MASL Research Studies


Molecular and Applied Sciences Laboratory

Recent MASL research studies include:

  • Effects of different proteins or L-leucine supplementation on resistance training variables
  • Effects of graded whey protein supplementation on resistance training adaptations
  • Physiology behind low versus high hypertrophic responders
  • Effects of exercise training on LINE-1 “jumping gene” activity in skeletal muscle”
  • Effects of dietary milk exosomes on skeletal muscle physiology
Effects of different proteins or L-leucine supplementation on resistance training variables

Data from Mobley et al. (Nutrients, 2017) demonstrating that whey protein concentrate supplementation, hydrolyzed whey protein concentrate supplementation, soy protein concentrate supplementation, and L-leucine with maltodextrinelicited similar increases in back squat strength and body composition in previously untrained college-aged males following a 12-week intervention.

Pre/Post 3-Rep Max dataPre/Post total fat mass data

Pre/Post total body muscle mass and VL thickness data

Effects of graded whey protein supplementation on resistance training adaptations

Data from Haun et al. (Frontiers Nutr, 2018) demonstrating that weekly graded whey protein concentrate supplementation elicited superior improvements in body composition compared to a standard dosing strategy or a maltodextrinplacebo in previously trained college-aged males following a 6-week intervention.

ANCOVA results DXA lean body mass pre, mid, and post for control group, whey group, and graded whey group DXA Fat mass pre, mid, and post for control, whey, and graded whey

Physiology behind low versus high hypertrophic responders

Data from Mobley et al. (PLOS One, 2018) demonstrating that the mid-thigh muscle clearly grows in some previously untrained college-aged males following 12 weeks of resistance training (delta = post-training values after subtracting out pre-training values; positive values indicate growth, and “HI” responders showed the most growth versus “MOD” or “LOW” responders).  The right pictures are representative ultrasound images prior to and following training from a LOW and HI responder.  Under these images shows that total muscle RNA (i.e., ribosome content) clearly increases in HI versus LOW responders supporting the hypothesis that muscle ribosomes are critical for muscle growth during resistance training.

delta VL thickness Low pre/post and High pre/post Muscle RNA low, moderate, and high

Effects of exercise training on LINE-1 “jumping gene” activity in skeletal muscle”

Data from Romero et al. (AJP Cell Physiol, 2018) demonstrating that skeletal muscle mRNA expression of the LINE-1 “jumping gene” is decreased previously untrained college-aged males following 12 weeks of resistance training.  Also shown are: 1) LINE-1 promoter methylation increasing with training (indicating the mechanism which down-regulates LINE-1 mRNA), and 2) a decrease in muscle reverse transcriptase (or RT) activity. Collectively, these are the first results to demonstrate that exercise can downregulate this putative “genetic parasite” in muscle.  Implications of these data are that lifelong exercise may preserve muscle health through this mechanism, and current ongoing studies in Dr. Roberts’ laboratory are examining these markers in younger and older humans.

LINE-1 mRNA and promoter methylation data week 0 and week 12 RT activity data week 0 and week 12

Effects of dietary milk exosomes on skeletal muscle physiology

Data from Parry, Mobley et al. (FrontiersPhysiol, under review) demonstrating in rats that feeding sonicated-modified milk exosomes to young rats for 4 weeks (ERD rats) increases muscle fiber cross-sectional area (fCSA) and muscle ribosome content.  ERS rats consumed a similar milk-based diet which was not disrupted through sonication.  These data imply that, not only is milk a muscle-building food due to its protein content, but that milk contains bioactives(e.g., exosomes) which may affect muscle physiology.  This project is being performed in collaboration with Dr. Andreas Kavazis, Dr. Janos Zempleni (University of Nebraska-Lincoln), and Dr. John McCarthy (University of Kentucky).

right gastric fCSA and total RNA dystrophin data

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