Multidrug Sensitive Yeast Strains, Useful Tools for Chemical Genetics

The budding yeast Saccharomyces cerevisiae is a useful eukaryote model organism for application to chemical biology studies, for example, drug screening, drug evaluation, and target identification. To use yeast for chemical biology research, however, it has been necessary to construct yeast strains suitable for various compounds because of their high drug resistance. Hence, the deletion of all multidrug resistance genes except for those that are important for viability and for genetic experiments/manipulation could increase the drug sensitivity without influencing the transformation, mating, or sporulation efficiency. There are two major factors conferring multidrug resistance in S. cerevisiae: one is the drug efflux system and the other is the permeability barrier. We therefore constructed a strain which shows high sensitivity to multiple drugs by disrupting the drug efflux system using ATP-binding cassette transporters and suppressing the membrane barrier system by introducing an ERG6-inducible system. In this review, we discuss the construction of our multidrug-sensitive yeast strains and their application in chemical biology

The clinical significance of 5% change in vital capacity in patients with idiopathic pulmonary fibrosis: extended analysis of the pirfenidone trial

<p>Abstract</p> <p>Background</p> <p>Our phase III clinical trial of pirfenidone for patients with idiopathic pulmonary fibrosis (IPF) revealed the efficacy in reducing the decline of vital capacity (VC) and increasing the progression-free survival (PFS) time by pirfenidone. Recently, marginal decline in forced VC (FVC) has been reported to be associated with poor outcome in IPF. We sought to evaluate the efficacy of pirfenidone from the aspects of 5% change in VC.</p> <p>Methods</p> <p>Improvement ratings based on 5% change in absolute VC, i.e., "improved (VC ≥ 5% increase)", "stable (VC < 5% change)", and "worsened (VC ≥ 5% decrease)" at month 3, 6, 9 and 12 were compared between high-dose pirfenidone (1800 mg/day; n = 108) and placebo (n = 104) groups, and (high-dose and low-dose (1200 mg/day; n = 55)) pirfenidone (n = 163) and placebo groups. PFS times with defining the disease progression as death or a ≥ 5% decline in VC were also compared between high-dose pirfenidone and placebo groups, and low-dose pirfenidone and placebo groups. Furthermore, considering "worsened" and "non-worsened (improved and stable)" of the ratings at months 3 and 12 as "positive" and "negative", respectively, and the positive and negative predictive values of the ratings were calculated in each group.</p> <p>Results</p> <p>In the comparison of the improvement ratings, the statistically significant differences were clearly revealed at months 3, 6, 9, and 12 between pirfenidone and placebo groups. Risk reductions by pirfenidone to placebo were approximately 35% over the study period. In the comparison of the PFS times, statistically significant difference was also observed between pirfenidone and placebo groups. The positive/negative predictive values in placebo and pirfenidone groups were 86.1%/50.8% and 87.1%/71.7%, respectively. Further, the baseline characteristics of patients worsened at month 3 had generally severe impairment, and their clinical outcomes including mortality were also significantly worsened after 1 year.</p> <p>Conclusions</p> <p>The efficacy of pirfenidone in Japanese phase III trial was supported by the rating of 5% decline in VC, and the VC changes at month 3 may be used as a prognostic factor of IPF.</p> <p>Trial Registration</p> <p>This clinical trial was registered with the Japan Pharmaceutical Information Center (JAPIC) on September 13^th, 2005 (Registration Number: JAPICCTI-050121).</p

卵黄蛋白質に関する研究(第 1 報) : ウズラ卵黄蛋白質の分別について(B. 生活科学)

卵黄蛋白質の大部分は, リポイドと結合したリポ蛋白質複合体として存在している。したがって, 取り扱いが困難で, いまだ完全に分離・精製されていない。われわれは, ウズラの卵黄蛋白質を, 鶏卵の卵黄蛋白質について行なわれた方法に従って分別し, その蛋白質の諸性質を比較検討した。その結果, ウズラ卵黄成分蛋白質の混合比は, 従来分別された鶏卵黄蛋白質の場合と異なるが, 電気泳動的には大体同じ挙動を示し, 7種の蛋白質の存在を確認した。さらに, 窒素・リン含量やヒドコキシアパタイトを用いたカラムクロマトグラフィーにおいて, 鶏卵の場合と異なることを明らかにした

ヤマイモのアミラーゼに関する研究 : β-アミラーゼの精製とその性質について(B. 生活科学)

ヤマイモが生のままで食用に供することができるのは, サツマイモとは性質を異にするアミラーゼが存在するためと思われるが, その諸性状については, いまだ十分明らかにされていない。そこで, われわれは, ヤマイモのアセトンパウダーより均一な酵素を分離・精製して, その性質を検討した。その結果, 作用至適pHを4.5&acd;5.5と広範囲に持ち, 作用至適温度60℃のβ-アミラーゼであることがわかった