Analysis of the phase-variable regulation of the capsular polysaccharides in the human symbiont Bacteroides

2011 Fiscal Year Final Research Report

• Project/Area Number: 22790409
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Bacteriology (including Mycology)
• Research Institution: The University of Tokushima
• Principal Investigator: NAKAYAMA Haruyuki 徳島大学, 大学院・ヘルスバイオサイエンス研究部, 助教 (80294669)
• Project Period (FY): 2010 – 2011
• Keywords: Bacteroides fragilis / 莢膜 / 相変異 / 腸管共生 / DNA逆位 / 腸管免疫 / 腸管常在菌 / T細胞分化

Research Abstract

Bacteroides fragilis strain YCH46 possesses master DNA invertases that regulate DNA inversions at multiple loci simultaneously. One is Mpi that mediates the on-off switching of seven promoter regions for capsular polysaccharide(PS) biosynthesis. Dispite the importance of PS synthesis for intestinal colonization, little is known about PS regulation in vitro and in vivo. While this organism may theoretically display up to 128 distinct polysaccharide combinations, the PS3 promoter was only on in greater than 12% of bacteria grown in vitro. Intestinal lamina propria lymphocytes from PS3-deleted B. fragilis mono-associated mice displayed decreased percentages of CD4^+ IL-4^+ T cells compared with control mice.

Research Products

• [Journal Article] Characterization of a gene cluster for sialoglycoconjugate utilization in Bacteroides fragilis (2012)
  • Author(s): Nakayama-Imaohji H, Ichimura M, Iwasa T, Okada N, Ohnishi Y, Kuwahara T
  • Journal Title: J Med Invest Volume: 59(1-2) Pages: 79-94
  • Peer Reviewed
• [Journal Article] The lifestyle of the segmented filamentous bacterium : a nonculturable gut-associated immunestimulating microbe inferred by whole-genome sequencing (2011)
  • Author(s): Kuwahara T, Ogura Y, Oshima K, Kurokawa K, Hirakawa H, Ooka T, Itoh T, Nakayama-Imaohji H, Ichimura M, Itoh K, Ishifune C, Maekawa Y, Yasutomo K, Hattori M, Hayashi T
  • Journal Title: DNA Res Volume: 18(4) Pages: 291-303
  • Peer Reviewed
• [Journal Article] Utilization of titanium oxide-like compound as an inorganic phosphate adsorbent for the control of serum phosphate level in chronic renal failure (2010)
  • Author(s): Tamagawa K, Nakayama-Imaohji H, Wakimoto S, Ichimura M, Kuwahara T
  • Journal Title: J Med Invest Volume: 57(3-4) Pages: 275-83
  • Peer Reviewed
• [Journal Article] Efficient electrotransformation of Bacteroides fragilis (2010)
  • Author(s): Ichimura M, Nakayama-Imaohji H, Wakimoto S, Morita H, Hayashi T, Kuwahara T
  • Journal Title: Appl Environ Microbiol Volume: 76(10) Pages: 3325-32
  • Peer Reviewed
• [Presentation] Dynamic regulation of the DNA inversions in susC/ susD genes clusters by a single tyrosine site-specific recombinase in Bacteroides fragilis. IUMS 2011 Congress (2011)
  • Author(s): Nakayama-Imaohji H, Kuwahara T, Ichimura M and Yasutomo K
  • Organizer: 13^<th> International Congress of Bacteriology and Applied Microbiology
  • Place of Presentation: Sapporo
  • Year and Date: 20110905-10
• [Presentation] Efficient electrotransformation strageties of Bacteroides fragilis. IUMS 2011 Congress (2011)
  • Author(s): Ichimura M, Kuwahara T, Nakayama-Imaohji H and Yasutomo K
  • Organizer: IUMS 2011 Congress, 13^<th> International Congress of Bacteriology and Applied Microbiology
  • Place of Presentation: Sapporo
  • Year and Date: 20110905-10