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Chemical Senses Advance Access

Published: Tue, 13 Mar 2018 00:00:00 GMT

Last Build Date: Tue, 13 Mar 2018 01:43:58 GMT


The Role of the Sucrose-Responsive IR60b Neuron for Drosophila melanogaster: A Hypothesis

Tue, 13 Mar 2018 00:00:00 GMT

In a recent paper, Joseph and colleagues (Joseph et al., 2017) have characterized an IR60b receptor-expressing neuron in Drosophila. They showed that it responds to sucrose and serves to limit sucrose consumption, and proposed that it may thereby act to prevent overfeeding. Here, we propose an alternative hypothesis for the functional role of sucrose feeding control, and for how this limitation of sucrose uptake is accomplished. Adult fruit flies feed by excreting saliva onto the food, and imbibing the predigested liquefied food, or by filling the crop, where the food is predigested. Enzymes in the saliva hydrolyze starch and disaccharides into absorbable monosaccharides. Premature ingestion into the midgut would not give the enzymes in the saliva enough time to predigest the food. Thus, IR60b neurons might serve as a sensor to monitor the digestive state of external food or crop content: when disaccharides (sucrose) concentration is high, ingestion to the gut is inhibited, keeping a low concentration of starch and disaccharides in the midgut.

Re-test reliability of gustatory testing and introduction of the sensitive Taste-Drop-Test

Mon, 12 Mar 2018 00:00:00 GMT

The sense of taste holds a key integrate role in assessing the flavour of food before swallowing is initiated. If the expectations for taste are not met, palatability and pleasure of the food can decrease. In patients suffering from taste disorders, this may impair appetite and nutritional state. Testing gustatory function can be important for diagnostics and assessment of treatment effects. However, the gustatory tests applied are required to be both sensitive and reliable.In this study, we investigate the re-test validity of popular Taste Strips gustatory test for gustatory screening. Furthermore, we introduce a new sensitive Taste-Drop-Test, which was found to be superior for detecting a more accurate measure of tastant sensitivity.