| variation in enzyme activities of the american oyster (crassostrea virginica) relative to size and season. | | 1975 | 166789 |
| comparative study of methods for the enumeration of total and fecal coliforms in the eastern oyster, crassostrea virginica. | violet red bile agar and coli-count sampler (millipore corp.) procedures were shown to be acceptable alternatives to the standard most-probable-number method for monitoring relative coliform levels in oysters. | 1978 | 367271 |
| vivo clearance of enteric bacteria from the hemolymph of the hard clam and the american oyster. | american oysters, crassostrea virginica, and hard clams, mercenaria mercenaria, were experimentally contaminated with escherichia coli, salmonella typhimurium, and shigella flexneri either by intracardial injection or via the natural route of ingestion. bacterial inactivation in the hemolymph was monitored for 72 h after exposure to these enteric pathogens at 20 and 6 degrees c. at 6 degrees c, both mean bacterial uptake by ingestion and subsequent clearance was singificantly lower that at 20 de ... | 1979 | 378127 |
| toxicity of aroclor-r 1254 and its physiological activity in several estuarine organisms. | the occurrence of high concentrations of a pcb (aroclor 1254) in the pensacola estuary prompted field and laboratory studies by the gulf breeze environmental research laboratory (epa). monitoring of the estuary indicates the chemical is present in all components--particularly in sediments and fishes. residues appear to be diminishing in sediments. toxicity tests show estuarine species sensitive at ppb concentrations in water, with a ciliate protozoan (tetrahymena pyriformis w), (fundulus similis ... | 1975 | 805570 |
| distribution of glycogen resulting from degradation of 14c-labelled bacteria in the american oyster, crassostrea virginica. | | 1976 | 815442 |
| heptachlor: toxicity to and uptake by several estuarine organisms. | technical-grade heptachlor (65% heptachlor, 22% trans-chlordane, 2% cis-chlordane, and 2% nonachlor) was tested in 96-hr bioassays to determine its toxicity to estuarine animals. the test organisms and the 96-hr lc50 or ec50s based on measured concentrations in water) are as follows: american oyster (crassostrea virginica), 1.5 mug/liter; pink shrimp (penaeus duorarum), 0.11 mug/liter; grass shrimp (palaemonetes vulgaris), 1.06 mug/liter; sheepshead minnow (cyprinodon variegatus), 3.68 mug/liter ... | 1976 | 966323 |
| role of bacteria in bioaccumulation of mercury in the oyster crassostrea virginica. | an investigation of mercury-resistant bacteria was undertaken to determine their role in the accumulation of mercury in a simplified food chain. oysters (crassostrea virginica) were maintained in a closed system, sealed aquarium with stirred, aerated water containing 10 mug of 203-hgcl2 per liter. uptake of 203-hg by oysters held under control conditions was compared with that of 203-hg uptake by oysters under similar conditions except that mercury-accumulating and mercury-metabolizing species o ... | 1975 | 1147622 |
| chemotactic attraction of crassostrea virginica hemolymph cells to staphylococcus lactus. | | 1976 | 1245744 |
| persistence of vibrio vulnificus in tissues of gulf coast oysters, crassostrea virginica, exposed to seawater disinfected with uv light. | vibrio vulnificus is an estuarine bacterium which can cause opportunistic infections in humans consuming raw gulf coast oysters, crassostrea virginica. although v. vulnificus is known as a ubiquitous organism in the gulf of mexico, its ecological relationship with c. virginica has not been adequately defined. the objective of the present study was to test the hypothesis that v. vulnificus is a persistent microbial flora of oysters and unamenable to traditional methods of controlled purification, ... | 1992 | 1622218 |
| evidence for regular sporulation by haplosporidium nelsoni (msx) (ascetospora; haplosporidiidae) in spat of the american oyster, crassostrea virginica. | the spore stage of haplosporidium nelsoni, the ascetosporan parasite causing multinucleated sphere unknown (msx) disease in oysters, crassostrea virginica, has been reported so rarely (less than 0.01% of infected oysters) that a second host has been postulated. however, recent intensive sampling of young (less than 1 year) oysters in delaware bay, u.s. suggests that spore formation occurs regularly in this group and that spores are produced in at least 75-85% of all infections reaching the advan ... | 1991 | 1787418 |
| lectin binding characteristics of haemocytes and parasites in the oyster, crassostrea virginica, infected with haplosporidium nelsoni (msx). | lectin-binding surface receptors on haemocytes from host oysters were compared with those on plasmodial stages of the ascetosporan parasite haplosporidium nelsoni (msx). haemocytes were agglutinated, in descending order of strength, by wga, hpa, lpa, cona, and cfa. gma, pha, and rma lectins failed to agglutinate at 100 micrograms/ml, the highest concentration tested. these results indicate that haemocytes contain surface receptors resembling n-acetyl-d-glucosamine and alpha-methylmannopyranoside ... | 1990 | 1964721 |
| a genetic discontinuity in a continuously distributed species: mitochondrial dna in the american oyster, crassostrea virginica. | restriction site variation in mitochondrial dna (mtdna) of the american oyster (crassostrea virginica) was surveyed in continuously distributed populations sampled from the gulf of st. lawrence, canada, to brownsville, texas. mtdna clonal diversity was high, with 82 different haplotypes revealed among 212 oysters with 13 endonucleases. the mtdna clones grouped into two distinct genetic arrays (estimated to differ by about 2.6% in nucleotide sequence) that characterized oysters collected north vs ... | 1990 | 1968412 |
| trace and heavy metals in the oyster crassostrea virginica, san andres lagoon, tamaulipas, mexico. | | 1990 | 2279142 |
| occurrence and characteristics of agglutination of vibrio cholerae by serum from the eastern oyster, crassostrea virginica. | cell-free hemolymph (serum) of the eastern oyster, crassostrea virginica, agglutinated vibrio cholerae, including all o1 serovars and biovars. seventy-nine other strains of bacteria, including 14 genera and 26 species, were not agglutinated. the a, b, and c factors of o1 antigen were not involved in agglutination. bacterial agglutinating (ba) activity was demonstrated for oysters inhabiting different environments of the u.s. atlantic and gulf coasts. oyster serum ba titers showed high individual ... | 1989 | 2483041 |
| a method for the enumeration of poliovirus in selected molluscan shellfish. | a virus extraction procedure was developed and evaluated on five commercially important molluscan shellfish species: crassostrea virginica (eastern oyster), mya arenaria (softshell clam), mytilus edulis (blue mussel), mercenaria mercenaria (hardshell clam), and crassostrea gigas, (pacific oyster). shellfish tissue homogenates were spiked with poliovirus, extracted, and plaque assayed. mean virus recoveries were: c. virginica, 63.8%; m. arenaria, 42.1%; m. edulis, 67.3%; m. mercenaria, 48.3%; and ... | 1989 | 2559103 |
| survival of vibrio vulnificus in shellstock and shucked oysters (crassostrea gigas and crassostrea virginica) and effects of isolation medium on recovery. | when two species of shellstock oysters were artificially contaminated with vibrio vulnificus, the bacterium survived when the oysters were stored at 10 degrees c and below. large numbers of endogenous v. vulnificus cells were found after 7 days at both 0.5 and 10 degrees c in uninoculated control oysters (crassostrea virginica). oysters allowed to take up v. vulnificus from seawater retained the bacterium for 14 days at 2 degrees c. the presence of v. vulnificus in the drip exuded from the shell ... | 1989 | 2619304 |
| comparison of hemolymph proteins from resistant and susceptible oysters, crassostrea virginica, exposed to the parasite haplosporidium nelsoni (msx). | | 1986 | 3084662 |
| infection and mortality patterns in strains of oysters crassostrea virginica selected for resistance to the parasite haplosporidium nelsoni (msx). | strains of oysters crassostrea virginica resistant to mortality caused by the parasite haplosporidium nelsoni (msx) were developed and tested through 6 generations. in addition, strains in each generation were followed for up to 6 yr of continuous exposure to the parasite in nature. selected strains responded to challenge by the parasite with gradually improved survival in successive generations. they were slower to develop patent infections than were unselected groups and were able to delay mor ... | 1987 | 3108479 |
| nutritional availability to rats of selenium in four seafoods: crab (callinectes sapidus), oyster (crassostrea virginica), shrimp (penaeus duorarum) and baltic herring (clupea harengus). | 1. the present study was conducted to determine the biological availability to rats of the selenium in four high-se seafoods: crab (callinectes sapidus), oyster (crassostrea virginica), shrimp (penaeus duorarum) and baltic herring (clupea harengus). 2. weanling male rats were fed on a se-deficient torula yeast diet for 4 weeks followed by either continued depletion or repletion for 4 weeks with 0.05, 0.1 or 0.2 microgram se as selenite/g, or 0.1 or 0.2 microgram se as freeze-dried cooked test fo ... | 1986 | 3676154 |
| morphological and biochemical properties of four members of a novel group of reoviruses isolated from aquatic animals. | the morphological, biochemical and growth characteristics of four members of the reoviridae, three from the fish hosts, golden shiner (notemigonus crysoleucas), chum salmon (oncorhynchus keta) and channel catfish (ictalurus punctatus) and one from american oyster (crassostrea virginica), were compared. electron microscopy of negatively stained virions revealed icosahedral particles approximately 75 nm in diameter composed of a double capsid. complete particles had buoyant densities in cscl of 1. ... | 1987 | 3819694 |
| uptake and clearance of vibrio vulnificus from gulf coast oysters (crassostrea virginica). | oysters collected in late winter, when they were free of vibrio vulnificus, were exposed in the organism in the laboratory. the oysters effectively concentrated the bacteria from seawater, but when the inoculum was removed, the bacteria were rapidly cleared from the oyster tissues. these results suggest that v. vulnificus may be found in oysters as a result of filtration of the bacteria from seawater rather than active multiplication of the bacteria in the oysters. | 1985 | 4091570 |
| single and continuous exposure of the adult american oyster, crassostrea virginica, to marine vibrios. | | 1974 | 4597645 |
| the carbohydrate composition of invertebrate hemagglutinin subunits isolated from the lobster panulirus argus and the oyster crassostrea virginica. | | 1973 | 4683998 |
| gamete cross incompatibility and inbreeding in the commercial american oyster, crassostrea virginica gmelin. | | 1973 | 4764764 |
| the effect of temperature on cellular reactions of crassostrea virginica to the injection of avian erythrocytes. | | 1974 | 4819579 |
| light and electron microscopy of the leucocytes of crassostrea virginica (mollusca: pelecypoda). | | 1971 | 5110852 |
| clostridium botulinum in marine sediments and in the oyster (crassostrea virginica) from mobile bay. | | 1967 | 5342368 |
| bacteriological study of laboratory-reared juvenile american oysters (crassostrea virginica). | | 1969 | 5371083 |
| immunological capabilities of the oyster crassostrea virginica. | | 1969 | 5795812 |
| perivascular leucocytosis and other types of cellular reactions in the oyster crassostrea virginica experimentally infected with the nematode angiostrongylus cantonensis. | | 1966 | 5905537 |
| hemagglutinin in the blood of the oyster crassostrea virginica. | | 1966 | 5980200 |
| inefficient accumulation of low levels of monodispersed and feces-associated poliovirus in oysters. | the accumulation of low levels (0.002 to 0.18 pfu/ml) of both feces-associated and monodispersed poliovirus by oysters (crassostrea virginica or c. gigas) and clams (mercenaria mercenaria) was investigated. these levels were chosen to duplicate the conditions present in light to moderately polluted waters. experiments were performed in both small- and large-scale flowing seawater systems, developed to mimic the natural marine habitats of shellfish. under these experimental conditions, viral accu ... | 1982 | 6297388 |
| accumulation of sediment-associated viruses in shellfish. | the present study focused on the importance of contaminated sediments in shellfish accumulation of human viruses. epifaunal (crassostrea virginica) and infaunal (mercenaria mercenaria) shellfish, placed on or in cores, were exposed to either resuspended or undisturbed sediments containing bound poliovirus type 1 (lsc 2ab). consistent bioaccumulation by oysters (four of five trials) was only noted when sediment-bound viruses occurred in the water column. virus accumulation was observed in a singl ... | 1983 | 6297392 |
| a lectin on the hemocyte membrane of the oyster (crassostrea virginica). | using antisera produced against a serum lectin we have shown by employing immunocytofluorescence that hemocytes from the oyster, crassostrea virginica, possess a lectin which is situated on the external surface of the cell membrane. the antisera block the binding of hemocyte microsomes to protease-treated vertebrate erythrocytes, thus confirming that the hemocyte membrane lectin is serologically related to the serum lectin. the major serum lectin has an apparent mass of 34,000. flow cytometry ha ... | 1984 | 6435887 |
| trace metal residues in shellfish from maryland waters, 1976-1980. | levels of seven heavy metal residues, arsenic, cadmium, chromium, copper, lead, mercury and zinc were monitored in samples of the american oyster (crassostrea virginica), the soft shell clam (mya arenaria), the hard shell clam (mercinaria mercinaria) and the blue crab (callinectes sapidus). samples were taken from the maryland section of the chesapeake bay and its tributaries over a five year period (1976-80). this study was undertaken to provide an estimate of a baseline for values of trace hea ... | 1984 | 6501792 |
| absorption and distribution of cadmium in mice fed diets containing either inorganic or oyster-incorporated cadmium. | to determine the absorption, organ distribution, and retention of organically bound cadmium (cd) and the effects of dietary zinc (zn) on cd metabolism, groups of mice were fed five different diets. the organic cd used in the diets was in the form of lyophilized oyster (crassostrea virginica) that had accumulated radiolabeled 109cd through a plankton food chain. the mice were fed either a standard basal mouse diet (ain-76) or diets containing five or eight times the zn concentration of the basal ... | 1984 | 6695373 |
| effects of storage on microbial loads of two commercially important shellfish species, crassostrea virginica and mercenaria campechiensis. | the effects of storage on the microbial load in two commercially important species of shellfish were examined. oysters (crassostrea virginica) were stored as shellstock, shucked meats, and fully processed meats at four temperatures for up to 21 days, and clams (mercenaria campechiensis) were stored only as shellstock. the concentrations of most microbiological groups of organisms increased with the duration and temperature of storage in both shellfish species, although the increases were signifi ... | 1983 | 6859844 |
| the intracellular partitioning of trace metals in marine shellfish. | marine organisms have evolved a number of metabolic strategies to deal with potentially toxic trace metals. to determine how "detoxification" mechanisms such as metal-binding proteins and concretions are involved in the intracellular partitioning of trace metals in marine shellfish, the oyster, crassostrea virginica, and the blue crab, callincetes sapidus, were exposed to controlled levels of trace metals. oysters accumulated cadmium readily and produced specific low molecular weight, cadmium-bi ... | 1983 | 6879150 |
| studies of cystic fibrosis utilizing mucociliary activity in oyster gills. | crassostrea virginica, the oyster native to the gulf coast, has served as a source of ciliated epithelium for studies on the inhibitory factor in cystic fibrosis. in these studies, protein molecules with biological activity, obtained from serum, urine, saliva, and cells from cystic fibrosis homozygotes and heterozygotes, were detected, purified, and characterized. properties of these factors are similar to those detected by other ciliated systems in mussel gills and rabbit trachea. although non ... | 1980 | 7002621 |
| comparison of mutagen accumulation in 3 estuarine species using the salmonella/microsome activation system. | 3 estuarine organisms- oysters (crassostrea virginica), sea squirts (mogulla sp.), and shrimp (peneaus sp.)-were examined for ames test detectable levels of mutagens. whole-tissue extracts of these organisms were made and tested using s. typhimurium strains ta98, ta100, ta1535, ta1537 and ta1538, with and without s9 activation. positive results were obtained with sea squirts and shrimp extracts. activation was not necessary to show activity. toxicity was encountered with oyster extracts. histidi ... | 1981 | 7022185 |
| aconitase from the oyster crassostrea virginica. | 1. the presence of aconitase activity in the oyster. crassostrea virginica, has been demonstrated. 2. low levels of activity were found in the different tissues with highest level in digestive diverticular and lowest level in muscle. 3. the conversion of both citrate and iso-citrate to cis-aconitate suggests the presence of an enzyme system capable of utilizing these compounds at a slow but demonstrable rate to give classically expected results. 4. comparison of the oyster enzyme with aconitase ... | 1982 | 7116815 |
| isolation of vibrio cholerae serotype o1 from the eastern oyster, crassostrea virginica. | two strains of vibrio cholerae serotype o1 inaba were isolated from eastern oysters, crassostrea virginica, collected from estuarine waters in florida during april 1980. the oyster meats and waters from which the oysters were collected had low fecal coliform counts, and the area had no prior evidence of sewage contamination. | 1981 | 7235700 |
| morphology of a reo-like virus isolated from juvenile american oysters (crassotrea virginica). | rotational enhancement of image detail performed on a proposed new serotype of reovirus suggested icosahedral symmetry of t = 3 with some morphological features of members of the reoviridae family. | 1980 | 7351535 |
| uptake and retention of vibrio cholerae o1 in the eastern oyster, crassostrea virginica. | vibrio cholerae 01, the causative agent of cholera, is known to persist in estuarine environments as endogenous microflora. the recent introduction of v. cholerae 01 into estuaries of the north and south american continents has stimulated the need to determine the effect of controlled purification on reducing this pathogen in edible molluscan shellfish. experiments defined parameters for the uptake and retention of v. cholerae 01 in tissues of crassostrea virginica, and these parameters were com ... | 1995 | 7487003 |
| accumulation of polychlorinated terphenyls in aquatic biota of an estuarine creek. | aroclor 5432, a mixture of polychlorinated terphenyls (pct), was detected in several biological compartments including saltmarsh cordgrass (spartina alterniflora), american oysters (crassostrea virginica), red-jointed fiddler crabs (uca minax), wharf crabs (sesarma reticulatum), and mummichogs (fundulus heteroclitus) collected from tabbs creek. this tidal creek is located in the southern chesapeake bay region and contains sediments with high concentrations of pct. samples were collected at four ... | 1993 | 7507821 |
| suppression of chemiluminescence of eastern oyster (crassostrea virginica) hemocytes by the protozoan parasite perkinsus marinus. | experiments were conducted to determine the ability of the protistan parasite, perkinsus marinus, to inhibit chemiluminescence of hemocytes from the eastern oyster, crassostrea virginica. luminol-enhanced chemiluminescence (cl) was used to measure the production of reactive oxygen intermediates (roi) generated by oyster hemocytes using zymosan as a stimulant. to determine whether p. marinus suppresses roi evoked from zymosan-stimulated hemocytes, live or heat killed p. marinus in filtered estuar ... | 1995 | 7556800 |
| effect of dilution, incubation time, and temperature of enrichment on cultural and pcr detection of vibrio cholerae obtained from the oyster crassostrea virginica. | the recovery of vibrio cholerae 01 by culture from the oyster crassostrea virginica and detection of the cholera toxin gene by polymerase chain reaction were evaluated using various enrichment procedures in alkaline peptone water. the effects of dilutions (1:10 and 1:100), incubation times (6-8 and 18-21 h), and incubation temperatures (35 and 42 degree) were determined. recovery of v.cholerae was significantly greater (p<0.05) from oyster homogenates diluted 1:100 in alkaline peptone water and ... | 1995 | 7603474 |
| a sensitive and specific dna probe for the oyster pathogen haplosporidium nelsoni. | haplosporidium nelsoni is a pathogen of the eastern oyster, crassostrea virginica, along the middle atlantic coast of the u.s. genomic dna was extracted from h. nelsoni plasmodia and small subunit (ssu) rdna was amplified by pcr, cloned and sequenced. the sequence of h. nelsoni ssu rdna was aligned with that of another haplosporidian, minchinia teredinis, and with ssu rdna data of c. virginica and various protists in genbank. a 21-base oligonucleotide unique to h. nelsoni, designated msx1347, wa ... | 1995 | 7620459 |
| metals in some lagoons of mexico. | the concentrations of metals, cd, cu, fe, mn, ni, pb, and zn were determined in some lagoons to establish the level of metal pollution. the lagoons studied were alvarado lagoon, veracruz; san andres lagoon, tamaulipas; and terminos lagoon, campeche. the concentrations were determined in water, oyster (crassostrea virginica), and sediments. metals were accumulated in either oysters or sediments. cu and zn were higher in oysters and fe and mn were higher in sediments. the results in water samples ... | 1995 | 7621796 |
| a semiquantitative pcr assay for assessing perkinsus marinus infections in the eastern oyster, crassostrea virginica. | a 3.2-kb fragment of perkinsus marinus dna was cloned and sequenced. a noncoding domain was identified and targeted for the development of a semiquantitative polymerase chain reaction (pcr) assay for the presence of p. marinus in eastern oyster tissues. the assay involves extracting total dna from oyster hemolymph and using 1 microgram of that dna as template in a stringent pcr amplification with oligonucleotide primers that are specific for the p. marinus 3.2-kb fragment. with this assay, we ca ... | 1995 | 7623200 |
| characterization of the small subunit ribosomal rna gene of the oyster parasite haplosporidium costale. | the small subunit ribosomal rna (ssu rrna) gene of the oyster parasite haplosporidium costale was characterized from spore dna by polymerase chain reaction (pcr) and molecular cloning. sequence analysis showed that identical clones were obtained from separate batches of spore samples. the gene is 1791 nucleotides in size. it has 84.5% sequence similarity to that of a related oyster parasite, haplosporidium nelsoni, 71.8% similarity to that of its oyster host, crassostrea virginica, and 75.4% sim ... | 1995 | 7670599 |
| hydrocarbon concentrations in the american oyster, crassostrea virginica, in laguna de terminos, campeche, mexico. | | 1995 | 7742630 |
| small subunit ribosomal rna gene sequence of minchinia teredinis (haplosporidia: haplosporidiidae) and a specific dna probe and pcr primers for its detection. | minchinia teredinis is a pathogen of wood-boring molluscs (shipworms), teredo spp., along the middle atlantic coast of the u.s. genomic dna was extracted from m. teredinis spores and small subunit (ssu) rdna was amplified by pcr, cloned, and sequenced. the sequence of m. teredinis ssu rdna was aligned with that of haplosporidium nelsoni and various protists in genbank. a 22-base oligonucleotide probe unique to m. teredinis, designated min702, was commercially synthesized and tested for sensitivi ... | 1995 | 7745284 |
| further evidence of regular sporulation by haplosporidium nelsoni in small oysters, crassostrea virginica. | during a field study to determine the susceptibility of the pacific oyster crassostrea gigas to chesapeake bay oyster pathogens, sporulation of haplosporidium nelsoni was observed in eastern oysters crassostrea virginica being used as controls. the c. virginica were obtained from 2 sources on 19 may 1993, a wild population in the upper rappahannock river, virginia (59.6 mm mean shell height) and a hatchery-reared population from chesapeake mari-culture that was held in the wye river, maryland (4 ... | 1994 | 7799147 |
| inhibition of in vitro replication of the oyster parasite perkinsus marinus by the natural iron chelators transferrin, lactoferrin, and desferrioxamine. | the mammalian iron-binding proteins transferrin and lactoferrin, the bactericidal peptide lactoferricin b, and the bacterial siderophore desferrioxamine were tested for their ability to inhibit the in vitro replication of the oyster parasite perkinsus marinus. all three chelators were effective in reducing the parasite proliferation in a dose-dependent manner. lactoferricin b, a peptide of lactoferrin that exhibits bactericidal properties unrelated to iron chelation, had no inhibitory activity o ... | 1994 | 7883057 |
| small subunit ribosomal rna gene sequence of the oyster parasite perkinsus marinus. | the small subunit rrna gene of the oyster pathogen perkinsus marinus was characterized from cells of infected oyster hemolymph by polymerase chain reaction and molecular cloning. the gene, 1,793 nucleotides in size, has 77.2% sequence similarity to that of its host, the eastern oyster crassostrea virginica. the sequence was confirmed using recently available in vitro cultures of p. marinus. dna from pure p. marinus culture was amplified with specific primers synthesized according to the sequence ... | 1993 | 8193669 |
| atrial natriuretic peptides in the heart and hemolymph of the oyster, crassostrea virginica: a comparison with vertebrates. | 1. the content of atrial natriuretic peptides (anps) in the auricles of oysters, crassostrea virginica, was significantly (p < 0.01) greater than in their ventricles. 2. high-performance gel permeation chromatography (hp-gpc) followed by anf radioimmunoassay revealed two peaks in both oyster and vertebrate (rat) hearts--a major peak where the 12.6-14 kda anf prohormone elutes and a smaller peak where the pure human form of anf elutes. 3. hp-gpc evaluation followed by proanf 31-67 radioimmunoassa ... | 1993 | 8281751 |
| direct plating procedure for enumerating vibrio vulnificus in oysters (crassostrea virginica). | a procedure for enumerating and identifying vibrio vulnificus in oysters was developed and evaluated. this method consists of growth on a direct plating medium (vve medium) for isolating the organism from shellfish tissues, followed by biochemical tests for differentiating and identifying presumptively positive isolates. densities of v. vulnificus are reliably obtained in 2 to 4 days, and as few as 10 culturable cells per 100 g can be identified. the procedure was evaluated by using a dna probe ... | 1993 | 8285658 |
| cellular responses of oysters infected with haplosporidium nelsoni: changes in circulating and tissue-infiltrating hemocytes. | the protozoan parasite haplosporidium nelsoni (msx) elicits an inflammatory-type response in oysters, crassostrea virginica. we assayed circulating hemocytes of oysters exposed to h. nelsoni to quantify the effects of parasitism, selection for resistance, and season on total and differential counts. all factors had a significant (p < 0.02) effect on total counts, but explained relatively little of the overall variance [season (12%) > selection (4%) > infection (2%)]. circulating hemocyte densiti ... | 1993 | 8426068 |
| in vivo chemoactivation of oyster hemocytes induced by bacterial secretion products. | movements of tissue hemocytes in the eastern oyster crassostrea virginica were monitored and quantified by image analysis of sections following inoculation with agar cores containing escherichia coli or cell-free medium on which the bacteria had previously grown. hemocytes respond to the presence of live bacteria by accumulating in widely dispersed areas of tissue surrounding the gut and digestive diverticula. the response is rapid and evident within 40 min, is maximal at 1 hr, and declines by 3 ... | 1995 | 8568283 |
| atrial natriuretic peptide gene expression within invertebrate hearts. | the present investigation was designed to (1) determine if atrial natriuretic factor gene expression occurs within invertebrates as well as within vertebrates; (2) determine whether the product of this gene expression is the 126-amino-acid atrial natriuretic factor prohormone or some other molecular species; and (3) evaluate within the same invertebrates if the products of atrial natriuretic factor gene expression are released into their circulation. utilizing a very sensitive rnase protection a ... | 1995 | 8575660 |
| phylogeny of the haplosporidia (eukaryota: alveolata) based on small subunit ribosomal rna gene sequence. | the phylogenetic position of the phylum haplosporidia was investigated with the complete small subunit rrna gene sequences from 5 species in the phylum: haplosporidium nelsoni and haplosporidium costale, parasites of the eastern oyster crassostrea virginica; haplosporidium louisiana, a parasite of the mudcrab panopeus herbstii; minchinia teredinis, a parasite of shipworms (teredo spp.) and urosporidium crescens, a hyperparasite found in metacercariae of the trematode megalophallus sp. in the blu ... | 1996 | 8691370 |
| offshore suspension relaying to reduce levels of vibrio vulnificus in oysters (crassostrea virginica). | oysters naturally contaminated with 10(3) to 10(4) most probable numbers (mpn) of vibrio vulnificus per g were relayed to offshore waters (salinity, 30 to 34 ppt), where they were suspended in racks at a depth of 7.6 m. v. vulnificus counts in oysters were reduced to < 10 mpn/g within 7 to 17 days in five of the six studies. at the end of the studies (17 to 49 days), v. vulnificus levels were reduced further and ranged from a mean of 0.23 to 2.6 mpn/g. oyster mortalities during relaying were < 6 ... | 1996 | 8837445 |
| contribution of perkinsus marinus extracellular products in the infection of eastern oysters (crassostrea virginica). | | 1996 | 8931368 |
| phylogenetic position of the spirochetal genus cristispira. | comparative sequence analysis of 16s rrna genes was used to determine the phylogenetic relationship of the genus cristispira to other spirochetes. since cristispira organisms cannot presently be grown in vitro, 16s rrna genes were amplified directly from bacterial dna isolated from cristispira cell-laden crystalline styles of the oyster crassostrea virginica. the amplified products were then cloned into escherichia coli plasmids. sequence comparisons of the gene coding for 16s rrna (rdna) insert ... | 1996 | 8975621 |
| in vitro activity of the limulus antimicrobial peptide tachyplesin i on marine bivalve pathogens | tachyplesin 1 is an antimicrobial peptide extracted from hemocytes of the japanese horseshoe crab tachypleus tridentatus. we studied the in vitro activity of tachyplesin i against bivalve pathogens: the oyster parasites bonamia ostreae, the intrahemocytic parasite of the flat oyster ostrea edulis and perkinsus marinus, the histozoic parasite of the eastern oyster crassostrea virginica, and the bacterium vibrio p1, pathogenic for the clam tapes philippinarum. viability of the protozoans was asses ... | 1997 | 9056468 |
| haplosporidium nelsoni (msx) epizootic in the piscataqua river estuary (maine/new hampshire, usa.). | a major epizootic of haplosporidium nelsoni occurred during 1995 in the piscataqua river estuary, near the northern distributional limit of the parasite. prevalence of h. nelsoni in samples of oysters, crassostrea virginica, collected between 5 september and 18 december 1995 from sites in maine and new hampshire ranged from 15 to 81%, with up to 50% systemic infections. associated proportions of dead oysters ranged from 25 to 83%. the epizootic was most likely triggered by unusually warm and dry ... | 1997 | 9057712 |
| magnetic immunoseparation pcr assay (mipa) for detection of hepatitis a virus (hav) in american oyster (crassostrea virginica). | in order to detect the low numbers of hepatitis a viral (hav) particles which may potentially be present in food and cause a serious illness, an original procedure which combines immunomagnetic separation and pcr is described. the use of streptavidin magnetic beads coated with biotinylated human anti-hav igg allows virus capture and the removal of the rt-pcr inhibitory compounds which usually are present in shellfish extracts. following immunomagnetic capture, the separated hav were lysed, the b ... | 1997 | 9081302 |
| effects of experience on crab foraging in a mobile and a sedentary species | the effects of experience on prey and prey-patch choice were compared between two species of marine predatory crabs. the blue crab, callinectes sapidus rathbun, is highly mobile and forages in a variety of estuarine and lagoonal habitats. the atlantic mud crab, panopeus herbstii h. milne-edwards, is smaller and less mobile and is found mostly in oyster reefs and on shelly bottoms. in the laboratory, crabs were offered a choice between two prey types (juvenile hard clams, mercenaria mercenaria li ... | 1997 | 9236012 |
| hydrocarbon concentrations in oysters (crassostrea virginica) and recent sediments from three coastal lagoons in tabasco, mexico. | | 1997 | 9256397 |
| modulation of crassostrea virginica hemocyte reactive oxygen species production by listonella anguillarum. | luminol- and lucigenin-augmented chemiluminescence (cl) were used to evaluate the ability of listonella (formerly vibrio) anguillarum to stimulate the production of reactive oxygen species (ros) by crassostrea virginica hemocytes. whereas heat-killed l. anguillarum stimulated hemocyte cl in the lucigenin system, viable l. anguillarum did not. neither viable nor heat-killed bacteria stimulated hemocyte production of luminol cl. metabolically active l. anguillarum generated ros, as indicated by lu ... | 1997 | 9303272 |
| alpha-kdoase activity in oyster and synthesis of alpha- and beta-4-methylumbelliferyl ketosides of 3-deoxy-d-manno-octulosonic acid. | although alpha- and beta-linked 3-deoxy-d-manno-octulosonic acid (kdo) is found in lipopolysaccharides (lpss) of gram-negative bacteria, capsular polysaccharides of microorganisms, and plants, very little is known about its degradation. using both thin-layer chromatography and the periodate-thiobarbituric acid reaction, we found that the hepatopancreas of oyster (crassostrea virginica) contained an enzyme (alpha-kdoase) capable of releasing alpha-linked kdo from lpss. to facilitate the studies o ... | 1997 | 9334217 |
| in vitro interactions between hemocytes of the eastern oyster, crassostrea virginica gmelin, 1791 and cryptosporidium parvum oocysts. | it was demonstrated by an in vitro slide phagocytosis assay that hemocytes of the eastern oyster, crassostrea virginica gmelin, 1791 are capable of rapid recognition and internalization of infectious cryptosporidium parvum (aucp-1 strain) oocysts. the incubation of hemocyte monolayers (8.5 x 10(4) cells) that had received 6.8 x 10(5) or 3.4 x 10(5) oocysts was arrested at 5, 15, 30, 60, 90, and 120 min and the oocytes detected by acid-fast stain and immunofluorescent antibody (ifat). an average ... | 1997 | 9379306 |
| viral gastroenteritis associated with eating oysters -- louisiana, december 1996-january 1997. | viral gastroenteritis outbreaks caused by caliciviruses (i.e., norwalk-like viruses or small round-structured viruses) have been associated with eating contaminated shellfish, particularly oysters (crassostrea virginica). this report describes the findings of the investigation of an outbreak of oyster-associated viral gastroenteritis in louisiana during the 1996-97 winter season and implicates sewage from oyster harvesting vessels as the probable cause of contaminated oysters. | 1997 | 9393656 |
| acid phosphatase activity in perkinsus marinus, the protistan parasite of the american oyster, crassostrea virginica. | the effect of temperature (4, 12, 20, and 28 c) and osmolality (400, 570, and 840 mosm/kg) on extracellular acid phosphatase (ap) secretion in vitro, and ultrastructural localization of ap activity in the parasite were investigated. the extracellular ap secretion by perkinsus marinus was cell density dependent (p < 0.001). increasing culture temperatures resulted in increased p. marinus proliferation concomitant with ap secretion (p < 0.0001). ap secretion was similar in p. marinus cultured at 4 ... | 1997 | 9406785 |
| phages infecting vibrio vulnificus are abundant and diverse in oysters (crassostrea virginica) collected from the gulf of mexico. | phages infecting vibrio vulnificus were abundant (> 10(4) phages g of oyster tissue-1) throughout the year in oysters (crassostrea virginica) collected from estuaries adjacent to the gulf of mexico (apalachicola bay, fla.; mobile bay, ala.; and black bay, la.). estimates of abundance ranged from 10(1) to 10(5) phages g of oyster tissue-1 and were dependent on the bacterial strain used to assay the sample. v. vulnificus was near or below detection limits (< 0.3 cell g-1) from january through marc ... | 1998 | 9435088 |
| survival of infectious cryptosporidium parvum oocysts in seawater and eastern oysters (crassostrea virginica) in the chesapeake bay. | oocysts of cryptosporidium parvum placed in artificial seawater at salinities of 10, 20, and 30 ppt at 10 degrees c and at 10 ppt at 20 degrees c were infectious after 12 weeks. those placed in seawater at 20 ppt and 30 ppt at 20 degrees c were infectious for 8 and 4 weeks, respectively. these findings suggested that oocysts could survive in estuarine waters long enough to be removed by filter feeders such as oysters. thereafter, 30 eastern oysters, crassostrea virginica, were collected with a d ... | 1998 | 9501446 |
| influence of water temperature and salinity on vibrio vulnificus in northern gulf and atlantic coast oysters (crassostrea virginica). | this study investigated the temperature and salinity parameters associated with waters and oysters linked to food-borne vibrio vulnificus infections. v. vulnificus was enumerated in oysters collected at three northern gulf coast sites and two atlantic coast sites from july 1994 through september 1995. two of these sites, black bay, la., and apalachicola bay, fla., are the source of the majority of the oysters implicated in v. vulnificus cases. oysters in all gulf coast sites exhibited a similar ... | 1998 | 9546182 |
| a comparison of the chemiluminescent response of crassostrea virginica and morone saxatilis phagocytes to zymosan and viable listonella anguillarum. | if reactive oxygen species (ros) produced by hemocytes of the eastern oyster, crassostrea virginica, impart bactericidal activity, exposure of hemocytes to bacteria should result in increased ros generation. in an earlier study, this hypothesis was tested using luminol- and lucigenin-augmented chemiluminescence (cl) to measure ros production. the bacterium listonella anguillarum did not stimulate a net increase in hemocyte-derived cl, and it was suggested that bacterial antioxidants might suppre ... | 1998 | 9617583 |
| altered response of oyster hemocytes to haplosporidium nelsoni (msx) plasmodia treated with enzymes or metabolic inhibitors. | to avoid phagocytosis, parasites may mask themselves with host-like molecules that prevent recognition as nonself or they may produce substances that interfere with host cellular defenses. the protozoan parasite haplosporidium nelsoni, which causes msx disease in the eastern oyster crassostrea virginica, is not ingested by host hemocytes. to assess potential avoidance mechanisms, oyster hemocytes were incubated with plasmodial stages of the parasite that had been pretreated with one of a variety ... | 1998 | 9709017 |
| perkinsus marinus tissue distribution and seasonal variation in oysters crassostrea virginica from florida, virginia and new york. | perkinsus marinus infection intensity was measured in eastern oysters crassostrea virginica collected in october and december 1993, and march, may, and july 1994 from 3 u.s. sites: apalachicola bay (fl), chesapeake bay (va), and oyster bay (ny). gill, mantle, digestive gland, adductor muscle, hemolymph, and remaining tissue (including gonadal material and rectum) were dissected from 20 oysters from each site at each collection time. samples were separately diagnosed for p. marinus infections by ... | 1998 | 9789979 |
| detection of cryptosporidium oocysts and giardia cysts in the tissues of eastern oysters (crassostrea virginica) carrying principal oyster infectious diseases. | the potential cross-reactivity of the combined cryptosporidium/giardia direct immunofluorescence antibodies (ifa) of merifluor and hydrofluor-combo tests was examined against tissues containing known developmental stages of 12 pathogens causing the principal infectious diseases in oysters. spores of haplosporidium nelsoni and haplosporidium costale produced positive acid-fast stain (afs) reactions similar in intensity to cryptosporidium parvum oocysts. hexamia nelsoni trophozoites produced posit ... | 1998 | 9794651 |
| species-specificity and sensitivity of a pcr-based assay for perkinsus marinus in the eastern oyster, crassostrea virginica: a comparison with the fluid thioglycollate assay. | we examined the species-specificity and sensitivity of a polymerase chain reaction (pcr)-based assay for perkinsus marinus and compared its overall performance with the fluid thioglycollate medium (ftm) assay on oyster (crassostrea virginica) hemolymph, mantle, and rectum samples. our results indicated that the pcr-based methodology is species-specific because perkinsus olseni, perkinsus atlanticus, and perkinsus spp. dnas were not amplified with the pcr primers developed for p. marinus diagnosi ... | 1998 | 9920320 |
| factors influencing in vitro killing of bacteria by hemocytes of the eastern oyster (crassostrea virginica). | a tetrazolium dye reduction assay was used to study factors governing the killing of bacteria by oyster hemocytes. in vitro tests were performed on bacterial strains by using hemocytes from oysters collected from the same location in winter and summer. vibrio parahaemolyticus strains, altered in motility or colonial morphology (opaque and translucent), and listeria monocytogenes mutants lacking catalase, superoxide dismutase, hemolysin, and phospholipase activities were examined in winter and su ... | 1999 | 10388697 |
| characterization of two perkinsus spp. from the softshell clam, mya arenaria using the small subunit ribosomal rna gene. | sequence analysis and riboprinting of the small subunit ribosomal rna genes were used to characterize two morphologically different perkinsus species isolates from the gill (g117) and the hemolymph (h49) of the softshell clam, mya arenaria. sequence data of the polymerase chain reaction amplified ribosomal rna loci of g117 and h49 indicated that these genes are 1803 and 1806 base-pair long, respectively. a sequence similarity of > 98.9% was calculated among ribosomal rna sequences of the two iso ... | 1999 | 10461386 |
| perkinsus marinus extracellular protease modulates survival of vibrio vulnificus in eastern oyster (crassostrea virginica) hemocytes. | the in vitro effects of the perkinsus marinus serine protease on the intracellular survival of vibrio vulnificus in oyster hemocytes were examined by using a time-course gentamicin internalization assay. results showed that protease-treated hemocytes were initially slower to internalize v. vulnificus than untreated hemocytes. after 1 h, the elimination of v. vulnificus by treated hemocytes was significantly suppressed compared with hemocytes infected with invasive and noninvasive controls. our d ... | 1999 | 10473449 |
| analysis of the effects of perkinsus marinus proteases on plasma proteins of the eastern oyster (crassostrea virginica) and the pacific oyster (crassostrea gigas). | we employed two in vitro buffer systems to determine the potential pathogenic effects of perkinsus marinus serine proteases on the plasma proteins of the eastern oyster (crassostrea virginica) and the pacific oyster (crassostrea gigas). specifically, this study characterized the oyster plasma protein targets of p. marinus proteases. additionally, protease-specific inhibitory activity was revealed upon comparison of artificial (pbs) and endogenous (plasma-based) diluents employed during protease ... | 1999 | 10486230 |
| oyster metallothionein as an oxyradical scavenger: implications for hemocyte defense responses. | in order to better understand the interplay between metallothionein (mt) and reactive oxygen species (ros) in oyster hemocytes, studies of the hydrogen peroxide (h2o2) scavenging properties of mt were carried out in a cell-free system. mammalian mt is involved in protection against oxidative stress by virtue of its ability to scavenge free radicals; therefore, the h2o2 scavenging potentials of crassostrea virginica and rabbit mts were compared. oyster and rabbit mts showed similar dose-dependent ... | 1999 | 10512455 |
| effects of a commercial heat-shock process on vibrio vulnificus in the american oyster, crassostrea virginica, harvested from the gulf coast. | oysters (crassostrea virginica) harvested from the gulf coast, containing 10(2) to 10(4) most probable number (mpn) per gram of vibrio vulnificus, were subjected to a commercial heat-shock process. after 1 to 4 min at internal oyster meat temperatures exceeding 50 degrees c, shellstock oysters were shucked, chilled, washed, and packed. v. vulnificus and total bacterial levels in gulf coast oysters were significantly reduced from 1 to 4 logs in the finished product. similar reductions were not ob ... | 1999 | 10571315 |
| patterns in metazoan parasite communities of some oyster species. | metazoan parasite communities of crassostrea gigas and ostrea edulis from great britain, crassostrea virginica from mexico, and saccostrea commercialis from australia are described and summarized in terms of species composition, species richness, total number of individuals and dominance. metazoan parasite communities in all host species were composed of turbellarians and the metacercarial stage of digeneans, with the exception of s. commercialis where only metacercariae were found. arthropods, ... | 1999 | 10654396 |
| whole animal and gill tissue oxygen uptake in the eastern oyster, crassostrea virginica: effects of hypoxia, hypercapnia, air exposure, and infection with the protozoan parasite perkinsus marinus(1). | the eastern oyster, crassostrea virginica, lives in shallow coastal waters and experiences many different environmental extremes including hypoxia, hypercapnia and air exposure and many oysters are infected with the protozoan parasite perkinsus marinus. the effects of these conditions on oyster metabolism, as measured by oxygen uptake, were investigated. mild hypercapnia had no effect on the ability of oysters to regulate oxygen uptake in hypoxic water, as measured by the b2 coefficient of oxyge ... | 2000 | 10713278 |
| selective accumulation may account for shellfish-associated viral illness. | from 1991 through 1998, 1,266 cases of shellfish-related illnesses were attributed to norwalk-like viruses. seventy-eight percent of these illnesses occurred following consumption of oysters harvested from the gulf coast during the months of november through january. this study investigated the ability of eastern oysters (crassostrea virginica) to accumulate indicator microorganisms (i.e., fecal coliforms, escherichia coli, clostridium perfringens, and f(+) coliphage) from estuarine water. one-w ... | 2000 | 10742214 |
| changes in the electrophoretic profiles of gill mucus proteases of the eastern oyster crassostrea virginica in response to infection by the turbellarian urastoma cyprinae. | urastoma cyprinae occurs on the gills of various bivalves species, including the eastern oyster crassostrea virginica. while the worm is known to cause severe gill disruption in mussels, no evidence of this nature has been described for oysters. nonetheless, high levels of u. cyprinae have been reported in oysters, which may, in turn, reduce the oyster's overall condition. u. cyprinae is strongly attracted to oyster gill mucus, which is suggested to play an active role in the worm's feeding acti ... | 2000 | 10772329 |
| a quantitative competitive polymerase chain reaction assay for the oyster pathogen perkinsus marinus. | a quantitative competitive polymerase chain reaction (qcpcr) assay was developed for the oyster parasite perkinsus marinus. pcr primers for the rrna gene region of p. marinus amplified dna isolated from p. marinus but not from perkinsus atlanticus, crassostrea virginica, or the dinoflagellates peridinium sp., gymnodinium sp., or amphidinium sp. a mutagenic primer was used to create a competitor plasmid molecule identical to the p. marinus target dna sequence except for a 13-bp deletion. both p. ... | 2000 | 10958465 |
| detection of bonamia ostreae based on small subunit ribosomal probe. | bonamia ostreae is a protozoan parasite of the flat oyster, ostrea edulis, which has caused significant loss of oysters in europe over the last decade. b. ostreae was purified from infected flat oysters and dna was extracted. the nearly complete small subunit rdna gene of b. ostreae was amplified using universal oligonucleotides and the pcr product was cloned and sequenced. blast research with this sequence revealed similarities to haplosporidium nelsoni, haplosporidium costale, and minchinia te ... | 2000 | 10963400 |
| additional evidence that juvenile oyster disease is caused by a member of the roseobacter group and colonization of nonaffected animals by stappia stellulata-like strains. | juvenile oyster disease (jod) causes significant annual mortalities of hatchery-produced eastern oysters, crassostrea virginica, cultured in the northeast. we have reported that a novel species of the alpha-proteobacteria roseobacter group (designated cvsp) was numerically dominant in jod-affected animals sampled during the 1997 epizootic on the damariscotta river, maine. in this study we report the isolation of cvsp bacteria from jod-affected oysters during three separate epizootics in 1998. th ... | 2000 | 10966410 |
| transmission of the haplosporidian parasite msx haplosporidium nelsoni to the eastern oyster crassostrea virginica in an upweller system. | the haplosporidian oyster parasite msx (multinucleated sphere x) haplosporidium nelsoni was transmitted to eastern oysters crassostrea virginica. hatchery-raised, msx-free juvenile oysters were placed in upweller tanks. water to the tanks was filtered through a screen with 1 mm2 openings and originated from the water column overlaying naturally infected oysters beds (msx prevalence 17 to 57%). msx was diagnosed by histopathological analysis. msx-disease (57% prevalence) with increased mortality ... | 2000 | 11023255 |
| uptake and interconversion of fluorescent lipid analogs in the protozoan parasite, perkinsus marinus, of the oyster, crassostrea virginica. | uptake, distribution, and interconversion of fluorescent lipid analogs (phosphatidylcholine, pc; cholesteryl ester, che; phosphatidylethanolamine, pe; palmitic acid, c16; sphingomyelin, sm) by the two life stages, meront and prezoosporangium, of the oyster protozoan parasite, perkinsus marinus, were investigated. class composition of these two life stages and lipid contents in meront cells were also examined. both meronts and prezoosporangia incorporated and modified fluorescent lipids from the ... | 2000 | 11038307 |
| evaluation of two direct plating methods using nonradioactive probes for enumeration of vibrio parahaemolyticus in oysters. | oysters (crassostrea virginica) were collected monthly from may 1998 to april 1999 from mobile bay, ala., and analyzed to determine vibrio parahaemolyticus densities at zero time and after 5, 10, and 24 h of postharvest storage at 26 degrees c. after 24 h of storage at 26 degrees c, oysters were transferred to a refrigerator at 3 degrees c and then analyzed 14 to 17 days later. the v. parahaemolyticus numbers were determined by the most-probable-number procedure using alkaline phosphatase-labele ... | 2001 | 11157236 |
| a unique sialidase that cleaves the neu5gcalpha2-->5-o(glycolyl)neu5gc linkage: comparison of its specificity with that of three microbial sialidases toward four sialic acid dimers. | we found that the hepatopancreas of oyster, crassostrea virginica, contained a sialidase capable of releasing neu5gc from the novel polysialic acid chain (-->5-o(glycolyl)neu5gcalpha2-->)n more efficiently than from the conventional type of polysialic acid chains, (-->8neu5acalpha2-->)n, or (-->8neu5gcalpha2-->)n. we have partially purified this novel sialidase and compared its reactivity with that of microbial sialidases using four different sialic acid dimers, neu5gcalpha2-->5-o(glycolyl)neu5g ... | 2001 | 11162485 |