• Archives of Pharmacal Research
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• v.13 no.4
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• pp.385-387
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• 1990

3-[(1-Methyl-1H-tetrazol-5-y)thiomethyl] is one of the most important side chains in cephaloporins. This side chain which occures in numerous antibacterial agents, suc as cefamandole, latamoxef, cefoperazone, and cefmenoxime, contributes remarkable potency and broad spectrum. For the continuous work of study on the development of broad spectrum cephalosporins, we become interested in the effect of structural modification of the substituent at the N-1 position of mercaptoterazole toward biological activity because our recent work had demonstraated that the arylsubstituted mercaptotetrazoles (Fig. 1) had favorable effect on the activity against gram-positive bacteria. The main focus of this report was to investigate the relationship between activity and functional groups in the mercaptotetrazole.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.951-962
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• 2004

Hot water extracts of 141 indigenous plants were screened for antibacterial activity against 7 Gram (+) and 12 Gram (-) bacteria by agar diffusion method. Of the 141 plants tested, 55 showed antibacterial activity against one or more species of Gram (+) bacteria and especially extracts of Oenothera stricta Ledebour (Onagraceae), Quercus variabilis Blume (Fagaceae), Alnus firma (Betulaceae), Geranium thunbergii (Geraniaceae), Lagerstroemia indica (Lythraceae) showed broad spectrum antibacterial activity on over 6 strains. Of the 141 plants tested, 45 showed antibacterial activity against one or more species of Gram (-) bacteria and especially extracts of Oenothera stricta Ledebour (Onagraceae), Punica granatum (Lythraceae), Quercus variabilis Blume (Fagaceae), Schizandra chinensis Baillon (Magnoliaceae), Alnus firma (Betulaceae), Alnus hirsuta (Betulaceae), Magnolia kobus (Magnoliaceae) showed broad spectrum antibacterial activity on over 8 strains. The most active antibacterial plants were Oenothera stricta Ledebour (Onagraceae), Punica granatum (Lythraceae), Quercus variabilis Blume (Fagaceae), Schizandra chinensis Baillon (Magnoliaceae) which are edible as permitted by Korea Food & Drug Adminstration. With in-depth research, the hot water extracts of these plants can be applied as food preservatives and alternatives of antimicrobials for livestock feeds.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.42-50
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• 2009

Fifty-four Pectobacterium carotovorum subsp. carotovorum strains isolated in Korea were characterized by a spectrum of antibacterial activities against 7 indicator strains chosen to represent various regions and host plants. All P. carotovorum subsp. carotovorum isolates tested could be grouped into 4 classes depending on the pattern of antibacterial substance production. All tested strains had DNA fragment(s) homologous to the genes encoding carotovoricin and 21 of them had genes homologous to DNA invertase. Sixteen strains had genes homologous to the genes encoding carocin S1. Several isolates produced antibacterial substances active against strains in Brenneria, Pantoea, and Pectobacterium genera that belonged formerly to the genus Erwinia. Strains in Pseudomonas or Xanthomonas sp. were not sensitive to the antibacterial substances produced by P. carotovorum subsp. carotovorum, except for X. albilineans that was sensitive to antibacterial substances produced by most strains in P. carotovorum subsp. carotovorum and P. betavasculorum KACC10056. These results demonstrated the diverse patterns of antibacterial substance production and the possibility of the existence of new antibacterial substance(s) produced by P. carotovorum subsp. carotovorum isolated in Korea.

• BMB Reports
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• v.29 no.6
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• pp.545-548
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• 1996

CA(1-8)ME(1-12), the CA-ME hybrid peptide of the amino terminal segments of cecropin A (CA) and melittin (ME), has been reported to have a broad spectrum and improved potency without a hemolytic property. In order to obtain new synthetic peptides with powerful antibacterial activity without hemolytic activity, several hybrid peptides were designed from the sequences of CA, ME, magainin 2, bombinin and lactoferricin. All hybrid peptides were constructed to form an amphipathically basic-flexible-hydrophobic structure and synthesized by the solid phase method. Their hemolytic activities against human red blood cells and antibacterial activities against both Gram-positive and Gram-negative bacteria were detennined. CA(1-8)MA(1-12), CA(1-8)BO(1-12), MA(10-17)ME(1-12) and LF(20-29)ME(1-12) showed comparable activities with broad spectra against both Gram-positive and Gram-negative bacteria relative to CA(1-8)ME(1-12) but without hemolytic properties. These hybrid peptides, therefore, could be useful as model peptides to design a novel peptide with improved antibacterial activity and study on structure-activity relationships of antimicrobial peptides.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.872-881
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• 2012

The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 $log_{10}$, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GC-MS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.61-74
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• 2023

The global increase in multidrug-resistant (MDR) bacteria has inspired researchers to develop new strategies to overcome this problem. In this study, 23 morphologically different, soil-isolated actinomycete cultures were screened for their antibacterial ability against MDR isolates of ESKAPE pathogens. Among them, isolate BOGE18 exhibited a broad antibacterial spectrum, so it was selected and identified based on cultural, morphological, physiological, and biochemical characteristics. Chemotaxonomic analysis was also performed together with nucleotide sequencing of the 16S rRNA gene, which showed this strain to have identity with Streptomyces lienomycini. The ethyl acetate extract of the cell-free filtrate (CFF) of strain BOGE18 was evaluated for its antibacterial spectrum, and the minimum inhibitory concentration (MIC) ranged from 62.5 to 250 ㎍/ml. The recorded results from the in vitro anti-biofilm microtiter assay and confocal laser scanning microscopy (CLSM) of sub-MIC concentrations revealed a significant reduction in biofilm formation in a concentration-dependent manner. The extract also displayed significant scavenging activity, reaching 91.61 ± 4.1% and 85.06 ± 3.14% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. A promising cytotoxic ability against breast (MCF-7) and hepatocellular (HePG2) cancer cell lines was obtained from the extract with IC₅₀ values of 47.15 ± 13.10 and 122.69 ± 9.12 ㎍/ml, respectively. Moreover, based on gas chromatography-mass spectrometry (GC-MS) analysis, nine known compounds were detected in the BOGE18 extract, suggesting their contribution to the multitude of biological activities recorded in this study. Overall, Streptomyces lienomycini BOGE18-derived extract is a good candidate for use in a natural combating strategy to prevent bacterial infection, especially by MDR pathogens.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.109-114
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• 2014

Objectives: Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans and Lactobacillus. Materials and Methods: Ninety discoid tablets containing 0%, 1% nano-silver and 1% nano zinc-oxide particles were prepared from flowable composite resin (n = 30). The antibacterial properties of composite resin discs were evaluated by direct contact test. Diluted solutions of Streptococcus mutans (PTCC 1683) and Lactobacillus (PTCC 1643) were prepared. 0.01 mL of each bacterial species was separately placed on the discs. The discs were transferred to liquid culture media and were incubated at $37^{\circ}C$ for 8 hr. 0.01 mL of each solution was cultured on blood agar and the colonies were counted. Data was analyzed with Kruskall-Wallis and Mann-Whitney U tests. Results: Composites containing nano zinc-oxide particles or silver nanoparticles exhibited higher antibacterial activity against Streptococcus mutans and Lactobacillus compared to the control group (p < 0.05). The effect of zinc-oxide on Streptococcus mutans was significantly higher than that of silver (p < 0.05). There were no significant differences in the antibacterial activity against Lactobacillus between composites containing silver nanoparticles and those containing zinc-oxide nanoparticles. Conclusions: Composite resins containing silver or zinc-oxide nanoparticles exhibited antibacterial activity against Streptococcus mutans and Lactobacillus.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.93-99
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• 2018

Lysozyme is present in tears and has the ability to inhibit bacterial growth. In addition, it acts as a physiological scavenger for harmful substances. In the present study, sixteen tear samples from people of different ages were evaluated for their antibacterial spectrum against selected bacterial strains (Escherichia coli, Shigella sonnei, Staphylococcus aureus, Salmonella enterica Typhi). A radial diffusion assay was used to evaluate the antibacterial potential of tear samples. To correlate the antibacterial activities of these tear samples, the concentration of lysozyme in the tear samples was also determined. Ampicillin was used as a standard drug. The zone of inhibition (mm) was used to measure the antibacterial property of the tears. All samples showed good antibacterial activities. The tear samples of children showed antibacterial activities in the range of 4.40~5.00 mm inhibition zones against the selected bacterial strains. The tear samples from the young and adults showed good antibacterial potential with a zone of inhibition in the range of 3.20~4.00 and 4.00~5.50 mm, respectively. The tear samples from the old age group showed inhibition zones from 1.50~5 mm. The adult tear samples showed the maximum inhibition against the selected bacterial strains among all groups. The lysozyme concentration was 1.7 mg/mL, 1.95 mg/mL, 2.13 mg/mL, and 1.76 mg/mL for children, young, adults, and elderly, respectively. In conclusion, the tears from adults have the high inhibition potential. In addition, this data also showed that the lysozyme contents in the tear sample increased with age until 40~42 years.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.12-12
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• 1997

CFC-222 is a novel fluoroqinolone antibacterial agent synthesized and under development by the Cheil Jedang Corporation, Korea. CFC-222 exerts the antibacterial activity by inhibition of bacterial DNA gyrase leading to bactericidal action. In in vitro and in vivo preclinical testing, CFC-222 has been shown to possess a broad spectrum of antibacterial activity. In particular CFC-222 is very potent against Gram-positive bacteria such as Staphylococcus spp., Streptocuccus spp. (in particular penicillin G-resistant and -susceptible S. pneumoniae) and Enterococcus spp. when compared to other quinolones (ciprofloxacin, ofloxacin or lomefloxacin). CFC-222 also showed potent activity against the methicillin resistant clinical isolates of S. aureus (MRSA). Against Gram-negative bacteria (E. coli, Pseudomonas and Sarcina) the activity of CFC-222 was slightly weaker than that of ciprofloxacin, but was more potent than that of ofloxacin or lomefloxacin. In urinary systemic infections caused by both Gram-positive and -negative bacteria, CFC-222 demonstrated a potent therapeutic efficacy in particular against Cram-positive bacteria S. aureus, S. pyrogen 203 and S. pneumonia TypeIII.

• Korean Journal of Veterinary Research
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• v.49 no.2
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• pp.135-139
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• 2009

Streptomyces (S.) fradiae is a microbe with broad-spectrum antimicrobial activity, isolated from soil. In the present study, antibacterial effects of S. fradiaea against Salmonella (S.) gallinarum was determined. S. fradiae inhibited growing of S. gallinarum in Luria-Bertani media agar. Moreover, ingestion of S. fradiae markedly inhibited mortality of chickens experimentally infected with S. gallinarum. There is no side effect by S. fradiaeon, in safety of chickens and antibiotic material residues in chicken meat. Taken together, S. fradiae have the antibacterial effects against S. gallinarum. Therefore, we concluded that S. fradiae might be a good microbial candidate for treatment or control of fowl typhoid in chickens.