Yves Desdevises

Sorbonne Université | UPMC · Observatoire océanologique de Banyuls sur mer

the data inferred from populations, infra-and component communities of parasites and the application of a macroecological approach in the analysis of complex and frequently hidden relationships in host-parasite systems. This comparative analysis draws on parasite data across regions and host species at different organizational (population vs. commu...

Background Animal-associated microbial communities appear to be key factors in host physiology, ecology, evolution and its interactions with the surrounding environment. Teleost fish have received relatively little attention in the study of surface-associated microbiota. Besides the important role of microbiota in homeostasis and infection preventi...

Monogeneans are highly diverse fish ectoparasites with a direct life cycle, widely distributed and are known to generally display strict host specificity. Factors related to the hosts and the parasite have been suggested to explain this high specificity. Monogeneans have also been observed to colonize fish species not in their natural host range un...

On the occasion of the 200th anniversary of the birth of Henri de Lacaze-Duthiers, one of the most curious and active scientific minds among 19th century naturalists, this article retraces his scientific career and recalls the long-term changes he made in the practice of science: promotion of experimental zoology, foundation of a modern scientific...

The rate of failure of French students during their first years at university is substantial, with only 42% graduating in the expected three or 4 years. As a result, French universities have called for a “pedagogical transformation” encouraging innovative teaching practices to improve undergraduate students’ academic success, notably the introducti...

Almost sixty years ago, Bdellovibrio and like organisms (BALOs) were discovered as the first obligate bacterial predators of other bacteria known to science. Since then, they were shown to be diverse and ubiquitous in the environment, and to bear astonishing ecological, physiological, and metabolic capabilities. The last decade has seen important s...

The diversity and relationships between Archaea and Bacteria remain poorly examined in lakes. Using universal primers targeting 16S rRNA gene via Hiseq sequencing, we explored archaeal and bacterial diversity, structure and relationships in the largest natural deep lake in Western Europe, i.e., Lake Geneva. Despite being less diverse than bacteria,...

Medlin tested multiple outgroups with 18S rRNA dataset and found that haptophytes, ciliates, prasinophytes, and chlorophytes recovered monophyletic Coscinodiscophyceae, Mediophyceae, Bacillariophyceae (CMB) with strong BT (bootstrap) support. Theriot et al. added six plastid genes to the diatom dataset but with only one outgroup, Bolidomonas, and o...

Microorganisms are an important component in shaping the evolution of hosts and as such, the study of bacterial communities with molecular techniques is shedding light on the complexity of symbioses between bacteria and vertebrates. Teleost fish are a heterogeneous group that live in a wide variety of habitats, and thus a good model group to invest...

Microbial communities, which drive the major ecosystem functions, are composed by a wide range of interacting species. Understanding how microbial communities are structured and the underlying processes is a crucial task for interpreting ecosystem response to global change but it is challenging as microbial interactions cannot usually be directly o...

Virus-microbe interactions in the ocean are commonly described by “boom and bust” dynamics, whereby a numerically dominant microorganism is lysed and replaced by a virus-resistant one. Here, we isolated a microalga strain and its infective dsDNA virus whose dynamics are characterized instead by parallel growth of both the microalga and the virus. E...

When considering microbial biotic interactions, viruses as well as eukaryotic grazers are known to be important components of aquatic microbial food webs. It might be the same for bacterivorous bacteria but these groups have been comparatively less studied. This is typically the case of the Bdellovibrio and like organisms (BALOs), which are obligat...

The epicontinental fauna of the Iberian Peninsula is strongly influenced by its geographical history. As the possibilities for dispersion of organisms into and from this region were (and still are) limited, the local fauna consists almost exclusively of endemic species. Almost all Iberian freshwater fishes of the families Leuciscidae and Cyprinidae...

Myctophids are among the most abundant mesopelagic teleost fishes worldwide. They are dominant in the Southern Ocean, an extreme environment where they are important both as consumers of zooplankton as well as food items for larger predators. Various studies have investigated myctophids diet, but no data is yet available regarding their associated...

The study of host–parasite coevolution is one of the cornerstones of evolutionary biology. The majority of fish ectoparasites belonging to the genus Dactylogyrus (Monogenea) exhibit a high degree of host specificity. Therefore, it is expected that their evolutionary history is primarily linked with the evolutionary history of their cyprinoid fish h...

Next-generation sequencing methods are increasingly used to identify eukaryotic, unicellular and multicellular symbiont communities within hosts. In this study, we analyzed the non-specific reads obtained during a metabarcoding survey of the bacterial communities associated to three different tissues collected from 13 wild Mediterranean teleost fis...

Phytoplankton-virus interactions are major determinants of geochemical cycles in the oceans. Viruses are responsible for the redirection of carbon and nutrients away from larger organisms back towards microorganisms via the lysis of microalgae in a process coined the "viral shunt". Virus-host interactions are generally expected to follow "boom and...

Parasites exhibiting a high degree of host specificity are expected to be intimately associated with their hosts. Therefore, the evolution of host-specific parasites is at least partially shaped by the evolutionary history and distribution of such hosts. Gill ectoparasites of Dactylogyrus (Monogenea) are specific to cyprinid fish. In the present st...

The green picoalgal genus Micromonas is broadly distributed in estuaries, coastal marine habitats and open oceans, from the equator to the poles. Phylogenetic, ecological and genomic analyses of culture strains and natural populations have suggested that this cosmopolitan genus is composed of several cryptic species corresponding to genetic lineage...

Tiny photosynthetic microorganisms that form the picoplankton (between 0.3 and 3 μm in diameter) are at the base of the food web in many marine ecosystems, and their adaptability to environmental change hinges on standing genetic variation. Although the genomic and phenotypic diversity of the bacterial component of the oceans has been intensively s...

Phylogenies of the diatoms have largely been inferred from SSU rDNA sequences. Because previously published SSU rDNA topologies of araphid pennate diatoms have varied, a supertree was constructed in order to summarize those trees and used to guide further analyses where problems arose. As previously seen with the SSU trees, araphid diatoms were div...

High-throughput sequencing of Prasinovirus DNA polymerase and host green algal (Mamiellophyceae) ribosomal RNA genes was used to analyse the diversity and distribution of these taxa over a ∼10,000 km latitudinal section of the Indian Ocean. New viral and host groups were identified among the different trophic conditions observed, and highlighted th...

Microbes are phylogenetically (Archaea, Bacteria, Eukarya, and viruses) and functionally diverse. They colonize highly varied environments and rapidly respond to and evolve as a response to local and global environmental changes, including those induced by pollutants resulting from human activities. This review exemplifies the Microbial Ecology EC2...

The genus Micromonas comprises distinct genetic clades that commonly dominate eukaryotic phytoplankton community from polar to tropical waters. This phytoplankter is also recurrently infected by abundant and genetically diverse prasinoviruses. Here we report on the interplay between prasinoviruses and Micromonas with regards to the genetic diversit...

Viruses display strong interactions with their hosts, from physiological and ecological point of views, often leading to strict patterns of host specificity. It is then tempting to consider that viruses evolve in the same way as their hosts, behaving more or less like hosts' characters. However, the cospeciation between viruses and their hosts, tha...

Microbes are phylogenetically (Archaea, Bacteria, Eukarya, and viruses) and functionally diverse. They colonize highly varied environments and rapidly respond to and evolve as a response to local and global environmental changes, including those induced by pollutants resulting from human activities. This review exemplifies the Microbial Ecology EC2...

In the last three decades, comparative analysis across species has been widely used to uncover patterns of correlated evolution among traits, or between phenotypic traits and environment (i.e. adaptation). The seminal paper by Felsenstein in 1985 has at the same time clarified the need to account for phylogeny in cross-species analyses, and propose...

Numerous seawater lagoons punctuate the southern coastline of France. Exchanges of seawater between these lagoons and the open sea are limited by narrow channels connecting them. Lagoon salinities vary according to evaporation and to the volume of freshwater arriving from influent streams, whose nutrients also promote the growth of algae. We compar...

Numerous studies have investigated cospeciation (or cophylogeny) in various host-symbiont systems, and different patterns were inferred, from strict cospeciation where symbiont phylogeny mirrors host phylogeny, to complete absence of correspondence between trees. The degree of cospeciation is generally linked to the level of host specificity in the...

Viruses strongly influence the ecology and evolution of their eukaryotic hosts in the marine environment, but little is known about their diversity and distribution. Prasinoviruses infect an abundant and widespread class of phytoplankton, the Mamiellophyceae, and thereby exert a specific and important role in microbial ecosystems. However, molecula...

Numerous studies have investigated cospeciation between parasites and their hosts, but there have been few studies concerning parasitoids and insect hosts. The high diversity and host specialization observed in Anicetus species suggest that speciation and adaptive radiation might take place with species diversification in scale insect hosts. Here w...

It is widely accepted that disease interactions between cultured and wild fish occur repeatedly, although reported cases have mainly relied just on the observation of similar symptoms in affected populations. Whether there is an explicit pathogen transfer between fish stocks, or each develops its own pathogen population, has been insufficiently stu...

Mismatch distribution of internal transcribed spacer 1 (ITS1) haplotypes of Furnestinia echeneis sampled from Adriatic wild sea bream (a), Adriatic cage sea bream (b) and western Mediterranean wild sea bream (c). (TIF)

Number of COI haplotypes obtained in each population and changes in base composition. (DOC)

Morphometric variables (landmarks) measured on the sclerified parts of the opisthohaptor of Furnestinia echeneis individuals: a, a’ - total length of dorsal and ventral hook; b, b’ - point length of dorsal and ventral hook; c, c’ - blade opening of dorsal and ventral hook; d - distance between grip and hilt; e - grip length; f - hilt length; mvb...

Mismatch distribution of cytochrome c oxidase I (COI) haplotypes of Furnestinia echeneis sampled from Adriatic wild sea bream (a), Adriatic cage sea bream (b) and western Mediterranean wild sea bream (c). (TIF)

Sampling localities, hosts and descriptive statistics of genetic diversity of Furnestinia echeneis , based on ITS1 sequence data. (DOC)

Analysis of molecular variance (AMOVA) for Furnestinia echeneis populations, based on mitochondrial COI and ITS1 (in italic) sequences data. (DOC)

Tajima's D , Fu's Fs statistics, corresponding P values and mismatch distribution parameter estimates for Furnestinia echeneis based on COI sequence data. (DOC)

Sampling localities, hosts and descriptive statistics of genetic diversity of Furnestinia echeneis , based on COI sequence data. (DOC)

Furnestinia echeneis samples, with geographic area of sampling, source, host category and allocated GenBank accession numbers. (DOC)

Number of ITS1 haplotypes obtained in each population with changes in base composition. (DOC)

Tajima's D , Fu's Fs statistics, corresponding P values and mismatch distribution parameter estimates for Furnestinia echeneis based on ITS1 sequence data. (DOC)

Nucleo-cytoplasmic large DNA viruses (NCLDVs) constitute a group of eukaryotic viruses that can have crucial ecological roles in the sea by accelerating the turnover of their unicellular hosts or by causing diseases in animals. To better characterize the diversity, abundance and biogeography of marine NCLDVs, we analyzed 17 metagenomes derived from...

Phylogenetic diversity in the Phycodnaviridae (double-stranded DNA viruses infecting photosynthetic eukaryotes) is most often studied using their DNA polymerase gene (PolB). This gene and its translated protein product can harbor a selfish genetic element called an "intein" that disrupts the sequence of the host gene without affecting its activity....

Viruses in Earth's aquatic environment outnumber all other forms of life and carry a vast reservoir of genetic information. A large proportion of the characterized viruses infecting eukaryotic algae are large double-stranded DNA viruses, each of their genomes carrying more than a hundred genes, but only a minority of their genes resemble genes with...

Proteolysis of sperm histones in the sea urchin male pronucleus is the consequence of the activation at fertilization of a maternal cysteine protease. We previously showed that this protein is required for male chromatin remodelling and for cell-cycle progression in the newly formed embryos. This enzyme is present in the nucleus of unfertilized egg...

Symbiotic relationships are widespread in nature and are fundamental for ecosystem functioning and the evolution of biodiversity. In marine environments, photosymbiosis with microalgae is best known for sustaining benthic coral reef ecosystems. Despite the importance of oceanic microbiota in global ecology and biogeochemical cycles, symbioses are p...