Complex Locomotion Behavior Changes Are Induced in Caenorhabditis elegans by the Lack of the Regulatory Leak K+ Channel TWK-7

Larval forms of the free-living nematode Caenorhabditis elegans possess the ability to enter a developmental stage which is thought to be specialized for survival in harsh environmental conditions, i.e. the dauerlarval stage. In this study the responses of dauerlarvae to thermal stress and oxygen deprivation are investigated. Oxygen consumption of dauerlarvae is less sensitive to temperature change that that of adults, with Q10 values of 1.7 and 2.6 respectively. The upper thermal tolerance limit of dauerlarvae is also different from that of adults; dauerlarvae survive approximately three times longer than adults when exposed to 37 °C. In addition to differences in thermal tolerance, dauerlarvae survive longer under anaerobic conditions than adults, 7 days and 2 days respectively. On recovery from anaerobic stress dauerlarvae exhibit behavior changes which are suggestive of emergence from the dauerlarval stage. The responses of dauerlarvae to thermal stress and oxygen deprivation appear to be important aspects of the specialization for survival in this facultative developmental stage.

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The L-type voltage-dependent Ca2+ channel EGL-19 controls body wall muscle function in Caenorhabditis elegans

The Journal of Cell Biology ◽

10.1083/jcb.200203055 ◽

2002 ◽

Vol 159 (2) ◽

pp. 337-348 ◽

Cited By ~ 63

Author(s):

Maëlle Jospin ◽

Vincent Jacquemond ◽

Marie-Christine Mariol ◽

Laurent Ségalat ◽

Bruno Allard

Keyword(s):

Caenorhabditis Elegans ◽

Body Wall ◽

Muscle Cells ◽

Membrane Depolarization ◽

Cellular Level ◽

Body Wall Muscle ◽

K Channel ◽

Channel Blockers ◽

Patch Clamp Technique ◽

Voltage Dependent

Caenorhabditis elegans is a powerful model system widely used to investigate the relationships between genes and complex behaviors like locomotion. However, physiological studies at the cellular level have been restricted by the difficulty to dissect this microscopic animal. Thus, little is known about the properties of body wall muscle cells used for locomotion. Using in situ patch clamp technique, we show that body wall muscle cells generate spontaneous spike potentials and develop graded action potentials in response to injection of positive current of increasing amplitude. In the presence of K+ channel blockers, membrane depolarization elicited Ca2+ currents inhibited by nifedipine and exhibiting Ca2+-dependent inactivation. Our results give evidence that the Ca2+ channel involved belongs to the L-type class and corresponds to EGL-19, a putative Ca2+ channel originally thought to be a member of this class on the basis of genomic data. Using Ca2+ fluorescence imaging on patch-clamped muscle cells, we demonstrate that the Ca2+ transients elicited by membrane depolarization are under the control of Ca2+ entry through L-type Ca2+ channels. In reduction of function egl-19 mutant muscle cells, Ca2+ currents displayed slower activation kinetics and provided a significantly smaller Ca2+ entry, whereas the threshold for Ca2+ transients was shifted toward positive membrane potentials.

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Biosafety Assessment of Acinetobacter Strains Isolated From the Three Gorges Reservoir Region in Nematode Caenorhabditis Elegans

10.21203/rs.3.rs-405417/v1 ◽

2021 ◽

Author(s):

Yunjia Deng ◽

Huihui Du ◽

Mingfeng Tang ◽

Qilong Wang ◽

Qian Huang ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Three Gorges Reservoir ◽

Three Gorges ◽

Exposure Risk ◽

Nematode Caenorhabditis Elegans ◽

The Three Gorges Reservoir ◽

The Three Gorges ◽

Biosafety Assessment ◽

Locomotion Behavior ◽

Reference Strains

Abstract Acinetobacter is an important nosocomial pathogen frequently detected in backwater areas of the Three Gorges Reservoir (TGR) region. We here employed Caenorhabditis elegans to perform biosafety assessment of Acinetobacter strains isolated from the backwater area in the TGR region and reference strains. Among 21 isolates and 5 reference strains of Acinetobacter, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii ATCC 19606T, A. junii NH88-14 and A. lwoffii DSM 2403T resulted in significant decrease in locomotion behavior and reduction in lifespan. In nematodes, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii, A. junii and A. lwoffii also resulted in significant reactive oxygen species (ROS) production. Moreover, exposure to Acinetobacter isolates of AC1, AC15, AC18, and AC21 led to significant increase in expressions of both SOD-3::GFP and some antimicrobial genes (lys-1, spp-12, lys-7, dod-6, spp-1, dod-22, lys-8, and/or F55G11.4) in nematodes. The Acinetobacter isolates of AC1, AC15, AC18, and AC21 had different morphological, biochemical, and phylogenetical properties. Our results suggested that it exists the exposure risk of some Acinetobacter strains isolated from the TGR region for environmental organisms and human health, and Caenorhabditis elegans can be used to assess the biosafety of Acinetobacter isolates from the environment.

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Optogenetic analysis of GABAB receptor signaling in Caenorhabditis elegans motor neurons

Journal of Neurophysiology ◽

10.1152/jn.00578.2010 ◽

2011 ◽

Vol 106 (2) ◽

pp. 817-827 ◽

Cited By ~ 20

Author(s):

Christian Schultheis ◽

Martin Brauner ◽

Jana F. Liewald ◽

Alexander Gottschalk

Keyword(s):

Caenorhabditis Elegans ◽

Motor Neurons ◽

Gabab Receptor ◽

Feedback Inhibition ◽

Cholinergic Neurons ◽

Gaba Release ◽

The Body ◽

Linear Feedback ◽

Locomotion Behavior ◽

Contraction And Relaxation

In the nervous system, a perfect balance of excitation and inhibition is required, for example, to enable coordinated locomotion. In Caenorhabditis elegans, cholinergic and GABAergic motor neurons (MNs) effect waves of contralateral muscle contraction and relaxation. Cholinergic MNs innervate muscle as well as GABAergic MNs, projecting to the opposite side of the body, at dyadic synapses. Only a few connections exist from GABAergic to cholinergic MNs, emphasizing that GABA signaling is mainly directed toward muscle. Yet, a GABAB receptor comprising GBB-1 and GBB-2 subunits, expressed in cholinergic MNs, was shown to affect locomotion, likely by feedback inhibition of cholinergic MNs in response to spillover GABA. In the present study, we examined whether the GBB-1/2 receptor could also affect short-term plasticity in cholinergic MNs with the use of channelrhodopsin-2-mediated photostimulation of GABAergic and cholinergic neurons. The GBB-1/2 receptor contributes to acute body relaxation, evoked by photoactivation of GABAergic MNs, and to effects of GABA on locomotion behavior. Loss of the plasma membrane GABA transporter SNF-11, as well as acute photoevoked GABA release, affected cholinergic MN function in opposite directions. Prolonged stimulation of GABA MNs had subtle effects on cholinergic MNs, depending on stimulus duration and gbb-2. Thus GBB-1/2 receptors serve mainly for linear feedback inhibition of cholinergic MNs but also evoke minor plastic changes.

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Toxicity and multigenerational effects of bisphenol S exposure to Caenorhabditis elegans on developmental, biochemical, reproductive and oxidative stress

Toxicology Research ◽

10.1039/c9tx00055k ◽

2019 ◽

Vol 8 (5) ◽

pp. 630-640 ◽

Cited By ~ 9

Author(s):

Xiang Xiao ◽

Xiaowei Zhang ◽

Caiqin Zhang ◽

Jie Li ◽

Yansheng Zhao ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Significant Inhibition ◽

The Body ◽

Antioxidant Systems ◽

Bisphenol S ◽

Clinical Model ◽

C Elegans ◽

Locomotion Behavior ◽

Limited Application ◽

Multigenerational Effects

Abstract Bisphenol A (BPA) is a typical endocrine disruptor. Bisphenol S (BPS) has been widely used as a substitute for various plastic materials due to the limited application of BPA. However, it does not mean that BPS is a safe substitute due to the lack of effective evaluation of BPS. In this study, the clinical model of Caenorhabditis elegans (C. elegans) was used to study the effects of BPS on the locomotion behavior, growth, reproduction, lifespan and antioxidant system. Our study found that C. elegans exposed to 0.01 μM BPS could have significantly inhibited locomotion behavior and growth, as well as damaged reproductive and antioxidant systems and lifespan. It is interesting to note that in multi-generational exposure studies, we found that BPS exhibits complex genotoxicity. With the transmission to the offspring, BPS showed more significant inhibition of the head thrashes of the nematode, while the effect on the body bends and body length was gradually weakened. The effect of BPS on the brood size shows different rules according to different concentrations and offsprings. Therefore, the safety of BPS still needs further evaluation, especially the multi-generational genotoxicity.

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Toxicity comparison between pristine and sulfonate modified nanopolystyrene particles in affecting locomotion behavior, sensory perception, and neuronal development in Caenorhabditis elegans

The Science of The Total Environment ◽

10.1016/j.scitotenv.2019.134817 ◽

2020 ◽

Vol 703 ◽

pp. 134817 ◽

Cited By ~ 31

Author(s):

Man Qu ◽

Dayong Wang

Keyword(s):

Caenorhabditis Elegans ◽

Neuronal Development ◽

Sensory Perception ◽

Locomotion Behavior

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microRNAs involved in the control of toxicity on locomotion behavior induced by simulated microgravity stress in Caenorhabditis elegans

Scientific Reports ◽

10.1038/s41598-020-74582-z ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Lingmei Sun ◽

Wenjie Li ◽

Dan Li ◽

Dayong Wang

Keyword(s):

Oxidative Stress ◽

Functional Analysis ◽

Caenorhabditis Elegans ◽

Molecular Basis ◽

Simulated Microgravity ◽

Signaling Cascade ◽

Protective Response ◽

Epigenetic Control ◽

Candidate Mirnas ◽

Locomotion Behavior

Abstract microRNAs (miRNAs) post-transcriptionally regulate the expression of targeted genes. We here systematically identify miRNAs in response to simulated microgravity based on both expressions and functional analysis in Caenorhabditis elegans. After simulated microgravity treatment, we observed that 19 miRNAs (16 down-regulated and 3 up-regulated) were dysregulated. Among these dysregulated miRNAs, let-7, mir-54, mir-67, mir-85, mir-252, mir-354, mir-789, mir-2208, and mir-5592 were required for the toxicity induction of simulated microgravity in suppressing locomotion behavior. In nematodes, alteration in expressions of let-7, mir-67, mir-85, mir-252, mir-354, mir-789, mir-2208, and mir-5592 mediated a protective response to simulated microgravity, whereas alteration in mir-54 expression mediated the toxicity induction of simulated microgravity. Moreover, among these candidate miRNAs, let-7 regulated the toxicity of simulated microgravity by targeting and suppressing SKN-1/Nrf protein. In the intestine, a signaling cascade of SKN-1/Nrf-GST-4/GST-5/GST-7 required for the control of oxidative stress was identified to act downstream of let-7 to regulate the toxicity of simulated microgravity. Our data demonstrated the crucial function of miRNAs in regulating the toxicity of simulated microgravity stress in organisms. Moreover, our results further provided an important molecular basis for epigenetic control of toxicity of simulated microgravity.

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A Family of K+ Channel Ancillary Subunits Regulate Taste Sensitivity in Caenorhabditis elegans

Journal of Biological Chemistry ◽

10.1074/jbc.m502732200 ◽

2005 ◽

Vol 280 (23) ◽

pp. 21893-21899 ◽

Cited By ~ 16

Author(s):

Ki Ho Park ◽

Leonardo Hernandez ◽

Shi-Qing Cai ◽

Yi Wang ◽

Federico Sesti

Keyword(s):

Caenorhabditis Elegans ◽

Mammalian Cells ◽

K Channel ◽

Sensory Thresholds ◽

Test Plate ◽

Double Stranded Rna ◽

Voltage Gated ◽

C Elegans ◽

Chemosensory Neuron

We have identified a family of ancillary subunits of K+ channels in Caenorhabditis elegans. MPS-1 and its related members MPS-2, MPS-3, and MPS-4 are detected in the nervous system of the nematode. Electrophysiological analysis in ASE neurons and mammalian cells and epigenetic inactivation by double-stranded RNA interference (RNAi) in vivo show that each MPS can associate with and functionally endow the voltage-gated K+ channel KVS-1. In the chemosensory neuron ADF, three different MPS subunits combine with KVS-1 to form both binary (MPS-1·KVS-1) and ternary (MPS-2·MPS-3·KVS-1) complexes. RNAi of mps-2, mps-3, or both, enhance the taste of the animal for sodium without altering the susceptibility to other attractants. When sodium is introduced in the test plate as background or as antagonist attractant, the nematode loses the ability to recognize a second attractant. Thus, it appears that the chemosensory apparatus of C. elegans uses sensory thresholds and that a voltage-gated K+ channel is specifically required for this mechanism.

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