• Title/Summary/Keyword: extinction dilution culture

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Genome sequence of carotenoid producing Sphingobacteriaceae bacterium SH-48 isolated from freshwater in Korea (카로티노이드 생산 Sphingobacteriaceae SH-48 균주의 유전체 염기서열 분석)

  • Choi, Ahyoung;Chung, Eu Jin;Nam, Young Ho;Choi, Gang-Guk
    • Korean Journal of Microbiology
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    • v.53 no.4
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    • pp.347-350
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    • 2017
  • We sequenced the genome of the Sphingobacteriaceae bacterium SH-48 isolated from the Sohan stream in Republic of Korea by using a dilution-to-extinction culturing method. The sequences were assembled into a draft genome containing 5,650,162 bp with a G + C content of 35.4% and 4,856 protein-coding genes in 2 contigs. This strain contains the carotenoid biosynthesis genes crtY, crtZ, crtD, crtI, crtB, and crtH as gene clusters. This genomic information provides new insights into the carotenoid biosynthesis pathway.

Identification of Anaerobic Thermophilic Thermococcus Dominant in Enrichment Cultures from a Hydrothermal Vent Sediment of Tofua Arc (Tofua Arc의 열수구환경으로부터 호열성 혐기성 고세균(Thermococcus)의 농화배양 및 동정)

  • Cha, In-Tae;Kim, So-Jeong;Kim, Jong-Geol;Park, Soo-Je;Jung, Man-Young;Ju, Se-Jong;Kwon, Kae-Kyoung;Rhee, Sung-Keun
    • Korean Journal of Microbiology
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    • v.48 no.1
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    • pp.42-47
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    • 2012
  • Hydrothermal vents (HTV) provide special environments for evolution of lives independent on solar energy. HTV samples were gained from Tofua arc trench in Tonga, South Pacific. We investigated archaeal diversity enriched using combinations of various electron donors (yeast extract and $H_2$) and electron acceptors [Iron (III), elemental sulfur ($S^0$) and nitrate. PCR amplification was performed to detect archaeal 16S rRNA genes after the cultures were incubated $65^{\circ}C$ and $80^{\circ}C$ for 2 weeks. The cultures showing archaeal growth were transferred using the dilution-to-extinction method. 16S rRNA gene PCR-Denaturing Gradient Gel Electrophoresis was used to identify the enriched archaea in the highest dilutions where archaeal growth was observed. Most of cultured archaea belonged to genus of Thermococcus (T. alcaliphilius, T. litoralis, T. celer, T. barossii, T. thoreducens, T. coalescens) with 98-99% 16S rRNA gene similarities. Interestingly, archaeal growth was observed in the cultures with Iron (III) and nitrate as an electron acceptor. It was supposed that archaea might use the elemental sulfur generated from oxidation of the reducing agent, sulfide. To cultivate diverse archaea excluding Thermococcus, it would be required to use other reducing agents instead of sulfide.

Complete genome sequence of Betaproteobacteria strain GR16-43 isolated form a freshwater pond in South Korea (담수에서 분리한 Betaproteobacteria GR16-43의 유전체 염기서열 분석)

  • Choi, Ahyoung;Baek, Kiwoon;Chung, Eu Jin;Kim, Jee-Hwan;Choi, Gang-Guk
    • Korean Journal of Microbiology
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    • v.53 no.4
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    • pp.320-322
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    • 2017
  • A betaproteobacterium strain GR16-43 was isolated from a surface layer of the Geomnyong Pond in Republic of Korea by a dilution-to-extinction culturing method. We report the whole genome sequence of the strain GR16-43, which contains 4,806,848 bp with a G + C content 67.12%, and to include 4,424 protein-coding genes and 47 transfer RNA genes. The genome was determined to contain the genes encoding carbon monoxide dehydrogenase, nitrate reductase, nitrite reductase, nitric oxide reductase, and the sulfur oxidation (sox) gene cluster, highlighting the potential importance of the bacterial group represented by the strain in the cycling of inorganic elements. These results indicate that strain GR16-43 genome showed several traits indicating adaptation of the bacteria to living in freshwater environments.