• Journal of Microbiology and Biotechnology
• /
• v.12 no.2
• /
• pp.249-257
• /
• 2002

Pseudomonas fluorescens GL20 is a plant growth-promoting rhizobacterium that produces a large amount of hydroxamate siderophore under iron-limited conditions. The strain GL20 considerably inhibited the spore germination and hyphal growth of a plant pathogenic fungus, Fusarium solani, when iron was limited, significantly suppressed the root-rot disease on beans caused by F. solani, and enhanced the plant growth. The mechanism for the beneficial effect of strain GL20 on the disease suppression was due to the siderophore production, evidenced by mutant strains derived from the strain. Analysis of the outer membrane protein profile revealed that the growth of strain GL20 induced the synthesis of specific iron-regulated outer membrane proteins with molecular masses of 85- and 90 kDa as the high-affinity receptors for the ferric siderophore. In addition, a cross-feeding assay revealed the presence of multiple inducible receptors for heterologous siderophores in the strain. In order to induce increased efficacy and potential in biological control of plant disease, a siderophore-overproducing mutant, GL20-S207, was prepared by NTG mutagenesis. The mutant GL20-S207 produced nearly 2.3 times more siderophore than the parent strain. In pot trials of beans with F. solani, the mutant increased plant growth up to 1.5 times compared with that of the parent strain. These results suggest that the plant growth-promoting P. fluorescens GL20 and the genetically bred P. fluorescens GL20-S207 can play an important role in the biological control of soil-borne plant diseases in the rhizosphere.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.5
• /
• pp.1508-1521
• /
• 2015

Vibrio harveyi is a pathogenic marine bacterium causing systemic symptoms resulting in mass mortalities in fishes and shrimps in aquaculture. Outer membrane proteins(OMPs) are related to the pathogenicity and thus good targets for diagnosis and vaccination for Gram negative bacteria. Recently vaccination strategies using the OMPs have been suggested to control vibriosis in several fish species. In this study, we have isolated V. harveyi from diseased marine fishes from different regions of Korea and investigated genetic variations of four OMP genes including OmpK, OmpU, OmpV and OmpW. Consequently, OmpK and U genes could be divided into 3 subgroups of type I, II, III and type A, B, C, respectively, without any correlation with geographical regions and species while OmpV and W were highly homologous. OmpW gene of V. harveyi FP4138 was fully sequenced and predicted the deduced amino acid sequence to form ${\beta}-barrel$ with hydrophobic channel. Indeed, the immunogenicity of recombinant OmpW produced in Escherichia coli was assessed by vaccinating flounder. As a result, the high antibody response with antibody titer of $4.2{\pm}0.7$ and protection with relative percent survival of 60% against artificial infection of V. harveyi were demonstrated. This result indicates that OmpW is a virulence related factor and it can be a vaccine candidate to prevent a high mortality caused by V. harveyi infection in olive flounder, Paralichthys olivaceus.

• Food Science of Animal Resources
• /
• v.33 no.2
• /
• pp.281-286
• /
• 2013

Salmonella Gallinarum (SG) is known as an important pathogen that causes fowl typhoid in chickens. To investigate SG outer-membrane proteins (OMPs) as a vaccine candidate, we used proteomic mapping and database analysis techniques with extracted OMPs. Also, extracted OMPs were evaluated in several aspects to their safety, immune response in their host and protective effects. Our research has established a proteomic map and database of immunogenic SG-OMPs used as inactive vaccine against salmonellosis in chickens. A total of 22 spots were detected by 2-dimensional gel electrophoresis and immunogenic protein analysis. Eight spots were identified by Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass spectrometry (MALDI-TOF-MS) and peptide mass fingerprinting (PMF) and categorized into four different types of proteins. Among these proteins, OmpA is considered to be an immunogenic protein and involved in the hosts' immune system. To estimate the minimum safety dose in chickens, 35 brown layers were immunized with various concentrations of OMPs, respectively. Consequently, all chickens immunized with more than a $50{\mu}g$ dose were protected against challenges. Moreover, intramuscular administration of OMPs to chickens was more effective compared to subcutaneous administration. These results suggest that the adjuvanted SG-OMP vaccine not only induces both the humoral and cellular immune response in the host but also highly protects the hosts' exposed to virulent SG with $50{\mu}g$ OMPs extracted by our method.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.419-424
• /
• 2014

The pro-apoptotic BCL-2 family protein BID activates BAK and/or BAX, which form oligomeric pores in the mitochondrial outer membrane. This results in the release of cytochrome c into the cytoplasm, initiating the apoptotic cascade. Here, we utilized liposomes encapsulating sulfo-rhodamine at a controlled temperature to improve upon a previously reported assay system with enhanced sensitivity and specificity for measuring membrane permeabilization by BID-dependent BAK activation. BAK activation was inhibited by BCL-$X_L$ protein but not by a mutant protein with impaired anti-apoptotic activity. With the assay system, we screened a chemical library and identified several compounds including trifluoperazine, a mitochondrial apoptosis-induced channel blocker. It inhibited BAK activation by direct binding to BAK and blocking the oligomerization of BAK.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.11
• /
• pp.1835-1841
• /
• 2015

A cell surface display system for heterologous expression of the multifunctional cellulase, CelEx-BR12, in Escherichia coli was developed using truncated E. coli outer membrane protein C (OmpC) as an anchor motif. Cell surface expression of CelEx-BR12 cellulase in E. coli harboring OmpC-fused CelEx-BR12, designated MC4100 (pTOCBR12), was confirmed by fluorescence-activated cell sorting and analysis of outer membrane fractions by western blotting, which verified the expected molecular mass of OmpC-fused CelEx-BR12 (~72 kDa). Functional evidence for exocellulase activity was provided by enzymatic assays of whole cells and outer membrane protein fractions from E. coli MC4100 (pTOCBR12). The stability of E. coli MC4100 (pTOCBR12) cellulase activity was tested by carrying out repeated reaction cycles, which demonstrated the reusability of recombinant cells. Finally, we showed that recombinant E. coli cells displaying the CelEx-BR12 enzyme on the cell surface were capable of growth using carboxymethyl cellulose as the sole carbon source.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.2
• /
• pp.288-295
• /
• 2015

Salmonella enterica serovar Enteritidis is the predominant agent causing salmonellosis in chickens and other domestic animals. In an attempt to identify antigenic S. Enteritidis outer membrane proteins (OMPs) that may be useful for subunit vaccine development, we established a proteomic map and database of antigenic S. Enteritidis OMPs. In total, 351 and 301 spots respectively from S. Enteritidis strain 270 and strain 350 were detected by two-dimensional gel electrophoresis. Fifty-one antigen-reactive spots were detected by antisera on two-dimensional immunoblots and identified as 12 specific proteins by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. OmpA and DNA starvation/stationary phase protection protein (Dps) were the most abundant proteins among the identified OMPs, comprising 22 and 12 protein species, respectively. Interestingly, we found that the Dps of S. Enteritidis is also antigenic. OmpW was also verified to have high antigenicity. These results show that OmpA, Dps, and possibly OmpW are antigenic proteins. This study provides new insights into our understanding of the immunogenic characteristics of S. Enteritidis OMPs.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2007.05a
• /
• pp.107-108
• /
• 2007

• Biomedical Science Letters
• /
• v.17 no.3
• /
• pp.173-176
• /
• 2011

Free-living Acanthamoeba are eukaryotic protozoan organisms that are widely distributed in the air, water, etc such as environment. Acanthamoeba ingest the Escherichia coli which will replicate in cytoplasm of Acanthamoeba. Bacterial pathogenicity or virulence is one of important determinant factors to survive in free-living Acanthamoeba and otherwise Acanthamoebic pathogenicity is also an important factor for their interactions. Bacterial association with pathogenic strain of Acanthamoeba T1 and T4 was lower about two times than non-pathogenic T7. Bacterial invasion percentages into T1 were higher about three times than T7 but bacterial survival in T7 was increased as T1. The capsule-deletion mutant exhibited limited ability for invasion/uptake by and survival inside pathogenic Acanthamoeba T4. E. coli-outer membrane protein A (OmpA) decreased bacterial association with A. castellanii by about three times and it had higher effects than lipopolysaccharides (LPS). Under favorable conditions, the mutants were not survived in Acanthamoeba up to 24 h incubation. Therefore, this review will report pathogenic and non-pathogenic Acanthamoeba strains interactions with E. coli and its several mutants, i.e., capsule, OmpA and LPS.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2005.09a
• /
• pp.83-83
• /
• 2005

• Biomolecules & Therapeutics
• /
• v.2 no.4
• /
• pp.326-330
• /
• 1994

The treatment of pseudomonal infection is a perplexed problem because of its modest susceptibility to most of the major antibiotics. A novel Pseudomonas vaccine(CFC-101) was prepared from the outer membrane protein fractions of several Pseudomonas strains. In this study, we examined CFC-101's effectiveness in both active and passive immunization models. CFC-101 in mice at 0.2 mg/kg, i.p., given three times at two-day intervals, completely prevented the death caused by Pseudomonas aeruginosa. Antibody titer, in accordance with the protective effect in this active immunization, was elevated to its peak level following three consecutive administrations of CFC-101. Thereafter, antibody titer stayed at a constantly high level. Each outer membrane protein fraction from the four CFC-101 producers, exhibited good cross-protective effects in mouse infection models against different Fisher types of P. aeruginosa. In the passive immunization model, 21~336 $\mu\textrm{g}$/kg of anti-rabbit IgG to CFC-101, when mice being infected with a challenge strain, prevented the Pseudomonhas-induced death up to 60%. Therefore, the preventive effect of CFC-101 was verified in both the active and passive immunization models.