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Montaño-Campaz ML, Oliveira EE, Bacca T, Toro-Restrepo B, Dias LG. Sex-specific alterations in adaptive responses of Chironomus columbiensis triggered by imidacloprid chronic and acute sublethal exposures. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27601-1. [PMID: 37253916 DOI: 10.1007/s11356-023-27601-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/09/2023] [Indexed: 06/01/2023]
Abstract
The use of imidacloprid is a common pest control practice in the Neotropical region. However, the imidacloprid unintended sublethal effects on Neotropical aquatic non-target arthropods and undesirable consequences for aquatic environments remain unclear. Here, we assessed the susceptibility of Chironomus columbiensis (Diptera: Chironomidae) larvae to the neonicotinoid imidacloprid and evaluated whether sublethal exposure types would trigger sex-dependent adaptive responses (e.g., emergence, body mass, reproduction, wing morphology). We conducted a concentration-mortality curve (96 h of exposure) and established chronic and acute sublethal exposure bioassays. While chronic sublethal exposures consisted of exposing individuals during their entire larval and pupal stages, the acute sublethal exposures represented a single short duration (24 h) exposure episode during either the first or fourth larval instar. Our results revealed that chronic sublethal exposure reduced the body mass of males, while acute sublethal exposures during the first instar resulted in heavier males than those that were not exposed to imidacloprid. Chronic exposure also reduced the reproduction of males and females, while the acute sublethal exposure only affected the reproduction of individuals that were imidacloprid-exposed on their later larval instar. Chronic and acute sublethal exposures did differentially affect the wing properties of C. columbiensis males (e.g., increased size when chronically exposed and highly asymmetric wings when acutely exposed in early larval phase) and females (e.g., highly asymmetric wings when chronically and acutely exposed). Collectively, our findings demonstrated that imidacloprid can cause unintended sublethal effects on C. columbiensis, and those effects are dependent on sex, exposure type, and developmental stage.
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Affiliation(s)
- Milton L Montaño-Campaz
- Programa de Doctorado, Facultad de Ciencias Agropecuarias, Grupo de Investigación Bionat, Universidad de Caldas, Manizales, Colombia
- Programa de Pós-Graduação Em Ecologia, Universidade Federal de Viçosa (UFV), Viçosa-MG, 36570-900, Brazil
| | - Eugênio E Oliveira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa-MG, 36570-900, Brazil.
| | - Tito Bacca
- Facultad de Ingeniería Agronómica, Universidad del Tolima, Tolima, Colombia
| | - Beatriz Toro-Restrepo
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas Y Naturales, Grupo de Investigación Bionat, Universidad de Caldas, Caldas, Colombia
| | - Lucimar G Dias
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas Y Naturales, Grupo de Investigación Bionat, Universidad de Caldas, Caldas, Colombia
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Chen W, Gu X, Yang YT, Batterham P, Perry T. Dual nicotinic acetylcholine receptor subunit gene knockouts reveal limits to functional redundancy. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 184:105118. [PMID: 35715057 DOI: 10.1016/j.pestbp.2022.105118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
The nicotinic acetylcholine receptor (nAChR) subunit gene family consists of ten members in Drosophila melanogaster. The mature nAChR is a pentamer assembled from these subunits. Despite recent advances in the in vitro expression of some receptor subunit combinations (nAChR subtypes), the in vivo combinations and stoichiometry of these subtypes remains poorly defined. In addition, there are many potential nAChR signalling roles for different subtypes in insect behaviour, development and physiology. Prior work has shown that nAChR subunit mutants can display altered sleep and mating behaviour, disrupted hormone signalling and reduced locomotion, climbing ability and longevity. Teasing out the specific receptor subunits that are involved in these different functions is potentially made more difficult given that the structural similarity between members of gene families often means that there is a degree of functional redundancy. In order to circumvent this, we created a dual knockout strain for the Dα1 and Dβ2 nAChR subunit genes and examined four traits including insecticide resistance. These subunits had been previously implicated in the response to a neonicotinoid insecticide, imidacloprid. The use of the dual knockout revealed that Dα1 and Dβ2 subunits are involved in signalling that leads to the inflation of wings following adult emergence from the pupal case. The Dβ1 subunit had previously been implicated as a contributor to this function. The lack of a phenotype or low penetrance of the phenotype in the Dα1 and Dβ2 single mutants compared to the dual knockout suggests that these subunits are, to some extent, functionally redundant. We also observed stronger reductions in climbing ability and longevity in the dual knockout. Our findings demonstrate that a dual knockout approach to examining members of the nAChR subunit gene family may increase the power of genetic approaches linking individual subunits and combinations thereof to particular biological functions. This approach will be valuable as the nAChRs are so widely expressed in the insect brain that they are likely to have many functions that hereto remain undetected.
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Affiliation(s)
- Wei Chen
- Bio21 Molecular Science and Biotechnology Institute, School of BioSciences, The University of Melbourne, Parkville 3010, Australia
| | - Xinyue Gu
- Bio21 Molecular Science and Biotechnology Institute, School of BioSciences, The University of Melbourne, Parkville 3010, Australia
| | - Ying Ting Yang
- Bio21 Molecular Science and Biotechnology Institute, School of BioSciences, The University of Melbourne, Parkville 3010, Australia
| | - Philip Batterham
- Bio21 Molecular Science and Biotechnology Institute, School of BioSciences, The University of Melbourne, Parkville 3010, Australia
| | - Trent Perry
- Bio21 Molecular Science and Biotechnology Institute, School of BioSciences, The University of Melbourne, Parkville 3010, Australia.
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Korona D, Dirnberger B, Giachello CNG, Queiroz RML, Popovic R, Müller KH, Minde DP, Deery MJ, Johnson G, Firth LC, Earley FG, Russell S, Lilley KS. Drosophila nicotinic acetylcholine receptor subunits and their native interactions with insecticidal peptide toxins. eLife 2022; 11:74322. [PMID: 35575460 PMCID: PMC9110030 DOI: 10.7554/elife.74322] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 04/19/2022] [Indexed: 12/14/2022] Open
Abstract
Drosophila nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that represent a target for insecticides. Peptide neurotoxins are known to block nAChRs by binding to their target subunits, however, a better understanding of this mechanism is needed for effective insecticide design. To facilitate the analysis of nAChRs we used a CRISPR/Cas9 strategy to generate null alleles for all ten nAChR subunit genes in a common genetic background. We studied interactions of nAChR subunits with peptide neurotoxins by larval injections and styrene maleic acid lipid particles (SMALPs) pull-down assays. For the null alleles, we determined the effects of α-Bungarotoxin (α-Btx) and ω-Hexatoxin-Hv1a (Hv1a) administration, identifying potential receptor subunits implicated in the binding of these toxins. We employed pull-down assays to confirm α-Btx interactions with the Drosophila α5 (Dα5), Dα6, Dα7 subunits. Finally, we report the localisation of fluorescent tagged endogenous Dα6 during Drosophila CNS development. Taken together, this study elucidates native Drosophila nAChR subunit interactions with insecticidal peptide toxins and provides a resource for the in vivo analysis of insect nAChRs.
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Affiliation(s)
- Dagmara Korona
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Benedict Dirnberger
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom.,Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.,Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | - Carlo N G Giachello
- Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | - Rayner M L Queiroz
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Rebeka Popovic
- MRC Toxicology Unit, Gleeson Building, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom
| | - Karin H Müller
- Cambridge Advanced Imaging Centre, Department of Physiology, Development and Neuroscience/Anatomy Building, University of Cambridge, Cambridge, United Kingdom
| | - David-Paul Minde
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Michael J Deery
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Glynnis Johnson
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Lucy C Firth
- Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | - Fergus G Earley
- Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | - Steven Russell
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Kathryn S Lilley
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom
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Balachandra VK, Ghosh SK. Emerging roles of SWI/SNF remodelers in fungal pathogens. Curr Genet 2022; 68:195-206. [PMID: 35001152 DOI: 10.1007/s00294-021-01219-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 09/20/2021] [Accepted: 10/16/2021] [Indexed: 11/30/2022]
Abstract
Fungal pathogens constantly sense and respond to the environment they inhabit, and this interaction is vital for their survival inside hosts and exhibiting pathogenic traits. Since such responses often entail specific patterns of gene expression, regulators of chromatin structure contribute to the fitness and virulence of the pathogens by modulating DNA accessibility to the transcriptional machinery. Recent studies in several human and plant fungal pathogens have uncovered the SWI/SNF group of chromatin remodelers as an important determinant of pathogenic traits and provided insights into their mechanism of function. Here, we review these studies and highlight the differential functions of these remodeling complexes and their subunits in regulating fungal fitness and pathogenicity. As an extension of our previous study, we also show that loss of specific RSC subunits can predispose the human fungal pathogen Candida albicans cells to filamentous growth in a context-dependent manner. Finally, we consider the potential of targeting the fungal SWI/SNF remodeling complexes for antifungal interventions.
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Affiliation(s)
- Vinutha K Balachandra
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai, India
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Santanu K Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India.
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