ケニヤ産植物、Psiadia punctulata に含まれる植物生長調節物質

Compounds having plant growth regulatory effect were found in Kenyan Psiadia punctulata, and two flavones,5-hydroxy-7,2',3',4',5'-pentamethoxyflavone(1) and 5,3'-dihydroxy-7,2',4',5'-tetramethoxyflavone(2) were isolated and identified as the activ constituents.植物の生長を制御する物質を広く天然に求めることは、より安全で有効な農薬およびその関連物質を開発するための重要な課題である。本研究では、レタス幼苗の生長に対する調節物質の探索をケニヤ産植物Psiadia punctulata について行った。その結果、同植物のメタノール抽出物より、5-hydroxy-7,2',3',4',5'-pentamethoxyflavone 及び　5,3'-dihydroxy-7,2',4',5'-tetramethoxyflavone を調整物質として単離した。前者は、根や胚軸の長さを130％まで増加させたが、全体の重量はほぼ80％にまで減少させた。一方、後者も同様の活性パターンを示し、根を140％伸張させ植物体重量を58％まで減少させるという興味ある現象が観察された。

Detection, epitope-mapping and function of anti-Fas autoantibody in patients with silicosis

Dysregulation of apoptosis through the Fas–Fas ligand pathway is associated with the onset of autoimmune disease. Since autoantibodies directed against unknown antigens are present in the sera of these patients, sera samples were examined for the presence of autoantibodies directed against the Fas molecule. Using Western blotting and a ProteinChip analysis, autoantibodies against Fas were detected in patients with silicosis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and weakly detected in healthy individuals. Using epitope mapping employing 12-amino-acid polypeptides with the SPOTs system, a minimum of four epitopes and a maximum of 10 epitopes were found. Several amino acid residues involved in binding FasL, such as C66, R87, L90, E93 and H126, were presented within the epitopes. Serum containing a large amount of anti-Fas autoantibody from silicosis patients inhibited the growth of a Fas-expressing human cell line, but did not inhibit the growth of a low Fas-expresser nor a Fas-expresser in which the Fas gene had been silenced by small interference RNA. All epitopes in the intracellular region of Fas were located in the death domain. The possible roles of anti-Fas autoantibody detected in healthy volunteers and patients with silicosis or autoimmune diseases are discussed here