Distinctive characters: By catalytic ac- of even minute traces of ferrous iron medium tion, this species increases by several fold to an acid thiosulfate medium may cause the amount of sulfuric acid normally formed decomposition of the thiosulfate, evidenced by the atmospheric oxidation of pyritic by the development of turbidity due to the materials found in bituminous coal seams formation of colloidal sulfur; this purely and associated rock strata. chemical reaction involving thiosulfate maj^ easily be misinterpreted as a bacterial oxidation of this same substrate. Source: Isolated from bituminous coal Comment: This organism closely resem bles Thiobacillus ferrooxidans and may, in fact, be identical with it. However Temple and Colmer (Jour. Bact., 59, 1950, 317) report that Thiobacillus ferrooxidans oxi- "^^^« drainages and from waters receiving dizes thiosulfate while Leathen and Braley ^^^^ discharges. (op. cit., 1954, 44) report that Ferrobacillus Habitat: Indigenous to bituminous coal ferrooxidans does not oxidize thiosulfate. regions. Frequently form relatively hard Thelatter workers (personal communication, granules of ferric iron in which many May, 1954) further report that the transfer bacteria are entrapped.
FAMILY VII. SPIRILLACEAE MIGULA, 1894.
{{c|(Migula, Arb. Bact. Inst. Karlsruhe, 1, 1894, 237; Spirillobacteriaceae Orla-Jensen, Jour. Bact., 6, 1921, 264.)
Spi.ril.la'ce.ae. M.L. neut.n. Spirillum type genus of the family; -aceae ending to denote a family; M.L. fem.pl.n. Spirillaceae the Spirillum family.
Cells simple, curved or spirally twisted rods. These frequently remain attached to each other after transverse division to form chains of spirally twisted cells. Cells are rigid and usually motile by means of a single flagellum (rarely two) or a tuft of polar flagella. Gram-negative. Frequently oxidative in their physiology. Aerobic or facultatively anaerobic, although a few strict anaerobes occur among the vibrios (Desulfovibrio and Vibrio). Largely water forms, although some are parasitic or pathogenic on higher animals and man.
Key to the genera of family 'Spirillaceae.
I. Curved, vibrio-like rods that are rarely united into a complete ring.
- A. Cells curved; rods never united at the end into a ring-shaped cell. Usually possess a single, polar flagellum.
- 1. Curved rods that are not known to attack cellulose.
- a. Aerobic to anaerobic, heterotrophic vibrios.
Genus I. Vibrio, p. 229.
- aa. Anaerobic, facultatively autotrophic vibrios that produce hydrogen sulfide or methane.
- b. Reduce sulfates to hydrogen sulfide.
Genus II. Desulfovibrio, p. 248.
- bb. Reduce carbon dioxide to methane.
Genus III. Methanobacterium, p. 250.
- 2. Curved rods that attack cellulose.
- a. Vibrio-like cells.
Genus IV. Cellvibrio, p. 250.
- aa. Pointed, sickle-shaped cells.
Genus V. Cellfalcicula, p. 252.
- B. Curved rods that join ends to form a complete ring.
Genus VI. Microcyclus, p. 253.
