Jeesun Chun

Flavobacterium aciduliphilum sp. nov., isolated from freshwater, and emended description of the genus Flavobacterium.

A Gram-stain-negative, rod-shaped, non-motile and yellow-pigmented bacterial strain, designated strain JJ013(T), was isolated from an artificial lake in Jeollabuk-do, South Korea, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain JJ013(T) indicated that the isolate belonged to the family Flavobacteriaceae and exhibited similarity levels of 96.6 % to the type strains of Flavobacterium cheonanense and Flavobacterium koreense and 96.5 % to the type strain of Flavobacterium chungnamense. Growth was observed at 20-30 °C and pH 5.0-7.0. The major cellular fatty acids of the novel strain were iso-C15 : 0 (27.5 %), iso-C15 : 1 G (17.8 %), iso-C17 : 0 3-OH (9.4 %) and iso-C15 : 0 3-OH (9.2 %). Flexirubin-type pigments were present. The DNA G+C content of strain JJ013(T) was 33.9 mol%, the major respiratory quinone was menaquinone-6 (MK-6) and the major polyamine was sym-homospermidine. The polar lipid profile of the strain JJ013(T) consisted of a phosphatidylethanolamine (PE), two unknown aminolipids (AL1-2), three unidentified lipid (L1-3) and an unknown glycolipid (GL). On the basis of the morphological and physiological properties and biochemical evidence presented, it is concluded that strain JJ013(T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium aciduliphilum sp. nov. is proposed; the type strain is JJ013(T) ( = KACC 16594(T) = JCM 18211(T)). Since C15 : 0, which is known as a predominant fatty acid of the genus Flavobacterium was not detected in the novel strain and other reference strains, we propose an emended description of the genus Flavobacterium.

Hymenobacter koreensis sp. nov. and Hymenobacter saemangeumensis sp. nov., isolated from estuarine water

Two Gram-reaction-negative, rod-shaped, non-motile and red-pink-pigmented bacterial strains, designated GYR3077(T) and GSR0100(T), were isolated from a water sample of the Mangyung estuary enclosed by the Saemangeum Embankment in JEOLlabuk-do, South Korea, and were characterized using a polyphasic approach. 16S rRNA genes of strains GYR3077(T) and GSR0100(T) exhibited sequence similarities of 95.9 % to Hymenobacter deserti ZLB-3(T) and 96.6 % to Hymenobacter soli PB17(T), respectively, and indicated that these isolates belonged to the phylum Bacteroidetes. The major cellular fatty acids present in the two isolates were iso-C15 : 0, C16 : 1ω5c, summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major respiratory quinone and polyamine patterns were menaquinone-7 and sym-homospermidine, characteristic of the genus Hymenobacter. Flexirubin-type pigments were absent in both strains. The DNA G+C contents of strains GYR3077(T) and GSR0100(T) were 60.2 mol% and 61.9 mol%, respectively. The major polar lipid of strains GYR3077(T) and GSR0100(T) was phosphatidylethanolamine. Based on the morphological and physiological properties, strains GYR3077(T) and GSR0100(T) were considered to represent two novel species of the genus Hymenobacter, for which the names Hymenobacter koreensis sp. nov. (type strain GYR3077(T) = KACC 16451(T) = JCM 17924(T)) and Hymenobacter saemangeumensis sp. nov. (type strain GSR0100(T) = KACC 16452(T) = JCM 17923(T)) are proposed.

Pontibacter saemangeumensis sp. nov., isolated from seawater

A gram-negative, rod-shaped, non-motile and pink bacterial strain, designated strain GCM0142(T), was isolated from the confined seawater in the Saemangeum Tide Embankment of South Korea, and characterized using a polyphasic approach. 16S rRNA gene sequence analysis of strain GCM0142(T) indicated that the isolate belonged to the phylum Bacteroidetes and exhibited similarity levels of 94.0-96.4 % to the type strains of recognized Pontibacter species. Strain GCM0142(T) was oxidase- and catalase-positive. The major cellular fatty acids of the novel strain were summed feature 4 (comprising iso-C(17 : 1)I and/or anteiso-C(17 : 1)B, 36.8 %), iso-C(15 : 0) (22.3 %) and summed feature 3 (comprising C(16 : 1)ω7c and/or C(16 : 1)ω6c, 6.2 %). The DNA G+C content of strain GCM0142(T) was 48.9 mol% and the major quinone was MK-7. The polar lipid profile consisted of phosphatidylethanolamine, two unknown aminolipids (AL1-2), an unknown aminophospholipid, five unknown lipids (L1-5) and an unknown glycolipid. On the basis of the evidence presented, strain GCM0142(T) is considered to represent a novel species of the genus Pontibacter, for which the name Pontibacter saemangeumensis sp. nov. is proposed. The type strain is GCM0142(T) ( = KACC 16448(T) = JCM 17926(T)).

The MpkB MAP kinase plays a role in autolysis and conidiation of Aspergillus nidulans

The mpkB gene of Aspergillus nidulans encodes a MAP kinase homologous to Fus3p of Saccharomyces cerevisiae which is involved in conjugation process. MpkB is required for completing the sexual development at the anastomosis and post-karyogamy stages. The mpkB deletion strain could produce conidia under the repression condition of conidiation such as sealing and even in the submerged culture concomitant with persistent brlA expression, implying that MpkB might have a role in timely regulation of brlA expression. The submerged culture of the deletion strain showed typical autolytic phenotypes including decrease in dry cell mass (DCM), disorganization of mycelial balls, and fragmentation of hyphae. The chiB, engA and pepJ genes which are encoding cell wall hydrolytic enzymes were transcribed highly in the submerged culture. Also, we observed that the enzyme activity of chitinase and glucanase in the submerged culture of mpkB deletion strain was much higher than that of wild type. The deletion of mpkB also caused a precocious germination of conidia and reduction of spore viability. The expression of the vosA gene, a member of velvet gene family, was not observed in the mpkB deletion strain. These results suggest that MpkB should have multiple roles in germination and viability of conidia, conidiation and autolysis through regulating the expression of vosA and brlA.

Flaviaesturariibacter amylovorans gen. nov., sp. nov., a starch-hydrolysing bacterium, isolated from estuarine water.

A novel bacterial strain, designated GCR0105(T), was isolated from a water sample of the Mangyung estuary enclosed by the Saemangeum Embankment, located in JEOLlabuk-do, South Korea. Cells of strain GCR0105(T) were Gram-stain-negative, non-motile and rod-shaped. Colonies of strain GCR0105(T) were pale yellow-pigmented on R2A agar and nutrient agar media, and were able to grow at 15-30 °C (optimum 25 °C) and pH 6.5-8.5 (optimum pH 7.5). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain GCR0105(T) was related most closely to Flavisolibacter ginsengisoli Gsoil 643(T) (93.14% similarity). The polar lipid profile of strain GCR0105(T) comprised phosphatidylethanolamine, two unknown aminolipids, an unknown aminophospholipid and four unknown lipids. The DNA G+C content of strain GCR0105(T) was 42.9 mol% and the respiratory quinone was MK-7.On the basis of phenotypic, chemotaxonomic and phylogenetic properties, strain GCR0105(T) represents a novel species in a new genus within the family Chitinophagaceae, for which the name Flaviaesturariibacter amylovorans gen. nov., sp. nov. is proposed. The type strain of Flaviaesturariibacter amylovorans is GCR0105(T) ( = KACC 16454(T) = JCM 17919(T)).

Flavobacterium fontis sp. nov., isolated from freshwater.

A taxonomic study was carried out on a novel bacterial strain, designated MIC3010(T), which was isolated from a freshwater pond in Jeonju, Republic of Korea. Cells of the isolate were Gram-stain-negative, rod-shaped and non-motile. Comparison of the 16S rRNA gene sequences indicated that the isolate belonged to the family Flavobacteriaceae, with Flavobacterium haoranii LQY-7(T) as its closest relative, with a similarity of 94.2 %. The predominant fatty acids of strain MIC3010(T) were iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. The polar lipid profile of strain MIC3010(T) revealed the presence of phosphatidylethanolamine (PE) and one unidentified lipid (L1) as major components. In addition, two aminolipids (AL1, AL2) and one glycolipid were present in small amounts. The DNA G+C content of the strain was 41.0 mol%. The strain contained MK-6 as the major quinone and sym-homospermidine as the predominant polyamine. On the basis of the evidence presented, it is concluded that strain MIC3010(T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium fontis sp. nov. is proposed. The type strain is MIC3010(T) ( = KACC 16593(T) = JCM 18212(T)).

Dyadobacter jejuensis sp. nov., isolated from seawater.

A taxonomic study was carried out on a novel bacterial strain, designated AM1R11(T), which was isolated from seawater of Jeju Island in Korea. Cells of the isolate were found to be Gram-negative, rod-shaped and non-motile. Comparison of the 16S rRNA gene sequences indicated that the isolate belonged to the family Cytophagaceae, with Dyadobacter ginsengisoli Gsoil 043(T) as its closest relative, with a similarity of 96.6 %. It contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 36.9 %), iso-C15 : 0 (16.5 %) and C16 : 1ω5c (16.3 %) as the major fatty acids and MK-7 as the predominant menaquinone. The polar lipid profile of strain AM1R11(T) revealed the presence of phosphatidylethanolamine, one aminolipid and four unidentified lipids (L1, L2, L3 and L4). The DNA G+C content of strain AM1R11(T) was 45.1 mol%. On the basis of the evidence presented, it is concluded that strain AM1R11(T) represents a novel species of the genus Dyadobacter, for which the name Dyadobacter jejuensis sp. nov. is proposed. The type strain is AM1R11(T) ( = KACC 16446(T) = JCM 17918(T)).

Pedobacter pituitosus sp. nov., isolated from a waterfall

A taxonomic study was carried out on a novel bacterial strain, designated MIC2002(T), which was isolated from Wibong falls in Korea. Cells were Gram-stain-negative, aerobic, non-motile and rods, 0.3-0.5 µm wide and 4.0-5.0 µm long. The optimum temperature and pH range for growth were 25 °C and pH 6.5-7.0, respectively. Catalase and oxidase activities were positive. Flexirubin pigments were not produced. Comparison of the 16S rRNA gene sequences indicated that the isolate belonged to the genus Pedobacter, with Pedobacter daechungensis as its closest relative, with a similarity of 94.4%. It contained iso-C(15:0), anteiso-C(15:0), C(16:0), summed feature 3 (C(16:1)ω6c and/or C(16:1)ω7c) and iso-C(17:0) 3-OH as the major fatty acids and menaquinone MK-7 as isoprenoid quinone. The polar lipid profile of strain MIC2002(T) revealed the presence of phosphatidylethanolamine and an unknown lipid. The DNA G+C content of the strain was 34.7 mol%. On the basis of the evidences presented, it was concluded that strain MIC2002(T) represents a novel species of the genus Pedobacter within the family Sphingobacteriaceae, for which the name Pedobacter pituitosus sp. nov. is proposed. The type strain is MIC2002(T) ( =KACC 17064(T) =JCM 18729(T)).

Psychroflexus salarius sp. nov., isolated from Gomso salt pan.

A taxonomic study was carried out on a novel bacterial strain, designated MIC1008(T), which was isolated from the Gomso salt pan, located in Buan County, Korea. Cells were Gram-stain-negative, aerobic, non-motile and moderately halophilic rods, 0.2-0.4 µm wide and 0.7-1.2 µm long. The optimum temperature and pH for growth were 25 °C and pH 6.5-8.5, respectively. Catalase and oxidase activities were positive. Carotenoid pigments were produced. Comparison of 16S rRNA gene sequences indicated that the isolate belonged to the genus Psychroflexus, with Psychroflexus halocasei WCC 4520(T) as its closest relative, with a 16S rRNA gene sequence similarity of 95.4%. The isolate contained iso-C15:0, iso-C15:1 G, iso-C17:0 3-OH, anteiso-C15:0 and iso-C15:0 3-OH as the major fatty acids and menaquinone MK-6 as the isoprenoid quinone. The major polar lipid profile of strain MIC1008(T) revealed the presence of phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The DNA G+C content of the isolate was 32.9 mol%. On the basis of the evidences presented, it is concluded that strain MIC1008(T) represents a novel species of the genus Psychroflexus within the family Flavobacteriaceae, for which the name Psychroflexus http://dx.doi.org/10.1601/nm.8182 salarius sp. nov. is proposed. The type strain is MIC1008(T) ( = KACC 17063(T) = DSM 25661(T)).

Nibribacter koreensis gen. nov., sp. nov., isolated from estuarine water

A Gram-reaction-negative, rod-shaped, non-motile, red-pigmented bacterium, designated strain GSR3061(T), was isolated from a water sample of the Mangyung estuary enclosed by the Saemangeum Embankment in JEOLlabuk-do of South Korea, and characterized using a polyphasic approach. 16S rRNA gene sequence analysis of strain GSR3061(T) indicated that the isolate belonged to the phylum Bacteroidetes and exhibited similarity levels of 94.7 % to Rufibacter tibetensis NRRL B-51285(T), 92.4 % to Adhaeribacter terreus KACC 14257(T) and 91.9 % to Pontibacter korlensis KACC 15371(T). Growth was observed at 15-40 °C and pH 6.5-9.5. The major cellular fatty acids of the novel strain were summed feature 4 (comprising iso-C17 : 1 I and/or anteiso-C17 : 1 B), iso-C15 : 0, C17 : 1ω6c and iso-C16 : 1 H. Flexirubin-type pigments were absent. The DNA G+C content of strain GSR3061(T) was 44.9 mol% and the major quinone was MK-7. The polar lipid profile consisted mainly of phosphatidylethanolamine; three unidentified lipids, two unknown aminolipids, two unknown phospholipids, an unknown aminophospholipid and an unknown glycolipid were also present. On the basis of the evidence presented, it is concluded that strain GSR3061(T) represents a novel species of a new genus, for which the name Nibribacter koreensis gen. nov., sp. nov. is proposed. The type strain of Nibribacter koreensis is GSR3061(T) ( = KACC 16450(T) = JCM 17917(T)).