懒猴属的核糖体DNA变异及其种间分化关系

用１５种限制性内切酶和人２８Ｓ、１８ＳｒＤＮＡ探针构建了懒猴属各物种核糖体ＤＮＡ重复单位的限制性内切酶图谱。在进化速率较高的非转录间隔区,在大、中、小懒猴中分别定位了２３、２４、２４个酶切位点。大懒猴与中懒猴有１２个位点不同,与小懒猴有１４个位点不同,而中、小懒猴间则只有一个位点的差异。经过计算,大懒猴与中懒猴的遗传距离值为１２．６５％,与小懒猴的差异为１４．２４％,中、小懒猴间的差异则仅为０．７     

云南姬鼠的蛋白多态性及其遗传分化关系

本文采用蛋白电泳技术对来源于云南省若干地区的姬鼠属（Ａｐｏｄｅｍｕｓ）的３种姬鼠──高山姬鼠（Ａ．ｃｈｅｖｒｉｅｒｉ）８只,中华姬鼠（Ａ．ｄｒａｃｏ）３只和大耳姬鼠（Ａ．ｌａｔｒｏｎｕｍ）１只,以及作为外群的同科的绒鼠属的大绒鼠（Ｈａｐａｌｏｍｙｓｄｅｌａｌｏｒｉ）３只进行了分析。共检测遗传座位２７个,发现２１个座位存在多态性。根据蛋白多态的数据对研究对象进行遗传分化关系的探讨,用系统分析软件ＰＨＹＬＩＰ计算它们之间的分化关系,得到了一棵无根系统树。结果表明,作为外群的大绒鼠明显不同于其它３种姬鼠而聚在最外面。８只高山姬鼠个体汇聚成独立的一支,中华姬鼠的３个个体也聚成一支,但大耳姬鼠却聚在中华姬鼠一支中,因此我们认为大耳姬鼠同中华姬鼠的分化时间可能比较晚近。     

High-performance liquid chromatographic method for the determination of a novel thymidylate synthase inhibitor, AG 331, in human serum

AG 331 is a novel thymidylate synthase inhibitor currently in Phase I clinical trial. To determine the pharmacokinetic parameters of AG 331 in human subjects, a suitable analytical method was developed using high-performance liquid chromatography. Serum and urine samples were prepared using both solid-phase extraction and solvent extraction. Either 4,4′-diaminodiphenyl sulfone or benz[cd]indole-2(1H)-one were used as internal standards for the method. A reversed-phase C₁₈ analytical column completely resolved the drug and internal standard peaks from non-specific substances present in biological matrix. The method was validated for precision, accuracy, and reproducibility in serum and was linear over a concentration range of 50–2000 ng/ml, with a limit of detection of 20.0 ng/ml and a quantifiable limit of 50 ng/ml.     

地膜条件下土壤生态因子与玉米产量的关系

研究干旱地区地膜条件下,土壤生态因子对玉米产量的影响．结果表明,最佳种植模式为作物距地膜中心线２１．３—３３．２Ｃｍ,施纯Ｎ＋Ｐ为５９８—７４３ｋｇ·ｈａ－１,玉米产量为１４４９２≤Ｙ佳≤１６５９ｋｇ·ｈ－１．该种植模式有利于提高作物产量及残膜回收．     

大兴安岭林区针叶林的生长方程及火灾林木死亡率

本文用随机模拟的方法建立了北方针叶林的生长方程及其受到火灾侵害后的林木死亡率,定量地研究了火灾对这种林分变动的影响．     

在我国腹泻患儿中发现诺瓦克样病霉感染

诺瓦克病毒是引起无菌性急性胃肠炎爆发的重要病原。１９９０年１０月至１９９１年１月从河南省急性腹泻门诊患儿便样中发现了诺瓦克样病毒。经电镜观察,病毒直径约为２８ｎｍ,病毒壳似由有结构的亚单位组成,进一步用诺瓦克病毒特异的寡核苷酸引物做逆转录一聚合酶链式反应（ＲＴ－ＰＣＲ）,检定为阳性。由ＰＣＲ产物测得的核苷酸序列与诺瓦克病毒原型株相应序列比较,同源性为７２％。以上结果证实,在我国腹泻病人中有诺瓦克样病毒感染。这对我国病毒性胃肠炎流行的防治研究具有重要意义。     

家鸡和原鸡的线粒体DNA多态性比较

本文运用１１种限制性内切酶分析了家鸡（茶花鸡、尼西鸡、大理漾濞黄鸡）和原鸡共１０只个体的线粒体ＤＮＡ限制性片段长度多态性（ＲＦＬＰ）,平均每个个检测到的片段为４０条左右。但仅发现３种变异的限制性片制性格局,即ＳｔｕＩ－Ｂ,Ｅｃａ－Ｉ－ｂ和ＲＩ－Ｂ．其中ＳｔｕＩ－Ｂ和ＳｃａＩ－Ｂ为首次报道,而且均为原鸡所物有,ＥｃｏＲＩ－Ｂ则为大理漾濞黄鸡所特有。茶花鸡和尼西鸡拥有完全相同的限制性格局。经过计算,原     

笼养白腹锦鸡觅食活动的观察

笼养条件下白腹锦鸡（Ｃｈｒｙｓｏｌｏｐｈｕｓ ａｍｈｅｒｓｔｉａｅ）的日觅食活动呈现早（７：００－８：００）和晚（１８：００－１９：００）两个明显高峰期,不同季节和天气其觅食节律有一定的差异;在一年中９月翌年４月的觅食频次较高,这可能与鸟类补充繁殖期能量消耗、积累能量御寒和保证生殖腺发育有关;逐步回归分析结果表明：影响雄鸟觅食活动的主要因素为求偶、理羽和游走;影响雄鸟觅食的主要因素是游走、理羽和静     

Multiple genotypes of mitochondrial DNA within a horse population from a small region in Yunnan province of China

mtDNA genotypes of six domestic horses (three adult short horses whose heights are under 1 m and three common domestic horses) from a small region of 15 km² in Malipo county of Yunnan province of China were investigated by the technique of restriction fragment length polymorphism (RFLP) with 16 restriction endonucleases which recognize 6-bp sequences. An average of 56 fragments for an individual was obtained. Unlike other domestic animals, this population of horses exhibits high mtDNA genetic diversity. Each of the six horses has a specific mtDNA genotype showing a pattern of multiple maternal origins, as suggested by fossil and literature records. We think the population of horses is an amazing seed-resource pool of horses and hence deserves to be paid more attention from the view of conservation genetics. However, it is also remarkable that we did not find any typical mtDNA genetic markers which would discriminate between short horses and common domestic horses.     

Effect of pH on isoamylase production by Pseudomonas amyloderamosa WU 5315

The isoamylase activity of Pseudomonas amyloderamosa WU 5315 was stable over the pH range from 5.5 to 6.25 while only about 30% of the activity remained at pH 6.5. Low isoamylase activity (418 U ml^-1) was produced by the cells grown at high pH. Activity reached almost 3000 U ml^-1 when pH was kept below 6.0 during the fermentation. With 1% glucose plus 2% maltose instead of 3% maltose as carbon source, however, no pH control was required and the isoamylase activity of Ps. amyloderamosa WU 5315 increased to 3400 U ml^-1.