1000 resultados para 18S-29


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Objectives of the workshop included; introduction to various Marine Protected Area (MPA) tools with a focus on Management Effectiveness Assessment Tool (MEAT); report on selected MPAs in Bangladesh; undertake initial assessments using MEAT; and develop workplans for other MPAs

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The main objective of the visit was to share the success of Marine Protected Area (MPA) management in Malaysia with Bangladeshi counterparts, representatives of donor organizations, NGOs and researchers.

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中国科学院知识创新项目(KZCX2-YW-426); 国家自然科学基金重大项目(30490232)

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盾腹亚纲吸虫被认为是寄生扁形动物中古老的类群,包括盾腹科、多萼科、裂杯科和皱腹科,科间系统发育关系尚存争议。本研究收集GenBank数据库中所有的盾腹吸虫18S rRNA基因序列,测定了三种盾腹吸虫的相应序列,分别采用最大简约法和最大似然法构建分子系统发育树。结果显示,多萼科的分类地位不成立,多萼属应还原到盾腹科;盾腹科的盾腹亚科和杯盾亚科均非单系,吸槽列数可能是平行进化特征,不能反映盾腹科各亚科间的系统发育关系。建议将具有边缘器的吸槽型腹吸盘,以及不具边缘器的吸杯型和皱褶型腹吸盘分别鉴定为盾腹科、裂杯科

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为了探讨鱼类寄生嗜子宫线虫的系统发育关系,测定了8种嗜子宫线虫的ITS rDNA(核糖体转录内间隔区核 糖核酸)序列和9种嗜子宫线虫的18S rDNA(小亚基核糖体核糖核酸)部分序列,并构建了18S rDNA序列的系统发 育树。在比较和分析ITS rDNA和18S rDNA两种分子标记对嗜子宫科线虫系统发育适用性的基础上,分析了嗜子 宫线虫的系统发育关系。结果表明:中国嗜子宫线虫是单系起源;黄颡鱼似嗜子宫线虫、赣州似嗜子宫线虫和棍头 嗜子宫线虫亲缘关系非常接近,可能是较晚形成的种;似嗜子宫线虫属可能应该被

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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

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建立了由采自自然界中的样品、不经实验室培养而直接用于大核DNA提取和PCR反应的原位(in situ)方法;在此基础上,测定并比较了6种累枝虫(Epistylis wenrichi,E.urceolata,E.chrysemydis,E.plicatilis,E.hentscheli,E.galea)的18S-ITS1序列,结果显示:E.wenrichi,E.urceolata,E.chrysemydis,E.plicatilis和E.hentscheli间18S和ITS1区序列的碱基相似性很高,而它们与

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记述了在中国6个典型地带土壤中鉴定到的隶属于动基片纲的29种纤毛虫,其中5种为中国土壤原生动物新记录种.这些种类是:陆生拟裸口虫,恼斜板虫,吻瓶口虫,双核管形虫,琴刀口虫,长刀口虫,长尾刀口虫,斜叶苔叶虫,神螺流苏虫,土壤肾形虫,三分肾形虫,背沟肾形虫,无规肾形虫,直立肾形虫,粗糙拟肾形虫,莫氏拟肾形虫,贪食阔庭虫,大撕拉虫,吻吴氏虫,澳洲吴氏虫,大口匙口虫,尖锐密粒虫,卡氏颠毛虫,小拟匙口虫,尖锐篮环虫,丛林拟篮环虫,有肋薄咽虫,弧形微秀体虫和凤冠齿扇虫.

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The phylogenetic relationships among the Ergasilidae genera are poorly understood. In this study, 14 species from four genera in the Ergasilidae including Sinergasilus, Ergasilus, Pseudergasilus, and Paraergasilus were collected in China, and their phylogenetic relationships were examined using neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian inference methods based on partial sequences of 18S and 28S ribosomal deoxyribonucleic acid, respectively. All the analyses suggest that the Sinergasilus and Paraergasilus are both monophyletic, but the Ergasilus is polyphyletic rather than monophyletic. Considering the relationships among the four genera, the phylogenetic analyses and subsequent hypothesis tests all suggest that Pseudergasilus clustered with some Ergasilus species may have a closer relationship with Sinergasilus rather than with Paraergasilus. It is proposed that the Sinergasilus and the Pseudergasilus species might have evolved from Ergasilus species.

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A comparative limnological study was carried out to present a snapshot of crustacean zooplankton communities and their relations to environmental factors to test whether there is a consistent relationship between crustacean biomass and trophic indicators among lake groups with similar trophic conditions. The study lakes showed a wide range of trophic status, with total phosphorus (TP) ranging from 0.008 to 1.448mgL(-1), and chlorophyll a from 0.7 to 146.1 mu g L-1, respectively. About 38 species of Crustacea were found, of which Cladocera were represented by 25 taxa (20 genera), and Copepoda by 13 taxa (I I genera). The most common and dominant species were Bosmina coregoni, Moina micrura, Diaphanosoma brachyurum, Cyclops vicinus, Thermocyclops taihokuensis, Mesocyclops notius and Sinocalanus dorrii. Daphnia was rare in abundance. Canonical correspondence analysis showed that except for four species (D. hyalina, S. dorrii, C. vicinus and M. micrura), almost all the dominant species had the same preference for environmental factors. Temperature, predatory cyclopoids and planktivorous fishes seem to be the key factors determining species distribution. TP was a relatively better trophic indicator than chlorophyll a to predict crustacean biomass. Within the three groups of lakes, however, there was no consistent relationship between crustacean biomass and trophic indicators. The possible reason might be that top-down and bottom-up control on crustaceans vary with lake trophic state. The lack of significant negative correlation between crustacean biomass and chlorophyll a suggests that there was little control of phytoplankton biomass by macrozooplankton in these shallow subtropical lakes. (c) 2007 Elsevier GmbH. All rights reserved.

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The phylogeny of Oedogoniales was investigated by using nuclear 18S rDNA sequences. Results showed that the genus Oedocladium, as a separated clade, was clustered within the clade of Oedogonium; whereas the genus Bulbochaete was in a comparatively divergent position to the other two genera. The relationship among the species of Oedogonium was discussed, focusing on ITS-2 phylogeny analyzed combining with some morphological characteristics. Our results showed that all the dioecious nannandrous taxa involved in this study were resolved into one clade, while all the monocious taxa were clustered into another clade as a sister group to the former. The report also suggests that the dioecious macrandrous taxa form a paraphyly and could be more basally situated than the dioecious nannandrous and the monoecious taxa by means of molecular phylogeny and morphotype investigations.

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Based on the variation of site 34, 46, 241, 305 and 322 in the 18S-ITS1 rDNA sequence, 19 Carchesium polypinum populations collected from eight provinces of China were separated into northern and southern population along the delineation between the Yangtze River and the Pearl River. This geographic distribution pattern of Carchesium polypinum maybe results from two factors: the vicariance resulting from the formation of the delineation between the Pearl River and the Yangtze River accompanied with the uplift of Qinghai-Xizang Plateau, and the different dispersal paths of C. polypinum affected by the climate.

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Phylogenetic relationships among six species of Epistylis (i.e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E, galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E, hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.

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We demonstrate 1.25-1.29 mu m metamorphic laser diodes grown on GaAs by molecular beam epitaxy (MBE) using an alloy-graded buffer layer (GBL). Use of Be in the GBL is effective to reduce surface/interface roughness and improves optical quality. The RMS surface roughness of the optimized metamorphic laser is only two atomic monolayers for 1 x 1 mu m(2). Cross-sectional transmission electron microscopy (TEM) images confirm that most dislocations are blocked in the GBL. Ridge waveguide lasers with 4 mu m wide ridge were fabricated and characterized. The average threshold current under the pulsed excitation is in 170-200 mA for a cavity length of 0.9-1.5 mm. This value can be further reduced to about 100 mA by high-reflectivity coating. Lasers can work in an ambient temperature up to at least 50 degrees C. (c) 2006 Elsevier B.V. All rights reserved.