• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.26-33
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• 2002

The seven strains, Pseudomonas paucimobilis, Pseudomonas cepacia, Staphylococcus auricularis, Staphylococcus saprophyticus, Acidovorax spp., Acinetobacter calcoaceticus, and Actinobacillus capsulatus were tested with three slimicides. Most of the tested bacteria were inhibited with slimicide K (an isothiazolin based compound), even at its low concentration, except for Actinobacillus capsulatus and Staphylococcus auricularis. Both slimicides B (an organic bromine based compound) and S (aldehydes) also couldn't prevent these two strains even at their highest concentration. Five different sizes of plasmid DNA were isolated from Actinobacillus capsulatus. Staphylococcus auricularis, a gram-positive bacteria, showed the slimy substances around its cell distinctively. The results suggest that two strains, Actinobacillus capsulatus, Staphylococcus auricularis, have presumably developed a resistance to the slimicide, by plasmid DNA or slimy substance. Our findings also suggest that not only gram-negative bacteria, but also gram-positive bacteria should not be neglected

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.597-600
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• 2003

Silybin has a potent antibacterial activity, more potent than silymarin II, against gram-positive bacteria without hemolytic activity, whereas it has no antimicrobial activity against gram-negative bacteria or fungi. The mode of action of silybin against the gram-positive bacterial cell was examined by investigating the change in plasma membrane dynamics of bacterial cells using 1 ,6-diphenyl-1,3,5-hextriene (DPH) as a membrane probe and by assessing the inhibition of macromolecular synthesis using radiolabeled incorporation assay. The results showed that silybin inhibited RNA and protein synthesis on gram-positive bacteria.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.719-725
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• 2011

To apply TMAH-based Py-MS to a field biological detection system for real-time classification of cell-type, reproducible patterns of the TMAH-based Py-MS spectra was known as a critical factor for classification but was seriously disturbed by quantity of cells injected into pyro-tube. This factor is an exterior variable that could not be complemented by improving the performance of the TMAH-based Py-MS instrument. One of idea to solve the knotty problem has been flashed from "Top-down proteomics for identification of intact microoganisms". That is, biomarker peaks are selected from complicate Py-MS spectra for intact microoganisms by tracing out their origins, based on Py-MS spectra for the featured components of different cell-types, in Top-down approach. This idea has been tested in classification of different Gram-type microoganisms. Through the analyses of spectra for the featured components - peptidoglycan and lipoteichoic acid for Gram-positive cells and lipopolysaccharide and lipid A for Gram-negative cells - with comparing to the spectra the corresponding Gram-type cells in the Top-down approach, biomarker peaks were selected to carry out PCA(Principal Component Analysis) in order to see classification of different Gram-types, resulting in significant improvement of their classification. Furthermore, weighting biomarker peaks on intact cell's spectra, based on the data for the featured components of the Gram-types, contributed to elevate classification performance.

• Journal of Environmental Science International
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• v.16 no.11
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• pp.1295-1300
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• 2007

The antibacterial effects of anodic electrolyzed water against various bacteria were studied in this investigation. Complete inactivation of Gram-positive and Gram-negative bacteria occurred within 15 s after exposure to anodic electrolyzed water. Moreover, 1/2, 1/5 and 1/10 diluted anodic electrolyzed water by adding deionized water showed strong antibacterial effects. However, the inhibitory effect of anodic electrolyzed water on the anaerobe of Propionibacterium acnes was much weaker than that on the aerobes, including Gram-positive and Gram-negative bacteria. The degraded fragments of E. coli cell were observed upon treating anodic electrolyzed water for 1 min by using scanning electron microscopy.

• Applied Biological Chemistry
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• v.17 no.2
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• pp.117-124
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• 1974

The 23 representative bacteria were studied for the glucosamine contents which represent the glycolipid content of the cell wall. The distribution of glycolipid in various bacteria was examined and the relationship between the glycolipid contents and the Gram stain was elucidated. The results were as follows: 1. The contents of glucosamine in the glycolipid of Gram negative and variable bacterial cell wall were large ranging from the least 0.04 ${\mu}g$ of Proteus vulgaris to the largest 2.48 ${\mu}g$ of Aerobacter aerogenes. The Gram positive bacteria and only those Gram positive among Bacilli contained less than 0.02 ${\mu}g$ of glucosamine contents. The least glucosamine containing Gram positive bacteria were Corynebacterium sepedonicum and Staphylococcus aureus. It could generally be said that the Gram negative and variable bacteria contain the higher content of glucosamine in the cell wall than the positives. 2. The bacteria were better stained by the Gram solution after the extraction of glycolipid from the cell wall than those without extraction. 3. The four infrared spectra of glycolipids obtained from Aerobacter aerogenes, Bacillus circulans, Pseudomonas fluorescens, and Salmonella typhirurium showed all the similar characteristics. All showed the existence of groups; OH, C-O, C-O-C, $CH_2+CH_3$, amide band, fatty acid ester band and ester carbonyl bond.

• Food Science of Animal Resources
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• v.37 no.4
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• pp.502-510
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• 2017

This study investigated bacterial growth-inhibitory effect of 69 therapeutic herbal plants extracts on 9 bacterial strains using a disc diffusion assay. Especially, the antimicrobial activity of Psoraleae semen, which showed different activity on pathogenic Gram-positive and Gram-negative bacteria, was evaluated by MIC (minimal inhibition concentration) and biofilm formation assay. The effect of Psoraleae semen extract on bacterial cell membranes was examined by measurement of protein leakage (optical density at 280 nm) and scanning electron microscope (SEM). No clear zone was formed on discs containing Gram-negative bacteria, but Gram-positive bacteria exhibited clear zones. The MICs of Psoraleae semen extract were $8{\mu}g/mL$ for Streptococcus mutans, and $16{\mu}g/mL$ for Enterococci and Staphylococcus aureus. In addition, biofilm formation was inhibited at concentration $8-16{\mu}g/mL$. Protein leakage values and SEM images revealed that cell membranes of Gram-positive bacteria were impaired following exposure to the extract. Further, the extract inhibited the growth of Listeria monocytogenes in sausages. These results indicate that Psoraleae semen extract could be utilized as a natural antimicrobial agent against Gram-positive bacteria.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1341-1348
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• 2019

Acetic acid is indirectly involved in cell center metabolism, and acetic acid metabolism is the core of central metabolism, affecting and regulating the production of bacteriocin. Bacteriocin is a natural food preservative that has been used in the meat and dairy industries and winemaking. In this paper, the effects of acetic acid on bacteriocin produced by Gram-positive bacteria were reviewed. It was found that acetic acid in the undissociated state can diffuse freely through the hydrophobic layer of the membrane and dissociate, affecting the production, yield, and activity of bacteriocin. In particular, the effect of acetic acid on cell membranes is summarized. The link between acetic acid metabolism, quorum sensing, and bacteriocin production mechanisms is also highlighted.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.1
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• pp.39-47
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• 2009

Gaegurin 4(GGN 4), an antimicrobial peptide isolated from a Korean frog, is five times more potent against Gram-positive than Gram-negative bacteria, but has little hemolytic activity. To understand the mechanism of such cell selectivity, we examined GGN4-induced $K^+$ efflux from target cells, and membrane conductances in planar lipid bilayers. The $K^+$ efflux from Gram-positive M. luteus(2.5 ${\mu}g/ml$) was faster and larger than that from Gram-negative E. coli(75 ${\mu}g/ml$), while that from RBC was negligible even at higher concentration(100 ${\mu}g/ml$). GGN4 induced larger conductances in the planar bilayers which were formed with lipids extracted from Gram-positive B. subtilis than in those from E. coli(p<0.01), however, the effects of GGN4 were not selective in the bilayers formed with lipids from E. coli and red blood cells. Addition of an acidic phospholipid, phosphatidylserine to planar bilayers increased the GGN4-induced membrane conductance(p<0.05), but addition of phosphatidylcholine or cholesterol reduced it(p<0.05). Transmission electron microscopy revealed that GGN4 induced pore-like damages in M. luteus and dis-layering damages on the outer wall of E. coli. Taken together, the present results indicate that the selectivity of GGN4 toward Gram-positive over Gram-negative bacteria is due to negative surface charges, and interaction of GGN4 with outer walls. The selectivity toward bacteria over RBC is due to the presence of phosphatidylcholine and cholesterol, and the trans-bilayer lipid asymmetry in RBC. The results suggest that design of selective antimicrobial peptides should be based on the composition and topology of membrane lipids in the target cells.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.244-248
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• 1987

Attempts were made to enumerate the number of Gram positive and negative bacteria in the development of natural fermentation rapidly and simultaneously. A general Gram stain was applied to this study. The number of cells by Gram stain was proportional to the cell turbidity by spectrophotometer within a range of 0.7 absorbance at 610nm. The cells washed out during procedures were not exceeded about 8 percentage. The standard error of separate counts in the mixture of Cscherichia coli and Micrococcus luteus was $5.1\pm2.3$%. The possible range of counting was $5.5\times 10^{7}-1.0\times 10^{9}$ cells/ml. Therefore, it is believed that a general Gram stain could be applied to the separate counting of mixture of Fram positive and negative bacterial populations too. In practice, growth kinetics of hemp retting and Kimchi fermentation were presented.

• Korean Journal of Veterinary Service
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• v.20 no.2
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• pp.151-159
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• 1997

This study was carried out to isolate of causative agents from CMT-positive and mean somatic cell count(SCC) $\geq$500,000 cells/ml mastitic milk, and evaluate to antimicrobial susceptibility of isolates in Iksan branch area from January to November, 1996. 1. The CMT-positivity(SCC 500,000 cells/ml) of 610 heads was 36.2% (221), and of 2,373 quarter milks was 16.1% (383). 2. The Gram-positive isolates were 153 strains which was Staphylococcus sp (115), Micrococcus sp (18), Streptococcus sp (10), Listeria monocytogenes (5) and Enterococcus faecalis(5). 3. The Gram-negative isolates were 66 strains including E coli(14), Yersinia sp (13), Shigella sp(8), Enterobacillus sp(8), Cedecea sp(5), Pseudomonas aeruginosa(5), Proteus sp(5), Klebsiella sp(4), Salmonella sp(2), kluyvera ascorbate(1) and Tatumella ptyseos (1). 4. The Gram positive strains of isolates were moderately susceptible to T/s, Cp, Fd, Imp, Aug, Rif, Cft and Va. And the Gram negative strains of Isolates were moderately susceptible to T/s, Cp, Imp, Pi and Ti, In order. 5. Multiple antimicrobial resistant patterns were encountered 62 and 36 from Gram positive and negative isolates, respectively.