Amino acid sequence of a cytotoxin-like basic protein with low cytotoxic activity from the venom of the Thailand cobra Naja naja siamensis

AbstractA cytotoxin-like basic protein (CLBP) was isolated from the venom of the Thailand cobra (Naja naja siamensis). The cytotoxicity of CLBP toward FL cells was one order of magnitude lower than those of cytotoxins. The amino acid sequence was determined by a combination of conventional methods. The total number of amino acid residues was 62, giving a molecular mass of 6977 Da. The sequence at residues 25–30 in the CLBP molecule was found to be significantly different from those of cytotoxins. This region might play an important role in the cytotoxic activity of cytotoxins

A Study on the Characteristics of Landscape Planting of Woody Plants in Japanese Gardens

日本庭園を特色づける樹木の配植の特性について,多変量解析による定量的な検討を行った. 検討のための資料として,評価の高い庭園の実測平面図53点を用いた. 平面図から,庭園面積,樹木の投影面積,種構成,樹木本数,灌木類の植込み面積,陸地面積などを測定し,それらの処理によって12変数を作出し分析の材料とした. まず,これらの12変数を用いた主成分分析の結果,風致性の高い庭園においては,樹木類の配植は,導入される樹木の規模,樹木の本数,植被率,の3特性によってその約76%が説明されうることを示した. さらに,これらの主成分の得点を各庭園ごとに求め,その得点分布よりクラスター分析(WARD法)によって対象とした53庭園を5類型に定量分類しうることも示した. これらの類型間には,樹木配植上の明瞭な意匠のちがいが存在し,この結果を手掛りにすることによって庭園の数値設計の可能性があることを示した. また,これらの類型と庭園の造作年代との内には有意な相関性はなく,むしろ,日本庭園の多くが特定の類型に属することが示された. このことは,日本庭園の風致性や庭園造成上の特色を示す興味ある事実である

<Review>Biochemical Study on Nicotinic Acetylcholine Receptor

Nicotinic acetylcholine receptor (AChR) is a multisubunit membrane glycoprotein which functions as a ligand-triggered cation channel. Receptors from electric tissues and skeletal muscle have a molecular weight of approximately 290,000 as a monomer and are composed of four types of polypeptide chains which assemble into a heterologous α_2βγδ pentamer. We determined the carbohydrate structure of Torpedo AChR, which was the first determination for neurotransmitter receptors. About 70 % of the oligosaccharides of the AChR were of the high mannose-type, Man_9GlcNAc_2 and Man_8GlcNAc_2. These two types of oligosaccharides were distributed in all the subunits. The remaining were various kinds of complex-type oligosaccharides, existing mainly in the γ and δ subunits. The α and β subunits had only one carbohydrate chain each, while the γ and δ subunits had two and three carbohydrate chains, respectively. These glycosylation sites were identified by sequencing glycopeptides obtained by lectin-affinity chromatography. The participation of oligosaccharides in ligand-binding of AChR was examined using a newly developed binding assay. The sialic acids and high mannose-type oligosaccharides on AChR were found to be unnecessary for its ligand binding. Next we found that the β and δ subunits of Torpedo AChR were phosphorylated on their tyrosine residues. The level of the phosphorylation was enhanced by incubating the AChR-rich membrane fraction with cholinergic ligands. This suggests that cholinergic agonists physiologically regulate phosphorylation on tyrosine in vivo, which might be included in the desensitization mechanism of the receptor. We also examined the spatial relation of proteins surrounding AChR using Torpedo AChR-rich membrane fraction. Bifunctional crosslinkers revealed an intimate relation among the AChR γ subunit, 43-kD protein, and dystrophin. Finally, we found neurotoxin-binding activities in the su-pernatant fraction obtained by ultracentrifugation of a homogenate of the electric organ, which usually does not contain AChR. This new activity was different in nature from AChR, and could function as a regulator or a modulator for AChR function

A Study on the Distributional Characteristics of Rocks in Japanese Gardens

日本庭園を特色づける庭石の分布の特性について多変量解析による検討を行った. 資料としては,評価の高い庭園の実測平面図52点を用いた. 平面図から,庭園総面積と庭石の底面積および庭石の分布状態に関する8変数を抽出し,分析の材料とした. 主成分分析の結果,風致性の高いとされる庭園においては,庭石の構成が,全体の数量的規模,使用頻度の高い庭石の規模,庭石の大きさの調和性,の3特性によって約76%説明しうることが判明した. さらに,同じ8変数を用いたクラスター分析(WARD法)によって,対象とした52庭園が4類型に分類し得ることを示した. これらの類型間には,主成分分析で得た3特性の得点分布に明らかな差異があることも判明した. 分類された類型は,それぞれ特有の庭石の構成をもつが,全体としてみれば特定の類型に属する庭園が圧倒的に多いことが判明した. このことは,日本庭園の風致性ならびに造作上の特色を示す興味深い事実である