黑质升压和弓状核降压效应及二者间的机能联系

本工作用神经元胞体兴奋剂L-谷氨酸钠(Glu)注入箭毒化、人工呼吸大鼠的下丘脑弓状核(AR),引起血压下降,心率减慢;多巴胺(DA)受体激动剂去水吗啡注入AR和Glu注入黑质(SN)均产生升压和加速心率的效应,Glu(i.SN)效应可被DA受体阻断剂氟哌啶醇注入双侧AR阻断;从而证明:(1)AR具有降压、降心率功能;(2)黑质可通过AR内的DA受体对AR降压、降心率效应起抑制作用,而实现其加压、加速心率效应。     

Genetic organization and nucleotide sequence of the stability locus of IncFII plasmid NR1

The stability (stb) locus of IncFII plasmid NR1 was mapped to a 1700 base-pair NaeI-TaqI restriction fragment. A series of unstable plasmids that contained insertion, deletion, and point mutations that inactivated the stability function was isolated. The unstable point mutants examined were all stabilized (complemented) in trans by a copy of the wild-type stb locus, suggesting that the mutations had inactivated diffusible gene products. The nucleotide sequence of the stb locus contained two tandem open reading frames, designated stbA and stbB, that encoded essential trans-acting protein products with predicted sizes of 36,000 Mr and 13,000 Mr, respectively. A third open reading frame, stbC, that could encode a peptide of 8000 Mr was contained within stbB in the complementary DNA strand. Plasmid-encoded proteins of 36,000 Mr and 13,000 Mr were identified in minicell experiments as the products of stbA and stbB, respectively. Unstable deletion mutants that retained the promoter proximal region of the stb locus upstream from stbA but had deleted both stbA and stbB were stabilized in trans by plasmids that could supply StbA and StbB. In contrast, deletion mutants that had lost the stbAB promoter region were not complemented in trans, indicating that this region contained an essential cis-acting site (or sites). Unlike some other loci that mediate stable plasmid inheritance, cloned copies of the wild-type stb locus of NR1 did not exert strong incompatibility (i.e. trans destabilization) against other stb+ derivatives of plasmid NR1 present in the same cell.     

数种昆虫5S rRNA结构特点的比较

比较已知结构的昆虫5S rRNA的核苷酸顺序,发现同科、同目的昆虫比不同科、不同目的昆虫有较少的核苷酸差别.根据Kimura和Ohta(1972)提出的经验公式,绘制了数种昆虫的系统发育图.结果表明,从分子进化得到的结论和经典分类基本上是一致的.根据DeWachter等(1982)提出的二级结构模型,归纳分析这些昆虫5S rRNA,发现保守位点与半保守位点(同一位点仅出现二种核苷酸残基)之和几乎占整个5S rRNA分子的100%.     

Serum IgE levels in rats infected with Paragonimus westermani]

Paragonimus westermani is a common fluke in Korea. The present study aimed to determine serum total IgE and specific IgG levels in experimental paragonimiasis of rats. Each Wistar rat was inoculated orally with 20-25 metacercariae of P. westermani from Cambaroides similis. Before and after infection (1, 2, 3, 4, 6, 8 weeks) of P. westermani, the blood was collected from the retro-orbital venous plexus of rats and kept serum at -70 degrees C. Serum total IgE and specific IgG levels were determined by the capture and conventional enzyme-linked immunosorbent assay, respectively. The results were as follows; 1. Serum IgE values were increased to 0.18 +/- 0.042 at 2 weeks, 0.28 +/- 0.151 at 4 weeks and 0.43 +/- 0.055 at 8 weeks after infection. The absorbances of non-infected rats ranged 0.07 +/- 0.021-0.12 +/- 0.025. 2. Specific IgG values were slightly increased at 3 weeks (0.20 +/- 0.032) and gradually increased up to 8 weeks (0.31 +/- 0.067) after infection. The absorbances of non-infected rats ranged 0.11 +/- 0.035-0.18 +/- 0.019. The present results suggested that P. westermani could elevate serum IgE and specific IgG antibodies in Wistar rats which were not a good definitive host.     

Artificial Induction and Evaluation of a Mild Isolate of Tomato Spotted Wilt Virus

A severe isolate (BL) of tomato spotted wilt virus (TSWV) that originated from Hawaii was treated with nitrous acid in an effort to obtain mild mutants. The standardized procedure used in mutation experiments was: extracting infected Gomphrena globosa L. leaf tissue in 0.01 M Na₂SO₃, 0.125 M sodium acetate and 0.4 M sodium nitrite at pH 5.5 and incubating the extract for 20 min at room temperature. The extract was inoculated to tobacco (Nicotiana tabacum L. cv. Havana 423) and local lesions were subsequently transferred to lettuce (Lactuca sativa L. cv. Minetto). One isolate (R27G) that incited mild symptoms in lettuce was obtained out of 868 local-lesion-transfers. Under greenhouse conditions, the isolate induced mild symptoms on tomato (Lycopersicon esculentum Mill.) but was severe on peppers (Capsicum annuum L.). The effect of the R27G isolate on growth of potted tomatoes kept outdoors was variable. In one trial, only 15 % of the fruit had symptoms versus 67 % in another trial. R27G fully protected Datura stramonium L. plants that were challenge inoculated with the severe parent BL isolate. Less effective cross protection was observed against a severe isolate from Oklahoma.     

记真盔甲鱼类两新属——兼论真盔甲鱼类系统发育关系

本文记述了早泥盆世真盔甲鱼类两新属:憨鱼属(Nochelaspis)和翼角鱼属(Pterogonaspis).真盔甲鱼类是盔甲鱼类的一个单系类群,现有七属十二种,文中运用分支系统学原理对其系统发育关系进行了初步探讨.     

γ-氨基丁酸、荷包牡丹碱和L-谷氨酸钠对猫和家兔同侧和对侧图形视觉诱发电位的影响

在猫和家兔大脑半球一侧视区17/18交界处施加γ—氨基丁酸(GABA)、荷包牡丹碱和L—谷氨酸钠,以及用氯化钾和冷冻阻遏的方法,记录对侧和同侧皮层相应处图形视觉诱发电位(PVEP)的变化。讨论了GABA、荷包牡丹碱和L—谷氨酸钠对猫和兔的对侧和同侧PVEP的影响。     

氯化钠对培养的大鼠主动脉平滑肌细胞的心房钠尿肽受体的调节

培养的卒中型自发性高血压大鼠(SHR_(sp))及其对照 WKY 大鼠主动脉平滑肌细胞(VSMC)上存在心房钠尿肽(ANP)的特异性受体,它们与~(125)I-ANP 的最大结合量(B_(max))是:SHR_(sp)3.65±0.13和 WKY 1.89±0.09 pmol/mg pr(P<0.01);解离平衡常数(Kd)值分别是72.6±10.2和42.0±4.8×10~(-12)mol/L(P<0.01)。 两种细胞内介导舒血管作用的第二信使、环磷酸乌苷(cGMP)的基础浓度无显著差异,对相同剂量 ANP 刺激引起 cGMP 分别增加139(SHRsp)和271(WKY)倍。可见 SHRsp 的 VSMC ANP 受体数量虽比 WKY大鼠增多,但对相同剂量 ANP 引起的 cGMP 增加反应及 ANP 受体的亲和力均显著降低。高盐培养液孵育24h 后,细胞表面 ANP 受体的亲和力改变不明显,但受体数量下调,SHRsp 和 WKY 大鼠分别降至对照的34.8±8.2%和38.6±9.4%,细胞对 ANP 引起的 cGMP增加反应明显降低,且均以 SHR_(sp)较显著。提示后两种变化可能在高盐促进血压升高的机制中起作用。     

Synthesis of a nonacosapeptide (beta-fragment) corresponding to the N-terminal sequence 1-29 of human liver metallothionein II and its heavy metal-binding properties

A nonacosapeptide (beta-fragment) corresponding to the N-terminal sequence 1-29 of human liver metallothionein II was synthesized by the fragment condensation method. The Cd-binding ability of the beta-fragment was much stronger than that of cysteine as thionein and synthetic alpha-fragment corresponding to the C-terminal sequence 30-61 of human liver metallothionein II. Both the alpha- and beta-fragments bound preferentially to Cu ions rather than Cd ions.