Inositol-phosphodihydroceramides in the periodontal pathogen Tannerella forsythia: Structural analysis and incorporation of exogenous myo-inositol.
Bottom Line: T. forsythia lacks the enzymatic machinery required for myo-inositol synthesis but was found to internalize inositol from the medium for the synthesis of both Tf GL1 and Tf GL2.Their synthesis could be reliant on an external source of myo-inositol.The effects of these unique lipids on the immune system and their role in bacterial virulence could be relevant in the search for new drug targets.
Affiliation: Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, 1190 Vienna, Austria.Show MeSH
Related in: MedlinePlus
Mentions: A BLASTP search against the proteome of T. forsythia ATCC 43037 did not identify proteins homologous to the two enzymes involved in inositol synthesis, i.e. inositol-3-phosphate synthase and inositolmonophosphatase. This suggests that T. forsythia utilizes exogenous myo-inositol for the synthesis of Tf GL1 and Tf GL2. In order to prove the uptake of the glycolipid precursor myo-inositol from the medium, T. forsythia was grown in the presence of [14C(U)] myo-inositol. Lipids were extracted using the Bligh–Dyer method and the organic phase was backwashed several times with water to insure complete removal of non-incorporated radiolabeled inositol from the organic phase. The latter fraction (containing about 0.2% of the radioactive precursor initially added) was spotted onto a HPTLC plate and separated using solvent system A. After a 3-week exposure time, two bands were clearly visible at the exact Rf values of 0.10 and 0.15 corresponding to Tf GL1 and Tf GL2, respectively (Fig. 7). This indicated that T. forsythia is able to import inositol from the medium and incorporate it into its lipids. No other bands were detected, indicating that [14C(U)] myo-inositol was solely incorporated into Tf GL1 and Tf GL2.
Affiliation: Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, 1190 Vienna, Austria.