Journal: bioRxiv

Article Title: Uracil-Driven ROS signals activate larval TrpA1-B neurons to prime the Drosophila adult gustatory response to bacterial signal

doi: 10.64898/2025.12.22.695905

Figure Lengend Snippet: ( A ) Live L. brevis are necessary and sufficient to prime the larvae. PER index of w- flies to control solutions of sucrose and sucrose + PGN from E. coli K12 (PGN). Larvae from sterilized eggs were exposed to the different treatments and the resulting adults raised on antibiotics-containing media. ( B ) Uracil is necessary and sufficient to prime the larvae. PER index of w-flies to control solutions of sucrose and sucrose + PGN from E. coli K12 at 200µg/mL (PGN200). Larvae were monoassociated with bacterial strains, with LB media or with LB media containing uracil. The resulting adults were raised on antibiotics-containing media. (C) The Duox enzyme is necessary in enterocytes for the priming. PER index to solutions of sucrose and sucrose + PGN (PGN200) of GAL4 ( mex - GAL4 /+) and UAS (+/UAS-Duox_IR ) control flies as well as animals with the Duox transcript impaired via RNAi in enterocytes ( mex - GAL4 / UAS-Duox_IR ). Larvae were raised on conventional media and the resulting adults raised on antibiotics-containing media. ( D ) Graphical representation of the life periods during which flies are shifted from 18 ° C to 29 ° C for a stage-dependent RNAi assay. The ubiquitously expressed Tub-G80 ts , that inhibits the activity of GAL4, is temperature sensitive: the GAL4 inhibitor is active at 18 ° C (green) and inactivated at 29 ° C (black), its inactivation allows the expression of any UAS . In the case of mex - GAL4 ; TubG80 ts /UAS-Duox_IR , at 18°C the Duox transcripts will not be impaired ( Duox ) while it will be at 29°C (). ( E ) Duox activity in enterocytes is necessary during the larval life for priming. PER index to solutions of sucrose and sucrose + PGN (PGN200) of mex-GAL4; TubG80 ts /UAS-Duox_IR flies with the Duox transcript impaired all-life long, only during the larval stages or only during the adult stage. Larvae were raised on conventional media and the resulting adults raised on antibiotics-containing media. ( F ) Reducing the amount of ROS impairs the priming. PER index to solutions of sucrose and sucrose + PGN (PGN200) of UAS (+/UAS-Catalase ) control flies as well as animals with the Catalase over-expressed in enterocytes ( mex-GAL4/UAS-Catalase ). Larvae were raised on conventional media and the resulting adults raised on antibiotics-containing media. ( G ) H 2 O 2 supplementation to larvae is not sufficient to prime while vitamin C addition during the larval life prevents it. PER index to solutions of sucrose + PGN (PGN200) of w - flies. Larvae were raised on conventional media with or without vitamin C (0.2 mg/mL) or on antibiotics-containing media with or without H 2 O 2 (1%). All the resulting adults were raised on antibiotics-containing media. Labellar PER was measured to 1 mM sucrose plus or minus PGN. The PER index is calculated as the percentage of flies tested that responded with a PER to the stimulation ± 95% confidence interval (CI). A PER value of 1 means that 100% of the tested flies extended their proboscis following contact with the mixture, a value of 0.2 means that 20% of the animals extended their proboscis. The number of tested flies (n) is indicated on top of each bar. For each condition, at least 3 groups with a minimum of 10 flies per group were used. Each independent group is represented as an open circle. ns indicates p>0.05, * indicates p<0.05, ** indicates p<0.01, *** indicates p<0.001, **** indicates p<0.0001 Fisher Exact Test. Further details can be found in the detailed lines, conditions and, statistics for the figure section.

Article Snippet: PGN is E. coli K12: Invivogen, catalog code #tlrl-kipgn.

Techniques: Control, RNAi Assay, Activity Assay, Expressing