Chemically induced oxidative stress affects ASH neuronal function and behavior in C. elegans

Gourgou, Eleni; Chronis, Nikos

doi:10.1038/srep38147

Cited by 16 publications

(25 citation statements)

References 67 publications

(90 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2f) and non-ROS-generating aversive stimuli rely on distinct genetic pathways, although both include lite-1. These results demonstrate that color-dependent potentiation of lawn avoidance is not specific to ROS-generating toxins, does not involve previously demonstrated ROS-induced alterations on ASH-mediated sensory responses 28,29 , and generalizes to other aversive stimuli that do not operate through generation of…”

supporting

confidence: 57%

C. elegansdiscriminate colors without eyes or opsins

Ghosh

Nitabach

2016

Preprint

View full text Add to dashboard Cite

Here we establish that, contrary to expectations, Caenorhabditis elegans nematode worms possess a color discrimination system despite lacking any opsin or other known visible light photoreceptor genes. We found that white light guides C. elegans foraging decisions away from harmful bacteria that secrete a blue pigment toxin. Absorption of amber light by this blue pigment toxin alters the color of light sensed by the worm, and thereby triggers an increase in avoidance. By combining narrow-band blue and amber light sources, we demonstrated that detection of the specific blue:amber ratio by the worm guides its foraging decision. These behavioral and psychophysical studies thus establish the existence of a color detection system that is distinct from those of other animals.3 Main text:C. elegans live in decomposing organic matter where they feed on microorganisms 1-3 , some of which secrete colorful pigments. While C. elegans lack any specialized photoreceptor cells or opsin genes, they possess an illuminance sensing system that mediates rapid escape responses to short-wavelength light 4-6 . However, it is unknown whether C. elegans use light information, potentially including color, to inform complex decisions like foraging in environments containing colorful food sources. To address this question, we first tested whether white light alters foraging decisions on P. aeruginosa bacterial lawns containing the blue pigment toxin pyocyanin, one of a number of small molecule phenazine toxins secreted by P. aeruginosa 7-10 . We employed an 8 kilolux LED array white light source to mimic naturalistic lighting levels (Fig. 1a, Supplementary Fig. 1a). Previous studies have shown that foraging decisions to remain on or leave a bacterial lawn are guided by a variety of factors 11,12 . Worms remain on bacterial lawns that are easy to eat and support growth, while leaving lawns that are of poor nutritive quality, repulsive, or pathogenic [11][12][13][14][15][16] . Worms are initially attracted to P. aeruginosa lawns, but over a time course of hours, as the P. aeruginosa continues to divide and secrete toxins, they respond to its increasingly aversive qualities and begin to leave 14,15,[17][18][19][20] .Whether light plays a role in guiding avoidance of P. aeruginosa has never been tested. Here we employed a standard lawn avoidance assay, placing worms on a P. aeruginosa lawn in the center of an agar plate, and quantified the time course of avoidance as the fraction of worms found off the lawn (Fig. 1a). Consistent with prior studies, worms gradually avoid P. aeruginosa strain PA14 over a span of many hours 14,15,[17][18][19][20] (Fig. 1a). Surprisingly, however, this avoidance is dramatically potentiated by white light (Fig. 1b). White light does not potentiate avoidance of

show abstract

supporting

confidence: 57%

C. elegansdiscriminate colors without eyes or opsins

Ghosh

Nitabach

2016

Preprint

View full text Add to dashboard Cite

show abstract

“…The Ca 2+ concentration obtained using the mathematical model can be related to signals measured in experiments (17,21). Experimental signals obtained using TN-XL FRET (fluorescence resonance energy transfer) measurements (55) are the result of Ca 2+ interaction with an indicator genetically encoded in the C. elegans ASH neuron.…”

Section: Ca 2+ Concentration To Fret Signal Conversionmentioning

confidence: 99%

“…The use of Ca 2+ transients to indirectly assess a neuron's activation is a wellestablished approach (1-3) despite its limitations, and despite the extra care needed to draw conclusions about the neuron's concurrent activation (4)(5)(6)(7). A the same time, C. elegans has been proved ideal for applying imaging techniques to monitor Ca 2+ transients generated upon stimulation of a variety of neurons (2,(8)(9)(10)(11)(12)(13), in freely moving (9,14) as well as in immobilized worms, by using traditional approaches (3,4,15,16) or advanced methods (2,(17)(18)(19)(20)(21). The ASH polymodal neuron is the subject of numerous such studies (17,18,21,22), because of its key importance as a nociceptor for the worms' survival and also because it is the starting player for a plethora of downstream neuronal events.…”

Section: Introductionmentioning

confidence: 99%

“…A the same time, C. elegans has been proved ideal for applying imaging techniques to monitor Ca 2+ transients generated upon stimulation of a variety of neurons (2,(8)(9)(10)(11)(12)(13), in freely moving (9,14) as well as in immobilized worms, by using traditional approaches (3,4,15,16) or advanced methods (2,(17)(18)(19)(20)(21). The ASH polymodal neuron is the subject of numerous such studies (17,18,21,22), because of its key importance as a nociceptor for the worms' survival and also because it is the starting player for a plethora of downstream neuronal events. The use of microfluidic chips for the immobilization of worms and the delivery of stimuli has revealed not only the first peak in the Ca 2+ transients of the ASH neuron occurring upon stimulation (the "on" response), but also a second peak occurring upon withdrawal of the stimulus (the "off" response) (18,23,24).…”

Section: Introductionmentioning

confidence: 99%

“…In parallel, Ca 2+ transients (3) have been studied in ASH neurons in the context of different biological conditions, including aging (17,22), oxidative stress (11,21), food availability (29) and oxygen concentration (30). Extended efforts have been made to decipher the molecular players involved (3,4,23,25,31).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A mathematical and computational model of the calcium dynamics inCaenorhabditis elegansASH sensory neuro

Mirzakhalili

Epureanu

Gourgou

2017

Preprint

Self Cite

View full text Add to dashboard Cite

We propose a mathematical and computational model that captures the stimulusgenerated Ca 2+ transients in the C. elegans ASH sensory neuron. The model is built based on biophysical events and molecular cascades known to unfold as part of neurons' Ca 2+ homeostasis mechanism, as well as on Ca 2+ signaling events. The state of ion channels is described by their probability of being activated or inactivated, and the remaining molecular states are based on biochemically defined kinetic equations with phenomenological adjustments. We estimate the parameters of the model using experimental data of hyperosmotic stimulus-evoked Ca 2+ transients detected with a FRET sensor in young and aged worms, unstressed and exposed to oxidative stress. We use a hybrid optimization method composed of a multi-objective genetic algorithm and nonlinear least-squares to estimate the model parameters. We first obtain the model parameters for young unstressed worms. Next, we use these values of the parameters as a starting point to identify the model parameters for stressed and aged worms. We show that the model, in combination with experimental data, corroborates literature results. In addition, we demonstrate that our model can be used to predict ASH response to complex combinations of stimulation pulses. The proposed model includes for the first time the ASH Ca 2+ dynamics observed during both "on" and "off"responses. This mathematical and computational effort is the first to propose a dynamic model of the Ca 2+ transients' mechanism in C. elegans neurons, based on biochemical pathways of the cell's Ca 2+ homeostasis machinery.Key words: C. elegans, calcium dynamics, ASH neuron, aging, oxidative stress Significance StatementC. elegans is widely used as a model system for monitoring neuronal Ca 2+ transients.The ASH neuron is the subject of several such studies, primarily due to its key importance as a polymodal nociceptor. However, despite its pivotal role in C. elegans biology, and the special characteristics of its stimulus-evoked Ca2 + transients (e.g., the peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission.The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/201962 doi: bioRxiv preprint first posted online Oct. 12, 2017; "off" response), no mathematical or computational model has been developed to include special features of ASH Ca 2+ dynamics, i.e. the "off" response. The model includes for the first time the ASH Ca 2+ dynamics observed during both "on" and "off" responses, and is the first to propose a dynamical model of the C. elegans Ca 2+ transients' mechanism based on biochemical pathways of the cell's Ca 2+ homeostasis machinery.

show abstract

Toxicity Induction in Neurons and Muscle in Nematodes Exposed to Environmental Toxicants or Stresses

Wang

2019

Target Organ Toxicology in Caenorhabditis Elegans

View full text Add to dashboard Cite

Chemically induced oxidative stress affects ASH neuronal function and behavior in C. elegans

Cited by 16 publications

References 67 publications

C. elegansdiscriminate colors without eyes or opsins

C. elegansdiscriminate colors without eyes or opsins

A mathematical and computational model of the calcium dynamics inCaenorhabditis elegansASH sensory neuro

Toxicity Induction in Neurons and Muscle in Nematodes Exposed to Environmental Toxicants or Stresses

Contact Info

Product

Resources

About