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He L, Ding J, Yang SS, Zang YN, Pang JW, Xing D, Zhang LY, Ren N, Wu WM. Molecular-Weight-Dependent Degradation of Plastics: Deciphering Host-Microbiome Synergy Biodegradation of High-Purity Polypropylene Microplastics by Mealworms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6647-6658. [PMID: 38563431 DOI: 10.1021/acs.est.3c06954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The biodegradation of polypropylene (PP), a highly persistent nonhydrolyzable polymer, by Tenebrio molitor has been confirmed using commercial PP microplastics (MPs) (Mn 26.59 and Mw 187.12 kDa). This confirmation was based on the reduction of the PP mass, change in molecular weight (MW), and a positive Δδ13C in the residual PP. A MW-dependent biodegradation mechanism was investigated using five high-purity PP MPs, classified into low (0.83 and 6.20 kDa), medium (50.40 and 108.0 kDa), and high (575.0 kDa) MW categories to access the impact of MW on the depolymerization pattern and associated gene expression of gut bacteria and the larval host. The larvae can depolymerize/biodegrade PP polymers with high MW although the consumption rate and weight losses increased, and survival rates declined with increasing PP MW. This pattern is similar to observations with polystyrene (PS) and polyethylene (PE), i.e., both Mn and Mw decreased after being fed low MW PP, while Mn and/or Mw increased after high MW PP was fed. The gut microbiota exhibited specific bacteria associations, such as Kluyvera sp. and Pediococcus sp. for high MW PP degradation, Acinetobacter sp. for medium MW PP, and Bacillus sp. alongside three other bacteria for low MW PP metabolism. In the host transcriptome, digestive enzymes and plastic degradation-related bacterial enzymes were up-regulated after feeding on PP depending on different MWs. The T. molitor host exhibited both defensive function and degradation capability during the biodegradation of plastics, with high MW PP showing a relatively negative impact on the larvae.
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Affiliation(s)
- Lei He
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Jie Ding
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Yang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ya-Ni Zang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ji-Wei Pang
- CECEP Digital Technology Co., Ltd., China Energy Conservation and Environmental Protection Group, Beijing 100096, China
| | - Defeng Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Lu-Yan Zhang
- School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wei-Min Wu
- Department of Civil and Environmental Engineering, William & Cloy Codiga Resource Recovery Center, Stanford University, Stanford, California 94305, United States
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Kohatsu S, Tanabe N, Yamamoto D, Isono K. Which Sugar to Take and How Much to Take? Two Distinct Decisions Mediated by Separate Sensory Channels. Front Mol Neurosci 2022; 15:895395. [PMID: 35726300 PMCID: PMC9206540 DOI: 10.3389/fnmol.2022.895395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
In Drosophila melanogaster, gustatory receptor neurons (GRNs) for sugar taste coexpress various combinations of gustatory receptor (Gr) genes and are found in multiple sites in the body. To determine whether diverse sugar GRNs expressing different combinations of Grs have distinct behavioral roles, we examined the effects on feeding behavior of genetic manipulations which promote or suppress functions of GRNs that express either or both of the sugar receptor genesGr5a (Gr5a+ GRNs) and Gr61a (Gr61a+ GRNs). Cell-population-specific overexpression of the wild-type form of Gr5a (Gr5a+) in the Gr5a mutant background revealed that Gr61a+ GRNs localized on the legs and internal mouthpart critically contribute to food choice but not to meal size decisions, while Gr5a+ GRNs, which are broadly expressed in many sugar-responsive cells across the body with an enrichment in the labella, are involved in both food choice and meal size decisions. The legs harbor two classes of Gr61a expressing GRNs, one with Gr5a expression (Gr5a+/Gr61a+ GRNs) and the other without Gr5aexpression (Gr5a−/Gr61a+ GRNs). We found that blocking the Gr5a+ class in the entire body reduced the preference for trehalose and blocking the Gr5a- class reduced the preference for fructose. These two subsets of GRNsare also different in their central projections: axons of tarsal Gr5a+/Gr61a+ GRNs terminate exclusively in the ventral nerve cord, while some axons of tarsal Gr5a−/Gr61a+ GRNs ascend through the cervical connectives to terminate in the subesophageal ganglion. We propose that tarsal Gr5a+/Gr61a+ GRNs and Gr5a−/Gr61a+ GRNs represent functionally distinct sensory pathways that function differently in food preference and meal-size decisions.
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Affiliation(s)
- Soh Kohatsu
- Neuro-ICT Laboratory, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
- *Correspondence: Soh Kohatsu Kunio Isono
| | - Noriko Tanabe
- Fukuoka Junior College for Kindergarten Teachers, Fukuoka, Japan
| | - Daisuke Yamamoto
- Neuro-ICT Laboratory, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
| | - Kunio Isono
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- *Correspondence: Soh Kohatsu Kunio Isono
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Brand P, Ramírez SR, Leese F, Quezada-Euan JJG, Tollrian R, Eltz T. Rapid evolution of chemosensory receptor genes in a pair of sibling species of orchid bees (Apidae: Euglossini). BMC Evol Biol 2015; 15:176. [PMID: 26314297 PMCID: PMC4552289 DOI: 10.1186/s12862-015-0451-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 08/10/2015] [Indexed: 12/13/2022] Open
Abstract
Background Insects rely more on chemical signals (semiochemicals) than on any other sensory modality to find, identify, and choose mates. In most insects, pheromone production is typically regulated through biosynthetic pathways, whereas pheromone sensory detection is controlled by the olfactory system. Orchid bees are exceptional in that their semiochemicals are not produced metabolically, but instead male bees collect odoriferous compounds (perfumes) from the environment and store them in specialized hind-leg pockets to subsequently expose during courtship display. Thus, the olfactory sensory system of orchid bees simultaneously controls male perfume traits (sender components) and female preferences (receiver components). This functional linkage increases the opportunities for parallel evolution of male traits and female preferences, particularly in response to genetic changes of chemosensory detection (e.g. Odorant Receptor genes). To identify whether shifts in pheromone composition among related lineages of orchid bees are associated with divergence in chemosensory genes of the olfactory periphery, we searched for patterns of divergent selection across the antennal transcriptomes of two recently diverged sibling species Euglossa dilemma and E. viridissima. Results We identified 3185 orthologous genes including 94 chemosensory loci from five different gene families (Odorant Receptors, Ionotropic Receptors, Gustatory Receptors, Odorant Binding Proteins, and Chemosensory Proteins). Our results revealed that orthologs with signatures of divergent selection between E. dilemma and E. viridissima were significantly enriched for chemosensory genes. Notably, elevated signals of divergent selection were almost exclusively observed among chemosensory receptors (i.e. Odorant Receptors). Conclusions Our results suggest that rapid changes in the chemosensory gene family occurred among closely related species of orchid bees. These findings are consistent with the hypothesis that strong divergent selection acting on chemosensory receptor genes plays an important role in the evolution and diversification of insect pheromone systems. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0451-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Philipp Brand
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitätsstrasse 150, D-44801, Bochum, Germany. .,Department for Evolution and Ecology, Center for Population Biology, University of California Davis, One Shields Avenue, 95616, Davis, USA.
| | - Santiago R Ramírez
- Department for Evolution and Ecology, Center for Population Biology, University of California Davis, One Shields Avenue, 95616, Davis, USA.
| | - Florian Leese
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitätsstrasse 150, D-44801, Bochum, Germany. .,Present address: Faculty of Biology, Aquatic Ecosystems Research, University of Duisburg and Essen, Universitätsstrasse 5, D-45141, Essen, Germany.
| | | | - Ralph Tollrian
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitätsstrasse 150, D-44801, Bochum, Germany.
| | - Thomas Eltz
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitätsstrasse 150, D-44801, Bochum, Germany.
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Brandão MM, Spoladore L, Faria LCB, Rocha ASL, Silva-Filho MC, Palazzo R. Ancient DNA sequence revealed by error-correcting codes. Sci Rep 2015; 5:12051. [PMID: 26159228 PMCID: PMC4498232 DOI: 10.1038/srep12051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 06/16/2015] [Indexed: 11/09/2022] Open
Abstract
A previously described DNA sequence generator algorithm (DNA-SGA) using error-correcting codes has been employed as a computational tool to address the evolutionary pathway of the genetic code. The code-generated sequence alignment demonstrated that a residue mutation revealed by the code can be found in the same position in sequences of distantly related taxa. Furthermore, the code-generated sequences do not promote amino acid changes in the deviant genomes through codon reassignment. A Bayesian evolutionary analysis of both code-generated and homologous sequences of the Arabidopsis thaliana malate dehydrogenase gene indicates an approximately 1 MYA divergence time from the MDH code-generated sequence node to its paralogous sequences. The DNA-SGA helps to determine the plesiomorphic state of DNA sequences because a single nucleotide alteration often occurs in distantly related taxa and can be found in the alternative codon patterns of noncanonical genetic codes. As a consequence, the algorithm may reveal an earlier stage of the evolution of the standard code.
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Affiliation(s)
- Marcelo M Brandão
- 1] Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil [2] Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Larissa Spoladore
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Luzinete C B Faria
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
| | - Andréa S L Rocha
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
| | - Marcio C Silva-Filho
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Reginaldo Palazzo
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
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Turner TL, Miller PM. Investigating natural variation in Drosophila courtship song by the evolve and resequence approach. Genetics 2012; 191:633-42. [PMID: 22466043 PMCID: PMC3374323 DOI: 10.1534/genetics.112.139337] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 03/18/2012] [Indexed: 12/13/2022] Open
Abstract
A primary goal of population genetics is to determine the genetic basis of natural trait variation. We could significantly advance this goal by developing comprehensive genome-wide approaches to link genotype and phenotype in model organisms. Here we combine artificial selection with population-based resequencing to investigate the genetic basis of variation in the interpulse interval (IPI) of Drosophila melanogaster courtship song. We performed divergent selection on replicate populations for only 14 generations, but had considerable power to differentiate alleles that evolved due to selection from those that evolved stochastically. We identified a large number of variants that changed frequency in response to selection for this simple behavior, and they are highly underrepresented on the X chromosome. Though our power was adequate using this experimental technique, the ability to differentiate causal variants from those affected by linked selection requires further development.
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Affiliation(s)
- Thomas L Turner
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA.
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Bachmanov AA, Bosak NP, Floriano WB, Inoue M, Li X, Lin C, Murovets VO, Reed DR, Zolotarev VA, Beauchamp GK. Genetics of sweet taste preferences. FLAVOUR FRAG J 2011; 26:286-294. [PMID: 21743773 PMCID: PMC3130742 DOI: 10.1002/ffj.2074] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sweet taste is a powerful factor influencing food acceptance. There is considerable variation in sweet taste perception and preferences within and among species. Although learning and homeostatic mechanisms contribute to this variation in sweet taste, much of it is genetically determined. Recent studies have shown that variation in the T1R genes contributes to within- and between-species differences in sweet taste. In addition, our ongoing studies using the mouse model demonstrate that a significant portion of variation in sweetener preferences depends on genes that are not involved in peripheral taste processing. These genes are likely involved in central mechanisms of sweet taste processing, reward and/or motivation. Genetic variation in sweet taste not only influences food choice and intake, but is also associated with proclivity to drink alcohol. Both peripheral and central mechanisms of sweet taste underlie correlation between sweet-liking and alcohol consumption in animal models and humans. All these data illustrate complex genetics of sweet taste preferences and its impact on human nutrition and health. Identification of genes responsible for within- and between-species variation in sweet taste can provide tools to better control food acceptance in humans and other animals.
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Affiliation(s)
| | | | - Wely B Floriano
- Department of Chemistry, Lakehead University, Thunder Bay, ON, Canada
| | - Masashi Inoue
- Laboratory of Cellular Neurobiology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Xia Li
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - Cailu Lin
- Monell Chemical Senses Center, Philadelphia, PA, USA
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Isono K, Morita H. Molecular and cellular designs of insect taste receptor system. Front Cell Neurosci 2010; 4:20. [PMID: 20617187 PMCID: PMC2896210 DOI: 10.3389/fncel.2010.00020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 05/16/2010] [Indexed: 12/05/2022] Open
Abstract
The insect gustatory receptors (GRs) are members of a large G-protein coupled receptor family distantly related to the insect olfactory receptors. They are phylogenetically different from taste receptors of most other animals. GRs are often coexpressed with other GRs in single receptor neurons. Taste receptors other than GRs are also expressed in some neurons. Recent molecular studies in the fruitfly Drosophila revealed that the insect taste receptor system not only covers a wide ligand spectrum of sugars, bitter substances or salts that are common to mammals but also includes reception of pheromone and somatosensory stimulants. However, the central mechanism to perceive and discriminate taste information is not yet elucidated. Analysis of the primary projection of taste neurons to the brain shows that the projection profiles depend basically on the peripheral locations of the neurons as well as the GRs that they express. These results suggest that both peripheral and central design principles of insect taste perception are different from those of olfactory perception.
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Affiliation(s)
- Kunio Isono
- Graduate School of Information Sciences, Tohoku University Sendai, Japan
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Colomb J, Grillenzoni N, Ramaekers A, Stocker RF. Architecture of the primary taste center ofDrosophila melanogasterlarvae. J Comp Neurol 2007; 502:834-47. [PMID: 17436288 DOI: 10.1002/cne.21312] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A simple nervous system combined with stereotypic behavioral responses to tastants, together with powerful genetic and molecular tools, have turned Drosophila larvae into a very promising model for studying gustatory coding. Using the Gal4/UAS system and confocal microscopy for visualizing gustatory afferents, we provide a description of the primary taste center in the larval central nervous system. Essentially, gustatory receptor neurons target different areas of the subesophageal ganglion (SOG), depending on their segmental and sensory organ origin. We define two major and two smaller subregions in the SOG. One of the major areas is a target of pharyngeal sensilla, the other one receives inputs from both internal and external sensilla. In addition to such spatial organization of the taste center, circumstantial evidence suggests a subtle functional organization: aversive and attractive stimuli might be processed in the anterior and posterior part of the SOG, respectively. Our results also suggest less coexpression of gustatory receptors than proposed in prior studies. Finally, projections of putative second-order taste neurons seem to cover large areas of the SOG. These neurons may thus receive multiple gustatory inputs. This suggests broad sensitivity of secondary taste neurons, reminiscent of the situation in mammals.
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Affiliation(s)
- Julien Colomb
- Department of Biology and Program in Neuroscience, University of Fribourg, 1700 Fribourg, Switzerland.
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Benton R, Sachse S, Michnick SW, Vosshall LB. Atypical membrane topology and heteromeric function of Drosophila odorant receptors in vivo. PLoS Biol 2006; 4:e20. [PMID: 16402857 PMCID: PMC1334387 DOI: 10.1371/journal.pbio.0040020] [Citation(s) in RCA: 678] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 11/14/2005] [Indexed: 11/18/2022] Open
Abstract
Drosophila olfactory sensory neurons (OSNs) each express two odorant receptors (ORs): a divergent member of the OR family and the highly conserved, broadly expressed receptor OR83b. OR83b is essential for olfaction in vivo and enhances OR function in vitro, but the molecular mechanism by which it acts is unknown. Here we demonstrate that OR83b heterodimerizes with conventional ORs early in the endomembrane system in OSNs, couples these complexes to the conserved ciliary trafficking pathway, and is essential to maintain the OR/OR83b complex within the sensory cilia, where odor signal transduction occurs. The OR/OR83b complex is necessary and sufficient to promote functional reconstitution of odor-evoked signaling in sensory neurons that normally respond only to carbon dioxide. Unexpectedly, unlike all known vertebrate and nematode chemosensory receptors, we find that Drosophila ORs and OR83b adopt a novel membrane topology with their N-termini and the most conserved loops in the cytoplasm. These loops mediate direct association of ORs with OR83b. Our results reveal that OR83b is a universal and integral part of the functional OR in Drosophila. This atypical heteromeric and topological design appears to be an insect-specific solution for odor recognition, making the OR/OR83b complex an attractive target for the development of highly selective insect repellents to disrupt olfactory-mediated host-seeking behaviors of insect disease vectors. This study reveals a novel membrane topology for olfactory receptors in Drosophila and details the molecular mechanisms of receptor localization at the sensory cilia.
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Affiliation(s)
- Richard Benton
- 1Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, New York, United States of America
| | - Silke Sachse
- 1Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, New York, United States of America
| | - Stephen W Michnick
- 2Département de Biochimie, Université de Montréal, Montréal, Québec, Canada
| | - Leslie B Vosshall
- 1Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, New York, United States of America
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Abstract
Insect odor and taste receptors are highly sensitive detectors of food, mates, and oviposition sites. Following the identification of the first insect odor and taste receptors in Drosophila melanogaster, these receptors were identified in a number of other insects, including the malaria vector mosquito Anopheles gambiae; the silk moth, Bombyx mori; and the tobacco budworm, Heliothis virescens. The chemical specificities of many of the D. melanogaster receptors, as well as a few of the A. gambiae and B. mori receptors, have now been determined either by analysis of deletion mutants or by ectopic expression in in vivo or heterologous expression systems. Here we discuss recent advances in our understanding of the molecular and cellular basis of odor and taste coding in insects.
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Affiliation(s)
- Elissa A Hallem
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
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11
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Dahanukar A, Hallem EA, Carlson JR. Insect chemoreception. Curr Opin Neurobiol 2005; 15:423-30. [PMID: 16006118 DOI: 10.1016/j.conb.2005.06.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 06/28/2005] [Indexed: 11/19/2022]
Abstract
Insect chemoreception is mediated by a large and diverse superfamily of seven-transmembrane domain receptors. These receptors were first identified in Drosophila, but have since been found in other insects, including mosquitoes and moths. Expression and functional analysis of these receptors have been used to identify receptor ligands and to map receptors to functional classes of neurons. Many receptors detect general odorants or tastants, whereas some detect pheromones. The non-canonical receptor Or83b, which is highly conserved across insect orders, dimerizes with odorant and pheromone receptors and is required for efficient localization of these proteins to dendrites of sensory neurons. These studies provide a foundation for understanding the molecular and cellular basis of olfactory and gustatory coding.
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Affiliation(s)
- Anupama Dahanukar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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12
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Palsson A, Dodgson J, Dworkin I, Gibson G. Tests for the replication of an association between Egfr and natural variation in Drosophila melanogaster wing morphology. BMC Genet 2005; 6:44. [PMID: 16102176 PMCID: PMC1208880 DOI: 10.1186/1471-2156-6-44] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Accepted: 08/15/2005] [Indexed: 11/25/2022] Open
Abstract
Background Quantitative differences between individuals stem from a combination of genetic and environmental factors, with the heritable variation being shaped by evolutionary forces. Drosophila wing shape has emerged as an attractive system for genetic dissection of multi-dimensional traits. We utilize several experimental genetic methods to validation of the contribution of several polymorphisms in the Epidermal growth factor receptor (Egfr) gene to wing shape and size, that were previously mapped in populations of Drosophila melanogaster from North Carolina (NC) and California (CA). This re-evaluation utilized different genetic testcrosses to generate heterozygous individuals with a variety of genetic backgrounds as well as sampling of new alleles from Kenyan stocks. Results Only one variant, in the Egfr promoter, had replicable effects in all new experiments. However, expanded genotyping of the initial sample of inbred lines rendered the association non-significant in the CA population, while it persisted in the NC sample, suggesting population specific modification of the quantitative trait nucleotide QTN effect. Conclusion Dissection of quantitative trait variation to the nucleotide level can identify sites with replicable effects as small as one percent of the segregating genetic variation. However, the testcross approach to validate QTNs is both labor intensive and time-consuming, and is probably less useful than resampling of large independent sets of outbred individuals.
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Affiliation(s)
- Arnar Palsson
- Department of Genetics' North Carolina State University, Raleigh, NC 27695, USA
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA
| | - James Dodgson
- Department of Genetics' North Carolina State University, Raleigh, NC 27695, USA
- The Department of Biochemistry, University of Sussex, Brighton, BN1 9QG, UK
| | - Ian Dworkin
- Department of Genetics' North Carolina State University, Raleigh, NC 27695, USA
| | - Greg Gibson
- Department of Genetics' North Carolina State University, Raleigh, NC 27695, USA
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Takahashi A, Takano-Shimizu T. A high-frequency null mutant of an odorant-binding protein gene, Obp57e, in Drosophila melanogaster. Genetics 2005; 170:709-18. [PMID: 15802511 PMCID: PMC1450408 DOI: 10.1534/genetics.104.036483] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have found a null mutant of an odorant-binding protein, Obp57e, in Drosophila melanogaster. This frameshift mutation, which is a 10-bp deletion in the coding region, is at a high frequency in the Kyoto population and is also present in Taiwan and Africa. We have sequenced a 1.5-kb region including the tandemly duplicated gene, Obp57d, from 16 inbred lines sampled in Kyoto, Japan. The analyses showed a peak of nucleotide diversity and strong linkage disequilibrium around this mutation. This pattern suggests an elevated mutation rate or an influence of balancing selection in this region. The level of nucleotide divergence between D. melanogaster and D. simulans does not support the former possibility. Thus, this presence/absence polymorphism may be due to balancing selection, which takes advantage of the relatively weak functional constraint in members of a large gene family. In addition, the Obp57d gene region showed an excess of high-frequency-derived mutants that is consistent with a pattern predicted under positive natural selection.
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Affiliation(s)
- Aya Takahashi
- Division of Population Genetics, National Institute of Genetics, Mishima, Japan.
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