• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.333-338
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• 2012

Lichens are a symbiosis between fungi, algae and cyanobacteria. Our group recently studied the antioxidant properties of some bacterial species isolated from Arctic lichens and we confirmed that they possess high antioxidant activities. In this paper, we investigated the antioxidant capacity of 5 microorganisms newly isolated from 4 Arctic lichen species, Cladonia sp., Sterocaulon sp., Umbilicaria sp. and Cetraria sp., using various solvent extractions. We carried out 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity test and ferric reducing antioxidant power (FRAP) assay. Also total phenolic and flavonoid content assays were performed. Among the bacterial culture extracts of the tested lichen-microorganisms, ethyl acetate extracts of Burkholderia sordidicola S5-B(T) had not only a high antioxidant activity (72.9%) when compared with the ascorbic acid used as the control (51.3%) in the DPPH assay, but also a high amount of phenolic content as well as flavonoid content. As a result, these lichen-microorganisms may be potentially useful sources of natural antioxidants.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.64-66
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• 2017

Caballeronia sordidicola strain PAMC 26592 was isolated from Umbilicaria sp., a lichen material collected from Svalbard Archipelago in the Arctic Ocean. We report the draft genome sequence of the strain PAMC 26592, a metabolic generalist. As we have observed in previous genomic studies in the genus Caballeronia draft genomic sequences of PAMC 26592 had an assortment of genes of ecological importance and of bio-technical potentials, which include diverse metabolic genes for carbohydrates, aromatic compounds, amino acids, and vitamins, and genes for nitrogen / sulfur metabolisms, stress responses, membrane transporters, antibiotic resistance, and heavy metal resistance.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.17-24
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• 2019

Bacteria in the polar region are under strong light and ultraviolet radiation. In this study, we investigated the effects of light on the growth of a psychrophilic bacterium, Sphingomonas sp. PAMC 26621, isolated from an Arctic lichen Cetraria sp. The growth of the strain in the light was lower than that in the dark. Surprisingly, thiamine increased the growth of Sphingomonas sp. PAMC 26621 in M9 minimal medium under light conditions. Thiamine increased the growth of the strain in a concentration-dependent manner along with ascorbic acid. N-acetylcysteine had no effect on the growth of the strain in the light. Thiamine and ascorbic acid also increased the activities of glucose-6-phosphate dehydrogenase and superoxide dismutase. The results of this study indicate that thiamine provided by the lichen symbiosis system plays an important role in light-induced oxidative stress in this Arctic bacterium as an antioxidant. Our study provide insight into the biochemistry and physiology of Arctic bacteria under strong light and ultraviolet radiation.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.350-357
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• 2013

Lichens are symbiotic organisms composed of fungi, algae, or cyanobacteria which are able to survive in extreme environmental conditions ranging from deserts to polar areas. Some lichen symbionts produce a wide range of secondary metabolites that have many biological activities such as antibacterial, antifungal, antiviral, antitumor, antioxidant and anti-inflammatory etc. Among the symbionts of lichens, of the bacterial communities of lichen symbionts little is known. In this study, we isolated 4 microbial species from the Arctic lichen Stereocaulon spp. and evaluated their antioxidant properties using 1,1-diphenyl-2-picryl-hydrazyl assay as well as 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) assay. Total phenolic contents and total flavonoid contents were also measured. A potent radical scavenging activity was detected in a number of the lichen extracts. Among the 4 species tested in this study, the ethyl acetate extract of Bosea vestrisii 36546(T) exhibited the strongest free radical scavenging activity, with an inhibition rate of 86.8% in DPPH and 75.2% in ABTS assays. Overall, these results suggest that lichen-bacteria could be a potential source of natural antioxidants.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.141-143
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• 2017

Caballeronia sordidicola strain PAMC 26577 was isolated from Cladonia sp., a lichen collected from Svalbard Archipelago in the Arctic Ocean. Draft genomic sequences of PAMC 26577 were determined using Illumina and 182 contigs were submitted to GenBank and N50 value was 159,226. The genome of PAMC 26577 was comprised of 8,334,211 base pairs and %G+C content was 59.4. The genome included 8 ribosomal RNA genes and 51 tRNA genes as non-coding sequences. Protein-coding genes were 8,065 in number and they included central metabolism genes as well as butanol/butyrate biosynthesis, polyhydroxybutyrate metabolism, serine cycle methylotrophy genes, and glycogen metabolism. Membrane transporters were more than two-hundreds in number, but sugar phosphotransferase system and TRAP transporters were lacking. PAMC 26577 lacked CRISPR-associated sequences and proteins. No transposable elements were observed and there were only limited number of phage remnant regions with 11 phage-related genes.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.137-140
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• 2017

Caballeronia sordidicola strain PAMC 26510 was isolated from Psoroma sp., a lichen material, collected from Barton Peninsula of King George Island in Antarctica. The draft genome sequence of PAMC 26510 consisted of 224 contigs and they was 7,872,143 base pairs with 59.7% G+C content. The genome included 7,580 protein coding sequences and 6 ribosomal RNA genes and 46 tRNA genes. The strain PAMC 26510 is also a metabolic generalist as we have observed in previous genomic studies in the arctic strain of Caballeronia sordidicola. The draft genomic sequences of PAMC 26510 had six CRISPR arrays on six contigs, and there were two clusters of CRISPR-associated genes that were linked with respective CRISPR arrays.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.380-388
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• 2012

A total of 5 different polar microorganisms were isolated from Arctic lichens and their bioactive compounds were extracted from cell culture using different solvents including acetone, water, chloroform, diethylether, ethanol, ethyl acetate, methanol, and petroleum ether. The antibacterial properties of the extracts were evaluated by disk diffusion tests and minimal inhibitory concentration tests against 6 bacterial pathogens; Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterobacter cloacae, Pseudomonas aeruginosa and Escherichia coli. Among the extraction samples, ethyl acetate extracts of Burkholderia sordidicola S5-$B^T$ (KOPRI 26644) showed the highest activity (inhibition zone, 7-10 mm; MIC value, 57.5-1000 ug/ml) against targeted bacteria. Among the various solvents used for extraction, chloroform extract exhibited the weakest, but still obvious, activity.