• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6757-6760
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• 2013

Gastric cancer is one of the most frequently occurring malignancies in the world. Development of multiple drug resistance (MDR) to chemotherapy is known as the major cause of treatment failure for gastric cancer. Multiple drug resistance 1/P-glycoprotein (MDR1/p-gp) contributes to drug resistance via ATP-dependent drug efflux pumps and is overexpressed in many solid tumors including gastric cancer. To investigate the role of MDR1 knockdown on drug resistance reversal, we knocked down MDR1 expression using shRNA in drug resistant gastric cancer cells and examined the consequences with regard to adriamycin (ADR) accumulation and drug-sensitivity. Two shRNAs efficiently inhibited mRNA and protein expression of MDR1 in SGC7901-MDR1 cells. MDR1 knockdown obviously decreased the ADR accumulation in cells and increased the sensitivity to ADR treatment. Together, our results revealed a crucial role of MDR1 in drug resistance and confirmed that MDR1 knockdown could reverse this phenotype in gastric cancer cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.508-515
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• 2014

The contamination status of Vibrio parahaemolyticus in commercially valuable shellfish from the south and west coasts of Korea and the antimicrobial resistance patterns of isolated V. parahaemolyticus were investigated from July through October, 2011. The range of V. parahaemolyticus concentrations in oysters Crassostrea gigas and short neck clams Venerupis philippinarum was <30~290 MPN/100 g and <30~46,000 MPN/100 g, respectively, and greater than 10,000 MPN/100 g of V. parahaemolyticus was detected from 7 of 40 short neck clams. During the survey period, 436 strains of V. parahaemolyticus were isolated (129 from oysters and 307 from short-neck clams) and the antimicrobial resistance patterns of all of the isolates were examined. Antimicrobial resistance against at least one antibiotic was seen in 79.8% of the oyster isolates (103 strains) and 63.8% of the short neck clam isolates (196 strains). The antimicrobial resistance patterns were relatively simple because the antimicrobial resistance of the isolates was simply due to resistance to ampicillin. Only one oyster isolate and three short neck clam isolates showed multiple antibiotic resistance, i.e., resistance against more than four antibiotics.

• Biomedical Science Letters
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• v.5 no.1
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• pp.17-26
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• 1999

To evaluate the spreading possibilities of the marRAB mutation of E. coli Mar mutant among gram-negative bacilli, chromosomal marRAB mutations of Mar mutants were transduced by $\lambda$placMu9 into pUC19 (Lac$^{+}$, Ap$^{r}$) cloning site in another strains of E. coli or onto the chrmosome of S. typhimurium and P. aeruginosa, selected for transduction by Mar phenotype, Lac$^{-}$, or Ap$^{r}$, and tested for their antimicrobial resistance with or without addition of salicylate (SAL). Compared with wild type strains of JM109, NM522, harboring pUC19 or not, respectively, all strains of JM109 or NM522 carrying pUC19::marRAB mutation showed higher levels of antimicrobial resistance and SAL induction of Mar phenotype than those of wild type. However, in contrast to the original Mar mutants, there were some tendencies of decreased antimicrobial resistance of JM109 or NM522 harboring pUC19::marRAB mutation with SAL induction against chlorarnphenicol (Cm) and tetracycline (Tc), or Tc and ciprofloxacin (Cp), respectively. Almost the same results, as shown as the cases of E. coli JM109 or NM522, were obtained from all transductants of S. typhimurium and P. aeruginosa, except Cp, against which increased antimicrobial resistance with SAL induction was shown. This study, employed the methods of transformation or transduction among intercellular gene transfer methods between gram-negative bacteria, shows the evidences that suggest indirectly the spreading possibilities of marRAB mutation among gram-negative bacilli.

• The Journal of the Korean Society for Microbiology
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• v.5 no.1
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• pp.1-8
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• 1970

This report is to observe the rate of multiple resistance to various antibiotics among staphylococcus aureus and E. coli which were isolated with high frequency at our department during 1969. 1. One hundred fifty two strains(20.6%) resistant to four antibiotics multiple resistant was the highest incidence among 739 strains of Staphylococcus aureus. 2. Regarding the multiple antibiotic resistant of Staphylococcus aureus, 75strains(10.1%) to SA. PC. TC the three antibiotics resistant, have been observed, with the highest incidence, and next to this, 69 strains(9.3%) to SA. PC. SM. TC the four autibiotics resistant, and 68 strains(9.2%) to SA. PC. SM. CM. TC. SM. the six antibiotics resistant, have been observed in descending order. 3. The case of one hundred twenty seven strains(28.0%) of the six antibiotic multiple resistant among 454 strains of Escherchia coli was the highest incidence. 4. Concerning the multiple antibiotic resistant of Escherichia coli, 70 strains(l5.4%) to SA. SM. CM. TC. EM. FD. the six antibiotics resistant, have been observed, with the highest incidence, and next to this, 59 strains(l3.0%) to SA. SM. CM. TC. EM. FD. AC the seven antibiotics resistant, and 42 strains(9.3%) to SA. SM. CM. TC. EM. FD. KM. AC the eight antibiotics resistant have been observed in descending order.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.827-833
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• 2011

In this study, fecal nonpoint pollutant sources tracking were conducted on Ansan stream. Multiple Antibiotic Resistance Analysis (MARA) method used in this study is based on the premise that fecal bacteria derived from intestine of human or animal has each different resistance for antibiotics. First of all, a database for known sources should be established to use the method and then, an unknown sample was applied on the database to find unknown sources by statistical analysis. The Ansan stream was considered with divided condition into three parts: upper (livestock farming area), mid (old section of the city), and downstream (new section of the city) to search an environmental influence of the stream basin. As results of the statistical analysis, it could be estimated that the upper stream area was influenced by animals due to the nature of influence for the livestock farms located in this area because livestock were classified as percentages of 45.8% in 3-way method divided into livestock, pet and human. In case of midstream and downstream, the human influence was remarkable as percentage of 60% and 80%, respectively. From these results, it could be judged that the MARA method is useful in source tracking the non-point pollutant sources because the MARA results correspond to which predictable non-point pollutant sources by a field study. Also, it is expected that a more effective source tracking will be possible as establishing database of each area.

• Korean Journal of Poultry Science
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• v.42 no.1
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• pp.27-32
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• 2015

In this study, we used two breeds of chicken to identify genomic regions corresponding to necrotic enteritis (NE) resistance. We scanned the genomes of a resistant and susceptible line of Fayoumi and White Leghorn chickens (20 birds/line) using a chicken 60 K Illumina SNP panel. A total of 235 loci with divergently fixed alleles were identified across the genome in both breeds; particularly, several clusters of multiple loci with fixed alleles were found in five narrow regions. Moreover, consensus 15-SNP haplotypes that were shared by the resistant lines of both breeds were identified on chromosomes 3, 7 and 9. Genes responsible for NE resistance were identified in chicken lines selected for resistance and susceptibility. Annotation of the regions spanning clustered divergently fixed regions revealed a set of interesting candidate genes such as phosphoinositide-3-kinase, regulatory subunit 5, p101 (PIK3R5) and inositol 1,4,5-trisphosphate receptor 1 (ITPR1), which participate in immune response. Consensus haplotypes were found in regions containing possibly relevant genes, such as myostatin and myosin, which play important roles in muscle development. Thus, genome scans of divergent selection in multiple chicken lines and breeds can be used to identify genomic regions associated with NE resistance.

• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.511-521
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• 2001

Microorganisms were isolated and identified from bovine 296 quarters which showed positive reaction by California Mastitis Test (CMT) in 40 farms of Jeju from September 1999 to June 2000. The organisms associated with the mastitis of bovine were 11 different bacterial species in this study. Which of them, Staphylococcus aureus was the most predominant species as 152 (51.4%) isolates. Other identified species included 49 (16.5%) coliform, 47 (15.8%) Streptococcus dysgalactiae, 15 (5.1%) Bacillus spp., 8 (2.7%) Staphylococcus epidermidis, 6 (2.1%) Streptococcus agalactiae, 5 (1.7%) Enterococcus faecalis, 5 (1.7%) Corynebacterium spp., 3 (1.0%) Streptococcus uberis, 1 (0.3%) Pseudomonas aeruginosa and 1 (0.3%) Pasteurella haemolytica. Almost of all the islolated beacterial species showed high sensitivity against kanamycin (98.6%), cephalothin (98.0%), streptomycin (94.9%), gentamicin (94.6%), ampicillin (92.2%) and polymyxin B (90.2%). On the contrary, they showed resistance against penicillin (47.0%), tetracycline (37.2%), cefazolin (26.0%), bacitracin (22.6%) and erythromycin (19.9%). Eighty-one isolates were not resistant to any antibiotics and 215 drug resistant isolates showed 89 different drug resistance patterns from single to nine multiple antibiotics resistance patterns.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.116-119
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• 2007

The antimicrobial susceptibility and antibiotic resistance patterns of 67 eae positive Escherichia coli strains isolated from pigs were investigated by disc diffusion method. Sixty-seven E. coli isolated from pigs showed susceptibility to Ceftiofur (98.5%), Lincomycin+Spectinomycin (74.6%), Danofloxacin (73.1%), Enrofloxacin (64.2%), and Neomycin (41.8%). However, the multiple resistance patterns were also seen in eae+E. coli isolates. Neomycin+Tylosin+Penicillin+Tetracycline, Tylosin+Penicillin+Tetracycline, and Neomycin+Tylosin+Danofloxacin+Penicillin+Tetracycline+Enrofloxacinwere the most prevalent patterns of multiple antibiotic resistance.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.682-688
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• 1998

Fungicide resistance of 48 isolates of Botrytis cinerea collected from citrus in Cheju was investigated and genetic diversity was analyzed with random amplified polymorphic DNA(RAPD). High levels of resistance to benzimidazole fungicides benomyl and thiophanate-methyl and N-phenylcarbamate fungicide diethofencarb were observed. Negative cross resistance was clear between benzimidazole and N-phenylcarbamate fungicides, and multiple resistance to the fungicides was also observed. There was cross resistance among the dicarboximide fungicides procymidione, vinclozolin and iprodione as it was observed between the benzimidazole fungicides benomyl and thiophanate-methyl. The lowest levels of resistance were to the dicarboximide fungicides, but no sensitive isolate to polyoxin B was observed. The isolates showed genetically diverse RAPD profiles according to the geographic origin collected, but there was no significant correaltion between RAPD profiles of genomic DNA and the levels of fungicide resistance of the isolates. The isolates showed genetically diverse RAPD profiles, indicating that genetic differentiation had already occurred in the populations of B. cinerea distributed in Cheju.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1564-1570
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• 2016

This study proposes a newly modified form of existing ground electrodes in order to secure trust of grounding system for large current caused by a stroke of lightning. Proposed planar earth structure has a several needle electrodes around a circular rod and 4 plane electrodes in all directions. The plane electrodes are fused with the insulator on the linear rod, so that they're electrically isolated. The concept is to increase the discharge amount of earth structure using multiple discharge paths like needle and plane electrodes. To check the discharge efficiency of the suggested scheme, the discharge currents are compared with typically used two kinds of ground rods. To ensure accuracy in the measurement of the discharge current, the same material was used for the comparison model. Also, the ground resistance are simulated by CDEGS commercial software and the results are compared with measured data. Based on this kind of experimental study, the suggested ground rod can be used when designing a ground system or when constructing a ground system at the site.