Molecular Mechanisms Regulating Food Choice In Bivalves

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

__________________________________________________________________________________________________ Molecular Mechanisms Regulating Food Choice In Bivalves Emmanuelle Pales Espinosa & Bassem Allam, Stony Brook University Bivalve mollusks, such as oysters, clams and mussels, are among the most important organisms living in coastal and estuarine ecosystems. Bivalves have high commercial value as seafood, and provide important ecosystem services, such as clearing water, stabilizing soft sediments, providing habitat and serving as prey to larger animals. A single bivalve can filter several liters of water each hour, selecting the most nutritious particles to optimize energy gain and rejecting undesirable silt and debris. While this general process has been known for decades, understanding the mechanisms bivalves use to accurately sort particles is key to understanding the role bivalves serve in complex coastal food webs. This project will investigate how bivalves identify and select their food particles. It is hypothesized bivalve feeding structures identify specific molecules on the surface of food particles. These molecular factors will be characterized using several state-of-the-art analytical tools. The project will provide research training to postdoctoral researchers as well as graduate, undergraduate and high school students. The project will also establish a series of outreach events organized in partnership with a public aquarium to introduce the general public to hot topics in marine research, including the importance and sensitivity of marine resources. Overall, the results and educational initiatives will contribute to the promotion of science in general and to improved stewardship of coastal natural resources. This project will identify biochemical cues and underlying regulatory mechanisms that mediate particle sorting in suspension-feeding bivalves. Based on preliminary findings, the central hypothesis is that particle sorting in these animals is controlled by interactions between microalga cell surface carbohydrates and carbohydrate-binding proteins (lectins) present in mucus covering bivalve feeding organs. Using complementary molecular and physiological approaches and techniques, the bases of particle selection at the levels of the cell, organ and species will be probed and the major factors that mediate particle sorting will be elucidated. Several lines of research have been developed to (1) evaluate whether carbohydrate-protein interactions represent a main driver for sorting across suspension-feeding bivalves, (2) identify microalgae carbohydrates driving selection, (3) determine the functional role of carbohydrate-binding proteins in particle sorting, and (4) assess how these proteins are regulated. Findings from this project are expected to transform the field by (1) validating a novel concept establishing the role of carbohydrate-protein interactions to provide particle sorting on-the-fly, by (2) generating data needed to develop a mechanistic model for particle sorting in bivalves, and by (3) supporting a new dimension for the role of some evolutionarily-conserved lectins in the Metazoa. Altogether, this new information is highly needed to unravel interspecific interactions that regulate pelagic-benthic coupling and energy flow in coastal systems.