RICHARDS, C. T.; BIEWENER, A. A.; Harvard University; Harvard University: In vivo dynamic force-length properties in the Xenopus laevis plantaris muscle In vivo plantaris activation and length were recorded by sonomicrometry and electromyography (EMG). Measurements of force were obtained from a calibrated stain gauge transducer fastened to the Achilles tendon. Peak force and strain were […]

DIMOULAS, PM; HENRY, H; RUBENSON, J; MARSH, RL; Northeastern University; Northeastern University; Northeastern University; Northeastern University: Homogenous activation patterns of the anatomically compartmentalized semimembranosus muscle in Bufo marinus Locomotor muscles in vertebrates may be compartmentalized in several ways: anatomically, neuromuscularly, and functionally. We examined whether the anatomically compartmentalized semimembranosus muscle (SM) in the toad Bufo […]

CARR, JA; ELLERBY, D; HOOGENDYK, TA; RUBENSON, J; MARSH, RL; Northeastern University; Northeastern University; Northeastern University; Northeastern University; Northeastern University: Differential Strain in an Architecturally Complex Muscle Understanding the mechanical function of muscles with extensive origins and insertions is challenging. The Iliotibialis lateralis pars postacetabularis (ILPO) is the largest muscle in the hindlimb of the […]

KELLEY, KM; GALIMA, MM; REYES, JA; SAK, K; SMOLKO, S; BAKER, ME; LOWE, CG; CA State Univ. Long Beach; CA State Univ. Long Beach; CA State Univ. Long Beach; CA State Univ. Long Beach; CA State Univ. Long Beach; Univ. CA San Diego; CA Sate Univ. Long Beach; : Temporal Relationships in the Stress- and […]

WADA, H.; BREUNER, C.W.; WINGFIELD, J.C.; MOORE, I.T.; University of Texas, Austin; University of Texas, Austin; University of Washington; Virginia Polytechnic Institute and State University: Stress responses in equatorial sparrows: comparing tropical and temperate Zonotrichia Comparisons between sister species are useful ways to test the role of environment as a selection pressure shaping the adrenocortical […]

NUNEZ, B. Scott; The University of Texas Marine Science Institute: Stress and reproduction in the Atlantic croaker (Micropogonias undulatus) Steroids are lipophilic hormones that impinge upon virtually every physiological process in vertebrates. The synthesis of the correct type and amount of steroid at the proper time requires the precise regulation of the steroidogenic acute regulatory […]

APPLEBAUM, Scott; NUNEZ, Scott; University of Texas at Austin; University of Texas at Austin: Mechanisms of stress-induced changes in ovarian steroidogenesis in the Atlantic croaker. Stress can rapidly alter plasma sex steroid concentrations in a variety of vertebrates including teleosts. The mechanisms precipitating these changes are unclear; however, a disruption of steroidogenesis is likely involved. […]

BUSCH, D. S. *; BOYD, E.; WINGFIELD, J. C.; University of Washington, Seattle: Chronic, acute pulses of corticosterone alter body condition and timing of molt Corticosterone (B) can be detrimental if it is maintained at or close to maximal stress-induced levels. Animals release high levels of B in response to stressful events and modulate the […]

KITAYSKY, A.S.; IAB and Dept. of Biology and Wildlife, Univ. of Alaska, Fairbanks: Activation and suppression of the adrenal axis in food-limited chicks In several seabirds, nutritional state of a nest-bound chick is negatively correlated with the activity of its hypothalamus-pituitary-adrenal (HPA) axis. Increased corticosterone (cort) secretion has been shown to facilitate changes in behavior […]

BENOWITZ-FREDERICKS, Morgan; KITAYSKY, Alexander S.; HATCH, Scott A.; Univ. Alaska, Fairbanks; Univ. Washington, Seattle; Univ. Alaska, Fairbanks; U.S. Geological Survey, Alaska Science Center : Yolk androgens in Black-legged kittiwakes: Consequences of food supplementation Black-legged kittiwakes are seabirds that frequently face food shortages during reproduction. Siblicide resulting in loss of the beta chick reduces competition among […]