Incorporation of 3H-Thymidine by Different Prokaryotic Groups in Relation to Temperature and Nutrients in a Lacustrine Ecosystem

Delphine Boucher; Mathilde Richardot; Aurélie Thénot; Didier Debroas

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Incorporation of 3H-Thymidine by Different Prokaryotic Groups in Relation to Temperature and Nutrients in a Lacustrine Ecosystem

Delphine Boucher ^[1] ; Mathilde Richardot ^[1] ; Aurélie Thénot ^[1] ; Didier Debroas ^[1]
1. [1] Blaise Pascal University
  
  Blaise Pascal University
  
  Arrondissement de Clermont-Ferrand, Francia
Localización: Microbial ecology, ISSN-e 1432-184X, ISSN 0095-3628, Vol. 52, Nº. 3, 2006, págs. 399-407
Idioma: inglés
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Resumen
- The incorporation of [3H-methyl] thymidine (3H-TdR) by Eubacteria, bacterial groups (α- and β-Proteobacteria, Cytophaga–Flavobacter), and Archaea was measured according to temperature (7 and 17°C) and nutrient levels (nitrogen, phosphorus, and carbon) in a lacustrine system (Sep, France). Short-term incubation was performed using a combination of microautoradiography and fluorescent in situ hybridization. Irrespective of the temperatures and nutrients studied, all the major phylogenetic bacterial groups assimilated 3H-TdR, and in most of the treatments studied, the proportion of β-Proteobacteria taking up 3H-TdR was higher than those in the other bacterial groups. The proportion of Bacteria and different bacterial groups studied incorporating 3H-TdR were significantly increased, approximately 1.5-fold, by temperature except for α-Proteobacteria (7.6-fold). The nutrient effect was not the same for the different bacterial groups according to the temperatures studied. The proportions of α-Proteobacteria (at both temperatures) and Cytophaga–Flavobacter (at 7°C) taking up 3H-TdR were significantly decreased and increased by adding N and P, respectively. Also, adding N, P, and C increased and decreased the percentage of β-Proteobacteria incorporating 3H-TdR at 7 and 17°C, respectively. The archaeal community showed a similar proportion of active cells (i.e., 3H-TdR) to the bacterial community, and uptake of 3H-TdR by Archaea was significantly increased (P < 0.05) by both temperature and nutrients. Thus, the assimilation of 3H-TdR by bacterial groups and Archaea in lacustrine system is significantly controlled by both temperature and nutrients.