Sinsabaugh, R. University of Toledo, rsinsab@uoft02.utoledo.edu
Foreman, C. University of Toledo, cforema@uoft02.utoledo.edu
Yeager, P. University of Toledo, pyeager@uoft02.utoledo.edu

 
GLYCOSIDASES, PEPTIDASES, AND DISSOLVED ORGANIC MATTER (DOM) PROCESSING
 
The consumption of DOM by bacteria is mediated by ectoenzymes. In planktonic systems, the most widely measured ectoenzymes are glycosidases and peptidases. Activities per unit production and glycosidase:peptidase activity ratios have been used for cross-system comparisons but the interpretation of these measures in terms of DOM processing needs further clarification. In broad terms, glycosidases and peptidases differ in pH optima, kinetic parameters and regulation, but both types of activity can correlate with bacterial productivity. Pooling available biochemical and ecological information, we propose two hypotheses. First, the predominance of aminopeptidase activities with preferences for hydrophobic and basic amino acid side chains reflects the importance of peptidoglycan synthesis and degradation across systems. Second, the kinetic and regulatory characteristics of glycosidases suggest that saccharides are a highly sought but dynamic resource; high activities reflect a trophic link to primary production or to the availability of newly senescent organic matter.
 
Day: Tuesday, Feb. 2
Time: 12:15 - 12:30pm
Location: Eldorado Hotel
 
Code: CS56TU1215E