• Korean Journal of Microbiology
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• v.45 no.3
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• pp.286-290
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• 2009

The transcription of mRNA of avian influenza virus is regulated temporally during infection. Therefore, the measurement of transcript level in host cells should be performed before viral release from host cells because errors can occur in the analysis of the transcript levels if the viruses released from the infected cells re-infect cells. In this study, the timing of viral release was determined by measuring the level of viral RNA from viruses released from H9N2-infected chicken fibroblast cell line UMNSAH/DF-1 by semi-quantitative RT-PCR. The viral genomic RNA was isolated together with mouse total RNA which was added to the collected medium as carrier to monitor the viral RNA recovery and to use its GAPDH as an internal control for normalizing reverse transcription reaction as well as PCR reaction. It was found that viral release of H9N2 in the chicken fibroblast cell line UMNSAH/DF-1 took between 16 and 20 h after infection. We measured all 8 viral mRNA levels. Of the 8 transcripts, 7 species of viral mRNAs (each encoding HA, NA, PB1, PB2, NP, M, NS, respectively) except PA mRNA showed robust amplification, indicating these mRNA can be used as targets for amplification to measure transcript levels. These results altogether suggest that the method in this study can be used for screening antiviral materials against viral RNA polymerase as a therapeutic target.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.73-83
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• 2023

Purpose: This study aimed to investigate the viral load dynamics in children with underlying malignancies diagnosed with symptomatic coronavirus disease 2019 (COVID-19). Methods: This was a retrospective longitudinal cohort study of patients <19 years old with underlying hemato-oncologic malignancies that were diagnosed with their first symptomatic severe acute respiratory syndrome coronavirus 2 polymerase chain reaction (PCR)-confirmed COVID-19 infection during March 1 to August 30, 2022. Review of electronic medical records and telephone surveys were undertaken to assess the clinical presentations and transmission route of the patients. Thresholds of negligible likelihood of infectious virus was defined as E gene reverse transcription (RT)-PCR cycle threshold (Ct) value ≥25. Results: During the 6-month study period, a total of 43 children with 44 episodes of COVID-19 were included. Of the 44 episodes, the median age of the patients included was 8 years old (interquartile range [IQR], 4.9-10.5), and the most common underlying disease was acute lymphoid leukemia (n=30, 68.2%), followed by patients post-hematopoietic stem cell transplantation (n=8, 18.2%). Majority of the patients had mild COVID-19 (n=32, 72.7%), and three patients (7.0%) had severe/critical COVID-19. Furthermore, 2.3% (n=1) died of COVID-19 associated acute respiratory distress syndrome. The largest percentage of the patients showed E gene RT-PCR Ct value ≥25 between 15-21 days (n=13, 39.4%), followed by 22-28 days (n=10, 30.3%). In 15.2% (n=5), E gene RT-PCR Ct value remained <25 beyond 28 days after initial positive PCR. Refractory malignancy status (β, 67.0; 95% confidence interval, 7.0-17.0; P=0.030) was significantly associated with prolonged duration of E gene RT-PCR <25. A patient with prolonged duration of E gene RT-PCR Ct value <25 was suspected to have infectivity shown by the transmission of the virus to his mother at day 86 after his initial positive test. Conclusions: Children that acquire symptomatic COVID-19 during refractory malignancy state are at a high risk for prolonged shedding warranting PCR-based transmission precautions in this cohort of patients.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.104-114
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• 1998

Purpose : Enteroviruses are the most common cause of aseptic meningitis. The epidemics of aseptic meningitis in 1993 and 1996 were mostly caused by echovirus type 9. Identification of the causative virus of aseptic meningitis in epidemics, is very important not only for diagnosis but also for epidemiologic purpose. The purpose of this study was to identify the causative virus and investigate the relationship between aseptic meningitis, prevailed in Masan and surrounding areas in Kyoungsangnamdo in 1997, and its clinical manifestations. Methods : One hundred twenty eight cerebrospinal fluid(CSF) and 239 stool specimens were obtained from 239 patients(213 children and 26 adult patients) with aseptic meningitis were admitted to Masan Fatima Hospitals from March to October 1997. Viral isolation and serotype identification was performed by cell culture and immunofluorescent test. Enteroviruses not typed by immunofluorescent test was confirmed by reverse transcription-polymerase chain reaction(RT-PCR). Results : 1) The peak incidence was noted in June. 2) The age of 239 patients(pediatrics-213 cases, internal medicine-26 cases) that were diagnosed ranged from neonate to 35 years, the age of the patients of pediatrics ranged from neonate to 15years(mean 4.9 years), the age of the patients of internal medicine (above 16 years) ranged from 16 years to 35 years(mean 24.2 years). 3) Fifty-three(41.4%) of 128 CSF specimens were positive for enteroviruses, and 163(68.2%) of 239 stool specimens were positive for enteroviruses respectively. 4) Serotypes of 53 enteroviruses isolated from CSF were 16(30.2%) of echovirus type 30, 6(11.3%) of echovirus type 6, 1 of echovirus type 4, 4 of untyped echovirus, 1 of coxsackievirus type B5, and 24 isolates of untyped enteroviruses. Of 163 enterovirus isolated from stool were 72(44.2%) of echovirus type 30, 21(12.9%) of echovirus type 6, 1 of echovirus type 4, 17(10.4%) of undetermined subtyped echovirus, 1 of coxsackievirus type B5, 2 of A24, 3 of undetermined subtyped coxsackievirus type B, and 46 isolates of untyped enterovirus. Conclusion : There were epidemics of aseptic meningitis in the central areas of Kyoungsangnamdo from March to October 1997. The main causative organism was thought to be the echovirus type 30, and echovirus type 4, 6, coxsackievirus B5 and A24 were also thought to contribute to the epidemics.

• Journal of Life Science
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• v.25 no.10
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• pp.1115-1123
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• 2015

The purpose of this study was to investigate the potential of Nelumbo nucifera G. leaf (NNL) extract as a cosmetic additive. The electron-donating ability of the NNL extract at a concentration of 1,000 μg/ml was 67.83%. In xanthine oxidase, the inhibition effect of the NNL extract was 92.7% at the same concentration. For whitening effects, tyrosinase inhibition effect of NNL extract was 42.7% at a 1,000 μg/ml concentration. The cell toxicity of the NNL extract was examined in melanoma cells (B16F10) using a 3-[4, 5–dimethyl–thiazol–2–yl]-2, 5-diphenyl-tetrazoliumbromide (MTT) assay. The cell toxicity assay revealed that the NNL extract had a toxicity of 81.61% at a concentration of 1,000 μg/ml The microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), and tyrosinase protein expression inhibitory effect by Western blot of NNL extract were measured by a Western blot at concentrations of 25, 50, and 100 μg/ml. At a 100 μg/ml concentration of the NNL extract, the expression of the MITF, TRP-1, TRP-2, and tyrosinase protein was decreased by 69.59%, 27.74%, 67.33%, and 67.78% respectively. The MITF, TRP-1, TRP-2 and tyrosinase mRNA expression inhibitory effect were measured by reverse transcription- polymerase chain reaction (PCR) at concentrations of 25, 50, and 100 μg/ml. GAPDH was used as a positive control. At a concentration of 100 μg/ml of the NNL extract, the expression of MITF, TRP-1, TRP-2, and tyrosinase mRNA was decreased by 67.51%, 71.36%, 85.74%, and 83.64%, respectively. These findings suggest that the NNL extract has antioxidant and whitening effects and that it has great potential as a cosmetic ingredient.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.6
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• pp.483-490
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• 2001

There were many controversies in the cause and progress of tumorigenesis. Recently, studies on the mutation of genes related to the tumor have extensively been performed due to development of molecular biology. Structural and morphological changes of chromosomes, which are related to the abnormal activation of oncogenes or inactivation of tumor suppression genes, transform the normal cells into the tumor cells. p53 and Rb are well known tumor suppressor genes, while oncogenes include c-myc, bcl-2 and ras, etc. When exposed to cell damaging agents, p53 inhibits cell growth by inducing transcription of p21. Especially p73, which is homo-logy of p53, frequently deleted in melanoma, neuroblastoma, colon cancer, and breast cancer, when over produced, p73 activates the transcription of p21, bax-1 and inhibits cell growth by inducing apoptosis. For study on mRNA expression of p21 and p73, normal oral keratinocytes, and cell lines of primary and metastatic oral squamous cell carcinoma were cultured and then electrophoresis and RT-PCR(reverse transcription-polymerase chain reaction) were performed. 1. The mRNA of p21 and p73 in normal oral keratinocyte expressed lower than that of primary squamous cell carcinoma. 2. The mRNA of p21 in metastatic oral squamous carcinoma cell lines was expressed as various patterns compared with that of normal oral keratinocyte. 3. In the metastatic oral squamous cell lines, the mRNA of HN8 expressed higher than that of HN12 or HN19. 4. The mRNA of p73 in primary oral squamous cell lines expressed 4-5 times higher than that of normal keratinocyte. 5. In metastatic oral squamous cell lines, there was no significant expression of p73 mRNA compared with that of normal oral keratinocyte. From the results obtained in this study, mRNA expression of p73 in primary oral squamous cell lines was remarkable, while mRNA expression of p21 and p73 in metastatic oral squamous cell lines were statistically insignificant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1126-1131
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• 2010

The antiobesity effect of soymilks fermented with Bacillus subtilis KC-3 (KCCM 42923) from cheonggukjang was compared with other sources of B. subtilis KCCM 11316 and B. subtilis MYCO. The antiobesity effect was investigated by measuring the release of leptin, Oil red O staining, glycerol secretions and adipogenic transcription factor by reverse transcription-polymerase chain reaction (RT-PCR) in the 3T3-L1 adipocytes. Fermented soymilk with B. subtilis KC-3 (F-KC) led to decrease levels of leptin secretion and increase levels of glycerol secretion in the cells. In addition, F-KC reduced contents of Oil red O dye in the 3T3-L1 adipocytes. Also, mRNA expression levels of both SREBP-1c (sterol regulatory element-binding protein 1-c) and PPAR-$\gamma$ (peroxisome proliferator-activated receptor-$\gamma$), which are adipogenic transcription factor, in cells treated with F-KC were markedly down regulated. These results demonstrate that the Bacillus subtillis fermented soymilk (F-KC) decreased lipid content in 3T3-L1 adipocytes by inhibiting lipogenesis. All B. subtilis fermented soymilks had shown antiobesity activities, however, F-KC exhibited the strongest antiobesity effect in the 3T3-L1 adipocytes. Our study suggests that especially F-KC increased the potential of antiobesity effects.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.1-7
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• 2005

Methylophaga aminosulfidovorans SK1 (KCTC 10323 BP) can utilize trimethylamine as a sole carbon, nitrogen, and energy source. The bacterial flavin-containing monooxygenase (bFMO) gene was identified in the strain and the recombinant enzyme expressed in E. coli oxidized trimethylamine. To study the function and regulation of the bfmo, over 8,000 nucleotide sequences of the neighboring regions including the bfmo were determined. Three open reading frames proceeding to the bfmo gene encoded analogues to highly conserved nitrate/nitrite sensing two-component system regulators and a methyl accepting protein. Two small open reading frames just downstream of the bfmo gene showed no similar proteins of known functions but the sequences were conserved among other bacteria. Reverse transcription-polymerase chain reaction analysis showed that the six putative genes consisted of three transcription units. The three regulatory genes located upstream of the bfmo gene formed two separate transcription units. The bfmo and the two downstream genes were transcribed from a single promoter.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.295-299
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• 2007

The detrimental effects of gene transfection on embryo development and the molecular mechanism behind the differential expression of genes related to early embryo development were assessed in the production of transgenic cow embryos through somatic cell nuclear transfer (NT). Parthenogenetic, IVF, and transgenic NT embryos derived from ${\alpha}_1$-antitrypsin transfected ear fibroblast cells was produced. To investigate the molecular mechanism behind lower developmental competence of transgenic NT embryos, the differential mRNA expression of three genes ($IFN-{\tau}$, Oct4, Fgf4) in the 3 types of embryo (Parthenogenetic, IVF, transgenic NT) was examined. RNA was extracted from ten blastocysts derived from 3 types of embryos and reverse-transcripted for synthesis of the first cDNA. The quantification of 3 gene transcripts ($IFN-{\tau}$, Oct4, and Fgf4) was carried out in three replicate by quantitative real-time reverse transcriptase PCR. Expression level of $IFN-{\tau}$ mRNA was significantly higher in transgenic NT embryos than parthenogenetic and IVF embryos (P<0.05). However, expression level of Oct4 and Fgf4 of transgenic NT embryos was significantly lower than IVF embryos (P<0.05). Altered levels of these three mRNA transcripts may explain some of the embryonic/fetal/neonatal abnormalities observed in offspring from transgenic NT embryos.

• Journal of Life Science
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• v.19 no.3
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• pp.384-389
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• 2009

This study was carried out to elucidate the relation between expression levels of three melanin synthesis genes (Tyrosinase, Tyrosinase-related protein 1 and Dopachrome tautomerase) according to the Melanocortin-1 receptor genotypes with coat color patterns in Hanwoo cattle, Jeju black cattle and Holsteins. Using real-time semiquantitative reverse transcription-PCR assay (RT-PCR), the expression levels of these three genes were analyzed in skin tissues from four representative coat colored areas: yellowish-brown from MC1R e/e Hanwoo, wild type black from $E^+/E^+$ Jeju black cattle (JBC), and dominant black and white pied regions from $E^D/E^D$ Holstein. The TYR, TYRP1 and DCT genes showed higher expression levels of 4.5, 2.3 and 2.5 times higher in the black skin area of Holsteins than those of from JBC, respectively (p<0.001). In addition, the expression levels of these three genes from JBC were significantly higher than those from Hanwoo cattle (p<0.001). These results show that coat color phenotypes in Hanwoo cattle, JBC and Holsteins is directly correlated with TRY, TYRP1 and DCT transcription levels, which probably reflected involvement with MC1R genotypes; e/e in Hanwoo, $E^+/E^+$ in JBC and $E^D/E^D$ in Holsteins. Consequently, this study suggested that the status of MC1R protein may not only induce the transcription activities of a series of TYR and its related genes responsible for melanin synthesis, but also determine the levels of total melanin contents in bovine skin.

• Research in Plant Disease
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• v.18 no.4
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• pp.391-395
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• 2012

To investigate the occurrence of viruses in peach, leaf samples were collected from peach trees in commercial orchard of six areas in Korea. Reverse transcription polymerase chain reaction (RT-PCR) was used to identify the presence of the following stone fruit viruses: Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV) and Plum pox virus (PPV). About 65.0% of the 515 samples were infected with ACLSV and PNRSV. Virus-like symptoms showing mosaic on leaves was observed in ACLSV infected peach trees. However, PNRSV infected peach trees showed no symptoms. These viral DNAs by sequence analysis were confirmed 4 ACLSV isolates and 3 PNRSV isolates. The Korean peach isolates of ACLSV and PNRSV showed 70-99% and 88-99% amino acid sequence identities, respectively, with those reported previously and their amino acid sequence identities with each other were approximately 95% and 88%, respectively. Phylogenetic analysis indicated that the Korean ACLSV isolates belong to the A group of ACLSV. The Korean PNRSV isolates reported in this study were grouped into I (PV32), II (PV96) and III (PE5) groups.