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...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 se- quences, and a putatively encoding ?5 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/Baci- llariales/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 ?5 desaturase similarity was 99.4%. However, the lower similarity was disclosured between N. closterium f. minutis- sima and Cylindrotheca closterium, which shared less than 40% identity in the ITS1 and ITS2 se- quences. 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. tri- cornutum.展开更多
研究了4种溢油分散剂对青岛大扁藻(Platymonas helgolandica var.tsingtaoensis)和小新月菱形藻(Nitzschia closterium f.minutissima)细胞密度和叶绿素含量的影响。实验结果表明:DL、GZ、WP和GM 4种溢油分散剂对青岛大扁藻生长的96 h E...研究了4种溢油分散剂对青岛大扁藻(Platymonas helgolandica var.tsingtaoensis)和小新月菱形藻(Nitzschia closterium f.minutissima)细胞密度和叶绿素含量的影响。实验结果表明:DL、GZ、WP和GM 4种溢油分散剂对青岛大扁藻生长的96 h EC50值分别是0.0722、0.1852、0.1889和0.7198 g·L^(–1);对小新月菱形藻的96 h EC_(50)值分别是0.0511、0.2592、0.2939和0.5816 g·L^(–1)。对青岛大扁藻的96 h EC50-chl-a为0.0433、0.1325、0.1517和0.5121 g·L^(–1),96 h EC_(50)-chl-b为0.0503、0.1719、0.1212和0.3091 g·L^(–1);对小新月菱形藻的96 h EC_(50)-chl-a为0.0425、0.1365、0.1470和0.4215 g·L^(–1)。随溢油分散剂浓度的增加,2种微藻的细胞密度和叶绿素含量显著下降,呈现显著的剂量—效应关系。根据半数抑制浓度值,4种溢油分散剂的毒性大小为DL>GZ>WP>GM。与细胞密度相比,2种微藻的叶绿素含量对4种溢油分散剂更敏感,更适于作为评判溢油分散剂毒性大小的指标。展开更多
基金the National Basic Research Program of China (Grant No. 2005CCA02400)
文摘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 se- quences, and a putatively encoding ?5 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/Baci- llariales/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 ?5 desaturase similarity was 99.4%. However, the lower similarity was disclosured between N. closterium f. minutis- sima and Cylindrotheca closterium, which shared less than 40% identity in the ITS1 and ITS2 se- quences. 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. tri- cornutum.
文摘研究了4种溢油分散剂对青岛大扁藻(Platymonas helgolandica var.tsingtaoensis)和小新月菱形藻(Nitzschia closterium f.minutissima)细胞密度和叶绿素含量的影响。实验结果表明:DL、GZ、WP和GM 4种溢油分散剂对青岛大扁藻生长的96 h EC50值分别是0.0722、0.1852、0.1889和0.7198 g·L^(–1);对小新月菱形藻的96 h EC_(50)值分别是0.0511、0.2592、0.2939和0.5816 g·L^(–1)。对青岛大扁藻的96 h EC50-chl-a为0.0433、0.1325、0.1517和0.5121 g·L^(–1),96 h EC_(50)-chl-b为0.0503、0.1719、0.1212和0.3091 g·L^(–1);对小新月菱形藻的96 h EC_(50)-chl-a为0.0425、0.1365、0.1470和0.4215 g·L^(–1)。随溢油分散剂浓度的增加,2种微藻的细胞密度和叶绿素含量显著下降,呈现显著的剂量—效应关系。根据半数抑制浓度值,4种溢油分散剂的毒性大小为DL>GZ>WP>GM。与细胞密度相比,2种微藻的叶绿素含量对4种溢油分散剂更敏感,更适于作为评判溢油分散剂毒性大小的指标。
