SECTION G
1. Organisms will not grow on meat extract or other complex organic media; strict auto- trophs which use carbon dioxide as the sole source of carbon and which obtain their energj^ from the oxidation of carbon monoxide or other inorganic substances 2 Note: The genus Methanomonas has to be considered here. The information in the Manual does not indicate whether the organism is a strict or facultative autotroph. For this reason any polar flagellate terminating at the genus Pseudo- monas should be checked for its ability to grow by autotrophically oxidizing methane. (See also note on Carhoxydomonas.) Not as above 6 2. Organisms oxidize ammonia to nitrite 3 Organisms oxidize nitrite to nitrate 5 Organisms oxidize inorganic sulfur compounds Thiobacillus -p. 83 Organisms oxidize ferrous iron Ferrobacillus p. 227 Organisms oxidize carbon monoxide Carboxydomonas p. 77 Note: It is reasonably certain that Carboxydomonas is also heterotrophic and may be identical with Hydrogenotnonas. 3. Cells encapsulated ; form zoogloeae 4 Cells not encapsulated Nitrosomonas p. 68 4. Zoogloeae encysted Nitrosocystis p. 70 Zoogloeae not encysted Nitrosogloea p. 71 5. Zoogloeae formed Nitrocystis p. 73 Zoogloeae not formed Nitrobacter p. 72 6. Gram-positive 7 Gram-negative; proceed to Section H p. 1015 7. Aerobic 8 Anaerobic 35 8. Endospores formed Bacillus p. 613 Note: Five species of Clostridium (89 to 93) are described as aerotolerant. Their growth under aerobic conditions is very restricted. No endospores produced 9 9. Organisms show distinct branching in young cultures 10 Organisms do not branch 19 Note: No provision appears to be made for organisms which, under optimal growth conditions, produce long unbranched filaments which, like Nocardia, eventually disintegrate into a series of short rods. The Manual descriptions of Nocardia globerula and N. rubropertincta suggest such forms. The author has observed others in rabbit dung media. It would seem better to assign such forms to a new genus in order to retain the branching character in Nocardia. 10. True branching mycelium produced in young cultures 11 Branching very rudimentary, limited to simple branching of isolated rods, no mycelium formed 16 11. Long, branching filaments which show little or no tendency to fragment completely into short bacillary and coccal elements 12 Organisms produce a well-defined mycelium in the early stages of development and then completely fragment into short bacillary elements. When aerial mycelium is produced it also fragments into rods and coccal elements but does not produce dif- ferentiated conidia. Fragmentation of the mycelium may commence within a few hours or may be delayed for several daj-s Nocardia p. 713 Note: (1) Cultures of Actinoplanes, when cultured on certain media, fail to
produce sporangia and resemble Nocardia.
1008
