• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.171-175
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• 1982

An oxytetracycline as being a tetracycline-antibiotic substance displayed a general synergism in the antimicrobial activity by the interaction of ginseng saponin and antibiotics, but did not to Sarcina maginata. Penicillin G.Na as being a $\beta$-lactam-antibiotic substance displayed a synergism in the antimicrobial activities by the addition of ginseng saponin to microorganisms used, but changed the effects in the antimicrobial activity of penicillin G.Na against the genus Serratia. An antimicrobial activity by the addition of ginseng saponin to antibiotics showed a non-specificity, and it varied synergism or antagonism to Gram-positive or Gram-negative bacterium. It was assumed that a drug-resistance could be eliminated by the dual administration of ginseng saponin and antibiotics.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.40-50
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• 2002

Fruit fly, Drosophila melanogaster has developed efficient immune mechanisms to prevent microbial infection, which are consisted of cellular and humoral responses. During the systemic or local infection, two distinct pathways (Toll and Imd) play major roles in antimicrobial peptide synthesis. The Toll pathway is required to defend Gram-positive bacterial and fungal infections, whereas the Imd pathway is important in Gram-negative bacterial infection. We have shown that the infection of the opportunistic Gram-negative bacterium, Pseudomonas aeruginosa strain PA14 (PA14) into fly dorsal thorax can kill the flies within 48 h ($100\%$ mortality) in our optimized infection condition, suggesting that the PA14 strain can cause disease progress in fly model system. We found that flies carrying a constitutively activated mutant form of the Toll receptor $(Tl^{10b})$ showed increased resistance to P. aeruginosa infection and that flies carrying mutations in the Toll signaling pathway as well as in the Imd signaling pathway was more susceptible to PA14 infection. All these results imply that the Toll pathway might be important in the resistance to this pathogenic Gram-negative bacterial infection.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.127-130
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• 1986

Naturally occurring diallyldihydroxybiphenyl compounds, magnolol and honokiol were reported to have potent antibacterial activities against most of Gram positive bacteria (1-4). To developmore potent antibacterial agents, some allyhydroxybiphenyl derivatives were synthesized from the starting compounds, p-phenyl-phenol (I) p-phenylphenol (IV), o, o-biphenol (VII) and p. p'-biphenol (XII). Among the newly synthesized compounds (III, VI, IX, XI, XIV and XVI), the antibacterial activities of 2-allyl-p-phenylphenol (VI), 6-ally-o, 0'-biphenol (IX), 2, 2'-diallyl-o, o'-biphenol (XIV) and 2, 2', 6-triallyl-p, p'-biphenol (XIV) were more potent than those of magnolol and bonokiol against a cariogenic bacterium, Stroptococcus matans ATCC OMZ 176.

• ALGAE
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• v.18 no.4
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• pp.355-360
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• 2003

A Gram (-), rod-shaped bacterium in size of 1.6-2.8 $\times$ 0.4 μm was isolated from a eutrophic reservoir, which exhibited growth-inhibiting effect against a bluegreen alga (Anabaena cylindrica). This isolate showed positive reactions for catalase and oxidase, and optimal conditions of 35-40°C and pH 9.0. This isolate was designated AC-1 in this manuscript. In a mixed-culture of A. cylindrica and AC-1, their growth patterns were inversely correlated and the bluegreen algal vegetative cells completely disappeared within 24-36 hours. AC-1 showed similar lytic activity in natural water as in an artificial medium. The lytic activity of AC-1 was dependent on the photosynthetic activity of A. cylindrica. When observed under phase contrast microscope, the isolate lysed vegetative cells of A. cylindrica in scattered state in a liquid medium, whereas heterocysts have not been lysed.

• Journal of Microbiology
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• v.40 no.1
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• pp.43-50
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• 2002

A cluster of genes encoding the pyruvate dehydrogenase complex (PDC) of Streptomyces seoulensis, a Gram-positive bacterium, was cloned and sequenced. The genes of S. seoulensis consist of four open reading frames. The first gene, lpd, which encodes a lipoamide dehydrogenase, is followed by pdhB encoding a dihydrolipoamide acetyltransferase (E2p), pdhR, a regulatory gene, and pdhA encoding a pyruvate dehydrogenase component (Elp). Elp had an unusual homodimeric subunit, which has been known only in Gram-negative bacteria S. seoulensis E2p contains two lipoyl domains like those of humans and Streptomyces faecalis. The pdhR gene appears to be clustered with the structural genes of S. seoulensis PDC. The PdhR-overexpressed S. seoulensis howed growth retardation and the decrease of Elp, indicating that PdhR regulates the function of PDC by repressing the expression of Elp. A strain of Streptomyces licidans overexpressing S. seoulensis PdhR showed a significant decreasein the level of actinorhodin, implying a regulatory role for Streptomyces PDC in antibiotic biosynthesis.

• Animal cells and systems
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• v.12 no.1
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• pp.41-46
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• 2008

A bacterium strain called Bacillus coagulans was isolated from an industrial wastewater drainage and selected for its antimicrobial activities against bacteria and fungi. Characterization studies strongly suggested that this strain is Bacillus coagulans. Antimicrobial activity was found against gram-positive, gram-negative bacteria and yeast strain. Maximal activity was observed after 24 h when incubated at $30^{\circ}C$ and pH 8. The activity was found to be stable at $75^{\circ}C$ for 30 min and at pH range of 2-12. Analysis of the antimicrobial compound by SDS-PAGE suggested a molecular mass of approximately 7.5 KDa. The substance was characterized as a bacteriocin, because of its proteinaceous nature and low molecular weight. Our bacteriocin could potentially be used as a food preservative, because of its thermostable property and broad antimicrobial spectrum.

• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.129-133
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• 1986

Antimicrobial activities of aucubin, an iridoid glycoside, were investigated. Gram-positive bacterium, S. aureus appeared to be more sensitive to aucubin's aglucone, aucubigenin than Gram-negative, E. coli did. Antimicrobial activities produced by aucubigenin may result in part from the inhibition of RNA and protein biosyntheses in bacterial cells. The conversion of aucubin iridoid glycoside into aucubigenin, an aglucone, appears to be a prerequisite step to exhibit the antimicrobial activities.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.792-796
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• 2005

Disk assays on the compounds (10 and 12) showed both to have antifungal activity against the dermatophytic fungus Trichophyton mentagrophytes ATCC 28185, (1 and 3 mm inhibition zones at $60\;{\mu}g/disc$), but not against the Gram-positive bacterium B. subtilis or the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa or fungi Cladosporium resinae and Candida albicans. However, the compound (13) did not show against antifungal activity. The geranyloxy compounds (10, 12, and 13) were cytotoxic to P388 murine leukaemia cells ATCC CCL 46 P388D1, ($IC_50$ >6,250 ng/mL at $7.5\;{\mu}g/disc$). These results suggest that The geranyloxy compounds possesses antimicrobial and antitumor activities.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.81-85
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• 2003

Direct analysis of microbes such as either gram-positive or gram-negative bacteria without cell lysis was investigated using capillary electrophoresis. Bacteria cells were directly introduced into the microbore fusedsilica capillary, then separated under high electric field in less than 15 min. It was found that a proper dispersion of bacteria cells was important for reproducible results. Migration behavior of bacteria at different storage condition was investigated and many unexpected peaks were observed from bacteria stored at room temperature due to the distortion of cells. This phenomenon was attributed to the change of size and shape of the same bacterium and confirmed by the scanning electron microscopic images.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.905-913
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• 2014

Lj-RGD3, an RGD (Arg-Gly-Asp) toxin protein from the salivary gland of Lampetra japonica, exhibits antifungal activity against Candida albicans. Lj-RGD3 has three RGD motifs and shows homology to histidine-rich glycoprotein. We synthesised two mutant derivatives of Lj-RGD3: Lj-26, which lacks all three RGD motifs and contains no His residues; and Lj-112, which lacks only the three RGD motifs. We investigated the effects of the wild-type and mutated toxins on a gram-positive bacterium (Escherichia coli), a gram-negative bacterium (Staphylococcus aureus), and a fungus (C. albicans). rLj-RGD3 and its mutants exhibited antifungal but not antibacterial activity, as measured by a radial diffusion assay. The C. albicans inhibition zone induced by rLj-112 was larger than that induced by the other proteins, and its inhibitory effect on C. albicans was dose-dependent. In viable-count assays, the rLj-112 MIC was $7.7{\mu}M$, whereas the MIC of the positive control (ketoconazole) was $15{\mu}M$. Time-kill kinetics demonstrated that rLj-112 effectively killed C. albicans at $1{\times}$ and $2{\times}$ MIC within 12 and 6 h, respectively. Electron microscopy analysis showed that rLj-RGD3 and rLj-112 induced C. albicans lysis. Our results demonstrate a novel anticandidal activity for rLj-RGD3 and its mutant derivatives.