• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.568-571
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• 1994

Streptmyces fradiae NRRL B1195 and Streptomyces kanamyceticus IFO 13414 are highly resistant to the antibiotics they produce. The ribosomes of these organisms are found to be susceptible to the antibiotics, but the cell free extract of S fradiae is found to contain a phosphotransferase and an acetyltransferase which inactivate kanamycin and neomycin, and that of S. kanamyceticus an acetyltransferse which inactivates kanamycin and neomycin. The resistance of these organisms against streptomycin is found to be due to the resistant ribosomes; actually streptomycin activates their ribosomal systems for the synthesis of polyphenylalanine.

• 한국발생생물학회지:발생과생식
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• 제26권4호
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• pp.145-153
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• 2022

The gut microbiota is involved in the maintenance of physiological homeostasis and is now recognized as a regulator of many diseases. Although germ-free mouse models are the standard for microbiome studies, mice with antibiotic-induced sterile intestines are often chosen as a fast and inexpensive alternative. Pathophysiological changes in the gut microbiome have been demonstrated, but there are no reports so far on how such alterations affect the bacterial composition of the uterus. Here we examined changes in uterine microbiota as a result of gut microbiome disruption in an antibiotics-based sterile-uterus mouse model. Sterility was induced in 6-week-old female mice by administration of a combination of antibiotics, and amplicons of a bacteria marker gene (16S rRNA) were sequenced to decipher bacterial community structures in the uterus. At the phylum-level, Proteobacteria, Firmicutes, and Actinobacteria were found to be dominant, while Ralstonia, Escherichia, and Prauserella were the major genera. Quantitative comparisons of the microbial contents of an antibiotic-fed and a control group revealed that the treatment resulted in the reduction of bacterial population density. Although there was no significant difference in bacterial community structures between the two animal groups, β-diversity analysis showed a converged profile of uterus microbiotain the germ-free model. These findings suggest that the induction of sterility does not result in changes in the levels of specific taxa but in a reduction of individual variations in the mouse uterus microbiota, accompanied by a decrease in overall bacterial population density.

• Archives of Pharmacal Research
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• 제15권3호
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• pp.234-238
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• 1992

Using cell-free extract of Lysobacter lactamgenus, enzymatic conversion of $\delta$-L-($\alpha$-aminoadiphyl)-L-cysteinyl-D-valine (ACV) the first substrate of $\beta$-lactam biosynthesis, into antibiotic compounds was attempted. In high performance liquid chromatographic (HPLC) analysis, the biosynthetic intermediates for cephalosporin antibiotics including isopenicillin N, deacetoxycephalosporin C, deacetylcephalosporin C and unknown cephem compound were detected in reaction mixtures. It implies that cephabacin compounds from L lactamgenus could be produced by biosynthetic routes through penicillin ring formation and its expansion to cephalosporin ring, likely as cephalosporin C from Cephalosporium or cephamycin C from Streptomyces. Among biosynthetic enzyme in cell-free extract, the ring formation activity (isopenicillin N synthetase activity) was separated in 50-60% of ammonium sulfate fraction, and ring expansion activity (deacetoxycephalosporin C synthetase activity) was found to be in 40-50% fraction. The partially purified isopenicillin N synthetase could convert as much as 90% ACV to isopenicillin N during 6-hour reaction.

• Molecules and Cells
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• 제20권1호
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• pp.1-16
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• 2005

The peptidyl transferase center (PTC) is located in a protein free environment, thus confirming that the ribosome is a ribozyme. This arched void has dimensions suitable for accommodating the 3'ends of the A-and the P-site tRNAs, and is situated within a universal sizable symmetry-related region that connects all ribosomal functional centers involved in amino-acid polymerization. The linkage between the elaborate PTC architecture and the A-site tRNA position revealed that the A-to P-site passage of the tRNA 3'end is performed by a rotatory motion, which leads to stereochemistry suitable for peptide bond formation and for substrate mediated catalysis, thus suggesting that the PTC evolved by genefusion. Adjacent to the PTC is the entrance of the protein exit tunnel, shown to play active roles in sequence-specific gating of nascent chains and in responding to cellular signals. This tunnel also provides a site that may be exploited for local co-translational folding and seems to assist in nascent chain trafficking into the hydrophobic space formed by the first bacterial chaperone, the trigger factor. Many antibiotics target ribosomes. Although the ribosome is highly conserved, subtle sequence and/or conformational variations enable drug selectivity, thus facilitating clinical usage. Comparisons of high-resolution structures of complexes of antibiotics bound to ribosomes from eubacteria resembling pathogens, to an archaeon that shares properties with eukaryotes and to its mutant that allows antibiotics binding, demonstrated the unambiguous difference between mere binding and therapeutical effectiveness. The observed variability in antibiotics inhibitory modes, accompanied by the elucidation of the structural basis to antibiotics mechanism justifies expectations for structural based improved properties of existing compounds as well as for the development of novel drugs.

• 한국가금학회지
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• 제36권3호
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• pp.223-229
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• 2009

본 연구는 항생제 사용 유무가 계육 품질 등급에 미치는 영향을 조사하기 위하여 전체 340육계농가(항생제사용 농가 305개소와 무항생제 농가35개소)를 대상으로 전체 10,420,792수 중 1농가 당 100수씩을 무작위로 선별하여 총 34,000수에 대한 등급 판정 결과를 활용하였다. 연구 결과 항생제 사용 유무에 따른 육계의 일당 증체량은 차이를 보이지 않았으나, 품질 A 등급 출현율은 항생제 사용 농가에서 출하된 계육(78.87%)이 무항생제 농가(73.46%)에 비해 높게 나타남이 확인되었다(P<0.05). 이러한 결과를 보인 이유는 품질 A 등급을 받기 위해 판정되는 경제적 및 비경제적 도체 결함의 발생 빈도가 무항생제 농가에서 출하된 계육이 항생제 사용농가에 비해 높게 나타났기 때문이며, 특히 도체 결함과 품질 A 등급과의 상관관계 분석에서 가장 높은 부(-)의 상관관계를 보인 외관 결함의 발생이 무항생제 농가에서 출하된 계육에서 항생제 사용 농가에 비하여 약 1.8배 높음이 확인 되었다. 본 연구결과 무항생제 농가는 항생제 사용 농가에 비해 높은 품질 등급의 계육 생산이 더 어려운 것으로 사료되며, 무항생제 계육 생산의 확대를 위해서는 국가적 차원에서 사양기술 수준의 향상, 천연 항생제 대체 물질의 개발과 함께 가격 차등에 따른 적절한 경제적 보상도 함께 이루어져야 할 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1635-1641
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• 2008

This study investigated the effects of solid-state fermentation of a compound pig feed on its microbial and nutritional characteristics as well as on pig performance and nutrient digestibility. A mixed culture containing Lactobacillus fermentum, Saccharomyces cerevisae and Bacillus subtilis was used for solid-state fermentation and solid-state fermented feed samples were collected on days 0, 1, 2, 3, 5, 7, 10, 15, 20 and 30 for microbial counts and chemical analysis. Lactic acid bacteria increased rapidly during the first three days of fermentation and then slowly declined until day 10 and, thereafter, the counts were maintained at about 6.7 log cfu/g for the duration of the fermentation period. Enterobacteria also increased during the first two days, and then fell below the detectable level of the analysis (3.0 log cfu/g). The pH of the fermentation substrate declined from 6.1 at the start of fermentation to 5.7 by day 30. The water-soluble protein content increased from 8.2 to 9.2% while the concentration of acetic acid increased from 16.6 to 51.3 mmol/kg over the 30-day fermentation. At the end of the 30-day fermentation, the solid-state fermented feed was used in a pig feeding trial to determine its effects on performance and nutrient digestibility in growing-finishing pigs. Twenty crossbred barrows ($14.11{\pm}0.77kg\;BW$) were allotted into two dietary treatments, which comprised a regular dry diet containing antibiotics and a solid-state fermented feed based diet, free of antibiotics. There was no difference due to diet on pig performance or nutrient digestibility. In conclusion, solid-state fermentation resulted in high counts of lactic acid bacteria and low counts of enterobacteria in the substrate. Moreover, feeding a diet containing solid-state fermented feed, free of antibiotics, can result in similar performance and nutrient digestibility in growing-finishing pigs to a regular diet with antibiotics.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1152-1155
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• 2010

In order to establish an axenic (bacteria-free) culture of Microcystis aeruginosa NIER 10039 isolated from a Korean reservoir, the culture was subjected to sequential treatment, including ultrasonication, washing, and addition of antibiotics. Three broad-spectrum antibiotics, namely, kanamycin, ampicillin, and imipenem, were applied separately in that order. Axenicity of the culture was confirmed by cultivation on bacterial media and observation under epifluorescence and scanning electron microscopes. We are the first to establish an axenic culture of a Microcystis strain isolated from Korean reservoirs and can be used in physiological and molecular studies to control toxic Microcystis blooms.

• 미생물학회지
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• 제5권2호
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• pp.97-101
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• 1967

Up to the present time, there are only three methods by which we can obtain bacteria free crown gall tissue. According to some papers related to this field, the first method is based on the works of Braun(53') who maintained infected plants at 46-47'c for several days. But the method has a problem that very few plants can tolerate this temperature. The second method is based on the well known observation that old tumors appear to be bacteria free at least 1 or 2% of the explants. Also this method is known to us as laborious and time consuming. The third method is the one we were using that was attempting to kill the bacteria with bacteriacidal agent such as Antibiotics. In fact., it is reported that almost complete control of crown gall of tomato was obtained by Blanchard('51) when plants were grown in a nutrient containing Aureomycin(20${\mu}g$/ml) following needle puncture with the gall bacteria. We have been engaged in making the experiment by applying solution of Penicillin, Streptomycin and of Chloramphenicol(Succinate free) to find the strong bacteriacidal agent through the method of disc plate, and to confirm the effect of antimicrobial action through the method of plant tissue culture system without possible injury to the host plant. The result of this report is the fact the strongest bacteriacidal agent among the above three Antibiotics was Chloramphenicol(Succinate free 1000 p.p.m). and that there happened no injury to the tissue cultures in a White's 10X media containing 1000 p.p.m. of Chloramphenicol.

• 한국유기농업학회지
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• 제25권4호
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• pp.821-830
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• 2017

본 연구는 10종 허브 추출물에 대한 DPPH 자유라디칼 소거능, 항균효과 및 세포독성에 미치는 영향을 조사함으로써 항생제 대체제로서 활용 가능성을 위한 기초 자료로 제시하고자 수행하였다. 10종의 허브 추출물의 DPPH 자유라디칼 소거능은 로즈마리, 오레가노 및 캐모마일이 각 49.9, 48.9, 47.7%으로 유의적으로 가장 높았다. 허브 추출물의 E. coli K99와 S. typhimurium에 대한 항균활성은 베르가못, 오레가노, 타임과 로즈마리가 두 균주에 공통적으로 활성이 높게 측정되었으며, 활성이 나타나는 농도에서의 세포독성이 비교적 낮아 안전한 것으로 관찰되었다. 본 연구 결과 유기 축산을 위한 가축 내 천연 항생제 대체제로 항균 및 항산화 활성이 높고, 세포독성이 낮게 나타난 오레가노와 로즈마리가 천연물질로 활용 가능할 것으로 판단되며, 다양한 추출 조건으로 최적 추출 효율을 검토하여 추가적인 생리활성물질 검정과 해당 물질에 대한 연구가 필요하다.

• 수산해양교육연구
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• 제25권4호
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• pp.828-835
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• 2013

Products from aquaculture have sometimes been focused on the problems caused by the contamination of chemical agents as the use of chemical agents in aquaculture has been annually increased. The risk of contamination of products by chemical agents is greater in freshwater than in seawater. In order to evaluate the food safety of a fish grown in freshwater, we investigated the residues of antibiotics (tetracycline, oxolinic acid and ciplofloxacin) and malachite green in cultured rainbow trout, Oncorhynchus mykiss. Malachite green, which was prohibited in the application of aquaculture, was not detected in samples tested in this study. The residual content of tetracycline was determined to be less than the permissible amount, <0.2 mg/kg. The contents of ciplofloxacin was also less than the permissible amount, <0.1 mg/kg. However, in case of oxolinic acid, one of samples was only exhibited higher content than the permissible amount (<0.1 mg/kg). The results obtained in this study suggested that the control and regulation of chemical agents such as antibiotics was important to maintain a safe and worry-free seafood supply.