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Bang-ce Ye - One of the best experts on this subject based on the ideXlab platform.
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Improvement of L-Ornithine production by attenuation of argF in engineered Corynebacterium glutamicum S9114.
AMB Express, 2018Co-Authors: Bin Zhang, Ying Zhou, Miao Yu, Bang-ce YeAbstract:l-Ornithine, a non-essential amino acid, has enormous industrial applications in food, pharmaceutical, and chemical industries. Currently, l-Ornithine production is focused on microorganism fermentation using Escherichia coli or Corynebacterium glutamicum. In C. glutamicum, development of high l-Ornithine producing C. glutamicum was achieved by deletion of argF, but was accompanied by growth deficiency and arginine auxotrophy. l-Arginine has been routinely added to solve this problem; however, this increases production cost and causes feedback inhibition of N-acetyl-l-glutamate kinase activity. To avoid the drawbacks of growth disturbance due to disruption of ArgF, strategies were adopted to attenuate its expression. Firstly, ribosome binding site substitution and start codon replacement were introduced to construct recombinant C. glutamiucm strains, which resulted in an undesirable l-Ornithine production titer. Then, we inserted a terminator (rrnB) between argD and argF, which significantly improved l-Ornithine production and relieved growth disturbance. Transcription analysis confirmed that a terminator can be used to downregulate expression of argF and simultaneously improve the transcriptional level of genes in front of argF. Using disparate terminators to attenuate expression of argF, an optimal strain (CO-9) with a T4 terminator produced 6.1 g/L of l-Ornithine, which is 42.8% higher than that produced by strain CO-1, and is 11.2-fold higher than that of the parent CO strain. Insertion of terminators with gradient termination intensity can be a stable and powerful method to exert precise control of the expression level of argF in the development of l-Ornithine producing strains, with potential applications in metabolic engineering and synthetic biology.
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Systematic pathway engineering of Corynebacterium glutamicum S9114 for L-Ornithine production.
Microbial Cell Factories, 2017Co-Authors: Bin Zhang, Miao Yu, Yixue Li, Ying Zhou, Bang-ce YeAbstract:l-Ornithine is a non-protein amino acid with extensive applications in medicine and the food industry. Currently, l-Ornithine production is based on microbial fermentation, and few microbes are used for producing l-Ornithine owing to unsatisfactory production titer. In this study, Corynebacterium glutamicum S9114, a high glutamate-producing strain, was developed for l-Ornithine production by pathway engineering. First, argF was deleted to block l-Ornithine to citrulline conversion. To improve l-Ornithine production, ncgl1221 encoding glutamate transporter, argR encoding arginine repressor, and putP encoding proline transporter were disrupted. This base strain was further engineered by attenuating oxoglutarate dehydrogenase to increase l-Ornithine production. Plasmid-based overexpression of argCJBD operon and lysine/arginine transport protein LysE was tested to strengthen l-Ornithine synthesis and transportation. This resulted in efficient l-Ornithine production at a titer of 18.4 g/L. These results demonstrate the potential of Corynebacterium glutamicum S9114 for efficient l-Ornithine production and provide new targets for strain development.
Bin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Improvement of L-Ornithine production by attenuation of argF in engineered Corynebacterium glutamicum S9114.
AMB Express, 2018Co-Authors: Bin Zhang, Ying Zhou, Miao Yu, Bang-ce YeAbstract:l-Ornithine, a non-essential amino acid, has enormous industrial applications in food, pharmaceutical, and chemical industries. Currently, l-Ornithine production is focused on microorganism fermentation using Escherichia coli or Corynebacterium glutamicum. In C. glutamicum, development of high l-Ornithine producing C. glutamicum was achieved by deletion of argF, but was accompanied by growth deficiency and arginine auxotrophy. l-Arginine has been routinely added to solve this problem; however, this increases production cost and causes feedback inhibition of N-acetyl-l-glutamate kinase activity. To avoid the drawbacks of growth disturbance due to disruption of ArgF, strategies were adopted to attenuate its expression. Firstly, ribosome binding site substitution and start codon replacement were introduced to construct recombinant C. glutamiucm strains, which resulted in an undesirable l-Ornithine production titer. Then, we inserted a terminator (rrnB) between argD and argF, which significantly improved l-Ornithine production and relieved growth disturbance. Transcription analysis confirmed that a terminator can be used to downregulate expression of argF and simultaneously improve the transcriptional level of genes in front of argF. Using disparate terminators to attenuate expression of argF, an optimal strain (CO-9) with a T4 terminator produced 6.1 g/L of l-Ornithine, which is 42.8% higher than that produced by strain CO-1, and is 11.2-fold higher than that of the parent CO strain. Insertion of terminators with gradient termination intensity can be a stable and powerful method to exert precise control of the expression level of argF in the development of l-Ornithine producing strains, with potential applications in metabolic engineering and synthetic biology.
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Systematic pathway engineering of Corynebacterium glutamicum S9114 for L-Ornithine production.
Microbial Cell Factories, 2017Co-Authors: Bin Zhang, Miao Yu, Yixue Li, Ying Zhou, Bang-ce YeAbstract:l-Ornithine is a non-protein amino acid with extensive applications in medicine and the food industry. Currently, l-Ornithine production is based on microbial fermentation, and few microbes are used for producing l-Ornithine owing to unsatisfactory production titer. In this study, Corynebacterium glutamicum S9114, a high glutamate-producing strain, was developed for l-Ornithine production by pathway engineering. First, argF was deleted to block l-Ornithine to citrulline conversion. To improve l-Ornithine production, ncgl1221 encoding glutamate transporter, argR encoding arginine repressor, and putP encoding proline transporter were disrupted. This base strain was further engineered by attenuating oxoglutarate dehydrogenase to increase l-Ornithine production. Plasmid-based overexpression of argCJBD operon and lysine/arginine transport protein LysE was tested to strengthen l-Ornithine synthesis and transportation. This resulted in efficient l-Ornithine production at a titer of 18.4 g/L. These results demonstrate the potential of Corynebacterium glutamicum S9114 for efficient l-Ornithine production and provide new targets for strain development.
Susan Spear Bassett - One of the best experts on this subject based on the ideXlab platform.
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Long-term treatment of girls with Ornithine transcarbamylase deficiency.
The New England Journal of Medicine, 1996Co-Authors: Nancy E. Maestri, Saul W Brusilow, David B. Clissold, Susan Spear BassettAbstract:Background Ornithine transcarbamylase is an X-linked mitochondrial enzyme that catalyzes the synthesis of citrulline from carbamoyl phosphate and Ornithine. A deficiency of this enzyme leads to hyperammonemia and hyperglutaminemia. In boys the disease is often fatal when its onset occurs during the neonatal period, but it is milder when onset occurs later in childhood. Heterozygous girls may be normal or may have episodes of hyperammonemic encephalopathy and decline in cognitive function. We report here on the long-term outcome in girls with Ornithine transcarbamylase deficiency enrolled in studies of treatments designed to activate new pathways of waste-nitrogen excretion. Methods We studied 32 girls (age, 1 to 17 years) with Ornithine transcarbamylase deficiency who had had at least one episode of encephalopathy. The patients were assigned to treatment that consisted of sodium benzoate, alone or in combination with sodium phenylacetate or sodium phenylbutyrate, or sodium phenylbutyrate alone. Collaborat...
Laxa Miriam - One of the best experts on this subject based on the ideXlab platform.
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Low CO2 induces urea cycle intermediate accumulation in Arabidopsis thaliana
San Francisco CA : Public Library of Science (PLoS), 2019Co-Authors: Blume Christian, Ost Julia, Mühlenbruch Marco, Peterhänsel Christoph, Laxa MiriamAbstract:The non-proteinogenic amino acid Ornithine links several stress response pathways. From a previous study we know that Ornithine accumulates in response to low CO2. To investigate Ornithine accumulation in plants, we shifted plants to either low CO2 or low light. Both conditions increased carbon limitation, but only low CO2 also increased the rate of photorespiration. Changes in metabolite profiles of light- and CO2-limited plants were quite similar. Several amino acids that are known markers of senescence accumulated strongly under both conditions. However, urea cycle intermediates respond differently between the two treatments. While the levels of both Ornithine and citrulline were much higher in plants shifted to 100 ppm CO2 compared to those kept in 400 ppm CO2, their metabolite abundance did not significantly change in response to a light limitation. Furthermore, both Ornithine and citrulline accumulation is independent from sugar starvation. Exogenous supplied sugar did not significantly change the accumulation of the two metabolites in low CO2-stressed plants, while the accumulation of other amino acids was reduced by about 50%. Gene expression measurements showed a reduction of the entire arginine biosynthetic pathway in response to low CO2. Genes in both proline biosynthesis and degradation were induced. Hence, proline did not accumulate in response to low CO2 like observed for many other stresses. We propose that excess of nitrogen re-fixed during photorespiration can be alternatively stored in Ornithine and citrulline under low CO2 conditions. Furthermore, Ornithine is converted to pyrroline-5-carboxylate by the action of δOAT
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Low CO2 induces urea cycle intermediate accumulation in Arabidopsis thaliana
'Public Library of Science (PLoS)', 2019Co-Authors: Blume Christian, Ost Julia, Muehlenbruch Marco, Peterhaensel Christoph, Laxa MiriamAbstract:Blume C, Ost J, Muehlenbruch M, Peterhaensel C, Laxa M. Low CO2 induces urea cycle intermediate accumulation in Arabidopsis thaliana. PLOS ONE. 2019;14(1): e0210342.The non-proteinogenic amino acid Ornithine links several stress response pathways. From a previous study we know that Ornithine accumulates in response to low CO2. To investigate Ornithine accumulation in plants, we shifted plants to either low CO2 or low light. Both conditions increased carbon limitation, but only low CO2 also increased the rate of photorespiration. Changes in metabolite profiles of light- and CO2-limited plants were quite similar. Several amino acids that are known markers of senescence accumulated strongly under both conditions. However, urea cycle intermediates respond differently between the two treatments. While the levels of both Ornithine and citrulline were much higher in plants shifted to 100 ppm CO2 compared to those kept in 400 ppm CO2, their metabolite abundance did not significantly change in response to a light limitation. Furthermore, both Ornithine and citrulline accumulation is independent from sugar starvation. Exogenous supplied sugar did not significantly change the accumulation of the two metabolites in low CO2-stressed plants, while the accumulation of other amino acids was reduced by about 50%. Gene expression measurements showed a reduction of the entire arginine biosynthetic pathway in response to low CO2. Genes in both proline biosynthesis and degradation were induced. Hence, proline did not accumulate in response to low CO2 like observed for many other stresses. We propose that excess of nitrogen re-fixed during photorespiration can be alternatively stored in Ornithine and citrulline under low CO2 conditions. Furthermore, Ornithine is converted to pyrroline-5-carboxylate by the action of delta OAT
Miao Yu - One of the best experts on this subject based on the ideXlab platform.
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Improvement of L-Ornithine production by attenuation of argF in engineered Corynebacterium glutamicum S9114.
AMB Express, 2018Co-Authors: Bin Zhang, Ying Zhou, Miao Yu, Bang-ce YeAbstract:l-Ornithine, a non-essential amino acid, has enormous industrial applications in food, pharmaceutical, and chemical industries. Currently, l-Ornithine production is focused on microorganism fermentation using Escherichia coli or Corynebacterium glutamicum. In C. glutamicum, development of high l-Ornithine producing C. glutamicum was achieved by deletion of argF, but was accompanied by growth deficiency and arginine auxotrophy. l-Arginine has been routinely added to solve this problem; however, this increases production cost and causes feedback inhibition of N-acetyl-l-glutamate kinase activity. To avoid the drawbacks of growth disturbance due to disruption of ArgF, strategies were adopted to attenuate its expression. Firstly, ribosome binding site substitution and start codon replacement were introduced to construct recombinant C. glutamiucm strains, which resulted in an undesirable l-Ornithine production titer. Then, we inserted a terminator (rrnB) between argD and argF, which significantly improved l-Ornithine production and relieved growth disturbance. Transcription analysis confirmed that a terminator can be used to downregulate expression of argF and simultaneously improve the transcriptional level of genes in front of argF. Using disparate terminators to attenuate expression of argF, an optimal strain (CO-9) with a T4 terminator produced 6.1 g/L of l-Ornithine, which is 42.8% higher than that produced by strain CO-1, and is 11.2-fold higher than that of the parent CO strain. Insertion of terminators with gradient termination intensity can be a stable and powerful method to exert precise control of the expression level of argF in the development of l-Ornithine producing strains, with potential applications in metabolic engineering and synthetic biology.
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Systematic pathway engineering of Corynebacterium glutamicum S9114 for L-Ornithine production.
Microbial Cell Factories, 2017Co-Authors: Bin Zhang, Miao Yu, Yixue Li, Ying Zhou, Bang-ce YeAbstract:l-Ornithine is a non-protein amino acid with extensive applications in medicine and the food industry. Currently, l-Ornithine production is based on microbial fermentation, and few microbes are used for producing l-Ornithine owing to unsatisfactory production titer. In this study, Corynebacterium glutamicum S9114, a high glutamate-producing strain, was developed for l-Ornithine production by pathway engineering. First, argF was deleted to block l-Ornithine to citrulline conversion. To improve l-Ornithine production, ncgl1221 encoding glutamate transporter, argR encoding arginine repressor, and putP encoding proline transporter were disrupted. This base strain was further engineered by attenuating oxoglutarate dehydrogenase to increase l-Ornithine production. Plasmid-based overexpression of argCJBD operon and lysine/arginine transport protein LysE was tested to strengthen l-Ornithine synthesis and transportation. This resulted in efficient l-Ornithine production at a titer of 18.4 g/L. These results demonstrate the potential of Corynebacterium glutamicum S9114 for efficient l-Ornithine production and provide new targets for strain development.
