Читать книгу Molecular Mechanisms of Photosynthesis - Robert E. Blankenship - Страница 27

There are seven distinct major groups, or phyla, of bacteria that are capable of photosynthesis (Hohmann‐Marriott and Blankenship, 2012; Thiel et al., 2018). Six of these are anoxygenic, in that they do not produce molecular oxygen as a by‐product of photosynthesis (Blankenship et al., 1995). These anoxygenic phototrophic bacteria include the purple bacteria, the green sulfur bacteria, the filamentous anoxygenic phototrophs (FAP), formerly known as green nonsulfur bacteria, the heliobacteria, the chloroacidobacteria, and the gemmatimonadetes. Each will be introduced briefly below. The single oxygen‐evolving, or oxygenic, group of photosynthetic bacteria is the cyanobacteria (Bryant, 1994). Each of these groups is a relatively coherent collection of organisms with many similar properties in the pigments they contain and the way they carry out photosynthesis. The groups have been established over many years and are based on a number of characteristics, including pigment composition and metabolic capabilities. Fortunately, these groups are also generally similar to those revealed by the rRNA classification method discussed above. Figure 2.2 illustrates schematically the molecular complexes and metabolisms found in each of the phyla of anoxygenic phototrophic prokaryotes (left panel) and oxygenic photosynthetic organisms (right panel)

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Figure 2.2 Photosynthetic machinery and electron transport of photosynthetic organisms, including a description of photosynthetic complexes. Left panel: anoxygenic phototrophs; right panel: oxygenic photosynthetic organisms.

Source: Courtesy of Martin Hohmann‐Marriott.