Summary: Forty-five strains classified in the family Neisseriaceae were analysed for wax esters by gas—liquid chromatography. The amounts and types of waxes varied between the taxa. Waxes were not detected in 16 strains of ‘true neisseriae’ (genus Neisseria) or in two strains of Kingella, but they were found in all ‘false neisseriae’, in all species of Moraxella except Moraxella phenylpyrouvica, in five out of 10 strains of Acinetobacter, and in all strains of a group of psychrophilic, oxidase-positive organisms. The chain lengths of the wax esters ranged from C24 to C42, with C36 predominating. In all taxa, esters with even numbers of carbon atoms constituted 70 to 100% of the total. Saturated, mono-unsaturated and di-unsaturated waxes were found. Acinetobacter strains were characterized by large amounts (30 to 98%) of di-unsaturated wax esters; such waxes did not exceed 8% in the ‘false neisseriae’ or Moraxella spp. Waxes of strains belonging to the psychrophilic, oxidase-positive group generally resembled those found in Moraxella. Wax esters with odd numbers of carbon atoms were abundant in M. lacunata (29%), M. atlantae (15%) and in the psychrophilic group (19 to 28%); long-chain esters (C40 or above) were characteristic of M. atlantae (30%) and one strain of M. osloensis (26%).
Summary: Zoospores of Phytophthora palmivora were induced to encyst synchronously and changes in morphology, particularly in surface structure, were examined by freeze-fracture and freeze-etching techniques.
A uniform ‘fuzzy coat’, 20 to 25 nm thick, covers the plasma membrane. This hitherto unknown structure surrounds the entire zoospore body and flagella. No structural correspondence between cyst wall microfibrils and plasma membrane particles was found. The pattern of distribution of plasma membrane particles remains unchanged during encystment.