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| Bird, Clare; Lekieffre, Charlotte; Jauffrais, Thierry; Meibom, Anders; Geslin, Emmanuelle; Filipsson, Helena L.; Maire, Olivier; Russell, Ann D.; Fehrenbacher, Jennifer S.. |
| Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptoplast-containing protists of the phylum foraminifera, possibly via the glutamine synthetase/glutamate synthase (GS/GOGAT) assimilation pathway imported with the kleptoplasts. However, it is not known if the ubiquitous and diverse heterotrophic protists have an innate ability for ammonium assimilation. Using stable isotope incubations (15N-ammonium and 13C-bicarbonate) and combining transmission electron microscopy (TEM) with quantitative nanoscale secondary ion mass spectrometry (NanoSIMS) imaging, we... |
| Tipo: Text |
Palavras-chave: Nitrogen cycle; Heterotrophic protists; Foraminifera; Ammonium assimilation; Heterotrophy; Marine. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00662/77421/79087.pdf |
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| Jauffrais, Thierry; Lekieffre, Charlotte; Schweizer, Magali; Jesus, Bruno; Metzger, Edouard; Geslin, Emmanuelle. |
| The aim of this work is to document the complex nutritional strategy developed by kleptoplastic intertidal foraminifera. We study the mixotrophic ability of a common intertidal foraminifer, E. williamsoni, by (1) investigating the phylogenetic identity of the foraminiferal kleptoplasts, (2) following their oxygenic photosynthetic capacity, and (3) observing the modification in cellular ultrastructural features in response to photoautotrophic conditions. This was achieved by coupling molecular phylogenetic analyses and TEM observations with non-destructive measurements of kleptoplast O2 production over a 15-day experimental study. Results show that the studied E. williamsoni actively selected kleptoplasts mainly from pennate diatoms and had the ability to... |
| Tipo: Text |
Palavras-chave: Foraminifera; Electron microscopy; DNA barcoding; Kleptoplasty; Lipids. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59894/63074.pdf |
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| Jauffrais, Thierry; Lekieffre, Charlotte; Schweizer, Magali; Geslin, Emmanuelle; Metzger, Edouard; Bernhard, Joan M.; Jesus, Bruno; Filipsson, Helena L.; Maire, Olivier; Meibom, Anders. |
| The assimilation of inorganic compounds in foraminiferal metabolism compared to predation or organic matter assimilation is unknown. Here we investigate possible inorganic‐compound assimilation in Nonionellina labradorica, a common kleptoplastidic benthic foraminifer from Arctic and North Atlantic sublittoral regions. The objectives were to identify the source of the foraminiferal kleptoplasts, assess their photosynthetic functionality in light and darkness, and investigate inorganic nitrogen and sulfate assimilation. We used DNA barcoding of a ~830 bp fragment from the SSU rDNA to identify the kleptoplasts, and correlated transmission electron microscopy and nanometer‐scale secondary ion mass spectrometry (TEM‐NanoSIMS) isotopic imaging to study... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57188/59151.pdf |
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