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Sample records for crassostrea rhizophorae collected

  1. Temporal distribution of heavy metal concentrations in oysters Crassostrea rhizophorae from the central Venezuelan coast.

    PubMed

    Alfonso, Juan A; Handt, Helga; Mora, Abrahan; Vásquez, Yaneth; Azocar, José; Marcano, Eunice

    2013-08-15

    The oyster Crassostrea rhizophorae is a bivalve abundant in Venezuelan estuaries and consumed by local populations. No known values have been reported on trace metals in oysters from the central Venezuelan coast. We report the concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn in the soft parts of C. rhizophorae, which were collected bimonthly between March 2008 and March 2009, at two sampling areas from the Central Venezuelan Coast: Buche estuary and Mochima estuary. Our results show that for each metal there is a similar temporal variation pattern. The concentrations of the heavy metals reported in this work are useful as reliable baselines and can be used for comparison in future environment studies. Concentrations in C. rhizophorae from the Buche estuary can be interpreted to be high on a global scale for Cd, Cu, Ni and Mn, indicating atypically raised bioavailabilities. PMID:23746942

  2. Perkinsus sp. infecting oyster Crassostrea rhizophorae (Guilding, 1828) on the coast of Bahia, Brazil.

    PubMed

    Brandão, Rosana Pinho; Boehs, Guisla; Sabry, Rachel Costa; Ceuta, Liliane Oliveira; Luz, Mariane Dos Santos Aguiar; Queiroga, Fernando Ramos; da Silva, Patrícia Mirella

    2013-02-01

    This study investigated the occurrence of the protozoan Perkinsus in the oyster Crassostrea rhizophorae on the coast of Bahia State, Brazil. The oysters (n = 900) were collected in February-March and July-August 2010. The Ray's fluid thioglycollate medium (RFTM) analysis of gills and rectum revealed hypnospores of Perkinsus sp. with a high mean prevalence (63%). The infection intensity varied from very light to advanced. The polymerase chain reaction confirmed Perkinsus in 87.2% of the RFTM-positive oysters. Histological analysis showed trophozoites and schizonts phagocytized by hemocytes, mainly in the intestine and the stomach epithelium. PMID:23201453

  3. Polycyclic aromatic hydrocarbons (PAHs) in Crassostrea rhizophorae and Cathorops spixii from the Caroni Swamp, Trinidad, West Indies.

    PubMed

    Kanhai, La Daana K; Gobin, Judith F; Beckles, Denise M; Lauckner, Bruce; Mohammed, Azad

    2015-01-01

    Dietary exposure to polycyclic aromatic hydrocarbons (PAHs) may pose serious threats to human health. However, within the Caribbean, quantitative assessments regarding the risks associated with dietary PAH exposure remain sparse. This study investigated PAH presence in edible biota from the Caroni Swamp and quantitatively assessed the potential health threat to human consumers. Mangrove oysters (Crassostrea rhizophorae) and Madamango sea catfish (Cathorops spixii) collected from seven sites in the Caroni Swamp were analysed for 16 priority PAHs. Total PAH levels ranged from 109 ± 18.4 to 362 ± 63.0 ng/g dry wt. in Crassostrea rhizophorae and 7.5 ± 0.9 to 43.5 ± 25.5 ng/g dry wt. in Cathorops spixii (average ± standard deviation). Benzo[a]pyrene levels in Crassostrea rhizophorae at all sites exceeded international guidelines from British Colombia (Canada) and the European Union (EU). Incremental lifetime cancer risk (ILCR) values based on the ingestion of Crassostrea rhizophorae ranged from 8.4 × 10(-6) to 1.6 × 10(-5) and slightly exceeded the commonly used 1 × 10(-6) acceptable level of risk. Information from this study is important in understanding the potential health risks posed by PAHs, it is critical towards the protection of public health, and it serves as a useful baseline for comparison with future work. PMID:25142345

  4. Perkinsus sp. infecting the oyster Crassostrea rhizophorae from estuaries of the septentrional Northeast, Brazil.

    PubMed

    Dantas-Neto, M P; Sabry, R C; Ferreira, L P; Romão, L S; Maggioni, R

    2015-11-01

    The mangrove oyster Crassostrea rhizophorae is an estuarine resource exploited by riverside communities in Northeast Brazil. Despite its socioeconomic importance, studies on the health status of this bivalve are scanty in this region. The purpose of the present study was to investigate the presence of the protozoan Perkinsus sp. in C. rhizophorae collected in August and September 2011 in three estuaries of the septentrional Northeast, Brazil: Jaguaribe (Ceará), Camurupim (Piauí) and Carnaubeiras (Maranhão) (n= 150 specimens/site). The samples were submitted to Ray's fluid thioglycollate medium (RFTM), PCR and histology assays. The RFTM assay revealed spherical, blue or bluish-black hypnospores of the genus Perkinsus in 50 specimens (Jaguaribe= 17.3%, Camurupim= 5.3%, Carnaubeiras= 10.6%). The intensity of the infection ranged from very light (1-10 cells per slide) to severe (more than 40 cells in each of 10 fields of the slide) for Jaguaribe; very light for Camurupim and very light to moderate (at least 40 cells observed in each of 10 fields of the slide) for Carnaubeiras. When submitted to confirmatory PCR analysis, 6 cases were confirmed (Jaguaribe=3, Camurupim=1, Carnaubeiras=2). The histology confirmed 21 cases of infection in specimens from the three estuaries. Although local collectors have reported no mortality in oyster populations that might be attributed to infection by Perkinsus, health surveillance of oyster populations in the septentrional region of Northeast Brazil is advisable. PMID:26675922

  5. Parasitological survey of mangrove oyster, Crassostrea rhizophorae, in the Pacoti River Estuary, Ceará State, Brazil.

    PubMed

    Sabry, Rachel Costa; Gesteira, Tereza Cristina Vasconcelos; Magalhães, Aimê Rachel Magenta; Barracco, Margherita Anna; Guertler, Cristhiane; Ferreira, Liana Pinho; Vianna, Rogério Tubino; da Silva, Patrícia Mirella

    2013-01-01

    The mangrove oyster, Crassostrea rhizophorae (Bivalvia, Ostreidae) is commonly collected by fisherwomen in the estuaries of the Ceará State (CE), Northeastern Brazil. Despite the socioeconomic importance of this natural resource, there are few studies on the health of the oysters in this region. This study aimed to survey pathological changes in the mangrove oyster C. rhizophorae in the estuary of the Pacoti River, CE. Adult oysters were collected in August 2008 (N=450) and December 2009 (N=450) at three sites of the Pacoti estuary and in 2010 (N=600) samplings were done quarterly at one site which has showed the higher prevalence de Perkinsus. Macroscopical and histological analyses were used to evaluate pathological changes, Ray's Fluid Thioglycollate Medium (RFTM) to detect Perkinsus spp. and polymerase chain reactions (PCR) and DNA sequencing to identify Perkinsus species. In 2009, RFTM assay detected Perkinsus sp. infecting the tissues of C. rhizophorae with low prevalences of 1.3%, 6.7% e 7.3% in sites 1, 2 and 3, respectively, and in 2010, in site 3, prevalence was 2% (12 of 600 oysters). PCR did not confirm any positive case in 2009 and only 5 in 2010. The phylogenetic analyses strongly indicate that the Perkinsus species infecting oysters C. rhizophorae of this study belongs to Perkinsus beihaiensis. The histology confirmed 11 cases of Perkinsus sp. infecting the C. rhizophorae in 2009, and only two cases in 2010. Nematopsis sp. was the protozoan observed with greater prevalence (up 96.7%). Other found protozoa were: Trichodina, Sphenophrya, Ancistrocoma - like and an unknown ovarian parasite. The metazoa found were the polychaete Polydora with high prevalences, a turbellarian, possibly of the genus Urastoma, an unidentified digenean metacercariae and larvae of cestode Tylocephalum. A continuous monitoring of diseases in bivalves from this natural population is recommended, since the phylogenetic analyses indicate the occurrence of P. beihaiensis

  6. Evaluation of impacted Brazilian estuaries using the native oyster Crassostrea rhizophorae: Branchial carbonic anhydrase as a biomarker.

    PubMed

    Azevedo-Linhares, Maristela; Freire, Carolina A

    2015-12-01

    In this study, we investigated the use of branchial carbonic anhydrase activity in a sessile filter feeding species, the oyster Crassostrea rhizophorae, as a biomarker. The oysters were collected in three human impacted Brazilian estuaries, following a crescent latitudinal gradient: in Pernambuco state (Itamaracá), in Espírito Santo state (Piraquê), and in Paraná state (Paranaguá), in August/2003 (Winter in the southern hemisphere) and February/2004 (Summer). Three sites were chosen in each estuary for oyster sampling: Reference (R), Contaminated 1 (C1, close to industrial/harbor contamination), and Contaminated 2 (C2, near to sewage discharges). Comparing to values in oysters sampled in reference sites, there was apparent inhibition in carbonic anhydrase activity (CAA) in gills of oysters from C1 of Itamaracá and from C2 of Piraquê, both cases in Summer. On the other hand, increased CAA was noted in C2 oysters of Itamaracá in winter, and of Paranaguá, in both seasons. Branchial CAA in C. rhizophorae was thus very responsive to coastal contamination. Data are consistent with its usefulness as a supporting biomarker for inexpensive and rapid analysis in the assessment of estuaries using a sessile osmoconformer species, but preferably allied to other biomarkers and with knowledge on the suite of contaminants present. PMID:26410193

  7. First report of Perkinsus sp. infecting mangrove oysters Crassostrea rhizophorae from the Brazilian coast.

    PubMed

    Sabry, Rachel Costa; Rosa, Rafael Diego; Magalhães, Aimê Rachel Magenta; Barracco, Margherita Anna; Gesteira, Tereza Cristina Vasconcelos; da Silva, Patricia Mirella

    2009-12-22

    Protozoan parasites of the genus Perkinsus are considered important pathogens responsible for mass mortalities in several mollusk species worldwide. In the present study we describe for the first time a parasite of the genus Perkinsus infecting the mangrove oyster Crassostrea rhizophorae from the Brazilian coast. Prevalence of this parasite was low in the Pacoti River estuary (Ceará, northeast Brazil) and absent in oysters from southern Brazil. Oyster gill and rectum tissues incubated in Ray's fluid thioglycollate medium (RFTM) revealed the presence of spherical hypnospores (5 to 55 microm diam.). Histological analysis showed the occurrence of typical signet-ring trophozoites and schizonts (3 to 6 microm diam.) infecting connective tissues of several organs and digestive epithelia. PCR assays specific to the genus Perkinsus, followed by cloning and sequencing of the internal transcribed spacer (ITS) region of the ribosomal ribonucleic acid (rRNA) gene complex, confirmed a close phylogenetic relationship between Brazilian Perkinsus sp. and P. beihaiensis infecting Chinese oysters. PMID:20183961

  8. Polycyclic aromatic hydrocarbons (PAHs) in surface sediment and oysters (Crassostrea rhizophorae) from mangrove of Guadeloupe: levels, bioavailability, and effects.

    PubMed

    Ramdine, Gaëlle; Fichet, Denis; Louis, Max; Lemoine, Soazig

    2012-05-01

    Surface sediment and oysters (Crassostrea rhizophorae) from the coastlines of Guadeloupe were analysed for polycyclic aromatic hydrocarbons (PAHs) using GC/MS. Biomarkers of oxidative stress were used to assess the response of these oysters to hydrocarbons exposure. The total concentration of PAHs in the sediment ranged from 49 to 1065 ng/g dw, while concentrations in oyster ranged from 66 to 961 ng/g dw. Molecular indices based on isomeric PAHs ratios characterize the pollution sources and show that most of the contaminations in sediment originate from pyrolytic inputs. Bioaccumulation factors (BAFs) have been related to isomeric ratio calculated for oysters in order to refine PAHs sources. The variations of BAFs observed in the different compounds resulted from different uptake pathways in the mangrove oysters according to the type of inputs. Response of biomarkers showed inhibition of catalase and an increase of lipid peroxidation at the station where PAHs concentrations were the highest. Taken together, data obtained point to the relevance of considering environmental conditions as factors influencing biomarker responses in environmental monitoring programs. These data also indicate the need for regular environmental follow-up studies in Guadeloupe. PMID:22209019

  9. First report of the protozoan parasite Perkinsus marinus in South America, infecting mangrove oysters Crassostrea rhizophorae from the Paraíba River (NE, Brazil).

    PubMed

    da Silva, Patricia Mirella; Vianna, Rogério Tubino; Guertler, Cristhiane; Ferreira, Liana Pinho; Santana, Lucas Nunes; Fernández-Boo, Sergio; Ramilo, Andrea; Cao, Asunción; Villalba, Antonio

    2013-05-01

    The present work aimed to study the infection by Perkinsus sp. in the mangrove oysters Crassostrea rhizophorae from the estuary of the Paraíba River (Paraíba State, Brazil). Perkinsosis was detected by incubation of oyster gill pieces in Ray's fluid thioglycollate medium. The monthly prevalence values were all above 70%, thus infection was not likely to be a transient event. Perkinsus sp. parasites isolated from eight oysters were propagated in vitro. PCR-RFLP analysis of in vitro cultured cells as well as the sequences of the rDNA ITS region allowed the identification of the in vitro propagated parasites as Perkinsus marinus. Phylogenetic analyses using rDNA ITS region sequences strongly supported the Perkinsus sp. from Paraíba in a monophyletic group with P. marinus. Thus, the results confirmed the species affiliation of Paraíba Perkinsus sp. as P. marinus. This is the first report of P. marinus in Brazil and South America and the first report of P. marinus naturally infecting C. rhizophorae. PMID:23439264

  10. Estimating the gasoline components and formulations toxicity to microalgae (Tetraselmis chuii) and oyster (Crassostrea rhizophorae) embryos: An approach to minimize environmental pollution risk

    SciTech Connect

    Paixao, J.F.; Nascimento, I.A. . E-mail: iracema@ftc.br; Pereira, S.A.; Leite, M.B.L.; Carvalho, G.C.; Silveira, J.S.C.; Reboucas, M.; Matias, G.R.A.; Rodrigues, I.L.P.

    2007-03-15

    Even though petrochemical contamination frequently occurs in the form of oil spills, it is thought that a greater danger to coastal habitats is posed by chronic petrochemical toxicity associated with urban run-off, in which gasoline water-soluble-fraction (WSF) plays an important role. The hypothesis of the entrepreneurs, who were associated to the scientists uncharged of this research, was that recycled petrochemical waste may provide different gasoline formulations, having different toxic properties; the correlation between the gasoline formulations and their components' toxicological effects might contribute to the reformulation of the products, in such a way that the gasoline generated could be less toxic and less harmful to the environment. The aim of this research was to determine the toxic effects of 14 different types of gasoline (formulated, in accordance with National Petroleum Agency standards, from petrochemical waste), on Tetraselmis chuii (microalgae culture) and Crassostrea rhizophorae (embryos). Microalgae and oyster embryos were exposed to different gasoline formulations water-soluble fractions (WSF) at a range of concentrations (0%, 4.6%, 10.0%, 22.0%, 46.0%, and 100%), for 96 and 24 h, respectively. The tests were carried out under controlled conditions. End-points have been CI50-96h (concentration causing 50% growth inhibition in microalgae cultures) and EC50-24h (concentration causing abnormalities on 50% of the exposed embryos). Through these procedures, gasoline formulations, which represent the lowest environmental risk, were selected. Bioassays carried out on the 8 different gasoline components aimed to correlate gasoline toxicity with the toxic potential of its components. The analysis of principal components showed that the C9DI, a mixture of aromatic hydrocarbons of 9 carbon atoms, had the highest level of toxic potential, followed by C9S (a mixture of aromatics with 9-11 carbon atoms) and heavy naphtha. The results showed gasoline

  11. PARASITIC AND SYMBIONIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) COLLECTED FROM THE CALOOSAHATCHEE RIVER AND ESTUARY, FLORIDA

    EPA Science Inventory



    Studies of oysters, Crassostrea virginica, collected from ten sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic fauna that have never been reported from this area. Organisms observed included ovacystis virus infecting gametes...

  12. [Community structure of bivalves and gastropods in roots of red mangrove Rhizophora mangle (Rhizophoraceae) in isla Larga, Mochima Bay, Venezuela].

    PubMed

    Acosta Balbas, Vanessa; Betancourt Tineo, Rafael; Prieto Arcas, Antulio

    2014-06-01

    The Rhizophora mangle roots form a complex ecosystem where a wide range of organisms are permanently established, reproduce, and find refuge. In this study, we assessed the diversity of bivalves and gastropods that inhabit red mangrove roots, in isla Larga, Mochima, Venezuela Sucre state. Bimonthly collections were made from January 2007 to May 2008, in four study areas denominated: South, North, East and West. In each area, five mangrove roots were sampled, and the specimens were obtained. We analyzed a total of 180 roots and a total of 35 bivalve species and 25 gastropod species were found. The most abundant bivalves were: Isognomon alatus, Isognomon bicolor, Ostrea equestris, Crassostrea rhizophorae and Brachidontes exustus; among gastropods, the most common where: Littorina angulifera, (Cymatium pileare and Diodora cayenensis. The months with the highest abundances and number of individuals for both groups were January and July 2007, and March 2008. The mangrove ecosystem in isla Larga, presented a number of individuals and species higher than those reported for other regions in Venezuela and the Caribbean. PMID:25102639

  13. Phages infecting Vibrio vulnificus are abundant and diverse in oysters (Crassostrea virginica) collected from the Gulf of Mexico.

    PubMed

    DePaola, A; Motes, M L; Chan, A M; Suttle, C A

    1998-01-01

    Phages infecting Vibrio vulnificus were abundant (> 10(4) phages g of oyster tissue-1) throughout the year in oysters (Crassostrea virginica) collected from estuaries adjacent to the Gulf of Mexico (Apalachicola Bay, Fla.; Mobile Bay, Ala.; and Black Bay, La.). Estimates of abundance ranged from 10(1) to 10(5) phages g of oyster tissue-1 and were dependent on the bacterial strain used to assay the sample. V. vulnificus was near or below detection limits (< 0.3 cell g-1) from January through March and was most abundant (10(3) to 10(4) cells g-1) during the summer and fall, when phage abundances also tended to be greatest. The phages isolated were specific to strains of V. vulnificus, except for one isolate that caused lysis in a few strains of V. parahaemolyticus. Based on morphological evidence obtained by transmission electron microscopy, the isolates belonged to the Podoviridae, Styloviridae, and Myoviridae, three families of double-stranded DNA phages. One newly described morphotype belonging to the Podoviridae appears to be ubiquitous in Gulf Coast oysters. Isolates of this morphotype have an elongated capsid (mean, 258 nm; standard deviation, 4 nm; n = 35), with some isolates having a relatively broad host range among strains of V. vulnificus. Results from this study indicate that a morphologically diverse group of phages which infect V. vulnificus is abundant and widely distributed in oysters from estuaries bordering the northeastern Gulf of Mexico. PMID:9435088

  14. DIFFERENTIAL EFFECTS OF OYSTER (CRASSOSTREA VIRGINICA) DEFENSES ON CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO PARAHEMOLYTICUS

    EPA Science Inventory

    Three clinical (2030, 2062, and 2107) and three environmental (1094, 1163, and ATCC 17802) isolates of Vibrio parahaemolyticus were exposed to hemocytes and plasma collected from oysters (Crassostrea virginica) to determine their susceptibility to putative oyster defenses. Clinic...

  15. Pollen morphology of Rhizophora L. in Peninsular Malaysia

    SciTech Connect

    Mohd-Arrabe', A. B.; Noraini, Talip Noraini

    2013-11-27

    Rhizophora L. are common mangrove genus in Peninsular Malaysia, it contains 3 species and 1 hybrid (R. apiculata Blume, R. mucronata Lam., R. stylosa Griff., R. x lamarckii Montrouz). This genus has some unique adaptation towards extreme environment. Rhizophora has looping aerial stilt-root and uniformly viviparous. The aim of this study is to investigate the variation in the pollen morphology of Rhizophora that can be related to their habitat. Methods include in this study is pollen observation under light and acetolysis method under scanning electron microscope. Pollen type of Rhizophora species studied except hybrid species is classified tricolporate, shape spheroidal based on ratio of length polar axis/ length of equatorial axis (1.03 - 1.09). The exine ornamentation is perforate-reticulate for R. apiculata and R. mucronata, while R. stylosa is perforate. For the only hybrid in Peninsular Malaysia, R. x lamarckii (R. apiculata x R. stylosa) differs from others, tricolpate with the absence of porate, shape is subprolate and exine ornamentation is reticulate and striate in equatorial region. Pollenkitt is present due to the salty and extreme environment. This may enhance the volume of pollenkitt present surrounding the pollen grains in Rhizophora for protection and adaptation purposes. Based on these findings, it is evident that pollen morphology is somehow related to its natural habitat.

  16. COMPARATIVE FORM AND FUNCTION OF OYSTER CRASSOSTREA VIRGINICA HEMOCYTES FROM CHESAPEAKE BAY (VIRGINICA) AND APALACHICOLA BAY (FLORIDA)

    EPA Science Inventory

    Oysters (Crassostrea virginica) from Chesapeake Bay, Virginia, and Apalachicola Bay, Florida, were collected in March 1992, to determine relationships among hemocyte number, morphology and size with putative defense-related activities, including hemocyte mobility, particle bindin...

  17. [Spatial-temporal variation of the macroinvertebrate epibiont community on red mangrove prop roots Rhizophora mangle (Rhizophoraceae) at La Mancha coastal lagoon, Veracruz, Mexico].

    PubMed

    Ruiz, Marcela; López-Portillo, Jorge

    2014-12-01

    La Mancha lagoon is connected to the Gulf of Mexico through an estuarine ephemeral inlet, a sand bar, which opens during the rainy season and closes during the late fall and the winter storm season. As the lagoon fills up with the permanent stream flow into its Southern part, the water level increases and the sand bar opens up, releasing huge volumes of water into the ocean and leaving the previously flooded intertidal zone exposed to drying. In this study, we described the spatial and temporal variations of structure and composition of the community living on the surface of red mangrove prop roots, related to the hydrodynamic of the estuarine inlet. Four red mangrove prop roots were collected every three months, over an annual period, at ten sampling stations. Water temperature, salinity, dissolved oxygen, water depth and transparency were also measured at each sampling event. To describe the identity, abundance, biomass, and specific richness of epibiont coverage on the prop roots, measurements were taken at 10 cm intervals (herein called "horizons"). A total of 59,632 specimens and a total biomass of 172 g/cm2 were registered, and a maximum of eleven horizons presented at least one" species of epibionts. Two species of polychaetes, 12 of mollusks and 14 of crustaceans were identified, with Mytilopsis leucophaeata as the most abundant, Ficopomatus miamiensis as the most common and Crassostrea rhizophorae with the highest contribution in biomass. Sampling effort was assessed using species accumulation curves, resulting that the efficiency was, in general, greater than 90% of the richness predicted by asymptotic models. The hydrodynamics of the estuarine inlet had a great influence on the environmental conditions of the lagoon and on the spatial and temporal variation of the epibiont community: (a) when the inlet is open, there is a North-South gradient in environmental parameters (b) when the inlet is closed and the water level increases, the epibionts especially

  18. Maximum longevities of Rhizophora apiculata and R. mucronata propagules

    USGS Publications Warehouse

    Drexler, J.Z.

    2001-01-01

    The longevity of viviparous mangrove seedlings (propagules) in seawater is a key factor determining their ability to survive dispersal both locally and across large expanses of ocean. The purpose of this experiment was to determine the maximum longevities of propagules from two common Pacific mangrove species: Rhizophora mucronata Lamk. and Rhizophora apiculata Bl. Propagules from each of these species were placed in outdoor tubs with continously flowing seawater. The condition of each propagule was monitored until it sank or started to rot. Propagules were then planted to determine viability. After planting, 50% of R. apiculata propagules and 21% of R. mucronata propagules were viable. For both species, mortality of propagules was strongly related to the length of the floating interval. Maximum longevities for R. mucronata and R. apiculata propagules were 150 (median = 70) and 89 days (median = 7), respectively. Rhizophora mucronata propagules appeared to be better equipped for long-distance dispersal, yet had low survivorship that would decrease overall dispersal opportunities. In comparison, R. apiculata propagules had higher survivorship yet shorter longevity and, thus, appeared to be better equipped for shorter distance dispersal.

  19. Tension wood fibers are related to gravitropic movement of red mangrove (Rhizophora mangle) seedlings.

    PubMed

    Fisher, Jack B; Tomlinson, P Barry

    2002-02-01

    Freshly collected viviparous seedlings (propagules) were collected from wild plants of Rhizophora mangle and planted in vertical or horizontal positions. A total of 80 seedlings were examined anatomically at various ages and orientations. After rooting, seedlings reoriented from horizontal to vertical by extreme bending in the hook region of the hypocotyl directly above the basal 1 cm where roots formed. Hypocotyl bending occurred over many months. Trends in position and relative abundance of tension fibers (also called gelatinous fibers) over time were followed. The erection of the seedling was related to increased secondary xylem and the number of tension wood fibers on the upper side of the hook region. However, linear regressions had low coefficient of determination (r(2)) values, presumably related to seedlings with high variability. PMID:12884047

  20. Tenacibaculum crassostreae sp. nov., isolated from the Pacific oyster, Crassostrea gigas.

    PubMed

    Lee, Young Sun; Baik, Keun Sik; Park, So Yeon; Kim, Eun Mi; Lee, Dong-Heon; Kahng, Hyung-Yeel; Jeon, Che Ok; Jung, Jae Sung

    2009-07-01

    A rod-shaped, yellow-pigmented, aerobic, Gram-negative bacterium, designated strain JO-1(T), was isolated from an apparently healthy Pacific oyster, Crassostrea gigas, collected at Wan Island, Korea. It grew at 15-37 degrees C (optimum 30 degrees C) only in the presence of sea salts. Strain JO-1(T) hydrolysed casein, Tween 80 and starch. The major fatty acids were iso-C(15 : 0) (23.8 %), summed feature 3 (comprising C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH; 14.5 %) and iso-C(15 : 1) G (14.1 %). Analysis of the 16S rRNA gene sequence indicated that strain JO-1(T) was a member of the genus Tenacibaculum in the family Flavobacteriaceae, with sequence similarity of 94.6-97.8 % to the type strains of recognized members of the genus. The G+C content of the genomic DNA was 31.4 mol%. DNA-DNA relatedness levels between strain JO-1(T) and the five closest relatives, Tenacibaculum litoreum KCCM 42115(T), T. lutimaris KCTC 12302(T), T. aestuarii KCTC 12569(T), T. mesophilum DSM 13764(T) and T. adriaticum JCM 14633(T), were less than 28 %. Phylogenetic analyses and differences in physiological and biochemical characteristics suggested that strain JO-1(T) (=KCTC 22329(T) =JCM 15428(T)) should be classified as the type strain of a novel species within the genus Tenacibaculum, for which the name Tenacibaculum crassostreae sp. nov. is proposed. PMID:19542127

  1. Rhizophora mucronata var. alokii – a new variety of mangrove species from the Andaman and Nicobar Islands, India (Rhizophoraceae)

    PubMed Central

    Ragavan, P.; Mohan, P. M.; Jayaraj, R. S. C.; Ravichandran, K.; Saravanan, S.

    2015-01-01

    Abstract Rhizophora mucronata var. alokii (Rhizophoraceae), a new variety of Rhizophora from the Andaman and Nicobar Islands, India, is described and illustrated. The new variety is remarkable in having four stamens, laterally folded leaves, a short peduncle, thick leathery petals, and a four-sided ovary with a sessile style. A key for the species of Rhizophora of the Andaman and Nicobar Islands is also provided. PMID:26312036

  2. The Use of Phytochemicals to Effectively Produce Biofuel from Rhizophora mangle

    NASA Astrophysics Data System (ADS)

    Singhal, M.; Brinker, R.

    2015-12-01

    After successfully determining the presence of phytochemicals in both the Common Crabgrass (Digitaria ischaemum), and North American Dandelion (Taxacum officinale) , my research focused on the effects of specific phytochemicals, Luteolin from crabgrass and Taxasterol from dandelion, on electrical energy yield from a hydrogen fuel cell. Improvements in hydrogen fuel cell efficiency and cost are sought. By use of red mangrove (Rhizophora mangle) propagules as an oxygen source the effects of Luteolin and Taxasterol could be tested as a means to optimize hydrogen fuel cells. The methodology began with physical chemical extraction, then proceeded with separation by column chromatography, and ended with fuel cell testing of the isolated phytochemicals. Published retention factor values were used to isolate Luteolin (.66) and Taxasterol (.30). In order to test electrical energy yield, the amount of current produced by the fuel cell was measured in microamperes (μA[RB1] ) over five minutes for both the three control and three experimental group trials for both experimental groups each. The largest ampere value collected from Luteolin group was 4.3 μA, while the largest value collected from Taxasterol group was 2.5 μA. Out of both experimental groups, taraxsterol had the smallest range, showing more consistency between the control and corresponding experimental groups tested. My hypothesis was not supported. Luteolin treated fuel cell produced a larger electrical energy yield than did fuel cells treated with Taxasterol. [RB1]I found μ by selecting "insert symbol", then looking at Greek symbols.

  3. Unusual conservation of mitochondrial gene order in Crassostrea oysters: evidence for recent speciation in Asia

    PubMed Central

    2010-01-01

    Background Oysters are morphologically plastic and hence difficult subjects for taxonomic and evolutionary studies. It is long been suspected, based on the extraordinary species diversity observed, that Asia Pacific is the epicenter of oyster speciation. To understand the species diversity and its evolutionary history, we collected five Crassostrea species from Asia and sequenced their complete mitochondrial (mt) genomes in addition to two newly released Asian oysters (C. iredalei and Saccostrea mordax) for a comprehensive analysis. Results The six Asian Crassostrea mt genomes ranged from 18,226 to 22,446 bp in size, and all coded for 39 genes (12 proteins, 2 rRNAs and 25 tRNAs) on the same strand. Their genomes contained a split of the rrnL gene and duplication of trnM, trnK and trnQ genes. They shared the same gene order that differed from an Atlantic sister species by as many as nine tRNA changes (6 transpositions and 3 duplications) and even differed significantly from S. mordax in protein-coding genes. Phylogenetic analysis indicates that the six Asian Crassostrea species emerged between 3 and 43 Myr ago, while the Atlantic species evolved 83 Myr ago. Conclusions The complete conservation of gene order in the six Asian Crassostrea species over 43 Myr is highly unusual given the remarkable rate of rearrangements in their sister species and other bivalves. It provides strong evidence for the recent speciation of the six Crassostrea species in Asia. It further indicates that changes in mt gene order may not be strictly a function of time but subject to other constraints that are presently not well understood. PMID:21189147

  4. Two Perkinsus spp. infect Crassostrea gasar oysters from cultured and wild populations of the Rio São Francisco estuary, Sergipe, northeastern Brazil.

    PubMed

    da Silva, Patricia Mirella; Scardua, Marcos Paiva; Vianna, Rogério Tubino; Mendonça, Raoani Cruz; Vieira, Cairé Barreto; Dungan, Christopher F; Scott, Gail P; Reece, Kimberly S

    2014-06-01

    Brazilian production of bivalve molluscs is small but expanding, especially in the northeastern region where the native oysters Crassostrea rhizophorae and C. gasar are abundant, and tropical weather promotes their rapid growth. Studies on bivalve pathology are scarce in Brazil, with only a few employing techniques for detecting protozoan pathogens listed by the World Organisation for Animal Health (OIE). In 2008, a Perkinsus sp. was reported for the first time in Brazil, infecting C. rhizophorae oysters from a wild population in Ceará state, NE Brazil. Recently P. marinus was detected in the same oyster species in nearby Paraíba state. These findings highlighted the need to expand knowledge on the presence and impacts of Perkinsus spp. on Brazilian oyster populations. The current investigation evaluated Perkinsus sp. infections among wild and cultured C. gasar mangrove oysters from the estuary of the Rio São Francisco, Sergipe state, NE Brazil. Our results show that Perkinsus sp. infections occurred commonly in oysters of both groups, at prevalences that were frequently higher among cultured oysters. Prevalences varied seasonally, with maximum values during summer (January) of 57% and 80% for wild and cultured oysters respectively, and minimum values during winter (July). Results of DNA sequencing, in situ hybridization assays, and phylogenetic analyses showed dual- and single-pathogen infections by P. marinus and/or P. olseni in the tested oysters. PMID:24780219

  5. Occurrence of annual growth rings in Rhizophora mangle in a region with low climate seasonality.

    PubMed

    Souza, Brunna T; Estrada, Gustavo C D; Soares, Mário L G; Callado, Cátia H

    2016-01-01

    The formation of annual growth rings has been confirmed for several mangrove species in the last decade, among which is the Rhizophora mangle. However, the record of annual rings for this species was made in a region with high hydric seasonality, a widely recognized induction factor of annual rings in tropical species. In this sense, the present study aimed to verify the occurrence of annual growth rings in R. mangle in the mangroves of Guaratiba (Rio de Janeiro, Southeastern Brazil), a region with low hydric seasonality. For this purpose, the crossdating technique was applied in ten trees collected with known age (seven years). The growth rings are characterized by alternating layers of low vessel density (earlywood) and high vessel density (latewood). Multiple regression analysis indicated that growth rings width variation is driven by precipitation, water surplus, water deficit and water storage. Crossdating analysis confirmed the existence of annual growth rings in the R. mangle in Guaratiba. This discovery in a region with low hydric seasonality increases the dendrocronological potential of this species and suggests the importance of biological factors (eg. phenological behavior) as complementary inductors for the formation of growth rings in this species. PMID:27142552

  6. Changes in molecular genetic variation at ALFP loci associated with naturalization and domestication of the Pacific oyster (Crassostrea gigas)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pacific oyster (Crassostrea gigas) is an important commercial species in the US Pacific Northwest with a history of propagation first using wild-caught seed imported directly from the Miyagi region of northern Japan (1920s – 1970s) followed by an extended period of seed collection from a few sel...

  7. Taraxerol and Rhizophora pollen as proxies for tracking past mangrove ecosystems 1

    NASA Astrophysics Data System (ADS)

    Versteegh, Gerard J. M.; Schefuß, Enno; Dupont, Lydie; Marret, Fabienne; Sinninghe Damsté, Jaap S.; Jansen, J. H. Fred

    2004-02-01

    Angola Basin and Cape Basin (southeast Atlantic) surface sediments and sediment cores show that maxima in the abundance of taraxerol (relative to other land-derived lipids) covary with maxima in the relative abundance of pollen from the mangrove tree genus Rhizophora and that in the surface sediments offshore maxima in the relative abundance of taraxerol occur at latitudes with abundant coastal mangrove forests. Together with the observation that Rhizophora mangle and Rhizophora racemosa leaves are extraordinarily rich in taraxerol, this strongly indicates that taraxerol can be used as a lipid biomarker for mangrove input to the SE Atlantic. The proxy-environment relations for taraxerol and Rhizophora pollen down-core show that increased taraxerol and Rhizophora pollen abundances occur during transgressions and periods with a humid climate. These environmental changes modify the coastal erosion and sedimentation patterns, enhancing the extent of the mangrove ecosystem and/or the transport of mangrove organic matter offshore. Analyses of mid-Pleistocene sediments show that interruption of the pattern of taraxerol maxima during precession minima occurs almost only during periods of low obliquity. This demonstrates the complex environmental response of the interaction between precession-related humidity cycles and obliquity-related sea-level changes on mangrove input.

  8. Heavy metals in green mussel (Perna viridis) and oysters (Crassostrea sp.) from Trinidad and Venezuela.

    PubMed

    Rojas de Astudillo, L; Chang Yen, I; Agard, J; Bekele, I; Hubbard, R

    2002-05-01

    Heavy metal concentrations were monitored in edible soft tissues of shellfish from Trinidad and Venezuela. Oysters (Crassostrea sp.) and the green mussel (Perna viridis), which is a recently transplanted species to the Caribbean from the Far East, were collected at six locations in Venezuela and five in Trinidad, the latter along the coast line of the Gulf of Paria. Simple and low-cost methods of analysis were optimized and validated using standard reference materials. Cadmium, copper, lead, nickel, and zinc were analyzed by flame atomic absorption spectrometry. Mercury was determined by cold-vapor atomic absorption spectrometry. The present study has confirmed that oysters have a much greater capacity for accumulation of copper and zinc than does green mussel. In addition, concentrations of copper and zinc in oysters (Crassostrea sp.) at many of the sites in the Gulf of Paria exceeded local and international standards, whereas green mussel P. viridis contained generally acceptable levels for human consumption. PMID:11994781

  9. Localization of the bacterial agent of juvenile oyster disease (Roseovarius crassostreae) within affected eastern oysters (Crassostrea virginica).

    PubMed

    Boardman, Cynthia L; Maloy, Aaron P; Boettcher, Katherine J

    2008-02-01

    The bacterium Roseovarius crassostreae causes seasonal mortalities among commercially produced eastern oysters (Crassostrea virginica) grown in the Northeastern United States. Phylogenetically, the species belongs to a major lineage of marine bacteria (the Roseobacter clade), within which Roseovarius crassostreae is the only known pathogen to be isolated in laboratory culture. The objective of the current study was to determine the location and nature of R. crassostreae interactions with oysters affected by juvenile oyster disease (JOD). Scanning electron microscopy of diseased individuals revealed abundant colonization of the inner shell surfaces by bacteria which were morphologically similar to R. crassostreae. The same types of cells were also observed on and within layers of host-derived conchiolin on the inner valves. Most bacterial cells were alive as determined by the use of a fluorescent viability stain. Further, most were clearly attached at the cell poles, which is consistent with the ability of R. crassostreae to express polar fimbriae. When material from the pallial fluid, soft tissue and inner valve surfaces was cultured, the highest numbers of R. crassostreae were recovered from the inner valves. These samples also contained the greatest abundance of R. crassostreae as a percentage of total colonies. Cloning and sequencing of 16S rRNA genes provided culture-independent evidence of the numerical dominance of R. crassostreae among the bacterial consortia associated with the inner shell surfaces of JOD-affected animals. The ability of R. crassostreae to colonize shell and conchiolin is consistent with the described JOD-pathology and may aid the bacteria in avoiding hemocyte-mediated killing. PMID:17931651

  10. CHEMICAL EFFECTS ON OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTE MICROBICIDAL ACTIVITY

    EPA Science Inventory

    Oyster (Crassostrea virginica) hemocytes, or blood cells, perform important internal defense functions such as phagocytosis and intracellular destruction of pathogens and bacteria. Using techniques such as phagocytosis and chemiluminescence assays, potential impairment of hemocyt...

  11. 'PROCTOECES' SP. (TREMATODA: DIGENEA) IN THE AMERICAN OYSTER, 'CRASSOSTREA VIRGINICA'

    EPA Science Inventory

    Histological examination of over 6,000 oysters, Crassostrea virginica, inhabiting northern Gulf Coast estuaries revealed unencysted junvenile and possible adult stages of digenetic trematode, Proctoeces sp., inhabiting the gonadal ducts of the mollusc. The morphology of the worm ...

  12. Paleoenvironmental and sclerochronological reconstruction of Crassostrea gryphoides Miocene biostromes from Crete island (Greece)

    NASA Astrophysics Data System (ADS)

    Koskeridou, E.; Agiadi, K.

    2012-04-01

    The mangrove oyster Crassostrea gasar (Adanson, 1757) is a keystone species mainly along the African Atlantic coasts. It forms biostromes on muddy coasts and typically associated with river mouths in the intertidal zone in depths of 0.60 up to 1 m1. Similarly, many biostrome structures of the fossilized Crassostrea gryphoides are found within Cenozoic deposits of Greece2. Since Crassostrea gasar is the phyllogenetically corresponding species of Crassostrea gryphoides, it is investigated whether the fossil biostromes formed under environmental conditions similar to those favored by modern Crassostrea gasar and if growth rate and longevity are comparable. A biostrome from the Tortonian of Heraklion district, Crete island (southern Greece) was studied to investigate the paleoenvironmental conditions and the life history of these oysters. The shells are big, ranging up to 40 cm in length, thick and positioned mainly horizontally. The biostrome is approximately 2 m in thickness and a few meters in length. Individual oysters, associated fauna and lithologic samples were collected. Paleoenvironmental interpretation was based on the analysis of the oyster taphonomy, the associated fauna and the sclerochronology/stable isotopic geochemistry of the oyster shells. The biostrome is observed in sandy marl which laterally contains Veneridae, Melongena, Terebralia bidentata and oligospecific microfossils, mainly Ammonia beccarii and Miliolids. Borings by many ichnotaxa occur on the external and internal surface of the oyster shells during the pre and /or post-mortem. Using a micromill, successive samples were taken along the hinge/ligament region of an oyster for isotopic analyses. The δ18O values ranged from -2.9 to 0.1. The wide range of values supports the interpretation of changing environmental conditions. The δ13C values ranged from -2.6 to -0.1. A correlation between δ18O and δ13C was observed. The profiles exhibit cyclicity with respect to isotopic and Sr/Ca ratios

  13. Wind pollination and propagule formation in Rhizophora mangle L. (Rhizophoraceae): resource or pollination limitation?

    PubMed

    Nadia, Tarcila L; Machado, Isabel C

    2014-03-01

    Rhizophora mangle is considered as a self-compatible mangrove, and is pollinated by wind and insects. However, there is no information about fruit production by autogamy and agamospermy and on the foraging behavior of its flower visitors. Hence, the present study analyzed the pollination and reproductive systems of R. mangle in a mangrove community in northern Pernambuco, Brazil. Floral morphology, sequence of anthesis, and behavior of flower visitors were described; the proportion of flowers that resulted in mature propagules was also recorded. Autogamy, agamospermy, and wind pollination tests were performed, and a new anemophily index is proposed. The flowers of R. mangle are hermaphrodite, protandric, and have high P/O rate. Flies were observed on flowers only during the male phase, probably feeding on mites that consume pollen. Rhizophora mangle is not agamospermic and its fruit production rate by spontaneous self-pollination is low (2.56%) compared to wind pollination (19.44%). The anemophily index was high 0.98, and thus it was considered as a good indicator. Only 13.79% of the flowers formed mature propagules. The early stages of fruit development are the most critical and susceptible to predation. Rhizophora mangle is, therefore, exclusively anemophilous in the study area and the propagule dispersal seems to be limited by herbivory. PMID:24804313

  14. Regeneration of Rhizophora mangle in a Caribbean mangrove forest: interacting effects of canopy disturbance and a stem-boring beetle.

    PubMed

    Sousa, Wayne P; Quek, Swee P; Mitchell, Betsy J

    2003-11-01

    Current theory predicts that in low-density, seed-limited plant populations, seed predation will be more important than competition in determining the number of individuals that reach maturity. However, when plant density is high, competition for microsites suitable for establishment and growth is expected to have a relatively greater effect. This dichotomous perspective does not account for situations in which the risk of seed predation differs inside versus outside recruitment microsites. We report the results of a field experiment and sampling studies that demonstrate such an interaction between microsite quality and the risk of propagule predation in mangrove forests on the Caribbean coast of Panama, where it appears to play a key role in shaping the demography and dynamics of the mangrove, Rhizophora mangle. Rhizophora's water-borne propagules establish wherever they strand, but long-term sampling revealed that only those that do so in or near lightning-created canopy gaps survive and grow to maturity. These microsites afford better growth conditions than the surrounding understory and, as importantly, provide a refuge from predation by the scolytid beetle, Coccotrypes rhizophorae. This refuge effect was confirmed with a field experiment in which Rhizophora seedlings were planted at different positions relative to gap edges, from 5 m inside to 20 m outside the gap. Mortality due to beetle attack increased linearly from an average of 10% inside a gap to 72% at 20 m into the forest. The interaction between canopy disturbance and propagule predation may be having a large impact on the composition of our study forests. Being shade-tolerant, Rhizophora seedlings that escape or survive beetle attack can persist in the understory for years. However, the high rate of beetle-induced mortality effectively eliminates the contribution of advance regeneration by Rhizophora saplings to gap succession. This may explain why the shade-intolerant mangrove, Laguncularia racemosa

  15. Properties of Pseudomonas enalia, a Marine Bacterium Pathogenic for the Invertebrate Crassostrea gigas (Thunberg)1

    PubMed Central

    Colwell, R. R.; Sparks, A. K.

    1967-01-01

    Bacteriological investigations of dead and dying oysters in populations of Crassostrea gigas grown in Hood Canal, Oyster Bay, and Willapa Bay, Washington, were undertaken. Living, and presumably normal, oysters within the same sample set were also examined. Results indicated that the natural flora of Crassostrea gigas (Thunberg) is composed of organisms representing the genera Pseudomonas, Achromobacter, Flavobacterium, and Vibrio. Pollution indicator organisms such as Escherichia coli were not found. The flora of dead or dying oysters included a somewhat greater incidence of Pseudomonas sp.; a seawater-requiring organism isolated on several occasions from oyster gapers which had been collected from different geographical areas was identified as P. enalia. A description of the organism has been provided, and the characteristics are listed to facilitate identification by other workers encountering the organism in future studies of a similar kind. The seawater requirement exhibited by P. enalia was deduced to be a requirement for sodium chloride for growth of the organism. Experiments to determine the pathogenicity of Pseudomonas enalia were performed by use of experimentally infected animals maintained in aerated seawater tanks. Death of C. gigas occurred when the animal body tissue was injected with viable bacterial cell suspension. Results of histological studies of the normal and infected oyster tissue suggest that bacterial invasion of the tissue occurred. Images Fig. 1 Fig. 2 PMID:6053175

  16. ARSENIC UPTAKE AND LOSS IN THE AMERICAN OYSTER, 'CRASSOSTREA VIRGINIA'

    EPA Science Inventory

    In addition to a control Crassostrea virginica was treated with 3 and 5 micrograms As per kg for 16 wks at ambient seawater salinity and temperature to determine the potential of C. virginica as an indicator of arsenic pollution. Prior to spawning, as much as 10.3 plus or minus 1...

  17. Markers associated with disease resistance in Eastern oysters, Crassostrea virginica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eastern oyster, Crassostrea viginica, is an economically important aquaculture species in the USA, but production has been impacted by diseases such as dermo and MSX. Efforts have been put into the development of disease-resistant oyster lines using selective breeding techniques. However, these met...

  18. Heritability of shell pigmentation in the Pacific oyster, Crassostrea gigas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Pacific oyster (Crassostrea gigas) is a species of considerable economic importance, with among the highest global production of any cultured aquatic animal species. In the interest of increasing the value of Pacific oysters sold as “singles” for the half-shell market, we explored the feasibili...

  19. NATURE AND FUNCTION OF THE BROWN CELL IN CRASSOSTREA VIRGINICA

    EPA Science Inventory

    This study was undertaken to determine the role of the brown cell in Crassostrea virginica in degradative and detoxification processes. istopathological and biochemical methods were used to study brown cells in vivo and in vitro before and after treatment with organic and inorgan...

  20. Intraspecific Variation in Mitogenomes of Five Crassostrea Species Provides Insight into Oyster Diversification and Speciation.

    PubMed

    Ren, Jianfeng; Hou, Zhanhui; Wang, Haiyan; Sun, Ming-An; Liu, Xiao; Liu, Bin; Guo, Ximing

    2016-04-01

    A large number of Crassostrea oysters are found in Asia-Pacific. While analyses of interspecific variation have helped to establish historical relationships among these species, studies on intraspecific variation are necessary to understand their recent evolutionary history and current forces driving population biology. We resequenced 18 and analyzed 31 mitogenomes of five Crassostrea species from China: Crassostrea gigas, Crassostrea angulata, Crassostrea sikamea, Crassostrea ariakensis, and Crassostrea hongkongensis. Our analysis finds abundant insertions, deletions, and single-nucleotide polymorphisms in all species. Intraspecific variation varies greatly among species with polymorphic sites ranging from 54 to 293 and nucleotide diversity ranging from 0.00106 to 0.00683. In all measurements, C. hongkongensis that has the narrowest geographic distribution exhibits the least sequence diversity; C. ariakensis that has the widest distribution shows the highest diversity, and species with intermediate distribution show intermediate levels of diversity. Low sequence diversity in C. hongkongensis may reflect recent bottlenecks that are probably exacerbated by human transplantation. High diversity in C. ariakensis is likely due to divergence of northern and southern China populations that have been separated without gene flow. The significant differences in mitogenome diversity suggest that the five sister species of Crassostrea have experienced different evolutionary forces since their divergence. The recent divergence of two C. ariakensis populations and the C. gigas/angulata species complex provides evidence for continued diversification and speciation of Crassostrea species along China's coast, which are shaped by unknown mechanisms in a north-south divide. PMID:26846524

  1. The effects of electric impulse on growth of Rhizophora mucronata seedlings (Rhizophorales: Rhizophoraceae).

    PubMed

    Kathiresan, K; Rajendran, N

    2000-12-01

    Exposure of mangrove seedlings to electric current was studied at an intensity of 10, 20 and 30 mA to 0.5, 1, 3, 6, 12 and 24 h in different combinations, either to plumule or radicle or both parts of the propagules of Rhizophora mucronata Poir (sample size = 30). The electric current-treated propagules and untreated control were cultured hydroponically in sea water for 75 days, and root and shoot growth parameters measured. The root elongation was significantly influenced by duration of exposure, site of propagule treated and combined effects of current intensity x site of propagule treated. Leaf number and area were significantly influenced by intensity of electric current and duration of exposure; whereas shoot elongation was affected by the duration of exposure. The root number was significantly affected by duration of exposure. In general, the electric impulse improved the growth characteristics of shoot and root. PMID:11487936

  2. A metabolomic investigation of the effects of metal pollution in oysters Crassostrea hongkongensis.

    PubMed

    Ji, Chenglong; Wang, Qing; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2015-01-15

    Metal pollution has been of great concern in the estuaries in Southern China. In this study, metabolic differences between oysters Crassostrea hongkongensis from clean and metal-polluted sites were characterized using NMR-based metabolomics. We collected oyster samples from one clean (Jiuzhen) and two metal polluted sites (Baijiao and Fugong). The metal concentrations in oyster gills indicated that both the Baijiao and Fugong sites were severely polluted by several metals, including Cr, Ni, Cu, Zn, Ag, Cd and Pb. In particular, Cu and Zn were the major contaminants from the Baijiao and Fugong sites. Compared with those oysters from the clean site (JZ), metal pollution in BJ and FG induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways, as indicated by different metabolic biomarkers. This study demonstrates that NMR-based metabolomics is a useful tool for characterizing metabolic responses induced by metal pollution. PMID:25499180

  3. A metabolomic study on the biological effects of metal pollutions in oysters Crassostrea sikamea.

    PubMed

    Ji, Chenglong; Wang, Qing; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2016-01-15

    Metal pollution has become a great threat to organisms in the estuaries in South China. In the present study, the oysters Crassostrea sikamea were collected from one clean (Jiuzhen) and five metal polluted sites (Baijiao, Fugong, Gongqian, Jinshan and Songyu). The tissue metal concentrations in oysters indicated that the five metal sites were polluted by several metals, including Cr, Ni, Co, Cu, Zn, Ag, Cd and Pb with different patterns. Especially, Cu and Zn were the major contaminants in Baijiao, Fugong and Jinshan sites. The metabolic responses in oysters C. sikamea indicated that the metal pollutions in BJ, FG, JS and SY sites induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways. However, the metal pollution in GQ site mainly influenced the osmotic regulation in the oysters C. sikamea. This study demonstrates that NMR-based metabolomics is useful to characterize metabolic responses induced by metal pollution. PMID:26616746

  4. Identification of potential general markers of disease resistance in American oysters, Crassostrea virginica through gene expression studies.

    PubMed

    Nikapitiya, Chamilani; McDowell, Ian C; Villamil, Luisa; Muñoz, Pilar; Sohn, SaeBom; Gomez-Chiarri, Marta

    2014-11-01

    Several diseases have a significant impact on American oyster populations in the Atlantic coasts of North America. Knowledge about the responses of oysters to pathogenic challenge could help in identifying potential markers of disease resistance and biomarkers of the health status of an oyster population. A previous analysis of the transcriptome of resistant and susceptible American oysters in response to challenge with the bacterial pathogen Roseovarius crassostreae, as well as sequencing of suppression subtractive hybridization libraries from oysters challenged with the protozoan parasite Perkinsus marinus, provided a list of genes potentially involved in disease resistance or susceptibility. We investigated the patterns of inducible gene expression of several of these genes in response to experimental challenge with the oyster pathogens R. crassostreae, Vibrio tubiashii, and P. marinus. Oysters showing differential susceptibility to R. crassostreae demonstrated differential patterns of expression of genes coding for immune (serine protease inhibitor-1, SPI1) and stress-related (heat shock protein 70, HSP70; arginine kinase) proteins 30 days after challenge with this bacterial pathogen. Differential patterns of expression of immune (spi1, galectin and a matrix metalloproteinase) and stress-related (hsp70, histone H4, and arginine kinase) genes was observed in hemocytes from adult oysters challenged with P. marinus, but not with V. tubiashii. While levels of spi1 expression in hemocytes collected 8 and 21 days after P. marinus challenge were negatively correlated with parasite load in oysters tissues at the end of the challenge (62 days), levels of expression of hsp70 in hemocytes collected 1-day after challenge were positively correlated with oyster parasite load at 62 days. Our results confirm previous research on the role of serine protease inhibitor-1 in immunity and disease resistance in oysters. They also suggest that HSP70 and histone H4 could be used

  5. Electron density of Rhizophora spp. wood using Compton scattering technique at 15.77, 17.48 and 22.16 keV XRF energies

    NASA Astrophysics Data System (ADS)

    Shakhreet, B. Z.; Bauk, S.; Shukri, A.

    2015-02-01

    Compton (incoherently) scattered photons which are directly proportional to the electron density of the scatterer, have been employed in characterizing Rhizophora spp. as breast tissue equivalent. X-ray fluorescent scattered incoherently from Rhizophora spp. sample was measured using Si-PIN detector and three XRF energy values 15.77, 17.48 and 22.16 keV. This study is aimed at providing electron density information in support of the introduction of new tissue substitute materials for mammography phantoms.

  6. Applications of Multiple Nuclear Genes to the Molecular Phylogeny, Population Genetics and Hybrid Identification in the Mangrove Genus Rhizophora.

    PubMed

    Chen, Yongmei; Hou, Yansong; Guo, Zixiao; Wang, Wenqing; Zhong, Cairong; Zhou, Renchao; Shi, Suhua

    2015-01-01

    The genus Rhizophora is one of the most important components of mangrove forests. It is an ideal system for studying biogeography, molecular evolution, population genetics, hybridization and conservation genetics of mangroves. However, there are no sufficient molecular markers to address these topics. Here, we developed 77 pairs of nuclear gene primers, which showed successful PCR amplifications across all five Rhizophora species and sequencing in R. apiculata. Here, we present three tentative applications using a subset of the developed nuclear genes to (I) reconstruct the phylogeny, (II) examine the genetic structure and (III) identify natural hybridization in Rhizophora. Phylogenetic analyses support the hypothesis that Rhizophora had disappeared in the Atlantic-East Pacific (AEP) region and was re-colonized from the IWP region approximately 12.7 Mya. Population genetics analyses in four natural populations of R. apiculata in Hainan, China, revealed extremely low genetic diversity, strong population differentiation and extensive admixture, suggesting that the Pleistocene glaciations, particularly the last glacial maximum, greatly influenced the population dynamics of R. apiculata in Hainan. We also verified the hybrid status of a morphologically intermediate individual between R. apiculata and R. stylosa in Hainan. Based on the sequences of five nuclear genes and one chloroplast intergenic spacer, this individual is likely to be an F1 hybrid, with R. stylosa as its maternal parent. The nuclear gene markers developed in this study should be of great value for characterizing the hybridization and introgression patterns in other cases of this genus and testing the role of natural selection using population genomics approaches. PMID:26674070

  7. Applications of Multiple Nuclear Genes to the Molecular Phylogeny, Population Genetics and Hybrid Identification in the Mangrove Genus Rhizophora

    PubMed Central

    Chen, Yongmei; Hou, Yansong; Guo, Zixiao; Wang, Wenqing; Zhong, Cairong; Zhou, Renchao; Shi, Suhua

    2015-01-01

    The genus Rhizophora is one of the most important components of mangrove forests. It is an ideal system for studying biogeography, molecular evolution, population genetics, hybridization and conservation genetics of mangroves. However, there are no sufficient molecular markers to address these topics. Here, we developed 77 pairs of nuclear gene primers, which showed successful PCR amplifications across all five Rhizophora species and sequencing in R. apiculata. Here, we present three tentative applications using a subset of the developed nuclear genes to (I) reconstruct the phylogeny, (II) examine the genetic structure and (III) identify natural hybridization in Rhizophora. Phylogenetic analyses support the hypothesis that Rhizophora had disappeared in the Atlantic-East Pacific (AEP) region and was re-colonized from the IWP region approximately 12.7 Mya. Population genetics analyses in four natural populations of R. apiculata in Hainan, China, revealed extremely low genetic diversity, strong population differentiation and extensive admixture, suggesting that the Pleistocene glaciations, particularly the last glacial maximum, greatly influenced the population dynamics of R. apiculata in Hainan. We also verified the hybrid status of a morphologically intermediate individual between R. apiculata and R. stylosa in Hainan. Based on the sequences of five nuclear genes and one chloroplast intergenic spacer, this individual is likely to be an F1 hybrid, with R. stylosa as its maternal parent. The nuclear gene markers developed in this study should be of great value for characterizing the hybridization and introgression patterns in other cases of this genus and testing the role of natural selection using population genomics approaches. PMID:26674070

  8. Immunological responses of the mangrove oysters Crassostrea gasar naturally infected by Perkinsus sp. in the Mamanguape Estuary, Paraíba state (Northeastern, Brazil).

    PubMed

    Queiroga, Fernando Ramos; Marques-Santos, Luis Fernando; Hégaret, Hélène; Soudant, Philippe; Farias, Natanael Dantas; Schlindwein, Aline Daiane; Mirella da Silva, Patricia

    2013-08-01

    Perkinsus genus includes protozoan parasites of marine mollusks, especially bivalves. In the last four years, this parasite has been detected in mangrove oysters Crassostrea rhizophorae and Crassostrea gasar from the Northeastern region of Brazil. Hemocytes are the key cells of the oyster immune system, being responsible for a variety of cellular and humoral reactions, such as phagocytosis, encapsulation and the release of several effector molecules that control the invasion and proliferation of microorganisms. In Brazil, there is little information on perkinsosis and none on the immune responses of native oysters' species against Perkinsus spp. The objective of this study was to determine the effects of natural infection by Perkinsus sp. on the immunological parameters of mangrove oysters C. gasar cultured in the Mamanguape River Estuary (Paraíba, Brazil). Adults oysters (N = 40/month) were sampled in December 2011, March, May, August and October 2012. Gills were removed and used to determine the presence and intensity of the Perkinsus sp. infection, according to a scale of four levels (1-4), using the Ray's fluid thioglycollate medium assay. Immunological parameters were measured in hemolymph samples by flow cytometry, including: total hemocyte count (THC), differential hemocyte count (DHC), cell mortality, phagocytic capacity, and production of Reactive Oxygen Species (ROS). The plasma was used to determine the hemagglutination activity. The results showed the occurrence of Perkinsus sp. with the highest mean prevalence (93.3%) seen so far in oyster populations in Brazil. Despite that, no oyster mortality was associated. In contrast, we observed an increase in hemocyte mortality and a suppression of two of the main defense mechanisms, phagocytosis and ROS production in infected oysters. The increase in the percentage of blast-like cells on the hemolymph, and the increase in THC in oysters heavily infected (at the maximum intensity, 4) suggest an induction of

  9. A PCR-based diagnostic assay for the detection of Roseovarius crassostreae in Crassostrea virginica affected by juvenile oyster disease (JOD)

    USGS Publications Warehouse

    Maloy, A.P.; Barber, B.J.; Boettcher, K.J.

    2005-01-01

    We have developed a PCR-assay for the diagnosis of juvenile oyster disease (JOD) based on the detection of Roseovarius crassostreae directly from affected oysters. Species-specific primers are used to amplify the 16S-23S rDNA internal transcribed spacer (ITS) of R. crassostreae, and confirmation of product identity is accomplished by restriction enzyme analysis. No false positives were obtained with either closely related bacterial species or from other DNAs present in oyster samples. The assay has the potential to detect as few as 10 cells of R. crassostreae per oyster when samples are taken from the inner valve surfaces of the animal. Inclusion of material from soft body surfaces is not necessary, and may reduce sensitivity approximately 10-fold. In a JOD-affected population, a positive PCR result was obtained from all oysters from which these bacteria were subsequently cultured. The assay also detected the presence of R. crassostreae in 2 oysters from which no R. crassostreae isolates were recovered. No R. crassostreae was detected by either PCR or bacteriology in oysters from a population that was not exhibiting JOD-signs. This assay is expected to advance regional disease management efforts and provide valuable insights into the disease process and epizootiology of JOD. ?? Inter-Research 2005.

  10. [Abundance and richness of mollusks and crustaceans associated to the submerged roots of red mangrove (Rhizophora mangle) at Bocaripo Lagoon, Sucre, Venezuela].

    PubMed

    Cedeño, Jennellis; Jiménez Prieto, Mayré; Pereda, Luisana; Allen, Thays

    2010-10-01

    Mangrove roots are important habitats for many species. The abundance and richness of mollusks and crustaceans associated with the roots demerged of Rhizophora mangle was studied. The samples were gathered between February 2005 and January 2006, in Bocaripo lagoon, north coast of Sucre state, Venezuela. Five stations were established inside the lagoon; on every station two roots were chosen at random, put in plastic bags and scraped. The associated organisms were separated by taxa and fixed in 10% formaldehyde. One thousand ninety two specimens of mollusks, distributed in two classes: Bivalve and Gastropod were collected. Bivalve was the most abundant with 943 individuals. The most representative family was Mytilidae with 6 species, being Musculus lateralis the dominant species. The crustaceans were represented by 372 organisms, belonging to the class Malacostraca, where Panopeus herbstii (169 ind.) was the most abundant species. The families Panopeidae, Porcellanidae and Majidae had the highest number of species. Maximum abundance was in February (224 ind.), with a richness of 25 species and the minimums in November (45 ind.) and a richness of 12 species. The stations 1 and 5 presented the major abundance and richness of organisms, which could be related to environmental conditions favorable, as the major availability of microhabitats and nourishing offer; on the contrary the station 4, presented a more inhospitable environment, due to the high values in the salinity and temperature, which contributes with the minor abundance and richness of the present species. PMID:21302531

  11. Chemical ecology of red mangroves, Rhizophora mangle, in the Hawaiian Islands

    USGS Publications Warehouse

    Fry, Brian; Cormier, Nicole

    2011-01-01

    The coastal red mangrove, Rhizophora mangle L., was introduced to the Hawaiian Islands from Florida 100 yr ago and has spread to cover many shallow intertidal shorelines that once were unvegetated mudflats. We used a field survey approach to test whether mangroves at the land-ocean interface could indicate watershed inputs, especially whether measurements of leaf chemistry could identify coasts with high nutrient inputs and high mangrove productivities. During 2001-2002, we sampled mangroves on dry leeward coasts of southern Moloka'i and O'ahu for 14 leaf variables including stable carbon and nitrogen isotopes (delta13C, delta15N), macronutrients (C, N, P), trace elements (B, Mn, Fe, Cu, Zn), and cations (Na, Mg, K, Ca). A new modeling approach using leaf Na, N, P, and delta13C indicated two times higher productivity for mangroves in urban versus rural settings, with rural mangroves more limited by low N and P nutrients and high-nutrient urban mangroves more limited by freshwater inputs and salt stress. Leaf chemistry also helped identify other aspects of mangrove dynamics: especially leaf delta15N values helped identify groundwater N inputs, and a combination of strongly correlated variables (C, N, P, B, Cu, Mg, K, Ca) tracked the mangrove growth response to nutrient loading. Overall, the chemical marker approach is an efficient way to survey watershed forcing of mangrove forest dynamics.

  12. The complete mitochondrial genome of Crassostrea gasar (Bivalvia: Ostreidae).

    PubMed

    Cavaleiro, Nathalia P; Solé-Cava, Antonio M; Melo, Cláudio M R; de Almeida, Luiz G; Lazoski, Cristiano; Vasconcelos, Ana Tereza R

    2016-07-01

    The complete mitochondrial genome of Crassostrea gasar was sequenced using the Ion Proton technology in combination with 454 Roche GS-FLX plataform data. We assembled a 17,686 bp complete circular mitochondrial genome, containing 13 protein-coding genes, a major non-coding region (MNR), two ribosomal RNA genes and 24 transfer RNA genes. Phylogenetic analysis of concatenated amino acid sequences from mitochondria showed monophyletic clades formed with high bootstrap values. This is the first complete mitochondrial sequence of an oyster from South America. Mitogenome sequence was deposited in GenBank under the accession number KR856227. PMID:27158791

  13. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    SciTech Connect

    Yusof, Mohd Fahmi Mohd Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz; Bauk, Sabar; Hashim, Rokiah

    2015-04-29

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

  14. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    NASA Astrophysics Data System (ADS)

    Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

    2015-04-01

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ2 value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ2 value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

  15. Interspecific hybridization between Crassostrea angulata and C. ariakensis

    NASA Astrophysics Data System (ADS)

    Yao, Tuo; Zhang, Yuehuan; Yan, Xiwu; Wang, Zhaoping; Li, Dongchun; Su, Jiaqi; Yu, Ruihai

    2015-08-01

    Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀ × C. ariakensis ♂ was lower than that of C. ariakensis ♀ × C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ × C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀ × C. ariakensis ♂ and C. ariakensis ♀ × C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.

  16. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 - 25.26 keV photon energy range

    NASA Astrophysics Data System (ADS)

    Mohd Yusof, Mohd Fahmi; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

    2015-04-01

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941).

  17. HISTOPATHOLOGY AND BIOACCUMULATION IN OYSTERS CRASSOSTREA VIRGINICA LIVING ON WOOD PRESERVED WITH CHROMATED COPPER ARSENATE

    EPA Science Inventory

    Oysters (Crassostrea virginica) growing on wood treated with chromated cooper arsenate (CCA) have elevated levels of metals, especially copper. oysters living inside a residential canal lined with CCA wood bulkheads were often green and had high copper concentrations. hese oyster...

  18. IN VITRO KILLING OF PERKINSUS MARINUS BY HEMOCYTES OF OYSTERS CRASSOSTREA VIRGINICA

    EPA Science Inventory

    A colorimetric microbicidal assay was adapted, optimized and applied in experiments to characterize the in vitro capacity of eastern oyster (Crassostrea virginica) hemocytes to kill cultured isolates of Perkinsus marinus, a protozoan parasite causing a highly destructive disease...

  19. RESPONSES OF OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTES TO NONPATHOGENIC AND CLINICAL ISOLATES OF VIBRIO PARAHAEMOLYTICUS

    EPA Science Inventory

    Bacterial uptake by oysters (Crassostrea virginica) and bactericidal activity of oyster hemocytes were studied using four environmental isolates and three clinical isolates of Vibrio parahaemolyticus. Clinical isolates (2030, 2062, 2107) were obtained from gastroenteritis patien...

  20. WATER QUALITY AND OYSTER HEALTH (CRASSOSTREA VIRGINICA): AN INTEGRATED APPROACH TO DETERMINING HABITAT RESTORATION POTENTIAL

    EPA Science Inventory

    Volety, Aswani K., S. Gregory Tolley and James T. Winstead. 2001. Water Quality and Oyster Health (Crassostrea virginica): An Integrated Approach to Determining Habitat Restoration Potential (Abstract). Presented at the 5th International Conference on Shellfish Restoration, 18-21...

  1. Influence of a Salinity Gradient on the Vessel Characters of the Mangrove Species Rhizophora mucronata

    PubMed Central

    SCHMITZ, NELE; VERHEYDEN, ANOUK; BEECKMAN, HANS; KAIRO, JAMES GITUNDU; KOEDAM, NICO

    2006-01-01

    • Background and Aims Although mangroves have been extensively studied, little is known about their ecological wood anatomy. This investigation examined the potential use of vessel density as a proxy for soil water salinity in the mangrove species Rhizophora mucronata (Rhizophoraceae) from Kenya. • Methods In a time-standardized approach, 50 wood discs from trees growing in six salinity categories were investigated. Vessel densities, and tangential and radial diameters of rainy and dry season wood of one distinct year, at three positions on the stem discs, were measured. A repeated-measures ANOVA with the prevailing salinity was performed. • Key Results Vessel density showed a significant increase with salinity, supporting its use as a prospective measure of salinity. Interestingly, the negative salinity response of the radial diameter of vessels was less striking, and tangential diameter was constant under the varying environmental conditions. An effect of age or growth rate or the presence of vessel dimorphism could be excluded as the cause of the absence of any ecological trend. • Conclusions The clear trend in vessel density with salinity, together with the absence of a growth rate and age effect, validates the potential of vessel density as an environmental proxy. However, it can only be used as a relative measure of salinity given that other environmental variables such as inundation frequency have an additional influence on vessel density. With view to a reliable, absolute proxy, future research should focus on finding wood anatomical features correlated exclusively with soil water salinity or inundation frequency. The plasticity in vessel density with differing salinity suggests a role in the establishment of a safe water transport system. To confirm this hypothesis, the role of inter-vessel pits, their relationship to the rather constant vessel diameter and the underlying physiology and cell biology needs to be examined. PMID:17062590

  2. Influence of salinity on hydrogen isotope fractionation in Rhizophora mangroves from Micronesia

    NASA Astrophysics Data System (ADS)

    Ladd, S. Nemiah; Sachs, Julian P.

    2015-11-01

    Hydrogen isotope ratios (2H/1H or δ2H) of plant leaf waxes typically covary with those of precipitation, and are therefore used as a proxy for past hydrologic variability. Mangroves present an important exception to this relationship, as salinity can strongly influence 2H fractionation in leaf lipids. To better understand and calibrate this effect, δ2H values of taraxerol and n-alkanes were measured in the leaves of Rhizophora spp. (red mangroves) from three estuaries and four brackish lakes on the Micronesian islands of Pohnpei and Palau, and compared to the δ2H and δ18O values of leaf water, xylem water and surface water. Net 2H discrimination between surface water and taraxerol increased by 0.9 ± 0.2‰ per part per thousand (ppt-1) over a salinity range of 1-34 ppt. Xylem water was always depleted in 2H relative to surface water, and the magnitude of this depletion increased with salinity, which is most likely due to a combination of greater 2H discrimination by roots during water uptake and opportunistic use of freshwater. Changes in the 2H content of xylem water can account for up to 43% of the change in net taraxerol fractionation with salinity. Leaf water isotopes were minimally enriched relative to xylem water and there was not significant variability in leaf water enrichment with salinity, which is consistent with a Péclet-modified Craig-Gordon model of leaf water enrichment. As leaf water enrichment is therefore unlikely to be responsible for increased 2H/1H fractionation in mangrove leaf lipids at elevated salinities, the majority of this signal is most likely explained either by changes in biosynthetic fractionation in response to salt stress or by salinity influenced changes in the timing of water uptake and lipid synthesis.

  3. Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice

    PubMed Central

    Deivanai, Subramanian; Bindusara, Amitraghata Santhanam; Prabhakaran, Guruswamy; Bhore, Subhash Janardhan

    2014-01-01

    Background: Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. Objective: The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. Materials and Methods: Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. Results: The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. Conclusion: These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria. PMID

  4. Antiradical and antidiabetic properties of standardized extract of Sunderban mangrove Rhizophora mucronata

    PubMed Central

    Sur, Tapas Kumar; Hazra, Alok Kumar; Bhattacharyya, Dipankar; Hazra, Avijit

    2015-01-01

    Background: Mangroves have the ability to grow where no other vascular plants survive. Rhizophora mucronata is a true mangrove and traditionally used to treat diabetes and its allied complications. Objectives: In the present study, we standardized the 80% methanolic standardized extract of R. mucronata leaves (RH) and found out its antiradical and antidiabetic activities. Materials and Methods: The methanolic extract of R. mucronata leaves (RH) was standardized and quantified for phenolics, flavonoinds, gallic acid, quercetin, and coumarin. The reducing abilities and antiradical activities of RH were performed in vitro methods like, 1,1-diphenyl-2-picrylhydrazyl, nitric oxides, superoxides, hydroxyl, and ABTS (2,2’-azino-bis-3-ethyl benzthiazoline-6-sulphonic acid). Thereafter, RH was evaluated for it antidiabetic potentialities on streptozotocin (STZ)-induced type-2 diabetes. STZ (90 mg/kg, intraperitoneal) was administered to 2 days old pups to induce diabetes. RH was fed at doses of 50 and 100 mg/kg and glibenclamide (positive control) at 5 mg/kg, when the rats were 6 weeks old and continued for 10 weeks. Fasting glucose was monitored before and after the treatment. Further, lipid peroxides and reduced glutathione level were estimated on rat liver. Results: The results obtained from this study revealed RH possesses flavonoinds and also gallic acid, quercetin, and coumarin. Further, it has antiradical activities. It has also reduced blood glucose level in type-2 diabetic rats and reduced the formation of lipid peroxidation in liver. RH enhanced the level of glutathione in liver tissue. Conclusion: RH exhibits source of natural antioxidants and great potentialities as an antidiabetic agent by improving the hyperglycemia through its antiradical action. PMID:25829780

  5. Landscape characteristics of Rhizophora mangle forests and propagule deposition in coastal environments of Florida (USA)

    USGS Publications Warehouse

    Sengupta, R.; Middleton, B.; Yan, C.; Zuro, M.; Hartman, H.

    2005-01-01

    Field dispersal studies are seldom conducted at regional scales even though reliable information on mid-range dispersal distance is essential for models of colonization. The purpose of this study was to examine the potential distance of dispersal of Rhizophora mangle propagules by comparing deposition density with landscape characteristics of mangrove forests. Propagule density was estimated at various distances to mangrove sources (R. mangle) on beaches in southwestern Florida in both high-and low-energy environments, either facing open gulf waters vs. sheltered, respectively. Remote sensing and Geographic Information Systems were used to identify source forests and to determine their landscape characteristics (forest size and distance to deposition area) for the regression analyses. Our results indicated that increasing density of propagules stranded on beaches was related negatively to the distance of the deposition sites from the nearest stands of R. mangle and that deposition was greatly diminished 2 km or more from the source. Measures of fragmentation such as the area of the R. mangle forests were related to propagule deposition but only in low-energy environments. Our results suggest that geographic models involving the colonization of coastal mangrove systems should include dispersal dynamics at mid-range scales, i.e., for our purposes here, beyond the local scale of the forest and up to 5 km distant. Studies of mangrove propagule deposition at various spatial scales are key to understanding regeneration limitations in natural gaps and restoration areas. Therefore, our study of mid-range propagule dispersal has broad application to plant ecology, restoration, and modeling. ?? Springer 2005.

  6. Proteomic characterization of mucosal secretions in the eastern oyster, Crassostrea virginica.

    PubMed

    Pales Espinosa, Emmanuelle; Koller, Antonius; Allam, Bassem

    2016-01-30

    The soft body surface of marine invertebrates is covered by a layer of mucus, a slippery gel secreted by mucocytes lining epithelia. The functions of this gel are diverse including locomotion, cleansing, food particles processing and defense against physicochemical injuries and infectious agents. In oysters, mucus covering pallial organs has been demonstrated to have a major importance in the processing of food particles and in the interactions with waterborne pathogens. Given the limited information available on mucus in bivalves and the apparent wide spectra of activity of bioactive molecules present in this matrix, the characterization of these mucosal secretions has become a research priority. In this study, mucus was separately collected from the mantle, gills and labial palps of the eastern oyster (Crassostrea virginica) and analyzed by liquid chromatography and tandem mass spectrometry. Results showed the presence of a wide variety of molecules involved in host-microbe interactions, including putative adhesion molecules (e.g. c-type lectins) confirming that transcripts previously identified in epithelial cells are translated into proteins secreted in mucus. Mucus composition was different among samples collected from different organs. These results generate a reference map for C. virginica pallial mucus to better characterize the various physiological functions of mucosal secretions. PMID:26612663

  7. Complete mitochondrial DNA sequence of oyster Crassostrea hongkongensis-a case of "Tandem duplication-random loss" for genome rearrangement in Crassostrea?

    PubMed Central

    Yu, Ziniu; Wei, Zhengpeng; Kong, Xiaoyu; Shi, Wei

    2008-01-01

    Background Mitochondrial DNA sequences are extensively used as genetic markers not only for studies of population or ecological genetics, but also for phylogenetic and evolutionary analyses. Complete mt-sequences can reveal information about gene order and its variation, as well as gene and genome evolution when sequences from multiple phyla are compared. Mitochondrial gene order is highly variable among mollusks, with bivalves exhibiting the most variability. Of the 41 complete mt genomes sequenced so far, 12 are from bivalves. We determined, in the current study, the complete mitochondrial DNA sequence of Crassostrea hongkongensis. We present here an analysis of features of its gene content and genome organization in comparison with two other Crassostrea species to assess the variation within bivalves and among main groups of mollusks. Results The complete mitochondrial genome of C. hongkongensis was determined using long PCR and a primer walking sequencing strategy with genus-specific primers. The genome is 16,475 bp in length and contains 12 protein-coding genes (the atp8 gene is missing, as in most bivalves), 22 transfer tRNA genes (including a suppressor tRNA gene), and 2 ribosomal RNA genes, all of which appear to be transcribed from the same strand. A striking finding of this study is that a DNA segment containing four tRNA genes (trnk1, trnC, trnQ1 and trnN) and two duplicated or split rRNA gene (rrnL5' and rrnS) are absent from the genome, when compared with that of two other extant Crassostrea species, which is very likely a consequence of loss of a single genomic region present in ancestor of C. hongkongensis. It indicates this region seem to be a "hot spot" of genomic rearrangements over the Crassostrea mt-genomes. The arrangement of protein-coding genes in C. hongkongensis is identical to that of Crassostrea gigas and Crassostrea virginica, but higher amino acid sequence identities are shared between C. hongkongensis and C. gigas than between other

  8. Biological responses of the american oyster 'Crassostrea virginica' (gmelin) to thermal effluent in the Chesapeake-Delaware Bay area. Final report

    SciTech Connect

    Tinsman, J.C.; Maurer, D.; Pennachi, K.A.

    1981-01-01

    This report presents the results of a 1979 study of various aspects of the life history of the oyster, Crassostrea virginica, and the effects of temperature-salinity interactions in the mid-Atlantic region. The study was intended to provide input to power plant siting decisions in the Chesapeake Bay area. Eighteen collections of planted oysters were made from effluent and control stations of two power plant sites in the mid-Atlantic region. Oyster mortalities were related to physical extremes at both sites, but were higher at PEPCO. Shell growth was evident at DPL, but not at PEPCO.

  9. Mercury in cultured oysters (Crassostrea gigas Thunberg, 1793 and C. corteziensis Hertlein, 1951) from four coastal lagoons of the SE Gulf of California, Mexico.

    PubMed

    Osuna-Martínez, C C; Páez-Osuna, F; Alonso-Rodríguez, R

    2010-09-01

    In order to determine the mercury concentrations in cultured oysters from coastal lagoons (SE Gulf of California), several individuals of Crassostrea gigas and C. corteziensis were collected and their mercury levels were measured with a cold vapor analyzer. The mean concentrations during the rainy and dry seasons, respectively, were 0.70 and 0.15 microg g(-1) in C. gigas and 0.56 and 0.18 microg g(-1) in C. corteziensis. During the rainy season, elevated mercury contents are apparently related to terrigen transport from the watershed, while during the dry season, the moderate levels are related to upwellings. PMID:20697884

  10. Perkinsus marinus in Crassostrea gigas in the Gulf of California.

    PubMed

    Enríquez-Espinoza, T L; Grijalva-Chon, J M; Castro-Longoria, R; Ramos-Paredes, J

    2010-04-01

    To determine the agent responsible for the massive mortalities of the Pacific oyster Crassostrea gigas in northwest Mexico, 30 oysters were sampled after a severe mortality event in 2006 along the Sonoran coast. Histological analyses revealed the presence of a protozoan and Ray's fluid thioglycollate medium (RFTM) assays showed the presence of Perkinsus sp., identified as P. marinus from the DNA sequence of the internal transcribed spacer (ITS) of the ribosomal RNA (rRNA) gene complex. PCR analyses for Marteilia refringens, M. sydneyi, and Haplosporidium costale were negative. P. marinus presence in the Pacific oyster may be responsible for massive mortalities of the oyster, along with other environmental factors in the Gulf of California. PMID:20481094

  11. Adult Pacific Oyster (Crassostrea gigas) May Have Light Sensitivity

    PubMed Central

    Yang, Yanjian; Li, Zhuang; Guo, Ting; Li, Yongchuan; Wang, Xiaotong

    2015-01-01

    Light-sensitivity is an important aspect of mollusk survival as it plays a vital role in reproduction and predator avoidance. In the Pacific oyster Crassostrea gigas light sensitivity has been demonstrated in the larval stage but has not yet been conclusively demonstrated in adult oysters. In this paper we describe an experiment which was undertaken to determine if adult Pacific oysters were sensitive to light. One LED flashlight was used to shine light onto adult oysters while they were filtering seawater through their shell openings. We found that the degree of opening increased gradually during the light period but rapidly decreased when the flashlight was turned off in the treated group but not in the control group. These results suggest that adult Pacific oyster may be sensitive to light. PMID:26474058

  12. Preparation and antioxidant activities of oligosaccharides from Crassostrea gigas.

    PubMed

    Wu, Shengjun; Huang, Xiaolian

    2017-02-01

    Oligosaccharides were prepared from Crassostrea gigas by hydrolysis of polysaccharide in C. gigas with peroxide oxygen (H2O2). The hydrolysates were cleared of protein, filtered, ultrafiltered and precipitated with absolute ethanol to give C. gigas oligosaccharides (CGOs). Factors affecting CGO yields, i.e., reaction time, temperature, and H2O2 concentration, were optimised as follows: 2.96h reaction time, 84.71°C reaction temperature, and 2.46% H2O2 concentration. Under these conditions, the maximum yield of CGOs reached 10.61%. The CGOs were then partially characterised by Fourier transform infrared spectroscopy, UV spectroscopy, monosaccharide composition, and antioxidant activities. Results indicate that CGOs possessed strong hydroxyl radical activity, 2,2-diphenyl-β-picrylhydrazyl-radical-scavenging activity and reducing capacity at a concentration of 100μg/mL. PMID:27596415

  13. Utilization of detrital complexes by the oyster, Crassostrea virginica (Gmelin)

    SciTech Connect

    Crosby, M.P.

    1987-01-01

    The contribution of bacteria and nonliving particulate organic matter of detrital complexes to the nutrition of the American oyster, Crassostrea virginica, was investigated in the laboratory under normal feeding conditions. Results indicate the oysters were capable of assimilating crude fiber extracted from /sup 14/C-Spartina alterniflora with an efficiency of approximately 3% and that enteric bacteria did not enhance this process. Less than 1% of an oyster's energetic demands could be met by direct utilization of this substrate, in the Choptank River subestuary of the Chesapeake Bay. The potential contribution of refractory organics to oysters in large salt marshes having crude fiber concentration greater than in the Choptank system, are discussed. The ability of the oyster to utilize /sup 14/C and /sup 15/N from cellulolytic marine bacteria, isolated from a S. alterniflora dominated salt marsh, was also studied.

  14. Parasites infecting the cultured oyster Crassostrea gasar (Adanson, 1757) in Northeast Brazil.

    PubMed

    Queiroga, Fernando Ramos; Vianna, Rogério Tubino; Vieira, Cairé Barreto; Farias, Natanael Dantas; Da Silva, Patricia Mirella

    2015-05-01

    The oyster Crassostrea gasar is a species widely used as food and a source of income for the local population of the estuaries of Northeast Brazil. Perkinsus marinus and Perkinsus olseni are deleterious parasites for oyster farming and were recently detected in Brazil. In this study, a histopathologic survey of the oyster C. gasar cultured in the estuary of the River Mamanguape (Paraíba State) was performed. Adult oysters were collected in December 2011 and March, May, August and October 2012 and processed for histology and Perkinsus sp. identification by molecular analyses. Histopathological analysis revealed the presence of parasitic organisms including viral gametocytic hypertrophy, prokaryote-like colonies, protozoans (Perkinsus sp. and Nematopsis sp.) and metazoans (Tylocephalum sp. and cestodes). Other commensal organisms were also detected (the protozoan Ancistrocoma sp. and the turbellarian Urastoma sp.). The protozoan parasite Perkinsus sp. had the highest overall prevalence among the symbiotic organisms studied (48.9%), followed by Nematopsis sp. (36.3%). The other organisms were only sporadically observed. Only the protozoan Perkinsus sp. caused alterations in the oysters' infected organs. Molecular analyses confirmed the presence of P. marinus, P. olseni and Perkinsus beihaiensis infecting the oyster C. gasar. This is the first report of P. beihaiensis in this oyster species. PMID:25553815

  15. Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

    PubMed Central

    King, Gary M.; Judd, Craig; Kuske, Cheryl R.; Smith, Conor

    2012-01-01

    We used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strain dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. A comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish. PMID:23251548

  16. A Genetic Discontinuity in a Continuously Distributed Species: Mitochondrial DNA in the American Oyster, Crassostrea Virginica

    PubMed Central

    Reeb, C. A.; Avise, J. C.

    1990-01-01

    Restriction site variation in mitochondrial DNA (mtDNA) of the American oyster (Crassostrea virginica) was surveyed in continuously distributed populations sampled from the Gulf of St. Lawrence, Canada, to Brownsville, Texas. mtDNA clonal diversity was high, with 82 different haplotypes revealed among 212 oysters with 13 endonucleases. The mtDNA clones grouped into two distinct genetic arrays (estimated to differ by about 2.6% in nucleotide sequence) that characterized oysters collected north vs. south of a region on the Atlantic mid-coast of Florida. The population genetic ``break'' in mtDNA contrasts with previous reports of near uniformity of nuclear (allozyme) allele frequencies throughout the range of the species, but agrees closely with the magnitude and pattern of mtDNA differentiation reported in other estuarine species in the southeastern United States. This concordance of mtDNA phylogenetic pattern across independently evolving species provides strong evidence for vicariant biogeographic processes in initiating intraspecific population structure. The post-Miocene ecological history of the region suggests that reduced precipitation levels in an enlarged Floridian peninsula may have created discontinuities in suitable estuarine habitat for oysters during glacial periods, and that today such population separations are maintained by the combined influence of ecological gradients and oceanic currents on larval dispersal. The results are consistent with the hypothesis that historical vicariant events, in conjunction with contemporary environmental influences on gene flow, can result in genetic discontinuities in continuously distributed species with high dispersal capability. PMID:1968412

  17. Reef-Specific Patterns of Gene Expression Plasticity in Eastern Oysters (Crassostrea virginica).

    PubMed

    Eierman, Laura E; Hare, Matthew P

    2016-01-01

    Understanding the interaction between phenotypic plasticity and evolutionary processes is important for predicting a species' response to changing environment. Strong recurrent selection each generation may be an important process in highly fecund species with broad dispersal and extensive early mortality. We tested whether selection was associated with spatial divergence in gene expression plasticity for osmoregulation in the eastern oyster (Crassostrea virginica). We collected adult oysters from high and low salinity reefs within a single estuary and after 9 weeks of acclimation at 10 and 30 salinity, measured gene expression in 24 oysters using next-generation RNA sequencing technology. The oysters had significantly different expression (DE) in response to salinity treatments for 7936 (18.9%) transcripts overall, with planned contrasts showing 8× more DE in oysters from the high-salinity reef and 15× more DE between reefs when tested at 10 salinity. The reef-by-treatment interaction was also genomically pervasive (5858 DE transcripts, 13.9%). Inter-reef F ST for transcript SNPs averaged 0.0025 with the top 1% between 0.29 and 0.73. Transcripts containing "outlier" SNPs were significantly enriched for osmoregulatory genes and showed patterns of variation consistent with selection on the low-salinity reef. Both phenotypic plasticity and recurrent selection seem to be important factors determining the realized niche of oysters within estuaries. PMID:26245921

  18. A glutamic acid decarboxylase (CgGAD) highly expressed in hemocytes of Pacific oyster Crassostrea gigas.

    PubMed

    Li, Meijia; Wang, Lingling; Qiu, Limei; Wang, Weilin; Xin, Lusheng; Xu, Jiachao; Wang, Hao; Song, Linsheng

    2016-10-01

    Glutamic acid decarboxylase (GAD), a rate-limiting enzyme to catalyze the reaction converting the excitatory neurotransmitter glutamate to inhibitory neurotransmitter γ-aminobutyric acid (GABA), not only functions in nervous system, but also plays important roles in immunomodulation in vertebrates. However, GAD has rarely been reported in invertebrates, and never in molluscs. In the present study, one GAD homologue (designed as CgGAD) was identified from Pacific oyster Crassostrea gigas. The full length cDNA of CgGAD was 1689 bp encoding a polypeptide of 562 amino acids containing a conserved pyridoxal-dependent decarboxylase domain. CgGAD mRNA and protein could be detected in ganglion and hemocytes of oysters, and their abundance in hemocytes was unexpectedly much higher than those in ganglion. More importantly, CgGAD was mostly located in those granulocytes without phagocytic capacity in oysters, and could dynamically respond to LPS stimulation. Further, after being transfected into HEK293 cells, CgGAD could promote the production of GABA. Collectively, these findings suggested that CgGAD, as a GABA synthase and molecular marker of GABAergic system, was mainly distributed in hemocytes and ganglion and involved in neuroendocrine-immune regulation network in oysters, which also provided a novel insight to the co-evolution between nervous system and immune system. PMID:27208883

  19. Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

    DOE PAGESBeta

    King, Gary M.; Judd, Craig; Kuske, Cheryl R.; Smith, Conor

    2012-12-12

    In this paper, we used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strainmore » dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. Finally, a comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.« less

  20. Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

    SciTech Connect

    King, Gary M.; Judd, Craig; Kuske, Cheryl R.; Smith, Conor

    2012-12-12

    In this paper, we used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strain dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. Finally, a comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.

  1. Comparative Transcriptome Analysis of Two Oysters, Crassostrea gigas and Crassostrea hongkongensis Provides Insights into Adaptation to Hypo-Osmotic Conditions

    PubMed Central

    Zhao, Xuelin; Yu, Hong; Kong, Lingfeng; Liu, Shikai; Li, Qi

    2014-01-01

    Environmental salinity creates a key barrier to limit the distribution of most aquatic organisms. Adaptation to osmotic fluctuation is believed to be a factor facilitating species diversification. Adaptive evolution often involves beneficial mutations at more than one locus. Bivalves hold great interest, with numerous species living in waters, as osmoconformers, who maintain the osmotic pressure balance mostly by free amino acids. In this study, 107,076,589 reads from two groups of Crassostrea hongkongensis were produced and the assembled into 130,629 contigs. Transcripts putatively involved in stress-response, innate immunity and cell processes were identified according to Gene ontology and KEGG pathway analyses. Comparing with the transcriptome of C. gigas to characterize the diversity of transcripts between species with osmotic divergence, we identified 182,806 high-quality single nucleotide polymorphisms (SNPs) for C. hongkongensis, and 196,779 SNPs for C. gigas. Comparison of 11,602 pairs of putative orthologs allowed for identification of 14 protein-coding genes that experienced strong positive selection (Ka/Ks>1). In addition, 45 genes that may show signs of moderate positive selection (1≥Ka/Ks>0.5) were also identified. Based on Ks ratios and divergence time between the two species published previously, we estimated a neutral transcriptome-wide substitution mutation rate of 1.39×10−9 per site per year. Several genes were differentially expressed across the control and treated groups of each species. This is the first time to sequence the transcriptome of C. hongkongensis and provide the most comprehensive transcriptomic resource available for it. The increasing amount of transcriptome data on Crassostrea provides an excellent resource for phylogenetic analysis. A large number of SNPs identified in this work are expected to provide valuable resources for future marker and genotyping assay development. The analysis of natural selection provides an

  2. 1,1-Diphenyl-2-picrylhydrazyl radical and superoxide anion scavenging activity of Rhizophora mangle (L.) bark

    PubMed Central

    Sánchez, Janet Calero; García, Roberto Faure; Cors, Ma. Teresa Mitjavila

    2010-01-01

    Background: Rhizophora mangle (L.) produce a variety of substances that possesses pharmacological actions. Although it shown antioxidant properties in some assays, there is no available information about its effect on some free radical species. So the objective of the present research is to evaluate the DPPH radical and superoxide anion scavenging properties of R. mangle extract and its polyphenol fraction. Methods: Rhizophora mangle (L.) bark aqueous extract and its major constituent, polyphenols fraction, were investigated for their antioxidant activities employing 2 in vitro assay systems: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals scavenging. Results: IC50 for DPPH radical-scavenging activity was 6.7 µg tannins/mL for extract and 7.6 µg tannins/mL for polyphenolic fraction. The extract showed better activity than its fraction (P < 0.05) in the DPPH radicals reducing power. Polyphenolic fraction exhibited better superoxide anion scavenging ability (IC50 = 21.6 µg tannins/mL) than the extract (IC50 = 31.9 µg tannins/mL). Antioxidant activities of both samples increased with the rise of tannins concentration. The comparison of regression lines showed significant differences (P < 0.05) between extract and its polyphenolic fraction in both assays, indicating that extract was more effective in DPPH radical scavenging than its fraction at tannin concentrations below the crossing point of both lines, while that fraction was more effective than extract inhibiting the superoxide anions generation. Conclusions: R. mangle aqueous extract showed a potent antioxidant activity, achieved by the scavenging ability observed against DPPH radicals and superoxide anions. Regarding its polyphenolic composition, the antioxidant effects observed in this study are due, most probably, to the presence of polyphenolic compounds. PMID:21589751

  3. Measurement of mass attenuation coefficients of Rhizophora spp. binderless particleboards in the 16.59-25.26 keV photon energy range and their density profile using x-ray computed tomography.

    PubMed

    Marashdeh, M W; Bauk, S; Tajuddin, A A; Hashim, R

    2012-04-01

    The mass attenuation coefficients of Rhizophora spp. binderless particleboard with four different particle sizes (samples A, B, C and D) and natural raw Rhizophora spp. wood (sample E) were determined using single-beam photon transmission in the energy range between 16.59 and 25.26 keV. This was done by determining the attenuation of K(α1) X-ray fluorescent (XRF) photons from niobium, molybdenum, palladium, silver and tin targets. The results were compared with theoretical values of young-age breast (Breast 1) and water calculated using a XCOM computer program. It was found that the mass attenuation coefficient of Rhizophora spp. binderless particleboards to be close to the calculated XCOM values in water than natural Rhizophora spp. wood. Computed tomography (CT) scans were then used to determine the density profile of the samples. The CT scan results showed that the Rhizophora spp. binderless particleboard has uniform density compared to natural Rhizophora spp. wood. In general, the differences in the variability of the profile density decrease as the particle size of the pellet samples decreases. PMID:22304963

  4. Arsenic and arsenic species in cultured oyster (Crassostrea gigas and C. corteziensis) from coastal lagoons of the SE Gulf of California, Mexico.

    PubMed

    Bergés-Tiznado, Magdalena E; Páez-Osuna, Federico; Notti, Alessandra; Regoli, Francesco

    2013-01-01

    The aim of this study was to evaluate the bioavailability of arsenic (As) through cultured oyster Crassostrea gigas and Crassostrea corteziensis from four coastal lagoons (SE Gulf of California). Organisms were collected in two seasons (rainy and dry season), and they were analyzed for total arsenic and chemical speciation of this element. The concentrations of As in oyster soft tissue fluctuated between 5.44 and 9.56 μg/g for rainy season and 6.46 and 8.33 μg/g for dry season (dry weight) in C. gigas. In C. corteziensis, the As concentrations were <5 μg/g for both seasons (dry weight). Arsenic speciation indicated arsenobetaine as the major arseno-compound accounting for 43.2-76.3 % of total content of As. Lower contributions were obtained for non-extractable As (11.3-17.5 %) and other molecules such as arsenocholine and methyl-arsonate (<5 %). Inorganic arsenic was detectable in only two samples, at concentrations lower than <0.1 μg/g. These As data are the first generated for these mollusks in NW Mexico and indicate that C. gigas and C. corteziensis farmed in this area are safe for human consumption in terms of arseno-compounds. PMID:23129525

  5. First report of Perkinsus beihaiensis in Crassostrea madrasensis from the Indian subcontinent.

    PubMed

    Sanil, N K; Suja, G; Lijo, J; Vijayan, K K

    2012-04-26

    Protozoan parasites of the genus Perkinsus are considered important pathogens responsible for mass mortalities in many wild and farmed bivalve populations. The present study was initiated to screen populations of the Indian edible oyster Crassostrea madrasensis, a promising candidate for aquaculture along the Indian coasts, for the presence of Perkinsus spp. The study reports the presence of P. beihaiensis for the first time in C. madrasensis populations from the Indian subcontinent and south Asia. Samples collected from the east and west coasts of India were subjected to Ray's fluid thioglycollate medium (RFTM) culture and histology which indicated the presence of Perkinsus spp. PCR screening of the tissues using specific primers amplified the product specific to the genus Perkinsus. The taxonomic affinities of the parasites were determined by sequencing both internal transcribed spacer (ITS) and actin genes followed by basic local alignment search tool (BLAST) analysis. Analysis based on the ITS sequences showed 98 to 100% identity to Perkinsus spp. (P. beihaiensis and Brazilian Perkinsus sp.). The pairwise genetic distance values and phylogenetic analysis confirmed that 2 of the present samples belonged to the P. beihaiensis clade while the other 4 showed close affinities with the Brazilian Perkinsus sp. clade. The genetic divergence data, close affinity with the Brazilian Perkinsus sp., and co-existence with P. beihaiensis in the same host species in the same habitat show that the remaining 4 samples exhibit some degree of variation from P. beihaiensis. As expected, the sequencing of actin genes did not show any divergence among the samples studied. They probably could be intraspecific variants of P. beihaiensis having a separate lineage in the process of evolution. PMID:22535871

  6. A cytokine-like factor astakine accelerates the hemocyte production in Pacific oyster Crassostrea gigas.

    PubMed

    Li, Yiqun; Jiang, Shuai; Li, Meijia; Xin, Lusheng; Wang, Lingling; Wang, Hao; Qiu, Limei; Song, Linsheng

    2016-02-01

    Astakine has been reported to be a hematopoietic growth factor of prokineticin homolog firstly found in arthropods freshwater crayfish Pacifastacus leniusculus. In the present study, an astakine homologous gene was identified from Pacific oyster Crassostrea gigas (designated CgAstakine). The full length cDNA of CgAstakine encoded a polypeptide of 103 amino acids containing a prokineticin (PK) domain homologous to that in astakine from freshwater crayfish P. leniusculus. The deduced amino acid sequence of CgAstakine shared higher similarity with those of other invertebrate astakines than prokineticins from vertebrates. The mRNA of CgAstakine was highly expressed in hepatopancreas and adductor muscle of oyster, while the CgAstakine protein was mainly distributed in hepatopancreas, gill and hemocytes. The mRNA expression of CgAstakine in hemocytes was significantly increased (p < 0.01) and maintained at a high level from 3 h to 9 h after Vibrio anguillarum challenge. After the oyster hemocytes were incubated with 5 μg/mL recombinant CgAstakine protein (rCgAstakine) for 24 h in vitro, the proliferation of hemocytes was significantly increased to 1.89 fold of that in control group (p < 0.05). Moreover, the total count of oyster hemocytes was significantly upregulated (2.45 fold of that in control group, p < 0.05) at 12 h after the oysters were received an injection of rCgAstakine (0.5 μg/g). These results collectively indicated that CgAstakine could modulate the hemocytes proliferation both in vitro and in vivo, and probably involved in the hematopoietic process fighting against the invasion of foreign pathogens. PMID:26523496

  7. Caspase-3 serves as an intracellular immune receptor specific for lipopolysaccharide in oyster Crassostrea gigas.

    PubMed

    Xu, Jiachao; Jiang, Shuai; Li, Yiqun; Li, Meijia; Cheng, Qi; Zhao, Depeng; Yang, Bin; Jia, Zhihao; Wang, Lingling; Song, Linsheng

    2016-08-01

    Apoptosis is a form of programmed cell death process controlled by a family of cysteine proteases called caspases, which plays a crucial role in the immune system homeostasis. The apoptosis and the detailed regulation mechanism have been well studied in vertebrate, but the information in lower animals, especially invertebrates, is still very limited. In the present study, Caspase-3 in the Pacific oyster Crassostrea gigas (designated CgCaspase-3) was enriched by lipopolysaccharide (LPS) affinity chromatography and further identified by MALDI-TOF/TOF-mass spectrometry. The binding activity of CgCaspase-3 to LPS was confirmed by enzyme-linked immunosorbent assay, and surface plasmon resonance analysis revealed its high binding specificity and moderate binding affinity (KD = 1.08 × 10(-6) M) to LPS. The recombinant CgCaspase-3 exhibited high proteolytic activity to substrate Ac-DEVD-pNA and relatively weak activity to substrate Ac-DMQD-pNA and Ac-VDQQD-pNA. The binding of CgCaspase-3 to LPS significantly inhibited its proteolytic activity toward AC-DEVD-pNA in vitro. The over-expression of CgCaspase-3 leaded to the phosphatidylserine exposure on the external plasma membrane and the cleavage of poly (ADP-ribose) polymerase, which reduced cell viability, and finally induced cell apoptosis. But the cell apoptosis mediated by CgCaspase-3 in vivo was significantly inhibited by the treatment of LPS. These results collectively indicated that CgCaspase-3 could serve as an intracellular LPS receptor, and the interaction of LPS with CgCaspase-3 specifically inhibited the cell apoptosis induced by CgCaspase-3. PMID:26993662

  8. Allograft Inflammatory Factor 1 Functions as a Pro-Inflammatory Cytokine in the Oyster, Crassostrea ariakensis

    PubMed Central

    Xu, Ting; Liu, Xiao; Wu, Xinzhong

    2014-01-01

    The oyster Crassostrea ariakensis is an economically important bivalve species in China, unfortunately it has suffered severe mortalities in recent years caused by rickettsia-like organism (RLO) infection. Prevention and control of this disease is a priority for the development of oyster aquaculture. Allograft inflammatory factor-1 (AIF-1) was identified as a modulator of the immune response during macrophage activation and a key gene in host immune defense reaction and inflammatory response. Therefore we investigated the functions of C. ariakensis AIF-1 (Ca-AIF1) and its antibody (anti-CaAIF1) in oyster RLO/LPS-induced disease and inflammation. Ca-AIF1 encodes a 149 amino acid protein containing two typical Ca2+ binding EF-hand motifs and shares a 48–95% amino acid sequence identity with other animal AIF-1s. Tissue-specific expression analysis indicates that Ca-AIF1 is highly expressed in hemocytes. Significant and continuous up-regulation of Ca-AIF1 is detected when hemocytes are stimulated with RLO/LPS (RLO or LPS). Treatment with recombinant Ca-AIF1 protein significantly up-regulates the expression levels of LITAF, MyD88 and TGFβ. When anti-CaAIF1 antibody is added to RLO/LPS-challenged hemocyte monolayers, a significant reduction of RLO/LPS-induced LITAF is observed at 1.5–12 h after treatment, suggesting that interference with Ca-AIF1 can suppress the inflammatory response. Furthermore, flow cytometric analysis indicated that anti-CaAIF1 administration reduces RLO/LPS-induced apoptosis and necrosis rates of hemocytes. Collectively these findings suggest that Ca-AIF1 functions as a pro-inflammatory cytokine in the oyster immune response and is a potential target for controlling RLO infection and LPS-induced inflammation. PMID:24759987

  9. Depuration of metals by the green-colored oyster Crassostrea sikamea.

    PubMed

    Wang, Lei; Wang, Wen-Xiong

    2014-10-01

    The accumulation of metals (especially copper) in oysters has led to green-color now being found in Chinese estuaries. In the present study, the authors quantified the depuration of 8 metals (Ag, Cd, Co, Cr, Cu, Ni, Pb, and Zn) in green-colored oysters (Crassostrea sikamea) collected from an estuary that is heavily contaminated by metals as a result of industrial effluent releases. The oysters were depurated under laboratory conditions for 4 mo; the accumulated concentrations and the subcellular distribution of metals were measured at different time intervals. Results showed that the green color of oysters faded to light yellow (nearly normal) after 4 mo of depuration. Depuration of metals could be described by a first-order kinetic process. The calculated overall depuration rate constants of metals were in the range of 0.008 d(-1) to 0.024 d(-1) , with a biological retention half-life of 30 d to 70 d. The depuration rates of green-colored contaminated oysters were significantly higher for Cd, Cu, Cr, and Ni than the rates of oysters from a less contaminated site, whereas the depuration rates of Ag, Co, Pb, and Zn were comparable between the 2 populations. When corrected for the change of oyster tissue weight, the actual efflux rate constants of the metals (0.0708-0.1014 d(-1) ) were much higher than the overall depuration rate constants. Cellular debris and metallothionein-like proteins were the important fractions binding with the metals in the oysters. Significant changes in metal subcellular distribution were observed during the 4-mo depuration for Ag, Cd, Cu, and Zn. Metallothionein-like protein became more important in sequestering the metals during the depuration period, with a concomitant decrease in metals associated with the cellular debris fraction. PMID:25053576

  10. The inhibitory role of γ-aminobutyric acid (GABA) on immunomodulation of Pacific oyster Crassostrea gigas.

    PubMed

    Li, Meijia; Qiu, Limei; Wang, Lingling; Wang, Weilin; Xin, Lusheng; Li, Yiqun; Liu, Zhaoqun; Song, Linsheng

    2016-05-01

    γ-aminobutyric acid (GABA) is an inhibitory neurotransmitter to suppress the immune-mediated pro-inflammatory reactions, and it has been used in the treatment of many inflammation-related diseases in vertebrates, while its immunomodulatory role in invertebrates has never been reported. In the present study, GABA was found to exist in the hemolymph of Pacific oyster Crassostrea gigas, and its concentration decreased slightly from 8.00 ± 0.37 μmol L(-1) at normal condition to 7.73 ± 0.15 μmol L(-1) at 6 h after LPS stimulation, and then increased to 9.34 ± 0.15 μmol L(-1), 8.86 ± 0.68 μmol L(-1) at 12 h and 48 h, respectively. After LPS stimulation, the mRNA expressions of pro-inflammatory cytokines (CgIL-17 and CgTNF) and immune effectors (CgSOD and CgBPI), and the protein expression of NOS increased significantly, and these increased trends were remarkably inhibited by GABA stimulation. At the same time, the phagocytosis rate and apoptosis rate of immunocytes also increased obviously after LPS stimulation, whereas the increase was repressed with the addition of GABA. The results collectively demonstrated that GABA was an indispensable inhibitory agent for both humoral and cellular immune response, which mainly functioned at the late phase of immune response to avoid the excess immune reactions and maintain the immune homeostasis. PMID:26975413

  11. Determining the mass attenuation coefficient, effective atomic number, and electron density of raw wood and binderless particleboards of Rhizophora spp. by using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Marashdeh, Mohammad W.; Al-Hamarneh, Ibrahim F.; Abdel Munem, Eid M.; Tajuddin, A. A.; Ariffin, Alawiah; Al-Omari, Saleh

    Rhizophora spp. wood has the potential to serve as a solid water or tissue equivalent phantom for photon and electron beam dosimetry. In this study, the effective atomic number (Zeff) and effective electron density (Neff) of raw wood and binderless Rhizophora spp. particleboards in four different particle sizes were determined in the 10-60 keV energy region. The mass attenuation coefficients used in the calculations were obtained using the Monte Carlo N-Particle (MCNP5) simulation code. The MCNP5 calculations of the attenuation parameters for the Rhizophora spp. samples were plotted graphically against photon energy and discussed in terms of their relative differences compared with those of water and breast tissue. Moreover, the validity of the MCNP5 code was examined by comparing the calculated attenuation parameters with the theoretical values obtained by the XCOM program based on the mixture rule. The results indicated that the MCNP5 process can be followed to determine the attenuation of gamma rays with several photon energies in other materials.

  12. EFFECTS OF CONTINUOUS CHLORINATION ON SPAT OF THE AMERICAN OYSTER ('CRASSOSTREA VIRGINICA')

    EPA Science Inventory

    Newly settled spat of the American oyster (Crassostrea virginica) exhibited reduced survival and growth when exposed to chronic chlorination (as Na-OCl). Spat exposed to nominal concentrations of 0.250 and 0.500 mg per 1 chlorine-produced oxidant (CPO) had only 20% survival after...

  13. PARASITIC AND SYMBIOTIC FAUNA INHABITING OYSTERS (CRASSOSTREA VIRGINICA) SAMPLED FROM THE CALOOSAHATCHEE ESTUARY, FL

    EPA Science Inventory

    Oysters, Crassostrea virginica, inhabiting 5 sites in the Caloosahatchee River estuary were studied over a 13 month period to determine the suitability of oyster habitat in relation to their health and condition. Histological examination of 650 oysters (10 animals per station per...

  14. BENZO(A)PYRENE METABOLISM IN THE AMERICA OYSTER 'CRASSOSTREA VIRGINICA'

    EPA Science Inventory

    The research program was initiated with the overall objective of determining the role of NADPH-dependent microsomal mono-oxygenase in the metabolism of the widespread environmental carcinogen benzo(a)pyrene (BP) by the oyster Crassostrea virginica. This enzyme system is important...

  15. IN VITRO KILLING OF PERKINSUS MARINUS BY HEMOCYTES OF OYSTERS CRASSOSTREA VIRGINICA

    EPA Science Inventory

    Presented at the 92nd Annual Meeting of the National Shellfisheries Association, 19-23 March 2000, Seattle, WA.

    A colorimetric microbicidal assay was adapted, optimized and used in experiments to characterize the capacity of eastern oyster (Crassostrea virginica) hemocytes...

  16. SETTLEMENT AND SURVIVAL OF THE OYSTER CRASSOSTREA VIRGINICA ON CREATED OYSTER REEF HABITATS IN CHESAPEAKE BAY

    EPA Science Inventory

    Efforts to restore the Eastern oyster (Crassostrea virginica) reef habitats in Chesapeake Bay typically begin with the placement of hard substrata to form three-dimensional mounds on the seabed to serve as a base for oyster recruitment and growth. A shortage of oyster shell for ...

  17. A POTENTIAL ECOFORECAST FOR PROTOZOAL INFECTIONS OF THE EASTERN OYSTER (CRASSOSTREA VIRGINICA)

    EPA Science Inventory

    McLaughlin, Shawn M. and Stephen J. Jordan. 2003. Potential Ecoforecast for Protozoal Infections of the Eastern Oyster (Crassostrea virginica) in the Upper Chesapeake Bay. In: Ecological Forecasting: New Tools for Coastal Marine Ecosystem Management. Nathalie Valette-Silver and D...

  18. Impact of Coastal Pollution on Microbial and Mineral Profile of Edible Oyster (Crassostrea rivularis) in the Coastal Waters of Andaman.

    PubMed

    Seetharaman, Prabukumar; Sarma, Kamal; George, Grinson; Krishnan, Pandian; Roy, S Dam; Sankar, Kiruba

    2015-11-01

    The impact of coastal pollution was studied using edible oysters, Crassostrea rivularis as an indicator at two sites viz., North Wandoor (NW) and Phoenix Jetty (PJ) in Port Blair, Andaman. The hydrographic parameters showed that nitrite, nitrate and phosphate concentration were less and dissolved oxygen were more at NW compared to PJ. The oysters were collected from the study sites and biochemical, microbial, mineral profiles and ATPase activities were estimated. ATPase activity was inhibited in the gill tissue of oysters (p<0.05) of PJ sample. Total microbial load in the water and oyster, and coliform bacteria (MPN) in the water were significantly (p<0.05) higher at PJ compared to the NW. There was no significant difference (p>0.05) in the mineral profile of water collected from both the sites. However, calcium and magnesium were more in the oysters collected from NW (p<0.05), and Cu, Zn and Cd were more in PJ samples (p<0.05). PMID:26347459

  19. Salinity influences the biochemical response of Crassostrea angulata to Arsenic.

    PubMed

    Moreira, Anthony; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-07-01

    The increasing rate of occurrence and persistence of climatic events causing salinity shifts, in combination with contamination, may further challenge organisms response to environmental stress. Hence, we studied the effects of different salinity levels (10, 20, 30 and 40) on the response of the oyster Crassostrea angulata to Arsenic (As) exposure (4 mg L(-1)). Total As, Na(+) and K(+) concentrations in oyster tissues were determined. Biochemical analysis were performed to assess osmotic regulation (CA), metabolism (ETS), enzymatic (SOD, CAT and GSTs) and non-enzymatic (GSH/GSSG and LPO) markers of oxidative stress. Results obtained showed significantly higher metabolic activities in oysters maintained in low salinity (10) exposure, coupled with higher As accumulation, as well as higher SOD and CAT activities, compared to higher salinities (30 and 40). GSTs activity and LPO levels were higher in oysters exposed to As at salinities 20, 30 and 40, compared to the same conditions without As. From our findings we concluded that the response of C. angulata to As is influenced by salinity. At the lowest salinity (10) oysters accumulated higher As concentrations, here attributed to higher metabolic rate involved in physiological osmoregulation, also stimulating antioxidant related enzymes activity (SOD and CAT) and thus preventing increased LPO (higher ETS activity also observed without As). On the contrary, at salinities 30 and 40 with As, antioxidant SOD and CAT were inhibited, enabling for LPO generation. Given our results, the effects of As on the oysters antioxidant capacity appears to be more deleterious under higher salinities (20, 30 and 40), comparing to salinity 10. The differentiated responses demonstrated in the present study in C. angulata oysters exposed to As under different salinities, bring new insights on the mechanisms of environmental adaptability of this species, namely to salinity shifts, and the interactions between such alterations and As

  20. Shell disease in eastern oysters, Crassostrea virginica, reared in France.

    PubMed

    Renault, T; Chollet, B; Cochennec, N; Gerard, A

    2002-01-01

    Progeny of eastern oyster, Crassostrea virginica, introduced into France in 1992, were reared in IFREMER facilities to test their growth performances. During the summer of 1993, sporadic mass mortalities (80-90%) occurred among C. virginica spat reared in the IFREMER laboratories in La Tremblade (Charente Maritime, France) and Bouin (Vendée, France). Affected oysters presented mantle retraction and deposition of an anomalous conchiolin layer on the inner surface of the shell. The incidence of oysters with gross signs exceeded 80%. No obvious pathogen was identified in soft tissues by histology and transmission electron microscopy (TEM). However, histological examination showed the presence of anomalous basophilic round structures, 0.5-1 microm in diameter, in gill and mantle connective tissues. These extracellular Feulgen-negative structures reacted positively with the von Kossa stain. TEM examination on mantle and gill samples in diseased spat showed that the basophilic bodies consisted of concentric deposits of an amorphous substance interpreted as containing calcium. These observations may indicate that the mineralization process in spat shells was disturbed without exact determination of the cause. Based on the similarities of the gross signs to those reported in juvenile eastern oysters in the United States, we believe that the cause of the mortalities observed in France was probably the Juvenile Oyster Disease. Moreover, we report for the first time the detection of anomalous amorphous structures in gill and mantle connective tissues associated with mortalities and deposition of an anomalous conchioloin layer on the inner shell surface in C. virginica spat. PMID:12054781

  1. PROTOZOAL INFECTIONS OF THE EASTERN OYSTER (CRASSOSTREA VIRGINICA) IN THE UPPER CHESAPEAKE BAY: A POTENTIAL ECOLOGICAL FORECAST

    EPA Science Inventory

    Perkinsus marinus and Haplosporidium nelsoni cause devasting infections in populations of the eastern oyster, Crassostrea virginica, along the US Atlantic coast and Gulf of Mexico. Salinity and temperature are considered major controlling factors in the prevalence and infection i...

  2. EFFECTS OF PHYSICOCHEMICAL FACTORS AND BACTERIAL COLONY MORPHOTYPE ON ASSOCIATION OF VIBRIO VULNIFICUS WITH HEMOCYTES OF CRASSOSTREA VIRGINICA

    EPA Science Inventory

    Vibrio vulnificus is a naturally occurring marine bacterium which causes invasive disease of immunocompromised humans following consumption of raw oysters. t is natural flora of Gulf Coast estuaries and has been found to inhabit tissues of oysters, Crassostrea virginica (Gmelin, ...

  3. AN OVACYSTIS-LIKE CONDITION IN THE AMERICAN OYSTER CRASSOSTREA VIRGINICA GMELIN FROM THE NORTHEASTERN GULF OF MEXICO

    EPA Science Inventory

    Histological examination of the eastern oyster, Crassostrea virginica, from a study in Pensacola Bay, Florida, revealed two cases of abnormally large, basophilic ova that resemble ovacystis disease previously reported in oysters from Maine and Long Island. The hypertrophied gamet...

  4. GREATER HEMOCYTE BACTERICIDAL ACTIVITY IN OYSTERS (CRASSOSTREA VIRGINICA) FROM A RELATIVELY CONTAMINATED SITE IN PENSACOLA BAY, FLORIDA.

    EPA Science Inventory

    Bivalve mollusks such as Crassostrea virginica inhabiting polluted estuaries and coastal areas may bioaccumulate high concentrations of contaminants without apparent ill effects. However, changes in putative internal defense activities have been associated with contaminant accumu...

  5. PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS

    EPA Science Inventory

    The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994 - December 1995) of oysters, Crassostrea virginica, on an artificial reef located in the Piankatank River, Virginia. The infecti...

  6. Combined effect of lime (Citrus aurantitolia) and drying on reducing bacteria of public health significance in Edible Oyster (Crassostrea madrasensis).

    PubMed

    Hassan, Femeena; Geethalakshmi, V; Jeeva, J Charles; Babu, M Remya

    2013-02-01

    Combined effect of lime and drying on bacteria of public health significance in Edible Oyster (Crassostrea madrasensis) from Munambam coastal belt (Kerala, India) were studied (without depuration). Samples were examined for Total Plate Count (TPC), Staphylococcus aureus (hygiene indicator), Total coliforms, Faecal coliforms, Escherichia coli, (faecal indicator) Faecal Streptococci (faecal indicator), Salmonella, Vibrio cholera and Listeria monocytogenes. The fresh oyster meat though did not confirm to the specifications laid by National shellfish sanitation programme (NSSP), after treatment with lime with and without drying found to show significant reduction in counts and meet the required standards. Prevalence of faecal indicators in the fresh sample indicated faecal pollution in the area. The isolation of potentially pathogenic bacteria, V. parahaemolyticus in fresh sample indicates high risk of people consuming and handling oysters in raw and semi processed form and also it may lead to cross contamination. The present study indicates that treatment with natural organic product like lime and simple preservation technique, drying can effectively reduce the bacterial load. The study also revealed that TPC of water and soil collected from the site from where oysters were collected was less than from the meat. PMID:24425910

  7. Isolation and Expression Analysis of Novel Silicon Absorption Gene from Roots of Mangrove (Rhizophora apiculata) via Suppression Subtractive Hybridization

    PubMed Central

    Sahebi, Mahbod; Hanafi, Mohamed M.; Abdullah, Siti Nor Akmar; Rafii, Mohd Y.; Azizi, Parisa; Nejat, Naghmeh; Idris, Abu Seman

    2014-01-01

    Silicon (Si) is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots' cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein. PMID:24516858

  8. Genetic variation and population genetic structure of Rhizophora apiculata (Rhizophoraceae) in the Greater Sunda Islands, Indonesia using microsatellite markers.

    PubMed

    Yahya, Andi Fadly; Hyun, Jung Oh; Lee, Jae Ho; Kim, Yong Yul; Lee, Kyung Mi; Hong, Kyung Nak; Kim, Seung-Chul

    2014-03-01

    Genetic variations within and among Rhizophora apiculata populations in the Greater Sunda Islands of Indonesia were studied using microsatellite markers. The study found 38 alleles on five loci in 15 populations. The observed (H(o)) and expected (H(e)) heterozygosity values are 0.338 and 0.378, respectively. Inbreeding effect from self-pollination might explain its heterozygote deficiency. Population genetic differentiation (F(ST) = 0.381) was similar to other mangrove species. The genetic diversity of R. apiculata populations along the coastline inside the archipelago (e.g., Buleleng, Donggala, Mamuju, and Takalar) was higher than those of population along the coastline outside the archipelago, especially northern Sumatra populations (i.e., Langkat, Tapanuli Tengah, Dumai, and Padang). The isolation by distances and sea currents directions as well as their connectivity might affect the gene flow and genetic exchange. The more isolated with fewer connections by sea currents, the smaller gene flow and genetic exchange observed between populations. The higher genetic exchange, on the contrary, occurred when population location was closer to the meeting point of the sea currents. The study also showed that the patterns of sea current movement seemed to have influence genetic clustering of populations which fell into three main groups (Sunda Shelf Mangroves) and one isolated population (New Guinea Mangroves). PMID:24323307

  9. The Use of a Chlorophyll Meter (SPAD-502) for Field Determinations of Red Mangrove (Rhizophora Mangle L.) Leaf Chlorophyll Amount

    NASA Technical Reports Server (NTRS)

    Connelly, Xana M.

    1997-01-01

    The red mangrove Rhizophora mangle L., is a halophytic woody spermatophyte common to the land-sea interface of tropical and subtropical intertidal zones. It has been reported that 60 to 75% of the coastline of the earth's tropical regions are lined with mangroves. Mangroves help prevent shoreline erosion, provide breeding, nesting and feeding areas for many marine animals and birds. Mangroves are important contributors of primary production in the coastal environment, and this is largely proportional to the standing crop of leaf chlorophylls. Higher intensities of ultraviolet radiation, resulting from stratospheric ozone depletion, can lead to a reduction of chlorophyll in terrestrial plants. Since the most common method for determining chlorophyll concentration is by extraction and this is labor intensive and time consuming, few studies on photosynthetic pigments of mangroves have been reported. Chlorophyll meter readings have been related to leaf chlorophyll content in apples and maples. It has also been correlated to nitrogen status in corn and cotton. Peterson et al., (1993) used a chlorophyll meter to detect nitrogen deficiency in crops and in determining the need for additional nitrogen fertilizer. Efforts to correlate chlorophyll meter measurements to chlorophyll content of mangroves have not been reported. This paper describes the use of a hand-held chlorophyll meter (Minolta SPAD-502) to determine the amount of red mangrove foliar chlorophyll present in the field.

  10. Nutrient removal in a closed silvofishery system using three mangrove species (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle).

    PubMed

    De-León-Herrera, R; Flores-Verdugo, F; Flores-de-Santiago, F; González-Farías, F

    2015-02-15

    The removal of ammonium (NH4(+)), nitrite (NO2(-)), nitrate (NO3(-)), and phosphate (PO4(-3)) in a closed silvofishery system was examined using three mangrove species (i.e., Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle). Specifically, six closed tanks were installed for this experiment with a population of 60 Dormitator latifrons fishes per tank. We planted 40 seedlings in each of three experimental tanks separated by species, while the remaining tanks were used as control. During 15 weeks, nutrient concentrations among the three mangrove systems presented no significant differences (P>0.05). However, nutrient removal variability was minimum during the last 2-5 weeks. Mangroves presented an average efficiency of 63% for the removal of NH4(+) and NO2(-). Contrary, the average removal potential of NO3(-) and PO4(-3) was 50%. Results from this study suggest that the three mangrove species could be used in a closed silvofishery systems for the biological removal of NH4(+), NO2(-), NO3(-), and PO4(-3). PMID:25499182

  11. A multivariate study of mangrove morphology (Rhizophora mangle) using both above and below-water plant architecture

    USGS Publications Warehouse

    Brooks, R.A.; Bell, S.S.

    2005-01-01

    A descriptive study of the architecture of the red mangrove, Rhizophora mangle L., habitat of Tampa Bay, FL, was conducted to assess if plant architecture could be used to discriminate overwash from fringing forest type. Seven above-water (e.g., tree height, diameter at breast height, and leaf area) and 10 below-water (e.g., root density, root complexity, and maximum root order) architectural features were measured in eight mangrove stands. A multivariate technique (discriminant analysis) was used to test the ability of different models comprising above-water, below-water, or whole tree architecture to classify forest type. Root architectural features appear to be better than classical forestry measurements at discriminating between fringing and overwash forests but, regardless of the features loaded into the model, misclassification rates were high as forest type was only correctly classified in 66% of the cases. Based upon habitat architecture, the results of this study do not support a sharp distinction between overwash and fringing red mangrove forests in Tampa Bay but rather indicate that the two are architecturally undistinguishable. Therefore, within this northern portion of the geographic range of red mangroves, a more appropriate classification system based upon architecture may be one in which overwash and fringing forest types are combined into a single, "tide dominated" category. ?? 2005 Elsevier Ltd. All rights reserved.

  12. Isolation and expression analysis of novel silicon absorption gene from roots of mangrove (Rhizophora apiculata) via suppression subtractive hybridization.

    PubMed

    Sahebi, Mahbod; Hanafi, Mohamed M; Abdullah, Siti Nor Akmar; Rafii, Mohd Y; Azizi, Parisa; Nejat, Naghmeh; Idris, Abu Seman

    2014-01-01

    Silicon (Si) is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots' cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein. PMID:24516858

  13. Tissue analysis of the oyster Crassostrea virginica after the Deepwater Horizon oil spill

    NASA Astrophysics Data System (ADS)

    Roopnarine, D.; Roopnarine, P. D.; Anderson, L.; Chung, T.

    2013-12-01

    The Deepwater Horizon accident (DWH) of April 20th, 2010, in the Gulf of Mexico (GoM) released crude oil into the ocean column for 4 months. An estimated 685,000 tons of crude oil was released, making DWH spill the largest accidental spill in maritime history. The immediate impacts of the spill were evident, including oil slicks, fouled beaches and fouled, often dead wildlife. Longer-term impacts are less understood, and reliance on studies of past spills, e.g. Exxon Valdez, may not be applicable given the substantially greater magnitude of DWH (Valdez spilled 37,000 tons) and different environmental settings (predominantly rocky shorelines vs. saltmarsh-dominated coastlines). Many molluscan species exhibit responses to oil spills or other hydrocarbon contamination. Bivalved molluscs are commonly used as bioindicator organisms in part because they concentrate both metals and organic contaminants in their soft tissues. We used the American oyster Crassostrea virginica to measure exposure to and impact of the spill as the abnormal transformation of soft-tissues, or metaplasia. Metaplasia is the reversible transformation of one cell type into another. Molluscan metaplasia has been associated with exposure to petroleum contamination. While oyster epithelium is normally stratified columnar and ciliated, experimental exposures often result in metaplasia of gill, digestive and renal tissues. The occurrence and frequency of metaplasia may also be an indication of the longevity of a spill's impact. For example, individuals of the mussel Mytilus trossulus in Prince William Sound continued to exhibit metaplasia of the digestive gland more than 5 years after the Exxon Valdez spill, with an occurrence directly related to concentrations of PAHs in the animals. We focused on the hypothesis that DWH spill exposure resulted in metaplasia of gill and digestive epithelial tissues, both during and after the spill. Those transformations are eventually reversible, although on an unknown

  14. CYTOLOGY AND BIOCHEMISTRY OF BROWN CELLS IN CRASSOTREA VIRGINICA COLLECTED FROM CLEAN AND CONTAMINATED STATIONS

    EPA Science Inventory

    This study examined brown cells of oysters, Crassostrea virginica, as potential indicators of pollution related stress. egardless of collection brown cells increased in connective tissue when it as inflamed. ignificantly (a < 0.05) fewer brown cells were observed in connective ti...

  15. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

    SciTech Connect

    Mohd Yusof, Mohd Fahmi Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz; Bauk, Sabar; Hashim, Rokiah

    2015-04-29

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

  16. Protease activity in the plasma of American oysters, Crassostrea virginica, experimentally infected with the protozoan parasite Perkinsus marinus.

    PubMed

    Muñoz, P; Vance, K; Gómez-Chiarri, M

    2003-10-01

    Perkinsus marinus is responsible for disease and mortality of the American oyster, Crassostrea virginica. To investigate the interactions between P. marinus and oyster hemocytes, protease activity was measured in plasma of oysters collected 4 hr, 24 hr, 4 days, and 2 mo after experimental infection with P. marinus. A significant increase in protease activity was observed in oyster plasma 4 hr after injection with P. marinus, followed by a sharp decrease within 24 hr. Gelatin-impregnated gel electrophoresis showed the presence of 2 major bands (60 and 112 kDa) and 3 less prevalent bands (35, 92, and 200 kDa) with metalloproteinaselike activity in the plasma of noninfected oysters. Additional bands in the 40- to 60-kDa range, corresponding to P. marinus serine proteases, were observed in oyster plasma at early time points after infection. A transient, but significant, decrease in the activity of oyster metalloproteinases was observed at early time points after infection. Coincubation of oyster plasma with P. marinus extracellular products resulted in a decrease in oyster metalloproteinases and several P. marinus proteases. This study provides insights into the role of proteases in the pathogenesis of Dermo disease. PMID:14627141

  17. Summer mortalities and detection of ostreid herpesvirus microvariant in Pacific oyster Crassostrea gigas in Sweden and Norway.

    PubMed

    Mortensen, Stein; Strand, Åsa; Bodvin, Torjan; Alfjorden, Anders; Skår, Cecilie K; Jelmert, Anders; Aspán, Anna; Sælemyr, Lisbeth; Naustvoll, Lars-Johan; Albretsen, Jon

    2016-01-13

    The Pacific oyster Crassostrea gigas has recently expanded its range in Scandinavia. The expansion is presumably a result of northwards larval drift. Massive settlements were recorded in many areas along the Swedish west coast and southern Norway in 2013 and 2014. After the spawning season in 2014, the temperature of the surface water peaked at 24-26°C. After this period, high and sudden mortalities occurred in a Swedish hatchery and in wild populations along the Swedish west coast and south coast of Norway. Surveys and collected data showed that mortalities mainly occurred during 3 wk in September. All size classes were affected, and affected populations displayed a patchy distribution with heavily affected and unaffected populations in close proximity. Flat oysters Ostrea edulis and blue mussels Mytilus edulis were unaffected. Ostreid herpesvirus (OsHV) was detected in moribund Pacific oyster spat as well as in surviving adults. The virus was identified as OsHV-1 μvar. This is the first detection of this variant in Scandinavia, showing that OsHV-1 μvar is present in areas with recent establishments of Pacific oysters, and where there is no aquaculture of this species. PMID:26758650

  18. The modulation of haemolymph arginine kinase on the extracellular ATP induced bactericidal immune responses in the Pacific oyster Crassostrea gigas.

    PubMed

    Jiang, Shuai; Jia, Zhihao; Chen, Hao; Wang, Lingling; Song, Linsheng

    2016-07-01

    Arginine kinase is an important phosphagen kinase (PK) which plays an essential role in ATP buffering systems in invertebrates. In the present study, an arginine kinase (designated CgAK) was isolated by the lipopolysaccharide (LPS) affinity chromatography from the haemolymph of Crassostrea gigas. CgAK could directly bind to LPS in a concentration-dependent manner with the dissociation constant (Kd) of 2.46 × 10(-6) M. The interaction with LPS significantly decreased the ATP hydrolytic activity of CgAK, which in turn lead to the accumulation of ATP in vitro. The extracellular ATP stimulation could induce Ca(2+) influx, reactive oxygen species (ROS) production, and the release of lysosomal enzyme in the cellular immune response. In addition, ATP stimulation provoked the bactericidal activity towards Escherichia coli, and the scavenging ROS with N-acetyl-l-cysteine (NAC) abrogated the bactericidal activity, indicating that ATP stimulation could induce ROS-dependent antimicrobial activity in haemocytes. Collectively, the results demonstrated that the haemolymph CgAK could serve as an important purinergic regulator to modulate extracellular ATP, which might further have an important effect on the purinergic signaling-activated innate immune response of oyster. PMID:27033465

  19. Ostreid herpesvirus type 1 genomic diversity in wild populations of Pacific oyster Crassostrea gigas from Italian coasts.

    PubMed

    Burioli, E A V; Prearo, M; Riina, M V; Bona, M C; Fioravanti, M L; Arcangeli, G; Houssin, M

    2016-06-01

    Ostreid herpesvirus 1 (OsHV-1) is a significant pathogen affecting the young Pacific oyster Crassostrea gigas, worldwide. A new variant, OsHV-1 μVar, has been associated with recurrent mortality events in Europe since 2008. Epidemiological data collection is key for global risk assessment; however little is known about health status and genotypes present in European wild oyster beds. Most studies to date have involved only cultivated individuals during mortality events, and reported low genotype diversity. With this study, conducted along the Italian coasts, we investigated for the first time the presence of OsHV-1 in European natural oyster beds. Analysis of three genomic regions revealed the presence of at least nine different genotypes, including two variants close to the OsHV-1 reference, known since the early 1990s but with no European record reported since 2010, and highlights relevant genotype diversity in natural environment. Phylogenetic analysis distinguished two distinct clusters and geographical distribution of genotypes, with the exception of a variant very closely related to the μVar, which appeared the single genotype present in all the Adriatic sites. Interestingly, these wild symptom free populations could represent, in Europe, an accessible alternative to the import of OsHV-1-resistant oyster strains from the East Pacific, the native area of C. gigas, avoiding the high-risk of non-native marine species and new pathogen introductions. PMID:27234424

  20. Effects of storage temperature and duration on toxicity of sediments assessed by Crassostrea gigas oyster embryo bioassay

    SciTech Connect

    Beiras, R.; His, E.; Seaman, M.N.L.

    1998-10-01

    The effects of temperature and duration of storage on the toxicity of estuarine sediments were investigated with the Crassostrea gigas oyster embryo bioassay. Sediments ranging from unpolluted (controls) to extremely polluted with heavy metals (>100 ppm Hg, Cu, Zn, and Pb) and total hydrocarbons (>1,000 ppm) were collected from sites in southwest France and northern Spain, Control sediments were toxic only at the highest concentrations tested and after freezing in liquid nitrogen ({minus}196 C). Polluted sediments significantly reduced the success of oyster embryogenesis. Analysis of variance showed that the effect of storage temperature on toxicity increased with the prolongation of storage. Prolonged storage of fresh (4 C) sediments resulted in a loss of toxicity, which was more rapid in the less-polluted sediments. Deep-frozen sediments ({minus}196 C) were highly toxic regardless of origin and storage time, and because deep-freezing causes spurious toxicity in the control samples, it cannot be recommended for toxicological studies. In the context of the assessment of sediment toxicity by embryo-larval bioassays, fresh (4 C) storage is recommended when sediments need to be stored for no longer than a few days. The advisable duration of fresh storage to avoid false-negative results is directly related to the degree of toxicity. Should the sediments require prolonged storage, freezing at {minus}20 C appears to be the best choice.

  1. Transcriptome of American Oysters, Crassostrea virginica, in Response to Bacterial Challenge: Insights into Potential Mechanisms of Disease Resistance

    PubMed Central

    McDowell, Ian C.; Nikapitiya, Chamilani; Aguiar, Derek; Lane, Christopher E.; Istrail, Sorin; Gomez-Chiarri, Marta

    2014-01-01

    The American oyster Crassostrea virginica, an ecologically and economically important estuarine organism, can suffer high mortalities in areas in the Northeast United States due to Roseovarius Oyster Disease (ROD), caused by the gram-negative bacterial pathogen Roseovarius crassostreae. The goals of this research were to provide insights into: 1) the responses of American oysters to R. crassostreae, and 2) potential mechanisms of resistance or susceptibility to ROD. The responses of oysters to bacterial challenge were characterized by exposing oysters from ROD-resistant and susceptible families to R. crassostreae, followed by high-throughput sequencing of cDNA samples from various timepoints after disease challenge. Sequence data was assembled into a reference transcriptome and analyzed through differential gene expression and functional enrichment to uncover genes and processes potentially involved in responses to ROD in the American oyster. While susceptible oysters experienced constant levels of mortality when challenged with R. crassostreae, resistant oysters showed levels of mortality similar to non-challenged oysters. Oysters exposed to R. crassostreae showed differential expression of transcripts involved in immune recognition, signaling, protease inhibition, detoxification, and apoptosis. Transcripts involved in metabolism were enriched in susceptible oysters, suggesting that bacterial infection places a large metabolic demand on these oysters. Transcripts differentially expressed in resistant oysters in response to infection included the immune modulators IL-17 and arginase, as well as several genes involved in extracellular matrix remodeling. The identification of potential genes and processes responsible for defense against R. crassostreae in the American oyster provides insights into potential mechanisms of disease resistance. PMID:25122115

  2. Phylogeographic pattern of Rhizophora (Rhizophoraceae) reveals the importance of both vicariance and long-distance oceanic dispersal to modern mangrove distribution

    PubMed Central

    2014-01-01

    Background Mangroves are key components of coastal ecosystems in tropical and subtropical regions worldwide. However, the patterns and mechanisms of modern distribution of mangroves are still not well understood. Historical vicariance and dispersal are two hypothetic biogeographic processes in shaping the patterns of present-day species distributions. Here we investigate evolutionary biogeography of mangroves in the Indo-West Pacific (IWP) and western Atlantic-East Pacific (AEP) regions using a large sample of populations of Rhizophora (the most representative mangrove genus) and a combination of chloroplast and nuclear DNA sequences and genome-wide ISSR markers. Results Our comparative analyses of biogeographic patterns amongst Rhizophora taxa worldwide support the hypothesis that ancient dispersals along the Tethys Seaway and subsequent vicariant events that divided the IWP and AEP lineages resulted in the major disjunctions. We dated the deep split between the Old and New World lineages to early Eocene based on fossil calibration and geological and tectonic changes. Our data also provide evidence for other vicariant processes within the Indo-West Pacific region in separating conspecific lineages of SE Asia and Australia-Pacific at the Oligocene-Miocene boundary. Close genetic affinities exist between extant Fijian and American lineages; East African and Australian lineages; and Australian and Pacific lineages; indicating relatively more recent oceanic long-distance dispersal events. Conclusions Our study demonstrates that neither vicariance nor dispersal alone could explain the observed global occurrences of Rhizophora, but a combination of vicariant events and oceanic long-distance dispersals can account for historical diversification and present-day biogeographic patterns of mangroves. PMID:24742016

  3. Regeneration of Rhizophora mucronata (Lamk.) in degraded mangrove forest: Lessons from point pattern analyses of local tree interactions

    NASA Astrophysics Data System (ADS)

    Olagoke, Adewole O.; Bosire, Jared O.; Berger, Uta

    2013-07-01

    Spatial structural patterns emerging from local tree interactions influence growth, mortality and regeneration processes in forest ecosystems, and decoding them enhance the understanding of ecological mechanisms affecting forest regeneration. Point-Patterns analysis was applied for the very first time to mangrove ecology to explore the spatial structure of Rhizophora mucronata regeneration in a disturbed mangrove forest; and the pattern of associations of juvenile-adult trees. R. mucronata trees were mapped in plots of 50 m × 10 m located at the seaward, central and landward edge along 50 m wide transect in the forest, and the mapped patterns were analysed with pair correlation and mark-connection functions. The population density of R. mucronata differed along the tidal gradient with the highest density in the central region, and the least near the shoreline. The study revealed that short distance propagule dispersal, resulting in the establishment of juveniles in closed distance to the mother trees, might not be the driving force for distribution of this species. The spatial structural pattern of R. mucronata population along tidal gradient showed a characteristic spatial aggregation at small scale, but randomly distributed as the distances become larger. There was a distinct spatial segregation between recruits and adult trees, and hence spatially independent. Though, adult-adult trees associations did not show a clear spatial segregation pattern; the recruit-recruit species associations exhibited significant clustering in space. Although habitat heterogeneity might be responsible for the local scale aggregation in this population, the effect of plant-plant conspecific interactions is more probable to inform the long-term structure and dynamics of the population of R. mucronata, and ditto for the entire forest.

  4. Rhizophora mucronata attenuates beta-amyloid induced cognitive dysfunction, oxidative stress and cholinergic deficit in Alzheimer's disease animal model.

    PubMed

    Suganthy, Natarajan; Malar, Dicson Sheeja; Devi, Kasi Pandima

    2016-08-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by accumulation and deposition of Aβ peptide in human brain. The present study aimed to determine the protective effect of catechin rich extract of MERM (methanolic extract of Rhizophora mucronata) on Aβ (25-35) induced cognitive impairment and neuronal toxicity in mice. In the present study AD characteristics were induced by intracerberoventricular administration of aggregated Aβ (25-35) in the Swiss albino mice. Learning and memory deficits were assessed using behavioral assays such as Morris water maze, Y-maze and step down avoidance tasks. Oxidative stress mediated impairment were assessed by measuring the activities of enzymatic and non-enzymatic antioxidants, level of apoptotic protein and oxidative markers in the hippocampus and frontal cortex region. Histolopathological analysis of brain was also carried out. Results illustrated that oral treatment of MERM (200 and 400 mg/kg bw) significantly attenuated Aβ (25-35) induced memory impairment as evaluated by behavioral tests. In addition treatment with MERM attenuated the elevation of β-secretase activity accompanying the reduced level of Aβ (25-35) in the cortex and hippocampus of brain. MERM also enhanced the cognitive function by significantly inhibiting AChE, BuChE and MAO-B. Furthermore, MERM attenuated lipid peroxidation, protein oxidation, restored the antioxidant status and inhibited neuronal apoptosis by down-regulating the level of caspase 3 and Bax protein. These data suggest that MERM rich in catechin can act as promising drug for AD treatment because of its antioxidant, anti-apoptotic and reducing Aβ oligomer activities. PMID:27188290

  5. Albino mutation rates in red mangroves (Rhizophora mangle L.) as a bioassay of contamination history in Tampa Bay, Florida, USA

    USGS Publications Warehouse

    Proffitt, C.E.; Travis, S.E.

    2005-01-01

    We assessed the sensitivity of a viviparous estuarine tree species, Rhizophora mangle, to historic sublethal mutagenic stress across a fine spatial scale by comparing the frequency of trees producing albino propagules in historically contaminated (n=4) and uncontaminated (n=11) forests in Tampa Bay, Florida, USA. Data from uncontaminated forests were used to provide estimates of background mutation rates. We also determined whether other fitness parameters were negatively correlated with mutagenic stress (e.g., degree of outcrossing and numbers of reproducing trees km-1). Contaminated sites in Tampa Bay had significantly higher frequencies of trees that were heterozygous for albinism per 1000 total reproducing trees (FHT) than uncontaminated forests (mean ?? SE: 11.4 ?? 4.3 vs 4.3 ?? 0.73, P 25 yrs of subsequent recruitment and tree replacement may have allowed an initial elevation in the FHT to decay. Patterns of FHT were not explained by distance from the bay mouth or the degree of urbanization. However, there was a significant positive relationship between tree size and FHT (r=0.83, P<0.018), which suggests that forests with older or larger trees provide a more lasting record of cumulative mutagenic stress. No other fitness parameters correlated with FHT. There was a difference in FHT between two latitudes, as determined by comparing Tampa Bay with literature values for Puerto Rico. The sensitivity of this bioassay for the effects of mutagens will facilitate future monitoring of contamination events and comparisons of bay-wide recovery in future decades. Development of a database of FHT values for a range of subtropical and tropical estuaries is underway that will provide a baseline against which to compare mutational consequences of global change. ?? 2005, The Society of Wetland Scientists.

  6. Community structure and estimated contribution of primary consumers (Nematodes and Copepods) of decomposing plant litter (Juncus roemerianus and Rhizophora mangle) in South Florida

    SciTech Connect

    Fell, J.W.; Cefalu, R.

    1984-01-01

    The paper discusses the meiofauna associated with decomposing leaf litter from two species of coastal marshland plants: the black needle rush, Juncus roemerianus and the red mangrove, Rhizophora mangle. The following aspects were investigated: (1) types of meiofauna present, especially nematodes; (2) changes in meiofaunal community structures with regard to season, station location, and type of plant litter; (3) amount of nematode and copepod biomass present on the decomposing plant litter; and (4) an estimation of the possible role of the nematodes in the decomposition process. 28 references, 5 figures, 9 tables. (ACR)

  7. Optimizing remote sensing and GIS tools for mapping and managing the distribution of an invasive mangrove (Rhizophora mangle) on South Molokai, Hawaii

    USGS Publications Warehouse

    D'Iorio, M.; Jupiter, S.D.; Cochran, S.A.; Potts, D.C.

    2007-01-01

    In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping accuracy for various sensor-technique combinations. ANOVA of accuracy assessments demonstrated significant differences among techniques, but no significant differences among the three sensors. We summarize advantages and disadvantages of each sensor and technique for mapping mangrove distributions in tropical coastal environments.

  8. Draft Genome Sequence of Aliiroseovarius crassostreae CV919-312, the Causative Agent of Roseovarius Oyster Disease (Formerly Juvenile Oyster Disease)

    PubMed Central

    Kessner, Linda; Spinard, Edward; Gomez-Chiarri, Marta; Rowley, David C.

    2016-01-01

    Aliiroseovarius crassostreae CV919-312 is a marine alphaproteobacterium and the causative agent of Roseovarius oyster disease. We announce here the draft genome sequence of A. crassostreae CV919-312 and identify potential virulence genes involved in pathogenicity. PMID:26988054

  9. Draft Genome Sequence of Aliiroseovarius crassostreae CV919-312, the Causative Agent of Roseovarius Oyster Disease (Formerly Juvenile Oyster Disease).

    PubMed

    Kessner, Linda; Spinard, Edward; Gomez-Chiarri, Marta; Rowley, David C; Nelson, David R

    2016-01-01

    Aliiroseovarius crassostreae CV919-312 is a marine alphaproteobacterium and the causative agent of Roseovarius oyster disease. We announce here the draft genome sequence of A. crassostreae CV919-312 and identify potential virulence genes involved in pathogenicity. PMID:26988054

  10. Perkinsus marinus tissue distribution and seasonal variation in oysters Crassostrea virginica from Florida, Virginia and New York.

    PubMed

    Oliver, L M; Fisher, W S; Ford, S E; Calvo, L M; Burreson, E M; Sutton, E B; Gandy, J

    1998-09-11

    Perkinsus marinus infection intensity was measured in eastern oysters Crassostrea virginica collected in October and December 1993, and March, May, and July 1994 from 3 U.S. sites: Apalachicola Bay (FL), Chesapeake Bay (VA), and Oyster Bay (NY). Gill, mantle, digestive gland, adductor muscle, hemolymph, and remaining tissue (including gonadal material and rectum) were dissected from 20 oysters from each site at each collection time. Samples were separately diagnosed for P. marinus infections by incubation in Ray's Fluid Thioglycollate Medium (RFTM) and subsequent microscopic quantification of purified enlarged hypnospores. At all sampling times and sites, average P. marinus infection intensity (g wet wt tissue-1 or ml hemolymph-1) was lowest in hemolymph samples, and generally highest in the digestive gland. Perkinsus marinus prevalence was 100% at both FL and NY sites for each of the 5 collection times, and, for the VA site, was less than 100% in only 1 month (May 1994). Seasonal intensity patterns and mean total body burdens differed among the sites. Average body burden was highest in VA during October and progressively declined to a minimum in May. This decline was probably due to mortality of heavily infected oysters and diminution of parasite activity associated with colder temperatures and reduced salinities. Intensities varied little during the months of October and December at both the FL and NY sites. Minimum average intensities were observed in March in FL oysters and May in NY oysters. Relatively high P. marinus infection levels that persisted throughout the winter in NY oysters compared with VA oysters could reflect constant high salinity in Long Island Sound which favors parasite activity, and also rapid decline in temperature in the fall that may have prevented epizootic oyster mortalities. PMID:9789979

  11. Determination of the antimutagenicity of an aqueous extract of Rhizophora mangle L. (Rhizophoraceae), using in vivo and in vitro test systems.

    PubMed

    Malini, Maressa; Marin-Morales, Maria Aparecida; Mantovani, Mário Sérgio; Jamal, Claudia Masrouah; Nati, Natália; da Silva Passos, Tatiane; Matsumoto, Silvia Tamie

    2010-01-01

    An aqueous extract of Rhizophora mangle L. bark is used as raw material in pottery making in the State of Espirito Santo, Brazil. This extract presents large quantities of tannins, compounds possessing antioxidant properties. Tannin antioxidant activity, as a plant chemical defense mechanism in the process of stabilizing free radicals, has been an incentive to studies on anti-mutagenicity. The present work aimed to evaluate possible antimutagenic activity of a R. mangle aqueous extract, using the Allium cepa test-system and micronuclear (MN) assay with blockage of cytokinesis in Chinese hamster ovary cells (CHO-K1). The Allium cepa test-system indicated antimutagenic activity against the damage induced by the mutagenic agent methyl methanesulfonate. A reduction in both MN cell frequency and chromosome breaks occurred in both the pre and post-treatment protocols. The MN testing of CHO-K1 cells revealed anti-mutagenic activity of the R. mangle extract against methyl methanesulfonate and doxorubicin in pre, simultaneous and post-treatment protocols. These results suggest the presence of phyto-constituents in the extract presenting demutagenic and bio-antimutagenic activities. Since the chemical constitution of Rhizophora mangle species presents elevated tannin content, it is highly probable that these compounds are the antimutagenic promoters themselves. PMID:21637623

  12. Survival of Infectious Cryptosporidium parvum Oocysts in Seawater and Eastern Oysters (Crassostrea virginica) in the Chesapeake Bay

    PubMed Central

    Fayer, Ronald; Graczyk, Thaddeus K.; Lewis, Earl J.; Trout, James M.; Farley, C. Austin

    1998-01-01

    Oocysts of Cryptosporidium parvum placed in artificial seawater at salinities of 10, 20, and 30 ppt at 10°C and at 10 ppt at 20°C were infectious after 12 weeks. Those placed in seawater at 20 ppt and 30 ppt at 20°C were infectious for 8 and 4 weeks, respectively. These findings suggested that oocysts could survive in estuarine waters long enough to be removed by filter feeders such as oysters. Thereafter, 30 Eastern oysters, Crassostrea virginica, were collected with a dredge or with hand tongs at each of six sites within Maryland tributaries of the Chesapeake Bay in May and June and in August and September of 1997. Hemocytes and gill washings from all oysters were examined for the presence of Cryptosporidium oocysts and Giardia cysts by immunofluorescence microscopy utilizing a commercially available kit containing fluorescein isothiocyanate-conjugated monoclonal antibodies. Giardia was not detected by this method from any of the 360 oysters examined. Presumptive identification of Cryptosporidium oocysts was made in either hemocytes or gill washings of oysters from all six sites both times that surveys were conducted. In addition, during August and September, for each of the six sites, hemocytes from the 30 oysters were pooled and gill washings from the oysters were pooled. Each pool was delivered by gastric intubation to a litter of neonatal mice to produce a bioassay for oocyst infectivity. Intestinal tissue from two of three mice that received gill washings from oysters collected at a site near a large cattle farm and shoreline homes with septic tanks was positive for developmental stages of C. parvum. These findings demonstrate for the first time that oysters in natural waters harbor infectious C. parvum oocysts and can serve as mechanical vectors of this pathogen. PMID:9501446

  13. Perkinsus marinus in pleasure oyster Crassostrea corteziensis from Nayarit, Pacific coast of México.

    PubMed

    Cáceres-Martínez, J; Vásquez-Yeomans, R; Padilla-Lardizábal, G; del Río Portilla, M A

    2008-09-01

    Culture of the pleasure oyster Crassostrea corteziensis is emerging as an alternative to the Pacific oyster (Crassostrea gigas) for oyster producers, who face severe mortalities since 1997 in Northwest México. For determining the health status of this species, we conducted a histopathological analysis of cultured populations from two estuaries in the Pacific coast of México. Macroscopical analysis revealed animals with transparent and retracted mantle. Histopathological analysis of these specimens showed tissue alterations and parasitic forms consistent with Perkinsus sp. infection. Stages of the parasite identified included tomont and trophozoites with an eccentric vacuole characteristic of Perkinsus spp. Pieces of tissues of infected oysters were incubated in Fluid Thioglycollate Medium (FTM) resulting in blue-black hypnospores after incubation. The identity of the parasite was confirmed by species specific PCR-based assay in DNA samples from oysters, tissue fractions from FTM cultures, and deparaffined samples with Perkinsus-like parasite detected by histology. Sequencing of positive amplified fragments (307bp) showed a sequence similar to Perkinsus marinus strain TXsc NTS ribosomal RNA gene (100% coverage and 98% identity, GenBank Accession No. AF497479.1) and to P. marinus, Genomic DNA, (100% coverage and 97% identity, GenBank Accession No. S78416.1). The prevalence of P. marinus varied from 1 to 5% in Boca del Camichín and from 1 to 6% in Pozo Chino. In general, the intensity of infection was moderate. The infection was observed in oysters from 31 to 110mm of shell length. This is the first record of P. marinus in oysters from the North America Pacific coast and the first record in C. corteziensis. The origin of this parasite in the area is unknown, but it may be associated to introductions of Crassostrea virginica from the East coast of United States of America or Gulf of México. PMID:18423484

  14. Application of a multiplex PCR for the detection of protozoan pathogens of the eastern oyster Crassostrea virginica in field samples.

    PubMed

    Russell, Spencer; Frasca, Salvatore; Sunila, Inke; French, Richard A

    2004-04-21

    Populations of eastern oysters Crassostrea virginica along the east coast of North America have repeatedly experienced epizootic mass mortality due to infections by protozoan parasites, and molecular diagnostic methodologies are fast becoming more widely available for the diagnosis of protozoan diseases of oysters. In this study we applied a modified version of an existing multiplex polymerase chain reaction (PCR) for detection of the eastern oyster parasites Haplosporidium nelsoni, H. costale and Perkinsus marinus from field-collected samples. We incorporated primers for DNA quality control based on the large subunit ribosomal RNA (LSU rRNA) gene of C. virginica. The multiplex PCR (MPCR) simultaneously amplified genomic DNA of C. virginica, and cloned DNA of H. nelsoni, P. marinus and H. costale. In field trial applications, we compared the performance of the MPCR to that of the conventional diagnostic techniques of histopathological tissue examination and the Ray/Mackin fluid thioglycollate medium (RMFT) assay. A total of 530 oysters were sampled from 18 sites at 12 locations along the east coast of the United States from the Gulf of Mexico to southern New England. The modified MPCR detected 21% oysters with H. nelsoni, 2% oysters with H. costale, and 40% oysters with P. marinus infections. In comparison, histopathological examination detected H. nelsoni and H. costale infections in 6 and 0.8% oysters, respectively, and the RMFT assay detected P. marinus infection in 31% oysters. The MPCR is a more sensitive diagnostic assay for detection of H. nelsoni, H. costale, and P. marinus, and incorporation of an oyster quality control product limits false negative results. PMID:15212297

  15. Relationship between lysosomal membrane destabilization and chemical body burden in eastern oysters (Crassostrea virginica) from Galveston Bay, Texas, USA.

    PubMed

    Hwang, Hyun-Min; Wade, Terry L; Sericano, Jose L

    2002-06-01

    Lysosomal destabilization was measured by using hemocytes of eastern oysters (Crassostrea virginica) collected along a chemical concentration gradient in Galveston Bay, Texas, USA. Results of the lysosomal response were compared to concentrations of organic compounds and trace elements in oyster tissue. Concentrations (on a dry-wt basis) ranged from 288 to 2,390 ng/g for polycyclic aromatic hydrocarbons (PAHs), 38 to 877 ng Sn/g for tri-n-butyltin (TBT), 60 to 562 ng/g for polyclorinated biphenyls (PCBs), and 7 to 71 ng/g for total DDT. Trace element concentrations (on a dry-wt basis) ranged from 1.1 to 4.0 microg/g for Cd, 105 to 229 microg/g for Cu, 212 to 868 microg/g for Al, and 1,200 to 8,180 microg/g for Zn. The percentage of destabilized lysosomes ranged from 34 to 81%. A significant positive correlation (p < 0.05) was observed between lysosomal destabilization and body burden of organic compounds (PAHs, PCBs, TBT, and chlorinated pesticides). No significant correlation was found between metal concentrations and lysosomal destabilization. Based on lysosomal destabilization, the study sites in Galveston Bay can be placed in one of three groups: healthy (Hanna Reef and Confederate Bay), moderately damaged (Offats Bayou and Todd's Dump), and highly damaged (Yacht Club and Ship Channel). Lysosomal destabilization that is consistent with toxic chemical body burdens supports previous observations that lysosomal membranes are damaged by toxic chemicals and indicates that this method can serve as an early screening tool to assess overall ecosystem health by using oysters. PMID:12069313

  16. Transcriptome response of the Pacific oyster (Crassostrea gigas) to infection with Vibrio tubiashii using cDNA AFLP differential display

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used qualitative complementary DNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) differential display analysis and real-time, quantitative PCR (RT-qPCR) to identify genes in the Pacific oyster Crassostrea gigas whose transcription either changes in response to exposure to a pathogenic bacter...

  17. PARASITIC AND SYMBIOTIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) AND MUD CRABS (PANOPEUS SPP.) FROM THE CALOOSAHATCHEE ESTUARY, FLORIDA, USA.

    EPA Science Inventory

    Volety, Aswani K., S. Greg Tolley and James T. Winstead. 2002. Parasitic and Symbiotic Fauna in Oysters (Crassostrea virginica) and Mud Crabs (Panopeus spp.) from the Caloosahatchee Estuary, Florida, USA (Abstract). Presented at the 4th International Conference on Molluscan Shell...

  18. Transcriptome profiling of selectively bred Pacific oyster Crassostrea gigas families that differ in tolerance of heat shock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sessile inhabitants of marine intertidal environments commonly face heat stress, an important component of summer mortality syndrome in the Pacific oyster Crassostrea gigas. Marker-aided selection programs would be useful for developing oyster strains that resist summer mortality; however, there i...

  19. RAPID TETRAZOLIUM DYE REDUCTION ASSAY TO ASSESS THE BACTERICIDAL ACTIVITY OF OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTES AGAINST VIBRIO PARAHAEMOLYTICUS

    EPA Science Inventory

    An assay was developed to assess the ability of oyster, Crassostrea virginica, hemocytes to kill the human pathogenic bacterium, Vibrio parahaemolyticus (ATCC 17802). Bacterial killing was estimated colorimetrically by the enzymatic reduction of a tetrazolium dye, 3-(4,5-dimethyl...

  20. CHANGES IN THE FREE AMINO ACID POOL DURING ENVIRONMENTAL STRESS IN THE GILL TISSUE OF THE OYSTER, 'CRASSOSTREA VIRGINICA'

    EPA Science Inventory

    The purpose of this study was to examine the FAA pool of the oyster Crassostrea virginica, during exposure to four stress-inducing agents to determine whether the amino acid pool might be used to identify agents inducing stress and to monitor stress phenomena. Three natural stres...

  1. Use of laboratory assays to predict subsequent growth and survival of Pacific oyster (Crassostrea gigas) families planted in coastal waters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selective breeding programs for improving Pacific oyster (Crassostrea gigas) stocks are expensive, labor-intensive, and rely on lengthy field trials that are subject to stochastic outbreaks of Summer Mortality Syndrome. Laboratory assays that identify and eliminate poor-performing families prior to...

  2. The Kumamoto oyster Crassostrea sikamea is neither rare nor threatened by hybridization in the northern Ariake Sea, Japan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The status of the Kumamoto oyster Crassostrea sikamea in its native Japan is uncertain because of a lack of information about its abundance and distribution and a suggestion that C. sikamea and the Pacific oyster C. gigas hybridize in the northern Ariake Sea. Furthermore, broodstock populations on ...

  3. PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI, IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS

    EPA Science Inventory

    The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994-Dec. 1995) of oysters, Crassostrea virginica, that set on an artificial reef located in the Piankatank River, Virginia, in Augus...

  4. Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves.

    PubMed

    Ngeve, Magdalene N; Van der Stocken, Tom; Menemenlis, Dimitris; Koedam, Nico; Triest, Ludwig

    2016-01-01

    Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites) in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL) is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC) corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC) presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate change

  5. Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves

    PubMed Central

    Ngeve, Magdalene N.; Van der Stocken, Tom; Menemenlis, Dimitris; Koedam, Nico; Triest, Ludwig

    2016-01-01

    Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites) in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL) is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC) corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC) presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate change

  6. Stress tolerance of a subtropical Crassostrea virginica population to the combined effects of temperature and salinity

    NASA Astrophysics Data System (ADS)

    Heilmayer, Olaf; Digialleonardo, Julian; Qian, Lianfen; Roesijadi, Guritno

    2008-08-01

    The combination of salinity and temperature has synergistic effects on virtually all aspects of the biology of estuarine organisms. Of interest were site-specific characteristics in the response of the eastern oyster, Crassostrea virginica, from the St. Lucie River Estuary to the interactive effects of temperature and salinity. This estuary, one of the largest on the central east coast of Florida, is strongly influenced by anthropogenic modifications due to management needs to control the patterns of freshwater flow in the St. Lucie River watershed. Crassostrea virginica is designated a valued ecosystem component for monitoring the health of this estuary. Our approach used a multidimensional response surface design to study the effects of temperature and salinity on sublethal measures of oyster performance: (1) body condition index as an overall indicator of bioenergetic status and (2) the RNA/DNA ratio as a biochemical indicator of cellular stress. The results showed that there was a greater ability to withstand extreme salinity conditions at lower temperatures. However, there were no site-specific attributes that differentiated the response of the St. Lucie Estuary population from populations along the distribution range. Condition index was a less variable response than the RNA/DNA ratio, and the final models for mean condition index and the RNA/DNA ratios explained 77.3 and 35.8% of the respective variances.

  7. INFECTION INTENSITY OF PERKINSUS MARINUS DISEASE IN CRASSOSTREA VIRGINICA (GMELIN, 1791) FROM THE GULF OF MEXICO MAINTAINED UNDER DIFFERENT LABORATORY CONDITIONS

    EPA Science Inventory

    A protozoan parasite, Perkinsus marinus, has been responsible for infection and mortality of eastern oysters, Crassostrea virginica, since before 1950. tudies on the course of infection intensity (incidence) in individual animals have been restricted by the need to sacrifice anim...

  8. The Presence of Histamine and a Histamine Receptor in the Bivalve Mollusc, Crassostrea virginica

    PubMed Central

    Harrison, Jarreau; LaFleur, Kisha; Mantone, Daniel; Boisette, Beatrix; Harris, Ave; Catapane, Edward J.; Carroll, Margaret A.

    2015-01-01

    Histamine, a biogenic amine, is a neurotransmitter in neurons and sensory receptors in invertebrates. Histamine has rarely been reported in bivalves. We used HPLC with pre-column derivatization using 2,3-naphthalenedicarboxaldehyde (NDA) as a fluorescent labeling agent to measure histamine in ganglia, and peripheral tissues of the oyster Crassostrea virginica. We also used Western Blot technique to look for the presence of a histamine receptor in the mantle rim. HPLC results found histamine present in ng amounts in both the cerebral and visceral ganglia, as well as the mantle rim and other peripheral tissues of C. virginica. The study confirms and quantifies histamine as an endogenous biogenic amine in C. virginica in the nervous system and innervated organs. Western Blot technique also identified a histamine H2-like receptor present in sensory tissue of the oyster's mantle rim. PMID:26120600

  9. Eastern oyster (Crassostrea virginica) δ15N as a bioindicator of nitrogen sources: Observations and modeling

    PubMed Central

    Fertig, B.; Carruthers, T.J.B.; Dennison, W.C.; Fertig, E.J.; Altabet, M.A.

    2013-01-01

    Stable nitrogen isotopes (δ15N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue δ15N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that δ15N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal δ15N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations. PMID:20381097

  10. Effect of cadmium body burdens in adult Crassostrea virginica on fecundity and viability of larvae

    SciTech Connect

    Zaroogian, G.E.; Morrison, G.

    1981-09-01

    Because marine bivalves in general and Crassostrea virginica in particular are good accumulators of metals, a study was performed to determine if embryos from parents with high concentrations of cadmium in soft tissues are more sensitive to cadmium toxicity than those from parents with low tissue cadmium concentrations. In addition, the study was designed to investigate the effect of selected cadmium treatments on larval growth. It was found that despite cadmium concentrations as high as 270 micrograms/gram dry weight in the total soft tissues, oysters spawned heavily. It was generally concluded that seawater cadmium concentrations of 5 micrograms/kg are not toxic to oyster embryos, but does cause enough stress to delay development into larvae.

  11. Integration of Vibrio vulnificus into Marine Aggregates and Its Subsequent Uptake by Crassostrea virginica Oysters

    PubMed Central

    Froelich, Brett; Ayrapetyan, Mesrop

    2013-01-01

    Marine aggregates are naturally forming conglomerations of larvacean houses, phytoplankton, microbes, and inorganics adhered together by exocellular polymers. In this study, we show in vitro that the bacterial pathogen Vibrio vulnificus can be concentrated into laboratory-generated aggregates from surrounding water. We further show that environmental (E-genotype) strains exhibit significantly more integration into these aggregates than clinical (C-genotype) strains. Experiments where marine aggregates with attached V. vulnificus cells were fed to oysters (Crassostrea virginica) resulted in greater uptake of both C and E types than nonaggregated controls. When C- and E-genotype strains were cocultured in competitive experiments, the aggregated E-genotype strains exhibited significantly greater uptake by oyster than the C-genotype strains. PMID:23263962

  12. Cytochemical characterization of yolk granule acid phosphatase during early development of the oyster Crassostrea gigas (Thunberg)

    NASA Astrophysics Data System (ADS)

    Wang, Yiyan; Sun, Hushan; Wang, Yanjie; Yan, Dongchun; Wang, Lei

    2015-03-01

    In this study, a cytochemical method and transmission electron microscopy was used to examine acid phosphatase activities of yolk granules throughout the early developmental stages of the Pacific oyster Crassostrea gigas. This study aimed to investigate the dynamic change of yolk granule acid phosphatase, and the mechanisms underlying its involvement in yolk degradation during the early developmental stages of molluscs. Three types of yolk granules (YGI, YGII, and YGIII) that differed in electron density and acid phosphatase reaction were identified in early cleavage, morula, blastula, gastrula, trochophore, and veliger stages. The morphological heterogeneities of the yolk granules were related to acid phosphatase activity and degrees of yolk degradation, indicating the association of acid phosphatase with yolk degradation in embryos and larvae of molluscs. Fusion of yolk granules was observed during embryogenesis and larval development of C. gigas. The fusion of YGI (free of acid phosphatase reaction) with YGII (rich in acid phosphatase reaction) could be the way by which yolk degradation is triggered.

  13. Modulation of Crassostrea virginica hemocyte reactive oxygen species production by Listonella anguillarum.

    PubMed

    Bramble, L; Anderson, R S

    1997-01-01

    Luminol- and lucigenin-augmented chemiluminescence (CL) were used to evaluate the ability of Listonella (formerly Vibrio) anguillarum to stimulate the production of reactive oxygen species (ROS) by Crassostrea virginica hemocytes. Whereas heat-killed L. anguillarum stimulated hemocyte CL in the lucigenin system, viable L. anguillarum did not. Neither viable nor heat-killed bacteria stimulated hemocyte production of luminol CL. Metabolically active L. anguillarum generated ROS, as indicated by luminol and lucigenin CL. It is proposed that bacterial catalase suppressed hemocyte-derived luminol CL. L. anguillarum, which possesses the antioxidant enzyme catalase, suppressed luminol CL generated by zymosan-stimulated hemocytes. Conversely, the catalase negative bacterium Carnobacterium piscicola had no effect on hemocyte-derived luminol CL elicited by zymosan. The inability of viable L. anguillarum to stimulate hemocyte ROS production, as measured by CL, does not support the proposed role for ROS in hemocyte-mediated bactericidal activity. PMID:9303272

  14. A Multi-module Approach to Calculation of Oyster ( Crassostrea virginica) Environmental Benefits

    NASA Astrophysics Data System (ADS)

    Cerco, Carl F.

    2015-08-01

    Environmental benefits are one of the motivations for management restoration of depleted bivalve populations. We describe a series of linked modules for benefits calculation. The modules include: oyster ( Crassostrea virginica) bioenergetics, materials transport via the tidal prism, and benefits quantification. Quantified benefits include carbon, nitrogen, and phosphorus removal and shell production. The modules are demonstrated through application to the Great Wicomico River, a tributary of Chesapeake Bay, USA. Oysters on seven reefs (total area 2.8 × 105 m2) are calculated to remove 15.2, 6.2, and 0.2 tons per annum of carbon, nitrogen, and phosphorus, respectively, from the Great Wicomico. Oyster mortality contributes 108 tons per annum dry weight shell to the reefs.

  15. Characterization of the mantle transcriptome in bivalves: Pecten maximus, Mytilus edulis and Crassostrea gigas.

    PubMed

    Yarra, Tejaswi; Gharbi, Karim; Blaxter, Mark; Peck, Lloyd S; Clark, Melody S

    2016-06-01

    The calcareous shells secreted by bivalve molluscs display diverse and species specific structural compositions, which indicates possible divergent biomineralization processes. Thus, studying multiple mollusc species will provide a more comprehensive understanding of shell formation. Here, the transcriptomes of the mantle tissues responsible for shell deposition were characterized in three commercially relevant bivalve species. Using high-throughput sequencing and bioinformatics tools, de novo transcriptome assemblies of mantle tissues were generated for the mussel Mytilus edulis, the oyster Crassostrea gigas and the scallop Pecten maximus. These transcriptomes were annotated, and contigs with similarity to proteins known to have shell formation roles in other species were identified. Comparison of the shell formation specific proteins in the three bivalves indicates the possibility of species specific shell proteins. PMID:27160853

  16. Bacteriophage as models for virus removal from Pacific oysters (Crassostrea gigas) during re-laying.

    PubMed Central

    Humphrey, T. J.; Martin, K.

    1993-01-01

    A study was undertaken to examine the feasibility of using naturally-occurring bacteriophages to assess the impact of re-laying on levels of viral contamination in Crassostrea gigas, the Pacific oyster. Two phages were chosen. One, male-specific (F+), was enumerated using Salmonella typhimurium. The other, a somatic phage, was detected using an, as yet, uncharacterized Escherichia coli. Investigations, using a variety of re-laying sites, demonstrated that numbers of F+ phage in oyster tissue declined more rapidly than those of somatic phage. For example, in oysters placed in commercially-used sea water ponds, F+ phage reached undetectable levels within 2-3 weeks, whereas somatic phage could still be detected 5 weeks after re-laying. The studies suggest that F+ phage may not be a suitable indicator for virus removal and that somatic phage may be better suited to this role. PMID:8405159

  17. A Glycoprotein in Shells of Conspecifics Induces Larval Settlement of the Pacific Oyster Crassostrea gigas

    PubMed Central

    Vasquez, Hebert Ely; Hashimoto, Kyotaro; Yoshida, Asami; Hara, Kenji; Imai, Chisato Chris; Kitamura, Hitoshi; Satuito, Cyril Glenn

    2013-01-01

    Settlement of larvae of Crassostrea gigas on shell chips (SC) prepared from shells of 11 different species of mollusks was investigated. Furthermore, the settlement inducing compound in the shell of C. gigas was extracted and subjected to various treatments to characterize the chemical cue. C. gigas larvae settled on SC of all species tested except on Patinopecten yessoensis and Atrina pinnata. In SC of species that induced C. gigas larvae to settle, settlement was proportionate to the amount of SC supplied to the larvae. When compared to C. gigas SC, all species except Crassostrea nippona showed lower settlement inducing activities, suggesting that the cue may be more abundant or in a more available form to the larvae in shells of conspecific and C. nippona than in other species. The settlement inducing activity of C. gigas SC remained intact after antibiotic treatment. Extraction of C. gigas SC with diethyl ether (Et2O-ex), ethanol (EtOH-ex), and water (Aq-ex) did not induce larval settlement of C. gigas larvae. However, extraction of C. gigas SC with 2N of hydrochloric acid (HCl-ex) induced larval settlement that was at the same level as the SC. The settlement inducing compound in the HCl-ex was stable at 100°C but was destroyed or degraded after pepsin, trypsin, PNGase F and trifluoromethanesulfonic acid treatments. This chemical cue eluted between the molecular mass range of 45 and 150 kDa after gel filtration and revealed a major band at 55 kDa on the SDS-PAGE gel after staining with Stains-all. Thus, a 55 kDa glycoprotein component in the organic matrix of C. gigas shells is hypothesized to be the chemical basis of larval settlement on conspecifics. PMID:24349261

  18. Development of the analysis of fecal stanols in the oyster Crassostrea gigas and identification of fecal contamination in shellfish harvesting areas.

    PubMed

    Harrault, Loïc; Jardé, Emilie; Jeanneau, Laurent; Petitjean, Patrice

    2014-06-01

    The objective of this work was to study the effects of washing and purification steps on qualitative and quantitative analysis of fecal stanols in the oyster Crassostrea gigas using either single or a combination of lipid purification steps on silica gel or aminopropyl bonded silica gel (NH2) or a washing step. Among the three analytical pathways compared, the two including water extraction or NH2 purification did not lead to higher recoveries and decreased repeatabilities of extractions compared to the single purification on silica gel. This latter led to similar recoveries (ca. 80%) and repeatabilities (ca. 10%) for both spiked standards (coprostanol and sitostanol). This analytical pathway has been applied to oysters collected in a harvesting area in Brittany (France) where fecal contaminations are important and allowed to quantify eight stanols in oysters. The relative proportions of fecal stanols of these oysters were combined with principal component analysis in order to investigate the usefulness of their stanol fingerprints to record a fecal contamination and to distinguish its source between human, porcine and bovine contaminations. Oysters non-fecally contaminated by Escherichia coli did not present specific stanol fingerprints while oysters fecally contaminated had a bovine fingerprint, suggesting a contamination of these samples by bovine sources. As a consequence, the method developed here allows the use of stanol fingerprints of oysters as a microbial source tracking tool that can be applied to shellfish harvesting areas subjected to fecal contaminations in order to identify the different sources of contamination and improve watershed management. PMID:24771549

  19. US Mussel Watch 1976-1978: an overview of the trace-metal, DDE, PCB, hydrocarbon, and artificial radionuclide data. [Mytilus edulis, M. californianus, Crassostrea sp

    SciTech Connect

    Farrington, J.W.; Goldberg, E.D.; Risebrough, R.W.; Martin, J.H.; Bowen, V.T.

    1983-08-01

    Data are presented for trace metals, polychlorinated biphenyls (PCBs), aromatic hydrocarbons and /sup 239/ /sup 240/Pu in Mytilus edulis, M. californianus, and Crassostrea sp. collected in the US Mussel Watch program in 1976-1978 from 62 locations on the US east and west coasts. General similarities in geographical distributions of concentrations were present in all 3 years with at least an order of magnitude elevation of concentrations of Pb, PCBs, and fossil fuel hydrocarbons in bivalves sampled near the larger urban areas. Elevated Cd and /sup 239/ /sup 240/Pu concentrations in bivalves from the central California coast are apparently related to enrichments of Cd and nuclear weapons testing fallout /sup 239/ /sup 240/Pu in intermediate depth water of the North Pacific and upwelling of this water associated with the California Current system. Data have revealed no evidence of local or regional systematic elevations of environmental concentrations of /sup 239/ /sup 240/Pu as a result of effluent releases from nuclear power reactors.

  20. Physiological response and resilience of early life-stage Eastern oysters (Crassostrea virginica) to past, present and future ocean acidification

    PubMed Central

    Gobler, Christopher J.; Talmage, Stephanie C.

    2014-01-01

    The Eastern oyster, Crassostrea virginica (Gmelin, 1791), is the second most valuable bivalve fishery in the USA and is sensitive to high levels of partial pressure of CO2 (pCO2). Here we present experiments that comprehensively examined how the ocean's past, present and projected (21st and 22nd centuries) CO2 concentrations impact the growth and physiology of larval stages of C. virginica. Crassostrea virginica larvae grown in present-day pCO2 concentrations (380 μatm) displayed higher growth and survival than individuals grown at both lower (250 μatm) and higher pCO2 levels (750 and 1500 μatm). Crassostrea virginica larvae manifested calcification rates, sizes, shell thicknesses, metamorphosis, RNA:DNA ratios and lipid contents that paralleled trends in survival, with maximal values for larvae grown at 380 μatm pCO2 and reduced performance in higher and lower pCO2 levels. While some physiological differences among oysters could be attributed to CO2-induced changes in size or calcification rates, the RNA:DNA ratios at ambient pCO2 levels were elevated, independent of these factors. Likewise, the lipid contents of individuals exposed to high pCO2 levels were depressed even when differences in calcification rates were considered. These findings reveal the cascading, interdependent impact that high CO2 can have on oyster physiology. Crassostrea virginica larvae are significantly more resistant to elevated pCO2 than other North Atlantic bivalves, such as Mercenaria mercenaria and Argopecten irradians, a finding that may be related to the biogeography and/or evolutionary history of these species and may have important implications for future bivalve restoration and aquaculture efforts. PMID:27293625

  1. Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides

    NASA Astrophysics Data System (ADS)

    Harzhauser, Mathias; Djuricic, Ana; Mandic, Oleg; Neubauer, Thomas A.; Zuschin, Martin; Pfeifer, Norbert

    2016-02-01

    We present the first analysis of population structure and cohort distribution in a fossil oyster shell bed based on 1121 shells of the giant oyster Crassostrea gryphoides (von Schlotheim, 1813). Data derive from terrestrial laser scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around a few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale. Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of ˜ 150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.

  2. A new non-indigenous Crassostrea species in Southwest Atlantic salt marshes affects mortality of the cordgrass Spartina alterniflora

    NASA Astrophysics Data System (ADS)

    Lomovasky, Betina J.; Alvarez, Graciela; Addino, Mariana; Montemayor, Diana I.; Iribarne, Oscar

    2014-07-01

    Biological invasions in marine and coastal systems may produce new trophic and nontrophic interactions influencing the structure of the invaded community. In the intertidal salt marshes of Samborombón Bay (36°19‧20″S, 56°46‧26″W; mouth of La Plata River; Argentina), there is a new non-indigenous oyster species, Crassostrea sp., which settles on the dominant smooth cordgrass Spartina alterniflora. Here, we analyzed if the oyster affects S. alterniflora. Sampling showed that density of live plant was similar across intertidal levels, but there were higher density of dead plant stems at low intertidal levels. This pattern coincides with higher density and larger shell size of Crassostrea sp. at the low intertidal where oysters are attached to the basal part of the plant stems. An experiment manipulating oysters attached to S. alterniflora stems and oyster mimics shows that Crassostrea sp. can indeed increase mortality of S. alterniflora. The negative effect of bivalves on plant could be because several oysters settle around the Spartina stem, and by growing during the year, strangle the plants increasing their mortality rate. Together, all these evidences strongly suggest that these non-indigenous oysters can control the lower intertidal level of plant distribution in this system.

  3. Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides

    NASA Astrophysics Data System (ADS)

    Harzhauser, M.; Djuricic, A.; Mandic, O.; Neubauer, T. A.; Zuschin, M.; Pfeifer, N.

    2015-09-01

    We present the first analysis of population structure and cohort distribution in a fossil oyster reef based on more than 1121 shells of the giant oyster Crassostrea gryphoides (Schlotheim, 1813). Data derive from Terrestrial Laser Scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale. Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of ~ 150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.

  4. A shell concentration of the Middle Miocene Crassostrea gryphoides (Schlotheim, 1813) from Siwa Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El-Sabbagh, Ahmed M.; El Hedeny, Magdy M.

    2016-08-01

    A concentration of heavy, thick-shelled, large-sized, and elongated population of the oyster Crassostrea gryphoides (Schlotheim, 1813) was recorded in shallow-marine deposits of the basal Oasis Member of the Middle Miocene Marmarica Formation exposed at Siwa Oasis, Egypt. The oyster assemblage is resedimented as a lens-shaped bank up to 80-100 cm thick and about 220 m long. Crassostrea gryphoides specimens are embedded in a yellowish green, soft marl matrix. This is the first documented occurrence of this lens at Siwa Oasis. The lensoid structure is bounded by a lower marl and an upper shale beds of about 2 m and 1.5 m thick, respectively. Assemblage within this lens is characterized by extreme variations of Crassostrea gryphoides, forming an almost monotypic assemblage. The shell packing was dense (shell percentages higher than 75%) at the base and the center of the lens, whereas it exhibits loose packing at the top and right and left sides of the lens (shell percentage less than 15%). Valves are poorly sorted and randomly orientated (both in surface and cross section views). Encrustation and bioerosion have observed on both sides of the left and right valves. The relatively limited varieties of encrusters together with moderate frequency of borings indicate moderate to high sedimentation rate. On the other hand, the low abundance of fragmented and abraded shells indicates good preservation and minimal transport. The studied lens concentration is interpreted as proximal tempestites assemblage.

  5. Key metabolic pathways involved in xenobiotic biotransformation and stress responses revealed by transcriptomics of the mangrove oyster Crassostrea brasiliana.

    PubMed

    Lüchmann, Karim H; Clark, Melody S; Bainy, Afonso C D; Gilbert, Jack A; Craft, John A; Chipman, J Kevin; Thorne, Michael A S; Mattos, Jacó J; Siebert, Marília N; Schroeder, Declan C

    2015-09-01

    The Brazilian oyster Crassostrea brasiliana was challenged to three common environmental contaminants: phenanthrene, diesel fuel water-accommodated fraction (WAF) and domestic sewage. Total RNA was extracted from the gill and digestive gland, and cDNA libraries were sequenced using the 454 FLX platform. The assembled transcriptome resulted in ̃20,000 contigs, which were annotated to produce the first de novo transcriptome for C. brasiliana. Sequences were screened to identify genes potentially involved in the biotransformation of xenobiotics and associated antioxidant defence mechanisms. These gene families included those of the cytochrome P450 (CYP450), 70kDa heat shock, antioxidants, such as glutathione S-transferase, superoxide dismutase, catalase and also multi-drug resistance proteins. Analysis showed that the massive expansion of the CYP450 and HSP70 family due to gene duplication identified in the Crassostrea gigas genome also occurred in C. brasiliana, suggesting these processes form the base of the Crassostrea lineage. Preliminary expression analyses revealed several candidates biomarker genes that were up-regulated during each of the three treatments, suggesting the potential for environmental monitoring. PMID:26186662

  6. Protective effect of marine mangrove Rhizophora apiculata on acetic acid induced experimental colitis by regulating anti-oxidant enzymes, inflammatory mediators and nuclear factor-kappa B subunits.

    PubMed

    V, Vinod Prabhu; C, Guruvayoorappan

    2014-01-01

    Ulcerative colitis is a disease that causes inflammation and ulcer in the lining of the large intestine. In this study we investigate the effect of Rhizophora apiculata (R. apiculata) on acetic acid induced colitis in mouse model. Experimental animals were randomized into four groups: normal untreated, colitis control, R. apiculata treated group and sulfasalazine treated group. R. apiculata significantly (p<0.01) decreased macroscopic score and wet weight of damaged colon compared to colitis control. This effect was confirmed biochemically by significant (p<0.01) reduction of colitis associated increase in myeloperoxidase activity. R. apiculata significantly (p<0.05) increased anti-oxidant enzymes such as superoxide dismutase (SOD) and glutathione (GSH) levels compared to colitis control. R. apiculata significantly (p<0.01) reduced lipid peroxides (LPO), nitric oxide (NO) and inflammatory mediators such as myeloperoxidase (MPO), lactate dehydrogenase (LDH), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) expressions compared to colitis control. R. apiculata treatment significantly (p<0.01) inhibits the translocation of NF-kB p65 and p50 subunits. Taken together these findings suggest that R. apiculata prevents acetic acid induced colitis in experimental mouse model and may serve as an excellent anti-oxidant and anti-inflammatory agent that could potentially be useful as a (natural) therapy for inflammatory bowel disease (IBD). PMID:24269623

  7. The categorization and mutual modulation of expanded MyD88s in Crassostrea gigas.

    PubMed

    Xin, Lusheng; Wang, Mengqiang; Zhang, Huan; Li, Meijia; Wang, Hao; Wang, Lingling; Song, Linsheng

    2016-07-01

    MyD88 serves as a critical cytosolic adaptor mediating activation of NF-κB in innate immunity. It has been found that there is a considerable expansion of MyD88 in Crassostrea gigas. In the present study, four typical MyD88 genes in Crassostrea gigas (CgMyD88-A to CgMyD88-D) were successfully cloned and their potential functions were investigated together with another two known ones (CgMyD88-T1 and CgMyD88-T2). Multiple alignments revealed that CgMyD88-B and CgMyD88-C remained the conserved DD and TIR domains, while there was a significant variation of E51Q in the DD of CgMyD88-A, and some variations in both DD and TIR domains of CgMyD88-D, respectively. Both truncated CgMyD88-T1 and CgMyD88-T2 lacked Box II in their only TIR domains. Expression pattern analysis showed that CgMyD88-B and CgMyD88-C genes possessed higher expression in normal tissues, compared with the other four. When oysters were under bacteria challenge, CgMyD88-B, CgMyD88-C, CgMyD88-T1 and CgMyD88-T2 were firstly induced, while CgMyD88-A and CgMyD88-D were suppressed. Dual luciferase reporter assays showed that CgMyD88-B and CgMyD88-C could promote the activation of NF-κB signaling pathway, while the other four CgMyD88 genes failed or even suppressed the activities of CgMyD88-B and CgMyD88-C on the activation of NF-κB signaling. It was deduced that after oysters were challenged by bacteria, CgMyD88-B and CgMyD88-C could rapidly and efficiently activate NF-κB signaling pathway to elicit anti-pathogen responses before suppressor CgMyD88 genes (CgMyD88-T1 and CgMyD88-T2) exceeding their expression level. These results suggested that there was mutual modulation of expanded CgMyD88 genes on activating NF-κB signaling pathway in oyster C. gigas. PMID:27074442

  8. Chronic effects of non-weathered and weathered crude oil and dispersant associated with the Deepwater Horizon incident on development of larvae of the eastern oyster, Crassostrea virginica.

    PubMed

    Langdon, Chris J; Stefansson, Emily S; Pargee, Suzanne M; Blunt, Susanna M; Gage, Susan J; Stubblefield, William A

    2016-08-01

    The present study examined the effects of chronic exposure of eastern oyster (Crassostrea virginica) larvae to the water-accommodated fractions of fresh and weathered oils collected from the Deepwater Horizon incident, with and without additions of the dispersant Corexit 9500A, as well as to solutions of Corexit alone. Both shell growth of larvae exposed to test materials for a period of 10 d and larval settlement after 28 d of exposure were the most sensitive endpoints, with the 10-d growth endpoint being less variable among replicates. Growth and settlement endpoints were more sensitive than larval survival and normal development after 10 d and 28 d. Acute-to-chronic ratios calculated in the present study suggest that acute toxicities of oils and dispersant for oysters are not predictive of chronic effect levels for growth and settlement; therefore, chronic bioassays are necessary to assess these sublethal effects, in addition to standard 48-h acute toxicity tests. Comparison of 10% effective concentration (EC10) values for chronic 10-d growth and 28-d settlement endpoints with concentrations of total polycyclic aromatic hydrocarbons and dipropylene glycol n-butyl ether (a marker for Corexit) in seawater samples, collected during and after the Deepwater Horizon incident, indicated it was unlikely that elevated concentrations of water-soluble fractions of oil and dispersant in the nearshore environment had significant adverse effects on the growth and settlement of eastern oyster larvae. Environ Toxicol Chem 2016;35:2029-2040. © 2016 SETAC. PMID:26749151

  9. Post-glacial expansion and population genetic divergence of mangrove species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican coast.

    PubMed

    Sandoval-Castro, Eduardo; Dodd, Richard S; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans. PMID:24699389

  10. Mangrove plant, Rhizophora mucronata (Lamk, 1804) mediated one pot green synthesis of silver nanoparticles and its antibacterial activity against aquatic pathogens

    PubMed Central

    2012-01-01

    Background Biosynthesis of nanoparticles has received increasing attention due to the growing need to develop safe, time-effective and environmentally friendly technologies for nano-materials synthesis. This paper reports the one pot green synthesis of silver nanoparticles (AgNPs) using the leaf bud extract of a mangrove plant, Rhizophora mucronata and their antimicrobial effects against aquatic pathogens. Highly stable AgNPs were synthesized by treating the mangrove leaf bud extract with aqueous silver nitrate solution at 15 psi pressure and 121°C for 5 minutes. Results The biosynthesized AgNPs were characterized by UV-visible spectrum, at 426 nm. The X-Ray Diffraction (XRD) pattern revealed the face-centered cubic geometry of AgNPs. Fourier Transform Infra Red (FTIR) spectroscopic analysis was carried out to identify the possible biomolecules responsible for biosynthesis of AgNPs from the leaf bud extract. The size and shape of the well-dispersed AgNPs were documented with the help of High Resolution Transmission Electron Microscopy (HRTEM) with a diameter ranged from 4 to 26 nm. However a maximum number of particles were observed at 4 nm in size. The antibacterial effects of AgNPs were studied against aquatic pathogens Proteus spp., Pseudomonas fluorescens and Flavobacterium spp., isolated from infected marine ornamental fish, Dascyllus trimaculatus. Conclusion This study reveals that the biosynthesized AgNPs using the leaf bud extract of a mangrove plant (R. mucronata) were found equally potent to synthetic antibiotics. The size of the inhibition zone increases when the concentration of the AgNPs increased and varies according to species. PMID:22608057

  11. Influences of salinity and shade on seedling photosynthesis and growth of two mangrove species, Rhizophora mangle and Bruguiera sexangula, introduced to Hawaii

    USGS Publications Warehouse

    Krauss, K.W.; Allen, J.A.

    2003-01-01

    Rhizophora mangle was first introduced to Hawaii in 1902 to promote shoreline stabilization. Intertidal competition with native and introduced salt marsh species was low, and beyond the early 1920s, mangrove forests expanded rapidly. An additional mangrove species, Bruguiera sexangula, was introduced in 1922 and currently co-occurs with R. mangle in only a few stands on the north shore and windward sides of Oahu. Where the two species overlap, R. mangle, having colonized intertidal zones first, forms nearly monospecific forest stands. To determine why R. mangle remains the dominant mangrove, we initiated a greenhouse study to compare seedling growth and photosynthetic light response of both species growing at two light levels and contrasting salinity regimes (2, 10, 32 PSU). The asymptotic nature of B. sexangula' s assimilation response is indicative of stomatal regulation, whereas only light level appears to regulate photosynthesis in R. mangle. Shifts in patterns of biomass allocation and physiological response indicate two contrasting strategies relative to sunlight and salinity. B. sexangula's strategy is characterized by slow growth with little variation under favorable conditions and morphological plasticity under stressful conditions, which allows for adjustments in carbon gain efficiency (morphological strategy). On the other hand, R. mangle's strategy involves faster growth under a wide range of environmental conditions with physiological enhancement of carbon assimilation (physiological strategy). Low salinity combined with reduced light, or simply low sunlight alone, appears to favor R. mangle and B. sexangula equally. High salinity places greater, but not overwhelming, stress on B. sexangula seedlings, but tends to favor R. mangle at higher light levels.

  12. Post-Glacial Expansion and Population Genetic Divergence of Mangrove Species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican Coast

    PubMed Central

    Sandoval-Castro, Eduardo; Dodd, Richard S.; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans. PMID:24699389

  13. Epizootiology of Perkinsus sp. inCrassostrea gasar oysters in polyculture with shrimps in northeastern Brazil.

    PubMed

    da Silva, Patricia Mirella; Costa, Carolina Pereira; de Araújo, Jaíse Paiva Bragante; Queiroga, Fernando Ramos; Wainberg, Alexandre Alter

    2016-01-01

    Bivalve culture is of considerable economic and social interest in northeastern (NE) Brazil. The polyculture is an alternative approach to traditional monoculture for reducing the environmental impact of shrimp farming and improving oyster culture. Perkinsus marinus and Perkinsus olseni were found infecting oysters in NE Brazil and can threaten oyster production. This study evaluated Perkinsus spp. occurrence in Crassostrea gasar during all production stages. Oyster spats were produced in a hatchery and grown in shrimp ponds in Rio Grande do Norte state. Perkinsus spp. were surveyed by Ray's fluid thioglycollate medium and confirmed by polymerase chain reaction. Prevalence and intensity of infection were determined in oysters until they reached 7 cm. Results showed that the broodstock was already infected by Perkinsus (60%), but the derived spats were Perkinsus-free. Oyster spats acquired Perkinsus infection when transferred to ponds. The prevalence gradually increased in the seven months following placement in ponds (73%), and then decreased to 17% by the tenth month. The infections were initially mild, but intensity increased at the final growth stage. In conclusion, it is possible to produce Perkinsus-free C. gasar oyster spats from infected broodstock, and their culture in shrimp ponds is feasible. PMID:27007244

  14. Immune response and mechanical stress susceptibility in diseased oysters, Crassostrea virginica.

    PubMed

    Roberts, Steven B; Sunila, Inke; Wikfors, Gary H

    2012-01-01

    Eastern oysters, Crassostrea virginica, naturally infected with the parasite Perkinsus marinus were subjected to a mechanical stress by centrifugation, and immune parameters, pathological conditions, and gene expression of selected transcripts were compared to uninfected controls. Immune parameters were assessed by flow cytometry, pathology and parasites by histotechnology and fluid thioglycollate assays, and gene expression by quantitative RT-PCR. Irrespective of mechanical stress, an increased number of hemocytes were observed in P. marinus-infected oysters that corresponded to increased expression of genes that have been shown to be involved in inflammation and apoptosis, two processes associated with regulating immune cell populations. Mechanically stressed, diseased oysters showed histological gill abnormalities and aggregations of hemocytes in tissues not seen in stressed, uninfected oysters. Expression of a high-mobility group protein and hemocyte phagocytosis were significantly upregulated upon mechanical stress only in uninfected oysters. The results of this study demonstrate the role of inflammation in the oyster immune response including possible underlying molecular mechanisms. Furthermore, this study highlights the importance of considering mechanical stressors when characterizing oyster immune function. PMID:21853237

  15. Stress tolerance of a subtropical Crassostrea virginica population to the combined effects of temperature and salinity

    SciTech Connect

    Heilmayer, Olaf; DiGialleonardo, Julian J.; Qian, Lianfen; Roesijadi, Guritno

    2008-08-10

    The combination of salinity and temperature has synergistic effects on virtually all aspects of the biology of estuarine organisms. Of interest were site-specific characteristics in the response of the eastern oyster, Crassostrea virginica, from the St. Lucie River Estuary to the interactive effects of temperature and salinity. This estuary, one of the largest on the central east coast of Florida, is strongly influenced by anthropogenic modifications due to management needs to control the patterns of freshwater flow in the St. Lucie River watershed. C. virginica is designated a valued ecosystem component for monitoring the health of this estuary. Our approach used a multidimensional response surface design to study the effects of temperature and salinity on sublethal measures of oyster performance: (1) body condition index as an overall indicator of bioenergetic status and (2) the RNA/DNA ratio as a biochemical indicator of cellular stress. The results showed that there was a greater ability to withstand extreme salinity conditions at lower temperatures. However, there were no site-specific attributes that differentiated the response of the St. Lucie Estuary population from populations along the distribution range. Condition index was a less variable response than the RNA/DNA ratio, and the final models for mean condition index and the RNA:DNA ratios explained 77.3% and 35.8% of the respective variances.

  16. High mobility group protein DSP1 negatively regulates HSP70 transcription in Crassostrea hongkongensis.

    PubMed

    Miao, Zongyu; Xu, Delin; Cui, Miao; Zhang, Qizhong

    2016-06-10

    HSP70 acts mostly as a molecular chaperone and plays important roles in facilitating the folding of nascent peptides as well as the refolding or degradation of the denatured proteins. Under stressed conditions, the expression level of HSP70 is upregulated significantly and rapidly, as is known to be achieved by various regulatory factors controlling the transcriptional level. In this study, a high mobility group protein DSP1 was identified by DNA-affinity purification from the nuclear extracts of Crassostrea hongkongensis using the ChHSP70 promoter as a bait. The specific interaction between the prokaryotically expressed ChDSP1 and the FITC-labeled ChHSP70 promoter was confirmed by EMSA analysis. ChDSP1 was shown to negatively regulate ChHSP70 promoter expression by Luciferase Reporter Assay in the heterologous HEK293T cells. Both ChHSP70 and ChDSP1 transcriptions were induced by either thermal or CdCl2 stress, while the accumulated expression peaks of ChDSP1 were always slightly delayed when compared with that of ChHSP70. This indicates that ChDSP1 is involved, very likely to exert its suppressive role, in the recovery of the ChHSP70 expression from the induced level to its original state. This study is the first to report negative regulator of HSP70 gene transcription, and provides novel insights into the mechanisms controlling heat shock protein expression. PMID:27154224

  17. Extraction and Identification of the Pigment in the Adductor Muscle Scar of Pacific Oyster Crassostrea gigas.

    PubMed

    Hao, Shixin; Hou, Xin; Wei, Lei; Li, Jian; Li, Zhonghu; Wang, Xiaotong

    2015-01-01

    In this study, UV (ultraviolet) and IR (infrared radiation) spectral analysis were integrated to identify the pigment in the adductor muscle scar of the Pacific oyster Crassostrea gigas. The pigment was extracted from the adductor muscle scars of cleaned oyster shells that were pulverized, hydrolyzed in hot hydrochloric acid, purified with diethyl ether, and dissolved in 0.01 mL/L NaOH. The maximum absorption of the pigment in the UV absorption spectrum within the range of 190-500 nm was observed between 210-220 nm. The UV absorbance decreased with increasing wavelength which was consistent with the UV spectral absorption characteristics of melanin. In addition, Fourier transform infrared spectroscopy scanning revealed characteristic absorption peaks that emerged near 3440 cm-1 and 1630 cm-1, which was consistent with infrared scanning features of eumelanin (a type of melanin). This study has demonstrated for the first time that the pigment in the adductor muscle scar of the Pacific oyster is melanin, hinting that the adductor muscle could be another organ pigmenting the mollusc shell with melanin other than mantle. PMID:26555720

  18. Changes in protein expression of pacific oyster Crassostrea gigas exposed in situ to urban sewage.

    PubMed

    Flores-Nunes, Fabrício; Gomes, Tânia; Company, Rui; Moraes, Roberta R M; Sasaki, Silvio T; Taniguchi, Satie; Bicego, Márcia C; Melo, Cláudio M R; Bainy, Afonso C D; Bebianno, Maria J

    2015-11-01

    The composition and concentration of substances in urban effluents are complex and difficult to measure. These contaminants elicit biological responses in the exposed organisms. Proteomic analysis is a powerful tool in environmental toxicology by evidencing alterations in protein expression due to exposure to contaminants and by providing a useful framework for the development of new potential biomarkers. The aim of this study was to determine changes in protein expression signatures (PES) in the digestive gland of oysters Crassostrea gigas transplanted to two farming areas (LIS and RIB) and to one area contaminated by sanitary sewage (BUC) after 14 days of exposure. This species is one of the most cultivated molluscs in the world. The identified proteins are related to the cytoskeleton (CKAP5 and ACT2), ubiquitination pathway conjugation (UBE3C), G protein-coupled receptor and signal transduction (SVEP1), and cell cycle/division (CCNB3). CKAP5 showed higher expression in oysters kept at BUC in comparison with those kept at the farming areas, while ACT2, UBE3C, SVEP1, and CCNB3 were suppressed. The results suggest that these changes might lead to DNA damage, apoptosis, and interference with the immune system in oyster C. gigas exposed to sewage and give initial information on PES of C. gigas exposed to sanitary sewage, which can subsequently be useful in the development of more sensitive tools for biomonitoring coastal areas, particularly those devoted mainly to oyster farming activities. PMID:25398216

  19. Microsatellite variation in the oyster Crassostrea plicatula along the coast of China

    NASA Astrophysics Data System (ADS)

    Yu, Hong; Li, Qi; Yu, Ruihai

    2008-11-01

    Genetic diversity and differentiation of the oyster Crassostrea plicatula populations from China’s coast were studied based on seven microsatellite loci. All loci showed high polymorphism for all five C. plicatula populations, with an average number of allele per locus of 19.3 27.9 and an average expected heterozygosity of 0.889 0.952. Significant departures from Hardy-Weinberg equilibrium and deficits of heterozygotes were observed over most populations at each locus, which were fully explained by null alleles. Microsatellite analysis revealed significant subdivision in the C. plicatula populations. According to the neighbor-joining tree constructed on the basis of the D A distance, the five populations fell into three regional groups, showing a relatively homogeneous genetic structure in geographically close populations. Assignation tests correctly assigned high percentages of individuals to their original populations and groups, and also confirmed the existence of genetic differentiation among C. plicatula populations. The results obtained in this study will facilitate the formulation of appropriate fisheries management programs, stock identification and conservation of biodiversity for the species.

  20. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

    NASA Astrophysics Data System (ADS)

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-05-01

    The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met5]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met5]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors.

  1. Phylogeny of forkhead genes in three spiralians and their expression in Pacific oyster Crassostrea gigas

    NASA Astrophysics Data System (ADS)

    Yang, Mei; Xu, Fei; Liu, Jun; Que, Huayong; Li, Li; Zhang, Guofan

    2014-11-01

    The Fox genes encode a group of transcription factors that contain a forkhead domain, which forms a structure known as a winged helix. These transcription factors play a crucial role in several key biological processes, including development. High-degree identity in the canonical forkhead domain has been used to divide Fox proteins into 23 families (FoxA to FoxS). We surveyed the genome of three spiralians, the oyster Crassostrea gigas, the limpet Lottia gigantea, and the annelid Capitella teleta. We identified 25 C. gigas fox genes, 21 L. gigantea fox genes, and 25 C. teleta fox genes. The C. gigas fox and L. gigantea fox genes represented 19 of the 23 families, whereas FoxI, Q1, R, and S were missing. The majority of the Fox families were observed within the C. teleta fox genes, with the exception of FoxR and S. In addition, the foxAB-like gene, foxY-like gene, and foxH gene were also present in the three genomes. The conserved FoxC-FoxL1 cluster, observed in mammals, was also found in C. gigas. The diversity of temporal expression patterns observed across the developmental process implies the C. gigas fox genes exert a wide range of functions. Further functional studies are required to gain insight into the evolution of Fox genes in bilaterians.

  2. Distinct immune responses of juvenile and adult oysters (Crassostrea gigas) to viral and bacterial infections.

    PubMed

    Green, Timothy J; Vergnes, Agnes; Montagnani, Caroline; de Lorgeril, Julien

    2016-01-01

    Since 2008, massive mortality events of Pacific oysters (Crassostrea gigas) have been reported worldwide and these disease events are often associated with Ostreid herpesvirus type 1 (OsHV-1). Epidemiological field studies have also reported oyster age and other pathogens of the Vibrio genus are contributing factors to this syndrome. We undertook a controlled laboratory experiment to simultaneously investigate survival and immunological response of juvenile and adult C. gigas at different time-points post-infection with OsHV-1, Vibrio tasmaniensis LGP32 and V. aestuarianus. Our data corroborates epidemiological studies that juveniles are more susceptible to OsHV-1, whereas adults are more susceptible to Vibrio. We measured the expression of 102 immune-genes by high-throughput RT-qPCR, which revealed oysters have different transcriptional responses to OsHV-1 and Vibrio. The transcriptional response in the early stages of OsHV-1 infection involved genes related to apoptosis and the interferon-pathway. Transcriptional response to Vibrio infection involved antimicrobial peptides, heat shock proteins and galectins. Interestingly, oysters in the later stages of OsHV-1 infection had a transcriptional response that resembled an antibacterial response, which is suggestive of the oyster's microbiome causing secondary infections (dysbiosis-driven pathology). This study provides molecular evidence that oysters can mount distinct immune response to viral and bacterial pathogens and these responses differ depending on the age of the host. PMID:27439510

  3. Screening and selection of stress resistant Lactobacillus spp. isolated from the marine oyster (Crassostrea gigas).

    PubMed

    Lee, Hae-In; Kim, Min Hee; Kim, Kwan Young; So, Jae-Seong

    2010-10-01

    We attempted to isolate Lactobacillus spp. from the marine oyster (Crassostrea gigas) and select stress resistant strains for development of a future marine aquaculture feed adjuvant. A total of 83 lactobacilli strains were isolated from oyster. They were all Gram-positive, rod-shaped and catalase-negative. By performing a stress resistance assay, we selected eighteen isolates. Based on 16S rRNA gene sequencing, Lactobacillus paracasei was the most prevalent species among the selected isolates. The in vitro antagonistic effect of the selected strains against fish pathogens was assayed by measurement of inhibition diameters. Except for MH44, MH51, MH53 and MH62, most of the isolates showed inhibition of Vibrio alginolyticus and Vibrio proteolyticus (diameters over 15 mm). Lactobacillus rhamnosus MH22 was selected as the most stress resistant strain showing the MICs of 1.8 M NaCl, 14% ethanol and 0.014% hydrogen peroxide. L. rhamnosus MH22 isolated from oyster has a potential to be applied as a microbial feed adjuvant for marine aquaculture. PMID:20633689

  4. Essential Fatty Acid Assimilation and Synthesis in Larvae of the Bivalve Crassostrea gigas.

    PubMed

    da Costa, Fiz; Robert, René; Quéré, Claudie; Wikfors, Gary H; Soudant, Philippe

    2015-05-01

    Essential fatty acids (EFA) are important for bivalve larval survival and growth. The purpose of this study was to quantitatively assess for the first time through a mass-balance approach dietary EFA incorporation and synthesis within Crassostrea gigas larvae. A first experiment was carried out using two microalgae, Tisochrysis lutea (T) and Chaetoceros neogracile (Cg), as mono- and bi-specific diets. A second experiment using a similar design was performed to confirm and extend the results obtained in the first. Flow-through larval rearing was used for accurate control of food supply and measurement of ingestion. Non-methylene-interrupted fatty acids were synthetized from precursors supplied in the diet: 16:1n-7 and 18:1n-9, mediated by Δ5 desaturase. Moreover, this Δ5 desaturase presumably allowed larvae to convert 20:3n-6 and 20:4n-3 to 20:4n-6 and 20:5n-3, respectively, when the product EFA were poorly or not supplied in the diet, as when larvae were fed T exclusively. Under our experimental conditions, none of the diets induced 22:6n-3 synthesis; however, 22:6n-3 incorporation into larval tissues occurred selectively under non-limiting dietary supply to maintain optimal levels in the larvae. This combination of flow-through larval rearing and biochemical analysis of FA levels could be applied to additional dietary experiments to precisely define optimal levels of EFA supply. PMID:25771891

  5. Suppression of chemiluminescence of eastern oyster (Crassostrea virginica) hemocytes by the protozoan parasite Perkinsus marinus.

    PubMed

    Volety, A K; Chu, F L

    1995-01-01

    Experiments were conducted to determine the ability of the protistan parasite, Perkinsus marinus, to inhibit chemiluminescence of hemocytes from the eastern oyster, Crassostrea virginica. Luminol-enhanced chemiluminescence (CL) was used to measure the production of reactive oxygen intermediates (ROI) generated by oyster hemocytes using zymosan as a stimulant. To determine whether P. marinus suppresses ROI evoked from zymosan-stimulated hemocytes, live or heat killed P. marinus in filtered estuarine water (YRW) (salinity = 20 ppt) were added to (1) zymosan-stimulated hemocytes after CL reached its peak, or (2) hemocytes at the same time as zymosan, and reduction of CL responses were recorded. In both tests, controls received only estuarine water. Live P. marinus meronts significantly suppressed ROI production by zymosan-stimulated hemocytes. The suppression of ROI production was dose dependent. Suppression of ROI production from zymosan-stimulated hemocytes by heat killed P. marinus was significantly less than by live P. marinus. Similarly, CL of hemocytes was reduced, though not significantly when hemocytes were exposed to YRW preincubated with P. marinus. When P. marinus meronts were used as a stimulant, no CL response was elicited. Results of this study suggest that P. marinus cells are able to suppress ROI release from oyster hemocytes, thus evading this component of the host's defense. PMID:7556800

  6. Temperature-Dependent Persistence of Human Norovirus Within Oysters (Crassostrea virginica).

    PubMed

    Choi, Changsun; Kingsley, David H

    2016-06-01

    This study characterizes the persistence of human norovirus in Eastern oysters (Crassostrea virginica) held at different seawater temperatures. Oysters were contaminated with human norovirus GI.1 (Norwalk strain 8FIIa) by exposing them to virus-contaminated water at 15 °C, and subsequently holding them at 7, 15, and 25 °C for up to 6 weeks. Viral RNA was extracted from oyster tissue and hemocytes and quantitated by RT-qPCR. Norovirus was detected in hemocytes and oysters held at 7 and 15 °C for 6 weeks and in hemocytes and oysters held at 25 °C for up to 2 and 4 weeks, respectively. Results confirm that NoV is quite persistent within oysters and demonstrate that cooler water temperatures extend norovirus clearance times. This study suggests a need for substantial relay times to remove norovirus from contaminated shellfish and suggests that regulatory authorities should consider the effects of water temperature after a suspected episodic norovirus-contamination event. PMID:26983441

  7. Extraction and Identification of the Pigment in the Adductor Muscle Scar of Pacific Oyster Crassostrea gigas

    PubMed Central

    Wei, Lei; Li, Jian; Li, Zhonghu; Wang, Xiaotong

    2015-01-01

    In this study, UV (ultraviolet) and IR (infrared radiation) spectral analysis were integrated to identify the pigment in the adductor muscle scar of the Pacific oyster Crassostrea gigas. The pigment was extracted from the adductor muscle scars of cleaned oyster shells that were pulverized, hydrolyzed in hot hydrochloric acid, purified with diethyl ether, and dissolved in 0.01 mL/L NaOH. The maximum absorption of the pigment in the UV absorption spectrum within the range of 190–500 nm was observed between 210–220 nm. The UV absorbance decreased with increasing wavelength which was consistent with the UV spectral absorption characteristics of melanin. In addition, Fourier transform infrared spectroscopy scanning revealed characteristic absorption peaks that emerged near 3440 cm-1 and 1630 cm-1, which was consistent with infrared scanning features of eumelanin (a type of melanin). This study has demonstrated for the first time that the pigment in the adductor muscle scar of the Pacific oyster is melanin, hinting that the adductor muscle could be another organ pigmenting the mollusc shell with melanin other than mantle. PMID:26555720

  8. Reproductive responses and detoxification of estuarine oyster Crassostrea hongkongensis under metal stress: a seasonal study.

    PubMed

    Weng, Nanyan; Wang, Wen-Xiong

    2015-03-01

    Understanding the impacts of metal stress on the reproduction of dominant species, such as oysters, in seriously contaminated estuarine environments has great ecological implications. In the present study, the reproductive conditions were examined monthly for 1 year in oysters Crassostrea hongkongensis from a heavily metal-contaminated site (Baijiao, mainly by Cu and Zn) in the Jiulong River estuary and a relatively clean nearby estuary (Jiuzhen). Oysters sampled in the contaminated site showed a delayed gametogenesis, a relatively shorter spawning period, and a lower gonad condition index in comparison to the oysters sampled in the reference site. In particular, we found that the proportion of females increased significantly in the contaminated oysters, which provided the first evidence that the feminization in wild oyster populations could be related to trace metal pollution. Additionally, the potential detoxification mechanism of trace metals in oysters was also investigated. Compartmentalization of trace metals in membrane-limited vesicles in hemocytes could be an important detoxification mechanism for the contaminated oysters. Our findings indicated that the long-term metal exposure may greatly influence the reproduction of the oysters and finally affect the recruitment and population of this species. PMID:25660751

  9. Effects of High Hydrostatic Pressure on the Physical, Microbial, and Chemical Attributes of Oysters (Crassostrea virginica).

    PubMed

    Lingham, Talaysha; Ye, Mu; Chen, Haiqiang; Chintapenta, Lathadevi Karuna; Handy, Eunice; Zhao, Jing; Wu, Changqing; Ozbay, Gulnihal

    2016-05-01

    The change in the quality attributes (physical, microbial, and chemical) of oysters (Crassostrea virginica) after high hydrostatic pressure (HHP) treatment at 300 MPa at room temperature (RT, 25 °C) 300, 450, and 500 MPa at 0 °C for 2 min and control oysters without treatment were evaluated over 3 wk. The texture and tissue yield percentages of oysters HHP treated at 300 MPa, RT increased significantly (P < 0.05) compared to control. Aerobic and psychrotrophic bacteria in control oysters reached the spoilage point of 7 log CFU/g after 15 d. Coliform counts (log MPN/g) were low during storage with total and fecal coliforms less than 3.5 and 1.0. High pressure treated oysters at 500 MPa at 0 °C were significantly higher (P < 0.05) than oysters HHP treated at 300 MPa at 0 °C in lipid oxidation values. The highest pressure (500 MPa) treatment in this study, significantly (P < 0.05) decreased unsaturated fatty acid percentage compared to control. The glycogen content of control oysters at 3 wk was significantly higher (P < 0.05) when compared to HHP treated oysters [300 MPa, (RT); 450 MPa (0 °C); and 500 MPa (0 °C)]. HHP treatments of oysters were not significantly different in pH, percent salt extractable protein (SEP), and total lipid values compared to control. Based on our results, HHP prolongs the physical, microbial, and chemical quality of oysters. PMID:27074447

  10. Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

    PubMed Central

    Son, N T; Fleet, G H

    1980-01-01

    Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cells per g with either B. cereus, C. perfringens, V. parahaemolyticus, Salmonella typhimurium, or S. senftenberg. These species were cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light for sterilizing the depuration water. Escherichia coli was also cleansed from oysters under the same re-laying or depuration conditions so that its measurement alone could be used to indicate the cleansing of the above pathogenic species. The levels of these bacteria were also measured during the storage of oysters under conditions that occur during marketing. While B. cereus counts remained relatively stable during storage, the Salmonella spp. gradually decreased in numbers and C. perfringens rapidly died off. V. parahaemolyticus counts increased slightly during the first 4 days of storage, after which decreases occurred. PMID:6257164

  11. Identification and function of an evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) from Crassostrea hongkongensis.

    PubMed

    Qu, Fufa; Xiang, Zhiming; Wang, Fuxuan; Zhang, Yang; Li, Jun; Zhang, Yuehuan; Xiao, Shu; Yu, Ziniu

    2015-11-01

    Evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) is a multifunctional adaptor protein that plays a key role in the regulation of the oxidative phosphorylation (OXPHOS) system, bone morphogenetic protein (BMP) pathway and Toll-like receptor (TLR) signaling pathway in mammals. However, the function of ECSIT homologs in mollusks, the second most diverse group of animals, is not well understood. In this study, we identified an ECSIT homolog in the Hong Kong oyster Crassostrea hongkongensis (ChECSIT) and investigated its biological functions. The full-length cDNA of ChECSIT is 1734 bp and includes an open reading frame (ORF) of 1074 bp that encodes a polypeptide of 451 amino acids. The predicted ChECSIT protein shares similar structural characteristics with other known ECSIT family proteins. Quantitative real-time PCR analysis revealed that ChECSIT mRNA is broadly expressed in all of the examined tissues and at different stages of embryonic development; its transcript level could be significantly up-regulated by challenge with microorganisms (Vibrio alginolyticus, Staphylococcus haemolyticus and Saccharomyces cerevisiae). In addition, ChECSIT was found to be located primarily in the cytoplasm, and its overexpression stimulated the transcriptional activity of an NF-κB reporter gene in HEK293T cells. These findings suggest that ChECSIT might be involved in embryogenesis processes and immune responses in C. hongkongensis. PMID:26204814

  12. Preferential bivalent formation in tetraploid male of pacific oyster Crassostrea gigas Thunberg

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengrui; Wang, Xinglian; Zhang, Quanqi; Allen, Standish

    2013-11-01

    Artificially induced tetraploid Pacific oyster, Crassostrea gigas Thunberg, produces more aneuploid gametes than normal diploid one, although they showed a comparable fecundity to diploidy. The meiotic chromosome configuration of 3 tetraploid and 1 tetraploid/triploid mosaic males were analyzed through direct chromosome observation. A majority of metaphase I spermatocytes contained both bivalents and quadrivalents. The chromosome configuration of these males was characterized by preferential formation of bivalents to quadrivalents. Bivalents appeared in all spermatocytes and consisted of 86% of all chromosome aggregates. In comparison, quadrivalents occurred in 91% spermatocytes and consisted of only 12.6% of all chromosome aggregates. The mean bivalent frequency per spermatocyte varied between 14.4 and 17.2; while that of quadrivalents varied between 2.2 and 2.7. Most quadrivalents were tandemly chained (58%) or circled (39%). The total number of chromosome aggregates per spermatocyte ranged from 13 to 20 with an average of 17.6; while 18 (16 bivalents and 2 quadrivalents) was the most frequent. Univalents and trivalents appeared in very low frequency. Aneuploid (hypotetraploid) spermatocytes were observed in a low frequency. The chromosome configuration of in the mosaic individual was similar to that of tetraploid individuals. The percentage of triploid spermatocytes (2%) of the mosaic individual was significantly lower (χ2 =30, P < 0.01) than that of triploid cells (46%) in its somatic tissue.

  13. Toxicity of untreated wood leachates towards two saltwater organisms (Crassostrea gigas and Artemia franciscana).

    PubMed

    Libralato, G; Losso, C; Ghirardini, A Volpi

    2007-06-01

    Wood is widely used in the development of freshwater, estuarine and marine coastlines. Timbers last according to their content of naturally occurring preservatives (mostly phenols and aldehydes), produced to prevent decay from biotic agents. When untreated woods are exposed to aquatic media, leachates are generated with likely toxic effects on the target environment. The potential impact on saltwaters of leachates from some untreated timbers of both native and tropical species has been assessed. The leaching procedure was set up considering British Standard test methods for paints and OECD guidelines for wood preservatives emission scenarios. Toxicity was monitored via the acute toxicity test with the brine shrimp Artemia franciscana and the sub-chronic embryotoxicity test with the oyster Crassostrea gigas. Brine shrimps evidenced no toxic effects while oysters discriminated well among leachates: the tropical wood species showed similar or relatively lower toxic effects than the native ones according to both leaching cycles (24 and 72 h). The ecotoxicological data have been integrated with some physical and chemical parameters. PMID:17141956

  14. Ostreid herpesvirus type 1 replication and host response in adult Pacific oysters, Crassostrea gigas.

    PubMed

    Segarra, Amélie; Baillon, Laury; Tourbiez, Delphine; Benabdelmouna, Abdellah; Faury, Nicole; Bourgougnon, Nathalie; Renault, Tristan

    2014-01-01

    Since 2008, massive mortality outbreaks associated with OsHV-1 detection have been reported in Crassostrea gigas spat and juveniles in several countries. Nevertheless, adult oysters do not demonstrate mortality in the field related to OsHV-1 detection and were thus assumed to be more resistant to viral infection. Determining how virus and adult oyster interact is a major goal in understanding why mortality events are not reported among adult Pacific oysters. Dual transcriptomics of virus-host interactions were explored by real-time PCR in adult oysters after a virus injection. Thirty-nine viral genes and five host genes including MyD88, IFI44, IkB2, IAP and Gly were measured at 0.5, 10, 26, 72 and 144 hours post infection (hpi). No viral RNA among the 39 genes was detected at 144 hpi suggesting the adult oysters are able to inhibit viral replication. Moreover, the IAP gene (oyster gene) shows significant up-regulation in infected adults compared to control adults. This result suggests that over-expression of IAP could be a reaction to OsHV-1 infection, which may induce the apoptotic process. Apoptosis could be a main mechanism involved in disease resistance in adults. Antiviral activity of haemolymph against herpes simplex virus (HSV-1) was not significantly different between infected adults versus control. PMID:25294338

  15. Autotetraploid Pacific oysters (Crassostrea gigas) obtained using normal diploid eggs: induction and impact on cytogenetic stability.

    PubMed

    Benabdelmouna, Abdellah; Ledu, Christophe

    2015-07-01

    We describe two methods of producing viable and fertile autotetraploid Pacific oyster (Crassostrea gigas Thunberg) based on the use of normal-sized oocytes produced by normal diploid females. Our methods showed that the oocyte size is not a limiting factor for the success of the induction to autotetraploidy. These methods offer means of direct introgression of genetic progress from elite diploid lines to tetraploids used as broodstock, avoiding a triploid step with the risk of transferring undesirable traits from highly fecund triploids. High variability in the level of cytogenetic stability was found among the different tetraploid oysters tested, showing that induction method has an important impact on the long-term cytogenetic stability of the tetraploids. It appears that induction method based on the use of triploid females induces a greater cytogenetic instability among tetraploids so obtained, and this compared to tetraploids originating from the two methods described in our present study. As the aneuploidies and reversions observed in tetraploids can have serious consequences for the sustainability of tetraploid broodstock itself, as well as their triploid offspring, the two tetraploid induction methods described in the present work offer means to produce tetraploids with optimal cytogenetic, genetic, and zootechnical performances. PMID:26230146

  16. Functional analysis of Pacific oyster (Crassostrea gigas) β-thymosin: Focus on antimicrobial activity.

    PubMed

    Nam, Bo-Hye; Seo, Jung-Kil; Lee, Min Jeong; Kim, Young-Ok; Kim, Dong-Gyun; An, Cheul Min; Park, Nam Gyu

    2015-07-01

    An antimicrobial peptide, ∼5 kDa in size, was isolated and purified in its active form from the mantle of the Pacific oyster Crassostrea gigas by C18 reversed-phase high-performance liquid chromatography. Matrix-assisted laser desorption ionisation time-of-flight analysis revealed 4656.4 Da of the purified and unreduced peptide. A comparison of the N-terminal amino acid sequence of oyster antimicrobial peptide with deduced amino acid sequences in our local expressed sequence tag (EST) database of C. gigas (unpublished data) revealed that the oyster antimicrobial peptide sequence entirely matched the deduced amino acid sequence of an EST clone (HM-8_A04), which was highly homologous with the β-thymosin of other species. The cDNA possessed a 126-bp open reading frame that encoded a protein of 41 amino acids. To confirm the antimicrobial activity of C. gigas β-thymosin, we overexpressed a recombinant β-thymosin (rcgTβ) using a pET22 expression plasmid in an Escherichia coli system. The antimicrobial activity of rcgTβ was evaluated and demonstrated using a bacterial growth inhibition test in both liquid and solid cultures. PMID:25842181

  17. Growth and Survival of the American Oyster Crassostrea virginica in Jamaica Bay, New York

    PubMed Central

    Sarinsky, Gary; Carroll, Margaret A.; Nduka, Ebere; Catapane, Edward J.

    2016-01-01

    Jamaica Bay is a major inlet opening to the Atlantic Ocean. It was abundant with oysters until early 1900's. Over-harvesting, pressure from predators, parasitic invasion and declining water quality often are cited as causes. Despite actions to arrest and reverse the pollution, oysters are not reestablished. We are studying factors relating to the rehabitation of Crassostrea virginica in Jamaica Bay to determine if the water quality and environmental conditions are suitable for their survival. Oysters placed in Jamaica Bay grew well when housed in protective containers and growth was influenced by placement near the sediment as compared to the surface. Oysters placed 1 foot above the sediment grew larger that those suspended 1 foot below the surface. Water temperature, pH, turbidity, salinity, conductivity, chlorophyll-a and dissolved O2 were taken to compare water quality at each site. To study growth and survival in a more natural condition, oyster seed and adults were placed just off the bottom in unprotected containers and photographed. After 1 year they are growing and surviving well and there has been evidence of reproduction. Thus far there are no serious signs of predation by crabs or starfish. The study shows that Jamaica Bay water quality is suitable for oyster growth under the various conditions of our experiments. PMID:26862590

  18. Effect of cadmium on the defense response of Pacific oyster Crassostrea gigas to Listonella anguillarum challenge

    NASA Astrophysics Data System (ADS)

    Cong, Ming; Lü, Jiasen; Wu, Huifeng; Zhao, Jianmin

    2013-09-01

    Heavy metal pollution can affect the immune capability of organisms. We evaluated the effect of cadmium (Cd) on the defense responses of the Pacific oyster Crassostrea gigas to Listonella anguillarum challenge. The activities of several important defensive enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), acid phosphatase (ACP), Na+, K+ -ATPase in gills and hepatopancreas, and phenoloxidase-like (POL) enzyme in hemolymph were assayed. In addition, the expression levels of several genes, including heat shock protein 90 (HSP90), metallothionein (MT), and bactericidal/permeability increasing (BPI) protein were quantified by fluorescent quantitative PCR. The enzyme activities of SOD, ACP, POL, and GPx in hepatopancreas, and the expression of HSP90 were down-regulated, whereas GPx activity in the gill, Na+, K+-ATPase activities in both tissues, and MT expression was increased in Cdexposed oysters post L. anguillarum challenge. However, BPI expression was not significantly altered by co-stress of L. anguillarum infection and cadmium exposure. Our results suggest that cadmium exposure alters the oysters' immune responses and energy metabolism following vibrio infection.

  19. Effects of salinity on embryonic development, survival, and growth of Crassostrea hongkongensis

    NASA Astrophysics Data System (ADS)

    Huo, Zhongming; Wang, Zhaoping; Liang, Jian; Zhang, Yuehuan; Shen, Jianping; Yao, Tuo; Su, Jiaqi; Yu, Ruihai

    2014-08-01

    This study examined the effects of salinity on embryonic development, survival, and growth of the Hong Kong oyster Crassostrea hongkongensis. The embryos, larvae, and juveniles of C. hongkongensis were held in artificial seawater at three different salinities (low, 15; medium, 23; and high, 30) to determine the optimum hatchery and nursery conditions for mass production of the seeds. Results showed that the percentage production of straight-hinged larvae from fertilized eggs was significantly lower at the high salinity than at the low- and medium-salinities ( P < 0.05). The survival rates of larvae and juveniles differed significantly among the three salinity trials, with the highest survival rate observed at the low salinity ( P < 0.05). The shell height of larvae was significantly larger at the low salinity than at the high and medium salinities from days 9 to 15 ( P < 0.05), whereas that of juveniles was significantly larger at the low salinity than at the high and medium salinities on day 70 ( P < 0.05). These results indicate that the larvae and juveniles of C. hongkongensis are tolerant to a wide range of salinities (15 to 30), but show better growth and survival at relatively low salinities. Thus, it is recommended to use relatively low salinities in hatchery and nursery systems for improved yields of C. hongkongensis.

  20. Purification and characterization studies of cadmium-binding proteins from the American oyster, Crassostrea virginica

    SciTech Connect

    Fowler, B.A.; Engel, D.W.; Brouwer, M.

    1986-03-01

    The previously reported low molecular weight cadmium-binding protein (CdBP) from the American oyster, Crassostrea virginica, has been further purified and characterized by improved technical methods. The internal organ distribution of the protein within the oyster and effects of life cycle/season on CdBP production also have been evaluated. CdBP isolated by extended ion-exchange gradients or double ion-exchange chromatography followed by HPLC analysis possesses an electrophoretic R/sub f/ of about 0.7 and contains relatively little Zn. Cysteine, lysine, and glycine are the dominant amino acids. When ion-exchange columns are developed with NaCl gradients, the aromatic residues tryptophan, tyrosine, and phenylalanine are found to be present. The ultraviolet absorption spectrum of CdBP also was variable, with 250/280 nm ratios ranging from 17:1 immediately after ion-exchange chromatography to 2:1 following concentration procedures. Internal organ distribution studies showed that the visceral mass contained most of the Cd present with lesser amounts in the gills and mantle. Relative oyster dormancy during the winter also reduces CdBP production in response to Cd, and the protein is obtained most readily during the fall and spring.

  1. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions.

    PubMed

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-01-01

    The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met(5)]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met(5)]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors. PMID:27193598

  2. Evidence of a bactericidal permeability increasing protein in an invertebrate, the Crassostrea gigas Cg-BPI

    PubMed Central

    Gonzalez, Marcelo; Gueguen, Yannick; Destoumieux-Garzón, Delphine; Romestand, Bernard; Fievet, Julie; Pugnière, Martine; Roquet, Françoise; Escoubas, Jean-Michel; Vandenbulcke, Franck; Levy, Ofer; Sauné, Laure; Bulet, Philippe; Bachère, Evelyne

    2007-01-01

    A cDNA sequence with homologies to members of the LPS-binding protein and bactericidal/permeability-increasing protein (BPI) family was identified in the oyster Crassostrea gigas. The recombinant protein was found to bind LPS, to display bactericidal activity against Escherichia coli, and to increase the permeability of the bacterial cytoplasmic membrane. This indicated that it is a BPI rather than an LPS-binding protein. By in situ hybridization, the expression of the C. gigas BPI (Cg-bpi) was found to be induced in hemocytes after oyster bacterial challenge and to be constitutive in various epithelia of unchallenged oysters. Thus, Cg-bpi transcripts were detected in the epithelial cells of tissues/organs in contact with the external environment (mantle, gills, digestive tract, digestive gland diverticula, and gonad follicles). Therefore, Cg-BPI, whose expression profile and biological properties are reminiscent of mammalian BPIs, may provide a first line of defense against potential bacterial invasion. To our knowledge, this is the first characterization of a BPI in an invertebrate. PMID:17965238

  3. Early embryo and larval development of inviable intergeneric hybrids derived from Crassostrea angulata and Saccostrea cucullata

    NASA Astrophysics Data System (ADS)

    Su, Jiaqi; Wang, Zhaoping; Zhang, Yuehuan; Yan, Xiwu; Li, Qiongzhen; Yu, Ruihai

    2016-06-01

    To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6-8 d after hatching, and those survived could not complete metamorphosis. C. angulata ♀× S. cucullata ♂ larvae had a growth rate similar to that of the maternal species, whereas S. cucullata ♀ × C. angulata ♂ larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata.

  4. The simple neuroendocrine-immune regulatory network in oyster Crassostrea gigas mediates complex functions

    PubMed Central

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Sun, Ying; Wang, Mengqiang; Wang, Hao; Hou, Zhanhui; Gao, Dahai; Gao, Qiang; Song, Linsheng

    2016-01-01

    The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of the host. In the present study, the bioinformatical analysis of the transcriptomic data from oyster Crassostrea gigas and further biological validation revealed that oyster TNF (CgTNF-1 CGI_10018786) could activate the transcription factors NF-κB and HSF (heat shock transcription factor) through MAPK signaling pathway, and then regulate apoptosis, redox reaction, neuro-regulation and protein folding in oyster haemocytes. The activated immune cells then released neurotransmitters including acetylcholine, norepinephrine and [Met5]-enkephalin to regulate the immune response by arising the expression of three TNF (CGI_10005109, CGI_10005110 and CGI_10006440) and translocating two NF-κB (Cgp65, CGI_10018142 and CgRel, CGI_10021567) between the cytoplasm and nuclei of haemocytes. Neurotransmitters exhibited the immunomodulation effects by influencing apoptosis and phagocytosis of oyster haemocytes. Acetylcholine and norepinephrine could down-regulate the immune response, while [Met5]-enkephalin up-regulate the immune response. These results suggested that the simple neuroendocrine-immune regulatory network in oyster might be activated by oyster TNF and then regulate the immune response by virtue of neurotransmitters, cytokines and transcription factors. PMID:27193598

  5. Thermal stress induces a distinct transcriptome profile in the Pacific oyster Crassostrea gigas.

    PubMed

    Lim, Hyun-Jeong; Kim, Bo-Mi; Hwang, In Joon; Lee, Jeong-Soo; Choi, Ik-Young; Kim, Youn-Jung; Rhee, Jae-Sung

    2016-09-01

    Oysters are frequently subjected to heat stress during tidal emersion/immersion cycles in their habitats due to attachment on the rocky shore. To understand the effect of temperature elevation on the whole transcriptome over time, the Pacific oyster Crassostrea gigas was exposed to seawater temperature 32°C for 72h from the control 20°C. RNA-seq identified differentially expressed stress responsive transcripts upon thermal stress in the gill tissues of C. gigas. The primary effect of heat stress appears to be significantly induced transcription of molecular chaperones, including members of the heat shock protein (hsp) families, while genes typically associated with protein metabolism, such as those involved in protein degradation (e.g. ATP-dependent proteolysis pathway) and biosynthesis (e.g. ribosomal protein genes), were repressed. In particular, several hsp70 isoforms and a small hsp20 maintained prolonged mRNA expressions for 72h. This study provides preliminary insights into the molecular response of C. gigas to heat stress and suggests a basis for future studies examining molecular adaptation or thermotolerance metabolism in the Pacific oyster. PMID:27341139

  6. Linkage disequilibrium in wild and cultured populations of Pacific oyster ( Crassostrea gigas)

    NASA Astrophysics Data System (ADS)

    Guo, Xiang; Li, Qi; Kong, Lingfeng; Yu, Hong

    2016-04-01

    Linkage disequilibrium (LD) can be applied for mapping the actual genes responsible for variation of economically important traits through association mapping. The feasibility and efficacy of association studies are strongly dependent on the extent of LD which determines the number and density of markers in the studied population, as well as the experimental design for an association analysis. In this study, we first characterized the extent of LD in a wild population and a cultured mass-selected line of Pacific oyster ( Crassostrea gigas). A total of 88 wild and 96 cultured individuals were selected to assess the level of genome-wide LD with 53 microsatellites, respectively. For syntenic marker pairs, no significant association was observed in the wild population; however, three significant associations occurred in the cultured population, and the significant LD extended up to 12.7 cM, indicating that strong artificial selection is a key force for substantial increase of genome-wide LD in cultured population. The difference of LD between wild and cultured populations showed that association studies in Pacific oyster can be achieved with reasonable marker densities at a relatively low cost by choosing an association mapping population. Furthermore, the frequent occurrence of LD between non-syntenic loci and rare alleles encourages the joint application of linkage analysis and LD mapping when mapping genes in oyster. The information on the linkage disequilibrium in the cultured population is useful for future association mapping in oyster.

  7. Passage of a coccidial parasite (Eimeria acervulina) through the Eastern oyster (Crassostrea virginica).

    PubMed

    Lee, Marilyn B; Lee, Eng-Hong

    2003-04-01

    Human illness resulting from the consumption of raw oysters is well documented for bacterial and viral pathogens but not for coccidial parasites. This study explores the passage of coccidial parasites through and the viability of these parasites in the Eastern oyster, Crassostrea virginica. Because both Cryptosporidium and Toxoplasma are human parasites and are not safe to handle, we chose to work with a close relative, Eimeria acervulina, as a surrogate. This parasite was analyzed in chickens. Oysters were found to concentrate coccidial oocysts within 6 h of exposure in a seawater tank. After 24 h, oysters still contained viable oocysts, but by 48 h, few oysters contained viable oocysts. No oysters were found to harbor oocysts 72 or 96 h after exposure to oocysts. After oysters had been exposed to oocysts for 24 h in one saltwater tank and then transferred to a clean saltwater tank for 48 h, their feces tested positive for viable oocysts. We conclude that coccidial parasites are not pathogenic to oysters, but move through oysters in just 1 day. Unless contaminated waters continuously carry oocysts, raw oysters are unlikely to pose a threat to human health through the carriage of coccidial parasites. PMID:12696696

  8. The effects of cadmium of the growth and metallothionein expression of the bivalve larvae, crassostrea virginica

    SciTech Connect

    Craig, K.D.; Burnett, K.; Ringwood, A.; MacDougal, K.; Kendall, L.

    1994-12-31

    Oyster larvae, Crassostrea virginica, were exposed to 20 ppb of cadmium (Cd) and fed (mixture of Isochrysis galbana & Chaetoceros gracilis, 40mL) in the laboratory for 10 days. On the 0, 4, 7 and 10 day the larvae samples were taken and frozen. Then they were homogenized, centrifuged, ultrafiltered through a membrane separation technique used to segregate substances according to the molecular weight and size. The cytosolic protein was first partially purified by gel permeation, then by PAGE (Polyacrylamide Gel Electrophoresis). The controls and metal exposed larvae were evaluated on total wet weight and the metallothioneins (MT) were identified from the preparations using silver staining techniques. No significant changes could be detected in the controls. However, there was a great number dead at the beginning of the experiment. Cd accumulation began at the time of exposure. This suggests that surface area may play a role in determining short-term accumulation rates. Cd effects on growth (wet weight) was slightly different, the exposed weighed less than or equal to the controls. In addition, the Cd uptake via food played an insignificant role compared to direct uptake from sea water. Between day 0 and 7 there was a number of mortalities for the controls and exposed. In addition, there was a major weight change with the exposed, they appeared to weigh less than the controls on day 7, whereas on day 4 they weighed more. So weight is a very sensitive indicator of toxic stress.

  9. Demography of the ecosystem engineer Crassostrea gigas, related to vertical reef accretion and reef persistence

    NASA Astrophysics Data System (ADS)

    Walles, Brenda; Mann, Roger; Ysebaert, Tom; Troost, Karin; Herman, Peter M. J.; Smaal, Aad C.

    2015-03-01

    Marine species characterized as structure building, autogenic ecosystem engineers are recognized worldwide as potential tools for coastal adaptation efforts in the face of sea level rise. Successful employment of ecosystem engineers in coastal protection largely depends on long-term persistence of their structure, which is in turn dependent on the population dynamics of the individual species. Oysters, such as the Pacific oyster (Crassostrea gigas), are recognized as ecosystem engineers with potential for use in coastal protection. Persistence of oyster reefs is strongly determined by recruitment and shell production (growth), processes facilitated by gregarious settlement on extant shell substrate. Although the Pacific oyster has been introduced world-wide, and has formed dense reefs in the receiving coastal waters, the population biology of live oysters and the quantitative mechanisms maintaining these reefs has rarely been studied, hence the aim of the present work. This study had two objectives: (1) to describe the demographics of extant C. gigas reefs, and (2) to estimate vertical reef accretion rates and carbonate production in these oyster reefs. Three long-living oyster reefs (>30 years old), which have not been exploited since their first occurrence, were examined in the Oosterschelde estuary in the Netherlands. A positive reef accretion rate (7.0-16.9 mm year-1 shell material) was observed, consistent with self-maintenance and persistent structure. We provide a framework to predict reef accretion and population persistence under varying recruitment, growth and mortality scenarios.

  10. Epizootiology and pathology of juvenile oyster disease in the Eastern oyster, Crassostrea virginica.

    PubMed

    Ford, S E; Borrero, F J

    2001-10-01

    Juvenile Oyster Disease (JOD) causes mortalities of small cultured oysters, Crassostrea virginica. The present study was an intensive epizootiological and pathological investigation of JOD in eight sequentially deployed cohorts at sites on Long Island, New York. JOD symptoms and mortalities began in all groups at about the same time. Lesions on the mantle were detected histologically about 1 week before the principal symptom, a conchiolin deposit on the inner shell, appeared. Mortality began about 1 week later and reached 60-90% in oysters <25 mm. Mantle lesions were highly correlated with subsequent conchiolin-deposit prevalence and with total mortality. Larger juveniles (25-40 mm) were affected by the disease and produced conchiolin deposits, but mortalities did not exceed 30%. Mortalities were consistently related to size, but not necessarily to age or length of "exposure" in the field. There was no indication that JOD was linked to a particular broodstock or hatchery. Wild spat deployed at experimental sites showed JOD symptoms before the hatchery-produced groups did and cohorts maintained inside a hatchery experienced essentially no JOD. Histological examination of cohorts experiencing high mortalities failed to reveal an obvious etiological agent, but showed a disease pattern similar to that described for other bivalve diseases with a bacterial etiology. Similarities and differences between this and other studies of JOD suggest that one or more bacterial species is responsible for JOD, but that a trigger, probably temperature, is also involved and may vary from site to site. PMID:11812117

  11. Epigenetic features in the oyster Crassostrea gigas suggestive of functionally relevant promoter DNA methylation in invertebrates.

    PubMed

    Rivière, Guillaume

    2014-01-01

    DNA methylation is evolutionarily conserved. Vertebrates exhibit high, widespread DNA methylation whereas invertebrate genomes are less methylated, predominantly within gene bodies. DNA methylation in invertebrates is associated with transcription level, alternative splicing, and genome evolution, but functional outcomes of DNA methylation remain poorly described in lophotrochozoans. Recent genome-wide approaches improve understanding in distant taxa such as molluscs, where the phylogenetic position, and life traits of Crassostrea gigas make this bivalve an ideal model to study the physiological and evolutionary implications of DNA methylation. We review the literature about DNA methylation in invertebrates and focus on DNA methylation features in the oyster. Indeed, though our MeDIP-seq results confirm predominant intragenic methylation, the profiles depend on the oyster's developmental and reproductive stage. We discuss the perspective that oyster DNA methylation could be biased toward the 5'-end of some genes, depending on physiological status, suggesting important functional outcomes of putative promoter methylation from cell differentiation during early development to sustained adaptation of the species to the environment. PMID:24778620

  12. Vibrio crosai sp. nov., isolated from a cultured oyster Crassostrea gigas.

    PubMed

    González-Castillo, Adrián; Balboa, Sabela; Romalde, Jesús L; Gomez-Gil, Bruno

    2014-09-01

    A motile, facultative anaerobic, marine bacterial isolate (CAIM 1437(T)) was obtained from a cultured oyster (Crassostrea gigas) in Sonora, México. The strain was studied by a phylogenetic analysis based on sequences of the 16S rRNA and five housekeeping genes, i.e. ftsZ, gapA, pyrH, recA, and topA. Comparison of the almost-complete 16S rRNA gene sequence with those of other type strains of the genus Vibrio showed a close relationship with the type strains of Vibrio orientalis and Vibrio rotiferianus, with similarity values ranging from 98.4 to 98.3 %, respectively. MLSA placed this strain within the Orientalis clade. The DNA-DNA hybridization value of strain CAIM 1437(T) with V. orientalis was 59 % and with V. rotiferianus 55 %. The DNA G+C content was determined to be 45.6 mol %. Phenotypic characteristics also showed differences with the species analysed. The results presented here support the description of a novel species, for which the name Vibrio crosai sp. nov. is proposed, with CAIM 1437(T) (= DSM 27145(T)) as the type strain. PMID:24973134

  13. Epigenetic features in the oyster Crassostrea gigas suggestive of functionally relevant promoter DNA methylation in invertebrates

    PubMed Central

    Rivière, Guillaume

    2014-01-01

    DNA methylation is evolutionarily conserved. Vertebrates exhibit high, widespread DNA methylation whereas invertebrate genomes are less methylated, predominantly within gene bodies. DNA methylation in invertebrates is associated with transcription level, alternative splicing, and genome evolution, but functional outcomes of DNA methylation remain poorly described in lophotrochozoans. Recent genome-wide approaches improve understanding in distant taxa such as molluscs, where the phylogenetic position, and life traits of Crassostrea gigas make this bivalve an ideal model to study the physiological and evolutionary implications of DNA methylation. We review the literature about DNA methylation in invertebrates and focus on DNA methylation features in the oyster. Indeed, though our MeDIP-seq results confirm predominant intragenic methylation, the profiles depend on the oyster's developmental and reproductive stage. We discuss the perspective that oyster DNA methylation could be biased toward the 5′-end of some genes, depending on physiological status, suggesting important functional outcomes of putative promoter methylation from cell differentiation during early development to sustained adaptation of the species to the environment. PMID:24778620

  14. Moderate establishment success of Pacific oyster, Crassostrea gigas, on a sheltered intertidal mussel bed

    NASA Astrophysics Data System (ADS)

    Holm, Mark Wejlemann; Davids, Jens Kristian; Dolmer, Per; Vismann, Bent; Hansen, Benni Winding

    2015-10-01

    The Pacific oyster (Crassostrea gigas Thunberg 1793) is introduced into marine ecosystems worldwide. In Denmark, C. gigas was introduced into the micro tidal Limfjord, around 1972 for aquaculture. This study describes the population structure of C. gigas at Agger Tange in 2007, 2009, 2010 and 2011. Here, C. gigas use beds of Blue mussels (Mytilus edulis L.) as primary habitat. The mean abundance (± 1 SD) of C. gigas was unchanged during our study (45 ± 2 indv. m- 2), while it increased for M. edulis from 2010 to 2011 (934 ± 610 to 1434 ± 750 indv. m- 2, respectively). In 2009, a newly settled cohort of C. gigas was present, but in the succeeding years no or negligible recruitment was recorded. However, age cohort analyses, based on individual shell size at different ages, suggest successful recruitment in three out of seven years. A comparison with the course of the bioinvasion in List Tidal Basin, suggests that the population at Agger Tange is not in the expansion phase of the bioinvasion, despite of frequent settlement, high shell growth rates and relatively high abundance. So far, C. gigas has had moderate establishment success. We conclude that C. gigas is still in the establishment phase, but that this is prolonged, presumably due to low food availability.

  15. Introduction, establishment and expansion of the Pacific oyster Crassostrea gigas in the Oosterschelde (SW Netherlands)

    NASA Astrophysics Data System (ADS)

    Smaal, A. C.; Kater, B. J.; Wijsman, J.

    2009-03-01

    The Pacific oyster Crassostrea gigas was first introduced as an exotic species by oyster farmers in 1964 in the Oosterschelde estuary (SW Netherlands). The initial phase is not well documented but first natural spatfall was recorded in 1975. Excessive spatfall occurred in 1976 and this is considered the start of the expansion phase of the wild oysters. Oyster beds in intertidal and subtidal areas of the Oosterschelde estuary have been growing since. The development in the intertidal area has been reconstructed by using aerial photography, validated by ground truth in 2000-2002. In the subtidal areas extensive oyster beds have been detected by using side scan sonar; on hard substrates along the dikes coverage with oysters up to 90% locally has been recorded by scuba diving surveys. Expansion has also occurred into adjacent water bodies including the Wadden Sea. By forming resistant reefs the oysters induce structural changes in the ecosystem. It is concluded that bed area is still expanding while decrease of the fraction live animals may indicate adjustment of the stock size to the local conditions.

  16. Effects of ocean acidification on immune responses of the Pacific oyster Crassostrea gigas.

    PubMed

    Wang, Qing; Cao, Ruiwen; Ning, Xuanxuan; You, Liping; Mu, Changkao; Wang, Chunlin; Wei, Lei; Cong, Ming; Wu, Huifeng; Zhao, Jianmin

    2016-02-01

    Ocean acidification (OA), caused by anthropogenic CO2emissions, has been proposed as one of the greatest threats in marine ecosystems. A growing body of evidence shows that ocean acidification can impact development, survival, growth and physiology of marine calcifiers. In this study, the immune responses of the Pacific oyster Crassostrea gigas were investigated after elevated pCO2 exposure for 28 days. The results demonstrated that OA caused an increase of apoptosis and reactive oxygen species (ROS) production in hemocytes. Moreover, elevated pCO2 had an inhibitory effect on some antioxidant enzyme activities and decreased the GSH level in digestive gland. However, the mRNA expression pattern of several immune related genes varied depending on the exposure time and tissues. After exposure to pCO2 at ∼2000 ppm for 28 days, the mRNA expressions of almost all tested genes were significantly suppressed in gills and stimulated in hemocytes. Above all, our study demonstrated that elevated pCO2 have a significant impact on the immune systems of the Pacific oyster, which may constitute as a potential threat to increased susceptibility of bivalves to diseases. PMID:26706224

  17. Metals concentrations in sediments and oyster Crassostrea gigas from La Pitahaya lagoon, Sinaloa, NW Mexico

    NASA Astrophysics Data System (ADS)

    Luna Varela, R.; Muñoz Sevilla, N.; Campos Villegas, L.; Rodriguez Espinosa, P.; Gongora Gomez, A.; MP, J.

    2013-05-01

    This present study was performed in a culture of Crassostrea gigas in La Pitahaya, Sinaloa, México. The main objective is to identify the enrichment pattern of trace elements (Cu, Cd, Cr, Ni, Pb, Zn, Hg, As, V) also was determine concentrations thereof in oyster. Four sampling sites were selected, two smaller channels which connect the lagoon directly , the region of culture and connection with the sea ; and each sampling consisted of 4 sample sediments and 50 oysters of commercial size per mounth . Concentrations of trace metals were determined using atomic absorption spectrophotometry (AAS). The higher concentration of elements in certain samples clearly suggests that they are directly fed by the smaller channels which connect the lagoon directly. These small channels often carry the contaminants which are absorbed and deposited in the sediments. The results were also compared with the Effect Range Low (ERL) and Effect Range Medium (ERM) of NOAA and it indicates that Ni is above the ERL values. Cadmium, lead, chrome and copper concentrations exceeded the limits permissible of bivalbe mollusks established by the sanitary regulations

  18. Survey for protozoan parasites in Eastern oysters (Crassostrea virginica) from the Gulf of Maine using PCR-based assays.

    PubMed

    Marquis, Nicholas D; Record, Nicholas R; Robledo, José A Fernández

    2015-10-01

    Protozoan pathogens represent a serious threat to oyster aquaculture, since they can lead to significant production loses. Moreover, oysters can concentrate human pathogens through filter feeding, thus putting at risk raw oyster consumers' health. Using PCR-based assays in oysters (Crassostrea virginica) from Maine, we expand the Northeast range in the USA for the protozoans Perkinsus marinus, Perkinsus chesapeaki, and Haplosporidium nelsoni, and report for the first time the detection of the human pathogens Toxoplasma gondii and Cryptosporidium parvum. Oysters hosting both P. marinus and P. chesapeaki were more than three times as likely to be infected by a non-Perkinsus than those free of Perkinsus infections. PMID:25889457

  19. Inheritance of 15 microsatellites in the Pacific oyster Crassostrea gigas: segregation and null allele identification for linkage analysis

    NASA Astrophysics Data System (ADS)

    Li, Li; Guo, Ximing; Zhang, Guofan

    2009-02-01

    Microsatellites were screened in a backcross family of the Pacific oyster, Crassostrea gigas. Fifteen microsatellite loci were distinguishable and polymorphic with 6 types of allele-combinations. Null alleles were detected in 46.7% of loci, accounting for 11.7% of the total alleles. Four loci did not segregate in Mendelian Ratios. Three linkage groups were identified among 7 of the 15 segregating loci. Fluorescence-based automated capillary electrophoresis (ABI 310 Genetic Analyzer) that used to detect the microsatellite loci, has been proved a fast, precise, and reliable method in microsatellite genotyping.

  20. Simultaneous accumulations of naphthalene, a PCB mixture, and benzo(a)pyrene, by the oyster, Crassostrea virginica

    SciTech Connect

    Fortner, A.R.; Sick, L.V.

    1985-02-01

    The objective of the present investigation was to assess accumulations or ogranic contaminants when the oyster Crassostrea virginica was simultaneously exposed to several contaminants. Polychlorinated biphenyls (PCBs), naphthalene, and benzo(a)pyrene were selected for study due to their toxicity and ubiquitous distribution in the marine environment. The objective included considering the possible significance of contaminant accumulations to humans by using a commercially important organism, and possible antagonistic-synergistic effects of multiple contaminants. The bioavailability of contaminants presented as dissolved versus particulate matter was also investigated.

  1. Species profile: Life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): American oyster. [Crassostrea virginica

    SciTech Connect

    Stanley, J.G.; Sellers, M.A.

    1986-07-01

    The American oyster, Crassostrea virginica, is an important commercial species. Spawning occurs repeatedly during warmer months with millions of eggs released. Embryos and larvae are carried by currents throughout the estuaries and oceanic bays where they occur. The surviving larvae cement themselves to a solid object, where they remain for the remainder of life. Unable to move, they must tolerate changes in the environment that range from -2 to 36/sup 0/C (air temperature), 2 to 40 ppt salinity, and clear or muddy water. The density and occurrence of adults is limited by predators, chiefly oyster drills, whelks, fish, and crabs.

  2. Biometric, microstructural, and high-resolution trace element studies in Crassostrea gigas of Cantabria (Bay of Biscay, Spain): Anthropogenic and seasonal influences

    NASA Astrophysics Data System (ADS)

    Higuera-Ruiz, R.; Elorza, J.

    2009-04-01

    Living Crassostrea gigas oysters of different ages and sizes were collected in three estuaries of Cantabria (Bay of Biscay, Spain): San Vicente de la Barquera Estuary, Santander Bay, and Marismas de Santoña Estuary. The main objective was to determine different shell responses to variable environmental parameters. A shell morphological study, based on three biometric indices, indicates that oysters of Santander Bay have two significant shell anomalies: abnormal thickening of the right valve and loss of vital cavity volume. These shell abnormalities are related with the presence in these waters of the chemical tributyltin. In the other two estuaries, the oysters show no detectable anomalies. Four shell microstructures have been distinguished: Regular Simple Prismatic, Regular Foliated, cone-Complex Cross Foliated, and Chalk. In Santander Bay oysters, the Chalk forms a "root-type" framework, whereas in the other two estuaries it forms a more compact microstructure. It is proposed that exposure to tributyltin has produced this modification. High-spatial-resolution geochemical transects have been carried out on the Regular Foliated microstructure in the umbo region in order to evaluate the distribution of Mg, Sr, and Na. The elements analysed exhibit clear cyclic variations in San Vicente de la Barquera Estuary and Marismas de Santoña Estuary oysters, related with seasonal periods, and characterised by broad maxima during months in which the waters are warmer and have higher salinity. These patterns are buffered in Santander Bay oysters. Our results demonstrate that biometric, microstructural, and high-resolution trace element studies in oyster shells can provide information about contaminants and seasonal variations in the estuarine environment.

  3. Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

    PubMed Central

    Bouquet, Anne Lise; Maurice, Julien-Thomas; Lupo, Coralie; Blachier, Philippe

    2014-01-01

    A number of bivalve species worldwide, including the Pacific oyster, Crassostrea gigas, have been affected by mass mortality events associated with herpesviruses, resulting in significant losses. A particular herpesvirus was purified from naturally infected larval Pacific oysters, and its genome was completely sequenced. This virus has been classified as Ostreid herpesvirus 1 (OsHV-1) within the family Malacoherpesviridae. Since 2008, mass mortality outbreaks among C. gigas in Europe have been related to the detection of a variant of OsHV-1 called μVar. Additional data are necessary to better describe mortality events in relation to environmental-parameter fluctuations and OsHV-1 detection. For this purpose, a single batch of Pacific oyster spat was deployed in 4 different locations in the Marennes-Oleron area (France): an oyster pond (“claire”), a shellfish nursery, and two locations in the field. Mortality rates were recorded based on regular observation, and samples were collected to search for and quantify OsHV-1 DNA by real-time PCR. Although similar massive mortality rates were reported at the 4 sites, mortality was detected earlier in the pond and in the nursery than at both field sites. This difference may be related to earlier increases in water temperature. Mass mortality was observed among oysters a few days after increases in the number of PCR-positive oysters and viral-DNA amounts were recorded. An initial increment in the number of PCR-positive oysters was reported at both field sites during the survey in the absence of significant mortality. During this period, the water temperature was below 16°C. PMID:24973071

  4. CgIL17-5, an ancient inflammatory cytokine in Crassostrea gigas exhibiting the heterogeneity functions compared with vertebrate interleukin17 molecules.

    PubMed

    Xin, Lusheng; Zhang, Huan; Zhang, Ran; Li, Hui; Wang, Weilin; Wang, Lingling; Wang, Hao; Qiu, Limei; Song, Linsheng

    2015-12-01

    Interleukin 17 (IL17) is a proinflammatory cytokine that plays an important role in immune response. Recently, five novel IL17 homologs have been identified by screening and analyzing the genome of pacific oyster Crassostrea gigas. In the present study, the functions of CgIL17-5 were investigated by examining the distribution of its mRNA and protein, ligands binding and modulation in immune response. The mRNA expression levels of CgIL17-5 in hemocytes of oysters post twice challenges of Vibrio splendidus were all significantly up-regulated (P < 0.01), while the secondary pathogen infection attenuated the expression level of CgIL17-5 mRNA compared with the primary challenge. CgIL17-5 was found to be located on oyster hemocyte membranes through fluorescence confocal assay. The luciferase reporter assays showed that CgIL17-5 could activate the transfactors NF-κB, CREB and ATF-1, and involve in their signal pathways in HEK293T cells. Meanwhile, CgIL17-5 could augment the IL6 synthesis in HuVEC cells, playing the similar roles as human IL17 in inflammatory response. Additionally, the recombinant CgIL17-5 (rCgIL17-5) could directly bind peptidoglycan (PGN), lipopolysaccharide (LPS), poly (I:C) and β-1,3-glucan, with the highest affinity to PGN, and significantly inhibit the growth of Micrococcus luteus and Escherichia coli. All the results collectively suggested that CgIL17-5, as an ancient inflammatory cytokine, could not only activate signal transduction for the release of other cytokines, but also mediate the clearance of extracellular bacteria in oysters. PMID:26257382

  5. A novel siglec (CgSiglec-1) from the Pacific oyster (Crassostrea gigas) with broad recognition spectrum and inhibitory activity to apoptosis, phagocytosis and cytokine release.

    PubMed

    Liu, Conghui; Jiang, Shuai; Wang, Mengqiang; Wang, Lingling; Chen, Hao; Xu, Jiachao; Lv, Zhao; Song, Linsheng

    2016-08-01

    Sialic acid binding immunoglobulin-type lectin (siglec) belongs to the immunoglobulin superfamily (IgSF), which acts as regulator involved in glycan recognition and signal transduction in the immune and nervous systems. In the present study, a siglec gene (designated CgSiglec-1) was characterized from the Pacific oyster, Crassostrea gigas. The cDNA of CgSiglec-1 was of 1251 bp encoding a predicted polypeptide of 416 amino acids. CgSiglec-1 was composed of two I-set immunoglobulin (Ig) domains, one transmembrane (TM) domain and two ITIM motifs, sharing a sequence similarity with vertebrate CD22 homologs. The mRNA expression of CgSiglec-1 could be detected in all the selected tissues, with the highest level in hemocytes and labial palps. The confocal analysis revealed that CgSiglec-1 mainly distributed on the cytoplasmic membrane of the oyster hemocytes. In addition, the mRNA transcripts of CgSiglec-1 in hemocytes increased significantly (4.29-fold to that of control group, p < 0.05) after Vibrio splendidus stimulation. The recombinant CgSiglec-1 protein (rCgSiglec-1) could bind to poly sialic acid (pSIAS), lipopolysaccharides (LPS) and peptidoglycan (PGN) in a dose-dependent manner. The blockade of CgSiglec-1 by specific polyclonal antibodies could enhance the LPS-induced cell apoptosis, phagocytosis towards V. splendidus and the release of cytokines, such as CgTNF-1, CgIFNLP and CgIL-17. The results collectively indicated that CgSiglec-1 could act as a bridge molecule between invader recognition and signal transduction cascade, and modulate the immune response by inhibiting various important processes of immunity in oyster. PMID:27032602

  6. Identification and characterisation of an ostreid herpesvirus-1 microvariant (OsHV-1 µ-var) in Crassostrea gigas (Pacific oysters) in Australia.

    PubMed

    Jenkins, Cheryl; Hick, Paul; Gabor, Melinda; Spiers, Zoe; Fell, Shayne A; Gu, Xingnian; Read, Andrew; Go, Jeffrey; Dove, Michael; O'Connor, Wayne; Kirkland, Peter D; Frances, Jane

    2013-07-22

    Between November 2010 and January 2011, triploid Crassostrea gigas (Pacific oysters) cultivated in the Georges River, New South Wales, experienced >95% mortality. Mortalities also occurred in wild diploid C. gigas in the Georges River and shortly thereafter in the adjacent Parramatta River estuary upstream from Sydney Harbour. Neighbouring Saccostrea glomerata (Sydney rock oysters) did not experience mortalities in either estuary. Surviving oysters were collected to investigate the cause of mortalities. Histologically all oysters displayed significant pathology, and molecular testing revealed a high prevalence of ostreid herpesvirus-1 (OsHV-1). Quantitative PCR indicated that many C. gigas were carrying a high viral load at the time of sampling, while the load in S. glomerata was significantly lower (p < 0.001). Subsequent in situ hybridisation experiments confirmed the presence of a herpesvirus in C. gigas but not S. glomerata tissues, suggesting that S. glomerata is not susceptible to infection with OsHV-1. Naïve sentinel triploid C. gigas placed in the Georges River estuary in January 2011 quickly became infected and experienced nearly 100% mortality within 2 wk of exposure, indicating the persistence of the virus in the environment. Phylogenetic analysis of sequences derived from the C2/C6 region of the virus revealed that the Australian strain of OsHV-1 belongs to the microvariant (µ-var) cluster, which has been associated with severe mortalities in C. gigas in other countries since 2008. Environmental data revealed that the Woolooware Bay outbreaks occurred during a time of considerable environmental disturbance, with increased water temperatures, heavy rainfall, a toxic phytoplankton bloom and the presence of a pathogenic Vibrio sp. all potentially contributing to oyster stress. This is the first confirmed report of OsHV-1 µ-var related C. gigas mortalities in Australia. PMID:23872855

  7. Seasonal changes in mRNA encoding for cell stress markers in the oyster Crassostrea gigas exposed to radioactive discharges in their natural environment.

    PubMed

    Farcy, Emilie; Voiseux, Claire; Lebel, Jean-Marc; Fievet, Bruno

    2007-03-15

    The North Cotentin area (Normandy, France) hosts several nuclear facilities among which the AREVA reprocessing plant of La Hague is responsible for controlled discharges of liquid radioactive wastes into the marine environment. The resulting increase in radioactivity is very small compared to natural radioactivity. However, concerns about environment protection prompted the scientific community to focus on the effects of the chronic exposure to low concentrations of radionuclides in non-human biota. This study contributes to the evaluation of the possible impact of radioactive discharges on the oyster Crassostrea gigas in the field. Real-time polymerase chain reaction was used to quantify the expression levels of genes involved in cell stress in the oyster. They included members of the heat shock protein family (Hsp70, Hsc72, Hsp90), superoxide dismutase (SOD) and metallothionein (MT). Times series measurements were built from periodic samplings in the natural environment in order to characterize the natural variability as well as possible seasonal fluctuations. The genes studied exhibited a general seasonal expression pattern with a peak value in winter. The data inversely correlated with seawater temperature and the nature of the relationship between gene expression and temperature is discussed. In parallel, oysters were collected in four locations on the French shores, exposed or not to radioactive liquid wastes from the nuclear facilities hosted in the North Cotentin. The comparison of data obtained in the reference location on the Atlantic coast (not exposed) and data from oysters of the English Channel (exposed) gave no evidence for any statistical difference. However, because of the complexity of the natural environment, we cannot rule out the possibility that other parameters may have masked the impact of radioactive discharges. This dense set of data is a basis for the use of the expression levels of those genes as biomarkers to address the question of the

  8. A novel junctional adhesion molecule A (CgJAM-A-L) from oyster (Crassostrea gigas) functions as pattern recognition receptor and opsonin.

    PubMed

    Liu, Conghui; Wang, Mengqiang; Jiang, Shuai; Wang, Lingling; Chen, Hao; Liu, Zhaoqun; Qiu, Limei; Song, Linsheng

    2016-02-01

    Junctional adhesion molecule (JAM), a subfamily of immunoglobulin superfamily (IgSF) with a couple of immunoglobulin domains, can act as regulator in homeostasis and inflammation of vertebrates. In the present study, a structural homolog of JAM-A (designated CgJAM-A-L) was screened out from oyster, Crassostrea gigas, through a search of JAM-A D1 domain (N-terminal Ig domain in JAM-A). The cDNA of CgJAM-A-L was of 1188 bp encoding a predicted polypeptide of 395 amino acids. The immunoreactive area of CgJAM-A-L mainly distributed over the plasma membrane of hemocytes. After Vibro splendidus or tumor necrosis factor (CgTNF-1) stimulation, the mRNA transcripts of CgJAM-A-L in hemocytes increased significantly by 4.46-fold and 9.00-fold (p < 0.01) of those in control group, respectively. The recombinant CgJAM-A-L protein (rCgJAM-A-L) could bind multiple PAMPs including lipopolysaccharides (LPS), peptidoglycan (PGN), lipoteichoic acid (LTA), mannose (MAN), β-glucan (GLU) and poly(I:C), and various microorganisms including Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Vibro anguillarum, V. splendidus, Pastoris pastoris and Yarrowia lipolytica. The phagocytic rates of oyster hemocytes towards Gram-negative bacteria V. anguillarum and yeast P. pastoris were significantly enhanced after the incubation of rCgJAM-A-L, and even increased more significantly after the pre-incubation of rCgJAM-A-L with microbes (p < 0.01). The results collectively indicated that CgJAM-A-L functioned as an important pattern recognition receptor (PRR) and opsonin in the immune defense against invading pathogen in oyster. Moreover, as the most primitive specie with homolog of JAMs, the information of CgJAM-A-L in oyster would provide useful clues for the evolutionary study of JAMs and immunoglobulins. PMID:26434620

  9. Modelling reveals endogenous osmotic adaptation of storage tissue water potential as an important driver determining different stem diameter variation patterns in the mangrove species Avicennia marina and Rhizophora stylosa

    PubMed Central

    Vandegehuchte, Maurits W.; Guyot, Adrien; Hubeau, Michiel; De Swaef, Tom; Lockington, David A.; Steppe, Kathy

    2014-01-01

    Background Stem diameter variations are mainly determined by the radial water transport between xylem and storage tissues. This radial transport results from the water potential difference between these tissues, which is influenced by both hydraulic and carbon related processes. Measurements have shown that when subjected to the same environmental conditions, the co-occurring mangrove species Avicennia marina and Rhizophora stylosa unexpectedly show a totally different pattern in daily stem diameter variation. Methods Using in situ measurements of stem diameter variation, stem water potential and sap flow, a mechanistic flow and storage model based on the cohesion–tension theory was applied to assess the differences in osmotic storage water potential between Avicennia marina and Rhizophora stylosa. Key results Both species, subjected to the same environmental conditions, showed a resembling daily pattern in simulated osmotic storage water potential. However, the osmotic storage water potential of R. stylosa started to decrease slightly after that of A. marina in the morning and increased again slightly later in the evening. This small shift in osmotic storage water potential likely underlaid the marked differences in daily stem diameter variation pattern between the two species. Conclusions The results show that in addition to environmental dynamics, endogenous changes in the osmotic storage water potential must be taken into account in order to accurately predict stem diameter variations, and hence growth. PMID:24534674

  10. INVESTIGATIONS INTO THE EFFECTS OF SEASON AND WATER QUALITY ON OYSTERS (CRASSOSTREA VIRGINICA) AND ASSOCIATED FISH ASSEMBLAGES IN THE CALOOSAHATCHEE RIVER ESTUARY, FLORIDA: IMPLICATIONS OF ALTERED FRESHWATER INFLOW

    EPA Science Inventory

    A suite of biological and ecological responses of a Valued Ecosystem Component species, Crassostrea virginica, was used to investigate ecosystem-wide health effects of watershed alterations in the Caloosahatchee River estuary, Florida. The influence of water quality and season on...

  11. Copper exposure affects hemocyte apoptosis and Perkinsus marinus infection in eastern oysters Crassostrea virginica (Gmelin).

    PubMed

    Foster, Brent; Grewal, Snimar; Graves, Ondrea; Hughes, Francis M; Sokolova, Inna M

    2011-08-01

    Dermo disease in the eastern oyster (Crassostrea virginica) is caused by an intracellular protistan parasite Perkinsus marinus. The progression and outcome of this disease is determined by a complex interplay between the host's immunity and parasite's escape mechanisms, both of which can be influenced by environmental pollutants including heavy metals such as copper (Cu). The goal of the present study was to determine the effects of Cu on the levels of apoptosis (which can serve as an important host defense mechanism) in oyster immune cells (hemocytes) in vitro and in vivo as well as on the establishment of P. marinus infections in vivo. Surprisingly, Cu exerted opposing effects on apoptosis levels of hemocytes in vitro and in vivo, stimulating apoptosis in isolated hemocytes but suppressing it during Cu exposure of whole oysters. The mechanisms of this effect are presently unknown and may be related to the different bioavailability of the metal in vitro and in vivo. As expected, Cu accumulated in oyster soft tissues during in vitro exposure. Unexpectedly, this metal also strongly accumulated in hemolymph plasma which is classically considered isoionic with the surrounding seawater, likely reflecting the presence of soluble Cu-binding proteins in oyster plasma. Cu reduced growth of P. marinus in vitro and greatly reduced infection levels of hemocytes in vivo, presumably by direct toxic effects on the parasite. As a possible parasitic counterbalance, Cu accumulation in the hemocytes was reduced by P. marinus infection, although this reduction was not sufficient to prevent the parasiticidal effects of the heavy metal in vivo. This effect of Cu may be useful as a potential therapeutic against Dermo disease in aquaculture conditions. Overall, this study provides important new insights into the potential role of environmental metals in host-parasite relationships and disease dynamics in C. virginica. PMID:21658453

  12. Transcriptomic Responses to Salinity Stress in the Pacific Oyster Crassostrea gigas

    PubMed Central

    Zhao, Xuelin; Yu, Hong; Kong, Lingfeng; Li, Qi

    2012-01-01

    Background Low salinity is one of the main factors limiting the distribution and survival of marine species. As a euryhaline species, the Pacific oyster Crassostrea gigas is considered to be tolerant to relative low salinity. The genes that regulate C. gigas responses to osmotic stress were monitored using the next-generation sequencing of whole transcriptome with samples taken from gills. By RNAseq technology, transcript catalogs of up- and down-regulated genes were generated from the oysters exposed to low and optimal salinity seawater. Methodology/Principal Findings Through Illumina sequencing, we reported 1665 up-regulated transcripts and 1815 down-regulated transcripts. A total of 45771 protein-coding contigs were identified from two groups based on sequence similarities with known proteins. As determined by GO annotation and KEGG pathway mapping, functional annotation of the genes recovered diverse biological functions and processes. The genes that changed expression significantly were highly represented in cellular process and regulation of biological process, intracellular and cell, binding and protein binding according to GO annotation. The results highlighted genes related to osmoregulation, signaling and interactions of osmotic stress response, anti-apoptotic reactions as well as immune response, cell adhesion and communication, cytoskeleton and cell cycle. Conclusions/Significance Through more than 1.5 million sequence reads and the expression data of the two libraries, the study provided some useful insights into signal transduction pathways in oysters and offered a number of candidate genes as potential markers of tolerance to hypoosmotic stress for oysters. In addition, the characterization of C. gigas transcriptome will not only provide a better understanding of the molecular mechanisms about the response to osmotic stress of the oysters, but also facilitate research into biological processes to find underlying physiological adaptations to

  13. Disruption of amylase genes by RNA interference affects reproduction in the Pacific oyster Crassostrea gigas.

    PubMed

    Huvet, Arnaud; Béguel, Jean-Philippe; Cavaleiro, Nathalia Pereira; Thomas, Yoann; Quillien, Virgile; Boudry, Pierre; Alunno-Bruscia, Marianne; Fabioux, Caroline

    2015-06-01

    Feeding strategies and digestive capacities can have important implications for variation in energetic pathways associated with ecological and economically important traits, such as growth or reproduction in bivalve species. Here, we investigated the role of amylase in the digestive processes of Crassostrea gigas, using in vivo RNA interference. This approach also allowed us to investigate the relationship between energy intake by feeding and gametogenesis in oysters. Double-stranded (ds)RNA designed to target the two α-amylase genes A and B was injected in vivo into the visceral mass of oysters at two doses. These treatments caused significant reductions in mean mRNA levels of the amylase genes: -50.7% and -59% mRNA A, and -71.9% and -70.6% mRNA B in 15 and 75 µg dsRNA-injected oysters, respectively, relative to controls. Interestingly, reproductive knock-down phenotypes were observed for both sexes at 48 days post-injection, with a significant reduction of the gonad area (-22.5% relative to controls) and germ cell under-proliferation revealed by histology. In response to the higher dose of dsRNA, we also observed reductions in amylase activity (-53%) and absorption efficiency (-5%). Based on these data, dynamic energy budget modeling showed that the limitation of energy intake by feeding that was induced by injection of amylase dsRNA was insufficient to affect gonadic development at the level observed in the present study. This finding suggests that other driving mechanisms, such as endogenous hormonal modulation, might significantly change energy allocation to reproduction, and increase the maintenance rate in oysters in response to dsRNA injection. PMID:25883379

  14. Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Yang, Hongshuai; Liu, Jiahui; Li, Yanhong; Liu, Zhigang

    2015-07-01

    A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18-34°C) and copper ion concentration (0.1-1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant ( P<0.01), the quadratic effects of temperature were significant ( P<0.05), the linear effects of copper ion concentration were not significant ( P>0.05), and the quadratic effects of copper ion concentration were significant ( P<0.05). Additionally, the synergistic effects of temperature and copper ion concentration were not significant ( P>0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

  15. The cytochemical and ultrastructural characteristics of phagocytes in the Pacific oyster Crassostrea gigas.

    PubMed

    Jiang, Shuai; Jia, Zhihao; Xin, Lusheng; Sun, Ying; Zhang, Ran; Wang, Weilin; Wang, Lingling; Song, Linsheng

    2016-08-01

    Phagocytes have been proved to play vital roles in the innate immune response. However, the cellular characteristics of phagocytes in invertebrates, especially in molluscs, remain largely unknown. In the present study, fluorescence activated cell sorting (FACS) was employed to sort the phagocytes from the non-phagocytic haemocytes of the Pacific oyster Crassostrea gigas. The cytochemical staining analysis revealed that phagocytes were positive staining for α-naphthyl acetate esterase and myeloperoxidase, while negative staining for toluidine blue and periodic acid-Schiff. The non-phagocytic haemocytes exhibited positive staining for periodic acid-Schiff, weak positive staining for toluidine blue, but negative staining for α-naphthyl acetate esterase and myeloperoxidase. In addition, phagocytes exhibited ultrastructural cellular features similar to those of macrophages, with large cell diameter, rough cell membrane and extended pseudopodia revealed by the scanning electron microscopy, while the non-phagocytic haemocytes exhibited small cell diameter, smooth cell surface and round spherical shape. Transmission electron microscopy further demonstrated that phagocytes were abundant of cytoplasmic bodies and mitochondria, while non-phagocytic haemocytes were characterized as the comparatively large cell nucleus with contorted and condensed heterochromatin adherent to the nuclear envelope. Moreover, compared with non-phagocytic haemocytes, phagocytes exhibited significantly higher levels of intracellular cytokines, including tumor necrosis factor, interferon-like protein and interleukin-17, and significantly higher abundance of lysosome and reactive oxygen species, which were of great importance to the activation of immune response and pathogen clearance. Taken together, these findings revealed the different cytochemical and ultrastructural features between phagocytes and non-phagocytic haemocytes in C. gigas, which would provide an important clue to investigate the

  16. Metal speciation and toxicity of Tamar Estuary water to larvae of the Pacific oyster, Crassostrea gigas.

    PubMed

    Money, Cathryn; Braungardt, Charlotte B; Jha, Awadhesh N; Worsfold, Paul J; Achterberg, Eric P

    2011-07-01

    As part of the PREDICT Tamar Workshop, the toxicity of estuarine waters in the Tamar Estuary (southwest England) was assessed by integration of metal speciation determination with bioassays. High temporal resolution metal speciation analysis was undertaken in situ by deployment of a Voltammetric In situ Profiling (VIP) system. The VIP detects Cd (cadmium), Pb (lead) and Cu (copper) species smaller than 4 nm in size and this fraction is termed 'dynamic' and considered biologically available. Cadmium was mainly present in the dynamic form and constituted between 56% and 100% of the total dissolved concentration, which was determined subsequently in the laboratory in filtered discrete samples. In contrast, the dynamic Pb and Cu fractions were less important, with a much larger proportion of these metals associated with organic ligands and/or colloids (45-90% Pb and 46-85% Cu), which probably reduced the toxicological impact of these elements in this system. Static toxicity tests, based on the response of Crassostrea gigas larva exposed to discrete water samples showed a high level of toxicity (up to 100% abnormal development) at two stations in the Tamar, particularly during periods of the tidal cycle when the influence of more pristine coastal water was at its lowest. Competitive ligand-exchange Cu titrations showed that natural organic ligands reduced the free cupric ion concentration to levels that were unlikely to have been the sole cause of the observed toxicity. Nonetheless, it is probable that the combined effect of the metals determined in this work contributed significantly to the bioassay response. PMID:21704365

  17. Abcb1 gene expression pattern and function of copper detoxification in Fujian oyster, Crassostrea angulata.

    PubMed

    Shi, Bo; Xiang, Xu; Ke, Yizhou; Zhou, Long; Ke, Caihuan

    2015-12-01

    Oysters are considered hyper-accumulators of Cu, but the molecular mechanism by which they maintain Cu cell homeostasis is still unclear. ATP-binding cassette protein subfamily B member 1 (ABCB1, P-glycoprotein) can transport a variety of substrates across the cell membrane in aquatic animals. In this study, to provide insight into the roles of ABCB1 in resistance against Cu in oysters, complete cDNA of abcb1 gene in Crassostrea angulata was cloned and analyzed. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. Abcb1 was mainly expressed in the apical epithelial cell of gills and epithelia of mantles. Abcb1 expression and Cu accumulation were also studied in control oysters and oysters exposed to Cu (30, 100, 300 μg/L Cu, 1-15 days). Cu accumulation in the gill and mantle were measured after abcb1 gene interference. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. The mRNA transcript of abcb1 showed hypersensitivity to Cu exposure. A concentration-dependent highest abcb1 mRNA level (up to 5.61-fold to the control) in the gill and mantle existed across all Cu exposure concentrations after 3 days of Cu exposure. The gill and mantle Cu concentration were significantly higher after the abcb1 mRNA interference. According to these results, it is here speculated that ABCB1 may underlie cell protection against Cu in C. angulata. PMID:26310361

  18. [Effects of calcification on respiratory quotient of cultured oyster Crassostrea gigas and its fouling animals].

    PubMed

    Ren, Li-Hu; Zhang, Ji-Hong; Fang, Jian-Guang; Yao, Yong-Feng; Zhang, Yi-Tao; Gao, Zhen-Kun; Zhang, Ming-Liang

    2014-06-01

    Respiratory quotient (RQ) is one of the basic indices in physiology and energy metabolism of animals. When RQ is calculated, the amount of released CO2 is typically used directly. But for calcifying marine organisms, calcification which can affect dissolved inorganic carbon (DIC) content in the water may cause methodological error to some extent, if it is ignored. In this paper, RQ and O/N of cultured oyster Crassostrea gigas and 3 marine fouling animal species (Mytilus edulis, Ciona intestinalis, Styela clava) were measured in the respiratory chamber to discuss the effect of calcification in RQ determination. The results demonstrated that calcification rates of C. gigas and M. edulis were (56.37 +/- 14.85) and (17.95 +/- 7.21) micromol x g(-1) x h(-1), respectively. (3.72 +/- 0.80) and (1.48 +/- 0.14) mg x L(-1) DIC in the water were correspondingly decreased, which occupied about (60.9 +/- 7.6)% and (39.9 +/- 5.7)% of respired CO2, respectively. RQ values of 4 animals were C. gigas 1.38 +0.19, M. edulis 1.18 +/- 0.11, C. intestinalis 1.11 +/- 0.05 and S. clava 1.32 +/- 0.19, which agreed with the O/N values except C. intestinalis. Meanwhile, the uncorrected RQ values of C. gigas and M. edulis were 0.56 +/- 0.19 and 0.70 +/- 0.04, respectively, which were contrary to the O/N values. Therefore, it was obviously that calcification could result in a significant influence on the respiratory quotient by affecting water DIC concentration and should be accurately calculated in RQ measurement. PMID:25223039

  19. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity.

    PubMed

    Trevisan, Rafael; Arl, Miriam; Sacchet, Cássia Lopes; Engel, Cristiano Severino; Danielli, Naissa Maria; Mello, Danielle Ferraz; Brocardo, Caroline; Maris, Angelica Francesca; Dafre, Alcir Luiz

    2012-02-01

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 μM for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH-CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  20. Discovery and validation of genic single nucleotide polymorphisms in the Pacific oyster Crassostrea gigas.

    PubMed

    Wang, Jiafeng; Qi, Haigang; Li, Li; Que, Huayong; Wang, Di; Zhang, Guofan

    2015-01-01

    The economic and ecological importance of the oyster necessitates further research on the molecular mechanisms, which both regulate the commercially important traits of the oyster and help it to survive in the variable marine environment. Single nucleotide polymorphisms (SNPs) have been widely used to assess genetic variation and identify genes underlying target traits. In addition, high-resolution melting (HRM) analysis is a potentially powerful method for validating candidate SNPs. In this study, we adopted a rapid and efficient pipeline for the screening and validation of SNPs in the genic region of Crassostrea gigas based on transcriptome sequencing and HRM analysis. Transcriptomes of three wild oyster populations were sequenced using Illumina sequencing technology. In total, 50-60 million short reads, corresponding to 4.5-5.4 Gbp, from each population were aligned to the oyster genome, and 5.8 × 10(5) SNPs were putatively identified, resulting in a predicted SNP every 47 nucleotides on average. The putative SNPs were unevenly distributed in the genome and high-density (≥2%), nonsynonymous coding SNPs were enriched in genes related to apoptosis and responses to biotic stimuli. Subsequently, 1,671 loci were detected by HRM analysis, accounting for 64.7% of the total selected candidate primers, and finally, 1,301 polymorphic SNP markers were developed based on HRM analysis. All of the validated SNPs were distributed into 897 genes and located in 672 scaffolds, and 275 of these genes were stress inducible under unfavourable salinity, temperature, and exposure to air and heavy metals. The validated SNPs in this study provide valuable molecular markers for genetic mapping and characterization of important traits in oysters. PMID:24823694

  1. Exploitable Lipids and Fatty Acids in the Invasive Oyster Crassostrea gigas on the French Atlantic Coast.

    PubMed

    Dagorn, Flore; Couzinet-Mossion, Aurélie; Kendel, Melha; Beninger, Peter G; Rabesaotra, Vony; Barnathan, Gilles; Wielgosz-Collin, Gaëtane

    2016-06-01

    Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg) on the French Atlantic coast. Total lipid and phospholipid (PL) fatty acids (FAs) and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances. The total lipid level (% dry weight) varied from 7.1% (winter) to 8.6% (spring). Of this, PLs accounted for 28.1% (spring) to 50.4% (winter). Phosphatidylcholine was the dominant PL throughout the year (up to 74% of total PLs in winter). Plasmalogens were identified throughout the year as a series of eleven dimethylacetals (DMAs) with chain lengths between C16 and C20 (up to 14.5% of PL FAs + DMAs in winter). Thirty-seven FAs were identified in the PL FAs. Eicosapentaenoic acid (20:5n-3 EPA/7.53% to 14.5%) and docosahexaenoic acid (22:6n-3 DHA/5.51% to 9.5%) were the dominant polyunsaturated FAs in all seasons. Two non-methylene-interrupted dienoic (NMID) FAs were identified in all seasons: 7,13-docosadienoic and 7,15-docosadienoic acids, the latter being present at relatively high levels (up to 9.6% in winter). Twenty free sterols were identified, including cholesterol at 29.9% of the sterol mixture and about 33% of phytosterols. C. gigas tissues thus contained exploitable lipids for health benefits or as a potential source of high-quality commercial lecithin. PMID:27231919

  2. Effect of Carbonate Chemistry Alteration on the Early Embryonic Development of the Pacific Oyster (Crassostrea gigas)

    PubMed Central

    Gazeau, Frédéric; Gattuso, Jean-Pierre; Greaves, Mervyn; Elderfield, Henry; Peene, Jan; Heip, Carlo H. R.; Middelburg, Jack J.

    2011-01-01

    Ocean acidification, due to anthropogenic CO2 absorption by the ocean, may have profound impacts on marine biota. Calcareous organisms are expected to be particularly sensitive due to the decreasing availability of carbonate ions driven by decreasing pH levels. Recently, some studies focused on the early life stages of mollusks that are supposedly more sensitive to environmental disturbances than adult stages. Although these studies have shown decreased growth rates and increased proportions of abnormal development under low pH conditions, they did not allow attribution to pH induced changes in physiology or changes due to a decrease in aragonite saturation state. This study aims to assess the impact of several carbonate-system perturbations on the growth of Pacific oyster (Crassostrea gigas) larvae during the first 3 days of development (until shelled D-veliger larvae). Seawater with five different chemistries was obtained by separately manipulating pH, total alkalinity and aragonite saturation state (calcium addition). Results showed that the developmental success and growth rates were not directly affected by changes in pH or aragonite saturation state but were highly correlated with the availability of carbonate ions. In contrast to previous studies, both developmental success into viable D-shaped larvae and growth rates were not significantly altered as long as carbonate ion concentrations were above aragonite saturation levels, but they strongly decreased below saturation levels. These results suggest that the mechanisms used by these organisms to regulate calcification rates are not efficient enough to compensate for the low availability of carbonate ions under corrosive conditions. PMID:21860666

  3. Differential gene transcription, biochemical responses, and cytotoxicity assessment in Pacific oyster Crassostrea gigas exposed to ibuprofen.

    PubMed

    Serrano, Miguel A S; Gonzalez-Rey, Maria; Mattos, Jacó J; Flores-Nunes, Fabrício; Mello, Álvaro C P; Zacchi, Flávia L; Piazza, Clei E; Siebert, Marília N; Piazza, Rômi S; Alvarez-Muñoz, Diana; Rodriguez-Mozaz, Sara; Barceló, Damià; Bebianno, Maria João; Gomes, Carlos H A M; Melo, Cláudio M R; Bainy, Afonso C D

    2015-11-01

    Pharmaceuticals, such as anti-inflammatory nonsteroidal drugs, are frequently detected in aquatic ecosystems. Studies about the effects of these substances in nontarget organisms, such as bivalves, are relevant. The aim of this study was to evaluate the effects on antioxidant status caused by ibuprofen (IBU) in oysters Crassostrea gigas exposed for 1, 4, and 7 days at concentrations 1 and 100 μg L(-1). Levels of IBU in tissues of oysters, as well as cell viability of hemocytes, were measured. The transcription of cytochrome P450 genes (CYP2AU2, CYP356A1, CYP3071A1, CYP30C1), glutathione S-transferase isoforms (GST-ω-like and GST-π-like), cyclooxygenase-like (COX-like), fatty acid binding protein-like (FABP-like), caspase-like, heat shock protein-like (HSP70-like), catalase-like (CAT-like), and the activity of catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) were also evaluated in the gills of oysters. The highest levels of IBU were observed in animals exposed to 100 μg L(-1). A significant upregulation of CYP2AU1, CYP356A1, CYP3071A1, GST-ω-like, GST-π-like, COX-like, and FABP-like was observed in oysters exposed to IBU under different experimental conditions. Oysters exposed to 1 μg L(-1) for 7 days showed a significantly higher transcription of CYP2AU2, CYP356A1, CYP3071A1, GST-ω-like, and GST-π-like but lower GR activity. In conclusion, C. gigas exposed to environmentally relevant concentrations of IBU (1 μg L(-1)) exhibited increased transcription of certain genes and alterations on antioxidant and auxiliary enzymes, which could, in the the long term, cause damages to exposed organisms. PMID:25595931

  4. Genome and Transcriptome Analyses Provide Insight into the Euryhaline Adaptation Mechanism of Crassostrea gigas

    PubMed Central

    Zhang, Linlin; Li, Chunyan; Li, Li; She, Zhicai; Huang, Baoyu; Zhang, Guofan

    2013-01-01

    Background The Pacific oyster, Crassostrea gigas, has developed special mechanisms to regulate its osmotic balance to adapt to fluctuations of salinities in coastal zones. To understand the oyster’s euryhaline adaptation, we analyzed salt stress effectors metabolism pathways under different salinities (salt 5, 10, 15, 20, 25, 30 and 40 for 7 days) using transcriptome data, physiology experiment and quantitative real-time PCR. Results Transcriptome data uncovered 189, 480, 207 and 80 marker genes for monitoring physiology status of oysters and the environment conditions. Three known salt stress effectors (involving ion channels, aquaporins and free amino acids) were examined. The analysis of ion channels and aquaporins indicated that 7 days long-term salt stress inhibited voltage-gated Na+/K+ channel and aquaporin but increased calcium-activated K+ channel and Ca2+ channel. As the most important category of osmotic stress effector, we analyzed the oyster FAAs metabolism pathways (including taurine, glycine, alanine, beta-alanine, proline and arginine) and explained FAAs functional mechanism for oyster low salinity adaptation. FAAs metabolism key enzyme genes displayed expression differentiation in low salinity adapted individuals comparing with control which further indicated that FAAs played important roles for oyster salinity adaptation. A global metabolic pathway analysis (iPath) of oyster expanded genes displayed a co-expansion of FAAs metabolism in C. gigas compared with seven other species, suggesting oyster’s powerful ability regarding FAAs metabolism, allowing it to adapt to fluctuating salinities, which may be one important mechanism underlying euryhaline adaption in oyster. Additionally, using transcriptome data analysis, we uncovered salt stress transduction networks in C. gigas. Conclusions Our results represented oyster salt stress effectors functional mechanisms under salt stress conditions and explained the expansion of FAAs metabolism pathways as

  5. Assessment of gamete quality for the eastern oyster (Crassostrea virginica) by use of fluorescent dyes

    USGS Publications Warehouse

    Paniagua-Chavez, C. G.; Jenkins, J.; Segovia, M.; Tiersch, T.R.

    2006-01-01

    Evaluation of sperm motility is the single most widely used parameter to determine semen quality in mammals and aquatic species. While a good indicator for fresh sperm viability, post-thaw motility is not always effective at predicting fertilizing ability. Techniques using fluorescent dyes can assess functionality of mammalian sperm, but have not been widely applied in aquatic organisms. The eastern oyster Crassostrea virginica is an important mollusk in the United States, and cryopreservation protocols have been developed to preserve sperm and larvae to assist research and hatchery production. In this study, protocols were developed to assess sperm cell membrane integrity and mitochondrial function by flow cytometry and to assess viability of eggs by fluorescence microscopy. The fluorescent dyes SYBR 14 and propidium iodide (PI) (to assess membrane integrity) and rhodamine 123 (R123) (to assess mitochondrial membrane potential) were used to evaluate the quality of thawed oyster sperm previously cryopreserved with different cryoprotectant and thawing treatments. Membrane integrity results were correlated with motility of thawed sperm and mitochondrial membrane potential with fertilizing ability. Fluorescein diacetate (FDA) was used to assess cytotoxicity of cryoprotectant solutions and post-thaw damage to oyster eggs. The results indicated that membrane integrity (P = 0.004) and thawing treatments (P = 0.04), and mitochondrial membrane potential (P = 0.0015) were correlated with motility. Fertilizing ability was correlated with cryoprotectant treatments (P = 0.0258) and with mitochondrial membrane potential (P = 0.001). The dye FDA was useful in indicating structural integrity of fresh and thawed eggs. Exposure of eggs, without freezing, to dimethyl sulfoxide yielded higher percentages of stained eggs and fertilization rate than did exposure to propylene glycol (P = 0.002). Thawed eggs were not stained with FDA (<1%) and larvae were not produced. ?? 2006 Elsevier

  6. Transcriptional changes in Crassostrea gigas oyster spat following a parental exposure to the herbicide diuron.

    PubMed

    Rondon, R; Akcha, F; Alonso, P; Menard, D; Rouxel, J; Montagnani, C; Mitta, G; Cosseau, C; Grunau, C

    2016-06-01

    The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key coastal economic resource in France. High mortalities affect Pacific oysters since 2008 in France and Europe. Their origins have been attributed to a combination of biotic and abiotic factors, underlining the importance of environment quality. The impact of water pollution has been pointed out and one of the pollutants, the genotoxic herbicide diuron, occurs at high concentrations all along the French coasts. Previous work has revealed that a parental exposure to diuron had a strong impact on hatching rates and offspring development even if spats were not exposed to diuron themselves. In this study, we explored for the first time the transcriptional changes occurring in oyster spats (non exposed) originating from genitors exposed to an environmentally relevant concentration of diuron during gametogenesis using the RNAseq methodology. We identified a transcriptomic remodeling revealing an effect of the herbicide. Different molecular pathways involved in energy production, translation and cell proliferation are particularly disturbed. This analysis revealed modulated candidate genes putatively involved in response to oxidative stress and mitochondrial damage in offspring of genitors exposed to diuron. Complementary measures of the activity of enzymes involved in these latter processes corroborate the results obtained at the transcriptomic level. In addition, our results suggested an increase in energy production and mitotic activity in 5-month-spats from diuron-exposed genitors. These results could correspond to a "catch-up growth" phenomenon allowing the spats from diuron-exposed genitors, which displayed a growth delay at 3 months, to gain a normal size when they reach the age of 6 months. These results indicate that exposure to a concentration of diuron that is frequently encountered in the field during the oyster's gametogenesis stage can impact the next generation

  7. Cadmium-dependent oxygen limitation affects temperature tolerance in eastern oysters (Crassostrea virginica Gmelin).

    PubMed

    Lannig, Gisela; Cherkasov, Anton S; Pörtner, Hans-O; Bock, Christian; Sokolova, Inna M

    2008-04-01

    Marine ectotherms, including oysters are exposed to variable environmental conditions in coastal shallow waters and estuaries. In the light of global climate change, additional stressors like pollution might pose higher risk to populations. On the basis of the concept of oxygen- and capacity-limited thermal tolerance in aquatic ectotherms (40), we show that a persistent pollutant, cadmium, can have detrimental effects on oysters (Crassostrea virginica). During acute warming from 20 to 28 degrees C (4 degrees C/48 h) standard metabolic rate (SMR) rose in control and cadmium-exposed (50 microg Cd2+/l) animals, with a consistently higher SMR in Cd-exposed oysters. Additionally, Cd-exposed oysters showed a stronger temperature-dependent decrease in hemolymph oxygen partial pressures. This observation indicates that the effect of temperature on aerobic metabolism was exacerbated due to the additional Cd stress. The oxygen delivery systems could not provide enough oxygen to cover Cd-induced elevated metabolic demands at high temperatures. Interestingly, cardiac performance (measured as the heart rate and hemolymph supply to tissues) rose to a similar extent in control and Cd-exposed oysters with warming indicating that cardiac output was unable to compensate for elevated energy demand in Cd-exposed oysters. Together with the literature data on metal-induced reduction of ventilatory capacity, these findings suggest that synergistic effects of elevated temperatures and cadmium exposure led to oxygen limitation by impaired performance in oxygen supply through ventilation and circulation. Overall, cadmium exposure resulted in progressive hypoxemia in oysters at high temperatures, suggesting that the thermal tolerance window is narrowed in marine ectotherms inhabiting polluted areas compared with pristine environments. PMID:18272660

  8. Identification and functional characterization of two executioner caspases in Crassostrea gigas.

    PubMed

    Qu, Tao; Huang, Baoyu; Zhang, Linlin; Li, Li; Xu, Fei; Huang, Wen; Li, Chunyan; Du, Yishuai; Zhang, Guofan

    2014-01-01

    Caspase-3 and caspase-7 are two key effector caspases that play important roles in apoptotic pathways that maintain normal tissue and organ development and homeostasis. However, little is known about the sequence, structure, activity, and function of effector caspases upon apoptosis in mollusks, especially marine bivalves. In this study, we investigated the possible roles of two executioner caspases in the regulation of apoptosis in the Pacific oyster Crassostrea gigas. A full-length caspase-3-like gene named Cgcaspase-3 was cloned from C.gigas cDNA, encoding a predicted protein containing caspase family p20 and p10 domain profiles and a conserved caspase active site motif. Phylogenetic analysis demonstrated that both Cgcaspase-3 and Cgcaspase-1 may function as effector caspases clustered in the invertebrate branch. Although the sequence identities between the two caspases was low, both enzymes possessed executioner caspase activity and were capable of inducing cell death. These results suggested that Cgcaspase-3 and Cgcaspase-1 were two effector caspases in C. gigas. We also observed that nucleus-localized Cgcaspase-3, may function as a caspase-3-like protein and cytoplasm-localized Cgcaspase-1 may function as a caspase-7-like protein. Both Cgcaspase-3 and Cgcaspase-1 mRNA expression increased after larvae settled on the substratum, suggesting that both caspases acted in several tissues or organs that degenerated after oyster larvae settlement. The highest caspase expression levels were observed in the gills indicating that both effector caspases were likely involved in immune or metabolic processes in C. gigas. PMID:24551213

  9. Linkage Maps of Microsatellite DNA Markers for the Pacific Oyster Crassostrea gigas

    PubMed Central

    Hubert, Sophie; Hedgecock, Dennis

    2004-01-01

    We constructed male and female consensus linkage maps for the Pacific oyster Crassostrea gigas, using a total of 102 microsatellite DNA markers typed in 11-day-old larvae from three families. We identified 11 and 12 linkage groups in the male and female consensus maps, respectively. Alignment of these separate maps, however, suggests 10 linkage groups, which agrees with the haploid chromosome number. The male linkage map comprises 88 loci and spans 616.1 cM, while the female map comprises 86 loci and spans 770.5 cM. The male and the female maps share 74 loci; 2 markers remain unlinked. The estimated coverages for the consensus linkage maps are 79% for the male and 70–75% for the female, on the basis of two estimates of genome length. Ninety-five percent of the genome is expected to lie within 16 and 21 cM of markers on the male and female maps, respectively, while 95% of simulated minimum distances to the male and female maps are within 10.1 and 13.6 cM, respectively. Females have significantly more recombination than males, across 118 pairs of linked markers in common to the parents of the three families. Significant differences in recombination and orders of markers are also evident among same-sex parents of different families as well as sibling parents of opposite sex. These observations suggest that polymorphism for chromosomal rearrangements may exist in natural populations, which could have profound implications for interpreting the evolutionary genetics of the oyster. These are the first linkage maps for a bivalve mollusc that use microsatellite DNA markers, which should enable them to be transferred to other families and to be useful for further genetic analyses such as QTL mapping. PMID:15454548

  10. Exploitable Lipids and Fatty Acids in the Invasive Oyster Crassostrea gigas on the French Atlantic Coast

    PubMed Central

    Dagorn, Flore; Couzinet-Mossion, Aurélie; Kendel, Melha; Beninger, Peter G.; Rabesaotra, Vony; Barnathan, Gilles; Wielgosz-Collin, Gaëtane

    2016-01-01

    Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg) on the French Atlantic coast. Total lipid and phospholipid (PL) fatty acids (FAs) and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances. The total lipid level (% dry weight) varied from 7.1% (winter) to 8.6% (spring). Of this, PLs accounted for 28.1% (spring) to 50.4% (winter). Phosphatidylcholine was the dominant PL throughout the year (up to 74% of total PLs in winter). Plasmalogens were identified throughout the year as a series of eleven dimethylacetals (DMAs) with chain lengths between C16 and C20 (up to 14.5% of PL FAs + DMAs in winter). Thirty-seven FAs were identified in the PL FAs. Eicosapentaenoic acid (20:5n-3 EPA/7.53% to 14.5%) and docosahexaenoic acid (22:6n-3 DHA/5.51% to 9.5%) were the dominant polyunsaturated FAs in all seasons. Two non-methylene-interrupted dienoic (NMID) FAs were identified in all seasons: 7,13-docosadienoic and 7,15-docosadienoic acids, the latter being present at relatively high levels (up to 9.6% in winter). Twenty free sterols were identified, including cholesterol at 29.9% of the sterol mixture and about 33% of phytosterols. C. gigas tissues thus contained exploitable lipids for health benefits or as a potential source of high-quality commercial lecithin. PMID:27231919