Publications by authors named "Nathalie Kowalczyk"

Red algae are the oldest identifiable multicellular eukaryotes, with a fossil record dating back more than a billion years. During that time two major rhodophyte lineages, bangiophytes and florideophytes, have evolved varied levels of morphological complexity. These two groups are distinguished, in part, by different patterns of multicellular development, with florideophytes exhibiting a far greater diversity of morphologies.

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Chondrus crispus is a common red macroalga living on the rocky shores of the North Atlantic Ocean. It has a long research history, being a major source of carrageenan, a thickener widely used in the food industry, but also for physiological and ecological studies. To establish it as a model for red algae, its genome has been sequenced, allowing the development of molecular tools such as quantification of gene expression, including RNAseq and RT-qPCR.

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Chondrus crispus is a species of red algae that grows on rocks from the middle intertidal into the subtidal zones of the North Atlantic coasts. As such, it has to cope with strongly variable abiotic conditions. Here we studied the response of the photosynthetic apparatus of this red alga to illumination.

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Article Synopsis
  • Red seaweeds like Chondrus crispus (Irish moss) are important for coastal ecosystems and the economy but have been understudied genetically; researchers have sequenced its 105-Mbp genome, identifying 9,606 genes.
  • The genome has a unique structure with densely packed genes but also regions rich in repetitive DNA, and it reveals characteristics typical of compact genomes, including few introns and limited gene families.
  • The study also highlights important metabolic adaptations in marine red algae, including specialized carbohydrate metabolism, and suggests an evolutionary history of gene loss followed by increased genome size due to transposable elements.
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Ectocarpus siliculosus is a small brown alga that has recently been developed as a genetic model. Its thallus is filamentous, initially organized as a main primary filament composed of elongated cells and round cells, from which branches differentiate. Modeling of its early development suggests the involvement of very local positional information mediated by cell-cell recognition.

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