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Kuhara A, Takagaki N, Okahata M, Ohta A. Cold Tolerance in the Nematode Caenorhabditis elegans. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1461:33-46. [PMID: 39289272 DOI: 10.1007/978-981-97-4584-5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Organisms receive environmental information and respond accordingly in order to survive and proliferate. Temperature is the environmental factor of most immediate importance, as exceeding its life-supporting range renders essential biochemical reactions impossible. In this chapter, we introduce the mechanisms underlying cold tolerance and temperature acclimation in a model organism-the nematode Caenorhabditis elegans, at molecular and physiological levels. Recent investigations utilizing molecular genetics and neural calcium imaging have unveiled a novel perspective on cold tolerance within the nematode worm. Notably, the ASJ neuron, previously known to possess photosensitive properties, has been found to sense temperature and regulate the sperm and gut cell-mediated pathway underlying cold tolerance. We will also explore C. elegans' cold tolerance and cold acclimation at the molecular and tissue levels.
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Affiliation(s)
- Atsushi Kuhara
- Faculty of Science and Engineering, Graduate School of Natural Science, Institute for Integrative Neurobiology, Konan University, Okamoto, Higashinada-ku, Kobe, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Natsune Takagaki
- Faculty of Science and Engineering, Graduate School of Natural Science, Institute for Integrative Neurobiology, Konan University, Okamoto, Higashinada-ku, Kobe, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Misaki Okahata
- Faculty of Science and Engineering, Graduate School of Natural Science, Institute for Integrative Neurobiology, Konan University, Okamoto, Higashinada-ku, Kobe, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Akane Ohta
- Faculty of Science and Engineering, Graduate School of Natural Science, Institute for Integrative Neurobiology, Konan University, Okamoto, Higashinada-ku, Kobe, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
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2
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van Oosten-Hawle P. Exploiting inter-tissue stress signaling mechanisms to preserve organismal proteostasis during aging. Front Physiol 2023; 14:1228490. [PMID: 37469564 PMCID: PMC10352849 DOI: 10.3389/fphys.2023.1228490] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 06/26/2023] [Indexed: 07/21/2023] Open
Abstract
Aging results in a decline of cellular proteostasis capacity which culminates in the accumulation of phototoxic material, causing the onset of age-related maladies and ultimately cell death. Mechanisms that regulate proteostasis such as cellular stress response pathways sense disturbances in the proteome. They are activated to increase the expression of protein quality control components that counteract cellular damage. Utilizing invertebrate model organisms such as Caenorhabditis elegans, it has become increasingly evident that the regulation of proteostasis and the activation of cellular stress responses is not a cell autonomous process. In animals, stress responses are orchestrated by signals coming from other tissues, including the nervous system, the intestine and the germline that have a profound impact on determining the aging process. Genetic pathways discovered in C. elegans that facilitate cell nonautonomous regulation of stress responses are providing an exciting feeding ground for new interventions. In this review I will discuss cell nonautonomous proteostasis mechanisms and their impact on aging as well as ongoing research and clinical trials that can increase organismal proteostasis to lengthen health- and lifespan.
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Shimada Y, Hasegawa Y, Harada Y, Nakamura R, Matsuoka T, Arikawa M. Signaling in temperature-induced resting cyst formation in the ciliated protozoan Colpoda cucullus. Eur J Protistol 2021; 79:125800. [PMID: 34049128 DOI: 10.1016/j.ejop.2021.125800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 11/29/2022]
Abstract
The terrestrial ciliated protozoan Colpoda cucullus inhabits soil. When the habitat conditions become unfavorable, the vegetative cells of C. cucullus quickly transform into resting cysts. C. cucullus culture is established in our laboratory, and encystment is routinely induced by the addition of Ca2+ to overpopulated vegetative cells. However, an increase in Ca2+ concentration and overpopulation of vegetative cells do not always occur in natural. We investigated the effect of temperature and found that cyst formation was induced by a rapid increase of 5 °C within 2 min but not by a decrease. Moreover, an increase in intracellular Ca2+ concentrations is essential, but Ca2+ inflow does not necessarily occur during encystment. Ca2+ image analysis showed that Ca2+ is stored in vesicular structures and released into the cytoplasm within 60 s after temperature stimulation. Multiple signaling pathways are activated after the release of Ca2+ from vesicles, and cAMP is a candidate second messenger with a crucial role in the process of temperature-induced encystment. Further studies are needed to clarify the mechanism underlying the sensing of temperature and release of Ca2+ from vesicles.
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Affiliation(s)
- Yuto Shimada
- Graduate School of Integrated Arts and Sciences, Applied Science Program, Kochi University, Kochi, Japan
| | - Yuya Hasegawa
- Graduate School of Integrated Arts and Sciences, Applied Science Program, Kochi University, Kochi, Japan
| | - Yuya Harada
- Graduate School of Integrated Arts and Sciences, Applied Science Program, Kochi University, Kochi, Japan
| | - Rikiya Nakamura
- Graduate School of Integrated Arts and Sciences, Applied Science Program, Kochi University, Kochi, Japan
| | - Tatsuomi Matsuoka
- Department of Biological Sciences, Faculty of Science and Technology, Kochi University, Kochi, Japan
| | - Mikihiko Arikawa
- Department of Biological Sciences, Faculty of Science and Technology, Kochi University, Kochi, Japan.
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Metaxakis A, Petratou D, Tavernarakis N. Multimodal sensory processing in Caenorhabditis elegans. Open Biol 2018; 8:180049. [PMID: 29925633 PMCID: PMC6030117 DOI: 10.1098/rsob.180049] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022] Open
Abstract
Multisensory integration is a mechanism that allows organisms to simultaneously sense and understand external stimuli from different modalities. These distinct signals are transduced into neuronal signals that converge into decision-making neuronal entities. Such decision-making centres receive information through neuromodulators regarding the organism's physiological state and accordingly trigger behavioural responses. Despite the importance of multisensory integration for efficient functioning of the nervous system, and also the implication of dysfunctional multisensory integration in the aetiology of neuropsychiatric disease, little is known about the relative molecular mechanisms. Caenorhabditis elegans is an appropriate model system to study such mechanisms and elucidate the molecular ways through which organisms understand external environments in an accurate and coherent fashion.
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Affiliation(s)
- Athanasios Metaxakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
| | - Dionysia Petratou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, Heraklion 70013, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion 71110, Crete, Greece
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Yoon S, Piao H, Jeon TJ, Kim SM. Microfluidic Platform for Analyzing the Thermotaxis of C. elegans in a Linear Temperature Gradient. ANAL SCI 2017; 33:1435-1440. [PMID: 29225236 DOI: 10.2116/analsci.33.1435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Caenorhabditis elegans (C. elegans), which shares a considerable amount of characteristics with human genes is one of the important model organisms for the study of behavioral responses. Thermotaxis is a representative behavior response of C. elegans; C. elegans stores the cultivation temperature in thermosensory neurons and moves to the cultivation temperature region in a temperature variation. In this study, we developed a microfluidic system for effective thermotaxis analysis of C. elegans. The microfluidic channel was fabricated using polydimethylsiloxane (PDMS) by soft lithography process. The temperature gradient (15 - 20°C) was generated in the microchannel and controlled by Peltier modules attached to the bottom of the channel. The thermotaxis of wild type (N2), tax-4(p678) and ttx-7(nj50) mutants were effectively analyzed using this microfluidic system. We believe that this system can be employed as a basic platform for studying the neural circuit of C. elegans responding to external stimuli.
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Affiliation(s)
- Sunhee Yoon
- Department of Biological Engineering, Inha University.,WCSL of Integrated Human Airway-on-a-Chip, Inha University
| | - Hailing Piao
- Department of Mechanical Engineering, Inha University
| | - Tae-Joon Jeon
- Department of Biological Engineering, Inha University.,WCSL of Integrated Human Airway-on-a-Chip, Inha University
| | - Sun Min Kim
- WCSL of Integrated Human Airway-on-a-Chip, Inha University.,Department of Mechanical Engineering, Inha University
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A Calcium- and Diacylglycerol-Stimulated Protein Kinase C (PKC), Caenorhabditis elegans PKC-2, Links Thermal Signals to Learned Behavior by Acting in Sensory Neurons and Intestinal Cells. Mol Cell Biol 2017; 37:MCB.00192-17. [PMID: 28716951 DOI: 10.1128/mcb.00192-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/07/2017] [Indexed: 12/18/2022] Open
Abstract
Ca2+- and diacylglycerol (DAG)-activated protein kinase C (cPKC) promotes learning and behavioral plasticity. However, knowledge of in vivo regulation and exact functions of cPKCs that affect behavior is limited. We show that PKC-2, a Caenorhabditis elegans cPKC, is essential for a complex behavior, thermotaxis. C. elegans memorizes a nutrient-associated cultivation temperature (Tc ) and migrates along the Tc within a 17 to 25°C gradient. pkc-2 gene disruption abrogated thermotaxis; a PKC-2 transgene, driven by endogenous pkc-2 promoters, restored thermotaxis behavior in pkc-2-/- animals. Cell-specific manipulation of PKC-2 activity revealed that thermotaxis is controlled by cooperative PKC-2-mediated signaling in both AFD sensory neurons and intestinal cells. Cold-directed migration (cryophilic drive) precedes Tc tracking during thermotaxis. Analysis of temperature-directed behaviors elicited by persistent PKC-2 activation or inhibition in AFD (or intestine) disclosed that PKC-2 regulates initiation and duration of cryophilic drive. In AFD neurons, PKC-2 is a Ca2+ sensor and signal amplifier that operates downstream from cyclic GMP-gated cation channels and distal guanylate cyclases. UNC-18, which regulates neurotransmitter and neuropeptide release from synaptic vesicles, is a critical PKC-2 effector in AFD. UNC-18 variants, created by mutating Ser311 or Ser322, disrupt thermotaxis and suppress PKC-2-dependent cryophilic migration.
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Behl M, Rice JR, Smith MV, Co CA, Bridge MF, Hsieh JH, Freedman JH, Boyd WA. Editor's Highlight: Comparative Toxicity of Organophosphate Flame Retardants and Polybrominated Diphenyl Ethers to Caenorhabditis elegans. Toxicol Sci 2016; 154:241-252. [PMID: 27566445 DOI: 10.1093/toxsci/kfw162] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
With the phasing-out of the polybrominated diphenyl ether (PBDE) flame retardants due to concerns regarding their potential developmental toxicity, the use of replacement compounds such as organophosphate flame retardants (OPFRs) has increased. Limited toxicity data are currently available to estimate the potential adverse health effects of the OPFRs. The toxicological effects of 4 brominated flame retardants, including 3 PBDEs and 3,3',5,5'-tetrabromobisphenol A, were compared with 6 aromatic OPFRs and 2 aliphatic OPFRs. The effects of these chemicals were determined using 3 biological endpoints in the nematode Caenorhabditis elegans (feeding, larval development, and reproduction). Because C. elegans development was previously reported to be sensitive to mitochondrial function, results were compared with those from an in vitro mitochondrial membrane permeabilization (MMP) assay. Overall 11 of the 12 flame retardants were active in 1 or more C. elegans biological endpoints, with only tris(2-chloroethyl) phosphate inactive across all endpoints including the in vitro MMP assay. For 2 of the C. elegans endpoints, at least 1 OPFR had similar toxicity to the PBDEs: triphenyl phosphate (TPHP) inhibited larval development at levels comparable to the 3 PBDEs; whereas TPHP and isopropylated phenol phosphate (IPP) affected C. elegans reproduction at levels similar to the PBDE commercial mixture, DE-71. The PBDEs reduced C. elegans feeding at lower concentrations than any OPFR. In addition, 9 of the 11 chemicals that inhibited C. elegans larval development also caused significant mitochondrial toxicity. These results suggest that some of the replacement aromatic OPFRs may have levels of toxicity comparable to PBDEs.
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Affiliation(s)
- Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina
| | - Julie R Rice
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina
| | - Marjo V Smith
- Social & Scientific Systems, Inc., Durham, North Carolina
| | - Caroll A Co
- Social & Scientific Systems, Inc., Durham, North Carolina
| | | | - Jui-Hua Hsieh
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina
| | - Jonathan H Freedman
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Windy A Boyd
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina
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8
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Todd PAC, McCue HV, Haynes LP, Barclay JW, Burgoyne RD. Interaction of ARF-1.1 and neuronal calcium sensor-1 in the control of the temperature-dependency of locomotion in Caenorhabditis elegans. Sci Rep 2016; 6:30023. [PMID: 27435667 PMCID: PMC4951722 DOI: 10.1038/srep30023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/27/2016] [Indexed: 12/15/2022] Open
Abstract
Neuronal calcium sensor-1 (NCS-1) mediates changes in cellular function by regulating various target proteins. Many potential targets have been identified but the physiological significance of only a few has been established. Upon temperature elevation, Caenorhabditis elegans exhibits reversible paralysis. In the absence of NCS-1, worms show delayed onset and a shorter duration of paralysis. This phenotype can be rescued by re-expression of ncs-1 in AIY neurons. Mutants with defects in four potential NCS-1 targets (arf-1.1, pifk-1, trp-1 and trp-2) showed qualitatively similar phenotypes to ncs-1 null worms, although the effect of pifk-1 mutation on time to paralysis was considerably delayed. Inhibition of pifk-1 also resulted in a locomotion phenotype. Analysis of double mutants showed no additive effects between mutations in ncs-1 and trp-1 or trp-2. In contrast, double mutants of arf-1.1 and ncs-1 had an intermediate phenotype, consistent with NCS-1 and ARF-1.1 acting in the same pathway. Over-expression of arf-1.1 in the AIY neurons was sufficient to rescue partially the phenotype of both the arf-1.1 and the ncs-1 null worms. These findings suggest that ARF-1.1 interacts with NCS-1 in AIY neurons and potentially pifk-1 in the Ca(2+) signaling pathway that leads to inhibited locomotion at an elevated temperature.
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Affiliation(s)
- Paul A. C. Todd
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
| | - Hannah V. McCue
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
| | - Lee P. Haynes
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
| | - Jeff W. Barclay
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
| | - Robert D. Burgoyne
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
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9
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Gouvêa DY, Aprison EZ, Ruvinsky I. Experience Modulates the Reproductive Response to Heat Stress in C. elegans via Multiple Physiological Processes. PLoS One 2015; 10:e0145925. [PMID: 26713620 PMCID: PMC4699941 DOI: 10.1371/journal.pone.0145925] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/10/2015] [Indexed: 11/29/2022] Open
Abstract
Natural environments are considerably more variable than laboratory settings and often involve transient exposure to stressful conditions. To fully understand how organisms have evolved to respond to any given stress, prior experience must therefore be considered. We investigated the effects of individual and ancestral experience on C. elegans reproduction. We documented ways in which cultivation at 15°C or 25°C affects developmental time, lifetime fecundity, and reproductive performance after severe heat stress that exceeds the fertile range of the organism but is compatible with survival and future fecundity. We found that experience modulates multiple aspects of reproductive physiology, including the male and female germ lines and the interaction between them. These responses vary in their environmental sensitivity, suggesting the existence of complex mechanisms for coping with unpredictable and stressful environments.
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Affiliation(s)
- Devin Y. Gouvêa
- Committee on Conceptual and Historical Studies of Science, The University of Chicago, Chicago, Illinois, United States of America
- Committee on Evolutionary Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Erin Z. Aprison
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
| | - Ilya Ruvinsky
- Committee on Evolutionary Biology, The University of Chicago, Chicago, Illinois, United States of America
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois, United States of America
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Wu T, He K, Zhan Q, Ang S, Ying J, Zhang S, Zhang T, Xue Y, Tang M. MPA-capped CdTe quantum dots exposure causes neurotoxic effects in nematode Caenorhabditis elegans by affecting the transporters and receptors of glutamate, serotonin and dopamine at the genetic level, or by increasing ROS, or both. NANOSCALE 2015; 7:20460-20473. [PMID: 26583374 DOI: 10.1039/c5nr05914c] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
As quantum dots (QDs) are widely used in biomedical applications, the number of studies focusing on their biological properties is increasing. While several studies have attempted to evaluate the toxicity of QDs towards neural cells, the in vivo toxic effects on the nervous system and the molecular mechanisms are unclear. The aim of the present study was to investigate the neurotoxic effects and the underlying mechanisms of water-soluble cadmium telluride (CdTe) QDs capped with 3-mercaptopropionic acid (MPA) in Caenorhabditis elegans (C. elegans). Our results showed that exposure to MPA-capped CdTe QDs induced behavioral defects, including alterations to body bending, head thrashing, pharyngeal pumping and defecation intervals, as well as impaired learning and memory behavior plasticity, based on chemotaxis or thermotaxis, in a dose-, time- and size-dependent manner. Further investigations suggested that MPA-capped CdTe QDs exposure inhibited the transporters and receptors of glutamate, serotonin and dopamine in C. elegans at the genetic level within 24 h, while opposite results were observed after 72 h. Additionally, excessive reactive oxygen species (ROS) generation was observed in the CdTe QD-treated worms, which confirmed the common nanotoxicity mechanism of oxidative stress damage, and might overcome the increased gene expression of neurotransmitter transporters and receptors in C. elegans induced by long-term QD exposure, resulting in more severe behavioral impairments.
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Affiliation(s)
- Tianshu Wu
- Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, & Collaborative Innovation Center of Suzhou Nano Science and Technology, Southeast University, Nanjing 210009, China.
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Sonogenetics is a non-invasive approach to activating neurons in Caenorhabditis elegans. Nat Commun 2015; 6:8264. [PMID: 26372413 PMCID: PMC4571289 DOI: 10.1038/ncomms9264] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 08/04/2015] [Indexed: 12/30/2022] Open
Abstract
A major challenge in neuroscience is to reliably activate individual neurons, particularly those in deeper brain regions. Current optogenetic approaches require invasive surgical procedures to deliver light of specific wavelengths to target cells to activate or silence them. Here, we demonstrate the use of low-pressure ultrasound as a non-invasive trigger to activate specific ultrasonically sensitized neurons in the nematode, Caenorhabditis elegans. We first show that wild-type animals are insensitive to low-pressure ultrasound and require gas-filled microbubbles to transduce the ultrasound wave. We find that neuron-specific misexpression of TRP-4, the pore-forming subunit of a mechanotransduction channel, sensitizes neurons to ultrasound stimulus, resulting in behavioural outputs. Furthermore, we use this approach to manipulate the function of sensory neurons and interneurons and identify a role for PVD sensory neurons in modifying locomotory behaviours. We suggest that this method can be broadly applied to manipulate cellular functions in vivo. Common optogenetic approaches require surgical procedures to deliver light of specific wavelengths to the target cells. Here the authors demonstrate the use of low-pressure ultrasound as a non-invasive trigger to activate specific neurons in Caenorhabditis elegans and find that the mechanotransduction channel TRP-4 sensitizes cells to the ultrasound stimulus.
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12
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Thermosensation and longevity. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:857-67. [PMID: 26101089 DOI: 10.1007/s00359-015-1021-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 06/06/2015] [Accepted: 06/08/2015] [Indexed: 12/25/2022]
Abstract
Temperature has profound effects on behavior and aging in both poikilotherms and homeotherms. To thrive under the ever fluctuating environmental temperatures, animals have evolved sophisticated mechanisms to sense and adapt to temperature changes. Animals sense temperature through various molecular thermosensors, such as thermosensitive transient receptor potential (TRP) channels expressed in neurons, keratinocytes, and intestine. These evolutionarily conserved thermosensitive TRP channels feature distinct activation thresholds, thereby covering a wide spectrum of ambient temperature. Temperature changes trigger complex thermosensory behaviors. Due to the simplicity of the nervous system in model organisms such as Caenorhabditis elegans and Drosophila, the mechanisms of thermosensory behaviors in these species have been extensively studied at the circuit and molecular levels. While much is known about temperature regulation of behavior, it remains largely unclear how temperature affects aging. Recent studies in C. elegans demonstrate that temperature modulation of longevity is not simply a passive thermodynamic phenomenon as suggested by the rate-of-living theory, but rather a process that is actively regulated by genes, including those encoding thermosensitive TRP channels. In this review, we discuss our current understanding of thermosensation and its role in aging.
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Directional Trans-Synaptic Labeling of Specific Neuronal Connections in Live Animals. Genetics 2015; 200:697-705. [PMID: 25917682 DOI: 10.1534/genetics.115.177006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/24/2015] [Indexed: 11/18/2022] Open
Abstract
Understanding animal behavior and development requires visualization and analysis of their synaptic connectivity, but existing methods are laborious or may not depend on trans-synaptic interactions. Here we describe a transgenic approach for in vivo labeling of specific connections in Caenorhabditis elegans, which we term iBLINC. The method is based on BLINC (Biotin Labeling of INtercellular Contacts) and involves trans-synaptic enzymatic transfer of biotin by the Escherichia coli biotin ligase BirA onto an acceptor peptide. A BirA fusion with the presynaptic cell adhesion molecule NRX-1/neurexin is expressed presynaptically, whereas a fusion between the acceptor peptide and the postsynaptic protein NLG-1/neuroligin is expressed postsynaptically. The biotinylated acceptor peptide::NLG-1/neuroligin fusion is detected by a monomeric streptavidin::fluorescent protein fusion transgenically secreted into the extracellular space. Physical contact between neurons is insufficient to create a fluorescent signal, suggesting that synapse formation is required. The labeling approach appears to capture the directionality of synaptic connections, and quantitative analyses of synapse patterns display excellent concordance with electron micrograph reconstructions. Experiments using photoconvertible fluorescent proteins suggest that the method can be utilized for studies of protein dynamics at the synapse. Applying this technique, we find connectivity patterns of defined connections to vary across a population of wild-type animals. In aging animals, specific segments of synaptic connections are more susceptible to decline than others, consistent with dedicated mechanisms of synaptic maintenance. Collectively, we have developed an enzyme-based, trans-synaptic labeling method that allows high-resolution analyses of synaptic connectivity as well as protein dynamics at specific synapses of live animals.
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Jalles A, 1 Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4710-057 Braga, Portugal;, Maciel P. The disruption of proteostasis in neurodegenerative disorders. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.3.259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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15
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van Oosten-Hawle P, Morimoto RI. Transcellular chaperone signaling: an organismal strategy for integrated cell stress responses. ACTA ACUST UNITED AC 2014; 217:129-36. [PMID: 24353212 DOI: 10.1242/jeb.091249] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability of each cell within a metazoan to adapt to and survive environmental and physiological stress requires cellular stress-response mechanisms, such as the heat shock response (HSR). Recent advances reveal that cellular proteostasis and stress responses in metazoans are regulated by multiple layers of intercellular communication. This ensures that an imbalance of proteostasis that occurs within any single tissue 'at risk' is protected by a compensatory activation of a stress response in adjacent tissues that confers a community protective response. While each cell expresses the machinery for heat shock (HS) gene expression, the HSR is regulated cell non-autonomously in multicellular organisms, by neuronal signaling to the somatic tissues, and by transcellular chaperone signaling between somatic tissues and from somatic tissues to neurons. These cell non-autonomous processes ensure that the organismal HSR is orchestrated across multiple tissues and that transmission of stress signals between tissues can also override the neuronal control to reset cell- and tissue-specific proteostasis. Here, we discuss emerging concepts and insights into the complex cell non-autonomous mechanisms that control stress responses in metazoans and highlight the importance of intercellular communication for proteostasis maintenance in multicellular organisms.
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Affiliation(s)
- Patricija van Oosten-Hawle
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA
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16
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Yu CW, Liao VHC. Arsenite induces neurotoxic effects on AFD neurons via oxidative stress in Caenorhabditis elegans. Metallomics 2014; 6:1824-31. [DOI: 10.1039/c4mt00160e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Humidity sensation requires both mechanosensory and thermosensory pathways in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2014; 111:8269-74. [PMID: 24843133 DOI: 10.1073/pnas.1322512111] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
All terrestrial animals must find a proper level of moisture to ensure their health and survival. The cellular-molecular basis for sensing humidity is unknown in most animals, however. We used the model nematode Caenorhabditis elegans to uncover a mechanism for sensing humidity. We found that whereas C. elegans showed no obvious preference for humidity levels under standard culture conditions, worms displayed a strong preference after pairing starvation with different humidity levels, orienting to gradients as shallow as 0.03% relative humidity per millimeter. Cell-specific ablation and rescue experiments demonstrate that orientation to humidity in C. elegans requires the obligatory combination of distinct mechanosensitive and thermosensitive pathways. The mechanosensitive pathway requires a conserved DEG/ENaC/ASIC mechanoreceptor complex in the FLP neuron pair. Because humidity levels influence the hydration of the worm's cuticle, our results suggest that FLP may convey humidity information by reporting the degree that subcuticular dendritic sensory branches of FLP neurons are stretched by hydration. The thermosensitive pathway requires cGMP-gated channels in the AFD neuron pair. Because humidity levels affect evaporative cooling, AFD may convey humidity information by reporting thermal flux. Thus, humidity sensation arises as a metamodality in C. elegans that requires the integration of parallel mechanosensory and thermosensory pathways. This hygrosensation strategy, first proposed by Thunberg more than 100 y ago, may be conserved because the underlying pathways have cellular and molecular equivalents across a wide range of species, including insects and humans.
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Bidirectional thermotaxis in Caenorhabditis elegans is mediated by distinct sensorimotor strategies driven by the AFD thermosensory neurons. Proc Natl Acad Sci U S A 2014; 111:2776-81. [PMID: 24550307 DOI: 10.1073/pnas.1315205111] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nematode Caenorhabditis elegans navigates toward a preferred temperature setpoint (Ts) determined by long-term temperature exposure. During thermotaxis, the worm migrates down temperature gradients at temperatures above Ts (negative thermotaxis) and performs isothermal tracking near Ts. Under some conditions, the worm migrates up temperature gradients below Ts (positive thermotaxis). Here, we analyze positive and negative thermotaxis toward Ts to study the role of specific neurons that have been proposed to be involved in thermotaxis using genetic ablation, behavioral tracking, and calcium imaging. We find differences in the strategies for positive and negative thermotaxis. Negative thermotaxis is achieved through biasing the frequency of reorientation maneuvers (turns and reversal turns) and biasing the direction of reorientation maneuvers toward colder temperatures. Positive thermotaxis, in contrast, biases only the direction of reorientation maneuvers toward warmer temperatures. We find that the AFD thermosensory neuron drives both positive and negative thermotaxis. The AIY interneuron, which is postsynaptic to AFD, may mediate the switch from negative to positive thermotaxis below Ts. We propose that multiple thermotactic behaviors, each defined by a distinct set of sensorimotor transformations, emanate from the AFD thermosensory neurons. AFD learns and stores the memory of preferred temperatures, detects temperature gradients, and drives the appropriate thermotactic behavior in each temperature regime by the flexible use of downstream circuits.
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Kodama-Namba E, Fenk LA, Bretscher AJ, Gross E, Busch KE, de Bono M. Cross-modulation of homeostatic responses to temperature, oxygen and carbon dioxide in C. elegans. PLoS Genet 2013; 9:e1004011. [PMID: 24385919 PMCID: PMC3868554 DOI: 10.1371/journal.pgen.1004011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 10/24/2013] [Indexed: 11/19/2022] Open
Abstract
Different interoceptive systems must be integrated to ensure that multiple homeostatic insults evoke appropriate behavioral and physiological responses. Little is known about how this is achieved. Using C. elegans, we dissect cross-modulation between systems that monitor temperature, O₂ and CO₂. CO₂ is less aversive to animals acclimated to 15°C than those grown at 22°C. This difference requires the AFD neurons, which respond to both temperature and CO₂ changes. CO₂ evokes distinct AFD Ca²⁺ responses in animals acclimated at 15°C or 22°C. Mutants defective in synaptic transmission can reprogram AFD CO₂ responses according to temperature experience, suggesting reprogramming occurs cell autonomously. AFD is exquisitely sensitive to CO₂. Surprisingly, gradients of 0.01% CO₂/second evoke very different Ca²⁺ responses from gradients of 0.04% CO₂/second. Ambient O₂ provides further contextual modulation of CO₂ avoidance. At 21% O₂ tonic signalling from the O₂-sensing neuron URX inhibits CO₂ avoidance. This inhibition can be graded according to O₂ levels. In a natural wild isolate, a switch from 21% to 19% O₂ is sufficient to convert CO₂ from a neutral to an aversive cue. This sharp tuning is conferred partly by the neuroglobin GLB-5. The modulatory effects of O₂ on CO₂ avoidance involve the RIA interneurons, which are post-synaptic to URX and exhibit CO₂-evoked Ca²⁺ responses. Ambient O₂ and acclimation temperature act combinatorially to modulate CO₂ responsiveness. Our work highlights the integrated architecture of homeostatic responses in C. elegans.
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Affiliation(s)
| | - Lorenz A. Fenk
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Einav Gross
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Mario de Bono
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- * E-mail:
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Tseng IL, Yang YF, Yu CW, Li WH, Liao VHC. Phthalates induce neurotoxicity affecting locomotor and thermotactic behaviors and AFD neurons through oxidative stress in Caenorhabditis elegans. PLoS One 2013; 8:e82657. [PMID: 24349328 PMCID: PMC3861438 DOI: 10.1371/journal.pone.0082657] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 10/25/2013] [Indexed: 01/05/2023] Open
Abstract
Background Phthalate esters are ubiquitous environmental contaminants and numerous organisms are thus exposed to various levels of phthalates in their natural habitat. Considering the critical, but limited, research on human neurobehavioral outcomes in association with phthalates exposure, we used the nematode Caenorhabditis elegans as an in vivo model to evaluate phthalates-induced neurotoxicity and the possible associated mechanisms. Principal Findings Exposure to phthalates (DEHP, DBP, and DIBP) at the examined concentrations induced behavioral defects, including changes in body bending, head thrashing, reversal frequency, and thermotaxis in C. elegans. Moreover, phthalates (DEHP, DBP, and DIBP) exposure caused toxicity, affecting the relative sizes of cell body fluorescent puncta, and relative intensities of cell bodies in AFD neurons. The mRNA levels of the majority of the genes (TTX-1, TAX-2, TAX-4, and CEH-14) that are required for the differentiation and function of AFD neurons were decreased upon DEHP exposure. Furthermore, phthalates (DEHP, DBP, and DIBP) exposure at the examined concentrations produced elevated intracellular reactive oxygen species (ROS) in C. elegans. Finally, pretreatment with the antioxidant ascorbic acid significantly lowered the intracellular ROS level, ameliorated the locomotor and thermotactic behavior defects, and protected the damage of AFD neurons by DEHP exposure. Conclusions Our study suggests that oxidative stress plays a critical role in the phthalate esters-induced neurotoxic effects in C. elegans.
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Affiliation(s)
- I-Ling Tseng
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Ying-Fei Yang
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Chan-Wei Yu
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Wen-Hsuan Li
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
| | - Vivian Hsiu-Chuan Liao
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Sasakura H, Tsukada Y, Takagi S, Mori I. Japanese studies on neural circuits and behavior of Caenorhabditis elegans. Front Neural Circuits 2013; 7:187. [PMID: 24348340 PMCID: PMC3842693 DOI: 10.3389/fncir.2013.00187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 11/03/2013] [Indexed: 01/25/2023] Open
Abstract
The nematode Caenorhabditis elegans is an ideal organism for studying neural plasticity and animal behaviors. A total of 302 neurons of a C. elegans hermaphrodite have been classified into 118 neuronal groups. This simple neural circuit provides a solid basis for understanding the mechanisms of the brains of higher animals, including humans. Recent studies that employ modern imaging and manipulation techniques enable researchers to study the dynamic properties of nervous systems with great precision. Behavioral and molecular genetic analyses of this tiny animal have contributed greatly to the advancement of neural circuit research. Here, we will review the recent studies on the neural circuits of C. elegans that have been conducted in Japan. Several laboratories have established unique and clever methods to study the underlying neuronal substrates of behavioral regulation in C. elegans. The technological advances applied to studies of C. elegans have allowed new approaches for the studies of complex neural systems. Through reviewing the studies on the neuronal circuits of C. elegans in Japan, we will analyze and discuss the directions of neural circuit studies.
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Affiliation(s)
- Hiroyuki Sasakura
- Laboratory of Molecular Neurobiology, Division of Biological Science, Nagoya University Nagoya, Japan
| | - Yuki Tsukada
- Laboratory of Molecular Neurobiology, Division of Biological Science, Nagoya University Nagoya, Japan
| | - Shin Takagi
- Laboratory of Brain Function and Structure, Division of Biological Science, Nagoya University Nagoya, Japan
| | - Ikue Mori
- Laboratory of Molecular Neurobiology, Division of Biological Science, Nagoya University Nagoya, Japan
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Glauser DA. How and why Caenorhabditis elegans uses distinct escape and avoidance regimes to minimize exposure to noxious heat. WORM 2013; 2:e27285. [PMID: 24744986 DOI: 10.4161/worm.27285] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/13/2013] [Accepted: 11/20/2013] [Indexed: 02/02/2023]
Abstract
Minimizing the exposure to deleterious extremes of temperature is essential for animals to avoid tissue damages. Because their body temperature equilibrates very rapidly with their surroundings, small invertebrates are particularly vulnerable to the deleterious impact of high temperatures, which jeopardizes their growth, fertility, and survival. The present article reviews recent analyses of Caenorhabditis elegans behavior in temperature gradients covering innocuous and noxious temperatures. These analyses have highlighted that worm uses two separate, multi-componential navigational strategies: an avoidance strategy, aiming at staying away from noxious heat, and an escape strategy, aiming at running away after exposure. Here, I explain why efficient escape and avoidance mechanisms are mutually exclusive and why worm needs to switch between distinct behavioral regimes to achieve efficient protective thermoregulation. Collectively, these findings reveal some largely unrecognized strategies improving worm goal-directed navigation and the fascinating level of sophistication of the behavioral responses deployed to minimize the exposure to noxious heat. Because switching between avoidance and escape regimes circumvents constraints that are valid for navigation behaviors in general, similar solutions might be used by worms and also other organisms in response to various environmental parameters covering an innocuous/noxious, non-toxic/toxic range.
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Affiliation(s)
- Dominique A Glauser
- Department of Biology; University of Fribourg; Chemin du Musée 10; Fribourg, Switzerland
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Serotonin control of thermotaxis memory behavior in nematode Caenorhabditis elegans. PLoS One 2013; 8:e77779. [PMID: 24223727 PMCID: PMC3815336 DOI: 10.1371/journal.pone.0077779] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/12/2013] [Indexed: 11/26/2022] Open
Abstract
Caenorhabditis elegans is as an ideal model system for the study of mechanisms underlying learning and memory. In the present study, we employed C. elegans assay system of thermotaxis memory to investigate the possible role of serotonin neurotransmitter in memory control. Our data showed that both mutations of tph-1, bas-1, and cat-4 genes, required for serotonin synthesis, and mutations of mod-5 gene, encoding a serotonin reuptake transporter, resulted in deficits in thermotaxis memory behavior. Exogenous treatment with serotonin effectively recovered the deficits in thermotaxis memory of tph-1 and bas-1 mutants to the level of wild-type N2. Neuron-specific activity assay of TPH-1 suggests that serotonin might regulate the thermotaxis memory behavior by release from the ADF sensory neurons. Ablation of ADF sensory neurons by expressing a cell-death activator gene egl-1 decreased the thermotaxis memory, whereas activation of ADF neurons by expression of a constitutively active protein kinase C homologue (pkc-1(gf)) increased the thermotaxis memory and rescued the deficits in thermotaxis memory in tph-1 mutants. Moreover, serotonin released from the ADF sensory neurons might act through the G-protein-coupled serotonin receptors of SER-4 and SER-7 to regulate the thermotaxis memory behavior. Genetic analysis implies that serotonin might further target the insulin signaling pathway to regulate the thermotaxis memory behavior. Thus, our results suggest the possible crucial role of serotonin and ADF sensory neurons in thermotaxis memory control in C. elegans.
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Gözen I, Shaali M, Ainla A, Örtmen B, Põldsalu I, Kustanovich K, Jeffries GDM, Konkoli Z, Dommersnes P, Jesorka A. Thermal migration of molecular lipid films as a contactless fabrication strategy for lipid nanotube networks. LAB ON A CHIP 2013; 13:3822-3826. [PMID: 23903381 DOI: 10.1039/c3lc50391g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate the contactless generation of lipid nanotube networks by means of thermally induced migration of flat giant unilamellar vesicles (FGUVs), covering micro-scale areas on oxidized aluminum surfaces. A temperature gradient with a reach of 20 μm was generated using a focused IR laser, leading to a surface adhesion gradient, along which FGUVs could be relocated. We report on suitable lipid-substrate combinations, highlighting the critical importance of the electrostatic interactions between the engineered substrate and the membrane for reversible migration of intact vesicles.
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Affiliation(s)
- Irep Gözen
- Chalmers University of Technology, Göteborg, SE-412 96, Sweden.
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Kimata T, Sasakura H, Ohnishi N, Nishio N, Mori I. Thermotaxis of C. elegans as a model for temperature perception, neural information processing and neural plasticity. WORM 2013; 1:31-41. [PMID: 24058821 PMCID: PMC3670169 DOI: 10.4161/worm.19504] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Thermotaxis is a model to elucidate how nervous systems sense and memorize environmental conditions to regulate behavioral strategies in Caenorhabditis elegans. The genetic and neural imaging analyses revealed molecular and cellular bases of this experience-dependent behavior. Surprisingly, thermosensory neurons themselves memorize the sensed temperatures. Recently developed techniques for optical manipulation of neuronal activity have facilitated the revelation that there is a sophisticated information flow between sensory neurons and interneurons. Further studies on thermotaxis will allow us to understand the fundamental logics of neural processing from sensory perceptions to behavioral outputs.
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Affiliation(s)
- Tsubasa Kimata
- Laboratory of Molecular Neurobiology; Department of Molecular Biology; Graduate School of Science; Nagoya University; Nagoya, Japan
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Martin VM, Johnson JR, Haynes LP, Barclay JW, Burgoyne RD. Identification of key structural elements for neuronal calcium sensor-1 function in the regulation of the temperature-dependency of locomotion in C. elegans. Mol Brain 2013; 6:39. [PMID: 23981466 PMCID: PMC3765893 DOI: 10.1186/1756-6606-6-39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 08/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background Intracellular Ca2+ regulates many aspects of neuronal function through Ca2+ binding to EF hand-containing Ca2+ sensors that in turn bind target proteins to regulate their function. Amongst the sensors are the neuronal calcium sensor (NCS) family of proteins that are involved in multiple neuronal signalling pathways. Each NCS protein has specific and overlapping targets and physiological functions and specificity is likely to be determined by structural features within the proteins. Common to the NCS proteins is the exposure of a hydrophobic groove, allowing target binding in the Ca2+-loaded form. Structural analysis of NCS protein complexes with target peptides has indicated common and distinct aspects of target protein interaction. Two key differences between NCS proteins are the size of the hydrophobic groove that is exposed for interaction and the role of their non-conserved C-terminal tails. Results We characterised the role of NCS-1 in a temperature-dependent locomotion assay in C. elegans and identified a distinct phenotype in the ncs-1 null in which the worms do not show reduced locomotion at actually elevated temperature. Using rescue of this phenotype we showed that NCS-1 functions in AIY neurons. Structure/function analysis introducing single or double mutations within the hydrophobic groove based on information from characterised target complexes established that both N- and C-terminal pockets of the groove are functionally important and that deletion of the C-terminal tail of NCS-1 did not impair its ability to rescue. Conclusions The current work has allowed physiological assessment of suggestions from structural studies on the key structural features that underlie the interaction of NCS-1 with its target proteins. The results are consistent with the notion that full length of the hydrophobic groove is required for the regulatory interactions underlying NCS-1 function whereas the C-terminal tail of NCS-1 is not essential. This has allowed discrimination between two potential modes of interaction of NCS-1 with its targets.
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Affiliation(s)
- Victoria M Martin
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, UK.
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Ohta A, Kuhara A. Molecular mechanism for trimetric G protein-coupled thermosensation and synaptic regulation in the temperature response circuit of Caenorhabditis elegans. Neurosci Res 2013; 76:119-24. [PMID: 23542220 DOI: 10.1016/j.neures.2013.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/01/2013] [Accepted: 03/08/2013] [Indexed: 12/18/2022]
Abstract
How the nervous system controls the sensation and memory of information from the environment is an essential question. The nematode Caenorhabditis elegans is a useful model for elucidating neural information processing that mediates sensation and memory. The entire nervous system of C. elegans consists of only 302 neurons, and their wiring diagram has been revealed by electron microscopy analysis. Here, we review the molecular and physiological mechanisms responsible for the neural circuit-mediated temperature-seeking behavior (thermotaxis) in C. elegans. Recent molecular biology studies and optogenetic analyses, such as the optical manipulation of neural activity, and neural imaging have revealed the novel concept of neural calculation. Most significantly, trimetric G proteincoupled thermosensation, single sensory neuron-based memory, and the orchestrated synaptic transmission system have been elucidated.
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Affiliation(s)
- Akane Ohta
- Laboratory of Molecular and Cellular Regulation, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
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28
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Behavioral plasticity, learning, and memory in C. elegans. Curr Opin Neurobiol 2013; 23:92-9. [DOI: 10.1016/j.conb.2012.09.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 08/31/2012] [Accepted: 09/17/2012] [Indexed: 01/02/2023]
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Ohnishi T, Tanizawa Y, Watanabe A, Nakamura T, Ohba H, Hirata H, Kaneda C, Iwayama Y, Arimoto T, Watanabe K, Mori I, Yoshikawa T. Human myo-inositol monophosphatase 2 rescues the nematode thermotaxis mutant ttx-7 more efficiently than IMPA1: functional and evolutionary considerations of the two mammalian myo-inositol monophosphatase genes. J Neurochem 2012. [PMID: 23205734 DOI: 10.1111/jnc.12112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mammals express two myo-inositol monophosphatase (IMPase) genes, IMPA1/Impa1 and IMPA2/Impa2. In this study, we compared the spatial expression patterns of the two IMPase gene transcripts and proteins in mouse tissues. Results indicated discrete expression of the two IMPase genes and their protein products in various organs, including the brain. In Caenorhabditis elegans, loss of the IMPase gene, ttx-7, disrupts cellular polarity in RIA neurons, eliciting abnormal thermotaxis behavior. We performed a rescue experiment in mutant nematodes using mammalian IMPases. Human IMPA2 rescued the abnormal behavioral phenotype in the ttx-7 mutants more efficiently than IMPA1. These results raise a question about the phylogenetic origin of IMPases and the biological roles of mammalian IMPase 2 in mammals. Impa2 knockout mice generated in our laboratory, exhibited neither behavioral abnormalities nor a significant reduction in myo-inositol content in the brain and other examined tissues. Given the ability of human IMPA2 to rescue the ttx-7 mutant, and its genetic association with multiple neuropsychiatric disorders, close scrutiny of IMPA2 function and the evolutionary origin of IMPase genes is warranted.
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Affiliation(s)
- Tetsuo Ohnishi
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Wako, Japan.
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Ghosh R, Mohammadi A, Kruglyak L, Ryu WS. Multiparameter behavioral profiling reveals distinct thermal response regimes in Caenorhabditis elegans. BMC Biol 2012; 10:85. [PMID: 23114012 PMCID: PMC3520762 DOI: 10.1186/1741-7007-10-85] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 10/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Responding to noxious stimuli by invoking an appropriate escape response is critical for survival of an organism. The sensations of small and large changes in temperature in most organisms have been studied separately in the context of thermotaxis and nociception, respectively. Here we use the nematode C. elegans to address the neurogenetic basis of responses to thermal stimuli over a broad range of intensities. RESULTS C. elegans responds to aversive temperature by eliciting a stereotypical behavioral sequence. Upon sensation of the noxious stimulus, it moves backwards, turns and resumes forward movement in a new direction. In order to study the response of C. elegans to a broad range of noxious thermal stimuli, we developed a novel assay that allows simultaneous characterization of multiple aspects of escape behavior elicited by thermal pulses of increasing amplitudes. We exposed the laboratory strain N2, as well as 47 strains with defects in various aspects of nervous system function, to thermal pulses ranging from ΔT = 0.4°C to 9.1°C and recorded the resulting behavioral profiles. CONCLUSIONS Through analysis of the multidimensional behavioral profiles, we found that the combinations of molecules shaping avoidance responses to a given thermal pulse are unique. At different intensities of aversive thermal stimuli, these distinct combinations of molecules converge onto qualitatively similar stereotyped behavioral sequences.
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Affiliation(s)
- Rajarshi Ghosh
- Lewis-Sigler Institute for Integrative Genomics, Department of Ecology and Evolutionary Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA
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Han B, Kim D, Ko UH, Shin JH. A sorting strategy for C. elegans based on size-dependent motility and electrotaxis in a micro-structured channel. LAB ON A CHIP 2012; 12:4128-34. [PMID: 22864253 DOI: 10.1039/c2lc40209b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Caenorhabditis elegans (C. elegans) is a model organism widely utilized in various fundamental studies in developmental, neural and behavioural biology. The worm features four distinct larval stages, and many research questions are stage-specific; therefore, it is necessary to sort worms by their developmental stages, which are typically represented by different size ranges. However, manually synchronizing large populations of worms is time-consuming and labour-intensive, and the commercially available automated sorter is massive and expensive. Realizing the need for a cost-effective and simple micro-platform for sorting, we report an inexpensive and novel method to accomplish this goal. The proposed micro-platform features hexagonally arrayed microstructures with geometric dimensions optimized for the maximum motility of the worms based on their sizes. In each of the optimized micro-structured platforms, only the worms with the targeted size swim continuously with the maximum undulation frequency. Additionally, the persistent and directed movement of the worms can be achieved by applying an electric field along the channel. Based on the optimally spaced microstructures and the electrotaxis behaviour of the worms, we demonstrate the feasibility of a sorting strategy of C. elegans based on their size-dependent swimming behaviour. This micro-platform can also be used for other applications, such as behavioural studies of normal and locomotion-defective mutant worms in complex structures.
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Affiliation(s)
- Bicheng Han
- Division of Mechanical Engineering, School of Mechanical, Aerospace and Systems Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseng-gu, Daejeon 305-701, Republic of Korea
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Jeong DE, Artan M, Seo K, Lee SJ. Regulation of lifespan by chemosensory and thermosensory systems: findings in invertebrates and their implications in mammalian aging. Front Genet 2012; 3:218. [PMID: 23087711 PMCID: PMC3475297 DOI: 10.3389/fgene.2012.00218] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/01/2012] [Indexed: 12/30/2022] Open
Abstract
Many environmental factors that dynamically change in nature influence various aspects of animal physiology. Animals are equipped with sensory neuronal systems that help them properly sense and respond to environmental factors. Several studies have shown that chemosensory and thermosensory neurons affect the lifespan of invertebrate model animals, including Caenorhabditis elegans and Drosophila melanogaster. Although the mechanisms by which these sensory systems modulate lifespan are incompletely understood, hormonal signaling pathways have been implicated in sensory system-mediated lifespan regulation. In this review, we describe findings regarding how sensory nervous system components elicit physiological changes to regulate lifespan in invertebrate models, and discuss their implications in mammalian aging.
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Affiliation(s)
- Dae-Eun Jeong
- Division of Molecular and Life Science, Pohang University of Science and Technology Pohang, South Korea
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PKC-2 phosphorylation of UNC-18 Ser322 in AFD neurons regulates temperature dependency of locomotion. J Neurosci 2012; 32:7042-51. [PMID: 22593072 DOI: 10.1523/jneurosci.4029-11.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Diacylglycerol (DAG)/protein kinase C (PKC) signaling plays an integral role in the regulation of neuronal function. This is certainly true in Caenorhabditis elegans and in particular for thermosensory signaling and behavior. Downstream molecular targets for transduction of this signaling cascade remain, however, virtually uncharacterized. We investigated whether PKC phosphorylation of Munc18-1, an essential protein in vesicle trafficking and exocytosis, was the downstream effector for DAG regulation of thermosensory behavior. We demonstrate here that the C. elegans ortholog of Munc18-1, UNC-18, was phosphorylated in vitro at Ser322. Transgenic rescue of unc-18-null worms with Ser322 phosphomutants displayed altered thermosensitivity. C. elegans expresses three DAG-regulated PKCs, and blocking UNC-18 Ser322 phosphorylation was phenocopied only by deletion of calcium-activated PKC-2. Expression of nonphosphorylatable UNC-18 S322A, either pan-neuronally or specifically in AFD thermosensory neurons, converted wild-type worms to a pkc-2-null phenotype. These data demonstrate that an individual DAG-dependent thermosensory behavior of an organism is effected specifically by the downstream PKC-2 phosphorylation of UNC-18 on Ser322 in AFD neurons.
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A role for α-adducin (ADD-1) in nematode and human memory. EMBO J 2012; 31:1453-66. [PMID: 22307086 DOI: 10.1038/emboj.2012.14] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/05/2012] [Indexed: 12/17/2022] Open
Abstract
Identifying molecular mechanisms that underlie learning and memory is one of the major challenges in neuroscience. Taken the advantages of the nematode Caenorhabditis elegans, we investigated α-adducin (add-1) in aversive olfactory associative learning and memory. Loss of add-1 function selectively impaired short- and long-term memory without causing acquisition, sensory, or motor deficits. We showed that α-adducin is required for consolidation of synaptic plasticity, for sustained synaptic increase of AMPA-type glutamate receptor (GLR-1) content and altered GLR-1 turnover dynamics. ADD-1, in a splice-form- and tissue-specific manner, controlled the storage of memories presumably through actin-capping activity. In support of the C. elegans results, genetic variability of the human ADD1 gene was significantly associated with episodic memory performance in healthy young subjects. Finally, human ADD1 expression in nematodes restored loss of C. elegans add-1 gene function. Taken together, our findings support a role for α-adducin in memory from nematodes to humans. Studying the molecular and genetic underpinnings of memory across distinct species may be helpful in the development of novel strategies to treat memory-related diseases.
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Bar-Lavan Y, Kosolapov L, Frumkin A, Ben-Zvi A. Regulation of cellular protein quality control networks in a multicellular organism. FEBS J 2012; 279:526-31. [PMID: 22177281 DOI: 10.1111/j.1742-4658.2011.08455.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The long-term health of all metazoan cells is linked to protein quality control, which is achieved by proteostasis, a complex network of molecular interactions that determines the health of the proteome under physiological or stress conditions. Studying the regulation of cellular proteostasis in the context of the whole organism has unraveled multiple layers of cell-nonautonomous regulation, including neuronal regulation, cell-to-cell stress signals and endocrine signaling that affect growth, development and aging. Here, we discuss emerging concepts in cell-nonautonomous regulation of protein quality control networks. The identification of organismal modulators of cellular proteostasis may present novel, yet general targets for misfolding disease intervention.
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Affiliation(s)
- Yael Bar-Lavan
- Department of Life Sciences and The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Rezai P, Salam S, Selvaganapathy PR, Gupta BP. Effect of pulse direct current signals on electrotactic movement of nematodes Caenorhabditis elegans and Caenorhabditis briggsae. BIOMICROFLUIDICS 2011; 5:44116-441169. [PMID: 22232698 PMCID: PMC3253587 DOI: 10.1063/1.3665224] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 11/11/2011] [Indexed: 05/22/2023]
Abstract
The nematodes (worms) Caenorhabditiselegans and Caenorhabditisbriggsae are well-known model organisms to study the basis of animal development and behaviour. Their sinusoidal pattern of movement is highly stereotypic and serves as a tool to monitor defects in neurons and muscles that control movement. Until recently, a simple yet robust method to initiate movement response on-demand did not exist. We have found that the electrical stimulation in a microfluidic channel, using constant DC electric field, induces movement (termed electrotaxis) that is instantaneous, precise, sensitive, and fully penetrant. We have further characterized this behaviour and, in this paper, demonstrate that electrotaxis can also be induced using a pulse DC electric signal. Worms responded to pulse DC signals with as low as 30% duty cycle by moving towards the negative electrode at the same speed as constant DC fields (average speed of C. elegans = 296 ± 43 μm/s and C. briggsae = 356 ± 20 μm/s, for both constant and pulse DC electric fields with various frequencies). C. briggsae was found to be more sensitive to electric signals compared to C. elegans. We also investigated the turning response of worms to a change in the direction of constant and pulse DC signals. The response for constant DC signal was found to be instantaneous and similar for most worms. However, in the case of pulse DC signal, alterations in duty cycle affected the turning response time as well as the number of responding worms. Our findings show that pulse DC method allows quantitative measurement of response behaviour of worms and suggest that it could be used as a tool to study the neuronal basis of such a behaviour that is not observed under constant DC conditions.
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Leksomboon R, Chaijaroonkhanarak W, Arunyanart C, Umka J, Jones MK, Sripa B. Organization of the nervous system in Opisthorchis viverrini investigated by histochemical and immunohistochemical study. Parasitol Int 2011; 61:107-11. [PMID: 21807116 DOI: 10.1016/j.parint.2011.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 07/08/2011] [Accepted: 07/10/2011] [Indexed: 11/26/2022]
Abstract
The structure and organization of the nervous system has been documented for various helminth parasites. However, the neuroanatomy of the carcinogenic liver fluke, Opisthorchis viverrini has not been described. This study therefore investigated the organization of the nervous system of this fluke using cholinesterase activity, aminergic and peptidergic (FMRFamide-like peptides) immunostaining to tag major neural elements. The nervous system, as detected by acetylcholinesterase (AchE) reaction, was similar in newly excysted metacercariae, migrating juveniles and adult parasites. In these stages, there were three pairs (dorsal, ventral and lateral) of bilaterally symmetrical longitudinal nerve cords and two cerebral ganglia. The ventral nerve cords and the cerebral ganglia were well-developed and exhibited strong AchE reactivity, as well as aminergic and FMRFamide-like immunoreactivity. Numerous immunoreactive nerve cell bodies were observed around the inner surface of the ventral sucker. Fine FMRFamide-like peptides immunopositive nerve fiber was rarely observed. Overall, the organization of the nervous system of O. viverrini is similar to other trematodes.
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Affiliation(s)
- Ratana Leksomboon
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
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Nishida Y, Sugi T, Nonomura M, Mori I. Identification of the AFD neuron as the site of action of the CREB protein in Caenorhabditis elegans thermotaxis. EMBO Rep 2011; 12:855-62. [PMID: 21738224 PMCID: PMC3147260 DOI: 10.1038/embor.2011.120] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 05/24/2011] [Accepted: 05/24/2011] [Indexed: 11/09/2022] Open
Abstract
Behaviour is a consequence of computation in neural circuits composed of massive synaptic connections among sensory neurons and interneurons. The cyclic AMP response element-binding protein (CREB) responsible for learning and memory is expressed in almost all neurons. Nevertheless, we find that the Caenorhabditis elegans CREB orthologue, CRH-1, is only required in the single bilateral thermosensory neuron AFD, for a memory-related behaviour. Restoration of CRH-1 in AFD of CREB-depleted crh-1 mutants rescues its thermotactic defect, whereas restorations in other neurons do not. In calcium-imaging analyses, the AFD neurons of CREB-depleted crh-1 mutants exhibit an abnormal response to temperature increase. We present a new platform for analysing the mechanism of behavioural memory at single-cellular resolution within the neural circuit.
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Affiliation(s)
- Yukuo Nishida
- Group of Molecular Neurobiology, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Takuma Sugi
- Group of Molecular Neurobiology, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Mayu Nonomura
- Group of Molecular Neurobiology, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Ikue Mori
- Group of Molecular Neurobiology, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
- CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan
- Institute for Advanced Research, Nagoya University, Nagoya 464-8602, Japan
- Tel: +81 52 789 4560; Fax: +81 52 789 4558; E-mail:
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Regulation of behavioral plasticity by systemic temperature signaling in Caenorhabditis elegans. Nat Neurosci 2011; 14:984-92. [DOI: 10.1038/nn.2854] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 05/03/2011] [Indexed: 01/09/2023]
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40
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Behavioral choice between conflicting alternatives is regulated by a receptor guanylyl cyclase, GCY-28, and a receptor tyrosine kinase, SCD-2, in AIA interneurons of Caenorhabditis elegans. J Neurosci 2011; 31:3007-15. [PMID: 21414922 DOI: 10.1523/jneurosci.4691-10.2011] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Animals facing conflicting sensory cues make a behavioral choice between competing alternatives through integration of the sensory cues. Here, we performed a genetic screen to identify genes important for the sensory integration of two conflicting cues, the attractive odorant diacetyl and the aversive stimulus Cu(2+), and found that the membrane-bound guanylyl cyclase GCY-28 and the receptor tyrosine kinase SCD-2 regulate the behavioral choice between these alternatives in Caenorhabditis elegans. The gcy-28 mutants and scd-2 mutants show an abnormal bias in the behavioral choice between the cues, although their responses to each individual cue are similar to those in wild-type animals. Mutants in a gene encoding a cyclic nucleotide gated ion channel, cng-1, also exhibit the defect in sensory integration. Molecular genetic analyses suggested that GCY-28 and SCD-2 regulate sensory integration in AIA interneurons, where the conflicting sensory cues may converge. Genetic ablation or hyperpolarization of AIA interneurons showed nearly the same phenotype as gcy-28 or scd-2 mutants in the sensory integration, although this did not affect the sensory response to each individual cue. In gcy-28 or scd-2 mutants, activation of AIA interneurons is sufficient to restore normal sensory integration. These results suggest that the activity of AIA interneurons regulates the behavioral choice between the alternatives. We propose that GCY-28 and SCD-2 regulate sensory integration by modulating the activity of AIA interneurons.
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Neural coding in a single sensory neuron controlling opposite seeking behaviours in Caenorhabditis elegans. Nat Commun 2011; 2:355. [PMID: 21673676 PMCID: PMC3156818 DOI: 10.1038/ncomms1352] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 05/17/2011] [Indexed: 01/21/2023] Open
Abstract
Unveiling the neural codes for intricate behaviours is a major challenge in neuroscience. The neural circuit for the temperature-seeking behaviour of Caenorhabditis elegans is an ideal system to dissect how neurons encode sensory information for the execution of behavioural output. Here we show that the temperature-sensing neuron AFD transmits both stimulatory and inhibitory neural signals to a single interneuron AIY. In this circuit, a calcium concentration threshold in AFD acts as a switch for opposing neural signals that direct the opposite behaviours. Remote control of AFD activity, using a light-driven ion pump and channel, reveals that diverse reduction levels of AFD activity can generate warm- or cold-seeking behaviour. Calcium imaging shows that AFD uses either stimulatory or inhibitory neuronal signalling onto AIY, depending on the calcium concentration threshold in AFD. Thus, dual neural regulation in opposite directions is directly coupled to behavioural inversion in the simple neural circuit. The neuronal mechanisms responsible for thermal seeking behaviour in Caenorhabditis. elegans are not fully understood. In this study, the sensory neuron AFD is shown to be involved in the responses to both cold and warm temperatures by transmitting inhibitory and excitatory signals to the interneuron AIY.
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Oda S, Tomioka M, Iino Y. Neuronal plasticity regulated by the insulin-like signaling pathway underlies salt chemotaxis learning in Caenorhabditis elegans. J Neurophysiol 2011; 106:301-8. [PMID: 21525368 DOI: 10.1152/jn.01029.2010] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Quantification of neuronal plasticity in a living animal is essential for understanding learning and memory. Caenorhabditis elegans shows a chemotactic behavior toward NaCl. However, it learns to avoid NaCl after prolonged exposure to NaCl under starvation conditions, which is called salt chemotaxis learning. Insulin-like signaling is important for this behavioral plasticity and functions in one of the salt-sensing sensory neurons, ASE right (ASER). However, how neurons including ASER show neuronal plasticity is unknown. To determine the neuronal plasticity related to salt chemotaxis learning, we measured Ca(2+) response and synaptic release of individual neurons by using in vivo imaging techniques. We found that response of ASER increased whereas its synaptic release decreased after prolonged exposure to NaCl without food. These changes in the opposite directions were abolished in insulin-like signaling mutants, suggesting that insulin-like signaling regulates these plasticities in ASER. The response of one of the downstream interneurons, AIB, decreased profoundly after NaCl conditioning. This alteration in AIB response was independent of the insulin-like signaling pathway. Our results suggest that information on NaCl is modulated at the level of both sensory neurons and interneurons in salt chemotaxis learning.
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Affiliation(s)
- Shigekazu Oda
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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43
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Hulme SE, Whitesides GM. Die Chemie und der Wurm: Caenorhabditis elegans als Plattform für das Zusammenführen von chemischer und biologischer Forschung. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201005461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Hulme SE, Whitesides GM. Chemistry and the Worm: Caenorhabditis elegans as a Platform for Integrating Chemical and Biological Research. Angew Chem Int Ed Engl 2011; 50:4774-807. [DOI: 10.1002/anie.201005461] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Indexed: 12/15/2022]
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45
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Liu Y, LeBeouf B, Guo X, Correa PA, Gualberto DG, Lints R, Garcia LR. A cholinergic-regulated circuit coordinates the maintenance and bi-stable states of a sensory-motor behavior during Caenorhabditis elegans male copulation. PLoS Genet 2011; 7:e1001326. [PMID: 21423722 PMCID: PMC3053324 DOI: 10.1371/journal.pgen.1001326] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 02/04/2011] [Indexed: 11/18/2022] Open
Abstract
Penetration of a male copulatory organ into a suitable mate is a conserved and necessary behavioral step for most terrestrial matings; however, the detailed molecular and cellular mechanisms for this distinct social interaction have not been elucidated in any animal. During mating, the Caenorhabditis elegans male cloaca is maintained over the hermaphrodite's vulva as he attempts to insert his copulatory spicules. Rhythmic spicule thrusts cease when insertion is sensed. Circuit components consisting of sensory/motor neurons and sex muscles for these steps have been previously identified, but it was unclear how their outputs are integrated to generate a coordinated behavior pattern. Here, we show that cholinergic signaling between the cloacal sensory/motor neurons and the posterior sex muscles sustains genital contact between the sexes. Simultaneously, via gap junctions, signaling from these muscles is transmitted to the spicule muscles, thus coupling repeated spicule thrusts with vulval contact. To transit from rhythmic to sustained muscle contraction during penetration, the SPC sensory-motor neurons integrate the signal of spicule's position in the vulva with inputs from the hook and cloacal sensilla. The UNC-103 K(+) channel maintains a high excitability threshold in the circuit, so that sustained spicule muscle contraction is not stimulated by fewer inputs. We demonstrate that coordination of sensory inputs and motor outputs used to initiate, maintain, self-monitor, and complete an innate behavior is accomplished via the coupling of a few circuit components.
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Affiliation(s)
- Yishi Liu
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Brigitte LeBeouf
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Howard Hughes Medical Institute, Texas A&M University, College Station, Texas, United States of America
| | - Xiaoyan Guo
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Paola A. Correa
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Daisy G. Gualberto
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Howard Hughes Medical Institute, Texas A&M University, College Station, Texas, United States of America
| | - Robyn Lints
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - L. Rene Garcia
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Howard Hughes Medical Institute, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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46
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Avery L. Caenorhabditis elegans behavioral genetics: where are the knobs? BMC Biol 2010; 8:69. [PMID: 20504291 PMCID: PMC2882361 DOI: 10.1186/1741-7007-8-69] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 05/25/2010] [Indexed: 01/17/2023] Open
Abstract
Thousands of behavioral mutants of Caenorhabditis elegans have been studied. I suggest a set of criteria by which some genes important in the evolution of behavior might be recognized, and identify neuropeptide signaling pathways as candidates.
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Affiliation(s)
- Leon Avery
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA.
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47
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Jurado P, Kodama E, Tanizawa Y, Mori I. Distinct thermal migration behaviors in response to different thermal gradients in Caenorhabditis elegans. GENES BRAIN AND BEHAVIOR 2009; 9:120-7. [PMID: 20002199 DOI: 10.1111/j.1601-183x.2009.00549.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nematode Caenorhabditis elegans exhibits a complex behavior called thermotaxis in response to temperature. This behavior is defined as a form of associative learning, in which temperature pairs with the presence or absence of food. Different interpretations have been drawn from the diverse results obtained by several groups, mainly because of the application of different methodologies for the analysis of thermotaxis. To clarify the discrepancies in behavioral observations and subsequent interpretations by different laboratories, we attempted to systematize several parameters to observe thermotaxis behavior as originally defined by Hedgecock and Russell in 1975. In this study, we show clearly how C. elegans can show a conditioned migration toward colder or warmer areas on a thermal gradient, given certain criteria necessary for the observation of thermotaxis. We thus propose to distinguish thermotaxis from other temperature-related behaviors, such as the warm avoidance response displayed at temperature gradients of 1 degrees C/cm and steeper.
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Affiliation(s)
- P Jurado
- Laboratory of Molecular Neurobiology, Department of Molecular Biology, Graduate School of Science, Nagoya University, CREST-JST, Nagoya 464-8602, Japan
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48
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Abstract
For ectotherms, lifespan is increased at low temperature and decreased at high temperature. A new study in Caenorhabditis elegans shows that thermosensory neurons can counteract the effects of high temperature on lifespan by controlling the activity of a steroid signaling pathway.
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Affiliation(s)
- Ikue Mori
- Laboratory of Molecular Neurobiology, Department of Molecular Biology, Graduate School of Science, Nagoya University and CREST-JST, Nagoya, Japan.
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49
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Prahlad V, Morimoto RI. Integrating the stress response: lessons for neurodegenerative diseases from C. elegans. Trends Cell Biol 2009; 19:52-61. [PMID: 19112021 PMCID: PMC4843516 DOI: 10.1016/j.tcb.2008.11.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 11/26/2008] [Accepted: 11/28/2008] [Indexed: 12/21/2022]
Abstract
All cells possess surveillance and homeostatic mechanisms to adjust protein biogenesis to the demands of growth, differentiation, ageing and environmental stress. However, under certain circumstances, these mechanisms fail to adequately respond to proteotoxic imbalances and result in the accumulation of misfolded proteins. In humans, this can lead to neurodegeneration and other protein conformational diseases. To protect itself, the cell employs highly conserved stress responses and chaperone networks to maintain protein-folding homeostasis (proteostasis). Although the regulation of stress responses, such as the heat-shock response, and of proteostasis have been widely considered to be cell autonomous, recent studies using Caenorhabditis elegans have shown that these processes are regulated by neuronal signaling and endocrine pathways and integrated into other functions of the organism. The hierarchical control of the cellular proteostasis machinery affords insight into the organization of stress regulatory networks in multicellular organisms and offers novel targets for the treatment of human protein conformational diseases.
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Affiliation(s)
- Veena Prahlad
- Department of Biochemistry, Molecular Biology and Cell Biology, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA
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50
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Dittman J. Chapter 2 Worm Watching: Imaging Nervous System Structure and Function in Caenorhabditis elegans. ADVANCES IN GENETICS 2009; 65:39-78. [DOI: 10.1016/s0065-2660(09)65002-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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