A genus of bacteria not assigned to any taxonomic family. The cells are Gram-negative, rod-shaped, and often motile with a single flagellum at one end. Energy is obtained by the oxidation of sulphur or sulphur-containing compounds, e.g. sulphide and thiosulphate. Most species require the presence of air for growth. There are several species, found in soil, marine and freshwater environments, acidic mine waters, hot sulphur springs, etc.
Subjects: Plant Sciences and Forestry.