• 생명과학회지
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• 제28권11호
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• pp.1277-1284
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• 2018

본 연구에서는 효모염색체내에 다양한 유전자 발현 cassette를 도입하기 위해 Cre/loxP system을 가진 repeated yeast integrative plasmid (R-YIp)를 구축하였다. R-YIp는 반복적으로 형질전환체를 선별할 수 있는 selective marker (CgTRP1)와 loxP 서열, 그리고 integration을 위한 목적서열을 함유하고 있어 같은 염색체의 동일한 위치에 여러 개의 유전자 발현 cassette를 도입하는 것이 가능하다. 따라서 xylan/xylose 대사에 관련된 endoxylanase (XYLP), ${\beta}$-xylosidase (XYLB), xylose reductase (GRE3) 그리고xylitol dehydrogenase (XYL2)의 효모염색체내에 도입을 시도하였다. 먼저 XYLP, XYLB, GRE3그리고 XYL2 유전자의 효율적인 발현을 위한 promoter를 선별하기 위해 pGMF-GENE과 pAMF-GENE plasmid를 구축하였고, 각 유전자들의 발현에 GAL10 promoter가 적합함을 확인하였다. 다음으로 GAL10p-GENE-GAL7t cassette를 가진 pRS-GENE plasmid (R-YIp)를 구축하여, 반복적 integration 과정과 selective marker의 제거를 통해 각각의 R-YIps를 효모 7번염색체에 순차적으로 도입하였다. R-YIp system을 통해 효모염색체내에 도입된 유전자들은 모두 안정적으로 발현되었고, 활성형의 재조합효소를 생산함을 확인할 수 있었다. 따라서 다수의 외래유전자를 효모염색체내 도입함에 있어 selective marker와 숙주세포 선택의 한계를 R-YIp system을 통해 어느 정도 극복할 수 있을 것이라 기대한다.

• 문화기술의 융합
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• 제8권6호
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• pp.921-926
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• 2022

Astree사의 E-Tongue을 이용한 상대적 단맛 평가를 위하여 검토한 7개의 센서 중 PKS 및 NMS 센서가 1차로 선정되었다. PKS 및 NMS 센서를 이용해 설탕을 비롯한, 과당, 포도당 및 자일리톨, 5%, 10% 및 15% 용액을 분석한 결과, 자일리톨 및 과당의 농도 증가에 따른 PKS 센서 감응도의 변화가 미미하여, 최종적으로 NMS 센서를 단맛 측정 센서로 선정하였다. 이들 감미료의 농도 중 5% 용액을 모든 센서를 활용한 PCA(주성분 분석) 통계 방법으로 처리한 결과에서는 DI (식별지수)값이 -0.1로 감미료 상호 간 구분이 힘들었으나, NMS 센서만을 이용한 상대적 센서 감응도는 농도에 관계없이 일정한 수치를 나타내었다. 과당 및 자일리톨의 상대적 센서 감응도는 각각 1.08 및 1.00으로 사람의 미각으로 측정한 문헌상 관능검사의 상대적 감미도 범위에 포함되었으나, 포도당의 경우는 0.99로 문헌상 상대감미도 0.5~0.75보다 높게 나타났다. 5%~15% 농도 범위에서 설탕 대비 3종 감미료에 대한 NMS 단일센서를 이용한 E-Tongue의 우수한 정밀성 (%RSD, 1.53~3.64%)을 고려할 때 향후 가당 음료 등에 대한 신제품 개발 및 품질관리 등에 관능검사를 대체할 수 있는 가능성을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제7권5호
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• pp.310-317
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• 1997

Enzymatic synthesis of glucosyl-sugar alcohols using various transglycosylating enzymes, such as cyclodextrin glucanotransferase (CGTase), ${\alpha}$-amylase, ${\alpha}$-glucosidase, and pullulanase was investigated using various sugar alcohols, such as sorbitol, xylitol, inositol, maltitol, and lactitol as glucosyl acceptors. CGTase showed the highest transglycosylating activity to sugar alcohols compared to other transglycosylating enzymes, and inositol and maltitol were the most suitable glucosyl acceptors. Soluble starch, extruded starch, cyclodextrins, and maltooligosaccharides were also identified to be adequate glucosyl donors for transglycosylation reaction of CGTase to sugar alcohols. The synthesis of glucosyl-maltitol in the reaction system using extruded starch as the glucosyl donor and maltitol as the glucosyl acceptor showed the best results showing the highest transglycosylation yield. The transglycosylation products were purified by activated carbon column chromatography with ethanol gradient elution. Chemical structures of above transglucosylated products were analyzed by nuclear magnetic resonance spectroscopy, and two products were identified to be maltotritol and maltotetraitol, in which one or two glucose molecules attached to the parent maltitol molecule by a ${\alpha}$-l,4-glucosidic bond, respectively.

• 미생물학회지
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• 제31권2호
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• pp.99-104
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• 1993

Two strains of the gram-negative acetic acid bacteria, Acetobacter sp. strain CS2- AND CS5, were isolated form the traditional raw rice wine vinegar of Haenam area. The strains oxidized ethanol to acetic acid and over-oxidized acetate and lactate to $CO^{2}$ and $H ^{2}$O. They produced 2-ketogluconic acid from glucose but did not produce .gamma.-pyrones from glucose and dihydroxyacetone from glycerol. The CS strains possessed ubiquinone-9 as a major isoprenoid quinone and contained straight-chain $C_{18 :1}$, $_C{16 : 0}$, and $C _{14 : 0}$ fatty acids. The DNA base composition of the CS2 and CS5 strains was 56.2 and 57.3 mole% G + C, respectively. The isolates were grown well on methanol, gluconate, erythritol, raffinose, dulcitol and xylitol as sole sources of carbon and energy which are different from those of other Acetobacter species and producedd acid from sucrose, glycerol, fructose, inositol, mannitol, and ribose.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• Asian-Australasian Journal of Animal Sciences
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• 제21권6호
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• pp.896-902
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• 2008

The objective of this research was to create a new probiotic candy with good flavor and healthy benefits by using the response surface method and a sequential quadratic programming technique. The endpoint was to increase the varieties of dairy products and enhance their market values. In this study, milk was mixed with yogurt cultures (Lactobacillus bulgaricus, Streptococcus thermophilus) and probiotics (L. paracasei, Bifidobacterium longum) and incubated at $37^{\circ}C$ for 20 h. The samples were blended with lyoprotectants (galactose, skim milk powder and sucrose), freeze dried and then mixed with sweeteners (lactose and xylitol) to improve the texture for forming tablets. The processing conditions were optimized in two steps: the first step constructed a surface model using response surface methodology; the second step optimized the model with a sequential quadratic programming procedure. Results indicated that skim milk inoculated with L. delbrueckii subsp. Bulgaricus, S. thermophilus, L. paracasei subsp. paracasei and B. longum and blended with 6.9% of galactose, 7.0% of sucrose and 8.0% of skim milk powder would produce a new probiotic candy with the highest viability of probiotics and good flavor. A relatively higher survival of probiotics can be achieved by placing the probiotic candy product in a glass bottle with deoxidant and desiccant at $4^{\circ}C$. These probiotic counts remained at 106-108 CFU/g after being stored for two months.

• 한국치위생학회지
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• 제14권1호
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• pp.17-24
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• 2014

Objectives : The purpose of this study was to investigate cognition on oral health education and dental caries preventive effect in kindergartens and child care facilities. Methods : A self-reported questionnaire was completed by 260 teachers in kindergartens and nursery facility in Daejeon from January to February, 2013. Except incomplete answers, 248 questionnaires were analyzed by using the statistical package SPSS WIN 18.0. Results : High intention to participate in oral health education was shown in the teachers who experienced the oral health education. Dental caries preventive effect included correct tooth brushing, fluoride dentifrice, fluoride mouth rinse, and use of xylitol. The teachers agreed that the fluoride mouth rinses would help good oral health in the children. Conclusions : Teachers in kindergartens and nursery facility are the most important persons in childhood oral health care. So it is necessary to provide the continuing standardized education for the teachers systematically.

• 한국동물위생학회지
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• 제23권2호
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• pp.137-142
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• 2000

In order to develop a good separation and simultaneous analysis of different sugar in an artificial mixed sugar solution, we analyzed 10 sugar components in an artificial mixed sugar solution composed of fructose, glucose, mannitol, sucrose, maltose, lactose, xylose, xylitol erythritol, and trehalose with using HPLC-ELSD or HPLC-RI. Separation and quantification by HPLC-ELSD was superior to those by HPLC-RI and detection sensitivity by HPLC-ELSD was higher then that by HPLC-RI as micorgram($\mu\textrm{g}$) level. 1. The units of minimal detectable limits were showed $\mu\textrm{g}$/$m\ell$ and ng/$m\ell$ by the HPLC-RI and HPLC-ELSD, respectively. 2. The condition of ELSD was drift tube temperature $82^{\circ}C$, $N_2$ gas flow rate 2.10 SLPM, and colum oven temperature $30^{\circ}C$, respectively. Isolation and recovery rates of single sugar from the multiple sugar solution was higher at the condition (time: flow rate: D.W.:ACN MeOH, min : $m\ell$/min:v:v:v) of linear gradient elution of mobile phase as 0 : 1.00 : 15 : 85 : 0.1 : 1.00 : 6 : 90 : 4, 17 : 1.00 : 10 : 70 : 20, 28 : 1.00 : 15 : 85 : 0 an 35 : 1.00 : 15 : 85 : 0, in order.

• 한국축산식품학회지
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• 제42권5호
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• pp.849-860
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• 2022

The myofibril protein (MP) isolate-saccharide graft reactions was prepared using the Maillard reaction with saccharides. The effects of various saccharides on protein functionality and quality of the Maillard reaction were investigated and compared with those of MP. The grafting degree of the MP isolate-saccharide graft reaction was significantly higher in the reducing sugar-treated groups (lactose, glucose, fructose, and palatinose). The browning intensity of the MP isolate-saccharide graft reaction with fructose, sucrose, and erythitol was higher than that observed in the control reaction (p<0.05). MP that reacted with reducing sugars (glucose, fructose, palatinose, and lactose) had fainter bands than MP that reacted with non-reducing sugars (sucrose, erythitol, trehalose, sorbitol, and xylitol). MPs conjugated with glucose exhibited higher protein solubility. The palatinose and lactose treatments were maximum in water binding capacity, though no significant difference in oil binding capacity among the saccharide treatments was observed. The emulsion stability of the MP isolate-saccharide graft reaction with palatinose and erythitol was higher than that of the control reaction. Therefore, reducing sugars have good protein functionality in the MP isolate-saccharides graft reaction.

• 한국학교보건학회지
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• 제17권2호
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• pp.11-22
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• 2004

Purpose: The aim of this study was to evaluate the effects of oral health care programs in 3 school-based oral health care center among primary schoolchildren. Methods: School-based oral health care programs included fluoride mouth rinsing, pit and fissure sealing for permanent premolars and molars, fluoride gel application and chewing of xylitol candy. All of the programs were carried out by one dental hygienist among 'D' primary schoolchildren in Daegu city under the supervision of a dentist. Baseline dental examinations were completed and preventive care was implemented for 544 children during one year. All of the children visited a school-based oral health care center every three months for a regular check-up. The final oral examination was conducted from March 15 to April 1, 2004. The data analysis data was made on the basis of SAS 8.01. Mean differences between 2003 and 2004 data were compared by paired t-test. Corresponding p-values were considered significant at values less than 0.05. Results: The DMF rate and DFT index were reduced to 8.0% and 8.4% during one year respectively, but there were no statistically significant differences. The DMF rate was significantly reduced (16.3%) after a one year program of school-based oral health care practice. The DMFT(Decay Missing Filling Tooth) index was also reduced compared to 2003 throughout the entire grade. Conclusion: School-based oral health care programs can reduce the prevalence of dental caries prevalence among schoolchildren during one year. This program also improved the oral health capacity of schoolchildren. It is recommend that the school-based oral health care program should be extended to every primary school in Korea.