Composition and Distribution of Free Amino Acids in Flatpea (Lathyrus sylvestris L.) as Influenced by Water Deficit and Plant Age

Drought-stressed flatpea (Lathyrus sylvestris L.) plants from8 to 22 weeks old were analysed for nitrogen, soluble proteinand free amino acids. An increase in nitrogen and free aminoacid concentrations and a decrease in soluble protein levelwere observed in roots of plants up to 16 weeks old. The cumulativeconcentration of free amino acids increased with drought stress.Tissue concentrations of 2, 4-diaminobutyric acid (1.6–2.6%of the dry weight) were highest in leaves. Levels increasedsteadily, nearly doubling, in leaves and stems between weeks10 and 16. Levels in drought-stressed leaves were, on average,11.9% higher than those of controls. Estimated concentrationsof a mixture of 4-aminobutyric acid and an unknown amino acidwere highest in stems, increased in this tissue with age andtended to increase in stems and leaves and decrease in rootsin response to water deficit. Levels of the mixture of homoserineand another unidentified amino acid were not influenced by ageor water status of the plants. Root concentrations of asparagine,arginine, glutamine, aspartate, and another prominent, unidentifiedamino acid increased with plant age and reached a peak at thetime of flowering (14 to 18 weeks). Only the concentration ofthe unknown compound was elevated following drought stress.Concentrations of valine, isoleucine, leucine, phenylalanine,and methionine also increased during this period and were elevatedin drought-stressed plants. Proline levels increased with plantage and drought stress, but proline accounted for only about10% of the total free amino acids in the drought-stressed plants. Key words: 2, 4-Diaminobutyric acid, drought, flatpea     

艾菲属吸虫一新种（复殖目：鳞肉科）

艾菲属(Aephnidiogenes)吸虫在我国为首次报道,文中记述了采自海南岛一种胡椒鲷(Plectorhynchus pictus)体内的海南艾菲吸虫,新种(Aephnidiogenes hainanensis sp. nov.),对其形态特征进行了描述,并与相近种作了比较。虫体11.641—17.425mm,卵巢为不规则三角形,卵子66—69×33—45μm。     

长非编码RNA PVT1与消化系统肿瘤

长非编码RNA（long non-coding RNAs, lncRNAs）在肿瘤发生、发展进程中承担重要角色,是近年来的研究热点之一。大量研究表明,浆细胞瘤变异易位基因1（plasmacytoma variant translocation 1, PVT1）可通过多种分子机制参与调控消化系统肿瘤的增殖凋亡、迁移侵袭、细胞自噬、血管生成、多药耐药及肿瘤代谢等过程,从而发挥致癌作用。本文主要就PVT1在消化系统肿瘤中的表达水平变化,及其与临床病理特征和预后的关系,以及PVT1对消化系统肿瘤的致癌作用机制和多药耐药机制等研究进展作一综述。     

玉米叶绿体atpB及atpE基因在大肠杆菌中的表达

本实验构建了在大肠杆菌中能表达玉米叶绿体ＣＦ１完整β亚基、缺失Ｎ端２３个氨基酸残基的β亚基以及完整ε亚基的表达质粒。ＳＤＳ－聚丙烯酰胺凝胶电泳及Ｗｅｓｔｅｒｎｂｌｏｔ实验表明,在分别含这些表达质粒的细菌中β、ε亚基蛋白的合成量在诱导３ｈ后即达到饱和,其含量各占细菌体总蛋白的１０％左右。这些表达产物在细菌体中形成不溶性的包含体。可通过对菌体蛋白的分级分高,将表达产物溶于５ｍｏｌ／Ｌ的尿素溶液中。     

转铁蛋白分型及其基因频率分布

用固相pH梯度(pH 5.05～5.60)等电聚焦技术对随机抽取的188名北京地区健康汉族人的血清转铁蛋白(Tf)进行分型调查,并统计基因频率,检出了在中国还未见报道的Tf^C3基因.其表型分别是：TfC1, TfC2, TfC1C2, TfC1C3, TfC1Dchi, TfC2Dchi.Tf^C1=0.7420, Tf^C2=0.2420, Tf^C3=0.0027, Tf^Dchi=0.0133, 符合Hardy-Weinberg定律, 并与其他已见报道的汉族 Tf基因频率大致相符.     

胡桃科植物的化学和机械抗虫机制与果实被害程度的关系

胡桃科植物含有数种化学物质,如胡桃醌(Juglone 5-羟基1,4-对醌)(Bode 1958;Brooks 1951;Davies 1928; Massey 1925),胡桃油,皂角甙(Saponin)(Petrides 1970; Whittaker and Feeny 1971)和丹宁(Tannin)(Nierenstein 1934; Pridham 1960; Kingsbury 1964; Haslam 1966),这些物质对植物和害虫均有一定的影响。此外,胡桃科植物的果实总是有一层厚厚的外果皮和坚硬的种壳,保护着核仁,起机械抗虫作用,以减少害虫的危害。本文就这两种抗虫机制与果实被害程度的关系进行研讨。     

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