%0 Journal Article
%T Hierarchical recognition on the taxonomy of Nitzschia closterium f. minutissima
%A Juan Shi
%A KeHou Pan
%A XiaoQing Wang
%A Fang Chen
%A Mi Zhou
%A BaoHua Zhu
%A RenWei Qing
%J Chinese Science Bulletin
%@ 1861-9541
%D 2008
%I 
%R 10.1007/s11434-008-0080-4
%X Nitzschia closterium f. minutissima, a marine eukaryotic unicellular diatom, originally classified as Bacillariophyta/Bacillariophyceae/Bacillariales/Bacillariaceae/Nitzschia, is one of the most important feed sources in mariculture. In this study, its morphological features were examined under DIC Microscopy (differential interference contrast microscope); its pigments and fatty acids composition were analyzed by using High Performance Liquid Chromatography (HPLC) and gas chromatography (GC); the complete Actin cDNA, part 18S rDNA, complete ITS1 and ITS2 sequences, part 28S rDNA sequences, and a putatively encoding жд5 fatty acid desaturase gene were cloned respectively and further functioned in transgenic yeast. The sequence alignments were separately conducted using the related sequences from Nitzschia closterium f. minutissima, Cylindrotheca closterium (Bacillariophyta/Bacillariales/Bacillariaceae/Cylindrotheca) and Phaeodactylum tricornutum (Naviculales) with ClustalX 1.83. No distinct difference was discovered between N. closterium f. minutissima and P. tricornutum in both biochemical and molecular level. Their identity was more than 99.6% among 18S rDNA, 5.8S rDNA and actin-gene sequences, and is up to 98.6% even among ITS1 and ITS2 sequences. Their жд5 desaturase similarity was 99.4%. However, the lower similarity was disclosured between N. closterium f. minutissima and Cylindrotheca closterium, which shared less than 40% identity in the ITS1 and ITS2 sequences. So, N. closterium f. minutissima should not be placed in Bacillariales, Bacillariaceae, Nitzschia, but in Naviculales, Phaeodactylaceae, Phaeodactylum, and it was actually a strain of P. tricornutum.
%K Nitzschia closterium f. minutissima
%K Phaeodactylum tricornutum
%K Cylindrotheca closterium
%K taxonomy
%U http://link.springer.com/article/10.1007/s11434-008-0080-4