• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.23-28
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• 1990

Effect of lauric acid and whir derivatives on the growth of Bacillus subtilis var niger was studied. Lauric acid showed the strongest inhibition among the fatty acids tested, Lysis rate of lauric acid proved to be greatly sensitibility against logarithmic phase cells but was not so influenced by cell concentration. On the other hand, lauric acid was inhibited lysis activity when the pH shift from 7.0 to 5.5

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.849-859
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• 2000

This study was conducted to identify the characteristics of methane fermentation and lysis effects of pre-treated microalgae. Chemical compositions of microalgae showed that the VS(volatile solid) was 86.1% of TS(total solid), and the protein was 63.5% of VS. These values were higher than those of activated sludge. The cell lysis test of raw microalgae biomass was conducted by many physicochemical methods. presenting that the degree of cell lysis was affected by following order: ultrasonic(100min.), alkali(pH 13), ultrasonic(10min), thermal($120^{\circ}C$), thermal($50^{\circ}C$), and acidic(pH 3) treatment. Methane fermentation with many pre-treated samples was performed, showing that the concentration of acetic acid was the highest. followed by propionic acid, butylic acid and valerie acid among all VFA(volatile fattic acid). In methane production. ultrasonic samples were only more effective than untreated one in total gas and methane productivity. but other samples were less effective. Especially. the alkalic sample had an inhibitation effect on methanogens.

• Bulletin of the Korean Chemical Society
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• v.18 no.7
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• pp.761-766
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• 1997

Phospholipase C from Clostridium perfringens is known to catalyze the hydrolysis of phospholipids in biological membranes. In this study, a simple and sensitive method for assaying phospholipase C was developed by using liposomes entrapping calcein as a fluorescent marker. Phospholipase C-induced lysis of liposomes was determined by measuring the fluorescence intensity of calcein released out from liposomes, Various liposomes with different compositions were prepared by reverse-phase evaporation method to investigate the effect of liposomal composition on the lytic activity of phospholipase C. The calcein-entrapping efficiency of liposomes was affected by the chain length of fatty acid in phosphatidylcholine constituting liposomes. The lytic activity of phospholipase C was the highest against liposomes prepared with eggPC. The lytic activity decreased with increasing chain length of fatty acid in phosphatidylcholine. Incorporation of cholesterol more than 20% into the liposomal bilayer inhibited the phospholipase C-induced lysis. The lysis of liposomes was more greatly increased by the addition of 10 mM of calcium. The lytic activity of phospholipase C was also affected by the surface charge of liposomes. Taken together, it was concluded that reverse-phase evaporation vesicles composed of dipalmitoylphosphatidylcholine and cholesterol in the molar ratio of 9 : 1 allowed to detect the lowest concentration of phospholipase C (0.10 μg/assay volume). This study suggested that the use of liposomes can provide a simple, sensitive and inexpensive method for assaying phospholipase C.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.157-162
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• 2007

Lactic acid bacteria (LAB) has been regarded as a useful microorganism and tried to manipulate plasmid DNA for increasing the usefulness. Although several methods have been developed to isolate plasmid DNA from Escherichia coli (E. coli), these methods were not sufficient to apply to LAB with exception of O'Sullivan's lysis method. So, we evaluated plasmid DNA extraction from LAB using general E. coli preparation methods and tried to improve the extraction yield and DNA purity by modifying O'Sullivan's alkaline lysis method. To improve the extraction yield, salt and carrier were added to precipitant and those were incubated at $-70{^{\circ}C}$. Only incubation at $-70{^{\circ}C}$ was the effective method of those modifications. Purity of plasmid DNA was improved by two times of each centrifugation and phenol/chloroform extraction. However, DNA was damaged by twice extraction with phenol/chloroform. Also, exclusion of ethidium bromide showed negative effect to purity. Additionally, it was recommended that improvement of the extraction yield may be due to centrifugation at high speed for more time and to dissolving complete DNA pellet before addition of 7.5 M ammonium acetate. Extraction using this modification produced higher quality of plasmid DNA.

• The Journal of the Korean dental association
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• v.11 no.8
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• pp.525-530
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• 1973

True collagenolytic enzymes in animal tissues were first demonstrated by Gross and Lapiere (1962), who showed the ability of such an enzyme in the culture medium of living explants of tadpole tissue to degrade a specific substrate of undenatured collagen under physiological conditions. Recently, tumor-associated collagenolytic activity has been demonstrated in human neoplasm and in ascites V Carcinoma. This investigation have been peforme to determine whether or not a collagen lytic enzyme could e found in isolated solid Tawa sarcoma of Donryu female rat obtained the culture medium. The results were as follows. 1. 11.5mg% of hydroxyproline contained in Donryu rat skin collagen, which was extracted by 0.5M acetic acid. 2. Cultivation of solid Tawa sarcoma tissues on reconstituted rat skin collagen gels showed lysis of adjacent gel after 18 hours, and much more extensive lysis after 5 days. 3. Collagen substrate was not attacked by the common proteolytic enzymes, trypsin, pepsin, and pronase.

• Toxicological Research
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• v.4 no.2
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• pp.95-105
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• 1988

The effects of polyacetylenes on living membrances, rat erythrocyte and murine leukemic L1210 cell as well as artificial lipid bilayer were determined to investigate the cytotoxic mechanism of polyacetylenes against cancer cell lines. As results, panaxydol and panaxynol caused erythrocyte hemolysis dose-dependently while panaxytriol had no lysis. For liposomes composed of phosphatidyl choline (PC) and phosphatidic acid(PA), all three polyacetylenes supressed the osmotic behavior at the same degree.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.973-978
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• 2001

The bacterial flagellar motor is a molecular machine that couples proton or sodium influx to force generation, mostly for driving rotation of the helical flagellar filament. In this study, we cloned a gene (motX) encoding a component of the sodium-driven flagellar motor from Vibrio fluvialis. The nucleotide sequence of the motX gene, composed of 633 bp and 211 amino acid residues, was determined. Overexpression of the motX gene in Escherichia coli using a strong promoter induced growth inhibition and cell lysis. The lethal effect of E. coli was suppressed by adding amiloride, as a potent inhibitor for the sodium channel. Electron microscopic observation of the expressed protein indicated that MotX protein induced by isopropyl ${\beta}$-D-thiogalactopyranoside caused the lysis of host cell.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.467-471
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• 1986

Yeast cell wall lytic enzyme was purified from Fusarium moniliforme by ammonium sulfate fractionation and gel column chromatography. The lytic activity was found to consist of three enzyme activities which were resolved on Sephadex G-100. The first peak on chromatogram exhibited proteolytic, lytic and laminarinase activities, and the second had both lytic and laminarinase activities, whereas the third peak was shown to contain lytic activity only. Three enzyme activities showed the synergistic effect and reducing agents accelerated the yeast roil wall lysis. This indicates that lytic, proteolytic and laminarinase activity acted cooperatively in the lysis of intact cells. Tannic acid precipitate of crude enzyme constituted of three enzyme activities had a high lytic activity on viable yeast cell and has proved useful in yeast protoplast formation.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.289-296
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• 1985

A simple procedure for rapid isolation of plasmid DNA from lactobacillus species and streptococcus species is described. Lactic acid bacteria were cultured in the TCM broth containing 0.5％ glycine and plasmid DNA was isolated from cells treated with mutanolysin by alkaline-detergent lysis method. Good results for releasing and isolating plasmid DNA from lactobacillus species were obtained by treatment of cells with 30$\mu\textrm{g}$ of mutanolysin per ml at 37$^{\circ}C$ for 5 to 10 min. For the streptococcus species, the optimum conditions were slightly different. The procedure could be used for rapid characterization of plasmid DNA in Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus helveticus, Streptococcus lactis, Streptococcus faecalis, Streptococcus faecium, and Streptococcus cremoris strains. Using this procedure, plasmids isolated from $1.5m\ell$ cultures could readily be visualized in agarose gel.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.269-277
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• 1996

Bacteriocins are proteins produced by a heterogeneous group of bacteria that have a bactericidal effect on closely related organisms. Recently, bacteriocins from lactic acid bacteria and other food-related organisms have been the subject of much research because of their potential as food biopreservatives. Various modifications of agar plate diffusion assays are the most widely used methods even though the limitations of such assays are generally recognized. The ability to obtain a concentrated crude preparation on bacteriocin by optimizing production parameters greatly simplifies recovery of bacteriocin on subsequent purification steps. Some studies performed to optimize bacteriocins have been purified to homogeneity, and the amino acid sequences of many of these purified bacteriocins have been determined. Obtaining characterization data on purified bacteriocin will minimize the risk of overlapping of research and confusion on identification of these compounds. Several me-chanisms leading to cell death have been hypothesized. These include depletion of the proton motive force(PMF) across the cell membrane: RNase and/or DNase activity within the sensitive cell; and pore formation and lysis of sensitive cells at the cell membrane.