Marinobacterium boryeongense sp. nov., isolated from seawater.

A Gram-stain-negative and strictly aerobic bacterium, designated DMHB-2T, was isolated from a sample of seawater collected off the Yellow Sea coast of the Republic of Korea. Cells were short rods and motile by means of a single polar flagellum. Catalase and oxidase activities were positive. Growth occurred at pH 5.5-10.0 (optimum, pH 6.0), 15-45 °C (optimum, 25 °C) and with 1-9 % NaCl (optimum, 3 %). The respiratory quinone was ubiquinone-8 and the major fatty acids were C16 : 0 (17.9 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 26.1 %) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 37.4 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain DMHB-2T belong to the genus Marinobacterium, with the highest 16S rRNA gene sequence similarity of 95.2 % to Marinobacterium zhoushanense KCTC 42782T. The genomic DNA G+C content of strain DMHB-2T was 60.8 mol%. On the basis of the phenotypic, chemotaxonomic and genotypic characteristics presented in this study, strain DMHB-2T is suggested to represent a novel species of the genus Marinobacterium, for which the name Marinobacteriumboryeongense sp. nov. is proposed. The type strain is DMHB-2T (=KACC 19225T=JCM 31902T).

Gemmobacter straminiformis sp. nov., isolated from an artificial fountain.

A Gram-stain-negative, non-motile and facultative anaerobic bacterium, designated CAM-8T, was isolated from an artificial fountain at Chonbuk National University, South Korea. The novel strain grew at 20-37 °C (optimum 25 °C), pH 5.5-7.0 (optimum 6.0) and with 0-2 % NaCl (optimum 0 %). Oxidase and catalase activities were positive. The cell morphology of strain CAM-8T was atypical rods 0.6-0.8 µm in width and 4.5-6.5 µm in length, with a peaked tip and sometimes a bulb shape. CAM-8T existed as single cells, and as pairs or chains of cells. The phylogenetic analysis of 16S rRNA gene sequences indicated that strain CAM-8T clustered with Gemmobacter nectariphilus JCM 11959T and Gemmobactermegaterium JCM 18498T within the genus Gemmobacter. The DNA G+C content of strain CAM-8T was 65.9 mol%. The respiratory quinone was ubiquinone Q-10. The major fatty acids were C18 : 1ω7c and/or C18 : 1ω6c. The polar lipids of strain CAM-8T consisted of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, two uncharacterized phospholipids, an uncharacterized aminolipid, an uncharacterized glycolipid, an uncharacterized aminophospholipid and four uncharacterized lipids. On the basis of phenotypic, phylogenetic and chemotaxonomic data, strain CAM-8T (=KACC 19224T=JCM 31905T) is considered to represent a novel species of the genus Gemmobacter, for which the name Gemmobacter straminiformis sp. nov. is proposed.

Uliginosibacterium flavum sp. nov. isolated from an artificial lake.

A Gram-negative, facultative anaerobic, rod-shaped, motile by means of a polar flagellum, greenish-yellow-pigmented bacterial strain (designated strain JJ3220T) was isolated from an artificial lake in South Korea and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain JJ3220T indicated that the isolate belongs to the family Rhodocyclaceae, and that it exhibits 96.4% similarity to Uliginosibacterium paludis KBP-13T. The major cellular fatty acids of the novel strain were C14:0, C16:0, and summed feature 3 (C16:1 ω6c and/or C16:1 ω7c). Strain JJ3220T had flexirubin-type pigments. The DNA G+C content of the strain was 62.8%. The major respiratory quinone and major polar lipid of strain JJ3220T were ubiquinone-8 and phosphatidylethanolamine, respectively. Based on the morphological and physiological properties and biochemical evidence presented, it can be concluded that strain JJ3220T represents a novel species of the genus Uliginosibacterium. The type strain Uliginosibacterium flavum is JJ3220T (=KACC 17644T =JCM 19465T).

Viridibacterium curvum gen. nov., sp. nov., isolated from freshwater.

A Gram stain-negative, yellowish green-pigmented, facultatively anaerobic, motile, curved rod-shaped bacterium designated as strain JJ016T was isolated from an artificial lake in South Korea, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain JJ016T indicated that the isolate belonged to the family Rhodocyclaceae and exhibited 95.0% identity to Uliginosibacterium gangwonense 5YN10-9T. The major cellular fatty acids of the novel strain were summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), C16:0, C14:0, and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). The DNA G+C content of strain JJ016T was 61.9 mol%. The major respiratory quinone and major polar lipid of strain JJ016T were ubiquinone-8 and phosphatidylethanolamine, respectively. Based on the morphological and physiological properties and the biochemical evidence presented, we concluded that strain JJ016T represents a novel species of a new genus in the family Rhodocyclaceae, for which the name Viridibacterium curvum gen. nov., sp. nov. is proposed. The type strain is JJ016T (=KACC 16899T =JCM 18715T).

Antimicrobial Effects and Resistant Regulation of Magnolol and Honokiol on Methicillin-Resistant Staphylococcus aureus.

The antimicrobial killing activity toward methicillin-resistant Staphylococcus aureus (MRSA) has been a serious emerging global issue. In a continuing search for compounds with antibacterial activity against several microorganisms including S. aureus and MRSA, an n-hexane extract of Magnolia officinalis was found to contain magnolol. This compound exhibited potent activity against S. aureus, standard methicillin-susceptible S. aureus (MSSA), and MRSA as well as clinical MRSA isolates. When combined with oxacillin, the antibacterial activities of magnolol and honokiol against the MRSA strain were increased compared to single treatment without antibiotics at 10 µg/mL and 25 µg/mL, respectively. These activities of magnolol and honokiol were dose dependent. Also, magnolol showed synergistic effects with oxacillin against 13 clinical isolates of MRSA. It was determined that magnolol and honokiol had a synergistic effect with oxacillin against MRSA strain. Furthermore, the magnolol inhibited the expression of the resistant genes, mecA, mecI, femA, and femB, in mRNA. We concluded that the antibacterial activity of magnolol against MRSA strain is more related to the mecI's pathway and components of the cell wall than mecR1. Therefore, the results obtained in this study suggest that the combination of magnolol and antibiotics could lead to the development of new combination antibiotics against MRSA infection.

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)).

Characterization of NpgA, a 4'-phosphopantetheinyl transferase of Aspergillus nidulans, and evidence of its involvement in fungal growth and formation of conidia and cleistothecia for development.

The null pigmentation mutant (npgA1) in Aspergillus nidulans results in a phenotype with colorless organs, decreased branching growth, delayed of asexual spore development, and aberrant cell wall structure. The npgA gene was isolated from A. nidulans to investigate these pleiomorphic phenomena of npgA1 mutant. Sequencing analysis of the complementing gene indicated that it contained a 4'-phosphopantetheinyl transferase (PPTase) superfamily domain. Enzymatic assay of the PPTase, encoded by the npgA gene, was implemented in vivo and in vitro. Loss-of-function of LYS5, which encoded a PPTase in Saccharomyces cerevisiae, was functionally complemented by NpgA, and Escherichia coli-derived NpgA revealed phosphopantetheinylation activity with the elaboration of 3'5'-ADP. Deletion of the npgA gene caused perfectly a lethal phenotype and the absence of asexual/sexual sporulation and secondary metabolites such as pigments in A. nidulans. However, a cross feeding effect with A. nidulans wild type allowed recovery from deletion defects, and phased-culture filtrate from the wild type were used to verify that the npgA gene was essential for formation of metabolites needed for development as well as growth. In addition, forced expression of npgA promoted the formation of conidia and cleistothecia as well as growth. These results indicate that the npgA gene is involved in the phosphopantetheinylation required for primary biological processes such as growth, asexual/sexual development, and the synthesis of secondary metabolites in A. nidulans.

Biosorption of cationic basic dye and cadmium by the novel biosorbent Bacillus catenulatus JB-022 strain.

Biosorption of heavy metals and dyes is a promising technology that involves the removal of toxic metals from industrial wastes. The present study aims to screen the bacterial strains isolated from soils and polluted pond for their potential biosorption of both cationic dye and cadmium. Bacillus catenulatus JB-022 strain removed 58% and 66% of cationic basic blue 3 (BB3) and cadmium (Cd(II)) at the respective concentrations of 2000 mg/L and 150 mg/L. The biosorption equilibrium data were well fitted by the Langmuir adsorption isotherm, and the kinetic studies indicated that the biosorption followed the pseudo-second-order model. The biosorption kinetics showed that the equilibrium was reached within 10 min and 5 min for BB3 and Cd(II), respectively. According to the Langmuir model, the maximum uptakes of BB3 and Cd(II) by the JB-022 biomass were estimated to be 139.74 and 64.28 mg/g, respectively. To confirm the surface morphology and functional groups, field emission scanning electron microscope, energy-dispersive X-ray spectrometer, X-ray diffraction, and Fourier transform infrared spectroscopy analyses were carried out, and the results revealed that the biomass of JB-022 has carboxyl and phosphonate groups as potential surface functional groups capable of binding to cationic pollutants. In conclusion, B. catenulatus JB-022 is proposed as an excellent biosorbent with potentially important applications in removal of cationic pollutants from wastewaters.

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)).

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.

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)).

Nibrella saemangeumensis gen. nov., sp. nov. and Nibrella viscosa sp. nov., novel members of the family Cytophagaceae, isolated from seawater.

Two strains, designated GCR0103(T) and GYR3121(T), were isolated from seawater of the Saemangeum Embankment in Jeollabuk-do, Korea. The cells of the two strains were Gram-reaction-negative and non-motile, and formed multicellular filaments. The colonies of the two strains were pink-pigmented and able to grow at 15-37 °C (optimum 25 °C) on R2A and NA medium. Strains GCR0103(T) and GYR3121(T) grew at pH 6.5-10 (optimum pH 7.5) and pH 5.5-9.5 (optimum pH 7.5), and within NaCl ranges of 0-0.4% and 0-1%, respectively. The polar lipid profiles of the two strains contained phosphatidylethanolamine, five unknown aminolipids, an unknown phospholipid and four or five unknown lipids. The DNA G+C contents of strains GCR0103(T) and GYR3121(T) were 56.0 and 54.5 mol%, respectively. The respiratory quinone detected in both strains was MK-7. The 16S rRNA gene sequence similarity between GCR0103(T) and GYR3121(T) was 95.5 %. The 16S rRNA gene sequence similarities of the two strains to closely related reference strains were less than 89 %. Phylogenetic analysis based on 16S rRNA genes showed that GCR0103(T) and GYR3121(T) formed a distinct phyletic line in the family Cytophagaceae. On the basis of the phenotypic, chemotaxonomic and phylogenetic properties, strains GCR0103(T) and GYR3121(T) represent two novel species in a new genus within the family Cytophagaceae, for which the names Nibrella saemangeumensis gen. nov., sp. nov. and Nibrella viscosa sp. nov. are proposed. The type strain of Nibrella saemangeumensis is GCR0103(T) ( = KACC 16453(T) = JCM 17927(T)) and the type strain of Nibrella viscosa is GYR3121(T) ( = KACC 16447(T) = JCM 17925(T)).

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.

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)).

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)).

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.

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 post-karyogamy processes as well as in hyphal anastomosis during sexual development in Aspergillus nidulans.

Two genes encoding MAP kinase homologs, designated as mpkB and mpkC, were isolated from Aspergillus nidulans by PCR with degenerate primers. Deletion and over-expression mutants of mpkC showed no detectable phenotypes under any external stress tested. Deletion of mpkB caused pleiotropic phenotypes including a failure in forming cleistothecia under any induction conditions for sexual development, increased Hülle cell production, slow hyphal growth and aberrant conidiophore morphology. Over-expression of mpkB led to increased cleistothecium production. While the transcripts of mpkB and mpkC were constitutively synthesized through the entire life cycle, their size and amount differed with developmental stages. An outcross test using fluorescent protein reporters showed that the mpkB deletion mutant could not form heterokaryons with wild type. Protoplast fusion experiments showed that the fusant of the mpkB mutant with wild type could undergo normal sexual development. However, heterokaryotic mycelia that were produced from a fusant between two mpkB deletion mutants could not form cleistothecia, although they did appear to form diploid nuclei. These results suggest that the MpkB MAP kinase is required for some post-karyogamy process as well as at the hyphal anastomosis stage to accomplish sexual development successfully.

Predicting the chemical composition and structure of Aspergillus nidulans hyphal wall surface by atomic force microscopy.

In fungi, cell wall plays an important role in growth and development. Major macromolecular constituents of the aspergilli cell wall are glucan, chitin, and protein. We examined the chemical composition and structure of the Aspergillus nidulans hyphal wall surface by an atomic force microscope (AFM). To determine the composition of the cell wall surface, the adhesion forces of commercially available beta-glucan, chitin, and various proteins were compared to those of corresponding fractions prepared from the hyphal wall. In both setups, the adhesion forces of beta-glucan, chitin, and protein were 25-50, 1000-3000, and 125-300 nN, respectively. Adhesion force analysis demonstrated that the cell surface of the apical tip region might contain primarily chitin and beta-glucan and relatively a little protein. This analysis also showed the chemical composition of the hyphal surface of the mid-region would be different from that of the apical region. Morphological images obtained by the tapping mode of AFM revealed that the hyphal tip surface has moderate roughness.