青霉素对蓝藻细胞的作用

1967年,Biggins首次报道通过溶菌酶处理获得了有生活力的篇藻(Phormidium luridum)原生质球。此后,虽然许多作者在这方面作了不少工作,但原生质球的再生和融合问题至今没有得到解决。再生和融合与分离制备方法密切相关,因此,     

鲤鳃表面结构扫描电镜研究

鲤的鳃丝表面显示了由三边形一六边形不等的表皮细胞,呈现出各种图案式的结构。     

雄尾螨属二新种及马氏雄尾螨重新记述：（蜱螨亚纲：雄尾螨科）

作者在整理采自贵阳、长沙、武汉的马氏雄尾螨Arrenurus(Micruracarus)madarasziDaday标本中,发现了两个近似新种:拟马氏雄尾螨Arrenurus(Micruracarus)madarasziatus sp.nov.和华中雄尾螨Arrenurus(Micruracarus)huazhongensis sp.nov.本文记述了此三近以种,并作了特征鉴别。     

头端延髓腹外侧区注射5—羟色胺对应激性高血粘度...

Experiments were carried out on 62 wistar rats. The hyperviscosity and elevation of blood pressure were induced by hanging and restraining the rats with their four limbs tied on a frame. It was found that microinjection of 5-HT (25 micrograms/10 microliters) into the 4th ventricle of the brain or bilateral microinjection of 5-HT (4 micrograms/0.5 microliters/site) into rostral ventrolateral medulla (rVLM) reduced stress-induced hyperviscosity (p < 0.01) and elevation of blood pressure (p < 0.01). The effect of 5-HT injected into the 4th ventricle or rVLM was blocked by bilateral microinjection of cinanserine (4 micrograms/0.5 microliter/site) into rVLM. These results suggest that microinjection of 5-HT into 4th ventricle and rVLM could reduce stress-induced hyperviscosity and elevation of blood pressure and these effects were probably mediated via 5-HT receptors in the rVLM.     

马铃薯Y病毒外壳蛋白基因的克隆及序列分析

本文报道应用聚合酶链式反应(PCR)技术,在体外扩增马铃薯 Y 病毒外壳蛋白基因及其克隆和序列分析的结果。病毒 RNA 从马铃薯 Y 病毒感染的烟草叶片中提取,用合成的PCR 3引物及 AMV 逆转录酶合成了单链的 cDNA。利用 PCR 技术,经30个循玎的扩增。得到了一特异的0.8kb 片段。克隆后对此片段进行了限制性内切酶物理图谱分析,并测定了其全序列。实验结果证明,我们克隆到的是完整的马铃薯 Y 病毒的外壳蛋白基因。与国外报道的马铃薯 Y 病毒 N 株相比,其核苷酸序列及推测的氨基酸序列的同源率分别为97.8%和97%。将该基因导入马铃薯以期获得抗 Y 病毒马铃薯的工作正在进行。本文还对 PCR 技术用于扩增植物 RNA 病毒的方法以及用基因工程方法培育抗病毒作物新品种的可行性等进行了讨论。     

PVA和PEG预处理对大豆种子在低温吸胀过程中胚根线粒体发育和超微结构的影响

电镜观察发现,大豆种子在刚开始萌发时胚根细胞中未能见到线粒体,线粒体是在种子萌发过程中逐渐出现的,由原质体再分化发育而成。对照胚根细胞内原质体在低温吸张过程中明显膨胀,在回温后胚根细胞中原质体仍不能发育成线粒体,甚至网状膜结构破坏,呈空泡化;经聚乙烯醇(PVA)和聚乙二醇(PEG 6000)预处理的大豆种子在同样条件下线粒体能继续发育,在回温后预处理胚根细胞中线粒体发育良好,具有明显的双层膜和管状嵴的结构。这些结果表明,在低温吸胀过程中原质体能够继续再分化发育成线粒体是提高大豆种子活力和抗冷力的重要原因。     

Structure and sequence of the human α- -iduronidase gene

In humans, a deficiency of the lysosomal hydrolase α- -iduronidase (IDUA; EC 3.2.1.76) results in the lysosomal storage of the glycosaminoglycans heparan sulfate and dermatan sulfate, thereby causing the lysosomal storage disorder mucopolysaccharidosis type I. The gene for IDUA is split into 14 exons spanning approximately 19 kb. We report the sequence of two noncontiguous segments of the IDUA gene, one 1.8-kb segment containing exons 1 and 2 and surrounding sequences and a second segment of 4.5 kb containing the last 12 exons. The potential promoter for IDUA has only GC box type consensus sequences consistent with a housekeeping promoter and is bounded by an Alu repeat sequence. The first two exons of IDUA are separated by an intron of 566 bp, then there is a large intron of approximately 13 kb, and the last 12 exons are clustered within 4.5 kb. No consensus polyadenylation signal was found in the 3′ untranslated region, although two variant polyadenylation signals are proposed.     

Monoclonal Antibodies against Apple 1-Aminocyclopropane-l-Carboxylate Synthase

1-Aminocyclopropane-l-carboxylate (ACC) synthase from applefruits was purified over 5,000-fold by conventional column chromatography.By immunizing mice with this partially purified enzyme preparation,8 hybridoma lines producing monoclonal antibodies against appleACC synthase were isolated. While all 8 clones immunoprecipitatednative ACC synthase, only two clones recognized the putative(48 kDa) ACC synthase on Western blots. When a partially purifiedACC synthase preparation was incubated with S-adenosyl-L-[carboxyl-¹⁴C]methionine(AdoMet), only one radioactive protein of 48 kDa was detectedon sodium dodecyl sulfate-poly-acrylamide gel electrophoresis.This radioactive protein was specifically immunoprecipitatedby the monoclonal antibodies, indicating that apple ACC synthaseis specifically radiolabeled by its substrate AdoMet, as istomato ACC synthase. Thus, the monoclonal antibodies recognizedboth native and AdoMet-inactivated forms of ACC synthase. Whilethese antibodies failed to im-munoprecipitate ACC synthase isolatedfrom ripe tomato fruits, ripe avocado fruits or auxin-treatedmungbean hypocotyls, they were effective in immunoprecipitatingthe enzyme isolated from ripe pear fruits. (Received August 11, 1990; Accepted October 17, 1990)     

Technique for repeated collection of cerebrospinal fluid from cisterna magna of anesthetized strain 13 guinea pigs

To study biochemical changes in cerebrospinal fluid (CSF), we developed a reliable technique for repeated collection of CSF in anesthetized strain 13 guinea pigs. The animal's head was mounted in a stereotaxic instrument with ventral tilt at 30 degrees, and cisternal puncture was made with an L-shaped, 23-gauge needle through the shaved skin. Clear CSF was collected in a 1-ml syringe surrounded by crushed ice. Each collection procedure lasted for 3 min, and three consecutive collections produced about 0.2 ml of CSF. Sampling was repeated at 3-hr intervals. With intravenous saline infusion (10 ml/kg.hr), a total volume of 0.6-1.0 ml of CSF was collected over 6 to 12 hr. Animals maintained a mean blood pressure, heart rate, and minute volume, with few changes during CSF sampling for the entire collection.     

9种针阔叶幼树的蒸腾速率、叶水势与环境因子关系的研究

应用QK-1气孔仪和压力室测定了樟子松、青杨等9种针阔叶幼树的蒸腾速率与其叶水势及与环境因子的关系。采用多元线性回归和逐步回归对观测值的统计分析结果表明:在土壤供水良好的条件下,其蒸腾速率主要受气象因子的影响,与其叶水势的相关性不显著。控水试验结果表明:在水分胁迫条件下其蒸腾速率与其叶水势和土壤含水量的相关性最显著。