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Feng S, DeGrey SP, Guédot C, Schoville SD, Pool JE. Genomic Diversity Illuminates the Environmental Adaptation of Drosophila suzukii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.03.547576. [PMID: 37461625 PMCID: PMC10349955 DOI: 10.1101/2023.07.03.547576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Biological invasions carry substantial practical and scientific importance, and represent natural evolutionary experiments on contemporary timescales. Here, we investigated genomic diversity and environmental adaptation of the crop pest Drosophila suzukii using whole-genome sequencing data and environmental metadata for 29 population samples from its native and invasive range. Through a multifaceted analysis of this population genomic data, we increase our understanding of the D. suzukii genome, its diversity and its evolution, and we identify an appropriate genotype-environment association pipeline for our data set. Using this approach, we detect genetic signals of local adaptation associated with nine distinct environmental factors related to altitude, wind speed, precipitation, temperature, and human land use. We uncover unique functional signatures for each environmental variable, such as a prevalence of cuticular genes associated with annual precipitation. We also infer biological commonalities in the adaptation to diverse selective pressures, particularly in terms of the apparent contribution of nervous system evolution to enriched processes (ranging from neuron development to circadian behavior) and to top genes associated with all nine environmental variables. Our findings therefore depict a finer-scale adaptive landscape underlying the rapid invasion success of this agronomically important species.
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Affiliation(s)
- Siyuan Feng
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Samuel P. DeGrey
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - Christelle Guédot
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - Sean D. Schoville
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - John E. Pool
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
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Vaziri A, Khabiri M, Genaw BT, May CE, Freddolino PL, Dus M. Persistent epigenetic reprogramming of sweet taste by diet. SCIENCE ADVANCES 2020; 6:6/46/eabc8492. [PMID: 33177090 PMCID: PMC7673743 DOI: 10.1126/sciadv.abc8492] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/23/2020] [Indexed: 05/25/2023]
Abstract
Diets rich in sugar, salt, and fat alter taste perception and food preference, contributing to obesity and metabolic disorders, but the molecular mechanisms through which this occurs are unknown. Here, we show that in response to a high sugar diet, the epigenetic regulator Polycomb Repressive Complex 2.1 (PRC2.1) persistently reprograms the sensory neurons of Drosophila melanogaster flies to reduce sweet sensation and promote obesity. In animals fed high sugar, the binding of PRC2.1 to the chromatin of the sweet gustatory neurons is redistributed to repress a developmental transcriptional network that modulates the responsiveness of these cells to sweet stimuli, reducing sweet sensation. Half of these transcriptional changes persist despite returning the animals to a control diet, causing a permanent decrease in sweet taste. Our results uncover a new epigenetic mechanism that, in response to the dietary environment, regulates neural plasticity and feeding behavior to promote obesity.
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Affiliation(s)
- Anoumid Vaziri
- The Molecular, Cellular and Developmental Biology Graduate Program, The University of Michigan, Ann Arbor, MI 49109, USA
- Department of Molecular, Cellular and Developmental Biology, College of Literature, Science, and the Arts, The University of Michigan, Ann Arbor, MI 49109, USA
| | - Morteza Khabiri
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Brendan T Genaw
- Program in Biology, College of Literature, Science, and the Arts, The University of Michigan, Ann Arbor, MI, 48109, USA
| | - Christina E May
- Department of Molecular, Cellular and Developmental Biology, College of Literature, Science, and the Arts, The University of Michigan, Ann Arbor, MI 49109, USA
- The Neuroscience Graduate Program, The University of Michigan, Ann Arbor, MI 49109, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, The University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Monica Dus
- The Molecular, Cellular and Developmental Biology Graduate Program, The University of Michigan, Ann Arbor, MI 49109, USA.
- Department of Molecular, Cellular and Developmental Biology, College of Literature, Science, and the Arts, The University of Michigan, Ann Arbor, MI 49109, USA
- Program in Biology, College of Literature, Science, and the Arts, The University of Michigan, Ann Arbor, MI, 48109, USA
- The Neuroscience Graduate Program, The University of Michigan, Ann Arbor, MI 49109, USA
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Li Q, DeBeaubien NA, Sokabe T, Montell C. Temperature and Sweet Taste Integration in Drosophila. Curr Biol 2020; 30:2051-2067.e5. [PMID: 32330421 DOI: 10.1016/j.cub.2020.03.066] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/06/2020] [Accepted: 03/26/2020] [Indexed: 12/01/2022]
Abstract
Sugar-containing foods offered at cooler temperatures tend to be less appealing to many animals. However, the mechanism through which the gustatory system senses thermal input and integrates temperature and chemical signals to produce a given behavioral output is poorly understood. To study this fundamental problem, we used the fly, Drosophila melanogaster. We found that the palatability of sucrose is strongly reduced by modest cooling. Using Ca2+ imaging and electrophysiological recordings, we demonstrate that bitter gustatory receptor neurons (GRNs) and mechanosensory neurons (MSNs) are activated by slight cooling, although sugar neurons are insensitive to the same mild stimulus. We found that a rhodopsin, Rh6, is expressed and required in bitter GRNs for cool-induced suppression of sugar appeal. Our findings reveal that the palatability of sugary food is reduced by slightly cool temperatures through different sets of thermally activated neurons, one of which depends on a rhodopsin (Rh6) for cool sensation.
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Affiliation(s)
- Qiaoran Li
- Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Nicolas A DeBeaubien
- Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Takaaki Sokabe
- Division of Cell Signaling, National Institute for Physiological Sciences, and Thermal Biology Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Craig Montell
- Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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Raad H, Robichon A. The pleiotropic effects of Innexin genes expressed in Drosophila glia encompass wing chemosensory sensilla. J Neurosci Res 2019; 97:1319-1330. [PMID: 31257643 DOI: 10.1002/jnr.24485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 11/07/2022]
Abstract
The neuroanatomy of Drosophila wing chemosensilla and the analysis of their sensory organ precursor cell lineage have demonstrated that they are surprisingly related to taste perception. The microarchitecture of wing bristles limits the use of electrophysiology methods to investigate wing chemosensory mechanisms. However, by monitoring the fluorescence of the complex calcium/GCaMP, calcium flux triggered upon tastant stimulation was observed within sensilla aligned along the wing anterior nerve. This string of fluorescent puncta was impaired in wings of Innexin 2 (Inx2) mutant flies; although it is unclear whether the Innexin proteins act at the level of the wing imaginal disc, adult wing and/or at both levels. Glial cells known to shelter Innexin(s) expression have no documented role in adult chemosensory sensilla. Our data suggest that Innexin(s) are likely required for the maturation of functional wing chemosensilla in adulthood. The unexpected presence of most Innexin transcripts in adult wing RNAseq data set argues for the expression of Innexin proteins in the larval imaginal wing disc that are continued in wing chemosensilla at adulthood. OPEN PRACTICES: This article has earned an Open Data badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available as supporting materials and includes the electronic lab notebook. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.
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Affiliation(s)
- Hussein Raad
- INRA, CNRS, Université Côte d'Azur, Institut Sophia Agrobiotech, Sophia Antipolis, France.,Lebanese International University, Mazraa, Lebanon
| | - Alain Robichon
- INRA, CNRS, Université Côte d'Azur, Institut Sophia Agrobiotech, Sophia Antipolis, France
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Sparks JT, Botsko G, Swale DR, Boland LM, Patel SS, Dickens JC. Membrane Proteins Mediating Reception and Transduction in Chemosensory Neurons in Mosquitoes. Front Physiol 2018; 9:1309. [PMID: 30294282 PMCID: PMC6158332 DOI: 10.3389/fphys.2018.01309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/30/2018] [Indexed: 12/17/2022] Open
Abstract
Mosquitoes use chemical cues to modulate important behaviors such as feeding, mating, and egg laying. The primary chemosensory organs comprising the paired antennae, maxillary palps and labial palps are adorned with porous sensilla that house primary sensory neurons. Dendrites of these neurons provide an interface between the chemical environment and higher order neuronal processing. Diverse proteins located on outer membranes interact with chemicals, ions, and soluble proteins outside the cell and within the lumen of sensilla. Here, we review the repertoire of chemosensory receptors and other membrane proteins involved in transduction and discuss the outlook for their functional characterization. We also provide a brief overview of select ion channels, their role in mammalian taste, and potential involvement in mosquito taste. These chemosensory proteins represent targets for the disruption of harmful biting behavior and disease transmission by mosquito vectors.
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Affiliation(s)
- Jackson T Sparks
- Biology Department, High Point University, High Point, NC, United States
| | - Gina Botsko
- Biology Department, High Point University, High Point, NC, United States
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Linda M Boland
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Shriraj S Patel
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Joseph C Dickens
- Department of Biology, University of Richmond, Richmond, VA, United States
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Naganos S, Ueno K, Horiuchi J, Saitoe M. Learning defects in Drosophila growth restricted chico mutants are caused by attenuated adenylyl cyclase activity. Mol Brain 2016; 9:37. [PMID: 27048332 PMCID: PMC4822261 DOI: 10.1186/s13041-016-0217-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/29/2016] [Indexed: 11/10/2022] Open
Abstract
Background Reduced insulin/insulin-like growth factor signaling (IIS) is a major cause of symmetrical intrauterine growth retardation (IUGR), an impairment in cell proliferation during prenatal development that results in global growth defects and mental retardation. In Drosophila, chico encodes the only insulin receptor substrate. Similar to other animal models of IUGR, chico mutants have defects in global growth and associative learning. However, the physiological and molecular bases of learning defects caused by chico mutations, and by symmetrical IUGR, are not clear. Results In this study, we found that chico mutations impair memory-associated synaptic plasticity in the mushroom bodies (MBs), neural centers for olfactory learning. Mutations in chico reduce expression of the rutabaga-type adenylyl cyclase (rut), leading to decreased cAMP synthesis in the MBs. Expressing a rut+ transgene in the MBs restores memory-associated plasticity and olfactory associative learning in chico mutants, without affecting growth. Thus chico mutations disrupt olfactory learning, at least in part, by reducing cAMP signaling in the MBs. Conclusions Our results suggest that some cognitive defects associated with reduced IIS may occur, independently of developmental defects, from acute reductions in cAMP signaling.
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Affiliation(s)
- Shintaro Naganos
- Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya, 185-8506, Tokyo, Japan
| | - Kohei Ueno
- Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya, 185-8506, Tokyo, Japan
| | - Junjiro Horiuchi
- Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya, 185-8506, Tokyo, Japan
| | - Minoru Saitoe
- Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya, 185-8506, Tokyo, Japan.
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Abstract
Five canonical tastes, bitter, sweet, umami (amino acid), salty, and sour (acid), are detected by animals as diverse as fruit flies and humans, consistent with a near-universal drive to consume fundamental nutrients and to avoid toxins or other harmful compounds. Surprisingly, despite this strong conservation of basic taste qualities between vertebrates and invertebrates, the receptors and signaling mechanisms that mediate taste in each are highly divergent. The identification over the last two decades of receptors and other molecules that mediate taste has led to stunning advances in our understanding of the basic mechanisms of transduction and coding of information by the gustatory systems of vertebrates and invertebrates. In this Review, we discuss recent advances in taste research, mainly from the fly and mammalian systems, and we highlight principles that are common across species, despite stark differences in receptor types.
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Affiliation(s)
- Emily R Liman
- Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Yali V Zhang
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Craig Montell
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA; Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
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Affiliation(s)
- Youngseok Lee
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, Korea
| | - Seeta Poudel
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, Korea
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Duvall LB, Taghert PH. E and M circadian pacemaker neurons use different PDF receptor signalosome components in drosophila. J Biol Rhythms 2013; 28:239-48. [PMID: 23929551 DOI: 10.1177/0748730413497179] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We used real-time imaging to detect cAMP levels in neurons of intact fly brains to study the mechanisms of circadian pacemaker synchronization by the neuropeptide pigment dispersing factor (PDF) in Drosophila. PDF receptor (PDF-R) is expressed by both M (sLNv) and E (LNd) pacemaker subclasses and is coupled to G(sα) in both cases. We previously reported that PDF-R in M pacemakers elevates cAMP levels by activating the ortholog of mammalian adenylate cyclase 3 (AC3) but that AC3 disruptions had no effect on E pacemaker sensitivity to PDF. Here, we show that PDF-R in E pacemakers activates a different AC isoform, AC78C, an ortholog of mammalian AC8. Knockdown of AC78C by transgenic RNAi substantially reduces, but does not completely abrogate, PDF responses in these E pacemakers. The knockdown effect is intact when restricted to mature stages, suggesting a physiological and not a development role for AC78C in E pacemakers. The AC78C phenotype is rescued by the overexpression of AC78C but not by overexpression of the rutabaga AC. AC78C overexpression does not disrupt PDF responses in these E pacemakers, and neither AC78C knockdown nor its overexpression disrupted locomotor rhythms. Finally, knockdown of 2 AKAPs, nervy and AKAP200, partially reduces LNd PDF responses. These findings begin to identify the components of E pacemaker PDF-R signalosomes and indicate that they are distinct from PDF-R signalosomes in M pacemakers: we propose they contain AC78C and at least 1 other AC.
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Affiliation(s)
- Laura B Duvall
- Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Duvall LB, Taghert PH. The circadian neuropeptide PDF signals preferentially through a specific adenylate cyclase isoform AC3 in M pacemakers of Drosophila. PLoS Biol 2012; 10:e1001337. [PMID: 22679392 PMCID: PMC3367976 DOI: 10.1371/journal.pbio.1001337] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/12/2012] [Indexed: 12/19/2022] Open
Abstract
To synchronize a network of pacemakers in the Drosophila brain, a neuropeptide receptor specifically associates with adenylate cyclase 3 to create a “circadian signalosome.” The neuropeptide Pigment Dispersing Factor (PDF) is essential for normal circadian function in Drosophila. It synchronizes the phases of M pacemakers, while in E pacemakers it decelerates their cycling and supports their amplitude. The PDF receptor (PDF-R) is present in both M and subsets of E cells. Activation of PDF-R stimulates cAMP increases in vitro and in M cells in vivo. The present study asks: What is the identity of downstream signaling components that are associated with PDF receptor in specific circadian pacemaker neurons? Using live imaging of intact fly brains and transgenic RNAi, we show that adenylate cyclase AC3 underlies PDF signaling in M cells. Genetic disruptions of AC3 specifically disrupt PDF responses: they do not affect other Gs-coupled GPCR signaling in M cells, they can be rescued, and they do not represent developmental alterations. Knockdown of the Drosophila AKAP-like scaffolding protein Nervy also reduces PDF responses. Flies with AC3 alterations show behavioral syndromes consistent with known roles of M pacemakers as mediated by PDF. Surprisingly, disruption of AC3 does not alter PDF responses in E cells—the PDF-R(+) LNd. Within M pacemakers, PDF-R couples preferentially to a single AC, but PDF-R association with a different AC(s) is needed to explain PDF signaling in the E pacemakers. Thus critical pathways of circadian synchronization are mediated by highly specific second messenger components. These findings support a hypothesis that PDF signaling components within target cells are sequestered into “circadian signalosomes,” whose compositions differ between E and M pacemaker cell types. In the fruit fly Drosophila melanogaster, the neuropeptide Pigment Dispersing Factor (PDF) supports circadian function by synchronizing two types of pacemaker cells, M cells and E cells. The PDF receptor (PDF-R) is a G protein coupled receptor (GPCR) whose activation stimulates adenylate cyclase (AC), thereby elevating levels of the second messenger cAMP in many different pacemakers including M cells. Drosophila contains at least 12 genes that encode potential ACs. In this study, we identify the AC downstream of the PDF receptor specifically in M cells and show that PDF signals preferentially through AC3. However, other GPCRs in the very same cells do not rely on AC3. A different scaffolding protein also influences PDF responses in M cells, suggesting that signaling components are spatially grouped to allow for coupling of specific receptors with downstream components. Remarkably, in E pacemakers, AC3 disruptions have no effect. These findings suggest that distinct PDF circadian signals exist in M versus in E pacemakers, and more generally, we propose a mechanism to differentiate signaling pathways that use common components.
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Affiliation(s)
| | - Paul H. Taghert
- Department of Anatomy & Neurobiology, Washington University Medical School, St. Louis, Missouri, United States of America
- * E-mail:
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Kan H, Kataoka-Shirasugi N, Amakawa T. Multiple pathways from three types of sugar receptor sites to metabotropic transduction pathways of the blowfly: study by the whole cell-clamp experiments. Comp Biochem Physiol A Mol Integr Physiol 2011; 160:94-9. [PMID: 21624494 DOI: 10.1016/j.cbpa.2011.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/16/2011] [Accepted: 05/16/2011] [Indexed: 11/30/2022]
Abstract
Multiple pathways from three types of multiple receptor sites to three types of metabotropic signal transduction pathways were investigated in the whole cell-clamp experiments using isolated labellar sugar receptor neurons (cells) of the adult blowfly, Phormia regina. First, the concentration-response curves of three types of sweet taste components specialized to multiple receptor sites were obtained: sucrose for the pyranose sites (P-sites), fructose for the furanose sites (F-sites), and l-valine for the alkyl sites (R-sites). Next, the effects of inhibitors such as 2', 5'-dideoxyadenosine on adenylyl cyclase in the cAMP pathway, LY 83583 on guanylyl cyclase in the cGMP pathway, and U-73122 on phospholipase C in the IP₃ pathway were examined. The results showed that all of the inhibitors affected each specific target in the second-messenger transduction pathways. The obtained results verified that the P-site corresponded to the cAMP, the F-site to the cGMP, and the R-site to the IP₃ transduction pathway, and that these three signal pathways did not have crossing points.
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Affiliation(s)
- Hideko Kan
- Graduate School of Human Development and Environment, Kobe University; 3-11, Tsurukabuto, Nada, Kobe 657-8501, Japan
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12
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Hodoniczky J, Robinson GJ, McGraw EA, Rae AL. Fruit fly bioassay to distinguish "sweet" sugar structures. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:12885-12889. [PMID: 21077679 DOI: 10.1021/jf102458b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Palatable response to dietary sugars plays a significant role in influencing metabolic health. New structures are being explored with beneficial health properties, although consumer acceptance relies heavily on desirable sensory properties. Despite the importance of behavioral responses, the ability to elucidate structure-preference relationships of sugars is lacking. A wild population of Drosophila melanogaster was used as a model to perform pairwise comparisons across structural groups to characterize a fruit fly bioassay for assessing sugar preference. Preference was successfully described in structurally relevant terms, particularly through the ability to directly test sugars of related structures in addition to standard sucrose comparisons. The fruit fly bioassay also provided the first report on the relative preference for the β-linked sugar alcohol, gentiobiitol. In making reference to well-known human preferences, the bioassay also raises opportunities for greater understanding of behavioral response to sugar structures in general.
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Affiliation(s)
- Jason Hodoniczky
- CSIRO Plant Industry, 306 Carmody Road, St. Lucia, Queensland 4067, Australia
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Momiyama T. Developmental increase in D1-like dopamine receptor-mediated inhibition of glutamatergic transmission through P/Q-type channel regulation in the basal forebrain of rats. Eur J Neurosci 2010; 32:579-90. [PMID: 20718855 DOI: 10.1111/j.1460-9568.2010.07306.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Whole-cell patch-clamp recordings of non-N-methyl-d-aspartate glutamatergic excitatory postsynaptic currents (EPSCs) were carried out from cholinergic neurons in slices of basal forebrain (BF) of developing rats aged 21-42 postnatal days to elucidate postnatal developmental change in Ca(2+) channel subtypes involved in the transmission as well as that in dopamine D(1)-like receptor-mediated presynaptic inhibition. The amplitude of EPSCs was inhibited by bath application of omega-conotoxin GVIA (omega-CgTX; 3 microM) or omega-agatoxin-TK (omega-Aga-TK; 200 nM) throughout the age range examined, suggesting that multiple types of Ca(2+) channel are involved in the transmission. The EPSC fraction reduced by omega-CgTX decreased with age, whereas that reduced by omega-Aga-TK increased. Inhibition of the EPSCs by a D(1)-like receptor agonist, SKF 81297 (SKF; 30 microM) increased with age in parallel with the increase in omega-Aga-TK-induced inhibition. An activator of the adenylyl cyclase (AC) pathway, forskolin (FK; 10 microM) inhibited the EPSCs, and FK-induced inhibition also increased with age in parallel with the increase in SKF-induced inhibition. Throughout the age range examined, SKF showed no further inhibitory effect on the EPSCs after omega-Aga-TK- or FK-induced effect had reached steady-state. These findings suggest that D(1)-like receptor-mediated presynaptic inhibition of glutamate release onto cholinergic BF neurons increases with age, and that the change is coupled with a developmental increase in the contribution of P/Q-type Ca(2+) channels as well as a developmental increase in AC pathway contribution.
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Affiliation(s)
- Toshihiko Momiyama
- Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki 444-8787, Japan.
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14
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Bredendiek N, Hütte J, Steingräber A, Hatt H, Gisselmann G, Neuhaus EM. Go α is involved in sugar perception in Drosophila. Chem Senses 2010; 36:69-81. [PMID: 20940344 DOI: 10.1093/chemse/bjq100] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Detection of chemical compounds in food sources is based on the activation of 7 transmembrane gustatory receptors (GRs) in mammals and in insects such as Drosophila, although the receptors are not conserved between the classes. Different combinations of Drosophila GRs are involved in the detection of sugars, but the activated signaling cascades are largely unknown. Because 7 transmembrane receptors usually couple to G-proteins, we tried to unravel the intracellular signaling cascade in taste neurons by screening heterotrimeric G-protein mutant flies for gustatory deficits. We found the subunit Goα to be involved in feeding behavior and cell excitability by different transgenic and pharmacological approaches. Goα is involved in the detection of sucrose, glucose, and fructose, but not with trehalose and maltose. Our studies reveal that Goα plays an important role in the perception of some sweet tastants. Because the perception of other sweet stimuli was not affected by mutations in Goα, we also found strong indication for the existence of multiple signaling pathways in the insect gustatory system.
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Affiliation(s)
- Nico Bredendiek
- Cell Physiology, Ruhr-Universitaet Bochum, Universitaetsstrasse 150, 44780 Bochum, Germany
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15
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Liu J, Ward A, Gao J, Dong Y, Nishio N, Inada H, Kang L, Yu Y, Ma D, Xu T, Mori I, Xie Z, Xu XZS. C. elegans phototransduction requires a G protein-dependent cGMP pathway and a taste receptor homolog. Nat Neurosci 2010; 13:715-22. [PMID: 20436480 PMCID: PMC2882063 DOI: 10.1038/nn.2540] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 03/15/2010] [Indexed: 01/28/2023]
Abstract
The “eyeless” animal C. elegans possesses the sense of light and engages in phototaxis behavior mediated by photoreceptor cells. However, the molecular and cellular mechanisms underlying phototransduction in C. elegans remain largely unclear. By recording the photoreceptor neuron ASJ in wild-type and various mutant worms, here we show that phototransduction in ASJ is a G protein-mediated process and requires membrane-associated guanylate cyclases but not typical cGMP-cleaving phosphodiesterases (PDEs). In addition, we find that C. elegans phototransduction requires LITE-1, a candidate photoreceptor protein known to be a member of the invertebrate taste receptor family. Genetic, pharmacological and electrophysiological data suggest a model whereby LITE-1 transduces light signals in ASJ through G-protein signaling, which leads to up-regulation of the second messenger cGMP followed by opening of cGMP-sensitive CNG channels and thereby stimulation of photoreceptor cells. Our results identify a phototransduction cascade in C. elegans and implicate the function of a “taste receptor" in phototransduction.
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Affiliation(s)
- Jie Liu
- Life Sciences Institute, Department of Molecular and Integrative Physiology, and Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
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