Widespread abundance of functional bacterial amyloid in mycolata and other gram-positive bacteria.


Journal Article

Until recently, extracellular functional bacterial amyloid (FuBA) has been detected and characterized in only a few bacterial species, including Escherichia coli, Salmonella, and the gram-positive organism Streptomyces coelicolor. Here we probed gram-positive bacteria with conformationally specific antibodies and revealed the existence of FuBA in 12 of 14 examined mycolata species, as well as six other distantly related species examined belonging to the phyla Actinobacteria and Firmicutes. Most of the bacteria produced extracellular fimbriae, sometimes copious amounts of them, and in two cases large extracellular fibrils were also produced. In three cases, FuBA was revealed only after extensive removal of extracellular material by saponification, indicating that there is integrated attachment within the cellular envelope. Spores of species in the genera Streptomyces, Bacillus, and Nocardia were all coated with amyloids. FuBA was purified from Gordonia amarae (from the cell envelope) and Geodermatophilus obscurus, and they had the morphology, tinctorial properties, and beta-rich structure typical of amyloid. The presence of approximately 9-nm-wide amyloids in the cell envelope of G. amarae was visualized by transmission electron microscopy analysis. We conclude that amyloid is widespread among gram-positive bacteria and may in many species constitute a hitherto overlooked integral part of the spore and the cellular envelope.

Full Text

Cited Authors

  • Jordal, PB; Dueholm, MS; Larsen, P; Petersen, SV; Enghild, JJ; Christiansen, G; Højrup, P; Nielsen, PH; Otzen, DE

Published Date

  • June 2009

Published In

Volume / Issue

  • 75 / 12

Start / End Page

  • 4101 - 4110

PubMed ID

  • 19395568

Pubmed Central ID

  • 19395568

Electronic International Standard Serial Number (EISSN)

  • 1098-5336

International Standard Serial Number (ISSN)

  • 0099-2240

Digital Object Identifier (DOI)

  • 10.1128/AEM.02107-08


  • eng