Abundance and salt tolerance of obligately aerobic, phototrophic bacteria in a marine microbial mat

ABSTRACT Production of a photosynthetic apparatus in Roseateles depolymerans 61A, a recently discovered freshwater β-Proteobacterium showing characteristics of aerobic phototrophic bacteria, was observed when the cells were subjected to a sudden decrease in carbon sources (e.g., when cells grown with 0.1 to 0.4% Casamino Acids were diluted or transferred into medium containing ≤0.04% Casamino Acids). Accumulation of bacteriochlorophyll (BChl) a was observed in the presence of oxygen and was enhanced under semiaerobic conditions (2% oxygen) but was reduced in the presence of light. Similarly to what has been reported regarding some aerobic phototrophic bacteria belonging to the α subclass of the Proteobacteria, viability of the cells in the carbon source-free medium was prolonged under aerobic-light (10 W m−2) conditions, possibly due to photosynthetic energy conversion, but was not prolonged under aerobic-dark conditions. The puf operon, which encodes most of the apoproteins of light-harvesting and reaction center complexes, was sequenced, and the effect of changes in Casamino Acids concentrations, oxygen, and light on its expression was estimated by the accumulation of its mRNA. The expression of the puf operon was induced by the decrease in carbon sources, similarly to what was observed for the accumulation of BChl a under aerobic and semiaerobic conditions (≥0.2% O2), and was reduced in the presence of light. Transcription of the R. depolymerans puf operon is considered to be controlled by changes in carbon nutrients in addition to oxygen tension and light intensity.

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Competition between anoxygenic phototrophic bacteria and colorless sulfur bacteria in a microbial mat

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.1992.tb05761.x ◽

1992 ◽

Vol 101 (1) ◽

pp. 51-58 ◽

Cited By ~ 2

Author(s):

Pieter T. Visscher ◽

Frank P. Ende ◽

Bartholomeus E.M. Schaub ◽

Hans Gemerden

Keyword(s):

Phototrophic Bacteria ◽

Microbial Mat ◽

Anoxygenic Phototrophic Bacteria ◽

Sulfur Bacteria ◽

Colorless Sulfur Bacteria

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Aerobic Phototrophic Bacteria: New Evidence for the Diversity, Ecological Importance and Applied Potential of this Previously Overlooked Group

Photosynthesis Research ◽

10.1023/b:pres.0000035036.49977.bc ◽

2004 ◽

Vol 81 (2) ◽

pp. 113-128 ◽

Cited By ~ 53

Author(s):

Christopher Rathgeber ◽

J. Thomas Beatty ◽

Vladimir Yurkov

Keyword(s):

Phototrophic Bacteria ◽

Applied Potential ◽

Ecological Importance ◽

New Evidence ◽

Aerobic Phototrophic Bacteria

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Aerobic Anoxygenic Phototrophic Bacteria

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.62.3.695-724.1998 ◽

1998 ◽

Vol 62 (3) ◽

pp. 695-724 ◽

Cited By ~ 303

Author(s):

Vladimir V. Yurkov ◽

J. Thomas Beatty

Keyword(s):

Phototrophic Bacteria ◽

Anoxygenic Phototrophic Bacteria ◽

Photosynthetic Unit ◽

Light Harvesting Complexes ◽

Aerobic Anoxygenic Phototrophic Bacteria ◽

Low Levels ◽

Compare And Contrast ◽

Bacterial Groups ◽

Distinguishing Features ◽

Aerobic Phototrophic Bacteria

SUMMARY The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes.

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