The increase in marine diseases, particularly in economically important mollusks, is a growing concern. Among them, the Pacific oyster (Crassostrea gigas) production faces challenges from several diseases, such as the Pacific Oyster Mortality Syndrome (POMS) or vibriosis. The microbial education, which consists of exposing the host immune system to beneficial microorganisms during early life stages is a promising approach against diseases.
View Article and Find Full Text PDFThe increasing use of chemicals requires a better understanding of their presence and dynamics in the environment, as well as their impact on ecosystems. The aim of this study was to validate the first steps of an innovative multi-omics approach based on metabolomics and 16S metabarcoding data for analyses of the fate and impact of contaminants in Mediterranean lagoons. Semi-targeted analytical procedures for water and sediment matrices were implemented to assess chemical contamination of the lagoon: forty-six compounds were detected, 28 of which could be quantified in water (between 0.
View Article and Find Full Text PDFWhen two species hybridize, the two parental genomes are brought together and some alleles might interact for the first time. To date, the extent of the transcriptomic changes in first hybrid generations, along with their functional outcome constitute an important knowledge gap, especially in parasite species. Here we explored the molecular and functional outcomes of hybridization in first-generation hybrids between the blood fluke parasites Schistosoma haematobium and S.
View Article and Find Full Text PDFThe Pacific oyster lives in microbe-rich marine coastal systems subjected to rapid environmental changes. It harbours a diversified and fluctuating microbiota that cohabits with immune cells expressing a diversified immune gene repertoire. In the early stages of oyster development, just after fertilization, the microbiota plays a key role in educating the immune system.
View Article and Find Full Text PDFThe pollution of seawater by both biotic (bacteria, viruses) and abiotic contaminants (biocides, pharmaceutical residues) frequently leads to economic losses in aquaculture activities mostly mortality events caused by microbial infection. Advanced Oxidation Processes (AOPs) such as heterogeneous photocatalysis allow the removal of all organic contaminants present in water and therefore could reduce production losses in land-based farms. Oysters in land-based farms such as hatcheries and nurseries suffer from a large number of mortality events, resulting in significant losses.
View Article and Find Full Text PDFBackground: Microbial communities associated with macroorganisms might affect host physiology and homeostasis. Bacteria are well studied in this context, but the diversity of microeukaryotes, as well as covariations with bacterial communities, remains almost unknown.
Methods: To study microeukaryotic communities associated with Planorbidae snails, we developed a blocking primer to reduce amplification of host DNA during metabarcoding analyses.
Background: The Pacific oyster Crassostrea gigas is one of the main cultivated invertebrate species worldwide. Since 2008, oyster juveniles have been confronted with a lethal syndrome known as the Pacific Oyster Mortality Syndrome (POMS). POMS is a polymicrobial disease initiated by a primary infection with the herpesvirus OsHV-1 µVar that creates an oyster immunocompromised state and evolves towards a secondary fatal bacteremia.
View Article and Find Full Text PDFRecent studies have highlighted associations between diseases and host microbiota. It remains extremely challenging - especially under natural conditions - to clarify whether host microbiota promote future infections, or whether changes in host microbiota result from infections. Nonetheless, deciphering between these two processes is essential for highlighting the role of microbes in disease progression.
View Article and Find Full Text PDFCorrectly delimiting species and populations is a prerequisite for studies of connectivity, adaptation and conservation. Genomic data are particularly useful to test species differentiation for organisms with few informative morphological characters or low discrimination of cytoplasmic markers, as in Scleractinians. Here we applied Restriction site Associated DNA sequencing (RAD-sequencing) to the study of species differentiation and genetic structure in populations of Pocillopora spp.
View Article and Find Full Text PDFBackground: Chimeras are genetically mixed entities resulting from the fusion of two or more conspecifics. This phenomenon is widely distributed in nature and documented in a variety of animal and plant phyla. In corals, chimerism initiates at early ontogenic states (larvae to young spat) and results from the fusion between two or more closely settled conspecifics.
View Article and Find Full Text PDFBackground: The interaction of organisms with their surrounding microbial communities influences many biological processes, a notable example of which is the shaping of the immune system in early life. In the Pacific oyster, Crassostrea gigas, the role of the environmental microbial community on immune system maturation - and, importantly, protection from infectious disease - is still an open question.
Results: Here, we demonstrate that early life microbial exposure durably improves oyster survival when challenged with the pathogen causing Pacific oyster mortality syndrome (POMS), both in the exposed generation and in the subsequent one.
A growing awareness of role that microbiota can play in mediating the effects of pathogens on hosts has given rise to the concept of the pathobiome. Recently, we demonstrated that the Pacific oyster mortality syndrome affecting Crassostrea gigas oysters is caused by infection with the Ostreid herpesvirus type 1 (OsHV-1) followed by infection with multiple bacterial taxa. Here we extend the concept of this pathobiome beyond the host species and its bacterial microbiota by investigating how seaweed living in association with oysters influences their response to the disease.
View Article and Find Full Text PDFSchistosomes cause schistosomiasis, the world's second most important parasitic disease after malaria in terms of public health and social-economic impacts. A peculiar feature of these dioecious parasites is their ability to produce viable and fertile hybrid offspring. Originally only present in the tropics, schistosomiasis is now also endemic in southern Europe.
View Article and Find Full Text PDFHost-parasite interaction can result in a strong alteration of the host-associated microbiota. This dysbiosis can affect the fitness of the host; can modify pathogen interaction and the outcome of diseases. is the snail intermediate host of the trematode , the agent of human schistosomiasis, causing hundreds of thousands of deaths every year.
View Article and Find Full Text PDFSpecies usually develop reproductive isolation mechanisms allowing them to avoid interbreeding. These preventive barriers can act before reproduction, "pre-zygotic barriers", or after reproduction, "post-zygotic barriers". Pre-zygotic barriers prevent unfavourable mating, while post-zygotic barriers determine the viability and selective success of the hybrid offspring.
View Article and Find Full Text PDFThe Pacific oyster () has been introduced from Asia to numerous countries around the world during the 20th century. is the main oyster species farmed worldwide and represents more than 98% of oyster production. The severity of disease outbreaks that affect , which primarily impact juvenile oysters, has increased dramatically since 2008.
View Article and Find Full Text PDFHost-microbe interactions play crucial roles in marine ecosystems. However, we still have very little understanding of the mechanisms that govern these relationships, the evolutionary processes that shape them, and their ecological consequences. The holobiont concept is a renewed paradigm in biology that can help to describe and understand these complex systems.
View Article and Find Full Text PDFHybridization is a fascinating evolutionary phenomenon that raises the question of how species maintain their integrity. Inter-species hybridization occurs between certain Schistosoma species that can cause important public health and veterinary issues. In particular hybrids between Schistosoma haematobium and S.
View Article and Find Full Text PDFPacific Oyster Mortality Syndrome (POMS) affects oysters worldwide and causes important economic losses. Disease dynamic was recently deciphered and revealed a multiple and progressive infection caused by the OsHV-1 μVar, triggering an immunosuppression followed by microbiota destabilization and bacteraemia by opportunistic bacterial pathogens. However, it remains unknown if microbiota might participate to protect oysters against POMS, and if microbiota characteristics might be predictive of oyster mortalities.
View Article and Find Full Text PDFPlanorbidae snails are the intermediate host for the trematode parasite of the genus, which is responsible for schistosomiasis, a disease that affects both humans and cattle. The microbiota for has already been described as having an effect on host/parasite interactions, specifically through immunological interactions. Here, we sought to characterize the microbiota composition of seven Planorbidae species and strains.
View Article and Find Full Text PDFspecies cause infectious diseases in humans and animals, but they can also live as commensals within their host tissues. How subverts the host defenses to mount a successful infection remains poorly understood, and this knowledge is critical for predicting and managing disease. Here, we have investigated the cellular and molecular mechanisms underpinning infection and colonization of 2 virulent species in an ecologically relevant host model, oyster, to study interactions with marine species.
View Article and Find Full Text PDFIron (Fe) is a limiting nutrient in large regions of the ocean, but the strategies of prokaryotes to cope with this micronutrient are poorly known. Using a gene-specific approach from metatranscriptomics data, we investigated seven Fe-related metabolic pathways in microbial communities from high nutrient low chlorophyll and naturally Fe-fertilized waters in the Southern Ocean. We observed major differences in the contribution of prokaryotic groups at different taxonomic levels to transcripts encoding Fe-uptake mechanisms, intracellular Fe storage and replacement and Fe-related pathways in the tricarboxylic acid (TCA) cycle.
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