Extremely 'vanadiphilic' multiply metal-resistant and halophilic aerobic anoxygenic phototrophs, strains EG13 and EG8, from hypersaline springs in Canada.

Two pinkish peach-colored strains of obligately aerobic phototrophic bacteria, EG13 and EG8, were isolated from a saline spring effluent stream in west central Manitoba, Canada. The strains possessed bacteriochlorophyll a incorporated into a typical purple bacterial light-harvesting complex 1 (870 nm) and reaction center (801 nm). Analysis of 16S rRNA gene sequences indicated 100% identity among the isolates and 99% similarity to Roseovarius tolerans EL-172(T).

Chromocurvus halotolerans gen. nov., sp. nov., a gammaproteobacterial obligately aerobic anoxygenic phototroph, isolated from a Canadian hypersaline spring.

A strain EG19(T) of aerobic bacteria able to form pleomorphic cells was isolated from a brine spring runoff stream in the west central region of the province of Manitoba, Canada. The pale pinkish purple strain contained bacteriochlorophyll a incorporated into light-harvesting I and reaction center complexes. Its inability to grow under anaerobic illuminated conditions prompted designation as a member of the functional group known as aerobic anoxygenic phototrophic bacteria.

An alphaproteobacterium capable of both aerobic and anaerobic anoxygenic photosynthesis but incapable of photoautotrophy: Charonomicrobium ambiphototrophicum, gen. nov., sp. nov.

A facultatively aerobic deep brown coccoid to ovoid bacterium, strain EG17(T), was isolated from a saline effluent stream in the NaCl-dominated brine spring system known as East German Creek in the province of Manitoba, Canada. The strain produced BChl a incorporated into a functional reaction center and two light-harvesting complexes with absorption peaks at 802, 850, and 879 nm. EG17(T) is the first reported anoxygenic phototroph capable of photoheterotrophic growth under both oxic and anoxic conditions.

A new environment for aerobic anoxygenic phototrophic bacteria: biological soil crusts.

Phototrophic microorganisms are critical to the carbon cycling and productivity of biological soil crusts, which enhance water content, nutrient relations and mechanical stability of arid soils. Only oxygen-producing phototrophs, including cyanobacteria and algae, are known from soil crusts, but Earth's second major branch of photosynthetic organisms, the evolutionarily earlier anoxygenic phototrophs, is unreported. We announce the discovery of aerobic anoxygenic phototrophs in three Canadian soil crust communities.

A new extreme environment for aerobic anoxygenic phototrophs: biological soil crusts.

Biological soil crusts improve the health of arid or semiarid soils by enhancing water content, nutrient relations and mechanical stability, facilitated largely by phototrophic microorganisms. Until recently, only oxygenic phototrophs were known from soil crusts. A recent study has demonstrated the presence of aerobic representatives of Earth's second major photosynthetic clade, the evolutionarily basal anoxygenic phototrophs.