Examinando por Autor "Van Steenkiste, Niels W. L."

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A new case of kleptoplasty in animals: marine flatworms steal functional plastids from diatoms
(American Association for the Advancement of Science, 2019-07) Van Steenkiste, Niels W. L.; Stephenson, India; Herranz, Maria; Filip, Husnik; Keeling, P. J.; Leander, Brian S.
To date, sea slugs have been considered the only animals known to sequester functional algal plastids into their own cells, via a process called “kleptoplasty.” We report here, however, that endosymbionts in the marine flatworms Baicalellia solaris and Pogaina paranygulgus are isolated plastids stolen from diatoms. Ultrastructural data show that kleptoplasts are located within flatworm cells, while algal nuclei and other organelles are absent. Transcriptomic analysis and rbcL amplicons confirm the absence of algal nuclear mRNA and reveal that the plastids originate from different species of diatoms. Laboratory experiments demonstrated photosynthetic activity and short-term retention of kleptoplasts in starved worms. This lineage of flatworms represents the first known case of functional kleptoplasty involving diatoms and only the second known case of kleptoplasty across the entire tree of animals.
Microbiomes of microscopic marine invertebrates do not reveal signatures of phylosymbiosis
(Nature Research, 2022-05) Boscaro, Vittorio; Holt, Corey C.; Van Steenkiste, Niels W. L.; Herranz, Maria; Irwin, Nick A. T.; Álvarez-Campos, Patricia; Grzelak, Kasia; Holovachov, Oleksander; Kerbl, Alexandra; Mathur, Varsha; Okamoto, Noriko; Piercey, Rebecca S.; Worsaae, Katrine; Leander, Brian S.; Keeling, P. J.
Animals and microorganisms often establish close ecological relationships. However, much of our knowledge about animal microbiomes comes from two deeply studied groups: vertebrates and arthropods. To understand interactions on a broader scale of diversity, we characterized the bacterial microbiomes of close to 1,000 microscopic marine invertebrates from 21 phyla, spanning most of the remaining tree of metazoans. Samples were collected from five temperate and tropical locations covering three marine habitats (sediment, water column and intertidal macroalgae) and bacterial microbiomes were characterized using 16S ribosomal RNA gene sequencing. Our data show that, despite their size, these animals harbour bacterial communities that differ from those in the surrounding environment. Distantly related but coexisting invertebrates tend to share many of the same bacteria, suggesting that guilds of microorganisms preferentially associated with animals, but not tied to any specific host lineage, are the main drivers of the ecological relationship. Host identity is a minor factor shaping these microbiomes, which do not show the same correlation with host phylogeny, or ‘phylosymbiosis’, observed in many large animals. Hence, the current debate on the varying strength of phylosymbiosis within selected lineages should be reframed to account for the possibility that such a pattern might be the exception rather than the rule.