RESUMEN
PURPOSE: Skeletal muscle glycogen is a determinant of endurance capacity for some athletes. Ginger is well known to possess nutritional effects, such as anti-diabetic effects. We hypothesized that ginger extract (GE) ingestion increases skeletal muscle glycogen by enhancing fat oxidation. Thus, we investigated the effect of GE ingestion on exercise capacity, skeletal muscle glycogen, and certain blood metabolites in exercised rats. METHODS: First, we evaluated the influence of GE ingestion on body weight and elevation of exercise performance in rats fed with different volumes of GE. Next, we measured the skeletal muscle glycogen content and free fatty acid (FFA) levels in GE-fed rats. Finally, we demonstrated that GE ingestion contributes to endurance capacity during intermittent exercise to exhaustion. RESULTS: We confirmed that GE ingestion increased exercise performance (p<0.05) and elevated the skeletal muscle glycogen content compared to the non- GE-fed (CE, control exercise) group before exercise (Soleus: p<0.01, Plantaris: p<0.01, Gastrocnemius: p<0.05). Blood FFA levels in the GE group were significantly higher than those in the CE group after exercise (p<0.05). Moreover, we demonstrated that exercise capacity was maintained in the CE group during intermittent exercise (p<0.05). CONCLUSION: These findings indicate that GE ingestion increases skeletal muscle glycogen content and exercise performance through the upregulation of fat oxidation.
RESUMEN
A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable gamma-cyano-alpha-aminobutyric acid synthase. The enzyme was purified and characterized. The purified enzyme has a molecular mass of approximately 180 kDa and consists of four identical subunits. It was stable in the pH range of 6.0 to 10.5 and up to 60 degrees C. The enzyme catalyzed the gamma-replacement reaction of O-acetyl-L-homo-serine with cyanide ions. The gene encoding the gamma-cyano-alpha-aminobutyric acid synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the gamma-cyano-alpha-aminobutyric acid synthase from the bacterium is O-acetyl-L-homoserine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, was introduced into Escherichia coli JM109. The transformed E. coli cells overexpressed gamma-cyano-alpha-aminobutyric acid synthase. The heat stable gamma-cyano-alpha-aminobutyric acid synthase can be applied to the synthesis of [5-11C]L-glutamic acid used as a tracer for positron emission tomography.
