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Primers to block the amplification of symbiotic apostome ciliate 18S rRNA gene in a PCR-based copepod diet study 总被引：1，自引：0，他引：1
Pelagic copepods play an important role in the marine food web. However, a full understanding of the ecological status of this zooplankton group depends on the careful study of their natural diets. In previous PCR-based copepod diet studies, we found many apostome ciliates that live symbiotically under the exoskeleton of the copepods, and their sequences were often over-represented in the 18S rRNA gene （18S rDNA） libraries. As a first step to address this issue, we designed three apostome ciliate 18S rDNA blocking primers, and tested their blocking efficiency against apostome ciliate 18S rDNA under various PCR conditions. Using a semi-quantitative PCR method, we optimized the conditions to efficiently amplify the 18S rDNA of the prey while simultaneously excluding the symbiotic apostome ciliates. This technique will facilitate PCR-based diet studies of copepods and other zooplankton in their natural environments. 相似文献
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桡足类是海洋生态系统中初级生产者和较高营养级消费者之间的关键联系环节,掌握桡足类的现场食物组成对于准确评估海洋食物网中的营养关系和能量转移至关重要。本研究中,我们以中华哲水蚤这一在中国、日本以及韩国近海具有重要生态地位的大型哲水蚤属桡足类为研究对象,应用之前开发的基于PCR的克隆技术,通过分析中华哲水蚤所摄食生物的18S rDNA序列,研究了中华哲水蚤的现场食物组成。结果揭示了南黄海（Y19站位）和渤海（B49站位）中华哲水蚤食物组成的多样性。共检测出43个操作分类单元（OTUs）,分别隶属于13个类群：硅藻（Bacillariophyta）、甲藻（Dinoflagellata）、硅鞭藻（Dictyochophyceae）、金藻（Chrysophyta）、Katablepharidophyta、浮生藻（Pelagophyceae）、无根虫（Apusozoa）、水螅水母（Hydrozoa）、栉水母（Ctenophora）、棘皮动物（Echinodermata）、被囊动物（Tunicata）、毛颚动物（Chaetognatha）以及海洋真菌。结果还表明,当发生藻类暴发时,中华哲水蚤可以摄食引发藻类暴发的藻种。当周围海域浮游植物的丰度相对较低时,中华哲水蚤可以选择摄食各种后生动物尤其是水螅水母和栉水母的卵、幼虫或者有机碎屑。我们的研究结果表明中华哲水蚤是一种杂食性桡足类,它对食物的选择依赖其生活海域中食物的可获得性。 相似文献
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Copepods are among the most abundant and successful metazoans in the marine ecosystem. However, genomic resources related to fundamental cellular processes are still limited in this particular group of crustaceans. Ribosomal proteins are the building blocks of ribosomes, the primary site for protein synthesis. In this study, we characterized and analyzed the c DNAs of cytoplasmic ribosomal proteins(c RPs) of two calanoid copepods, P seudodiaptomus poplesia and A cartia pacifi ca. We obtained 79 c RP c DNAs from P. poplesia and 67 from A. pacifi ca by c DNA library construction/sequencing and rapid amplifi cation of c DNA ends. Analysis of the nucleic acid composition showed that the copepod c RP-encoding genes had higher GC content in the protein-coding regions(CDSs) than in the untranslated regions(UTRs), and single nucleotide repeats(3 repeats) were common, with "A" repeats being the most frequent, especially in the CDSs. The 3′-UTRs of the c RP genes were signifi cantly longer than the 5′-UTRs. Codon usage analysis showed that the third positions of the codons were dominated by C or G. The deduced amino acid sequences of the c RPs contained high proportions of positively charged residues and had high p I values. This is the fi rst report of a complete set of c RP-encoding genes from copepods. Our results shed light on the characteristics of c RPs in copepods, and provide fundamental data for further studies of protein synthesis in copepods. The copepod c RP information revealed in this study indicates that additional comparisons and analysis should be performed on different taxonomic categories such as orders and families. 相似文献
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