• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.193-195
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• 2001

A radiation-resistant bacterium was isolated from gamma irradiated dried laver (Porphyra tenera) and its microbiological characteristics were examined. As a result of resistance test to gamma irradiation, the isolate was survived $10^{3}$ CFU/mL even at 30 kGy and significant shoulder line zone was shown until 20 kGy. The $D_{10}$ value was 11.27 kGy. The isolate was gram-positive, non-motile coccus and catalase-positive. n culture, the red-pigmented smooth colony was observed. The biochemical test in API (analytical profile index) system showed that the isolate fermented glucose and fructose as the carbon source. Therefore, a radiation-resistant bacterium isolated from laver was potentially identified as Micrococcus roseus sp.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.289-295
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• 2010

The bacterium Deinococcus radiodurans is one of the most resistant organisms to the effects of ionizing radiation and other DNA-damaging agents. In this study, distributions of 10 ddr (DNA damage response) genes were investigated in 8 species of Deinococcus by polymerase chain reaction (PCR). We have compared the sequences of ddr genes of D. radiodurans, D. geothermalis and D. deserti, and selected primers which are suitable for the detection of ddr in different species of Deinococcus. A sequence homology search and PCR assay showed that ddrO, which encodes a global regulator of the radiation-desiccation response, was most well conserved in the Deinococcus lineage.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.248-251
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• 2013

The purpose of this study was to investigate the inactivation effect of intense pulsed light (IPL) on Micrococcus roseus, an irradiation-resistant bacterium isolated from laver, and the commercial feasibility of this sterilization method on dried laver. The inactivation of M. roseus in cultivated plates increased with increasing light intensity and treatment time. Approximately 6.6 log CFU/mL reduction of the cell viability was achieved with IPL treatment for 3 min at 1,000 V of light intensity, tailing was not shown. In addition, the inactivation rate of M. roseus increased with increasing pulse number at same light intensity and treatment time. The killing efficiency for M. roseus increased with by decreasing the distance between the light source and the sample surface.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.297-303
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• 1989

Attempts to isolate the naturally occurring ultra-violet resistant bacteria from environmental sources were made. The isolates, designated No.29, 100, and 107, among numbers of bacterial isolates revealed a remarkable resistance to UV ray, whose degree of resistance in dose/response kinetics was comparable to that of an endospore-former, Bacillus subtilis. In a range of 100-300 $Jm^{-2}$/min of UV irradiation, the isolates exhibited 500-1000 fold resistance compated with E. coli. The isolated appeared to possiss cell-bound pigment of organge or crimson-red. The isolate 29 is spherical in pairs or tetrads, whereas the isolates 100 and 107 are rod. All are Gram-gositive bacteria and seemed to be non-endospore-bearer. A number of biochemical studies pursued on the isolates suggested that they are quite different to each other. Electron microscopic examination and the physiological characters of the isolate 29 suggested that this UV resistant spherical bacterium might be one species of Deinococcus, probably Deinococus radiophilus. Since there is no documents on UV resistant, Gram-positive, non-sporeformer bacillus so far, the isolates 100 and 107 might be turned out as new kinds of UV resistant bacteria occurring in nature by further investigation.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.84-86
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• 2018

Cells of Deinococcus puniceus $DY1^T$ are Gram-positive, coccus-shaped, and crimson color-pigmented. Strain $DY1^T$ was isolated from soil irradiated with 5 kGy gamma radiation and showed resistance to UVC and gamma radiation. In this study, we report the complete genome sequence of a bacterium Deinococcus puniceus $DY1^T$ is consist of circular chromosome comprised of 2,971,983 bp, with the G + C content of 62.5%. The complete genome sequence was obtained using the PacBio RS II platform, it included 2,617 coding sequences (CDs), 2,762 genes, and 88 pseudogene.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.87-89
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• 2018

Flavisolibacter tropicus $LCS9^T$ was isolated from a soil sample collected from tropical zone within the Ecorium of the National Institute of Ecology in Seocheon, central-western Korea. In this study, we report the complete genome sequence of the bacterium Flavisolibacter tropicus $LCS9^T$, which possesses a circular chromosome comprised of 5, 940,863 bp with the G + C mol content of 41.5%. The genome sequence annotation showed that the complete genome includes 5,075 genes, 337 pseudogenes, and 59 rRNA genes. The radiation resistance genes such as excinuclease UvrABC complex and UvdE were present in the genome.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.574-581
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• 2011

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a fullsystem understanding of the radiation stress protection mechanisms of bacteria in different environments.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1637-1646
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• 2010

The bacterium Deinococcus radiodurans is one of the most resistant organisms to ionizing radiation and other DNA-damaging agents. Although, at present, 30 Deinococcus species have been identified, the whole-genome sequences of most species remain unknown, with the exception of D. radiodurans (DRD), D. geothermalis, and D. deserti. In this study, comparative genomic hybridization (CGH) microarray analysis of three Deinococcus species, D. radiopugnans (DRP), D. proteolyticus (DPL), and D. radiophilus (DRPH), was performed using oligonucleotide arrays based on DRD. Approximately 28%, 14%, and 15% of 3,128 open reading frames (ORFs) of DRD were absent in the genomes of DRP, DPL, and DRPH, respectively. In addition, 162 DRD ORFs were absent in all three species. The absence of 17 randomly selected ORFs was confirmed by a Southern blot. Functional classification showed that the absent genes spanned a variety of functional categories: some genes involved in amino acid biosynthesis, cell envelope, cellular processes, central intermediary metabolism, and DNA metabolism were not present in any of the three deinococcal species tested. Finally, comparative genomic data showed that 120 genes were Deinococcus-specific, not the 230 reported previously. Specifically, ddrD, ddrO, and ddrH genes, previously identified as Deinococcus-specific, were not present in DRP, DPL, or DRPH, suggesting that only a portion of ddr genes are shared by all members of the genus Deinococcus.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.308-312
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• 2010

Deinococcus geothermalis is a moderate thermophillic radiation resistant bacterium producing greater abundance of sugar metabolism enzymes than other Deinococcus species. In this study, optimal condition for xylanolytic activity of D. geothermalis was determined and xylooligosaccharides from oat spelt, beechwood, and birchwood xylan hydrolysates by this organism were analyzed through HPLC. Reducing sugar yield was increased in the order of beechwood, birchwood, and oat spelt xylan. D. geothermalis displayed maximal xylanolytic activity at $40^{\circ}C$ and pH 8.0. Magnesium ion increased xylanolytic activity upto 7.5 fold. Six kinds of xylooligosaccharides (xylose, xylobios, xylotriose, xylotetraose, xylopentaose, and xylohexalose) were detected from beechwood and birchwood xylan reaction products. Among them, xylose was the major product. However, only three kinds of xylooligosaccharides (xylose, xylopentaose, and xylohexalose) were clearly detected from oat spelt xylan. Gamma-ray (50 kGy) treatment of beechwood xylan, birchwood xylan and oat spelt xylan increased xylanolytic activity of D. geothermalis. The results indicate that D. geothermalis and pretreatment of radiation is useful for xylooligosaccharides production.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.169-177
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• 2008

Global gene expression of Deinococcus radiodurans, a highly radiation resistant bacterium, in response to excess copper was analyzed by using oligonucleotide microarray chip. Among 3,187 open reading frames of D. radiodurans, seventy genes showed a statistically significant expression ratio of at least 2-fold changes under growth conditions of excess copper; 64 genes were induced and 6 genes were reduced. Especially, two operons ($DRB0014{\sim}DRB0017$ and $DRB0125{\sim}DRB0121$) presumably involved in the iron transport and utilization were the most highly induced genes by excess copper. A quantitative real-time PCR assay revealed that DRB00l4 and DRB0125 are highly transcribed responding to excess copper and 2,2'-dipyridyl, an iron chelator. In addition, the transcription of both genes was not changed by excess iron and bathocuproine disulphonate, a copper chelator. These results suggested that the copper metabolism may be closely connected with the iron transport and utilization in D. radiodurans. However, the disruption of each gene, DRB00l4 and DRB0125, did not affect the copper and radiation resistance, the most well-known character of this organism.