• Journal of Veterinary Clinics
• /
• v.30 no.5
• /
• pp.339-345
• /
• 2013

Mitogen-activated protein kinases (MAPKs) are a family of central signaling molecules that respond to numerous stimuli and are known to participate in processes of cell survival and death. However, it is not clear on data for cell-type specific activation of MAPKs in the progression of gastric ulcer. In the present study, we assessed how MAPKs localized at various cell types during the progression of gastric ulcer induced by ibuprofen. Gastric ulcer was induced by the repeated treatment of 200 mg/kg ibuprofen with 8 hrs interval in a day. Animals were sacrificed at 24 hrs, 48 hrs, and 72 hrs after oral treatment of ibuprofen and gastric tissues were subjected to immunohistochemical and immunoblotting evaluation. Immunoreactivity of phospho-extracellular signal-regulated kinase (p-ERK) was mainly expressed at the proliferating zone of gastric mucosa in control rats. But, these signals for p-ERK were highly shifted from cells of proliferating zone to parietal cells of the basal regions 24 hrs after treatment of ibuprofen. p-ERK signal was strongly expressed in epithelial cells adjacent to ulcer margin and new capillary and infiltrated inflammatory cells within granulation tissue of the ulcer base above 48 hrs after treatment of ibuprofen. While, phospho-c-Jun $NH_2$ terminal kinase (p-JNK) was mainly localized to the nuclei of the surface epithelial cells and the glandular epithelial cells in early gastric injury. Also, p-JNK was often observed as a scattered pattern in different regions of gastric mucosa with early gastric injury. Gradually, signal of p-JNK was strongly stained in infiltrated inflammatory cells and fibroblasts within severe ulcer base. Phospho-p38 (p-p38) MAPK was observed as scattered pattern within connective tissues of gastric mucosa. Especially, p-p38 MAPK showed strong signal in infiltrated macrophages within ulcer base. These results show that each MAPK has a specific role in various cell types during the progression of gastric ulcer.

• KSBB Journal
• /
• v.25 no.2
• /
• pp.142-154
• /
• 2010

The protein-bound innerpolysaccharides (IPS) produced by suspended mycelial cultures of Inonotus obliquus have promising potentials as an effective antidiabetic as well as an immunostimulating agents. To enhance IPS production, intensive strain improvement process should be carried out using large amount of UV-mutated protoplasts. During the whole strain-screening process, the stage of solid growth-culture was found to be the most time-requiring step, thus preventing rapid screening of high-yielding producers. In order to reduce the cell growth period in the solid growth-stage, therefore, solid growth-medium was optimized using the statistical methods such as (i) Plackett-Burman and fractional factorial designs (FFD) for selecting positive medium components, and (ii) steepest ascent (SAM) and response surface (RSM) methods for determining optimum concentrations of the selected components. By adopting the medium composition recommended by the SAM experiment, significantly higher growth rate was obtained in the solid growth-cultures, as represented by about 41% larger diameter of the cell growth circle and higher mycelial density. Sequential optimization process performed using the RSM experiments finally recommended the medium composition as follows: glucose 25.61g/L, brown rice 12.53 g/L, soytone peptone 12.53 g/L, $MgSO_4$ 5.53 g/L, and agar 20 g/L. It should be noted that this composition was almost similar to the medium combinations determined by the SAM experiment, demonstrating that the SAM was very helpful in finding out the final optimum concentrations. Through the use of this optimized medium, the period for the solid growth-culture could be successfully reduced to about 8 days from the previous 15~20 days, thus enabling large and mass screening of high producers in a relatively short period.

• Korean Journal of Microbiology
• /
• v.45 no.3
• /
• pp.246-250
• /
• 2009

Retroviruses enter host cells by membrane fusion between the viral Env proteins on the virus membrane and a virus receptor on the cellular membrane. The envelope protein of the ecotropic Moloney murine leukemia virus is synthesized as a gp85 precursor and is proteolytically cleaved into an extracellular surface unit (SU) and the transmembrane protein (TM). The cytoplasmic tail (16 amino acid; R peptide) of the TM protein is further cleaved by the viral protease during virion maturation. Unlike the wild type Env protrin bearing the R peptide, R peptide-truncated Envelope induces syncytia in susceptible cells. To understand the mechanism of R peptidetruncated Env in syncytium formation, R peptide-truncated Env expressing full-length molecular clone containing EGFP in PRR (proline rich region) of Env was constructed. This molecular clone induced syncytia in transfected NIH3T3 cells, fluorescence was detected in the cytoplasm and at the plasma membrane, while the nuclei did not stain and appeared black by fluorescence microscopy. Interestingly, virions with truncated envelope produced from transfected NIH3T3 cells induced syncytia in NIH3T3 cells, but fluorescence was not detected in the same infected cells. It is believed that cell-free viruses direct the fusion of neighboring cells without infection. Our data suggests that use of EGFP-tagged envelope for monitoring syncytium is a sensitive and convenient method. We also found that virion incorporated the R peptide-truncated Env is able to induce the formation of syncytia by fusion from without.

• Journal of Chest Surgery
• /
• v.32 no.2
• /
• pp.97-107
• /
• 1999

Background: This study was designed to develop a Korean version of the heparin-coated vascular bypass shunt by using a physical dispersing technique. The safety and effectiveness of the thrombo-resistant shunt were tested in experimental animals. Material and Method: A bypass shunt model was constructed on the descending thoracic aorta of 21 adult mongrel dogs(17.5-25 kg). The animals were divided into groups of no-treatment(CONTROL group; n=3), no-treatment with systemic heparinization(HEPARIN group; n=6), Gott heparin shunt (GOTT group; n=6), or Korean heparin shunt(KIST group; n=6). Parameters observed were complete blood cell counts, coagulation profiles, kidney and liver function(BUN/Cr and AST/ ALT), and surface scanning electron microscope(SSEM) findings. Blood was sampled from the aortic blood distal to the shunt and was compared before the bypass and at 2 hours after the bypass. Result: There were no differences between the groups before the bypass. At bypass 2 hours, platelet level increased in the HEPARIN and GOTT groups(p<0.05), but there were no differences between the groups. Changes in other blood cell counts were insignificant between the groups. Activated clotting time, activated partial thromboplastin time, and thrombin time were prolonged in the HEPARIN group(p<0.05) and differences between the groups were significant(p<0.005). Prothrombin time increased in the GOTT group(p<0.05) without having any differences between the groups. Changes in fibrinogen level were insignificant between the groups. Antithrombin III levels were increased in the HEPARIN and KIST groups(p<0.05), and the inter-group differences were also significant(p<0.05). Protein C level decreased in the HEPARIN group(p<0.05) without having any differences between the groups. BUN levels increased in all groups, especially in the HEPARIN and KIST groups(p<0.05), but there were no differences between the groups. Changes of Cr, AST, and ALT levels were insignificant between the groups. SSEM findings revealed severe aggregation of platelets and other cellular elements in the CONTROL group, and the HEPARIN group showed more adherence of the cellular elements than the GOTT or KIST group. Conclusion: Above results show that the heparin-coated bypass shunts(either GOTT or KIST) can suppress thrombus formation on the surface without inducing bleeding tendencies, while systemic heparinization(HEPARIN) may not be able to block activation of the coagulation system on the surface in contact with foreign materials but increases the bleeding tendencies. We also conclude that the thrombo-resistant effects of the Korean version of heparin shunt(KIST) are similar to those of the commercialized heparin shunt(GOTT).

• Applied Microscopy
• /
• v.39 no.2
• /
• pp.117-124
• /
• 2009

Clonorchis sinensis is the most important widely distributed parasite of the human bile duct in East Asia and the most prevalent parasitic helminth in Korea. The prevalence rate of human clonorchiasis has remained at about 2.9% in Korea. C. sinensis induces dilatation of the duct, hyperplasia of the mucosa, metaplasia or neoplasia of the mucosal epithelium, periductal inflammation and fibrosis, and thickening of the ductal wall. Fibroblast are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may also contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. In this study, ultrastructural changes, the distribution of lectin receptors and actin protein in cultured SD rat bile duct fibroblast after infection of C. sinensis were observed. Experimental group had been divided into four groups: normal bile duct fibroblast cultured in basal media (G1); C. sinensis infected bile duct fibroblast cultured in basal media (G2); normal bile duct fibroblast cultured in basal media containing excretory-secretory product (ESP) (G1-1); C. sinensis infected bile duct fibroblast cultured in basal media containing ESP (G2-1). Overall, once a host is infected by C. sinensis, it affects the host to the extent that sialic acid of ductal fibroblast is increased. Number of cytoplasmic process of SD rat bile duct fibroblast was increased. Actin protein and sialic acid were located in cell surface. Fibroblast induced by C. sinensis was not recovered to normal fibroblast. The cytoplasm bulk and cytoplasmic process were increased whereas the growth rate of the fibroblast of infected SD rat was reduced rather than that of normal fibroblast. In result, it inhibits fibroblast proliferation and increases actin protein on fibroblast cytoplasm, and so causes fibroblast metamorphosis and cellular mutation.

• Radiation Oncology Journal
• /
• v.17 no.4
• /
• pp.299-306
• /
• 1999

Purpose : The human genetic disorder ataxia-telangiectasia (AT) is a multisystem disease characterized by extreme radiosensitivity. The recent identification of the gene mutated in AT, ATM, and the demonstration that it encodes a homologous domain of phosphatidylinositol 3-kinase (PI3-K), the catalytic subunit of an enzyme involved in transmitting signals from the cell surface to the nucleus, provide support for a role of this gene in signal transduction. Although ionizing radiation was known to induce c-fos transcription, nothing is known about how ATM or PKCI mediated signal transduction pathway modulates the c-fos gene transcription and gene expression. Here we have studied the effect of PKCI on radiation sensitivity and c-fos transcription in normal and AT cells. Materials and Methods: Normal (LM217) and AT (AT5BIVA) cells were transfected with PKCI expression plasmid and the overexpression and integration of PKCI was evaluated by northern blotting and polymerase chain reaction, respectively. 5 Gy of radiation was exposed to LM and AT cells transfected with PKCI expression plasmid and cells were harvested 48 hours after radiation and investigated apoptosis with TUNEL method. The c-fos transcription activity was studied by performing CAT assay of reporter gene after transfection of c-fos CAT plasmid into AT and LM cells. Results: Our results demonstrate for the first time a role of PKCI on the radiation sensitivity and c-fos expression in LM and AT cells. PKCI increased radiation induced apoptosis in LM cells but reduced apoptosis in AT cells. The basal c-fos transcription activity is 70 times lower in AT cells than that in LM cells. The c-fos transcription activity was repressed by overexpression of PKCI in LM cells but not in AT cells. After induction of c-fos by Ras protein, overexpression of PKCI repressed c-fos transcription in LM cells but not in AT cells Conclusion: Overexpression of PKCI increased radiation sensitivity and repressed c-fos transcription in LM cells but not in AT cells. The results may be a. reason of increased radiation sensitivity of AT cells. PKCI may be involved in an ionizing radiation induced signal transduction pathway responsible for radiation sensitivity and c-fos transcription. The data also provided evidence for novel transcriptional difference between LM and AT cells.

• Journal of Life Science
• /
• v.28 no.2
• /
• pp.257-264
• /
• 2018

The YrdC superfamily is a group of proteins that are highly conserved in almost all organisms sequenced so far. YrdC in Escherichia coli was suggested to be involved in ribosome biogenesis, translation termination, cold adaptation, and threonylcarbamoyl adenosine formation in tRNA. In this study, to unambiguously demonstrate that yrdC is essential in E. coli, we constructed two yrdC mutant strains of E. coli and examined their phenotypes. In the temperature-sensitive yrdC mutant strain, cell growth stopped almost immediately under nonpermissive conditions and it appeared to accumulate 16S ribosomal RNA precursors without significant accumulation of 30S ribosomal subunits. We also cloned yeast and human homologs and demonstrated that they complement the E. coli yrdC-deletion strain. By mutational study, we demonstrated that the concave surface in the middle of the YrdC protein plays an important role in E. coli, yeast, and human versions. By comparison of two yrdC-deletion strains, we also unambiguously demonstrated that yrdC is essential for viability in E. coli and that the functions of its yeast and human homologs overlap with that of E. coli YrdC.

• Microbiology and Biotechnology Letters
• /
• v.44 no.2
• /
• pp.185-193
• /
• 2016

A novel proteolytic bacterium was isolated from soil at Yeungnam University, South Korea. The strain, named FBL-1, was rod-shaped with a smooth surface. Biolog and API 50CHB test results revealed that strain FBL-1 was a Bacillus species. Based on 16S rDNA sequencing and chemotaxonomic characterization, the strain was identified as Bacillus subtilis because it had the highest homology with Bacillus subtilis subsp. subtilis NCIB 3610 (99.5%). In liquid culture at 37℃ with shaking at 200 rpm, fructose and yeast extract were found to be the best carbon and nitrogen sources, respectively, for cell growth and protease production. The highest protease activity (451.640 U/ml) was obtained when the strain was cultured in medium containing 20 g/l of fructose and 5 g/l of yeast extract. Although further studies are needed to characterize the protease and enhance its activity, the newly isolated protein-degrading B. subtilis FBL-1 can be applicable for the production of peptides and for the degradation of proteins in various industries.

• Development and Reproduction
• /
• v.7 no.1
• /
• pp.15-22
• /
• 2003

The Fas antigen (Fas) as a cell-surface receptor protein which mediates apoptosis-inducing signals plays an important role in the immune system. Expression of Fas mRNA is detected not only in lymphoid organs but also in the nonlymphoid organs. In the ovary, most of the follicles is known to undergo atreisa through apoptosis. However, the exact mechanism of atresia was not elucidated yet. Therefore, the purposes of the present study were to investigate the expression of Fas and Fas ligand in mouse ovary and to clarify the relationship between expression of Fas and Fas ligand and atresia of follicle. The result of RT-PCR demonstrated that Fas and Fas ligand mRNA was expressed in ovary, especially granulosa cells and oocytes. The immunohistochemistry showed that the granulosa cells and oocytes in growing follicles were stained for Fas and Fas ligand, but primordial follicles were not. Furthermore, Fas and Fas ligand were intensively stained in the atretic follicles As results of TUNEL staining to detect apoptotic cells in the ovaries, the number of TUNEL-positive (apoptotic) granulosa cells and oocytes increased in the atretic follicles compared to the healthy normal follicles. These results demonstrate that there is the positive relationship between expression of Fas and Fas ligand in granulosa cells and oocyies and apoptosis of them leading to atresia of follicles. It suggests that expression of Fas and Fas ligand could be associated with atresia of follicles in mouse ovary.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.33 no.3
• /
• pp.401-410
• /
• 2006

Dental caries results from localized demineralization of tooth enamel by acids of bacterial origin produced from the fermentation of dietary sugars. A group of related oral bacteria, collectively known as mutans streptococci, are implicated as the primary etiological agents of human caries. Within this group, Streptococcus mutans has been known as a causative agent for dental caries. As well as acid production yielding the demineralization of tooth enamel, adherence and colonization of S. mutans to the teeth are also important for their virulence Cell-surface fibrillar proteins, which mediate adherence to the salivary pellicle are virulence components of mutans streptococci, and primary candidates for a human caries vaccine. Here we report that the AgI/II gene from S. mutans GS-5 were cloned by PCR amplification of the bacterial chromosomal DNA and the integrity of cloned genes were confirmed by nucleotide sequencing. Sequence analyses showed the sequence alignment of 280 nucleotides between the cloned AgI/II and the reported sequence of S. mutans GS-5 showed the perfect match The cloned genes which signal nucleotide was truncated, were transferred into bacterial expression vector and the recombinant proteins were purified as His-tag fusion proteins In order to generate polyclonal antibodies against the recombinant proteins, AgI/II mr, some $100{\mu}g$ of the proteins was injected into mice three times. It can be used for an effective vaccine production to prevent dental caries caused by pathogenic S. mutans.