• Journal of Life Science
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• v.19 no.6
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• pp.744-750
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• 2009

A bacterial strain producing highly viscous extracellular polysaccharide was isolated from soil. Through morphological, physiological and chemotaxonomical studies, it was identified as a Bacillus sp. and named Bacillus sp. PS-12. The extracellular polysaccharide, named PS-12 was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation and gel permeation chromatography. The purified polysaccharide was found to consist of glucose, mannose, galactose, and fucose, with a molar ratio of approximately 7:3.2:2:1, respectively. PS-12 was investigated for its immunostimulating activity on murine macrophage RAW264.7 cells using an ELISA assay. PS-12 stimulated the production of TNF-${\alpha}$ to a level 50 times greater than the control and also induced 1L-6 secretion in a dose-dependent manner. The cytotoxicity on RAW264.7 cells by PS-12 was relatively low with 10% cytotoxicity at 2 ${\mu}g$/ml. These results indicate that PS-12 is less cytotoxic to immune cells and possess immunomodulating activity in which it can produce cytokines including TNF-${\alpha}$ and 1L-6 from macrophages.

• Molecules and Cells
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• v.25 no.4
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• pp.467-478
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• 2008

Simple sequence repeats (SSRs) and interSSR (ISSR) marker systems were used in this study to reveal genetic changes induced by artificial selection for short/long larval duration in the tropical strain Nistari of the silkworm Bombyx mori. Artificial selection separated longer larval duration (LLD) ($29.428{\pm}0.723days$) and shorter larval duration (SLD) ($22.573{\pm}0.839days$) lines from a base, inbred population of Nistari (larval span of $23.143{\pm}0.35days$). SSR polymorphism was observed between the LLD and SLD lines at one microsatellite locus, Bmsat106 ($CA_7$) and at two loci of 1074 bp and 823 bp generated with the ISSR primer UBC873. Each of these loci was present only in the LLD line. The loci segregated in the third generation of selection and were fixed in opposite directions. In the $F_2$ generation of the $LLD{\times}SLD$ lines, the alleles of Bmsat106 and $UBC873_{1074bp}$ segregated in a 1:1 ratio and the loci were present only in the LLD individuals. $UBC873_{823bp}$ was homozygous. Single factor ANOVA showed a significant association between the segregating loci and longer larval duration. Together, the two alleles contributed to an 18% increase in larval duration. The nucleotide sequences of the $UBC873_{1074bp}$ and $UBC873_{823bp}$ loci had 67% A/T content and consisted of direct, reverse, complementary and palindromic repeats. The repeats appeared to be "nested" (59%) in larger repeats or as clustered elements adjacent to other repeats. Of 203 microsatellites identified, dinucleotides (67.8%) predominated and were rich in A/T and T/A motifs. The sequences of the $UBC873_{1074bp}$ and $UBC873_{823bp}$ loci showed similarity (E = 0.0) to contigs located in Scaffold 010774 and Scaffold 000139, respectively, of the B. mori genome. BLASTN analysis of the $UBC873_{1074bp}$ sequence showed significant homology of (nt.) 45-122 with upstream region of three exons from Bombyx. The complete sequence of this locus showed ~49% nucleotide conservation with transposon 412 of Drosophila melanogaster and the Ikirara insertions of Anopheles gambiae. The A + T richness and lack of coding potential of these small loci, and their absence in the SLD line, reflect the active process of genetic change associated with the switch to short larval duration as an adaptation to the tropics.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.287-292
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• 2005

The crude galactomannans (GMs) were obtained from the culture of a newly isolated fungus Trichoderma erinaceum DG-312 and their anti-inflammatory activity was investigated in mice. The maximum concentrations of mycelial biomass and GMs reached 9.44 g/l, 2.72 g/l at day 3 in a 5-l stirred-tank bioreactor, respectively. The results of Sepharose CL-6B gel chromatography and compositional analysis revealed that the crude GMs contain heterogeneous polysaccharides consisting of $74.9\%$ mannose and $24.1\%$ galactose. The GMs was shown to possess a significant anti-inflammatory activity against acetic acid-induced inflammatory mouse model in a dose-dependent manner, when mice were treated with 100 and 200 mg GMs/kg body weight. The inhibition in vascular permeability $(60.6\%)$ and in writhing response $(62.5\%)$ evidenced an anti-inflammatory activity of the GMs. The marked anti-inflammatory and writhing-lowering properties of the GMs suggest its potential therapeutic use.

• Tunnel and Underground Space
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• v.19 no.4
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• pp.304-317
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• 2009

Most crystalline rocks have much higher compressive strength than tensile strength and show brittle failure. In-situ rock mass, strong enough in general sense, often fails in brittle manner when subjected to high stress exceeding strength in due of geometrically induced stress concentration or of high initial stress. Therefore, it is necessary to verify the brittle failure characteristics of rock and rock mass for proper stability assessment of underground structures excavated in great depths. In this study, damage controlled tests were conducted on biotite-granite and granitic gneiss, which are the two major crystalline rock types in Korea, to obtain the strain dependency characteristics of the cohesion and friction angle. A Cohesion-Weakening Friction-Strengthening (CWFS hereafter) model for each rock type was constructed and a series of compression tests were carried out numerically while varying confining pressures. The same tests were also conducted assuming the rock is Mohr-Coulomb material and results were compared.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.25-38
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• 1965

I. Breeding of tussah silkworm(preliminary report). The preliminary examination for bleeding has been carried out since 1963 in tussah silkworms. 1) The strain(l-MG-B)of the heaviest silk quantity was the green silkworm and brown cocoon in univoltine, and the strains(2-G-B, 2-MG-B) of the heaviest silk quantity were also the green silkwom and brown cocoon in bivoltine in both spring and fall in 1965. 2) It looks like the voltinism, the body color and the cocoon color have reached to pure line up to 1965. II. Best place for the winter of tussah pupa. This work was aimed to find out good ways for the winter of tussah pupa. 1) The hatch of bivoltine was better than that of univoltine. 2) The cocoons covered with the leaves were good in the emergence of moth. 3) The cocoons which were kept at natural temperature till the first emergence of moths would show bad in both hatch and emergence. 4) If some of the pupae kept under natural condition were controled at proper temperature for a few days, hatch and laying eggs were best. 5) The best places for the winter were the egg storage and the rearing room. III. Relation between incubation temperature and voltinism. 1) When the tussah pupa are kept at natural temperature during winter, the moths do not come out of the pupa. 2) There is no difference between about 18$^{\circ}C$ and about 25$^{\circ}C$ during incubation in hatching ratio. 3) The tussah silkworms of univoltine in mortality are stronger than that of bivoltine. 4) There is not any relation between voltinism and high or low temperature for pupa and eggs. IV. Induced mutation by gamma-ray and neutron in tussah silkworm. This work was carried out in order to induce the mutation by treating the pupa or the eggs of tussah silkworm with gamma my and neutron. The results obtained are as follows. 1. Though the whole pupa treated with neutron become moths, the moths have no ability to copulate each other. The only moths emerged from pupa treated with neutron, 4000${\gamma}$ are able to lay all un-fertilized eggs, some of which have a hole on the surface and nothing of contents. 2. The non-diapause eggs are treated with neutron in spring, but the hatching ratio is 50∼60 percent, but the whole eggs treated with gamma ray are never hatched. 3. The sensitivity of the pupa to neutron is weaker than that of the eggs. 4. The hatching ratio is in direct proportion to the gamma ray dose. 5. Author find out a new mutant which is excellent in the cocoon quality, so he will do the progeny test next hear.

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.149-158
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• 1995

The purpose of the present study was to understand the pathogenesis of infections in piglets inoculated with C parvum isolated from mice alone and combined with porcine rotavirus (S-80). Thirteen 10-day piglets were divided in four groups; Three, A group, were only given by C parvum. Four, B group, were orally administrated with firstly porcine rotavirus and then C patvum. Three, C group, were orally inoculated with porcine rotavirus alone. The rest, D group, were used as controls. During the experiment, there were daily recorded clinical signs including diarrhea to each pig. According to the periodic intervals for necropsy, all pigs were sacrificed from 4 to 12 days after the final inoculation of C parvum. Location and distribution of two pathogens, C parvum and rotavirus, in the intestinal mucosa of piglets tested were examined by pathological and immunohistological means. In addition, parasitological test using the feces of piglets was applied for the detection of cryptosporidial oocysts as well. A group showed diarrhea from 4 to 6 days post-inoculation(PI) and also discharged C parvum oocysts in feces during the day 4 to 7 PI. In tissue sections of jejunum and ileum, cryptosporidial oocysts were observed a few on the top of villi with slightly fusion. B group represented sign of diarrhea and discharge of oocysts from 2 to 11 days PI. There were some cryptosporidial oocysts both in the jejunal lumen and in the lumen of mucosal glands. As progressed, oocysts were most commonly distributed on the tip of villi of jejunum. Histopathologically there were also mild to moderately fused, attenuated focal desquamated, congested villi and mononuclear cell infiltration of varying degrees in the lamina propria of small intestine and colon at the day 4 and 7 PI. C group showed slightly to mildly attenuated and fused top of villi and mildly mucosal congestion. D group as controls was grossly and histopathologically normal in all parts of intestine. The present results indicate that the piglets inoculated with C parvum only are certainly milder in pathogenesis including duration of clinical course and severity of lesion than those in piglets concurrently infected with porcine rotavirus and C parvum. Also the strain (VRI-CN91) of C parvum used in the study has very low pathogenicity to occur enteritis of piglets.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.334-341
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• 2004

Polysaccharides were prepared from Orostachys japonicus by extration with hot steam water (OJPl). The OIPl fraction was further purified by Sephadex G-50 gel filtration chromatography to produce FI (polysaccharides) and FII (oligosaccharides) fraction. The average molecular masses o fFI and FII fraction were determined to be 3050 kDa and 13 kDa, respectively. The antimicrobial activity of OIPl was tested against 8 strains of bacteria and one strain of yeast by the disc diffusion method, fluorescein diacetate (FDA) method and broth dilution method. The OIPl exhibited a very strong growth inhibition to Candida albicans. The OIPl remarkably sup­pressed the growth of Salmonella typhimurium and Staphylococcus aureus. The OIPl showed higher growth inhibition to Escherichia coli and Pseudomonas aeruginosa than propolis, positive control. When the anticancer activity of the OIPl, FI or FII was examined against human cancer cell lines and the Sarcoma 180 cells, these widely suppressed the proliferation of cell lines in the MTT assay and morphology study. Especially, they remarkably inhibited the growth of A549, HeLa and AGS cells. Also treatment of cancer cells with OJPl, FI or FII induced apoptotic cell death characterized by DNA fragmentation. The OJPl, FI or FII exhibiting various biological activities such as antimicrobial activity and anticancer activity is expected to be developed as new biohealth products.

• Korean Journal of Microbiology
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• v.45 no.3
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• pp.268-274
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• 2009

A photosynthetic cyanobacterium Arthrospira platensis, well known for health food supplement, was studied as a target species for atmospheric $CO_2$ removal as well as biomass production. Although the biomass of A. platensis was massively produced in many countries, the recovery cost of its biomass is still high. The purpose of this study was to develop the A. platensis mutant strains which have enhanced growth rate and floatation activity to reduce the recovery cost. A. platensis KCTC AG20590 was treated with 0.24% ethyl methanesulfonate (EMS) for 20 min at room temperature. The mutant strain A. platensis M20CJK3 was finally selected by its morphological and physiological features. The morphology of the mutant A. platensis M20CJK3 was changed from loose-coiled form to tight-coiled form showing short pitch. The growth and $CO_2$ uptake rate of A. platensis M20CJK3 were improved about 15% and 17% compared with A. platensis KCTC AG20590, respectively. The floatation activity of A. platensis M20CJK3 was enhanced in 2-fold compared with that of A. platensis KCTC AG20590. Soluble proteins extracted from two strains were analyzed by two dimensional electrophoresis (2-DE) and MALDI-TOF MS/MS. Among 15 protein spots induced in 2-DE analysis, two spots were the proteins related to photosynthesis and electron transfer system of the other cyanobacteria. As a consequence, it seems that the tight-coiled mutant A. platensis M20CJK3 has an advantage of high growth rate and floatation activity which are beneficial for the mass cultivation and recovery.

• Journal of Animal Science and Technology
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• v.51 no.2
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• pp.171-176
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• 2009

A bacterial strain producing intracellular phytase was isolated from cultivable soil near cowsheds and identified as a fluorescent Pseudomonas sp. BUN1. The BUN1 phytase, partially purified by cation and anion exchange chromatography, exhibited its optimal activity at $40^{\circ}C$ and pH 5.5. As for substrate specificity, it was very specific for phytate and showed little activity on other phosphorylated conjugates. Its activity was greatly inhibited by metal ions such as $Cu^{2+}$, $Cd^{2+}$, and $Zn^{2+}$. Addition of corn starch to PSM (phytasesynthetic medium) [0.5% sodium phytate, 0.5% $(NH_4)_2SO_4$, 0.5% KCl, 0.01% $MgSO_4\cdot7H_2O$, 0.01% $CaCl_2\cdot2H_2O$, 0.01% NaCl, 0.001% $FeSO_4\cdot7H_2O$, 0.001% $MnSO_4\cdot4H_2O$; pH 6.5] for the phytase production significantly induced its enzyme activity in comparison with other carbon sources tested.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.527-533
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• 1992

The optimal conditions for cellulase and xylanase production by Trichoderma reesei 28217 were studied for enzymatic deinking of old newspaper. The amounts of cellulase and xylanase from the strain was varied by initial medium pH, Tween 80, inoculum size of spore suspension, and carbon and nitrogen sources. The optimal conditions for cellulase production were pH 5.0-6.5, 0.02% of Tween 80, 0.5-1.0% of inoculum size of spore suspension ($1{\times}10^{7}$/ml). cottonseed meal as nitrogen source, and corn flour as carbon source. On the other hand, the optimal conditions for xylanase production were pH 6.5, 0.01% of Tween 80, corn steep liquor as nitrogen source, and disintegrated old newspaper as carbon source. The inoculum size for xylanase production was the same as for cellulase production. The concomitant production of cellulase and xylanase in shake flask culture was efficiently induced in the medium containing 0.5% cottonseed meal as nitrogen source and 1.0% old newspaper and 2.0% corn flour as carbon sources. In this case the activities of cellulase and xylanase produced were 6.11-7.22 IU/mJ and 97.7 IU/ml. respectively. However, the cellulase production in $5{\ell}$ fermentor scale was slightly decreased compared with that in flask scale. Moreover, xylanase production was severely reduced in a fermentor scale. The study for the reason of decreased enzyme production in fermentor is further needed.