Megathura Crenulata and its Physiological Response to Blood Loss
Mentor:Gary Martin, Professor of Biology, Occidental College
Megathura crenulata, the giant keyhole limpet, is a vetigastropod whose body weight is composed of fifty percent blood, and Stellar Biotechnologies is a company involved in the collection and purification of this invertebrate's blood. Specifically, they are interested in keyhole limpet hemocyanin (KLH), a molecule used in the possible prevention and treatment of human cancers and allergies. KLH is a respiratory pigment analogous to human hemoglobin, however, it is not contained within blood cells but floats freely in the plasma. Stellar has demonstrated that bleeding the limpet by 20% of its body weight is a nonfatal bleed. We are interested in the effects of removing this volume of blood on the physiology of the limpet. Specifically, when does the blood volume return to pre-bleed levels, must the animal resort to anaerobic metabolism while KLH levels are low, when do KLH levels return to normal, and if limpets are maintained under hypoxic conditions do they increase their plasma concentration of KLH? Additionally, the blood contains cells called hemocytes which are the main effector cells of the limpet immune system. We have shown that substantial bleedings stimulate the production of circulating blood cells by incorporating 5-ethynyl-2’-deoxyuridine (EdU), a fluorescent tag into the DNA of dividing cells at various times following bleeds. Preliminary results indicate that there is a peak of cell division 24 to 48 hours post bleed followed by a significant decrease in cell division after a week. This summer we have developed the procedures to address these topics and believe we can successfully address our research questions in future studies.