• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.303-309
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• 1990

In order to study the effect of diet supplemented with 0.015% (150ppm) of L-tryptophan on the performance of broiler breeder, the performance of parent stock of 1768 breeder(Hubbard) fed on the diet supplemented with L tryptophan was compared with those of 1105 breeders fed on the basal (control) diet Henday egg and settable egg production, fertility, hatchability and number of quality chicks per settable egg were recorded during 133 days(34－52 week－old) of experimental feeding period. Also during 28 days of after experimental feeding period(53－56 week－old) the henday egg and settable egg production were recorded. The henday egg production of breeder fed L-tryptophan was similar with that fed the control diet during 7 weeks of the peak laying period(34－41 week－old) after beginning of the experimental feeding but which was significantly(P＜0.05) higher during 84 days of the post peak laying period(41－52 week－old) and 28 days of after experimental feeding period(53－56 week－old) than those of control And birds fed the L-tryptophan layed significantly (P＜0.01) higher numbers of the sellable eggs than those fed control diet during the post peak laying and after experimental feeding periods. While the coefficient of variance for the henday egg and settable egg production were shown lower values in birds fed the diet supplemented with L-tryptophan compared with those fed the control diet Also the diet containing L-tryptophan did not affect fertility and hatchability of settable egg though the number of quality chicks per sellable egg was higher significantly(P＜0.05) in birds fed the L-tryptophan than that fed the control diet.

• Journal of Life Science
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• v.9 no.6
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• pp.733-736
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• 1999

The doubly altered mutant tryptophan synthase $\alpha$-subunits, in which Thr 24 was replaced by Ser, Leu or Lys in addition to F139W substitution, were purified. Urea-induced unfolding equilibrium curves of these proteins, monitored by fluorescence intensity of tryptophan, show that the alterations of residue 24 resulted in marked changes in folding properites, suggesting the importance of this residue in folding of this protein.

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.350-355
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• 2008

• Journal of Life Science
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• v.21 no.2
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• pp.316-321
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• 2011

Generation of tryptophan-derived metabolites by indoleamine 2,3-dioxygenase (IDO) is a potent immunoregulatory mechanism in T cell responses. However, the mechanism remains unclear. We showed that 3-hydroxyanthranilic acid (3-HAA), the most potent metabolite, selectively induced apoptosis in activated T cells, but not in resting T cells. This was not associated with cell cycle arrest. We found that TRAIL expression was selectively induced in activated T cells by treatment of 3-HAA. Blockade of the TRAIL: DR4/DR5 pathway significantly inhibited 3-HAA-mediated T cell death. Our data suggest that TRAIL-induced apoptosis is involved in the mechanism of 3-HAA-mediated T cell death.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.450-456
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• 1988

For optimal production of L-tryptophan using a regulatory mutant of Escherichia coli the relationship between product formation and acid production was investigated. Experimental results showed that the production level of L-tryptophan was lowered as the specific acid production rate increased. In order to reduce the amount of acid produced during the fermentation, a controlled fed-batch fermentation was employed. In this fed-batch process, the feed rate of the nutrient feed medium was controlled in relation to the oxygen level in the culture and thus the growth of the cells was regulated in such n way that the oxygen demand of the culture could not exceed the oxygen sup-ply. When E. coli cells were cultivated in a controlled fed-batch mode of tormentor operation, the specific acid production rate was significantly reduced and L-tryptophan production was increased as much as five times that obtained in a conventional fed-batch fermentation.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.186-195
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• 2015

Anthranilate synthase (AS) is a key enzyme in the biosynthesis of tryptophan (Trp), which is the precursor of bioactive metabolites like indole-3-acetic acid and other indole alkaloids. Alpha anthranilate synthase 2 (OsASA2) plays a critical role in the feedback inhibition of tryptophan biosynthesis. In this study, two vectors with single (F124V) and double (S126F/L530D) point mutations of the OsASA2 gene for feedback-insensitive ${\alpha}$ subunit of rice anthranilate synthase were constructed and transformed into wildtype Dongjinbyeo by Agrobacterium-mediated transformation. Transgenic single and double mutant lines were selected as a single copy using TaqMan PCR utilized nos gene probe. To select intergenic lines, the flanking sequence of RB or LB was digested with a BfaI enzyme. Four intergenic lines were selected using a flanking sequence tagged (FST) analysis. Expression in rice (Oryza sativa L.) of the transgenes resulted in the accumulation of tryptophan (Trp), indole-3-acetonitrile (IAN), and indole-3-acetic acid (IAA) in leaves and tryptophan content as a free amino acid in seeds also increased up to 30 times relative to the wildtype. Two homozygous event lines, S-TG1 and D-TG1, were selected for characterization of agronomic traits and metabolite profiling of seeds. Differentially expressed genes (DEGs), related to ion transfer and nutrient supply, were upregulated and DEGs related to co-enzymes that work as functional genes were down regulated. These results suggest that two homozygous event lines may prove effective for the breeding of crops with an increased level of free tryptophan content.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.515-518
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• 2010

D,L-tryptophans were separated by using $Chirobiotic^{(R)}$ T HPLC column. Mobile phases were the mixture of methanol and water(70:30, 80:20, 90:10, v/v). Experimental temperatures were adjusted as 25, 40 and $55^{\circ}C$ in order to compare retention times. Difference in D,L-tryptophan retention times was studied in terms of the interaction between stationary phase and tryptophans. Selectivity, resolution and efficiency of column were utilized to find an optimum separation condition. Retention times were shortened by increasing the amount of methanol in mobile phase and the temperature of column. The best selectivity and resolution was obtained with the temperature($25^{\circ}C$) and the ratio of mobilephase(70/30 v/v%).

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.407-412
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• 1988

In order to increase the tryptophan productivity of E. coli SB1007, a mutant resistant to sulfanilamide was isolated and then a tyrosine auxotroph TY-90 was derived from the sulfanilamide-resistant mutant SA3-39-16. In the test-tube culture a quantitative amount of tryptophan was accumulated in strain TY-90 but in a jar fermentor culture the productivity was lower as compared to the level obtained by the parent strain. From the double auxotrophic mutant SB2756, a revertant resistant to 2, 000$\mu\textrm{g}$/$m\ell$ of $\beta$-thienylalanine, TA 40-10, was selected and then phenylalanine auxotrophs were derived from the revertant strain TA-40-10. One of the phenylalanine auxotrophs, TP-4, accumulated 3.7g/$\ell$ of L-tryptophan after 71-hr cultivation in a jar fermentor experiment.

• Journal of Life Science
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• v.9 no.2
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• pp.146-152
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• 1999

In order to elucidate a role of residue 24 in the folding of tryptophan synthase $\alpha$ subunit, mutant proteins in which Thr 24 was replaced by Met, Ala, Ser, Leu or Lys were overexpressed in E. coli, and the extents of accumulated proteins as soluble or aggregated forms were examined. The mutant proteins with Met or Leu at residue 24 were predominantly accumulated as soluble forms as the native protein. On the other hand, mutant proteins with Ser, Ala or Lys at residue 24 were expressed as aggregated forms as well. This result suggests that residue 24 of tryptophan synthase $\alpha$ subunit may be implicated in the folding of this protein.

• Journal of Life Science
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• v.30 no.10
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• pp.919-929
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• 2020

Aromatic compounds are widely used in the chemical, food, polymer, cosmetic, and pharmaceutical industries and are produced by mainly chemical synthesis using benzene, toluene, and xylene or by plant extraction methods. Due to many rising threats, including the depletion of fossil fuels, global warming, the strengthening of international environmental regulations, and the excessive harvesting of plant resources, the microbial production of aromatic compounds using renewable biomass is regarded as a promising alternative. By integrating metabolic engineering with synthetic and systems biology, artificial biosynthetic pathways have been reconstituted from L-tryptophan biosynthetic pathway in relevant microorganisms, such as Escherichia coli and Corynebacterium glutamicum, enabling the production of a variety of value-added aromatic compounds, such as 5-hydroxytryptophan, serotonin, melatonin, 7-chloro-L-tryptophan, 7-bromo-L-tryptophan, indigo, indirubin, indole-3-acetic acid, violacein, and dexoyviolacein. In this review, we summarize the characteristics, usage, and biosynthetic pathways of these aromatic compounds and highlight the latest metabolic engineering strategies for the microbial production of aromatic compounds and suitable solution strategies to overcome problems in increasing production titers. It is expected that strain development based on systems metabolic engineering and the optimization of media and bioprocesses using renewable biomass will enable the development of commercially viable technologies for the microbial production of many aromatic compounds.