Phospholipids of Lactobacillus spp

Abstract

Lactobacillus phospholipid molecular species were analyzed by mass spectrometry. Prominent anions were consistent with presence of the phosphatidylglycerols PG(37:2), PG(36:2), PG(35:1), PG(34:1), and PG(33:1). Diglycosyldiacylglycerol molecular species were also observed, although nitrogen-containing phospholipids were absent. An anion of m/z 759 was derived from an apparently novel type of lipid.Numerous studies have investigated the lipid composition of Lactobacillus spp. (8,19,21). Lactobacilli typically have n-C 16:0 , n-C 18:1 , and cyc-C 19 as the major carboxylate constituents, with lesser amounts of n-C 14:0 , n-C 16:1 , and n-C 18:0 and traces of odd-carbon-number acids in some species (6). Such fatty acid profiles are atypical of gram-positive groups but common in gram-positive bacteria (17). Other studies have analyzed polar lipids of lactobacilli and discovered that the vast majority of polar lipid is comprised of phosphatidylglycerol (PG) (8, 11), with smaller amounts of phosphatidic acid, diphosphatidylglycerol (cardiolipin), lysylphosphatidylglycerol (8, 10), phosphoglycolipids (10), and diglycosyldiacylglycerol (DGDG) (18).Virtually nothing is known of the distribution of individual molecular species within each type of phospholipid. In other groups of organisms, such an analysis has required expenditure of considerable time and effort to purify individual molecular species by chromatographic separation and then to analyze each molecular species in turn (2). An alternative approach, recently applied to the study of bacterial phospholipids (1, 3), is fast atom bombardment (FAB) mass spectrometry (MS) in which analysis of mixtures of molecular species is facilitated by the generation of ions retaining the intact molecular structure. FAB MS data for a single strain of Lactobacillus rhamnosus with respect to phospholipid molecular species have been published (7).The aim of this study was to determine the distribution of individual molecular species of phospholipids in a collection of Lactobacillus isolates.Fifteen Lactobacillus strains available from culture collections were analyzed (Table 1). All strains have been described previously (12, 13), and their identities were determined by using the API 50CHL test kit (API System, Vercieu, France) and the IDENTIFY computer program (5). Recent changes in the species assignments of some strains, not covered by the API 50CHL test kit for the identification of L. rhamnosus and L. paracasei subsp. paracasei (4), were incorporated into the computer program. For growth and harvesting, all strains were grown in 200-ml aliquots of MRS broth (Oxoid) for 18 to 24 h at 37ЊC as static batch cultures. Cultures were harvested by centrifugation and washed once in phosphate-buffered saline (pH 7.3). They were then washed in deionized water and freeze-dried. Phospholipid analysis was as follows. The methanol-chloroform extraction procedure, which used mechanical shaking at room temperature, was as described in a previous study (1). Phospholipid molecular species were sep...

The membrane phospholipids of Neisseria meningitidis and Neisseria gonorrhoeae as characterized by fast atom bombardment mass spectrometry

“…In addition, the FAB-MS spectra (see Figs 1 and 2) all show lower intensity ions at m\z 391,409, 434, 452 and 465. These ions could arise by molecular fragmentation of PE or PG molecules as described by Drucker et al (1995), or may be due, in part, to the presence of lysophospholipid molecules.…”

“…In addition, the following less-intense ions were also observed : 199, C12 : 0 ; 225, C14 : 1 ; 269, C17 : 0 ; 281, C18 : 1 ; 283, C18 : 0. These phospholipidderived carboxylate fragment ions were as reported by Drucker et al (1995). The total fatty acid composition of phospholipids from wild-type N. meningitidis and N. gonorrhoeae and meningococcal mutant strains were also analysed by methanolysis followed by trimethylsilylation and analysis by GLC-MS.…”

Modulation of the Lactobacillus acidophilus La-5 lipidome by different growth conditions

“…The lipid classes included the lipids identified in another study of L. acidophilus (Fernández Murga et al, 2001), and additionally identified MLCL, PA and QGDG, but not diglycodiacylglycerol (DGDG). DGDG could be an intermediate for TGDG and QGDG, as the glycosyltransferase responsible for transferring glyco-residues is able to transfer up to four residues to the precursor, diacylglycerol (Hölzl & Dörmann, 2007 have not been identified in other lipid studies on Lactobacillus species (Calvano et al, 2011;Drucker et al, 1995;Exterkate et al, 1971;Fernández Murga et al, 2001;Machado et al, 2004;Murga et al, 2000;Tymczyszyn et al, 2005). One reason for this difference could be that the composition of the lipid classes is dependent on the bacterial species and strain and only one research group has investigated the lipid classes of the L. acidophilus species within the last 15 years (Fernández Murga et al, 2001;Murga et al, 2000), and this was not the same strain as L. acidophilus La-5.…”

“…The methods used for L. acidophilus were thin layer chromatography and low-resolution fast atom bombardment mass spectrometry (Fernández Murga et al, 2001). The present study is one of only a few studies using mass spectrometry to identify the lipid species, and previously none of them have used state-of-the-art high-resolution FTMS-based lipidomics (Calvano et al, 2011;Drucker et al, 1995;Fernández Murga et al, 2001). Further studies using high-resolution MS techniques will show if the present findings can be generalized beyond L. acidophilus La-5.…”

“…We have found only one study on Lactobacillus species that gives the overall distribution for major lipid species. The lipids were identified by fast atom bombardment mass spectrometry (Drucker et al, 1995).…”