ANALYSIS OF EXPRESSED SEQUENCE TAGS FROM THE MARINE MICROALGA NANNOCHLOROPSIS OCULATA (EUSTIGMATOPHYCEAE)(1)

Nannochloropsis oculata (Droop) D. J. Hibberd (Eustigmatophyceae), a marine eukaryotic unicellular alga, is widely used in mariculture as live feed. It is considered to be of high nutritional value owing to its high content of proteins; polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA, C20:5n3); and diverse pigments. Previous studies of this microalga focused on its taxonomy, culture, and biochemistry, but little is known at the molecular level. Establishing a molecular base is vital to understand the biological processes of this alga. Therefore, we constructed a cDNA library using algal cells grown at exponential growth phase and carried out expressed sequence tag (EST) analysis. A total of 1,960 nonredundant sequences (NRSs) were generated for N. oculata clone CS-179. Only 32.5% of NRSs showed significant similarity (E < 1e-04) to proteins registered in the GenBank nonredundant protein database. The KOG (clusters of euKaryotic Orthologous Groups) profile database returned significant hits for 490 NRSs. Analysis revealed that a large proportion of NRSs could be unique to this microalga.