• Korean Journal of Microbiology
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• v.29 no.4
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• pp.203-208
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• 1991

The dapA-complementing gene (L-2, 3-dihydrodipicolinate synthetase: DHDP synthetase, dapA) has been cloned by using a cosmid genomic bank of Corynebacterium glutamicum JS231 that is a lysine overproducer, AEC (s-(2-aminoethyl)-L-cysteine) resistant mutant. By enzymatic deletion analysis, the DNA region complementing the escherichia coli dapA host could be confined to 4.5kb SalI-generated DNA fragment. This DNA fragment was inserted into the C. glutamicum/E. coli shuttle vector pECCG117 to construct pDHDP5812. The specific activity of DHDP synthetase detected in C. glutamicum JS231/pDHDP5812 was increased about 10 fold above that of C. glutamicum JS231. The addition of leucine during growth did not repress the expressin of dapA, and the enzyme activity was not inhibited by lysine.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.389-396
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• 1993

An Actinomycetes strain JB isolated from Mt. Hanla had a strong antimicrobial activity against gram positive bacteria and tumor cell growth inhibition. Especially, it couldn't degrade starch and casein as organic compounds. It was resist on lincomycin and rifampicin. The spore mass of strain JB which was arethrospore was white. DAP of the cell wall was L, L-DAP. Antimicrobial material was heat stable, dissolved in ethyl acetate, and not dissolved in butanol. In the pressnce of 0.1% phenol and 4% sodium chloride, strain JB could grow, but it didn't growth at below $10^{\circ}C$. Strain JB didn't use dextran, sodium acetate and sodium citrate as sole carbon source and L-cystein and L-thereonine as nitrogen source. The filtered broth of strain JB had the antimicrobial activity against gram positive bacteria, especially Staphylococcus aureus (ATCC 65389) and the growth inhibition of tumor cell line.

• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.52.1-52.11
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• 2021

Objectives: This study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration. Materials and Methods: Intact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]₂; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05. Results: Ca(OH)₂ and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used. Conclusions: Ca(OH)₂ and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.802-805
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• 2001

The dapD gene of Brevibacterium lactofermentum encoding tetrahydrodipicolinate N-succinyl transferase, one of the enzymes involved in lysine biosynthesis, was cloned by complementation of Escherichia coli dapD mutnat. The recombinant plasmid pLS1 was found to contain a 3.6 kb DNA fragment. Southern hybridization analysis confirmed that the cloned DNA fragment originated from B. lactofermentum. The data of L-lysine production showed that the B. lactofermentum dapD gene was expressed in E. coli.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.19-27
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• 2005

Antioxidative polyethylene films for food packaging were experimentally prepared by fortification of TBHQ(tertiary butylhydroquinone) and dl-a-tocopherol at the weight ratio of 0.05, 0.2 and 0.5%, respectively and laminated with nylon. TBHQ and tocopherol contents in the PE/nylon film were analyzed and the antioxidative effects of film were investigated on the lipid oxidation of semi-dried squid during storage at 5℃ and l5℃. TBHQ contents of TAP 1(TBHQ 0.05%), TAP 2(TBHQ 0.2%) and TAP 3(0.5%) were 38, 146 and 365 mg/100g, respectively. Tocopherol contents of DAP l(tocopherol 0.05%), DAP 2(tocopherol 0.2%) and DAP 3(tocopherol 0.5%) were 33, 139 and 356 mg/l00g, respectively. TBA value and POV during storage of semi-drid squid were affected both by storage temperatures and packaging films. Lipid oxidation during storage was retarded by anti-oxidative films, as TBA value of TAP 3 and DAP 3 revealed about 50% of control after storage at 5℃ for 20 days and similer effects in POV were also observed.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.226-232
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• 2016

Dihydrodipicolinate reductase is an enzyme that converts dihydrodipicolinate to tetrahydrodipicolinate using an NAD(P)H cofactor in L-lysine biosynthesis. To increase the understanding of the molecular mechanisms of lysine biosynthesis, we determined the crystal structure of dihydrodipicolinate reductase from Corynebacterium glutamicum (CgDapB). CgDapB functions as a tetramer, and each protomer is composed of two domains, an Nterminal domain and a C-terminal domain. The N-terminal domain mainly contributes to nucleotide binding, whereas the C-terminal domain is involved in substrate binding. We elucidated the mode of cofactor binding to CgDapB by determining the crystal structure of the enzyme in complex with NADP⁺ and found that CgDapB utilizes both NADH and NADPH as cofactors. Moreover, we determined the substrate binding mode of the enzyme based on the coordination mode of two sulfate ions in our structure. Compared with Mycobacterium tuberculosis DapB in complex with its cofactor and inhibitor, we propose that the domain movement for active site constitution occurs when both cofactor and substrate bind to the enzyme.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.387-392
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• 1998

Brevibacterium lactofermentum, a gram-positive bacteria, has both the diaminopimelate (DAP) pathway and meso-DAP-dehydrogenase (DDH) pathway for L-lysine biosynthesis. To investigate importance of DDH pathway and the related ddh gene in lysine production, we introduced site-specific mutagenesis technique. A 300 bp DNA fragment central to the meso-DAP-dehydrogenase gene (ddh) of B. lactofermentum was used to inactive chromosomal ddh gene via homologous recombination. Southern hybridization analysis confirmed that the chromosomal ddh gene was disrupted by the vector sequence. The B. lactofementum ddh mutant obtained have an inactive DDH pathway. The results reveal that inactivation of the ddh gene in B. lactofermentum leads to dramatic reduction of lysine production as well as decrease of the growth rate, indicating that the DDH pathway is essential for high-level lysine production as well as biosynthesis of meso-DAP.

• Journal of Microbiology and Biotechnology
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• v.19 no.3
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• pp.238-249
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• 2009

The genus Listeria consists of six closely related species and forms three phylogenetic groups: L. monocytogenes-L. innocua, L. ivanovii-L. seeligeri-L. welshimeri, and L. grayi. In this report, we attempted to examine the evolutionary relationship in the L. monocytogenes-L. innocua group by probing the nucleotide sequences of 23S rRNA and 16S rRNA, and the gene clusters lmo0029-lmo0042, ascB-dapE, rplS-infC, and prs-ldh in L. monocytogenes serovars 1/2a, 4a, and 4b, and L. innocua. Additionally, we assessed the status of L. monocytogenes-specific inlA and inlB genes and 10 L. innocua-specific genes in these species/serovars, together with phenotypic characterization by using in vivo and in vitro procedures. The results indicate that L. monocytogenes serovar 4a strains are genetically similar to L. innocua in the lmo0035-lmo0042, ascB-dapE, and rplS-infC regions and also possess L. innocua-specific genes lin0372 and lin1073. Furthermore, both L. monocytogenes serovar 4a and L. innocua exhibit impaired intercellular spread ability and negligible pathogenicity in mouse model. On the other hand, despite resembling L. monocytogenes serovars 1/2a and 4b in having a nearly identical virulence gene cluster, and inlA and inlB genes, these serovar 4a strains differ from serovars 1/2a and 4b by harboring notably altered actA and plcB genes, displaying strong phospholipase activity and subdued in vivo and in vitro virulence. Thus, by possessing many genes common to L. monocytogenes serovars 1/2a and 4b, and sharing many similar gene deletions with L. innocua, L. monocytogenes serovar 4a represents a possible evolutionary intermediate between L. monocytogenes serovars 1/2a and 4b and L. innocua.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.598-602
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• 1994

Light-induced electron transfer reaction within binuclear complex $(NC)_5FeII-L-CoIII(NH_3)_5$ was studied with steady-state photolysis and the rate constants were measured for various bridging lignands. klight and quantum yields for BP, PHEN, DAP having conjugation between metal binding sites were about $3{\times}10^{-2} sec^{-1}$ and 1, and for BPEA having no conjugation were about $2{\times}10^{-4} sec^{-1}$ and 0.03. Light-induced electron transfer reaction within binuclear complex was proved to be the chemical mechanism which had charge transfer excited state MLCT*.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.173-173
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• 2022

In this study, we investigated whether there is another amaranth GBSS isoform in an attempt to characterize the synthesis of amylose in the pericarp. We used I2/KI staining to analyze the temporal and spatial starch accumulation patterns during seed development. The spatiotemporal starch accumulation patterns in developing seeds were observed by staining with I2/KI. Starch granules were observed in the pericarp in the initial developmental stage (3 DAP). A few starch granules were detected in the perisperm in the early-late developmental stage (8 DAP), during which the pericarp starch contents rapidly decreased. Starch granules were distributed throughout the perisperm in the mid-late developmental stage (15 DAP). Similar results were reported for other cereal crops, including barley, rice, and sorghum. Starch granules in the pericarp are synthesized during the early seed developmental stages but are absent in mature seeds. We recently reported that starch deposits in the perisperm of developing amaranth seeds are detectable only after the initial developmental stage. Prior to this stage, the pericarp is the major site of starch deposition. A recent study suggested that GBSSII isoforms are responsible for amylose synthesis in pericarps.