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Antiseptic Effect of Ps-K18: Mechanism of Its Antibacterial and Anti-Inflammatory Activities
Jang, Mihee,Kim, Jieun,Choi, Yujin,Bang, JeongKyu,Kim, Yangmee MDPI AG 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.19
<P>Recently, bioactive peptides have attracted attention for their therapeutic applications in the pharmaceutical industry. Among them, antimicrobial peptides are candidates for new antibiotic drugs. Since pseudin-2 (Ps), isolated from the skin of the paradoxical frog Pseudis paradoxa, shows broad-spectrum antibacterial activity with high cytotoxicity, we previously designed Ps-K18 with a Lys substitution for Leu18 in Ps, which showed high antibacterial activity and low toxicity. Here, we examined the potency of Ps-K18, aiming to develop antibiotics derived from bioactive peptides for the treatment of Gram-negative sepsis. We first investigated the antibacterial mechanism of Ps-K18 based on confocal micrographs and field emission scanning electron microscopy, confirming that Ps-K18 targets the bacterial membrane. Anti-inflammatory mechanism of Ps-K18 was investigated by secreted alkaline phosphatase reporter gene assays and RT-PCR, which revealed that Ps-K18 activates innate defense via Toll-like receptor 4-mediated nuclear factor-kappa B signaling pathways. Moreover, we investigated the antiseptic effect of Ps-K18 using a lipopolysaccharide or Escherichia coli K1-induced septic shock mouse model. Ps-K18 significantly reduced bacterial growth and inflammatory responses in the septic shock model. Ps-K18 showed low renal and liver toxicity and attenuated lung damage effectively. This study suggests that Ps-K18 is a potent peptide antibiotic that could be applied therapeutically to Gram-negative sepsis.</P>
Wood Decay Fungi in South Korea: Polypores from Seoul
Jang, Yeongseon,Jang, Seokyoon,Lee, Jaejung,Lee, Hwanhwi,Lee, Hanbyul,Lee, Young Min,Hong, Joo-Hyun,Min, Mihee,Lim, Young Woon,Kim, Changmu,Kim, Jae-Jin The Korean Society of Mycology 2014 Mycobiology Vol.42 No.2
In Seoul, a majority of plant communities have undergone significant changes over the last few decades; however, how wood decay fungi have responded and adapted to the changes in vegetation remains unknown. Through an ongoing investigation of Korean indigenous fungi, ca. 300 specimens with poroid basidiocarp were collected in Seoul during 2008~2012. Morphological examination and molecular analysis using the internal transcribed spacer and nuclear large subunit ribosomal DNA region sequences helped identify 38 species belonging to 28 genera, 10 families, and 5 orders in this area. Among them, three polypores, Abundisporus pubertatis, Coriolopsis strumosa, and Perenniporia maackiae were found to be new to South Korea.
Wood Decay Fungi in South Korea: Polypores from Seoul
( Yeongseon Jang ),( Seokyoon Jang ),( Jaejung Lee ),( Hwanhwi Lee ),( Hanbyul Lee ),( Young Min Lee ),( Joo Hyun Hong ),( Mihee Min ),( Young Woon Lim ),( Changmu Kim ),( Jae Jin Kim ) 한국균학회 2014 韓國菌學會誌 Vol.42 No.2
In Seoul, a majority of plant communities have undergone significant changes over the last few decades; however, how wood decay fungi have responded and adapted to the changes in vegetation remains unknown. Through an ongoing investigation of Korean indigenous fungi, ca. 300 specimens with poroid basidiocarp were collected in Seoul during 2008~2012. Morphological examination and molecular analysis using the internal transcribed spacer and nuclear large subunit ribosomal DNA region sequences helped identify 38 species belonging to 28 genera, 10 families, and 5 orders in this area. Among them, three polypores, Abundisporus pubertatis, Coriolopsis strumosa, and Perenniporia maackiae were found to be new to South Korea.
Son, Yoonkook,Park, Mihee,Son, Yeonguk,Lee, Jung-Soo,Jang, Ji-Hyun,Kim, Youngsik,Cho, Jaephil American Chemical Society 2014 NANO LETTERS Vol.14 No.2
<P>This work has been performed to determine the critical size of the GeO<SUB>2</SUB> nanoparticle for lithium battery anode applications and identify its quantum confinement and its related effects on the electrochemical performance. GeO<SUB>2</SUB> nanoparticles with different sizes of ∼2, ∼6, ∼10, and ∼35 nm were prepared by adjusting the reaction rate, controlling the reaction temperature and reactant concentration, and using different solvents. Among the different sizes of the GeO<SUB>2</SUB> nanoparticles, the ∼6 nm sized GeO<SUB>2</SUB> showed the best electrochemical performance. Unexpectedly smaller particles of the ∼2 nm sized GeO<SUB>2</SUB> showed the inferior electrochemical performances compared to those of the ∼6 nm sized one. This was due to the low electrical conductivity of the ∼2 nm sized GeO<SUB>2</SUB> caused by its quantum confinement effect, which is also related to the increase in the charge transfer resistance. Those characteristics of the smaller nanoparticles led to poor electrochemical performances, and their relationships were discussed.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-2/nl404466v/production/images/medium/nl-2013-04466v_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl404466v'>ACS Electronic Supporting Info</A></P>
Kim, Yunok,Yoo, Jaeseung,Jang, Donghyuk,Muhammad, Shoaib,Jeong, Mihee,Choi, Woosung,Yoon, Won-Sub The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.28
<P>Olivine-type phosphates have become cathode materials of great interest in Li rechargeable batteries because of their low cost, high energy density and thermal safety. Strategies such as introduction of non-stoichiometric character, doping, carbon coating, and reduction of particle size have been shown to improve the electrochemical performances of olivine materials. However, the underlying mechanism responsible for electrochemical enhancement by introduction of non-stoichiometric character and doping is not yet well understood at the structure level. In this study, we investigated the structural and electrochemical properties of the equi-sized LiFe0.5Mn0.5PO4, non-stoichiometric LiFe0.5−xMn0.5−xPO4−σ and Cr-doped LiFe0.5−xMn0.5−xCryPO4−σ materials in depth by using synchrotron X-rays, neutrons and electrochemical techniques in order to explore the underpinning science responsible for improved electrochemistry of olivines as a result of non-stoichiometry and supervalent doping. Our neutron diffraction study revealed that anti-site defects are a critical factor for improving the electrochemical performance of olivines, and these defects can be decreased by introducing non-stoichiometry in the crystal structure. The X-ray absorption near edge structure results show that the improved electrochemical performance obtained in non-stoichiometric LiFe0.5−xMn0.5−xPO4−σ and Cr-doped LiFe0.5−xMn0.5−xCryPO4−σ is achieved by a selective further oxidation of Mn, and there is no effect of non-stoichiometry and doping on the Fe<SUP>2+</SUP>/Fe<SUP>3+</SUP> redox couple.</P>
Effects of C-Terminal Residues of 12-Mer Peptides on Antibacterial Efficacy and Mechanism
( Kkabi Son ),( Jieun Kim ),( Mihee Jang ),( Anil Kumar Chauhan ),( Yangmee Kim ) 한국미생물 · 생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.11
The development of new antimicrobial agents is essential for the effective treatment of diseases such as sepsis. We previously developed a new short peptide, Pap12-6, using the 12 N-terminal residues of papiliocin, which showed potent and effective antimicrobial activity against multidrug-resistant Gram-negative bacteria. Here, we investigated the antimicrobial mechanism of Pap12-6 and a newly designed peptide, Pap12-7, in which the 12<sup>th</sup> Trp residue of Pap12-6 was replaced with Val to develop a potent peptide with high bacterial selectivity and a different antibacterial mechanism. Both peptides showed high antimicrobial activity against Gram-negative bacteria, including multidrug-resistant Gram-negative bacteria. In addition, the two peptides showed similar anti-inflammatory activity against lipopolysaccharidestimulated RAW 264.7 cells, but Pap12-7 showed very low toxicities against sheep red blood cells and mammalian cells compared to that showed by Pap12-6. A calcein dye leakage assay, membrane depolarization, and confocal microscopy observations revealed that the two peptides with one single amino acid change have different mechanisms of antibacterial action: Pap12-6 directly targets the bacterial cell membrane, whereas Pap12-7 appears to penetrate the bacterial cell membrane and exert its activities in the cell. The therapeutic efficacy of Pap12-7 was further examined in a mouse model of sepsis, which increased the survival rate of septic mice. For the first time, we showed that both peptides showed anti-septic activity by reducing the infiltration of neutrophils and the production of inflammatory factors. Overall, these results indicate Pap12-7 as a novel non-toxic peptide with potent antibacterial and anti-septic activities via penetrating the cell membrane.