• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.713-725
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• 2018

Lower termites require symbiotic microbes in their gut. The microbial communities in the termites must adapt to the termite temperature. Reticulitermes speratus KMT001 from Bukhan Mountain in Seoul may require a special symbiotic microorganisms for growth in low temperature Korean habitat. A metagenomics analysis showed a dramatic change in the symbiotic bacterial flora in the gut of R. speratus KMT001 in response to low temperatures of $4^{\circ}C$ or $10^{\circ}C$. Elusimicrobia, which are endosymbionts of flagellate protists, is the dominant phylum in the termite gut at ${\geq}15^{\circ}C$ but its population decreased drastically at low temperature. Four representative bacterial strains isolated from R. speratus KMT001 in a previous study produced maximum ${\beta}$-glucosidase levels within the temperature range of $10^{\circ}C-30^{\circ}C$. Elizabethkingia sp. BM10 produced ${\beta}$-glucosidase specifically at $10^{\circ}C$. This strain supported the existence of symbiotic bacteria for the low temperature habitat of the termite. This identified bacterium will be a resource for studying low temperature adaptation of termites, studying the gene expression at low temperatures, and developing an industrial cellulase at low temperature.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.526-529
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• 2002

Lysis of erythrocytes isolated from human, rabbit, and mouse blood samples was investigated with the culture supernatant of Xenorhabdus nematophilus in a primary form. Prior to use, the culture supernatant of the bacteria was concentrated and the concentrate was dialyzed against Tris-HCl buffer (10 mM, pH 8.1) by ultrafiltration using PM-5 membrane with a molecular weight cut-off of 5,000. At $30^{\circ}C$, the supernatant exhibited no lytic activity towards three types of erythrocytes. However, at $4^{\circ}C$, the supernatant showed selective lytic activity towards rabbit erythrocytes within 90 min. yet did not lyze human or mouse erythrocytes. Microscopic examination clearly revealed that most of the rabbit erythrocytes had been fumed into ghost forms.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.137-147
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• 2017

The human skin is an ecosystem that provides habitat to various microorganisms. These comprise the skin microbiome and provide numerous benefits in addition to maintaining a symbiotic relation with the host. Various metabolites generated by the skin microbiome exert beneficial effects such as strengthening the skin barrier, and anti-aging and anti-inflammatory functions. In this study, we isolated a novel bacterium, designated Sporichthyacae strain K-07, from the human skin. Analysis of 16S rRNA gene sequences showed that the newly found bacterium shares 93.4% homology with the genus Sporichthya, thus corroborating the discovery of a novel genus. We further analyzed the effect of the novel strain in vitro, by treating HaCaT cells with bacterial metabolite products. Treatment resulted in changes in the mRNA expression levels of filaggrin, claudin1, claudin4, SMase, CERS3, HAS3, aquaporin3, IL-6, TNF-${\alpha}$, TSLP, and TARC. Specifically, the levels of filaggrin, claudin1, claudin4, SMase, CERS3, HAS3, and aquaporin3 were higher in strain K-07 metabolite product-treated cells than in control cells. These results showed that metabolite products of the novel strain K-07 enhanced the skin barrier and exert anti-inflammatory effects. Therefore, these metabolite products could be potentially used for treatment of skin conditions.

• The Korean Journal of Soil Zoology
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• v.3 no.1
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• pp.19-24
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• 1998

The importance of the gut microorganism in the termite, Reticulitermes Speratus kyushuenesis Morimoto, was estimated by feeding with several antibiotics. Antibiotics which killed the bacterium, but not the fungi (Ampicillin, Kanamycin, Erythromycin), or killed both the microorganismw (Cephaloridine, Tetracycline) reduced the life span of the termite from 245 days to about 15 days. On the other hand, some antibiotics, penicillin and pimaricin, did not greatly reduce the life span of the termite.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.372-374
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• 2001

Three simple carboxamides incorporating the phenethylamine moiety have been isolated from strain XR-NC of a symbiotic bacterium Xenorhabdus nematophilus. Their structures were identified by spectroscopic data and synthesis. The compounds exhibited significant cytotoxicities against human cancer-cell line, viz. the gastric adenocarcinoma, colon adenocarcinoma and lung adenocarcinoma.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.22-27
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• 2001

It have been investigated how algal and bacterial symbiotic reaction influences on removal of organic carbon in river ecosystem. And artificial experimentation apparatus was made for algae'and bacteia'culture as lab scale. Investigating and researching minutely the change of concentration of organic carbon substrate and the change of population density of algae'and of bacteria'with this artificial experimentation apparatus, the next results could be obtained. 1. Successful decrease of DOC(dissolved organic carbon) could not be expected unless algal and bacterial biomass floe was nut formed effectively and unless biosorption was not proceeded effectively in the very culture system in which artificial synthetic wastewater was supplied continuously at constant rate. 2. In conditions of culture liquid of 1335 glucnse mg/L(type 1) and of 267 glucose mg:L(type 2), the algal dominant species was always Chlorella vulgaris in both types in which artificial synthetic wastewater were supplied continuously at constant rate and algae population density was around maximum 107 cells/mL. 3. It was around 108 ~ 107 cells/mL that the population density of heterotrophic bacterium. In culture medium systems type 1 and type 2 in which artificial wastewater were supplied continuously at constant rate, the same density appeared initially when using the population density of Escherichia coli w 3110 as indirect indicator. And this density decreased rapidly till the culturing date 35 days were passed away, while this density increased with gentle slope after same date and then the trend of change at type 2 was more severe than one at type 1. 4. When seeing such a change of population density of Escherichia coli w 3110, the growth of heterotrophic bacterium appeared as survival instinct pattern of broader requirement of nutrient at condition of low concentration of organic carbon substrate than condition of high concentration of same substrate.

• Korean journal of applied entomology
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• v.44 no.1 s.138
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• pp.21-30
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• 2005

Feeding behavior of foraging ants including visiting numbers, species, and preference on insect cadavers killed by entomopathogenic nematodes <(Heterorhabditis sp. KCTC 0991BP (He) and Steinernema carpocapsae KCTC 0981BP (Sc)> and their symbiotic bacteria was investigated in Dongrae Benest Golf Club, Anyang Benest Golf Club, Gapyung Benest Golf Club and Ulsan Golf Club. The number of ants, kinds and numbers of cadavers taken away by ants were different depending on killing method, golf club and site within the golf courses (fairway and rough). The feeding preference of ants was the lowest on cadavers killed by He. At Dongrae Benest Golf Club Lasius japonicu ($75{\pm}5\%$) and Monomorium floricola ($10\%$) took away cadavers only at the rough. The visiting rate of ants was $85{\pm}6\%$ at the rough, but none at the fairway by 16 hours. The taken rate of cadavers by ants was the lowest on He-killed cadavers representing $16.7\%$ compared with $40.0\%$ on Sc-killed cadavers, $53.3\%$ on fenitrithion-killed cadavers, and $56.7\%$ on natural dead cadavers by 12 hours. At the rough of hole 6 in Anyang Benest Golf Club, Tetramorium tsushimae ($33{\pm}12\%$), Pheidole fervida ($17{\pm}15\%$), Camponatus japonicus ($10\%$), Formica japonica ($7{\pm}6\%$), Paratrechina flavipes ($3{\pm}6\%$), and Crematogaster matsumurai ($3{\pm}6\%$) took away cadavers, but $23{\pm}15\%$ of cadavers were not visited by ants. Ants took away $40\%$ of Sc-killed cadavers, $16.7\%$ of frozen-killed cadavers, and $3.4\%$ of He-killed cadavers. The number of visiting ants was low at the hole 9 of Cherry course in Gapyung Benest Golf Club and only Tetramorium tsuhimae and Paratrechina flavipes were found from one site. The density of entomopathogenic nematodes did not influence ant visiting on cadavers, but burying affected ant visiting. Although ants took away unburied cadavers, buried cadavers were taken away at the hole 6 of Dongrae Benest Golf Club by 16 hours. Ant visiting had the same tendency on symbiotic bacterium-treated biscuit as nematode-killed cadavers. The visiting was less on biscuit inoculated by Photorhabdus sp., a symbiotic bacterium of He than on biscuit inoculated by Xenorhabdus nematophila, a symbiotic bacterium of Sc.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.515.1-515
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• 1986

Thermostable tryptophanase was extracted from a thermophilie bacterium, strain T which was absolutely symbiotic with strain 5. The enzyme was purified 14.7 fold with 5.8% yield by chromatographies using ion exchange, gel filtration, and hydrophobic interaction columns, followed by high performance liquid chromatography on hydroxyapatite column. The purified enzyme has a molecular weight of approximately 210,000 estimated by gel filtration column chromatography, and the molecular weight of subunit was determined by SDS polyacrylamide gel electrophoresis to be 46,000, which indicates that the native enzyme is made of four homologous subunits. The tryptophanase was stable at 65o0 and the optimum temperature for the enzyme activity for 20 min reaction was 70$^{\circ}C$. The purified enzyme activity for 20 min ieaction was 70$^{\circ}C$. The purified enzyme catalyzed the degradation of L-tryptophan into indole, pyruvate and ammonia in the presence of pyridoxal phosphate. 5-Hydroxy-Ltryptophan, 5-methyl-DL-tryptophan, L-cysteine, S-methyl-L-cysteine, 5-methyl-DL-tryptophan, L-cysteine, S-methyl-Lcysteine, and L-serine were also used as substrates to form pyruvate. The amino acid composition of the tryptophanase was determined, and found to contain a high percentage of hydrophobic amino acids, especially in the proline content, which was much higher than that of Escherichia coli tryptophanase. In addition, the 35N-terminal amino acid sequence of the tryptophanase was completely different from that of E. coli tryptophanase.

• Journal of Microbiology and Biotechnology
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• v.21 no.8
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• pp.869-873
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• 2011

Most medium formulations for improving culture of entomopathogenic nematodes (EPN) based on protein sources have used enriched media like animal feed such as dried egg yolk, lactalbumin, and liver extract, among other ingredients. Most results, however, showed unstable yields and longer production time. Many of the results do not show the detailed parameters of fermentation. Soy flour, cotton seed flour, corn gluten meal, casein powder, soytone, peptone, casein hydrolysates, and lactalbumin hydrolysate as protein sources were tested to determine the source to support optimal symbiotic bacteria and nematode growth. The protein hydrolysates selected did not improve bacterial cell mass compared with the yeast extract control, but soy flour was the best, showing 75.1% recovery and producing more bacterial cell number ($1.4{\times}10^9$/ml) than all other sources. The highest yield ($1.85{\times}10^5$ IJs/ml), yield coefficient ($1.67{\times}10^6$ IJs/g medium), and productivity ($1.32{\times}10^7$ IJs/l/day) were also achieved at enriched medium with soybean protein.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.67-70
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• 2001

Medicago truncatula is a diploid legume plant related to the forage crop alfalfa. Recently, it has been chosen as a model species for genomic studies due to its small genome, self-fertility, short generation time, and high transformation efficiency. M. truncatula engages in symbiosis with nitrogen-fixing soil bacterium Rhizobium meliloti. M. truncatula mutants that are defective in nodulation and developmental processes have been generated. Some of these mutants exhibited altered phenotypes in symbiotic responses such as root hair deformation, expression of nodulin genes, and calcium spiking. Thus, the genes controlling these traits are likely to encode functions that are required for Nod-factor signal transduction pathways. To facilitate genome analysis and map-based cloning of symbiotic genes, a bacterial artificial chromosome library was constructed. An efficient polymerase chain reaction-based screening of the library was devised to fasten physical mapping of specific genomic regions. As a genomics approach, comparative mapping revealed high levels of macro- and microsynteny between M. truncatula and other legume genomes. Expressed sequence tags and microarray profiles reflecting the genetic and biochemical events associated with the development and environmental interactions of M. truncatula are assembled in the databases. Together, these genomics programs will help enrich our understanding of the legume biology.