• Korean Journal of Weed Science
• /
• v.9 no.1
• /
• pp.16-27
• /
• 1989

The six barnyardgrass [Echinochloa oryzicola (vasing.) Vasing.] and seventeen barnyardgrass [Echinochloa crus-gadli (L.) Beauv.] accessions, which were collected national widely in 1986 and selected two times through 1987. To study different growth response due to herbicide, pyrazolate, bifenox, quinclorac, the experiment was conducted with herbicide agar culture without nutrients, 1. Albinistic discoloration due to pyrazolate was more sensitive in E, crus-galli than E. oryzicola and among barnyardgrass accessions, Kumi, Ichon-A, Ichon-B, Boun-B and Kwangju-B were rather susceptible than Gyongju, Ansong, Boun-A, Jongju-A and Kwangju-A. 2. Twisting and growth retardation due to bifenox was less sensitive in E. oryzicola with less intra-specific variations than in E. crus-galli. Among E. crus-galli accessions, Boun-B, Ansong, Ichon-A, Ichon-B, Wonju and Kwangju-B were particulary susceptible, and Jinyang, Jongju-B, Jongju-A, Daejon, Kurye and Kwangju-A were tolerant as much as E. oryzicola. 3. Growth retardation and withering to dead due to quinclorac was more sensitive in E. oryzicola with less intra-specific variations than in E. crus-galli. Among accessions of E. curs-galli, Boun-A, Iri, Jongju-A, Jongju-B, Kwangju-A and Kwangju-B were rather similar suseptible to E, oryzicola than kimhae, Gyongju, Kumi, Wonju, Ichon-A, Ichon-B and Ansong. 4. Most accession of E. oryzicola was tolerant to both pyrazolate and bifenox, while susceptible to quinclorac. Among other accessions of E. crus-galli, Kurye, Kimhae, and Daejon were tolerant to all experimented herbicides, and Iri, Jongju-A, Jongju-B, and Kwangju-A were only tolerant to both pyrazolate and bifenox, while Kumi, Wonju, Ichon-A, Ichon-B, Boun-B and Kwangju-B were only tolerant to quinclorac.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.1
• /
• pp.94-105
• /
• 2001

Background : Examining the biological susceptibility of Mycobacterium tuberculosis to pyrazinamide (PZA) in vitro is very difficult as PZA is inactive under normal culture conditions. The biological susceptibility test, an enzyme assay for Pzase activity, and a genetic test for pncA gene mutations, were performed in order to predict PZA resistance. Methods : 28 cultured clinical isolates of Mycobacterium tuberculosis were tested. The biological susceptibility was performed by the absolute concentration method using Lowenstein-Jensen media. The PZase activity was tested by means of Wayne's method. A 710-bp region includes the entire open reading frame of pncA was amplified and sequenced. Results : All six strains with positive PZase activity exhibited no pncA mutations with one strain showing a false resistance in the biological susceptibility test. Among the 22 strains with no PZase activity, 21 exhibited showed pncA mutations. In the biological susceptibility test, 20 strains were resistant, and one was susceptible, and the other flied to test. The mutation types varied with ten missense, one silent and one nonsense mutation 1 slipped-strand mispairing, and 6 frameshift mutations. Three strains had an adenine to guanine mutation at position -11 upstream of the start codon. Conclusion : The mutation at the pncA promotor region is frequent at -11 upstream position. Automatic sequencing of pncA is a useful tool for rapid and accurate detection of PZA resistant M. tuberculosis, and for demonstrating the epidemiological relatedness of the PZA resistant M. tuberculosis strains.

• Journal of Veterinary Clinics
• /
• v.32 no.2
• /
• pp.191-195
• /
• 2015

A 7-year-old castrated male Korean Shorthair cat was referred with lethargy and anorexia. Laboratory examination revealed moderate degenerative changes of peripheral neutrophils on blood smear examination and decreased levels of free and total thyroxine ($T_4$) as well as bacterial growth on blood culture. Molecular analyses of the 16S ribosomal RNA gene and heat shock protein 60 gene confirmed the bacterium as Enterobacter cloacae. A minimal inhibitory concentration test showed multidrug resistance of the bacterium against 16 antibiotics. Polymerase chain reaction (PCR) and subsequent sequencing specifically for $bla_{TEM}$, $bla_{SHV}$, $bla_{CTX-M}$, and plasmid-mediated ampC genes revealed positive results to $bla_{TEM-1}$, $bla_{CTX-M-15}$, and plasmid-mediated $bla_{ACT-1}$ genes, indicating that the isolated bacterium contains plasmids containing genes encoding extended-spectrum beta-lactamase and plasmid-mediated ampC beta-lactamase. After 1 month of treatment with antibiotics and levothyroxine, the cat's condition improved; both the thyroid function test and the blood culture showed no abnormalities. This is the first report of community-acquired multidrug-resistant E. cloacae-induced euthyroid sick syndrome in a cat. By the prompt diagnostic procedures and properly selected antibiotic therapy, the cat was recovered from the multidrug-resistant bacterium-induced septicaemia.

• Journal of the Korean Chemical Society
• /
• v.57 no.1
• /
• pp.81-87
• /
• 2013

Staphylococcus aureus is the most important pathogen in nosocomial infections, including bloodstream infections. Prompt identification of S. aureus from blood cultures and detection of methicillin resistance are essential in cases of suspected sepsis. We have studied a new method for the sequence-specific visual detection of minute amounts of nucleic acids using intercalating reaction by addition of SYBR Green to amplicons of LAMP, and it's a unique gene amplification method in which DNA can be isothermally amplified using only one enzyme. Staphylococcus-LAMP, which targets the spa gene, encoding S.aureus-specific protein A, and the mecA gene, encoding penicillin-binding protein-2' for methicillin resistance, detected MRSA and MRSE. In this study, by using LAMP assay, I detected for Staphylococcus aureus and Staphylococcus epidermidis concentration in the clinical sample. The detection of Staphylococcus aureus and Staphylococcus epidermidis was tested by using serial 10-fold dilutions standard solution. I have accurate detected the limit of detection, sensitity, specificity and reproducibility of the assay. The Bio-chip based LAMP assay allowed easy, rapid, accurate and sensitive detection of infection with Staphylococcus and especially applicable in a resource-limited situation.

• Journal of fish pathology
• /
• v.20 no.3
• /
• pp.221-227
• /
• 2007

In this study, one hundred strains of bacterial flora were isolated from the intestine of cultured and wild black rockfish Sebastes inermis collected in Yeosu and examined for drug resistance to 9 antibiotics. From cultrued fish, the isolated bacteria were Photobacterium group (26 strains) and Acinetobacter group (18 strains) of Gram-negative, and unidentified marine sediment bacterium (6 strains) of Gram-positive. From wild fish, Photobacterium group (18 strains), Acinetobacter group (12 strains) and Shewanella group (5 strains) of Gram-negative and Bacillus group (8 strains), Staphylococcus group (4 strains), and unidentified marine sediment bacterium (3 strains) of Gram-positive. Intestine flora of wild black rockfish was more diverse than that of one cultured. The drugs tested were tetracyclines (oxytetracycline), aminoglycosides (gentamicin), macrorides (erythromycin) and quinolones (flumequine, oxolinic acid, norfloxacin, ofloxacin, enrofloxacin and ciprofloxacin). Sensitivity to all seven antibiotics except oxytetracycline and oxolinic acid was higher in bacteria from wild fish than from cultured ones, although wild isolates were more resistant than control strain Escherichia coli ATCC9637. This suggests that use of antibiotics in the fish farm might have some resistance in intestinal flora of wild fish.

• Tuberculosis and Respiratory Diseases
• /
• v.60 no.2
• /
• pp.180-186
• /
• 2006

Background : Para-aminosalicylic acid(PAS) is a 2nd-line drug that can cause severe adverse reactions leading to poor patient compliance. This study evaluated the relapse rate according to the discontinuance of PAS at a certain point after bacteriological conversion during the course of chemotherapy for multidrug-resistant tuberculosis(MDR-TB). Methods : 42 out of 452 MDR-TB patients were enrolled in this study. All subjects were receiving chemotherapy including PAS at National Masan TB Hospital between Jan. 1, 2000 and Dec. 31, 2001. The relapse rate was evaluated after the discontinuance of PAS from their initial regimen as a result of the severe adverse reactions at a certain point after the bacteriological conversion during the course of chemotherapy for MDR-TB. Results : The male to female ratio was 2.5:1, and the mean age was 47.2 years old. The average number of past histories, used drugs and resistant drugs was 1.2, 3.9 and 4.3. The mean number of sensitive drugs included in the inirial regimen was 3.9. The mean time for bacteriological conversion and discontinuance of the PAS was 2.3 months after initiating treatment and 6 months after bacteriological conversion, respectively. There was no relapse after discontinuing PAS during a mean follow up period of 31.6 months. Conclusion : PAS may be discontinued in the cases of serious gastrointestinal problems approximately 6 months after bacteriological conversion without concern about relapse.

• Tuberculosis and Respiratory Diseases
• /
• v.63 no.5
• /
• pp.417-422
• /
• 2007

Background: It is not known with certainty whether patients with persistently positive sputum smear results who have also had negative sputum culture results require prolongation of treatment for tuberculosis in order to avoid an increased risk of eventual relapse. The purpose of the present study was to retrospectively describe the treatment characteristics and evaluate the appropriate duration of treatment in these patients. Methods: Sixty of 69 patients with sputum smear positive and culture negative tests at 5 months after first line anti-tuberculous chemotherapy from 2002 to 2003 were retrospectively analyzed. Exclusion criteria included incomplete treatment or resistance to rifampicin or two additional antibiotics, as determined by a drug susceptibility test (DST). Results: Smear conversion of the study subjects was observed after $8.3{\pm}2.3$ months treatment, and the patients were culture negative after $2.0{\pm}0.8$ months. The relapse rates of the study subjects were 3.8, 10.0, and 25.8% after 1, 2, and 5 years of anti-tuberculosis chemotherapy, respectively. The relapse rates were not significantly affected by a series of risk factors such as age, sex, presence of diabetes, a sputum culture examination after 2 months treatment, previous treatment history, chest radiograph, and duration of the treatment (P>0.05). Conclusion: Regimen change is not required for patients with persistent smear positive but culture negative tests in the fifth month for first line antituberculous treatment. However, a further study will be needed to clarify the high relapse rate in this specific group of patients.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.3
• /
• pp.334-342
• /
• 2001

Background : RpoB gene mutations have been found in about 96-98% of rifampicin (RMP)-resistant Mycobacterium tuberculosis. Recent reports confirm that the in laboratory settings a rpoB gene mutation can be used as a surrogate marker for multi-drug resistant tuberculosis. However, its usefulness in clinical applications has not been evaluated. This study was performed to confirm whether mutation analysis of the rpoB gene of M. tuberculosis is useful in clinical settings. Methods : The medical records of 33 patients in whom rpoB gene analysis was conducted using an INNOLiPA Rif. TB assay (LiPA) from June, 1998, to July, 2000, at the Asan Medical Center were retrospectively reviewed in 33 patients. The clinical characteristics in addition to the drug susceptibility and LiPA results were analyzed. The drug susceptibility test was considered as a gold standard method for M. tuberculosis susceptibility and these results were compared with those of the rpoB gene study and sequencing analysis. Sequencing analysis of the rpoB gene was done in cases where there was a discrepancy between the results of the drug susceptibility an d rpoB gene study. Results : The mean age and sex ratio was $42{\pm}18$, and 24:9 (M:F), respectively. There were 19 RMP susceptible (58%) and 14 RMP-resistant cases (42%) according to the rpoB gene study. The mean time from the request to reporting the results of the rpoB gene study was $5.2{\pm}2.6$ days. The mean gap from reporting the rpoB gene study to reporting the susceptibility was $56{\pm}35$ days. Twenty-eight cases (85%) showed identical results compared with the drug susceptibility results, whereas five cases (15%) showed contradictory results. When compared with the sequencing analysis, of the five cases that showed contradictory results, two had LiP A analysis errors and the remaining three were identical to the sequencing results. The rpoB gene study was of assistance in choosing the appropriate drugs in 28 cases (85%). Conclusions : An rpoB gene study using an LiP A assay was useful in rapidly diagnosing RMP-resistant tuberculosis, which enabled a proper choice of the appropriate drugs in clinical practices. However, an LiPA assay always should be performed in conjunction with microscopy, culture, and susceptibility tests.

• Radiation Oncology Journal
• /
• v.18 no.1
• /
• pp.51-58
• /
• 2000

Purpose :The effect of PTK inhibitors (herbimycin A and genistein) on the induction of radiation-induced apoptosis in Ph-positive KS62 leukemia cell line was investigated. Materials and Methods :K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. For 6 MV X-ray irradiation and drug treatment, cultures were initiated at 2×106 cells/mL. The cells were irradiated with 10 Gy. Stock solutions of herbimycin A and genistein were prepared in dimethyl sulphoxide (DMSO). After incubation at 37$^{\circ}C$ for 0$\~$48 h, the extent of apoptosis was determined using agarose gel electrophoresis and TUNEL assay. The progression of cells through the cell cycle after irradiation and drug treatment was also determined with flow cytometry. Western blot analysis was used to monitor bel-2, bel-X$_{L}$ and bax protein levels. Results :Treatment with 10 Gy X-irradiation did not result in the induction of apoptosis. The HMA alone (500 nM) also failed to induce apoptosis. By contrast, incubation of K562 cells with HMA after irradiation resulted in a substantial induction of nuclear condensation and fragmentation by agarose gel electro-phoresis and TUNEL assay. Genistein failed to enhance the ability of X-irradiation to induce DNA fragmentation. Enhancement of apoptosis by HMA was not attributable to downregulation of the bel-2 or bel-X$_{L}$ anti-apoptotic proteins. When the cells were irradiated and maintained with HMA, the percentage of cells in G2/M phase decreased to 30$\~$40$\%$ at 48 h. On the other hand, cells exposed to 10 Gy X-irradiation alone or maintained with genistein did not show marked cell cycle redistribution. Conclusion : We have shown that nanomolar concentrations of the PTK inhibitor HMA synergize with X-irradiation in inducing the apoptosis in Ph (+) K562 leukemia cell line. While, genistein, a PTK inhibitor which is not selective for p210$^{bcr/abl}$ failed to enhance the radiation induced apoptosis in KS62 cells. It is unlikely that the ability of HMA to enhance apoptosis in K562 cells is attributable to bel-2 family. It is plausible that the relationship between cell cycle delays and cell death is essential for drug development based on molecular targeting designed to modify radiation-induced apoptosis.

• Journal of Life Science
• /
• v.26 no.7
• /
• pp.835-846
• /
• 2016

Chemo-resistance is the biggest issue of effective cancer therapy. ABCG2 is highly correlated with multi-drug resistance, and represent a typical phenotype of multiple cancer stem-like cells. Accumulating evidence recently reported that oncolytic viruses represent a new strategy for multiple aggressive cancers and drug resistant cancers including cancer stem cell-like cells and ABCG2 expressing cells. In this study, we generated an evolutionally engineered vaccinia virus, SLJ-496, for drug-resistant cancer therapy. We first showed that SLJ-496 treatment enhanced tumor affinity using cytopathic effect assay, plaque assay, as well as cell viability assay. Next, we clearly demonstrated that in vitro SLJ-496 treatment represents significant cytotoxic effect in multiple cancers including colorectal cancer cells (HT-29, HCT-116, HCT-8), gastric cancer cells (AGS, NCI-N87, MKN-28), Hepatocellular carcinoma cells (SNU-449, SNU-423, SNU-475, HepG2), as well as mesothelioma cell (NCI-H226, NCI-H28, MSTO-221h). Highly ABCG2 expressing HT-29 cells represent cancer stem like phenotype including stem cell marker expression, and self-renewal bioactivities. Interestingly, we demonstrated that in vitro treatment of SLJ-496 showed significant cytotoxicity effect, as well as viral replication capacity in ABCG2 overexpressing cell. In addition, we also demonstrated the cytotoxic effect of SLJ-496 in Adriamycin-resistant cell lines, SNU-620 and ADR-300. Taken together, these findings provide us a pivotal clue that cancer therapy using SLJ-496 vaccinia virus might be new therapeutic strategy to overcome ABCG2 expressing cancer stem-like cell and multiple chemo-resistance cancer cells.