• Food Science and Preservation
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• v.15 no.2
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• pp.300-305
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• 2008

We investigated an antibacterial substance produced by Bacillus subtilis HS 25. Antibacterial activity was relatively heat-stable, with no effect caused by heating at $100^{\circ}C$ for 10 min, but a gradual decrease in activity after 15 min at $100^{\circ}C$. The antibacterial substance was more stable at pH 7.42-12 than at pH 4.5-5.0. There was strong antibacterial activity against E. coli and P. mirabilis at pH 12. The minimum inhibition concentration (MIC) of the substance was 5 mg/mL for E. coli 7.5 mg/mL for P. mirabilis and S. aureus and 15 mg/mL for S. enteritidis, K. pneunoniae, and V. parahaemolyticus. When the substance was added to cultures of E. coli, S. enteritidis, and P. mirabilis, the bacterial surfaces became irregular and deeply changed. The substance produced from B. subtilis HS 25 was not degraded by Papain but was degraded by a protease from Aspergillus orzae, pancreatin, and pepsin.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.444-454
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• 2016

Sixteen lactic acid bacterial strains were isolated from silage and cow dung samples, and characterized to identify their potential as silage additives. They were identified as the members of the genera Lactobacillus, Enterococcus, and Weissella, and clustered into nine groups based on the sequences of the genes for 16S rRNA, RNA polymerase alpha subunit, 60-kDa heat shock protein, and phenylalanyl-tRNA synthase alpha subunit. Among them, the three strains which were genetically similar to L. plantarum showed the fastest growth and pH decrease in MRS and rye extract media, the highest numbers of available carbohydrates, and the widest ranges of pH, temperature, and salinity for growth. In addition, they showed no amplified DNA products in the PCR examination targeting the genes for the production of biogenic amines, and the MRS media where they had been cultured showed relatively high inhibition effect against the growth of silage-spoiling microorganisms, including fungi, yeast, and clostridia. The results suggest that these strains are good candidates for silage additives. However, the rye extract media where the lactic acid bacteria had been cultured had no effect on or stimulated the growth of the silage-spoiling microorganisms, and the causes must be established for the practical use of the lactic acid bacteria as silage additives.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.3
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• pp.255-262
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• 1992

In vitro digestibility of filefish, protein was substantially decreased by fiber constituents in the follow-ing order : pectin (9.97%), gum karaya (7.03%), sodium alginate (6.12%),and cellulose (1.52%). The order of reduction by fibrous residues from vegetables ranked as follows : sea tangle (12.36%), Ro-maine lettuce (11.12%), perillar leaf (8.96%), and green pepper (5.15%). The inhibitory effect of the dietary fibers towards filefish protein digestion, expressed as soybean trypsin inhibitor equivalents, in-creased with added levels, but the inhibition differed with the sources of dietary fibers. Sea tangle and sodium alginate were most active in decreasing the concentration of essential amino acid from filefish protein hydrolysis. Sodium alginate exerted an inhibitory effect on the activity of trypsin, but the other fiber constituents did not have an inhibitory potency on trypsin and bacterial pretense (Streptomyces griceus). Results supported that dietary fiber components may reduce protein digestibility through the interaction of dietary fiber components with filefish protein.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.69-79
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• 2003

The purpose of this present study was to develop a new way of self-curing acrylic resin, using commercially available polyphosphate, Calgon, which is known to be antimicrobial and safe. For the study, polyphosphate(polyP) was blended with acrylic powder and devided into four groups as follows: no polyP(control), 1% polyP, 2% polyP, and 3% polyP. For the experiment, Streptococcus mutans GS5, Streptococcus sobrinus 6715, Streptococcus gordonii G9B and Challis, Porphyromonas gingivalis 2561, and Candida albicans ATCC 90027 were used. Resin specimens in each group were tested in vitro for the purpose of investigating the effect of polyP on the microbial attachment, growth and hydrophobicity of the resin surface. The results were as follows. 1. PolyP added to the acrylic resin decreased attachment of S. mutans GS5, S. sobrinus 6715, S. gordonii G9B. The greater binding inhibition was found in acrylic resin polymerized with polyP at higher concentrations. 2. The addition of polyP to acrylic resin failed to significantly affect the growth of the tested microorganisms. 3. The addition of polyP to acrylic resin seemed to reduce hydrophobicity of the acrylic resin. PolyP in acrylic resin does not seem to exert a direct antibacterial activity, but rather inhibit attachment of oral bacteria, especially mutans streptococci to saliva-coated acrylic resin. The acrylic resin reduces attachment of streptococci may be due to the decreased hydrophobicity caused by polyP added to the resin. PolyP may be included to acrylic resin to inhibit dental caries which often occurs when removable acrylic resin appliance is placed.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.736-742
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• 1996

This study was carried out to investigate the effect of the lactoperoxidase (LP) system on the acid production of gel type yogurt. The LP system was activated by adding freshly prepared solutions of 1 ppm (v/w) lactoperoxidase and three different concentrations (0.125 mM, 0.25 mM, 0.5 mM) in equimolar ratios of KSCN and $(H_{2}O_{2}$, In 0.25 mM treated samples for the 4 hr fermentation resulted in titratable acidity of $0.4{\%}$, pH of 5.06, lactic acid bacterial count of $3.0{\times}10^{8}\;CFU/ml and acetaldehyde concentration of 10.2 ppm, whereas the untreated samples were 1.0%, 4.54, $4.7{\times}10^{9}\;CFU/ml and 18.0 ppm, respectively. The residual amount of KSCN in 0.25 mM treated samples was determined during the experiments, which decreased to 4.4 ppm. There was no detectable $(H_{2}O_{2}$ for 6 hr fermentation. However, residual KSCN and $(H_{2}O_{2}$ concentrations in 0.5mM treated samples were 5.7 and 8.4 ppm, respectively. These results have indicated that the optimum concentration of $(H_{2}O_{2}$ and KSCN to activate the LP system was 0.25 mM each.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.331-338
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• 2014

Cystatins (CSTs) are reversible and competitive inhibitors of C1A cysteine proteases, corresponding to papain-like cathepsins in plants and animals. A viral CST (CpBV-CST1) was identified from a polydnavirus, Cotesia plutellae bracovirus (CpBV). Our previous study indicated that a transient expression of CpBV-CST1 interfered with immune response and development of Plutella xylostella larvae. To directly demonstrate the protein function, this study produced a recombinant CpBV-CST1 protein (rCpBV-CST1) using bacterial expression system to determine its inhibitory activity against cysteine protease and to assess its physiological alteration in insect immune and development. The open reading frame of CpBV-CST1 encodes a polypeptide of 138 amino acids (${\approx}15kDa$). rCpBV-cystatin protein in BL21 STAR (DE3) competent cells containing a recombinant pGEX4T-3:CpBV-CST1 was over-expressed by 0.5 mM IPTG for 4 h. In biological activity assay, the purified rCpBV-CST1 showed a significant inhibition against papain activity. It inhibited a cellular immune response of hemocyte nodule formation in the beet armyworm, Spodoptera exigua. Moreover, its oral administration retarded larval development of the diamondback moth, Plutella xylostella in a dose-dependent manner. These results suggest that CpBV-CST1 may be applied to control insect pest populations.

• Journal of Food Hygiene and Safety
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• v.17 no.1
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• pp.26-30
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• 2002

A bacterium isolated from contaminated white ginseng was indentified by using API kit and electron microscope. The isolate was determined as rod shaped bacterium having 0.6-1.0 ${\mu}{\textrm}{m}$ in diameter and 1.2-3.0 ${\mu}{\textrm}{m}$ in length. It had motility by flagellum. The isolate had $\beta$-galactosidase, arginine dihydrolase and omithin decarboxylase. It used citrate as sole carbon source but not produced H$_2$S. It also fermented glucose, manitol, sorbitol, rhamnose, sucrose, melibiose, arabinose and amygdalin. The isolate was identified as Enterobacter sp by the above API kit analysis and electron microscopy observation. Ginseng saponin was added to culture of Enterobacter sp. in order to investigate saponin's influence on its growth. The strain was incubated at 38$^{\circ}C$ for 3 days after addition of 0.05, 0.5, 2.0 and 4.0% (w/v) of saponin, respectively and the growth rates were investigated. The relative bacterial growth rates showed 75.0, 37.5, 7.5 and 0.5%, respectively, when compared with 100% of saponin non-added group. These results suggest that the growth of Enterobacter sp. is inhibited by saponin with the concentration dependency.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.569-576
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• 2007

Four hundred and fifty tilapias ($6.77{\pm}0.23$ g) were assigned randomly to six groups to evaluate the feasibility of the tested antibacterial peptides (ABPs) and oligosaccharides as substitutes for antibiotics. The control group was fed with a commercial tilapia diet; other five groups were fed with the same commercial diet supplemented with konjac glucomannan (KGLM), cluster bean galactomannan (CBGAM), and three animal intestinal ABPs derived from chicken, pig and rabbit at 100 mg/kg respectively. After 21 days of feeding, growth, disease resistance, and in vivo anti-adherence were determined. Furthermore, the inhibitory effect of tested agents on adhesion of Aeromonas veronii biovar sobria (A.vbs) strain BJCP-5 to tilapia enteric epithelia in vitro was assessed by cell-ELISA system. As a result, the tested agents supplemented at 100 mg/kg show significant benefit to tilapia growth and disease resistance (p<0.05), and the benefit may be correlated with their interfering in the contact of bacteria with host mucosal surface. Although none of the tested agents did inhibit the growth of BJCP-5 in tryptic soy broth at $100{\mu}g/ml$, all of them did inhibit the adhesion of A.vbs to tilapia enteric epithelia in vivo and in vitro. In vitro mimic assays show that three ABPs at low concentrations of $25{\mu}g/ml$ and $2.5{\mu}g/ml$ have the reciprocal dose-dependent anti-adherence effect. The inhibition of ABPs may be correlated with a cation bridging and/or receptor-ligand binding, but not with hydrophobicity. The KGLM and CBGAM inhibited the adherence of BJCP-5 to tilapia enteric epithelia with dose-dependent manner in vitro, and this may be through altering bacterial hydrophobicity and interfering with receptor-ligand binding. Our results indicate that the anti-adherence of the tested ABPs and oligosaccharides may be one of the mechanisms in promoting tilapia growth and resistance to A.vbs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3383-3387
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• 2015

Portulaca oleracea (Family: Portulacaceae), is well known for its anti-inflammatory, antioxidative, anti-bacterial, and anti-tumor activities. However, cytotoxic effects of seed oil of Portulaca oleracea against human liver cancer (HepG2) and human lung cancer (A-549) cell lines have not been studied previously. Therefore, the present study was designed to investigate the cytotoxic effects of Portulaca oleracea seed oil on HepG2 and A-549 cell lines. Both cell lines were exposed to various concentrations of Portulaca oleracea seed oil for 24h. After the exposure, percentage cell viability was studied by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT), neutral red uptake (NRU) assays, and cellular morphology by phase contrast inverted microscopy. The results showed a concentration-dependent significant reduction in the percentage cell viability and an alteration in the cellular morphology of HepG2 and A-549 cells. The percentage cell viability was recorded as 73%, 63%, and 54% by MTT assay and 76%, 61%, and 50% by NRU assay at 250, 500, and $1000{\mu}g/ml$, respectively in HepG2 cells. Percentage cell viability was recorded as 82%, 72%, and 64% by MTT assay and 83%, 68%, and 56% by NRU assay at 250, 500, and $1000{\mu}g/ml$, respectively in A-549 cells. The 100 $100{\mu}g/ml$ and lower concentrations were found to be non cytotoxic to A-549 cells, whereas decrease of 14% and 12% were recorded by MTT and NRU assay, respectively in HepG2 cells. Both HepG2 and A-549 cell lines exposed to 250, 500, and $1000{\mu}g/ml$ of Portulaca oleracea seed oil lost their normal morphology, cell adhesion capacity, become rounded, and appeared smaller in size. The data from this study showed that exposure to seed oil of Portulaca oleracea resulted in significant cytotoxicity and inhibition of growth of the human liver cancer (HepG2) and human lung cancer (A-549) cell lines.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.3
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• pp.378-384
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• 2007

Three microorganisms and one chemical preservative were tested for their effects on the fermentation and aerobic stability of whole-crop wheat, sorghum and maize silages. Wheat at the early dough stage, sorghum at the late milk stage and maize at the one-third milk line stage were harvested and ensiled in 1.5-l anaerobic jars untreated or after the following treatments: control (no additives); Lactobacillus plantarum (LP) at $1.0{\times}10^6$ colony-forming units (CFU)/g of fresh forage; L. buchneri (LB) at $1.0{\times}10^6$ CFU/g; Propionibacterium acidipropionici (PA) at $1.0{\times}10^6$ CFU/g; and a formic acid-based preservative (FAP) at 3 ml/kg of fresh forage weight. Three jars per treatment were sampled on d 90 after ensiling, for chemical and microbiological analysis. At the end of the ensiling period, 90 d, the silages were subjected to an aerobic stability test lasting 5 d. In this test, $CO_2$ produced during aerobic exposure was measured along with chemical and microbiological parameters which serve as spoilage indicators. The silages inoculated with LP had higher concentration of lactic acid compared with the controls and the other treated silages (p<0.05). The controls and LP-inoculated silages spoiled upon aerobic exposure faster than LB, PA and FAP-treated silages. The controls and LP-inoculated silages spoiled upon aerobic exposure faster than LB, PA and FAP-treated silages due to more $CO_2$ production (p<0.05) in these two groups and development of yeasts unlike the other groups. In the experiment, the silages treated with LB, PA and FAP were stable under aerobic conditions. However, the numbers of yeasts was higher in the LP-inoculated wheat, sorghum and maize silages compared with the LB, PA and FAP-treated silages. The LB, PA and FAP improved the aerobic stability of the silages by causing more extensive heterolactic fermentation that resulted in the silages with high levels of acetic and propionic acid. The use of LB, PA and FAP as silage additives can improve the aerobic stability of whole-crop wheat, sorghum and maize silages by inhibition of yeast activity.