongoing large-scale EST sequencing projects feel the need for bioinformatics tools to facilitate uniform EST handling. This brings about a renewed importance for a universal tool for processing and functional annotation of large sets of ESTs. EGassembler () is a web server, which provides an automated as well as a user-customized analysis tool for cleaning, repeat masking, vector trimming, organelle masking, clustering and assembling of ESTs and genomic fragments. The web server is publicly available and provides the community a unique all-in-one online application web service for large-scale ESTs and genomic DNA clustering and assembling. Running on a Sun Fire 15K supercomputer, a significantly large volume of data can be processed in a short period of time. The results can be used to functionally annotate genes, to facilitate splice alignment analysis, to link the transcripts to genetic and physical maps, design microarray chips, to perform transcriptome analysis and to map to KEGG metabolic pathways. The service provides an excellent bioinformatics tool to research groups in wet-lab as well as an all-in-one-tool for sequence handling to bioinformatics researchers

A comprehensive molecular interaction map of the budding yeast cell cycle

With the accumulation of data on complex molecular machineries coordinating cell-cycle dynamics, coupled with its central function in disease patho-physiologies, it is becoming increasingly important to collate the disparate knowledge sources into a comprehensive molecular network amenable to systems-level analyses. In this work, we present a comprehensive map of the budding yeast cell-cycle, curating reactions from ∼600 original papers. Toward leveraging the map as a framework to explore the underlying network architecture, we abstract the molecular components into three planes—signaling, cell-cycle core and structural planes. The planar view together with topological analyses facilitates network-centric identification of functions and control mechanisms. Further, we perform a comparative motif analysis to identify around 194 motifs including feed-forward, mutual inhibitory and feedback mechanisms contributing to cell-cycle robustness. We envisage the open access, comprehensive cell-cycle map to open roads toward community-based deeper understanding of cell-cycle dynamics

アンジオテンシン受容体拮抗薬は、肝硬変ラットの骨格筋萎縮に対して、分岐鎖アミノ酸製剤による保護効果を増強する。

Scope: This study investigated the combined effect of the angiotensin II (AT-II) receptor blocker losartan and branched-chain amino acids (BCAAs) on skeletal muscle atrophy in rats with cirrhosis and steatohepatitis. Method and Results: Fischer 344 rats are fed a choline-deficient l-amino acid-defined (CDAA) diet for 12 weeks and treated with oral losartan (30 mg kg−1 day−1) and/or BCAAs (Aminoleban EN, 2500 mg kg−1 day−1). Treatment with losartan and BCAAs attenuated hepatic inflammation and fibrosis and improved skeletal muscle atrophy and strength in CDAA-fed rats. Both agents reduced intramuscular myostatin and pro-inflammatory cytokine levels, resulting in inhibition of the ubiquitin–proteasome system (UPS) through interference with the SMAD and nuclear factor-kappa B pathways, respectively. Losartan also augmented the BCAA-mediated increase of skeletal muscle mass by promoting insulin growth factor-I production and mitochondrial biogenesis. Moreover, losartan decreased the intramuscular expression of transcription factor EB (TFEB), a transcriptional inducer of E3 ubiquitin ligase regulated by AT-II. In vitro assays illustrated that losartan promoted mitochondrial biogenesis and reduced TFEB expression in AT-II-stimulated rat myocytes, thereby potentiating the inhibitory effects of BCAAs on the UPS and caspase-3 cleavage. Conclusion: These results indicate that this regimen could serve as a novel treatment for patients with sarcopenia and liver cirrhosis.博士（医学）・甲第861号・令和5年3月15

酢酸亜鉛とリファキシミンの併用療法による腸管バリアー機能維持によるエタノール誘発性肝線維化予防効果

BACKGROUND Hepatic overload of gut-derived lipopolysaccharide dictates the progression of alcoholic liver disease (ALD) by inducing oxidative stress and activating Kupffer cells and hepatic stellate cells through toll-like receptor 4 signaling. Therefore, targeting the maintenance of intestinal barrier integrity has attracted attention for the treatment of ALD. Zinc acetate and rifaximin, which is a nonabsorbable antibiotic, had been clinically used for patients with cirrhosis, particularly those with hepatic encephalopathy, and had been known to improve intestinal barrier dysfunction. However, only few studies focused on their efficacies in preventing the ALD-related fibrosis development. AIM To investigate the effects of a combined zinc acetate with rifaximin on liver fibrosis in a mouse ALD model. METHODS To induce ALD-related liver fibrosis, female C57BL/6J mice were fed a 2.5% (v/v) ethanol-containing Lieber-DeCarli liquid diet and received intraperitoneal carbon tetrachloride (CCl4) injection twice weekly (1 mL/kg) for 8 wk. Zinc acetate (100 mg/L) and/or rifaximin (100 mg/L) were orally administered during experimental period. Hepatic steatosis, inflammation and fibrosis as well as intestinal barrier function were evaluated by histological and molecular analyses. Moreover, the direct effects of both agents on Caco-2 barrier function were assessed by in vitro assays.RESULTSIn the ethanol plus CCl4-treated mice, combination of zinc acetate and rifaximin attenuated oxidative lipid peroxidation with downregulation of Nox2 and Nox4. This combination significantly inhibited the Kupffer cells expansion and the proinflammatory response with blunted hepatic exposure of lipopolysaccharide and the toll-like receptor 4/nuclear factor kB pathway. Consequently, liver fibrosis and hepatic stellate cells activation were efficiently suppressed with downregulation of Mmp-2, -9, -13, and Timp1. Both agents improved the atrophic changes and permeability in the ileum, with restoration of tight junction proteins (TJPs) by decreasing the expressions of tumor necrosis factor α and myosin light chain kinase. In the in vitro assay, both agents directly reinforced ethanol or lipopolysaccharide-stimulated paracellular permeability and upregulated TJPs in Caco-2 cells. CONCLUSION Dual therapy with zinc acetate and rifaximin may serve as a strategy to prevent ALD-related fibrosis by maintaining intestinal barrier integrity.博士（医学）・甲第862号・令和5年3月15