利用RAPD技术对海洋纤毛虫,弗州拟尾丝虫四种群的研究

利用筛选的4个引物S2009、S2010、S103以及S2008对采自青岛附近养殖水体的弗州拟尾丝虫（Parauronema virginianum）4个种群进行了随机制扩增多态DNA（RAPD）研究，所得清晰条带显示所研究的种群间存在一定的变异，其遗传距离在0.18-0.35之间，而与同属异种的外类群长拟尾丝虫（P.Longum)遗传距离可达0.76-0.83。利用上述数据构建了分子系统树并探讨了4个种群相互间的遗传距离，结果表明，实验所涉4种群之遗传关系无明显地域及采集时间差异。     

Electrochemical study of the interaction between Eu and ciliate Euplotes octocarinatus centrin

A new species was formed when protein P₂₃ (one segment of ciliate Euplotes octocarinatus centrin) was added to a solution of Eu³⁺. The interaction between P₂₃ and Eu³⁺ was investigated by cyclic voltammetry, pulse voltammetry and electrochemical impedance spectroscopy in 10 mM N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (HEPES) buffer (pH 7.4) using a pyrolytic graphite electrode. The formal potential (E^o′) of Eu³⁺ shifted from −0.61 to −0.84 V (versus saturated calomel electrode) after P₂₃ was added to the Eu³⁺ solution. The diffusion coefficient (D), the charge-transfer coefficient (α) and the electron transfer standard rate constant (k_s) were obtained in the absence and the presence of P₂₃. The affinity constant of Eu³⁺ and P₂₃ was determined to be (1.89 ± 0.51) × 10⁴ M⁻¹. The electrochemical investigation of europium bound to the protein provided useful data for the studies of calcium-binding proteins.     

胖尾刺虫 (纤毛门,旋毛纲,下毛目)16s小亚基单位核糖体RNA基因的序列测定及其系统地位初探

对分离自青岛沿岸的下毛目纤毛虫-胖尾刺虫(Uronychia transfuga)的16s小亚基单位核糖体RNA(16s-like Small Subunit rRNA)基因进行了序列测定,通过与目内其它相近属多种纤毛虫的比较分析,认为游仆虫属(Euplotes)首先从下毛目中分离出来,其次是属刺虫属和双眉虫属(Diophrys),其间邻近的遗传距离共同构成了下毛目内最为进化的类群-游仆亚目(Euplotina).同时,序列分析也支持该目其它三个亚目的划分散毛亚目(Sporadortrichina),排毛亚目(Stichotrichina)和尾柱亚目(Urostylina).这与形态学资料是吻合的.     

遗传密码子的通用性与特殊性

遗传密码子的通用性与特殊性是生物多样性的重要分子基础。本文就目前研究较多的热点密码子在线粒体和原生动物纤毛虫中的特殊性进行总结,并对其形成理论机制进行探讨,阐明变异密码子在线粒体中是通用密码子在漫长进化过程中的遗物,但在纤毛虫中则并非单一地由某个时间或从某个种类开始,而是独立多次地在各物种内分别产生。     

Community dynamics and significance of anaerobic protozoa during biomethanation of lignocellulosic waste

The diversity and community dynamics of anaerobic protozoa and their functional role during anaerobic digestion of a typical lignocellulose biomass in a lab scale leach bed coupled UASB reactor is reported in this study. The functional role played by different protozoa during various stages of methanogenesis was analyzed through linear regression analysis of individual protozoon counts with major hydrolytic enzyme activities, volatile fatty acid levels and biogas production. The protozoa community in the digester was represented by ciliates (Metopus, Cyclidium and Colpoda) and flagellates (Rhyncomonas, Menoidium and Bodo). Regression analysis revealed the relationship between total protozoa counts with the activity of cellulase (R² = 0.71) pectinase (R² = 0.50) amylase (R² = 0.53) and xylanase (R² = 0.34), total volatile fatty acid levels (R² = 0.86) and biogas production (R² = 0.78) in the digester. Moreover, it was found that both volatile fatty acid and biogas production is correlated with ciliate and flagellate populations. This study underlines the importance of both ciliates and flagellates in the anaerobic digestion process and, more specifically, the contribution by individual protozoa on hydrolysis, which is the rate limiting stage in anaerobic digestion.