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Chen Q, Li S, Wang Y, Jia D, Wang Y, Ma R. Morphological Characterstics of the Sensilla in a Monophagous Insect: Agasicles hygrophila Selman and Vogt (Coleoptera: Chrysomelidae, Halticinae). INSECTS 2023; 14:501. [PMID: 37367317 DOI: 10.3390/insects14060501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/27/2023] [Accepted: 05/28/2023] [Indexed: 06/28/2023]
Abstract
Agasicles hygrophila Selman and Vogt (Coleoptera: Chrysomelidae) is the key natural enemy of Alternanthera philoxeroides (Mart.) Griseb, an invasive weed worldwide. To understand the morphology of A. hygrophila and further explore the specific host localization mechanism, scanning electron microscopy was used to observe and study the morphological characteristics of sensilla on the head appendages, tarsi, and external genital segments of A. hygrophila. Twelve types and forty-six subtypes of sensilla were observed. These contain various types of head appendices, including sensilla chaetica, sensilla trichodea, sensilla basiconca, sensilla coeloconica, sensilla styloconica, Böhm bristles, sensilla campaniform, sensilla terminal, sensilla dome, sensilla digit-like, sensilla aperture, and many subtypes. A new type of sensor was reported for the first time, which may be related to host plant recognition. This sensor was located on the distal segment of the maxillary palps of A. hygrophila and was named as sensilla petal-shaped based on its morphological characteristics. Sensilla chaetica, sensilla trichodea, and sensilla basiconca are also found on the tarsi and external genital segments. In addition, sensilla basiconica 4, sensilla coeloconica 1 and 2, sensilla styloconica 2, Böhm bristles 2, and sensilla campaniform 1 were only found in females. On the contrary, sensilla styloconica 3, sensilla coeloconica 3, and sensilla dome were only found in males. Numbers and sizes of the sensilla were also different between males and females. The potential functions related to structure were discussed in comparison with previous investigations on beetles and other monophagous insects. Our results provide a microscopic morphological basis for further research on the localization and recognition mechanism of A. hygrophila and its obligate host.
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Affiliation(s)
- Qianhui Chen
- College of Plant Protection, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Shuang Li
- Chongqing Academy of Agricultural Science, Jiulongpo District, Chongqing 401329, China
| | - Yingying Wang
- College of Plant Protection, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Dong Jia
- College of Plant Protection, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Yuanxin Wang
- College of Plant Protection, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Ruiyan Ma
- College of Plant Protection, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
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Ng R, Wu ST, Su CY. Neuronal Compartmentalization: A Means to Integrate Sensory Input at the Earliest Stage of Information Processing? Bioessays 2020; 42:e2000026. [PMID: 32613656 PMCID: PMC7864560 DOI: 10.1002/bies.202000026] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/20/2020] [Indexed: 01/08/2023]
Abstract
In numerous peripheral sense organs, external stimuli are detected by primary sensory neurons compartmentalized within specialized structures composed of cuticular or epithelial tissue. Beyond reflecting developmental constraints, such compartmentalization also provides opportunities for grouped neurons to functionally interact. Here, the authors review and illustrate the prevalence of these structural units, describe characteristics of compartmentalized neurons, and consider possible interactions between these cells. This article discusses instances of neuronal crosstalk, examples of which are observed in the vertebrate tastebuds and multiple types of arthropod chemosensory hairs. Particular attention is paid to insect olfaction, which presents especially well-characterized mechanisms of functional, cross-neuronal interactions. These examples highlight the potential impact of peripheral processing, which likely contributes more to signal integration than previously considered. In surveying a wide variety of structural units, it is hoped that this article will stimulate future research that determines whether grouped neurons in other sensory systems can also communicate to impact information processing.
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Affiliation(s)
| | | | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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3
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Li DZ, Huang XF, Yang RN, Chen JY, Wang MQ. Functional Analysis of Two Odorant-Binding Proteins, MaltOBP9 and MaltOBP10, in Monochamus alternatus Hope. Front Physiol 2020; 11:317. [PMID: 32351402 PMCID: PMC7174603 DOI: 10.3389/fphys.2020.00317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/20/2020] [Indexed: 11/13/2022] Open
Abstract
Odorant-binding proteins (OBPs) are important for the perception of chemical signals by insects. Effective pest management strategies can be developed by understanding the host location mechanism and the physiological functions of OBPs in olfactory detection. In this study, we cloned two OBPs from Monochamus alternatus, where MaltOBP9 was highly expressed in multiple insect tissues and MaltOBP10 was highly expressed in the female antenna according to the results of qRT-PCR. The recombinant proteins were successfully purified in vitro. Immunocytochemistry indicated the high expression of MaltOBP9 and MaltOBP10 in the sensillum lymph of sensilla basiconica, sensilla trichodea, sensilla auricillica, and sensilla chaetica, thereby demonstrating their broad participation in semiochemical detection. Both proteins were localized in the inner cavity of mechanoreceptors and they exhibited broad binding abilities with volatiles from pine bark according to fluorescence competitive binding assays. Due to its broad binding ability and distribution, MaltOBP9 may be involved in various physiological processes as well as olfactory detection. MaltOBP10 appears to play a role in the fundamental olfactory recognition process of female adults according to its broad binding ability. These findings suggest that OBPs may have various physiological functions in insects, thereby providing novel insights into the olfactory receptive mechanism.
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Affiliation(s)
- Dong-Zhen Li
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiao-Feng Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Rui-Nan Yang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | | | - Man-Qun Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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Merivee E, Must A, Nurme K, Di Giulio A, Muzzi M, Williams I, Mänd M. Neural Code for Ambient Heat Detection in Elaterid Beetles. Front Behav Neurosci 2020; 14:1. [PMID: 32116586 PMCID: PMC7016213 DOI: 10.3389/fnbeh.2020.00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/03/2020] [Indexed: 11/13/2022] Open
Abstract
Environmental thermal conditions play a major role at all levels of biological organization; however, there is little information on noxious high temperature sensation crucial in behavioral thermoregulation and survival of small ectothermic animals such as insects. So far, a capability to unambiguously encode heat has been demonstrated only for the sensory triad of the spike bursting thermo- and two bimodal hygro-thermoreceptor neurons located in the antennal dome-shaped sensilla (DSS) in a carabid beetle. We used extracellular single sensillum recording in the range of 20-45°C to demonstrate that a similar sensory triad in the elaterid Agriotes obscurus also produces high temperature-induced bursty spike trains. Several parameters of the bursts are temperature dependent, allowing the neurons in a certain order to encode different, but partly overlapping ranges of heat up to lethal levels in a graded manner. ISI in a burst is the most useful parameter out of six. Our findings consider spike bursting as a general, fundamental quality of the classical sensory triad of antennal thermo- and hygro-thermoreceptor neurons widespread in many insect groups, being a flexible and reliable mode of coding unfavorably high temperatures. The possible involvement of spike bursting in behavioral thermoregulation of the beetles is discussed. By contrast, the mean firing rate of the neurons in regular and bursty spike trains combined does not carry useful thermal information at the high end of noxious heat.
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Affiliation(s)
- Enno Merivee
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Anne Must
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Karin Nurme
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | | | - Maurizio Muzzi
- Department of Science, University of Roma Tre, Rome, Italy
| | - Ingrid Williams
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Marika Mänd
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
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Nurme K, Must A, Merivee E. Link between elevated locomotor activity and the spike bursting of antennal thermosensitive neurons in the carabid beetle Pterostichus oblongopunctatus. ACTA ZOOL ACAD SCI H 2019. [DOI: 10.17109/azh.65.suppl.21.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Nurme K, Merivee E, Must A, Di Giulio A, Muzzi M, Williams I, Mänd M. Bursty spike trains of antennal thermo- and bimodal hygro-thermoreceptor neurons encode noxious heat in elaterid beetles. J Therm Biol 2018; 72:101-117. [PMID: 29496003 DOI: 10.1016/j.jtherbio.2018.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 11/16/2022]
Abstract
The main purpose of this study was to explain the internal fine structure of potential antennal thermo- and hygroreceptive sensilla, their innervation specifics, and responses of the sensory neurons to thermal and humidity stimuli in an elaterid beetle using focused ion beam scanning electron microscopy and electrophysiology, respectively. Several essential, high temperature induced turning points in the locomotion were determined using automated video tracking. Our results showed that the sensilla under study, morphologically, are identical to the dome-shaped sensilla (DSS) of carabids. A cold-hot neuron and two bimodal hygro-thermoreceptor neurons, the moist-hot and dry-hot neuron, innervate them. Above 25-30 °C, all the three neurons, at different threshold temperatures, switch from regular spiking to temperature dependent spike bursting. The percentage of bursty DSS neurons on the antenna increases with temperature increase suggesting that this parameter of the neurons may encode noxious heat in a graded manner. Thus, we show that besides carabid beetles, elaterids are another large group of insects with this ability. The threshold temperature of the beetles for onset of elevated locomotor activity (OELA) was lower by 11.9 °C compared to that of critical thermal maximum (39.4 °C). Total paralysis occurred at 41.8 °C. The threshold temperatures for spike bursting of the sensory neurons in DSS and OELA of the beetles coincide suggesting that probably the spike bursts are responsible for encoding noxious heat when confronted. In behavioural thermoregulation, spike bursting DSS neurons serve as a fast and firm three-fold early warning system for the beetles to avoid overheating and death.
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Affiliation(s)
- Karin Nurme
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
| | - Enno Merivee
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Anne Must
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Andrea Di Giulio
- Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy
| | - Maurizio Muzzi
- Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy
| | - Ingrid Williams
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Marika Mänd
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
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7
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Encoding noxious heat by spike bursts of antennal bimodal hygroreceptor (dry) neurons in the carabid Pterostichus oblongopunctatus. Cell Tissue Res 2016; 368:29-46. [DOI: 10.1007/s00441-016-2547-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
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8
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Zauli A, Maurizi E, Carpaneto GM, Chiari S, Merivee E, Svensson GP, Di Giulio A. Scanning electron microscopy analysis of the antennal sensilla in the rare saproxylic beetle Elater ferrugineus (Coleoptera: Elateridae). ACTA ACUST UNITED AC 2016. [DOI: 10.1080/11250003.2016.1211766] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- A. Zauli
- Department of Science, Roma Tre University, Rome, Italy
| | - E. Maurizi
- Department of Science, Roma Tre University, Rome, Italy
- Centro di Ricerca per l’Agrobiologia e la Pedologia, Consiglio per la Ricerca in agricoltura e l’analisi dell’economia agraria (CREA-ABP), Firenze, Italy
- Corpo Forestale dello Stato, Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale “Bosco Fontana” di Verona (CNBFVR), Marmirolo, Italy
| | | | - S. Chiari
- Department of Science, Roma Tre University, Rome, Italy
- Centro di Ricerca per l’Agrobiologia e la Pedologia, Consiglio per la Ricerca in agricoltura e l’analisi dell’economia agraria (CREA-ABP), Firenze, Italy
- Corpo Forestale dello Stato, Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale “Bosco Fontana” di Verona (CNBFVR), Marmirolo, Italy
| | - E. Merivee
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | | | - A. Di Giulio
- Department of Science, Roma Tre University, Rome, Italy
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Merivee E, Tooming E, Must A, Sibul I, Williams IH. Low doses of the common alpha-cypermethrin insecticide affect behavioural thermoregulation of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 120:286-294. [PMID: 26094034 DOI: 10.1016/j.ecoenv.2015.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 06/05/2015] [Accepted: 06/09/2015] [Indexed: 06/04/2023]
Abstract
Sub-lethal effects of pesticides on behavioural endpoints are poorly investigated in non-targeted beneficial carabids. Conspicuous changes in locomotor activity of carabids exposed to sub-lethal doses of neurotoxic insecticides suggest that many other behaviours of these insects might be severely injured as well. We hypothesize that behavioural thermoregulation of carabids may be affected by low doses of neurotoxic pyrethroid insecticide alpha-cypermethrin which may have direct deleterious consequences for the fitness and populations of the beetles in the field. Automated video tracking of the carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) on an experimental thermal mosaic arena using EthoVision XT Version 9 software (Noldus Information Technology, Wageningen, The Netherlands) showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations (0.1-10mgL(-1)) drastically reduces the ability of the beetles for behavioural thermoregulation. At noxious high temperature, a considerable number of the beetles died due to thermo-shock. Other intoxicated beetles that survived exposure to high temperature displayed behavioural abnormalities. During heating of the arena from 25 to 45°C, insecticide treated beetles showed a significant fall in tendency to hide in a cool shelter (20°C) and prolonged exposure to noxious high temperatures, accompanied by changes in locomotor activity. Next day after insecticide treatment the beetles recovered from behavioural abnormalities to a large extent but they still were considerably longer exposed to noxious high temperatures compared to the negative control beetles. Our results demonstrated that behavioural thermoregulation is a sensitive and important etho-toxicological biomarker in ground-dwelling carabids. Prolonged exposure to unfavourably high temperatures has an array of negative effects decreasing fitness and survival of these insects at elevated thermal conditions with deep temperature gradients, typical of agricultural habitats. These results may have importance in IPM programs promoting reduced insecticide use.
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Affiliation(s)
- Enno Merivee
- Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 1 Kreutzwaldi Street, 51014 Tartu, Estonia.
| | - Ene Tooming
- Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 1 Kreutzwaldi Street, 51014 Tartu, Estonia
| | - Anne Must
- Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 1 Kreutzwaldi Street, 51014 Tartu, Estonia
| | - Ivar Sibul
- Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, 1 Kreutzwaldi Street, 51014 Tartu, Estonia
| | - Ingrid H Williams
- Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 1 Kreutzwaldi Street, 51014 Tartu, Estonia
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10
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Nurme K, Merivee E, Must A, Sibul I, Muzzi M, Di Giulio A, Williams I, Tooming E. Responses of the antennal bimodal hygroreceptor neurons to innocuous and noxious high temperatures in the carabid beetle, Pterostichus oblongopunctatus. JOURNAL OF INSECT PHYSIOLOGY 2015; 81:1-13. [PMID: 26099925 DOI: 10.1016/j.jinsphys.2015.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 06/04/2023]
Abstract
Electrophysiological responses of thermo- and hygroreceptor neurons from antennal dome-shaped sensilla of the carabid beetle Pterostichus oblongopunctatus to different levels of steady temperature ranging from 20 to 35°C and rapid step-changes in it were measured and analysed at both constant relative and absolute ambient air humidity conditions. It appeared that both hygroreceptor neurons respond to temperature which means that they are bimodal. For the first time in arthropods, the ability of antennal dry and moist neurons to produce high temperature induced spike bursts is documented. Burstiness of the spike trains is temperature dependent and increases with temperature increase. Threshold temperatures at which the two neurons switch from regular spiking to spike bursting are lower compared to that of the cold neuron, differ and approximately coincide with the upper limit of preferred temperatures of the species. We emphasise that, in contrast to various sensory systems studied, the hygroreceptor neurons of P. oblongopunctatus have stable and continuous burst trains, no temporal information is encoded in the timing of the bursts. We hypothesise that temperature dependent spike bursts produced by the antennal thermo- and hygroreceptor neurons may be responsible for detection of noxious high temperatures important in behavioural thermoregulation of carabid beetles.
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Affiliation(s)
- Karin Nurme
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
| | - Enno Merivee
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Anne Must
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Ivar Sibul
- Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Maurizio Muzzi
- Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy
| | - Andrea Di Giulio
- Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy
| | - Ingrid Williams
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
| | - Ene Tooming
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia
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11
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Wang D, O'Halloran D, Goodman MB. GCY-8, PDE-2, and NCS-1 are critical elements of the cGMP-dependent thermotransduction cascade in the AFD neurons responsible for C. elegans thermotaxis. ACTA ACUST UNITED AC 2014; 142:437-49. [PMID: 24081984 PMCID: PMC3787776 DOI: 10.1085/jgp.201310959] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Certain thermoreceptor neurons are sensitive to tiny thermal fluctuations (0.01°C or less) and maintain their sensitivity across a wide range of ambient temperatures through a process of adaptation, but understanding of the biochemical basis for this performance is rudimentary. Prior studies of the AFD thermoreceptor in Caenorhabditis elegans revealed a signaling cascade that depends on a trio of receptor guanylate cyclases (rGCs), GCY-8, GCY-18, and GCY-23, and gives rise to warming-activated thermoreceptor currents (ThRCs) carried by cyclic GMP–gated ion channels. The threshold for ThRC activation adapts to the ambient temperature through an unknown calcium-dependent process. Here, we use in vivo whole-cell patch-clamp recording from AFD to show that loss of GCY-8, but not of GCY-18 or GCY-23, reduces or eliminates ThRCs, identifying this rGC as a crucial signaling element. To learn more about thermotransduction and adaptation, we used behavioral screens and analysis of gene expression patterns to identify phosphodiesterases (PDEs) likely to contribute to thermotransduction. Deleting PDE-2 decouples the threshold for ThRC activation from ambient temperature, altering adaptation. We provide evidence that the conserved neuronal calcium sensor 1 protein also regulates the threshold for ThRC activation and propose a signaling network to account for ThRC activation and adaptation. Because PDEs play essential roles in diverse biological processes, including vertebrate phototransduction and olfaction, and regulation of smooth muscle contractility and cardiovascular function, this study has broad implications for understanding how extraordinary sensitivity and dynamic range is achieved in cyclic nucleotide–based signaling networks.
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Affiliation(s)
- Dong Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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12
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Marsat G, Pollack GS. Bursting neurons and ultrasound avoidance in crickets. Front Neurosci 2012; 6:95. [PMID: 22783158 PMCID: PMC3387578 DOI: 10.3389/fnins.2012.00095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/11/2012] [Indexed: 11/13/2022] Open
Abstract
Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes - bursts - that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing - the auditory receptor - already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2's sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.
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Affiliation(s)
- Gary Marsat
- Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
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Di Giulio A, Maurizi E, Rossi Stacconi MV, Romani R. Functional structure of antennal sensilla in the myrmecophilous beetle Paussus favieri (Coleoptera, Carabidae, Paussini). Micron 2012; 43:705-19. [DOI: 10.1016/j.micron.2011.10.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 11/30/2022]
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Piersanti S, Rebora M, Almaas TJ, Salerno G, Gaino E. Electrophysiological identification of thermo- and hygro-sensitive receptor neurons on the antennae of the dragonfly Libellula depressa. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:1391-1398. [PMID: 21801729 DOI: 10.1016/j.jinsphys.2011.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 07/06/2011] [Accepted: 07/06/2011] [Indexed: 05/31/2023]
Abstract
Recent ultrastructural investigations on Odonata antennal flagellum describe two types of sensilla styloconica, T1 and T2. The styloconic sensilla are located in pits, at the bottom of deep cavities, and share common features typical of thermo-hygroreceptors. In order to ascertain if the Odonata antennae are involved in hygroreception and thermoreception, we carried out electrophysiological recordings (single cell recordings, SCR) from adult males and females of Libellula depressa L., 1758. After contact was established, the antenna was stimulated by rapid changes in temperature and humidity. The present research shows the occurrence of a dry (DC), a moist (MC) and a cold (CC) receptor neurons on the antennal flagellum of L. depressa. These data demonstrate for the first time the presence of functional thermo-hygroreceptors on the antennal flagellum of dragonflies. The present results extend our knowledge of the not visual sensory modalities of Odonata, a field of research unexplored so far.
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Affiliation(s)
- Silvana Piersanti
- Dipartimento di Biologia Cellulare e Ambientale, Via Elce di Sotto 1, Perugia, Italy.
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15
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Coggan N, Clissold FJ, Simpson SJ. Locusts use dynamic thermoregulatory behaviour to optimize nutritional outcomes. Proc Biol Sci 2011; 278:2745-52. [PMID: 21288941 DOI: 10.1098/rspb.2010.2675] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to optimize performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria, we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences.
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Affiliation(s)
- Nicole Coggan
- School of Biological Sciences, The University of Sydney, New South Wales 2006, Australia
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Merivee E, Must A, Luik A, Williams I. Electrophysiological identification of hygroreceptor neurons from the antennal dome-shaped sensilla in the ground beetle Pterostichus oblongopunctatus. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1671-1678. [PMID: 20615410 DOI: 10.1016/j.jinsphys.2010.06.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/29/2010] [Accepted: 06/29/2010] [Indexed: 05/29/2023]
Abstract
This study gives the first electrophysiological evidence of hygroreceptors in carabids. Extracellular recordings from the antennal dome-shaped sensilla of the carabid beetle Pterostichus oblolongopunctatus (Coleoptera, Carabidae) clearly show the presence of moist and dry neuron antagonistically responding to humidity changes. The cold neuron of the same sensillum did not respond to changes in humidity. For the first time, we demonstrate that the binary system of two antagonistic hygroreceptor neurons discriminates differences between steady-state humidity levels more sensitively than either neuron separately. Another advantage of the binary system is that it guarantees immediate and strong phasic-tonic response to rapid humidity changes in either direction. In the hygrosensing system of carabids, this would allow detection of subtle step-changes in humidity with greater sensitivity than differences in steady-state values of humidity. Thus, construction of the hygrosensing system with opposing receptor neurons may allow insects to detect environmental humidity differences critical for their habitat and microhabitat selection, and survival with great precision.
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Affiliation(s)
- Enno Merivee
- Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, Tartu, Estonia.
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