• Food Science and Biotechnology
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• v.16 no.5
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• pp.778-782
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• 2007

This study assessed the effects of the antimicrobial substances sulforaphane, grapefruit seed extracts (GSE), and reuterin on the expression of Salmonella HilA and InvF virulence gene using a LacZY assay (${\beta}$-galactosidase assay) with hilA:lacZY and invF:lacZY fusion strains of Salmonella typhimurium SL1344. Salmonella was grown for 8 hr at $37^{\circ}C$ in the presence of diluted antimicrobial substances ($2\;{\mu}g/mL$ sulforaphane, $20\{\mu}g/mL$ GSE, and 0.26 mM reuterin) at concentrations that did not inhibit the cellular growth of Salmonella. Sulforaphane inhibited the expression of HilA and InvF by 50-90 and 20-80%, respectively. GSE also inhibited the expression of both genes, but to a lesser degree. Among the 3 antimicrobial substances, reuterin showed the least inhibition, which was abolished after 3-4 hr. None of the antimicrobial substances inhibited the ${\beta}$-galactosidase enzyme activity of S. typhimurium. The assay used in this study represents a very sensitive method for screening bioactive substances that inhibit the expression of virulence genes in Salmonella.

• Journal of Environmental Science International
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• v.3 no.2
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• pp.157-164
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• 1994

Various antimicrobial agents are widely used for the purpose of antimicrobial process. We investigated antimicrobial activity and reduction efficiency of mal-ordour by the diphenyl ether compound (2,4,4'- trichloro -2'- hydroxy diphenyl ether) against Sraphylocom aureus(S.aureus and Proton vulgaris(p.vulgaris causing the mal-ordour, Especially, the diphenyl ether compound is not restricted to the regulation of water-contamination. In this research, we found that the optimum concentration of diphenyl ether compound was 1.5w% for both strains and antimicrobial expressions were c0.38t= 2.56 for S.aureus, c0.38t=2.67 for P.vulgaris. We found also that -OH group played the role of antimicrobial functional group. Lastly, reduction effect of mal-ordour was more than 90% for both strain at the optimum conditions. Key Words : antimicrobial agents, antimicrobial activity, reduction effect of mal-ordour, antimicrobial expression, antimicrobial functional group.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.34-41
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• 1998

A method was developed for the controlled expression of an antimicrobial peptide magainin in Escherichia coli. A series of concatemeric magainin genes was constructed with a gene amplification vector, and fused to the 3'end of malE gene encoding the affinity ligand, E. coli maltose-binding protein (MBP). The construct directed the synthesis of the fusion protein with the magainin polypeptide fused to the C-terminus of MBP. The fusion protein was expressed in a tightly regulatable expression system which was under the control of an invertible promoter. The MBP-fused magainin monomer was expressed efficiently. However, the expression level of the MBP-fused magainin in E. coli decreased with the increasing size of multimers possibly because of the transcription and translation inhibition by the multimeric peptides. After purification using an amylose affinity column, the fusion protein was digested by factor Xa at a specific cleavage site between the monomers. The recombinant magainin had an antimicrobial activity identical to that of synthetic magainin. This experiment shows that a biologically active, antimicrobial peptide magainin can be produced by fusing to MBP, along with a promoter inversion vector system.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.49-54
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• 2018

To artificially enhance antimicrobial peptide expression in Bombyx mori, we constructed genetically engineered silkworms overexpressing Rel family transcription factor. The truncated BmRelish1 (BmRelish1t) gene contained a Rel homolog domain (RHD), nuclear localization signal (NLS), acidic and hydrophobic amino acid (AHAA)-rich region, and death domain (DD), but no ankyrin-repeat (ANK) domain. The BmRelish1t gene was controlled by B. mori cytoplasmic actin 3 promoter in the PiggyBac transposon vector. Chromosome analysis of G1 generations of a transgenic silkworm with EGFP expression confirmed stable insertion of BmRelish1t. BmRelish1t gene overexpression in transgenic silkworms resulted in higher mRNA expression levels of B. mori antimicrobial peptides such as lebocin(~20.5-fold), moricin(~8.7-fold), and nuecin(~17.4-fold) than those in normal silkworms.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.669-671
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• 2000

Antimicrobial cationic peptides have attracted increasing research and clinical interest as a natural antibiotics due to their broad spectrum of antimicrobial activites and the rapid development of multidrug-resistant pathogenic microorganisms. In this study, first, we synthesized artificial fusion partner and cationic peptide genes (lactoferricin, magainin, protegrin-1, and indolicidin). Second, we constructed recombinant expression vectors and then transformed Pichia pastoris. Finally, expressed cationic peptides were purified and tested for their antimicrobial activites. Antimicrobial activity has been tested upon the appearance of clearing zone on the plate with the lawn of gram negative E.coli XL- I blue and garm positive Staphylococcus aureus. Protegrin-1 and Indolicidin have apparant activity of cationic peotides. This fusion technique may lead to a general and suitable tool for production of pure antimicrobial cationic peptides in Pichia pastoris.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.303-310
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• 1999

A cost-effective mass production method for a strong antimicrobial peptide, buforin II, which was isolated from the stomach of Bufo bufo gargarizans, has been developed. This method is based on the neutralization of the positive charge of buforin II by fusion with a cysteine-rich acidic peptide (CAP) to avoid any lethal effect on the host. The neutralized fusion peptide was multimerized and expressed in Escherichia coli as tandem repeats to increase the production yield. Multimers of the CAP-buforin II fusion peptide were successfully expressed at high levels in E. coli as inclusion bodies. More than 100mg of pure buforin II was obtained per 11 of E. coli culture after cleaving the multimeric polypeptide with CNBr. The buforin II obtained from the recombinant E. coli had antimicrobial activity identical to that of natural buforin II. The proposed expression system can provide a cost-effective mass production method for both antimicrobial peptides and other host-lethal basic proteins.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.160-170
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• 2016

The increasing spread of antibiotic-resistant pathogens has raised the interest in alternative antimicrobial treatments. In our study, the functionally active gram-negative bacterium bacteriophage CP933 endolysin was produced in Nicotiana benthamiana plants by a combination of transient expression and vacuole targeting strategies, and its antimicrobial activity was investigated. Expression of the cp933 gene in E. coli led to growth inhibition and lysis of the host cells or production of trace amounts of CP933. Cytoplasmic expression of the cp933 gene in plants using Potato virus X-based transient expression vectors (pP2C2S and pGR107) resulted in death of the apical portion of experimental plants. To protect plants against the toxic effects of the CP933 protein, the cp933 coding region was fused at its Nterminus to an N-terminal signal peptide from the potato proteinase inhibitor I to direct CP933 to the delta-type vacuoles. Plants producing the CP933 fusion protein did not exhibit the severe toxic effects seen with the unfused protein and the level of expression was 0.16 mg/g of plant tissue. Antimicrobial assays revealed that, in contrast to gram-negative bacterium E. coli (BL21(DE3)), the gram-positive plant pathogenic bacterium Clavibacter michiganensis was more susceptible to the plant-produced CP933, showing 18% growth inhibition. The results of our experiments demonstrate that the combination of transient expression and protein targeting to the delta vacuoles is a promising approach to produce functionally active proteins that exhibit toxicity when expressed in plant cells.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1405-1412
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• 2014

Lysozyme is a protein found in egg white, tears, saliva, and other secretions. As a marketable natural alternative to preservatives, lysozyme can act as a natural antibiotic. In this study, we have isolated Bacillus licheniformis TIB320 from soil, which contains a lysozyme gene with various features. We have cloned and expressed the lysozyme in E. coli. The antimicrobial activity of the lysozyme showed that it had a broad antimicrobial spectrum against several standard strains. The lysozyme could maintain efficient activities in a pH range between 3 and 9 and from $20^{\circ}C$ to $60^{\circ}C$, respectively. The lysozyme was resistant to pepsin and trypsin to some extent at $40^{\circ}C$. Production of the lysozyme was optimized by using various expression strategies in B. subtilis WB800. The lysozyme from B. licheniformis TIB320 will be promising as a food or feed additive.

• Journal of Dairy Science and Biotechnology
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• v.25 no.2
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• pp.17-20
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• 2007

Bovine lactoferricin(LFcin B) is a peptide of 25 amino acids that originated from the N terminus of bovine lactoferrin, and is characterized as having potent antimicrobial activity against bacteria, fungi, protozoa and viruses. But, direct expression of Lfcin B is lethal to Escherichia coli. For the efficient production of Lfcin B in microorganism, we developed an expression system in which the gene for cationic Lfcin B was fused to an anionic peptide gene, and successfully expressed the concatemeric fusion gene in E. coli. The purified recombinant Lfcin B was found to have antimicrobial activity, as chemically synthesized Lfcin B peptide does.

• 한국유가공학회:학술대회논문집
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• 2007.09a
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• pp.13-20
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• 2007

Bovine lactoferricin(LFcin B) is a peptide of 25 amino acids that originated from the N terminus of bovine lactoferrin, and is characterized as having potent antimicrobial activity against bacteria, fungi, protozoa and viruses. But, direct expression of Lfcin B is lethal to Escherichia coli. For the efficient production of Lfcin B in E. coli, we developed an expression system in which the gene for cationic Lfcin B was fused to an anionic peptide gene, and successfully expressed the concatemeric fusion gene in E. coli. The purified recombinant Lfcin B was found to have antimicrobial activity, as the native Lfcin B peptide does.