EVIDENCE FOR THE ADHESIVE FUNCTION OF THE EXOPOLYSACCHARIDE OF HYPHOMONAS STRAIN MHS-3 IN ITS ATTACHMENT TO SURFACES

Hyphomonas strain MHS-3 (MHS-3) is a marine procaryote with a biphasic life cycle and which has prosthecate stages that adhere to submerged substrata. We found that adherent forms produced an exopolysaccharide (EPS) capsule that bound Glycine max lectin, Arachis hypogaea lectin, and Bauhinia purpurea lectin (BPA), each having affinity for N-acetyl- D-galactosamine. It also bound the dye Calcofluor. BPA and Calcofluor were tested for the ability to hinder MHS-3 adhesion to glass surfaces ; they reduced attachment by >50 and >85%, respectively. Periodate tre atment also reduced attachment (by >80%), but pronase treatment did no t. Furthermore, an EPS(-) variant, Hyphomonas strain MHS-3 rad, did no t attach well to surfaces. These results suggest that the MHS-3 EPS ca psule is an adhesin.