17 research outputs found

    Natural Variability in Bovine Milk Oligosaccharides from Danish Jersey and Holstein-Friesian Breeds

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    Free oligosaccharides are key components of human milk and play multiple roles in the health of the neonate, by stimulating growth of selected beneficial bacteria in the gut, participating in development of the brain, and exerting antipathogenic activity. However, the concentration of oligosaccharides is low in mature bovine milk, normally used for infant formula, compared with both human colostrum and mature human milk. Characterization of bovine milk oligosaccharides in different breeds is crucial for the identification of viable sources for oligosaccharide purification. An improved source of oligosaccharides can lead to infant formula with improved oligosaccharide functionality. In the present study we have analyzed milk oligosaccharides by high-performance liquid chromatography chip quadrupole time-of-flight mass spectrometry and performed a detailed data analysis using both univariate and multivariate methods. Both statistical tools revealed several differences in oligosaccharide profiles between milk samples from the two Danish breeds, Jersey and Holstein-Friesians. Jersey milk contained higher relative amounts of both sialylated and the more complex neutral fucosylated oligosaccharides, while the Holstein-Friesian milk had higher abundance of smaller and simpler neutral oligosaccharides. The statistical analyses revealed that Jersey milk contains levels of fucosylated oligosaccharides significantly higher than that of Holstein-Friesian milk. Jersey milk also possesses oligosaccharides with a higher degree of complexity and functional residues (fucose and sialic acid), suggesting it may therefore offer advantages in term of a wider array of bioactivities

    RP-HPLC separation profile of muropeptides obtained from <i>L. casei</i> BL23 PG.

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    <p>PG was digested by mutanolysin (A) or by mutanolysin and recombinant Lc-p75 (B). Numbers correspond to the main muropeptides which amounts changed between Panel A and B. Letters indicate new peaks present in Panel B and absent in Panel A. Complete annotation of the chromatograms is presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032301#pone.0032301.s004" target="_blank">Figure S3</a>.</p

    Main muropeptides from <i>L. casei</i> BL23 PG hydrolyzed by Lc-p75 and main products of digestion.

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    a<p>Peak numbers refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032301#pone-0032301-g002" target="_blank">Figure 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032301#pone.0032301.s004" target="_blank">Figure S3</a>. New peaks obtained after Lc-p75 digestion, are indicated by letters.</p>b<p>Di, disaccharide dipeptide (L-Ala-D-iGln); Tri, disaccharide tripeptide (L-Ala-D-iGln-L-Lys); Tetra, disaccharide tetrapeptide (L-Ala-D-iGln-L-Lys-D-Ala); Disaccharide, GlcNAc-MurNAc; Ac, acetylation on MurNAc, iGln, isoglutamine; N, D-Asn; A, D-Ala; K, L-Lys.</p>c<p>Sodiated molecular ions were the most abundant ones on MALDI-TOF mass spectra for all muropeptides.</p>d<p>Percentage of each peak was calculated as the ratio of the peak area over the sum of areas of all the peaks identified in the corresponding chromatogram (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032301#pone.0032301.s008" target="_blank">Table S3</a>).</p>e<p>ND, non detected.</p

    Detection of Lc-p75 in culture supernatant.

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    <p>Analysis by SDS-PAGE (A, B) and zymogram assay (C, D) of the culture supernatant of wild type BL23 (A, C) and negative mutant (B, D) grown on AOAC medium. Lc-p75 is indicated by an arrow.</p

    Indirect immunofluorescence localization of Strep-tagged Lc-p75 in <i>L. casei</i>.

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    <p>Strep-tagged Lc-p75 was localized in overexpressing strain (A) and in complemented negative mutant (B) with monoclonal antibody directed against Strep-tag as first antibody.</p

    Phenotype comparison between wild type <i>L. casei</i> BL23, Lc-p75-negative mutant and complemented Lc-p75 mutant.

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    <p>Pictures of wild type <i>L. casei</i> (A, C, F, H), Lc-p75-negative mutant (B, D, I) and complemented Lc-p75 mutant (E). Colony morphology (A, B), phase contrast microscopy (C, D, E) fluorescence microscopy with merged FM-4-64 (red) and DAPI (blue) staining (F, G) and transmission electron microscopy (H, I).</p

    Lc-p75 activity on purified muropeptides selected as substrates.

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    a<p>Di, disaccharide dipeptide; Tri, disaccharide tripeptide (L-Ala-D-iGln-L-Lys); Tetra, disaccharide tetrapeptide (L-Ala-D-iGln-L-Lys-D-Ala); Disaccharide, GlcNAc-MurNAc; iGln, isoglutamine; N, Asn; Ac, acetylation on MurNAc.</p>b<p>Similar amounts of each muropeptide were used for each test.</p>c<p>Percentage of each peak was calculated as the ratio of the peak area over the sum of areas of all the peaks identified in the corresponding chromatogram.</p>d<p>Other forms of muropeptides resulting from partial digestion of the substrate.</p

    AFM force spectroscopy for the wild-type TIL448 and the plasmid-cured derivative TIL1230.

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    <p>(A, D) Representative SEM images of <i>L. lactis</i> bacterial cells immobilized onto AFM tip and cantilever; (B, E) histograms of adhesion forces and (C, F) typical force-distance curves obtained when probing interactions between the wild-type TIL448 (A, B, C) and the plasmid-cured derivative TIL1230 (D, E, F) and PGM-coated polystyrene using AFM force spectroscopy in milliQ-grade water. One representative experiment (1024 force curves) is shown.</p
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