Adhesive Properties of a Symbiotic Bacterium from a Wood-Boring Marine Shipworm

Abstract

Adhesive properties of a cellulolytic, nitrogen-fixing bacterium isolated from a marine shipworm by Waterbury et al. (J. B. Waterbury, C. B. Calloway, and R. D. Turner, Science 221:1401-1403, 1983) are described. 35 S-labeled cells of the shipworm bacterium bound preferentially to Whatman no. 1 cellulose filter paper, compared with its binding to other cellulose substrata or substrata lacking cellulose. The ability of the bacteria to bind to Whatman no. 1 filter paper was significantly reduced by glutaraldehyde or heat treatment of cells. Pretreatment of cells with azide, valinomycin, gramicidin-D, bis-hexafluoroacetylacetone (1799), or carbonyl cyanide- p -trifluoromethoxyphenylhydrazone inhibited adhesion activity. Cells pretreated with pronase or trypsin also exhibited reduced binding activity, but chymotrypsin and peptidase had no effect on adhesion activity. Cellodextrins and methyl cellulose 15 inhibited the adhesion of shipworm bacteria to filter paper, whereas glucose, cellobiose, and soluble carboxymethyl cellulose had no significant effect. The divalent cation chelators EDTA and EGTA [ethylene glycol-bis(β-aminoethyl ether)- N,N,N′N′ -tetraacetic acid] had little or no effect on adhesive properties of shipworm bacteria. Also, preabsorbing the substratum with extracellular endoglucanase isolated from the shipworm bacterium or 1% bovine serum albumin had no apparent effect on bacterial binding. Low concentrations (0.01%) of sodium dodecyl sulfate solubilized a fraction from whole cells, which appeared to be involved in cellular binding activity. After removal of sodium dodecyl sulfate, several proteins in this fraction associated with intact cells. These cells exhibited up to 50% enhanced binding to filter paper in comparison to cells which had not been exposed to the sodium dodecyl sulfate-solubilized fraction.