ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 1. Mutants of A. aerogenes have been isolated which are resistant against chlorate under aerobic conditions and which are blocked in aerobic nitrate assimilation. Under anaerobic conditions only two mutants, which do not assimilate nitrate, were resistant against chlorate. The other mutants are sensitive against chlorate and assimilate nitrate. 2. Some mutants do not form nitrate reductase under anaerobic conditions, while others form only small amounts of active enzyme. 3. In the mutants which do not assimilate nitrate under aerobic conditions, an immediate cessation of growth is obtained when cultures, growing anaerobically with nitrate are shifted to aerobic conditions. Under aerobic conditions no nitrate reductase is formed in the mutants. In the mutants one of the intermediates in the aerobic electron transport chain to nitrate is supposed to be missing. 4. In most of the mutants formate metabolism in one way or another is affected. Some of the mutants never oxidize formate nor form hydrogen from formate. In other mutants these properties depend on the growth medium and on the growth temperatures. It has been concluded that formate dehydrogenase and the factor X of the formate hydrogenlyase system are affected. 5. Hydrogenase was present in cell-free extracts of all mutants after anaerobic growth on ammonia. In the mutants, which never form nitrate reductase, hydrogenase was not repressed by addition of nitrate to the anaerobic growth medium, as in wild type A. aerogenes. 6. The particles on which the enzymes concerned are located, are supposed to be changed in different ways, leading to a large variety of properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00408806
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