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Full-Text Articles in Life Sciences
Epizootiology Of The Parasitic Dinoflagellate Hematodinium Sp In The American Blue Crab Callinectes Sapidus, Ga Messick, Jeffrey D. Shields
Epizootiology Of The Parasitic Dinoflagellate Hematodinium Sp In The American Blue Crab Callinectes Sapidus, Ga Messick, Jeffrey D. Shields
VIMS Articles
Hematodinium sp. is a parasitic dinoflagellate that infects and kills blue crabs Callinectes sapidus. Periodic outbreaks of dinoflagellate infections with subsequent high host mortalities prompted a study of the epizootiology and distribution of the crab pathogen. Hemolymph samples from over 13 000 crabs were assessed for infections over 8 yr. Moderate to high prevalences were found at several locations along the Atlantic and Gulf coasts of the United States. In the coastal bays of Maryland and Virginia, prevalence followed a seasonal pattern, with a sharp peak in late autumn. Infections were significantly more prevalent in crabs measuring less than 30 …
Seasonal Variations Of Size-Fractionated Phytoplankton Along The Salinity Gradient In The York River Estuary, Virginia (Usa), Y Sin, Rl Wetzel, I. C. Anderson
Seasonal Variations Of Size-Fractionated Phytoplankton Along The Salinity Gradient In The York River Estuary, Virginia (Usa), Y Sin, Rl Wetzel, I. C. Anderson
VIMS Articles
The dynamics of phytoplankton size structure were investigated in the freshwater, transitional and estuarine zones of the York River over an annual cycle. The contribution of large cells (microplankton, >20 mu m) to total concentrations of chlorophyll a increased downstream during winter, whereas that of small cells (nanoplankton, 3-20 mu m; picoplankton,m) increased downstream during summer. In the freshwater region, the contribution of micro phytoplankton to total concentrations of chlorophyll a was significant during warm seasons (spring and summer) but not during colder seasons (winter), whereas the contribution of small-sized cells (especially picoplankton) increased during cold seasons. Temperature, light and …
Haplosporidiosis In The Pacific Oyster Crassostrea Gigas From The French Atlantic Coast, R Renault, Na Stokes, Et Al, Em Burreson
Haplosporidiosis In The Pacific Oyster Crassostrea Gigas From The French Atlantic Coast, R Renault, Na Stokes, Et Al, Em Burreson
VIMS Articles
Two cases of haplosporidian infection occurred during 1993 in Pacific oysters Crassostrea gigas from the French Atlantic coast. The localization and ultrastructure of the plasmodia are described. In situ hybridization of infected tissue sections was conducted with DNA probes for oyster-infecting haplosporidians. The Haplosporidium nelsoni-specific DNA probe MSX1347 hybridized with the C. gigas parasite, and the H, costale-specific probe SSO1318 did not hybridize. Total genomic DNA was extracted from the infected tissue sections for polymerase chain reaction (PCR) amplification of the haplosporidian. PCR amplifications with H. nelsoni-specific primers and with 'universal' actin primers did not yield the expected products of …
Actin Gene Family Evolution And The Phylogeny Of Coleoid Cephalopods (Mollusca: Cephalopoda), David B. Carlini, Kimberly S. Reece, John Graves
Actin Gene Family Evolution And The Phylogeny Of Coleoid Cephalopods (Mollusca: Cephalopoda), David B. Carlini, Kimberly S. Reece, John Graves
VIMS Articles
Phylogenetic analysis conducted on a 784-bp fragment of 82 actin gene sequences of 44 coleoid cephalopod taxa, along with results obtained from genomic Southern blot analysis, confirmed the presence of at least three distinct actin loci in coleoids. Actin isoforms were characteri zed through phylogenetic analysis of representative cephalopod sequences from each of the three isoforms, along with translated actin cDNA sequences from a diverse array of metazoan taxa downloaded from GenBank. One of the three isoforms found in cephalopods was closely related to actin sequences expressed in the muscular tissues of other molluscs. A second isoform was most similar …
Zoosporulation Of A New Perkinsus Species Isolated From The Gills Of The Softshell Clam Mya Arenaria, Sm Mclaughlin, Bd Tall, A Shaheen, Ee Elsayed, M Faisal
Zoosporulation Of A New Perkinsus Species Isolated From The Gills Of The Softshell Clam Mya Arenaria, Sm Mclaughlin, Bd Tall, A Shaheen, Ee Elsayed, M Faisal
VIMS Articles
A gill-associated Perkinsus sp. isolated from the softshell clam (Myo arenaria) is described as a new species, P. chesapeaki sp. nov. Examination of the parasite in seawater cultures revealed life cycle stages and zoosporulation processes similar to those described for other species of the genus Perkinsus. Prezoosporangia developed thickened cell walls upon contraction of the cytoplasm and development of a distinctive clear area between the cell wall and the protoplast. Successive bipartition of the protoplast led to the formation of hundred's of zoospores within mature sporangia. Zoospores were released into seawater through one or more discharge tubes, Ultrastructural studies revealed …
'Candidatus Xenohaliotis Californiensis', A Newly Described Pathogen Of Abalone, Haliotis Spp., Along The West Coast Of North America, Cs Friedman, Kb Andree, Ka Beauchamp, Jd Moore, Tt Robbins, Jeffrey D. Shields, Rp Hendricks
'Candidatus Xenohaliotis Californiensis', A Newly Described Pathogen Of Abalone, Haliotis Spp., Along The West Coast Of North America, Cs Friedman, Kb Andree, Ka Beauchamp, Jd Moore, Tt Robbins, Jeffrey D. Shields, Rp Hendricks
VIMS Articles
Withering syndrome is a fatal disease of wild and cultured abalone. Haliotis spp., that inhabit the west coast of North America. The aetiological agent of withering syndrome has recently been identified as a member of the family Rickettsiaceae in the order Rickettsiales. Using a combination of morphological, serological, life history and genomic (16S rDNA) characterization. we have identified this bacterium as a unique taxon and propose the provisional status of 'Candidatus Xenohaliotis californiensis', The Gram-negative. obligate intracellular pleomorphic bacterium is found within membrane-bound vacuoles in the cytoplasm of abalone gastrointestinal epithelial cells. The bacterium is not cultivable on synthetic media …
Strategies For Assessing The Implications Of Malformed Frogs For Environmental Health, Jg Burkhart, Robert C. Hale
Strategies For Assessing The Implications Of Malformed Frogs For Environmental Health, Jg Burkhart, Robert C. Hale
VIMS Articles
The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state …
Progression Of Diseases Caused By The Oyster Parasites, Perkinsus Marinus And Haplosporidium Nelsoni, In Crassostrea Virginica On Constructed Intertidal Reefs, Aswani Volety, Frank O. Perkins, Roger Mann, Pr Hershberg
Progression Of Diseases Caused By The Oyster Parasites, Perkinsus Marinus And Haplosporidium Nelsoni, In Crassostrea Virginica On Constructed Intertidal Reefs, Aswani Volety, Frank O. Perkins, Roger Mann, Pr Hershberg
VIMS Articles
The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium nelsoni were evaluated by periodic sampling (May 1994-December 1995) of eastern oysters Crassostrea virginica on an artificial reef located in the Piankatank River, Virginia. The infections observed were recorded as a function of: (1) prevalence and intensity; (2) oyster size and age; and (3) depth below mean low water at which the host oyster was found on the reef. Only a very small number of oysters were infected with the two species of pathogens on the oyster reef during the first 11 months of Life. In the …
Prevalence Of Perkinsus Spp. In Chesapeake Bay Soft-Shell Clams, Mya Arenaria Linnaeus, 1758 During 1990-1998, Sm Mclaughlin, M Faisal
Prevalence Of Perkinsus Spp. In Chesapeake Bay Soft-Shell Clams, Mya Arenaria Linnaeus, 1758 During 1990-1998, Sm Mclaughlin, M Faisal
VIMS Articles
Prevalence and intensity of Perkinsus spp. infections were determined in soft-shell clams Mya arenaria during 1990 to 1998 based upon incubation of rectal tissues in Ray's fluid thioglycollate medium. During the study, soft-shell clams were collected from 18 sites in the upper Chesapeake Bay in Maryland. Enlarged hypnospores were found in similar to 7% (114/1,705) of the soft-shell clams. Peak prevalences occurred in the fail of 1992 with similar to 53% (16/30) at Piney Point and 50% (15/30) at Eastern Neck, and in August 1995 with similar to 64%(18/28) and similar to 37% (11/30) at Cedar Point and Piney Point, …