• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.722-725
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• 1999

Filamentation-suppressed recombinant Escherichia coli strain harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes and the E. coli ftsZ gene was constructed and cultivated for the production of poly(3-hydroxybutyrate) [P(3HB)] with high concentration and high content. By the pH-stat fed-batch culture of this recombinant E. coli strain XL1-Blue(pJC5), the final cell concentration and P(3HB) concentration obtained in 44.25h were 172.2g cell dry weight/l and 141.9g P(3HB)/l, respectively, resulting in productivity of 3.21g P(3HB)/l-h. More importantly, the P(3HB) content obtained was 82.4 wt %, which was significantly higher than that obtained with the recombinant E. coli harboring only the PHA biosynthesis genes.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.255-259
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• 1999

A 6.9-kb DNA fragment including the minimal Bacillus pasteurii urease gene cluster was subcloned into a high-copy-number plasmid vector, pUC19, and the recombinant B. pasteurii urease was overexpressed in Escherichia coli. The recombinant urease was purified 25.9-fold by using combinations of anion-exchange and gel-filtration chromatography followed by Mono-Q chromatography on a FPLC. N-terminal peptide sequencing analyses revealed that two distinct smaller peptide bands resolved on a 10-18％ gradient SDS-PAGE corresponded to UreA and UreB peptides, respectively. It was also shown that the ureB gene was translated from a GUG codon and the first methionine residue was post-translationally cleaved off. The native molecular weight of the recombinant urease was 176,000 and 2 nickel atoms were present per catalytic unit. pH stability studies of the purified enzyme showed that the recombinant Bacillus pasteurii urease is stable in alkaline pH range, which is similar to the enzyme of the evolutionarily related bacterium, Sporosarcina ureae.

• Journal of Sericultural and Entomological Science
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• v.38 no.1
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• pp.36-41
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• 1996

Recombinant baculoviruses having expanded host range were selected by coinfection of Autographa california NPV and Bombyx mori NPV into Sf-9 and BmN-4 insect cell lines. In order to determine the polyhedra morhplogy of RecS-A6, one of a recombinant baculovirus, polyhedra of RecS-A6 produced in insect cells were observed by phase contrast microscope and scanning electron microscope. The results revealed that the recombinant baculovirus had a various polyhedra morphology which was different from its parental viruses, suggesting that the various morhpology of recombinant baculovirus with an expanded host range was due to the genetic recombination of viral genome. To analyze the genomic recombinantion of the recombinant baculoviruses, genomic DNAs of two parent viruses and RecS-A6 were digested with restriction endonuclease and subjected to agarose gel electrophoresis. Southern blot analysis revealed that RecS-A6 has two polyhedrin gene of AcNPV and BmNPV in a viral genome. Polyhedral protein of recombinant baculovirus was analysed by SDS-PAGE. The result showed that molecular weight of polyhedral protein of RecS-A6 containing two polyhedrin gene of AcNPV and BmNPV was as the 31 kDa band of AcNPV and 30 kDa band of BmNPV.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.786-796
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• 1999

As an attempt to develop an effective control method against theileriosis, recombinant antigen protein was produced. Thirty-two kDa membrane protein(MP) gene of T sergenti was amplified through RT-PCR from extracted total RNA of T sergenti isolated in Chonbuk, Korea. The amplified 869 bp of Korean T sergenti membrane gene was cloned and the base sequences were analyzed. The amplified gene was cloned into E coli expression vector, pQE32 plasmid vector, and the vector was introduced into E coli strain M15 to produce the recombinant membrane protein. For the induction of T sergenti membrane protein(KTs-MP), the plasmid harboring E coli strain M15 were cultured in the presence of IPTG, and the recombinant protein were purified by $Ni^+$-NTA agarose. Then, to confirm the authenticity of the produced membrane protein, molecular weight of expressed recombinant KTs-MP was analyzed by SDS-PAGE and Western blotting. The molecular weight of expressed recombinant protein was 32 kDa as expected. The recombinant KTs-MP was successfully recognized by anti-His Tag antibody, antisera of T sergenti infected cattle and monoclonal antibody of T sergenti membrane protein. Therefore, we concluded that the authentic 32 kDa membrane protein of T sergenti was produced as immunologically recognizable form.

• The Journal of Korean Society of Virology
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• v.27 no.1
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• pp.29-37
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• 1997

To use recombinant viruses with wider host range as viral insecticides, we investigated the characteristics and pathogenicity of host range expanded recombinant viruses in insect cells. We compared host range expanded recombinant viruses, RecS-B6 and RecB-8, constructed by cotransfection of Autographa californica nuclear polyhedrosis virus (AcNPV) and Bombyx mori NPV (BmNPV), to host range expanded AcNPV, Ac-BH, by substitution of the 0.6 Kb fragment of the BmNPV helicase gene. Restriction endonuclease profiles of RecS-B6 and RecB-8 DNAs were different from those of parent viruses. Nucleotide sequence analysis of the 0.6 Kb region in the putative helicase gene of RecS-B6 and RecB-8 showed that their structures were identical to the counterpart region of BmNPV. Comparison of viral replication of these recombinant viruses in Sf-21 and BmN-4 cells showed that Ac-BH, compared to wild type viruses, replicated well in BmN-4 cells but poorly in Sf-21 cells. In contrast, RecS-B6 and RecB-8 replicated relatively well in both cells compared to parent viruses. These results may imply that random genomic recombinant viruses, RecS-B6 and RecB-8, possess better potential as viral pesticides than helicase-mediated recombinant virus, Ac-BH.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.288-296
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• 1995

To investigate high-level expression of Serratia marcescens metalloprotease (SMP) in Escherichia coli and S. marcescens, we constructed various recombinant plasmids: pSP2, containing SMP gene and lac promoter; pKSP2, containing SMP gene and tac promoter; pTSP2, containing SMP gene, trc99a promoter, and lacI$^{q}$. The recombinant E. coli (pKSP2) strain expressed SMP to a high-level, about 36% of total cellular proteins but accumulated inactive SMP precursors intracellularly, which indicated that E. coli does not have activation and secretion system for SMP. To overproduce active SMP, we transformed S. marcescens with the recombinant plasmids by a modified CaCl$_{2}$ method. The recombinant S. marcescens ATCC27117 (pSP2) containing lac promoter for SMP transcription produced 530 U/ml of active SMP on LB broth, which is about 5.1 times of the SMP yield, 105 U/ml of a control strain, S. marcescens ATCC27117 (pUC19). However, S. marcescens ATCC27117 (pKSP2) containing tac promoter for SMP transcription did not grow healthy and hardly produced SMP. To overcome a harmful effect of the strong tac promoter, we constructed a regulatory plasmid pTSP2 containing a strong trc99a promoter and its repressor gene lacI$^{q}$. When S. marcescens ATCC27117 (pTSP2) was induced with 1.0 mM IPTG after 9 hr cultivation, 2,200 U/ml of SMP was obtained in LB broth, which is about 21 times of that of a control strain.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.182-190
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• 2003

A new phaC gene cluster encoding polyhydroxyalkanoate (PHA) synthase I PHA depolymerase, and PHA synthase II was cloned using the touchdown PCR method, from medium-chain length (mcl-) PHA-producing strain Pseudomonas putida KT2440. The molecular structure of the cloned phaCl gene was analyzed, and the phylogenic relationship was compared with other phaCl genes cloned from Pseudomonas species. The cloned phaCl gene was expressed in a recombinant E. coli to the similar level of PHA synthase in the parent strain P. putida KT2440, but no significant amount of mcl-PHA was accumulated. The isolated phaCl gene was re-introduced into the parent strain P. putida KT2440 to amplify the PHA synthase I activity, and the recombinant P. purida accumulated mcl-PHA more effectively, increasing from 26.6 to $43.5\%$. The monomer compositions of 3-hydroxylalkanoates in mcl-PHA were also modified significantly in the recombinant P. putida enforcing the cloned phaCl gene.

• Reproductive and Developmental Biology
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• v.36 no.3
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• pp.193-198
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• 2012

This study was to examine expression of the recombinant full-length adiponectin (recombinant adiponectin) in insect ovarian cell culture system and to characterize structural properties of the recombinant adiponectin secreted in medium. Gene construct encoding the recombinant adiponectin contained N-terminal collagen-like domain (110 Amino Acids, AAs), C-terminal globular domain (137 AAs) and C-terminal peptides for detection with V5 antibody (26 AAs included adaptor peptide) and purification using the 6xHis tag (6 AAs). The approximate molecular weight of the product (monomer) was 35 kDa. Molecular mass species of the expressed recombinant adiponectin were monomer (~35 kDa), dimer (~70 kDa), trimer (~105 kDa) and hexamer (~210 kDa). The major secreted species were the LMW forms, such as monomer, dimer, and trimer. There was MMW of hexamer as minor form. HMW multimers (~300 kDa) were shown as a tracer or not detected on the SDS-PAGE in several experiments (data not shown). The multimer forms in this study were not compatible to those in animal or human serum and adipose tissue by other researcher's study in which the major multimer forms were HMW. By protein denaturing experiments with reducing reagent (${\beta}$-MeOH), anionic detergent (SDS) and heat ($95^{\circ}C$) on the SDS-PAGE, not all adiponectin multimers seemed to have disulfide bond linked structure to form multimers. The recombinant adiponectin which expressed in insect ovarian cell culture system seemed to have the limitation as full physiological regulator for the application to animal and human study.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.386-392
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• 2015

A novel recombinant bacmid, bEasyBm, that enables the easy and fast generation of pure recombinant baculovirus without any purification step was constructed. In bEasyBm, attR recombination sites were introduced to facilitate the generation of a recombinant viral genome by in vitro transposition. Moreover, the extracellular RNase gene from Bacillus amyloliquefaciens, barnase, was expressed under the control of the Cotesia plutellae bracovirus early promoter to negatively select against the nonrecombinant background. The bEasyBm bacmid could only replicate in host insect cells when the barnase gene was replaced with the gene of interest by in vitro transposition. When bEasyBm was transposed with pDualBac-EGFP, the resulting recombinant virus, EasyBm-EGFP, showed high levels of EGFP expression efficiency compared with that of non-purified recombinant virus BmGOZA-EGFP, which was constructed using the bBmGOZA system. In addition, nonrecombinant backgrounds were not detected in unpurified EasyBm-EGFP stocks. Based on these results, a high-throughput system for the generation of multiple recombinant viruses at a time was established.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1685-1689
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• 2014

Baeyer-Villiger (BV) oxidation of cyclohexanone to ${\varepsilon}$-caprolactone in a microbial system expressing cyclohexanone monooxygenase (CHMO) can be influenced by not only the efficient regeneration of NADPH but also a sufficient supply of oxygen. In this study, the bacterial hemoglobin gene from Vitreoscilla stercoraria (vhb) was introduced into the recombinant Escherichia coli expressing CHMO to investigate the effects of an oxygen-carrying protein on microbial BV oxidation of cyclohexanone. Coexpression of Vhb allowed the recombinant E. coli strain to produce a maximum ${\varepsilon}$-caprolactone concentration of 15.7 g/l in a fed-batch BV oxidation of cyclohexanone, which corresponded to a 43% improvement compared with the control strain expressing CHMO only under the same conditions.