• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.289-296
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• 1990

The antimicrobial and antioxidant activities of grapefruit seed extract(GFSE), which was extracted with glycerine in the special schematic extraction apparatus, were investigated for handling and processing of fishery products. The effectivity of GFSE has been tried on sardine, mackerel and shrimp divided into six lots for each fishery product: control(no treatment) and five GFSE-treated samples. Samples were inoculated with Salmenella typhi, incubated for 24hrs at $30^{\circ}C$ in dextrose-tryptone broth medium and prepared for microbiological 8f chemical analysis and organoleptic assessment. The bacteriological analytical results with GFSE(250ppm) showed the reduction of $1.8\times10^6\to2.0\times10^4,\;1.9\times10^6\to1.8\times10^4$ and $1.6\times10^6\to2.7\times10^3$ in total bacterial count for sardine, mackerel and shrimp, respectively. The test results with GFSE(500ppm) showed a $100\%$ reduction of bacterial mackerel treated with GFSE(500ppm) was reduced to $1.1\times10^4$ and $9.0\times10^3$ respectively. Antioxidant effect of treatment with GFSE at 500ppm level for three products was significant. LSD test results on organoleptic parameter for the samples treated with various showed a significant influence on the appearance, odor and texture in which at concentration 500ppm level give the excellent scours compared to each control.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.285-295
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• 2014

This study was conducted to survey the epidemiological characteristics and the isolated strains for pathogenic E. coli which was the major causative organisms for food poisoning occurred at school food services in the Gyeonggi-do area during the past three years. We investigated 19 accidents of food-borne disease outbreaks by pathogenic E. coli at school food services from 2010 to 2012. Food-borne disease outbreaks by pathogenic E. coli were usually occurred at direct management type (18 accidents, 95%) and high schools. For the seasonal factors, 13 accidents (65%) were occurred in June to September, especially the end of August and September after the summer holidays. The first patients were occurred on Wednesday (7 accidents, 37%) and Thursday (7 accidents, 37%), and they were mainly reported on Thursday (7 accidents, 37%) and Friday (5 accidents, 26%). The exposure of risk was estimated in Monday (4 accidents, 21%), Tuesday (7 accidents, 37%) and Wednesday (4 accidents, 21%), and kimchi (5 accidents, 50%) was estimated as the food of the high risk responsible for the outbreaks. 98 isolates of pathogenic E. coli consisted of PEC (50%), ETEC (34%), EAEC (15%), and EHEC (1%). The antibiotic resistance of pathogenic E. coli showed in the descending order of ampicilline (40%), nalidixic acid (37%), trimethoprim/sulfamethoxazole (24%), and tetracycline (19%). The antibiotics of second and third generation cephalosporins, cabarpenem, aminoglycosides, and second generation quinolones had antimicrobial susceptibilities and cefalotin, ampicillin/sulbactam and chloramphenicol showed medium resistance at 29%, 25%, and 6% respectively, and 70% of isolates were resistant to more than one antibiotic. By the PFGE analysis, they were classified into nine major groups and 31 profiles with 57% pattern similarity. It was very difficult to find the correlation of antimicrobial susceptibilities and genotype in the small scale-food poisoning, but the similarity of antimicrobial resistance and PFGE patterns in the large scale-food poisoning enabled the outbreaks to estimate the same pathotype of E. coli derived from identical origins.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.29-36
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• 2004

The purpose of this work was to investigate the relationships between acrylamide degradation by Pseudomonas sp. JK-7 and several relevant physicochemical environment parameters. In initial experiments, the bacterial culture, strain JK-7 isolated from paddy soil sample was developed to grow aerobically with acrylamide as the sole source of carbon and nitrogen. The bacterium was identified as genus Pseudomonas in the basis of use BIOLOG test, and designated as Pseudomunas sp. JK-7. Strain JK-7 could degrade 50 mM acrylamide completely within 72 hours of incubation. Major intermediates resulting from acrylamide degradation were not detected with the HPLC methodology except acrylic acid which appeared to accumulate transiently in the growth medium. The pH increased from 7.0 to 8.7 with complete degradation of the initial 50 mM acrylamide within 72 hours of incubation. pH control in the range of 5 to 9 influenced the growth of JK-7 and acrylamide degradation, whereas it was not examined the growth and degradation at pH 3 or pH 11, respectively. The effect of supplemented carbons (e.g., glucose, fructose, citrate, succinate) on the acrylamide degradation by the test culture of JK-7 was evaluated. The results indicated that the addition of carbons accelerated the bacterial growth and acrylamide degradation compared to those in the absence of supplemented carbons. The effect of supplemented nitrogens on the degradation was monitored. Increasing concentrations of yeast extract resulted in higher growth yield, based on the turbidity measurement, and complete degradation of acrylamide. However, acrylamide degradation was essentially uninfluenced by the addition of $(NH_{4})_{2}SO_{4}$, $NH_4Cl$ or urea. Addition of $AgNO_3$, $CuSO_4$ or $HgCl_2$ except $ZnSO_4$ in the test culture inhibited the degradation of acrylamide and growth of JK-7.