The Florida manatee, Trichechus manatus latirostris, has shown hypercoagulation properties compared to other mammals. This hypercoagulation may be the result of environmental evolutionary pressures in response to dietary factors. Hypercoagulation in manatees is known to affect clotting factor activity and thromboelasticity (TEG) leading to exaggerated thromboembolic disease and cold stress syndrome. It is suspected that the seagrasses comprising wild manatee diets Halodule wrightii, Syringodium filiforme, and Thalassia testudinum (all native to Tampa Bay region of Florida) contain anticoagulatory properties. Romaine lettuce, Lactuca sativa var. longifolia, was used as a control to simulate the diet of a manatee in captivity. To understand the coagulative properties of the native Tampa Bay seagrasses comprising manatee diets, we performed sequential extractions of dried sea grass samples. The extractions increased in polarity, starting with hexane, dichloromethane (DCM), ethyl acetate (EtOAc), and methanol. All extracts were isolated and frozen to be used for future assays to determine thrombotic effects of extracted compounds. Activated partial thrombin time (APTT) assays were performed to assess the intrinsic coagulation cascade. Utilizing heparin as a known anticoagulant, organic extract assays were run in comparison. Calcium chloride was used as a coagulation cascade activator. Heparin coagulation times were normalized to indicate effectiveness of anticoagulants identified in seagrass samples. Based on normalized data all species including the romaine control show anticoagulant activity in varying degrees and samples. Future investigation into the anticoagulative activity of Tampa Bay seagrasses will include the replication of this study, and the calculation of EC50 values for each grass species and extract to understand and compare inhibitory effects on the coagulation cascade.

Lisa Bonner

Eckerd College

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