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Abbas F, Vinberg F. Transduction and Adaptation Mechanisms in the Cilium or Microvilli of Photoreceptors and Olfactory Receptors From Insects to Humans. Front Cell Neurosci 2021; 15:662453. [PMID: 33867944 PMCID: PMC8046925 DOI: 10.3389/fncel.2021.662453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/02/2021] [Indexed: 12/11/2022] Open
Abstract
Sensing changes in the environment is crucial for survival. Animals from invertebrates to vertebrates use both visual and olfactory stimuli to direct survival behaviors including identification of food sources, finding mates, and predator avoidance. In primary sensory neurons there are signal transduction mechanisms that convert chemical or light signals into an electrical response through ligand binding or photoactivation of a receptor, that can be propagated to the olfactory and visual centers of the brain to create a perception of the odor and visual landscapes surrounding us. The fundamental principles of olfactory and phototransduction pathways within vertebrates are somewhat analogous. Signal transduction in both systems takes place in the ciliary sub-compartments of the sensory cells and relies upon the activation of G protein-coupled receptors (GPCRs) to close cyclic nucleotide-gated (CNG) cation channels in photoreceptors to produce a hyperpolarization of the cell, or in olfactory sensory neurons open CNG channels to produce a depolarization. However, while invertebrate phototransduction also involves GPCRs, invertebrate photoreceptors can be either ciliary and/or microvillar with hyperpolarizing and depolarizing responses to light, respectively. Moreover, olfactory transduction in invertebrates may be a mixture of metabotropic G protein and ionotropic signaling pathways. This review will highlight differences of the visual and olfactory transduction mechanisms between vertebrates and invertebrates, focusing on the implications to the gain of the transduction processes, and how they are modulated to allow detection of small changes in odor concentration and light intensity over a wide range of background stimulus levels.
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Affiliation(s)
- Fatima Abbas
- Vinberg Lab, Department of Ophthalmology and Visual Science, John A. Moran Center, University of Utah, Salt Lake City, UT, United States
| | - Frans Vinberg
- Vinberg Lab, Department of Ophthalmology and Visual Science, John A. Moran Center, University of Utah, Salt Lake City, UT, United States
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Acid-Sensing Ion Channels Contribute to Type III Adenylyl Cyclase-Independent Acid Sensing of Mouse Olfactory Sensory Neurons. Mol Neurobiol 2020; 57:3042-3056. [PMID: 32458389 DOI: 10.1007/s12035-020-01943-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 05/13/2020] [Indexed: 10/24/2022]
Abstract
Acids can disturb the ecosystem of wild animals through altering their olfaction and olfaction-related survival behaviors. It is known that the main olfactory epithelia (MOE) of mammals rely on odorant receptors and type III adenylyl cyclase (AC3) to detect general odorants. However, it is unknown how the olfactory system sense protons or acidic odorants. Here, we show that while the MOE of AC3 knockout (KO) mice failed to respond to an odor mix in electro-olfactogram (EOG) recordings, it retained a small fraction of acid-evoked EOG responses. The acetic acid-induced EOG responses in wild-type (WT) MOE can be dissected into two components: the big component dependent on the AC3-mediated cAMP pathway and the much smaller component not. The small acid-evoked EOG response of the AC3 KOs was blocked by diminazene, an inhibitor of acid-sensing ion channels (ASICs), but not by forskolin/IBMX that desensitize the cAMP pathway. AC3 KO mice lost their sensitivity to detect pungent odorants but maintained sniffing behavior to acetic acid. Immunofluorescence staining demonstrated that ASIC1 proteins were highly expressed in olfactory sensory neurons (OSNs), mostly enriched in the knobs, dendrites, and somata, but not in olfactory cilia. Real-time polymerase chain reaction further detected the mRNA expression of ASIC1a, ASIC2b, and ASIC3 in the MOE. Additionally, mice exhibited reduced preference to attractive objects when placed in an environment with acidic volatiles. Together, we conclude that the mouse olfactory system has a non-conventional, likely ASIC-mediated ionotropic mechanism for acid sensing.
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Liu S, Fu R, Li G. Exploring the mechanism of olfactory recognition in the initial stage by modeling the emission spectrum of electron transfer. PLoS One 2020; 15:e0217665. [PMID: 31923248 PMCID: PMC6953861 DOI: 10.1371/journal.pone.0217665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/29/2019] [Indexed: 11/19/2022] Open
Abstract
Olfactory sense remains elusive regarding the primary reception mechanism. Some studies suggest that olfaction is a spectral sense, the olfactory event is triggered by electron transfer (ET) across the odorants at the active sites of odorant receptors (ORs). Herein we present a Donor-Bridge-Acceptor model, proposing that the ET process can be viewed as an electron hopping from the donor molecule to the odorant molecule (Bridge), then hopping off to the acceptor molecule, making the electronic state of the odorant molecule change along with vibrations (vibronic transition). The odorant specific parameter, Huang–Rhys factor can be derived from ab initio calculations, which make the simulation of ET spectra achievable. In this study, we revealed that the emission spectra (after Gaussian convolution) can be acted as odor characteristic spectra. Using the emission spectrum of ET, we were able to reasonably interpret the similar bitter-almond odors among hydrogen cyanide, benzaldehyde and nitrobenzene. In terms of isotope effects, we succeeded in explaining why subjects can easily distinguish cyclopentadecanone from its fully deuterated analogue cyclopentadecanone-d28 but not distinguishing acetophenone from acetophenone-d8.
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Affiliation(s)
- Shu Liu
- Department of Anatomy, Anhui Medical University, Hefei, Anhui, China
- * E-mail:
| | - Rao Fu
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guangwu Li
- Department of Anatomy, Anhui Medical University, Hefei, Anhui, China
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PIM-Related Kinases Selectively Regulate Olfactory Sensations in Caenorhabditis elegans. eNeuro 2019; 6:ENEURO.0003-19.2019. [PMID: 31387876 PMCID: PMC6709224 DOI: 10.1523/eneuro.0003-19.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 07/12/2019] [Accepted: 07/18/2019] [Indexed: 11/21/2022] Open
Abstract
The mammalian PIM family of serine/threonine kinases regulate several cellular functions, such as cell survival and motility. Because PIM expression is observed in sensory organs, such as olfactory epithelium, we now wanted to explore the physiological roles of PIM kinases there. As our model organism, we used the Caenorhabditis elegans nematodes, which express two PIM-related kinases, PRK-1 and PRK-2. We demonstrated PRKs to be true PIM orthologs with similar substrate specificity as well as sensitivity to PIM-inhibitory compounds. When we analyzed the effects of pan-PIM inhibitors on C. elegans sensory functions, we observed that PRK activity is selectively required to support olfactory sensations to volatile repellents and attractants sensed by AWB and AWCON neurons, respectively, but is dispensable for gustatory sensations. Analyses of prk-deficient mutant strains confirmed these findings and suggested that PRK-1, but not PRK-2 is responsible for the observed effects on olfaction. This regulatory role of PRK-1 is further supported by its observed expression in the head and tail neurons, including AWB and AWC neurons. Based on the evolutionary conservation of PIM-related kinases, our data may have implications in regulation of also mammalian olfaction.
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Molecular evidence for the inhibition of cytochrome p450s and cholinesterases in ticks by the repellent DEET. Ticks Tick Borne Dis 2019; 10:515-522. [PMID: 30612950 DOI: 10.1016/j.ttbdis.2018.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/18/2018] [Accepted: 12/23/2018] [Indexed: 10/27/2022]
Abstract
For more than 50 years DEET (N,N-Diethyl-m-toluamide) has been considered the gold standard of repellents. It is applied to the skin or clothing to deter mosquitoes and other blood-sucking invertebrate pests from approaching and/or settling, and ultimately it provides temporary protection from bites. Despite rampant global use, surprisingly little is understood about DEET's mode of action and the molecular targets of the active ingredient. Furthermore, the theories into its mechanism for repellency are largely based off fruit fly and mosquito research. Since ticks possess a unique sensory structure, the Haller's organ, the specific genes and pathways associated with DEET avoidance may differ from insects. In these studies, we collected American dog ticks (Dermacentor variabilis) from four natural populations within Manitoba, Canada. We first carried out behavior assays, which showed DEET effectively repelled the ticks. RNA sequencing revealed that DEET caused a rapid and substantial reduction in the abundance of transcripts encoding cytochrome P450 and acetylcholinesterase genes, which gradually recovered over the 24 h time course. Finally, enzymatic kinetics provided functional support for DEET's role as an effective inhibitor of P450 s. While many facets of its mode of action remain to be worked out, our study provides valuable insights into the molecular underpinnings of DEET's repellence in ticks.
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Soffan A, Subandiyah S, Makino H, Watanabe T, Horiike T. Evolutionary Analysis of the Highly Conserved Insect Odorant Coreceptor (Orco) Revealed a Positive Selection Mode, Implying Functional Flexibility. JOURNAL OF INSECT SCIENCE (ONLINE) 2018; 18:5236977. [PMID: 30535416 PMCID: PMC6287053 DOI: 10.1093/jisesa/iey120] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Indexed: 06/09/2023]
Abstract
Odorant coreceptor (Orco) represents one of the essential genes in the insect olfactory system, which facilitates signal transduction and heterodimerization with different odorant receptors (Ors) in the insect antennal dendritic membrane. Evolutionary analysis by detecting positive selection is important to examine the functional flexibility of Orco that potentially supports insect survival. The maximum likelihood codon substitution model was applied using CODEML program as implemented in PAML ver 4.9e package across 59 Orco codon sequences available from GenBank. These sequences represented five major insect orders and two reproductive systems (holometabola and nonholometabola). In the site model that identified common ω values for Orco, it was clearly shown that Orco was under strong purifying selection, indicated by the ω value that was far from 1 (ω: 0.03). However, in to the branch model, positive selection was detected to be acting on Dipteran lineages, whereas in the branch-site model, several sites were under significant positive selection occurring in the following four clades: Coleoptera, Diptera, Lepidoptera, and Psocodea. The typical evolutionary mode acting on Orco was consistent with the entropy value [H(x)], confirming that 48.9% of the Orco site was under conservation (H(x) < 0.5), whereas 26.9% of the Orco sites was under high variation (H(x) > 1). These findings confirmed that Orco genes are generally highly conserved and can possibly be used for the manipulation of insect pest control programs. However, positive selection that acts on certain lineages suggested future adaptive evolutionary ability of Orco to anticipate flexible functions for successful olfactory processes.
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Affiliation(s)
- Alan Soffan
- Department of Plant Protection, Faculty of Agriculture, UniversitasGadjahMada, Yogyakarta, Indonesia
- Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Siti Subandiyah
- Department of Plant Protection, Faculty of Agriculture, UniversitasGadjahMada, Yogyakarta, Indonesia
- Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Hirokazu Makino
- Molecular evolution and Bioinformatics Laboratory, Graduate School of Integrated Science and Technology, Shizuoka University, Japan
| | - Tomoaki Watanabe
- Molecular evolution and Bioinformatics Laboratory, Department of Biological and Environmental Science, Shizuoka University, Japan
| | - Tokumasa Horiike
- Molecular evolution and Bioinformatics Laboratory, Department of Biological and Environmental Science, Shizuoka University, Japan
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Chaiphongpachara T, Bunyuen P, Khlaeo Chansukh K. Development of a More Effective Mosquito Trapping Box for Vector Control. ScientificWorldJournal 2018; 2018:6241703. [PMID: 30154682 PMCID: PMC6093027 DOI: 10.1155/2018/6241703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/13/2018] [Accepted: 07/03/2018] [Indexed: 12/24/2022] Open
Abstract
Mosquito-borne diseases are a major public health issue in nearly all tropical and subtropical countries, making vector control imperative. The mosquito trapping box is one type of mosquito traps that is popular in some areas because it is affordable, environmentally friendly, and easy to produce. This research investigated whether the effectiveness of the mosquito trapping box could be increased through the addition of various physical factors, including a wooden frame, black cotton cloth, a fan, carbon dioxide (CO2), and heat, by testing a range of box designs in the Samut Songkhram Province, Thailand, between December 2016 and January 2017. We found that trapping boxes constructed with Pinus kesiya wood caught more mosquitoes than those constructed with two other types of wood or aluminum. We also found that mosquito trapping boxes were more effective when more factors were added, although these differences were only significant for black cotton cloth and CO2. These findings will guide the future development of mosquito trapping boxes for effective mosquito control in other areas, helping to reduce the incidence of mosquito-borne diseases.
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Affiliation(s)
| | - Ploypailin Bunyuen
- Bachelor of Public Health, College of Allied Health Sciences, Suan Sunandha Rajabhat University, Thailand
| | - Kitthisak Khlaeo Chansukh
- Department of Applied Thai Traditional Medicine, College of Allied Health Sciences, Suan Sunandha Rajabhat University, Thailand
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Experimental evaluation of the generalized vibrational theory of G protein-coupled receptor activation. Proc Natl Acad Sci U S A 2017; 114:5595-5600. [PMID: 28500275 DOI: 10.1073/pnas.1618422114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Recently, an alternative theory concerning the method by which olfactory proteins are activated has garnered attention. This theory proposes that the activation of olfactory G protein-coupled receptors occurs by an inelastic electron tunneling mechanism that is mediated through the presence of an agonist with an appropriate vibrational state to accept the inelastic portion of the tunneling electron's energy. In a recent series of papers, some suggestive theoretical evidence has been offered that this theory may be applied to nonolfactory G protein-coupled receptors (GPCRs), including those associated with the central nervous system (CNS). [Chee HK, June OS (2013) Genomics Inform 11(4):282-288; Chee HK, et al. (2015) FEBS Lett 589(4):548-552; Oh SJ (2012) Genomics Inform 10(2):128-132]. Herein, we test the viability of this idea, both by receptor affinity and receptor activation measured by calcium flux. This test was performed using a pair of well-characterized agonists for members of the 5-HT2 class of serotonin receptors, 2,5-dimethoxy-4-iodoamphetamine (DOI) and N,N-dimethyllysergamide (DAM-57), and their respective deuterated isotopologues. No evidence was found that selective deuteration affected either the binding affinity or the activation by the selected ligands for the examined members of the 5-HT2 receptor class.
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Soffan A, Antony B, Abdelazim M, Shukla P, Witjaksono W, Aldosari SA, Aldawood AS. Silencing the Olfactory Co-Receptor RferOrco Reduces the Response to Pheromones in the Red Palm Weevil, Rhynchophorus ferrugineus. PLoS One 2016; 11:e0162203. [PMID: 27606688 PMCID: PMC5015987 DOI: 10.1371/journal.pone.0162203] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/18/2016] [Indexed: 01/01/2023] Open
Abstract
The red palm weevil (RPW, Rhynchophorus ferrugineus), one of the most widespread of all invasive insect pest species, is a major cause of severe damage to economically important palm trees. RPW exhibits behaviors very similar to those of its sympatric species, the Asian palm weevil (R. vulneratus), which is restricted geographically to the southern part of Southeast Asia. Although efficient and sustainable control of these pests remains challenging, olfactory-system disruption has been proposed as a promising approach for controlling palm weevils. Here, we report the cloning and sequencing of an olfactory co-receptor (Orco) from R. ferrugineus (RferOrco) and R. vulneratus (RvulOrco) and examine the effects of RferOrco silencing (RNAi) on odorant detection. RferOrco and RvulOrco encoding 482 amino acids showing 99.58% identity. The injection of double-stranded RNA (dsRNA) from RferOrco into R. ferrugineus pupae significantly reduced RferOrco gene expression and led to the failure of odor-stimulus detection, as confirmed through olfactometer and electroantennography (EAG) assays. These results suggest that olfactory-system disruption leading to reduced pheromone detection holds great potential for RPW pest-control strategies.
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Affiliation(s)
- Alan Soffan
- King Saud University, Chair of Date Palm Research, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
| | - Binu Antony
- King Saud University, Chair of Date Palm Research, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
| | - Mahmoud Abdelazim
- King Saud University, Chair of Date Palm Research, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
| | - Paraj Shukla
- King Saud University, Chair of Date Palm Research, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
| | - Witjaksono Witjaksono
- Gadjah Mada University, Plant Protection Department, College of Agriculture, Yogyakarta 55281, Indonesia
| | - Saleh A. Aldosari
- King Saud University, Chair of Date Palm Research, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
| | - Abdulrahman S. Aldawood
- King Saud University, Plant Protection Department, College of Food and Agricultural Sciences, Riyadh 11451, Saudi Arabia
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Huang X, Liu L, Fang Y, Feng J. Expression of a Sensory Neuron Membrane Protein SNMP2 in Olfactory Sensilla of Codling Moth Cydia pomonella (Lepidoptera: Tortricidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1907-1913. [PMID: 27329623 DOI: 10.1093/jee/tow098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/18/2016] [Indexed: 06/06/2023]
Abstract
In insects, sensory neuron membrane proteins (SNMPs) are critical peripheral olfactory proteins and highly promote the sensitivity of pheromone detection. In this study, we cloned an SNMP transcript (CpomSNMP2, GenBank KU302714) from the antennae of the codling moth Cydia pomonella (L.) Its open reading frame is 1,575 bp and it encodes a protein with 524 amino acids. CpomSNMP2 contains two putative transmembrane domains and has a large extracellular loop. Phylogenetic analysis showed that CpomSNMP2 is clustered into the group of previously characterized lepidopteron SNMP2s. Expression levels of CpomSNMP2 were significantly higher in antennae of both males and females than in tissues from the thoraxes, abdomens, legs, and wings. CpomSNMP2 was distributed in sensilla trichodea of both males and females, but only in sensilla chaetica of males. This study provides evidence for olfactory roles of CpomSNMP2 in this moth.
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Affiliation(s)
- Xinglong Huang
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, Northwest A&F University, Yangling 712100, Shaanxi, China (; ; ; )
| | - Lu Liu
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, Northwest A&F University, Yangling 712100, Shaanxi, China (; ; ; )
| | - Yiqing Fang
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, Northwest A&F University, Yangling 712100, Shaanxi, China (; ; ; )
| | - Jinian Feng
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, Northwest A&F University, Yangling 712100, Shaanxi, China (; ; ; ),
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The B vitamins nicotinamide (B3) and riboflavin (B2) stimulate metamorphosis in larvae of the deposit-feeding polychaete Capitella teleta: implications for a sensory ligand-gated ion channel. PLoS One 2014; 9:e109535. [PMID: 25390040 PMCID: PMC4229104 DOI: 10.1371/journal.pone.0109535] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/08/2014] [Indexed: 01/28/2023] Open
Abstract
Marine sediments can contain B vitamins, presumably incorporated from settled, decaying phytoplankton and microorganisms associated with decomposition. Because B vitamins may be advantageous for the energetically intensive processes of metamorphosis, post-metamorphic growth, and reproduction, we tested several B vitamins to determine if they would stimulate larvae of the deposit-feeding polychaete Capitella teleta to settle and metamorphose. Nicotinamide and riboflavin individually stimulated larvae of C. teleta to settle and metamorphose, generally within 1–2 hours at nicotinamide concentrations as low as 3 µM and riboflavin concentrations as low as 50 µM. More than 80% of the larvae metamorphosed within 30 minutes at a nicotinamide concentration of 7 µM. The pyridine channel agonist pyrazinecarboxamide also stimulated metamorphosis at very low concentrations. In contrast, neither lumichrome, thiamine HCl, pyridoxine HCl, nor vitamin B12 stimulated larvae of C. teleta to metamorphose at concentrations as high as 500 µM. Larvae also did not metamorphose in response to either nicotinamide or pyrazinecarboxamide in calcium-free seawater or with the addition of 4-acetylpyridine, a competitive inhibitor of the pyridine receptor. Together, these results suggest that larvae of C. teleta are responding to nicotinamide and riboflavin via a chemosensory pyridine receptor similar to that previously reported to be present on crayfish chela and involved with food recognition. Our data are the first to implicate B vitamins as possible natural chemical settlement cues for marine invertebrate larvae.
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Obiero GFO, Mireji PO, Nyanjom SRG, Christoffels A, Robertson HM, Masiga DK. Odorant and gustatory receptors in the tsetse fly Glossina morsitans morsitans. PLoS Negl Trop Dis 2014; 8:e2663. [PMID: 24763191 PMCID: PMC3998910 DOI: 10.1371/journal.pntd.0002663] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 12/12/2013] [Indexed: 12/29/2022] Open
Abstract
Tsetse flies use olfactory and gustatory responses, through odorant and gustatory receptors (ORs and GRs), to interact with their environment. Glossina morsitans morsitans genome ORs and GRs were annotated using homologs of these genes in Drosophila melanogaster and an ab initio approach based on OR and GR specific motifs in G. m. morsitans gene models coupled to gene ontology (GO). Phylogenetic relationships among the ORs or GRs and the homologs were determined using Maximum Likelihood estimates. Relative expression levels among the G. m. morsitans ORs or GRs were established using RNA-seq data derived from adult female fly. Overall, 46 and 14 putative G. m. morsitans ORs and GRs respectively were recovered. These were reduced by 12 and 59 ORs and GRs respectively compared to D. melanogaster. Six of the ORs were homologous to a single D. melanogaster OR (DmOr67d) associated with mating deterrence in females. Sweet taste GRs, present in all the other Diptera, were not recovered in G. m. morsitans. The GRs associated with detection of CO2 were conserved in G. m. morsitans relative to D. melanogaster. RNA-sequence data analysis revealed expression of GmmOR15 locus represented over 90% of expression profiles for the ORs. The G. m. morsitans ORs or GRs were phylogenetically closer to those in D. melanogaster than to other insects assessed. We found the chemoreceptor repertoire in G. m. morsitans smaller than other Diptera, and we postulate that this may be related to the restricted diet of blood-meal for both sexes of tsetse flies. However, the clade of some specific receptors has been expanded, indicative of their potential importance in chemoreception in the tsetse. Tsetse flies navigate their environments using chemosensory receptors, which permit them to locate hosts, mating partners, and resting and larviposition sites. The genome of G. m. morsitans was interrogated for coding genes of odorant receptors (ORs) and gustatory receptors (GRs) that express in antennae and maxillary palp, and detect the volatile and soluble chemical signals. The signals are then transmitted to the central nervous system and translated to phenotypes. Majority of these genes in G. m. morsitans were spread across different scaffolds, but a few were found to occur in clusters, which suggested possible co-regulation of their expression. The number of ORs and GRs were much reduced in the G. m. morsitans genome, including the apparent loss of receptors for sugar when compared to selected Diptera. There was also an apparent numerical expansion of some receptors, presumably to maximize on their restricted blood-meal diet. The annotation of the chemoreceptor package of G. m. morsitans provides a resource for investigating key activities of tsetse flies that could be exploited for their control.
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Affiliation(s)
- George F. O. Obiero
- Molecular Biology and Bioinformatics Unit, International Center of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- South African Bioinformatics Institute (SANBI), South African MRC Bioinformatics Unit, University of the Western Cape, Bellville, South Africa
| | - Paul O. Mireji
- Department of Biochemistry and Molecular Biology, Egerton University, Njoro, Kenya
| | - Steven R. G. Nyanjom
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Alan Christoffels
- South African Bioinformatics Institute (SANBI), South African MRC Bioinformatics Unit, University of the Western Cape, Bellville, South Africa
| | - Hugh M. Robertson
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Daniel K. Masiga
- Molecular Biology and Bioinformatics Unit, International Center of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- * E-mail:
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Keil TA. Sensory cilia in arthropods. ARTHROPOD STRUCTURE & DEVELOPMENT 2012; 41:515-34. [PMID: 22814269 DOI: 10.1016/j.asd.2012.07.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 05/11/2023]
Abstract
In arthropods, the modified primary cilium is a structure common to all peripheral sensory neurons other than photoreceptors. Since its first description in 1958, it has been investigated in great detail in numerous sense organs (sensilla) of many insect species by means of electron microscopy and electrophysiology. The perfection of molecular biological methods has led to an enormous advance in our knowledge about development and function of sensory cilia in the fruitfly since the end of the last century. The cilia show a wealth of adaptations according to their different physiological roles: chemoreception, mechanoreception, hygroreception, and thermoreception. Divergent types of receptors and channels have evolved fulfilling these tasks. The number of olfactory receptor genes can be close to 300 in ants, whereas in crickets slightest mechanical stimuli are detected by the interaction of extremely sophisticated biomechanical devices with mechanosensory cilia. Despite their enormous morphological and physiological divergence, sensilla and sensory cilia develop according to a stereotyped pattern. Intraflagellar transport genes have been found to be decisive for proper development and function.
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Affiliation(s)
- Thomas A Keil
- Max-Planck-Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany.
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Mishra D, Louis M, Gerber B. Adaptive adjustment of the generalization-discrimination balance in larval Drosophila. J Neurogenet 2011; 24:168-75. [PMID: 20807100 DOI: 10.3109/01677063.2010.498066] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Learnt predictive behavior faces a dilemma: predictive stimuli will never 'replay' exactly as during the learning event, requiring generalization. In turn, minute differences can become meaningful, prompting discrimination. To provide a study case for an adaptive adjustment of this generalization-discrimination balance, the authors ask whether Drosophila melanogaster larvae are able to either generalize or discriminate between two odors (1-octen-3-ol and 3-octanol), depending on the task. The authors find that after discriminatively rewarding one but not the other odor, larvae show conditioned preference for the rewarded odor. On the other hand, no odor specificity is observed after nondiscriminative training, even if the test involves a choice between both odors. Thus, for this odor pair at least, discrimination training is required to confer an odor-specific memory trace. This requires that there is at least some difference in processing between the two odors already at the beginning of the training. Therefore, as a default, there is a small yet salient difference in processing between 1-octen-3-ol and 3-octanol; this difference is ignored after nondiscriminative training (generalization), whereas it is accentuated by odor-specific reinforcement (discrimination). Given that, as the authors show, both faculties are lost in anosmic Or83b(1) mutants, this indicates an adaptive adjustment of the generalization-discrimination balance in larval Drosophila, taking place downstream of Or83b-expressing sensory neurons.
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Affiliation(s)
- Dushyant Mishra
- Biozentrum Am Hubland, Lehrstuhl für Neurobiologie und Genetik, Universität Würzburg, Würzburg, Germany
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15
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Tsitoura P, Andronopoulou E, Tsikou D, Agalou A, Papakonstantinou MP, Kotzia GA, Labropoulou V, Swevers L, Georgoussi Z, Iatrou K. Expression and membrane topology of Anopheles gambiae odorant receptors in lepidopteran insect cells. PLoS One 2010; 5:e15428. [PMID: 21082026 PMCID: PMC2972716 DOI: 10.1371/journal.pone.0015428] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 09/21/2010] [Indexed: 12/21/2022] Open
Abstract
A lepidopteran insect cell-based expression system has been employed to express three Anopheles gambiae odorant receptors (ORs), OR1 and OR2, which respond to components of human sweat, and OR7, the ortholog of Drosophila's OR83b, the heteromerization partner of all functional ORs in that system. With the aid of epitope tagging and specific antibodies, efficient expression of all ORs was demonstrated and intrinsic properties of the proteins were revealed. Moreover, analysis of the orientation of OR1 and OR2 on the cellular plasma membrane through the use of a novel ‘topology screen’ assay and FACS analysis demonstrates that, as was recently reported for the ORs in Drosophila melanogaster, mosquito ORs also have a topology different than their mammalian counterparts with their N-terminal ends located in the cytoplasm and their C-terminal ends facing outside the cell. These results set the stage for the production of mosquito ORs in quantities that should permit their detailed biochemical and structural characterization and the exploration of their functional properties.
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Affiliation(s)
- Panagiota Tsitoura
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Evi Andronopoulou
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Daniela Tsikou
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Adamantia Agalou
- Laboratory of Cellular Signaling and Molecular Pharmacology, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Maria P. Papakonstantinou
- Laboratory of Cellular Signaling and Molecular Pharmacology, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Georgia A. Kotzia
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Vassiliki Labropoulou
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Zafiroula Georgoussi
- Laboratory of Cellular Signaling and Molecular Pharmacology, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Kostas Iatrou
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research “Demokritos”, Athens, Greece
- * E-mail:
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16
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Fan Y, Sun P, Wang Y, He X, Deng X, Chen X, Zhang G, Chen X, Zhou N. The G protein-coupled receptors in the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2010; 40:581-591. [PMID: 20685615 DOI: 10.1016/j.ibmb.2010.05.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 05/07/2010] [Accepted: 05/27/2010] [Indexed: 05/29/2023]
Abstract
G protein-coupled receptors (GPCRs) are the largest and most versatile family of transmembrane receptors in the cell, occupying the highest hierarchical positions in the regulation of many physiological processes. Although they have been extensively studied in a number of model insects, there have been few investigations of GPCRs in large Lepidopterans, such as Bombyx mori, an organism that provides a means to perform detailed tissue expression analyses, which may help to characterize GPCRs and their ligands. In addition, B. mori, also known as the silkworm, is an insect of substantial economic importance, due to its use in silk production and traditional medicines. In this work, we computationally identified 90 putative GPCRs in B. mori, 33 of which represent novel proteins. These GPCRs were annotated and compared with their homologs in Drosophila melanogaster and Anopheles gambiae. Phylogenetics analyses of the GPCRs from these three insects showed that GPCRs may easily duplicate or disappear during insect evolution, especially in the neuropeptide and protein hormone receptor subfamily. Interestingly, we observed a decrease in the quantity and diversity of the stress-tolerance gene, Methuselah, in B. mori, which may be related to its long history of domestication. Moreover, the presence of many Bombyx-specific GPCRs suggests that neither Drosophila nor Anopheles is good representatives for the GPCRs in the Class Insecta.
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Affiliation(s)
- Yi Fan
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
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Gomez-Marin A, Duistermars BJ, Frye MA, Louis M. Mechanisms of odor-tracking: multiple sensors for enhanced perception and behavior. Front Cell Neurosci 2010; 4:6. [PMID: 20407585 PMCID: PMC2854573 DOI: 10.3389/fncel.2010.00006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 03/10/2010] [Indexed: 11/21/2022] Open
Abstract
Early in evolution, the ability to sense and respond to changing environments must have provided a critical survival advantage to living organisms. From bacteria and worms to flies and vertebrates, sophisticated mechanisms have evolved to enhance odor detection and localization. Here, we review several modes of chemotaxis. We further consider the relevance of a striking and recurrent motif in the organization of invertebrate and vertebrate sensory systems, namely the existence of two symmetrical olfactory sensors. By combining our current knowledge about the olfactory circuits of larval and adult Drosophila, we examine the molecular and neural mechanisms underlying robust olfactory perception and extend these analyses to recent behavioral studies addressing the relevance and function of bilateral olfactory input for gradient detection. Finally, using a comparative theoretical approach based on Braitenberg's vehicles, we speculate about the relationships between anatomy, circuit architecture and stereotypical orientation behaviors.
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Affiliation(s)
- Alex Gomez-Marin
- EMBL-CRG Systems Biology Unit, Centre for Genomic Regulation, Universitat Pompeu Fabra Barcelona, Spain
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Ionotropic and metabotropic mechanisms in chemoreception: 'chance or design'? EMBO Rep 2010; 11:173-9. [PMID: 20111052 DOI: 10.1038/embor.2010.8] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 01/07/2010] [Indexed: 12/29/2022] Open
Abstract
Chemosensory receptors convert an enormous diversity of chemical signals from the external world into a common language of electrical activity in the brain. Mammals and insects use several families of transmembrane receptor proteins to recognize distinct classes of volatile and non-volatile chemicals that are produced by conspecifics or other environmental sources. A comparison of the signalling mechanisms of mammalian and insect receptors has revealed an unexpected functional distinction: mammals rely almost exclusively on metabotropic ligand-binding receptors, which use second messenger signalling cascades to indirectly activate ion channels, whereas insects use ionotropic receptors, which are gated directly by chemical stimuli, thereby leading to neuronal depolarization. In this review, we consider possible reasons for this dichotomy, taking into account biophysical, cell biological, ecological and evolutionary influences on how information is extracted from chemosensory cues by these animal classes.
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