• 농업과학연구
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• 제44권1호
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• pp.30-39
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• 2017

This study was performed to produce succinic acid from biomass by developing mutants of Cellulomonas flavigena in which the succinate dehydrogenase gene (sdh) is deleted. For development of succinate producing mutants, the upstream and downstream regions of sdh gene from C. flavigena and antibiotic resistance gene (neo, bla) were inserted into pKC1139, and the recombinant plasmids were transformed into Escherichia coli ET12567/pUZ8002 which is a donor strain for conjugation. C. flavigena was conjugated with the transformed E. coli ET12567/pUZ8002 to induce the deletion of sdh in chromosome of this bacteria by double-crossover recombination. Two mutants (C. flavigena H-1 and H-2), in which sdh gene was deleted in the chromosome, were constructed and confirmed by PCR. To estimate the production of succinic acid by the two mutants when the culture broth was fermented with biomass such as CMC, xylan, locust gum, and rapeseed straw; the culture broth was analyzed by HPLC analysis. The succinic acid in the culture broth was not detected as a fermentation products of all biomass. One of the reasons for this may be the conversion of succinic acid to fumaric acid by sdh genes (Cfla_1014 - Cfla_1017 or Cfla_1916 - Cfla_1918) which remained in the chromosomal DNA of C. flavigena H-1 and H-2. The other reason could be the conversion of succinyl-CoA to other metabolites by enzymes related to the bypass pathway of TCA cycle.

• BMB Reports
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• 제46권7호
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• pp.358-363
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• 2013

In this paper, we firstly reported a C-type lectin cDNA clone of 1029 bps from the larvae of A. Pernyi (Ap-CTL) using PCR and RACE techniques. The full-length cDNA contains an open reading frame encoding 308 amino acid residues which has two different carbohydrate-recognition domains (CRDs) arranged in tandem. To investigate the biological activities in the innate immunity, recombinant Ap-CTL was expressed in E. coli with a 6-histidine at the amino-terminus (Ap-rCTL). Besides acted as a broad-spectrum recognition protein binding to a wide range of PAMPs and microorganisms, Ap-rCTL also had the ability to recognize and trigger the agglutination of bacteria and fungi. In the proPO activation assay, Ap-rCTL specifically restored the PO activity of hemolymph blocked by anti-Ap-rCTL antibody in the presence of different PAMPs or microorganisms. In summary, Ap-rCTL plays an important role in insect innate immunity as an pattern recognition protein.

• International Journal of Industrial Entomology and Biomaterials
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• 제23권2호
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• pp.231-238
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• 2011

Attacin is an insect antibacterial protein that plays an important role in immune response to injury and infection. In this report, we have isolated and characterized of cDNA encoding for the attacin from the immunized larvae of swallowtail butterfly, $Papilio$ $xuthus$. A full length cDNA of $P.$ $xuthus$ attacin was obtained by employing annealing control primer (ACP)-based differential display PCR and 5' RACE. The complete $P.$ $xuthus$ attacin cDNA was comprised of 949 bp encoding a 250 amino acid precursor. It contains a putative 18 amino acid signal peptide sequence, a 42 amino acid propeptide sequence, and a 190 amino acid mature protein with a theoretical molecular mass of 19904.01 and a pI of 9.13. The putative mature protein of $P.$ $xuthus$ attacin showed 48-52% and 24-30% identity in amino acid sequences with that of lepidopteran and dipteran insects, respectively. Semiquantitive RT-PCR results revealed that the transcript of $P.$ $xuthus$ attacin gene was up-regulated at significant levels after injection with bacterial lipopolysaccharide (LPS). We sub-cloned cDNA fragment encoding mature $P.$ $xuthus$ attacin into the expression vector, highly expressed in $E.$ $coli$ BL21 cells, and its antibacterial activity was analyzed. Recombinant $P.$ $xuthus$ attacin evidenced considerably antibacterial activity against Gram-negative bacteria, $E.$ $coli$ ML 35 and $Klebsiella$ $pneumonia$.

• 한방안이비인후피부과학회지
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• 제11권1호
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• pp.1-22
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• 1998

During the last few years, nitric oxide(NO) as a potent macrophage-derived effector molecule against a variety of bacteria, parasites, and tumors has received increasing attention. More recent studies suggest that NO also has antiviral effects in both murine and human cells. The objective of the current study was to determine the effect of Yongdamsagantang(YST) on the production of NO. Stimulation of mouse peritoneal macrophages with YST after the treatment of recombinant $interferon-{\gammer}(rlFN-{\gammer})$ resulted in the increased NO synthesis. YST had no effect on NO synthesis by itself. When YST was used in combination with $rIFN-{\gammer}$, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. The optimal effect of YST on NO synthesis was shown 6 hour after treatment with $rIFN-{\gammer}$. This increase in NO synthesis was reflected as increased amount of inducible NO synthase(iNOS) protein. NO production was inhibited by $N^G-monomethyl-L-arginine$. The increased production of NO from $rIFN-{\gammer}$ plus YST-stimulated cells was decreased by the treatment with staurosporin. In addition, synergy between $rIFN-{\gammer}$ and YST was mainly dependent on YST-induced tumor necrosis $factor-{\alpha}(TNF-{\alpha})$ secretion. These results suggest that the capacity of YST to increase NO production from $rIFN-{\alpha}-primed$ mouse peritoneal macrophages is the result of YST-induced $TNF-{\alpha}$ secretion.

• Journal of Microbiology
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• 제40권2호
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• pp.156-160
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• 2002

The whole gal/lae operon genes of Lactococcus lactis ssp. lactis 7962 were reported as follows: galA-galM-galK-galT-lacA -lacZ-galE. The galK gene encoding a galactokinase involved in one of the Leloir pathways for galactose metabolism was found to be 1,197 bp in length and encodes a protein of 43,822 Da calculated molecular mass. The deduced amino acid sequence showed over 50% homology with GaIK proteins from several other lactic acid bacteria. The galK gene was expressed in E. coli and the product was identified as a 43 kDa protein which corresponds to the estimated size from the DNA sequence. The galactokinase activity of recombinant 5. coli was about 8 times greater against that of the host strain and more than 3 times higher than the induced L. lactis 7962.

• 생명과학회지
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• 제16권1호
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• pp.44-48
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• 2006

L-alanine의 산업적 생산을 위한 신규의 L-aspartate $\beta-carboxylase$ 유전자를 Enterococcus faecalis에서 검색하고 이를 대장균에 형질전환시켰다. E. faecalis 유래의 ADC유전자 는 1611 bp의 염기서열로 구성되어 있으며 형질전환된 대장균에서 59 KDa의 효소를 생산하며 L-aspartate $\beta-carboxylase$의 촉매활성을 나타내는 것을 확인하였다. 본 연구결과로 기능은 모르고 유전체 서열만 아는 균체에서 신규 효소를 개발하는 방법을 확립하였으며 저가의 aspartate를 이용한 고부가가치 L-alanine을 생산할 수 있는 신규효소를 개발할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.822-829
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• 2007

A gene coding for phosphoketolase, a key enzyme of carbohydrate catabolism in heterofermentative lactic acid bacteria(LAB), was cloned from a Lactobacillus paraplantarum C7 and expressed in Escherichia coli. The gene is 2,502 bp long and codes for a 788-amino-acids polypeptide with a molecular mass of 88.7 kDa. A Shine-Dalgarno sequence(aaggag) and an inverted-repeat terminator sequence are located upstream and downstream of the phosphoketolase gene, respectively. The gene exhibits an identity of >52% with phosphoketolases of other LAB. The phosphoketolase of Lb. paraplantarum C7(LBPK) contains several highly conserved phosphoketolase signature regions and typical thiamine pyrophosphate(TPP) binding sites, as reported for other TPP-dependent enzymes. The phosphoketolase gene was fused to a glutathione S-transferase(GST::LBPK) gene for purification. The GST::LBPK fusion protein was detected in the soluble fraction of a recombinant Escherichia coli BL21. The GST::LBPK fusion protein was purified with a yield of 4.32mg/400ml by GSTrap HP affinity column chromatography and analyzed by N-terminal sequencing. LBPK was obtained by factor Xa treatment of fusion protein and the final yield was 3.78mg/400ml. LBPK was examined for its N-terminal sequence and phosphoketolase activity. The $K_M\;and\;V_{max}$ values for fructose-6-phosphate were $5.08{\pm}0.057mM(mean{\pm}SD)$ and $499.21{\pm}4.33{\mu}mol/min/mg$, respectively, and the optimum temperature and pH for the production of acetyl phosphate were $45^{\circ}C$ and 7.0, respectively.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1714-1723
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• 2012

${\beta}$-Glucosidase is necessary for the bioconversion of glycosidic phytochemicals in food. Two Bifidobacterium strains (Bifidobacterium animalis subsp. lactis SH5 and B. animalis subsp. lactis RD68) with relatively high ${\beta}$-glucosidase activities were selected among 46 lactic acid bacteria. A ${\beta}$-glucosidase gene (bbg572) from B. lactis was shotgun cloned, fully sequenced, and analyzed for its transcription start site, structural gene, and deduced transcriptional terminator. The structural gene of bbg572 was 1,383 bp. Based on amino sequence similarities, bbg572 was assigned to family 1 of the glycosyl hydrolases. To overexpress bbg572 in Bifidobacterium, several bifidobacteria expression vectors were constructed by combining several promoters and a terminator sequence from different bifidobacteria. The maximum activity of recombinant Bbg572 was achieved when it was expressed under its own promoter and terminator. Its enzyme activity increased 31-fold compared with those of its parental strains. The optimal pH for Bbg572 was pH 6.0. Bbg572 was stable at $37-40^{\circ}C$. It hydrolyzed isoflavones, quercetins, and disaccharides with various ${\beta}$-glucoside linkages. Bbg572 also converted the ginsenosides Rb1 and Rb2. These results suggest that this new ${\beta}$-glucosidase-positive Bifidobacterium transformant can be utilized for the production of specific aglycone products.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1221-1226
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• 2008

The soft rot bacterium Pectobacterium wasabiae is an economically important pathogen of many crops. A new phytase gene, appA, was cloned from P. wasabiae by degenerate PCR and TAIL-PCR. The open reading frame of appA consisted of 1,302 bp encoding 433 amino acid residues, including 27 residues of a putative signal peptide. The mature protein had a molecular mass of 45 kDa and a theoretical pI of 5.5. The amino acid sequence contained the conserved active site residues RHGXRXP and HDTN of typical histidine acid phosphatases, and showed the highest identity of 48.5% to PhyM from Pseudomonas syringae. The gene fragment encoding the mature phytase was expressed in Escherichia coli BL21 (DE3), and the purified recombinant phytase had a specific activity of 1,072$\pm$47 U/mg for phytate substrate. The optimum pH and temperature for the purified phytase were pH 5.0 and 50$^{\circ}C$, respectively. The $K_m$ value was 0.17 mM, with a $V_{max}$ of 1,714 $\mu$mol/min/mg. This is the first report of the identification and isolation of phytase from Pectobacterium.

• Journal of Microbiology and Biotechnology
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• 제31권3호
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• pp.483-491
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• 2021

Two putative genes, lip29 and est29, encoding lipolytic enzymes from the thermophilic bacterium Geobacillus thermocatenulatus KCTC 3921 were cloned and overexpressed in Escherichia coli. The recombinant Lip29 and Est29 were purified 67.3-fold to homogeneity with specific activity of 2.27 U/mg and recovery of 5.8% and 14.4-fold with specific activity of 0.92 U/mg and recovery of 1.3%, respectively. The molecular mass of each purified enzyme was estimated to be 29 kDa by SDS-PAGE. The alignment analysis of amino acid sequences revealed that both enzymes belonged to GDSL lipase/esterase family including conserved blocks with SGNH catalytic residues which was mainly identified in plants before. While Est29 showed high specificity toward short-chain fatty acids (C4-C8), Lip29 showed strong lipolytic activity to long-chain fatty acids (C12-C16). The optimal activity of Lip29 toward p-nitrophenyl palmitate as a substrate was observed at 50℃ and pH 9.5, respectively, and its activity was maintained more than 24 h at optimal temperatures, indicating that Lip29 was thermostable. Lip29 exhibited high tolerance against detergents and metal ions. The homology modeling and substrate docking revealed that the long-chain substrates showed the greatest binding affinity toward enzyme. Based on the biochemical and insilico analyses, we present for the first time a GDSL-type lipase in the thermophilic bacteria group.