• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.73-80
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• 2010

Two nitrite oxidizing bacteria, NOB1 and NOB2, were isolated from anaerobic digester liquer of food wastewater and analyzed for their growth characteristics and the ability to oxidize nitrite under different temperature, pH, and DO( dissolved oxygen) concentrations. Both of the isolated strains have shown the best growth at pH 7.0 and at $35^{\circ}C$, and also shown higher growth rate with the increasing dissolved oxygen concentrations. As the factors to restrict the growth of these strains, parameters such as pH and DO were found to be effective ones, by increasing (up to 9.0) or decreasing pH (up to 5.0), or lowing DO below 1.0 ppm. Especially, the ability to oxidize nitrite in both strains was about 50% lower in below 1.0 ppm of DO than above of 1.0 ppm. NOB2 was found to be two times greater in both the growth rate and the nitrite-oxidizing ability than NOB1.

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.73-82
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• 2008

In this study, a dry single-phase anaerobic digestion process (Dranco system) was investigated to evaluate the optimum operational conditions. Several factors such as injection rate of organic waste, biogas production, $CH_4$ content in the biogas, pH of the sludge, $NH_3$-N and VFA concentration were investigated based on the operation of the digestion process for 2 months (short term) and 8 months (long-term). The operation results showed that a small quantity of food waste should be injected every week and that a 10% increase of the microorganism injection rate should be needed. However, normal operation was conducted after 11 weeks based on the designed quantity. The $CH_4$ content in the biogas was high at the beginning and the end of the food injection. However, it was low during week days. When the biogas production was high, the $CH_4$ concentration was low. The biogas production increased with an increase of the injection rate. $100m^3$/ton of biogas was produced from normal operation of the digestion process based on the designed quantity. The pH values of the digestion tank based on short-term operation ranged from 8 to 8.5. However, the pH values ranged from 7.45 to 8.15 after 4 weeks of long-term operation. The $NH_3$-N concentration of short-term operation ranged from 4,500 to 5,500 ppm and it gradually decreased to 2,000ppm after normal operation was commenced. For long-term operation, it was 5,000ppm initially and 3,800ppm after normal operation was commenced. The VFA concentration of sludge was less than 900ppm and 2,500ppm for short and long-term operations, respectively, after normal operation. Overall, the differences between sludge pH, $NH_3$-N and VFA concentrations may be due to the different types of microorganisms and the digestion ability of the microorganisms which exist in the accumulation of non digested organics. Moreover, it may be also caused by the type of food waste. Further investigation is needed to confirm these relationships.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1993-2005
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• 2019

Thermophilic anaerobic digestion (TAD) is characterized by higher biogas production rates as a result of assumedly faster microbial metabolic conversion rates compared to mesophilic AD. It was hypothesized that the thermophilic microbiome with its lower diversity than the mesophilic one is more susceptible to disturbances introduced by alterations in the operating factors, as an example, the supply of nitrogen-rich feedstock such as poultry manure (PM). Laboratory scaled TAD experiments using cattle slurry and increasing amounts of PM were carried out to investigate the (in-) stability of the process performance caused by the accumulation of ammonium and ammonia with special emphasis on the microbial community structure and its dynamic variation. The results revealed that the moderate PM addition, i.e., 25% (vol/vol based on volatile substances) PM, resulted in a reorganization of the microbial community structure which was still working sufficiently. With 50% PM application, the microbial community was further stepwise re-organized and was able to compensate for the high cytotoxic ammonia contents only for a short time resulting in consequent process disturbance and final process failure. This study demonstrated the ability of the acclimated thermophilic microbial community to tolerate a certain amount of nitrogen-rich substrate.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.95-99
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• 1995

Acid phosphatase(AP) of he aphid, Megoura crassicauda and the major component of the lady beetle's artificial diet, fresh chicken liver, was adapted as a model protein to study the digestion of diet proteins in the midgut of Harmonia axyridis. The lady beetle did not secrete its own AP into the lumen of the midgut. The aphid and the live chicken liver had AP which was still alive in enzymatic activity from the extract of the lumen of the midgut of the lady beetle. The digestive ability of the lady beetle on proteins turned out to be different depending on food sources. In the lumen of the midgut of the lady beetle, though most of AP of live chicken liver lost its activity withtin 12 hours, that of M. cassicauda kept strong enzymatic activity up to 24 hours.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.216-223
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• 2010

Abalone (Haliotis discus hannai), mostly distributed and maricultured in southwestern coastal areas of South Korea, is recognized as an economically important species in the fishery industry. Abalone intestines are one of the by-products of abalone processing. To investigate abalone intestines as bioactive substances, abalone intestine gastrointestinal digests (AIGIDs) of various molecular weights (MWs) were prepared using in vitro gastrointestinal digestion and an ultrafiltration system, and tested for inhibitory effects against reactive oxygen species (ROS) and oxidative stress in macrophage cells treated with hydrogen peroxide ($H_2O_2$). In our results, among AIGIDs, AIGID-III (MW=5-10 kDa) showed potent inhibitory activities for lipid peroxidation and free radicals. Additionally, the results clearly indicated that AIGID-III treatment could prevent cytotoxic damage of macrophages by $H_2O_2$-induced oxidative stress due to its potent scavenging ability against cellular ROS. These results suggest that AIGIDs may have protective and therapeutic potential for oxidative stress syndromes and immune diseases through ROS inhibition in macrophage cells.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1110-1117
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• 2001

Responses of the rumen fungus, Neocallimastix frontalis RE1, to long chain fatty acid (LCFA) were evaluated by measuring gas production, filter paper (FP) cellulose digestion and polysaccharidase enzyme activities. LCFA (stearic acid, $C_{18:0}$; oleic acid, $C_{18:1}$; linoleic acid, $C_{18:2}$ and linolenic acid, $C_{18:3}$) were emulsitied by ultrasonication under anaerobic condition, and added to the medium. When N frontalis RE1 was grown in culture with stearic, oleic and linoleic acid, the cumulative gas production, gas pool size, FP cellulose digestion and enzymes activities significantly (p<0.05) increased at some incubation times(especially, exponential phases of fungal growth, 48~120 h of incubation) relative to that for control cultures. However, the addition of linolenic acid strongly inhibited all of the investigated parameters up to 120 h incubation, but not after 168 and 216 h of incubation. These results indicated that stearic, oleic and linoleic acids tended to have great stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (p<0.05) inhibitory effects on the cellulolysis by the rumen fungus. These results are the first report of the effect of LCFAs on the ruminal fungi. Further research is needed to identify the mode of action of LCFAs on fungal strains and to verify whether or not ruminal fungi have ability to hydrate unsaturated LCFAs to saturated FAs. There was high correlation between cumulative in vitro gas production and fungal growth (94.78%), FP cellulose degradation (96.34%), CMCase activity(90.86%) or xylanase activity (87.67%). Thus measuring of cumulative gas production could be a useful tool for evaluating fungal growth and/or enzyme production by ruminal fungi.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.12
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• pp.1897-1906
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• 2019

Objective: An experiment was conducted to investigate the effects of dietary non-phytate phosphorus (nPP) deficiency on intestinal pH value, digestive enzyme activity, morphology, nutrient utilization, and gene expression of NaPi-IIb in meat ducks from 1 to 21 d of age. Methods: A total of 525 one-d-old Cherry Valley ducklings were fed diets (with 7 pens of 15 ducklings, or 105 total ducklings, on each diet) with five levels of nPP (0.22%, 0.34%, 0.40%, 0.46%, or 0.58%) for 21 d in a completely randomized design. Five experimental diets contained a constant calcium (Ca) content of approximately 0.9%. Body weight (BW), body weight gain (BWG), feed intake (FI), and feed to gain ratio (F:G) were measured at 14 and 21 d of age. Ducks were sampled for duodenum and jejunum digestion and absorption function on 14 and 21 d. Nutrient utilization was assessed using 25- to 27-d-old ducks. Results: The results showed ducks fed 0.22% nPP had lower (p<0.05) growth performance and nutrient utilization and higher (p<0.05) serum Ca content and alkaline phosphatase (ALP) activity. When dietary nPP levels were increased, BW (d 14 and 21), BWG and FI (all intervals), and the serum phosphorus (P) content linearly and quadratically increased (p<0.05); and the jejunal pH value (d 14), duodenal muscle layer thickness (d 14), excreta dry matter, crude protein, energy, Ca and total P utilization linearly increased (p<0.05); however, the serum ALP activity, jejunal $Na^+-K^+$-ATPase activity, and duodenal NaPi-IIb mRNA level (d 21) linearly decreased (p<0.05). Conclusion: The results indicated that ducks aged from 1 to 21 d fed diets with 0.22% nPP had poor growth performance related to poor intestinal digestion and absorption ability; but when fed diets with 0.40%, 0.46%, and 0.58% nPP, ducks presented a better growth performance, intestinal digestion and absorption function.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.3001-3003
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• 2013

Objective: Spleen tyrosine kinase (Syk) is closely related to tumor invasion and metastasis, and has been shown to have potential inhibitory effects in tumors. In this study, we constructed a eukaryotic expression vector for Syk and analyzed its effects on invasive ability of the A549 non-small cell lung cancer cell line in vitro. Methods: A fragment of Syk was obtained by RT-PCR from human lung cancer cells and cloned into the expression vector pLNCXSyk. After restriction endonuclease digestion, PCR and DNA sequencing confirmation, the recombinant Syk expression plasmid was transfected into A549 human lung cancer cells using lipofectamine protocols. After selection, the cells stably expressed Syk. Detection of Syk expression of the cells by RT-PCR, and invasive ability were examined. Results: The eukaryotic expression plamid pLNCXSyk was constructed and expressed stably in the A549 human lung cancer cells. The RT-PCR results showed that Syk mRNA expression was upregulated significantly (P<0.05). Lower invasion through a basal membrane were apparent after transfection (P<0.05). Conclusions: A eukaryotic expression plasmid to cause Syk expression in lung cancer cells can obviously inhibit their invasive ability in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.713-717
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• 1998

The synergistic effect of fetal calf serum (FCS) and chicken embryo extract (CEE) on protein synthesis of chicken embryo myoblasts was examined. Myoblasts were derived from chicken embryo cultured for 14 days by trypsin digestion and cultured in 5% $CO^2/95%$ air at $37^{\circ}C$. When myoblasts were cultured at the low level of cell density (20-50% of well), CEE enhanced the ability of FCS to stimulate protein synthesis of myoblasts. However, there was no significant effect of CEE to stimulate protein synthesis of myoblasts cultured at high level of cell density (100% of well).

• Food Science and Industry
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• v.52 no.1
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• pp.60-67
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• 2019

Protein is a major nutrient of food and has long been studied for nutritional and utility value. Among them, rice protein is attracting attention because of its hypoallergenic characteristics and nutritional value. Rice proteins are divided into endosperm protein and bran protein depending on their location. The two proteins differ in their nutritional characteristics and applications. The endosperm protein is an insoluble protein and has an advantage of digestion and absorption. Rice bran protein dissolves well in water. Its amino acid value is high enough to be comparable to that of soy protein, and it has strong antioxidant ability. Rice protein is a healthy vegetable protein because of its health and hypoallergenic properties. It has been widely used in children's or patients' food, and recently for muscle supplement and health food. Rice protein is considered to be a very effective and useful material as it has been discovered so far.