湖北安陆新的恐龙蛋类型的发现及其意义

本文记述的恐龙蛋化石标本,采自湖北省江汉盆地公安寨组下部.蛋化石保存完好.在普通光学显微镜和扫描电镜下观察,蛋壳的显微结构完整,清晰可见.根据钙质蛋壳基本结构单位的形态及排列特征,笔者建立了—新属,新种——Dendroolithus wangdianensis gen. et sp. nov.,代表恐龙蛋类一个新科——Dendroolithidae fam. nov.此外,残存的卵壳膜纤维化石的发现,将为进一步研究恐龙蛋卵壳膜的结构和氨基酸组成提供宝贵材料.     

Biochemical bases of prevention of the cytotoxic effect of xenobiotics]

Possible sources of cytotoxicity of xenobiotics and main mechanisms of realization of their damaging effect are briefly considered. Protective system of a cell is characterized with regard for the peculiarities essential for development of principles of alimentary prophylaxis of cytotoxic effects of foreign compounds. Modern approaches to alimentary modification of the processes of biotransformation of xenobiotics and promotion of protective capacities of a cell are discussed.     

NMDA受体在海马CA_3区习得性LTP保持中的作用

在大鼠明暗分辨学习的建立和巩固过程中,通过与记录电极一起慢性埋植于海马CA_3区的注药管微量注射NMDA受体的特异性拮抗剂2-amino-5-phosphonovaleric acid(APV),观察对海马CA_3区突触效应及与之相关的习得性行为的影响。结果如下:(1)在动物经训练PS峰幅值刚增大至最高水平后,即在习得性LTP刚好形成后,每实验单元先于CA_3区注射AFV 1μl(2mmol/L),然后在药物有效作用时间内再进行训练,则PS峰值不能随训练而保持在最高水平,相反经8个实验单元,PS峰值降至实验前水平;相应地动物的正确反应率不能随训练而巩固,反而下降至10％以下。(2)在动物习得性LTP已形成并经一单元训练PS保持在最高水平后,于每实验单元训练前注射APV 1μl(2mmol/L),PS峰值同样不会随训练而保持在最高水平,经14个实验单元注药和训练,PS峰值逐渐降至实验前水平,相应地动物行为的正确反应率也降至10％以下,习得性行为消退,不过其消退速度比前一情况的动物为慢,说明习得性LTP发展情况不同,APV的作用效率有差别。结果表明:NMDA受体在习得性LTP的巩固中起着重要作用。     

Background impulse activity of neurons of the fastigial nucleus in the rat cerebellum

Background impulse activity (BIA) of neuronal elements of the fastigial nucleus (FN) of rat cerebellum were investigated for the first time with the aid of various methods of statistical analysis. A clear predominance of stationary impulse flows (IFs) was discovered, along with irregularities in such flows, variously expressed and including a significant number of realizations of a regular component of impulse activity. Nonstationary IFs constituted a special variety of BIA; they were found in 15% of the total number of neurons investigated. Serial correlation analysis of the durations of interspike intervals (ISIs), both of stationary and nonstationary IFs, allowed us to identify six main varieties of ISI dynamics in the BIA of neurons of the fastigial nucleus. The patterns of recorded IFs and variations in IFs can serve as an adequate indices of the state of cellular activity during intracellular recording from cells of the central nervous system.L. A. Orbeli Institute of Physiology, Armenian Academy of Sciences, Yerevan. Translated from Neirofiziologiya, Vol. 23, No. 4, pp. 441–450, July–August, 1991.     

世界蚜虫分类研究进展

本文综述了世界蚜虫分类研究进展。内容包括形态分类、细胞分类、生物化学分类以及化石研究等,并以M.L.Sharma的文献目录为基础,对世界蚜虫分类研究报告篇数进行统计。结果表明:世界各国蚜虫分类研究进展极不平衡,美国、加拿大、日本及欧洲的一些国家包括荷兰、丹麦、瑞典、捷克、波兰、德国等其α分类任务基本完成,印度也进展较快,离完成α分类任务为期不远。苏联欧洲部分也已基本完成,亚洲部分和中国尚有大量α级分类工作有待完成。     

Genetic analysis of Escherichia coli K-12 mutants defective for the structural and regulatory genes for second purine nucleoside phosphorylase

Two types of mutants lacking the second purine nucleoside phosphorylase (PNPase 2) activity were isolated using the Escherichia coli K-12 pndR strains with constitutive or inosine-inducible synthesis of the PNPase 2. The mutations of the first type are recessive to the pndR+ allele on the F' episome. They are closely linked to the original pndR+ mutations and therefore affect the pndR gene encoding the activator protein. The mutations of the second type affect the PNPase 2 structural gene (pndA) and are recessive to the pndA+ allele on the F' episome. The nupC-pndR-pndA-ptsH-cysA gene order was established by means of four- and five-factorial transductional crosses.     

固氮蓝藻高光放氢突变种的筛选和放氢特点

作者以前报道过几种快速生长的固氮蓝藻在某种条件下能好气光放氢,其速度可以达到光合放氧速度的10—15%,但这种活性只有在不积累氢气的流动气相下或在短时间内发生。本文报道用亚硝基胍诱变所得到的Anabaena spp。Strain CA的高光放氢突变种——N9A和18A——的筛选和氢代谢特点。在达生长饱和光照以后,野生型的光放氢活性与光照强度的增加成正相关,而其吸氢活性则与之成负相关,显示高光照强度可能抑制吸氢酶的活性。无论在什么光强下,均测不到两个突变种的吸氢活性,暗示在突变种中,吸氢酶或有关系统受损伤。把细胞固相化在琼脂上,在密闭系统中,高光强下培养50个小时,两个突变种光释放和积累的氢分别为野生型的2倍(N9A)和6倍(18A),后者等于氢占气相(1%CO_2的空气)的1.8%。两个突变种在生长速度、叶绿素含量、乙炔还原活性以及光合放氧方面与野生型无明显不同。当以含50—100nM的镍离子的培养基培养时,野生型的好气净产氢活性完全丢失,其吸氢活性却增加约10倍。培养基中镍离子的存在,对两个突变种的高光放氢活性则毫无影响,而且在此情况下,仍测不出其吸氢活性。实验结果表明,这两个突变种系吸氢酶缺陷型突变种。