The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Blair D Siegfried - One of the best experts on this subject based on the ideXlab platform.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
Jeffrey J Swanson - One of the best experts on this subject based on the ideXlab platform.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
Linda M Field - One of the best experts on this subject based on the ideXlab platform.
-
a novel assay reveals the blockade of Esterases by piperonyl butoxide
Pest Management Science, 2008Co-Authors: Anna C Khot, Linda M Field, Georgina Bingham, Graham D MooresAbstract:BACKGROUND: Conventional in vitro assays sometimes fail to reveal Esterase inhibition by piperonyl butoxide (PBO), although synergism studies suggest loss of Esterase-mediated sequestration of insecticide does take place. A new in vitro assay has been devised that routinely reveals binding between PBO and these Esterases. RESULTS: The new ‘Esterase interference’ assay detects the blockade of resistance-associated Esterases in a species, Myzus persicae Sulzer, where this has not previously been seen. The assay also demonstrates directly the protective effect Esterases may confer to target sites of insecticides. CONCLUSION: The new assay reveals Esterase blockade by PBO and thus has the potential to be used as a high-throughput screening method for other potential synergists. Copyright © 2008 Society of Chemical Industry
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
Alan L. Devonshire - One of the best experts on this subject based on the ideXlab platform.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
-
amplification and methylation of an Esterase gene associated with insecticide resistance in greenbugs schizaphis graminum rondani homoptera aphididae
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Jeffrey J Swanson, Linda M Field, Alan L. Devonshire, Blair D SiegfriedAbstract:Abstract The greenbug aphid, Schizaphis graminum (Rondani) has developed resistance to organophosphorus insecticides by the over-production of Esterases that have been classified as Type I and Type II. The first twenty N-terminal amino acids of the Type I Esterase were determined and used to design an oligonucleotide, which in conjunction with an active site primer derived from conserved sequences of other insect Esterases and two internal primers specific for Esterases from another aphid species resulted in a 0.85 kb genomic DNA fragment from resistant greenbugs. This was extended by 5′ RACE which provided approximately 1.2 kb of the 5′ end of the Esterase gene. The 5′ DNA sequence corresponded to 19 of the 20 known amino acids of the Type I Esterase, with the last needing only a one base change (probably resulting from a PCR artifact). Furthermore, the sequence showed very close similarity to the amplified E4/FE4 Esterase genes of Myzus persicae (Sulzer). A comparison of sequences suggested that the S. graminum gene has introns in the same positions as the first two introns of E4/FE4, with the second intron being considerably larger in S. graminum. Probing of Southern blots with the 0.85 kb Esterase fragment showed that the gene encoding the Type I Esterase is amplified 4- to 8-fold in resistant S. graminum and that the amplified sequences contain 5-methylcytosine at MspI/HpaII sites, again in agreement with previous findings for M. persicae genes.
Anne Thierry - One of the best experts on this subject based on the ideXlab platform.
-
Identification of a secreted lipolytic Esterase in Propionibacterium freudenreichii
2011Co-Authors: Julien Dherbecourt, Hélène Falentin, Julien Jardin, Frédérique Barloy-hubler, Anne ThierryAbstract:Lipolysis plays an important role in the formation of cheese flavor. In Emmental cheese, the main part of lipolysis has been associated with the presence of Propionibacterium freudenreichii, a species used as a ripening culture. Our aim was to identify the most probable lipolytic Esterase(s) involved in cheese lipolysis by P. freudenreichii. Since cheese lipolysis mainly occurs during P. freudenreichii growth, we hypothesized that P. freudenreichii possesses secreted lipolytic Esterase(s). For 12 putative Esterase genes previously identified from the genome of P. freudenreichii CIRM1, the level of expression was quantified by real-time reverse transcriptase (RT)-PCR, and the subcellular localization of Esterases was predicted in silico. The Esterase activity in extracellular and intracellular extracts of P. freudenreichii was characterized by zymography, and the extracellular Esterases were identified by mass spectrometry. Finally, the best candidate was overexpressed in the same strain. All of the 12 genes encoding putative Esterases were expressed. Esterase PF#279 was predicted to be secreted in the medium, PF#774 to be surface exposed, and the 10 remaining putative Esterases to be intracellular. Zymography revealed that Esterase activities in culture supernatant differed from the ones detected in intracellular extracts. PF#279 was identified as the sole Esterase present in culture supernatant. Transformed P. freudenreichii CIRM1 clones overexpressing PF#279 showed 5 to 8 times more lipolytic activity on milk fat than the wild-type strain. Combining in silico, biochemical, and genetic approaches, we showed that PF#279 is the sole secreted Esterase in P. freudenreichii and is active on milk fat. Therefore, it is likely a key component in cheese lipolysis by P. freudenreichii.
-
Identification of a secreted lipolytic Esterase in Propionibacterium freudenreichii, a ripening process bacterium involved in emmental cheese lipolysis.
Applied and Environmental Microbiology, 2010Co-Authors: Julien Dherbecourt, Julien Jardin, Frédérique Barloy-hubler, M.-b. Maillard, F. Baglinière, Anne ThierryAbstract:Lipolysis plays an important role in the formation of cheese flavor. In Emmental cheese, the main part of lipolysis has been associated with the presence of Propionibacterium freudenreichii, a species used as a ripening culture. Our aim was to identify the most probable lipolytic Esterase(s) involved in cheese lipolysis by P. freudenreichii. Since cheese lipolysis mainly occurs during P. freudenreichii growth, we hypothesized that P. freudenreichii possesses secreted lipolytic Esterase(s). For 12 putative Esterase genes previously identified from the genome of P. freudenreichii CIRM1, the level of expression was quantified by real-time reverse transcriptase (RT)-PCR, and the subcellular localization of Esterases was predicted in silico. The Esterase activity in extracellular and intracellular extracts of P. freudenreichii was characterized by zymography, and the extracellular Esterases were identified by mass spectrometry. Finally, the best candidate was overexpressed in the same strain. All of the 12 genes encoding putative Esterases were expressed. Esterase PF#279 was predicted to be secreted in the medium, PF#774 to be surface exposed, and the 10 remaining putative Esterases to be intracellular. Zymography revealed that Esterase activities in culture supernatant differed from the ones detected in intracellular extracts. PF#279 was identified as the sole Esterase present in culture supernatant. Transformed P. freudenreichii CIRM1 clones overexpressing PF#279 showed 5 to 8 times more lipolytic activity on milk fat than the wild-type strain. Combining in silico, biochemical, and genetic approaches, we showed that PF#279 is the sole secreted Esterase in P. freudenreichii and is active on milk fat. Therefore, it is likely a key component in cheese lipolysis by P. freudenreichii.