Purple Sea Urchin Metamorphosis Nothing to Sneeze At, Study Shows
During hay fever season, it is easy to forget that symptom-inducing histamine also helps regulate sleep and control memory and stomach acidity. A study co-authored by University of Guelph integrative biology professor Andreas Heyland shows that, for the purple sea urchin (Strongylocentrotus purpuratus), histamine controls its development from a larva into a spiny adult.
Heyland’s research team found that histamine is an important regulator for reaching metamorphic competence the stage directly preceding the transition of sea urchins into their adult form.
“Histamine-containing cells in metamorphically competent purple sea urchin larvae.” From Sutherby et al. in press, BMC Developmental Biology
Echinoids, like sea urchins and sand dollars, have a diversity of developmental strategies. In one, a free-swimming (pelagic) larva can spend an extended period of searching for an appropriate environment to “settle” and then grow into its adult (benthic) form and live on the sea floor. During this metamorphosis, most larval structures, such as its arms, are absorbed and juvenile structures emerge, such as tube feet for movement, feeding and sensing the environment.
The researchers discovered that histamine plays a key role in the purple sea urchin’s maturation process.
“Histamine is an important signaling molecule controlling purple sea urchin competence and metamorphosis,” said Heyland. “When we examined the effects of histamine, we found that it inhibited programmed cell death (PCD), which is essential to the transition process from larva to adult. In our experiments we were able to induce PCD and arm reabsorption with several antihistamines.”
One antihistamine, AMH, that blocks production of the sea urchin’s own histamine, also resulted in a higher settlement rates.
Heyland said the study was also special because three of the authors are undergraduate students in his lab. “It is nice to accomplish something so complete and significant based on undergraduate projects.”
The study, “Histamine is a modulator of metamorphic competence in Strongylocentrotus purpuratus (Echinodermata: Echinoidea)”, has been published in the open access, peer-reviewed journal, BMC Developmental Biology.