• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1223-1229
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• 2009

To construct a new recombinant strain of Bacillus velezensis that has antifungal and insecticidal activity via the expression of the insecticidal Bacillus thuringiensis crystal protein, a B. thuringiensis expression vector (pHT1K-1Ac) was generated that contained the B. thuringiensis cry1Ac gene under the control of its endogenous promoter in a minimal E. coli-B. thuringiensis shuttle vector (pHT1K). This vector was introduced into a B. velezensis isolate that showed high antifungal activities against several plant diseases, including rice blast (Magnaporthe grisea), rice sheath blight (Rhizotonia solani), tomato gray mold (Botrytis cinerea), tomato late blight (Phytophthora infestans), and wheat leaf rust (Puccinia recondita), by electroporation. The recombinant B. velezensis strain was confirmed by PCR using cry1Ac-specific primers. Additionally, the recombinant strain produced a protein approximately 130 kDa in size and parasporal inclusion bodies similar to B. thuringiensis. The in vivo antifungal activity assay demonstrated that the activity of the recombinant B. velezensis strain was maintained at the same level as that of wild-type B. velezensis. Furthermore, it exhibited high insecticidal activity against a lepidopteran pest, Plutella xylostella, although its activity was lower than that of a recombinant B. thuringiensis strain, whereas wild-type B. velezensis strain did not show any insecticidal activity. These results suggest that this recombinant B. velezensis strain can be used to control harmful insect pests and fungal diseases simultaneously in one crop.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.89-93
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• 2004

Expression of a fusion protein between B. thuringiensis crystal protein, Cry1Ac1 and a scorpion insect toxin (AaIT, Androctonus australis Hector insect toxin) in acrystalliferous B. thuringiensis strain (Cry-B strain) was examined. The cry 1Ac1 gene was cloned in B. thuringiensis-E coli shuttle vector, pHT3101, under the control of the native cry 1Ac1 gene promoter (pProAc) and a gene encoding AaIT was inserted in XhoI site in the middle of the cry 1Ac1 gene (pProAc-ScoR). B. thuringiensis Cry-B strain carrying pProAc-ScoR (PyoAc-ScoR/CB) produced an inclusion body of irregular shape and the expressed fusion protein is approximately 65 kDa in size. Sporulated cells and spore-crystal mixtures of ProAc-ScoR/CB had insecticidal activity against Plutella xylostella larvae, showing $LT_50$ of ProAc-ScoR/CB (22.59 hrs) lower than that of ProAc/CB (30.06 hrs) at $1{\times}{10^7} {CEU/cm^2}$. These results suggest that the fusion protein including a B. thuringiensis crystal protein and an AaIT may be functionally expressed in B. thupingiensis. Moreover, we verified the additive toxicity of AaIT, which is a new feasible candidate for insect control.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.289-297
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• 2021

Bacillus velezensis CJ1, showing significant fibrinolytic activity, was isolated from Myeolchi Jeotgal, a popular Korean fermented seafood. When B. velezensis CJ1 was grown on four different culture media, the culture on the Luria-Bertani (LB) broth showed the highest fibrinolytic activity (102.94 mU/μl) at 48 h. LB was also the best medium for growth. SDS-PAGE of culture supernatant showed four major bands, 38, 35, 27, and 22 kDa in size. Fibrin zymography showed four active bands, 50, 47, 40, and 30 kDa in size. A gene homologous to aprE of the Bacillus species was cloned by PCR. DNA sequencing showed that aprECJ1 can encode a protease consisting of 382 amino acids. The translated amino acid sequence of AprECJ1 showed high identity values with those of B. velezensis strains and other Bacillus species. The aprECJ1 gene was introduced into B. subtilis WB600 using an E. coli-Bacillus shuttle vector, pHY300PLK, and overexpressed. A 27 kDa band corresponding to the mature form of AprECJ1 was produced and confirmed by SDS-PAGE and fibrin zymography. B. subtilis WB600 [pHYaprECJ1] showed 1.8-fold higher fibrinolytic activity than B. velezensis CJ1 at 48 h.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.389-398
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• 2009

Development of expression vectors is important for the basic and applied researches on kimchi LAB (lactic acid bacteria). An expression vector, pSJE6c was constructed by inserting P6C promoter sequence from Lactococcus lactis into pSJE, a shuttle vector for E. coli and Leuconostoc species. To test the efficiency of pSJE6c, aga ($\alpha$-galactosidase) and lacZ ($\beta$-galactosidase) genes were expressed in Lactobacillus brevis 2.14. Compared to the pSJE, expression levels of both genes were increased, indicating P6C promoter was better than indigenous promoters. Enzyme activities of L. brevis cells harboring pSJE6caga (pSJE6c with aga) or pSJE6Z (pSJE6c with lacZ) were 1.5-2 fold higher than those with pSJEaga (pSJE with aga) or pSJEZ (pSJE with lacZ). More RNA transcripts were detected in cells harboring pSJE6c based recombinant plasmid. The results indicated that heterologous gene expressions in kimchi LAB could be improved significantly by use of efficient expression vectors.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.300-305
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• 2005

A transcriptionally active fragment $(P_{19})$ isolated by utilizing the promoter-probe shuttle vector pSK1Cat was analyzed. By subcloning analysis, the 180 bp region $(P_{180})$ responsible for the activity was determined. Transcriptional fusion of the C. glutamicum metX gene to $P_{180}\;(P_{180}-metX)$ resulted in a 24-fold increase in MetX activity in a complex medium, while a 13-fold increase was observed with the $P_{tac}$ promoter. Additionally, the expression conferred by $P_{180}$ was not affected by methionine added to the growth medium, suggesting that the $P_{180}$ clone is useful for the deregulated expression of biosynthetic genes in C. glutamicum during amino acid fermentation. Introduction of $P_{180}-metX$ into a lysine-producing C. glutamicum resulted in the production of methionine to 0.8 g/l.

• KSBB Journal
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• v.17 no.2
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• pp.162-168
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• 2002

Human ferritin H- and L-chain genes(hfH and hfL) were cloned into the yeast shuttle vector YEp352 with various promoters, and the vectors constructed were used to transform Saccharomyces cerevisiae 2805. Three different promoters fused to hfH and hfL were used: galactokinase 1 (GAL1) promoter, glyceraldehyde-3-phosphate dehydrogenase(GPD) promoter and alcohol dehydrogenase 1(ADH1 ) promoter. SDS-polyacrylamide gel electrophoresis and Western blotting analyses displayed expression of the introduced hfH and hfL. In the production of both ferritin H and L subunits GAL1 promoter was more effective than GPD promoter or ADH1 promoter. Ferritin H and L subunits produced in S. cerevisiae were spontaneously assembled into its holoproteins as proven on native polyacrylamide gels. Both recombinant H and L-chain ferritins were catalytically active in forming iron core. When the cells were cultured in the medium containing 10 mM ferric citrate, the cell-associated concentration of iron was 174.9 $\mu\textrm{g}$ Per gram(dry cell weight) for the recombinant yeast YG-L and 148.8 $\mu\textrm{g}$ Per gram(dry cell weight) for the recombinant yeast YG-L but was 49.4 $\mu\textrm{g}$ Per gram(dry cell weight) in the wild type, indicating that the iron contents of yeast is improved by heterologous expression of human ferritin H-chain or L-chain genes.

• KSBB Journal
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• v.11 no.3
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• pp.270-275
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• 1996

Heterologous expression of glucose oxidase gene using recombinant yeast has been carried out. Polymerase chain reaction was conducted to obtain the gene encoding glucose oxidase from Aspergillus niger and sequence comparison indicated the cloned 1.9kb DNA fragment appeared to be the glucose oxidise structural gene containing a signal sequence for extracellular location. Transforming shuttle vector was constructed with YEp352 to express the cloned glucose oxidase gene under the control of either GAL1 or GAL10 promoter. Plate assay of recombinant yeasts has shown that GAL1 promoter was more effective in yielding glucose oxidise than GAL10 promoter. Among the five different concentrations of galactose tried, 1% galactose showed the highest induction of glucose oxidase. Cellular localization experiment of recombinant enzyme using spheroplast revealed that most of enzymes (80%) were secreted into culture media in contrast to A. niger. There is no difference in heat-stability of recombinant enzyme up to $50^{\circ}C$ compared to the glucose oxidase from A. niger However, a dramatic reduction of enzyme activity was observed in both enzymes at $60^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.149-152
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• 2006

Leuconostoc mesenteroides SY1, a strain isolated from cabbage Kimchi, was transformed with pCW4, a shuttle vector based on a cryptic plasmid from Lactobacillus paraplantarum C7. $\alpha-Amylase$ gene, amyL, from Bacillus licheniformis was cloned into pCW4, resulting in $pCW4T{\alpha},\;and\;pCW4T{\alpha}$ was introduced into SY1 by electroporation. Transformation efficiency was $10^2cells/{\mu}g$ plasmid DNA. L. mesenteroides cells harboring $pCW4T{\alpha}$ did not show amylase activity, although amyL transcript was synthesized as determined by slot blot experiment. $pCW4T{\alpha}$ was stably maintained in SY1 in the presence of erythromycin (Em, $5\;{\mu}g/ml$) but rapidly lost when Em was omitted. Less than $1\%$ of the cells maintained $pCW4T{\alpha}$ after 5 days at $30^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.2 no.4
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• pp.243-247
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• 1992

The thr operon of Escherichia coli TF427, an $\alpha$-amino-$\beta$-hydroxyvaleric acid (AHV)-resistant threonine overproducer, was cloned in a pBluescriptII $KS^＋$ plasmid by complementation of E. coli mutants. All clones contained a common 8.8 kb HindIII-generated DNA fragment and complemented the thrA, thrB, and thrC mutants by showing that these clones contained the whole thr operon. This thr operon was subcloned in the plasmid vectors pBR322, pUC18, and pECCG117, an E. coli/Corynebacterium glutamicum shuttle vector, to form recombinant plasmids pBTF11, pUTF25 and pGTF18, respectively. The subcloned thr operon was shown to be present in a 6.0 kb insert. A transformant of E. coli TF125 with pBTF11 showed an 8~11 fold higher aspartokinase I activity, and 15~20 fold higher L-threonine production than TF125, an AHV-sensitive methionine auxotroph. Also, it was found that the aspartokinase I activity of E. coli TF125 harboring pBTF11 was not inhibited by threonine and its synthesis was not repressed by threonine plus isoleucine.

• BMB Reports
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• v.34 no.4
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• pp.379-384
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• 2001

The cDNA encoding ribosomal protein was identified from a cDNA library of Schizosaccharomyces pombe. The nucleotide sequence of the 548 by cDNA clone reveals an open reading frame, which encodes a putative protein of 166 amino acids with a molecular mass of 18.3 kDa. The amino acid sequence of the S. pombe L11 protein is highly homologous with those of rat and fruit, while it is clearly less similar to those of prokaryotic counterparts. The 1,044 by upstream sequence, and the region encoding N-terminal 7 amino acids of the genomic DNA were fused into the promoterless $\beta$-galactosidase gene of the shuttle vector YEp357 in order to generate the fusion plasmid pHY L11. Synthesis of $\beta$-galactosidase from the fusion plasmid varied according to the growth curve. It decreased significantly in the growth-arrested yeast cells that were treated with aluminum chloride and mercuric chloride. However, it was enhanced by treatments with cadmium chloride ($2.5\;{\mu}M$), zinc chloride ($2.5\;{\mu}M$), and hydrogen peroxide (0.5 mM). This indicates that the expression of the L,11 gene could be induced by oxidative stress.