• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.241-246
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• 2022

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.235-244
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• 1996

We selected the adequate cell line to be used for propagation and plaquing of R. tsutsugamushi in laboratory and identified R. tsutsugamushi serotype cultured in LuMA cells by nested PCR. As in this study, we concluded that. 1. LuMA cell was suitable for the study of the biology of rickettsiae-host cell interaction. 2. The plaque-forming unit (PFU) per ml of R. tsutsugamushi Karp strain propagated in embryonated egg yolk sacs was $10^{8.8}$ and the PFU/ml of Gilliam strain was $10^{7.1}$. 3. The rate and extent of cytopathic changes depended on the PFU titer of R. tsutsugamushi. 4. PCR with nested primer pairs was useful for identification of R. tsutsugamushi serotype cultured in human embryonic lung cells.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.1
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• pp.42-46
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• 2009

Unlike most bacteria, Treponema pallidum subspecies cannot be readily isolated or sustained in cell culture for numerous generations. In korea, two non treponemal tests are currently considered as standard; the VDRL slide test and RPR card test. These tests are based on an antigen composed of an alcoholic solution containing measured amount of cardiolipin, cholesterol, and sufficient purified lecithin to produce reactivity. The nontreponemal reagin tests measure immunoglobulin M (IgM) and IgG to lipoidal material released from damaged host cells as well as to lipoprotein-like material and possibly by cardiolipin released from the treponemes. The object of the evaluation was to evaluate the performance of the Mediace RPR kit on the automated biochemistry analyzer system as a method for screen method of syphilis as well as to identify BFP possibility. For evaluation of routine screening test, a total 2,380 specimens tested by Mediace RPR from 28th Oct, 2007 to 22th Feb, 2008. For evaluation of BFP possiblility, we measured samples which have potential BFP reaction in Syphilis test such as ANA (anti-nuclear antibody) positive (135 samples), CRP (C-reactive protein) positive (100 samples), RF (Rheumatoid factor) positive (26 samples), and other potential BFP cases (17 samples) including total 278 samples. These samples were tested quantitative test Mediace RPR with Hitachi 7600 P module. For comparison with current manual test, VDRL slide test were performed. Of these 2380 specimens, 2350 were negative, 30 were positive, and one were positive with TPHA. Both methods agreed for 2356 (98.9%) samples. Of the 30 samples showed positive results over 1.0 R.U, 6 samples showed positive results with VDRL test. Of these 6 samples, 1 samples showed positive with TPHA test. The combination of the Automated Biochemistry analyzer and VDRL test for retest can be increase efficiency of syphilis screening test.

• Journal of Korea Multimedia Society
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• v.16 no.8
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• pp.954-961
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• 2013

To enhance the efficiency of network, content-centric networking (CCN), one of future Internet architectures, allows network nodes to temporally cache transmitted contents and then to directly respond to request messages which are relevant to previously cached contents. Also, since CCN uses a hierarchical content-name, not a host identity like source/destination IP address, for request/response packet routing and CCN request message does not include requester's information for privacy protection, contents-providers/ network nodes can not identify practical requesters sending request messages. So to send back relevant contents, network nodes in CCN records both a request message and its incoming interfaces on Pending Interest Table (PIT). Then the devices refer PIT to return back a response message. If PIT is exhausted, the device can not normally handle request/response messages anymore. Hence, it is needed to detect/react attack to exhaust PIT. Hence, in this paper, we propose improved detection/reaction schemes against attacks to exhaust PIT. In practice, for fine-grained control, this proposal is applied to each incoming interface. Also, we propose the message framework to control attack traffic and evaluate the performance of our proposal.

• Journal of Periodontal and Implant Science
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• v.43 no.5
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• pp.215-220
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• 2013

Purpose: Cigarette smoking is a major risk factor in periodontal diseases. The pathogenesis of periodontal diseases may be affected by alterations of the inflammatory response by smoke. Nitric oxide (NO) is a gaseous, colorless, highly reactive, short-lived free radical with a pivotal role in the regulation of various physiological and pathological mechanisms in the body. It is important in host defense and homeostasis, on the one hand, whereas, on the other hand, it modulates the inflammatory response in periodontitis, leading to harmful effects. The aim of this study was to assess the levels of NO in both the serum and saliva of smokers and nonsmokers having chronic periodontitis and to compare them with periodontally healthy controls. Methods: Sixty subjects participated in the study and were divided into three groups: group I, healthy nonsmoking subjects; group II, nonsmoking patients with chronic periodontitis; group III, smoking patients with chronic periodontitis. Each group consisted of twenty subjects. The biochemical estimation of NO in the collected serum and in the saliva was performed using the Griess colorimetric reaction. Results: The results showed that the mean value of the salivary and serum NO was greater in group II than in group I, and also greater in group III than in group II. Conclusions: NO appears to play an important and rather complex role in the immuno-inflammatory process and in the remodeling and maintenance of osseous structures. It is therefore logical that modulation of this mediator has potential for the treatment of a number of inflammatory conditions including periodontal disease.

• Biomedical Science Letters
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• v.18 no.3
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• pp.201-209
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• 2012

Apoptosis is a physiological programmed cell death process. Tubercle bacilli inhibit apoptosis of alveolar macrophages and phagolysosome fusion. We investigated whether the Bcl-2 family anti-apoptotic member, Bfl-1/A1, plays an important role in the anti-apoptotic process during mycobacterial infection. PMA-treated human monocytoid THP-1 cells were infected with mycobacteria (H37Rv, BCG, and K-strain) at a multiplicity of infection (MOI) of 10 for 0, 1.5, 3, 6, 9, 12, 18, 24, 48, or 72 h. In addition, PMA-treated THP-1 cells were pretreated with specific inhibitors for 45 min before stimulation with mycobacteria at an MOI of 10 for 4 h. After the indicated time, the cells were subject to reverse transcription-polymerase chain reaction (RT-PCR) analysis, and a Bfl-1/A1-specific Western blot was performed. In PMA-differentiated THP-1 cells, the expression level of Bfl-1/A1 mRNA was increased by Mycobacterium tuberculosis (MTB) H37Rv infection. The mRNA level of Bfl-1/A1 peaked 3 h after MTB infection, then declined gradually until 9 h. However, Bfl-1/A1 mRNA induction gradually re-increased from 24 h to 72 h after MTB infection. No difference in Bfl-1/A1 expression was detected following infection with MTB H37Rv, K-strain, or M. bovis BCG. These results were not dependent on mycobacterial virulence. Moreover, mRNA levels of other anti-apoptotic molecules (Mcl-1, Bcl-2, and Bcl-xL) were not increased after MTB H37Rv or K-strain infection. These results suggest that mycobacteria induce the innate immune host defense mechanisms that utilize Bfl-1/A1 molecules at early time points, regardless of virulence.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.2
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• pp.129-136
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• 1993

The purpose of this study is to evaluate whether the ashed tooth powder is utilized as an alternative material of the implant. For this purpose the author performed the experimental study to investigate the tissue response of sintered toothash and its histocompatibility. Bony defects to expose the body of marrow, $1{\times}1cm$ in size, were created in the right and left mandibular body of mature dog, and then the ashed tooth powders were filled in right side and the blood clot was filled in the left side as an control. The dogs were sacrificed at 4th, 7th, and 16th week after implantation and histologic examination was performed. The results of this study were obtained as follows : 1. Any inflammatory response was not noted after implanting of the ashed tooth powder during the whole experimental period. 2. At 4th week, ashed tooth powders were surrounded by mature connective tissue. And we could observe hydroxyapatite crystal structure within the ashed tooth powder. 3. At 7th week, we could observe that macrophage phagocyted the small granules of ashed tooth powders. 4. At 16th week, the union with host bone by growth of new trabeculae was observed. And there were remnants of ashed tooth power within some of new trabeculae.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1867-1876
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• 2017

Most of the biosynthetic pathways for secondary metabolites are influenced by carbon metabolism and supply of cytosolic NADPH. We engineered carbon distribution to the pentose phosphate pathway (PPP) and redesigned the host to produce high levels of NADPH and primary intermediates from the PPP. The main enzymes producing NADPH in the PPP, glucose 6-phosphate dehydrogenase (encoded by zwf1 and zwf2) and 6-phosphogluconate dehydrogenase (encoded by zwf3), were overexpressed with opc encoding a positive allosteric effector essential for Zwf activity in various combinations in Streptomyces lividans TK24. Most S. lividans transformants showed better cell growth and higher concentration of cytosolic NADPH than those of the control, and S. lividans TK24/pWHM3-Z23O2 containing zwf2+zwf3+opc2 showed the highest NADPH concentration but poor sporulation in R2YE medium. S. lividans TK24/pWHM3-Z23O2 in minimal medium showed the maximum growth (6.2 mg/ml) at day 4. Thereafter, a gradual decrease of biomass and a sharp increase of cytosolic NADPH and sedoheptulose 7-phosphate between days 2 and 4 and between days 1 and 3, respectively, were observed. Moreover, S. lividans TK24/pWHM3-Z23O2 produced 0.9 times less actinorhodin but 1.8 times more undecylprodigiosin than the control. These results suggested that the increased NADPH concentration and various intermediates from the PPP specifically triggered undecylprodigiosin biosynthesis that required many precursors and NADPH-dependent reduction reaction. This study is the first report on bespoke metabolic engineering of PPP routes especially suitable for producing secondary metabolites that need diverse primary precursors and NADPH, which is useful information for metabolic engineering in Streptomyces.

• Journal of dental hygiene science
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• v.17 no.1
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• pp.81-86
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• 2017

Bacterial infection and smoking are an important risk factors involved in the development and progression of periodontitis. However, the signaling mechanism underlying the host immune response is not fully understood in periodontal lesions. In this study, we determined the expression of janus kinase (JAK)/signal transducer and activator of transcription (STAT) on Porphyromonas gingivalis lipopolysaccharide (LPS)- and nicotine-induced cytotoxicity and the production of inflammatory mediators, using osteoblasts. The cells were cultured with 5 mM nicotine in the presence of $1{\mu}g/ml$ LPS. Cell viability was determined using MTT assay. The role of JAK on inflammatory mediator expression and production, and the regulatory mechanisms involved were assessed via enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot analysis. LPS- and nicotine synergistically induced the production of cyclooxgenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) and increased the protein expression of JAK/STAT. Treatment with an JAK inhibitor blocked the production of COX-2 and $PGE_2$ as well as the expression of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$ ($IL-1{\beta}$), and IL-6 in LPS- and nicotine-stimulated osteoblasts. These results suggest that JAK/STAT is closely related to the LPS- and nicotine-induced inflammatory effects and is likely to regulate the immune response in periodontal disease associated with dental plaque and smoking.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.33-37
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• 2002

The phosphorescence powder, $SrA1_2O_4:Eu^{2+}$, synthesized by a Polymerized Complex Method(PCM), has been compared with that by a Solid-State Reaction(SSR), and their luminescence characteristics have been studied. The PCM powders were synthesized at $900^{\circ}C$ and the SSR powders at $1200^{\circ}C$. The size of PCM powders was about $0.1{\mu}m$ and one tenth of that of the SSR powders, which was due to the lower synthesized temperature. On the other hand, residual carbon in the PCM powders decreased with an increase in the crystallinity of host lattice, which was responsible for the non-white color of the powders. Both powders showed the maximum luminescence peaks around 520nm in the wave length at room temperature. However, the peak position for the PCM powders was shifted to a slightly lower wavelength and the value of half-width of the peak was broad comparing to that of the SSR powders, and the peak intensity decreased significantly. Such a change in the luminescence characteristics was due to the large difference in size for two types of powders and partly the residual carbon in the PCM powders.