Nagata, T. ORI, University of Tokyo, 81-3-5351-6461
Kirchman, D. CMS, University of Delaware, 302-645-4028

 
ROLE OF LIPOSOME-LIKE PARTICLES IN THE PRESERVATION OF PROTEINS IN SEAWATER
 
Recent studies have suggested that bacterial membrane proteins (porins) and a cell wall component (peptidoglycan) account for a large fraction of high-molecular-weight dissolved organic matter (HMW-DOM) in a variety of oceanic environments including deep waters. These new findings have substantially stimulated interest among investigators in the mechanisms underlying the preservation of detrital biopolymers derived from bacteria. The purpose of this presentation is to review experimental data demonstrating that proteins associated with liposome-like particles (phospholipid vesicles with an aqueous phase interior) are less labile than free proteins. Different types of associations including adsorption to the outer surface of particles, entrapment inside liposomes, and integration within lipid bilayers all impede degradation of proteins, probably because proteins are sterically protected from rapid ectoenzymatic attack in seawater. We also point out that liposome-like particles consisting of bacterial membrane and wall components can be abundantly produced during bacterial death caused by protist grazing and viral infection. Preservation by liposomes of proteins and other DOM appears to be important in the formation of semi-labile and refractory DOM in oceanic waters.
 
Day: Tuesday, Feb. 2
Time: 12:00 - 12:15pm
Location: Eldorado Hotel
 
Code: CS56TU1200E