Fine Structure of Thiobacillus thiooxidans

Abstract

Mahoney, Robert P. (Skidmore College, Saratoga Springs, N.Y.), and Mercedes R. Edwards . Fine structure of Thiobacillus thiooxidans . J. Bacteriol. 92: 487–495. 1966.—Thin section analysis of the chemosynthetic autotroph Thiobacillus thiooxidans revealed structures comparable to gram-negative heterotrophic bacteria. Although this species is unique in that it oxidizes elemental sulfur for energy, uses carbon dioxide as its sole source of carbon, and can withstand a p H of less than 1, thin sections revealed a profile of the cell envelope (cell wall and plasmalemma) similar to other gram-negative species which have more common physiological traits. The cell wall is composed of five layers with an overall width of approximately 200 A, and the plasmalemma appears as a conventional “unit membrane” with a width of about 85 A. Volutin granules and less-dense bodies of similar shape and size were frequently observed in close association with the nucleoplasm. The nature and function of these bodies are unknown at this time.