Science.gov

Sample records for cockle cerastodema edule

  1. A bedload transport equation for the Cerastoderma edule cockle

    NASA Astrophysics Data System (ADS)

    Anta, Jose; Peña, Enrique; Puertas, Jerónimo; Cea, Luis

    2013-02-01

    Hydrodynamics play an important role in the structure of many marine ecosystems of bivalves. After severe storm periods, large amounts of the Cerastoderma edule stocks were transported from the Lombos do Ulla shellfish bed (Spain). This paper presents the results of laboratory experiments carried out to analyze the bedload transport of this bivalve emulating the stormy shellfish bed conditions. Flow velocities were measured using particle image velocimetry and the double averaged methodology was applied to determine the main flow characteristics over different cockle patches. The flow structure exhibits properties of skimming and isolated flows depending on the density of bivalves. Bed shear stress was determined from the log-law and the cockles were geometrically characterized in order to derive specific bedload transport equations in a conventional deterministic sediment transport framework. The obtained formulas can be implemented in common numerical codes to further analyze mollusk stability, bedload transport and dispersal in their aquatic systems.

  2. Assessing parasite community structure in cockles Cerastoderma edule at various spatio-temporal scales

    NASA Astrophysics Data System (ADS)

    de Montaudouin, Xavier; Binias, Cindy; Lassalle, Géraldine

    2012-09-01

    Cockles (Cerastoderma edule) are among the most exploited bivalves in Europe. They live in lagoons and estuaries where they undergo many stressors including parasites. Trematodes are the most prevalent macroparasites of cockles and can exert a significant impact on their host populations depending on parasite species and infection intensity. Monitoring these parasite-host systems in order to predict potential host mortalities require a correct knowledge of the spatio-temporal variation of infection. A yearly monitoring of cockles from six stations around Ile aux Oiseaux, Arcachon Bay (France) was conducted between 1998 and 2005. Distance between two stations was ca. 1 km. Nine trematode species were identified. Despite a relative homogeneity of the parasite community structure in cockles, between three and six clusters were identified by Hierarchical Ascendant Classification showing that among-sites heterogeneity of trematode communities in cockles was higher than within-site heterogeneity. At the scale of 8 years, and for 2-year old cockles, these patterns remained stable in four out of six stations. Spatial aggregation disappeared with cockle age, since parasite communities in 3-year cockles did not reflect any particular station(s): with age, cockles eventually accumulated most trematode species and lost the site signature. On the other hand, we demonstrated that the commonly accepted theory stating that older/larger cockles accumulate more trematode larvae was not verified and that there could exist a vulnerable age/size that doesn't correspond to largest values. This study provided a new insight in the parasite community heterogeneity in their host, and in the significance of samples in relation with space and time.

  3. Bivalve vulnerability is enhanced by parasites through the deficit of metallothionein synthesis: A field monitoring on cockles (Cerastoderma edule)

    NASA Astrophysics Data System (ADS)

    Baudrimont, M.; de Montaudouin, X.; Palvadeau, A.

    2003-05-01

    The effect of the parasite Labratrema minimus (digenean trematode) on metallothioneins (MTs) biosynthesis by the cockle Cerastoderma edule (bivalve) was investigated. An in situ monitoring allowed to describe and compare monthly variations of MTs concentrations in cockles with and without L. minimus in a site free of metai pollution (Banc d'Arguin, Arcachon Bay, France). These concentrations are correlated with the reproductive cycle of the bivalve: (I) in spent cockles, MTs concentrations are higher in infected cockles. probably due to host tissue lysis: (2) during maturation, MTs biosynthesis increases in all cockles. However, concentrations are lower in parasitized individuals in relation with castration by parasites. Therefore, parasite infection in cockles, which can affect 100% of individuals, may contribute to a higher vulnerability of organisms to metal contamination.

  4. Perkinsus chesapeaki observed in a new host, the European common edible cockle Cerastoderma edule, in the Spanish Mediterranean coast.

    PubMed

    Carrasco, N; Rojas, M; Aceituno, P; Andree, K B; Lacuesta, B; Furones, M D

    2014-03-01

    Histological observations showed the presence of a Perkinsus sp. parasite in Cerastoderma edule tissues for the first time in the Spanish Mediterranean coast. ITS molecular characterization by PCR-RFLP, in situ hybridization and sequencing, identified the parasite as Perkinsus chesapeaki, with a maximum identity of 99-100% with GenBank P. chesapeaki sequences from France and 97% with P. chesapeaki sequences of North American origin when BLAST analysis was carried out. Furthermore, phylogenetic studies placed the European cockle parasite in a well defined cluster together with the other European isolates. This is the first report of P. chesapeaki in the cockle C. edule. PMID:24525498

  5. Occurrence and role of a Quaternary base, trimethylamine oxide, in two cockle species, Cerastoderma edule and Cerastoderma lamarcki

    NASA Astrophysics Data System (ADS)

    de Vooys, C. G. N.

    2002-02-01

    Trimethylamine oxide was demonstrated in the tissues of two European cockle species: Cerastoderma edule and Cerastoderma lamarcki (Mollusca: Bivalvia). No role in osmoregulation could be demonstrated, but a passive accumulation of the compound was found. Trimethylamine was demonstrated to be present in phytoplankton. Passive changes of the concentration of trimethylamine oxide are likely to occur in cockle tissues depending on the concentration of trimethylamine in the food.

  6. Genetic diversity and population differentiation in the cockle Cerastoderma edule estimated by microsatellite markers

    NASA Astrophysics Data System (ADS)

    Martínez, L.; Méndez, J.; Insua, A.; Arias-Pérez, A.; Freire, R.

    2013-03-01

    The edible cockle Cerastoderma edule is a marine bivalve commercially fished in several European countries that have lately suffered a significant decrease in production. Despite its commercial importance, genetic studies in this species are scarce. In this work, genetic diversity and population differentiation of C. edule has been assessed using 11 microsatellite markers in eight locations from the European Atlantic coast. All localities showed similar observed and expected heterozygosity values, but displayed differences in allelic richness, with lowest values obtained for localities situated farther north. Global Fst value revealed the existence of significant genetic structure; all but one locality from the Iberian Peninsula were genetically homogeneous, while more remote localities from France, The Netherlands, and Scotland were significantly different from all other localities. A combined effect of isolation by distance and the existence of barriers that limit gene flow may explain the differentiation observed.

  7. Trematode communities in cockles (Cerastoderma edule) of the Ria de Aveiro (Portugal): influence of inorganic contamination.

    PubMed

    Freitas, R; Martins, R; Campino, B; Figueira, E; Soares, A M V M; Montaudouin, X

    2014-05-15

    This work aims to assess the trematode parasites infecting the edible cockle Cerastoderma edule, collected in the Ria de Aveiro lagoon, one of the most relevant biodiversity hotspots of the Western Iberia, and evaluate the relationship between the observed patterns and environmental descriptors. A total of 11 of the 16 trematode species known to infect C. edule were identified, including Himasthla continua and Psilostomum brevicolle as new occurrences in this lagoon. Parvatrema minutum was the most abundant and dominant species. Species richness and prevalence were high. The relationship between trematode species abundance, intensity and prevalence, and also environmental variables, showed that most parasites preferred muddy sand areas with euhaline conditions in opposition to areas with contamination and/or distant from the lagoon entrance. This study highlighted the good ecological status of the ecosystem and the transitional biogeographic characteristics of the western Portuguese coast where northern and subtropical faunas can coexist. PMID:24680719

  8. Detection of Infectious Cryptosporidium parvum Oocysts in Mussels (Mytilus galloprovincialis) and Cockles (Cerastoderma edule)

    PubMed Central

    Gomez-Bautista, M.; Ortega-Mora, L. M.; Tabares, E.; Lopez-Rodas, V.; Costas, E.

    2000-01-01

    Infective Cryptosporidium parvum oocysts were detected in mussels (Mytilus galloprovincialis) and cockles (Cerastoderma edule) from a shellfish-producing region (Gallaecia, northwest Spain, bounded by the Atlantic Ocean) that accounts for the majority of European shellfish production. Shellfish were collected from bay sites with different degrees of organic pollution. Shellfish harboring C. parvum oocysts were recovered only from areas located near the mouths of rivers with a high density of grazing ruminants on their banks. An approximation of the parasite load of shellfish collected in positive sites indicated that each shellfish transported more than 103 oocysts. Recovered oocysts were infectious for neonatal mice, and PCR-restriction fragment length polymorphism analysis demonstrated a profile similar to that described for genotype C or 2 of the parasite. These results demonstrate that mussels and cockles could act as a reservoir of C. parvum infection for humans. Moreover, estuarine shellfish could be used as an indicator of river water contamination. PMID:10788352

  9. Disseminated neoplasia causes changes in ploidy and apoptosis frequency in cockles Cerastoderma edule.

    PubMed

    Díaz, S; Villalba, A; Insua, A; Soudant, P; Fernández-Tajes, J; Méndez, J; Carballal, M J

    2013-07-01

    A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence in some cockle Cerastoderma edule beds of Galicia (NW Spain). Chromosome counts, examination of chromosome morphology, DNA quantification by flow cytometry and estimation of apoptosis frequency by TUNEL assay and flow cytometry were performed in cockles with different DN severity. Metaphases obtained from gills of DN-affected cockles displayed a chromosome number ranging from 41 to 145, while normal number is 38; changes in chromosome morphology were also evident, with numerous microchromosomes occurring. Haemolymph flow cytometry analysis revealed difference in DNA content between healthy and DN-affected cockles. Aneuploid peaks ranged from 1.3n to 8.9n. Apoptosis frequency was determined on histological sections (TUNEL assay) and haemolymph samples (flow cytometry). Both techniques revealed neoplastic cells in apoptosis. The higher DN severity, the lower the percentage of apoptotic cells. According to flow cytometry results, the negative association between DN severity and apoptosis frequency only affected the neoplastic cells, whereas DN did not significantly affect the percentage of apoptotic hyalinocytes or apoptotic granulocytes. PMID:23583807

  10. Mass mortalities in bivalve populations: A review of the edible cockle Cerastoderma edule (L.)

    NASA Astrophysics Data System (ADS)

    Burdon, Daryl; Callaway, Ruth; Elliott, Michael; Smith, Tim; Wither, Andrew

    2014-10-01

    Mass mortalities in bivalve populations have long been of particular concern, especially when the species supports a commercial fishery or is of conservation interest. Here we consider the evidence of mass mortalities of the edible cockle, Cerastoderma edule (L.). Through the construction of a conceptual model eight potential factors (or groups of factors) which may cause mass mortalities are identified and reviewed. These include: food limitation; density; oxygen depletion and organic loadings; temperature and salinity; parasites, pathogens and commensals; toxicants and other persistent pollutants; predation, and changes in sediment, suspended solids, topography and bathymetry. The interplay between factors in recognized and discussed based on evidence mainly from the published literature relating to temperate edible cockle beds. Anecdotal evidence is also reported from a structured survey of site-specific evidence provided by fisheries managers in England and Wales. Case studies from the UK and Europe indicate that there is often no single, clear generic cause of mass mortalities in cockle populations. The importance of linked site-specific scientific investigations and laboratory-based experiments to fill the gaps in our current understanding of mass mortalities in bivalve species is highlighted as necessary to take account of both local extrinsic and intrinsic factors.

  11. The interactive roles of predation and tidal elevation in structuring populations of the edible cockle, Cerastoderma edule

    NASA Astrophysics Data System (ADS)

    Sanchez-Salazar, M. E.; Griffiths, C. L.; Seed, R.

    1987-08-01

    The size and age structure of the Cerastoderma edule population at Traeth Melynog, North Wales, varies dramatically with tidal level. In areas low on the shore up to 96% of cockle spat fail to survive their first summer, but mortality rate subsequently declines and remains at a low level. By contrast cockles high on the shore suffer moderate mortality during their first year (47%), but increasing rates thereafter. High-shore populations consequently consist mainly of smaller (younger) individuals and low-shore ones of a transient spatfall, plus a few larger and older individuals. The potential role of shore crabs, Carcinus maenas, and oystercatchers, Haematopus ostralegus in the determination of these patterns is assessed. Shore crabs move up into the intertidal to feed with each flood tide from about April to December. They selectively consume cockles < 15 mm in length, taking an estimated 236 × 10 3 cockles, or 2432 g dry flesh year -1 per linear meter of shoreline, mostly from lower shore levels. Oystercatchers are present only during winter and preferentially select large cockles of at least 20 mm length. They are estimated to remove 9 × 10 3 cockles, or 1204 g dry flesh year -1 per linear meter of shoreline, most of this from mid- and high-shore levels. These results indicate that shore crabs are far more important predators than previously suspected, taking 25 × the numbers and 2 × the biomass cosumed by oystercatchers. Predation also appears to be the key factor controlling the structure of the C. edule population. Crabs consume almost all the cockles settling low on the shore during their first summer, but avoid older individuals, which subsequently survive and grow well under low levels of oystercatcher predation. On the high shore, crabs are unimportant and the cockles survive well as they slowly grow into the size range attractive to oystercatchers. Thereafter they suffer increasingly severe winter mortality and are soon eliminated.

  12. Factors involved in growth plasticity of cockles Cerastoderma edule (L.), identified by field survey and transplant experiments

    NASA Astrophysics Data System (ADS)

    De Montaudouin, Xavier

    1996-12-01

    In Arcachon Bay, a macrotidal coastal lagoon in southwest France, growth rates of cockles Cerastoderma edule (L.) differ greatly between locations. Sampling of populations at different tidal levels showed that the mean shell length was significantly and positively correlated with immersion time, whereas no correlation was found with population density and microphytobenthos biomass. Transplants of cockles between two intertidal sites were used to examine the relative importance of habitat and site of origin for growth rate and condition index. Artifacts due to manipulation were assessed, i.e. the impact of enclosures on growth, conditon index and mortality. During a 5-mo reciprocal transplant experiment, growth rates of the transplanted cockles and the cockles already present were similar, whereas the sites of origin did not affect growth rate. Condition index, however, displayed significant differences in relation to both transplant and origin sites. During a further 6-mo experiment in which cockles were transplanted from one site to four new sites, growth was mainly influenced by tidal level. These results indicate that net growth started when cockles were immersed 30% of the time. It is concluded that, on the scale of Arcachon Bay (156 km 2), differences in growth and condition between cockle populations are largely phenotypic. Tidal level ( i.e. food supply and emersion stress) accounts for most of these differences, but the existence of genetically or physiologically different populations cannot be excluded.

  13. Mercury bioaccumulation and decontamination kinetics in the edible cockle Cerastoderma edule.

    PubMed

    Cardoso, P G; Grilo, T F; Pereira, E; Duarte, A C; Pardal, M A

    2013-02-01

    Mercury bioaccumulation and decontamination kinetics in the edible cockle Cerastoderma edule were studied through a mesocosms experiment after a medium-term exposure to the metal. The results revealed that the bivalve presented distinct bioaccumulation kinetics according to the different tissues. While the gills showed a linear accumulation pattern, the digestive gland and the entire organism presented a saturation model, with higher accumulation during the first 7d of exposure and lower during the rest of the time. In addition, the bioaccumulation rate was not proportional to the Hg concentration, since the organisms under lower contamination presented higher bioconcentration factors than the ones under higher contamination. Gills were the tissues with higher mercury accumulation capability. Concerning the decontamination phase, C. edule lost approximately 80% of the mercury after 24h exposure in clean seawater. Nevertheless, never reached the original condition, showing in the final (20 d detox), Hg levels (>0.5 ppm) higher than those allowed by the legislation regulating human food consumption. This represents a matter of concern for Human health. PMID:23141557

  14. Trace element fingerprinting of cockle (Cerastoderma edule) shells can reveal harvesting location in adjacent areas.

    PubMed

    Ricardo, Fernando; Génio, Luciana; Costa Leal, Miguel; Albuquerque, Rui; Queiroga, Henrique; Rosa, Rui; Calado, Ricardo

    2015-01-01

    Determining seafood geographic origin is critical for controlling its quality and safeguarding the interest of consumers. Here, we use trace element fingerprinting (TEF) of bivalve shells to discriminate the geographic origin of specimens. Barium (Ba), manganese (Mn), magnesium (Mg), strontium (Sr) and lead (Pb) were quantified in cockle shells (Cerastoderma edule) captured with two fishing methods (by hand and by hand-raking) and from five adjacent fishing locations within an estuarine system (Ria de Aveiro, Portugal). Results suggest no differences in TEF of cockle shells captured by hand or by hand-raking, thus confirming that metal rakes do not act as a potential source of metal contamination that could somehow bias TEF results. In contrast, significant differences were recorded among locations for all trace elements analysed. A Canonical Analysis of Principal Coordinates (CAP) revealed that 92% of the samples could be successfully classified according to their fishing location using TEF. We show that TEF can be an accurate, fast and reliable method to determine the geographic origin of bivalves, even among locations separated less than 1 km apart within the same estuarine system. Nonetheless, follow up studies are needed to determine if TEF can reliably discriminate between bivalves originating from different ecosystems. PMID:26149418

  15. Biomarkers and transcription levels of cancer-related genes in cockles Cerastoderma edule from Galicia (NW Spain) with disseminated neoplasia.

    PubMed

    Ruiz, Pamela; Díaz, Seila; Orbea, Amaia; Carballal, Maria J; Villalba, Antonio; Cajaraville, Miren P

    2013-07-15

    Disseminated neoplasia (DN) is a pathological condition reported for several species of marine bivalves throughout the world, but its aetiology has not yet been satisfactorily explained. It has been suggested that chemical contamination could be a factor contributing to neoplasia. The aim of the present study was to compare cell and tissue biomarkers and the transcription level of cancer-related genes in cockles (Cerastoderma edule) affected by DN with those of healthy cockles in relation to chemical contaminant burdens. For this, cockles were collected from a natural bed in Cambados (Ria de Arousa, Galicia) in May 2009. The prevalence of DN was 12.36% and 3 degrees of DN severity were distinguished. No significant differences in metal accumulation, non-specific inflammatory responses and parasites were observed between healthy and DN-affected cockles. Lysosomal membrane stability was significantly reduced in cockles affected by DN, which indicates a poorer health condition. Very low frequencies of micronuclei were recorded and no significant differences were detected between DN severity groups. Haemolymph analyses showed a higher frequency of mitotic figures and binucleated cells in cockles affected by moderate and heavy DN than in healthy ones. Neoplastic animals showed significantly higher transcription levels of p53 and ras than healthy cockles and mutational alterations in ras gene sequence were detected. Low concentrations of metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls and phthalate esters were measured in cockles from Cambados. In conclusion, cockles affected by DN suffer a general stress situation and have altered patterns of cancer-related gene transcription. Further studies are in progress to elucidate mechanisms of carcinogenesis in this species. PMID:23665240

  16. Post-larval and juvenile mortality in a population of the edible cockle cerastoderma edule (L.) from northern Brittany

    NASA Astrophysics Data System (ADS)

    Guillou, J.; Tartu, C.

    Survival and growth of newly settled cockles Cerastoderma edule in an intertidal population in the Bay of Moriaix (northern Brittany) were followed from 1987 to 1991. The main settlement occurred throughout the autumn. After high post-larval mortality, the densities of juveniles became stabilized in late autumn or early winter. A fresh mortality period started in winter and continued during spring parallel with an acceleration in growth. The mortality rate declined to zero or near-zero values by early summer, at which time individuals had reached a length of 10 to 12 mm. Several hypotheses concerning the causes of mortality during these periods are discussed.

  17. Growth of cockles ( Cerastoderma edule) in the Oosterschelde described by a Dynamic Energy Budget model

    NASA Astrophysics Data System (ADS)

    Wijsman, Johannes W. M.; Smaal, Aad C.

    2011-11-01

    A Dynamic Energy Budget (DEB) model for cockles is presented and calibrated using detailed data on cockle growth and water quality in the Oosterschelde. Cockles in the intertidal areas of the Oosterschelde have an important function as a food source for wading birds and as such for the natural values of the ecosystem. In the presented model, special attention is paid to the formulation and parameter estimation of the functional response. With this functional response, the food quantity and quality variables such as Chlorophyll- a, POM, POC and TPM are translated into food ingestion rate for the cockles. The calibration of the specific parameters included in this functional response is done using a detailed, long term dataset (1992-2007) of cockle growth in the Oosterschelde estuary. This dataset gives a good overview of the development of the cockle population in relation to the environmental conditions (food availability and ambient temperature). The DEB model was able to describe the spatial variation in cockle growth in the Oosterschelde as a function of environmental conditions and the parameters of the functional response. Both the data and the model show that growth performance of cockles is highest in the western and central part of the Oosterschelde due to the higher concentrations of Chlorophyll- a, which is an important food source for cockles. The model failed to describe the large variation in ash-free dry weight during the season. It is tested whether this is caused by aggregating the data by running the model for the full life cycle of year class 2001 at a specific location in the western part of the Oosterschelde. Finally, the model simulations have been compared to growth simulations obtained with an existing ecophysiological model for cockles in the Oosterschelde, the COCO model, with identical forcing. The COCO model showed higher growth in terms of shell length compared to the DEB model and the field observations.

  18. Metazoan parasites in intertidal cockles Cerastoderma edule from the northern Wadden Sea

    NASA Astrophysics Data System (ADS)

    Thieltges, David W.; Reise, Karsten

    2006-11-01

    At four intertidal sites near the island of Sylt (eastern North Sea), 13 metazoan parasite taxa were found in 1400 cockles investigated, with digenean trematodes being dominant. Almost all cockles were infected by parasites and most individuals harboured more than one parasite species. We observed four conspicuous patterns: (1) Adult cockles harboured a two times higher species richness (2003: 6.1 ± 0.7 species/host; 2004: 7.1 ± 0.7) than juveniles (2003: 2.9 ± 0.8; 2004: 3.4 ± 0.8) and total parasite community composition significantly differed between age groups. (2) Infection levels were 2-52 times higher in adult cockles than in juveniles both in trematode species and in non-trematode species. In the dominant trematodes, species utilising cockles as first intermediate host ( Gymnophallus choledochus, Labratrema minimus, Monorchis parvus) only occurred in adult cockles, and prevalences were low (2-12%). Prevalences of up to 100% were reached by trematodes using cockles as second intermediate host ( Himasthla elongata, H. continua, H. interrupta, Renicola roscovita, Psilostomum brevicolle, Meiogymnophallus minutus, Gymnophallus gibberosus). Metacercariae of these species were segregated between body parts within cockles. (3) High spatial heterogeneity in parasite community composition and infection levels occurred between sampling sites. However, communities in juveniles were more similar than communities in adults. (4) Temporal variation in parasite community composition was low between two consecutive years, especially for adult cockles. The omnipresence of parasites in this dominant bivalve species has important implications for sampling designs and as a potentially confounding variable in e.g. physiological studies. It suggests strong and cumulative negative effects on the cockle hosts.

  19. Potential use of fatty acid profiles of the adductor muscle of cockles (Cerastoderma edule) for traceability of collection site

    PubMed Central

    Ricardo, Fernando; Pimentel, Tânia; Moreira, Ana S. P.; Rey, Felisa; Coimbra, Manuel A.; Rosário Domingues, M.; Domingues, Pedro; Costa Leal, Miguel; Calado, Ricardo

    2015-01-01

    Geographic traceability of seafood is key for controlling its quality and safeguarding consumers’ interest. The present study assessed if the fatty acid (FA) profile of the adductor muscle (AM) of fresh cockles (Cerastoderma edule) can be used to discriminate the origin of specimens collected in different bivalve capture/production areas legally defined within a coastal lagoon. Results suggest that this biochemical approach holds the potential to trace sampling locations with a spatial resolution <10 Km, even for areas with identical classification for bivalve production. Cockles further away from the inlet, i.e. in areas exposed to a higher saline variation, exhibited lower levels of saturated fatty acids, which are key for stabilizing the bilayer structure of cell membranes, and a higher percentage of polyunsaturated fatty acids, which enhance bilayer fluidity. Results suggest that the structural nature of the lipids present in the AM provides a stable fatty acid signature and holds potential for tracing the origin of bivalves to their capture/production areas. PMID:26084395

  20. Ingestion and absorption of particles derived from different macrophyta in the cockle Cerastoderma edule: effects of food ration.

    PubMed

    Arambalza, U; Ibarrola, I; Navarro, E; Urrutia, M B

    2014-02-01

    We analyzed the capacity of the common cockle Cerastoderma edule to utilize detrital food particles obtained from three different macrophytes: the vascular plant Juncus maritimus and two green macroalgae (Ulva lactuca and Enteromorpha sp.). We measured feeding and digestive parameters at three concentrations of detritus (0.5, 1.0 and 3.0 mm(3) l(-1)), so that functional relationships between ingestive and digestive processes could be assessed. Increasing concentrations of detritus (food) resulted in a reduction in filtering activity (clearance rate l h(-1)), but an increase in ingestion rate. Consequently, gut content also increased with increasing food concentration, irrespective of food type. In contrast, the trend followed by absorption efficiency with increasing ingestion rate was determined by food type, being significantly reduced (from 0.63 to 0.11) with Juncus but remaining almost constant with the green macroalgae (0.58 ± 0.07 with Ulva) or only minimally reduced (from 0.66 to 0.48 with Enteromorpha). This differential response had clear consequences for energy uptake: absorption rate increased with increasing particulate organic matter with Enteromorpha but decreased with Juncus. We discuss the possible role of digestive parameters such as digestibility, gut content and gut-residence time in the differential utilization of detrital matter from different vegetal origins by cockles. PMID:24178188

  1. Potential use of fatty acid profiles of the adductor muscle of cockles (Cerastoderma edule) for traceability of collection site.

    PubMed

    Ricardo, Fernando; Pimentel, Tânia; Moreira, Ana S P; Rey, Felisa; Coimbra, Manuel A; Rosário Domingues, M; Domingues, Pedro; Costa Leal, Miguel; Calado, Ricardo

    2015-01-01

    Geographic traceability of seafood is key for controlling its quality and safeguarding consumers' interest. The present study assessed if the fatty acid (FA) profile of the adductor muscle (AM) of fresh cockles (Cerastoderma edule) can be used to discriminate the origin of specimens collected in different bivalve capture/production areas legally defined within a coastal lagoon. Results suggest that this biochemical approach holds the potential to trace sampling locations with a spatial resolution <10 Km, even for areas with identical classification for bivalve production. Cockles further away from the inlet, i.e. in areas exposed to a higher saline variation, exhibited lower levels of saturated fatty acids, which are key for stabilizing the bilayer structure of cell membranes, and a higher percentage of polyunsaturated fatty acids, which enhance bilayer fluidity. Results suggest that the structural nature of the lipids present in the AM provides a stable fatty acid signature and holds potential for tracing the origin of bivalves to their capture/production areas. PMID:26084395

  2. Physiological responses of the European cockle Cerastoderma edule (Bivalvia: Cardidae) as indicators of coastal lagoon pollution.

    PubMed

    Nilin, Jeamylle; Pestana, João Luís Teixeira; Ferreira, Nuno Gonçalo; Loureiro, Susana; Costa-Lotufo, Letícia Veras; Soares, Amadeu M V M

    2012-10-01

    Physiological responses can be used as effective parameters to identify environmentally stressful conditions. In this study, physiology changes such as oxygen consumption, clearance rate, survival in air, condition index and energy reserves were measured on natural populations of cockles collected from different sites at Ria de Aveiro, Portugal. At those sites, sediment samples were collected for Hg concentration analysis. Cockles were used for the evaluation of both the Hg concentration and physiological response. Mercury was detected in the cockle tissue and in the sediment collected from the sampling points both nearby and distant from the main mercury contamination source. The energy content was negatively correlated with both Hg concentration in cockle tissues and survival in air. Nonetheless, the energy content was positively correlated with the condition index, and there was a positive correlation between the survival in air test and the tissue mercury concentration. A PCA-factor analysis explained 86.8% of the total variance. The principal factor (62.7%) consisted of the air survival, the Hg in soft tissues (positive) and the condition index (negative). The second factor (24.1%) consisted of a negative correlation between the oxygen consumption and the clearance rate. Due to their sensitivity to environmental conditions, the physiological responses of cockles can be used to assess the ecological status of aquatic environments. More effort should be invested in investigating the effects of environmental perturbations on cockle health once they are a good reporter organism. PMID:22846762

  3. A preliminary threshold model of parasitism in the Cockle Cerastoderma edule using delayed exchange of stability

    NASA Astrophysics Data System (ADS)

    O'Grady, E. A.; Culloty, S. C.; Kelly, T. C.; O'Callaghan, M. J. A.; Rachinskii, D.

    2015-02-01

    Thresholds occur, and play an important role, in the dynamics of many biological communities. In this paper, we model a persistence type threshold which has been shown experimentally to exist in hyperparasitised flukes in the cockle, a shellfish. Our model consists of a periodically driven slow-fast host-parasite system of equations for a slow flukes population (host) and a fast Unikaryon hyperparasite population (parasite). The model exhibits two branches of the critical curve crossing in a transcritical bifurcation scenario. We discuss two thresholds due to immediate and delayed exchange of stability effects; and we derive algebraic relationships for parameters of the periodic solution in the limit of the infinite ratio of the time scales. Flukes, which are the host species in our model, parasitise cockles and in turn are hyperparasitised by the microsporidian Unikaryon legeri; the life cycle of flukes includes several life stages and a number of different hosts. That is, the flukes-hyperparasite system in a cockle is, naturally, part of a larger estuarine ecosystem of interacting species involving parasites, shellfish and birds which prey on shellfish. A population dynamics model which accounts for one system of such multi-species interactions and includes the fluke-hyperparasite model in a cockle as a subsystem is presented. We provide evidence that the threshold effect we observed in the flukes-hyperparasite subsystem remains apparent in the multi-species system. Assuming that flukes damage cockles, and taking into account that the hyperparasite is detrimental to flukes, it is natural to suggest that the hyperparasitism may support the abundance of cockles and, thereby, the persistence of the estuarine ecosystem, including shellfish and birds. We confirm the possibility of the existence of this scenario in our model, at least partially, by removing the hyperparasite and demonstrating that this may result in a substantial drop in cockle numbers. The result

  4. Dynamics and growth of the cockle, Cerastoderma edule, on an intertidal mud-flat in the Danish Wadden sea: Effects of submersion time and density

    NASA Astrophysics Data System (ADS)

    Thomas Jensen, K.

    A descriptive study was conducted on a dense intertidal population of the infaunal bivalve Cerastoderma edule in the Danish Wadden Sea to investigate effects of submersion time and intraspecific density on recruitment and shell growth. Following a severe winter (1981/1982), a successful settlement occurred in June-July 1982. Spat numbers varied along the tidal gradient. At the end of July they reached a maximum density of about 60 000 ind·m -2 in the lower intertidal zone. Their abundance declined rapidly during the following two months. After that the mortality rate was low and in the lower intertidal zone 2500 ind·m -2 survived to the age of 2. Recruitment was insignificant both in 1983 and 1984, probably due to the high standing stock of cockles born in 1982. The distribution pattern of cockles along the tidal transect established during settlement in July 1982 existed until the population vanished in the severe winter of 1984/85. The spat grew from settlement until mid-September and resumed growth during the following spring and early summer. The mean length attained by the cockles after 3 growing seasons at the station with the largest cockles was only 18.4 mm, which is far below lengths recorded elsewhere. Annual growth rates of individual cockles generally showed an increase with increasing submersion time, in particular during their second growing season. In their third year, however, growth rate was extremely low at the station with the highest density. Intraspecific competition among cockles is suspected to be a major cause of such growth rates exhibited by cockles at high densities (>2000·m -2) both during the present study and an earlier (1932-34) study in this area by Thamdrup. Cockles in nearby low-density populations showed higher growth rates, reaching mean lengths of more than 26 mm after 2 or 3 growing seasons.

  5. Altered membrane lipid composition and functional parameters of circulating cells in cockles (Cerastoderma edule) affected by disseminated neoplasia.

    PubMed

    Le Grand, Fabienne; Soudant, Philippe; Marty, Yanic; Le Goïc, Nelly; Kraffe, Edouard

    2013-01-01

    Membrane lipid composition and morpho-functional parameters were investigated in circulating cells of the edible cockle (Cerastoderma edule) affected by disseminated neoplasia (neoplastic cells) and compared to those from healthy cockles (hemocytes). Membrane sterol levels, phospholipid (PL) class and subclass proportions and their respective fatty acid (FA) compositions were determined. Morpho-functional parameters were evaluated through total hemocyte count (THC), mortality rate, phagocytosis ability and reactive oxygen species (ROS) production. Both morpho-functional parameters and lipid composition were profoundly affected in neoplastic cells. These dedifferentiated cells displayed higher THC (5×), mortality rate (3×) and ROS production with addition of carbonyl cyanide m-chloro phenylhydrazone (1.7×) but lower phagocytosis ability (½×), than unaffected hemocytes. Total PL amounts were higher in neoplastic cells than in hemocytes (12.3 and 5.1 nmol×10(-6) cells, respectively). However, sterols and a particular subclass of PL (plasmalogens; 1-alkenyl-2-acyl PL) were present in similar amounts in both cell type membranes. This led to a two times lower proportion of these membrane lipid constituents in neoplastic cells when compared to hemocytes (20.5% vs. 42.1% of sterols in total membrane lipids and 21.7% vs. 44.2% of plasmalogens among total PL, respectively). Proportions of non-methylene interrupted FA- and 20:1n-11-plasmalogen molecular species were the most impacted in neoplastic cells when compared to hemocytes (⅓× and ¼×, respectively). These changes in response to this leukemia-like disease in bivalves highlight the specific imbalance of plasmalogens and sterols in neoplastic cells, in comparison to the greater stability of other membrane lipid components. PMID:23333874

  6. Cockle Cerastoderma edule fishery collapse in the Ría de Arousa (Galicia, NW Spain) associated with the protistan parasite Marteilia cochillia.

    PubMed

    Villalba, Antonio; Iglesias, David; Ramilo, Andrea; Darriba, Susana; Parada, José M; No, Edgar; Abollo, Elvira; Molares, José; Carballal, María J

    2014-04-23

    The highest shellfishery catch in Galicia (NW Spain) has traditionally been cockle Cerastoderma edule. The shellfish bed located in Lombos do Ulla (Ría de Arousa) used to be among those with the highest cockle production; however, cockle mortality rate increased sharply in this bed in April 2012, reaching 100% in May 2012. Salinity and temperature were discounted as potential causes of the mortality. Marteiliosis, which was first detected in February 2012 and reached 100% prevalence in April 2012, was identified as the most probable cause. Marteiliosis had never been detected in Galician cockles, but extensive surveillance of the Galician coast in May to July 2012 detected marteiliosis in most cockle beds of the Ría de Arousa, whereas it was not found in other rías; 2 mo later, the cockle catch in the Ría de Arousa became negligible. Examination of the aetiological agent of marteiliosis with light and transmission electron microscopy supported its assignation to the genus Marteilia; morphological features showed similarity, but not complete identity, with the recently described species M. cochillia Carrasco et al., 2013. Regarding its molecular characterisation, a consensus sequence of 4433 bp containing a partial sequence of the intergenic spacer region, the complete 18S rRNA gene and a partial sequence of the first internal transcribed spacer region was obtained. The obtained sequences were compared with those available for Marteilia spp. and other Paramyxida. Molecular data support that this parasite corresponds to the species M. cochillia, and a PCR assay was designed for its specific diagnosis. The association of huge cockle mortality with M. cochillia infection urges extreme caution to avoid spreading this disease. PMID:24781796

  7. Population structure and growth rates at biogeographic extremes: a case study of the common cockle, Cerastoderma edule (L.) in the Barents Sea.

    PubMed

    Genelt-Yanovskiy, Evgeny; Poloskin, Alexey; Granovitch, Andrei; Nazarova, Sophia; Strelkov, Petr

    2010-01-01

    A descriptive study of population structure, growth rates and shell morphometry was conducted on nine intertidal populations of the infaunal bivalve Cerastoderma edule in the Murmansk coast of the Barents Sea. Year-to-year population dynamics was analyzed during 2002-2006 on a tidal flat Dalniy Plaj (eastern Murmansk coast). The region constitutes the northern extremes of C. edule range where populations occupied the middle to low intertidal zone and were characterized by low densities. The distribution of age groups and unstable age structure across years in the cockle populations suggest irregular recruitment. Growth rates and shell morphometry showed little variation across the populations studied, and there were no gradient changes from the west to the east parts of Murmansk coast. PMID:20347100

  8. Effect of some habitual cooking processes on the domoic acid concentration in the cockle (Cerastoderma edule) and Manila clam (Ruditapes philippinarum).

    PubMed

    Vidal, A; Correa, J; Blanco, J

    2009-07-01

    The effect of cooking on the concentration and burden of domoic acid in two bivalve molluscs was studied. The Manila clam (Ruditapes philippinarum) and cockle (Cerastoderma edule) were subjected to steaming and boiling, respectively. In both cases, factorial plans were used to evaluate the effects of common cooking methods and the variations likely to take place during the cooking procedure (cooking time and salt concentration in both species, in addition to ethanol percentage in Manila clam). The domoic acid concentration and toxin content were affected by cooking in very different ways in the two species studied. The cockle lost a significant part of its domoic acid content, while the clam did not. Since the weight of the soft tissues in cooked bivalves was lower than in the raw samples in both species, the toxin concentration decreased less than the toxin burden in the cockle, while it increased in the clam, where the toxin burden did not change significantly. Among the cooking variables tested, only cooking time had a noticeable effect on the domoic acid content in the clam and cockle, with the bivalves that were cooked for a longer time having smaller amounts of toxin. It is clear that cooking affects the toxin concentration in bivalves in a way that is species specific. This characteristic must be taken into account when evaluating epidemiological information, establishing allowable toxin levels and in cases where pre-processing treatments such as cooking or similar methods are used in monitoring systems. PMID:19680984

  9. Calcimass and carbonate production by molluscs on the tidal flats in the Dutch Wadden Sea: II the edible cockle, cerastoderma edule

    NASA Astrophysics Data System (ADS)

    Beukema, J. J.

    Production of shell lime by the edible cockle Cerastoderma (Cardium) edule living on the tidal flats of the Dutch Wadden Sea was assessed from estimates gathered twice-annually during the period 1968 to 1982 on abundance, age composition and growth rates at 15 sampling places on Balgzand, a 50 km 2 tidal flat area. Large-scale surveys showed Balgzand to be a representative for the 1300 km 2 tidal flats of the Dutch Wadden Sea. Calcimass of the shells of the standing stock of living cockles increased during the period of observation from about 50 to about 200 g · m -2. The long-term average amounted to 104 g · m -2. Mean annual values for production and elimination were estimated at 118 and 114 g · m -2 · a -1, respectively. Turn-over rates thus amounted to about 1.1 a -1. As a consequence of the high between-years variability of the rates of both recruitment and mortality, all population parameters varied strongly from year to year. Mean annual carbonate production by cockles on the tidal flats of the Wadden Sea is estimated at 234 thousand m 3 (156 million kg) but this estimate is far from precise (95% confidence limits being about 100 to 400 thousand m 3). About {3}/{4} of this quantity will become available for shell fishery. The present level of exploitation of the stock of cockle shells slightly exceeds the lower limit of the long-term production estimate.

  10. Ingestion, enzymatic digestion and absorption of particles derived from different vegetal sources by the cockle Cerastoderma edule

    NASA Astrophysics Data System (ADS)

    Arambalza, U.; Urrutia, M. B.; Navarro, E.; Ibarrola, I.

    2010-10-01

    Ingestion, enzymatic digestion and absorption of particulate detrital matter derived from six different vegetal sources by the common cockle Cerastoderma edule was analyzed in a series of seasonal experiments performed in March, May and October 2005. Two green macroalgae: Ulva lactuca and Enteromorpha sp; two vascular plants: Spartina maritima and Juncus maritimus, the red macroalgae Gracilaria gracilis; and the microalgae Isochrysis galbana were used in experiments. Detrital matter was elaborated by freeze-drying, grinding and sieving (< 63 μm) vegetal tissues. Mono-specific detrital diets of similar organic content (≈ 60-70%) were elaborated by mixing detritus with ashed silt. We measured i) the biochemical composition of different detritus, ii) physiological components of the absorptive balance (i.e. clearance, ingestion, rejection and absorption rate and absorption efficiency), iii) the capability of the digestive gland to hydrolyze carbohydrates from different detritus (digestibility), as well as iv) glandular cellulase and xylanase activities. Detritus type, season and the interaction detritus-season exerted significant effects upon all the physiological components of absorptive balance. Effects were light at the pre-absorptive level, however, huge variations associated to absorption efficiency promoted large significant differences in absorption rates (AR) of different kind of detritus: irrespective of season, highest values corresponded to cockles fed the green macroalgae ( Ulva and Enteromorpha) and lowest to those fed the vascular plant Juncus maritimus. Recorded significant differences in enzymatic digestibility among detritus were found to explain ≈ 40% of differences recorded in AR, and the following regression could be fitted: AR = 0.232 (± 0.032) * Digestibility + 0,072 (± 0.015); r 2 = 0.415; F = 51.036; p < 0.001. Digestibility of Ulva and Enteromorpha was found to be significantly correlated with cellulase activity in the digestive gland

  11. A growth model of the cockle ( Cerastoderma edule L.) tested in the Oosterschelde estuary (The Netherlands)

    NASA Astrophysics Data System (ADS)

    Rueda, Jose L.; Smaal, Aad C.; Scholten, Huub

    2005-11-01

    We present an ecophysiological model of the bivalve Cerastoderma edule that simulates individual growth and reproduction under ambient conditions in temperature and food availability in the Oosterschelde estuary, SW Netherlands. The model contains feedback loops in the uptake and metabolism of food and in the partitioning of carbon to the internal state variables: somatic tissue, storage, organic shell matrix and gametes. The model was calibrated for 24 parameters, based on random distributions of parameter values. This procedure includes an estimate of confidence intervals of the output variables. The simulated growth of shell length and animal wet and dry weight reflected the observed values of growth in the field for the period 1993 - 1997. The model is a tool for the integration of ecophysiological knowledge of this species and also for carrying-capacity studies of shellfish culture and for environmental management of populations in estuarine and coastal areas.

  12. Supernumerary chromosomes on Southern European populations of the cockle Cerastoderma edule: Consequence of environmental pollution?

    NASA Astrophysics Data System (ADS)

    Leitão, Alexandra; Chaves, Raquel; Joaquim, Sandra; Matias, Domitília; Ruano, Francisco; Guedes-Pinto, Henrique

    2008-08-01

    Cerastoderma edule (Cardiidae) has a diploid chromosome number of 2 n = 38, its karyotype consisting of 12 submetacentric, 4 subtelocentric and 3 telocentric chromosome pairs. Hyperdiploid cells had previously been observed in two populations of the Northern Galician coasts (northwest of Spain). The supernumerary chromosomes being easily distinguished by their reduced differentiated size and by their intra- and inter-individual variability. After the recent observation of 35% of cells with supernumerary chromosomes in a population of the Southern Galician coasts (Vigo) and 15% of cells with supernumerary chromosomes in a population of the south of Portugal (Ria Formosa, Algarve), we attempted, in this paper, an elucidation of the nature of these supernumerary chromosomes, by differential banding technique with restriction enzymes on these hyperdiploid cells. Analysis of the restriction enzyme banding of the 2 n > 38 karyotypes led us to propose the occurrence of a chromosomal fission event involving the largest submetacentric chromosome pair. This study represents the first description of the occurrence of a possible chromosomal fission in marine bivalves. Different levels of environmental pollution are suggested as possible explanation for the differences observed on the proportion of hyperdiploid cells between the Southern Portugal population and the three Galician ones.

  13. Limitations of metallothioneins in common cockles (Cerastoderma edule) and sponges (Haliclona oculata) as biomarkers of metal contamination in a semi-enclosed coastal area.

    PubMed

    Aly, W; Williams, I D; Hudson, M D

    2014-03-01

    Poole Harbour is typical of many heavily anthropologically impacted semi-enclosed estuarine coastal areas under pressure from metal pollution across the world. This study examined the physiological significance of metal burdens within that sensitive area, and assessed the potential use of metallothionein (MT) concentrations in two organisms: the common cockle (Cerastoderma edule) and the Mermaid's glove sponge (Haliclona oculata) for mapping the spatial extent of the biological response to metal contamination. A spectrophotometric method was applied for detection of MT in the bivalve, and for the first time to detect MT in sponges. The results show that while some metal concentrations in cockle and sponge tissues and in their surrounding environment (water and sediment) could be related to sources of metal contamination, MT values in the soft tissue of cockles and whole tissue of sponges are not. No relation could be found between MT in both cockles and sponges, and any of the tested metals (As, Cd, Cr, Cu, Pb, Hg, Ni, Ag, Sn, Zn). Furthermore, some of the lowest MT concentrations were detected in heavily polluted areas, indicating that MT concentrations in tested organisms are not exclusively associated with metal concentrations, as other environmental factors could affect induction of this protein. Organisms probably have a high tolerance to metal contamination and chronic exposure to a high level of contamination resulted in developing a variety of detoxification mechanisms. Results indicate that further study of metal stress in this type of ecosystem may need to examine other indicator species and/or apply a different biomonitoring technique. PMID:24378929

  14. Population dynamics and secondary production of the cockle Cerastoderma edule: A comparison between Merja Zerga (Moroccan Atlantic Coast) and Arcachon Bay (French Atlantic Coast)

    NASA Astrophysics Data System (ADS)

    Gam, Mériame; de Montaudouin, Xavier; Bazairi, Hocein

    2010-04-01

    Cockle ( Cerastoderma edule) population dynamics were studied at the southern limit of the distribution of this marine bivalve in Merja Zerga, Morocco. Parameters such as growth, mortality, and production were compared with those of a population at Arcachon Bay (France) a site in the center of the cockle's range. At each sampling period between two and three cohorts were simultaneously observed at each site and the average total abundance was usually higher at Merja Zerga. Recruitment occurred at both sites in spring when temperature rose above 19 °C, independently of the month. In Merja Zerga, winter recruitment was also observed at one occasion, following high sediment disturbance. The first year (2005-06) at Merja Zerga, the mortality rate was close to nil for juveniles and was Z = 1.5 yr - 1 for adults, providing a high production (64 g dry weight m - 2 yr - 1 ). At Arcachon during the same period, the juvenile mortality rate was Z = 10.9 yr - 1 , the adult mortality rate was 3.4 yr - 1 and production was 26 gDW m -2 yr - 1 . The second year (2006-07), mortality after recruitment was much higher ( Z = 8.6 yr - 1 , for juveniles) and similar to what was observed at Arcachon ( Z = 8.4 yr - 1 ). Mortality rate of adults was higher at Merja Zerga ( Z = 3.0 yr - 1 ) than at Arcachon ( Z = 1.5 yr - 1 ). Production was lower at Arcachon than at Merja Zerga although growth performances were higher at Arcachon. The higher growth performance at Arcachon ( Φ' = 3.3) was mainly due to high asymptotic length ( L∞ = 38 mm) and was related to low intraspecific competition compared to Merja Zerga where cockle abundance was higher ( Φ' = 3.1, L∞ = 31 mm). P/B was low in both sites and slightly higher at Arcachon (1.1-1.5 against 1.0-1.1 yr - 1 ). At Arcachon, recruitment was correlated with temperature, a peak occurring when temperature rose above 19 °C (June-July). At Merja Zerga, recruitment was already 2-3 months earlier but was not significantly correlated to

  15. Changes of paralytic shellfish toxins in gills and digestive glands of the cockle Cerastoderma edule under post-bloom natural conditions.

    PubMed

    Costa, Sara T; Vale, Carlos; Raimundo, Joana; Matias, Domitília; Botelho, Maria João

    2016-04-01

    Concentrations of the paralytic shellfish toxins C1+2, C3+4, GTX5, GTX6, dcGTX2+3, dcSTX, dcNEO, GTX2+3, GTX1+4, STX and NEO were determined by LC-FLD in composite samples of digestive glands and gills of Cerastoderma edule cockle. The specimens were sampled in Aveiro lagoon, Portugal, under natural depuration conditions (days 0, 8, 12, 14, 19, 21 and 25) after exposure to a bloom of Gymnodinium catenatum. Individual paralytic shellfish toxins indicated different pathways of elimination and biotransformation in digestive gland and gills. Toxin concentrations in gills were lower than in digestive gland. Most of the quantified toxins in digestive gland decreased during the 25 days of observation according to negative exponential curves, and only GTX5, GTX6 and NEO showed slight irregularities with time. Concentrations of C1+2, C3+4 and dcGTX2+3 in gills decreased progressively, however GTX5, GTX6 and dcSTX showed pronounced increases. Higher concentrations of those toxins in days 8 and 12 in comparison to the initial value (day 0) indicate conversion of other toxins into GTX5, GTX6 and dcSTX during those periods. It appears that inter-conversion of toxins occurs as G. catenatum cells are retained in gills before being transferred to other compartments. PMID:26874623

  16. Partitioning of paralytic shellfish toxins in sub-cellular fractions of the digestive gland of the cockle Cerastoderma edule: Changes under post-bloom natural conditions.

    PubMed

    Botelho, Maria João; Raimundo, Joana; Vale, Carlos; Ferreira, João Gomes

    2014-06-01

    Concentrations of paralytic shellfish toxins (C1+2, B1, dcGTX2+3, dcSTX, GTX2+3 and STX) were determined by LC-FLD in composite samples of digestive glands of the cockle Cerastoderma edule and in each sub-cellular particulate fractions obtained after differential centrifugation (nuclei+debris, mitochondria, lysosomes and microsomes). The specimens were sampled during the exposure to a bloom of Gymnodinium catenatum (day 0) and in the subsequent 8, 12, 14, 19, 21 and 25 days under natural depuration conditions. Toxin profiles of digestive glands were dominated by C1+2 followed by B1 and dcGTX2+3, although the proportion between C1+2 and B1 contents decreased with the time, indicating a slower elimination of B1. All toxins, except GTX2+3 and STX, were quantified in the four sub-cellular fractions. The content of the quantified toxins decreased most markedly in nuclei+debris and microsomal fractions, during the first eight and 12 days, respectively. Conversely, different patterns were observed among toxins in mitochondrial and lysosomal fractions. The less accentuated decreases of dcGTX2+3 and dcSTX contents in the mitochondrial fraction may have resulted from the conversion of other toxins, like C1+2 and B1, associated with enzymatic activities in that fraction. The largest discrepancy was registered in lysosomal fraction for B1, since its content increased after eight days of post-bloom conditions. Input of B1 may come from the conversion of other toxins, like the abundant B2 and C1+2. These transformations are associated to the major role of lysosomes in the intra-cellular digestive process of materials acquired through vesicular transport. PMID:24736027

  17. Genetic variability and relationships for populations of Cerastoderma edule and of the C. Glaucum complex

    NASA Astrophysics Data System (ADS)

    Hummel, H.; Wolowicz, M.; Bogaards, R. H.

    Genetic variability and relationships of populations of the cockles Cerastoderma edule and of the C. glaucum complex in Europe were determined by means of isoenzyme electrophoresis. Distinct isoenzyme markers allowed a clear distinction between these two taxa. C edule showed a higher genetic intra-population variability than the other cockle species. The imbalance of the genotypes within popuulation and the inter-population differentiation of the C. glaucum complex are stronger than in C. edule. The genetic variability is related to the different habitats of the species, the members of the C. glaucum complex living in more isolated areas and having more limited gene flow.

  18. The effect of macrofaunal disturbance on Cerastoderma edule post-larvae

    NASA Astrophysics Data System (ADS)

    Whitton, Timothy Andrew; Jenkins, Stuart Rees; Richardson, Christopher Allan; Hiddink, Jan Geert

    2016-06-01

    Populations of the Common European cockle (Cerastoderma edule) often have highly patchy distributions and variable recruitment success. One of the proposed reasons is that high densities of filter feeders and/or bioturbators are thought to reduce the success of larval settlement and post-settlement survival, but the direct causal processes driving these observations are not clearly identified and validated. Through combined field and laboratory experiments, we test the hypothesis that macrofauna cause decreases in post-larval density through feeding and movement activities. The effect of excluding the bioturbating lugworm Arenicola marina and filter-feeding adult cockles on post-larval cockle densities was estimated in separate field experiments at two locations from the time of initial larval settlement in May 2012 to late summer August 2012. Lugworm exclusion led to a significant increase in cockle post-larval densities whereas the opposite was true for adult cockles, where exclusion led to a reduction in C. edule post-larval density. Although clear effects were observed in the field, experiments conducted in the laboratory failed to detect changes in mortality or byssus drifting of post-larvae as a consequence of macrofaunal activity. This study demonstrates that the presence of macrofauna can have both positive and negative effects on post-settlement density of C. edule post-larvae. Thus the density, distribution and identity of macrofauna have significant effects on the density and spatial distribution of C. edule post-larvae during the post-settlement period. These observations have implications for conservation and fishery management of this species.

  19. Clearance rates of Cerastoderma edule under increasing current velocity

    NASA Astrophysics Data System (ADS)

    Fernandes, S.; Sobral, P.; van Duren, L.

    2007-05-01

    Estimates of clearance rates (CR) of Cerastoderma edule (300 ind. m -2) as a function of free-stream current velocity ( U) (from 5 to 40 cm s -1) were compared between a small annular (60 l) and a large racetrack (8850 l) flume with different hydrodynamic conditions. Results showed that the flumes differ considerably in their hydrodynamic characteristics. The relationship between CR and U is different in the two flume tanks, however there appears to be a straightforward unimodal trend between CR and shear velocity ( U*). It was found that the cockles themselves influence the benthic boundary layer (BBL) characteristics, by causing steeper velocity gradients and increasing the mixing over the cockle bed compared to bare sediment. This provides new evidence on how endobenthic organisms can affect the BBL. However, the influence of CR on U* could not be quantified because these parameters have interactive effects that cannot be dissociated.

  20. Long-term epidemiological study of disseminated neoplasia of cockles in Galicia (NW Spain): temporal patterns at individual and population levels, influence of environmental and cockle-based factors and lethality.

    PubMed

    Díaz, S; Iglesias, D; Villalba, A; Carballal, M J

    2016-09-01

    The dynamics of disseminated neoplasia (DN) affecting cockles Cerastoderma edule (L.) in Galicia was addressed at individual and population levels. Early stage of DN was characterized by isolated neoplastic cells occurring in branchial vessels or in the connective tissue of gills, mantle, gonad or digestive gland. As disease progressed, the neoplastic cells appeared loose in foci and became widely distributed throughout the organs. In advanced stages, the connective tissue of most organs was infiltrated by neoplastic cells, which displaced normal cells, leading to the loss of the normal tissue/organ architecture. Host defence reaction was occasionally observed. A field survey performed for 7 years, in two cockle beds located in different Galician Rías, showed that DN is a hyperendemic disease usually present all year-round at high prevalence in adult cockles but with annual prevalence minima in spring likely due to the death of heavily affected cockles, concurrently with gonad ripeness-spawning. DN was detected in the cockles ranging from 10 to 39 mm in size; the highest DN prevalence and severity corresponded to the cockles of intermediate size/age (22-29 mm/0.7-1 year old). Sex did not appear to influence DN occurrence. An inhibitory effect of DN on cockle gametogenesis was detected. PMID:26813312

  1. Disturbance of intertidal soft-sediment benthic communities by cockle hand raking

    NASA Astrophysics Data System (ADS)

    Kaiser, M. J.; Broad, G.; Hall, S. J.

    2001-05-01

    Recent awareness of the ecosystem effects of fishing activities on the marine environment means that there is a pressing need to evaluate the direct and indirect effects of those activities that may have negative effects on non-target species and habitats. The cockle, Cerastoderma edule (L.) is the target of a commercial and artisanal fishery that occurs in intertidal and estuarine habitats across Northern Europe. Cockles are harvested either mechanically using tractor dredges or suction dredges or by large numbers of individual fishers using hand rakes. This study examined the effects of hand raking on the non-target species and under-sized cockles associated with intertidal cockle beds and the effects of size of the patch of sediment disturbed on subsequent recolonisation. Hand raking led to an initial three-fold increase in the damage rate of under-sized cockles compared with control plots. The communities in both small and large raked plots showed community changes relative to control plots 14 days after the initial disturbance. The small raked plots had recovered 56 days after the initial disturbance whereas the large raked plots remained in an altered state. Samples collected over a year later indicated that small-scale variations in habitat heterogeneity had been altered and suggest that while effects of hand raking may be significant within a year, they are unlikely to persist beyond this time-scale unless there are larger long-lived species present within the community.

  2. Review: Bucephalus minimus, a deleterious trematode parasite of cockles Cerastoderma spp.

    PubMed

    Magalhães, L; Freitas, R; de Montaudouin, X

    2015-04-01

    Trematodes are the most prevalent and abundant macroparasites in coastal waters. They display a complex life cycle with alternation of free-living and parasitic stages generally involving three host species. The most deleterious stage is in the first intermediate host (a mollusc) where the parasite penetrates as miracidium larvae and asexually multiplicates in sporocysts/rediae to provide cercariae larvae. However, due to basic low prevalence in ecosystems, this system remains difficult to study. Taking the example of the cockle (Cerastoderma edule), an exploited bivalve along North-Eastern Atlantic coasts, and Bucephalus minimus, its most prevalent parasite as first intermediate host, we summarised the 51 most relevant papers (1887-2015). Besides, a 16-year monthly monitoring was performed at Banc d'Arguin (Atlantic coast of France), and allowed to obtain a sufficient number of infected cockles (276 out of 5,420 individuals) in order to provide new information concerning this parasite/host system. Sporocysts (diameter 80-500 μm) and developing cercariae (length 300-500 μm) are not visible before cockle reaches 16-mm shell length and then prevalence increases with host size. Seasonality of infection was not observed but variation of prevalence was significant among years and negatively correlated to the temperature of the former year, which could correspond to the period of infection by miracidium. Seven other species of trematode were identified in cockles as second intermediate host. For six of them, metacercariae abundance per individual was 2 to 12 folds higher in B. minimus-infected cockles, exacerbating the potential negative impact on host. From the parasite point of view, metacercariae can be considered as hitchhikers, taking advantage of the abnormal migration of B. minimus-infected cockles to the sediment surface where they become more vulnerable to predators that are also the final hosts of many of these parasites. PMID:25681142

  3. Erodibility of a mixed mudflat dominated by microphytobenthos and Cerastoderma edule, East Frisian Wadden Sea, Germany

    NASA Astrophysics Data System (ADS)

    Andersen, T. J.; Lanuru, M.; van Bernem, C.; Pejrup, M.; Riethmueller, R.

    2010-04-01

    Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment erodibility and the temporal variation. The study site was a mixed mudflat situated in the mesotidal Baltrum-Langeoog tidal basin at the East Frisian barrier coast. The mud content at the site was about 35% and the filter-feeding cockle Cerastoderma edule was the dominating macrozoobenthic species (by biomass). The erodibility of the sediment showed strong temporal variation with high erosion thresholds in spring and late summer and significantly lower thresholds during the rest of the study period. The erosion thresholds were strongly dependent on the contents of chlorophyll a (chl a) and colloidal carbohydrates, both indicators of the content of microphytobenthos, in this environment primarily benthic diatoms. The content of microphytobenthos was high in September 2002 and April 2003, and regression analysis indicated that this was the only likely reason for the low erodibility found at these times. A biostabilisation index of about 4.5 was found for a situation with both abundant biofilms and cockles. A direct influence of Cerastoderma edule on erodibility was not observed, in contrast to other recent studies. The presence of C. edule at the site results in biodeposition of fine-grained material and the presence of C. edule will therefore probably increase the content of fine-grained sediments at the surface compared to an abiotic situation. Increasing the amount of fine-grained material in mixed sediments has previously been shown to reduce the erodibility of the sediments and C. edule will therefore in this way indirectly stabilize the bed. However, although C. edule may constitute the main part of the biomass at some intertidal sites, other and more vigorous bioturbators and

  4. Effects of suction-dredging for cockles on non-target fauna in the Wadden Sea [rapid communication

    NASA Astrophysics Data System (ADS)

    Hiddink, J. G.

    2003-12-01

    Suction dredging for cockles removes large cockles from tidal flats and may also cause mortality of non-target fauna and make the habitat less suitable for some species. This study examines whether suction dredging for cockles on tidal flats of the Dutch Wadden Sea had affected densities of non-target fauna, directly after fishing and one year later. Densities of non-target fauna in two randomly chosen undredged locations were compared to densities at the surrounding heavily commercially dredged area. A significant negative effect of cockle dredging on densities of 0-group Macoma balthica was observed and this effect persisted one year after dredging. The dredged area appeared to be less suitable for settlement of mussels Mytilus edulis. No significant effects of dredging on the mudsnail Hydrobia ulvae and on 0 and 1-group C. edule were found. For the mobile young Macoma balthica it seems unlikely that the effect found after one year was still due to the mortality caused by dredging and this suggests that the habitat was less suitable as a consequence of dredging. Thus, even in the highly dynamic ecosystem of the Wadden Sea, effects of bottom disturbance by cockle dredging may persist after one year.

  5. Cytomorphology and PCNA expression pattern in bivalves Mytilus galloprovincialis and Cerastoderma edule with haemic neoplasia.

    PubMed

    Carella, Francesca; Figueras, Antonio; Novoa, Beatriz; De Vico, Gionata

    2013-07-01

    Haemic neoplasia (HN) is a pathologic condition reported in several bivalve species in different geographic areas. In this study we describe the cytomorphological features and the proliferative behaviour, assessed by the proliferating cell nuclear antigen (PCNA), of HN in common cockle Cerastoderma edule and Mediterranean mussel Mytilus galloprovicialis. In mussels the presence of at least 5 types of atypical haemocytes was detected, including A- and B-type cells, previously described in M. edulis and Mytilus sp., with predominance of A-type cells in early phases of the disease and B-type cells in more advanced stages. PCNA immunostaining was positive for 97 to 100% of the neoplastic cells, with both cytoplasmic (A cells) and nuclear patterns (B cells). Conversely, in C. edule there was no distinctive morphological cell sub-population, and staining atypical haemocytes with PCNA (range 93 to 100%) showed nuclear expression in early phases of disease and cytoplasmic expression in more advanced stages. The above findings suggest distinct histo-pathogenetic pathways for HN in mussels and common cockles. PMID:23836773

  6. Cockle infection by Himasthla quissetensis - I. From cercariae emergence to metacercariae infection

    NASA Astrophysics Data System (ADS)

    de Montaudouin, Xavier; Blanchet, Hugues; Desclaux-Marchand, Céline; Lavesque, Nicolas; Bachelet, Guy

    2016-07-01

    The European cockle (Cerastoderma edule) is an exploited bivalve along the North-Eastern Atlantic semi-sheltered ecosystems. Its population dynamics are driven by numerous environmental factors, including parasitism, particularly by trematodes. The complex life cycle of trematodes includes a free living stage (cercaria) between the first (a mollusk) and the second (an invertebrate or a vertebrate) intermediate hosts. Taking the example of Himasthla quissetensis, a dominant trematode in Arcachon Bay (France) utilizing Nassarius reticulatus as first intermediate host and the cockle as second intermediate host, we investigated the correlation between cockle infection and cercariae emergence by N. reticulatus, including the role of water temperature and light. Experimental and field data provided evidence that cercariae emergence from N. reticulatus took place during the night and for water temperature comprised between 15 °C and 22 °C (optimum at 20 °C). The lifespan of cercariae did not exceed 48 h and 50% of them were no more infectious after 7 h. A model was designed (emergence = f(water temperature)) in order to calculate an average monthly cercarial emergence rate according to water temperature that was daily recorded for 5 years (1998-2002). Concomitantly, non-infected cockles were transplanted each of these years in order to assess the infection rate by H. quissetensis. Infection occurred strictly for the same water temperatures (and dates) as those expected for cercariae emergence. Within each year, there was often (but not always) a good correlation between the predicted number of emerging cercariae and the observed number of cercariae transformed into metacercariae in cockles. However, the among-years variability of cockle infection (× 4.4 range) was not explained by the predicted annual number of emerging cercariae. This study highlights the importance of water temperature and light in stimulating cercariae emergence which is closely related to the

  7. Environmental effects on shell microstructures of Cerastoderma edule

    NASA Astrophysics Data System (ADS)

    Milano, Stefania; Schöne, Bernd R.; Witbaard, Rob

    2015-04-01

    Bivalve shells serve as sensitive recorders of environmental conditions. However, reconstruction of a specific environmental parameter is still challenging. For example, variable shell growth rates simultaneously provide information on water temperature, food availability and food quality. Likewise, shell oxygen isotope values function as a dual proxy of water temperature and salinity (=oxygen isotope signature of the ambient water). Reconstruction of water temperature from δ18Oshell requires knowledge of δ18Oshell and vice versa. Unfortunately, the incorporation of trace elements in the shell is strongly controlled by biological effects and, hence, the element-to-calcium ratios of the shell are difficult to interpret in terms of environmental variables. Here, we studied if the structural properties (shell architecture, shell microstructures, fabrics) of the shell of the common cockle can function as an alternative proxy of environmental variables. Specimens of C. edule were collected alive from the intertidal zone of the North Sea. Temperature and salinity were monitored at the site where the shells lived on hourly basis for almost one year. Each portion of the shell was temporally contextualized with the tidally-deposited growth increments. Shell microstructures (composite prismatic structures) were analyzed under with a scanning electron microscope (SEM). The change of the size and shape of the mesocrystals was strongly correlated to water temperature during the growing season (May - Sep.). With rising temperatures, the size of mesocrystals increased and their morphology changed from rounded to elongated shape. Our findings suggest that shell microstructures of C. edule may serve a new, independent proxy for water temperature.

  8. Cockle infection by Himasthla quissetensis - II. The theoretical effects of climate change

    NASA Astrophysics Data System (ADS)

    de Montaudouin, Xavier; Blanchet, Hugues; Desclaux-Marchand, Céline; Bazairi, Hocein; Alfeddy, Nazik; Bachelet, Guy

    2016-07-01

    Numerous marine populations experience parasite pressure. This is the case of the cockles Cerastoderma edule which are often highly infected by trematode macroparasites. These parasites display a complex life cycle, with a succession of free-living and parasitic stages. Climate, and in particular temperature, is an important modulator of the transmission dynamics of parasites. Consequently, global change is thought to have implications for the epidemiology of infectious diseases. Using Himasthla quissetensis, a dominant parasite of cockles as 2nd intermediate host in Arcachon Bay (France), we used mathematical models of parasite emergence (cercariae) and parasite infection (metacercariae) in cockles as a function of water temperature, in order to study different scenarios of temperature increases. Globally, with a + 0.5 °C to + 6.0 °C simulation, cumulated emergence of cercariae and accumulation of metacercariae tended to decrease or stagnate, respectively. This is the consequence of a trade-off between sooner (spring) and later (autumn) cercariae emergence/infestation on one hand, and a longer inhibition period of cercariae emergence/infestation during the hottest days in summer. Using sea water temperature in Oualidia (Morocco) where mean annual sea temperature is 3 °C higher than in Arcachon Bay, our model predicted infestation all year long (no seasonality). The model gave a correct estimation of the total number of parasites that was expected in cockles. Conversely, observed infestation in Oualidia followed a seasonal pattern like in Arcachon Bay. These results suggest that, if temperature is a strong driver of parasite transmission, extrapolation in the framework of climate change should be performed with caution.

  9. Metapopulation structure in the lagoon cockle Cerastoderma lamarcki in the northern Wadden Sea

    NASA Astrophysics Data System (ADS)

    Reise, Karsten

    2002-11-01

    Benthic invertebrates in discontinuous inshore habitats and with short or no pelagic larval dispersal are likely to exhibit regional metapopulation dynamics with partially isolated local populations. Near the island of Sylt, the bivalve Cerastoderma (Cardium) lamarcki (Reeve, 1844, syn. in part with C. glaucum Bruguiére, 1789) was widespread in intertidal seagrass beds, coexisting with the sibling species C. edule (Linné, 1758). However, the last C. lamarcki in this habitat was found in 1980. At present the lagoon cockle is restricted to disjunct ditches, creeks and ponds within island salt marshes. There it differs in year-class structure between localities. Successful recruitment events did not coincide. At one locality, a period with regular recruitment was followed by 5 years of recruitment failure, resulting in an overaged population probably at the rim of extinction. In a nearby brackish pond, extinction was followed by recolonization 3 years later. Other lagoonal habitats which seem to be suitable are without cockles. It is speculated that small and isolated habitats occasionally receive colonizers by eggs and juveniles adhering to avian vectors.

  10. Effects of CO2 enrichment on cockle shell growth interpreted with a Dynamic Energy Budget model

    NASA Astrophysics Data System (ADS)

    Klok, Chris; Wijsman, Jeroen W. M.; Kaag, Klaas; Foekema, Edwin

    2014-11-01

    The increase in human induced atmospheric CO2 level leads to an increase in ocean acidification (OA). Mitigation of this increase by storage of CO2 in abandoned marine oil and gas reservoirs is seen as an interesting cost effective solution. However, this involves a risk of CO2 loss causing localised reductions in seawater pH. In this paper we report on the effects of CO2 enhancement on the growth of the bivalve Cerastoderma edule in mesocosms. The experiments show significant reductions in shell length, shell weight and cockle flesh dry weight at increased CO2 level suggesting both direct (shell erosion) and indirect (metabolic) effects. Indirect effects were analysed and interpreted using a Dynamic Energy Budget model by describing changes in 3 metabolic processes: assimilation, maintenance, and growth. Based on cockle size data only we could not differentiate between these processes, however, by using variability of DEB parameter values in 11 bivalve species, we showed growth to be the least relevant process.

  11. Metapopulation structure in the lagoon cockle Cerastoderma lamarcki in the northern Wadden Sea

    NASA Astrophysics Data System (ADS)

    Reise, Karsten

    2003-01-01

    Benthic invertebrates in discontinuous inshore habitats and with short or no pelagic larval dispersal are likely to exhibit regional metapopulation dynamics with partially isolated local populations. Near the island of Sylt, the bivalve Cerastoderma (Cardium) lamarcki (Reeve, 1844, syn. in part with C. glaucum Bruguiére, 1789) was widespread in intertidal seagrass beds, coexisting with the sibling species C. edule (Linné, 1758). However, the last C. lamarcki in this habitat was found in 1980. At present the lagoon cockle is restricted to disjunct ditches, creeks and ponds within island salt marshes. There it differs in year-class structure between localities. Successful recruitment events did not coincide. At one locality, a period with regular recruitment was followed by 5 years of recruitment failure, resulting in an overaged population probably at the rim of extinction. In a nearby brackish pond, extinction was followed by recolonization 3 years later. Other lagoonal habitats which seem to be suitable are without cockles. It is speculated that small and isolated habitats occasionally receive colonizers by eggs and juveniles adhering to avian vectors.

  12. Modelling shellfish growth with dynamic energy budget models: an application for cockles and mussels in the Oosterschelde (southwest Netherlands).

    PubMed

    Troost, T A; Wijsman, J W M; Saraiva, S; Freitas, V

    2010-11-12

    Dynamic energy budget models for growth of individual cockles (Cerastoderma edule) and mussels (Mytilus edulis) are adjusted and calibrated to the Oosterschelde by formulating and parametrizing their functional responses using an extensive set of field observations. The resulting model predictions fit the observations satisfactorily. Results indicate that food quality and the importance of detritus as a food source are site-specific as well as species-specific. Despite these differences in their calibrated parameter values, both species show a very similar functional response. Compared with other systems, however, the functional responses of mussels in the present study are clearly higher than those of mussels in other systems. This may be explained by the absence of intra-specific competition in the measurement set-up that was used, and therefore supports the idea that the generally small functional response of M. edulis is caused by intra-specific competition. PMID:20921054

  13. Modelling shellfish growth with dynamic energy budget models: an application for cockles and mussels in the Oosterschelde (southwest Netherlands)

    PubMed Central

    Troost, T. A.; Wijsman, J. W. M.; Saraiva, S.; Freitas, V.

    2010-01-01

    Dynamic energy budget models for growth of individual cockles (Cerastoderma edule) and mussels (Mytilus edulis) are adjusted and calibrated to the Oosterschelde by formulating and parametrizing their functional responses using an extensive set of field observations. The resulting model predictions fit the observations satisfactorily. Results indicate that food quality and the importance of detritus as a food source are site-specific as well as species-specific. Despite these differences in their calibrated parameter values, both species show a very similar functional response. Compared with other systems, however, the functional responses of mussels in the present study are clearly higher than those of mussels in other systems. This may be explained by the absence of intra-specific competition in the measurement set-up that was used, and therefore supports the idea that the generally small functional response of M. edulis is caused by intra-specific competition. PMID:20921054

  14. An epidemic of cockles-associated hepatitis A in Singapore

    PubMed Central

    Goh, K. T.; Chan, L.; Ding, J. L.; Oon, C. J.

    1984-01-01

    An epidemic of serologically confirmed hepatitis A occurred between May and September 1983 in Singapore. The vehicle of transmission was traced to raw and partially cooked cockles, Anadara granosa, which had been imported from places with no sanitary control on the production. Strict controls on imported cockles are warranted. PMID:6335847

  15. Role of two contrasting ecosystem engineers ( Zostera noltii and Cymodocea nodosa) on the food intake rate of Cerastoderma edule

    NASA Astrophysics Data System (ADS)

    Brun, Fernando G.; van Zetten, Elleke; Cacabelos, Eva; Bouma, Tjeerd J.

    2009-03-01

    Seagrasses are well known ecosystem engineers that can significantly influence local hydrodynamics and the abundance and biodiversity of macrobenthic organisms. This study focuses on the potential role of the seagrass canopy structure in altering the abundance of filter-feeding organisms by modifying the hydrodynamic driven food supply. We quantified the effect of two ecosystem engineers with contrasting canopy properties (i.e. Zostera noltii and Cymodocea nodosa) on the food intake rate of a suspension-feeding bivalve Cerastoderma edule living in these seagrass meadows. Field experiments were carried out in two seagrass beds ( Z. noltii and C. nodosa) and bare sediment, located on sandflat characterised by a relatively high hydrodynamic energy from waves and currents. Results demonstrated that the filter-feeding rate was almost twofold increased when C. edule was inhabiting Z. noltii meadows (1.10 ± 0.24 μg Chl g Fresh Weight-1) when compared to cockles living on the bare sediment (0.65 ± 0.14 μg Chl g FW-1). Intermediate values were found within C. nodosa canopy (0.97 ± 0.24 μg Chl g FW-1), but filter feeding rate showed no significant differences with values for Z. noltii meadows. There were no apparent correlations between canopy properties and filter-feeding rates. Our results imply that food refreshment within the seagrass canopies was enough to avoid food depletion. We therefore expect that the ameliorated environmental conditions within vegetated areas (i.e. lower hydrodynamic conditions, higher sediment stability, lower predation pressure…) in combination with sufficient food supply to prevent depletion within both canopies are the main factors underlying our observations.

  16. The distribution of the amphipod Corophium arenarium in the Dutch Wadden Sea: relationships with sediment composition and the presence of cockles and lugworms

    NASA Astrophysics Data System (ADS)

    Flach, E. C.

    On the tidal flats in the Dutch Wadden Sea Corophium volutator is a dominant species of the upper intertidal zone; the closely related Corophium arenarium is usually found in the lower zone, but only in low densities (a few hundreds per m 2). A survey in the Dutch Wadden Sea showed that this zonation pattern was only present when a muddy sediment was found in the upper zone and a sandy in the lower zone. C. arenarium was restricted to sandy sediments, C. volutator to muddy sediments. Where a sandy sediment was found in the upper intertidal zone, C. arenarium locally occurred in relatively high densities (a few thousands per m 2). An aquarium experiment showed that C. arenarium actively avoided muddy sediments. Field experiments were carried out to study the influence of other macrozoobenthic species (known to affect the related C. volutator) on the abundance of C. arenarium. Within large defaunated areas small plots were stocked with different densities of the lugworm Arenicola marina and the cockle Cerastoderma edule. In small plots within a natural benthic community densities of these species were also augmented or (in A. marina) reduced. Strongly negative density-dependent effects of both A. marina and C. edule were found on the abundance of C. arenarium. In the natural situation, its densities showed A. marina to be the most important factor in determining the abundance of C. arenarium. In particular the removal of lugworms caused a strong increase in C. arenarium densities. These results agreed with the distribution of these species along a transect perpendicular to the shore of Schiermonnikoog, where a significant negative correlation was found between the densities of A. marina and C. arenarium. Aquarium experiments showed that the negative effect of cockles and lugworms must be due to migration rather than mortality in C. arenarium.

  17. Cadmium contamination of three bivalve species (oysters, cockles and clams) in Nord Médoc salt marshes (Gironde estuary, France): Geochemical survey and metal bioaccumulation kinetics

    NASA Astrophysics Data System (ADS)

    Baudrimont, M.; Schäfer, J.; Marie, V.; Maury-Brachet, R.; Bossy, C.; Durrieu, G.; Palvadeau, A.; Maneux, E.; Boudou, A.; Blanc, G.

    2003-05-01

    A historical Cd pollution of the Lot-Garonne River system (France) bas led to the contamination of sediment and water of the Gironde Estuary. In spite of the decrease of fluvial Cd inputs since the early 90ies, Cd concentrations in the Gironde oysters remain higher than European norms (5 μg.g^{-1} dry mass) and the “zone D” classification of the estuary prohibits bivalve production and harvesting for human consumption. A geochemical survey in salt marshes used for aquaculture (crustaceans) has been conducted in order to assess the heavy métal contamination level in these systems periodically alimented by the Gironde water, accompanied by caging experiments on three bivalve species of economical interest: oysters (Crassostrea gigas), cockles (Cerastoderma edule) and clams (Ruditapes philippinarum) to study heavy metal accumulation in these organisms. Distribution of heavy metals in this system is controlled by biogeochemical processes and is independent of routine water management. Contamination levels in the studied species indicate the high accumulation of Cd by oysters. On the other hand, Cd concentrations in benthic species, such as cockles and clams, are clearly lower than European safety limits for human consumption.

  18. Fine-scale spatial structure of the exploited infaunal bivalve Cerastoderma edule on the French Atlantic coast

    NASA Astrophysics Data System (ADS)

    Boldina, Inna; Beninger, Peter G.

    2013-02-01

    Investigations of biomass, production, and anthropogenic impact require knowledge of the spatial distribution of the species concerned. Studies of the spatial distribution of soft-sediment infauna are inherently difficult, because the organisms are generally not readily visible, necessitating painstaking excavation. Although the large-scale (tens of km) distribution patterns of infaunal bivalves have been studied previously, the fine-scale (1 to tens of meters) has received much less attention. We investigated the fine-scale spatial distribution of the edible cockle Cerastoderma edule at a fishing-impacted site and a non-impacted site on an intertidal mudflat in Bourgneuf Bay, France, in 2009-2010. A preliminary study using a 1 m spatial lag was performed to determine the optimum lags for a nested sampling design. Cohorts were identified using Bhattacharya-resolved size-frequency distributions and verification of isotropy, and the spatial characteristics of each cohort were determined using Moran's I auto-correlation coefficient. The non-impacted site presented one strongly-aggregated main cohort, C3, (Moran's I = 0.67 to - 0.34, spatial range 16 to 20 m, inter-patch distance 41 to 51 m). The impacted site presented two main cohorts, C2 (1.31 cm mean shell length, SL) and C3 (2.11 cm SL) both of which also showed a patchy spatial distribution (C2: Moran's I = 0.7 to - 0.72, spatial range 22 to 35 m; inter-patch distance 63 to 90 m; C3: Moran's I = 0.41 to - 0.63, spatial range 36 to 58 m, inter-patch distance not defined). The C3 cohort was less aggregated than the C2; possibly due to the homogenizing effect of fishing, which typically proceeds via a Lévy walk foraging model. Our results show that the spatial distributions of C. edule retained a strongly aggregated character over the 8 months of the study, suggesting that these characteristics are powerfully maintained by recruitment/post-recruitment processes, despite intense fishing pressure throughout the

  19. Utilization of Rice Husk as Pb Adsorbent in Blood Cockles

    NASA Astrophysics Data System (ADS)

    Rohaeti, Eti; Permata Sari, Wenny; Batubara, Irmanida

    2016-01-01

    Water pollution by lead affects blood cockles, a potential source of food. The aim of this research is to compare rice husk (RH) and rice husk carbon (RHC) in reducing the concentration of lead in blood cockles. RH and RHC were activated with NaOH 1 M, and then the optimal conditions and maximum capacity were determined. This research showed that RH and RHC had maximum adsorbancy capacities of 28.7326 mg/g and 51.5464 mg/g at optimal condition. The optimal adsorption condition for RH in 100 ml Pb solution is 0.32 gram, pH 5, for 4 hours. The optimal adsorption condition for RHC in 100 ml Pb solution is 0.20 gram, pH 5, for 2 hours. Lead content in blood cockles from the north waters of Jakarta (1.9658 mg/kg) is beyond the threshold limit. Lead adsorption by RH and RHC could reduce lead content in blood cockles by about 40% and 31%, respectively.

  20. Geochemical survey and metal bioaccumulation of three bivalve species (Crassostrea gigas, Cerastoderma edule and Ruditapes philippinarum) in the Nord Medoc salt marshes (Gironde estuary, France).

    PubMed

    Baudrimont, M; Schäfer, J; Marie, V; Maury-Brachet, R; Bossy, C; Boudou, A; Blanc, G

    2005-01-20

    A 15-month experiment combining a geochemical survey of Cd, Cu, Zn and Hg with a bioaccumulation study for three filter-feeding bivalve species (oysters, Crassostrea gigas; cockles, Cerastoderma edule; and clams, Ruditapes philippinarum) was conducted in a breeding basin of the Nord Medoc salt marshes connected to the Gironde estuary, which is affected by historic polymetallic pollution. Regular manual surface measurements of temperature, salinity, pH and dissolved O(2) concentration and hourly multiprobe in situ measurements throughout several periods for 6-8 weeks were performed. The geochemical behavior of metals in water, suspended particulate matter and sediment and their ecotoxicological impact on the three bivalve species were evaluated by in situ exposure of juvenile oysters (water column) and adult cockles and clams (sediment surface). The physico-chemical parameters reflected seasonal variations and basin management. A distinct daily periodicity (except salinity) indicated intense photosynthesis and respiration. In summer, low dissolved O(2) saturations ( approximately 40-50%) occurred in the early morning at 30 cm above the sediment, whereas in depressions, the water column near the sediment surface was suboxic. Cadmium, Zn and Cu concentrations in suspended particulate matter exceeded typical estuarine values and were much higher than the homogeneously distributed concentrations in different depth ranges of the basin sediment. Particles collected in sediment traps showed intermediate metal concentrations close to sediment values. These results suggest trace metal recycling due to reductive dissolution under suboxic conditions at the sediment surface resulting in trace metal release to the water column and adsorption onto suspended particles. Dissolved Cd, Zn and Hg concentrations (e.g. 13-136 ng l(-1); 0.3-25.1 microg l(-1) and 0.5-2.0 ng l(-1), respectively) in the basin corresponded to the concentration range typically observed in the Gironde estuary

  1. Isolation and identification among cockle isolates of Vibrio vulnificus isolated from Selangor, Malaysia

    NASA Astrophysics Data System (ADS)

    Kurdi Al-Dulaimi, Mohammed M.; Mutalib, Sahilah Abd.; Ghani, Ma`aruf Abd.

    2014-09-01

    Vibrio vulnificus infections are worldwide public health problems associated with illnesses resulting from consumption of raw or partially cooked seafood. The aim of this study was to investigate the presence and identification of V. vulnificus in cockles from local wet (40) and supermarkets (38) from Selangor, Malaysia from July 2013 to February 2014. A total of 78(n=78) cockle were examined for the presence of V. vulnificus and at about 32% (25/78) cockle samples were positive to this bacterium. Colonies morphological observation and biochemical characterization for those isolates showed 60% (15/78) of isolates were classified as biotype 1 and 40% (10/78) belong to biotype 2.

  2. Memecylon edule leaf extract mediated green synthesis of silver and gold nanoparticles

    PubMed Central

    Elavazhagan, Tamizhamudu; Arunachalam, Kantha D

    2011-01-01

    We used an aqueous leaf extract of Memecylon edule (Melastomataceae) to synthesize silver and gold nanoparticles. To our knowledge, this is the first report where M. edule leaf broth was found to be a suitable plant source for the green synthesis of silver and gold nanoparticles. On treatment of aqueous solutions of silver nitrate and chloroauric acid with M. edule leaf extract, stable silver and gold nanoparticles were rapidly formed. The gold nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infra-red spectroscopy (FTIR). The kinetics of reduction of aqueous silver and gold ions during reaction with the M. edule leaf broth were easily analyzed by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to M. edule leaf broth, were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. TEM analysis of gold nanoparticles showed formation of triangular, circular, and hexagonal shapes in the size range 10–45 nm. The resulting silver nanoparticles were predominantly square with uniform size range 50–90 nm. EDAX results confirmed the presence of triangular nanoparticles in the adsorption peak of 2.30 keV. Further FTIR analysis was also done to identify the functional groups in silver and gold nanoparticles. The characterized nanoparticles of M. edule have potential for various medical and industrial applications. Saponin presence in aqueous extract of M. edule is responsible for the mass production of silver and gold nanoparticles. PMID:21753878

  3. Spatial pattern of early recruitment of Macoma balthica (L.) and Cerastoderma edule (L.) in relation to sediment dynamics on a highly dynamic intertidal sandflat

    NASA Astrophysics Data System (ADS)

    Bouma, H.; Duiker, J. M. C.; de Vries, P. P.; Herman, P. M. J.; Wolff, W. J.

    2001-05-01

    To investigate the possible relationship between sediment dynamics and spatial distribution of early bivalve recruits, a correlative field study was carried out on a highly dynamic intertidal sandflat in the Westerschelde estuary, SW Netherlands. On a spatial grid, 43 plots over an area of 700×800 m 2, early recruits (300-1000 μm mesh fraction) of the tellinid clam Macoma balthica (L.) and the edible cockle Cerastoderma edule (L.) were sampled during the spatfall period (May-June) in 1997. Data were also collected on bed-level height, sediment dynamics and -composition and abundance of adult benthos. The grid covered a range of -50 to +140 cm with respect to mean-tide level. In both species, maximum early recruitment was found at the higher part of this range of intertidal levels. The strong gradient in densities from the lower towards the higher intertidal was significantly negatively correlated with sediment dynamics. No significant correlations of early-recruit densities were found with silt content, or with densities of adult benthos. The relationship between early recruitment and bed-level height differed from that observed in Wadden Sea studies of recruits of similar size, where maximum early recruitment occurred in the lower intertidal. It is suggested that in highly dynamic environments, sediment dynamics may have an important influence on passive resuspension of early recruits and on spatial patterns of early recruitment. Based on field and model data, it is discussed which processes could cause the difference in early recruitment patterns in low and highly dynamic intertidal environments. It is concluded that the presence of low-dynamic areas is essential for the success of early recruitment, and thus for the maintenance of bivalve populations.

  4. Preliminary investigations into the aetiology and treatment of cockle, a sheep pelt defect.

    PubMed

    Heath, A C; Cole, D J; Bishop, D M; Pfeffer, A; Cooper, S M; Risdon, P

    1995-01-01

    A defect of sheep pelts known as cockle, detectable after depilation, but usually first noted only in the pickled pelt or tanned stage of processing, was studied to establish causal factor(s) and effective treatments. In addition, data on the histology and seasonal prevalence of the disease were obtained. Samples collected soon after slaughter from pelts identified at the pickled pelt stage as having cockle, had a superficial dermatitis with infiltration of eosinophils. This may represent an immediate hypersensitivity reaction of the sheep to lice. Treatments of sheep with either insecticides, disinfectants or shearing showed that where biting lice (Bovicola ovis) were removed, cockle lesions had either disappeared or regressed on pickled pelts. In Trial 1 diazinon reduced cockle prevalence and severity substantially; cypermethrin had a less pronounced effect. In Trial 2 diazinon, cypermethrin, Hibitane and Savlon were equally effective in reducing biting louse numbers as shown by counts of lice at 35 and 63 days post-treatment. Reduction of cockle on pelts from sheep slaughtered at 39 days post-treatment was achieved best by both diazinon and shearing. Examination of other pelts at 67 days post-treatment showed diazinon and Hibitane to be equally effective in reducing cockle. Furthermore, shearing in the absence of insecticides reduced the severity and extent of lesions on cockled pelts. The diazinon excipient and zinc sulphate were consistently poor at removing lice and reducing cockle prevalence and severity. The results have important implications for the leather industry in that shearing and good dipping practice with appropriate chemicals at the right time can lead to improved pelt quality. However, an incentive scheme for farmers, and a means of identifying individual pelts to the farms or origin, are both necessary before a marked improvement is likely to occur. PMID:7732648

  5. Low molecular weight squash trypsin inhibitors from Sechium edule seeds.

    PubMed

    Laure, Hélen J; Faça, Vítor M; Izumi, Clarice; Padovan, Júlio C; Greene, Lewis J

    2006-02-01

    Nine chromatographic components containing trypsin inhibitor activity were isolated from Sechium edule seeds by acetone fractionation, gel filtration, affinity chromatography and RP-HPLC in an overall yield of 46% of activity and 0.05% of protein. The components obtained with highest yield of total activity and highest specific activity were sequenced by Edman degradation and their molecular masses determined by mass spectrometry. The inhibitors contained 31, 32 and 27 residues per molecule and their sequences were: SETI-IIa, EDRKCPKILMRCKRDSDCLAKCTCQESGYCG; SETI-IIb, EEDRKCPKILMRCKRDSDCLAKCTCQESGYCG and SETI-V, CPRILMKCKLDTDCFPTCTCRPSGFCG. SETI-IIa and SETI-IIb, which differed by an amino-terminal E in the IIb form, were not separable under the conditions employed. The sequences are consistent with consensus sequences obtained from 37 other inhibitors: CPriI1meCk_DSDCla_C_C_G_CG, where capital letters are invariant amino acid residues and lower case letters are the most preserved in this position. SETI-II and SETI-V form complexes with trypsin with a 1:1 stoichiometry and have dissociation constants of 5.4x10(-11)M and 1.1x10(-9)M, respectively. PMID:16406091

  6. Duplex PCR for detection of Salmonella and Shigella spp in cockle samples.

    PubMed

    Senachai, Pachara; Chomvarin, Chariya; Wongboot, Warawan; Boonyanugomol, Wongwarut; Tangkanakul, Waraluk

    2013-09-01

    Salmonella and Shigella spp are important causative agents of foodborne diseases. A sensitive, specific and rapid method is essential for detection of these pathogens. In this study, a duplex PCR method was developed for simultaneous detection of Salmonella and Shigella spp in cockle samples and compared with the traditional culture method. Enrichment broths for Salmonella spp recovery were also compared. Sensitivity of the duplex PCR for simultaneous detection of Salmonella and Shigella spp from pure culture was 10(3) CFU/ml (40 CFU/PCR reaction), and that of sterile cockle samples spiked with these two pathogens was 1 CFU/10 g of cockle tissue after 9 hours enrichment [3 hours in buffered peptone water (BPW), followed by 6 hours in Rappaport Vasiliadis (RV) broth or tetrathionate (TT) broth for Salmonella spp and 6 hours enrichment in Shigella broth (SB) for Shigella spp]. There was no significant difference in detection sensitivity between enrichment in RV and TT broths. Salmonella spp detected in cockles in Khon Kaen, Thailand by duplex PCR and culture method was 17% and 13%, respectively but Shigella spp was not detected. The duplex PCR technique developed for simultaneous detection of Salmonella and Shigella spp in cockle samples was highly sensitive, specific and rapid and could serve as a suitable method for food safety assessment. PMID:24437322

  7. Properties of cast films made of chayote (Sechium edule Sw.) tuber starch reinforced with cellulose nanocrystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, cellulose (C) and cellulose nanocrystals (CN) were blended with chayote tuber (Sechium edule Sw.) starch (CS) in formulations cast into films. The films were conditioned at different storage temperatures and relative humidity (RH), and analyzed by mechanical tests, X-ray diffraction, ...

  8. Effects of macroalgal mats and hypoxia on burrowing depth of the New Zealand cockle ( Austrovenus stutchburyi)

    NASA Astrophysics Data System (ADS)

    Marsden, Islay D.; Bressington, Melanie J.

    2009-02-01

    Macroalgal mats commonly occur in estuaries and sheltered embayments where they are thought to affect the oxygen conditions in the sediment, influence the geochemical process and influence the burrowing activity of bivalves. Laboratory experiments evaluated the effects of sediment hypoxia and algal mats on the burrowing ability and survival of the New Zealand cockle Austrovenus stutchburyi at 15 °C. Both dissolved oxygen concentration and time affected the burial depth of the cockles over the 12 days of the experiment. In hypoxic conditions (<2 mg L -1), cockles migrated to the sediment surface after 3.5 days and mortality occurred after 11 days. Bivalves exposed to oxygen concentrations of 2-3 mg L -1 buried closer to the sediment surface than those in the other treatments. Using a simulated tidal regime, in a mesocosm, burrowing behaviour of the cockle and pore-water oxygen conditions in the sediment were measured on exposure to experimental mats of Gracilaria chilensis and Ulva spp. for over 6 days. Algal mats on the surface of the sediment significantly lowered the dissolved oxygen concentration of the sediment pore-water and this effect was greater for the Ulva spp. treatment than the G. chilensis treatment. Cockles were buried more deeply in the control treatment without algae than in either of the two algal treatments. It is concluded that reduced oxygen conditions (<3.5 mg L -1) develop under macroalgal mats and that this reduces the burial depth of cockles. The potential harmful effects of the mats can depend on the species forming the mat and these effects are likely to be greater in the field than they are in controlled laboratory conditions.

  9. Seston Dynamics and Food Availability on Mussel and Cockle Beds

    NASA Astrophysics Data System (ADS)

    Smaal, A. C.; Haas, H. A.

    1997-08-01

    To provide a better understanding of seston dynamics in relation to food supply to the benthos, a series of 13-h tidal cycle sampling programmes was executed in the Oosterschelde estuary (The Netherlands). Samples were taken near the surface and near the bottom on two subtidal mussel cultivation plots and on two intertidal cockle beds. Long-term annual variablity of seston concentrations was lower than coefficients of variance of the short-term tidal cycle seston data at the intertidal stations, and higher than at the subtidal stations. Near-bottom relative to surface concentrations were highest for suspended particulate matter (SPM), followed by particulate organic carbon (POC), and chlorophyll. There was no food depletion near the bottom but food quality was lower, presumably due to re-suspension of sediment, including low-quality biodeposits. Chlorophyll concentrations were lower in ebb than flood water at all stations, which was ascribed to feeding activity of the bivalves. At the subtidal stations, SPM and POC concentrations were also lower during low water, owing to sedimentation. There was a positive correlation at the intertidal stations of seston quantity with wind speed and wave action. At a wave length exceeding twice the water depth, re-suspension of low quality bottom material was observed and seston quality decreased. It was concluded that food availability for benthic suspension feeders was lower than suggested by routine monitoring data. At the intertidal stations, food quality was further reduced during periods of increased wind velocities and wave action. The low near-bottom food quality can partly be considered as an effect of the feeding activity of the benthic suspension feeders.

  10. Molecular analysis of Vibrio vulnificus isolated from cockles and patients in Thailand.

    PubMed

    Mala, Wanida; Chomvarin, Chariya; Alam, Munirul; Rashed, Shah M; Faksri, Kiatichai; Angkititrakul, Sunpetch

    2014-01-01

    Vibrio vulnificus can cause septicemia, wound infection and gastroenteritis. The most severe infections are related to consumption of raw or undercooked seafood. Virulence genes, biomarkers, antimicrobial resistance, and genetic relationships among V vulnificus isolated from clinical and environmental sources in Thailand have not hitherto been investigated. ViuB encoding vulnibactin siderophore was detected in 33% and 50% of clinical and environmental (cockle) V. vulnificus isolates, respectively, and capsular polysaccharide allele 1 in 67% and 75% of clinical and environmental isolates, respectively. Analysis of the 16 S rDNA gene revealed that type B was the most frequent in both clinical and environmental isolates (67%) whereas the non type-able (30%) was detected only in environmental isolates. The virulence-correlated gene (vcg) with both type C and E together was the most frequently found among the clinical (67%) and environmental (72%) isolates. Pulsed-field gel electrophoresis differentiated V vulnificus into 2 clusters; most cockle samples (83%) and all clinical isolates grouped into cluster II, indicating a possible clonal relationship between V. vulnificus isolated from patients and cockles. Only 20% of environmental isolates were resistant to ampicillin. These studies suggest that V vulnificus isolated from cockles has virulence genes similar to those in clinical isolates and thus may have the potential of causing disease. PMID:24964659

  11. Determining the geographical origin of Sechium edule fruits by multielement analysis and advanced chemometric techniques.

    PubMed

    Hidalgo, Melisa J; Fechner, Diana C; Marchevsky, Eduardo J; Pellerano, Roberto G

    2016-11-01

    This paper describes the determination and evaluation of the major and trace element composition (Al, As, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Pb, Sr and Zn) of Sechium edule (Jacq) Swartz fruits collected from four different places of production in Corrientes province, Argentina. Element concentrations were determined by using inductively coupled plasma optical emission spectrometry (ICP OES) after microwave digestion. The accuracy was confirmed with standard reference material of spinach leaves (NIST, 1570a) and spiking tests. Principal component analysis (PCA), linear discriminant analysis (LDA), k-nearest neighbors (kNN), partial least square-discriminant analysis (PLS-DA) and support vector machine (SVM) were applied to the results for discriminating the geographical origin of S. edule fruits. Finally, the LDA method was found to perform best with up to 90% accuracy rate based on the following elements: Ca, Ba, Cu, Mn, Na, Sr, and Zn. PMID:27211642

  12. Municipal solid waste compost application improves productivity, polyphenol content, and antioxidant capacity of Mesembryanthemum edule.

    PubMed

    Lakhdar, Abdelbasset; Falleh, Hanen; Ouni, Youssef; Oueslati, Samia; Debez, Ahmed; Ksouri, Riadh; Abdelly, Chedly

    2011-07-15

    Organic wastes were successfully used as soil amendment to improve agrosystems productivity. Yet, the effectiveness of this practice to enhance plant antioxidant capacities has received little attention. Here, we assess the effect of municipal solid waste (MSW) compost (at 40 t ha(-1)) on growth, polyphenol contents and antioxidant activities of Mesembryanthemum edule. MSW compost application significantly increased the soil contents of carbon, nitrogen, calcium, phosphorus and potassium. This was associated with higher nutrient (N, P, and K) uptake, which likely led to the significant improvement of the plant biomass and relative growth rate (RGR) (+93% on average) as compared to the control. In the same way, the fertilizing effect of the added organic matter significantly enhanced the antioxidant potential M. edule, assessed by radical scavenging activity, iron reducing power and β-carotene bleaching capacity. This was associated with significantly higher antioxidant contents, mainly total phenols and flavonoids. Heavy metal (Pb, Cd, Cu, and Zn) concentrations were slightly increased upon compost application, but remained lower than phytotoxic values. Overall, our results point out that short-term MSW compost application at 40 t ha(-1) is efficient in enhancing the productivity together with the antioxidant potentiality of M. edule without any adverse environmental impact. PMID:21605936

  13. Utilization of molecular markers for the conservation of blood cockles, Anadara granosa (Arcidae).

    PubMed

    Chee, S Y; Azizah, M N S; Devakie, M N

    2011-01-01

    We examined genetic variation in blood cockles in an effort to obtain information useful for the sustainability, management, and the stability of this species as a major commodity in the fisheries sector. Ten populations of cockles were sampled from the north to the south of the west coast of peninsular Malaysia. The cockles were collected in collaboration with the Fisheries Research Institute, Penang. The population genetic analysis of the cockles were studied via RAPD-PCR and mtDNA sequencing. Three hundred individuals were analyzed with RAPD-PCR experiments. High gene diversity over all loci was observed (Shannon index = 0.549 ± 0.056 and Nei's gene diversity = 0.4852 ± 0.0430 among 35 loci). The second method, mtDNA sequencing, was employed to complement the information obtained from RAPD-PCR. The gene selected for mtDNA sequencing was cytochrome c oxidase I (COI). One hundred and fifty individuals were sequenced, yielding a partial gene of 585 bp. Statistical analysis showed homogeneity in general but did reveal some degree of variability between the populations in Johor and the rest of the populations. The Mantel test showed a positive but nonsignificant correlation between geographic and genetic distances (r = 0.2710, P = 0.622), as in the RAPD analysis. We propose that the homogeneity between distant populations is caused by two factors: 1) the translocation of the spats; 2) larvae are carried by current movement from the north of the peninsula to the south. The different genetic composition found in Johor could be due to pollution, mutagenic substances or physical factors such as the depth of the water column. This population genetic study is the first for this species in peninsular Malaysia. The data from this study have important implications for fishery management, conservation of blood cockles and translocation policies for aquaculture and stock enhancement programs. PMID:21732289

  14. Serogroup, virulence, and molecular traits of Vibrio parahaemolyticus isolated from clinical and cockle sources in northeastern Thailand.

    PubMed

    Mala, Wanida; Alam, Munirul; Angkititrakul, Sunpetch; Wongwajana, Suwin; Lulitanond, Viraphong; Huttayananont, Sriwanna; Kaewkes, Wanlop; Faksri, Kiatichai; Chomvarin, Chariya

    2016-04-01

    Vibrio parahaemolyticus is responsible for seafood-borne gastroenteritis worldwide. Isolates of V. parahaemolyticus from clinical samples (n=74) and cockles (Anadara granosa) (n=74) in Thailand were analyzed by serotyping, determination of virulence and related marker genes present, response to antimicrobial agents, and genetic relatedness. Serological analysis revealed 31 different serotypes, 10 of which occurred among both clinical and cockle samples. The clinical isolates commonly included the pandemic serogroup O3:K6, while a few of the cockle isolates exhibited likely pandemic serovariants such as O3:KUT and O4:KUT, but not O3:K6. The pandemic (orf8 gene-positive) strains were more frequently found among clinical isolates (78.4%) than cockle isolates (28.4%) (p<0.001). Likewise, the virulence and related marker genes were more commonly detected among clinical than cockle isolates; i.e., tdh gene (93.2% versus 29.7%), vcrD2 (97.3% versus 23.0%), vopB2 (89.2% versus 13.5%), vopT (98.6% versus 36.5%) (all p<0.001) and trh (10.8% versus 1.4%) (p<0.05). Pulsed-field gel electrophoresis of NotI-digested genomic DNA of 41 randomly selected V. parahaemolyticus isolates representing different serotypes produced 33 pulsotypes that formed 5 different clusters (clonal complexes) (A-E) in a dendrogram. Vibrio parahaemolyticus O3:K6 and likely related pandemic serotypes were especially common among the numerous clinical isolates in cluster C, suggesting a close clonal link among many of these isolates. Most clinical and cockle isolates were resistant to ampicillin. This study indicates that O3:K6 and its likely serovariants based on the PFGE clusters, are causative agents. Seafoods such as cockles potentially serve as a source of virulent V. parahaemolyticus, but further work is required to identify possible additional sources. PMID:26773828

  15. The inhibitory effect of Mesembryanthemum edule (L.) bolus essential oil on some pathogenic fungal isolates

    PubMed Central

    2014-01-01

    Background Mesembryanthemum edule is a medicinal plant which has been indicated by Xhosa traditional healers in the treatment HIV associated diseases such as tuberculosis, dysentery, diabetic mellitus, laryngitis, mouth infections, ringworm eczema and vaginal infections. The investigation of the essential oil of this plant could help to verify the rationale behind the use of the plant as a cure for these illnesses. Methods The essential oil from M. edule was analysed by GC/MS. Concentration ranging from 0.005 - 5 mg/ml of the hydro-distilled essential oil was tested against some fungal strains, using micro-dilution method. The plant minimum inhibitory activity on the fungal strains was determined. Result GC/MS analysis of the essential oil resulted in the identification of 28 compounds representing 99.99% of the total essential oil. A total amount of 10.6 and 36.61% constituents were obtained as monoterpenes and oxygenated monoterpenes. The amount of sesquiterpene hydrocarbons (3.58%) was low compared to the oxygenated sesquiterpenes with pick area of 9.28%. Total oil content of diterpenes and oxygenated diterpenes detected from the essential oil were 1.43% and 19.24%. The fatty acids and their methyl esters content present in the essential oil extract were found to be 19.25%. Antifungal activity of the essential oil extract tested against the pathogenic fungal, inhibited C. albican, C. krusei, C. rugosa, C. glabrata and C. neoformans with MICs range of 0.02-0.31 mg/ml. the activity of the essential oil was found competing with nystatin and amphotericin B used as control. Conclusion Having accounted the profile chemical constituent found in M. edule oil and its important antifungal properties, we consider that its essential oil might be useful in pharmaceutical and food industry as natural antibiotic and food preservative. PMID:24885234

  16. Effect of salt treatment on phenolic compounds and antioxidant activity of two Mesembryanthemum edule provenances.

    PubMed

    Falleh, Hanen; Jalleli, Inès; Ksouri, Riadh; Boulaaba, Mondher; Guyot, Sylvain; Magné, Christian; Abdelly, Chedly

    2012-03-01

    Mesembryanthemum edule L. is an edible and medicinal halophyte widespread in Tunisia seashore. In this study, parameters of oxidative stress, phenolic compounds and antioxidant activities were comparatively investigated in two M. edule provenances (Jerba and Bizerte, respectively sampled from arid and humid bioclimatic stages). Plants were subjected to 0, 300 and 600mM NaCl treatment under glasshouse conditions. Results showed that M. edule response to salinity depends on provenance (P), salt treatment (T) and their interaction (P×T). (T) affected more significantly the oxidative stress parameters and antioxidant activities than (P) and (P×T). Conversely, (P) was much affluent for tannin polymerization degree and interaction between the two factors (P×T) was more determinants for analyzed antioxidant parameters. The higher salt tolerance of Jerba plants was associated with low levels of malondialdehyde and of electrolyte leakage mainly at 600mM NaCl. Besides, antioxidant activities of Jerba provenance, were more efficient than Bizerte. In addition, avicularin was the major phenolic in both provenances. This compound concentration increased with salinity in Jerba shoots, while it was reduced in Bizerte especially at 600mM NaCl. Overall, the higher salt tolerance of plants from Jerba provenance, and to a lower extent of those from Bizerte, may be partly related to their better capacity to limit oxidative damage when salt-challenged, and this is likely the result of redistribution in phenolic composition. Besides, abiotic factors such as salinity could be determinant in antioxidant potentiality of this medicinal plant. PMID:22305062

  17. Application of tetraplex PCR for detection of Vibrio cholerae, V. parahaemolyticus, V. vulnificus and V. mimicus in cockle.

    PubMed

    Senachai, Pachara; Chomvarin, Chariya; Namwat, Wises; Wongboot, Warawan; Wongwajana, Suwin; Tangkanakul, Waraluk

    2013-03-01

    A tetraplex PCR method was developed for simultaneous detection of Vibrio cholerae, V. parahaemolyticus, V. vulnificus and V. mimicus in cockle samples in comparison with conventional culture method. Specific primers targeting ompW of V. cholerae, tl of V. parahaemolyticus, hsp60 of V. vulnificus and sodB of V. mimicus were employed in the same PCR. Detection limit of the tetraplex PCR assay was 104 cfu/ml (400 cfu/PCR reaction) for pure cultures of all four species of Vibrio. In Vibrio spiked cockle samples, the limit of detection after 6 hours enrichment in alkaline peptone water was 1 cfu/10 g of cockle tissue for three Vibrio spp, except for V. mimicus that was 102 cfu/10 g of cockle tissue. When the tetraplex PCR and culture methods were applied to 100 cockle samples, V. parahaemolyticus, V. vulnificus, V. cholerae and V. mimicus were detected in 100, 98, 80 and 9% of the samples by tetraplex PCR and in 76, 42, 0 and 0% by the culture method, respectively. This developed tetraplex PCR method should be suitable for simultaneous and rapid detection of Vibrio species in food samples and for food safety assessment. PMID:23691635

  18. Evaluation of the potential bioaccumulation ability of the blood cockle (Anadara granosa L.) for assessment of environmental matrices of mudflats.

    PubMed

    Mirsadeghi, Seiedeh Aghileh; Zakaria, Mohamad Pauzi; Yap, Chee Kong; Gobas, Frank

    2013-06-01

    The spatial distribution of 19 polycyclic aromatic hydrocarbons (tPAHs) was quantified in aquacultures located in intertidal mudflats of the west coast of Peninsular Malaysia in order to investigate bioaccumulation of PAH in blood cockles, Anadara granosa (A. granosa). Fifty-four samples from environmental matrices and A. granosa were collected. The sampling locations were representative of a remote area as well as PAH-polluted areas. The relationship of increased background levels of PAH to anthropogenic PAH sources in the environment and their effects on bioaccumulation levels of A. granosa are investigated in this study. The levels of PAH in the most polluted station were found to be up to ten-fold higher than in remote areas in blood cockle. These high concentrations of PAHs reflected background contamination, which originates from distant airborne and waterborne transportation of contaminated particles. The fraction and source identification of PAHs, based on fate and transport considerations, showed a mix of petrogenic and pyrogenic sources. The relative biota-sediment accumulation factors (RBSAF), relative bioaccumulation factors from filtered water (RBAFw), and from suspended particulate matter (SPM) (RBAFSP) showed higher bioaccumulations of the lower molecular weight of PAHs (LMWs) in all stations, except Kuala Juru, which showed higher bioaccumulation of the higher molecular weight of PAHs (HMWs). Calculations of bioaccumulation factors showed that blood cockle can accumulate PAHs from sediment as well as water samples, based on the physico-chemical characteristics of habitat and behaviour of blood cockles. Correlations among concentrations of PAHs in water, SPM, sediment and A. granosa at the same sites were also found. Identification of PAH levels in different matrices showed that A. granosa can be used as a good biomonitor for LMW of PAHs and tPAHs in mudflats. Considering the toxicity and carcinogenicity of PAHs, the bioaccumulation by blood cockles

  19. Prevalence and Molecular Genotyping of Noroviruses in Market Oysters, Mussels, and Cockles in Bangkok, Thailand.

    PubMed

    Kittigul, Leera; Thamjaroen, Anyarat; Chiawchan, Suwat; Chavalitshewinkoon-Petmitr, Porntip; Pombubpa, Kannika; Diraphat, Pornphan

    2016-06-01

    Noroviruses are the most common cause of acute gastroenteritis associated with bivalve shellfish consumption. This study aimed to detect and characterize noroviruses in three bivalve shellfish species: oysters (Saccostrea forskali), cockles (Anadara nodifera), and mussels (Perna viridis). The virus concentration procedure (adsorption-twice elution-extraction) and a molecular method were employed to identify noroviruses in shellfish. RT-nested PCR was able to detect known norovirus GII.4 of 8.8 × 10(-2) genome copies/g of digestive tissues from oyster and cockle concentrates, whereas in mussel concentrates, the positive result was seen at 8.8 × 10(2) copies/g of digestive tissues. From August 2011 to July 2012, a total of 300 shellfish samples, including each of 100 samples from oysters, cockles, and mussels were collected and tested for noroviruses. Norovirus RNA was detected in 12.3 % of shellfish samples. Of the noroviruses, 7.7 % were of the genogroup (G) I, 2.6 % GII, and 2.0 % were mixed GI and GII. The detection rate of norovirus GI was 2.1 times higher than GII. With regards to the different shellfish species, 17 % of the oyster samples were positive, while 14.0 and 6.0 % were positive for noroviruses found in mussels and cockles, respectively. Norovirus contamination in the shellfish occurred throughout the year with the highest peak in September. Seventeen norovirus-positive PCR products were characterized upon a partial sequence analysis of the capsid gene. Based on phylogenetic analysis, five different genotypes of norovirus GI (GI.2, GI.3, GI.4, GI.5, and GI.9) and four different genotypes of GII (GII.1, GII.2, GII.3, and GII.4) were identified. These findings indicate the prevalence and distribution of noroviruses in three shellfish species. The high prevalence of noroviruses in oysters contributes to the optimization of monitoring plans to improve the preventive strategies of acute gastroenteritis. PMID:26872638

  20. In Vivo Gibberellin Biosynthesis in Endosperm of Sechium edule Sw. Seeds

    PubMed Central

    Ceccarelli, Nello; Lorenzi, Roberto

    1990-01-01

    Biosynthesis of gibberellins (GAs) was studied in vivo in endosperms of Sechium edule Sw. Exogenous ent-[14C]kaurene was metabolized into four major products: GA12, GA4, GA7 and 16, 17-dihydro-16-hydroxy-GA15 alcohol glucoside. Other minor metabolites were also observed including ent-kaurenol and ent-kaurenal. Conversion of ent-[14C]kaurene to ent-kaurenol glucoside by endosperm cell-free preparations in the presence of UDPG was observed. However, the finding was not confirmed in in vivo studies and is probably artifactual. Overall evidence coming from the analysis of endogenous GAs and in vitro and in vivo biosynthetic studies are discussed in relation to the possible existence in the Sechium seeds of a different route, along with the known pathway, branching from ent-kaurene or ent-7-α-hydroxykaurenoic acid and this also leading to biologically active GAs. PMID:16667553

  1. Impact of high pCO2 on shell structure of the bivalve Cerastoderma edule.

    PubMed

    Milano, Stefania; Schöne, Bernd R; Wang, Schunfeng; Müller, Werner E

    2016-08-01

    Raised atmospheric emissions of carbon dioxide (CO2) result in an increased ocean pCO2 level and decreased carbonate saturation state. Ocean acidification potentially represents a major threat to calcifying organisms, specifically mollusks. The present study focuses on the impact of elevated pCO2 on shell microstructural and mechanical properties of the bivalve Cerastoderma edule. The mollusks were collected from the Baltic Sea and kept in flow-through systems at six different pCO2 levels from 900 μatm (control) to 24,400 μatm. Extreme pCO2 levels were used to determine the effects of potential leaks from the carbon capture and sequestration sites where CO2 is stored in sub-seabed geological formations. Two approaches were combined to determine the effects of the acidified conditions: (1) Shell microstructures and dissolution damage were analyzed using scanning electron microscopy (SEM) and (2) shell hardness was tested using nanoindentation. Microstructures of specimens reared at different pCO2 levels do not show significant changes in their size and shape. Likewise, the increase of pCO2 does not affect shell hardness. However, dissolution of ontogenetically younger portions of the shell becomes more severe with the increase of pCO2. Irrespective of pCO2, strong negative correlations exist between microstructure size and shell mechanics. An additional sample from the North Sea revealed the same microstructural-mechanical interdependency as the shells from the Baltic Sea. Our findings suggest that the skeletal structure of C. edule is not intensely influenced by pCO2 variations. Furthermore, our study indicates that naturally occurring shell mechanical property depends on the shell architecture at μm-scale. PMID:27285613

  2. Effects of environmental and physiological variables on the accumulated concentrations of trace metals in the New Zealand cockle Austrovenus stutchburyi.

    PubMed

    Marsden, Islay D; Smith, Brian D; Rainbow, Phillip S

    2014-02-01

    We examined potential causes of variation in trace element accumulation in an estuarine bivalve Austrovenus stutchburyi from two estuarine systems in South Island, New Zealand which differed in their metal contamination and salinity regimes. Concentrations of Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn were measured (ICP-OES) in whole body tissues of bivalves collected from 10 sites, seston collected at high tide (a potential food resource) and in the sediment at the sites. All 13 elements showed a relationship between log bioaccumulated trace element concentration (mgkg(-1) dry weight tissue) and log shell length (mm), either in the whole data set or at least one site (ANCOVA). Growth rates of cockles varied significantly amongst sites. Accumulated soft tissue concentrations of Ag, As, Co and Cr increased with age of cockle, those of Pb and Zn decreased, with no clear age-related trend for the remaining metals (ANCOVA). Shell length was generally a good proxy for age when allowing for any size effect in metal accumulation by the cockle. There was no consistent pattern between the estuarine systems, probably reflecting unidentified contaminant inputs. Following depuration, tissue concentrations decreased significantly for some elements (Fe, Mn, Ti and V), indicating high concentrations of these metals in the gut contents. Trace element concentrations in the seston generally did not correlate with the bivalve tissue concentrations. There were few (Spearman's Rank) correlations between environmental variables at the time of sampling and cockle tissue trace element concentrations. The main sources of variation in bioaccumulated trace metal concentrations in the whole tissues of the cockle are location, shell length and age. PMID:24144937

  3. The polyphenol extract from Sechium edule shoots inhibits lipogenesis and stimulates lipolysis via activation of AMPK signals in HepG2 cells.

    PubMed

    Wu, Cheng-Hsun; Ou, Ting-Tsz; Chang, Chun-Hua; Chang, Xiao-Zong; Yang, Mon-Yuan; Wang, Chau-Jong

    2014-01-22

    Fatty liver may have implications for metabolic syndrome, such as obesity, hypertension, and diabetes. Therefore, the development of pharmacological or natural agents to reduce fat accumulation in the liver is an important effort. The Sechium edule shoots have already been verified to decrease serum lipids and cholesterol and prevent atherosclerosis. However, how Sechium edule shoots modulate hepatic lipid metabolism is unclear. This study was designed to investigate the effects and mechanisms of polyphenol extracts (SPE) of Sechium edule shoots in reducing lipid accumulation in oleic acid-treated HepG2 cells. We found that water extracts (SWE) of Sechium edule shoots could decrease serum and hepatic lipid contents (e.g., triacylglycerol and cholesterol). Furthermore, SWE and SPE through the AMPK (AMP-activating protein kinase) signaling pathway could decrease lipogenic relative enzymes, such as FAS (fatty acid synthase), HMGCoR (HMG-CoA reductase), and SREBPs (sterol regulatory element binding proteins), and increase the expression of CPT-I (carnitine palmitoyltransferase I) and PPARα (peroxisome proliferators activated receptor α), which are critical regulators of hepatic lipid metabolism. These observations suggested that Sechium edule shoots have potential for developing health foods for preventing and remedying fatty liver. PMID:24377368

  4. Malaysian cockle (Anadara granosa) allergy: Identification of IgE-binding proteins and effects of different cooking methods.

    PubMed

    Zailatul, H M Y; Rosmilah, M; Faizal, B; Noormalin, A; Shahnaz, M

    2015-06-01

    The purpose of this study was to evaluate the effect of different cooking methods on the allergenicity of cockle and to identify proteins most frequently bound by IgE antibodies using a proteomics approach. Raw, boiled, fried and roasted extracts of the cockle were prepared. The protein profiles of the extracts were obtained by separation using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional gel electrophoresis (2-DE). IgE-immunoblotting was then performed with the use of individual sera from patients with cockle allergy and the major IgE-binding proteins were analyzed by mass-spectrometry. SDS-PAGE of raw extract showed 13 protein bands. Smaller numbers of protein bands were detected in the boiled, fried and roasted extracts. The 2-DE gel profile of the raw extract further separated the protein bands to ~50 protein spots with molecular masses between 13 to 180 kDa and isoelectric point (pI) values ranging from 3 to 10. Immunoblotting of raw extract exhibited 11 IgE-binding proteins with two proteins of 36 and 40 kDa as the major IgE-binding proteins, while the boiled extract revealed 3 IgE-binding proteins. Fried and roasted extracts only showed a single IgE-binding protein at 36 kDa. 2-DE immunoblotting of raw extract demonstrated 5 to 20 IgE reactive spots. Mass spectrometry analysis led to identification of 2 important allergens, tropomyosin (36 kDa) and arginine kinase (40 kDa). Heated extracts showed a reduction in the number of IgE-reactive bands compared with raw extract, which suggest that thermal treatment can be used as a tool in attempting to reduce cockle allergenicity. The degree of allergenicity of cockle was demonstrated in the order raw > boiled > fried ≈ roasted. Two important allergens reacting with more than 50% of patients' sera identified using mass spectrometric approaches were tropomyosin and arginine kinase. Thus, allergens found in this study would help in component based diagnosis, management of

  5. Ultrastructure of the spermatogenesis of the cockle Anadara granosa L. (Bivalvia: Arcidae)

    NASA Astrophysics Data System (ADS)

    Suwanjarat, J.

    1999-11-01

    In this paper spermatogenesis and sperm ultrastructure of the cockle Anadara granosa are studied using transmission electron microscopy. The spermatocyte presents electron-dense vesicles and the arising axoneme that begins to form the flagellum. During spermatid differentiation, proacrosomal vesicles appear to migrate towards the presumptive anterior pole of the nucleus; eventually these vesicles become acrosome. The spermatozoon of Anadara granosa is of the primitive type. The acrosome, situated at the apex of the nucleus, is cap-shaped and deeply invaginated at the inner side. The spherical nucleus of the spermatozoon contains dense granular chromatin and shows invagination at the posterior poles. The centriole shows the classic nine triplets of microtubules. The middle piece consists of the centriolar complex surrounded by five giant mitochondria. It is shown that the ultrastructure of spermatozoa and spermiogenesis of Anadara granosa reveals a number of features that are common among bivalves.

  6. Cadmium and Lead in Blood Cockle (Anadara granosa) from Asajaya, Sarawak, Malaysia

    PubMed Central

    Hossen, Md. Faruk; Hamdan, Sinin; Rahman, Md. Rezaur

    2014-01-01

    The concentrations were ranged from 1.35 ± 0.16 to 2.22 ± 0.34 µg/g (dry weight) and 2.65 ± 0.34 to 4.36 ± 0.53 µg/g (dry weight) for Cd and Pb, respectively, in blood cockle Anadara granosa from four sites of Sabang River, namely, Kampung Sambir, Kampung Tambirat, Beliong Temple, and Kampung Tanjung Apong, which are located at Asajaya, Sarawak, Malaysia. All values exceeded safety limits set by Malaysian Food Regulation (1985). It may be the cause of serious human health problems after long term consumption. Thus, consumer should have consciousness about such type of seafood from mentioned sites and need further investigation. PMID:25538965

  7. Corrosion behavior of lacquered tinplate cans in contact with cockles (cardium edulis) in brine solution

    SciTech Connect

    Bastidas, J.M.; Cabanes, J.M.; Catala, R.

    2000-04-01

    Tinplate cans internally coated with an epoxyphenolic plus zinc oxide (ZnO) lacquer were studied. The relationship between lacquer adhesion and total chromium, metallic chromium, and chromium oxide (CrO{sub x}) in the passivated layer was analyzed. The thickness of the CrO{sub x} layer is a controlling parameter of adhesion. Electrochemical impedance spectroscopy (EIS), direct current (DC) polarization, and atomic absorption (AA) experiments were conducted at different time periods up to 150 days. EIS, DC, and AA results indicated that the passivation treatment with the lowest chromium content (Type 1) showed slightly worse corrosion behavior, with substantial iron dissolution and sulfur staining of the tinplate, than passivation treatments Types 2 and 3, which behaved similarly to each other. A fully opened can was used as the working electrode and electrolytic cell in contact with canned cockles (a mollusc, Cardium edulis).

  8. Cadmium and lead in blood cockle (Anadara granosa) from Asajaya, Sarawak, Malaysia.

    PubMed

    Hossen, Md Faruk; Hamdan, Sinin; Rahman, Md Rezaur

    2014-01-01

    The concentrations were ranged from 1.35 ± 0.16 to 2.22 ± 0.34 µg/g (dry weight) and 2.65 ± 0.34 to 4.36 ± 0.53 µg/g (dry weight) for Cd and Pb, respectively, in blood cockle Anadara granosa from four sites of Sabang River, namely, Kampung Sambir, Kampung Tambirat, Beliong Temple, and Kampung Tanjung Apong, which are located at Asajaya, Sarawak, Malaysia. All values exceeded safety limits set by Malaysian Food Regulation (1985). It may be the cause of serious human health problems after long term consumption. Thus, consumer should have consciousness about such type of seafood from mentioned sites and need further investigation. PMID:25538965

  9. Transcriptional response of stress-regulated genes to industrial effluent exposure in the cockle Cerastoderma glaucum.

    PubMed

    Karray, Sahar; Tastard, Emmanuelle; Moreau, Brigitte; Delahaut, Laurence; Geffard, Alain; Guillon, Emmanuel; Denis, Françoise; Hamza-Chaffai, Amel; Chénais, Benoît; Marchand, Justine

    2015-11-01

    This study assessed the responses of molecular biomarkers and heavy metal levels in Cerastoderma glaucum exposed for 1 week to two industrial effluents (1%) discharged into the Tunisian coastal area, F1 and F2, produced by different units of production of a phosphate treatment plant. A significant uptake of metals (Cd, Cu, Zn, and Ni) was observed in exposed cockles compared to controls, with an uptake higher for F1 than for F2. A decrease in LT50 (stress on stress test) was also observed after an exposure to the effluent F1. Treatments resulted in different patterns of messenger RNA (mRNA) expression of the different genes tested in this report. Gene transcription monitoring performed on seven genes potentially involved in the tolerance to metal exposure showed that for both exposures, mechanisms are rapidly and synchronically settled down to prevent damage to cellular components, by (1) handling and exporting out metal ions through the up-regulation of ATP-binding cassette xenobiotic transporter (ABCB1) and metallothionein (MT), (2) increasing the mRNA expression of antioxidant enzymes (catalase (CAT), superoxide dismutases, CuZnSOD and MnSOD), (3) protecting and/or repairing proteins through the expression of heat shock protein 70 (HSP70) mRNAs, and (4) increasing ATP production (through the up-regulation of cytochrome c oxidase 1 (CO1)) to provide energy for cells to tolerate stress exposure. The tools developed may be useful both for future control strategies and for the use of the cockle C. glaucum as a sentinel species. PMID:25613800

  10. In vivo gibberellin biosynthesis in endosperm of Sechium edule Sw. seeds

    SciTech Connect

    Ceccarelli, N.; Lorenzi, R. )

    1990-07-01

    Biosynthesis of gibberellins (GAs) was studied in vivo in endosperms of Sechium edule Sw. Exogenous ent-({sup 14}C)kaurene was metabolized into four major products: GA{sub 12}, GA{sub 4}, GA{sub 7} and 16,17-dihydro-16-hydroxy-GA{sub 15} alcohol glucoside. Other minor metabolites were also observed including ent-kaurenol and ent-kaurenal. Conversion of ent-({sup 14}C)kaurene to ent-karuenol glucoside by endosperm cell-free preparations in the presence of UDPG was observed. However, the finding was not confirmed in in vivo studies and is probably artifactual. Overall evidence coming from the analysis of endogenous GAs and in vitro and in vivo biosynthetic studies are discussed in relation to the possible existence in the Sechium seeds of a different route, along with the known pathway, branching from ent-kaurene or ent-7-{alpha}-hydroxykaurenoic acid and this also leading to biologically active GAs.

  11. Extracts and Fractions from Edible Roots of Sechium edule (Jacq.) Sw. with Antihypertensive Activity

    PubMed Central

    Lombardo-Earl, Galia; Roman-Ramos, Rubén; Zamilpa, Alejandro; Herrera-Ruiz, Maribel; Rosas-Salgado, Gabriela; Tortoriello, Jaime; Jiménez-Ferrer, Enrique

    2014-01-01

    Sechium edule is traditionally used in Mexico as a therapeutic resource against renal diseases and to control high blood pressure. The purpose of this work is to evaluate the antihypertensive effect of the hydroalcoholic extract obtained from the roots of this plant, including its fractions and subfractions, on different hypertension models induced with angiotensin II (AG II). The hydroalcoholic extract was tested on an in vitro study of isolated aorta rings denuded of endothelial cells, using AG II as the agonist; this assay proved the vasorelaxant effect of this extract. Vagotomized rats were administered different doses of AG II as well as the Hydroalcoholic extract, which reduced blood pressure in 30 mmHg approximately; subsequently this extract was separated into two fractions (acetone and methanol) which were evaluated in the acute hypertension mouse model induced with AG II, where the acetone fraction was identified as the most effective one and was subsequently subfractioned using an open chromatographic column packed with silica gel. The subfractions were also evaluated in the acute hypertension model. Finally, the extract, fraction, and active subfraction were analyzed by MS-PDA-HPLC, identifying cinnamic derivative compounds like cinnamic acid methyl ester. PMID:24812568

  12. Extracts and Fractions from Edible Roots of Sechium edule (Jacq.) Sw. with Antihypertensive Activity.

    PubMed

    Lombardo-Earl, Galia; Roman-Ramos, Rubén; Zamilpa, Alejandro; Herrera-Ruiz, Maribel; Rosas-Salgado, Gabriela; Tortoriello, Jaime; Jiménez-Ferrer, Enrique

    2014-01-01

    Sechium edule is traditionally used in Mexico as a therapeutic resource against renal diseases and to control high blood pressure. The purpose of this work is to evaluate the antihypertensive effect of the hydroalcoholic extract obtained from the roots of this plant, including its fractions and subfractions, on different hypertension models induced with angiotensin II (AG II). The hydroalcoholic extract was tested on an in vitro study of isolated aorta rings denuded of endothelial cells, using AG II as the agonist; this assay proved the vasorelaxant effect of this extract. Vagotomized rats were administered different doses of AG II as well as the Hydroalcoholic extract, which reduced blood pressure in 30 mmHg approximately; subsequently this extract was separated into two fractions (acetone and methanol) which were evaluated in the acute hypertension mouse model induced with AG II, where the acetone fraction was identified as the most effective one and was subsequently subfractioned using an open chromatographic column packed with silica gel. The subfractions were also evaluated in the acute hypertension model. Finally, the extract, fraction, and active subfraction were analyzed by MS-PDA-HPLC, identifying cinnamic derivative compounds like cinnamic acid methyl ester. PMID:24812568

  13. Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

    PubMed

    Marques, Ana; Piló, David; Araújo, Olinda; Pereira, Fábio; Guilherme, Sofia; Carvalho, Susana; Santos, Maria Ana; Pacheco, Mário; Pereira, Patrícia

    2016-05-01

    The chronic exposure of benthic organisms to metals in sediments can lead to the development of tolerance mechanisms, thus diminishing their responsiveness. This study aims to evaluate the accumulation profiles of V, Cr, Co, Ni, As, Cd, Pb and Hg and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were collected at the Tagus estuary, in two sites with distinct contamination degrees (ALC, slightly contaminated; BAR, highly contaminated). Accordingly, C. edule accumulated higher concentrations of As, Pb and Hg at BAR compared to ALC. However, antioxidant responses of C. edule were almost unaltered at BAR and no peroxidative damage occurred, suggesting adjustment mechanisms to the presence of metals. In contrast, N. hombergii showed a minor propensity to metal accumulation, only signalising spatial differences for As and Pb and accumulating lower concentrations of metals than C. edule. The differences in metal accumulation observed between species might be due to their distinctive foraging behaviour and/or the ability of N. hombergii to minimise the metal uptake. Despite that, the accumulation of As and Pb was on the basis of the polychaete antioxidant defences inhibition at BAR, including CAT, SOD, GR and GPx. The integrated biomarker response index (IBRv2) confirmed that N. hombergii was more affected by metal exposure than C. edule. In the light of current findings, in field-based studies, the information of C. edule as a bioindicator should be complemented by that provided by another benthic species, since tolerance mechanisms to metals can hinder a correct diagnosis of sediment contamination and of the system's health. Overall, the present study contributed to improve the lack of fundamental knowledge of two widespread and common estuarine species, providing

  14. Hemiuroid trematode sporocysts are undetected by hemocytes of their intermediate host, the ark cockle Anadara trapezia: potential role of surface carbohydrates in successful parasitism.

    PubMed

    Kawasaki, Minami; Delamare-Deboutteville, Jerome; Dang, Cecile; Barnes, Andrew C

    2013-12-01

    In order to establish a successful relationship with their hosts, parasites must subvert or evade immune defences. Cockle Anadara trapezia and Sydney Rock oyster (SRO) Saccostrea glomerata live in the same location but only ark cockles are infected by sporocysts of hemiuroid trematode. This provides an opportunity to explore differing interactions between the parasite and the immune system of susceptible and refractive hosts. Rapid migration and encapsulation of sporocysts was observed by SRO hemocytes but not by cockle hemocytes. This migration/encapsulation was inhibited by N-acetylglucosamine or N-acetylgalactosamine but not by the other sugars, implicating specific surface carbohydrates in immune detection. Effector responses of hemocytes were investigated in vitro in terms of production of reactive oxygen production (ROS). Hemocytes of both species strongly reacted to Zymosan, but only SRO hemocytes responded to live sporocysts. Neither species' hemocytes produced ROS in the presence of dead/fixed sporocysts, and there was no suppression of Zymosan-induced respiratory burst by sporocysts. This suggests that immune escape is mediated by avoiding encapsulation, perhaps through molecular mimicry. Membrane-shaving with proteases indicated that sporocyst surface proteins are not a key factors in hemocytic detection. Surface carbohydrates of SRO and cockle hemocytes and of sporocysts were profiled with a panel of biotinylated lectins. This revealed substantial differences between cockle and SRO hemocytes, but greater similarity between cockle hemocytes and sporocysts. Results suggest that surface carbohydrates play an integral role in hemocyte immunorecognition and that surface carbohydrate molecular mimicry is a potential strategy for immune evasion in cockles by hemiuroid trematode sporocysts. PMID:24161777

  15. Subcellular partitioning of elements and availability for trophic transfer: Comparison between the Bivalve Cerastoderma edule and the Polychaete Diopatra neapolitana

    NASA Astrophysics Data System (ADS)

    Freitas, Rosa; Pires, Adília; Quintino, Victor; Rodrigues, Ana Maria; Figueira, Etelvina

    2012-03-01

    Metal transference through food-chain can constitute a serious problem, particularly in coastal systems, where macrobenthic organisms are often exposed to metal contamination. Previous studies have shown that the elements accumulated in macrobenthic organisms can either be precipitated or soluble in the cells. Whilst differences in the subcellular distribution between fractions are described for Cd, Cu and Zn, little is known for other elements such as As, Pb or Hg, despite their toxicity. The present study compared the subcellular partitioning of several elements in two different macrobenthic species, the bivalve Cerastoderma edule and the polychaete Diopatra neapolitana, and the potential that each element has to be trophically available was determined. There were differences in element accumulation between the two species: D. neapolitana presented a higher concentration of Zn and As while, C. edule accumulated more Al, Ni and Pb. The results obtained for the soluble fraction showed that the elements in higher concentration were, for both species, Al and Zn. In addition to these two elements, Cu, Cd, Cr and As concentrations in this fraction were higher in D. neapolitana than in C. edule, although the bivalve presented higher Ni levels. These results give a good estimate of the amount of elements more readily available to be trophically transferred. The relative amount of metal present in the soluble fraction may indicate more clearly the ability of each species to cope with each element and thus their propensity to allocate subcellular elements, regardless of the environment that it inhabits. The percentage of elements in the soluble fraction showed that C. edule had a high predisposition to compartmentalise As and Cd in the trophically available fraction, given that the other elements were preferentially in the insoluble fraction. In contrast, D. neapolitana distributes metals and As more evenly throughout both fractions. As our study simultaneously evaluated

  16. Phylogenetic study and barcoding of the blood cockle, Tegillarca granosa, found on the west coast of peninsular Malaysia using the COI gene.

    PubMed

    Chee, S Y; Devakie, M N; Siti Azizah, M N

    2011-01-01

    Blood cockles are among the most economically important brackish water invertebrates found in Malaysia. However, our knowledge of blood cockle phylogeny and systematics is rudimentary, especially for the species Tegillarca granosa. It is unclear, for instance, whether the cockles occurring on the west coast of peninsular Malaysia constitute a single species, or multiple, phylogenetically distinct species. We performed the first DNA molecular phylogenetic analysis of T. granosa to distinguish it from other related species found in other parts of the world and to create a DNA database for the species. An approximately 585-nucleotide fragment of the mitochondrial DNA (cytochrome oxidase I, COI) was sequenced for 150 individual cockles, representing 10 populations: three from the north, four from the central part and three from the southern part of peninsular Malaysia. Phylogenetic analyses of the resulting dataset yielded tree topologies that not only showed the relationship between T. granosa and its closest relatives but its position in the evolutionary tree. Three mitochondrial clades were evident, each containing an individual genus. Using the mutation rate of the COI gene, the divergence time between T. granosa and its closest related species was estimated to be 460 thousand years ago. This study provides a phylogenetic framework for this ecologically prominent and commercially important cockle species. PMID:21732288

  17. Vibrio parahaemolyticus and its specific bacteriophages as an indicator in cockles (Anadara granosa) for the risk of V. parahaemolyticus infection in Southern Thailand.

    PubMed

    Yingkajorn, Mingkwan; Sermwitayawong, Natthawan; Palittapongarnpimp, Prasit; Nishibuchi, Mitsuaki; Robins, William P; Mekalanos, John J; Vuddhakul, Varaporn

    2014-05-01

    Correlation between the numbers of Vibrio parahaemolyticus and its specific bacteriophages in cockles was investigated from June 2009 to May 2010 in Hat Yai, Songkhla, Thailand. Cockles obtained monthly from a local market were sampled to determine the numbers of V. parahaemolyticus and bacteriophages that could form plaques on ten strains of pandemic and nonpandemic V. parahaemolyticus. In addition, V. parahaemolyticus isolates from clinical samples from Hat Yai hospital over the same period were investigated. All 139 cockles sampled were positive for V. parahaemolyticus. However, only 76 of them were positive for bacteriophages. During the testing period, the number of bacteriophages was not significantly correlated with the incidence of V. parahaemolyticus-infected patients, but the numbers of V. parahaemolyticus isolates from the cockle samples were closely related to the number of infected patients. The bacteriophages isolated from V. parahaemolyticus also infected Vibrio alginolyticus and Vibrio mimicus, suggesting that the broad host range of phages may be a factor of providing the possibility of their participation in the processes of genetic exchange between V. parahaemolyticus and closely related Vibrio spp. In conclusion, this study indicated that the number of V. parahaemolyticus in cockles may be a useful tool for predicting the relative risk of infection by V. parahaemolyticus in this area of Thailand. PMID:24682339

  18. Strontium/lithium ratios in shells of Cerastoderma edule - A potential temperature proxy for brackish environments

    NASA Astrophysics Data System (ADS)

    Füllenbach, Christoph S.; Schöne, Bernd R.; Mertz-Kraus, Regina

    2015-04-01

    Bivalve shells provide high-resolution records of climate variability. However, the number of suitable proxies to quantify environmental variables is still limited. The most frequently used and well-accepted tool for environmental reconstructions from shell carbonate, δ18Oshell, is a dual proxy that simultaneously informs about water temperature and the oxygen isotope signature of the water. Reconstruction of water temperature requires knowledge of δ18Owater and reconstruction of the latter requires knowledge of salinity. Element-to-calcium ratios that are frequently used in other biological carbonates as tools for temperature reconstructions such as Sr/Cashell or Mg/Cashell are strongly biologically controlled in bivalves and show only a weak correlation to temperature. Here, we present Sr/Lishell ratios as a new temperature proxy that can complement δ18Oshell-based environmental reconstructions. In seawater, strontium and lithium have long residence times of 1.5Ma and 2Ma, respectively. Furthermore, salinity changes do not appear to affect the incorporation of Sr2+ and Li+ into the shells. Sr and Li concentrations were determined via LA-ICP-MS (line-scan method) in aragonitic shells of four Cerastoderma edule specimens collected alive from the intertidal zone of the North Sea. Geochemical data from the ontogenetic year three (growing season: April - September) were placed in precise temporal context by using tidal growth patterns and then compared to instrumental water temperature and water chemistry data. Sr/Lishell values (15 to 287 mmol/mmol) are significantly above Sr/Liwater (1.9 to 3.3 mmol/mmol) suggesting the presence of vital effects. However, all shells revealed similar Sr/Lishell patterns that are strongly negatively correlated to water temperature (r2 = 0.65 to 0.74; p < 0.01; T = -0.056 (±0.005) * (Sr/Lishell) [mmol/mmol] + 23.188 (±0.92)). To test the robustness of the presented proxy, we applied the new paleothermometry equation (Sr/Lishell vs

  19. Purification and Partial Characterization of β-Glucosidase in Chayote (Sechium edule).

    PubMed

    Mateos, Sergio Espíndola; Cervantes, Carlos Alberto Matías; Zenteno, Edgar; Slomianny, Marie-Christine; Alpuche, Juan; Hernández-Cruz, Pedro; Martínez-Cruz, Ruth; Canseco, Maria del Socorro Pina; Pérez-Campos, Eduardo; Rubio, Manuel Sánchez; Mayoral, Laura Pérez-Campos; Martínez-Cruz, Margarito

    2015-01-01

    β-Glucosidase (EC 3.2.1.21) is a prominent member of the GH1 family of glycoside hydrolases. The properties of this β-glucosidase appear to include resistance to temperature, urea, and iodoacetamide, and it is activated by 2-ME, similar to other members. β-Glucosidase from chayote (Sechium edule) was purified by ionic-interchange chromatography and molecular exclusion chromatography. Peptides detected by LC-ESI-MS/MS were compared with other β-glucosidases using the BLAST program. This enzyme is a 116 kDa protein composed of two sub-units of 58 kDa and shows homology with Cucumis sativus β-glucosidase (NCBI reference sequence XP_004154617.1), in which seven peptides were found with relative masses ranging from 874.3643 to 1587.8297. The stability of β-glucosidase depends on an initial concentration of 0.2 mg/mL of protein at pH 5.0 which decreases by 33% in a period of 30 h, and then stabilizes and is active for the next 5 days (pH 4.0 gives similar results). One hundred μg/mL β-D-glucose inhibited β-glucosidase activity by more than 50%. The enzyme had a Km of 4.88 mM with p-NPG and a Kcat of 10,000 min(-1). The optimal conditions for the enzyme require a pH of 4.0 and a temperature of 50 °C. PMID:26561793

  20. Purification and Partial Characterization of β-Glucosidase in Chayote (Sechium edule).

    PubMed

    Mateos, Sergio Espíndola; Cervantes, Carlos Alberto Matías; Zenteno, Edgar; Slomianny, Marie-Christine; Alpuche, Juan; Hernández-Cruz, Pedro; Martínez-Cruz, Ruth; Canseco, Maria Del Socorro Pina; Pérez-Campos, Eduardo; Rubio, Manuel Sánchez; Mayoral, Laura Pérez-Campos; Martínez-Cruz, Margarito

    2015-01-01

    β-Glucosidase (EC 3.2.1.21) is a prominent member of the GH1 family of glycoside hydrolases. The properties of this β-glucosidase appear to include resistance to temperature, urea, and iodoacetamide, and it is activated by 2-ME, similar to other members. β-Glucosidase from chayote (Sechium edule) was purified by ionic-interchange chromatography and molecular exclusion chromatography. Peptides detected by LC-ESI-MS/MS were compared with other β-glucosidases using the BLAST program. This enzyme is a 116 kDa protein composed of two sub-units of 58 kDa and shows homology with Cucumis sativus β-glucosidase (NCBI reference sequence XP_004154617.1), in which seven peptides were found with relative masses ranging from 874.3643 to 1587.8297. The stability of β-glucosidase depends on an initial concentration of 0.2 mg/mL of protein at pH 5.0 which decreases by 33% in a period of 30 h, and then stabilizes and is active for the next 5 days (pH 4.0 gives similar results). One hundred μg/mL β-D-glucose inhibited β-glucosidase activity by more than 50%. The enzyme had a Km of 4.88 mM with p-NPG and a Kcat of 10,000 min(-1). The optimal conditions for the enzyme require a pH of 4.0 and a temperature of 50 °C. PMID:26556317

  1. Purification and Partial Characterization of β-Glucosidase in Chayote (Sechium edule).

    PubMed

    Mateos, Sergio Espíndola; Cervantes, Carlos Alberto Matías; Zenteno, Edgar; Slomianny, Marie-Christine; Alpuche, Juan; Hernández-Cruz, Pedro; Martínez-Cruz, Ruth; del Socorro Pina Canseco, Maria; Pérez-Campos, Eduardo; Rubio, Manuel Sánchez; Mayoral, Laura Pérez-Campos; Martínez-Cruz, Margarito

    2015-01-01

    β-Glucosidase (EC 3.2.1.21) is a prominent member of the GH1 family of glycoside hydrolases. The properties of this β-glucosidase appear to include resistance to temperature, urea, and iodoacetamide, and it is activated by 2-ME, similar to other members. β-Glucosidase from chayote (Sechium edule) was purified by ionic-interchange chromatography and molecular exclusion chromatography. Peptides detected by LC-ESI-MS/MS were compared with other β-glucosidases using the BLAST program. This enzyme is a 116 kDa protein composed of two sub-units of 58 kDa and shows homology with Cucumis sativus β-glucosidase (NCBI reference sequence XP_004154617.1), in which seven peptides were found with relative masses ranging from 874.3643 to 1587.8297. The stability of β-glucosidase depends on an initial concentration of 0.2 mg/mL of protein at pH 5.0 which decreases by 33% in a period of 30 h, and then stabilizes and is active for the next 5 days (pH 4.0 gives similar results). One hundred μg/mL β-D-glucose inhibited β-glucosidase activity by more than 50%. The enzyme had a Km of 4.88 mM with p-NPG and a Kcat of 10,000 min(-1). The optimal conditions for the enzyme require a pH of 4.0 and a temperature of 50 °C. PMID:26512637

  2. DISINTEGRATION OF THE CELLS OF SIPHONOUS GREEN ALGA CODIUM EDULE (BRYOPSIDALES, CHLOROPHYTA) UNDER MILD HEAT STRESS(1).

    PubMed

    Lee, Tzan-Chain; Hsu, Ban-Dar

    2009-04-01

    The siphonous green alga Codium edule P. C. Silva (Bryopsidales, Chlorophyta) has the highest covering ratio among the macroalgae on the coral reef of Nanwan Bay in southern Taiwan, but its population in the subtidal region drastically decreases from July to September each year. The objective of this study was to determine whether the high temperature of summer could be the basis for this population decrease. Chlorophyll fluorescence measurements revealed that when the algae were incubated at 35°C (a temperature that can be reached in southern Taiwan during the summer), their photosynthetic activities were almost completely inhibited after about 8 h. The circadian rhythm of photosynthesis was disrupted at a temperature as low as 32°C. TEM studies showed that 4 h incubation at 35°C induced a decrease in turgidity accompanied by vacuole shrinkage and plasmolysis. The marked disintegrative changes, including damage to organelles, such as chloroplasts and nuclei, occurred after about 8 h, at which time central vacuoles collapsed and the cell interior was then filled with numerous small vesicles. Our results suggested that the rise in seawater temperature during the summer could be one of the major causes of the massive death of C. edule in the field. PMID:27033813

  3. Mercury depuration effectiveness on green mussel (Perna viridis L.) and blood cockle (Anadara granosa L.) from Jakarta Bay using ozone, chitosan and hydrodynamic technique

    NASA Astrophysics Data System (ADS)

    Widiah Ningrum, Endar; Duryadi Solihin, Dedy; Butet, Nurlisa A.

    2016-01-01

    Depuration has been used to eliminate microorganism and toxic chemical contaminants in bivalve. However, scientific research still needs to discover the effectiveness of depuration. This research aimed at assessing the best depuration effectiveness in decreasing mercury (Hg) concentration level in two species of bivalves, green mussel (Perna viridis L.) and blood cockle (Anadara granosa L.). The depuration treatments applied 1.5 ppm ozon, 0.5 ppm chitosan, hydrodynamic technique (1.3 m/s), combination between hydrodynamic-ozon, hydrodynamic-chitosan and ozon-chitosan. The experiment were conducted in mini aquaria for 60 minutes. Mercury concentration was measured in 10 g dry weight of green mussel (4.05±0.020 ppm) and blood cockle (3.27 ± 0.666 ppm). The result showed that mercury depuration were highly effective by combination of ozone-chitosan in green mussel (96.51%) and 1.5 ppm ozone in blood cockle (87.06%).

  4. Effect of a hemiuroid trematode on the hemocyte immune parameters of the cockle Anadara trapezia.

    PubMed

    Dang, Cécile; Cribb, Thomas H; Osborne, Geoffrey; Kawasaki, Minami; Bedin, Anne-Sophie; Barnes, Andrew C

    2013-09-01

    When a trematode parasite penetrates a potential molluscan host, it has to circumvent the host's internal defense system. In molluscs, the primary effector cells of this system are the hemocytes which orchestrate many of the cellular and humoral immune functions. Survival of the parasite can occur only in the absence of a successful immune response, and continued development only if the host is physiologically suitable. This study investigated hemocytic response against asexual stages of a hemiuroid trematode by its host, the marine bivalve Anadara trapezia. Hemocyte characteristic (type, morphology) and function (mortality, phagocytosis and oxidative activity) were analyzed by flow cytometry in parasitized and non-parasitized cockles. A. trapezia possesses two types of hemocytes: amebocytes and erythrocytes. Analysis of histological section showed that there was no host hemocytic response around hemiuroid sporocysts. The infection induced a significant increase of the total circulating hemocytes with a higher proportion of erythrocytes relative to amebocytes, coupled with a lower phagocytosis rate and a statistically non-significant decrease of the intracellular oxidative activity. No significant differences were observed in hemocyte size and complexity, mortality, or phagocytic capacity. Our results indicate that in A. trapezia, hemiuroids modulate the immune response by increasing the number of circulating hemocytes and decreasing phagocytosis. PMID:23867496

  5. Development and characterization of novel porous 3D alginate-cockle shell powder nanobiocomposite bone scaffold.

    PubMed

    Bharatham, B Hemabarathy; Abu Bakar, Md Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  6. Development and Characterization of Novel Porous 3D Alginate-Cockle Shell Powder Nanobiocomposite Bone Scaffold

    PubMed Central

    Bharatham, B. Hemabarathy; Abu Bakar, Md. Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  7. Molecular phylogenetics and historical biogeography amid shifting continents in the cockles and giant clams (Bivalvia: Cardiidae).

    PubMed

    Herrera, Nathanael D; Ter Poorten, Jan Johan; Bieler, Rüdiger; Mikkelsen, Paula M; Strong, Ellen E; Jablonski, David; Steppan, Scott J

    2015-12-01

    Reconstructing historical biogeography of the marine realm is complicated by indistinct barriers and, over deeper time scales, a dynamic landscape shaped by plate tectonics. Here we present the most extensive examination of model-based historical biogeography among marine invertebrates to date. We conducted the largest phylogenetic and molecular clock analyses to date for the bivalve family Cardiidae (cockles and giant clams) with three unlinked loci for 110 species representing 37 of the 50 genera. Ancestral ranges were reconstructed using the dispersal-extinction-cladogenesis (DEC) method with a time-stratified paleogeographic model wherein dispersal rates varied with shifting tectonics. Results were compared to previous classifications and the extensive paleontological record. Six of the eight prior subfamily groupings were found to be para- or polyphyletic. Cardiidae originated and subsequently diversified in the tropical Indo-Pacific starting in the Late Triassic. Eastern Atlantic species were mainly derived from the tropical Indo-Mediterranean region via the Tethys Sea. In contrast, the western Atlantic fauna was derived from Indo-Pacific clades. Our phylogenetic results demonstrated greater concordance with geography than did previous phylogenies based on morphology. Time-stratifying the DEC reconstruction improved the fit and was highly consistent with paleo-ocean currents and paleogeography. Lastly, combining molecular phylogenetics with a rich and well-documented fossil record allowed us to test the accuracy and precision of biogeographic range reconstructions. PMID:26234273

  8. Development of nanoantibiotic delivery system using cockle shell-derived aragonite nanoparticles for treatment of osteomyelitis

    PubMed Central

    Saidykhan, Lamin; Abu Bakar, Md Zuki Bin; Rukayadi, Yaya; Kura, Aminu Umar; Latifah, Saiful Yazan

    2016-01-01

    A local antibiotic delivery system (LADS) with biodegradable drug vehicles is recognized as the most effective therapeutic approach for the treatment of osteomyelitis. However, the design of a biodegradable LADS with high therapeutic efficacy is too costly and demanding. In this research, a low-cost, facile method was used to design vancomycin-loaded aragonite nanoparticles (VANPs) with the aim of understanding its potency in developing a nanoantibiotic bone implant for the treatment of osteomyelitis. The aragonite nanoparticles (ANPs) were synthesized from cockle shells by a hydrothermal approach using a zwitterionic surfactant. VANPs were prepared using antibiotic ratios of several nanoparticles, and the formulation (1:4) with the highest drug-loading efficiency (54.05%) was used for physicochemical, in vitro drug release, and biological evaluation. Physiochemical characterization of VANP was performed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction, and Zetasizer. No significant differences were observed between VANP and ANP in terms of size and morphology as both samples were cubic shaped with sizes of approximately 35 nm. The Fourier transform infrared spectroscopy of VANP indicated a weak noncovalent interaction between ANP and vancomycin, while the zeta potential values were slightly increased from −19.4±3.3 to −21.2±5.7 mV after vancomycin loading. VANP displayed 120 hours (5 days) release profile of vancomycin that exhibited high antibacterial effect against methicillin-resistant Staphylococcus aureus ATCC 29213. The cell proliferation assay showed 80% cell viability of human fetal osteoblast cell line 1.19 treated with the highest concentration of VANP (250 µg/mL), indicating good biocompatibility of VANP. In summary, VANP is a potential formulation for the development of an LADS against osteomyelitis with optimal antibacterial efficacy, good bone resorbability, and biocompatibility. PMID

  9. Development of nanoantibiotic delivery system using cockle shell-derived aragonite nanoparticles for treatment of osteomyelitis.

    PubMed

    Saidykhan, Lamin; Abu Bakar, Md Zuki Bin; Rukayadi, Yaya; Kura, Aminu Umar; Latifah, Saiful Yazan

    2016-01-01

    A local antibiotic delivery system (LADS) with biodegradable drug vehicles is recognized as the most effective therapeutic approach for the treatment of osteomyelitis. However, the design of a biodegradable LADS with high therapeutic efficacy is too costly and demanding. In this research, a low-cost, facile method was used to design vancomycin-loaded aragonite nanoparticles (VANPs) with the aim of understanding its potency in developing a nanoantibiotic bone implant for the treatment of osteomyelitis. The aragonite nanoparticles (ANPs) were synthesized from cockle shells by a hydrothermal approach using a zwitterionic surfactant. VANPs were prepared using antibiotic ratios of several nanoparticles, and the formulation (1:4) with the highest drug-loading efficiency (54.05%) was used for physicochemical, in vitro drug release, and biological evaluation. Physiochemical characterization of VANP was performed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction, and Zetasizer. No significant differences were observed between VANP and ANP in terms of size and morphology as both samples were cubic shaped with sizes of approximately 35 nm. The Fourier transform infrared spectroscopy of VANP indicated a weak noncovalent interaction between ANP and vancomycin, while the zeta potential values were slightly increased from -19.4±3.3 to -21.2±5.7 mV after vancomycin loading. VANP displayed 120 hours (5 days) release profile of vancomycin that exhibited high antibacterial effect against methicillin-resistant Staphylococcus aureus ATCC 29213. The cell proliferation assay showed 80% cell viability of human fetal osteoblast cell line 1.19 treated with the highest concentration of VANP (250 µg/mL), indicating good biocompatibility of VANP. In summary, VANP is a potential formulation for the development of an LADS against osteomyelitis with optimal antibacterial efficacy, good bone resorbability, and biocompatibility. PMID

  10. Human health risk of polycyclic aromatic hydrocarbons from consumption of blood cockle and exposure to contaminated sediments and water along the Klang Strait, Malaysia.

    PubMed

    Tavakoly Sany, Seyedeh Belin; Hashim, Rosli; Rezayi, Majid; Salleh, Aishah; Rahman, Mohammad Azizur; Safari, Omid; Sasekumar, A

    2014-07-15

    The concentration of carcinogenic poly aromatic hydrocarbons (c-PAHs) present in water and sediment of Klang Strait as well as in the edible tissue of blood cockle (Anadara granosa) was investigated. The human health risk of c-PAHs was assessed in accordance with the standards of the United States Environmental Protection Agency (US EPA). The cancer risks of c-PAHs to human are expected to occur through the consumption of blood cockles or via gastrointestinal exposure to polluted sediments and water in Kalng Strait. The non-carcinogenic risks that are associated with multiple pathways based on ingestion rate and contact rates with water were higher than the US EPA safe level at almost all stations, but the non-carcinogenic risks for eating blood cockle was below the level of US EPA concern. A high correlation between concentrations of c-PAHs in different matrices showed that the bioaccumulation of c-PAHs by blood cockles could be regarded as a potential health hazard for the consumers. PMID:24855978

  11. Transcriptional response of stress-regulated genes to cadmium exposure in the cockle Cerastoderma glaucum from the gulf of Gabès area (Tunisia).

    PubMed

    Karray, Sahar; Marchand, Justine; Moreau, Brigitte; Tastard, Emmanuelle; Thiriet-Rupert, Stanislas; Geffard, Alain; Delahaut, Laurence; Denis, Françoise; Hamza-Chaffai, Amel; Chénais, Benoît

    2015-11-01

    This study investigates cadmium effects on key messenger RNA (mRNA) expression (MT, MnSOD, CuZnSOD, CAT, ABCB1, HSP70, and CO1) by qPCR in the cockle Cerastoderma glaucum after chronic exposure to two high but environmentally relevant concentrations of CdCl2 (50 μg/L and 5 mg/L) for 12 h to 18 days. Cd accumulation measured in cockles' tissues is significantly higher in both treatment conditions compared to controls and in a dose-dependent manner. Stress on stress tests performed at different times of the experiment clearly demonstrated that exposure to both concentrations of Cd significantly affects cockle survival time in air. Important changes in gene transcription were also highlighted. In particular, MT, HSP70, CAT, and CuZnSOD seem to be relevant biomarkers of Cd exposure because (1) their mRNA levels increase upon exposure and (2) they are highly correlated to Cd accumulation in tissues. Results may be useful for control strategies and for the use of cockles as sentinel organisms. PMID:25523290

  12. Preliminary investigations on a new method of retaining the colour of shucked cockles ( Anadara Granosa), and the extension of shelflife by gamma irradiation and vacuum packing

    NASA Astrophysics Data System (ADS)

    Ng, Cher Siang; Low, Lai Kim; Chia, Lawrence H. L.

    Live cockles were incubated in atmospheres containing different concentrations of carbon monoxide. Since CO combines more readily with myoglobin and haemoglobin than oxygen, the formation of in vivo deoxygenated haemoglobins and post mortem formation of methaemoglobin were retarded by the more stable carboxyhaemoglobin (HbCO). The bright red colour of the stable HbCO is retained during storage, giving the desired colour to the cockles. The colour of normal, chilled cockle meat deteriorated after 3 days ice storage while those treated with 50 and 100% CO retained the bright deep orange colour up to 10 days storage. Irradiation caused faster colour deterioration in both CO and non-CO treated samples. Vacuum packing influenced the colour of the cockles with irradiation and with CO treatments. In non-CO treated, irradiated samples, the effect of vacuum packing was not obvious. In CO treated, irradiated samples, vacuum packing retarded the deterioration of colour. Odour developments were influenced by irradiation, vacuum packing and storage temperature, and were not influenced by CO treatments. Irradiation suppressed the development of odour for the first 11 days storage (0°C) while vacuum packing depressed the odour by lowering its intensity instead. Odour development was slowed down by lowering the storage temperature. The odour of shucked cockles was rejected within one day at room temperature (26-28°C) while at 0°C the odour of the shucked cockles was still acceptable after 10 days. Suitable chemical indices for quality are K value and TVBN. Treatment with CO did not influence the K value development. Vacuum packing produced the highest K values after 19 days storage (0°C), while irradiated samples had higher K values than non-irradiated samples. The TVBN increased with storage and is an indicator of the odour development. The use of CO treatment extended the shelflife of the cockles based on appearance. A combination of CO treatment, vacuum packing, ice storage

  13. Can shell scars on dog cockles ( Glycymeris glycymeris L.) be used as an indicator of fishing disturbance?

    NASA Astrophysics Data System (ADS)

    Ramsay, K.; Kaiser, M. J.; Richardson, C. A.; Veale, L. O.; Brand, A. R.

    2000-05-01

    The use of shell damage records as an in situ indicator of past fishing disturbance was investigated using the dog cockle Glycymeris glycymeris L. Shell sections of dog cockles collected from four areas subjected to varying levels of fishing disturbance were examined for the presence of damage records or shell 'scars'. Animals from a heavily fished area had significantly higher levels of scarring than those from three lightly fished areas. From an estimation of the age of the shells (from internal growth lines and dating of each line), the year in which scarring occurred was determined and this was compared to yearly records of fishing effort. There was a weak but significant positive correlation between the frequency of shell scars per year and the intensity of fishing effort. Our data suggest that whilst scarring in shells of G. glycymeris cannot accurately be used to estimate past fishing intensity on a year-by-year basis, it can be used to differentiate between severely impacted and lightly fished areas of the sea bed.

  14. Bizionia fulviae sp. nov., isolated from the gut of an egg cockle, Fulvia mutica.

    PubMed

    Kim, Hyun Sik; Hyun, Dong-Wook; Kim, Pil Soo; Lee, June-Young; Shin, Na-Ri; Yun, Ji-Hyun; Whon, Tae Woong; Kim, Min-Soo; Jung, Mi-Ja; Bae, Jin-Woo

    2015-09-01

    A novel Gram-staining-negative, non-spore-forming, non-flagellated, non-motile, aerobic, saffron-coloured, rod-shaped bacterium that did not produce flexirubin-type pigments was designated strain EM7(T) and was distinct from other members of the genus Bizionia by produce carotenoid-type pigments and being able to grow independently of NaCl. Strain EM7(T) was isolated from the intestinal tract of an egg cockle, Fulvia mutica, which had been collected from the West Sea in Korea. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain EM7(T) belonged to the genus Bizionia, and showed sequence similarity to Bizionia paragorgiae KMM 6029(T) (97.9%) and Bizionia saleffrena HFD(T) (97.73%). Growth occurred on marine agar 2216 at 0-25 °C (optimum, 20 °C) and at pH 6-9 (optimum, pH 7). Growth occurred in the presence of 0-10% (w/v) NaCl (optimum, 2%, w/v, NaCl). The major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, iso-C15 : 1 G, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH and iso-C16 : 0 3-OH. The major respiratory quinone was menaquinone MK-6. The polar lipids of strain EM7(T) comprised phosphatidylethanolamine, three unidentified aminolipids, an unidentified aminophospholipid and two unidentified lipids. The genomic DNA G+C content was 34.8 mol%. Bizionia paragorgiae KMM 6029(T) and Bizionia saleffrena HFD(T) to Bizionia paragorgiae KCTC 12304(T) and Bizionia saleffrena CIP 108534(T), respectively. Thus, it is proposed that the isolate represents a novel species, Bizionia fulviae sp. nov., with strain EM7(T) ( = KACC 18255(T) = JCM 30417(T)) as the type strain. PMID:26297143

  15. Effect of feeding chayote (Sechium edule) meal on growth performance and nutrient utilization in indigenous pig (Zovawk) of Mizoram

    PubMed Central

    Lalthansanga, James; Samanta, A. K.

    2015-01-01

    Aim: This study was planned to investigate the effect of feeding different levels of chayote (Sechium edule) meal by replacing standard concentrate mixture (CM) on the growth parameters such as feed intake, body weight gain, average daily gain (ADG) and feed conversion ratio (FCR), and nutrient utilization in indigenous pig of Mizoram. Materials and Methods: Twenty-four growing indigenous pigs (Zovawk) were used to study the effect of feeding chayote (Sechium edule) meal (fruits and leaves at the ratio 4:1) on growth performance and nutrient utilization. They were allocated randomly into 4 treatment groups (G1, G2, G3, and G4). Chayote meal was used to replace standard CM (pig grower ration) at 0% (G1), 20% (G2), 30% (G3), and 40% (G4). Results: During the feeding trial of 90 days, it was found that the dry matter (DM) intake decreased as the level of chayote meal increased. For G1, G2, G3, and G4, the ADG (kg) was 0.24±0.04, 0.23±0.03, 0.18±0.02, and 0.18±0.02, respectively, and the feed conversion efficiency was 5.42±0.44, 4.93±0.17, 5.38±0.05, and 5.74±0.53, respectively. However, there was no significant difference (p>0.05) among the different treatment groups in respect to ADG and FCR. At the end of the feeding trial, digestibility trial was conducted to study the effect of feeding chayote meal in the digestibility of the different nutrients by the experimental animals. From the digestibility trial, it was revealed that the digestibility coefficient of DM, crude protein, and crude fiber were also similar (p>0.05), although the ether extract digestibility in G1 was significantly low (p<0.01) as compared to G2, G3, and G4. Conclusion: Chayote meal could safely replace the standard grower ration up to 40% in the diet of growing local pigs without causing any adverse effects on growth and nutrient utilization. PMID:27047176

  16. Determination and reoxidation of the disulfide bridges of a squash-type trypsin inhibitor from Sechium edule seeds.

    PubMed

    Faça, Vitor M; Pereira, Sandra R; Laure, Hélen J; Greene, Lewis J

    2004-07-01

    The determination of the disulfide pairings of SETI-II, a trypsin inhibitor isolated from Sechium edule, is described herein. The inhibitor contains 31 amino acid residues per mol, 6 of which are cysteine. Forty-five nmol (160 microg) of SETI-II was hydrolyzed with 20 microg thermolysin for 48 hr at 45 degrees C, and peptides were separated by reverse phase high performance liquid chromatography (RP-HPLC). The major products were identified by amino acid composition, Edman degradation, and on the basis of the sequence of the inhibitor. The disulfide bridge pairings and (yields) are: Cys1-Cys4 (79%), Cys2-Cys5 (21%) and Cys3-Cys6 (43%). When the reduced inhibitor was reoxidized with glutathione reduced form (GSH)/glutathione oxidized form (GSSG) at pH 8.5 for 3 hr, full activity was recovered. These data show that disulfide bridge pairing and oxidation can be determined at nanomole levels and that sensitive and quantitative Edman degradation can eliminate the final time- and material-consuming step of disulfide determinations by eliminating the need to purify and cleave each peptide containing a disulfide bridge. PMID:15328886

  17. Statistical analysis of heavy metals in Cerastoderma edule glaucum and Venerupis aurea laeta from Ganzirri Lake, Messina (Italy).

    PubMed

    Di Bella, Giuseppa; Turco, Vincenzo Lo; Potortì, Angela Giorgia; Rando, Rossana; Licata, Patrizia; Dugo, Giacomo

    2013-09-01

    Our study was carried out on two species of clams, Venerupis aurea laeta and Cerastoderma edule glaucum, from Ganzirri Lake considered as "environmental biomarkers" for their changes in physiology, morphology or distribution under the influence of substances in the environment. The aim of the present study was to conduct a statistical analysis on Venerupis and Cerastoderma to investigate the difference between the two autochthonous clams according to the presence of metals, and to link metal concentrations to the reproductive cycle of clam during 2009-2010. Metal analysis was carried out with inductively coupled plasma mass spectrometry (ICP-MS). Accuracy and precision were assessed by analyzing the certified standard matrix: mussel tissue NIST SRM 2976. The multivariate analysis was made using the SPSS 13.0 software package for Windows (SPSS Inc., Chicago, IL). In this study, the concentrations of some metals found in clam tissues showed seasonal cycles with higher values in summer than in winter. The significances of metal concentrations differences between Venerupis and Cerastoderma samples were estimated with Mann-Whitney U-test. The concentrations of Ag, As, Cd, Mn, Se and Zn show a significant p-level that suggests a difference between the two group samples. Statistical analysis showed that the link of metal concentrations to the reproductive cycles of Venerupis and Cerastoderma was not evident. PMID:23412955

  18. The potential of ocean acidification on suppressing larval development in the Pacific oyster Crassostrea gigas and blood cockle Arca inflata Reeve

    NASA Astrophysics Data System (ADS)

    Li, Jiaqi; Jiang, Zengjie; Zhang, Jihong; Mao, Yuze; Bian, Dapeng; Fang, Jianguang

    2014-11-01

    We evaluated the effect of pH on larval development in larval Pacific oyster ( Crassostrea gigas) and blood cockle ( Arca inflata Reeve). The larvae were reared at pH 8.2 (control), 7.9, 7.6, or 7.3 beginning 30 min or 24 h post fertilization. Exposure to lower pH during early embryonic development inhibited larval shell formation in both species. Compared with the control, larvae took longer to reach the D-veliger stage when reared under pH 7.6 and 7.3. Exposure to lower pH immediately after fertilization resulted in significantly delayed shell formation in the Pacific oyster larvae at pH 7.3 and blood cockle larvae at pH 7.6 and 7.3. However, when exposure was delayed until 24 h post fertilization, shell formation was only inhibited in blood cockle larvae reared at pH 7.3. Thus, the early embryonic stages were more sensitive to acidified conditions. Our results suggest that ocean acidification will have an adverse effect on embryonic development in bivalves. Although the effects appear subtle, they may accumulate and lead to subsequent issues during later larval development.

  19. Effects of deep frying on proximate composition and micronutrient of Indian mackerel (Rastrelliger kanagurta), eel (Monopterus albus) and cockle (Anadara granosa).

    PubMed

    Rahman, M M; Zamri, M; Fadilla, N

    2012-06-15

    This study was conducted to determine the proximate composition and four micronutrients (Cd, Cu, Mn and Zn) of Indian Mackerel (Rastrelliger kanagurta), Eel (Monopterus albus) and Cockle (Anadara granosa). All fish and shellfish were purchased from local fish market in Kuantan city. All samples of each species were mixed and divided into two groups based on random selection. Each group were again divided into 3 sub-groups which were considered as replications. The first group were kept uncooked. The second group were fried in a beaker of 400 mL palm cooking oil capacity at a temperature approximately of 180 degrees C for a 15 min period. Both raw and fried samples were analysed following standard methods to determine protein, lipid, ash, moisture, carbohydrate, Cd, Cu, Mn and Zn contents. Results showed that protein content was higher in Indian mackerel and eel than cockle while overall Cd, Cu, Mn and Zn contents were higher in cockle than Indian mackerel and eel. Therefore, fish is better than shellfish in the nutritional point of view. Fried fish and shellfish had very high fat content. Therefore, frying cannot be recommended to prepare a healthy diet. More research is needed including all cooking methods of fish to know the nutritional changes by each cooking method. Fish contains many important fatty acids and amino acids which might be lost during frying. Therefore, future study should include the effects of different cooking methods on amino acids and fatty acids compositions of fish and shellfish. PMID:24191621

  20. Concentration of Mercury in Cockles (Anadara granosa and A. antiquata) Harvested from Estuaries of Western Lombok, Indonesia, and Potential Risks to Human Health.

    PubMed

    Rahayu, Rachmawati Noviana; Irawan, Bambang; Soegianto, Agoes

    2016-01-01

    This study measured the levels of total mercury (tHg) in the whole tissues of cockles (Anadara granosa and A. antiquata) harvested from three estuaries of Western Lombok Island (WLI), Indonesia. This paper also evaluated the hazard level posed by the mercury in relation to the maximum residual limit for human consumption and to estimate the weekly intake and compare it with the provisional tolerable weekly intake (PTWI). The tHg concentrations in A. granosa ranged from 0.020 to 0.070 mg kg(-1), and those in A. antiquata were between 0.032 and 0.077 mg kg(-1) at all locations. All samples of cockles harvested from WLI contain tHg below the permissible limit for human consumption. The maximum weekly intakes for total mercury by coastal people range from 0.28 to 1.08 µg kg(-1) b.w., and they are below the recommended values of PTWI (5.6 µg kg(-1) b.w.). If it is assumed that 100% of the Hg in cockles is methyl mercury (MeHg), consumption of the indicated amounts at the measured values wouldn't exceed the MeHg PTWI (1.6 µg kg(-1) b.w.). PMID:26450597

  1. A review of science-policy interactions in the Dutch Wadden Sea - The cockle fishery and gas exploitation controversies

    NASA Astrophysics Data System (ADS)

    Floor, Judith R.; van Koppen, C. S. A. (Kris); Lindeboom, Han J.

    2013-09-01

    The potential ecological effects of cockle fisheries and gas exploitation in the Dutch Wadden Sea and their implications for policy and management have been the topic of vigorous societal debates. Ecological science has played crucial but controversial roles in these debates. Several social science studies have been dedicated to analysing these roles and making recommendations for the improvement of science-policy interactions. In reviewing these studies, this article aims to draw lessons for (ecological) scientists and policy makers on how to understand and guide the interactions of science and policy in Wadden Sea management. Studies addressing science-policy interactions in the Dutch Wadden Sea can be grouped into three main perspectives, emphasizing the social and economic dynamics of resource management, the role of nature views and discourses in controversies, and the influence of science dynamics in policy and management debates. The review demonstrates that ecological knowledge and ecological scientists have played important roles in the controversies on cockle fisheries and gas exploitation. However, scientific knowledge was not always the most important factor in the decision-making process, and scientific insights were not always used as expected by the scientists. How scientific knowledge is used and interpreted by stakeholders was dependent on their interests, their nature views and on the dominant policy discourses. Ecological knowledge and scientists themselves became part of the policy debates, e.g. in discussions on uncertainty and reliability. The position of scientists in policy debates was strongly influenced by the policy setting and by changes in this setting, e.g. by the operation of mediators or by new interpretations of legal rules. A lesson to be drawn for scientists is that they should reflect on the sort of position - e.g. independent outsider, or engaged stakeholder - they take in a debate. They should also be aware that this position

  2. Sechium edule Shoot Extracts and Active Components Improve Obesity and a Fatty Liver That Involved Reducing Hepatic Lipogenesis and Adipogenesis in High-Fat-Diet-Fed Rats.

    PubMed

    Yang, Mon-Yuan; Chan, Kuei-Chuan; Lee, Yi-Ju; Chang, Xiao-Zong; Wu, Cheng-Hsun; Wang, Chau-Jong

    2015-05-13

    Excess fat accumulation in the liver increases the risk of developing progressive liver injuries ranging from a fatty liver to hepatocarcinoma. In a previous study, we demonstrated that the polyphenol components of Sechium edule shoots attenuated hepatic lipid accumulation in vitro. Therefore, we investigated the effects and mechanisms of the extract of S. edule shoots (SWE) to modulate fat accumulation in a high-fat-diet (HFD)-induced animal model. In this study, we found that the SWE can reduce the body weight, adipose tissue fat, and regulate hepatic lipid contents (e.g., triglyceride and cholesterol). Additionally, treatment of caffeic acid (CA) and hesperetin (HPT), the main ingredients of SWE, also inhibited oleic acid (OA)-induced lipid accumulation in HepG2 cells. SWE enhanced the activation of AMP-activating protein kinase (AMPK) and decreased numerous lipogenic-related enzymes, such as sterol regulator element-binding proteins (SREBPs), e.g., SREBP-1 and SREBP-2, and HMG-CoA reductase (HMGCoR) proteins, which are critical regulators of hepatic lipid metabolism. Taken together, the results demonstrated that SWE can prevent a fatty liver and attenuate adipose tissue fat by inhibiting lipogenic enzymes and stimulating lipolysis via upregulating AMPK. It was also demonstrated that the main activation components of SWE are both CA and HPT. PMID:25912298

  3. Single-laboratory validation of a refined AOAC HPLC method 2005.06 for oysters, cockles, and clams in U.K. shellfish.

    PubMed

    Turner, Andrew D; Hatfield, Robert G; Rapkova-Dhanji, Monika; Norton, Deirdre M; Algoet, Myriam; Lees, David N

    2010-01-01

    In 2009, a refined HPLC method based on AOAC Official Method 2005.06 was developed and validated for the determination of paralytic shellfish poisoning (PSP) in mussels. A single-laboratory validation study of this method was undertaken here for the analysis of PSP toxins in oysters, cockles, clams, and razor clams. The method was characterized for selectivity, sensitivity, linearity, precision, repeatability, recovery, ruggedness, and uncertainty of measurement. Validation data were utilized to determine method performance characteristics for non-mussel bivalves for all commercially available certified reference toxins, extending the method to dcNEO and dcGTX2,3, where available. A period of parallel testing of oysters, cockles, and clams enabled a comparison of sample toxicities obtained using mouse bioassay (MBA) and HPLC methodologies, although only a very low number of PSP-positive samples were obtained through the United Kingdom official control monitoring program. Results from the MBA and HPLC methods were well-correlated for PSP-negative samples, but the low number of naturally contaminated PSP-positive samples has prevented any comparative statistical assessment of method performance for non-mussels between the two official methods. However, some evidence for potentially significant differences in total saxitoxin equivalents obtained by the two methods in some species has highlighted the need for further comparative testing in non-mussel samples to be conducted prior to implementation of the HPLC method in routine official control monitoring programs. PMID:21140661

  4. Risk assessment for the daily intake of polycyclic aromatic hydrocarbons from the ingestion of cockle (Anadara granosa) and exposure to contaminated water and sediments along the west coast of Peninsular Malaysia.

    PubMed

    Mirsadeghi, Seiedeh Aghileh; Zakari, Mohamad Pauzi; Yap, Chee Kong; Shahbazi, Azadeh

    2011-01-01

    The concentration of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) present in the sediment and water of Peninsular Malaysia as well as in the cockle Anadara granosa was investigated. Samples were extracted and analysed with gas chromatography-mass spectrometry. The concentrations of total carcinogenic polycyclic aromatic hydrocarbons (t-PAHs) were measured between 0.80 +/- 0.04 to 162.96 +/- 14.74 ng/g wet weight (ww) in sediment, between 21.85 +/- 2.18 to 76.2 +/- 10.82 ng/L in water samples and between 3.34 +/- 0.77 to 46.85 +/- 5.50 ng/g ww in the cockle tissue. The risk assessment of probable human carcinogens in the Group B2 PAHs was calculated and assessed in accordance with the standards of the United States Environmental Protection Agency (US EPA). Case I in the toxicity assessment analysed the cancer risk to consumers of Malaysian blood cockle. Case II assessed the risk of cancer from exposure to PAHs from multiple pathways. The average cancer risk of case I and case II were found to be classifiable as unsafe according to the US EPA standard. The cancer risk due to c-PAHs acquired by the ingestion of blood cockle was (8.82 +/- 0.54) x 10-6 to (2.67 +/- 0.06) x 10(-2), higher than the US EPA risk management criterion. The non-cancer risks associated with multiple pathways in Kuala Gula, Kuala Juru and Kuala Perlis were higher than the U.S. EPA safe level, but the non-cancer risk for eating blood cockle was below the level of U.S. EPA concern. PMID:21517010

  5. Antioxidant and α-glucosidase inhibitory activities of cucurbit fruit vegetables and identification of active and major constituents from phenolic-rich extracts of Lagenaria siceraria and Sechium edule.

    PubMed

    Sulaiman, Shaida Fariza; Ooi, Kheng Leong; Supriatno

    2013-10-23

    Antioxidant and α-glucosidase activities and total phenolic contents (TPC) in sequential extracts of dried pulps from seven cucurbit fruit vegetables were determined for the first time. The highest TPC and metal chelating activity were obtained from the chloroform extracts of Luffa acutangula (28.04 ± 0.37 mg GAE/g extract) and Benincasa hispida (EC50 = 0.44 ± 0.03 mg/mL), respectively. The ethyl acetate extract of Sechium edule showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (951.73 ± 29.14 mM TE/g extract). The highest reducing and anti-α-glucosidase activities were shown by the methanol and ethyl acetate extracts of Momordica charantia (692.56 ± 43.38 mM AscAE/g extract; 66.64 ± 2.94%, respectively). The highest correlation (r = 0.99) was observed between the TPC and DPPH values of S. edule. Although caffeic acid was quantified as the major constituent in the methanol extract of Lagenaria siceraria , isoquercetin was found to be the main contributor to the activities. Gallic acid was identified as both the main and most active antioxidant constituent in the ethyl acetate extract of S. edule. PMID:24059845

  6. Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1.

    PubMed

    Isa, Tijani; Zakaria, Zuki Abu Bakar; Rukayadi, Yaya; Mohd Hezmee, Mohd Noor; Jaji, Alhaji Zubair; Imam, Mustapha Umar; Hammadi, Nahidah Ibrahim; Mahmood, Saffanah Khuder

    2016-01-01

    The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin-cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2'-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin-nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections. PMID:27213349

  7. Reproductive cycle and seasonal variations in lipid content and fatty acid composition in gonad of the cockle Fulvia mutica in relation to temperature and food

    NASA Astrophysics Data System (ADS)

    Liu, Wenguang; Li, Qi; Kong, Lingfeng

    2013-09-01

    From March 2004 to February 2005, seasonal variations in lipid content and fatty acid composition of gonad of the cockle Fulvia mutica (Reeve) were studied on the eastern coast of China in relation to the reproductive cycle and environment conditions ( e.g., temperature and food availability). Histological analysis as well as lipid and fatty acid analyses were performed on neutral and polar lipids of the gonad. Results showed that gametogenesis occurred in winter and spring at the expense of lipids previously accumulated in summer and autumn, whereas spawning occurred in summer (20.4-24.6°C). The seasonal variation in lipid content was similar to that of the mean oocyte diameter. In both neutral and polar lipids, the 20:5n-3 and 22:6n-3 levels were relatively higher than saturated fatty acids, and polyunsaturated fatty acids were abundant, with series n-3 as the predominant component. Seasonal variations in the 20:5n-3 and 22:6n-3 levels and the principal n-3 fatty acids were clearly related to the reproductive cycle. The Σ(n-3) and Σ(n-6) values were relatively high during January-May, and the associated unsaturation index was significantly higher than that in other months. The results suggest that fatty acids play an important role in the gametogenesis of F. mutica.

  8. Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1

    PubMed Central

    Isa, Tijani; Zakaria, Zuki Abu Bakar; Rukayadi, Yaya; Mohd Hezmee, Mohd Noor; Jaji, Alhaji Zubair; Imam, Mustapha Umar; Hammadi, Nahidah Ibrahim; Mahmood, Saffanah Khuder

    2016-01-01

    The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin–cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2′-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin–nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections. PMID:27213349

  9. Antibiotic resistance and molecular typing among cockle (Anadara granosa) strains of Vibrio parahaemolyticus by polymerase chain reaction (PCR)-based analysis.

    PubMed

    Sahilah, A M; Laila, R A S; Sallehuddin, H Mohd; Osman, H; Aminah, A; Ahmad Azuhairi, A

    2014-02-01

    Genomic DNA of Vibrio parahaemolyticus were characterized by antibiotic resistance, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis. These isolates originated from 3 distantly locations of Selangor, Negeri Sembilan and Melaka (East coastal areas), Malaysia. A total of 44 (n = 44) of tentatively V. parahaemolyticus were also examined for the presence of toxR, tdh and trh gene. Of 44 isolates, 37 were positive towards toxR gene; while, none were positive to tdh and trh gene. Antibiotic resistance analysis showed the V. parahaemolyticus isolates were highly resistant to bacitracin (92%, 34/37) and penicillin (89%, 33/37) followed by resistance towards ampicillin (68%, 25/37), cefuroxime (38%, 14/37), amikacin (6%, 2/37) and ceftazidime (14%, 5/37). None of the V. parahaemolyticus isolates were resistant towards chloramphenicol, ciprofloxacin, ceftriaxone, enrofloxacin, norfloxacin, streptomycin and vancomycin. Antibiogram patterns exhibited, 9 patterns and phenotypically less heterogenous when compared to PCR-based techniques using ERIC- and RAPD-PCR. The results of the ERIC- and RAPD-PCR were analyzed using GelCompare software. ERIC-PCR with primers ERIC1R and ERIC2 discriminated the V. parahaemolyticus isolates into 6 clusters and 21 single isolates at a similarity level of 80%. While, RAPD-PCR with primer Gen8 discriminated the V. parahaemolyticus isolates into 11 clusters and 10 single isolates and Gen9 into 8 clusters and 16 single isolates at the same similarity level examined. Results in the presence study demonstrated combination of phenotypically and genotypically methods show a wide heterogeneity among cockle isolates of V. parahaemolyticus. PMID:24068534

  10. The reproductive cycle, condition index, and glycogen reserves of the cockles Cerastoderma glaucum from the Gulf of Gabès (Tunisia).

    PubMed

    Karray, Sahar; Smaoui-Damak, Wafa; Rebai, Tarek; Hamza-Chaffai, Amel

    2015-11-01

    The gametogenic cycle of the Cerastoderma glaucum was analyzed using both qualitative and semi-quantitative methods. The condition index and glycogen concentrations were determined in order to provide information on energy storage. The cockles were collected monthly from a Bayyadha site located 15 km south of Sfax City (Gulf of Gabès) between January 2007 and January 2008. From histological point of view, we applied two approaches: (i) the qualitative method describing the various stages of gamete development for males and females during a cycle of 13 months, and (ii) the semi-quantitative method concerning the estimation of different tissue surfaces. The results showed that there is evidence of three periods of reproduction in this population. A comparison between the surfaces occupied by the three organs showed that the foot and the gonad surfaces are higher than the surface of the adductor muscle. This could suggest that these two organs are more involved in the process of glycogen reserve storage. The results of the glycogen concentrations in the different tissues (gonad, adductor muscle, and "remainders") show that during the second and third periods of reproduction, glycogen was stored in the adductor muscle and in the remainder during sexual rest, and in the gonad during the gametogenesis phases in order to supply the reproductive effort. On the contrary, in the first period of reproduction, the low concentrations of glycogen recorded in the gonad coincided with its high degree of development. This fact could be related to environmental conditions (low temperature and food) recorded during this period. PMID:25804659

  11. Tracing Environmental Variation Over The Past 130 Years In The Barents Sea: Mineral Ratio (Mg/Ca, Sr/Ca, Ba/Ca, And Mn/Ca) Evidence In Shells Of The Circumpolar Greenland Cockle, Serripes groenlandicus

    NASA Astrophysics Data System (ADS)

    Henkes, G. A.; Ambrose, W. G.; Johnson, B. J.; Carroll, M. L.; McMahon, K. W.; Denisenko, S. G.; Thorrold, S. R.

    2007-12-01

    In order to quantify the impacts of human induced climate change on Arctic marine ecosystems it is crucial to establish high-resolution proxies to record regional environmental variability. The Barents Sea region is highly influenced by the annual recession and precession of Arctic sea ice and, as an ecosystem is extremely sensitive to seasonal to decadal climatic changes. Long-lived, sessile, marine bivalves have the potential to provide detailed oceanographic and biological proxy information from the Barents Sea in locations where historic, long- term data logging does not exist. Here, we present preliminary mineral ratio evidence (Mg, Sr, Ba, Mn) for Barents Sea environmental variation from shells of the circumpolar Greenland cockle, Serripes groenlandicus, over the past 130 years from 4 different locations in Norwegian and Russian waters. For all mineral ratios there are clear seasonal trends corresponding with dark winter growth checks on the external surface of each individual. The seasonal patterns of Mg and Sr show progressive change. On average for 9 individuals, Mg/Ca was 10.6 percent greater and Sr/Ca was 5.5 percent lower on the winter checks compared to other values, while Ba/Ca and Mn/Ca ratios show peaks during the middle of the summer growth period. Mineral patterns from the Pechora Sea region are particularly pronounced, which may be related to the influence freshwater from summer river discharge. While the mineral data are initially compelling enough to demonstrate clear seasonal periodicity and inter-annual variation, we believe that a multi-proxy approach to interpreting the information obtained from these bivalves is critical. Therefore, parallel to this study, we are examining external, incremental growth and organic carbon isotopes of shell material from the same collection of bivalves.

  12. Comparative phylogeography of two sister (congeneric) species of cardiid bivalve: Strong influence of habitat, life history and post-glacial history

    NASA Astrophysics Data System (ADS)

    Tarnowska, Katarzyna; Krakau, Manuela; Jacobsen, Sabine; Wołowicz, Maciej; Féral, Jean-Pierre; Chenuil, Anne

    2012-07-01

    Sister (congeneric) species may exhibit disparate patterns of biogeographic genetic structures due to different life histories and habitat preferences. The common cockle Cerastoderma edule and the lagoon cockle Cerastoderma glaucum probably diverged from their common ancestor in the present territory of Sahara around 5 million years ago. Although it is difficult to separate both species morphologically, various genetic markers, both mitochondrial and nuclear, clearly distinguish them. Furthermore, their lifestyles are different, as C. edule has a much less fragmented coastal habitat and a longer duration of pelagic larval stage than C. glaucum. A comparative genetic analysis was conducted on 17 populations of C. edule and 13 populations of C. glaucum using a 506 bp fragment of mitochondrial DNA (COI). We tested the hypothesis that differences in habitat types and life history are reflected in the genetic structure patterns of these two cockles. Indeed substantial differences in population genetic structures between them are revealed. Genetic diversity within C. glaucum populations decreases northwards as a consequence of post-glacial (re)colonization from southern refugia, while C. edule displays an opposite pattern indicating survival in glacial refuges in the northern Atlantic. Among populations within geographic groups, genetic differentiation is low in C. edule, probably as a result of larval dispersal with coastal currents, while it is extremely high in C. glaucum, best explained by the fragmented habitats. Interestingly, long distance divergence is less expressed in C. glaucum than in C. edule, which supports the speculation that migrating birds (frequently observed in lagoons) may occasionally transport the former more often or more efficiently than the latter. The approach applied in this study (e.g., rarefaction procedure, selection of samples of both species from the same regions) enabled a new and reliable comparative analysis of the existing raw

  13. Cross-habitat interactions among bivalve species control community structure on intertidal flats.

    PubMed

    Donadi, Serena; van der Heide, Tjisse; van der Zee, Els M; Eklöf, Johan S; van de Koppel, Johan; Weerman, Ellen J; Piersma, Theunis; Olff, Han; Eriksson, Britas Klemens

    2013-02-01

    Increasing evidence shows that spatial interactions between sedentary organisms can structure communities and promote landscape complexity in many ecosystems. Here we tested the hypothesis that reef-forming mussels (Mytilus edulis L.), a dominant intertidal ecosystem engineer in the Wadden Sea, promote abundances of the burrowing bivalve Cerastoderma edule L. (cockle) in neighboring habitats at relatively long distances coastward from mussel beds. Field surveys within and around three mussel beds showed a peak in cockle densities at 50-100 m toward the coast from the mussel bed, while cockle abundances elsewhere in the study area were very low. Field transplantation of cockles showed higher survival of young cockles (2-3 years old) and increased spat fall coastward of the mussel bed compared to within the bed and to areas without mussels, whereas growth decreased within and coastward of the mussel bed. Our measurements suggest that the observed spatial patterns in cockle numbers resulted from (1) inhibition effects by the mussels close to the beds due to preemptive algal depletion and deteriorated sediment conditions and (2) facilitation effects by the mussels farther away from the beds due to reduction of wave energy. Our results imply that these spatial, scale-dependent interactions between reef-forming ecosystem engineers and surrounding communities of sedentary benthic organisms can be an important determinant of the large-scale community structure in intertidal ecosystems. Understanding this interplay between neighboring communities of sedentary species is therefore essential for effective conservation and restoration of soft-bottom intertidal communities. PMID:23691667

  14. Climate change impacts on potential recruitment in an ecosystem engineer.

    PubMed

    Morgan, Emer; O' Riordan, Ruth M; Culloty, Sarah C

    2013-03-01

    Climate variability and the rapid warming of seas undoubtedly have huge ramifications for biological processes such as reproduction. As such, gametogenesis and spawning were investigated at two sites over 200 km apart on the south coast of Ireland in an ecosystem engineer, the common cockle, Cerastoderma edule. Both sites are classed as Special Areas of Conservation (SACs), but are of different water quality. Cerastoderma edule plays a significant biological role by recycling nutrients and affecting sediment structure, with impacts upon assemblage biomass and functional diversity. It plays a key role in food webs, being a common foodstuff for a number of marine birds including the oystercatcher. Both before and during the study (early 2010-mid 2011), Ireland experienced its two coldest winters for 50 years. As the research demonstrated only slight variation in the spawning period between sites, despite site differences in water and environmental quality, temperature and variable climatic conditions were the dominant factor controlling gametogenesis. The most significant finding was that the spawning period in the cockle extended over a greater number of months compared with previous studies and that gametogenesis commenced over winter rather than in spring. Extremely cold winters may impact on the cockle by accelerating and extending the onset and development of gametogenesis. Whether this impact is positive or negative would depend on the associated events occurring on which the cockle depends, that is, presence of primary producers and spring blooms, which would facilitate conversion of this extended gametogenesis into successful recruitment. PMID:23532482

  15. Climate change impacts on potential recruitment in an ecosystem engineer

    PubMed Central

    Morgan, Emer; O' Riordan, Ruth M; Culloty, Sarah C

    2013-01-01

    Climate variability and the rapid warming of seas undoubtedly have huge ramifications for biological processes such as reproduction. As such, gametogenesis and spawning were investigated at two sites over 200 km apart on the south coast of Ireland in an ecosystem engineer, the common cockle, Cerastoderma edule. Both sites are classed as Special Areas of Conservation (SACs), but are of different water quality. Cerastoderma edule plays a significant biological role by recycling nutrients and affecting sediment structure, with impacts upon assemblage biomass and functional diversity. It plays a key role in food webs, being a common foodstuff for a number of marine birds including the oystercatcher. Both before and during the study (early 2010–mid 2011), Ireland experienced its two coldest winters for 50 years. As the research demonstrated only slight variation in the spawning period between sites, despite site differences in water and environmental quality, temperature and variable climatic conditions were the dominant factor controlling gametogenesis. The most significant finding was that the spawning period in the cockle extended over a greater number of months compared with previous studies and that gametogenesis commenced over winter rather than in spring. Extremely cold winters may impact on the cockle by accelerating and extending the onset and development of gametogenesis. Whether this impact is positive or negative would depend on the associated events occurring on which the cockle depends, that is, presence of primary producers and spring blooms, which would facilitate conversion of this extended gametogenesis into successful recruitment. PMID:23532482

  16. Natural selection by pulsed predation: survival of the thickest.

    PubMed

    Bijleveld, Aller I; Twietmeyer, Sönke; Piechocki, Julia; van Gils, Jan A; Piersma, Theunis

    2015-07-01

    Selective predation can lead to natural selection in prey populations and may alleviate competition among surviving individuals. The processes of selection and competition can have substantial effects on prey population dynamics, but are rarely studied simultaneously. Moreover, field studies of predator-induced short-term selection pressures on prey populations are scarce. Here we report measurements of density dependence in body composition in a bivalve prey (edible cockle, Cerastoderma edule) during bouts of intense predation by an avian predator (Red Knot, Calidris canutus). We measured densities, patchiness, morphology, and body composition (shell and flesh mass) of cockles in a quasi-experimental setting, i.e., before and after predation in three similar plots of 1 ha each, two of which experienced predation, and one of which remained unvisited in the course of the short study period and served as a reference. An individual's shell and flesh mass declined with cockle density (negative density dependence). Before predation, cockles were patchily distributed. After predation, during which densities were reduced by 78% (from 232 to 50 cockles/m2), the patchiness was substantially reduced, i.e., the spatial distribution was homogenized. Red Knots selected juvenile cockles with an average length of 6.9 ± 1.0 mm (mean ± SD). Cockles surviving predation had heavier shells than before predation (an increase of 21.5 percentage points), but similar flesh masses. By contrast, in the reference plot shell mass did not differ statistically between initial and final sampling occasions, while flesh mass was larger (an increase of 13.2 percentage points). In this field study, we show that Red Knots imposed a strong selection pressure on cockles to grow fast with thick shells and little flesh mass, with selection gradients among the highest reported in the literature. PMID:26378316

  17. Seagrass colonization: Knock-on effects on zoobenthic community, populations and individual health

    NASA Astrophysics Data System (ADS)

    Tu Do, V.; de Montaudouin, Xavier; Lavesque, Nicolas; Blanchet, Hugues; Guyard, Hervé

    2011-12-01

    This study provided evidence that Zostera noltii presence affects macrofauna community structure independently from median sediment grain-size and that the notion of ecosystem health is rather subjective: in the present case, we recorded "good health" in terms of seagrass development, "no impact" in terms of macrobenthic biotic indices and "negative effect" for a given key-population. The occurrence and development of a Z. noltii seagrass bed was surveyed at Banc d'Arguin, Arcachon Bay (France), to estimate the modification of the macrozoobenthic community and of the dynamics of a key-population for the local ecosystem, - the cockle Cerastoderma edule. Even though median grain-size of the sediment decreased only at the very end of the survey, i.e. when seagrass totally invaded the area, most of the macrofauna community characteristics (such as abundance and biomass) increased as soon as Z. noltii patches appeared. The structure of the macrofauna community also immediately diverged between sand and seagrass habitats, without however modifying the tested biotic indices (BENTIX, BOPA, AMBI). The health of the cockle population (growth, abundance, recruitment) was impacted by seagrass development. Related parasite communities slowly diverged between habitats, with more parasites in the cockles from seagrass areas. However, the number of parasites per cockle was always insufficient to alter cockle fitness.

  18. Conditional Responses of Benthic Communities to Interference from an Intertidal Bivalve.

    PubMed

    Van Colen, Carl; Thrush, Simon F; Vincx, Magda; Ysebaert, Tom

    2013-01-01

    Habitat-modifying organisms that impact other organisms and local functioning are important in determining ecosystem resilience. However, it is often unclear how the outcome of interactions performed by key species varies depending on the spatial and temporal disturbance context which makes the prediction of disturbance-driven regime shifts difficult. We investigated the strength and generality of effects of the filter feeding cockle Cerastoderma edule on its ambient intertidal benthic physical and biological environment. By comparing the magnitude of the effect of experimental cockle removal between a non-cohesive and a sheltered cohesive sediment in two different periods of the year, we show that the outcome of cockle interference effects relates to differences in physical disturbance, and to temporal changes in suspended sediment load and ontogenetic changes in organism traits. Interference effects were only present in the cohesive sediments, though the effects varied seasonally. Cockle presence decreased only the density of surface-dwelling species suggesting that interference effects were particularly mediated by bioturbation of the surface sediments. Furthermore, density reductions in the presence of cockles were most pronounced during the season when larvae and juveniles were present, suggesting that these life history stages are most vulnerable to interference competition. We further illustrate that cockles may enhance benthic microalgal biomass, most likely through the reduction of surface-dwelling grazing species, especially in periods with high sediment load and supposedly also high bioturbation rates. Our results emphasize that the physical disturbance of the sediment may obliterate biotic interactions, and that temporal changes in environmental stressors, such as suspended sediments, may affect the outcome of key species interference effects at the local scale. Consequently, natural processes and anthropogenic activities that change bed shear stress

  19. Conditional Responses of Benthic Communities to Interference from an Intertidal Bivalve

    PubMed Central

    Van Colen, Carl; Thrush, Simon F.; Vincx, Magda; Ysebaert, Tom

    2013-01-01

    Habitat-modifying organisms that impact other organisms and local functioning are important in determining ecosystem resilience. However, it is often unclear how the outcome of interactions performed by key species varies depending on the spatial and temporal disturbance context which makes the prediction of disturbance-driven regime shifts difficult. We investigated the strength and generality of effects of the filter feeding cockle Cerastoderma edule on its ambient intertidal benthic physical and biological environment. By comparing the magnitude of the effect of experimental cockle removal between a non-cohesive and a sheltered cohesive sediment in two different periods of the year, we show that the outcome of cockle interference effects relates to differences in physical disturbance, and to temporal changes in suspended sediment load and ontogenetic changes in organism traits. Interference effects were only present in the cohesive sediments, though the effects varied seasonally. Cockle presence decreased only the density of surface-dwelling species suggesting that interference effects were particularly mediated by bioturbation of the surface sediments. Furthermore, density reductions in the presence of cockles were most pronounced during the season when larvae and juveniles were present, suggesting that these life history stages are most vulnerable to interference competition. We further illustrate that cockles may enhance benthic microalgal biomass, most likely through the reduction of surface-dwelling grazing species, especially in periods with high sediment load and supposedly also high bioturbation rates. Our results emphasize that the physical disturbance of the sediment may obliterate biotic interactions, and that temporal changes in environmental stressors, such as suspended sediments, may affect the outcome of key species interference effects at the local scale. Consequently, natural processes and anthropogenic activities that change bed shear stress

  20. Comparative concentrations of brevetoxins PbTx-2, PbTx-3, BTX-B1 and BTX-B5 in cockle, Austrovenus stutchburyi, greenshell mussel, Perna canaliculus, and Pacific oyster, Crassostrea gigas, involved neurotoxic shellfish poisoning in New Zealand.

    PubMed

    Ishida, Hitoshi; Nozawa, Akira; Nukaya, Haruo; Tsuji, Kuniro

    2004-06-01

    Previously, we found brevetoxins PbTx-3, BTX-B5 and BTX-B1 in cockle, Austrovenus (A.) stutchburyi, PbTx-2, PbTx-3 and BTX-B1 in Pacific oyster, Crassostrea (C.) gigas and PbTx-3 and BTX-B1 in greenshell mussel, Perna (P.) canaliculus following outbreak of neurotoxic shellfish poisoning (NSP) in New Zealand by isolation and/or liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). In this study, procedures for quantitative determination of PbTx-2 and BTX-B5 were developed and those for PbTx-3 and BTX-B1 were further examined by LC-MS/MS. In mass spectrometry with an electrospray ionization interface operating in the positive or negative ion mode, the protonated ions [M+H]+ of PbTx-2 (m/z 895), [M+H]+ of PbTx-3 (m/z 897), [M-H]- of BTX-B5 (m/z 909), and [M-Na]- of BTX-B1 (m/z 1016) were generated abundantly, when 0.1% formic acid-acetonitrile was used as the mobile phase for column chromatography. The product ions of m/z 877, 725, 111 and 80 from PbTx-2, PbTx-3, BTX-B5 and BTX-B1 were identified, respectively, allowing unambiguous confirmation of these toxins by selective reaction monitoring LC-MS/MS analysis. High levels of PbTx-3 and BTX-B5 were detected in C. gigas, of PbTx-3, BTX-B1 and BTX-B5 in A. stutchburyi, and of PbTx-2, PbTx-3 and BTX-B5 in P. canaliculus by this LC-MS/MS method. PMID:15284012

  1. Macrozoobenthos on an intertidal mudflat in the Danish Wadden Sea: Comparisons of surveys made in the 1930s, 1940s and 1980s

    NASA Astrophysics Data System (ADS)

    Jensen, K. Thomas

    1992-12-01

    To assess whether long-term faunal changes have occurred on intertidal flats in the Danish Wadden Sea, results of faunal surveys in the Skallingen area during the 1930s, 1940s and 1980s were compared. Since the earlier studies, two species have disappeared ( Scrobicularia plana and Petricola pholadiformis) and two have invaded the area ( Tharyx killariensis and Ensis americanus). This is, however, not a local event as species changes have occurred on a larger scale (Wadden Sea region). Comparison of abundance data did not provide evidence of changes from the 1930s until the 1980s. Spatio-temporal fluctuations in two dominant species, the mudsnail Hydrobia ulvae and the cockle Cerastoderma edule chosen for closer examination, could be explained by natural processes. Growth data on cockles from the 1930s and the 1980s matched perfectly. During both periods, cockles showed a much lower growth rate than generally reported from the Wadden Sea, while at the same time they occurred at high densities (>2000 ind·m-2). Intraspecific competition among cockles is suspected as being a major cause of the low growth rates. Estimates of secondary production and P/B-ratios of cockles were also in general agreement during the 1930s and the 1980s when corrected for differences in the age structure of the cockle populations. With the possible exception of Mytilus edulis, which according to some observations has extended its range along the low-water line, the present comparison failed to demonstrate long-term faunal changes caused by increased eutrophication. This results is expected to be representative for intertidal flats not exposed to direct impacts from terrestrial run-offs and waste-water discharges.

  2. Do pharmaceuticals bioaccumulate in marine molluscs and fish from a coastal lagoon?

    PubMed

    Moreno-González, R; Rodríguez-Mozaz, S; Huerta, B; Barceló, D; León, V M

    2016-04-01

    The bioaccumulation of 20 pharmaceuticals in cockle (Cerastodema glaucum), noble pen shell (Pinna nobilis), sea snail (Murex trunculus), golden grey mullet (Liza aurata) and black goby (Gobius niger) was evaluated, considering their distribution throughout the Mar Menor lagoon and their variations in spring and autumn 2010. The analytical procedure was adapted for the different matrices as being sensitive and reproducible. Eighteen out of the 20 compounds analysed were found at low ngg(-1) in these species throughout the lagoon. Hydrochlorothiazide and carbamazepine were detected in all species considered. The bioaccumulation of pharmaceuticals was heterogeneous in the lagoon, with a higher number of pharmaceuticals being detected in fish (18) than in wild molluscs (8), particularly in golden grey mullet muscle (16). В-blockers and psychiatric drugs were preferentially bioccumulated in fish and hydrochlorothiazide was also confirmed in caged clams. The higher detection frequency and concentrations found in golden grey mullet suggested that mugilids could be used as an indicator of contamination by pharmaceuticals in coastal areas. To the best of our knowledge, this is the first study that shows data about hydrochlorothiazide, levamisole and codeine in wild marine biota. PMID:26775009

  3. The separate and combined effects of epibenthic predation and presence of macro-infauna on the recruitment success of bivalves in shallow soft-bottom areas on the Swedish west coast

    NASA Astrophysics Data System (ADS)

    Flach, E. C.

    2003-02-01

    Previous studies have shown a high year-to-year variability in recruitment success of bivalves. Especially after mild winters recruitment was generally low, but the lower egg production after mild winters in Macoma balthica could only explain 7% of its recruitment variance. In the present study, I tested the hypothesis that the combined effect of a high predation pressure together with a high abundance of adult macrofauna contributes to an explanation of the low recruitment success of bivalves after mild winters. In field experiments in shallow soft-bottom bays at the Swedish west coast, adult benthic fauna (mainly consisting of lugworms Arenicola marina and cockles Cerastoderma edule) was removed and predators (mainly shrimps Crangon crangon and crabs Carcinus maenas) were excluded in some plots/cages, whereas in other plots/cages high densities of adult lugworms or cockles and predators were present. Both the absence of adult macrofauna and the absence of predators increased recruitment success, but the effect of the combined absence of adult macrofauna and predators enhanced recruitment success even more. The combined presence of high macrofauna densities and high predation pressure reduced the recruitment success for Mya arenaria by about 80% compared to the situation in which adult macrofauna and predators were absent. For C. edule, spat densities the reduction was nearly 90% and for Tellinacea spat even about 95%. Thus failure in recruitment success after a mild winter can to a large extent be explained by the presence of high densities of adult macrofauna combined with high predation pressure.

  4. Distribution of aliphatic compounds in bivalve mollusks from Galicia after the Prestige oil spill: spatial and temporal trends.

    PubMed

    Carro, N; Cobas, J; Maneiro, J

    2006-03-01

    The content and distribution of n-alkane (C8-C35) and isoprenoid (pristane and phytane) hydrocarbons were investigated in two species of bivalve mollusk, mussel (Mytilus galloprovincialis) and cockle (Cerastoderma edule), collected at different points of the Galicia littoral zone during the period from December 2002 to February 2003 (after the Prestige oil spill). Samples were analyzed by high-resolution gas chromatography equipped with a flame ionization detector. The highest levels were found in mussels and cockles coming from two estuarine bays, Rías de Arousa and Vigo. Hydrocarbons with carbon chain length > 30 were detected and determined in all samples. The abundance of these hydrocarbons in biota could be interpreted with regard to the feeding and living habits. Chemometric techniques have been employed to analyze data and determine the potential source of hydrocarbon contamination. Differences between mussels and cockles were observed in relation to aliphatic content. According to the data analysis, the main source of hydrocarbon contamination of investigated samples seems to be more related to the intense traffic of vessels in these estuarine bays than to the Prestige oil spill. PMID:16253223

  5. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality.

    PubMed

    Bijleveld, Allert I; MacCurdy, Robert B; Chan, Ying-Chi; Penning, Emma; Gabrielson, Rich M; Cluderay, John; Spaulding, Eric L; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; Brugge, Maarten; van Gils, Jan A; Winkler, David W; Piersma, Theunis

    2016-04-13

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The 'functional response' couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cockles Cerastoderma edule) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knots Calidris canutus). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators. PMID:27053747

  6. Increased mortality in alternative bivalve prey during a period when the tidal flats of the Dutch Wadden Sea were devoid of mussels

    NASA Astrophysics Data System (ADS)

    Beukema, J. J.

    In the course of 1990, stocks of mussels ( Mytilus edulis) declined to unprecedentedly low levels in the Dutch Wadden Sea. Hardly a wild mussel bed was left on the tidal flats as a consequence of three years (1988, 1989, and 1990) with failing recruitment and intensive fishing for seed mussels. During these three years, recruitment of cockles ( Cerastoderma edule) also failed, whereas fishing was continued. Bird species taking these bivalves as staple food, the oystercatcher ( Haematopus ostralegus) and the eider ( Somateria mollissima), experienced food shortage. Significant numbers of eiders left the Dutch Wadden Sea area or died, whereas oystercatchers remained abundant trhoughout the winter in most of the Dutch Wadden Sea. Alternative prey species of oystercatchers experienced unsually high mortality rates in the appropriate size classes. This was so in all other common species of bivalves, viz. first-year and older cockles, adult Macoma balthica, and juvenile Mya arenaria. This led to minimal stocks of food for oystercatchers in the late winter of 1991. In March 1991, cockles were depleted and the combined stocks Mya and Macoma would soon have run out of food supply to the overwintering oystercatcher population. Apparently, oystercatchers are able to reduce the stocks of their various bivalve prey species to very low levels.

  7. Relative sensitivity of two marine bivalves for detection of genotoxic and cytotoxic effects: a field assessment in the Tamar Estuary, South West England.

    PubMed

    Dallas, Lorna J; Cheung, Victoria V; Fisher, Andrew S; Jha, Awadhesh N

    2013-04-01

    The input of anthropogenic contaminants to the aquatic environment is a major concern for scientists, regulators and the public. This is especially relevant in areas such as the Tamar valley in SW England, which has a legacy of contamination from industrial activity in the nineteenth and twentieth centuries. Following on from previous laboratory validation studies, this study aimed to assess the relationship between genotoxic and cytotoxic responses and heavy metal concentrations in two bivalve species sampled from locations along the Tamar estuary. Adult cockles, Cerastoderma edule, and blue mussels, Mytilus edulis, were sampled from five locations in the Tamar and one reference location on the south Devon coast. Bivalve haemocytes were processed for comet and neutral red retention (NRR) assays to determine potential genotoxic and cytotoxic effects, respectively. Sediment and soft tissue samples were analysed for metal content by inductively coupled plasma mass spectrometry. Sediment concentrations were consistent with the physico-chemical nature of the Tamar estuary. A significant correlation (P = 0.05) was found between total metal concentration in sediment and C. edule soft tissues, but no such correlation was found for M. edulis samples. DNA damage was elevated at the site with highest Cr concentrations for M. edulis and at the site with highest Ni and Pb concentrations for C. edule. Analysis of NRR revealed a slight increase in retention time at one site, in contrast to comet data. We conclude that the comet assay is a reliable indicator of genotoxic damage in the field for both M. edulis and C. edule and discuss reasons for the apparent discrepancy with NRR. PMID:22890867

  8. Habitat and transmission--effect of tidal level and upstream host density on metacercarial load in an intertidal bivalve.

    PubMed

    Thieltges, D W

    2007-04-01

    Transmission of parasites may be mediated by their habitat, consisting of abiotic and biotic components. I investigated the effect of 2 important habitat components in intertidal ecosystems, tidal level (abiotic) and density of upstream hosts (biotic), on the transmission of trematode cercariae to cockle (Cerastoderma edule) hosts. A field survey showed no general trend in metacercarial loads of cockles regarding tidal level but species-dependent reactions. Parasites originating from Littorina littorea (Himasthla elongata, Renicola roscovita) showed highest infection levels in the low intertidal while parasites originating from Hydrobia ulvae (H. continua, H. interrupta) showed highest infection levels in the mid-intertidal. This reflected the density of upstream hosts at both tidal levels and positive relationships between the density of upstream hosts and metacercarial load in cockles suggested the biotic habitat component to be the dominant factor in transmission. This was confirmed by a field experiment, manipulating tidal level and the density of infected upstream snail hosts. While tidal level had no significant effect on the number of metacercariae of H. elongata acquired by cockles, the effect of upstream host density was strong. In conclusion, although tidal level usually is a very important abiotic habitat component in intertidal ecosystems leading to conspicuous zonation patterns in free-living organisms, it seems of minor importance for trematode transmission. In contrast, the biotic component upstream host density is suggested to be the dominant predictor for trematode transmission to second intermediate hosts. Assessing the relative importance of abiotic and biotic habitat components in transmission is vital for the understanding of transmission processes in the field. PMID:17076926

  9. Size, distribution and sediment biodeposition of prolific bivalves in small estuaries

    NASA Astrophysics Data System (ADS)

    Callaway, Ruth; Grenfell, Suzanne; Bertelli, Chiara; Mendzil, Anouska; Moore, Jon

    2014-10-01

    The growth and distribution of bivalves in estuaries is generally driven by access to food, hydrodynamic forces and sedimentary conditions that facilitate recruitment and allow persistent settlement. Factors such as site elevation or sediment properties have a significant impact, but there are few studies quantifying the relative importance of different factors in an entire estuary. We carried out an estuary-wide survey of the cockle Cerastoderma edule L. by sampling 343 sites in a small estuary, the Burry Inlet in South Wales, UK. We determined the extent to which site elevation, as an indicator for the duration of feeding, sediment properties and position inside the estuary, explained variation in the size and density of the bivalve. We also analysed the production of faeces and pseudo-faeces per cockle. The population consisted almost entirely of 1-year old cockles, the average size was 14.7 ± 2.7 mm and the average density was 56 ± 189 cockles 0.1 m-2 (mean ± SD). Altogether 37% of the variation in size was explained by two factors: elevation of site (15%) and amount of clay & silt in sediments (22%). Variation in density appeared to play no significant role in determining size. Density was significantly linked to sediment properties (32%) and position inside the estuary (4%). Sediment biodeposition, the amount of material discharged per cockle, was 0.032 ± 0.017 g dry weight, the whole population thereby producing an estimated 387 tonnes of faeces and pseudo-faeces in the entire estuary per day. The study confirmed that access to food is a principal driver of growth, but the relatively small proportion of the variation in size explained by site elevation highlights that other factors play an important role. Sediment characteristics in particular were of importance to variation in size as well as density. It seems plausible that sediment properties were a proxy for factors such as bedload movement and exposure, which are more likely causal factors for

  10. Is porewater an important route of metals to macrobenthic organisms? Example of an estuarine field study

    SciTech Connect

    Srinetr, V.; Baeyens, W.; Ysebaert, T.; Meire, P.

    1995-12-31

    Porewater is recently hypothesized as a direct and important route of metal exposure to benthic organisms. However, only a few research studies clearly indicate its usefulness in monitoring and assessment of metal pollution. This study aims to answer whether porewater is really a significant route of metals to macrobenthic organisms in a natural sediment environment. Therefore, seven intertidal locations along the salinity gradient of the Schelde estuary (Belgium-The Netherlands) were investigated during a one year period (1993--1994). Metal analysis was performed on monthly samples of dominant macrobenthic species including the bivalves Macoma balthica, Scrobicularia plana, Cerastodema edule and Mya arenaria, the amphipod Corophium volutator and the polychaete Nereis diversicolor. Metal analysis includes manganese, chromium, nickel, copper, zinc, arsenic, selenium, cadmium and lead. The results show temporal and spatial variation of metals in both macrobenthic organisms and porewater. Levels of some metals in porewater, for example cadmium, lead, and copper are higher in winter months than in summer months in coherence with higher levels found in some benthic species. For some benthic species, metal contents were directly related to metal concentrations in porewater. However, no firm conclusion can be drawn that porewater is the only main source of bioavailable metals to benthic organisms and all metal species in porewater are bioavailable. In order to understand metal bioavailability in the sediment environment, a combination of information from a multidisciplinary approach (geochemistry, benthic ecology and toxicology) is needed. In fact, this study fits within the framework of a Triad-approach, conducted on sediments of the Schelde estuary.

  11. Bioaccumulation of mycotoxins by shellfish: contamination of mussels by metabolites of a Trichoderma koningii strain isolated in the marine environment.

    PubMed

    Sallenave, C; Pouchus, Y F; Bardouil, M; Lassus, P; Roquebert, M F; Verbist, J F

    1999-01-01

    To determine whether toxic metabolites produced by fungi could cause shellfish toxicities, mussels were contaminated in laboratory conditions by sterile filtrates of a liquid culture of a strain of the fungus Trichoderma koningii previously isolated from a shellfish, the cockle (Cerastoderma edule). Mussels were kept in aerated natural seawater and fed with a culture of the microalga Isochrysis galbana, to which a filtrate of liquid fungal culture was added. Mussels were exposed to contamination for 7 days at 16 or 20 degrees C and extractions were then performed and their activity tested on blowfly larvae. The same toxicity was found in the fungal filtrate and the shellfish, indicating bioaccumulation. The digestive gland was the most toxic part of the mussel, confirming contamination by filtration. Treated mussels produced a mucus which appeared to be a means of eliminating toxic metabolites. PMID:9920482

  12. Now an empty mudflat: past and present benthic abundances in the western Dutch Wadden Sea

    NASA Astrophysics Data System (ADS)

    Kraan, Casper; Dekinga, Anne; Piersma, Theunis

    2011-03-01

    The benthic fauna of two areas in the western Dutch Wadden Sea, Posthuiswad and Staart van Schieringhals, was described in 1930-1960 and again between 1996 and 2005. Here, we document the changes. Whereas both areas formerly had high densities of species that biogenically structured the intertidal mudflats such as mussels Mytilus edulis and cockles Cerastoderma edule, by 1996 they had shown a tenfold decrease in the densities of molluscs, with no recovery till 2005. Although the number of species of polychaetes and crustaceans may not have changed much, their relative abundance did. Nowadays, more polychaete species are common than before. We briefly discuss whether the changes in benthic community composition could be due to industrial fishery practices or eutrophication effects.

  13. Profiles of paralytic shellfish toxins in bivalves of low and elevated toxicities following exposure to Gymnodinium catenatum blooms in Portuguese estuarine and coastal waters.

    PubMed

    Botelho, Maria João; Vale, Carlos; Ferreira, João Gomes

    2015-11-01

    Profiles of paralytic shellfish toxins (PSTs) were examined in 405 composite samples of Mytilus spp., Cerastoderma edule, Donax trunculus and Spisula solida collected between 2007 and 2012 from natural production areas in two estuaries (Aveiro and Mondego), two coastal lagoons (Óbidos and Formosa), and three open coastal areas (Aguda, Comporta and Culatra). Toxin concentrations were obtained from the biotoxin monitoring programme database. Episodes of PST toxicity in Portugal have been associated with Gymnodinium catenatum blooms. Toxin profiles for each species showed no trend over the surveyed years. In general, profiles differ only slightly among areas, except for Óbidos. However, toxin profiles in bivalves varied between low and elevated toxicities, corresponding to below and above the PST regulatory limit, respectively. The ratio R1=(C1+2):B1, which were the main toxins produced by G. catenatum cells, decreased considerably between elevated and low toxicity cockles, indicating the elimination of C1+2 or conversion of compounds into B1. R2=[(dcSTX)+(dcGTX2+3)]:[(C1+2)+(B1)], which represents the ratio of minor to major toxins in G. catenatum cells, increased substantially in wedge clams (D. trunculus) of low toxicity and less markedly in cockles (C. edule) and mussels (Mytilus spp.). These differences are interpreted as the predominance of a biotransformation phase after exposure to the algal bloom. The toxin profile of surf clams (S. solida) was dominated by decarbamoyl compounds, reflecting intense biotransformation during exposure to blooms. The higher ratio R2 in low toxicity samples suggests that elimination of the produced decarbamoyl toxins was slower than biotransformation. PMID:25616737

  14. Estimation of Density-Dependent Mortality of Juvenile Bivalves in the Wadden Sea

    PubMed Central

    Andresen, Henrike; Strasser, Matthias; van der Meer, Jaap

    2014-01-01

    We investigated density-dependent mortality within the early months of life of the bivalves Macoma balthica (Baltic tellin) and Cerastoderma edule (common cockle) in the Wadden Sea. Mortality is thought to be density-dependent in juvenile bivalves, because there is no proportional relationship between the size of the reproductive adult stocks and the numbers of recruits for both species. It is not known however, when exactly density dependence in the pre-recruitment phase occurs and how prevalent it is. The magnitude of recruitment determines year class strength in bivalves. Thus, understanding pre-recruit mortality will improve the understanding of population dynamics. We analyzed count data from three years of temporal sampling during the first months after bivalve settlement at ten transects in the Sylt-Rømø-Bay in the northern German Wadden Sea. Analyses of density dependence are sensitive to bias through measurement error. Measurement error was estimated by bootstrapping, and residual deviances were adjusted by adding process error. With simulations the effect of these two types of error on the estimate of the density-dependent mortality coefficient was investigated. In three out of eight time intervals density dependence was detected for M. balthica, and in zero out of six time intervals for C. edule. Biological or environmental stochastic processes dominated over density dependence at the investigated scale. PMID:25105293

  15. Estimation of density-dependent mortality of juvenile bivalves in the Wadden Sea.

    PubMed

    Andresen, Henrike; Strasser, Matthias; van der Meer, Jaap

    2014-01-01

    We investigated density-dependent mortality within the early months of life of the bivalves Macoma balthica (Baltic tellin) and Cerastoderma edule (common cockle) in the Wadden Sea. Mortality is thought to be density-dependent in juvenile bivalves, because there is no proportional relationship between the size of the reproductive adult stocks and the numbers of recruits for both species. It is not known however, when exactly density dependence in the pre-recruitment phase occurs and how prevalent it is. The magnitude of recruitment determines year class strength in bivalves. Thus, understanding pre-recruit mortality will improve the understanding of population dynamics. We analyzed count data from three years of temporal sampling during the first months after bivalve settlement at ten transects in the Sylt-Rømø-Bay in the northern German Wadden Sea. Analyses of density dependence are sensitive to bias through measurement error. Measurement error was estimated by bootstrapping, and residual deviances were adjusted by adding process error. With simulations the effect of these two types of error on the estimate of the density-dependent mortality coefficient was investigated. In three out of eight time intervals density dependence was detected for M. balthica, and in zero out of six time intervals for C. edule. Biological or environmental stochastic processes dominated over density dependence at the investigated scale. PMID:25105293

  16. Biological impact of eutrophication in the bay of somme and the induction and impact of anoxia

    NASA Astrophysics Data System (ADS)

    Desprez, M.; Rybarczyk, H.; Wilson, J. G.; Ducrotoy, J. P.; Sueur, F.; Olivesi, R.; Elkaim, B.

    The first effects of eutrophication in the Bay of Somme became apparent in the years 1982-1985, when the cockle population collapsed. Areas of high mortality were mapped. Following exceptionally high summer temperatures, other effects were seen in 1982, 1983 and 1989, notably a mass mortality of the benthos. It appeared that the mortality of the benthos was a direct result of anoxia in the water promoted by phytoplankton blooms which were due to high nitrogen levels (nitrates from river and land runoff; ammonium from estuarine bivalve populations). Effects from the change in the benthic community (the disappearance of Cerastoderma edule and the proliferation of Pygospio elegans) were also apparent higher up in the food chain, viz. changes in the diet of the two main predators of the bivalve, the oystercatcher ( Haematopus ostralegus) and the common gull ( Larus canus). Following respirometry measurements of the water, sediment and the major macrobenthic species ( Cerastoderma edule, Macoma balthica, Nereis diversicolor, Hydrobia ulvae), a model for anoxia was constructed.

  17. Connectivity, neutral theories and the assessment of species vulnerability to global change in temperate estuaries

    NASA Astrophysics Data System (ADS)

    Chust, Guillem; Albaina, Aitor; Aranburu, Aizkorri; Borja, Ángel; Diekmann, Onno E.; Estonba, Andone; Franco, Javier; Garmendia, Joxe M.; Iriondo, Mikel; Muxika, Iñigo; Rendo, Fernando; Rodríguez, J. Germán; Ruiz-Larrañaga, Otsanda; Serrão, Ester A.; Valle, Mireia

    2013-10-01

    One of the main adaptation strategies to global change scenarios, aiming to preserve ecosystem functioning and biodiversity, is to maximize ecosystem resilience. The resilience of a species metapopulation can be improved by facilitating connectivity between local populations, which will prevent demographic stochasticity and inbreeding. This investigation estimated the degree of connectivity among estuarine species along the north-eastern Iberian coast, in order to assess community vulnerability to global change scenarios. To address this objective, two connectivity proxy types have been used based upon genetic and ecological drift processes: 1) DNA markers for the bivalve cockle (Cerastoderma edule) and seagrass Zostera noltei, and 2) the decrease in the number of species shared between two sites with geographic distance. Neutral biodiversity theory predicts that dispersal limitation modulates this decrease, and this has been explored in estuarine plants and macroinvertebrates. Results indicate dispersal limitation for both saltmarsh plants and seagrass beds community and Z. noltei populations; this suggests they are especially vulnerable to expected climate changes on their habitats. In contrast, unstructured spatial pattern found in macroinvertebrate communities and in C. edule genetic populations in the area suggests that estuarine soft-bottom macroinvertebrates with planktonic larval dispersal strategies may have a high resilience capacity to moderate changes within their habitats. Our findings allow environmental managers to prioritize the most vulnerable species and habitats to be restored.

  18. Prevalence and Genetic Diversity of Human Sapoviruses in Shellfish from Commercial Production Areas in Galicia, Spain

    PubMed Central

    Varela, Miguel F.; Polo, David

    2015-01-01

    The prevalence of human forms of Sapovirus, an emerging pathogen of human gastroenteritis, was investigated in an 18-month survey from class B mollusc-harvesting areas in two Galician rias (northwest Spain). The detection and quantification of Sapovirus was performed by reverse transcription-real-time PCR, according to the recently developed standard method ISO/TS 15216-1:2013, and genotyping by reverse transcription-nested PCR. The bivalve species studied were wild and cultured mussels (Mytilus galloprovincialis), clams (Venerupis philippinarum and Venerupis decussata), and cockles (Cerastoderma edule). Sapovirus was detected in 30 out of 168 samples (17.9%), with cockles being the species with the highest prevalence of positives (28.1%), followed by clams (22.6%), wild mussels (14.3%), and cultured mussels (12.9%). The estuary in the south of the region demonstrated a higher percentage of positive samples (21.8%) than the one in the north (14.4%). Viral contamination levels for the positive samples ranged between 1.9 × 103 and 1.4 × 105 RNA copies/g of digestive tissue. Thirteen Sapovirus sequences could be obtained based on partial capsid gene sequence and were classified into four genotypes: GI.1 (2 samples), GI.2 (8 samples), GIV.1 (2 samples), and GV.1 (1 sample). PMID:26655761

  19. Metal contamination in water, sediment and biota from a semi-enclosed coastal area.

    PubMed

    Aly, Walid; Williams, Ian D; Hudson, Malcolm D

    2013-05-01

    This study identifies and quantifies the spatial variations of metal contamination in water, sediment and biota: the common cockle (Cerastoderma edule) and the Mermaid's glove sponge (Haliclona oculata), within a heavily anthropogenically impacted semi-enclosed estuarine-coastal area with a low ability to disperse and flush contaminants (Poole Harbour, UK). The results showed that metal contamination was detected in all environmental compartments. Water was polluted with As, and Hg sediment metals were mostly within "the possible effect range" in which adverse effects occasionally occurs. Cockles had considerable concentrations of Ni, Ag and Hg in areas close to pollution sources, and sponges accumulate Cu and Zn with very high magnitude. A systematic monitoring approach that includes biological monitoring techniques, which covers all embayments, is needed, and an integrated management of the semi-enclosed coastal zones should be based on the overall hydrological characteristics of these sensitive areas and their ability to self-restore which is different than open coastal zones. PMID:23014922

  20. Sediment segregation by biodiffusing bivalves

    NASA Astrophysics Data System (ADS)

    Montserrat, F.; Van Colen, C.; Provoost, P.; Milla, M.; Ponti, M.; Van den Meersche, K.; Ysebaert, T.; Herman, P. M. J.

    2009-08-01

    The selective processing of sediment fractions (sand and mud; >63 μm and ≤63 μm median grain size) by macrofauna was assessed using two size classes of inert, UV-fluorescent sediment fraction tracers (luminophores). The luminophores were applied to the sediment surface in 16 m 2 replicated plots, defaunated and control, and left to be reworked by infauna for 32 days. As the macrofaunal assemblage in the ambient sediment and the control plots was dominated by the common cockle Cerastoderma edule, this species was used in an additional mesocosm experiment. The diversity, abundance and biomass of the defaunated macrobenthic assemblage did not return to control values within the experimental period. Both erosion threshold and bed elevation increased in the defaunated plots as a response to the absence of macrofauna and an increase in microphytobenthos growth. In the absence of macrobenthos, we observed an accretion of 7 mm sediment, containing ca. 60% mud. Image analysis of the vertical distribution of the different luminophore size classes showed that the cockles preferentially mobilised fine material from the sediment, thereby rendering it less muddy and effectively increasing the sand:mud ratio. Luminophore profiles and budgets of the mesocosm experiment under "no waves-no current" conditions support the field data very well.

  1. Widespread transmission of independent cancer lineages within multiple bivalve species.

    PubMed

    Metzger, Michael J; Villalba, Antonio; Carballal, María J; Iglesias, David; Sherry, James; Reinisch, Carol; Muttray, Annette F; Baldwin, Susan A; Goff, Stephen P

    2016-06-30

    Most cancers arise from oncogenic changes in the genomes of somatic cells, and while the cells may migrate by metastasis, they remain within that single individual. Natural transmission of cancer cells from one individual to another has been observed in two distinct cases in mammals (Tasmanian devils and dogs), but these are generally considered to be rare exceptions in nature. The discovery of transmissible cancer in soft-shell clams (Mya arenaria) suggested that this phenomenon might be more widespread. Here we analyse disseminated neoplasia in mussels (Mytilus trossulus), cockles (Cerastoderma edule), and golden carpet shell clams (Polititapes aureus) and find that neoplasias in all three species are attributable to independent transmissible cancer lineages. In mussels and cockles, the cancer lineages are derived from their respective host species; however, unexpectedly, cancer cells in P. aureus are all derived from Venerupis corrugata, a different species living in the same geographical area. No cases of disseminated neoplasia have thus far been found in V. corrugata from the same region. These findings show that transmission of cancer cells in the marine environment is common in multiple species, that it has originated many times, and that while most transmissible cancers are found spreading within the species of origin, cross-species transmission of cancer cells can occur. PMID:27338791

  2. Year-to-year variability in the biomass of macrobenthic animals on tidal flats of the Wadden Sea: How predictable is this food source for birds?

    NASA Astrophysics Data System (ADS)

    Beukema, J. J.; Essink, K.; Michaelis, H.; Zwarts, L.

    The Wadden Sea is important as a stop-over and wintering area for several species of waders, foraging for shorter or longer times on its tidal flats. The size of the food stocks these birds encounter varies from place to place and from year to year. We studied characteristics of the variability in time of such prey stocks, using long-term data series of annual estimates of biomass of macrobenthic animals collected on tidal flats in various parts of the Dutch and German Wadden Sea. Year-to-year fluctuations were stronger in nearly all individual benhos species than in total macrozoobenthic biomass. The various species differed significantly in their year-to-year variability. Everywhere the tellinid bivalve Macoma balthica was relatively stable, whereas species such as the cockle Cerastoderma edule and the polychaetes Lanice conchilega, Nephtys hombergii and Anaitides mucosa fluctuated heavily and rapidly in all parts of the Wadden Sea where they were found. Within species, fluctuations in biomass of individual age or size classes were stronger than those in total biomass of the species. Several species showed minimal biomass values in the same years over vast areas. This synchronization of scarcity was caused particularly by similar responses to winter character, which was each year similar over the entire Wadden Sea. Such similar responses included low over-winter survival during severe winters and recruitment failure after exceptionally mild winters. Immediately after severe winters, such cold-sensitivee species as C. edule, L. conchilega and N. hombegii were scarce all over the Waden Sea, thus liimiting the possibilities for birds to switch to other parts of the Wadden Sea to find their preferred prey in sufficient quantitu. Simultaneous recruitment failure in several important bivalve species ( C. edule, Mytilus edulis, and Mya arenaria limited the possibility for specialized bivalve consumers to switch to alternative prey types in certain years.

  3. Polysaccharide composition of raw and cooked chayote (Sechium edule Sw.) fruits and tuberous roots.

    PubMed

    Shiga, Tânia M; Peroni-Okita, Fernanda Helena Gonçalves; Carpita, Nicholas C; Lajolo, Franco Maria; Cordenunsi, Beatriz Rosana

    2015-10-01

    Chayote is a multipurpose table vegetable widely consumed in Latin America countries. Chayote fruits, leaves and tuberous roots contain complex carbohydrates as dietary fiber and starch, vitamins and minerals. The complex polysaccharides (cell walls and starch) were analyzed in the black and green varieties of chayote fruits as well as in green chayote tuberous root before and after a controlled cooking process to assess changes in their composition and structure. The monosaccharide composition and linkage analysis indicated pectins homogalacturonans and rhamnogalacturonan I backbones constitute about 15-20% of the wall mass, but are heavily substituted with, up to 60% neutral arabinans, galactans, arabinogalactans. The remainder is composed of xyloglucan, glucomannans and galactoglucomannans. Chayote cell-wall polysaccharides are highly stable under normal cooking conditions, as confirmed by the optical microscopy of wall structure. We found also that tuberous roots constitute a valuable additional source of quality starch and fiber. PMID:26076612

  4. The estimation of DEB parameters for various Northeast Atlantic bivalve species

    NASA Astrophysics Data System (ADS)

    van der Veer, Henk W.; Cardoso, Joana F. M. F.; van der Meer, Jaap

    2006-08-01

    Dynamic energy budgets are used for the description of the energy flow through individual organisms from the assimilation of food to the utilisation for maintenance, growth, development and reproduction. In this paper, a procedure for estimation of the parameters of Kooijman's Dynamic Energy Budget (DEB) model is introduced and subsequently parameters are estimated for the following Northeast Atlantic bivalve species: the Baltic clam Macoma balthica (L.), the sandgaper Mya arenaria L., the cockle Cerastoderma edule (L.), the blue mussel Mytilus edulis L. and the Pacifc oyster Crassostrea gigas (Thunberg, 1793). For none of the species, a complete set of parameters could be compiled. A special protocol was developed to account for missing values and to achieve consistency between parameters. Species were similar in their optimal temperature range, as reflected in a common Arrhenius temperature of 5800 K, which corresponds with a Q 10 of 2. Differences between species were observed in width of the optimal temperature range. The taxonomic relatedness between species was reflected in similar volume-specific maintenance costs, costs for growth and almost similar maximum storage density of energy. Species differed in their maximum surface area-specific assimilation rate by a factor of 6 and in the fraction of energy allocated to reproduction (ranging from 0.15 to 0.50). These differences are reflected in the maximum theoretical total shell length of the species, which varied from about 3 cm in M. balthica, 6 cm in C. edule, 15 cm in M. arenaria and M. edulis and 45 cm in C. gigas.

  5. Ingested water equilibrates isotopically with the body water pool of a shorebird with unrivaled water fluxes.

    PubMed

    Visser, G H; Dekinga, A; Achterkamp, B; Piersma, T

    2000-11-01

    We investigated the applicability of (2)H to measure the amount of body water (TBW) and water fluxes in relation to diet type and level of food intake in a mollusk-eating shorebird, the Red Knot (Calidris canutus). Six birds were exposed to eight experimental indoor conditions. Average fractional (2)H turnover rates ranged between 0. 182 day(-1) (SD = 0.0219) for fasting birds and 7.759 day(-1) (SD = 0.4535) for birds feeding on cockles (Cerastoderma edule). Average TBW estimates obtained with the plateau method were within the narrow range of 75.9-85.4 g (or between 64.6 and 70.1% of the body mass). Those obtained with the extrapolation method showed strong day-to-day variations (range 55.7-83.7 g, or between 49.7 and 65.5%). Average difference between the two calculation methods ranged between 0.6% and 36.3%, and this difference was strongly negatively correlated with water flux rate. Average water influx rates ranged between 15.5 g/day (fasting) and 624.5 g/day (feeding on cockles). The latter value is at 26.6 times the allometrically predicted value and is the highest reported to date. Differences in (2)H concentrations between the blood and feces (i.e., biological fractionation) were small but significant (-3.4% when fed a pellet diet, and -1.1% for all the other diets), and did not relate to the rate of water flux (chi(2)(1) = 0.058, P < 0.81). We conclude that the ingested water equilibrated rapidly with the body water pool even in an avian species that shows record water flux rates when living on ingested marine bivalves. PMID:11049863

  6. Eiders Somateria mollissima scavenging behind a lugworm boat

    NASA Astrophysics Data System (ADS)

    Leopold, Mardik F.

    2002-02-01

    The eider is one of the most important molluscivorous birds in the Wadden Sea, where it feeds mainly on blue mussels Mytilus edulis and edible cockles Cerastoderma edule. These prey species are within reach of the birds at all times. Other potential prey of suitable size that are abundantly present, such as several polychaete worms, or the clam Mya arenaria, are taken to a much lesser extent, possibly because they live buried in the sediment and digging them out would take too much effort. Mya may pose another problem because they grow to sizes that prevent eiders from swallowing them. Large Mya also live too deep down in the sediment, but young (small) specimens should be available to eiders. Yet, even these have only rarely been found as prey in eiders in the Wadden Sea. However, diet studies in relation to food abundance have been few, and may have missed prey that do not leave large shell fragments (i.e. in faeces studies). This paper describes observations on eiders taking both Mya and polychaete worms. The eiders fed on these prey in a fashion reminiscent of gulls that scavenge behind fishing vessels: some eiders have learnt to follow professional worm-digging boats that supply a bycatch of molluscs (mainly Mya arenaria) and polychaete worms (mainly Arenicola marina and Nephtys hombergii) .Mya and worms were also the main targets of the eiders that fed in a dense flock close to the boat's stern. Faeces found on the flats at low tide comprised mainly cockle shell fragments, a prey rarely taken by the eiders behind the boat. Faeces studies may thus give a highly biased impression of local eider diet.

  7. BMAA in shellfish from two Portuguese transitional water bodies suggests the marine dinoflagellate Gymnodinium catenatum as a potential BMAA source.

    PubMed

    Lage, Sandra; Costa, Pedro Reis; Moita, Teresa; Eriksson, Johan; Rasmussen, Ulla; Rydberg, Sara Jonasson

    2014-07-01

    The neurotoxin β-N-methylamino-l-alanine (BMAA) and its putative role in multiple neurodegenerative diseases have been intensely studied since 2005 when the toxin was discovered to be produced by worldwide-distributed cyanobacterial species inhabiting terrestrial, marine, brackish, and freshwater ecosystems. Recently, BMAA production was also associated with one eukaryotic group, namely, diatoms, raising questions about its production by other phytoplanktonic groups. To test for BMAA bioavailability in ecosystems where abundant phytoplanktonic blooms regularly occur, samples of filter-feeding shellfish were collected in two Portuguese transitional water bodies. BMAA content in cockles (Cerastoderma edule) collected weekly between September and November 2009 from Ria de Aveiro and at least once a month from May to November from Ria Formosa, fluctuated from 0.079±0.055 to 0.354±0.066μg/g DW and from below the limit of detection to 0.434±0.110μg/g DW, respectively. Simultaneously to BMAA occurrence in cockles, paralytic shellfish toxins were detected in shellfish as a result of Gymnodinium catenatum blooms indicating a possible link between this marine dinoflagellate and BMAA production. Moreover, considerable high BMAA levels, 0.457±0.186μg/g DW, were then determined in a laboratory grown culture of G. catenatum. This work reveals for the first time the presence of BMAA in shellfish from Atlantic transitional water bodies and consubstantiate evidences of G. catenatum as one of the main sources of BMAA in these ecosystems. PMID:24747603

  8. Fruit extract from a Sechium edule hybrid induce apoptosis in leukaemic cell lines but not in normal cells.

    PubMed

    Aguiñiga-Sánchez, Itzen; Soto-Hernández, Marcos; Cadena-Iñiguez, Jorge; Ruíz-Posadas, Lucero del Mar; Cadena-Zamudio, Jorge David; González-Ugarte, Ana Karen; Steider, Benny Weiss; Santiago-Osorio, Edelmiro

    2015-01-01

    The antiproliferative potential of a crude extract from the chayote hybrid H-837-07-GISeM® and its potential for apoptosis induction were assessed in leukaemic cell lines and normal mouse bone marrow mononuclear cells (BM-MNCs). The extract strongly inhibited the proliferation of the P388, J774, and WEHI-3 cell lines (with an IC50 below 1.3 μg·mL(-1)), reduced cell viability, and induced apoptotic body production, phosphatidylserine translocation, and DNA fragmentation. However, the extract had no effect on BM-MNCs. We postulate that these properties make the extract a good candidate for an anti-tumour agent for clinical use. PMID:25611564

  9. Accumulation of Sellafield-derived radiocarbon ((14)C) in Irish Sea and West of Scotland intertidal shells and sediments.

    PubMed

    Tierney, Kieran M; Muir, Graham K P; Cook, Gordon T; MacKinnon, Gillian; Howe, John A; Heymans, Johanna J; Xu, Sheng

    2016-01-01

    The nuclear energy industry produces radioactive waste at various stages of the fuel cycle. In the United Kingdom, spent fuel is reprocessed at the Sellafield facility in Cumbria on the North West coast of England. Waste generated at the site comprises a wide range of radionuclides including radiocarbon ((14)C) which is disposed of in various forms including highly soluble inorganic carbon within the low level liquid radioactive effluent, via pipelines into the Irish Sea. This (14)C is rapidly incorporated into the dissolved inorganic carbon (DIC) reservoir and marine calcifying organisms, e.g. molluscs, readily utilise DIC for shell formation. This study investigated a number of sites located in Irish Sea and West of Scotland intertidal zones. Results indicate (14)C enrichment above ambient background levels in shell material at least as far as Port Appin, 265 km north of Sellafield. Of the commonly found species (blue mussel (Mytilus edulis), common cockle (Cerastoderma edule) and common periwinkle (Littorina littorea)), mussels were found to be the most highly enriched in (14)C due to the surface environment they inhabit and their feeding behaviour. Whole mussel shell activities appear to have been decreasing in response to reduced discharge activities since the early 2000s but in contrast, there is evidence of continuing enrichment of the carbonate sediment component due to in-situ shell erosion, as well as indications of particle transport of fine (14)C-enriched material close to Sellafield. PMID:26555367

  10. Expected changes in the wadden sea benthos in a warmer world: Lessons from periods with mild winters

    NASA Astrophysics Data System (ADS)

    Beukema, J. J.

    Changes observed in the macrozoobenthos at tidal flats in the westernmost part of the Wadden Sea during the 1969-1991 period were used to evaluate effects of mild winters. At least one third of the macrobenthic species in this area is sensitive to low winter temperatures. This has resulted in higher species richness and higher abundance of these species following mild as opposed to normal or cold winters. Negative effects of mild winters include greater weight loss in all bivalves during the winter and low reproductive success in the subsequent summer for various important (bivalve) species. A recent series of three mild winters in close succession (1988-1990, including the two mildest of the century) had profound effects: repeated recruitment failure in the bivalves Mya arenaria and the heavily fished Mytilus edulis and Cerastoderma edule resulted in low standing stocks of these species in the course of 1990. Effects were noted on algal stocks (elevation), other bivalves (higher weights) and predators (food shortage); problems arose particularly in the mussel and cockle fisheries as well as among the eiders ( Somateria mollissima).

  11. Calcium Oxide Derived from Waste Shells of Mussel, Cockle, and Scallop as the Heterogeneous Catalyst for Biodiesel Production

    PubMed Central

    Chaiyut, Nattawut; Worawanitchaphong, Phatsakon

    2013-01-01

    The waste shell was utilized as a bioresource of calcium oxide (CaO) in catalyzing a transesterification to produce biodiesel (methyl ester). The economic and environmen-friendly catalysts were prepared by a calcination method at 700–1,000°C for 4 h. The heterogeneous catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) method. The effects of reaction variables such as reaction time, reaction temperature, methanol/oil molar ratio, and catalyst loading on the yield of biodiesel were investigated. Reusability of waste shell catalyst was also examined. The results indicated that the CaO catalysts derived from waste shell showed good reusability and had high potential to be used as biodiesel production catalysts in transesterification of palm oil with methanol. PMID:24453854

  12. Effect of Green Macroalgal Blooms on the Survival, Growth, and Behavior of Cockles in Pacific NW Estuaries

    EPA Science Inventory

    Nutrient over-enrichment of estuaries is a pervasive issue worldwide that often results in blooms of green macroalgae (GMA; Ulva spp.), which can have disruptive and deleterious effects to estuarine flora and fauna. However, little is known of the effects of GMA blooms on the pr...

  13. Silver Bells and Cockle Shells: A Study of the Conceptions of Teachers about Humane and Ethical Behavior between Colleagues.

    ERIC Educational Resources Information Center

    Grant, Rosemary

    Because the practice of humane and ethical behavior among faculty is crucial for a healthy and harmonious environment in a school, this research studied the conceptions of such behavior among a group of teachers through examination of personal narratives. The study identified situations and experiences where humane ethical behavior occurred…

  14. Calcium oxide derived from waste shells of mussel, cockle, and scallop as the heterogeneous catalyst for biodiesel production.

    PubMed

    Buasri, Achanai; Chaiyut, Nattawut; Loryuenyong, Vorrada; Worawanitchaphong, Phatsakon; Trongyong, Sarinthip

    2013-01-01

    The waste shell was utilized as a bioresource of calcium oxide (CaO) in catalyzing a transesterification to produce biodiesel (methyl ester). The economic and environmen-friendly catalysts were prepared by a calcination method at 700-1,000°C for 4 h. The heterogeneous catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) method. The effects of reaction variables such as reaction time, reaction temperature, methanol/oil molar ratio, and catalyst loading on the yield of biodiesel were investigated. Reusability of waste shell catalyst was also examined. The results indicated that the CaO catalysts derived from waste shell showed good reusability and had high potential to be used as biodiesel production catalysts in transesterification of palm oil with methanol. PMID:24453854

  15. Reproductive investment in the intertidal bivalve Macoma balthica

    NASA Astrophysics Data System (ADS)

    Honkoop, P. J. C.; Van der Meer, J.; Beukema, J. J.; Kwast, D.

    1999-05-01

    Bivalve eggs generally contain large amounts of lipids which, in comparison with proteins and carbohydrates, have high energy contents and are thus costly in energetic terms. As lipid contents vary between species, comparisons of reproductive investments should not only include numbers and sizes of eggs, but also their energy content. We estimated the investment in egg material of mature females of the Baltic tellin Macoma balthica (L.) in terms of both mass and energy content. All mass below a minimum body mass (below which no eggs are produced) was defined as structural mass. This threshold amounts to a body mass index (BMI) of 5.6 (ash-free dry mass per cubic shell length in mg cm -3). More than half (55%) of the mass above the structural mass was invested in egg material and 45% in extra somatic tissue and tissue for production and storage of gametes. This means that the amount of eggs spawned ranged from 0 (at BMI = 5.6 mg cm -3) to 33% of the total ash-free dry mass (at a high BMI value of 14 mg cm -3). Eggs contained a relatively large amount of lipids, about 30% of their ash-free dry mass, whereas non-egg material contained only about 7% lipids. Eggs of two other bivalves in the Wadden Sea, the cockle Cerastoderma edule and the mussel Mytilus edulis, were smaller and contained only about 11% and 20% lipids, respectively. Energy content of M. balthica eggs amounted to ˜0.006 J, in the other two species to ˜0.002 J. The function of the more expensive eggs in M. balthica may be related to its early spawning in spring, causing slower larval development until first feeding.

  16. Seasonal dynamics of trophic relationships among co-occurring suspension-feeders in two shellfish culture dominated ecosystems

    NASA Astrophysics Data System (ADS)

    Lefebvre, Sébastien; Marín Leal, Julio César; Dubois, Stanislas; Orvain, Francis; Blin, Jean-Louis; Bataillé, Marie-Paule; Ourry, Alain; Galois, Robert

    2009-04-01

    The temporal dynamics of carbon and nitrogen isotope values of co-occurring suspension-feeders in two shellfish culture areas (Normandy, France) were investigated over two years to evaluate the inter-specific trophic partitioning and relative contributions of organic matter sources to benthic suspension-feeders' diet. Oysters ( Crassostrea gigas), mussels ( Mytilus edulis), cockles ( Cerastoderma edule), slipper limpets ( Crepidula fornicata), and sand-mason worms ( Lanice conchilega) were sampled in an estuarine environment (Baie des Veys, east Cotentin, Normandy), while oysters, mussels, slipper limpets, and honeycomb worms ( Sabellaria alveolata) were sampled in an open-marine environment (Lingreville-sur-mer, west Cotentin, Normandy). Whatever the sampling period, the bivalves, C. gigas and M. edulis, exhibited the lowest values of δ13C and δ15N compared with the other species. Feeding relationships among suspension-feeders in both C. gigas culture areas exhibited temporal variations due to the marine/estuarine influence and seasonal changes in food supply. In the open-marine ecosystem, the contribution of phytoplankton remained the most important for all species except S. alveolata, while in the estuarine ecosystem, microphytobenthos and/or macroalgae detritus contributed a larger extent to the organisms' diets. During phytoplankton bloom periods (e.g. May and July) suspension-feeders, except for S. alveolata, relied strongly on phytoplankton; however, the majority of suspension-feeders exhibited different opportunistic behaviour in winter when phytoplankton biomass might be a limiting factor. We hypothesized that differences in particle capture and selection by the suspension-feeders influenced their isotopic values. Feeding ecology of suspension-feeders partly explained why competition was limited and why ecosystems can often support unexpectedly large numbers of suspension-feeders. We also showed that understanding ecosystem characteristics of the organic

  17. Influence of intertidal recreational fisheries and 'bouchot' mussel culture on bivalve recruitment.

    PubMed

    Toupoint, Nicolas; Barbier, Pierrick; Tremblay, Réjean; Archambault, Philippe; McKindsey, Christopher W; Winkler, Gesche; Meziane, Tarik; Olivier, Frédéric

    2016-06-01

    In coastal environments, fishing and aquaculture may be important sources of disturbance to ecosystem functioning, the quantification of which must be assessed to make them more sustainable. In the Chausey Archipelago, France, recreational fishing and commercial shellfish farming are the only two evident anthropogenic activities, dominated by bivalve hand-raking and 'bouchot' mussel culture, respectively. This study evaluates the impact of both activities on bivalve recruitment dynamics by comparing primary recruitment intensity (short-term effect) and recruitment efficiency (medium-term effect) by sampling bivalves in reference (undisturbed) and disturbed (i.e. subjected to hand-raking or in 'bouchot' mussel culture areas) parcels throughout and at the end of the recruitment season, respectively. Specific hypotheses evaluated were that (H1) bivalve hand-raking negatively affects bivalve recruitment and that (H2) 'bouchot' mussel culture promotes bivalve recruitment. Patterns in bivalve community structure in reference parcels (i.e. natural pattern) differed between initial and final recruitment, underlining the great importance of early post-settlement processes, particularly secondary dispersal. Primary recruitment intensity was inhibited in hand-raking parcels whereas it was promoted in 'bouchot' mussel culture parcels, but the effect on recruitment efficiency was muted for both activities due to post-settlement processes. Nevertheless, the importance of effects that occur during the first step of recruitment should not be ignored as they may affect bivalve communities and induce immediate consequences on the trophic web through a cascade effect. Finally, it is highlighted that hand-raking damages all life stages of the common cockle Cerastoderma edule, one of the major target species, suggesting that this activity should be managed with greater caution than is currently done. PMID:27039134

  18. Impact of trematode parasitism on the fauna of a North Sea tidal flat

    NASA Astrophysics Data System (ADS)

    Lauckner, G.

    1984-03-01

    disturbances. A single metacercaria is sufficient to kill a larval fish. Mytilus edulis and Cardium (Cerastoderma) edule are 100% infested with metacercariae of H. elongata. Heavy infestation impairs the byssus-thread production in mussels and affects the burrowing ability of cockles. Longevity and resistance to environmental — particularly thermal — stress are reduced in bivalves infested with H. elongata and R. roscovita. There is evidence that, in the study area, population size and age composition of the molluscs discussed are (indirectly) controlled by trematode parasites employing sea birds as final hosts, rather than directly by the predatory activities of these birds.

  19. Matrix solid-phase dispersion combined with gas chromatography-mass spectrometry for the determination of fifteen halogenated flame retardants in mollusks.

    PubMed

    Villaverde-de-Sáa, Eugenia; Valls-Cantenys, Carme; Quintana, José Benito; Rodil, Rosario; Cela, Rafael

    2013-07-26

    in different kind of freeze-dried mollusks: mussel (Mytilus galloprovincialis), cockle (Cerastoderma edule) and clam (R. philippinarum). Raft cultured mussels showed the highest concentrations of HFRs (up to 0.8ngg(-1) wet weight of BDE-209). PMID:23809805

  20. Ribosome-inactivating proteins from the seeds of Saponaria officinalis L. (soapwort), of Agrostemma githago L. (corn cockle) and of Asparagus officinalis L. (asparagus), and from the latex of Hura crepitans L. (sandbox tree).

    PubMed

    Stirpe, F; Gasperi-Campani, A; Barbieri, L; Falasca, A; Abbondanza, A; Stevens, W A

    1983-12-15

    Ribosome-inactivating proteins, similar to those already known [Barbieri & Stirpe (1982) Cancer Surveys 1, 489-520] were purified from the seeds of Saponaria officinalis (two proteins), of Agrostemma githago (three proteins), and of Asparagus officinalis (three proteins), and from the latex of Hura crepitans (one protein). The yield ranged from 8 to 400 mg/100 g of starting material. All proteins have an Mr of approx. 30000 and an alkaline isoelectric point. Their sugar content varies from 0 (proteins from S. officinalis) to 40% (protein from H. crepitans). The ribosome-inactivating proteins inhibit protein synthesis by rabbit reticulocyte lysate, the ID50 (concentration giving 50% inhibition) ranging from 1 ng/ml (a protein from S. officinalis) to 18 ng/ml (a protein from A. githago). Those which were tested (the proteins from S. officinalis and from A. githago) also inhibit polymerization of phenylalanine by isolated ribosomes, acting in an apparently catalytic manner. The protein from H. crepitans inhibited protein synthesis by HeLa cells, with an ID50 of 4 micrograms/ml, whereas the proteins from S. officinalis and from A. githago had an ID50 of more than 50-100 micrograms/ml. The ribosome-inactivating proteins from S. officinalis and from A. githago reduced the number of local lesions by tobacco-mosaic virus in the leaves of Nicotiana glutinosa. PMID:6667259

  1. Ribosome-inactivating proteins from the seeds of Saponaria officinalis L. (soapwort), of Agrostemma githago L. (corn cockle) and of Asparagus officinalis L. (asparagus), and from the latex of Hura crepitans L. (sandbox tree).

    PubMed Central

    Stirpe, F; Gasperi-Campani, A; Barbieri, L; Falasca, A; Abbondanza, A; Stevens, W A

    1983-01-01

    Ribosome-inactivating proteins, similar to those already known [Barbieri & Stirpe (1982) Cancer Surveys 1, 489-520] were purified from the seeds of Saponaria officinalis (two proteins), of Agrostemma githago (three proteins), and of Asparagus officinalis (three proteins), and from the latex of Hura crepitans (one protein). The yield ranged from 8 to 400 mg/100 g of starting material. All proteins have an Mr of approx. 30000 and an alkaline isoelectric point. Their sugar content varies from 0 (proteins from S. officinalis) to 40% (protein from H. crepitans). The ribosome-inactivating proteins inhibit protein synthesis by rabbit reticulocyte lysate, the ID50 (concentration giving 50% inhibition) ranging from 1 ng/ml (a protein from S. officinalis) to 18 ng/ml (a protein from A. githago). Those which were tested (the proteins from S. officinalis and from A. githago) also inhibit polymerization of phenylalanine by isolated ribosomes, acting in an apparently catalytic manner. The protein from H. crepitans inhibited protein synthesis by HeLa cells, with an ID50 of 4 micrograms/ml, whereas the proteins from S. officinalis and from A. githago had an ID50 of more than 50-100 micrograms/ml. The ribosome-inactivating proteins from S. officinalis and from A. githago reduced the number of local lesions by tobacco-mosaic virus in the leaves of Nicotiana glutinosa. Images Fig. 2. PMID:6667259

  2. Enteric virus and vibrio contamination of shellfish: intervention strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    INTRODUCTION. Molluscan shellfish include oysters, clams, mussels, and cockles, which can cause illnesses from a variety of human pathogens. Enteric viruses, like norovirus and hepatitis A virus, are generally transmitted to shellfish through fecal contamination of shellfish harvesting areas, alth...

  3. Accumulation of Trace Metals in Anadara granosa and Anadara inaequivalvis from Pattani Bay and the Setiu Wetlands.

    PubMed

    Pradit, Siriporn; Shazili, Noor Azhar Mohamed; Towatana, Prawit; Saengmanee, Wuttipong

    2016-04-01

    This study was undertaken to assess the levels of trace metals (As, Cd, Cu, Pb, and Zn) in two common species of cockles (Anadara granosa and Anadara inaequivalvis) from two coastal areas in Thailand (Pattani Bay) and Malaysia (the Setiu Wetlands). A total of 350 cockles were collected in February and September 2014. Trace metals were determined by Inductively Coupled Plasma Mass Spectrometry. We observed that cockles in both areas had a higher accumulation of metals in September. Notably, the biota-sediment accumulation (BSAF) of Cd was highest in both areas. A strong positive correlation of Cd with the length of the cockles at Pattani Bay (r(2) = 0.597) and the Setiu Wetlands (r(2) = 0.675) was noted. It was suggested that As could be a limiting element (BSAF < 1) of cockles obtained from Pattani Bay. In comparison with the permissible limits set by the Thailand Ministry of Public Health and the Malaysia Food Regulations, mean values of As, Cd, Cu, Pb, and Zn were within acceptable limits, but the maximum values of Cd and Pb exceeded the limits for both areas. Regular monitoring of trace metals in cockles from both areas is suggested for more definitive contamination determination. PMID:26725081

  4. The influence of four macrozoobenthic species on the abundance of the amphipod Corophium volutator on tidal flats of the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Flach, E. C.

    On the tidal flats of the Wadden Sea, a zonation pattern can be found with Corophium volutator and Nereis diversicolor as the dominating species of the upper intertidal zone and Arenicola marina and Cerastoderma edule as the dominating species of the lower zone. As C. volutator can live under a great variety of physical conditions, its restriction to higher areas might result from biotic interactions. This was investigated by field experiments on a tidal flat in the westernmost part of the Wadden Sea. Within large depopulated areas, small plots were recolonized with different densities of N. diversicolor, A. marina, C. edule and Macoma balthica and the subsequent settlement and dynamics of C. volutator were studied. In addition, A. marina and/or C. edule were added to or removed from small plots within a natural benthic community. Neither the presence of M. balthica not that of N. diversicolor significantly affected the abundance of C. volutator. A strongly negative effect was found of C. edule when present in high densities, whereas A. marina negatively affected C. volutator abundance already at relatively low densities. Local removals of A. marina and C. edule from their own zone resulted in increases of Corophium numbers at these locations and local additions of these species within the Corophium zone resulted in decreases of Corophium numbers at these locations. It is suggested that the major species to restrict C. volutator effectively to the upper tidal zone is A. marina.

  5. Differential reproductive strategies of two bivalves in the Dutch Wadden Sea

    NASA Astrophysics Data System (ADS)

    Cardoso, Joana F. M. F.; Witte, Johannes IJ.; van der Veer, Henk W.

    2009-08-01

    Cerastoderma edule and Mya arenaria are two common bivalve species in European waters. Longevity and maximum size are much greater in the latter species. Because comparison of species life-history strategies states that a long life span (i.e. high annual survival) generally goes with lower fecundity, we hypothesise that reproductive output would be lower in M. arenaria than in C. edule. In the present paper, we studied the reproductive strategies of these two species in an intertidal and a subtidal area of the western Dutch Wadden Sea, by following seasonal changes in absolute and relative weights of somatic and gonadal tissues in these bivalves. Starting of spawning was similar in the two species, around May, except for intertidal M. arenaria, which initiated spawning in August. Individual energy investment in reproduction was similar for the two species but, unlike M. arenaria, C. edule spawned completely, releasing all energy of gonadal mass in the form of gametes. Mya arenaria used the gonad not only for reproduction but also for storage. In the intertidal area, we found a trade-off between longevity and reproduction, i.e. maximum reproductive output (expressed as a proportion of body mass) was higher in C. edule than in M. arenaria. However, since body size is larger and life span longer in M. arenaria than in C. edule, mean lifetime reproductive output per individual must be higher in the first than in the latter. Based on the differences in reproductive strategies of these two species, we hypothesise that the negative effects of warming climate on bivalve population dynamics in the Wadden Sea will be stronger in C. edule than in M. arenaria.

  6. Food supply and dispersal in the determination of wintering population levels of oystercatchers, Haematopus ostralegus

    NASA Astrophysics Data System (ADS)

    Sutherland, William J.

    1982-02-01

    A considerable cockle spatfall in 1975 led to a dramatic, short-lived increasein the cockle population on the Ribble Estuary. There was a parallel fluctuation in the numbers of oystercatchers. The correlation between the two was high. This study contrasts with that on the Burry Inlet where the numbers ofoystercatchers did not vary greatly with the number of cockles. It appears that dispersal is an important factor determining the number of birds on the Ribble, yet other population processes appear to affect the Burry Inlet oystercatchers. Much of the increase in the oystercatcher numbers on the Ribble was due to the immigration of young birds. It appears that young birds seek a suitable estuary whilst adults tend to return to the one found whilst young.

  7. The coquaternion algebra and complex partial differential equations

    NASA Astrophysics Data System (ADS)

    Dimiev, Stancho; Konstantinov, Mihail; Todorov, Vladimir

    2009-11-01

    In this paper we consider the problem of differentiation of coquaternionic functions. Let us recall that coquaternions are elements of an associative non-commutative real algebra with zero divisor, introduced by James Cockle (1849) under the name of split-quaternions or coquaternions. Developing two type complex representations for Cockle algebra (complex and paracomplex ones) we present the problem in a non-commutative form of the δ¯-type holomorphy. We prove that corresponding differentiable coquaternionic functions, smooth and analytic, satisfy PDE of complex, and respectively of real variables. Applications for coquaternionic polynomials are sketched.

  8. Interspecific variability of antioxidant activities and phenolic composition in Mesembryanthemum genus.

    PubMed

    Hanen, Falleh; Riadh, Ksouri; Samia, Oueslati; Sylvain, Guyot; Christian, Magné; Chedly, Abdelly

    2009-09-01

    In the present study, shoot extracts from edible halophytic Mesembryanthemum species were evaluated for their effects against O(2)(-), DPPH, and ABTS radicals. The reducing power, chelating ability, inhibition of lipid peroxidation and of beta-carotene bleaching were also evaluated. Moreover, the total phenolic, flavonoid, and condensed tannin contents were determined. In vitro biotests showed a significant difference in the antioxidant capacities of the species studied. Mesembryanthemum edule was found to exhibit the higher antioxidant activity, except for the iron-chelating test where M. crystallinum showed the best activity with the lowest EC(50) value (2.13 mg ml(-1)). Accordingly, M. edule exhibited high phenolic levels, especially in total phenols (70mg of gallic acid equivalents/g dry weight), while no significant difference was found between M. crystallinum and M. nodiflorum (1.4 and 1.7 mg GAE g(-1)DW, respectively). Due to its strong antioxidant activities and high levels of phenols, M. edule was further studied for its phenolic constituents. HPLC analysis revealed 12 compounds, mainly flavonoids, with phloretin, quercitrin, and avicularin as the most abundant (1, 0.84 and 0.66 mg g(-1) DW, respectively). These results evidenced the great variability in antioxidant capacities of these halophytes and suggested that M. edule might be an important source of functional phenolic compounds. PMID:19540899

  9. Concentrations of total and inorganic arsenic in fresh fish, mollusks, and crustaceans from the Gulf of Thailand.

    PubMed

    Ruangwises, Suthep; Ruangwises, Nongluck

    2011-03-01

    Concentrations of total and inorganic arsenic were determined in 120 samples of eight marine animals collected from the Gulf of Thailand between March and May 2008. Two species with the highest annual catch from each of four marine animal groups were analyzed: fish (Indo-Pacific mackerel and goldstripe sardine), bivalves (green mussel and blood cockle), cephalopods (pharaoh cuttlefish and Indian squid), and crustaceans (banana prawn and swimming crab). Concentrations of inorganic arsenic based on wet weight ranged from 0.012 μg/g in Indian squids to 0.603 μg/g in blood cockles. Average percentages of inorganic arsenic with respect to total arsenic ranged from 1.2% in banana prawns to 7.3% in blood cockles. Blood cockles also exhibited the highest levels of total arsenic (5.26 ± 2.01 μg/g) and inorganic arsenic (0.352 ± 0.148 μg/g). The levels of inorganic arsenic in the study samples were much lower than the Thai regulatory limit of 2 μg/g (wet wt) and hence are safe for human consumption. PMID:21375883

  10. Metalexical Awareness: Development, Methodology or Written Language? A Cross-Linguistic Comparison

    ERIC Educational Resources Information Center

    Kurvers, Jeanne; Uri, Helene

    2006-01-01

    This study explores the ability to access word boundaries of pre-school children, using an on-line methodology (Karmiloff-Smith, Grant, Sims, Jones, & Cockle (1996). "Cognition, 58", 197-219.), which has hardly been used outside English-speaking countries. In a cross-linguistic study in the Netherlands and Norway, four and five-year-old children…

  11. Reconstruction of food conditions for Northeast Atlantic bivalve species based on Dynamic Energy Budgets

    NASA Astrophysics Data System (ADS)

    Freitas, Vânia; Cardoso, Joana F. M. F.; Santos, Sílvia; Campos, Joana; Drent, Jan; Saraiva, Sofia; Witte, Johannes IJ.; Kooijman, Sebastiaan A. L. M.; Van der Veer, Henk W.

    2009-08-01

    Required assimilated energy to support observed growth was reconstructed for four common bivalve species ( Mya arenaria, Cerastoderma edule, Mytilus edulis and Macoma balthica) from various Northeast Atlantic coastal areas, along the species distributional range. The approach applied was based on the Dynamic Energy Budget (DEB) theory whereby observed growth patterns in the field, in combination with prevailing temperatures, were used to reconstruct the average food intake experienced in the field scaled to the maximum possible. For all species, results suggest food limitation over the range of locations. In general, reconstructed food intake indicated better conditions for C. edule compared to the other species, while M. edulis presented the lowest food conditions in all the areas. Despite the indications for a latitudinal trend in primary production, no clear pattern or relationship between reconstructed food conditions and latitude was observed suggesting that any trend may be overruled by local conditions.

  12. Simulated leakage of high pCO2 water negatively impacts bivalve dominated infaunal communities from the Western Baltic Sea.

    PubMed

    Schade, Hanna; Mevenkamp, Lisa; Guilini, Katja; Meyer, Stefanie; Gorb, Stanislav N; Abele, Doris; Vanreusel, Ann; Melzner, Frank

    2016-01-01

    Carbon capture and storage is promoted as a mitigation method counteracting the increase of atmospheric CO2 levels. However, at this stage, environmental consequences of potential CO2 leakage from sub-seabed storage sites are still largely unknown. In a 3-month-long mesocosm experiment, this study assessed the impact of elevated pCO2 levels (1,500 to 24,400 μatm) on Cerastoderma edule dominated benthic communities from the Baltic Sea. Mortality of C. edule was significantly increased in the highest treatment (24,400 μatm) and exceeded 50%. Furthermore, mortality of small size classes (0-1 cm) was significantly increased in treatment levels ≥6,600 μatm. First signs of external shell dissolution became visible at ≥1,500 μatm, holes were observed at >6,600 μatm. C. edule body condition decreased significantly at all treatment levels (1,500-24,400 μatm). Dominant meiofauna taxa remained unaffected in abundance. Densities of calcifying meiofauna taxa (i.e. Gastropoda and Ostracoda) decreased in high CO2 treatments (>6,600 μatm), while the non - calcifying Gastrotricha significantly increased in abundance at 24,400 μatm. In addition, microbial community composition was altered at the highest pCO2 level. We conclude that strong CO2 leakage can alter benthic infauna community composition at multiple trophic levels, likely due to high mortality of the dominant macrofauna species C. edule. PMID:27538361

  13. Simulated leakage of high pCO2 water negatively impacts bivalve dominated infaunal communities from the Western Baltic Sea

    PubMed Central

    Schade, Hanna; Mevenkamp, Lisa; Guilini, Katja; Meyer, Stefanie; Gorb, Stanislav N.; Abele, Doris; Vanreusel, Ann; Melzner, Frank

    2016-01-01

    Carbon capture and storage is promoted as a mitigation method counteracting the increase of atmospheric CO2 levels. However, at this stage, environmental consequences of potential CO2 leakage from sub-seabed storage sites are still largely unknown. In a 3-month-long mesocosm experiment, this study assessed the impact of elevated pCO2 levels (1,500 to 24,400 μatm) on Cerastoderma edule dominated benthic communities from the Baltic Sea. Mortality of C. edule was significantly increased in the highest treatment (24,400 μatm) and exceeded 50%. Furthermore, mortality of small size classes (0–1 cm) was significantly increased in treatment levels ≥6,600 μatm. First signs of external shell dissolution became visible at ≥1,500 μatm, holes were observed at >6,600 μatm. C. edule body condition decreased significantly at all treatment levels (1,500–24,400 μatm). Dominant meiofauna taxa remained unaffected in abundance. Densities of calcifying meiofauna taxa (i.e. Gastropoda and Ostracoda) decreased in high CO2 treatments (>6,600 μatm), while the non - calcifying Gastrotricha significantly increased in abundance at 24,400 μatm. In addition, microbial community composition was altered at the highest pCO2 level. We conclude that strong CO2 leakage can alter benthic infauna community composition at multiple trophic levels, likely due to high mortality of the dominant macrofauna species C. edule. PMID:27538361

  14. Recent innovation in microbial source tracking using bacterial real-time PCR markers in shellfish.

    PubMed

    Mauffret, A; Mieszkin, S; Morizur, M; Alfiansah, Y; Lozach, S; Gourmelon, M

    2013-03-15

    We assessed the capacity of real-time PCR markers to identify the origin of contamination in shellfish. Oyster, cockles or clams were either contaminated with fecal materials and host-associated markers designed from Bacteroidales or Catellicoccus marimammalium 16S RNA genes were extracted from their intravalvular liquid, digestive tissues or shellfish flesh. Extraction of bacterial DNA from the oyster intravalvular liquid with FastDNA spin kit for soil enabled the selected markers to be quantified in 100% of artificially contaminated samples, and the source of contamination to be identified in 13 out of 38 naturally contaminated batches from European Class B and Class C areas. However, this protocol did not enable the origin of the contamination to be identified in cockle or clam samples. Although results are promising for extracts from intravalvular liquid in oyster, it is unlikely that a single protocol could be the best across all bacterial markers and types of shellfish. PMID:23398745

  15. Transcriptome-derived microsatellite markers for Dioon (Zamiaceae) cycad species1

    PubMed Central

    Prado, Alberto; Cervantes-Díaz, Fret; Perez-Zavala, Francisco G.; González-Astorga, Jorge; Bede, Jacqueline C.; Cibrián-Jaramillo, Angélica

    2016-01-01

    Premise of the study: Dioon (Zamiaceae) is an endangered North American cycad genus of evolutionary and ornamental value. We designed and validated a set of microsatellite markers from D. edule that can be used for population-level and conservation studies, and that transferred successfully to D. angustifolium, D. spinulosum, and D. holmgrenii. Methods and Results: We tested 50 primers from 80 microsatellite candidate loci in the OneKP D. edule transcriptome. Genotypes from 21 loci in 20 D. edule individuals revealed up to 14 alleles per locus and observed heterozygosity from 0.15 to 0.92; one locus was monomorphic. Seven of those 21 loci were polymorphic in D. angustifolium, D. spinulosum, and D. holmgrenii, with up to seven alleles, and an observed heterozygosity up to 0.89. Conclusions: The transcriptome-derived microsatellites generated here will serve as tools to advance population genetic studies and inform conservation strategies of Dioon, including the identification and origin of illegal plants in the cycad trade. PMID:26949574

  16. The Anadara trapezia transcriptome: a resource for molluscan physiological genomics.

    PubMed

    Prentis, Peter J; Pavasovic, Ana

    2014-12-01

    In this study we undertook deep sequencing of the blood cockle, Anadara trapezia, transcriptome to generate genomic resources for future functional genomics analyses. Over 27 million high quality paired end reads were assembled into 75024 contigs. Of these contigs, 29013 (38.7%) received significant BLASTx hits and gene ontology (GO) terms were assigned to 13718 of these sequences. This resource will facilitate physiological genomic studies to test the gene expression response of A. trapezia to various environmental stresses. PMID:25151889

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

    PubMed

    Dang, Cécile; Dungan, Christopher F; Scott, Gail P; Reece, Kimberly S

    2015-02-10

    Perkinsus sp. protists were found infecting Anadara trapezia mud ark cockles at 6 sites in Moreton Bay, Queensland, Australia, at prevalences of 4 to 100% during 2011 as determined by surveys using Ray's fluid thioglycollate medium. Perkinsus sp. lesions were found among gill and visceral connective tissues in histological samples from several cockles, where basophilic, eccentrically vacuolated Perkinsus sp. signet ring trophozoites and proliferating, Perkinsus sp. schizont cells were documented. Two Perkinsus sp. isolates were propagated in vitro during August 2013 from gill tissues of a single infected A. trapezia cockle from Wynnum in Moreton Bay. DNA from those isolate cells amplified universally by a Perkinsus genus-specific PCR assay, and rDNA-internal transcribed spacer sequences respectively grouped them with P. olseni and P. chesapeaki in phylogenetic analyses. This is the first report of P. chesapeaki in Australia, and the first report of a P. chesapeaki in vitro isolate from an Australian mollusc host. Although P. olseni was originally described in 1981 as a pathogen of abalone in South Australia, and has subsequently been identified as a prevalent pathogen of numerous other molluscs worldwide, this is also the first report of a P. olseni-like in vitro isolate from an Australian mollusc host. PMID:25667336

  18. The effects of the adult density of Macoma balthica on the recruitment of juvenile bivalves: a field experiment

    NASA Astrophysics Data System (ADS)

    Richards, M.; Edwards, F.; Huxham, M.

    2002-02-01

    Populations of intertidal bivalves are patchily distributed at a variety of scales, and the distributions of adults and juveniles are often different. Adult-juvenile interactions may help explain this patchiness. In this study, the effects of different densities of adult Macoma balthica (L.) on the numbers of re-locating juvenile M. balthica and Cerastoderma edule (L.) were examined. Two field experiments were conducted, which established three densities of adult M. balthica (reflecting the range of values found on the study site) and allowed recruitment of bivalves into experimental plots for two tidal cycles. Both experiments were run at peak summer arrival of juveniles at this site. The first was open to predators, the second was protected from larger epibenthic and avian predators by cages. The mean number of juvenile C. edule found in the high-density treatment was significantly lower than in the other density treatments in the first (open) experiment. There was also evidence of density-dependent predation by Carcinus maenas (L.). There were no significant effects of adult M. balthica density on the numbers of juvenile bivalves in the caged experiment. These results were compared with those from a small-scale field survey, which showed a negative correlation between juvenile M. balthica ≤1.6 mm and individuals ≥1.6 mm. Our study suggests that densities of M. balthica ≥1.6 mm may have an impact on the numbers of juvenile bivalves (in particular, C. edule) re-locating at this site, but that this effect is not the result of direct adult-juvenile interactions, but is caused indirectly by density-dependent predation by C. maenas.

  19. Maritime halophyte species from southern Portugal as sources of bioactive molecules.

    PubMed

    Rodrigues, Maria João; Gangadhar, Katkam N; Vizetto-Duarte, Catarina; Wubshet, Sileshi G; Nyberg, Nils T; Barreira, Luísa; Varela, João; Custódio, Luísa

    2014-04-01

    Extracts of five halophytes from southern Portugal (Arthrocnemum macrostachyum, Mesembryanthemum edule, Juncus acutus, Plantago coronopus and Halimione portulacoides), were studied for antioxidant, anti-inflammatory and in vitro antitumor properties. The most active extracts towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were the methanol extracts of M. edule (IC₅₀ = 0.1 mg/mL) and J. acutus (IC₅₀ = 0.4 mg/mL), and the ether extracts of J. acutus (IC₅₀ = 0.2 mg/mL) and A. macrostachyum (IC₅₀ = 0.3 mg/mL). The highest radical scavenging activity (RSA) against the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical was obtained in the ether extract of J. acutus (IC₅₀ = 0.4 mg/mL) and H. portulacoides (IC₅₀ = 0.9 mg/mL). The maximum total phenolic content (TPC) was found in the methanol extract of M. edule (147 mg gallic acid equivalents (GAE)/g) and in the ether extract of J. acutus (94 mg GAE/g). Significant decreases in nitric oxide (NO) production were observed after incubation of macrophages with lipopolysaccharide (LPS) and the chloroform extract of H. portulacoides (IC₅₀ = 109 µg/mL) and the hexane extract of P. coronopus (IC₅₀ = 98.0 µg/mL). High in vitro cytotoxic activity and selectivity was obtained with the ether extract of J. acutus. Juncunol was identified as the active compound and for the first time was shown to display selective in vitro cytotoxicity towards various human cancer cells. PMID:24727393

  20. Maritime Halophyte Species from Southern Portugal as Sources of Bioactive Molecules

    PubMed Central

    Rodrigues, Maria João; Gangadhar, Katkam N.; Vizetto-Duarte, Catarina; Wubshet, Sileshi G.; Nyberg, Nils T.; Barreira, Luísa; Varela, João; Custódio, Luísa

    2014-01-01

    Extracts of five halophytes from southern Portugal (Arthrocnemum macrostachyum, Mesembryanthemum edule, Juncus acutus, Plantago coronopus and Halimione portulacoides), were studied for antioxidant, anti-inflammatory and in vitro antitumor properties. The most active extracts towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were the methanol extracts of M. edule (IC50 = 0.1 mg/mL) and J. acutus (IC50 = 0.4 mg/mL), and the ether extracts of J. acutus (IC50 = 0.2 mg/mL) and A. macrostachyum (IC50 = 0.3 mg/mL). The highest radical scavenging activity (RSA) against the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical was obtained in the ether extract of J. acutus (IC50 = 0.4 mg/mL) and H. portulacoides (IC50 = 0.9 mg/mL). The maximum total phenolic content (TPC) was found in the methanol extract of M. edule (147 mg gallic acid equivalents (GAE)/g) and in the ether extract of J. acutus (94 mg GAE/g). Significant decreases in nitric oxide (NO) production were observed after incubation of macrophages with lipopolysaccharide (LPS) and the chloroform extract of H. portulacoides (IC50 = 109 µg/mL) and the hexane extract of P. coronopus (IC50 = 98.0 µg/mL). High in vitro cytotoxic activity and selectivity was obtained with the ether extract of J. acutus. Juncunol was identified as the active compound and for the first time was shown to display selective in vitro cytotoxicity towards various human cancer cells. PMID:24727393

  1. Interactions between Seagrass Complexity, Hydrodynamic Flow and Biomixing Alter Food Availability for Associated Filter-Feeding Organisms

    PubMed Central

    González-Ortiz, Vanessa; Egea, Luis G.; Jiménez-Ramos, Rocio; Moreno-Marín, Francisco; Pérez-Lloréns, José L.; Bouma, Tjeed J.; Brun, Fernando G.

    2014-01-01

    Seagrass shoots interact with hydrodynamic forces and thereby a positively or negatively influence the survival of associated species. The modification of these forces indirectly alters the physical transport and flux of edible particles within seagrass meadows, which will influence the growth and survivorship of associated filter-feeding organisms. The present work contributes to gaining insight into the mechanisms controlling the availability of resources for filter feeders inhabiting seagrass canopies, both from physical (influenced by seagrass density and patchiness) and biological (regulated by filter feeder density) perspectives. A factorial experiment was conducted in a large racetrack flume, which combined changes in hydrodynamic conditions, chlorophyll a concentration in the water and food intake rate (FIR) in a model active filter-feeding organism (the cockle). Results showed that seagrass density and patchiness modified both hydrodynamic forces and availability of resources for filter feeders. Chlorophyll a water content decreased to 50% of the initial value when densities of both seagrass shoots and cockles were high. Also, filter feeder density controlled resource availability within seagrass patches, depending on its spatial position within the racetrack flume. Under high density of filter-feeding organisms, chlorophyll a levels were lower between patches. This suggests that the pumping activity of cockles (i.e. biomixing) is an emergent key factor affecting both resource availability and FIR for filter feeders in dense canopies. Applying our results to natural conditions, we suggest the existence of a direct correlation between habitat complexity (i.e. shoot density and degree of patchiness) and filter feeders density. Fragmented and low-density patches seem to offer both greater protection from hydrodynamic forces and higher resource availability. In denser patches, however, resources are allocated mostly within the canopy, which would benefit

  2. Interactions between seagrass complexity, hydrodynamic flow and biomixing alter food availability for associated filter-feeding organisms.

    PubMed

    González-Ortiz, Vanessa; Egea, Luis G; Jiménez-Ramos, Rocio; Moreno-Marín, Francisco; Pérez-Lloréns, José L; Bouma, Tjeed J; Brun, Fernando G

    2014-01-01

    Seagrass shoots interact with hydrodynamic forces and thereby a positively or negatively influence the survival of associated species. The modification of these forces indirectly alters the physical transport and flux of edible particles within seagrass meadows, which will influence the growth and survivorship of associated filter-feeding organisms. The present work contributes to gaining insight into the mechanisms controlling the availability of resources for filter feeders inhabiting seagrass canopies, both from physical (influenced by seagrass density and patchiness) and biological (regulated by filter feeder density) perspectives. A factorial experiment was conducted in a large racetrack flume, which combined changes in hydrodynamic conditions, chlorophyll a concentration in the water and food intake rate (FIR) in a model active filter-feeding organism (the cockle). Results showed that seagrass density and patchiness modified both hydrodynamic forces and availability of resources for filter feeders. Chlorophyll a water content decreased to 50% of the initial value when densities of both seagrass shoots and cockles were high. Also, filter feeder density controlled resource availability within seagrass patches, depending on its spatial position within the racetrack flume. Under high density of filter-feeding organisms, chlorophyll a levels were lower between patches. This suggests that the pumping activity of cockles (i.e. biomixing) is an emergent key factor affecting both resource availability and FIR for filter feeders in dense canopies. Applying our results to natural conditions, we suggest the existence of a direct correlation between habitat complexity (i.e. shoot density and degree of patchiness) and filter feeders density. Fragmented and low-density patches seem to offer both greater protection from hydrodynamic forces and higher resource availability. In denser patches, however, resources are allocated mostly within the canopy, which would benefit

  3. Interspecific comparison of polycyclic aromatic hydrocarbons and persistent organochlorines bioaccumulation in bivalves from a Mediterranean coastal lagoon.

    PubMed

    León, Víctor M; Moreno-González, Rubén; González, Emilia; Martínez, Fulgencio; García, Víctor; Campillo, Juan A

    2013-10-01

    The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was characterized in cockle, oyster and noble pen shell from nine areas in the Mar Menor lagoon with different hydrodynamic and pollutant sources. Biota, sediment and water samples were simultaneously collected in the spring and autumn of 2010. Considering all bivalve samples, PAH concentrations ranged from 8.98 to 370 μg·kg(-1) d.w., those of PCBs from 0.15 to 42.36 μg·kg(-1) d.w. and those of DDXs from below detection limit to 240.6 μg·kg(-1) d.w., where p,p'-DDE was the main fraction. The bioaccumulation of PAHs was similar for cockle, oyster and noble pen shell, being higher close to ports and wastewater effluents. However, DDX and PCB bioaccumulations in oyster and noble pen shell were significantly higher than in cockle in spring (p=0.02). The first organic pollutant bioaccumulation data for noble pen shell were obtained in this study, showing a preferential accumulation of pyrene. The increase of PAH bioaccumulation in autumn, as compared to spring, was low, due to high water temperatures during the summer, which favoured PAH dissipation processes. No significant seasonal variations were detected for OCPs and PCBs, except in some specific areas. The PAH, PCB and OCP levels detected in these bivalves were lower than OSPAR/MED POL environmental assessment criteria, except for p,p'-DDE in bivalves sited close to El Albujón watercourse mouth. PMID:23872249

  4. Interspecific variation of metal concentrations in three bivalve mollusks from Galicia.

    PubMed

    Saavedra, Y; González, A; Fernández, P; Blanco, J

    2004-10-01

    There has been growing concern about the inflow of metals to the coastal areas because they can be toxic to aquatic and human life. Some studies have demonstrated the existence of species-specific differences in the metal concentrations of mollusks. We compared metal concentrations between Mytilus galloprovincialis, used as a water quality indicator, and two other bivalve species collected for human consumption (Venerupis pullastra and Cerastoderma edule) in different locations on the Galician coast (northwest Spain). M. galloprovincialis was found to be the best zinc and lead accumulator, whereas silver and arsenic were preferentially accumulated by V. pullastra and chromium and nickel by C. edule. Bivalve concentrations of mercury, cadmium, chromium, arsenic, silver, and zinc appeared to be linearly related to environmental concentrations, but this was not the case with copper, nickel, and lead in some species, which indicated that there is a nonlinear accumulation of these metals or an influence of the environmental conditions on species accumulation. The relationship between metal concentration in mussels and in the two other species varied with the metal and the species. In some cases the correlation was high, making it possible to use mussels as bioindicators for the other species. In other cases the correlation was moderate or low, therefore rendering mussels of little or no use in predicting the metal concentrations in the two other species. PMID:15386128

  5. Larviphagy in native bivalves and an introduced oyster

    NASA Astrophysics Data System (ADS)

    Troost, Karin; Kamermans, Pauline; Wolff, Wim J.

    2008-10-01

    Introduced Pacific oysters Crassostrea gigas have expanded rapidly in the Dutch Oosterschelde estuary, while stocks of native bivalves declined slightly. As a consequence, total filtration pressure increased significantly, which may affect the mortality of bivalve larvae. Better escape abilities in Pacific oyster larvae might be a contributing factor to their rapid geographic expansion. To study whether C. gigas larvae are filtered less than larvae of native bivalves, we investigated filtration and ingestion of the larvae of the native Mytilus edulis and introduced C. gigas by the adults of C. gigas and M. edulis as well as the native Cerastoderma edule. We measured filtration rates of C. gigas and M. edulis larvae by the adult bivalves ( C. gigas, M. edulis and C. edule), and compared these to filtration rates of algae. Additionally, we studied the fate of filtered larvae. All three adult species filtered both C. gigas and M. edulis larvae. M. edulis larvae were filtered by all three bivalve species with the same filtration rates as algae, whereas filtration rates of C. gigas larvae were roughly 50% lower than filtration rates of algae. This suggests that C. gigas larvae can somehow reduce their filtration risk, whereas larvae of M. edulis cannot. The majority of filtered C. gigas and M. edulis larvae were ingested.

  6. Occurrence of Squash yellow mild mottle virus and Pepper golden mosaic virus in Potential New Hosts in Costa Rica

    PubMed Central

    Castro, Ruth M.; Moreira, Lisela; Rojas, María R.; Gilbertson, Robert L.; Hernández, Eduardo; Mora, Floribeth; Ramírez, Pilar

    2013-01-01

    Leaf samples of Solanum lycopersicum, Capsicum annuum, Cucurbita moschata, Cucurbita pepo, Sechium edule and Erythrina spp. were collected. All samples were positive for begomoviruses using polymerase chain reaction and degenerate primers. A sequence of ∼1,100 bp was obtained from the genomic component DNA-A of 14 samples. In addition, one sequence of ∼580 bp corresponding to the coat protein (AV1) was obtained from a chayote (S. edule) leaf sample. The presence of Squash yellow mild mottle virus (SYMMoV) and Pepper golden mosaic virus (PepGMV) were confirmed. The host range reported for SYMMoV includes species of the Cucurbitaceae, Caricaceae and Fabaceae families. This report extends the host range of SYMMoV to include the Solanaceae family, and extends the host range of PepGMV to include C. moschata, C. pepo and the Fabaceae Erythrina spp. This is the first report of a begomovirus (PepGMV) infecting chayote in the Western Hemisphere. PMID:25288955

  7. Prevalence and antimicrobial susceptibilities of Vibrio, salmonella, and Aeromonas isolates from various uncooked seafoods in Thailand.

    PubMed

    Woodring, Joseph; Srijan, Apichai; Puripunyakom, Paksathorn; Oransathid, Wilawan; Wongstitwilairoong, Boonchai; Mason, Carl

    2012-01-01

    Uncooked seafood samples were collected from open markets and supermarkets in Bangkok, Thailand, and were examined for the presence of Vibrio, Salmonella, and Aeromonas species from January to February 2008. From 120 samples, 272 bacterial isolates were identified through biochemical testing. Of all sea bass, shrimp, oyster, and blood cockle samples (30 of each) that were processed for culture, 114 (95%) samples had at least one detectable isolate of Vibrio, Salmonella, or Aeromonas, leaving only 6 (5%) samples free of them. All oyster sample (100%) had at least one pathogen, followed by sea bass (97%), blood cockles (97%), and shrimp (90%). Overall, 111 (92%) of all samples had detectable Vibrio spp., 32 (27%) had detectable Aeromonas spp., and 25 (21%) had detectable Salmonella enterica. There was no overall difference between positive samples collected from fresh markets versus supermarkets (relative risk, 0.97; 95% CI, 0.89 to 1.05). Resistance to ampicillin among isolated pathogens was relatively high (56%), while resistance to 12 other antibiotics, including azithromycin, ciprofloxacin, and trimethoprim-sulfamethoxazole, was relatively low (0, 0, and 3%, respectively). Study results indicate that uncooked seafood in Bangkok, Thailand, commonly harbors enteric pathogens and that consumption of uncooked seafood should be avoided to reduce foodborne illnesses. PMID:22221354

  8. Tumor formations in scleractinian corals

    NASA Astrophysics Data System (ADS)

    Loya, Y.; Bull, G.; Pichon, M.

    1984-03-01

    A highly localized incidence of skeletal malformations (tumors) in the scleractinian corals Platygyra pini and P. sinensis on an inshore fringing reef at Cockle Bay, Magnetic Island within the Great Barrier Reef province is reported. These tumors are typified by a localized area of increased growth rate resulting in roughly circular protuberances extending up to 4.5 cm above the colony's surface. In both species, similar proportions of their populations carried tumors (24.1 % in P. pini and 18.7 % in P. sinensis). Larger colonies (>80 cm in diameter) are at least 7 times more likely to possess tumors than smaller colonies (<40 cm in diameter). X-radiographs of the skeletal malformations indicate a point of origin, presumably from a single budded polyp with subsequent, localized, accelerated growth. The mean radial growth rate of the tumorous area was 29 % greater than that of the surrounding normal regions. In contrast to the normal tissue, the tumorous tissue exhibited proliferation of cells, atrophied gastrodermal cells and mesenterial filaments which were larger and disordered in structure. The environmental conditions at Cockle Bay are relatively extreme with high turbidity, periodic exposure of the reef flat, abrupt changes in salinity during the wet season and mechanical damage to corals caused by unpredictable cyclonic storms. It is suggested that a combination of environmental stresses coupled with an injury inflicted on the corals are possible stimuli that initiate the development of these abnormal growth through either bacterial attack or the development of an aberrant polyp during tissue repair.

  9. Simulating pesticides in ditches to assess ecological risk (SPIDER): II. Benchmarking for the drainage model.

    PubMed

    Renaud, Fabrice G; Brown, Colin D

    2008-05-01

    SPIDER (simulating pesticides in ditches to assess ecological risk) is a locally distributed, capacitance-based model that accounts for pesticide entry into surface water bodies via spray drift, surface runoff, interlayer flow and drainage. SPIDER was developed for application to small agricultural catchments. Transport of pesticide from site of application to surface water via subsurface field drains is one of the major routes of entry to surface water. Several pesticide fate models describe transfer of pesticide via drainflow, notably MACRO which has been evaluated against field data in several studies. The capacity of SPIDER to simulate drainflow and pesticide concentration in drain water was evaluated against two datasets that had been used previously to evaluate MACRO independently of this study: a plot experiment at Cockle Park and a field experiment at Maidwell, both located in the UK. In both circumstances, SPIDER was able to reproduce drain hydrographs relatively well with no or limited calibration. At Cockle Park, simulated and observed drainflow over the season were 240 and 278 mm, respectively with a Nash and Sutcliffe model efficiency (NSME) coefficient of 0.32 whilst at Maidwell they were 259 and 296 mm, respectively with a NSME coefficient of 0.55. Prediction of maximum isoproturon concentration at Cockle Park by SPIDER and MACRO were 5.3 and 13.1 microg L(- 1) respectively compared to the 3.8 microg L(- 1) measured in the field, whilst pesticide load to drains over the season were 0.22 and 1.53 g, respectively, compared to an observed load of 0.35 g. Maximum sulfosulfuron concentration at Maidwell were 2.3, 3.9 and 5.4 microg L(- 1) for observed and as simulated by SPIDER and MACRO, respectively and pesticide loading to drains of the season was 0.77, 5.61, 4.77 g, respectively. Results from the sensitivity analysis showed that the sensitivity of SPIDER compared favourably to that of several other capacity models but was more sensitive than MACRO to

  10. Phylogenetic and microscopic studies in the genus Lactifluus (Basidiomycota, Russulales) in West Africa, including the description of four new species.

    PubMed

    Maba, Dao Lamèga; Guelly, Atsu K; Yorou, Nourou S; Verbeken, Annemieke; Agerer, Reinhard

    2015-06-01

    Despite the crucial ecological role of lactarioid taxa (Lactifluus, Lactarius) as common ectomycorrhiza formers in tropical African seasonal forests, their current diversity is not yet adequately assessed. During the last few years, numerous lactarioid specimens have been sampled in various ecosystems from Togo (West Africa). We generated 48 ITS sequences and aligned them against lactarioid taxa from other tropical African ecozones (Guineo-Congolean evergreen forests, Zambezian miombo). A Maximum Likelihood phylogenetic tree was inferred from a dataset of 109 sequences. The phylogenetic placement of the specimens, combined with morpho-anatomical data, supported the description of four new species from Togo within the monophyletic genus Lactifluus: within subgen. Lactifluus (L. flavellus), subgen. Russulopsis (L. longibasidius and L. pectinatus), and subgen. Edules (L. melleus). This demonstrates that the current species richness of the genus is considerably higher than hitherto estimated for African species and, in addition, a need to redefine the subgenera and sections within it. PMID:26203413

  11. Isolation of Cryptococcus neoformans var. neoformans from bird droppings, fruits and vegetables in Mexico City.

    PubMed

    López-Martínez, R; Castañón-Olivares, L R

    1995-01-01

    The presence of Cryptococcus neoformans in various natural sources, such as bird droppings, fruits and vegetables, was investigated. A total of 711 samples were analyzed; C. neoformans var. neoformans was isolated from seven out of 74 bird droppings (9.5%), with parrots as one of the most significant sources. Fruits were positive in 9.5% of the 169 samples studied, specially citrus fruits, particularly grapefruit, in which the highest frequency was found. From the 468 vegetable samples, only 20 were positive (4.2%). It is emphasized that five of the positive vegetables species are autochthonous to Mexico: avocado (Nectandra salicifolia), beet (Beta vulgaris var. quinopodiace), chayote (Sechium edule), stringbean (Cassia sp), and nopal (Opuntia ficus-indica). PMID:7617014

  12. Macroparasite community in molluscs of a tidal basin in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Thieltges, David W.; Krakau, Manuela; Andresen, Henrike; Fottner, Silke; Reise, Karsten

    2006-12-01

    We provide a quantitative inventory of macroparasites in intertidal molluscs from a tidal basin in the Wadden Sea (eastern North Sea). Gastropods and bivalves contained a species rich macroparasite community consisting of trematodes (26 species), turbellarians (1), nematodes (1), copepods (2) and polychaetes (1) in 3,800 host individuals from 10 host species. Highest parasite burdens were observed in the gastropods Hydrobia ulvae and Littorina littorea and in the bivalves Cerastoderma edule and Mytilus edulis. In contrast, only one parasite species and no trematodes were found in Crepidula fornicata. The parasite community in the molluscs was similar to other Western European localities but some parasite species showed obvious differences, related to the large-scale distribution of intermediate and final hosts. Parasitism seems to be a common phenomenon in molluscs of the Wadden Sea and hence the detrimental effects observed in experiments can be expected to frequently happen in the field.

  13. Environmental effects of the growth rate of intertidal invertebrates and some implications for foraging waders

    NASA Astrophysics Data System (ADS)

    Wanink, Jan H.; Zwarts, Leo

    The paper describes effects of intertidal height and sediment type on growth rate of the bivalves Cerastoderma edule, Macoma balthica, Mya arenaria, Mytilus edulis and Scrobicularia plana, and of the worms Arenicola marina, Nephtys hombergii and Nereis diversicolor in the eastern part of the Dutch Wadden Sea. In most species, exposure time was negatively correlated with length growth, although interfering effects of sediment type could not be ruled out. When controlled for the effects of exposure time, clay content of the sediment appeared to affect the growth of all species, but in different ways. The variation was related to the foraging methods of the invertebrates. Foraging waders may use the spatial variation in growth rate of the invertebrates to optimize the exploitation of individual cohorts.

  14. Use of genomic probes to detect hepatitis A virus and enterovirus RNAs in wild shellfish and relationship of viral contamination to bacterial contamination.

    PubMed Central

    Le Guyader, F; Apaire-Marchais, V; Brillet, J; Billaudel, S

    1993-01-01

    Genomic probes were used to investigate hepatitis A virus (HAV) and enterovirus RNAs in two types of shellfish from natural beds (Atlantic coast, France). After elution concentration, nucleic acid extracted by proteinase K and purified by phenol-chloroform and ethanol precipitation was assayed by dot blot hybridization. The probes used were a specific HAV probe corresponding to the 3' end (3D polymerase coding region) and an enterovirus probe corresponding to the 5' noncoding region. The method was first tested under experimental conditions by using virus-spiked shellfish before being applied under field conditions. Our results show that shellfish were highly contaminated: enterovirus and HAV RNAs were found in 63 and 67%, respectively, of samples examined with the riboprobes. On the same site, viral (HAV and enterovirus) RNAs were found in a larger fraction of cockles than mussels. Statistical tests of dependence showed no relationship between viral contamination and bacterial contamination (evaluated by fecal coliform counts). Images PMID:8285700

  15. Shell microstructure of the late Carboniferous rostroconch mollusc Apotocardium lanterna (Branson, 1965)

    USGS Publications Warehouse

    Rogalla, N.S.; Carter, J.G.; Pojeta, J., Jr.

    2003-01-01

    The Late Carboniferous bransoniid conocardioidean Apotocardium lanterna (Branson, 1965) had an entirely aragonitic shell with a finely prismatic outer shell layer, a predominantly crossed lamellar to complex crossed lamellar middle shell layer, and an "inner" shell layer of finely textured porcelaneous and/or matted structure. This "inner" layer is probably homologous with the inner part of the middle shell layer and the inner layer sensu stricto of bivalved molluscs. Shell morphological and microstructural convergences between conocardioids and living heart cockles suggest that at least some conocardioids may have farmed algal endosymbionts in their posterior mantle margins. This symbiosis may have helped conocardioids compete with the biomechanically more efficient bivalves during the latter part of the Paleozoic.

  16. Combined toxicity of mercury and plastic wastes to crustacean and gastropod inhabiting the waters in Kuwait.

    PubMed

    Bu-Olayan, A H; Thomas, B V

    2015-11-01

    The present study determined total mercury (T-Hg) in crustacean Portunus pelagicus (blue crab) and mollusc Tapes sulcarius (Furrowed Venus: Cockle) following suspected rise in beach plastic wastes and their effect on marine organisms. Live samples were collected from beaches representing six Kuwait Governorate areas and exposed to toxicity (96hr) and bio accumulation tests for 180 d with inclusion of plastic wastes and environmental conditions simulated in laboratory. Results revealed high T-Hg concentrations in T sulcarius (1.44ng l(-1)) compared to P. pelagicus (1.03ng l(-1)) during winter than summer, with bio accumulation factor (BAF) > 1 labelled these species as hyper-accumulators. Significantly, combination of T-Hg concentrations from plastic wastes and in seawater validated the possibilities of detrimental effects of other marine lives besides deteriorating the aesthetic values of scenic beaches and likelihood of invasive species in such coastal areas. PMID:26688963

  17. Accumulation of polychlorinated biphenyls in turbot (Scophthalmus maximus) from seawater sediments and food

    NASA Astrophysics Data System (ADS)

    Courtney, W. A. M.; Langston, W. J.

    1980-03-01

    Juvenile turbot, Scophthalmus maximus (L.), were exposed to 0.58 µg 1-1 Aroclor 1254 in seawater, to sediments containing 100, 60 and 1 ppm or fed with cockle containing 20 ppm PCB (polychlorinated biphenyls). Concentration factors for liver and muscle were 104 and 103, respectively, for uptake of PCB from seawater. Contamination of muscle was similar to that of sediments containing 1 and 60 ppm PCB to which turbot were exposed, but less than the 20 ppm in their experimental diet. Contamination of flatfish in the North Sea area is compared with the levels of PCB in the flounder, Platichthys flesus (L.), in the River Thames and predictable values for uptake of PCB from different pathways discussed.

  18. Intra-specific variability in life-history traits of Anadara tuberculosa (Mollusca: Bivalvia) in the mangrove ecosystem of the Southern coast of Ecuador.

    PubMed

    Flores, Luis; Licandeo, Roberto; Cubillos, Luis A; Mora, Elba

    2014-06-01

    Anadara tuberculosa is one of the most important bivalves along the Western Pacific coast because of its commercial value. Nevertheless, the variability in growth, long-life span, natural mortality and reproductive parameters of this mangrove cockle has not yet been described. The aim of this study was to analyze these life-history traits in three areas of the Southern coast of Ecuador. Empirical and length-based methods were used to estimate these biological parameters. Body size data were collected from the commercial fishery between 2004 and 2011 in landing ports near to the Archipelago of Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) and Puerto Hualtaco (PH)]. The von Bertalanffy growth parameters for combined sex were estimated between 70.87 to 93.45mm for L(infinity) and 0.22 to 0.80/year for k. The growth indices (PHI') ranged from 3.17 to 3.85, while the overall growth performance (OGP) ranged from 5.03 to 5.82. The mean of long-life span (t(max)), size and age at maturity (L50% and t50%) were estimated in 7.71 +/- 2.53 years, 39.13 +/- 2.24mm and 1.46 +/- 0.56 years for PB; 9.51 +/- 2.85 years, 37.78 +/- 1.95mm and 1.37 +/- 0.41 years for PJ and 5.81 +/- 2.11 years, 39.73 +/- 3.31mm and 0.94 +/- 0.41 years for PH. Natural mortality (M) ranged from 0.46 to 1.28/year. We concluded that significant intra-specific variation was observed in a temporal scale in PHI' and OGP indices as well as L50% and M. Therefore, temporal changes in these life-history traits should be taken into account when assessing the status of the mangrove cockle fishery. PMID:25102632

  19. Matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry for the determination of paraben preservatives in mollusks.

    PubMed

    Villaverde-de-Sáa, Eugenia; Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2016-08-12

    A method for the extraction and determination of seven parabens, esters of 4-hydroxybenzoic acid, widely used as preservatives in personal care products, pharmaceuticals, etc., and two chlorinated derivatives (mono- and di-chloro methyl paraben) from mollusk samples was developed by combining matrix solid-phase dispersion (MSPD) and liquid chromatography-tandem mass spectrometry. MSPD parameters, such as solvent, solid support and clean-up sorbent, were optimized. Besides, since blank problems were observed for some parabens, these were investigated and blanks were tackled by precleaning all sorbents prior to use. Under final conditions, 0.5g of freeze-dried mollusk were dispersed with 1.2g of silica and packed into a cartridge containing 3g of C18, as on-line clean-up sorbent. This cartridge was eluted with 10mL of acetonitrile, evaporated and reconstituted in methanol for analysis. In the validation stage, successful linearity (R(2)>0.999), recoveries (between 71 and 117% for most analytes), precision (RSD lower than 21%) and limits of detection and quantification (LOD and LOQ, lower than 0.4 and 1.4ngg(-1) dry weight respectively) levels were achieved. Finally, the new methodology was applied to mussel, clam and cockle samples. Methyl paraben was above the LOQ in five of the six samples (not found in one clam sample) at concentrations up to 7ngg(-1) dry weight. Ethyl paraben was found above the LOQ in mussel and cockle samples at a concentration level around 0.3ngg(-1). n-Propyl paraben was only above the LOQ in one mussel sample. PMID:27401811

  20. Effects of pollination timing and distance on seed production in a dioecious weed Silene latifolia

    NASA Astrophysics Data System (ADS)

    Anderson, Jay F.; Duddu, Hema S. N.; Shirtliffe, Steven J.; Benaragama, Dilshan; Syrovy, Lena D.; Stanley, Katherine A.; Haile, Teketel A.

    2015-11-01

    Silene latifolia Poir. (white cockle or white campion) is an important invasive weed in North American agriculture. It exhibits dioecy, therefore, both male and female plants are required in order for seed production to occur. However, dioecious species being invasive is not common because of their limitations in pollination and subsequent seed production. The objective of this study is to determine the effect of pollination timing and distance on seed production of Silene latifolia. A series of experiments including pollination exclusion, timing and pollination distance were conducted in 2009 and 2010 at or around Saskatoon, Saskatchewan. For pollination exclusion, exclosures were built around the natural female plants for exclosure, sham-exclosure, and male and female combined treatments. Pollination timing was studied by applying exclosure, non-exclosure, night-exclosure, and day-exclosure treatments to individual female plants. Female plants were transplanted along a linear interval at six different distances from the pollen source to study the effect of pollination distance. S. latifolia was exclusively insect-pollinated and pollination occurred both day and night; however, in one year, pollination occurred mainly at night. Female plants that were in the range of 0-4 m from a compatible pollen source experienced no limitation to pollination. However, when the distance was increased further up to 128 m, pollination levels and subsequent seed production were declined. Moreover, there were differences in seed production between years suggesting that pollination was affected by the environmental conditions during pollination and the crop that white cockle was grown in. These experiments indicate that seed production in S. latifolia is limited by insect-pollination. Although there was pollination limitation for seed production at greater distances from a pollen source, the high fecundity rate (3000-18000 seeds per plant) resulted in a large seed output. Thus, we

  1. Are metallothioneins equally good biomarkers of metal and oxidative stress?

    PubMed

    Figueira, Etelvina; Branco, Diana; Antunes, Sara C; Gonçalves, Fernando; Freitas, Rosa

    2012-10-01

    Several researchers investigated the induction of metallothioneins (MTs) in the presence of metals, namely Cadmium (Cd). Fewer studies observed the induction of MTs due to oxidizing agents, and literature comparing the sensitivity of MTs to different stressors is even more scarce or even nonexistent. The role of MTs in metal and oxidative stress and thus their use as a stress biomarker, remains to be clearly elucidated. To better understand the role of MTs as a biomarker in Cerastoderma edule, a bivalve widely used as bioindicator, a laboratory assay was conducted aiming to assess the sensitivity of MTs to metal and oxidative stressors. For this purpose, Cd was used to induce metal stress, whereas hydrogen peroxide (H2O2), being an oxidizing compound, was used to impose oxidative stress. Results showed that induction of MTs occurred at very different levels in metal and oxidative stress. In the presence of the oxidizing agent (H2O2), MTs only increased significantly when the degree of oxidative stress was very high, and mortality rates were higher than 50 percent. On the contrary, C. edule survived to all Cd concentrations used and significant MTs increases, compared to the control, were observed in all Cd exposures. The present work also revealed that the number of ions and the metal bound to MTs varied with the exposure conditions. In the absence of disturbance, MTs bound most (60-70 percent) of the essential metals (Zn and Cu) in solution. In stressful situations, such as the exposure to Cd and H2O2, MTs did not bind to Cu and bound less to Zn. When organisms were exposed to Cd, the total number of ions bound per MT molecule did not change, compared to control. However the sort of ions bound per MT molecule differed; part of the Zn and all Cu ions where displaced by Cd ions. For organisms exposed to H2O2, each MT molecule bound less than half of the ions compared to control and Cd conditions, which indicates a partial oxidation of thiol groups in the cysteine

  2. How do mineral coatings affect dissolution rates? An experimental study of coupled CaCO 3 dissolution—CdCO 3 precipitation

    NASA Astrophysics Data System (ADS)

    Cubillas, Pablo; Köhler, Stephan; Prieto, Manuel; Causserand, Carole; Oelkers, Eric H.

    2005-12-01

    Coupled CaCO 3 dissolution-otavite (CdCO 3) precipitation experiments have been performed to 1) quantify the effect of mineral coatings on dissolution rates, and 2) to explore the possible application of this coupled process to the remediation of polluted waters. All experiments were performed at 25°C in mixed-flow reactors. Various CaCO 3 solids were used in the experiments including calcite, aragonite, and ground clam, mussel, and cockle shells. Precipitation was induced by the presence of Cd(NO 3) 2 in the inlet solution, which combined with aqueous carbonate liberated by CaCO 3 dissolution to supersaturate otavite. The precipitation of an otavite layer of less than 0.01 μm in thickness on calcite surfaces decreases its dissolution rate by close to two orders of magnitude. This decrease in calcite dissolution rates lowers aqueous carbonate concentrations in the reactor such that the mixed-flow reactor experiments attain a steady-state where the reactive fluid is approximately in equilibrium with otavite, arresting its precipitation. In contrast, otavite coatings are far less efficient in lowering aragonite, and ground clam, mussel, and cockle shell dissolution rates, which are comprised primarily of aragonite. A steady-state is only attained after the precipitation of an otavite layer of 3-10 μm thick; the steady state CaCO 3 dissolution rate is 1-2 orders of magnitude lower than that in the absence of otavite coatings. The difference in behavior is interpreted to stem from the relative crystallographic structures of the dissolving and precipitating minerals. As otavite is isostructural with respect to calcite, it precipitates by epitaxial growth directly on the calcite, efficiently slowing dissolution. In contrast, otavite's structure is appreciably different from that of aragonite. Thus, it will precipitate by random three dimensional heterogeneous nucleation, leaving some pore space at the otavite-aragonite interface. This pore space allows aragonite

  3. Bivalve growth rate and isotopic variability across the Barents Sea Polar Front

    NASA Astrophysics Data System (ADS)

    Carroll, Michael L.; Ambrose, William G.; Locke V, William L.; Ryan, Stuart K.; Johnson, Beverly J.

    2014-02-01

    Analysis of bivalve shell increments provides a means to reconstruct long-term patterns in growth histories and assess factors that regulate marine ecosystems, while tissue stable isotopes are indicators of food sources and trophic dynamics. We examined shell growth patterns and tissue stable isotopic composition (δ13C and δ15N) of the hairy cockle (Ciliatocardium ciliatum) in the northwest Barents Sea to evaluate the influence of different water masses and the Polar Front on growth rates and food sources and to assess the influence of climatic variability on ecological processes over seasonal to decadal scales. Shell growth rates were highest in Atlantic water, intermediate in Arctic water, and lowest at the Polar Front. Temporal patterns of ontogenetically-adjusted growth (SGI) were negatively correlated with the Atlantic Multidecadal Oscillation (AMO), local precipitation and ice-free days. The highest growth occurred during colder periods with more sea ice, while lower growth was associated with warmer periods and less sea ice. Stable isotope values of lipid-extracted tissues from Atlantic water cockles were enriched in δ13C by up to 2.1‰ and δ15N by 1.5‰ compared to animals from Arctic waters. Distinct seasonal and water mass variations in stable isotopic values reflect spatial and temporal variability in food supplies to the bivalves in this region on small spatial scales. Overall, Atlantic waters supported the highest growth rates, the most complex trophic webs, and the greatest sensitivity to interannual variability in environmental conditions. Bivalves from Arctic waters were the most distinct of the three groups in their response to regional climate forcing and local environmental manifestations of those conditions. The Polar Front exhibits growth and isotopic characteristics predominantly of the Atlantic domain. These results demonstrate that integrating results of sclerochronological and stable isotopic analyses of benthic bivalves provide

  4. Influence of environmental gradients on the distribution of benthic resources available for shorebirds on intertidal mudflats of Yves Bay, France

    NASA Astrophysics Data System (ADS)

    Philippe, Anne S.; Pinaud, David; Cayatte, Marie-Laure; Goulevant, Cyril; Lachaussée, Nicolas; Pineau, Philippe; Karpytchev, Mikhail; Bocher, Pierrick

    2016-06-01

    The case study of Yves Bay (Pertuis Charentais, France) highlighted links between environmental gradients (i.e. sediment characteristics and emersion time) and prey distribution and availability for the two most numerous shorebird species overwintering in Yves Bay: the red knot Calidris canutus and the dunlin Calidris alpina. Two hundred and fifty-two stations were sampled on a predetermined 250 m regular grid covering the intertidal mudflats of this major wintering site in France for east-Atlantic migratory shorebirds. The distribution of principal benthic species abundance and biomass was modelled along two environmental gradients: sediment structure (particularly pronounced north-south sand-mud gradient) and emersion time. The effect of emersion time combined with sedimentary structure strongly explained abundances and biomasses of the main prey for C. canutus and C. alpina in the bay (Cerastoderma edule, Hydrobia ulvae, Macoma balthica, Scrobicularia plana, and Nephtys hombergii). This study highlighted prey species-specific spatial segregation/overlapping as well as spatial interferences in the trophic niche of the two shorebirds.

  5. Vasoactive and antioxidant activities of plants used in Mexican traditional medicine for the treatment of cardiovascular diseases.

    PubMed

    Ibarra-Alvarado, C; Rojas, A; Mendoza, S; Bah, M; Gutiérrez, D M; Hernández-Sandoval, L; Martínez, M

    2010-07-01

    This study demonstrated that the aqueous extracts of plants employed in Mexican traditional medicine for the treatment of cardiovascular diseases are able to modify the tone of arterial smooth muscle. Agastache mexicana (Kunth) Lint & Epling (Labiatae), Chenopodium murale L. (Chenopodiaceae), Chirantodendron pentadactylon Larreat (Sterculiaceae), Dracocephalum moldavica L. (Labiatae), Psittacanthus calyculatus G. Don (Loranthaceae), Prunus serotina ssp. capuli (Cav. ex Spreng) McVaugh (Rosaceae), and Sechium edule Sw. (Cucurbitaceae) contain secondary metabolites that promote vascular relaxation and display antioxidant activities. As expected, their antioxidant effects showed a significant correlation with the polyphenolics content. However, a lower correlation was found between the antioxidant activity and the maximum vasodilatory effect, suggesting that the vasodilatation elicited by the plant extracts could be only partly attributed to their antioxidant properties. The extract of P. calyculatus, which displayed a maximum vasorelaxant effect that was higher than that of acetylcholine, induced endothelium-dependent vasodilatation. Futhermore, the vasorelaxant response to the P. calyculatus extract was reduced after adding an inhibitor of soluble guanylate cyclase activity, providing evidence that the NO/cGMP pathway is involved. On the other hand, the extracts of Bocconia frutescens L. (Papaveraceae), Magnolia grandiflora L. (Magnoliaceae), and Solanum rostratum Dunal (Solanaceae) induced concentration-dependent contraction of rat aortic rings, suggesting that these plants have potential health benefits for the treatment of ailments such as venous insufficiency. The pharmacological activities of the extracts studied provide scientific support for their ethnomedical use. PMID:20645769

  6. Spatial and inter-annual variability of the macrobenthic communities within a coastal lagoon (Óbidos lagoon) and its relationship with environmental parameters

    NASA Astrophysics Data System (ADS)

    Carvalho, Susana; Moura, Ana; Gaspar, Miguel B.; Pereira, Paula; Cancela da Fonseca, Luís; Falcão, Manuela; Drago, Teresa; Leitão, Francisco; Regala, João

    2005-05-01

    The present work aims to analyse spatial and inter-annual variability in the benthic environment within the Óbidos lagoon, assessing the relationships between environmental characteristics and macrobenthic distribution patterns. Sediment samples were collected in February 2001 and 2002 for the study of macrofauna and biogeochemical parameters (sediment grain size, organic matter, organic carbon, chlorophyll a, and phaeopigments). Comparing 2001 to 2002, a general increase in the number of species, diversity and equitability indices was observed throughout the study area. Likewise, there was an increase of phytopigments and organic matter contents in the upper sediment layer. Based on the macrobenthic community patterns and environmental variables three main areas could be distinguished in both years: an outer area near the inlet mostly influenced by the sea, with very depressed number of species and abundance, and dominated by Saccocirrus papillocercus, Lekanesphaera levii, Microphthalmus similis and Nephtys cirrosa; an intermediate area located in the central part of the lagoon characterized by sandy sediment and low organic carbon, and colonized by a high diverse community with Hydrobia ulvae, Cerastoderma edule and Abra ovata as the most characteristic species; and the innermost area of the lagoon with muddy enriched sediments dominated by Heteromastus filiformis, oligochaetes, Scrobicularia plana, Cyathura carinata, Corophium acherusicum, phoronids, insect larvae and Corbula gibba. Deposit-feeders were dominant in the muddy sediments from the inner area, where suspension-feeders were also abundant. Carnivores were associated with clean sandy sediments from the inlet area and herbivores were more abundant within the central area.

  7. Metals in sediments and benthic organisms in the Mersey estuary

    NASA Astrophysics Data System (ADS)

    Langston, W. J.

    1986-08-01

    Concentrations of twelve metals were determined in sediments, seaweed ( Fucus vesiculosus), winkles ( Littorina littorea), polychaetes ( Nereis diversicolor), suspension feeding bivalves ( Mytilus edulis, Cerastoderma edule) and deposit feeding bivalves ( Macoma balthica, Scrobicularia plana) collected from the Mersey estuary between April 1980 and June 1984. Sediments and organisms in the Mersey are moderately contaminated with most of the metals measured, but mercury concentrations are consistently higher than in other United Kingdom estuaries. Comparisons with other sites in the North West of England indicate that mercury residues in organisms, though primarily dependent on sediment concentrations, are also influenced by complexation with particulate organic matter which reduces the availability of mercury. The biological availability of arsenic in Mersey sediments is similarly influenced by complexation with iron oxyhydroxides. Nereis diversicolor and Macoma balthica are the most suitable indicator species in terms of abundance and widespread distribution along the estuary, and, for the majority of metals, tissue concentrations increase upstream, reflecting corresponding gradients in sediment contamination. However mid-estuarine peaks for tin, chromium copper and nickel in Nereis indicate more localised inputs to the estuary. Correlations between lead in sediments and organisms are poor; it is suggested that hydrophilic alkyl lead compounds may be the predominant biologically available forms. Progressive reductions in mercury contamination in sediments and mercury and lead in organisms have occurred in recent years, which coincide with efforts to reduce inputs of these metals to teh Mersey estuary.

  8. Antioxidant Activity in Extracts of 27 Indigenous Taiwanese Vegetables

    PubMed Central

    Chao, Pi-Yu; Lin, Su-Yi; Lin, Kuan-Hung; Liu, Yu-Fen; Hsu, Ju-Ing; Yang, Chi-Ming; Lai, Jun-You

    2014-01-01

    The objectives of this study were to identify the antioxidants and antioxidant axtivity in 27 of Taiwan’s indigenous vegetables. Lycium chinense (Lc), Lactuca indica (Li), and Perilla ocymoides (Po) contained abundant quercetin (Que), while Artemisia lactiflora (Al) and Gynura bicolor (Gb) were rich in morin and kaempferol, respectively. Additionally, Nymphoides cristata (Nc) and Sechium edule (Se)-yellow had significantly higher levels of myricetin (Myr) than other tested samples. Cyanidin (Cyan) and malvidin (Mal) were abundant in Gb, Abelmoschus esculentus Moench (Abe), Po, Anisogonium esculentum (Retz.) Presl (Ane), Ipomoea batatas (Ib)-purple, and Hemerocallis fulva (Hf)-bright orange. Relatively high levels of Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorption capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenger were generated from extracts of Toona sinensis (Ts) and Po. Significant and positive correlations between antioxidant activity and polyphenols, anthocyanidins, Que, Myr, and morin were observed, indicating that these phytochemicals were some of the main components responsible for the antioxidant activity of tested plants. The much higher antioxidant activity of Po, Ts, and Ib (purple leaf) may be related to their higher Cyan, Que, and polyphenol content. PMID:24858497

  9. Antioxidant activity in extracts of 27 indigenous Taiwanese vegetables.

    PubMed

    Chao, Pi-Yu; Lin, Su-Yi; Lin, Kuan-Hung; Liu, Yu-Fen; Hsu, Ju-Ing; Yang, Chi-Ming; Lai, Jun-You

    2014-05-01

    The objectives of this study were to identify the antioxidants and antioxidant axtivity in 27 of Taiwan's indigenous vegetables. Lycium chinense (Lc), Lactuca indica (Li), and Perilla ocymoides (Po) contained abundant quercetin (Que), while Artemisia lactiflora (Al) and Gynura bicolor (Gb) were rich in morin and kaempferol, respectively. Additionally, Nymphoides cristata (Nc) and Sechium edule (Se)-yellow had significantly higher levels of myricetin (Myr) than other tested samples. Cyanidin (Cyan) and malvidin (Mal) were abundant in Gb, Abelmoschus esculentus Moench (Abe), Po, Anisogonium esculentum (Retz.) Presl (Ane), Ipomoea batatas (Ib)-purple, and Hemerocallis fulva (Hf)-bright orange. Relatively high levels of Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorption capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenger were generated from extracts of Toona sinensis (Ts) and Po. Significant and positive correlations between antioxidant activity and polyphenols, anthocyanidins, Que, Myr, and morin were observed, indicating that these phytochemicals were some of the main components responsible for the antioxidant activity of tested plants. The much higher antioxidant activity of Po, Ts, and Ib (purple leaf) may be related to their higher Cyan, Que, and polyphenol content. PMID:24858497

  10. Larval supply of predator and prey: temporal mismatch between crabs and bivalves after a severe winter in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Strasser, Matthias; Günther, Carmen-Pia

    2001-08-01

    Enhanced bivalve recruitment after severe winters is a well-known phenomenon in the coastal North Sea. By comparing the bivalve larval abundances in the northern Wadden Sea after a severe (1995/96), a moderate (1996/97) and a mild (1997/98) winter we found no evidence for the hypothesis that high bivalve recruitment after severe winters is caused by enhanced larval supply. Total and peak abundances of all bivalve larvae as well as of each of four separate species Ensis americanus, Mytilus edulis, Cerastoderma edule and Mya arenaria were three to six times lower after the severe than after the mild winter. In Macoma balthica total and peak abundances after the severe winter were only slightly higher than after the moderate winter. The larvae of the epibenthic predator Carcinus maenas appeared in lower numbers and six to eight weeks later after the severe winter than after the moderate and the mild winter. Since the bivalve larvae appeared without, or with less, delay after the severe winter, there was a temporal mismatch between Carcinus and the bivalves, supporting the hypothesis that reduced epibenthic predation is an important factor in high bivalve recruitment after severe winters.

  11. Are flatfish nursery grounds richer in benthic prey?

    NASA Astrophysics Data System (ADS)

    Wouters, Noémie; Cabral, Henrique N.

    2009-08-01

    The density of macrobenthos was evaluated in the nursery grounds for flatfish of six estuarine systems along the coast of Portugal by comparison with adjacent non-nursery areas. The dry weight and density of macrobenthic fauna were significantly higher in the nursery grounds. Polychaeta, Bivalvia, Oligochaeta and Isopoda were found to be significantly more abundant in the nursery than in the non-nursery grounds. For Isopoda and Bivalvia, total dry weight was also significantly higher in the nursery areas. Correspondence analysis based on density showed that the nursery areas of the different estuaries grouped together relative to non-nursery sites, with a relative similarity in the abundance of Oligochaeta, Spionidae, Amage spp., Scrobicularia plana and Cerastoderma edule. Taking into consideration the generally opportunistic feeding ecology and low dietary selectivity of the flatfish species, the results indicated higher prey availability in the nursery grounds of the Portuguese estuaries, an important factor contributing to the quality of these areas. The relatively high macrobenthic productivity in the nursery areas might be linked to physical and biological interactions favouring the recruitment and maintenance of the communities.

  12. Assessing the role of benthic filter feeders on phytoplankton production in a shellfish farming site: Mont Saint Michel Bay, France

    NASA Astrophysics Data System (ADS)

    Cugier, Philippe; Struski, Caroline; Blanchard, Michel; Mazurié, Joseph; Pouvreau, Stéphane; Olivier, Frédéric; Trigui, Jihane R.; Thiébaut, Eric

    2010-07-01

    The macrobenthic community of Mont Saint Michel Bay (English Channel, France) is mainly dominated by filter feeders, including cultivated species (oysters and mussels). An ecological model of the bay was developed, coupling a 2D hydro-sedimentary model and two biological models for primary production and filter-feeder filtration. The filter-feeder model includes three cultivated species ( Mytilus edulis, Crassostrea gigas and Ostrea edulis), one invasive species ( Crepidula fornicata) and eight wild native species ( Abra alba, Cerastoderma edule, Glycymeris glycymeris, Lanice conchilega, Macoma balthica, Paphia rhomboides, Sabellaria alveolata, andSpisula ovalis). For cultivated and invasive species, the production of biodeposits was computed to assess their role in restimulating primary production. Chlorophyll a concentrations appeared to be strongly controlled by the filter feeders. When the pressure of each benthic compartment on phytoplankton was estimated separately wild species and the invasive slipper limpet C.fornicata were shown to be key elements in the control of primary production. Conversely, the role of cultivated species, particularly oysters, was weaker. Feedback due to the mineralization of biodeposits also appears to be crucial to fully evaluate the role of filter feeders in primary production.

  13. Role of acyl carrier protein isoforms in plant lipid metabolism: Progress report

    SciTech Connect

    Ohlrogge, J.B.

    1989-01-01

    Previous research from my lab has revealed that several higher plant species have multiple isoforms of acyl carrier protein (ACP) and therefore this trait appears highly conserved among higher plants. This level of conservation suggests that the existence of ACP isoforms is not merely the results of neutral gene duplications. We have developed techniques to examine a wider range of species. Acyl carrier proteins can be labelled very specifically and to high specific activity using H-palmitate and the E. coli enzyme acyl-ACP synthetase. Isoforms were then resolved by western blotting and native PAGE of H-palmitate labelled ACP's. Multiple isoforms of ACP were observed the leaf tissue of the monocots Avena sativa and Hordeum vulgare and dicots including Arabidopsis thallina, Cuphea wrightii, and Brassica napus. Lower vascular plants including the cycad, Dioon edule, Ginkgo biloba, the gymnosperm Pinus, the fern Anernia phyllitidis and Psilotum nudum, the most primitive known extant vascular plant, were also found to have multiple ACP isoforms as were the nonvascular liverwort, Marchantia and moss, Polytrichum. Therefore, the development of ACP isoforms occurred early in evolution. However, the uniellular alge Chlamydomonas and Dunaliella and the photosynthetic cyanobacteria Synechocystis and Agmnellum have only a single elecrophotetic form of ACP. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants.

  14. A Mixed Modeling Approach to Predict the Effect of Environmental Modification on Species Distributions

    PubMed Central

    Cozzoli, Francesco; Eelkema, Menno; Bouma, Tjeerd J.; Ysebaert, Tom; Escaravage, Vincent; Herman, Peter M. J.

    2014-01-01

    Human infrastructures can modify ecosystems, thereby affecting the occurrence and spatial distribution of organisms, as well as ecosystem functionality. Sustainable development requires the ability to predict responses of species to anthropogenic pressures. We investigated the large scale, long term effect of important human alterations of benthic habitats with an integrated approach combining engineering and ecological modelling. We focused our analysis on the Oosterschelde basin (The Netherlands), which was partially embanked by a storm surge barrier (Oosterscheldekering, 1986). We made use of 1) a prognostic (numerical) environmental (hydrodynamic) model and 2) a novel application of quantile regression to Species Distribution Modeling (SDM) to simulate both the realized and potential (habitat suitability) abundance of four macrozoobenthic species: Scoloplos armiger, Peringia ulvae, Cerastoderma edule and Lanice conchilega. The analysis shows that part of the fluctuations in macrozoobenthic biomass stocks during the last decades is related to the effect of the coastal defense infrastructures on the basin morphology and hydrodynamics. The methodological framework we propose is particularly suitable for the analysis of large abundance datasets combined with high-resolution environmental data. Our analysis provides useful information on future changes in ecosystem functionality induced by human activities. PMID:24586545

  15. Disturbance of benthic infauna by sediment-reworking activities of the lugworm Arenicola marina

    NASA Astrophysics Data System (ADS)

    Flach, E. C.

    The influence of the lugworm Arenicola marina on the abundance of other benthic species was studied in the westernmost part of the Wadden Sea. Small squares (1 m 2) within depopulated 144-m 2 plots were recolonized with various (naturally-occurring) lugworm densities (0-10-20-40-80 and 0-25-50-75-100 per m 2). These plots were sampled during the summer. Lugworms were found to have a strongly negative effect on the densities of C. volutator. At 0-density lugworms, the numbers of C. volutator were high. These were halved at 17 lugworms per m 2 ( i.e. the mean density on the tidal flats of the Dutch Wadden Sea), and were further reduced at higher lugworm densities ( e.g. 20% remained at 40 lugworms per m 2). Laboratory observations of Corophium behaviour in the presence of Arenicola suggest that sediment-reworking lugworms stimulate Corophium to emigrate. Effects of lugworms on other benthic species were also studied in the same way. Lugworms were found to have strongly negative effects on the juvenile densities of various worm and bivalve species ( Nereis diversicolor, Nephtys hombergii, Heteromastus filiformis, Scoloplos armiger, Pygospio elegans, Capitella capitata and Mya arenaria, Cerastoderma edule, Macoma balthica, Angulus tenuis, respectively).

  16. Influence of environmental gradients on the distribution of benthic resources available for shorebirds on intertidal mudflats of Yves Bay, France

    NASA Astrophysics Data System (ADS)

    Philippe, Anne S.; Pinaud, David; Cayatte, Marie-Laure; Goulevant, Cyril; Lachaussée, Nicolas; Pineau, Philippe; Karpytchev, Mikhail; Bocher, Pierrick

    2016-06-01

    The case study of Yves Bay (Pertuis Charentais, France) highlighted links between environmental gradients (i.e. sediment characteristics and emersion time) and prey distribution and availability for the two most numerous shorebird species overwintering in Yves Bay: the red knot Calidris canutus and the dunlin Calidris alpina. Two hundred and fifty-two stations were sampled on a predetermined 250 m regular grid covering the intertidal mudflats of this major wintering site in France for east-Atlantic migratory shorebirds. The distribution of principal benthic species abundance and biomass was modelled along two environmental gradients: sediment structure (particularly pronounced north-south sand-mud gradient) and emersion time. The effect of emersion time combined with sedimentary structure strongly explained abundances and biomasses of the main prey for C. canutus and C. alpina in the bay (Cerastoderma edule, Hydrobia ulvae, Macoma balthica, Scrobicularia plana, and Nephtys hombergii). This study highlighted prey species-specific spatial segregation/overlapping as well as spatial interferences in the trophic niche of the two shorebirds.

  17. Evolutionary and tissue-specific control of expression of multiple acyl-carrier protein isoforms in plants and bacteria.

    PubMed

    Battey, J F; Ohlrogge, J B

    1990-02-01

    We have examined the occurrence of multiple acyl-carrier protein (ACP), isoforms in evolutionarily diverse species of higher and lower plants. Isoforms were resolved by native polyacrylamide gel electrophoresis (PAGE), and were detected by Western blotting or fluorography of [(3)H]-palmitate-labelled ACPs. Multiple isoforms of ACP were found in leaf tissue of the monocotyledons Avena sativa and Hordeum vulgare and dicotyledons Arabidopsis thaliana, Cuphea wrightii, and Brassica napus. Lower vascular plants including the lycopod Selaginella krausseriana, the gymnosperms Ephedra sp. and Dioon edule, the ferns Davallia feejensis and Marsilea sp. and the most primitive known extant vascular plant, Psilotum nudum, were all found to have multiple ACP isoforms, as were the nonvascular liverworts, Lunularia sp. and Marchantia sp. and the moss, Polytrichum sp. Therefore, the development of ACP isoforms appears to have occurred early in plant evolution. However, we could detect only a single electrophoretic form of ACP in the unicellular algae Chlamydomonas reinhardtii and Dunaliella tertiolecta and the photosynthetic cyanobacteria Synechocystis strain 6803 and Agmnellum quadruplicatum. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants. We have also examined tissue specificity and light control over the expression of ACP isoforms. The relative abundance of multiple forms of ACP in leaf of Spinacia and Avena was altered very little by light. Rather, the different patterns of ACP isoforms were primarily dependent on the tissue type. PMID:24202013

  18. Biology of Anastrepha grandis (Diptera: Tephritidae) in Different Cucurbits.

    PubMed

    Bolzan, Anderson; Nava, Dori E; Garcia, Flávio R M; Valgas, Ricardo A; Smaniotto, Giovani

    2015-06-01

    Anastrepha grandis (Macquart) (Diptera: Tephritidae) is one of the main pests of cucurbits in Brazil. Losses occur due to the damage caused to the fruits and the embargo on exports, as A. grandis is considered a quarantine pest in countries that import Brazilian cucurbits. This study aimed to evaluate the development of A. grandis in hosts of the Cucurbitaceae family. The hosts used were stem squash (Cucurbita pepo L.), squash (Cucurbita moschata Duchesne), chayote [Sechium edule (Jacq.) Swartz], mini watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai], Spanish melon (Cucumis melo L.), hybrid squash "Tetsukabuto" (C. moschata×Cucurbita maxima Duchesne), and salad cucumber (Cucumis sativus L.). We evaluated the viability and duration of egg-to-pupa period, pupal weight, sex ratio, and average number of pupae per fruit under controlled conditions of temperature, relative humidity, and photophase. The preoviposition and oviposition periods, fecundity, fertility, and longevity of females were determined for adults. Hosts of the genus Cucurbita provided a better development of A. grandis in comparison with other hosts, and presented a greater number of insects on fruit as well as higher infestation rate. Fecundity and longevity were also higher for females that developed in hosts of the genus Cucurbita, although values of these biological parameters varied between stem squash, squash, hybrid squash "Tetsukabuto." PMID:26470226

  19. Contribution to the understanding of the cycle of the protozoan parasite Marteilia refringens.

    PubMed

    Arzul, I; Chollet, B; Boyer, S; Bonnet, D; Gaillard, J; Baldi, Y; Robert, M; Joly, J P; Garcia, C; Bouchoucha, M

    2014-02-01

    The paramyxean parasite Marteilia refringens infects several bivalve species including European flat oysters Ostrea edulis and Mediterranean mussels Mytilus galloprovincialis. Sequence polymorphism allowed definition of three parasite types 'M', 'O' and 'C' preferably detected in oysters, mussels and cockles respectively. Transmission of the infection from infected bivalves to copepods Paracartia grani could be experimentally achieved but assays from copepods to bivalves failed. In order to contribute to the elucidation of the M. refringens life cycle, the dynamics of the infection was investigated in O. edulis, M. galloprovincialis and zooplankton over one year in Diana lagoon, Corsica (France). Flat oysters appeared non-infected while mussels were infected part of the year, showing highest prevalence in summertime. The parasite was detected by PCR in zooplankton particularly after the peak of prevalence in mussels. Several zooplanktonic groups including copepods, Cladocera, Appendicularia, Chaetognatha and Polychaeta appeared PCR positive. However, only the copepod species Paracartia latisetosa showed positive signal by in situ hybridization. Small parasite cells were observed in gonadal tissues of female copepods demonstrating for the first time that a copepod species other than P. grani can be infected with M. refringens. Molecular characterization of the parasite infecting mussels and zooplankton allowed the distinguishing of three Marteilia types in the lagoon. PMID:24128728

  20. Morphogenesis of thin hyperelastic plates: A constitutive theory of biological growth in the Föppl-von Kármán limit

    NASA Astrophysics Data System (ADS)

    Dervaux, Julien; Ciarletta, Pasquale; Ben Amar, Martine

    2009-03-01

    The shape of plants and other living organisms is a crucial element of their biological functioning. Morphogenesis is the result of complex growth processes involving biological, chemical and physical factors at different temporal and spatial scales. This study aims at describing stresses and strains induced by the production and reorganization of the material. The mechanical properties of soft tissues are modeled within the framework of continuum mechanics in finite elasticity. The kinematical description is based on the multiplicative decomposition of the deformation gradient tensor into an elastic and a growth term. Using this formalism, the authors have studied the growth of thin hyperelastic samples. Under appropriate assumptions, the dimensionality of the problem can be reduced, and the behavior of the plate is described by a two-dimensional surface. The results of this theory demonstrate that the corresponding equilibrium equations are of the Föppl-von Kármán type where growth acts as a source of mean and Gaussian curvatures. Finally, the cockling of paper and the rippling of a grass blade are considered as two examples of growth-induced pattern formation.

  1. Norovirus and other human enteric viruses in moroccan shellfish.

    PubMed

    Benabbes, Laila; Ollivier, Joanna; Schaeffer, Julien; Parnaudeau, Sylvain; Rhaissi, Houria; Nourlil, Jalal; Le Guyader, Françoise S

    2013-03-01

    The aim of this study was to evaluate the presence of human enteric viruses in shellfish collected along the Mediterranean Sea and Atlantic Coast of Morocco. A total of 77 samples were collected from areas potentially contaminated by human sewage. Noroviruses were detected in 30 % of samples, with an equal representation of GI and GII strains, but were much more frequently found in cockles or clams than in oysters. The method used, including extraction efficiency controls, allowed the quantification of virus concentration. As in previous reports, results showed levels of contamination between 100 and 1,000 copies/g of digestive tissues. Sapoviruses were detected in 13 % of samples mainly in oyster and clam samples. Hepatitis A virus was detected in two samples, with concentrations around 100 RNA copies/g of digestive tissues. Only two samples were contaminated with enterovirus and none with norovirus GIV or Aichi virus. This study highlights the interest of studying shellfish samples from different countries and different production areas. A better knowledge of shellfish contamination helps us to understand virus levels in shellfish and to improve shellfish safety, thus protecting consumers. PMID:23412717

  2. Application of viability PCR to discriminate the infectivity of hepatitis A virus in food samples.

    PubMed

    Moreno, L; Aznar, R; Sánchez, G

    2015-05-18

    Transmitted through the fecal-oral route, the hepatitis A virus (HAV) is acquired primarily through close personal contact and foodborne transmission. HAV detection in food is mainly carried out by quantitative RT-PCR (RT-qPCR). The discrimination of infectious and inactivated viruses remains a key obstacle when using RT-qPCR to quantify enteric viruses in food samples. Initially, viability dyes, propidium monoazide (PMA) and ethidium monoazide (EMA), were evaluated for the detection and quantification of infectious HAV in lettuce wash water. Results showed that PMA combined with 0.5% Triton X-100 (Triton) was the best pretreatment to assess HAV infectivity and completely eliminated the signal of thermally inactivated HAV in lettuce wash water. This procedure was further evaluated in artificially inoculated foods (at concentrations of ca. 6×10(4), 6×10(3) and 6×10(2)TCID50) including lettuce, parsley, spinach, cockles and coquina clams. The PMA-0.5% Triton pretreatment reduced the signal of thermally inactivated HAV between 0.5 and 2 logs, in lettuce and spinach concentrates. Moreover, this pretreatment reduced the signal of inactivated HAV by more than 1.5 logs, in parsley and ten-fold diluted shellfish samples inoculated at the lowest concentration. Overall, this pretreatment (50 μM PMA-0.5% Triton) significantly reduced the detection of thermally inactivated HAV, depending on the initial virus concentration and the food matrix. PMID:25720326

  3. Distribution, biomass, recruitment and productivity of Anadara senilis (L.) (Mollusca: Bivalvia) on the banc d'Arguin, Mauritania

    NASA Astrophysics Data System (ADS)

    Wolff, W. J.; Gueye, Abou; Meijboom, A.; Piersma, Th.; Alassane Sall, Mamadou

    Data on distribution, ecology, biomass, recruitment, growth, mortality and productivity of the West African bloody cockle Anadara senilis were collected at the Banc d'Aguuin, Mauritania, in early 1985 and 1986. Ash-free dry weight appeared to be correlated best with shell height. A. senilis was abundant on the tidal flats of landlocked coastal bays, but nearly absent on the tidal flats bordering the open sea. The average biomass for the entire area of tidal flats was estimated at 5.5 g·m -2 ash-free dry weight. The A. senilis population appeared to consist mainly of 10 to 20-year-old individuals, showing a very slow growth and a production: biomass ratio of about 0.02 y -1. Recruitment appeared negligible and mortality was estimated to be about 10% per year. Oystercatchers ( Haematopus ostralegus), the gastropod Cymbium cymbium and unknown fish species were responsible for a large share of this. The distinction of annual growth marks permitted the assessment of year-class strength, which appeared to be correlated with the average discharge of the river Senegal. This may be explained by assuming that year-class strength and river discharge both are correlated with rainfall at the Banc d'Arguin.

  4. Osteoblasts growth behaviour on bio-based calcium carbonate aragonite nanocrystal.

    PubMed

    Shafiu Kamba, Abdullahi; Zakaria, Zuki Abu Bakar

    2014-01-01

    Calcium carbonate (CaCO3) nanocrystals derived from cockle shells emerge to present a good concert in bone tissue engineering because of their potential to mimic the composition, structure, and properties of native bone. The aim of this study was to evaluate the biological response of CaCO3 nanocrystals on hFOB 1.19 and MC3T3 E-1 osteoblast cells in vitro. Cell viability and proliferation were assessed by MTT and BrdU assays, and LDH was measured to determine the effect of CaCO3 nanocrystals on cell membrane integrity. Cellular morphology was examined by SEM and fluorescence microscopy. The results showed that CaCO3 nanocrystals had no toxic effects to some extent. Cell proliferation, alkaline phosphatase activity, and protein synthesis were enhanced by the nanocrystals when compared to the control. Cellular interactions were improved, as indicated by SEM and fluorescent microscopy. The production of VEGF and TGF-1 was also affected by the CaCO3 nanocrystals. Therefore, bio-based CaCO3 nanocrystals were shown to stimulate osteoblast differentiation and improve the osteointegration process. PMID:24734228

  5. Environmental regulation of bivalve growth in the southern Barents Sea: A combined ecological and geochemical approach

    NASA Astrophysics Data System (ADS)

    Carroll, M. L.; Johnson, B. J.; Henkes, G. A.; McMahon, K. W.; Voronkov, A.; Ambrose, W. G., Jr.; Denisenko, S. G.

    2009-04-01

    Ecological and geochemical analyses of bivalve shells provide potentially complimentary information on patterns and drivers of natural variability in Arctic marine populations, yet are rarely considered together. We analyzed growth rates and shell geochemistry of the Greenland Smooth Cockle (Serripes groenlandicus) from the southern Barents Sea between 1882 and 1968. Growth, stable isotope (oxygen and carbon), and trace elemental (Mg, Sr, Ba, Mn) patterns were linked to environmental variations on weekly to decadal scales. Standardized growth rates exhibited multi-year periodicity inversely related to the North Atlantic Oscillation Index (NAO) and positively related to river discharge. Up to 60% of the interannual variability in Ba/Ca could be explained by variations in river discharge at stations closest to the rivers, but the relationship disappeared at a more distant location. Stable isotope data (18O, 13C), and Sr/Ca patterns suggest that bivalve growth ceases at elevated temperatures during the fall and recommences at the coldest temperatures in the early spring, implying that food, rather than temperature, is the primary driver of the annual growth cycle. Combining annually-integrated growth results and higher resolution geochemical results thus elucidated the annual growth cycle of an Arctic bivalve and mechanisms of biophysical coupling over a range of temporal and spatial scales.

  6. An analysis of mussel bed habitats in the Dutch Wadden Sea

    NASA Astrophysics Data System (ADS)

    Brinkman, A. G.; Dankers, N.; van Stralen, M.

    2002-04-01

    A habitat suitability analysis for littoral mussel beds in the Dutch Wadden Sea was carried out. The analysis was based on the presence of mussel beds in the years 1960-1970, and a number of environmental characteristics: wave action, flow velocity, median grain size, emersion times and distance to a gully border. The habitat model describes mussel bed appearance quantitatively. It predicts the distribution of mussel beds quite well, as well as the distribution of spatfall in the years 1994 and 1996. From the analysis we found that wave action (maximum orbital velocity) was the main structuring factor. A low orbital velocity was preferred. Neither very low, nor maximum flow velocities were favourable for mussel beds. Very coarse sands or silty environments were not preferred. Sites close to the low water line showed lower mussel bed appearance; when emersion time was above 50% , hardly any mussel beds could be found. The habitat suitability analysis and the construction of a habitat suitability map was performed in the framework of the discussions on a further or reduced exploitation of the tidal flats in the Dutch Wadden Sea by cockle and mussel fishery activities.

  7. Utilization of ground waste seashells in cement mortars for masonry and plastering.

    PubMed

    Lertwattanaruk, Pusit; Makul, Natt; Siripattarapravat, Chalothorn

    2012-11-30

    In this research, four types of waste seashells, including short-necked clam, green mussel, oyster, and cockle, were investigated experimentally to develop a cement product for masonry and plastering. The parameters studied included water demand, setting time, compressive strength, drying shrinkage and thermal conductivity of the mortars. These properties were compared with those of a control mortar that was made of a conventional Portland cement. The main parameter of this study was the proportion of ground seashells used as cement replacement (5%, 10%, 15%, or 20% by weight). Incorporation of ground seashells resulted in reduced water demand and extended setting times of the mortars, which are advantages for rendering and plastering in hot climates. All mortars containing ground seashells yielded adequate strength, less shrinkage with drying and lower thermal conductivity compared to the conventional cement. The results indicate that ground seashells can be applied as a cement replacement in mortar mixes and may improve the workability of rendering and plastering mortar. PMID:22841935

  8. A 6000 year tropical cyclone record from Western Australia

    NASA Astrophysics Data System (ADS)

    Nott, Jonathan

    2011-03-01

    This study provides the first long-term tropical cyclone record from the Indian Ocean region. Multiple shore parallel ridges composed entirely of one species of marine cockle shell ( Fragum eragatum) standing between 3 and 6 m above mean sea level occur at Hamelin Pool, Shark Bay, Western Australia. The ridges record a tropical cyclone history between approximately 500 cal BP and 6000-7000 cal BP. Numerical storm surge and shallow water wave modelling techniques have been applied to determine the intensity (central pressure with uncertainty margins) of the storms responsible for deposition of the ridges, which has occurred approximately every 190-270 years. The ridges also record a 1700 year gap in tropical cyclone activity, between approximately 5400 cal BP and 3700 cal BP, where ridges deposited prior to this time were buried by a substantial deposit of aeolian fine-grained terrestrial sediment. The presence of this sedimentary unit suggests that this 1700 year period was characterised by a very dry climate; possibly the driest phase experienced in this region since the mid-Holocene. The absence of tropical cyclones at this time and the occurrence of this mega-drought may be linked.

  9. Mollusc-Microbe Mutualisms Extend the Potential for Life in Hypersaline Systems

    NASA Astrophysics Data System (ADS)

    Hickman, Carole S.

    2003-11-01

    Metazoans in extreme environments have evolved mutualisms with microbes that extend the physical and chemical capabilities of both partners. Some of the best examples are bivalve molluscs in evaporite and hypersaline settings. Mollusc tissue is developmentally and evolutionarily amenable to housing vast numbers of symbiotic microbes. Documented benefits to the host are nutritional. Multiple postulated benefits to the microbes are related to optimizing metabolic performance at interfaces, where heterogeneity and steep gradients that cannot be negotiated by microbes can be spanned by larger metazoan hosts. A small cockle, Fragum erugatum, and its photosymbiotic microbes provide a remarkable example of a mutualistic partnership in the hypersaline reaches of Shark Bay, Western Australia. Lucinid bivalves and their endosymbiotic chemolithotrophic bacteria provide examples in which hosts span oxic/anoxic interfaces on behalf of their symbionts at sites of seafloor venting. Multiple lines of evidence underscore the antiquity of mutualisms and suggest that they may have played a significant role in life's first experiments above the prokaryotic grade of complexity. The study of metazoan-microbe mutualisms and their signatures in extreme environments in the geologic record will provide a significant augmentation to microbial models in paleobiology and astrobiology. There are strong potential links between mutualisms and the early history of life on Earth, the persistence of life in extreme environments at times of global crisis and mass extinction, and the possibilities for life elsewhere in the universe.

  10. Curling Edges: A Problem that Has Plagued Scrolls for Millennia

    NASA Astrophysics Data System (ADS)

    Chou, Ming-Han; Shen, Wei-Chao; Wang, Yi-Ping; Hung, Sun-Hsin; Hong, Tzay-Ming

    2014-01-01

    Qi-Wa refers to the up curl on the lengths of hand scrolls and hanging scrolls, which has troubled Chinese artisans and emperors for as long as the art of painting and calligraphy has existed. This warp is unwelcome not only for aesthetic reasons, but its potential damage to the fiber and ink. Although it is generally treated as a part of the cockling and curling due to moisture, consistency of paste, and defects from the mounting procedures, we demonstrate that the spontaneous extrinsic curvature incurred from the storage is in fact more essential to understanding and curing Qi-Wa. In contrast to the former factors whose effects are less predictable, the plastic deformation and strain distribution on a membrane are a well-defined mechanical problem. We study this phenomenon by experiments, theoretical models, and molecular dynamics simulation, and obtain consistent scaling relations for the Qi-Wa height. This knowledge enables us to propose modifications on the traditional mounting techniques that are tested on real mounted paper to be effective at mitigating Qi-Wa. By experimenting on polymer-based films, we demonstrate the possible relevance of our study to the modern development of flexible electronic paper.