Gill epithelial cell nuclear virus disease is prevalent and widespread in Mya arenaria clams of Chesapeake Bay, USA.

Several historic investigations have reported intranuclear virus infections of Mya arenaria soft-shell clams from the Atlantic coast of North America, but their descriptive details are limited. Among numerous multi-clam samples of Chesapeake Bay M. arenaria that were analyzed histopathologically during clam population surveys from 2000-2009, virus replication apparently caused extreme hypertrophy among the infected nuclei of gill epithelial cells.

Immunoassays and diagnostic antibodies for Perkinsus spp. pathogens of marine molluscs.

Perkinsus sp. protozoans are parasites of a wide variety of molluscs around the world and are responsible for episodes of mass mortalities and large economic losses for aquaculture industries and fisheries. The first step towards the management of infectious episodes is the reliable detection of Perkinsus species.

A Paraffin Microtomy Method for Improved and Efficient Production of Standardized Plastic Microfibers.

Microfibers are one of the most abundant microplastic particle types found in the environment, where they cause negative impacts on organisms and possibly on human health. Microfibers should be included in a wide range of laboratory studies; however, microfibers for scientific studies are not commercially available. Current methods to make microfibers generally create particles with large size ranges and poor precision, and efficient production of particles ≤100 µm is difficult.

Parasites in two coexisting bivalves of the Patagonia coast, southwestern Atlantic Ocean: The Puelche oyster (Ostrea puelchana) and false oyster (Pododesmus rudis).

The purpose of this study was to compare the parasites of two coexisting bivalves, the edible Puelche oyster (Ostrea puelchana) and the false oyster (Pododesmus rudis) that lives attached to O. puelchana shells, and to investigate their host specificity. Samples from wild populations, 465 O.

A novel monoclonal Perkinsus chesapeaki in vitro isolate from an Australian cockle, Anadara trapezia.

A monoclonal Perkinsus chesapeaki isolate was established from 1 of 10 infected Australian Anadara trapezia cockles. Morphological features were similar to those of described P. chesapeaki isolates, and also included a unique vermiform schizont cell-type.

Development and applications of Ray's fluid thioglycollate media for detection and manipulation of Perkinsus spp. pathogens of marine molluscs.

During the early 1950s, Sammy M. Ray discovered that his high-salt modification of fluid thioglycollate sterility test medium caused dramatic in vitro enlargement of Perkinsus marinus (=Dermocystidium marinum) cells that coincidentally infected several experimentally cultured oyster gill tissue explants. Subsequent testing confirmed that the enlarged cells among some oyster tissues incubated in Ray's fluid thioglycollate medium (RFTM) were those of that newly described oyster pathogen.

Perkinsus sp. infections and in vitro isolates from Anadara trapezia (mud arks) of Queensland, Australia.

Perkinsus sp. protists were found infecting Anadara trapezia mud ark cockles at 6 sites in Moreton Bay, Queensland, Australia, at prevalences of 4 to 100% during 2011 as determined by surveys using Ray's fluid thioglycollate medium. Perkinsus sp.

Two Perkinsus spp. infect Crassostrea gasar oysters from cultured and wild populations of the Rio São Francisco estuary, Sergipe, northeastern Brazil.

Brazilian production of bivalve molluscs is small but expanding, especially in the northeastern region where the native oysters Crassostrea rhizophorae and C. gasar are abundant, and tropical weather promotes their rapid growth. Studies on bivalve pathology are scarce in Brazil, with only a few employing techniques for detecting protozoan pathogens listed by the World Organisation for Animal Health (OIE).

Signal recognition particle RNA in dinoflagellates and the Perkinsid Perkinsus marinus.

In dinoflagellates and perkinsids, the molecular structure of the protein translocating machinery is unclear. Here, we identified several types of full-length signal recognition particle (SRP) RNA genes from Karenia brevis (dinoflagellate) and Perkinsus marinus (perkinsid). We also identified the four SRP S-domain proteins, but not the two Alu domain proteins, from P.

Diseases of oysters Crassostrea ariakensis and C. virginica reared in ambient waters from the Choptank River, Maryland and the Indian River Lagoon, Florida.

To assess potential benefits and liabilities from a proposed introduction of Asian Suminoe oysters, susceptibilities of exotic Crassostrea ariakensis and native C. virginica oysters were compared during exposures to pathogens endemic in temperate, mesohaline waters of Chesapeake Bay and sub-tropical, polyhaline Atlantic waters of southern Florida, USA. Cohorts of diploid, sibling oysters of both species were periodically tested for diseases while reared in mesocosms receiving ambient waters from the Choptank River, Maryland (>3 yr) or the Indian River Lagoon, Florida (10 to 11 mo).

Spliced leader RNAs, mitochondrial gene frameshifts and multi-protein phylogeny expand support for the genus Perkinsus as a unique group of alveolates.

The genus Perkinsus occupies a precarious phylogenetic position. To gain a better understanding of the relationship between perkinsids, dinoflagellates and other alveolates, we analyzed the nuclear-encoded spliced-leader (SL) RNA and mitochondrial genes, intron prevalence, and multi-protein phylogenies. In contrast to the canonical 22-nt SL found in dinoflagellates (DinoSL), P.

Introns, alternative splicing, spliced leader trans-splicing and differential expression of pcna and cyclin in Perkinsus marinus.

To gain understanding on the structure and regulation of growth-related genes of the parasitic alveolatePerkinsus marinus, we analyzed genes encoding proliferating cell nuclear antigen (pcna) and cyclins (cyclin). Comparison of the full-length cDNAs with the corresponding genomic sequences revealedtrans-splicing of the mRNAs of these genes with a conserved 21-22 nt spliced leader. Over 10 copies ofpcnawere detected, with identical gene structures and similar nucleotide (nt) sequences (88-99%), encoding largely identical amino acid sequences (aa).

Exotic Perkinsus sp. protozoa in an imported Vietnamese ornamental clam (Tridacna crocea) maintained in a home aquarium.

An adult, hermaphroditic Tridacna crocea ornamental clam imported from Vietnam into the USA became terminally moribund with sloughed byssal tissue and incomplete extension of the poorly responsive mantle and was necropsied. Necropsy findings included emaciation, visceral mass edema, and rare multifocal, 1-mm diameter, off-white to light tan gill nodules. Histopathology revealed marked inflammation and necrosis within the visceral mass and gills, with interstitial edema and atrophy of glandular, gonadal, and muscular tissues.

Molecular epizootiology of Perkinsus marinus and P. chesapeaki infections among wild oysters and clams in Chesapeake Bay, USA.

Perkinsus marinus and P. chesapeaki host ranges among wild Chesapeake Bay, USA, region bivalves were examined by surveying Crassostrea virginica oysters and members of several sympatric clam species from 11 locations. Perkinsus genus- and species-specific PCR assays were performed on DNA samples from 731 molluscs, and species-specific in situ hybridization assays were performed on a selected subset of histological samples whose PCR results indicated dual or atypical Perkinsus sp.

Numerical quantification of Perkinsus marinus in the American oyster Crassostrea virginica (Gmelin, 1791) (Mollusca: Bivalvia) by modern stereology.

Species of Perkinsus are responsible for high mortalities of bivalve molluscs world-wide. Techniques to accurately estimate parasites in tissues are required to improve understanding of perkinsosis. This study quantifies the number and tissue distribution of Perkinsus marinus in Crassostrea virginica by modern stereology and immunohistochemistry.

Description of Perkinsus beihaiensis n. sp., a new Perkinsus sp. parasite in oysters of Southern China.

Oysters were collected from coastal locations in China from 1999-2006 for parasite analyses by molecular, culture, and histological techniques. Polymerase chain reaction-based assays targeting the internal transcribed spacer (ITS) region of the ribosomal RNA gene complex were performed to detect the presence of Perkinsus species. Sequencing and phylogenetic analysis of amplified Perkinsus sp.

Experimental cross-infections by Perkinsus marinus and P. chesapeaki in three sympatric species of Chesapeake Bay oysters and clams.

In controlled laboratory transmission experiments, uniform doses of axenic in vitro isolate cultures of Perkinsus marinus from a Crassostrea virginica oyster, and of independent P. chesapeaki isolates from Chesapeake Bay Mya arenaria and Macoma balthica clams, were used to reciprocally challenge Perkinsus sp.-free C.

Perkinsus olseni in vitro isolates from the New Zealand clam Austrovenus stutchburyi.

Perkinsus olseni infections are reported at 10%-84% prevalences among Austrovenus stutchburyi clams (cockles) in northern New Zealand coastal waters. However, P. olseni has not yet been propagated in vitro from New Zealand clams.

Development of a real time quantitative PCR assay for the hard clam pathogen Quahog Parasite Unknown (QPX).

Quahog Parasite Unknown (QPX) is a thraustochytrid pathogen responsible for catastrophic mortalities of the northern quahog (hard clam) Mercenaria mercenaria. A real-time quantitative polymerase chain reaction (qPCR) assay was developed to assist research efforts on QPX ecology and pathology. Sensitivity of the assay was evaluated with serial dilutions of QPX-cultured cells to determine the lowest concentration of DNA that remained detectable in both the presence and absence of extraneous environmental substances.

In vitro propagation of two Perkinsus spp. parasites from Japanese Manila clams Venerupis philippinarum and description of Perkinsus honshuensis n. sp.

Perkinsus species are destructive parasites of commercial Manila clams, Venerupis philippinarum, in Japan, Korea, and Spain. However, in vitro parasite cultures from this important host clam are not available. Tissues of Manila clams collected during April 2002 in Gokasho Bay, Japan harbored Perkinsus sp.

Molecular, morphological, and experimental evidence support the synonymy of Perkinsus chesapeaki and Perkinsus andrewsi.

Diverse analytical and experimental results confirm that two protistan parasites, Perkinsus chesapeaki and Perkinsus andrewsi, described separately as parasites of Mya arenaria and Macoma balthica clams sympatric in Chesapeake Bay, USA, represent a single species. Ribosomal RNA (rRNA) internal transcribed spacer (ITS) regions, rRNA large subunit (LSU) gene, and actin gene sequences were obtained from clonal Perkinsus spp. cultured in vitro.

Systematic evaluation of factors controlling Perkinsus marinus transmission dynamics in lower Chesapeake Bay.

The transmission of Perkinsus marinus in eastern oysters Crassostrea virginica in relation to water temperature, host oyster mortality, and water-column abundance of anti-P. marinus antibody-labeled cells was systematically examined for 20 mo at a site in the lower York River, Virginia, USA. Uninfected sentinel oysters were naturally exposed to the parasite at 2 wk intervals throughout the course of the study to determine the periodicity and rates of parasite transmission.

Two epizootic diseases in Chesapeake Bay commercial clams, Mya arenaria and Tagelus plebeius.

Declining Chesapeake Bay harvests of softshell clams, together with historical and emerging reports of epizootic diseases in Mya arenaria, prompted a survey in summer 2000 of the health status of selected commercial clam populations. All sampled populations (8 M arenaria softshell clam, 2 Tagelus plebeius razor clam) were infected by Perkinsus sp. protozoans at prevalences ranging from 30 to 100% of sampled clams.

Serological affinities of the oyster pathogen Perkinsus marinus (Apicomplexa) with some dinoflagellates (Dinophyceae).

The protozoan oyster pathogen Perkinsus marinus is classified in the phylum Apicomplexa, although molecular-genetic and ultrastructural evidence increasingly concur on its closer phylogenetic relationship with the dinoflagellates. To test for evidence of serological epitopes common to P. marinus and dinoflagellates, we probed 19 free-living and 8 parasitic dinoflagellate, or dinoflagellate-like, species for cross-reactivity with polyclonal antibodies to P.