Rhodoferax antarcticus sp. nov., a moderately psychrophilic purple nonsulfur bacterium isolated from an Antarctic microbial mat

Madigan, Michael T.; Jung, Deborah O.; Woese, Carl R.; Achenbach, Laurie A.

doi:10.1007/s002030000140

Cited by 117 publications

(100 citation statements)

References 34 publications

(62 reference statements)

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“…A similar dominance by Com1212 relatives was observed in clone libraries from soils collected at the terminus of a Peruvian high-altitude glacier (44) and a collection of isolates from subglacial samples of two New Zealand glaciers (14). 16S rRNA gene sequences or cultures from this cluster have been obtained from other low-temperature environments, including glacial ice cores (52), Antarctic marine (27) and lake (40) waters, and other uncultured organisms from cold or frozen environments (18,20). Thus, the "Com1212" cluster appears to be ubiquitous in cold and frozen environments and may be predominant in many subglacial environments.…”

Section: Resultsmentioning

confidence: 56%

Comparison of Microbial Community Compositions of Two Subglacial Environments Reveals a Possible Role for Microbes in Chemical Weathering Processes

Skidmore

Anderson

Sharp

et al. 2005

Appl Environ Microbiol

245

206

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Viable microbes have been detected beneath several geographically distant glaciers underlain by different lithologies, but comparisons of their microbial communities have not previously been made. This study compared the microbial community compositions of samples from two glaciers overlying differing bedrock. Bulk meltwater chemistry indicates that sulfide oxidation and carbonate dissolution account for 90% of the solute flux from Bench Glacier, Alaska, whereas gypsum/anhydrite and carbonate dissolution accounts for the majority of the flux from John Evans Glacier, Ellesmere Island, Nunavut, Canada. The microbial communities were examined using two techniques: clone libraries and dot blot hybridization of 16S rRNA genes. Two hundred twenty-seven clones containing amplified 16S rRNA genes were prepared from subglacial samples, and the gene sequences were analyzed phylogenetically. Although some phylogenetic groups, including the Betaproteobacteria, were abundant in clone libraries from both glaciers, other well-represented groups were found at only one glacier. Group-specific oligonucleotide probes were developed for two phylogenetic clusters that were of particular interest because of their abundance or inferred biochemical capabilities. These probes were used in quantitative dot blot hybridization assays with a range of samples from the two glaciers. In addition to shared phyla at both glaciers, each glacier also harbored a subglacial microbial population that correlated with the observed aqueous geochemistry. These results are consistent with the hypothesis that microbial activity is an important contributor to the solute flux from glaciers.

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Section: Resultsmentioning

confidence: 56%

Comparison of Microbial Community Compositions of Two Subglacial Environments Reveals a Possible Role for Microbes in Chemical Weathering Processes

Skidmore

Anderson

Sharp

et al. 2005

Appl Environ Microbiol

245

206

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“…Surprisingly, no pufM sequences obtained from Lake Fryxell showed similarity to the pufM genes of purple sulfur bacteria. Moreover, only one clone group (group E) contained a pufM sequence exhibiting more than 90% sequence similarity to the pufM gene of a cultured purple nonsulfur bacterium, Rhodoferax antarcticus (14), suggesting that novel purple bacteria inhabit Lake Fryxell.…”

Section: Resultsmentioning

confidence: 99%

“…Enrichment cultures were established in three different media: (i) medium AB, a malate-mineral salts medium for purple nonsulfur bacteria (14); (ii) medium Pf-7, a mineral salts-sulfide medium suitable for growth of phototrophic purple or green bacteria (30); and (iii) a 1:2 mixture of medium AB and medium Pf-7. The final pH of all media was 7.2.…”

Section: Methodsmentioning

confidence: 99%

Remarkable Diversity of Phototrophic Purple Bacteria in a Permanently Frozen Antarctic Lake

Karr

Sattley

Jung

et al. 2003

Appl Environ Microbiol

Self Cite

133

137

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Although anoxygenic photosynthesis is thought to play an important role in the primary productivity of permanently frozen lakes in the Antarctic dry valleys, the bacterial communities responsible for this metabolism remain uncharacterized. Here we report the composition and activity of phototrophic purple bacteria in Lake Fryxell, Antarctica, as determined by analysis of a photosynthesis-specific gene, pufM. The results revealed an extensive diversity and highly stratified distribution of purple nonsulfur bacteria in Lake Fryxell and showed which phylotypes produced pufM transcripts in situ. Enrichment cultures for purple bacteria yielded two morphotypes, each with a pufM signature identical to signatures detected by environmental screening. The isolates also contained gas vesicles, buoyancy structures previously unknown in purple nonsulfur bacteria, that may be necessary for these organisms to position themselves at specific depths within the nearly freezing water column.Lake Fryxell is a meromictic lake located 18 m above sea level at the entrance of Taylor Valley adjacent to McMurdo Sound, Antarctica (17). The lake is a closed basin with a maximum depth of 19 m (28). Lake Fryxell has undergone several dry-down periods in the past, resulting in slightly saline bottom waters overlaid with more dilute water introduced from glacial meltwater streams (12,20). This process has resulted in a gradient of solutes in the water column that is further stabilized by a perennial ice cover that is 3 to 5 m thick (25,28). The mixolimnion of the water column is supersaturated with oxygen, while the monimolimnion is anoxic due to limited gas exchange imposed by the perennial ice cover. The latter also serves as a barrier to light penetration, allowing only a small amount of light to reach the water column; for example, in Lake Fryxell, photosynthetically active radiation (PAR) is reduced by more than 90% from a depth of 4 to 9 m and by another 90% from 9 to 11 m (2, 23).There have been extensive studies of the geochemistry of Lake Fryxell, but to date only a few studies of the microbial communities that inhabit the lake have been reported (16,24). These studies focused on ammonia-oxidizing bacteria (members of the ␥ and ␤ subdivisions of the Proteobacteria) within the water column and the contributions of cyanobacteria inhabiting the lake's ice cover to primary production in the dry valley ecosystem (6, 29). Studies of the bacterial diversity of microbial mat samples collected from moats that surround the lake during the austral summer season showed a large degree of microbial diversity, including both gram-positive and gramnegative bacteria, as well as Archaea (4).The presence of a year-round ice layer on Lake Fryxell prevents active mixing and maintains an extensive anoxic zone containing sulfide, which is suitable for development of anoxygenic phototrophic purple bacteria (21, 23). These organisms, although phototrophic, do not evolve oxygen and are members of the ␣, ␤, and ␥ subdivisions of the Proteobacteria (10, 11). The...

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“…After growth under anaerobic photoheterotrophic conditions, cell suspensions were red and the absorption spectra of living cells suspension showed maxima at 370, 570, 800, 827 and 852 as shown in Fig.1. The two main peaks at 800 and 850 nm, which are closely related to bacteriochlorophyll a and b (characteristics of photobacteria pigment) as well as carotenoid, are characteristics of PNSB (Madigan et al, 2000). By GC-FAME (Gas chromatography of fatty acid methyl ester) analysis the PNSB isolate was identified as being closely related to Rhodobacter sphaeroides strains with similarity indices of 0.85 ± 0.05.…”

Section: Identification Of the Bacteriummentioning

confidence: 98%

Potentials of phototrophic bacteria in treating pharmaceutical wastewater

Madukasi

Dai

et al. 2009

Int. J. Environ. Sci. Technol.

116

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AB STRACT: A suspended growth photobioreactor was utilized to treat pharmaceutical wastewater by a wild strain purple non-sulfur photosynthetic bacterium isolated from the soil. The strain was named Z08 and identified as Rhodobacter-sphaeroides by 16SrDN. The photobioreactor was illuminated externally with two (40 W) fluorescent compact light sources on both sides. Its operation pH and temperature were between 6.8 -7.0 and 20 -30 ºC, respectively. Optimum growth of the isolate was obtained after enrichment of the pharmaceutical wastewater with 0.5 % ammonium sulfate and 0.1 % yeast extract under microaerobic optimum light (6000 lx) condition at 5d retention. Using these optimum conditions, the maximum dry cell weight and chemical oxygen demand percentage removal were 880 mg/L and 80 %. Chemical analysis of the culture after treatment of the enriched and non-enriched wastewater showed the crude protein content of the biomass to be 54.6 % and 38.0 %, respectively. This study proved that photosynthetic bacteria could transform complex wastewater that contains recalcitrant organic compounds with a resultant recovery of useful products.

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Rhodoferax antarcticus sp. nov., a moderately psychrophilic purple nonsulfur bacterium isolated from an Antarctic microbial mat

Cited by 117 publications

References 34 publications

Comparison of Microbial Community Compositions of Two Subglacial Environments Reveals a Possible Role for Microbes in Chemical Weathering Processes

Comparison of Microbial Community Compositions of Two Subglacial Environments Reveals a Possible Role for Microbes in Chemical Weathering Processes

Remarkable Diversity of Phototrophic Purple Bacteria in a Permanently Frozen Antarctic Lake

Potentials of phototrophic bacteria in treating pharmaceutical wastewater

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