大麦杆在控制水华藻类中的应用

科技部和云南省资助项目k99 0 5 3 5 0 1 ; 青藏高原及其邻近地区植物区系及分布格局研究 (KSCX2 1 0 6B)资助

噬菌体展示技术的原理和方法

中国科学院择优特别支持费 [Stz98-3-0 5 ]; 国家自然科学基金 [30 0 5 0 0 0 3H];[30 1 70 72 7]资助

单苯环氯取代指数法预测二噁类化合物PCDDs的正辛醇/水分配系数

采用单苯环氯取代指数作为氯代二苯并二口恶口英类化合物 (PCDDs)的分子结构描述符 ,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比 ,该模型不仅具有显著的相关性 (n =43,Radj=0 898,SE =0 195 ,在α =0 0 5时 ,F =2 0 45 5 ,p =0 0 0 0 0 ) ,而且对于分子结构具有更好的区分能力。利用建立的模型 ,对没有logKow文献值的其他 33种PCDDs化合物给出了预测值

蓝藻Anabaena sp.PCC7120 羧体碳酸酐酶的鉴定

在丝状蓝藻Anabaena sp.PCC7120细胞粗提液的碳酸酐酶(CA)分析中,发现了两种形式的CA活性.高CO_2下生长的细胞,在35μmol/L EZ(Ethoxyzolamide,碳酸酐酶的抑制剂)存在的情况下,CA总活性的85％左右被抑制,其半抑制浓度I_(50)为7.4μmol/L;随着EZ浓度的继续增加,CA活性在EZ浓度达到约150μmol/L处出现了第二个抑制峰,在250μmol/L处抑制程度达到最大,使CA总活性的15％被抑制,其半抑制浓度I_(50)为190μmol/L。在空气条件

鱼类生产力研究的方法与进展

国家自然科学基金(湖泊食鱼性鱼类生产潜力估算方法的研究 );396 70 575号;中国科学院资源与生态环境局资助(长江中下游浅水湖群比较?

蓝藻Anabaenasp.strainPCC7120中一种可诱导的CO_2浓缩机制(CCM)

为了探讨蓝藻Anabaenasp .strainPCC71 2 0在外源无机碳浓度变化时 ,其光合作用对CO2 和HCO-3 的利用特性 ,制备了高CO2 适应细胞 (High CO2 growingcells ,HCG细胞 ) .Anabaenasp .strainPCC71 2 0HCG细胞的生长速率高于LCG细胞 (Low CO2 GrowingCells) ,即在空气中生长的细胞 .当HCG细胞从 5 %CO2 转移到空气中时 ,其碳酸酐酶活性升高 ;它对外源无机碳的表观光合作用亲合力明显提高 ,

应用逆转录聚合酶链反应直接检测草鱼出血病病鱼组织的研究

人工感染GCHV－861后，对处于潜伏期、发病期和恢复期等不同时期的草鱼内脏组织匀浆上清液进行逆转录聚合酶链式反应（RT－PCR）扩增，除恢复期的1条草鱼外，其余样品均得到特异扩增带，而对照组都没有，预示着RT－RCR技术对于草鱼出血病的早期诊断、防治及抗病有种具有重要意义。另外，对于显症出血病草鱼的肝、肾、脾、鳃、肌肉和肠道等组织器官进行检测，结果都为阳性，首次证实了GCHV存在于肝脏中，并对此作了进一步的讨论。

用逆转录聚合酶链式反应检测草鱼出血病病毒的研究

于1994年5月-1995年7月，根据已克隆的草鱼出血病病毒GCHV-861株cDNA的部分序列，设计合成了两对PCR引物，采用RT-PCR技术对GCHV-861及GCHV-873两病毒株的dsRNA进行扩增。结果表明，两对引物仅能特异地检测出GCHV-861病毒株核酸的存在，而不能对GCHV-873病毒株的核酸进行特异扩增，该方法最小可检测出0.1Pg纯化的GCHV-861病毒dsRNA;采用该方法对GCHV-861人工感染的草鱼和稀有鲫组织进行RT-PCR检测，不仅能检测到发病期显症病鱼中GCHV-8

罗非鱼对微型生态系统营养物水平的影响

本文总结了罗非鱼不同放养密度的微型生态系统中N、P浓度及P分布动态观测结果。在罗非鱼的影响下,微型生态系统中氨氮、颗粒磷和总磷浓度不同程度地高于对照组,而正磷酸盐浓度和沉积物磷的量显著地低于对照组。不同密度组某些指标的观测值虽有显著差异,但未见任何指标依罗非鱼放养密度而有规律地变动。微型生态系统中正磷酸盐浓度同浮游动、植物密度和初级生产力显著相关,氨氮浓度与浮游植物密度之间亦有显著的相关关系。然而,浮游植物密度与总磷浓度之间不存在营养级联假说所预见的下行影响,相反有前者决定于后者的上行影响的趋向。微型生态

Studies on temporal and spatial variations of phytoplankton in Lake Chaohu

Temporal and spatial variations of the phytoplankton assemblage in Lake Chaohu, a large shallow eutrophic lake in China, were studied from September 2002 to August 2003. A total of 191 phytoplankton species was identified, among which Chlorophytes (101) ranked the first, followed by Cyanophytes (46) and Bacillariophytes (28). On average over the entire lake, the maximum total algal biomass appeared in June (19.70 mg/L) with a minimum (5.05 mg/ L) in November. In terms of annual mean biomass, cyanobacteria contributed 45.43% to total algal biomass, followed by Chlorophytes (27.14%), and Bacillariophytes (20.6%). When nitrate (NO3-N) and ammonium (NH4-N) concentrations dropped in spring, fixing-nitrogen cyanobacterium (Anabaena) developed quickly and ranked the first in terms of biomass in summer. It is likely that dominance of zooplanktivorous fish and small crustacean zooplankton favored the development of the inedible filamentous or colony forming cyanobacteria. The persistent dominance of cyanobacteria throughout all seasons may indicate a new tendency of the response of phytoplankton to eutrophication in Lake Chaohu.

Age and growth of an endemic cyprinid fish, Spinibarbus yunnanensis, from Lake Fuxian, China

Age and growth of Spinibarbus yunnanensis Tsu in Lake Fuxian were investigated by examination of annuli from scales, dorsal fin spines, and otoliths. Sectioned otoliths exhibited the clearest and the most regular annuli. The formation of false annuli, which regularly arose on scales and dorsal fin spines during the juvenile stage, may be caused by a change in diet during development. The parameters for the von Bertalanffy growth curve were: K = 0.105, L-infinity = 950 mm, t(0) = -0.22 year for both sexes. W-infinity, calculated from the relationship W-infinity = aL(infinity)(b), was 10,352 g.

Life history and production of Sphaerium lacustre (Mollusca : Sphaeriidae) in a shallow subtropical Chinese lake

A fingernail clam, Sphaerium lacustre, was studied in subtropical Lake Donghu from June 1999 to May 2000. The S. lacustre population was characterized by a single annual reproduction period starting in March and ending in October; the population comprised three size groups, of which the 1999 cohort was dominant. The annual average density and biomass were 100.2 ind./m(2) and 12.11 g/m(2), respectively The annual production was 43.02 wet weight g/m(2), and the corresponding annual production/biomass ratio was 3.55.

Genome segment S8 of grass carp hemorrhage virus encodes a virion protein

The complete nucleotide sequence of the genome segment S8 of grass carp hemorrhage virus (GCHV) was determined from cDNA corresponding to the viral genomic RNA. It is 1,287 nucleotides in length and contains a large open reading frame that could encode a protein of 409 amino acids with a predicted molecular mass of 44 kD. The S8 was expressed using the pET fusion protein vector and detected by Western blotting analysis using the chicken egg IgY against intact GCHV particles, indicating that S8 encodes a virion protein. Amino acid sequence comparisons revealed that the protein encoded by S8 is closely related to protein alpha2 of mammalian reovirus, suggesting that the deduced protein of S8 is an inner capsid protein. Copyright (C) 2001 S. Karger AG, Basel.

A detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription polymerase chain reaction

A rapid, sensitive and highly specific detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription-polymerase chain reaction (RT-PCR) has been developed. Two pairs of PCR primers were synthesized according to the cloned cDNA sequences of the GCHV-861 strain. For each primer combination, only one specific major product was obtained when amplification was performed by using the genomic dsRNA of GCHV-861 strain. The lengths of their expected products were 320 and 223 bp, respectively. No products were obtained when nucleic acids other than GCHV-861 genomic RNA were used as RT-PCR templates. To assess the sensitivity of the method, dilutions of purified GCHV-861 dsRNA total genome (0.01 pg up to 1000 pg) were amplified and quantities of as little as 0.1 pg of purified dsRNA were detectable when the amplification product was analyzed by 1.5% agarose gel electrophoresis. This technique could detect GCHV-861 not only in infected cell culture fluids, but also in infected grass carp Ctenopharyngodon idellus and rare minnow Gobiocypris rarus with or without hemorrhagic symptoms. The results show that the RT-PCR amplification method is useful for the direct detection of GCHV.

Fabrication and Characterization of High Power InGaN Blue-Violet Lasers with an Array Structure

InGaN/GaN multi-quantum-well-structure laser diodes with an array structure are successfully fabricated on sapphire substrates. The laser diode consists of four emitter stripes which share common electrodes on one laser chip. An 800-mu m-long cavity is formed by cleaving the substrate along the < 1 (1) over bar 00 >. orientation using laser scriber. The threshold current and voltage of the laser array diode are 2A and 10.5 V, respectively. A light output peak power of 12W under pulsed current injection at room temperature is achieved. We simulate the electric properties of GaN based laser diode in a co-planar structure and the results show that minimizing the difference of distances between the different ridges and the n-electrode and increasing the electrical conductivity of the n-type GaN are two effective ways to improve the uniformity of carrier distribution in emitter stripes. Two pairs of emitters on a chip are arranged to be located near the two n-electrode pads on the left and right sides, and the four stripe emitters can laser together. The laser diode shows two sharp peaks of light output at 408 and 409 nm above the threshold current. The full widths at half maximum for the parallel and perpendicular far field patterns are 8 degrees and 32 degrees, respectively.