Page:Bergey's manual of determinative bacteriology.djvu/98

 Broth: Turbid, somewhat slimy; pellicle occasionally produced.

Milk: No coagulation. A yellow pellicle forms. Medium becomes slimy and assumes a dirty flesh color.

Potato: Moist, yellow, glistening.

Indole not produced.

Hydrogen sulfide not produced.

Nitrites not produced from nitrates.

Carbohydrates not utilized.

Aerobic.

Optimum temperature, between 28° and 30° C.

Facultatively autotrophic.

Distinctive characters: Develops autotrophically in inorganic medium under an atmosphere of H2, O2 and CO2. Oxidizes hydrogen to water and uses CO2 as the source of carbon for growth.

Source: Isolated from soil near Vienna.

Habitat: Probably widely distributed in soil.

2. Hydrogenomonas facilis Schatz and Bovell, 1952. (An undescribed Hydrogenomonas, Schatz, Proc. Soc. Amer. Bact., Baltimore Meeting, 1950, 124; Schatz and Bovell, Jour. Bact., 63, 1952, 87.)

fa′ci.lis. L. adj. facilis ready, quick.

Rods 0.3 by 2.0 microns in autotrophic and 0.4 by 2.5 microns in heterotrophic cultures. Occur singly, in pairs and in short chains. Motile by means of one or two polar flagella. Gram-negative.

Gelatin stab: Rapidly liquefied.

Agar colonies: Round, raised, glistening, translucent, non-fluorescent and non-mucoid. No distinctive odor developed.

Autotrophic media: Cultures readily maintained in media of this type.

Autotrophic gas uptake: The same overall reaction is effected as that carried out by certain anaerobically adapted green algae (6H2 + 2O2 + CO2 → CH2O + 5H2O). In an atmosphere of CO2 and H2, no CO2 fixation accompanies the quantitative reduction of nitrate to nitrite by molecular H2; nor is there any change in concentration of bicarbonate or in total gas pressure (Warburg apparatus) when acetone, pyruvate or α-ketoglutarate are added (Schatz, Jour. Gen. Microbiol., 6, 1952, 329).

Broth: Turbid with pellicle.

Milk: Slowly digested with alkalinization.

Potato: Abundant, spreading, non-pigmented growth.

Indole not produced.

Hydrogen sulfide not produced.

Acetylmethylcarbinol not produced.

Nitrites produced from nitrates.

Aerobic, obligate.

Non-hemolytic.

Optimum temperature, 28° C.

Source: Isolated from soil.

Habitat: Presumably widely distributed in soil.

3. Hydrogenomonas flava Niklewski, 1910. (Jahrb. f. wissensch. Botanik, 48, 1910, 113; emend. Kluyver and Manten, Antonie v. Leeuwenhoek, 8, 1942, 71.)

fla′va. L. flavus yellow.

Rods 1.5 microns in length. Motile by means of polar flagella. Gram-negative.

Agar colonies on inorganic medium in presence of H2, O2 and CO2: Small, smooth, yellow, shining, adhering to medium. Develop well below surface of medium, but growth is paler.

Gelatin not liquefied.

Inorganic liquid medium in presence of H2, O2 and CO2: No pellicle formation. Good development when there is from 2 to 8 per cent oxygen in the gas. At higher O2 concentrations good growth occurs only in association with H. vitrea or other bacteria.

Oxidizes hydrogen to water.

Microaerophilic, growing in an atmosphere of low oxygen tension, not exceeding 8 per cent.

Facultatively autotrophic.

Distinctive characters: Found singly on slides whereas the rod-shaped cells of Hydrogenomonas vitrea tend to cling together in masses. Colonies on agar opaque, not transparent.

Source: Isolated from mud, garden soil, pasture land, vegetable mold and peat.

Habitat: Presumably widely distributed in soil.