ULTRASTRUCTURE OF GAS BALLOONS AND SURFACE-FILMS IN COLONIES OF THE GRAM-NEGATIVE BACTERIUM ALCALIGENES SP D(2)

The surface film (SF) on colonies of Alcaligenes sp. d(2) has a comple x bipolar structure: its outer layer is hydrophobic and smooth (''stru ctureless''), while its inner layer, contacting the aqueous phase, is hydrophilic and has a rough, wrinkled, granular-fibrillar structure. T he walls of extracellular gas balloons (EGBs) have a similar bipolar s tructure. The hydrophobic layer of SFs and EGBs, which contacts the ga seous phase, virtually cannot be revealed in thin sections; it is appa rently degraded during treatment with solvents (acetone) and resins ev en at low temperatures (-80 and -35 degrees C, respectively). In space s between the cells attached to the hydrophobic surface of EGBs and SF s, hemosomes (HS) are formed; these consist of membrane vesicles and t ubular rod-shaped structures and are red in color due to protoporphyri n IX and hemoproteins, which were revealed by cytochemical staining.