User:Gray0696/Aerobic anoxygenic phototrophic bacteria

Lead
Isolation, Enrichment, and Maintenance

Article body
Aerobic phototrophic bacteria are unable to be isolated on selective medium. Instead, these bacteria are indicated by the colony color due to presence of carotenoids. Aerobic phototrophic bacteria can be isolated using medias that are rich in organic compounds using direct inoculation of water samples or sand samples. Inoculated plates are prepared in conditions similar to the natural environments of the collected sample to increase survivability of the bacteria. The presence of Bchl a is what separates this bacteria from other heterotrophic bacteria.

Aerobic phototrophic species can remain viable for at least 2 months when stored at 4oC in liquid or on agar surfaces. They can also be preserved long-term by storing in liquid nitrogen or at temperatures -70oC and below.

Compared to most other bacteria in their natural environment, AAP have a relatively large predation pressure, resulting in high growth rates which balance out the high level of grazing they experience. The removal of predators and this grazing pressure results in a large increase in AAP relative to the other bacteria in the environment. Additionally, phosphorus has been identified as a common limiting factor in AAP growth, which has been shown to sometimes be a stronger limiting factor to AAP growth than predation. Light availability has also been shown to be a factor that stimulates AAP population growth. One effect light has on AAP that has been linked to increased growth is that it has been shown to increase the membrane potential of the bacteria. Increased light exposure has also been shown to extenuate the growth rate increase caused by removal of predators and the amendment of phosphorus levels. A new strain of aerobic anoxygenic phototrophic bacteria, JF-1, were recently isolated from deep-ocean hydrothermal vent waters. These bacteria were found to be pleomorphic which shapes varying from coccoid and ovoid rods, to bean-shaped. The coccoid bacteria were from 0.4 to 0.5 μm in size. The ovoid rods were 0.4-0.5 by 1.0-1.2 μm in size. Thread-like formations of up to five bacterial cells were also observed in these vents. ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC98932/ ) PUT UNDER CELL STRUCTURE

AAP bacteria are motile due to one polar or subpolar flagellum (147, 208, 214–216, 230). Species of these bacteria such as R. denitrificans and S. sibiricus have up to three subpolar flagella.

LH complexes with unusual absorption maxima have been discovered due to the isolation and characterization of new aerobic phototrophic species.