• Journal of fish pathology
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• v.13 no.1
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• pp.45-51
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• 2000

Bacterial diseases with mixed infection have recently occurred at land-based flounder farms in Korea. Thus, single antibacterial is not effective for therapy of mixed bacterial diseases of fish because of their different causative bacteria. The purpose of the present study was to obtain basic data for positive usefulness of a combination of antibacterials used for synergism to mixed bacterial diseases of fish. Snergistic interaction in combination of antibacterials was determined by in vitro antimicrobial activity against selected fish-pathogenic bacteria, Vibrio anguillarum, Edwardsiella tarda, Streptococcus sp., Staphylococcus epidermidis, on the basis of Checkerboard assay using fractional inhibitory concentration (FIC) indices. Synergistic interactions were observed in combinations of (oxytetracycline HCL+lincomycin), (tetracycline HCL+florfenicol), (oxytetracycline HCL+florfenicol) against V. anguillarum, (sodium nifurstyrenate+florfenicol), (tetracycline HCL+florfenicol), (sodium nifurstyrenate+oxolinic acid), (oxytetracycline HCL+florfenicol) against E. tarda, (ciprofloxacine+oleandomycin), (oxytetracycline HCL+oleandomycin), (tetracycline HCL+oleandomycin), (oxytetracycline HCL+lincomycin), (oxytetracycline HCL+spiramycin), (oxytetracycline HCL+erythromycin), (doxycycline HCL+oleandomycin), (tetracycline HCL+spiramycin) against Streptococcus sp., and (ciprofloxacine+erythromycin), (florfenicol+erythromycin), (doxycycline HCL+oleandomycin), (ciprofloxacine+oleandomycin) against S. epidermidis.

• 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.

• 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.

• Korean journal of applied entomology
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• v.15 no.3 s.28
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• pp.107-110
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• 1976

A Witches'-broom disease of jujube (Zizyphus jujuba) with which mycoplasma-like bodies are associated is wide spread in South Korea. Jujube trees with witches'-broom symptoms were selected from 15-20 year old planting and treated with solution of oxytetracycline hydrochloride (Terramycin). Treatments were 1) one injection on April; 2) one postharvest injection on October; 3) two injections (April and July); 4) three injections (April, June and August) and 5) an untreated control. Each injection consisted of 500ml of 1,000 p.p.m. solution of oxytetracycline HCl transfused into affected trees from plastic reservoir through plastic tubes connected to 3 small holes drilled in the basal part of the tree trunks. Complete remission of witches'-broom symptoms was accomplished within one growing season by one spring (April) injection. One postharvest (Oct.) injection also prevented the symptoms in the following growing season. Two and three injection treatments prevented the symptoms for at least two growing seasons and restored previously severely diseased trees to normal or near normal conditions. Remission of symptoms was found only above the injection site while current season witches'-brooms developed from areas below the injection site and from untreated main scaffolds. The results of this experiment demonstrates that transfusion treatment with oxytetracyclin HCl is feasible for the practical control of witches'-broom of jujube.

• Journal of fish pathology
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• v.26 no.1
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• pp.51-56
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• 2013

It is reported that abalone, Haliotis discus hannai, was detached from shelters by commercial oxytetracycline (OTC) dissolved in hydrochloric acid (HCl). In the present study, we investigated the exfoliation effect of fouling abalone by organic acids instead of OTC or HCl. Organic acids (malic acid, citric acid, lactic acid and formic acid) of pH 2.6 and pH 2.1-2.3 exfoliated over 67.6% and 91.7% of abalone, respectively; while OTC of pH 2.6 and pH 2.1-2.3 exfoliated 25.9% and over 74.1% of abalone, respectively. These results indicate that the exfoliation effect of organic acid is better than that of OTC dissolved in HCl at the same pH. However, a lower pH and longer treatment of organic acids resulted in delayed recovery of the detached abalone; abalone immersed in pH 2.3 for 10 second was recovered within 5 min, but took 12 min to recover after 30 second immersion. Moreover, recovery period for abalone exposed to pH 2.1 for 30 second was at least 15 min 45 second. In conclusion, though acids need to be cautiously handled, organic acids may be a better candidate to detach abalone instead of OTC or HCl.

• 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.

• 동물약계
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• no.71
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• pp.3-4
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• 2000

[ $\cdot$ ]구제역 방역훈련(CPX) 참관 $\cdot$미량광물질제제 품질관리 협의회 개최 $\cdot$'전국 소독의 날' 소독제 지원 $\cdot$유럽 사료첨가제 제조$\cdot$사용실태 견문 $\cdot$동물약사감시 행정처분 결과 홍보 $\cdot$긴급 이사회 개최 $\cdot$동물약품 제조용 유당 증량 배정 $\cdot$민족통일 염원 금강산 등반대회 개최 $\cdot$Oxytetracycline hcl. 알선 오퍼상 선정 $\cdot$한국동물약품협회장배 회원 체육대회 개최

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.910-916
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• 2022

The purpose of this study is to evaluate the effect of underwater non-thermal dielectric barrier discharge plasma (DBD plasma) on the sterilization of three types of pathogenic bacteria that cause diseases in freshwater fish and the reduction of a tetracycline antibiotics. This experiment was conducted in the DBD plasma generator, and the voltages used to generate plasma were 11.6 kV and 23.1 kV. The measurement intervals were 0, 1, 5, 10 and 15 min. As a result of DBD plasma treatment, Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens were removed 93-99% after 5 min at 23.1 kV, and the tetracycline antibiotics were reduced 70-95% after 15 min at 23.1 kV. In this study, as a result of treating the effluent with DBD plasma at a fish farm where the medicinal bath was conducted with oxytetracycline-HCl (OTC-HCl) products, OTC-HCl decreased by 62% after 10 min at 23.1 kV.

• Journal of Korean Society of Forest Science
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• v.49 no.1
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• pp.6-10
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• 1980

The witches' broom disease of Paulownia tomentosa (Thunb.) Steud with which mycoplasmalike organisms are associated is widespread throughout Korea and poses serious threat to the cultivation of paulownia. Attempt was made to investigate the feasibility of field control of the disease with oxytetracycline hydrochloride (OTC). A total of 84 paulownia trees (6 year-old, DBH: 10-15cm) exhibiting severe symptoms of witches' broom were selected and treated during March to September. Solution of 1-10g of OTC dissolved in 0.1­2.0 of water was transfused into infected trees with gravity flow method from a dark-brown colored plastic reservoir (11 volume) through plastic tubes (1.2m long) connected to 2-4 holes (5 mm in diameter and 4-5cm in depth) bored in the basal part of the tree trunks (Fig. 1 and 2). Of 60 diseased paulownia trees injected with 2g of OTC in 0.1-2.0l of water during May to September, 1979, 58 trees resulted in complete remission of symptom development and resumption of healthy new growth at least up to September, 1980 when the last observation of the effect of OTC treatment for this experiment was made. The rest of two trees were dead probably due to too severe infection. Of 24 paulownia trees treated in March and April, 1979 complete remission of symptom development was obtained with 8 trees, and nine trees were partially prevented from symptom development in the following season. The remaining 7 trees were dead due to failure in uptake of OTC and partly because the trees were in too far advanced stage of infection. Application of highly concentrated solution of 2g of OTC dissolved in 0.1-0.2l of water per tree was just as effective as the 2g/1-2l treatment. Injection of 2g/1-2l required 3-4 days while treatment of 2g/0.1-0.2l reduced the time for injecting one tree down to less than 24 hrs. The result of this experiment demonstrates that basal trunk injection of 2g OTC/0.1-0.2l/tree is feasible for field control of paulownia witches' broom, provided that tree injection is performed in actively growing season (May-September) and at the initial stage of disease development.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.129-134
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• 2002

To isolate probiotic lactic acid bacteria having superior inhibitory activities against animal gastro-intestinal pathogenic bacteria such as Salmonella gallinarum, Staphylococcus aureus and Escherichia coli, 130 strains were initially isolated from the small intestines of Korean native chickens and 7 lactic acid bacteria were finally selected. By using API CHL kit and 16S rRNA sequencing method, the selected lactic acid bacteria were found to be belonged to genus Lactobacillus except BD14 identified as Pediococcus pentosaceus. Especially, Lactobacillus pentosus K34 showed the highest resistancy to both of HCl and bile salt, as well as the highest inhibitory activities against S. gallinarum, S. aureus and E. coli. All the selected strains were sensitive to various antibiotics such as neomycin, erythromycin, cephalosporin, amoxicillin/clavulanic acid, ampicillin, oxytetracycline, but resistant to ciprofloxacin. All the selected strains except BL strain were resistant to colistin and streptomycin, and BD14, BD16, K34 strains were resistant to gentamicin.