Nematode Diversity of Qingdao Coast Inferred from the 18S Ribosomal RNA Gene Sequence Analysis  

作　　者：SHEN Xiquan YANG Guanpin LIU Yongjian 

机构地区：[1]College of Marine Life Sciences, Ocean University of China, Qingdao 266003, P.R. China [2]Faculty of Life Science and Biotechnology, Ningbo University, Ningbo 315211, P.R. China

出　　处：《Journal of Ocean University of China》2007年第2期132-136,共5页中国海洋大学学报（英文版）

基　　金：This study was supported financially by the National Natural Science Foundation of China （No. 40176028）.

摘　　要：The 18S ribosomal DNA gene （18S rDNA） sequences （approxtmately 1300 bp in length） were amplified from the DNA extracted from the free-living marine nematodes collected from the inter-tidal sediment of Qingdao coast in bulk with nematode specific primers. The PCR products were cloned, re-amplified, digested with Rsa I and Hin61 restriction endonucleases and separated in agarose gel. Among 17 restriction fragment length types, types 1, 2 and 6 covered 61.2%, 14.4% and 9.3% of the clones analyzed, respectively, while the remaining 14 only covered 21 clones, which accounted for 15.1% of the total. Twenty-four representative clones were sequenced and phylogenetically analyzed by referring to those currently available in RDP and GenBank databases. Although it was hard to assign these sequences to known species or genera due to the lack of the 18S rDNA sequence data of known marine free-living nematodes, the obtained sequences were assigned to the nematodes of Adenophorea. Among them, twelve sequences were close to Pontonema vulgate and Adoncholaimus sp., four to Daptonema procerus and two （identical） to Enoplus brews. Our results showed that free-living marine nematode diversities could be determined by PCR retrieving and analysis of the 18S rDNA sequences and an 18S rDNA sequence could be assigned to a species or a genus only if the 18S rDNA sequences of the free-living marine nematodes were accumulated to some extent.The 18S ribosomal DNA gene (18S rDNA) sequences (approximately 1300 bp in length) were amplified from the DNA extracted from the free-living marine nematodes collected from the inter-tidal sediment of Qingdao coast in bulk with nematode spe- cific primers. The PCR products were cloned, re-amplified, digested with Rsa I and Hin6 I restriction endonucleases and separated in agarose gel. Among 17 restriction fragment length types, types 1, 2 and 6 covered 61.2%, 14.4% and 9.3% of the clones analyzed, respectively, while the remaining 14 only covered 21 clones, which accounted for 15.1% of the total. Twenty-four representative clones were sequenced and phylogenetically analyzed by referring to those currently available in RDP and GenBank databases. Al- though it was hard to assign these sequences to known species or genera due to the lack of the 18S rDNA sequence data of known marine free-living nematodes, the obtained sequences were assigned to the nematodes of Adenophorea. Among them, twelve se- quences were close to Pontonema vulgare and Adoncholaimus sp., four to Daptonema procerus and two (identical) to Enoplus brevis. Our results showed that free-living marine nematode diversities could be determined by PCR retrieving and analysis of the 18S rDNA sequences and an 18S rDNA sequence could be assigned to a species or a genus only if the 18S rDNA sequences of the free-living marine nematodes were accumulated to some extent.

关 键 词：NEMATODE DIVERSITY 18S ribosomal RNA gene RDNA 

分 类 号：Q178.531[生物学—水生生物学] Q959.17[生物学—普通生物学]