• International Journal of Stem Cells
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• v.17 no.1
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• pp.51-58
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• 2024

With the activity of intestinal stem cells and continuous turnover, the gut epithelium is one of the most dynamic tissues in animals. Due to its simple yet conserved tissue structure and enteric cell composition as well as advanced genetic and histologic techniques, Drosophila serves as a valuable model system for investigating the regulation of intestinal stem cells. The Drosophila gut epithelium is in constant contact with indigenous microbiota and encounters externally introduced "non-self" substances, including foodborne pathogens. Therefore, in addition to its role in digestion and nutrient absorption, another essential function of the gut epithelium is to control the expansion of microbes while maintaining its structural integrity, necessitating a tissue turnover process involving intestinal stem cell activity. As a result, the microbiome and pathogens serve as important factors in regulating intestinal tissue turnover. In this manuscript, I discuss crucial discoveries revealing the interaction between gut microbes and the host's innate immune system, closely associated with the regulation of intestinal stem cell proliferation and differentiation, ultimately contributing to epithelial homeostasis.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.10
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• pp.843-850
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• 2005

FBA(flux balance analysis) with Boolean rules for representing regulatory events has correctly predicted cellular behaviors, such as optimal flux distribution, maximal growth rate, metabolic by-product, and substrate concentration changes, with various environmental conditions. However, until now, since FBA has not taken into account a hierarchical regulatory network, it has limited the representation of the whole transcriptional regulation mechanism and interactions between specific regulatory proteins and genes. In this paper, in order to solve these problems, we describe the construction of hierarchical regulatory network with defined symbols and the introduction of a weight for representing interactions between symbols. Finally, the whole cellular behaviors with time were simulated through the linkage of a hierarchical regulatory network module and dynamic simulation module including FBA. The central metabolic network of E. coli was chosen as the basic model to identify our suggested modeling method.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.269-276
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• 2011

The aim of this study was to evaluate the effect of 3 environment- friendly farming materials on the growth of pepper and tomato seedlings under low level of solar radiation. The pepper and tomato seedlings were separately grown on commercial substrate and non-fertilizer substrate under 30% shading condition, respectively. The microbe-, enzyme-, and amino acid-supplements were used for the foliar application to the seedlings. The application of enzyme- and amino acid-supplements significantly enhanced the growth of tomato and pepper seedlings grown on non-fertilizer substrate, while there was no significant effect on the seedlings grown on commercial substrate. The foliar application of enzyme- and amino acid-supplements reduced the days to flowering by 3 to 4 days and lowered the node order of fruit set in tomato plants grown on non-fertilizer substrate. The results showed that the enzyme- and amino acid-supplements could enhance the seedling growth and lower the node order of fruit set under limited nutritional conditions.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.136-136
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• 2003

Calcium lactate has been known extending shelf-life of several lactic acid fermented foods through buffer action with lactic acid and binding of calcium and pectic polysaccharides in the tissue. But, the effects in kimchi during storage and distribution has not been observed. Calcium lactate is tasteless, nontoxic compounds commonly used in a number of food products. Recent observations have indicated the potential usefulness of calcium lactate as food additive which has anticariogenic-, antimicrobial-, anticalculus, anti- carcinogenic effects and enhancement of bone mineral density. In this work we determined the effects of calcium lactate(CaL)-treatment(0, 1, 2 and 3% against salted Chinese cabbage) on the pH, acidity, microbial counts, content of alcohol insoluble substance and calcium texture, color, scanning electron microscopic observation of kimchi tissue and sensory test during storage. pH of CaL treated kimchi were higher(3.78∼3.92) than that of control products(3.58). Total microbe(TM) of CaL treated kimchis were lower but ratio of lactic acid bacteria against TM was higher than those of control products, respectively. Calcium content of treated products were 3-5 times higher than control products. The hardness and crispy taste of treated products were remarkably higher than those of control products evaluated by SEM observation AIS analysis, sensory and textural analysis. Moreover, evaluation on the pH, acidity and sensory test showed the shelf-life of treated kimchi(CaL 2%) to be 25-30 days, which was 13-15 days longer than that of control products.

• Food Science and Preservation
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• v.9 no.4
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• pp.406-410
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• 2002

This study was conducted to investigate the effect of addition methods of green tea on the fermentation characteristics of kimchi. Kimchis were prepared to 3 methods such as Chinese cabbage soaked in brine containing 1％ of green tea extracts(Ⅰ), salted the cabbage soaked in water containing 1％ of green tea extracts(II), salted the cabbage mixed with seasonings containing 1％ of green tea extracts(Ⅲ), and fermented at l0$\^{C}$. pH of Ⅰ∼Ⅲ kimchis were higher than that of control kimchi during fermentation and its acidity showed the same tendency. Total microbe(5.40∼8.38 log cfu/mL) and the number of lactic acid bacteria(4.99∼8.07 log cfu/mL) in Ⅰ∼Ⅲ kimchis were lower than those of control kimchi(6.16∼9.29 and 4.59∼8.42 log cfu/mL). Lightness of kimchi tissue showed the order of Ⅰ＜II＜control＜Ⅲ. Sour taste and fishy taste of Ⅰ∼Ⅲ kimchis were lower than that of control kimchi. Overall quality was best in II estimated by sensory evaluation and fermentation characteristics.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.595-602
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• 2022

This study was conducted to investigate the characteristics of apple fermentation when different types of salt were used during apple fermentation, and when salt was added or not. The pH decreased in all experimental groups during the fermentation process, and the final pH was 4.72-3.31. The sugar content was 17.8-18.5 °Brix, the lowest in the sea salt (FAS), and the highest in the control group (FA). The acidity was measured as 0.48-0.56%, which was high in the control group (FA), and was 0.83-1.06% on the 7th day of final fermentation. The alcohol content was generated from the 5th day of fermentation, and the control group (FA) showed a distribution of 39.23-29.4%, and the alcohol content was higher in the control group than in the experimental group, As for the total polyphenol content and total DPPH content, it was confirmed that the purified salt (3.11 mg GAE/mL) showed the highest total polyphenol content than the control (2.25 mg GAE/mL). When salt was added, the fermentation progress was excellent, and when the salt concentration was high, it was confirmed that the possibility of apple fermentation was high.

• Research in Plant Disease
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• v.21 no.3
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• pp.161-179
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• 2015

Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.521-529
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• 2010

Two experiments were conducted to evaluate multi-microbe submerged liquid (SLF) and solid substrate (SSF) fermented probiotic products in broilers. The SLF and SSF probiotics were comprised of Lactobacillus acidophilus ($1.1{\times}10^9$ and $4{\times}10^8$ cfu/g), Bacillus subtilis ($1.1{\times}10^9$ and $4{\times}10^9$ cfu/g), Saccharomyces cerevisiae ($1.5{\times}10^7$ and $1.0{\times}10^4$ cfu/g) and Aspergillus oryzae ($2.6{\times}10^7$ and $4.3{\times}10^7$ cfu/g), respectively. In Exp. 1, 640 day-old Ross chicks were allotted to 4 treatments, each comprising 4 replicates (40 chicks/replicate). The basal diet was prepared without any antimicrobials (negative control, NC), and 20 mg/kg avilamycin (positive control, PC), 0.3% SLF and 0.3% SSF probiotics were added to the basal diets as treatments. Birds fed PC and SSF diets showed improved (p<0.001) overall weight gain and F/G than birds fed NC and SLF diets; whereas, birds fed SLF diet had better weight gain and F/G than birds fed NC diet. Retention of CP was higher (p<0.05) in birds fed the SSF diet than birds fed PC, SLF and NC diets. Birds fed the SLF diet tended to have higher (p<0.10) cecal total anaerobic bacteria than birds fed PC and NC diets; whereas, lesser cecal coliforms were noticed in birds fed PC, SLF and SSF diets than birds fed the NC diet. In Exp. 2, 640 day-old Ross chicks were randomly allotted to 4 treatments in a $2{\times}2$ factorial arrangement. Each treatment had 4 replicates (40 chicks/replicate). Two different multi-microbe probiotic products (0.3% SLF or SSF) each with two different antibiotics (10 mg/kg colistin, or 20 mg/kg avilamycin) were used as dietary treatments. Birds fed the SSF diet had greater weight gain (p<0.001), better F/G (p<0.05), greater retention of energy (p<0.001) and protein (p<0.05), and lesser cecal Clostridium (d 35) than birds fed SLF diet. Birds fed the colistin-supplemented diet had less (p<0.01) cecal coliforms when compared with birds fed the avilamycin diet. Additionally, birds fed the avilamycin diet had greater energy retention (p<0.05) than birds fed the colistin diet. Thus, the results of this study suggest the multi-microbe probiotic product prepared by a solid substrate fermentation method to be superior to the probiotic product prepared by submerged liquid fermentation; moreover, feeding of probiotics with different antibiotics did not elicit any interaction effect between probiotic and antibiotic.

• Journal of Environmental Health Sciences
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• v.31 no.3
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• pp.199-206
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• 2005

C. neoformans-associated cryptococcosis is primarily a disease of immunocompromised persons, has a world-wide distribution, and is often spread by pigeons in the urban environment. In contrast, C. gattii causes infection in normal hosts, has only been described in tropical and semi-tropical areas of the world, and has a unique niche in river gum Eucalyptus trees. Cryptococcosis is acquired through inhalation of the yeast propagules from the environment. C. gattii has been identified as the cause of an emerging infectious disease centered on Vancouver Island, British Columbia, Canada. No cases of C. gattii-disease were diagnosed prior to 1999; the current incidence rate is 36 cases per million population. A search was initiated in 2001 to find the ecological niche of this basidiomycetous yeast. C. gattii was found in the environment in treed areas of Vancouver Island. The highest percentage of colonized-tree clusters were found around central Vancouver Island, with decreasing rates of colonization to the north and south. Climate, soil and vegetation cover of this area, called the Coastal Douglas fir biogeoclimatic zone, is unique to British Columbia and Canada. The concentration of airborne C. gattii was highest in the dry summer months, and lowest during late fall, winter, and early spring, months which have heavy rainfall. The study of the emerging colonization of this organism and subsequent cases of environmentally acquired disease will be informative in planning public health management of new routes of exposure to exotic agents in areas impacted by changing climate and land use patterns.