Data from: Metabolic and immunological responses of Drosophila melanogaster to dietary restriction and bacterial infection differ substantially between genotypes in a population
Data files
Jan 25, 2025 version files 189.03 KB
-
Dataset.xls
68.10 KB
-
plasticity_index.xls
112.13 KB
-
README.md
8.80 KB
Abstract
To respond to changing environmental conditions, a population may either shift towards better-adapted genotypes or adapt on an individual level. The present work aimed to quantify the relevance of these two processes by comparing the responses of defined Drosophila populations to different stressors. To do this, we infected two homogeneous populations (isofemale lines), which differ significantly in fitness, and a synthetic heterogeneous population with a specific pathogen and/or exposed them to food restriction. Pectobacterium carotovorum was used to infect Drosophila larvae either fed standard or protein-restricted diets. In particular, the two homogeneous groups, which diverged in their fitness, showed considerable differences in all parameters assessed (survivorship, protein and lipid contents, phenol-oxidase activity, and antibacterial rate). Under fully nutritious conditions, larvae of the homogeneous population with low fitness exhibited lower survivorship and protein levels, as well as higher phenol-oxidase activity and antibacterial rate compared with the fitter population. A protein-restricted diet and bacterial infection provoked a decrease in survivorship, and antibacterial rate in most populations. Bacterial infection elicited an opposite response in protein and lipid content in both isofemale lines tested. Interestingly, the heterogeneous population showed a complex response pattern. The response of the heterogeneous population followed the fit genotype in terms of survival and antibacterial activity but followed the unfit genotype in terms of phenol-oxidase activity. In conclusion, our results show that defined genotypes exhibit highly divergent responses to varying stressors that are difficult to predict. Furthermore, the responses of heterogeneous populations do not follow a fixed pattern showing a very high degree of plasticity and differences between different genotypes.
README: Metabolic and immunological responses of Drosophila melanogaster to dietary restriction and bacterial infection differ substantially between genotypes in a population
https://doi.org/10.5061/dryad.4mw6m90cs
Description of the data and file structure
Two isofemale (homogenous) lines were selected for use in the present study based on emergence percentage (survivorship) and referred to as A and B. Line A was the population A that produced the lowest egg-to-adult survival rate, while line B was the population that produced the highest egg-to-adult survival rate of eight isofemale lines tested, as reported in Elkayal et al. (2016).
A heterogeneous population (experimental) was created by mixing the eight isofemale lines altogether as described in The Drosophila Synthetic Population Resource (DSPR, 2021). To assess the effects of protein-restricted diet and/or infection by Pectobacterium carotovorum on the response of the populations A and B (genotypes) and the heterogeneous population (Exp), first instar Drosophila larvae were allowed to develop under four environmental conditions. These conditions were uninfected+standard diet, uninfected+restricted diet, infected+standard diet, and infected+restricted diet. Parameters such as survivorship, protein and lipid contents, phenol-oxidase activity, and antibacterial rate were assessed following exposure. Moreover, the extent of plasticity among isofemale lines (genotypes) and the heterogeneous population, was calculated using the relative distance plasticity index (RDPI) as described in (Valladares et al., 2006).
Files and variables
File: Dataset.xls
Description: we measured the survivorship, lipid and protein contents, phenol-oxidase specific activity and antibacterial activity of Drosophila melanogaster third-instar larvae after exposure to 4 environments. These conditions were as follows: i) standard medium in the absence of Pectobacterium carotovorum (uninfected standard), ii) restricted dietary medium in the absence of P. carotovorum (uninfected restricted), iii) P. carotovorum + standard medium (infected standard), and iv) P. carotovorum + restricted dietary medium (infected restricted). Survivorship was observed as the number of emerged adults out of ten larvae. The lipid and protein contents, phenol-oxidase activity and antibacterial rate were determined spectrophotometrically in the whole body homogenate of D. melanogaster larvae.
Variables
- Population (categorical): we used three populations two homogenous populations (A represents the unfit population and B represents the fit population in terms of percentage emergence) as well as a heterogeneous population (Exp).
- Diet: the populations were exposed to two different diet regimens (standard and protein-restricted diets).
Treatment: the population were exposed to two different treatment conditions called (control and infection with bacteria).
Environment (categorical): by combining treatment conditions and diet, we have exposed the populations to 4 environmental conditions (i) standard medium in the absence of Pectobacterium carotovorum (uninfected standard), ii) restricted dietary medium in the absence of P. carotovorum (uninfected restricted), iii) P. carotovorum + standard medium (infected standard), and iv) P. carotovorum + restricted dietary medium (infected restricted).
Survivor: number of emerged adults/replicate after exposure of D. melanogaster larvae to the environmental conditions tested.
Total: Number of D. melanogaster larvae tested in each replicate of the emergence experiment.
Emergence (proportion): number of emerged adults/replicate out of 10 D. melanogaster larvae tested.
trans_emergence: transformation of emergence = (Arcsin(Square root(emergence)).
Lipid content (continuous): the content of lipid in D. melanogaster larval homogenate (mg/g body), was measured using a spectrophotometer after 4-day exposure to the environments.
Protein contents (mg/g body) (continuous): the content of protein in D. melanogaster larval homogenate (mg/g body) was measured using a spectrophotometer after 4-day exposure of the environments.
Phenol-oxidase specific activity (continuous): It was measured in D. melanogaster larval homogenate after 4-day exposure to the environments. One unit is the amount of enzyme required to increase the absorbance at 490 nm by 0.001 min−1 divided by the protein content (mg) determined in the sample (Unit/mg.min)
Antibacterial rate (proportion): It was measured in D. melanogaster larval homogenate after 4-day exposure to the environments. The antibacterial rate was expressed as a rate, number of cell forming units in the P. carotovorum suspension incubated for 2h with whole-body homogenate of Drosophila larvae (95:5 v/v) in relation to the control measurement. The control contains Ringer’s solution instead of whole-body homogenate.
trans_antibacterial rate : transformation of antibacterial rate = (Arcsin(Square root(antibacterial rate)).
File: plasticity_index.xlsx
Description: Three variables (two independent variables: genotype and environment) and one dependent variable (emergence, protein content, lipid content, Phenol-oxidase specific activity or antibacterial rate). we used 7 replicates for the emergence experiment and 5 replicates for the other experiments.
Variables
- Environment_1 or environment_2 (categorical): it represents the type of environmental conditions, in which we exposed the different genotypes. It contains 4 categories: (i) control condition with standard medium (control standard), ii) control condition with restricted dietary medium (control restricted), iii) infection with P. carotovorum + standard medium (infected standard), and iv) infection with P. carotovorum + restricted dietary medium (infected restricted).
- Genotype (categorical): we used three categories, two homogenous populations (A represents the unfit genotype and B represents the fit genotype in terms of percentage emergence) as well as one heterogeneous population (Exp).
- Survivorship_1 and survivorship_2 (proportion): number of emerged adults/replicate out of 10 D. melanogaster larvae tested in different environments (environment_1 or environment_2).
- Protein content_1 and protein content_2 (continuous): the content of protein in D. melanogaster larval homogenate (mg/g body) was measured using a spectrophotometer after 4-day exposure to different environments (environment_1 or environment_2).
- Lipid content_1 and lipid content_2 (continuous): the content of lipid in D. melanogaster larval homogenate (mg/g body), was measured using a spectrophotometer after 4-day exposure to the environments (environment_1 or environment_2).
- Phenoloxidase specific activity_1 and phenoloxidase specific activity_2 (continuous): It was measured in D. melanogaster larval homogenate (Unit/mg.min) after 4-day exposure to the different environments (environment_1 or environment_2).
- Antibacterial rate_1 and antibacterial rate_2 (proportion): It was measured in D. melanogaster larval homogenate after 4-day exposure to different environments (environment_1 or environment_2). The antibacterial rate was expressed as a rate, number of cell forming units in the P. carotovorum suspension incubated for 2h with whole-body homogenate of Drosophila larvae (95:5 v/v) in relation to the control measurement. The control contains Ringer’s solution instead of whole-body homogenate.
- Changing environment: by comparing environment_1 and environment_2, there is always one condition that is considered different, diet restriction or infection condition.
- Fixed environment: by comparing environment_1 and environment_2, there is always one condition that is considered fixed: control and infection conditions, as well as standard and restricted diets.
- Index (proportion): relative distance plasticity index (RDPI), the difference between the trait values of the same genotype in different environments divided by their sum.
- Mean = Average of indices of one genotype at one changing environment.
- SD = Standard deviation of the indices of one genotype in one changing environment.
- M = Average of the indices of one genotype in diet restriction or infection condition.
- sd = Standard deviation of the indices of one genotype in diet restriction or infection condition.
- Mean_total = Average of the indices of one genotype across all environments.
- sd_total = standard deviation of the indices of one genotype across all environments.
Code/software
There is missing data. Blank cells include n/a.
Access information
Other publicly accessible locations of the data:
- No
Data was derived from the following sources:
- No
Methods
Two isofemale (homogenous) lines of Drosophila melanogaster were selected for use in the present study based on emergence percentage (survivorship) and referred to as A and B. Line A was the population that produced the lowest emergence rate while line B was the population that produced the highest emergence rate of the eight isofemale lines tested. A heterogeneous population (experimental) was created by mixing the eight isofemale lines altogether. To assess the effects of protein-restricted diet and/or infection by Pectobacterium carotovorum on the response of the populations A and B (genotypes) and the heterogeneous population (Exp), first instar Drosophila larvae were allowed to develop under four environmental conditions. These conditions were uninfected+standard diet, uninfected+restricted diet, infected+standard diet, and infected+restricted diet. Parameters such as survivorship, lipid and protein contents, phenol-oxidase activity, and antibacterial rate were assessed following exposure. Moreover, the extent of plasticity among isofemale lines (genotypes) and the heterogeneous population, was calculated using the relative distance plasticity index (RDPI). Survivorship was observed as the number of emerged adults out of ten larvae. The lipid and protein contents, phenol-oxidase activity and antibacterial rate were determined spectrophotometrically in the whole body homogenate of D. melanogaster larvae.