缺磷或缺铁引起白羽扇豆锰中毒的机理

白羽扇豆在缺磷或缺铁条件下均有排根形成,并且根系还原力显著增加。缺磷、缺铁根系还原力在高峰期分别高于对照。缺磷与缺铁根系还原力高峰不仅出现的时期不同,而且还原力增加部位也不一样。缺磷处理的排根区具有很高的还原力,缺铁处理还原力较高的部位是在主根和侧根的根尖以及排根区。由于Ｍｎ４＋比Ｆｅ３＋更易被还原,致使根系还原力提高促使根际大量锰被还原,这是缺磷和缺铁造成白羽扇豆锰中毒的主要原因之一。     

中药玄参的化学成分

从中药玄参（ＳｃｒｏｐｈｕｌａｒｉａｎｉｎｇｐｏｅｎｓｉｓＨｅｍｓｌ．）中分离得到１个新化合物：４－Ｏ－（对甲氧基肉桂酰基）－α－Ｌ－鼠李糖［４－Ｏ－（ｐ－ｍｅｔｈｏｘｙｃｉｎｎａｍｏｙｌ）－α－Ｌ－ｒｈａｍｎｏｐｙｒａｎｏｓｅ］;同时还分离到４个已知的环烯醚萜甙：爪钧草甙（ｈａｒｐａｇｉｄｅ）,爪钩草酯甙（ｈａｒｐａｇｏｓｉｄｅ）,Ｏ－甲基梓醇（Ｏ－ｍｅｔｈｙｌｃａｔａｌｐｏｌ）,士可玄参甙Ａ（ｓｃｒｏｐｏｌｉｏｓｉｄｅＡ）和１个已知的苯丙素甙：安格洛甙Ｃ（ａｎｇｏｒｏｓｉｄｅＣ）。新化合物的结构通过化学降解和光谱分析得到证明。     

家鸽、黄雀和黄喉鹀耳蜗核的定位与比较

向非鸣禽家鸽（Ｃｏｌｕｍｂａ ｌｉｖｉａ ｄｏｍｅｓｔｉｃｕｓ）和鸣禽黄雀（Ｃａｒｄｕｅｌｉｓ ｓｐｉｎｕｓ）、黄喉鹀（Ｅｍｂｅｒｉｚａ, ｅｌｅｇａｎｓ）耳蜗内注射 ＨＲＰ作顺行追踪表明,耳蜗纤维组成第八脑神经的听支（ Ｎ Ⅷ）后,分别投射至延髓的角状核（ＮＡ）和巨细胞核（ＮＭ）,由 ＮＡ及 ＮＭ两个亚核组成耳蜗核（ｎｕｃｌｅｕｓ ｃｏｃｈｌｅａ）,它是听觉的上行通路中的第一级中继站,延髓层状核并不接受耳蜗纤维的直接投射。家鸽与黄雀、黄喉鹀之间的ＮＡ、ＮＭ及ＮⅧ在形态和分布上都有较明显的差别。     

精子介导鱼类基因转移和聚合酶链反应检测技术

金鱼精子与美洲大绵ｗｅｉ的抗冻蛋白基因一起保温３０分钟后,再与卵子受精,共获得１４５尾成鱼和若干胚胎。从胚胎和成鱼中提取ＤＮＡ经聚合酶链反应（ＰＣＲ法）扩增和Ｓｏｕｔｈｅｒｎ ｂｌｏｔ分子杂交表明,外源的抗冻蛋白基因进入了部分受体鱼的染色体组内。测定了４５尾一年龄实验鱼中,有１２尾显示出明确的杂交带,阳性率为２６％。     

排卵,排精前后文昌鱼体内GnRH的研究

利用放射免疫分析法测定了排卵、排精前后青岛文昌鱼体内促性腺激素释放激素（ＧｎＲＨ）的含量变化,并通过高效液相色谱比较了雌、雄文昌鱼性腺及除性腺外体部ＧｎＲＨ的种类和含量的异同。结果表明：１）生殖过程中雌、雄文昌鱼体内ＧｎＲＨ含量的变化规律不同;雌性文昌鱼体内ＧｎＲＨ总含量在排卵时有所下降,排后１２小时政策最为明显,以后逐渐上升到排前水平;雄性文昌鱼仅在排精时有所下降,２小时后即稳定在排水平。２）文     

Redox conditions for stimulation of in vitro folding and assembly of the glycoprotein hormone chorionic gonadotropin

The formation of native disulfide bonds during in vitro protein folding can be limiting in obtaining biologically active proteins. Thus, optimization of redox conditions can be critical in maximizing the yield of renatured, recombinant proteins. We have employed a folding model, that of the beta subunit of human chorionic gonadotropin (hCG- beta), to investigate in vitro oxidation conditions that facilitate the folding of this protein, and have compared the in vitro rates obtained with the rate of folding that has been observed in intact cells. Two steps in the folding pathway of hCG-beta were investigated: the rate-limiting events in the folding of this protein, and the assembly of hCG-beta with, hCG-alpha. The rates of these folding events were determined with and without protein disulfide isomerase (PDI) using two different types of redox reagents: cysteamine and its oxidized equivalent, cystamine, and reduced and oxidized glutathione. Rates of the rate-limiting folding events were twofold faster in cysteamine/cystamine redox buffers than in glutathione buffers in the absence of PDI. Optimal conditions for hCG-beta folding were attained in a 2 mM glutathione buffer, pH 7.4, that contained 1 mg/mL PDI and in 10muM cysteamine/cystamine, pH 8.7, without PDI. Under these conditions, the half-time of the ratelimiting folding event was 16 to 20 min and approached the rate observed in intact cells (4 to 5 min). Moreover, folding of the beta subunit under these conditions yields a functional protein, based on its ability to assemble with the alpha subunit. The rates of assembly of hCG-beta with hCG-alpha in the cysteamine/cystamine or glutathione/PDI redox buffers were comparable (t(1/2/sb> = 9 to 12 min)). These studies show that rates of folding and assembly events that involve disulfide bond formation can be optimized by a simple buffer system composed of cysteamine and cystamine. (c) 1994 John Wiley & Sons, Inc.     

大鼠心脏血压超负荷诱导左心室HSP70基因表达

本工作应用热休克蛋白７０（ＨＳＰ７０）核酸分子杂交方法,测定了大鼠腹主动脉缩窄后左心室ＨＳＰ７０ｍＲＮＡ的水平。结果表明：大鼠腹主动脉缩窄后４ｈ,动脉血压已明显升高,并持续在高水平上;大鼠左心室重／体重比在第三天开始增加,然后持续升高,第４周时比对照组增加５９％;左心室ＨＳＰ７０ｍＲＮＡ在腹主动脉缩窄后４ｈ已明显升高,１ｄ,２ｄ,１ｗ均维持在高水平,１ｗ后逐渐消失。实验结果提示：大鼠心肌负荷增加早期,左心室ＨＳＰ７０ｍＲＮＡ表达明显增加。     

从睡眠剥夺树鼩（TBC）尿液提取内源性“睡眠因子”（sleep factor）的研究

本研究报道从睡眠剥夺（ＳＤ）４８—７２ｈ的灵长类原宗（ｐｒｉｍｉｔｉｖｅｓｔｏｃｋ）Ｔｕｐａｉａｂｅｌａｎｇｅｒｉｃｈｉｎｅｎｓｉｓ（ＴＢＣ）提取内源性“睡眠因子”（ｓｌｅｅｐｆａｃｔｏｒ）Ｓ２Ｃ和Ｓ４Ｂ。收集的尿液经超滤,清液冻干经ＳｅｐｈａｄｅｘＧ１５分离得到ＦｒａｃｔｉｏｎⅠ－Ⅴ。活性测定发现Ｆｒａｃｔｉｏｎ－Ⅲ（Ｓ２Ｃ）呈现显著δ－增强促眠效应。经ＳｅｐｈａｄｅｘＧ２５和ＳｅｐｈａｄｅｘＬＨ２０进一步净化的Ｓ４Ｂ也呈现显著δ－增强促眠效应。     

大豆蚜嗅觉在选择寄主植物中的作用

大豆蚜 Aphis hlycines 有翅和无翅孤雌生殖蚜为其寄主植物大豆叶和鼠李叶气味所引诱,而非寄主植物棉花叶和黄瓜叶气味处于中性,丝瓜叶和南瓜叶气味具有明显的排斥作用。非寄主植物气味可以遮蔽寄主植物气味的引诱作用。大豆蚜触角感受器对植物气味具有嗅觉生理反应,对一些化合物的最小感觉阈值达10-5至10-6体积比浓度,表明大豆蚜触角上存在识别植物气味的嗅觉受体细胞。由此证明,嗅觉在大豆蚜选择寄主植物过程中起重要作用。     

大豆蚜嗅觉在选择寄主植物中的作用

大豆蚜ＡＰｈｉｓｇｌｙｃｉｎｅｓ有翅和无规孤雌生殖蚜为其寄主植物大豆叶和鼠李叶气味所引诱,而非奇主植物棉花叶和黄瓜叶气味处于中性,丝瓜叶和南瓜叶气味具有明显的排斥作用。非寄主植物气味可以遮蔽寄主植物气味的引诱作用。大豆蚜触角感受器对植物气味具有嗅觉生理反应,对一些化合物的最小感觉阈值达１０－５至１０－６体积比浓度,表明大豆蚜触角上存在识别植物气味的嗅觉受体细胞。由此证明,嗅觉在大豆蚜选择寄主植物过程中起重要作用。