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.

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 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.

Risk Assessment of Sulphite Exposure through Foods Among Adolescents of Delhi (India)

2019 ◽  
Vol 15 (7) ◽  
pp. 685-693
Author(s):  
Arushi Jain ◽  
Pulkit Mathur
Keyword(s):  
Risk Assessment ◽  
Food Intake ◽  
Daily Intake ◽  
Food Sources ◽  
Acceptable Daily Intake ◽  
Food Record ◽  
Government Schools ◽  
Adverse Health Effects ◽  
Food Items ◽  
Permissible Levels

Background: Sulphites added as preservatives in food have been associated with adverse health effects in humans. Objective: The present study was designed with an objective of assessing the risk of sulphite exposure through food in adolescents (12-16 years old) of Delhi, India. Methods: A total of 1030 adolescents selected from four private and four government schools of Delhi, were asked to record their food intake using a 24 hour food record, repeated on three days, for assessing exposure to sulphites. The risk was assessed using six different scenarios of exposure. Results: The actual intake for sulphites for average consumers was 0.15 ± 0.13 mg / kg b.w. / day which was 21.4% of acceptable daily intake (ADI). For high consumers (P95), it was 65% of the ADI. However, for 2 respondents, the actual intake exceeded the ADI. The major food contributors to sulphite intake were beverage concentrates (46%), ready to serve beverages (22%) followed by miscellaneous food items (16%), mainly ice creams and snowballs. Estimation of sulphite intake using different exposure scenarios revealed that for certain scenarios where the highest reported sulphite level or maximum permissible levels were considered for calculation, the high consumers exceeded the ADI, though, for average consumers, intake was well below the ADI. Conclusion: Actual intake of sulphite for average consumers was well below the ADI but for high consumers was approaching the ADI. People with sulphite sensitivity need to be aware of hidden food sources of sulphites.

scholarly journals C. elegans discriminates colors to guide foraging

Science ◽  
2021 ◽  
Vol 371 (6533) ◽  
pp. 1059-1063 ◽  
Author(s):  
D. Dipon Ghosh ◽  
Dongyeop Lee ◽  
Xin Jin ◽  
H. Robert Horvitz ◽  
Michael N. Nitabach
Keyword(s):  
Stress Response ◽  
Cellular Stress ◽  
Color Discrimination ◽  
Cellular Stress Response ◽  
Blue Pigment ◽  
Natural Environments ◽  
C Elegans ◽  
Evolutionarily Conserved ◽  
Foraging Decisions ◽  
Light Guides

Color detection is used by animals of diverse phyla to navigate colorful natural environments and is thought to require evolutionarily conserved opsin photoreceptor genes. We report that Caenorhabditis elegans roundworms can discriminate between colors despite the fact that they lack eyes and opsins. Specifically, we found that white light guides C. elegans foraging decisions away from a blue-pigment toxin secreted by harmful bacteria. These foraging decisions are guided by specific blue-to-amber ratios of light. The color specificity of color-dependent foraging varies notably among wild C. elegans strains, which indicates that color discrimination is ecologically important. We identified two evolutionarily conserved cellular stress response genes required for opsin-independent, color-dependent foraging by C. elegans, and we speculate that cellular stress response pathways can mediate spectral discrimination by photosensitive cells and organisms—even by those lacking opsins.

An integrated view of innate immune mechanisms in C. elegans

2021 ◽  
Author(s):  
Benjamin W. Harding ◽  
Jonathan J. Ewbank
Keyword(s):  
Innate Immune ◽  
Innate Immune Responses ◽  
Fully Integrated ◽  
Immune Mechanisms ◽  
C Elegans ◽  
Cellular Processes ◽  
Physiological Processes ◽  
Model Animal ◽  
Molecular Specificity ◽  
Simple Notion

The simple notion ‘infection causes an immune response' is being progressively refined as it becomes clear that immune mechanisms cannot be understood in isolation, but need to be considered in a more global context with other cellular and physiological processes. In part, this reflects the deployment by pathogens of virulence factors that target diverse cellular processes, such as translation or mitochondrial respiration, often with great molecular specificity. It also reflects molecular cross-talk between a broad range of host signalling pathways. Studies with the model animal C. elegans have uncovered a range of examples wherein innate immune responses are intimately connected with different homeostatic mechanisms, and can influence reproduction, ageing and neurodegeneration, as well as various other aspects of its biology. Here we provide a short overview of a number of such connections, highlighting recent discoveries that further the construction of a fully integrated view of innate immunity.

How long does a dive last? Foraging decisions by breath-hold divers in a patchy environment: a test of a simple model

2007 ◽  
Vol 74 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Carol E. Sparling ◽  
Jean-Yves Georges ◽  
Susan L. Gallon ◽  
Mike Fedak ◽  
Dave Thompson
Keyword(s):  
Simple Model ◽  
Breath Hold ◽  
Patchy Environment ◽  
Foraging Decisions

scholarly journals A quiescent state following mild sensory arousal in Caenorhabditis elegans is potentiated by stress

2019 ◽  
Author(s):  
Patrick D. McClanahan ◽  
Jessica M. Dubuque ◽  
Daphne Kontogiorgos-Heintz ◽  
Ben F. Habermeyer ◽  
Joyce H. Xu ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Exposure ◽  
Light Stimulus ◽  
Low Frequency ◽  
Behavioral Responses ◽  
Quiescent State ◽  
Sleep State ◽  
C Elegans ◽  
Epidermal Growth ◽  
Cellular Stressors

AbstractAn animal’s behavioral and physiological response to stressors includes changes to its responses to stimuli. How such changes occur is not well understood. Here we describe a Caenorhabditis elegans quiescent behavior, post-response quiescence (PRQ), which is modulated by the C. elegans response to cellular stressors. Following an aversive mechanical or blue light stimulus, worms respond first by briefly moving, and then become more quiescent for a period lasting tens of seconds. PRQ occurs at low frequency in unstressed animals, but is more frequent in animals that have experienced cellular stress due to ultraviolet light exposure as well as in animals following overexpression of epidermal growth factor (EGF). PRQ requires the function of the carboxypeptidase EGL-21 and the calcium-activated protein for secretion (CAPS) UNC-31, suggesting it has a neuropeptidergic mechanism. Although PRQ requires the sleep-promoting neurons RIS and ALA, it is not accompanied by decreased arousability, and does not appear to be homeostatically regulated, suggesting that it is not a sleep state. PRQ represents a simple, tractable model for studying how neuromodulatory states like stress alter behavioral responses to stimuli.

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

Effects of live weight and condition score on food intake of ewe lambs

2003 ◽  
Vol 2003 ◽  
pp. 8-8
Author(s):  
Bert J. Tolkamp ◽  
Gerry C. Emmans ◽  
Ilias Kyriazakis
Keyword(s):  
Simple Model ◽  
Food Intake ◽  
Food Quality ◽  
Scale Up ◽  
Live Weight ◽  
Ewe Lambs ◽  
Condition Score

Food intake (FI) can be predicted on the basis of variables that describe food quality, the environment and the animal. Live weight (LW), in some form or other, is usually the only variable used to describe the animal. Animal fatness, estimated by condition score (CS), can affect intake at a given LW. A simple model to account for that is FI= a.LW.(1-b.CS) with FI in g/day, LW in kg and CS in units of a scale up to 5. It is evident that food quality will affect parameter a. Here we test the hypothesis that the parameter b in this model is significant but not affected by food quality. To that end, we measured LW, CS and intake of three different foods with ewe lambs that showed a large variation in LW and CS as a result of different nutritional histories.

scholarly journals Acyl-CoA-binding protein (ACBP): a phylogenetically conserved appetite stimulator

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nikolaos Charmpilas ◽  
Christoph Ruckenstuhl ◽  
Valentina Sica ◽  
Sabrina Büttner ◽  
Lukas Habernig ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Anorexia Nervosa ◽  
Caenorhabditis Elegans ◽  
Food Intake ◽  
Binding Protein ◽  
Plasma Concentrations ◽  
Food Sources ◽  
Knowing That ◽  
Pharyngeal Pumping ◽  
Appetite Stimulation

AbstractRecently, we reported that, in mice, hunger causes the autophagy-dependent release of a protein called “acyl-CoA-binding protein” or “diazepam binding inhibitor” (ACBP/DBI) from cells, resulting in an increase in plasma ACBP concentrations. Administration of extra ACBP is orexigenic and obesogenic, while its neutralization is anorexigenic in mice, suggesting that ACBP is a major stimulator of appetite and lipo-anabolism. Accordingly, obese persons have higher circulating ACBP levels than lean individuals, and anorexia nervosa is associated with subnormal ACBP plasma concentrations. Here, we investigated whether ACBP might play a phylogenetically conserved role in appetite stimulation. We found that extracellular ACBP favors sporulation in Saccharomyces cerevisiae, knowing that sporulation is a strategy for yeast to seek new food sources. Moreover, in the nematode Caenorhabditis elegans, ACBP increased the ingestion of bacteria as well as the frequency pharyngeal pumping. These observations indicate that ACBP has a phylogenetically ancient role as a ‘hunger factor’ that favors food intake.

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