선택적 촉매 산화 반응에 의한 황화 수소의 제거 Ⅱ . TiO2 / SiO2 촉매 상에서 황화 수소의 선택적 산화 반응

천승우,박대원,우희철,홍성수,정종식 ( S . W . Chun,D . W . Park,H . C . Woo,S . S . Hong,J . S . Chung ) 한국공업화학회 1996 공업화학 Vol.7 No.4

본 연구는 H₂S를 TiO₂/SiO₂촉매상에서 산소와의 직접 산화 반응을 통해 원소 황의 형태로 제거하는 반응에 관한 것이다. 순수한 TiS₂Ti(SO₄)_2를 사용한 반응 실험과 순수한 TiO₂에 대한 주기적 온도 조작 실험 결과로부터 TiO₂는 황 회수 공정에서 사용되는 촉매의 비활성화의 주원인으로 알려진 sulfation이나 salfidation에 대해 매우 안정한 것으로 나타났다. TiO₂/SiO₂촉매에서 TiO₂의 담지량이 증가함에 따라 H₂S 전화율이 증가하였고, 원소 황의 선택도는 아주 소폭으로 감소하였다. 반응 실험결과 O₂/H₂S의 비가 증가할수록 원소 황의 선택도는 크게 감소하였다. 10 wt.% TiO₂/SiO₂ 촉매는 화학 양론비의 조성(H₂S=5 vol.% O₂=2.5 vol.%)의 반응물에 10 vol.%의 수증기를 첨가한 경우 활성과 선택도가 감소하였으나 여전히 80% 이상의 원소 황 수율을 유지하고 있었다. Selective catalytic oxidation of H₂S to elemental sulfur using TiO₂/SiO₂ catalysts was investigated in this study. The reaction test with pure TiS₂and Ti(SO₄)₂and cyclic temperature operation revealed that TiO₂had a good resistance to sulfation and sulfidation, which are known as the main cause of catalytic deactivation in sulfur recovery process. With the increase of TiO₂loading amount in Tio₂/SiO₂catalysts, the conversion of H₂S increased and the selectivity of elemental sulfur was very slightly decreased. As the ratio of O₂/H₂S increased, the selectivity to elemental sulfur was drastically decreased. In the presence of 10 vol.% water vapor to a stoichiometric mixture of H₂S and O₂(H₂S =5 vol.% O=2.5 vol.%), both activity and selectivity of 10 wt.% TiO₂/SiO₂catalyst are decreased, but it still showed more than 80% of sulfur yield.

Salmonella Typhi, Salmonella Typhimurium 및 Salmonella Enteritidis의 항균제 감수성 (1997)

신영학,유정식,김기상,정동준,오경수,이점규,이상원,이근영,박미선,이복권,김호훈 국립보건연구원 1998 국립보건원보 Vol.35 No.-

성장단계별 농후사료 (濃厚飼料) 급여수준이 한우 육성비육우의 (育成肥育牛) 사료효율 , 산육능력 및 육질에 미치는 영향

강수원(S . W . Kang),장선식(S . S . Jang),정연후(Y . H . Chung),신기준(K . J . Shin),손용석(Y . S . Son) 한국영양사료학회 1995 韓國營養飼料學會誌 Vol.19 No.6

VP2 capsid domain of the H-1 parvovirus determines susceptibility of human cancer cells to H-1 viral infection

Cho, I-R,Kaowinn, S,Song, J,Kim, S,Koh, S S,Kang, H-Y,Ha, N-C,Lee, K H,Jun, H-S,Chung, Y-H Nature America, Inc. 2015 Cancer gene therapy Vol.22 No.5

Although H-1 parvovirus is used as an antitumor agent, not much is known about the relationship between its specific tropism and oncolytic activity. We hypothesize that VP2, a major capsid protein of H-1 virus, determines H-1-specific tropism. To assess this, we constructed chimeric H-1 viruses expressing Kilham rat virus (KRV) capsid proteins, in their complete or partial forms. Chimeric H-1 viruses (CH1, CH2 and CH3) containing the whole KRV VP2 domain could not induce cytolysis in HeLa, A549 and Panc-1 cells. However, the other chimeric H-1 viruses (CH4 and CH5) expressing a partial KRV VP2 domain induced cytolysis. Additionally, the significant cytopathic effect caused by CH4 and CH5 infection in HeLa cells resulted from preferential viral amplification via DNA replication, RNA transcription and protein synthesis. Modeling of VP2 capsid protein showed that two variable regions (VRs) (VR0 and VR2) of H-1 VP2 protein protrude outward, because of the insertion of extra amino-acid residues, as compared with those of KRV VP2 protein. This might explain the precedence of H-1 VP2 protein over KRV in determining oncolytic activity in human cancer cells. Taking these results together, we propose that the VP2 protein of oncolytic H-1 parvovirus determines its specific tropism in human cancer cells.

Site-specific mutagenesis of yeast 2-Cys peroxiredoxin improves heat or oxidative stress tolerance by enhancing its chaperone or peroxidase function

Hong, S. H.,Lee, S. S.,Chung, J. M.,Jung, H. s.,Singh, S.,Mondal, S.,Jang, H. H.,Cho, J. Y.,Bae, H. J.,Chung, B. Y. Springer Science + Business Media 2017 Protoplasma Vol.254 No.1

<P>Yeast peroxiredoxin II (yPrxII) is an antioxidant enzyme that plays a protective role against the damage caused by reactive oxygen species (ROS) in Saccharomyces cerevisiae. This enzyme consists of 196 amino acids containing 2-Cys Prx with highly conserved two active cysteine residues at positions 48 and 171. The yPrxII has dual enzymatic functions as a peroxidase and molecular chaperone. To understand the effect of additional cysteine residues on dual functions of yPrxII, S79C-yPrxII and S109C-yPrxII, the substitution of Ser with Cys residue at 79 and 109 positions, respectively, was generated. S109C-yPrxII and S79C-yPrxII showed 3.7- and 2.7-fold higher chaperone and peroxidase activity, respectively, than the wild type (WT). The improvement in enzyme activity was found to be closely associated with structural changes in proteins. S109C-yPrxII had increased beta-sheet in its secondary structure and formed high-molecular-weight (HMW) as well as low-molecular-weight (LMW) complexes, but S79C-yPrxII formed only LMW complexes. HMW complexes predominantly exhibited a chaperone function, and LMW complexes showed a peroxidase function. In addition, transgenic yeast cells over-expressing Cys-substituted yPrxII showed greater tolerance against heat and oxidative stress compared to WT-yPrxII.</P>

Heme oxygenase-1 mediates nicotine- and lipopolysaccharide-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase in human periodontal ligament cells

Pi, S.-H.,Jeong, G.-S.,Oh, H.-W.,Kim, Y.-S.,Pae, H.-O.,Chung, H.-T.,Lee, S.-K.,Kim, E.-C. Blackwell Publishing Ltd 2010 Journal of periodontal research Vol.45 No.2

<P><I>Pi S-H, Jeong G-S, Oh H-W, Kim Y-S, Pae H-O, Chung H-T, Lee S-K, Kim E-C. Heme oxygenase-1 mediates nicotine- and lipopolysaccharide-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase in human periodontal ligament cells. J Periodont Res 2010; 45: 177–183. © 2010 John Wiley & Sons A/S</I></P><P>Background and Objective: </P><P>Although heme oxygenase-1 (HO-1) plays a key role in inflammation, its anti-inflammatory effects and mechanism of action in periodontitis are still unknown. This study aimed to identify the effects of HO-1 on the proinflammatory mediators activated by nicotine and lipopolysaccharide (LPS) stimulation in human periodontal ligament (PDL) cells.</P><P>Material and Methods: </P><P>The production of nitric oxide (NO) and prostaglandin E<SUB>2</SUB> (PGE<SUB>2</SUB>) was evaluated using Griess reagent and an enzyme immunoassay, respectively. The expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and HO-1 proteins was evaluated by Western blot analysis.</P><P>Results: </P><P>Lipopolysaccharide and nicotine synergistically induced the production of NO and PGE<SUB>2</SUB> and increased the protein expression of iNOS, COX-2 and HO-1. Treatment with an HO-1 inhibitor and HO-1 small interfering RNAs blocked the LPS- and nicotine-stimulated NO and PGE<SUB>2</SUB> release as well as the expression of iNOS and COX-2.</P><P>Conclusion: </P><P>Our data suggest that the nicotine- and LPS-induced inflammatory effects on PDL cells may act through a novel mechanism involving the action of HO-1. Thus, HO-1 may provide a potential therapeutic target for the treatment of periodontal disease associated with smoking and dental plaque.</P>

성장단계별 농후사료 (濃厚飼料) 급여수준이 한우 육성빈우의 (育成牝牛) 체중변화 및 번식능력에 미치는 영향

강수원(S . W . Kang),장선식(S . S . Jang),임석기(S . K . Im),정창화(C . H . Chung),신기준(K . J . Shin) 한국영양사료학회 1996 韓國營養飼料學會誌 Vol.20 No.2

1987년 한국에서 발생한 렙토스피라병의 혈청역학적 조사

이증훈,박영수,이우곤,김석용,정선식,우준희,박성광,박경희,송영욱,김선영,기정일,최두혁,강성귀,김주완,최강원,김우열,최명식,최인학,장우현,윤성열 대한감염학회 1988 감염 Vol.20 No.3

Human leptospirosis was an unfamiliar disease in Korea until 1984 that outbreak of leptospirosis occurred among farmers and soldiers after field works for harvesting rice. During that time, Lee and Jo confirmed the first Korean cases of leptospirosis by serological test, isolation of causative agent and autopy findings. Afterward several outbreaks occurred also during autumn especially after flood in every years and some characterisitcs of leptospirosis in Korea such as clinical manifestations, serotypes and seroepidemiological features has been revealed by many investigators. Because of the major mode of transmission between rodents and human is by direct contact with leptospiral urine of rodents or contaminated soil by the urine, leptospirosis in Korea has been primarily a disease of person in occupations heavily exposed to contaminated soil or infected urine such as farmer, army and etc. Therefore it seems that leptospirosis is one of the main communicable diseases to be controlled urgently in Korea, for an agricultural people account for almost half of total Korean people. For clarifying the seroepidemiological patterns of human leptospirosis in Korea by sex, month region and main reacting serovars of L. interrogans among acute febrile disease occurred in 1987, 1,773 patient's sers with acute febrile episodes were tested by microagglutination test using 19 representative strains of leptospiral serogroup as antigen. All of those sera were collected from 10 collaborative clinics located in Kyunggi, Kangwon, Chungbuk, Chungnam, Chonbuk, Chonnam province and Seoul. The results wee summerized as follows. 1) Among 1,773 sera of patients with acute febrile episodes, 219 (12.4%) were seropositive to L. interrogans, 487(27.5%) to R. tsutsugamushi, 241(13.6%) to R.typhi and 160(90.0%) to Hantaan virus. 2) Among seropositives to L.interrogans, the male outnumbered the female, 65% and 35%. 3) For age distribution, 26.9% of seropositives to L.interrogans were fifties, 19.6% were forties, 9.1% were sixties, 5.9% were thirties and 4.1% were twenties. 4) Eighty three percent of seropositives had occurred between September and October in 1987 with a peak in September. 5) Main leptospiral serovars reactive to patient's sera were Icterohaemorrhagiae(54.3%), Canicola(31.0%), CH-48(13.2%), Tarassovi(0.9%)and Cynopteri(0.5%). 6) For regional distribution, 65.8% of seropositives to L.interrogans were residents from Chonbuk, 12.3% were Chonnam, 7.3% were Chungnam, 5.5% were Kyunggi and 1.4% were Kangwon.

선택적 촉매 산화 반응에 의한 황화수소의 제거 1 . 촉매의 개발

천승우,박대원,우희철,홍성수,정종식 ( S . W . Chun,D . W . Park,H . C . Woo,S . S . Hong,J . S . Chung ) 한국공업화학회 1995 공업화학 Vol.6 No.5

본 연구는 H₂S를 산소와의 직접 산화 반응을 통해 원소 황의 형태로 제거하는 반응에서 고농도의 H₂S를 처리할 수 있는 촉매의 개발에 관한 것이다. 최적의 촉매를 개발하기 위해 각 담체와 금속 산화물에 대한 반응성 실험을 실시하였다. 실험 결과 담체로는 Al₂O₃, TiO₂, ZrO₂ 등이 금속 산화물로서는 Fe₂O₃, V₂O_5, SnO₂, Cr₂O₃ 등이 좋은 활성을 보였다. 반응물 중의 산소의 분압 영향과 반응물에 포함되어질 수 있는 물의 영향에 대해서 관찰한 결과 산소의 분압이 높을수록 전화율은 증가하나 황 선택도는 급격히 감소하는 경향을 보였고, 10vol.%의 물을 반응물에 첨가한 경우 전화율과 황 선택도가 동시에 감소하는 경향을 보였다. In this study, development of catalysts far the direct oxidation of hydrogen sulfide to elemental sulfur, specially for the treatment of high concentrantion of H₂S, was investigated. To find out optimum catalysts, a screenig test for various supports and metal oxides was carried out. Among the supports tested, Al₂O₃, TiO₂ and ZrO₂ showed good catalytic activity. Fe₂O₃, V₂O_5, SnO₂ and Cr₂O₃ have been considered to be active metal oxides. The study on the effects of oxygen partial pressure revealed that the conversion of H₂S increased with increasing the ratio of O₂/H₂S, but the selectivity to sulfur was drasctically decreased. Bath of the conversion of H₂S and the selectivity to sulfur were decreased when 10 vol.% of water was added to the mixture of H₂S and oxygen.

PHF2 histone demethylase acts as a tumor suppressor in association with p53 in cancer

Lee, K-H,Park, J-W,Sung, H-S,Choi, Y-J,Kim, W H,Lee, H S,Chung, H-J,Shin, H-W,Cho, C-H,Kim, T-Y,Li, S-H,Youn, H-D,Kim, S J,Chun, Y-S Macmillan Publishers Limited 2015 Oncogene Vol.34 No.22

Plant homeodomain finger 2 (PHF2) has a role in epigenetic regulation of gene expression by demethylating H3K9-Me2. Several genome-wide studies have demonstrated that the chromosomal region including the PHF2 gene is often deleted in some cancers including colorectal cancer, and this finding encouraged us to investigate the tumor suppressive role of PHF2. As p53 is a critical tumor suppressor in colon cancer, we tested the possibility that PHF2 is an epigenetic regulator of p53. PHF2 was associated with p53, and thereby, promoted p53-driven gene expression in cancer cells under genotoxic stress. PHF2 converted the chromatin that is favorable for transcription by demethylating the repressive H3K9-Me2 mark. In an HCT116 xenograft model, PHF2 was found to be required for the anticancer effects of oxaliplatin and doxorubicin. In PHF2-deficient xenografts, p53 expression was profoundly induced by both drugs, but its downstream product p21 was not, suggesting that p53 cannot be activated in the absence of PHF2. To find clinical evidence about the role of PHF2, we analyzed the expressions of PHF2, p53 and p21 in human colon cancer tissues and adjacent normal tissues from patients. PHF2 was downregulated in cancer tissues and PHF2 correlated with p21 in cancers expressing functional p53. Colon and stomach cancer tissue arrays showed a positive correlation between PHF2 and p21 expressions. Informatics analyses using the Oncomine database also supported our notion that PHF2 is downregulated in colon and stomach cancers. On the basis of these findings, we propose that PHF2 acts as a tumor suppressor in association with p53 in cancer development and ensures p53-mediated cell death in response to chemotherapy.