Objective 1. Identify and characterize transporters
Identify and characterize the transporters that move ions, particularly Ca2+, HCO3-, or H+ , into or out of the calicoblastic space in the coral Porites astreoides.
Based on our knowledge of ion movement and pH regulation in neurons, we can predict that corals use either a plasmalemma type Na+/Ca2+ exchanger or a bicarbonate exchanger to move calcium and bicarbonate across the apical surface of the calicobalstic epithelial. There are compelling however indirect reasons to suppose each may be the principal player. We propose to clone candidate exchangers, map their distribution, and characterize their physiology in heterologous systems. Further, we propose to use recently settled coral microcolonies as a model for use in microscopy and physiology. Live cell imaging techniques will allow the visualization of Ca2+, voltage and pH dynamics across the calicoblastic epithelia. As a test species we will use Porites astreoides, one of the most abundant species of reef-building coral in the Caribbean. Our approach will provide an opportunity to integrate molecular physiology with imaging to better understand the molecular and cellular events taking place during normal and stressful conditions.
For an overview of the transcriptomics approach we use to understand calcification in corals, check out the eposter HERE.
Fluorescence imaging of corals: