Dissemination of an international high-risk clone of Escherichia coli ST410 co-producing NDM-5 and OXA-181 carbapenemases in Seoul, Republic of Korea.

The rapid increase in carbapenemase-producing Enterobacterales is a global health concern. During 2017-2020, a total of 44 Escherichia coli isolates co-harbouring bla and bla were collected from patients at 17 hospitals in Seoul and characterized based on antimicrobial susceptibility, resistance genes and plasmid replicons detected using polymerase chain reaction (PCR). Clonal relatedness was estimated using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).

Distribution of mcr genes among carbapenem-resistant Enterobacterales clinical isolates: high prevalence of mcr-positive Enterobacter cloacae complex in Seoul, Republic of Korea.

Colistin is often used as a drug of last resort against infections caused by multi-drug-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacterales (CRE). Recently, the acquisition of mobile colistin resistance (mcr) genes by CRE has become a cause for concern. This study investigated the prevalence of mcr genes in CRE isolates in Seoul, Republic of Korea.

Identification of an extensively drug-resistant Escherichia coli clinical strain harboring mcr-1 and bla in Korea.

The development of colistin resistance in carbapenem-resistant strains poses a serious public health problem. In this study, we collected 249 carbapenem-resistant Escherichia coli isolates from patients in Seoul in 2018, and screened all isolates for colistin resistance and for the presence of mobile colistin resistance (mcr) genes. Colistin-resistant strains were further analyzed using multilocus sequence typing, antimicrobial susceptibility testing, detection of antibiotic resistance determinants, plasmid transconjugation, and whole-genome sequencing.

Influence of Mineral Supplementation on the Results from Analysis of Flavonol Glycoside Content in Dietary Supplements.

Flavonoids are a major component of extract (GBE). Several studies have investigated chelate formation and the redox reaction between flavonoids and metal ions; however, the effect of mineral supplements on the results from the analysis of the flavonol glycoside content in products containing GBE dietary supplement remains unknown. In this study, the effects of commonly used mineral supplements on the recovery of quercetin from GBE-containing dietary supplements were investigated using conventional methods of flavonol glycoside determination.

Concentrations of Bisphenols in Canned Foods and Their Risk Assessment in Korea.

The purpose of this study was to survey concentrations of bisphenols in canned foods using liquid chromatography-tandem mass spectrometry, to estimate the dietary exposure to bisphenols, and to assess the related risk for the Korean population from the intake of canned foods. The linearity of bisphenols in the range of 2.5 to 725 μg/L was satisfactory with correlation coefficients ( r) of 0.

Multivariate analysis to discriminate the origin of sesame seeds by multi-element analysis inductively coupled plasma-mass spectrometry.

In this study, inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the concentration of 15 elements (Mg, Al, K, Ca, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Cd, Ba, and Pb) of sesame seeds. Multivariate analysis was then performed to discriminate the origin of sesame seeds. Korean (48), Chinese (44), and Indian (21) samples were used to develop the calibration model.

Fluorescent indicators for simultaneous reporting of all four cell cycle phases.

A robust method for simultaneous visualization of all four cell cycle phases in living cells is highly desirable. We developed an intensiometric reporter of the transition from S to G2 phase and engineered a far-red fluorescent protein, mMaroon1, to visualize chromatin condensation in mitosis. We combined these new reporters with the previously described Fucci system to create Fucci4, a set of four orthogonal fluorescent indicators that together resolve all cell cycle phases.

A Comparison of Subtyping Methods for Differentiating Salmonella enterica Serovar Enteritidis Isolates Obtained from Food and Human Sources.

Purpose: To evaluate the abilities of these subtyping methods, we distinguished Salmonella Enteritidis (S. Enteritidis) isolated from food products and human clinical samples between 2009 and 2010 in Seoul using five subtyping methods.

Methods: We determined the subtypes of 20 S.

Rapid detection of exon 2-deleted AIMP2 mutation as a potential biomarker for lung cancer by molecular beacons.

Exon 2 deletion in aminoacyl tRNA synthetase complex-interacting multifunctional protein 2 (AIMP2) has been suggested to be associated with the progression of various cancers such as lung and ovarian cancers. However, few studies have been conducted regarding detection and relevance of exon 2-deleted AIMP2 (AIMP2-DX2) mutation to a specific cancer. Here, we demonstrate the rapid and simple detection of the AIMP2-DX2 mutation by molecular beacons and its relation to lung cancer.

Phenotypic characterization and random amplified polymorphic DNA (RAPD) analysis of Pasteurella multocida isolated from Korean pigs.

Pasteurella multocida causes various respiratory disease symptoms in pigs, including atrophic rhinitis and pneumonia. In the present study, 69 strains of P. multocida were isolated from 443 pigs with respiratory clinical symptoms at 182 farms located throughout South Korea from 2009 to 2010.

Treatment effects of microimplant-aided sliding mechanics on distal retraction of posterior teeth.

Introduction: Our objective was to quantify the treatment effects of microimplant-aided mechanics on group distal retraction of the posterior teeth.

Methods: The pretreatment and posttreatment cephalometric radiographs and dental casts of 23 patients (mean age, 22.1 ± 5.

Molecular characterization of partial-open reading frames 1a and 2 of the human astroviruses in South Korea.

Human astroviruses (HAstVs) are among the major causes of gastroenteritis in South Korea. In this study, the partial regions of the open reading frame (ORF) 1a and ORF2 genes of HAstVs from gastroenteritis patients in nine hospitals were sequenced, and the molecular characterization of the viruses was revealed. 89 partial nucleotide sequences of ORF1a and 88 partial nucleotide sequences of ORF2 were amplified from 120 stool specimens.

Rapid detection of the epidermal growth factor receptor mutation in non-small-cell lung cancer for analysis of acquired resistance using molecular beacons.

A secondary mutation (T790M) in epidermal growth factor receptor (EGFR) is a hallmark of acquired resistance to EGFR inhibitors used to treat non-small-cell lung cancer (NSCLC). Therefore, identifying the T790M mutation is crucial to guide treatment decisions. Given that DNA sequencing methods are time-consuming and insensitive, we developed and investigated the feasibility of using molecular beacons for the detection of the T790M mutation in EGFR.

Antimicrobial resistance patterns and characterization of integrons of Shigella sonnei isolates in Seoul, 1999-2008.

A total of 66 Shigella sonnei isolates from 1999 to 2008 in Seoul was analyzed for their antimicrobial resistance, carriage of integron, and the patterns of Pulsed-field gel electrophoresis (PFGE). A high level of antimicrobial resistance to streptomycin (100%), trimethoprim/sulfamethoxazole (95%), tetracycline (94%), nalidixic acid (65%), and ampicillin (41%) was observed among S. sonnei isolates.

Protein profiling in human sera for identification of potential lung cancer biomarkers using antibody microarray.

To identify potential biomarkers of lung cancer (LC), profiling of proteins in sera obtained from healthy and LC patients was determined using an antibody microarray. Based on our previous study on mRNA expression profiles between patients with LC and healthy persons, 19 proteins of interest were selected as targets for fabrication of an antibody microarray. Antibody to each protein and five nonspecific control antibodies were spotted onto a hydrogel-coated glass slide and used for profiling of proteins in sera of LC patients in a two-color fluorescence assay.

Analysis of in vitro SUMOylation using bioluminescence resonance energy transfer (BRET).

We demonstrated in vitro small ubiquitin-like modifier (SUMO)-mediated modification (SUMOylation) of RanGTPase activating protein-1 (RanGAP1) by using bioluminescence resonance energy transfer (BRET) for studying protein interactions. Renilla luciferase (Rluc) was fused to SUMO, and RanGAP1, the binding partner of SUMO, was fused to enhanced yellow fluorescence protein (EYFP). Upon binding of SUMO and RanGAP1, BRET was observed between EYFP (donor) and Rluc (acceptor) in the presence of E1 (Aos1/Uba2) and E2 (Ubc9) enzymes, whereas mutation (K524A) of RanGAP1 at its SUMO binding site prevented significant energy transfer.

On-chip detection of protein glycosylation based on energy transfer between nanoparticles.

We describe a chip-based method to detect protein glycosylation based on the energy transfer between quantum dots (QDs) and gold nanoparticles (AuNPs). Our assay system relies on modulations in the energy transfer between the nanoparticles on a surface. The photoluminescence (PL) of lectin-coated QDs (energy donor) immobilized on a glass slide is quenched by carbohydrate-coated AuNPs (energy acceptor), and the presence of the glycoprotein causes the increase of the PL of QDs.

Energy transfer-based multiplexed assay of proteases by using gold nanoparticle and quantum dot conjugates on a surface.

Rapid and sensitive assay of proteases and their inhibition in a high-throughput manner is of great significance in the diagnostic and pharmaceutical fields. We developed a multiplexed assay system of proteases and their inhibition by measuring the energy transfer between quantum dots (QDs) and gold nanoparticles (AuNPs) on a glass slide. In this system, while the photoluminescence (PL) of donor QDs immobilized on a surface was quenched due to the presence of AuNPs (energy acceptor) in close proximity, the protease activity caused modulation in the efficiency of the energy transfer between the acceptor and donor, thus enabling the protease assay.

Protein kinase assay on peptide-conjugated gold nanoparticles.

We demonstrate that protein kinase can be assayed with high sensitivity on peptide-conjugated gold nanoparticles (AuNPs). Phosphorylation of peptides on the AuNP-monolayers was detected by using an anti-phosphotyrosine antibody (alpha-pY) and Cy3-labeled secondary antibody (Cy3-alpha-mIgG) as a probing molecule. When compared to conventional self-assembled monolayers (SAMs), spherical and three-dimensional geometry of AuNPs led to high surface density of peptide substrate and easy accessibility to enzyme, and consequently the resulting AuNP monolayers gave rise to improved detection sensitivity.

Chip-based analysis of SUMO (small ubiquitin-like modifier) conjugation to a target protein.

A chip-based analysis of protein interactions and modifications in cell signaling pathways has been of great potential in drug discovery, diagnostics, and cell biology, because it enables rapid and high-throughput biological assays with a small amount of samples. We report a chip-based analysis of sumoylation, the post-translational modification (PTM) process that involves covalent attachment of the small ubiquitin-like modifier (SUMO) protein to a target protein through multiple enzyme reactions in eukaryotic cells. Substrate proteins were spotted onto a glass surface followed by the addition of the reaction mixture for sumoylation, and the SUMO conjugation was readily detected by using fluorescent dye-labeled antibody.