• International Journal of Oral Biology
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• v.32 no.3
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• pp.103-107
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• 2007

We hypothesized that plaque-associated bacteria may have a role in maintenance of alveolar bone. To test it, immortalized gingival epithelial HOK-16B cells were co-cultured with live or lysed eight plaque bacterial species and the expression levels of bone morphogenetic protein (BMP)-2 and -4 were examined by real time reverse transcription-polymerase chain reaction. Un-stimulated HOK-16B cells expressed both BMP-2 and -4. Co-culture with plaque bacterial lysates had significant effects on the level of BMP-2 but not on that of BMP-4. Five species including Streptococcus sanguinis, S. gordonii, Veillonella atypica, Porphyromonas gingivalis, and Treponema denticola substantially up-regulated the level of BMP-2. In contrary to the upregulatory effect of lysate, live T. denticola suppressed the expression of BMP-2. In addition, in vitro osteoblastic differentiation assay using C2C12 cells and the conditioned medium of HOK-16B cells confirmed the production of BMPs by gingival epithelial cells and the modulation of BMP expression by the lysates of S. sanguinis and T. denticola. In conclusion, we have shown that plaque bacteria can regulate the expression of BMP-2 by gingival epithelial cells, the physiologic meaning of which needs further investigation.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1728-1735
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• 2014

Scrub typhus, caused by infection with Orientia tsutsugamushi, is a mite-borne zoonotic disease endemic to the Asian-Pacific region. In Korea, the incidence of this disease has increased with climate changes, and over 10,000 cases of infection were reported in 2013. Although this infection is treatable with antibiotics such as doxycycline and azithromycin, an effective prophylactic vaccine against O. tsutsugamushi would be more desirable for preventing scrub typhus in endemic areas. In this study, we investigated the 56-kDa type-specific antigen (TSA56), which is a major outer membrane protein of O. tsutsugamushi, as a vaccine candidate. Intranasal immunization of recombinant TSA56 (rec56) induced a higher level of TSA56-specific IgG than that induced by intramuscular immunization of tsa56-expressing DNA (p56). Both types of immunization induced a cell-mediated immune response to TSA56, as demonstrated by the splenic cell proliferation assay. Mice immunized with p56, followed by rec56 plus heat-labile enterotoxin B subunit from E. coli, had a stronger protection from a homologous challenge with the O. tsutsugamushi Boryong strain than with other combinations. Our preliminary results suggest that an effective human vaccine for scrub typhus can include either recombinant TSA56 protein or tsa56-expressing DNA, and provide the basis for further studies to optimize vaccine performance using additional antigens or different adjuvants.

• Biomedical Science Letters
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• v.12 no.4
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• pp.329-335
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• 2006

Echinostoma hortense (E. hortense) is an intestinal trematode with the highest infection rate in South Korea. However, the immune response against E. hortense infection has not been explained well. In the present study, we investigated the effect of treatment with cyclosporin A (CsA) and histamine receptor antagonists on the cytokine expression and mucosal goblet cells in E. hortense-infected C3H/HeN mice. The alteration of cytokine mRNA expression ($TNF-{\alpha},\;IL-l{\beta},\;IL-4\;and\;IL-5$), intestinal worm recovery rate and goblet cell responses were measured weekly from 0 to 5 weeks post-infection (P.I.) in the control and the following three drug-treated groups: CsA, hydroxyzine and cimetidine. Compared with the control group, the expression of $TNF-{\alpha}$, IL-4 and IL-5 mRNAs decreased in the CsA- and hydroxyzine-treated groups, but only IL-4 mRNA expression did in the cimetidine-treated group. Worm recovery rate was significantly increased in the drug-treated groups. Mucosal goblet cells and their mucin response significantly decreased in the CsA-treated group (P<0.01), but significantly increased in the cimetidine- (P<0.05) and hydroxyzine- (P<0.01) treated groups. These data suggest that CsA treatment inhibits production of Th1- and Th2-type cytokines which are necessary for the worm expulsion. Histamine receptor increases goblet cells and their mucin activation, although it remains to be elucidated whether it directly affects the worm expulsion period of E. hortense in C3H/HeN mice.

• The Journal of Korean Society of Virology
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• v.29 no.4
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• pp.201-209
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• 1999

Results of the studies on the morphologic and molecular biologic characteristics of Hantaan virus (HTNV), one of the etiologic agents of Hemorrhagic fever with renal syndrome (HFRS), revealed that HTNV was a member of Family Bunyaviridae and its RNA divided into three segments. And the nucleotide sequences of these segments also were known and the differences in nucleotide sequences of HTNV from other members of genus Hantavirus were clearly evaluated. But the morphorgenesis, pathogenesis of HFRS and the replication time had not been clearly determined. In this study, to estimate the replication time of HTNV in Vero E-6 cells, Vero cells were infected with HTNV 76/118 strain, and cells were harvested from two hours post-infection up to 24 hours at two hours-intervals. Harvested cells were treated with ordinary techniques for electron microscopy and immune-electron microscopy. And then thin sections were observed under transmission electron microscope. HTNV particles were not found in the cytoplasm and in the extracellular space between $2{\sim}8$ hours after inoculation of virus, but virus particles were observed in extracellular space near the cell membrane of Vero-E6 cells 10 hours after infection. In immune electron microscopy, mature HTNV particles in extracellular spaces and immature virus labelled with gold particles in the cytoplasm of Vero E-6 cell 10 hours after infection of HTNV could be seen. This results suggest that the replication time of HTNV might be about 10 hours.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.125-130
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• 2013

Influenza viruses cause significant morbidity and mortality in humans through epidemics or pandemics. Currently, two classes of anti-influenza virus drugs, M2 ion-channel inhibitors (amantadin and rimantadine) and neuraminidase inhibitors (oseltamivir and zanamivir), have been used for the treatment of the influenza virus infection. Since the resistance to these drugs has been reported, the development of a new antiviral agent is necessary. In this study, we examined the antiviral efficacy of the plant extracts against the influenza A/PR/8/34 infection. In vitro, the antiviral activities of the plant extracts were investigated using the cell-based screening. Three plant extracts, Thuja orientalis, Aster spathulifolius, and Pinus thunbergii, were shown to induce a high cell viability rate after the infection with the influenza A/PR/8/34 virus. The antiviral activity of the plant extracts also increased as a function of the concentration of the extracts and these extracts significantly reduced the visible cytopathic effect caused by virus infections. Furthermore, the treatment with T. orientalis was shown to have a stronger inhibitory effect than that with A. spathulifolius or P. thunbergii. These results may suggest that T. orientalis has anti-influenza A/PR/8/34 activity.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.70.1-70.14
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• 2023

Background: Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic and progressive granulomatous enteritis and economic losses in dairy cattle in subclinical stages. Subclinical infection in cattle can be detected using serum MAP antibody enzyme-linked immunosorbent assay (ELISA) and fecal polymerase chain reaction (PCR) tests. Objectives: To investigate the differences in blood parameters, according to the detection of MAP using serum antibody ELISA and fecal PCR tests. Methods: We divided 33 subclinically infected adult cattle into three groups: seronegative and fecal-positive (SNFP, n = 5), seropositive and fecal-negative (SPFN, n = 10), and seropositive and fecal-positive (SPFP, n = 18). Hematological and serum biochemical analyses were performed. Results: Although the cows were clinically healthy without any manifestations, the SNFP and SPFP groups had higher platelet counts, mean platelet volumes, plateletcrit, lactate dehydrogenase levels, lactate levels, and calcium levels but lower mean corpuscular volume concentration than the SPFN group (p < 0.017). The red blood cell count, hematocrit, monocyte count, glucose level, and calprotectin level were different according to the detection method (p < 0.05). The SNFP and SPFP groups had higher red blood cell counts, hematocrit and calprotectin levels, but lower monocyte counts and glucose levels than the SPFN group, although there were no significant differences (p > 0.017). Conclusions: The cows with fecal-positive MAP status had different blood parameters from those with fecal-negative MAP status, although they were subclinically infected. These findings provide new insights into understanding the mechanism of MAP infection in subclinically infected cattle.

• Biomedical Science Letters
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• v.18 no.2
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• pp.160-164
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• 2012

The baculovirus/insect cell expression system is of great value for the large-scale production of normal and mutant mammalian passive glucose-transport proteins heterologously for structural and functional studies. In most mammalian cells that express HepG2, this transporter isoform is predominantly located at the cell surface. However, it had been reported that heterologous expression of other membrane proteins using the baculovirus system induced highly vacuolated cytoplasmic membranes. Therefore, how a cell responds to the synthesis of large amounts of a glycoprotein could be an interesting area for investigation. In order to examine the subcellular location of the human HepG2 transport proteins when expressed in insect cells, immunofluorescence studies were carried out. Insect cells were infected with the recombinant baculovirus AcNPVHIS-GT or with wild-type virus at a MOI of 5, or were not exposed to viral infection. A high level of fluorescence displayed in cells infected with the recombinant virus indicated that transporters are expressed abundantly and present on the surface of infected Sf21 cells. The evidence for the specificity of the immunostaining was strengthened by the negative results shown in the negative controls. Distribution of the transporter protein expressed in insect cells was further revealed by making a series of optical sections through an AcNPVHIS-GT-infected cell using a confocal microscope, which permits optical sectioning of cell sample. These sections displayed intense cytoplasmic immunofluorecence surrounding the region occupied by the enlarged nucleus, indicating that the expressed protein was present not only at the cell surface but also throughout the cytoplasmic membranous structures.

• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.501-505
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• 2021

The pathogenic free-living amoeba Naegleria fowleri causes primary amoebic meningoencephalitis, a fatal infection, by penetrating the nasal mucosa and migrating to the brain via the olfactory nerves. N. fowleri can induce host cell death via lytic necrosis. Similar to phosphorylation, O-linked β-N-acetylglucosamine (O-GlcNAc) glycosylation (O-GlcNAcylation) is involved in various cell-signaling processes, including apoptosis and proliferation, with O-GlcNAc addition and removal regulated by O-GlcNAc transferase and O-GlcNAcase (OGA), respectively. However, the detailed mechanism of host cell death induced by N. fowleri is unknown. In this study, we investigated whether N. fowleri can induce the modulation of O-GlcNAcylated proteins during cell death in Jurkat T cells. Co-incubation with live N. fowleri trophozoites increased DNA fragmentation. In addition, incubation with N. fowleri induced a dramatic reduction in O-GlcNAcylated protein levels in 30 min. Moreover, pretreatment of Jurkat T cells with the OGA inhibitor PUGNAc prevented N. fowleri-induced O-deGlcNAcylation and DNA fragmentation. These results suggest that O-deGlcNAcylation is an important signaling process that occurs during Jurkat T cell death induced by N. fowleri.

• Parasites, Hosts and Diseases
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• v.50 no.1
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• pp.7-13
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• 2012

$Toxoplasma$ $gondii$ can modulate host cell gene expression; however, determining gene expression levels in intermediate hosts after $T.$ $gondii$ infection is not known much. We selected 5 genes ($ALDH1A2$, $BEX2$, $CCL3$, $EGR2$ and $PLAU$) and compared the mRNA expression levels in the spleen, liver, lung and small intestine of genetically different mice infected with $T.$ $gondii$. ALDH1A2 mRNA expressions of both mouse strains were markedly increased at day 1-4 postinfection (PI) and then decreased, and its expressions in the spleen and lung were significantly higher in C57BL/6 mice than those of BALB/c mice. BEX2 and CCR3 mRNA expressions of both mouse strains were significantly increased from day 7 PI and peaked at day 15-30 PI ($P$<0.05), especially high in the spleen liver or small intestine of C57BL/6 mice. EGR2 and PLAU mRNA expressions of both mouse strains were significantly increased after infection, especially high in the spleen and liver. However, their expression patterns were varied depending on the tissue and mouse strain. Taken together, $T.$ $gondii$-susceptible C57BL/6 mice expressed higher levels of these 5 genes than did $T.$ $gondii$-resistant BALB/c mice, particularly in the spleen and liver. And ALDH1A2 and PLAU expressions were increased acutely, whereas BEX2, CCL3 and EGR2 expressions were increased lately. Thus, these demonstrate that host genetic factors exert a strong impact on the expression of these 5 genes and their expression patterns were varied depending on the gene or tissue.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.211-226
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• 1986

To understand the pathogenesis of anicteric leptospirosis with severe pulmonary hemorrhage occured in Korea, the microbiological and pathological features were observed in the experimentally induced leptospirosis in guinea pigs infected with a virulent strain of Leptospira interrogans isolated from the patient at Wonju, Korea, and the results are summarized as follows. 1. The main pathological features were widespread hemorrhages, especially affecting lung, skeletal muscles, retroperitoneal and perirenal adipose tissues. The hemorrhages accompanied inflammatory process especially of vasculitic pattern as well as occasional coagulation necrosis in the liver, skeletal muscle, and myocardium. The main inflammatory cells were of plasma cell even in the fairly early stage of the infection. 2. Those pathologic changes were more exaggerated in the inoculation site. 3. Within 144 hours of infection, the longer the infection time, the more antigens were observed in the tissues, and the severer the pathologic changes. 4. Leptospiral antigens were detected at first by indirect immunofluorescent and immunoperoxidase technics. As the infection time extended, the antigens were observed in all of the tissues examined except in the skeletal muscle. The shape of the antigens was spiral or thread-like within 72 hours of infection. As the infection progressed, they became fragmented and granular. 5. Leptospires were detected in the blood within 144 hours of infection by darkfield microscopic examination. Thereafter, none was observed. 6. Antibody to leptospires were detected as early as 72 hours of infection. In summary, the virulent strain of L. interrogans used in this experiment induced widespread hemorrhages with inflammatory reaction especially in lung, skeletal muscles, and retroperitoneal adipose tissue. With these findings, it is suggested that the direct toxic effect of leptospires might playa great role in the pathogenesis of this infection.