Mechanism of lipid-body formation in prokaryotes: how bacteria fatten up

Mol Microbiol. 2005 Feb;55(3):750-63. doi: 10.1111/j.1365-2958.2004.04441.x.


Neutral lipid accumulation is frequently observed in some Gram-negative prokaryotes like Acinetobacter sp. and most actinomycetes, including the pathogenic Mycobacterium tuberculosis and antibiotic producing streptomycetes. We examined the formation of wax ester- and triacylglycerol (TAG)-bodies in Acinetobacter calcoaceticus and Rhodococcus opacus using microscopic, immunological and biophysical methods. A general model for prokaryotic lipid-body formation is proposed, clearly differing from the current models for the formation of lipid inclusions in eukaryotes and of poly(hydroxyalkanoic acid) (PHA) inclusions in prokaryotes. Formation of lipid-bodies starts with the docking of wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT) to the cytoplasm membrane. Both, analyses of in vivo and in vitro lipid-body synthesis, demonstrated the formation of small lipid droplets (SLDs), which remain bound to the membrane-associated enzyme. SLDs conglomerated subsequently to membrane-bound lipid-prebodies which are then released into the cytoplasm. The formation of matured lipid-bodies in the cytoplasm occurred by means of coalescence of SLDs inside the lipid prebodies, which are surrounded by a half-unit membrane of phospholipids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter calcoaceticus / growth & development
  • Acinetobacter calcoaceticus / metabolism*
  • Acyltransferases / metabolism*
  • Cell Membrane / enzymology
  • Cytoplasm / metabolism
  • Esters / metabolism
  • Inclusion Bodies / metabolism*
  • Lipid Metabolism*
  • Microscopy, Confocal
  • Microscopy, Electron
  • Rhodococcus / growth & development
  • Rhodococcus / metabolism*
  • Triglycerides / metabolism
  • Waxes / metabolism


  • Esters
  • Triglycerides
  • Waxes
  • Acyltransferases
  • long-chain-alcohol O-fatty-acyltransferase