[Studies on performance standard for hemolytic toxins in harmful bloom algae]

Abstract

Objective: To explore a performance standard for hemolytic toxins in harmful bloom algae.

Methods: Using Chattonella marina as hemolytic substances producing organism, methods and conditions were compared and optimized including cell breakage, distillation temperature, blood origin and storage of algal pellets in extraction and activity determination of hemolytic toxins.

Results: The hemolytic activity of C. marina broken by supersonic method was 288.23 HU/L, higher than that by freezing--thawing method (94.89 HU/L), suggesting that supersonic method could be more optimal to break microalgal cells. When the supersonic treatment times were 5, 10, 20 and 30 min, the hemolytic activities were 80.57, 157.45, 288.23 and 279.17 HU/L, respectively, indicating that 20 min of supersonic treatment was suitable. When the distillation temperature were 40, 60 and 80 degrees C, the hemolytic activities were 288.23, 124.97 and 120.68 HU/L, respectively, meaning that high distillation temperature in extraction of hemolytic substances lowed the hemolytic activities of samples. Bloods from various animals such as human, fish, rat and rabbit exhibited different sensitivity to the hemolytic toxins, of which rabbit erythrocyte was the most sensitive. The hemolytic activities to human, fish, rat and rabbit were 244.98, 288.23, 266.35 and 195.47HU/L, respectively. The storage of algal pellets for 3 days at the temperature of 0 degrees C did not reveal a significant loss in hemolytic activity, while significant losses were observed at the temperature of 20 degrees C or -20 degrees C only after one day.

Conclusion: Supersonic method could be more optimal to break cell in comparison with freeze-thaw method. Optimal conditions for broken algal cells by supersonic method were 200 W for 20 min at the temperature of 4 degrees C. The distillation temperature in extraction of hemolytic substances should be maintained under the temperature of 40 degrees C. The rabbit erythrocyte could be the most optimal blood to detect hemolytic activity due to its high sensitivity. The algal pellets could be kept at the temperature of 0 degrees C for 3 days before determination of activity.