The Chemical Entities of Biological Interest (ChEBI) ontology is downloaded weekly from EMBL-EBI at http://www.ebi.ac.uk/chebi/. The data is made available under the Creative Commons License (CC BY 3.0, http://creativecommons.org/licenses/by/3.0/). For more information see: Degtyarenko et al. (2008) ChEBI: a database and ontology for chemical entities of biological interest. Nucleic Acids Res. 36, D344–D350.
A (1->4)-beta-D-glucan consisting of elementary cellulose fibrils or their bundles, whose diameter lies typically in the range of 20-40 nm, but may be as small as 3-10 nm. The fibrils can exceed 1 mum in length.