Premium
Determination Of Citrate Synthase And Phosphoenolpyruvate Carboxykinase Expression In Eared Grebes ( Podiceps nigricollis ) Preparing for Migration
Author(s) -
Thorngren Valerie,
Brent Allman,
Luu Sylvester,
Bergen Amy,
Grey Chyna,
Ellis Hugh,
Provost Joseph
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.884.53
Subject(s) - phosphoenolpyruvate carboxykinase , citrate synthase , gluconeogenesis , biology , enzyme , phosphoenolpyruvate carboxylase , mitochondrion , biochemistry
Citrate Synthase (CS), a key regulatory enzyme in the Krebs cycle, and phosphoenolpyruvate carboxykinase (PEPCK), a critical marker enzyme of gluconeogenesis, are used as quantitative indicators of metabolic activity. The eared grebe ( Podiceps nigricollis ) prepares to migrate on a few select lakes in the western United States. Studies showing basal metabolic rate in grebes seems unaffected by changes in organ size as grebes switch from a non‐migratory to a migratory mode. However, the metabolic intensity of these organs seems to change as grebes prepare to depart. CS activity has been found to increase from 110.96 ± 26.18 µmol g ‐1 min ‐1 to 169.92 ± 31.24 µmol g ‐1 min ‐1 in grebes shortly before migratory departure, an increase exceeding 50%. We are interested in how CS increases rapidly in these birds, whether it is achieved by increasing activity, mitochondrial density, or CS expression in existing mitochondria. We are also interested in the extent to which these pre‐migratory birds might be increasing gluconeogenesis prior to flight. We identify changes in overall CS expression using immunoanalysis in homogenized tissue and quantitatively measure the level of mitochondrial and cytosolic markers in each bird. We also determine PEPCK specific activity in liver of these birds to identify potential gluconeogenic shifts in preparation for migration. This evidence suggests that either mitochondrial density or mitochondrial expression in organs increases in preparation for migration.