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Induction of the pneumococcal <i>vncRS</i> operon by lactoferrin is essential for pneumonia
Lee, Seungyeop,Ghosh, Prachetash,Kwon, Hyogyoung,Park, Sang-Sang,Kim, Gyu-Lee,Choi, Sang-Yoon,Kim, Eun-Hye,Tran, Thao Dang-Hien,Seon, Seung Han,Le, Nhat Tu,Iqbal, Hamid,Lee, Sangho,Pyo, Suhkneung,Rhee TaylorFrancis 2018 Virulence Vol.9 No.1
<P><B>ABSTRACT</B></P><P><I>Streptococcus pneumoniae</I> (pneumococcus), the major pathogen for pneumonia, commonly colonizes the lung, but the mechanism underlying the coordination of virulence factors during invasion via the host protein remains poorly understood. Bacterial lysis releases the components of the cell wall, and triggers innate immunity and the subsequent secretion of pro-inflammatory cytokines. Previously, the virulence of the <I>pep27</I> mutant was shown to be attenuated as a feasible candidate for vaccine development. However, the role of <I>pep27</I> gene, belonging to the vancomycin-resistance locus (<I>vncRS</I> operon), in virulence, is largely unknown. This study demonstrates that transferrin in the host serum reduces the survival of the host during <I>S. pneumoniae</I> infections in mice. The exposure of the pneumococcal D39 strain to lactoferrin induced the <I>vncRS</I> operon, lysis, and subsequent <I>in vivo</I> cytokine production, resulting in lung inflammation. However, these responses were significantly attenuated in pneumococci harboring a mutation in <I>pep27</I>. Mechanistically, the VncS ligand, identified as lactoferrin, induced the <I>vncRS</I> operon and increased the <I>in vivo</I> mortality rates. Thus, serum-induced activation of <I>vncRS</I> plays an essential role in inducing pneumonia.</P>
Detection of Silver Ions Using Dielectrophoretic Tweezers-Based Force Spectroscopy
Choi, Seungyeop,Lee, Gyudo,Park, In Soo,Son, Myeonggu,Kim, Woong,Lee, Hyungbeen,Lee, Sei-Young,Na, Sungsoo,Yoon, Dae Sung,Bashir, Rashid,Park, Jinsung,Lee, Sang Woo American Chemical Society 2016 ANALYTICAL CHEMISTRY - Vol.88 No.22
<P>Understanding of the interactions of silver ions (Ag+) with polynucleotides is important not only to detect Ag+ over a wide range of concentrations in a simple, robust, and high-throughput manner but also to investigate the intermolecular interactions of hydrogen and coordinate interactions that are generated due to the interplay of Ag+, hydrogen ions (H+), and polynucleotides since it is critical to prevent adverse environmental effects that may cause DNA damage and develop strategies to treat this damage. Here, we demonstrate a novel approach to simultaneously detect Ag+ satisfying the above requirements and examine the combined intermolecular interactions of Ag+-polycytosine and H+-polycytosine DNA complexes using dielectrophoretic tweezers-based force spectroscopy. For this investigation, we detected Ag+ over a range of concentrations (1 nM to 100 mu M) by quantifying the rupture force of the combined interactions and examined the interplay between the three factors (Ag+, H+, and polycytosine) using the same assay for the detection of Ag+. Our study provides a new avenue not only for the detection of heavy metal ions but also for the investigation of heavy metal ions-polynucleotide DNA complexes using the same assay.</P>
Lee, Si-On,Lee, Seungyeop,Kim, Se-Jin,Rhee, Dong-Kwon The Korean Society of Ginseng 2019 Journal of Ginseng Research Vol.43 No.2
Background: Streptococcus pneumoniae, more than 90 serotypes of which exist, is recognized as an etiologic agent of pneumonia, meningitis, and sepsis associated with significant morbidity and mortality worldwide. Immunization with a pneumococcal pep27 mutant (${{\Delta}}pep27$) has been shown to confer comprehensive, long-term protection against even nontypeable strains. However, ${{\Delta}}pep27$ is effective as a vaccine only after at least three rounds of immunization. Therefore, treatments capable of enhancing the efficiency of ${{\Delta}}pep27$ immunization should be identified without delay. Panax ginseng Mayer has already been shown to have pharmacological and antioxidant effects. Here, the ability of Korean Red Ginseng (KRG) to enhance the efficacy of ${{\Delta}}pep27$ immunization was investigated. Methods: Mice were treated with KRG and immunized with ${{\Delta}}pep27$ before infection with the pathogenic S. pneumoniae strain D39. Total reactive oxygen species production was measured using lung homogenates, and inducible nitric oxide (NO) synthase and antiapoptotic protein expression was determined by immunoblotting. The phagocytic activity of peritoneal macrophages was also tested after KRG treatment. Results: Compared with the other treatments, KRG significantly increased survival rate after lethal challenge and resulted in faster bacterial clearance via increased phagocytosis. Moreover, KRG enhanced ${{\Delta}}pep27$ vaccine efficacy by inhibiting reactive oxygen species production, reducing extracellular signal-regulated kinase apoptosis signaling and inflammation. Conclusion: Taken together, our results suggest that KRG reduces the time required for immunization with the ${{\Delta}}pep27$ vaccine by enhancing its efficacy.
Tomographic imaging of pore networks and connectivity of surfactant-directed mesoporous zeolites
Lee, Seungyeop,Jo, Changbum,Ryoo, Ryong The Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.22
<P>Zeolites of MFI, MTW, *MRE and beta frameworks were synthesized by a method using micropore-mesopore dual generating surfactants. The porous texture of the zeolites was characterized by electron tomography and argon adsorption after the removal of the surfactant by calcination. For high-contrast tomography, the zeolites were supported with platinum. The resultant tomograms showed disordered and interconnected networks of Pt nanowires and nanosheets, which corresponded to the shape of the surfactant-directed mesopores. In the calcined zeolites, both the mesopores and zeolitic micropores were fully accessible for argon adsorption. Before calcination, however, no pores were accessible even after being thoroughly washed with solvent. The result indicated that the surfactant head could be tightly encased within the micropores after guiding the formation of the zeolite framework as a part of the mesopore wall, so that the surfactant was difficult to remove by solvent washing. After calcination, the micropores and mesopores could be connected through an aperture in which the neck of the surfactant molecule had been located. Neohexane was adsorbed very rapidly due to the micropore-mesopore connectivity. The hierarchical pore connectivity is an important and characteristic feature of the surfactant-directed zeolites for application in high performance adsorption and catalysis.</P>
Seungyeop Lee,Dong-Kwon Rhee 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.4
Ginseng effectively regulates the immune response and the hormonal changes due to stress, thus maintaining homeostasis. In addition to suppressing the occurrence of psychological diseases such as anxiety and depression, ginseng also prevents stress-associated physiological diseases. Recent findings have revealed that ginseng is involved in adjusting the hypothalamicepituitaryeadrenal axis and controlling hormones, thus producing beneficial effects on the heart and brain, and in cases of bone diseases, as well as alleviating erectile dysfunction. Recent studies have highlighted the potential use of ginseng in the prevention and treatment of chronic inflammatory diseases such as diabetes, rheumatoid arthritis, and allergic asthma. However, the mechanism underlying the effects of ginseng on these stress-related diseases has not been completely established. In this review, we focus on the disease pathways caused by stress in order to determine how ginseng acts to improve health. Central to our discussion is how this effective and stable therapeutic agent alleviates the anxiety and depression caused by stress and ameliorates inflammatory diseases.
Study on the exchange reaction of HDTMA with the inorganic cations in reference montmorillonties
SeungYeop Lee,SooJin Kim 한국지질과학협의회 2003 Geosciences Journal Vol.7 No.3
The adsorption of hexadecyltrimethylamonium(HDTMA) cations on swelling layer silicates (montmorilonites)was studied by adsorption isotherms, X-ray diffraction, and electronmicroscopy. At low HDTMA concentrations, HDTMA ions startedto be adsorbed on interlayer sites of SWy montmorilonite, causinga preferential release of interlayer Na+ compared with Ca2+, whilethe lateral attraction betwen adsorbed HDTMA cations at edges orexternal surfaces highly prevailed in SAz montmorillonite. Mont-morilonite clay surfaces appeared as foliated and iregular aggre-gate structures at high HDTMA loadings. Besides the clay surfacecharge, the interlayer inorganic cations appeared to have a sub-stantial influence on the expansion behavior of silicate layers aswell as the evolution of the surface aggregates as a function ofHDTMA surface coverage.