Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas

Gerald Soslau, Bryan Wallace, Catherine Vicente, Seth J. Goldenberg, Todd Tupis, James Spotila, Robert George, Frank Paladino, Brent Whitaker, Gary Violetta, Rotney Piedra

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the Jurassic period. Sea turtles are often exposed to rapidly altered environmental conditions during diving periods. This may reduce their blood pH during prolonged hypoxic dives. This report demonstrates that five species of turtles possess only one branch of the mammalian coagulation pathway, the extrinsic pathway. Mixing studies of turtle plasmas with human factor-deficient plasmas indicate that the intrinsic pathway factors VIII and IX are present in turtle plasma. These two factors may play a significant role in supporting the extrinsic pathway by feedback loops. The intrinsic factors, XI and XII are not detected which would account for the inability of reagents to induce coagulation via the intrinsic pathway in vitro. The analysis of two turtle factors, factor II (prothrombin) and factor X, demonstrates that they are antigenically/ functionally similar to the corresponding human factors. The turtle coagulation pathway responds differentially to both pH and temperature relative to each turtle species and relative to human samples. The coagulation time (prothrombin time) increases as the temperature decreases between 37 and 15°C. The increased time follows a linear relationship, with similar slopes for loggerhead, Kemps ridley and hawksbill turtles as well as for human samples. Leatherback turtle samples show a dramatic nonlinear increased time below 23°C, and green turtle sample responses were similar but less dramatic. All samples also showed increased prothrombin times as the pH decreased from 7.8 to 6.4, except for three turtle species. The prothrombin times decreased, to varying extents, in a linear fashion relative to reduced pH with the rate of change greatest in leatherbacks>green≫loggerhead turtles. All studies were conducted with reagents developed for human samples which would impact on the quantitative results with the turtle samples, but are not likely to alter the qualitative results. These comparative studies of the coagulation pathway in sea turtles and humans could enhance our knowledge of structure/function relationships and evolution of coagulation factors.

Original languageEnglish (US)
Pages (from-to)399-406
Number of pages8
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Issue number4
StatePublished - Aug 2004
Externally publishedYes


  • Coagulation cascade
  • Hemostasis
  • Prothrombin

ASJC Scopus subject areas

  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Biochemistry
  • Physiology


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