Human RNaseP RNA and nucleolar 7-2 RNA share conserved ‘To’ antigen-binding domains

RNase P in both prokaryotes and eukaryotes is a ribonucleoprotein that cleaves tRNA precursors to generate the 5 termini of the mature tRNAs. Many patients with autoimmune diseases produce antibodies against a 40 kDa protein (designatedTo orTh antigen) which is an integral component of eukaryotic RNaseP as well as nucleolar 7-2 RNP which is identical to the mitochondrial RNA processing (MRP) RNP. Interestingly, theTo antigen found in human cells and the C5 protein, the only protein component ofE. coli RNaseP, are antigenically related. In this study, we show that a 56 nucleotide-long sequence, corresponding to nucleotides 20–75 near the 5 end of human RNaseP RNA, is sufficient to bind theTo antigen. We previously showed that the humanTo antigen binds to a short distinct structural domain near the 5 end of human 7-2/MRP RNA. There is no obvious primary sequence homology between theTo antigen binding sites in RNaseP RNA and 7-2/MRP RNA; however, these sequences are capable of assuming a similar secondary structure which corresponds to the recently proposed cage structure for RNaseP RNAs and 7-2/MRP RNA (Forster and Altman (1989) Cell 62: 407–409). These data are supportive of the idea that these two RNAs may have evolved from a common progenitor molecule.     

Variations in Immune Response of Popillia japonica and Acheta domesticus to Heterorhabditis bacteriophora and Steinernema Species

The infectivities of Steinernema carpocapsae, S. glaseri, S. scapterisci, and Heterorhabditis bacteriophora to Japanese beetle larvae, Popillia japonica, and house cricket adults, Acheta domesticus, were compared using external exposure and hemocoelic injection. Only H. bacteriophora and S. glaseri caused high P. japonica mortality after external exposure. When nematodes were injected, P. japonica had a strong encapsulation and melanization response to all species except S. glaseri. Heterorhabditis bacteriophora and S. carpocapsae were able to overcome the immune response, but S. scapterisci was not. All species except S. scapterisci were able to kill and reproduce within the host. Only S. scapterisci and S. carpocapsae caused A. domesticus mortality after external exposure. When nematodes were injected, A. domesticus had a strong immune response to all species except S. scapterisci. Steinernema carpocapsae effectively overcame the strong immune response and caused high host mortality, but S. glaseri and H. bacteriophora did not. Steinernema scapterisci caused high host mortality and reproduced, S. glaseri and H. bacteriophora caused low host mortality but only S. glaseri reproduced, and S. carpocapsae was able to kill the host but reproduced poorly. Most (ca. 90%) of the S. carpocapsae in the hemocoel of P. japonica became encapsulated and melanized within 8 hours postinjection. The symbiotic bacterium, Xenorhabduf nematophilus, was often released before this encapsulation and melanization.     

Specificity and sequence requirements for interactions between various retroviral Gag proteins.

We previously established a genetic assay for retroviral Gag polyprotein multimerization (J. Luban, K. B. Alin, K. L. Bossolt, T. Humaran, and S. P. Goff, J. Virol. 66:5157-5160, 1992). Here we use this assay to demonstrate homomeric interactions between Gag polyproteins encoded by six different retroviruses. Of the Gag polyproteins tested, only those encoded by closely related retroviruses formed heteromultimers. To determine the primary sequence requirements for human immunodeficiency virus type 1 Gag polyprotein multimerization, we studied the effects on multimerization of deletion and linker insertion mutations. Sequences necessary for this process were located between the C-terminal one-third of the capsid domain and the C terminus of the nucleocapsid domain.     

植物细胞离析酶的制备和应用

用 Aspergillus sp．A-19菌经固体发酵研制成一种新的植物细胞离析酶(SeparatasezA—P)。其离析单细胞的酶活力平均为70 767u／g,有效作用的pH在3．0—7．0,温度为20—45℃。发酵培养基配方是麸皮：桔皮粉：(NH₄)₂SO₄(w／w)为100:100:O．63,料水比为1 :2．0,培养适宜条件为25℃、60小时。     

斑须蝽三代卵块的空间分布和田间抽样技术研究

通过田间调查和计算,明确了斑须蝽三代卵块呈聚集分布,且以负二项分布为主。理论抽样数当t＝1．00,D＝0．3时,n＝13．091/＋63．878,如果防治指标定为百株虫卵块12块时,则最大抽样数为173株,序贯抽样的累积虫卵块数量界限为：T0（N）＝0.12N±0．4735。田间随机取样以平行线和Z字形为最佳。     

小麦体细胞胚发生的超微结构研究

对小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）幼胚培养中体细胞胚发生过程的超微结构变化进行了研究,结果如下：（１）原体细胞中大液泡消失,存在大量小液泡,细胞质的电子密度加强,核大,核仁明显,出现多核仁;（２）细胞器数量和种类,如质体、核糖体和线粒体增加;（３）细胞壁加厚,胞间连丝逐渐消失,细胞器数量丰富,胚性细胞中积累淀粉;（４）细胞壁加厚的胚性细胞中存在核仁液泡、自体吞噬泡和分泌泡;（５）多细胞原胚、球形胚和梨形胚被一层外壁包围,但胚体内细胞间广泛存在胞间连丝;（６）成熟胚生长点部位的细胞内质体中出现膜系结构,已向叶绿体转变,类囊体已形成     

Measles outbreak in 31 schools: risk factors for vaccine failure and evaluation of a selective revaccination strategy.

OBJECTIVE: To examine the risk factors for measles vaccine failure and to evaluate the effectiveness of a selective revaccination strategy during a measles outbreak. DESIGN: Matched case-control study. SETTING: Thirty-one schools in Mississauga, Ont. SUBJECTS: Eighty-seven previously vaccinated school-aged children with measles that met the Advisory Committee on Epidemiology''s clinical case definition for measles. Two previously vaccinated control subjects were randomly selected for each case subject from the same homeroom class. INTERVENTIONS: All susceptible contacts were vaccinated, and contacts who had been vaccinated before Jan. 1, 1980, were revaccinated. When two or more cases occurred in a school all children vaccinated before 1980 were revaccinated. MAIN OUTCOME MEASURES: Risk of measles associated with age at vaccination, time since vaccination, vaccination before 1980 and revaccination. RESULTS: Subjects vaccinated before 12 months of age were at greater risk of measles than those vaccinated later (adjusted odds ratio [OR] 7.7, 95% confidence interval [CI] 1.6 to 38.3; p = 0.01). Those vaccinated between 12 and 14 months of age were at no greater risk than those vaccinated at 15 months or over. Subjects vaccinated before 1980 were at greater risk than those vaccinated after 1980 (adjusted OR 14.5, 95% CI 1.5 to 135.6). Time since vaccination was not a risk factor. Revaccination was effective in reducing the risk of measles in both subjects vaccinated before 1980 and those vaccinated after 1980 (adjusted OR reduced to 0.6 [95% CI 0.1 to 5.3] and 0.3 [95% CI 0.13 to 2.6] respectively). However, only 18 cases were estimated to have been prevented by this strategy. CONCLUSIONS: Adherence to routine measles vaccination for all eligible children is important in ensuring appropriate coverage with a single dose. The selective revaccination strategy''s high labour intensiveness and low measles prevention rate during the outbreak bring into question the effectiveness of such a strategy.     

新疆的刺球座属、穴壳属及普氏腔孢属

本文报道了新疆腔菌纲座囊菌目刺球座属(Lasiobotrys)、穴壳属(Dothiora)和普氏腔孢属(Plowrightia)的六种子囊菌,即:忍冬刺球座菌(L.loniccrae)、花楸穴壳菌 (D.sorbi)及其无性阶段花楸疡壳孢(Dothichiza sorbi)、茶蔗子普氏腔孢菌(P.ribesia)、小檗普氏腔孢菌(P.berberidiJ)、沙棘普氏腔孢菌(P.hippophaeos)及雕刻普氏腔孢菌(P.insculpta)。这三个属的真菌在我国均未报道过,为我国新纪录属(种)。标本均采于新疆,保存于新疆八一农学院植保系真菌标本室(HMAAC)。     

九株根霉可溶性蛋白和三种酶的电泳图谱比较研究

本文报导了根霉属(Rhizopus) 9个菌株天然态及解聚态可溶性蛋白、酯酶同工酶、葡萄糖淀粉酶和SOD电泳图谱的比较研究。结果表明：可溶性蛋白图谱和酯酶同工酶谱能显示五种已知供试菌种间的差异,尤其酯酶同工酶谱还能显示米根霉两个供试菌株之间的微小差异。经综合分析全部试验结果后得出的系统树图显示了9个供试菌株间的亲缘关系,并为未知菌株F1(BR12)和Q303提供了鉴定和命名依据。文中首次报导了根霉的SOD同工酶,并对蛋白质和酶电泳图谱用于根霉分类研究进行了讨论。     

大黄素对豚鼠结肠带平滑肌细胞电和收缩性能的影响

联合应用平滑肌肌力张力测量技术和细胞内微电极记录技术,同步地现测豚鼠结肠带平滑肌自发的肌源性电活动和力学活动,研究了大黄素的药物作用。大黄素能缩短膜电位的波动周期,从而缩短峰电位集簇发放的周期;相应地,可使平滑肌的分节律收缩加快,幅值指数升高。大黄素又能促使细胞膜电位自发的周期性波动的出现,导致峰电位的集簇发放;相应地,可使强直收缩转化为分节律收缩,即促进收缩形式向有利于肠道推进功能的方向转化。以上结果表明,大黄素能有效地提高豚鼠结肠带平滑肌细胞的电兴奋性和收缩功能,并且对其电学和力学活动的影响之间有明确的对应关系。