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Lee MW, Lim S, Jeong W, Kim S, Kim JH, Hwang YS, Sung C. Electron Temperature Measurements Using a Two-Filter Soft X-ray Array in VEST. Sensors (Basel) 2023; 23:8357. [PMID: 37896452 PMCID: PMC10610578 DOI: 10.3390/s23208357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/01/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023]
Abstract
A multichannel soft X-ray (SXR) array has been developed to measure the electron temperature in the Versatile Experiment Spherical Torus (VEST). To estimate electron temperature using the two-filter method applied to SXR intensity, we designed a pinhole camera that has two photodiode arrays with different metallic filters. We also adopted a filter wheel and tested various filter parameters to find the optimal filter set. Through tests, the combination of aluminum and beryllium was found to be the most suitable for the current experimental conditions in VEST. The filtered SXR signals were acquired with a low-noise preamplifier, exhibiting sufficient signal-to-noise ratios for electron temperature estimation based on the intensity ratio of two signals obtained with different filters. The estimated electron temperature from the developed two-filter SXR array showed reasonably matched levels and consistent trends with Thomson scattering measurements. Error contribution from impurity line emission is also discussed.
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Affiliation(s)
- M. W. Lee
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea;
| | - S. Lim
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea; (S.L.); (W.J.); (S.K.); (J.H.K.); (Y.S.H.)
| | - W. Jeong
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea; (S.L.); (W.J.); (S.K.); (J.H.K.); (Y.S.H.)
| | - S. Kim
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea; (S.L.); (W.J.); (S.K.); (J.H.K.); (Y.S.H.)
| | - J. H. Kim
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea; (S.L.); (W.J.); (S.K.); (J.H.K.); (Y.S.H.)
| | - Y. S. Hwang
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea; (S.L.); (W.J.); (S.K.); (J.H.K.); (Y.S.H.)
| | - C. Sung
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea;
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Arora S, Wilder S, Butaney M, Rogers C, Jeong W. Outcomes of precision prostatectomy procedure for localized prostate cancer, and step-by-step technique of single port transvesical precision prostatectomy. Eur Urol 2023. [DOI: 10.1016/s0302-2838(23)01372-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Park J, Wu H, Kim J, Lee J, Ahn S, Chung E, Eom K, Jeong W, Kwon T, Kim S, Wee C. PD-0823 Adjuvant Radiotherapy for Node-negative Parotid Gland Cancer Patients Undergoing Curative Resection. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)02964-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rhee C, Kang Y, Han B, Kim YW, Her M, Jeong W, Kim S. Virucidal efficacy of seven active substances in commercial disinfectants used against H9N2 low pathogenic avian influenza virus. J APPL POULTRY RES 2021. [DOI: 10.1016/j.japr.2021.100198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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KIM D, Wu H, Kim J, Ahn S, Chung E, Eom K, Jung Y, Jeong W, Kwon T, Kim S, Wee C. PO-0986 Radiotherapy versus Surgery in Early Stage HPV-positive Oropharyngeal Cancer. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07437-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Sood A, Keeley J, Palma-Zamora I, Chien M, Dalela D, Arora S, Jamil M, Kovacevic N, Corsi N, Jeong W, Rogers C, Trinh QD, Peabody J, Menon M, Abdollah F. Anti-androgen therapy overcomes the time-delay in initiation of salvage radiation therapy and rescues the oncological outcomes in men with recurrent prostate cancer after radical prostatectomy: A post-hoc analysis of the RTOG 9601 trial data. Eur Urol 2021. [DOI: 10.1016/s0302-2838(21)01553-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sood A, Keeley J, Dalela D, Arora S, Palma-Zamora I, Jamil M, Kovacevic N, Jeong W, Trinh QD, Rogers C, Peabody J, Menon M, Abdollah F. Does concomitant anti-androgen therapy improve outcomes in patients with recurrent prostate cancer undergoing early salvage radiation therapy. EUR UROL SUPPL 2020. [DOI: 10.1016/s2666-1683(20)33294-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Kovacevic N, Sood A, Keeley J, Dalela D, Arora S, Palma-Zamora I, Jamil M, Jeong W, Trinh QD, Rogers C, Peabody J, Menon M, Abdollah F. Identifying patients that may benefit from addition of bicalutamide to salvage radiation therapy in the setting of biochemical failure after radical prostatectomy. EUR UROL SUPPL 2020. [DOI: 10.1016/s2666-1683(20)33295-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Kim N, Jeong W, Heo C, Park K, Lee J, Ryu M, Kim J, Pak K, Kim Y, Shin Y. Skin-adhesive extracranial photobiomodulation improved memory and depression in mild cognitive impairment: A randomized, controlled, single-blind pilot study. J Neurol Sci 2019. [DOI: 10.1016/j.jns.2019.10.796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abdollah F, Jeong W, Dalela D, Palma-Zamora I, Sood A, Menon M. Menon-precision prostatectomy (MPP): An idea, development, exploration, assessment, long-term follow-up (IDEAL) stage 1 study. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/s1569-9056(19)30460-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Jeong W, Keighley C, Wolfe R, Lee W, Slavin M, Kong D, Chen SA. The epidemiology and clinical manifestations of mucormycosis: a systematic review and meta-analysis of case reports. Clin Microbiol Infect 2019; 25:26-34. [DOI: 10.1016/j.cmi.2018.07.011] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 12/20/2022]
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Kim J, Jeong I, Choi H, Jeong W, Jeong S, Son T, Ku N, Choi J, Kim J. Comparison of open, robotic and laparoscopic gastrectomy with surgical site infection in patients with advanced gastric cancer: a retrospective cohort study. Int J Infect Dis 2018. [DOI: 10.1016/j.ijid.2018.04.4084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Jeong W, Bae H, Lim W, Bazer FW, Song G. Adiponectin: A prosurvival and proproliferation signal that increases bovine mammary epithelial cell numbers and protects them from endoplasmic reticulum stress responses. J Anim Sci 2018; 95:5278-5289. [PMID: 29293771 DOI: 10.2527/jas2017.1885] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cell-cell interactions between epithelial and stromal cells are predominant in the mammary gland, and various stromal cell-derived factors can elicit mitogenic responses in adjacent epithelial cells. Adiponectin is a hormone secreted mainly by adipocytes that mediates stromal-epithelial interactions in a number of tissues. Adiponectin receptors are expressed by bovine mammary epithelial cells, but the regulatory effects of adiponectin on the development and function of the mammary gland remain unclear. We therefore sought to investigate the effects of adiponectin on bovine mammary epithelial (MAC-T) cells and the regulatory mechanisms that underlie these adiponectin-induced actions. Our results revealed an increase in MAC-T cell proliferation and cell cycle progression in response to adiponectin. The expression of nuclear proliferating cell nuclear antigen (PCNA) and cyclin D1 was induced in MAC-T cells, and intracellular signaling molecules such as serine/threonine protein kinase (AKT), 70 kDa ribosomal S6 kinase (P70S6K), ribosomal protein S6 (S6), extracellular signal-regulated kinases 1 and 2 (ERK1/2), 90 kDa ribosomal S6 kinase (P90S6K), and cyclin D1 were activated in a dose-dependent manner. The abundance of adiponectin-induced signaling proteins was suppressed following inhibition of AKT or ERK1/2 mitogen-activated protein kinase (MAPK) signaling. In addition, inhibition of AKT or ERK1/2 signaling significantly reduced adiponectin-stimulated MAC-T cell proliferation. Furthermore, adiponectin reduced tunicamycin-induced expression and activation of endoplasmic reticulum stress-related proteins in MAC-T cells and attenuated the repressive effect of tunicamycin on proliferation of MAC-T cells. Collectively, these results suggest that adiponectin-mediated signaling may affect the development and function of the mammary gland in dairy cows by increasing mammary epithelial cell numbers. These findings may result in important implications for improving our fundamental understanding of lactation physiology in livestock species.
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Jeong W, Bae H, Lim W, Bazer FW, Lee H, Song G. The functional effects and mechanisms by which fibroblast growth factor 2 (FGF2) controls bovine mammary epithelial cells: Implications for the development and functionality of the bovine mammary gland. J Anim Sci 2018; 95:5365-5377. [PMID: 29293786 DOI: 10.2527/jas2017.1877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Fibroblast growth factor (FGF) signaling plays essential roles in tissue development and homeostasis. Accumulating evidence reveals that fibroblast growth factor 2 (FGF2) regulates ductal elongation, which requires cell proliferation and epithelial expansion in the mammary gland. However, the function and mechanisms by which FGF2 controls functionality of epithelial cells is less well defined. Here, we demonstrate the functional effects of FGF2 on bovine mammary epithelial (MAC-T) cells and the intracellular signaling mechanisms for these FGF2-induced actions. The current results show that treatment of MAC-T cells with a recombinant FGF2 induced cell proliferation and cell-cycle progression with increased expression of proliferating cell nuclear antigen and cyclin D1. Moreover, FGF2 increased phosphorylation of serine/threonine protein kinase (protein kinase B [AKT]), extracellular signal-regulated kinases 1 and 2 (ERK1/2), Jun N-terminal kinase (JNK), 70 kDa ribosomal S6 kinase (P70S6K), 90 kDa ribosomal S6 kinase (P90S6K), ribosomal protein S6 (S6), and cyclin D1 proteins. These FGF2-induced activations of signaling pathway proteins were inhibited by blocking AKT, ERK1/2, or JNK phosphorylation. The effect of FGF2 to stimulate MAC-T cell proliferation was mediated by activation of FGF receptors (FGFR) and AKT, ERK1/2, and JNK mitogen-activated protein kinase pathways in response to FGF2 stimulation. Furthermore, expression and activation of endoplasmic reticulum (ER) stress-related factors and ER stress-induced MAC-T cell death was reduced by FGF2. Together, these results suggest that the FGF2-FGFR-intracellular signaling cascades may contribute to maintaining and/or increasing numbers of mammary epithelial cells by inducing proliferation of mammary epithelial cells and by protecting cells from ER stress responses. Therefore, this study provides evidence that FGF2 signaling is a positive factor for mammary gland remodeling and for increasing persistency of milk production.
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Jeong W, Bae H, Lim W, Song G. Dicer1, AGO3, and AGO4 microRNA machinery genes are differentially expressed in developing female reproductive organs and overexpressed in cancerous ovaries of chickens. J Anim Sci 2018; 95:4857-4868. [PMID: 29293730 DOI: 10.2527/jas2017.1846] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
MicroRNA (miRNA)-mediated gene silencing is a key mechanism regulating numerous biological processes such as development of organs and tumorigenesis. The expression of miRNA machinery genes linked to miRNA biogenesis and processing is finely regulated. Despite accumulating evidence for chicken miRNA in the female reproduction system, precise regulatory mechanisms are largely unknown. Therefore, the objective of this study was to determine changes in expression levels of miRNA machinery genes in developmental stages of the oviduct and ovarian carcinogenesis of laying hens. In the present study, differential expression of miRNA machinery genes during ovarian carcinogenesis was determined using cancerous and normal ovaries collected from normal laying hens and hens with cancer. Our results showed that 3 miRNA machinery genes (, , and ) were differentially expressed as laying hens' reproductive organs developed. These genes were simultaneously upregulated in cancerous ovaries compared with those in normal ovaries. Their transcripts were abundantly localized in glandular epithelial cells of cancerous ovaries. Our results indicate that , , and play critical roles in the development of reproductive organs and ovarian carcinogenesis in laying hens, suggesting that simultaneous overexpression of these genes might serve as a prognostic factor for ovarian cancer.
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Jeong W, Bae H, Lim W, Bazer FW, Song G. Differential expression of neuregulin 1 (NRG1) and candidate miRNA regulating NRG1 transcription in the chicken oviduct in response to hormonal changes. J Anim Sci 2018; 95:3885-3904. [PMID: 28992000 DOI: 10.2527/jas2017.1663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neuregulin 1 (NRG1), a signaling protein that binds to members of the erythroblastoma (ErbB) family, is known to play essential biological roles in mediating cell-cell interactions and orchestrating vital cell functions in the heart and nervous system. NRG1 is closely associated with developmental processes in various organs and expression of several NRG1 isoforms are regulated by estrogen. However, expression and its hormonal regulation during development of the female reproductive tract remain unknown. The reproductive system of chickens undergoes dynamic morphological and functional changes in response to estrogen and the molting process. Therefore, in the current study, we found differential expression of and candidate microRNA regulating chicken transcription in response to estrogen stimulation and/or the molting process. The results revealed that relative expression of mRNA increased in the oviducts of chicks treated with diesthylstilbestrol (DES; a synthetic non-steroidal estrogen). Additionally, abundant NRG1 mRNA expression was primarily in the glandular (GE) and luminal (LE) epithelia of the magnum in the developing chick oviduct in response to exogenous estrogen. Also, expression decreased during regression of the oviduct following induced molting by feeding high levels of zinc in the diet, and then gradually resurged as the oviduct underwent remodeling and recrudescence in laying hens. In addition, the present results revealed changes in relative expression of candidate chicken microRNA (, and ) targeting transcription in chicken oviducts in response to exogenous estrogen. In conclusion, these results provide the first evidence that is a novel estrogen-responsive gene closely correlated with the estrogen-dependent development of the oviduct of chicks and regeneration of the oviduct after molting. Further, regulation of expression involving at least 3 chicken miRNA is likely a prerequisite for those estrogen regulated developmental events.
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Jeong W, Bae H, Lim W, Bazer FW, Song G. Differential expression of neuregulin 1 (NRG1) and candidate miRNA regulating NRG1 transcription in the chicken oviduct in response to hormonal changes1. J Anim Sci 2017. [DOI: 10.2527/jas.2017.1663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Jeong W, Park EJ, Kwon EJ, Cho M, Kim J. FRI0240 SIRT-1 Regulates TGF-β Induced Dermal Fibroblast Migration via Modulation of CYR61 Expression. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.4712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Seong J, Jeong W, Smith N, Towner RA. Hemodynamic effects of long-term morphological changes in the human carotid sinus. J Biomech 2015; 48:956-62. [PMID: 25702250 DOI: 10.1016/j.jbiomech.2015.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/03/2015] [Accepted: 02/05/2015] [Indexed: 11/25/2022]
Abstract
Previous investigations of morphology for human carotid artery bifurcation from infancy to young adulthood found substantial growth of the internal carotid artery with advancing age, and the development of the carotid sinus at the root of the internal carotid artery during teenage years. Although the reasons for the appearance of the carotid sinus are not clearly understood yet, it has been hypothesized that the dilation of the carotid sinus serves to support pressure sensing, and slows the blood flow to reduce pulsatility to protect the brain. In order to understand this interesting evolvement at the carotid bifurcation in the aspects of fluid mechanics, we performed in vitro phase-contrast MR flow experiments using compliant silicone replicas of age-dependent carotid artery bifurcations. The silicone models in childhood, adolescence, and adulthood were fabricated using a rapid prototyping technique, and incorporated with a bench-top flow mock circulation loop using a computer-controlled piston pump. The results of the in vitro flow study showed highly complex flow characteristics at the bifurcation in all age-dependent models. However, the highest magnitude of kinetic energy was found at the internal carotid artery in the child model. The high kinetic energy in the internal carotid artery during childhood might be one of the local hemodynamic forces that initiate morphological long-term development of the carotid sinus in the human carotid bifurcation.
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Affiliation(s)
- Jaehoon Seong
- Department of Mechanical Engineering, California State Polytechnic University, 3801 West Temple Avenue, Pomona, CA 91768, USA.
| | - Woowon Jeong
- Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK, USA
| | - Nataliya Smith
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Rheal A Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
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Jung SC, Choi SH, Cho HR, Lee TH, Kim TY, Jeong W, Rhee K, Jho JY, Kim JH, Han MH. Polymeric embolization coil of bilayered polyvinyl alcohol strand for therapeutic vascular occlusion: a feasibility study in canine experimental vascular models. J Vasc Interv Radiol 2014; 26:117-23. [PMID: 25454653 DOI: 10.1016/j.jvir.2014.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/03/2014] [Accepted: 10/08/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To investigate the feasibility of polyvinyl alcohol (PVA) polymer coil as a new endovascular embolic agent and to gauge the related histologic response in a canine vascular model. MATERIALS AND METHODS PVA polymer coil was fabricated by cross-linking PVA and tantalum particles. Basic properties were then studied in vitro via swelling ratio and bending diameter. Normal renal segmental arteries and wide-necked aneurysms of carotid sidewalls served as canine vascular models. Endovascular PVA coil embolization of normal renal segmental arteries (N = 20) and carotid aneurysms (N = 8) was performed under fluoroscopic guidance in 10 dogs. Degree of occlusion was assessed immediately and at 4 weeks after embolization by conventional and computed tomographic angiography. Histologic features were also graded at acute (day 1, six segmental arteries and four aneurysms) and chronic phases (week 4, 14 segmental arteries and four aneurysms) after embolization to assess inflammation, organization of thrombus, and neointimal proliferation. RESULTS Swelling ratio declined as concentrations of cross-linking agent increased. Mean bending diameters were 2.05 mm (range, 0.86-6.25 mm) in water at 37 °C and 2.29 mm (range, 0.94-6.38 mm) in canine blood samples at 37 °C. Occlusion of normal renal segmental arteries was sustained (complete occlusion at day 1, n = 20; at week 4, n = 14), whereas immediate outcomes in carotid aneurysms (day 1, complete occlusion, n = 5; residual neck only, n = 3) were not sustained (week 4, complete occlusion, n = 1; minor recanalization, n = 1; major recanalization, n = 2). At week 4, chronic inflammatory cells predominated, with progressive organization of thrombus and fibrocellular ingrowth. All aneurysms bore full neointimal linings on the coil mass in the chronic phase. CONCLUSIONS Vascular occlusion by PVA polymer coil proved superior in normal renal segmental arteries and feasible in surgically constructed carotid aneurysms (with packing densities ≥ 30%), constituting acceptable radiologic feasibility and histologic response.
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Affiliation(s)
- Seung Chai Jung
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; Department of Radiology, Asan Medical Center, Seoul, Korea
| | - Seung Hong Choi
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea
| | - Hye Rim Cho
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea
| | - Tae Hoon Lee
- School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea
| | - Tae Yang Kim
- School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea
| | - Woowon Jeong
- Department of Mechanical Engineering, Myongji University, Seoul, Korea
| | - Kyehan Rhee
- Department of Mechanical Engineering, Myongji University, Seoul, Korea
| | - Jae Young Jho
- School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea
| | - Jae Hyoung Kim
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea
| | - Moon Hee Han
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea.
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Jeong W, Han M, Rhee K. The hemodynamic alterations induced by the vascular angular deformation in stent-assisted coiling of bifurcation aneurysms. Comput Biol Med 2014; 53:1-8. [DOI: 10.1016/j.compbiomed.2014.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/07/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
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Oh JS, Kwon YS, Lee KH, Jeong W, Chung SK, Rhee K. Drug perfusion enhancement in tissue model by steady streaming induced by oscillating microbubbles. Comput Biol Med 2014; 44:37-43. [DOI: 10.1016/j.compbiomed.2013.10.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/11/2013] [Accepted: 10/19/2013] [Indexed: 12/20/2022]
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Song J, Jang J, Cho Y, Jeong W, Park D, Jang A, Kwon S. WITHDRAWN: Effect of ventilation type on the transport of coughed particles in a hospital room using computational fluid dynamics. J IND ENG CHEM 2013. [DOI: 10.1016/j.jiec.2013.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Jeong W, Han MH, Rhee K. Effects of framing coil shape, orientation, and thickness on intra-aneurysmal flow. Med Biol Eng Comput 2013; 51:981-90. [DOI: 10.1007/s11517-013-1073-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/29/2013] [Indexed: 11/30/2022]
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Ganjeh Y, Song B, Pagadala K, Kim K, Sadat S, Jeong W, Kurabayashi K, Meyhofer E, Reddy P. A platform to parallelize planar surfaces and control their spatial separation with nanometer resolution. Rev Sci Instrum 2012; 83:105101. [PMID: 23126798 DOI: 10.1063/1.4754643] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Parallelizing planar surfaces and manipulating them into close proximity with spatial separation of nanoscale dimensions is critical for probing phenomena such as near-field radiative heat transport and Casimir forces. Here, we report on a novel platform, with an integrated reflected light microscope, that is capable of parallelizing two planar surfaces such that the angular deviation is <6 μrad, while simultaneously allowing control of the gap from 15 μm down to contact with ∼0.15 nm resolution. The capabilities of this platform were verified by using two custom-fabricated micro-devices with planar surfaces, 60 × 60 μm(2) each, whose flatness and surface roughness were experimentally quantified. We first parallelized the two micro-devices by using the developed platform in conjunction with a simple optical approach that relies on the shallow depth of field (∼2 μm) of a long working distance microscope objective. Subsequently, we experimentally tested the parallelism achieved via the optical alignment procedure by taking advantage of electrodes integrated into the micro-devices. Our measurements unambiguously show that the simple depth-of-field based optical approach enables parallelization such that the angular deviation between the two surfaces is within ∼500 μrad. This ensures that the separation between any two corresponding points on the parallel surfaces deviate by ∼30 nm or less from the expected value. Further, we show that improved parallelization can be achieved using the integrated micro-electrodes which enable surface roughness limited parallelization with deviations of ∼5 nm from parallelism.
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Affiliation(s)
- Y Ganjeh
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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Lee KW, Lillehoj HS, Park MS, Jang SI, Ritter GD, Hong YH, Jeong W, Jeoung HY, An DJ, Lillehoj EP. Clostridium perfringens alpha-toxin and NetB toxin antibodies and their possible role in protection against necrotic enteritis and gangrenous dermatitis in broiler chickens. Avian Dis 2012; 56:230-3. [PMID: 22545552 DOI: 10.1637/9847-070711-resnote.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Necrotic enteritis (NE) and gangrenous dermatitis (GD) are important infectious diseases of poultry. Although NE and GD share a common pathogen, Clostridium perfringens, they differ in other important aspects such as clinical signs, pathologic symptoms, and age of onset. The primary virulence factors of C perfringens are its four major toxins (alpha, beta, epsilon, iota) and the newly described NE B-like (NetB) toxin. While neutralizing antibodies against some C perfingens toxins are associated with protection against infection in mammals, the serologic responses of NE- and GD-afflicted birds to these toxins have not been evaluated. Therefore, we measured serum antibody levels to C perfringens alpha-toxin and NetB toxin in commercial birds from field outbreaks of NE and GD using recombinant toxin-based enzyme-linked immunosorbent assay (ELISA). Initially, we used this ELISA system to detect antibody titers against C perfringens alpha-toxin and NetB toxin that were increased in birds experimentally coinfected with Eimeria maxima and C perfringens compared with uninfected controls. Next, we applied this ELISA to field serum samples from flock-mated birds with or without clinical signs of NE or GD. The results showed that the levels of antibodies against both toxins were significantly higher in apparently healthy chickens compared to birds with clinical signs of NE or GD, suggesting that these antitoxin antibodies may play a role in protection against NE and GD.
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Affiliation(s)
- K W Lee
- Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, USDA, Beltsville, MD 20705, USA
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Rogers C, Sukumar S, Jeong W, Petros F, Sammon J, Trinh Q, Menon M. MP-14.12 Intraoperative Finding of Gross Lymph Node Metastasis During Robotic Radical Prostatectomy. Urology 2011. [DOI: 10.1016/j.urology.2011.07.334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Jeong W, Kang C. The histidine-805 in motif-C of the phage SP6 RNA polymerase is essential for its activity as revealed by random mutagenesis. IUBMB Life 2011; 42:711-6. [PMID: 19856287 DOI: 10.1080/15216549700203131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In order to identify functional residues of the bacteriophage SP6 RNA polymerase, its C-terminal one-twelfth region was randomly mutagenized using polymerase chain reactions of its gene under the conditions for reduced fidelity of Taq DNA polymerase. Using a two-vector system that permits phenotypic isolation of mutants with reduced in vivo transcription activity, 3 single and 1 multiple mutants were isolated. A single substitution of Gln for His805 resulted in complete inactivation of the enzyme. A multiple mutant carrying substitutions at 808, 820, 835, 843 and 848 also abolished the activity. However, changes of Pro856-->Ser and Asp862-->Glu individually reduced the activity only slightly. It is noteworthy that His805 is one of the two motif-C residues that are absolutely conserved among all the DNA polymerases and monomeric RNA polymerases.
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Affiliation(s)
- W Jeong
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Taejon, Korea
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Lee K, Lillehoj H, Jeong W, Jeoung H, An D. Avian necrotic enteritis: Experimental models, host immunity, pathogenesis, risk factors, and vaccine development. Poult Sci 2011; 90:1381-90. [DOI: 10.3382/ps.2010-01319] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Lee H, Lee R, Suh T, Jeong W, Xing L. High Quality and Low Dose Cone-beam CT Imaging with Anisotropic Regularized FDK Reconstruction Algorithm. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kwon YK, Kim A, Kang MS, Her M, Jung BY, Lee KM, Jeong W, An BK, Kwon JH. Prevalence and characterization ofSalmonella Gallinarum in the chicken in Korea during 2000 to 2008. Poult Sci 2010; 89:236-42. [DOI: 10.3382/ps.2009-00420] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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32
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Cerny J, Moltz DM, Lee DW, Peräjärvi K, Barquest BR, Grossman LE, Jeong W, Jewett CC. Reinvestigation of the direct two-proton decay of the long-lived isomer 94Ag(m) [0.4 s, 6.7 MeV, (21+)]. Phys Rev Lett 2009; 103:152502. [PMID: 19905629 DOI: 10.1103/physrevlett.103.152502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Indexed: 05/28/2023]
Abstract
An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + (nat)Ni reaction at 197 MeV to a low-background area; 24 gas DeltaE-(Si)E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)%. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)%.
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Affiliation(s)
- J Cerny
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Mohan V, Chawla T, Alzwahereh K, Jeong W, Kita KY, Chua VS, Kalra A, Rana GS, Chawla SP. Updated results of Phase II study of trabectedin (ET-743) in pretreated patients with advanced/metastatic soft tissue sarcoma from a single institute. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.21506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Rhee SG, Jeong W, Chang TS, Woo HA. Sulfiredoxin, the cysteine sulfinic acid reductase specific to 2-Cys peroxiredoxin: its discovery, mechanism of action, and biological significance. Kidney Int 2007:S3-8. [PMID: 17653208 DOI: 10.1038/sj.ki.5002380] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Peroxiredoxin (Prx) is a family of bifunctional proteins that exhibit peroxidase and chaperone activities. Prx proteins contain a conserved Cys residue that undergoes a redox change between thiol and disulfide states. 2-Cys Prx enzymes, a subgroup of Prx family, are intrinsically susceptible to reversible hyperoxidation to cysteine sulfinic acid during catalysis. Cysteine hyperoxidation of Prx was shown to result in loss of peroxidase activity and a concomitant gain of chaperone activity. Reduction of sulfinic Prx enzymes, the first known biological example of such a reaction, is catalyzed by sulfiredoxin (Srx) in the presence of ATP. Srx appears to exist solely to support the reversible sulfinic modification of 2-Cys Prx enzymes. Srx specifically binds to 2-Cys Prx enzymes by recognizing several critical surface-exposed residues of the Prxs, and transfer the gamma-phosphate of ATP to their sulfinic moiety, using its conserved cysteine as the phosphate carrier. The resulting sulfinic phosphoryl ester is reduced to cysteine after oxidation of four thiol equivalents.
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Affiliation(s)
- S G Rhee
- Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul, Korea.
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Kim G, Jeong W, Choi S, Khim J. Sand capping for controlling phosphorus release from lake sediments. Environ Technol 2007; 28:381-9. [PMID: 17500313 DOI: 10.1080/09593332808618801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In this research, the use of the sand capping technique for controlling phosphorus release from lake sediment was evaluated experimentally. Multiple acrylic columns were prepared to measure the dissolved oxygen, oxidation reduction potential, total phosphorus, and phosphate concentrations of the overlying water on the capping layer with thicknesses of 0, 40, and 80 mm. Sand capping effectively slowed down the reactions that depleted the dissolved oxygen, which as a result, controlled the total phosphorus release from the sediment. Oxidation reduction potential of overlying water was estimated by measuring dissolved oxygen in situ or vice versa by an empirical model proposed in this research. Sediment disturbance should be considered during field construction of the cap system. The experimental results showed that phosphorus existed in a more stable form with capping than without capping.
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Affiliation(s)
- G Kim
- Department of Civil and Environmental Engineering, Hannam University, Ojungdong, Daejon 306-791, Republic of Korea
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Rhee C, Jeong W, Kim J, Kim S, Won T, Kim Y, Lee C, Cho S, Min Y. Criterion for Eosinophilic Nasal Polyp: A Clinicopathologic Correlation. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.11.267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
4142 Background: Based on the single-agent efficacies observed in phase II trials (Cancer 2004;101:578–586 and Cancer 2005;103:749–755), a pilot trial with a combination of oral capecitabine and thalidomide has been conducted in patients with unresectable, recurrent or metastatic hepatocellular carcinoma (HCC) to evaluate its efficacy and toxicity. Methods: The regimen consisted of capecitabine at a dose of 750 mg/m2 po bid for 14 days every 3 weeks and thalidomide at 400 mg po bed time. Eligibility criteria included histological diagnosis of HCC, measurable disease, no prior systemic therapy, age ≥18 years, ECOG performance score (PS) of ≤2, adequate hematological, hepatic and gastrointestinal functions, no metabolic encephalopathy, and informed consent. Results: A total of 29 patients have been accrued. Two patients had never received the protocol therapy due to rapid deterioration of clinical condition after registration. Twenty-seven have been treated according to the protocol. Patient characteristics included median (range) age -60 (48–77) years; male -24; median ECOG PS -1; cirrhosis -22; hepatitis C antibody -19; hepatitis B surface antigen -4; hemochromatosis -1; extrahepatic metastasis -5. Eight patients were not evaluable for response since they received less than 2 cycles of protocol therapy. Five patients had grade 3 but asymptomatic, transient hyperbilirubinemia. Three patients had grade 1 hand-foot syndrome. Three patients had excessive somnolence which required a reduction of thalidomide dose to 200 mg. Among 19 patients evaluable for response (received ≥ 3 cycles of capecitabine), 1 patient had complete response for 5 months (Time to progression [TTP] -7 months), 4 had partial responses (TTP -2.5, 5.0, 6.0, & 7.0 months) and 4 had stable diseases for ≥ 3 months. Conclusions: This result suggests clinical efficacy of the combination of oral capecitabine and thalidomide, at given doses and schedules, with acceptable safety profile in patients with HCC (Supported by a grant from Celgene Corporation). No significant financial relationships to disclose.
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Affiliation(s)
- W. Jeong
- New York Medical College, Valhalla, NY
| | | | - D. Cer
- New York Medical College, Valhalla, NY
| | - V. Sekhri
- New York Medical College, Valhalla, NY
| | | | - D. Wolf
- New York Medical College, Valhalla, NY
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Jeong KS, Lee J, Jeong W, Noh DH, Do SH, Kim YK. Measurement of estrogen effect on bone turnover by 2H2O labeling. Calcif Tissue Int 2005; 76:365-70. [PMID: 15742235 DOI: 10.1007/s00223-004-1103-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Accepted: 10/06/2004] [Indexed: 10/25/2022]
Abstract
Estrogen loss has been known to increase bone turnover through accelerated bone resorption coupled by increased bone formation. In the present study, we measured estrogen effect on bone turnover by incorporation of 2H from 2H2O into amino acids. At 6 weeks of age, rats were either sham-operated (sham) or ovariectomized (ovx). Two weeks after surgery, 17beta-estradiol (est) was implanted subcutaneously to ovx rats. At 9 weeks of age, 2H2O labeling started by administration of 4% 2H2O to rats for 4 or 7 weeks in drinking water after a single intraperitonial bolus injection with 99.9% 2H2O. Body 2H2O enrichments were stable at approximately 3.0% over labeling period. Fractional replacements (f) of the midshaft femur were higher in the sham group (40.36 +/- 4.89% vs 42.47 +/- 11.22%) than the ovx (28.57 +/- 9.67% vs 37.47 +/- 8.34%) and est (26.57 +/- 4.00% vs 30.35 +/- 5.34%) groups 4 and 7 weeks after labeling, respectively. Ovariectomy-induced bone loss was observed in the trabecular bone along with a significantly increased number of osteoclasts, all of which were normalized after estradiol treatment. Taken together, our results indicate that estrogen deficiency significantly reduces the proportion of newly synthesized bone matrix as well as the total amount of bone matrix. The reduced portion of new matrix in ovx rats, presumably caused by activated osteoclastic degradation, was compensated rapidly with time. In addition, estradiol treatment protected the bone matrix by decreasing bone turnover rate.
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Affiliation(s)
- K S Jeong
- Department of Veterinary Pathology, College of Veterinary Medicine, Kyungpook National University, South Korea
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Affiliation(s)
- S G Rhee
- Laboratory of Cell Signaling, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-8015, USA.
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Abstract
A new type of peroxidase ("thiol peroxidase"; TPx) having cysteine as the primary site of catalysis has been discovered from prokaryotes to eukaryotes. In addition to two yeast TPx isoforms (TSA I and TSA II/AHPC1) previously described, three additional TPx homologues were identified by analysis of the open reading frame data base for Saccharomyces cerevisiae. Three novel isoforms showed a distinct thiol peroxidase activity supported by thioredoxin, and appeared to be distinctively localized in cytoplasm, mitochondria, and nucleus. Each isoform was named after its subcellular localization such as cytoplasmic TPx I (cTPx I or TSA I), cTPx II, cTPx III (TSA II/AHPC1), mitochondrial TPx (mTPx), and nuclear TPx (nTPx). Their transcriptional activities suggest that cTPx I and cTPx III are the most predominant isoforms among the five type isoforms. Transcriptional activities of TPx isoenzymes during yeast life span were quite different from each other. Unlike other TPx null mutants, cTPx I null mutant was hypersensitive to various oxidants except for 4-nitroquinoline N-oxide. The null mutant was more resistant toward 4-nitroquinoline N-oxide and acidic culture than its wild type. The severe growth retardation of cTPx II mutant resulted in accumulation of G(1)-phased cells. Based on kinetic properties of five isoforms, their subcellular localizations, and distinct physiology of each null mutant, we discussed the physiological functions of five types of TPx isoenzymes in yeast throughout the full growth cycle.
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Affiliation(s)
- S G Park
- National Creative Research Initiatives Center for Antioxidant Proteins, Department of Biochemistry, Paichai University, Taejon 302-735, Korea
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Jeong W, Cha MK, Kim IH. Thioredoxin-dependent hydroperoxide peroxidase activity of bacterioferritin comigratory protein (BCP) as a new member of the thiol-specific antioxidant protein (TSA)/Alkyl hydroperoxide peroxidase C (AhpC) family. J Biol Chem 2000; 275:2924-30. [PMID: 10644761 DOI: 10.1074/jbc.275.4.2924] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Escherichia coli bacterioferritin comigratory protein (BCP), a putative bacterial member of the TSA/AhpC family, was characterized as a thiol peroxidase. BCP showed a thioredoxin-dependent thiol peroxidase activity. BCP preferentially reduced linoleic acid hydroperoxide rather than H(2)O(2) and t-butyl hydroperoxide with the use of thioredoxin as an in vivo immediate electron donor. The value of V(max)/K(m) of BCP for linoleic acid hydroperoxide was calculated to be 5-fold higher than that for H(2)O(2), implying that BCP has a selective capability to reduce linoleic acid hydroperoxide. Replacement of Cys-45 with serine resulted in the complete loss of thiol peroxidase activity, suggesting that BCP is a new bacterial member of TSA/AhpC family having a conserved cysteine as the primary site of catalysis. BCP exists as a monomer, and its functional Cys-45 appeared to exist as cysteine sulfenic acid. The expression level of BCP gradually elevated during exponential growth until mid-log phase growth, beyond which the expression level was decreased. BCP was induced 3-fold by the oxidative stress given by changing the growth conditions from the anaerobic to aerobic culture. Bcp null mutant grew more slowly than its wild type in aerobic culture and showed the hypersensitivity toward various oxidants such as H(2)O(2), t-butyl hydroperoxide, and linoleic acid hydroperoxide. The peroxide hypersensitivity of the null mutant could be complemented by the expression of bcp gene. Taken together, these data suggest that BCP is a new member of thioredoxin-dependent TSA/AhpC family, acting as a general hydroperoxide peroxidase.
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Affiliation(s)
- W Jeong
- National Creative Research Center for Antioxidant Proteins, Department of Biochemistry, PaiChai University, Taejon 302-735, Korea
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Kim YJ, Cha SS, Kim JS, Shin NK, Jeong W, Shin HC, Oh BH, Hahn JH. Determination of the limited trypsinolysis pathways of tumor necrosis factor-alpha and its mutant by electrospray ionization mass spectrometry. Anal Biochem 1999; 267:279-86. [PMID: 10036131 DOI: 10.1006/abio.1998.2999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is employed to directly analyze the limited trypsinolysis products of wild-type tumor necrosis factor-alpha (wtTNF-alpha) and its mutant, M3S. To determine the charge numbers of peaks of relatively small peptides in the ESI mass spectrum of a digest, a series of sodium-adduct ion peaks of each peptide are generated by adding a small quantity of NaCl to the digest before taking the spectrum. From the monitoring of the composition of proteolytic mixture as the incubation time is lengthened, it has been learned that the proteolysis of wtTNF-alpha by trypsin occurs sequentially: Arg2, Arg6, Arg32, Arg31, and Arg44, and that M3S is strongly resistant to the proteolysis. Since the cleavage sequence of wtTNF-alpha and the mutation-induced resistance of M3S are consistent with the structural features of the proteins, we can suggest a mutant more resistant to proteolysis than M3S, which has an additional point mutation, Ala35Leu or Ala35Ile.
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Affiliation(s)
- Y J Kim
- Center for Biofunctional Molecules and Department of Chemistry, Pohang University of Science and Technology, San 31 Hyoja Dong, Pohang, 790-784, South Korea
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Kim YR, Hahn JS, Hong H, Jeong W, Song NW, Shin HC, Kim D. Dynamic equilibrium unfolding pathway of human tumor necrosis factor-alpha induced by guanidine hydrochloride. Biochim Biophys Acta 1999; 1429:486-95. [PMID: 9989234 DOI: 10.1016/s0167-4838(98)00263-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The dynamic equilibrium unfolding pathway of human tumor necrosis factor-alpha (TNF-alpha) during denaturation at different guanidine hydrochloride (GdnHCl) concentrations (0-4.2 M) was investigated by steady-state fluorescence spectroscopy, potassium iodide (KI) fluorescence quenching, far-UV circular dichroism (CD), picosecond time-resolved fluorescence lifetime, and anisotropy decay measurements. We utilized the intrinsic fluorescence of Trp-28 and Trp-114 to characterize the conformational changes involved in the equilibrium unfolding pathway. The detailed unfolding pathway under equilibrium conditions was discussed with respect to motional dynamics and partially folded structures. At 0-0.9 M [GdnHCl], the rotational correlation times of 22-25 ns were obtained from fluorescence anisotropy decay measurements and assigned to those of trimeric states by hydrodynamic calculation. In this range, the solvent accessibility of Trp residues increased with increasing [GdnHCl], suggesting the slight expansion of the trimeric structure. At 1.2-2.1 M [GdnHCl], the enhanced solvent accessibility and the rotational degree of freedom of Trp residues were observed, implying the loosening of the internal structure. In this [GdnHCl] region, TNF-alpha was thought to be in soluble aggregates having distinct conformational characteristics from a native (N) or fully unfolded state (U). At 4.2 M [GdnHCl], TNF-alpha unfolded to a U-state. From these results, the equilibrium unfolding pathway of TNF-alpha, trimeric and all beta-sheet protein, could not be viewed from the simple two state model (N-->U).
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Affiliation(s)
- Y R Kim
- Department of Chemistry, Yonsei University, Seoul, South Korea.
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Cha SS, Kim JS, Cho HS, Shin NK, Jeong W, Shin HC, Kim YJ, Hahn JH, Oh BH. High resolution crystal structure of a human tumor necrosis factor-alpha mutant with low systemic toxicity. J Biol Chem 1998; 273:2153-60. [PMID: 9442056 DOI: 10.1074/jbc.273.4.2153] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A human tumor necrosis factor-alpha (TNF-alpha) mutant (M3S) with low systemic toxicity in vivo was designed, and its structures in two different crystal packings were determined crystallographically at 1.8 and 2.15-A resolution, respectively, to explain altered biological activities of the mutant. M3S contains four changes: a hydrophilic substitution of L29S, two hydrophobic substitutions of S52I and Y56F, and a deletion of the N-terminal seven amino acids that is disordered in the structure of wild-type TNF-alpha. Compared with wild-type TNF-alpha, it exhibits 11- and 71-fold lower binding affinities for the human TNF-R55 and TNF-R75 receptors, respectively, and in vitro cytotoxic effect and in vivo systemic toxicity of M3S are 20 and 10 times lower, respectively. However, in a transplanted solid tumor mouse model, M3S suppresses tumor growth more efficiently than wild-type TNF-alpha. M3S is highly resistant to proteolysis by trypsin, and it exhibits increased thermal stability and a prolonged half-life in vivo. The L29S mutation causes substantial restructuring of the loop containing residues 29-36 into a rigid segment as a consequence of induced formation of intra- and intersubunit interactions, explaining the altered receptor binding affinity and thermal stability. A mass spectrometric analysis identified major proteolytic cleavage sites located on this loop, and thus the increased resistance of M3S to the proteolysis is consistent with the increased rigidity of the loop. The S52I and Y56F mutations do not induce a noticeable conformational change. The side chain of Phe56 projects into a hydrophobic cavity, while Ile52 is exposed to the bulk solvent. Ile52 should be involved in hydrophobic interactions with the receptors, since a mutant containing the same mutations as in M3S except for the L29S mutation exhibits an increased receptor binding affinity. The low systemic toxicity of M3S appears to be the effect of the reduced and selective binding affinities for the TNF receptors, and the superior tumor-suppression of M3S appears to be the effect of its weak but longer antitumoral activity in vivo compared with wild-type TNF-alpha. It is also expected that the 1.8-A resolution structure will serve as an accurate model for explaining the structure-function relationship of wild-type TNF-alpha and many TNF-alpha mutants reported previously and for the design of new TNF-alpha mutants.
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Affiliation(s)
- S S Cha
- Department of Life Science, Pohang University of Science and Technology, Hyoja-dong, Kyungbuk, South Korea
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Abstract
The effects of single base pair substitutions at the initiation sites of lacUV5 promoter on the transcription start site selection by E. coli RNA polymerase were systematically studied. Transcription start sites were mapped by sizing the cytosine-specifically terminated transcripts produced in vitro by using a chain terminator 3'-deoxycytidine 5'-triphosphate (3'-dCTP) in transcription reactions. Transcription of a prototype lacUV5 promoter initiated with three purines (-1G, +1A and +2A; +1 representing the predominant start site) located 6-8 bp downstream from the Pribnow box. All the substitutions affected the start site selection, resulting in a change in the number of start sites (from 3 to 2 or 1) and/or a shift of the major start site (to -1 or +2). None of the variants started outside the 3-bp region and at the positions substituted by a pyrimidine. Purine-to-pyrimidine changes suppressed not only initiation at the substituted position but also, in some cases, at the other purine position. Purine-to-purine changes also shifted the major start site or suppressed the initiation at other sites. Changes at -2 and +5 also affected the start site selection. Thus, the sequence context around the initiation sites of lacUV5 promoter strongly influences the selection of initiating nucleotides by E. coli RNA polymerase.
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Affiliation(s)
- W Jeong
- Department of Life Science, Korea Advanced Institute of Science and Technology, Yusong-gu, Taejon
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