Eu Jin Chung

Gyeongsang National University, Chinju, South Gyeongsang, South Korea

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Publications (16)36.77 Total impact

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    ABSTRACT: An endophytic, Gram-negative bacterium was isolated from sterilized roots of a plant, Suaeda maritima, growing on tidal flats. Cells of the strain were motile by means of a single polar flagellum and colonies were light brown pigmented. Strain YC6927T was able to grow at 15-37 °C (optimum at 28-30 &°C) and at pH 5.0-10.0 (optimum at pH 7.0-8.0). The strain was able to grow at NaCl concentrations of 0-9.0 % (w/v) with an optimum growth at 0-5.0 % NaCl. Comparison of 16S rRNA gene sequences showed that the strain was a member of the genus Labrenzia, exhibiting the highest similarity with Labrenzia marina KCTC 12288T (97.6 % sequence similarity). Strain YC6927T produced light brown carotenoid pigments. The major respiratory quinone was Q-10 and the DNA G+C content was 58.5 mol%. The DNA-DNA relatedness values between strain YC6927T and closely related strains were between 8.2±1.8-20.3±1.5 %. Chemotaxonomically, strain YC6927T contained C18: 1ω7c and C14: 0 3-OH as major fatty acids, confirming the affiliation of strain YC6927T with the genus Labrenzia. The polar lipids comprised of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, an unknown aminolipid, an unknown phospholipid and five unknown lipids. On the basis of phylogenetic analysis, physiological and biochemical characterization and DNA-DNA hybridization data, strain YC6927T should be classified as a novel species of the genus Labrenzia, for which the name Labrenzia suaedae sp. nov. is proposed. The type strain is YC6927T (=KACC 13772T =DSM 22153T). An emended description of the genus Labrenzia is also proposed.
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 01/2014; · 2.11 Impact Factor
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    ABSTRACT: A novel bacterial strain YC6899(T) was isolated from the root of Suaedae maritima growing at tidal flat of Namhae Island, Korea. Cells are Gram-negative, rod-shaped, non-motile, moderately halophilic and heterotrophic. Strain YC6899(T) grew optimally at a salinity of 2-4 %, at 25-37 °C and pH 6.5-8.0. Phylogenetic analysis of 16S rRNA gene sequences demonstrated that strain YC6899(T) was closely related to Amorphus orientalis YIM D10(T) (96.1 %) and Amorphus coralli RS.Sph.026(T) (95.9 %). The polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), unknown aminolipids, unknown aminophospholipid, unknown aminoglycolipid, unknown glycolipids and unknown lipids. The major fatty acids of strain YC6899(T) were C19:0 cyclo ω8c (66.9 %) and C18:1 ω7c (16.7 %). The G+C content of the genomic DNA was 61.3 mol%. Strain YC6899(T) contained ubiquinone-10 (Q-10) as the major respiratory quinone system. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain YC6899(T) represents a novel species within the genus Amorphus, for which the name Amorphus suaedae sp. nov. is proposed. The type strain is YC6899(T) (= KACC 14912(T) = NBRC 107845(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 05/2013; · 2.11 Impact Factor
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    ABSTRACT: A Gram-staining-negative, rod-shaped, aerobic bacterial strain designated YC7003T, was isolated from a rotten-wood piece collected at Jinju, Korea. The taxonomic position of the strain was investigated by a polyphasic approach. The strain was catalase- and oxidase-positive, grew at 4-35°C (optimum, 30°C) and at pH 5.0-10.0 (optimum, pH 6.5-7.0). The major cellular fatty acids were C16:1ω7c and/or iso-C15:0 2-OH (35.1%), iso-C15:0 (27.5%) and C16:1ω5c (11.7%) and the major respiratory quinone was MK7. The total genomic DNA G+C content was 49.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YC7003T belonged to the genus Mucilaginibacter in the family Sphingobacteriaceae with 94.4-97.2% sequence similarities with reported type strains of the genus Mucilaginibacter. The most closely related species was Mucilaginibacter mallensis MP1X4T (97.2%). The DNA-DNA relatedness value between strain YC7003T and M. mallensis MP1X4T was 21.7±3.3%. Based on these polyphasic data, strain YC7003T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter gynuensis sp. nov. is proposed. The type strain is YC7003T (=KACC 15532T=JCM 17705T).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 03/2013; · 2.11 Impact Factor
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    ABSTRACT: A Gram-negative, non-spore forming endophytic bacterium, designated strain YC6887T, was isolated from a root sample of a halophyte, Rosa rugosa collected from a tidal flat area of Namhae Island, located at southern end of Korea. Strain YC6887T was found to exhibit inhibitory activity against oomycete plant pathogens. The cells were non-motile and aerobic rods. The strain was able to grow at 4-40 °C (optimum at 28-30 °C) and at pH 5.0-9.0 (optimum at pH 7.0-8.5). Strain YC6887T was able to grow at NaCl concentrations of 0-9 % (w/v) with optimum growth at 4-5 % (w/v) NaCl, but NaCl is not essential for growth. Comparison of 16S rRNA gene sequences showed that the strain was a member of the genus Martelella, a member of order Rhizobiales, exhibiting highest similarity with Martelella mediterranea (98.6 %). The DNA-DNA relatedness between strain YC6887T and M. mediterranea MACL11T was 19.8±6.8. Chemotaxonomically, strain YC6887T contained C19:0 cyclo ω8c (28.0 %) and C18: 1ω7c (17.9 %) as predominant fatty acids, confirming the affiliation of strain YC 6887T with genus Martelella . The major respiratory quinone was Q-10 and the DNA G+C content was 62.1 mol%. On the basis of phylogenetic analysis, physiological and biochemical characterization, DNA-DNA hybridization data, strain YC6887T should be classified as representing a novel species of the genus Martelella, for which the name Martelella endophytica sp. nov. is proposed. The type strain is YC6887T (=KCCM 43011T NBRC 109149T).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 01/2013; · 2.11 Impact Factor
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    ABSTRACT: A Gram-negative, aerobic, short rod bacterium, designated strain YC6898(T), was isolated from the surface-sterilized root of a halophyte (Suaeda maritima) inhabiting tidal flat of Namhae Island, Korea. Strain YC6898(T) grew optimally at 30-37°C and pH 6.5-7.5. The strain inhibited mycelial growth of Pythium ultimum and Phytophthora capsici. The phylogenetic analyses based on 16S rRNA gene sequences indicated that strain YC6898(T) belongs to the genus Hoeflea in the family Phyllobacteriaceae. Most closely related species are Hoeflea alexandrii AM1V30(T) (96.7 %), Hoeflea anabaenae WH2K(T) (95.7 %), Hoeflea phototrophica DFL-43(T) (95.5%) and Hoeflea marina LMG 128(T) (94.8%). Strain YC6898(T) contained Q-10 as the major ubiquinone. The major fatty acids of strain YC6898(T) were C(18 : 1)ω7c (61.1 %), C(16 : 0) (11.9 %), 11-Methyl C(18 : 1)ω7c (9.6 %) and C(19 : 0) cyclo ω8c (8.0 %). The polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, unknown lipids and unknown glycolipid. The total genomic DNA G+C content was 53.7 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analysis, strain YC6898(T) represents a novel species of the genus Hoeflea, for which the name Hoeflea suaedae sp. nov. is proposed. The type strain is YC6898(T) (= KACC 14911(T) = NBRC 107700(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 11/2012; · 2.11 Impact Factor
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    ABSTRACT: A Gram-negative, rod-shaped, pale-orange pigmented bacterial strain with xylan degrading activity designated as YC7004(T) was isolated from a rotten-wood sample collected at Jinju, Korea and its taxonomic position was investigated by using a polyphasic approach. The strain grew optimally on R2A medium at 30°C and at pH 6. Major isoprenoid quinone was MK7 and major fatty acids were Summed feature 3, iso-C(15:0), C(16:0), iso-C(17:0) 3-OH, iso-C(17:1)ω9c and C(16:1)ω5c. The G+C content of the genomic DNA was 40.0 mol%. Phylogenetic analyses based on the 16S rRNA gene sequences showed that the strain belongs to the genus Mucilagenibacter in the family Sphingobacteriaceae. The most closely related species were Mucilaginibacter daejeonensis (95.5 %), Mucilaginibacter frigoritolerans (94.6 %) and Mucilaginibacter mallensis (94.0 %). Based on the phylogenetic and chemotaxonomic data analysis, the strain YC7004(T) represents a novel species of the genus Mucilaginibacter with the proposed name as Mucilaginibacter jinjuensis sp. nov. The type strain is YC7004(T) (=KACC 16571(T)=NBRC 108856(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 07/2012; · 2.11 Impact Factor
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    ABSTRACT: A novel bacterial strain, YC7001(T), was isolated from the rhizosphere soil of rice collected at Jinju, Korea and was characterized using a polyphasic approach. Cells of strain YC7001(T) were Gram-negative, yellow-pigmented, rod-shaped, aerobic, heterotrophic and non-motile. Strain YC7001(T) grew optimally at 25-30 °C, pH 5.0-8.0 and degraded gelatin, cellulose and chitin. The phylogenetic analyses based on 16S rRNA gene sequences indicated that strain YC7001(T) belongs to the genus Chitinophaga in the family Chitinophagaceae. Most closely related species are Chitinophaga sancti NBRC 15057(T) (96.9 %), Chitinophaga ginsengisoli Gsoil 052(T) (95.9 %), Chitinophaga pinensis DSM 2588(T) (95.7 %), Chitinophaga filiformis IFO 15056(T) (95.7 %), and Chitinophaga niabensis JS13-10(T) (95.0 %). DNA-DNA relatedness value of strain YC7001(T) with C. sancti NBRC 15057(T) was 15.2±0.6 %. Strain YC7001(T) contained MK-7 as the major menaquinone and homospermidine as the major polyamine. The major fatty acids of strain YC7001(T) were C(15 : 0) iso, C(16 : 1)ω5c and C(17 : 0) iso 3-OH. The polar lipids were phosphatidylethanolamine, unknown aminolipids and unknown lipids. The total genomic DNA G+C content was 41.3 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analysis, strain YC7001(T) represents a novel species of the genus Chitinophaga in the family Chitinophagaceae, for which the name Chitinophaga oryziterrae sp. nov. is proposed. The type strain is YC7001(T) (= KACC 14533(T) = JCM 16595(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 02/2012; · 2.11 Impact Factor
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    ABSTRACT: During a study of endophytic bacteria from coastal dune plants, a bacterial strain, designated YC6881(T), was isolated from the root of Rosa rugosa collected from the coastal dune areas of Namhae Island, Korea. The bacterium was found to be Gram-staining-negative, motile, halophilic and heterotrophic with a single polar flagellum. Strain YC6881(T) grew at temperatures of 4-37 °C (optimum, 28-32 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0), and at NaCl concentrations in the range of 0-7.5% (w/v) (optimum, 4-5% NaCl). Strain YC6881(T) was catalase- and oxidase-positive and negative for nitrate reduction. According to phylogenetic analysis using 16S rRNA gene sequences, strain YC6881(T) belonged to the genus Rhizobium and showed the highest 16S rRNA gene sequence similarity of 96.9% to Rhizobium rosettiformans, followed by Rhizobium borbori (96.3%), Rhizobium radiobacter (96.1%), Rhizobium daejeonense (95.9%), Rhizobium larrymoorei (95.6%) and Rhizobium giardinii (95.4%). Phylogenetic analysis of strain YC6881(T) by recA, atpD, glnII and 16S-23S intergenic spacer (IGS) sequences all confirmed the phylogenetic arrangements obtained by using 16S rRNA gene sequences. Cross-nodulation tests showed that strain YC6881(T) was a symbiotic bacterium that nodulated Vigna unguiculata and Pisum sativum. The major components of the cellular fatty acids were C(18:1)ω7c (53.7%), C(19:0) cyclo ω8c (12.6%) and C(12:0) (8.1%). The DNA G+C content was 52.8 mol%. Phenotypic and physiological tests with respect to carbon source utilization, antibiotic resistance, growth conditions, phylogenetic analyses of housekeeping genes recA, atpD and glnII, and fatty acid composition could be used to discriminate strain YC6881(T) from other species of the genus Rhizobium in the same sublineage. Based on the results obtained in this study, strain YC6881(T) is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium halophytocola sp. nov. is proposed. The type strain is YC6881(T) ( = KACC 13775(T) = DSM 21600(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 10/2011; 62(Pt 8):1997-2003. · 2.11 Impact Factor
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    ABSTRACT: A Gram-negative, non-spore-forming, endophytic bacterium, strain YC6886(T), was isolated from the root of a halophyte, Rosa rugosa, which inhabits coastal areas of Namhae Island off the southern coast of Korea. Cells were non-motile, obligately aerobic rods and formed pale-yellow colonies. The isolate grew at 4-32 °C (optimum 25-28 °C) and at pH 6.5-9.5 (optimum pH 7.5) and grew optimally with 2-3 % (w/v) NaCl, but NaCl was not an absolute requirement for growth. Strain YC6886(T) produced yellow carotenoid pigments. Strain YC6886(T) exhibited the highest 16S rRNA gene sequence similarity with Haloferula sargassicola MN1-1037(T) (97.4 %). Sequence similarities between strain YC6886(T) and other members of the genus Haloferula were 93.9-94.7 %. DNA-DNA relatedness between strain YC6886(T) and H. sargassicola KCTC 22202(T) and Haloferula rosea KCTC 22201(T) was 27 and 15 %, respectively. The major fatty acids were iso-C(14 : 0), C(16 : 0) and C(16 : 1)ω9c and minor components were C(14 : 0), C(18 : 0) and anteiso-C(15 : 0). The major respiratory quinone was menaquinone 9 and the DNA G+C content was 58.5 mol%. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unknown phospholipid and an unknown phosphoglycolipid. On the basis of phenotypic, chemotaxonomic, DNA-DNA hybridization and phylogenetic analysis, strain YC6886(T) represents a novel species in the genus Haloferula, for which the name Haloferula luteola sp. nov. is proposed. The type strain is YC6886(T) ( = KCTC 22447(T)  = DSM 21608(T)). An emended description of the genus Haloferula is also presented.
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 08/2011; 61(Pt 8):1837-41. · 2.11 Impact Factor
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    ABSTRACT: A Gram-stain-positive endophytic bacterium, designated strain YC6957(T), was isolated from surface-sterilized roots of a halophyte (Elymus mollis Trin.) inhabiting coastal tidal flats of Namhae Island, located on the southern coast of Korea, and was subjected to a polyphasic taxonomic study. Cells were facultatively anaerobic, endospore-forming rods to coccoid rods, motile by a single flagellum. Strain YC6957(T) was catalase-positive, oxidase-negative and able to grow in the presence of 0-8 % (w/v) NaCl, with optimum growth at 4-5 % (w/v) NaCl. Growth occurred at 15-45 °C (optimal growth at 30-35 °C) and pH 6.0-8.5 (optimal growth at pH 7.0-8.0). The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major cellular fatty acids were C(16 : 0) (11.3 %), iso-C(15 : 0) (19.2 %) and anteiso-C(15 : 0) (36.4 %). The cell-wall peptidoglycan contained meso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 41.6 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate belonged to the genus Bacillus. Strain YC6957(T) exhibited high 16S rRNA gene sequence similarity to its closest neighbours, Bacillus ruris LMG 22866(T) (96.14 %), Bacillus lentus NCIMB 8773(T) (95.97 %) and Bacillus galactosidilyticus LMG 17892(T) (95.91 %), and less than 95.84 % similarity to all other type strains in the genus Bacillus. On the basis of the phylogenetic, physiological and biochemical data, it is suggested that strain YC6957(T) represents a novel species of the genus Bacillus, for which the name Bacillus graminis sp. nov. is proposed. The type strain is YC6957(T) ( = KACC 13779(T)  = DSM 22162(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 07/2011; 61(Pt 7):1567-71. · 2.11 Impact Factor
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    ABSTRACT: Two Gram-reaction-negative, yellow-orange-pigmented, rod-shaped bacterial strains, designated YC6722(T) and YC6723(T), were isolated from rhizosphere soil samples collected from rice fields in Jinju, Korea. Strains YC6722(T) and YC6723(T) grew optimally at 25-30 °C and at pH 7.0-8.5. Phylogenetic analyses of 16S rRNA gene sequences showed that strain YC6722(T) was most closely related to Sphingomonas jaspsi TDMA-16(T) (96.6 % sequence similarity) and strain YC6723(T) was related most closely to Sphingomonas aquatilis JSS7(T) (96.9 %). The two strains contained ubiquinone-10 (Q-10) as the major respiratory quinone system and sym-homospermidine as the major polyamine. The G+C contents of the genomic DNA of strains YC6722(T) and YC6723(T) were 63.3 and 61.0 mol%, respectively. The major fatty acid was C(18 : 1)ω7c. The polar lipids detected in the two strains were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, sphingoglycolipid, phosphatidyldimethylethanolamine and other unknown lipids. On the basis of their phylogenetic positions, and their biochemical and phenotypic characteristics, strains YC6722(T) and YC6723(T) represent two novel species of the genus Sphingomonas, for which the names Sphingomonas oryziterrae sp. nov. ( = KCTC 22476(T)  = DSM 21455(T)) and Sphingomonas jinjuensis sp. nov. (KCTC 22477(T)  = DSM 21457(T)) are proposed.
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 11/2010; 61(Pt 10):2389-94. · 2.11 Impact Factor
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    ABSTRACT: A Gram-negative, rod-shaped bacterial strain, YC6729(T), was isolated from vermicompost collected at Masan, Korea, and its taxonomic position was investigated by a polyphasic taxonomic approach. Strain YC6729(T) grew optimally at 30 °C and at pH 6.5-8.5. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YC6729(T) belongs to the genus Chitinophaga in the family Chitinophagaceae. It was related most closely to Chitinophaga terrae KP01(T) (96.4 % 16S rRNA gene sequence similarity), Chitinophaga ginsengisegetis Gsoil 040(T) (96.1 %), Chitinophaga arvensicola IAM 12650(T) (96.1 %) and Chitinophaga pinensis DSM 2588(T) (93.3 %). Strain YC6729(T) contained MK-7 as the major menaquinone and homospermidine as the major polyamine. The fatty acids of strain YC6729(T) were iso-C(15 : 0), C(16 : 1)ω5c, iso-C(17 : 0) 3-OH, C(16 : 0), anteiso-C(18 : 0) and/or C(18 : 2)ω6,9c, iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c, C(14 : 0), iso-C(15 : 0) 3-OH, iso-C(15 : 1) G, C(18 : 1)ω5c, iso-C(15 : 1) I and/or C(13 : 0) 3-OH, C(13 : 0) 2-OH, C(16 : 0) 3-OH and unknown fatty acid ECL 13.565. The polar lipid profile contained phosphatidylethanolamine, unknown aminolipids and unknown lipids. The total DNA G+C content of strain YC6729(T) was 48.9 mol%. The phenotypic, chemotaxonomic and phylogenetic data showed that strain YC6729(T) represents a novel species of the genus Chitinophaga, for which the name Chitinophaga eiseniae sp. nov. is proposed. The type strain is YC6729(T) ( = KACC 13774(T)  = DSM 22224(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 11/2010; 61(Pt 10):2373-8. · 2.11 Impact Factor
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    ABSTRACT: A Gram-staining-positive, coccoid to rod-shaped bacterium, designated strain YC6903(T), was isolated from a halophytic plant (Carex scabrifolia Steud.) collected from sand dunes at Namhae Island, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain YC6903(T) grew optimally at 30 °C and at pH 8.0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YC6903(T) belongs to the genus Nocardioides in the family Nocardioidaceae. Strain YC6903(T) was related most closely to Nocardioides pyridinolyticus OS4(T) (97.0 % 16S rRNA gene sequence similarity), Nocardioides dokdonensis FR1436(T) (96.6 %), Nocardioides aquiterrae GW-9(T) (96.6 %) and Nocardioides hankookensis DS-30(T) (96.6 %). The cell-wall peptidoglycan contained LL-diaminopimelic acid and MK-8(H(4)) was the major respiratory quinone. The mean (±SD) level of DNA-DNA relatedness between strain YC6903(T) and N. pyridinolyticus OS4(T) was 53.5±5.5 %. The predominant cellular fatty acid of strain YC6903(T) was iso-C(16 : 0) (28.9 %). The DNA G+C content was 71.7 mol%. Phenotypic, phylogenetic and chemotaxonomic data indicated that strain YC6903(T) represents a novel species of the genus Nocardioides, for which the name Nocardioides caricicola sp. nov. is proposed. The type strain is YC6903(T) (=KACC 13778(T) =DSM 22177(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 02/2010; 61(Pt 1):105-9. · 2.11 Impact Factor
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    ABSTRACT: Using two forest soils, we previously constructed two fosmid libraries containing 113,700 members in total. The libraries were screened to select active antifungal clones using Saccharomyces cerevisiae as a target fungus. One clone from the Yuseong pine tree rhizosphere soil library, pEAF66, showed S. cerevisiae growth inhibition. Despite an intensive effort, active chemicals were not isolated. DNA sequence analysis and transposon mutagenesis of pEAF66 revealed 39 open reading frames (ORFs) and indicated that eight ORFs, probably in one transcriptional unit, might be directly involved in the expression of antifungal activity in Escherichia coli. The deduced amino acid sequences of eight ORFs were similar to those of the core genes encoding type II family polyketide synthases, such as the acyl carrier protein (ACP), ACP synthases, aminotransferase, and ACP reductase. The gene cluster involved in antifungal activity was similar in organization to the putative antibiotic production locus of Pseudomonas putida KT2440, although we could not select a similar active clone from the KT2440 genomic DNA library in E. coli. ORFs encoding ATP binding cassette transporters and membrane proteins were located at both ends of the antifungal gene cluster. Upstream ORFs encoding an IclR family response regulator and a LysR family response regulator were involved in the positive regulation of antifungal gene expression. Our results suggested the metagenomic approach as an alternative to search for novel antifungal antibiotics from unculturable soil bacteria. This is the first report of an antifungal gene cluster obtained from a soil metagenome using S. cerevisiae as a target fungus.
    Applied and Environmental Microbiology 03/2008; 74(3):723-30. · 3.95 Impact Factor
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    ABSTRACT: A metagenome is a unique resource to search for novel microbial enzymes from the unculturable microorganisms in soil. A forest soil metagenomic library using a fosmid and soil microbial DNA from Gwangneung forest, Korea, was constructed in Escherichia coli and screened to select lipolytic genes. A total of seven unique lipolytic clones were selected by screening of the 31,000-member forest soil metagenome library based on tributyrin hydrolysis. The ORFs for lipolytic activity were subcloned in a high copy number plasmid by screening the secondary shortgun libraries from the seven clones. Since the lipolytic enzymes were well secreted in E. coli into the culture broth, the lipolytic activity of the subclones was confirmed by the hydrolysis of p-nitrophenyl butyrate using culture broth. Deduced amino acid sequence analysis of the identified ORFs for lipolytic activity revealed that 4 genes encode hormone-sensitive lipase (HSL) in lipase family IV. Phylogenetic analysis indicated that 4 proteins were clustered with HSL in the database and other metagenomic HSLs. The other 2 genes and 1 gene encode non-heme peroxidase-like enzymes of lipase family V and a GDSL family esterase/lipase in family II, respectively. The gene for the GDSL enzyme is the first description of the enzyme from metagenomic screening.
    Journal of Microbiology and Biotechnology 11/2007; 17(10):1655-60. · 1.40 Impact Factor
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    ABSTRACT: A microbial community analysis of forest soil from Jindong Valley, Korea, revealed that the most abundant rRNA genes were related to Acidobacteria, a major taxon with few cultured representatives. To access the microbial genetic resources of this forest soil, metagenomic libraries were constructed in fosmids, with an average DNA insert size of more than 35 kb. We constructed 80,500 clones from Yuseong and 33,200 clones from Jindong Valley forest soils. The double-agar-layer method allowed us to select two antibacterial clones by screening the constructed libraries using Bacillus subtilis as a target organism. Several clones produced purple or brown colonies. One of the selected antibacterial clones, pJEC5, produced purple colonies. Structural analysis of the purified pigments demonstrated that the metagenomic clone produced both the pigment indirubin and its isomer, indigo blue, resulting in purple colonies. In vitro mutational and subclonal analyses revealed that two open reading frames (ORFs) are responsible for the pigment production and antibacterial activity. The ORFs encode an oxygenase-like protein and a putative transcriptional regulator. Mutations of the gene encoding the oxygenase canceled both pigment production and antibacterial activity, whereas a subclone carrying the two ORFs retained pigment production and antibacterial activity. This finding suggests that these forest soil microbial genes are responsible for producing the pigment with antibacterial activity.
    Applied and Environmental Microbiology 01/2006; 71(12):7768-77. · 3.95 Impact Factor

Publication Stats

111 Citations
36.77 Total Impact Points

Institutions

  • 2008–2013
    • Gyeongsang National University
      • • Plant Molecular Biology and Biotechnology Research Center
      • • Division of Applied Life Science
      Chinju, South Gyeongsang, South Korea
  • 2006–2008
    • Dong-A University
      • College of Natural Resources and Life Science
      Pusan, Busan, South Korea
  • 2007
    • Korea Research Institute of Chemical Technology
      Daiden, Daejeon, South Korea