• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.64-64
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• 2003

대구 인공종묘 생산 기술 개발의 일환으로 수정란에 기생하여 폐사를 유발하는 세균 및 세균 감염 경로를 파악함으로써 수정란의 생존율과 부화율 향상을 위하여 본 실험을 실시하였다. 세균 감염 경로를 파악하기 위하여 난소와 정소 자체 세균 감염 여부를 조사하였다. 일반배지 (BHIA)와 비브리오 선택배지 (TCBS)를 사용하여 세균검사를 실시하였다. 난소의 세균 검사는 생식소 내부를 일부 절개한 후 멸균 roop를 찔러 세균을 검사하였고, 정소는 채정하기 전 복부를 절개하여 멸균 roop로서 적출하여 배지에 도말한 후 배양하였다. 수정란 내 세균 수는 수정란을 각각 20개씩 샘플하여 난 외부에 기생하는 세균을 제거하기 위하여 난소독제로 이용되고 있는 benzalkonium 0.1%로 1분간 소독한 후 멸균 생리식염수로 3회 세척하여 호모게나이즈하여 검사하였다. 호모게나이즈한 액 중 100${\mu}\ell$를 pipetting하여 일반배지(BHIA)에 도말하여 인큐베이터에서 배양하였다. 난소와 정소 내에서 세균이 검출됨에 따라 수정 시 세균 감염을 억제하기 위하여 자외선 살균해수와 일반해수를 수정액으로 사용하여 발생율을 비교 시험하였다. 수정 시간은 1분으로 동일하게 적용하였으며, 수정 용기는 멸균 처리된 일회용 100$m\ell$ 플라스틱 용기를 사용하였다. 수정 후 과다한 정자를 제거하기 위한 세란은 1$\ell$ 멸균 비이커에서 5회 30분 가량 실시하여 정자를 제거하였고 멸균 봉으로 저어주면서 수정란의 점착력을 제거하였다. 수정란은 100$\mu\textrm{m}$ 그물망으로 수정란 유실을 방지한 플라스틱 용기에 수용하여 유효수량 270$\ell$ FRP 수조에 수용하여 3$\ell$/min 환수하였고, 수온은 자연수온 1$^{\circ}C$로 유지하였다. 발생율은 만능투영기로 3회 측정하였다. 수정 후 세균과 기생충에 의한 수정란의 폐사를 억제하기 위하여 수정 직후, 수정 후 1일, 2일째 oxytetracycline과 iodine 처리에 따른 발생율 변화를 조사하였다. 발생율은 만능투영기로 조사하였고, 시험구별로 3회 측정하였다. 경과 일수별로 약제 처리는 약제 미처리 수정란 중 정상적인 발생이 이루어지고 있는 것을 선별하여 조사하였다. 약제 처리에 따른 배체 발생 단계는 수정 후 1일째는 상실기, 2일째는 포배기였다. 수정란 및 대구 자어에서 분리된 V. splendidus 에 의한 폐사를 예방하기 위해 in vivo에서 oxytetracycline 외 5종의 항생제를 대상으로 96well plate에서 최고 농도 250ppm부터 2 fold로 단계 희석하여 $25^{\circ}C$에서 48시간 배양하여 MIC를 조사하였다. 세균 감염경로 파악을 위하여 난소, 정소 및 정자에서 세균을 분리한 결과 일반배지 및 비브리오 선택배지에서 모두 균이 검출되었고, 균 동정 결과 터봇 자어에서 검출된 것으로 보고된(Gatesoupe et al., 1999) V. splendidus로 나타났다. 수정액과 정자 및 미수정란의 세균 분리 결과 일반배지에서 3$\times$10/ml ~ 7$\times$10/ml로 균이 검출되었다. 수정액을 일반해수와 자외선 살균 해수를 사용하여 발생율을 비교한 결과 수정 후 3일째 발생율은 자외선 살균해수 72.3%, 일반해수 52.7%였으며, 수정 후 7일째 40.9%와 25.1%로 자외선 살균해수가 유의적으로 높게 나타났다. 수정 후 경과 일수별로 oxytetracycline과 Iodine을 처리한 결과 수정 직후 처리한 시험구는 7일째 19.8%와 18.9%로 대조구 23.1%와 유의적인 차이가 없는 것으로 나타났다. 수정 후 1일째 처리한 시험구는 54.5%와 56.8%, 수정후 2일째 처리구는 47.9%와 50.6%로 두 시험구 모두 대조구와 수정 직후 처리구보다 유의적으로 높게 나타났다. 수정란 및 대구 자어에서 분리된 V. splendidus 에 의한 폐사를 예방하기 위해 in vivo에서 항생제 종류별 MIC 조사 결과 oxytetracycline이 0.48ppm으로 가장 효과가 높은 것으로 나타났다.

• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.101-108
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• 1985

Histopathological changes in the witches'-broom mycoplasma (MLO) infected jujube trees after trunk injection of oxytetracycline HCl (OTC) solution were investigated by using light microscope, fluorescence microscope and electron microscope. In contrast to the healthy leaves, adaxial and abaxial bundle sheath extensions in the major veins of diseased leaves were highly developed, but mesophyll cells were very small, loose and necrosed. In the diseased leaves, excessive phloem was formed, xylem differentiation was supressed and polyphenols were accumulated. Jujube trees treated with 500ml of 2000ppm solution of OTC showed complete remission of witches'-broom symptoms above the injection site, but cells in the sheath extention were hypertrophied and sieve tube necrosis occurred in the secondary phloem of major veins. MLO-specific fluorescence was not observed in the samples of diseased jujube trees treated with OTC, while those from non-treated infectedstress distinctly showed a moderate amount of MLO-specific fluorescence. In the observation under the electron microscope, sieve element of diseased tissues and its associated companion cells were found to have collapsed. Parenchymas cells contained many large starch filled plastids and most samples of diseased and OTC-treated tissues showed an abnormal accumulation of starch compared to the healthy controls. Mycoplasma-like organisms were observed only within mature sieve elements in diseased tissues, but never in OTC-treated tissues.

• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.12-16
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• 1993

Post-harvest trunk injection of oxytetracycline-HCl(OTC) was attempted for the control of jujube witches'-broom. Diseased jujube(Zizyphus jujuba) trees with 9 to 16cm trunk diameters were treated with OTC ranged from 2g to 6g according to the size of trunk diameter. OTC dissolved in 0.51 or 1.01 of water was transfused into diseased trees by gravity flow injection during September and October. All these OTC concentrations prevented symptom development for two growing seasons and restored previously severely diseased trees to normal conditions. There was no differences in control effect between 0.51 and 1.01 OTC solutions. With these high OTC concentrations, no phytotoxicity was observed in the new leaves of the following year. Mycoplasma -like organism (MLO)-specific fluorescence was absent in the phloem of recovered tissue when examined by fluorescence microscopy using DAPI(4'-6-diamidino-2-phenylindole.2HCl) staining, indicating the disappearance of MLO by the action of OTC.

• The Journal of the Korean Society for Microbiology
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• v.12 no.1
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• pp.1-10
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• 1977

40 strains of E. coli isolated from residents of a doctorless area in Korea in 1976 and 40 strains of E. coli isolated from patients of Seoul National University Hospital from 1975 to 1976 were examined for susceptibilities to 14 antimicrobial agents by the agar dilution method. The susceptibilities of the two groups to each antimicrobial agent were compared and correlations in the antimicrobial susceptibility of the 80 strains of E. coli among the 14 antimicrobial agents were also analyzed. The results were obtained as follow: 1. With Tetracycline, Oxytetracycline, Doxycycline and Ampicillin, the mean MIC's of E. coli isolated from patients of Seoul National University Hospital were 8.6 to 14 times higher than. those of E. coli isolated from residents of a doctorless area. 2. With Streptomycin, Minocycline and Carbenicillin, the mean MIC's o{ E. coli isolated from patients of Seoul National University Hospital were 4.1 to 5.6 times higher than those of E. coil isolated from residents of a doctorless area. 3. With Kanamycin, Penicillin and Cotrimoxazole, the mean MIC's of E. coli isolated from patients of Seoul National University Hospital were 2.6 to 3.7 times higher than those of E. coli isolated from residents of a doctorless area. 4. There were no significant differences in susceptibility to Erythromycin respectively between E. coli isolated from patients of Seoul National University coli isolated from residents of a doctorless area. 5. E. coli isolated from patients of Seoul National University Hospital were resistant to Erythromycin(100%), Streptomycin(75%), Tetracycline(72.5%), Oxytetracycline(72.5%), Doxycycline(72.5%), Minocycline(67.5%), Penicillin(82.5%), Ampicillin(60%) and Carbenicillin(65%) respectively and were sensitive to Gentamicin(97.5%), Cephalexin(92.5%) and Kanamycin(72.5%) respectively. 6. E. coli isolated from residents of a doctorless, area were resistant to Erythromycin(100%), Streptomycin(40%) and Penicillin(50%) respectively and were sensitive to Gentamicin(100%), Kanamycin(92.5%), Tetracycline(87.5%), Oxytetracycline(87.5%), Doxycycline(87.5%), Minocycline(87.5%), Ampicillin(95%), Carbenicillin(92.5%) and Cephalexin(97.5%) respectively. 7. There were high correlations among the suscebtibilities of the 80 strains of E. coli to Tetracycline analogues(Tetracycline, Oxytetracycline, Doxycycline and Minocycline) and among susceptibilities of the 80 strains of E. coli to Penicillin analogues(Penicillin, Ampicillin and Carbenicillin). 8. There were relatively high correlations between the susceptibilities of the 80 strains of E. coli to Penicillin analogues and those to Tetracycline analogues, between the susceptibilities to Penicillin analogues and those to Streptomycin and between the susceptibilities to Tetracycline analogues and those to Streptomycin.

• Journal of fish pathology
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• v.25 no.2
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• pp.123-126
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• 2012

Exfoliation of fouling abalone, Haliotis discus hannai from shelters by commercial oxytetracycline (OTC) was observed in culture farms. In the present study, different components of OTC for exfoliation of abalone were investigated to understand how to work. Abalone were detached from shelter in 14,000 ppm of commercial OTC (main ingredients of OTC: OTC-hydrogen chloride (HCl), 50%; glucose, 49%; blue pigment, <1%), but not below 8,000 ppm. A 95% of exfoliation rate was observed in OTC-HCl (7,000 ppm, pH 2.8) but no exfoliation in OTC-HCl (7,000 ppm, pH 5.0), glucose (7,000 ppm) or blue pigment (140 ppm). Moreover 100% exfoliation rate was observed in HCl-seawater of pH 2.8. These results indicate that HCl is the component resulting in exfoliation of the fouling abalone. Abalone was detached in HCl solution (pH 2.5-3.2) within 2 min. However, a lower pH and longer treatment resulted in delayed recovery of the detached abalone. Thus, exfoliation of fouling abalone can be achieved by a low pH treatment with cautious handling.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.259-266
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• 1994

The study was carried out to determine the pharmacokinetic parameters after intravenous(iv) and intramuscular(im) administration (10mg/kr) in healthy rabbits. The results obtained through the experiments were summarized as follows: 1. Bioassay (Bacillus cereus 11778) was evaluated very useful for the determination of oxytetracycline(OTC) in the rabbit serum and tissues, with the detection limit of $0.125{\mu}g/ml$. 2. The pharmacokinetic profiles of OTC (10mg/kg, iv) in rabbits were best described with a two compartment open model $(C=29.5e^{-4,3t}{\pm}3.6^{-0.2t})$, whereas that of OTC (10mg/kg, im) showed a one compartment curve fitting. 3. Following iv administration, a rapid distribution phase was predominant [$t_{\frac{1}{2}}({\alpha}):1.43{\pm}0.98hr$ (♂), $0.5{\pm}0.1hr$(♀)], and then more slow elimination phase ensued [$t_{\frac{1}{2}}({\beta}):4.52{\pm}0.76hr$(♂), $7.32{\pm}2.52hr$(♀)]. Other computer generated pharmacokinetic values were as follows:C1 [$67.76{\pm}18.59ml/kg/h$(♂), $76.03{\pm}22.98ml/kg/h$ (♀)] Vd [$257.74{\pm}180.47ml/kg$ (♂), $92.33{\pm}23.62$ (♀)] AUC [$25.6{\pm}4.44mgh/L$ (♂), $39.6{\pm}12.13mgh/l$ (♀)]. There were no statistical significance between both sexes for all the parameters at the confidence level of 95%. 4. After im administaration, the absorption from the injection sites was very rapid [ Ka:$0.18{\pm}0.03h^{-1}$ (♂), $0.24{\pm}0.02h^{-1}$ (♀)] followed by a monoexponential elimination fashion. The time to peak blood level (Tmax) were calculated $1.64{\pm}0.15hr$ and $1.34{\pm}0.24hr$, in the male and female, respectively. The peak levels (Cmax) at the corresponding time were $1.69{\pm}0.23{\mu}g/ml$ (♂) and $2.08{\pm}0.16{\mu}g/ml$ (♀), with no statistical differences (p>0.05).

• Journal of fish pathology
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• v.22 no.1
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• pp.91-95
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• 2009

The pharmacokinetic properties of oxytetracycline (OTC) were studied after intramuscular injection to cultured olive flounder, Paralichthys olivaceus. Plasma concentrations of OTC were determined after dosage of 12.5, 25 and 50 ㎎/㎏ body weight in olive flounder (average 600 g, $23{\pm}1{^{\circ}C}$). Plasma samples were taken at 3, 5, 10, 15, 24, 32, 48, 72, 120, 168, 240 and 360 h post-dose. With 25 and 50 ㎎/㎏, the peak plasma concentrations of OTC, which attained at 5 h post-dose, were 0.99 and 1.49 $\mu{g}/m\ell$, respectively. However, the peak plasma concentration of 12.5 ㎎/㎏ was 0.35 $\mu{g}/m\ell$ after 10 h post-dose. Plasma concentrations of OTC were not measurable at 360 h post-dose in all doses. The kinetic profile of absorption, distribution and elimination of OTC in plasma were analyzed fitting to a 1-compartment model by Win-Nonlin program. The following parameters were calculated for 12.5, 25 and 50 ㎎/㎏ body weight, respectively: AUC (the area under the concentration-time curve)?D���D24.98, 44.67 and 50.45 $\mu{g}$ $h/m\ell$ $T_{1/2}$ (half-life) ?D���D0.42, 0.59 and 0.41 h; $T_{max}$ (time for maximum concentration)?D���D8.46, 6.34 and 2.66 h; $C_{max}$ (maximum concentration)?D���D0.30, 0.63 and 1.13 $\mu{g}/m\ell$.

• Journal of Life Science
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• v.25 no.2
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• pp.151-157
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• 2015

Zebrafish (Danio rerio) has been more widely used to study pharmacology. Oxytectracycline (OTC) is a broad-spectrum antibiotic and works by interfering with the ability to produce essential proteins of bacteria. The aim of this study was to identify the effects of exposure to OTC on behavioral changes or endocrine response in zebrafish. The behavioral effects of exposure to OTC (50, 100 or 200 mg/l) were characterized in several novelty-based paradigms such as the novel tank or open field test in zebrafish. Moreover, to investigate effects of exposure to OTC on endocrine response, we measured whole-body cortisol level using cortisol ELISA kit. As results of novel tank test, duration in top and immobile duration were significantly increased by the exposure to OTC in a concentration-dependent manner (p<0.05). In addition, moving distance, highly mobile, velocity and zone transition were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). As results of open field test, the exposure to OTC increased immobile duration significantly (p<0.05). However, moving distance, mobile duration and velocity were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). Besides, the exposure to OTC elevated whole-body cortisol levels in zebrafish. These results suggest that the exposure to OTC may induce chemical stress in zebrafish.

• Journal of Aquaculture
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• v.17 no.4
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• pp.268-274
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• 2004

Olive flounder was treated with oxytetracycline (OTC) and changes in blood physiology, antioxidant enzymes and heat shock protein (HSP) were recorded to obtain preliminary data for optimal OTC treatment. Blood parameters were measured 1 and 3 h after the OTC treatments at the concentration of 0 (control), 100, 300 and 500 ppm for I h. Hematocrit decreased with time, however the difference was not significant (P>0.05). Reduced number of red blood cell was observed with increasing OTC concentration. Serum glucose level increased as the OTC concentration increased. However, glucose level was similar to control after 3 h. Blood total protein decreased immediately after the OTC treatment but increased after 1 and 3 h. However, the increment in blood total protein was low. Activities of superoxide dismutase enzymes in 300 and 500 ppm groups increased by the OTC concentration. Catalase enzyme activity was negatively affected by the OTC concentration. However, the differences were not significant (P>0.05). High expression of HSP-70 protein was recorded for groups treated with 100 and 500 ppm compared to that of the control group. However HSP-70 mRNA showed a lower increment which was not significant (P>0.05).

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.641-650
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• 2022

The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.