So-Jung Kang

Exceptional Production of both Prodigiosin and Cycloprodigiosin as Major Metabolic Constituents by a Novel Marine Bacterium, Zooshikella rubidus S1-1

ABSTRACT A Gram-negative, red-pigment-producing marine bacterial strain, designated S1-1, was isolated from the tidal flat sediment of the Yellow Sea, Korea. On the basis of phenotypic, phylogenetic, and genetic data, strain S1-1 (KCTC 11448BP) represented a new species of the genus Zooshikella. Thus, we propose the name Zooshikella rubidus sp. nov. Liquid chromatography and mass spectrometry of the red pigments produced by strain S1-1 revealed that the major metabolic compounds were prodigiosin and cycloprodigiosin. In addition, this organism produced six minor prodigiosin analogues, including two new structures that were previously unknown. To our knowledge, this is the first description of a microorganism that simultaneously produces prodigiosin and cycloprodigiosin as two major metabolites. Both prodigiosin and cycloprodigiosin showed antimicrobial activity against several microbial species. These bacteria were approximately 1.5-fold more sensitive to cycloprodigiosin than to prodigiosin. The metabolites also showed anticancer activity against human melanoma cells, which showed significantly more sensitivity to prodigiosin than to cycloprodigiosin. The secondary metabolite profiles of strain S1-1 and two reference bacterial strains were compared by liquid chromatography-mass spectrometry. Multivariate statistical analyses based on secondary metabolite profiles by liquid chromatography-mass spectrometry indicated that the metabolite profile of strain S1-1 could clearly be distinguished from those of two phylogenetically related, prodigiosin-producing bacterial strains.

Roseovarius halocynthiae sp. nov., isolated from the sea squirt Halocynthia roretzi

A Gram-negative, non-motile, rod-shaped bacterial strain, designated MA1-6T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and was characterized to determine its taxonomic position. Strain MA1-6T grew optimally at pH 7.0-8.0, at 30 °C and in the presence of 2-3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MA1-6T fell within the clade comprising Ruegeria species and exhibited 95.3-96.5 % similarity to the type strains of recognized Ruegeria species. Strain MA1-6T contained Q-10 as the predominant ubiquinone and C18:1ω7c as the major fatty acid, which is consistent with data for Ruegeria species. The major polar lipids detected in strain MA1-6T and Ruegeria atlantica KCTC 12424T were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and an unidentified lipid. The DNA G+C content of strain MA1-6T was 58.6 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain MA1-6T can be distinguished from recognized Ruegeria species. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MA1-6T is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria halocynthiae sp. nov. is proposed; the type strain is MA1-6T (=KCTC 23463T=CCUG 60744T).

Roseovarius aestuarii sp. nov., isolated from a tidal flat of the Yellow Sea in Korea

A Gram-negative, motile, ovoid to rod-shaped bacterial strain, designated strain SMK-122T, was isolated from a Yellow Sea tidal flat located on the coast of Korea. Strain SMK-122T grew optimally at pH 7.0-8.0 and 30 degrees C. It contained Q-10 as the predominant ubiquinone and possessed C18 : 1omega7c and C16 : 0 as the major fatty acids. The DNA G+C content was 58.6 mol%. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain SMK-122T fell within the genus Roseovarius, being closest to Roseovarius nubinhibens ISM(T); the sequence similarities with respect to Roseovarius species ranged from 94.9 to 97.3 %. The mean value for DNA-DNA relatedness between strain SMK-122T and Rva. nubinhibens DSM 15170T was 13 %. Differential phenotypic properties of SMK-122T, together with its phylogenetic and genetic distinctiveness, revealed that this strain is distinct from recognized Roseovarius species. On this basis, strain SMK-122T represents a novel species of the genus Roseovarius, for which the name Roseovarius aestuarii sp. nov. is proposed. The type strain is SMK-122T (=KCTC 22174T =CCUG 55325T).

Hydrogenophaga bisanensis sp. nov., isolated from wastewater of a textile dye works

A Gram-negative, non-spore-forming, rod-shaped, Hydrogenophaga-like bacterial strain, K102(T), was isolated from wastewater collected from a textile dye works in Korea and subjected to a polyphasic taxonomic study. Strain K102(T) grew optimally at pH 7.0-8.0 and 30-37 degrees C in the presence of 0.5 % (w/v) NaCl. It contained Q-8 as the predominant ubiquinone and C(16 : 0), C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH and C(18 : 1)omega7c as the major fatty acids. The DNA G+C content was 64.8 mol%. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain K102(T) fell within the radiation of the cluster comprising species of the genus Hydrogenophaga. Strain K102(T) exhibited 16S rRNA gene sequence similarity values of 95.9-98.9 % to the type strains of recognized Hydrogenophaga species. Levels of DNA-DNA relatedness between strain K102(T) and the type strains of its four phylogenetically most closely related species, together with differential phenotypic properties, revealed that strain K102(T) could be distinguished from all recognized species of the genus Hydrogenophaga. On the basis of phenotypic, phylogenetic and genetic data, strain K102(T) is considered to represent a novel species of the genus Hydrogenophaga, for which the name Hydrogenophaga bisanensis sp. nov. is proposed. The type strain is K102(T) (=KCTC 12980(T) =CCUG 54518(T)).

Mucilaginibacter boryungensis sp. nov., isolated from soil

A Gram-stain-negative, non-motile, non-spore-forming bacterial strain, BDR-9(T), was isolated from soil collected from Boryung on the west coast of the Korean peninsula, and its taxonomic position was investigated by using a polyphasic study. Strain BDR-9(T) grew optimally at 25 °C, at pH 6.0-7.5 and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain BDR-9(T) fell within the clade comprising species of the genus Mucilaginibacter within the phylum Bacteroidetes. 16S rRNA gene sequence similarity values between strain BDR-9(T) and the type strains of species of the genus Mucilaginibacter were in the range 94.0-95.6 %. Strain BDR-9(T) contained MK-7 as the predominant menaquinone and iso-C(15 : 0) and C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH as the major fatty acids. The DNA G+C content was 44.3 mol%. Differential phenotypic properties and phylogenetic distinctiveness of strain BDR-9(T) demonstrated that this strain is distinguishable from species of the genus Mucilaginibacter. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain BDR-9(T) is considered to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter boryungensis sp. nov. is proposed. The type strain is BDR-9(T) ( = KCTC 23157(T)  = CCUG 59599(T)).

Seohaeicola saemankumensis gen. nov., sp. nov., isolated from a tidal flat.

A Gram-negative, non-motile and rod-, oval- or coccoid-shaped bacterial strain, SD-15(T), was isolated from a tidal flat of the Yellow Sea, Korea. The novel strain, which was phylogenetically closely related to the genera Phaeobacter, Leisingera and Marinovum, was studied using a polyphasic taxonomic approach. Strain SD-15(T) grew optimally at pH 7.0-8.0 and 30 degrees C in the presence of 2 % (w/v) NaCl. It contained Q-10 as the predominant ubiquinone and C(18 : 1)omega7c and 11-methyl C(18 : 1)omega7c as the major fatty acids. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and an unidentified lipid. The DNA G+C content was 63.4 mol%. Strain SD-15(T) exhibited the highest 16S rRNA gene sequence similarity values (95.1-96.4 %) to the type strains of species of the genus Phaeobacter, Leisingera methylohalidivorans MB2(T) and Marinovum algicola ATCC 51440(T). Strain SD-15(T) could be differentiated from members of the genera Phaeobacter, Leisingera and Marinovum by differences in the contents of some fatty acids, by the absence of aminolipid and by differences in some phenotypic properties. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain SD-15(T) represents a new genus and novel species, for which the name Seohaeicola saemankumensis gen. nov., sp. nov. is proposed. The type strain of the type species is Seohaeicola saemankumensis SD-15(T) (=KCTC 22175(T)=CCUG 55328(T)).

Mucilaginibacter litoreus sp. nov., isolated from marine sand

A Gram-staining-negative, non-spore-forming, facultatively anaerobic, non-flagellated, non-gliding, rod-shaped bacterium, designated strain BR-18(T), was isolated from marine sand collected on the western coast of South Korea. The taxonomic position of the novel strain was determined using a polyphasic approach. Strain BR-18(T) grew optimally at 25 °C, at pH 6.5-7.0 and in the absence of NaCl. In phylogenetic analyses based on 16S rRNA gene sequences, the novel strain fell within a clade comprising members of the genus Mucilaginibacter and appeared most closely related to Mucilaginibacter lutimaris BR-3(T) (96.6 % sequence similarity) and Mucilaginibacter rigui WPCB133(T) (95.9 %). The novel strain showed lower levels of 16S rRNA gene sequence similarity with the type strains of other members of the genus Mucilaginibacter (93.4-95.5 %) and those of other species included in the phylogenetic analyses (<91.6 %). Strain BR-18(T) contained MK-7 as its predominant menaquinone, summed feature 3 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH) and iso-C(15 : 0) as its major fatty acids, phosphatidylethanolamine and an unidentified aminophospholipid as its major polar lipids, and sphingolipids. The genomic DNA G+C content of the novel strain was 42.4 mol%. Based on the phylogenetic and phenotypic data, strain BR-18(T) represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter litoreus sp. nov. is proposed. The type strain is BR-18(T) ( = KCTC 23697(T)  = CCUG 61484(T)).

Mucilaginibacter lutimaris sp. nov., isolated from a tidal flat sediment

A Gram-staining-negative, non-spore-forming, facultatively aerobic, non-motile, rod-shaped bacterial strain, BR-3(T), was isolated from a tidal flat on the western coast of Korea, and subjected to a polyphasic study. Strain BR-3(T) grew optimally at 25 °C, at pH 6.5-7.0 and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain BR-3(T) fell within the clade comprising species of the genus Mucilaginibacter, joining the type strain of Mucilaginibacter rigui, with which it exhibited highest 16S rRNA gene sequence similarity (98.2%). 16S rRNA gene sequence similarity values between strain BR-3(T) and the type strains of the other species of the genus Mucilaginibacter were in the range 93.8-95.9%. A mean DNA-DNA relatedness value between strain BR-3(T) and M. rigui KCTC 12534(T) was 21%. Strain BR-3(T) contained MK-7 as the predominant menaquinone and C(16:1)ω7c and/or iso-C(15:0) 2-OH and iso-C(15:0) as the major fatty acids. The major polar lipids were phosphatidylethanolamine and an unidentified aminophospholipid. The DNA G+C content was 49.8 mol%. Differential phenotypic properties and phylogenetic and genetic distinctiveness of strain BR-3(T) demonstrated that this strain is separate from M. rigui as well as the other species of the genus Mucilaginibacter. On the basis of the data presented, strain BR-3(T) is considered to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter lutimaris sp. nov. is proposed. The type strain is BR-3(T) (=KCTC 23461(T) =CCUG 60742(T)).

Ohtaekwangia koreensis gen. nov., sp. nov. and Ohtaekwangia kribbensis sp. nov., isolated from marine sand, deep-branching members of the phylum Bacteroidetes

Two Gram-stain-negative, non-motile, non-spore-forming, rod-shaped bacterial strains, designated 3B-2(T) and 10AO(T), were isolated from a sand sample collected from the west coast of the Korean peninsula by using low-nutrient media, and their taxonomic positions were investigated in a polyphasic study. The strains did not grow on marine agar. They grew optimally at 30 °C and pH 6.5-7.5. Strains 3B-2(T) and 10AO(T) shared 97.5 % 16S rRNA gene sequence similarity and mean level of DNA-DNA relatedness of 12 %. In phylogenetic trees based on 16S rRNA gene sequences, strains 3B-2(T) and 10AO(T), together with several uncultured bacterial clones, formed independent lineages within the evolutionary radiation encompassed by the phylum Bacteroidetes. Strains 3B-2(T) and 10AO(T) contained MK-7 as the predominant menaquinone and iso-C(15 : 0) and C(16 : 1)ω5c as the major fatty acids. The DNA G+C contents of strains 3B-2(T) and 10AO(T) were 42.8 and 44.6 mol%, respectively. Strains 3B-2(T) and 10AO(T) exhibited very low levels of 16S rRNA gene sequence similarity (<85.0 %) to the type strains of recognized bacterial species. These data were sufficient to support the proposal that the novel strains should be differentiated from previously known genera of the phylum Bacteroidetes. On the basis of the data presented, we suggest that strains 3B-2(T) and 10AO(T) represent two distinct novel species of a new genus, for which the names Ohtaekwangia koreensis gen. nov., sp. nov. (the type species; type strain 3B-2(T)  = KCTC 23018(T)  = CCUG 58939(T)) and Ohtaekwangia kribbensis sp. nov. (type strain 10AO(T)  = KCTC 23019(T)  = CCUG 58938(T)) are proposed.

Gaetbulicola byunsanensis gen. nov., sp. nov., isolated from tidal flat sediment

A Gram-negative, non-motile and pleomorphic bacterial strain, SMK-114(T), which belongs to the class Alphaproteobacteria, was isolated from a tidal flat sample collected in Byunsan, Korea. Strain SMK-114(T) grew optimally at pH 7.0-8.0 and 25-30 degrees C and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain SMK-114(T) formed a cluster with Octadecabacter species, with which it exhibited 16S rRNA gene sequence similarity values of 95.2-95.4 %. This cluster was part of the clade comprising Thalassobius species with a bootstrap resampling value of 76.3 %. Strain SMK-114(T) exhibited 16S rRNA gene sequence similarity values of 95.1-96.3 % to members of the genus Thalassobius. It contained Q-10 as the predominant ubiquinone and C(18 : 1)omega7c as the major fatty acid. The DNA G+C content was 60.0 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain SMK-114(T) is considered to represent a novel species in a new genus for which the name Gaetbulicola byunsanensis gen. nov., sp. nov. is proposed. The type strain of Gaetbulicola byunsanensis is SMK-114(T) (=KCTC 22632(T) =CCUG 57612(T)).