Research

The Effect of Orientation of the Rear Legs on the in Vitro Contractile Force of the Gastrocnemius in the American Bullfrog, Lithobates Catesbeianus

The Effect of Orientation of the Rear Legs on the in Vitro Contractile Force of the Gastrocnemius in the American Bullfrog, Lithobates Catesbeianus

The gastrocnemius muscle is the main muscle in the calf that flexes the foot and knee, and partially generates force during a jump. A muscle’s contractile force can be influenced by many factors including muscle thickness, the angle between the muscle body and the muscle fibers (pennation angle), and the length of the muscle fibers. During contraction, the fascicles shorten and rotate to greater pennation angles to generate force for movement. While much is known about the behavior and force generation of individual muscles, it’s less clear how the orientation of the muscle in relation to other bones and muscles affects the generation of force during contraction. Therefore, the focus of this experiment was to determine the orientation, or angle, of the gastrocnemius that would generate the greatest contractile force when stimulated. Four different orientations of the frog gastrocnemius were used to determine which generated the greatest contractile force. In this experiment, we assessed the contractile force generated across leg configurations that would occur during a jump. The muscle was stimulated with an electrode and force from muscle contraction was measured using a force transducer. The results from the overall model showed no significant differences in contractile force among the positions tested (p = 0.071). Using this information can help us understand how frogs generate such great contractile forces. This would be beneficial to understanding the mechanisms underlying jumping in this species, as well as inform future research about contractile force and kinematics that occur during jumping in other species.

Analysis of Variants Associated with Cystic Fibrosis (CFTR) in Relation to the Known Pathogenic Variant DeltaF508

Analysis of Variants Associated with Cystic Fibrosis (CFTR) in Relation to the Known Pathogenic Variant DeltaF508

Cystic Fibrosis (CF) is a genetic disease that affects the thickness of digestive fluids, mucus, and sweat, which often leads to obstructions in body organs ducts. The most common CF mutation is the removal of amino acid phenylalanine at position 508 (deltaF508) on the CFTR gene. On CFTR, there are variants of uncertain significance (VUS) as well as classified variations that may cause similarly negative effects. The missense point variations Q493P, W496R, G500D, and Y515C were VUS when this research project began. The aim of this study was to classify them as harmful, neutral, or beneficial. These variations are non-conservative, meaning that there is a change in the biochemical properties between substituted and original amino acids. A drastic change in the biochemical properties might be detrimental to protein folding and functionality. The variants were assessed through the “sequence-to-structure-to-function” workflow developed by the Prokop lab. Data gathered from several databases were used to determine the variants’ impact on CFTR function by comparing them to all known variants as of October 2019.