Adaptation of the 3H-leucine incorporation technique to measure heterotrophic activity associated with biofilm on the blades of the seaweed Sargassum spp
| Autor: | Jean Remy Davée Guimarães, Leonardo T. Salgado, Marcio Rodrigues Miranda, Sérgio A. Coelho-Souza, Ricardo Coutinho |
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| Rok vydání: | 2012 |
| Předmět: |
Detritus
Ecology Bacteria Light Microorganism fungi Sargassum Biofilm Microbial metabolism Soil Science Heterotrophic Processes Biology biology.organism_classification Seaweed Extracellular polymeric substance Leucine Biofilms Botany Epiphytic bacteria Microscopy Electron Scanning Water Microbiology Ecology Evolution Behavior and Systematics |
| Zdroj: | Microbial ecology. 65(2) |
| ISSN: | 1432-184X |
| Popis: | The ecological interaction between microorganisms and seaweeds depends on the production of secondary compounds that can influence microbial diversity in the water column and the composition of reef environments. We adapted the (3)H-leucine incorporation technique to measure bacterial activity in biofilms associated with the blades of the macroalgae Sargassum spp. We evaluated (1) if the epiphytic bacteria on the blades were more active in detritus or in the biofilm, (2) substrate saturation and linearity of (3)H-leucine incorporation, (3) the influence of specific metabolic inhibitors during (3)H-leucine incorporation under the presence or absence of natural and artificial light, and (4) the efficiency of radiolabeled protein extraction. Scanning electron microscopy showed heterogeneous distribution of bacteria, diatoms, and polymeric extracellular secretions. Active bacteria were present in both biofilm and detritus on the blades. The highest (3)H-leucine incorporation was obtained when incubating blades not colonized by macroepibionts. Incubations done under field conditions reported higher (3)H-leucine incorporation than in the laboratory. Light quality and sampling manipulation seemed to be the main factors behind this difference. The use of specific metabolic inhibitors confirmed that bacteria are the main group incorporating (3)H-leucine but their association with primary production suggested a symbiotic relationship between bacteria, diatoms, and the seaweed. |
| Databáze: | OpenAIRE |
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