The Sheathed Flagellum of Pseudomonas stizolobii

Abstract

Organisms of two strains of Pseudomonas stizolobii possessed one polar flagellum of unusual thickness. Negative-contrast staining and ultrathin sectioning indicated that the flagella are sheathed and are comparable in structure to the sheathed flagella described in Vibrio and Bdellovibrio. In some instances, flagella displayed sheath and core structure after negative constrast staining. Distal 'tubules ' and ' knobs ' apparently consisting entirely of sheath material were also seen. The thickness of the sheath, which in section consisted of an outer dense component and an inner lighter component, was similar to that of the outer double track membrane of the cell wall. I N T R O D U C T I O NDuring the examination of a collection of species of Pseudomonas for the presence of fimbria-like appendages (Fuerst & Hayward, 1969), unusual polar flagella were seen on Pseudomonas stizolobii (Wolf) Stapp, 1935. This species is a plant pathogen causing a disease of the leaves and stems of mainly leguminous plants (Burkholder, 1957;Rothwell & Hayward, 1964). Whereas flagella of most bacteria are 120 to 150 A in diameter and, under the electron microscope at high resolution, preparations of negatively stained material exhibit a helical aggregate of globular subunits, (Joys, 1968 ;Doetsch & Hageage, 1968), the flagella of P. stizolobii were of greater thickness and lacked the substructure characteristic of unsheathed bacterial flagella. Our aim was to determine by electron microscopic techniques the nature of the flagellum of P. stizolobii and to compare it with the sheathed flagella which are known to occur in a very few genera of Gram-positive and Gram-negative bacteria. Organisms not to be treated with reagents were carried through two 72 hr serial subcultures in Craigie tubes of motility medium and 5 or 8 serial subcultures of variable duration in 6 x 3 in., tubes containing 5 ml. peptone yeast extract broth.Organisms to be treated with various reagents (including distilled water controls) were

Unusual Cellular Fatty Acids and Distinctive Ultrastructure in a New Spiral Bacterium (Campylobacter Pyloridis) from the Human Gastric Mucosa

“…Absence of flagellar sheathing has, indeed, been advanced in support of the generic separation of campylobacters from the genus Vibrio (McCoy et al, 1975). In contrast, sheathed flagella are amply documented in Vibrio (Follett and Gordon, 1963;Glauert et al, 1963), pseudomonads (Fuerst and Hayward, 1969), and Spirillum (Lockard and Boler, 1968). Terminal bulbs similar to those of C. pyloridis have also been noted on the sheathed flagella of V. cholerae (Rowles et al, 1976).…”

The Attachment of Bacteria to the Surfaces of Animal Cells

“…The apparent rigidity of B. pertussis fimbrial fragments and of the fimbriae of other enterobacteria may indicate a subunit organization in these fimbriae similar to that proposed for type 1 fimbriae of E. coli. Fuerst and Hayward (1969) proposed a similar helical structure for the fIlamentous appendages of pseudomonads. Structurally, the C renale adhesin and K88 appear to be quite different from type 1 fimbriae.…”

Surface Appendages Similar to Fimbriae (Pili) on Pseudomonas Species

“…Sheathed flagella were found only on strains of P. stizolobii (Fuerst & Hayward, 1969). Where substructure of unsheathed flagella was visible, it usually consisted of an aggregate of globular subunits (e.g.…”