FAMILY III. THIOBACTERIACEAE 



85 



cultures differ in appearance from Thio- 

 bacillus thioparus. Ferrous iron serves as a 

 sufficient energy source with the concomi- 

 tant formation of enormous quantities of 

 ferric ions in acid media where ferric iron is 

 not otherwise produced in quantity. The 

 lobed, iron-encrusted colony formed on 

 ferrous agar is unique. Cultures maintained 

 on ferrous media lose the ability to oxidize 

 thiosulfate, but colonies maintained on 

 thiosulfate media retain their iron-oxidiz- 

 ing capacity. 



Source: Isolated from bituminous coal 

 mine drainage waters which were strongly 

 acid and high in ferrous iron. Found in 

 West Virginia and Pennsylvania. 



Habitat : Acid waters of high iron content 

 including drainage from several types of 

 mines and soils containing pyrite or marca- 

 site. 



3. Thiobacillus novellus Starkey, 

 1934. (Jour. Bact., 28, 1934, 365; Jour. Gen. 

 Physiol., 18, 1935, 325; Soil Sci., 39, 1935, 

 207, 210.) 



no.vel'lus. L. dim. adj. novellus new. 



Short rods or ellipsoidal cells 0.4 to 0.8 

 by 0.6 to 1.8 microns. Non-motile. Gram- 

 negative. 



Gelatin stab: Mucoid growth at point of 

 inoculation. Sub-surface growth meager, 

 slow liquefaction. 



Agar plate : Growth slow, colorless, moist, 

 raised, circular, 1 mm in diameter. Deep 

 colonies tiny, lens-shaped. 



Thiosulfate agar plate: Growth slow, be- 

 coming white from precipitated sulfur. 

 Surface colonies small, circular, moist. 

 Crystals of CaS04 appear throughout the 

 agar. 



Agar slant: Growth fairly abundant, soft, 

 somewhat ropy, raised, shining, moderately 

 spreading; whitish in reflected light, brown- 

 ish opalescence in transmitted light. 



Thiosulfate agar slant: Growth very thin, 

 practically colorless. No sub-surface 

 growth. Sulfur usually precipitated as 

 white, frosty film on the surface. 



Agar stab : White to cream-colored growth 

 confined close to point of inoculation; pene- 

 trates to bottom of tube. 



Thiosulfate agar stab: No appreciable 

 surface growth. 



Broth: Slightly turbid. Gelatinous pel- 

 licle. Forms long, streamer-like network 

 extending from surface to the bottom. Some 

 sediment. 



Thiosulfate broth: Uniform turbidity. No 

 pellicle. Whitish sediment with thin, incom- 

 plete membrane on the bottom of the flask. 

 Reaction acid in a few days, changes pH 7.8 

 to 5.8 with decomposition of a small quantity 

 of thiosulfate. 



Sulfur solution medium of slightly alka- 

 line reaction: No growth. 



Potato slant: Growth limited, cream- 

 colored, moist, shining, slightly brown. 



Litmus milk: Slow development of slight 

 alkalinity. 



Facultatively autotrophic. 



Optimum reaction: Close to neutrality 

 (limiting reactions, pH 5.0 to 9.0). 



Aerobic. 



Distinctive characters: Oxidizes thiosul- 

 fate to sulfate and sulfuric acid. Does not 

 oxidize free sulfur. 



Source: Isolated from soils. 



Habitat: Soils. 



4. Thiobacillus coproliticus Lipman 

 and McLees, 1940. (Soil Sci., 50, 1940, 432.) 



co.pro.Iit'i.cus. Gr. noun coprus dung; 

 Gr. noun lithus a stone; whence coprolite, a 

 fossil dung; M.L. adj . coproliticus of a copro- 

 lite. 



Long, thin rods 0.1 to 0.2 by 6 to 8 (may 

 measure 3 to 40) microns. Straight, S-shaped 

 and curved cells. Motile by means of a sin- 

 gle polar flagellum. 



Peptone soil extract agar: Slight growth. 



Nutrient broth: Little or no growth. 



Thiosulfate agar: Slow development. Pro- 

 duces small, watery colonies raised above 

 the agar surface. Colonies have been noted 

 which were white from precipitated sulfur. 



Thiosulfate broth: Thiosulfate is oxi- 

 dized. Little or no turbidity. No pellicle. 

 No sediment. Change in reaction from pH 

 7.6 to 6.1. 



Sulfur broth: Sulfur is oxidized. No tur- 

 bidity. 



Facultatively autotrophic. 



Aerobic. 



