• Preventive Nutrition and Food Science
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• v.6 no.4
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• pp.206-210
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• 2001

Starch is an abundant resource in plant biomass, and it should be hydrolyzed enzymatically into fermentable sugars for ethanol fermentation. A genetic recombinant yeast, Saccharomyces cerevisiae GA-7458, was constructed by integrating the structural gene of both $\alpha$-amylase from Bacillus stearothermophilus and the gene (STA1) encoding glucoamylase from S. diastaticus into the chromosome of S. cerevisiae SH7458. The recombinant yeast showed active enzymatic activities of $\alpha$-amylase and glucoamylase. The productivity of ethanol fermentation from the pH-controlled batch culture (pH 5.5) was 2.6 times greater than that of the pH-uncontrolled batch culture. Moreover, in a fed-batch culture, more ethanol was produced (13.2 g/L), and the production yield was 0.38 with 2% of corn starch. Importantly, the integrated plasmids were fully maintained during ethanol fermentation.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.21-25
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• 2005

As a means for year-round rearing of bumblebee, CO$_{2}$ -narcosis time favorable for colony development was identified in Bombus terrestris. CO$_{2}$ -narcosis time divided into five classes: 11 days of adult emergence (A-11), the day of adult emergence (A-0), late pupal stage (LP), middle pupal sta ge (MP), and early pupal stage (EP). In egg-laying characteristics, the oviposition rate of LP, A-11 and A-0 was over 76.0$\%$, but that of MP and EP was less than 61.1 $\%$. At the same time, the days needed to first oviposition shortened to 9.8 ­10.5 days in A-11, A-O and LP, comparing to 13.7 -16.1 days in MP and EP. The rate of colony foundation, progeny-queen produced and period of colony foundation of A-11 were the best results in among those at different CO$_{2}$-treatment time. The number of worker produced was 109.2 -110.5 in A-H, LP and A-H, comparing to 82.0 - 86.8 in MP and EP. Also, the number of progeny-queen produced of A-H, A-O and LP was 36.1, 41.0 and 71.3, respectively, which corresponded to 1.5 - 3.1 fold higher than MP and EP. Taken these together, CO$_{2}$-narcosis time favorable for colony development was determined to be 11 days of adult emergence. Also, the day of adult emergence and late pupal stage showed a positive effect on the oviposition and colony development in CO$_{2}$-narcosis time.

• Korean Journal of Medicinal Crop Science
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• v.1 no.2
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• pp.166-170
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• 1993

In order to determine the optimum planting density of Job's Tear, We investigatedagronomic characters, yield components and yields by using Ewon and Heuksuk cultivar. The characters, plant height, stem diameter, number of stems per $m^2$ and number of leaves per $m^2$, etc., were excellent in $60{\times}15cm$ planting space for the Ewon and Heuksuk local cultivar. Both the weight of 100 grains and that of 1 liter also higher for the Ewon local cultivar, and yield of stem and seed were the most excellent in $60{\times}15cm$ planting space for the Ewon and Heuksuk local cultivar. For the Ewon and Heuksuk, the analysis of variance for agronomic characters following the difference of planting density were acknowledged to be worth of attention.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.87-93
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• 1982

Dihaploid lines derived from the another of the $F_1$ of single cross, SC72 $\times$ Hicks (Nicotiana tabacum L.) were estimated the variation, heritablities, genetic correlations and path-co-efficients on agronomic characters and chemical compositions. Dinaploids exhibited reduced vigor and growth when comparecd with the mid-parent value but had increased nicotine contents, and the range of dihaploids characters were deviated more than that of their parents. Heritabilities of days to flowering, leaves per plant, nicotine. contents, leaf size and plant height appeared high value, and the yield, value per kg. and reducing sugar contents were low. There were positive genetic correlations between yield, and value per kg., leaf width, leaves per plant and reducing sugar contents and negative genetic correlations appeared between nicotine contents and the other characters except for index of leaf shape. Path-coefficient analysis of genotypic correlation coefficients showed that leaves per plant and leaf width lave a high direct effect, and plant height and days to flowering have a high indirect effect on yield, respectively.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.271-278
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• 2020

Enterotoxigenic Escherichia coli is one of the major causative infectious agents of diarrhea in newborn and post-weaning pigs and leads to a large economic loss worldwide. However, there is limited information on the distribution and characterization of virulence genes in E. coli isolated from diarrheic piglets, which also applies to the current status of pig farms in Korea. To investigate the prevalence and characterization of virulence genes in E. coli related to diarrhea in piglets, the rectal swab samples of diarrheic piglets (aged 2 d to 6 w) were collected from 163 farms between 2013 and 2016. Five to 10 individual swab samples from the same farm were pooled and cultured on MacConkey agar plates, and E. coli were identified using the API 32E system. Three sets of multiplex PCRs were used to detect 13 E. coli virulence genes. As a result, a total of 172 E. coli isolates encoding one or more of the virulence genes were identified. Among them, the prevalence of individual virulence gene was as follows, (1) fimbrial adhesins (43.0%): F4 (16.9%), F5 (4.1%), F6 (1.7%), F18 (21.5%), and F41 (3.5%); (2) toxins (90.1%): LT (19.2%), STa (20.9%), STb (25.6%), Stx2e (15.1%), EAST1 (48.3%); and (3) non-fimbrial adhesin (19.6%): EAE (14.0%), AIDA-1 (11.6%) and PAA (8.7%), respectively. Taken together, various pathotypes and virotypes of E. coli were identified in diarrheic piglets. These results suggest a broad array of virulence genes is associated with coliform diarrhea in piglets in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.1-10
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• 2002

Biomass distribution of zooplankton showed its lowest level in June in the Cheju Strait, and the highest one was noticed in November when the secondary productivity is considered high. The highest biomass of zooplankton appeared in the sea areas of Sta. 14 and 11 respectively with relation to oceanographic conditions and wet weight of biomass. The positions were the center part of the Cheju Strait, while the sea area of the South Sea of Korea and the northern coast of Cheju Island showed relatively low biomass distribution. The characteristic of the sea area where biomass was densely distributed was it was in patch shape. Meanwhile, biomass distribution was higher in the northern sea area of Cheju Island than In the coastal sea of the South Sea of Korea. It shows formation of hairtail fishing grounds is closely related to biomass distribution in the Cheju Strait. In addition, high biomass is displayed in the center part of the saddle shaped ocean, a boundary of the heterogeneous water mass as a feature of fall oceanographic condition. Good fishing grounds of a hairtail In the Cheju Strait were formed outside of the sea area that showed patch-shaped high biomass distribution.

• Journal of the Korean Vacuum Society
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• v.16 no.1
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• pp.7-14
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• 2007

A new horizontal neutron reflectometer has been designed and now under construction at the HANARO, 30 MW research reactor, in Daejon, Korea. We performed simulations of neutron ray-tracing to evaluate the performance of all of the optical components of the instrument with a Monte Carlo technique using McStas. The feasible wavelength of the incident neutron beam is $2.5{\AA}$. It produces a q-range up to $0.126{\AA}^{-1}$ with a supermirror as a deflector. Our studies showed improvement of the performance of the guide tube and monochromators. Although the performance is limited in q-range, it promises to be the first reflectometer in Korea for the study of free surfaces, which is currently in demand.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.7-13
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• 1978

Experiments were conducted to study the integrated control of one of the major pests of citrus, the citrus red mite, Panonychus citri (McGregor). Studies were conducted in Seogwipo, Cheju Island, 1973-1976. Results obtained were: 1. The major peak of citrus red mite occurrence was mid-July to mid-August. 2. Standard field populations of citrus red mite were also high in September, October, and November. 3. A total of 10 species of natural enemies of citrus red mite were found. These included; Oligota yasumatusi Kistner, Anystis baccarum L., Hemerobiid sp., Semidalis albate E., Orius sp., Agistemus terminalis Q., 3 species of lady beetles (Coccinellidae), and one unidentified species of predacious mite. 4. Annual occurrence of citrus med mite tended to decrease in unsprayed fields, but increased in fields receiving standard treatments. 5. With fungicides, there was an increase in mite populations associated with use of Bordeaux mixture and copperpowder sprays. Streptomycin, however, did not effect on increase in mite numbers.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.7.1-7.14
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• 2022

Background: Enterotoxigenic Escherichia coli (ETEC) infection is a primary cause of livestock diarrhea. Therefore, effective vaccines are needed to reduce the incidence of ETEC infection. Objectives: Our study aimed to develop a multivalent ETEC vaccine targeting major virulence factors of ETEC, including enterotoxins and fimbriae. Methods: SLS (STa-LTB-STb) recombinant enterotoxin and fimbriae proteins (F4, F5, F6, F18, and F41) were prepared to develop a multivalent vaccine. A total of 65 mice were immunized subcutaneously by vaccines and phosphate-buffered saline (PBS). The levels of specific immunoglobulin G (IgG) and pro-inflammatory cytokines were determined at 0, 7, 14 and 21 days post-vaccination (dpv). A challenge test with a lethal dose of ETEC was performed, and the survival rate of the mice in each group was recorded. Feces and intestine washes were collected to measure the concentrations of secretory immunoglobulin A (sIgA). Results: Anti-SLS and anti-fimbriae-specific IgG in serums of antigen-vaccinated mice were significantly higher than those of the control group. Immunization with the SLS enterotoxin and multivalent vaccine increased interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations. Compared to diarrheal symptoms and 100% death of mice in the control group, mice inoculated with the multivalent vaccine showed an 80% survival rate without any symptom of diarrhea, while SLS and fimbriae vaccinated groups showed 60 and 70% survival rates, respectively. Conclusions: Both SLS and fimbriae proteins can serve as vaccine antigens, and the combination of these two antigens can elicit stronger immune responses. The results suggest that the multivalent vaccine can be successfully used for preventing ETEC in important livestock.

• KSBB Journal
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• v.9 no.5
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• pp.532-540
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• 1994

Secretion efficiency is generally affected by promoter, signal sequence, characteristics of foreign protein and host. Secretion efficiencies of glucoamylase in recombinant plasmid-harboring yeast and chromosome-integrated yeast which had STA signal sequences were 74% and 65% at the 4th day of incubation, respectively. The high secretion efficiencies of the yeasts were obtained due to the fact that the expression levels were not reached at the secretory apparatus capacities of the host yeasts. In both yeasts, most of the intracellular glucoamylase were detected in cytoplasm and small portion (below 10%) of glucoamylase were located in periplasm. The characteristics of secreted heterologous glucoamylase from recombinant Saccharomyces cerevisiaes were investigated by using Western blot analysis. The secreted mature glucoamylase was heterogeneous and its molecular weight was about 200 to 300 kilodalton. The carbohydrate content of mature glucoamylase was higher than 80%, and several bands of about 55 to 65 kilodalton indicate the endoplasmic reticulum forms of intracellular glucoamylase.