Phospholipid analogues of Porphyromonas gingivalis

Falsiporphyromonas endometrii gen. nov., sp. nov., isolated from the post-partum bovine uterus, and emended description of the genus Porphyromonas Shah and Collins 1988

Two black-pigmented, anaerobic bacterial strains, designated LMM 40T and LMM 41, were isolated from the bovine post-partum endometrium of two Holstein cows. The 16S rRNA gene sequences of the two strains were identical and showed the highest similarity to the 16S rRNA gene sequence of the type strain of Porphyromonas crevioricanis (90.2 %) but only 85.1 % 16S rRNA gene sequence similarity to the type strain of the type species of the genus Porphyromonas , Porphyromonas asaccharolytica . The major fatty acid profiles of the two strains were similar to those of species of the genus Porphyromonas , containing iso-C15 : 0 as the major component and moderate amounts of anteiso-C15 : 0, iso-C13 : 0, C15 : 0 and C16 : 0. Hydroxylated fatty acids, such as iso-C14 : 0 3-OH, iso-C16 : 0 3-OH and iso-C17 : 0 3-OH, were also detected. The quinone profiles were dominated by the menaquinones MK-8 and MK-9, while spermidine was the major polyamine. The polar lipid profiles contained major amounts of phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and two unidentified lipids and minor amounts of phosphatidylglycerol, an unidentified aminolipid, a second unidentified aminophospholipid and an unidentified glycolipid. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The genomic DNA G+C contents of LMM 40T and LMM 41 were 40.7 and 41.3 mol%, respectively. Based on a polyphasic approach, including phylogenetic analysis, physiological and biochemical tests as well as metabolic fingerprinting, it is proposed that the two strains are members of a novel genus and species, for which the name Falsiporphyromonas endometrii gen. nov., sp. nov. is proposed. The type strain of Falsiporphyromonas endometrii is LMM 40T ( = DSM 27210T = CCUG 64267T). An emended description of the genus Porphyromonas is also presented.

Application of TOF-SIMS with chemometrics to discriminate between four different yeast strains from the species Candida glabrata and Saccharomyces cerevisiae

We present a TOF-SIMS analysis of the cell surface differences between four yeast strains from two species, Candida glabrata and Saccharomyces cerevisiae (haploid strains BY4742 and BY4741 and the derived diploid BY4743). The study assesses the suitability of TOF-SIMS analysis in combination with statistical methods (principal component analysis, Fisher's discriminant analysis, and cluster analysis) for the discrimination between the four yeast strains. We demonstrate that a combination of these statistical methods identifies 34 ions, from a total data set of 1200, which can be used to distinguish between the four yeasts. The study discusses the assignments of surface cell membrane phospholipids for the identified ions and the resulting differences in the phospholipid pattern between the four yeasts, particularly in relation to ploidy and budding pattern. The method shows that fatty acids, phosphatidylglycerols, phosphatidylethanolamines, phosphatidylserines, and phosphatidylcholines, as well as cardiolipins, are of diagnostic importance.

Structures and biological activities of novel phosphatidylethanolamine lipids of Porphyromonas gingivalis

The Gram-negative periodontal pathogen Porphyromonas gingivalis synthesizes several classes of novel phosphorylated complex lipids, including the recently characterized phosphorylated dihydroceramides. These sphingolipids promote the interleukin-1 (IL-1)-mediated secretion of inflammatory mediators from fibroblasts, including prostaglandin E2 and 6-keto prostaglandin F2alpha, and alter gingival fibroblast morphology in culture. This report demonstrates that one additional class of phosphorylated complex lipids of P. gingivalis promotes IL-1-mediated secretory responses and morphological changes in cultured fibroblasts. Structural characterization identified the new phospholipid class as 1,2-diacyl phosphatidylethanolamine, which substituted predominantly with isobranched C15:0 and C13:0 fatty acids. The isobranched fatty acids, rather than unbranched fatty acids, and the phosphoethanolamine head group were identified as the essential structural elements required for the promotion of IL-1-mediated secretory responses. These structural components are also observed in specific phosphorylated sphingolipids of P. gingivalis and likely contribute to the biological activity of these substances, in addition to the phosphatidylethanolamine lipids described in this report.

Phospholipid molecular species distributions of Candida isolates from the UK and Iran

AIMS

Some species of Candida have been shown to differ with respect to their polar lipid fingerprints when analysed by fast atom bombardment mass spectrometry (FABMS). The aims of this study were to contribute to the existing body of information by (i) examining representatives of species not previously examined and (ii) seeking strains differences associated with country of origin (UK or Iran).

METHODS AND RESULTS

FABMS analysis was performed on extracted lipids of 22 strains representing eight species of Candida. The most abundant anion (19 isolates) in spectra was with mass to charge (m/z) 281, corresponding to C18:1 carboxylate. The major phospholipid analogue anions were m/z 515 and 501 (13 strains). These anions were putatively identified as the phosphatidyl molecular species PA(23 : 2) and PA(22 : 2) respectively. Data for strain pairs were compared using the Pearson's coefficient of linear correlation. The values generated were used to cluster strains by nearest-neighbour linkage, using both carboxylate and phospholipid analogue anion data. Isolates of C. parapsilosis were clearly distinct from other isolates. Iranian isolates tended to cluster together when phospholipid anion data were used. However, if carboxylate anion data were used, four Iranian isolates of C. albicans were tightly clustered with three UK isolates, of which two were C. albicans and one was C. dubliniensis.

CONCLUSION

It is concluded that both lower, and higher, mass peaks in FABMS spectra can be of potential value in comparing Candida isolates from different countries and from different species.

SIGNIFICANCE AND IMPACT OF THE STUDY

When polar lipids of different Candida species are compared, it is important to bear in mind that geographical differences affect results as has been observed with bacteria in similar studies.

Characterization of polar lipids of oral isolates of Candida, Pichia and Saccharomyces by Fast Atom Bombardment Mass Spectrometry (FAB MS)

AIMS

To characterize fatty acid and phospholipid analogue profiles of oral yeasts.

METHODS AND RESULTS

Twenty-seven strains of oral yeasts were cultured on SDA and lipids of freeze-dried cells were extracted and analysed by FAB MS. The most abundant carboxylate anion was m/z 281 (C18 : 1). The most intense phospholipid analogue ions were of PE, PG, PA and PI. Pichia etchellsii contained molecular species of PG and PE, whereas Saccharomyces cerevisiae had PA, PG and PE analogues. Mass spectra revealed that S. cerevisiae and Candida glabrata were distinct from one another and from the other species tested.

CONCLUSION

Oral yeasts largely differ with respect to their polar lipids. It is concluded that oral yeast species have distinctive fatty acid and phospholipid analogue anion profiles.

SIGNIFICANCE AND IMPACT OF THE STUDY

FAB MS provided novel chemotaxonomic information.

Phospholipid analogue profiles of Peptostreptococcus, Micromonas, and Finegoldia species analysed by fast atom bombardment mass spectrometry

Species of Peptostreptococcus cause a variety of infections, primarily abscesses of soft tissues, joints, and mucous membranes. The aim of this study was to compare the phospholipid analogue profiles of Peptostreptococcus species, represented by P. anaerobius, P. asaccharolyticus, P. indolicus, P. lacrimalis, and P. prevotii; Micromonas micros (P. micros) and Finegoldia magna (P. magnus). After anaerobic growth on blood-FAA, lipids extracted by chloroform-methanol (2:1 v/v) were purified, then analysed by fast atom bombardment mass spectrometry (FAB-MS) in negative ion mode. The major peaks with mass to charge (m/z) 719, 721, and 749, corresponded to phosphatidylglycerol analogues, namely PG (32:1), PG (32:0), and PG (34:0), which have been found previously in Lactobacillus spp., Clostridium difficile, and Staphylococcus spp. Other major peaks observed, with m/z 619, 647, 665, 675, 677, 687, 691, 693, 701, 703, 707, 733, and 746 have also been reported in one or more of these three species. However, other major peaks found here in Peptostreptococcus, Micromonas, and Finegoldia have not been described elsewhere; these are 501, 514, 515, 618, 659, 673, 676, 688, 690, 692, 694, 700, 706, 715, 718, 722, and 750. We conclude that Peptostreptococcus, Micromonas, and Finegoldia isolates are chemically unique.Key words: Peptostreptococcus, Micromonas, Finegoldia, phospholipids, FAB-MS.