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Mechanism behind Resistance against the Organophosphate Azamethiphos in Salmon Lice (Lepeophtheirus salmonis).

Kaur K, Helgesen KO, Bakke MJ, Horsberg TE - PLoS ONE (2015)

Bottom Line: We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains.The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos.The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos.

View Article: PubMed Central - PubMed

Affiliation: NMBU School of Veterinary Science, Sea Lice Research Centre, PO Box 8146 Dep., NO-0033 Oslo, Norway.

ABSTRACT
Acetylcholinesterase (AChE) is the primary target for organophosphates (OP). Several mutations have been reported in AChE to be associated with the reduced sensitivity against OP in various arthropods. However, to the best of our knowledge, no such reports are available for Lepeophtheirus salmonis. Hence, in the present study, we aimed to determine the association of AChE(s) gene(s) with resistance against OP. We screened the AChE genes (L. salmonis ace1a and ace1b) in two salmon lice populations: one sensitive (n=5) and the other resistant (n=5) for azamethiphos, a commonly used OP in salmon farming. The screening led to the identification of a missense mutation Phe362Tyr in L. salmonis ace1a, (corresponding to Phe331 in Torpedo californica AChE) in all the samples of the resistant population. We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains. The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos. The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos. Based on all these observations, the present study, for the first time, presents the mechanism of resistance in L. salmonis against azamethiphos. In addition, we developed a rapid diagnostic tool for the high throughput screening of Phe362Tyr mutation using High Resolution Melt analysis.

No MeSH data available.


Related in: MedlinePlus

Amino acid alignment.Alignment of the deduced amino acid sequence of both L. salmonis ace1a and ace1b in the region where the Phe362Tyr change was found, with previously published acetylcholinesterases (AChE) from other insects, arachnida and vertebrates (Insects: Liposcelis entomophila Lip_ent, Bemisia tabaci Bem_tab, Blattella germanica Bla_ger, Nephotettix cincticeps Nep_cin, Ctenocephalides felis Cte_fel, Culex pipiens Cul_pip, Chilo suppressalis Chi_sup, Apis mellifera Api_mel, Cimex lectularius Cim_lec, Bombyx mandarina Bom_man, Bombyx mori Bom_Mor, Leptinotarsa decemlineata Lep_dec, Drosophila melanogaster Dros, Musca domestica Mus_dom, Anopheles gambiae Ano_gam, Aedes albopictus Aed_alb, Culex quinquefasciatus Cul_qui, Arachnida: Tetranychus urticae Tet_urt, Rhipicephalus decoloratus Rhi_dec, Vertebrates: Torpedo californica Tor_cal, Homo sapiens Homosap. Phe362Tyr corresponds to Phe331 in Torpedo californica AChE. Phenylalanine at 331 is a highly conserved amino acid in the acetylcholinesterases among all species included. The Phe331Tyr change is boxed.
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pone.0124220.g003: Amino acid alignment.Alignment of the deduced amino acid sequence of both L. salmonis ace1a and ace1b in the region where the Phe362Tyr change was found, with previously published acetylcholinesterases (AChE) from other insects, arachnida and vertebrates (Insects: Liposcelis entomophila Lip_ent, Bemisia tabaci Bem_tab, Blattella germanica Bla_ger, Nephotettix cincticeps Nep_cin, Ctenocephalides felis Cte_fel, Culex pipiens Cul_pip, Chilo suppressalis Chi_sup, Apis mellifera Api_mel, Cimex lectularius Cim_lec, Bombyx mandarina Bom_man, Bombyx mori Bom_Mor, Leptinotarsa decemlineata Lep_dec, Drosophila melanogaster Dros, Musca domestica Mus_dom, Anopheles gambiae Ano_gam, Aedes albopictus Aed_alb, Culex quinquefasciatus Cul_qui, Arachnida: Tetranychus urticae Tet_urt, Rhipicephalus decoloratus Rhi_dec, Vertebrates: Torpedo californica Tor_cal, Homo sapiens Homosap. Phe362Tyr corresponds to Phe331 in Torpedo californica AChE. Phenylalanine at 331 is a highly conserved amino acid in the acetylcholinesterases among all species included. The Phe331Tyr change is boxed.

Mentions: The alignment of the L. salmonis AChE1a protein with 33 AChE amino acid sequences from other species revealed that the Phe362Tyr in ace1a is homologous to Phe331 of AChE in T.californica and is located in the acyl pocket neighboring the catalytic center in the active site gorge. It is a highly conserved residue among the species as evident from multiple sequence alignment (MSA) of AChEs from different species (Fig 3).


Mechanism behind Resistance against the Organophosphate Azamethiphos in Salmon Lice (Lepeophtheirus salmonis).

Kaur K, Helgesen KO, Bakke MJ, Horsberg TE - PLoS ONE (2015)

Amino acid alignment.Alignment of the deduced amino acid sequence of both L. salmonis ace1a and ace1b in the region where the Phe362Tyr change was found, with previously published acetylcholinesterases (AChE) from other insects, arachnida and vertebrates (Insects: Liposcelis entomophila Lip_ent, Bemisia tabaci Bem_tab, Blattella germanica Bla_ger, Nephotettix cincticeps Nep_cin, Ctenocephalides felis Cte_fel, Culex pipiens Cul_pip, Chilo suppressalis Chi_sup, Apis mellifera Api_mel, Cimex lectularius Cim_lec, Bombyx mandarina Bom_man, Bombyx mori Bom_Mor, Leptinotarsa decemlineata Lep_dec, Drosophila melanogaster Dros, Musca domestica Mus_dom, Anopheles gambiae Ano_gam, Aedes albopictus Aed_alb, Culex quinquefasciatus Cul_qui, Arachnida: Tetranychus urticae Tet_urt, Rhipicephalus decoloratus Rhi_dec, Vertebrates: Torpedo californica Tor_cal, Homo sapiens Homosap. Phe362Tyr corresponds to Phe331 in Torpedo californica AChE. Phenylalanine at 331 is a highly conserved amino acid in the acetylcholinesterases among all species included. The Phe331Tyr change is boxed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403986&req=5

pone.0124220.g003: Amino acid alignment.Alignment of the deduced amino acid sequence of both L. salmonis ace1a and ace1b in the region where the Phe362Tyr change was found, with previously published acetylcholinesterases (AChE) from other insects, arachnida and vertebrates (Insects: Liposcelis entomophila Lip_ent, Bemisia tabaci Bem_tab, Blattella germanica Bla_ger, Nephotettix cincticeps Nep_cin, Ctenocephalides felis Cte_fel, Culex pipiens Cul_pip, Chilo suppressalis Chi_sup, Apis mellifera Api_mel, Cimex lectularius Cim_lec, Bombyx mandarina Bom_man, Bombyx mori Bom_Mor, Leptinotarsa decemlineata Lep_dec, Drosophila melanogaster Dros, Musca domestica Mus_dom, Anopheles gambiae Ano_gam, Aedes albopictus Aed_alb, Culex quinquefasciatus Cul_qui, Arachnida: Tetranychus urticae Tet_urt, Rhipicephalus decoloratus Rhi_dec, Vertebrates: Torpedo californica Tor_cal, Homo sapiens Homosap. Phe362Tyr corresponds to Phe331 in Torpedo californica AChE. Phenylalanine at 331 is a highly conserved amino acid in the acetylcholinesterases among all species included. The Phe331Tyr change is boxed.
Mentions: The alignment of the L. salmonis AChE1a protein with 33 AChE amino acid sequences from other species revealed that the Phe362Tyr in ace1a is homologous to Phe331 of AChE in T.californica and is located in the acyl pocket neighboring the catalytic center in the active site gorge. It is a highly conserved residue among the species as evident from multiple sequence alignment (MSA) of AChEs from different species (Fig 3).

Bottom Line: We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains.The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos.The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos.

View Article: PubMed Central - PubMed

Affiliation: NMBU School of Veterinary Science, Sea Lice Research Centre, PO Box 8146 Dep., NO-0033 Oslo, Norway.

ABSTRACT
Acetylcholinesterase (AChE) is the primary target for organophosphates (OP). Several mutations have been reported in AChE to be associated with the reduced sensitivity against OP in various arthropods. However, to the best of our knowledge, no such reports are available for Lepeophtheirus salmonis. Hence, in the present study, we aimed to determine the association of AChE(s) gene(s) with resistance against OP. We screened the AChE genes (L. salmonis ace1a and ace1b) in two salmon lice populations: one sensitive (n=5) and the other resistant (n=5) for azamethiphos, a commonly used OP in salmon farming. The screening led to the identification of a missense mutation Phe362Tyr in L. salmonis ace1a, (corresponding to Phe331 in Torpedo californica AChE) in all the samples of the resistant population. We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains. The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos. The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos. Based on all these observations, the present study, for the first time, presents the mechanism of resistance in L. salmonis against azamethiphos. In addition, we developed a rapid diagnostic tool for the high throughput screening of Phe362Tyr mutation using High Resolution Melt analysis.

No MeSH data available.


Related in: MedlinePlus