A New Glycosylated Lipopeptide Incorporated into the Cell Wall of a Smooth Variant of Gordona hydrophobica

Abstract

A cell wall component of a smooth variant of Gordona hydrophobica 1775/15 was isolated and purified, and its structure was determined by various chemical methods, including chemical synthesis of part structures, Edman degradation, gas chromatography/mass spectrometry analysis, matrix-assisted laser desorption ionizationpost-source decay (MALDI-PSD) tandem mass spectrometry, and 1 H and 13 C NMR using one-and two-dimensional, homo-and heteronuclear correlated spectroscopy. The cell wall component was found to be a (mono-) glycosylated peptidolipid (GPL) consisting of a tridecapeptide interlinked by a ␤-hydroxylated fatty acid (3-hydroxyeicosanoic acid, 20:0 (3-OH)) to form a cyclic lactone ring structure. The main fraction of GPL, for which we propose the name gordonin, was identified as In contrast, rough variants of G. hydrophobica 1775/15 lack these peptidolipids or synthesize them to a much lesser extent indicating that gordonin contributes significantly to the physicochemical character of the cell surface.Biofiltration is the method of choice for the treatment of waste gases with high volumes and low concentrations of organic pollutants. This technology requires low investment and operation costs and guarantees high reliability. Although biofiltration is already widely used, knowledge about the biology underlying this technology is lacking. Only a few studies have so far been conducted on the microorganisms involved in the process of exhaust-air treatment. Recently, Bendinger et al.(1) isolated coryneform bacteria from a biofilter that was loaded with the waste gas from an animal-rendering plant. On the basis of chemotaxonomic differentiation they were able to identify strains of the genus Corynebacterium, Gordona, Mycobacterium, and Arthrobacter. Some biofilter isolates of Gordona hydrophobica (2) showed colony morphologies, which gave rise to different physicochemical properties of their cell surface. The rough variants possess an extremely hydrophobic cell surface due to a hydrophobic mycolic acid layer. In contrast, the smooth variants exhibit a hydrophilic to moderate hydrophobic surface (3), although they are also surrounded by a hydrophobic mycolic acid layer. Obviously, the smooth ones incorporate into their cell wall an additional surface component, which exposes its hydrophilic part toward the medium. The observation that rough colonies of Gordona only gave rise to rough colonies whereas smooth colonies gave rise to smooth as well as rough ones when grown on complex media indicated that the rough variants lost the ability to cover their extremely hydrophobic surface with a more hydrophilic compound.A similar change in colony morphology was reported for mycobacterial species that are closely related to the genus Gordona. Camphausen et al. (4) found a trehalose containing lipooligosaccharide to be responsible for the observed change in Mycobacterium paratuberculosis. Fregnan et al. (5) showed that smooth variants of an unclassified scotochromogenic Mycobacterium possessed a mycoside D that is absen...

Structural Determination of a New Peptidolipid Family from Rhodococcus opacus and the Pathogen Rhodococcus equi by Multiple Stage Mass Spectrometry

“…This cleavage of the C3­(OH)–C2 bond to eliminate a RCHO residue has been previously reported for glycopeptidolipid, and molecules possessing β-OH fatty acyl group such as mycolic acid and N-β-hydroxyacyl sphingosine (i.e., ceramide­[BS]) families . Peptidolipids containing β-OH eicosanoic acid substituent have been isolated from the cell wall of a smooth variant of Gordona hydrophobica previously …”

Surface-active compounds and their role in the access to hydrocarbons in Gordonia strains

“…Interestingly, the BS29 cells develop a hydrophilic surface during growth on hydrocarbons and, at the same time, they disperse, rendering the culture turbid. The hydrophilic surface may be due to surface amphiphiles that expose their hydrophilic portion toward the medium, masking the highly hydrophobic character of the mycolic acid layer, as previously described both in Corynebacterineae (Moormann et al , 1997; Sutcliff, 1998). Thus, Gordonia sp.…”

The cell surface-exposed glycopeptidolipids confer a selective advantage to the smooth variants ofMycobacterium smegmatis in vitro

“…3). The overproduction of an extracellular lipid has been similarly correlated with the smooth phenotypes of M. vaccae (Rodríguez‐Güell et al , 2006) or the related Gordona hydrophobica (Moormann et al , 1997). Interestingly, Mycobacterium canettii , which is the progenitor of the modern M. tuberculosis strains (Brosch et al , 2002), is smooth and produces phenolglycolipid (PGL‐tb) and LOS (Daffé et al , 1991), whereas H37Rv and related strains do not.…”