Rhodospirillales

Rhodospirillales is an order of bacteria within the class Alphaproteobacteria. This order is characterized by its members' ability to perform photosynthesis under anaerobic conditions, a process known as anoxygenic photosynthesis. The Rhodospirillales are further divided into several families, including the Rhodospirillaceae, Acetobacteraceae, and Azospirillaceae.

Characteristics

Members of the Rhodospirillales are typically Gram-negative, rod-shaped, and motile. They are found in a variety of environments, including soil, water, and the gastrointestinal tracts of animals. Many species are capable of nitrogen fixation, a process that converts atmospheric nitrogen into a form that can be used by plants.

Photosynthesis

Unlike most photosynthetic organisms, Rhodospirillales perform anoxygenic photosynthesis, meaning they do not produce oxygen as a byproduct. Instead, they use other molecules, such as hydrogen sulfide or organic matter, as electron donors. This allows them to inhabit environments where oxygen is scarce or absent.

Ecological Role

Rhodospirillales play a crucial role in the nitrogen cycle, as many species are capable of nitrogen fixation. This process is essential for plant growth, as it converts atmospheric nitrogen into a form that plants can use. Some species of Rhodospirillales are also used in bioremediation, a process that uses organisms to clean up environmental pollutants.

Medical Relevance

While Rhodospirillales are not typically pathogenic, some species have been associated with human disease. For example, Acetobacter species have been implicated in infections of the skin and soft tissues, particularly in immunocompromised individuals.

See Also

• Bacteria
• Photosynthesis
• Nitrogen fixation
• Bioremediation