• KSBB Journal
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• 제24권3호
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• pp.279-286
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• 2009

방선균은 다양한 생리활성 물질을 이차대사산물로 생산하는 산업적으로 매우 유용한 미생물이다. 이에 따라 많은 연구진들이 방선균에 대한 분자생물학적 연구와 산업적 이용에 대한 연구들을 수행하고 있다. 방선균 중에서도 S. avermitilis는 강력한 구충효과가 있는 avermectin을 생산하지만, 또한 포유동물 세포의 미토콘드리아에서 산화적 인산화반응을 억제하는 oligomycin도 함께 생성된다. 따라서 S. avermitilis에서 oligomycin의 생성을 제거시키기 위하여 oligomycin synthetase gene을 disruption 시키기 위한 연구를 수행하였다. 이를 위하여 S. avermitilis로부터 cloning 한 oligomycin synthetase gene (olmA5)의 중앙부분에 apramycin resistance gene을 끼워 넣어 integration vector로 구축한 후에 S. avermitilis의 chromosomal DNA와의 homologous recombination에 의하여 olmA5 gene의 disruption을 유도하였다. Disruption mutants (olmA5::apra)는 PCR을 통해 olmA5 gene의 위치에 apramycin resistance gene이 존재하는 것으로 확인하였고, 또한 HPLC 분석을 통해 oligomycin 생합성이 완전히 제거된 것임을 확인하였다. 그러나 disruption mutant (olmA5::apra)를 이용하여 avermectin 만을 생산할 수 있었으나, avermectin의 생산량에는 거의 변화가 없었다. 이러한 mutants는 산업적으로 avermectin을 생산하기 위한 균주 개량의 훌륭한 source가 될 수 있을 것이다.

• Parasites, Hosts and Diseases
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• 제58권1호
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• pp.7-14
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• 2020

Toxoplasma gondii is an intracellular protozoan parasite that infects approximately one third of the human population worldwide. Considering the toxicity and side effects of anti-toxoplasma medications, it is important to develop effective drug alternatives with fewer and less severe off-target effects. In this study, we found that 4-hydroxybenzaldehyde (4-HBA) induced autophagy and the expression of NAD-dependent protein deacetylase sirtuin-1 (SIRT1) in primary murine bone marrow-derived macrophages (BMDMs). Interestingly, treatment of BMDMs with 4-HBA significantly reduced the number of macrophages infected with T. gondii and the proliferation of T. gondii in infected cells. This effect was impaired by pretreating the macrophages with 3-methyladenine or wortmannin (selective autophagy inhibitors) or with sirtinol or EX527 (SIRT1 inhibitors). Moreover, we found that pharmacological inhibition of SIRT1 prevented 4-HBA-mediated expression of LC3-phosphatidylethanolamine conjugate (LC3-II) and the colocalization of T. gondii parasitophorous vacuoles with autophagosomes in BMDMs. These data suggest that 4-HBA promotes antiparasitic host responses by activating SIRT1-mediated autophagy, and 4-HBA might be a promising therapeutic alternative for the treatment of toxoplasmosis.

• 대한화학회지
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• 제55권4호
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• pp.626-632
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• 2011

폭심(phoxim)은 널리 사용되고 있는 구충제인 동물용의약품이다. 본 논문에서는 소와 돼지 근육에 잔류하는 폭심을 분석하기 위해서, 실리카 고체상과 아세토니트릴을 사용하여 추출/정제하였다. 분석을 위해서 LC/ESI-MS/MS 방법이 사용되었다. HPLC에서 $C_{18}$ 컬럼($2.1{\times}100\;mm$, $3.5\;{\mu}m$)이 사용되었으며, 이동상으로는 0.1% formic acid와 물이 사용되었다. 소(0.0048~2.0 mg/kg)와 돼지(0.0055~2.0 mg/kg)에 소량첨가하여 얻은 검정곡선은 좋은 직선성($r^2$=0.995)을 나타내었다. 소와 돼지의 매트릭스에 대해서 0.0048~0.2 mg/kg범위에서 68.2~106.9%의 정확도를 나타내었으며, LOD는 0.0014~0.0017 mg/kg, LOQ는 0.0048~0.0055 mg/kg범위에 있었으며, 11.2%의 상대표준편차를 나타내었다.

• 한국수산과학회지
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• 제54권5호
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• pp.634-643
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• 2021

Han In-jin (Artemisia iwayomogi Kitamura) and Cham Dang-gwi (Angelica gigas Nakai) exhibit antibacterial, antiparasitic, antifungal, and antiviral properties in vitro. In this study, mixture of the extracts of these two medicinal plants was absorbed on pellets. Thereafter, these pellets were fed to olive flounder Paralichthys olivaceus for 12 weeks at laboratory (1^st experiment) and 24 weeks at field test (2^nd experiment), and the immune activity and disease resistance properties of the extracts were examined. It was observed that lysozyme activities of plasma, spleen, and kidney improved after 12 weeks. Furthermore, when the olive flounders were artificially infected with bacterial pathogens, their cumulative mortality decreased in the group that was fed the extracts for 12 weeks compared to that in control group, and the relative percent survival also improved. This study concluded that mixture of Han In-jin and Cham Dang-gwi extracts provides disease resistance in vivo.

• Journal of Veterinary Science
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• 제23권5호
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• pp.64.1-64.9
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• 2022

Background: Fluralaner is a novel drug belonging to the isoxazoline class that acts on external parasites of domestic animals. It is used systemically via drinking water, especially against red poultry mite in layer chickens. Fluralaner is frequently used in layers infected with D. gallinae. However, no study to date has investigated the effects of feed intake and water hardness. Objectives: This study aimed to investigate the effects of variable water hardness and feed intake on the pharmacokinetic profile of fluralaner. Methods: Layer chickens were divided into four groups (n = 8): fed + purified water (Group 1), feed restricted + purified water (Group 2), feed restricted + hard water (Group 3), and feed restricted + soft water (Group 4). After administering a single dose of the drug with drinking water, the blood samples were collected for 21 days. Fluralaner concentrations in plasma samples were determined by liquid chromatography/tandem mass spectrometry. The maximum plasma concentration (C_max), time to reach maximum plasma concentration (t_max), area under the concentration-time curve values (AUC_0-21d), half-life (t_1/2), and other pharmacokinetic parameters were calculated. Results: Although the highest maximum plasma concentration (C_max) was determined in Group 1 (fed + purified water), no statistically significant difference was found in the C_max, t_max, t_1/2, MRT_{0-inf_obs}, Vz/F_obs, and Cl/F_{_obs} parameters between the experimental groups. Conclusions: It was concluded that the feed intake or water hardness did not change the pharmacokinetic profile of fluralaner in layer chickens. Therefore, fluralaner could be used before or after feeding with the varying water hardness in poultry industry.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.405-417
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• 2023

Chagas disease, caused by Trypanosoma cruzi parasite, is a significant but neglected tropical public health issue in Latin America due to the diversity of its genotypes and pathogenic profiles. This complexity is compounded by the adverse effects of current treatments, underscoring the need for new therapeutic options that employ medicinal plant extracts without negative side effects. Our research aimed to evaluate the trypanocidal activity of Bidens pilosa fractions against epimastigote and trypomastigote stages of T. cruzi, specifically targeting the Brener and Nuevo León strains-the latter isolated from Triatoma gerstaeckeri in General Terán, Nuevo León, México. We processed the plant's aerial parts (stems, leaves, and flowers) to obtain a methanolic extract (Bp-mOH) and fractions with varying solvent polarities. These preparations inhibited more than 90% of growth at concentrations as low as 800 ㎍/ml for both parasite stages. The median lethal concentration (LC₅₀) values for the Bp-mOH extract and its fractions were below 500 ㎍/ml. Tests for cytotoxicity using Artemia salina and Vero cells and hemolytic activity assays for the extract and its fractions yielded negative results. The methanol fraction (BPFC3MOH1) exhibited superior inhibitory activity. Its functional groups, identified as phenols, enols, alkaloids, carbohydrates, and proteins, include compounds such as 2-hydroxy-3-methylbenzaldehyde (50.9%), pentadecyl prop-2-enoate (22.1%), and linalool (15.4%). Eight compounds were identified, with a match confirmed by the National Institute of Standards and Technology (NIST-MS) software through mass spectrometry analysis.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권5호
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• pp.284-293
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• 2013

Purpose: For reconstruction of craniomaxillofacial defects caused by tumor, trauma, infection etc, free flap transplantation with microvascular surgery is a very useful method. Thrombus formation at the anastomosis site is the major cause of graft failure. 4-Hexylresorcinol (4-HR) is generally known as an antiseptic and antiparasitic agent. This study was conducted in order to evaluate the effect of 4-HR on blood coagulation in vitro. In addition, we investigated thrombus formation and endothelial repair of an injured vessel in an animal model. Methods: In the in vitro experiment, we compared blood coagulation time between the 4-HR treated group and normal blood. Thirty rats were used for in vivo animal experiments. After exposure of the right femoral vein, a micro vessel clamp was placed and the femoral vein was intentionally cut. Microvascular anastomosis was performed on all rats using 10-0 nylon under microscopy. The animals were divided into two groups. In the experimental group (n=15), 4-HR (250 mg/kg) mixed with olive oil (10 mL/kg) was administered per os daily. Animals in the control group (n=15) were given olive oil only. The animals were sacrificed at three days, seven days, and fourteen days after surgery and rat femoral vein samples were taken. Vascular patency and thrombus formation were investigated just before sacrifice. Histologic analysis was performed under a microscope. Results: Results of an in vitro blood coagulation test showed that coagulation time was delayed in the 4-HR treated group. The results obtained from an in vivo 4-HR administered rat model showed that the patency of all experimental groups was better at thirty minutes, seven days, and fourteen days after microvascular anastomosis than that of the control group at seven and fourteen days after anastomosis, and the amount of thrombus in the experimental groups was much less than that of the control group. Endothelial repair was observed in the histologic analysis. Conclusion: Findings of this study demonstrated that blood coagulation was delayed in the vitro 4-HR treated group. In addition, good vascular patency, anti-thrombotic effect, and repair of venous endothelial cells were observed in the vivo 4-HR administered rat group.

• 한국미생물·생명공학회지
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• 제39권2호
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• pp.104-110
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• 2011

방선균은 그램양성 토양 박테리아로서 항생제, 항암제, 항구충제, 면역억제제 등 유용한 2차 대사산물을 생산하는 유용 산업미생물이다. 비록 대부분의 방선균이 속해있는 스트렙토마이세스는 지난 수 십 년간 분자수준에서의 연구가 집중적으로 진행되어 왔으나, 최근에 분리된 잠재적 유용성을 갖는 스트렙토마이세스 이외의 희소방선균들은 유전자 조작시스템의 부재로 그 특성이 잘 규명되지 않고 있다. 본 연구에서는 독립적으로 분리된 180 여 방선균주들 중에서 희소방선균만을 선별하기 위하여 중합효소연쇄반응을 이용한 유전체 스크리닝 전략을 시도하였으며, 이 전략을 통하여 7종의 희소방선균을 성공적으로 분리하였다. 특히 여러 생리활성 테스트를 통하여, 항진균 및 항생제 활성을 띄는 잠재적 유용성이 높은 노카이디옵시스 균주 MMBL010을 선별하였다. 또한 전통적인 방선균 유전자 조작기법이 작동하지 않는 본 MMBL010 균주를 대장균 접합을 통한 유전자 전달 시스템도 최적화시킴으로써, 유전체 스크리닝을 통한 유용희소방선균의 선별 및 유전자 조작시스템 구축은 궁극적으로 희소방선균의 잠재적 유용성을 극대화시킬 수 있는 효율적인 전략으로 사료된다.

• Parasites, Hosts and Diseases
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• 제52권6호
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• pp.613-619
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• 2014

Neospora caninum (Apicomplexa; Sarcocystidae) is a protozoan that causes abortion in cattle, horses, sheep, and dogs as well as neurological and dermatological diseases in dogs. In the central nervous system of dogs infected with N. caninum, cysts were detected that exhibited gliosis and meningitis. Flavonoids are polyphenolic compounds that exhibit antibacterial, antiparasitic, antifungal, and antiviral properties. In this study, we investigated the effects of flavonoids in a well-established in vitro model of N. caninum infection in glial cell cultures. Glial cells were treated individually with 10 different flavonoids, and a subset of cultures was also infected with the NC-1 strain of N. caninum. All of the flavonoids tested induced an increase in the metabolism of glial cells and many of them increased nitrite levels in cultures infected with NC-1 compared to controls and uninfected cultures. Among the flavonoids tested, 3',4'-dihydroxyflavone, 3',4',5,7-tetrahydroxyflavone (luteolin), and 3,3',4',5,6-pentahydroxyflavone (quercetin), also inhibited parasitophorous vacuole formation. Taken together, our findings show that flavonoids modulate glial cell responses, increase NO secretion, and interfere with N. caninum infection and proliferation.

• 대한수의학회지
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• 제39권2호
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• pp.257-266
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• 1999

Ivermectin is a widely used broad spectrum antiparasitic agent in veterinary medicine. In this work, we examined the pharmacokinetic parameters and the tissue residue profile of a new injectable formulation of ivermectin developed for pigs. The plasma ivermectin levels reached the peak at about 9 and 2 hours after the administrations in young and adult pigs, respectively. But the elimination half-life (3-3.5 days) and the $C_{max}$ values (24~28 ng/ml) were not significantly different between young and adult pig groups. When compared to the reference formulation, the $C_{max}$ of test formulation was higher and $T_{1/2}$ values were shorter than those of the reference formulation, respectively. The tissue residue levels were dose- and time-dependent and were higher in the liver and fat, than in the other tissues such as the injection sites, the kidney, intestine, muscle, plasma (4~74 ng/g) at the 7th day after the administration of both formulations of ivermectin. Then, the mean tissue ivermectin levels at the 21st day after the administration in all the tissues decreased to 7.4 and 25% of the 7th day levels in the test and reference formulations, respectively. In general, the tissue levels of ivermectin in the animals treated with the test formulation decreased more rapidly than those with the reference formulation. The tissue to plasma distribution ratio (T/P ratio) of ivermectin was higher in the liver and fat than other tissues. The T/P ratio in the liver of animals treated with the test formulation was somewhat higher than that in the animals treated with the reference formulation. Taken together, the results of pharmacokinetic and tissue residue studies indicate that the test formulation of ivermectin for subcutaneous injection is comparable to the reference formulation, but unique in that it has higher peak plasma concentrations, shorter elimination half-life and higher T/P ratio in the liver than the reference formulation.