Suchergebnisse

6 pages, 1 figure, 2 tables. ; A focused ultrastructural study of Marteilia spp. found in cultured Ostrea edulis, Mytilus edulis and Mytilus galloprovincialis from France and Spain was conducted with emphasis placed on haplosporosomes, striated plate-like inclusions and spore wall morphology. Two types of haplosporosome were identified, sphaeroid and oblate, which were common to the parasite in all 3 host species. A total of 492 haplosporosomes were measured; those from the Marteilia sp. in Mytilus spp. were marginally smaller than those in Ostrea edulis. Spore wall morphology was found to vary depending on the state of maturity of the parasite‹the more mature the parasite, the thicker the wall surrounding it. It is suggested that the current criteria used to distinguish M. maurini from M. refringens are invalid and that M. maurini was relegated to a junior synonym of M. refringens. ; This work was supported by European Union FAIR contract 94C 85/13. ; Peer reviewed

8 pages, 1 figure, 7 tables. ; The protozoan parasite Bonamia ostreae (Pichot et al., 1980) is a serious pathogen of the native European flat oyster Ostrea edulis. Field and laboratory based experiments were carried out in Ireland and Spain to investigate the susceptibility to this protozoan of the Pacific oyster Crassostrea gigas, the mussels Mytilus edulis and Mytilus galloprovincialis, the European native clam Ruditapes decussatus and the Manila clam Ruditapes philippinarum. Their ability to act as vectors or intermediate hosts was also investigated. The study corroborated previous findings that demonstrated that flat oysters can be successfully infected both naturally in the field and experimentally in the laboratory, and the pathogen can be transmitted directly between flat oysters in the laboratory. However, the other bivalves tested could not be infected with the parasite either naturally or experimentally, and these bivalves did not appear to act as vectors or intermediate hosts for the parasite. These results have implications for movements of bivalves between areas within the European Union. ; This work was supported by European Union FAIR contract 94C 85/13. ; Peer reviewed

Microcell parasites have independently evolved in several eukaryotic lineages and are increasingly recognized as important and emerging pathogens of diverse hosts, including species of economic importance subject to international legislation concerning the trading of aquatic animals [1-3]. The microcell Mikrocytos mackini causes Denman Island disease of oysters and represents one of the most genetically divergent eukaryotes known. Mikrocytos has remained an isolated lineage with a limited distribution. We investigated two emerging diseases of juvenile crabs and oysters from the UK using massively parallel sequencing and targeted primer approaches to reveal that their causative agents are highly divergent lineages related to M. mackini (Paramikrocytos canceri n. gen. et n. sp. and M. mimicus sp. nov., respectively). We demonstrate a major new globally distributed parasite radiation (Mikrocytida ord. nov.) with phylogenetic affinities to the commercially important haplosporidian parasites of invertebrates. Mikrocytids have eluded detection because of their small size, intracellular habit, and extreme sequence divergence. P. canceri was frequently detected in a range of shoreline invertebrates, demonstrating that these newly recognized parasites are in fact common, diverse, and widespread and should be considered when assessing the risks of aquaculture activities, invasive species spread, and movements of ballast water and sediments with associated invertebrates. Video Abstract © 2014 The Authors.

Microcell parasites have independently evolved in several eukaryotic lineages and are increasingly recognized as important and emerging pathogens of diverse hosts, including species of economic importance subject to international legislation concerning the trading of aquatic animals [1; 2 ; 3]. The microcell Mikrocytos mackini causes Denman Island disease of oysters and represents one of the most genetically divergent eukaryotes known. Mikrocytos has remained an isolated lineage with a limited distribution. We investigated two emerging diseases of juvenile crabs and oysters from the UK using massively parallel sequencing and targeted primer approaches to reveal that their causative agents are highly divergent lineages related to M. mackini (Paramikrocytos canceri n. gen. et n. sp. and M. mimicus sp. nov., respectively). We demonstrate a major new globally distributed parasite radiation (Mikrocytida ord. nov.) with phylogenetic affinities to the commercially important haplosporidian parasites of invertebrates. Mikrocytids have eluded detection because of their small size, intracellular habit, and extreme sequence divergence. P. canceri was frequently detected in a range of shoreline invertebrates, demonstrating that these newly recognized parasites are in fact common, diverse, and widespread and should be considered when assessing the risks of aquaculture activities, invasive species spread, and movements of ballast water and sediments with associated invertebrates. ; ISSN:0960-9822 ; ISSN:1879-0445

Marine environmental monitoring is undertaken to provide evidence that environmental management targets are being met. Moreover, monitoring also provides context to marine science and over the last century has allowed development of a critical scientific understanding of the marine environment and the impacts that humans are having on it. The seas around the UK are currently monitored by targeted, impact-driven, programmes (e.g., fishery or pollution based monitoring) often using traditional techniques, many of which have not changed significantly since the early 1900s. The advent of a new wave of automated technology, in combination with changing political and economic circumstances, means that there is currently a strong drive to move toward a more refined, efficient, and effective way of monitoring. We describe the policy and scientific rationale for monitoring our seas, alongside a comprehensive description of the types of equipment and methodology currently used and the technologies that are likely to be used in the future. We contextualize the way new technologies and methodologies may impact monitoring and discuss how whole ecosystems models can give an integrated, comprehensive approach to impact assessment. Furthermore, we discuss how an understanding of the value of each data point is crucial to assess the true costs and benefits to society of a marine monitoring programme.