The Comparison between Toxic Pseudo-nitzschia multiseries (Hasle) Hasle and Non-toxic P. pungens (Grunow) Hasle Isolated from Jinhae Bay, Korea

Algae > Volume 16(3); 2001 > Article

Algae 2001;16(3): 275-285.

Eun Seob Cho, Yuichi Kotaki, Jong Gyu Park

Harmful Algal Research Division, Fisheries Research and Development Institute, School of Fisheries Sciences, Kitasato University, The Institute of Environment Research, Inje University

ABSTRACT

We studied the ecological characteristics of Pseudo-nitzschia multiseries and P. pungens, comparing the morphology, toxin production, growth and ITS sequences. On the basis of transmission electron microscopy (TEM), it was found that P. pungens had 9-12 fibulae in 10 ㎛, 2 rows of poroids, 3-4 poroids in 1 ㎛ and 9-11 striae in 10 ㎛, while in P. multiseries 13-14 fibulae in 10 ㎛, 3-4 rows of poroids, 4-6 poroids in 1 ㎛ and 13-14 striae in 10 ㎛. Domoic acid (DA) production by P. multiseries was determined by HPLC with UV or fluorometric detection, and resulted in 221.8 ng?mL-1, 196.4 ng?mL-1 and 25.4 ng?mL-1 in the whole culture, cell-free medium and cell fraction, respectively, for 20 days at 20℃ under light intensity of 100 μmol?m-2?s-1 with 16:8 LD cycle, while values for P. pungens were negative. Both P. multiseries and P. pungens showed a higher growth rate at higher temperature with the highest growth rate at 20℃. Pseudo-nitzschia multiseries had a wide range of salinity (20-40 psu) for optimal growth, but at 40 psu and 50 psu, the growth rate of P. pungens was lower than that of P. multiseries. In particular, 10 psu did not allow any growth of P. mutiseries. For nitrate, ammonium and urea-grown culture, nutrient concentration contributed to a variation of growth, in which the best growth was obtained at 100 μM. However, P. multiseries grew well even in a medium without urea, while the growth rate of P. pungens was significantly different (p

Key words: gene sequence, growth, morphology, Pseudo-nitzschia multiseries, P. pungens, toxin