• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.460-470
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• 2017

Mussels are major fouling organisms causing serious technical and economic problems. In this study, antifouling activity towards mussel was found in three compounds isolated from a marine bacterium associated with the sea anemone Haliplanella sp. This bacterial strain, called PE2, was identified as Vibrio alginolyticus using morphology, biochemical tests, and phylogenetic analysis based on sequences of 16S rRNA and four housekeeping genes (rpoD, gyrB, rctB, and toxR). Three small-molecule compounds (indole, 3-formylindole, and cyclo (Pro-Leu)) were purified from the ethyl acetate extract of V. alginolyticus PE2 using column chromatography techniques. They all significantly inhibited byssal thread production of the green mussel Perna viridis, with $EC_{50}$ values of $24.45{\mu}g/ml$ for indole, $50.07{\mu}g/ml$ for 3-formylindole, and $49.24{\mu}g/ml$ for cyclo (Pro-Leu). Previous research on the antifouling activity of metabolites from marine bacteria towards mussels is scarce. Indole, 3-formylindole and cyclo (Pro-Leu) also exhibited antifouling activity against settlement of the barnacle Balanus albicostatus ($EC_{50}$ values of 8.84, 0.43, and $11.35{\mu}g/ml$, respectively) and the marine bacterium Pseudomonas sp. ($EC_{50}$ values of 42.68, 69.68, and $39.05{\mu}g/ml$, respectively). These results suggested that the three compounds are potentially useful for environmentally friendly mussel control and/or the development of new antifouling additives that are effective against several biofoulers.

• Journal of fish pathology
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• v.36 no.2
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• pp.277-286
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• 2023

Korean rockfish, Sebastes schlegelii, is a representative bony fish that belongs to the family Scorpaenidae and the order Scorpaeniformes. It has high ecological and economic value and is widely cultivated in many East Asian countries, including South Korea, Japan and China. One of streptococci, Streptococcus iniae, is Gram-positive cocci with a negative reaction for catalase and oxidase. The Korean rockfish shows clinical signs when infected with S. iniae, such as body darkening, bleeding, enlarged kidneys, blurred eyes, abdominal distension, etc., ultimately leading to death. The Korean rockfish causes significant economic losses every year in South Korea due to streptococcosis. In this study, we identified bacteria from the fish using polymerase chain reaction and conducted analyses of hemolytic activity and biochemical tests using API 20 STREP and API ZYM systems. Results of confirming the hemolytic activity (n=4) observed in alpha-type hemolysis (25%), beta-type hemol- ysis (50%), and gamma-type hemolysis (25%) of isolates. The biochemical test results exhibited sig- nificant variation among S. iniae. Additionally, we performed intraperitoneal injection with S. iniae in the fish and analyzed the phylogenetic tree using housekeeping genes of S. iniae, including cpsD, arcC, glnA, groEL, gyrB, mutS, pheT, prkC, rpoB, and tkt, via multilocus sequence typing (MLST). The lethal dose (LD₅₀) showed strong pathogenicity, such as 3.34 × 10 colony-forming unit (CFU)/ml for 23FBStr0601 strain and 7.16 × 10 CFU/ml for 23FBStr0602 strain. 23FBStr0603 strain showed relatively low pathogenicity at 1.73 × 10⁵ CFU/ml. The strains 23FBStr0601 and 23FBStr0602, which showed strong pathogenicity, clustered into one monophyletic group. The 23FBStr0603 strain showed weak pathogenicity and formed a monophyletic group with KCTC 3657.

• IMMUNE NETWORK
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• v.3 no.3
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• pp.235-241
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• 2003

Background: The protective immunity against tuberculosis (TB) involves both CD4+ T cells and CD8+ T cells. In our previous study, we defined four Mycobacterium tuberculosis derived peptide epitopes specific for HLA-$A^*0201$ restricted CD8+ T cells ($ThyA_{30-38}$, $RpoB_{127-135}$, $85B_{15-23}$, $PstA1_{75-83}$). In this study, we investigated the immune responses induced by these peptide specific CD8+ T cells in latently and chronically infected people with TB. Methods: We characterized these peptide specific CD8+ T cell population present in PBMC of both TB patients and PPD+healthy people using IFN-${\gamma}$elispot assay, intracellular staining and HLA-A2 dimer staining. Results: The frequency of peptide specific CD8+ T cell was in the range of 1 to 25 in $1.7{\times}10^5$ PBMC based on ex vivo IFN-${\gamma}$ elispot assay, demonstrating that these peptide specific CD8+ T cell responses are induced in both TB patients and PPD+ people. Short term cell lines (STCL) specific for these peptides proliferated in vitro and secreted IFN-${\gamma}$ upon antigenic stimulation in PPD+ donors. Lastly, HLA-$A^*0201$ dimer assays indicated that $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors is heterogeneous since approximately 25~33% of $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors produced IFN-${\gamma}$ upon peptide stimulation. Conclusion: Our results suggest that MHC class I restricted CD8+ T cell mediated immune responses to M. tuberculosis infection are induced in both TB patients and PPD + people; however, the CD8+ T cell population is functionally heterogeneous.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.83-89
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• 2015

Although Mycobacterium tuberculosis complex strains remain responsible for the majority of diseases caused by mycobacterial infections worldwide, the increase in HIV (human immuno deficiency virus) infections has allowed for the emergence of other non-tuberculous mycobacteria as clinically significant pathogens. M. tuberculosis was detected by two-tube nested polymerase chain reaction (PCR) and non-tuberculous mycobacteria was detected by PCR-restriction fragment length polymorphism (RFLP) with Msp I. Result of niacin test is equal to result of two-tube nested PCR after culture for M. tuberculosis. In this study, acid fast bacilli stain (AFB. stain) >2+ case, Detection of Mycobacteria is similar to result before culture and after culture. AFB. stain <1+ case, result of mycobacteria is distinguished. Conclusionly, these results suggest that identification of mycobacteria must go side by side both culture and PCR for more fast and accuracy.

• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.606-612
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• 2005

Background : It has been reported that nontuberculosis mycobacterium(NTM) isolates account for approximately 10% of patients with a positive Acid-Fast Bacilli(AFB) smear. Therefore, it is necessary to consider NTM pulmonary disease when such a positive test is encountered. The aim of this study was to evaluate the etiologies and clinical characteristics of patients with NTM pulmonary disease who had been treated at a national tuberculosis hospital. Methods : The NTM isolates were recovered from the sputum or bronchial washing specimens submitted to a clinical laboratory of National Masan TB Hospital from August 2002 to July 2003. All samples were identified using a polymerase chain reaction-restriction fragment length polymorphism analysis method, which amplifies the rpoB gene. The patients were diagnosed with NTM disease according to the American Thoracic Society diagnostic criteria. Results : One hundred NTM isolates were recovered from 57 patients. Of the 100 isolates, M. avium complex(MAC) was the most common species, which was found 55%(n=55) of patients, followed by M. abscessus(n=25), and M. fortuitum( n=9). 26(45.6%) patients had NTM disease. Twenty-six (45.6%) patients had NTM disease according to The American Thoracic Society classification. The main organisms involved in NTM disease were MAC(n=19, 73.1%) and M. abscessus(n=5, 19.2%). The pathogenic potential was 67.9% in M. intracellulare and 41.7% in M. abscessus. The predictive factors related to NTM disease were a positive sputum smear (OR 6.4, p=0.02) and the isolation of either MAC or M. abscessus(OR 6.9, p=0.007). Fifteen patients(57.7%) were cured. There were no significant factors associated with the treatment success. Conclusion : There was a relatively high proportion of NTM disease in NTM isolates and the common species were MAC and M. abscessus. The predictive factors for NTM disease were a positive sputum smear and the isolation of either MAC or M. abscessus.