Internal states drive nutrient homeostasis by modulating exploration-exploitation trade-off
- Champalimaud Centre for the Unknown, Portugal
- Imperial College London, United Kingdom
- MRC Clinical Sciences Centre, United Kingdom
Figures
Figure 1 with 1 supplement
Automated monitoring of nutrient choices using image-based tracking.
(A) Schematic of the image-based tracking setup. (B) Schematic of the foraging arena, containing an inner flat circular area with 9 sucrose (carbohydrate source) and 9 yeast (amino acid source) …
Figure 1—figure supplement 1
Ground-truthing of behavior.
(A) Normalized histogram of head speed of amino acid-deprived mated females (AA- diet) from two independent video tracking experiments: orange lines represent data obtained from an assay in which …
Figure 2 with 3 supplements
Flies increase yeast feeding and micromovements in response to amino acid challenges and mating.
(A) Graphical representation of the five internal states tested and the resulting reproductive output as reported by Piper et al. (2013), all flies were pre-fed during three days with the indicated …
Figure 2—figure supplement 1
flyPAD setup, sucrose sips and yeast sips dynamics.
(A) Schematic of flyPAD arena, adapted from (Itskov et al., 2014). (B) Effect of internal states on the number of sucrose sips. Experimental groups are: Virgin (open circles) and mated (closed …
Figure 2—figure supplement 2
Sucrose micromovements.
Effect of internal states on the total duration of sucrose micromovements obtained from the video tracking assay.
Figure 2—figure supplement 3
Fraction of yeast non-eaters and coefficient of variation for yeast micromovements.
(A) Effect of internal states on the proportion of yeast non-eaters. A yeast non-eater is a fly for which the total duration of yeast visits was lower than 1 min. Significance was tested by a 2 x 2 …
Figure 3 with 1 supplement
Metabolic state and mating modulate the probability of stopping at a yeast patch and leaving it.
(A) Effect of internal states on the total duration of yeast visits. Experimental groups are the ones shown in Figure 2: Mated (filled circles) and virgin (open circles) females pre-fed three types …
Figure 3—figure supplement 1
Yeast encounters and probability of leaving.
(A) Effect of internal states on the absolute number of yeast encounters. (B) Complementary cumulative distribution function for yeast visit durations. Single dots represent one yeast visit. All …
Figure 4 with 3 supplements
The lack of dietary AAs increases exploitation and local exploration of yeast patches.
(A) Rolling median of the total duration of yeast visits using a 5 min window and a step of 4 min for flies pre-fed a suboptimal diet (yellow) or AA− diet (red). (B) Effect of AA deprivation on the …
Figure 4—figure supplement 1
Yeast visits dynamics and latency.
(A,B) Rolling median of the total duration of yeast visits (A) and average duration of yeast visits (B) using a 5 min window and a step of 4 min for flies fed a AA+ rich diet (purple), AA+ …
Figure 4—figure supplement 2
No effect in local exploration of yeast patches for flies pre-fed a suboptimal diet.
(A) Effect of AA challenges on the average minimum distance to the center of yeast patches, during a yeast visit. (B) Effect of AA challenges on the body centroid speed, during a yeast visit. (C) …
Figure 4—figure supplement 3
Modulation of yeast feeding program microstructure by AA challenges.
(A) Schematic of feeding program microstructure. Two components of the feeding microstructure can be modulated to reach protein homeostasis: the number of sips inside each feeding burst (blue …
Figure 5 with 1 supplement
Amino acid challenges reduce global exploration and increases revisits to same yeast patch.
(A–C) Effect of internal states on exploratory behavior of mated females pre-fed with an AA rich diet (A), an AA suboptimal diet (B) or an AA− diet (C). Example trajectories show head position …
Figure 5—figure supplement 1
Dynamics of yeast-yeast transitions in single flies.
Ethograms showing the yeast visits for each fly (each row is a single fly) along the 120 min of the video tracking assay, for the indicated condition. Colors indicate if the food patch visited …
Figure 6 with 1 supplement
Flies dynamically adapt their exploitatory and exploratory behavior as their internal AA satiation changes.
(A) Definition of yeast quartiles based on the total duration of yeast micromovements along the two hours of the video tracking assay for an example fly. Arrows indicate start and end points of each …
Figure 6—figure supplement 1
Exploitation parameters in AA-deprived flies revert back to fully-fed values.
(A–C) Exploitation parameters from first yeast quartile (Q1) and fourth yeast quartile (Q4) of AA-deprived mated females compared to the values observed in flies pre-fed a rich and a suboptimal diet …
Figure 7 with 1 supplement
ORs mediate efficient recognition of yeast as an appropriate food source.
(A) Orco1/1 AA-deprived flies spend as much total time visiting yeast as AA-deprived control flies (n = 10–14). (B) Rolling median of the total duration of yeast visits using a 5 min window and a …
Figure 7—figure supplement 1
Yeast dynamics of Orco mutant flies.
Cumulative duration of yeast micromovements. Gray lines correspond to single flies. Thick colored lines indicate median.
Figure 8 with 1 supplement
Octopamine mediates postmating response towards yeast but not internal sensing of AA deprivation state.
(A–C) Effect of the TβhnM18 mutation on the postmating change in foraging parameters, obtained from the video tracking assay after 1 hr: total duration of yeast visits (A), probability of stopping …
Figure 8—figure supplement 1
Octopamine mediates postmating response to yeast.
(A–C) Effect of the TβhnM18mutation on the postmating change in foraging parameters, obtained using the video tracking setup: (A) total duration of yeast visits, (B) probability of stopping at a …
Figure 9
Model of behavioral strategies modulated by internal AA state.
We propose a model in which virgin flies with high internal levels of AAs display low intake mostly ignore yeast patches upon encounter and have a high probability of leaving the yeast patch upon …
Videos
Video 1
Behavior classification during nutrient decisions.
A 20-s-segment of the trajectory depicted in Figure 1C–D, starting on second 40 and following the same color code. The first 7 s of the video are slowed-down 0.5 x, as indicated by the white label …
Tables
Table 1
Composition of holidic medium.
| Ingredient | Stock | Amount per liter | |
|---|---|---|---|
| Gelling agent | Agar | 20 g | |
| Sugar | Sucrose | 17.12 g | |
| Amino acids for 50S200NHUNTaa* | L-isoleucine | 1.82 g | |
| L-leucine | 1.21 g | ||
| L-tyrosine | 0.42 g | ||
| Amino acids for 50S200NYaa* | L-isoleucine | 1.16 g | |
| L-leucine | 1.64 g | ||
| L-tyrosine | 0.84 g | ||
| Metal ions | CaCl2.6H2O | 1000x: 250 g/l | 1 ml |
| CuSO4.5H2O | 1000x: 2.5 g/l | 1 ml | |
| FeSO4.7H2O | 1000x: 25 g/l | 1 ml | |
| MgSO4 (anhydrous) | 1000x: 250 g/l | 1 ml | |
| MnCl2.4H2O | 1000x:1 g/l | 1 ml | |
| ZnSO4.7H2O | 1000x: 25 g/l | 1 ml | |
| Cholesterol | Cholesterol | 20 mg/ml in Ethanol | 15 ml |
| Water | Water (milliQ) | 1 l minus combined volume to be added after autoclaving | |
| Autoclave 15 min at 120ºC. All additions below should be performed using sterile technique | |||
| Amino acids for 50S200NHUNTaa* | Essential amino acid stock solution | 8 g/l L- arginine monohydrochloride 10 g/l L-histidine 19 g/l L- lysine monohydrochloride 8 g/l L-methionine 13 g/l L-phenylalanine 20 g/l L-threonine 5 g/l L-tryptophan 28 g/l L-valine | 60.51 ml |
| Non-essential amino acid stock solution | 35 g/l L-alanine 17 g/l L-asparagine 17 g/l L-aspartic acid sodium salt monohydrate 0.5 g/l L-cysteine hydrochloride 25 g/l L-glutamine 32 g/l glycine 15 g/l L-proline 19 g/l L-serine | 60.51 ml | |
| Sodium glutamate stock solution | 100 g/l L-glutamic acid monosodium salt hydrate | 15.13 ml | |
| Amino acids for 50S200NYaa* | Essential amino acid stock solution | 23.51 g/l L-arginine monohydrochloride 11.21 g/l L-histidine 28.70 g/l L-lysine monohydrochloride 5.62 g/l L-methionine 15.14 g/l L-phenylalanine 21.39 g/l L-threonine 7.27 g/l L-tryptophan 22.12 g/l L-valine | 60.51 ml |
| Non-essential amino acid stock solution | 26.25 g/l L-alanine 13.89 g/l L-asparagine 13.89 g/l L-aspartic acid sodium salt monohydrate 30.09 g/l L-glutamine 17.89 g/l glycine 9.32 g/l L-proline 12.56 g/l L-serine | 60.51 ml | |
| Sodium glutamate stock solution | 100 g/l L-glutamic acid monosodium salt hydrate | 18.21 ml | |
| Cysteine stock solution | 50 g/l L-cysteine hydrochloride | 5.28 ml | |
| Vitamins | Vitamin solution | 125x: 0.1 g/l thiamine hydrochloride 0.05 g/l riboflavin 0.6 g/l nicotinic acid 0.775 g/l Ca pantothenate 0.125 g/l pyridoxine hydrochloride 0.01 g/l biotin | 14 ml |
| Sodium folate | 1000x: 0.5 g/l | 1 ml | |
| Base | Buffer | 10x: 30 ml/l glacial acetic acid 30 g/l KH2PO4 10 g/l NaHCO3 | 100 ml |
| Other nutrients | 125x: 6.25 g/l choline chloride 0.63 g/l myo-inositol 8.13 g/l inosine 7.5 g/l uridine | 8 ml | |
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* To prepare the 50S200NHUNTaa diet, use the values shaded in blue. To prepare the 50S200NYaa diet, use the values shaded in orange.
