Warming effects on the life cycles of two parasitic copepods with different invasion histories.

Climate change may exacerbate the impact of invasive parasites from warmer climates through pre-existing temperature adaptations. We investigated temperature impacts on two closely related marine parasitic copepod species that share the blue mussel () as host: has invaded the system from a warmer climate <20 years ago, whereas its established congener has had >90 years to adapt. In laboratory experiments with temperatures 10-26°C, covering current and future temperatures as well as heat waves, the development of both life cycle stages of both species accelerated with increasing temperature.

Evidence for immune priming specificity and cross-protection against sympatric and allopatric Vibrio splendidus strains in the oyster Magalana (Crassostrea) gigas.

Infections with pathogenic Vibrio strains are associated with high summer mortalities of Pacific oysters Magalana (Crassostrea) gigas, affecting production worldwide. This raises the question of how M. gigas cultures can be protected against deadly Vibro infection.

Combined effects of temperature and emersion-immersion cycles on metabolism and bioenergetics of the Pacific oyster Crassostrea (Magallana) gigas.

Life on tidal coasts presents physiological major challenges for sessile species. Fluctuations in oxygen and temperature can affect bioenergetics and modulate metabolism and redox balance, but their combined effects are not well understood. We investigated the effects of intermittent hypoxia (12h/12h) in combination with different temperature regimes (normal (15 °C), elevated (30 °C) and fluctuating (15 °C water/30 °C air)) on the Pacific oyster Crassostrea (Magallana) gigas.

FicD genes in invertebrates: A tale of transposons, pathogenic and integrated viruses.

Many gene families are shared across the tree of life between distantly related species because of horizontal gene transfers (HGTs). However, the frequency of HGTs varies strongly between gene families and biotic realms suggesting differential selection pressures and functional bias. One gene family with a wide distribution are FIC-domain containing enzymes (FicDs).

Effect of predation risk on parasite transmission from first to second intermediate trematode hosts.

Predators can affect parasite-host interactions when directly preying on hosts or their parasites. However, predators may also have non-consumptive indirect effects on parasite-host interactions when hosts adjust their behaviour or physiology in response to predator presence. In this study, we examined how chemical cues from a predatory marine crab affect the transmission of a parasitic trematode from its first (periwinkle) to its second (mussel) intermediate host.

Environmental vibrio phage-bacteria interaction networks reflect the genetic structure of host populations.

Phages depend on their bacterial hosts to replicate. The habitat, density and genetic diversity of host populations are therefore key factors in phage ecology, but our ability to explore their biology depends on the isolation of a diverse and representative collection of phages from different sources. Here, we compared two populations of marine bacterial hosts and their phages collected during a time series sampling program in an oyster farm.

Phage-host coevolution in natural populations.

Coevolution between bacteriophages (phages) and their bacterial hosts occurs through changes in resistance and counter-resistance mechanisms. To assess phage-host evolution in wild populations, we isolated 195 Vibrio crassostreae strains and 243 vibriophages during a 5-month time series from an oyster farm and combined these isolates with existing V. crassostreae and phage isolates.

Viral Decoys: The Only Two Herpesviruses Infecting Invertebrates Evolved Different Transcriptional Strategies to Deflect Post-Transcriptional Editing.

The highly versatile group of Herpesviruses cause disease in a wide range of hosts. In invertebrates, only two herpesviruses are known: the malacoherpesviruses HaHV-1 and OsHV-1 infecting gastropods and bivalves, respectively. To understand viral transcript architecture and diversity we first reconstructed full-length viral genomes of HaHV-1 infecting and OsHV-1 infecting by DNA-seq.

Windows of opportunity: Ocean warming shapes temperature-sensitive epigenetic reprogramming and gene expression across gametogenesis and embryogenesis in marine stickleback.

Rapid climate change is placing many marine species at risk of local extinction. Recent studies show that epigenetic mechanisms (e.g.

Microbiome response differs among selected lines of Sydney rock oysters to ocean warming and acidification.

Oyster microbiomes are integral to healthy function and can be altered by climate change conditions. Genetic variation among oysters is known to influence the response of oysters to climate change and may ameliorate any adverse effects on oyster microbiome; however, this remains unstudied. Nine full-sibling selected breeding lines of the Sydney rock oyster (Saccostrea glomerata) were exposed to predicted warming (ambient = 24°C, elevated = 28°C) and ocean acidification (ambient pCO2 = 400, elevated pCO2 = 1000 µatm) for 4 weeks.

Molecular Targets for Coevolutionary Interactions Between Pacific Oyster Larvae and Their Sympatric .

Bacteria of the genus are the most predominant infectious agents threatening marine wildlife and aquaculture. Due to the large genetic diversity of these pathogens, the molecular determinants of virulence are only poorly understood. Furthermore, studies tend to ignore co-evolutionary interactions between different host populations and their locally encountered communities.

Global invasion genetics of two parasitic copepods infecting marine bivalves.

Invasive species, and especially invasive parasites, represent excellent models to study ecological and evolutionary mechanisms in the wild. To understand these processes, it is crucial to obtain more knowledge on the native range, invasion routes and invasion history of invasive parasites. We investigated the consecutive invasions of two parasitic copepods (Mytilicola intestinalis and Mytilicola orientalis) by combining an extensive literature survey covering the reported putative native regions and the present-day invaded regions with a global phylogeography of both species.

Selection of Vibrio crassostreae relies on a plasmid expressing a type 6 secretion system cytotoxic for host immune cells.

Pacific oyster mortality syndrome affects juveniles of Crassostrea gigas oysters and threatens the sustainability of commercial and natural stocks of this species. Vibrio crassostreae (V. crassostreae) has been repeatedly isolated from diseased animals, and the majority of the strains have been demonstrated to be virulent for oysters.

An Evolutionary Perspective of Dopachrome Tautomerase Enzymes in Metazoans.

Melanin plays a pivotal role in the cellular processes of several metazoans. The final step of the enzymically-regulated melanin biogenesis is the conversion of dopachrome into dihydroxyindoles, a reaction catalyzed by a class of enzymes called dopachrome tautomerases. We traced (DCT) and (DCE) genes throughout metazoans and we could show that only one class is present in most of the phyla.

How invasive oysters can affect parasite infection patterns in native mussels on a large spatial scale.

There are surprisingly few field studies on the role of invasive species on parasite infection patterns in native hosts. We investigated the role of invasive Pacific oysters (Magallana gigas) in determining parasite infection levels in native blue mussels (Mytilus edulis) in relation to other environmental and biotic factors. Using hierarchical field sampling covering three spatial scales along a large intertidal ecosystem (European Wadden Sea), we found strong spatial differences in infection levels of five parasite species associated with mussels and oysters.

Within-generation and transgenerational plasticity of mate choice in oceanic stickleback under climate change.

Plasticity, both within and across generations, can shape sexual traits involved in mate choice and reproductive success, and thus direct measures of fitness. Especially, transgenerational plasticity (TGP), where parental environment influences offspring plasticity in future environments, could compensate for otherwise negative effects of environmental change on offspring sexual traits. We conducted a mate choice experiment using stickleback ( Gasterosteus aculeatus) with different thermal histories (ambient 17°C or elevated 21°C) within and across generations under simulated ocean warming using outdoor mesocosms.

Infection by invasive parasites increases susceptibility of native hosts to secondary infection via modulation of cellular immunity.

Parasite spillover from invasive aliens to native species increases the risk of disease emergence within native biota-either by direct harm to the new host or by indirect effects like increased risks of secondary infection. One example for such a detrimental effect is the parasitic copepod Mytilicola intestinalis that infected blue mussels Mytilus edulis after being introduced into the North Sea in the early 20th century. Since 1949, the parasite was blamed for multiple mass mortalities of infested blue mussels but evidence for a direct causal involvement of M.

Pandemic GII.4 Sydney and Epidemic GII.17 Kawasaki308 Noroviruses Display Distinct Specificities for Histo-Blood Group Antigens Leading to Different Transmission Vector Dynamics in Pacific Oysters.

Noroviruses are the major cause of foodborne outbreaks of acute gastroenteritis, which are often linked to raw oyster consumption. Previous studies have suggested histo-blood group antigens (HBGA)-like structures in the oyster tissues as ligands for norovirus binding and persistence. To better understand how oysters function as vectors for the most common human noroviruses, we first tested the ability of the norovirus strains GI.

Cryptic invasion of a parasitic copepod: Compromised identification when morphologically similar invaders co-occur in invaded ecosystems.

Despite their frequent occurrence and strong impacts on native biota, biological invasions can long remain undetected. One reason for this is that an invasive species can be morphologically similar to either native species or introduced species previously established in the same region, and thus be subject to mistaken identification. One recent case involves congeneric invasive parasites, copepods that now infect bivalve hosts along European Atlantic coasts, after having been introduced independently first from the Mediterranean Sea (Mytilicola intestinalis Steuer, 1902) and later from Japan (Mytilicola orientalis Mori, 1935).

Dual transcriptomics reveals co-evolutionary mechanisms of intestinal parasite infections in blue mussels Mytilus edulis.

On theoretical grounds, antagonistic co-evolution between hosts and their parasites should be a widespread phenomenon but only received little empirical support so far. Consequently, the underlying molecular mechanisms and evolutionary steps remain elusive, especially in nonmodel systems. Here, we utilized the natural history of invasive parasites to document the molecular underpinnings of co-evolutionary trajectories.

Naturally acidified habitat selects for ocean acidification-tolerant mussels.

Ocean acidification severely affects bivalves, especially their larval stages. Consequently, the fate of this ecologically and economically important group depends on the capacity and rate of evolutionary adaptation to altered ocean carbonate chemistry. We document successful settlement of wild mussel larvae () in a periodically CO-enriched habitat.

Population-specific genotype x genotype x environment interactions in bacterial disease of early life stages of Pacific oyster larvae.

The consequences of emerging marine diseases on the evolutionary trajectories of affected host populations in the marine realm are largely unexplored. Evolution in response to natural selection depends on the genetic variation of the traits under selection and the interaction of these traits with the environment (GxE). However, in the case of diseases, pathogen genotypes add another dimension to this interaction.