Gut bacteria can modulate locomotion in female Drosophila, according to a study published online in Nature this week. Drosophila without a gut microbiome demonstrated increased walking speed and duration of walking bouts compared to flies harbouring a microbial community. The authors identify the enzyme xylose isomerase as being important for the bacterial effect on locomotion.
Recent studies suggest that the intestinal microbiome regulates developmental and functional features of the nervous system in animal models. However, the effects of gut bacteria on the neuromodulators and neuronal circuits involved in locomotion remain poorly understood.
Catherine Schretter and colleagues used the fruit fly, Drosophila melanogaster, to explore host-microbiome interactions that contribute to locomotor behaviour. Locomotion was examined in the presence and absence (through rearing or treatment with antibiotics) of gut bacteria. In comparison to conventionally reared insects, female fruit flies without a microbiota displayed increases in average walking speed and length of bouts of walking, as well as decreased average pause length between bouts.
The authors also examined whether locomotion performance was affected differently by individual bacterial species. They found that colonization with specific bacteria, including Lactobacillus brevis (which is normally found in the fruit fly microbiome) was sufficient to correct speed and daily activity deficits. They determined that the enzyme xylose isomerase — which is found in L. brevis — is important for controlling locomotor behaviour, and suggest that this may occur via the modulation of key carbohydrates such as trehalose.
The authors note that further work is needed to identify the exact neurons and neuronal mechanisms involved. It would also be important to clarify the sex-specific aspects of these microbial effects on locomotion, they argue.