Rhodopseudomonas palustris
Rhodopseudomonas palustris is a rod-shaped, Gram-negative purple nonsulfur bacterium, notable for its ability to switch between four different modes of metabolism. R. palustris is found extensively in nature, and has been isolated from swine waste lagoons, earthworm droppings, marine coastal sediments, and pond water. Although purple nonsulfur bacteria are normally photoheterotrophic, R. palustris can flexibly switch among any of the four modes of metabolism that support life: photoautotrophic, photoheterotrophic, chemoautotrophic, or chemoheterotrophic. Etymology R. palustris is usually found as a wad of slimy masses, and cultures appear from pale brown to peach-colored. Etymologically, rhodum is a Greek noun meaning rose, pseudes is the Greek adjective for false, and monas refers to a unit in Greek. Therefore, Rhodopseudomonas, which implies a unit of false rose, describes the appearance of the bacteria. Palustris is Latin for marshy, and indicates the common habitat of the bacterium. Modes of metabolism R. palustris can grow with or without oxygen, or it can use light or inorganic or organic compounds for energy. It can also acquire carbon from either carbon dioxide fixation or green plant-derived compounds. Finally, R. palustris is also capable of fixing nitrogen for growth. This metabolic versatility has raised interest in the research