Structural Properties and Features of Parasitic Bdellovibrio bacteriovorus

Abstract

The structure of five parasitic strains of Bdellovibrio bacteriovorus was studied by electron microscope after negative staining and in shadow-case and etched freezefractured preparations. Special attention was paid to the cell wall and the flagellar sheath which is continuous with the wall or part of it. These structural components reveal distinct features which are induced by certain staining substances; they are exceedingly susceptible to disruption by physical treatments, and in old cells often appear impaired. In freeze-fractured cells the wall shows characteristic fracturing tendencies not known in other microorganisms. These structural properties and features are distinct to Bdellovibrio wall and flagellar sheath, the structural integrity of which is a fundamental requirement for the infectivity and survival of this organism. The anterior end of Bdellovibrio is differentiated: 6 to 12 ring-like structures (9 to 12 nm, outer diameter) are built into its wall and several fibers (7 to 10 nm wide, up to 1.5 ,um long) emerge from it. Intracellular structures, which are revealed as compact oval bodies bulging from the cell border and have internal laminated organization, are characteristic of Bdellovibrio after negative staining with certain compounds. These findings on the structure of parasitic Bdellovibrio substantiate previous observations indicating the uniqueness of this organism and add criteria for the identification of this genus. Proc., p. 41, 1967). MATERIALS AND METHODS Organisms. Five strains of B. bacteriovorus were employed: 109 and D (obtained from M.

Isolation of Bdellovibrio bacteriovorus from a tropical wastewater treatment plant and predation of mixed species biofilms assembled by the native community members

“…However, the effects of other predatory organisms, such as predatory bacteria, are less understood. The Bdellovibrio ‐and‐like organisms (BALOs) are a specialized group of predatory bacteria, which are generally small (average size 0.2‐0.5 µm × 1.2‐1.5 µm), highly motile with a single sheathed polar flagellum with similar predation properties (Abram and Davis, ). The BALOs solely prey upon other Gram‐negative bacteria by attaching and penetrating into the periplasmic space of their prey bacteria, where the BALOs proliferate (Varon and Shilo, ).…”

Isolation and composition of sheathed flagella from Bdellovibrio bacteriovorus 109J

“…Proc., p. 41,1967) is in contrast to the constant periodicity exhibited by most other bacterial flagella. The exceptional thickness of the flagella is due to the presence of a flagellar sheath which encloses an inner core filament comparable in diameter and superficial appearance to unsheathed bacterial flagella (1,40,46). The sheath appears to be physically continuous with the cell outer membrane (4,40,45), but observations made by electron microscopy (1) suggest that the two domains may differ in composition.…”

Novel bacterium infecting an African snail

“…core. However, these flagella derive their sheath from the cell wall or outer membrane(1,5,17,19,29), and our preparations show no evidence of such a relationship. Neither the sheathed flagella nor the filaments of this new microorganism meet the definition of a prostheca(28).…”

“…The filaments, thicker than the 12-to 19-nm diameter of most bacterial flagella (2), in size and structure resemble the thick polar flagella of some vibrios (17,19), pseudomonads (18), and Bdellovibrio bacteriovorus (1,5,6,29)…”