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Dayananda Siddavattam - One of the best experts on this subject based on the ideXlab platform.
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Organophosphate hydrolase is a lipoprotein and interacts with pi specific transport system to facilitate growth of brevundimonas diminuta using op insecticide as source of phosphate
2016Co-Authors: Sunil Parthasarathy, Hari Parapatla, Aparna Nandavaram, Tracy Palmer, Dayananda SiddavattamAbstract:Organophosphate hydrolase (OPH), encoded by the Organophosphate degradation (opd) island, hydrolyzes the triester bond found in a variety of Organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane of Brevundimonas diminuta in a pre-folded conformation by the twin arginine transport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the pre-OPH in the cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of the ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pi generated from Organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consistent with this model, opd null mutants of B. diminuta failed to grow using the Organophosphate insecticide methyl parathion as sole source of phosphate.
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Organophosphate Hydrolase Is a Lipoprotein and Interacts with Pi-specific Transport System to Facilitate Growth of Brevundimonas diminuta Using OP Insecticide as Source of Phosphate.
2016Co-Authors: Sunil Parthasarathy, Hari Parapatla, Aparna Nandavaram, Tracy Palmer, Dayananda SiddavattamAbstract:Abstract Organophosphate hydrolase (OPH), encoded by the Organophosphate degradation (opd) island, hydrolyses the triester bond found in a variety of Organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane of Brevundimonas diminuta in a pre-folded conformation by the Twin Arginine Transport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the preOPH in cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pi generated from Organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consisent with this model, opd null mutants of B. diminuta failed to grow using the Organophosphate insecticide methyl parathion as sole source of phosphate.
Frank M Raushel - One of the best experts on this subject based on the ideXlab platform.
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molecular engineering of Organophosphate hydrolysis activity from a weak promiscuous lactonase template
2013Co-Authors: Monika M Meier, Chitra Rajendran, Christoph Malisi, Nicholas G Fox, Sandra Schlee, David P Barondeau, Birte Hocker, Reinhard Sterner, Frank M RaushelAbstract:Rapid evolution of enzymes provides unique molecular insights into the remarkable adaptability of proteins and helps to elucidate the relationship between amino acid sequence, structure, and function. We interrogated the evolution of the phosphotriesterase from Pseudomonas diminuta (PdPTE), which hydrolyzes synthetic Organophosphates with remarkable catalytic efficiency. PTE is thought to be an evolutionarily “young” enzyme, and it has been postulated that it has evolved from members of the phosphotriesterase-like lactonase (PLL) family that show promiscuous Organophosphate-degrading activity. Starting from a weakly promiscuous PLL scaffold (Dr0930 from Deinococcus radiodurans), we designed an extremely efficient Organophosphate hydrolase (OPH) with broad substrate specificity using rational and random mutagenesis in combination with in vitro activity screening. The OPH activity for seven Organophosphate substrates was simultaneously enhanced by up to 5 orders of magnitude, achieving absolute values of ca...
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Molecular Engineering of Organophosphate Hydrolysis Activity from a Weak Promiscuous Lactonase Template
2013Co-Authors: Monika M Meier, Chitra Rajendran, Christoph Malisi, Nicholas G Fox, Sandra Schlee, David P Barondeau, Reinhard Sterner, Birte Höcker, Frank M RaushelAbstract:Rapid evolution of enzymes provides unique molecular insights into the remarkable adaptability of proteins and helps to elucidate the relationship between amino acid sequence, structure, and function. We interrogated the evolution of the phosphotriesterase from Pseudomonas diminuta (PdPTE), which hydrolyzes synthetic Organophosphates with remarkable catalytic efficiency. PTE is thought to be an evolutionarily “young” enzyme, and it has been postulated that it has evolved from members of the phosphotriesterase-like lactonase (PLL) family that show promiscuous Organophosphate-degrading activity. Starting from a weakly promiscuous PLL scaffold (Dr0930 from Deinococcus radiodurans), we designed an extremely efficient Organophosphate hydrolase (OPH) with broad substrate specificity using rational and random mutagenesis in combination with in vitro activity screening. The OPH activity for seven Organophosphate substrates was simultaneously enhanced by up to 5 orders of magnitude, achieving absolute values of catalytic efficiencies up to 106 M–1 s–1. Structural and computational analyses identified the molecular basis for the enhanced OPH activity of the engineered PLL variants and demonstrated that OPH catalysis in PdPTE and the engineered PLL differ significantly in the mode of substrate binding
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detoxification of Organophosphate nerve agents by bacterial phosphotriesterase
2005Co-Authors: Eman Ghanem, Frank M RaushelAbstract:Organophosphates have been widely used as insecticides and chemical warfare agents. The health risks associated with these agents have necessitated the need for better detoxification and bioremediation tools. Bacterial enzymes capable of hydrolyzing the lethal Organophosphate nerve agents are of special interest. Phosphotriesterase (PTE) isolated from the soil bacteria Pseudomonas diminuta displays a significant rate enhancement and substrate promiscuity for the hydrolysis of Organophosphate triesters. Directed evolution and rational redesign of the active site of PTE have led to the identification of new variants with enhanced catalytic efficiency and stereoselectivity toward the hydrolysis of Organophosphate neurotoxins. PTE has been utilized to protect against Organophosphate poisoning in vivo. Biotechnological applications of PTE for detection and decontamination of insecticides and chemical warfare agents are developing into useful tools. In this review, the catalytic properties and potential applications of this remarkable enzyme are discussed.
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phosphotriesterase a promising candidate for use in detoxification of Organophosphates
1994Co-Authors: Kai Tuovinen, Eila Kalistekorhonen, Frank M Raushel, Osmo HänninenAbstract:Abstract Phosphotriesterase—A Promising Candidate for Use in Detoxification of Organophosphates. Tuovinen, K., Kalistekorhonen, E., Raushel, F. M., and Hanninen, O. (1994). Fundam. Appl Toxicol 23, 578-584. The effect of phosphotriesterase (PTE) on cholinesterase (ChE) activities was studied with exposures to different Organophosphates in mice. Paraoxon (PO) (1.0 mg/kg, ip) almost totally inhibited serum ChE activity. This activity, however, recovered to the normal level within 24 hr. The PTE pretreatment (16.8 U/animal, 2.5 μg/10 g body wt, iv 10 min before the Organophosphate) accelerated this reactivation. The same phenomenon was also seen in vitro. In vitro with human serum, there was only minimal reactivation of the inhibited ChE. PTE, however, reactivated it significantly. The PTE-pretreated mice (168 U/animal, 30 μg/10 g body wt, iv) tolerated even 50 mg/kg of PO without showing any remarkable signs of intoxication, In PTE-untreated animals, however, PO doses as low as 1.0 and 1.5 mg/kg caused severe signs of poisoning. PTE (16.8 U/animal, 4 μg/10 g body wt, iv) reduced the inhibition of brain and serum ChE activities after PO and diisopropyl fluorophosphate exposure. In sarin and soman intoxications. PTE decreased only slightly the inhibition of ChE activities. The results indicate that PTE pretreatment given iv prevents the inhibition of ChE activities after certain Organophosphates and it also hastens the recovery of activities after PO poisoning.
Sunil Parthasarathy - One of the best experts on this subject based on the ideXlab platform.
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Organophosphate hydrolase is a lipoprotein and interacts with pi specific transport system to facilitate growth of brevundimonas diminuta using op insecticide as source of phosphate
2016Co-Authors: Sunil Parthasarathy, Hari Parapatla, Aparna Nandavaram, Tracy Palmer, Dayananda SiddavattamAbstract:Organophosphate hydrolase (OPH), encoded by the Organophosphate degradation (opd) island, hydrolyzes the triester bond found in a variety of Organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane of Brevundimonas diminuta in a pre-folded conformation by the twin arginine transport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the pre-OPH in the cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of the ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pi generated from Organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consistent with this model, opd null mutants of B. diminuta failed to grow using the Organophosphate insecticide methyl parathion as sole source of phosphate.
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Organophosphate Hydrolase Is a Lipoprotein and Interacts with Pi-specific Transport System to Facilitate Growth of Brevundimonas diminuta Using OP Insecticide as Source of Phosphate.
2016Co-Authors: Sunil Parthasarathy, Hari Parapatla, Aparna Nandavaram, Tracy Palmer, Dayananda SiddavattamAbstract:Abstract Organophosphate hydrolase (OPH), encoded by the Organophosphate degradation (opd) island, hydrolyses the triester bond found in a variety of Organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane of Brevundimonas diminuta in a pre-folded conformation by the Twin Arginine Transport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the preOPH in cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pi generated from Organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consisent with this model, opd null mutants of B. diminuta failed to grow using the Organophosphate insecticide methyl parathion as sole source of phosphate.
Aaron J Gassmann - One of the best experts on this subject based on the ideXlab platform.
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evaluation of pyrethroids and Organophosphates in insecticide mixtures for management of western corn rootworm larvae
2020Co-Authors: Coy R St Clair, Edmund J Norris, Kenneth E Masloski, Joel R Coats, Aaron J GassmannAbstract:Background The western corn rootworm is an economically important pest of corn. Management tactics include pyrethroid and Organophosphate insecticides, which may be applied as a mixture to protect corn roots. The goal of our study was to characterize the effects of pyrethroids and Organophosphates alone and in combination on larval corn rootworm mortality and injury to corn roots. We evaluated two insecticide combinations: tebupirimphos with β-cyfluthrin and chlorethoxyfos with bifenthrin. Using a soil-based, laboratory bioassay, we exposed larvae to five concentrations of the pyrethroid alone, the Organophosphate alone, the combined formulation, and a water control. We calculated LC50 values and co-toxicity factors to determine synergism or antagonism between Organophosphates and pyrethroids. We also measured adult emergence and root injury in a field experiment that tested tebupirimphos alone, β-cyfluthrin alone, the combined formulation, and an untreated control. Results Bioassay results indicated antagonism between the pyrethroid and Organophosphate at most concentrations for both insecticide combinations. In the field experiment, tebupirimphos alone or in combination with β-cyfluthrin significantly reduced adult emergence and root injury compared to the untreated controls, but β-cyfluthrin alone did not differ from the untreated control for either metric. Conclusions These results suggest that, at the concentrations tested, the pyrethroid component of pyrethroid-Organophosphate mixtures may not contribute to a reduction of rootworm emergence or root injury. While these pyrethroids may confer a management benefit for other pests, such as seedcorn maggot, the concentrations of pyrethroids present in current formulations of these mixtures are likely too low for effective rootworm management. © 2020 Society of Chemical Industry.
Ali H Sayyed - One of the best experts on this subject based on the ideXlab platform.
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evidence for resistance to pyrethroids and Organophosphates in plutella xylostella lepidoptera plutellidae from pakistan
2007Co-Authors: A Khaliq, M N R Attique, Ali H SayyedAbstract:The susceptibility of representative pyrethroid (cypermethrin, deltamethrin, lambdacyhalothrin, bifenthrin), Organophosphate (chlorpyriphos, triazophos, profenophos) and new chemistry insecticides (spinosad, indoxacarb and emamectin) was investigated for 18 field populations of Plutella xylostella (Linnaeus) from three different zones in Pakistan. The LC 50 (mg ml _1 ; 48 h) values of pyrethroids for various populations ranged from 0.19-1.88 for cypermethrin, 0.31-2.64 for deltamethrin, 0.08-1.16 for lambdacyhalothrin and 0.07-0.88 for bifenthrin. The LC 50 (mg ml _1 ; 48 h) of Organophosphates ranged from 0.52-5.67 for chlorpyriphos, 0.37-4.14 for triazophos and 0.03-2.65 for profenophos. The most probable reason for low toxicity of Organophosphates and pyrethroids is the evolution of multiple resistance mechanisms; however, further studies are required to establish these mechanisms. When these same products were tested against a susceptible laboratory population (Lab-Pak), the new chemistry compounds were significantly more toxic than pyrethroids and Organophosphates. The results are discussed in relation to integrated pest management and insecticide resistance management strategies for P. xylostella.
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stability of field selected resistance to insecticides in plutella xylostella lep plutellidae from pakistan
2005Co-Authors: Ali H Sayyed, M N R Attique, A KhaliqAbstract:: To investigate fluctuation in susceptibility to insecticides, natural populations of Plutella xylostella were collected from the same field in the region of Multan, Pakistan, in late summer, mid-winter and early spring. After bulking up for a generation in the laboratory, the populations were examined against pyrethroids and Organophosphates as well as newer insecticides (spinosad, indoxacarb and emamectin). Each population showed a broad range of variation in susceptibility to all chemicals. Comparison between populations collected in different times of years in 2003 and 2004 showed variation in susceptibility to Organophosphates and pyrethroids. In winter, susceptibility to Organophosphates increased, whereas it decreased in relation to pyrethroids. However, susceptibility to the newer insecticides was unchanged within the season. The results suggest that the fluctuation observed in susceptibility could be either associated with fitness costs of Organophosphate and pyrethroids or cessation of insecticides. These results might have important implications in resistance management. We propose a strategy for application of insecticides in relation to P. xylostella management in Pakistan.
