• Proceedings of the Korea Society of Environmental Biology Conference
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• 2005.12a
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• pp.86-86
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• 2005

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.205-211
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• 2004

A 16S rDNA clone library was generated to investigate the bacterial diversity in tidal flat sediment in Ganghwa Island, Republic of Korea. A total of 103 clones were sequenced and analyzed by comprehensive phylogenetic analyses. No clones were identical to any of known 16S rRNA sequences in public databases. Sequenced clones fell into thirteen lineages of the domain Bacteria: the alpha, beta, gamma, delta, and epsilon Proteobacteria, Actinobacteria, CFB group, Chloroflexi, Acidobacteria, Planctomycetes, Verrucomicrobia, and known uncultured candidate divisions (OP11, BRC1, KSB1, and WS1). Two clones were not associated with any known bacterial divisions. The majority of clones belonged to the gamma and delta Proteobacteria (46.7%). Clones of Actinobacteria were distantly related to known taxa. It is evident from 16S rDNA-based community analysis that the bacterial community in tidal flat sediment is remarkably diverse and unique among other marine environments examined so far.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.147-154
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• 2014

Bacteria play an important role in biogeochemical cycles in marine environments and their functional attributes in ecosystems depend primarily on species composition. In this study, seasonal variation of bacterial diversity was investigated by pyrosequencing of 16S rDNA in surface sediment and overlying seawater collected in the south East Sea, planned for the site of $CO_2$ sequestration by the carbon capture and storage (CCS) project. Gammaproteobacteria was dominant in the sediment in most seasons, whereas Alphaproteobacteria was a most dominant group in the overlying water. Thus, the bacterial diversity greatly differ between sediment and seawater samples. On the genus level, bacterial diversity between two habitats was also different. However, the number of genera found over 5% were less than 10 in both habitats and the bacterial community was composed of a number of diverse minor or rare genera. Elevation of $CO_2$ concentration during a $CO_2$ storage process, could result in change of bacterial diversity. Thus, this study will be very useful to access the effect of $CO_2$ on bacterial diversity and to predict functional change of the ecosystem during the process of CCS project.

• Environmental Engineering Research
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• v.21 no.1
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• pp.52-57
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• 2016

Sediment is a useful natural source but deteriorated continually by anthropogenic and industrial sources. Therefore, it is imperative to search a suitable method for improving or restoring sediment quality. Sediment has been tested to identify the effects of some external agents on a polluted area for 28 days. Chemical analysis and total viable counts (TVC) test have been conducted for 4 days interval to assess their performance. The analyses of chemical oxygen demand (COD), acid volatile sulfide (AVS), total phosphorous (T-P), total nitrogen (T-N) indicate that the chemical agents was more efficient to improve sediment quality whereas the microbial agent was more efficient for nutrient releasing from sediment. Oxygen releasing property of the chemical agent was thought to be providing with more congenial environment for the higher growth of the bacterial community than the direct application of microbial agents.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.366-374
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• 2010

Culture-dependent RFLP and culture-independent DGGE were employed to investigate the bacterial community associated with the marine sponge Spirastrella abata. A total of 164 bacterial strains associated with the sponge were cultivated using Zobell and Natural sea salt media. PCR amplicons of the 16S rDNA from the bacterial strains were digested with the restriction enzymes HaeIII and MspI, and then assigned into different groups according to their restriction patterns. The 16S rDNA sequences derived from RFLP patterns showed more than 95% similarities compared with known bacterial species, and the isolates belonged to four phyla, Proteobacteria (Alphaproteobacteria, Gammaproteobacteria), Actinobacteria, Firmicutes, and Bacteriodetes, of which Alphaproteobacteria was dominant. DGGE fingerprinting of 16S rDNAs amplified from the sponge- derived total gDNA showed five major DGGE bands, and their sequences showed more than 96% similarities compared with available sequences. The sequences derived from DGGE bands revealed high similarity with the uncultured bacterial clones. DGGE revealed that bacterial community consisted of four phyla, including Proteobacteria (Alphaproteobacteria, Gammaproteobacteria), Actinobacteria, Spirochetes, and Chloroflexi. Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria were commonly found in bacteria associated with S. abata by both RFLP and DGGE methods; however, overall bacterial community in the sponge differed depending on the analysis methods.

• Journal of Microbiology
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• v.43 no.2
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• pp.144-151
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• 2005

During the past ten years, Archaea have been recognized as a widespread and significant component of marine picoplankton assemblages. More recently, the presence of novel archaeal phylogenetic lineages has been discovered in coastal marine environments, freshwater lakes, polar seas, and deep-sea hydrothermal vents. Therefore, we conducted an investigation into the archaeal community existing in tidal flat sediment collected from Ganghwa Island, Korea. Phylogenetic analysis of archaeal 16S rDNA amplified directly from tidal flat sediment DNA revealed the presence of two major lineages, belonging to the Crenarchaeota ($53.9\%$) and Euryarchaeota ($46.1\%$) phyla. A total of 102 clones were then sequenced and analyzed by comprehensive phylogenetic analysis. The sequences determined in our samples were found to be closely related to the sequences of clones which had been previously obtained from a variety of marine environments. Archaeal clones exhibited higher similarities ($83.25 - 100\%$) to sequences..from other environments in the public database than did those ($75.22 - 98.46\%$) of previously reported bacterial clones obtained from tidal flat sediment. The results of our study suggest that the archaeal community in tidal flat sediment is remarkably diverse.

• Journal of Life Science
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• v.28 no.8
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• pp.955-961
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• 2018

Although much research has focused on various bioactive substances in starfish, research on microorganisms isolated from starfish is lacking as compared with other natural products. In this study, we investigated bacterial communities in the gut of red starfish (Certonardoa semiregularis) in Jeju Island. In total, 103 bacterial strains were isolated using marine agar and R2A medium. The isolated strains were analyzed and identified using the 16S rRNA gene sequence. Based on an analysis of this gene sequence, the 103 isolated bacteria were classified into four major groups: Proteobacteria (93%: Alpha-proteobacteria, 24.8%; Beta-proteobacteria, 4%; Gammaproteobacteria, 65%) Bacteroidetes (4%), Actinobacteria (2%), and Firmicutes (1%). In addition, the isolates were divided into seven classes (Actinobacteria, Flavobacteria, Bacilli, Sphingobacteria, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria), 15 orders, 19 families, and 24 genera. A phylogenetic analysis revealed two strains, Lysobacter sp. and Pedobacter sp., with similarity of 97.55% and 97.58%, respectively. As the similarity in the 16S rRNA gene sequence was 98% or less compared to previously identified bacteria, the two strains may possibly be classified as a new genus or species. We suggest that additional studies, including biochemical and morphological tests, should be performed to identify the new candidate strains.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.101.2-101
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• 1999

No Abstract, See Full Text

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.76-83
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• 2014

Bacteria associated with marine sponges seemed to be concerned in halogenation/dehalogenation process of natural compounds. In the present study, the effect of hexabromobenzene (HBB) on the community structure of bacteria associated with a marine sponge Axinella sp. from Chuuk State under anaerobic condition was investigated. Regardless of 100 ppm HBB, most of detected microorganisms displayed high similarity with clones reported from coral or sponges. Amongst, Desulfovibrio marinisediminis like clones were dominant. Clones affiliated with Lentisphaerae and Fusibacter paucivorans (Clostridia) were detected at the conditions without HBB but clones affiliated with Vallitalea guaymasensis (Clostridia) increased its proportion with HBB. From these results and previous reports clones affiliated with D. marinisediminis and V. guaymasensis seemed to be concerned in halogenation/dehalogenation process.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.376-380
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• 2014

Marine beach sands with bacterial pathogens may cause increased outcomes of illness among beachgoers in summer. In this study, pyrosequencing of 16S ribosomal DNAs extracted from 12 beach sands was performed to understand how the environmental factors of wastewaters or human wastes affected the distribution of bacterial communities at the beach of North Gyeongsang province (Yeongdeok and Pohang counties) in the middle of October. It was found that Acidobacteria were dominantly distributed in the sands near the clean seawaters, Proteobacteria in the sands near the river waters, Cyanobacteria in the sands near the wastewaters, and Bacteroidetes in the sands near the beach park. Other phyla groups such as Actinobacteria, Chlorobi, Deferribacteres, Deinococcus-thermus, Firmicutes, Gemmatimonadetes, Nitrospirae, and/or Verrucomicrobia were distributed at low relative abundance (1-5%).