淡水鱼类粘孢子虫的18S rDNA分子系统学研究

利用两个通用引物myxoF(5′ CGCGGTAATTCCAGCTCCAGTAG 3′)和myxoR(5′ ACCAGGTAAGTTTTCCCGTGTTGA 3′)成功扩增出圆形碘泡虫、全圆碘泡虫、武汉单极虫、微山尾孢虫和库班碘泡虫 5种粘孢子虫的部分 18SrDNA序列 ,其GenBank登录号为 :AY16 5 179—AY16 5 183。并结合GenBank其他 13个相关序列构建了 18个物种的分子系统树。结果表明 ,碘泡虫 ,尾孢虫和单极虫较Tetracapsulabryozoides和“PK

草鱼出血病病毒873株基因组外发现缺损性干扰颗粒的亚基因组成份

草鱼出血病病毒基因组由 11条dsRNA片段组成。最近在研究其基因组时发现 ,在病毒基因组外存在许多核酸成份 ,但在核苷酸数量上少于基因组成份 ,表现为较小分子量的RNA片段。在完整地克隆了这些片段的全长cDNA后 ,测定了其中两个克隆的序列组成 ,发现它们为病毒基因组经剪切后的部分片段 ,已经重新装配 ,而且都含有原基因组某一片段 3′端和 5′端的保守区和倒转重复区 ,缺失中间部分。根据其特点来看 ,它们应为目前病毒学研究的重要材料———缺损性干扰颗粒的亚基因组成份。

螅状独缩虫表膜下纤毛系及形态发生

利用蛋白银技术研究了螅状独缩虫无性生殖周期中的形态发生。结果表明 :(1)在大核形态尚未出现明显变化时 ,生发毛基索 (GK)的前端即出现原基 ,随后原基增生扩大。最早出现的是两条将来分别演化为新仔虫第三咽膜 (P′3)和第二咽膜 (P′2 )的原基带 ,随后出现的是位于外侧的新仔虫的单毛基索 (HK′)。同时 ,新仔虫的第一咽膜 (P′1)也开始由老单毛基索 (HK)复制 ,并在细胞分裂后期与老结构分离 ;(2 )大核在虫体分裂过程中由长带状逐渐缩短变粗至扁圆形 ,于虫体即将分开时迅速拉长 ,然后分裂为

南极科学考察概况及淡水生态系统研究

本文简要介绍了南极洲的漂移演变、地理景观、气候状况和自然资源。对南极发现过程及科学考察历史亦作了简短论述。中国南极长城站位于西南极菲尔德斯半岛西南端 (58°57′52″W ,6 2°12′59″E) ,中山站则位于东南极拉斯曼丘陵的米勒半岛北端 (76°2 2′2 4″E ,6 9°2 2′2 4″S) ,两者相距 50 0 0km。作者以1991- 1995年实地考察结果为据 ,对长城站和中山站地区湖泊、溪流、雪地等淡水生态系统的理化环境、生物群落结构与功能现状进行比较研究 ,对引起两地淡水生态系统出

中国小鲃属的分类整理及小鲃属的分类学讨论(鲤形目:鲤科:鲃亚亚科)

ｕｎｔｉｕｓ是典型的热带和亚热带鱼类类群,主要生活在山涧溪流及敞水环境。Ｈａｍｉｌｔｏｎ(1822)建立此分类单元时将它作为Ｃｙｐｒｉｎｕｓ属的一个亚属。Ｂｌｅｅｋｅｒ(1863)用ＰｕｎｔｉｕｓＨａｍｉｌｔｏｎ属名代替ＳｙｓｔｏｍｕｓＭｃ′Ｃｌｅｌｌａｎｄ,确立...

褶累枝虫16S rRNA基因分析

以缘毛目褶累枝虫为研究材料，探索和建立了适用于较难培养的单细胞原生动物的分子生物学研究方法．并测定了褶累枝虫１６ＳｒＲＮＡ基因３′端１１１５个核苷酸．通过比较分析，从分子水平探讨了累枝虫属与缘毛目其它属之间的亲缘关系，为进一步重构原生动物的系统图提供最基本的资料．

An in computo investigation of the Landau-Kleffner syndrome

We describe a computational model of the thalamus and the cortex able to reproduce some essential epileptiform features commonly observed in the Landau-Kleffner syndrome. Investigation with this realistic model leads us to the formulation of a cellular mechanism that could be responsible for the epileptic discharges occuring with this severe syndrome. Understanding this mechanism is of prime importance for developing new therapeutical strategies. © 2007 IEEE.

天然雌核发育银鲫与两性生殖彩鲫卵母细胞中蛋白激酶基因表达差异的比较

采用mRNA差异显示方法 ,以蛋白激酶基因家族保守区设计 5′引物 ,比较天然雌核发育银鲫和两性生殖彩鲫卵母细胞中蛋白激酶基因的表达 .结果表明 ,以引物T12 MA ,T12 MC和T12 MG合成的cDNA第 1链分别再经蛋白激酶特异引物扩增所得到的PCR条带数目和分布模式各不相同 .从胶上总共回收并克隆了 2 1个cDNA片段 ,对其中 3个做了Northern杂交验证 ,有 2个在彩鲫卵母细胞中特异表达 ,另 1个在银鲫中特异表达 .

Ultralow surface recombination velocity in InP nanowires probed by terahertz spectroscopy.

Using transient terahertz photoconductivity measurements, we have made noncontact, room temperature measurements of the ultrafast charge carrier dynamics in InP nanowires. InP nanowires exhibited a very long photoconductivity lifetime of over 1 ns, and carrier lifetimes were remarkably insensitive to surface states despite the large nanowire surface area-to-volume ratio. An exceptionally low surface recombination velocity (170 cm/s) was recorded at room temperature. These results suggest that InP nanowires are prime candidates for optoelectronic devices, particularly photovoltaic devices, without the need for surface passivation. We found that the carrier mobility is not limited by nanowire diameter but is strongly limited by the presence of planar crystallographic defects such as stacking faults in these predominantly wurtzite nanowires. These findings show the great potential of very narrow InP nanowires for electronic devices but indicate that improvements in the crystallographic uniformity of InP nanowires will be critical for future nanowire device engineering.

综合生物塘中的藻类研究Ⅱ

治理城镇污水的综合生物塘中试运转三年中，共发现藻类１０２种。绿藻种类最多（占５５％）。全塘年均藻类细胞密度为１８．４×１０′个／１，现存生物量为３２．７ｍｇ／ｌ（鲜重），两者峰值均出现在四、五月。每年多数时间内以绿藻（主要是小球藻）为数量优势种类，生物量常以隐藻占优势。利用水生维管植物对出水进行生态修饰，能明显抑制藻类生长和改善出水水质。发现藻类在藻菌塘中的明显分层现象。

淡水鱼类寄生线虫三未定种

本文报道在湖北省武汉市(30°30′N,114°12′E)采到的嗜子宫科线虫三个未定种:嗜子宫线虫未定种1,寄生于乌鳢的肾;嗜子宫线虫未定种2,寄生于黄鳝的腹腔;布氏线虫未定种,寄生于蒙古红鲌的腹腔。后两种因只采到雌虫且不完全成熟而不宜鉴定种名。三未定种在国内均未曾有文献报道,本文给出了它们的简单描述、形态图和简单讨论,供进一步研究参考。

Stiffness of clays and silts: Normalizing shear modulus and shear strain

An analysis is presented of a database of 67 tests on 21 clays and silts of undrained shear stress-strain data of fine-grained soils. Normalizations of secant G in terms of initial mean effective stress p9 (i.e., G=p9 versus log g) or undrained shear strength cu (i.e., G=cu versus log g) are shown to be much less successful in reducing the scatter between different clays than the approach that uses the maximum shear modulus,Gmax, a technique still not universally adopted by geotechnical researchers and constitutive modelers. Analysis of semiempirical expressions forGmax is presented and a simple expression that uses only a void-ratio function and a confining-stress function is proposed. This is shown to be superior to a Hardin-style equation, and the void ratio function is demonstrated as an alternative to an overconsolidation ratio (OCR) function. To derive correlations that offer reliable estimates of secant stiffness at any required magnitude of working strain, secant shear modulus G is normalized with respect to its small-strain value Gmax, and shear strain g is normalized with respect to a reference strain gref at which this stiffness has halved. The data are corrected to two standard strain rates to reduce the discrepancy between data obtained from static and cyclic testing. The reference strain gref is approximated as a function of the plasticity index.Aunique normalized shear modulus reduction curve in the shape of a modified hyperbola is fitted to all the available data up to shear strains of the order of 1%. As a result, good estimates can be made of the modulus reduction G/Gmax ±30% across all strain levels in approximately 90% of the cases studied. New design charts are proposed to update the commonly used design curves. © 2013 American Society of Civil Engineers.

南极鱼两种寄生海蛭的研究

从南极海纽喀姆湾(南纬66°17′,东经110°32′)的南极鱼属Notothenia鱼体上得到两个海蛭标本。经鉴定为多皱海蛭Pontobdella rugosa Moore,1938和椎蛭属Notobdella的一新种。前者的环带后区环的分割明显并因许多大、小结节变得崎岖不平。在一完全体节(ⅫⅠ-ⅩⅫⅠ)里环的通常大小关系是8_2(?)a_1>b_5=b_(60)扭椎蛭新种Notobdella streptocheles sp.nov.呈S形弯曲井从稍膨大的中部向两端渐渐变细。在前吸盘上没有眼。尾吸盘与

梁子湖湖沼学资料

<正> 梁子湖是湖北省境内的大型湖泊之一。本所鱼类学组曾选择它来作为研究鱼类生物学的场所(1955—1957)。同时,为了了解与鱼类生活活动有关的若干环境因素,我们也对梁子湖区的周围环境和自然条件以及湖水和湖泥的各种性质等进行了调查。一、调查概况1955年2月,我们就在湖中央的一个小岛——梁子镇——上设立了工作站(镇位于东经114°33&prime;34&Prime;,北纬30°15&prime;18&Prime;)。在岛的东面湖滨设置了水文气象的观测点,每日有专人测定并记录气温、水温、日照时间、水位、风向与天气的情况等。此外,并从东沟水文

Diassociativity in Conjugacy Closed Loops

Let Q be a conjugacy closed loop, and N(Q) its nucleus. Then Z(N(Q)) contains all associators of elements of Q. If in addition Q is diassociative (i.e., an extra loop), then all these associators have order 2. If Q is power-associative and |Q| is finite and relatively prime to 6, then Q is a group. If Q is a finite non-associative extra loop, then 16 ∣ |Q|.