• Journal of Environmental Analysis, Health and Toxicology
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• v.21 no.4
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• pp.264-280
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• 2018

In this study, volatile organic compounds (VOCs) were measured using a proton transfer reaction-time of flight-mass spectrometer (PTR-ToF-MS) at the Seoul Metropolitan Area Intensive Monitoring Station (SIMS) in Korea during the summer season of 2018. The results revealed that oxygenated VOCs (OVOCs) contributed a large fraction (83.6%) of the total VOCs, with methanol being the most abundant constituent (38.6%). The VOCs measured at SIMS were strongly influenced by local conditions. Non-volatile organic compounds (NVOCs), such as pinene, increased due to northeasterly wind direction in the morning, and OVOCs and anthropogenic VOCS (AVOCs) increased with northwesterly wind direction during the daytime. This was the result of the eastward location of Bukhansan National Park and the westward location of urban area from the SIMS location. The VOCs included abundant oxidized forms of VOCs, which can affect the generation of fine dust through various response pathways in the atmosphere. The real-time measurement technique using PTR-ToF-MS suggested in this study is expected to contribute to an improved scientific understanding of high-concentration fine dust events because the high temporal resolution makes it possible to analyze the variations of VOCs reflected in dynamic events.

• Journal of Microbiology and Biotechnology
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• v.34 no.5
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• pp.1146-1153
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• 2024

The increasing economic losses associated with growth retardation caused by Enterocytozoon hepatopenaei (EHP), a microsporidian parasite infecting penaeid shrimp, require effective monitoring. The internal transcribed spacer (ITS)-1 region, the non-coding region of ribosomal clusters between 18S and 5.8S rRNA genes, is widely used in phylogenetic studies due to its high variability. In this study, the ITS-1 region sequence (~600-bp) of EHP was first identified, and primers for a polymerase chain reaction (PCR) assay targeting that sequence were designed. A newly developed nested-PCR method successfully detected the EHP in various shrimp (Penaeus vannamei and P. monodon) and related samples, including water and feces collected from Indonesia, Thailand, South Korea, India, and Malaysia. The primers did not cross-react with other hosts and pathogens, and this PCR assay is more sensitive than existing PCR detection methods targeting the small subunit ribosomal RNA (SSU rRNA) and spore wall protein (SWP) genes. Phylogenetic analysis based on the ITS-1 sequences indicated that the Indonesian strain was distinct (86.2% nucleotide sequence identity) from other strains collected from Thailand and South Korea, and also showed the internal diversity among Thailand (N = 7, divided into four branches) and South Korean (N = 5, divided into two branches) samples. The results revealed the ability of the ITS-1 region to determine the genetic diversity of EHP from different geographical origins.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.3
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• pp.189-197
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• 2024

From March to November 2021, a study conducted in Jeju used the dry ice trap method to collect 17,855 ticks across six regions, examining their distribution and potential as disease vectors. The ticks were identified and categorized by species and growth stage. In addition, the study focused on Babesia, a disease transmitted by hard ticks. Of 17,641 ticks from which DNA had been extracted, 581 pools underwent polymerase chain reaction testing. Of these, 43 pools tested positive for Babesia, with the highest positivity found in Western Seogwipo (23 pools, 53.5%), followed by eastern Seogwipo and central Jeju. The peak times for positive results were April and July. This study highlights an increased risk of tick bites linked to the rising number of abandoned pets in Jeju, necessitating ongoing environmental management and monitoring. These findings provide fundamental data for formulating strategies to prevent and manage tick-borne diseases in Jeju. This involves reducing the disease incidence through targeted preventive measures and detailed epidemiological research. These results underscore the necessity for continued vigilance and proactive intervention to address the health challenges ticks pose in the region.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.194-201
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• 2016

Purpose: Monitoring pneumococcal carriage rates is important. We developed and evaluated the accuracy of a real-time reverse transcription polymerase chain reaction (RT-PCR) protocol for the detection of Streptococcus pneumoniae. Methods: In October 2014, 157 nasopharyngeal aspirates were collected from patients aged <18 years admitted to Chung-Ang University Hospital. We developed and evaluated a real-time PCR method for detecting S. pneumoniae by comparing culture findings with the results of the real-time PCR using genomic DNA (gDNA). Of 157 samples, 20 specimens were analyzed in order to compare the results of cultures, real-time PCR, and real-time RT-PCR. Results: The concordance rate between culture findings and the results of real-time PCR was 0.922 (P<0.01, Fisher exact test). The 133 culture-negative samples were confirmed to be negative for S. pneumoniae using real-time PCR. Of the remaining 24 culture-positive samples, 21 were identified as S. pneumonia -positive using real-time PCR. The results of real-time RT-PCR and real-time PCR from 20 specimens were consistent with culture findings for all S. pneumoniae -positive samples except one. Culture and real-time RT-PCR required 26.5 and 4.5 hours to perform, respectively. Conclusions: This study established a real-time RT-PCR method for the detection of pneumococcal carriage in the nasopharynx. Real-time RT-PCR is an accurate, convenient, and time-saving method; therefore, it may be useful for collecting epidemiologic data regarding pneumococcal carriage in children.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.483-488
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• 2008

Foodborne pathogenic bacteria in various food samples in Korea were monitored and the obtained data was statistically analyzed. A total of 1,240 food samples including 280 sashimi, 244 processed frozen products, 258 kimbab (cooked rice wrapped with seaweed), 337 soybean pastes were obtained from 7 cities including Seoul in Korea. Microorganisms tested were Bacillus cereus, Salmonella spp., Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Vibrio parahaemolyticus, Yersinia enterocolitica, Listeria monocytogenes, Campylobacter jejuni, and Clostridium perfringens. The contaminated microorganisms in food samples were comprised of 10.55% B. cereus, 2.7% S. aureus, 2.0% V. parahaemolyticus, 0.8% C. perfringens, 0.2% Y. enterocolitica, and 0.1% of L. monocytogenes, respectively. Salmonella spp., C. jejuni, and E. coli O157:H7 were not detected in any of the food samples. Particularly, B. cereus that harbors the enterotoxin gene was detected in various foods and regions in Korea, therefore it should be a given special consideration not to allow the hazardous level of contamination.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.132-133
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• 2003

The marine dinoflagellate genus Alexandrium comprise PSP producing A. acatenella, A. angustitabuzatum, A. catenella, A. fundyense, A. minutum, A. ostenfezdii, A. tamiyavanichii and A. tamarense. In monitoring toxic Alexandrium, rapid and exact species identification is one of the significant prerequisite work, however we have suffered confusion of species definition in Alexandrium. To surmount this problem, we chose DNA probing, which has long been used as an alternative for conventional identification methods, primarily relying on morphological approaches using microscope in microbial field. Oligonucleotide DNA probes targeting rRNA or rDNA have been commonly used in diverse studies to detect and enumerate cells concerned as a culture-indetendent powerful tool. Despite of the massive literature on the HAB species containing Alexandrium, application of DNA probing for species identification and detection has been limited to a few documents. DNA probes of toxic A. tamarense, A. catenella and A. tamiyavanichii, and non-toxic A. affine, A. fraterculus, A. insuetum and A. pseudogonyaulax were designed from LSU rDNA D1-D2, and applied to whole cell-FISH. Each DNA probes reacted only the targeted Alexandrium cells with very high species-specificity within Alexandrium. The probes could detect each targeted cells obtained from the natural sea water samples without cross-reactivity. Labeling intensity varied in the growth stage, this showed that the contents of probe-targeted cellular rRNA decreased with reduced growth rate. Double probe TAMID2S1 achieved approximately two times higher fluorescent intensity than that with single probe TAMID2. This double probe did not cross-react with any kinds of microorganisms in the natural sea waters. Therefore we can say that in whole-cell FISH procedure this double DNA probe successfully labeled targeted A. tamiyavanichii without cross-reaction with congeners and diverse natural bio-communities.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.9
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• pp.4033-4037
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• 2014

Emerging evidence has shown associations of microRNA-205 (miR-205) with crucial cell processes such as the epithelial-mesenchymal transition (EMT) and aberrant expression with tumorigenesis in many types of human malignancy. This prospective study characterized the contribution of miR-205 to the colorectal cancer (CRC) tumorigenesis. The real-time reverse transcription-polymerase chain reaction was used to examine miR-205 levels prospectively in 36 pairs of samples of CRC tissue and adjacent noncancerous tissue (>2 cm from cancer tissue). In addition, the relationship between miR-205 levels and clinicopathological features was explored. The capability of miR-205 to function as a tumor marker was also examined. miR-205 expression levels did not show significant changes overall. However, miR-205 was significantly downregulated in a group of CRC samples compared with matched noncancerous tissue samples. Moreover, decreased miR-205 correlated significantly with lymphatic metastasis. A receiver operating characteristic (ROC) curve also showed an optimum cut off point of $1.4{\times}10^{-3}$ to distinguish lymphatic metastatic CRCs from non-metastatic CRCs. Interestingly we found lymphatic metastasis in almost 80% of the depressed samples. This study suggested that miR-205 could be reduced in the majority of metastatic CRCs and the risk of CRC metastasis may be predicted by monitoring miR-205 in patient samples collected at the time of the initial diagnosis. Therefore, targeting miR-205 and its potential environmental activators might be a promising therapeutic option to prevent malignant progression toward metastasis.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.147-153
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• 2007

A simple, selective and highly sensitive flow injection catalytic method was presented for determination of ruthenium based on its catalytic effect on the oxidation of pyronin B by periodate in pH=1.0. The reaction rate is controlled specrophotometricaly by monitoring the dye absorbance at 555 nm. The optimized conditions make it possible to determine ruthenium in the ranges of 0.1-10.0 ng/mL (r2=0.9982) and 10.0-50.0 ng/mL (r2=0.9934) with a detection limit of 0.04 ng/mL and a sample rate of 30±5 samples/h. Relative standard deviation for the results of five replicate measurements does not exceed 1.44%. The proposed method has been successfully applied for quantitation of ultra trace amounts of ruthenium in some environmental and biological samples.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2760-2764
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• 2013

Geniposide is a biologically active ingredient of gardenia fruit. A liquid chromatography-tandem mass spectrometric method was developed and validated for the determination of geniposide in rat plasma. The plasma samples were pretreated by solid-phase extraction and introduced into a BDS Hypersil $C_{18}$ column ($50{\times}2.1mm$, $5{\mu}m$) for chromatographic separation. The mobile phase consisted of 0.1% formic acid and 0.1% formic acid in acetonitrile, and gradient elution was performed at a flow rate of 0.25 mL/min. For mass spectrometric detection, multiple reaction monitoring was performed via an electrospray ionization source in positive mode. The calibration curve for geniposide was linear ($r^2=0.997$) in the concentration range of $0.005-1{\mu}g/mL$. The intra- and inter-day accuracies and precisions fulfilled the required criteria (${\pm}15%$). The developed method was subsequently used for pharmacokinetic analysis of geniposide after oral administration to rats at a dose of 50 mg/kg. The mean maximum plasma concentration of geniposide was $0.68{\pm}0.29{\mu}g/mL$ at $0.44{\pm}0.13h$, and the mean area under the plasma concentration versus time curve was $1.46{\mu}g{\cdot}h/mL$.

• Journal of mucopolysaccharidosis and rare diseases
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• v.3 no.1
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• pp.20-27
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• 2017

Purpose: Mucopolysaccharidosis IV (MPS IV) is a disease characterized by deficient activity of N-acetylgalactosamine-6-sulfatase (GALNS) causing excessive lysosomal storage of keratan sulfate (KS). The identification of the relevant disaccharide units of KS after keratanase II digestion followed by liquid chromatography/tandem mass spectrometry detection (LC-MS/MS) is validated and applicable for the preliminary diagnosis of MPS IV. Methods: A total of 67 urine samples were collected and analyzed from 11 MPS IV patients comprising 10 MPS IVA and one MPS IVB patients, and 56 normal controls. Urinary glycosaminoglycan was first precipitated by the Alcian blue method followed by a digestion of keratanase II. The protonated species of the digested disaccharide products were detected by using multiple reaction monitoring experiment. Results: One particular disaccharide of KS was selected. The transition mass-to-charge (m/z) of the parent ion and its daughter ion after collision was $462.0{\rightarrow}97.0$, whereas the chondrosine used as an internal standard in this assay was m/z $353.9{\rightarrow}73.0$. The results corresponded well with the two-dimensional electrophoresis method. The quantities of urinary KS were significantly raised in confirmed MPS IV patients when comparing with those of normal controls ($170.2{\pm}81.1$ vs. $4.06{\pm}1.92{\mu}g/mL$). Conclusion: The LC-MS/MS method for MPS IVA determination is specific, sensitive, validated, and applicable for urinary KS quantification. This method can be used not only as a first-line biochemistry examination of MPS IVA, but also as an outcome survey after enzyme replacement therapy.