• Korean Journal of Microbiology
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• v.33 no.2
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• pp.118-124
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• 1997

In the previous study(6), we constructed the CheY-OmpR hybrid, Chp, which affects the expressions of ompF and om pC genes. Here we further characterize these effects and present the regulatory mechanism based on in vivo and in vitro data. Although Chp retained the sequence-specific DNA-binding ability, it was not possible to enhance transcriptional activity, suggesting that it may act as a competitive inhibitor to OmpR. The DNA-binding affinity of Chp was not modulated by phosphorylation of its Che Y portion. Chp was able to increase ompR transcription. FurthemlOre, it was found that the wild-type OmpR also exerts the same effect, which is also eOlltrolled by changes in medium osmolarity and in EnvZ activity.

• Journal of Life Science
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• v.31 no.1
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• pp.28-36
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• 2021

Edwardsiella piscicida is a significant cause of hemorrhagic septicemia in fish and gastrointestinal infections in humans. Survival bacteria require specialized mechanisms to adapt to environmental fluctuations. Hence, to understand the mechanism through which E. piscicida senses and responds to environmental osmolarity changes, we determined the protein expression profile and physiological properties under various salinity conditions in this study. The OmpR protein is a part of the Env-ZOmpR two-component system that has been implicated in sensing salt stress in bacteria. However, the physiological role played by this protein in E. piscicida remains to be elucidated. Therefore, in this work, the function of the OmpR protein in response to salt stress was investigated. Phenotypic analysis revealed that, in the mutant, three of the biochemical phenotypes were different from the wild type, including, citrate utilization, hydrogen sulfide, and indole production. Introduction of the plasmid containing the entire ompR gene to the mutant strain returned it to its parental phenotype. The retarded growth rate also partially recovered. Furthermore, in our studies, OmpR was not found to be related to cell motility. Taken together, our results from the mutational analysis, the growth assay, MALDI-TOF MS, qRT-PCR, and the phenotype studies suggest that the OmpR of E. piscicida is implicated in osmoregulation, growth, expression of porins (ETAE_1826), virulence-related genes (EseC, EseD and EvpC), and certain genes of unknown function (ETAE_1540 and ETAE_2706).

• Molecules and Cells
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• v.26 no.1
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• pp.34-40
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• 2008

To express an increased level of recombinant Mefp1 (marine mussel adhesive protein) in soluble form, we constructed expression vectors encoding truncated OmpA signal peptide-Mefp1 fusion proteins. OmpA signal peptide (OmpASP) is the 21 residue peptide fragment of the 23 residue OmpA signal sequence cleavable by signal peptidase I. We successfully produced increased levels of soluble recombinant Mefp1 (rMefp1) with various deletions of OmpASP, and found that the increased expression was caused by the increased pI of the N-terminus of the fusion proteins (${\geq}10.55$). All the OmpA signal peptide segments of 3-21 amino acids in length had the same pI value (10.55). Our results suggest that the pI value of the truncated OmpASP ($OmpASP_{tr}$) play an important role in directional signaling for the fusion protein, but we found no evidence for the presence of a secretion enhancer in OmpASP. For practical applications, we increased the expression of soluble rMefp1 with $OmpASP_{tr}$ peptides as directional signals, and obtained rMefp1 with the native amino terminus (nN-rMefp1) using an $OmpASP_{tr}$ Xa leader sequence that contains the recognition site for Xa protease.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1173-1181
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• 2016

Salmonella spp. are gram-negative flagellated bacteria that cause a variety of diseases in humans and animals, ranging from mild gastroenteritis to severe systemic infection. To explore development of a potent vaccine against Salmonella infections, the gene encoding outer membrane protein L (ompL) was inserted into the swinepox virus (SPV) genome by homologous recombination. PCR, western blot, and immunofluorescence assays were used to verify the recombinant swinepox virus rSPV-OmpL. The immune responses and protection efficacy of rSPV-OmpL were assessed in a mouse model. Forty mice were assigned to four groups, which were immunized with rSPV-OmpL, inactive Salmonella (positive control), wild-type SPV (wtSPV; negative control), or PBS (challenge control), respectively. The OmpL-specific antibody in the rSPV-OmpL-immunized group increased dramatically and continuously over time post-vaccination, and was present at a significantly higher level than in the positive control group (p < 0.05). The concentrations of IFN-γ and IL-4, which represent Th1-type and Th2-type cytokine responses, were significantly higher (p < 0.05) in the rSPV-OmpL-vaccinated group than in the other three groups. After intraperitoneal challenge with a lethal dose of Salmonella typhimurium CVCC542, eight out of ten mice in the rSPV-OmpL-vaccinated group were protected, whereas all the mice in the negative control and challenge control groups died within 3 days. Passive immune protection assays showed that hyperimmune sera against OmpL could provide mice with effective protection against challenge from S. typhimurium. The recombinant swinepox virus rSPV-OmpL might serve as a promising vaccine against Salmonella infection.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.603-609
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• 2016

Brucellosis affects a wide range of host species, including humans and many livestock animals. Chronic infections of the disease make antibiotic treatment costly, and the current vaccine used in livestock has not been approved for human use. This study investigated the possible use of the Brucella abortus outer membrane protein A (OmpA) as a candidate subunit vaccine in an infected mouse model. The ompA gene was cloned and overexpressed, and the recombinant OmpA (rOmpA) protein fused to maltose binding protein (MBP) was purified in Escherichia coli. Immunogenicity was verified through western blotting, and mice were immunized and challenged to evaluate its protective effect. Mice treated with rOmpA exhibited induced humoral and host cell-mediated responses, with a significant increase in immunoglobulin G (IgG1 and IgG2a) and cytokine levels, especially TNF-α and IL-12, compared with the control groups treated with either MBP or PBS. In conclusion, rOmpA should be highly considered as a future subunit vaccine for brucellosis, and further studies regarding rOmpA and its protective ability are suggested.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.950-955
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• 2010

In this study, we prepared CheonJeongKiBo-Dan(7 oriental medicinal plants, 7OMP: Astragalus Membranaceus root, Panax Ginseng root, Glycyrrhiza Glabra (licorice) root, Schizandra Chinensis fruit, Polygonatum Odoratum, Rehmannia Glutinosa root, Paeonia Albiflora root) by extracting them in one reactor and studied its efficacies on skin. UV irradiation has been suggested as a major cause of photoaging in skin. In order to investigate protective effects against UV-B induced cellular damage, 7OMP was extracted with 70% ethanol and dissolved in DMSO. The protective effect was detected by MTT assay, reactive oxygen species (ROS) generation, phosphorylation of ATR and p53 in human dermal fibroblast cell system after UV-B irradiation. 7OMP reduced UV-B-induced cellular damage in HDFs cells, and inhibited ROS generation. UV-B-induced toxicity accompanying ROS production and the resultant DNA damage are responsible for activation of ATR, p53 and Bad. In this study, 7OMP hampered phosphorylations of ATR and p53 in human dermal fibroblasts. Therefore, 7OMP may be protective against UV-induced skin photoaging.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.253-263
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• 1997

To investigate the interaction of omeprazole (OMP) and meglumine (MEG), a complex was prepared by freeze-drying method in ammoniacal aqueous medium at room temperature and subjected to IR, DSC, and 1H NMR analysis. In addition, the stability of the complex was tested by accelerated stability analysis, and the dissolution rate of both powder and enteric coated was determined pellet by paddle method. The results are as follows; i) IR, DSC, and $^{1}H$ NMR studies indicate the formation of inclusion complex between OMP and MEG probably by electrostatic forces as $[OMP]\;[MEGH]^+$ form in a stoichiometric ratio (1:1) of OMP : MEG. ii) The dissolution rate of enteric coated OMP-MEG complex pellet in simulated enteric fluid was 90.6% in 10 minutes, which may satisfy the requirement for the regulation of dissolution. iii) OMP-MEG complex were decomposed according to pseudo 1st order kinetics: while the decomposition of OMP showed a rate constant $(k_{25^{\circ}C})$ of $5.13{\times}10^{-4}{\cdot}\;day^{-1}$, a half-life$(t_{1/2})$ of 1,350 days, a shelf-life$(T_{90%})$ 205 days and an activation energy of 23.53 kcal/mole. OMP-MEG complex inhibited a rate $(k_{25})$ of $2.92{\times}10^{-4}{\cdot}\;day^{-1}$, a half-life$(t_{1/2})$ of 2,373 days, a shelf-life $(T_{90%})$ of 306 days and an activation energy of 20.18 kcal/mole. iv) OMP was stabilized markedly by the formation of OMP-MEG complex between OMP and MEG, and the humidity increased the stability of OMP-MEG complex by decreasing the decomposition rate$(k_{50^{\circ}C})$ from $1.27{\times}10^{-2}{\cdot}\;day^{-1}$ at 31% R.H. to $2.54{\times}10^{-2}{\cdot}\;day^{-1}$ at 90% R.H.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.24-31
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• 2020

Five genes (mxbDM, mxcQE and mxaB) are responsible for the transcription of methanol oxidation genes in Methylobacterium strains. Among these, MxbDM and MxcQE constitute the two-component system (TCS) regulating methanol metabolism. In this study, we integrated the methanol-sensing domain of MxbD and MxcQ with the EnvZ/OmpR from Escherichia coli. The domain-swapping strategy resulted in chimeric histidine kinases (HK's) MxbDZ and MxcQZ AM1 containing recombinant E. coli. Real-time quantitative PCR was used to monitor OmpC expression mediated by the chimeric HK and response regulator (RR) OmpR. Further, an ompC promoter based fluorescent biosensor for sensing methanol was developed. GFP fluorescence was studied both qualitatively and quantitatively in response to environmental methanol. GFP measurement also confirmed ompC expression. Maximum fluorescence was observed at 0.05% methanol and 0.01% methanol using MxbDZ and MxcQZ AM1, respectively. Thus the chimeric HK containing E. coli were found to be highly sensitive to methanol, resulting in a rapid response making them an ideal sensor.

• Biomedical Science Letters
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• v.10 no.2
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• pp.153-161
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• 2004

Antibiotic resistance is often associated with the production of inner membrane proteins (for example, AcrAB/TolC efflux pump) that are capable to extrude antibiotics, detergents, dyes and organic solvents. In order to evaluate the unknown MarB function of Escherichia coli, especially focused on the function of OmpF porin, several mutants were construted by T4GT7 transduction. MarA plays a major roles in mar (multiple antibiotic resistance) phenotype with AcrAB/TolC efflux pump in E. coli K-12. Futhermore, MarA decreases OmpF porin expression via micF antisense RNA. Expression of acrAB is increased in strains containing mutation in marR, and in those carrying multicopy plasmid expressing marA. MarB protein of E. coli K-12 showed its activity at OmpF porin & TolC protein as target molecule. Some paper reported MarB positively regulates OmpF function. MarA shows mar phenotype, and MarB along with MarA show decreased MIC through OmpF function. By this experiment, MarB could decrease MIC through the OmpF porin & TolC protein as target.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.161-166
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• 2019

This study was done to characterize distribution of Rickettsia spp. in ticks in the northwestern and southwestern provinces in the Republic of Korea. A total of 2,814 ticks were collected between May and September 2009. After pooling, 284 tick DNA samples were screened for a gene of Rickettsia-specific 17-kDa protein using nested PCR (nPCR), and produced 88 nPCR positive samples. Of these positives, 75% contained 190-kDa outer membrane protein gene (ompA), 50% 120-kDa outer membrane protein gene (ompB), and 64.7% gene D (sca4). The nPCR products of ompA, ompB, and sca4 genes revealed close relatedness to Rickettsia japonica, R. heilongjiangensis, and R. monacensis. Most Rickettsia species were detected in Haemaphysalis longicornis. This tick was found a dominant vector of rickettsiae in the study regions in the Republic of Korea.