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Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements

We examined the ability of different freshwater bacterial groups to take up leucine and thymidine in two lakes. Utilization of both substrates by freshwater bacteria was examined at the community level by looking at bulk incorporation rates and at the single-cell level by combining fluorescent in si...

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Autores principales: Pérez, María Teresa, Hörtnagl, Paul, Sommaruga, Ruben
Formato: Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810431/
https://www.ncbi.nlm.nih.gov/pubmed/19725866
http://dx.doi.org/10.1111/j.1462-2920.2009.02043.x
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author Pérez, María Teresa
Hörtnagl, Paul
Sommaruga, Ruben
author_facet Pérez, María Teresa
Hörtnagl, Paul
Sommaruga, Ruben
author_sort Pérez, María Teresa
collection PubMed
description We examined the ability of different freshwater bacterial groups to take up leucine and thymidine in two lakes. Utilization of both substrates by freshwater bacteria was examined at the community level by looking at bulk incorporation rates and at the single-cell level by combining fluorescent in situ hybridization and signal amplification by catalysed reporter deposition with microautoradiography. Our results showed that leucine was taken up by 70–80% of Bacteria-positive cells, whereas only 15–43% of Bacteria-positive cells were able to take up thymidine. When a saturating substrate concentration in combination with a short incubation was used, 80–90% of Betaproteobacteria and 67–79% of Actinobacteria were positive for leucine uptake, whereas thymidine was taken up by < 10% of Betaproteobacteria and by < 1% of the R-BT subgroup that dominated this bacterial group. Bacterial abundance was a good predictor of the relative contribution of bacterial groups to leucine uptake, whereas when thymidine was used Actinobacteria represented the large majority (> 80%) of the cells taking up this substrate. Increasing the substrate concentration to 100 nM did not affect the percentage of R-BT cells taking up leucine (> 90% even at low concentrations), but moderately increased the fraction of thymidine-positive R-BT cells to a maximum of 35% of the hybridized cells. Our results show that even at very high concentrations, thymidine is not taken up by all, otherwise active, bacterial cells.
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spelling pubmed-28104312010-01-26 Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements Pérez, María Teresa Hörtnagl, Paul Sommaruga, Ruben Environ Microbiol Research articles We examined the ability of different freshwater bacterial groups to take up leucine and thymidine in two lakes. Utilization of both substrates by freshwater bacteria was examined at the community level by looking at bulk incorporation rates and at the single-cell level by combining fluorescent in situ hybridization and signal amplification by catalysed reporter deposition with microautoradiography. Our results showed that leucine was taken up by 70–80% of Bacteria-positive cells, whereas only 15–43% of Bacteria-positive cells were able to take up thymidine. When a saturating substrate concentration in combination with a short incubation was used, 80–90% of Betaproteobacteria and 67–79% of Actinobacteria were positive for leucine uptake, whereas thymidine was taken up by < 10% of Betaproteobacteria and by < 1% of the R-BT subgroup that dominated this bacterial group. Bacterial abundance was a good predictor of the relative contribution of bacterial groups to leucine uptake, whereas when thymidine was used Actinobacteria represented the large majority (> 80%) of the cells taking up this substrate. Increasing the substrate concentration to 100 nM did not affect the percentage of R-BT cells taking up leucine (> 90% even at low concentrations), but moderately increased the fraction of thymidine-positive R-BT cells to a maximum of 35% of the hybridized cells. Our results show that even at very high concentrations, thymidine is not taken up by all, otherwise active, bacterial cells. Blackwell Publishing Ltd 2010-01 /pmc/articles/PMC2810431/ /pubmed/19725866 http://dx.doi.org/10.1111/j.1462-2920.2009.02043.x Text en © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
spellingShingle Research articles
Pérez, María Teresa
Hörtnagl, Paul
Sommaruga, Ruben
Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title_full Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title_fullStr Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title_full_unstemmed Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title_short Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
title_sort contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements
topic Research articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810431/
https://www.ncbi.nlm.nih.gov/pubmed/19725866
http://dx.doi.org/10.1111/j.1462-2920.2009.02043.x
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