Characterization of extracellular DNA production and flocculation of the marine photosynthetic bacterium Rhodovulum sulfidophilum

Hiromichi Suzuki, Masahide Daimon, Tomoyuki Awano, So Umekage, Terumichi Tanaka, Yo Kikuchi

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The marine photosynthetic bacterium Rhodovulum sulfidophilum produces extracellular nucleic acids involved in its flocculation. Previously, we showed that the RNA fraction of these extracellular nucleic acids released into the culture medium contains mainly non-aminoacylated fully mature-sized tRNAs and fragments of 16S and 23S rRNAs. Here, we report the characterization of extracellular DNA itself and its production during cultivation. No differences were detected in nucleotide sequence between the intracellular DNA and extracellular soluble DNA on Southern blotting. Whole intracellular DNA seemed to be released from the cell. The bacterial floc was degraded by deoxyribonuclease or ribonuclease treatment, indicating that at least the extracellular DNA and RNAs in the floc are involved in the maintenance of the floc. When cultivated in nutritionally rich medium, the bacteria formed small flocs and produced large amounts of extracellular DNA, which were solubilized in the medium. In nutritionally poor medium, however, huge flocs of cells appeared and almost no extracellular soluble DNA was observed in the medium. As the floc was degraded by deoxyribonuclease treatment, it seems likely that the extracellular soluble DNA observed in the rich medium may be incorporated into the large floc and play a role in floc maintenance in poor medium. Addition of an inhibitor of quorum sensing, α-cyclodextrin, inhibited huge floc maintenance in the nutritionally poor medium. In the presence of α-cyclodextrin, the floc was rapidly degraded and extracellular soluble DNA production increased.

Original languageEnglish
Pages (from-to)349-356
Number of pages8
JournalApplied Microbiology and Biotechnology
Volume84
Issue number2
DOIs
Publication statusPublished - 2009 Aug
Externally publishedYes

Fingerprint

Rhodovulum
Flocculation
Bacteria
DNA
Deoxyribonucleases
Maintenance
Cyclodextrins
Nucleic Acids
RNA
Quorum Sensing
Ribonucleases
Southern Blotting
Transfer RNA
Culture Media

Keywords

  • α-cyclodextrin
  • Extracellular DNA
  • Extracellular RNA
  • Floc
  • Photosynthetic bacteria
  • Quorumsensing

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology

Cite this

Characterization of extracellular DNA production and flocculation of the marine photosynthetic bacterium Rhodovulum sulfidophilum. / Suzuki, Hiromichi; Daimon, Masahide; Awano, Tomoyuki; Umekage, So; Tanaka, Terumichi; Kikuchi, Yo.

In: Applied Microbiology and Biotechnology, Vol. 84, No. 2, 08.2009, p. 349-356.

Research output: Contribution to journalArticle

Suzuki, Hiromichi ; Daimon, Masahide ; Awano, Tomoyuki ; Umekage, So ; Tanaka, Terumichi ; Kikuchi, Yo. / Characterization of extracellular DNA production and flocculation of the marine photosynthetic bacterium Rhodovulum sulfidophilum. In: Applied Microbiology and Biotechnology. 2009 ; Vol. 84, No. 2. pp. 349-356.
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