• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.610-615
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• 2017

When Shigella infect host cells, various effecter molecules are delivered into the cytoplasm of the host cell through the type III secretion system (TTSS) to facilitate their invasion process and control the host immune responses. Among these effectors, the S. flexneri effector OspF dephosphorylates mitogen-activated protein kinases and translocates itself to the nucleus, thus preventing histone H3 modification to regulate expression of proinflammatory cytokines. Despite the critical role of OspF, the mechanism by which it localizes in the nucleus has remained to be elucidated. In the present study, we identified a potential small ubiquitin-related modifier (SUMO) modification site within OspF and we demonstrated that Shigella TTSS effector OspF is conjugated with SUMO in the host cell and this modification mediates the nuclear translocation of OspF. Our results show a bacterial virulence factor can exploit host post-translational machinery to execute its intracellular trafficking.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.289-298
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• 2006

3',5'-cyclic adenosine monophosphate (cAMP) is an important molecule, which mediates diverse cellular processes. For example, it is involved in regulation of sugar uptake/catabolism, DNA replication, cell division, and motility in various acterial species. In addition, cAMP is one of the critical regulators for syntheses of virulence factors in many pathogenic bacteria. It is believed that cAMP acts as a signal for environmental changes as well as a regulatory factor for gene expressions. Therefore, intracellular concentration of cAMP is finely modulated by according to its rates of synthesis (by adenylate cyclase), excretion, and degradation (by cAMP phosphodiesterase). In the present review, we discuss the bacterial physiological characteristics governed by CAMP and the molecular mechanisms for gene regulation by cAMP. Furthermore, the effect of cAMP on phosphotransferase system is addressed.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.1032-1037
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• 2017

The poly-${\gamma}$-$\small{D}$-glutamic acid (PGA) capsule, a major virulence factor of Bacillus anthracis, provides protection of the bacterium from phagocytosis and allows its unimpeded growth in the host. We investigated crosstalk between murine natural killer (NK) cells and macrophages stimulated with the PGA capsule of Bacillus licheniformis, a surrogate of the B. anthracis capsule. PGA induced interferon-gamma production from NK cells cultured with macrophages. This effect was dependent on macrophage-derived IL-12 and cell-cell contact interaction with macrophages through NK cell receptor NKG2D and its ligand RAE-1. The results showed that PGA could enhance NK cell activation by inducing IL-12 production in macrophages and a contact-dependent crosstalk with macrophages.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.310-313
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• 2008

C. perfringens is the most important enteric clostridial pathogen of animals. C. perfringens type A has been associated with hemorrhagic enteritis in a wide lange of domestic and wild mammals. But all types of C. perfringens can be normal inhabitants of the intestine of most mammals. We have a special case that showed C. perfringens type A infection in a hippopotamus (Hippopotamus amphibius) cub at Seoul Grand Park Zoo. Male, hippopotamus cub died in 3 days after birth. Clinical features of the hippopotamus cub have showed lethargy and anorexia before death. Gross post-mortem findings of the hippopotamus were hemorrhagic enteritis of intestine. Histopathologically, ruminant stomach and intestine showed hemorrhagic lesions and the lumen of the small intestine was filled with mucoid and hemorrhagic fluid. Also, intestine and stomach of hippopotamus were distended with gas and hemorrhagic fluid. C. perfringens was isolated in culture of small intestine and the presence of C. perfringens type A was confirmed by PCR. This case indicated that C. perfringens type A could be considered as a virulence factor responsible for causing death of a newborn hippopotamus.

• Animal cells and systems
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• v.3 no.4
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• pp.399-405
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• 1999

Characteristics of the food isolates and the clinical specimens isolates of E. coli harboring virulence factor and their correlations were analyzed. The predominant serogroup were 08 and 027 in the food isolates and 06 and 018 in the clinical isolates, respectively, showing the different patterns in serogrouping between them. In the test of antibiotic susceptibility, the food isolates were resistant to cephalothin, streptomycin, tetracycline and minocycline, and the clinical isolates were resistant to ampicillin, carbenicillin, streptomycin, cephalothin, trimethoprim/sulfamethoxazole, tetracyclino and minocycline, respectively. It shows that E.coli isolated from food sources and clinical specimens might be correlated. Plasmid profile in the food and clinical isolates showed wide diversity. Especially, large sized plasmid DNA such as 60 MDa, 90 MDa and 120 MDa were observed. The plasmid DNA (60 MDa) containing a gene encoding hemolysin was found in 43% of the food isolates and 35% of the clinical isolates. To study chromosomal homology, PFGE analysis was performed, showing different restriction patterns by Xbal. This result indicates that there were no genetic correlations between the foods and the clinical isolates.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.249-255
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• 2006

Ability of iron acquisition of pathogenic microorganisms functions as a virulence factor. Candida albicans, a fungal pathogen that requires iron for growth, is susceptible to growth retardation by high-affinity iron binding proteins such as transferrin. Recently, we reported that C. albicans could utilize the heme as a part of heme-containing proteins dissociated by heme oxygenase, CaHMX1. In search of another pathway that C. albicans can use to bypass the growth regulation produced by iron limitation, this present study examined utilization of non-candidal siderophores such as Desferal and rhodotorulic acid (RA) for acquisition of inorganic iron by the fungus. C. albicans secreting no siderophores was cultured in iron-free (pretreated with apotransferrin for 24 h) (culture medium). Once growth of the yeast reached stasis from iron starvation, a siderophore was added to the culture media. Results showed that cultures containing apotransferrin within a dialysis membrane recovered growth to the level of untreated controls, whereas C. albicans yeast cells in direct contact with soluble iron-free (apo) transferrin recovered growth only partially. When static growth from iron limitation was reached, the addition of siderophore-apotransferrin complex to culture medium also permitted the yeast to recover growth from apotransferrin growth regulation. All the data show that C. albicans can utilize the non-candidal siderophores for iron acquisition under transferrin regulation as can pathogenic bacteria.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.165-168
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• 2016

Surface protein internalin (InlA) is a major virulence factor of the food-borne pathogen L. monocytogenes. It plays an important role in bacteria crossing the host's barrier by specific interaction with the cell adhesion molecule E-cadherin. Study of this protein will help to find better ways to prevent listeriosis. In this study, a monoclonal antibody against InlA was used to detect InlA. The reaction was label-free and monitored in real time with an oblique-incidence reflectivity-difference (OI-RD) technique. The kinetic constants k_on and k_off and the equilibrium dissociation constant K_d for this reaction were also obtained. These parameters indicate that the antibody is capable of detecting InlA. Additionally, the results also demonstrate the feasibility of using OI-RD for proteomics research and bacteria detection.

• Korean Journal of Veterinary Service
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• v.26 no.4
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• pp.323-328
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• 2003

A total of 419 slaughtered cattle were used to investigate the serum Ig G titers to the Mannheimia haemolytica Al whole cell and leukotoxin recognized with important virulence factor in bacterial pathogenesis. Data obtained in this study were represented with average absorbance${\pm}$standard deviation. Serum Ig G titers were detected with the ranges from 0.1 to 0.5 at 490nm. Whole cell titers were higher than leukotoxin antibody on the whole. Antibody titers of slaughtered cattle between races, ages have no significant difference but gradual decrease under aging in dairy cow for whole cell (decline mean titer from 0.29 to 0.27 according to age) was undertaken. Holstein bulls shipped from Seoul province had a significantly lower Ig G titers than those from another ones (p<0.05).

• Journal of Life Science
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• v.8 no.2
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• pp.145-157
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• 1998

We isolated 100 Vobrio sp. from marine products and sea from July to September, 1997. We attemped on purification of hemolysin produced by Vibrio sp. The growth, hemolysin production patterns by the 100 strains of Vibrio sp. showed identical, in general. V. unlnificus ys-1 produced hemolysis as the higtest titer. The optimal culture conditions for the hemolysin production by the V. vunificus ys-1 are followings; 1. Hemolysin production was optimal dering the late exponetial phage. 2. Maximal growth, hemolysin production were in heart infusion broth. 3. Maximal yields of hemolysin was obtained when the heart infusion broth had an intial pH of 8.0, 3$0^{\circ}C$, 3% NaCL. Hemolysin was purified from culture filtrate of the strain by ammonium sulfate recipitation, ion exchange and hydrophobic interaction chromatography. The results were as follows; 1. Hemogeneity of the purified hemolysin was demonstrated by revealing single band on SDS-PAGE. The molecular weight of purified hemolysin was 45KDa. 2. The absorbance rattern in ultraviolet wsa typical of those seen with most proteinb with 280nm. 3. Purified hemolysin was atable at 5$0^{\circ}C$ but 7$0^{\circ}C$ of the acivity was lost by heating for 30 min at 6$0^{\circ}C$/ Optimal temperature of purified hemolysin was 35$^{\circ}C$. 4. Purified hemolysin was stable at the pH range of 6~9, but in the less the pH5.0. above the pH 9.0, the hemolysin activity was lost completely.

• Journal of Periodontal and Implant Science
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• v.32 no.4
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• pp.745-752
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• 2002

Osteomyelitis is an exhaustive disease whose main feature is an inflammation of inner part of bone, bone marrow. In oral and maxillofacial area, we have maxillary and mandibular osteomyelitis and the latter is dominant because of its impaired blood supply. The main cause of osteomyelitis is a bacterial infection and the ways of infections are by periapical odontogenic infection, fracture, post-operative complication, and periodontal disease. The predominant etiologic factor is periapical odontogenic infection mostly caused by advanced dental caries. It is generally believed that periodontal disease could be a cause of osteomyelitis. But periodontal disease is usually confined to the alveolar bone area and not extends to the underlying bone marrow. Accordingly periodontal infection per se rarely cause produce oseomyelitis. Even though osteomyeltis could be occurred by periodontal disease, its virulence of infection is milder than periapical odontogenic infection. So it usually provokes sclerosing or hyperplastic osteomyelitis rather than suppurative type. We had a case of suppurative osteomyelitis caused by periodontal disease and treated it with periodontal and oral and maxillofacial surgical method.