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İnak E, De Rouck S, Demirci B, Dermauw W, Geibel S, Van Leeuwen T. A novel target-site mutation (H146Q) outside the ubiquinone binding site of succinate dehydrogenase confers high levels of resistance to cyflumetofen and pyflubumide in Tetranychus urticae. Insect Biochem Mol Biol 2024:104127. [PMID: 38657708 DOI: 10.1016/j.ibmb.2024.104127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 04/26/2024]
Abstract
Mitochondrial electron transfer inhibitors at complex II (METI-II), also referred to as succinate dehydrogenase inhibitors (SDHI), represent a recently developed class of acaricides encompassing cyflumetofen, cyenopyrafen, pyflubumide and cyetpyrafen. Despite their novelty, resistance has already developed in the target pest, Tetranychus urticae. In this study a new mutation, H146Q in a highly conserved region of subunit B of complex II, was identified in a T. urticae population resistant to all METI-IIs. In contrast to previously described mutations, H146Q is located outside the ubiquinone binding site of complex II. Marker-assisted backcrossing of this mutation in a susceptible genetic background validated its association with resistance to cyflumetofen and pyflubumide, but not cyenopyrafen or cyetpyrafen. Biochemical assays and the construction of inhibition curves with isolated mitochondria corroborated this selectivity. In addition, phenotypic effects of H146Q, together with the previously described H258L, were further examined via CRISPR/Cas9 gene editing. Although both mutations were successfully introduced into a susceptible T. urticae population, the H146Q gene editing event was only recovered in individuals already harboring the I260V mutation, known to confer resistance towards cyflumetofen. The combination of H146Q+I260V conferred high resistance levels to all METI-II acaricides with LC50 values over 5000 mg a.i./L for cyflumetofen and pyflubumide. Similarly, the introduction of H258L via gene editing resulted in high resistance levels to all tested acaricides, with extreme LC50 values (>5000 mg a.i./L) for cyenopyrafen and cyetpyrafen, but lower resistance levels for pyflubumide and cyflumetofen. Together, these findings indicate that different mutations result in a different cross-resistance spectrum, probably also reflecting subtle differences in the binding mode of complex II acaricides.
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Affiliation(s)
- Emre İnak
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; Department of Plant Protection, Faculty of Agriculture, Ankara University, 06135, Ankara, Türkiye
| | - Sander De Rouck
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Berke Demirci
- Graduate School of Natural and Applied Sciences, Ankara University, 06110, Ankara, Türkiye
| | - Wannes Dermauw
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Sven Geibel
- Bayer AG, Crop Science Division, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
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Katsavou E, Sarafoglou C, Balabanidou V, Skoufa E, Nauen R, Linka M, Geibel S, Denecke S, Vontas J. Characterisation of lepidopteran geranylgeranyl diphosphate synthase as a putative pesticide target. Insect Mol Biol 2024; 33:147-156. [PMID: 37962063 DOI: 10.1111/imb.12885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 10/11/2023] [Indexed: 11/15/2023]
Abstract
Geranylgeranyl pyrophosphate (diphosphate) synthase (GGPPS) plays an important role in various physiological processes in insects, such as isoprenoid biosynthesis and protein prenylation. Here, we functionally characterised the GGPPS from the major agricultural lepidopteran pests Spodoptera frugiperda and Helicoverpa armigera. Partial disruption of GGPPS by CRISPR in S. frugiperda decreased embryo hatching rate and larval survival, suggesting that this gene is essential. Functional expression in vitro of Helicoverpa armigera GGPPS in Escherichia coli revealed a catalytically active enzyme. Next, we developed and optimised an enzyme assay to screen for potential inhibitors, such as the zoledronate and the minodronate, which showed a dose-dependent inhibition. Phylogenetic analysis of GGPPS across insects showed that GGPPS is highly conserved but also revealed several residues likely to be involved in substrate binding, which were substantially different in bee pollinator and human GGPPS. Considering the essentiality of GGPPS and its putative binding residue variability qualifies a GGPPS as a novel pesticide target. The developed assay may contribute to the identification of novel insecticide leads.
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Affiliation(s)
- Evangelia Katsavou
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Athens, Greece
| | - Chara Sarafoglou
- Department of Biology, University of Crete, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Vasileia Balabanidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Evangelia Skoufa
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Ralf Nauen
- R&D Pest Control, Crop Science Division, Bayer AG, Monheim am Rhein, Germany
| | - Marc Linka
- R&D Pest Control, Crop Science Division, Bayer AG, Monheim am Rhein, Germany
| | - Sven Geibel
- R&D Pest Control, Crop Science Division, Bayer AG, Monheim am Rhein, Germany
| | - Shane Denecke
- Department of Biology, University of Crete, Crete, Greece
- Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John Vontas
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Athens, Greece
- Department of Biology, University of Crete, Crete, Greece
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Wang Y, Buer B, Goodman CL, Kang D, Reall T, Dohn S, Ringbauer J, Li Y, Geibel S, Stanley D. Indomethacin and 20-hydroxyecdysone influence protein expression in a Spodoptera frugiperda nervous system cell line. Arch Insect Biochem Physiol 2024; 115:e22089. [PMID: 38409869 DOI: 10.1002/arch.22089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/23/2024] [Accepted: 01/31/2024] [Indexed: 02/28/2024]
Abstract
Insecticide mode of action studies provide insights into how new insecticidal actives function and contribute to assessing safety to humans and nontarget organisms. Insect cell lines that express potential target sites can serve as valuable tools in this effort. In this paper, we report on the influence of two signaling molecules on protein expression in a nervous system cell line established from Spodoptera frugiperda (Bayer/BCIRL-SfNS2-0714-TR). We selected this line because we established it in our laboratory and we are experienced in using it. Cells were exposed to the insect developmental hormone (1 µg/mL 20-hydroxyecdysone, 20E) and/or a cyclooxygenase (COX) inhibitor (25 μM indomethacin, INDO; inhibits prostaglandin [PG] biosynthesis) for 24 h (Day 2), 72 h (Day 4), or 120 h (Day 6). We selected a PG biosynthesis inhibitor because PGs act in many aspects of insect biology, such as embryonic development, immunity, and protein phosphorylation. We selected the developmental hormone, 20E, because it also acts in fundamental aspects of insect biology. We identified specific proteins via in silico analysis. Changes in protein expression levels were determined using liquid chromatography-mass spectrometry (MS) + MS-MS. The largest number of changes in protein expression occurred on Day 2. The combination of 20E plus INDO led to 222 differentially expressed proteins, which documents the deep significance of PGs and 20E in insect biology. 20E and, separately, INDO led to changes in 30 proteins each (p value < 0.01; >2X or <0.5X-fold changes). We recorded changes in the expression of 9 or 12 proteins (20E), 10 or 6 proteins (INDO), and 21 or 20 proteins (20E + INDO) on D4 and D6, respectively. While the cell line was established from neuronal tissue, the differentially expressed proteins act in a variety of fundamental cell processes. In this paper, we moved beyond a list of proteins by providing detailed, Gene Ontology term analyses and enrichment, which offers an in-depth understanding of the influence of these treatments on the SfNS2 cells. Because proteins are active components of cell physiology in their roles as enzymes, receptors, elements of signaling transduction pathways, and cellular structures, changes in their expression levels under the influence of signaling molecules provide insights into their function in insect cell physiology.
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Affiliation(s)
- Yong Wang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Liaoning Engineering and Technology Research Center for Insect Resource, Shenyang, People's Republic of China
| | - Benjamin Buer
- Bayer AG, Research & Development, Crop Science, Monheim am Rhein, Germany
| | - Cynthia L Goodman
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, Columbia, Missouri, USA
| | - David Kang
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, Columbia, Missouri, USA
| | - Tamra Reall
- University of Missouri-Extension, Blue Springs, Missouri, USA
| | - Susanne Dohn
- Bayer AG, Research & Development, Crop Science, Monheim am Rhein, Germany
| | - Joseph Ringbauer
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, Columbia, Missouri, USA
| | - Yaofa Li
- Plant Protection Institute, Hebei Academy of Agricultural and Forestry Sciences/IPM Center of Hebei Province/Key Laboratory of Integrated Pest Management on Crops in Northern Region of North China, Ministry of Agriculture, Baoding, China
| | - Sven Geibel
- Bayer AG, Research & Development, Crop Science, Monheim am Rhein, Germany
| | - David Stanley
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, Columbia, Missouri, USA
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Njiru C, Saalwaechter C, Mavridis K, Vontas J, Geibel S, Wybouw N, Van Leeuwen T. The complex II resistance mutation H258Y in succinate dehydrogenase subunit B causes fitness penalties associated with mitochondrial respiratory deficiency. Pest Manag Sci 2023; 79:4403-4413. [PMID: 37394630 DOI: 10.1002/ps.7640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/31/2023] [Accepted: 07/03/2023] [Indexed: 07/04/2023]
Abstract
BACKGROUND The acaricides cyflumetofen, cyenopyrafen and pyflubumide inhibit the mitochondrial electron transport chain at complex II [succinate dehydrogenase (SDH) complex]. A target site mutation H258Y was recently discovered in a resistant strain of the spider mite pest Tetranychus urticae. H258Y causes strong cross-resistance between cyenopyrafen and pyflubumide, but not cyflumetofen. In fungal pests, fitness costs associated with substitutions at the corresponding H258 position that confer resistance to fungicidal SDH inhibitors have not been uncovered. Here, we used H258 and Y258 near-isogenic lines of T. urticae to quantify potential pleiotropic fitness effects on mite physiology. RESULTS The H258Y mutation was not associated with consistent significant changes of single generation life history traits and fertility life table parameters. In contrast, proportional Sanger sequencing and droplet digital polymerase chain reaction showed that the frequency of the resistant Y258 allele decreased when replicated 50:50 Y258:H258 experimentally evolving populations were maintained in an acaricide-free environment for approximately 12 generations. Using in vitro assays with mitochondrial extracts from resistant (Y258) and susceptible (H258) lines, we identified a significantly reduced SDH activity (48% lower activity) and a slightly enhanced combined complex I and III activity (18% higher activity) in the Y258 lines. CONCLUSION Our findings suggest that the H258Y mutation is associated with a high fitness cost in the spider mite T. urticae. Importantly, while it is the most common approach, it is clear that only comparing life history traits and life table fecundity does not allow to reliably estimate fitness costs of target site mutations in natural pest populations. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Christine Njiru
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | | | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Athens, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Athens, Greece
| | - Sven Geibel
- Crop Science Division, Bayer AG, Monheim, Germany
| | - Nicky Wybouw
- Terrestrial Ecology Unit, Department of Biology, Faculty of Science, Ghent University, Ghent, Belgium
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Schleker ASS, Rist M, Matera C, Damijonaitis A, Collienne U, Matsuoka K, Habash SS, Twelker K, Gutbrod O, Saalwächter C, Windau M, Matthiesen S, Stefanovska T, Scharwey M, Marx MT, Geibel S, Grundler FMW. Author Correction: Mode of action of fluopyram in plant-parasitic nematodes. Sci Rep 2023; 13:13748. [PMID: 37612331 PMCID: PMC10447416 DOI: 10.1038/s41598-023-40484-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023] Open
Affiliation(s)
- A Sylvia S Schleker
- Molecular Phytomedicine, University of Bonn, Karlrobert‑Kreiten‑Straße 13, 53115, Bonn, Germany.
| | - Marc Rist
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany.
| | - Christiane Matera
- Molecular Phytomedicine, University of Bonn, Karlrobert‑Kreiten‑Straße 13, 53115, Bonn, Germany
| | - Arunas Damijonaitis
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Ursel Collienne
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Koichi Matsuoka
- Molecular Phytomedicine, University of Bonn, Karlrobert‑Kreiten‑Straße 13, 53115, Bonn, Germany
| | - Samer S Habash
- Molecular Phytomedicine, University of Bonn, Karlrobert‑Kreiten‑Straße 13, 53115, Bonn, Germany
- BASF Vegetable Seeds, Napoleonsweg 152, 6083 AB, Nunhem, The Netherlands
| | - Katja Twelker
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Oliver Gutbrod
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Corinna Saalwächter
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Maren Windau
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Svend Matthiesen
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Tatyana Stefanovska
- Department of Entomology, National University of Life and Environmental Sciences, Kyiv, 03041, Ukraine
| | - Melanie Scharwey
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Michael T Marx
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Sven Geibel
- Research and Development, CropScience Division, Bayer AG, Alfred‑Nobel‑Str. 50, 40789, Monheim am Rhein, Germany
| | - Florian M W Grundler
- Molecular Phytomedicine, University of Bonn, Karlrobert‑Kreiten‑Straße 13, 53115, Bonn, Germany
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Darif N, Vogelsang K, Vorgia E, Schneider D, Deligianni E, Geibel S, Vontas J, Denecke S. Cell penetrating peptides are versatile tools for enhancing multimodal uptake into cells from pest insects. Pestic Biochem Physiol 2023; 190:105317. [PMID: 36740333 DOI: 10.1016/j.pestbp.2022.105317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/07/2022] [Accepted: 12/12/2022] [Indexed: 06/18/2023]
Abstract
Cell penetrating peptides (CPPs) are small peptides defined by their ability to deliver molecular cargo into cells. While the subject of frequent investigation for pharmaceutical drug delivery, little consideration has been given to the possibility of CPPs for use as insecticides or insecticide enhancers. Here, we characterize the entry of four fluorescently tagged CPPs into two insect cell lines and dissected midgut tissues in terms of both total quantity and mode of penetration. Fluorescent microscopy showed that substantial amounts of CPPs penetrate the plasma membrane via endosomal uptake in ovarian (Sf9) and midgut derived (AW1) lepidopteran cells and that this process was sensitive to selected endocytosis inhibitors. Differences in the quantity of uptake was observed between CPPs, and further differences were found in the ability CPP-1838 to efficiently penetrate membranes through passive diffusion. These findings were extended to primary midgut derived cells and dissected tissues suggesting that CPPs show a preference for goblet cells and that CPP-1838 shows far higher rates of penetration. CPP-1838 thus shows extraordinary abilities to penetrate cells efficiency in both a diffusional and endocytotic manner. From these results more sophisticated delivery methods based on the utilization of CPPs can be developed.
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Affiliation(s)
- Nedal Darif
- Bayer AG, Applied Physics, Engineering & Technology, Leverkusen, Germany
| | | | - Elena Vorgia
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - David Schneider
- Bayer AG, Applied Physics, Engineering & Technology, Leverkusen, Germany
| | - Elena Deligianni
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Sven Geibel
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany.
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece; Pesticide Science Lab, Department of Crop Science, Agricultural University of Athens, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.
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Mermans C, Dermauw W, Geibel S, Van Leeuwen T. Activity, selection response and molecular mode of action of the isoxazoline afoxolaner in Tetranychus urticae. Pest Manag Sci 2023; 79:183-193. [PMID: 36116012 DOI: 10.1002/ps.7187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/13/2022] [Accepted: 09/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Afoxolaner is a novel representative of the isoxazolines, a class of ectoparasiticides which has been commercialized for the control of tick and flea infestations in dogs. In this study, the biological efficacy of afoxolaner against the two-spotted spider mite Tetranychus urticae was evaluated. Furthermore, as isoxazolines are known inhibitors of γ-aminobutyric acid-gated chloride channels (GABACls), the molecular mode of action of afoxolaner on T. urticae GABACls (TuRdls) was studied using functional expression in Xenopus oocytes followed by two-electrode voltage-clamp (TEVC) electrophysiology, and results were compared with inhibition by fluralaner, fipronil and endosulfan. To examine the influence of known GABACl resistance mutations, H301A, I305T and A350T substitutions in TuRdl1 and a S301A substitution in TuRdl2 were introduced. RESULTS Bioasassays revealed excellent efficacy of afoxolaner against all developmental stages and no cross-resistance was found in a panel of strains resistant to most currently used acaricides. Laboratory selection over a period of 3 years did not result in resistance. TEVC revealed clear antagonistic activity of afoxolaner and fluralaner for all homomeric TuRdl1/2/3 channels. The introduction of single, double or triple mutations to TuRdl1 and TuRdl2 did not lower channel sensitivity. By contrast, both endosulfan and fipronil had minimal antagonistic activities against TuRdl1/2/3, and channels carrying single mutations, whereas the sensitivity of double and triple TuRdl1 mutants was significantly increased. CONCLUSIONS Our results demonstrate that afoxolaner is a potent antagonist of GABACls of T. urticae and has a powerful mode of action to control spider mites. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Catherine Mermans
- Department of Plants and Crops | Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wannes Dermauw
- Department of Plants and Crops | Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Merelbeke, Belgium
| | - Sven Geibel
- CropScience Division, Bayer AG, Monheim, Germany
| | - Thomas Van Leeuwen
- Department of Plants and Crops | Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Samantsidis GR, Fotiadou M, Tzavellas S, Geibel S, Nauen R, Swevers L, Denecke S, Vontas J. Functional characterization of putative ecdysone transporters in lepidopteran pests. Insect Biochem Mol Biol 2022; 151:103830. [PMID: 36064128 DOI: 10.1016/j.ibmb.2022.103830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 06/15/2023]
Abstract
The insect steroid hormone ecdysone plays a critical role in insect development. Several recent studies have shown that ecdysone enters cells through Organic Anion Transporting Polypeptides (OATPs) in insects such as flies and mosquitoes. However, the conservation of this mechanism across other arthropods and the role of this transporter in canonical ecdysone pathways are less well studied. Herein we functionally characterized the putative ecdysone importer (EcI) from two major agricultural moth pests: Helicoverpa armigera (cotton bollworm) and Spodoptera frugiperda (fall armyworm). Phylogenetic analysis of OATP transporters across the superphylum Ecdysozoa revealed that EcI likely appeared only at the root of the arthropod lineage. Partial disruption of EcI in S. frugiperda decreased embryo hatching rate and larval survival, suggesting that this gene is essential for development in vivo. Depletion and re-expression of EcI in the lepidoptera cell line RP-HzGUT-AW1(MG) demonstrated this protein's ability to control ecdysone mediated signaling in gene regulation, its role in ecdysone mediated cell death, and its sensitivity to rifampicin, a well-known organic anion transporter inhibitor. Overall, this work sheds light on ecdysone uptake mechanisms across insect species and broadens our knowledge of the physiological roles of OATPs in the transportation of endogenous substrates.
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Affiliation(s)
- George-Rafael Samantsidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece; Department of Biology, University of Crete, Vassilika Vouton, 71409, Heraklion, Crete, Greece
| | - Melina Fotiadou
- Department of Biology, University of Crete, Vassilika Vouton, 71409, Heraklion, Crete, Greece
| | - Savvas Tzavellas
- Department of Biology, University of Crete, Vassilika Vouton, 71409, Heraklion, Crete, Greece
| | - Sven Geibel
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - Ralf Nauen
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, National Centre for Scientific Research Demokritos, Institute of Biosciences and Applications, 15310, Athens, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece; Department of Pathobiology, University of Pennsylvania, Philadelphia, United States.
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece; Pesticide Science Lab, Department of Crop Science, Agricultural University of Athens, Greece.
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İnak E, Alpkent YN, Saalwaechter C, Albayrak T, İnak A, Dermauw W, Geibel S, Van Leeuwen T. Long-term survey and characterization of cyflumetofen resistance in Tetranychus urticae populations from Turkey. Pestic Biochem Physiol 2022; 188:105235. [PMID: 36464352 DOI: 10.1016/j.pestbp.2022.105235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 06/17/2023]
Abstract
The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is the most economically important mite pest in agricultural areas and chemical acaricides are widely used to control T. urticae populations. Cyflumetofen is a recently introduced acaricide that inhibits the mitochondrial electron transport chain at complex II (succinate dehydrogenase, SDH), which represents the most recently developed mode of action for mite control worldwide. In the present study, started upon the launch of cyflumetofen in Turkey, a five-year survey was performed to monitor cyflumetofen susceptibility in 28 T. urticae populations collected from agricultural fields across the country. The first resistance case that might cause control failure in practical field conditions was uncovered in 2019, three years after the registration of cyflumetofen. In addition, an extremely resistant population (1722-fold resistance) was also detected towards the end of 2019. Cyflumetofen resistance did not decrease in the laboratory after relaxation of selection pressure for over one year in field-collected populations, suggesting the absence of a fitness cost associated with resistance in these populations. Next to phenotypic resistance, metabolic and physiological mechanisms underlying the decreased susceptibility were also investigated. Synergism assays showed the involvement of P450 monooxygenases in cyflumetofen resistance. Downregulation of carboxylesterases as resistance mechanism, is underpinned by the fact that pre-treatment with esterase inhibitor DEF decreased cyflumetofen toxicity in field-collected strains. Furthermore, a novel H258L substitution in the subunit B of complex II was uncovered in a field population. In silico modeling of the new mutation suggested that the mutation might indeed influence toxicity to complex II inhibitors cyenopyrafen and pyflubumide, but most likely not cyflumetofen. However, further studies are needed to uncover the exact role of this mutation in resistance to this new class of complex II inhibitors.
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Affiliation(s)
- Emre İnak
- Department of Plant Protection, Faculty of Agriculture, Ankara University, Diskapi 06110, Ankara, Turkey; Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Yasin Nazım Alpkent
- Republic of Turkey Ministry of Agriculture and Forestry Directorate of Plant Protection Central Research Institute, Ministry of Agriculture and Forestry, Yenimahalle 06172, Ankara, Turkey
| | | | - Tuba Albayrak
- Agricultural Credit Cooperatives of Turkey, Karapınar, 2863 Bucak, Burdur, Turkey
| | - Arda İnak
- Agro Project Academy, 01100 Seyhan, Adana, Turkey
| | - Wannes Dermauw
- Flanders Research Institute for Agriculture, Fisheries and Food, Plant Sciences Unit, Burg. Van Gansberghelaan 96, B-9820 Merelbeke, Belgium
| | - Sven Geibel
- Bayer AG, Crop Science Division, 40789 Monheim, Germany
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
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10
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Schleker ASS, Rist M, Matera C, Damijonaitis A, Collienne U, Matsuoka K, Habash SS, Twelker K, Gutbrod O, Saalwächter C, Windau M, Matthiesen S, Stefanovska T, Scharwey M, Marx MT, Geibel S, Grundler FMW. Mode of action of fluopyram in plant-parasitic nematodes. Sci Rep 2022; 12:11954. [PMID: 35831379 PMCID: PMC9279378 DOI: 10.1038/s41598-022-15782-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/29/2022] [Indexed: 11/10/2022] Open
Abstract
Plant-parasitic nematodes (PPN) are responsible for severe yield losses in crop production. Management is challenging as effective and safe means are rare. Recently, it has been discovered that the succinate dehydrogenase (SDH) inhibitor fluopyram is highly effective against PPN while accompanying an excellent safety profile. Here we show that fluopyram is a potent inhibitor of SDH in nematodes but not in mammals, insects and earthworm, explaining the selectivity on molecular level. As a consequence of SDH inhibition, fluopyram impairs ATP generation and causes paralysis in PPN and Caenorhabditis elegans. Interestingly, efficacy differences of fluopyram amongst PPN species can be observed. Permanent exposure to micromolar to nanomolar amounts of fluopyram prevents Meloidogyne spp. and Heterodera schachtii infection and their development at the root. Preincubation of Meloidogyne incognita J2 with fluopyram followed by a recovery period effectively reduces gall formation. However, the same procedure does not inhibit H. schachtii infection and development. Sequence comparison of sites relevant for ligand binding identified amino acid differences in SDHC which likely mediate selectivity, coincidently revealing a unique amino acid difference within SDHC conserved among Heterodera spp. Docking and C. elegans mutant studies suggest that this minute difference mediates altered sensitivity of H. schachtii towards fluopyram.
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Affiliation(s)
- A Sylvia S Schleker
- Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany.
| | - Marc Rist
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany.
| | - Christiane Matera
- Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany
| | - Arunas Damijonaitis
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Ursel Collienne
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Koichi Matsuoka
- Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany
| | - Samer S Habash
- Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany
- BASF Vegetable Seeds, Napoleonsweg 152, 6083 AB, Nunhem, The Netherlands
| | - Katja Twelker
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Oliver Gutbrod
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Corinna Saalwächter
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Maren Windau
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Svend Matthiesen
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Tatyana Stefanovska
- Department of Entomology, National University of Life and Environmental Sciences, Kyiv, 03041, Ukraine
| | - Melanie Scharwey
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Michael T Marx
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Sven Geibel
- Research and Development, CropScience Division, Bayer AG, Alfred-Nobel-Str.50, 40789, Monheim am Rhein, Germany
| | - Florian M W Grundler
- Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115, Bonn, Germany
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11
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De Beer B, Villacis-Perez E, Khalighi M, Saalwaechter C, Vandenhole M, Jonckheere W, Ismaeil I, Geibel S, Van Leeuwen T, Dermauw W. QTL mapping suggests that both cytochrome P450-mediated detoxification and target-site resistance are involved in fenbutatin oxide resistance in Tetranychus urticae. Insect Biochem Mol Biol 2022; 145:103757. [PMID: 35301092 DOI: 10.1016/j.ibmb.2022.103757] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/17/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
The organotin acaricide fenbutatin oxide (FBO) - an inhibitor of mitochondrial ATP-synthase - has been one of the most extensively used acaricides for the control of spider mites, and is still in use today. Resistance against FBO has evolved in many regions around the world but only few studies have investigated the molecular and genetic mechanisms of resistance to organotin acaricides. Here, we found that FBO resistance is polygenic in two genetically distant, highly resistant strains of the spider mite Tetranychus urticae, MAR-AB and MR-VL. To identify the loci underlying FBO resistance, two independent bulked segregant analysis (BSA) based QTL mapping experiments, BSA MAR-AB and BSA MR-VL, were performed. Two QTLs on chromosome 1 were associated with FBO resistance in each mapping experiment. At the second QTL of BSA MAR-AB, several cytochrome P450 monooxygenase (CYP) genes were located, including CYP392E4, CYP392E6 and CYP392E11, the latter being overexpressed in MAR-AB. Synergism tests further implied a role for CYPs in FBO resistance. Subunit c of mitochondrial ATP-synthase was located near the first QTL of both mapping experiments and harbored a unique V89A mutation enriched in the resistant parents and selected BSA populations. Marker-assisted introgression into a susceptible strain demonstrated a moderate but significant effect of the V89A mutation on toxicity of organotin acaricides. The impact of the mutation on organotin inhibition of ATP synthase was also functionally confirmed by ATPase assays on mitochondrial preparations. To conclude, our findings suggest that FBO resistance in the spider mite T. urticae is a complex interplay between CYP-mediated detoxification and target-site resistance.
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Affiliation(s)
- Berdien De Beer
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ernesto Villacis-Perez
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (UvA), Science Park 904, 1908, XH, Amsterdam, the Netherlands
| | - Mousaalreza Khalighi
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | | | - Marilou Vandenhole
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Wim Jonckheere
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ibrahim Ismaeil
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Sven Geibel
- Bayer AG, CropScience Division, 40789, Monheim, Germany
| | - Thomas Van Leeuwen
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
| | - Wannes Dermauw
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Burgemeester Van Gansberghelaan 96, 9820, Merelbeke, Belgium.
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12
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Denecke S, Bảo Lương HN, Koidou V, Kalogeridi M, Socratous R, Howe S, Vogelsang K, Nauen R, Batterham P, Geibel S, Vontas J. Characterization of a novel pesticide transporter and P-glycoprotein orthologues in Drosophila melanogaster. Proc Biol Sci 2022; 289:20220625. [PMID: 35582794 PMCID: PMC9114944 DOI: 10.1098/rspb.2022.0625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pesticides remain one of the most effective ways of controlling agricultural and public health insects, but much is still unknown regarding how these compounds reach their targets. Specifically, the role of ABC transporters in pesticide absorption and excretion is poorly understood, especially compared to the detailed knowledge about mammalian systems. Here, we present a comprehensive characterization of pesticide transporters in the model insect Drosophila melanogaster. An RNAi screen was performed, which knocked down individual ABCs in specific epithelial tissues and examined the subsequent changes in sensitivity to the pesticides spinosad and fipronil. This implicated a novel ABC drug transporter, CG4562, in spinosad transport, but also highlighted the P-glycoprotein orthologue Mdr65 as the most impactful ABC in terms of chemoprotection. Further characterization of the P-glycoprotein family was performed via transgenic overexpression and immunolocalization, finding that Mdr49 and Mdr50 play enigmatic roles in pesticide toxicology perhaps determined by their different subcellular localizations within the midgut. Lastly, transgenic Drosophila lines expressing P-glycoprotein from the major malaria vector Anopheles gambiae were used to establish a system for in vivo characterization of this transporter in non-model insects. This study provides the basis for establishing Drosophila as a model for toxicology research on drug transporters.
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Affiliation(s)
- Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 100N. Plastira Street, 700 13 Heraklion Crete, Greece
| | - Hằng Ngọc Bảo Lương
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 100N. Plastira Street, 700 13 Heraklion Crete, Greece
| | - Venetia Koidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 100N. Plastira Street, 700 13 Heraklion Crete, Greece,Department of Biology, University of Crete, Vassilika Vouton, 71409 Heraklion, Greece
| | - Maria Kalogeridi
- Department of Biology, University of Crete, Vassilika Vouton, 71409 Heraklion, Greece
| | - Rafaella Socratous
- Department of Biology, University of Crete, Vassilika Vouton, 71409 Heraklion, Greece
| | - Steven Howe
- School of BioSciences, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kathrin Vogelsang
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - Ralf Nauen
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - Philip Batterham
- School of BioSciences, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sven Geibel
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 100N. Plastira Street, 700 13 Heraklion Crete, Greece,Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, Greece
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13
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Njiru C, Saalwaechter C, Gutbrod O, Geibel S, Wybouw N, Van Leeuwen T. A H258Y mutation in subunit B of the succinate dehydrogenase complex of the spider mite Tetranychus urticae confers resistance to cyenopyrafen and pyflubumide, but likely reinforces cyflumetofen binding and toxicity. Insect Biochem Mol Biol 2022; 144:103761. [PMID: 35341907 DOI: 10.1016/j.ibmb.2022.103761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/18/2022] [Accepted: 03/22/2022] [Indexed: 06/14/2023]
Abstract
Succinate dehydrogenase (SDH) inhibitors such as cyflumetofen, cyenopyrafen and pyflubumide, are selective acaricides that control plant-feeding spider mite pests. Resistance development to SDH inhibitors has been investigated in a limited number of populations of the spider mite Tetranychus urticae and is associated with cytochrome P450 based detoxification and target-site mutations such as I260 T/V in subunit B and S56L in subunit C of SDH. Here, we report the discovery of a H258Y substitution in subunit B of SDH in a highly pyflubumide resistant population of T. urticae. As this highly conserved residue corresponds to one of the ubiquinone binding residues in fungi and bacteria, we hypothesized that H258Y could have a strong impact on SDH inhibitors toxicity. Marker assisted introgression and toxicity bioassays revealed that H258Y caused high cross resistance between cyenopyrafen and pyflubumide, but increased cyflumetofen toxicity. Resistance associated with H258Y was determined as dominant for cyenopyrafen, but recessive for pyflubumide. In vitro SDH assays with extracted H258 mitochondria showed that cyenopyrafen and the active metabolites of pyflubumide and cyflumetofen, interacted strongly with complex II. However, a clear shift in IC50s was observed for cyenopyrafen and the metabolite of pyflubumide when Y258 mitochondria were investigated. In contrast, the mutation slightly increased affinity of the cyflumetofen metabolite, likely explaining its increased toxicity for the mite lines carrying the substitution. Homology modeling and ligand docking further revealed that, although the three acaricides share a common binding motif in the Q-site of SDH, H258Y eliminated an important hydrogen bond required for cyenopyrafen and pyflubumide binding. In addition, the hydrogen bond between cyenopyrafen and Y117 in subunit D was also lost upon mutation. In contrast, cyflumetofen affinity was enhanced due to an additional hydrogen bond to W215 and hydrophobic interactions with the introduced Y258 in subunit B. Altogether, our findings not only highlight the importance of the highly conserved histidine residue in the binding of SDH inhibitors, but also reveal that a resistance mutation can provide both positive and negative cross-resistance within the same acaricide mode of action group.
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Affiliation(s)
- Christine Njiru
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Corinna Saalwaechter
- Bayer AG, Crop Science Division, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Oliver Gutbrod
- Bayer AG, Crop Science Division, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science Division, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Nicky Wybouw
- Terrestrial Ecology Unit, Department of Biology, Faculty of Science, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
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14
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Samantsidis GR, Denecke S, Swevers L, Skavdis G, Geibel S, Vontas J. Identification of Helicoverpa armigera promoters for biotechnological applications. Insect Biochem Mol Biol 2022; 142:103725. [PMID: 35093501 DOI: 10.1016/j.ibmb.2022.103725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Helicoverpa armigera and Helicoverpa zea are highly polyphagous major agricultural pests with a global distribution. Their control is based on insecticides, however, new, effective, and environmentally friendly control tools are required to be developed and validated. In an effort to facilitate the development of advanced biotechnological tools in these species that will take advantage of new powerful molecular biology techniques like CRISPR/Cas9, we used available transcriptomic data and literature resources, in order to identify RNA polymerase II and III promoters active in RP-HzGUT-AW1(MG), a midgut derived cell line from Helicoverpa zea. Following functional analysis in insect cell lines, four RNA polymerase II promoters from the genes HaLabial, HaTsp-2A, HaPtx-I and HaCaudal were found to exhibit high transcriptional activity in vitro. The HaTsp-2A promoter did not exhibit any activity in the non-midgut derived cell lines Sf-9 and Hi-5 despite high sequence conservation among Lepidoptera, suggesting that it may function in a gut specific manner. Furthermore, considering the utility of RNA polymerase III U6 promoters in methodologies such as RNAi and CRISPR/Cas9, we identified and evaluated four different U6 promoters of H. armigera. In vitro experiments based on luciferase and GFP reporter assays, as well as in vivo experiments targeting an essential gene of Helicoverpa, indicate that these U6 promoters are functional and can be used to experimentally silence or knockout target genes through the expression of shRNAs and sgRNAs respectively. Taking our findings together, we provide a set of promoters useful for the genetic manipulation of Helicoverpa species, that can be used in various applications in the context of agricultural biotechnology.
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Affiliation(s)
- George-Rafael Samantsidis
- Department of Biology, University of Crete, Vassilika Vouton, 71409, Heraklion, Crete, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, National Centre for Scientific Research Demokritos, Institute of Biosciences and Applications, 15310, Athens, Greece
| | - George Skavdis
- Department of Molecular Biology & Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Sven Geibel
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece; Pesticide Science Lab, Department of Crop Science, Agricultural University of Athens, Greece.
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15
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Ioannidis P, Buer B, Ilias A, Kaforou S, Aivaliotis M, Orfanoudaki G, Douris V, Geibel S, Vontas J, Denecke S. A spatiotemporal atlas of the lepidopteran pest Helicoverpa armigera midgut provides insights into nutrient processing and pH regulation. BMC Genomics 2022; 23:75. [PMID: 35073840 PMCID: PMC8785469 DOI: 10.1186/s12864-021-08274-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 10/20/2021] [Indexed: 12/13/2022] Open
Abstract
Background Caterpillars from the insect order Lepidoptera are some of the most widespread and destructive agricultural pests. Most of their impact is at the larval stage, where the midgut epithelium mediates the digestion and absorption of an astonishing amount of food. Although this tissue has been the subject of frequent investigation in Lepidoptera, a comprehensive expression atlas has yet to be generated. Results Here, we perform RNA-sequencing and proteomics on the gut of the polyphagous pest Helicoverpa armigera across, life stages, diet types, and compartments of the anterior-posterior axis. A striking relationship between the structural homology and expression pattern of a group of sugar transporters was observed in the early larval stages. Further comparisons were made among the spatial compartments of the midgut, which suggested a putative role for vATPases and SLC9 transporters in the generation of alkaline conditions in the H. armigera midgut. Conclusions This comprehensive resource will aid the scientific community in understanding lepidopteran gut physiology in unprecedented resolution. It is hoped that this study advances the understanding of the lepidopteran midgut and also facilitates functional work in this field. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08274-x.
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16
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Mehlhorn S, Hunnekuhl VS, Geibel S, Nauen R, Bucher G. Establishing RNAi for basic research and pest control and identification of the most efficient target genes for pest control: a brief guide. Front Zool 2021; 18:60. [PMID: 34863212 PMCID: PMC8643023 DOI: 10.1186/s12983-021-00444-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/04/2021] [Indexed: 11/14/2022] Open
Abstract
RNA interference (RNAi) has emerged as a powerful tool for knocking-down gene function in diverse taxa including arthropods for both basic biological research and application in pest control. The conservation of the RNAi mechanism in eukaryotes suggested that it should-in principle-be applicable to most arthropods. However, practical hurdles have been limiting the application in many taxa. For instance, species differ considerably with respect to efficiency of dsRNA uptake from the hemolymph or the gut. Here, we review some of the most frequently encountered technical obstacles when establishing RNAi and suggest a robust procedure for establishing this technique in insect species with special reference to pests. Finally, we present an approach to identify the most effective target genes for the potential control of agricultural and public health pests by RNAi.
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Affiliation(s)
- Sonja Mehlhorn
- Crop Science Division, Bayer AG, R&D, Pest Control, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, University of Göttingen, Göttingen, Germany
| | - Vera S Hunnekuhl
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, University of Göttingen, Göttingen, Germany
| | - Sven Geibel
- Crop Science Division, Bayer AG, R&D, Pest Control, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Ralf Nauen
- Crop Science Division, Bayer AG, R&D, Pest Control, Alfred-Nobel-Straße 50, 40789, Monheim, Germany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, University of Göttingen, Göttingen, Germany.
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17
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Denecke S, Rankić I, Driva O, Kalsi M, Luong NBH, Buer B, Nauen R, Geibel S, Vontas J. Comparative and functional genomics of the ABC transporter superfamily across arthropods. BMC Genomics 2021; 22:553. [PMID: 34281528 PMCID: PMC8290562 DOI: 10.1186/s12864-021-07861-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/23/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The ATP-binding cassette (ABC) transporter superfamily is comprised predominantly of proteins which directly utilize energy from ATP to move molecules across the plasma membrane. Although they have been the subject of frequent investigation across many taxa, arthropod ABCs have been less well studied. While the manual annotation of ABC transporters has been performed in many arthropods, there has so far been no systematic comparison of the superfamily within this order using the increasing number of sequenced genomes. Furthermore, functional work on these genes is limited. RESULTS Here, we developed a standardized pipeline to annotate ABCs from predicted proteomes and used it to perform comparative genomics on ABC families across arthropod lineages. Using Kruskal-Wallis tests and the Computational Analysis of gene Family Evolution (CAFE), we were able to observe significant expansions of the ABC-B full transporters (P-glycoproteins) in Lepidoptera and the ABC-H transporters in Hemiptera. RNA-sequencing of epithelia tissues in the Lepidoptera Helicoverpa armigera showed that the 7 P-glycoprotein paralogues differ substantially in their tissue distribution, suggesting a spatial division of labor. It also seems that functional redundancy is a feature of these transporters as RNAi knockdown showed that most transporters are dispensable with the exception of the highly conserved gene Snu, which is probably due to its role in cuticular formation. CONCLUSIONS We have performed an annotation of the ABC superfamily across > 150 arthropod species for which good quality protein annotations exist. Our findings highlight specific expansions of ABC transporter families which suggest evolutionary adaptation. Future work will be able to use this analysis as a resource to provide a better understanding of the ABC superfamily in arthropods.
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Affiliation(s)
- Shane Denecke
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece.
| | - Ivan Rankić
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czechia
| | - Olympia Driva
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece
| | - Megha Kalsi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece
| | - Ngoc Bao Hang Luong
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece
| | - Benjamin Buer
- CropScience Division, Bayer AG, R&D Pest Control, D-40789, Monheim, Germany
| | - Ralf Nauen
- CropScience Division, Bayer AG, R&D Pest Control, D-40789, Monheim, Germany
| | - Sven Geibel
- CropScience Division, Bayer AG, R&D Pest Control, D-40789, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece.,Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, Athens, Greece
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18
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Mehlhorn S, Ulrich J, Baden CU, Buer B, Maiwald F, Lueke B, Geibel S, Bucher G, Nauen R. The mustard leaf beetle, Phaedon cochleariae, as a screening model for exogenous RNAi-based control of coleopteran pests. Pestic Biochem Physiol 2021; 176:104870. [PMID: 34119215 DOI: 10.1016/j.pestbp.2021.104870] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 05/28/2023]
Abstract
RNA interference (RNAi) is a promising, selective pest control technology based on the silencing of targeted genes mediated by the degradation of mRNA after the ingestion of double-stranded (ds) RNA. However, the identification of the best target genes remains a challenge, because large scale screening is only feasible in lab model systems and it remains unclear, to what degree such data can be transferred to pest species. Here, we report on our efforts to transfer target genes found in a lab model to the mustard leaf beetle, Phaedon cochleariae. The mustard leaf beetle can be reared easily and resource-efficient in large quantities all year round and is an established chrysomelid pest for higher throughput screening approaches in the crop protection industry. Mustard leaf beetle transcriptome sequencing and assembly revealed genes orthologous to those previously described as highly efficient RNAi targets in the model beetle Tribolium castaneum. First, we observed mortality after injection of dsRNA targeting the respective orthologous genes in 2nd instar mustard beetle larvae. Next, we adopted a robust, automated multi-well plate foliar RNAi screening procedure with 2nd instar larvae of the mustard leaf beetle to assess those genes. Indeed, foliar application and oral uptake of dsRNA targeting the same genes resulted in larval mortality as well. The most effective target genes with a strong (lethal) phenotype - at dsRNA doses as low as 300 ng/leaf disc (equal to 9.6 g/ha) - were srp54k, rop, αSNAP, rpn7 and rpt3. Rather limited effects were observed after application of dsRNA targeting cactus, shibire and PP-α, though they had previously been shown to be highly lethal in red flour beetle. Importantly, our experiments demonstrated that the overall efficacy pattern obtained after oral dsRNA application was well correlated with the results obtained after dsRNA injection. RT-qPCR confirmed significant target gene knock-down after normalization by employing three reference genes shown to be stably expressed across life stages. In summary, several RNAi targeted genes elicited a strong lethal phenotype and significant target gene knock-down after feeding, suggesting P. cochleariae as a potential coleopteran screening model for foliarly applied exogenous RNAi.
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Affiliation(s)
- Sonja Mehlhorn
- Johann-Friedrich-Blumenbach-Institut, GZMB, Georg-August-Universität Göttingen, Justus von-Liebig-Weg 11, 37077 Göttingen, Germany; Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Julia Ulrich
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Christian U Baden
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Benjamin Buer
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Frank Maiwald
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Bettina Lueke
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Gregor Bucher
- Johann-Friedrich-Blumenbach-Institut, GZMB, Georg-August-Universität Göttingen, Justus von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany.
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Swevers L, Denecke S, Vogelsang K, Geibel S, Vontas J. Can the mammalian organoid technology be applied to the insect gut? Pest Manag Sci 2021; 77:55-63. [PMID: 32865304 DOI: 10.1002/ps.6067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/21/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Mammalian intestinal organoids are multicellular structures that closely resemble the structure of the intestinal epithelium and can be generated in vitro from intestinal stem cells under appropriate culture conditions. This technology has transformed pharmaceutical research and drug development in human medicine. For the insect gut, no biotechnological platform equivalent to organoid cultures has been described yet. Comparison of the regulation of intestinal homeostasis and growth between insects and mammals has revealed significant similarities but also important differences. In contrast to mammals, the differentiation potential of available insect cell lines is limited and can not be exploited for in vitro permeability assays to measure the uptake of insecticides. The successful development of in vitro models could be a result of the emergence of molecular mechanisms of self-organization and signaling in the intestine that are unique to mammals. It is nevertheless considered that the technology gap is a consequence of vast differences in knowledge, particularly with respect to culture conditions that maintain the differentation potential of insect midgut cells. From the viewpoint of pest control, advanced in vitro models of the insect midgut would be very desirable because of its key barrier function for orally ingested insecticides with hemolymphatic target and its role in insecticide resistance. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences & Applications, National Centre for Scientific Research "Demokritos", Agia Paraskevi, 15341, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | | | - Sven Geibel
- Bayer AG, Crop Science Devision, R&D Pest Control, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Pesticide Science Lab, Agricultural University of Athens, Athens, Greece
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20
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Vorgia E, Lamprousi M, Denecke S, Vogelsang K, Geibel S, Vontas J, Douris V. Functional characterization and transcriptomic profiling of a spheroid-forming midgut cell line from Helicoverpa zea (Lepidoptera: Noctuidae). Insect Biochem Mol Biol 2021; 128:103510. [PMID: 33276037 DOI: 10.1016/j.ibmb.2020.103510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/15/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Insect cell lines have been frequently used in insect science research in recent years. Establishment of cell lines from specialized tissues like the lepidopteran midgut is expected to facilitate research efforts towards the understanding of uptake and metabolic properties, as well as the design of assays for use in pesticide discovery. However, the number of available lines from specialized tissues of insects and the level of understanding of the biological processes taking place in insect cells is far behind mammalian systems. In this study we examine two established cell lines of insect midgut origin, investigate their growth parameters and amenability to transfection and genetic manipulation, and test their potential to form spheroid-like 3D structures. Our results indicate that a midgut-derived cell line from Helicoverpa zea, RP-HzGUT-AW1, is amenable to genetic manipulation by transfection with a standard insect expression vector and has excellent ability to form spheroids. To further investigate the differentiation status of this line, we examined for expression of several candidate marker genes from different midgut cell types, enterocytes (ECs), Goblet cells (GCs), enteroendocrine cells (EEs) and intestinal stem cells (ISCs), indicating that both certain ISC and certain differentiated cell markers were present. To acquire a more detailed perspective of the differentiation landscape of the specific cells, we performed an RNAseq analysis of RP-HzGUT-AW1 grown either in 2D or 3D cultures. We hypothesize that RP-HzGUT-AW1 are in an "arrested" developmental stage between ISC and terminal differentiation. Furthermore, an enrichment of stress response and oxidoreductase genes was observed in the spheroid samples while no significant difference was evident in differentiation markers between cells grown in 2D and 3D. These results render RP-HzGUT-AW1 as the most well-characterized insect gut derived cell line so far, and lay the groundwork for future work investigating midgut cell lines application potential.
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Affiliation(s)
- Elena Vorgia
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece
| | - Mantha Lamprousi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece; Department of Biology, University of Crete, Vassilika Vouton, 71409, Heraklion, Crete, Greece
| | - Shane Denecke
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece
| | - Kathrin Vogelsang
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - Sven Geibel
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece; Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, Greece
| | - Vassilis Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13, Heraklion Crete, Greece; Department of Biological Applications and Technology, University of Ioannina, 45110, Ioannina, Greece.
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21
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Denecke SM, Driva O, Luong HNB, Ioannidis P, Linka M, Nauen R, Geibel S, Vontas J. The Identification and Evolutionary Trends of the Solute Carrier Superfamily in Arthropods. Genome Biol Evol 2020; 12:1429-1439. [PMID: 32681801 PMCID: PMC7487162 DOI: 10.1093/gbe/evaa153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
The solute carrier (SLC) transporter superfamily comprises an ancient and ubiquitous group of proteins capable of translocating a range of nutrients, endogenous molecules, and xenobiotics. Although the group has been the subject of intense investigation in both bacteria and mammals, its systematic identification in arthropods has not yet been undertaken. Here, we present a genome-wide identification of all 66 human SLC families in 174 arthropod species. A pipeline (SLC_id) was constructed to identify and group SLCs using a combination of hidden Markov model and BLAST searches followed by filtering based on polypeptide length and the number of transmembrane domains. Comparative analysis of the number of transporters in each family across diverse arthropod lineages was accomplished using one-way analysis of variance (ANOVA) and the Computational Analysis of gene Family Evolution (CAFE). These results suggested that many SLC families have undergone expansions or contractions in particular evolutionary lineages. Notably, the sugar transporting SLC2 family was significantly larger in insects compared with arachnids. This difference may have been complemented by a rapid expansion of the SLC60 family in arachnids which also acts on dietary sugars. Furthermore, the SLC33 family underwent a recent and drastic expansion in aphids, although the biological relevance of this expansion was not possible to infer. Information on specific SLC transporter families across arthropod species can be accessed through an R shiny web application at http://chrysalida.imbb.forth.gr : 3838/Arthropod_SLC_Database/. The present study greatly facilitates further investigation of the diverse group of SLC transporters in arthropods.
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Affiliation(s)
- Shane M Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Olympia Driva
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Hang Ngoc Bao Luong
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Panagiotis Ioannidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Marc Linka
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - Ralf Nauen
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - Sven Geibel
- R&D Pest Control, Bayer AG, Crop Science Division, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Pesticide Science Lab, Department of Crop Science, Agricultural University of Athens, Greece
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22
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Mehlhorn SG, Geibel S, Bucher G, Nauen R. Profiling of RNAi sensitivity after foliar dsRNA exposure in different European populations of Colorado potato beetle reveals a robust response with minor variability. Pestic Biochem Physiol 2020; 166:104569. [PMID: 32448424 DOI: 10.1016/j.pestbp.2020.104569] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 05/10/2023]
Abstract
In recent years, substantial effort was spent on the exploration and implementation of RNAi technology using double-stranded RNA (dsRNA) for pest management purposes. However, only few studies investigated the geographical variation in RNAi sensitivity present in field-collected populations of the targeted insect pest. In this baseline study, 2nd instar larvae of 14 different European populations of Colorado potato beetle (CPB), Leptinotarsa decemlineata, collected from nine different countries were exposed to a foliarly applied diagnostic dose of dsactin (dsact) to test for possible variations in RNAi response. Only minor variability in RNAi sensitivity was observed between populations. However, the time necessary to trigger a dsRNA-mediated phenotypic response varied significantly among populations, indicated by significant differences in mortality figures obtained five days after treatment. An inbred German laboratory reference strain D01 and a Spanish field strain E02 showed almost 100% mortality after foliar exposure to 30 ng dsactin (equal to 0.96 g/ha), whereas another Spanish strain E01 was least responsive and showed only 30% mortality. Calculated LD50-values for foliarly applied dsact against strains D01 (most sensitive) and E01 (least sensitive) were 9.22 and 68.7 ng/leaf disc, respectively. The variability was not based on target gene sequence divergence or knock-down efficiency. Variability in expression of the core RNAi machinery genes dicer (dcr2a) and argonaute (ago2a) was observed but did not correlate with sensitivity. Interestingly, RT-qPCR data collected for all strains revealed a strong correlation between the expression level of dcr2a and ago2a (r 0.93) as well as ago2a and stauC (r 0.94), a recently described dsRNA binding protein in Coleopterans. Overall, this study demonstrates that sensitivity of CPB to sprayable RNAi slightly varies between strains but also shows that foliar RNAi as a control method works against all tested CPB populations collected across a broad geographic range in Europe. Thus, underpinning the potential of RNAi-based CPB control as a promising component in integrated pest management (IPM) and resistance management programs.
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Affiliation(s)
- Sonja G Mehlhorn
- Department of Evolutionary Developmental Genetics, Göttingen Center for Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany; Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, Göttingen Center for Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D, Pest Control, Alfred-Nobel-Str. 50, 40789 Monheim, Germany.
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23
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Riga M, Denecke S, Livadaras I, Geibel S, Nauen R, Vontas J. Development of efficient RNAi in Nezara viridula for use in insecticide target discovery. Arch Insect Biochem Physiol 2020; 103:e21650. [PMID: 31833096 DOI: 10.1002/arch.21650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/19/2019] [Accepted: 11/21/2019] [Indexed: 06/10/2023]
Abstract
Stink bugs are an emerging pest in many regions of the world but their molecular biology is still poorly understood. While several transcriptomes are available, the lack of validated gene manipulation tools like RNA interference (RNAi) in species such as the southern green stinkbug Nezara viridula precludes the characterization of individual genes in vivo. Such tools are particularly useful in performing high-throughput screens to search for essential genes that can be prioritized as potential insecticide targets. Here, we developed and optimized an efficient RNAi in N. viridula for use in insecticide target discovery and beyond. The visible marker Sex combs reduced and the essential gene Actin were used to verify the usability and efficiency of RNAi by microinjection at both the adult and nymphal stages, respectively, with nymphal approach presenting significant advantages. Following validation, RNAi was then used to measure lethality following the knockdown (KD) of two genes that are known insecticide targets, Chitin synthase, and Acetyl-CoA carboxylase. The KD of each gene resulted in >75% corrected mortality. These results indicate that RNAi is an effective tool in N. viridula and set a benchmark to evaluate potential targets in future RNAi screens aimed at insecticide target discovery.
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Affiliation(s)
- Maria Riga
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Ioannis Livadaras
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Sven Geibel
- Division Crop Science, Research and Development, Bayer AG, Monheim, Germany
| | - Ralf Nauen
- Division Crop Science, Research and Development, Bayer AG, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Department of Crop Science, Pesticide Science Laboratory, Agricultural University of Athens, Athens, Greece
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24
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Alavijeh ES, Khajehali J, Snoeck S, Panteleri R, Ghadamyari M, Jonckheere W, Bajda S, Saalwaechter C, Geibel S, Douris V, Vontas J, Van Leeuwen T, Dermauw W. Molecular and genetic analysis of resistance to METI-I acaricides in Iranian populations of the citrus red mite Panonychus citri. Pestic Biochem Physiol 2020; 164:73-84. [PMID: 32284140 DOI: 10.1016/j.pestbp.2019.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/22/2019] [Accepted: 12/27/2019] [Indexed: 06/11/2023]
Abstract
The citrus red mite, Panonychus citri, is a major pest on citrus all around the world. Mitochondrial Electron Transport Inhibitors of complex I (METI-I) acaricides such as fenpyroximate have been used extensively to control P. citri populations, which resulted in multiple reports of METI-I resistant populations in the field. In this study, biochemical and molecular mechanisms of fenpyroximate resistance were investigated in P. citri. Seven populations were collected from Northern provinces of Iran. Resistance ratios were determined and reached up to 75-fold in comparison to a fenpyroximate susceptible population. Cross-resistance to two additional METI-I acaricides, pyridaben and tebufenpyrad, was detected. PBO synergism experiments, in vivo enzyme assays and gene expression analysis suggest a minor involvement of cytochrome P450 monooxygenases in fenpyroximate resistance, which is in contrast with many reported cases for the closely related Tetranychus urticae. Next, we determined the frequency of a well-known mutation in the target-site of METI-Is, the PSST subunit, associated with METI-I resistance. Indeed, the H92R substitution was detected in a highly fenpyroximate resistant P. citri population. Additionally, a new amino acid substitution at a conserved site in the PSST subunit was detected, A94V, with higher allele frequencies in a moderately resistant population. Marker-assisted back-crossing in a susceptible background confirmed the potential involvement of the newly discovered A94V mutation in fenpyroximate resistance. However, introduction of the A94V mutation in the PSST homologue of D. melanogaster using CRISPR-Cas9 did not result in fenpyroximate resistant flies. In addition, differences in binding curves between METI-Is and complex I measured directly, in isolated transgenic and wildtype mitochondria preparations, could not be found.
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Affiliation(s)
- Elaheh Shafiei Alavijeh
- Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
| | - Jahangir Khajehali
- Department of Plant Protection, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
| | - Simon Snoeck
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Rafaela Panteleri
- Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-70013 Heraklion, Crete, Greece; Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology (FORTH), Nikolaou Plastira Street 100, 70013 Heraklion, Crete, Greece
| | - Mohammad Ghadamyari
- Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
| | - Wim Jonckheere
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Sabina Bajda
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | | | - Sven Geibel
- Bayer AG, CropScience Division, 40789 Monheim, Germany
| | - Vassilis Douris
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology (FORTH), Nikolaou Plastira Street 100, 70013 Heraklion, Crete, Greece; Department of Biological Applications and Technology, University of Ioannina, 451 10 Ioannina, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology (FORTH), Nikolaou Plastira Street 100, 70013 Heraklion, Crete, Greece; Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium.
| | - Wannes Dermauw
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium.
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25
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Denecke S, Ioannidis P, Buer B, Ilias A, Douris V, Topalis P, Nauen R, Geibel S, Vontas J. A transcriptomic and proteomic atlas of expression in the Nezara viridula (Heteroptera: Pentatomidae) midgut suggests the compartmentalization of xenobiotic metabolism and nutrient digestion. BMC Genomics 2020; 21:129. [PMID: 32028881 PMCID: PMC7006211 DOI: 10.1186/s12864-020-6459-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Stink bugs are an emerging threat to crop security in many parts of the globe, but there are few genetic resources available to study their physiology at a molecular level. This is especially true for tissues such as the midgut, which forms the barrier between ingested material and the inside of the body. RESULTS Here, we focus on the midgut of the southern green stink bug Nezara viridula and use both transcriptomic and proteomic approaches to create an atlas of expression along the four compartments of the anterior-posterior axis. Estimates of the transcriptome completeness were high, which led us to compare our predicted gene set to other related stink bugs and Hemiptera, finding a high number of species-specific genes in N. viridula. To understand midgut function, gene ontology and gene family enrichment analyses were performed for the most highly expressed and specific genes in each midgut compartment. These data suggested a role for the anterior midgut (regions M1-M3) in digestion and xenobiotic metabolism, while the most posterior compartment (M4) was enriched in transmembrane proteins. A more detailed characterization of these findings was undertaken by identifying individual members of the cytochrome P450 superfamily and nutrient transporters thought to absorb amino acids or sugars. CONCLUSIONS These findings represent an initial step to understand the compartmentalization and physiology of the N. viridula midgut at a genetic level. Future studies will be able to build on this work and explore the molecular physiology of the stink bug midgut.
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Affiliation(s)
- Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece.
| | - Panagiotis Ioannidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece.
| | - Benjamin Buer
- Bayer AG, Crop Science Division, R&D Pest Control, 40789, Monheim, Germany
| | - Aris Ilias
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece
| | - Vassilis Douris
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece.,Department of Biological Applications and Technology, University of Ioannina, 45110, Ioannina, Greece
| | - Pantelis Topalis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D Pest Control, 40789, Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science Division, R&D Pest Control, 40789, Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, N. Plastira 100, GR-70013, Heraklion, Crete, Greece.,Department of Crop Science, Agricultural University of Athens, Iera Odos 75, GR-11855, Athens, Greece
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26
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Boaventura D, Ulrich J, Lueke B, Bolzan A, Okuma D, Gutbrod O, Geibel S, Zeng Q, Dourado PM, Martinelli S, Flagel L, Head G, Nauen R. Molecular characterization of Cry1F resistance in fall armyworm, Spodoptera frugiperda from Brazil. Insect Biochem Mol Biol 2020; 116:103280. [PMID: 31740346 DOI: 10.1016/j.ibmb.2019.103280] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 05/21/2023]
Abstract
Fall armyworm, Spodoptera frugiperda (J.E. Smith) is a major lepidopteran pest of maize in Brazil and its control particularly relies on the use of genetically engineered crops expressing Bacillus thuringiensis (Bt) toxins such as Cry1F. However, control failures compromising the efficacy of this technology have been reported in many regions in Brazil, but the mechanism of Cry1F resistance in Brazilian fall armyworm populations remained elusive. Here we investigated the molecular mechanism of Cry1F resistance in two field-collected strains of S. frugiperda from Brazil exhibiting high levels of Cry1F resistance. We first rigorously evaluated several candidate reference genes for normalization of gene expression data across strains, larval instars and gut tissues, and identified ribosomal proteins L10, L17 and RPS3A to be most suitable. We then investigated the expression pattern of ten potential Bt toxin receptors/enzymes in both neonates and 2nd instar gut tissue of Cry1F resistant fall armyworm strains compared to a susceptible strain. Next we sequenced the ATP-dependent Binding Cassette subfamily C2 gene (ABCC2) and identified three mutated sites present in ABCC2 of both Cry1F resistant strains: two of them, a GY deletion (positions 788-789) and a P799 K/R amino acid substitution, located in a conserved region of ABCC2 extracellular loop 4 (EC4) and another amino acid substitution, G1088D, but in a less conserved region. We further characterized the role of the novel mutations present in EC4 by functionally expressing both wild type and mutated ABCC2 transporters in insect cell lines, and confirmed a critical role of both sites for Cry1F binding by cell viability assays. Finally, we assessed the frequency of the mutant alleles by pooled population sequencing and pyrosequencing in 40 fall armyworm populations collected from maize fields in different regions in Brazil. We found that the GY deletion being present at high frequency. However we also observed many rare alleles which disrupt residues between sites 783-799, and their diversity and abundance in field collected populations lends further support to the importance of the EC4 domain for Cry1F toxicity.
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Affiliation(s)
- Debora Boaventura
- Institute of Crop Science and Resource Conservation, University of Bonn, 53115, Bonn, Germany; Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Julia Ulrich
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Bettina Lueke
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Anderson Bolzan
- Department of Entomology and Acarology, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Daniela Okuma
- Bayer S.A, Crop Science, Av. Dr. Roberto Moreira, 5005, Paulinia, SP, Brazil
| | - Oliver Gutbrod
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Qin Zeng
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Patrick M Dourado
- Bayer S.A, Crop Science, R&D, Avenida Nacoes Unidas, São Paulo, Brazil
| | - Samuel Martinelli
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Lex Flagel
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Graham Head
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Ralf Nauen
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany.
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Reall T, Kraus S, Goodman CL, Ringbauer J, Geibel S, Stanley D. Next-generation cell lines established from the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae). In Vitro Cell Dev Biol Anim 2019; 55:686-693. [PMID: 31410641 DOI: 10.1007/s11626-019-00394-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/01/2019] [Indexed: 12/30/2022]
Abstract
The fall armyworm, Spodoptera frugiperda (Sf), is a polyphagous lepidopteran herbivore that consumes more than 80 plant species, including many economically important crops, such as corn, soybeans, and sorghum. While already a serious pest in the Americas, it was recently introduced into Africa, India, and China. Because of its high economic costs in the New World and the continent-wide damage potentials in Africa, research to develop advanced pest management technologies is necessary. We are supporting this need by developing novel, next-generation insect cell lines from targeted tissues. Cell lines, such as these, will boost insecticide discovery programs and lead to innovative pest management solutions. Here, we report on the establishment of 16 new cell lines from larval S. frugiperda tissues: nine from the central nervous system, three from the aorta, and four from the testes. We confirmed the identities of the cell lines by DNA amplification fingerprinting polymerase chain reaction, determined their doubling times from growth curves, and described cell types via microscopy. We also developed 16 sublines from three neuronal cell lines.
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Affiliation(s)
- Tamra Reall
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, 1503 South Providence Road, Columbia, MO, 65203, USA
| | | | - Cynthia L Goodman
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, 1503 South Providence Road, Columbia, MO, 65203, USA.
| | - Joseph Ringbauer
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, 1503 South Providence Road, Columbia, MO, 65203, USA
| | | | - David Stanley
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, 1503 South Providence Road, Columbia, MO, 65203, USA
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Gottert A, Friedland B, Geibel S, Nyblade L, Baral SD, Kentutsi S, Mallouris C, Sprague L, Hows J, Anam F, Amanyeiwe U, Pulerwitz J. The People Living with HIV (PLHIV) Resilience Scale: Development and Validation in Three Countries in the Context of the PLHIV Stigma Index. AIDS Behav 2019; 23:172-182. [PMID: 31350712 PMCID: PMC6773670 DOI: 10.1007/s10461-019-02594-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Supporting resilience among people living with HIV (PLHIV) is crucial to their sustained uptake of HIV services as well as psychological and social wellbeing. However, no measures exist to assess resilience specifically in relation to living with HIV. We developed the PLHIV Resilience Scale and evaluated its performance in surveys with 1207 PLHIV in Cameroon, Senegal and Uganda as part of the PLHIV Stigma Index-the most widely used tool to track stigma and discrimination among PLHIV worldwide. Factor analyses demonstrated satisfactory psychometric properties and reliability (alphas = 0.81-0.92). Levels of resilience (e.g., whether one's self-respect has been positively, negatively, or not affected by one's HIV status) varied substantially within and across countries. Higher resilience was associated with less depression in each country (all p < 0.001), and, in Cameroon and Uganda, better self-rated health and less experience of stigma/discrimination (all p < 0.001). The final 10-item PLHIV Resilience Scale can help inform interventions and policies.
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Affiliation(s)
- A Gottert
- Population Council HIV and AIDS Program, Washington, DC, USA.
| | - B Friedland
- Population Council HIV and AIDS Program, New York, NY, USA
| | - S Geibel
- Population Council HIV and AIDS Program, Washington, DC, USA
| | - L Nyblade
- RTI International, Washington, DC, USA
| | - S D Baral
- Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD, USA
- Center for Public Health and Human Rights, Johns Hopkins University, Baltimore, MD, USA
| | - S Kentutsi
- National Forum of PLHIV Networks in Uganda (NAFOPHANU), Kampala, Uganda
| | | | - L Sprague
- UNAIDS, Geneva, Switzerland
- The Global Network of People Living with HIV (GNP +), Amsterdam, The Netherlands
| | - J Hows
- The Global Network of People Living with HIV (GNP +), Amsterdam, The Netherlands
| | - F Anam
- International Community of WLHIV (ICW), Nairobi, Kenya
| | - U Amanyeiwe
- Prevention, Care and Treatment (PCT) Division, USAID Office of HIV/AIDS, Washington, DC, USA
| | - J Pulerwitz
- Population Council HIV and AIDS Program, Washington, DC, USA
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Mermans C, Dermauw W, Geibel S, Van Leeuwen T. A G326E substitution in the glutamate-gated chloride channel 3 (GluCl3) of the two-spotted spider mite Tetranychus urticae abolishes the agonistic activity of macrocyclic lactones. Pest Manag Sci 2017; 73:2413-2418. [PMID: 28736919 DOI: 10.1002/ps.4677] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The macrocyclic lactones abamectin and milbemectin are frequently used to control phytophagous mites such as Tetranychus urticae. Consequently, resistance has developed and was genetically linked with substitutions in the glutamate-gated chloride channel (GluCl) subunits TuGluCl1 and TuGluCl3. Here, we functionally validated a G326E substitution in TuGluCl3 by functional expression in Xenopus laevis oocytes followed by two-electrode voltage-clamp electrophysiology. RESULTS Homomeric wild-type and mutated GluCl3 were successfully expressed. l-glutamic-acid-induced currents exhibited a rapid onset equal in both channels and EC50 for l-glutamic-acid was in the micromolar range (384.2 μm and 292.7 μm, respectively). Abamectin and milbemycin A4 elicited sustained currents in wild-type GluCl3, but the G326E substitution completely abolished the agonistic activity of macrocyclic lactones. CONCLUSION A target-site mutation in Tu GluCl3 contributes to avermectin resistance in T. urticae. However, given the multitude of channel genes and the potential additive or synergistic effects of mutations, to what extent mutations determine the often extremely strong resistance phenotype in the field deserves further study. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Catherine Mermans
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wannes Dermauw
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sven Geibel
- Bayer AG, CropScience Division, Monheim, Germany
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Department of Evolutionary Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
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Geibel S, Lörinczi È, Bamberg E, Friedrich T. Voltage dependence of proton pumping by bacteriorhodopsin mutants with altered lifetime of the M intermediate. PLoS One 2013; 8:e73338. [PMID: 24019918 PMCID: PMC3760879 DOI: 10.1371/journal.pone.0073338] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/29/2013] [Indexed: 11/19/2022] Open
Abstract
The light-driven proton pump bacteriorhodopsin (BR) from Halobacterium salinarum is tightly regulated by the [H(+)] gradient and transmembrane potential. BR exhibits optoelectric properties, since spectral changes during the photocycle are kinetically controlled by voltage, which predestines BR for optical storage or processing devices. BR mutants with prolonged lifetime of the blue-shifted M intermediate would be advantageous, but the optoelectric properties of such mutants are still elusive. Using expression in Xenopus oocytes and two-electrode voltage-clamping, we analyzed photocurrents of BR mutants with kinetically destabilized (F171C, F219L) or stabilized (D96N, D96G) M intermediate in response to green light (to probe H(+) pumping) and blue laser flashes (to probe accumulation/decay of M). These mutants have divergent M lifetimes. As for BR-WT, this strictly correlates with the voltage dependence of H(+) pumping. BR-F171C and BR-F219L showed photocurrents similar to BR-WT. Yet, BR-F171C showed a weaker voltage dependence of proton pumping. For both mutants, blue laser flashes applied during and after green-light illumination showed reduced M accumulation and shorter M lifetime. In contrast, BR-D96G and BR-D96N exhibited small photocurrents, with nonlinear current-voltage curves, which increased strongly in the presence of azide. Blue laser flashes showed heavy M accumulation and prolonged M lifetime, which accounts for the strongly reduced H(+) pumping rate. Hyperpolarizing potentials augmented these effects. The combination of M-stabilizing and -destabilizing mutations in BR-D96G/F171C/F219L (BR-tri) shows that disruption of the primary proton donor Asp-96 is fatal for BR as a proton pump. Mechanistically, M destabilizing mutations cannot compensate for the disruption of Asp-96. Accordingly, BR-tri and BR-D96G photocurrents were similar. However, BR-tri showed negative blue laser flash-induced currents even without actinic green light, indicating that Schiff base deprotonation in BR-tri exists in the dark, in line with previous spectroscopic investigations. Thus, M-stabilizing mutations, including the triple mutation, drastically interfere with electrochemical H(+) gradient generation.
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Affiliation(s)
- Sven Geibel
- Max-Planck-Institute of Biophysics, Department of Biophysical Chemistry, Frankfurt am Main, Germany
| | - Èva Lörinczi
- Max-Planck-Institute of Biophysics, Department of Biophysical Chemistry, Frankfurt am Main, Germany
| | - Ernst Bamberg
- Max-Planck-Institute of Biophysics, Department of Biophysical Chemistry, Frankfurt am Main, Germany
| | - Thomas Friedrich
- Max-Planck-Institute of Biophysics, Department of Biophysical Chemistry, Frankfurt am Main, Germany
- Technical University of Berlin, Institute of Chemistry, Berlin, Germany
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Geibel S. Same-sex sexual behavior of men in Kenya: Implications for HIV prevention, programs, and policy. Facts Views Vis Obgyn 2012; 4:285-94. [PMID: 24753921 PMCID: PMC3987482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Unprotected anal sex has long been recognized as a risk factor for HIV transmission among men who have sex with men (MSM). In Africa, however, general denial of MSM existence and associated stigma discouraged research. To address this gap in the literature, partners conducted the first behavioral surveys of MSM in Kenya. The first study was to assess HIV risk among MSM in Nairobi, and the second study a pre-post intervention study of male sex workers in Mombasa. The 2004 behavioral survey of 500 men in Mombasa revealed that MSM were having multiple sexual partners and failed to access appropriate prevention counseling and care at Kenya clinics. A 2006 capture-recapture enumeration in Mombasa estimated that over 700 male sex workers were active, after which a pre-intervention baseline survey of 425 male sex workers was conducted. Awareness of unprotected anal sex as an HIV risk behavior and consistent condom use with clients was low, and use of oil-based lubricants high. Based on this information, peer educators were trained in HIV prevention, basic counseling skills, and distribution of condoms and lubricants. To assess impact of the interventions, a follow-up survey of 442 male sex workers was implemented in 2008. Exposure to peer educators was significantly associated with increased consistent condom use, improved HIV knowledge, and increased use of water-based lubricants. These results have provided needed information to the Government of Kenya and have informed HIV prevention interventions.
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Phan G, Remaut H, Allen W, Geibel S, Lebedev A, Henderson N, Thanassi D, Waksman G. Crystal structure of the usher:chaperone:adhesin subunit complex – insights into pilus assembly mechanism. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311099533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Gaiko O, Janausch I, Geibel S, Vollert H, Arndt P, Gonski S, Fendler K. Robust Electrophysiological Assays using Solid Supported Membranes: the Organic Cation Transporter OCT2. Aust J Chem 2011. [DOI: 10.1071/ch10322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An electrophysiological assay platform based on solid supported membranes (SSM) for the organic cation transporter (OCT) is presented. Stable Chinese hamster ovary (CHO) cell lines overexpressing the human (hOCT2) and rat transporters (rOCT2) were generated and validated. Membrane preparations from the cell lines were investigated using SSM-based electrophysiology. Baculovirus transfected insect cells (HighFive and Mimic Sf9) were also tested with the same assay but yielded less than optimal results. The assays were validated by the determination of substrate affinities and inhibition by standard inhibitors. The study demonstrates the suitability of the SSM-based electrophysiological OCT assay for rapid and automatic screening of drug candidates.
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Sarna A, Luchters SMF, Geibel S, Kaai S, Munyao P, Shikely KS, Mandaliya K, van Dam J, Temmerman M. Sexual risk behaviour and HAART: a comparative study of HIV-infected persons on HAART and on preventive therapy in Kenya. Int J STD AIDS 2008; 19:85-9. [PMID: 18334059 DOI: 10.1258/ijsa.2007.007097] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Unprotected sex (UPS) among persons receiving highly active antiretroviral therapy (HAART) remains a concern because of the risk of HIV-transmission. A cross-sectional study comparing the sexual risk behaviour of 179 people living with HIV/AIDS (PLHA) receiving HAART with that of 143 PLHA receiving preventive therapy (PT) with cotrimoxazole/isoniazid was conducted in Mombasa, Kenya. Forty-five percent of all participants were sexually active in the last six months. Participants receiving PT were more likely to report > or =2 partners (13% vs.1%; P = 0.006). Participants receiving PT reported more UPS with regular partners (odds ratio [OR]: 3.9; 95% confidence interval [CI]: 1.8-8.4) and also more sexually transmitted infections (STI) symptoms (OR: 1.7; 95% CI: 1.0-2.8; P = 0.059). More than 40% of all participants did not know the HIV-status of regular partners. Therefore, HAART was not associated with increased sexual risk behaviours though considerable risk of HIV-transmission remains. HIV-care services need to emphasize partner testing and consistent condom use with all partners.
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Affiliation(s)
- A Sarna
- Population Council, India Habitat Centre, New Delhi, India.
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Tang CP, Chen T, Velten R, Jeschke P, Ebbinghaus-Kintscher U, Geibel S, Ye Y. Alkaloids from stems and leaves of Stemona japonica and their insecticidal activities. J Nat Prod 2008; 71:112-116. [PMID: 18163592 DOI: 10.1021/np070427k] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Five new alkaloids, 6beta-hydroxystemofoline (1), 16-hydroxystemofoline (2), neostemofoline (3), protostemodiol (4), and 13-demethoxy-11(S*),12(R*)-dihydroprotostemonine (5), along with 10 known alkaloids, were isolated from stems and leaves of Stemona japonica. Their structures were elucidated by 1D and 2D NMR and other spectroscopic studies. The insecticidal activity of the agonist 16-hydroxystemofoline (2) and antagonist 13-demethoxy-11(S*),12(R*)-dihydroprotostemonine (5) was demonstrated by electrophysiological in vitro tests on the insect nicotinic acetylcholine receptor and by in vivo screenings against relevant agricultural insect pests.
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Affiliation(s)
- Chun-Ping Tang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, People's Republic of China
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Esu-Williams E, Schenk KD, Geibel S, Motsepe J, Zulu A, Bweupe P, Weiss E. 'We are no longer called club members but caregivers': Involving youth in HIV and AIDS caregiving in rural Zambia. AIDS Care 2007; 18:888-94. [PMID: 17012077 DOI: 10.1080/09540120500308170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This study assessed the strategy of building young people's capacity to provide care and support to people living with HIV and AIDS in rural Zambia. Members of youth anti-AIDS clubs in schools and communities were trained as adjunct caregivers using a locally developed curriculum that allowed them to explore and challenge gendered notions of caregiving and emphasized networking with existing resources. Results show that caregiving increased among males (47% to 82%) and females (41% to 78%). Both sexes provided similar caregiving services, including help with household chores and personal care tasks. Youth also undertook activities with children to decrease their isolation, help them stay in school, and reach additional services. While clients and caregivers reported positive aspects of the programme, both reported frustration with the youths' inability to meet material needs. This study demonstrates that trained youth already involved in anti-AIDS efforts can meet a range of care needs and be valuable assets to their community. It also highlights the importance of communicating clearly what youth can and cannot do, ongoing monitoring and support of youth caregivers, and involving community leaders to give youth credibility and access to local resources.
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Affiliation(s)
- E Esu-Williams
- Population Council/Horizons Program, Johannesburg, South Africa
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Geibel S, Flores-Herr N, Licher T, Vollert H. Establishment of cell-free electrophysiology for ion transporters: application for pharmacological profiling. ACTA ACUST UNITED AC 2006; 11:262-8. [PMID: 16490768 DOI: 10.1177/1087057105285110] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ion transporters are emerging targets of increasing importance to the pharmaceutical industry because of their relevance to a wide range of numerous indications of cardiovascular, metabolic, and inflammatory diseases. However, traditional ion transporter assay technologies using radioactive or fluorescent ligands and substrates or manual patch clamping suffer from several problems: limited sensitivity and robustness, significant numbers of false positives and false negatives, and cost. The authors describe a novel method for the measurement of ion transporters using cell-free electrophysiology based on the SURFE (2) R (surface electrogenic event reader) technology platform. The main advantages of the method described here are high sensitivity and simple handling. Material for assays is mainly a simple membrane preparation, which can be stored over weeks and months. Thus, the application of the method does not depend on a permanently running cell-culture lab. The application of the technology itself uses a bench-top system and chips loaded with membrane fragments. The SURFE (2) R technology was used to establish an Na+/Ca2+-exchanger assay. The assay performance, as judged by the Z' value of 0.73 and the signal-to-background ratio of 7.6, suggests that this is a reliable and robust assay. The authors compared the technology with patch-clamp experiments: The measurement of activity of 17 different inhibitors and the determination of an IC (50)value indicated a good correlation between SURFE (2) R technology and patch clamp results. Using the SURFE (2) R technology, results were obtained with 20 times higher throughput and required less-qualified personnel compared with manual patch clamping.
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Affiliation(s)
- Sven Geibel
- Lead Identification Technologies, New Assay Technologies, Sanofi-Aventis Pharma Deutschland GmbH, Frankfurt am Main, Germany
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Koenderink JB, Geibel S, Grabsch E, De Pont JJHHM, Bamberg E, Friedrich T. Electrophysiological analysis of the mutated Na,K-ATPase cation binding pocket. J Biol Chem 2003; 278:51213-22. [PMID: 14532287 DOI: 10.1074/jbc.m306384200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Na,K-ATPase mediates net electrogenic transport by extruding three Na+ ions and importing two K+ ions across the plasma membrane during each reaction cycle. We mutated putative cation coordinating amino acids in transmembrane hairpin M5-M6 of rat Na,K-ATPase: Asp776 (Gln, Asp, Ala), Glu779 (Asp, Gln, Ala), Asp804 (Glu, Asn, Ala), and Asp808 (Glu, Asn, Ala). Electrogenic cation transport properties of these 12 mutants were analyzed in two-electrode voltage-clamp experiments on Xenopus laevis oocytes by measuring the voltage dependence of K+-stimulated stationary currents and pre-steady-state currents under electrogenic Na+/Na+ exchange conditions. Whereas mutants D804N, D804A, and D808A hardly showed any Na+/K+ pump currents, the other constructs could be classified according to the [K+] and voltage dependence of their stationary currents; mutants N776A and E779Q behaved similarly to the wild-type enzyme. Mutants E779D, E779A, D808E, and D808N had in common a decreased apparent affinity for extracellular K+. Mutants N776Q, N776D, and D804E showed large deviations from the wild-type behavior; the currents generated by mutant N776D showed weaker voltage dependence, and the current-voltage curves of mutants N776Q and D804E exhibited a negative slope. The apparent rate constants determined from transient Na+/Na+ exchange currents are rather voltage-independent and at potentials above -60 mV faster than the wild type. Thus, the characteristic voltage-dependent increase of the rate constants at hyperpolarizing potentials is almost absent in these mutants. Accordingly, dislocating the carboxamide or carboxyl group of Asn776 and Asp804, respectively, decreases the extracellular Na+ affinity.
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Affiliation(s)
- Jan B Koenderink
- Department of Biophysical Chemistry, Max-Planck-Institute of Biophysics, Marie-Curie-Strasse 15, D-60439 Frankfurt am Main, Germany.
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Abstract
Steady-state and pre-steady-state currents of Asn(776) mutants of Na,K-ATPase are presented. The stationary current generated by N776Q strongly depends on the membrane potential, but has a negative slope, opposite to that of the wild-type enzyme. The apparent rate constant of the reaction sequence E(1)P(Na(+)) <--> E(2)P + Na(+) of this mutant is rather independent of the membrane potential and is at resting and depolarizing membrane potential higher than that of the wild-type enzyme. Thus, the voltage-dependent increase of the rate coefficient of the wild type that is associated with extracellular Na(+) rebinding is almost absent in the N776Q mutant. These findings indicate that dislocating the carboxamide group of Asn(776) decreases the affinity of sodium at its extracellular binding site.
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Affiliation(s)
- Jan B Koenderink
- Department of Biophysical Chemistry, Max-Planck-Institute of Biophysics, Frankfurt am Main, Germany.
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Geibel S, Zimmermann D, Zifarelli G, Becker A, Koenderink JB, Hu YK, Kaplan JH, Friedrich T, Bamberg E. Conformational dynamics of Na+/K+- and H+/K+-ATPase probed by voltage clamp fluorometry. Ann N Y Acad Sci 2003; 986:31-8. [PMID: 12763772 DOI: 10.1111/j.1749-6632.2003.tb07136.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We used the method of site-directed fluorescence labeling in combination with voltage-clamp fluorometry for time-resolved recording of localized conformational transitions of the Na(+)/K(+)- and H(+)/K(+)-ATPase. Therefore, single cysteine mutations were introduced into the extracellular TM5-TM6 loop of the sheep Na(+)/K(+)-ATPase alpha(1)-subunit devoid of other extracellular cysteines. Upon expression in Xenopus oocytes and covalent attachment of tetramethylrhodamine-maleimide (TMRM) as a reporter fluorophore, Cys-mutant N790C showed large fluorescence changes of up to 5% in response to extracellular K(+) that were completely abolished by ouabain. When voltage jumps were applied under Na(+)/Na(+)-exchange conditions, we observed fluorescence changes that paralleled the transient currents originating from the E(1)P<-->E(2)P transition. These fluorescence changes were also completely inhibited by ouabain, as were the voltage jump-induced transient currents. Transient fluorescence changes could also be measured as a function of increasing K(+) concentrations, that is, under turnover conditions. As a result, the distribution between E(1) and E(2) states can be determined at any time and membrane potential. Very similar fluorescence signals were obtained for rat gastric H(+)/K(+)-ATPase upon expression in oocytes, when a single cysteine was introduced at a position homologous to N790 in Na(+)/K(+)-ATPase for attachment of the fluorophore. As to the high sequence similarity among P-type ATPases within the TM5 helix and the TM5-TM6 loop region, our results enable new means of kinetic investigation for these pumps under physiological conditions in living cells.
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Affiliation(s)
- Sven Geibel
- Max-Planck-Institute of Biophysics, Kennedyallee 70, D-60596 Frankfurt/M., Germany
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Abstract
The method of voltage clamp fluorometry combined with site-directed fluorescence labeling was used to detect local protein motions of the fully active Na(+)K(+)-ATPase in real time under physiological conditions. Because helix M5 extends from the cytoplasmic site of ATP hydrolysis into the cation binding region, we chose the extracellular M5-M6 loop of the sheep alpha(1)-subunit for the insertion of cysteine residues to identify reporter positions for conformational rearrangements during the catalytic cycle. After expression of the single cysteine mutants in Xenopus oocytes and covalent attachment of tetramethylrhodamine-6-maleimide, only mutant N790C reported molecular rearrangements of the M5-M6 loop by showing large, ouabain-sensitive fluorescence changes ( approximately 5%) on addition of extracellular K(+). When the enzyme was subjected to voltage jumps under Na(+)Na(+)-exchange conditions, we observed fluorescence changes that directly correlated to transient charge movements originating from the E(1)P-E(2)P transition of the transport cycle. The voltage jump-induced fluorescence changes and transient currents were abolished after replacement of Na(+) by tetraethylammonium or on addition of ouabain, showing that conformational flexibility is impaired under these conditions. Voltage-dependent fluorescence changes could also be observed in the presence of subsaturating K(+) concentrations. This allowed to monitor the time course of voltage-dependent relaxations into a new stationary distribution of states under turnover conditions, showing the acceleration of relaxation kinetics with increasing K(+) concentrations. As a result, the stationary distribution between E(1) and E(2) states and voltage-dependent relaxation times can be determined at any time and membrane potential under Na(+)Na(+) exchange as well as Na(+)K(+) turnover conditions.
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Affiliation(s)
- Sven Geibel
- Max Planck Institute of Biophysics, Kennedyallee 70, D-60596 Frankfurt, Germany
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Friedrich T, Geibel S, Kalmbach R, Chizhov I, Ataka K, Heberle J, Engelhard M, Bamberg E. Proteorhodopsin is a light-driven proton pump with variable vectoriality. J Mol Biol 2002; 321:821-38. [PMID: 12206764 DOI: 10.1016/s0022-2836(02)00696-4] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Proteorhodopsin, a homologue of archaeal bacteriorhodopsin (BR), belongs to a newly identified family of retinal proteins from marine bacteria, which could play an important role in the energy balance of the biosphere. We cloned the cDNA sequence of proteorhodopsin by chemical gene synthesis, expressed the protein in Escherichia coli cells, purified and reconstituted the protein in its functional active state. The photocycle characteristics were determined by time-resolved absorption and Fourier transform infrared (FT-IR) spectroscopy. The pH-dependence of the absorption spectrum indicates that the pK(a) of the primary acceptor of the Schiff base proton (Asp97) is 7.68. Generally, the photocycle of proteorhodopsin is similar to that of BR, although an L-like photocycle intermediate was not detectable. Whereas at pH>7 an M-like intermediate is formed upon illumination, at pH 5 no M-like intermediate could be detected. As the photocycle kinetics do not change between the acidic and alkaline state of proteorhodopsin, the only difference between these two forms is the protonation status of Asp97. This is corroborated by time-resolved FT-IR spectroscopy, which demonstrates that proton transfer from the retinal Schiff base to Asp97 is observed at alkaline pH, but the other vibrational changes are essentially pH-independent.After reconstitution into proteoliposomes, light-induced proton currents of proteorhodopsin were measured in a compound membrane system where proteoliposomes were adsorbed to planar lipid bilayers. Our results show that proteorhodopsin is a light-driven proton pump with characteristics similar to those of BR at alkaline pH. However, at acidic pH, the direction of proton pumping is inverted. Complementary experiments were carried out on proteorhodopsin expressed heterologously in Xenopus laevis oocytes under voltage clamp conditions. The following results were obtained. (1) At alkaline pH, proteorhodopsin mediates outwardly directed proton pumping like BR. (2) The direction of proton pumping can be inverted, when Asp97 is protonated. (3) The current can be inverted by changes of the polarity of the applied voltage. (4) The light intensity-dependence of the photocurrents leads to the conclusion that the alkaline form of proteorhodopsin shows efficient proton pumping after sequential excitation by two photons.
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Affiliation(s)
- Thomas Friedrich
- Max-Planck-Institute of Biophysics, Department of Biophysical Chemistry, Kennedyallee 70, D-60596 Frankfurt am Main, Germany
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Geibel S, Friedrich T, Ormos P, Wood PG, Nagel G, Bamberg E. The voltage-dependent proton pumping in bacteriorhodopsin is characterized by optoelectric behavior. Biophys J 2001; 81:2059-68. [PMID: 11566778 PMCID: PMC1301679 DOI: 10.1016/s0006-3495(01)75855-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The light-driven proton pump bacteriorhodopsin (bR) was functionally expressed in Xenopus laevis oocytes and in HEK-293 cells. The latter expression system allowed high time resolution of light-induced current signals. A detailed voltage clamp and patch clamp study was performed to investigate the DeltapH versus Deltapsi dependence of the pump current. The following results were obtained. The current voltage behavior of bR is linear in the measurable range between -160 mV and +60 mV. The pH dependence is less than expected from thermodynamic principles, i.e., one DeltapH unit produces a shift of the apparent reversal potential of 34 mV (and not 58 mV). The M(2)-BR decay shows a significant voltage dependence with time constants changing from 20 ms at +60 mV to 80 ms at -160 mV. The linear I-V curve can be reconstructed by this behavior. However, the slope of the decay rate shows a weaker voltage dependence than the stationary photocurrent, indicating that an additional process must be involved in the voltage dependence of the pump. A slowly decaying M intermediate (decay time > 100 ms) could already be detected at zero voltage by electrical and spectroscopic means. In effect, bR shows optoelectric behavior. The long-lived M can be transferred into the active photocycle by depolarizing voltage pulses. This is experimentally demonstrated by a distinct charge displacement. From the results we conclude that the transport cycle of bR branches via a long-lived M(1)* in a voltage-dependent manner into a nontransporting cycle, where the proton release and uptake occur on the extracellular side.
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Affiliation(s)
- S Geibel
- Max Planck Institut für Biophysik, D-60596 Frankfurt am Main, Germany
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Geibel S, Barth A, Amslinger S, Jung AH, Burzik C, Clarke RJ, Givens RS, Fendler K. P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP for the rapid activation of the Na(+),K(+)-ATPase. Biophys J 2000; 79:1346-57. [PMID: 10968997 PMCID: PMC1301029 DOI: 10.1016/s0006-3495(00)76387-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP (pHP-caged ATP) has been investigated for its application as a phototrigger for the rapid activation of electrogenic ion pumps. The yield of ATP after irradiation with a XeCl excimer laser (lambda = 308 nm) was determined at pH 6.0-7.5. For comparison, the photolytic yields of P(3)-[1-(2-nitrophenyl)]ethyl ATP (NPE-caged ATP) and P(3)-[1, 2-diphenyl-2-oxo]ethyl ATP (desyl-caged ATP) were also measured. It was shown that at lambda = 308 nm pHP-caged ATP is superior to the other caged ATP derivatives investigated in terms of yield of ATP after irradiation. Using time-resolved single-wavelength IR spectroscopy, we determined a lower limit of 10(6) s(-1) for the rate constant of release of ATP from pHP-caged ATP at pH 7.0. Like NPE-caged ATP, pHP-caged ATP and desyl-caged ATP bind to the Na(+), K(+)-ATPase and act as competitive inhibitors of ATPase function. Using pHP-caged ATP, we investigated the charge translocation kinetics of the Na(+),K(+)-ATPase at pH 6.2-7.4. The kinetic parameters obtained from the electrical measurements are compared to those obtained with a technique that does not require caged ATP, namely parallel stopped-flow experiments using the voltage-sensitive dye RH421. It is shown that the two techniques yield identical results, provided the inhibitory properties of the caged compound are taken into account. Our results demonstrate that under physiological (pH 7.0) and slightly basic (pH 7.5) or acidic (pH 6. 0) conditions, pHP-caged ATP is a rapid, effective, and biocompatible phototrigger for ATP-driven biological systems.
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Affiliation(s)
- S Geibel
- Max-Planck-Institut für Biophysik, D-60596 Frankfurt/Main, Germany
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