The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Virginie Lattard - One of the best experts on this subject based on the ideXlab platform.
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Adaptative evolution of the VKorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides
Ecology and Evolution, 2017Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Virginie LattardAbstract:Anticoagulant rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the vitamin K epoxide reductase (VKORC1), which is an enzyme encoded by the VKorc1 gene, involved in the recycling of vitamin K. Therefore, they prevent blood clotting. Numerous mutations of VKorc1 gene were reported in rodents, and some are involved in the resistant to rodenticides phenotype. Two hundred and sixty-six mice tails were received from 65 different locations in France. Coding sequences of VKorc1 gene were sequenced in order to detect mutations. Consequences of the observed mutations were evaluated by the use of recombinant VKORC1. More than 70% of mice presented VKorc1 mutations. Among these mice, 80% were homozygous. Contrary to brown rats for which only one predominant VKorc1 genotype was found in France, nine missense single mutations and four double mutations were observed in house mice. The single mutations lead to resistance to first-generation Antivitamin K (AVKs) only and are certainly associated with the use of these first-generation molecules by nonprofessionals for the control of mice populations. The double mutations, probably obtained by genetic recombination, lead to in vitro resistance to all AVKs. They must be regarded as an adaptive evolution to the current use of second-generation AVKs. The intensive use of first-generation anticoagulants probably allowed the selection of a high diversity of mutations, which maKes possible the genetic recombination and consequently provoKes the emergence of the more resistant mutated VKorc1 described to date.
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Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus VKorc1.
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Stéphane Besse, Etienne Benoit, Claire Hascoët, Khedidja Dorani, Lionel Legros, Virginie LattardAbstract:BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the VKorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the VKorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive VKorc1spr-introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry
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evidence of a target resistance to Antivitamin K rodenticides in the roof rat rattus rattus identification and characterisation of a novel y25f mutation in the vKorc1 gene
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Audrey Chapuzet, Nolan Chatron, Luba Tchertanov, Virginie LattardAbstract:BACKGROUND In spite of intensive use of bromadiolone, rodent control was inefficient on a farm infested by rats in Zaragoza, Spain. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to Antivitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS From rats trapped on the farm, cytochrome b and VKorc1 genes were amplified by PCR and sequenced in order to identify species and detect potential VKorc1 mutations. VKORC1-deduced amino acid sequences were thus expressed in Pichia pastoris, and inhibition constants towards various rodenticides were determined. The ten rats trapped on the farm were all identified as R. rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the VKorc1 gene, leading to p.Y25F mutation. This mutation led to increased apparent inhibition constants towards various rodenticides, probably caused by a partial loss of helical structure of TM4. CONCLUSION The p.Y25F mutation detected in the VKorc1 gene in R. rattus trapped on the Spanish farm is associated with the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to Antivitamin K anticoagulants in R. rattus. © 2015 Society of Chemical Industry
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Development of an ecofriendly anticoagulant rodenticide based on the stereochemistry of difenacoum
Drug Metabolism and Disposition, 2016Co-Authors: Marlène Damin-pernik, Florence Popowycz, Stéphane Besse, Isabelle Fourel, Etienne Benoit, Bernadette Espana, Hervé Caruel, Virginie LattardAbstract:Difenacoum, an Antivitamin K anticoagulant, has been widely used as rodenticide to manage populations of rodents. Difenacoum belongs to the second generation of anticoagulant, and, as all the molecules belonging to the second generation of anticoagulant, difenacoum is often involved in primary poisonings of domestic animals and secondary poisonings of wildlife by feeding contaminated rodents. To develop a new and ecofriendly difenacoum, we explored in this study the differences in properties between diastereomers of difenacoum. Indeed, the currently commercial difenacoum is a mixture of 57% of cis-isomers and 43% of transisomers. Cis- and trans-isomers were thus purified on a C18 column, and their respective pharmacoKinetic properties and their efficiency to inhibit the coagulation of rodents were explored. Tissue persistence of trans-isomers was shown to be shorter than that of cis-isomers with a half-life fivefold shorter. Efficiency to inhibit the vitamin K epoxide reductase activity involved in the coagulation process was shown to be similar between cis- and trans-isomers. The use of trans-isomers of difenacoum allowed to drastically reduce difenacoum residues in liver and other tissues of rodents when the rodent is moribund. Therefore, secondary poisonings of wildlife should be decreased by the use of difenacoum largely enriched in trans-isomers.
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comparative inhibitory effect of prenylated coumarins ferulenol and ferprenin contained in the poisonous chemotype of ferula communis on mammal liver microsomal vKorc1 activity
Phytochemistry, 2015Co-Authors: Mariesophie Louvet, Gilbert Gault, Manon Boulven, Florence Popowycz, Sébastien Lefebvre, Virginie Lattard, Stéphane Besse, Etienne Benoit, Denis GrancherAbstract:Two distinguishable chemotypes of Ferula communis have been described: the 'nonpoisonous' chemotype, containing as main constituents the daucane esters; and the 'poisonous' chemotype containing prenylated coumarins, such as ferulenol and ferprenin. Ferulenol and ferprenin are 4-oxygenated molecules such as dicoumarol and warfarin, the first developed Antivitamin K molecules. Antivitamin K molecules specifically inhibit VKORC1, an enzyme essential for recycling vitamin K. This latest is involved in the activation of clotting factors II, VII, IX, X. The inhibiting effect of ferulenol on VKORC1 was shown in rat, but not for species exposed to F. communis while in vivo studies suggest differences between animal susceptibility to ferulenol. The inhibiting effect of ferprenin on VKORC1 was never demonstrated. The aim of this study was to compare the inhibiting effect of both compounds on VKORC1 of different species exposed to F. communis. Vitamin K epoxide activity was evaluated for each species from liver microsomes and inhibiting effect of ferulenol and ferprenin was characterized. Ferulenol and ferprenin were shown to be able to inhibit VKORC1 from all analyzed species. Nevertheless, susceptibility to ferulenol and ferprenin presented differences between species, suggesting a different susceptibility to 'poisonous' chemotypes of F. communis.
Etienne Benoit - One of the best experts on this subject based on the ideXlab platform.
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Adaptative evolution of the VKorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides
Ecology and Evolution, 2017Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Virginie LattardAbstract:Anticoagulant rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the vitamin K epoxide reductase (VKORC1), which is an enzyme encoded by the VKorc1 gene, involved in the recycling of vitamin K. Therefore, they prevent blood clotting. Numerous mutations of VKorc1 gene were reported in rodents, and some are involved in the resistant to rodenticides phenotype. Two hundred and sixty-six mice tails were received from 65 different locations in France. Coding sequences of VKorc1 gene were sequenced in order to detect mutations. Consequences of the observed mutations were evaluated by the use of recombinant VKORC1. More than 70% of mice presented VKorc1 mutations. Among these mice, 80% were homozygous. Contrary to brown rats for which only one predominant VKorc1 genotype was found in France, nine missense single mutations and four double mutations were observed in house mice. The single mutations lead to resistance to first-generation Antivitamin K (AVKs) only and are certainly associated with the use of these first-generation molecules by nonprofessionals for the control of mice populations. The double mutations, probably obtained by genetic recombination, lead to in vitro resistance to all AVKs. They must be regarded as an adaptive evolution to the current use of second-generation AVKs. The intensive use of first-generation anticoagulants probably allowed the selection of a high diversity of mutations, which maKes possible the genetic recombination and consequently provoKes the emergence of the more resistant mutated VKorc1 described to date.
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Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus VKorc1.
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Stéphane Besse, Etienne Benoit, Claire Hascoët, Khedidja Dorani, Lionel Legros, Virginie LattardAbstract:BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the VKorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the VKorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive VKorc1spr-introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry
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evidence of a target resistance to Antivitamin K rodenticides in the roof rat rattus rattus identification and characterisation of a novel y25f mutation in the vKorc1 gene
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Audrey Chapuzet, Nolan Chatron, Luba Tchertanov, Virginie LattardAbstract:BACKGROUND In spite of intensive use of bromadiolone, rodent control was inefficient on a farm infested by rats in Zaragoza, Spain. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to Antivitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS From rats trapped on the farm, cytochrome b and VKorc1 genes were amplified by PCR and sequenced in order to identify species and detect potential VKorc1 mutations. VKORC1-deduced amino acid sequences were thus expressed in Pichia pastoris, and inhibition constants towards various rodenticides were determined. The ten rats trapped on the farm were all identified as R. rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the VKorc1 gene, leading to p.Y25F mutation. This mutation led to increased apparent inhibition constants towards various rodenticides, probably caused by a partial loss of helical structure of TM4. CONCLUSION The p.Y25F mutation detected in the VKorc1 gene in R. rattus trapped on the Spanish farm is associated with the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to Antivitamin K anticoagulants in R. rattus. © 2015 Society of Chemical Industry
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Development of an ecofriendly anticoagulant rodenticide based on the stereochemistry of difenacoum
Drug Metabolism and Disposition, 2016Co-Authors: Marlène Damin-pernik, Florence Popowycz, Stéphane Besse, Isabelle Fourel, Etienne Benoit, Bernadette Espana, Hervé Caruel, Virginie LattardAbstract:Difenacoum, an Antivitamin K anticoagulant, has been widely used as rodenticide to manage populations of rodents. Difenacoum belongs to the second generation of anticoagulant, and, as all the molecules belonging to the second generation of anticoagulant, difenacoum is often involved in primary poisonings of domestic animals and secondary poisonings of wildlife by feeding contaminated rodents. To develop a new and ecofriendly difenacoum, we explored in this study the differences in properties between diastereomers of difenacoum. Indeed, the currently commercial difenacoum is a mixture of 57% of cis-isomers and 43% of transisomers. Cis- and trans-isomers were thus purified on a C18 column, and their respective pharmacoKinetic properties and their efficiency to inhibit the coagulation of rodents were explored. Tissue persistence of trans-isomers was shown to be shorter than that of cis-isomers with a half-life fivefold shorter. Efficiency to inhibit the vitamin K epoxide reductase activity involved in the coagulation process was shown to be similar between cis- and trans-isomers. The use of trans-isomers of difenacoum allowed to drastically reduce difenacoum residues in liver and other tissues of rodents when the rodent is moribund. Therefore, secondary poisonings of wildlife should be decreased by the use of difenacoum largely enriched in trans-isomers.
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comparative inhibitory effect of prenylated coumarins ferulenol and ferprenin contained in the poisonous chemotype of ferula communis on mammal liver microsomal vKorc1 activity
Phytochemistry, 2015Co-Authors: Mariesophie Louvet, Gilbert Gault, Manon Boulven, Florence Popowycz, Sébastien Lefebvre, Virginie Lattard, Stéphane Besse, Etienne Benoit, Denis GrancherAbstract:Two distinguishable chemotypes of Ferula communis have been described: the 'nonpoisonous' chemotype, containing as main constituents the daucane esters; and the 'poisonous' chemotype containing prenylated coumarins, such as ferulenol and ferprenin. Ferulenol and ferprenin are 4-oxygenated molecules such as dicoumarol and warfarin, the first developed Antivitamin K molecules. Antivitamin K molecules specifically inhibit VKORC1, an enzyme essential for recycling vitamin K. This latest is involved in the activation of clotting factors II, VII, IX, X. The inhibiting effect of ferulenol on VKORC1 was shown in rat, but not for species exposed to F. communis while in vivo studies suggest differences between animal susceptibility to ferulenol. The inhibiting effect of ferprenin on VKORC1 was never demonstrated. The aim of this study was to compare the inhibiting effect of both compounds on VKORC1 of different species exposed to F. communis. Vitamin K epoxide activity was evaluated for each species from liver microsomes and inhibiting effect of ferulenol and ferprenin was characterized. Ferulenol and ferprenin were shown to be able to inhibit VKORC1 from all analyzed species. Nevertheless, susceptibility to ferulenol and ferprenin presented differences between species, suggesting a different susceptibility to 'poisonous' chemotypes of F. communis.
Joffrey Goulois - One of the best experts on this subject based on the ideXlab platform.
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Adaptative evolution of the VKorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides
Ecology and Evolution, 2017Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Virginie LattardAbstract:Anticoagulant rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the vitamin K epoxide reductase (VKORC1), which is an enzyme encoded by the VKorc1 gene, involved in the recycling of vitamin K. Therefore, they prevent blood clotting. Numerous mutations of VKorc1 gene were reported in rodents, and some are involved in the resistant to rodenticides phenotype. Two hundred and sixty-six mice tails were received from 65 different locations in France. Coding sequences of VKorc1 gene were sequenced in order to detect mutations. Consequences of the observed mutations were evaluated by the use of recombinant VKORC1. More than 70% of mice presented VKorc1 mutations. Among these mice, 80% were homozygous. Contrary to brown rats for which only one predominant VKorc1 genotype was found in France, nine missense single mutations and four double mutations were observed in house mice. The single mutations lead to resistance to first-generation Antivitamin K (AVKs) only and are certainly associated with the use of these first-generation molecules by nonprofessionals for the control of mice populations. The double mutations, probably obtained by genetic recombination, lead to in vitro resistance to all AVKs. They must be regarded as an adaptive evolution to the current use of second-generation AVKs. The intensive use of first-generation anticoagulants probably allowed the selection of a high diversity of mutations, which maKes possible the genetic recombination and consequently provoKes the emergence of the more resistant mutated VKorc1 described to date.
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Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus VKorc1.
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Stéphane Besse, Etienne Benoit, Claire Hascoët, Khedidja Dorani, Lionel Legros, Virginie LattardAbstract:BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the VKorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the VKorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive VKorc1spr-introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry
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evidence of a target resistance to Antivitamin K rodenticides in the roof rat rattus rattus identification and characterisation of a novel y25f mutation in the vKorc1 gene
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Audrey Chapuzet, Nolan Chatron, Luba Tchertanov, Virginie LattardAbstract:BACKGROUND In spite of intensive use of bromadiolone, rodent control was inefficient on a farm infested by rats in Zaragoza, Spain. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to Antivitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS From rats trapped on the farm, cytochrome b and VKorc1 genes were amplified by PCR and sequenced in order to identify species and detect potential VKorc1 mutations. VKORC1-deduced amino acid sequences were thus expressed in Pichia pastoris, and inhibition constants towards various rodenticides were determined. The ten rats trapped on the farm were all identified as R. rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the VKorc1 gene, leading to p.Y25F mutation. This mutation led to increased apparent inhibition constants towards various rodenticides, probably caused by a partial loss of helical structure of TM4. CONCLUSION The p.Y25F mutation detected in the VKorc1 gene in R. rattus trapped on the Spanish farm is associated with the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to Antivitamin K anticoagulants in R. rattus. © 2015 Society of Chemical Industry
Lionel Legros - One of the best experts on this subject based on the ideXlab platform.
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Adaptative evolution of the VKorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides
Ecology and Evolution, 2017Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Virginie LattardAbstract:Anticoagulant rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the vitamin K epoxide reductase (VKORC1), which is an enzyme encoded by the VKorc1 gene, involved in the recycling of vitamin K. Therefore, they prevent blood clotting. Numerous mutations of VKorc1 gene were reported in rodents, and some are involved in the resistant to rodenticides phenotype. Two hundred and sixty-six mice tails were received from 65 different locations in France. Coding sequences of VKorc1 gene were sequenced in order to detect mutations. Consequences of the observed mutations were evaluated by the use of recombinant VKORC1. More than 70% of mice presented VKorc1 mutations. Among these mice, 80% were homozygous. Contrary to brown rats for which only one predominant VKorc1 genotype was found in France, nine missense single mutations and four double mutations were observed in house mice. The single mutations lead to resistance to first-generation Antivitamin K (AVKs) only and are certainly associated with the use of these first-generation molecules by nonprofessionals for the control of mice populations. The double mutations, probably obtained by genetic recombination, lead to in vitro resistance to all AVKs. They must be regarded as an adaptive evolution to the current use of second-generation AVKs. The intensive use of first-generation anticoagulants probably allowed the selection of a high diversity of mutations, which maKes possible the genetic recombination and consequently provoKes the emergence of the more resistant mutated VKorc1 described to date.
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Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus VKorc1.
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Stéphane Besse, Etienne Benoit, Claire Hascoët, Khedidja Dorani, Lionel Legros, Virginie LattardAbstract:BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the VKorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the VKorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive VKorc1spr-introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry
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evidence of a target resistance to Antivitamin K rodenticides in the roof rat rattus rattus identification and characterisation of a novel y25f mutation in the vKorc1 gene
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Etienne Benoit, Lionel Legros, Véronique Lambert, Audrey Chapuzet, Nolan Chatron, Luba Tchertanov, Virginie LattardAbstract:BACKGROUND In spite of intensive use of bromadiolone, rodent control was inefficient on a farm infested by rats in Zaragoza, Spain. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to Antivitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS From rats trapped on the farm, cytochrome b and VKorc1 genes were amplified by PCR and sequenced in order to identify species and detect potential VKorc1 mutations. VKORC1-deduced amino acid sequences were thus expressed in Pichia pastoris, and inhibition constants towards various rodenticides were determined. The ten rats trapped on the farm were all identified as R. rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the VKorc1 gene, leading to p.Y25F mutation. This mutation led to increased apparent inhibition constants towards various rodenticides, probably caused by a partial loss of helical structure of TM4. CONCLUSION The p.Y25F mutation detected in the VKorc1 gene in R. rattus trapped on the Spanish farm is associated with the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to Antivitamin K anticoagulants in R. rattus. © 2015 Society of Chemical Industry
Stéphane Besse - One of the best experts on this subject based on the ideXlab platform.
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Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus VKorc1.
Pest Management Science, 2016Co-Authors: Joffrey Goulois, Stéphane Besse, Etienne Benoit, Claire Hascoët, Khedidja Dorani, Lionel Legros, Virginie LattardAbstract:BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the VKorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the VKorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive VKorc1spr-introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry
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Development of an ecofriendly anticoagulant rodenticide based on the stereochemistry of difenacoum
Drug Metabolism and Disposition, 2016Co-Authors: Marlène Damin-pernik, Florence Popowycz, Stéphane Besse, Isabelle Fourel, Etienne Benoit, Bernadette Espana, Hervé Caruel, Virginie LattardAbstract:Difenacoum, an Antivitamin K anticoagulant, has been widely used as rodenticide to manage populations of rodents. Difenacoum belongs to the second generation of anticoagulant, and, as all the molecules belonging to the second generation of anticoagulant, difenacoum is often involved in primary poisonings of domestic animals and secondary poisonings of wildlife by feeding contaminated rodents. To develop a new and ecofriendly difenacoum, we explored in this study the differences in properties between diastereomers of difenacoum. Indeed, the currently commercial difenacoum is a mixture of 57% of cis-isomers and 43% of transisomers. Cis- and trans-isomers were thus purified on a C18 column, and their respective pharmacoKinetic properties and their efficiency to inhibit the coagulation of rodents were explored. Tissue persistence of trans-isomers was shown to be shorter than that of cis-isomers with a half-life fivefold shorter. Efficiency to inhibit the vitamin K epoxide reductase activity involved in the coagulation process was shown to be similar between cis- and trans-isomers. The use of trans-isomers of difenacoum allowed to drastically reduce difenacoum residues in liver and other tissues of rodents when the rodent is moribund. Therefore, secondary poisonings of wildlife should be decreased by the use of difenacoum largely enriched in trans-isomers.
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comparative inhibitory effect of prenylated coumarins ferulenol and ferprenin contained in the poisonous chemotype of ferula communis on mammal liver microsomal vKorc1 activity
Phytochemistry, 2015Co-Authors: Mariesophie Louvet, Gilbert Gault, Manon Boulven, Florence Popowycz, Sébastien Lefebvre, Virginie Lattard, Stéphane Besse, Etienne Benoit, Denis GrancherAbstract:Two distinguishable chemotypes of Ferula communis have been described: the 'nonpoisonous' chemotype, containing as main constituents the daucane esters; and the 'poisonous' chemotype containing prenylated coumarins, such as ferulenol and ferprenin. Ferulenol and ferprenin are 4-oxygenated molecules such as dicoumarol and warfarin, the first developed Antivitamin K molecules. Antivitamin K molecules specifically inhibit VKORC1, an enzyme essential for recycling vitamin K. This latest is involved in the activation of clotting factors II, VII, IX, X. The inhibiting effect of ferulenol on VKORC1 was shown in rat, but not for species exposed to F. communis while in vivo studies suggest differences between animal susceptibility to ferulenol. The inhibiting effect of ferprenin on VKORC1 was never demonstrated. The aim of this study was to compare the inhibiting effect of both compounds on VKORC1 of different species exposed to F. communis. Vitamin K epoxide activity was evaluated for each species from liver microsomes and inhibiting effect of ferulenol and ferprenin was characterized. Ferulenol and ferprenin were shown to be able to inhibit VKORC1 from all analyzed species. Nevertheless, susceptibility to ferulenol and ferprenin presented differences between species, suggesting a different susceptibility to 'poisonous' chemotypes of F. communis.