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【目的】小毛瓢虫属Scymnus Kugelann昆虫主要捕食蚜虫、蚧虫等害虫,是一类经济上重要的天敌昆虫。目前针对小毛瓢虫属的系统发育研究尚属空白,亚属之间的系统演化关系尚不明确,为了建立合理的分类系统,亟需对小毛瓢虫属的亲缘关系进行研究和探讨。【方法】以华南农业大学馆藏的小毛瓢虫属5亚属共44种为研究对象,采用PCR技术对12S, 16S和28S rRNA基因的部分序列进行扩增;运用MEGA 7.0分析了小毛瓢虫属内12S, 16S和28S rRNA基因的碱基组成,基于K2P模型计算了小毛瓢虫属44种的种间遗传距离;采用最大似然法(maximum-likelihood, ML)和贝叶斯推断法(Bayesian-inference, BI)构建该属的系统发育树。【结果】扩增获得小毛瓢虫属44种的12S rRNA基因序列平均长度为356 bp, 16S rRNA基因序列平均长度为351 bp, 28S rRNA基因序列平均长度为315 bp;序列分析表明,12S rRNA基因的A, T, G和C平均含量分别为38.8%, 43.5%, 11.9%和5.8%, 16S rRNA基因的A, T, G和C平均含量分别为37.6%, 40.3%, 14.4%和7.7%, 28S rRNA基因的A, T, G和C平均含量分别为26.7%, 18.3%, 31.4%和23.5%;基于联合序列分析的种间遗传距离为0.004~0.276,平均遗传距离为0.115。系统发育分析结果表明,小毛瓢虫属为单系起源,而小毛瓢虫亚属Scymnus(Scymnus) Kugelann、毛瓢虫亚属Scymnus(Neopullus) Sasaji、小瓢虫亚属Scymnus(Pullus) Mulsant和拟小瓢虫亚属Scymnus(Parapullus) Yang均为并系起源。【结论】基于12S, 16S和28S rRNA基因序列的小毛瓢虫属系统发育分析显示传统的形态学分类体系与基于分子数据分析的结果部分不一致,这表明应该对该属内各亚属的鉴别特征进行全面检视,筛选并确立各亚属的形态指标,同时也表明该属内的亚属分类单元需重新厘定。 相似文献
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The aim of this study was to investigate the feasibility of using short tandem repeats (STRs) to diagnose Edwards’ syndrome (ES). Quantitative fluorescence polymerase chain reaction (QF-PCR) was performed to amplify STR loci on chromosome 18, specifically D18S53, D18S59, and D18S488. The amplified products were subjected to a fluorescence signal analysis and their application to ES diagnosis was examined. Among the 807 cases that showed normal results in the karyotype analysis, 793 showed one or two fluorescence bands with a fluorescence intensity ratio of 1:1, and 14 cases showed 3 bands, which were false-positive results. ES was diagnosed in 9 samples. The sensitivities of D18S53, D18S59, and D18S488 for the diagnosis of ES were 77.78, 44.44, and 55.56 % and the specificities were 96.16, 96.03, and 96.28 %, respectively. The combined sensitivity of the three loci for diagnosing DS was 100 % (9/9), with a specificity of 98.27 % (793/807). QF-PCR amplification of STR loci had high sensitivity, strong specificity, and was simple and rapid. Thus, it might have wide clinical applications, and could be an ideal tool for large-scale genetic and prenatal diagnosis of ES. 相似文献
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Summary The arrangement of centromeres, cluster formation and association with the nucleolus and the nuclear membrane were characterized in human lymphocytes during the course of interphase in a cell-phase-dependent manner. We evaluated 3 893 cell nuclei categorized by five parameters. The centromeres were visualized by means of indirect immunofluorescent labeling with anti-centromere antibodies (ACA) contained in serum of patients with CREST syndrome. The cell nuclei were classified as G0, G1, S, G2, Gl1 and early S phase by comparing microscopically identified groups of cell nuclei with flow cytometric determination of cell cycle stage of synchronized and unsynchronized lymphocyte cell cultures. Based on a discrimination analysis, a program was devised that calculated the probability for any cell nucleus belonging to the G0, G1, S, G2, G1 and early S phase using only two microscopic parameters. Various characteristics were determined in the G0, S, and G2 stages. A transition stage to S phase within G1 was detected. This stage shows centromere arrangements not repeated in later cell cycles and which develop from the dissolution of centromere clusters in the periphery of the nucleus during G0 and G1. S phase exhibits various non-random centromere arrangements and associations of centromeres with the nucleolus. G1 and early S phase of the second cell cycle display no characteristic centromere arrangement. The duplication of centromeres in G2 is asynchronous in two phases. For all cell phases a test for random distribution of the centromeres in the cell nucleus was performed. There is a distinct tendency for centromeres to be in a peripheral position during Go and G1; this tendency becomes weaker in S phase. Although the visual impression is a seemingly random distribution of centromeres in G2 and G1 statistical analysis still demonstrates a significant deviation from random distribution in favor of a peripheral location. Only the early S phase of the second cell cycle shows no significant deviation from a random distribution. 相似文献
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基于部分18S rDNA, 28S rDNA和COI基因序列的索科线虫亲缘关系 总被引:1,自引:0,他引:1
通过PCR扩增获得我国常见昆虫病原索科线虫6属10种18S rDNA、28S rDNA(D3区)和COI基因序列,结合来自GenBank中6属10种索科线虫的18S rDNA同源序列,用邻接法和最大简约法构建系统进化树。结果显示:12属索科线虫分为三大类群,第一大类群是三种罗索属线虫(Romanomermis)先聚在一起,再与两索属(Amphimermis)和蛛索属(Aranimermis)线虫聚为一支;在第二大类群中,六索属(Hexamermis)、卵索属线虫(Ovomermis)和多索属(Agamermis)亲缘关系最近,先聚在一起,再与八腱索属(Octomyomermis)和Thaumamermis线虫聚为一支。第三大类群由索属(Mermis)和异索属(Allomermis)线虫以显著水平的置信度先聚在一起,再与蠓索属(Heleidomermis)和施特克尔霍夫索属(Strelkovimermis)线虫聚为一支。从遗传距离看,基于3个基因的数据集均显示索科线虫属内种间差异明显小于属间差异,武昌罗索线虫(R.wuchangensis)和食蚊罗索线虫(R.culicivorax)同属蚊幼寄生罗索属线虫,其种间的遗传距离最小。 相似文献
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A total of 25 aphid species were collected from 49 ornamental plant species in S?o Carlos-S?o Paulo, Brazil; 12 aphids were monophagous, four oligophagous and nine polyphagous. A total of 58 aphid-plant associations are recorded, 43 unknown from Brazil. Eucarazzia elegans (Ferrari, 1872) (Aphididae: Aphidinae: Macrosiphini) is recorded for the first time from Brazil, and Nectandra megapotamica Spreng. (Lauraceae) is recorded for the first time as host plant for Lizerius tuberculatus (E.E. Blanchard, 1939) (Drepanosiphidae: Drepanosiphinae: Lizeriini). We also describe the injuries caused by aphids to the ornamental plants. 相似文献
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《Current opinion in plant biology》2000,3(3):169
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The aim of this work was to study the feeding process of Argyrodiaptomus furcatus (Copepoda-Calanoida) in the Lobo Reservoir (São Carlos, SP, Brazil). Non-ovigerous adult females and the 14C technique were used to measure filtration and assimilation rates. The diet contained the following phytoplankton species: Chlamydomonas sp., Ankistrodesmus gracilis, Melosira italica, Scenedesmus quadricauda and Chlorella zoofingensis.The experiments were carried out using unialgal and mixed cultures during 2-, 4- and 6-h periods. The results of the filtration and assimilation rates were compared.The data obtained by statistical tests showed the highest assimilation rate in Argyrodiaptomus furcatus fed Chlamydomonas sp. in both culture types. However, Chlorella zoofingensis and Scenedesmus quadricauda were the most filtered species in unialgal and mixed cultures, respectively. A higher filtration rate was observed for the 2-h period than for the 4- and 6-h periods.Culture agent was also important. Higher assimilation and filtration rates were obtained during the log phase of Chlamydomonas sp. growth than during the stationary phase. 相似文献
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A total of 283 Salmonella Typhimurium strains isolated from cases of human infections and non human sources, were examined for antimicrobial susceptibility and the incidence of resistance was 38% and multiple resistance (to three or more antimicrobials) was 15%. All 43 multidrug-resistant strains (MDR) and 13 susceptible ones were characterized by phage typing and pulsed- field gel electrophoresis (PFGE). The strains encompassed 14 definitive phage types (DT), three were untypable (UT), and 18 atypicals or reaction does not conform (RDNC), which belonged to 21 PFGE patterns, A1-A21. The predominant phage types were DT49, DT193, and RDNC and two strains belonging to DT 104 and 104b were also identified. The most common PFGE patterns were A1 and A8. Analysis by PFGE and phage typing demonstrated that the most of the MDR were multiclonal and association among multiresistance, phage typing, and PFGE patterns was not so significant. 相似文献
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新疆呼图壁种牛场地区优势植物K,Na,Ca,Mg,S的含量特征和数量分析 总被引:5,自引:0,他引:5
新疆呼图壁种子牛场地区草地25种植物中的K,Na,Ca,Mg,S在含量水平上Na>S>K>Mg>Ca。不同植物种类Na,S含量差异较大,如盐节木,囊果碱蓬等Na,S含量分别达100000ppm和30000ppm以上,而芦苇,獐茅草Na,S含量分虽在30000ppm和4000ppm以下;种间变异系数Na,S分别为95.10%,63.16%,K含量变异系数较小,为34.42%。同一种植物在不同地点Na 相似文献
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Six species of bioluminescent agarics are described and illustrated from a single site in primary Atlantic Forest habitat in the Parque Estadual Turistico do Alto Ribeira, Sao Paulo State, Brazil. These include two new taxa of Mycena, viz. M. asterina and M. lucentipes. Luminescence in Mycena fera, M. singeri and M. discobasis is reported for the first time. In addition an undeterminable luminescent Mycena species is described and additional specimens of Gerronema viridilucens are documented. An accounting of known bioluminescent species of Mycena and a discussion of why they luminesce are presented. 相似文献
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Faunal inventories are extremely important, especially when focused on neglected groups, such as echinoderms, and concentrated on areas under intense anthropic activity such as the SAo Sebastilo Channel in Brazil (23 degrees 41' - 23 degrees 54' S and 45 degrees 19' - 45 degrees 30' W). Intertidal and upper sublittoral zone collections were performed at five sites of the Channel's continental margin from May to August 2001. The rocky substrate down to 19 m deep was surveyed by snorkeling and SCUBA diving from August 2002 to May 2004, on both margins of the Channel: continental (14 sites) and insular (10 sites). We report a total of 38 species of echinoderms (one Crinoidea, nine Asteroidea, 13 Ophiuroidea, nine Echinoidea and six Holothuroidea). Seven of those species have been recorded here for the first time for the Channel (four Asteroidea, two Ophiuroidea and one Echinoidea). 相似文献