Pathogenesis of Enterohemorrhagic <i>Escherichia coli</i> O157:H7 is mediated by the cytochrome P450 family in <i>Caenorhabditis elegans</i> animal model

Ryu, S.,Oh, S.,Park, M.R.,Lee, W.J.,Yun, B.,Choi, H.J.,Oh, M.H.,Oh, N.S.,Song, M.H.,Kim, Y. BUTTERWORTH-HEINEMANN 2019 FOOD CONTROL Vol.103 No.-

<P><B>Abstract</B></P> <P>Foodborne pathogens, including enterohemorrhagic <I>Escherichia coli</I> (EHEC) O157:H7, may enter from the farm environment and foods via several different vectors and influence human health. Here, we employed <I>Caenorhabditis elegans</I> as a host model system and compared specific host responses during EHEC O157:H7 infection using whole-transcriptome analysis. To elucidate the immune pathways stimulated by EHEC O157:H7, we employed quantitative real-time polymerase chain reaction (qRT-PCR), transgenic worms, and RNAi. Whole-transcriptome analysis revealed that genes encoding the cytochrome P450 (CYP450) family were induced more than 10-fold during EHEC O157:H7 infection in <I>C. elegans</I> host models. Importantly, <I>C. elegans</I> mutants lacking CYP450 genes were highly susceptible to EHEC O157:H7 infection compared with wild-type N2 worms. Consistent with susceptibility tests, qRT-PCR results indicated that CYP450 loss-of-function mutations significantly affected the transcriptional induction of antimicrobial peptide genes, such as <I>clec-60</I>. Together, our results provide critical insights into host strategies for avoiding EHEC O157:H7 pathogenesis in the gastrointestinal tract via the cytochrome P450 family and highlights potential molecular targets for preventing the virulence of EHEC O157:H7 in foods.</P>

Potent selective monoamine oxidase B inhibition by maackiain, a pterocarpan from the roots of Sophora flavescens

Lee, H.W.,Ryu, H.W.,Kang, M.G.,Park, D.,Oh, S.R.,Kim, H. Pergamon Press 2016 Bioorganic & medicinal chemistry letters Vol.26 No.19

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines and its two isoforms, MAO-A and MAO-B, break down neurotransmitter amines. Of the compounds isolated from the roots of Sophora flavescens, (-)-maackiain (4), a pterocarpan, was found to potently and selectively inhibit human MAO-B, with an IC<SUB>50</SUB> of 0.68μM, and to have a selectivity index of 126.2 for MAO-B. As compared with other herbal natural products, the IC<SUB>50</SUB> value of 4 for MAO-B is one of the lowest reported to date. Genistein (1) highly, effectively and non-selectively inhibited MAO-A and MAO-B with IC<SUB>50</SUB> values of 3.9μM and 4.1μM, respectively. (-)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan (2) effectively and non-selectively inhibited MAO-A and MAO-B with IC<SUB>50</SUB> values of 20.3μM and 10.3μM, respectively. In addition, compound 4 reversibly and competitively inhibited MAO-B with a K<SUB>i</SUB> value of 0.054μM. Molecular docking simulation revealed that the binding affinity of 4 for MAO-B (-26.6kcal/mol) was greater than its affinity for MAO-A (-8.3kcal/mol), which was in-line with our inhibitory activity findings. Furthermore, Cys172 of MAO-B was found to be a key residue for hydrogen bonding with compound 4. The findings of this study suggest compound 4 be viewed as a new potent, selective, and reversible MAO-B inhibitor, and that compounds 1 and 2 be considered useful lead compounds for the developments of nonselective and reversible MAO inhibitors for the treatment of disorders like Parkinson's disease, Alzheimer disease, and depression.

Coumarins reduce biofilm formation and the virulence of Escherichia coli O157:H7

Lee, J.H.,Kim, Y.G.,Cho, H.S.,Ryu, S.Y.,Cho, M.H.,Lee, J. G. Fischer 2014 Phytomedicine Vol.21 No.8

E. coli O157:H7 is the most common cause of hemorrhagic colitis, and no effective therapy exists for E. coli O157:H7 infection. Biofilm formation is closely related to E. coli O157:H7 infection and constitutes a mechanism of antimicrobial resistance. Hence, the antibiofilm or antivirulence approach provides an alternative to antibiotic strategies. Coumarin and its derivatives have a broad range of biological effects, and in this study, the antibiofilm activities of nine coumarins were investigated against E. coli O157:H7. Coumarin or umbelliferone at 50μg/ml was found to inhibit biofilm E. coli O157:H7 formation by more than 80% without affecting bacterial growth. Transcriptional analysis showed that coumarins repressed curli genes and motility genes in E. coli O157:H7, and these findings were in-line with observed reductions in fimbriae production, swarming motility, and biofilm formation. In addition, esculetin repressed Shiga-like toxin gene stx2 in E. coli O157:H7 and attenuated its virulence in vivo in the nematode Caenorhabditis elegans. These findings show that coumarins have potential use in antivirulence strategies against persistent E. coli O157:H7 infection.

Sanitizing radish seeds by simultaneous treatments with gaseous chlorine dioxide, high relative humidity, and mild heat

Bang, J.,Choi, M.,Son, H.,Beuchat, L.R.,Kim, Y.,Kim, H.,Ryu, J.H. Elsevier Science Publishers 2016 International journal of food microbiology Vol.237 No.-

<P>Sanitizing radish seeds intended for edible sprout production was achieved by applying simultaneous treatments with gaseous chlorine dioxide (ClO2), high relative humidity (RH, 100%), and mild heat (55 degrees C). Gaseous ClO2 was produced from aqueous ClO2 (0.66 ml) by mixing sulfuric acid (5% w/v) with sodium chlorite (10 mg/mL) in a sealed container (1.8 L). Greater amounts of gaseous ClO2 were measured at 23% RH (144 ppm after 6 h) than at 100% RH (66 ppm after 6 h); however, the lethal activity of gaseous ClO2 against naturally occurring mesophilic aerobic bacteria (MAB) on radish seeds was significantly enhanced at 100% RH. For example, when exposed to gaseous ClO2 at 23% RH, the number of MAB on radish seeds decreased from 3.7 log CFU/g to 2.6 log CFU/g after 6 h. However, when exposed to gaseous ClO2 at 100% RH for 6 h, the MAB population decreased to 0.7 log CFU/g after 6 h. Gaseous ClO2 was produced in higher amounts at 55 degrees C than at 25 degrees C, but decreased more rapidly over time at 55 degrees C than at 25 degrees C. The lethal activity of gaseous ClO2 against MAB on radish seeds was greater at 55 degrees C than at 25 degrees C. When radish seeds were treated with gaseous ClO2 (peak concentration: 195 ppm) at 100% RH and 55 degrees C, MAB were reduced to populations below the detectable level (<-0.7 log CFU/g) within 2 h without decreasing the seed germination rate (97.7%). The lethality of combined treatments against artificially inoculated Escherichia coli O157:H7 was also evaluated. When exposed to gaseous ClO2 at 100% RH and 55 degrees C for 6 h, the initial number of E. coli O157:H7 (3.5 log CFU/g) on radish seeds decreased to below the detection limit (0.7 log CFU/g) by direct plating but it was not eliminated from seeds. The germination rate of radish seeds was not significantly (P> 0.05) decreased after treatment for 6 h. The information reported here will be useful when developing decontamination strategies for producing microbiologically safe radish seed sprouts. (C) 2016 Published by Elsevier B.V.</P>

The influence of flavonoid compounds on the in vitro inhibition study of a human fibroblast collagenase catalytic domain expressed in E. coli

Nguyen, T.T.H.,Moon, Y.H.,Ryu, Y.B.,Kim, Y.M.,Nam, S.H.,Kim, M.S.,Kimura, A.,Kim, D. IPC Science and Technology Press ; Elsevier Scienc 2013 Enzyme and microbial technology Vol.52 No.1

The human fibroblast collagenase catalytic domain (MMP1ca) that is considered a prototype for all interstitial collagenase and plays an important role in the turnover of collagen fibrils in the matrix was expressed as an inclusion body in the Escherichia coli. The purified enzyme displayed activity with substrate Dnp-Pro-Leu-Ala-Leu-Trp-Ala-Arg-OH with a K<SUB>m</SUB> value of 26.61+/-1.42μM. The inhibition activity of the nine flavonoid compounds and gallic acid against MMP1ca was examined. Among the compounds tested, the IC<SUB>50</SUB> of seven flavonoid compounds were determined and ranged from 14.13 to 339.21μM. Epigallocatechin gallate (EGCG) showed the highest inhibition toward MMP1ca with IC<SUB>50</SUB> values of 14.13+/-0.49μM. EGCG showed a competitive inhibition pattern with a K<SUB>i</SUB> value of 10.47+/-0.51μM. The free binding energy of EGCG against MMP1ca was -13.07kcalmol<SUP>-1</SUP>, which was calculated by using Autodock 3.0.5 software and showed numerous hydrophobic and hydrogen bond interactions. The galloyl group of EGCG, gallocatechin gallate and epicatechin gallate was determined to be important for inhibitory activity against MMP1ca.

Detection and Identification of Mycobacterium tuberculosis in Joint Biopsy Specimens by rpoB PCR Cloning and Sequencing

Yun, Y.-J.,Lee, K.-H.,Haihua, L.,Ryu, Y.-J.,Kim, B.-J.,Lee, Y.-H.,Baek, G.-H.,Kim, H.-J.,Chung, M.-S.,Lee, M.-C.,Lee, S.-H.,Choi, I.-H.,Cho, T.-J.,Chang, B.-S.,Kook, Y.-H. American Society for Microbiology 2005 Journal of clinical microbiology Vol.43 No.1

<P>Osteoarticular tuberculosis (OAT) is an extrapulmonary tuberculosis and accounts for 1 to 3% of all tuberculosis cases. We used an rpoB PCR-plasmid TA cloning-sequencing method to detect and identify tubercle bacilli in surgical specimens from patients suspected of having OAT. By comparing the similarities of the rpoB sequences determined with those in GenBank, Mycobacterium tuberculosis was detected in 23 of 43 samples. Three of the 23 positive samples had mutations at codon 531, which are commonly observed in rifampin-resistant M. tuberculosis strains. Our results suggest that the rpoB PCR-TA cloning-sequencing method developed, which detects M. tuberculosis and which simultaneously determines its rifampin susceptibility, can also be used efficiently for the diagnosis of OAT.</P>

An electric powertrain modelling of a full cell hybrid electric vehicle and development of a power distribution algorithm using H_[unknown] control

Ryu, J.-H.,Lee, H.-J.,Sunwoo, M.-H. Professional Engineering Publishing 2010 Proceedings of the Institution of Mechanical Engin Vol.224 No.8

<P>This paper presents an electric powertrain model of a parallel-type fuel cell hybrid electric vehicle (FCHEV) and its robust H-infinity controller for efficient power distribution between a fuel cell and a battery. The electric powertrain of the parallel-type FCHEV is composed of a fuel cell stack system, a d.c.-to-d.c. converter, and a battery. The fuel cell stack system is connected to the battery through the d.c.-to-d.c. converter, which is a key component for power distribution between the fuel cell and the battery. In this study, the electric powertrain model of the FCHEV was derived from the dynamic differential equations of the equivalent-circuit model that describes the electric powertrain. Using this model, the robust H-infinity controller was designed to control the power distribution between the fuel cell and the battery efficiently. Finally, the results of driving-cycle simulation verified the performance of the proposed robust H-infinity controller.</P>

Photoluminescent europium(III) complex intercalated in natural and synthetic clay minerals for enhanced latent fingerprint detection

Ryu, S.J.,Kim, A.,Kim, M.D.,Hong, S.W.,Min, S.S.,Lee, J.H.,Lee, J.K.,Jung, H. Elsevier 2014 Applied clay science Vol.101 No.-

Fluorescent nanohybrid materials, europium(III) complex intercalated Na<SUP>+</SUP>-smectite clay minerals (synthetic hectorite and natural montmorillonite), have been developed to visualize latent fingerprints. The guest europium(III) complex ([EuCl<SUB>2</SUB>(Phen)<SUB>2</SUB>(H<SUB>2</SUB>O)<SUB>2</SUB>]Cl.H<SUB>2</SUB>O) was obtained by simple complex reaction between europium chloride hexahydrate (EuCl<SUB>3</SUB>.6H<SUB>2</SUB>O) and 1,10-phenanthroline (Phen) as a 1:2 molar ratio of Eu<SUP>3+</SUP> ion to ligand molecules. The intercalated nanohybrids ([Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-clay minerals) were obtained through ion exchange reaction of interlayer sodium cation with europium complex ion. Guest europium(III) complex and [Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-clay mineral hybrids were characterized by powder X-ray diffraction, Fourier transform infrared, thermogravimetry-differential thermal analysis (TG-DTA), elemental analysis, UV-visible and fluorescence spectroscopy. The intercalated complex maintains a characteristic red <SUP>5</SUP>D<SUB>0</SUB>-<SUP>7</SUP>F<SUB>2</SUB> emission at wavelength 617nm, which is comparable to that of the free complex. The <SUP>5</SUP>D<SUB>0</SUB>-<SUP>7</SUP>F<SUB>2</SUB> emission intensity of [Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-laponite was ca. 3.5 times higher than that of [Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-montmorillonite, due to the presence of quenching impurities in natural montmorillonite itself. Fingerprint residues on glass slides were harvested by using [Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-clay mineral powders, resulting in good definition for enhanced latent fingerprint detection. Particularly, [Eu(Phen)<SUB>2</SUB>]<SUP>3+</SUP>-hectorite hybrid powder was more clearly separated from the background compared to the montmorillonite hybrid powder.

Impaired expression of Toll-like receptor 2 in nontuberculous mycobacterial lung disease.

Ryu, Y J,Kim, E J,Lee, S-H,Kim, S Y,Suh, G Y,Chung, M P,Kim, H,Kwon, O J,Koh, W-J Published jointly by the Society and Munksgaard 2007 The European respiratory journal Vol.30 No.4

<P>The aims of the present study were to investigate the expression of Toll-like receptor (TLR)2 on the peripheral blood monocytes of patients with nontuberculous mycobacterial (NTM) lung disease and healthy controls, and to assess the responses of these monocytes to TLR2 agonists such as Mycobacterium avium and lipoteichoic acid (LTA). Reverse transcriptase-PCR was used to analyse TLR2 mRNA expression in peripheral blood monocytes from 17 NTM patients and 10 healthy controls. mRNA and protein secretion levels were also determined for the cytokines interleukin (IL)-12 p40 and tumour necrosis factor (TNF)-alpha. Expression of TLR2 mRNA by peripheral blood monocytes after stimulation with M. avium or LTA was lower in NTM patients than in healthy controls. IL-12 p40 and TNF-alpha mRNA and cytokine secretion levels were also lower in patients than in healthy controls. Treatment with anti-TLR antibody decreased M. avium- and LTA-induced IL-12 p40 and TNF-alpha production in healthy controls, but not in NTM patients. The present results suggest that the downregulation of Toll-like receptor 2 and the resulting decreased production of interleukin-12 p40 and tumour necrosis factor-alpha following Mycobacterium avium or lipoteichoic acid stimulation may contribute to host susceptibility to nontuberculous mycobacterial lung disease.</P>

Suppression of miRNA-708 by Polycomb Group Promotes Metastases by Calcium-Induced Cell Migration

Ryu, S.,McDonnell, K.,Choi, H.,Gao, D.,Hahn, M.,Joshi, N.,Park, S.M.,Catena, R.,Do, Y.,Brazin, J.,Vahdat, Linda T.,Silver, Randi B.,Mittal, V. Cell Press 2013 Cancer cell Vol.23 No.1

The progression of cancer to metastatic disease is a major cause of death. We identified miR-708 being transcriptionally repressed by polycomb repressor complex 2-induced H3K27 trimethylation in metastatic breast cancer. miR-708 targets the endoplasmic reticulum protein neuronatin to decrease intracellular calcium level, resulting in reduction of activation of ERK and FAK, decreased cell migration, and impaired metastases. Ectopic expression of neuronatin refractory to suppression by miR-708 rescued cell migration and metastasis defects. In patients with breast cancer, miR-708 expression was decreased in lymph node and distal metastases, suggesting a metastasis-suppressive role. Our findings uncover a mechanistic role for miR-708 in metastasis and provide a rationale for developing miR-708 as a therapeutic agent against metastatic breast cancer.