Purple sulfur bacteria Purple sulfur bacteria The purple sulfur bacteria (PSB) are part of a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in stratified water environments including hot springs, stagnant water bodies, as well as microbial mats in intertidal zones. Unlike plants, algae, and cyanobacteria, purple sulfur bacteria do not use water as their reducing agent, and therefore do not produce oxygen. Instead, they can use sulfur in the form of sulfide, or thiosulfate (as well, some species can use H, Fe, or NO) as the electron donor in
Fungal-bacterial endosymbiosis associations. What is known on these associations impacts our understanding of the ecological interactions of plants, fungi and bacteria. The classification of bacterial endosymbionts and their fungal partners occur across a diverse set of phyla. Ca. G. sporarum and Burkholderia sp. have been identified to be β-proteobacteria, a gram-negative class of bacteria, and N. punctiforme is a cyanobacteria . These phyla are not closely related showing that the capability of endosymbiosis with fungi is widely spread. A similar pattern is seen with the fungal partners with examples occurring across broad phyla/divisions such as Glomeromycota, Zygomycota, Ascomycota and Basidiomycota. The common