Hye Seon Song

Phylogenetic analysis of microalgae based on highly abundant proteins using mass spectrometry

The blooms of toxic phototrophic microorganisms, such as microalgae and cyanobacteria, which are typically found in freshwater and marine environments, are becoming more frequent and problematic in aquatic systems. Due to accumulation of toxic algae, harmful algal blooms (HABs) exert negative effects on aquatic systems. Therefore, rapid detection of harmful microalgae is important for monitoring the occurrence of HABs. Mass spectrometry-based methods have become sensitive, specific techniques for the identification and characterization of microorganisms. Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry (MS) allows us to measure a unique molecular fingerprint of highly abundant proteins in a microorganism and has been used for the rapid, accurate identification of bacteria and fungi in clinical microbiology. Here, we tested the specificity of MALDI-TOF MS using microalgal strains (Heterocapsa, Alexandrium, Nannochloropsis, Chaetoceros, Chlorella, and Dunaliella spp.). Our research suggested that this method was comparable in terms of the rapid identification of microalgea to conventional methods based on genetic information and morphology. Thus, this efficient mass spectrometry-based technique may have applications in the rapid identification of harmful microorganisms from aquatic environmental samples.

Halolamina sediminis sp. nov., an extremely halophilic archaeon isolated from solar salt

An extremely halophilic archaeal strain, halo-7T, was isolated from brine sediment of the Gomso solar saltern, Republic of Korea. Cells of strain halo-7T were pleomorphic, stained Gram-negative, lysed in distilled water and formed red-pigmented colonies. Strain halo-7T grew in the range of 25-45°C (optimum 37-40°C), pH 6.5-9.5 (optimum pH 7.0-8.0), 15-30% (w/v) NaCl (optimum, 20-25%), and 0.05-0.5 M MgCl2 (optimum 0.1-0.3 M). The minimal NaCl concentration to prevent cell lysis of strain halo-7T was 10% (w/v). The major polar lipids of the isolate were phosphatidylglycerol, phosphatidylglycerolphosphate methyl ester, an unidentified phospholipid, an unidentified lipid, and two unidentified glycolipids. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain halo-7T is closely related to the members of the genus Halolamina, Halolamina salina WSY15-H3T (98.7% 16S rRNA gene sequence similarity), Halolamina pelagica TBN21T (98.2%) and Halolamina rubra CBA1107T (97.4%). The genomic DNA G+C content determined for strain halo-7T (68.0 mol%) was slightly higher than those of H. salina JCM 18549T and H. rubra CBA1107T. DNA-DNA hybridization values between strain halo-7T and reference strains were < 25%. Based on phenotypic, chemotaxonomic and phylogenetic properties, we describe a novel species of the genus Halolamina, represented by strain halo-7T, for which we propose the name Halolamina sediminis sp. nov. The type strain is halo-7T ( = JCM 30187T = CECT 8739T).

Occurrence of viable, red-pigmented haloarchaea in the plumage of captive flamingoes

Flamingoes (Phoenicopterus spp.) whose plumage displays elegant colors, inhabit warm regions close to the ocean throughout the world. The pink or reddish color of their plumage originates from carotenoids ingested from carotenoid-abundant food sources, since flamingoes are unable to synthesize these compounds de novo. In this study, viable red-colored archaeal strains classified as extremely halophilic archaea (i.e., haloarchaea) and belonging to the genera Halococcus and Halogeometricum were isolated from the plumage of flamingoes in captivity. Detailed analysis for haloarchaeal community structure in flamingo feathers based on metagenomic data identified several haloarchaeal genera and unclassified sequences of the class Halobacteria at the genus level. Carotenoid pigment analyses showed that a bacterioruberin precursor carotenoid in haloarchaea was identical to one of the pigments found in flamingo plumage. To the best of our knowledge, this is the first report of viable extremophilic archaea in avian plumage, thus contributing to our understanding of the ecology of haloarchaea. The potential influence of haloarchaea as an environmental factor determining avian plumage coloration should be investigated in further studies.

Aquimarina versatilis sp. nov., isolated from seashore sand, and emended description of the genus Aquimarina

Strain CBA3207T, a novel Gram-stain-negative, aerobic and rod-shaped bacterium, was isolated from the seashore sand of Jeju island in South Korea. Strain CBA3207T grew optimally at 25-30 °C and pH 7.0-7.5 with 3.0-4.0 % (w/v) NaCl. It was catalase-positive, oxidase-negative, and hydrolysed starch, gelatin, and Tweens 20, 40 and 80. The 16S rRNA gene sequence of strain CBA3207T showed 96.0, 95.6, 95.6, 95.5 and 95.5 % similarity to that of Aquimarinamytili PSC33T, Aquimarinaagarivorans HQM9T, Aquimarinalatercula DSM 2041T, Aquimarinaintermedia KMM 6258T and Aquimarinaamphilecti 92VT, respectively. The major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G and summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1ω9c). The major respiratory quinone was menaquinone-6, and the major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and six unidentified lipids. The G+C content of the genomic DNA was 38.8 mol%. Based on phenotypic, genotypic and phylogenetic analyses, strain CBA3207T represents a novel species in the genus Aquimarina, for which the name Aquimarinaversatilissp. nov. is proposed. The type strain is CBA3207T (=KACC 17666T=JCM 19528T).

Complete genome sequence of Haloarcula sp. CBA1115 isolated from non-purified solar salts

Haloarcula sp. CBA1115, isolated from non-purified solar salts from South Korea, is a halophilic archaeon belonging to the family Halobacteriaceae. Here, we present the complete genome sequence of the strain Haloarcula sp. CBA1115 (4,225,046bp, with a G+C content of 61.98%), which is distributed over one chromosome and five plasmids. A comparison of the genome sequence of Haloarcula sp. CBA1115 with those of members of its closely related taxa showed that the closest neighbor is Haloarcula hispanica Y27, a popular model organism for archaeal studies. The strain was found to possess a number of genes predicted to be involved in osmo-regulatory strategies and metal regulation, suggesting that it might be useful for bioremediation in extreme environments.

Vulcanisaeta thermophila sp. nov., a hyperthermophilic and acidophilic crenarchaeon isolated from solfataric soil.

An anaerobic, rod-shaped, hyperthermophilic and acidophilic crenarchaeon, designated strain CBA1501(T), was isolated from solfataric soil of the Mayon volcano in the Republic of the Philippines. Phylogenetic analysis showed that strain CBA1501(T) is affiliated with the genus Vulcanisaeta in the phylum Crenarchaeota. DNA sequence similarities between the 16S rRNA gene of strain CBA1501(T) and those of Vulcanisaeta distributa IC-017(T) and Vulcanisaeta souniana IC-059(T) were 98.5 and 97.4 %, respectively. Strain CBA1501(T) grew between 75-90 °C, over a pH range of 4.0-6.0 and in the presence of 0-1.0 % (w/v) NaCl, with optimal growth occurring at 85 °C, pH 5.0, and with 0 % (w/v) NaCl. Fumarate, malate, oxidized glutathione, sulfur and thiosulfate were used as final electron acceptors, but FeCl3, nitrate and sulfate were not. The DNA G+C content of strain CBA1501(T) was 43.1 mol%. On the basis of polyphasic taxonomic analysis, strain CBA1501(T) represents a novel species of the genus Vulcanisaeta in the phylum Crenarchaeota, for which we propose the name Vulcanisaeta thermophila sp. nov. The type strain is CBA1501(T) ( = ATCC BAA-2415(T) = JCM 17228(T)).

Maribacter pelagius sp. nov., isolated from seawater

A Gram-stain-negative, gliding, non-endospore-forming and slightly halophilic bacterial strain, CBA3204T, was isolated from seawater and characterized by polyphasic taxonomic analysis. Phylogenetic analysis based on 16S rRNA sequences revealed that strain CBA3204T formed a distinct lineage within the family Flavobacteriaceae. The 16S rRNA sequences of strain CBA3204T had a sequence similarity level of 96.96 % to Maribacter arcticus KOPRI 20941T as the nearest phylogenetic neighbour. The strain grew optimally at 25-30 °C and in the presence of 2-4 % (w/v) NaCl. The dominant menaquinone was MK-6 and the major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. The DNA G+C content was 35.1 mol%. There were some differences in phenotypic properties among strain CBA3204T and other Maribacter species. On the basis of polyphasic analysis containing phenotypic, phylogenetic and chemotaxonomic data, strain CBA3204T (=KACC 17671T=JCM 19533T) is proposed as a novel species Maribacter pelagius sp. nov.

Genomic Analysis of a Pathogenic Bacterium, Paeniclostridium sordellii CBA7122 Containing the Highest Number of rRNA Operons, Isolated from a Human Stool Sample

Citation: Kim JY, Kim YB, Song HS, Chung W-H, Lee C, Ahn SW, Lee SH, Jung MY, Kim T-W, Nam Y-D and Roh SW (2017) Genomic Analysis of a Pathogenic Bacterium, Paeniclostridium sordellii CBA7122 Containing the Highest Number of rRNA Operons, Isolated from a Human Stool Sample. Front. Pharmacol. 8:840. doi: 10.3389/fphar.2017.00840 Genomic Analysis of a Pathogenic Bacterium, Paeniclostridium sordellii CBA7122 Containing the Highest Number of rRNA Operons, Isolated from a Human Stool Sample

Draft genome sequence of Halorubrum halophilum B8T, an extremely halophilic archaeon isolated from salt-fermented seafood

The extremely halophilic archaeon, Halorubrum halophilum B8(T) (=JCM 18963(T), CECT 8278(T)) was isolated from salt-fermented seafood. We report here the draft genome of H. halophilum B8(T), containing 3,677,984bp with a G+C content of 65.1%. The genome consists of 19 genes predicted to encode esterases.

Croceitalea litorea sp. nov., isolated from seashore sand.

Strain CBA3205T is a Gram-stain-negative, non-motile and rod-shaped bacterium that was isolated from the seashore sand of Jeju Island in South Korea. Based on the phylogenetic analysis, the most closed related species was Croceitalea eckloniae DOKDO 025T, with 94.8 % sequence similarity for the 16S rRNA gene. Strain CBA3205T was observed to grow optimally at 25-30 °C and at pH 8.5 in the presence of 2-3 % (w/v) NaCl. The major fatty acids of strain CBA3205T were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The major respiratory quinone was MK-6 and the major polar lipids were two unidentified amino-group-containing phospholipids and an unidentified polar lipid. The G+C content of the genomic DNA of strain CBA3205T was 62.5 mol%. Based on the phenotypic, genotypic and phylogenetic analyses, strain CBA3205T was considered to be a novel species belonging to the genus Croceitalea within the family Flavobacteriaceae, for which the name Croceitalea litorea sp. nov. is proposed. The type strain is CBA3205T ( = KACC 17669T = JCM 19531T).