• Journal of Aquaculture
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• v.14 no.3
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• pp.157-163
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• 2001

The antibacterial effect of fish diet soaked in the extract of Salvia miltiorriza was tested to determine its levels of antibacterial activity, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC). The extract showed strong activity against gram positive bacteria, but was weak against gram negative bacteria. Concentration levels of 13.4~40.3 and 67.2~403.0 $\mu\textrm{g}$/ml were determined as the MIC and MBC, respectively. However, levels above 403.0 $\mu\textrm{g}$/ml was neither bacteriostatic nor bactericidal against Edwardsiella tarta, a gram negative strain. The fish diet, soaked in the extract of Salvia miltiorriza, inhibited the growth of all strains of Streptococcus genus and Vibrio anguillarum. The relationship formula between weight of fish diet and Salvia miltiorriza extract absorbed into the fish diet was Y＝2.4953X＋3.3276 ($R^2$= 0.9999). The antibacterial activity of the fish diet, soaked in the extract, was stable from 10 to 35$^{\circ}C$ during the storage period of 28 days.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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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.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1055-1059
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• 2001

Porous glass ceramics composed of Li$_2$O.-Ti $O_2$-P$_2$ $O_{5}$ -CaO were prepared by melting and 2 step heat treatment for nucleation at 61$0^{\circ}C$ and crystallization at 78$0^{\circ}C$. subsequently $\beta$-Ca$_3$(P $O_4$)$_2$crystal phase was selectively leached out in 1N-HC1 solution for 3 days, leaving Li $Ti_2$(P $O_4$)$_3$crystal phases. prepared porous glass ceramics were immersed in 1M AgN $O_3$solution for ion exchange. Staphylococcus aureus and salmonella typhi were used in this study. It was found taht the resultant porous glas ceramics show excellent bacteriostatic properties.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1324-1329
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• 2012

Phosphomannomutase (ManB) is involved in the biosynthesis of GDP-mannose, which is vital for numerous processes such as synthesis of carbohydrates, production of alginates and ascorbic acid, and post-translational modification of proteins. Here, we discovered that a deletion mutant of manB (BG101) in Streptomyces coelicolor (S. coelicolor) showed higher sensitivity to bacteriostatic chloramphenicol (CM) than the wild-type strain (M145), along with decreased production of CM metabolites. Deletion of manB also decreased the mRNA expression level of drug efflux pumps (i.e., cmlR1 and cmlR2) in S. coelicolor, resulting in increased sensitivity to CM. This is the first report on changes in antibiotic sensitivity to CM by deletion of one glycolysis-related enzyme in S. coelicolor, and the results suggest different approaches for studying the antibiotic-resistant mechanism and its regulation.

• The Plant Pathology Journal
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• v.35 no.3
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• pp.234-242
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• 2019

Thirty-four strains of bacteria were isolated from Phellodendron amurense. Using Nectria haematococca as an indicator strain, the best strain, B18, was obtained by the growth rate method. The morphological, physiological and biochemical characteristics of strain B18 and its 16S DNA gene sequence were identified, and the biocontrol effect of strain B18 was assessed in pot and field tests, as well as in a field-control test. Drilling methods were used to determine the antibacterial activity of metabolites from strain B18 and their effects on the growth of pathogen mycelia and spores. The best bacteriostatic rate was 85.4%. B18 can hydrolyse starch and oxidize glucose but does not produce gas; a positive result was obtained in a gelatine liquefaction test. According to 16S DNA gene sequencing, strain B18 is Bacillus methylotrophicus (GenBank accession number: MG457759). The results of pot and field-control trials showed 98% disease control when inoculating $10^8cfu/ml$ of the strain. The disease control effect of the B18 culture liquid (concentrations of $10^8$, $2{\times}10^6$, $10^6$, $5{\times}10^5$ and $2.5{\times}10^5cfu/ml$) in the field-control test was higher than 80%, and the cure rate of the original delivery solution was 96%. Therefore, in the practical forestry production, a $2.5{\times}10^5cfu/ml$ culture liquidshould be applied in advance to achieve good control effects.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1234-1244
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• 2022

Oral streptococci are considered as an opportunistic pathogen associated with initiation and progression of various oral diseases. However, since the currently-available treatments often accompany adverse effects, alternative strategy is demanded to control streptococci. In the current study, we investigated whether short-chain fatty acids (SCFAs), including sodium acetate (NaA), sodium propionate (NaP), and sodium butyrate (NaB), can inhibit the growth of oral streptococci. Among the tested SCFAs, NaP most potently inhibited the growth of laboratory and clinically isolated strains of Streptococcus gordonii under anaerobic culture conditions. However, the growth inhibitory effect of NaP on six different species of other oral streptococci was different depending on their culture conditions. Metabolic changes such as alteration of methionine biosynthesis can affect bacterial growth. Indeed, NaP enhanced intracellular methionine levels of oral streptococci as well as the mRNA expression level of methionine biosynthesis-related genes. Collectively, these results suggest that NaP has an inhibitory effect on the growth of oral streptococci, which might be due to alteration of methionine biosynthesis. Thus, NaP can be used an effective bacteriostatic agent for the prevention of oral infectious diseases caused by oral streptococci.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.550-555
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• 1997

Vibrio cholerae non-O1 (V. cholerae non-O1) was previously called nonagglutinable or noncholera vibrios, since it fails to react with polyvalent O1 antisera. This organism is biochemically and genetically indistinguishable from V. cholerae O1 except serological difference. V. cholerae non-O1 strains are often detected in the environment including bays, estuaries, and fresh water, and also found in food. Therefore it is designated food borne bacterium in Japan. However, research papers on V. cholerae non-O1 are very rare in Korea. In order to investigate bacteriological characteristics of V. cholerae non-O1, we isolated V. cholerae non-O1 from the environmental sea water. Among the isolated V. cholerae non-O1 strains, we selected the strain which had the most strong hemolytic activity, named as V. cholerae non-O1 FM-3. The optimum growth conditions of V. cholerae non-O1 FM-3 were $37^{\circ}C$ and pH 8.5 in BHI broth (containing $0.5\%$ sodium chloride), and it grew better than V. cholerae non-O1 ATCC 25872. But both were not able to grow in BHI broth added $5.0\%$ of sodium chloride or adjusted to pH 5.0. According to the experimental results on the susceptibility test against various antibiotics, there were no significant differences between the isolated strain and reference strain (V. cholerae non-O1 ATCC 25872). Most of the antibiotics examined had bacteriostatic action against V. cholerae non-O1 FM-3 while vancomycin, oxacillin, colistin, polymyxin B, and sulfadiazine had no bacteriostatic activity.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2197-2204
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• 2000

Lignin is a major component of wastewater generated in the chemical processing of wood. Because it is recalcitrant, it inhibits biological treatment of wastewater of pulp manufacturing, especially high concentration of lignin may inhibit the anaerobic digestion. The objective of this study was to evaluate the toxicity of high molecular hardwood lignin (lignosulfonate, MW $\geq$ 20,000) on aceticlastic methanogens in the batch reactors at different temperatures with different sludge concentrations, using anaerobic serum bottles. The hardwood lignin was found to inhibit anaerobic conversion of acetate to methane and carbon dioxide, shown with a long lag-phase before methanogenesis started. The methanogens assumed not to be able to acclimate to the lignin were found to be acclimated slowly in the batch experiments, finally reaching non-toxic levels in which methane production could start. The hardwood lignin was found not to be bacteriocidal but bacteriostatic to aceticlastic methanogens. Hardwood lignin(lignosulfonate) at 1.3, 2.6, and 3.9%(w/w) inhibited the acetateutilizing methanogens of anaerobic digester sludge by 14.5, 17.8, 21.1 days(in noninhibitory condition it took 10 days) to produce the same amount of methane. The inhibitory effect of lignin was examined at temperature ranges of $30^{\circ}C$ to $50^{\circ}C$. When 2.6% of lignin was contained in wastewater, methane production was highest at $30^{\circ}C$ during initial 8 days. At $4^{\circ}C$, methane production rapidly increased after 12 days of digestion, the value became higher than that at $30^{\circ}C$ after 14 days. However, the methane production was completely inhibited during whole digestion period at $50^{\circ}C$. High ratio of lignin concentration to initial anaerobic sludge concentration gave tolerance to the inhibition. In this experiment, high molecular hardwood lignin was not degraded and decolorized.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.1-14
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• 2005

The maintenance of good oral health in adults is often hindered by oral malodor and periodontal diseases which are known to be commonly caused by some species of Gram-negative anaerobic bacteria, with low sensitivity to common synthetic antibiotics or antibacterial chemical agents. Therefore the development of a nonharmful natural antibacterial oral rinsing remedy against the causative bacteria is thought to be very important. The purpose of this study is to obtain the basic data for development of a nonharmful natural antibacterial oral rinsing remedy using colloidal silver. The author applied colloidal silver solution with concentration of 10, 30, 50, 80 ppm to some strains in species of Prevotella intermedia, Porphyromonas gingivalis, Fusobaterium nucleatum, and evaluated the effects of colloidal silver on the growth of experimental bacterial strains in aspects of minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and growth pattern after incubation for 24, 48, 72 hours. The obtained results were as follows: MIC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 10 or 30 ppm in P. gingivalis, and 30, 50, or 80 ppm in F. nucleatum. And MBC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 30 or 50 ppm in P. gingivalis, 30 or 80 ppm in F. nucleatum. Therefore it was concluded that colloidal silver exhibited bacteriostatic or/and bacteriocidal effects against some experimental strain. And the inhibition of growth of experimental strains were markedly or considerably exhibited under 30 ppm$\sim$50 ppm of colloidal silver solution for 48 hours$\sim$72 hours in P. intermedia, 10 ppm$\sim$30 ppm for 24 hours$\sim$48 hours in P. gingivalis, 30 ppm for 24 hours in F. nucleatum. These results indicate that the colloidal silver inhibited effectively the growth of some species of Gram-negative anaerobic bacteria by exhibition of bacteriostatic or/and bacteriocidal effects, and can be used as a possible major ingredient of the nonharmful natural antibacterial oral rinsing remedy to oral malodor and periodontal diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.83-88
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• 2004

The purpose of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Large unilamellar vesicles (OPGTL) were prepared with total lipids extracted from cultured Porphyromonas gingivalis outer membranes (OPG). The anthroyloxy probes were located at a graded series of depths inside a membrane, depending on its substitution position (n) in the aliphatic chain. Fluorescence polarization of n-(9-anthroyloxy)stearic acid was used to examine effects of chlorhexidine digluconate on differential rotational mobility, while changing the probes' substitution position (n) in the membrane phospholipids aliphatic chain. Magnitude of the rotational mobility of the intact six membrane components differed depending on the substitution position in the descending order of 16-(9-anthroyloxy)palmitic acid (16-AP), 12, 9, 6, 3 and 2-(9-anthroyloxy)stearic acid (12-AS, 9-AS, 6-AS, 3-AS and 2-AS). Chlorhexidine digluconate increased in a dose-dependent manner the rate of rotational mobility of hydrocarbon interior of the OPGTL prepared with total lipids extracted from cultured OPG, but decreased the mobility of membrane interface of the OPGTL. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.