| Morphology | Gallionella ferrunginea |
| CELLULAR |
| Staining | Gram-negative |
| Morphology | Cells (fully developed) kidney-shaped, 0.5-0.7 um in diameter and 0.8-1.8 um in length; daughter cells rounded immediately after fission |
| Motility | Cells motile by means of a single polar flagellum when dislodged from a stalk (naturally liberated as swarmer cells or artificially liberated |
| Specialized structures | Cells grown in ferrous iron-containing natural waters or mineral media secrete colloidal ferric hydroxide from the concave side without any organic matrix, forming twisted (periphytic community) or nontwisted (pelagic community) inorganic stalks 0.3-0.5 um in width (primary stalks) and up to 400 um in length. Stalks consist of a bundle of numerous fibers each about 2 nm in thickness at the point of excretion by the cell. Stalk fibers and stalks dissolve completely in reducing agents and weak acids (therefore, there is no similarity to flagella tufts of Selenomonas species). Cells always lie apically at the tip of the stalk, with the long axis of the cell perpendicular to the long axis of the stalk. Multiplication by transverse binary fission, and continuous stalk production during cell fission results in dichotomous branching of the stalks. Rotary motion of the apical cell causes stalk twisting. Capsules not formed. Endospores not formed.. by dissolving the stalks in reducing agents). Intracytoplasmic membranes from membrane vesicles and long vesicotubular channels into the central region of the cell, predominantly starting from an invagination of the cytoplasmic membrane of the concave cell side. All membranes are exceptionally thin (only 4-5 nm thick) but show typical structures of Gram-negative bacteria, i.e. two dense layers separated by an electron-transparent region; cell envelope totally developed with inner and outer membrane and peptidoglycan (i.e. not like mycoplasmas). Poly-B- hydroxybutyrate (PHB) and glycogenlike granules are formed as storage inclusions. |
| Division |
| COLONIAL |
| Solid surface |
| Liquid |
| Growth Parameters | Gallionella ferrunginea |
| PHYSIOLOGICAL |
| Tropism | Chemolithotrophic and chemoautotrophic |
| Oxygen | Strictly aerobic (microaerobic). low O2 content of about 1%, |
| pH | |
| Temperature | low temperature of about 17`C |
| Requirements | Only ferrous iron ions as electron donor and CO2 as carbon source in almost neutral mineral medium are required for growth. Organisms do not oxidize manganous ions |
| Products | |
| Enzymes | CO2 fixation via the enzymes of the Calvin cycle, i.e. D-ribulose-1,5-bisphosphate carboxylase (RuBPCase), present in the cytosol (carboxysomes do not occur), and D- ribulose-5-phosphate kinase |
| Unique features | Cultural characteristics
(low redox potential with an Eh ranging from + 200 to +
320 mV, , Fe (II) of 5- 25 mg/l and CO2 of about 150 or
more mg/l are optimum batch culture conditions. Depend on the stability conditions of bivalent ionic iron at a pH near 6... Under lithoautotrophic conditions, batch culture growth yield (dry weight) (Yfe) per g atom Fe (II) oxidized was found to be 0.36 g x g atom-1, indicating the same energy metabolism as known for Thiobacillus ferrooxidans with a consumption of about 150 g ferrous iron per g dry weight. |
| ENVIRONMENTAL |
| Habitat | Organisms occur most abundantly in oligotrophic ferrous iron- bearing waters (freshwater or marine habitats); have also been found in the metalimnion of a eutrophic lake. |
| Lifestyle | |
| Pathogenicity |
| Distribution |
| Genome | Gallionella ferrunginea |
| G+C Mol % | 54.6 (Bd, Gallionella ferruginea strain BD). |
| Reference | Gallionella ferrunginea |
| First citation | Ehrenberg, C.G. 1838. Die Infusionsthierchen als volkommene Organismen. L. Voss, Leipzig. |
| The Prokaryotes | |
| Bergey's Systematatic | p 1974 H.H. Hanert |
| Bergey's Determinative | p 467 |
| References |
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