About the Cover
Cover
The image shown on the cover is a five-day-old larva of the purple sea urchin Strongylocentrotus purpuratus. It was produced using confocal microscopy of a whole larva incubated with antibodies designed to reveal the presence of a specific amino acid transporter protein (gene Sp-AT1). The red color represents larval tissues labeled by the antibody (pseudo-colored), and the green is DNA showing the distribution of cells.
For over a century, biologists have speculated that the enormous pool of dissolved organic carbon in the world's oceans might serve as an important nutritional resource for marine invertebrates. During the past 50 years or so (the “modern era” of this field of comparative physiology), experimental approaches using chromatography and radioisotopes showed that the ability to transport dissolved organic nutrients from seawater was widespread among marine invertebrate phyla. For larval stages, the genes involved in these processes have remained unknown.
In this issue (pages 6–24), Meyer and Manahan demonstrate the presence in the sea urchin of specific genes involved in the process by which the larva takes up nutrients dissolved at low concentrations in seawater. They describe the cloning and functional characterization of three amino acid transporter genes in developmental stages of the sea urchin. These genes are present over the external surface of the larva (ectoderm), in direct contact with seawater. This advance in the field of nutrient transport by marine invertebrates will enable future research into long-standing questions, such as the mechanisms of activation of transport systems during early development and the role of these transporters in metabolism. These findings connect a physiological process that has been studied for a century with specific genes in the recently sequenced sea urchin genome.
Photo credit: Confocal image by Pauline Yu, University of Southern California. Cover design: Beth Liles, Marine Biological Laboratory.
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Copyright © 2009 by the Marine Biological Laboratory.
