• Journal of Microbiology
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• v.45 no.6
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• pp.505-509
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• 2007

An obligately aerobic bacterium, strain KOPRI $20902^T$, was isolated from a marine sediment in Ny-${\AA}$lesund, Spitsbergen Islands, Norway. Cells were irregular rods and motile with polar monotrichous flagellum. The optimum growth temperature was $17-22^{\circ}C$. 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 $Ca^{2+}$ or $Mg^{2+}$ 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 [$C_{16:1}\;{\omega}7c/15:0$ iso 2OH (45.3%), $C_{16:0}$ (18.4%), ECL 11.799 (11.2%), $C_{10:0}$ 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 $20902^T$ (=KCTC $12566^T$=JCM $13441^T$) is the type strain of Dasania marina.

• Biodesign
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• v.6 no.4
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• pp.84-91
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• 2018

Spo0F is a response regulator that modulates sporulation, undergoes phosphorylation for phosphorelay signal transduction, and interacts with various regulatory proteins; however, the mechanisms through which phosphorylation induces structural changes and regulates interactions with binding partners remain unclear. Here, we determined the unphosphorylated crystal structure of Spo0F from the psychrophilic bacterium Paenisporosarcina sp. TG-14 (PaSpo0F) and established a phosphorylation-state structural model. We found that PaSpo0F underwent structural changes (Lys54 and Lys102) by phosphorylation and generated new interactions (Lys102/Gln10 and Lys54/Glu84) to stabilize the ${\beta}4/{\alpha}4$ and ${\beta}1/{\alpha}1$ loop structures, which are important target-protein binding sites. Analysis of Bacillus subtilis Spo0 variants revealed movement by BsSpo0F Thr82 and Tyr84 residues following interaction with BsSpo0B, providing insight into the movement of corresponding residues in PaSpo0F (Thr80 and Tyr82), with further analysis of BsSpo0F/BsRapH interaction revealing alterations in the ${\beta}4/{\alpha}4$ loop region. These results suggest that phosphorylation-induced structural rearrangement might be essential for PaSpo0F activation and expand the understanding of Spo0F-specific activation mechanisms during sporulation.

• KSBB Journal
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• v.30 no.6
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• pp.345-349
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• 2015

Antifreeze proteins (AFP) inhibit growth and recrystallization of ice, and permit organisms to survive in cold environments. The AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris icebinding protein), was produced in E. coli using a cold shock induction system. The culture temperature was shifted from $37^{\circ}C$ to $15^{\circ}C$ and a 20 L culture scale was used. The final weights of dried cell and FfIBP were estimated to be 126 g and 8.4 g, respectively. The thermal hysteresis (TH) activity ($1.53^{\circ}C$) of the produced FfIBP was 3.6-fold higher than that of the LeIBP (Leucosporidium ice-binding protein) produced in Picha. The current study demonstrates that large-scale production of FfIBP was successful and the result could be extended to further application studies using recombinant AFPs.

• KSBB Journal
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• v.29 no.4
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• pp.278-284
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• 2014

We present microfluidic method to rapidly analyze the effect of temperature on the change of morphologies of Antarctic bacteria (Pseudoalteromonas sp., Shewanella vesiculosa, Shewanella sp., and Cellulophaga sp.). The microfluidic device is able to generate stable temperature gradient from 7 to$40^{\circ}C$ and dramatically reduce the number of experiments, experimental cost and labor, and amount of sample. Based on this approach, we found that specific bacteria transforming morphology into filament or elongated body strongly depends on cultivation temperature. Interestingly, we found that the morphologies of Pseudoalteromonas sp., Shewanella vesiculosa, Shewanella sp., and Cellulophaga sp. are elongated at below $25^{\circ}C$, above $20^{\circ}C$, above $15^{\circ}C$ and above $35^{\circ}C$, respectively. We envision the microfluidic device is a useful approach to analyze biological events with a high throughput manner.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.405-413
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• 2004

The rheological properties of an exopolysaccharide, EPS-R, produced by the marine bacterium Hahella chejuensis strain 96CJ 10356 were investigated. The $E_{24}$ of $0.5\%$ EPS-R was $89.2\%$, which was higher than that observed in commercial polysaccharides such as xanthan gum ($67.8\%$), gellan gum ($2.01\%$) or sodium alginate ($1.02\%$). Glucose and galactose are the main Sugars in EPS-R, with a molar ratio of ${\~}1:6.8$, xylose and ribose are minor sugar components. The average molecular mass, as determined by gel filtration chromatography, was $2.2{\times}10^3$ KDa, The intrinsic viscosities of EPS-R were calculated to be 16.5 and 15.9 dL/g using the Huggins and Kraemer equations, respectively, with a 2.3 dL/g overlap. In terms of rigidity, the conformation of EPS-R was similar to that of caboxymethyl cellulose ($5.0{\times}10^{-2}$). The rheological behavior of EPS-R dispersion indicated that the formation of a structure intermediate between that of a random-coil polysaccharide and a weak gel. The aqueous dispersion of EPS-R at concentrations ranging from 0.25 to $1.0\%$ (w/w) showed a marked shear-thinning property in accordance with Power-law behavior. In aqueous dispersions of $1.0\%$ EPS-R, the consistency index (K) and flow behavior index (n) were 1,410 and 0.73, respectively. EPS-R was Stable to pH and salts.

• KSBB Journal
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• v.29 no.4
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• pp.303-306
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• 2014

Antifreeze proteins (AFP) inhibit ice growth to permit the survival of polar organisms in the cold environments. The recombinant AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris ice-binding protein), was produced using Pichia pastoris expression system. The optimum fermentation temperature ($30^{\circ}C$) and pH (5) for FfIBP production were determined using a fed-batch culture system. The maximal cell density and purified FfIBP were 112 g/L and 70 mg/L, respectively. The thermal hysteresis (TH) activity (0.85) of FfIBP obtained using a glycerol-methanol fed-batch culture system was 2-fold higher than that of the LeIBP (Leucosporidium ice-binding protein). This work allows for large-scale production of FfIBP, which could be extended to further application studies using recombinant AFPs.

• Proceedings of the Microbiological Society of Korea Conference
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• 2006.05a
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• pp.97-99
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• 2006

A chitinase-producing bacterium strain KCTC10714 was isolated from sea sand around the King Sejong Station, King George Island in Antarctica. It was identified as Sanguibacter sp., based on the biochemical properties and 16S rRNA gene sequence. KCTC10714 chitinase showed enzyme activity in broad range of temperature from 0 to $70^{\circ}C$. At $0^{\circ}C$, it showed 70.9% of relative activity in comparison with 100%. The chitinase gene of KCTC10714 was cloned using inverse PCR cloning method. KCTC10714 chitinase gene was designated as chi21702. The ORF of chi21702 consisted of 1,449 bp (482 amino acid), and contained ChtBD3 (a chitin/cellulose binding domain) and an active site for chitinase family 18.

• Korean Journal of Pharmacognosy
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• v.49 no.2
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• pp.108-112
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• 2018

Four quinolone alkaloids, 2-heptyl-4-quinolone (1), 2-nonyl-4-quinolone (2), 2-undecyl-4-quinolone (3), and 2-undecen-1'-yl-4-quinolone (4), together with two nitrogen derived benzoic acid derivatives, N-acetylanthranilic acid (5) and o-acetamidobenzamide (6) have been isolated from the Arctic bacterial strain, Pseudomonas aeruginosa. The structures of the compounds were determined by 1D and 2D NMR, and MS experiments, as well as by comparison of their data with published values. To the best of our knowledge, compounds 3-6 were isolated for the first time from P. aeruginosa.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.415-420
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• 2016

Chemical study of an Arctic bacterium, Pseudomonas aeruginosa (Pseudomonadaceae) led to the isolation of two diketopiperazines 1 and 2, two phenazine alkaloids 3 and 4, and an indole carbaldehyde 5, along with a benzoic acid derivative 6. The structures of the compounds were confirmed by 1D and 2D NMR, and MS experiments, as well as by comparison of their data with published values. Among the isolates, compounds 5 and 6 were isolated for the first time from P. aeruginosa of the seawater of Arctic Chuckchi Sea. Antimicrobial activities of compounds 1‒6 against a Staphylococcus aureus and Candida albicans were evaluated.

• Research in Plant Disease
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• v.29 no.4
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• pp.399-404
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• 2023

Agricultural activities and the number of farms in the subarctic regions have been increasing annually after the coronavirus disease 2019 pandemic to achieve food self-sufficiency. Potatoes are vulnerable to soft rot bacteria at all stages of production, storage, and transportation. A novel bacterium, Pseudomonas sp. N3-W, isolated from Alaska tundra soil, grows at 5-25℃ and produces extracellular protease(s). N3-W caused necrotic spots (hypersensitivity) in hot pepper leaves and soft rot disease (pathogenicity) in potato tubers. The psychrotolerant N3-W caused significant soft rot symptoms on potatoes at a broad temperature range (5℃, 15℃, and 25℃). In contrast, mesophilic Pectobacterium carotovorum KACC 16999 induced severe rotting symptoms in potatoes at their optimal growth temperature of 15℃ and 25℃. However, it barely produced symptoms at 5℃, which is the appropriate storage and transportation temperature for potatoes. The results of pathogenicity testing imply that psychrotolerant soft rot pathogens from polar regions may cause severe soft rot not only during the crop growing season but also during storage and transportation. Our study indicates the possibility of new plant pathogen emergence and transmission due to the expansion of crop cultivation areas caused by permafrost thawing in response to recent polar warming.