• Journal of Microbiology
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• v.44 no.3
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• pp.255-262
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• 2006

Titanium and its alloys are technically superior and cost-effective materials, with a wide variety of aerospace, industrial, marine, and commercial applications. In this study, the effects of titanium ions on bacterial growth were evaluated. Six strains of bacteria known to be resistant to both metal ions and antibiotics were used in this study. Two strains, Escherichia coli ATCC 15489, and Pseudomonas aeruginosa ATCC 10145, proved to be resistant to titanium ions. Plasmid-cured p. aeruginosa resulted in the loss of one or move resistance markers, indicating plasmid-encoded resistance. The plasmid profile of p. aeruginosa revealed the presence of a 23-kb plasmid. The plasmid was isolated and transformed into $DH5{\alpha}$. Interestingly, the untransformed $DH5{\alpha}$ did not grow in 300 mg/l titanium ions, but the transformed $DH5{\alpha}$ grew quite well under such conditions. The survival rate of the transformed $DH5{\alpha}$ also increased more than 3-fold compared to that of untransformed $DH5{\alpha}$.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.417-426
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• 2020

Bacillus amyloliquefaciens is an important plant disease-preventing and growth-promoting microorganism. B. amyloliquefaciens WS-8 can stimulate plant growth and has strong antifungal properties. In this study, we sequenced the complete genome of B. amyloliquefaciens WS-8 by Pacific Biosciences RSII (PacBio) Single Molecule Real-Time (SMRT) sequencing. The genome consists of one chromosome (3,929,787 bp) and no additional plasmids. The main bacteriostatic substances were determined by genome, transcriptome, and mass spectrometry data. We thereby laid a theoretical foundation for the utilization of the strain. By genomic analysis, we identified 19 putative biosynthetic gene clusters for secondary metabolites, most of which are potentially involved in the biosynthesis of numerous bioactive metabolites, including difficidin, fengycin, and surfactin. Furthermore, a potential class II lanthipeptide biosynthetic gene cluster and genes that are involved in auxin biosynthesis were found. Through the analysis of transcriptome data, we found that the key bacteriostatic genes, as predicted in the genome, exhibited different levels of mRNA expression. Through metabolite isolation, purification, and exposure experiments, we found that a variety of metabolites of WS-8 exert an inhibitory effect on the necrotrophic fungus Botrytis cinerea, which causes gray mold; by mass spectrometry, we found that the main substances are mainly iturins and fengycins. Therefore, this strain has the potential to be utilized as an antifungal agent in agriculture.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1706-1712
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• 2006

Because of the need for new antimicrobial substances with novel mechanisms of action, we report here the use of an Acinetobacter reporter system for high-throughput screening of active antimicrobial agents. The bioreporter Acinetobacter strain DF4/PUTK2 carrying luciferase genes luxCDABE was chosen because of its ecological importance and it is widespread in nature. This bioreporter is genetically engineered to emit light constitutively that can be measured in real time by luminometry. Hence, this reporter system was employed to determine the bacteriostatic actions of spent-culture supernatants derived from twelve bacterial isolates. Out of the results, the strongest bioluminescence inhibitory effect of the supernatants was recorded with Bacillus cereus strain BAC (S5). Subsequently, ethyl acetate extracts of extracellular products of strain BAC (S5) were separated by a thin-layer chromatography (TLC). Based on the bioluminescence inhibitory assay, three fractions were found to have antimicrobial activity. One fraction (C) having the strongest antimicrobial activity was further purified using TLC and characterized by IR, $^1H$ NMR, mass spectrometry, SDS-PAGE, and amino acid composition analysis. The results predicted the presence of 2-pyrrolidone-S-carboxylic acid (PCA) and the octadeconic-acid-like fatty acid. Fraction C also demonstrated a broad inhibitory activity on several Gram-negative and Gram-positive bacteria. In conclusion, the Acinetobacter reporter system shows great potential to be a reliable, sensitive, and real-time indicator of the bacteriostatic actions of the antimicrobial agents.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.73-78
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• 1982

The optimal conditions of sterilization for Streptococcus pyogenes treated with disinfectant and antibiotics were investigated. The survivors of Streptococcus pyogenes had no effect at the concentration of 0.2% hydrogen peroxide but decreased abruptly when the concentration increased from 0.4% to 1.0% Minimum inhibitory concentration values of 0.78, 0.39 and 3.125 $\mu\textrm{g}$/$m\ell$ for erythromycin, tetracycline and cephalexin, respectively, were obtained for Streptococcus pyogenes when incubated at 37 $^{\circ}C$ for 24 hrs. Tetracycline and cephalexin showed bactericidal effect against Streptococcus pyogenes, whereas erythromycin did bacteriostatic effect.

• Journal of Food Hygiene and Safety
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• v.10 no.1
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• pp.23-28
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• 1995

The effect of the ethanol extract from salviae miltiorrhizae radix (Salvia miltiorrhiza) on the microbial growht and the stability of the extracted antimicrobial material were investigated. The ethanol extract had strong growth inhibition activity (MIC, 3.13~50.0 $\mu\textrm{g}$/ml) against Gram-positive bacteria such as B. subtilis, L. monocytogenes and S. aureus. Among Gram-positive bacteria tested, B. subtilis was the most susceptible to the extracted substance. While the antimicrobial activity of the ethanol extract was weak (MIC, 400~800 $\mu\textrm{g}$/ml) to E. coli and yeasts (C. albicans, Sacch. diastaticus). The ethanol extract had bactericidal action at higher concentration than MIC against B. subtilis, while the extract had only bacteriostatic action against S. aureus. The extracted antimicrobial substance was stable in the pH range of 4.0 to 10.0, heat treatment at 121$^{\circ}C$ for 15 min, and freezing and thawing

• Journal of Microbiology
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• v.42 no.1
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• pp.47-50
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• 2004

There are a number of studies that explain the metabolism and roles of metallic titanium and titanium-ion. One of the most intriguing results from these studies is the finding of metallic titanium having no bacteriostatic effects on oral bacterial species. In this research, the effects of titanium-ion on the growth of twenty-two bacterial species, some of which are commonly found in foods such as yoghurt, kimchi, and soy fermented products, were investigated. All but two bacteria, Escherichia coli and Pseudomonas aeruginosa appeared to be sensitive to titanium-ion. These two species were grown on 360 $\mu\textrm{g}$/$m\ell$ of titanium-ions, and they were found to be resistant to the titanium-ion. Both the wild-type and plasmid-cured E. coli showed good growth in a medium with 200 $\mu\textrm{g}$/$m\ell$ of titanium-ions. These results suggest that titanium-resistance was independent from the effects of the plasmid in E. coli.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.2
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• pp.91-94
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• 2001

Glass ceramics composed of (5-X)$Li_2O$ㆍ$XAg_2O$ㆍ36CaOㆍ$20TiO_2$.27$P_2O_5$(X=1 to 5) were prepared by melting process and 2 step heat treatment for nucleation at$610^{\circ}C$ and crystallization at $730^{\circ}C$, Fabricated crystal phases were $LiTi_2(PO_4)_3$(LTP),$AgTi_2(PO_4)_3$(AgTP)와 $\beta-Ca_3(PO_4)$. Antibacterial effects and characterizations of the glass ceramics as $Ag_2$O content were investigated. Staphylococcus aureus and Salmonella typhi were used in this study. Staphylococcus aureus and Salmonella typhi bacteria were removed 5 hours added after glass ceramics.

• Archives of Pharmacal Research
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• v.13 no.1
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• pp.74-77
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• 1990

N-(2-Amamantyl)-N-(5-arylhydrazono-6-methyl-4-oxopyrimidin-2-yl) guanidines (IIIa, b), 2-(2-admantyl-amino)-4-amino-s-triazine (IVa) and its 6-chloromethyl derivative (IVb) were prepared by cylization of 1-(2-admantyl) biguanide HCl (I) with ethyl 2-arylhydrazono-3-oxobutyrates (II), ethyl formate and ethyl chloroacetate, respectively. Where 1-(2-admantyl)-3-(4, 5-dioxo-2-imidazolidinylidene)guanidine (V) was used as intermediate for the synthesis of amides (VIIa, b), hydrazide (VIII) and azomethine derivatives (IX, b) of alkyl 2-(2-admantyl-amino)-4-amino-2-triazine-6-carboxylates (VI a, b). The antimicrobial testing of the prepared compounds proved that compound 1Xb was the most active. It showed a marked bacteriostatic effect against Staphylococcus aureus and Bacillus subtilis.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.47-53
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• 1998

5.7-Dichloro-8-hydroxyquinaldyl-N-ethylcarbamate, one of the carbamate derivative which are generally used as insecticide, was newly synthesized. Its physical properities were determined and chemical structure was indentified by means of I.R., nmr in addition to elemental analysis. The yield of addition, using triethylamine as catalyst, 5.7-dichloro-8-hydroxyquinaldine and isocyanate was better than that of condensation of 5.7-dichloro-8- hydroxyquinaldine with carbamoylchloride. The effect of the cornpond on rabbit's ileum, and antibacterial activity against Staphylococcus aureus, Salmonella typhi, Escherichia coli, and Pseudomonas aeruginosa were examined. It was observed that the dosage over 100 $\mu$g/ml of the compound relaxed rabbit's ileum and the same dosage of the compound inhibited growth of the above strains of bactera.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.183-188
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• 2002

Antibacterial glass ceramics composed of $5Li_2O{\cdot}36CaO{\cdot}20TiO_2{\cdot}27P_2O_5$ were Prepared. After ion exchange in the $AgNO_3$solution, crystallization phases were $AgTi_2(PO_4)_3$, $LiTi_2(PO_4)_3$ and $Ca_3(PO_4)_2$. In case of ion exchange, the crystallization phases started to be transformed from $LiTi_2(PO_4)_3$ to $AgTi_2(PO_4)_3$in 0.5 mole $AgNO_3$ solution and the transformation was almost completed in 1.0 mole. ion exchange rate of glass-ceramics powder, considering ion exchange time, was more fast than that of bulk. The bacteriostatic effect of the glass-ceramics on Staphyloroccus aureus and Salmonella typhi bacteria was more excellent than that of glass when the crystallization phase was transformed from LTP to AgTP.