| 2142 Using drosophila to evaluate taste preference for xylitol | ||
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C.R. JOHNSON, and D. MORTON, Oregon Health & Science University, Portland, USA Objective: The mechanism of taste transduction is highly conserved between mammals and insects. We used Drosophila melanogaster to evaluate the taste transduction mechanisms involved in sensing and responding to the artificial sweetener xylitol compared to sucrose. Methods: The sugar alcohol, xylitol has been reported to have similar sweetness intensity to sucrose. We used a simple neural reflex to compare its effects to sucrose. Flies have taste receptors in their feet, which when stimulated initiate a proboscis extension reflex. Groups of flies were tested (N=5) with various concentrations of a sugar solution applied to their tarsal taste receptors and the proboscis extension response was recorded as follows: no response=0, half response=1, full response=2. Curiously, although flies responded mildly to xylitol during this reflex test they appeared not to ingest it when given the opportunity to drink. To test this more quantitatively we performed a feeding preference assay allowing groups of flies (N=5) to drink colored solutions of sucrose, xylitol or water then counting the colored bellies to test the flies' sucrose/xylitol preference. Data was analyzed using ANOVA one-way test (á=0.05). Results: Positive proboscis reflex responses were recorded for both sucrose and xylitol in a dose-response manner. However, both the sensitivity and the maximal response to xylitol were significantly lower compared to sucrose (p<.001). The results of the preference assay confirmed that flies were reluctant to ingest xylitol when given the choice between xylitol and sucrose or xylitol and water (p<.0001). Conclusions: Drosophila's apparent avoidance of xylitol may indicate some metabolic aversion not readily detectable by humans. The simplicity of these tests suggests that Drosophila is a good model for evaluating the effectiveness of sugar-free sweeteners as flies appear to be able to discriminate between sweeteners more effectively than humans. Acknowledgements: This work was supported by grants from OHSU and NIH. | ||
| Seq #226 - Nutrition Posters 3:30 PM-4:45 PM, Friday, March 23, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
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