The Experts below are selected from a list of 27549 Experts worldwide ranked by ideXlab platform
Arjen M Dondorp - One of the best experts on this subject based on the ideXlab platform.
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Artemisinin resistant plasmodium falciparum malaria
Microbiology spectrum, 2016Co-Authors: Rick M Fairhurst, Arjen M DondorpAbstract:For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to Artemisinins, the world’s most potent antimalarial drugs. In areas where Artemisinin resistance is prevalent, Artemisinin combination therapies (ACTs)—the first-line treatments for malaria—are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in vitro, genomics, and transcriptomics studies in SEA have defined in vivo and in vitro phenotypes of Artemisinin resistance, identified its causal genetic determinant, explored its molecular mechanism, and assessed its clinical impact. Specifically, these studies have established that Artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early-ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite’s K13 gene, is associated with an upregulated “unfolded protein response” pathway that may antagonize the pro-oxidant activity of Artemisinins, and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent, test whether new combinations of currently available drugs cure ACT failures, and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of Artemisinin and partner drug resistance from SEA to sub-Saharan Africa, where the world’s malaria transmission, morbidity, and mortality rates are highest.
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the threat of Artemisinin resistant malaria
The New England Journal of Medicine, 2011Co-Authors: Arjen M Dondorp, Rick M Fairhurst, Laurence Slutsker, John R Macarthur, G Joel M D Breman, Philippe J Guerin, Thomas E Wellems, Pascal Ringwald, Robert D Newman, Christopher V PloweAbstract:Since the 1970s, when Chinese researchers demonstrated the Artemisinins' antimalarial potency, Artemisinin-based combination therapy has become key to malaria control. But reduced susceptibility of Plasmodium falciparum to Artemisinin is now being seen in some places.
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exploring the contribution of candidate genes to Artemisinin resistance in plasmodium falciparum
Antimicrobial Agents and Chemotherapy, 2010Co-Authors: Mallika Imwong, Arjen M Dondorp, Poravuth Yi, Francois Nosten, Mathirut Mungthin, Sarun Hanchana, Aung Phae Phyo, Khin Maung LwinAbstract:The reduced in vivo sensitivity of Plasmodium falciparum has recently been confirmed in western Cambodia. Identifying molecular markers for Artemisinin resistance is essential for monitoring the spread of the resistant phenotype and identifying the mechanisms of resistance. Four candidate genes, including the P. falciparum mdr1 (pfmdr1) gene, the P. falciparum ATPase6 (pfATPase6) gene, the 6-kb mitochondrial genome, and ubp-1, encoding a deubiquitinating enzyme, of Artemisinin-resistant P. falciparum strains from western Cambodia were examined and compared to those of sensitive strains from northwestern Thailand, where the Artemisinins are still very effective. The Artemisinin-resistant phenotype did not correlate with pfmdr1 amplification or mutations (full-length sequencing), mutations in pfATPase6 (full-length sequencing) or the 6-kb mitochondrial genome (full-length sequencing), or ubp-1 mutations at positions 739 and 770. The P. falciparum CRT K76T mutation was present in all isolates from both study sites. The pfmdr1 copy numbers in western Cambodia were significantly lower in parasite samples obtained in 2007 than in those obtained in 2005, coinciding with a local change in drug policy replacing artesunate-mefloquine with dihydroArtemisinin-piperaquine. Artemisinin resistance in western Cambodia is not linked to candidate genes, as was suggested by earlier studies.
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Artemisinin resistance current status and scenarios for containment
Nature Reviews Microbiology, 2010Co-Authors: Chea Nguon, Arjen M Dondorp, Duong Socheat, Shunmay Yeung, Lisa J White, Lorenz Von SeidleinAbstract:Artemisinin combination therapies are the first-line treatments for uncomplicated Plasmodium falciparum malaria in most malaria-endemic countries. Recently, partial Artemisinin-resistant P. falciparum malaria has emerged on the Cambodia-Thailand border. Exposure of the parasite population to Artemisinin monotherapies in subtherapeutic doses for over 30 years, and the availability of substandard Artemisinins, have probably been the main driving force in the selection of the resistant phenotype in the region. A multifaceted containment programme has recently been launched, including early diagnosis and appropriate treatment, decreasing drug pressure, optimising vector control, targeting the mobile population, strengthening management and surveillance systems, and operational research. Mathematical modelling can be a useful tool to evaluate possible strategies for containment.
Patrick J Westfall - One of the best experts on this subject based on the ideXlab platform.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Devin R Polichuk, Keat Thomas H TeohAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed. Artemisinin-based combination therapies are the treatment of choice for uncomplicated Plasmodium falciparum malaria, but the supply of plant-derived Artemisinin can sometimes be unreliable, causing shortages and high prices. This manuscript describes a viable industrial process for the production of semisynthetic Artemisinin, with the potential to help stabilize Artemisinin supply. The process uses Saccharomyces cerevisiae yeast engineered to produce high yields of artemisinic acid, a precursor of Artemisinin. The authors have also developed an efficient and scalable chemical process to convert artemisinic acid to Artemisinin. In 2010 there were more than 200 million cases of malaria, and at least 655,000 deaths1. The World Health Organization has recommended Artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum. Artemisinin is a sesquiterpene endoperoxide with potent antimalarial properties, produced by the plant Artemisia annua. However, the supply of plant-derived Artemisinin is unstable, resulting in shortages and price fluctuations, complicating production planning by ACT manufacturers2. A stable source of affordable Artemisinin is required. Here we use synthetic biology to develop strains of Saccharomyces cerevisiae (baker’s yeast) for high-yielding biological production of artemisinic acid, a precursor of Artemisinin. Previous attempts to produce commercially relevant concentrations of artemisinic acid were unsuccessful, allowing production of only 1.6 grams per litre of artemisinic acid3. Here we demonstrate the complete biosynthetic pathway, including the discovery of a plant dehydrogenase and a second cytochrome that provide an efficient biosynthetic route to artemisinic acid, with fermentation titres of 25 grams per litre of artemisinic acid. Furthermore, we have developed a practical, efficient and scalable chemical process for the conversion of artemisinic acid to Artemisinin using a chemical source of singlet oxygen, thus avoiding the need for specialized photochemical equipment. The strains and processes described here form the basis of a viable industrial process for the production of semi-synthetic Artemisinin to stabilize the supply of Artemisinin for derivatization into active pharmaceutical ingredients (for example, artesunate) for incorporation into ACTs. Because all intellectual property rights have been provided free of charge, this technology has the potential to increase provision of first-line antimalarial treatments to the developing world at a reduced average annual price.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Anna Tai, Diana EngAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed.
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Microbially derived semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms: New Concepts and Experimental Approaches, 2013Co-Authors: Christopher J. Paddon, Derek Mcphee, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Jack D NewmanAbstract:© Springer Science+Business Media New York 2013.Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
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Microbially Derived Semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms, 2012Co-Authors: Christopher J. Paddon, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, Jack D NewmanAbstract:Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
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production of amorphadiene in yeast and its conversion to dihydroartemisinic acid precursor to the antimalarial agent Artemisinin
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Patrick J Westfall, Douglas J. Pitera, Rika Regentin, Jacob R Lenihan, Hiroko Tsuruta, Frank X Woolard, Tizita Horning, David J Melis, Andrew Owens, Scott FickesAbstract:Malaria, caused by Plasmodium sp, results in almost one million deaths and over 200 million new infections annually. The World Health Organization has recommended that Artemisinin-based combination therapies be used for treatment of malaria. Artemisinin is a sesquiterpene lactone isolated from the plant Artemisia annua. However, the supply and price of Artemisinin fluctuate greatly, and an alternative production method would be valuable to increase availability. We describe progress toward the goal of developing a supply of semisynthetic Artemisinin based on production of the Artemisinin precursor amorpha-4,11-diene by fermentation from engineered Saccharomyces cerevisiae, and its chemical conversion to dihydroartemisinic acid, which can be subsequently converted to Artemisinin. Previous efforts to produce Artemisinin precursors used S. cerevisiae S288C overexpressing selected genes of the mevalonate pathway [Ro et al. (2006) Nature 440:940–943]. We have now overexpressed every enzyme of the mevalonate pathway to ERG20 in S. cerevisiae CEN.PK2, and compared production to CEN.PK2 engineered identically to the previously engineered S288C strain. Overexpressing every enzyme of the mevalonate pathway doubled artemisinic acid production, however, amorpha-4,11-diene production was 10-fold higher than artemisinic acid. We therefore focused on amorpha-4,11-diene production. Development of fermentation processes for the reengineered CEN.PK2 amorpha-4,11-diene strain led to production of > 40 g/L product. A chemical process was developed to convert amorpha-4,11-diene to dihydroartemisinic acid, which could subsequently be converted to Artemisinin. The strains and procedures described represent a complete process for production of semisynthetic Artemisinin.
Christopher J. Paddon - One of the best experts on this subject based on the ideXlab platform.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Devin R Polichuk, Keat Thomas H TeohAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed. Artemisinin-based combination therapies are the treatment of choice for uncomplicated Plasmodium falciparum malaria, but the supply of plant-derived Artemisinin can sometimes be unreliable, causing shortages and high prices. This manuscript describes a viable industrial process for the production of semisynthetic Artemisinin, with the potential to help stabilize Artemisinin supply. The process uses Saccharomyces cerevisiae yeast engineered to produce high yields of artemisinic acid, a precursor of Artemisinin. The authors have also developed an efficient and scalable chemical process to convert artemisinic acid to Artemisinin. In 2010 there were more than 200 million cases of malaria, and at least 655,000 deaths1. The World Health Organization has recommended Artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum. Artemisinin is a sesquiterpene endoperoxide with potent antimalarial properties, produced by the plant Artemisia annua. However, the supply of plant-derived Artemisinin is unstable, resulting in shortages and price fluctuations, complicating production planning by ACT manufacturers2. A stable source of affordable Artemisinin is required. Here we use synthetic biology to develop strains of Saccharomyces cerevisiae (baker’s yeast) for high-yielding biological production of artemisinic acid, a precursor of Artemisinin. Previous attempts to produce commercially relevant concentrations of artemisinic acid were unsuccessful, allowing production of only 1.6 grams per litre of artemisinic acid3. Here we demonstrate the complete biosynthetic pathway, including the discovery of a plant dehydrogenase and a second cytochrome that provide an efficient biosynthetic route to artemisinic acid, with fermentation titres of 25 grams per litre of artemisinic acid. Furthermore, we have developed a practical, efficient and scalable chemical process for the conversion of artemisinic acid to Artemisinin using a chemical source of singlet oxygen, thus avoiding the need for specialized photochemical equipment. The strains and processes described here form the basis of a viable industrial process for the production of semi-synthetic Artemisinin to stabilize the supply of Artemisinin for derivatization into active pharmaceutical ingredients (for example, artesunate) for incorporation into ACTs. Because all intellectual property rights have been provided free of charge, this technology has the potential to increase provision of first-line antimalarial treatments to the developing world at a reduced average annual price.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Anna Tai, Diana EngAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed.
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Microbially derived semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms: New Concepts and Experimental Approaches, 2013Co-Authors: Christopher J. Paddon, Derek Mcphee, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Jack D NewmanAbstract:© Springer Science+Business Media New York 2013.Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
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Microbially Derived Semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms, 2012Co-Authors: Christopher J. Paddon, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, Jack D NewmanAbstract:Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
Douglas J. Pitera - One of the best experts on this subject based on the ideXlab platform.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Devin R Polichuk, Keat Thomas H TeohAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed. Artemisinin-based combination therapies are the treatment of choice for uncomplicated Plasmodium falciparum malaria, but the supply of plant-derived Artemisinin can sometimes be unreliable, causing shortages and high prices. This manuscript describes a viable industrial process for the production of semisynthetic Artemisinin, with the potential to help stabilize Artemisinin supply. The process uses Saccharomyces cerevisiae yeast engineered to produce high yields of artemisinic acid, a precursor of Artemisinin. The authors have also developed an efficient and scalable chemical process to convert artemisinic acid to Artemisinin. In 2010 there were more than 200 million cases of malaria, and at least 655,000 deaths1. The World Health Organization has recommended Artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum. Artemisinin is a sesquiterpene endoperoxide with potent antimalarial properties, produced by the plant Artemisia annua. However, the supply of plant-derived Artemisinin is unstable, resulting in shortages and price fluctuations, complicating production planning by ACT manufacturers2. A stable source of affordable Artemisinin is required. Here we use synthetic biology to develop strains of Saccharomyces cerevisiae (baker’s yeast) for high-yielding biological production of artemisinic acid, a precursor of Artemisinin. Previous attempts to produce commercially relevant concentrations of artemisinic acid were unsuccessful, allowing production of only 1.6 grams per litre of artemisinic acid3. Here we demonstrate the complete biosynthetic pathway, including the discovery of a plant dehydrogenase and a second cytochrome that provide an efficient biosynthetic route to artemisinic acid, with fermentation titres of 25 grams per litre of artemisinic acid. Furthermore, we have developed a practical, efficient and scalable chemical process for the conversion of artemisinic acid to Artemisinin using a chemical source of singlet oxygen, thus avoiding the need for specialized photochemical equipment. The strains and processes described here form the basis of a viable industrial process for the production of semi-synthetic Artemisinin to stabilize the supply of Artemisinin for derivatization into active pharmaceutical ingredients (for example, artesunate) for incorporation into ACTs. Because all intellectual property rights have been provided free of charge, this technology has the potential to increase provision of first-line antimalarial treatments to the developing world at a reduced average annual price.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Anna Tai, Diana EngAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed.
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Microbially derived semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms: New Concepts and Experimental Approaches, 2013Co-Authors: Christopher J. Paddon, Derek Mcphee, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Jack D NewmanAbstract:© Springer Science+Business Media New York 2013.Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
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Microbially Derived Semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms, 2012Co-Authors: Christopher J. Paddon, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, Jack D NewmanAbstract:Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
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production of amorphadiene in yeast and its conversion to dihydroartemisinic acid precursor to the antimalarial agent Artemisinin
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Patrick J Westfall, Douglas J. Pitera, Rika Regentin, Jacob R Lenihan, Hiroko Tsuruta, Frank X Woolard, Tizita Horning, David J Melis, Andrew Owens, Scott FickesAbstract:Malaria, caused by Plasmodium sp, results in almost one million deaths and over 200 million new infections annually. The World Health Organization has recommended that Artemisinin-based combination therapies be used for treatment of malaria. Artemisinin is a sesquiterpene lactone isolated from the plant Artemisia annua. However, the supply and price of Artemisinin fluctuate greatly, and an alternative production method would be valuable to increase availability. We describe progress toward the goal of developing a supply of semisynthetic Artemisinin based on production of the Artemisinin precursor amorpha-4,11-diene by fermentation from engineered Saccharomyces cerevisiae, and its chemical conversion to dihydroartemisinic acid, which can be subsequently converted to Artemisinin. Previous efforts to produce Artemisinin precursors used S. cerevisiae S288C overexpressing selected genes of the mevalonate pathway [Ro et al. (2006) Nature 440:940–943]. We have now overexpressed every enzyme of the mevalonate pathway to ERG20 in S. cerevisiae CEN.PK2, and compared production to CEN.PK2 engineered identically to the previously engineered S288C strain. Overexpressing every enzyme of the mevalonate pathway doubled artemisinic acid production, however, amorpha-4,11-diene production was 10-fold higher than artemisinic acid. We therefore focused on amorpha-4,11-diene production. Development of fermentation processes for the reengineered CEN.PK2 amorpha-4,11-diene strain led to production of > 40 g/L product. A chemical process was developed to convert amorpha-4,11-diene to dihydroartemisinic acid, which could subsequently be converted to Artemisinin. The strains and procedures described represent a complete process for production of semisynthetic Artemisinin.
Derek James Mcphee - One of the best experts on this subject based on the ideXlab platform.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Devin R Polichuk, Keat Thomas H TeohAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed. Artemisinin-based combination therapies are the treatment of choice for uncomplicated Plasmodium falciparum malaria, but the supply of plant-derived Artemisinin can sometimes be unreliable, causing shortages and high prices. This manuscript describes a viable industrial process for the production of semisynthetic Artemisinin, with the potential to help stabilize Artemisinin supply. The process uses Saccharomyces cerevisiae yeast engineered to produce high yields of artemisinic acid, a precursor of Artemisinin. The authors have also developed an efficient and scalable chemical process to convert artemisinic acid to Artemisinin. In 2010 there were more than 200 million cases of malaria, and at least 655,000 deaths1. The World Health Organization has recommended Artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum. Artemisinin is a sesquiterpene endoperoxide with potent antimalarial properties, produced by the plant Artemisia annua. However, the supply of plant-derived Artemisinin is unstable, resulting in shortages and price fluctuations, complicating production planning by ACT manufacturers2. A stable source of affordable Artemisinin is required. Here we use synthetic biology to develop strains of Saccharomyces cerevisiae (baker’s yeast) for high-yielding biological production of artemisinic acid, a precursor of Artemisinin. Previous attempts to produce commercially relevant concentrations of artemisinic acid were unsuccessful, allowing production of only 1.6 grams per litre of artemisinic acid3. Here we demonstrate the complete biosynthetic pathway, including the discovery of a plant dehydrogenase and a second cytochrome that provide an efficient biosynthetic route to artemisinic acid, with fermentation titres of 25 grams per litre of artemisinic acid. Furthermore, we have developed a practical, efficient and scalable chemical process for the conversion of artemisinic acid to Artemisinin using a chemical source of singlet oxygen, thus avoiding the need for specialized photochemical equipment. The strains and processes described here form the basis of a viable industrial process for the production of semi-synthetic Artemisinin to stabilize the supply of Artemisinin for derivatization into active pharmaceutical ingredients (for example, artesunate) for incorporation into ACTs. Because all intellectual property rights have been provided free of charge, this technology has the potential to increase provision of first-line antimalarial treatments to the developing world at a reduced average annual price.
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high level semi synthetic production of the potent antimalarial Artemisinin
Nature, 2013Co-Authors: Christopher J. Paddon, Douglas J. Pitera, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, A Main, Anna Tai, Diana EngAbstract:Saccharomyces cerevisiae is engineered to produce high concentrations of artemisinic acid, a precursor of the Artemisinin used in combination therapies for malaria treatment; an efficient and practical chemical process to convert artemisinic acid to Artemisinin is also developed.
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Microbially Derived Semisynthetic Artemisinin
Isoprenoid Synthesis in Plants and Microorganisms, 2012Co-Authors: Christopher J. Paddon, Scott Fickes, Douglas J. Pitera, Rika Regentin, Kirsten R Benjamin, Karl Fisher, Patrick J Westfall, Michael D. Leavell, Derek James Mcphee, Jack D NewmanAbstract:Artemisinin is a sesquiterpene lactone endoperoxide with potent antimalarial properties, recommended by the World Health Organization for the treatment of malaria in Artemisinin combination therapies (ACTs). It is extracted from the plant Artemisia annua, but its supplies are limited and its price is volatile. In order to increase supply and stabilize the price of Artemisinin, a semisynthesis has been developed, whereby an Artemisinin precursor (amorpha-4,11-diene) is produced in microbes and the isolated precursor converted chemically to Artemisinin. Escherichia coli has been engineered to produce amorpha-4,11-diene by the expression of a heterologous mevalonate pathway along with amorpha-4,11-diene synthase (ADS) from A. annua. Development of the E. coli platform to increase production of amorpha-4,11-diene from 24 mg/L to >25 g/L is described. ADS has also been expressed in the yeast model system Saccharomyces cerevisiae which, following manipulation of the mevalonate pathway, produced 150 mg/L of amorpha-4,11-diene. The cDNAs encoding the cytochrome P450 that oxidizes amorpha-4,11-diene to artemisinic acid, CYP71AV1, and its cognate reductase were isolated from A. annua and expressed in amorpha-4,11-diene-producing E. coli and yeast, leading to the production of >1 g/L artemisinic acid from both organisms. A route for the chemical conversion of artemisinic acid to Artemisinin is described. Production of semisynthetic Artemisinin may lead to the development of a second source of the drug for incorporation into ACTs.
