Recognition intensities of submolecular structures, mammalian glyco-structural units, ligand cluster and polyvalency in abrin-a-carbohydrate interactions.

Abrin-a is the most toxic fraction of lectins isolated from Abrus precatorius seeds and belongs to the family of type 2 ribosome inactivating proteins (RIP). This toxin may act as a defense molecule in plants against viruses, fungi and insects, where attachment of abrin-a to the exposed glycans on the surface of target cells is the crucial and initial step of its cytotoxicity. Although it has been studied for over four decades, the recognition factors involved in abrin-a-carbohydrate interaction remains to be clarified.

Roles of mammalian structural units, ligand cluster and polyvalency in the Abrus precatorius agglutinin and glycoprotein recognition process.

Previous studies on one of the toxic type 2 ribosome inactivating proteins (RIP), Abrus precatorius agglutinin (APA), have shown that the recognition domains of APA are restricted to monomers of Galbeta1-3GalNAc (T, Thomsen-Friedenreich glycotope) and Galbeta1-3/4GlcNAc (blood group precursor type I/II sequences); which are essential but play a minor role in the recognition process. In this study, APA recognition factors were expanded to include ligand clusters and polyvalent glycotopes by enzyme-linked lectinosorbent binding and inhibition assays. Based on the results of molar relative potency, the essential mammalian structural units are Galbeta1-3GalNAcalpha/beta1- (T(alpha)/T(beta))>Galalpha1-4Gal (E)>Galbeta1-3/4GlcNAc (I/II) and avidity for tri-/di-antennary II(beta), T, E and II monomers was found to be 7.

Development and application of a new scheme for typing Campylobacter jejuni and Campylobacter coli by PCR-based restriction fragment length polymorphism analysis.

A molecular typing approach for Campylobacter jejuni and Campylobacter coli was developed with restriction fragment length polymorphism analysis of a 9.6-kb PCR-amplified portion of the lipopolysaccharide gene cluster. Sixty-one Penner serotype reference strains were analyzed with this new genotyping scheme, and 32 genogroups were found.