• Journal of Life Science
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• v.34 no.8
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• pp.576-587
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• 2024

In this study, diverse bacterial strains were isolated from fermented foods to screen those with antibacterial activity. Among them, one strain, identified as Bacillus vallismortis MCBL 1012 through 16S rRNA gene sequence analysis, was selected for its bacteriocin production. The culture supernatant of B. vallismortis MCBL 1012 showed antibacterial activity, mainly against Gram-positive bacteria. Scanning electron microscopy (SEM) revealed that bacteriocin treatment led to cellular content leakages in Listeria monocytogenes KCCM 40307, Enterococcus faecium KCCM 12118, and Streptococcus mutans KCTC 3065. PCR analysis confirmed B. vallismortis MCBL 1012 harbored subtilosin A gene (sbo A). Antibacterial activity was decreased by proteolytic enzymes like proteinase K, subtilisin A, and α-chymotrypsin. The bacteriocin demonstrated stability at 40℃ and 60℃ for 120 min, and up to 80℃ for 60 min, with rapid activity loss at 100℃. It retained full antibacterial activity within a pH range of 4.0 to 8.0 and was not affected by up to 100% organic solvents like ethanol, methanol, acetonitrile, and tetrahydrofuran. Nevertheless, activity decreased with more than 40% isopropanol and 80% acetone. Most tested inorganic salts and detergents had no effect on antibacterial activity except, CuSO₄ and NiSO₄ at specified concentrations. The bacteriocin exerted its antibacterial effect through bactericidal action against L. monocytogenes KCCM 40307. The bacteriocin was purified by ammonium sulfate precipitation, DEAE anion exchange chromatography, and RP-HPLC. The purification resulted in a final yield of 0.03% and a 283.7-fold increase in specific activity. MALDI-TOF MS analysis determined the exact molecular weight of purified bacteriocin to be 3,326.1 Da.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.76-82
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• 2009

Wheat is the most widely cultivated cereal and an important source of dietary protein worldwide. Wheat allergy, defined as an adverse immunologic reaction to wheat, encompasses a broad spectrum of disorders with different pathomechanisms and clinical manifestation. The Nuruk, a traditional Korean Koji for brewing, was made with wheat flour and fermenting microbes such as bacteria, yeast and mold. The strains grown on Nuruk secrete various enzymes as amylase and protease. By the activation of such enzymes, starch and proteins in Nuruk are hydrolyzed to sugar and amino acid. Therefore, it is supposed to reduce allergic proteins in wheat. To study quality properties and degradation degree of allergenicity in Nuruk by fermentation, we investigated the changes of general ingredients and allergenicity in Nuruk during fermentation. Moisture contents was decreased from 24.2% to 13.6% during fermentation. Crude lipid and protein contents were gradually increased during fermentation. After 15 days of fermentation, reducing sugar and total sugar contents were reached its maximum level, and they were 27.45% and 39.00%, respectively. Acid and neutral protease activity were significantly increased during fermentation, but alkaline protease activity was not detected. ${\alpha}$-amylase activity was gradually increased and showed maximum level about 2,833.00 U/g after 15 days of fermentation. Glucoamylase activity was the highest level about 497.9 U/g after 10 days of fermentation. The increase of these proteolytic and saccharogenic enzyme activities will provide efficient condition for production of rice wine. Also, protein fractions were isolated from Nuruk, and degradation of these proteins during fermentation were confirmed by SDS-PAGE. IgE immunoblotting using patient's sera with wheat allergy was performed to confirm allergenic protein in Nuruk. These results as fermentation of Nuruk will provide a useful tool for developing safer wheat products to prevent wheat allergy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.307-314
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• 2006

This study was conducted to screen in vitro angiotensin converting enzyme (ACE) inhibitory activities of methanol (MeOH) and aqueous extracts which were prepared by four different extractions-80% methanol extracts(ME) at $20^{\circ}C\;and\;70^{\circ}C$, respectively and aqueous extracts (AE) at both temperatures with the residue of the MEs-of ten marine green algae and nineteen brown algae collected along Jeju coast of Korea. Most marine brown algae extracts showed higher capacities than those of marine green algae in ACE inhibitory activity. Particularly, $70^{\circ}C$ MeOH extract (70ME) of Hizikia fusiforme showed the strongest inhibition activity (about 87%) among all the extracts. Also, 70 MEs of Enteromorpha linza, Ishige sinicola, Laminaria ochotensis, Petrospongium rugosum, Sagrassum horneri, Undaria pinnatifida and $20^{\circ}C$ MeOH extracts (20ME) of Myagropsis myagroides, Petrospongium rugosum, $20^{\circ}C$ aqueous extracts (20AE) of Codium contractum, Enteromorpha compressa, and $70^{\circ}C$ aqueous extracts (70AE) of Ecklonia cava, Petrospongium rugosum showed moderate ACE inhibitory activities more than 50% and the other extracts exhibited weak activities. On tile other hand, E. cava had the best ACE inhibitory activity among 70AEs. This indicates that 70AE of E. cava contains potential anti-ACE macromolecular. We tried to proteolytic digest 70AE of E. cava to induce production of anti-ACE peptides from E. cava 70AE. The enzymes used are five pretenses including Kojizyme, Flavourzyme, Neutrase, Alcalase, and Protamex, which are food grade-commercial enzymes from Novo Co. Flavourzyme-digest of E. cava 70AE showed the highest inhibitory activity about 90%. And the five different enzymatic digests of the E. cava 70AE ranged from 2.33 to 3.56 ${\mu}g/mL$, respectively in $IC_{50}$ values of anti-ACE activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1446-1451
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• 2010

Silk sericin protein was hydrolyzed by seven proteolytic enzymes to examine the effectiveness of the hydrolysates to bind iron. The amino acid nitrogen contents of hydrolysates by Flavourzyme were higher than the others enzymes, and its iron binding capacity showed dose-dependent increase. The bioavailability of iron binding peptide from sericin hydolysates was investigated in iron-deficient rats. Three-week-old male rats were fed iron-deficient diet for three weeks. Rats were divided into four groups (DD: no treated group on iron deficient diet, DD+HI: heme-iron treated group, DD+OI: sericin-Fe, and DD+II: inorganic iron ($FeSO_4$) treated group, and then iron supplemented by injection for one week. After oral administration for one week, the iron contents of serum and liver were significantly higher in DD+OI ($4.2\;{\mu}g/mL$ and $80.1\;{\mu}g/mL$) and DD+HI ($3.2\;{\mu}g/mL$ and $70.6\;{\mu}g/mL$) than DD ($2.0\;{\mu}g/mL$ and $47.9\;{\mu}g/mL$). Hemoglobin content of treated groups was significantly higher than DD, but the significant difference among groups was not shown. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not show any significant difference among all groups. Binding iron to peptide from sericin hydolysates seems to improve its bioavailability and to hasten the cure of iron deficiency in experimental rat.

• Journal of Life Science
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• v.22 no.4
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• pp.524-531
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• 2012

Soybean is one of the most common food materials causing food hypersensitivity reactions in Korea. In this study, we have investigated the effect of roasting and fermentation on the allergenicity of soybean. Three kinds of soybean ($Daepung$, $Daewon$, and $Taegwang$) were prepared as raw, roasted, and fermented by $Bacillus$ $subtilis$ GSK 3580, and then their proteins were extracted. The proteins were separated using SDS-PAGE, and the detection of IgE specific to soybean proteins was performed by immunoblotting using 7 sera of soybean allergy patients and non-allergic control individuals. Serum specific IgE to soybean was measured by ELISA. The SDS-PAGE of raw soybean proteins showed various-sized bands ranging from 9 to 76 kDa, which are known as major allergens. In particular, 9, 21, 34, 52, 72, and 76 kDa proteins are known as LTP, Kunits trypsin inhibitor, $Gly$ m Bd 30K, ${\beta}$-subunit, ${\alpha}$-subunit, and ${\alpha}$'-subunit of ${\beta}$-conglycinin, respectively; these are major allergens in soybean. In contrast, only peptides of less than 35 kDa were found in roasted and fermented soybeans. IgE immunoblot analysis of three roasted species of soybeans commonly detected at 38-40 kDa and 10-15 kDa. The protein bands in fermented soybean showed very weak signals or were not detected. In addition, the reactivity of most patients' sera to soybean was decreased after roasting and fermentation. With these results, it may be concluded that the allergenicity of soybeans is reduced by the roasting and fermentation processes. It is supposed that allergenic proteins in soybean were degraded by heat treatment methods and proteolytic enzymes were secreted from fermenting microorganisms.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.256-264
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• 2006

Background: An acute lung injury(ALI) is characterized by the recruitment, activation, and apoptosis of inflammatory cells, numerous products released by inflammatory cells such as reactive oxygen species, inflammatory mediators, and a variety of proteolytic enzymes. It was reported that bacterial infections in diabetics showed impaired PMN functions such as reduced PMN respiratory burst and decreased microbicidal activity in inflamed tissue. However, the effect of the proteinase - inhibitor (MMP-9 vs TIMP-1) in ALI in diabetics is unclear. This study evaluated the differences in the expression of MMP-9 and TIMP-1 after the stimulation of endotoxin in a rat model. Methods: Six-week-old male Sprague-Dawley rats were classified into normal, DM, LPS and DM+LPS groups. The peripheral blood, BAL fluids, and lung tissues were obtained from individual rats. The MMP-9 activity was measured by gelatin zymography and the TIMP-1 level was measured by Western blotting. Results: The total BAL cells of the DM-LPS groups were significantly lower than the LPS groups (p < 0.01). The MMP-9 activities in the serum were higher in the DM+LPS groups than in the other groups. The MMP-9 activities in the BAL fluids were significantly higher in the DM+LPS group than in the normal and diabetic rats (p < 0.05). TIMP-1 expressions in the BAL fluids were significantly lower in the DM+LPS group than other groups (p < 0.05). The ratio between MMP-9 and TIMP-1 in the BAL fluids was significantly higher in the DM+LPS groups (p < 0.05). Conclusion: In ALI in diabetics the higher MMP-9 activity and lower TIMP-1 level are believed to prolonged and intensify the course of inflammation.

• Journal of Food Hygiene and Safety
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• v.23 no.2
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• pp.113-120
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• 2008

The influence of incubation temperature, pH and media components on bacteriocin production by Lactobacillus plantarum K11 were investigated. The highest activity was observed in MRS broth, but no bacteriocin activity was obtained in TSB. The bacteriocin was produced from the exponential growth phase and its activity also reached a maximum in MRS broth, but then dropped after 16 hr because of degradation by extracellular proteolytic enzymes or exhaustion of medium nutrients. The optimal temperature and pH for production of bacteriocin were $37^{\circ}C$ and pH 7.0 in MRS broth, respectively. The addition of 0.5 or 1.0% glucose and $0.5{\sim}1.5%$ lactose to MRS resulted in the increase of the bacteriocin production. With 0.5% NaCl and $K_2HPO_4$, the activities were significantly higher than that of control, respectively. However, increasing nitrogen sources such as beef extract, casein, and tryptone and salts such as $NH_4PO_4$, $MgSO_47H_2O$, and $MnSO_4H_2O$, had detected a negative influence upon the bacteriocin production. Consequently, because the bacteriocin produced by L. plantarum K11 was affected by various incubation conditions, the bacteriocin activity of L. plantarum K11 applied in food as a novel starter will be dependent on environmental factors such as fermentation conditions and food ingredients.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.547-557
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• 1996

Background : An excessive accumulation of neutrophils in lung tissue has been known to play an important role in mediating the tissue injury among the adult respiratory distress syndrome, idiopathic pulmonary fibrosis and cystic fibrosis by releasing toxic oxygen radicals and proteolytic enzymes. Therefore, it is important to understand a possible mechanism of neutrophil accumulation in lung tissue. In many species, exposure to hyperoxic stimuli can cause changes of lung tissues very similar to human adult respiratory distress syndrome and neutrophils are also functioning as the main effector cells in hyperoxic lung injury. The purpose of the present study was to examine whether neutrophils function as a key effector cell and to study the nature of possible neutrophil chemotactic factors found in bronchoalveolar lavage fluid from the hyperoxia exposed rats. Methods : We exposed the rats to the more than 95% oxygen for 24, 48, 60 arid 72 hours and bronchoalveolar lavage(BAL) was performed. Neutrophil chemotactic activity was measured from the BAT- fluid of each experimental groups. We also evaluated the molecular weight of neutrophil chemotactic tractors using fast performance liquid chromatography and characterized the substances by dialyzer membrane and heat treatment. Results : 1) The neutrophil proportions in bronchoalveolar lavage fluid began to rise from 48 hours after oxygen exposure, and continued to be significantly increased with exposure times. 2) chemotactic index for neutrophils in lung lavages from rats exposed to hyperoxia was significantly higher in 48 hours group than in control group, and was significantly increased with exposure time. 3) No deaths occured until after 48 hours of exposure. However, mortality rates were increased to 33.3 % in 60 hours group and 81.3 % in 72 fours group. 4) Gel filtration using fast performance liquid chromatography disclosed two peaks of neutrophil chemotactic activity in molecular weight of 104,000 and 12,000 daltons. 5) Chemotactic indices of bronchoalveolar lavage fluid were significantly deceased when bronchoalveolar lavage fluid was treated with heat ($56^{\circ}C$ for 30 min or $100^{\circ}C$ for 10 min) or dialyzed (dialyzer membrane molecular weight cut off : 12,000 daltons). Conclusion : These results suggested that the generation of neutrophil chemotactic factor and subsequent neutrophil influx into the lungs are playing an important roles in hyperoxia-induced acute lung injury. Neutrophil chemotactic factor in the lung lavage fluids consisted of several distinct components having different molecular weight and different physical characteristics.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.38-43
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• 2005

Matrix metalloproteinase-2 (MMP-2) is a class of proteolytic enzymes that digest collagen type IV and other components of the basement membrane. It plays a key role in the local invasion and the formation of distant metastases by various malignant tumors. The aim of this study was to evaluate the activity of MMP-2 and its significance as a prognostic marker in resected stage I non-small cell lung cancer (NSCLC). Material and Method: In this study we obtained fresh-frozen samples of tumor and non-tumor tissues from 34 patients with stage I NSCLC who underwent resection without preoperative radiotherapy or chemotherapy. After the extraction of total protein from tissue samples, MMP-2 activities were assessed by gelatin-substrate-zymography. The activities were divided into the higher or lower groups. Result: The MMP-2 activities were higher in tumor tissues than in non-tumor tissues. The MMP-2 activity of non-tumor tissues in recurrent group was higher than in non-recurrent group (p<0.01). Also the patients with higher MMP-2 activity of non-tumor tissues showed poor 5 year survival (p<0.01). Conclusion: This result indicates that the higher level of MMP-2 activity in the non-tumor tissue is associated with the recurrence and survival after the resection of stage I NSCLC. Therefore, MMP-2 activity in the non-tumor tissue could be used as a potential prognostic marker for the resected stage I-NSCLC.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.97-104
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• 2002

Protein hydrolysate was prepared as a natural flavor stock from the sharp toothed eel (Muraenesox cinereus) mince using com-mercially available proteolytic enzymes, Alcalase, Neutrase, Protamex, and Flavourzyme. A 6 hr hydrolysis of mince, to which water of the equal weight of the mince was added, with $2\%$ (w/w, protein weight) Elavourzyme at $50^{\circ}$ yielded a hydrolysate of the highest acceptability. Removing the access lipid in liquified hydrolysate (not dehydrated) after enzyme hydrolysis, five times repetitive extraction using n-hexane (liquified hydrolysate : n-hexane=4 : 1, v/v) was effective, resulting in less than $1\%$ lipid content of the dehydrated-hydrolysate. The amino acid composition of the hydrolysate (prepared with Flavourzyme) was similar to that of the starting material. Hydrolysis led to an increase in concentration of not only total free amino acid but also free amino acid such as serine, glutamic acid, alanine, and methionine responsible for umami taste, especially up to about 40 times for methionine. Major free amino acids in amount were leucine, phenylalanine, valine, alanine, and isoleucine and they comprised about half of the total free amino acids, Moisture adsorption, fat adsorption, emulsifying capacity, and foaming capacity of the hydrolysate were 870.1 $\pm$ $7.9\%$, 352.0$\pm$ $5.3\%$, 50.3 $\pm$ $1.2\%$, and $87.5\pm$ $2.5\%$, respectively, and solubility was 83$\~$$84\%$ at acid pH range of 2$\~$4.