Previous studies found intraspecific diversity in Scrippsiella trochoidea A. R. Loeblich Ill, a widely distributed calcareous cyst-producing dinoflagellate. In this study, three strains （ST-I, ST-D6 and ST-K） of S. ...Previous studies found intraspecific diversity in Scrippsiella trochoidea A. R. Loeblich Ill, a widely distributed calcareous cyst-producing dinoflagellate. In this study, three strains （ST-I, ST-D6 and ST-K） of S. trochoidea isolated from the East Asian waters were studied, together with other geographical strains, to resolve their phylogenetic relationships. For the three East Asian isolates, two highly diverse regions of nuclear-encoded ribosomal DNA （rDNA）, the 5.8S rDNA and its flanking internal transcribed spacers 1 and 2, and the 5＇ portion of the large-subunit rDNA （encompassing the ＂DI＂ and ＂D2＂ domains） were sequenced. Homologous sequences from other geographical isolates were selected from the GenBank database and the phylogenetic relationships were inferred from the molecular data of these strains. Strains of S. trochoidea were found to cluster into three major clades （STR1, STR2 and STR3）, as reported in previous studies. Two of the three strains ST-1 and ST-K, were grouped in clade STR2, the other strain, ST-D6, belonged to clade STR3. The intraspecific diversity ofS. trochoidea in East Asian waters makes it necessary to carry out phylogenetic investigations in combination with data of biogeography, population dynamics, and life cycle on the ecophysiology of a region.展开更多
The authors consider relational databases organized over an ordered domain with some additional relations - a typical example is the ordered domain of rational numbers together with the operation of addition. In the f...The authors consider relational databases organized over an ordered domain with some additional relations - a typical example is the ordered domain of rational numbers together with the operation of addition. In the focus of our study are the FO （first-order） queries that are invariant under order-preserving permutations-such queries are called order-generic. It was discovered that for some domains order-generic FO queries fail to express more than pure order queries. The collapse result theorem was proved for locally genetic queries over a linearly ordered domain with the Pseudo finite Homogeneity Property （or / and the Isolation Property） by Belegradek et al.. Here the authors consider a circularly ordered domain and prove the collapse result theorem over a quasi circularly minimal domain.展开更多
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences （No. KZCX2-YW-208） and National Natural Science Foundation of China （No. 40676072）
文摘Previous studies found intraspecific diversity in Scrippsiella trochoidea A. R. Loeblich Ill, a widely distributed calcareous cyst-producing dinoflagellate. In this study, three strains （ST-I, ST-D6 and ST-K） of S. trochoidea isolated from the East Asian waters were studied, together with other geographical strains, to resolve their phylogenetic relationships. For the three East Asian isolates, two highly diverse regions of nuclear-encoded ribosomal DNA （rDNA）, the 5.8S rDNA and its flanking internal transcribed spacers 1 and 2, and the 5＇ portion of the large-subunit rDNA （encompassing the ＂DI＂ and ＂D2＂ domains） were sequenced. Homologous sequences from other geographical isolates were selected from the GenBank database and the phylogenetic relationships were inferred from the molecular data of these strains. Strains of S. trochoidea were found to cluster into three major clades （STR1, STR2 and STR3）, as reported in previous studies. Two of the three strains ST-1 and ST-K, were grouped in clade STR2, the other strain, ST-D6, belonged to clade STR3. The intraspecific diversity ofS. trochoidea in East Asian waters makes it necessary to carry out phylogenetic investigations in combination with data of biogeography, population dynamics, and life cycle on the ecophysiology of a region.
文摘The authors consider relational databases organized over an ordered domain with some additional relations - a typical example is the ordered domain of rational numbers together with the operation of addition. In the focus of our study are the FO （first-order） queries that are invariant under order-preserving permutations-such queries are called order-generic. It was discovered that for some domains order-generic FO queries fail to express more than pure order queries. The collapse result theorem was proved for locally genetic queries over a linearly ordered domain with the Pseudo finite Homogeneity Property （or / and the Isolation Property） by Belegradek et al.. Here the authors consider a circularly ordered domain and prove the collapse result theorem over a quasi circularly minimal domain.
