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perkinsus marinus in crassostrea gigas in the gulf of california.to determine the agent responsible for the massive mortalities of the pacific oyster crassostrea gigas in northwest mexico, 30 oysters were sampled after a severe mortality event in 2006 along the sonoran coast. histological analyses revealed the presence of a protozoan and ray's fluid thioglycollate medium (rftm) assays showed the presence of perkinsus sp., identified as p. marinus from the dna sequence of the internal transcribed spacer (its) of the ribosomal rna (rrna) gene complex. pcr analy ...201020481094
marteilia spp. parasites in bivalves: a revision of recent studies.marteilia spp. parasites are paramyxean organisms that affect several commercial species of molluscs, and thus have a socio-economical impact. these parasites also have an ecological impact on the biodiversity and population dynamics of natural mollusc beds. it has been over forty years since the first description of marteilia refringens, the first marteilia species described. despite four decades of research, the biology, cellular development, as well as the life cycle of marteilia parasites ar ...201526241745
detection of marteilia refringens infecting the european flat oyster ostrea edulis and the dwarf oyster ostrea stentina in southern portugal and spain.in the present study, marteilia sp. was detected by histological examination and in situ hybridisation in ostrea edulis and ostrea stentina collected in southern iberian peninsula. marteilia refringens dna was detected by pcr in o. edulis (collected in southern portugal) and o. stentina (collected in southern spain and portugal). sequencing analysis revealed the presence of m. refringens type o in o. edulis, and type o and m in o. stentina. this is the first confirmed detection of m. refringens ...201526149820
new data on perkinsus mediterraneus in the balearic archipelago: locations and affected species.perkinsus mediterraneus, a protozoan parasite that can cause perkinsosis (marine mollusc disease), was first detected in oysters ostrea edulis from mahon (minorca, balearic islands, spain) in 2004. several years later it was also found in andratx harbour (majorca, balearic islands) and in the gulf of manfredonia (adriatic coast of italy) in oyster populations. since 2007, perkinsus surveys have been conducted in different localities and shellfish species in the balearic archipelago. in the prese ...201425392044
marteiliosis in mussels: a rare disease?among 1280 cultured and wild adult mediterranean mussels, mytilus galloprovincialis, collected over a 1-year surveillance period from the slovene adriatic sea, 0.3% were histologically positive for the presence of marteilia spp. the infection was concentrated in winter. employing the molecular methods of pcr, cloning, dna restriction and sequencing, only marteilia refringens type m was detected in all the infected mussels. although all life-cycle stages of m. refringens severely infected digesti ...201424118033
contribution to the understanding of the cycle of the protozoan parasite marteilia refringens.the paramyxean parasite marteilia refringens infects several bivalve species including european flat oysters ostrea edulis and mediterranean mussels mytilus galloprovincialis. sequence polymorphism allowed definition of three parasite types 'm', 'o' and 'c' preferably detected in oysters, mussels and cockles respectively. transmission of the infection from infected bivalves to copepods paracartia grani could be experimentally achieved but assays from copepods to bivalves failed. in order to cont ...201424128728
a duplex quantitative real-time pcr assay for the detection of haplosporidium and perkinsus species in shellfish.a duplex quantitative real-time polymerase chain reaction (dq-pcr) assay was optimized to simultaneously detect haplosporidium spp. and perkinsus spp. of shellfish in one reaction. two sets of specific oligonucleotide primers for haplosporidium spp. and perkinsus spp., along with two hydrolysis probes specific for each parasite group, were used in the assay. the dq-pcr results were detected and analyzed using the light cycler 2.0 software system. the dq-pcr identified and differentiated the two ...201323371501
bonamia exitiosa (haplosporidia) observed infecting the european flat oyster ostrea edulis cultured on the spanish mediterranean coast.bonamia exitiosa and bonamia ostreae are parasites that reproduce within the haemocytes of several oyster species. in europe, the host species is the flat oyster ostrea edulis. the parasite b. ostreae has been responsible for mortalities since the late 1970s throughout the european atlantic coast. b. exitiosa was first detected, in 2007, on this continent in flat oysters cultured in galicia (nw spain). since then, the parasite has also been detected in france, italy and the united kingdom. the b ...201222465568
comparative experimental infection of the copepod paracartia grani with marteilia refringens and marteilia maurini.paracartia grani (copepoda) has been identified as a potential intermediate host in the life cycle of marteilia refringens, a paramyxean parasite infecting flat oysters. however, no intermediate host has yet been identified for marteilia maurini that infects mussels. a better understanding of the life cycle of these two marteilia types would clarify their taxonomic relationship and hypothesized co-specificity. for this purpose, experimental infections of copepods, p. grani, were performed using ...200818577099
identification of marteilia refringens infecting the razor clam solen marginatus by pcr and in situ hybridization.marteilia refringens is a protozoan parasite recognized as a significant pathogen of the european flat oyster ostrea edulis. it is believed to have a complex life-cycle involving several hosts. in this study, we applied molecular approaches to identify this parasite in samples of the razor clam solen marginatus from the south west coast of spain. we used a pcr assay to amplify a fragment of the igs rdna region. pcr products were sequenced and the phylogenetic affinity of the sequences was determ ...200818378424
in situ hybridization detection of initial infective stages of marteilia refringens (paramyxea) in its host mytilus galloprovincialis. 200818234023
dynamics of the parasite marteilia refringens (paramyxea) in mytilus galloprovincialis and zooplankton populations in alfacs bay (catalonia, spain).since the first description of marteilia refringens (paramyxea) in flat oysters ostrea edulis in 1968 in the aber wrach, brittany (france), the life-cycle of this parasite has remained unknown. however, recent studies, conducted in the 'claire' system, have proposed the planktonic copepod acartia grani as a potential intermediate host for the parasite. nevertheless, experimental transmission of the parasite through the copepod has failed. recent studies in this field have reported the presence o ...200717623489
protozoan parasites in cultured mussels mytilus galloprovincialis in the thermaikos gulf (north aegean sea, greece).the protozoans ancistrum mytili (oligohymenophorea: ancistridae) and marteilia refringens/maurini (marteiliidea: marteiliidae) were found parasitizing cultured mussels mytilus galloprovincialis l. in the thermaikos gulf (north aegean sea, greece). the former did not affect the condition index of infected mussels, in contrast to the latter, which did so and which also induced hemocyte infiltration in the affected digestive epithelium. the prevalence of both parasites was relatively high in a poll ...200616903237
validation of in situ hybridisation and histology assays for the detection of the oyster parasite marteilia refringens.an in situ hybridisation technique has been developed for the detection of infection in oysters with marteilia refringens with particular emphasis on light infections or confirmation of suspected cases by means of histology. although validation of new diagnostic methods is usually achieved by comparison with standard techniques, in our case the sensitivity and specificity of the standard (histology) had not previously been established. another point to consider is that surveillance and monitorin ...200516042038
polymorphisms in the sequences of marteilia internal transcribed spacer region of the ribosomal rna genes (its-1) in spain: genetic types are not related with bivalve hosts.marteilia refringens is a protozoan parasite causing a disease notifiable to the office international des epizooties (oie) and its distribution has implications for the transfer of live animals. the internal transcribed spacer-1 (its-1) from marteilia clones contains polymorphism. digestion with hhai reveals two different restriction profiles, previously referred as 'o' (marteilia from oyster or marteilia refringens) and 'm' (marteilia from mussels or marteilia maurini). the aim of the present w ...200515960656
infection dynamics of marteilia refringens in flat oyster ostrea edulis and copepod paracartia grani in a claire pond of marennes-oléron bay.the protozoan parasite marteilia refringens has been partly responsible for the severe decrease in the production of the european flat oyster ostrea edulis linnaeus in france since the 1970s. the calanoid copepod paracartia grani sars was recently found to be a host for m. refringens in french shallow-water oyster ponds ('claires'). this study reconsidered m. refringens transmission dynamics in the light of this finding, taking into account not only oyster infection dynamics and environmental fa ...200415584417
the molecular diagnosis of marteilia refringens and differentiation between marteilia strains infecting oysters and mussels based on the rdna igs sequence.marteilia refringens is a paramyxean parasite which infects the flat oyster ostrea edulis and mussels (mytilus galloprovincialis), where it has been attributed to a separate species, marteilia maurini, by several authors. doubts persist though as to the existence or not of two species of marteilia in europe. we have devised a molecular method for the diagnosis of m. refringens based on 358 bp nested-pcr of the rdna intergene spacer (rdna igs) which is capable of detecting 0.5 fg of m. refringens ...200415521629
specificity of pcr and in situ hybridization assays designed for detection of marteilia sydneyi and m. refringens.primers and dna probes designed for use in the specific detection of the paramyxean parasites marteilia sydneyi and marteilia refringens were tested for their potential to cross-react with closely related species in polymerase chain reaction (pcr) and in situ hybridization. pcr primers and a dna probe designed within the its1 rrna of m. sydneyi were specific for m. sydneyi when compared with related species of marteilia and marteilioides. pcr primers designed within the 18s rrna of m. refringens ...200212211606
needle in a haystack: involvement of the copepod paracartia grani in the life-cycle of the oyster pathogen marteilia refringens.marteilia refringens is a major pathogen of the european flat oyster, ostrea edulis linnaeus. since its description, the life-cycle of this protozoan parasite has eluded discovery. attempts to infect oysters experimentally have been unsuccessful and led to the hypothesis of a complex life-cycle involving several hosts. knowledge of this life-cycle is of central importance in order to manage oyster disease. however, the exploration of m. refringens life-cycle has been previously limited by the de ...200211922433
molecular evidence for the existence of two species of marteilia in europe.marteilia refringens is one of the most significant pathogens of bivalve molluscs. previous sequencing of the small subunit ribosomal rna gene of m. refringens isolates derived from the infected mussels (mytilus edulis and mytilus galloprovinciallis) and the oyster (ostrea edulis) in europe did not reveal genetic polymorphisms despite indications from epizootiological data that distinct types may exist. we investigated the existence of polymorphisms in the internal transcribed spacer region of t ...200111456321
first record of marteilia sp. in mussels mytilus galloprovincialis in croatia.marteiliosis is a disease of molluscs caused by marteilia refringens in europe and m. sydneyi in australia. during routine examination of cultured mussels mytilus galloprovinciallis in the northern adriatic, the occurrence of marteilia sp. was recorded with a prevalence of 5%. this parasite was not detected in flat oysters reared in the same area. the affiliation of the detected parasite in m. galloprovinciallis was confirmed by in situ hybridization using a m. refringens probe, specific at the ...200111324816
claire ponds as an experimental model for marteilia refringens life-cycle studies: new perspectives.since its first description, the paramyxean parasite marteilia refringens (grizel et al.) has been recognised as a significant pathogen of the european flat oyster ostrea edulis l. the existence of a complex life-cycle involving several hosts was postulated early on by many authors, although it remains unsolved. recent developments in the dna-based diagnosis of m. refringens provides new prospects for the detection of the parasite in potential hosts. however, this screening remains impeded by th ...200111165301
phylogenetic analysis of the small subunit ribosomal rna of marteilia refringens validates the existence of phylum paramyxea (desportes and perkins, 1990).marteilia refringens is recognized as one of the most significant pathogens of bivalve molluscs. the nucleotide sequence of the small subunit ribosomal rna gene of marteilia refringens is used to elucidate the phylogenetic position of the phylum paramyxea. genomic dna was extracted from sporangia of marteilia, purified from infected blue mussels, mytilus edulis, and flat oysters, ostrea edulis. the sequences obtained from marteilia species purified from both oysters and mussels were identical. t ...200010847346
seasonal variation and effects of age, food availability, size, gonadal development, and parasitism on the hemogram of mytilus galloprovincialisthe study of hemogram characteristics in a population of cultured mussels through a period of 18 months revealed that the concentration of circulating mytilus galloprovincialis hemocytes varied, following a seasonal pattern, being positively correlated with water temperature. most mussels had between 1 and 5 x 10(6) hemocytes/ml of hemolymph. differential counts showed that m. galloprovincialis hemolymph contained more granulocytes than hyalinocytes. the hemolymph cell concentration was not asso ...19989784355
southern hemisphere mollusc diseases and an overview of associated risk assessment problems.in australia and new zealand, bonamia sp. causes epizootics in flat oysters (tiostrea chilensis, ostrea angasi); marteilia sydneyi and mikrocytos roughleyi cause mortality in farmed rock oysters (saccostrea commercialis); and perkinsus olseni is pathogenic in abalone (haliotis spp.). marteilia lengehi, marteilioides branchialis, other marteilioides spp. and two species of haplosporidium are regarded as potential pathogens. a review of the pathogens causing diseases listed in the office internati ...19968890381
the effects of culture-site, depth, season, and stock source on the prevalence of marteilia refringens in cultured mussels (mytilus galloprovincialis lmk.) from galicia, spain.samples of a marteiliad parasite in mytilus galloprovincialis lmk. from nw spain were identified as marteilia refringens, using light and electron microscopy. the most important lesions in the mussel tissues were found in the digestive tubules at the moment of the release of the sporangia, resulting in a breakage of the epithelial cells of the digestive tubules. the plasmodia of a marteilia-like organism were also found in the gills, accompanied by a severe host reaction in 1 of the 4,200 examin ...19957776120
new evidence for the involvement of paracartia grani (copepoda, calanoida) in the life cycle of marteilia refringens (paramyxea).the dynamics of the protozoan parasite marteilia refringens was studied in thau lagoon, an important french shellfish site, for 1 year in three potential hosts: the mediterranean mussel mytilus galloprovincialis (mytiliidae), the grooved carpet shell ruditapes decussatus (veneriidae) and the copepod paracartia grani (acartiidae). parasite dna was detected by pcr in r. decussatus. in situ hybridisation showed necrotic cells of m. refringens in the digestive epithelia of some r. decussatus suggest ...201324080113
characterization of the protozoan parasite marteilia refringens infecting the dwarf oyster ostrea stentina in tunisia.marteilia refringens is a protozoan parasite recognized as a significant pathogen of the european flat oyster ostrea edulis. the life cycle of this species is still poorly known, although there is evidence of the need for intermediate host(s). in the present study, we have used molecular approaches to identify this parasite in samples of the dwarf oyster ostrea stentina after reports of massive mortality along the tunisian coasts. in 2009 we evaluated the status of o. stentina from monastir and ...201323219430
a marteilia-like parasite in blue mussels mytilus edulis in china.species of the genus marteilia (phylum paramyxea) are protozoan parasites of marine mollusks. marteilia spp. have been detected in mollusks from different parts of the world, but the presence of these parasites in china has not been previously reported. therefore, a survey was conducted to look for the presence of marteilia spp. in blue mussels mytilus edulis and asian green mussels perna viridis collected along china's coasts. histological and pcr analyses revealed that 5 of 180 m. edulis (prev ...201222897134
observation of a bonamia sp. infecting the oyster ostrea stentina in tunisia, and a consideration of its phylogenetic affinities.the small non-commercial oyster ostrea stentina co-occurs with commercially important ostrea edulis in the mediterranean sea, yet its disposition with respect to the destructive pathogens bonamia ostreae and marteilia refringens is unknown. we began an evaluation of the bonamia spp. infection status of o. stentina from hammamet, tunisia, in june 2007 using polymerase chain reaction diagnostics followed by histology and in situ hybridization. of 85 o. stentina sampled, nine were pcr-positive for ...201020036670
detection of marteilia refringens using nested pcr and in situ hybridisation in chamelea gallina from the balearic islands (spain).in the course of a histopathological survey performed to discover the cause of mass mortality of the striped clam chamelea gallina in the balearic islands (spain, mediterranean sea), we detected a marteilia-like parasite in 3 clams. molecular methods were applied to identify the parasite. dna extracted from a paraffin block was used to carry out a pcr assay for marteilia refringens detection based on a rdna sequence of the parasite (the intergenic spacer of ribosomal genes, igs). the nucleotide ...200819062756
dna probes as potential tools for the detection of marteilia refringens.since its first description, the paramyxean parasite marteilia refringens has been recognized as a significant pathogen of bivalve mollusks. the existence of a complex life cycle was postulated by many authors. here we report the development of dna-based detection assays as powerful tools to elucidate the marteilia refringens life cycle. after alignment of the marteilia refringens ribosomal dna small subunit sequence with those of various eukaryotic organisms, polymerase chain reaction primers w ...199910612684
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