Abstract
The growth of harmful microalga, Prymnesium parvum, causes red tides in embayments all over the world, and has caused severe damage to fisheries. The 4 chelators, such as bipyridine, ferrozine, bathophenanthroline disulphonate, or desfferrioxamine B, which bind iron, were evaluated for preventing P. parvum from growing under iron limitation. Only bipyridine and desfferrioxamine B inhibited the growth of microalga. Presumably, the two chelators will prevent P. parvum from uptaking iron and lead to iron deficiency. Furthermore, for the molecular mechanism of microalgal cells adapting to iron deficiency, the functional genes induced the transcription by means of iron deficiency were cloned using differential display analysis. The total 68 clones obtained were classified into 12 genetic types, of which 6 types were similar to the known functional genes and 6 types that indicated unknown sequences. The reverse northern analysis demonstrated that, among the 12 types, the transcriptions of 9 types were induced in the iron deficiency algal cells. The 3 types of the known functional genes, such as eucaryotic release factor, enolase, and heat shock protein, occupied 24 of the total 68 clones, suggesting that the algal cells under the stress of iron deficiency induce to transcript these functional genes to adapt to the environmental stress. In conclusion, the iron chelators reducing the algal growth may be a useful tool for regulating the harmful microalgal biomass, and the iron deficiency may provide the physiological stress for the microalgal cells.
