Seven Dunaliella Kinship Identification And Growth Characteristics Compared

Seven strains of Dunaliella sp. preserved in Microalgae Culture Collection Center, were selected as the subject of study. To study and explore these microalgae resources, the effects of salinity, temperature and light intensity on 7 strains of Dunaliella sp. were studied and morphological and molecular classification were also used in the investigation of taxonomic position and genetic relationship. The anti-salt metabolism was preliminarily analyzed. The results showed:1. Seven strains had similar adaptability to the temperature and light intensity; the optimal growth condition was under 25℃,6000lx. However, there were significant differences in their salinity tolerance. The optimal salinity ranged from 50 to 150, and A57 were the best one. A85 got the best multiplication capacity under the optimal culture condition.2. The ribosome 5.8S rDNA and ITS sequences of these Dunaliella sp. were sequenced, and compared with the 7 Dunaliella sequences from Genbank. UPMGA phylogenetic tree revealed that all the seven Dunaliella strains clustered in the same clad with Dunaliella viridis. Considering the appraisal results of cytomorphology and physiology, the studied Dunaliella strains might belong to D. viridis. Within the 7 studied strains, A85 and A57 and A83 were clustered to a clad, while A121 and A124 were clustered to another clad, which was further supported by RAPD analysis using 12 random primers.3. intracellular glycerol content of A57 grown in hypersaline medium indicated that the adjustment of glycerol content finished in 6 hours after hyperosmotic shock. After three weeks, some functional proteins were induced significantly, protein 75KD,70KD,15KD, whose amounts enhanced nearly two times; protein26KD,36KD,40KD,almost doubled, while expression of protein 54KD, 108KD were strongly restrained.4. Applied FDA-PI double staining method with FCM to detect the cell viability and morphological changes of A57 after hyperosmotic shock, the results indicated that the cellular contents decreased quickly at the initial stage, while cell volume increased. The nonviable cell percent rised evidently in 6 hour, and remained stable until 24 hours after the shock.