http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Byoung-Kuk Na (검색결과 118 건)
- 무료
- 기관 내 무료
- 유료
-
1996년과 1999년 경기지역 초등학교 학생들에서 유행성이하선염에 대한 면역도 조사
나병국,이주영,고운영,이진수,신구철,이주연,최보율,기모란,양병국,강춘,김우주,김지희 대한감염학회 2001 감염 Vol.33 No.3
Background : Although massive use of live attenuated mumps virus vaccines successfully reduced the incidence of mumps virus infection worldwide, mumps outbreaks have not been completely eliminated, even in vaccinated populations. In recent years, the incidence of mumps has been remarkably increased in Korea. This study was designed to evaluate the recent seroprevalence rate of mumps IgG among children in Kyonggi province at 1996 and 1999. Methods : Study population included students from 8 elementary schools in Kyonggi province. Serum samples were collected twice at 1996 and 1999 and tested for mumps-specific antibody by enzyme-linked immunosorbent assay (ELISA). We also conducted a questionnaire survey on the parents and collected the records including history of vaccination and mumps infection. Results : The seropositive rates against mumps were 89.47% and 89.74% at 1996 and 1999, respectively, and they were not significantly different when compared to age, sex, and region. Although the first vaccination rates were 92.17% and 92.25% at 1996 and 1999, respectively, the second vaccination rates were only 37.89% and 38.03% at 1996 and 1999, respectively. Infection rate showed no significant difference between vaccinated groups and nonvaccinated gropus. Seropositive rate of infected group was higher than that of noninfected group but it was not significantly different between the vaccinated and the nonvaccinated. Conclusions : This study showed the seropositive rate and vaccination against mumps in children. There were no significant relationships between vaccination and infection. Therefore, it seems likely that the vaccination is not fully protective against mumps infection. This study will be helpful for the establishment of guideline for prevention and treatment of mumps in Korea. (Korean J Infect Dis 33: 157∼164, 2001)
-
-
Na, Byoung-Kuk,Kim, Moon-Bo,Song, Chul-Yong The Microbiological Society of Korea 1996 The journal of microbiology Vol.34 No.1
The effect of the extracellular protease of Salmonella schottmulleri on human serum constituents such as immunoglobulins, hemoglobin and lysozyme and tissue constituents such as fibronectin and collagens was investigated. This protease degraded collagens (type I and III), fibronectin and serum proteins such as human hemoglobin and lysozyme. Bovine serum albumin was degraded slightly. Thus, the present study suggested the possibility that this protease is not only played an important role in invasion of S. schottmulleri by degrading the constituent proteins such as collagens and fibronectin but also induced complications observed in septicemia and chronic infections by degrading the serum proteins. This protease is also capable of degrading defence-oriented humoral proteins, immunoglobulins (IgG and IgM). Furthermore, it is toxic to HEp-2 cells. These findings clarified the possible role of Salmonella protease as a virulence factor in the pathogenesis of Salmonella infections.
-
Partial Characterization of Proteases from Culture Filtrate of Mycobacterium tuberculosis
Na, Byoung-Kuk,Song, Chul-Yong,Park, Young-Kill,Bai, Gill-Han,Ki, Sang-Jae The Microbiological Society of Korea 1996 The journal of microbiology Vol.34 No.2
Two proteases were partially characterized from culture filtrate of Mycobacterium, tuberculosis KIT110. Their molecular weights were approximately 200 and 180 kDa, respectively and they exhibited similar enzymatic characteristics. These enzymes were inhibited significantly by EDTA and to some extent by EGTA. Their activity was enhanced by $Ca^{2+}$ and $Mg^{2+}$ to some degree. However, $Cu^{2+}$ and $Ag^{2+}$ completely inhibited the enzyme activity at the concentration of 2.5 and 5 mM, respectively. The optimal pH was 7.0 and optimal temperature was around $40^{\circ}C$. These enzymes were rapidly inactivated at $80^{\circ}C$. Therefore, they were heat-labile, neutral metalloproteases. These enzymes exhibited antigenicity shown by their reacting with sera from the partients with pulmonary tuberculosis. These enzymes were able to degrade serum proteins including hemoglobin, bovine serum albumin, lysozyme and immunoglobulin G and structural matrix protein such as type I collagen. Therefore, these enzymes may be thought to contribute to tissue necrosis and pathogenesis during infection.
-
Na, Byoung-Kuk,Song, Chul-Yong The Microbiological Society of Korea 1995 The journal of microbiology Vol.33 No.3
An extracellular protease of Salmonella schottmulleri was purified from culture filtrate by using 0-75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, Ultrogel HA chromatography and Sephacryl S-200 HR molecular sieve chromatography. To measure enzyme activity, synthetic dipeptide substrate (CBZ-arg-arg-AFC) with low molecular weight was employed as substrate. The molecular weight of the purified enzyme was approximately 80 kDa when determined by gel filtration on Sephacryl S-200 HR and 73 kDa when estimated by SDS-PAGE. The isoelectric point was 5.45. The activity of the purified enzyme was inhibited by metal chelating agesnts such as EDTA and 1.10-phenanthroline. The divalent cations, such as Ca$\^$2+/, Zn$\^$2+/, Fe$\^$2+/, Mg$\^$2+/ enhanced its activity. These results suggested that it was a metalloprotease. It had a narrow pH optimum of 6.5-7.5 with a maximum at pH 7.0 and a temperature optimum of 40.deg.C. It was stable at least for 1 week at 40.deg.C and maintained its activity for 24 hours at 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium dodecyl sulfate (SDS) and was inactivated in a dose-dependent manner. However, it was resistant to Triton X-100 and the activity was enhanced to 32.3% with treatment of 0.025% Triton X-100.
-
Na, Byoung-Kuk,Kang, Jung-Mi,Kim, Tong-Soo,Sohn, Woon-Mok Elsevier 2007 Experimental parasitology Vol.116 No.4
<P><B>Abstract</B></P><P>Malaria parasite glutathione <I>S</I>-transferases (GSTs) are postulated to be essential for parasite survival by protecting the parasite against oxidative stress and buffering the detoxification of heme-binding compounds; therefore, GSTs are considered potential targets for drug development. In this study, we identified a <I>Plasmodium vivax</I> gene encoding GST (<I>PvGST</I>) and characterized the biochemical properties of the recombinant enzyme. The <I>PvGST</I> contained 618 bp that encoded 205 amino acids and shared a significant degree of sequence identity with GSTs from other <I>Plasmodium</I> species. The recombinant homodimeric enzyme had an approximate molecular mass of 50kDa and exhibited GSH-conjugating and GSH–peroxidase activities towards various model substrates. The optimal pH for recombinant PvGST (rPvGST) activity was pH 8.0, and the enzyme was moderately unstable at 37°C. The <I>K</I><SUB>m</SUB> values of rPvGST with respect to GSH and CDNB were 0.17±0.09 and 2.1±0.4mM, respectively. The significant sequence homology and similar biochemical properties of PvGST and <I>Plasmodium falciparum</I> GST (PfGST) indicate that they may have similar molecular structures. This information may be useful for the design of specific inhibitors for plasmodial GSTs as potential antimalarial drugs.</P>
-
Purification and Characterization of Extracellular Aspartic Proteinase of Candida albicans
Na, Byoung-Kuk,Lee, Seong-Il,Kim, Sin-Ok,Park, Young-Kil,Bai, Gill-Han,Kim, Sang-Jae,Song, Chul-Yong The Microbiological Society of Korea 1997 The journal of microbiology Vol.35 No.2
An extracellular proteinase of Candida albicans was purified by a combination of 0~75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephacryl S-200 HR molecular sieve chromatography. Its mlecular weight was approximately 41 kDa on SDS-PAGE and isoelectric point was 4.4. The enzyme was inhibited by pepstain A. Optimum enzyme activity ranged from pH 2.0 to 3.5 with its maximum at pH 2.5 and a temperature of 45$^{\circ}C$. The addition of divalent cations, $Ca^{2+}$, Zn$^{2+}$ and $Mg^{2+}$, resulted in no significant inhibition of enzymatic activity. However, some inhibitory effects were observed by Fe$^{2+}$, Ag$^{2+}$ and Cu$^{2+}$. With BSA as substrate, an apparent $K_m$ was determined to be 7$\times$10$^{-7}$ M and $K_i$, using pepstatin A as an inhibitor, was 8.05$\times$10$^{-8}$ M. N-terminal amino acid sequence was QAVPVTLXNEQ. Degradation of BSA and fibronectin was shown but not collagen, hemoglobin, immunoglobulin G, or lysozyme. The enzyme preferred peptides with Glu and Leu at the P$_1$ position, but the enzyme activity was highly reduced when the P$_2$ position was phe or pro. This enzyme showed antigenicity against sera of patients with candidiasis.
-
Na,Byoung Kuk,Kim,Young Shun,Song,Chul Yong 中央大學校 基礎科學硏究所 1998 基礎科學硏究所 論文集 Vol.12 No.-
The pathology associated with acanthamoebiasis may be resulted, at least in part, from the extracellular proteinases of active Acanthamoeba trophozoites. The active staining using gelatin SDS-PAGE revealed that Acanthamoeba culbertsoni produced at least five extracellular proteinases, namely P1, P2, P3, P4 and P5, of molecular weights of these enzymes were approximately 90, 60, 54, 37 and 34 kDa, respectively. The optimal temperature of these proteinases was approximately 37℃, while their biological activities were maintained above 50℃. The inhibitor studies showed that P1, P2, P3 and P4 are serine proteinases while P5 is an aspartic proteinase P1, P2, P3 and P4 had a broad range of pH optimum of 6.0-10.0. P1, P2, P3 and P4 were strongly inhibited by ZnCl₂, CuSO₄and FeSO₄. P5 had an optimum at pH 4.0 and was inhibited by CuSO₄. The excretory and secretory products of A. culbertsoni were able to degrade collagen, laminin, plasminogen, fibrinogen, fibronectin, hemoglobin and rabbit corneal extract, but not immunoglobulin A and immunoglobulin G and exhibited cytotoxicity against HEp-2 cells and HEK cells. These results suggest that the extracellular proteinases of A. culbertsoni play an important role in acanthamoebal pathogenesis.
-
Biochemical Properties of a Novel Cysteine Protease of <i>Plasmodium vivax</i> , Vivapain-4
Na, Byoung-Kuk,Bae, Young-An,Zo, Young-Gun,Choe, Youngchool,Kim, Seon-Hee,Desai, Prashant V.,Avery, Mitchell A.,Craik, Charles S.,Kim, Tong-Soo,Rosenthal, Philip J.,Kong, Yoon Public Library of Science 2010 PLoS neglected tropical diseases Vol.4 No.10
<▼1><P><B>Background</B></P><P>Multiple cysteine proteases of malaria parasites are required for maintenance of parasite metabolic homeostasis and egress from the host erythrocyte. In <I>Plasmodium falciparum</I> these proteases appear to mediate the processing of hemoglobin and aspartic proteases (plasmepsins) in the acidic food vacuole and the hydrolysis of erythrocyte structural proteins at neutral pH. Two cysteine proteases, vivapain (VX)-2 and VX-3 have been characterized in <I>P. vivax</I>, but comprehensive studies of <I>P. vivax</I> cysteine proteases remain elusive.</P><P><B>Findings</B></P><P>We characterized a novel cysteine protease of <I>P. vivax</I>, VX-4, of which orthologs appears to have evolved differentially in primate plasmodia with strong cladistic affinity toward those of rodent <I>Plasmodium</I>. Recombinant VX-4 demonstrated dual substrate specificity depending on the surrounding micro-environmental pH. Its hydrolyzing activity against benzyloxycarbonyl-Leu-Arg-4-methyl-coumaryl-7-amide (Z-Leu-Arg-MCA) and Z-Phe-Arg-MCA was highest at acidic pH (5.5), whereas that against Z-Arg-Arg-MCA was maximal at neutral pH (6.5–7.5). VX-4 preferred positively charged amino acids and Gln at the P1 position, with less strict specificity at P3 and P4. P2 preferences depended on pH (Leu at pH 5.5 and Arg at pH 7.5). Three amino acids that delineate the S2 pocket were substituted in VX-4 compared to VX-2 and VX-3 (Ala90, Gly157 and Glu180). Replacement of Glu180 abolished activity against Z-Arg-Arg-MCA at neutral pH, indicating the importance of this amino acid in the pH-dependent substrate preference. VX-4 was localized in the food vacuoles and cytoplasm of the erythrocytic stage of <I>P. vivax</I>. VX-4 showed maximal activity against actin at neutral pH, and that against <I>P. vivax</I> plasmepsin 4 and hemoglobin was detected at neutral/acidic and acidic pH, respectively.</P><P><B>Conclusion</B></P><P>VX-4 demonstrates pH-dependent substrate switching, which might offer an efficient mechanism for the specific cleavage of different substrates in different intracellular environments. VX-4 might function as a hemoglobinase in the acidic parasite food vacuole, a maturase of <I>P. vivax</I> plasmepsin 4 at neutral or acidic pH, and a cytoskeleton-degrading protease in the neutral erythrocyte cytosol.</P></▼1><▼2><P><B>Author Summary</B></P><P><I>Plasmodium vivax</I> affects hundreds of millions each year and results in severe morbidity and mortality. Plasmodial cysteine proteases (CPs) play crucial roles during the progression of malaria since inhibition of these molecules impairs parasite growth. These CPs might be targeted for new antimalarial drugs. We characterized a novel <I>P. vivax</I> CP, vivapain-4 (VX-4), which appeared to evolve differentially among primate <I>Plasmodium</I> species. VX-4 showed highly unique substrate preference depending on surrounding micro-environmental pH. It effectively hydrolyzed benzyloxycarbonyl-Leu-Arg-4-methyl-coumaryl-7-amide (Z-Leu-Arg-MCA) and Z-Phe-Arg-MCA at acidic pH and Z-Arg-Arg-MCA at neutral pH. Three amino acids (Ala90, Gly157 and Glu180) that delineate the S2 pocket were found to be substituted in VX-4. Alteration of Glu180 abolished hydrolytic activity against Z-Arg-Arg-MCA at neutral pH, indicating Glu180 is intimately involved in the pH-dependent substrate preference. VX-4 hydrolyzed actin at neutral pH and hemoglobin at acidic pH, and participated in plasmepsin 4 activation at neutral/acidic pH. VX-4 was localized in the food vacuoles and cytoplasm of the erythrocytic stage of <I>P. vivax</I>. The differential substrate preferences depending on pH suggested a highly efficient mechanism to enlarge biological implications of VX-4, including hemoglobin degradation, maturation of plasmepsin, and remodeling of the parasite architecture during growth and development of <I>P. vivax</I>.</P></▼2>
-
DBpia연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
