Genome sequence of "Candidatus Aquiluna" sp. strain IMCC13023, a marine member of the Actinobacteria isolated from an arctic fjord

We report the genome sequence of actinobacterial strain IMCC13023, isolated from arctic fjord seawater. Phylogenetic analysis of 16S rRNA gene showed that the strain is related to "Candidatus Aquiluna rubra." The genome information suggests that strain IMCC13023 is a photoheterotroph carrying actinorhodopsin, with the smallest genome ever reported for a free-living member of the Actinobacteria.     

Complete genome sequence of strain IMCC9063, belonging to SAR11 subgroup 3, isolated from the Arctic Ocean

Strain IMCC9063 is a novel isolate of the SAR11 clade and is distantly related to other cultured representatives in this clade. The strain was isolated off the coast of Svalbard, Norway, by applying high-throughput culturing methods based on dilution to extinction. Here we present the finished genome sequence of strain IMCC9063.     

Genome sequence of strain IMCC1989, a novel member of the marine gammaproteobacteria

Strain IMCC1989 is a novel member of the oligotrophic marine Gammaproteobacteria (OMG) group and is closely related with a symbiont group of the genera Teredinibacter and "Candidatus Endobugula." Here we present the genome sequence of strain IMCC1989, which was isolated from the Yellow Sea by using dilution-to-extinction culturing.     

Genome sequence of strain IMCC3088, a proteorhodopsin-containing marine bacterium belonging to the OM60/NOR5 clade

Strain IMCC3088, cultivated from the Yellow Sea, is a novel isolate belonging to the OM60/NOR5 clade and is closely related to clone OM241, Congregibacter litoralis, and strain HTCC2080. Here, the genome sequence of strain IMCC3088 is presented, showing the absence of photosynthetic gene clusters and the presence of proteorhodopsin.     

Genome sequence of strain IMCC2047, a novel marine member of the Gammaproteobacteria

Strain IMCC2047 was isolated from the Yellow Sea using dilution-to-extinction culturing. The strain was shown to occupy a distinct phylogenetic position within the Gammaproteobacteria. Here we present the genome sequence of strain IMCC2047, which harbors genes for various metabolic pathways, including proteorhodopsin and ribulose bisphosphate carboxylase.     

Genome Sequence of Strain IMCC14465, Isolated from the East Sea,Belonging to the PS1 Clade of Alphaproteobacteria

Strain IMCC14465 was isolated from surface seawater of the East Sea using dilution-to-extinction culturing. Phylogenetic analysis indicated that the strain belongs to the PS1 clade, which is closely related to the OCS116 clade in the Alphaproteobacteria. Here, we report the genome sequence of IMCC14465, the first isolate of the PS1 clade.     

Aequoribacter fuscus gen. nov., sp. nov., a new member of the family Halieaceae,isolated from coastal seawater

A Gram-stain-negative, rod-shaped, obligately aerobic, nonflagellated, and chemoheterotrophic bacterium, designated IMCC3088T, was isolated from coastal seawater of the Yellow Sea. The 16S rRNA gene sequence analysis indicated that this strain belonged to the family Halieaceae which shared the highest sequence similarities with Luminiphilus syltensis NOR5-1BT (94.5%) and Halioglobus pacificus S1-72T (94.5%), followed by 92.3–94.3% sequence similarities with other species within the aforementioned family. Phylogenetic analyses demonstrated that strain IMCC3088T was robustly clustered with Luminiphilus syltensis NOR5-1BT within the family Halieaceae. However, average amino acid identity (AAI), percentages of conserved proteins (POCP), average nucleotide identity (ANI), and alignment fraction (AF) between strain IMCC3088T and Luminiphilus syltensis NOR5-1BT were 54.5%, 47.7%, 68.0%, and 16.5%, respectively, suggesting that they belonged to different genera. Whole-genome sequencing of strain IMCC3088T revealed a 3.1 Mbp genome size with a DNA G + C content of 51.7 mol%. The genome encoded diverse metabolic pathways including sulfur oxidation, phenol degradation, and proteorhodopsin phototrophy. Mono-unsaturated fatty acids were found to be the predominant cellular fatty acid components in the strain. Phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were the primarily identified polar lipids, and ubiquinone-8 was identified as a major respiratory quinone. The taxonomic data collected herein suggested that strain IMCC3088T represented a novel genus and species of the family Halieaceae, for which the name Aequoribacter fuscus gen. nov., sp. nov. is proposed with the type strain (= KACC 15529T = NBRC 108213T).     

Complete genome sequence of marinomonas bacteriophage p12026

Members of the genus Marinomonas in the Gammaproteobacteria are broadly distributed in marine environments where they could be infected by bacteriophages. Here we report the genome sequence of bacteriophage P12026 that can lytically infect bacterial strain IMCC12026, a member of the genus Marinomonas. To our knowledge, this is the first genome sequence of a lytic bacteriophage infecting the genus Marinomonas.     

Complete Genome Sequences of Two Persicivirga Bacteriophages, P12024S and P12024L

The phylum Bacteroidetes is one of the major bacterial phyla in marine environments, where bacteriophages are highly abundant. Bacteriophages infecting members of the phylum Bacteroidetes, however, have not been well represented in public genome databases. Here we announce the genome sequences of two bacteriophages, P12024S and P12024L, that were isolated from coastal seawater and lytically infect Persicivirga sp. IMCC12024, a marine Bacteroidetes bacterium.     

Complete genome sequence of Celeribacter bacteriophage P12053L

The Roseobacter clade has been recognized as one of the abundant bacterial lineages in marine environments, which makes the characterization of bacteriophages infecting members of the clade important. Here we report the complete genome sequence of bacteriophage P12053L, which infects Celeribacter sp. strain IMCC12053, a member of the Roseobacter clade.     

Grimontia marina sp. nov., a marine bacterium isolated from the Yellow Sea

A novel species belonging to the genus Grimontia is described in this study. A Gram-negative, chemoheterotrophic, obligately aerobic, catalase- and oxidase-positive, motile by a single polar flagellum, and rod-shaped bacterium, designated IMCC5001^T, was isolated from surface seawater of the Yellow Sea. Strain IMCC5001^T grew optimally at 30°C in the presence of 3.5% NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was related most closely to Grimontia hollisae with a sequence similarity of 95.8%, and formed a robust phyletic lineage with Grimontia hollisae. Differential physiological characteristics between the new strain and Grimontia hollisae KCCM 41680^T and chemotaxonomic characterization including determination of DNA G+C content, fatty acid methyl esters, quinone composition, and polar lipid profiles justified the assignment of strain IMCC5001^T to the genus Grimontia as a novel species. In conclusion, strain IMCC5001^T represents a new species, for which the name Grimontia marina sp. nov. is proposed, with the type strain IMCC5001^T (=KCTC 22666^T =NBRC 105794^T).     

<Emphasis Type="Italic">Pedobacter aquicola</Emphasis> sp. nov., isolated from freshwater

A non-motile, pink-pigmented bacterial strain designated IMCC25679^T, was isolated from freshwater Lake Chungju of Korea. Phylogenetic trees based on 16S rRNA gene sequences showed that the strain IMCC25679^T formed a lineage within the genus Pedobacter. The strain IMCC25679^T was closely related to Pedobacter daechungensis Dae 13^T (96.4% sequence similarity), Pedobacter rivuli HME8457^T (95.3%) and Pedobacter lentus DS-40^T (94.3%). The major fatty acids of IMCC- 25679^T were iso-C_15:0, iso-C_16:0 and summed feature 3 (comprising C_16:1ω6c and/or C_16:1ω7c). The major respiratory quinone was MK-7. The major polar lipids were phosphatidylethanolamine (PE), an unidentified sphingolipid (SL), an unidentified aminolipid (AL) and three unidentified polar lipids (PL). The DNA G + C content of IMCC25679^T was 32.2 mol%. Based on the evidence presented in this study, the strain IMCC25679^T represents a novel species within the genus Pedobacter, with the proposed name Pedobacter aquicola, sp. nov. The type strain is IMCC25679^T (= KACC 19486^T = NBRC113131^T).     

Photochemical characterization of flavobacterial rhodopsin: The importance of the helix E region for heat stability

Although many microbial rhodopsins have been discovered many of organisms in a variety of habitats, little is known about the property and diversity of rhodopsin in flavobacteria. Recent studies discovered that many proteorhodopsin (PR)-like proteins exist in genomes of flavobacteria. Following the isolation of a flavobacterial rhodopsins (FR) from the flavobacteria IMCC1997 from the East Sea of Korea, we characterized its photochemical features. We confirmed that the FR expression is induced by light in the IMCC1997 cell. Upon receiving light energy in vitro, the proton acceptor (D83) and donor (E94) of the FR translocate protons from intracellular to extracellular regions. Compared with proteorhodopsin (PR), the FR from IMCC 1997 cells is very unstable, which may be explained by their primary sequence differences. The ratio of all trans/13-cis retinal conformation does not influence this stability. To measure the stability of FR, we tested heat endurance at 70 °C and found that the heat endurance time of some FR mutants increased. Based upon these results, we found the helix E of this protein to be critical for the unstability of FR.     

<Emphasis Type="Italic">Marinobacterium marisflavi</Emphasis> sp. nov., Isolated from a Costal Seawater

A marine bacterium designated strain IMCC4074^T was isolated from surface seawater collected off Incheon Port, the Yellow Sea, and subjected to a polyphasic taxonomy. The strain was Gram-negative, chemoheterotrophic, slightly halophilic, strictly aerobic, and motile rods. Based on 16S rRNA gene sequence comparisons, the strain was most closely related to Marinobacterium litorale KCTC 12756^T (93.9%) and shared low 16S rRNA gene sequence similarities with members of the genus Marinobacterium (91.8–93.9%) and the genus Neptunomonas (93.4%) in the order Oceanospirillales. Phylogenetic analyses showed that this marine isolate formed an independent phyletic line within the genus Marinobacterium clade. The DNA G+C composition of the strain was 56.0 mol% and the predominant constituents of the cellular fatty acids were C_16:0 (28.0%), C_16:1 ω7c and/or iso-C_15:0 2-OH (19.3%), C_18:1 ω7c (17.8%), and C_17:1 cyclo (12.5%), which differentiated the strain from other Marinobacterium species. Based on the taxonomic data collected in this study, only a distant relationship could be found between strain IMCC4074^T and other members of the genus Marinobacterium, thus the strain represents a novel species of the genus Marinobacterium, for which the name Marinobacterium marisflavi sp. nov. is proposed. The type strain of Marinobacterium marisflavi is IMCC4074^T (= KCTC 12757^T = LMG 23873^T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain IMCC4074^T is EF468717. An erratum to this article can be found at     

Granulosicoccaceae fam. nov., to include Granulosicoccus antarcticus gen. nov., sp. nov., a non-phototrophic, obligately aerobic chemoheterotroph in the order Chromatiales, isolated from Antarctic seawater

A Gram-negative, motile by tuft flagella, obligately aerobic chemoorganoheterotrophic, sphere-form bacterium, designated IMCC3135(T), was isolated from the Antarctic surface seawater of King George Island, West Antarctica. The strain was mesophilic, neutrophilic, and requiring NaCl for growth, but neither halophilic nor halotolerant. The 16S rRNA gene sequence analysis indicated that the strain was most closely related to genera of the order Chromatiales in the class Gammaproteobacteria. The most closely related genera showed less than 90% 16S rRNA gene sequence similarity and included Thioalkalispira (89.9%), Thioalkalivibrio (88.0%-89.5%), Ectothiorhodospira (87.9%-89.3%), Chromatium (88.3%-88.9%), and Lamprocystis (87.7%-88.9%), which represent three different families of the order Chromatiales. Phylogenetic analyses showed that this Antarctic strain represented a distinct phylogenetic lineage in the order Chromatiales and could not be assigned to any of the defined families in the order. Phenotypic characteristics, including primarily non-phototrophic, non-alkaliphilic, non-halophilic, and obligately aerobic chemoheterotrophic properties, differentiated the strain from other related genera. The very low sequence similarities (<90%) and distant relationships between the strain and members of the order suggested that the strain merited classification as a novel genus within a novel family in the order Chromatiales. On the basis of these taxonomic traits, a novel genus and species is proposed, Granulosicoccus antarcticus gen. nov., sp. nov., in a new family Granulosicoccaceae fam. nov. Strain IMCC3135(T) (=KCCM 42676(T)=NBRC 102684(T)) is the type strain of Granulosicoccus antarcticus.     

<Emphasis Type="Italic">Antarcticimonas flava</Emphasis> gen. nov., sp. nov., isolated from Antarctic coastal seawater

A marine bacterium, designated IMCC3175^T, was isolated from a seawater sample collected off the Antarctic coast. The strain was Gram-negative, obligately aerobic, carotenoid pigment-containing, and rod-shaped bacterium that divided by binary fission. As determined by 16S rRNA gene sequence comparisons, the most closely related genera were Formosa (92.9∼93.3%), Bizionia (91.6∼93.2%), Gaetbulibacter (91.5∼92.8%), Sediminibacter (92.7%), Yeosuana (92.6%), Subsaximicrobium (92.1∼92.2%), and Gillisia (89.5∼92.2%). Phylogenese analysis based on 16S rRNA gene sequences showed that the strain formed a monophyletic clade together with the genera Sediminibacter and Subsaximicrobium but represented an independent phyletic line in this clade of the family Flavobacteriaceae. The DNA G+C content of the strain was 37.3 mol%. The major respiratory quinone was MK-6 and the predominant cellular fatty acids were C_16:1 ω7c and/or iso-C_15:0 2-OH (12.8%), anteiso-C_15:0 (9.4%), and iso-C_16:1 (9.4%). Low 16S rRNA gene sequence similarity, formation of a distinct phylogenetic branch, and several phenotypic characteristics, including a narrow range of temperature and salinity for growth, differentiated strain IMCC3175^T from other related genera in the family Flavobacteriaceae. Therefore the name Antarcticimonas flava gen. nov., sp. nov. is proposed, with strain IMCC3175^T (=KCCM 42713^T =NBRC 103398^T) as the type strain.     

A pathogenic 15-base pair deletion in mitochondrial DNA-encoded cytochrome c oxidase subunit III results in the absence of functional cytochrome c oxidase

A 15-base pair, in-frame, deletion (9480del15) in the mitochondrial DNA (mtDNA)-encoded cytochrome c oxidase subunit III (COX III) gene was identified previously in a patient with recurrent episodes of myoglobinuria and an isolated COX deficiency. Transmitochondrial cell lines harboring 0, 97, and 100% of the 9480del15 deletion were created by fusing human cells lacking mtDNA (rho(0) cells) with platelet and lymphocyte fractions isolated from the patient. The COX III gene mutation resulted in a severe respiratory chain defect in all mutant cell lines. Cells homoplasmic for the mutation had no detectable COX activity or respiratory ATP synthesis, and required uridine and pyruvate supplementation for growth, a phenotype similar to rho(0) cells. The cells with 97% mutated mtDNA exhibited severe reductions in both COX activity (6% of wild-type levels) and rates of ATP synthesis (9% of wild-type). The COX III polypeptide in the mutant cells, although translated at rates similar to wild-type, had reduced stability. There was no evidence for assembly of COX I, COX II, or COX III subunits in a multisubunit complex in cells homoplasmic for the mutation, thus indicating that there was no stable assembly of COX I with COX II in the absence of wild-type COX III. In contrast, the COX I and COX II subunits were assembled in cells with 97% mutated mtDNA.     

Heliorhodopsin binds and regulates glutamine synthetase activity

Photoreceptors are light-sensitive proteins found in various organisms that respond to light and relay signals into the cells. Heliorhodopsin, a retinal-binding membrane protein, has been recently discovered, however its function remains unknown. Herein, we investigated the relationship between Actinobacteria bacterium IMCC26103 heliorhodopsin (AbHeR) and an adjacent glutamine synthetase (AbGS) in the same operon. We demonstrate that AbHeR binds to AbGS and regulates AbGS activity. More specifically, the dissociation constant (K_d) value of the binding between AbHeR and AbGS is 6.06 μM. Moreover, the absence of positively charged residues within the intracellular loop of AbHeR impacted K_d value as they serve as critical binding sites for AbGS. We also confirm that AbHeR up-regulates the biosynthetic enzyme activity of AbGS both in vitro and in vivo in the presence of light. GS is a key enzyme involved in nitrogen assimilation that catalyzes the conversion of glutamate and ammonia to glutamine. Hence, the interaction between AbHeR and AbGS may be critical for nitrogen assimilation in Actinobacteria bacterium IMCC26103 as it survives in low-nutrient environments. Overall, the findings of our study describe, for the first time, to the best of our knowledge, a novel function of heliorhodopsin as a regulatory rhodopsin with the capacity to bind and regulate enzyme activity required for nitrogen assimilation.

A study of heliorhodopsin, an actinobacterial photoreceptor of unknown function, reveals that it interacts with glutamine synthetase, an enzyme involved in nitrogen assimilation, and regulates its activity in the presence of light, highlighting the diverse functions of rhodopsins in different organisms.     

Enhancement of chrysogenin production in cultures of Penicillium chrysogenum by uronic acid oligosaccharides

Additions of 50 to 100 g of acid-hydrolysed alginate oligosaccharides ml^–1 and enzyme-hydrolysed pectin oligosaccharides to 24- to 48-h cultures of Penicillium chrysogenum, ATCC 9480, led to enhanced production of chrysogenin by over 30 to 40% in shaken flasks and bioreactors. Some of the oligosaccharides also promoted biomass formation but were not used as a carbon source.