{
  "abstract": "Background and Aims: The chlorophycean seaweed genus Ulva (sea lettuce and relatives) possesses cellulose and cell-wall-matrix polysaccharides operationally classified as ‘pectin-like’ (hot-water-extractable anionic ulvans and glucuronans) and hemicelluloses. Given that Ulva is only distantly related to streptophytes (land-plants plus charophytic algae), their wall polysaccharides are likely to diverge significantly. We therefore explored the little-known structure and properties of Ulva hemicellulose.\n\nMethods: Hemicellulose b was alkali-extracted from hot-oxalate-pretreated Ulva linza alcohol-insoluble residue, then digested with endo-β-xylanase, Driselase or endo-cellulase, yielding several oligosaccharides. These were separated by size on gel-permeation and preparative paper chromatography. Oligosaccharides were dissected by acid hydrolysis, glycosidase digestion and alkaline peeling; products were analysed by thin-layer chromatography. Purified oligosaccharides were also characterized by nuclear magnetic resonance (NMR) spectroscopy.\n\nKey Results: Thirteen di- to pentasaccharides were purified. On acid hydrolysis, they yielded only xylose (Xyl) and/or glucose (Glc). Each was digestible by either β-xylosidase or β-glucosidase, identifying the non-reducing terminus as β-Xyl or β-Glc, respectively. The rate of alkaline peeling, which attacks progressively from the reducing terminus, indicated (1→4) linkages; in each case, the smallest peeling product (i.e. originally the non-reducing terminus) was either Xyl or Glc, concurring with the glycosidase digestion result. Structures were deduced [β-(1→4)-linked Xyl-Xyl, Xyl-Xyl-Xyl, Xyl-Glc, Xyl-Xyl-Glc, Xyl-Xyl-Xyl-Glc, Glc-Glc, Glc-Xyl-Xyl, Glc-Glc-Xyl-Xyl and Xyl-Glc-Glc-Xyl-Xyl] and validated by NMR spectroscopy. Unexpectedly, NMR showed one oligosaccharide to be Glc-3-Glc-4-Glc, with the (1→3)-bond probably arising artefactually by trans-β-glucanase activity of the cellulase. Ulva hemicellulose hydrogen-bonded to cellulose more rapidly than any tested land-plant polysaccharide.\n\nConclusions: The major hemicellulose of Ulva is a β-(1→4)-linked linear polysaccharide of Xyl and Glc, which we term phycoxyloglucan. The backbone has runs of up to three contiguous β-Xyl and three contiguous β-Glc residues, thus differing fundamentally from land-plant xyloglucan. Its structure confers high affinity for cellulose, suggesting potential biotechnological applications for this seaweed and contributing to the mechanical properties of the cell wall.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "name": "Marie N Rapin"
    },
    {
      "name": "Lorna Murray"
    },
    {
      "name": "John H Bothwell"
    },
    {
      "name": "Ian H Sadler"
    },
    {
      "name": "Stephen C Fry"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1gnfv021dfd0z.bib",
  "cited_by": 0,
  "doi": "10.1093/aob/mcag195",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13715020/",
  "id": "1gnfv021dfd0z",
  "issns": [
    "0305-7364",
    "1095-8290"
  ],
  "landing_url": "https://doi.org/10.1093/aob/mcag195",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "AcademicSubjects/SCI01080"
    ],
    [
      "heading",
      "AcademicSubjects/SCI01130"
    ],
    [
      "heading",
      "AcademicSubjects/SCI01210"
    ],
    [
      "heading",
      "Original Article"
    ],
    [
      "openalex",
      "1110|Polysaccharides and Plant Cell Walls"
    ]
  ],
  "openalex": "W7169572699",
  "pdf_url": null,
  "pmcid": "PMC13715020",
  "pmid": "42464775",
  "published": "2026-07-17",
  "publisher": "Oxford University Press",
  "ris": "https://research.draconitic.com/paper/1gnfv021dfd0z.ris",
  "sources": [
    {
      "first_seen": "2026-11-01T12:22:24Z",
      "native_id": "PMC13715020",
      "source": "pmc",
      "url": "https://doi.org/10.1093/aob/mcag195"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1110|Polysaccharides and Plant Cell Walls",
      "subfield": "plant-biology"
    }
  ],
  "title": "Linear phycoxyloglucan with oligo-xylose domains in the green seaweed Ulva: a unique hemicellulose",
  "title_text": "Linear phycoxyloglucan with oligo-xylose domains in the green seaweed Ulva: a unique hemicellulose",
  "type": "peer-reviewed",
  "updated_at": "2026-11-01T12:22:24Z",
  "url": "https://research.draconitic.com/paper/1gnfv021dfd0z",
  "venue": "Annals of Botany",
  "versions": []
}