Error-Prone Replication through UV Lesions by DNA Polymerase θ Protects against Skin Cancers.

Cancers from sun-exposed skin accumulate "driver" mutations, causally implicated in oncogenesis. Because errors incorporated during translesion synthesis (TLS) opposite UV lesions would generate these mutations, TLS mechanisms are presumed to underlie cancer development. To address the role of TLS in skin cancer formation, we determined which DNA polymerase is responsible for generating UV mutations, analyzed the relative contributions of error-free TLS by Polη and error-prone TLS by Polθ to the replication of UV-damaged DNA and to genome stability, and examined the incidence of UV-induced skin cancers in Polθ-/-, Polη-/-, and Polθ-/- Polη-/- mice. Our findings that the incidence of skin cancers rises in Polθ-/- mice and is further exacerbated in Polθ-/- Polη-/- mice compared with Polη-/- mice support the conclusion that error-prone TLS by Polθ provides a safeguard against tumorigenesis and suggest that cancer formation can ensue in the absence of somatic point mutations.

WRN exonuclease imparts high fidelity on translesion synthesis by Y family DNA polymerases.

Purified translesion synthesis (TLS) DNA polymerases (Pols) replicate through DNA lesions with a low fidelity; however, TLS operates in a predominantly error-free manner in normal human cells. To explain this incongruity, here we determine whether Y family Pols, which play an eminent role in replication through a diversity of DNA lesions, are incorporated into a multiprotein ensemble and whether the intrinsically high error rate of the TLS Pol is ameliorated by the components in the ensemble. To this end, we provide evidence for an indispensable role of Werner syndrome protein (WRN) and WRN-interacting protein 1 (WRNIP1) in Rev1-dependent TLS by Y family Polη, Polι, or Polκ and show that WRN, WRNIP1, and Rev1 assemble together with Y family Pols in response to DNA damage. Importantly, we identify a crucial role of WRN's 3' → 5' exonuclease activity in imparting high fidelity on TLS by Y family Pols in human cells, as the Y family Pols that accomplish TLS in an error-free manner manifest high mutagenicity in the absence of WRN's exonuclease function. Thus, by enforcing high fidelity on TLS Pols, TLS mechanisms have been adapted to safeguard against genome instability and tumorigenesis.

Implications of inhibition of Rev1 interaction with Y family DNA polymerases for cisplatin chemotherapy.

Chemotherapy with cisplatin becomes limiting due to toxicity and secondary malignancies. In principle, therapeutics could be improved by targeting translesion synthesis (TLS) polymerases (Pols) that promote replication through intrastrand cross-links, the major cisplatin-induced DNA adduct. However, to specifically target malignancies with minimal adverse effects on normal cells, a good understanding of TLS mechanisms in normal versus cancer cells is paramount. We show that in normal cells, TLS through cisplatin intrastrand cross-links is promoted by Polη- or Polι-dependent pathways, both of which require Rev1 as a scaffolding component. In contrast, cancer cells require Rev1-Polζ. Our findings that a recently identified Rev1 inhibitor, JH-RE-06, purported to specifically disrupt Rev1 interaction with Polζ to block TLS through cisplatin adducts in cancer cells, abrogates Rev1's ability to function with Y family Pols as well, implying that by inactivating Rev1-dependent TLS in normal cells, this inhibitor will exacerbate the toxicity and tumorigenicity of chemotherapeutics with cisplatin.

DNA polymerase θ accomplishes translesion synthesis opposite 1,N6-ethenodeoxyadenosine with a remarkably high fidelity in human cells.

Here we show that translesion synthesis (TLS) opposite 1,N6-ethenodeoxyadenosine (εdA), which disrupts Watson-Crick base pairing, occurs via Polι/Polζ-, Rev1-, and Polθ-dependent pathways. The requirement of Polι/Polζ is consistent with the ability of Polι to incorporate nucleotide opposite εdA by Hoogsteen base pairing and of Polζ to extend synthesis. Rev1 polymerase and Polθ conduct TLS opposite εdA via alternative error-prone pathways. Strikingly, in contrast to extremely error-prone TLS opposite εdA by purified Polθ, it performs predominantly error-free TLS in human cells. Reconfiguration of the active site opposite εdA would provide Polθ the proficiency for error-free TLS in human cells.

Description of Roseibium sediminicola sp. nov. Isolated from Sediment of a Tidal Flat on the Yellow Sea Coast.

A Gram-stain-negative, aerobic, rod-shaped, motile, flagellated bacterial strain, designated as CAU 1639T, was isolated from the tidal flat sediment on the Yellow Sea in the Republic of Korea. Growth of the isolate was observed at 20-37 °C, at pH 5.0-10.5 and with 0-7% (w/v) NaCl. The genomic DNA G + C content was 60.8%. Phylogenetic analysis, grounded on 16S rRNA gene sequencing, revealed that strain CAU 1639T was closely related to species within the genus Roseibium. It shared the highest similarity with Roseibium album CECT 5095T, followed by Roseibium aggregatum IAM 12614T and Roseibium salinum Cs25T, with 16S rRNA gene sequence similarity ranging from 98.0-98.4%. It was observed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values ranged between 72.5-79.5 and 20.0-22.9%, respectively. The polyphasic taxonomic analysis reveals that strain CAU 1639T represents a novel species in the genus Roseibium with the proposed name Roseibium sediminicola sp. nov. The type strain is CAU 1639T (= KCTC 82430T = MCCC 1K06081T).

Description of Mycolicibacterium arenosum sp. nov. Isolated from Coastal Sand on the Yellow Sea Coast.

A Gram-staining-positive, aerobic, non-spore-forming bacterium was isolated from coastal sand samples from Incheon in the Republic of Korea and designated as strain CAU 1645T. The optimum conditions for growth were observed at 30 °C in growth media containing 1% (w/v) NaCl at pH 9.0. The predominant respiratory quinone was MK-9 and the major fatty acids were C16:0, C17:1 w7c, and summed feature 7. Similarly, the 16S rRNA gene sequence exhibited the highest similarity with Mycolicibacterium bacteremicum DSM 45578T and Mycolicibacterium neoaurum JCM 6365T, both of which exhibited similarity rates of 97.2%. The genomic DNA G+C content was 68.2%. The whole genome of strain CAU 1645T was obtained and annotated with annotation using RAST server. The pan-genome analysis was determined using Prokka, Roary, and Phandango. In the pan-genome analysis, the strain CAU 1645T shared 40 core genes with closely related Mycolicibacterium species, including the AcpM gene, the meromycolate extension acyl carrier protein involved in forming impermeable cell walls in mycobacteria. Therefore, our findings demonstrated that the isolate represents a novel species of the genus Mycolicibacterium, for which we propose the name Mycolicibacterium arenosum sp. nov. The type strain is CAU 1645T (= KCTC 49724T = MCCC 1K07087T).

Roseobacter insulae sp. nov. and Loktanella gaetbuli sp. nov., isolated from tidal flats in the Yellow Sea in Korea.

Two bacterial strains (designated as YSTF-M11T and TSTF-M6T) were isolated from tidal flat sediments of the Yellow Sea, Republic of Korea, and taxonomically characterized. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain YSTF-M11T clusters with the type strains of Roseobacter species and strain TSTF-M6T clusters with the type strains of Loktanella salsilacus, Loktanella fryxellensis and Loktanella atrilutea. Strains YSTF-M11T and TSTF-M6T exhibited 16S rRNA gene sequence similarity values of 97.5-98.9 % and 94.1-97.2 % to the type strains of four Roseobacter species and to the type strains of four Loktanella species, respectively. An UBCG tree based on genomic sequences and a tree based on AAI showed that strains YSTF-M11T and TSTF-M6T form a cluster with the type strains of Roseobacter species and with the type strains of L. salsilacus, L. fryxellensis and L. atrilutea, respectively. The ANI and dDDH values between genomic sequences of strain YSTF-M11T and the type strains of four Roseobacter species and between those of strain TSTF-M6T and the type strains of the three Loktanella species were in ranges of 74.0-75.9 and 18.2-19.7 % and 74.7-75.5 and 18.8-19.3 %, respectively. The DNA G+C contents of strains YSTF-M11T and TSTF-M6T were 60.3 and 61.9 % based on their genomic sequences. Both strains contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. Strains YSTF-M11T and TSTF-M6T were separated from recognized Roseobacter species and L. salsilacus, L. fryxellensis and L. atrilutea, respectively, by their phenotypic properties together with the phylogenetic and genetic distinctiveness. Based on data presented in this study, strains YSTF-M11T (=KACC 21642T =NBRC 115155T) and TSTF-M6T (=KACC 21643T =NBRC 115154T) are considered to represent novel species of the genera Roseobacter and Loktanella, respectively, for which the names Roseobacter insulae sp. nov. and Loktanella gaetbuli sp. nov. are proposed.

Tianweitania aestuarii sp. nov., isolated from a coastal dune, reclassification of Corticibacterium populi as Tianweitania populi comb. nov., and emended description of the genus Tianweitania.

A Gram-stain-negative, aerobic, non-flagellated and coccoid or ovoid bacterial strain, BSSL-BM11T, was isolated from sand of coastal dunes along the Yellow Sea of the Korean peninsula. Strain BSSL-BM11T grew optimally at 30 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences, the up-to-date bacterial core gene set and average amino acid identity (AAI) showed that strain BSSL-BM11T forms a cluster with the type strains of Tianweitania sediminis and Corticibacterium populi. Strain BSSL-BM11T showed 16S rRNA gene sequence similarities of 98.3 and 98.0 % to the type strains of T. sediminis and C. populi, respectively, and less than 96.4 % to the type strains of the other recognized species. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain BSSL-BM11T and the type strains of T. sediminis and C. populi were 77.0-84.8 % and 20.0-28.1 %, respectively. The 16S rRNA gene similarity, AAI, ANI and dDDH values between T. sediminis Z8T and C. populi KCTC 42249T were 98.0, 77.4, 76.7 and 20.1 %, respectively. The DNA G+C content of strain BSSL-BM11T from genomic sequence data was 61.3 mol%. Strain BSSL-BM11T contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c, C16 : 0 and cyclo C19 : 0 ω8c as the major fatty acids. The major polar lipids of strain BSSL-BM11T were phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine. Based on the polyphasic data, it is proposed that C, populi be reclassified as a member of the genus Tianweitania. Phenotypic and phylogenetic analyses revealed that strain BSSL-BM11T is separated from T. sediminis and C. populi. On the basis of the data presented here, strain BSSL-BM11T (=KACC 21634T=NBRC 114503T) is considered to represent a novel species of the genus Tianweitania, for which the name Tianweitania aestuarii sp. nov. is proposed.

Gracilimonas sediminicola sp. nov., a moderately halotolerant bacterium isolated from seaweed sediment collected in the East Sea, Republic of Korea.

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated as strain CAU 1638T, was isolated from seaweed sediment collected in the Republic of Korea. The cells of strain CAU 1638T grew at 25-37 °C (optimum, 30 °C), at pH 6.0-7.0 (optimum, pH 6.5) and in the presence of 0-10% NaCl (optimum, 2 %). The cells were positive for catalase and oxidase and did not hydrolyse starch and casein. Strain CAU 1638T was most closely related to Gracilimonas amylolytica KCTC 52885T (97.7 %), followed by Gracilimonas halophila KCTC 52042T (97.4 %), Gracilimonas rosea KCCM 90206T (97.2 %), Gracilimonas tropica KCCM 90063T and Gracilimonas mengyeensis DSM 21985T (97.1 %), as revealed by 16S rRNA gene sequencing. MK-7 was the major isoprenoid quinone, and iso-C15  : 0 and C15  : 1 ω6c were the major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, two unidentified lipids, two unidentified glycolipids and three unidentified phospholipids. The G+C content of the genome was 44.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain CAU 1638T and the reference strains were 73.1-73.9 % and 18.9-21.5  %, respectively. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CAU 1638T represents a novel species of the genus Gracilimonas, for which the name Gracilimonas sediminicola sp. nov. is proposed. The type strain is CAU 1638T (=KCTC 82454T=MCCC 1K06087T).

Rev1 promotes replication through UV lesions in conjunction with DNA polymerases η, ι, and κ but not DNA polymerase ζ.

Translesion synthesis (TLS) DNA polymerases (Pols) promote replication through DNA lesions; however, little is known about the protein factors that affect their function in human cells. In yeast, Rev1 plays a noncatalytic role as an indispensable component of Polζ, and Polζ together with Rev1 mediates a highly mutagenic mode of TLS. However, how Rev1 functions in TLS and mutagenesis in human cells has remained unclear. Here we determined the role of Rev1 in TLS opposite UV lesions in human and mouse fibroblasts and showed that Rev1 is indispensable for TLS mediated by Polη, Polι, and Polκ but is not required for TLS by Polζ. In contrast to its role in mutagenic TLS in yeast, Rev1 promotes predominantly error-free TLS opposite UV lesions in humans. The identification of Rev1 as an indispensable scaffolding component for Polη, Polι, and Polκ, which function in TLS in highly specialized ways opposite a diverse array of DNA lesions and act in a predominantly error-free manner, implicates a crucial role for Rev1 in the maintenance of genome stability in humans.

DNA polymerase λ promotes error-free replication through Watson-Crick impairing N1-methyl-deoxyadenosine adduct in conjunction with DNA polymerase ζ.

In a previous study, we showed that replication through the N1-methyl-deoxyadenosine (1-MeA) adduct in human cells is mediated via three different Polι/Polθ, Polη, and Polζ-dependent pathways. Based on biochemical studies with these Pols, in the Polι/Polθ pathway, we inferred a role for Polι in the insertion of a nucleotide (nt) opposite 1-MeA and of Polθ in extension of synthesis from the inserted nt; in the Polη pathway, we inferred that this Pol alone would replicate through 1-MeA; in the Polζ pathway, however, the Pol required for inserting an nt opposite 1-MeA had remained unidentified. In this study, we provide biochemical and genetic evidence for a role for Polλ in inserting the correct nt T opposite 1-MeA, from which Polζ would extend synthesis. The high proficiency of purified Polλ for inserting a T opposite 1-MeA implicates a role for Polλ-which normally uses W-C base pairing for DNA synthesis-in accommodating 1-MeA in a syn confirmation and forming a Hoogsteen base pair with T. The potential of Polλ to replicate through DNA lesions by Hoogsteen base pairing adds another novel aspect to Polλ's role in translesion synthesis in addition to its role as a scaffolding component of Polζ. We discuss how the action mechanisms of Polλ and Polζ could be restrained to inserting a T opposite 1-MeA and extending synthesis thereafter, respectively.

Devosia litorisediminis sp. nov., isolated from a sand dune.

A Gram-negative, aerobic, non-motile, and rod-shaped bacterial strain, designated BSSL-BM10T, was isolated from sand of a dune that was collected from the Yellow Sea, Republic of Korea. It was subjected to a polyphasic taxonomic study. 16S rRNA gene sequence analysis showed that strain BSSL-BM10T fell phylogenetically within the radiation comprising type strains of Devosia species. The 16S rRNA gene sequence of strain BSSL-BM10T shared sequence similarities of 98.2% with the type strain of D. naphthalenivorans and 93.5-97.7% with type strains of other Devosia species. ANI and dDDH values between strain BSSL-BM10T and type strains of 18 Devosia species were 71.0-78.4% and 18.8-21.5%, respectively. The DNA G + C content of strain BSSL-BM10T was 60.9% based on its genomic sequence data. Strain BSSL-BM10T contained Q-10 as the predominant ubiquinone and 11-methyl C18:1 ω7c, C18:1 ω7c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C16:0 as its major fatty acids. Major polar lipids of strain BSSL-BM10T were phosphatidylglycerol and two unidentified glycolipids. Strain BSSL-BM10T showed distinguishable phenotypic properties with its phylogenetic and genetic distinctiveness separated from recognized Devosia species. Based on data presented in this study, strain BSSL-BM10T should be placed in the genus Devosia. The name Devosia litorisediminis sp. nov. is proposed for strain BSSL-BM10T (= KACC 21633T = NBRC 115152T).

Mesonia aestuariivivens sp. nov., isolated from a tidal flat.

A Gram-negative, aerobic, non-flagellated and ovoid or rod-shaped bacterial strain (JHPTF-M18T), which was isolated from a tidal flat sediment in Republic of Korea, was taxonomically characterized. Strain JHPTF-M18T grew optimally at 25 °C, at pH 7.0-7.5 and in the presence of 2.0-3.0% (w/v) NaCl. 16S rRNA gene sequence analysis showed that strain JHPTF-M18T forms a phylogenetic lineage within the radiation comprising type strains of Mesonia species. The 16S rRNA gene of strain JHPTF-M18T shared sequence similarities of 97.7% with that of type strain of M. mobilis and 92.5-96.8% with those of type strains of the other nine Mesonia species. The DNA G+C content was 33.1% based on its genomic sequence. AAI, ANI and dDDH values between strain JHPTF-M18T and the type strains of M. mobilis, M. hitae, M. oceanica, M. phycicola and M. algae were 72.1-83.7%, 73.1-79.7% and 18.5-22.8%, respectively. Strain JHPTF-M18T contained MK-6 as the predominant menaquinone and iso-C15:0, iso-C17:0 3-OH and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) as its major fatty acids. Major polar lipids of strain JHPTF-M18T were phosphatidylethanolamine and two unidentified lipids. Strain JHPTF-M18T was separated from recognized Mesonia species by its phenotypic properties together with the phylogenetic and genetic distinctiveness. Based on data presented in this study, strain JHPTF-M18T is considered to represent a novel species of the genus Mesonia. The name Mesonia aestuariivivens sp. nov. is proposed for JHPTF-M18T (=KACC 22185T = NBRC 115119T).

Marinobacterium arenosum sp. nov., isolated from a coastal sand.

A Gram-negative, aerobic, motile, rod-shaped bacterium, designated strain CAU 1594T, was isolated from a coastal sand sample collected in the Republic of Korea. Cells of strain CAU 1594T grew best at 30 °C, pH 7.5, and in the presence of 1% (w/v) NaCl. Phylogenetic analysis, based on 16S rRNA gene sequencing, indicated that strain CAU 1594T was affiliated with the genus Marinobacterium and most similar to Marinobacterium jannaschii ATCC 27135T (95.1%) and Marinobacterium stanieri ATCC 27130T (94.9%). The whole genome of strain CAU 1594T was 4,917,683 bp, including 4,188 CDSs, with a 60.4 mol% G + C content. Based on draft genome sequences, the average nucleotide identity and digital DNA-DNA hybridization values of strain CAU 1594T were within the ranges of 71.9-73.1% and 20.0-2.1%, respectively, compared to reference strains. The major respiratory quinone was ubiquinone-8, and the major fatty acids were C16:0, summed feature 3 (C16:1 ω6c and C16:1 ω7c), and summed feature 8 (C18:1 ω6c and C18:1 ω7c). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Based on these results, strain CAU 1594T represents a novel species of the genus Marinobacterium, for which the name Marinobacterium arenosum sp. nov. is proposed. The type strain is CAU 1594T (=KCTC 82405T=MCCC 1K05672T).

Thalassococcus arenae sp. nov. isolated from sea sand.

A Gram-negative, aerobic, rod-shaped bacterium, designated strain CAU 1522T, was isolated from a sea sand sample collected from the Republic of Korea. Optimal growth of strain CAU 1522T ensued at 30 °C, pH 7.5, and 1.0% (w/v) NaCl. Strain CAU 1522T was affiliated to the genus Thalassococcus with high similarity to T. lentus KCTC 32084T (97.5%), T. profundi MCCC 1K03253T (96.5%), and T. halodurans JCM 13833T (96.1%) according to phylogenetic analysis based on 16S rRNA gene sequences. The whole genome of strain CAU 1522T was 3.7 Mb in length and included 7 contigs and 3599 protein-coding genes, with a G + C content of 65.4 mol%. The predominant cellular fatty acids were C18:1 ω6c and/or C18:1 ω7c (summed feature 8), with Q-10 being the sole isoprenoid quinone. The polar lipids included phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphoglycolipid, and an unidentified lipid. These phenotypic, chemotaxonomic, and phylogenetic data support that strain CAU 1522T is a novel Thalassococcus species, for which the name T. arenae sp. nov. is proposed. The type strain is CAU 1522T (= KCTC 72545T = MCCC 1K04064T).

Paenibacillus arenosi sp. nov., a siderophore-producing bacterium isolated from coastal sediment.

In this study, strain CAU 1523T, a novel Gram-positive-positive bacterium isolated from marine sediment collected from the coast of Busan, Republic of Korea, was characterized using a polyphasic taxonomic approach. This strain showed growth at a temperature range of 20-37 °C (optimum, 30 °C), a pH range of 6.5-9.5 (optimum, 7.5), and in the presence of 0-3% (w/v) NaCl (optimum, 1%). Phylogenetic analysis based on 16S rRNA gene sequencing and 92 concatenated core genes indicated that CAU 1523T belonged to the genus Paenibacillus, sharing the highest sequence similarity with P. assamensis JCM 13186T (98.0%). CAU 1523T was differentiated from other Paenibacillus species by average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values, using cut-off values of 95-96%, 90%, and 70%, respectively, for closely related strains. The genome of CAU 1523T possessed various biosynthetic gene clusters, one of which encoded a putative siderophore-interacting protein. Siderophore production by the isolate was confirmed using the qualitative chrome azurol sulfonate (CAS) agar assay. Based on its phylogenetic and physiological characteristics, strain CAU 1523T represents a novel, siderophore-producing species within the genus Paenibacillus, for which the name Paenibacillus arenosi sp. nov. is proposed, with the type strain CAU 1523T (= KCTC 43108T = MCCC 1K04063T).

Zhongshania aquimaris sp. nov., isolated from seawater.

A Gram-negative, motile, rod-shaped, aerobic bacterial strain CAU 1632T was isolated from a seawater sample collected in the Republic of Korea. The cells of strain CAU 1632T grew optimally at 30 °C and pH 7.0 in 0% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CAU 1632T formed a tight phyletic lineage with Zhongshania antarctica ZS-23T, Zhongshania borealis CL-AS9T, Zhongshania marina DSW25-10T, Zhongshania guokunii ZS6-22T, 'Zhongshania ponticola GM-8T', Zhongshania aliphaticivorans SM-2T and shared a high similarity between 97.2% and 97.7%. The whole genome of strain CAU 1632T was 4.3-Mb with 3,780 protein-coding genes, 12 contigs, and a DNA G+C content of 49.4 mol%. The major fatty acids of strain CAU 1632T were C17:1 ω8c, C19:1 ω6c and/or C19:0 cyclo ω10c (summed feature 3), and C18:1 ω6c and/or C18:1 ω7c (summed feature 8). Q-8 was the only respiratory quinone. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two aminophospholipids, and two phospholipids. Based on the results of phenotypic, chemotaxonomic, and phylogenetic analyses, strain CAU 1632T represents a novel species within the genus Zhongshania, for which the name Zhongshania aquimaris sp. nov. is proposed. The type strain is CAU 1632T (= KCTC 82432T = MCCC 1K06086T).

Marinobacter arenosus sp. nov., a halotolerant bacterium isolated from a tidal flat.

A Gram-negative, rod-shaped, motile bacterium, designated strain CAU 1620T, was isolated from a tidal flat sediment in Incheon, Republic of Korea. Strain CAU 1620T grew optimally at 30 °C and pH 8.0 in the presence of 6.0% (w/v) NaCl. The results of 16S rRNA gene sequence analysis revealed that strain CAU 1620T showed the highest similarity to Marinobacter adhaerens DSM 23420T (98.5%), followed by Marinobacter algicola DSM 16394T (98.3%) and Marinobacter maroccanus LMG 30465T (98.2%). The average nucleotide identity and digital DNA-DNA hybridisation values between strain CAU 1620T and related strains were estimated as 75.6-78.1% and 19.5-20.9%, respectively. The DNA G + C content based on the draft genome sequence was 59.2%, and the major respiratory quinone was ubiquinone-9. The predominant cellular fatty acids were C12:0, C16:0, C18:1 ω9c, and C12:0 3OH. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. According to phenotypic, genotypic, and chemotaxonomic analyses, strain CAU 1620T represents a novel species of the genus Marinobacter, for which the name Marinobacter arenosus sp. nov. is proposed. The type strain is CAU 1620T (= KCTC 82431T = MCCC 1K06079T).

Arenibacterium arenosum sp. nov., isolated from sea sand.

A Gram-negative, non-motile, short rod-shaped aerobic bacterial strain CAU 1593T was isolated from a coastal sand sample collected in the Republic of Korea. Cells of strain CAU 1593T grew optimally at 30 °C and pH 7.5 in 4% (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CAU 1593T had the highest similarity to Arenibacterium halophilum (97.5%). The whole genome of strain CAU 1593T was 3,979,826 bp with 26 contigs, and the DNA G + C content was 64.3 mol%. The major fatty acid of strain CAU 1593 T was summed feature 8 (C18:1 ω7c/C18:1 ω6c). Q-10 was the only respiratory quinone. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two phosphoglycolipids, an unidentified glycolipid, and an unidentified lipid. Based on the results of chemotaxonomic, phylogenetic, and phenotypic analyses, strain CAU 1593T represents a novel species in the genus Arenibacterium, which is named Arenibacterium arenosum sp. nov. The type strain is CAU 1593T (= KCTC 82402T = MCCC 1K05671T).