• BMB Reports
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• v.32 no.1
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• pp.12-19
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• 1999

Gaegurin 4 (GGN4), a broad-spectrum antibiotic, is a 37-amino acid peptide isolated from the Korean frog, Rana rugosa. In this study, we have chemically synthesized and purified GGN4 analogues where the C-terminal portion is truncated and/or substituted with tryptophan. These peptides show significantly different biological activities depending on the location of tryptophan and the number of amino acids truncated from the C-terminal end. While deletion of 9 amino acids from the C-terminal seems to be marginally tolerable in maintaining the antimicrobial activity, further deletion of up to 14 amino acid residues decreases the potency by more than 60-fold towards Gram-positive, and 10-fold towards Gram-negative, bacteria. Surprisingly, the reduced activity of the shorter peptide can be completely restored by a single substitution of aspartic acid 16 to tryptophan 16 (D16W). Also, the truncation seems to decrease the specificity of antibiotic activity more towards Gram-positive than towards Gram-negative bacteria studied. These data suggest a partial role of the C-terminal region in determining the binding specificity and the activity of peptides upon binding to their target cell membranes.

• Advances in Traditional Medicine
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• v.7 no.3
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• pp.286-289
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• 2007

Heracleum nepalense D Don. (Umbelliferae) is a small shrub having high glabrescent stem found in stream banks in Sikkim. Various medicinal properties which include antidiarrhoeal, antiseptic, anti-influenzal etc. have been attributed for this plant in the traditional system of medicine in Sikkim. In present investigation the methanol extract of roots of Heracleum nepalense was subjected for its effectiveness against both Gram-positive and Gram-negative bacteria causing diarrhoea. The roots extract was tested for its minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative organisms causing diarrhoea. Further, the zones of inhibition produced by the crude extract against few sensitive strains was measured and compared with those of standard antibiotic ciprofloxacin. It is evident that the methanol extract is very active against the bacteria causing diarrhoea at low concentrations. The antibacterial efficacy of the root extract was found to decrease in the following order against different tested bacterial strains like Shigella dysenteriae, Escherichia coli, Shigella boydii, Vibrio cholerae, Salmonella typhimurium.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.176-182
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• 2008

In the present study, a control methodology utilizing airborne silver nanoparticles is suggested and tested with respect to its potential to control Gram-positive Staphylococcus epidermidis and Bacillus subtilis, and Gram-negative Escherichia coli bacteria bioaerosols deposited on filters. As it is known that the Gram-negative bacteria are sensitive to airflow exposure, the main focus of this study for testing the airborne silver nanoparticles effect was the Gram-positive Staphylococcus epidermidis and Bacillus subtilis bacteria bioaerosols whereas Escherichia coli bioaerosols were utilized for comparison. Airborne bacteria and airborne silver nanoparticles were quantitatively generated in an experimental system. Bioaerosols deposited on the filter were exposed to airborne silver nanoparticles. The physical and biological properties of the airborne bacteria and airborne silver nanoparticles were measured via aerosol measurement devices. From the experimental results, it was demonstrated that this method utilizing airborne silver nanoparticles offers potential as a bioaerosol control methodology.

• Polymer(Korea)
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• v.30 no.5
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• pp.397-401
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• 2006

In this study, we coated the polypropylene filter with titania sol and investigated various characteristic such as its deodorization efficiency and sterilization effect of gram negative bacillus Escherichia coli(ATCC 25922) and gram positive bacillus Staphylococcus aureus(ATCC 6538). As the results, in case of titania sol coated polypropylene filter, the deodorization rate of ammonia, trimethylamin and acetic acid which cause indoor air pollution was 66%, 90% and 16% respectively. Also. the sterilization rate of gram negative bacillus Escherichia coli(ATCC 25922) and gram positive bacillus Staphylococcus aureus(ATCC 6538) was 99.9% after 24 hours.

• 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.

• Natural Product Sciences
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• v.13 no.4
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• pp.279-282
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• 2007

The aim of the present study was to investigate the various chemical components present in the cone volatile oil of Cupressus macrocarpa and also determine its antimicrobial activity. Totally 13 compounds were identified with 99.99% by GC-MS analysis. The major compounds identified were terpinene-4-ol (19.42%), dinopol (15.63%), ${\alpha}$-pinene (13.58%), and ${\beta}$-pinene (12.16%). The antimicrobial activity was carried out for the oil and a 2% cream formulation using cup plate method by measuring the zone of inhibition. The gram positive organisms used were Bacillus subtilis, Staphylococcus aureus, Bacillus megaterium, and Bacillus cogulans. The gram negative organisms used were Escherichia coli, Kleibseilla pneumonia, Pseudomonas aeruginosa and Salmonella typhi. In vitro antifungal studies were also carried out by using organisms, Candida albicans, Aspergillus flavus, Trichoderma lignorum and Cryptococcus neoformans. The standard drugs used were penicillin ($100{\mu}g/mL$), gentamycin ($100{\mu}g/mL$) and griseofulvin ($100{\mu}g/mL$) for gram positive bacteria, gram negative bacteria and fungi respectively. Both oil and cream formulation showed good activity against fungi than bacteria. This study is being reported for the first time on cone volatile oil of this plant.

• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.31-36
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• 1998

A broad spectrum of antibiotic action was studied with Centipedin purified from centipede Scolopendra subspinipes multilans L. Koch aganist gram-positive, gram-negative bacteria and fungi. The minimal inhibitory concentrations(MICs) were determined in liquid medium. The significant antibiotic activity was obtained aganist gram-negative Klebsiella pneumoniae ATCC 8308 responsible for causing infection at lung and intestine. The MIC value against Klebsiella pneumoniae ATCC 8308 was $2{\mu}g/ml$, and this Centipedin was active against Proteus vulgaris NRRL B-123. In addition, it has been shown that Centipedin blocks procaryotic RNA transcription and a little of DNA replication system in vitro. Centipedin did not exhibit any significant cytotoxicity against animal cells such as human blood leukemia (HL-60) and mouse B lymphocyte myeloma cell.

• Journal of Korean Foot and Ankle Society
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• v.25 no.2
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• pp.100-107
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• 2021

Purpose: The present study aimed to develop guidelines regarding initial choice of antibiotics for diabetic foot ulcers (DFU) by investigating bacterial isolates. Materials and Methods: This study included 223 DFU patients that visited a single tertiary hospital and underwent bacterial culture between January 2016 and February 2020. The study was conducted in two parts: 1) to compare bacterial isolates and wound healing according to comorbidities such as chronic kidney disease (CKD) and peripheral artery disease (PAD), and 2) to compare bacterial isolates according to wound depth using the Wagner classification. Results: Of the 223 patients, 43 had CKD (group A), 56 had PAD (group B), 30 had CKD and PAD (group C), and 94 had none of these comorbidities (group D). The isolation rate for multidrug-resistant gram-negative bacteria (MRGNB) and gram-negative to gram-positive bacteria ratio were highest in group C (p=0.018, p=0.038), and the proportion that achieved wound healing was lowest in group C (p<0.001). In the second part of the study, subjects were classified into 5 grades by wound depth using the Wagner classification; 13 grade I, 62 grade II, 60 grade III, 70 grade IV, and 17 grade V. No significant difference was observed between these grades in terms of isolation rates or gram-negative to gram-positive bacteria ratios. Conclusion: This study suggests antibiotics that cover gram-negative bacteria including MRGNB produces better results in the presence of CKD and PAD and that initial antibiotic choice should be based on the presence of CKD and PAD rather than wound depth.

• Journal of Microbiology
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• v.41 no.3
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• pp.183-188
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• 2003

We isolated and cultured bacteria that inhabited marine biofilms, and identified them by phylogenetic analysis using 16S rDNA sequences. In the marine environment, biofilms cover most subtidal and intertidal solid surfaces such as rocks, ships, loops, marine animals, and algae. The bacteria in most biofilms are embedded in extracellular polymeric substances that comprise mainly of exopolysaccharides. The exopolysaccharides are excreted from multiple bacterial species; therefore, biofilms are a good source for screening exopolysaccharide-producing bacteria. Thirty-one strains were cultured, and a total of 17 unique strains were identified. Phylogenetic analysis using 16S rDNA sequences indicated that the 17 strains belonged to ${\alpha}$-Proteobacteria (Ochrobactrum anthropi, Paracoccus carotinifaciens); ${\gamma}$-Proteobacteria (Pseudoalteromonas agarovorans, P. piscicida, Pseudomonas aeruginosa, Shewanella baltica, Vibrio parahaemolyticus, V. pomeroyi); CFB group bacteria (Cytophaga latercula, Tenacibaculum mesophilum); high GC, Gram-positive bacteria (Arthrobacter nicotianae, Brevibacterium casei, B. epidermidis, Tsukamurella inchonensis); and low GC, Gram-positive bacteria (Bacillus macroides, Staphylococcus haemolyticus, S. warneri).

• YAKHAK HOEJI
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• v.56 no.5
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• pp.304-308
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• 2012

In vitro antibacterial activity of DW286 was tested against recently collected clinical isolates of Gram-positive strains by the two fold agar dilution method. In vivo activity of DW286 was also determined against systemic infections in mice caused by Staphylococcus aureus. DW286 showed 16~64-fold more potent in vitro activities than ciprofloxacin against Gram-positive bacteria. Against systemic infection model caused by two S. aureus strains, one being methicillin-susceptible and the other methicillin-resistant, DW286 ($ED_{50}s$, 0.16 mg/kg and 4.36 mg/kg, respectively) was more potent than gemifloxacin (1.37 mg/kg, 26.58 mg/kg, respectively).