Meeting Abstract
The apical, brush border membrane (bbm) of vertebrate small intestine contains hydrolases that break down dietary polymers to monomers that are absorbed. The study of activities of the intestinal enzymes across different taxa, and of their phenotypic flexibility under different ecological scenarios, has produced general adaptive/evolutionary patterns that have received a good amount of attention. However, information on amounts of enzyme proteins at bbms is still scarce. Therefore, we explored relative abundance of intestinal enzymes in bbm, and their relationship to function, i.e. activities, in four birds, the granivorous Taeniopygia guttata, the granivorous/ omnivorous Passer domesticus and Gallus gallus, the insectivorous Sturnus vulgaris and the omnivorous Mus musculus and Rattus norvegicus. We predicted (1) that proteases and lipases would be proportionally more abundant in the insectivore, and carbohydrases proportionally more abundant in starch consumers, and (2) that the amount of enzymes in bbms would be proportional to their activities. Using intestinal tissue of four individuals of each species we prepared bbm isolates. Proteins were solubilized, digested and chromatographically separated. Peptides were analyzed by nano LC-MS/MS. MS/MS data were used to search against Uniprot and RefSeq databases. Hydrolases (i.e. their spectra) represented between 4 and 11% of the total protein (total spectra) detected. In agreement with our predictions, starlings had a higher proportion of intestinal proteases and lipases and less carbohydrases than granivorous/omnivorous species, and relative quantities of enzymes were proportional to assayed activities. Supported by NSF-IOS1354893 & CONICET-PIP0834 &UNSL2-0814.
