• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.485-491
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• 2015

This study was performed to investigate thermophilic bacteria from soil having broad antifungal spectrum against Rhizoctonia solani, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f.sp. lycopersici, and Botrytis cinerea. One isolate selected could resist heat shock of $60^{\circ}C$ for one hour, and had broad antifungal activity in dual culture assay against all tested fungal pathogens and was identified as Bacillus amyloliquefaciens Y1 using 16S rRNA gene sequence. Further investigation for antifungal activity of bacterial culture filtrate (BCF) and butanol crude extract (BCE) of various concentrations showed broad spectrum antifungal activity and fungal growth inhibition significantly increased with increasing concentration with highest growth inhibition of 100% against R. solani with 50% BCF and 11 mm of zone of inhibition against R. solani with 4 mg BCE concentration. Treatment of butanol crude extract resulted in deformation, lysis or degradation of C. gloeosporioides and P. capsici hyphae. Furthermore, B. amyloliquefaciens Y1 produced volatile compounds inhibiting growth of R. solani (70%), C. gloeosporioides (65%) and P. capsici (65-70%) when tested in volatile assay. The results from the study suggest that B. amyloliquefaciens Y1 could be a biocontrol candidate to control fungal diseases in crops.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.646-651
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• 2005

The growth responses of Ruta chalepensis leaf-derived materials toward human intestinal bacteria were examined. The biologically active constituent of the R. chalepensis extract was characterized as quinoline-4-carboxaldehyde($C_{10}H_{7}NO$). The growth responses varied depending on the bacterial strain, chemicals, and dose tested. At 0.25 and 0.1 mg/disk, quinoline-4-carboxaldehyde strongly inhibited the growth of Clostridium perfringens and weakly inhibited the growth of Escherichia coli without any adverse effects on the growth of three lactic acid bacteria. Furthermore, at 0.05 and 0.025 mg/disk, this isolate showed moderate activity against C. perfringens. In comparison, chloramphenicol at as low as 0.01 mg/disk significantly inhibited the growth of all bacteria tested, and cinnamaldehyde at 0.25 mg/disk did not inhibit Bifidobacterium bifidum, B. longum, E. coli, and Lactobacillus acidophilus, with the exception of C. perfringens. The structure-activity relationship revealed that quinoline-3-carboxaldehyde had strong growth inhibition against C. perfringens, but quinoline, quinoline-3-carboxylic acid, and quinoline-4-carboxylic acid did not inhibit the growth of B. bifidum, B. longum, C. perfringens, E. coli, and L. acidophilus. These results indicate that the carboxyl aldehyde functional group of quinolines seems to be required for growth-inhibiting activity against C. perfringens, thus indicating at least one of the pharmacological actions of R. chalepensis leaf.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.184-188
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• 2013

In the continued search for inhibitors of enoyl-acyl carrier protein (ACP) reductase, we found that four acylbenzenediol sulfate metabolites from Streptomyces sp. AN1761 potently inhibited bacterial enoyl-ACP reductases of Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium tuberculosis. Their structures were identified as panosialins A, B, wA, and wB by MS and NMR data. They showed stronger inhibition against S. aureus FabI and S. pneumoniae FabK with $IC_{50}$ of 3-5 ${\mu}M$ than M. tuberculosis InhA with $IC_{50}$ of 9-12 ${\mu}M$. They also exhibited a stronger antibacterial spectrum on S. aureus and S. pneumoniae than M. tuberculosis. In addition, the higher inhibitory activity of panosialin wB than panosialin B on fatty acid biosynthesis was consistent with that on bacterial growth, suggesting that they could exert their antibacterial activity by inhibiting fatty acid synthesis.

• YAKHAK HOEJI
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• v.34 no.6
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• pp.434-438
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• 1990

The methanolic extract of the root-bark of Morus alba L.(Mulberry tree) has the potent antibacterial activity against Streptococcus mutans. Its active component was identified to be sanggenon C. The active component had stronger anti-bacterial activity than berberine, having minimum inhibitory concentration(MIC) of $25\;{\mu}g/ml$. Moreover, the inhibitory effect of this component on the cellular adherence of Streptococcus mutans to glass surfaces also was more remarkable than that of berberine in the presence of glucosyltransferase(GTase) and sucrose in vitro. These results indicate that sanggenon C may play an important role in inhibiting plaque formation and caries incidence.

• Korean Journal of Pharmacognosy
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• v.34 no.2 s.133
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• pp.142-144
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• 2003

Acetone extracts of 301 strains of marine-derived fungus were tested for antimicrobial activity against three strains of bacteria. The bacteria consisted of three pathogens, Staphylococcus aureus, methicillin-resistant S. Aureus, and multidrug-resistant S. aureus. The acetone extracts of 10 strains (MFA117, MFA130, MFA134, MFA206, MFA217, MFA268, MFA277, MFA291, MFA292, MFA301) showed strong activity, inhibiting 100% of the bacterial growth. These antimicrobial active strains were cultlued in SWS medium on a 1 L scale and the resulting broth and mycelium were extracted to afford mycelium extract (000M) and broth extract (000B), respectively. Antimicrobial activity for all extracts has been tested as the results, the mycelium extract of one strain (217M) and the broth extracts of 9 strains (117B,130B, 134B, 206B, 268B, 277B, 291B, 292B, 301B) exhibited relatively high levels of activity at minimal inhibitory concentration (MIC) values of $500-125\;{\mu}g/mL$ range. Among them, the extracts, 277B, 291B, 292B and 301B showed the most significant antimicrobial activity with $IC_{50}$ values of $125\;{\mu}g/mL$.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.177-180
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• 2015

For prevention of atrophic rhinitis of swine by Bordetella bronchiseptica and fowl typhoid by Salmonella gallinarum, bacterial strains showing antimicrobial activity against those pathogenic bacteria were isolated from various samples collected at animal farms. Among 372 bacterial isolates strain TK3 showed the highest antibacterial activity against both pathogens, and was identified as Bacillus amyloliquefaciens by 16S rRNA gene sequence analysis. B. amyloliquefaciens TK3 could inhibit growth of both pathogens by secretion of antibacterial compounds such as siderophore, rhamnolipid and antimicrobial peptide. Production radius of siderophore on Chrome azurol S agar plate by strain TK3 was 0.53 cm after 14 days of incubation, and concentration of siderophore in King's B medium was 1.06 mmol/ml. It also secreted 82.4 mg/L of rhamnolipid, and antimicrobial peptide that completely inhibited growth of both pathogens at concentration of $30{\mu}l/ml$ in LB medium.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.29-33
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• 2004

Cranberries have long been used by lay people to relieve the symptoms of urinary tract infections. Recent research has determined that the component of cranberry called proanthocyanidin (PAC) is the primary mechanism for inhibiting P-fimbriated E.coli adhesion to uroepithelial cells in vitro. A series of experiments were performed to determine the effects of PAC on growth and adhesion of uropathogenic E. coli and Staphylococcus aureus to urinary catheter material. The results showed that PAC-inhibited binding of Gram positive S. aureus to collagen coated surfaces and significantly decreased the growth of these bacteria. P-fimbriated E.coli did not bind well to the biomaterial and their growth was unaffected by the cranberry extract with the exception of some loss in viability at 1000 $\mu\textrm{g}$/mL after 5 to 18 hours of exposure. This is the first report of the potential for cranberries to interfere with the adhesion and growth of S. aureus, a multi-drug resistant organisms responsible for morbidity and mortality especially in hospitalized patients.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.529-536
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• 2003

The growth-inhibitory activity of Cassia tora seed-derived materials against seven intestinal bacteria was examined in vitro, and compared with that of anthraquinone, anthraflavine, anthrarufin, and 1-hydroxyanthraquinone. The active constituent of C. tore seeds was characterized as quinizarin, using various spectroscopic analyses. The growth responses varied depending on the compound, dose, and bacterial strain tested. At 1 mg/disk, quinizarin exhibited a strong inhibition of Clostridium perfringens and moderate inhibition of Staphylococcus aureus without any adverse effects on the growth of Bifidobacterium adolescentis, B. bifidum, B. longum, and Lactobacillus casei. Furthermore, the isolate at 0.1 mg/disk showed moderate and no activity against C. perfringens and S. aureus. The structure-activity relationship revealed that anthrarufin, anthraflavine, and quinizarin moderately inhibited the growth of S. aureus. However. anthraquinone and 1-hydroxyanthraquinone did not inhibit the human intestinal bacteria tested. As for the morphological effect of 1 mg/disk quinizarin, most strains of C. perfringens were damaged and disappeared, indicating that the strong activity of quinizarin was morphologically exhibited against C. perfringens. The inhibitory effect on aflatoxin $B_1$ biotransformation by anthraquinones revealed that anthrarufin ($IC_50,\;11.49\mu\textrm{M}$) anthraflavine ($IC_50,\;26.94\mu\textrm{M}$), and quinizarin ($IC_50,\;4.12\mu\textrm{M}$), were potent inhibitors of aflatoxin ${B_1}-8,9-epoxide$ formation. However, anthraquinone and 1-hydroxyanthraquinone did not inhibit the mouse liver microsomal sample to convert aflatoxin $B_1$ to aflatoxin ${B_1}-8,9-epoxide$. These results indicate that the two hydroxyl groups on A ring of anthraquinones may be essential for inhibiting the formation of aflatoxin ${B_1}-8,9-epoxide$. Accordingly, as naturally occurring inhibitory agents, the C. tora seed-derived materials described could be useful as a preventive agent against diseases caused by harmful intestinal bacteria, such as clostridia, and as an inhibitory agent for the mouse liver microsomal conversion of aflatoxin $B_1$ to aflatoxin ${B_1}-8,9-epoxide$.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.87-89
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• 2017

Apo-transferrin is an iron-binding protein that has been reported to have an antimicrobial effect. It is considered a major component of the host defense mechanism as it limits microbial access to iron. This study was performed to investigate whether bovine apo-transferrin would have an inhibitory effect on the growth of S. pseudintermedius, which is one of the most isolated bacteria from dogs, and to compare the antimicrobial efficacy with bovine holo-transferrin. S. pseudintermedius were grown at $37^{\circ}C$ in 96-well culture plates using Muller Hinton broth containing bovine apo-transferrin or bovine holo-transferrin at concentrations ranging from 0.5 or 2.5 to 5.0 mg/ml. The optical densities of the wells were then measured at 570 nm. In this study, the apo-transferrin showed dose-dependent antimicrobial effect against S. pseudintermedius while holo-transferrin did not inhibit the growth of S. pseudintermedius effectively. The results suggest that iron deprivation is an important pathway for inhibiting bacterial growth and bovine apo-transferrin has great antimicrobial effects against S. pseudintermedius.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.444-450
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• 2003

In order to develop an effective means to treat P. aeruginosa infections, we have purified P. aeruginosa outer membrane proteins (OMPs)-specific human IgG antibody. In this study, we investigated the protective activity of the purified anti-OMPs IgC against P. aeruginosa infection in a rabbit endophthalmitis model. Rabbits were inoculated by an intravitreal injection with P. aeruginosa, and treated with a single dose of 1 mg anti-P. aeruginosa OMPs IgG. All the control rabbits predominantly developed edematous responses and opacity in the eyes, but the rabbits treated with the antibody showed only very limited degree of edema. Aliquots of the vitreous humor were extracted and analyzed for the number of viable bacteria and endotoxin level. The results showed that the anti-OMPs IgC significantly reduced the bacterial count compared with the control group, and that the endotoxin level of the vitreous from the IgG-treated rabbits was more than 70-fold lower 6 h after the administration than the control animals. These data suggested that the anti-P. aeruginosa OMPs IgG is effective in inhibiting the bacterial growth and thereby in reducing endotoxin levels in the vitreous, warranting further development of the anti-P. aeruginosa OMPs IgG as a therapeutic means for treating Pseudomonas endophthalmitis.