Interaction between Pheromone and Its Receptor of the Fission Yeast Schizosaccharomyces pombe Examined by a Force Spectroscopy Study

Interaction between P-factor, a peptide pheromone composed of 23 amino acid residues, and its pheromone receptor, Mam2, on the cell surface of the fission yeast Schizosaccharomyces pombe was examined by an atomic force microscope (AFM). An AFM tip was modified with P-factor derivatives to perform force curve measurements. The specific interaction force between P-factor and Mam2 was calculated to be around 120 pN at a probe speed of 1.74 μm/s. When the AFM tip was modified with truncated P-factor derivative lacking C-terminal Leu, the specific interaction between the tip and the cell surface was not observed. These results were also confirmed with an assay system using a green fluorescent protein (GFP) reporter gene to monitor the activation level of signal transduction following the interaction of Mam2 with P-factor

Interferometer design of the KAGRA gravitational wave detector

KAGRA is a cryogenic interferometric gravitational-wave detector being constructed at the underground site of Kamioka mine in Gifu prefecture, Japan. We performed an optimization of the interferomter design, to achieve the best sensitivity and a stable operation, with boundary conditions of classical noises and under various practical constraints, such as the size of the tunnel or the mirror cooling capacity. Length and alignment sensing schemes for the robust control of the interferometer are developed. In this paper, we describe the detailed design of the KAGRA interferometer as well as the reasoning behind design choices

Iodine-123 Metaiodobenzylguanidine Scintigraphic Assessment of Myocardial Sympathetic Innervation in Patients With Familial Amyloid Polyneuropathy

AbstractObjectives. This study attempted to assess myocardial sympathetic innervation using iodine-123 (I-123) metaiodobenzylguanidine (MIBG) imaging in patients with familial amyloid polyneuropathy.Background. Signs and symptoms of cardiac autonomic dysfunction are commonly seen in patients with cardiac amyloidosis. However, the incidence and magnitude of abnormalities in myocardial sympathetic nerve function by means of I-123 MIBG imaging and their relation to clinical findings, cardiac function and the results of thallium-201 (Tl-201) and technetium-99m pyrophosphate (Tc-99m PYP) myocardial scanning have not yet been clarified.Methods. We performed M-mode, two-dimensional and Doppler echocardiography and I-123 MIBG, Tl-201 and Tc-99m PYP imaging of the heart in 12 patients with familial amyloid polyneuropathy and biopsy-proved cardiac amyloidosis.Results. Ten of 12 patients had no clinical evidence of overt heart disease, but left ventricular (LV) wall thickening was observed in 4 of these 10. Left ventricular percent fractional shortening and Doppler transmitral flow velocity patterns were found to be normal in all 12 patients. Eight of 12 patients showed no myocardial MIBG accumulation, with limited uptake in the remaining 4 demonstrated only in the LV anterior wall. Diffuse but mild myocardial uptake of Tc-99m PYP occurred in only 4 of 12 patients, and all 12 had normal results on Tl-201 myocardial scanning. Complete defects on myocardial MIBG scans were found in five of eight patients with negative findings on Tc-99m PYP myocardial scanning. The incidence and magnitude of myocardial uptake of MIBG were independent of clinical findings, extent of endomyocardial amyloid deposition, electrocardiographic QRS voltage and ventricular wall thickness.Conclusions. Patients with familial amyloid polyneuropathy show a high incidence of myocardial adrenergic denervation with viable myocardium that can be identified very early in cardiac amyloidosis, before the development of clinically apparent heart disease, ventricular wall thickening, significant LV systolic and diastolic dysfunction and positive findings on Tc-99m PYP myocardial scanning.(J Am Coll Cardiol 1997;29:168–74)

Crystal structure of Saccharomyces cerevisiae mitochondrial GatFAB reveals a novel subunit assembly in tRNA-dependent amidotransferases

Yeast mitochondrial Gln-mtRNAGln is synthesized by the transamidation of mischarged Glu-mtRNAGln by a non-canonical heterotrimeric tRNA-dependent amidotransferase (AdT). The GatA and GatB subunits of the yeast AdT (GatFAB) are well conserved among bacteria and eukaryota, but the GatF subunit is a fungi-specific ortholog of the GatC subunit found in all other known heterotrimeric AdTs (GatCAB). Here we report the crystal structure of yeast mitochondrial GatFAB at 2.0 Å resolution. The C-terminal region of GatF encircles the GatA-GatB interface in the same manner as GatC, but the N-terminal extension domain (NTD) of GatF forms several additional hydrophobic and hydrophilic interactions with GatA. NTD-deletion mutants displayed growth defects, but retained the ability to respire. Truncation of the NTD in purified mutants reduced glutaminase and transamidase activities when glutamine was used as the ammonia donor, but increased transamidase activity relative to the full-length enzyme when the donor was ammonium chloride. Our structure-based functional analyses suggest the NTD is a trans-acting scaffolding peptide for the GatA glutaminase active site. The positive surface charge and novel fold of the GatF-GatA interface, shown in this first crystal structure of an organellar AdT, stand in contrast with the more conventional, negatively charged bacterial AdTs described previousl

Coronary angioplasty ameliorates hypoperfusion-induced endothelial dysfunction in patients with stable angina pectoris

Objectives.This study sought to investigate the effect of coronary angioplasty on chronic hypoperfusion-induced endothelial dysfunction in patients with coronary heart disease.Background.The endothelium is an important component for organ flow regulation. Ischemia with or without reperfusion is known to cause endothelial dysfunction. We tested the hypothesis that chronic hypoperfusion impairs endothelial function in the angiographically normal coronary artery segment distal to stenosis and that the impairment by chronic hypoperfusion is reduced by coronary angioplasty.Methods.In 13 patients with stable angina pectoris, substance P (10, 30 and 100 pmol) and nitroglycerin (200 μg) were sequentially infused into the coronary artery in a cumulative manner on the day after coronary angioplasty. In 10 of these patients, vascular responses to these agents were again investigated 3 months after angioplasty. Changes in vascular diameter were evaluated in vessels located proximal and distal to the target lesion, both of which were angiographically normal, by performing computer-assisted quantitative coronary angiography. In five patients, the transstenotic pressure gradient was also measured with a pressure sensor-mounted guide wire before angioplasty.Results.On the day after angioplasty, the magnitude of dilation by substance P in distal segments was significantly less than that in proximal segments and inversely correlated with the transstenotic pressure gradient (p < 0.05) and lesion stenosis (p < 0.05). There was no difference in nitroglycerin-induced vasodilation between the two vessel segment groups. Three months later, the impaired response to substance P in the distal segment was restored to normal.Conclusions.We conclude that chronic hypoperfusion impairs endothelium-dependent dilation of coronary artery distal to critical stenosis in patients with ischemic heart disease and that coronary angioplasty ameliorates the endothelial dysfunction within 3 months

Analysis on the cryogenic stability and mechanical properties of the LHD helical coils

Transient normal-transitions have been observed in the superconducting helical coils of LHD. Propagation of a normal-zone is analyzed with a numerical simulation code that deals with the magnetic diffusion process in a pure aluminum stabilizer. During excitation tests, a number of spike signals are observed in the balance voltage of the helical coils, which seem to be caused by mechanical disturbances. The spike signals are analyzed by applying pulse height analysis and the mechanical properties of the coil windings are investigated

葛尾村マルチメディアビレッジ事業におけるテレビ電話の受容について : 遠隔学習を中心として

平成10年度から3年間の、「葛尾村マルチメディアビレッジ事業」を研究の対象とした。公共施設や学校の他、村内全戸に配備された双方向画像伝送装置(テレビ電話)を利用する、郡山女子大学から多地点の葛尾村村民宅への遠隔学習講座や、村内小・中学校へのアメリカ人教師による英語の遠隔授業の試行状況を調査し、IT(情報通信技術)の一環としてテレビ電話の教育利用について研究を進めた。あわせてテレビ電話に対する、村民の日常生活における受容の状況を調査した。本研究の結果、郡山女子大学等から村民宅への在宅遠隔学習講座はもとより、小・中学校への遠隔授業においても、学問の雰囲気が良く伝えられ大変好評であった。画像音声双方向の機能を持つテレビ電話は、教育の場で必須の「見て話すことのできる双方向性」を満たしており、対面学習を代替えできる遠隔学習のメディアとして有望である。さらにパソコン・インターネットとの同期と非同期の相互補完システムの可能性を期待できる。一方テレビ電話の日常生活における一般的通話への受容については、現状ではやゝ時期尚早と考えられるが、子や孫、知人に会う、遠隔医療を受診するなど普通電話と競合せず、画像双方向性を活かす分野での利用から入るのが現実的であろう。A series of trials concerning personal lifelong distance learning classes and English language distance tutorials at a junior high school, using video-phones via ISDN links, were carried out between 1998-2000 in Katsurao-mura Multimedia Village. Four hundred and seventy local families, together with some of the village\u27s public institutions, had video-phone connections temporarily installed in 1998 for the purpose of experimental daily use. The trials showed that video-phone via MCU/ISDN could carry enough variety and content of academic subject matter, and offered a distance learning experience that was broadly acceptable to the users. Research from recent surveys of video-phone acceptability among users at the village indicates that they see the technology as having useful advantages in cases of special need audio-visual interactivity, including educational purposes rather than simply for ordinary communication competition in conventional telephone services . Based on this research, we propose a new binary system of distance learning comprising a synchronous component (video-phone) and an asynchronous one (the Internet)