The attachment of a marine pseudomonad to polystyrene was found to be dependent upon (a) culture concentration, (b) the time allowed for attachment, (c) the growth phase of the culture, and (d) temperature. The number of attached cells increased with both culture concentration and the time allowed for attachment, until the attachment surface approached saturation. The number of cells which attached and the rate of attachment was greatest with log-phase cultures, and progressively decreased with stationary and death-phase cultures. A temperature of 3 °C ± 1 noticeably decreased the proportion of stationary phase cells which attached, compared with cells at 20 °C ± 1. These results can be described by a model based on physicochemical adsorption, which suggests that non-biological processes may play a major role in the initial events of bacterial adhesion.

The distribution of positions in the CGR plane were shown to be a generalization of Markov chain probability tables that accommodates non-integer orders. Therefore, Markov models are particular cases of CGR models rather than the reverse, as currently accepted. In addition, the CGR generalization has both practical (computational efficiency) and fundamental (scale independence) advantages. These results are illustrated by using Escherichia coli K-12 as a test data-set, in particular, the genes thrA, thrB and thrC of the threonine operon.

S U M M A R YStaining a marine bacterium with Ruthenium Red and Alcian Blue demonstrated an extracellular, compact acidic polysaccharide layer, which was involved in bacterial adhesion to surfaces. The adhesive substance was present on suspended bacteria and appeared to assist adhesion when they were forced into contact with a suitable surface. Bacteria, which had attached to a surface naturally, produced a secondary fibrous acidic polysaccharide, which probably developed from the primary polysaccharide, and could eventually replace it.A high pH in the growth medium almost totally prevented the appearance of primary polysaccharide in preparations of naturally attached bacteria, which were surrounded by the reticular secondary polysaccharide, and adhesion was not impaired. In contrast to naturally attached bacteria, those forcibly attached were surrounded by primary polysaccharide.High temperature lowered the number of bacteria attached, relative to culture density, but did not affect the appearance of the adhesive substance.

The attachment of a marine Pseudomonas sp. to a variety of surfaces was investigated, and the number of bacteria which became attached was related to the surface charge and degree of hydrophobicity of the substratum. Large numbers of bacteria attached to hydrophobic plastics with little or no surface charge [Teflon, polyethylene, polystyrene, poly(ethylene terephthalate)]; moderate numbers attached to hydrophilic metals with a positive (platinum) or neutral (germanium) surface charge; and very few attached to hydrophilic, negatively charged substrata (glass, mica, oxidized plastics). The results suggest that both electrostatic and hydrophobic interactions are involved in bacterial attachment.