高必需氨基酸转基因马铃薯的研究

８０年代以来,马铃薯遗传转化系统日趋成熟,转基因工程植株已被广泛应用于基础科学研究［１］。作为食物蛋白和能量主要来源的马铃薯,提高其蛋白质含量及质量的遗传工程研究正受到人们的普遍关注［２］。Ｙａｎｇ等［２］将旨在改善氨基酸平衡的ＣＡＴ－ＨＥＡＡＥ（氯酶素乙酰转移酶－高含量人体必需氨基酸）融合基因导入马铃薯,获得了Ｓｏｕｔｈｅｒｎｂｌｏｔ、Ｎｏｒｔｈｅｒｎｂｌｏｔ、Ｗｅｓｔｅｒｎｂｌｏｔ的证据,但尚缺少氨基酸分析的资料。玉米醇溶蛋白（ｚｅｉｎ）［３］是一个富含甲硫氨酸的贮存蛋白,它和人工合成的ＨＥ…     

家兔杏仁核内钙、镁离子对电针镇痛和吗啡镇痛的拮抗作用

通过埋植套管向家兔双侧杏仁核内缓慢注射微量氯化钙或氯化镁,对电针镇痛和吗啡镇痛有显著的对抗作用。向杏仁核内注入钙离子螯合剂CDTA或钙通道抑制剂异博定则可显著加强电针镇痛和吗啡镇痛。提示:杏仁核内钙、镁离于浓度是影响吗啡镇痛和电针镇痛的重要因素,同时表明电针和吗啡镇痛的机理可能有相似之处。     

Mechanism for the increase in plasma renin activity by pentobarbital anesthesia

The mechanism by which pentobarbital anesthesia causes increases in plasma renin activity (PRA) was examined in dogs infused with either propranolol or indomethacin, an inhibitor of prostaglandin synthetase. Infusion of propranolol at 1 mg/kg, (I.V.) followed by 0.6–0.7 mg/kg/hr decreased PRA from 6.98±2.49 ng/m1/hr during control periods to 1.58±0.79 ng/m1/hr 30 minutes after the injection of propranolol (P<0.025). Subsequent induction of anesthesia with sodium pentobarbital caused PRA to rise to 3.87±0.93 ng/m1/hr in 30 minutes. (P<0.01). Plasma potassium concentration decreased from 4.6±0.2 mEq/L to reach 4.0±0.1 mEq/L 30 minutes after induction of anesthesia (P<0.005). Infusion of indomethacin at 5 mg/kg, (I.V.) followed by 1.5 ? 3.1 mg/kg/hr into conscious dogs did not decrease PRA. In contrast to the report by Montgomery et al (Fed. Proc. 36: 989, 1977), we found that the increase in PRA after pentobarbital anesthesia could not be blocked by indomethacin. PRA was 5.3±1.2 ng/m1/hr(M ± SEM) during control periods and was 4.7±1.4 ng/m1/hr 30 minutes after the infusion of indomethacin (P<0.1). PRA increased to 10.9±2.3 ng/m1/hr, 9.2±2.2 ng/m1/hr, and 7.7±1.7 ng/m1/hr at 5, 15 and 30 minutes, respectively, after the administration of pentobarbital (P<0.005, P<0.025, P<0.05). PRA declined to 4.2±1.3 ng/m1/hr 60 minutes after pentobarbital anesthesia (P<0.1). It is concluded that the mechanism by which pentobarbital causes increases in PRA is independent of prostaglandins.     

溴氰菊酯(DECIS)在茶叶中的残留降解

溴氰菊醋在田间条件下在茶树新梢上降解很缓慢,低于二氯苯醚菊酯;它在叶表的渗透力较弱。以每亩0.44—0.73克有效成份用量(合2.5%乳剂6000—10,000倍液)喷施茶树后,鲜叶中原始附着量(以鲜叶干重计)为1.34—3.23ppm。溴氰菊酯在鲜叶和成茶中的半衰期(按原始附着量计算)均为2.8天。气候条件对溴氰菊酯降解的影响较小,但如喷药后1-2天遇雨会加速溴氰菊酯残留量的降解。由于溴氰菊酯的蒸气压特低,因此鲜叶中的残留量通过加工过程的降解率很低,平均仅为29.79%。由于溴氰菊醋在水中溶解度很低,因此,成茶中的残留农药,在泡茶过程中,进入茶汤中的数量,不会超过其中含量的1%。 根据已报道的溴氰菊酯的ADI值,作者建议溴氰菊酯在成茶中的暂定允许残留标准为2ppm,茶树喷施2.5%乳剂 6000—10,000倍液时的安全间隔期为3天,这样通过茶汤进入人体的量不会超过0.02ppm。     

线性规划法在植物生态学数学模型参数估计中的应用初探

本文提出了一种植物生态学数学模型参数估计的新方法——线性规划法,并结合最小二乘法对模型参数的估计进行了实例分析。认为某种程度上前者更优于后者。是一种值得进一步研究的方法。     

Karyotypes of Pneumocystis carinii from Korean rats.

Molecular karyotyping was applied to Pneumocystis carinii(Pc) from two strains of experimental rats, Sprague Dawley(SD) and Fisher(F), in Korea. Field inversion gel electrophoresis and contour clamped homogeneous electric field electrophoresis resolved 15 chromosomal bands from the Pc. The size of the bands was estimated 270kb to 684kb from SD rats, and 273kb to 713 kb from F rats. The bands of 283 kb from SD rats and of 273 kb from F rats stained more brightly suggesting duplicated bands. Total number of chromosomes was at least 16, and total genomic size was estimated 7 x 10(6) bp. All of the bands from F rats hybridized to the probe of repeated DNA sequences of Pc and the band of 448 kb size was proved to contain rDNA sequences, but Pc. chromosome bands from SD rats showed no reactions to the probes. The 2 different karyotypes of P. carinii from 2 strains of rats were maintained consistently for 2 years.     

四种阿片受体激动剂对大鼠腹腔巨噬细胞释放过氧化氢的影响

本实验观察了四种阿片受体亚型的激动剂对大鼠腹腔巨噬细胞(Mφ)释放过氧化氢(H_2O_2的影响。吗啡、β-内啡肽和κ受体激动剂NDAP能抑制Mφ释放H_2O_2。纳洛酮能翻转吗啡和β-内啡肽的这一作用,κ受体阻断剂nor-BNI能拮抗NDAP的作用。δ受体激动剂DADLE仅在高浓度时才抑制Mφ释放H_2O_2。以上结果表明,Mφ上可能存在若干类型阿片受体,其中μ、ε和κ受体对Mφ释放H_2O_2具有明显的调节作用。     

水稻食叶类害虫等量损害系统与复合防治指标

稻纵卷叶螟Cnaphalocrocis.medinalis Guenèe中华稻蝗Oxya chinensis(Thunberg)稻苞虫Parnara guttatus (Bremer et Grey)是江苏地区水稻的主要食叶类害虫,取食水稻叶片,导致光合叶面积减少.剪叶模拟试验表明,水稻不同生育阶段叶面积损失率与产量损失率呈线性相关.其回归方程分蘖期、孕穗期、腊熟期分别为 D(I_t)=72.50759I_t^1.15906、D(I_t)=141.61737I_t^1.08002、D(I_t)=25.12434I_t^1.00569.在叶面积损失率相同的情况下,产量损失率孕穗期>分蘖期>腊熟期.试验通过三种害虫的各龄取食量,不同生育阶段水稻叶面积及为害与损失率之间的关系,建立了不同生育阶段的经济允许损害水平(EIL_t).并根据各种害虫的相对潜在取食量,计算了校正等量损害系数,为制订复合防治指标提供了依据.实践证明:以等量损害为单位的复合防治指标有较大的实用价值,生态效益、经济效益、社会效益明显.     

Coupling of proadipocyte growth arrest and differentiation. II. A cell cycle model for the physiological control of cell proliferation

Experimental evidence is presented that supports a cell cycle model showing that there are five distinct biological processes involved in proadipocyte differentiation. These include: (a) growth arrest at a distinct state in the G1 phase of the cell cycle; (b) nonterminal differentiation; (c) terminal differentiation; (d) loss of the differentiated phenotype; and (e) reinitiation of cell proliferation. Each of these events is shown to be regulated by specific human plasma components or other physiological factors. At two states designated GD and GD', coupling of growth arrest and differentiation is shown to occur. We propose that these mechanisms for the coupling of growth arrest and differentiation are physiologically significant and mimic the regulatory processes that control stem cell proliferation in vivo.