scholarly journals Measuring C. elegans spatial foraging and food intake using bioluminescent bacteria

2019 ◽  
Author(s):  
Siyu Serena Ding ◽  
Karen S. Sarkisyan ◽  
Andre E. X. Brown
Keyword(s):  
Food Intake ◽  
Foraging Behaviour ◽  
Light Emission ◽  
Fold Increase ◽  
Food Patch ◽  
Background Signal ◽  
Bioluminescent Bacteria ◽  
C Elegans ◽  
Tightly Coupled ◽  
Lower Background

ABSTRACTFor most animals, feeding includes two behaviours: foraging to find a food patch and food intake once a patch is found. The nematode Caenorhabditis elegans is a useful model for studying the genetics of both behaviours. However, most methods of measuring feeding in worms quantify either foraging behaviour or food intake but not both. Imaging the depletion of fluorescently labelled bacteria provides information on both the distribution and amount of consumption, but even after patch exhaustion a prominent background signal remains, which complicates quantification. Here, we used a bioluminescent Escherichia coli strain to quantify C. elegans feeding. With light emission tightly coupled to active metabolism, only living bacteria are capable of bioluminescence so the signal is lost upon ingestion. We quantified the loss of bioluminescence using N2 reference worms and eat-2 mutants, and found a nearly 100-fold increase in signal-to-background ratio and lower background compared to loss of fluorescence. We also quantified feeding using aggregating npr-1 mutant worms. We found that groups of npr-1 mutants first clear bacteria from each other before foraging collectively for more food; similarly, during high density swarming, only worms at the migrating front are in contact with bacteria. These results demonstrate the usefulness of bioluminescent bacteria for quantifying feeding and suggest a hygiene hypothesis for the function of C. elegans aggregation and swarming.

scholarly journals Measuring Caenorhabditis elegans Spatial Foraging and Food Intake Using Bioluminescent Bacteria

Genetics ◽  
2020 ◽  
Vol 214 (3) ◽  
pp. 577-587 ◽  
Author(s):  
Siyu Serena Ding ◽  
Maksym Romenskyy ◽  
Karen S. Sarkisyan ◽  
Andre E. X. Brown
Keyword(s):  
Caenorhabditis Elegans ◽  
Food Intake ◽  
Light Emission ◽  
Large Population ◽  
Fold Increase ◽  
Bioluminescent Bacteria ◽  
C Elegans ◽  
Link Type ◽  
Tightly Coupled ◽  
Lower Background

For most animals, feeding includes two behaviors: foraging to find a food patch and food intake once a patch is found. The nematode Caenorhabditis elegans is a useful model for studying the genetics of both behaviors. However, most methods of measuring feeding in worms quantify either foraging behavior or food intake, but not both. Imaging the depletion of fluorescently labeled bacteria provides information on both the distribution and amount of consumption, but even after patch exhaustion a prominent background signal remains, which complicates quantification. Here, we used a bioluminescent Escherichia coli strain to quantify C. elegans feeding. With light emission tightly coupled to active metabolism, only living bacteria are capable of bioluminescence, so the signal is lost upon ingestion. We quantified the loss of bioluminescence using N2 reference worms and eat-2 mutants, and found a nearly 100-fold increase in signal-to-background ratio and lower background compared to loss of fluorescence. We also quantified feeding using aggregating npr-1 mutant worms. We found that groups of npr-1 mutants first clear bacteria from within the cluster before foraging collectively for more food; similarly, during large population swarming, only worms at the migrating front are in contact with bacteria. These results demonstrate the usefulness of bioluminescent bacteria for quantifying feeding and generating insights into the spatial pattern of food consumption.

scholarly journals Inversion of pheromone preference optimizes foraging in C. elegans

2020 ◽  
Author(s):  
M. Dal Bello ◽  
A. Pérez-Escudero ◽  
F. C. Schroeder ◽  
J. Gore
Keyword(s):  
Caenorhabditis Elegans ◽  
Simple Model ◽  
Food Intake ◽  
Behavioral Responses ◽  
Food Sources ◽  
Food Patch ◽  
C Elegans ◽  
Foraging Decisions ◽  
Adaptive Solution ◽  
Food Depletion

SummaryForaging animals have to locate food sources that are usually patchily distributed and subject to competition. Deciding when to leave a food patch is challenging and requires the animal to integrate information about food availability with cues signaling the presence of other individuals (e.g. pheromones). To study how social information transmitted via pheromones can aid foraging decisions, we investigated the behavioral responses of the model nematode Caenorhabditis elegans to food depletion and pheromone accumulation in food patches. We experimentally show that animals consuming a food patch leave it at different times and that the leaving time affects the animal preference for its pheromones. In particular, worms leaving early are attracted to their pheromones, while worms leaving later are repelled by them. We further demonstrate that the inversion from attraction to repulsion depends on associative learning and, by implementing a simple model, we highlight that it is an adaptive solution to optimize food intake during foraging.

scholarly journals Inversion of pheromone preference optimizes foraging in C. elegans

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Martina Dal Bello ◽  
Alfonso Pérez-Escudero ◽  
Frank C Schroeder ◽  
Jeff Gore
Keyword(s):  
Simple Model ◽  
Food Intake ◽  
Behavioral Responses ◽  
Food Sources ◽  
Food Patch ◽  
C Elegans ◽  
Model Animal ◽  
Foraging Decisions ◽  
Adaptive Solution ◽  
Food Depletion

Foraging animals have to locate food sources that are usually patchily distributed and subject to competition. Deciding when to leave a food patch is challenging and requires the animal to integrate information about food availability with cues signaling the presence of other individuals (e.g., pheromones). To study how social information transmitted via pheromones can aid foraging decisions, we investigated the behavioral responses of the model animal Caenorhabditis elegans to food depletion and pheromone accumulation in food patches. We experimentally show that animals consuming a food patch leave it at different times and that the leaving time affects the animal preference for its pheromones. In particular, worms leaving early are attracted to their pheromones, while worms leaving later are repelled by them. We further demonstrate that the inversion from attraction to repulsion depends on associative learning and, by implementing a simple model, we highlight that it is an adaptive solution to optimize food intake during foraging.

Gene-environment interactions at the foraging locus of Drosophila

2021 ◽  
Author(s):  
Simon Benmaamar ◽  
◽  
Björn Brembs
Keyword(s):  
Foraging Behaviour ◽  
Environmental Variability ◽  
Larval Density ◽  
Fruit Fly ◽  
Food Patch ◽  
Factors Affecting ◽  
Larval Behaviour ◽  
Gene Environment ◽  
Behavioural Patterns ◽  
Path Lengths

Environmental variability during the development of an organism has known impacts on the expression of certain behavioural patterns. We used the fruit fly Drosophila melanogaster to investigate how different environmental conditions interact with the allelic variants of rover (forR) and sitter (fors) at the foraging locus to affect food-related behaviour of larvae. We discovered that larval density and nutrient availability were key environmental factors affecting the larval behaviour during early development. High larval density decreased the tendency of rovers to leave a food patch and reduced their travelled path lengths, such that rovers and sitters showed no more significant differences regarding their behaviour. Similar results were obtained when starving the larvae. Furthermore, cutting the availability only of specific nutrients such as sugar, fat or protein during development all affected larval foraging behaviour and locomotion.

Measuring C. elegans food intake in liquid culture

2015 ◽  
Author(s):  
Rafael Gomez-Amaro ◽  
Rafael Gomez-Amaro ◽  
Michael Petrascheck
Keyword(s):  
Food Intake ◽  
Liquid Culture ◽  
C Elegans

The effect of high multivitamin diet during pregnancy on food intake and glucose metabolism in Wistar rat offspring fed low-vitamin diets post weaning

2011 ◽  
Vol 2 (5) ◽  
pp. 302-310 ◽  
Author(s):  
I. M. Y. Szeto ◽  
P. S. P. Huot ◽  
S. A. Reza-López ◽  
A. Jahan-mihan ◽  
G. H. Anderson
Keyword(s):  
Metabolic Syndrome ◽  
Food Intake ◽  
Insulin Response ◽  
Fold Increase ◽  
Wistar Rat ◽  
Oral Glucose ◽  
Glucose Response ◽  
Rat Offspring ◽  
Vitamin Content ◽  
The Metabolic Syndrome

Rat offspring born to dams fed a high multivitamin diet (HV) are shown to have increased risks of obesity and metabolic syndrome. We hypothesized that a low-vitamin postweaning diet would enhance these characteristics in offspring born to HV dams. During pregnancy, Wistar rats were fed the AIN-93G diet with or without a 10-fold increase in vitamin content. In Experiment 1, at weaning, males were fed the recommended diet (RV) or a diet with 1/3 the vitamin content (1/3 RV) for 12 weeks. In Experiment 2, males and females were fed the RV diet or 1/6 RV diet for 35 weeks. Body weight was measured on a weekly basis, food intake on a daily basis, and for 1 h after an overnight fast following glucose gavage at 6, 12 and 24 weeks. Blood glucose and insulin responses to an oral glucose load were measured at 30 weeks. Males from HV dams, compared with those from RV dams, gained more weight in Experiment 1 (+7%,P< 0.05) and Experiment 2 (+11%,P< 0.0001), along with higher glucose response (+33%,P< 0.05). The 1/6 RV pup diet led to lower weight gain in males (−16%,P< 0.0001) and females (−13%,P< 0.0005), and lower food intake in males (−9%,P< 0.01) independent of the gestational diet. Females on the 1/6 RV diet and from HV dams had higher 1 h food intake (+36%,P< 0.05) and lower insulin response (−25%,P< 0.05) compared with those from RV dams. Exposure of the offspring to low-vitamin diets did not amplify the expression of the metabolic syndrome observed in those born to dams fed an HV diet.

scholarly journals Circadian Rhythm of Circulating Levels of the Endocannabinoid 2-Arachidonoylglycerol

2015 ◽  
Vol 100 (1) ◽  
pp. 220-226 ◽  
Author(s):  
E. C. Hanlon ◽  
E. Tasali ◽  
R. Leproult ◽  
K. L. Stuhr ◽  
E. Doncheck ◽  
...  
Keyword(s):  
Food Intake ◽  
Circadian Variation ◽  
Fold Increase ◽  
Structural Analog ◽  
Serum Concentrations ◽  
Endogenous Ligand ◽  
The Third ◽  
Lower Amplitude ◽  
Circulating Levels ◽  
Peripheral Metabolism

Abstract Context: The endocannabinoid (eCB) system is involved in the regulation of food intake and of peripheral metabolism. Although the cross talk between energy metabolism and the circadian system is well documented, little is known about a potential circadian modulation of human eCB activity. Objective: The objective of the study was to define the 24-hour profile of circulating levels of the most abundant endogenous ligand of the CB1 receptor, 2-arachidonoylglycerol (2-AG), in healthy young nonobese adults studied under controlled bedtime, dietary, and activity conditions. Methods: Fourteen subjects participated in this 4-day laboratory study with fixed light-dark cycles, standardized meals, and bedtimes. Sleep was recorded each night. On the third day, blood sampling at 15- to 30-minute intervals began at 9:30 pm and continued for 24 hours. Cortisol, leptin, and ghrelin were assayed on all samples, whereas the levels of 2-AG and its structural analog, 2-oleoylglycerol (2-OG), were measured at 60-minute intervals. Results: All participants exhibited a large circadian variation of 2-AG serum concentrations with a nadir around midsleep, coincident with the middle of the overnight fast. Levels of 2-AG increased continually across the morning, peaking in the early to midafternoon. Peak values represented, on average, a nearly 3-fold increase above nocturnal nadir levels. Concentrations of 2-OG followed a similar pattern, although with a shorter morning increase and lower amplitude. Conclusions: The findings demonstrate that activity of the eCB system is profoundly modulated by circadian rhythmicity and suggest that its impact on the regulation of food intake is suppressed during sleep and is maximal during early to midafternoon.

scholarly journals Triiodothyronine Stimulates Food Intake via the Hypothalamic Ventromedial Nucleus Independent of Changes in Energy Expenditure

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 5252-5258 ◽  
Author(s):  
Wing May Kong ◽  
Niamh M. Martin ◽  
Kirsty L. Smith ◽  
James V. Gardiner ◽  
Ian P. Connoley ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Fold Increase ◽  
Peripheral Circulation ◽  
Negative Energy ◽  
Early Gene ◽  
Ventromedial Nucleus ◽  
Mrna Levels ◽  
Iodothyronine Deiodinase ◽  
Nocturnal Feeding

Abstract Increased food intake is characteristic of hyperthyroidism, although this is presumed to compensate for a state of negative energy balance. However, here we show that the thyroid hormone T3 directly stimulates feeding at the level of the hypothalamus. Peripheral administration of T3 doubled food intake in ad libitum-fed rats over 2 h and induced expression of the immediate early gene, early growth response-1, in the hypothalamic ventromedial nucleus (VMN), whereas maintaining plasma-free T3 levels within the normal range. T3-induced feeding occurred without altering energy expenditure or locomotion. Injection of T3 directly into the VMN produced a 4-fold increase in food intake in the first hour. The majority of T3 in the brain is reported to be produced by tissue-specific conversion of T4 to T3 by the enzyme type 2 iodothyronine deiodinase (D2). Hypothalamic D2 mRNA expression showed a diurnal variation, with a peak in the nocturnal feeding phase. Hypothalamic D2 mRNA levels also increased after a 12- and 24-h fast, suggesting that local production of T3 may play a role in this T3 feeding circuit. Thus, we propose a novel hypothalamic feeding circuit in which T3, from the peripheral circulation or produced by local conversion, stimulates food intake via the VMN.

scholarly journals Cholecalciferol supplementation alters gut function and improves digestibility in an underground inhabitant, the naked mole rat (Heterocephulus gluber), when fed on a carrot diet

1993 ◽  
Vol 69 (1) ◽  
pp. 233-241 ◽  
Author(s):  
Shlomo Yahav ◽  
Rochelle Buffenstein
Keyword(s):  
Food Intake ◽  
Short Chain Fatty Acid ◽  
Fold Increase ◽  
Gas Production ◽  
Heterocephalus Glaber ◽  
Oral Supplementation ◽  
Mole Rat ◽  
Gut Function ◽  
Cholecalciferol Supplementation ◽  
Caecal Fermentation

Naked mole rats (Heterocephalus glaber) lead a strictly subterranean existence and appear to be naturally deficient in cholecalciferol (D3). Oral supplementation with D3(Ds) led to a 1.8-fold increase in food intake and the associated enlargement (1.4-fold) of the caecum. The effect of Ds, and the concomitant increase in food intake, on caecal fermentation efficiency when animals were fed on a carrotbased diet was determined by measuring the rate of both gas production and short-chain fatty acid (SCFA) production. Microbial-controlled fermentation processes in the caecum were enhanced with Dswhen compared with animals not receiving a D3supplement (Dn). Both the rates of gas production (Dn10.76 (SE 0.77), Ds15.20 (SE 1.77) ml/g dry matter (DM) per h) and SCFA production (Dn463.0 (SE 33.7), Ds684.3 (SE 74.8)μmol/g DM per h) increased more than 1.4-fold per g DM caecal substrate. These factors contributed to the higher digestibility of the food in Dsanimals. The larger quantity of energy available to D3-replete naked mole rats was not used in anabolic processes, for these animals maintained mass. These findings suggest that metabolic rate in D3-replete animals was elevated. Thus, despite improved gut function, D3-replete animals may be disadvantaged by their higher energy and food requirements in their natural milieu.

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