1
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Paichitrojjana A, Paichitrojjana A. Case Series of Demodicosis in Acne Vulgaris Patients. Clin Cosmet Investig Dermatol 2023; 16:3363-3368. [PMID: 38021431 PMCID: PMC10664713 DOI: 10.2147/ccid.s441581] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/14/2023] [Indexed: 12/01/2023]
Abstract
An abnormal density of Demodex mites can trigger many skin disorders known as demodicosis. Clinical manifestations of demodicosis may resemble other skin diseases and can coexist with other skin disorders, resulting in underdiagnosis and a more challenging diagnosis. Here, we report three cases of demodicosis in acne vulgaris patients. These case series have discussed their clinical features along with optimal strategies for diagnosis and treatment.
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Affiliation(s)
- Anon Paichitrojjana
- School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University, Bangkok, Thailand
| | - Anand Paichitrojjana
- Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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2
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Asahi M, Yamato K, Ozoe F, Ozoe Y. External amino acid residues of insect GABA receptor channels dictate the action of the isoxazoline ectoparasiticide fluralaner. PEST MANAGEMENT SCIENCE 2023; 79:4078-4082. [PMID: 37288963 DOI: 10.1002/ps.7606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/09/2023]
Abstract
BACKGROUND Fluralaner is the first isoxazoline ectoparasiticide developed to protect companion animals from fleas and ticks. Fluralaner primarily inhibits arthropod γ-aminobutyric acid receptors (GABARs), which are ligand-gated ion channels comprising five subunits arranged around the channel pore. We previously reported that the action site of fluralaner resides at the M1-M3 transmembrane interface between adjacent GABAR subunits. To investigate whether fluralaner interacts with the second transmembrane segment (M2) located deep in the interface, we generated four housefly RDL GABAR mutants with non-conservative amino acid substitutions in the M2 region. RESULTS Electrophysiological analysis of GABARs expressed in Xenopus oocytes indicated that S313A and S314A mutants exhibited fluralaner sensitivities similar to that of the wild type. M312S mutant exhibited approximately seven-fold lower sensitivity than that of the wild type. Notably, the N316L mutant was almost insensitive to fluralaner. CONCLUSION The findings of this study indicate that the conserved external amino acid residues of insect GABAR channels play a critical role in the antagonistic effect of fluralaner. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Miho Asahi
- Biological Research Laboratories, Nissan Chemical Corporation, Shiraoka, Saitama, Japan
| | - Kohei Yamato
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane, Japan
| | - Fumiyo Ozoe
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane, Japan
- Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane, Japan
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane, Japan
- Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane, Japan
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3
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Zhang Y, Huang Q, Sheng C, Liu G, Zhang K, Jia Z, Tang T, Mao X, Jones AK, Han Z, Zhao C. G3'MTMD3 in the insect GABA receptor subunit, RDL, confers resistance to broflanilide and fluralaner. PLoS Genet 2023; 19:e1010814. [PMID: 37384781 DOI: 10.1371/journal.pgen.1010814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Meta-diamides (e.g. broflanilide) and isoxazolines (e.g. fluralaner) are novel insecticides that target the resistant to dieldrin (RDL) subunit of insect γ-aminobutyric acid receptors (GABARs). In this study, we used in silico analysis to identify residues that are critical for the interaction between RDL and these insecticides. Substitution of glycine at the third position (G3') in the third transmembrane domain (TMD3) with methionine (G3'M TMD3), which is present in vertebrate GABARs, had the strongest effect on fluralaner binding. This was confirmed by expression of RDL from the rice stem borer, Chilo suppressalis (CsRDL) in oocytes of the African clawed frog, Xenopus laevis, where the G3'MTMD3 mutation almost abolished the antagonistic action of fluralaner. Subsequently, G3'MTMD3 was introduced into the Rdl gene of the fruit fly, Drosophila melanogaster, using the CRISPR/Cas9 system. Larvae of heterozygous lines bearing G3'MTMD3 did not show significant resistance to avermectin, fipronil, broflanilide, and fluralaner. However, larvae homozygous for G3'MTMD3 were highly resistant to broflanilide and fluralaner whilst still being sensitive to fipronil and avermectin. Also, homozygous lines showed severely impaired locomotivity and did not survive to the pupal stage, indicating a significant fitness cost associated with the G3'MTMD3. Moreover, the M3'GTMD3 in the mouse Mus musculus α1β2 GABAR increased sensitivity to fluralaner. Taken together, these results provide convincing in vitro and in vivo evidence for both broflanilide and fluralaner acting on the same amino acid site, as well as insights into potential mechanisms leading to target-site resistance to these insecticides. In addition, our findings could guide further modification of isoxazolines to achieve higher selectivity for the control of insect pests with minimal effects on mammals.
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Affiliation(s)
- Yichi Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Qiutang Huang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Chengwang Sheng
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Genyan Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Kexin Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Zhongqiang Jia
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, People's Republic of China
| | - Xin Mao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Zhaojun Han
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Chunqing Zhao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, People's Republic of China
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4
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Huang S, Ma H, Wang Z, Zhang P, Li S, Li Y, Liu A, Li Y, Liu Y, Wang Q. Design, Synthesis, and Insecticidal and Fungicidal Activities of Ether/Oxime-ether Containing Isoxazoline Derivatives. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:5107-5116. [PMID: 36947168 DOI: 10.1021/acs.jafc.2c08161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The existing agricultural insecticides have developed drug resistance from long-term use. Isoxazoline derivatives are new insecticides discovered in the 21st century. Because of their unique insecticidal mechanism, high selectivity, safety, and no significant cross resistance with the existing pesticides on the market, they have become a hot spot in the field of pesticide research. Herein, a series of novel isoxazoline derivatives containing ether and oxime-ether structures were designed and synthesized by a scaffold-hopping strategy using the pesticide fluralaner as a template structure. Through the investigation of insecticidal activity and the systematic structure-activity relationship, a series of compounds with high insecticidal activities were found, and compounds I-4, II-9, and II-13 with LC50 values of 0.00008-0.00036 mg/L against diamondback moth emerged as novel insecticide candidates. These compounds also exhibited broad spectrum fungicidal activities against 14 plant fungi. The current work provides a reference for the design of new isoxazoline compounds based on the scaffold-hopping strategy.
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Affiliation(s)
- Shisheng Huang
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin 300387, China
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Henan Ma
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Ziwen Wang
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin 300387, China
| | - Pengli Zhang
- Tianjin Ringpu Bio-technology Co., Ltd., Tianjin 300000, China
| | - Shoujun Li
- Tianjin Ringpu Bio-technology Co., Ltd., Tianjin 300000, China
| | - Yaling Li
- Tianjin Ringpu Bio-technology Co., Ltd., Tianjin 300000, China
| | - Ailing Liu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
- Tianjin Ringpu Bio-technology Co., Ltd., Tianjin 300000, China
| | - Yongqiang Li
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Yuxiu Liu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Qingmin Wang
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
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5
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Takano K, de Hayr L, Carver S, Harvey RJ, Mounsey KE. Pharmacokinetic and pharmacodynamic considerations for treating sarcoptic mange with cross-relevance to Australian wildlife. Int J Parasitol Drugs Drug Resist 2023; 21:97-113. [PMID: 36906936 PMCID: PMC10023865 DOI: 10.1016/j.ijpddr.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/15/2023] [Accepted: 02/20/2023] [Indexed: 03/07/2023]
Abstract
Sarcoptes scabiei is the microscopic burrowing mite responsible for sarcoptic mange, which is reported in approximately 150 mammalian species. In Australia, sarcoptic mange affects a number of native and introduced wildlife species, is particularly severe in bare-nosed wombats (Vombatus ursinus) and an emerging issue in koala and quenda. There are a variety of acaricides available for the treatment of sarcoptic mange which are generally effective in eliminating mites from humans and animals in captivity. In wild populations, effective treatment is challenging, and concerns exist regarding safety, efficacy and the potential emergence of acaricide resistance. There are risks where acaricides are used intensively or inadequately, which could adversely affect treatment success rates as well as animal welfare. While reviews on epidemiology, treatment strategies, and pathogenesis of sarcoptic mange in wildlife are available, there is currently no review evaluating the use of specific acaricides in the context of their pharmacokinetic and pharmacodynamic properties, and subsequent likelihood of emerging drug resistance, particularly for Australian wildlife. This review critically evaluates acaricides that have been utilised to treat sarcoptic mange in wildlife, including dosage forms and routes, pharmacokinetics, mode of action and efficacy. We also highlight the reports of resistance of S. scabiei to acaricides, including clinical and in vitro observations.
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Affiliation(s)
- Kotaro Takano
- School of Health, University of the Sunshine Coast, Maroochydore, Queensland, Australia; Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Lachlan de Hayr
- School of Health, University of the Sunshine Coast, Maroochydore, Queensland, Australia; Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Scott Carver
- Department of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Robert J Harvey
- School of Health, University of the Sunshine Coast, Maroochydore, Queensland, Australia; Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Kate E Mounsey
- School of Health, University of the Sunshine Coast, Maroochydore, Queensland, Australia; Sunshine Coast Health Institute, Birtinya, QLD, Australia.
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6
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Sun X, Hua W, Wang K, Song J, Zhu B, Gao X, Liang P. A novel V263I mutation in the glutamate-gated chloride channel of Plutella xylostella (L.) confers a high level of resistance to abamectin. Int J Biol Macromol 2023; 230:123389. [PMID: 36706876 DOI: 10.1016/j.ijbiomac.2023.123389] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
The frequent and extensive use of insecticides leads to the evolution of insecticide resistance, which has become one of the constraints on global agricultural production. Avermectins are microbial-derived insecticides that target a wide number of insect pests, including the diamondback moth Plutella xylostella, an important global pest of brassicaceous vegetables. However, field populations of P. xylostella have evolved serious resistance to avermectins, including abamectin, thereby threatening the efficiency of these insecticides. In this study, a novel valine to isoleucine mutation (V263I) was identified in the glutamate-gated chloride channel (GluCl) of field P. xylostella populations, which showed different levels of resistance to abamectin. Electrophysiological analysis revealed that the V263I mutation significantly reduced the sensitivity of PxGluCl to abamectin by 6.9-fold. Genome-modified Drosophila melanogaster carrying the V263I mutation exhibited 27.1-fold resistance to abamectin. Then, a knockin strain (V263I-KI) of P. xylostella expressing the homozygous V263I mutation was successfully constructed using the CRISPR/Cas9. The V263I-KI had high resistance to abamectin (106.3-fold), but significantly reduced fecundity. In this study, the function of V263I mutation in PxGluCl was verified for the first time. These findings provide a more comprehensive understanding of abamectin resistance mechanisms and lay the foundation for providing a new molecular detection method for abamectin resistance monitoring.
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Affiliation(s)
- Xi Sun
- Department of Entomology, China Agricultural University, Beijing 100193, China
| | - Wenjuan Hua
- Department of Entomology, China Agricultural University, Beijing 100193, China
| | - Kunkun Wang
- Department of Entomology, China Agricultural University, Beijing 100193, China
| | - Jiajia Song
- Department of Entomology, China Agricultural University, Beijing 100193, China
| | - Bin Zhu
- Department of Entomology, China Agricultural University, Beijing 100193, China.
| | - Xiwu Gao
- Department of Entomology, China Agricultural University, Beijing 100193, China
| | - Pei Liang
- Department of Entomology, China Agricultural University, Beijing 100193, China.
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7
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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 MANAGEMENT SCIENCE 2023; 79:183-193. [PMID: 36116012 DOI: 10.1002/ps.7187] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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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8
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Huang SS, Zhu BB, Wang KH, Yu M, Wang ZW, Li Y, Liu YX, Zhang PL, Li SJ, Li YL, Liu AL, Wang QM. Design, synthesis, and insecticidal and fungicidal activities of quaternary ammonium salt derivatives of a triazolyphenyl isoxazoline insecticide. PEST MANAGEMENT SCIENCE 2022; 78:2011-2021. [PMID: 35118797 DOI: 10.1002/ps.6824] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/27/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Insect pests seriously decrease the yield and quality of agricultural crops. Resistance to commonly used insecticides is increasingly undermining their effectiveness, and therefore the development of agents with novel modes of action is desirable. Isoxazolines are a new class of insecticides that act on γ-aminobutyric acid (GABA) gated chloride channels. In this work, we used the highly active 4-triazolyphenyl isoxazoline DP-9 as a parent structure to design and synthesize a series of quaternary ammonium salt (QAS) derivatives, and we systematically evaluated their insecticidal and antifungal activities. RESULTS Many of the synthesized QASs exhibit insecticidal activities equivalent to or higher than that of DP-9. In particular, compounds I-31 (93%, 0.00005 mg/L) and I-34 (80%, 0.00001 mg/L) showed insecticidal activities against diamondback moth larvae that were 2-10 times higher than those of fluralaner (70%, 0.0001 mg/L) and DP-9 (80%, 0.0001 mg/L), in addition to showing excellent activities against oriental armyworm, fall armyworm, cotton bollworm, corn borer, and mosquito larvae. Furthermore, all of the synthesized compounds also showed broad-spectrum fungicidal activities. CONCLUSION The insecticidal activities of QAS derivatives of DP-9 were the same as or better than the activity of DP-9. Compounds I-31 and I-34 showed better insecticidal activities against diamondback moth larvae than fluralaner and DP-9, and thus are promising new candidates for insecticide research.
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Affiliation(s)
- Shi-Sheng Huang
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Bin-Bing Zhu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Kai-Hua Wang
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Mo Yu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Zi-Wen Wang
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin, 300387, China
| | - Yongqiang Li
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Yu-Xiu Liu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Peng-Li Zhang
- Tianjin Ringpu Bio-technology Co., Ltd, Tianjin, 300000, China
| | - Shou-Jun Li
- Tianjin Ringpu Bio-technology Co., Ltd, Tianjin, 300000, China
| | - Ya-Ling Li
- Tianjin Ringpu Bio-technology Co., Ltd, Tianjin, 300000, China
| | - Ai-Ling Liu
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
- Tianjin Ringpu Bio-technology Co., Ltd, Tianjin, 300000, China
| | - Qing-Min Wang
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
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9
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Cens T, Chavanieu A, Bertaud A, Mokrane N, Estaran S, Roussel J, Ménard C, De Jesus Ferreira M, Guiramand J, Thibaud J, Cohen‐Solal C, Rousset M, Rolland V, Vignes M, Charnet P. Molecular Targets of Neurotoxic Insecticides in
Apis mellifera. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Thierry Cens
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Alain Chavanieu
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Anaïs Bertaud
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Nawfel Mokrane
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Sébastien Estaran
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Julien Roussel
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Claudine Ménard
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | | | - Janique Guiramand
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Jean‐Baptiste Thibaud
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Catherine Cohen‐Solal
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Matthieu Rousset
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Valérie Rolland
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Michel Vignes
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Pierre Charnet
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
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10
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Farooq S, Ngaini Z. Synthesis of Benzalacetophenone Based Isoxazoline and Isoxazole Derivatives. CURR ORG CHEM 2022. [DOI: 10.2174/1385272826666220408120350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract:
The demand for natural product based drugs with less cost and efficient procedures has become a challenge to researchers. Benzalacetophenone is a natural product based species that is modified into numerous heterocyclic compounds including isoxazoline and isoxazole derivatives. The utility of isoxazoline and oxazole derivatives has been increased for the synthesis of the new and effective chemical entities to serve medicinal chemistry in the past few years. Isoxazoline and isoxazole are fascinating classes of heterocyclic compounds, which belong to N- and O-heterocycles, and are widely used as precursors for the development of drugs. This review highlights the recent work for the synthesis of mono and bis isoxazoline and isoxazole derivatives using stable benzalacetophenone and functionalization of isoxazoline and isoxazole, along with the prevailing biological properties.
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Affiliation(s)
- Saba Farooq
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Zainab Ngaini
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
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11
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Paichitrojjana A. Demodicosis Imitating Acne Vulgaris: A Case Report. Clin Cosmet Investig Dermatol 2022; 15:497-501. [PMID: 35340734 PMCID: PMC8942344 DOI: 10.2147/ccid.s358000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/10/2022] [Indexed: 11/23/2022]
Abstract
Demodicosis is caused by Demodex mite infestation and can present with a variety of clinical manifestations, including pityriasis folliculorum type, rosacea-like type, folliculitis-like type and perioral dermatitis-like type. Therefore, this skin condition is often misdiagnosed or underdiagnosed. This report presents a 19-year-old woman with a history of pityriasis folliculorum type demodicosis and successful treatment with oral ivermectin. After one year of remission, the patient began to develop a dry, itchy rash on her face for one month before multiple small edematous papules and pustules gradually appeared on both cheeks. The patient was first diagnosed as acne vulgaris and treated with doxycycline for 2 weeks, but the clinical symptoms did not show any signs of improvement. After reassessment based on clinical presentation and laboratory examination that found multiple Demodex mites from pustules and rash on both cheeks, the patient was diagnosed with folliculitis-like type demodicosis. However, this patient still had a very good response to oral ivermectin and metronidazole gel, and all clinical symptoms disappeared within 4 weeks after treatment. This is a case report of demodicosis imitating acne vulgaris and the first report demonstrating a change in clinical manifestations of demodicosis from pityriasis folliculorum type to folliculitis-like type.
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Affiliation(s)
- Anon Paichitrojjana
- School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University, Bangkok, 10110, Thailand
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12
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Paichitrojjana A. Demodex: the worst enemies are the ones that used to be friends. Dermatol Reports 2022; 14:9339. [PMID: 36199896 PMCID: PMC9527693 DOI: 10.4081/dr.2022.9339] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 08/23/2021] [Indexed: 12/02/2022] Open
Abstract
Demodex mites are common ectoparasites of the human pilosebaceous units. Most adults are infested with Demodex mites without clinical symptoms. Demodex mite will only become a pathogenic organism when there is an abnormal increase in the number of Demodex mite density. This situation happens when the equilibrium between Demodex mites, skin microenvironment and human immunity system changes. Demodex infestation can cause multiple skin disorders, which are grouped under the term demodicosis or demodicidosis. Clinical manifestations of demodicosis can mimic other known skin diseases such as folliculitis, rosacea, perioral dermatitis, which is why it is often misdiagnosed. Diagnosis criteria consists of relevant correlation of suspected clinical skin lesions, confirmed by the presence of abnormal proliferation of Demodex mites and by clinical cure after acaricidal treatment together with normalization of Demodex mite density. Dermatologists should be aware that demodicosis is not an uncommon skin disease, and there are still many unknowns about it that should be researched further.
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13
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Kono M, Ozoe F, Asahi M, Ozoe Y. State-dependent inhibition of GABA receptor channels by the ectoparasiticide fluralaner. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 181:105008. [PMID: 35082031 DOI: 10.1016/j.pestbp.2021.105008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/15/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
γ-Aminobutyric acid (GABA) receptors (GABARs) are ligand-gated Cl- channels, which cause an influx of Cl- that inhibits excitation in postsynaptic cells upon activation. GABARs are important targets for drugs and pest control chemicals. We previously reported that the isoxazoline ectoparasiticide fluralaner inhibits GABA-induced currents in housefly (Musca domestica) GABARs by binding to the putative binding site in the transmembrane subunit interface. In the present study, we investigated whether fluralaner inhibits the GABA response in the GABAR activated state, the resting state, or both, using two-electrode voltage clamp electrophysiology protocols. We found that inhibition progresses over time to steady-state levels by repeated short applications of GABA during fluralaner perfusion. The GABA response was not impaired by fluralaner treatment in the GABAR resting state. However, once inhibited, the GABA response was not restored by repeated applications of GABA. These findings suggest that fluralaner might reach the binding site of the activated conformation of GABARs in a stepwise fashion and tightly bind to it.
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Affiliation(s)
- Miku Kono
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Fumiyo Ozoe
- Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Miho Asahi
- Biological Research Laboratories, Nissan Chemical Corporation, Shiraoka, Saitama 349-0294, Japan
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane 690-8504, Japan; Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane 690-8504, Japan.
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14
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Zhan EL, Wang Y, Jiang J, Jia ZQ, Tang T, Song ZJ, Han ZJ, Zhao CQ. Influence of three insecticides targeting GABA receptor on fall armyworm Spodoptera frugiperda: Analyses from individual, biochemical and molecular levels. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 179:104973. [PMID: 34802523 DOI: 10.1016/j.pestbp.2021.104973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/07/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
The fall armyworm (FAW) Spodoptera frugiperda (Lepidoptera: Noctuidae) is a severe agricultural pest, which has invaded into China in 2019 and caused heavy damage to maize. The γ-aminobutyric acid receptor (GABAR)-targeted insecticides including broflanilide, fluralaner and fipronil exhibit high toxicity towards lepidopteran pests. However, whether they could be used for control of FAW and their possible mode of action in FAW remain unclear. In this study, broflanilide, fluralaner and fipronil exhibited high oral toxicity in FAW larvae with median lethal dose (LD50) values of 0.677, 0.711, and 23.577 mg kg-1 (active ingredient/ artificial food), respectively. In the electrophysiological assay, fluralaner and fipronil could strongly inhibit GABA-induced currents of homomeric FAW resistance to dieldrin 1 (RDL1) receptor with median inhibitory concentration (IC50) values of 5.018 nM (95% confidence interval (CI) 2.864-8.789) and 8.595 nM (95% CI 5.105-14.47), respectively, whereas broflanilide could not. In addition, the cytochrome P450 (P450), glutathione-S-transferase (GST) and carboxylesterase (CarE) activities were positively response to broflanilide, P450 and GST to fluralaner, and GST and CarE to fipronil, respectively, compared with those of control. In conclusion, we firstly reported a notable insecticidal activity of three representative GABAR-targeted insecticides to FAW in vivo, and in vitro using electrophysiological assay. The GST is the primary detoxification enzyme for three tested insecticides. Our results would guide the rotational use of GABAR-targeted insecticides in field.
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Affiliation(s)
- En-Ling Zhan
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Ying Wang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Jie Jiang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Zhong-Qiang Jia
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha 410125, PR China
| | - Zi-Jiao Song
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Zhao-Jun Han
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Chun-Qing Zhao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
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15
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Ozoe Y. Ion channels and G protein-coupled receptors as targets for invertebrate pest control: from past challenges to practical insecticides. Biosci Biotechnol Biochem 2021; 85:1563-1571. [PMID: 33988673 DOI: 10.1093/bbb/zbab089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/29/2021] [Indexed: 01/12/2023]
Abstract
In the late 1970s, we discovered that toxic bicyclic phosphates inhibit the generation of miniature inhibitory junction potentials, implying their antagonism of γ-aminobutyric acid (GABA) receptors (GABARs; GABA-gated chloride channels). This unique mode of action provided a strong incentive for our research on GABARs in later years. Furthermore, minor structural changes conferred insect GABAR selectivity to this class of compounds, convincing us of the possibility of GABARs as targets for insecticides. Forty years later, third-generation insecticides acting as allosteric modulator antagonists at a distinctive site of action in insect GABARs were developed. G protein-coupled receptors (GPCRs) are also promising targets for pest control. We characterized phenolamine receptors functionally and pharmacologically. Of the tested receptors, β-adrenergic-like octopamine receptors were revealed to be the most sensitive to the acaricide/insecticide amitraz. Given the presence of multiple sites of action, ion channels and GPCRs remain potential targets for invertebrate pest control.
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Affiliation(s)
- Yoshihisa Ozoe
- Faculty of Life and Environmental Sciences, Shimane University, Matsue, Shimane, Japan.,Interdisciplinary Institute for Science Research, Head Office for Research and Academic Information, Shimane University, Matsue, Shimane, Japan
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16
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Xue W, Mermans C, Papapostolou KM, Lamprousi M, Christou IK, Inak E, Douris V, Vontas J, Dermauw W, Van Leeuwen T. Untangling a Gordian knot: the role of a GluCl3 I321T mutation in abamectin resistance in Tetranychus urticae. PEST MANAGEMENT SCIENCE 2021; 77:1581-1593. [PMID: 33283957 DOI: 10.1002/ps.6215] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/03/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND The cys-loop ligand-gated ion channels, including the glutamate-gated chloride channel (GluCl) and GABA-gated chloride channel (Rdl) are important targets for drugs and pesticides. The macrocyclic lactone abamectin primarily targets GluCl and is commonly used to control the spider mite Tetranychus urticae, an economically important crop pest. However, abamectin resistance has been reported for multiple T. urticae populations worldwide, and in several cases was associated with the mutations G314D in GluCl1 and G326E in GluCl3. Recently, an additional I321T mutation in GluCl3 was identified in several abamectin resistant T. urticae field populations. Here, we aim to functionally validate this mutation and determine its phenotypic strength. RESULTS The GluCl3 I321T mutation was introgressed into a T. urticae susceptible background by marker-assisted backcrossing, revealing contrasting results in phenotypic strength, ranging from almost none to 50-fold. Next, we used CRISPR-Cas9 to introduce I321T, G314D and G326E in the orthologous Drosophila GluCl. Genome modified flies expressing GluCl I321T were threefold less susceptible to abamectin, while CRISPRed GluCl G314D and G326E flies were lethal. Last, functional analysis in Xenopus oocytes revealed that the I321T mutation might reduce GluCl3 sensitivity to abamectin, but also suggested that all three T. urticae Rdls are affected by abamectin. CONCLUSION Three different techniques were used to characterize the role of I321T in GluCl3 in abamectin resistance and, combining all results, our analysis suggests that the I321T mutation has a complex role in abamectin resistance. Given the reported subtle effect, additional synergistic factors in resistance warrant more investigation. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Wenxin Xue
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Catherine Mermans
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Kyriaki-Maria Papapostolou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Heraklion, Greece
- Department of Biology, University of Crete, Heraklion, Greece
| | - Mantha Lamprousi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Heraklion, Greece
- Department of Biology, University of Crete, Heraklion, Greece
| | - Iason-Konstantinos Christou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Heraklion, Greece
- Department of Biology, University of Crete, Heraklion, Greece
| | - Emre Inak
- Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
| | - Vassilis Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Heraklion, Greece
- Department of Biological Applications and Technology, University of Ioannina, Ioannina, Greece
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Heraklion, Greece
- Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, Athens, Greece
| | - Wannes Dermauw
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Thomas Van Leeuwen
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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17
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The molecular targets of ivermectin and lotilaner in the human louse Pediculus humanus humanus: New prospects for the treatment of pediculosis. PLoS Pathog 2021; 17:e1008863. [PMID: 33600484 PMCID: PMC7891696 DOI: 10.1371/journal.ppat.1008863] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/04/2021] [Indexed: 11/19/2022] Open
Abstract
Control of infestation by cosmopolitan lice (Pediculus humanus) is increasingly difficult due to the transmission of parasites resistant to pediculicides. However, since the targets for pediculicides have no been identified in human lice so far, their mechanisms of action remain largely unknown. The macrocyclic lactone ivermectin is active against a broad range of insects including human lice. Isoxazolines are a new chemical class exhibiting a strong insecticidal potential. They preferentially act on the γ-aminobutyric acid (GABA) receptor made of the resistant to dieldrin (RDL) subunit and, to a lesser extent on glutamate-gated chloride channels (GluCls) in some species. Here, we addressed the pediculicidal potential of isoxazolines and deciphered the molecular targets of ivermectin and the ectoparasiticide lotilaner in the human body louse species Pediculus humanus humanus. Using toxicity bioassays, we showed that fipronil, ivermectin and lotilaner are efficient pediculicides on adult lice. The RDL (Phh-RDL) and GluCl (Phh-GluCl) subunits were cloned and characterized by two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes. Phh-RDL and Phh-GluCl formed functional homomeric receptors respectively gated by GABA and L-glutamate with EC50 values of 16.0 μM and 9.3 μM. Importantly, ivermectin displayed a super agonist action on Phh-GluCl, whereas Phh-RDL receptors were weakly affected. Reversally, lotilaner strongly inhibited the GABA-evoked currents in Phh-RDL with an IC50 value of 40.7 nM, whereas it had no effect on Phh-GluCl. We report here for the first time the insecticidal activity of isoxazolines on human ectoparasites and reveal the mode of action of ivermectin and lotilaner on GluCl and RDL channels from human lice. These results emphasize an expected extension of the use of the isoxazoline drug class as new pediculicidal agents to tackle resistant-louse infestations in humans. Human cosmopolitan lice are responsible for pediculosis, which represent a significant public health concern. Resistant lice against insecticides and lack of safety of the treatments for human and environment is a growing issue worldwide. Here we investigated the efficacy on lice of the classical macrocyclic lactone drug, ivermectin, and of the isoxazoline drug, lotilaner. This study was done to decipher their mode of action at the molecular and functional levels in order to propose new strategies to control lice infestation. Our bioassay results indicate that ivermectin and lotilaner were potent at killing human adult lice, with lotilaner showing a higher efficacy than ivermectin. Furthermore, we identified and pharmacologically characterized the first glutamate- and GABA-gated chloride channels ever described in human lice yet. Mechanistically, our molecular biology and electrophysiology findings demonstrate that ivermectin acted preferentially at glutamate channels, while lotilaner specifically targeted GABA channels. These results provide new insights in the understanding of the insecticide mode of action and highlight the potential of isoxazolines as a new alternative for the treatment of human lice.
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18
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Xue W, Snoeck S, Njiru C, Inak E, Dermauw W, Van Leeuwen T. Geographical distribution and molecular insights into abamectin and milbemectin cross-resistance in European field populations of Tetranychus urticae. PEST MANAGEMENT SCIENCE 2020; 76:2569-2581. [PMID: 32237053 DOI: 10.1002/ps.5831] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/23/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Milbemectin and abamectin are frequently used to control the spider mite Tetranychus urticae. The development of abamectin resistance in this major pest has become an increasing problem worldwide, potentially compromising the use of milbemectin. In this study, a large collection of European field populations was screened for milbemectin and abamectin resistance, and both target-site and metabolic (cross-)resistance mechanisms were investigated. RESULTS High to very high levels of abamectin resistance were found in one third of all populations, while milbemectin resistance levels were low for most populations. The occurrence of well-known target-site resistance mutations in glutamate-gated chloride channels (G314D in GluCl1 and G326E in GluCl3) was documented in the most resistant populations. However, a new mutation, I321T in GluCl3, was also uncovered in three resistant populations, while a V327G and L329F mutation was found in GluCl3 of one resistant population. A differential gene-expression analysis revealed the overexpression of detoxification genes, more specifically cytochrome P450 monooxygenase (P450) and UDP-glycosyltransferase (UGT) genes. Multiple UGTs were functionally expressed, and their capability to glycosylate abamectin and milbemectin, was tested and confirmed. CONCLUSIONS We found a clear correlation between abamectin and milbemectin resistance in European T. urticae populations, but as milbemectin resistance levels were low, the observed cross-resistance is probably not of operational importance. The presence of target-site resistance mutations in GluCl genes was confirmed in most but not all resistant populations. Gene-expression analysis and functional characterization of P450s and UGTs suggests that also metabolic abamectin resistance mechanisms are common in European T. urticae populations. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Wenxin Xue
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Simon Snoeck
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Christine Njiru
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Emre Inak
- Department of Plant Protection, Faculty of Agriculture, Ankara University, Diskapi, Ankara, Turkey
| | - Wannes Dermauw
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium
| | - Thomas Van Leeuwen
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium
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19
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Palmieri V, Dodds WJ, Morgan J, Carney E, Fritsche HA, Jeffrey J, Bullock R, Kimball JP. Survey of canine use and safety of isoxazoline parasiticides. Vet Med Sci 2020; 6:933-945. [PMID: 32485788 PMCID: PMC7738705 DOI: 10.1002/vms3.285] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 04/06/2020] [Accepted: 04/25/2020] [Indexed: 11/17/2022] Open
Abstract
A veterinarian and pet owner survey (Project Jake) examined the use and safety of isoxazoline parasiticides given to dogs. Data were received during August 1–31, 2018 from a total of 2,751 survey responses. Forty‐two percent (1,157) reported no flea treatment or adverse events (AE), while 58% (1594) had been treated with some parasiticide for flea control, and of those that received a parasiticide, the majority, or 83% (1,325), received an isooxazoline. When any flea treatment was given, AE were reported for 66.6% of respondents, with no apparent AE noted for 36.1%. Project Jake findings were compared to a retrospective analysis of publicly available Food and Drug Administration (FDA) and European Medicines Agency (EMA) reported AE. The number of total AE reported to FDA and EMA were comparable, although a 7 to 10 times higher occurrence of death and seizures was reported from the EMA or from outside the United States (US). Serious AE responses for death, seizures and neurological effects reported in our survey were higher than the FDA but moderately lower than the EMA reports. These sizable global data sets combined with this pre‐ and post‐parasiticide administration survey indicated that isoxazoline neurotoxicity was not flea‐ and tick‐specific. Post‐marketing serious AE were much higher than in Investigational New Drug (IND) submissions. Although the labels have recently been updated, dogs, cats and their caregivers remain impacted by their use. These aggregate data reports support the need for continued cross‐species studies and critical review of product labelling by regulatory agencies and manufacturers.
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Affiliation(s)
| | | | - Judy Morgan
- Dr. Judy Morgan's Naturally Healthy Pets, Woodstown, NJ, USA
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20
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Foley R, Kelly P, Gatault S, Powell F. Demodex: a skin resident in man and his best friend. J Eur Acad Dermatol Venereol 2020; 35:62-72. [PMID: 32294279 DOI: 10.1111/jdv.16461] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/28/2020] [Indexed: 12/20/2022]
Abstract
Demodex mites are microscopic arachnids found in the normal skin of many mammals. In humans, it is well established that Demodex mite density is higher in patients with the skin condition rosacea, and treatment with acaricidal agents is effective in resolving symptoms. However, pathophysiology of rosacea is complex and multifactorial. In dogs, demodicosis is a significant veterinary issue, particularly the generalized form of the disease which can be fatal if untreated. In each species, clinical and molecular studies have shown that the host's immunological interactions with Demodex mites are an important, but not fully understood, aspect of how Demodex can live in the skin either as a harmless commensal organism or as a pathogenic agent. This review outlines the role of Demodex mites in humans and dogs, considering morphology, prevalence, symptoms, diagnosis, histology treatment and pathogenesis.
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Affiliation(s)
- R Foley
- UCD Charles Institute of Dermatology, University College Dublin, Dublin, Ireland
| | - P Kelly
- UCD Charles Institute of Dermatology, University College Dublin, Dublin, Ireland.,UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - S Gatault
- UCD Charles Institute of Dermatology, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | - F Powell
- UCD Charles Institute of Dermatology, University College Dublin, Dublin, Ireland
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21
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Yamato K, Nakata Y, Takashima M, Ozoe F, Asahi M, Kobayashi M, Ozoe Y. Effects of intersubunit amino acid substitutions on GABA receptor sensitivity to the ectoparasiticide fluralaner. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 163:123-129. [PMID: 31973848 DOI: 10.1016/j.pestbp.2019.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/17/2019] [Accepted: 11/03/2019] [Indexed: 06/10/2023]
Abstract
The isoxazoline ectoparasiticide fluralaner exerts antiparasitic effects by inhibiting the function of γ-aminobutyric acid (GABA) receptors (GABARs). The present study was conducted to identify the amino acid residues that contribute to the high sensitivity of insect GABARs to fluralaner. We generated housefly (Musca domestica) GABARs with amino acid substitutions in the first through third α-helical transmembrane segments (TM1-TM3) of the RDL subunit using site-directed mutagenesis and examined the effects of the substitutions on the sensitivity of GABARs expressed in Xenopus oocytes to fluralaner using two-electrode voltage clamp electrophysiology. The Q271L substitution in TM1 caused a significant reduction in the sensitivity to fluralaner. Although the I274A and I274F substitutions in TM1 did not affect fluralaner sensitivity, the I274C substitution significantly enhanced the sensitivity to fluralaner. In contrast, the L278C substitution in TM1 reduced fluralaner sensitivity. Substitutions of Gly333 in TM3 led to substantial reductions in the sensitivity to fluralaner. These findings indicate that Gln271, Ile274, Leu278, and Gly333, which are situated in the outer half of the transmembrane subunit interface, are closely related to the antagonism of GABARs by fluralaner.
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Affiliation(s)
- Kohei Yamato
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Yunosuke Nakata
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Madoka Takashima
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Fumiyo Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Miho Asahi
- Biological Research Laboratories, Nissan Chemical Corporation, Shiraoka, Saitama 349-0294, Japan
| | - Masaki Kobayashi
- Biological Research Laboratories, Nissan Chemical Corporation, Shiraoka, Saitama 349-0294, Japan
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan.
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22
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Li R, Pan X, Wang Q, Tao Y, Chen Z, Jiang D, Wu C, Dong F, Xu J, Liu X, Wu X, Zheng Y. Development of S-Fluxametamide for Bioactivity Improvement and Risk Reduction: Systemic Evaluation of the Novel Insecticide Fluxametamide at the Enantiomeric Level. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:13657-13665. [PMID: 31684725 DOI: 10.1021/acs.est.9b03697] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Increasing numbers of novel pesticides have been applied in agriculture. However, traditional evaluation of pesticides does not distinguish between their enantiomers, which may lead to inaccurate results. In this study, systematic research on the chiral insecticide fluxametamide was conducted at the enantiomeric level. The methods for enantioseparation and semipreparative separation of fluxametamide enantiomers were developed. The optical rotation and absolute configuration of two enantiomers were determined, and their stability was verified in solvents and soils. Enantioselective bioactivities against four target pests (Plutella xylostella, Spodoptera exigua, Aphis gossypii, and Tetranychus cinnabarinus) were tested. Acute toxicities of fluxametamide enantiomers toward honeybees were also evaluated. S-(+)-Isomer exhibited 52.1-304.4 times and 2.5-3.7 times higher bioactivity than R-(-)-isomer and rac-fluxametamide, respectively. Meanwhile, rac-fluxametamide was more toxic than S/R-isomer, and S-(+)-isomer showed >30-fold higher acute toxicity than R-(-)-isomer. Molecular docking studies were performed with γ-aminobutyric acid receptor (GABAR) to monitor the mechanism of stereoselective bioactivity. The better Grid score of S-(+)-fluxametamide (-60.12 kcal/mol) than R-(-)-enantiomer (-56.59 kcal/mol) indicated higher bioactivity of S-(+)-isomer than of R-(-)-isomer. The dissipation of fluxametamide in cabbage, Chinese cabbage, and soil was nonenantioselective under field conditions. Development of S-(+)-fluxametamide could maintain the high-efficacy and low-risk properties, which should attract attention of producers, applicators, and managers of pesticides.
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Affiliation(s)
- Runan Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Xinglu Pan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Qinqin Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Yan Tao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Zenglong Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents , Institute of Zoology, Chinese Academy of Sciences , Beijing 100101 , P. R. China
| | - Duoduo Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Chi Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Fengshou Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Jun Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Xingang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Xiaohu Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
| | - Yongquan Zheng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests , Institute of Plant Protection, Chinese Academy of Agricultural Sciences , Beijing 100193 , P. R. China
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Sheng CW, Huang QT, Liu GY, Ren XX, Jiang J, Jia ZQ, Han ZJ, Zhao CQ. Neurotoxicity and mode of action of fluralaner on honeybee Apis mellifera L. PEST MANAGEMENT SCIENCE 2019; 75:2901-2909. [PMID: 31081291 DOI: 10.1002/ps.5483] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Fluralaner, a novel pesticide that targets the γ-aminobutyric acid (GABA) receptor (GABAR) subunit of resistant to dieldrin (RDL), exhibits strong potential to be an insecticide to control agricultural insect pests. However, the risk and action of fluralaner to economic insects, e.g., honeybee Apis mellifera Linnaeus, remains unclear. RESULTS In this study, both oral and contact toxicity of fluralaner to honeybee were found to be 0.13 μg adult-1 . Abamectin, dieldrin, ethiprole, α-endosulfan, fipronil and fluralaner strongly inhibited the GABA-induced current in A. mellifera RDL (AmRDL), expressed in Xenopus laevis oocytes, with median inhibitory concentration (IC50 ) values of 7.99, 868.1, 27.10, 412.0, 11.21 and 13.59 nM, respectively. The binding free energy and electrophysiological response of AmRDL and insecticides were opposite. The correlation values between toxicity (to A. mellifera) and binding free energy/electrophysiological inhibition (to AmRDL) were at a moderate level. CONCLUSION In conclusion, we report for the first time the notable risk of fluralaner to honeybee in vivo and compared the actions of GABAR-targeted insecticides on the AmRDL receptor. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Cheng-Wang Sheng
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qiu-Tang Huang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Gen-Yan Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, 430205, China
| | - Xue-Xiang Ren
- Institute of Plant Protection and Agro-Products Safety, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Jie Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhong-Qiang Jia
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhao-Jun Han
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chun-Qing Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
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Gaens D, Rummel C, Schmidt M, Hamann M, Geyer J. Suspected neurological toxicity after oral application of fluralaner (Bravecto®) in a Kooikerhondje dog. BMC Vet Res 2019; 15:283. [PMID: 31391054 PMCID: PMC6686215 DOI: 10.1186/s12917-019-2016-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/18/2019] [Indexed: 11/10/2022] Open
Abstract
Background Although the new isoxazoline drug fluralaner (Bravecto®) is generally well tolerated in dogs, adverse drug reactions involving neurological dysfunction occurred in individual dogs. However, most of these cases are documented inadequately and none of them is reported and discussed in the literature. As isoxazoline drugs target neuronal chloride channels with a clear preference for invertebrates, they are considered to have a good safety profile. However, pharmacodynamic effects in the nervous system of vertebrates cannot be ruled out completely. Case presentation A seven-month-old female Kooikerhondje dog was treated with Bravecto® at the recommended dose. About 24 h after administration, the dog exhibited signs of neurological toxicity, including generalized ataxia, myoclonic jerks, tremor of head and body, muscle twitching and oral dysphagia. All symptoms were transient and the dog fully recovered without any treatment after 10 h. Conclusion This case report describes transient occurrence of neurological dysfunction after administration of Bravecto®. It may help to better classify adverse drug reactions after application of isoxazoline drugs and documents a good prognosis even after occurrence of severe neurological dysfunction in the present case. Electronic supplementary material The online version of this article (10.1186/s12917-019-2016-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniela Gaens
- Institute of Pharmacology and Toxicology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Martin Schmidt
- Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Melanie Hamann
- Institute of Pharmacology and Toxicology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany
| | - Joachim Geyer
- Institute of Pharmacology and Toxicology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392, Giessen, Germany.
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Liu G, Li H, Shi J, Wang W, Furuta K, Liu D, Zhao C, Ozoe F, Ju X, Ozoe Y. 4-Aryl-5-carbamoyl-3-isoxazolols as competitive antagonists of insect GABA receptors: Synthesis, biological activity, and molecular docking studies. Bioorg Med Chem 2018; 27:416-424. [PMID: 30579800 DOI: 10.1016/j.bmc.2018.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/09/2018] [Accepted: 12/11/2018] [Indexed: 12/01/2022]
Abstract
Competitive antagonists (CAs) of ionotropic GABA receptors (GABARs) reportedly exhibit insecticidal activity and have potential for development as novel insecticides for overcoming emerging resistance to traditional GABAR-targeting insecticides. Our previous studies demonstrated that 4,5-disubstituted 3-isoxazolols or 3-isothiazolols are an important class of insect GABAR CAs. In the present study, we synthesized a series of 4-aryl-5-carbamoyl-3-isoxazolols and examined their antagonism of insect GABARs expressed in Xenopus oocytes. Several of these 3-isoxazolols exhibited potent antagonistic activities against housefly and common cutworm GABARs, with IC50 values in the low-micromolar range in both receptors. 4-(3-Amino-4-methylphenyl)-5-carbamoyl-3-isoxazolol (3u) displayed the highest antagonism, with IC50 values of 2.0 and 0.9 μM in housefly and common cutworm GABARs, respectively. Most of the synthesized 3-isoxazolols showed moderate larvicidal activities against common cutworms, with more than 50% mortality at 100 μg/g. These results indicate that 4-monocyclic aryl-5-carbamoyl-3-isoxazolol is a promising scaffold for insect GABAR CA discovery and provide important information for the design and development of GABAR-targeting insecticides with a novel mode of action.
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Affiliation(s)
- Genyan Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, PR China.
| | - Huaguang Li
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, PR China
| | - Jiaying Shi
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, PR China
| | - Wenjie Wang
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, PR China
| | - Kenjiro Furuta
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Di Liu
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Chunqing Zhao
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Fumiyo Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
| | - Xiulian Ju
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, PR China
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan.
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26
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Asahi M, Kobayashi M, Kagami T, Nakahira K, Furukawa Y, Ozoe Y. Fluxametamide: A novel isoxazoline insecticide that acts via distinctive antagonism of insect ligand-gated chloride channels. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2018; 151:67-72. [PMID: 30704715 DOI: 10.1016/j.pestbp.2018.02.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/18/2018] [Accepted: 02/05/2018] [Indexed: 06/09/2023]
Abstract
Fluxametamide is a novel wide-spectrum insecticide that was discovered and synthesized by Nissan Chemical Industries, Ltd. To identify the mode of action of fluxametamide, we first performed [3H]4'-ethynyl-4-n-propylbicycloorthobenzoate (EBOB) binding assays. Fluxametamide potently inhibited the specific binding of [3H]EBOB to housefly-head membranes, suggesting that fluxametamide affects insect γ-aminobutyric acid (GABA)-gated chloride channels (GABACls). Next, the antagonism of housefly GABACls and glutamate-gated chloride channels (GluCls) was examined using the two-electrode voltage clamp (TEVC) method. Fluxametamide inhibited agonist responses in both ion channels expressed in Xenopus oocytes in the nanomolar range, indicating that this insecticide is a ligand-gated chloride channel (LGCC) antagonist. The insecticidal and LGCC antagonist potencies of fluxametamide against fipronil-susceptible and fipronil-resistant strains of small brown planthoppers and two-spotted spider mites, which are insensitive to fipronil, were evaluated. Fluxametamide exhibited similar levels of both activities in these fipronil-susceptible and fipronil-resistant arthropod pests. These data indicate that fluxametamide exerts distinctive antagonism of arthropod GABACls by binding to a site different from those for existing antagonists. In contrast to its profound actions on the arthropod LGCCs, the antagonistic activity of fluxametamide against rat GABACls and human glycine-gated chloride channels was nearly insignificant, suggesting that fluxametamide has high target-site selectivity for arthropods over mammals. Overall, fluxametamide is a new type of LGCC antagonist insecticide with excellent safety for mammals at the target-site level.
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Affiliation(s)
- Miho Asahi
- Biological Research Laboratories, Nissan Chemical Industries, Ltd., Saitama 349-0294, Japan
| | - Masaki Kobayashi
- Biological Research Laboratories, Nissan Chemical Industries, Ltd., Saitama 349-0294, Japan
| | - Takahiro Kagami
- Biological Research Laboratories, Nissan Chemical Industries, Ltd., Saitama 349-0294, Japan
| | - Kunimitsu Nakahira
- Biological Research Laboratories, Nissan Chemical Industries, Ltd., Saitama 349-0294, Japan
| | - Yuki Furukawa
- Chemical Research Laboratories, Nissan Chemical Industries, Ltd., Chiba 274-8507, Japan
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan.
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27
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Sheng CW, Jia ZQ, Ozoe Y, Huang QT, Han ZJ, Zhao CQ. Molecular cloning, spatiotemporal and functional expression of GABA receptor subunits RDL1 and RDL2 of the rice stem borer Chilo suppressalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 94:18-27. [PMID: 29408355 DOI: 10.1016/j.ibmb.2018.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/19/2018] [Accepted: 01/22/2018] [Indexed: 06/07/2023]
Abstract
Insect γ-aminobutyric acid (GABA) receptor (GABAR) is one of the major targets of insecticides. In the present study, cDNAs (CsRDL1A and CsRDL2S) encoding the two isoforms of RDL subunits were cloned from the rice stem borer Chilo suppressalis. Transcripts of both genes demonstrated similar expression patterns in different tissues and developmental stages, although CsRDL2S was ∼2-fold more abundant than CsRDL1A throughout all development stages. To investigate the function of channels formed by CsRDL subunits, both genes were expressed in Xenopus laevis oocytes singly or in combination in different ratios. Electrophysiological results using a two-electrode voltage clamp demonstrated that GABA activated currents in oocytes injected with both cRNAs. The EC50 value of GABA in activating currents was smaller in oocytes co-injected with CsRDL1A and CsRDL2S than in oocytes injected singly. The IC50 value of the insecticide fluralaner in inhibiting GABA responses was smaller in oocytes co-injected with different cRNAs than in oocytes injected singly. Co-injection also changed the potency of the insecticide dieldrin in oocytes injected singly. These findings suggested that heteromeric GABARs were formed by the co-injections of CsRDL1A and CsRDL2S in oocytes. Although the presence of Ser at the 2'-position in the second transmembrane segment was responsible for the insensitivity of GABARs to dieldrin, this amino acid did not affect the potencies of the insecticides fipronil and fluralaner. These results lead us to hypothesize that C. suppressalis may adapt to insecticide pressure by regulating the expression levels of CsRDL1A and CsRDL2S and the composition of both subunits in GABARs.
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Affiliation(s)
- Cheng-Wang Sheng
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Zhong-Qiang Jia
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, 690-8504, Japan
| | - Qiu-Tang Huang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Zhao-Jun Han
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Chun-Qing Zhao
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
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