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...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.展开更多
Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogeneti...Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.展开更多
目的研究黄芩提取物对临床常见3种耐药菌的体外抑制效果及对16S r RNA甲基化酶基因表达的影响。方法采用纸片扩散法分别测量环丙沙星、黄芩提取物、黄芩提取物+环丙沙星、万古霉素和氨曲南对耐药金黄色葡萄球菌、耐药铜绿假单胞菌和耐...目的研究黄芩提取物对临床常见3种耐药菌的体外抑制效果及对16S r RNA甲基化酶基因表达的影响。方法采用纸片扩散法分别测量环丙沙星、黄芩提取物、黄芩提取物+环丙沙星、万古霉素和氨曲南对耐药金黄色葡萄球菌、耐药铜绿假单胞菌和耐药肺炎克雷伯杆菌的抑菌圈大小,同时采用荧光定量聚合酶链反应方法及琼脂糖凝胶电泳法测定不同药物对细菌16S rRNA甲基化酶mRNA的转录水平。结果黄芩提取物对耐药金黄色葡萄球菌具有良好的抑制作用;黄芩提取物+环丙沙星对耐药铜绿假单胞菌和耐药肺炎克雷伯菌的增殖具有良好抑制作用;黄芩提取物可以抑制耐药铜绿假单胞菌及耐药肺炎克雷伯菌16S rRNA甲基化酶基因的转录。结论黄芩提取物可以降低16S r RNA甲基化酶mRNA转录,提高耐药菌对抗菌药物的敏感性。展开更多
基金This study was supported financially by the National Natural Science Foundation of China （No. 40176028）.
文摘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.
基金supported by the National Natural Science Foundation of China (NSFC, 31000191, 31330073)the Postdoctoral Science Foundation of China (2011 M500537)+2 种基金the Natural Science Foundation of Hebei Province (NSFHB, 2012205018)the Natural Science Foundation of the Department of Education, Hebei Province (YQ2014024) to D. LiNSFHB (2013205018) to Y. Wu
文摘Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.
文摘目的研究黄芩提取物对临床常见3种耐药菌的体外抑制效果及对16S r RNA甲基化酶基因表达的影响。方法采用纸片扩散法分别测量环丙沙星、黄芩提取物、黄芩提取物+环丙沙星、万古霉素和氨曲南对耐药金黄色葡萄球菌、耐药铜绿假单胞菌和耐药肺炎克雷伯杆菌的抑菌圈大小,同时采用荧光定量聚合酶链反应方法及琼脂糖凝胶电泳法测定不同药物对细菌16S rRNA甲基化酶mRNA的转录水平。结果黄芩提取物对耐药金黄色葡萄球菌具有良好的抑制作用;黄芩提取物+环丙沙星对耐药铜绿假单胞菌和耐药肺炎克雷伯菌的增殖具有良好抑制作用;黄芩提取物可以抑制耐药铜绿假单胞菌及耐药肺炎克雷伯菌16S rRNA甲基化酶基因的转录。结论黄芩提取物可以降低16S r RNA甲基化酶mRNA转录,提高耐药菌对抗菌药物的敏感性。
