Analysis of polar lipids from some representative enterobacteria, Plesiomonas and Acinetobacter by fast atom bombardment‐mass spectrometry

Abstract

Fast atom bombardment-mass spectrometry (FAB-MS) was used to analyse lipid extracts of bacteria to assess its usefulness for analysing anionic phospholipids of potential chemotaxonomic value. The following micro-organisms were tested: Acinetobacter calcoaceticus, Acinetobacter sp., Citrobacter freundii, Enterobacter cloacae (2 strains), Escherichia coli (3 strains), Hafnia alvei, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Plesiomonas shigelloides, Proteus mirabilis (3 strains), Serratia liquefaciens and Serratia marcescens. Negative-ion spectra provide data for twenty-seven major carboxylate anions (m/z 209-325) and for thirty-seven major phospholipid anions (m/z 645-774). Generally, the largest carboxylate peaks were due to 16:1, 16:0, cyc17 and 18:1 while the largest phospholipid anion peaks were due to PE(32:1), PE(33:1), PE(34:1), PE(34:2), PG(30:2), PG(31:2), PG(32:2), PG(34:1) and PS(33:0). However, quantitative differences were observed. For example, Acinetobacter lacked PE (33:1) but had exceptionally high peaks at m/z 748, PS(33:0), and m/z 281, octadecanoate. Unknown 'carboxylate' peaks were detected at m/z 254, 256, 261, 268, 282 and 301. In some cases, unknown peaks appeared to constitute possible homologous series being separated by delta m/z of 14(identical to methylene). For chemotaxonomic purposes, the complexity of the data required numerical analysis. Using the Pearson coefficient of linear correlation, as a measure of association, it was possible to compare all strains analysed. Typical results for strain comparisons were as follows: Ent. cloacae vs Ent. cloacae, r = 0.90 (Ent. cloacae vs Ac. calcoaceticus, r = 0.46). Thus FAB-MS represents an excellent means of obtaining large quantities of data on polar lipids of a range of bacterial isolates, which may be suitable for chemotaxonomic purposes.

Phospholipid molecular species distribution of some medically important Candida species analysed by fast atom bombardment mass spectroscopy

“…1996). Similarly, in E. coli , PE and PG equally favour a single unsaturation in subsitutent fatty acids (Aluyi et al . 1992) so that PE(34 : 1) and PG(34 : 1) are both major constituents of spectra.…”

“…Chemosystematic methods have been widely used for bacterial identification and classification (Drucker 1981 ;Goodfellow and Minnikin 1985) and mass spectrometry has proved useful in many chemotaxonomic studies (Aluyi and Drucker 1979 ;Tavakkol et al 1985 ;Drucker and Jenkins 1989). Recently fast atom bombardment mass spectrometry (FAB MS) has been introduced to microbial chemotaxonomy (Heller et al 1987 ;Aluyi et al 1992 ;Drucker et al 1993 ;Drucker 1994 ;Drucker and Abdullah 1995 ;Drucker et al 1996 ;Drucker 1997). This method allows novel information on polar lipid (POL) molecular species distribution to be gained very readily.…”

“…Recently fast atom bombardment mass spectrometry (FAB MS) has been introduced to microbial chemotaxonomy (Heller et al . 1987 ; Aluyi et al . 1992 ; Drucker et al .…”

Phospholipid molecular species distribution of oralPrevotella corporisclinical isolates

“…Extraction of lipids has been described elsewhere [18, 19]. Analar reagents were used throughout and all the detergent‐washed glassware was rinsed in chloroform/methanol (1:2 v/v), to ensure the removal of hydrophobic contaminants.…”

Phospholipid molecular species distribution of oral Prevotella corporis clinical isolates

“…Extraction of lipids has been described elsewhere [18,19]. Analar reagents were used throughout and all the detergent-washed glassware was rinsed in chloroform/methanol (1:2 v/v), to ensure the removal of hydrophobic contaminants.…”