Comparison and evaluation of the methods for measuring hemolytic activity of <i>Stomolophus meleagris</i> jellyfish tentacle extract

Hemolytic activity assessment is a widely used method to evaluate the toxicity of marine organisms, including jellyfish. However, there are some challenges associated with testing hemolytic activity. In this study, four methods were employed to compare the hemolytic activity of jellyfish tentacle extract (TE). Firstly, a microplate reader was used to compare the mouse hemoglobin solution at three different wavelengths (415 nm, 541 nm, and 576 nm), and the most sensitive wavelength was selected for further experiments. Secondly, photomicrograph counting was used to determine the number of complete red blood cells in the field of view. Thirdly, a microplate reader was used to test hemolytic activity in a 96-well plate at 415 nm. Fourthly, a Bicinchoninic Acid (BCA) kit was used to test the concentration of hemoglobin in the solution. Finally, a UV-Vis Spectrophotometer was used to test hemolytic activity at 415 nm. Among the three wavelengths tested, the absorption value was most sensitive at 415 nm. The photomicrograph counting method was able to reflect changes in the shape of Red Blood Cells (RBCs). The microplate reader method may exhibit deviations when the solution concentration is high, while external factors could influence the BCA kit when the toxin concentration in the experimental group is low. The spectrophotometer method was found to be relatively accurate and sensitive to changes. When optimizing the method, it is important to consider the applicability of the Beer-Lambert law and the concentration of solutions.