Enzymatic synthesis of unique sialyloligosaccharides using marine bacterial α-(2→3)- and α-(2→6)-sialyltransferases

We investigated the acceptor substrate specificities of marine bacterial α-(2→3)-sialyltransferase cloned from Photobacterium sp. JT-ISH-224 and α-(2→6)-sialyltransferase cloned from Photobacterium damselae JT0160 using several saccharides as acceptor substrates. After purifying the enzymatic reaction products, we confirmed their structure by NMR spectroscopy. The α-(2→3)-sialyltransferase transferred N-acetylneuraminic acid (Neu5Ac) from cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac) to the β-anomeric hydroxyl groups of mannose (Man) and α-Manp-(1→6)-Manp, and α-(2→6)-sialyltransferase transferred N-acetylneuraminic acid to the 6-OH groups of the non-reducing end galactose residues in β-Galp-(1→3)-GlcpNAc and β-Galp-(1→6)-GlcpNAc.     

O-Methylated mannogalactan from the microalga Coccomyxa mucigena, symbiotic partner of the lichenized fungus Peltigera aphthosa

A structural study of the carbohydrates from Coccomyxa mucigena, the symbiotic algal partner of the lichenized fungus Peltigera aphthosa, was carried out. It produced an O-methylated mannogalactan, with a (1 → 6)-linked β-galactopyranose main-chain partially substituted at O-3 by β-Galp, 3-OMe-α-Manp or α-Manp units. There were no similarities with polysaccharides previously found in the lichen thallus of P. aphthosa. Moreover, the influence of lichenization in polysaccharide production by symbiotic microalgae and the nature of the photobiont in carbohydrate production in lichen symbiosis are also discussed.     

Purification and some properties of the isomaltodextranase of Actinomadura strain r10 and comparison with that of Arthrobacter globiformis t6

A newly isolated soil-actinomycete, Actinomadura strain R10 (NRRL B-11411), produces an extracellular isomaltodextranase (optinal pH, 5.0) that was purified to homogeneity. It exolytically releases isomaltose and a minor trisaccharide product,α-d-Glcp-(1→3)-α-d-Glcp, from dextran B-512 and, in addition, forms transient transisomaltosylation products. This pattern of products is qualitatively similar to that previously reported for the isomaltodextranase (EC 3.2.1.94, optimal pH, 4-0) of Arthrobacter globiformis T6 (NRRL B-4425). The Arthrobacter isomaltodextranase is most active on the (1→6)-α-d-glucopyranosidic linkage, but the relative activity increases with the degrees of polymerization of isomalto-oligosaccharide substrates. In contrast, the relative activity of Actinomadura isomaltodextranase is almost constant throughout the same series of substrates, and is much higher on 3 O- and 4-O-α-isomaltosyl-oligosaccharides than that exhibited by the Arthrobacter enzyme; the activity of Actinomadura isomaltodextranase on the α-(1→4) linkage is 3-4 times greater than on the α-(1→6). These results indicate that, generically, the bacterial isomaltodextranase is a glycanase, whereas the actinomycetal enzyme is a glycosidase. This difference is reflected in the hydrolysis of dextrans, especially of dextran B-1355 (fraction S), which has a high content of unbranched α-(1→3) linked residues. In the digest of this dextran with Arthrobacter isomaltodextranse, short-chain fragments accumulated that were absent when the Actinomadura enzyme was employed.     

Structural characterization of a highly branched polysaccharide from the seeds of Plantago asiatica L.

In this paper, polysaccharides were extracted from the seeds of Plantago asiatica L. with hot water and separated into three fractions PLP-1 (18.9%), PLP-2 (52.6%) and PLP-3 (28.5%) by Sephacryl™ S-400 HR column chomatography. The main fraction PLP-2's structure was elucidated using oxalic acid hydrolysis, partial acid hydrolysis, methylation, GC, GC-MS, 1D and 2D NMR. PLP-2 was composed of Rha, Ara, Xyl, Man, Glc and Gal, in a molar ratio of 0.05:1.00:1.90:0.05:0.06:0.10. Its uronic acid was GlcA. PLP-2 was highly branched heteroxylan which consisted of a β-1,4-linked Xylp backbone with side chains attached to O-2 or O-3. The side chains consisted of β-T-linked Xylp, α-T-linked Araf, α-T-linked GlcAp, β-Xylp-(1 → 3)-α-Araf and α-Araf-(1 → 3)-β-Xylp, etc. Based on these results, the structure of PLP-2 was proposed.     

Isolation of phosphorylated polysaccharides from algae: the immunostimulatory principle of Chlorella pyrenoidosa

The major immunostimulatory principle in the hot aqueous extract of Chlorella pyrenoidosa has been isolated by a sequence of ethanol precipitation, precipitation with a cationic surfactant (CTAB), size exclusion chromatography, and anion exchange chromatography. A series of phosphorylated polysaccharides were obtained having different molecular masses but with similar structures. The higher molecular mass fractions showed considerable activity in the stimulation of mouse peritoneal macrophages to synthesize nitric oxide. The structure of the major polysaccharide was established by sugar analysis, configurational analysis, and 1D and 2D NMR experiments at 500 and 800 MHz on the parent polysaccharide, the de-O-acetylated polysaccharide, and on the components obtained after hydrolysis of the phosphate diesters. It had a β-d-Galp-(1→3)-β-d-Galp-(1→3)-backbone with half of the Galp units substituted at O-6 by terminal β-d-Glcp units. The remaining Galp units were substituted on O-6 by about equal amounts of α-d-Manp-1-phosphate and 3-O-Me-α-Manp-1-phosphate diesters. The substituents were not located in a regularly alternating fashion on the backbone. The O-acetyl groups were largely located on O-2 and O-4 of Galp and 35% of the Galp residues were O-acetylated. This is the second observation of a phosphorylated polysaccharide in an alga and the first where it is present to a significant extent.     

Isolation and characterization of poly- and oligosaccharides from the red microalga Porphyridium sp.

The current study forms part of an ongoing research effort focusing on the elucidation of the chemical structure of the sulfated extracellular polysaccharide of the red microalga Porphyridium sp. (UTEX 637). We report here on the chemical structure of a fraction separated from an acidic crude extract of the polysaccharide, as investigated by methylation analysis, carboxyl reduction-methylation analysis, desulfation-methylation analysis, partial acid hydrolysis, Smith degradation, together with 1D and 2D ¹H and ¹³C NMR spectroscopy. This fraction with a molar mass of 2.39 × 10⁵ g mol⁻¹ comprised d- and l-Gal, d-Glc, d-Xyl, d-GlcA, and sulfate groups in a molar ratio of 1.0:1.1:2.1:0.2:0.7. The almost linear backbone of the fraction is composed of (1→2)- or (1→4)-linked d-xylopyranosyl, (1→3)-linked l-galactopyranosyl, (1→3)-linked d-glucopyranosyl, and (1→3)-linked d-glucopyranosyluronic acid and comprises a possible acidic building unit:

[(2 or 4)-β-d-Xylp-(l→3)]_m-α-d-Glcp-(1→3)-α-d-GlcpA-(1→3)-l-Galp(l→

Attached to the backbone are sulfate groups and nonreducing terminal d-xylopyranosyl and galactopyranosyl residues, which occur at the O-6 positions of Glc-derived moieties in the main chain.     

Structure of the O-polysaccharide of the lipopolysaccharide of Pragia fontium 97U116

The O-polysaccharide of Pragia fontium 97U116 was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar analysis along with 1D and 2D ¹H and ¹³C NMR spectroscopy. The following structure of the pentasaccharide-repeating unit was established: →2)-α-d-Galf-(1→3)-α-l-Rhap2Ac^I-(1→4)-α-d-GlcpNAc^I-(1→2)-α-l-Rhap^II-(1→3)-β-d-GlcpNAc^II-(1→     

Structure of the O-polysaccharide of Salmonella enterica O41

An O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Salmonella enterica O41, and the following structure of the O-unit was determined by chemical analyses along with 1D and 2D ¹H and ¹³C NMR spectroscopy:→2)-β-d-Manp-(1→4)-α-d-Glcp-(1→3)-α-l-QuipNAc-(1→3)-α-d-GlcpNAc-(1→where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose. The structure established is in agreement with the O-antigen gene cluster of S. enterica O41 and tentative assignment of the gene functions reported earlier.     

An acetylated galactomannoglucan from the stems of Dendrobium nobile Lindl

A water-soluble polysaccharide DNP-W2 composed of glucose, mannose, and galactose in the molar ratio of 6.1:2.9:2.0 had been isolated from the stems of Dendrobium nobile. Its molecular weight was 1.8 × 10⁴ Da determined by HPGPC. Structural features of DNP-W2 were investigated by a combination of chemical and instrumental analysis, including FTIR, GC, GC-MS, periodate oxidation-Smith degradation, methylation analysis, partial acid hydrolysis, and NMR spectroscopy. The results showed that DNP-W2 is a 2-O-acetylgalactomannoglucan and has a backbone consisting of (1→4)-linked β-d-Glcp, (1→6)-linked β-d-Glcp, and (1→4)-linked β-d-Manp, with branches at O-6 of (1→4)-linked β-d-Glcp and β-d-Manp. The branches are composed of α-d-Galp. The acetyl groups are substituted at O-2 of (1→4)-linked Manp. Preliminary tests in vitro reveals that DNP-W2 can stimulate ConA- and LPS-induced T and B lymphocyte proliferation.     

The O-antigen of Salmonella enterica O13 and its relation to the O-antigen of Escherichia coli O127

The following structure of the O-polysaccharide (O-antigen) of Salmonella enterica O13 was established by chemical analyses along with 2D ¹H and ¹³C NMR spectroscopy:→2)-α-l-Fucp-(1→2)-β-d-Galp-(1→3)-α-d-GalpNAc-(1→3)-α-d-GlcpNAc-(1→The O-antigen of S. enterica O13 was found to be closely related to that of Escherichia coli O127, which differs only in the presence of a GalNAc residue in place of the GlcNAc residue and O-acetylation. The location of the O-acetyl groups in the E. coli O127 polysaccharide was determined. The structures of the O-polysaccharides studied are in agreement with the DNA sequence of the O-antigen gene clusters of S. enterica O13 and E. coli O127 reported earlier.     

Acylated flavonol tetraglycosides from Delphinium gracile

An ethanol extract of the aerial parts of Delphinium gracile DC. yielded five flavonol glycosides quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-caffeoyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (1), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (2), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(Z-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (3), kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (4) kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (5) in addition to 4-(β-d-glucopyranosyloxy)-6-methyl-2H-pyran-2-one (6) and rutin. Structures were elucidated by spectroscopic methods.     

A dual role for the lex2 locus: identification of galactosyltransferase activity in non-typeable Haemophilus influenzae strains 1124 and 2019

Lipopolysaccharide (LPS) of Haemophilus influenzae comprises a conserved tri-l-glycero-d-manno-heptosyl inner-core moiety (l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-[β-d-GlcIp-(1→4)]-l-α-d-Hepp-(1→5)-α-Kdop) to which addition of β-d-Glcp to O-4 of GlcI in serotype b strains is controlled by the gene lex2B. In non-typeable H. influenzae strains 1124 and 2019, however, a β-d-Galp is linked to O-4 of GlcI. In order to test the hypothesis that the lex2 locus is involved in the expression of β-d-Galp-(1→4-β-d-Glcp-(1→ from HepI, lex2B was inactivated in strains 1124 and 2019, and LPS glycoform populations from the resulting mutant strains were investigated. Detailed structural analyses using NMR techniques and electrospray-ionisation mass spectrometry (ESIMS) on O-deacylated LPS and core oligosaccharide material (OS), as well as ESIMSⁿ on permethylated dephosphorylated OS, indicated both lex2B mutant strains to express only β-d-Glcp extensions from HepI. This provides strong evidence that Lex2B functions as a galactosyltransferase adding a β-d-Galp to O-4 of GlcI in these strains, indicating that allelic polymorphisms in the lex2B sequence direct alternative functions of the gene product.     

A similarity in the O-acetylation pattern of the O-antigens of Shigellaflexneri types 1a, 1b, and 2a

Shigella flexneri type 2a is the first, and type 1b is the second, most prevalent isolates from patients with shigellosis in Russia. The O-specific polysaccharides (OPSs, O-antigens) of S. flexneri types 1-5 possess a common →2)-α-l-RhapIII-(1→2)-α-l-RhapII-(1→3)-α-l-RhapI-(1→3)-β-d-GlcpNAc-(1→ backbone and differ from each other in its glucosylation or/and O-acetylation at various positions, the modifications being responsible for various O-factors. It was suggested that O-factor 6 expressed by type 1b is associated with O-acetylation of RhaI at position 2 but more than one O-acetyl group has been detected in the type 1b OPS [Kenne, L. et al. Eur. J. Biochem.1978, 91, 279-284]. In this work, O-acetylation of RhapI in the type 1b OPS was confirmed by NMR spectroscopy and location of an additional O-acetyl group at position either 3 (major) or 4 (minor) of RhapIII was determined. Type 1a differs from type 1b in the lack of O-acetylation of RhapI only. In type 2a, in addition to two reported major O-acetyl groups at position 6 of GlcNAc and position 3 of RhapIII [Kubler-Kielb, J. et al. Carbohydr. Res.2007, 342, 643-647], a minor O-acetyl group was found at position 4 of RhaIII. Therefore, RhapIII is O-acetylated in the same manner in all three S. flexneri serotypes studied.     

Structural analysis of the O-specific polysaccharide isolated from Plesiomonas shigelloides O51 lipopolysaccharide

Plesiomonasshigelloides strain CNCTC 110/92 (O51) was identified as a new example of plesiomonads synthesising lipopolysaccharides (LPSs) that show preference for a non-aqueous surrounding during phenol/water extraction. Chemical analyses combined with ¹H and ¹³C NMR spectroscopy, MALDI-TOF and ESI mass spectrometry showed that the repeating units of the O-specific polysaccharides isolated from phenol and water phase LPSs of P. shigelloides O51 have the same structure: →4)-β-d-GlcpNAc3NRA-(1→4)-α-l-FucpAm3OAc-(1→3)-α-d-QuipNAc-(1→, containing the rare sugar constituent 2,3-diamino-2,3-dideoxyglucuronic acid (GlcpNAc3NRA), and substituents such as d-3-hydroxybutyric acid (R) and acetamidino group (Am). The HR-MAS NMR spectra obtained for the isolated LPSs and directly on bacteria indicated that the O-acetylation pattern was consistent throughout the entire preparation. The ¹H chemical shift values of the structure reporter groups identified in the isolated O-antigens matched those present in bacteria. We have found that the O-antigens recovered from the phenol phase showed a higher degree of polymerisation than those isolated from the water phase.     

Structural analysis of water-soluble polysaccharides in the fruiting body of Dictyophora indusiata and their in vivo antioxidant activities

The water-soluble Dictyophora indusiata polysaccharides (DIP) were extracted from the fruiting body of D. indusiata. The structural features of purified DIPs I and II were investigated. The results indicated that DIP I was composed of glucose (Glc) and mannose (Man) with molecular weight of 2100 kDa, while DIP II comprised of xylose (Xyl), galactose (Gal), glucose (Glc) and Man with molecular weight of 18.16 kDa. The glycosidic linkage of DIP I was composed of →1)-Glc-(6→: →1)-Man-(3,6→ with the ratio of 5.6:1.0, while DIP II was composed of →1)-Glc-(6→: →1)-Man-(3,6→: →1)-Xyl-(5→: →1)-Gal-(3→: →1)-Gal-(6→: with the ratio of 4.9: 15.5: 7.8: 1.0: 5.7. DIP significantly (P < 0.05) decreased the malondialdehyde (MDA), lipofuscin levels and increased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities of mice. The strong in vivo antioxidant activity indicated DIP had great potential as functional food.     

Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 94/D4 and the international type strain Escherichia coli O82

The structure of the O-antigen polysaccharides (PS) from the enteroaggregative Escherichia coli strain 94/D4 and the international type strain E. coli O82 have been determined. Component analysis and ¹H, ¹³C, and ³¹P NMR spectroscopy experiments were employed to elucidate the structure. Inter-residue correlations were determined by ¹H, ¹³C-heteronuclear multiple-bond correlation, and ¹H, ¹H-NOESY experiments. d-GroA as a substituent is linked via its O-2 in a phosphodiester-linkage to O-6 of the α-d-Glcp residue. The PS is composed of tetrasaccharide repeating units with the following structure:→4)-α-d-Glcp6-(P-2-d-GroA)-(1→4)-β-d-Galp-(1→4)-β-d-Glcp-(1→3)-β-d-GlcpNAc-(1→Cross-peaks of low intensity from an α-d-Glcp residue were present in the NMR spectra and spectral analysis indicates that they originate from the terminal residue of the polysaccharide. Consequently, the biological repeating unit has a 3-substituted N-acetyl-d-glucosamine residue at its reducing end. Enzyme immunoassay using specific anti-E. coli O82 rabbit sera showed identical reactivity to the LPS of the two strains, in agreement with the structural analysis of their O-antigen polysaccharides.     

Structure of a polysaccharide from the lipopolysaccharides of Vibrio vulnificus strains CECT 5198 and S3-I2-36, which is remarkably similar to the O-polysaccharide of Pseudoalteromonas rubra ATCC 29570

High-molecular-mass polysaccharides were released by mild acid degradation of the lipopolysaccharides of two wild-type Vibrio vulnificus strain, a flagellated motile strain CECT 5198 and a non-flagellated non-motile strain S3-I2-36. Studies by sugar analysis and partial acid hydrolysis along with ¹H and ¹³C NMR spectroscopies showed that the polysaccharides from both strains have the same trisaccharide repeating unit of the following structure:→4)-β-d-GlcpNAc3NAcylAN-(1→4)-α-l-GalpNAmA-(1→3)-α-d-QuipNAc-(1→where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose, GalNAmA for 2-acetimidoylamino-2-deoxygalacturonic acid, GlcNAc3NAcylAN for 2-acetamido-3-acylamino-2,3-dideoxyglucuronamide and acyl for 4-d-malyl (∼30%) or 2-O-acetyl-4-d-malyl (∼70%). The structure of the polysaccharide studied resembles much that of a marine bacterium Pseudoalteromonas rubra ATCC 29570 reinvestigated in this work. The latter differs in (i) the absolute configuration of malic acid (l vs d), (ii) 3-O-acetylation of GalNAmA and (iii) replacement of QuiNAc with its 4-keto biosynthetic precursor.     

Triterpenoid saponins from a cytotoxic root extract of Sideroxylonfoetidissimum subsp. gaumeri

Evaluation of the cytotoxicity of an ethanolic root extract of Sideroxylonfoetidissimum subsp. gaumeri (Sapotaceae) revealed activity against the murine macrophage-like cell line RAW 264.7. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which four saponins were isolated. Use of 1D (¹H, ¹³C, DEPT135) and 2D (COSY, TOCSY, HSQC, and HMBC) NMR, mass spectrometry and sugar analysis gave their structures as 3-O-(β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, 3-O-β-d-glucopyranosyl-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, 3-O-(β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, and the known compound, 3-O-β-d-glucopyranosyl-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-protobassic acid. Two further saponins were obtained from the same fraction, but as a 5:4 mixture comprising 3-O-(β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid and 3-O-(β-d-apiofuranosyl-(1 → 3)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, respectively. This showed greater cytotoxicity (IC₅₀ = 11.9 ± 1.5 μg/ml) towards RAW 264.7 cells than the original extract (IC₅₀ = 39.5 ± 4.1 μg/ml), and the saponin-containing fraction derived from it (IC₅₀ = 33.7 ± 6.2 μg/ml).     

Structural determination of the O-chain polysaccharide from the haloalkaliphilic Halomonas alkaliantarctica bacterium strain CRSS

In hypersaline environments there are plenty of microorganisms belonging to both Bacteria and Archaea domains. These extremophiles have developed biochemical adaptations which comprise the accumulation of molar concentrations of potassium and chloride and the biosynthesis and/or the accumulation of organic osmotic solutes (osmolytes) within the cytoplasm. Moreover, to maintain the turgor of the cells halophiles enhance the production of anionic phospholipids and alter the fatty acid composition of the membrane lipids, but very little is known about adaptational structural changes of the lipopolysaccharides (LPS), the main constituent of the outer leaflet of the outer membrane of Gram-negative bacteria. The aim of this work is to investigate the chemical structure of these LPS in order to provide insight into the adaptation mechanism of halophiles to live at high salt concentration. For this, Halomonas alkaliantarctica, a haloalkaliphilic Gram-negative bacterium isolated from salt sediments of a saline lake in Cape Russell in the Antarctic continent, was cultivated and the LPS were extracted and analysed. The structure of the O-chain of the LPS from H. alkaliantarctica was determined by chemical analysis, 1-D and 2-D NMR spectroscopy. The polysaccharide was constituted of a linear trisaccharidic repeating unit as follows:→3)-β-l-Rhap-(1→4)-α-l-Rhap-(1→3)-α-l-Rhap-(1→A comparison among the O-chain structures of H. alkaliantarctica and other Halomonas species is also reported.     

Novel bacterial polar lipids containing ether-linked alkyl chains,the structures and biological properties of the four major glycolipids from Propionibacterium propionicum PCM 2431 (ATCC 14157T)

Propionibacterium propionicum belongs to the "acnes group" of propionibacteria, which is currently considered as clinically important because of its growing potential in infections, in particular with those connected with immune system dysfunctions. Propionibacteria are thought to be actinomycete-like microorganisms and may still cause diagnostic difficulties. The chloroform-methanol extracts of the cell mass of P. propionicum (type strain) gave in TLC analysis the characteristic glycolipid profile containing four major glycolipids, labeled G(1) through G(4). These polar lipids were found to be useful chemotaxonomic markers to differentiate P. propionicum from other cutaneous propionibacteria, in particular from strains of the acnes group. Glycolipids G(1)-G(4) were isolated and purified using gel-permeation chromatography, TLC, and high performance liquid chromatography, and their structures were elucidated by compositional and methylation analyses, specific chemical degradations, MALDI-TOF mass spectrometry, and (1)H NMR and (13)C NMR spectroscopy, including HMBC, TOCSY, HMQC, and NOESY experiments. Glycolipids G(2) and G(3) possess as backbone alpha-d-Glcp-(1 --> 3)-alpha-d-Glcp-(1 --> 1)-Gro (Gro, glycerol), in which position O-2 of the glycerol residue is acylated by a fatty acid (mainly C(15):0) while O-3 is substituted by an alkyl ether chain. In glycolipid G(3), an additional fatty acyl chain was linked to O-6 of the terminal glucose residue. Glycolipid G(4) was structurally related to G(2) but devoid of one glucose residue. Glycolipid G(1) was isolated in small amounts, and its structure was therefore deduced from MALDI-TOF-MS experiments alone, which revealed that it possessed the structure of G(2) but was lacking one fatty acid residue. In studies on the biological properties of P. propionicum glycolipids, the anti-P. propionicum rabbit antisera reacted in dot enzyme-immunoblotting test with G(2) and G(3). Glycolipid G(3) was able to induce the delayed type of hypersensitivity. The results indicated that these novel ether linkage-containing polar glycolipids are immunogenic and possibly active in hypersensitivity, and thus, in pathogenesis.