Crassostrea Angulata Research Articles

Accumulation of metals and organochlorines in tissues of the oyster Crassostrea angulata from the Sado Estuary, Portugal

Sixty-eight composite samples of selected tissues (mantle, gills, adductor muscle and other soft parts) of Crassostrea angulata oysters collected in the upper Sado Estuary from May 1985 to May 1987 were analyzed for Fe, Mn, Zn, Cu, Cd, Pb, Ni, Cr, Co, PCB and total DDT. Principal component analysis demonstrated that Cd, Ni, Zn, Cu and Mn were more closely associated with mantle and gills, and their accumulation seemed to be highly influenced by oyster metabolic alterations. In contrast, partitioning of Pb and Cr in C. angulata tissues was largely related to environmental changes. As both biological and environmental factors tend to have major influences at the same period on the accumulation of PCB and DDT, the major factor defining their temporal partition in oysters from this upper estuary could not be clearly discerned. PCB and DDT were principally accumulated in the mantle and visceral mass.

Hepatitis a Virus Levels in Shellfish Exposed in a Natural Marine Environment to the Effluent from a Treated Sewage Outfall

Hepatitis A virus (HAV) contamination studies and cell-culturable virus determination were undertaken on oysters (Crassostrea angulata) and mussels (Mytilus edulis) kept for six months in the sea near the outfall of a sewage treatment plant. Shellfish and seawater samples were collected on 11 occasions at roughly 15-day intervals during this period. A radioimmunoassay revealed HAV contamination indices (P/N ≥ 2.1) in 3 oyster and 6 mussel samples and 1 sea-water sample. When a radiocompetition test was run on these samples, however, specificity was noted in one mussel sample only (P/N = 2.4). Immune electron microscopy showed that HAV particles were present in three effluent samples. Although a frequent demonstration at sometimes high concentrations (326.0 MPNCU/100 ml) in the effluent was observed, no cell-culturable virus were detected in both the shellfish and the seawater. Adenovirus alone were detected in one mussel sample, but not in the effluent. Complementary studies are now being conducted on all samples with an RIA HAV contamination index of P/N ≥ 2.1. The results of this investigation of viral contamination in a natural marine environment and our HAV detection assays underscore the difficulty of determining the true extent of these phenomena.

Molecular organization of paramyosin in the core of molluscan thick filaments

An arrangement of paramyosin molecules in the polar part of molluscan thick filaments is proposed which accounts for the X-ray diffraction pattern of the smooth adductor muscle (other than the part ascribed to actin) and for the appearance of separated filaments in the electron microscope. The proposed structure is based on the PI arrangement of Cohen et al. (1971), and contains sets of parallel, equidistant molecules with successive molecules displaced along the molecular axis by 72 nm, which we call PI sheets. Every molecule belongs to two PI sheets which are nearly perpendicular. This array is not propagated throughout the filament, but is sheared periodically in the direction of the molecular (filament) axis by 2 5 × 72 nm . The shear occurs along parallel equidistant planes which are inclined to the PI sheets. The analysis of the X-ray data has been made possible by concentrating on those patterns from filaments in which the two sets of PI sheets appear to be mutually perpendicular, a condition brought about by bathing the muscle in aqueous acetone. In one set, there are four intermoleeular spaces between shear planes (this appears to be true at least for the smooth adductors of Ostrea edulis, Crassostrea angulata and Mercenaria mercenaria). In the other set, the number varies with species and probably lies between eight and ten in the first two and appears to be six in the last named species. The known paracrystalline nature of paramyosin filaments suggests that this number, though dominant in one species. is not exactly constant.

Determination of meso-alanopine and D-strombine by high pressure liquid chromatography in extracts from marine invertebrates.

meso-Alanopine and D-strombine are separated by high pressure liquid chromatography using a cation exchange resin and 2.5 X 10(-5) M sulfuric acid as eluant, at a flow rate of 1.0 ml/min, 20 degrees C column temperature and a pressure of 4 500 kPa. Both opines were detected by conductivity. Separation and quantitation was possible in the range of 0.05 to 25 nmol of meso-alanopine and D-strombine. Chemically or enzymatically synthesized opines were quantitated using alanopine/strombine dehydrogenase from Crassostrea angulata. The enzyme was purified by ammonium sulfate precipitation, Sephadex G-100 filtration and fast-protein-liquid chromatography. Specific activity of the final preparation was 500 U/mg protein with glycine as substrate. The formation of meso-alanopine and D-strombine was demonstrated in neutralized perchloric acid extracts from muscle tissue of Arenicola marina L. following enhanced muscular activity and in Mytilus edulis L., Nucula nitida and Crassostrea angulata after 24 h of anoxia.

Structure of molluscan thick filaments: A common origin for diverse appearances

Thick filaments from the smooth adductor muscles of the oysters Ostrea edulis and Crassostrea angulata have been examined in the electron microscope after negative staining. The two well-known patterns of stain (whose origin and relation have been uncertain), one a series of transverse narrow lines at intervals of 144 Å along the filament axis and the other a regular two-dimensional arrangement of stained spots (Bear & Selby, 1956), are found to be mutually interconvertible by rotating the grid around the filament axis. This is interpreted to mean that the spots are the projections of stained regions running through the filament in a common direction. Only when looking along this direction will the net pattern be seen with maximum clarity and sharpness. On rotation of the filament round its axis, the spots broaden transversely to the axis, overlapping and ultimately only the axial periodicity will remain. The structure is therefore not helical, but resembles a crystal lattice, although no period can be discerned normal to the net plane. The addition of 10 m m-EDTA to all solutions used in the filament preparation (except the stain), especially when ammonium molybdate is the stain employed, removes many puzzling appearances (probably caused by positive staining) which render the interpretation difficult. The appearance of the negatively stained filament can be related to the stain patterns in negatively stained paramyosin paracrystals (Cohen et al., 1971).

Population genetics of the family ostreidae. I. Intraspecific studies of Crassostrea gigas and Saccostrea commercialis

The levels of genetic variation and estimates of genetic similarity and distance were determined for populations of Crassostrea gigas (Thunberg) and Saccostrea commercialis (Iredale and Roughley). The proportion of polymorphic loci in Japanese populations of C. gigas ranged from 0.58 to 0.63, while the individual heterozygosities ranged from 0.20 to 0.22. The proportion of polymorphic loci in Australian populations of S. commercialis ranged from 0.43 to 0.46, the individual heterozygosities from 0.17 to 0.19. The genetic similarity between different geographical populations of both species was approximately 99%. The genetic distance and similarity data derived from this investigation has resulted in some provisional reclassifications. The Portuguese oyster C. angulata (Lamarck) appears to be more appropriately regarded as a recent colonized isolate of C. gigas. The New Zealand oyster S. glomerata (Gould) is considered a subspecies of the eastern Australian rock oyster S. commercialis. The Japanese Kumamoto population of C. gigas warrants reclassification as the non-sibling species C. sikamea.

Phosphoglucose isomerase and esterase phenotypes in Crassostrea angulata and C. gigas

The phenotype distributions and the allele frequencies of the phosphoglucose isomerase and esterase loci examined in the samples of Crassostrea angulata (Essex, England) and C. gigas (Brittany) do not differ significantly and the two populations as such are indistinguishable. The validity of the species C. angulata is questioned and it is postulated that the two samples may be geographic isolates of the same species, i.e. C. gigas. The hatchery reared population of C. gigas from Conway is distinguishable from the other samples of Crassostrea examined. The lack of phenotype diversity is attributed to founder effects of the small parental stock imported in 1965. The distributions of all phenotypes are in agreement with Hardy-Weinberg expectations. Phosphoglucose isomerase (E.C. 5.3.1.9.) is a dimer governed by at least four alleles in C. angulata and five alleles in C. gigas. The slower ( Es-S) zone of the esterase electrophoretogram would appear, in both species to be governed by four alleles at a single locus. There was no esterase banding which was specific to either species of Crassostrea.

Phenotypes of phosphoglucose isomerase in some bivalve molluscs

1.1. Electrophoretic variants of phosphoglucose isomerase (E.C. 5.3.1.9) have been studied in six species of bivalve molluscs.2.2. Two phenotypes were observed in Ostrea edulis, three in Mytilus edulis, four in Crassostrea angulata, six in Ensis ensis, eleven in Tapes decussatus and twenty-five in Pecten maximus.3.3. The enzyme is inferred to be a dimer encoded at a single polymorphic locus in all species. There are two alleles at this locus in O. edulis and in M. edulis, four in C. angulata, three in E. ensis, five in T. decussatus and nine in P. maximus.4.4. The occurrence of enzyme polymorphisms in bivalve molluscs is discussed briefly.

SOME COMPARATIVE ASPECTS OF FILTER-FEEDING IN <italic>OSTREA EDULIS</italic> L. AND <italic>CRASSOSTREA ANGULATA</italic> (LAM.) (MOLLUSCA: BIVALVIA)

Journal Article SOME COMPARATIVE ASPECTS OF FILTER-FEEDING IN OSTREA EDULIS L. AND CRASSOSTREA ANGULATA (LAM.) (MOLLUSCA: BIVALVIA) Get access N. F. MATHERS N. F. MATHERS Department of Zoology, Chelsea College of Science and Technology, University of London Search for other works by this author on: Oxford Academic Google Scholar Journal of Molluscan Studies, Volume 41, Issue 2, August 1974, Pages 89–97, https://doi.org/10.1093/oxfordjournals.mollus.a065265 Published: 01 August 1974

The arrangement of myosin on the surface of paramyosin filaments in the white adductor muscle of Crassostrea angulata.

Observations of the surface of intact thick filaments from the oyster Crassostrea angulata have been made in the electron microscope. The surface structure has been revealed by metal shadowing and by a negative staining technique in which aqueous uranyl acetate solution is applied to filaments which have been rendered impervious to this solution. Both methods reveal a regular arrangement of round objects on the filament, interpreted as groups of myosin heads. The arrangement is that of the Bear-Selby net, probably with two or three myosin molecules per node. The possibility is discussed that the helical strands which give rise to the Bear-Selby net may occur in right- and left-handed forms in different filaments.

Portuguese and Japanese Oysters are the Same Species

Indistinguishable prodissoconch and adult shells, ease of hybridization, and normal meiosis and mitosis in the hybrids support the contention that the Portuguese oyster Crassostrea angulata and the Japanese oyster C. gigas are the same species. By rules of priority the Portuguese is a subspecies of the Japanese oyster. Two hypotheses are given to explain the widely disjunct distribution, by both species arising from a common ancestor or by undocumented introduction. Both oysters are of considerable commercial importance and crossing the two should result in progeny that can be selected for superior commercial traits.

Preliminary data on Crassostrea angulata Lam. in the Adriatic sea

Several small beds of the Portugese oyster ( Crassostrea angulata Lam.) were found on the bottom of a sea inlet in the Po river delta. In order to establish the possibilities of oyster culture there, a preliminary study of the growth and reproductive cycle of oysters kept in plastic trays from February, 1972 throughout March, 1973, was conducted. At monthly intervals (a) salinities and temperatures of the water, (b) mean growth and weight of 50 specimens and (c) histological data on the condition of the gonads, were recorded. The first results indicate that environmental conditions in the sea inlet are optimal for Crassostrea angulata and therefore that it would be a suitable place to develop the culture of oysters, before the complete disruption of the bottom by the undisciplined local fishermen takes place.

A comparative histochemical survey of enzymes associated with the processes of digestion in Ostrea edulis and Crassostrea angulata (Mollusca: Bivalvia)

No major differences in either concentration or location of enzymes were noted between the two species. An increase in enzyme production was noted in “fed” individuals–this being a direct response to the presence of food material. The gastric shield of both species was found to possess enzymic activity. The epithelium responsible for secretion of the crystalline style was also seen to secrete digestive enzymes which would be incorporated into the matrix of the style. Exopeptidases were identified in the walls of blood vessels and are attributed with the role of continued digestion of food material, prior to transport around the body. The mid‐gut contains a number of enzymes in high concentrations and serves a digestive as well as an absorptive role. Lipid is seen to be an important storage product, especially in the connective tissue surrounding the digestive diverticula.

L'ostréiculture dans la vallée de la Seudre

SUMMARY It appears to the layman's eye as a landscape of regular patches : « the claires ». The Valley of the Seudre produced 9500 tons of oysters in 1971 to 1600 in 1970. Oyster farming consists of several successive processes : The catch (gathering of the spats). The culture in oyster beds. The refinning carried out in « the claires » an exclusive process of the Basin of Marennes-Oleron. Oyster farming is closely linked to the natural elements. The oyster farmer's life must follow the rhythm of the tides. The population employed in the oyster industry reaches 1 1 500 people, 2719 of whom are grantees, more than 20 000 people live on that industry in the Marennes Area. For biological reasons, the oyster of Marennes has been superseded by the Portuguese oyster, which is in its turn, in harsh competition with the oyster of Japan since the mortality of 1970. As a consequence of the 1970-71 crisis, the turn-over of 1971-72 has dropped to 6 milliards A F.

The uptake and distribution of 65Zn in oysters

Over a period of 6 weeks in aquaria, Portuguese oysters Crassostrea angulata, accumulate 65Zn to a greater extent than do native Ostrea edulis, although intake rates for any particular organ in either species are quite similar. The general distribution pattern of radioactivity in the tissues is similar to that observed for stable zine and 65Zn in other oyster species, concentration occurring to the greatest extent in gills and mantle, and least in muscle. The observed equilibrium concentrations and biological half-lives are considerably less than those measured in the natural environment, and the significance of this and its bearing on the mechanism of uptake is discussed. Cobalt and iron depress the rate of 65Zn uptake by both oyster soft tissues and the shell. The limiting effect in soft tissues is probably due to competition for sites at the actual point of uptake. The distribution of 65Zn in tissue subcellular fractions separated by centrifugation shows the greatest concentration of the radioisotope in the insoluble tissue components of gills, mantle and heart. Appreciable amounts of 65Zn are associated with tissue proteins.

“Gill Disease” of Portuguese Oysters

DURING April and May of this year, there has been a heavy mortality of Portuguese oysters, Crassostrea angulata Lmk., which were imported into Britain from the River Tagus (Portugal) in March. Losses in some cases exceeded 90 per cent.

Electron microscope studies of the structure of the filaments in the opaque adductor muscle of the oyster Crassostrea angulata

The structure of the protein filaments in the contractile apparatus of the opaque adductor muscle of Crassostrea angulata has been studied in the electron microscope, mainly with thin-sectioning techniques. There are two types of filament in this contractile apparatus, thin actin filaments and thick paramyosin filaments. The paramyosin filaments, which can be up to 1500 Å thick, show a variety of band patterns in longitudinal section, and, occasionally, a layered structure in transverse section. In homogenized preparations, these thick filaments are cleaved into “ribbons” (Hall, Jakus & Schmitt, 1945), the thickness of which has been measured, and can be as little as 100 to 110 Å or even less. An equatorial X-ray reflexion at 120 Å is obtained from these and similar muscles when alive (Elliott & Lowy, 1961). All these observations are interpreted in terms of a paramyosin filament consisting of a stack of longitudinal lamellae, each with the paramyosin structure characteristic of this particular muscle (see the X-ray studies of Elliott, 1963) and stacked across the filament at intervals which are 120 Å in the living muscle. The variety of band patterns seen are explained in detail in terms of the various ways in which this stack may be sectioned.

Contraction in the opaque part of the adductor muscle of the oyster (Crassostrea angulata)

Contraction in the opaque part of the adductor muscle of the oyster (<i>Crassostrea angulata</i>)

Serological Studies of Species and Races in Oysters

Previous articleNext article No AccessSymposium on Immunogenetic Concepts in Marine Population ResearchSerological Studies of Species and Races in OystersKen-Ichi NumachiKen-Ichi Numachi Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 96, Number 889Jul. - Aug., 1962 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/282227 Views: 2Total views on this site Citations: 8Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Vanessa Simão Do Amaral, Luiz Ricardo L. Simone Revision of genus Crassostrea (Bivalvia: Ostreidae) of Brazil, Journal of the Marine Biological Association of the United Kingdom 94, no.44 (Feb 2014): 811–836.https://doi.org/10.1017/S0025315414000058Qi Wu, Fei Xu, Yongbo Bao, Li Li, Guofan Zhang Bindin Gene from the Kumamoto Oyster Crassostrea sikamea, and Divergence of the Fucose Lectin Repeats of Bindin among three Species of Crassostrea, Journal of Shellfish Research 30, no.11 (Apr 2011): 55–64.https://doi.org/10.2983/035.030.0109Futoshi Aranishi ., Yusuke Iidzuka . Multiplex PCR Diagnosis for Crassostrea Oyster Discrimination of C. sikamea and C. gigas, Journal of Fisheries and Aquatic Science 2, no.22 (Feb 2007): 173–177.https://doi.org/10.3923/jfas.2007.173.177D. Hedgecock THE CUPPED OYSTER AND THE PACIFIC OYSTER, (Jan 1995): 115–137.https://doi.org/10.1016/B978-012690685-1/50009-6Patrick M. Gaffney, Standish K. Allen Hybridization among Crassostrea species: a review, Aquaculture 116, no.11 (Sep 1993): 1–13.https://doi.org/10.1016/0044-8486(93)90217-MGary F. Newkirk Review of the genetics and the potential for selective breeding of commercially important bivalves, Aquaculture 19, no.33 (Mar 1980): 209–228.https://doi.org/10.1016/0044-8486(80)90045-9Muzammil Ahmed Speciation in Living Oysters, (Jan 1976): 357–397.https://doi.org/10.1016/S0065-2881(08)60283-7John E. Cushing The Blood Groups of Marine Animals, (Jan 1964): 85–131.https://doi.org/10.1016/S0065-2881(08)60031-0

The structure of the muscle fibres in the translucent part of the adductor of the oyster Crassostrea angulata

The arrangement of the protein filaments and other details of the ultrastructure of the con­tractile apparatus have been studied by methods which include the examination of thin sections in the electron microscope. The results help towards a better understanding of three general problems: the reasons why some muscles appear striated and others smooth; the mechanism of contraction in muscles which are not cross-striated; and the mechanism by which certain muscles of molluscs can maintain a high level of tension for long periods without fatigue. The filaments are of two kinds, thick paramyosin filaments, and much thinner filaments which very probably contain mainly actin. Both are short, relative to the length of the fibre, lie parallel to the fibre axis, and are grouped into separate arrays which alternate with each other along the length of the fibre. The arrays partly overlap, and in the regions of overlap each thick filament is surrounded by twelve thin ones, and each thin filament is usually ‘shared' by two thick ones. The regions of the fibre where the arrays of thin filaments are exposed are identified as I -bands, the intervening regions (arrays of paramyosin filaments partly over­-lapping with arrays of thin filaments) as A -bands. The relative positions of the arrays change with the length of the muscle: the extent of overlap in the A -bands increases as the muscle shortens and decreases on stretching. Thus the muscle shortens by a sliding filament mechanism. Although the muscle is identified as a striated muscle because it has A - and I -bands, it differs from cross -striated muscles in two respects. In the first place, the bands lie at a small angle (about 10°) to the fibre axis, and are arranged helically around the outer part of the fibre, giving rise to the ‘double-oblique striation’ visible in the light microscope; more­ over, the bands branch and anastomose with each other in the core of the fibre. In the second place, there are no Z -lines, but in the planes where Z -lines would be expected, discrete dense-bodies are present. Similar dense-bodies occur in many smooth muscles, for example, in the mammalian uterus (Mark 1956; Shoenberg 1958), and in the anterior byssus retractor of Mytilus (Hanson &amp; Lowy 1959 a ). The contractile apparatus of the latter closely resembles that of the oyster muscle in many respects, but the filaments are not clearly grouped into separate arrays. This feature, the presence or absence of segregated arrays of filaments, could serve as the main criterion for distinguishing striated from smooth muscles. Where the arrays of thick and thin filaments overlap in the A -bands, the two kinds of filaments appear to be cross-linked by means of transverse projections which belong to the thick filaments. The view is put forward that the paramyosin filaments are comparable to the myosin-containing filaments of the cross-striated muscles of vertebrates, and that the cross-links in the oyster muscle are comparable to actin-myosin links. The role which paramyosin filaments play in the mechanism by which certain muscles of molluscs maintain tension very economically is also discussed. The results described in this paper support the hypothesis (Lowy &amp; Millman 1959 b , 1960) that tension is held by cross-links in a sliding filament contractile mechanism and that the economy of the system is due to a low rate of detachment of these cross-links. The alternative ‘catch’-mechanism hypothesis (Johnson, Kahn &amp; Szent-Györgyi 1959; Johnson &amp; Szent-Györgyi 1959; Rüegg 1959) which supposes that tension is maintained by some change of state of the protein within a paramyosin system, is difficult to reconcile with the present findings. Structures which resemble the ‘dyads’ of the cross-striated muscles of vertebrates have been found beneath the cell membrane. Their possible function in the intracellular trans­mission of stimuli is discussed in view of the fact that the fibres of the oyster muscle are only about 2 μ thick.