• Analytical Science and Technology
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• 제20권4호
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• pp.347-354
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• 2007

A simple and rapid high-performance liquid chromatography assay for the determination of residual novobiocin levels in bovine, porcine, chicken, flatfish and japanese eel muscle has been developed and validated. The separation condition for HPLC/UV was optimized with phenyl hexyl ($4.6{\times}150mm$, $5{\mu}m$) column with 10 mM monobasic sodium phosphate buffer (pH 2.5)/acetonitrile (50/50, v/v) as the mobile phase at a flow rate of 1.0 mL/min and detection wavelength was set at 254 nm. Residues were extracted from tissue by blending with methanol and lipid materials were removed with n-hexane. Then, the methanol extract was evaporated to dryness under a nitrogen stream, reconstituted in the mobile phase. Aliquot of the organic extract was decanted and filtered through $0.45{\mu}m$ syringe filter. The $20{\mu}L$ of the resulting solution was injected into the HPLC system. The calibration ranges were $0.5{\sim}5{\mu}g/g$ and calibration curves were linear with coefficients of correlation better than 0.95. The limits of quantification were $0.5{\mu}g/g$ for all muscles. The recoveries of bovine, porcine, chicken, flatfish and japaneseel muscles were 99.8%, 102.4%, 91.0%, 104.0% and 93.0%, respectively. The procedures were validated according to the CODEX guideline, determining specificity, linearity, accuracy, precision, quantitation limit and recovery.

• Proceedings of the PSK Conference
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.161.2-161.2
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• 2003

In order to investigate the pathogenic genes and genetic relationships of Y. pseudotuberculosis, we isolated 9 strains of Y. pseudotuberculosis from about 380 spring water sites in Seoul and carried out antibiotic susceptibility test, biological test and molecular typing. All isolated strains were distributed throughout the northeast area in Seoul (Mt. Bookhan, Mt. Soorak, Mt. Boolam and etc...).Antibiotic susceptibility test revealed that all the strains were susceptible to chloramphenicol, gentamicin, neomycin and amoxicillin/clavulanic acid, but were resistant to novobiocin and vancomycin. (omitted)

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1621-1628
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• 2015

Chlamydia possesses a conserved 7.5 kb plasmid that is known to play an important role in chlamydial pathogenesis, since some chlamydial organisms lacking the plasmid are attenuated. The chlamydial transformation system developed recently required the use of plasmid-free organisms. Thus, the generation and identification of plasmid-free organisms represent a key step in understanding chlamydial pathogenic mechanisms. A tricolor immunofluorescence assay for simultaneously detecting the plasmid-encoded Pgp3 and whole organisms plus DNA staining was used to screen C. muridarum organisms selected with novobiocin. PCR was used to detect the plasmid genes. Next-generation sequencing was then used to sequence the genomes of plasmid-free C. muridarum candidates and the parental C. muridarum Nigg strain. We generated five independent clones of plasmid-free C. muridarum organisms by using a combination of novobiocin treatment and screening plaque-purified clones with anti-Pgp3 antibody. The clones were confirmed to lack plasmid genes by PCR analysis. No GlgA protein or glycogen accumulation was detected in cells infected with the plasmid-free clones. More importantly, whole-genome sequencing characterization of the plasmid-free C. muridarum organism and the parental C. muridarum Nigg strain revealed no additional mutations other than loss of the plasmid in the plasmid-free C. muridarum organism. Thus, the Pgp3-based immunofluorescence assay has allowed us to identify authentic plasmid-free organisms that are useful for further investigating chlamydial pathogenic mechanisms.

• Journal of fish pathology
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• 제8권2호
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• pp.99-109
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• 1995

The diseased larvae of the flounder, Paralichthys olivaceus, were sampled several times from a fish hatchery located in Cheju Island between December, 1991 and April, 1992. They turned out to be infected with Vibrio sp. and diagnosed as intestinal necrosis of flounder larvae(INFL) based on morphological, biological, and biochemical examinations. INFL was known to be caused by the live food organism infected with Vibrio sp. The optimal growth conditions of the isolates for temperature, pH, and NaCl concentration were $20\sim30^{\circ}C$, 6~8, and 2~4%, respectively. In the drug sensitivity test, the isolates were sensitive to oxytetracycline, nalidixic acid, kanamycin, and novobiocin, but resistant to ampicillin, erythromycin, spiramycin and sulfa-drug.

• Journal of Food Hygiene and Safety
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• 제25권4호
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• pp.320-324
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• 2010

Five different enrichment methods were studied to find an optimal method to recover Yersinia enterocolitica from swine feed samples. When the recovery of Y. enterocolitica GER-C (serotype O:3) strain was studied at 1000 CFU/g feed, phosphate-buffered saline (PBS) enrichment at $4^{\circ}C$ and PBS plus sorbitol and bile salts (PSB) enrichment at $4^{\circ}C$ and $21^{\circ}C$ were not effective (< 22%). In contrast, both irgasan-ticarcillin-potassium chlorate (ITC) and tryptic soy broth plus polymyxin B sulfate and novobiocin (TSBPN) enrichment methods showed a full recovery (100%) at 100-1000 CFU/g feed. At 10 CFU/g feed, both ITC and TSBPN methods still recovered the strain (> 50%). In recovery of ATCC 9610 (serotype O:8) strain, TSBPN method was more sensitive than any other methods (P < 0.05) at 1000 CFU/g feed. Using TSBPN method, the strain was still recovered at 100 CFU/g feed, but not at 10 CFU/g feed. With its sensitivity and relatively simple recipe, TSBPN was most desirable method to recover Y. enterocolitica from swine feed samples.

• Journal of Veterinary Clinics
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• 제27권1호
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• pp.6-10
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• 2010

Bacterial pathogens were isolated from dogs with urinary tract infection (UTI) in local animal hospitals between August 2003 and December 2009. Bacteria were isolated from urine of 47 dogs. The isolated pathogens were Escherichia coli (n = 27), Streptococcus spp. (n = 7), Staphylococcus spp. (n = 5), Enterobacter spp. (n = 3), Proteus spp. (n = 2), other species were 3 strains, respectively. E. coli were susceptible to imimpenem, polymyxin B, amikacin, cephalosporins, aztreonam, amoxicillin clavulate, cephalosporins, tricarcillin, and amoxicillin clavulate, while were resistant bacitracin, erythromycin, lincomycin, oxacillin, penicillin, and novobiocin. Streptococcus spp. were susceptible to bacitracin, imimpenem, and trimethoprime-sulfa, while were highly resistant amikacin, cefotaxim, cefoxitin, cloxacillin, gentamicin, lincomycin, oxacillin, penicillin, streptomycin, and tobramycin. Staphylococcus spp. were susceptible to cefoxitin, doxycycline, enrofloxacin, imimpenem, and tobramycin, but were resistant aztreonam and tetracycline.

• Korean Journal of Clinical Pharmacy
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• 제9권1호
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• pp.1-14
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• 1999

Vancomycin-resistant Enterococci (VRE) have recently emerged in Korean hospitals, as well as in those of other countries. VRE have been partially attributed to the overuse and misuse of vancomycin. The mecbanisms of VRE resistance are related to VanA, VanB, and VanC. Both VanA and VanB produce abnormal ligase enzymes to form D-ala-D-lactate termini in E. faecium and E. faecalis, instead of D-ala-D-ala termini. Meanwhile, Van C produces D-ser-D-ala termini in E. gallinarum and E. casseliflavus. These abnormal termini have a low affinity to vancomycin. As a result, VRE avoid the activity of vancomycin by these mechanisms. Unfortunately, there is no approved therapy for the treatment of VRE. Thus, available but uncommonly prescribed antibiotics (due to their toxicity or unproven efficacy) may become possible options. They include chloramphenicol, novobiocin, fosfomycin, and bacitracin. The combination therapy of available agents may also be the other options. They include high doses of a penicillin- or ampicillin-aminoglycoside combination, high doses of an ampicillin/sulbactam and aminoglyoosidcs combination, an ampicillin and vancomycin combination, and a ciprofloxacin, aminoglycosides, and rifampin combination. With respect to the near future, many types of investigational agents will most likely expand their treatment options for VRE. Teicoplanin, a glycopeptide, can be used for VanB- and VanC-related VRE. LY333328, a new generation of glycopeptide, is effective in treating VanA as well as VanB and VanC. RP59500 (quinupristin/dalfopristin), a streptogramin, is effective in treating vancomycin-resistant E. faecium. New generation quinolones (especially clinatloxacin) are potential options for the treatment of VRE, even though they cannot work as effectively against VRE as they can against Staphylococci. Both glycylcyclines (a new generation of tetracyclines) and ketolides (a new generation of macrolides) show good activity against Enterococci, regardless of vancomycin susceptibility. Oxazolidinones (i. e. eperezolid and 1inezolid) and everninomicins (i. e. SCH27899) are new groups of antibiotics, which also demonstrate good activity against VRE. It is imperative that clinical pharmacists take the responsibility of investigating new treatment options for VRE in order to combat this growing problem throughout the world.

• Current Research on Agriculture and Life Sciences
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• 제2권
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• pp.115-121
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• 1984

Some investigations on chronic mastitis in dairy cattle in Taegu-Kyungpook Provinces from the beginning of October, 1984 till the end of August, 1985 were conducted with the particular regard to the causative agents and their drug susceptibility. Milk samples from 83 isolated cases of chronic mastitis cattle were investigated bacteriologically and the causative organisms recovered were examined for their antibiotic susceptibility by using disc diffusion susceptibility technique against the major antibiotics of current veterinary use. Major causative agents involved in chronic mastitis in Taegu-Kyungpook Provinces were in order of prevalence Staphylococcus spp. (48.2 %), Escherichia coli (18.1 %), Candida spp. (10.8 %) and Corynebacterium spp. (8.4 %), Streptococcus agalactiae (3.6 %), Bacillus cereus (3.6 %) and Pseudomonas aeruginosa (2.4 %) were found to be one of the minor agents. The majority of staphylococcal isolates and E. coli were highly resistant to the most antibiotics tested. The percentages of staphylococcal cultures resistant to penicillin, methicillin, lincomycin, novobiocin, ampicillin and tetracycline were 87.2 %, 78.7 %, 68.1 %, 61.7% and 57.4 %, respectively, while the majority of them were susceptible to gentamicin(78.7 %), cephalothin(76.6 %) and chloramphenicol (74.5%). E. coli isolates were found to be highly resistant to streptomycin, cephalothin, tetracycline and ampicillin while the majority of them were susceptible to colistin (83.3 %), gentamicin (77.8 %) and chloramphenicol (66.7 %). Corynebacterium spp. were susceptible to ampicillin, chloramphenicol, erythromycin, gentamicin, oleandomycin and tetracycline although they showed resistance to novobiocin and penicillin. Two cultures of Pseudomonas aeruginosa recovered from mastitis milk were highly resistant to the antibiotics employed in the present study.

• Korean Journal of Environmental Biology
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• 제23권4호
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• pp.390-397
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• 2005

The inhibition of cell recovery might be proceeded via either the damage of the mechanism of the recovery itself or via the formation of irreversible damage which could not be repaired at all. Both these processes may take place at the same time. Any of these possibilities would result in a decrease in both the rate and extent of cell recovery. To distinguish them, a quantitative approach describing the process of recovery as a decrease in the effective radiation dose was applied to experimental data on the recovery from potentially lethal damage in Chinese hamster cells exposed to X-rays alone or combined with various chemicals (pyruvate, novobiocin, lactate, nalidixic acid, 3-aminobenzamide). For these particular cases, it is concluded that the recovery process itself is not damaged and the inhibition of the recovery is entirely due to the enhanced yield of the irreversibly damaged cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.61-61
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• 1995

1993년 국내토양으로부터 분리동정된 Streptomyces속 균주중 항종양성이 우수한 균주 3주(DKM104, DKM117, DKM409)를 선정하고 이들을 대량 배양하여 종양억제인자를 분리하고 시험관내 종양세포 독성능 및 생체내 항암활성능과 이들 물질생산과 PLASMID DNA와의 관련성, $LD_{50}$등을 시험하여 새로운 항종양물질의 개발을 목적으로 하였다. 분리선별균주의 배양조건을 확립하였으며 배양여액을 국성이 적은 유기용매로부터 큰쪽으로 단계적으로 유효성분을 추출하여 Gel Chromatography를 이용하여 유효성분을 분획하였다. 시험관내 항종양능 시험은 MTT colorimetric검정법을 이용하여 $IC_{50}$값을 산정하였으며 생체내 항종양능은 마국의 NIC에서 권장하는 tumor panel system에 따랐다. 선정된 균주의 plasmid 분리는 alkalin lysis법을 채택하였으며 agarose gel electrophoresis로 plasmid profile을 시험하였다. Novobiocin등을 이용하여 Curing test를 시행하였고 독성실험은 $LD_{50}$량을 구해 항암효과 측정시에 Maximum dost로 투여하였고 최고용량을 기준으로 일정한 공비를 적응하여 3단계의 투여량을 설정하였다.(중략)