ag′il.is. L. adj. agilis agile, quick.
Rods, 0.5 by 0.8 to 0.9 micron, occurring singly, sometimes in pairs or larger aggregates. Rapidly motile with a long, thin, polar flagellum often 7 to 10 times as long as the rod. (Non-motile culture obtained by Kingma Boltjes, Arch. f. Mikrobiol., 6, 1935, 79.) Gram-negative.
No growth in nutrient broth, nutrient agar, nutrient or plain gelatin, litmus or plain milk, glucose or plain yeast water, or on potato.
Nitrite agar: After two weeks, produces semi-spherical, minute, nearly transparent colonies. Oxidation usually complete in 10 to 14 days.
Inorganic liquid medium containing nitrite: Produces uniformly dispersed growth.
Optimum pH, between 7.6 and 8.6. Limits of growth, 6.6 to 10.0.
Temperature relations: Optimum for growth, between 25° and 30° C. Optimum for oxidation, 28° C. No oxidation at 37° C. Thermal death point, 60° C. for five minutes.
Strictly autotrophic.
Aerobic.
Source: Isolated from greenhouse soils and from sewage effluents in Madison, Wisconsin.
Habitat: Presumably widely distributed in soil.
Genus VII. Nitrocystis H. Winogradsky, 1935.
(Trans. Third Intern. Cong. Soil Sci., Oxford, 1, 1935, 139.)
Ni.tro.cyst′is. Gr. noun nitrum nitre, M.L. nitrate; Gr. noun cystis bladder, cyst; M.L. fem. n. Nitrocystis nitrate cyst.
Cells ellipsoidal or rod-shaped. Embedded in slime and united into compact zoogloeal aggregates. Oxidize nitrites to nitrates.
It has been suggested that these organisms were really myxobacters. See note under Nitrosocystis for references.
The type species is Nitrocystis sarcinoides H. Winogradsky.
1. Nitrocystis sarcinoides H. Winogradsky, 1937. (Nitrocystis B. A., H. Winogradsky, Compt. rend. Acad. Sci., Paris, 200, 1935, 1888; also see Ann. Inst. Past., 58, 1937, 336.)
sar.cin.o.i′des. L. sarcina a packet; Gr. idus form, shape; M.L. adj. sarcinoides resembling Sarcina, a genus of bacteria.
Small rods 0.5 by 1.0 micron. Cells ellipsoidal or wedge-shaped and grouped in sarcina-like packets.
Colonies on silica gel: On the surface of gel coated with kaolin the colonies appear as small, raised, amber warts. The colonies grow up to 5 mm in diameter. The colonies are viscous and sticky when young, and they become brown with age, shrink, and look like scales and become hard like grains of sand. Each colony is enveloped in several layers of a thick slime which holds the cells together so that the entire colony can be removed with a transfer needle.
Aerobic.
Source: Activated sludge.
Habitat: Unknown.
2. Nitrocystis micropunctata (H. Winogradsky, 1935) H. Winogradsky, 1937. (Nitrocystis "III", H. Winogradsky, Trans. Third Intern. Cong. Soil Sci., Oxford, 1, 1935, 139; Nitrogloea micropunctata H. Winogradsky, Compt. rend. Acad. Sci., Paris, 200, 1935, 1888; H. Winogradsky, Ann. Inst. Past., 58, 1937, 326.)
mi.cro.punc.ta′ta. Gr. micrus small; L. punctatus spotted; M.L. adj. micropunctatus full of small spots.
Cells are ellipsoidal rods, about 0.5 micron in diameter, which stain poorly except at the ends. Encased in a viscous slime.
Colonies on silica gel: Like those of N. sarcinoides except that they are clearer and have a more plastic consistency. The cells are not held together by the slime in the colony as with N. sarcinoides. The capsule is more readily differentiated in old colonies.
Aerobic.
Source: Activated sludge.
Habitat: Unknown.
