Digestive Enzymes of the Giant Keyhole Limpet

Abstract

Stellar Biotechnologies Inc in Ventura is culturing the giant keyhole limpet, Megathura crenulata and extracting its respiratory pigment (KLH, keyhole limpet hemocyanin) from the blood. This respiratory pigment has recently been tested in immunological cancer therapies with some success, therefore in the near future the culture of these animal may become more significant. Although the newly developed culture system is successful, a better understanding of the nutritional preferences and digestive capabilities of the giant keyhole limpet could lead to improved techniques. While morphological studies do yield important information on the specific regions of the gut and the prescence or absence of parasites in these areas, knowledge of the enzymatic activity is also essential. It can be used to adjust the ratio of protein, carbohydrate and lipid fed to the animals in culture. To acquire this data, we performed two different types of enzymatic tests. The API ZYM kit (Biomerieux) yielded semi-quantitative data on 20 common digestive enzymes using a comparative color scale. The second method provides quantitative evaluation of specific enzymes using a fluorometric plate reader. To date I have recorded protease and α-amylase activity in 6 specific regions of the gut of 4 separate animals. Future data collected from ten distinct animals on levels of other enzymessuch as lipase, lysozyme and cellulose combined with my current results will be very useful in understanding the digestive process in the Giant Keyhole limpet.