Date of Completion

2015

Document Type

Honors College Thesis

Department

Biology

Type of Thesis

Honors College, College of Arts and Science Honors

First Advisor

Jim O. Vigoreaux

Abstract

Ageing is a complex process that generally is considered as the loss of function over time. Sarcopenia is the age-related loss of muscle function that can cause a variety of difficulties late in life. Finding nutritional supplements to delay sarcopenia is therefore valuable. beta-Hydroxy beta-methyl butyrate (HMB) has been theorized to be a potential supplement to delay sarcopenia. HMB previously has been shown to delay the loss of flight ability in Drosophila melanogaster and to extend lifespan. The molecular mechanism for either of these effects has yet to be established. This study used the GAL4/UAS system to create a constitutively active S6K (a signaling molecule in the Target of rapamycin (TOR) pathway) strain of Drosophila. S6K was selected because of its role stimulating protein synthesis when phosphorylated by TOR. Its expression was primarily driven in the muscle using the 24B promoter because of the HMB’s effect previously seen on flight ability (a proxy for muscle function). HMB supplementation in this strain did not show a statistically significant delay in the loss of flight ability. Two of the control lines did show a statistically significant delay in the loss of flight ability (24B/GAL4 Males p=0.0387, week 4) (UAS/dS6KSTDETE p=0.0215, week 3). HMB supplementation showed no effect in any test on lifespan. To test if either of the two effect of HMB were due an indirect effect of HMB causing diminished food intake, this study also made a preliminary attempt to determine if HMB causes differential food intake (a control not yet previously done). There was evidence that HMB affects feeding habits under certain experimental conditions (6 hour starved male flies, p = 0.0250). The results of this study suggest that HMB does work through TOR/S6K to delay the loss of flight ability and does not suggest an effect of HMB on lifespan; differential food intake could be a compounding variable in these results and future work should continue to address this.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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