Species specificity of O-linked carbohydrate chains of the oviducal mucins in amphibians: structural analysis of neutral oligosaccharide alditols released by reductive β-elimination from the egg-jelly coats of Rana clamitans

2002 ◽  
Vol 363 (3) ◽  
pp. 457-471 ◽  
Author(s):  
Florence DELPLACE ◽  
Emmanuel MAES ◽  
Jérôme LEMOINE ◽  
Gérard STRECKER

The extracellular matrix (the so-called jelly coat) surrounding amphibian eggs mainly comprises highly O-glycosylated proteins. These oviducal mucins have an important role in the fertilization process, and their carbohydrate chains are remarkably species-specific. Alkaline reductive treatment of the jelly-coat material of the frog Rana clamitans led to the release of oligosaccharide alditols. The neutral oligosaccharide alditols were fractionated and purified by successive chromatographic techniques. The structures of 27 of them, ranging from three to sixteen monosaccharides, were established by a combination of NMR spectroscopy, methylation analyses and matrix-assisted laser-desorption ionization—time of flight MS. Typically, some of the neutral compounds appeared to possess the core structure: Gal(β1–3)[GlcNAc(β1–6)]Gal(β1–3)[GlcNAc(β1–6)]GalNAc-ol (where GalNAc-ol represents N-acetylgalactosaminitol). Moreover, a novel type of chain termination, characterized by an unusual sequence {Fuc(α1–2)Gal(α1–3)Gal(α1–4)Gal(β1–3/4)} was observed. Indeed, the most complex representative structure of this series was found to be: Fuc(α1–2)Gal(α1–3)Gal(α1–4)Gal(β1–3)[Fuc(α1–2)Gal(α1–3)Gal(α1–4)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–3)[Fuc(α1–2)Gal(α1–3)Gal(α1–4)Gal(β1–4)GlcNAc(β1–6)]GalNAc-ol.

2020 ◽  
Vol 9 (1) ◽  
pp. 82
Author(s):  
Issa Sy ◽  
Lena Margardt ◽  
Emmanuel O. Ngbede ◽  
Mohammed I. Adah ◽  
Saheed T. Yusuf ◽  
...  

Fascioliasis is a neglected trematode infection caused by Fasciola gigantica and Fasciola hepatica. Routine diagnosis of fascioliasis relies on macroscopic identification of adult worms in liver tissue of slaughtered animals, and microscopic detection of eggs in fecal samples of animals and humans. However, the diagnostic accuracy of morphological techniques and stool microscopy is low. Molecular diagnostics (e.g., polymerase chain reaction (PCR)) are more reliable, but these techniques are not routinely available in clinical microbiology laboratories. Matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a widely-used technique for identification of bacteria and fungi; yet, standardized protocols and databases for parasite detection need to be developed. The purpose of this study was to develop and validate an in-house database for Fasciola species-specific identification. To achieve this goal, the posterior parts of seven adult F. gigantica and one adult F. hepatica were processed and subjected to MALDI-TOF MS to create main spectra profiles (MSPs). Repeatability and reproducibility tests were performed to develop the database. A principal component analysis revealed significant differences between the spectra of F. gigantica and F. hepatica. Subsequently, 78 Fasciola samples were analyzed by MALDI-TOF MS using the previously developed database, out of which 98.7% (n = 74) and 100% (n = 3) were correctly identified as F. gigantica and F. hepatica, respectively. Log score values ranged between 1.73 and 2.23, thus indicating a reliable identification. We conclude that MALDI-TOF MS can provide species-specific identification of medically relevant liver flukes.


1998 ◽  
Vol 330 (1) ◽  
pp. 469-478 ◽  
Author(s):  
Willy MORELLE ◽  
Gérard STRECKER

Egg jelly coats from Rana utricularia are formed by components secreted along the oviduct. These secretion products overlay the oocytes as they pass along the different oviducal portions. In this study, carbohydrate chains of the jelly coat surrounding the eggs of R. utricularia were released by alkali/borohydride treatment. Fractionation of O-linked oligosaccharide-alditols was achieved by a combination of chromatographic techniques comprising anion-exchange chromatography, gel-permeation chromatography and HPLC on a silica column bonded with aminopropyl groups. Structural characterization was performed by one- and two-dimensional 1H-NMR spectroscopy in combination with matrix-assisted laser-desorption ionization-time of flight MS and methylation analysis. Ten oligosaccharide structures possessing a core consisting of Galβ(1 → 3)GalNAc-ol with or without branching through a GlcNAc residue linked β(1 → 6) to the GalNAc residue (core type 2 or core type 1 respectively) are described. The most representative carbohydrate sequences are: GlcNAc(β1-3)[Fuc(α1-4)]GlcNAc, GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc(β1-3)GlcNAc and Gal(β1-3)GlcNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc. The carbohydrate chains isolated from R. utricularia are quite different from those found in other amphibian species, in which the presence of species-specific material has been characterized. Since the jellies surrounding amphibian eggs are involved in egg-sperm interactions, these structural investigations can provide biochemical support for investigation of the fertilization process.


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