• Culinary science and hospitality research
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• v.18 no.2
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• pp.162-171
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• 2012

This study was conducted to investigate the changes of macerating properties from grape suspensions for which both were treated with protopectinase(PPase) and mechanical maceration stored at $4^{\circ}C$ for 28 days. Changes of macerating properties such as pH, total acidity, color, total polyphenol and antioxidant activity of suspensions after enzymatic hydrolysis were determined before and after heating, and microscopic observation made on suspensions containing single cells. With the PPase, grapes were enzymatically macerated to separate cells to primary cell wall without damage. Also, the changes of macerating properties in grape suspension treated with PPase and after heat treatment at $80^{\circ}C$ for 30 min were more stable than those of mechanical maceration, indicating the thermal stability. Thus, the PPase treatment for grapes could be a better choice for preparing highly valuable and functional processed food as well as for prolonging preservation periods.

• The Microorganisms and Industry
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• v.14 no.2
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• pp.26-29
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• 1988

미생물을 이용한 유지의 생산은 동식물 유지의 대체자원으로써의 가능성 때문에 1910년대 독일에서 연구가 시작되어 현재에 이르기까지 계속되어 왔으나 현재까지의 미생물 생산공정으로는 값싼 식물성유지에 비하여 경제성이 떨어지기 때문에 공업적인 생산은 이루어지지 않고 있다. 그럼에도 불구하고 최근들어 미생물유지, 즉 단세포 유지(Singl Cell Oil) 생산에 관한 연구가 늘어나고 있는 것은 몇가지 관점에서 생각해 볼 수 있다. 첫째로는 전세계의 우지생산이 미주, 지중해 연안국및 동남아 몇개국에 국한되어 세계적인 유통이 때로는 원할치가 않아 수급과 가격의 변동이 심하고, 둘째로는 생물공학기술의 발달로 인하여 좀더 경제적인 방법으로 단세포유지를 생산할 수 있는 가능성이 증대되었기 때문이다. 또한 단세포유지는 단세포단백질과는 달리 식용, 사료용이외에 공업용 원료로도 사용될 수 있으므로 소비자들의 선호도, 법적 규제등의 문제가 상대적으로 작은 것도 한 이유가 될 것이다. 본 소고에서는 유지의 종류, 유지생합성및 축적 메카니즘, 단세포유지 발효공학및 유지추출, 단세포유지의 경제성, 단세포유지에 관한 최근의 연구동향에 관하여 살펴보기로 한다.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.64-68
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• 2004

Cell-separating enzyme (Sumyzyme MC) was used to investigate enzymatic maceration of strawberry, sweet persimmon, kiwi, onion, garlic, and cucumber, Maceration rate, volume, brix, color, particle size distribution, and viscosity were determined, and microscopic observation made on suspensions containing single cells. Sweet persimmon and strawberry showed over 90% meceration rates, and kiwi showed 80%. Color, storage test, and sensory evaluations of single-cell suspensions and their filtrates were performed before and after sterilization. Total dietary fiber contents of raw material and single-cell suspension of garlic were 30.77 and 18.55%, respectively, Results indicate fruit and vegetable suspensions produced through enzymatic disintegration using cell-separating enzyme can be utilized as basic materials in the manufacture of single-cell foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.29-34
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• 2003

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change in color, which greatly affects the tastes. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, persimmon was enzymatically macerated to separate cells to primary cell wall without damage. Recovery rates of persimmon treated with PPase and mechanical maceration were 95% and 85%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 50% of vitamin C, which is the most unstable component during the mechanical maceration, remained with an intact form for one day after the enzymatic treatment. When the suspensions of persimmon macerated with both treatments were stored at 4$^{\circ}C$ for 9 days, the mechanically macerated persimmon suspension was decolorized, whereas decolorization, was not found in the enzymatically macerated persimmon suspension. Moreover the mechanically macerated persimmon was greatly deteriorated after heat treatment at 10$0^{\circ}C$ for 60 min, whereas cells of the enzymatically separated persimmon suspension appeared to be stable, indicating increased thermal stability Thus, the PPase treatment of persimmon could be a better choice for preparation of highly valuable and functional processed food as well as for increase in preservation period.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.279-282
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• 1996

The enzyme-linked immunosorbent assay (ELISA)-inhibition test using a Clonorchis sinensis species-specific mouse monoclonal antibody (MAb) , CsHyb 0605-23, showed increased specificity over the conventional ELISA used for serodiagnosis of clonorchiasis. To characterize the corresponding antigen further, the MAb was tested against polysaccharide, protein and glycolipid fractions obtained from a crude extract of C. slnensis adult worms, using chloroform, methanol and phenol extractions. Only the polysaccharide fraction was recognized by the mb among those fractions. Mild oxidation of the antigen with sodium periodate showed decreased reactivity against the MAb. We concluded that the antigen and antigenic determinants recognized by the MAb are carbohydrates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.505-511
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• 2004

The effects of single cells of carrot or radish on the fecal excretion, mineral absorption rate and structure of small intestine and colon were investigated in rats fed 5% single cell diet for 4 weeks. Carrot contained 28.76% of total dietary fiber and 21.45% of insoluble dietary fiber, and radish contained 23.14% of total dietary fiber and 16.77% of insoluble dietary fiber on a dry weight basis. Total dietary fiber contents of the single cell were 44.68% for carrot, 48.0% for radish. Absorption rates of magnesium were higher in the carrot and radish single cell groups than the other groups. Cellulose significantly increased fecal weight and weight of small intestine. The consumption of cellulose and single cells decreased digestibility of lipid. The length of colon were longer in the carrot and the radish group than the other groups. Scanning electron microscopy studies showed that small intestine microvilli with leaf-shaped were seen in cellulose and single cell fed groups. These results suggest that the diet containing 5% single cells of carrot or radish increases the digestibility of dietary fiber, weight gain, and fecal output and shorten the gastrointestinal transit time.

• The Korean Journal of Applied Statistics
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• v.33 no.4
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• pp.511-526
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• 2020

Single-cell RNA-sequencing (scRNA-seq) data consists of each cell's RNA expression extracted from large populations of cells. One main purpose of using scRNA-seq data is to identify inter-cellular heterogeneity. However, scRNA-seq data pose statistical challenges when applying traditional clustering methods because they have many missing values and high level of noise due to technical and sampling issues. In this paper, motivated by analyzing scRNA-seq data, we propose a novel spectral-based clustering method by imposing different weights on genes when computing a similarity between cells. Assigning weights on genes and clustering cells are performed simultaneously in the proposed clustering framework. We solve the proposed non-convex optimization using an iterative algorithm. Both real data application and simulation study suggest that the proposed clustering method better identifies underlying clusters compared with existing clustering methods.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.243.1-243
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• 1979

단세포 단백(SCP)은 토지나 천후조건에 의존하지 않고 대량생산할 수 있는 식량자원이라는 점에서 앞으로 예상되는 지구상의 식량난을 타개할 수 있는 방법으로 주목되고 있다. 단세포 단백을 사료로 이용하는 이외에 식품에 직접 사용하려는 노력이 꾸준히 진행되고 있으며 서구에서는 식용단세포단백의 생산가공이 시작되고 있다. 단세포 단백를 식용으포 직접 이용하기 위하여서는 위생성은 물론 소화성과 기능성은 향상시켜아 하는데 이 목적을 위한 세포벽 파괴의 단백질 추출기술에 관한 연주가 앞서야 한다. 최근 MIT에시는 Yeast의 세포벽 파괴와 단백질 추출 mechanisln을 SEM (Scanning Electron Microscape) 등을 이용한 형태학적 연구로 규명하였다. 식품재료로서의 단세포 단백의 물성과 기능에 대하여 앞으로 연구 할 점이 많으며 이 분야의 연구결과를 검토하여 본다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.401-406
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• 2000

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change of the food quality in color, which greatly affects the tastes of customers. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, Kiwifruit was enzymatically macerated to separate cells to primary cell wall without damage. Yields of kiwifruit treated with PPase and mechanical maceration were 82% and 60%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 95% of vitamin C, which is the most unstable component in application of the mechanical maceration, remained with intact form for one day after the enzymatic treatment. When the suspensions of kiwifruit macerated with both treatments had been stored at $4^{\circ}C for 6 days, the suspension of kiwifruit mechanically macerated was decolorized. whereas decolorization was not found in the enzymatically macerated kiwifruit. Moreover, the mechanically macerated kiwifruit was greatly deteriorated after heat treatment at $100^{\circ}C for 60 min ; the cell suspension of the exzymatically separated kiwifruit appeared to be stable, indicating the thermal stability. Thus, the PPase treatment could be a better choice for preparation of the highly valuable and functional processed food of kiwifruit as well as for prolonging the preservation period of the processed kiwifruit.

• Parasites, Hosts and Diseases
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• v.30 no.1
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• pp.33-42
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• 1992

Naegleria fowleri, a free-living amoeba commonly found in moist soil and fresh water, enters the body via the nasal mucosa and migrates along the olfactory nerve to t he brain, where it causes acute amoebic meningoencephalitis. In the present study 7 clones secreting monoclonal antibodies (McAbs) against N. fowleri were produced and the effector function of them was investigated. Their isotopes were IgGl (Nf 1, Nf 154), 19G3 (Nf 137) and 19A (Nf 1, Nf 2, Nf 256, Nf 279). Five McAbs (McAb Nf 2, Nf 279, Nf 27, Nf 154, Nf 137) were specific for N. fowleri by ELISA and recognized the antigenic determinants located on the trophoBoite surface by IFAT and immunoperoxidase stain. These aye McAbs had capacity to agglutinate N. fowleri trophozoites and inhibited the growth of the amoeba in culture medium. McAb Nf 2 inhibited proliferation of trophozoites in vitro significantly. Also the cytotoxicity of JV. fowleri against CHO cell was reduced in the presence of McAb Nf 2 and McAb Nf 154. From these results McAb Nf 2 was confirmed to weaken the virulence of the amoeba among 7 screened McAbs.