Erythrocytes from green turtle hatchlings contain a single embryonic component, unlike those from other cleidoic eggs, in which adult hemoglobin (Hb) constitutes a significant fraction of total Hb at hatching. The functional properties of the isolated and purified green turtle hatchling Hb that distinguish it from adult Hb are a high affinity for oxygen and marked sensitivity to organic phosphate modulators. Hatchling erythrocytes also contain higher concentrations of ATP and 2,3-diphosphoglyceric acid, but their oxygen affinity is indistinguishable from that of adult erythrocytes. Hatchling erythrocyte mean cell volume is approximately half of the adult value, but hematocrit, blood hemoglobin concentration and blood viscosity of hatchlings and adults are similar. Oxygen-carrying capacity in green turtles, unlike that of other diving vertebrates, corresponds with a theoretically derived optimum. The possibility of allosteric control of Hb oxygen-binding in hatchlings may relate not to the challenge of exercise during the dispersal phase but to conditions in the late embryo in the nest.
In the field: an interview with Martha Muñoz
Martha Muñoz is an Assistant Professor at Yale University, investigating the evolutionary biology of anole lizards and lungless salamanders. In our new Conversation, she talks about her fieldwork in Indonesia, Costa Rica, the Dominican Republic and the Appalachian Mountains, including a death-defying dash to the top of a mountain through an approaching hurricane.
Call for new preLighters
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preLights is the preprint highlighting community supported by The Company of Biologists. At the heart of preLights are our preLighters: early-career researchers who select and write about interesting new preprints for the research community. We are currently looking for new preLighters to join our team. Find out more and apply here.
Graham Scott in conversation with Big Biology
Graham Scott talks to Big Biology about the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade.
Trap-jaw ants coordinate tendon and exoskeleton for perfect mandible arc
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Trap-jaw ants run the risk of tearing themselves apart when they fire off their mandibles, but Greg Sutton & co have discovered that the ants simultaneously push and pull the mandibles using energy stored in a head tendon and their exoskeleton to drive the jaws in a perfect arc.
Hearing without a tympanic ear
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In their Review, Grace Capshaw, Jakob Christensen-Dalsgaard and Catherine Carr explore the mechanisms of hearing in extant atympanate vertebrates and the implications for the early evolution of tympanate hearing.
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