The Cold Box stem-loop proximal to the 5'-end of the Escherichia coli cspA gene stabilizes its mRNA at low temperature.

The 5'-end region of cspA mRNA contains a Cold Box sequence conserved among several cold-shock mRNAs. This region forms a stable stem-loop structure followed by an AU-rich sequence. Here we show that the Cold Box region is essential for the normal scale of cspA mRNA induction after cold shock because a deletion of the stem-loop significantly destabilizes the mRNA and reduces the cold shock-induced cspA mRNA amount by approximately 50%. The AU-rich track, however, slightly destabilizes the mRNA. The integrity of the stem is essential for the stabilizing function, whereas that of the loop sequence is less important. Overexpression of a mutant cspA mRNA devoid of both the AUG initiation codon and the coding sequence results in a severe growth inhibition at low temperature along with a derepression of the chromosomal cspA expression. Furthermore, the overexpressed RNA is stably associated with the 30 S and 70 S ribosomes. Our results demonstrate that the AUG initiation codon and the coding region containing the downstream box are not required for cspA mRNA to bind ribosomes and that the 5'-untranslated region by itself has a remarkable affinity to ribosomes at low temperature.     

中国黑缘蝽属新种记述(半翅目:缘蝽科)

中国黑缘蝽属(Hygia Uhler)为缘蝽科缘蝽亚科中较大的属,体均为黑色,常具黄色或褐黄色斑。截止到目前已记载19种,现由近年来采集的标本中又发现7新种,分属于两个亚属:黑缘蝽亚属Hygia Uhler及沟缘蝽亚属Colpura Bergroth,现描述如下。文内所用量度单位均为毫米。模式标本除注明者外,均存放南开大学生物系。     

Seasonal plasticity in growth and development of the speckled wood butterfly, Pararge aegeria (Satyrinae)

Regulation of growth and development by photoperiod was studied in a population of the speckled wood butterfly, Purarge aegeria L. (Lepidoptera: Satyrinae), from southern Sweden. Individuals were reared in a range of photoperiodic regimes (9L. to 22L) and temperatures (13°C to 21° C). Plasticity was found for important life-history traits- generation time, growth rate and final weight and seasonal regulation of development in response to photoperiod was found to occur at two levels. Purarge aegeria hibernates as a third instar larva or in the pupal stage, cantering one of four major developmental pathways in response to photoperiod: (1) direct development in both the larval and pupal stages, (2) pupal winter diapause with or (3) without a preceding larval summer diapause, or (4) larval winter diapause. In addition to this high-level regulation of individual development, larval growth rate and pupal development rate also appear to be finally regulated by photoperiod within each major pathway. As photoperiods decreased from 22 h to 17 h at 17° C, growth rate among directly developing larvae increased progressively, as was the case for larva? developing according to a univoltine life cycle from 17 h to 14 h. At two photoperiods, 13 h and 16 h (corresponding to shifts between major pathways), both larval and pupal development were extremely variable with the fastest individuals developing directly and the slowest developing with a diapause. This indicates a gradual nature of diapause itself, suggesting that the two level may not he fundamentally different.     

玉米螟触角电位反应的专一性

我国的玉米螟曾被记载为欧洲玉米螟(European corn borer,Ostrinia nubilalis),在研究性信息素的过程中,曾按照Klun等(1970)鉴定的欧洲玉米螟性信息素顺-和反-11-十四碳烯醇乙酸酯这两种异构体进行合成,但未发现该两种异构体的任何配比在田间有诱蛾活性。程志青等(1980)鉴定出我国玉米螟的性信息素是顺-和反-12-十四碳烯醇乙酸酯,并根据Mutuura等(1970)作的分类鉴定,认为我国的玉米螟应为亚洲玉米螟(Asiatic corn borer,Ostrinia furnacalis)。因此,近年来国内有关玉米螟的研究报告(程志青等,1980;1982;姜仲雪等,1981;任自立等,1983)都称我国的玉米螟为亚洲玉米螟。但     

Depression of Neuronal Protein Synthesis Initiation by Protein Tyrosine Kinase Inhibitors

Abstract— Growth factors stimulate cellular protein synthesis, but the intracellular signaling mechanisms that regulate initiation of mRNA translation in neurons have not been clarified. A rate-limiting step in the initiation of protein synthesis is the formation of the ternary complex among GTP, eukaryotic initiation factor 2 (elF-2), and the initiator tRNA. Here we report that genistein, a specific tyrosine kinase inhibitor, decreases tyrosine kinase activity and the content of phosphotyrosine proteins in cultured primary cortical neurons. Genistein inhibits protein synthesis by >80% in a dose-dependent manner (10–80 μg/ml) and concurrently decreases ternary complex formation by 60%. At the doses investigated, genistein depresses tyrosine kinase activity and concomitantly stimulates PKC activity. We propose that a protein tyrosine kinase participates in the initiation of protein synthesis in neurons, by affecting the activity of elF-2 directly or through a protein kinase cascade.     

血清岩藻糖测定方法学研究

本文对血清岩藻糖测定方法进行了系统研究。血清用量由200μL减至50μL,显色反应4h内稳定。吸收峰在396nm。岩藻糖浓度40μg/mL内线性良好,批间CV=2.1％。以Sephadex-G200层析,血清岩藻糖主要存在于分子量为500kD的组分中。以本法测得30例健康人血清岩藻糖浓度为588.1±172.0μmol/L。     

崖椒茎的化学成分

从崖椒（Zanthoxglum schinifolutm Sieb.et Zucc.)茎的石油醚、二氯甲烷提取物中分离得到8个化合物。经物理常数测定及光谱（UV,IR,MS,NMR)分析鉴定其为（1）白鲜碱（dictamning),（2）茵芋碱（skimmianine),(3)滨蒿内酯（scoparone),(4)崖椒内酯（schinifolin),(5)莨菪亭（scopoletin),（6）7-羟基-8-甲氧基香豆素（7-hydroxy-8-methoxycoumarin),（7）N-甲基弗林辛（N-methylflindersine),（8）β-谷甾醇（β-sitosterol),其中化合物（5）、（6）和（7）为首次从该植物中分离。