Hyphomonas spp., Shewanella spp., and Other Marine Bacteria Lack Heterogeneous (Ladderlike) Lipopolysaccharides.

The lipopolysaccharides (LPS) of 19 marine bacteria were examined for size heterogeneities by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis in conjunction with an LPS-specific silver staining method. Fifteen marine bacteria had an R-type LPS instead of the ladderlike LPS array characteristic of most bacteria. In addition, three marine bacteria also had a single large LPS molecule. Without constraints (e.g., surface masking), R-type LPS, a more hydrophobic molecule, predominates in Shewanella and Hyphomonas species and in other marine bacteria.