Peer Teaching Increases Knowledge and Changes Perceptions about Genetically Modified Crops in Non-Science Major Undergraduates.

We analyzed effects of peer teaching on non-science major undergraduates' knowledge, perceptions, and opinions about genetically modified (GM) crops and their use in agriculture. Undergraduates enrolled in an introductory nonmajors biology course participated in a service-learning program (SLP) in which they acted as cross-age peer teachers to high school students, teaching about the role of genetics in crop improvement through traditional breeding and GM approaches. Using pre/postassessments, we found that undergraduates' opinions shifted to favor the use of GM organisms (GMOs) in agriculture after SLP participation, rising from 46 to 97%. Perceptions about risks and benefits of GMOs also shifted from 43% stating that GMOs are harmful or suspect to no students describing GMOs in that way. Knowledge about GMOs became more accurate after SLP participation. There were significant correlations between students who had negative perceptions of GMOs and negative opinions or inaccurate knowledge about them. Students recognized the effect of peer teaching on their knowledge and perceptions, identifying the repeated peer teaching as an important factor in knowledge gain. Our results suggest students developed an informed opinion about the use of GMOs through first learning the science of genetic engineering and then teaching this information to younger students.

Increased temperature accelerates glycogen synthesis and delays fatigue in isolated mouse muscle during repeated contractions.

AIM: Elevated glycogen content in muscle delays fatigue during exercise. We examined if increasing muscle temperature during recovery from exercise affects glycogen synthesis and muscle performance during a subsequent bout of exercise. METHODS: Isolated mouse extensor digitorum longus muscles were stimulated electrically to perform repeated tetanic contractions until force decreased to 40% of initial at 25°C. Thereafter, muscles recovered for 120 minutes at 25°C (control), 120 minutes at 35°C or 60 minutes at 35°C followed by 60 minutes at 25°C. After recovery, muscles were again stimulated to fatigue at 25°C. RESULTS: In the control group, the number of contractions in the second run was slightly less than during the first run (92 ± 5%). Following recovery for 120 minutes at 35°C, the number of contractions was similar to the first run (98 ± 6%). Allowing recovery for 120 minutes at 35°C in the presence of the antioxidant N-acetylcysteine also did not alter the number of contractions in the second run (98 ± 3%). However, recovery for 60 minutes at 35°C followed by 60 minutes at 25°C resulted in an increase in the number of contractions during the second run (110 ± 2%, P < .001). Incorporation of [14 C]glucose into glycogen (glycogen synthesis) during recovery was 1.7-fold higher at 35°C vs 25°C (1.44 ± 0.08 µmol (30 min)-1  (g wet muscle)-1 vs 0.84 ± 0.04; P < .001). CONCLUSION: These data demonstrate that, under the conditions studied, elevating muscle temperature for 60 minutes following a bout of repeated contractions delays muscle fatigue during a subsequent bout of repeated contractions and this is associated with enhanced glycogen synthesis in isolated muscle.