Eun Sun Joo

Complete genome sequence of Deinococcus swuensis, a bacterium resistant to radiation toxicity

Deinococcus swuensis DY59T is a Grampositive, coccus-shaped bacterium. Most members of the genus Deinococcus are able to grow in the presence of high levels of chronic radiation toxicity and desiccation because they can protect enzymes from reactive oxygen species generated during ionizing radiation. The mechanisms behind the resistance to radiation toxicity and the genomic features of resistance could be useful to exploit Deinococcus swuensis in the biotechnological applications such as detoxification of xenobiotic contaminated with radioactive wastes. Strain DY59T showed resistance to gamma radiation with a D10 value (i.e. the dose required to reduce the bacterial population by 10-fold) in excess of 5 kGy. However, the genus Deinococcus is slightly characterized at the genome level, despite its potential importance. Thus, the present study determined the features of Deinococcus swuensis DY59T, as well as its genome sequence and annotation. The genome comprised of 3,531,443 bp with a G + C content of 67.4%, which included 3,305 protein-coding genes and 58 RNA genes. Based on the genome annotation, the strain DY59T undergoes prokaryotic type nucleotide excision repair pathway, restores the damaged gene, and resists the ionizing radiation toxicity.

Complete genome sequence of Rufibacter sp. DG31D, a bacterium resistant to gamma and UV radiation toxicity

The ionizing radiation toxicity becomes a major concern for the modern world, recent years, several special interest has been given to the research for the radiation resistant and the mechanisms of which the radiation resistant bacteria survive after the irradiation. In the current study, we have isolated strain DG31D was isolated from gamma ray-irradiated soil sample and showed resistant to gamma and UV radiation. The aim of this study is to understanding the radiation resistant mechanisms and their genomic features of the strain DG31D, which can be potentially used for the biotechnological application to degrade harmful soil contamination near the nuclear power stations and other radiation-affected areas. Strain DG31D showed resistant to UV and gamma radiation with D10 value of 10 kGy. The genome comprised of 4,820,793 bp with the G+C content of 51.4%. It contains the genomic features of enzymes involved in the nucleotide excision repair (NER) pathway that protect the damaged DNA.

Spirosoma swuense sp. nov., isolated from wet soil

Strain JBM2-3T, a pale-yellow-coloured, aerobic, catalase-negative, oxidase-positive and Gram-stain-negative bacterium, was isolated from wet soil. The isolate grew aerobically at 25-30 °C (optimum 25 °C), pH 6.0-8.0 (optimum pH 7.0) and in the presence of 0-0.5 % (w/v) NaCl (optimum 0 % NaCl). Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain JBM2-3T belonged to the genus Spirosoma, with a sequence similarity of 96.2 % with Spirosoma panaciterrae Gsoil 1519T. The strain showed the typical chemotaxonomic characteristics of the genus Spirosoma, with the presence of menaquinone 7 as the respiratory quinone; the major fatty acids were summed feature 3 (composed of C16: 1ω6c/ω7c), C16: 1ω5c and iso-C15: 0. The DNA G+C content of strain JBM2-3T was 47.4 mol%. The polar lipid profile contained major amounts of phosphatidylethanolamine and aminophospholipids. On the basis of its phenotypic and genotypic properties, and phylogenetic distinctiveness, strain JBM2-3T should be classified as a representative of a novel species in the genus Spirosoma, for which the name Spirosoma swuense sp. nov. is proposed. The type strain is JBM2-3T (=KCTC 52176T=JCM 31298T).

Spirosoma pulveris sp. nov., a bacterium isolated from a dust sample collected at Chungnam province, South Korea

Strain JSH 5-14T, a Gram-negative, non-motile, and curved rod-shaped bacterium, was isolated from a dust sample collected at Nonsan, Chungnam province, South Korea, and was characterized to determine its taxonomic position. Phylogenetic analysis based on the 16S rRNA gene sequence of strain JSH 5-14T revealed that it belongs to the genus Spirosoma, family Cytophagaceae, class Cytophagia. The highest degree of sequence similarities of strain JSH 5-14T were found with Spirosoma liguale DSM 74T (97.8%) and Spirosoma endophyticum EX 36T (96.2%). The predominant fatty acids were summed feature 3 (composed of C16:1ω7c/C16:1ω6c) and C16:1ω5c. The major polar lipid was phosphatidylethanolamine, and the predominant respiratory quinone was MK-7. Based on the phylogenetic, chemotaxonomic, and phenotypic data, we propose the strain JSH 5-14T (=KCTC 42550T =JCM 30688T =KEMB 9004-165T) should be classified as a type strain of a novel species, for which the name Spirosoma pulveris sp. nov., is proposed.

Spirosoma montaniterrae sp. nov., an ultraviolet and gamma radiation-resistant bacterium isolated from mountain soil §

A Gram-negative, yellow-pigmented, long-rod shaped bacterial strain designated DY10T was isolated from a soil sample collected at Mt. Deogyusan, Jeonbuk province, South Korea. Optimum growth observed at 30°C and pH 7. No growth was observed above 1% (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain DY10T belonged to the genus Spirosoma and was distantly related to Spirosoma arcticum R2–35T (91.0%), Spirosoma lingual DSM 74T (90.8%), Spirosoma endophyticum EX36T (90.7%), Spirosoma panaciterrae DSM 21099T (90.5%), Spirosoma rigui WPCB118T (90.2%), Spirosoma spitsbergense DSM 19989T (89.8%), Spirosoma luteum DSM 19990T (89.6%), Spirosoma oryzae RHs22T (89.6%), and Spirosoma radiotolerans DG5AT (89.1%). Strain DY10T showed resistance to gamma and ultraviolet radiation. The chemotaxonomic characteristics of strain DY10T were consistent with those of the genus Spirosoma, with the quinone system with MK-7 as the predominant menaquinone, iso-C15:0, C16:1ω5c, and summed feature3 (C16:1ω7c/C16:1ω6c), and phosphatidylethanolamine as the major polar lipid. The G+C content of the genomic DNA was 53.0 mol%. Differential phenotypic properties with the closely related type strains clearly distinguished strain DY10T from previously described members of the genus Spirosoma and represents a novel species in this genus, for which the name Spirosoma montaniterrae sp. nov. is proposed. The type strain is DY10T (=KCTC 23999T =KEMB 9004–162T =JCM 18492T).

Complete genome sequence of Hymenobacter sp. DG25B, a novel bacterium with gamma-radiation resistance isolated from soil in South Korea

A Gram-negative, rod-shaped, non-motile, gamma and UV radiation resistant bacterium Hymenobacter radioresistens DG25B was isolated from a soil sample collected in South Korea. The complete genome sequence of H. radioresistens DG25B consists of one circular chromosome (3,874,646 bp). The bacterium was isolated from gamma ray irradiated soil and contains the genomic features of enzymes involved in the nucleotide excision repair (NER) pathway that protect the damaged DNA. The genome also contains other genes involved in the efficient removal of double-strand breaks (DSB) caused by the ionizing radiations.

Deinococcus actinosclerus sp. nov., a novel bacterium isolated from soil, South Korea.

Three Gram-stain-positive, catalase- and oxidase-positive coccus- or rod-shaped bacterial strains, designated BM2T, BM4 and BM5, were isolated from soil in South Korea. They showed strong resistance to gamma radiation with a D10 value of 9 kGy but weak UVC resistance. The 16S rRNA sequences of strains BM2T, BM4 and BM5 represent a novel subline within the genus Deinococcus in the family Deinococcaceae. The 16S rRNA gene sequences of strains BM2T, BM4 and BM5 were indistinguishable and showed 98.1-87.3 % similarity with other species of the genus Deinococcus. Strain BM2T exhibited relatively high levels of DNA-DNA hybridization with BM4 (87 ± 0.8 %) and BM5 (92 ± 1.2 %). Meanwhile, it showed a low level of DNA-DNA hybridization ( < 30 %) with other closely related species of the genus Deinococcus. The strains showed the typical chemotaxonomic characteristics of the genus Deinococcus, with the presence of menaquinone 8 as the respiratory quinone; the major fatty acids were summed feature 3 (composed of C16 : 1ω7c/C16 : 1ω6c), C15 : 1ω6c and C16 : 0. The DNA G+C content of strain BM2T was 69.7 mol%. The polar lipid profile included major amounts of phosphatidylglycerol, phosphatidylcholine and an unknown aminolipid. On the basis of phenotypic and genotypic properties, and phylogenetic distinctiveness, strains BM2T, BM4 and BM5 should be classified in a novel species in the genus Deinococcus, for which the name Deinococcus actinosclerus sp. nov. is proposed. The type strain is BM2T ( = KEMB 5401-184T = JCM 30700T); reference strains are BM4 ( = JCM 30701) and BM5 ( = JCM 30702).

Flavisolibacter swuensis sp. nov. Isolated from Soil

A Gram-staining-negative, non-motile, non-spore-forming, and rod-shaped bacterium designated as strain SR2-4-2T was isolated from soil in South Korea. Phylogenetic analysis based on 16S rRNA gene sequence of strain SR2-4-2T revealed that it belonged to the genus of Flavisolibacter, family of Chitinophagaceae, and class of Sphingobacteriia. It shared sequence similarities with Flavisolibacter ginsengisoli Gsoil 643T (96.4%), Flavisolibacter ginsengiterrae Gsoil 492T (96.3%), and Flavisolibacter rigui 02SUJ3T (93.0%). Chemotaxonomic data revealed that its predominant fatty acids were iso-C15:0 (26.4%) and iso-C17:0 3OH (10.7%). Its major polar lipid was phosphatidylethanolamine (PE) and its predominant respiratory quinone was MK-7. The G+C content of genomic DNA of the strain SR2-4-2T DNA was 45.0%. Based on the phylogenetic, chemotaxonomic, and phenotypic data, the strain SR2-4-2T (=JCM 19974T =KEMB 9004–156T) is classified as a type strain of a novel species for which the name of Flavisolibacter swuensis sp. nov. is proposed.

Complete genome sequence of Deinococcus soli N5T, a gamma-radiation- resistant bacterium isolated from rice field in South Korea

A Gram-negative, non-motile and short-rod shaped and gamma-radiation-resistant bacterium Deinococcus soli N5(T), isolated from a rice field soil in South Korea. The complete genome of D. soli N5(T) consists of a chromosome (3,236,984bp). The key enzymes for the central DNA repair mechanisms were present in the genome. The enzyme coding genes has been identified which is involving in the nucleotide excision repair (NER) pathway. The gene cluster in the genome sequence suggest that the D. soli N5(T) use (NER) pathways for efficient removal of pyrimidine dimers that are the most abundant type of UV- induced damage.

Hymenobacter sedentarius sp. nov., isolated from a soil

A novel Gram-negative and red-pinkish bacterium designated DG5BT was isolated from a dry soil. Cells were rods that were catalase- and oxidase-positive, and non-motile. The strain was found to grow at temperatures from 10 to 30°C (optimum 25°C) and pH 6.0–8.0, (optimum pH 7) on R2A broth. 16S rRNA gene sequence (1,452 bp) analysis of this strain identified it as a member of the genus Hymenobacter that belongs to the class Cytophagia. The highest gene sequence similarities were with Hymenobacter arizonensis OR362-8T (98.3%), Hymenobacter humi DG31AT (97.6%), and Hymenobacter glaciei VUG-A130T (96.6%). Strain DG5BT exhibited <70% DNA-DNA relatedness with H. arizonensis (34.7 ± 7.0%; reciprocally, 29.7 ± 1.2%) and H. humi (39.4 ± 4.3%; reciprocally, 39.5 ± 3.3%) as a different genomic species, and its genomic DNA G+C content was 59.8%. Strain DG5BT had the following chemotaxonomic characteristics: the major fatty acids are iso-C15:0, anteiso-C15:0, C16:1ω5c, and summed feature 3 (C16:1ω7c / C16:1ω6c); polar lipid profile contained phosphatidylethanolamine (PE), unknown aminophospholipid (APL), unknown glycolipids (GL), unknown phospholipids (PL), and unknown polar lipids (L); the major quinone is MK-7. The absorbance peak of pigment is at 481.0 nm. Strain DG5BT showed low-level resistance to gamma-ray irradiation. Phenotypic, chemotaxonomic, and genotypic properties indicated that isolate DG5BT represents a novel species within the genus Hymenobacter for which the name Hymenobacter sedentarius sp. nov. is proposed. The type strain is DG5BT (=KCTC 32524T =JCM 19636T).