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Measuring Food Intake and Nutrient Absorption in Caenorhabditis elegans.

Gomez-Amaro RL, Valentine ER, Carretero M, LeBoeuf SE, Rangaraju S, Broaddus CD, Solis GM, Williamson JR, Petrascheck M - Genetics (2015)

Bottom Line: Caenorhabditis elegans has emerged as a powerful model to study the genetics of feeding, food-related behaviors, and metabolism.We show that serotonin-increased feeding leads to increased protein synthesis in a SER-7-dependent manner, including proteins known to promote aging.Protein content in the food has recently emerged as critical factor in determining how food composition affects aging and health.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037 Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037 Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037.

No MeSH data available.


Measurement of bacterial clearance with C. elegans. (A) A 96-well liquid culture format. (B) Morphology of day 1 (D1) adult N2 worms grown on solid NGM plates (top) or in liquid culture (bottom). (C) The bacterial clearance assay. Schematic of worms placed into wells with an optical bottom to monitor bacterial concentrations by measuring the optical density (absorbance) at 600 nm (OD600). Side and top view. (D) Bacterial clearance is only observed in the presence of worms. Tukey-style box plots. OD600 depicting four time points, comparing wild-type N2 vs. no worms, nwells = 12 biological replicates (e.g., wells). Data represent five independent experiments. ***P < 0.001, two-way ANOVA with Bonferroni post hoc test. (E) Bacterial clearance is observed for bacteria killed by irradiation. Data represent three independent experiments. Wells with N2 (nwells = 6), wells with no worms (nwells = 3). (F–H) OD600 measurements are not influenced by the presence of eggs and depend only on the presence of worms eating bacteria. OD600 on D1 and D4 for wells containing (F) S-complete only, (G) N2 and eggs in S-complete with OP50 removed, or (H) N2 plus bacteria in S-complete. Data represent three independent experiments. (I) Bacterial clearance correlates with the number of worms per well (X0). Values depict bacterial clearance over 72 hr (D1:D4). Data depict 95% confidence interval (dashed lines), goodness of fit statistic (R2), and Spearman’s correlation ρ (P < 0.0001). Data represent three independent experiments (nwells = 84). (J) Data from I normalized to worms per well. (K) Age-related changes in food intake. Food intake expressed relative to bacterial clearance within the L4:D1 interval. Data represent three independent experiments (nwells = 36).
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fig1: Measurement of bacterial clearance with C. elegans. (A) A 96-well liquid culture format. (B) Morphology of day 1 (D1) adult N2 worms grown on solid NGM plates (top) or in liquid culture (bottom). (C) The bacterial clearance assay. Schematic of worms placed into wells with an optical bottom to monitor bacterial concentrations by measuring the optical density (absorbance) at 600 nm (OD600). Side and top view. (D) Bacterial clearance is only observed in the presence of worms. Tukey-style box plots. OD600 depicting four time points, comparing wild-type N2 vs. no worms, nwells = 12 biological replicates (e.g., wells). Data represent five independent experiments. ***P < 0.001, two-way ANOVA with Bonferroni post hoc test. (E) Bacterial clearance is observed for bacteria killed by irradiation. Data represent three independent experiments. Wells with N2 (nwells = 6), wells with no worms (nwells = 3). (F–H) OD600 measurements are not influenced by the presence of eggs and depend only on the presence of worms eating bacteria. OD600 on D1 and D4 for wells containing (F) S-complete only, (G) N2 and eggs in S-complete with OP50 removed, or (H) N2 plus bacteria in S-complete. Data represent three independent experiments. (I) Bacterial clearance correlates with the number of worms per well (X0). Values depict bacterial clearance over 72 hr (D1:D4). Data depict 95% confidence interval (dashed lines), goodness of fit statistic (R2), and Spearman’s correlation ρ (P < 0.0001). Data represent three independent experiments (nwells = 84). (J) Data from I normalized to worms per well. (K) Age-related changes in food intake. Food intake expressed relative to bacterial clearance within the L4:D1 interval. Data represent three independent experiments (nwells = 36).

Mentions: C. elegans can be grown in 96-well microtiter plates in liquid medium by seeding 4–12 developmentally synchronized L1 larvae into individual wells with E. coli as a food source. Young adults raised in this form of liquid culture are morphologically very similar to age-matched adults raised on NGM (Figure 1, A and B; Supporting Information, Figure S1). They do not show the elongated and starved appearance seen in other types of liquid culture. Incidentally, we observed that the wells of microtiter plates containing worms plus bacteria become optically clearer over the course of several days. We reasoned that, by measuring the change in bacterial concentration over time in a well, we could quantify the amount of bacteria eaten by the worms.


Measuring Food Intake and Nutrient Absorption in Caenorhabditis elegans.

Gomez-Amaro RL, Valentine ER, Carretero M, LeBoeuf SE, Rangaraju S, Broaddus CD, Solis GM, Williamson JR, Petrascheck M - Genetics (2015)

Measurement of bacterial clearance with C. elegans. (A) A 96-well liquid culture format. (B) Morphology of day 1 (D1) adult N2 worms grown on solid NGM plates (top) or in liquid culture (bottom). (C) The bacterial clearance assay. Schematic of worms placed into wells with an optical bottom to monitor bacterial concentrations by measuring the optical density (absorbance) at 600 nm (OD600). Side and top view. (D) Bacterial clearance is only observed in the presence of worms. Tukey-style box plots. OD600 depicting four time points, comparing wild-type N2 vs. no worms, nwells = 12 biological replicates (e.g., wells). Data represent five independent experiments. ***P < 0.001, two-way ANOVA with Bonferroni post hoc test. (E) Bacterial clearance is observed for bacteria killed by irradiation. Data represent three independent experiments. Wells with N2 (nwells = 6), wells with no worms (nwells = 3). (F–H) OD600 measurements are not influenced by the presence of eggs and depend only on the presence of worms eating bacteria. OD600 on D1 and D4 for wells containing (F) S-complete only, (G) N2 and eggs in S-complete with OP50 removed, or (H) N2 plus bacteria in S-complete. Data represent three independent experiments. (I) Bacterial clearance correlates with the number of worms per well (X0). Values depict bacterial clearance over 72 hr (D1:D4). Data depict 95% confidence interval (dashed lines), goodness of fit statistic (R2), and Spearman’s correlation ρ (P < 0.0001). Data represent three independent experiments (nwells = 84). (J) Data from I normalized to worms per well. (K) Age-related changes in food intake. Food intake expressed relative to bacterial clearance within the L4:D1 interval. Data represent three independent experiments (nwells = 36).
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig1: Measurement of bacterial clearance with C. elegans. (A) A 96-well liquid culture format. (B) Morphology of day 1 (D1) adult N2 worms grown on solid NGM plates (top) or in liquid culture (bottom). (C) The bacterial clearance assay. Schematic of worms placed into wells with an optical bottom to monitor bacterial concentrations by measuring the optical density (absorbance) at 600 nm (OD600). Side and top view. (D) Bacterial clearance is only observed in the presence of worms. Tukey-style box plots. OD600 depicting four time points, comparing wild-type N2 vs. no worms, nwells = 12 biological replicates (e.g., wells). Data represent five independent experiments. ***P < 0.001, two-way ANOVA with Bonferroni post hoc test. (E) Bacterial clearance is observed for bacteria killed by irradiation. Data represent three independent experiments. Wells with N2 (nwells = 6), wells with no worms (nwells = 3). (F–H) OD600 measurements are not influenced by the presence of eggs and depend only on the presence of worms eating bacteria. OD600 on D1 and D4 for wells containing (F) S-complete only, (G) N2 and eggs in S-complete with OP50 removed, or (H) N2 plus bacteria in S-complete. Data represent three independent experiments. (I) Bacterial clearance correlates with the number of worms per well (X0). Values depict bacterial clearance over 72 hr (D1:D4). Data depict 95% confidence interval (dashed lines), goodness of fit statistic (R2), and Spearman’s correlation ρ (P < 0.0001). Data represent three independent experiments (nwells = 84). (J) Data from I normalized to worms per well. (K) Age-related changes in food intake. Food intake expressed relative to bacterial clearance within the L4:D1 interval. Data represent three independent experiments (nwells = 36).
Mentions: C. elegans can be grown in 96-well microtiter plates in liquid medium by seeding 4–12 developmentally synchronized L1 larvae into individual wells with E. coli as a food source. Young adults raised in this form of liquid culture are morphologically very similar to age-matched adults raised on NGM (Figure 1, A and B; Supporting Information, Figure S1). They do not show the elongated and starved appearance seen in other types of liquid culture. Incidentally, we observed that the wells of microtiter plates containing worms plus bacteria become optically clearer over the course of several days. We reasoned that, by measuring the change in bacterial concentration over time in a well, we could quantify the amount of bacteria eaten by the worms.

Bottom Line: Caenorhabditis elegans has emerged as a powerful model to study the genetics of feeding, food-related behaviors, and metabolism.We show that serotonin-increased feeding leads to increased protein synthesis in a SER-7-dependent manner, including proteins known to promote aging.Protein content in the food has recently emerged as critical factor in determining how food composition affects aging and health.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037 Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037 Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037.

No MeSH data available.