一株玫烟色虫草对草地贪夜蛾的致病性研究

草地贪夜蛾Spodoptera frugiperda(J.E Smith)是我国新发现的一种重要外来入侵害虫。为了寻找对草地贪夜蛾有致病性的昆虫病原真菌,本实验采用浸虫法研究了玫烟色虫草Cordyceps(=Isaria)fumosorosea SCAU-IFCF01对草地贪夜蛾1~6龄幼虫的致病力,通过体视镜观察了幼虫感菌后侵染症状和体表病变过程。结果表明:菌株IFCF01可侵染草地贪夜蛾6个龄期的幼虫。4龄幼虫接种后48 h,虫体出现缩短、强直等形态变化;接种后72 h,幼虫死亡且体外形成菌丝层;接种后120 h,虫体被浅玫烟色的分生孢子覆盖。随孢子浓度的升高,幼虫的感病死亡率增加,当浓度达到1×109孢子/mL时,1~3龄幼虫的累计死亡率均为100%,4龄幼虫和5龄幼虫也达到了98.9%和50%,6龄幼虫仅21.1%。5 d后1~5龄幼虫的LC 50值分别为3.74×104、1.17×105、1.86×105、8.09×105和3.03×108孢子/mL。幼虫LT 50值随孢子浓度增加而递减,在浓度为1.0×105~1.0×109孢子/mL的范围内,1龄幼虫和2龄幼虫的LT 50值分别为3.62~1.37 d和4.51~1.65 d;在1.0×106~1.0×109孢子/mL时,对3龄幼虫的LT 50为4.03~1.82 d;浓度为1.0×107~1.0×109孢子/mL时,对4龄幼虫的LT 50为3.47~2.52 d。浓度为1.0×109孢子/mL时,5龄幼虫的LT 50为4.74 d。本研究结果表明,玫烟色虫草菌株IFCF01对草地贪夜蛾幼虫具有较强的致病力,为今后草地贪夜蛾微生物防治提供重要的有效真菌。     

马铃薯不同品种感染早疫病菌后防御酶活性变化

通过测定抗性不同的马铃薯品种接种和未接种情况下叶片内防御酶活性,研究马铃薯品种对早疫病的抗性机制。结果表明,在接种处理后,各品种植株体内苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、多酚氧化酶（PPO）和过氧化氢酶（CAT）活性均提高,抗病品种酶活性增幅高于感病品种,说明上述4种酶与品种抗性有一定的关联。     

长芒以礼草———青海禾本科一新种

对产自青海的以礼草属一新种———长芒以礼草( Kengyilia longiaristata) , 进行了描述。     

The Seed Plant Flora of Valley in Upper Reaches of Yellow River in East Qinghai,China

The valley in upper reaches of Yellow River is situated in the east of Qinghai, China, between latitude 35b20c~ 36b 25c N and longitude 100b55c~ 102b50c E. This area belongs to the transitional zone of Qingha-i Tibetan Plateau and Loess Plateau at an altitudinal range of 1 780m to 4 969 m. The total area is c113 480 km2. Its climate is continental or plateau- continental one. There are 1 027 species of wild seed plants which belong to 86 families and 404 genera in the area. They are 44195% of the total species, 95156% of the total families and 79153% of the total genera in Qinghai, respectively. The floristic characteristics in wild seed plants for the area are as follows: ( 1) Species and woody ones are richer. ( 2) Species endemic to China also richer, but those endemic to Qinghai are very poor. ( 3) On the level of genera, all the fifteen distribution types in China, especia-lly all the six tropical ones only occur in the area in Qinghai. ( 4) On the analysis of genera and species, the flora is temperate in nature which is dominated by North Temperate elements especially the typical elements from the warm and cold zone of Eurasia, and also with some elements of thewarm, cold warm and alpine types. ( 5) The area is of a marginal one in distribution for many species or genera and especially for many tropical ones, so the flora of the area is clear in maginal nature. ( 6) In floristic geography, it is a converged and transitional region for the Loess Plateau Flora, Hengduan Mountians Flora, Alpine Qingha-i Tibetan Plateau Flora, as well as Qaidam Alpine Desert Flora, so the flora of the area is also conspiarously a transitional one. Therefore, as a marginal region far from the center of Qingha-i Tibetan Plateau and with a transitional flora more or less keeping the floristic nature of plateau and alpine types, so the valley in upper reaches of Yellow River in Qinghai should be a flora still belonging to the Tangute one, although it is weaker in alpine nature but conspicuously much more related to North China one.     

利用宿主-载体平衡致死系统构建志贺氏菌3价疫苗候选株

选择福氏2a志贺氏菌疫苗株T32为受体菌,通过基因同源重组交换技术,对其染色体asd基因进行定位突变,使之不能在LB培基上生长;同时利用链球菌asd基因构建Asd⁺的无抗药性互补载体,两者组成1套T32宿主载体平衡致死系统.进一步应用该系统克隆和表达了具有重要免疫保护功能的宋内I相O抗原基因和志贺氏毒素B亚单位基因(stxB),构建成福氏2a-宋内-StxB3价菌苗候选株FSD0l.结果显示:该菌株遗传稳定,重组质粒不需用抗生素选择,能有效表达3价抗原和产生针对上述3种野生型毒株的免疫保护反应.     

巴颜喀拉山地区植物区系研究

巴颜喀拉山地区位于青海省南部 ,北纬 32°2 0′～ 35°15′ ,东经 94°5 0′～ 10 1°4 5′ ,面积约84 0 0 0km2 ,海拔高程介于 36 0 0m至 5 36 9m之间。本地区拥有种子植物 1116种 ,分属于 6 4科 ,2 95属。区系特征概述如下 :1)对属的分布区类型的分析表明 ,本地区植物区系以北温带成分为主 ,仅有 9个分布区从热带延伸到温带的热带属 ,且在本区所含种类极少或仅有 1种。 2 )对种的分布区类型的分析表明 ,大多数种 (不包括中国特有种 )属于中亚成分和东亚成分 ,且多呈中亚 -喜马拉雅 -中国西南或中国 -喜马拉雅分布式样。以此为据所得结论是 ,本地区的种以温带成分为优势 ,具高原、高山分布的特点。 3)本区东南部的生态环境和区系成分的来源均不同于其余地区。东亚分布型及其变型中国 -喜马拉雅的种聚集在东南部。这里被认为是那些来源于横断山和西秦岭的区系成分的一个通道。 4 )对中国特有种的分析表明 ,本区系与横断山区系和甘肃南部区系联系最为密切。 5 )在高山特化作用和高山生态因子的选择之下 ,本区植物获得了适应寒冷和干旱的特性。 6 )本区植物的耐寒性常常伴随着耐旱和耐湿的双重特性 ,植物的这些特性也反映在它们的地理分布上。 7)本区的区系性质和特点与唐古特地区基本一致 ,因此本植物区     

甘西鼠尾草一新变型

2004年8月份,我们在巴颜喀拉山南坡考察时,在四川省的壤塘县发现了甘西鼠尾草的一个白花变型,生境为海拔3350m的沟谷林缘灌丛,现报道如下。     

Oxalate decarboxylase from Agrobacterium tumefaciens C58 is translocated by a twin arginine translocation system

Oxalate decarboxylases (OXDCs) (E.C. 4.1.1.2) are enzymes catalyzing the conversion of oxalate to formate and CO The OXDCs found in fungi and bacteria belong to functionally diverse protein superfamily known as the cupins. Fungi-originated OXDCs are secretory enzymes. However, most bacterial OXDCs are localized in the cytosol, and may be involved in energy metabolism. In Agrobacterium tumefaciens C58, a locus for a putative oxalate decarboxylase is present. In the study reported here, an enzyme was overexpressed in Escherichia coli and showed oxalate carboxylase activity. Computational analysis revealed the A. tumefaciens C58 OXDC contains a signal peptide mediating translocation of the enzyme into the periplasm that was supported by expression of signal-peptideless and full-length versions of the enzyme in A. tumefaciens C58. Further site-directed mutagenesis experiment demonstrated that the A. tumefaciens C58 OXDC is most likely translocated by a twin-arginine translocation (TAT) system.     

Ribozymes against TGFbeta1 reverse character of activated hepatic stellate cells in vitro and inhibit liver fibrosis in rats

BACKGROUND/AIMS: Transforming growth factor beta (TGFbeta1) is considered the key mediator in the process of liver fibrosis. The purpose of this investigation was to evaluate the activity of ribozymes against TGFbeta1 in a cell-free system and activated hepatic stellate cells (HSCs), and antifibrotic effect in activated HSCs in vitro and in rats. METHODS: Three ribozymes targeting against TGFbeta1 mRNA were designed, and then cloned into the U1 snRNA expression cassette. The chimeric ribozymes were selected for the analysis of their performances in activated HSCs through the detection of their cleavage activities in a cell-free system. After ribozyme-encoding plasmids had been transfected into HSC-T6 cells, the effects of ribozymes on activated HSCs were evaluated through the analysis of proliferation, activation and collagen deposition of HSC-T6. The adenoviral vector expressing the ribozymes was constructed, and then delivered into rat models of hepatic fibrosis induced by carbon tetrachloride. RESULTS: TGFbeta1 expression was efficiently down-regulated in activated HSCs by U1 snRNA chimeric ribozymes which possessed perfect cleavage activity in a cell-free system. Further studies demonstrated that U1 snRNA chimeric ribozymes inhibited the synthesis of collagen I, reduced deposition of collagen I, suppressed BrdU incorporation, but had no effect on desmin and alpha-SMA expression in transfected HSC-T6 cells. Histological analysis demonstrated that the adenoviral vector expressing ribozyme (Rz803) could alleviate fibrotic pathology in rats treated with carbon tetrachloride. CONCLUSIONS: The anti-TGFbeta1 ribozymes could reverse the character of activated HSCs in vitro and improve fibrotic pathology in vivo. It indicated that TGFbeta1 could be considered as a novel candidate for a therapeutic agent against hepatic fibrosis.     

一种嗜热厌氧纤维素降解细菌的分离纯化方法*

根据纤维素降解细菌对不溶性纤维素底物的粘附作用,利用Hungate厌氧操作技术直接以不溶性纤维素粉为基质进行滚管,分离和纯化获得嗜热厌氧纤维素降解细菌。