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 



