Thermoacidophilic Algae of North and Central America

Luca, Paolo De; Gambardella, R.; Merola, Aldo

doi:10.1086/337107

Cited by 34 publications

(6 citation statements)

References 13 publications

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“…Nomenclature aside, a predominance of strictly autotrophic spherical thermoacidophilic algae in Nymph Creek is consistent with a traditional microbiological study describing predominantly strictly autotrophic, spherical thermoacidophilic algae in acidic springs in the Norris Geyser basin (15) and with a recent molecular analysis of a low-pH, endolithic algal community in the Norris Geyser basin describing abundant spherical algae with 18S rRNA gene sequences Ͼ99% similar to those of the closest type I relative, the G. maxima/C. caldarium sequence (Fig.…”

Section: Discussionsupporting

confidence: 85%

“…The Norris Geyser basin in Yellowstone National Park contains some of the most extensively studied acidic algal mat communities (10,15). One acidic stream in particular, Nymph Creek, has been the focus of numerous investigations (7, 8, 10, 14, 16, 17, 19, 22, 38-40, 42, 43); however, microbial species in the Nymph Creek algal mat have been characterized using only traditional microbiological methods.…”

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confidence: 99%

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Algal Species and Light Microenvironment in a Low-pH, Geothermal Microbial Mat Community

Ferris

Sheehan

Kühl

et al. 2005

Appl Environ Microbiol

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Unicellular algae are the predominant microbial mat-forming phototrophs in the extreme environments of acidic geothermal springs. The ecology of these algae is not well known because concepts of species composition are inferred from cultivated isolates and microscopic observations, methods known to provide incomplete and inaccurate assessments of species in situ. We used sequence analysis of 18S rRNA genes PCR amplified from mat samples from different seasons and different temperatures along a thermal gradient to identify algae in an often-studied acidic (pH 2.7) geothermal creek in Yellowstone National Park. Fiber-optic microprobes were used to show that light for algal photosynthesis is attenuated to <1% over the 1-mm surface interval of the mat. Three algal sequences were detected, and each was present year-round. A Cyanidioschyzon merolae sequence was predominant at temperatures of >49°C. A Chlorella protothecoides var. acidicola sequence and a Paradoxia multisita-like sequence were predominant at temperatures of <39°C.

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Section: Discussionsupporting

confidence: 85%

mentioning

confidence: 99%

Algal Species and Light Microenvironment in a Low-pH, Geothermal Microbial Mat Community

Ferris

Sheehan

Kühl

et al. 2005

Appl Environ Microbiol

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“…Assuming that there is no nitrous acid in the cell sap, -dc/dZ x I/Ac = 0-24 s"', calculated by the slope of the straight line in Figure 7{b). Knowing that cells of C. caldarium are 3 jurn diameter spheres on average (De Luca, Gambardella & Merola, 1979) and that 1 ml of packed cells contained 4-2 x 10'" cells, the value of/3/F was 2-26 X 10''m"' for the cell suspension used in this experiment. ^(HNOg) was therefore determined to be 1-1 xlO"'*ms"'.…”

Section: Dependence Of Nitrite Uptake On Ph Of the Mediummentioning

confidence: 97%

Uptake and assimilation of nitrite in the acidophilic red alga Cyanidium caldarium Geitler

Fuggi

1993

New Phytologist

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S U M M A R YThe acidophilic red alga, Cyanidium caldarium Geitler, could use nitrite as a nitrogen source for growth, although this compound was very toxic in acidic media. Growth could be sustained when nitrite was added continuously at il rate lower than the maximum rate of nitrite assimilation for the culture. Nitrite assimilation was derepressed in cells growing on nitrate or nitrite, under nitrogen liinitation and by nitrogen starvation. Ammonium-grown cells showed a limited capacity for nitrite reduction in the light, even if nitrite reductase was not detectable in cell extracts. In acidic media nitrite was taken up mainly through HNO^ influx. Nitrite assimilation, in vivo, was restricted by a saturable step under conditions in which nitrite uptake was not limiting. The pH of the cell suspension affected nitrite assimilation by changing the Ki over the pH range tested but not the I-^,,,,^. The K^_ was inversely proportional to the concentration of H* in the medium. The apparent AT, , value for nitrite of nitrite reductase, in vitro, and its expected apparent K^^^ value, in vivo, estimated from the K^ of nitrite assimilation, suggested that the activity of this enzyme may not be the limiting step of nitrite assiinilation.

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“…caldarium is an unusual species restricted to several acid hot springs in North America, including those in the United States, Mexico, and El Salvador (DeLuca et al, 1979). caldarium is an unusual species restricted to several acid hot springs in North America, including those in the United States, Mexico, and El Salvador (DeLuca et al, 1979).…”

Section: B Other Inland Habitatsmentioning

confidence: 99%