Nonselective oviposition by a fastidious insect: the laboratory host range of the melaleuca gall midge Lophodiplosis trifida (Diptera: Cecidomyiidae)

Invasion by the Australian paperbark, Melaleuca quinquenervia, has degraded large areas of south Florida wetlands. Restoration of these wetlands requires the removal of expansive monocultures of this large tree while simultaneously curtailing its spread. Management strategies developed by federal and state agencies include biological control to halt the spread of this species and to prevent reinfestation of cleared areas. This requires biological agents able to reduce flowering, seed production, and growth while increasing mortality of seedlings and saplings. Two of the three introduced agents (Oxyops vitiosa Pascoe and Boreioglycaspis melaleucae Moore) partially meet these needs but outcomes are not spatially or temporally consistent. Thus, additional agents are needed. The bud-gall fly Fergusonina turneri Taylor, with its mutualistic nematode Fergusobia quinquenerviae Davies and Giblin-Davis, is actively being released but has not established. A fourth promising agent, the gall midge Lophodiplosis trifida Gagné, manifested an extremely narrow host range during laboratory testing. Oviposition was indiscriminant in caged environments. Small, incipient, unilocular galls were initiated on Melaleuca viminalis, but larval development ensued only on M. quinquenervia. The unilocular galls on M. viminalis did not grow and produced no adult flies. As a result, M. viminalis test plants suffered only minor cosmetic damage. Observations from both Australia and Florida attest to the ability of this midge to impede M. quinquenervia growth and kill small plants. Thus, L. trifida is safe to release and will likely contribute to management objectives for control of this pernicious wetland invader.     

Adenovirus-mediated expression of pig α(1,3) galactosyltransferase reconstructs Gal α(1,3) Gal epitope on the surface of human tumor cells

INTRODUCTIONGal a(1, 3) Gal (gal epitope) is a carbohydrate epitope, which is produced in large amounton the cells of pigs, mice and New World monkey(monkey of South America) by the glycosylationenzyme G alal 1 ) 4G IcNAc3- a- D- galactosyltransferase[or(1, 3)GT; EC2.4.1.511111. This enzyme is active in the Golgi appaxatus of cells and transfers galactose from the sugandonor uridine diphoSphate galactose (UDP-galactose) to the acceptor Nacetyllactosamine residue (Galaal-4GlcNAc-R…     

胶质瘢痕对神经系统损伤的保护作用

胶质瘢痕是神经系统损伤后由反应性星形胶质细胞,小胶质细胞及其分泌的细胞外基质组成。早期的研究多集中于胶质瘢痕在抑制轴突生长,神经细胞再生等方面的作用。而最新的研究表明胶质瘢痕的形成对损伤急性期神经细胞具有重要的保护作用。本文从瘢痕组织在损伤缝合和组织重构、局部免疫调节、神经再生等方面对神经损伤的保护作用进行综述。     

西双版纳30个橡胶树品种的低温半致死温度及低温对抗氧化系统的影响

采用低温恒温槽处理离体叶片后测定其电解质外渗率,并结合Logistic方程得出低温半致死温度的方法,评价农业部景洪橡胶树种质资源圃中的30个橡胶树品种的抗寒性。结果表明,品种‘RRIM712’、‘云研80-1983’、‘云研77-4’、‘PR107’、‘RRIM524’抗寒性强,低温半致死温度在-4～0℃之间;品种‘云研76-398’、‘RRIM523’抗寒性弱,低温半致死温度在4~7℃之间;其他品种抗寒性居中。橡胶树在低温胁迫下,超氧阴离子的产生速率与橡胶树的抗寒性无直接关系,但不同温度下的变化幅度越小,抗寒性越高;SOD活性随温度降低迅速提高,CAT随温度降低表现出活性降低的趋势。     

HBV preS/S基因克隆及其在酿酒酵母中的表达

目的:探索利用酿酒酵母系统表达乙型肝炎病毒(HBV)preS／S基因。方法:利用PCR技 术,以HBV病毒DNA为模板,体外扩增HBV preS／S基因。然后构建重组表达载体pESC-preS／S。 用LiAc法转化酿酒酵母YPH50,选取重组菌进行培养,并诱导表达外源蛋白。提取蛋白浓缩后 进行SDS-PAGE分析,并经Western blot分析鉴定。结果:实验结果表明重组菌能够表达HBV preS／S蛋白。结论:利用酿酒酵母系统可成功表达HBV preS／S基因,为制备新型预防性疫苗提供 条件。     

西藏南部岗巴地区白垩纪中期钙质超微化石带和Cenomanian-Turonian界线

我国西藏南部海相白垩系含有较丰富的钙质超微化石。文中着重研究岗巴地区两个剖面 (即剖面A ,B)Albian Santonian钙质超微化石的分布。根据标志种的存在 ,识别出 5个初现面事件 ,相应地建立 6个钙质超微化石带 ,自下至上是Prediscosphaeracretacea带 ,Eiffellithusturriseiffeli带 ,Lithraphiditesacutum带 ,Gartneragoobliquum带 ,Quadrumgartneri带 ,Lucianorhabduscayeuxii带。同时 ,通过洲际对比 ,建议以G .obliquum初现面作为划分本区Cenomanian和Turonian界线的标志。此外 ,Q .gartneri带和I .cayeuxii带之间缺失多个化石带 ,据此推测Turonian至Santonian期间本区可能存在沉积间断。     

刈割时间和次数对牧草产量和品质的影响

研究了刈割时间和频率对牧草产量和品质的影响,结果表明：刈割间隔时间的延长使牧草的茎／叶比值和粗纤维含量显著增加,粗蛋白、粗灰分、Ｐ、Ｋ等的含量显著下降,其中Ｋ下降的幅度最大,其次是粗灰分、粗蛋白和Ｐ等．刈割时间对粗脂肪、Ｃａ、Ｍｇ的含量影响不大,没有统计学上的差异．适宜的刈割频率可提高牧草的产量和质量,隔５０－５５ｄ收割１次,可使牧草的产量和质量均维持较高的水平,隔５７ｄ割１次,牧草的蛋白质含量略有下降,而粗纤维含量却有不同程度的上升．     

不同孵化湿度下的乌龟卵孵化成功率及新生幼体特征

A total of 51 Chinese three-keeled pond turtle Chinemys reevesii eggs were incubated on wet and dry substrates (water potentials of - 12 kPa and - 300 kPa, respectively) at 30℃ to assess the influence of the hydric environments on egg survival and hatchling traits. Eggs incubated in the dry condition lost weight, whereas those incubated in the wet condition did not. The hydric environments did not affect incubation lengths (60.3 vs 60.7 days) as well as hatching successes (69.2% vs 88.0% ). Except for wet body mass and carapace width, which were larger for hatchlings from the -12 kPa treatment than from the -300 kPa treatment, the hydric environments did not affect most hatchling traits. These unaffected traits included dry body mass, carapace length, tail length, limb length, hatehling components (carcass, residual yolk and fat bodies), swimming performance and critical thermal minimum. In conclusion, within the water potential of -12 to -300 kPa, hydric environments have little effect on embryonic development and hatchling traits in Chinese three-keeled pond turtles [Acta Zoologica Sinica 50 (1) : 133 - 136, 2004].     

‘津田’芜菁Transparent Testa Glabra 1（BrTTG1）基因的克隆及表达分析

TTG1（Transparent Testa Glabra 1）蛋白是一种WD40类蛋白,参与植物的生长和发育。采用RT-PCR方法从芜菁品种‘津田＇中克隆了BrTTG1 cDNA序列（GenBank登录号HM208590）。该基因cDNA开放阅读框长度为1 014 bp,编码一个由337个氨基酸残基组成的蛋白,该蛋白分子量为37.28 kDa,理论等电点为4.66。与其他植物中的TTG1蛋白进行同源性比对结果显示,BrTTG1与甘蓝型油菜的TTG1同源性最高。BrTTG1蛋白在31～337位氨基酸处含有WD40超家族的保守结构域。荧光定量PCR检测BrTTG1在‘津田＇芜菁不同组织中的表达结果表明,该基因在有花青素合成的红色‘津田＇芜菁根皮中表达量最高。     

湖北安陆新的恐龙蛋类型的发现及其意义

本文记述的恐龙蛋化石标本,采自湖北省江汉盆地公安寨组下部.蛋化石保存完好.在普通光学显微镜和扫描电镜下观察,蛋壳的显微结构完整,清晰可见.根据钙质蛋壳基本结构单位的形态及排列特征,笔者建立了—新属,新种——Dendroolithus wangdianensis gen. et sp. nov.,代表恐龙蛋类一个新科——Dendroolithidae fam. nov.此外,残存的卵壳膜纤维化石的发现,将为进一步研究恐龙蛋卵壳膜的结构和氨基酸组成提供宝贵材料.