引致河蟹颤抖病的病毒的核酸定性

对河蟹(中华绒螯蟹)“颤抖病”病毒及其核酸进行了电镜观察。纯化病毒经负染后由电镜观察显示,病毒粒子呈球状,有囊膜和纤突,直径约为150nm。纯化病毒经核酸酶降解杂核酸后,加入8mol/L尿素释放病毒核酸,经水相法展开后,用覆有碳膜的铜网取样,再经染色和真空镀膜,于电镜下观察。病毒核酸呈单股线状,底片经光学精确放大后,测定了核酸分子的长度,根据经验公式计算出病毒核酸分子量为5.05×106。抽提的病毒核酸在0.8%琼脂糖凝胶电泳中呈单一条带,大小为15~16kb,经核酸酶酶切显示,核酸对DNaseI不敏感,对RNase、MungBeanNuclease敏感,根据以上特性判断,该核酸为ssRNA。     

中华绒螯蟹呼肠孤病毒样病毒病研究

为了探讨中华绒螯蟹(Eriocheir sinensis)颤抖病的发生原因,从表现出颤抖症状的中华绒螯蟹中初步分离纯化出一种病毒,人工感染健康触,出现明显的阳性反应,并从人工感染的蟹的血液、肠道、性腺等组织中检测到病毒,表明分离到的病毒为中华绒螯蟹的病原 ,且对野生锯齿华溪蟹(Sesarnadehanni)也具感染性.电镜观察结果显示该病毒粒子呈球状,无囊膜,大小为55nm左右.病毒核酸在1%琼脂糖凝胶电泳中,电泳图谱呈现3/3/4/2型,总分子量约20kb.该核酸对DNaseⅠ不敏感,对RNase敏感,推测病毒核酸为dsRNA,从病毒形态大小、病毒核酸等特性初步确定该病毒为呼肠孤病毒样病毒(Reovirus-like Virus).该研究为探讨中华绒螯蟹颤抖病的发生原因及防治方法有很大的指导意义.     

小鹅瘟病毒核酸链型与结构蛋白分析

采用简易方法从鹅胚中分离纯化的小鹅瘟病毒(GPV)样品相当纯净,以致在电镜下呈晶格排列。用负染色技术观察病毒的形态结构,病毒直径为18～20nm,无囊膜。病毒颗粒含有4种结构蛋白,其分子量分别为88、78、66和51kd。根据病毒的核酸链型分析,小鹅瘟病毒含有单链核酸。此结果支持了小鹅瘟病毒属于细小病毒属的结论。     

一株新的草鱼出血病病毒分离物的特性

从湖南邵阳地区患出血病的草鱼组织中分离到一株病毒,经部分提纯、负染后,电镜观察,揭示为双层衣壳、直径约71nm的球形颗粒。其核酸在聚丙烯酰胺凝胶电泳中呈现11条带。经核酸酶消化、吖啶橙染色及核酸的变性试验,证明为双链RNA。病毒在草鱼肾细胞株(CIK)单层细胞上,形成直径约2mm的空斑;对温度有一定稳定性;对乙醚、氯仿不敏感;经pH3、10处理后仍能保持相对稳定的滴价。此病毒不属业已建立的呼肠孤病毒科6个属中的任何一个属,而可能为呼肠孤病毒科中一新成员。     

兔出血症病毒核酸的某些理化性质的研究

本文对我国无锡分离的兔出血症病毒A_2R-3毒株核酸的某些理化性质进行了研究。采用孚尔根染色、二苯胺反应和核酸酶解实验证实病毒核酸为DNA类型。吖啶橙染色、甲醛反应、核酸酶S_1消化和核酸热变性实验表明病毒核酸为单链型。核酸电泳呈单一组分。电境观察显示核酸分子链呈线状,平均长度约为2.15μ。计算分子量约为2.1—2.5×10~6d。核酸碱基组盛为A25.34、T29.37、G23.85、C21.43、(G C)克分子百分比值为45.28。结合以前的报道、我们认为:兔出血症病毒可以归类于细小病毒科。     

草鱼出血病病毒抗原亚单位的研制

通过比较溶液的离子浓度对病毒形态的结构的影响,发现ＧＣＨＶ在低盐溶液盐低温（－２０℃）保存条件下,外壳蛋白会自动降解,但不十分完全,采用含１％ＮＰ４０（Ｎｏｎｉｄｅｔ－ｐ４０）的稀盐溶液处理感染病毒的细胞,经冻融及差异离心,电镜下观察到纯度较高的病毒双层衣壳,核心衣壳及散在的子粒。纯化的病毒亚单位用核酸酶消化后,与等量的福氏佐剂混合,免疫家兔制备抗体,该抗血清经台和试验测定,显示了较强的中和病毒的     

一株奥奈达希瓦氏菌烈性噬菌体的分离、纯化及鉴定

【目的】从环境中分离获得希瓦氏菌烈性噬菌体,并对其性质进行研究。【方法】以4株希瓦氏菌为宿主菌,采用双层平板法从污水样品中分离得到奥奈达希瓦氏菌MR-1烈性噬菌体M1;观察噬菌斑特征;利用超速离心法浓缩M1颗粒,进一步用氯化铯密度梯度离心纯化;采用透射电子显微镜观察纯化的M1颗粒;提取M1核酸,通过核酸酶处理分析其核酸类型及结构;绘制一步生长曲线。【结果】噬菌体M1在双层平板上形成圆形的噬菌斑,清晰透明,边缘光滑,直径为2.3 mm-2.5 mm;经电镜观察,噬菌体M1头部呈二十面体,直径约为55 nm,尾长约为170 nm,尾部可收缩,属于肌尾噬菌体科(Myoviridae);通过酶切分析表明噬菌体M1核酸为线形双链DNA;一步生长曲线显示该噬菌体感染后完成一个复制循环所需要的时间约为15-20 min。【结论】噬菌体M1属肌尾噬菌体科,研究结果为后续研究病毒在地球微生物成岩过程中所起的作用提供了实验材料。     

鸭胚成纤维细胞中鸭瘟强毒的增殖特性研究

通过细胞培养物光学显微观察、细胞超薄切片研究、定量PCR检测技术对鸭胚成纤维细胞中鸭瘟强毒的增殖特性进行了研究.结果表明:鸭瘟强毒接种鸭胚成纤维细胞后42 h,可使细胞培养物出现大量明显的蚀斑病变.细胞培养物的超薄切片电镜观察研究表明,病毒核酸在胞核内常集中分布,呈直径35～45 nm的圆形颗粒状;核衣壳在胞核和胞浆内都有分布,呈直径90～100 nm的网形颗粒状;成熟病毒位于胞浆空泡内,呈直径150～300 nm的圆形,有囊膜和皮层结构;病毒通过囊膜与胞膜融合入侵细胞,在核内生成核酸、装配核衣壳,在胞浆中得到皮层,出芽到胞浆空泡内获得囊膜,通过胞吐作用释放到胞外.定量PCR研究表明:鸭瘟强毒接种细胞后10 h开始明显复制,接毒后30 h时含量趋于稳定,接毒后22 h时开始向胞外释放,50 h时达最大值,细胞和上清中病毒含量的增幅均为103左右,病毒主要存在于细胞中,其含量为上清的102～103倍.     

新型多价大肠埃希菌噬菌体285P生物学特性研究

筛选多价大肠埃希菌噬菌体,确定其宽噬宿主谱、形态大小及核酸类型等基本特征,为应用于环境微生物消毒奠定基础。应用双层琼脂平板法确定多价噬菌体的宿主谱;透视电镜观察形态结构;提取核酸,并利用分光光度法和核酸酶(DNase、RNase A及S1)酶切的方法对核酸进行鉴定;SDS-PAGE电泳分析噬菌体膜蛋白。大肠埃希菌BL21、DH5α、JM109为噬菌体285P的宽噬宿主;电镜下呈微球型,边缘光滑,短尾,颗粒直径约81 nm;分光光度法及核酸酶切法均证实核酸为双链DNA;膜蛋白略小于43 ku。噬菌体285P对多株大肠埃希菌具有宽噬作用,对环境中微生物的控制具有潜在的应用价值。     

一株貂肠炎病毒某些特性的研究

采用猫肾传代细胞FK增殖华东地区分离的貂传染性肠炎病毒(mink infectious enteritis virus,MEV-S_1)能产生明显的细胞病变。浓缩的病毒液经Sepharose-4B柱层析提纯处理后置电镜下观察,可见典型的病毒粒子。经蛋白酶K、SDS裂解病毒,用苯酚-氯仿法抽提病毒核酸,二苯胺试验和酶消化试验表明该病毒核酸为DNA类型。吖啶橙染色试验表明该DNA为单链。甲酰胺法进行核酸分子展层,病毒核酸呈线状,长度为1.5～2.0/μm。     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

On the Dependence of the Quadratic Risk of the Classical Predictor and the Prediction-Horizon

When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.     

中国植物区系与其它地区区系的联系及其在世界区系中的地位和作用

基于吴征镒将中国全部种子植物３２３８个属的分布区划分为１５个大类型和３４个变型的基础上,简要地讨论了中国植物区系与其它地区区系的联系,以及它在被子植物起源方面的作用。主要论点如下：（１）与热带亚洲区系的联系。这种联系主要通过第７类型（热带亚洲分布）及其５个变型来体现的。本文列举了１０个科,龙脑香料、狭义隐翼科、交让木科、五隔草科、五列木科、肉实树科、心翼果科、八宝树科、兰花蕉科和四数木科,来说明这