Motility and cell division patterns among several strains of Symbiodinium

抄録

The dinoflagellate genus Symbiodinium consists of well-known coral symbionts. The genus is divided into nine phylogenetically distinct groups (clades A-I), with each consisting of numerous small groups (types or sub-clades). Some Symbiodinium can be isolated from host animals and maintained as culture strains under laboratory conditions, but there is currently very little biological information on cultured Symbiodinium. In the present study, we observed motility and cell division patterns in eight Symbiodinium culture strains for clades A-F. Al-though cell division patterns were congruent among all of the culture strains, their motility patterns differed. Peak cell division was observed at dawn in all of the cultures. The ratio of motile phase cells declined at night, but in clade A type A2 relative and clade E Symbiodinium culture strains, which were isolated from the environment, >10% of the cells actively swam at night. While we only investigated eight cultures, we observed similarities and differences in their characteristics. Although several Symbiodinium are difficult to cultivate, future studies on cultured cells would give better insights into the biology of Symbiodinium spp.