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Bdellovibrio-and-like organisms (BALO) are a phylogenetically diverse group of predatory prokaryotes that consists of the two families Bdellovibrionaceae and Bacteriovoracaceae. We investigated the phospholipid composition of the three important BALO strains Bacteriovorax stolpii (DSM 12778), Bdellovibrio bacteriovorus HD100 (DSM 50701) and Peredibacter starrii (DSM 17039). We confirmed the presence of sphingophosphonolipids in B. stolpii, while we characterized sphingophosphonolipids with a 2-amino-3-phosphonopropanate head group for the first time. In B. bacteriovorus HD100 phosphatidylthreonines were found and, thus, B. bacteriovorus is the second prokaryote investigated so far possessing this rare lipid class. In the third analyzed organism, P. starrii, we observed phosphatidylethanolamine structures with an additional N-glutamyl residue, which form the first reported class of amino acid-containing phosphatidylethanolamines.

Bdellovibrionales is a phylogenetically diverse group of predatory prokaryotes, which consists of the two families Bdellovibrionaceae and Bacteriovoracaceae. We describe LPS and lipid A of the type strain Bacteriovorax stolpii DSM 12778, representing the first characterized endotoxin of a Bacteriovoracaceae member. It has a smooth form LPS, which was identified by SDS-polyacrylamide gel electrophoresis. The lipid A structure was determined by combined gas chromatography-mass spectrometry, electrospray ionization mass spectrometry and NMR spectroscopy. Its backbone consists of two beta-(1-->6)-linked 2,3-diamino-2,3-dideoxy-D-glucopyranoses (GlcpN3N) carrying a pyrophosphoethanolamine at O-4' of the non-reducing sugar and a phosphate group linked to O-1 of the reducing GlcpN3N. Positions 2, 3, 2' and 3' of the two GlcpN3N are acylated with primary 3-hydroxy fatty acids and one of those carries a secondary fatty acid.