• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.858-864
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• 2007

This study investigated the antibacterial activities of sophoraflavanone G from Sophora flavescens in combination with two antimicrobial agents against oral bacteria. The combined effect of sophoraflavanone G and the antimicrobial agents was evaluated using the checkerboard method to obtain a fractional inhibitory concentration(FIC) index. The sophoraflavanone G+ampicillin(AM) combination was found to have a synergistic effect against S. mutans, S. sanguinis, S. sobrinus, S. gordonii, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis, whereas the sophoraflavanone G+gentamicin(GM) combination had a synergistic effect against S. sanguinis, S. criceti, S. anginosus, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis. Neither combination exhibited any antagonistic interactions(FIC index>4). In particular, the MICs/MBCs for all the bacteria were reduced to one-half$\sim$one-sixteenth as a result of the drug combinations. A synergistic interaction was also confirmed by time-kill studies for nine bacteria where the checkerboard suggested synergy. Thus, a strong bactericidal effect was exerted through the drug combinations, plus in vitro data suggested that sophoraflavanone G combined with other antibiotics may be microbiologically beneficial rather than antagonistic.

• 생명과학회지
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• 제25권1호
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• pp.29-36
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• 2015

천연의 붉은 색소인 prodigiosin은 Serratia marcescens에 의해서 생산되며 이는 pyrrolylpyrromethane 골격으로 구성되어 있다. 이 색소는 그 분자가 가진 특성 때문에 넓은 범위에서 활용되고 있다. 또한 항암제, 면역억제제, 항진균제, 살조제 등 다양한 분야의 효과가 보고되소 있다. Methicillin-resistant Staphylococcus aureus (MRSA)는 세계적으로 가장 주요한 원내 감염균으로써, 미국에서 해마다 HIV로 사망하는 수보다 더 많은 사망률을 보이고 있다. 그러므로 MRSA에 대한 새로운 치료제의 개발이 매우 중요하며 급박한 문제이다. 본 연구에서는 중증오염도를 가진 하천수로부터 Serratia sp. PDGS 120915를 분리하였으며 항 MRSA 활성을 가진 prodigiosin에 대하여 연구하였다. 본 연구를 위하여 HPLC를 이용하여 물질을 정제하였으며, 분리된 물질의 항 MRSA 활성을 확인하였다. Prodigiosin의 MRSA에 대한 최소억제농도(Minimal inhibitory concentration; MIC)는 $32{\mu}g/ml$이었으며, 분할저해농도(Fractional inhibitory concentration; FIC)는 ampicillin과 penicillin에서 상승작용이 있는 것으로 나타났다.

• 한국어병학회지
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• 제13권1호
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• pp.45-51
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• 2000

최근 육상의 넙치 양식장에서는 두 가지의 서로 다른 특성을 가지는 세균성질병이 같이 감염되는 혼합감염증이 빈번하게 발생하고 있는데, 혼합감염증은 서로 다른 원인균의 특성 때문에 단일 종류의 약제만으로는 치료효과를 거두기가 어려운 실정이다. 그러므로 본 연구는 약제의 병용 투여에 의해 이들의 상승작용을 이용함으로써 합병증에 대한 치료효과를 높이기 위한 기초자료를 얻고자 실시하였다. 어류 세균성질병의 원인세균인 Vibrio anguillarum, Edwardsiella tarda, Streptococcus sp., Staphylococcus epidermidis을 선정하여 병용 항균제의 시험관내 활성을 평가하는 대표적 방법인 Checkerboard법을 적용하여 fractional inhibitory concentration (FIC)지수를 구하여 상승효과를 나타내는 병용 항균제를 찾아내었다. (OTC+LM), (TC+FF), (OTC+FF)의 병용 항균제는 V. anguillarum에 대하여, (SNF+FF), (TC+FF), (SNF+OXA), (OTC+FF)의 병용 항균제는 E. tarda에 대하여, (CFX+OL), (OTC+OL), (TC+OL), (OTC+LM), (OTC+SPM), (OTC+EM), (DOXY+OL), (TC+SPM)의 병용 항균제는 Streptococcus sp.에 대하여, (CFX+EM), (FF+EM), (DOXY+OL), (CFX+OL)의 병용 항균제는 S. epidermidis에 대하여 시험관내 상승적 상호작용을 나타내었다.

• Natural Product Sciences
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• 제11권3호
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• pp.160-164
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• 2005

The effects of Cymbopogon citratus essential oil (Lemongrass oil) and its main component, citral (84.30%), on antibiotic-susceptible and -resistant strains of Salmonella enteritidis and S. typhimurium were assessed. C. citratus oil and citral significantly inhibited all strains of the two Salmonella species examined, with minimum inhibiting concentrations (MICs) ranging from 0.5 mg/ml to 8.0 mg/ml. The combined effects of C. citratus oil and citral (84.30%) were evaluated using a checkerboard microtiter assay. Essential oil fractions of C. citratus and citral exhibited strong synergistic or additive effects with streptomycin or kanamycin against S. typhimurium strains with fractional inhibitory concentration (FIC) indices in the range of 0.28 to 1.00. In conclusion, a combination of streptomycin and lemongrass oil or its main component, citral, may be useful for reducing the minimum effective dose of antibiotic required for the treatment of resistant S. typhimurium infections.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3122-3127
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• 2007

Water resource can be examined using biological sensors. Algae has been one of the biological sensors used to evaluate and monitor the water pollution. The monitoring system, however, could determine whether the examined water was safe or not. It needs additional expensive chemical test to figure out the cause of the water pollution. In this study, an endeavor is given to identify the toxicant in the water using the shape of the chlorophyll fluorescence induction curve(FIC) from algae using monitoring system. Fundamental curves are obtained from the experiments with specified amount of toxicant. Baysian method is utilized to determine the unknown toxicant in the water by comparing it with the fundamental curves. The results shows that the proposed method works fairly well.

• 한국연초학회지
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• 제18권1호
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• pp.60-65
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• 1996

Chemicals including antibiotics and bactericides were screened for suppression of streptomycin-resistant Erwinia cmutouom subsp. cmutovom (Ecc) strains in laboratory and field conditions. Oxytetracycline, ethoquinolac and dichlorophen suppressed the growth of streptomycin-resistant Ecc strains in vitro. Fractional inhibitory concentration (FIC) indices of oxytetracycline and ethoquinolac mixed with streptomycin against the Ecc strains were equal to and less than one, respectively. Consequently the efficacy of those chemicals in mixture with sorptomycin were non-antagonistic But that of dichlorophen mixed with streptomycin was more than one, therefore the efficacy of the mixture was antagonistic. Spray of oxyteoucycline, ethoquinolac and agrimycin-100 on the topped burley tobacco plants was efficacious in reducing tobacco hollow stalk at the same level of sorptomycin treatment in three-year field trials, which suggests that those are promising chemicals to be alternative to streptomycin for control of tobacco hollow stalk.

• 한국통신학회논문지
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• 제31권11B호
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• pp.953-959
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• 2006

This paper provides optimum TCP/IP packet size that maximizes the throughput efficiency of ATM layer as a function of TCP/IP packet length for several values of channel BER over wireless ATM LAN links applying data link error control schemes to reduce error problems encountered in using wireless links. For TCP/IP delay-insensitive traffc requiring reliable delivery, it is necessary to adopt data link layer ARQ protocol. So ARQ error control schemes considered in this paper include GBN ARQ, SR ARQ and type-I Hybrid ARQ, which ARQ is needed, but FEC can be used to reduce the number of retransmissions. Especially adaptive type-I Hybrid ARQ scheme is necessary for a variable channel condition to make the physical layer as SONET-like as possible.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2014년도 하계학술대회
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• pp.84-86
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• 2014

국내에서는 지상파 디지털 모바일 방송 표준을 T-DMB(Terrestrial-Digital Multimedia Broadcasting)로 채택하여 상용화 하였다. 현재 재난 발생 시 T-DMB 시스템에서는 Fast Information Channel(FIC)를 이용한 재난 경보 방송을 방송 영역의 가입자들에게 동시에 전달한다. 하지만 일본의 대지진과 같은 긴급한 상황에서 가입자가 재난 경보의 수신을 실패할 때는 큰 피해를 입을 수 있다. 본 논문에서는 기존의 DMB와 재난정보의 다중 전송 기법을 이용하여 가입자의 수신 효율을 높일 수 있는 방법을 제시 한다.

• 상하수도학회지
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• 제22권1호
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• pp.73-78
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• 2008

Water resource can be examined using biological sensors. Algae has been one of the biological sensors used to evaluate and to monitor the water pollution. The monitoring system, however, has not been used to determine what kind of the toxicological substance is in the water. It needs additional expensive chemical test to figure out the cause of the water pollution. In this study, an endeavor is made to identify the toxicant in the water using the shape of the chlorophyll fluorescence induction curve(FIC) from algae using monitoring system. Fundamental curves are obtained from the experiments with specified amount of toxicant. Baysian method is utilized to determine the unknown toxicant in the water by comparing it with the fundamental curves. The results shows that the proposed method works fairly well.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.203-203
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• 2006

In this study, a novel strategy to prepare a crystallized sample of terpolymer containing high content of ${\gamma}-form$ was experimentally sought. By the foaming process, it was possible for the first time to produce a commercial high molar-mass terpolymer being in a high content of ${\Box}-form$. The large amount of nuclei produced during the foaming process by FIC is ascribed to be the reason. It accounts for the structural disorder in the crystallite formation because of excess amount of chains length for the formation of a stable crystallite.