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1.
Chem Phys Lipids ; 255: 105326, 2023 09.
Article in English | MEDLINE | ID: mdl-37414116

ABSTRACT

The growing consumption of fermented products has led to an increasing demand for lactic acid bacteria (LAB), especially for LAB tolerant to freezing/thawing conditions. Carnobacterium maltaromaticum is a psychrotrophic and freeze-thawing resistant lactic acid bacterium. The membrane is the primary site of damage during the cryo-preservation process and requires modulation to improve cryoresistance. However, knowledge about the membrane structure of this LAB genus is limited. We presented here the first study of the membrane lipid composition of C. maltaromaticum CNCM I-3298 including the polar heads and the fatty acid compositions of each lipid family (neutral lipids, glycolipids, phospholipids). The strain CNCM I-3298 is principally composed of glycolipids (32%) and phospholipids (55%). About 95% of glycolipids are dihexaosyldiglycerides while less than 5% are monohexaosyldiglycerides. The disaccharide chain of dihexaosyldiglycerides is composed of α-Gal(1-2)-α-Glc chain, evidenced for the first time in a LAB strain other than Lactobacillus strains. Phosphatidylglycerol is the main phospholipid (94%). All polar lipids are exceptionally rich in C18:1 (from 70% to 80%). Regarding the fatty acid composition, C. maltaromaticum CNCM I-3298 is an atypical bacterium within the genus Carnobacterium due to its high C18:1 proportion but resemble the other Carnobacterium strains as they mostly do not contain cyclic fatty acids.


Subject(s)
Carnobacterium , Membrane Lipids , Fatty Acids , Phospholipids
2.
Chem Commun (Camb) ; 52(11): 2318-21, 2016 Feb 07.
Article in English | MEDLINE | ID: mdl-26727964

ABSTRACT

Recent methodological developments in metabolic oligosaccharide engineering (MOE) pave the way for tremendous advances in glycobiology. Herein, we propose a Sequential Bioorthogonal Dual Strategy (SBDS) combining the use of two unprotected alkyne-tagged monosaccharide reporters (ManNAl and SiaNAl) with the bioligation of fluorescent probes by copper-catalysed azide-alkyne cycloaddition (CuAAC). With SBDS, we are able to shed light on trafficking and cellular uptake mechanisms of sialic acid. Using their corresponding analogues, we visualized that SiaNAl enters via endocytosis, whereas its biosynthetic intermediate ManNAl uptake is mediated by a yet unknown but specific plasma membrane transporter. Sialin, a lysosomal protein, is shown to be crucial for the export of exogenous sialic acid from lysosomes to the cytosol. Metabolic labeling with alkyne-tagged derivatives of N-acetylneuraminic acid (Neu5Ac) or N-acetylmannosamine (ManNAc) could thus be used to follow endocytosis in physiological vs. pathological conditions.


Subject(s)
Oligosaccharides/chemistry , Sialic Acids/chemistry , Catalysis , Copper/chemistry
3.
Biochemistry (Mosc) ; 80(7): 808-19, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26541996

ABSTRACT

Gangliosides are essential compounds of the plasma membrane involved in cell adhesion, proliferation, and recognition processes, as well as in the modulation of signal transduction pathways. These functions are mainly supported by the glycan moiety, and changes in the structure of gangliosides occur under pathological conditions including cancers. With progress in mass spectrometric analysis of gangliosides, the role of gangliosides in breast cancer progression was recently demonstrated. In this review, we summarize current knowledge on the biosynthesis of gangliosides and of the role of disialogangliosides in triple-negative breast cancer progression and metastasis. New perspectives in breast cancer therapy targeting gangliosides are also discussed.


Subject(s)
Breast Neoplasms/metabolism , Gangliosides/metabolism , Animals , Breast Neoplasms/genetics , Cell Membrane/metabolism , Female , Gangliosides/biosynthesis , Gangliosides/genetics , Humans , Signal Transduction
4.
Clin Microbiol Infect ; 21(1): 88.e1-6, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25636941

ABSTRACT

The diagnosis of systemic Candida infections is a recognized challenge. We developed a mass spectrometry strategy to detect signals from Candida molecules in patients' sera. Pre-analytical procedures were designed to extract oligosaccharides from serum. A peak m/z of at 365 was specifically revealed in sera from patients with candidaemia with regard to healthy controls. This biomarker was identified as a disaccharide, its presence did not correlate with mannanaemia or glucanaemia. Mouse models of Candida albicans colonization and infection showed that the signal was specifically associated with tissue invasion, suggesting that clinical evaluation of its usefulness in discriminating colonized and infected patients would be worthwhile.


Subject(s)
Biomarkers/blood , Candidiasis, Invasive/blood , Candidiasis, Invasive/diagnosis , Disaccharides/blood , Mycology/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Adult , Aged , Animals , Candida albicans , Candidiasis, Invasive/epidemiology , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , Middle Aged
5.
J Appl Microbiol ; 114(4): 1120-31, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23317349

ABSTRACT

AIMS: The purpose of this study was to quantify the extracellular matrix of Listeria monocytogenes biofilm. A preliminary study was carried out to establish a relationship between phylogenetic lineage of 27 strains and their ability to form biofilm in various conditions. METHODS AND RESULTS: Biofilm formation on microtitre plates of 27 strains of L. monocytogenes belonging to lineages I or II was evaluated in different conditions [two temperatures (37 and 22°C) and two media (tryptone soy broth yeast extract medium (TSBYE) and MCDB 202 defined medium)] using crystal violet assay. Lineage II strains produced significantly more biofilm than lineage I strains. In microtitre plates assay, biofilm quantities were greater in MCDB 202 vs TSBYE medium [confirmed by scanning electron microscopy (SEM) analysis] and at 37 vs 22°C. Cultivable bacteria from biofilm population on Petri dishes were enumerated in greater quantities in TSBYE than in MCDB 202 medium. The SEM investigation established that L. monocytogenes biofilms produce extracellular matrix in both media at 37°C. The amount of exopolymers in the extracellular matrix and the pH values were significantly higher in TSBYE than in MCDB 202 medium. The exception was the ScottA strain that presented similar pH values and exopolymer contents in both media. Proteins were the most abundant exopolymer components, followed by DNA and polysaccharides. CONCLUSIONS: The interpretation of results of biofilm quantification was depending on the growth conditions, the viability of the bacteria and the analysis method. The quantities of proteins, DNA and polysaccharides were different according to the strains and the medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This study screened the potential of a wide panel of L. monocytogenes strains to synthesize exopolymers in biofilm growing condition. The characterization of L. monocytogenes biofilm composition may help to develop new strategies to prevent the formation of biofilms and to remove the biofilms.


Subject(s)
Biofilms/growth & development , Extracellular Matrix/chemistry , Listeria monocytogenes/classification , Phylogeny , Bacterial Proteins/chemistry , Culture Media , DNA, Bacterial/chemistry , Listeria monocytogenes/genetics , Listeria monocytogenes/growth & development , Microscopy, Electron, Scanning , Polysaccharides, Bacterial/chemistry , Temperature
6.
Neurosci Lett ; 403(1-2): 147-50, 2006 Jul 31.
Article in English | MEDLINE | ID: mdl-16707221

ABSTRACT

We have measured by HPLC the neurotransmitter content in L(4) and L(5) spinal segmental levels in CONT rats, after 7 (HU7) and after 14 days (HU14) of hindlimb unloading. These segments are known to contain the hindlimb muscle motoneurons. The main result is the increase of two neuroexcitators (glutamate and aspartate) and two neuroinhibitors (glycine and GABA) at the L(5) spinal segmental level in HU7 group. Our data indicated that the neurotransmitter changes are restricted to spinal segmental level containing motoneurons from muscles which are strongly modified by HU condition.


Subject(s)
Amino Acids/metabolism , Neurotransmitter Agents/metabolism , Spinal Cord/metabolism , Weight-Bearing , Animals , Chromatography, High Pressure Liquid , Hindlimb , Male , Motor Neurons/metabolism , Muscle, Skeletal/innervation , Rats , Rats, Wistar
7.
Infect Immun ; 72(4): 2067-74, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15039328

ABSTRACT

The mycobacterial cell wall component lipoarabinomannan (LAM) has been described as a virulence factor of Mycobacterium tuberculosis, and modification of the terminal arabinan residues of this compound with mannose caps (producing mannosyl-capped LAM [ManLAM]) in M. tuberculosis or with phosphoinositol caps (producing phosphoinositol-capped LAM [PILAM]) in Mycobacterium smegmatis has been implicated in various functions associated with these lipoglycans. A structure-function analysis was performed by using LAMs and their biosynthetic precursor lipomannans (LMs) isolated from different mycobacterial species on the basis of their capacity to induce the production of interleukin-12 (IL-12) and/or apoptosis of macrophage cell lines. Independent of the mycobacterial species, ManLAMs did not induce IL-12 gene expression or apoptosis of macrophages, whereas PILAMs induced IL-12 secretion and apoptosis. Interestingly, uncapped LAM purified from Mycobacterium chelonae did not induce IL-12 secretion or apoptosis. Furthermore, LMs, independent of their mycobacterial origins, were potent inducers of IL-12 and apoptosis. The precursor of LM, phosphatidyl-myo-inositol dimannoside, had no activity, suggesting that the mannan core of LM was required for the activity of LM. The specific interaction of LM with Toll-like receptor 2 (TLR-2) but not with TLR-4 suggested that these responses were mediated via the TLR-2 signaling pathway. Our experiments revealed an important immunostimulatory activity of the biosynthetic LAM precursor LM. The ratio of LAM to LM in the cell wall of mycobacteria may be an important determinant of virulence, and enzymes that modify LM could provide targets for development of antituberculosis drugs and for derivation of attenuated strains of M. tuberculosis.


Subject(s)
Apoptosis/drug effects , Interleukin-12/metabolism , Lipopolysaccharides/pharmacology , Macrophage Activation/drug effects , Mycobacterium tuberculosis/chemistry , Mycobacterium tuberculosis/immunology , Animals , Apoptosis/physiology , Bone Marrow Cells , CHO Cells , Cell Line , Cricetinae , Humans , Lipopolysaccharides/chemistry , Macrophages/immunology , Mice , Mice, Inbred BALB C
8.
Biochem J ; 360(Pt 1): 179-88, 2001 Nov 15.
Article in English | MEDLINE | ID: mdl-11696006

ABSTRACT

Cytosolic and nuclear O-linked N-acetylglucosaminylation has been proposed to be involved in the nuclear transport of cytosolic proteins. We have isolated nuclear and cytosolic N-acetyl-d-glucosamine (GlcNAc)-specific lectins from adult rat liver by affinity chromatography on immobilized GlcNAc and identified these lectins, by a proteomic approach, as belonging to the heat-shock protein (HSP)-70 family (one of them being heat-shock cognate 70 stress protein). Two-dimensional electrophoresis indicated that the HSP-70 fraction contained three equally abundant proteins with molecular masses of 70, 65 and 55 kDa. The p70 and p65 proteins are phosphorylated and are themselves O-linked GlcNAc (O-GlcNAc)-modified. The HSP-70 associated into high molecular mass complexes that dissociated in the presence of reductive and chaotropic agents. The lectin(s) present in this complex was (were) able to recognize cytosolic and nuclear ligands, which have been isolated using wheat germ agglutinin affinity chromatography. These ligands are O-GlcNAc glycosylated as demonstrated by [(3)H]galactose incorporation and analysis of the products released by reductive beta-elimination. The isolated lectins specifically recognized ligands present in both the cytosol and the nucleus of human resting lymphocytes. These results demonstrated the existence of endogenous GlcNAc-specific lectins, identified as HSP-70 proteins, which could act as a shuttle for the nucleo-cytoplasmic transport of O-GlcNAc glycoproteins between the cytosol and the nucleus.


Subject(s)
Acetylglucosamine/metabolism , Cell Nucleus/metabolism , Cytosol/metabolism , Heat-Shock Proteins/metabolism , Lectins/chemistry , Liver/metabolism , Animals , Biotinylation , Blotting, Western , Electrophoresis, Gel, Two-Dimensional , Electrophoresis, Polyacrylamide Gel , Glycoproteins/metabolism , Isoelectric Focusing , Ligands , Lymphocytes/metabolism , Phosphorylation , Rats , Rats, Wistar , Sepharose/chemistry
9.
Biochem J ; 357(Pt 1): 167-82, 2001 Jul 01.
Article in English | MEDLINE | ID: mdl-11415447

ABSTRACT

The free-living nematode Caenorhabditis elegans is a relevant model for studies on the role of glycoconjugates during development of multicellular organisms. Several genes coding for glycosyltransferases involved in the synthesis of N- and O-linked glycans have already been isolated, but, apart from repetitive dimers of glycosaminoglycans, no detailed structure of either type of component has been published so far. This study aimed to establish the structures of the major O-glycans synthesized by C. elegans to give an insight into the endogenous glycosyltransferase activities expressed in this organism. By the use of NMR and MS, we have resolved the sequence of seven of these components that present very unusual features. Most of them were characterized by the type-1 core substituted on Gal and/or GalNAc by (beta1-4)Glc and (beta1-6)Glc residues. Another compound exhibited the GalNAc(beta1-4)N-acetylglucosaminitol sequence in the terminal position, to which was attached a tetramer of beta-Gal substituted by both Fuc and 2-O-methyl-fucose residues. Our experimental procedure led also to the isolation of glycosaminoglycan-like components and oligomannosyl-type N-glycans. In particular, the data confirmed that C. elegans synthesizes the ubiquitous linker sequence GlcA(beta1-3)Gal(beta1-3)Gal(beta1-4)Xyl.


Subject(s)
Caenorhabditis elegans/metabolism , Glucose/metabolism , Oligosaccharides/chemistry , Polysaccharides/chemistry , Polysaccharides/chemical synthesis , Animals , Carbohydrate Conformation , Carbohydrate Sequence , Chondroitin/chemistry , Chromatography, High Pressure Liquid , Glucose/analysis , Methylation , Molecular Sequence Data , Monosaccharides/analysis , Mucins/chemistry , Nuclear Magnetic Resonance, Biomolecular , Polysaccharides/isolation & purification
10.
Biochem J ; 352 Pt 2: 449-63, 2000 Dec 01.
Article in English | MEDLINE | ID: mdl-11085939

ABSTRACT

Eggs from Xenopus laevis are surrounded by several layers of jelly that are needed for proper fertilization. Jelly coat is composed of high-molecular-mass glycoconjugates to which are bound many globular proteins. O-glycans released from the jelly coat of X. laevis have been partially described in previous studies. In this study, we compared the glycosylation pattern of the egg jelly coat isolated from six specimens of X. laevis. The O-glycans were released from jelly coats by alkali/borohydride treatment. Structural characterization was performed through a combination of one- and two-dimensional (1)H-NMR and methylation analysis. This allowed the description of a new family of sulphated O-glycans present in jelly coats of all X. laevis. However, the jelly O-glycans showed a low extent of polymorphism between specimens. This intra-specific variability was restricted to the terminal substitution of O-linked oligosaccharides. The differential expression of two glycosyltransferase [an alpha-(1-->4) galactosyltransferase and an alpha-(1-->3) fucosyltransferase] activities resulted in the characterization of four phenotypes of X. laevis. Furthermore, electrophoretic analysis suggested that the high-molecular-mass fraction of jelly coat was mostly composed of mucin-type glycoproteins. Blot analysis with lectins confirmed that the glycan variability was borne by these mucin-type components. However, fertilization assays suggested that the glycan polymorphism had no repercussion on egg fertilizability.


Subject(s)
Mucins/chemistry , Ovum/chemistry , Polysaccharides/chemistry , Animals , Blotting, Western , Carbohydrate Conformation , Carbohydrate Sequence , Electrophoresis, Polyacrylamide Gel , Fertilization , Glycosylation , Molecular Sequence Data , Nuclear Magnetic Resonance, Biomolecular , Phenotype , Polysaccharides/metabolism , Xenopus laevis
11.
Carbohydr Res ; 320(3-4): 230-8, 1999 Aug 15.
Article in English | MEDLINE | ID: mdl-10573860

ABSTRACT

The structures of two sulfated octasaccharides and one sulfated nonasaccharide isolated from human milk have been investigated. Using 13C and 1H NMR spectroscopy and ESMS, the following structures 1-3 were established: [formula: see text].


Subject(s)
Milk, Human/chemistry , Oligosaccharides/chemistry , Sulfuric Acid Esters/chemistry , Animals , Carbohydrate Conformation , Carbohydrate Sequence , Female , Fucose/chemistry , Humans , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Sequence Data , Oligosaccharides/isolation & purification , Sulfuric Acid Esters/isolation & purification
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