• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.740-744
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• 2003

The antimicrobial substance produced by Lactobacillus bulgaricus was inactivated by pretense, which confirmed it as a bacteriocin and referred to 'bulgaricin HJ'. The bulgaricin HJ showed the inhibitory activity against mastitis pathogens, gram-positive and gram-negative bacteria. The optimal conditions for the production of bulgaricin HJ were at the temperature of $30^{\circ}C$ and 10 h after cultivation of L. bulgaricus. Staph. and Strep. agalactiae, common bovine mastitis pathogens, were treated with bulgaricin HJ by the agar well diffusion method and showed antimirobial activities to the bovine mastitis pathogens. The activity of the bulgaricin HJ was maintained at pH 6-7 and $100^{\circ}C$ for 60 min against the mastitis pathogens. The bulgaricin HJ was determined as class IV bacteriocin by various enzyme treatments. Colony forming units analysis with indicator strains by the treatments of bulgaricin HJ indicates that the mode of bacteriocin action was bactericidal rather than bacteriostatic.

• Journal of Veterinary Science
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• 제22권6호
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• pp.41.1-41.14
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• 2021

Background: Our previously prepared ceftiofur (CEF) hydrochloride oily suspension shows potential wide applications for controlling swine Streptococcus suis infections, while the irrational dose has not been formulated. Objectives: The rational dose regimens of CEF oily suspension against S. suis were systematically studied using a pharmacokinetic-pharmacodynamic model method. Methods: The healthy and infected pigs were intramuscularly administered CEF hydrochloride oily suspension at a single dose of 5 mg/kg, and then the plasma and pulmonary epithelial lining fluid (PELF) were collected at different times. The minimum inhibitory concentration (MIC), minimal bactericidal concentration, mutant prevention concentration (MPC), post-antibiotic effect (PAE), and time-killing curves were determined. Subsequently, the area under the curve by the MIC (AUC_0-24h/MIC) values of desfuroylceftiofur (DFC) in the PELF was obtained by integrating in vivo pharmacokinetic data of the infected pigs and ex vivo pharmacodynamic data using the sigmoid E_max (Hill) equation. The dose was calculated based on the AUC_0-24h/MIC values for bacteriostatic action, bactericidal action, and bacterial elimination. Results: The peak concentration, the area under the concentration-time curve, and the time to peak for PELF's DFC were 24.76 ± 0.92 ㎍/mL, 811.99 ± 54.70 ㎍·h/mL, and 8.00 h in healthy pigs, and 33.04 ± 0.99 ㎍/mL, 735.85 ± 26.20 ㎍·h/mL, and 8.00 h in infected pigs, respectively. The MIC of PELF's DFC against S. suis strain was 0.25 ㎍/mL. There was strong concentration-dependent activity as determined by MPC, PAE, and the time-killing curves. The AUC_0-24h/MIC values of PELF's DFC for bacteriostatic activity, bactericidal activity, and virtual eradication of bacteria were 6.54 h, 9.69 h, and 11.49 h, respectively. Thus, a dosage regimen of 1.94 mg/kg every 72 h could be sufficient to reach bactericidal activity. Conclusions: A rational dosage regimen was recommended, and it could assist in increasing the treatment effectiveness of CEF hydrochloride oily suspension against S. Suis infections.

• Advances in Traditional Medicine
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• 제8권2호
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• pp.171-177
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• 2008

Epigallocatechin 3-gallate (EGCG), one of the major catechins of tea, was isolated from the decaffeinated, crude methanolic extract of Indian green tea (Camellia sinensis L. O. Kuntze) using chromatographic techniques. EGCG was then screened for antidiarrhoeal activity against 30 strains (clinical isolates) of V. cholerae, which is a well known Gram negative bacillus functioning as the pathogen of cholera. V. cholerae strains like V. cholerae 69, 71, 83, 214, 978, 1021, 1315, 1347, 1348, 569B and ATCC 14033 were inhibited by EGCG at a concentration of $25\;{\mu}g/ml$ whereas V. cholerae 10, 522, 976 were even more sensitive, being inhibited at $10\;{\mu}g/ml$ level. However, V. cholerae DN 16, DN 26, 30, 42, 56, 58, 113, 117, 564, 593, 972 and ATCC 14035 were inhibited at $50\;{\mu}g/ml$ level of EGCG. Only four strains were inhibited at $100\;{\mu}g/ml$. In this study the isolated compound was found to be bacteriostatic in its mechanism of action. In the in vivo experiment using the rabbit ileal loop model two different dosages of EGCG ($500\;{\mu}g/ml$ and $1,000\;{\mu}g/ml$) were able to protect the animals when they were challenged with V. cholerae 569B in the ileum.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.229-236
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• 1998

6-Substituted derivatives of 1-［(2-hydroxyethoxy)methyl］-6-(phenylthio)thymine (HEPT) were synthesized by introducing alkyl groups with the aid of chlorotrimethylsilane, and then purified ranging 40 to 81 % of yield. Because of their peculiar structures, we presumed that HEPT derivatives would contain extra biological activities other than their already known anti-human immunodeficiency viral (HIV -1) activities. In this study, we investigated the possible effects of the HEPT derivatives on bacterial growth and found their selective antibiotic activities against gram-positive strains. We could not observe the corresponding activity from a disc-zone test, but confirmed the activity by liquid cultivation. Since the growth rate of cells was easily recovered, the antibiotic function was suggested to be bacteriostatic. We also suggested that the intracellular fate of HEPT derivatives would be fast. A HEPT derivative f-3 was shown to synergize unidirectionally toward chloramphenicol (Chr). With 0.1 mM f-3, the Chr-directed growth-inhibitory curve appeared 4 hours earlier than found without the additive. Interestingly, from the data of SDS-polyacrylamide gel electrophoresis (PAGE), we found that a membrane-bound protein having a molecular weight of 70-kDa was overexpressed by f-3 in S. aureus.

• Advances in Traditional Medicine
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• 제6권2호
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• pp.126-133
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• 2006

The cardiovascular drug nifedipine exhibited significant in vitro and in vivo antibacterial activity against 331 strains of bacteria belonging to three Gram-positive and twelve Gram-negative genera. The minimum inhibitory concentration of the drug, as determined both by agar and broth dilution methods, was seen to range from $25\;-\;200\;{\mu}g/ml$ against most test bacteria, including several pathogenic ones, in the in vitro studies. Nifedipine was bacteriostatic in action. in vivo studies with this drug showed that it could offer statistically significant protection (P < 0.001) to mice challenged with a virulent bacterium. Therefore, nifedipine has the potential of an antibacterial agent, which may be developed after further pharmacological studies.

• 생명과학회지
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• 제28권1호
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• pp.110-115
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• 2018

본 연구는 천연물유래 구강건강소재로써 약용작물의 이용 가능성을 알아보기 위해 수행되었으며 네팔, 라오스, 몽골, 방글라데시, 베트남, 중국 등지에 자생하는 200여 종의 약용작물로부터 추출한 메탄올 추출물 중 인도감나무 줄기 추출물(1 mg/disc)이 P. gingivalis ATCC33277와 S. mutans ATCC25175에 대해 가장 우수한 항균활성을 나타내었으며 양성대조구로 사용한 chlorhexidine, sodium lauryl sulfate, triclosan과 유사한 항균활성을 나타내었다. 인도감나무 줄기 추출물은 P. gingivalis ATCC33277에 비해 S. mutans ATCC25175에 대해 높은 항균활성을 나타내었으며 P. gingivalis ATCC33277에 대해서는 살균작용(MBC, 0.4 mg/ml)을, S. mutans ATCC25175에 대해서는 정균작용을 하는 것으로 확인되었다. 인도감나무 줄기 추출물이 0.2-1.0 mg/ml 농도로 처리된 배양액에서 S. mutans ATCC25175의 바이오필름 생성율과 바이오필름 생성관련 유전자 comX의 발현은 추출물의 농도가 높아질수록 억제되는 것을 확인할 수 있었다. 이상의 결과를 종합하면 인도감나무 줄기 추출물은 치아우식증 원인균인 S. mutans ATCC25175에 대한 정균작용과 바이오필름 생성 억제능이 우수하기 때문에 천연물유래 구강건강소재로써 이용 가능성이 높을 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.115-122
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• 2012

Apidaecin Ib had strong antimicrobial activity against several tested Gram-negative bacteria including Escherichia coli, Enterobacter cloacae, and Shigella flexneri (MECs; $0.3-1.5{\mu}g/mL$), but showed no activity against all the tested Gram-positive bacteria including Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and one yeast, Candida albicans (MECs; > $125{\mu}g/mL$). Interestingly, this peptide showed potent antibacterial activity only against Edwardsiella species (MECs; $0.6-3.6{\mu}g/mL$) among the tested fish pathogenic bacteria through a bacteriostatic process and showed no significant hemolytic activity. Apidaecin Ib took an unordered structure in all environments and also had very weak membrane perturbation activity even at $25{\mu}M$. Anti-Edwardsiella activity of apidaecin Ib is stronger than those of other antimicrobial polypeptides or antibiotics, but its activity is salt-sensitive. These results suggest that apidaecin Ib has Edwardsiella speciesspecific antibacterial activity and could be applied as new preventive or control additives for Edwardsiella species infection in freshwater fish aquaculture.

• 대한가정학회지
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• 제40권11호
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• pp.93-105
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• 2002

Nylon fabrics and stocking were dyed with artemisia dyeing solution, dyed with the natural dyestuffs that were manufactured from chestnut hulls by boiling in 0.5% NaOH solution and powdering in freeze dryer, and dyed with gromwell dyeing solution. Dyeabilities on nylon fabrics and stocking were good because of being amine group. All the dyed fabrics & stocking showed excellent in color fastness to laundering, and as poor as grade 1 to light fastness. But Light fastness of them could be improved to grade 3 or 4-5 by treatment with gallic acid and by repeated dyeing. Antimicrobial activities of the fabrics dyed with artemisia and gromwell against Staphylococcus aureus and Candida albicans were excellent in the aspect of bacteriostatic and fungistatic. There were not any distinct differences between mordant and non-mordant fabrics.

• 한국동물위생학회지
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• 제36권4호
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• pp.297-301
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• 2013

The present study was to investigate anti-microbial effects of curcumin on major bacterial pathogens for farmed fish, such as Aeromonas hydrophila, A. salmonicida subsp. masoucida, A. salmonicida subsp. salmonicida, Edwardsiella tarda, Vibrio vulnificus, V. paraheamolyticus using disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. In disc diffusion test, curcumin exhibited concentration-dependent antimicrobial activities to all bacteria pathogens used in the study. Antimicrobial effects of curcumin was found differently depending on bacterial species when determined by MIC or MBC tests. For examples, E. tarda and A. hydrophila was respectively the most sensitive bacterium for bacteriostatic and bacteriocidal effect of curcumin. Collectively, curcumin could be a potential natural drug for controlling pathogenic bacteria in the aquaculture industry.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.