Comparative Ultrastructure of the Thiobacilli

Abstract

The ultrastructure of seven Thiobacillus species was studied. The structure of their cell envelopes is similar, if not identical, to that found in other gram-negative bacteria. Obvious differences were noted in the middle layer of the cell envelope of the seven cultures. Polyhedral inclusion bodies were apparent in four of the organisms: T. thioparus, T. neapolitanus, T. intermedius, and T. thiooxidans. Lamellar bodies, similar to those present in certain photosynthetic bacteria were found in a few cells of T. thioparus. Structures resembling mesosomes were discovered in T. dinitrificans. A few cells of T. intermedius possessed paracrystalline bodies. Other inclusions, probably volutin and polysaccharide, were present in some of the cultures.