A5071937254- Microbial Community Ecology and Physiology
- Protist diversity and phylogeny
- Environmental DNA in Biodiversity Studies
- Genomics and Phylogenetic Studies
- Marine Biology and Ecology Research
- Marine and coastal ecosystems
- Bacteriophages and microbial interactions
- Parasite Biology and Host Interactions
- Methane Hydrates and Related Phenomena
- Aquaculture disease management and microbiota
- Marine Toxins and Detection Methods
- Parasitic Infections and Diagnostics
- Plant Virus Research Studies
- Paleontology and Stratigraphy of Fossils
- Coral and Marine Ecosystems Studies
- Isotope Analysis in Ecology
- Respiratory viral infections research
- Atmospheric chemistry and aerosols
- Food Industry and Aquatic Biology
- Agricultural Research and Practices
- Marine and coastal plant biology
- Invertebrate Immune Response Mechanisms
- Genetic diversity and population structure
- Vibrio bacteria research studies
- Plant Disease Resistance and Genetics
Station Biologique de Roscoff
2014-2024
Sorbonne Université
2013-2024
Centre National de la Recherche Scientifique
2014-2024
Adaptation et Diversité en Milieu Marin
2014-2024
Abstract Background Dinoflagellates are aquatic protists particularly widespread in the oceans worldwide. Some responsible for toxic blooms while others live symbiotic relationships, either as mutualistic symbionts corals or parasites infecting other and animals. harbor atypically large genomes (~ 3 to 250 Gb), with gene organization expression patterns very different from closely related apicomplexan parasites. Here we sequenced analyzed of two early-diverging co-occurring parasitic...
The genus Micromonas comprises phytoplankton that show among the widest latitudinal distributions on Earth, and members of this are recurrently infected by prasinoviruses in contrasted thermal ecosystems. In study, we assessed how temperature influences interplay between main genetic clades prominent microalga their viruses. growth three strains (Mic-A, Mic-B, Mic-C) stability respective lytic viruses (MicV-A, MicV-B, MicV-C) were measured over a range 4-32.5 °C. Similar optima (Topt)...
Abstract Organisms with sexual and asexual reproductive systems benefit from both types of reproduction. Sexual recombination generates new combinations alleles, whereas clonality favours the spread fittest genotype through entire population. Therefore, rate vs. clonal reproduction has a major influence on demography genetic structure natural populations. We addressed effect system populations dinoflagellate Alexandrium minutum . More specifically, we monitored spatiotemporal diversity...
The marine diatom Guinardia delicatula is a cosmopolitan species that dominates seasonal blooms in the English Channel and North Sea. Several eukaryotic parasites are known to induce mortality of this species. Here, we report isolation characterization first viruses infect G. delicatula. Viruses were isolated from Western (SOMLIT-Astan station) during late summer bloom decline A combination laboratory approaches revealed these lytic (GdelRNAV) small tailless particles 35-38 nm diameter...
The multiannual dynamic of the cyst-forming and toxic marine dinoflagellate Alexandrium minutum was studied over a time scale about 150 years by paleoecological approach based on ancient DNA (aDNA) quantification cyst revivification data obtained from two dated sediment cores Bay Brest (Brittany, France). first genetic traces species presence in study area back to 1873 ± 6. Specific aDNA could be quantified newly developed real-time PCR assay upper core layers, which germination (in up...
Parasites are widespread and diverse in oceanic plankton many of them infect single-celled algae for survival. How these parasites develop scavenge energy within the host how cellular organization metabolism is altered remain open questions. Combining quantitative structural chemical imaging with time-resolved transcriptomics, we unveil dramatic morphological metabolic changes marine parasite Amoebophrya (Syndiniales) during intracellular infection, particularly following engulfment...
Marine alveolates (MALVs) are diverse, primarily parasitic micro-eukaryotes that significantly impact marine ecosystems. The life cycles of most MALVs remain elusive and the role sexual reproduction in these organisms is a key question may determine their ecological success. In this study we focus on widespread dinoflagellate parasite bloom-forming dinoflagellates, Amoebophrya. After infection, identified two distinct spores, differing size, ultrastructure, swimming behavior, lifespan, gene...
Abstract As critical primary producers and recyclers of organic matter, the diversity marine protists has been extensively explored by high-throughput barcode sequencing. However, classification short metabarcoding sequences into traditional taxonomic units is not trivial, especially for lineages mainly known their genetic fingerprints. This case widespread Amoebophrya ceratii species complex, parasites dinoflagellate congeners. We used phenotypic characters, applied to 119 individuals...
Nassellaria are marine protists belonging to the Radiolaria lineage (Rhizaria). Their skeleton, made of opaline silica, exhibit an excellent fossil record, extremely valuable in micro-paleontological studies for paleo-environmental reconstruction. Yet, date very little is known about extant diversity and ecology contemporary oceans, most it inferred from their record. Here we present integrative classification based on taxonomical marker genes (18S 28S ribosomal DNA) morphological...
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of that accumulate paralytic toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis encoded in nuclear genome via gene cluster ( sxt ). Toxin production supposedly associated with presence 4th domain sxtA sxtA4 ), one core genes PST cluster. It postulated expression partially constitutive, both transcriptional and post-transcriptional processes...
Abstract. N2 fixation rates were measured in the 0–1000 m layer at 13 stations located open western and central Mediterranean Sea (MS) during PEACETIME cruise (late spring 2017). While spatial variability was not related to Fe, P nor N stocks, surface composition of diazotrophic community indicated a strong longitudinal gradient increasing eastward for relative abundance non-cyanobacterial diazotrophs (NCDs) (mainly γ-Proteobacteria) conversely decreasing photo-heterotrophic group A (UCYN-A)...
Parasites play a role in the control of transient algal blooms, but it is not known whether parasite-mediated selection results coevolution host and parasites over this short time span. We investigated presence between toxic dinoflagellate Alexandrium minutum two naturally occurring endoparasites during blooms lasting month river estuaries, using cross-inoculation experiments across space. Higher parasite abundance was associated with large daily reduction relative A. abundances,...
Summary Protists play a fundamental role in all ecosystems, but we are still far from estimating the total diversity of many lineages, particular highly diverse environments, such as freshwater. Here, survey protist Paraná River using metabarcoding, and applied an approach that includes sequence similarity phylogeny to evaluate degree genetic novelty protists' communities against sequences described reference database PR 2 . We observed ~28% amplicon variants were classified novel according...
Abstract. In the oligotrophic waters of Mediterranean Sea, during stratification period, microbial loop relies on pulsed inputs nutrients through atmospheric deposition aerosols from both natural (e.g., Saharan dust), anthropogenic, or mixed origins. While influence dust processes and community composition is still not fully constrained, extent to which future environmental conditions will affect response known. The impact wet was studied under present (+3 ∘C warming acidification −0.3 pH...
Abstract. In the oligotrophic waters of Mediterranean Sea, during stratification period, microbial loop relies on pulsed inputs nutrients through atmospheric deposition aerosols from both natural (Saharan dust) and anthropogenic origins. While influence dust processes community composition is still not fully constrained, extent to which future environmental conditions will affect response known. The impact wet was studied under present (warming acidification) experiments in 300 L climate...
Collodaria (Retaria) are important contributors to planktonic communities and biogeochemical processes (e.g. the biologic pump) in oligotrophic oceans. Similarly corals, live symbiosis with dinoflagellate algae, a relationship that is thought explain partly their ecological success. In context of global change, robustness symbiotic interaction potential subsequent bleaching events primary interest for oceanic ecosystems functioning. present study, we compared ultrastructure, morphology,...
Photosynthetic picoeukaryotes (PPE) are key components of primary production in marine and freshwater ecosystems. In contrast with those environments, PPE groups have received little attention. this work, we used flow cytometry cell sorting, microscopy metabarcoding to investigate the composition small photosynthetic eukaryote communities from six eutrophic shallow lakes South America, Argentina. We compared total molecular diversity obtained sorted populations as well filtered plankton...
Parasites in the genus Amoebophrya sp. infest dinoflagellate hosts marine ecosystems and can be determining factors demise of blooms, including toxic red tides. These parasitic protists, however, rarely cause total collapse Dinophyceae blooms. Experimental addition parasite-resistant (Alexandrium minutum or Scrippsiella donghaienis) exudates into a well-established host-parasite coculture (Scrippsiella acuminata-Amoebophrya sp.) mitigated parasite success increased survival sensitive host....
Understanding factors that generate, maintain, and constrain host-parasite associations is of major interest to biologists. Although little studied, many extremely virulent micro-eukaryotic parasites infecting microalgae have been reported in the marine plankton. This case for Amoebophrya, a diverse highly widespread group Syndiniales potentially controlling dinoflagellates population. Here, we analyzed time-scale gene expression complete infection cycle two Amoebophrya strains same host...
The increase in emerging harmful algal blooms the last decades has led to an extensive concern understanding mechanisms behind these events. In this paper, we assessed growth of two blooming dinoflagellates (Alexandrium minutum and Heterocapsa triquetra) their susceptibility infection by generalist parasitoid Parvilucifera rostrata under a temperature gradient. differed across range temperatures representative Penzé Estuary (13 22 °C) early summer. A. increased was highest at 19 °C, whereas...
Dinoflagellates are major components of phytoplankton that play critical roles in many microbial food webs, them being hosts countless intracellular parasites. The phototrophic dinoflagellate Scrippsiella acuminata (Dinophyceae) can be infected by the microeukaryotic parasitoids Amoebophrya spp. (Syndiniales), some which primarily target and digest host nucleus. Early digestion nucleus at beginning infection is expected to greatly impact metabolism, inducing knockout organellar machineries...