Action of Phenylpyrazole Insecticides at the GABA-Gated Chloride Channel

Cole, Loretta M.; Nicholson, Russell A.; Casida, John E.

doi:10.1006/pest.1993.1035

Cited by 458 publications

(271 citation statements)

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“…5) It interferes with the function of g-aminobutyric acid (GABA)-gated channels; fipronil disrupts normal neuronal influx (e.g., passage of chloride ions) by targeting the GABA-gated chloride channel and, at sufficient doses, causes excessive neural excitation, severe paralysis, and death. 5,[13][14][15] Fipronil possesses a greater binding affinity for the GABA-regulated chloride channels of insects than mammalian GABA receptors. 16) …”

Section: Mode Of Actionmentioning

confidence: 99%

Environmental fate and toxicology of fipronil

Gunasekara¹,

Truong²,

et al. 2007

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Section: Mode Of Actionmentioning

confidence: 99%

Environmental fate and toxicology of fipronil

Gunasekara¹,

Truong²,

et al. 2007

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“…The high stability of these compounds may result in exposure to persistent residues in the environment, maintaining selection for the resistance allele in natural populations. Additionally, increasing household and field use of phenylpyrazole insecticides, which also target the insect RDL GABA receptor, may select for resistance alleles (9,44). In the early 1990s, the Ser 301 mutation frequency in populations of D. melanogaster in the United States was estimated at 1% (45).…”

mentioning

confidence: 99%

Gene duplication in the major insecticide target site,Rdl, inDrosophila melanogaster

Remnant

Good

Schmidt

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The Resistance to Dieldrin gene, Rdl, encodes a GABA-gated chloride channel subunit that is targeted by cyclodiene and phenylpyrazole insecticides. The gene was first characterized in Drosophila melanogaster by genetic mapping of resistance to the cyclodiene dieldrin. The 4,000-fold resistance observed was due to a single amino acid replacement, Ala 301 to Ser. The equivalent change was subsequently identified in Rdl orthologs of a large range of resistant insect species. Here, we report identification of a duplication at the Rdl locus in D. melanogaster. The 113-kb duplication contains one WT copy of Rdl and a second copy with two point mutations: an Ala 301 to Ser resistance mutation and Met 360 to Ile replacement. Individuals with this duplication exhibit intermediate dieldrin resistance compared with single copy Ser 301 homozygotes, reduced temperature sensitivity, and altered RNA editing associated with the resistant allele. Ectopic recombination between Roo transposable elements is involved in generating this genomic rearrangement. The duplication phenotypes were confirmed by construction of a transgenic, artificial duplication integrating the 55.7-kb Rdl locus with a Ser 301 change into an Ala 301 background. Gene duplications can contribute significantly to the evolution of insecticide resistance, most commonly by increasing the amount of gene product produced. Here however, duplication of the Rdl target site creates permanent heterozygosity, providing unique potential for adaptive mutations to accrue in one copy, without abolishing the endogenous role of an essential gene.T he single point mutation in the Resistance to dieldrin (Rdl) gene represents one of the most significant cases of target site resistance to an insecticide yet observed. Cyclodiene resistance was reported in 62% of insecticide resistant species in the 1980s, following widespread use of cyclodiene insecticides, including dieldrin, which started in the 1950s (1). The nature of the genetic target, Rdl, was discovered after dieldrin was discontinued because of the widespread evolution of resistance in many species. Rdl was first discovered in Drosophila melanogaster using a positional cloning approach. High homology to human GABA receptors confirmed it was the first insect ligand-gated chloride channel subunit identified (2-4). A point mutation in the chloride channel pore-lining domain, replacing alanine 301 with serine, was present in all resistant D. melanogaster strains (5). This mutation provided 4,000-fold resistance when homozygous and lower levels of resistance in heterozygotes (2, 6). The homologous mutation was subsequently found in a large number of cyclodiene-resistant species from many insect orders (7-9), as well as a glycine replacement at the homologous site in some resistant strains of Drosophila simulans and other species (5, 10, 11).Characterization of deficiency lines and inversions in D. melanogaster showed that Rdl is an essential gene (3). Thus, the Ala 301 to Ser or Gly mutation in Rdl exhibits unique properties, p...

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“…gamma aminobutyric acid (GABA receptors). Because of its different mode of action in comparison to classical insecticides fipronil also known as new generation insecticide [5].…”

Section: Introductionmentioning

confidence: 99%

Behaviour of Fipronil in Paddy Field Ecosystem

Duhan¹,

Kadian²,

Saroj³

2018

Asian J. Chem.

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Under normal environmental conditions, fipronil insecticide degrades into a number of metabolites like fipronil sulfone, sulfide, desulfinyl, etc. They can persist in environment for longer duration and can have adverse effect on soil, water bodies along-with persistence of residuals in edibles and other plant by-products like straw. In order to evaluate the impact of using fipronil in paddy field ecosystem and to provide basic information for its degradation behavior, a field experiment was done by applying the insecticide @ 56 and 112 g a.i./ha following standard agronomic conditions. Soil and water samples were collected periodically. Paddy grain, husk and straw samples were collected at harvest. Fipronil residues were analyzed by GC-MS tandem mass spectrometry. In soil, more than 48 % residues degraded in 7 days and reached below detectable limit after 49 days with half-life period of 9.29 and 10.13 days at two doses showing degradation rate to be biphasic with first order kinetics. In field water, residues reached below detectable limit on 49th day at single dose with half-life period of 14.71 days where as at double dose application, 91.52 % fipronil was found dissipated on 49th day after application with halflife period of 14.31 days. In rice grains, husk and straw, fipronil residues were found below MRL at single dose.

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Action of Phenylpyrazole Insecticides at the GABA-Gated Chloride Channel

Cited by 458 publications

References 0 publications

Environmental fate and toxicology of fipronil

Environmental fate and toxicology of fipronil

Gene duplication in the major insecticide target site,Rdl, inDrosophila melanogaster

Behaviour of Fipronil in Paddy Field Ecosystem

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