Gal.li.o.nel' la
. M.L. dim. ending ‐
ella
; M.L. fem. n.
Gallionella
named for B. Gaillon, a customs agent and zoologist (1782–1839) in Dieppe, France.
Proteobacteria / Betaproteobacteria / Nitrosomonadales / Gallionellaceae / Gallionella
Gram‐negative,
bean‐shaped cells
, usually 0.5–0.8 × 1.6–2.5 µm, that secrete an extracellular
twisted stalk
from the concave side, 0.3–0.5 µm in width and up to 400 µm or more in length. The stalk is composed of numerous 2 nm‐wide fibers and is produced under microaerophilic conditions when cells are in late exponential or stationary growth phase. Motile by means of a polar flagellum.
Microaerophilic; chemolithotrophic growth
can be obtained
in vitro
using oxygen and ferrous iron concentration gradients in a salt medium with
CO
2
as sole carbon source
(Table BXII.β.108).
Mixotrophic metabolism
has been demonstrated with glucose, fructose, and sucrose. Can be found where anaerobic
groundwater with ferrous iron
reaches an oxygen‐containing environment. Belongs to the
Betaproteobacteria
, family
Gallionellaceae
, with one known species,
G. ferruginea
. Most closely related species according to 16S rDNA sequence analysis is the chemolithotroph
Nitrosospira multiformis
, distantly related with a 16S rDNA sequence similarity of 90%.
The mol
%
G
+
C of the DNA is
: 51–54.6 (Hanert, 1989).
Type species
:
Gallionella ferruginea
Ehrenberg 1838, 166.