PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Ostreidae”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2004

Restriction enzyme digestion chromosome banding in Crassostrea and Ostrea species: comparative karyological analysis within Ostreidae.

Reliable banding techniques are a major necessity for genetic research in oysters. In this study, we carried out the cytogenetic characterization of four oyster species (family Ostreidae) using restriction endonuclease treatments. Chromosomes were treated with three different restriction enzymes, stained with Giemsa, and examined for banding patterns. The following species were studied: Crassostrea gigas (2n = 20; total number of bands with ApaI, 74; HaeIII, 61; PstI, 76), Crassostrea angulata (2n = 20; ApaI, 62; HaeIII, 61; PstI, 55) (subfamily Crassostreinae), Ostrea edulis (2n = 20; ApaI, 82; HaeIII, 59; PstI, 66), and Ostrea conchaphila (2n = 20; ApaI, 68; HaeIII, 62; PstI, 69) (subfamily Ostreinae). Treatment of samples with ApaI, HaeIII, and PstI produced specific banding patterns, which demonstrates the potential of these enzymes for chromosome banding in oysters. This is of special interest, since it has been recently shown in mammalian chromosomes that restriction enzyme banding is compatible with fluorescence in situ hybridization. This study therefore provides a fundamental step in genome mapping of oysters, since chromosome banding with restriction enzymes facilitates physical gene mapping in these important aquaculture species. The analysis of the banded karyotypes revealed a greater similarity within the genera of Crassostrea and Ostrea than between them.

Animals↗
PubMed2005

Cadmium exposure affects mitochondrial bioenergetics and gene expression of key mitochondrial proteins in the eastern oyster Crassostrea virginica Gmelin (Bivalvia: Ostreidae).

Cadmium is a ubiquitous and extremely toxic metal, which strongly affects mitochondrial function of aquatic organisms in vitro; however, nothing is known about the in vivo effects of sublethal concentrations of this metal on mitochondrial bioenergetics. We have studied the effects of exposure to 0 (control) or 25 microg L-1 (Cd-exposed) Cd2+ on mitochondrial function and gene expression of key mitochondrial proteins in the eastern oyster Crassostrea virginica. Cadmium exposure in vivo resulted in considerable accumulation of cadmium in oyster mitochondria and in a significant decrease of ADP-stimulated respiration (state 3) by 30% indicating impaired capacity for ATP production. The decrease in state 3 respiration was similar to the level of inhibition expected from the direct effects of cadmium accumulated in oyster mitochondria. On the other hand, while no effect on proton leak was expected based on the mitochondrial accumulation of cadmium, Cd-exposed oysters in fact showed a significant decline of the proton leak rate (state 4+respiration) by 40%. This suggested a downregulation of proton leak, which correlated with a decrease in mRNA expression of a mitochondrial uncoupling protein UCP6 and two other potential uncouplers, mitochondrial substrate carriers MSC-1 and MSC-2. Expression of other key mitochondrial proteins including cytochrome c oxidase, adenine nucleotide transporter and voltage dependent anion channel was not affected by cadmium exposure. Adenylate energy charge (AEC) was significantly lower in Cd-exposed oysters; however, this was due to higher steady state ADP levels and not to the decrease in tissue ATP levels. Our data show that adjustment of the proton leak in cadmium-exposed oysters may be a compensatory mechanism, which allows them to maintain normal mitochondrial coupling and ATP levels despite the cadmium-induced inhibition of capacity for ATP production.

Actins↗
PubMed2005

Tissue-specific accumulation of cadmium in subcellular compartments of eastern oysters Crassostrea virginica Gmelin (Bivalvia: Ostreidae).

Cadmium distribution was studied in different subcellular fractions of gill and hepatopancreas tissues of eastern oysters Crassostrea virginica. Oysters were exposed for up to 21 days to low sublethal Cd concentrations (25 microg L(-1)). Gill and hepatopancreas tissues were sampled and divided into organelle fractions and cytosol by differential centrifugation. Organelle content of different fractions was verified by activities of marker enzymes, citrate synthase and acid phosphatase for mitochondria and lysosomes, respectively. In both tissue types, there was a significant accumulation of cadmium in cytosol reaching 230-350 ng mg(-1) protein. Among organelles, mitochondria were the main target for Cd bioaccumulation in gills (250-300 ng mg(-1) protein), whereas in hepatopancreas tissues, the highest cadmium accumulation occurred in lysosomes (90-94 ng mg(-1) protein). Although 75-83% of total cadmium burden was associated with the cytosol reflecting high volume fraction of this compartment, Cd concentrations in organelle fractions reached levels that could cause dysfunction of mitochondria and lysosomes. Organ- and organelle-specific patterns of cadmium bioaccumulation support our previous in vivo studies, which showed adverse effects of cadmium exposures on mitochondrial oxidation in gills and on the lysosomal system of hepatopancreas. This may have important implications for the development of biomarkers of effect for heavy metals and for understanding the mechanisms of toxic effects of metals.

Acid Phosphatase↗
PubMed2004

Cadmium effects on mitochondrial function are enhanced by elevated temperatures in a marine poikilotherm, Crassostrea virginica Gmelin (Bivalvia: Ostreidae).

Marine intertidal mollusks, such as oysters, are exposed to multiple stressors in estuaries, including varying environmental temperature and levels of trace metals, which may interactively affect their physiology. In order to understand the combined effects of cadmium and elevated temperature on mitochondrial bioenergetics of marine mollusks, respiration rates and mitochondrial volume changes were studied in response to different cadmium levels (0-1000 micromol l(-1)) and temperatures (15, 25 and 35 degrees C) in isolated mitochondria from the eastern oyster Crassostrea virginica acclimated at 15 degrees C. It was found that both cadmium and temperature significantly affect mitochondrial function in oysters. Elevated temperature had a rate-enhancing effect on state 3 (ADP-stimulated) and states 4 and 4+ (representative of proton leak) respiration, and the rate of temperature-dependent increase was higher for states 4 and 4+ than for state 3 respiration. Exposure of oyster mitochondria to 35 degrees C resulted in a decreased respiratory control and phosphorylation efficiency (P/O ratio) compared to that of the acclimation temperature (15 degrees C), while an intermediate temperature (25 degrees C) had no effect. Cadmium exposure did not lead to a significant volume change in oyster mitochondria in vitro. Low levels of cadmium (1-5 micromol l(-1)) stimulated the rate of proton leak in oyster mitochondria, while not affecting ADP-stimulated state 3 respiration. In contrast, higher cadmium levels (10-50 micromol l(-1)) had little or no effect on proton leak, but significantly inhibited state 3 respiration by 40-80% of the control rates. Elevated temperature increased sensitivity of oyster mitochondria to cadmium leading to an early inhibition of ADP-stimulated respiration and an onset of complete mitochondrial uncoupling at progressively lower cadmium concentrations with increasing temperature. Enhancement of cadmium effects by elevated temperatures suggests that oyster populations subjected to elevated temperatures due to seasonal warming or global climate change may become more susceptible to trace metal pollution, and vice versa.

Analysis of Variance↗
PubMedDate not supplied

[Body size and fecundity of Juxtafabia muliniarum (Brachyura: Pinnotheridae) associated with Saccostrea palmula (Bivalvia: Ostreidae), Costa Rica].

Size and fecundity observations of pea crab (Juxtafabia muliniarum) from the paleal cavity of the oyster Saccostrea palmula were made from May 1998 to May 1999. Infestation frequency was 18.52% in a sample of 540 oysters. Of 136 pea crabs, 36% were couples, 60% were single females and 4% were single males. The mean caparace length of J. muliniarum was 5.6 +/- 0.74 mm (range 4.0 to 7.6 mm) for females and 2.71 +/- 0.60 mm (range 1.6 to 4.0 mm) for males. The mean weight was 0.180 +/- 0.084 g (range 0.06 to 0.4 g) for females and 0.011 +/- 0.003 g (range 0.01 to 0.02 g) for males. Ovigerous females (43.75% of all females) were found in all months. The caparace length-fecundity relationship was F = 3904.6 Ln (Lc)--4651.1. The caparace length-weight relationship was P = 6 x 10(-4) Lc3.2122. The mean sex-ratio was 1.0 male: 2.4 females. Saccostrea palmula infected only by females was the dominant group (60.78%). This mollusk is a new host record for the crab.

Animals↗
PubMed2003

[Gonadic cycle of the American oyster Crassostrea virginica (Lamellibranchia: Ostreidae) in Mecoacán, Tabasco, México].

The American oyster Crassostrea virginica is exploited along Gulf of Mexico. This resource represents a job source and incomes for fishermen. In Mexico the production is supported by Tabasco state, the first producer. However, the mexican landings of this bivalve had been dropped about 40% last ten years. By 1999, Tabasco presents a unique ban season fishery of oysters. This season was based in evaluation of gonadal development by visual observations of color and texture, larvae and seeds abundance. In 2000, the government set up two ban seasons in terms of evaluation of populations every year, without gonadal analysis. In general, exists different spawning seasons for American oyster, in accordance with the environmental conditions. It is necessary to establish a ban season according to reproductive cycle. This study presents the gonadic cycle for an oyster population of Mecoacin lagoon along a year. It was defined five phases of the gonad development: resting, gametogenesis, mature or ripe, spawn and post spawn. Gametogenesis is present all the year, except December. The spawning activity was detected all year, except July and August. The ripe phase presented maximum values in August and December. It was proposed a modification of the ban seasons from April 15 - May 30, and September 15 - October 30 to March 15 - May 15 and September 1 - October 30, respectively, according to gonadic cycle obtained in this work. This modification would to avoid capture mature organisms (ready to spawn).

Animals↗
PubMed1983

[Electrophoretic study of gene-enzyme systems in oysters classified as Crassostrea gigas (Thunberg, 1793) and Crassostrea angulata (Lamarck, 1819) (Mollusca: Ostreidae)].

As a further contribution to the systematics of species belonging to the genus Crassostrea, electrophoretic studies of gene-enzyme system have been carried out on five populations of oysters regarded as either Crassostrea gigas or Crassostrea angulata species. Two populations of C. gigas from Japan (Karakawa and Hiroshima), one of C. gigas from France (Fouras), one of C. angulata from Portugal (Sado) and one of Crassostrea sp. from Italy (Chioggia) have been examined. The electrophoretic study of 20 enzyme loci and the genetic distance value showed no significant genetic divergence among the Crassostrea sp. populations. Thus the results of this study seem to confirm and extend to other populations what obtained by Buroker et al. (1979), that is a remarkable genetical identity between the two species Crassostrea gigas and Crassostrea angulata.

Animals↗
PubMed1996

[Rearing crassostrea gigas (Bivalvia:Ostreidae) in a semi-rigid net].

A culture system, consisting of a semi-rigid net, with an ABS frame filled with styrofoam was used for the culture of the Pacific oyster Crassostrea gigas, from 3.0 mm length seed. The culture system was tested in three locations, two inside San Quintín Bay and one in San Martín Island. The mean monthly growth was 8.69 mm and 8.96 mm in the Bay and 7.33 mm in San Martín Island. These growth rates show that this species can attain commercial sizes in 6 months, using the culture system tested.

Animals↗
PubMed2006

Combined effects of temperature acclimation and cadmium exposure on mitochondrial function in eastern oysters Crassostrea virginica gmelin (Bivalvia: Ostreidae).

Cadmium and temperature have strong impacts on the metabolic physiology of aquatic organisms. To analyze the combined impact of these two stressors on aerobic capacity, effects of Cd exposure (50 microg/L) on mitochondrial function were studied in oysters (Crassostrea virginica) acclimated to 12 and 20 degrees C in winter and to 20 and 28 degrees C in fall. Cadmium exposure had different effects on mitochondrial bioenergetics of oysters depending on the acclimation temperature. In oysters acclimated to 12 degrees C, Cd exposure resulted in elevated intrinsic rates of mitochondrial oxidation, whereas at 28 degrees C, a rapid and pronounced decrease of mitochondrial oxidative capacity was found in Cd-exposed oysters. At the intermediate acclimation temperature (20 degrees C), effects of Cd exposure on intrinsic rates of mitochondrial oxidation were negligible. Degree of coupling significantly decreased in mitochondria from 28 degrees C-acclimated oysters but not in that from 12 degrees C- or 20 degrees C-acclimated oysters. Acclimation at elevated temperatures also increased sensitivity of oyster mitochondria to extramitochondrial Cd. Variation in mitochondrial membrane potential explained 41% of the observed variation in mitochondrial adenosine triphosphate synthesis and proton leak between different acclimation groups of oysters. Temperature-dependent sensitivity of metabolic physiology to Cd has significant implications for toxicity testing and for extrapolation of laboratory studies to field populations of aquatic poikilotherms, indicating the importance of taking into account the thermal regime of the environment.

Acclimatization↗
PubMed2000

Evolution of parental care and ovulation behavior in oysters.

Approximately half of all living oysters brood offspring in the inhalant chamber of their mantle cavities; the remainder are broadcast spawners which do not engage in parental care of young. Ostreid ovulation involves a complex behavioral sequence that results in the countercurrent passage of newly spawned eggs through the gills (ctenidia) and into the inhalant chamber. We constructed molecular and combined-evidence phylogenetic trees to test hypotheses concerning the directionality of parental care evolution, and the evolutionary significance of the trans-ctenidial ovulation pathway, in the Ostreidae. Representatives of all three ostreid subfamilies, together with gryphaeid and nonostreoidean pterioid outgroups, were sequenced for a 941-nucleotide fragment of the 28S ribosomal gene. Our phylogenetic analyses indicate that (1) the Ostreidae are robustly monophyletic, (2) broadcast spawning and larval planktotrophy are ancestral ostreid traits, (3) trans-ctenidial ovulation predates the evolution of parental care in ostreid lineages, and (4) brooding originated once in the common ancestor of the Ostreinae/Lophinae, involved a modification of the final behavioral step in the ancestral ovulation pathway, and has been retained in all descendent lineages. Our data permit an independent test of fossil-based ostreid phylogenetic hypotheses and provide novel insights into oyster evolution and systematics.

Animals↗
PubMed2005

Specific detection of Pacific oyster (Crassostrea gigas) larvae in plankton samples using nested polymerase chain reaction.

Management of sustainable Pacific oyster fisheries would be assisted by an early, rapid, and accurate means of detecting their planktonic larvae. Reported here is an approach, based on polymerase chain reaction (PCR), for the detection of Pacific oyster larvae in plankton samples. Species-specific primers were designed by comparing partial mitochondrial cytochrome oxidase subunit I (COI) sequences from Crassostrea gigas, with other members of the family Ostreidae including those of Crassostrea angulata. Assay specificity was empirically validated through screening DNA samples obtained from several species of oysters. The assay was specific as only C. gigas samples returned PCR-positive results. A nested PCR approach could consistently detect 5 or more D-hinge-stage larvae spiked into a background of about 146 mg of plankton. The assay does not require prior sorting of larvae. We conclude that the assay could be used to screen environmental and ballast water samples, although further specificity testing against local bivalve species is recommended in new locations.

Animals↗
PubMed1999

The small-subunit rRNA gene sequences of venerids and the phylogeny of bivalvia.

The complete nucleotide sequence of the 18S subunit of ribosomal DNA (rDNA) was determined for the venerid clams Callista chione (Pitarinae) and Venus verrucosa (Venerinae). Comparison of the new sequences with the published sequences of 1 annelid, 2 gastropods, 2 polyplacophorans, and 19 bivalves showed that when the annelids are used as outgroup the gastropods diverge from the bivalves, which form a cluster including the polyplacophorans. When the gastropods alone were compared with the bivalves, the latter split in two groups corresponding to the two subclasses of Heterodonta and Pteriomorpha. The former include two taxa that diverged early, Galeomma and Tridacna, while the Veneridae and Mactridae form two sister groups. In contrast to previous reports and in line with morphological data, the Ostreidae are included in the Pteriomorphia and form a monophyletic group.

Animals↗
PubMed2005

5S rDNA and U2 snRNA are linked in the genome of Crassostrea angulata and Crassostrea gigas oysters: does the (CT)n.(GA)n microsatellite stabilize this novel linkage of large tandem arrays?

The 5S rRNA genes from 2 species of the Ostreidae family, Crassostrea angulata and Crassostrea gigas, were molecularly characterized. The genes were amplified, cloned, and sequenced. The results revealed a 5S rDNA tandem array with a nucleotide sequence in an inverted position within the nontranscribed spacer region that corresponded to the U2 small nuclear RNA (snRNA) gene. The sequence analysis indicated that both genes could be functionally active. The presence of the microsatellite (CT)n x (GA)n at the 3' end of both genes and the possible involvement of concerted evolution are discussed.

Animals↗
PubMed2005

[Carrying capacity of shellfish culture in Dadeng Island sea area of Xiamen].

To fully and rationally exploit local living marine resources while have a sustainable, efficient and healthy development of shellfish culture in the Dadeng Island sea area of Xiamen, this paper determined and analyzed the related model parameters of this area, including chlorophyll a, primary productivity, phytoplankton organic carbon tent, wild filter feeder yields in subtidal and intertidal zones and suspension culture area, cultured shellfish filtration rate and organic carbon content, shellfish's total weight to fresh meat ratio, and adopted the Nutrient namic Model and Coastal Waters' Energy Flow Analysis Model to estimate the ecological capacity of shellfish this area, from which, the wild filter feeder yields were deducted for estimating shellfish carrying capacity. model established by Fang Jianguang was also used to estimate the shellfish carrying capacity. Statistics analysis was used to estimate the suitable culture area of shellfish and other species, aiming at limiting local shellfish ture and optimizing the culture of various species mollusks. According to the estimation of the three models, shellfish carrying capacity in this area should be 35,248-39,990 tons, with an average of 37,488 tons, 140,008 x 10(4) - 158,850 x 10(4) individuals, averaging 148,903 x 10(4). The theoretically suitable culture area 2 145 hm2, 1,900 hm2 for Ostreidae, 81 hm2 for razor clam (Sinonovacula constricta), 20 hm2 for blood (Tegillarca granosa), and 144 hm2 for musculus (Musculus senhousei). In 2000, the actual culture area of shellfish and other species in the waters around Dadeng surpassed the estimated suitable culture area. It is proposed that some measures should be taken to reduce the overexploited area.

Animals↗
PubMed1983

Vibrio vulnificus septicemia. Isolation of organism from stool and demonstration of antibodies by indirect immunofluorescence.

Vibrio vulnificus was isolated from blood and stool cultures from a 65-year-old man who had underlying alcoholic liver disease. The patient had eaten raw oysters the day before he became ill. To our knowledge, this is the first published report of isolation of the organism from stool in a patient with primary septicemia, and it provides support for epidemiologic studies suggesting that the infection is acquired through the gastrointestinal tract by eating raw seafood containing the organism. It was also possible, in this case, to demonstrate the presence of high antibody titers to the blood isolate by indirect immunofluorescence but not by agglutinating or vibriocidal tests.

Aged↗
PubMed1995

An outbreak of Norwalk virus gastroenteritis associated with eating raw oysters. Implications for maintaining safe oyster beds.

OBJECTIVE: To determine the characteristics and the cause of an outbreak of gastroenteritis associated with eating raw oysters. DESIGN: Survey of groups of persons reporting illness to the health department after eating oysters; survey of convenience sample of oyster harvesters; and tracing of implicated oysters. SETTING: General community. MAIN OUTCOME MEASURES: Relative risk for illness after oyster consumption, source bed of contaminated oysters, presence of antibodies to Norwalk virus in serum, presence of a Norwalk virus in stool by direct electron microscopy and reverse transcription-polymerase chain reaction (RT-PCR), and DNA sequences of RT-PCR products. RESULTS: Seventy (83%) of 84 persons who ate raw oysters became ill vs three (7%) of 43 people who did not eat raw oysters (relative risk, 11.9; 95% confidence interval, 4.0 to 34.2). Eleven (79%) of 14 serum pairs had at least a fourfold increase in antibody to Norwalk virus. All 12 stool samples tested were positive by electron microscopy and/or RT-PCR for Norwalk virus. The RT-PCR products from all seven stool samples tested had identical DNA sequences. Implicated oysters were harvested November 9 through 13, 1993, from a remote oyster bed. Crews from 22 (85%) of 26 oyster harvesting boats working in this area reported routine overboard disposal of sewage. One harvester with a high level of antibodies to Norwalk virus reported having gastroenteritis November 7 through 10 and overboard disposal of feces into the oyster bed. CONCLUSIONS: This outbreak was caused by contamination of oysters in the oyster bed, probably by stool from one or more ill harvesters. Education of oyster harvesters and enforcement of regulations governing waste disposal by oyster harvesting boats might prevent similar outbreaks.

Adolescent↗
PubMed1975

Oyster-associated hepatitis. Failure of shellfish certification programs to prevent outbreaks.

During October and November 1973, outbreaks of hepatitis A associated with consumption of raw oysters occurred in Houston and in Calhoun, Ga. The oysters implicated in both outbreaks had been harvested in two Louisiana bays. Although the bays had been contaminated with polluted Mississippi River water two months before the oysters were harvested, at the time of harvesting the bays met national sanitation standards for shellfish growing and were certified for oyster fishing. These epidemics raise serious questions about the adequacy of shellfish sanitation monitoring systems currently in use.

Certification↗