Maria-Cristina Ciobanu

French National Centre for Scientific Research | CNRS

Apusomonads are cosmopolitan bacterivorous biflagellate protists usually gliding on freshwater and marine sediment or wet soils. These nanoflagellates form a sister lineage to opisthokonts and may have retained ancestral features helpful to understanding the early evolution of this large supergroup. Although molecular environmental analyses indicat...

A unicellular cyanobacterium, strain VI4D9, was isolated from thermophilic microbial mats thriving in a hot spring of the Ahousaht territory of Vancouver Island, Canada. The cells were elongated rods (5.1 micrometers in length and 1.2 micrometers in width on average). Their UV to visible absorption spectra revealed that they contain chlorophyll a,...

Early eukaryotic evolution is poorly understood. Lacking a fossil record, comparative genomics allows us to reconstruct the evolutionary history of species and their genes, infer the order of evolutionary changes and their functional implications. Thanks to sequencing transcriptomes and genomes of protists, it becomes possible to unveil the evoluti...

The supergroup Holomycota, composed of Fungi and several related lineages of unicellular organisms (Nucleariida, Rozellida, Microsporidia, and Aphelida), represents one of the major branches in the phylogeny of eukaryotes. Nevertheless, except for the well-established position of Nucleariida as the first holomycotan branch to diverge, the relations...

Proliferation of selfish genetic elements has led to significant genome size expansion in plastid and mitochondrial genomes of various eukaryotic lineages. Within the red algae, such expansion events are only known in the plastid genomes of the Proteorhodophytina, a highly diverse group of mesophilic microalgae. By contrast, they have never been de...

Supplementary data set to "Deglacial to Holocene environmental changes in the northern Ligurian Sea: The dual influence of regional climate variability and large-scale intermediate Mediterranean circulation". https://doi.org/10.1016/j.palaeo.2021.110500

The sedimentary archives of the Mediterranean Sea record periodic deposits of organic-rich deposits, called sapropels in the eastern basin and organic-rich layers (ORL) in the western basin. Changes in both the Mediterranean circulation and inputs of fresh water through borderlands rivers under more humid climate, are important mechanisms to explai...

It is generally assumed that viruses outnumber cells on Earth by at least tenfold. Virus-to-microbe ratios (VMR) are largely based on fluorescently-labelled viral-like particles (VLPs) counts. However, these exclude cell-infecting lytic and lysogenic viruses and potentially include many false positives, e.g. DNA-containing membrane vesicles, gene-t...

The goals of the project HOTVIR include both the microbial and geochemical characterization of pools and hot springs within the Saint Paul Island and the Kerguelen Archipelago. We particularly study the diversity and the ecological significance of thermophilic microorganisms and viruses present in these extreme environments.

The islands of The French Austral and Antarctic Territories are situated in the South Indian Ocean. Located on a geothermal hotspot, the St Paul Island is an extinct volcano, partially submerged in the sea, that harbors hot springs. These shallow submarine hot springs range between 75°C-85°C degrees in temperature and are of neutral pH (6-7). As th...

The goals of the project HOTVIR include both the microbial and geochemical characterization of pools and hot springs within the Saint Paul Island and the Kerguelen Archipelago. We particularly study the diversity and the ecological significance of thermophilic microorganisms and viruses present in these extreme environments.

Aphelids remain poorly known parasitoids of algae and have recently raised considerable interest due to their phylogenetic position at the base of Fungi. Accordingly, aphelids may still display some ancestral characters that were subsequently lost in the fungal lineage. Some mycologists consider the aphelids as Fungi. However, unlike Fungi, they ar...

Is there a mesopelagic protist fauna composed of species different from that of the overlying surface community? Does the mesopelagic community show seasonal changes in abundances and species composition? We addressed these questions by considering 3 distinct groups in which species identification is relatively unambiguous: tintinnid ciliates, phae...

The subsurface realm is colonized by microbial communities to depths of 41000 meters below the seafloor (m.b.sf.), but little is known about overall diversity and microbial distribution patterns at the most profound depths. Here we show that not only Bacteria and Archaea but also Eukarya occur at record depths in the subseafloor of the Canterbury B...

The deep subseafloor, extending from a few centimeters below the sediment surface to several hundred meters into sedimentary deposits, constitutes the deep biosphere and harbors an unexpected microbial diversity. Several studies have described occurrence, turnover, activity and function of subseafloor prokaryotes, whereas subsurface eukaryotic comm...

A novel halophilic bacterium, strain RHS90T, was isolated from marine sediments from the Gulf of Lions, in the Mediterranean Sea. Its metabolic and physiological characteristics were examined under various cultural conditions, including exposure to stressful ones (oligotrophy, high pressure and high concentrations of metals). Based on phylogenetic...

Subsurface sediments of the Sonora Margin (Guaymas Basin), located in proximity of active cold seep sites were explored. The taxonomic and functional diversity of bacterial and archaeal communities were investigated from 1 to 10 meters below the seafloor. Microbial community structure and abundance and distribution of dominant populations were asse...

The subsurface realm is colonized by microbial communities to depths of >1000 meters below the seafloor (m.b.sf.), but little is known about overall diversity and microbial distribution patterns at the most profound depths. Here we show that not only Bacteria and Archaea but also Eukarya occur at record depths in the subseafloor of the Canterbury B...

Hematite, the most abundant mineral in Iron Oxide Copper Gold (IOCG) deposits in the Gawler Craton of South Australia, may incorporate significant amounts of U, W, Mo and radiogenic Pb. These elements are concentrated in hematite grains which display either oscillatory and/or sectorial compositional zoning, or are porous. The presence of U and Pb r...

A novel Gram-negative, facultative anaerobic, heterotrophic bacterium, designated 306T, was isolated from near surface sediments of the Gulf of Lions, in the Mediterranean Sea. Strain 306T grew at temperatures between 4 and 30°C (optimum 17-22°C), from pH 6.5 to 9.0 (optimum 7.0-9.0) and between 0.5 and 6.0% (w/v) NaCl (optimum 2.0%). Its DNA G+C c...

An interdisciplinary study was conducted to evaluate the relationship between geological and paleontological parameters and the bacterial and archaeal community structure of two contrasted subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lions). Since both depositional environments were well-documented in this area, larg...

An interdisciplinary study was conducted to evaluate the relationship between geological and paleontological parameters and the bacterial and archaeal community structure of two contrasted subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lions). Since both depositional environments were well-documented in this area, larg...

Extracting DNA from deep subsurface sediments is challenging given the complexity of sediments types, low biomasses, resting structures (spores, cysts) frequently encountered in deep sediments, and the potential presence of enzymatic inhibitors. Promising results for cell lysis efficiency were recently obtained by use of a cryogenic mill (Lipp et a...

The abundances of the thermophilic microbial communities and the VLPs associated to them are: a prokaryotic abundance ranging from 0.07 x 106 to 6.7 x 106 cells/ml and a VLP abundance ranging from 0.04 x 106 to 2.2 x 106 VLPs/ml. These results are similar the data available today, indicating prokaryotic and VLP abundances of the order of 104 – 106...

The observations on each level (raw sample/enrichment culture/ isolates) reveal classical phage morphologies (belonging to Caudovirales) as well as a new type of phage morphology. The presence of vesicules, similar to those recently described by Soler et al * were also observed in both anaerobic enrichment cultures and archaeal isolates.

Expedition 317 investigated the record of global sea-level change (eustasy) within continental margin sedimentary sequences and how eustasy interacts with local forcing to produce preserved sedimentary architectures. The Canterbury Basin, on the eastern margin of the South Island of New Zealand, was selected to study these complex interactions beca...

Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence...

Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence...

A novel thermophilic, anaerobic and organotrophic bacterium, designated strain MC3T, was isolated from a coastal thermal spring on Ile Saint-Paul in the Southern Indian Ocean. Cells of strain MC3T were motile rods, 0.8-1.0 microm wide and 1.0-2.4 microm long during exponential phase and up to 7.0 microm long during stationary phase. Strain MC3T was...

Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence...