Oral Lesions in Neurofibromatosis Type I: Report of a Case and Clinical Implications.

Neurofi broma is a benign peripheral nerve sheath tumor and one of the most frequent tumors of neural origin. Its presence is one of the main clinical criteria for the diagnosis of neurofi bromatosis Type I (NF-I). NF-I is a hereditary disorder inherited as an autosomal dominant trait and the patients present with skin lesions, i.e., café au lait spots and neurofi bromas. Diagnosis is mainly based on a series of clinical criteria. NF-I may present with defi nite oral lesions, which mandate the dental surgeons with the responsibility of accurate diagnosis. Th e paper emphasizes the role of an oral diagnostician in the recognition of NF-I in a family.

Multiplicity of carbohydrate-binding sites in beta-prism fold lectins: occurrence and possible evolutionary implications.

The beta-prism II fold lectins of known structure, all from monocots, invariably have three carbohydrate-binding sites in each subunit/domain. Until recently, beta-prism I fold lectins of known structure were all from dicots and they exhibited one carbohydrate-binding site per subunit/domain. However, the recently determined structure of the beta-prism fold I lectin from banana, a monocot, has two very similar carbohydrate-binding sites. This prompted a detailed analysis of all the sequences appropriate for two-lectin folds and which carry one or more relevant carbohydrate-binding motifs. The very recent observation of a beta-prism I fold lectin, griffthsin, with three binding sites in each domain further confirmed the need for such an analysis. The analysis demonstrates substantial diversity in the number of binding sites unrelated to the taxonomical position of the plant source. However, the number of binding sites and the symmetry within the sequence exhibit reasonable correlation. The distribution of the two families of beta-prism fold lectins among plants and the number of binding sites in them, appear to suggest that both of them arose through successive gene duplication, fusion and divergent evolution of the same primitive carbohydrate-binding motif involving a Greek key. Analysis with sequences in individual Greek keys as independent units lends further support to this conclusion.It would seem that the preponderance of three carbohydrate-binding sites per domain in monocot lectins, particularly those with the beta-prism II fold, is related to the role of plant lectins in defence.