Page:Bergey's manual of determinative bacteriology.djvu/107

 cultures differ in appearance from Thiobacillus thioparus. Ferrous iron serves as a sufficient energy source with the concomitant 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-oxidizing 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 marcasite.

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, becoming 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, brownish 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; penetrates to bottom of tube.

Thiosulfate agar stab: No appreciable surface growth.

Broth: Slightly turbid. Gelatinous pellicle. Forms long, streamer-like network extending from surface to the bottom. Some sediment.

Thiosulfate broth: Uniform turbidity. No pellicle. Whitish sediment with thin, incomplete 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 alkaline 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 thiosulfate 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.lit′i.cus. Gr. noun coprus dung; Gr. noun lithus a stone; whence coprolite, a fossil dung; M.L. adj. coproliticus of a coprolite.

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 single polar flagellum.

Peptone soil extract agar: Slight growth.

Nutrient broth: Little or no growth.

Thiosulfate agar: Slow development. Produces small, watery colonies raised above the agar surface. Colonies have been noted which were white from precipitated sulfur.

Thiosulfate broth: Thiosulfate is oxidized. Little or no turbidity. No pellicle. No sediment. Change in reaction from pH 7.6 to 6.1.

Sulfur broth: Sulfur is oxidized. No turbidity.

Facultatively autotrophic.

Aerobic.