Comparison of proton-specific ATPase activities in plume and root tissues of two co-occurring hydrocarbon seep tubeworm
- PDF / 411,988 Bytes
- 8 Pages / 595 x 791 pts Page_size
- 100 Downloads / 134 Views
ORIGINAL PAPER
Comparison of proton-speciWc ATPase activities in plume and root tissues of two co-occurring hydrocarbon seep tubeworm species Lamellibrachia luymesi and Seepiophila jonesi Sharmishtha Dattagupta · Meredith Redding · Kathryn Luley · Charles Fisher
Received: 21 April 2008 / Accepted: 8 January 2009 / Published online: 31 January 2009 © Springer-Verlag 2009
Abstract Lamellibrachia luymesi and Seepiophila jonesi are co-occurring species of vestimentiferan tubeworms found at hydrocarbon seepage sites on the upper Louisiana slope of the Gulf of Mexico. Like all vestimentiferans, they rely on internal sulWde-oxidizing symbiotic bacteria for nutrition. These symbionts produce hydrogen ions as a byproduct of sulWde oxidation, which the host tubeworm needs to eliminate to prevent acidosis. The hydrothermal vent tubeworm Riftia pachyptila uses a high activity of P- and V-type H+-ATPases located in its plume epithelium to excrete protons. Unlike R. pachyptila, the seep species grow a posterior root, which they can use in addition to their plumes as a nutrient exchange surface. In this study we measured the ATPase activities of plume and root tissues collected from L. luymesi and S. jonesi, and used a combination of inhibitors to determine the relative activities of P- and V-type H+-ATPases. We found that the total H+-ATPase activity of their plumes was approximately 14 mol h¡1 g¡1 wet weight, and that of their roots was between 5 and 7 mol h¡1 g¡1 wet weight. These activities were more than ten times lower than those measured in R. pachyptila. We suggest that seep tubeworms might use passive channels to eliminate protons across their roots, in
Communicated by M. Kühl. S. Dattagupta (&) · M. Redding · K. Luley · C. Fisher Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA e-mail: [email protected] Present Address: S. Dattagupta Courant Research Centre Geobiology, Georg- August- Universität Göttingen, 370077 Göttingen, Germany
addition to ATP-dependant proton pumps located in their plumes and roots. In addition, we found strong diVerences between the types of ATPase activities in the plumes of L. luymesi and S. jonesi. While the H+-ATPase activity of L. luymesi plumes is dominated by P-type ATPases, S. jonesi has an unusually high activity of V-type H+-ATPases. We suggest that S. jonesi relies on its high V-type H+ATPase activity to drive carbon dioxide uptake across its plume surface. L. luymesi, on the other hand, might rely partially on bicarbonate uptake across its root.
Introduction All living organisms maintain ionic homeostasis using membrane transport processes. Transport ATPases, which couple the energy derived from ATP hydrolysis to drive transport of solutes against their electrochemical gradients, are a ubiquitous type of membrane transport protein (Pedersen 1982). They are generally of three diVerent categories: P-, V-, and F-type ATPases (Van Winkle 1999). P-type ATPases, named so because they are temporarily phosphorylated during their transport c
Data Loading...
