• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.415-424
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• 2010

The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:87. A nonpolar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the ${\Delta}luxS$ mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxisrelated genes (flhD; fliA, C, D, S, Z; and cheA, Y, Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1427-1437
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• 2014

Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, ${\beta}$-glucosidase, xylanase, and ${\beta}$-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of ${\beta}$-glucosidase and core hemicellulases (xylanase and ${\beta}$-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external ${\beta}$-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.79-88
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• 2005

This research studied the utilization of the bed log wastes as a papermaking grade pulp. Five different bed log samples from shiitake mushroom (Lentinus edodes (Berk.) Sing) cultivation were collected by the cultivating periods of 1 to 5 years. The wood chemical composition and the characteristics of kraft pulping of each sample were investigated. The results of chemical composition showed that the rate of carbohydrate (glucose and xylose) content in sapwood was decreased as the cultivation period was increased. In heartwood, there was no significant difference. The screening yield of non-cultivated bed log from kraft pulping was higher than that of cultivated one, but the reject of cultivated one, especially for 5 year-cultivated, was lower than non-cultivated bed log. The fiber length and width was continuously decreased as the cultivation period was increased. Therefore, the freeness of the pulp from the cultivated bed log was sharply decreased comparing to non-cultivated due to the fiber cutting and the increased fine content. The dry strengths were increased according to the increasing addition level of bed log kraft pulp to KOCC and non-cultivated wood pulp. From the overall results, the pulp from 5 years cultivated bed log can be reasonably used if it is mixed with long fiber pulp for advantages such as reducing beating time.

• Food Science and Preservation
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• v.5 no.1
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• pp.57-63
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• 1998

To furnish basic data about the utilization of Korean loquat as flood, this experiment was conducted. Nutritional components in leaves, fruit excluded seed, flesh and seed of Korean loquat were analyzed as follows : moisture 48.7%, 87.8%, 88.3% and 59.5% ; total sugar 1.57%, 7.21%, 7.36% and 2.41% ; crude protein 5.23%, 1.61%, 1.44% and 4.31% in each portion, respectively. The highest mineral contents of loquat leaves, fruit excluded seed, flesh and seed were Ca 2,458ppm, K 661ppm, 654ppm and 1,528ppm, and water soluble vitamins such as ascorbic acid, thiamin and pyridoxine were confirmed in different pares of Korean loquat, the contents of those were high thiamin 5.86mg% in leaves and ascorbic acid 1.l0mg%, 1.26mg% and 4.90mg% in fruit excluded seed flesh and seed, respectively. The contents of free sugars were high sucrose 0.87%, glucose 0.62%, 0.6475 and rhamnose 0.20%, and major organic acid were detected oxalic acid 1,693.70mg%, malic acid 201.70mg%, 207.60mg% and citric acid 55.70mg% in each portion, respectively. Free amino acid were identified 21, 14, 14 and 16 kinds of leaves, fruit excluded seed, flesh and seed, respectively and their contents in each portion were highest glutamic acid 280.22mg%, proline 35.l0mg%, glutamic acid 56.96mg% and sarcosine 230.24mg%, respectively. Volatile components were identified 25 and 11 kinds of leaves and flesh and their contents were highest d-nerolidol 28.70ppm, hexadecanoic acid 16.67ppm, respectively.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.109-109
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• 2018

Bacillus subtilis B22, a chemotrophic and aerobic bacterial strain was isolated from homemade kimchi, identified by 16S rRNA gene sequencing. B22 was primarily screened by biochemical, carbon source utilization tests. B22 was used to produce pectinase and ${\beta}$-glucosidase by submerged fermentation under different light sources. B22 was incubated in pectin media and basal media (pH 7.0) under blue, green, red and white light-emitting diodes (LEDs), fluorescent white light, and in darkness at $37^{\circ}C$, orbital shaker 150 rpm for 24 hours. Fermentation under blue LEDs maximized pectinase production ($71.59{\pm}1.6U/mL$ at 24 h) and ${\beta}$-glucosidase production ($56.31{\pm}1.6U/mL$ at 24 h). Further, the production of enzyme increased to pectinase ($156{\pm}1.28U/mL$) and ${\beta}$-glucosidase ($172{\pm}1.28U/mL$) with 3% glucose as a carbon source. Activity and stability of the partially purified enzymes were higher at pH 6.0 to 8.0 and $25-55^{\circ}C$. The effect on the metal ions $Na^+$ and $K^+$ and (moderateactivity) $Mn^{2+}$ and $Ni^{2+}$ increased activity, while $Hg^{2+}$, $Cu^{2+}$, $Fe^{2+}$, and $Fe^{2+}$ inhibited activity. EDTA, phenylmethylsulfonyl fluoride and 5,5-dithiobis (2-nitrobenzoicacid) reduced activity, while tetrafluoroethylene and 1,10-phenanthroline inhibited activity. The amylase was highly tolerant of the surfactants TritonX-100, Tween-20, Tween-80 and compatible with organic solvents methanol, ethanol, isoamylalcohol, isopropanol, t-butylalcohol and the oxidizing agents hydrogen peroxide, sodium perborate and sodium hypochlorite, although potassium iodide and ammonium persulfate reduced activity. These properties suggest utility of pectinase and ${\beta}$-glucosidase produced by B. subtilis B22 under blue LED-mediated fermentation for industrial applications.

• Advances in Traditional Medicine
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• v.5 no.1
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• pp.1-15
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• 2005

Ginseng is a popular medicinal plant highly valued throughout the world. Asian ginseng is one of the most common species of ginseng. It has long occupied a significant position in oriental medicine and has been justified its name as the 'king herb'. As a nutritional supplement, ginseng is an extremely common and popular herbal medicine in the United States and Canada in recent decades. The multiple constituents of ginseng possess equally multifaceted pharmacological actions as demonstrated by numerous studies. Ginseng root and its constituents influenced the central nervous system, endocrine, cardiovascular, gastrointestinal system, sexual, renal organ and immune system, etc. One important action is its anti-hyperglycemic effect. Previous studies on ginseng demonstrate that only the root of ginseng has been used in the treatment of diabetes, while the other parts of ginseng plant were always neglected. Recently, we analyzed the constituents of ginseng berry, leaf and discovered that ginseng berry, leaf extracts and its total ginsenosides have the ability to reduce hyperglycemia and body weight and increase the peripheral glucose utilization in obese or diabetic ob/ob or db/db mice. Our data suggest that all parts of ginseng plant, including root, berry, leaf and stem exhibit potent anti-hyperglycemic and anti-obese effects and may provide an opportunity to develop a novel class of anti-diabetic agents.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.57-68
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• 1990

In order to obtain the fundamental informations on cellulase of Trichoderma viride QM 9414 for its production and utilization, some physico-chemical properties of the enzyme were reviewed. When T. viride QM 9414 was cultured on wheat bran medium, filter paper-disintegrating and carboxymethyl cellulose-saccharifying activity were increased with the cell growth, and thereafter CMC-saccharifying activity was kept on almost the same leved while filter-paper disintegrating activity was decreased sharply. And B-glucosidase was formed maximally on the late stationary phase of growth. The crude cellulase of cell-free extracts was purified by (NH4)2SO4 fractionation, Sephadex-G 200 column chromatography and DEAE Sephadex A-50 column chromatography. Filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity were purified 10-fold, 47-fold and 38-fold, respectively. The crude enzyme was proved to be a complex of three different enzyme proteins which were showing filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity. The optimal pH of the three enzyme components was alike pH 4.0, and the optimal temperature for CMC-saccharifying, filter paper-disintegrating and B-glucosidase activity were 4$0^{\circ}C$, 45$^{\circ}C$ and 5$0^{\circ}C$ respectively. The Km and Vmax values of CMC saccharifying activity for CMC were 0.485% and 3.10, and the Km and Vmax vallues of B-glucosidase for PNPG were 0.944$\times$10-3M and 0.097, respectively. The Km and Vmax values of filter paper-disintegrating activity for Avicel were determined to be 0.09% and 0.178, respectively. B-Glucosidase activity was competitively inhibited by glucose, and the Ki value for this enzyme was 3.54$\times$10-3M, CMC saccharifying activity was found to be greatly inhibited by cellobiose.

• Proceedings of the Korean Society of Crop Science Conference
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• 2007.04a
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• pp.65-73
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• 2007

The objective of this study is to understand how regulatory mechanisms respond to sugar status for more efficient carbon utilization and source-sink regulation in plants. So, we need to identify and characterize many components of sugar-response pathways for a better understanding of sugar responses. For this end, genes responding change of sugar status were screened using Arabidpsis cDNA arrays, and confirmed thirty-six genes to be regulated by sucrose supply in detached leaves by RNA blot analysis. Eleven of them encoding proteins for amino acid metabolism and carbohydrate metabolism were repressed by sugars. The remaining genes induced by sugar supply were for protein synthesis including ribosomal proteins and elongation factors. Among them, I focused on three hydrolase genes encoding putative $\beta$-galactosidase, $\beta$-xylosidase, and $\beta$-glucosidase that were transcriptionally induced in sugar starvation. Homology search indicated that these enzymes were involved in hydrolysis of cell wall polysaccharides. In addition to my results, recent transcriptome analysis suggested multiple genes for cell wall degradation were induced by sugar starvation. Thus, I hypothesized that enzyme for cell wall degradation were synthesized and secreted to hydrolyze cell wall polysaccharides producing carbon source under sugar-starved conditions. In fact, the enzymatic activities of these three enzymes increased in culture medium of Arabidopsis suspension cells under sugar starvation. The $\beta$-galactosidase encoded by At5g56870 was identified as a secretory protein in culture medium of suspension cells by mass spectrometry analysis. This protein was specifically detected under sugar-starved condition with a specific antibody. Induction of these genes was repressed in suspension cells grown with galactose, xylose and glucose as well as with sucrose. In planta, expression of the genes and protein accumulation were detected when photosynthesis was inhibited. Glycosyl hydrolase activity against galactan also increased during sugar starvation. Further, contents of cell wall polysaccharides especially pectin and hemicellulose were markedly decreased associating with sugar starvation in detached leaves. The amount of monosaccharide in pectin and hemicellulose in detached leaves decreased in response to sugar starvation. These results supported my idea that cell wall has one of function to supply carbon source in addition to determination of cell shape and physical support of plant bodies.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.988-1001
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• 1999

The rumen ecosystem is increasingly being recognized as a promising source of superior polysaccharide-degrading enzymes. They contain a wide array of novel enzymes at the levels of specific activities of 1,184, 1,069, 119, 390, 327 and $946{\mu}mol$ Reducing sugar release/min/mg protein for endoglucanase, xylanase, polygalactouronase, amylase, glucanase and arabinase, respectively. These enzymes are mainly located in the surface of rumen microbes. However, glycoside-degrading enzymes (e.g. glucosidase, fucosidase, xylosidase and arabinofuranosidase, etc.) are mainly located in the rumen fluid, when detected enzyme activities according to the ruminal compartments (e.g. enzymes in whole rumen contents, feed-associated enzymes, microbial cell-associated enzymes, and enzymes in the rumen fluid). Ruminal fungi are the primary contributors to high production of novel enzymes; the bacteria and protozoa also have important functions, but less central roles. The enzyme activities of bacteria, protozoa and fungi were detected 32.26, 19.21 and 47.60 mol glucose release/min/mL mediem for cellulose; 42.56, 14.96 and 64.93 mmol xylose release/min/mL medium after 48h incubation, respectively. The polysachharide-degrading enzyme activity of ruminal anaerobic fungi (e.g. Neocallimastix patriciarum and Piromyces communis, etc.) was much higher approximately 3~6 times than that of aerobic fungi (e.g. Tricoderma reesei, T. viridae and Aspergillus oryzae, etc.) used widely in industrial process. Therefore, the rumen ecosystem could be a growing source of novel enzymes having a tremendous potential for industrial applications.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.12
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• pp.1736-1743
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• 2014

This study was designed to test the effects of dietary distillers dried grain (DDG) level on the growth performance, feed utilization, body composition and antioxidant activity of juvenile red seabream (Pagrus major). Six isonitrogenous and isocaloric diets were formulated to contain 0%, 5%, 10%, 15%, 20%, and 25% DDG from rice (designated as DDG0, DDG5, DDG10, DDG15, DDG20, and DDG25), respectively. Juvenile red seabream averaging $10.1{\pm}0.05g$ were randomly distributed into 400-L tanks in a flow through systems. Three replicate groups of fish were fed one of the experimental diets to visual satiation two times a day for 10 weeks. Survival, weight gain, feed efficiency, protein efficiency ratio and hepatosomatic index of fish were not affected by dietary DDG levels (p>0.05). Proximate and amino acid composition of whole body in juvenile red seabream were not affected by dietary DDG levels (p>0.05). Plasma content of total protein, glucose, cholesterol, glutamic-pyruvic transaminase, phospholipid and triglyceride were not affected by dietary DDG levels (p>0.05). 1, 1-Diphenyl-2-picryl-hydrazyl radical and alkyl radical scavenging activities in plasma and liver of fish were not affected by dietary DDG levels (p>0.05). The results of this experiment suggest that DDG has the potential to replace plant origin ingredients such as wheat flour and corn gluten meal and could be used up to 25% in diet without incurring negative effects on the growth performance of juvenile red seabream.