乙型脑炎病毒NS2A-C60A位点突变对其生物学特性影响研究*

目的:旨在探索Ⅰ型日本乙型脑炎病毒传代致弱后基因组突变NS2A-C60A对乙脑病毒生物学特性的影响。方法:首先通过对传代致弱及原始乙脑毒株基因组序列进行测序比对、结构预测分析并利用Western blotting(WB)确定了目标研究位点NS2A-C60A;然后使用反向遗传定点突变技术构建拯救了包含NS2A-C60A单点突变的病毒株;最后利用噬斑形态观察、生长曲线、双萤光素酶分析,WB以及炎性因子检测和动物实验研究了该单点突变对于乙脑病毒生物学特性的影响。结果:首次研究发现Ⅰ型乙脑病毒传代致弱会导致NS1'蛋白表达的显著下降以及可能的相关位点NS2A-C60A,并成功拯救获得了NS2A-C60A单点突变毒株rJEV-C60A,研究发现NS2A-C60A突变对乙脑病毒的生长特性及噬斑形成没有显著影响,但是能够显著降低乙脑病毒NS1'蛋白的表达,并且该位点突变能够轻微阻碍乙脑病毒对细胞炎性因子表达的抑制,动物实验结果显示NS2A-C60A点突变病毒与原毒株具有相似的神经毒力,说明该位点突变不是影响乙脑病毒毒力致弱的关键位点。结论:新发现的NS2A-C60A位点突变能够显著减少乙脑病毒NS1'蛋白的表达,但是对其增殖、诱导炎症及神经毒力等生物学特性没有显著影响。     

竹链蚧属一新种记述(同翅目:蚧总科)

在皖南山区调查竹类蚧虫,发现竹链蚧属一新种,现描述如下。模式标本保存于安徽省马鞍山市科委业务科。 竹秆红链蚧Bambusaspia rutilan新种 雌成虫 虫体近卵形,深红或紫红色;长约0.8毫米,宽0.45毫米。缘8字腺一列,后     

Ultrastructure of the micropyle and its relationship to pollen tube growth and synergid degeneration in sunflower

Summary Ultrastructural studies made on the micropyle of sunflower before and after pollination resulted in the following observations. (1) The micropyle is closed instead of a hole or canal. The inner epidermis of the integument on both sides of the micropyle is in close contact at the apex of the ovule. The boundary between the two sides consists of two layers of epidermal cuticle. (2) The micropyle contains a transmitting tissue. The micropyle is composed of an intercellular matrix produced by the epidermal cells of the integument. (3) The micropyle is asymmetrical, and is much wider on the side proximal to the funicle. On the funicle side the cells adjacent to the micropyle are similar to those of the transmitting tissue: they have large amounts of intercellular matrix and contain abundant dictyosomes, rough ER, and starch grains, and provide an appropriate environment for growth of the pollen tubes. The cells distal to the funicle are rich in rough ER and lipid bodies; they lack large intercellular spaces. (4) The micropyle is variable in the axial direction, i.e., it is much larger and more asymmetric at the level distal to the embryo sac than at a level close to the embryo sac. After pollination, one to four pollen tubes are seen in a micropyle. During their passage through the micropyle, most pollen tubes are restricted to the side proximal to the funicle. There is a greater tendency (81%) for the degenerate synergid to be located toward the funicle, i.e., at the same side as the pollen tube pathway. The data indicate a close relationship between micropyle organization, orientation of pollen tube growth, and synergid degeneration.     

Measurement of free amino acid levels in ultrafiltrates of blood plasma by high-performance liquid chromatography with automatic pre-column derivatization

Although there are many techniques available for the analysis of amino acids, deproteinization is still one of the major problems in the analysis of amino acids in physiological fluids. The method used to prepare the plasma and to remove the plasma protein has a marked effect on the final results. The most widely used method of deproteinization is precipitation with 5-sulphosalicylic acid followed by centrifugation to remove the precipitated protein. We have not had success in using this deproteinization agent for the analysis of plasma amino acids by a high-performance liquid chromatographic method with automatic pre-column o-phthaldialdehyde—3-mercaptopropionic acid and 9-fluorenylmethyl chloroformate derivatization because of the adverse effect of the sulphosalicyclic acid supernatant on the quantitation and separation. Ultrafiltration was used as an alternative method for the preparation of plasma samples in this experiment. The results were satisfactory for the analysis of plasma amino acids in 1500 samples during a period of four years. Some factors that might influence the results of the ultrafiltration were investigated.     

樟叶蜂的生物学和防治

樟叶蜂是樟树幼苗的主要害虫之一。田间世代重叠。在广州,室内饲养年1—7代,以老熟幼虫于土中茧内越冬。卵单个地散产于嫩叶组织内,幼虫取食嫩叶,对樟树幼苗造成严重损害。幼虫老熟时下地入土结茧。两性或孤雌生殖。幼虫四龄。预蛹期常滞育。 室内试验表明:对2—3龄幼虫喷射90%敌百虫晶体100,000倍或200,000倍液;80%敌敌畏乳剂100,000倍液:40%乐果乳剂30,000倍液;50%杀螟松乳剂10,000或20,000倍液:50%马拉松乳剂10,000或20,000倍液;80%易卫杀可溶性粉5,00或10,000倍液;25%可湿性西维因2,000或4,000倍液;20%除虫菊脂乳剂2,000或4,000倍液;以及27.5%杀虫双乳剂10,000或20,000倍液或25%杀虫净乳剂2,000或4,000倍液(加洗衣粉0.025%)均有良好效果。     

新疆副新蚤属一新种记述(蚤目:毛蚤科)

球副新蚤Paraneopsylla globa新种 鉴别特征 本新种与深窦副新蚤(P.ioffi Tiflov,1937)的形态比较相似,其主要区别是新种第9腹板后臂前缘近端处明显前凸,后缘虽微凹但未形成深窦,端部纯圆,未形成背角;阳茎钩突除端部膜状增宽外,基部尚赘生大的球形膜状物。新种♀第7腹板端缘上叶突出比较狭小。 形态记述 头部(图1)额瘤齿状,嵌于额缘近下1/4处。下唇须约达前足基节长的3/4—4/5。额宗列3—4支宗,均较细小。眼宗列3支宗,较粗长。后头宗3列,依次为1—2、2—3、5—6支,前两列除下位宗外均较细小。 胸部(图1):前胸栉两侧共有栉刺14支,栉前有一列宗4—6支。中胸背板有两列较完整的宗,其前尚有不少小宗,颈片每侧具假宗1—3支。 部分标本后胸背板后缘有1—2个端齿。前足基节外面有宗40—50支。后足基节内面有细宗25—40支,多位于近     

石化基地生态环境系统脆弱性演化机理——以连云港为例

通过梳理国内外文献,挖掘脆弱性本质,提出普遍适用于生态系统脆弱性的PIR理论框架,并从人-环境耦合角度构建演化模型探究石化基地生态环境系统脆弱性演化机理。研究发现：生态系统脆弱性来源于压力扰动,体现在暴露性与敏感性的联合效应,而最终取决于弹性应对影响的状态。石化基地是一个多层次闭环系统,在压力影响下,暴露性、敏感性及弹性彼此间的双重导向作用决定着脆弱性的演化进程;内外部人文与环境因素变化是脆弱性的潜在驱动力,而压力源增多、暴露比例扩大、敏感性上升、弹性退化以及缺乏环境治理能力是加剧脆弱性的具体表征。以欠发达地区连云港石化基地为例,模拟其系统脆弱性演化过程,并从压力、暴露性、敏感性、自我恢复能力和人工修复能力方面构建评价指标体系。结论与建议不仅对石化基地所在欠发达地区的可持续发展具有启示意义,还为其生态环境系统脆弱性的进一步评价提供理论依据。