scholarly journals Artificial cold-adapted microbial mats cultured from Antarctic lake samples. 2. Short-term temperature effects on oxygen turn-over

2001 ◽  
Vol 26 ◽  
pp. 127-138 ◽  
Author(s):  
O Pringault ◽  
E Buffan-Dubau ◽  
R de Wit
Keyword(s):  
Temperature Effects ◽  
Microbial Mats ◽  
Antarctic Lake ◽  
Short Term ◽  
Cold Adapted ◽  
Turn Over

scholarly journals Short-Term Stable Isotope Probing of Proteins Reveals Taxa Incorporating Inorganic Carbon in a Hot Spring Microbial Mat

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Laurey Steinke ◽  
Gordon W. Slysz ◽  
Mary S. Lipton ◽  
Christian Klatt ◽  
James J. Moran ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Inorganic Carbon ◽  
Microbial Mats ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Hot Spring ◽  
Stable Isotope Probing ◽  
Short Term ◽  
Low Light ◽  
Assembly Sequences

ABSTRACT The upper green layer of the chlorophototrophic microbial mats associated with the alkaline siliceous hot springs of Yellowstone National Park consists of oxygenic cyanobacteria (Synechococcus spp.), anoxygenic Roseiflexus spp., and several other anoxygenic chlorophototrophs. Synechococcus spp. are believed to be the main fixers of inorganic carbon (Ci), but some evidence suggests that Roseiflexus spp. also contribute to inorganic carbon fixation during low-light, anoxic morning periods. Contributions of other phototrophic taxa have not been investigated. In order to follow the pathway of Ci incorporation into different taxa, mat samples were incubated with [13C]bicarbonate for 3 h during the early-morning, low-light anoxic period. Extracted proteins were treated with trypsin and analyzed by mass spectrometry, leading to peptide identifications and peptide isotopic profile signatures containing evidence of 13C label incorporation. A total of 25,483 peptides, corresponding to 7,221 proteins, were identified from spectral features and associated with mat taxa by comparison to metagenomic assembly sequences. A total of 1,417 peptides, derived from 720 proteins, were detectably labeled with 13C. Most 13C-labeled peptides were derived from proteins of Synechococcus spp. and Roseiflexus spp. Chaperones and proteins of carbohydrate metabolism were most abundantly labeled. Proteins involved in photosynthesis, Ci fixation, and N2 fixation were also labeled in Synechococcus spp. Importantly, most proteins of the 3-hydroxypropionate bi-cycle for Ci fixation in Roseiflexus spp. were labeled, establishing that members of this taxocene contribute to Ci fixation. Other taxa showed much lower [13C]bicarbonate incorporation. IMPORTANCE Yellowstone hot spring mats have been studied as natural models for understanding microbial community ecology and as modern analogs of stromatolites, the earliest community fossils on Earth. Stable-isotope probing of proteins (Pro-SIP) permitted short-term interrogation of the taxa that are involved in the important process of light-driven Ci fixation in this highly active community and will be useful in linking other metabolic processes to mat taxa. Here, evidence is presented that Roseiflexus spp., which use the 3-hydroxypropionate bi-cycle, are active in Ci fixation. Because this pathway imparts a lower degree of selection of isotopically heavy Ci than does the Calvin-Benson-Bassham cycle, the results suggest a mechanism to explain why the natural abundance of 13C in mat biomass is greater than expected if only the latter pathway were involved. Understanding how mat community members influence the 13C/12C ratios of mat biomass will help geochemists interpret the 13C/12C ratios of organic carbon in the fossil record.

The Thermoluminescence 'Afterglow' Band as a Sensitive Indicator of Abiotic Stresses in Plants

1999 ◽  
Vol 54 (9-10) ◽  
pp. 629-633 ◽  
Author(s):  
Tibor Janda ◽  
Gabriella Szalai ◽  
Catherine Giauffret ◽  
Emil Páldi ◽  
Jean-Marc Ducruet
Keyword(s):  
Abiotic Stresses ◽  
Red Light ◽  
Freezing Temperature ◽  
Short Term ◽  
Sudden Drop ◽  
Stress Indicator ◽  
Single Turn ◽  
Cold Sensitive ◽  
Maize Plants ◽  
Turn Over

Single turn-over xenon flashes induce a thermoluminescence (TL) B-band centred near 35 °C. The far-red illumination of leaves at non-freezing temperatures induces a band peaking at around 45 °C (afterglow or AG-band), together with a downshifted B-band peaking between 15 °C and 28 °C. In control, unfrozen wheat plants, the Tmax of the B-band induced after 30 s far-red light at 0 °C was approx. 15-18 °C. In maize plants grown under the same conditions, this far-red-induced downshift was not so strong, since the B-band peaked at 28 - 30 °C. Both a decline in the AG-band and a reversal of the downshift of the B-band were observed after short-term freezing in several plant species. There was usually a sudden drop in the AG-band below a critical freezing temperature. However, while in wheat plants a weak TL emission could be seen between 40-50 °C in frozen samples, in cold-sensitive maize plants this was completely suppressed and only the B-band could be detected. In cold-hardened wheat plants the temperature at which the AG-band was suppressed was lower than in non-hardened plants. Drought and short-term heat stress also affect the AG-band. As the AG-band was found to be more sensitive to several types of stresses than the B-band, it can be used as a sensitive stress indicator. However, the behaviour of the AG-band depends on several factors (for example the age of the leaf, etc.), which must be controlled if different species or varieties are to be compared

Sea-level variation and the zonation of microbialites in Hamelin Pool, Shark Bay, Western Australia

2012 ◽  
Vol 63 (11) ◽  
pp. 994 ◽  
Author(s):  
Robert V. Burne ◽  
Ken Johnson
Keyword(s):  
Microbial Communities ◽  
Sea Level ◽  
Seasonal Cycle ◽  
Microbial Mats ◽  
Level Variation ◽  
Short Term ◽  
Shark Bay ◽  
Astronomical Tide ◽  
Sea Level Variation ◽  
Modern Methods

The application of modern methods of time-series analysis to a record of sea-level variation at Flint Cliff, Hamelin Pool, between October 1983 and April 1985, shows that astronomical tides account for only one of the following five key components of the record: a seasonal oceanic cycle; a short-term irregular cycle; the complex astronomical tidal system in the Pool; isolated major events; and less marked variations probably reflecting wind stress, still able to defeat the astronomical tide in the short-term. We have compared the inundation record with precisely surveyed elevation ranges of various microbial communities. The dominance of a seasonal cycle is the fundamental determinant of variation in the duration of immersion and exposure determining the littoral zonation of microbial mats in Hamelin Pool. The astronomical tide is not the major cause of this variation. The microbial communities fall into three zones. In Zone 3, the microbialite-forming colloform mat is virtually never exposed. In Zone 2, smooth, reticulate and mamillate mats colonise the lower littoral environment. Here, many of the exposed microbialites have been stranded by the falling sea level, and are colonised by intermittently submerged microbial communities that modify the stranded lithified microbialites. Zone 1 is inundated only under exceptional circumstances and microbial communities are ephemeral.

Short-term temperature effects on the anaerobic metabolism of glycogen accumulating organisms

2007 ◽  
Vol 97 (3) ◽  
pp. 483-495 ◽  
Author(s):  
Carlos M. Lopez-Vazquez ◽  
Young-Il Song ◽  
Christine M. Hooijmans ◽  
Damir Brdjanovic ◽  
Moustafa S. Moussa ◽  
...  
Keyword(s):  
Temperature Effects ◽  
Anaerobic Metabolism ◽  
Short Term
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