Anaerobic photosynthetic bacteria

Free-living bacteria are, however, used as the source of the enzyme nitrogenase, responsible for N2 fixation (1,4,26,80), for research purposes because these ate easier to culture. The enzyme is virtually identical to that from the agriculturally important thizobia. These free-living N2-fixets can be simply classified into aerobes, anaerobes, facultative anaerobes, photosynthetic bacteria, and cyanobacteria. 

The anaerobic photosynthetic bacteria can not produce oxygen in an aerobic atmosphere. They would have produced oxygen carrying out the anaerobic oxidation of the reduced sulfur compounds H2S and S, with the formation of S and SOa ", correspondingly ... 

Tabte 1. Carotenogenesis pathways and their distribution within anaerobic photosynthetic bacteria... 

Table 2. Types of reactions seen in the carotenoid biosynthesis within anaerobic photosynthetic bacteria, and cloned genes from photosynthetic bacteria and other bacteria ...

The Heliobacteriaceae are heliobacteria. They are strictly anaerobic photosynthetic bacteria that contain BChl g as a major pigment. Their RC resembles that of PS I of green plants (Madigan and Ormerod,... 

More than ten genera including about 30 species of aerobic photosynthetic bacteria have now been found (Table 9). They are distinguished from typical anaerobic photosynthetic bacteria in that they synthesize BChl only under the aerobic conditions and can not grow without even in the light. In some species, photosynthetic activities have been demonstrated. The low content of BChl, unique composition of carotenoids, and presence of non-... 

Rhodobacter sulfIdophllus was first isolated by Hansen and Veldkamp (1) in 1973 from marine mud flats of the Netherlands as a new species of facultative anaerobic photosynthetic bacteria belonging to the Rhodospirillaceae. This bacterium has unique characteristics regarding the utilization of hydrogen sulfide and a remarkably high sulfide tolerance for a member of the Rhodospirillaceae. However, little research has been done on this bacterium, except for studies on sulfate metabolism (2). 

To extend the vast flexibility of nature regarding PHA production, it was found that these materials are synthesized, not only by Gram-negative bacteria, but also in a number of Gram-positive countCTparts, bacteria, aerobic, anaerobic, photosynthetic bacteria, as well as in some archaebacteria [42,43]. 

The cytochromes plays a major role as electron carriers in the respiratory chain, as well as taking part in photosynthetic reactions in green plants, algae, and anaerobic photosynthetic bacteria A comprehensive survey of their occurrence, properties, structure, and function has been presented by Lemberg and Barrett (1973). ESR continues to play an important role in the identification of mitochondrial cytochromes (Kilpatrick and Erecinska, 1977), and delineating events in bacterial and plant photosynthesis (Prince et a/., 1978). The role played by the cytochromes of higher plants and algae in photosynthetic electron transport has been reviewed recently (Knaf 1978). The present work deals with some recent developments in the properties of those cytochromes where ESR information has accumulated. 

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