• Korean Journal of Animal Reproduction
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• v.18 no.4
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• pp.235-244
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• 1995

The present study was designed to demonstrate that ES cell lines efficiently could be isolated from explanted blastocysts of hybrid BCF1 mouse when grown on STO feeder layer derived from mouse fibroblasts in culture medium supplemented with leukemia inhibitory factor (LIF). The expanded blastocysts were attached to mitomycin C-inactivated STO feeder layer and were cultured for 4 days. Four days later the ICM was disaggregated by a short term trypsin treatment (0.25% trypsin / 0.04% EDT A for 2-3 min). The resulting cell suspension was seeded on a new STO feeder layer and covered with DMEM supplemented with 10% FCS, 0.1 mM nonessential amino acid, 0.1 mM sodium pyruvate, 0.1 mM mercaptoethanol and 1,000 U/ml LIF. Colonies of ES-like cells were observed after the second passage. These colonies were repeatedly passaged at approximately 5 day intervals. In this study, five ES-like celllines were isolated by directly explanting blastocysts, but three lines were lost after the 5th passage, possibly due to toxic effects of a new FCS batch. The characterization of developmental potential of isolated cell lines was performed with respect to in vitro differentiation and specific activity of alkaline phosphatase (AP). When cells were cultured in suspension, the aggregates of cell lines were capable of forming simple embryoid bodies (EB), and showed the capacity for forming cystic multilayer EBs. In addition, the cell lines were positive for AP staining, a biochemical marker characteristic of mouse ES cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.626-636
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• 2003

Pediococcus pentosaceus K1270 was isolated from naturally fermented kimchi and identified based on the 16S rDNA sequence as well as cultural and biochemical characteristics. This strain strongly inhibited the formation of biofilm by Streptococcus mutans Ingbritt. K1270 also showed antibacterial activity against S. mutans Ingbritt. It was observed that K1270 strain produced hydrogen peroxide on MRS agar supplemented with 3, 3, 5, 5-tetramethylbenzidine (TMB) and peroxidase and the inhibitory effect of K1270 strain on the biofilm formation was reversed by the addition of catalase in part. Culture supernatant of K1270 inhibited the biofilm formation and the multiplication of S. mutans Ingbritt. This inhibitory effect of culture supernatant was decreased slightly by the addition of catalase and abolished by heat or trypsin treatment. Thus, this study suggests that P. pentosaceus K1270 inhibit the biofilm formation through the inhibition of the replication of S. mutans Ingbritt by producing hydrogen peroxide and bacteriocin.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.472-479
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• 2002

The antimicrobial effects of metabolites from isolated strains from feces of Korean newborn baby and from Dongchimi against six food-borne microorganisms, and characteristics of the metabolites were investigated.. The metabolites from isolated strains adjusted pH to 3.5, 4.0, and 4.5 showed strong growth inhibition against S. Typhimurium, and S. Enteritidis. The metabolites has kept its inhibition activities to the pathogens after catalase, trypsin or pepsin treatment. In addition, antimicrobial activity of metabolites was not decreased by heat treatment at $121^{\circ}C$ for 15 min. D2 and F35-2 strains were confirmed homofermentative and F20-3 was heterofermentative bacteria identified by final organic acid and gas production. The amount of lactic acid produced by D2 and F35-2 strains after 24 h of incubation was 1.84 and 1.85% respectively, but F20-3 strain produced acetic acid (0.22%) and lactic acid (0.91%).

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.39-45
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• 2002

It was found that the peptides originated from the hydrolysates of silk fibroin have in vitro immunostimulating effects in murine macrophage RAW264.7 cells. The stimulation effects on nitric oxide (NO) production resulted from treatments of acid or enzymatic hydrolysates were measured. The silk fibroin preparation isolated from cocoon was most efficiently digested by acid hydrolysis. Even though the sole treatment of acid hydrolysate stimulated the NO production in dose-dependent pattern, a part of its activity was found to be caused by the contaminated endotoxin, LPS. When each endotoxin-free hydrolysates obtained by filtering it through an ultrafiltration membrane of molecular weight (MW) cut-off 10,000 to eliminate LPS was used, the peptic hydrolysate with lowest degree of hydrolysis showed the highest activity. The fractions of peptic hydrolysate with MW ranges of 1,000∼10,000, 500∼1,000 and below 500 also showed a higher MW-higher activity correlation. From the analyses of amino acid composition of each hydrolysate, it was found that the contents of arginine, lysine, alanine and glycine residues affected the activity level of hydrolysate. The results of this study showed a possibility of utilizing fibroin as a source for immunostimulating (chemopreventive) functional peptides.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.229-235
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• 1992

Fish protein hydrolysates(FPH) prepared from defatted mackerel meal by proteases such as complex enzymes, bromelain, alcalase, $\alpha-chymotrypsin,$ trypsin, papain and pepsin were tested for inhibitory activity against angiotensin-I converting enzyme(ACE). Among proteases tested, the hydrolysates obtained from the treatment of complex enzymes or bromelain showed relatively higher activity. ACE inhibitory activity of the hydrolysates increased until hydrolysis of 8 hrs, and was stable by heat treatment for 20min at $100^{\circ}C.$ From the profiles of fractionation of the hydrolysates with Bio-gel P-2, the most active fraction had about MW 1,450 and it's amino acid was abundant in Asp, Glu, Lys, Leu, Val and Ala. $IC_{50}\;(amounts\;of\;inhibitors\;needed\;for\;50\%\;inhibition)$ of the active fraction of the hydrolysates obtained from the treatment of complex enzyme and bromelain was 90 and $130 {\mu}g,$ respectively.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.223-232
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• 1984

The influences of some factors involved in removing glucose from egg white by the glucose oxidase system be fore drying were investigated. And the properties between foams prepared from raw and enzyme-treat ed egg white was compared. The results obtained we re summarized as follows; 1. The dianisidine method was found to be suitable for the measurement of egg white glucose in the range up to 100ug/ml. 2. The optimal pH of glucose oxidase activity on glucose was found to be a bout 5.0, and thats activity was most stable in the pH range of about 4.0~5.0 when that enzyme was treat ed for 30 minute at $50^{\circ}C$. 3. The optimal temperature for glucose oxidase reaction on glucose was found to be about $20^{\circ}C$, and that enzyme activity was s table up to $50^{\circ}C$. 4. The removing rate of glucose from egg white with glucose oxidase was influenced by the enzyme concentration, pH and oxygen addition, and the react ion time of the desugarization was about 10 hour sunder the conditions of 0.5% hydrogen peroxide, pH 7.0 and $26^{\circ}C$. 5. All of the each egg white treated with glucose oxidase, glucose oxidase+pancreatin, glucose oxidase+trypsin showed highly foaming ability than that of natural egg white(control), but thats foam stability, on the contrary, was reversed.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.117-125
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• 2019

The aim of the study was to investigate the effects of dietary supplementation of zinc (Zn) sources (zinc oxide and Zn-methionine) on performance, organ weights, blood biochemical profiles, and digestive enzymes of the pancreas and small intestine in Korean native chicks (KNC). A total of 144 KNC (n=6) were fed a basal diet (CON, 100 ppm of Zn), a basal diet supplemented with 50 ppm of Zn with ZnO (ZNO), or a basal diet supplemented with 50 ppm of Zn with Zn-methionine (ZMT) for 28 days. There was no significant difference in body weight, gain, feed intake, and feed conversion ratio among the three groups. The relative weights of the liver, spleen, and intestinal mucosa were unaffected by the dietary source of Zn, whereas pancreas weight in the ZNO group decreased (P<0.05) compared with that in the CON and ZMT groups. Blood biochemical components including aspartate aminotransferase, and alanine aminotransferase were unaffected by dietary Zn supplementation. Pancreatic trypsin activity in the ZNO and ZMT groups was significantly (P<0.05) enhanced compared with that in the CON group. However, the activities of ${\alpha}$-amylase and carboxypeptidase A were not altered by dietary Zn supplementation. The activities of maltase and sucrase were unchanged, whereas the activity of leucine aminopeptidase tended (P=0.08) to be increased by dietary Zn supplementation. In conclusion, the supplementation with 50 ppm of ZnO or Zn-methionine resulted in an activation of protein digestive enzymes in the pancreas and small intestine without affecting animal performance in KNC.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.9-18
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• 2016

Two Bacillus strains, CJW15 and SSD8, with strong antibacterial activities were isolated from cheonggukjang. Both were identified as B. amyloliquefaciens strains after gene sequencing of rRNA and recA. CJW15 strongly inhibited the growth of B. cereus (ATCC14579), Listeria monocytogenes (ATCC19111), and Lactococcus lactis (ATCC11454). In comparison, SSD8 inhibited the growth of B. cereus (ATCC14579) and Enterococcus faecium (ATCC19953). The antibacterial activities of the two strains were not affected when exposed to a temperature of $100^{\circ}C$ for 15 min and were quite stable in acidic (pH 3) and alkaline (pH 12) pH conditions. Enzymatic treatments (trypsin, pepsin, proteinase K, and protease) had no effect on the activity of CJW15, but reduced the activity of SSD8 by half. Both isolates possess genes involved in the synthesis of lipopeptides (e.g. surfactin, fengycin, iturin, and iturin A), and genes encoding subtilin, a bacteriocin. Moreover, both isolates have fibrinolytic activities as well.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.426-433
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• 2009

Fish scales have potential in functional food preparation due to their antioxidant and antihypertensive properties. We investigated the angiotensin I converting enzyme (ACE) inhibitory activity of Tilapia mossambica scale extracts. Hydrolysates of tilapia scales were prepared by enzymatic extraction using five proteases (${\alpha}$-chymotrypsin, Alcalase, Kojizyme, Protamex and trypsin) after scales were treated with hot water for 3 hr. Scale enzymatic hydrolysates prepared using both hot water and enzyme treatments exhibited elevated hydrolysis (about 25%-55%) compared to only enzyme treatment (about 15%-45%). Enzymatic hydrolysates (1 mg/mL) prepared by both hot water and enzyme treatments also showed significantly increased ACE inhibitory activities from about 20%-75%. The pattern of ACE inhibitory activities was similar to the degree of hydrolysis. Alcalase and ${\alpha}$-chymotrypsin hydrolysates displayed the highest ACE inhibitory activities ($IC_{50}$ = 0.83 mg/mL and 0.68 mg/mL, respectively). In addition, the ACE inhibitory effects of $IC_{50}$-chymotrypsin hydrolysates increased with decreasing molecular weight (5 kDa>, 10 kDa> and 30 kDa>), with the 5 kDa> fraction displaying the highest ACE inhibitory activity (about 89.9% and $IC_{50}$ = 0.1 mg/mL). We suggest that the peptide compounds of enzymatic hydrolysates prepared from tilapia scale enhances ACE inhibitory activity and might be useful as an antihypertensive material.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.875-881
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• 1998

To develop functional food material with angiotensin converting enzyme (ACE) inhibitory peptides, muscle protein of anchovy, Engraulis japonica was hydrolyzed during 48 hrs by digestive pretenses such as pepsin, trypsin, $\alpha$-chymotrypsin, and commercial proteases such as papain, bromelain, complex enzyme, Elavourzyme, Novozym, Neutrase, Protamex and Alcalase. The only $50\%$ ethanol soluble hydrolysates were tested for inhibitory activity against ACE and yield of $50\%$ ethanol soluble peptide-nitrogen ($ESPN_{50}$). ACE inhibition effects and yield of $ESPN_{50}$ occurred as hydrolysis time increased to 8 hrs, Among those pretenses tested, hydrolysates by Alcalase and $\alpha$-chymohypsin had greater ACE inhibitory activity (80 and $74\%$, reipectively) with eletated levels of $ESPN_{50}$ (48 and 58 mg/ml, respectively), while Protamex hydrolysates had greater ACE inhibitory activities ($73\%$) with reduced levels of $ESPN_{50}$ (7.2mg/ml) than others. Amino acid compositions of $50\%$ ethanol solubles obtained from those hydrolysates were rich in glutamic acid, aspartic acid, cysteine and leucine.