Biomedical subjects

Bon-Sung Koo

Publications and source records attributed to Bon-Sung Koo.

5 recordsLinked to original sources

PubMed2006

Idiomarina homiensis sp. nov., isolated from seashore sand in Korea.

A halophilic, aerobic bacterium, designated PO-M2(T), was isolated from seashore sand, from Pohang, Korea and characterized on the basis of physiological and biochemical features. Phylogenetic analysis of 16S rRNA gene sequences revealed a clear affiliation of the novel strain with members of the genus Idiomarina. Sequence similarities between strain PO-M2(T) and the type strains of species belonging to the genus Idiomarina ranged from 94.3 to 95.5 %. Cells of strain PO-M2(T) were straight or slightly curved rods and formed light-yellow colonies on marine agar medium. The major isoprenoid quinone was ubiquinone (Q-8) and the predominant cellular fatty acids were C(15 : 0) iso (19.3 %), C(17 : 1)omega9c iso (11.9 %), C(17 : 0) iso (10.9 %), C(18 : 1)omega7c (10.4 %), C(16 : 0) (9.0 %) and C(16 : 1)omega7c and/or C(15 : 0) iso 2-OH (7.2 %). The G+C content of the DNA was 45.1 mol%. Based on physiological, biochemical and chemotaxonomic traits and comparative 16S rRNA gene sequence analysis, it is demonstrated that the isolate represents a novel species of the genus Idiomarina, for which the name Idiomarina homiensis sp. nov. is proposed. The type strain is PO-M2(T) (=KACC 11514(T)=DSM 17923(T)).

Alteromonadaceae↗

PubMed2005

Development of high-throughput assay of lethal factor using native substrate.

The design of inhibitors for anthrax lethal factor (LF) is currently of interest as an approach for the treatment of anthrax because LF plays a major role in the cytotoxicity of target cells. LF is a zinc-dependent metalloprotease that specifically cleaves the mitogen-activated protein kinase kinase (MKK) family. Current assay systems for the screening of LF inhibitor use the optimized synthetic peptide coupled with various kinds of fluorophores, enabling fast, sensitive, and robust assays suited to high-throughput screening. However, evidence suggests that the regions beside the cleavage site are also involved in specificity and proteolytic activity of LF. In the current study, we tried to develop a high-throughput assay for LF activity based on native substrate, mitogen-activated ERK kinase 1 (MEK1). The assay system relies on the enhanced chemiluminescence signal resulting from a specific antibody against the C-terminal region of native substrate. A glutathione-coated multiwell plate was used as a solid support to immobilize the native substrate by its N-terminal glutathione-S-transferase moiety. Immobilized substrate increases the specificity and sensitivity of LF-catalyzed substrate hydrolysis compared with the solution phase assay. This assay system might be used to discover a wide spectrum of anthrax inhibitors.

Antigens, Bacterial↗

PubMed2005

The genome sequence of Xanthomonas oryzae pathovar oryzae KACC10331, the bacterial blight pathogen of rice.

The nucleotide sequence was determined for the genome of Xanthomonas oryzae pathovar oryzae (Xoo) KACC10331, a bacterium that causes bacterial blight in rice (Oryza sativa L.). The genome is comprised of a single, 4 941 439 bp, circular chromosome that is G + C rich (63.7%). The genome includes 4637 open reading frames (ORFs) of which 3340 (72.0%) could be assigned putative function. Orthologs for 80% of the predicted Xoo genes were found in the previously reported X.axonopodis pv. citri (Xac) and X.campestris pv. campestris (Xcc) genomes, but 245 genes apparently specific to Xoo were identified. Xoo genes likely to be associated with pathogenesis include eight with similarity to Xanthomonas avirulence (avr) genes, a set of hypersensitive reaction and pathogenicity (hrp) genes, genes for exopolysaccharide production, and genes encoding extracellular plant cell wall-degrading enzymes. The presence of these genes provides insights into the interactions of this pathogen with its gramineous host.

Base Sequence↗

PubMed2004

Targeting of Bacillus anthracis interaction factors for human macrophages using two-dimensional gel electrophoresis.

Bacillus anthracis, a gram-positive, endospore-forming, aerobic rod-shaped bacterium, interacts with macrophages at various stages of the disease. Spore germination and the outgrowth of vegetative bacilli are crucial steps enabling the bacteria to proliferate actively and to synthesize the virulence factors leading to a massive septicemia. In this study, we performed a proteomic analysis and MALDI-TOF/MS were carried out to identify proteins using human macrophages infected with the spores of B. anthracis live-Sterne or inactivated-Sterne. We identified 21 proteins which are related to the infection of B. anthracis spores on human macrophages at the early stage events. These proteins function in processes such as cytoskeleton regulation, apoptosis, cell division, and protein degradation. Proteins such as PAK 2 revealed a relationship to apoptosis in human macrophages. These proteins play an important role in the macrophage survival and death on human macrophages with infected B. anthracis spores.

Bacillus anthracis↗

PubMed2003

Production and proteolytic assay of lethal factor from Bacillus anthracis.

Bacillus anthracis is the causative agent of anthrax. The major virulence factors are a poly-D-glutamic acid capsule and three-protein component exotoxin, protective antigen (PA, 83 kDa), lethal factor (LF, 90 kDa), and edema factor (EF, 89 kDa), respectively. These three proteins individually have no known toxic activities, but in combination with PA form two toxins (lethal toxin or edema toxin), causing different pathogenic responses in animals and cultured cells. In this study, we constructed and produced rLF as a form of GST fusion protein in Escherichia coli. rLF was rapidly purified through a single affinity purification step to near homogeneity. Furthermore, we developed an in vitro immobilized proteolytic assay of LF under the condition containing full-length native substrate, MEK1, rather than short synthetic peptide. The availability of full-length substrate and of an immobilized LF assay could facilitate not only the in-depth investigation of structure-function relationship of the enzyme toward its substrate but also wide spectrum screening of inhibitor collections based on the 96-well plate system.

Amino Acid Sequence↗