Jung Ho Ko

Heterogeneous expression of Chlamydia pneumoniae antigen candidates and high-level soluble expression of its inclusion membrane proteins in Escherichia coli

Chlamydia pneumoniae is an intracellular bacterium associated with several acute respiratory diseases and is an obligate intracellular parasite in eukaryotic cells. Heterogeneous and overexpression of virulence-associated C. pneumoniae “effector” proteins with structurally designed epitope-focused antigens in recombinant forms in Escherichia coli is a prerequisite in the study of the organism’s pathogenic mechanisms and for use in medical applications such as vaccine and therapeutics development. In this study, seven antigen candidates from C. pneumoniae TW-183 (OmpH, Omp11, Eno, ArtJ, IncA, IncB and IncC) were screened in silico genome. Immunogenicity of the heterogeneously overexpressed antigen candidates in E. coli BL21 (DE3) was investigated by Western blot analysis using in sera from C. pneumoniae infected individuals. The soluble forms of three inclusion membrane proteins (IncA, IncB and IncC), carrying unique bilobal hydrophobic domains, were also successfully expressed in E. coli BL21 (DE3) through truncation of their membrane bound transmembrane domains.

Aptasensor for environmental monitoring

Aptamers are single-stranded oligonucleotides (DNA or RNA) capable of folding into well-defined structures and motifs that allow them bind to various target molecules with high specificity and affinity. The crucial ability of aptamers is interaction with a given target from small ions to molecular level that makes them useful in many applications for specific detection of various analytes. Nowadays aptamer is an effective tool not only for in vitro research in diagnostic methods, drug delivery and treatment therapy, but also for the development of nucleic-acid-based sensors in industrial waste management, pollution control and environmental toxicology. This mini review is focused on discussion and updating about the global researches in nucleic-acid-based sensors for environmental issues.

Daphnia in water quality biomonitoring - “omic” approaches

Along with the global industrialization, the problem of pollution has spread, especially the water pollution. Pollutants in many types (chemical, physical, radio-active or pathogenic microbial substances) enter natural water bodies such as lakes, rivers, oceans and so on, degrading the quality of water that has the harmful effects on several aquatic species living in it. As a result, many attempts have been made to develop the monitoring techniques to improve the ability of detecting more pollutants in shorter time, and at lower concentrations. Biological monitoring, or biomonitoring is a valuable assessment tool that receiving increased use in water quality monitoring programs, in which biochemical, genetic, morphological, and physiological changes in indicator species have been noted as being related to particular environmental stressors. Daphnia, a freshwater crustacean, has been extensively used as a model organism for toxicity testing and its toxicological reactions to environmental pollutants have been being well characterized. Together with this, achievements in genetic technology bring an advanced tool for studying water biomonitoring using this invertebrate. In the present review, the ability of using Daphnia in aquatic toxicological monitoring depending on “omic” approaches has been discussed shortly.

Proteomic Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) Degradation and Detoxification in Sphingobium chungbukense DJ77.

Polycyclic aromatic hydrocarbons (PAHs) are commonly present xenobiotics in natural and contaminated soils. We studied three (phenanthrene, naphthalene, and biphenyl) xenobiotics, catabolism, and associated proteins in Sphingobium chungbukense DJ77 by two-dimensional gel electrophoresis (2-DE) analysis. Comparative analysis of the growth-dependent 2-DE results revealed that the intensity of 10 protein spots changed identically upon exposure to the three xenobiotics. Among the upregulated proteins, five protein spots, which were putative dehydrogenase, dioxygenase, and hydrolase and involved in the catabolic pathway of xenobiotic degradation, were induced. Identification of these major multifunctional proteins allowed us to map the multiple catabolic pathway for phenanthrene, naphthalene, and biphenyl degradation. A part of the initial diverse catabolism was converged into the catechol degradation branch. Detection of intermediates from 2,3-dihydroxy-biphenyl degradation to pyruvate and acetyl-CoA production by LC/MS analysis showed that ring-cleavage products of PAHs entered the tricarboxylic acid cycle, and were mineralized in S. chungbukense DJ77. These results suggest that S. chungbukense DJ77 completely degrades a broad range of PAHs via a multiple catabolic pathway.

The global research trend of porcine reproductive and respiratory syndrome virus (PRRSV): A mini review

The Porcine reproductive and respiratory syndrome (PRRS) is a significantly harmful illness in swine causing respiratory problems and reproductive failure in sows, gilts, and pneumonia in young pigs. PRRS is often diagnosed with available test methods to identify disease agent or to detect the immune response of virus. In spite of many extensive researches, there are still no specific treatments and many unknown relationships between this virus and other diseases in swine. Virus isolation and molecular techniques are possible to identify PRRS virus or its acid nucleic but the high genetic diversity of virus results to unwanted false-negative results. Although PRRS has spreads throughout the world, many researches still focus on updating the methods to quickly diagnose PRRSV and to generate an effective fast treatment. This review highlights the current global PRRS research trend, its detection and diagnosis.

Lactic Acid Bacteria Isolated from Kimchi to Evaluate Anti-obesity Effect in High Fat Diet-induced Obese Mice

Obesity is one of the major public concerns due to its various side-effects such as metabolic and chronic ailments. In this study, two lactic acid bacteria (LAB) strains, Leuconostoc mesenteroides and Lactobacillus sakei, isolated from Kimchi were investigated for their anti-obesity activity in obese mice model. To induce obesity in model mice (C57BL/6), high fat diet (HFD) with 60 kcal% fat was fed for 10 weeks. LAB supplementation reduced blood urea nitrogen, glucose, and triglyceride levels in serum from obesity induced mice. The study also observed significant decrease of fibrosis, triglyceride, and total cholesterol level in fatty liver tissue by LAB supplementation. The results suggest that supplementation of L. mesenteroides and L. sakei could be used as alternative nutritional interventions to decrease symptoms caused by obesity with no safety or intolerance related problem.

Proteomic analysis of muscarinic acetylcholine receptor-mediated proliferation in HT-29 human colon cancer cells

BackgroundsMuscarinic acetylcholine receptors (mAChRs) are members of G-protein-coupled receptors. They can induce agonist-dependent neoplastic transformation and facilitate colon cancer proliferation via promoting rapid expression of a variety of early responsive genes.MethodsIn this study, we used 2-dimensional gel electrophoresis (2-DE) approach with subsequent mass spectrometry (MS) to identify up- and down-regulated proteins (a total of 23 protein spots) involved in mAChRs-related signaling pathway, energy metabolism, transcription/translation, oxidative stress metabolism and cytoskeleton organization in agonist carbachol stimulated HT-29 human colon cells.ResultsWe found that the increased expression of adenocarcinoma biomarker, annexin A5 (ANXA5) induced by carbachol treatment, which was confirmed by immunoblot. This study contributes to the understanding of mechanisms underlying mAChRs agonist-induced expression of whole proteins in HT-29 colon cancer cells.ConclusionOur results indicated that ANXA5 might serve as a potential biomarker for the diagnosis of colon cancer.

Aptamer-Immobilized Surface Plasmon Resonance Biosensor for Rapid and Sensitive Determination of Virulence Determinant

Shigella sonnei isolate invasion plasmid antigen protein, IpaH, was successfully expressed in recombinant overexpression bacterial system. The soluble expression IpaH was enhanced with molecular chaperon co-expressed environment. Specific aptamer IpaH17 was isolated through the SELEX process and showed fM binding affinity. IpaH17-SPR biosensor platform was involved to verify the binding sensitivity and specificity. The IpaH concentration dependent IpaH17-SPR sensor response was highly linear with a linear regression constant of 99.4% in the range between 0 and 100 ng/mL. In addition, S. sonnei revealed the specific RU value and detected in a real-time manner within 1 hour. Our study indicated that IpaH17-SPR sensor can allow for rapid, sensitive and specific determination of Shigella sonnei virulent factor.

Aptamer-Based Paper Strip Sensor for Detecting Vibrio fischeri

Aptamer-based paper strip sensor for detecting Vibrio fischeri was developed. Our method was based on the aptamer sandwich assay between whole live cells, V. fischeri and DNA aptamer probes. Following 9 rounds of Cell-SELEX and one of the negative-SELEX, V. fischeri Cell Aptamer (VFCA)-02 and -03 were isolated, with the former showing approximately 10-fold greater avidity (in the subnanomolar range) for the target cells when arrayed on a surface. The colorimetric response of a paper sensor based on VFCA-02 was linear in the range of 4 × 101 to 4 × 105 CFU/mL of target cell by using scanning reader. The linear regression correlation coefficient ( R2) was 0.9809. This system shows promise for use in aptamer-conjugated gold nanoparticle probes in paper strip format for in-field detection of marine bioindicating bacteria.

Proteomic profiles of Daphnia magna exposed to lead (II) acetate trihydrate and atrazine

In this study, acute toxicity tests were performed to evaluate the impacts of lead (II) acetate trihydrate and atrazine on aquatic organism using a typical freshwater flea, Daphnia magna. Besides, the proteomic profile of the treated D. magna (LC20) was investigated in the pH range from 3 to 10 using 2-dimensional gel electrophoresis method and then analyzed by the Progenesis software to explore the differentially expressed proteins (DEPs) compared to the control organisms. The results showed that there were 179 DEPs caused by these two toxic compounds. More interestingly, the identified DEPs have been found to be involved in energy metabolism, oxidative stress response, dynamic structure of cytoskeleton filaments and effected by two chemicals in opposite ways: up- and down-regulation. A significant difference of protein expression between the control and the stress-exposed D. magna which confirmed the effect of toxic chemicals has been observed. In summary, the proteomic approach as well as the detailed analysis results were proved to be useful for understanding the novel molecular mechanisms for lead or atrazine induced pathological changes. Moreover, specific DEPs can be used as novel biomarker candidates to detect these heavy metal and pesticide.