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A Gram-stain-negative, non-motile, oxidase- and catalase-positive, rod-shaped bacterium was isolated from a coastal seawater sample from the Arctic Circle and designated strain IMCC9719 T . On the basis of 16S rRNA gene sequence analysis, it was shown that strain IMCC9719 T belonged to the genus Leucothrix and was closely related to the type strains of Leucothrix pacifica (97.6 % similarity) and Leucothrix mucor (95.1 %), while the strain shared <90.6 % sequence similarity with other bacterial species. The average nucleotide identity and genome-to-genome distance values between strain IMCC9719 T and L. pacifica JCM 18388 T were 71.7 and 16.9 %, respectively. The DNA G+C content of strain IMCC9719 T was 43.5 mol%. Optimum growth of strain IMCC9719 T was observed at 15 °C, at pH 7.5-8.5 and in the presence of 2.0-2.5 % (w/v) NaCl. The major fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and C16 : 0. Cells of strain IMCC9719 T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified polar lipid, an unidentified aminophospholipid and two unidentified phospholipids. The major respiratory quinone was ubiquinone-8 (Q-8). Based on the taxonomic data collected in this study, strain IMCC9719 T represents a novel species of the genus Leucothrix, for which the name Leucothrix arctica sp. nov. is proposed. The type strain is IMCC9719 T (=KACC 18010 T =NBRC 110382 T ).

The diversity and physiological characteristics of culturable bacteria associated with lichens from different habitats of the Arctic and Antarctica were investigated. The 68 retrieved isolates could be grouped on the basis of their 16S rRNA gene sequences into 26 phylotypes affiliated with the phyla Actinobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes and with the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Isolates belonging to the Alphaproteobacteria were the most abundant, followed by those belonging to Actinobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus. Phylogenetic analysis showed that approximately 21 % of the total isolates represented a potentially novel species or genus (≤97 % sequence similarity). Strains belonging to the genera Sphingomonas, Frondihabitans, Hymenobacter, and Burkholderia were recovered from lichen samples from both geographic locations, implying common and important bacterial functions within lichens. Extracellular protease activities were detected in six isolates, affiliated with Burkholderia, Frondihabitans, Hymenobacter, Pseudomonas, and Rhodanobacter. Extracellular lipase activities were detected in 37 isolates of the genera Burkholderia, Deinococcus, Frondihabitans, Pseudomonas, Rhodanobacter, Sphingomonas, and Subtercola. This is the first report on the culturable bacterial diversity present within lichens from Arctic and Antarctica and the isolates described herein are valuable resources to decode the functional and ecological roles of bacteria within lichens. In addition, the low similarity (≤97 %) of the recovered isolates to known species and their production of cold-active enzymes together suggest that lichens are noteworthy sources of novel bacterial strains for use in biotechnological applications.

A new approach for enrichment culture was applied to obtain cold-active protease-producing bacteria for marine and terrestrial samples from Svalbard, Norway. The method was developed for the enrichment of bacteria by long-term incubation at low temperatures in semi-solid agar medium containing meat pieces as the main source of carbon and energy. ZoBell and 0.1x nutrient broth were added for marine and terrestrial microorganisms, respectively, to supply basal elements for growth. One to three types of colonies were observed from each enrichment culture, indicating that specific bacterial species were enriched during the experimental conditions. Among 89 bacterial isolates, protease activity was observed from 48 isolates in the screening media containing skim milk. Good growth was observed at 4 degrees C and 10 degrees C while none of the isolates could grow at 37 degrees C. At low temperatures, enzyme activity was equal to or higher than activity at higher temperatures. Bacterial isolates were included in the genera Pseudoalteromonas (33 isolates), Arthrobacter (24 isolates), Pseudomonas (16 isolates), Psychrobacter (6 isolates), Sphingobacterium (6 isolates), Flavobacterium (2 isolates), Sporosarcina (1 isolate), and Stenotrophomonas (1 isolate). Protease activity was observed from Pseudoalteromonas (33 isolates), Pseudomonas (10 isolates), Arthrobacter (4 isolates), and Flavobacterium (1 isolate).

A Gram-negative, non-motile, aerobic bacterium, designated strain KOPRI 20941(T), was isolated from a sample of marine sediment from Ny Alesund, Spitsbergen, Norway. A phylogenetic analysis based on 16S rRNA gene sequences revealed that the Arctic isolate nested within the genus Maribacter and showed the highest sequence similarity (98.1 %) with respect to Maribacter orientalis KMM 3947(T). Chemotaxonomic data (DNA G+C content of 36 mol%; MK-6 as the major respiratory quinone and iso-C(17 : 0) 3-OH, C(16 : 1)omega7c/iso-C(15 : 0) 2-OH and iso-C(15 : 0) as the major fatty acids) supported the affiliation of strain KOPRI 20941(T) to the genus Maribacter. The results of phylogenetic analyses, physiological and biochemical tests and a DNA-DNA reassociation test (<54 % relatedness) allowed genotypic and phenotypic differentiation of the strain from the recognized species of the genus Maribacter. Therefore strain KOPRI 20941(T) represents a novel species of the genus Maribacter, for which the name Maribacter arcticus sp. nov. is proposed. The type strain is KOPRI 20941(T) (=KCTC 22053(T)=JCM 14790(T)).

Proteorhodopsin (PR), a retinal-containing seven transmembrane helix protein, functions as a light-driven proton pump. Using PCR, we isolated 18 PR variants originating from the surface of the Arctic Ocean. Their absorption maxima were between 517 and 546 nm at pH 7. One of the isolates turned out to be identical to GPR (green light-absorbing proteorhodopsin) from Monterey Bay. Interestingly, 10 isolates had replaced a tyrosine in the retinal-binding site (Tyr200 in GPR) with Asn. They showed a slower photocycle, more blue-shifted absorption maxima at pH 10, and relatively larger DeltaH and DeltaS of activation of the transition between the O intermediate and the ground state compared to GPR.

An obligately aerobic bacterium, strain KOPRI 20902T, was isolated from a marine sediment in Ny-Arlesund, Spitsbergen Islands, Norway. Cells were irregular rods and motile with polar monotrichous flagellum. The optimum growth temperature was 17-22 degrees . Cells grew best in pH 7.0-10.0 and 3-4% sea salts (corresponding to 2.3-3.1% NaCl). The novel strain required Ca2+ or Mg2+ in addition to NaCl for growth. Sequence analysis of 16S rRNA gene revealed that the Arctic isolate is distantly related with established species (<92.4% sequence similarity) and formed a monophyletic group with Cellvibrio, which formed a distinct phylogenetic lineage in the order Pseudomonadales. Predominant cellular fatty acids [C16:1 omega7c/15:0 iso 2OH (45.3%), C16:0 (18.4%), ECL 11.799 (11.2%), C10:0 3OH (10.4%)]; DNA G+C content (37.0 mol%); nitrate reduction to nitrogen; absence of aesculin hydrolysis, N-acetyl-beta-glucosaminidase and esterase; no assimilation of arabinose, galactose, glucose, lactose, maltose, and trehalose differentiated the strain from the genus Cellvibrio. Based on the phylogenetic and phenotypic characteristics, Dasania marina gen. nov., sp. nov. is proposed in the order Pseudomonadales. Strain KOPRI 20902T (=KCTC 12566T=JCM 13441T) is the type strain of Dasania marina.

Polar organisms should have mechanisms to survive the extremely cold environment. Four genes encoding cold-shock proteins, which are small, cold-induced bacterial proteins, have been cloned from the Antarctic bacterium Streptomyces sp. AA8321. Since the specific functions of any polar bacterial or Streptomyces cold-shock proteins have not yet been determined, we examined the role of cold-shock protein A from Streptomyces sp. AA8321 (CspA(St)). Gel filtration chromatography showed that purified CspA(St) exists as a homodimer under physiological conditions, and gel shift assays showed that it binds to single-stranded, but not double-stranded, DNA. Overexpression of CspA(St) in Escherichia coli severely impaired the ability of the host cells to form colonies, and the cells developed an elongated morphology. Incorporation of a deoxynucleoside analogue, 5-bromo-2'-deoxyuridine, into newly synthesized DNA was also drastically diminished in CspA(St)-overexpressing cells. These results suggest that CspA(St) play a role in inhibition of DNA replication during cold-adaptation.