한국 남해 연안에서 분리한 Alexandrium catenella와 A. pacificum의 환경변화에 따른 마비성패독 생산과 진주담치의 독화 양상

Abstract

Experiments on the growth and toxicity of A. catenella and A. pacificum a representative causative species of paralytic shellfish poisoning in Korea, were conducted. Toxicity changes due to physical factors such as water temperature, salinity, light intensity and quality were carried out in the laboratory. Growth rate and toxicity change were examined under the following combination of temperature: 5, 10, 15, 20, 25 and 30℃, and salinity: 15, 20, 25, 30 and 35 psu. No growth was observed with a temperature of 10℃ at A. catenella and 5℃ and 30℃ at A. pacificum. The optimal growth range of A. catenella and A. pacificum were 20-25℃ in temperature. There was correlation with water temperature change except that A. catenella showed high toxicity at low water temperature (10-15℃) and A. pacificum showed high toxicity at 25℃. A. catenella and A. pacificum grow well in all salinity range and are euryhaline organism. There was no significant difference in the toxicity change according to the salinity change. In light intensity experiment, A. catenella decreased the toxicity as the light intensity increased and A. pacificum increased the toxin content as the light intensity increased. Light quality experiment was performed under fluorescent lamps, blue, green and red LEDs, Both A. catenella and A. pacificum showed the highest toxicity and toxicity in red wavelengths. Arginine, a precursor of paralytic toxic poison, is an amino acid constituting protein, and indirectly inferred the concentration of arginine, a precursor of PSP, by measuring protein. As a result of the protein analysis according to the light quality change, the highest protein content was found in the red wavelength. Therefore, it can be inferred that the high arginine concentration in the red wavelength contributed to the production of paralytic shellfish toxins. In addition, these proteins are converted to the final product ammonium when the primary producer absorbs DIN (nitrate; NO3-N, nitrite; NO2-N, ammonium; NH4-N) in the seawater, and is used for protein synthesis. Therefore, if the nitrogen content is high, there is a possibility of promoting paralytic shellfish poisoning production. In this study, the toxicity changes as ammonia concentrations at different wavelengths showed high toxicity at high nitrogen concentrations. Therefore, it is suggested that if artificial nitrogen is introduced into the sea area where paraltyci shellfish poisoning occurs, such as dredging business or nitrogen fertilizer, it will promote PSP. Overall, A. catenella is considered to be a species that contributes to PSP generation because it is most toxic in the surface water temperature range in March when paralytic shellfish poisoning occurs in spring. In salinity, both species are euryhaline, and there is no significant difference in the toxicity change due to salinity change. Therefore, the effect of salinity change on the toxicity in the general Korean marine environment is considered to be insignificant. In addition, if the light intensity decreases over a long period of time, such as on a cloudy day, it may suggest the possibility of promoting paralytic shellfish poisoning. Although the light quality showed the highest toxicity in the red wavelength, in the general marine environment, red wavelengths are the most absorbing wavelengths in the ocean. Vertically shifted dinoflagellate may have minimal effect on the production of paralytic shellfish poisoning. Experiments on the change of toxicity of mussels grown in near Gwanpo Port in Geoje Island began to feed as soon as the feed organisms were administered. Toxicity began to increase after 3 days and peaked after 7 days. In addition, there is a positive correlation between the presence of A. catenella and the toxicity of mussels and the highest toxicity was found depending on the surrounding nitrogen concentration. In addition, with the increase in the amount of A. catenella, the toxicity of mussels increased immediately in 2018, but increased after a week in 2019. In conclusion, A. catenella, which is highly toxic at low water temperature, reached its highest level in March and May, but from May, the water temperature rose to 15℃ or higher, indicating that its low toxin content did not affect paralytic toxic production and nitrogen concentrations in the surrounding ocean not only amplify paralytic shellfish poisoning production but also suggest the possibility of premature expression in bile after feeding on food organisms.