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Sample records for crassostrea rhizophorae collected

  1. Detection of Toxoplasma gondii DNA in Brazilian oysters (Crassostrea rhizophorae).

    PubMed

    Ribeiro, L A; Santos, L K N S S; Brito, P A; Maciel, B M; Da Silva, A V; Albuquerque, G R

    2015-05-04

    The aim of this study was to detect evidence of Toxoplasma gondii using polymerase chain reaction (PCR)-based techniques in oysters (Crassostrea rhizophorae) obtained from the southern coastal region of Bahia, Brazil. A total of 624 oysters were collected, and the gills and digestive glands were dissected. Each tissue sample was separated into pools containing tissues (of the same type) from three animals, leading to a total of 416 experimental samples for analysis (208 samples each from the gills and digestive glands). Molecular analysis using PCR-based detection of the T. gondii AF 146527 repetitive fragment yielded negative results for all samples. However, when nested-PCR was used for detection of the T. gondii SAG-1 gene, 17 samples were positive, with the gills being the tissue with maximal detection of the parasite. These positive results were confirmed by sample sequencing. It is therefore suggested that C. rhizophorae oysters are capable of filtering and retaining T. gondii oocysts in their tissue. This represents a risk to public health because they are traditionally ingested in natura.

  2. 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.

  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.

  4. 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. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Comparison of the antioxidant defense system in Crassostrea rhizophorae and Crassostrea gigas exposed to domestic sewage discharges.

    PubMed

    Zanette, Juliano; Nunes, Fabrício Flores; Medeiros, Igor Dias; Siebert, Marília Nardelli; Mattos, Jacó Joaquim; Lüchmann, Karim Hahn; Rodrigues de Melo, Cláudio Manoel; Bainy, Afonso Celso Dias

    2008-07-01

    Oysters Crassostrea rhizophorae and Crassostrea gigas were kept for fourteen days at four sites in São José, SC, Brazil, chosen according to a sewage discharge contamination gradient. Enzymatic activities of CAT, GST, G6PDH and GR were evaluated in gills and digestive glands. Higher CAT activity was observed in tissues of C. rhizophorae in response to sewage contamination possibly indicating peroxisome proliferation induction. C. gigas showed elevated G6PDH activity in digestive gland, and GR in gills, after domestic sewage exposure. In conclusion, C. rhizophorae and C. gigas showed different biochemical responses after in situ exposure to domestic sewage. However, C. rhizophorae showed more significant changes in CAT suggesting that this organism could be a better monitor to this kind of effluent.

  6. Influence of seasonality on the chemical composition of oysters (Crassostrea rhizophorae).

    PubMed

    Lira, Giselda M; Pascoal, Jadna C M; Torres, Elizabeth A F S; Soares, Rosana A M; Mendonça, Simone; Sampaio, Geni R; Correia, Meiryellen S; Cabral, Caterine C V Q; Cabral Júnior, Cyro R; López, Ana M Q

    2013-06-01

    This paper aimed to evaluate the influence of seasonality on the chemical composition of oysters (Crassostrea rhizophorae). Samples were collected during summer and winter from the estuary and lagoon complex of the municipality of Barra de São Miguel, Alagoas, Brazil. Statistical differences (p<0.05) between summer and winter were observed in relation to chemical composition. The oysters cultivated in the winter presented some nutritional advantages because of the higher levels of proteins and functional nutrients, such as the eicosapentaenoic-docosahexaenoic acid combination and percentages of polyunsaturated fatty acids (n-3 and n-6), and the lower levels of saturated fatty acids. Therefore, the animals in winter presented a higher content of cholesterol oxides. The levels of cholesterol oxides found in these products during winter may encourage researchers to investigate the composition of oysters cultivated in different climates all over the world. Copyright © 2012. Published by Elsevier Ltd.

  7. Aspects of mitochondrial activity in the estuarine bivalves Crassostrea rhizophorae and Lucina pectinatus: a comparative approach.

    PubMed

    Nascimento, I A; Erlon, L; Rodrigues, A

    1976-12-01

    In identical laboratory conditions, some differences in the endogenous relative activity (mul O2/mg protein/ml/h) were determined by the addition of succinate and alpha-keto-glutarate to the mitochondrial-rich-fraction from heart and both parts of the adductor muscle in oyster (Crassostrea rhizophorae) and from heart and adductor muscle in clams (Lucina pectinatus).

  8. 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

    2015-11-10

    AbstractThe 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.

  9. 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.

  10. 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

  11. Biomonitoring of trace metal contamination in the Potengi estuary, Natal (Brazil), using the oyster Crassostrea rhizophorae, a local food source.

    PubMed

    Silva, C A; Rainbow, P S; Smith, B D; Santos, Z L

    2001-12-01

    The oyster Crassostrea rhizophorae was collected in September 1997 from 10 stations along the Potengi estuary, Natal, Brazil, a mangrove-lined estuary receiving anthropogenic inputs of trace metals. C. rhizophorae is a net accumulator of trace metals and can be used as a biomonitor, the accumulated soft tissue concentrations representing integrated records of bioavailable metal fractions over the life of the oyster. Significant differences in oyster accumulated concentrations (and hence bioavailabilities) of Fe, Zn, Cu, Cr, Pb, Cd, Ni and Ag (but not Mn) were found between stations, and attributed to anthropogenic inputs including discharges of sewage and industrial effluent. The oysters are also a local food source, and concentrations of zinc, copper and lead in some of the oysters are above typical public health recommended limits.

  12. Copper, zinc and lead enrichments in sediments from Guacanayabo Gulf, Cuba, and its bioaccumulation in oysters, Crassostrea rhizophorae.

    PubMed

    Díaz Rizo, O; Olivares Reumont, S; Viguri Fuente, J; Díaz Arado, O; López Pino, N; D'Alessandro Rodríguez, K; de la Rosa Medero, D; Gelen Rudnikas, A; Arencibia Carballo, G

    2010-01-01

    Levels of iron, copper, zinc and lead were determined in sediments and soft tissue of the oyster Crassostrea rhizophorae collected from Guacanayabo Gulf, Cuba. Metal-to-Iron ratio in sediments shows an average enrichment for Cu (5,1), Pb (11,7) and Zn (1,3) in the last 20 years. Metal concentrations found in soft tissue of C. rhizophorae are site dependent. The average biota-sediment accumulation factors (BSAFs) obtained for Fe, Cu and Pb are less than unity in all cases, indicating that only a little fraction of Cu and Pb in the sediments is bioavailable, independently of their enrichments. Zinc has an average BSAF value of 2.4 and may represent a serious impact in the area. The concentrations of zinc and copper in some of the oysters are above typical public health recommended limits.

  13. [Reproductive cycle of the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae) in Camamu Bay, Bahia, Brasil].

    PubMed

    Lenz, Tiago; Boehs, Guisla

    2011-03-01

    The mangrove oyster Crassostrea rhizophorae is important fishery resource along the entire Brasilian coast with excellent potential for marine culture. The purpose of this paper was to examine the reproductive characteristics of the oyster of the Maraú river estuary in Camamu Bay, Bahia, Brasil. The samples were collected monthly, from September 2006 to August 2007, at two points (I and II) in Camamu Bay. At each site 20 oysters were collected for histological analysis, fixed in Davidson's solution, embedded in paraffin, dehydrated in an ethanol series, sectioned (7 microm thick) and stained with Harris hematoxylin and Eosin (HE). Additionally, 30 oysters were sampled, at each point, for a condition index analysis. The water temperature ranged from 23.5 degrees C to 30 degrees C and the salinity from 15 to 25 ups at Point I (Maraú) and from 25 to 35 at Point II (Tanque Island). The oyster's height ranged from 30 to 92 mm at Point I and from 27 to 102 mm at Point II, with an average of 49.0 mm +/- 9.1 (n = 230) and 49.9 mm +/- 9.9 (n = 237), respectively. Among the sampled oysters at Point I, 59.1% were females, 31.3% males, 1.3% hermaphrodites and 8.2% of the oysters of undetermined sex. At Point II, 66.2% were females, 30.4% males, 0.8% hermaphrodites and 2.5% (n = 237) of undetermined sex. The gonadic stage analysis indicated that the reproduction period of the C. rhizophorae in the Maraú Peninsula was continuous all year, without any regressive phase. The condition index (R) ranged from 8.0% to 17.7%. The peak periods of R coincided with the expressive oyster's percentage in the maturation and liberation gametic stages. The results of these findings will contribute information for the oyster spat collection and to the process installation of the oyster culture in Camamu Bay.

  14. Polymorphic microsatellite loci for two Atlantic oyster species: Crassostrea rhizophorae and C. gasar.

    PubMed

    Cavaleiro, Nathalia P; Solé-Cava, Antonio M; Lazoski, Cristiano; Cunha, Haydée A

    2013-12-01

    Using a CA/CAA enriched library screening procedure, we isolated and characterised a total of seventeen polymorphic microsatellite loci for two species of Crassostrea with recognised economic importance. Eleven microsatellite loci were developed for C. rhizophorae, a Western Atlantic species for which no microsatellites were previously known. Another six loci were developed for C. gasar, a species that occurs on both sides of the South Atlantic, adding to the ten loci previously described for the species. The levels of polymorphism were estimated using 24 C. rhizophorae from Southeast Brazil (São Paulo) and 23 C. gasar individuals from North Brazil (Maranhão). The number of alleles per polymorphic locus varied from 3 to 27, and the observed and expected heterozygosities ranged between 0.174 and 0.958 and between 0.237 and 0.972 in C. rhizophorae and C. gasar, respectively. No linkage disequilibrium was found between any locus pair, and four of them exhibited deviations from Hardy-Weinberg expectations. Of the 17 loci developed, 8 cross-amplified in C. gigas and 13 in C. virginica. These markers are useful for evolution and population genetics studies of Crassostrea species and may provide fundamental data for the future cultivation of native oysters in Western Atlantic.

  15. Health assessment of the oyster Crassostrea rhizophorae on the southern coast of Bahia, northeastern Brazil.

    PubMed

    Brandão, Rosana Pinho; Boehs, Guisla; Silva, Patrícia Mirella da

    2013-01-01

    This study investigated the health of natural stocks of the oyster Crassostrea rhizophorae on the southern coast of Bahia in northeastern Brazil, during summer and winter 2010, at three localities (sampling points) in the estuaries of the Maraú (Camamu Bay) and Graciosa rivers. A total of 180 oysters (30/sampling point/season) were examined macroscopically for the presence of pathogens and anatomical changes. The specimens were subsequently fixed in Davidson solution, processed for paraffin embedding, sectioned and stained with Harris' hematoxylin and eosin. Histological analysis revealed the presence of Rickettsia-like organisms (RLOs), Ancistrocoma, Trichodina, Sphenophrya, Nematopsis, Urastoma, Bucephalus in the sporocyst phase, a nonspecific metacercaria, and a metacestode of genus Tylocephalum. The prevalence of infection was low except for parasitism by Nematopsis sp. which also caused histopathological changes. The presence of Bucephalus sp. caused parasitic castration. These two pathogens significantly affect the health of C. rhizophorae.

  16. Effects of furadan in the brown mussel Perna perna and in the mangrove oyster Crassostrea rhizophorae.

    PubMed

    Alves, Sandra R C; Severino, Patricia C; Ibbotson, Dominique P; da Silva, Angela Z; Lopes, Franklin R A S; Sáenz, Luis A; Bainy, Afonso C D

    2002-01-01

    Furadan is a carbamate pesticide used widely to combat agricultural pests. However little information is available about the toxicity of furadan in aquatic macroinvertebrates. The in vivo effects of furadan were evaluated in mussels, Perna perna, and oysters, Crassostrea rhizophorae. Glutathione S-transferase (GST), catalase (CAT) and cholinesterase (ChE) activities were measured in the gills of both species exposed to furadan (100 microg/l) for 96 h. No changes were observed in GST activity in the exposed groups. CAT activity was higher (9%) in the oysters exposed to furadan. ChE activity was inhibited by 64 and 35%, respectively, in C. rhizophorae and P. perna exposed to furadan, suggesting that the former is more susceptible to the toxic effects of furadan.

  17. First record of Perkinsus chesapeaki infecting Crassostrea rhizophorae in South America.

    PubMed

    Dantas Neto, Maximiano Pinheiro; Gesteira, Tereza Cristina Vasconcelos; Sabry, Rachel Costa; Feijó, Rubens Galdino; Forte, Jamille Martins; Boehs, Guisla; Maggioni, Rodrigo

    2016-11-01

    This study investigated Perkinsus spp. infecting Crassostrea rhizophorae from the Jaguaribe River estuary, Ceará, Brazil. Fragments of gills and rectum of the oysters (n=150) were incubated in Ray's fluid thioglycollate medium (RFTM). Genus Perkinsus-specific PerkITS85/750 PCR assays were performed and their amplicons were sequenced by the Sanger method. The RFTM assays confirmed Perkinsus spp. The sequencing of the amplified fragments from the rDNA internal transcribed spacers (ITS) of Perkinsus spp. confirmed Perkinsus chesapeaki. Neighbor-Joining analyzes place P. chesapeaki identified in this study in a well-supported clade with other isolates of the same species. This is the first record of P. chesapeaki infecting C. rhizophorae in South America. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Biochemical biomarkers in gills of mangrove oyster Crassostrea rhizophorae from three Brazilian estuaries.

    PubMed

    Zanette, Juliano; Monserrat, José Maria; Bianchini, Adalto

    2006-06-01

    Responses of biochemical biomarkers were evaluated in gills of immature adult mangrove oyster Crassostrea rhizophorae collected in three estuarine regions along the Brazilian coast. In each region, ten oysters were collected in one reference site (R) located far from pollution sources, and in two polluted sites (P-I and P-II sites) located in another water body with similar characteristics. P-I site is located close to recognized pollution sources while P-II site is in the same water body, but far from pollution sources. At the Paranaguá Bay (Southern Brazil), polluted sites receive domestic, harbor and phosphate fertilizer plant discharges. High lipid peroxides (LPO) content was observed in winter oysters from the P-I site. In summer, higher catalase activity was observed in these oysters. In the Piraquê region (Southeastern Brazil), polluted sites receive domestic and agricultural effluents. Lower total oxyradical scavenging capacity (TOSC) towards peroxyradicals was observed in summer oysters from both P-I and P-II sites. In the Itamaracá region (Northeastern Brazil), polluted sites receive paper mill and caustic soda and chlorine factories effluents. Increased glutathione S-transferase (GST) activity was observed in oysters from the P-I site in both summer and winter. At Paranaguá Bay (higher latitude), no seasonal differences were observed in oysters from the R site, suggesting that temperature was not an important factor influencing biomarkers levels. Lower GST activity was observed in oysters from the R site of the Itamaracá Bay (lower latitude) in winter and summer. Taken together, data obtained point to responses of biomarkers in oysters from polluted sites of the three estuarine regions analyzed, indicating the need for future monitoring of the biological effects of contaminants in these environments. They also point to the relevance to consider both season and latitude as factors influencing biomarker responses in environmental contamination

  19. Cloning and detection of metallothionein mRNA by RT-PCR in mangrove oysters (Crassostrea rhizophorae).

    PubMed

    Rebelo, Mauro F; Pfeiffer, Wolfgang C; da Silva, Hamilton; Moraes, Milton O

    2003-08-20

    A semi-quantitative RT-PCR protocol was developed to directly evaluate metallothionein (MT) mRNA expression in different tissues of mangrove oysters (Crassostrea rhizophorae), using beta-Actin (ACT) as a normalizing gene. Clones with high degree of identity from partial coding sequences were obtained for both MT and ACT. Although not statistically significant, high relative accumulation of MT mRNA was observed in the digestive gland (DGG), but not in the gills, from samples collected from both control and contaminated sites. Nevertheless, MT expression was not comparable to the high levels of metal in the contaminated oysters. Results indicate that the variation in relative MT mRNA levels from different samples of the same site could be due to multiple gene copies or different MT isoform induction.

  20. Metals in sediments and mangrove oysters (Crassostrea rhizophorae) from the Caroni Swamp, Trinidad.

    PubMed

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

    2014-03-01

    Metals can have significant impacts on inhabitants of mangrove swamps as well as consumers of mangrove-associated fauna. Yet, for several Caribbean islands, assessments regarding the impact of metals on such ecosystems are particularly sparse. The present study investigated the distribution and potential impact of Cd, Cr, Cu, Ni, Pb and Zn in the Caroni Swamp, Trinidad and Tobago's largest mangrove ecosystem. Surface sediments and mangrove oysters (Crassostrea rhizophorae) from 10 sites in the swamp were analysed for the 6 identified metals. The concentration ranges (in μg/g dry wt.) of metals in sediments from Caroni Swamp were: Zn (113.4-264.6), Cr (27-69.7), Ni (10.7-41.1) and Cu (11-40.7). Based on Canadian Sediment Quality Guidelines (CSQGs), metals in sediments posed a low to medium risk to aquatic life. The concentration ranges (in μg/g wet wt.) for metals in Crassostrea rhizophorae tissues were: Zn (123.2-660), Cu (4.2-12.3), Ni (0.1-5.5), Pb (0.1-0.9), Cr (0.2-0.3) and Cd (0.1-0.2). Multiple evaluations indicated that zinc posed a potential threat to the health of oyster consumers. Information from this study is vital for managing the Caroni Swamp, safeguarding the health of consumers of shellfish on this Caribbean island and serving as a useful baseline for future local and regional risk assessments.

  1. Microbiological Quality and Prevalence of β-Lactam Antibiotic Resistance Genes in Oysters ( Crassostrea rhizophorae ).

    PubMed

    Brandão, Maria Aparecida da RessurreiÇão; Lopes, Amanda Teixeira Sampaio; Neta, Maria Tereza da Silva; de Oliveira, Rhyan Barros Farias; Rezende, Rachel Passos; Albuquerque, George Rêgo; Gonçalves, Verônica Dias; Rodrigues, Dália Dos Prazeres; Boehs, Guisla; Maciel, Bianca Mendes

    2017-03-01

    The microbiological quality of oysters reflects the microbiological quality of their habitats because they are filter feeders. The objective of this study was to assess the bacterial composition of the edible oyster Crassostrea rhizophorae in urban and preserved estuaries. Particularly, we assessed the presence of pathogenic bacteria, investigated antibiotic susceptibility in bacterial isolates, and quantified β-lactam antibiotic resistance genes (blaTEM, blaSHV, and blaKPC) via quantitative PCR of oyster DNA. Our results detected total coliforms, Escherichia coli , and enterobacteria in the oysters from urban estuaries, which is indicative of poor water quality. In addition, our detection of the eaeA and stxA2 virulence genes in 16.7% of E. coli isolates from oysters from this region suggests the presence of multiantibiotic-resistant enteropathogenic and enterohemorrhagic E. coli strains. During periods of low precipitation, increased contamination by E. coli (in winter) and Vibrio parahaemolyticus (in autumn) was observed. In contrast, cultivated oysters inhabiting monitored farms in preserved areas had low levels of bacterial contamination, emphasizing that oyster culture monitoring enhances food quality and makes oysters fit for human consumption. Distinct antibiotic resistance profiles were observed in bacteria isolated from oysters collected from different areas, including resistance to β-lactam antibiotics. The presence of the blaTEM gene in 91.3% of oyster samples indicated that microorganisms in estuarine water conferred the capability to produce β-lactamase. To our knowledge, this is the first study to directly quantify and detect β-lactam antibiotic resistance genes in oysters. We believe our study provides baseline data for bacterial dynamics in estuarine oysters; such knowledge contributes to developing risk assessments to determine the associated hazards and consequences of consuming oysters from aquatic environments containing pathogenic bacteria

  2. 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. Copyright © 2015. Published by Elsevier Inc.

  3. 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.

  4. New Insights from the Oyster Crassostrea rhizophorae on Bivalve Circulating Hemocytes

    PubMed Central

    Mariante, Rafael M.; Nóbrega, Alberto; de Barros, Cintia Monteiro; Allodi, Silvana

    2013-01-01

    Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae. Transmission electron microscopy revealed remarkable morphological characteristics, such as the presence of membranous cisternae in all mature cells, regardless of size and granulation. Some granular cells contained many cytoplasmic granules that communicated with each other through a network of channels, a feature never previously described for hemocytes. The positive reactions for esterase and acid phosphatase also indicated the presence of mature cells of all sizes and granule contents. Flow cytometry revealed a clear separation in complexity between agranular and granular populations, which could not be differentiated by size, with cells ranging from 2.5 to 25 µm. Based on this evidence we suggest that, at least in C. rhizophorae, the different subpopulations of hemocytes may in reality be different stages of one type of cell, which accumulates granules and loses complexity (with no reduction in size) as it degranulates in the event of an environmental challenge. PMID:23451217

  5. Accumulation and elimination of trace metals in a transplantation experiment with Crassostrea rhizophorae.

    PubMed

    Wallner-Kersanach, M; Theede, H; Eversberg, U; Lobo, S

    2000-01-01

    Oysters, Crassostrea rhizophorae, were reciprocally transplanted to two different sites: a contaminated site in the Cotegipe Channel at Aratu Bay and an uncontaminated site at Cacha-Prego, inside and outside of Todos os Santos Bay (Brazil), respectively. Trace metal accumulation was measured after 0, 15, 30, and 60 days of exposure at the contaminated site. Oysters transplanted for 60 days from the clean to the contaminated site had accumulated cadmium and lead to similar concentrations as found in the native oysters. They had also accumulated copper and zinc, but to lower levels compared to native specimens. Elimination experiments were carried out by transplanting oysters in the reverse direction. After 30 days, concentrations of cadmium and lead had decreased to levels comparable to those in the native specimen, whereas concentrations of copper and zinc did not diminish. A second elimination experiment, bringing back to Cacha-Prego oysters that had been exposed 60 days at Cotegipe Channel, indicated stronger decreases of copper and lead, but no clear changes of cadmium and zinc concentrations. The accumulation experiment with C. rhizophorae is useful to estimate trace metal bioavailability and changes in concentrations as a function of time at the contaminated site. The different results of elimination experiments in the uncontaminated site suggest different degrees of trace metal fixation after long-term and short-term accumulation periods.

  6. New insights from the oyster Crassostrea rhizophorae on bivalve circulating hemocytes.

    PubMed

    Rebelo, Mauro de Freitas; Figueiredo, Eliane de Souza; Mariante, Rafael M; Nóbrega, Alberto; de Barros, Cintia Monteiro; Allodi, Silvana

    2013-01-01

    Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae. Transmission electron microscopy revealed remarkable morphological characteristics, such as the presence of membranous cisternae in all mature cells, regardless of size and granulation. Some granular cells contained many cytoplasmic granules that communicated with each other through a network of channels, a feature never previously described for hemocytes. The positive reactions for esterase and acid phosphatase also indicated the presence of mature cells of all sizes and granule contents. Flow cytometry revealed a clear separation in complexity between agranular and granular populations, which could not be differentiated by size, with cells ranging from 2.5 to 25 µm. Based on this evidence we suggest that, at least in C. rhizophorae, the different subpopulations of hemocytes may in reality be different stages of one type of cell, which accumulates granules and loses complexity (with no reduction in size) as it degranulates in the event of an environmental challenge.

  7. Effects of salinity on biomarker responses in Crassostrea rhizophorae (Mollusca, Bivalvia) exposed to diesel oil.

    PubMed

    da Silva, Angela Zaccaron; Zanette, Juliano; Fernando Ferreira, Jaime; Guzenski, João; Marques, Maria Risoleta Freire; Bainy, Afonso Celso Dias

    2005-11-01

    Crassostrea rhizophorae is a euryhaline oyster that inhabits mangrove areas, which are widely distributed along the Brazilian coast. The aim of this study was to investigate the effects of salinity (9, 15, 25, and 35ppt) on the activities of glutathione S-transferase (GST), glucose 6-phosphate dehydrogenase (G6PDH), catalase (CAT), and acetylcholinesterase (AChE) in the digestive gland of this species after exposure to diesel oil for 7 days at nominal concentrations of 0.01, 0.1, and 1mlL(-1) and after depuration for 24h and 7 days. GST activity increased in a diesel oil concentration-dependent manner at salinities 25 and 15ppt and remained slightly elevated even after depuration periods of 24h and 7 days. No changes were observed in the activities of G6PDH, CAT, and AChE in the oysters exposed to diesel and depurated. Based on these results, GST activity in the digestive gland of C. rhizophorae might be used as a biomarker of exposure to diesel oil in sites where the salinity is between 15 and 25ppt, values usually observed in mangrove ecosystems.

  8. Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia.

    PubMed

    Cova, Aliane Watanabe; Serafim Júnior, Moacyr; Boehs, Guisla; Souza, Jackson Moreira de

    2015-01-01

    In this work, parasites associated with the mangrove oyster Crassostrea rhizophorae were studied at a cultivation unit in the estuary of the Graciosa River in Taperoá, Bahia. On a monthly basis, between April 2011 and March 2012, 20 oysters were collected, measured and fixed in 10% formaldehyde. In order to identify the parasites, routine histological techniques were used. The specimens were embedded in paraffin and sections, 7 µm thick, were cut. These were then stained with Harris hematoxylin and eosin and were examined using an optical microscope. The parameters analyzed to investigate water quality showed that the temperature ranged from 23.9 °C to 29.3 °C, water salinity from 0.4 to 24.2 Practical Salinity Units PSU and recorded rainfall from 80 mm to 406.4 mm/month. During the parasitological analyses, infestation of the polychaete Neanthes succinea was observed in 41% of the oysters. Through histological techniques, the following parasites were identified: colonies of Rickettsia-like organisms (RLOs); the protozoa Nematopsis sp. and Ancistrocoma sp.; the turbellarian Urastoma sp.; the metacestode Tylocephalum sp. and an unidentified tapeworm. The data collected showed that there was low-intensity infection with and prevalence of parasites, except for Nematopsis sp., thus attesting that these cultivated oysters were in a healthy condition.

  9. Chemical contamination assessment in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as biomonitor species.

    PubMed

    Aguirre-Rubí, Javier R; Luna-Acosta, Andrea; Etxebarría, Nestor; Soto, Manu; Espinoza, Félix; Ahrens, Michael J; Marigómez, Ionan

    2017-05-24

    This paper aims to contribute to the use of mangrove cupped oyster, Crassostrea rhizophorae, as a biomonitor species for chemical contamination assessment in mangrove-lined Caribbean coastal systems. Sampling was carried out in eight localities (three in Nicaragua and five in Colombia) with different types and levels of contamination. Oysters were collected during the rainy and dry seasons of 2012-2013 and the tissue concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) were determined. Low tissue concentrations of metals (except Hg) and PAHs; moderate-to-high tissue concentrations of Hg, hexachlorocyclohexanes (HCHs), and dichlorodiphenyl-trichloroethanes (DDTs); detectable levels of chlorpyrifos, polychlorinated biphenyls (PCBs) (mainly CB28, CB118, CB138 and CB 153) and brominated diphenyl ethers 85 (BDE85); and negligible levels of musks were recorded in Nicaraguan oysters. A distinct profile of POPs was identified in Colombia, where the tissue concentrations of PCBs and synthetic musk fragrances were low to moderate, and Ag, As, Cd, Pb, and PAHs ranged from moderate to extremely high. Overall, the values recorded for HCHs, DDTs and PCBs in Nicaraguan mangrove cupped oysters greatly exceeded the reference values in tissues of C. rhizophorae from the Wider Caribbean Region, whereas only the levels of PCBs were occasionally surpassed in Colombia. Different contaminant profiles were distinguished between oysters from Nicaragua and Colombia in radar plots constructed using the main groups of contaminants (metals, PAHs, musks, PCBs, and organochlorine pesticides (OCPs)). Likewise, integrated pollution indices revealed differences in the levels of contaminants. Moreover, the profiles and levels in oyster tissues also varied with season. Thus, principal component analysis clearly discriminated Nicaraguan and Colombian localities and, especially in Colombia, seasonal trends in chemical contamination and differences

  10. First report of Cryptosporidium spp. oocysts in oysters (Crassostrea rhizophorae) and cockles (Tivela mactroides) in Brazil.

    PubMed

    Guiguet Leal, Diego Averaldo; Pereira, Mirna Aparecida; Bueno Franco, Regina Maura; Branco, Nilson; Neto, Romeu Cantusio

    2008-12-01

    The consumption of oysters and cockles, which are usually eaten raw or lightly-cooked, can cause outbreaks of human diseases, especially if these shellfish are harvested from polluted areas. In Brazil data about the occurrence of pathogens, like hepatitis A virus, in shellfish have been reported but research on natural contamination for pathogenic protozoa is still non-existent. Cryptosporidium oocyst contamination of oysters (Crassostrea rhizophorae) and cockles (Tivela mactroides) was evaluated during two different periods in a coastal area from São Paulo, Brazil. From June to November 2005, and from July to December 2006, 180 mollusks were harvested for tissue examination. The gills and gastrointestinal tract (n = 36 pools) were carefully extracted from the animals and homogenized in a tissue homogenizer by adding surfactant Tween 80 (0.1%). Immunofluorescence assays were performed and Cryptosporidium oocysts were detected in 50.0% of gill pools of cockles and 10.0% of gill pools of oysters. In order to evaluate seawater quality in shellfish growing areas, total levels of thermotolerant coliforms, Escherichia coli and enterococci were determined. This is the first time that Cryptosporidium oocysts were found in shellfish from the coastal region of Brazil, and to the best of our knowledge it is also the first report in Latin America and the case might be of public health importance, reflecting the extension of the contamination on seafood, requiring a need for quality control standards. Copyright IWA Publishing 2008.

  11. [Pathogenic Vibrios in oysters (Crassostrea rhizophorae) served at restaurants in Rio de Janeiro: a public health warning].

    PubMed

    Pereira, Christiane Soares; Viana, Célio Mauro; Rodrigues, Dália dos Prazeres

    2007-01-01

    Forty oyster samples (Crassostrea rhizophorae) served raw in 15 restaurants in the city of Rio de Janeiro were evaluated in order to investigate the presence of Vibrio spp. The oyster samples were analyzed and subjected to enrichment in alkaline peptone water with the addition of 1 and 3% NaCl and incubated at 37 degrees C for 24 hours. Following this, the cultures were seeded onto thiosulfate citrate bile sucrose agar (TCBS) and the suspected colonies were subjected to biochemical characterization. Vibrio parahaemolyticus, Vibrio carchariae, Vibrio alginolyticus and Vibrio vulnificus were the main species (> 60%) isolated from raw oysters.

  12. Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon.

    PubMed

    Rebouças do Amaral, Maria Clara; de Freitas Rebelo, Mauro; Torres, João Paulo Machado; Pfeiffer, Wolfgang Christian

    2005-05-01

    In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.

  13. Microbiological quality and bacterial diversity of the tropical oyster Crassostrea rhizophorae in a monitored farming system and from natural stocks.

    PubMed

    Silva Neta, M T; Maciel, B M; Lopes, A T S; Marques, E L S; Rezende, R P; Boehs, G

    2015-12-02

    Microbiological evaluation is one of the most important parameters for analyzing the viability of an oyster farming system, which addresses public health and ecological concerns. Here, the microbiological quality of the oyster Crassostrea rhizophorae cultivated in a monitored environment and from natural beds in Bahia, northeastern Brazil, was determined. Bacterial diversity in oysters was measured by polymerase chain reaction-denaturing gradient gel electrophoresis. Sequence analysis revealed that most bacterial species showed similarity with uncultured or unidentified bacteria from environmental samples, and were clustered into the phylum Proteobacteria. Diverse bacteria from cultivated (monitored) oyster samples were grouped in the same cluster with a high similarity index (above 79%). Microbiological analyses revealed that these oysters did not contain pathogens. These results reflect the natural balance of the microbial communities essential to the maintenance of health and in inhibiting pathogen colonization in the oyster. On the other hand, bacterial diversity of samples from native stocks in extractive areas displayed a similarity index varying between 55 and 77%, and all samples were clustered separately from each other and from the cluster of samples derived from the cultivation area. Microbiological analyses showed that oysters from the extractive area were not fit for human consumption. This reflected a different composition of the microbial community in this area, probably resulting from anthropic impact. Our study also demonstrated that low temperatures and high rainfall limits the bacterial concentration in tropical oysters. This is the first study analyzing the total bacterial community profiles of the oyster C. rhizophorae.

  14. Hemolymph and gill carbonic anhydrase are more sensitive to aquatic contamination than mantle carbonic anhydrase in the mangrove oyster Crassostrea rhizophorae.

    PubMed

    Dos Santos, Matheus Barbosa; Monteiro Neto, Ignácio Evaristo; de Souza Melo, Sarah Rachel Candido; Amado, Enelise Marcelle

    2017-09-06

    Carbonic anhydrase (CA) is a ubiquitous metalloenzyme of great importance in several physiological processes. Due to its physiological importance and sensitivity to various pollutants, CA activity has been used as biomarker of aquatic contamination. Considering that in bivalves the sensitivity of CA to pollutants seems to be tissue-specific, we proposed here to analyze CA activity of hemolymph, gill and mantle of Crassostrea rhizophorae collected in two tropical Brazilian estuaries with different levels of anthropogenic impact, in dry and rainy season. We found increased carbonic anhydrase activity in hemolymph, gill and mantle of oysters collected in the Paraíba Estuary (a site of high anthropogenic impact) when compared to oysters from Mamanguape Estuary (inserted in an area of environmental preservation), especially in the rainy season. CA of hemolymph and gill were more sensitive than mantle CA to aquatic contamination. This study enhances the suitability of carbonic anhydrase activity for field biomarker applications with bivalves and brings new and relevant information on hemolymph carbonic anhydrase activity as biomarker of aquatic contamination. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. First record of parasitism in the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae) at Jaguaribe River estuary--Ceará, Brazil.

    PubMed

    Sabry, R C; Gesteira, T C V; Boehs, G

    2007-11-01

    Mangrove oysters Crassostrea rhizophorae were sampled monthly in the estuary of Jaguaribe River, on the east coast of Ceará State, Brazil, between August, 2000 and December, 2001, making up 170 individuals. The water temperature varied from 26 to 30 degrees C and salinity from 21 to 42. The animals' size ranged from 3.4 to 7.2 cm height. Macroscopical and histopathological analyses were carried out in the oysters' tissues. The histological exams showed protozoans and metazoans of genera Nematopsis and Tylocephalum, respectively. Nematopsis prevalence varied from 60 to 100% and it was higher in the gills and mantle. The oocysts presented a mean size of 11.5 microm (+/-1.32) length and 9.1 microm (+/-1.06) width (n = 30), up to 3 oocysts/phagocyte having been observed. Several animals presented focal hemocitical reaction. The percentage of Tylocephalum was 1.7%. In spite of the high infection prevalence by Nematopsis, infected animals did not have their reproductive cycle impaired.

  16. Kinetic and toxicological characteristics of acetylcholinesterase from the gills of oysters (Crassostrea rhizophorae) and other aquatic species.

    PubMed

    Monserrat, J M; Bianchini, A; Bainy, A C D

    2002-01-01

    The aim of this work was to characterize the cholinesterases from gills of Crassostrea rhizophorae in order to use them as biomarkers. Gills were homogenized and then centrifuged (9,000 x g, 4 degrees C, 30 min). S9 and Triton X-100 S9 treated (TX S9) fractions were employed as enzyme source. Km(ap) and Vmax were estimated, using acetylthiocholine iodide as substrate. Inhibition assays were performed with iso-OMPA and eserine. The Km(ap) for S9 and TX S9 fractions were 0.05 and 0.06 mM, whereas the Vmax were 1.92 and 5.84 nmol/min/mg protein. respectively. No inhibition was detected when the samples were incubated with iso-OMPA, suggesting the presence of acetylcholinesterases (AChE) in oyster gill homogenates. Sensitivity to eserine inhibition of AChE in the gills of oysters is intermediate when compared with other aquatic species.

  17. 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. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Oyster condition index in Crassostrea rhizophorae (Guilding 1828) from a heavy-metal polluted coastal lagoon.

    PubMed

    Rebelo, M F; Amaral, M C R; Pfeiffer, W C

    2005-05-01

    The condition index (CI) of oysters represents an ecophysiological approach to estimate meat quality and yield in cultured bivalve mollusks. In the present study, the CI of oysters from a heavy-metal polluted bay was analyzed with respect to Zn and Cd contamination in soft tissues, spawning, and polychaete infestation. The CI was calculated through a new technique based on molds made to measure the volume of oyster-shell internal cavities. The higher CI values (over 9 in the dry season) were probably related availability of suspended particles rich in organic matter in the bay, while the rapid reduction in the CI from one season to the next at some stations suggests the effect of spawning. Polychaete infestation was considered low (18.7%) and produced no clear CI effects. The Cd in the oyster tissue collected during the rainy season was weak, although still significantly correlated with the CI (r = -0.36; p < 0.05). All other comparisons of CI and metal concentrations demonstrated a non-significant correlation. The CI variations observed on the temporal and spatial scale were likely to have been caused by availability of organic matter and spawning, rather than spionid infestation or metal body burdens.

  20. [Accumulation and depuration of aldrin in the oyster Crassostrea rhizophorae, of the Ciénaga Grande de Santa Marta (Colombian Caribbean)].

    PubMed

    Gómez, L C; Campos, N H; Ramírez, G

    1995-01-01

    Laboratory experiments were conducted at different salinities (35, 26 and 17/1000) to determine accumulation and depuration rates of the organochlorine compound aldrin by the oyster Crassostrea rhizophorae, Ciénaga Grande de Santa Marta (Colombian Caribbean). Residual levels were detected in tissues after 24 hours of exposure, showing increases directly related to the exposure concentration. For all the exposure concentrations the highest retention values were measured at 26/1000 salinities, followed by 17/1000, and the lowest values at the highest salinity. The highest bioconcentration values were 96115.5 (at 26/1000), 37938.9 (at 17/1000), and 22605.1, (35/1000) times the environmental concentration. The depuration process varied across salinity levels. At 26/1000 there was a clear decrease in the residual levels during the first five days, eliminating in this period the same amount as oysters kept at 17/1000 for 20 days and surpassing the amount eliminated by those kept at 35/1000 for 20 days. A rapid decrease in the amount of residues is followed by a slow elimination of the aldrin remaining in tissues.

  1. 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

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

    PubMed

    Paixão, J F; Nascimento, I A; Pereira, S A; Leite, M B L; Carvalho, G C; Silveira, J S C; Rebouças, M; Matias, G R A; Rodrigues, I L P

    2007-03-01

    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 24h, 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

  3. 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...

  4. 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...

  5. Rhizophora mangle L

    Treesearch

    James A. Allen

    2002-01-01

    The genus Rhizophora comprises six to eight species and three or four hybrids (Duke 1992, Tomlinson 1986). All members of this pantropical genus are considered true mangroves and are limited in distribution to the intertidal zone. The native range of R. mangle includes the coast of central and southern Florida, Bermuda and most...

  6. [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.

  7. Morphology of the larval shell of three oyster species of the genus Crassostrea Sacco, 1897 (Bivalvia: Ostreidae).

    PubMed

    Christo, S W; Absher, T M; Boehs, G

    2010-08-01

    In this study we describe the morphology of the larval shell of three oyster species of Crassostrea genus. Two species, C. rhizophorae and C. brasiliana, are native to the Brazilian coast, and C. gigas is an introduced species. Samples of laboratory reared larvae, obtained through artificial fertilisation, were collected at intervals during the cultivation process for analysis using Scanning Electron Microscopy (SEM). Prodissoconch morphology was observed in relation to the presence, position, form and number of teeth in the three larval stages: D-shaped larva, umbo larva and pediveliger. Characteristic of D-shaped larvae of C. rhizophorae was the total absence of teeth in the provinculum area while C. brasiliana and C. gigas had two anterior and two posterior teeth in each valve. In the umbo larval phase, the three species had the same number of teeth in each valve: two posterior and two anterior teeth in the right valve and three posterior and three anterior in the left valve. In the pediveliger stage the three species could be differentiated by the number of anterior teeth of the right valve: C. rhizophorae had two teeth, C. brasiliana one tooth and C. gigas three teeth.

  8. Detection of Vibrio parahaemolyticus and Vibrio cholerae in oyster, Crassostrea rhizophorae, collected from a natural nursery in the Cocó river estuary, Fortaleza, Ceará, Brazil.

    PubMed

    de Sousa, Oscarina Viana; Vieira, Regine Helena Silva dos Fernandes; de Menezes, Francisca Gleire Rodrigues; dos Reis, Christiane Moura Falavina; Hofer, Ernesto

    2004-01-01

    Oysters are edible organisms that are often ingested partially cooked or even raw, presenting therefore a very high risk to the consumers' health, especially in tropical regions. The presence of Vibrio cholerae and Vibrio parahaemolyticus in oysters sampled at an estuary in the Brazilian northeastern region was studied, with 300 oysters tested through an 8-months period. The salinity of the water at the sampling point varied between 3% and 27. V. cholerae was the most frequently detected species (33.3% of the samples), and of the 22 V. cholerae isolates, 20 were identified as non-O1/non-O139, with two of the colonies presenting a rough surface and most of remaining ones belonging to the Heiberg II fermentation group. V. parahaemolyticus was isolated from just one of the samples. Other bacteria such as Providencia spp., Klebsiella spp. and Morganella morganii were also isolated.

  9. 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.

  10. [Mollusks associated to the submerged roots of the red mangrove, Rhizophora mangle (L.), in the Gulf of Santa Fe, Sucre State, Venezuela].

    PubMed

    Márquez, B; Jiménez, M

    2002-01-01

    A qualitative and quantitative monthly study of the mollusks community associated to the submerged roots of the red mangrove, Rhizophora mangle (L.), between October of 1998 and September of 1999, in six stations of the Gulf of Santa Fe, (Sucre State, Venezuela). Were collected 4,704 specimens, 45 species of mollusks were identified (22 gastropods, 15 bivalves and 8 chitons). The most abundant species were: Crassostrea rhizophorae, Isognomon bicolar, I. alatus and Brachidontes exustus. The highest values in diversity and evenness, and the smallest dominant values, were in the stations three and four, while the opposed happened in the stations one and two. The analysis of likeness showed that in the first five stations the space variations in the composition of the community are bigger than the temporary variations, while in the station six the temporary differences prevail. They were factors that could be important to determine the structure of the community, as vicinity to other ecosystems and/or specific biological aspects of the species like adaptations to fluctuating conditions, nutritious habits and migration in search of shady and protected atmospheres.

  11. Molecular identification, phylogeny and geographic distribution of Brazilian mangrove oysters (Crassostrea).

    PubMed

    de Melo, Aline Grasielle Costa; Varela, Eduardo Sousa; Beasley, Colin Robert; Schneider, Horacio; Sampaio, Iracilda; Gaffney, Patrick Michael; Reece, Kimberly S; Tagliaro, Claudia Helena

    2010-07-01

    Oysters (Ostreidae) manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI), revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state) to Santos (São Paulo state), and C. rhizophorae from Fortim (Ceará state) to Florianópolis (Santa Catarina state), although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state). An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship.

  12. Molecular identification, phylogeny and geographic distribution of Brazilian mangrove oysters (Crassostrea)

    PubMed Central

    2010-01-01

    Oysters (Ostreidae) manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI), revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state) to Santos (São Paulo state), and C. rhizophorae from Fortim (Ceará state) to Florianópolis (Santa Catarina state), although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state). An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship. PMID:21637433

  13. Strontium and Magnesium in Water and in Crassostrea Calcite.

    PubMed

    Lerman, A

    1965-11-05

    Distribution of magnesium and strontium was determined between waters and calcites secreted by the oyster species Crassostrea virginica and C. rhizophorae in natural habitats at eight localities, from Maine to Puerto Rico. The concentration of strontium in the calcite shells increases with increasing temperature in the range 13 degrees to 25 degrees C, and also with increasing Sr(++)/Ca(++) molal ratio in the water. The concentration of magnesium in the shells increases irregularly with temperature, and it is apparently independent of the Mg(++)/Ca(++) ratio in the water. The greater variation with temperature in the distribution factor for magnesium may be related to genetic differences between semi-isolated populations.

  14. Bacillus crassostreae sp. nov., isolated from an oyster (Crassostrea hongkongensis).

    PubMed

    Chen, Jin-Hua; Tian, Xiang-Rong; Ruan, Ying; Yang, Ling-Ling; He, Ze-Qiang; Tang, Shu-Kun; Li, Wen-Jun; Shi, Huazhong; Chen, Yi-Guang

    2015-05-01

    A novel Gram-stain-positive, motile, catalase- and oxidase-positive, endospore-forming, facultatively anaerobic rod, designated strain JSM 100118(T), was isolated from an oyster (Crassostrea hongkongensis) collected from the tidal flat of Naozhou Island in the South China Sea. Strain JSM 100118(T) was able to grow with 0-13% (w/v) NaCl (optimum 2-5%), at pH 5.5-10.0 (optimum pH 7.5) and at 5-50 °C (optimum 30-35 °C). The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant respiratory quinone was menaquinone-7 and the major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, C16 : 0 and C16 : 1ω11c. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unknown glycolipid and an unknown phospholipid. The genomic DNA G+C content was 35.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 100118(T) belonged to the genus Bacillus , and was most closely related to Bacillus litoralis SW-211(T) (98.9% 16S rRNA gene sequence similarity), Bacillus halosaccharovorans E33(T) (98.3%), Bacillus niabensis 4T19(T) (97.8%) and Bacillus herbersteinensis D-1,5a(T) (97.1%). The combination of results from the phylogenetic analysis, DNA-DNA hybridization, and phenotypic and chemotaxonomic characterization supported the conclusion that strain JSM 100118(T) represents a novel species of the genus Bacillus , for which the name Bacillus crassostreae sp. nov. is proposed. The type strain is JSM 100118(T) ( = CTCC AB 2010452(T) =DSM 24486(T) =JCM 17523(T)).

  15. 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...

  16. 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...

  17. 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.

  18. [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

  19. Isolation of Vibrio cholerae serotype O1 from the eastern oyster, Crassostrea virginica.

    PubMed Central

    Hood, M A; Ness, G E; Rodrick, G E

    1981-01-01

    Two strains of Vibrio cholerae serotype O1 Inaba were isolated from eastern oysters, Crassostrea virginica, collected from estuarine waters in Florida during April 1980. The oyster meats and waters from which the oysters were collected had low fecal coliform counts, and the area had no prior evidence of sewage contamination. PMID:7235700

  20. Diversity and Distribution of Marine Fungi on Rhizophora spp. in Mangroves.

    PubMed

    Sarma, Vemuri Venkateswara

    2012-01-01

    Rhizophora spp. occurring in mangrove habitats are excellent hosts for marine fungi. The morphological adaptations of this host plant provide suitable niche for the marine fungi. This review deals with diversity and ecology of marine fungi occurring on Rhizophora spp. Two hundred and one fungal species have been recorded on Rhizophora plant species consisting of more than ten fungal species specific to this host. In mangroves, no other genus other than Rhizophora accommodates as many as 201 marine fungi. Rhizophora plant species are highly suitable hosts as they show a variety of niches with vertical zonation, specificity, preferential colonization and succession. Thus this host could be considered as one of the important hosts to investigate marine fungi. The current review provides updated information based on the available literature with checklists on diversity and distribution of fungi on Rhizophora spp.

  1. 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.

  2. Densoviruses in oyster Crassostrea ariakensis.

    PubMed

    Kang, Yan-Jun; Huang, Wei; Zhao, A-Li; Lai, Dan-Dan; Shao, Lin; Shen, Yan-Qin; Deng, Xutao; Delwart, Eric; Zhang, Wen

    2017-03-24

    Densoviruses have short ssDNA genomes and mainly infect arthropods. To characterize viral nucleic acid in shellfish, oysters (Crassostrea ariakensis) were analyzed using viral metagenomics. Two large de novo assembled contigs, CaaDV1 and CaaDV2, consisting of nearly complete densovirus genomes (5860 nucleotides (nt) and 4034 nt) with two major ambisense protein coding regions were identified. Several potential non-structural proteins and capsid proteins were encoded by these genomes, but these were divergent from the existing densoviral species. The NS1 protein of the two CaaDVs shared 43.3%~61.5% amino acid identities with the sea star-associated densovirus and cherax quadricarinatus densovirus, with the four species clustering by phylogenetic analysis. This is the first report of densovirus detection in shellfish, increasing the potential host range of densoviruses and the genetic diversity of the genus Ambidensovirus.

  3. [Antimicrobial properties of extracts from Rhizophora mangle L].

    PubMed

    Rojas Hernández, N M; Coto Pérez, O

    1978-01-01

    Aqueous and alcoholic extracts are obtained from the roots, leaves and stems of ruddy mangrove-tree (Rhizophora mangle L.), a very common plant in Cuban coasts and to which different curative properties are attributed in our popular medicine. The inhibitory activity of these extracts on the growth of different human pathogenic organisms, among which are bacteria, fungii and yeasts, is reported. For this determination, a method of diffusion in an agar medium with holes in which 50 ml of each extract in question were poured was used; the size in millimeters of the inhibitory halo found in each species and the concentration of the dilution in broth for Mycobacterium strains are reported.

  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. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  6. 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

  7. Microbiomes of American Oysters (Crassostrea virginica) Harvested from Two Sites in the Chesapeake Bay.

    PubMed

    Ossai, Sylvia; Ramachandran, Padmini; Ottesen, Andrea; Reed, Elizabeth; DePaola, Angelo; Parveen, Salina

    2017-07-27

    In this study, we used 16S rRNA gene amplicons to describe the bacterial microbiota associated with oysters (Crassostrea virginica) and seawater collected from two sites in the Chesapeake Bay. The dominant bacterial groups included those belonging to the order Pelagibacteraceae, family Enterobacteriaceae, and genus Synechococcus The microbiomes varied among oysters from the same site and between the two sites and months. Copyright © 2017 Ossai et al.

  8. 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.

  9. Differences in the rDNA-bearing chromosome divide the Asian-Pacific and Atlantic species of Crassostrea (Bivalvia, Mollusca).

    PubMed

    Wang, Yongping; Xu, Zhe; Guo, Ximing

    2004-02-01

    Karyotype and chromosomal location of the major ribosomal RNA genes (rDNA) were studied using fluorescence in situ hybridization (FISH) in five species of CRASSOSTREA: three Asian-Pacific species (C. gigas, C. plicatula, and C. ariakensis) and two Atlantic species (C. virginica and C. rhizophorae). FISH probes were made by PCR amplification of the intergenic transcribed spacer between the 18S and 5.8S rRNA genes, and labeled with digoxigenin-11-dUTP. All five species had a haploid number of 10 chromosomes. The Atlantic species had 1-2 submetacentric chromosomes, while the three Pacific species had none. FISH with metaphase chromosomes detected a single telomeric locus for rDNA in all five species without any variation. In all three Pacific species, rDNA was located on the long arm of Chromosome 10 (10q)--the smallest chromosome. In the two Atlantic species, rDNA was located on the short arm of Chromosome 2 (2p)--the second longest chromosome. A review of other studies reveals the same distribution of NOR sites (putative rDNA loci) in three other species: on 10q in C. sikamea and C. angulata from the Pacific Ocean and on 2p in C. gasar from the western Atlantic. All data support the conclusion that differences in size and shape of the rDNA-bearing chromosome represent a major divide between Asian-Pacific and Atlantic species of CRASSOSTREA: This finding suggests that chromosomal divergence can occur under seemingly conserved karyotypes and may play a role in reproductive isolation and speciation.

  10. Seasonal variations in the concentrations of metals in Crassostrea corteziensis from Sonora, México.

    PubMed

    García-Rico, L; Tejeda-Valenzuela, L; Burgos-Hernández, A

    2010-08-01

    This study examines seasonal variations in the concentrations of Cd, Cu, Pb, and Hg in experimentally cultured Crassostrea corteziensis, an oyster species known to have high resistance to physical and chemical stressors. The highest levels of Cd (4.92 mg/kg), Cu (3.45 mg/kg), and Pb (0.67 mg/kg) were detected in oyster samples collected during the summer, while Hg concentrations were similar (0.03 to 0.04 mg/kg) throughout all seasons. Results indicate that except for Cd, Crassostrea corteziensis accumulates metals to levels below those recommended by the US. FDA and the Mexican government. For Cd, its concentration correlates more strongly with the temperature of the oyster's environment rather than to the oyster growth cycle.

  11. 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.

  12. Development and characterization of EST-SSR markers in the eastern oyster Crassostrea virginica.

    PubMed

    Wang, Yongping; Guo, Ximing

    2007-01-01

    Simple sequence repeat (SSR) markers were developed from expressed sequence tags (ESTs) in the eastern oyster (Crassostrea virginica). ESTs of the eastern oyster were downloaded from GenBank and screened for SSRs with at least eight units of dinucleotide or five units of tri-, tetra-, penta-, and hexa-nucleotide repeats. The screening of 9101 ESTs identified 127 (1.4%) SSR-containing sequences. Primers were designed for 88 SSR-containing ESTs with good and sufficient flanking sequences. Polymerase chain reaction (PCR) amplification was successful for 71 primer pairs, including 19 (27%) pairs that amplified fragments longer than expected sizes, probably due to introns. Sixty-six pairs that produced fragments shorter than 800 bp were screened for polymorphism in five oysters from three populations via polyacrylamide gels, and 53 of them (80%) were polymorphic. Fifty-three polymorphic SSRs were labeled and genotyped in 30 oysters from three populations via an automated sequencer. Five of the SSRs amplified more than two fragments per oyster, suggesting locus duplication. The remaining 48 SSRs had 2 alleles per individual, including 11 with null alleles. In the 30 oysters analyzed, the SSRs had an average of 9.3 alleles per locus, ranging from 2 to 24. Forty-three loci segregated in a family with 100 progeny, with nine showing significant deviation from Mendelian ratios (three after Bonferroni correction). Seventy percent of the loci were successfully amplified in C. rhizophorae and 34% in C. gigas. This study demonstrates that ESTs are valuable resources for the development of SSR markers in the eastern oyster, and EST-derived SSRs are more transferable across species than genomic SSRs.

  13. RELATIONSHIPS BETWEEN OYSTER (CRASSOSTREA VIRGINICA) DEFENSE MEASUREMENTS AND TISSUE CONTAMINANTS

    EPA Science Inventory

    Bivalve mollusks such as Crassostrea virginica typically inhabit estuaries and coastal areas that are increasingly contaminated with anthropogenic chemicals. Oysters may bioaccumulate large quantities of metals, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCB...

  14. RELATIONSHIPS BETWEEN OYSTER (CRASSOSTREA VIRGINICA) DEFENSE MEASUREMENTS AND TISSUE CONTAMINANTS

    EPA Science Inventory

    Bivalve mollusks such as Crassostrea virginica typically inhabit estuaries and coastal areas that are increasingly contaminated with anthropogenic chemicals. Oysters may bioaccumulate large quantities of metals, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCB...

  15. 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...

  16. 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...

  17. 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

  18. Heavy-metal contamination of the Pacific oysters (Crassostrea gigas) cultured in Deep Bay, Hong Kong

    SciTech Connect

    Wong, M.H.; Choy, C.K.; Lau, W.M.; Cheung, Y.H.

    1981-08-01

    Samples of Pacific oysters, Crassostrea gigas, cultured in Deep Bay, Hong Kong, were collected for analysis of various heavy-metal contents: iron, copper, lead, cadmium, manganese, chromium, and zinc. In general, the gill had the highest metal contents, followed by the mantle, the viscera, with the smallest amount being observed in the adductor muscle. All metal contents obtained in the present study were within the range reported for the same species in areas where heavy-metal pollution is already recognized as a problem. A long-term monitoring program of measuring the contents of various metals in seawater, sediment, and oysters is therefore essential.

  19. Antihypertensive activity of polysaccharide from Crassostrea gigas.

    PubMed

    Wang, Ting; Ding, Jie; Li, Haibo; Xiang, Jingjing; Wen, Ping; Zhang, Qin; Yin, Linliang; Jiang, Wei; Shen, Caie

    2016-02-01

    Water-soluble polysaccharide was extracted from Crassostrea gigas by hydrolysis with flavourzyme and filtered, ultrafiltered and precipitated using absolute ethanol. Sugar composition analysis performed on the C. gigas polysaccharide (CGP) by high performance liquid chromatography indicated that it was comprised primarily of glucose, and its molecular weight was determined using a TSK-GEL G5000PW column to be ∼3.413×10(6) Da. Next, the antihypertensive activity of CGP was evaluated in rats. Hypertension model Wistar rats were divided into three groups and intragastrically treated with physiological saline (negative control group), CGP (treatment group), and captopril (positive control group). CGP treatment led to significant decrease in both systolic and diastolic pressures in the hypertension model Wistar rats. Furthermore, the antihypertensive effect of CGP was comparable with that of captopril. Thus, CGP has antihypertensive effects and can potentially be used as a therapeutic agent for hypertension. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. [Dynamics of soil properties in forests of Rhizophora mangle L. (Rhizophoraceae) in Margarita Island, Venezuela].

    PubMed

    Sánchez-Arias, Luz Esther; Paolini, Jorge; Rodríguez, Jon Paul

    2010-06-01

    Biochemical and microbiological properties of soils can provide information related to ecosystems environmental status. With the aim to determine the response of microbial biomass, and enzymatic and microbial activity in hypersaline (IS > or = 55 ups) and saline (IS<55 ups) mangrove soils exposed to interstitial salinities (IS) greater than 36 ups, these properties were measured in mono-specific forests of Rhizophora mangle at Laguna de la Restinga National Park (Margarita Island, Venezuela). During three seasons (dry, wet and transition), a total of 120 soil samples were collected from ten (5 hypersaline and 5 saline) randomly-selected sites of 1000 m2 each. Four soil samples (400-500 g) per plot were randomly collected with a corer at a depth of 10 cm using a 1 m2 quadrat; each sample consisted in the combination of 8 sub-samples (50-60 g ea.). Physical, chemical, enzymatic, biochemical and microbiological properties of soil samples were determined using standard laboratory protocols. The response of microbial biomass and microbial and enzymatic activity was analyzed taking into account spatial and climatic factors and interstitial salinity. Microbial biomass was linked to each locality conditions, and was not sensitive to seasonal or salinity differences. Microbial activity remained functionally active during the study period and presented variable responses. Dehydrogenase activity proved to be a good indicator for flooded and anoxic environments, and arginine ammonification resulted to be the more sensitive microbial activity to changes in salinity. Regarding enzyme activities, spatial variability was the most widespread response. We did not find a unique general pattern between enzymatic activities and spatio-temporal variation; and only the enzyme phosphatase was negatively affected by salinity. We conclude that microbial populations of mangrove soils and their activities have functional adaptations to flooded and highly-saline environments typical of a

  1. 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.

  2. Transcriptomic analysis of Crassostrea sikamea × Crassostrea angulata hybrids in response to low salinity stress

    PubMed Central

    Yan, Lulu; Su, Jiaqi; Wang, Zhaoping; Yan, Xiwu; Yu, Ruihai; Ma, Peizhen; Li, Yangchun; Du, Junpeng

    2017-01-01

    Hybrid oysters often show heterosis in growth rate, weight, survival and adaptability to extremes of salinity. Oysters have also been used as model organisms to study the evolution of host-defense system. To gain comprehensive knowledge about various physiological processes in hybrid oysters under low salinity stress, we performed transcriptomic analysis of gill tissue of Crassostrea sikamea ♀ × Crassostrea angulata♂ hybrid using the deep-sequencing platform Illumina HiSeq. We exploited the high-throughput technique to delineate differentially expressed genes (DEGs) in oysters maintained in hypotonic conditions. A total of 199,391 high quality unigenes, with average length of 644 bp, were generated. Of these 35 and 31 genes showed up- and down-regulation, respectively. Functional categorization and pathway analysis of these DEGs revealed enrichment for immune mechanism, apoptosis, energy metabolism and osmoregulation under low salinity stress. The expression patterns of 41 DEGs in hybrids and their parental species were further analyzed by quantitative real-time PCR (qRT-PCR). This study will serve as a platform for subsequent gene expression analysis regarding environmental stress. Our findings will also provide valuable information about gene expression to better understand the immune mechanism, apoptosis, energy metabolism and osmoregulation in hybrid oysters under low salinity stress. PMID:28182701

  3. Transcriptomic analysis of Crassostrea sikamea × Crassostrea angulata hybrids in response to low salinity stress.

    PubMed

    Yan, Lulu; Su, Jiaqi; Wang, Zhaoping; Yan, Xiwu; Yu, Ruihai; Ma, Peizhen; Li, Yangchun; Du, Junpeng

    2017-01-01

    Hybrid oysters often show heterosis in growth rate, weight, survival and adaptability to extremes of salinity. Oysters have also been used as model organisms to study the evolution of host-defense system. To gain comprehensive knowledge about various physiological processes in hybrid oysters under low salinity stress, we performed transcriptomic analysis of gill tissue of Crassostrea sikamea ♀ × Crassostrea angulata♂ hybrid using the deep-sequencing platform Illumina HiSeq. We exploited the high-throughput technique to delineate differentially expressed genes (DEGs) in oysters maintained in hypotonic conditions. A total of 199,391 high quality unigenes, with average length of 644 bp, were generated. Of these 35 and 31 genes showed up- and down-regulation, respectively. Functional categorization and pathway analysis of these DEGs revealed enrichment for immune mechanism, apoptosis, energy metabolism and osmoregulation under low salinity stress. The expression patterns of 41 DEGs in hybrids and their parental species were further analyzed by quantitative real-time PCR (qRT-PCR). This study will serve as a platform for subsequent gene expression analysis regarding environmental stress. Our findings will also provide valuable information about gene expression to better understand the immune mechanism, apoptosis, energy metabolism and osmoregulation in hybrid oysters under low salinity stress.

  4. Effects of cyanobacteria Synechocystis spp. in the host-parasite model Crassostrea gasar-Perkinsus marinus.

    PubMed

    Queiroga, Fernando Ramos; Marques-Santos, Luis Fernando; Hégaret, Hélène; Sassi, Roberto; Farias, Natanael Dantas; Santana, Lucas Nunes; da Silva, Patricia Mirella

    2017-03-27

    Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4h) and long (48h and 7days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of cyanobacteria; while neither the WCs nor the ECPs modified phagocytosis of the biological particles, zymosan and P. marinus. Our results suggest a negative effect of cyanobacteria from the Synechocystis genus on host immune cells, in contrast to a more beneficial effect on the parasite cell, which

  5. First study in cryopreserved Crassostrea angulata sperm.

    PubMed

    Riesco, Marta F; Félix, Francisca; Matias, Domitilia; Joaquim, Sandra; Suquet, Marc; Cabrita, Elsa

    2017-05-01

    Sperm cryopreservation is a widely employed technique that promotes alternative techniques to contribute to broodstock management or restoration programs for species of commercial interest, endangered species or species with an interesting genotype. The preservation of genetic material from improved stocks or from the original population is extremely important for the oyster aquaculture industry to prevent the potential impacts of epidemic diseases and natural disasters. The Portuguese oyster, Crassostrea angulata, was the most important species commercialized by the shellfish industry. However, inadequate management of this industry and pathology occurrences resulted in a significant decrease in natural populations. For this reason, in this work a successful sperm cryopreservation protocol for this important species has been developed for the first time. Different internal cryoprotectants (DMSO, ethylene glycol, polyethylene glycol and methanol) at several concentrations (5, 10, 20%), containers (straws vs cryovials) and freezing rates (slow and fast rates) were tested. Cryoprotectant toxicity tests corroborated that this assay did not take into account the following steps of cryopreservation protocol as sperm agglutination. A fast freezing rate of cells diluted in10% DMSO and the use of straws as containers were the best cryopreservation conditions for Portuguese oyster sperm. Finally, fertilization assays confirmed the efficiency of the cryopreservation protocol in oyster sperm. These results demonstrated that different susceptibilities have been detected concerning sperm cryopreservation depending on oyster species or genetic material composition. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Thalassotalea crassostreae sp. nov., isolated from Pacific oyster.

    PubMed

    Choi, Sungmi; Kim, Eunji; Shin, Su-Kyoung; Yi, Hana

    2017-07-01

    A Gram-staining-negative, aerobic, rod-shaped bacterial strain, designated LPB0090T, was isolated from the Pacific oyster, Crassostreagigas, collected from the Yeongheung Island, Korea (37° 15' 16.1″ N; 126° 29' 46.5″ E). The complete genome sequence of LPB0090T (accession number CP017689) was 3 861 670 bp long with a DNA G+C content of 38.8 mol%. The genome included 3245 protein-coding genes and six copies of rRNA operons. On the basis of the results of 16S rRNA gene sequence analysis, LPB0090T was found to form an independent phyletic line within the genus Thalassotalea, with 94.7-96.0 % sequence similarities to the previously known species of the genus. The isoprenoid quinone (Q-8) and major fatty acids (C16 : 0, C17 : 1 ω8c, and C16 : 1 ω7c and/or C16 : 1 ω6c) of the isolate were similar to those of the other members of the genus Thalassotalea. A number of phenotypic features, however, distinguished LPB0090T from its closest neighbour Thalassotalea ponticola as well as other species of the genus Thalassotalea. On the basis of the phylogenetic, genomic and phenotypic data presented in this study, the strain was classified as representing a novel species of the genus Thalassotalea. Therefore, the name Thalassotalea crassostreae sp. nov. is proposed for the isolate. The type strain is LPB0090T (=KACC 18695T=JCM 31189T).

  7. Functional characterisation of phagocytes in the Pacific oyster Crassostrea gigas

    PubMed Central

    Jiang, Shuai; Jia, Zhihao; Zhang, Tao; Wang, Lingling; Qiu, Limei; Sun, Jinsheng

    2016-01-01

    Invertebrates lack canonical adaptive immunity and mainly rely on innate immune system to fight against pathogens. The phagocytes, which could engulf and kill microbial pathogens, are likely to be of great importance and have to undertake significant roles in invertebrate immune defense. In the present study, flow cytometry combined with histological and lectin staining was employed to characterise functional features of phagocytes in the Pacific oyster Crassostrea gigas. Based on the cell size and cellular contents, haemocytes were categorised into three cell types, i.e., granulocytes, semigranulocytes and agranulocytes. Agranulocytes with smaller cell volume and lower cytoplasmic-to-nuclear ratio did not show phagocytic activity, while semigranulocytes and agranulocytes exhibited larger cell volume, higher cytoplasmic-to-nuclear ratio and phagocytic activity. In addition, granulocytes with higher side scatter (SSC) exhibited higher phagocytic activity than that of semigranulocytes. When β-integrin and lectin-like receptors were blocked by RGD tripeptide and carbohydrates, respectively, the phagocytic activity of both granulocytes and semigranulocytes was significantly inhibited, indicating that β-integrin and certain lectin-like receptors were involved in phagocytosis towards microbes. Moreover, lipopolysaccharide but not peptidylglycan could enhance phagocytic activity of granulocytes and semigranulocytes towards Vibrio splendidus and Staphylococcus aureus. Lectin staining analysis revealed that Lycopersicon esculentum lectin (LEL), binding the epitope polylactosamine, was highly distributed on the extracellular cell surface of phagocytes, and could be utilized as a potential molecular marker to differentiate phagocytes from non-phagocytic haemocytes. The results, collectively, provide knowledge on the functional characters of oyster phagocytes, which would contribute to deep investigation of cell typing and cellular immunity in bivalves. PMID:27994957

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  10. Changes in the composition and diversity of the bacterial microbiota associated with oysters (Crassostrea corteziensis, Crassostrea gigas and Crassostrea sikamea) during commercial production.

    PubMed

    Trabal Fernández, Natalia; Mazón-Suástegui, José M; Vázquez-Juárez, Ricardo; Ascencio-Valle, Felipe; Romero, Jaime

    2014-04-01

    The resident microbiota of three oyster species (Crassostrea corteziensis, Crassostrea gigas and Crassostrea sikamea) was characterised using a high-throughput sequencing approach (pyrosequencing) that was based on the V3-V5 regions of the 16S rRNA gene. We analysed the changes in the bacterial community beginning with the postlarvae produced in a hatchery, which were later planted at two grow-out cultivation sites until they reached the adult stage. DNA samples from the oysters were amplified, and 31 008 sequences belonging to 13 phyla (including Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes) and 243 genera were generated. Considering all life stages, Proteobacteria was the most abundant phylum, but it showed variations at the genus level between the postlarvae and the adult oysters. Bacteroidetes was the second most common phylum, but it was found in higher abundance in the postlarvae than in adults. The relative abundance showed that the microbiota that was associated with the postlarvae and adults differed substantially, and higher diversity and richness were evident in the postlarvae in comparison with adults of the same species. The site of rearing influenced the bacterial community composition of C. corteziensis and C. sikamea adults. The bacterial groups that were found in these oysters were complex and metabolically versatile, making it difficult to understand the host-bacteria symbiotic relationships; therefore, the physiological and ecological significances of the resident microbiota remain uncertain.

  11. Comparative Analysis of the Pattern of Population Genetic Diversity in Three Indo-West Pacific Rhizophora Mangrove Species

    PubMed Central

    Yan, Yu-Bin; Duke, Norm C.; Sun, Mei

    2016-01-01

    Rhizophora species are the most widely distributed mangrove trees in the Indo-West Pacific (IWP) region. Comparative studies of these species with shared life history traits can help identify evolutionary factors that have played most important roles in determining genetic diversity within and between populations in ocean-current dispersed mangrove tree species. We sampled 935 individuals from 54 natural populations for genotyping with 13 microsatellite markers to investigate the level of genetic variation, population structure, and gene flow on a broad geographic scale in Rhizophora apiculata, Rhizophora mucronata, and Rhizophora stylosa across the IWP region. In contrast to the pattern expected of long-lived woody plants with predominant wind-pollination, water-dispersed seeds and wide geographic range, genetic variation within populations was generally low in all the three species, especially in those peripheral populations from geographic range limits. Although the large water-buoyant propagules of Rhizophora have capacity for long distance dispersal, such events might be rare in reality, as reflected by the low level of gene flow and high genetic differentiation between most of population pairs within each species. Phylogeographic separation of Australian and Pacific island populations from SE Asian lineages previously revealed with DNA sequence data was still detectable in R. apiculata based on genetic distances, but this pattern of disjunction was not always evident in R. mucronata and R. stylosa, suggesting that fast-evolving molecular markers could be more suitable for detecting contemporary genetic structure but not deep evolutionary divergence caused by historical vicariance. Given that mangrove species generally have small effective population sizes, we conclude that genetic drift coupled with limited gene flow have played a dominant role in producing the current pattern of population genetic diversity in the IWP Rhizophora species, overshadowing the

  12. 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

  13. Comparative Analysis of the Pattern of Population Genetic Diversity in Three Indo-West Pacific Rhizophora Mangrove Species.

    PubMed

    Yan, Yu-Bin; Duke, Norm C; Sun, Mei

    2016-01-01

    Rhizophora species are the most widely distributed mangrove trees in the Indo-West Pacific (IWP) region. Comparative studies of these species with shared life history traits can help identify evolutionary factors that have played most important roles in determining genetic diversity within and between populations in ocean-current dispersed mangrove tree species. We sampled 935 individuals from 54 natural populations for genotyping with 13 microsatellite markers to investigate the level of genetic variation, population structure, and gene flow on a broad geographic scale in Rhizophora apiculata, Rhizophora mucronata, and Rhizophora stylosa across the IWP region. In contrast to the pattern expected of long-lived woody plants with predominant wind-pollination, water-dispersed seeds and wide geographic range, genetic variation within populations was generally low in all the three species, especially in those peripheral populations from geographic range limits. Although the large water-buoyant propagules of Rhizophora have capacity for long distance dispersal, such events might be rare in reality, as reflected by the low level of gene flow and high genetic differentiation between most of population pairs within each species. Phylogeographic separation of Australian and Pacific island populations from SE Asian lineages previously revealed with DNA sequence data was still detectable in R. apiculata based on genetic distances, but this pattern of disjunction was not always evident in R. mucronata and R. stylosa, suggesting that fast-evolving molecular markers could be more suitable for detecting contemporary genetic structure but not deep evolutionary divergence caused by historical vicariance. Given that mangrove species generally have small effective population sizes, we conclude that genetic drift coupled with limited gene flow have played a dominant role in producing the current pattern of population genetic diversity in the IWP Rhizophora species, overshadowing the

  14. Growth of a mangrove (Rhizophora apiculata) seedlings as influenced by GA3, light and salinity.

    PubMed

    Kathiresan, K; Rajendran, N

    2002-06-01

    The growth performance of Rhizophora apiculata Blume (mangrove) seedlings in the presence and absence of exogenous gibberellic acid (GA3) under different combinations of salinity and light was analyzed. Root and shoot growth responses of 75-day old seedlings in liquid-culture, were measured. It was concluded that light exhibited a significant inhibitory effect on all the growth parameters-number of primary roots, primary root length, shoot elongation, number of leaves, total leaf area; and, the GA3 treatment singly or in combinations with light, showed a significant influence on the total leaf area and primary root length.

  15. Dosimetric evaluation of Rhizophora spp. binderless particleboard phantom for diagnostic X-ray energy

    NASA Astrophysics Data System (ADS)

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

    2017-07-01

    This research aims to evaluate the suitability of using binderless particleboard made from Rhizophora spp. mangrove wood as a dosimetric phantom for X-ray in the diagnostic energy regions. Comparative measurements of percentage depth and surface doses in Rhizophora spp. binderless particleboard phantom and similarly shaped Perspex and water phantoms were performed. Measurements were conducted in the diagnostic X-ray energy range of 50 kVp to 90 kVp. Results showed that the binderless particleboard phantom can be used for dosimetric measurements. For the X-ray beam at 90 kVp, the binderless particleboard and water phantom showed data agreement of 1.6%, 2.7%, and 4.3% at depths of 1, 2, and 4 cm, respectively, whereas the measurements in water and Perspex were 1.8%, 2.7%, and 4.4%. The surface dose differences were due to difference in the backscattering material. The doses measured at the surface were within 0.4% for binderless particleboard and water and within 0.9% for Perspex and water.

  16. 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.

  17. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Photosynthetic capacity and intrinsic water-use efficiency of Rhizophora mangle at its southernmost western Atlantic range

    Treesearch

    M.L.G. Soares; M.M.P. Tognella; E. Cuevas; E. Medina

    2015-01-01

    The southernmost presence of Rhizophora mangle in the western Atlantic coast occurs in coastal wetlands between 27 and 28ºS in the State of Santa Catarina, Brazil. We selected mangrove communities at the estuary of Rio Tavares, Florianopolis, and Sonho Beach, Palhosa, for measurement of photosynthetic performance and intrinsic water use efficiency of R. mangle and...

  19. 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

  20. SNP Mining in Crassostrea gigas EST Data: Transferability to Four Other Crassostrea Species, Phylogenetic Inferences and Outlier SNPs under Selection

    PubMed Central

    Zhong, Xiaoxiao; Li, Qi; Yu, Hong; Kong, Lingfeng

    2014-01-01

    Oysters, with high levels of phenotypic plasticity and wide geographic distribution, are a challenging group for taxonomists and phylogenetics. Our study is intended to generate new EST-SNP markers and to evaluate their potential for cross-species utilization in phylogenetic study of the genus Crassostrea. In the study, 57 novel SNPs were developed from an EST database of C. gigas by the HRM (high-resolution melting) method. Transferability of 377 SNPs developed for C. gigas was examined on four other Crassostrea species: C. sikamea, C. angulata, C. hongkongensis and C. ariakensis. Among the 377 primer pairs tested, 311 (82.5%) primers showed amplification in C. sikamea, 353 (93.6%) in C. angulata, 254 (67.4%) in C. hongkongensis and 253 (67.1%) in C. ariakensis. A total of 214 SNPs were found to be transferable to all four species. Phylogenetic analyses showed that C. hongkongensis was a sister species of C. ariakensis and that this clade was sister to the clade containing C. sikamea, C. angulata and C. gigas. Within this clade, C. gigas and C. angulata had the closest relationship, with C. sikamea being the sister group. In addition, we detected eight SNPs as potentially being under selection by two outlier tests (fdist and hierarchical methods). The SNPs studied here should be useful for genetic diversity, comparative mapping and phylogenetic studies across species in Crassostrea and the candidate outlier SNPs are worth exploring in more detail regarding association genetics and functional studies. PMID:25238392

  1. 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

  2. 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.

  3. Three new highly-oxygenated metabolites from the endophytic fungus Cytospora rhizophorae A761.

    PubMed

    Liu, Hong-Xin; Tan, Hai-Bo; Liu, Yuan; Chen, Yu-Chan; Li, Sai-Ni; Sun, Zhang-Hua; Li, Hao-Hua; Qiu, Sheng-Xiang; Zhang, Wei-Min

    2017-03-01

    Cytosporaphenones A-C, one new polyhydric benzophenone and two new naphtopyrone derivatives, along with eight known ones, were isolated from Cytospora rhizophorae, an endophytic fungus from Morinda officinalis. Their structures were fully characterized by means of detailed spectroscopic analysis and X-ray single crystal diffraction. To our knowledge, the three new compounds were the most highly oxygenated metabolites of their families discovered in nature. Moreover, all of the compounds were evaluated for in vitro cytotoxic activities against MCF-7, NCI-H460, HepG-2 and SF-268 tumor cell lines, and the new compound 1 exhibited weak growth inhibitory activity against the tumor cell lines MCF-7 and HepG-2 with IC50 values of 70 and 60μM, respectively.

  4. Effect of tannin from Rhizophora apiculate as corrosion inhibitor for epoxy paint on mild steel

    NASA Astrophysics Data System (ADS)

    Idora, M. S. Noor; Quen, L. K.; Kang, H. S.

    2017-09-01

    There is a great concern to protect the steel surfaces from corrosion phenomenon in seawater environment. Several approaches have been proposed to introduce alternative new compounds in the paint which are green sources that can reduce environmental risks. The aim of this investigation was to enhance the protection properties of epoxy paint by providing an anticorrosive inhibitor for the paint. In this approach, the abilities of mangrove tannins, extracted from Rhizophora apiculata bark were studied. The inhibitive properties of mangrove tannins were evaluated by weight loss measurement, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Results shows the addition of mangrove tannin in the coating boosted the anticorrosive properties of the paint and represents valuable environmentally friendly of inhibitor.

  5. Polyphenol and phytosterol composition in an antibacterial extract from Rhizophora mangle L. bark.

    PubMed

    Sánchez Perera, Luz María; Varcalcel, Lino; Escobar, Arturo; Noa, Mario

    2007-01-01

    Rhizophora mangle L. bark aqueous extract has antimicrobial, wound healing and antiulcerogenic properties. These properties could be associated with its chemical composition. To test this hypothesis, gravimetric, colorimetric, gas chromatography techniques were used to determine the preliminary chemical composition of this extract. Sephadex LH-20 Exclusion Chromatography was used by the fractionation of total extract and fractionation of low molecular weight polyphenols by liquid/liquid extraction. High Performance Liquid Chromatography was used to perform the composition in this low molecular weigh polyphenols fraction. The extract presented polyphenolic structures (54.78%) and other structural components (45.22%). Polymeric tannins were the major polyphenolic component (80%) and 20% were hydrolysable tannins. Epicatechin, catechin, chlorogenic acid, gallic acid and ellagic acid were monomeric structures determined in this extract. Phytosterols (0.0285%): stigmasterol, beta-sitosterol and campesterol were also present.

  6. 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.

  7. ABCB1 and ABCC1-like transporters in immune system cells from sea urchins Echinometra lucunter and Echinus esculentus and oysters Crassostrea gasar and Crassostrea gigas.

    PubMed

    Marques-Santos, Luis Fernando; Hégaret, Hélène; Lima-Santos, Leonardo; Queiroga, Fernando Ramos; da Silva, Patricia Mirella

    2017-09-05

    ABC transporters activity and expression have been associated with the multixenobiotic resistance phenotype (MXR). The activity of these proteins leads to a reduction in the intracellular concentration of several xenobiotics, thus reducing their toxicity. However, little attention has been given to the expression of ABC transporters in marine invertebrates and few studies have investigated their role in immune system cells of sea urchins and shellfish bivalves. The aim of the present study was to investigate the activity of the ABC transporters ABCB1 and ABCC1 in immune system cells of sea urchins (coelomocytes) and oysters (hemocytes) from different climatic regions (Brazil and France). Sea urchins and oysters were collected at Paraíba coast; Brazil (Echinometra lucunter and Crassostrea gasar) and Rade of Brest; France (Echinus esculentus and Crassostrea gigas). Coelomocytes and hemocytes were stained with the ABC transporter substrate calcein-AM and dye accumulation analyzed under flow cytometry. Reversin 205 (ABCB1 transporter blocker) and MK571 (ABCC1 transporter blocker) were used as pharmacological tools to investigate ABC transporter activity. A different pattern of calcein accumulation was observed in coelomocytes: phagocytes > colorless spherulocytes > vibrate cells > red spherulocytes. The treatment with MK571 increased calcein fluorescence levels in coelomocytes from both species. However, reversin 205 treatment was not able to increase calcein fluorescence in E. esculentus coelomocytes. These data suggest that ABCC1-like transporter activity is present in both sea urchin species, but ABCB1-like transporter activity might only be present in E. lucunter coelomocytes. The activity of ABCC1-like transporter was observed in all cell types from both bivalve species. However, reversin 205 only increased calcein accumulation in hyalinocytes of the oyster C. gasar, suggesting the absence of ABCB1-like transporter activity in all other cell types

  8. 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.

  9. 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

  10. 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.

  11. Impact of atrazine on aneuploidy in pacific oysters, Crassostrea gigas.

    PubMed

    Bouilly, Karine; Leitão, Alexandra; McCombie, Helen; Lapègue, Sylvie

    2003-01-01

    Aneuploidy has previously been described and studied in the Pacific oyster, Crassostrea gigas, and has been shown to be negatively correlated with growth. The present study investigated the effect of atrazine on the level of aneuploidy in this species. Crassostrea gigas adults and juveniles were subjected to different concentrations of atrazine representing a peak value found in a polluted environment (46.5 nM) and a value 10 times higher (465 nM). Although atrazine did not show any effect on the oyster mortality, significant differences in aneuploidy level were observed between the different treatments (9% for the control, 16% for 46.5 nM and 20% for 465 nM atrazine). Moreover, the same levels of aneuploidy were observed at adult and juvenile stages. This is the first reported evidence for an environmental effect on aneuploidy in C. gigas. These results will be useful for the oyster aquaculture industry and management of resources. The lowest atrazine level in the current study represents realistic potential exposure, and the results suggest that studies should be made on other aquatic species at risk of exposure to atrazine in the wild. This widely used compound may be an important factor causing damage to genetic material.

  12. 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.

  13. The reproductive cycle of the oyster Crassostrea gasar.

    PubMed

    Gomes, C H A M; Silva, F C; Lopes, G R; Melo, C M R

    2014-11-01

    The purpose of this study was to analyze the reproductive cycle of the oyster Crassostrea gasar (= C. brasiliana) in the field and the laboratory. The reproductive cycle of the animals was evaluated in the field at Sambaqui Beach, Florianópolis, SC (27° 29'18″ S and 48° 32'12″ W) from May 2008 through November 2009. In July, the animals were in the resting stage. The early growth stage began in August and was followed by the late growth stage in October. In November and December, the oysters began to enter the mature stage. Females in spawning condition were predominant during these months. The stages of the reproductive cycle were positively associated with temperature (r=0.77, P<0.01) and negatively associated with salinity (r=-0.56, P=0.042). These findings demonstrated that increased temperature and reduced salinity influence the reproductive development of Crassostrea gasar. The condition index (CI) of the animals was also associated with the seawater temperature. The highest values of the condition index were observed during the months when the temperature of the seawater was gradually increasing. A laboratory experiment was performed to test the effect of salinity on the reproductive cycle of the oysters. The experiment was conducted in standardized tanks. The animals were conditioned using two salinities (24‰ and 34‰). The salinity regime influenced the development of the gonadal tissue of the oysters. A salinity of 24‰ produced greater reproductive development.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  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. Root biomechanics in Rhizophora mangle: anatomy, morphology and ecology of mangrove's flying buttresses.

    PubMed

    Méndez-Alonzo, Rodrigo; Moctezuma, Coral; Ordoñez, Víctor R; Angeles, Guillermo; Martínez, Armando J; López-Portillo, Jorge

    2015-04-01

    Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is stabilized by rhizophores resembling flying

  20. Root biomechanics in Rhizophora mangle: anatomy, morphology and ecology of mangrove’s flying buttresses

    PubMed Central

    Méndez-Alonzo, Rodrigo; Moctezuma, Coral; Ordoñez, Víctor R.; Angeles, Guillermo; Martínez, Armando J.; López-Portillo, Jorge

    2015-01-01

    Background and Aims Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. Methods The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. Key Results Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. Conclusions In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is

  1. Cholinesterase inhibitory effects of Rhizophora lamarckii, Avicennia officinalis, Sesuvium portulacastrum and Suaeda monica: Mangroves inhabiting an Indian coastal area (Vellar Estuary).

    PubMed

    Suganthy, Natarajan; Pandian, Shanmugiahthevar Karutha; Devi, Kasi Pandima

    2009-06-01

    Alzheimer's disease is a progressive neurodegenerative illness accounting for approximately 50% of all types of dementia in elderly people. The only symptomatic treatment proven effective to date is the use of cholinesterase inhibitors to augment surviving cholinergic activity. The purpose of this study is to investigate cholinesterase inhibitory activity of mangroves as an alternative medicine for the treatment of Alzheimer's disease. About nine mangrove plants, which were used as folk medicine in tropical countries, were collected from Parangipettai, Vellar estuary, Tamilnadu, India. Nile Tilapia muscle homogenate was used as source of enzyme. Inhibitory effect of methanolic leaf extract was assessed under in vitro condition by incubating various concentration of the extract with total cholinesterase and butyryl cholinesterase and assessing their residual activities by Ellman's colorimetric method. The results showed that of the nine plants screened Rhizophora lamarckii, Suaeda monica, Avicennia officinalis and Sesuvium portulacastrum showed 50% inhibitory activity to both TChE and BChE at concentrations less than 2 mg/mL when compared to other plant extracts, which was comparable to the standard drug Donepezil. Phytochemical analysis showed the presence of alkaloids in high concentration which might be correlated to its cholinesterase inhibitory activity.

  2. [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.

  3. Shell hardness and compressive strength of the Eastern oyster, Crassostrea virginica, and the Asian oyster, Crassostrea ariakensis.

    PubMed

    Lombardi, Sara A; Chon, Grace D; Lee, James Jin-Wu; Lane, Hillary A; Paynter, Kennedy T

    2013-12-01

    The valves of oysters act as a physical barrier between tissues and the external environment, thereby protecting the oyster from environmental stress and predation. To better understand differences in shell properties and predation susceptibilities of two physiologically and morphologically similar oysters, Crassostrea virginica and Crassostrea ariakensis, we quantified and compared two mechanical properties of shells: hardness (resistance to irreversible deformation; GPa) and compressive strength (force necessary to produce a crack; N). We found no differences in the hardness values between foliated layers (innermost and outermost foliated layers), age class (C. virginica: 1, 4, 6, 9 years; C. ariakensis: 4, 6 years), or species. This suggests that the foliated layers have similar properties and are likely composed of the same material. The compressive force required to break wet and dry shells was also not different. However, the shells of both six- and nine-year-old C. virginica withstood higher compressive force than C. virginica shells aged either one or four, and the shells of C. ariakensis at both ages studied (4- and 6-years-old). Differences in ability to withstand compressive force are likely explained by differences in thickness and density between age classes and species. Further, we compared the compressive strength of differing ages of these two species to the crushing force of common oyster predators in the Chesapeake Bay. By studying the physical properties of shells, this work may contribute to a better understanding of the mechanical defenses of oysters as well as of their predation vulnerabilities.

  4. 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.

  5. 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.

  6. 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.

  7. Semi-viviparous embryo development and dehydrin expression in the mangrove Rhizophora mucronata Lam.

    PubMed Central

    Ismail, Flora AbdulRahman; Nitsch, Lisette M. C.; Wolters-Arts, Mieke M. C.; Derksen, Jan W. M.

    2010-01-01

    Rhizophora mucronata Lam. is a tropical mangrove with semi-viviparous (cotyledon body protrusion before shedding), non-quiescent and non-desiccating (recalcitrant) seeds. As recalcitrance has been thought to relate to the absence of desiccation-related proteins such as dehydrins, we for the first time systematically described and classified embryogenesis in R. mucronata and assessed the presence of dehydrin-like proteins. Embryogenesis largely follows the classic pattern till stage eight, the torpedo stage, with the formation of a cotyledonary body. Ovule and embryo express radical adaptations to semi-vivipary in the saline environment: (1) A large, highly vacuolated and persistent endosperm without noticeable food reserves that envelopes the developing embryo. (2) Absence of vascular tissue connections between embryo and maternal tissue, but, instead, transfer layers in between endosperm and integument and endosperm and embryo. Dehydrin-like proteins (55–65 kDa) were detected by the Western analysis, in the ovules till stage 10 when the integuments are dehisced. An additional 50 kDa band was detected at stages 6–8. Together these results suggest a continuous flow of water with nutrients from the integument via the endosperm to the embryo, circumventing the vascular route and probably suppressing the initially induced dehydrin expression. PMID:20084524

  8. Ecophysiological responses of young mangrove species Rhizophora apiculata (Blume) to different chromium contaminated environments.

    PubMed

    Nguyen, Kim Linh; Nguyen, Hoang Anh; Richter, Otto; Pham, Minh Thinh; Nguyen, Van Phuoc

    2017-01-01

    Many mangrove forests have suffered from the contaminated environments near industrial areas. This study addresses the question how these environments influence the renewal of mangrove forests. To this end ecophysiological responses of the young mangrove species Rhizophora apiculata (Blume) grown under combinations of the factors heavy metals (here chromium), nutrition and soil/water environment were analyzed. We tested the hypothesis that soil/water conditions and nutrient status of the soil strongly influence the toxic effect of chromium. Seedlings of R. apiculata were grown in three different soil/water environments (natural saline soil with brackish water, salt-leached soil with fresh water and salt-leached-sterilized soil with fresh water) treated with different levels of chromium and NPK fertilizer. The system was inundated twice a day as similar to natural tidal condition in the mangrove wetland in the south of Vietnam. The experiments were carried out for 6months. Growth data of root, leaf and stem, root cell number and stomata number were recorded and analyzed. Results showed that growth of R. apiculata is slower in natural saline soil/water condition. The effect of chromium and of nutrients respectively depends on the soil/water condition. Under high concentrations of chromium, NPK fertilizer amplifies the toxic effect of chromium. Stomata density increases under chromium stress and is largest under the combination of chromium and salty soil/water condition. From the data a nonlinear multivariate regression model was derived capturing the toxicity threshold of R. apiculata under different treatment combinations.

  9. [Chemical constituents in the leave of Rhizophora stylosa L and their biological activities].

    PubMed

    Yang, Xu-hong; Li, Huai-biao; Chen, Hong; Li, Ping; Ye, Bo-ping

    2008-09-01

    Ten compounds were isolated from the leaves of Rhizophora stylosa, one kind of mangrove plants distributed in the tropical and subtropical areas of the world. Their structures were identified as taraxerone (1), taraxerol (2), beta-sitosterol (3), careaborin (4), cis-careaborin (5), beta-daucosterol (6), isovanillic acid (7), protocatechuic acid (8), astilbin (9) and rutin (10), among which compound 9 and 10 were reported in this plant for the first time. Of these compounds, Compound 2 has been confirmed to have the abilities to inhibit the growth of Hela and BGC-823 with IC50 of 73.4 micromol x L(-1) and 73.3 micromol x L(-1), respectively. Compound 5 could inhibit the growth of BGC-823 and MCF-7 with IC50 of 45.9 micromol x L(-1) and 116.0 micromol x L(-1), respectively. Compound 9 and 10 were firstly reported to stimulate the proliferation of mice splenic lymphocytes markedly in a dose-dependent manner.

  10. 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.

  11. Flower morphometry of Rhizophora mangle (Rhizophoraceae): geographical variation in Mexican populations.

    PubMed

    Domínguez, C; Eguiarte, L; Núñez-Farfán, J; Dirzo, R

    1998-05-01

    We explored the patterns of intra- and interpopulation variation in flower morphology of the red mangrove, Rhizophora mangle. Twelve populations in Mexico were studied: five from the Gulf of Mexico and the Caribbean Sea, and seven from the Pacific Coast. Six metric floral attributes were measured from a sample of 1370 flowers. Significant differences among populations were found for all six attributes. Because floral attributes were all correlated, scores derived from principal factor analysis were used to describe the variation in flower morphology. Two factors explained essentially all of the variance in flower morphology. Corolla and calyx size had a strong effect on factor 1, while gynoecium size had the higher effect on factor 2. Nested analyses of variance on the scores from both factors revealed significant differences among coasts, among populations within coasts, and among plants within populations. Nonetheless, this variation cannot be explained as a result of clinal variation, as indicated by a series of regression analyses. Cluster analysis (UPGMA) showed that a population from the Pacific coast was clustered together with those of the Atlantic, and the arrangement of populations within each coast showed no evident geographical pattern. We propose that frequent events of extinction and recolonization by a few individuals, followed by selfing, may produce differentiation among populations of red mangrove.

  12. Bioinformatics approach of salt tolerance gene in mangrove plant Rhizophora stylosa

    NASA Astrophysics Data System (ADS)

    Basyuni, M.; Sumardi

    2017-01-01

    This study descibes bioinformatics approach on the analyze of the salt tolerance genes in mangrove plant, Rhizophora stylosa on DDBJ/EMBL/GenBank as well as similarity, phylogenetic, potential peptide, and subcellular localization. The DNA sequence between salt tolerance gene from R. stylosa exhibited 42-11% between themselves The target peptide value of mitochondria varied from 0.163 to 0.430, indicated it was possible to exist. These results suggested the importance of understanding the diversity and functional of properties of the different amino acids in mangrove OSC genes. To clarify the relationship among the salt-tolerant genes in R. stylosa, a phylogenetic tree was constructed. The phylogenetic tree shows that there are three clusters, first branch of Cu/Zn SOD and reverse transcriptase genes, the second branch consists of the majority genes and the last group was MAP3K alpha protein kinase only. The present study, therefore, suggested that salt tolerance genes form distinct clusters in the tree.

  13. Sewage input reduces the consumption of Rhizophora mangle propagules by crabs in a subtropical mangrove system.

    PubMed

    Boehm, Frederike Ricarda; Sandrini-Neto, Leonardo; Moens, Tom; da Cunha Lana, Paulo

    2016-12-01

    Mangrove forests are highly productive and play a major role in global carbon cycling. Their carbon accumulation can be influenced through the consumption of nutrient-poor leaves and propagules by herbivore crabs. Anthropogenic nutrient input from sewage contamination is widespread in these often naturally nutrient-limited ecosystems. We hypothesised that sewage-mediated nutrient input to mangrove stands of Paranaguá Bay (southern Brazil), would alter the nutrient sources available for crabs, e.g. through microphytobenthos increase, and that this would reflect in their feeding behaviour. We predicted that propagules of Rhizophora mangle in contaminated stands would experience lower grazing pressure from their two main local consumers (Ucides cordatus and Goniopsis cruentata). We compared herbivory rates on R. mangle propagules in sewage contaminated and uncontaminated mangrove stands. We found that herbivory rates were significantly lower in contaminated than uncontaminated forests, but this pattern could not be clearly attributed to increased nutrient availability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 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.

  15. 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.

  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. 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

  18. A feeding model of oyster larvae (Crassostrea angulata).

    PubMed

    Qiu, Tianlong; Liu, Ying; Zheng, Jimeng; Zhang, Tao; Qi, Jianfei

    2015-08-01

    There is a need to develop more efficient rearing systems for the aquaculture of economically important bivalves, such as oysters. Here, we constructed a model that describes the feeding behavior of larval Crassostrea angulata oysters and tested it in an experimental setting. Larval ingestion rate is closely correlated with larval length. Based on our model, we showed that larval swimming speed, velum diameter and the filtration coefficient, which also determine the ingestion rate, are also correlated with larval length. Our model integrates morphological, locomotory and feeding behavior parameters to establish a relation between them and so provides a mathematical way to describe variation in the feeding behavior of bivalve larvae. The results of this study could facilitate the precise management of the aquaculture of bivalve larvae, in particular the optimum prey density and feeding rate of these important organisms.

  19. 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.

  20. Photo-enhanced toxicity of two weathered Macondo crude oils to early life stages of the eastern oyster (Crassostrea virginica).

    PubMed

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

    2016-12-15

    Polycyclic aromatic hydrocarbons (PAHs) have been reported to absorb ultraviolet (UV) light, resulting in enhanced toxicity. Early developmental stages of bivalves may be particularly susceptible to photo-enhanced toxicity during oil spills. In the current study, toxicity tests were conducted with sperm and three larval ages of the eastern oyster (Crassostrea virginica) to evaluate the photo-enhanced toxicity of low-energy water-accommodated fractions (WAFs) of two weathered Macondo crude oils collected from the Deepwater Horizon incident. Larvae exposed to oil WAFs under UV-filtered light demonstrated consistently higher survival and normal development than larvae exposed to WAFs under UV light. The phototoxicity of weathered Macondo oil increased as a function of increasing UV light intensity and dose. Early developing oyster larvae were the most sensitive to photo-enhanced toxicity, whereas later shelled prodissoconch larvae were insensitive. Comparisons between two weathered crude oils demonstrated that toxicity was dependent on phototoxic PAH concentration and UV light intensity.

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

    PubMed

    Ferreira, A M; Cortesão, C; Castro, O G; Vale, C

    1990-11-01

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

  2. Measurement of mass attenuation coefficients of Eremurus-Rhizophora spp. particleboards for X-ray in the 16.63-25.30 keV energy range

    NASA Astrophysics Data System (ADS)

    Tousi, E. T.; Bauk, S.; Hashim, R.; Jaafar, M. S.; Abuarra, A.; Aldroobi, K. S. A.; Al-Jarrah, A. M.

    2014-10-01

    The roots of Eremurus spp. were used as a bio-adhesive in the fabrication of Rhizophora spp. particleboards. The mass attenuation coefficients of Eremurus-Rhizophora spp. particleboard of six samples with two different weight percentages of the Eremurus spp. root (6% and 12%) and three various Rhizophora spp. particle sizes (≤149 μm, 149-500 μm and 500-1000 μm) were determined by using X-ray fluorescence (XRF) photons in 16.63 keV and 25.30 keV of the photon energy range. The results were compared with theoretically calculated mass attenuations using the XCOM computer program for younger-age (breast 1: 75% muscle+25% fat), middle-age (breast 2: 50% muscle+50% fat), and old-age (breast 3: 25% muscle+75% fat) breasts. The results indicated that Eremurus-Rhizophora spp. particleboard is the appropriate suitable phantom in the diagnostic energy region. The mass attenuation coefficient in the low weight percentage of the bio-adhesive and the large Rhizophora spp. particle size were found very close to breast 1. Moreover the mass attenuation coefficient of the sample with high weight percentage of the bio-adhesive and small Rhizophora spp. particle size was found very close to water as a standard material phantom. In addition, the viscosity of dissolved Eremurus spp. root in water could be considerably higher than that of formaldehyde-based adhesives, which affects on some properties such as high strength and high binding.

  3. 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.

  4. 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.

  5. Parasites of the pleasure oyster Crassostrea corteziensis cultured in Nayarit, Mexico.

    PubMed

    Cáceres-Martínez, Jorge; Vasquez-Yeomans, Rebeca; Padilla-Lardizábal, Gloria

    2010-09-01

    The pleasure oyster Crassostrea corteziensis is collected and cultured in Nayarit on the Pacific coast of Mexico, and the improvement and promotion of its culture are seen as a possible source for the economic development of coastal populations. However, information about the parasite fauna of the pleasure oyster is almost completely lacking. A histopathological survey carried out in two estuaries, Boca del Camichín and Pozo Chino, revealed the presence of hypertrophied gametes, rickettsiales-like prokaryotes (RLPs), the protozoan Perkinsus marinus, a protozoan Nematopsis sp., Ancistrocoma-like ciliates (ALCs), Sphenophrya-like ciliates, a turbellarian Urastoma sp., and encysted crustaceans. In general, prevalence and intensity of parasites were similar in both localities except that ALCs and encysted crustaceans were more prevalent in Pozo Chino than in Boca del Camichín. Perkinsus marinus and RLPs seem to represent a more significant risk for the health of pleasure oysters than do the other parasites, and surveillance and control of these parasites are needed for the development of pleasure oyster culture.

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

    DOE PAGES

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

    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

  7. 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.

  8. Acanthoparyphium sp. and other metazoan symbionts of the American oyster, Crassostrea virginica, from South Texas.

    PubMed

    Fredensborg, B L; Ramirez, J J; Partida, L

    2013-12-01

    In this study, we investigated oysters, Crassostrea virginica , from Laguna Madre in South Texas, where a 45-yr old study recorded metacercarial infections of the echinostomatid trematode, Acanthoparyphium spinulosum , an Asian relative of which, Acanthoparyphium tyosenense, has been associated with human infections via the ingestion of raw mollusks. In an effort to examine the base-line infection parameters of Acanthoparyphium sp. in oysters, we examined the effect of distance from the shoreline, which is the habitat of the first intermediate host snail, Cerithidea pliculosa, as well as temporal changes in oyster infection levels, by conducting quarterly collections of oysters during a year. We found that almost all oysters (prevalence = 97.8-100%) were infected regardless of distance to the shoreline and season. However, the abundance of metacercariae was significantly higher close to the shoreline, while no significant temporal changes could be detected. In addition to the echinostomatid, we found a high abundance of the metacestode Tylocephalum sp. and the presence of 4 other metazoan parasites. None of the infections seemed to incur significant tissue damage to the oysters. Our study shows that at least locally, recreational harvesters of oysters may be exposed to Acanthoparyphium sp. Future studies should examine oysters from snail host habitats in the Gulf of Mexico, and the potential zoonotic risk of Acanthoparyphium sp. should be evaluated using experimental infections of animal models.

  9. Fluoranthene-induced historical alterations in oysters, Crassostrea virginica: Seasonal field and laboratory studies

    SciTech Connect

    Weinstein, J.E.

    1995-12-31

    Stress-related histological parameters (digestive epithelial thickness, gonadal area, incidences of heiminth parasites and hemocytic infiltration, and parasite intensity) were monitored seasonally in the visceral mass of oysters, Crassostrea virginica, collected from an undeveloped site (Clambank Creek, North Inlet estuary, SC) and two urbanized, fluoranthene-contaminated sites (Parsonage Creek and Marina pipe, Murrells Inlet estuary, SC). Reduced mean epithelial thickness and an elevated incidence of hemocytic infiltration was occasionally observed in the Murrells Inlet oysters. Correlation analysis revealed that the seasonal profile of mean epithelial thickness in the Parsonage Creek oysters was related to that of their body burdens of fluoranthene and six other polycyclic aromatic hydrocarbons. Oysters exposed to fluoranthene in the laboratory also exhibited a reduction in their mean digestive epithelial thickness, and this response was dependent upon the interaction between fluoranthene body burden and exposure time. These results suggest that thinning of the digestive epithelium is a useful histological indicator of fluoranthene-induced stress, and demonstrate the utility of seasonally monitoring several stress-related histological parameters in conjunction with contaminant body burdens.

  10. 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

  11. Acetylcholinesterase and metallothionein in oysters (Crassostrea corteziensis) from a subtropical Mexican Pacific estuary.

    PubMed

    Bernal-Hernández, Y Y; Medina-Díaz, I M; Robledo-Marenco, M L; Velázquez-Fernández, J B; Girón-Pérez, M I; Ortega-Cervantes, L; Maldonado-Vázquez, W A; Rojas-García, A E

    2010-04-01

    Substantial efforts have been devoted to developing and applying biomarkers for ecological risk assessment. Bivalve mollusks, such as mussels and oysters, are commonly used in environmental monitoring programs because of their wide geographical distribution, great sensitivity to environmental pollutants, and ability to accumulate anthropogenically derived chemicals at a high rate. Acetylcholinesterase (AChE) activity and metallothionein (MT's) content are representative specific biomarkers that indicate the presence of anticholinesterasic compounds (like organophosphorus and carbamate pesticides) and metals, respectively. The aim of this study was to evaluate AChE activity and MT's content in Crassostrea corteziensis from Boca de Camichín estuary. The results obtained here showed that AChE activity was 65% lower in oysters from Boca de Camichín than in control organisms. In contrast, MT's content in collected organisms was not statistically different from that in control organisms. AChE activity and MT's content in oysters could be used as early biomarkers of effects and exposure to pesticides and heavy metals, respectively, in aquatic environments.

  12. 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

  13. Red mangrove (Rhizophora mangle) reproduction and seedling colonization after Hurricane Charley: Comparisons of Charlotte Harbor and Tampa Bay

    USGS Publications Warehouse

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

    2006-01-01

    Reproductive aspects of life history are known to be important in recovery following disturbance in many plant species although this has not been well studied in mangroves. Hurricane Charley devastated large areas of mangroves in Charlotte Harbor, Florida, in August 2004. We surveyed 6 forests in Charlotte Harbor (2002, 2003, and 2005) and 16 in Tampa Bay, Florida (2001, 2002, 2003, and 2005) for total numbers of reproducing trees and trees heterozygotic for albinism that produce both normal and albino propagules. Tree size (estimated height and diameter at breast height) was also recorded for sentinel heterozygotic trees. Total number of reproducing trees km-1 was used as an index of reproductive output of the population, and deviation from the 3:1 (normal:albino propagules) ratio on heterozygotic trees expected with 100% selfing was used to estimate outcrossing. Numbers of Rhizophora mangle reproducing trees km-1 of shoreline in Charlotte Harbor were reduced by an order of magnitude following Hurricane Charley, while numbers of reproducing trees in Tampa Bay were similar to those of previous years. Reduced reproduction in Charlotte Harbor was accompanied by fewer new recruits in plots on Sanibel and Captiva Islands. Numbers of new recruits after the storm also tended to be fewer in plots where canopy loss was greater. More new recruits occurred in sites that had higher densities of pre-storm Rhizophora seedlings and greater relative dominance by Rhizophora. Outcrossing of sentinel trees was 2.5 times greater in Charlotte Harbor (mean site-1 = 33.6 ?? 6.7%; with 17% of forest sites completely selfing) than in Tampa Bay (mean site-1 = 13.4 ?? 4.7%; with 40% of sites completely selfing), although the implications for seedling recruitment of this difference are not known. ?? 2006 Estuarine Research Federation.

  14. Isotopic and molecular distributions of biochemicals from fresh and buried Rhizophora mangle leaves†

    PubMed Central

    Smallwood, Barbara J; Wooller, Matthew J; Jacobson, Myrna E; Fogel, Marilyn L

    2003-01-01

    Rhizophora mangle L. (red mangrove) is the dominant species of mangrove in the Americas. At Twin Cays, Belize (BZ) red mangroves are present in a variety of stand structures (tall >5 m in height, transition ~2–4 m and dwarf ~1–1.5 m). These height differences are coupled with very different stable carbon and nitrogen isotopic values[1] (mean tall δ13C = -28.3‰, δ15N = 0‰; mean tall δ13C = -25.3‰, δ15N = -10‰). To determine the utility of using these distinct isotopic compositions as 'biomarkers' for paleoenvironmental reconstruction of mangrove ecosystems and nutrient availability, we investigated the distribution and isotopic (δ13C and δ15N) composition of different biochemical fractions (water soluble compounds, free lipids, acid hydrolysable compounds, individual amino acids, and the residual un-extractable compounds) in fresh and preserved red mangrove leaves from dwarf and tall trees. The distribution of biochemicals are similar in dwarf and tall red mangrove leaves, suggesting that, regardless of stand structure, red mangroves use nutrients for biosynthesis and metabolism in a similar manner. However, the δ13C and δ15N of the bulk leaf, the biochemical fractions, and seven amino acids can be used to distinguish dwarf and tall trees at Twin Cays, BZ. The data support the theory that the fractionation of carbon and nitrogen occurs prior to or during uptake in dwarf and tall red mangrove trees. Stable carbon and nitrogen isotopes could, therefore, be powerful tools for predicting levels of nutrient limitation at Twin Cays. The δ13C and δ15N of biochemical fractions within preserved leaves, reflect sedimentary cycling and nitrogen immobilization. The δ15N of the immobilized fraction reveals the overlying stand structure at the time of leaf deposition. The isotopic composition of preserved mangrove leaves could yield significant information about changes in ecosystem dynamics, nutrient limitation and past stand structure in mangrove

  15. Postglacial expansion pathways of red mangrove, Rhizophora mangle, in the Caribbean Basin and Florida.

    PubMed

    Kennedy, John Paul; Pil, Maria W; Proffitt, C Edward; Boeger, Walter A; Stanford, Alice M; Devlin, Donna J

    2016-02-01

    The Last Glacial Maximum (LGM) was a period of massive range contraction. Post-LGM, water-dispersed coastal species, including the red mangrove (Rhizophora mangle), expanded poleward as propagules were transported by ocean currents. We assessed postglacial marine expansion pathways for R. mangle within the Caribbean Basin and Florida. Six microsatellite loci were used to genotype 237 individuals from nine R. mangle populations in the Caribbean, Florida, and Northwest Africa. We evaluated genetic variation, population structure, gene flow along alternative post-LGM expansion pathways to Florida, and potential long-distance dispersal (LDD) from West Africa to Caribbean islands. These R. mangle populations had substantial genetic structure (FST = 0.37, P < 0.0001) with three discrete population clusters (Caribbean mainland, Caribbean islands, and Florida). Genetic connectivity along the mainland pathway (Caribbean mainland to Florida) vs. limited gene dispersal along the Antilles Island pathway (Caribbean islands to Florida) supported Florida recolonization from Caribbean mainland sources. Genetic similarity of Northwest Africa and two Caribbean islands provided evidence for trans-Atlantic LDD. We did not find a pattern of decreasing genetic diversity with latitude. We outline a complex expansion history for R. mangle, with discrete pathways of recolonization for Florida and Caribbean islands. Contrary to expectation, connectivity to putative Caribbean mainland refugial populations via ocean currents, and not latitude, appears to dictate genetic diversity within Caribbean island and Florida R. mangle. These findings provide a framework for further investigation of additional water-dispersed neotropical species, and insights for management initiatives. © 2016 Botanical Society of America.

  16. 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.

  17. Two rare antioxidant and anti-inflammatory oleanenes from loop root Asiatic mangrove Rhizophora mucronata.

    PubMed

    Chakraborty, Kajal; Raola, Vamshi Krishna

    2017-03-01

    Two oleanenes, olean-18(19)-en-3β-yl-(3,6-dimethyl-3E,6Z-dienoate) and (13α)-27-frido-olean-14(15)-en-(17α)-furanyl-3β-ol representing a class of rare natural pentacyclic triterpenoids were isolated from the chloroform extract of Asiatic mangrove, Rhizophora mucronata Lam. (Family: Rhizophoraceae). The furanyl oleanene exhibited significantly greater antioxidative activities (IC50 0.73-0.76 mg/mL), than prenylated oleanene (IC50 0.84-0.96 mg/mL) (P < 0.05). No significant differences in anti-5-lipoxygenase activities of these compounds with the synthetic drug ibuprofen was discernable (IC50 0.8-0.9 mg/mL), whilst furanyl oleanene demonstrated significantly greater anti-cyclooxygenase-2 (IC50 0.84 mg/mL) and anti-5-lipoxygenase activities (IC50 0.78 mg/mL) over prenylated oleanene (IC50 > 0.90 mg/mL). These compounds exhibited lesser activity against cyclooxygenase-1 than cyclooxygenase-2 isoform, and therefore, their selectivity indices remained significantly greater (anti-cyclooxygenase-1IC50/anti-cyclooxygenase-2IC50 > 1) than the aspirin (0.02) and ibuprofen (0.44). The lipophilic and steric molecular descriptors were found to occupy a prominent role in determining the bioactivities of the compounds. These previously undescribed oleanenes might serve as potential antioxidative and anti-inflammatory lead molecules in medicinal formulations and food industries.

  18. 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

  19. Influence of a salinity gradient on the vessel characters of the mangrove species Rhizophora mucronata.

    PubMed

    Schmitz, Nele; Verheyden, Anouk; Beeckman, Hans; Kairo, James Gitundu; Koedam, Nico

    2006-12-01

    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. 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. 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. 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.

  20. 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

  1. 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.

  2. Accumulation of six metals in the mangrove crab Ucides cordatus (Crustacea: Ucididae) and its food source, the red mangrove Rhizophora mangle (Angiosperma: Rhizophoraceae).

    PubMed

    Pinheiro, Marcelo Antonio Amaro; Silva, Pablo Pena Gandara E; Duarte, Luis Felipe de Almeida; Almeida, Alaor Aparecido; Zanotto, Flavia Pinheiro

    2012-07-01

    The crab Ucides cordatus and the red mangrove Rhizophora mangle are endemic mangrove species and potential bio-accumulators of metals. This study quantified the accumulation of six metals (Cd, Cr, Cu, Hg, Mn and Pb) in different organs (claw muscle, hepatopancreas and gills) of U. cordatus, as well as in different maturation stages of the leaves (buds, green mature, and pre-abscission senescent) of R. mangle. Samples were collected from mangrove areas in Cubatão, state of São Paulo, a heavily polluted region in Brazil. Data for metal contents in leaves were evaluated by one-way ANOVA; while for crabs a factorial ANOVA was used to investigate the effect of different tissues, animal size and the interactions between them. Means were compared by Tukey test at five percent, and the association between the metal concentrations in each crab organ, depending on the size, was evaluated by Pearson's linear correlation coefficient (r). Concentrations of Pb and Hg were undetectable for the different leaf stages and crab tissues, while Cd concentrations were undetectable in the leaf stages. In general, the highest accumulation of metals in R. mangle leaves occurred in pre-abscission senescent and green mature leaves, except for Cu, which was found in the highest concentrations in buds and green mature leaves. For the crab, Cd, Cu, Cr and Mn were present in concentrations above the detection limit, with the highest accumulation in the hepatopancreas, followed by the gills. Cu was accumulated mostly in the gills. Patterns of bioaccumulation between the crab and the mangrove tree differed for each metal, probably due to the specific requirements of each organism for essential metals. However, there was a close and direct relationship between metal accumulation in the mangrove trees and in the crabs feeding on them. Tissues of R. mangle leaves and U. cordatus proved effective for monitoring metals, acting as important bioindicators of mangrove areas contaminated by various

  3. High Salinity Relaying to Reduce Vibrio parahaemolyticus and Vibrio vulnificus in Chesapeake Bay Oysters (Crassostrea virginica).

    PubMed

    Parveen, Salina; Jahncke, Michael; Elmahdi, Sara; Crocker, Helen; Bowers, John; White, Chanelle; Gray, Stephanie; Morris, Amanda C; Brohawn, Kathy

    2017-02-01

    Cases of Vibrio infections in the United States have tripled from 1996 to 2009 and these infections are most often associated with the consumption of seafood, particularly oysters (Crassostrea virginica). Information is needed on how to reduce numbers of Vibrio parahaemolyticus and Vibrio vulnificus in bi-valve molluscan shellfish (for example, oysters). The purpose of this study was to evaluate the effectiveness of high salinity relaying or treatment in recirculating aquaculture systems (RASs) as methods to reduce the abundance of V. parahaemolyticus and V. vulnificus in oysters. For relaying field trials, oysters were collected from approved harvest waters, temperature abused outside under a tarp for 4 h, and then transferred to high (29 to 33 ppt.) and moderate (12 to 19 ppt.) salinities. For RAS treatment trial, oysters were transferred to 32 to 34 ppt. salinity at 15 °C. After 7, 14, 21, and in some instances 28 d, oysters were collected and analyzed for V. parahaemolyticus and V. vulnificus levels using multiplex real-time PCR. Initial levels of V. parahaemolyticus and V. vulnificus ranged from 3.70 to 5.64 log10 MPN/g, and were reduced by 2 to 5 logs after 21 to 28 d in high salinity water (29 to 34 ppt.). Oyster mortalities averaged 4% or less, and did not exceed 7%. Relaying of oysters to high salinity field sites or transfer to high salinity RAS tanks was more effective in reducing V. vulnificus compared with V. parahaemolyticus. These results suggest that high salinity relaying of oysters is more effective in reducing V. vulnificus than V. parahaemolyticus in the oyster species used in this study.

  4. Anatomical distribution of sterols in oysters (Crassostrea gigas).

    PubMed

    Gordon, D T; Collins, N

    1982-11-01

    Oysters (Crassostrea gigas) contain at least 8 predominant sterols as determined by gas liquid chromatography and a modified Liebermann-Burchard reaction. These sterols and the average amount found in mg/100 are: C26-sterol (22-trans-24-norcholesta-5, 22-diene-3 beta-ol), 19.1; 22-dehydrocholesterol, 15.1; cholesterol, 46.8; brassicasterol, 27.2; delta 5,7-sterols (i.e., 7-dehydrocholesterol) 22.5; 24-methylenecholesterol 29.1; 24-ethylcholesta-5,22-diene-3 beta-ol, 1.2; and 24-ethylcholesta-5-en-3 beta-ol, 12.7. The distribution of these sterols appears uniform (r2 = 0.938) between 5 major organs of the oyster. The percent body mass vs percent total sterols in these 5 organs are: mantle 44.1--41.4; visceral mass 30.3--36.7; gills 13.2--11.7; adductor muscle 8.3--3.7; and labial palps 4.2--6.5. The possible sources of these sterols are discussed.

  5. Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

    PubMed Central

    Perrigault, Mickael; Tran, Damien

    2017-01-01

    Molecular clock system constitutes the origin of biological rhythms that allow organisms to anticipate cyclic environmental changes and adapt their behavior and physiology. Components of the molecular clock are largely conserved across a broad range of species but appreciable diversity in clock structure and function is also present especially in invertebrates. The present work aimed at identify and characterize molecular clockwork components in relationship with the monitoring of valve activity behavior in the oyster Crassostrea gigas. Results provided the characterization of most of canonical clock gene including clock, bmal/cycle, period, timeless, vertebrate-type cry, rev-erb, ror as well as other members of the cryptochrome/photolyase family (plant-like cry, 6–4 photolyase). Analyses of transcriptional variations of clock candidates in oysters exposed to light / dark regime and to constant darkness led to the generation of a putative and original clockwork model in C. gigas, intermediate of described systems in vertebrates and insects. This study is the first characterization of a mollusk clockwork. It constitutes essential bases to understand interactions of the different components of the molecular clock in C. gigas as well as the global mechanisms associated to the generation and the synchronization of biological rhythms in oysters. PMID:28072861

  6. Stress-induced immune changes in the oyster Crassostrea gigas.

    PubMed

    Lacoste, Arnaud; Malham, Shelagh K; Gélébart, Florence; Cueff, Anne; Poulet, Serge A

    2002-01-01

    Information concerning the effect of stress on invertebrate immune functions are scarce. The present study investigated the consequences of a 15-min mechanical disturbance on immune parameters in oysters Crassostrea gigas. As indicated by noradrenaline and dopamine measurements, the mechanical disturbance caused a transient state of stress in oysters. The number of circulating hemocytes, the migratory and phagocytic activities and reactive oxygen species production of hemocytes were measured before, during and after application of the stressor. Results show that all immune functions were significantly downregulated during stress and a transient period of immunostimulation was observed 30-240 min after the end of the disturbance. Taken together, these results suggest that stress can exert a profound influence on oyster immune functions and they may explain why stress and the outbreak of disease are often linked in shellfish culture. Furthermore, the present study strongly suggests that checking the stress status of animals may be necessary to avoid biases when studying oyster immune responses in vivo.

  7. Study of atrazine effects on Pacific oyster, Crassostrea gigas, haemocytes.

    PubMed

    Gagnaire, B; Renault, T; Bouilly, K; Lapegue, S; Thomas-Guyon, H

    2003-01-01

    Shellfish farming is an important economic activity around the world. This activity often takes place in areas subjected to various recurring pollutions. The recrudescent use of herbicides in agriculture including atrazine implies pollutant transfer towards aquatic environment in estuarine areas. Harmful effects of such substances on animals in marine environment, particularly on cultured bivalves, are poorly documented. Bivalve molluscs such as mussels and oysters have been postulated as ideal indicator organisms because of their way of life. They filter large volumes of seawater and may therefore accumulate and concentrate contaminants within their tissues. Moreover, development of techniques allowing effect analysis of such compounds on bivalve biology may lead to the development of diagnosis tools adapted to analyze pollutant transfer towards estuarine areas. In this context, influence of atrazine on defence mechanisms was analyzed in Pacific oysters, Crassostrea gigas. Atrazine was tested in vitro and in vivo on oyster haemocytes, and its effects were analyzed by flow cytometry. Haemocyte viability, cell cycle and cellular activities were monitored. Atrazine induced no significant effect in oyster under tested conditions except for peroxidase activity.

  8. Crassostrea virginica grazing on toxic and non-toxic diatoms.

    PubMed

    Thessen, A E; Soniat, T M; Dortch, Q; Doucette, G J

    2010-01-01

    Despite high abundances of toxic Pseudo-nitzschia spp. over Louisiana oyster beds (Crassostrea virginica; eastern oyster) there have been no documented cases of amnesic shellfish poisoning (ASP) in the state. Two possible explanations are that oysters do not readily feed on long pointed chains of Pseudo-nitzschia cells or they discriminate against toxic cells while grazing. To test these hypotheses, short-term grazing experiments were conducted with several diatoms, including the domoic acid (DA)-producing Pseudo-nitzschia multiseries (1.31+/-0.057 pg DA cell(-1)) and the non-toxic Pseudo-nitzschia delicatissima, Thalassiosira weissflogii, and Ditylum brightwellii. Grazing rates on the small centric species T. weissflogii were significantly higher than on the larger and pointier D. brightwellii and either Pseudo-nitzschia species. Grazing on toxic P. multiseries and non-toxic P. delicatissima was not significantly different. Pseudofeces production was higher and feces production was occasionally lower in oysters fed Pseudo-nitzschia spp. than in oysters fed the other two diatoms. Our data demonstrate lower filtration rates of C. virginica on Pseudo-nitzschia spp. relative to the other diatoms tested and comparable filtration on toxic and non-toxic Pseudo-nitzschia spp. These findings suggest that eastern oysters do not discriminate amongst food types due to DA content.

  9. Presence of Octopamine and an Octopamine Receptor in Crassostrea virginica

    PubMed Central

    Pryce, Kerri; Samuel, Dahniel; Lagares, Elsie; Myrthil, Mathilde; Bess, Fiana; Harris, Ave; Welsh, Christopher; Carroll, Margaret A; Catapane, Edward J

    2015-01-01

    Octopamine is a biogenic amine first identified in octopus. It has been well studied in arthropods and a few gastropods, serving as a neurotransmitter and hormone. The presence of octopamine has rarely been reported in bivalves and has not been reported in Crassostrea virginica. We utilized HPLC to identify and measure octopamine in cerebral ganglia, visceral ganglia, gill, palps, mantle, heart and hemolymph of C. virginica. Endogenous octopamine levels increased when animals were treated with tyramine, an octopamine precursor. A preliminary study in our lab found that octopamine has a cardio-excitatory action on C. virginica heart. In the present study we also used immunoblotting techniques to identify an octopamine-like receptor (Pan TAAR, trace amine-associated receptor) in oyster heart. The study confirms the presence of octopamine in the nervous system, innervated organs and hemolymph of C. virginica and identifies the presence of an octopamine-like receptor in heart, strengthening the contention that octopamine is important in the physiology of C. virginica as it is in other invertebrates. PMID:26594670

  10. DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

    PubMed Central

    Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

    2016-01-01

    The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change. PMID:27666088

  11. 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.

  12. DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas.

    PubMed

    Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

    2016-09-26

    The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

  13. DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

    NASA Astrophysics Data System (ADS)

    Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

    2016-09-01

    The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

  14. A new non-phagocytic TLR6 with broad recognition ligands from Pacific oyster Crassostrea gigas.

    PubMed

    Wang, Weilin; Zhang, Tao; Wang, Lingling; Xu, Jiachao; Li, Meijia; Zhang, Anguo; Qiu, Limei; Song, Linsheng

    2016-12-01

    Toll like receptors (TLRs) are evolutionarily prevalent recognition molecules in the Animalia and Plantae kingdom, which play vital roles in immune defense and homeostasis maintenance. Recently, the expansion of TLRs has been reported in invertebrate genomes, but the characters and immune functions of these expanded TLRs were still not well known. In the present study, a new member of TLR family with five LRR domains was identified in Crassostrea gigas (designated CgTLR6). It shared homology with TLRs from other organisms with the closest phylogenic relationship with molluscan TLRs. The recombinant protein of CgTLR6 (rCgTLR6) displayed direct bind activity to gram-negative bacteria Vibrio anguillarum and Vibrio splendidus, gram-positive bacteria Staphylococci aureus and Micrococcus luteus, and fungi Pichia pastoris, but not to fungi Yarrowia lipolytica. It also exhibited affinity to lipopolysaccharide (LPS) and peptidoglycan (PGN), while no affinity to mannan (MAN). The mRNA of CgTLR6 was mainly detected in hemocytes and hepatopancreas, and was significantly induced (p < 0.01) in hemocytes after the oyster was stimulated with LPS, PGN or bacteria V. splendidus. Immunofluorescence analysis indicated that CgTLR6 was mainly located at the membrane of hemocytes. The blockage of CgTLR6 by anti-rCgTLR6 antibody did not significantly inhibit the phagocytic rates of hemocytes toward recognized gram-negative bacteria V. anguillarum and V. splendidus, and unrecognized fungi Y. lipolytica. These results collectively implied that CgTLR6 was a novel non-phagocytic receptor of C. gigas to mediate humoral immune response by recognizing pathogen-associated molecular patterns on the invaders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Cellular responses and disease expression in oysters (Crassostrea virginica) exposed to suspended field contaminated sediments.

    PubMed

    Chu, Fu-Lin E; Volety, Aswani K; Hale, Robert C; Huang, Yongqin

    2002-02-01

    Exposure of oysters to water soluble fractions derived from field-contaminated sediments (FCS) containing predominantly lower molecular weight organic aromatic compounds, has been previously demonstrated to enhance pre-existing infections caused by the protozoan parasite, Perkinsus marinus (Dermo), and the prevalence of experimentally induced infections. To further explore the role of pollution on the onset and progression of disease, effects of suspended FCS from an estuarine creek in Virginia, USA, dominated by higher molecular weight polycyclic aromatic hydrocarbons (PAHs) on cellular responses and Dermo disease expression in oysters (Crassostrea virginica) were examined. Sediments were collected from a PAH polluted estuarine creek in Virginia, USA. To test effects on cellular response, oysters from Maine were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 70.2, 105, or 140 microg PAHs, respectively) for 5, 10, 20, and 40 days. Hemocyte activities and plasma lipid, protein and lactate dehydrogenase (LDH) levels were then measured. Exposure stimulated neutral red uptake, MTT reduction, and 3H-leucine incorporation in oyster hemocytes at various exposure times, but did not affect the plasma protein, lipid and LDH levels. To test effects on Dermo expression, oysters from a Dermo enzootic area, with an initial estimated infection prevalence of 39%, were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 75.0, 113, or 150 microg PAHs, respectively) for 30 days. Exposure enhanced disease expression in oysters. However, no significant change was noted in any measured cellular or humoral parameters.

  17. 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.

  18. 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

  19. Construction and evaluation of a high-density SNP array for the Pacific oyster (Crassostrea gigas)

    PubMed Central

    Li, Chunyan; Wang, Wei; Li, Busu; Li, Li

    2017-01-01

    Single nucleotide polymorphisms (SNPs) are widely used in genetics and genomics research. The Pacific oyster (Crassostrea gigas) is an economically and ecologically important marine bivalve, and it possesses one of the highest levels of genomic DNA variation among animal species. Pacific oyster SNPs have been extensively investigated; however, the mechanisms by which these SNPs may be used in a high-throughput, transferable, and economical manner remain to be elucidated. Here, we constructed an oyster 190K SNP array using Affymetrix Axiom genotyping technology. We designed 190,420 SNPs on the chip; these SNPs were selected from 54 million SNPs identified through re-sequencing of 472 Pacific oysters collected in China, Japan, Korea, and Canada. Our genotyping results indicated that 133,984 (70.4%) SNPs were polymorphic and successfully converted on the chip. The SNPs were distributed evenly throughout the oyster genome, located in 3,595 scaffolds with a length of ~509.4 million; the average interval spacing was 4,210 bp. In addition, 111,158 SNPs were distributed in 21,050 coding genes, with an average of 5.3 SNPs per gene. In comparison with genotypes obtained through re-sequencing, ~69% of the converted SNPs had a concordance rate of >0.971; the mean concordance rate was 0.966. Evaluation based on genotypes of full-sib family individuals revealed that the average genotyping accuracy rate was 0.975. Carrying 133 K polymorphic SNPs, our oyster 190K SNP array is the first commercially available high-density SNP chip for mollusks, with the highest throughput. It represents a valuable tool for oyster genome-wide association studies, fine linkage mapping, and population genetics. PMID:28328985

  20. The immunomodulation of inducible hydrogen sulfide in Pacific oyster Crassostrea gigas.

    PubMed

    Sun, Zhibin; Wang, Lingling; Zhang, Tao; Zhou, Zhi; Jiang, Qiufen; Yi, Qilin; Yang, Chuanyan; Qiu, Limei; Song, Linsheng

    2014-10-01

    Hydrogen sulfide (H2S) is an important gasotransmitter, which plays indispensable roles in cardiovascular, nervous and immune systems of vertebrates. However, the information about the immunomodulation of H2S in invertebrates is still very limited. In the present study, the temporal expression profile of cystathionine γ lyase in oyster Crassostrea gigas (CgCSE) was investigated after the oysters were stimulated by lipopolysaccharide. The expression levels of CgCSE mRNA transcripts in hemocytes increased significantly at 12h (1.31-fold of the PBS group, P<0.05) after LPS stimulation. The immunomodulation of inducible H2S in oyster was examined by monitoring the alterations of both cellular and humoral immune parameters in response to the stimulations of LPS, LPS+Na2S and LPS+propargylglycine (PAG). The total hemocyte counts (THC) and hemolymph PO activity increased significantly after LPS stimulation, and the increase could be further enhanced by adding PAG, while inhibited by appending Na2S. The phagocytosis activity of hemocytes was also increased firstly after LPS treatment, and the increase was enhanced by adding Na2S but inhibited after appending PAG. The anti-bacterial activity in hemolymph increased at 3h post LPS treatment, and then decreased after adding PAG. The total SOD activity of hemolymph was also elevated at 6h post LPS treatment, and the elevated activity was depressed by adding Na2S. These results collectively indicated that H2S might play crucial roles in the immune response of oyster via modulating the turnover and phagocytosis of hemocytes, and regulating the anti-bacterial activity and proPO activation in the hemolymph.

  1. SEASONAL VARIATION IN LYSOSOMAL DESTABILIZATION IN OYSTERS, CRASSOSTREA VIRGINICA. (R826201)

    EPA Science Inventory

    Lysosomal destabilization assays have been used as valuable biomarkers of pollutant exposures in a variety of bivalve and fish species. The responses of oysters, Crassostrea virginica, deployed at and native to various reference and degraded sites were evaluated for lys...

  2. SEASONAL VARIATION IN LYSOSOMAL DESTABILIZATION IN OYSTERS, CRASSOSTREA VIRGINICA. (R826201)

    EPA Science Inventory

    Lysosomal destabilization assays have been used as valuable biomarkers of pollutant exposures in a variety of bivalve and fish species. The responses of oysters, Crassostrea virginica, deployed at and native to various reference and degraded sites were evaluated for lys...

  3. 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...

  4. 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 ...

  5. 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...

  6. 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...

  7. 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 ...

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. Genetic differentiation and phylogeography of partially sympatric species complex Rhizophora mucronata Lam. and R. stylosa Griff. using SSR markers.

    PubMed

    Wee, Alison K S; Takayama, Koji; Chua, Jasher L; Asakawa, Takeshi; Meenakshisundaram, Sankararamasubramanian H; Onrizal; Adjie, Bayu; Ardli, Erwin Riyanto; Sungkaew, Sarawood; Malekal, Norhaslinda Binti; Tung, Nguyen Xuan; Salmo, Severino G; Yllano, Orlex Baylen; Saleh, M Nazre; Soe, Khin Khin; Tateishi, Yoichi; Watano, Yasuyuki; Baba, Shigeyuki; Webb, Edward L; Kajita, Tadashi

    2015-03-29

    Mangrove forests are ecologically important but globally threatened intertidal plant communities. Effective mangrove conservation requires the determination of species identity, management units, and genetic structure. Here, we investigate the genetic distinctiveness and genetic structure of an iconic but yet taxonomically confusing species complex Rhizophora mucronata and R. stylosa across their distributional range, by employing a suite of 20 informative nuclear SSR markers. Our results demonstrated the general genetic distinctiveness of R. mucronata and R. stylosa, and potential hybridization or introgression between them. We investigated the population genetics of each species without the putative hybrids, and found strong genetic structure between oceanic regions in both R. mucronata and R. stylosa. In R. mucronata, a strong divergence was detected between populations from the Indian Ocean region (Indian Ocean and Andaman Sea) and the Pacific Ocean region (Malacca Strait, South China Sea and Northwest Pacific Ocean). In R. stylosa, the genetic break was located more eastward, between populations from South and East China Sea and populations from the Southwest Pacific Ocean. The location of these genetic breaks coincided with the boundaries of oceanic currents, thus suggesting that oceanic circulation patterns might have acted as a cryptic barrier to gene flow. Our findings have important implications on the conservation of mangroves, especially relating to replanting efforts and the definition of evolutionary significant units in Rhizophora species. We outlined the genetic structure and identified geographical areas that require further investigations for both R. mucronata and R. stylosa. These results serve as the foundation for the conservation genetics of R. mucronata and R. stylosa and highlighted the need to recognize the genetic distinctiveness of closely-related species, determine their respective genetic structure, and avoid artificially promoting

  13. 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).

  14. Uptake of heavy metals and PAHs from the Deepwater Horizon oil spill by soft tissues and shells of the coastal oyster Crassostrea virginica

    NASA Astrophysics Data System (ADS)

    Roopnarine, P. D.; Roopnarine, D.; Gillikin, D. P.; Anderson, L. C.; Ballester, M.; Goodwin, D. H.

    2011-12-01

    The Deepwater Horizon oil spill, which dumped more than 600,000 tons of crude oil into the Gulf of Mexico (GOM) between April and August 2010 is the largest accidental spill in history. While immediate environmental impacts of the spill, such as direct and fatal fouling of wildlife and the physical contamination of coastal areas were easily observed, any long-term effects of the spill are still being determined. Here we examined the incorporation of spill components into the shells and soft tissues of the American oyster, Crassostrea virginica. Specifically, we searched for evidence that heavy metals or polycyclic aromatic hydrocarbons (PAHs) are present in the carbonate shell (metals only) or various tissues of the oyster. Crassostrea virginica is a species of great economic significance, and is also an important basal primary consumer in the coastal GOM food web. Preliminary evidence presented in 2010 compared shells of specimens from the GOM collected in the 20th century, May 2010 prior to landfall of Deepwater oil on the Louisiana coast, and August 2010. Those results indicated that specimens collected in August 2010 had relatively higher concentrations of vanadium (V) and lead (Pb) in their shells compared to historical and May 2010 specimens. Those results have now been confirmed, and we show that specimens collected in August 2010, after exposure to the spill, have significantly higher concentrations of V, Pb and chromium (Cr) in their shells. Furthermore, examination of soft tissues shows that V, Pb and cobalt (Co) are present in significantly higher concentrations in gill and muscle tissues of August 2010 specimens. Analyses of PAH concentrations are currently being conducted on the soft tissues of specimens collected in May and August 2010, as well as specimens collected outside of spill-affected areas in the GOM. Ultimately, compilation of contaminant occurrences and concentrations coupled with food web models will allow us to predict the potential for

  15. Successful cryopreservation of Pacific oyster (Crassostrea gigas) oocytes.

    PubMed

    Tervit, H R; Adams, S L; Roberts, R D; McGowan, L T; Pugh, P A; Smith, J F; Janke, A R

    2005-10-01

    Protocols for cryopreservation of sperm and oocytes would provide the ultimate control over parental crosses in selective breeding programmes. Sperm freezing is routine for many species, but oocyte freezing remains problematic, with virtually zero success in aquatic species to date. This paper describes the development of a successful protocol for cryopreserving high concentrations of Pacific oyster (Crassostrea gigas) oocytes. Ethylene glycol (10%) and dimethyl sulfoxide (15%) were found to be the most effective cryoprotectants resulting in post-thaw fertilization rates of 51.0+/-8.0 and 45.1+/-8.3%, respectively. Propylene glycol was less effective and methanol resulted in zero fertilization post-thaw. The use of Milli-Q water rather than seawater as a base medium significantly improved fertilization (20.4+/-3.0 and 8.7+/-2.2%, respectively) as did the inclusion of a 5 min isothermal hold at -10 or -12 degrees C (35.9+/-5.0 and 31.9+/-4.6%, respectively). The optimal cooling rate post-hold was 0.3 degrees C min(-1), with virtually zero post-thaw fertilization with cooling rates of 3 and 6 degrees C min(-1). Using an optimized protocol, post-thaw fertilization rates for oocytes from eight individual females ranged from 0.8 to 74.5% and D-larval yields from 0.1 to 30.1%. For three individuals, larvae were reared through to spat. Development of D-larvae to eyed larvae and spat was similar for larvae produced from unfrozen (24.8+/-4.1% developed to eyed larvae and 16.5+/-3.2% to spat) and cryopreserved (28.4+/-0.6 and 18.7+/-0.5%, respectively) oocytes. The ability to cryopreserve large quantities of oyster oocytes represents a major advance in cryobiology and selective breeding.

  16. 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

  17. Phylogenetic Analysis of Molluscan Metallothioneins: Evolutionary Insight from Crassostrea virginica.

    PubMed

    Jenny, Matthew J; Payton, Samantha L; Baltzegar, David A; Lozier, Jeffrey D

    2016-10-01

    Mechanisms by which organisms genetically adapt to environmental conditions are of fundamental importance to studies of evolutionary biology and environmental physiology. Natural selection acts on existing genetic variation leading to adaptation through selection of new mutations that confer beneficial advantages to populations. The American oyster, Crassostrea virginica, is an excellent model to investigate interactions between environmental and ecological factors as driving forces for natural selection. A great example of this is represented by the diversity of C. virginica metallothioneins (CvMT), metal-binding proteins involved in homeostasis and tolerance, that have resulted from a series of duplication events to produce the greatest structural diversity of MT proteins found in a single species. We present phylogenetic evidence of two distinct ancestral β-domain MTs that gave rise to a variety of ββ and αβ CvMT proteins, as well as CvMT-II proteins consisting solely of one to four α-domains. Furthermore, we annotate the complete locus containing the paralogous CvMT-I, -II, and -IV genes, providing supporting evidence of a hypothesized series of exon and gene duplication events that gave rise to the various CvMT-I and -II isoforms. We also highlight unique MT expression profiles from four separate C. virginica populations to demonstrate differences in gene diversity and copy number which appear to be enriched in southeastern U.S. oyster populations. These observations contribute to a better understanding of the molecular mechanisms leading to adaptation in organisms that experience substantial environmental stress, with a specific focus on evolutionary adaptations of gene structure.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  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. 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...

  5. Pseudoroseovarius zhejiangensis gen. nov., sp. nov., a novel alpha-proteobacterium isolated from the chemical wastewater, and reclassification of Roseovarius crassostreae as Pseudoroseovarius crassostreae comb. nov., Roseovarius sediminilitoris as Pseudoroseovarius sediminilitoris comb. nov. and Roseovarius halocynthiae as Pseudoroseovarius halocynthiae comb. nov.

    PubMed

    Sun, Cong; Pan, Jie; Zhang, Xin-Qi; Su, Yue; Wu, Min

    2015-08-01

    A Gram-stain negative, aerobic, non-motile and ovoid- to rod-shaped bacterial strain, designated JB3(T), was isolated from a wastewater sample collected from the biochemical reaction basin of Haiyan fine chemical factory in Zhejiang, China. Strain JB3(T) was found to grow optimally at pH 7.0-8.0, at 28 °C and in the presence of 1.0-2.0 % (w/v) NaCl. Chemotaxonomic analysis showed that strain JB3(T) contains ubiquinone-10 (>99 %) as the predominant respiratory quinone and C18:1 ω7c (70.9 %) as the most abundant fatty acid. The polar lipids of strain JB3(T) were identified as phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an aminophospholipid, an unidentified aminolipid, four unidentified phospholipids and three unidentified lipids. The DNA G+C content of strain JB3(T) was determined to be 68.1 mol%. The 16S rRNA gene sequence similarities between the isolate and Roseovarius crassostreae DSM 16950(T), Roseovarius sediminilitoris KCTC 23959(T) and Roseovarius halocynthiae MA1-10(T) were found to be 97.1, 96.8 and 96.2 %, respectively. Morevoer, the similarity between strain JB3(T) and the type strain of the genus Roseovarius (Roseovarius tolerans DSM 11457(T)) was found to be 93.8 %. The phylogenetic trees reconstructed with all three treeing methods showed that strain JB3(T) constituted a different taxon, which was separate from other taxa with validly published names, and formed a cluster with R. crassostreae DSM 16950(T), R. sediminilitoris KCTC 23959(T) and R. halocynthiae MA1-10(T). These three species were not placed within the phylogenetic cluster formed by R. tolerans DSM 11457(T). Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain JB3(T) is clearly distinct from species of the genus Roseovarius. On the basis of these features, we propose strain JB3(T) represents a novel species of a novel genus with the name Pseudoroseovarius zhejiangensis gen. nov., sp

  6. Connectivity Among Three Restored Crassostrea Virginica Bars in the Severn River Estuary: Implications for Oyster Recovery Efforts

    DTIC Science & Technology

    2008-06-30

    planted in 2002) through time. The larger size classes represented by CC 10-07 may indicate that the part of the reef containing oysters grown in...Connectivity among three restored Crassostrea virginica bars in the Severn River Estuary; Implications for oyster recovery efforts...restored Crassostrea virginica bars in the Severn River Estuary: Implications for oyster recovery efforts 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  7. Detection of undescribed ostreid herpesvirus 1 (OsHV-1) specimens from Pacific oyster, Crassostrea gigas.

    PubMed

    Martenot, Claire; Lethuillier, Ophélie; Fourour, Sarah; Oden, Elise; Trancart, Suzanne; Travaillé, Emmanuelle; Houssin, Maryline

    2015-11-01

    The ostreid herpesvirus 1 (OsHV-1) and variants were implicated in mass mortality affecting the young Pacific cupped oysters, Crassostrea gigas, in European countries and those around the world. From 2008 onwards, oyster mortality had greatly increased on the French coast and was associated with the detection of a new OsHV-1 variant, entitled OsHV-1 μVar. The OsHV-1 μVar is predominant in oysters; however, other OsHV-1 variants have been detected in samples collected during mortality periods or collected out of mortality periods in France, Ireland, Spain, Portugal, Italy, Mexico, United States, South Korea, Australia, and New Zealand. A retrospective study conducted on 1047 OsHV-1 specimens sampled mainly in France between 2009 and 2012, revealed 17 undescribed OsHV-1 variants found in 65 oyster samples. These specimens presented point mutations situated downstream and upstream from the microsatellite area in the C region (ORF 4/5) which were different from the OsHV-1 reference and the OsHV-1 μVar. In the present work, investigation was performed to further characterize these OsHV-1 specimens by sequencing two habitually targeted regions to study genetic polymorphism of the virus: ORF 41/42 and ORF 35-38. An OsHV-1 variant detected in six oyster samples, contained a nucleotide substitution in the C region which impacted the amino acid sequence and might modify the function of the unknown protein encoding by ORF 4. For the ORF 41/42 region, only two specimens presented a synonymous mutation in comparison with the OsHV-1 μVar. All specimens contained the same deletion with the OsHV-1 μVar in ORF 35-38. Then, a phylogenetic analysis based on the C region was performed to investigate the distribution of undescribed specimens among 21 OsHV-1 DNA sequences notified in GenBank and collected from different countries (France, Japan, New Zealand, China, Ireland, and United States) between 1995 and 2012. All analyzed samples and the OsHV-1 μVar were placed in the same

  8. 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.

  9. 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

  10. Organochlorine compounds in blue mussels, Mytilus edulis, and Pacific oysters, Crassostrea gigas, from seven sites in the Lower Saxonian Wadden Sea, Southern North Sea.

    PubMed

    Dörr, Barbara; Liebezeit, Gerd

    2009-12-01

    Blue mussels (Mytilus edulis) and Pacific oysters (Crassostrea gigas) collected at seven locations in the Lower Saxonian Wadden Sea in January and February 2007 were analysed for organochlorine compounds. Contaminants were present in all samples, albeit with variable amounts and composition. The highest values were found in the Jade Bay. Congener PCB 153 was the contaminant which had the highest content of all organochlorines tested (475.75-937.39 ng/g lipid). DDT was detected in one sample only while DDD and DDE were found in all samples, the latter with contents up to 351.34 ng/g lipid. No clear differentiation could be made in terms of accumulation of organochlorines for M. edulis and C. gigas. Comparison with data from 2001 to 2006 showed an increase in 2007, which may be due to the different season the samples were taken.

  11. Transcriptome of American oysters, Crassostrea virginica, in response to bacterial challenge: insights into potential mechanisms of disease resistance.

    PubMed

    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.

  12. Rising water temperatures, reproduction and recruitment of an invasive oyster, Crassostrea gigas, on the French Atlantic coast.

    PubMed

    Dutertre, Mickaël; Beninger, Peter G; Barillé, Laurent; Papin, Mathias; Haure, Joël

    2010-02-01

    The recent appearance and invasion of feral oysters (Crassostrea gigas) along the northern European Atlantic coast, underscores the necessity to investigate the relationship between environmental variables, reproductive physiology, larval development and recruitment. We studied these relationships at both high (HT) and intermediate (IT) - turbidity sites, through historical data on water temperatures, multi-parameter environmental probes, histological analyses, and field collections of planktonic larvae and settled post-larvae in 2005 and 2006. A progressive warming trend was observed, especially since 1995, when oyster proliferation first became severe. Threshold temperatures for oocyte growth, larval development and settlement were achieved in both 2005 and 2006. The HT site showed greater numbers of larvae and post-larvae than the IT site for both years, with the highest numbers of post-larvae observed at both sites during the warmer summer of 2006. These results suggest that increased temperatures in northern European waters allow successful reproduction, larval development, and recruitment of C. gigas. High turbidity conditions further enhance this success. 2009 Elsevier Ltd. All rights reserved.

  13. Experimental infection of Pacific oyster Crassostrea gigas spat by ostreid herpesvirus 1: demonstration of oyster spat susceptibility.

    PubMed

    Schikorski, David; Renault, Tristan; Saulnier, Denis; Faury, Nicole; Moreau, Pierrick; Pépin, Jean-François

    2011-02-07

    In 2008 and 2009, acute mortalities occurred in France among Pacific cupped oyster, Crassostrea gigas, spat. Different hypothesis including the implication of environmental factors, toxic algae and/or pathogens have been explored. Diagnostic tests indicated that OsHV-1 including a particular genotype, termed OsHV-1 μVar, was detected in most of samples and especially in moribund oysters with the highlighting of virus particles looking like herpes viruses by TEM examination. In this study, an experimental protocol to reproduce OsHV-1 infection in laboratory conditions was developed. This protocol was based on the intramuscular injection of filtered (0.22 μm) tissue homogenates prepared from naturally OsHV-1 infected spat collected on French coasts during mortality outbreaks in 2008. Results of the experimental trials showed that mortalities were induced after injection. Moreover, filtered tissue homogenates induced mortalities whereas the same tissue homogenates exposed to an ultraviolet (UV) treatment did not induce any mortality suggesting that oyster spat mortalities require the presence of a UV sensitive agent. Furthermore, analysis of injected oyster spat revealed the detection of high amounts of OsHV-1 DNA by real-time quantitative PCR. Finally, TEM analysis demonstrated the presence of herpes virus particles. The developed protocol allowed to maintain sources of infective virus which can be useful for the development of further studies concerning the transmission and the development of OsHV-1 infection.

  14. Experimental infection of Pacific oyster Crassostrea gigas spat by ostreid herpesvirus 1: demonstration of oyster spat susceptibility

    PubMed Central

    2011-01-01

    In 2008 and 2009, acute mortalities occurred in France among Pacific cupped oyster, Crassostrea gigas, spat. Different hypothesis including the implication of environmental factors, toxic algae and/or pathogens have been explored. Diagnostic tests indicated that OsHV-1 including a particular genotype, termed OsHV-1 μVar, was detected in most of samples and especially in moribund oysters with the highlighting of virus particles looking like herpes viruses by TEM examination. In this study, an experimental protocol to reproduce OsHV-1 infection in laboratory conditions was developed. This protocol was based on the intramuscular injection of filtered (0.22 μm) tissue homogenates prepared from naturally OsHV-1 infected spat collected on French coasts during mortality outbreaks in 2008. Results of the experimental trials showed that mortalities were induced after injection. Moreover, filtered tissue homogenates induced mortalities whereas the same tissue homogenates exposed to an ultraviolet (UV) treatment did not induce any mortality suggesting that oyster spat mortalities require the presence of a UV sensitive agent. Furthermore, analysis of injected oyster spat revealed the detection of high amounts of OsHV-1 DNA by real-time quantitative PCR. Finally, TEM analysis demonstrated the presence of herpes virus particles. The developed protocol allowed to maintain sources of infective virus which can be useful for the development of further studies concerning the transmission and the development of OsHV-1 infection. PMID:21314910

  15. Detection of different variants of Ostreid Herpesvirus 1 in the Pacific oyster, Crassostrea gigas between 2008 and 2010.

    PubMed

    Martenot, Claire; Oden, Elise; Travaillé, Emmanuelle; Malas, Jean-Paul; Houssin, Maryline

    2011-09-01

    Since summer 2008, high mortality rates of young Pacific oysters Crassostrea gigas have been recorded in association with the detection of the Ostreid Herpesvirus 1 (OsHV-1). A new variant called μVar has been recently described, characterized mainly by 12 consecutive deletions followed by one deletion of an adenine in the C region. The purpose of this study is to characterize the genotype (variants or OsHV-1 reference) of 300 positive samples of C. gigas analyzed between July 2008 and July 2010 collected along the French, Jersey, and Irish coasts. Samples were quantified by TaqMan PCR, amplified with conventional PCR, targeting the area of the deletion, and then sequenced. Eighty-seven percent of the samples were characterized and the OsHV-1 μVar was detected in 257 oyster samples. The genotype OsHV-1 reference was never detected during the 25 months of the present survey. Thirty-eight samples could not be determined and the majority of them had a low viral load. A novel genotype containing only 9 consecutive deletions named OsHV-1 μVar Δ9 was found in 5 samples. These observations indicate the emergence of different OsHV-1 variants.

  16. 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.

  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.

  18. Lethal and sub-lethal effects of Deepwater Horizon slick oil and dispersant on oyster (Crassostrea virginica) larvae.

    PubMed

    Vignier, J; Soudant, P; Chu, F L E; Morris, J M; Carney, M W; Lay, C R; Krasnec, M O; Robert, R; Volety, A K

    2016-09-01

    In April 2010, crude oil was spilled from the Deepwater Horizon (DWH) oil platform for 87 days, coincident with the spawning season and recruitment of the oyster, Crassostrea virginica, in the Gulf of Mexico. Impacts of acute exposures to surface-collected DWH oil (HEWAF), dispersed oil (CEWAF) and dispersant alone (Corexit 9500A(®)) on planktonic larval stages of C. virginica (veliger, umbo and pediveliger) were tested in the laboratory. Exposures to HEWAF, CEWAF and dispersant were toxic to larvae impairing growth, settlement success and ultimately survival. Larval growth and settlement were reduced at concentrations of tPAH50 ranging from 1.7 to 106 μg L(-1) for HEWAF and 1.1-35 μg L(-1) for CEWAF, concentrations well within the range of water sampled during the DWH oil spill. Sublethal effects induced by oil and dispersant could have significant ecological implications on oyster populations and on the whole estuarine ecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. High levels of icosapentaenoic acid in the lipids of oyster Crassostrea gigas ranging over both Japan and France.

    PubMed

    Saito, Hiroaki; Marty, Yanic

    2010-01-01

    The lipid and fatty acids of the Pacific oyster, Crassostrea gigas, collected both in Japan and France, were analyzed. Triacylglycerols and sterols were the major classes in the neutral lipids of both populations of C. gigas between the two countries, and they had significant levels of phospholipids (phosphatidylethanolamine and phosphatidylcholine) with ceramideaminoethylphosphonate in their polar tissue lipids. The differences of 18:3n-3 and 22:6n-3 (docosahexaenoic acid; DHA) levels in the depot triacylglycerols suggest the influence of dietary phytoplankton in different environments of the two countries. Although the levels of the fatty acids slightly differed, that of 20:5n-3 (icosapentaenoic acid; EPA, 20.5-24.8%) in the triacylglycerols was specifically the highest fatty acid in all the samples. The major polyunsaturated fatty acids in the polar lipids of all samples were EPA (13.2-17.8% for phosphatidylethanolamine and 13.4-22.7% for phosphatidylcholine) and DHA (18.9-26.8% for phosphatidylethanolamine and 13.1-22.5% for phosphatidylcholine). The fluctuation of total PUFA levels in the polar lipids between samples of both countries suggests the influence of diet. In addition, the consistently high EPA levels in the phospholipids may compensate for the variation in DHA levels.

  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. δ15N Values in Crassostrea virginica Shells Provides Early Direct Evidence for Nitrogen Loading to Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Black, H. D.; Andrus, C. F. T.; Lambert, W. J.; Rick, T. C.; Gillikin, D. P.

    2017-03-01

    Crassostrea virginica is one of the most common estuarine bivalves in the United States’ east coast and is frequently found in archaeological sites and sub-fossil deposits. Although there have been several sclerochronological studies on stable carbon and oxygen isotopes in the shells of this species, less is known about δ15N values within their shells, which could be a useful paleoenvironmental proxy to assess estuarine nitrogen dynamics. Modern C. virginica samples were collected in Chesapeake Bay for comparison with archaeological shells from nearby sites ranging in age from ~100 to 3,200 years old. Left valves were sampled by milling the hinge area and the resulting powder was analyzed for %N and δ15N values. Comparison of δ15N values between C. virginica shells shows relatively constant values from ~1250 BC to ~1800 AD. After ~1800 AD, there are rapid increases in 15N enrichment in the shells, which continue to increase in value up to the modern shell values. The increase in δ15N values is evidence of early anthropogenic impact in Chesapeake Bay. These results corroborate the observation that coastal nitrogen pollution occurred earlier than the 19th century and support the use of oyster shell δ15N values as a useful environmental proxy.

  2. δ(15)N Values in Crassostrea virginica Shells Provides Early Direct Evidence for Nitrogen Loading to Chesapeake Bay.

    PubMed

    Black, H D; Andrus, C F T; Lambert, W J; Rick, T C; Gillikin, D P

    2017-03-10

    Crassostrea virginica is one of the most common estuarine bivalves in the United States' east coast and is frequently found in archaeological sites and sub-fossil deposits. Although there have been several sclerochronological studies on stable carbon and oxygen isotopes in the shells of this species, less is known about δ(15)N values within their shells, which could be a useful paleoenvironmental proxy to assess estuarine nitrogen dynamics. Modern C. virginica samples were collected in Chesapeake Bay for comparison with archaeological shells from nearby sites ranging in age from ~100 to 3,200 years old. Left valves were sampled by milling the hinge area and the resulting powder was analyzed for %N and δ(15)N values. Comparison of δ(15)N values between C. virginica shells shows relatively constant values from ~1250 BC to ~1800 AD. After ~1800 AD, there are rapid increases in (15)N enrichment in the shells, which continue to increase in value up to the modern shell values. The increase in δ(15)N values is evidence of early anthropogenic impact in Chesapeake Bay. These results corroborate the observation that coastal nitrogen pollution occurred earlier than the 19th century and support the use of oyster shell δ(15)N values as a useful environmental proxy.

  3. δ15N Values in Crassostrea virginica Shells Provides Early Direct Evidence for Nitrogen Loading to Chesapeake Bay

    PubMed Central

    Black, H. D.; Andrus, C. F. T.; Lambert, W. J.; Rick, T. C.; Gillikin, D. P.

    2017-01-01

    Crassostrea virginica is one of the most common estuarine bivalves in the United States’ east coast and is frequently found in archaeological sites and sub-fossil deposits. Although there have been several sclerochronological studies on stable carbon and oxygen isotopes in the shells of this species, less is known about δ15N values within their shells, which could be a useful paleoenvironmental proxy to assess estuarine nitrogen dynamics. Modern C. virginica samples were collected in Chesapeake Bay for comparison with archaeological shells from nearby sites ranging in age from ~100 to 3,200 years old. Left valves were sampled by milling the hinge area and the resulting powder was analyzed for %N and δ15N values. Comparison of δ15N values between C. virginica shells shows relatively constant values from ~1250 BC to ~1800 AD. After ~1800 AD, there are rapid increases in 15N enrichment in the shells, which continue to increase in value up to the modern shell values. The increase in δ15N values is evidence of early anthropogenic impact in Chesapeake Bay. These results corroborate the observation that coastal nitrogen pollution occurred earlier than the 19th century and support the use of oyster shell δ15N values as a useful environmental proxy. PMID:28281649

  4. A GTP-dependent Phosphoenolpyruvate Carboxykinase from Crassostrea gigas Involved in Immune Recognition.

    PubMed

    Lv, Zhao; Qiu, Limei; Wang, Weilin; Liu, Zhaoqun; Xue, Zhuang; Yu, Zichao; Song, Xiaorui; Chen, Hao; Wang, Lingling; Song, Linsheng

    2017-12-01

    Phosphoenolpyruvate carboxykinase (PEPCK) is well known as a key enzyme involved in the metabolic pathway of gluconeogenesis in organisms, but the information about its involvement in immune response is still very limited. In the present study, a novel PEPCK homolog named CgPEPCK was identified from oyster Crassostrea gigas. The deduced amino acid sequence of CgPEPCK shared 52%-74% similarities with those from other known PEPCKs. There were one conserved guanosine triphosphate (GTP) binding site, one substrate binding site, one metal binding site and one active site in CgPEPCK. The mRNA transcripts of CgPEPCK were constitutively expressed in all the tested tissues including hemolymph, mantle, gill, muscle, gonad and hepatopancreas. CgPEPCK proteins were mainly distributed in adductor muscle, gonad, gill and mantle, and rarely detected in hepatopancreas by using immunohistochemical analysis. After the stimulations with lipopolysaccharide (LPS), peptidoglycan (PGN), Vibrio splendidus and V. anguillarum, CgPEPCK transcripts in hemocytes were significantly up-regulated and peaked at 6 h (LPS, 9.62-fold, p < 0.01), 9 h (PGN, 4.25-fold, p < 0.01), 12 h (V. splendidus, 5.72-fold, p < 0.01), 3 h (V. anguillarum, 2.87-fold, p < 0.01), respectively. The recombinant CgPEPCK protein (rCgPEPCK) exhibited Mn(2+)/Mg(2+) dependent GTP binding activity, and the activities to bind LPS and PGN, but not β-1,3-glucan (GLU), lipoteichoic acid (LTA), mannan (MAN) nor polyinosinic-polycytidylic (Poly I: C). It could also bind Escherichia coli, Staphylococcus aureus, Micrococcus luteus and significantly inhibit their growth. All these results collectively suggested that CgPEPCK could not only exert GTP binding activity involved in gluconeogenesis, but also mediate the bacteria recognition and clearance in immune response of oysters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Mortality and herpesvirus infections of the Pacific oyster Crassostrea gigas in Tomales Bay, California, USA.

    PubMed

    Burge, Colleen A; Griffin, Frederick J; Friedman, Carolyn S

    2006-09-14

    Seed losses of Pacific oysters Crassostrea gigas have been associated with an ostreid herpesvirus-1 (OsHV-1) in Europe, and in 2002, a similar OsHV was detected in Tomales Bay, California, USA. In May of 2003, 5 stocks of seed Pacific oysters were planted at 2 sites (Inner Bay and Outer Bay) in Tomales Bay and monitored for mortality, presence/prevalence of OsHV (using polymerase chain reaction [PCR] and histology), and growth. Temperature (degrees C) and salinity data were collected every half an hour at each site. OsHV was detected at both the Inner and Outer Bay sites on the same sample date and mean temperature predicted OsHV presence (p < 0.005). High levels of mortality occurred 2 wk (Inner Bay site) and 4 wk (Outer Bay site) after OsHV detection. OsHV presence predicted mortality (p = 0.01). Temperature maximums and overall temperature exposure were greater at the Inner Bay site and may explain why mortality affected these oysters sooner than oysters planted at the Outer Bay site. Differences in cumulative mortality were significant among stocks (p < 0.0001), but not between sites (p > 0.05). OsHV prevalence was similar among stocks (p > 0.05) and between sites (p > 0.05). No evidence of herpesvirus-induced Cowdry type A nuclear inclusions or other pathogens were observed. Changes in tissue and cellular architecture including dilation of the digestive tubules and nuclear chromatin margination and pycnosis were observed in OsHV-infected oysters, consistent with previously observed OsHV infections. Stocks with smaller oysters had higher mortality rates than those with larger oysters; growth rate did not correlate with mortalities (p > 0.05). Taken together, these data suggest that the OsHV may cause or act in synergy with temperature to kill Pacific oyster seed in Tomales Bay, but further investigation of OsHV etiology in seed oysters is needed.

  6. 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

  7. 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.

  8. Comparison of metals levels in two mangrove species (Rhizophora stylosa and Sonneratia hainanensis) from Hainan Island, South China

    NASA Astrophysics Data System (ADS)

    Qiu, Y. W.; Qiu, H. L.

    2017-01-01

    Trace metals in mangrove tissues (leaf, branch and root) of two species (Rhizophora stylosa and Sonneratia hainanensis) from Dongzhai Harbor and Sanya Bay of Hainan Island were studied. The total average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in the two mamgrove species were 2.4±1.3, 1.1±0.7, 7.8±8.0, 0.03±0.05, 1.4±1.6, 0.03±0.01 and 0.2±0.2 µg g-1 dw, respectively. Metals concentrations among different tissues of mangroves showed different pattern. In general, Zn, Cd and Hg were slightly enriched in leaf, Cu, Pb and As was enriched in root, and Cr were enriched in branch. Metals levels in R. stylosa and S. hainanensis from both Dongzhai Harbor and Sanya Bay were compared, which suggested that different mangrove species have their unique mechanism to bioaccumulate metals and TOC in the mangrove sediment could be one of the important factors for regulating metals in mangrove tissues. The biota-sediment accumulation factors (BSAF) of metals in mangrove tissues were calculated. The distribution of metals concentrations in mangrove tissues against metals levels in sediment demonstrated that mangrove leaves could be employed as a bio-indicator for some metals (Cu, Zn, Cd and Hg) with temporal monitoring.

  9. 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.

  10. 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).

  11. 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.

  12. Survival of Vibrio vulnificus in shellstock and shucked oysters (Crassostrea gigas and Crassostrea virginica) and effects of isolation medium on recovery.

    PubMed Central

    Kaysner, C A; Tamplin, M L; Wekell, M M; Stott, R F; Colburn, K G

    1989-01-01

    When two species of shellstock oysters were artificially contaminated with Vibrio vulnificus, the bacterium survived when the oysters were stored at 10 degrees C and below. Large numbers of endogenous V. vulnificus cells were found after 7 days at both 0.5 and 10 degrees C in uninoculated control oysters (Crassostrea virginica). Oysters allowed to take up V. vulnificus from seawater retained the bacterium for 14 days at 2 degrees C. The presence of V. vulnificus in the drip exuded from the shellstock presented a possibility of contamination of other shellstock in storage. V. vulnificus injected into shucked Pacific (Crassostrea gigas) and Eastern (C. virginica) oysters survived at 4 degrees C for at least 6 days. An 18-h most-probable-number enrichment step in alkaline peptone water gave higher recovery levels of V. vulnificus than did direct plating to selective agars. The survival of this pathogen in both shellstock and shucked oysters suggests a potential for human illness, even though the product is refrigerated. PMID:2619304

  13. Molecular and histological identification of Marteilioides infection in Suminoe Oyster Crassostrea ariakensis, Manila Clam Ruditapes philippinarum and Pacific Oyster Crassostrea gigas on the south coast of Korea.

    PubMed

    Limpanont, Yanin; Yanin, Limpanont; Kang, Hyun-Sil; Hong, Hyun-Ki; Jeung, Hee-Do; Kim, Bong-Kyu; Le, Thanh Cuong; Kim, Young-Ok; Choi, Kwang-Sik

    2013-11-01

    The oyster ovarian parasite Marteilioides chungmuensis has been reported from Korea and Japan, damaging the oyster industries. Recently, Marteilioides-like organisms have been identified in other commercially important marine bivalves. In this study, we surveyed Marteilioides infection in the Manila clam Ruditapes philippinarum, Suminoe oyster Crassostrea ariakensis, and Pacific oyster Crassostrea gigas, using histology and Marteilioides-specific small subunit (SSU) rDNA PCR. The SSU rDNA sequence of M. chungmuensis (1716 bp) isolated from C. gigas in Tongyoung bay was 99.9% similar to that of M. chungmuensis reported in Japan. Inclusions of multi-nucleated bodies in the oocytes, typical of Marteilioides infection, were identified for the first time in Suminoe oysters. The SSU rDNA sequence of a Marteilioides-like organism isolated from Suminoe oysters was 99.9% similar to that of M. chungmuensis. Marteilioides sp. was also observed from 7 Manila clams of 1840 individuals examined, and the DNA sequences of which were 98.2% similar to the known sequence of M. chungmuensis. Unlike Marteilioides infection of Pacific oysters, no remarkable pathological symptoms, such as large multiple lumps on the mantle, were observed in infected Suminoe oysters or Manila clams. Distribution of the infected Manila clams, Suminoe oysters and Pacific oysters was limited to small bays on the south coast, suggesting that the southern coast is the enzootic area of Marteilioides infection.

  14. 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)

  15. 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

  16. Bioaccumulation of trace metals in farmed pacific oysters Crassostrea gigas from SW Gulf of California coast, Mexico.

    PubMed

    Jonathan, M P; Muñoz-Sevilla, N P; Góngora-Gómez, Andrés Martin; Luna Varela, Raquel Gabriela; Sujitha, S B; Escobedo-Urías, D C; Rodríguez-Espinosa, P F; Campos Villegas, Lorena Elizabeth

    2017-11-01

    The aim of the study was to evaluate the bioavailability of trace metals (Chromium, Copper, Nickel, Lead, Zinc, Cadmium, Arsenic, and Mercury) in the commercially consumed Crassostrea gigas oysters collected over a 12-month growth period (2011-12) from an experimental cultivation farm in La Pitahaya, Sinaloa State, Mexico. Sediment and water samples were also collected from four different zones adjacent to the cultivation area to identify the concentration patterns of metals. The results revealed that sewage disposals, fertilizers used for agricultural practices and shrimp culture are the major sources for the enrichment of certain toxic metals. The metal concentrations in oysters presented a decreasing order of abundance (all values in mg Kg(-1)): Zn (278.91 ± 93.03) > Cu (63.13 ± 31.72) > Cr (22.29 ± 30.23) > Cd (14.54 ± 4.28) > Ni (9.41 ± 11.33) > Pb (2.22 ± 1.33) > As (0.58 ± 0.91) > Hg (0.04 ± 0.06). Bioconcentration Factor (BCF) and Biota Sediment Accumulation Factor (BSAF) exhibited that C. gigas in the region are strong accumulators for Zn and Cd respectively. Thus, the present study proves to fulfill the gap in understanding the rate of bioaccumulation of metals in C. gigas which is regarded as the most sought after oyster species globally. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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.

  18. 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)

  19. Efficacy of Rhizophora mangle aqueous bark extract (RMABE) in the treatment of aphthous ulcers: a pilot study.

    PubMed

    de Armas, Elizabeth; Sarracent, Yamina; Marrero, Eva; Fernández, Octavio; Branford-White, Christopher

    2005-11-01

    Rhizophora mangle aqueous bark extract (RMABE) (CIKRON-H), has been used as antiseptic and skin wound healing promoter. The present study was a randomised, single-blinded, placebo control trial conducted to asses the efficacy of RMABE in treating oral aphthous ulcers. Patients (n = 32) with aphthous ulcers were randomised to received placebo solution or RMABE topically, once a day, from Monday to Friday, until they healed. The efficacy of the treatment was evaluated by physician clinical observations (time to heal, change in condition), the quality of the patient's life and the tolerability through recording adverse effects. No demographic differences were noted between the two groups at base-line. Seven days after treatment, 12 of the 17 patients in the RMABE group (71%) were completely healed of their aphthous ulcers, with repaired mucosa and no symptoms of ulcers, compared with one in 15 patients in the placebo group (7%) (p < 0.0001). The time taken for the signs and symptoms of ulcers to diminish was also higher in the placebo than in RMABE-treatment group (erythema: placebo 10.54 +/- 1.24, RMABE 4.94 +/- 0.72 days, p = 0.0003; ardour: placebo 7.00 +/- 0.76, RMABE 2.93 +/- 0.49 days, p = 0.0001; and pain: placebo 7.43 +/- 1.21, RMABE 2.92 +/- 0.23 days, p = 0.0011). No subject showed any sign of adverse effects. These observations demonstrate that the R. mangle aqueous bark extract reduced the time to repair mucosal tissue, erythema, ardour and pain persistence. There was no evidence any adverse effects. This is the first time that the R. mangle extract has been reported to have mouth mucosa healing properties.

  20. 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.

  1. 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.

  2. Biogenic guaianolide-type sesquiterpene lactones with antioxidative and anti-inflammatory properties from natural mangrove hybrid Rhizophora annamalayana.

    PubMed

    Raola, Vamshi Krishna; Chakraborty, Kajal

    2017-02-24

    Previously undescribed guaianolide-type sesquiterpene lactones were isolated from the chloroform fraction of the natural hybrid mangrove Rhizophora annamalayana, and were characterised as (Z)-3α,4,5,6-tetrahydro-5α-isobutyl-2β-(methoxymethyl)-7-methyl-3H-cyclohepta[b]carbolactone (1) and (7Z)-isopentyl 3α,4,5,6,7,8-hexahydro-2β-((E)-11-methylbut-10-enyl)-1-oxo-2H-cyclohepta[b]furan-6-carboxylate (2). Compound 2 displayed greater antioxidative activities {1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2'-azino-bis-3 ethylbenzothiozoline-6-sulphonic acid diammonium salt (ABTS), IC50 0.65 and 0.62 mg/mL, respectively)} compared to 1 (IC50 0.83 and 1.14 mg/mL, respectively) (p < 0.05). Compound 2 recorded no significant difference in DPPH(.) scavenging activities (IC50 0.65 mg/mL) compared to α-tocopherol (IC50 0.63 mg/mL). Pro-inflammatory 5-lipoxygenase inhibitory activity of 2 was found to be comparable (IC50 0.98 mg/mL) to that displayed by synthetic anti-inflammatory drug ibuprofen (IC50 0.93 mg/mL). Compound 2 showed significantly greater selectivity index (anti-cyclooxygenase-1/anti-cyclooxygenase-2 = 2.15) than non-steroidal anti-inflammatory ibuprofen (<0.5) (p < 0.05), and therefore, might be used as selective cyclooxygenase-2 inhibitor. The hitherto undescribed guaianolide lactones might be used as potential anti-inflammatory and antioxidative pharmacophore leads.

  3. Accumulation profile and seasonal variations of polychlorinated biphenyls (PCBs) in bivalves Crassostrea tulipa (oysters) and Anadara senilis (mussels) at three different aquatic habitats in two seasons in Ghana.

    PubMed

    Dodoo, D K; Essumang, D K; Jonathan, J W A

    2013-02-01

    Research has shown that some polychlorinated biphenyl congeners degrade slowly in the environment and build up in the food chain, causing a wide range of possible adverse effects to humans. In order to ascertain the nature of the situation in Ghana, polychlorinated biphenyls congener residues in Crassostrea tulipa (oysters) and Anadara senilis (mussels) at Narkwa, Ada and Anyanui in the coastal region of Ghana were determined. At Narkwa, both bivalves' species were collected; at Ada only Anadara senilis were collected while at Anyanui, only Crassotrea tulipa were collected. The number of each bivalve species collected from each site was 80 (n=80), making up a total of 320 for the dry and the wet seasons. The PCBs were extracted with (1:1) hexane-acetone mixture and analyzed with a gas chromatogram equipped with (65)Ni electron capture detector, model CP 3800 using the mixed PCBs standard of the ICES 7. Total PCBs in the bivalves ranged from 5.55 to 6.37 μg/kg wet weight in mussels and 2.95-11.41 μg/kg wet weight in oysters, respectively. The composition of the PCB homologues in the bivalves was dominated by tri-, hepta- and hexa-PCBs in descending order. Risk assessments conducted on the samples indicated that edible bivalves from Narkwa, Ada and Anyanui in Ghana might pose some health risk to the consumers. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. 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.

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

    PubMed

    Acosta Ruíz, M J; Gutiérrez Wing, M T

    1996-08-01

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

  6. Leaf morphological strategies of seedlings and saplings of Rhizophora mangle (Rhizophoraceae), Laguncularia racemosa (Combretaceae) and Avicennia schaueriana (Acanthaceae) from Southern Brazil.

    PubMed

    Pelozo, Andressa; Boeger, Maria Regina T; Sereneski-de-Lima, Carolina; Soffiatti, Patricia

    2016-03-01

    The initial phase of a plant life cycle is a short and critical period, when individuals are more vulnerable to environmental factors. The morphological and anatomical study of seedlings and saplings leaf type enables the understanding of species strategies of fundamental importance in their establishment and survival. The objective of this study was to analyze the structure of seedlings and saplings leaf types of three mangrove species, Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, to understand their early life adaptive strategies to the environment. A total of 30 fully expanded cotyledons (A. schaueriana and L. racemosa), 30 leaves of seedlings, and 30 leaves of saplings of each species were collected from a mangrove area in Guaratuba Bay, Paraná State, Brazil. Following standard methods, samples were prepared for morphological (leaf dry mass, density, thickness) and anatomical analysis (epidermis and sub-epidermal layers, stomata types, density of salt secretion glands, palisade and spongy parenchyma thickness). To compare leaf types among species one-way ANOVA and Principal Component Analysis were used, while Cluster Analysis evaluated differences between the species. We observed significant structural differences among species leaf types. A. schaueriana showed the thickest cotyledons, while L. racemosa presented a dorsiventral structure. Higher values of the specific leaf area were observed for seedlings leaves of A. schaueriana, cotyledons of L. racemosa and saplings leaves of A. schaueriana and R. mangle. Leaf density was similar to cotyledons and seedlings leaves in A. schaueriana and L. racemosa, while R. mangle had seedlings leaves denser than saplings. A. schaueriana and R. mangle showed hypostomatic leaves, while L. racemosa amphistomatic; besides, A. chaueriana showed diacytic stomata, while L. racemosa anomocytic, and R. mangle ciclocytic. Seedling leaves were thicker in R. mangle (535 μm) and L. racemosa (520 μm) than in A

  7. Comparative phylogeography of black mangroves (Avicennia germinans) and red mangroves (Rhizophora mangle) in Florida: Testing the maritime discontinuity in coastal plants.

    PubMed

    Hodel, Richard G J; Cortez, Maria B de Souza; Soltis, Pamela S; Soltis, Douglas E

    2016-04-01

    Previous studies of the comparative phylogeography of coastal and marine species in the southeastern United States revealed that phylogenetically diverse taxa share a phylogeographic break at the southern tip of Florida (the maritime discontinuity). These studies have focused nearly exclusively on animals; few coastal plant species in Florida have been analyzed phylogeographically. We investigated phylogeographic patterns of black mangroves (Avicennia germinans) and red mangroves (Rhizophora mangle), two coastal trees that occur on both coasts of the peninsula of Florida. We sampled and genotyped 150 individuals each of A. germinans and R. mangle, using eight microsatellite loci per species. We used observed and expected heterozygosity to quantify genetic diversity in each sampling location and allele frequencies to identify putative phylogeographic breaks and measure gene flow using BayesAss and Migrate-n. We tested the hypothesis that both species would exhibit a phylogeographic break at the southern tip of Florida. We did not find any significant phylogeographic breaks in either species. Rhizophora mangle exhibits greater genetic structure than A. germinans, contrary to expectations based on propagule dispersal capability. However, directional gene flow from the Gulf to the Atlantic was more pronounced in R. mangle, indicating that the Gulf Stream may affect genetic patterns in R. mangle more than in A. germinans. The high dispersal capability of these species may lead to high genetic connectivity between sampling locations and little geographic structure. We also identified several locations that, based on genetic data, should be the focus of conservation efforts. © 2016 Botanical Society of America.

  8. 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.

  9. Greater hemocyte bactericidal activity in oysters (Crassostrea virginica) from a relatively contaminated site in Pensacola Bay, Florida.

    PubMed

    Oliver, Leah M; Fisher, William S; Volety, Aswani K; Malaeb, Ziad

    2003-09-10

    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 accumulation in both experimental and long-term field exposures. In an effort to elucidate these relationships, 40 oysters were collected from Bayou Chico (BC) and East Bay (EB) in Pensacola Bay, FL, two estuaries known to differ in the type and magnitude of chemical contaminants present. Oyster tissue concentrations of metals, tri- and dibutyltin (TBT, DBT), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in individual oysters, as were hemocyte counts (HCs), hemocyte bacterial killing indices (KI), serum lysozyme (LYS) and serum protein (PRO) levels. Average HC, KI, LYS and PRO were significantly higher in BC oysters, which also had significantly higher tissue concentrations of total trace metals, butyltins (BTs), PAHs, PCBs, pesticides, and Mn, Cu, Zn and Sn. EB oysters had low organic contaminant levels and no detectable BTs, but significantly higher concentrations of Al, Cr, Fe, Ag, Cd, and Hg. Simple correlation analysis between specific defense measurements and specific chemical analytes showed specific positive relationships that corroborated previous findings in other FL estuaries. Canonical correlation analysis was used to examine relationships between defense measurements and tissue metals using linearly combined sets of variables. Results were also consistent with previous findings-the highest possible canonical correlation was positive: r=0.864, P<0.0019 among canonical variables composed of HC, KI and LYS for defense, and Fe, Cu, Ag, Cd, Sb, Sn, Ni, Pb and Hg for metals.

  10. 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...

  11. 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...

  12. 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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  14. 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...

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  16. 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...

  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. Comparative study of three C1q domain containing proteins from pacific oyster Crassostrea gigas.

    PubMed

    Lv, Zhao; Qiu, Limei; Wang, Mengqiang; Jia, Zhihao; Wang, Weilin; Xin, Lusheng; Liu, Zhaoqun; Wang, Lingling; Song, Linsheng

    2017-09-18

    C1q domain containing proteins (C1qDCs) are a family of proteins containing a globular head C1q domain (ghC1q) in C-terminus, which serve as pattern recognition receptors (PRRs) and mediate a series of immune responses. In the present study, three C1qDC proteins from pacific oyster Crassostrea gigas (CgC1qDC-2, CgC1qDC-3, CgC1qDC-4) were characterized and comparatively investigated to understand their roles in the immune response. All the three recombinant CgC1qDC proteins (rCgC1qDCs) could bind lipopolysaccharide (LPS) significantly but they could not bind lipoteichoic acid (LTA), β-1,3-glucan (GLU), mannan (MAN), and polyinosinic-polycytidylic acid (Poly I:C). Correspondingly, they all exhibited higher binding activities towards Gram-negative bacteria Vibrio anguillarum and V. splendidus. Moreover, they could enhance the phagocytosis of oyster hemocytes, and the enhancements towards Gram-negative bacteria were significantly higher than that towards Gram-positive bacteria (p < 0.01). The LPS binding affinity of rCgC1qDC-3 (KD = 8.74 × 10(-7) M) was higher than that of rCgC1qDC-2 (KD = 7.76 × 10(-5) M) and rCgC1qDC-4 (KD = 1.09 × 10(-5) M). Meanwhile, rCgC1qDC-3 exhibited significantly higher enhancement on phagocytosis of oyster hemocytes towards Gram-negative bacteria than that of rCgC1qDC-2 and rCgC1qDC-4 (p < 0.05). After the secondary challenge with V. splendidus, the up-regulations of CgC1qDC-2 and CgC1qDC-4 mRNA in hemocytes occurred at 6 h, while that of CgC1qDC-3 was observed at 3 h and lasted for 24 h. And CgC1qDC-3 responded with high mRNA level for tested 24 h upon the secondary challenge with V. anguillarum as well. These results collectively suggested that three CgC1qDCs could serve as PRRs to specifically recognize certain Gram-negative bacteria and opsonins to enhance phagocytosis. CgC1qDC-3, with higher binding affinity to LPS, stronger opsonization and more rapid and persistent mRNA expression response upon the secondary

  19. Detection and description of a particular Ostreid herpesvirus 1 genotype associated with massive mortality outbreaks of Pacific oysters, Crassostrea gigas, in France in 2008.

    PubMed

    Segarra, Amélie; Pépin, Jean François; Arzul, Isabelle; Morga, Benjamin; Faury, Nicole; Renault, Tristan

    2010-10-01

    Ostreid herpesvirus 1 (OsHV-1) infections have been reported around the world and are associated with high mortalities of the Pacific oyster (Crassostrea gigas). In the summer 2008, abnormal mortality rates ranging from 80% to 100% were reported in France and affected only Pacific oysters. Analyses of oyster samples collected during mortality outbreaks demonstrated a significant detection of OsHV-1 (75% of analysed batches), which appeared stronger than previous years. DNA sequencing based on C and IA regions was carried out on 28 batches of OsHV-1 infected Pacific oysters collected in 2008. Polymorphisms were described in both the C and IA regions and characterized a genotype of OsHV-1 not already reported and termed OsHV-1 microVar. A microsatellite zone present in the C region showed several deletions. Additionally, 44 isolates collected in France and in the USA, from 1995 to 2007 were sequenced and compared to the 2008 sequences. The analyses of 76 sequences showed OsHV-1 microVar detection only in 2008 isolates. These data suggest that OsHV-1 microVar can be assumed as an emergent genotype.

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

    PubMed

    Patil, Jawahar G; Gunasekera, Rasanthi M; Deagle, Bruce E; Bax, Nicholas J

    2005-01-01

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

  1. Vibrio crassostreae, a benign oyster colonizer turned into a pathogen after plasmid acquisition.

    PubMed

    Bruto, Maxime; James, Adèle; Petton, Bruno; Labreuche, Yannick; Chenivesse, Sabine; Alunno-Bruscia, Marianne; Polz, Martin F; Le Roux, Frédérique

    2016-12-06

    Vibrios are frequently associated with oyster mortality; however whether they are the primary causative agent or secondary opportunistic colonizers is not well understood. Here we combine analysis of natural infection dynamics, population genomics and molecular genetics to ask (i) to what extent oysters are passively colonized by Vibrio population present in the surrounding water, (ii) how populations turn over during pathogenicity events and (iii) what genetic factors are responsible for pathogenicity. We identified several populations of Vibrio preferentially associated with oyster tissues. Among these, Vibrio crassostreae is particularly abundant in diseased animals while nearly absent in the surrounding water, and its pathogenicity is correlated with the presence of a large mobilizable plasmid. We further demonstrate that the plasmid is essential for killing but not necessary for survival in tissues of oysters. Our results suggest that V. crassostreae first differentiated into a benign oyster colonizer that was secondarily turned into a pathogen by introgression of a virulence plasmid into the population, possibly facilitated by elevated host density in farming areas.The ISME Journal advance online publication, 6 December 2016; doi:10.1038/ismej.2016.162.

  2. Genetic and evolutionary patterns of innate immune genes in the Pacific oyster Crassostrea gigas.

    PubMed

    Song, Kai; Li, Yingxiang; Huang, Baoyu; Li, Li; Zhang, Guofan

    2017-12-01

    The invertebrate innate immune system functions in immune defence and the stress response. However, knowledge of the genetic and evolutionary patterns of innate immune genes in Mollusca is limited, especially for oysters. Such information would help clarify how oysters adapt to pathogen-rich environments. Here, we characterized the genetic and evolutionary patterns of the innate immune genes in Crassostrea gigas, using population diversity analysis and evolution rates comparison. Innate immune genes have higher median nucleotide diversity than non-immune genes. Nucleotide diversity varied with functional regions and different immune-related gene families. Evolutionary analysis of two Crassostrea species showed that the innate immune genes are less conserved and have higher rates of evolution in C. gigas. We also noted a positive association between nucleotide diversity and selective pressures for genes having orthologues. Our findings will help determine the evolutionary patterns of innate immune genes and the association of these genes with mollusc immunity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Streptomyces effect on the bacterial microbiota associated to Crassostrea sikamea oyster.

    PubMed

    García Bernal, M; Trabal Fernández, N; Saucedo Lastra, P E; Medina Marrero, R; Mazón-Suástegui, J M

    2017-03-01

    To determine the composition and diversity of the microbiota associated to Crassostrea sikamea treated during 30 days with Streptomyces strains N7 and RL8. DNA was extracted from oysters followed by 16S rRNA gene amplification and pyrosequencing. The highest and lowest species diversity richness was observed in the initial and final control group, whereas Streptomyces-treated oysters exhibited intermediate values. Proteobacteria was the most abundant phylum (81·4-95·1%), followed by Bacteroidetes, Actinobacteria and Firmicutes. The genera Anderseniella, Oceanicola, Roseovarius, Ruegeria, Sulfitobacter, Granulosicoccus and Marinicella encompassed the core microbiota of all experimental groups. The genus Bacteriovorax was detected in all groups except in the final control and the depurated N7, whereas Vibrio remained undetected in all Streptomyces-treated groups. RL8 was the only group that harboured the genus Streptomyces in its microbiota. Principal component analysis showed that Streptomyces strains significantly changed oyster microbiota with respect to the initial and final control. Crassostrea sikamea treated with Streptomyces showed high species diversity and a microbiota composition shift, characterized by keeping the predator genus Bacteriovorax and decreasing the pathogenic Vibrio. This is the first culture-independent study showing the effect of Streptomyces over the oyster microbiota. It also sheds light about the potential use of Streptomyces to improve mollusc health and safety for consumers after the depuration process. © 2016 The Society for Applied Microbiology.

  4. 4-Phenyl-3,4-dihydroquinolone derivatives from Aspergillus nidulans MA-143, an endophytic fungus isolated from the mangrove plant Rhizophora stylosa.

    PubMed

    An, Chun-Yan; Li, Xiao-Ming; Luo, Han; Li, Chun-Shun; Wang, Ming-Hui; Xu, Gang-Ming; Wang, Bin-Gui

    2013-10-25

    Six new 4-phenyl-3,4-dihydroquinolone derivatives (1-6) along with the related aflaquinolone A (7) were isolated and identified from the cultures of Aspergillus nidulans MA-143, an endophytic fungus obtained from the fresh leaves of the marine mangrove plant Rhizophora stylosa. Their structures including absolute configurations were determined by spectroscopic analysis and electronic circular dichroism experiments, and the structure of compound 1 was confirmed by single-crystal X-ray crystallographic analysis. In bioscreening experiments, none of the isolated compounds showed potent antibacterial or cytotoxic activity. However, compounds 2, 3, and 7 exhibited lethality against brine shrimp (Artemia salina), with LD50 values of 7.1, 4.5, and 5.5 μM, respectively.

  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. 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

  7. 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

  8. A comparative proteomic study on the effects of metal pollution in oysters Crassostrea hongkongensis.

    PubMed

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

    2016-11-15

    The metal pollution has posed great risk on the coastal organisms along the Jiulongjiang Estuary in South China. In this work, two-dimensional electrophoresis-based proteomics was applied to the oysters Crassostrea hongkongensis from metal pollution sites to characterize the proteomic responses to metal pollution. Metal accumulation and proteomic responses indicated that the oysters from BJ site were more severely contaminated than those from FG site. Compared with those oyster samples from the clean site (JZ), metal pollution induced cellular injuries, oxidative and immune stresses in oyster heapatopancreas from both BJ and FG sites via differential metabolic pathways. In addition, metal pollution in BJ site induced disturbance in energy and lipid metabolisms in oysters. Results indicated that cathepsin L and ferritin GF1 might be the biomarkers of As and Fe in oyster C. hongkongensis, respectively. This study demonstrates that proteomics is a useful tool for investigating biological effects induced by metal pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Impact of diuron on aneuploidy and hemocyte parameters in Pacific oyster, Crassostrea gigas.

    PubMed

    Bouilly, Karine; Bonnard, Marc; Gagnaire, Béatrice; Renault, Tristan; Lapègue, Sylvie

    2007-01-01

    Diuron is a substituted urea herbicide used for agricultural and nonagricultural weed control. Its widespread use and relatively slow breakdown led us to analyze its influence on aneuploidy level (lowered chromosome number in a percentage of somatic cells) and hemocyte parameters in Pacific oysters, Crassostrea gigas. Adult oysters were subjected to two diuron concentrations (300 ng L(-1) and 3 microg L(-1)) for 11 weeks. Significantly higher aneuploidy level was observed in diuron-treated oysters compared with the control. Furthermore, the observed impact on aneuploidy persisted to the next generation as offspring exhibited significantly higher aneuploidy levels when their parents had been exposed to diuron. Significant increases in hemocyte parameters (cell mortality, phagocytosis, granulocyte percentage, reactive oxygen species, and lysosome presence) of the adults were also observed after 4 weeks of diuron exposure. The effects observed on oyster aneuploidy level and hemocyte parameters could have serious environmental and practical consequences.

  10. Genome-wide profiling of DNA methylation and gene expression in Crassostrea gigas male gametes

    PubMed Central

    Olson, Claire E.; Roberts, Steven B.

    2014-01-01

    DNA methylation patterns and functions are variable across invertebrate taxa. In order to provide a better understanding of DNA methylation in the Pacific oyster (Crassostrea gigas), we characterized the genome-wide DNA methylation profile in male gamete cells using whole-genome bisulfite sequencing. RNA-Seq analysis was performed to examine the relationship between DNA methylation and transcript expression. Methylation status of over 7.6 million CpG dinucleotides was described with a majority of methylated regions occurring among intragenic regions. Overall, 15% of the CpG dinucleotides were determined to be methylated and the mitochondrial genome lacked DNA methylation. Integrative analysis of DNA methylation and RNA-Seq data revealed a positive association between methylation status, both in gene bodies and putative promoter regions, and expression. This study provides a comprehensive characterization of the distribution of DNA methylation in the oyster male gamete tissue and suggests that DNA methylation is involved in gene regulatory activity. PMID:24987376

  11. Aroma extracts from oyster Crassostrea gigas: comparison of two extraction methods.

    PubMed

    Pennarun, Anne-Laure; Prost, Carole; Demaimay, Michel

    2002-01-16

    The study of the aroma of oysters is of great economic interest in France because it enables their organoleptic quality to be verified. The aim of this study is to optimize the extraction methods of the volatile compounds of oysters Crassostrea gigas in order to obtain an extract with an odor as close as possible to that of the original oysters'. Oyster aroma is rarely studied, and its sensory profile has not been investigated to date. Two extraction methods were studied: vacuum hydrodistillation carried out at 20 degrees C with noncrushed oyster using ultrapure water and dynamic headspace carried out using noncrushed oyster during a 30 min purge. They were compared with regard to their sensory characteristics by a panel of seven judges, all trained in seafood aroma recognition. This study has shown that vacuum hydrodistillation is the better method to obtain an extract closest in aroma to the oyster reference.

  12. Evidence of vertical transmission of ostreid herpesvirus 1 in the Portuguese oyster Crassostrea angulata.

    PubMed

    López Sanmartín, Monserrat; Power, Deborah M; de la Herrán, Roberto; Navas, José I; Batista, Frederico M

    2016-10-01

    In order to determine if ostreid herpesvirus 1 (OsHV-1) can be vertically transmitted, 9 full-sib families of the Portuguese oyster Crassostrea angulata were produced using a factorial mating design with 3 males and 3 females. The parents were survivors from an OsHV-1 mortality outbreak. OsHV-1 DNA was not detected by conventional PCR in the mantle of parents, gametes or 3day-old larvae. However, viral DNA was detected by real-time PCR in all gametes and larvae samples. These results show that C. angulata that have survived an OsHV-1 mortality outbreak can carry the virus and vertically transmit it to their offspring.

  13. 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.

  14. 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.

  15. Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

    PubMed

    Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

    2014-07-23

    Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

  16. Crassostrea gigas oysters as a shrimp farm bioindicator of white spot syndrome virus.

    PubMed

    Vazquez-Boucard, C; Escobedo-Fregoso, C; Duran-Avelar, Ma de J; Mercier, L; Llera-Herrera, R; Escobedo-Bonilla, C; Vibanco-Perez, N

    2012-04-26

    This study explored whether Crassostrea gigas oysters can be used as a bioindicator of white spot syndrome virus (WSSV) in shrimp farm water canals. Bioassays showed that C. gigas can accumulate WSSV in their gills and digestive glands but do not become infected, either by exposure to seawater containing WSSV or by cohabitation with infected shrimp. The use of a WSSV nested PCR to screen oysters placed in water canals at the entry of a shrimp farm allowed WSSV to be detected 16 d prior to the disease occurring. The finding that C. gigas can concentrate small amounts of WSSV present in seawater without being harmed makes it an ideal sentinel species at shrimp farms.

  17. 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

  18. 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.

  19. A glycoprotein in shells of conspecifics induces larval settlement of the Pacific oyster Crassostrea gigas.

    PubMed

    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.

  20. [Purification function and ecological services value of Crassostrea sp. in Yangtze River estuary].

    PubMed

    Quan, Wei-Min; Zhang, Jin-Ping; Ping, Xian-Yin; Shi, Li-Yan; Li, Pei-Jun; Chen, Ya-Qu

    2007-04-01

    Oyster reef ecosystem is a natural decontamination plant of estuarine environment. This paper analyzed the bioaccumulation of heavy metals by Crassostrea sp. population at the dams of Yangtze River estuary, with its purification capacity and ecological services value assessed. The results indicated that Crassostrea sp. had a high capacity in bio-accumulating Cu, Zn and Cd, with the bio-concentration factor (BCF) and biota-sediment accumulation factor (BSAF) being (14.28 +/- 2.41) x 10(3), (12.75 +/- 2.02) x 10(3) and (14.51 +/- 3.71) x 10(3), and 26.78 +/- 4.53, 23.24 +/- 3.69 and 16.62 +/- 4.25, respectively. The bioaccumulation capacity decreased in the order of Cu > Zn > Cd > As > Pb > Hg. The total weight and fresh meat weight of the oyster at the dams of Yangtze River estuary were about 1.07 x 10(6) t and 1.75 x 10(5) t, respectively, and the total storage of nutrients and heavy metals were 1.462 x 10(6) kg N, 1 x 10(5) kg P, 24 745 kg Cu, 58 257 kg Zn, 609 kg Pb, 254 kg Cd, 0.18 kg Hg and 329 kg As. The total ecological services value of the oyster reef was estimated at about 8.27 x 10(6) RMB x a(-1), including habitat value of about 5.10 x 10(6) RMB x a(-1) and environmental value of about 3.17 x 10(6) RMB x a(-1). Such an environmental value was equivalent to the value of treating about 7.31 x 10(6) t combined sewage each year, and corresponded to a large municipal sewage plant with a treatment capacity about 20 000 t d(-1).

  1. 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

  2. Proteomic identification of protein associated to mature spermatozoa in the Pacific oyster Crassostrea gigas.

    PubMed

    Kingtong, Sutin; Kellner, Kristell; Bernay, Benoît; Goux, Didier; Sourdaine, Pascal; Berthelin, Clothilde Heude

    2013-04-26

    Knowledge of sperm maturation process is limited in the Pacific oyster Crassostrea gigas and major factors of fertilization success of this free spawning animal are unknown. We investigated proteins associated to spermatozoa by analyzing two cellular fractions obtained from a 40-80% Percoll gradient fractioning of germ cell of mature male gonads. Mature spermatozoa were enriched in the lower Percoll fraction while the upper fraction contained less mature or earlier germ cells. A 2-DE proteomic approach was used to identify differentially expressed proteins in both fractions. We screened out 31 differential proteins (P<0.05) which included 14 up-regulated and 17 down-regulated proteins. Using MALDI-TOF/TOF MS and bioinformatics search against a C. gigas database, 13 and 8 proteins were identified for the up-regulated and down-regulated groups, respectively. In the spermatozoa enriched fraction, proteins regarding flagellum formation and control, energy production and Proteosome subunit beta were increased. In less mature germ cell fraction, proteins regarding developmental processes and chaperon molecules were mainly increased. Our results improve current knowledge of proteins associated with spermatozoa maturation related to zootechnical practices used in mollusk hatcheries. This is the revised version of the manuscript "Proteomic identification of protein associated to mature spermatozoa in the Pacific oyster Crassostrea gigas" by Kingtong et al. to the Journal of Proteomics. The corrections have been done by the team carefully. This work highlight the enrichment method of spermatozoa of Pacific oyster from stripped complex sample using Percoll gradient. The results reflexed developmental stages of germ cells in gonadal tubules of this species. We have used proteomic approach to identify differentially expressed proteins in mature spermatozoa fraction compared to less mature spermatozoa fraction which provided candidates of protein associated to mature spermatozoa

  3. Antioxidant responses in gills and digestive gland of oyster Crassostrea madrasensis (Preston) under lead exposure.

    PubMed

    Shenai-Tirodkar, Prachi S; Gauns, Mangesh U; Mujawar, Mohammad Wassim A; Ansari, Zakir A

    2017-08-01

    Crassostrea are ecologically and economically important bivalves and provide a good livelihood for coastal regions of many countries, including India. This study aims at evaluating the response of the antioxidant defense system in oyster Crassostrea madrasensis against lead (Pb) exposure under laboratory conditions. Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST) and oxidative damage parameter lipid peroxidation (LPO) were measured in the gills and digestive glands of oysters exposed to 1-50µg/l of Pb (NO3)2 over a period of 8 days. LPO index increased progressively with increase in Pb concentration (1, 10, 25 and 50µg/l) in both tissues, gills and digestive gland. Although CAT and SOD activities induced together in the initial phase (upto 6th day), their activities decreased at a later stage of the experiment. However, GST activity increased on 8th day in both the tissues at concentration 10, 25 and 50µg/l indicates the compensatory defense mechanism against oxidative stress. The induced antioxidant responses recorded at 25 and 50µg/l of Pb concentrations suggest the presence of Pb-induced oxidative stress at these concentrations. The results of this work also indicate that LPO, SOD, and GST could be used as biomarkers to assess the impact of Pb on the C. madrasensis. This study concludes that any high level of dissolved Pb concentration (>10µg/l) in surrounding seawater could be harmful to the physiology of the C. madrasensis. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Isotopic Determination of Food Sources of Crassostrea gigasAlong a Trophic Gradient in the Estuarine Bay of Marennes-Ol éron

    NASA Astrophysics Data System (ADS)

    Riera, P.; Richard, P.

    1996-03-01

    Along a trophic gradient from the head of an estuary to the open ocean, carbon isotope ratios were determined both in tissues of the Pacific oyster Crassostrea gigasand in different components of the oysters ' potential food resource. In the study area, the Marennes-Ol éron Bay (France), a gradient in δ 13C occurred in the particulate organic carbon (POC) from riverine ( -29 ·2 - -27 ·4 ‰) to open sea littoral ( -21 ·8 - -19 ·5 ‰). Isotope composition of oysters collected along this estuarine gradient followed a similar trend, indicating a predominant contribution of organic matter derived from terrestrial detritus to the diet of C. gigasinhabiting the upper estuarine reaches. A remarkable departure from this general pattern was noted in the isotope composition of oysters sampled from a reef, at the mouth of the Charente river. These oysters exhibited enriched 13C composition, suggesting that they were largely feeding upon benthic microalgae ( -16 ‰) from an adjacent wide mudflat. The reported results suggest that C. gigasis able to preferentially ingest and/or assimilate particular food sources (i.e. benthic diatoms) among diverse sources within the total organic matter pool.

  5. A previously undescribed ostreid herpes virus 1 (OsHV-1) genotype detected in the pacific oyster, Crassostrea gigas, in Ireland.

    PubMed

    Lynch, S A; Carlsson, J; Reilly, A O; Cotter, E; Culloty, S C

    2012-10-01

    Significant mortalities of the Pacific oyster, Crassostrea gigas, have been reported worldwide since the 1950s. The impact these re-occurring mortality events have had on the C. gigas industry has highlighted the necessity to determine the factors that may be causing these mortalities. This study investigated the possible role of ostreid herpes virus (OsHV-1) in C. gigas mortalities over 2 successive summers at 2 study areas in Ireland. A single sample of adult C. gigas, which had been experiencing mortalities at one of the sites was screened. Successive cohorts of C. gigas spat obtained from a hatchery outside Ireland was relayed to both sites in 2003 and in 2004. Spat were screened each year prior to relaying. Samples were collected every 2 weeks and mortality counts were recorded and observed at both sites. Polymerase chain reaction (PCR) analysis and subsequent sequencing indicated that a previously undocumented variant genotype of OsHV-1 was present in the single cohort of adult C. gigas and in seed and juveniles at both sites, in both years. Analysis suggests that the Irish OsHV-1 μvar variant genotype is closely related to OsHV-1 μvar, first described in France in 2008.

  6. Ostreid herpesvirus OsHV-1 μVar in Pacific oysters Crassostrea gigas (Thunberg 1793) of the Wadden Sea, a UNESCO world heritage site.

    PubMed

    Gittenberger, A; Voorbergen-Laarman, M A; Engelsma, M Y

    2016-01-01

    The Wadden Sea is an extensive wetland area, recognized as UNESCO world heritage site of international importance. Since the mid-1990s, the invasive Pacific oyster Crassostrea gigas (Thunberg 1793) population in the area has grown exponentially, having a distinct impact on the ecosystem. The recent spread of the emerging oyster pathogen Ostreid herpesvirus OsHV-1 μVar worldwide and specifically in the oyster culture areas in the south of the Netherlands raised the question whether the virus may also be present in the Wadden Sea. In the summer of 2012 juvenile Pacific oysters were collected from five locations in the Dutch Wadden Sea. The virus was shown to be present in three of the five locations by real-time PCR and sequencing. It was concluded that OsHV-1 μVar has settled itself in Pacific oyster reefs in the Wadden Sea. These results and the recent discoveries of OsHV-1 microvariants in Australia and Korea indicate that OsHV-1 μVar and related variants might be more widespread than can be deduced from current literature. In particular in regions with no commercial oyster culture, similar to the Wadden Sea, the virus may go undetected as wild beds with mixed age classes hamper the detection of mortality among juvenile oysters.

  7. 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.

  8. Impact of Environment and Ontogeny on Relative Fecundity and Egg Quality of Female Oysters (Crassostrea virginica) from Four Sites in Northern Chesapeake Bay.

    PubMed

    Glandon, Hillary Lane; Michaelis, Adriane K; Politano, Vincent A; Alexander, Stephanie T; Vlahovich, Emily A; Reece, Kimberly S; Koopman, Heather N; Meritt, Donald W; Paynter, Kennedy T

    2016-12-01

    Resource allocation to reproduction is a primary physiological concern for individuals, and can vary with age, environment, or a combination of both factors. In this study we quantified the impact of environment and individual age on the reproductive output of female oysters Crassostrea virginica. We determined the relative fecundity, egg total lipid content, and overall and omega-3/omega-6 (ω3/ω6) fatty acid signatures (FAS) of eggs spawned by female oysters over a 2-year period (n = 32 and n = 64). Variation was quantified spatially and ontogenetically by sampling young and old oyster populations from two rivers in Chesapeake Bay, totaling four collection sites. During Year 1, when oysters underwent oogenesis in different locations, overall and ω3/ω6 egg FAS varied significantly by river, with no significant differences observed in the FAS of oysters by age in Year 1. In Year 2, when oysters from different sites underwent oogenesis in a single location, no significant differences in the overall egg FAS or ω3/ω6 egg FAS by river or age were observed. These findings suggest that oysters integrate environment into their reproductive output, but that time spent growing at a specific location (in this case, represented by oyster age) plays a relatively minor role in the biochemical composition of oyster eggs. These results have consequences for our understanding of how resources are allocated from the female oyster to eggs and, more generally, the impact of environment and ontogeny on reproductive physiology.

  9. 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.

  10. Transcriptomic analysis of oyster Crassostrea gigas larvae illustrates the response patterns regulated by catecholaminergic system upon acute heat and bacterial stress.

    PubMed

    Liu, Zhaoqun; Wang, Lingling; Zhou, Zhi; Liu, Yu; Dong, Miren; Wang, Weilin; Song, Xiaorui; Wang, Mengqiang; Gao, Qiang; Song, Linsheng

    2017-03-07

    Bacterial infection and heat stress, as two major environmental threats of marine molluscs, could affect larval development and dramatically promote mortality of oysters. In the present study, next-generation sequencing, together with determinations of mRNA expression and measurements of enzyme activities, were employed to understand the response patterns of oyster larvae under acute heat and bacterial stress. After RNA-seq, a total of 9472 differentially expressed genes including 4895 significantly up-regulated ones and 4577 significantly down-regulated ones were obtained from 12 transcriptome libraries. GO overrepresentation analysis of the up-regulated genes revealed that the neuroendocrine immunomodulation pathway was activated after acute heat and bacterial stimulation, in which the catecholaminergic regulation played an important role. GO overrepresentation analysis of the down-regulated genes suggested that the immune capacity of Crassostrea gigas larvae was suppressed under stress, which was further validated since superoxide dismutase (SOD) and phenoloxidase (PO) activities in the total protein extract of larvae decreased dramatically after stress. Moreover, the shell formation of trochophore was inhibited and severe mortality was caused after acute heat and bacterial stress. These results collectively indicated that acute heat and bacterial stress could significantly inhibit larval development and suppress immune response of oyster C. gigas larvae. And the neuroendocrine immunomodulation, especially the catecholaminergic regulation, played an indispensable role in the stress response of molluscan larvae.

  11. Hemocyte parameters of the Pacific oyster Crassostrea gigas a year after the Hebei Spirit oil spill off the west coast of Korea

    NASA Astrophysics Data System (ADS)

    Donaghy, Ludovic; Hong, Hyun-Ki; Lee, Hee-Jung; Jun, Je-Cheon; Park, Young-Je; Choi, Kwang-Sik

    2010-12-01

    In marine bivalves, hemocytes support various physiological functions, including immune defense, nutrient transport, shell repair, and homeostatic maintenance. Although the effects of marine contaminants on the immunological functions of bivalves have been extensively investigated, the impacts of oil spills are not well understood. Therefore, we investigated hemocyte parameters in the Pacific oyster Crassostrea gigas 13 months after the Hebei Spirit oil spill (December 2007) off the west coast of Korea. The parameters studied included hemocyte concentration and mortality, relative proportion of hemocyte populations, and immunological functions such as phagocytosis and oxidative activity using flow cytometry. These immune-related parameters in oysters damaged by the oil spill were also compared to control oysters that were collected from an area unaffected by the spill. The flow cytometry study indicated that granulocyte population, phagocytic capacity, and reactive oxygen species production in oysters exposed to crude oil 13 months prior were depressed compared to the unexposed control oysters. Our data suggest that immunocompetence in oysters affected by the oil spill had not fully recovered 1 year after the accident, although more detailed studies on the physiology and disease resistance should be performed.

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

    PubMed

    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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Investigation of mass attenuation coefficient of almond gum bonded Rhizophora spp. particleboard as equivalent human tissue using XRF technique in the 16.6-25.3 keV photon energy.

    PubMed

    Ababneh, Baker; Tajuddin, Abd Aziz; Hashim, Rokiah; Shuaib, Ibrahim Lutfi

    2016-12-01

    This paper reports the novel use of almond gum as a binder in manufacturing Rhizophora spp. particleboard. X-ray fluorescence spectroscopy was employed for analysis under photon energy range of 16.6-25.3 keV. Results showed that almond gum-bonded Rhizophora spp. particleboard can be used as tissue-equivalent phantom in diagnostic radiation. The calculated mass attenuation coefficients of the particleboards were consistent with the values of water calculated using XCOM program for the same photon energies, with p values of 0.056, 0.069, and 0.077 for samples A8, C0, and C8, respectively. However, no direct relationship was found between the percentage of adhesive and the mass attenuation coefficient. The results positively supported the use of almond gum as a binding agent in the fabrication of particleboards, which can be used as a phantom material in dosimetric and quality control applications.

  20. The specifically enhanced cellular immune responses in Pacific oyster (Crassostrea gigas) against secondary challenge with Vibrio splendidus.

    PubMed

    Zhang, Tao; Qiu, Limei; Sun, Zhibin; Wang, Lingling; Zhou, Zhi; Liu, Rui; Yue, Feng; Sun, Rui; Song, Linsheng

    2014-07-01

    The increasing experimental evidences suggest that there are some forms of specific acquired immunity in invertebrates, but the underlying mechanism is not fully understood. In the present study, Pacific oyster (Crassostrea gigas) stimulated primarily by heat-killed Vibrio splendidus displayed stronger immune responses at cellular and molecular levels when they encountered the secondary challenge of live V. splendidus. The total hemocyte counts (THC) increased significantly after the primary stimulation of heat-killed V. splendidus, and it increased even higher (p < 0.01) and reached the peak earlier (at 6 h) after the secondary challenge with live V. splendidus compared with that of the primary stimulation. The number of new generated circulating hemocytes increased dramatically (p < 0.01) at 6 h after the pre-stimulated oysters received the secondary stimulation with live V. splendidus, and the phagocytic rate was also enhanced significantly (p < 0.01) at 12 h after the secondary stimulation. Meanwhile, the enhanced phagocytosis of hemocytes was highly specific for V. splendidus and they could distinguish Vibrio anguillarum, Vibrio coralliilyticus, Yarrowia lipolytica, and Micrococcus luteus efficiently. In addition, the mRNA expression of 12 candidate genes related to phagocytosis and hematopoiesis were also monitored, and the expression levels of CgIntegrin, CgPI3K (phosphatidylinositol 3-kinase), CgRho J, CgMAPKK (mitogen-activated protein kinase kinase), CgRab32, CgNADPH (nicotinamide adenine dinucleotide phosphate) oxidase, CgRunx1 and CgBMP7 (bone morphogenetic protein 7) in the hemocytes of pre-stimulated oysters after the secondary stimulation of V. splendidus were higher (p < 0.01) than that after the primary stimulation, but there was no statistically significant changes for the genes of CgPKC (protein kinase C), CgMyosin, CgActin, and CgGATA 3. These results collectively suggested that the primary stimulation of V. splendidus led to immune priming in

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

    SciTech Connect

    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 CdCl{sub 2} 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. -- Highlights: •HMG protein ChDSP1 shows affinity to ChHSP70 promoter in Crassostrea hongkongensis. •ChDSP1 negatively regulates ChHSP70 transcription. •ChHSP70 and ChDSP1 transcriptions were coordinately induced by thermal/Cd stress. •ChDSP1 may contribute to the recovery of the induced ChHSP70 to its original state. •This is the first report regarding negative regulator of HSP70 transcription.

  2. Nocardiosis in Mediterranean bivalves: first detection of Nocardia crassostreae in a new host Mytilus galloprovincialis and in Ostrea edulis from the Gulf of Naples (Italy).

    PubMed

    Carella, Francesca; Carrasco, Noelia; Andree, Karl B; Lacuesta, Beatriz; Furones, Dolors; De Vico, Gionata

    2013-11-01

    In this work M. galloprovincialis and O. edulis specimens were surveyed for a pathological study in the Gulf of Naples (Mediterranean sea, Campania Region, southern Italy). Clusters of Nocardia sp.-like cells were observed in histological slides. PCR amplification, sequencing and in situ hybridization were carried out in order to corroborate Nocardia species identification for both hosts. Blast results showed a 99% of maximum identity with Nocardia crassostreae sequences in Genbank. This is the first report of N. crassostreae in the new host M. galloprovincialis and, in a new area, the Mediterranean Sea.

  3. Multiple markers pyrosequencing reveals highly diverse and host-specific fungal communities on the mangrove trees Avicennia marina and Rhizophora stylosa.

    PubMed

    Arfi, Yonathan; Buée, Marc; Marchand, Cyril; Levasseur, Anthony; Record, Eric

    2012-02-01

    Fungi are important actors in ecological processes and trophic webs in mangroves. Although saprophytic fungi occurring in the intertidal part of mangrove have been well studied, little is known about the diversity and structure of the fungal communities in this ecosystem or about the importance of functional groups like pathogens and mutualists. Using tag-encoded 454 pyrosequencing of the ITS1, ITS2, nu-ssu-V5 and nu-ssu-V7 regions, we studied and compared the fungal communities found on the marine and aerial parts of Avicennia marina and Rhizophora stylosa trees in a mangrove in New Caledonia. A total of 209,544 reads were analysed, corresponding to several thousand molecular operational taxonomic units (OTU). There is a marked zonation in the species distribution, with most of the OTU being found specifically in one of the microhabitat studied. Ascomycetes are the dominant phylum (82%), Basidiomycetes are very rare (3%), and 15% of the sequences correspond to unknown taxa. Our results indicate that host specificity is a key factor in the distribution of the highly diverse fungal communities, in both the aerial and intertidal parts of the trees. This study also validates the usefulness of multiple markers in tag-encoded pyrosequencing to consolidate and refine the assessment of the taxonomic diversity.

  4. Matching pollution with adaptive changes in mangrove plants by multivariate statistics. A case study, Rhizophora mangle from four neotropical mangroves in Brazil.

    PubMed

    Souza, Iara da Costa; Morozesk, Mariana; Duarte, Ian Drumond; Bonomo, Marina Marques; Rocha, Lívia Dorsch; Furlan, Larissa Maria; Arrivabene, Hiulana Pereira; Monferrán, Magdalena Victoria; Matsumoto, Silvia Tamie; Milanez, Camilla Rozindo Dias; Wunderlin, Daniel Alberto; Fernandes, Marisa Narciso

    2014-08-01

    Roots of mangrove trees have an important role in depurating water and sediments by retaining metals that may accumulate in different plant tissues, affecting physiological processes and anatomy. The present study aimed to evaluate adaptive changes in root of Rhizophora mangle in response to different levels of chemical elements (metals/metalloids) in interstitial water and sediments from four neotropical mangroves in Brazil. What sets this study apart from other studies is that we not only investigate adaptive modifications in R. mangle but also changes in environments where this plant grows, evaluating correspondence between physical, chemical and biological issues by a combined set of multivariate statistical methods (pattern recognition). Thus, we looked to match changes in the environment with adaptations in plants. Multivariate statistics highlighted that the lignified periderm and the air gaps are directly related to the environmental contamination. Current results provide new evidences of root anatomical strategies to deal with contaminated environments. Multivariate statistics greatly contributes to extrapolate results from complex data matrixes obtained when analyzing environmental issues, pointing out parameters involved in environmental changes and also evidencing the adaptive response of the exposed biota. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Linking physiological processes with mangrove forest structure: phosphorus deficiency limits canopy development, hydraulic conductivity and photosynthetic carbon gain in dwarf Rhizophora mangle.

    PubMed

    Lovelock, Catherine E; Ball, Marilyn C; Choat, Brendan; Engelbrecht, Bettina M J; Holbrook, N Michelle; Feller, Ilka C

    2006-05-01

    Spatial gradients in mangrove tree height in barrier islands of Belize are associated with nutrient deficiency and sustained flooding in the absence of a salinity gradient. While nutrient deficiency is likely to affect many parameters, here we show that addition of phosphorus (P) to dwarf mangroves stimulated increases in diameters of xylem vessels, area of conductive xylem tissue and leaf area index (LAI) of the canopy. These changes in structure were consistent with related changes in function, as addition of P also increased hydraulic conductivity (Ks), stomatal conductance and photosynthetic assimilation rates to the same levels measured in taller trees fringing the seaward margin of the mangrove. Increased xylem vessel size and corresponding enhancements in stem hydraulic conductivity in P fertilized dwarf trees came at the cost of enhanced mid-day loss of hydraulic conductivity and was associated with decreased assimilation rates in the afternoon. Analysis of trait plasticity identifies hydraulic properties of trees as more plastic than those of leaf structural and physiological characteristics, implying that hydraulic properties are key in controlling growth in mangroves. Alleviation of P deficiency, which released trees from hydraulic limitations, reduced the structural and functional distinctions between dwarf and taller fringing tree forms of Rhizophora mangle.

  6. The distribution and abundance of Sphaeroma terebrans, a wood-boring isopod of red mangrove (Rhizophora mangle) habitat within Tampa Bay

    USGS Publications Warehouse

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

    2005-01-01

    This study was conducted to determine the distribution, abundance, and demography of a wood boring isopod, Sphaeroma terebrans Bate, 1866, within the prop roots of the red mangrove, Rhizophora mangle L., in eight sites within Tampa Bay, Florida. Sphaeroma terebrans in Tampa Bay displayed reproductive activity year-round and bay-wide synchrony in their density pattern. On average approximately 60% (range: 25%-86%) of the intertidal aerial roots surveyed were occupied by S. terebrans. Although infestation levels by S. terebrans in Tampa Bay were similar to that of more tropical regions, the distribution of S. terebrans was not continuous throughout the study sites. A substantially higher occurrence and density of S. terebrans was found in the northern compared to more southern study sites within the Bay. Additionally, some seemingly suitable areas of the bay (i.e., Pinellas Point, Skyway, Fort Desoto) were actually unoccupied on some dates. Although sites differed in the frequency with which roots were attacked, the density of burrows and isopods in an occupied root was similar, with most attacked roots containing 3-5 burrows. The results of a transplantation experiment indicated that neither abiotic factors nor substrate quality limit the burrowing capabilities or survival of adult S. terebrans in the areas where they are absent. Instead, dispersal limitation, linked with differential juvenile survival, most likely controls isopod distribution and abundance within Tampa Bay.

  7. 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.

  8. 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

    2016-05-19

    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.

  9. The Effects of Salinity on the Filtration Rates of Juvenile Tropical Oyster Crassostrea iredalei.

    PubMed

    Chang, Geraldine Olive Ju Lien; Inn, Lai Ven; Hwai, Aileen Tan Shau; Yasin, Zulfigar

    2016-11-01

    A small scale laboratory study was conducted to determine the effects of salinity ranging from 15, 20, 25, 30, 35, 40, and 45 ppt on the filtration rates of juvenile oyster Crassostrea iredalei with 25 ppt as the control. Three juvenile oysters (shell weight: 1.04 ± 0.12 g; shell length: 1.9 ± 0.2 cm; shell height: 1.9 ± 0.1 cm) were used to test the filtration rates in each salinity over the course of 8 hours. The hourly filtration rates were determined from the exponential decrease in algal (Chaetoceros calcitrans) concentration as a function of time. The oyster in 35 ppt salinity produced the highest overall filtration rate (FR2) with 134.06 ± 15.66 mL(-1) hr(-1) oyster(-1) and the lowest overall filtration rate (FR2) occurred in oyster exposed to 15 ppt and 45 ppt with 31.30 ± 6.90 mL(-1) hr(-1) oyster(-1) and 32.11 ± 7.68 mL(-1) hr(-1) oyster(-1) respectively throughout the 8 hours. The result from this study can be useful for optimum oyster culturing and the oysters can be employed as a natural biofilter in marine polyculture farming.

  10. Response to selection for fast growth in the second generation of Pacific oyster ( Crassostrea gigas)

    NASA Astrophysics Data System (ADS)

    Wang, Qingzhi; Li, Qi; Kong, Lingfeng; Yu, Ruihai

    2012-09-01

    Mass selection for fast growth was conducted in three Pacific oyster ( Crassostrea gigas) stocks from China, Japan and Korea using previously established lines (CS1, JS1, and KS1). To determine whether continuous progress can be achieved by selection for growth, the progeny of three second-generation Pacific oyster lines was selected for shell height and evaluated via a 400-day farming experiment. When harvested at the end of the experiment, the selected crosses of CS2, JS2, and KS2 lines grew by 9.2%, 10.2% and 9.6% larger than the control crosses, respectively. During grow-out stage, the genetic gain of three selected lines was (10.2 ± 1.4)%, (10.4 ± 0.3)%, and (8.4 ± 1.6)%, respectively; and the corresponding realized heritability was 0.457 ± 0.143, 0.312 ± 0.071 and 0.332 ± 0.009, respectively. These results indicated that the selection for fast growth achieved steady progress in the second generation of oyster. Our work provides supportive evidence for the continuity of the Pacific oyster selective breeding program.

  11. Pathogenicity testing of shellfish hatchery bacterial isolates on Pacific oyster Crassostrea gigas larvae.

    PubMed

    Estes, Robyn M; Friedman, Carolyn S; Elston, Ralph A; Herwig, Russell P

    2004-03-10

    Bacterial diseases are a major cause of larval mortality in shellfish hatcheries. Even with proper sanitation measures, bacterial pathogens cannot be eliminated in all cases. The pathogenicity of bacteria isolated from Pacific Northwest shellfish hatcheries to Pacific oyster Crassostrea gigas larvae was investigated. We found 3 highly pathogenic strains and 1 mildly pathogenic strain among 33 isolates tested. These strains appear to be members of the genus Vibrio. Although there have been many studies of bivalve bacterial pathogens, a standard method to assess bacterial pathogenicity in bivalve larvae is needed. Thus, we developed 2 methods using either 15 ml conical tubes or tissue culture plates that were employed for rapidly screening bacterial strains for pathogenicity to Pacific oyster larvae. The tissue culture plates worked well for screening both mildly pathogenic strains and LD50 (lethal dose) assays. This method allowed for non-intrusive and non-destructive observation of the oyster larvae with a dissecting microscope. The LD50 for the 3 highly pathogenic strains ranged between 1.6 and 3.6 x 10(4) colony forming units (CFU) ml(-1) after 24 h and between 3.2 x 102 and 1.9 x 10(3) CFU ml(-1) after 48 h.

  12. 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. 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.

  14. Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

    PubMed Central

    Garcia, Miranda M.; Smee, Delbert L.

    2017-01-01

    By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging. PMID:28265512

  15. Occurrence and characteristics of agglutination of Vibrio cholerae by serum from the eastern oyster, Crassostrea virginica.

    PubMed Central

    Tamplin, M L; Fisher, W S

    1989-01-01

    Cell-free hemolymph (serum) of the eastern oyster, Crassostrea virginica, agglutinated Vibrio cholerae, including all O1 serovars and biovars. Seventy-nine other strains of bacteria, including 14 genera and 26 species, were not agglutinated. The A, B, and C factors of O1 antigen were not involved in agglutination. Bacterial agglutinating (BA) activity was demonstrated for oysters inhabiting different environments of the U.S. Atlantic and Gulf coasts. Oyster serum BA titers showed high individual variation. The serum component(s) involved in BA was inhibited by 80 degrees C heat, pronase, EDTA, mucin, and fetuin treatments. N-Acetylneuraminic acid (10 mg/ml) weakly inhibited BA activity. Ligands of V. cholerae were sensitive to neuraminidase and resistant to 80 degrees C and pronase. High salinities (24 and 30%) enhanced BA. Cross-adsorption tests with V. cholerae and human O+ erythrocytes indicated that BA and hemagglutinating activities may involve different serum components. These results imply that the ecology of V. cholerae in C. virginica is influenced by agglutinating activity of oyster serum. PMID:2483041

  16. Conservation and divergence of mitochondrial apoptosis pathway in the Pacific oyster, Crassostrea gigas

    PubMed Central

    Li, Yingxiang; Zhang, Linlin; Qu, Tao; Tang, Xueying; Li, Li; Zhang, Guofan

    2017-01-01

    Apoptosis is considered a crucial part of the host defense system in oysters according to previous reports; however, the exact process by which this occurs remains unclear. Besides, mitochondrial apoptosis is the primary method of apoptosis in vertebrate cells, but has been poorly studied in invertebrates and is quite controversial. In this study, we investigated the molecular mechanism of mitochondrial apoptosis in the Pacific oyster Crassostrea gigas. Notably, we show that most key elements involved in the vertebrate mitochondrial apoptosis pathway – including mitochondrial outer membrane permeabilization, cytochrome c release, and caspase activation – are also present in C. gigas. In contrast, the lack of Bcl-2 homology 3-only subfamily members and apoptotic protease activating factor-1 (APAF-1) protein revealed evolutionary diversity from other phyla. Our results support that mitochondrial apoptosis in animals predates the emergence of vertebrates, but suggest that an unexpectedly diverse mitochondrial apoptosis pathway may exist in invertebrates. In addition, our work provided new clues for an improved understanding of how bivalve acclimate themselves to an inconstant environment. PMID:28682310

  17. Identification and Functional Characterization of the Glycogen Synthesis Related Gene Glycogenin in Pacific Oysters (Crassostrea gigas).

    PubMed

    Li, Busu; Meng, Jie; Li, Li; Liu, Sheng; Wang, Ting; Zhang, Guofan

    2017-09-06

    High glycogen levels in the Pacific oyster (Crassostrea gigas) contribute to its flavor, quality, and hardiness. Glycogenin (CgGN) is the priming glucosyltransferase that initiates glycogen biosynthesis. We characterized the full sequence and function of C. gigas CgGN. Three CgGN isoforms (CgGN-α, β, and γ) containing alternative exon regions were isolated. CgGN expression varied seasonally in the adductor muscle and gonadal area and was the highest in the adductor muscle. Autoglycosylation of CgGN can interact with glycogen synthase (CgGS) to complete glycogen synthesis. Subcellular localization analysis showed that CgGN isoforms and CgGS were located in the cytoplasm. Additionally, a site-directed mutagenesis experiment revealed that the Tyr200Phe and Tyr202Phe mutations could affect CgGN autoglycosylation. This is the first study of glycogenin function in marine bivalves. These findings will improve our understanding of glycogen synthesis and accumulation mechanisms in mollusks. The data are potentially useful for breeding high-glycogen oysters.

  18. 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.

  19. 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.

  20. The neuroendocrine immunomodulatory axis-like pathway mediated by circulating haemocytes in pacific oyster Crassostrea gigas

    PubMed Central

    Liu, Zhaoqun; Zhou, Zhi; Jiang, Qiufen; Yi, Qilin; Qiu, Limei; Song, Linsheng

    2017-01-01

    The neuroendocrine-immune (NEI) regulatory network is a complex system, which plays an indispensable role in the immunity of host. In this study, a neuroendocrine immunomodulatory axis (NIA)-like pathway mediated by the nervous system and haemocytes was characterized in the oyster Crassostrea gigas. Once invaded pathogen was recognized by the host, the nervous system would temporally release neurotransmitters to modulate the immune response. Instead of acting passively, oyster haemocytes were able to mediate neuronal immunomodulation promptly by controlling the expression of specific neurotransmitter receptors on cell surface and modulating their binding sensitivities, thus regulating intracellular concentration of Ca2+. This neural immunomodulation mediated by the nervous system and haemocytes could influence cellular immunity in oyster by affecting mRNA expression level of TNF genes, and humoral immunity by affecting the activities of key immune-related enzymes. In summary, though simple in structure, the ‘nervous-haemocyte’ NIA-like pathway regulates both cellular and humoral immunity in oyster, meaning a world to the effective immune regulation of the NEI network. PMID:28077596

  1. MOLECULAR GENETIC ANALYSIS OF A STEPPED MULTILOCUS CLINE IN THE AMERICAN OYSTER (CRASSOSTREA VIRGINICA).

    PubMed

    Hare, Matthew P; Avise, John C

    1996-12-01

    Gulf of Mexico versus Atlantic populations of several coastal species in the southeastern United States are known to differ sharply in genetic composition, but most transitional zones have not previously been examined in detail. Here we employ molecular markers from mitochondrial and nuclear loci to characterize cytonuclear genetic associations at meso- and microgeographic scales along an eastern Florida transitional zone between genetically distinct Atlantic and Gulf populations of the American oyster, Crassostrea virginica. The single- and multilocus cytonuclear patterns display: (1) a cline extending along 340 km of the east Florida coastline; (2) a pronounced step in the cline centered at Cape Canaveral (shifts in allelic frequencies by 50-75% over a 20 km distance); (3) a close agreement of observed genotypic frequencies with Hardy-Weinberg expectations within locales; and (4) mild or nonexistent nuclear and cytonuclear disequilibria in most local population samples. These results imply: (1) considerable restrictions to interpopulational gene flow along the eastern Florida coastline; (2) within locales, free interbreeding (as opposed to mere population admixture) between Gulf and Atlantic forms of oysters; and (3) localized population recruitment in the transition zone localities. These findings demonstrate that marine organisms with high dispersal potential via long-lived pelagic larvae can nonetheless display pronounced spatial population genetic structure, and more generally they exemplify the utility of pronounced genetic transition zones for the study of population level processes. © 1996 The Society for the Study of Evolution.

  2. 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

  3. The Pacific oyster (Crassostrea gigas) Hsp70 modulates the Ostreid herpes virus 1 infectivity.

    PubMed

    De-la-Re-Vega, Enrique; Sánchez-Paz, Arturo; Gallardo-Ybarra, Carolina; Lastra-Encinas, Manuel Adolfo; Castro-Longoria, Reina; Grijalva-Chon, José Manuel; López-Torres, Marco Antonio; Maldonado-Arce, Amir Dario

    2017-10-03

    The Ostreid herpes virus type 1 (OsHV-1) is one of the most devastating pathogen in oyster cultures. Among several factors, as food limitation, oxygen depletion, salinity and temperature variations, episodes of "summer mortality" of the Pacific oyster Crassostrea gigas have also been associated with OsHV-1 infection. Mortalities of C. gigas spat and juveniles have increased significantly in Europe, and contemporary mortality records of this mollusk in México have been associated with the occurrence of OsHV-1. In the present study, the expression of the heat shock protein 70 gene from the Pacific oyster correlates with the abundance of DNA polymerase transcripts from the OsHV-1. This may suggest that the induction on the expression of the Pacific oyster hsp70 may potentially participate in the immune response against the virus. Furthermore, this study reports for the first time a TEM representative image of the OsHV-1 in aqueous solution, which possesses an icosahedral shape with a diameter of 70 nm × 100 nm. Finally, the examined sequence encoding the DNApol of the OsHV-1 isolate from northwest Mexico showed specific sequence variations when compared with OsHV-1 isolates from distant geographical areas. Copyright © 2017. Published by Elsevier Ltd.

  4. Bioaccumulation and metabolomics responses in oysters Crassostrea hongkongensis impacted by different levels of metal pollution.

    PubMed

    Cao, Chen; Wang, Wen-Xiong

    2016-09-01

    Jiulong River Estuary, located in southern China, was heavily contaminated by metal pollution. In this study, the estuarine oysters Crassostrea hongkongensis were transplanted to two sites with similar hydrological conditions but different levels of metal pollution in Jiulong River Estuary over a six-month period. We characterized the time-series change of metal bioaccumulation and final metabolomics responses of oysters. Following transplantation, all metals (Cd, Cu, Cr, Ni, Pb, and Zn) in the oyster digestive glands had elevated concentrations over time. By the end of six-month exposure, Cu, Zn and Cd were the main metals significantly differentiating the two sites. Using (1)H NMR metabolite approach, we further demonstrated the disturbance in osmotic regulation, energy metabolism, and glycerophospholipid metabolism induced by metal contaminations. Six months later, the oysters transplanted in the two sites showed a similar metabolite variation pattern when compared with the initial oysters regardless of different metal levels in the tissues. Interestingly, by comparing the oysters from two sites, the more severely polluted oysters accumulated significantly higher amounts of osmolytes (betaine and homarine) and lower energy storage compounds (glycogen) than the less polluted oysters; these changes could be the potential biomarkers for different levels of metal pollution. Our study demonstrated the complexity of biological effects under field conditions, and NMR metabolomics provides an important approach to detect sensitive variation of oyster inner status.

  5. Antimicrobial histones and DNA traps in invertebrate immunity: evidences in Crassostrea gigas.

    PubMed

    Poirier, Aurore C; Schmitt, Paulina; Rosa, Rafael D; Vanhove, Audrey S; Kieffer-Jaquinod, Sylvie; Rubio, Tristan P; Charrière, Guillaume M; Destoumieux-Garzón, Delphine

    2014-09-05

    Although antimicrobial histones have been isolated from multiple metazoan species, their role in host defense has long remained unanswered. We found here that the hemocytes of the oyster Crassostrea gigas release antimicrobial H1-like and H5-like histones in response to tissue damage and infection. These antimicrobial histones were shown to be associated with extracellular DNA networks released by hemocytes, the circulating immune cells of invertebrates, in response to immune challenge. The hemocyte-released DNA was found to surround and entangle vibrios. This defense mechanism is reminiscent of the neutrophil extracellular traps (ETs) recently described in vertebrates. Importantly, oyster ETs were evidenced in vivo in hemocyte-infiltrated interstitial tissues surrounding wounds, whereas they were absent from tissues of unchallenged oysters. Consistently, antimicrobial histones were found to accumulate in oyster tissues following injury or infection with vibrios. Finally, oyster ET formation was highly dependent on the production of reactive oxygen species by hemocytes. This shows that ET formation relies on common cellular and molecular mechanisms from vertebrates to invertebrates. Altogether, our data reveal that ET formation is a defense mechanism triggered by infection and tissue damage, which is shared by relatively distant species suggesting either evolutionary conservation or convergent evolution within Bilateria.

  6. Exploring relationships of calcification rate with respiration rate and predator cue presence in juvenile Crassostrea virginica

    NASA Astrophysics Data System (ADS)

    McCutcheon, M.; Hu, X.

    2016-02-01

    The eastern oyster (Crassostrea virginica) is a biologically and economically important calcifier that has been experiencing a global population decline due to multiple stressors. The process of biomineralization is essential in the growth and predator defense of oysters. Several studies investigating morphological and mechanical shell properties have noted a phenotypic plasticity in response to predator presence. We present the first study that attempts to detect an alteration in the calcification rate of juvenile C. virginica as well as measure respiration rates in the presence and absence of predator exudates. An alkalinity anomaly technique was used to quantify calcification and respiration rates of oysters exposed to blue crab or mud crab cues or a no cue control condition. No significant differences in calcification rate were detected between predator and control treatments. However, the linear relationship between calcification and respiration rates differed between treatments. This changing relationship is not fully understood and warrants further investigation. In addition, this study also revealed our experimental oysters maintained calcification rates comparable to literature values while respiration rates were an order of magnitude lower than previously reported levels. Future direction for this research involves inclusion of acidification treatments. Any environmental factors (including predator presence) that may on their own or in conjunction with estuarine acidification alter calcification (or respiration) rates will impact the local to regional carbon cycle as well as oyster fitness and consequent future population dynamics.

  7. 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.

  8. [Effect of probiotic bacteria on survival and growth of Cortez oyster larvae, Crassostrea corteziensis (Bivalvia: Ostreidae)].

    PubMed

    Campa-Córdova, Angel Isidro; Luna-González, Antonio; Mazón-Suastegui, José Manuel; Aguirre-Guzmán, Gabriel; Ascencio, Felipe; González-Ocampo, Héctor Abelardo

    2011-03-01

    Disease control problems have major constraints in aquaculture production, and the use of probiotics in larviculture is a valid alternative to antibiotics. This study analyzed the effect of probiotic bacteria on survival and final size of Cortez oyster larvae Crassostrea corteziensis. Two different probiotic concentrations were evaluated, 1 x 10(4) and 1 x 10(5) CFU/ml of Lactic acid bacteria (strain NS61) isolated from Nodipecten subnodosus, and bacilli isolated from the white leg shrimp, Litopenaeus vannamei (Pseudomonas aeruginosa, strain YC58) and C. corteziensis (Burkholderia cepacia, strain Y021). Bacteria were added directly into culture tanks, starting the bioassays from veliger to pediveliger stages as follows: (1) Control, without probiotics; (2) lactic acid bacteria (Lb); (3) bacilli mix (Mb) in a proportion 1:1. Results showed a higher larval survival with Lb and Mb at a dose of 1 x 10(4) CFU/ml compared to the control group. Larvae exposed to Mb at 1 x 10(5) CFU/ml showed higher survival than Lb and control. Larval final size was not significantly increased with the tested probiotics, but larvae treated with Lb at 1 x 10(5) CFU/ml showed less survival rate than those treated at 1 x 10(4) CFU/ml. This study showed the beneficial effect of these probiotics, added individually or mixed in C. corteziensis larvae culture.

  9. Mercury in the bivalves Anadara (Senilia) senilis, Perna perna and Crassostrea tulipa from Ghana.

    PubMed

    Otchere, Fred A; Joiris, Claude R; Holsbeek, Ludo

    2003-03-20

    Three bivalves: Anadara (Senilia) senilis (n=220), Crassostrea tulipa (n=260) from two 'open' lagoons (Benya and Ningo) and a 'closed' lagoon (Sakumo), and Perna perna (n=170) from rocky shores adjacent to Benya and Sakumo, were analyzed for their total and organic Hg concentrations and total body burden. Median concentrations for cockles were 0.20 micro/gdw for the wet season and 0.36 microg/gdw for the dry season. Total mercury concentration for both mussels and oysters ranged from 0.04 to 0.84 microg/gdw. Seasonal variations and age effect were detected in all the species but no significant spatial variation was found along the coast. Organic (methyl) mercury concentration ranged from 0.03 to 0.55 microg/gdw was stable without age effect. The median relative organic mercury varied between 30 and 80% depending on the season, location, species and the type of lagoon. The lower concentrations in the wet season were due to primary production and dilution effect. Log-transformed regression relationships between body burden and size were used to compare the species.

  10. 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

  11. Viral gametocytic hypertrophy of Crassostrea gigas in France: from occasional records to disease emergence?

    PubMed

    Garcia, Céline; Robert, Maeva; Arzul, Isabelle; Chollet, Bruno; Joly, Jean-Pierre; Miossec, Laurence; Comtet, Thierry; Berthe, Franck

    2006-06-23

    Viral gametocytic hypertrophy was reported for the first time in 2001 in Pacific oyster Crassostrea gigas in France. Since this date, the number of reported cases and the distribution area have increased every year; however, the cases are not associated with macroscopic signs or increased mortality rates. Both male and female gametes were hypertrophied and basophilic inclusions were observed in gamete nuclei. Transmission electron microscopy revealed the presence of viral particles in these intranuclear basophilic inclusions. These particles had characteristics similar to those of the Papillomaviridae and Polyoma viridae families: they were small, non-enveloped, icosahedral, and 44 to 56 nm in diameter. The viral particles were found in male, female and hermaphrodite oysters and no significant difference in viral infection was observed between those groups. The frequency of detection and the intensity of infection were low and no host defence reaction was recognised, suggesting that the viral particles had a weak impact on C. gigas. The viral particles described in the present study seem to be similar to these described in C. virginica in the USA and Canada and in C. gigas in Korea, but further studies are required to confirm their identity. The issue of a possible emergence of this infection is discussed.

  12. 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.

  13. Endonuclease banding reveals that atrazine-induced aneuploidy resembles spontaneous chromosome loss in Crassostrea gigas.

    PubMed

    Bouilly, Karine; Leitão, Alexandra; Chaves, Raquel; Guedes-Pinto, Henrique; Boudry, Pierre; Lapègue, Sylvie

    2005-02-01

    Aneuploidy has previously been observed in the Pacific oyster, Crassostrea gigas, and shown to be negatively correlated with growth. Moreover, a significant impact of atrazine exposure has been described in C. gigas, and persistence of that effect has been observed between generations. Evidence of differential chromosome loss has been demonstrated in aneuploid karyotypes of C. gigas using the G-banding technique. Pairs 1, 5, 9, and 10 are characterized by the loss of 1 chromosome. As restriction enzyme (RE) digestion chromosome banding allows a better identification of chromosome pairs, we used this technique to identify which chromosomes are affected when aneuploidy is increased by exposure to atrazine. The progeny of oysters contaminated by atrazine were analysed using the restriction enzyme HaeIII. The study of 26 RE-banded aneuploid karyotypes showed that the same chromosome pairs (1, 5, 9, and 10) were affected by the loss of 1 chromosome (61%, 15%, 42%, and 42%, respectively). Further investigation is required to enable a better understanding of aneuploidy in oysters, especially with respect to why some chromosomes are more easily lost than others, and why cells tolerate the loss of these chromosomes.

  14. 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.

  15. 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.

  16. 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.

  17. Trojan Horse Strategy for Non-invasive Interference of Clock Gene in the Oyster Crassostrea gigas.

    PubMed

    Payton, Laura; Perrigault, Mickael; Bourdineaud, Jean-Paul; Marcel, Anjara; Massabuau, Jean-Charles; Tran, Damien

    2017-08-01

    RNA interference is a powerful method to inhibit specific gene expression. Recently, silencing target genes by feeding has been successfully carried out in nematodes, insects, and small aquatic organisms. A non-invasive feeding-based RNA interference is reported here for the first time in a mollusk bivalve, the pacific oyster Crassostrea gigas. In this Trojan horse strategy, the unicellular alga Heterocapsa triquetra is the food supply used as a vector to feed oysters with Escherichia coli strain HT115 engineered to express the double-stranded RNA targeting gene. To test the efficacy of the method, the Clock gene, a central gene of the circadian clock, was targeted for knockout. Results demonstrated specific and systemic efficiency of the Trojan horse strategy in reducing Clock mRNA abundance. Consequences of Clock disruption were observed in Clock-related genes (Bmal, Tim1, Per, Cry1, Cry2, Rev.-erb, and Ror) and triploid oysters were more sensitive than diploid to the interference. This non-invasive approach shows an involvement of the circadian clock in oyster bioaccumulation of toxins produced by the harmful alga Alexandrium minutum.

  18. Novel antioxidative peptides from the protein hydrolysate of oysters (Crassostrea talienwhanensis).

    PubMed

    Wang, Qiukuan; Li, Wei; He, Yunhai; Ren, Dandan; Kow, Felicia; Song, Linlin; Yu, Xingju

    2014-02-15

    The antioxidative activity of hydrolysate peptides from oysters (Crassostrea talienwhanensis) was investigated. After hydrolysis with subtilisin, the yields of the peptides that were soluble in trichloroacetic acid (TCA-soluble) and the antioxidant activities of the resulting hydrolysate were determined using an orthogonal design and a hydroxyl radical scavenging reaction. The hydrolysate was fractionated using Sephadex G-15 gel filtration chromatography, and the two resulting bioactive peptides were subsequently purified by RP-HPLC with a Kromasil C18 (ODS) column. The amino acid sequences were analyzed by nano-ESI-MS/MS. The critical reaction temperature, pH, hydrolysis time and enzyme-to-substrate (E/S) ratio were determined for the optimum hydrolysis with subtilisin, and the E/S ratio was found to be the most critical reaction condition. The amino acid sequences of the peptides (518 and 440 Da) were proline-valine-methionine-glycine-aspartic acid (PVMGA) and glutamine-histidine-glycine-valine (QHGV), respectively. These two novel peptides exhibited high antioxidative actions based on their hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Effect of Salinity on Embryo and Larval Development of Oyster Crassostrea iredalei

    PubMed Central

    Fang, Amelia Ng Phei; Peng, Teh Chiew; Yen, Poi Khoy; Yasin, Zulfigar; Hwai, Aileen Tan Shau

    2016-01-01

    The effects of salinity on the embryonic and larvae stage of Crassostrea iredalei were investigated. Fertilised eggs and one day old D-larvae were subjected to salinities ranging from 0 to 30 ppt at temperature of 30±2°C. At salinity lower than 10 ppt, 100% mortality was observed. For embryo development, the highest survival was observed at salinity 25 ppt with 80.9±2.2% survival with no significant difference compared to 15 and 30 ppt. Shell height and length were both greatest at salinity 30 ppt. Throughout the 11 days culture, the highest larval survival occurred at salinity 15 ppt with no significant difference compared to all other salinities except 10 ppt. Larval shell sizes showed no significant differences between salinities, except for 10 ppt. Optimum culture condition for larvae growth are salinities ranging from 15 to 30 ppt whereby the larval of this species can tolerate wider range of salinity compared to other oyster species and thus, making it a competitive species to be cultured. PMID:27965737

  20. Gill erosion and herpesvirus in Crassostrea gigas cultured in Baja California, Mexico.

    PubMed

    Vásquez-Yeomans, Rebeca; García-Ortega, Mauricio; Cáceres-Martínez, Jorge

    2010-03-09

    Recurrent episodes of mortality of Crassostrea gigas cultured in northwestern Mexico have been occurring since 1997. Previous studies on bacteria, protozoans, and metazoans as presumptive causal agents have been inconclusive. However, erosions in the marginal indentation of gills have been frequently observed in oysters from areas affected by mortality events, and in 2000 those lesions were associated with the detection of a herpes-like virus. The present study aimed to describe the histological alterations of eroded gills and to determine whether ostreid herpesvirus 1 (OsHV-1) or a related virus was associated with them using in situ hybridization (ISH). Histology showed that gill filaments were fused. In severe cases, deformation of the interlamellar junctions, swelling, and the loss of water channels was observed. ISH analysis revealed the presence of OsHV-1 DNA or a related virus in cells of the gills. Some labeled cells were large with dark granules inside their cytoplasm. These cells were surrounded by infiltrating hemocytes. Some cells interpreted as hemocytes were labeled and observed in eroded and non-eroded areas of the gill. Large cells detected by ISH were also observed by conventional histology with hematoxylin-eosin staining. Whether the virus produces the erosions in the gills, or the erosions in the gills are produced by an unknown condition and favor the presence of the virus, remains unresolved. It is also not clear whether the lesions contribute to mortality.

  1. Toxic effects of heavy metal Cu2+ on the pacific oyster Crassostrea gigas

    NASA Astrophysics Data System (ADS)

    Gao, Ceng; Zhang, Xinxin; Li, Xiumei; Tang, Xuexi

    2017-05-01

    The effects of different concentrations of heavy metal ions on the survival of the Pacific oyster Crassostrea gigas were studied by using experimental ecology method in 96 h. The results showed that the LC50 of copper ion was 21.748mg/L and the safe concentration was 2.1748mg/L mg/L. Under the condition of laboratory, under laboratory conditions, the research of Cu2+ Stress on the C. gigas gill and digestive gland and adductor muscle tissue SOD, GPx and the induction of CAT activity. The results showed that the activities of SOD, GPx and CAT in the C. gigas were significantly changed by copper ion + stress. The results showed that in the low concentration Cu2+ treatment could induce the three kinds of enzymes, in the high concentration Cu2+ treatment group, SOD and CAT and GPx on the inhibition of the effect. The sensitivity of the three antioxidant enzymes to copper ion showed a certain difference. The sensitivity of the three kinds of tissue enzymes to Cu2+ treatment was digestive gland> fascia> gill. The experimental results show that the single factor for copper in water pollutants, the C. gigas digestive gland tissue SOD, GPX and CAT activity has certain significance to it, but will it as index applied to the actual water need further study.

  2. Trace metal contents of the pacific oyster ( Crassostrea gigas) purchased from markets in Hong Kong

    NASA Astrophysics Data System (ADS)

    Cheung, Y. H.; Wong, M. H.

    1992-11-01

    Arsenic, cadmium, chromium, and copper concentrations of the Pacific oyster, Crassostrea gigas, purchased from four different markets were determined in this project. In general, gill tissue had the highest proportion of metal contents (34%-67%) when compared with other tissue parts (mantle, viscera, and adductor muscle), except for arsenic, which showed the highest level in adductor muscle (44%). Smaller oysters (longitudinal length of soft body part less than 6 cm) had higher metal levels than larger ones (longitudinal length of soft body part more than 6 cm), except copper. None of the four metals examined showed an obvious seasonal trend, although cadmium levels seemed to be higher in autumn and winter months. Arsenic, cadmium, and copper levels in oysters purchased from different markets and different months obtained in the present study were higher when compared with past reports. Cadmium levels, as high as 10.98 mg/kg (dry weight basis) have been obtained. This approaches the safety limit that may be hazardous to human health. Continual monitoring of cadmium and other trace metals of toxicological significance to man in Hong Kong seafood is recommended.

  3. 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

  4. Genetically Determined Variation in Developmental Physiology of Bivalve Larvae (Crassostrea gigas).

    PubMed

    Francis Pan, T-C; Applebaum, Scott L; Manahan, Donal T

    2015-01-01

    Understanding the complex interactions that regulate growth and form is a central question in developmental physiology. We used experimental crosses of pedigreed lines of the Pacific oyster, Crassostrea gigas, to investigate genetically determined variations in larval growth and nutrient transport. We show that (i) transport rates at 10 and 100 μM glycine scale differentially with size; (ii) size-specific maximum transport capacity (Jmax) is genetically determined; and (iii) Jmax serves as an early predictive index of subsequent growth rate. This relationship between genetically determined Jmax and growth suggests the potential use of transporter genes as biomarkers of growth potential. Analysis of the genome of C. gigas revealed 23 putative amino acid transporter genes. The complexity of gene families that underpin physiological traits has additional precedents in this species and others and warrants caution in the use of gene expression as a biomarker for physiological state. Direct in vivo measurements of physiological processes using species with defined genotypes are required to understand genetically determined variance of nutrient flux and other processes that regulate development and growth.

  5. 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.

  6. The Effects of Salinity on the Filtration Rates of Juvenile Tropical Oyster Crassostrea iredalei

    PubMed Central

    Chang, Geraldine Olive Ju Lien; Inn, Lai Ven; Hwai, Aileen Tan Shau; Yasin, Zulfigar

    2016-01-01

    A small scale laboratory study was conducted to determine the effects of salinity ranging from 15, 20, 25, 30, 35, 40, and 45 ppt on the filtration rates of juvenile oyster Crassostrea iredalei with 25 ppt as the control. Three juvenile oysters (shell weight: 1.04 ± 0.12 g; shell length: 1.9 ± 0.2 cm; shell height: 1.9 ± 0.1 cm) were used to test the filtration rates in each salinity over the course of 8 hours. The hourly filtration rates were determined from the exponential decrease in algal (Chaetoceros calcitrans) concentration as a function of time. The oyster in 35 ppt salinity produced the highest overall filtration rate (FR2) with 134.06 ± 15.66 mL−1 hr−1 oyster−1 and the lowest overall filtration rate (FR2) occurred in oyster exposed to 15 ppt and 45 ppt with 31.30 ± 6.90 mL−1 hr−1 oyster−1 and 32.11 ± 7.68 mL−1 hr−1 oyster−1 respectively throughout the 8 hours. The result from this study can be useful for optimum oyster culturing and the oysters can be employed as a natural biofilter in marine polyculture farming. PMID:27965740

  7. First characterization of three cyclophilin family proteins in the oyster, Crassostrea ariakensis Gould.

    PubMed

    Xu, Ting; Xie, Jiasong; Yang, Shoubao; Ye, Shigen; Luo, Ming; Wu, Xinzhong

    2016-08-01

    Cyclophilins (CyPs) are a family of proteins that bind the immunosuppressive agent cyclosporin A (CsA) with high-affinity and belong to one of the three superfamilies of peptidyl-prolyl cis-trans isomerases (PPIase). In this report, three cyclophilin genes (Ca-CyPs), including Ca-CyPA, Ca-CyPB and Ca-PPIL3, were identified from oyster, Crassostrea ariakensis Gould in which Ca-CyPA encodes a protein with 165 amino acid sequences, Ca-CyPB encodes a protein with 217 amino acid sequences and Ca-PPIL3 encodes a protein with 162 amino acid sequences. All of the three Ca-CyPs genes contain a typical CyP-PPIase domain with its signature sequences and Ca-CyPB contains an N-signal peptide sequences. Tissue distribution study revealed that Ca-CyPs were ubiquitously expressed in all examined tissues and the highest levels were observed in hemocytes. RLO incubation upregulated the mRNA expression levels of Ca-CyPs, indicating that three Ca-CyPs might be involved in oyster immune response against RLO infection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Population genetics of the black scar oyster, Crassostrea iredalei: repercussion of anthropogenic interference.

    PubMed

    Zainal Abidin, Danial Hariz; Mustaffa, Suzana; Rahim, Masazurah A; Nair, Devakie M; Naim, Darlina Md; Mohd Nor, Siti Azizah

    2016-01-01

    Mitochondrial cytochrome oxidase subunit I (COI) gene was utilized to assess the population genetics of the commercially important black scar oyster, Crassostrea iredalei among 11 populations throughout the west and east coasts Peninsular Malaysia and Sabah (Malaysian Borneo). Overall, populations of C. iredalei demonstrated low nucleotide diversity π (0.000-0.004) and low-to-high haplotype diversity h (0.000-0.795) levels. Genetic structuring was detected between the Peninsular Malaysia and Sabah populations as revealed by the FST analysis. However, the COI gene analyses showed minimal and non-significant (p > 0.05) population differentiation within the east and west coasts Peninsular Malaysia and Sabah regions. This was attributed to both high larval dispersal along the east and west coasts and human-driven spat translocation between the two coastlines due to C. iredalei cultivation practices. Phylogeographic relationships inferences were also conducted to further support these hypotheses. The neutrality and mismatch distribution analyses suggested that C. iredalei had experienced a/several bottleneck event(s), followed by population expansion. The molecular information obtained from this study could be incorporated in a pragmatic aquaculture management strategy of wild broodstock and the hatchery lines of C. iredalei in Malaysia.

  9. 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

    2016-07-21

    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.

  10. 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

    2014-10-08

    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.

  11. Dual analysis of host and pathogen transcriptomes in ostreid herpesvirus 1-positive Crassostrea gigas.

    PubMed

    Rosani, U; Varotto, L; Domeneghetti, S; Arcangeli, G; Pallavicini, A; Venier, P

    2015-11-01

    Ostreid herpesvirus type 1 (OsHV-1) has become a problematic infective agent for the Pacific oyster Crassostrea gigas. In particular, the OsHV-1 μVar subtype has been associated with severe mortality episodes in oyster spat and juvenile oysters in France and other regions of the world. Factors enhancing the infectivity of the virus and its interactions with susceptible and resistant bivalve hosts are still to be understood, and only few studies have explored the expression of oyster or viral genes during productive infections. In this work, we have performed a dual RNA sequencing analysis on an oyster sample with a high viral load. High sequence coverage allowed us to thoroughly explore the OsHV-1 transcriptome and identify the activated molecular pathways in C. gigas. The identification of several highly induced and defence-related oyster transcripts supports the crucial role played by the innate immune system against the virus and opportunistic microbes possibly contributing to subsequent spat mortality.

  12. Mass mortality in bivalves and the intricate case of the Pacific oyster, Crassostrea gigas.

    PubMed

    Barbosa Solomieu, Valérie; Renault, Tristan; Travers, Marie-Agnès

    2015-10-01

    Massive mortality outbreaks in cultured bivalves have been reported worldwide and they have been associated with infection by a range of viral and bacterial pathogens. Due to their economic and social impact, these episodes constitute a particularly sensitive issue in Pacific oyster (Crassostrea gigas) production. Since 2008, mortality outbreaks affecting C. gigas have increased in terms of intensity and geographic distribution. Epidemiologic surveys have lead to the incrimination of pathogens, specifically OsHV-1 and bacteria of the Vibrio genus, in particular Vibrio aestuarianus. Pathogen diversity may partially account for the variability in the outcome of infections. Host factors (age, reproductive status...) including their genetic background that has an impact on host susceptibility toward infection, also play a role herein. Finally, environmental factors have significant effects on the pathogens themselves, on the host and on the host-pathogen interaction. Further knowledge on pathogen diversity, classification, and spread, may contribute toward a better understanding of this issue and potential ways to mitigate the impact of these outbreaks.

  13. Growth and reproductive investment of introduced Pacific oysters Crassostrea gigas in southern European waters

    NASA Astrophysics Data System (ADS)

    Cardoso, Joana F. M. F.; Peralta, Nelson R. E.; Machado, Jorge P.; van der Veer, Henk W.

    2013-02-01

    Growth and reproductive investment of cultured Pacific oysters Crassostrea gigas were studied in two south-western European estuaries: the Ría de Ribadeo in Spain and the Ria Formosa in Portugal. Developing gonads were found in individuals >23.5 mm shell length in the Ria Formosa and >27.5 mm shell length in the Ría de Ribadeo. Although the amount of gonadal mass in relation to total body mass was higher in the Ría de Ribadeo, oysters from this location did not spawn completely. In contrast, oysters from the Ria Formosa completely emptied their gonad during spawning. Reproduction and, consequently, the maximum potential for population expansion may be constrained in both areas: in the Ría de Ribadeo due to suboptimal spawning threshold temperatures and in the Ria Formosa due to higher metabolic costs caused by warmer winter temperatures. Nevertheless, in comparison to northern oyster populations, Portuguese and Spanish populations have higher reproductive output. If suitable environmental conditions are met, expansion of Portuguese and Spanish populations will most likely occur. In the Ria Formosa, where environmental conditions for growth and reproduction are favourable, wild oysters are already observed. In order to follow the dynamics of oyster populations and predict possible negative effects on the ecosystems, it is important to continue monitoring the physiological performance of C. gigas in these areas.

  14. Effects of continuous chlorination on spat of the American oyster (Crassostrea virginica)

    SciTech Connect

    Sheridan, P.F.

    1981-12-01

    Newly settled spat of the American oyster (Crassostrea virginica) exhibited reduced survival and growth when exposed to chronic chlorination (as Na-OCI). Spat exposed to nominal concentrations of 0.250 and 0.500 mg per 1 chlorine-produced oxidant (CPO) had only 20% survival after 12 weeks, compared to 64% survival in controls. Spat growth was retarded by nominal concentrations as low as 0.125 mg per 1 CPO. Shell height of control oysters increased 10% after 12 weeks, while spat exposed to 0.125 mg per 1 CPO grew 39% and spate exposed to 0.250 mg per 1 CPO had no net growth. Surviving spat exposed to 0.500 mg per 1 CPO showed an apparent growth increase in 160%, due mainly to heavy mortality among smaller-sized spat. The numbers of spat (whether surviving or not) that showed any growth over the 12-week exposure period decreased with increasing chlorine concentration. Larger spat were found to be more resistant than smaller spat to increased chlorination. The mechanism of growth inhibition in spat (mantle retraction and cessation of feeding) appeared to be similar to that found in adult oysters exposed to chlorine.

  15. Relationship between Marteilioides chungmuensis infection and reproduction in the Pacific oyster, Crassostrea gigas.

    PubMed

    Tun, Kay Lwin; Itoh, Naoki; Ueki, Noriyuki; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2007-11-01

    Marteilioides chungmuensis, a protozoan paramyxean parasite, infects the oocytes of the Pacific oyster, Crassostrea gigas. The effects of infection on the reproductive cycle of C. gigas were investigated over two consecutive years at Okayama Prefecture, Japan. In male oysters, gonadal development began during February/March, maturity was achieved in June and spawning activity extended from July to September. In November and December, male oysters were not seen, probably because their gonads regressed to connective tissue and they transformed into undifferentiated oysters. By contrast, female oysters, in which parasite spore formation occurred, were still carrying oocytes until the following March and the spawning process of female oysters took 5 months longer than that of males in epizootic areas. The prevalence of M. chungmuensis infection increased from July to September, when most female oysters had their spawning period, and declined from October to the following April when oysters were at the spent stage. The prevalence of infection increased again in May of the following year and high prevalence was observed in the following July. When prevalence was compared between oysters of different age classes, higher prevalence was detected in older than in younger oysters. Histological examination showed that infected oysters produced oocytes continuously and spawned repeatedly from October to March, during which period healthy oysters were reproductively inactive. Parasites can infect the oocytes of infected oysters throughout the longer spawning period. These observations suggest that M. chungmuensis extends the reproductive period of infected oysters for its own reproductive benefit.

  16. Effect of chronic exposure to zinc in young spats of the Pacific oyster (Crassostrea gigas).

    PubMed

    Devos, Alexandre; Voiseux, Claire; Caplat, Christelle; Fievet, Bruno

    2012-12-01

    The marine coastal environment is exposed to a mixture of environmental pollutants of anthropogenic origin, resulting in chronic low concentrations of contaminants. As a consequence, most coastal marine species are exposed to low doses of such pollutants during their entire life. Many marine species live for years in their natural environment, whereas they do not under laboratory exposure conditions. Using early stages of development in laboratory work allows animals to be chronically exposed from an early age over a reasonable experiment period. In the present study, the authors investigated the effect of chronic exposure to zinc in spats of the Pacific oyster (Crassostrea gigas), from metamorphosis up to 10 weeks. The authors investigated integrated biological endpoints that would account for the apparent general health of the animals as well as molecular markers showing more subtle effects that could potentially go unnoticed at a biologically integrated level. The authors measured in parallel both growth and the transcriptional level of target stress genes. Growth was monitored by image analysis of large samples to avoid high variability and ensure statistical robustness. A dose-response relationship was derived from growth data, yielding a median effective concentration (EC50) of 7.55 µM. Stress genes selected on the basis of available RNA sequences in C. gigas included genes involved in chaperone proteins, oxidative stress, detoxification, and cell cycle regulation. Out of nine stress target genes, only metallothionein displayed overexpression in response to high levels of zinc.

  17. Response of the Pacific oyster Crassostrea gigas, Thunberg 1793, to pesticide exposure under experimental conditions.

    PubMed

    Collin, Hélène; Meistertzheim, Anne-Leila; David, Elise; Moraga, Dario; Boutet, Isabelle

    2010-12-01

    Pesticide run-off into the ocean represents a potential threat to marine organisms, especially bivalves living in coastal environments. However, little is known about the effects of environmentally relevant concentrations of pesticides at the individual level. In this study, the suppression subtractive hybridisation technique was used to discover the main physiological function affected by a cocktail of three pesticides (lindane, metolachlor and carbofuran) in the Pacific oyster Crassostrea gigas. Two oyster populations exposed to different pollution levels in the wild were investigated. The pesticide concentrations used to induce stress were close to those found in the wild. In a time course experiment, the expression of three genes implicated in iron metabolism and oxidative stress as well as that of two ubiquitous stress proteins was examined. No clear regulation of gene or protein expression was found, potentially due to a low-dose effect. However, we detected a strong site- and organ-specific response to the pesticides. This study thus (1) provides insight into bivalve responses to pesticide pollution at the level of the transcriptome, which is the first level of response for organisms facing pollution, and (2) raises interesting questions concerning the importance of the sites and organs studied in the toxicogenomic field.

  18. The modulation role of serotonin in Pacific oyster Crassostrea gigas in response to air exposure.

    PubMed

    Dong, Wenjing; Liu, Zhaoqun; Qiu, Limei; Wang, Weilin; Song, Xiaorui; Wang, Xiudan; Li, Yiqun; Xin, Lusheng; Wang, Lingling; Song, Linsheng

    2017-03-01

    Serotonin, also known as 5-hydroxytryptamine (5-HT), is a critical neurotransmitter in the neuroendocrine-immune regulatory network and involved in regulation of the stress response in vertebrates and invertebrates. In the present study, serotonin was found to be widely distributed in the tissues of Pacific oyster Crassostrea gigas, including haemolymph, gonad, visceral ganglion, mantle, gill, labial palps and hepatopancreas, and its concentration increased significantly in haemolymph and mantle after the oysters were exposed to air for 1 d. The apoptosis rate of haemocytes was significantly declined after the oysters received an injection of extra serotonin, while the activity of superoxide dismutase (SOD) in haemolymph increased significantly. After the stimulation of serotonin during air exposure, the apoptosis rate of oyster haemocytes and the concentration of H2O2 in haemolymph were significantly decreased, while the SOD activity was significantly elevated. Furthermore, the survival rate of oysters from 4(th) to 6(th) d after injection of serotonin was higher than that of FSSW group and air exposure group. The results clearly indicated that serotonin could modulate apoptotic effect and redox during air exposure to protect oysters from stress.

  19. Uptake and retention of Vibrio cholerae O1 in the Eastern oyster, Crassostrea virginica.

    PubMed Central

    Murphree, R L; Tamplin, M L

    1995-01-01

    Vibrio cholerae 01, the causative agent of cholera, is known to persist in estuarine environments as endogenous microflora. The recent introduction of V. cholerae 01 into estuaries of the North and South American continents has stimulated the need to determine the effect of controlled purification on reducing this pathogen in edible molluscan shellfish. Experiments defined parameters for the uptake and retention of V. cholerae 01 in tissues of Crassostrea virginica, and these parameters were compared with those for Escherichia coli and Salmonella tallahassee, bacteria which are usually eliminated from moderately contaminated shellfish within 48 h. Oysters accumulated greater concentrations of V. cholerae 01 than E. coli and S. tallahassee. When V. cholerae 01 was exposed to controlled purification at 15, 19 and 25 degrees C over 48 h, it persisted in oysters at markedly higher levels than E. coli and S. tallahassee. The concentration of a V. cholerae 01-specific agglutinin did not positively correlate with the uptake or retention of V. cholerae 01. These data show that state and federally approved controlled purification techniques are not effective at reducing V. cholerae 01 in oysters. PMID:7487003

  20. The effects of glutathione depletion on reproductive success in oysters, Crassostrea virginica.

    PubMed

    Ringwood, A H; Conners, D E

    2000-01-01

    Glutathione (GSH) is a ubiquitous tripeptide that functions as a very important modulator of cellular homeostasis, including detoxification of metals and oxyradicals. Therefore, depletion of GSH may predispose organisms to pollutant stress. Reproductively active oysters (Crassostrea virginica) were exposed to buthionine sulfoximine in the laboratory to deplete gonadal GSH. The effects of metal exposures (Cd and Cu) on fertilization and developmental assays were evaluated using gametes from control and GSH-depleted adults. Fertilization success was not affected by GSH status, i.e. the fertilization rates of gametes derived from GSH-depleted adults were the same or slightly higher. However, GSH depletion did increase the susceptibility of developing embryos to metal toxicity, i.e. adverse effects on embryonic development were observed at lower metal concentrations with gametes derived from GSH-depleted adults. These effects may be related to diminished removal of free radicals or increased availability of metals. Whereas sperm penetration of embryonic membranes and fertilization success may be facilitated by free radicals, the persistence of free radicals during subsequent developmental periods may adversely affect differentiation and normal development. GSH probably also plays an important role in scavenging toxic metals and reducing metal interactions with essential developmental processes. These results suggest that parental depletion of GSH may increase the susceptibility of embryos to metal toxicity.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Effects of subchronic exposure to glyphosate in juvenile oysters (Crassostrea gigas): From molecular to individual levels.

    PubMed

    Mottier, Antoine; Séguin, Alexis; Devos, Alexandre; Pabic, Charles Le; Voiseux, Claire; Lebel, Jean Marc; Serpentini, Antoine; Fievet, Bruno; Costil, Katherine

    2015-06-30

    Glyphosate-based herbicides are extensively used and can be measured in aquatic ecosystems, including coastal waters. The effect of glyphosate on non-target organisms is an issue of worldwide concern. The aim of this study was to investigate the effects of subchronic exposure to glyphosate in juvenile oysters, Crassostrea gigas. Yearling oysters were exposed to three concentrations of glyphosate (0.1, 1 and 100μgL(-1)) for 56days. Various endpoints were studied, from the individual level (e.g., gametogenesis and tissue alterations) to the molecular level (mRNA quantification), including biochemical endpoints such as glutathione-S-transferase (GST) and catalase activities and malondialdehyde content. No mortality and growth occurred during the experiment, and individual biomarkers revealed only slight effects. The levels of gene expression significantly increased in oysters exposed to the highest glyphosate concentration (GST and metallothioneins) or to all concentrations (multi-xenobiotic resistance). These results suggested an activation of defence mechanisms at the molecular level.

  7. 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.

  8. Temperature-dependent stress response in oysters, Crassostrea virginica: pollution reduces temperature tolerance in oysters.

    PubMed

    Lannig, Gisela; Flores, Jason F; Sokolova, Inna M

    2006-09-12

    Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 degrees C and exposed to 50microgl(-1) of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 degrees C but not at 28 degrees C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas.

  9. Effect of Salinity on Embryo and Larval Development of Oyster Crassostrea iredalei.

    PubMed

    Fang, Amelia Ng Phei; Peng, Teh Chiew; Yen, Poi Khoy; Yasin, Zulfigar; Hwai, Aileen Tan Shau

    2016-11-01

    The effects of salinity on the embryonic and larvae stage of Crassostrea iredalei were investigated. Fertilised eggs and one day old D-larvae were subjected to salinities ranging from 0 to 30 ppt at temperature of 30±2°C. At salinity lower than 10 ppt, 100% mortality was observed. For embryo development, the highest survival was observed at salinity 25 ppt with 80.9±2.2% survival with no significant difference compared to 15 and 30 ppt. Shell height and length were both greatest at salinity 30 ppt. Throughout the 11 days culture, the highest larval survival occurred at salinity 15 ppt with no significant difference compared to all other salinities except 10 ppt. Larval shell sizes showed no significant differences between salinities, except for 10 ppt. Optimum culture condition for larvae growth are salinities ranging from 15 to 30 ppt whereby the larval of this species can tolerate wider range of salinity compared to other oyster species and thus, making it a competitive species to be cultured.

  10. 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.

  11. Purification of a novel arthropod defensin from the American oyster, Crassostrea virginica.

    PubMed

    Seo, Jung-Kil; Crawford, J Myron; Stone, Kathryn L; Noga, Edward J

    2005-12-30

    An antimicrobial peptide was purified from acidified gill extract of a bivalve mollusk, the American oyster (Crassostrea virginica), by preparative acid-urea--polyacrylamide gel electrophoresis and reversed-phase high performance liquid chromatography. The 4265.0 Da peptide had 38 amino acids, including 6 cysteines. It showed strongest activity against Gram-positive bacteria (Lactococcus lactis subsp. lactis and Staphylococcus aureus; minimum effective concentrations [MECs] 2.4 and 3.0 microg/ml, respectively) but also had significant activity against Gram-negative bacteria (Escherichia coli D31 and Vibrio parahemolyticus; MECs 7.6 and 15.0 microg/ml, respectively). Comparison of the amino acid sequence with those of other known antimicrobial peptides revealed that the novel peptide had high sequence homology to arthropod defensins, including those from other bivalves, the mussels Mytilus edulis and Mytilus galloprovincialis. This is the first antimicrobial peptide to be isolated from any oyster species and we have named it American oyster defensin (AOD).

  12. Combined effects of arsenic, salinity and temperature on Crassostrea gigas embryotoxicity.

    PubMed

    Moreira, Anthony; Freitas, Rosa; Figueira, Etelvina; Volpi Ghirardini, Annamaria; Soares, Amadeu M V M; Radaelli, Marta; Guida, Marco; Libralato, Giovanni

    2017-08-25

    The combined effects of different salinity and temperature levels on the toxicity of Arsenic (As) were studied on the embryonic development of the oyster Crassostrea gigas. A standardized embryotoxicity test was performed to assess the interactive effects of these stressors, in a full factorial design experiment including a range of salinities (15, 19, 24, 28 and 32), temperatures (16, 20, 24, 28 and 32°C) and As concentrations (100, 300, 600, 1200, 2400µgL(-1)). The embryotoxicity endpoint was about the determination of normal larvae development rates at various conditions, and median effect concentration (EC50) determination for each As exposure condition. Results showed that toxicity induced by As was characterized by retardation of embryonic development observing toxic effects at lower concentrations than previously reported studies. The presence of As in seawater resulted in a narrower range of tolerance to both salinity and temperature. These findings bring new insights on the impacts of a common contaminant on an important shellfish species having a planktonic early life stage development, with potential implications for population survival and ecosystem functioning in a changing environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  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.

  14. 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.

  15. Electrochemical characterization of a bioceramic material: The shell of the Eastern oyster Crassostrea virginica.

    PubMed

    Yoon, Yuhchae; Mount, Andrew S; Hansen, Karolyn M; Hansen, Douglas C

    2011-06-01

    The shell of the Eastern oyster (Crassostrea virginica) is composed of multiple incongruent mineralized layers. This bioceramic composite material was investigated to determine the effects of shell thickness, orientation and layer composition on its electrochemical behavior using electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy-energy dispersive spectroscopy. SEM-EDS analysis of the oyster shell revealed that the multilayered biocomposite material is composed of calcium carbonate (CaCO(3)). EIS measurements in 3.5wt.% NaCl indicated that the impedance of the whole oyster shell in the low frequency region exhibited high impedance values which exhibited a decreasing trend with increasing immersion time. In terms of overall shell thickness, limiting currents measured by potentiodynamic techniques through the shell were observed to increase when the outer layers of the shell were sequentially removed by grinding, thus decreasing the shell thickness. These limiting current values remained relatively constant when the inner layers of the shell were removed. The impedance values of the oyster shell material as measured by EIS were shown to decrease with decreasing shell thickness. These findings suggest that the prismatic (outermost) shell layer in combination with the soluble organic matrix between all shell layers may influence the ionic conductivity through the oyster shell. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. A novel phosphorylated glycoprotein in the shell matrix of the oyster Crassostrea nippona.

    PubMed

    Samata, Tetsuro; Ikeda, Daisuke; Kajikawa, Aya; Sato, Hideyoshi; Nogawa, Chihiro; Yamada, Daishi; Yamazaki, Ryo; Akiyama, Takahiro

    2008-06-01

    We found a novel 52 kDa matrix glycoprotein MPP1 in the shell of Crassostrea nippona that was unusually acidic and heavily phosphorylated. Deduced from the nucleotide sequence of 1.9 kb cDNA, which is likely to encode MPP1 with high probability, the primary structure of this protein shows a modular structure characterized by repeat sequences rich in Asp, Ser and Gly. The most remarkable of these is the DE-rich sequence, in which continuous repeats of Asp are interrupted by a single Cys residue. Disulfide-dependent MPP1 polymers occurring in the form of multimeric insoluble gels are estimated to contain repetitive locations of the anionic molecules of phosphates and acidic amino acids, particularly Asp. Thus, MPP1 and its polymers possess characteristic features of a charged molecule for oyster biomineralization, namely accumulation and trapping of Ca2+. In addition, MPP1 is the first organic matrix component considered to be expressed in both the foliated and prismatic layers of the molluscan shell microstructure. In vitro crystallization assays demonstrate the induction of tabular crystals with a completely different morphology from those formed spontaneously, indicating that MPP1 and its polymers are potentially the agent that controls crystal growth and shell microstructure.

  17. Inheritance and Variation of Genomic DNA Methylation in Diploid and Triploid Pacific Oyster (Crassostrea gigas).

    PubMed

    Jiang, Qun; Li, Qi; Yu, Hong; Kong, Lingfeng

    2016-02-01

    DNA methylation is an important epigenetic mechanism that could be responsive to environmental changes indicating a potential role in natural selection and adaption. In order to evaluate an evolutionary role of DNA methylation, it is essential to first gain a better insight into inheritability. To address this question, this study investigated DNA methylation variation from parents to offspring in the Pacific oyster Crassostrea gigas using fluorescent-labeled methylation-sensitive amplified polymorphism (F-MSAP) analysis. Most of parental methylated loci were stably transmitted to offspring segregating following Medelian expectation. However, methylated loci deviated more often than non-methylated loci and offspring showed a few de novo methylated loci indicating DNA methylation changes from parents to offspring. Interestingly, some male-specific methylated loci were found in this study which might help to explore sex determination in oyster. Despite environmental stimuli, genomic stresses such as polyploidization also can induce methylation changes. This study also compared global DNA methylation level and individual methylated loci between diploid and triploid oysters. Results showed no difference in global methylation state but a few ploidy-specific loci were detected. DNA methylation variation during polyploidization was less than autonomous methylation variation from parents to offspring.

  18. 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.

  19. 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.

  20. 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.

  1. Environmental factors responsible for the incidence of antibiotic resistance genes in pristine Crassostrea virginica reefs.

    PubMed

    Barkovskii, Andrei L; Thomas, Michael; Hurley, Dorset; Teems, Clifford

    2012-12-01

    The occurrence of tetracycline resistance (TRG) and integrase (INT) genes were monitored in Crassostrea virginica oyster reefs of three pristine creeks (SINERR, Georgia, USA). Their profiles revealed 85% similarity with the TRG/INT profiles observed in the adjacent to the SINERR and contaminated Altamaha River estuary (Barkovskii et al., 2010). The TRG/INT spectra and incidence frequencies corresponded to the source of oceanic input and to run-offs from creeks' watersheds. The highest incidence frequencies and concentrations were observed in oysters. TRG/INT incidences correlated positively (Spearman Rank=0.88), and negatively correlated (-0.63 to -0.79) with creek salinity, conductivity, dissolved solids, and temperature. Coliform incidence positively correlated with temperature, and not with the TRG/INT incidence. The Altamaha River estuary was the primary TRG/INT source for the reefs with contributions from creek's watersheds. TRG/INT were carried by non-coliforms with a preference for low-to-temperate thermohaline environments coupled with bioaccumulation by oysters. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. A novel molluscan Fos gene with immune defense function identified in the Hong Kong oyster, Crassostrea hongkongensis.

    PubMed

    Qu, Fufa; Xiang, Zhiming; Wang, Fuxuan; Zhang, Yang; Tong, Ying; Li, Jun; Zhang, Yuehuan; Yu, Ziniu

    2015-07-01

    The transcription factor Fos is a member of one of the best-studied AP-1 sub-families and has been implicated in a wide variety of biological processes, including the regulation of apoptosis, immune responses and cytokine production. In this report, a novel mollusk Fos (referred to as ChFos) gene was cloned and characterized from the Hong Kong oyster, Crassostrea hongkongensis. The deduced ChFos protein sequence comprised 333 amino acids and shared significant homology with invertebrate homologs. Phylogenetic analysis revealed that ChFos clusters with Fos from Crassostrea gigas and Crassostrea ariakensis. Quantitative real-time PCR analysis revealed that ChFos mRNA was broadly expressed in all tested tissues and during different stages of the oyster's embryonic and larval development. In addition, the expression of ChFos mRNA was significantly up-regulated under challenge with microorganisms (Vibrio alginolyticus, Staphylococcus haemolyticus and Saccharomyces cerevisiae) and pathogen-associated molecular patterns (PAMPs: LPS, PGN and polyI:C). Moreover, fluorescence microscopy showed that ChFos protein is localized in the nucleus in HEK293T cells. Reporter assays suggested that ChFos may act as an efficient transcription activator in the regulation of AP-1-responsive gene expression through interaction with ChJun. Overall, this study presents the first experimental evidence of the presence and functional characteristics of Fos in mollusks, which reveals its involvement in host protection against immune challenge in the oyster. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. GigaTON: an extensive publicly searchable database providing a new reference transcriptome in the pacific oyster Crassostrea gigas.

    PubMed

    Riviere, Guillaume; Klopp, Christophe; Ibouniyamine, Nabihoudine; Huvet, Arnaud; Boudry, Pierre; Favrel, Pascal

    2015-12-02

    The Pacific oyster, Crassostrea gigas, is one of the most important aquaculture shellfish resources worldwide. Important efforts have been undertaken towards a better knowledge of its genome and transcriptome, which makes now C. gigas becoming a model organism among lophotrochozoans, the under-described sister clade of ecdysozoans within protostomes. These massive sequencing efforts offer the opportunity to assemble gene expression data and make such resource accessible and exploitable for the scientific community. Therefore, we undertook this assembly into an up-to-date publicly available transcriptome database: the GigaTON (Gigas TranscriptOme pipeliNe) database. We assembled 2204 million sequences obtained from 114 publicly available RNA-seq libraries that were realized using all embryo-larval development stages, adult organs, different environmental stressors including heavy metals, temperature, salinity and exposure to air, which were mostly performed as part of the Crassostrea gigas genome project. This data was analyzed in silico and resulted into 56621 newly assembled contigs that were deposited into a publicly available database, the GigaTON database. This database also provides powerful and user-friendly request tools to browse and retrieve information about annotation, expression level, UTRs, splice and polymorphism, and gene ontology associated to all the contigs into each, and between all libraries. The GigaTON database provides a convenient, potent and versatile interface to browse, retrieve, confront and compare massive transcriptomic information in an extensive range of conditions, tissues and developmental stages in Crassostrea gigas. To our knowledge, the GigaTON database constitutes the most extensive transcriptomic database to date in marine invertebrates, thereby a new reference transcriptome in the oyster, a highly valuable resource to physiologists and evolutionary biologists.

  4. Perkinsus beihaiensis (Perkinsozoa) in oysters of Bahia State, Brazil.

    PubMed

    Luz, M S A; Carvalho, F S; Oliveira, H C; Boehs, G

    2017-08-17

    This study reports the pathogen Perkinsus beihaiensis in oysters of the genus Crassostrea on the coast of the State of Bahia (Brazil), its prevalence, infection intensity and correlation with salinity. Oysters (n = 240) were collected between October and December 2014 at eight sampling stations between latitudes 13°55'S and 15°42'S. The laboratory procedures included macroscopic analysis, histology, culture in Ray's fluid thioglycollate medium (RFTM), Polymerase Chain Reaction (PCR) and DNA sequencing. PCR and sequencing have been used for the genetic identification of oysters as well. Two species of oysters have been identified: Crassostrea rhizophorae and C. brasiliana. In both oyster species P. beihaiensis was the only Perkinsus species detected. In C. rhizophorae, the average prevalence was 82.8% by histology and 65.2% by RFTM. In C. brasiliana, the prevalences were 70.5% and 35.7%, respectively. The higher prevalence of P. beihaiensis in C. rhizophorae was probably influenced by salinity, with which was positively correlated (r> 0.8). In both oysters, P. beihaiensis was located mainly in the gastric epithelium. The infection was generally mild or moderate, without apparent harm to the hosts, but in cases of severe infection, there was hemocytical reaction and tissue disorganization. The generally high prevalence in the region suggests that oysters should be monitored with respect to this pathogen, especially in growing areas.

  5. 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.

  6. The Effects of Copper and Copper Blocking Agents on Gill Mitochondrial O2 Utilization of Crassostrea virginica

    PubMed Central

    Collins, Shanika; McCoy, Kwanza; Catapane, Edward J.; Carroll, Margaret A.

    2010-01-01

    While essential in trace amounts, excess copper is toxic to cells and tissues. Copper is a major aquatic pollutant. Previously, our lab demonstrated that tissues of the bivalve mollusc Crassostrea virginica readily accumulated copper and other metals from their surrounding environment. In this study we showed that O2 consumption in isolated gill mitochondria of C. virginica was impaired by in vitro copper additions and that copper’s deleterious effects on mitochondria respiration could be blocked by the presence of the membrane channel blocker Diltiazam. PMID:21841976

  7. 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.

  8. 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.

  9. Sex Ratio and Sex Reversal in Two-year-old Class of Oyster, Crassostrea gigas (Bivalvia: Ostreidae).

    PubMed

    Park, Jung Jun; Kim, Hyejin; Kang, Seung Wan; An, Cheul Min; Lee, Sung-Ho; Gye, Myung Chan; Lee, Jung Sick

    2012-12-01

    The sex ratio (F:M) in the same population of oyster, Crassostrea gigas at the commencement of the study (2007) was 1:1.0, but changed to 1:2.8 by the end of the study (2008). The sex reversal rate in two-year-old oysters was 40.2%. Specifically, female to male sex reversal rate was 66.1%, which is higher than the male to female sex reversal rate of 21.1%. The sex reversal pattern of C. gigas appears to go from male⇒female⇒male, and as such is determined to be rhythmical hermaphroditism.

  10. Regulation of Hox orthologues in the oyster Crassostrea gigas evidences a functional role for promoter DNA methylation in an invertebrate.

    PubMed

    Saint-Carlier, Emma; Riviere, Guillaume

    2015-06-04

    DNA methylation within promoter regions (PRDM) controls vertebrate early gene transcription and thereby development, but is neglected outside this group. However, epigenetic features in the oyster Crassostrea gigas suggest functional significance of PDRM in invertebrates. To investigate this, reporter constructs containing in vitro methylated oyster Hox gene promoters were transfected into oyster embryos. The influence of in vivo methylation was studied using bisulfite sequencing and DNA methyltransferase inhibition during development. Our results demonstrate that methylation controls the transcriptional activity of the promoters investigated, unraveling a functional role for PRDM in a lophotrochozoan, an important finding regarding the evolution of epigenetic regulation.

  11. Anti-viral gene induction is absent upon secondary challenge with double-stranded RNA in the Pacific oyster, Crassostrea gigas.

    PubMed

    Green, Timothy J; Benkendorff, Kirsten; Robinson, Nick; Raftos, David; Speck, Peter

    2014-08-01

    Oyster farming is one of the most important aquaculture industries in the world. However, its productivity is increasingly limited by viral disease and we do not yet have management practices, such as protective vaccination, that can control these disease outbreaks. Hence, in the current study we investigated the expression of known anti-viral genes in oysters (Crassostrea gigas) in response to primary and secondary encounter with a virus associated molecular pattern (dsRNA), and tested whether a common form of epigenetic gene regulation (DNA methylation) was associated with the expression of these anti-viral genes. Injection of dsRNA into the adductor muscle resulted in the rapid and transient expression of virus recognition receptors (TLR & MDA5), whereas several anti-viral signalling (IRF & SOC-1) and effector (PKR & viperin) genes were still up-regulated at one week post primary challenge (p < 0.05). This primary encounter with dsRNA appeared to deplete the immune system because anti-viral gene induction was absent in the gills when oysters were given a second injection of dsRNA at 1-week post-primary injection. The expression of DNA methylation genes (DNMT1, DNMT3b, TDG, TET2) and DNA methylation profiles up-stream of specific anti-viral genes (STING, SOC-1 & Viperin) did not change in response to dsRNA injection (p > 0.05). These results collectively suggest that C. gigas does not have an enhanced anti-viral gene response (immune-priming) to secondary dsRNA challenge and that the sustained up-regulation of anti-viral signalling and effector genes following primary challenge is unlikely to be associated with upstream DNA methylation levels.

  12. 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

  13. 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

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

    2014-09-01

    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.

  14. 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.

  15. Perkinsus infection is associated with alterations in the level of global DNA methylation of gills and gastrointestinal tract of the oyster Crassostrea gasar.

    PubMed

    Farias, Natanael Dantas; de Oliveira, Naila Francis Paulo; da Silva, Patricia Mirella

    2017-10-01

    Bivalves are filter feeders that obtain food from seawater that may contain infectious agents, such as the protozoan parasites Perkinsus marinus and P. olseni that are associated with massive mortalities responsible for losses in the aquaculture industry. Despite all physical and chemical barriers, microorganisms cross epithelia and infect host tissues to cause pathologies. Epigenetics mechanisms play important roles in a variety of human processes, from embryonic development to cell differentiation and growth. It is currently emerging as crucial mechanism involved in modulation of host-parasite interactions and pathogenesis, promoting discovery of targets for drug treatment. In bivalves, little is known about epigenetic mechanism in host parasite interactions. The objective of the present study was to evaluate the effect of Perkinsus sp. infections on DNA methylation levels in tissues of Crassostrea gasar oysters. Samples were collected in 2015 and 2016 in the Mamanguape River estuary (PB). Oyster gills were removed and used for Perkinsus sp. Gills (G) and gastrointestinal tract (GT), as well as cultured P. marinus trophozoites were preserved in 95% ethanol for DNA extractions. DNA methylation levels were estimated from G and GT tissues of uninfected (n=60) and infected oysters (n=60), and from P. marinus trophozoites, by ELISA assays. Results showed that the mean prevalence of Perkinsus sp. infections was high (87.3%) in 2015 and moderate (59.6%) in 2016. DNA methylation levels of G and GT tissues were significantly lower in infected oyster than in uninfected oysters, suggesting that infections are associated with hypomethylation. Methylation level was significantly higher in G than in GT tissues, indicating a likely tissue-specific mechanism. P. marinus trophozoites showed 33% methylation. This was the first study that confirms alterations of DNA methylation in two tissues of C. gasar oysters in association with Perkinsus sp. infections. Copyright © 2017

  16. 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.

  17. 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.

  18. 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

  19. 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...

  20. Evaluating the performance of selective-bred lines of eastern oysters, Crassostrea virginica, at different locations along the east coast of the United States

    USDA-ARS?s Scientific Manuscript database

    Populations of the economically important eastern oyster, Crassostrea virginica have been severely affected in the last few decades by diseases such as Dermo, MSX, SSO, and ROD. As the demand for a fast-growing, disease-resistant oyster increases, so has the need for effective breeding programs that...

  1. 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...

  2. Effect of acclimatization on hemocyte functional characteristics of the Pacific oyster (Crassostrea gigas) and carpet shell clam (Ruditapes decussatus).

    PubMed

    Hurtado, Miguel Ángel; da Silva, Patricia Mirella; Le Goïc, Nelly; Palacios, Elena; Soudant, Philippe

    2011-12-01

    Most experimental procedures on molluscs are done after acclimatization of wild animals to lab conditions. Similarly, short-term acclimation is often unavoidable in a field survey when biological analysis cannot be done within the day of sample collection. However, acclimatization can affect the general physiological condition and particularly the immune cell responses of molluscs. Our aim was to study the changes in the hemocyte characteristics of the Pacific oyster Crassostrea gigas and the carpet shell clam Ruditapes decussatus acclimated 1 or 2 days under emersed conditions at 14 ± 1 °C and for 1, 2, 7, or 10 days to flowing seawater conditions (submerged) at 9 ± 1 °C, when compared to hemolymph withdrawn from organisms sampled in the field and immediately analyzed in the laboratory (unacclimated). The hemocyte characteristics assessed by flow cytometry were the total (THC) and differential hemocyte count, percentage of dead cells, phagocytosis, and reactive oxygen species (ROS) production. Dead hemocytes were lower in oysters acclimated both in emersed and submerged conditions (1%-5%) compared to those sampled in the field (7%). Compared to oysters, the percentage of dead hemocytes was lower in clams (0.4% vs. 1.1%) and showed a tendency to decrease during acclimatization in both emersed and submerged conditions. In comparison to organisms not acclimated, the phagocytosis of hemocytes decreased in both oysters and clams acclimated under submerged conditions, but was similar in those acclimated in emersed conditions. The ROS production remained stable in both oysters and clams acclimated in emersed conditions, whereas in submerged conditions ROS production did not change in both the hyalinocytes and granulocytes of oysters, but increased in clams. In oysters, the THC decreased when they were acclimated 1 and 2 days in submerged conditions and was mainly caused by a decrease in granulocytes, but the decrease in THC in oysters acclimated 2 days in emersed

  3. 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

  4. Candidate Gene Polymorphisms and their Association with Glycogen Content in the Pacific Oyster Crassostrea gigas

    PubMed Central

    She, Zhicai; Li, Li; Qi, Haigang; Song, Kai; Que, Huayong; Zhang, Guofan

    2015-01-01

    Background The Pacific oyster Crassostrea gigas is an important cultivated shellfish that is rich in nutrients. It contains high levels of glycogen, which is of high nutritional value. To investigate the genetic basis of this high glycogen content and its variation, we conducted a candidate gene association analysis using a wild population, and confirmed our results using an independent population, via targeted gene resequencing and mRNA expression analysis. Results We validated 295 SNPs in the 90 candidate genes surveyed for association with glycogen content, 86 of were ultimately genotyped in all 144 experimental individuals from Jiaonan (JN). In addition, 732 SNPs were genotyped via targeted gene resequencing. Two SNPs (Cg_SNP_TY202 and Cg_SNP_3021) in Cg_GD1 (glycogen debranching enzyme) and one SNP (Cg_SNP_4) in Cg_GP1 (glycogen phosphorylase) were identified as being associated with glycogen content. The glycogen content of individuals with genotypes TT and TC in Cg_SNP_TY202 was higher than that of individuals with genotype CC. The transcript abundance of both glycogen-associated genes was differentially expressed in high glycogen content and low glycogen content individuals. Conclusions This study identified three polymorphisms in two genes associated with oyster glycogen content, via candidate gene association analysis. The transcript abundance differences in Cg_GD1 and Cg_GP1 between low- and the high-glycogen content individuals suggests that it is possible that transcript regulation is mediated by variations of Cg_SNP_TY202, Cg_SNP_3021, and Cg_SNP_4. These findings will not only provide insights into the genetic basis of oyster quality, but also promote research into the molecular breeding of oysters. PMID:25951187

  5. Recovery, Bioaccumulation, and Inactivation of Human Waterborne Pathogens by the Chesapeake Bay Nonnative Oyster, Crassostrea ariakensis

    PubMed Central

    Graczyk, Thaddeus K.; Girouard, Autumn S.; Tamang, Leena; Nappier, Sharon P.; Schwab, Kellogg J.

    2006-01-01

    The introduction of nonnative oysters (i.e., Crassostrea ariakensis) into the Chesapeake Bay has been proposed as necessary for the restoration of the oyster industry; however, nothing is known about the public health risks related to contamination of these oysters with human pathogens. Commercial market-size C. ariakensis triploids were maintained in large marine tanks with water of low (8-ppt), medium (12-ppt), and high (20-ppt) salinities spiked with 1.0 × 105 transmissive stages of the following human pathogens: Cryptosporidium parvum oocysts, Giardia lamblia cysts, and microsporidian spores (i.e., Encephalitozoon intestinalis, Encephalitozoon hellem, and Enterocytozoon bieneusi). Viable oocysts and spores were still detected in oysters on day 33 post-water inoculation (pwi), and cysts were detected on day 14 pwi. The recovery, bioaccumulation, depuration, and inactivation rates of human waterborne pathogens by C. ariakensis triploids were driven by salinity and were optimal in medium- and high-salinity water. The concentration of human pathogens from ambient water by C. ariakensis and the retention of these pathogens without (or with minimal) inactivation and a very low depuration rate provide evidence that these oysters may present a public health threat upon entering the human food chain, if harvested from polluted water. This conclusion is reinforced by the concentration of waterborne pathogens used in the present study, which was representative of levels of infectious agents in surface waters, including the Chesapeake Bay. Aquacultures of nonnative oysters in the Chesapeake Bay will provide excellent ecological services in regard to efficient cleaning of human-infectious agents from the estuarine waters. PMID:16672482

  6. Shotgun proteomics reveals physiological response to ocean acidification in Crassostrea gigas.

    PubMed

    Timmins-Schiffman, Emma; Coffey, William D; Hua, Wilber; Nunn, Brook L; Dickinson, Gary H; Roberts, Steven B

    2014-11-03

    Ocean acidification as a result of increased anthropogenic CO2 emissions is occurring in marine and estuarine environments worldwide. The coastal ocean experiences additional daily and seasonal fluctuations in pH that can be lower than projected end-of-century open ocean pH reductions. In order to assess the impact of ocean acidification on marine invertebrates, Pacific oysters (Crassostrea gigas) were exposed to one of four different p CO2 levels for four weeks: 400 μatm (pH 8.0), 800 μatm (pH 7.7), 1000 μatm (pH 7.6), or 2800 μatm (pH 7.3). At the end of the four week exposure period, oysters in all four p CO2 environments deposited new shell, but growth rate was not different among the treatments. However, micromechanical properties of the new shell were compromised by elevated p CO2. Elevated p CO2 affected neither whole body fatty acid composition, nor glycogen content, nor mortality rate associated with acute heat shock. Shotgun proteomics revealed that several physiological pathways were significantly affected by ocean acidification, including antioxidant response, carbohydrate metabolism, and transcription and translation. Additionally, the proteomic response to a second stress differed with p CO2, with numerous processes significantly affected by mechanical stimulation at high versus low p CO2 (all proteomics data are available in the ProteomeXchange under the identifier PXD000835). Oyster physiology is significantly altered by exposure to elevated p CO2, indicating changes in energy resource use. This is especially apparent in the assessment of the effects of p CO2 on the proteomic response to a second stress. The altered stress response illustrates that ocean acidification may impact how oysters respond to other changes in their environment. These data contribute to an integrative view of the effects of ocean acidification on oysters as well as physiological trade-offs during environmental stress.

  7. 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.

  8. Pollutant effects on Pacific oyster, Crassostrea gigas (Thunberg), hemocytes: screening of 23 molecules using flow cytometry.

    PubMed

    Gagnaire, B; Thomas-Guyon, H; Burgeot, Th; Renault, T

    2006-01-01

    The shellfish industry is an important economic activity in France, occurring mostly in estuarine zones subject to pollution due to anthropogenic activities. The harmful effects of pollutants on species inhabiting these estuarine zones are not well known. Among marine species, bivalve mollusks--particularly Pacific oyster, Crassostrea gigas--may serve a model of interest. The species is sedentary and filter-feeding, which favors bioaccumulation of pollutants in their tissues. Oysters may be suitable for studies on disturbance by pollutants of physiological activities, among which defense mechanisms are poorly documented in bivalves. In this study, effects of pollutants on hemocyte functions were monitored in Pacific oyster, C. gigas. Hemocytes were exposed in vitro to selected pollutants. The strategy for investigating the effects of pollutants on hemocyte functions is based on several biomarkers, which is more relevant than that of published papers based on single-endpoint experiments. Pollutants belonging to the most important groups of xenobiotics (PAHs, PCBs, and pesticides) were selected and their effect on hemocyte activities was analyzed using flow cytometry. Twenty-three pollutants were tested and eight of them showed significant modulation of hemocyte activities. PAHs and PCB 77 induced a decrease of hemocyte activity after an incubation periods of 4 and 24 h at 200 micro mol/L. Three pesticides (2,4D, paraoxon, and chlorothalonil) modulated hemocyte activities. A mixture of eight pesticides also decreased phagocytotic activity. This study is one of the first to investigate the effects of so many pollutants on hemocyte functions at the same time and therefore allows a real comparison of different pollutant effects.

  9. 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

  10. An integrin from oyster Crassostrea gigas mediates the phagocytosis toward Vibrio splendidus through LPS binding activity.

    PubMed

    Jia, Zhihao; Zhang, Tao; Jiang, Shuai; Wang, Mengqiang; Cheng, Qi; Sun, Mingzhe; Wang, Lingling; Song, Linsheng

    2015-11-01

    Integrins are a family of cell adhesion molecules which play important roles in the regulation of cell adhesion, migration, proliferation, apoptosis and phagocytosis. In the present study, the immune function of an integrin from the oyster Crassostrea gigas (designated CgIntegrin) was characterized to understand the regulatory mechanism of hemocyte phagocytosis toward different microbes. The full-length cDNA of CgIntegrin was 2571 bp with an open reading frame (ORF) of 2397 bp, encoding a polypeptide of 799 amino acids. The mRNA transcripts of CgIntegrin were predominantly detected in hemocytes, gonad and adductor muscle, while lowly in hepatopancreas, mantle and gill. The mRNA expression level was up-regulated at 6 h post lipopolysaccharide (LPS) stimulation (p < 0.01), while no significant change was observed after peptidoglycan (PGN) stimulation. The oyster hemocytes with relative high CgIntegrin expression level exhibited different phagocytic abilities towards different microorganism and particles, such as Gram-positive bacteria Vibrio splendidus, Gram-negative bacteria Staphylococcus aureus and latex beads. Moreover, the phagocytic rate towards V. splendidus was significantly decreased after the blockade of CgIntegrin using the polyclonal antibody. The recombinant CgIntegrin (rCgIntegrin) displayed agglutinating activity towards V. splendidus but not S. aureus and Y. lipolytica. It also exhibited a higher binding affinity towards LPS (compared to rTrx group) in a dose-dependent manner with the apparent dissociation constant (Kd) of 5.53 × 10(-6) M. The results indicated that CgIntegrin served as a pattern recognition receptor with LPS binding activity, which could directly bind to V. splendidus and enhance the phagocytosis of oyster hemocytes.

  11. Quantitative Trait Locus Analysis of Stage-Specific Inbreeding Depression in the Pacific Oyster Crassostrea gigas

    PubMed Central

    Plough, Louis V.; Hedgecock, Dennis

    2011-01-01

    Inbreeding depression and genetic load have been widely observed, but their genetic basis and effects on fitness during the life cycle remain poorly understood, especially for marine animals with high fecundity and high, early mortality (type-III survivorship). A high load of recessive mutations was previously inferred for the Pacific oyster Crassostrea gigas, from massive distortions of zygotic, marker segregation ratios in F2 families. However, the number, genomic location, and stage-specific onset of mutations affecting viability have not been thoroughly investigated. Here, we again report massive distortions of microsatellite-marker segregation ratios in two F2 hybrid families, but we now locate the causative deleterious mutations, using a quantitative trait locus (QTL) interval-mapping model, and we characterize their mode of gene action. We find 14–15 viability QTL (vQTL) in the two families. Genotypic frequencies at vQTL generally suggest selection against recessive or partially recessive alleles, supporting the dominance theory of inbreeding depression. No epistasis was detected among vQTL, so unlinked vQTL presumably have independent effects on survival. For the first time, we track segregation ratios of vQTL-linked markers through the life cycle, to determine their stage-specific expression. Almost all vQTL are absent in the earliest life stages examined, confirming zygotic viability selection; vQTL are predominantly expressed before the juvenile stage (90%), mostly at metamorphosis (50%). We estimate that, altogether, selection on vQTL caused 96% mortality in these families, accounting for nearly all of the actual mortality. Thus, genetic load causes substantial mortality in inbred Pacific oysters, particularly during metamorphosis, a critical developmental transition warranting further investigation. PMID:21940682

  12. Context-dependent impacts of a non-native ecosystem engineer, the Pacific oyster Crassostrea gigas.

    PubMed

    Padilla, Dianna K

    2010-08-01

    The introduction of non-native species represents unprecedented large-scale experiments that allow us to examine ecological systems in ways that would otherwise not be possible. Invasion by novel ecological types into a community can press a system beyond the bounds normally seen and can reveal community interactions, local drivers and limits within systems that are otherwise hidden by coevolution and a long evolutionary history among local players, as well as local adaptation of species. The success of many invaders is attributed to their ability to thrive in a wide range of habitat types and physical conditions, setting the stage for direct examination of ecological impacts of a species across a range of habitat and community contexts. Bivalves are well-known ecosystem engineers, especially oysters, which are the target of wild-caught fisheries and aquaculture. The Pacific oyster, Crassostrea gigas, is grown worldwide for aquaculture, and is presently invading shores on virtually every continent. As a consequence, this non-native species is having large impacts on many systems, but the types of impacts are system specific, and greatly depend on substrate type, how physiologically stressful the environment is for intertidal zone species, and the presence of native engineering species. A novel type of engineering effect is identified for this non-native species, whereby it alters not only the physical environment, but also the thermal environment of the community it invades. The impacts of engineering by this non-native species will depend not only on whether it facilitates or inhibits species but also on the trophic level and ecological role of the species affected, and whether similar ecological types are found within the system.

  13. 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.

  14. Gene expression profiling of genetically determined growth variation in bivalve larvae (Crassostrea gigas).

    PubMed

    Meyer, E; Manahan, D T

    2010-03-01

    Growth rates in animals are governed by a wide range of biological factors, many of which remain poorly understood. To identify the genes that establish growth differences in bivalve larvae, we compared expression patterns in contrasting phenotypes (slow- and fast-growth) that were experimentally produced by genetic crosses of the Pacific oyster Crassostrea gigas. Based on transcriptomic profiling of 4.5 million cDNA sequence tags, we sequenced and annotated 181 cDNA clones identified by statistical analysis as candidates for differential growth. Significant matches were found in GenBank for 43% of clones (N=78), including 34 known genes. These sequences included genes involved in protein metabolism, energy metabolism and regulation of feeding activity. Ribosomal protein genes were predominant, comprising half of the 34 genes identified. Expression of ribosomal protein genes showed non-additive inheritance - i.e. expression in fast-growing hybrid larvae was different from average levels in inbred larvae from these parental families. The expression profiles of four ribosomal protein genes (RPL18, RPL31, RPL352 and RPS3) were validated by RNA blots using additional, independent crosses from the same families. Expression of RPL35 was monitored throughout early larval development, revealing that these expression patterns were established early in development (in 2-day-old larvae). Our findings (i) provide new insights into the mechanistic bases of growth and highlight genes not previously considered in growth regulation, (ii) support the general conclusion that genes involved in protein metabolism and feeding regulation are key regulators of growth, and (iii) provide a set of candidate biomarkers for predicting differential growth rates during animal development.

  15. 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

  16. Bioconcentration of sediment-associated fluoranthene by the filter-feeding bivalve mollusk, Crassostrea virginica

    SciTech Connect

    Siewicki, T.C.; Chandler, G.T.

    1995-12-31

    Eastern oysters (Crassostrea virginica) were continuously exposed to suspended {sup 14}C-fluoranthene spiked-sediment for either: (1) five days followed by 24 days deputation, or (2) 28 days exposure. Sediment less than 63 um contained fluoranthene concentrations one or ten times that measured at suburbanized sites in southeastern estuaries (133 or 1,300 ng/g). The data were evaluated both raw and normalized for tissue lipid and sediment organic carbon concentrations. Uptake rate constants were estimated using non-linear regression methods. Depuration rate constants were estimated by linear regression of the deputation phase following five-days exposure and as the second partial derivative of the non-linear regression for the 28-day exposures. Uptake and deputation rate constants, bioconcentration factors and half-lives were similar regardless of exposure time, sediment fluoranthene concentration or use of data normalization. Uptake and deputation rate constants, bioconcentration factors and half-lives (days) were similar and low for all experiments, ranging from 0.02 to 0.10, 0.14 to 0.30, 0.09 to 0.46, and 2.4 to 5.0, respectively. Degradation by the mixed function oxidase system is not expected in oysters allowing the use of radiotracers for measuring very low concentrations of fluoranthene. The results suggest that short-term exposures followed by deputation are effective for estimating kinetic rate constants and that normalization provides little benefit in these controlled studies. The results further show that bioconcentration of sediment-associated fluoranthene, and possibly other polycyclic aromatic hydrocarbons, is very low compared to either dissolved forms or levels commonly used in regulatory actions.

  17. First evidence of laccase activity in the Pacific oyster Crassostrea gigas.

    PubMed

    Luna-Acosta, Andrea; Rosenfeld, Eric; Amari, Myriam; Fruitier-Arnaudin, Ingrid; Bustamante, Paco; Thomas-Guyon, Hélène

    2010-04-01

    Phenoloxidases (POs) are a family of enzymes including tyrosinases, catecholases and laccases, which play an important role in immune defence mechanisms in various invertebrates. The aim of this study was to thoroughly identify the PO-like activity present in the hemolymph of the Pacific oyster Crassostrea gigas, by using different substrates (i.e. dopamine and p-phenylenediamine, PPD) and different PO inhibitors. In order to go deeper in this analysis, we considered separately plasma and hemocyte lysate supernatant (HLS). In crude plasma, oxygraphic assays confirmed the presence of true oxidase activities. Moreover, the involvement of peroxidase(s) was excluded. In contrast to other molluscs, no tyrosinase-like activity was detected. With dopamine as substrate, PO-like activity was inhibited by the PO inhibitors tropolone, phenylthiourea (PTU), salicylhydroxamic acid and diethyldithio-carbamic acid, by a specific inhibitor of tyrosinases and catecholases, i.e. 4-hexylresorcinol (4-HR), and by a specific inhibitor of laccases, i.e. cetyltrimethylammonium bromide (CTAB). With PPD as substrate, PO-like activity was inhibited by PTU and CTAB. In precipitated protein fractions from plasma, and with dopamine and PPD as substrates, PTU and 4-HR, and PTU and CTAB inhibited PO-like activity, respectively. In precipitated protein fractions from hemocyte lysate supernatant, PTU and CTAB inhibited PO-like activity, independently of the substrate. Taken together, these results suggest the presence of both catecholase- and laccase-like activities in plasma, and the presence of a laccase-like activity in HLS. To the best of our knowledge, this is the first time that a laccase-like activity is identified in a mollusc by using specific substrates and inhibitors for laccase, opening new perspectives for studying the implication of this enzyme in immune defence mechanisms of molluscs of high economic value such as C. gigas. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Ontogeny and water temperature influences the antiviral response of the Pacific oyster, Crassostrea gigas.

    PubMed

    Green, Timothy J; Montagnani, Caroline; Benkendorff, Kirsten; Robinson, Nick; Speck, Peter

    2014-01-01

    Disease is caused by a complex interaction between the pathogen, environment, and the physiological status of the host. Determining how host ontogeny interacts with water temperature to influence the antiviral response of the Pacific oysters, Crassostrea gigas, is a major goal in understanding why juvenile Pacific oysters are dying during summer as a result of the global emergence of a new genotype of the Ostreid herpesvirus, termed OsHV-1 μvar. We measured the effect of temperature (12 vs 22 °C) on the antiviral response of adult and juvenile C. gigas injected with poly I:C. Poly I:C up-regulated the expression of numerous immune genes, including TLR, MyD88, IκB-1, Rel, IRF, MDA5, STING, SOC, PKR, Viperin and Mpeg1. At 22 °C, these immune genes showed significant up-regulation in juvenile and adult oysters, but the majority of these genes were up-regulated 12 h post-injection for juveniles compared to 26 h for adults. At 12 °C, the response of these genes was completely inhibited in juveniles and delayed in adults. Temperature and age had no effect on hemolymph antiviral activity against herpes simplex virus (HSV-1). These results suggest that oysters rely on a cellular response to minimise viral replication, involving recognition of virus-associated molecular patterns to induce host cells into an antiviral state, as opposed to producing broad-spectrum antiviral compounds. This cellular response, measured by antiviral gene expression of circulating hemocytes, was influenced by temperature and oyster age. We speculate whether the vigorous antiviral response of juveniles at 22 °C results in an immune-mediated disorder causing mortality.

  19. 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.

  20. Hemolymph chemistry and histopathological changes in Pacific oysters (Crassostrea gigas) in response to low salinity stress.

    PubMed

    Knowles, Graeme; Handlinger, Judith; Jones, Brian; Moltschaniwskyj, Natalie

    2014-09-01

    This study described seasonal differences in the histopathological and hemolymph chemistry changes in different family lines of Pacific oysters, Crassostrea gigas, in response to the stress of an abrupt change to low salinity, and mechanical grading. The most significant changes in pallial cavity salinity, hemolymph chemistry and histopathological findings occurred in summer at low salinity. In summer (water temperature 18°C) at low salinity, 9 (25.7% of full salinity), the mean pallial cavity salinity in oysters at day 3 was 19.8±1.6 (SE) and day 10 was 22.8±1.6 (SE) lower than oysters at salinity 35. Associated with this fall in pallial cavity salinity, mean hemolymph sodium for oysters at salinity 9 on day 3 and 10 were 297.2mmol/L±20(SE) and 350.4mmol/L±21.3(SE) lower than oysters at salinity 35. Similarly mean hemolymph potassium in oysters held at salinity 9 at day 3 and 10 were 5.6mmol/L±0.6(SE) and 7.9mmol/L±0.6 (SE) lower than oysters at salinity 35. These oysters at low salinity had expanded intercellular spaces and significant intracytoplasmic vacuolation distending the cytoplasm of epithelial cells in the alimentary tract and kidney and hemocyte infiltrate (diapedesis) within the alimentary tract wall. In contrast, in winter (water temperature 8°C) oyster mean pallial cavity salinity only fell at day 10 and this was by 6.0±0.6 (SE) compared to that of oysters at salinity 35. There were limited histopathological changes (expanded intercellular spaces and moderate intracytoplasmic vacuolation of renal epithelial cells) in these oysters at day 10 in low salinity. Mechanical grading and family line did not influence the oyster response to sudden low salinity. These findings provide additional information for interpretation of non-lethal, histopathological changes associated with temperature and salinity variation.

  1. Seasonality in the infection and invasion of Marteilioides chungmuensis in the Pacific oyster Crassostrea gigas.

    PubMed

    Tun, Kay Lwin; Shimizu, Yasuko; Yamanoi, Hideo; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2008-07-07

    The protozoan parasite Marteilioides chungmuensis causes irregular enlargement of the ovary in the Pacific oyster Crassostrea gigas. The parasite invades the oyster through the epithelial tissue of the labial palp, replicates in the connective tissue, and then moves to the gonad, producing spores inside the oocytes. In this study the seasonality and invasion period of the parasite into the host was investigated over a 1 yr cycle. Uninfected 1 and 0 yr old (spat) oysters were placed in an epizootic area every month from July 2004 to July 2005 and September 2005 to March 2006, respectively, and left for 1 mo. Labial palps and gonad were sampled monthly and examined for infection by nested PCR and histological observations. Prevalence of infection detected by PCR was 70% or higher from August to October, but declined sharply in November and reached 7% or lower from February to April. To explain the low detection rate in winter, 1 yr old uninfected oysters were placed in an epizootic area in winter (water temperature: 8 to 10 degrees C) for 2 wk and then transferred to M. chungmuensis-free seawater at 24 degrees C. Although prevalence of infection was ca. 7% before transfer to heated seawater, levels of 87% were detected after 1 wk. After a 3 wk exposure to heated seawater, parasites were found in host oocytes by histological observation. It was concluded that the low prevalence in winter was due to insufficient replication of M. chungmuensis at low seawater temperatures, resulting in levels not detectable by nested PCR, and not to the absence of invasion.

  2. Quantitative trait locus analysis of stage-specific inbreeding depression in the Pacific oyster Crassostrea gigas.

    PubMed

    Plough, Louis V; Hedgecock, Dennis

    2011-12-01

    Inbreeding depression and genetic load have been widely observed, but their genetic basis and effects on fitness during the life cycle remain poorly understood, especially for marine animals with high fecundity and high, early mortality (type-III survivorship). A high load of recessive mutations was previously inferred for the Pacific oyster Crassostrea gigas, from massive distortions of zygotic, marker segregation ratios in F(2) families. However, the number, genomic location, and stage-specific onset of mutations affecting viability have not been thoroughly investigated. Here, we again report massive distortions of microsatellite-marker segregation ratios in two F(2) hybrid families, but we now locate the causative deleterious mutations, using a quantitative trait locus (QTL) interval-mapping model, and we characterize their mode of gene action. We find 14-15 viability QTL (vQTL) in the two families. Genotypic frequencies at vQTL generally suggest selection against recessive or partially recessive alleles, supporting the dominance theory of inbreeding depression. No epistasis was detected among vQTL, so unlinked vQTL presumably have independent effects on survival. For the first time, we track segregation ratios of vQTL-linked markers through the life cycle, to determine their stage-specific expression. Almost all vQTL are absent in the earliest life stages examined, confirming zygotic viability selection; vQTL are predominantly expressed before the juvenile stage (90%), mostly at metamorphosis (50%). We estimate that, altogether, selection on vQTL caused 96% mortality in these families, accounting for nearly all of the actual mortality. Thus, genetic load causes substantial mortality in inbred Pacific oysters, particularly during metamorphosis, a critical developmental transition warranting further investigation.

  3. 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

  4. Genetic by environmental variation but no local adaptation in oysters (Crassostrea virginica).

    PubMed

    Hughes, A Randall; Hanley, Torrance C; Byers, James E; Grabowski, Jonathan H; Malek, Jennafer C; Piehler, Michael F; Kimbro, David L

    2017-01-01

    Functional trait variation within and across populations can strongly influence population, community, and ecosystem processes, but the relative contributions of genetic vs. environmental factors to this variation are often not clear, potentially complicating conservation and restoration efforts. For example, local adaptation, a particular type of genetic by environmental (G*E) interaction in which the fitness of a population in its own habitat is greater than in other habitats, is often invoked in management practices, even in the absence of supporting evidence. Despite increasing attention to the potential for G*E interactions, few studies have tested multiple populations and environments simultaneously, limiting our understanding of the spatial consistency in patterns of adaptive genetic variation. In addition, few studies explicitly differentiate adaptation in response to predation from other biological and environmental factors. We conducted a reciprocal transplant experiment of first-generation eastern oyster (Crassostrea virginica) juveniles from six populations across three field sites spanning 1000 km in the southeastern Atlantic Bight in both the presence and absence of predation to test for G*E variation in this economically valuable and ecologically important species. We documented significant G*E variation in survival and growth, yet there was no evidence for local adaptation. Condition varied across oyster cohorts: Offspring of northern populations had better condition than offspring from the center of our region. Oyster populations in the southeastern Atlantic Bight differ in juvenile survival, growth, and condition, yet offspring from local broodstock do not have higher survival or growth than those from farther away. In the absence of population-specific performance information, oyster restoration and aquaculture may benefit from incorporating multiple populations into their practices.

  5. Effects of Potential Therapeutic Agents on Copper Accumulations in Gill of Crassostrea virginica

    PubMed Central

    Luxama, Juan D.; Carroll, Margaret A.; Catapane, Edward J.

    2010-01-01

    Copper is an essential trace element for organisms, but when in excess, copper’s redox potential enhances oxyradical formation and increases cellular oxidative stress. Copper is a major pollutant in Jamaica Bay and other aquatic areas. Bivalves are filter feeders that accumulate heavy metals and other pollutants from their environment. Previously it was determined that seed from the bivalve Crassostrea virginica, transplanted from an oyster farm to Jamaica Bay readily accumulated copper and other pollutants into their tissues. In the present study we utilized Atomic Absorption Spectrometry to measure the uptake of copper into C. virginica gill in the presence and absence of three potential copper -blocking agents: diltiazem, lanthanum, and p-aminosalicyclic acid. Diltiazem and lanthanum are known calcium-channel blockers and p-aminosalicylic acid is an anti-infammarory agent with possible metal chelating properties. We also used the DMAB-Rhodanine histochemistry staining technique to confirm that copper was entering gill cells. Our result showed that diltiazem and p-aminosalicyclic acid reduced copper accumulations in the gill, while lanthanum did not. DMAB-Rhodanine histochemistry showed enhanced cellular copper staining in copper-treated samples and further demonstrated that diltiazem was able to reduce copper uptake. The accumulation of copper into oyster gill and its potential toxic effects could be of physiological significance to the growth and long term health of oysters and other marine animals living in a copper polluted environment. Identifying agents that block cellular copper uptake will further the understanding of metal transport mechanisms and may be beneficial in the therapeutic treatment of copper toxicity in humans. PMID:21841975

  6. 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.

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

    PubMed

    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 Rf of about 0.7 and contains relatively little Zn, as previously reported. 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, but these may be largely removed depending upon whether the protein is denatured and carboxymethylated prior to analysis. 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. In contrast with mammals, CdBP accounts for only about 30% of the total cell Cd burden in these tissues. Cu displacement of Cd from the protein is a particular problem during the summer spawning season and appears to stem from altered Cu metabolism during this period. 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.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Cellular responses of eastern oysters, Crassostrea virginica, to titanium dioxide nanoparticles.

    PubMed

    Johnson, Brian D; Gilbert, Samantha L; Khan, Bushra; Carroll, David L; Ringwood, Amy H

    2015-10-01

    Because of the continued development and production of a variety of nanomaterials and nanoparticles, their uptake and effects on the biota of marine ecosystems must be investigated. Filter feeding bivalve molluscs are highly adapted for capturing particles from the external environment and readily internalize nano- and micro-sized particles through endocytosis, so they are commonly used as valuable indicator species for nanoparticle studies. In these studies, adult eastern oysters, Crassostrea virginica, were exposed to a range of titanium dioxide nanoparticle (TiO2-NP) concentrations (5, 50, 500, and 5000 μg/L) in conjunction with natural sunlight. Isolated hepatopancreas tissues were also exposed to the same TiO2-NP concentrations using particles exposed to similar light and dark conditions. Dose-dependent decreases in lysosomal stability were observed in the adult oyster studies as well as in the isolated tissues, at exposures as low as 50 μg/L. Titanium accumulation in isolated hepatopancreas tissue studies was directly correlated to lysosomal destabilization. Based on measurements of lipid peroxidation as an indicator of oxidative stress, TiO2-NPs toxicity was not related to increased ROS production over the short-term course of these exposures. Analysis of particle size using dynamic light scattering (DLS) indicated that concentration had a significant impact on agglomeration rates, and the small agglomerates as well as individual particles are readily processed by oysters. Overall, this study illustrates that low concentrations of TiO2-NPs may cause sublethal toxicity on oysters, which might be enhanced under natural sunlight conditions. In estuarine environments, where these nanomaterials are likely to accumulate, agglomeration rates, interaction with organics, and responses to sunlight are critical in determining the extent of their bioreactivity and biological impacts.

  9. 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.

  10. Effects of phenanthrene on early development of the Pacific oyster Crassostrea gigas (Thunberg, 1789).

    PubMed

    Nogueira, Diego J; Mattos, Jacó J; Dybas, Patrick R; Flores-Nunes, Fabrıcio; Sasaki, Silvio Tarou; Taniguchi, Satie; Schmidt, Éder C; Bouzon, Zenilda L; Bícego, Márcia C; Melo, Claudio M R; Toledo-Silva, Guilherme; Bainy, Afonso C D

    2017-10-01

    Phenanthnere (PHE) is a polycyclic aromatic hydrocarbon continuously discarded in the marine environment and bioavailable to many aquatic species. Although studies about PHE toxicity have been documented for adult oysters, the effects on early developmental stages are poorly characterized in bivalves. In this study, the effects of PHE (0.02 and 2.0μg.L(-1)) were evaluated on the embryogenesis and larval development of Crassostrea gigas. Toxicity bioassays, growth and deformities assessment, analysis of shell calcium abundance and transcript levels of genes related to xenobiotic biotransformation (CYP2AU2, CYP30C1), immune system (Cg-Tal) and tissue growth and shell formation (Ferritin, Insulin-like, Cg-Try, Calmodulin and Nacrein) were assayed in D-shape larvae after 24h of PHE exposure. At the highest concentration (2.0μg.L(-1)), PHE decreased the frequency of normal development (19.7±2.9%) and shell size (53.5±2.8mm). Developmental deformities were mostly related to abnormal mantle and shell formation. Lower calcium levels in oyster shells exposed to PHE 2.0μg.L(-1) were observed, suggesting effects on shell structure. At this same PHE concentration, CYP30C1, Cg-Tal, Cg-Tyr, Calmodulin were upregulated and CYP2AU2, Ferritin, Nacrein, and Insulin-Like were downregulated compared to control larvae. At the lowest PHE concentration (0.02μg.L(-1)), it was observed a minor decrease in normal larval development (89,6±6%) and the remaining parameters were not affected. This is the first study to provide evidences that exposure to PHE can affect early oyster development at the molecular and morphological levels, possibly threatening this bivalve species. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Low sensitivity of reproductive life-stages in the Pacific oyster (Crassostrea gigas) to abamectin.

    PubMed

    Falkenberg, Laura J; Wrange, Anna-Lisa; Kinnby, Alexandra; Havenhand, Jon N; Lockyer, Antony; Styan, Craig A

    2017-09-01

    Hard surfaces submerged in the marine environment often become colonised by macro-organisms unless the surfaces have some form of biofouling protection. While protective paints that contain tributyltin or copper work well to prevent biofouling, release of these materials into the environment has been shown to have wider negative impacts. Consequently, new low-release antifouling paints are being developed with alternative active ingredients, such as avermectins, yet little is known about their potential effects on non-target organisms in marine environments. Here we investigated the toxicity of a key avermectin, specifically abamectin, on several aspects of reproduction (sperm motility, fertilisation success, early larval development) in the Pacific oyster, Crassostrea gigas. Oyster reproduction was generally insensitive to the low concentrations of abamectin, although greater concentrations of abamectin did negatively affect all three endpoints - LOECs were 1000 μg l(-1), 500 μg l(-1), and 100 μg l(-1) abamectin for sperm motility, fertilisation success, and larval development, respectively. A similar pattern was found in the EC50s of the three endpoints (mean ± SE) 934 ± 59 μg l(-1), 1076.26 ± 725.61 μg l(-1), and 140 ± 78 μg l(-1) abamectin (sperm motility, fertilisation success, and larval development, respectively). Together, these results clearly indicate that of the three endpoints considered, larval development was more sensitive to abamectin (lower LOEC, EC50) than fertilisation success and sperm motility. Although more data are needed from a wider range of marine species and environments to fully assess potential toxicity effects on non-target organisms, our results highlight the potential utility of abamectin in low-release antifouling paints. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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. © 2015. Published by The Company of Biologists Ltd.

  13. 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

  14. Heterologous expression of the Crassostrea gigas (Pacific oyster) alternative oxidase in the yeast Saccharomyces cerevisiae.

    PubMed

    Robertson, Aaron; Schaltz, Kyle; Neimanis, Karina; Staples, James F; McDonald, Allison E

    2016-10-01

    Alternative oxidase (AOX) is a terminal oxidase within the inner mitochondrial membrane (IMM) present in many organisms where it functions in the electron transport system (ETS). AOX directly accepts electrons from ubiquinol and is therefore capable of bypassing ETS Complexes III and IV. The human genome does not contain a gene coding for AOX, so AOX expression has been suggested as a gene therapy for a range of human mitochondrial diseases caused by genetic mutations that render Complex III and/or IV dysfunctional. An effective means of screening mutations amenable to AOX treatment remains to be devised. We have generated such a tool by heterologously expressing AOX from the Pacific oyster (Crassostrea gigas) in the yeast Saccharomyces cerevisiae under the control of a galactose promoter. Our results show that this animal AOX is monomeric and is correctly targeted to yeast mitochondria. Moreover, when expressed in yeast, Pacific oyster AOX is a functional quinol oxidase, conferring cyanide-resistant growth and myxothiazol-resistant oxygen consumption to yeast cells and isolated mitochondria. This system represents a high-throughput screening tool for determining which Complex III and IV genetic mutations in yeast will be amenable to AOX gene therapy. As many human genes are orthologous to those found in yeast, our invention represents an efficient and cost-effective way to evaluate viable research avenues. In addition, this system provides the opportunity to learn more about the localization, structure, and regulation of AOXs from animals that are not easily reared or manipulated in the lab.

  15. The nuclear receptor gene family in the Pacific oyster, Crassostrea gigas, contains a novel subfamily group.

    PubMed

    Vogeler, Susanne; Galloway, Tamara S; Lyons, Brett P; Bean, Tim P

    2014-05-15

    Nuclear receptors are a superfamily of transcription factors important in key biological, developmental and reproductive processes. Several of these receptors are ligand- activated and through their ability to bind endogenous and exogenous ligands, are potentially vulnerable to xenobiotics. Molluscs are key ecological species in defining aquatic and terrestrial habitats and are sensitive to xenobiotic compounds in the environment. However, the understanding of nuclear receptor presence, function and xenobiotic disruption in the phylum Mollusca is limited. Here, forty-three nuclear receptor sequences were mined from the genome of the Pacific oyster, Crassostrea gigas. They include members of NR0-NR5 subfamilies, notably lacking any NR6 members. Phylogenetic analyses of the oyster nuclear receptors have been conducted showing the presence of a large novel subfamily group not previously reported, which is named NR1P. Homologues to all previous identified nuclear receptors in other mollusc species have also been determined including the putative heterodimer partner retinoid X receptor, estrogen receptor and estrogen related receptor. C. gigas contains a highly diverse set of nuclear receptors including a novel NR1 group, which provides important information on presence and evolution of this transcription factor superfamily in invertebrates. The Pacific oyster possesses two members of NR3, the sex steroid hormone receptor analogues, of which there are 9 in humans. This provides increasing evidence that steroid ligand specific expansion of this family is deuterostome specific. This new knowledge on divergence and emergence of nuclear receptors in C. gigas provides essential information for studying regulation of molluscan gene expression and the potential effects of xenobiotics.

  16. Epizootiology of Perkinsus marinus, parasite of the pleasure oyster Crassostrea corteziensis, in the Pacific coast of Mexico.

    PubMed

    Cáceres-Martínez, Jorge; Madero-López, Luis Humberto; Padilla-Lardizábal, Gloria; Vásquez-Yeomans, Rebeca

    2016-09-01

    The protozoan parasite Perkinsus marinus is the etiological agent of "dermo disease". This pathogen is considered by the World Organization for Animal Health (OIE) as reportable due to the high mortalities that it produces in the eastern oyster Crassostrea virginica in the US. In 2006, this parasite was detected in the pleasure oyster Crassostrea corteziensis in Nayarit on the Pacific coast of Mexico, indicating a new host and an extension of its known distribution. Epizootiological data of P. marinus in the pleasure oyster are unknown. With the objective of determining the prevalence and intensity in relation with temperature and salinity throughout time, as well as for studying interactions of host size and sex with the parasite, a monthly sampling was carried out in two aquaculture sites of Nayarit from 2007 to 2014. A total of 7700 oysters were analyzed. In both localities, prevalence was low in winter (<6%) when temperature and salinity fluctuated around 24°C and 33, respectively; and the highest prevalence values occurred during summer (37%) when temperature and salinity were around 30°C and 20, respectively. Infection intensity increased in summer, but severe cases remained on average <10%. Larger oysters showed the highest prevalence and intensity, and higher prevalence were generally observed in females. No unusual mortalities directly related with P. marinus were observed. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. High pressure treatment changes spoilage characteristics and shelf life of Pacific oysters ( Crassostrea gigas) during refrigerated storage

    NASA Astrophysics Data System (ADS)

    Cao, Rong; Zhao, Ling; Liu, Qi

    2017-04-01

    The effects of high pressure (HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters ( Crassostrea gigas) during refrigerated storage were studied. Results showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle, pressures higher than 350 MPa caused excessive release as the shells of oysters were broken, thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of shells. HP treatment (300 MPa, 2 min) was proper for the shucking of Pacific oyster ( Crassostrea gigas) in China. This treatment caused no organoleptic disadvantage. Moreover, HP treatment resulted in obvious differences in biochemical spoilage indicators (pH, TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during storage. HP treatment (300 MPa, 2 min) also led to a reduction of aerobic bacterial count (APC) by 1.27 log cycles. Furthermore, the APC values of oysters treated by HP were always lower than those of the control samples during storage. Based on the organoleptic, biochemical and microbiological indicators, shelf life of 6-8 d for control and 12 d for HP-treated oysters could be expected. HP treatment showed great potential in oyster processing and preservation.

  18. Molecular Analysis of Atypical Family 18 Chitinase from Fujian Oyster Crassostrea angulata and Its Physiological Role in the Digestive System.

    PubMed

    Yang, Bingye; Zhang, Mingming; Li, Lingling; Pu, Fei; You, Weiwei; Ke, Caihuan

    2015-01-01

    Chitinolytic enzymes have an important physiological significance in immune and digestive systems in plants and animals, but chitinase has not been identified as having a role in the digestive system in molluscan. In our study, a novel chitinase homologue, named Ca-Chit, has been cloned and characterized as the oyster Crassostrea angulate. The 3998bp full-length cDNA of Ca-Chit consisted of 23bp 5-UTR, 3288 ORF and 688bp 3-UTR. The deduced amino acids sequence shares homologue with the chitinase of family 18. The molecular weight of the protein was predicted to be 119.389 kDa, with a pI of 6.74. The Ca-Chit protein was a modular enzyme composed of a glycosyl hydrolase family 18 domain, threonine-rich region profile and a putative membrane anchor domain. Gene expression profiles monitored by quantitative RT-PCR in different adult tissues showed that the mRNA of Ca-Chit expressed markedly higher visceral mass than any other tissues. The results of the whole mount in-situ hybridization displayed that Ca-Chit starts to express the visceral mass of D-veliger larvae and then the digestive gland forms a crystalline structure during larval development. Furthermore, the adult oysters challenged by starvation indicated that the Ca-Chit expression would be regulated by feed. All the observations made suggest that Ca-Chit plays an important role in the digestive system of the oyster, Crassostrea angulate.

  19. Impacts of ocean acidification on gene expression and biomineralisation in the Pacific oyster Crassostrea gigas Thunberg, 1793

    NASA Astrophysics Data System (ADS)

    Bagusche, F.; Pouvreau, S.; Trueman, C.; Long, S.; Hauton, C.

    2012-04-01

    The published evidence of impacts of ocean acidification and on marine calcifiers has emphasized the need to understand the molecular mechanisms of biomineralisation. Crassostrea gigas is an ideal organism to examine these processes as: 1) the hatchery rearing of larval stages is well constrained, 2) studies have established an ontogenetic switch in deposition of carbonate polymorphs from aragonite in larval shells to calcite in adults and 3) it is a globally-important commercial species. Research summarized in this presentation will identify some of the molecular mechanisms involved in calcification processes during ontogeny of Crassostrea gigas, as well as possible impacts of changes in environmental conditions such as temperature and pH. Data will be presented from a quantitative real-time PCR study of the changes in gene expression during development in different environments. Additionally scanning electron microscopy and infrared spectroscopy analyses of shell microstructures and composition will be summarised to correlate changes in gene expression with end-point differences in shell structure. Preliminary results suggest that changes in the environmental conditions lead to differences in expression patterns of genes involved in biomineralisation processes. The combined effects of ambient seawater temperature and low pH show the greatest negative effect on larval shell development, identified as malformations, eroded shell surfaces and a significant decrease in shell size. However, the effect of higher seawater temperature seems to amend the effects of ocean acidification on larval shell development.

  20. Bioaccumulation of heavy metals in mullet (Mugil cephalus) and oyster (Crassostrea madrasensis) from Pulicat lake, south east coast of India.

    PubMed

    Laxmi Priya, S; Senthilkumar, B; Hariharan, G; Paneer Selvam, A; Purvaja, R; Ramesh, R

    2011-03-01

    The accumulation of six heavy metals (Cr, Cd, Cu, Zn, Pb and Ni) in sediment, water and in tissue parts of Mugil cephalus and Crassostrea madrasensis was studied in two locations of Pulicat lake, Southeast coast of India, which receives considerable quantity of effluents from industries located in North Chennai coastal region. The results reveal that the metal concentration in water is decreasing in the following order of Zn > Ni > Cu > Cr > Pb > Cd both in lake and barmouth and highest concentration was observed for Zn (32.5 μg L(-1) in lake and 25.2 μg L(-1) in bar mouth). Metals were highly concentrated in sediments when compared to water and biota. Metals abundance in sediments has following sequential order of Cr > Ni > Zn > Cu > Pb > Cd and the accumulation pattern in barmouth showed minor variation indicating the following pattern of Zn > Ni > Cr > Cu > Pb > Cd. The geoaccumulation index (I(geo)) for Pulicat lake sediments indicate that the sediments are extremely contaminated with Cd and moderately contaminated with Cu and Ni. Bioaccumulation of heavy metals in Mugil cephalus and Crassostrea madrasensis showed marked differences in the accumulation patterns. It is observed that Zn, Cu and Pb are accumulated in elevated concentrations in various parts of the fish and oyster when compared with other metals.

  1. c-Jun N-terminal kinase (JNK) is involved in immune defense against bacterial infection in Crassostrea hongkongensis.

    PubMed

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

    2017-02-01

    c-Jun N-terminal kinase (JNK) is a universal and essential subgroup of the mitogen-activated protein kinase (MAPK) superfamily, which is highly conserved from yeast to mammals and functions in a variety of physiological and pathological processes. In this study, we report the first oyster JNK gene homolog (ChJNK) and its biological functions in the Hong Kong oyster Crassostrea hongkongensis. The ChJNK protein consists of 383 amino acids and contains a conserved serine/threonine protein kinase (S_TKc) domain with a typical TPY motif. Phylogenetic analysis revealed that ChJNK shared a close evolutionary relationship with Crassostrea gigas JNK. Quantitative RT-PCR analyses revealed broad expression patterns of ChJNK mRNA in various adult tissues and different embryonic and larval stages of C. hongkongensis. When exposed to Vibrio alginolyticus or Staphylococcus haemolyticus, ChJNK mRNA expression levels were significantly up-regulated in the hemocytes and gills in a time-dependent manner. Additionally, subcellular localization studies that ChJNK is a cytoplasm-localized protein, and that its overexpression could significantly enhance the transcriptional activities of AP-1-Luc in HEK293T cells. In summary, this study provided the first experimental demonstration that oysters possess a functional JNK that participates in host defense against bacterial infection in C. hongkongensis.

  2. Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios

    PubMed Central

    Abi-Khalil, Celina; Lopez-Joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-Luc

    2016-01-01

    The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events. PMID:26784228

  3. 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.

  4. 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

  5. Two rare antioxidative prenylated terpenoids from loop-root Asiatic mangrove Rhizophora mucronata (Family Rhizophoraceae) and their activity against pro-inflammatory cyclooxygenases and lipoxidase.

    PubMed

    Raola, Vamshi Krishna; Chakraborty, Kajal

    2017-02-01

    Two new biogenic prenylated terpenoids were isolated from the methanol extract of Rhizophora mucronata. The extended C20 sesquiterpenoid with prenylated guaiane framework was characterised as (4E, 8Z)-3, 3a, 6, 7-tetrahydro-3, 9-dimethyl-5-(6-methylheptan-2-yl) cycloocta[b]furan-2-(9aH)-one (1). (35E)-1,2,3,5,6,6-icosahydro-4,4,8b,10,14,17,20,20-octamethylpicen-3-yl-34,35-dimethyloct-31-enoate (2) represents the first example of naturally occurring C40 prenylated oleanane-type triterpenoid, whereas one 4,5-dimethyloct-5-enoate side chain remains attached at C-3 position of the oleanane framework formed by the E-ring closure of C30 saccharide moiety. The structures of the compounds were elucidated using NMR and mass spectrometric analysis. Compound 1 was found to have significantly greater antioxidant activities (IC50 ~ 0.75 mg/mL) compared to 2 (IC50 > 0.80 mg/mL). No significant differences in anti-cyclooxygenase-2 of these compounds were discernable (IC50 0.8 - 0.9 mg/mL), whilst compound 1 showed greater anti-5-lipoxidase activities (IC50 ~ 0.8 mg/mL) those that of 2 (IC50 0.96 mg/mL). Bioactivities of the prenylated terpenoids were inversely proportional to lipophilic and bulk descriptors.

  6. 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.

  7. Habitat change by the formation of alien Crassostrea-reefs in the Wadden Sea and its role as feeding sites for waterbirds

    NASA Astrophysics Data System (ADS)

    Markert, Alexandra; Esser, Wiebke; Frank, Dietrich; Wehrmann, Achim; Exo, Klaus-Michael

    2013-10-01

    Non-indigenous Pacific oysters (Crassostrea gigas) have been invading the central Wadden Sea since 1998, predominantly settling on intertidal blue mussel (Mytilus edulis) beds which are increasingly transformed into Crassostrea-reefs. Pacific oysters are strong ecosystem engineers and the habitat change is considered to be a threat for waterbirds losing important feeding sites in the intertidal of the Wadden Sea. This study has increased our understanding of the use of foraging habitats by birds according to changing food resources. During the spring and autumn migration period in 2007, we recorded bird densities at two reef types varying in Pacific oyster density and at the adjacent sand flat as a reference site. We also recorded feeding behaviour, choice of prey and assessed peck and intake rate of three target species: Eurasian oystercatcher Haematopus ostralegus, Eurasian curlew Numenius arquata and European herring gull Larus argentatus. To evaluate the use of the Crassostrea-reef in the central Wadden Sea, we compared bird densities of the target species at different intertidal feeding habitats in various regions and compared the biomass intake of Eurasian oystercatcher feeding on different prey species. We show that Eurasian oystercatcher and Eurasian curlew have adapted to the new situation and learned to exploit the food supply offered by Crassostrea-reefs. While foraging mainly on Pacific oysters, Eurasian oystercatchers attained sustainable intake rates even though food resource at dense reef during autumn was very poor due to a lack in harvestable oysters. Consolidation of reefs limits the accessibility of prey for Eurasian oystercatchers whereas a successful recruitment of Pacific oysters enhances the suitability of the habitat. Eurasian curlew was promoted by the engineering effects of the Pacific oyster while feeding extensively on shore crabs at the reefs. In contrast, European herring gulls appear hampered in foraging during low tide and hereby

  8. Persistent free radical ESR signals in marine bivalve tissues. [Electron Spin Resonance (ESR)

    SciTech Connect

    Mehlorn, R.J. . Dept. of Materials Science and Mineral Engineering); Mendez, A.T. ); Higashi, R. . Bodega Marine Lab.); Fan, T. )

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  9. Persistent free radical ESR signals in marine bivalve tissues

    SciTech Connect

    Mehlorn, R.J.; Mendez, A.T.; Higashi, R.; Fan, T.

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  10. Vibrio sonorensis sp. nov. isolated from a cultured oyster Crassostrea gigas.

    PubMed

    González-Castillo, Adrián; Enciso-Ibarra, Julissa; Dubert, Javier; Romalde, Jesús L; Gomez-Gil, Bruno

    2016-11-01

    Strain CAIM 1076(T) was isolated from a cultured oyster Crassostrea gigas in Puerto Peñasco, Sonora state, México. The strain was taxonomically characterised by means of a genomic approach, comprising 16S rRNA gene sequence analysis, multilocus sequence analysis (MLSA), the DNA G+C content and whole genome analyses (ANI and GGDC), and by phenotypic characterisation. Strain CAIM 1076(T) was found to be catalase and oxidase positive, and cells were observed to be motile and facultative anaerobic. Analysis of the almost-complete 16S rRNA gene sequence placed this strain within the genus Vibrio; closely related species were Vibrio maritimus, Vibrio variabilis, Vibrio proteolyticus, and Vibrio nigripulchritudo with similarity values of 98.9, 98.5, 98.1, and 98.0 %, respectively. MLSA of six housekeeping genes (ftsZ, gapA, gyrB, recA, rpoA and topA) was performed with the closely related species. A draft genome sequence of strain CAIM 1076(T) was obtained. The DNA G+C content of this strain was determined to be 44.5 mol %. The genomic similarity values with V. maritimus were 71.6 % (ANIb), 85.1 % (ANIm) and a GGDC value of 20.3 ± 2.3 %; with V. variabilis the genomic similarities were 71.8 % (ANIb), 85.4 % (ANIm) and 20.0 ± 2.3 % (GGDC); with V. proteolyticus, 71.6 % (ANIb), 84.1 % (ANIm) and 18.8 ± 2.2 % (GGDC); and with V. nigripulchritudo, 70.8 % (ANIb), 84.9 % (ANIm) and 20.5 ± 2.3 % (GGDC). These ANI and GGDC values are below the thresholds for the delimitation of prokaryotic species, i.e., 95-96 and 70 %, respectively. Phenotypic characters also showed differences with the closely related species analysed. The results presented here support the description of a novel species, for which the name Vibrio sonorensis sp. nov. is proposed, with strain CAIM 1076(T) (=CECT 9100(T), =DSM 102190(T)) as the type strain.

  11. The immunological capacity in the larvae of Pacific oyster Crassostrea gigas.

    PubMed

    Song, Xiaorui; Wang, Hao; Xin, Lusheng; Xu, Jiachao; Jia, Zhihao; Wang, Lingling; Song, Linsheng

    2016-02-01

    As the immune system has not fully developed during early developmental stages, bivalve larvae are more susceptible for pathogens, which frequently leads to the significant mortality in hatcheries. In the present study, the development of immune system and its response against bacteria challenge were investigated in order to characterize the repertoire of immunological capacity of Pacific oyster Crassostrea gigas during the ontogenesis. The phagocytosis was firstly observed in the early D-veliger larvae (17 hpf), especially in their velum site, which indicated the appearance of functional hemocytes during early D-veliger larvae stage. The whole-mount immunofluorescence assay of three pattern recognition receptors (integrin β-1, caspase-3 and C-type lectin 3) and one immune effector gene (IL17-5) was performed in blastula, early D-veliger and umbo larvae, suggested that velum and digestive gland were the potential sites of immune system in the larvae. The lowest activities of antioxidant enzymes (superoxide dismutase and catalase) and hydrolytic enzyme (lysozyme), as well as descended expression levels of 12 immune genes at the transition between embryogenesis and planktonic, indicated that the larvae at hatching (9 hpf) were in hypo-immunity. While the ascending activities of enzymes and expression levels of seven immune genes during the trochophore stage (15 hpf) suggested the initiation of immune system. The steadily increasing trend of all the 12 candidate genes at the early umbo larvae (120 h) hinted that the immune system was well developed at this stage. After bacterial challenge, some immune recognition (TLR4) and immune effector (IL17-5 and defh2) genes were activated in blastula stage (4 hpf), and other immune genes were up regulated in D-veliger larvae, indicating that the zygotic immune system could respond earlier against the bacterial challenge during its development. These results indicated that the cellular and humoral immune components

  12. Two short peptidoglycan recognition proteins from Crassostrea gigas with similar structure exhibited different PAMP binding activity.

    PubMed

    Yang, Chuanyan; Wang, Lingling; Jia, Zhihao; Yi, Qilin; Xu, Qingsong; Wang, Weilin; Gong, Changhao; Liu, Conghui; Song, Linsheng

    2017-05-01

    Peptidoglycan recognition protein (PGRP) is an essential molecule in innate immunity for both invertebrates and vertebrates, owing to its prominent ability in specifically recognizing bacterial peptidoglycan (PGN) and eliminating the invading bacteria. In the present study, the full length cDNA of two PGRP genes, CgPGRPS2 and CgPGRPS4, were cloned from oyster Crassostrea gigas. Their amino acid sequences both contained one signal peptide, one typical PGRP/amidase domain with conserved catalytic residues responsible for amidase activity (55H, 90Y, 164H, 172C in CgPGRPS2, and 98H, 133Y, 207H, 215C in CgPGRPS4), and specific PGN recognition (84R, 85W, 104R, 109V in CgPGRPS2, and 127G, 128W, 147R, 152V in CgPGRPS4), and they shared 55.9% sequence similarity. The mRNA transcripts of CgPGRPS2 and CgPGRPS4 were constitutively expressed in all the examined tissues, including haemocytes, hepatopancreas, mantle, gonad, heart, adductor muscle and gill, with the highest expression level in adductor muscle and hepatopancreas, respectively. Both CgPGRPS2 and CgPGRPS4 proteins were mainly localized in the cytoplasma. The recombinant protein of CgPGRPS2 (rCgPGRPS2) could bind lipopolysaccharide (LPS), PGN and mannan (Man), as well as various microorganisms including Gram-negative bacteria Escherichia coli, Vibrio anguillarum, Gram-positive bacteria Staphylococcus aureus and fungi Yarrowia lipolytica. The recombinant protein of CgPGRPS4 (rCgPGRPS4) exhibited higher binding affinity to PGN, lower binding affinity to LPS, while no binding activity to Man and Y. lipolytica. The results indicated that CgPGRPS2 and CgPGRPS4 could function as pattern recognition receptors (PRR) in the innate immune response of oyster, and they exhibited a certain degree of functional differentiation in recognition of Man. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Sclerochronology of Holocene oyster shells (Crassostrea gigas) from the West Coast of Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Fan, C.; Koeniger, P.; Wang, H.; Frechen, M.

    2009-04-01

    Sclerochronology, the study of periodic increments in skeletal organisms, can decipher the life history and environmental records preserved in fossil shells. Although there have been a number of studies that apply isotopic analyses to shells in open ocean and fresh water, investigations for brackish environments are rare. One of the common inhabitants in estuaries is the Crassostrea oyster. Kirby et al. (1998) demonstrated a close correspondence between the ligamental increments of convex and concave bands and yearly ^18O cycles; Andrus and Crowe (2000) found a close correspondence between translucent growth bands on the cross-section of the hinge and yearly ^18O cycles. They conclude that the morphological features on hinge and growth bands on the cross-section are formed annually and can be used to determine accurately age and growth rate in this species. However, Surge et al. (2001) could not find that these morphologic features have seasonal significance in the C. virginica shells. Therefore, these concave ridges are not reliable independent proxies of seasonality. These studies were carried out with C. virginica shells; none was studied with nature C. gigas, which was widely distributed along the Pacific coastal area. C. gigas has been introduced from its native home to all over the world, ranging from North America to Australia and Europe; it has become an important commercial harvest in many of these places. Buried Holocene oyster shells of C. gigas were sampled from a huge buried oyster reef on the West of Bohai Sea, China. One of these shells was selected for high resolution micro-sampling and stable isotope analyses testing the assumption that C. gigas ligamental increments are annual in nature. We analyzed 236 consecutive samples from the shell to show that morphologic features both on hinge and cross-section are annual by comparing them to the ^18O profiles. We tested the assumption that the morphologic features of C.gigas are delineated by convex tops

  14. Purification and characterization of a salt-tolerant cellulase from the mangrove oyster, Crassostrea rivularis.

    PubMed

    An, Tianchen; Dong, Zhu; Lv, Junchen; Liu, Yujun; Wang, Manchuriga; Wei, Shuangshuang; Song, Yanting; Zhang, Yingxia; Deng, Shiming

    2015-04-01

    A cellulase with wide range of pH resistance and high salt tolerance was isolated from the digestive gland of the oyster Crassostrea rivularis living in mangrove forests. The 27 kDa cellulase named as CrCel was purified 40.6 folds by anion exchange chromatography and extraction from the gel after non-reducing sodium dodecylsufate-polyacrylamide gel electrophoresis. The specific activity of the purified cellulase was 23.4 U/mg against carboxymethyl cellulose (CMC). The N-terminal amino acid sequence of CrCel was determined to be NQKCQANSRV. CrCel preferably hydrolyzes β-1,4-glucosidic bonds in the amorphous parts of cellulose materials and displays degradation activity toward xylan. The Km and Vmax values of CrCel for CMC were determined to be 2.1% ± 0.4% and 73.5 ± 3.3 U mg(-1), respectively. The optimal pH value and temperature of CrCel were 5.5 and 40°C, respectively. The enzyme was stable in a wide range of pH, retaining over 60% activity after incubation for 80 min in the pH range of 3.0-9.0. In addition, CrCel showed remarkable tolerance to salt and remained active at high NaCl concentrations, but also retained over 70% activity after incubation in 0.5-2 M NaCl for up to 24 h. On the basis of the N-terminal sequence alignment and its similar properties to other animal cellulases, CrCel was regarded as a member of glycosyl hydrolase family 45 β-1,4-glucanases. CrCel is the first reported cellulase isolated from mangrove invertebrates, which suggests that it may participate in the assimilation of cellulolytic materials derived from the food sources of the oyster and contribute to the consumption of mangrove primary production. The unique properties of this enzyme make it a potential candidate for further industrial application. © The Author 2015. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

  15. Interactive effects of salinity and elevated CO2 levels on juvenile eastern oysters, Crassostrea virginica.

    PubMed

    Dickinson, Gary H; Ivanina, Anna V; Matoo, Omera B; Pörtner, Hans O; Lannig, Gisela; Bock, Christian; Beniash, Elia; Sokolova, Inna M

    2012-01-01

    Rising levels of atmospheric CO(2) lead to acidification of the ocean and alter seawater carbonate chemistry, which can negatively impact calcifying organisms, including mollusks. In estuaries, exposure to elevated CO(2) levels often co-occurs with other stressors, such as reduced salinity, which enhances the acidification trend, affects ion and acid-base regulation of estuarine calcifiers and modifies their response to ocean acidification. We studied the interactive effects of salinity and partial pressure of CO(2) (P(CO2)) on biomineralization and energy homeostasis in juveniles of the eastern oyster, Crassostrea virginica, a common estuarine bivalve. Juveniles were exposed for 11 weeks to one of two environmentally relevant salinities (30 or 15 PSU) either at current atmospheric P(CO2) (∼400 μatm, normocapnia) or P(CO2) projected by moderate IPCC scenarios for the year 2100 (∼700-800 μatm, hypercapnia). Exposure of the juvenile oysters to elevated P(CO2) and/or low salinity led to a significant increase in mortality, reduction of tissue energy stores (glycogen and lipid) and negative soft tissue growth, indicating energy deficiency. Interestingly, tissue ATP levels were not affected by exposure to changing salinity and P(CO2), suggesting that juvenile oysters maintain their cellular energy status at the expense of lipid and glycogen stores. At the same time, no compensatory upregulation of carbonic anhydrase activity was found under the conditions of low salinity and high P(CO2). Metabolic profiling using magnetic resonance spectroscopy revealed altered metabolite status following low salinity exposure; specifically, acetate levels were lower in hypercapnic than in normocapnic individuals at low salinity. Combined exposure to hypercapnia and low salinity negatively affected mechanical properties of shells of the juveniles, resulting in reduced hardness and fracture resistance. Thus, our data suggest that the combined effects of elevated P(CO2) and

  16. Transformation of paralytic shellfish poisoning toxins in Crassostrea gigas and Pecten maximus reference materials.

    PubMed

    Turner, Andrew D; Lewis, Adam M; Hatfield, Robert G; Galloway, Angus W; Higman, Wendy A

    2012-11-01

    Matrix reference materials are an important requirement for the assessment of method performance characteristics and for routine quality control. In the field of marine toxin testing where biological assays have been used and where modern analytical testing methods are now becoming available, this requirement has become an urgent one. Various approaches are utilised for preparation of such materials in the absence of available naturally occurring toxic shellfish samples. Toxin-free shellfish may be artificially fortified through the addition of cultured toxic phytoplankton or shellfish may be incurred through natural feeding on toxic algae in a laboratory environment. Both of these approaches may be potentially affected by issues relating to the degradation or transformation of toxin analytes, so studies were conducted to assess these effects within our laboratory. A range of PSP-toxic shellfish tissues were prepared using the two approaches, in both Pacific oyster (Crassostrea gigas) and king scallops (Pecten maximus). Additionally, sub-samples of incurred Pacific oyster tissue were further treated, through addition of artificial chemical stabilisers and gamma irradiation. Two separate month-long stability trials were conducted at +4 °C on each material. Results highlighted clear evidence for improved stability of materials following shellfish feeding experiments in comparison with the tissues which had been spiked with plankton. In addition, there were clear differences in stability of toxins between the two shellfish species studied. There was evidence for good stability of C1&2 toxins in both the incurred tissues and improved stability of some toxins in tissues which had been subjected to either gamma irradiation or treatment with chemical additives. The results therefore highlighted the benefits of conducting shellfish feeding if suitable stable reference materials are to be prepared containing a full range of PSP toxin analytes. The study also highlighted

  17. Calcium mobilisation following shell damage in the Pacific oyster, Crassostrea gigas.

    PubMed

    Sillanpää, J K; Ramesh, K; Melzner, F; Sundh, H; Sundell, K

    2016-06-01

    Shell growth of oysters requires calcium uptake from the environment and transport to the area of shell formation. A shell regeneration assay in combination with radiolabelled calcium was used to investigate uptake and distribution of calcium to different tissues and hemolymph fractions in Pacific oysters, Crassostrea gigas (Bivalvia, Ostreoida). Oysters were notched at the shell margin and subsequently sampled for hemolymph and grading of shell regeneration during a two week experimental period. Half of the oysters were additionally exposed to (45)Ca and sampled for hemolymph and tissues. Total plasma calcium concentrations increased in notched oysters compared to controls on 1, 2 and 7days after notching. A decrease in plasma calcium levels was apparent on day 4, for both total and ionic calcium. The shell regeneration assay in the notched oysters resulted in a visible deposition of CaCO3 onto the regenerate from day 7 onwards. This was coinciding with an increased uptake of total calcium on days 11 and 14 as well as free, i.e. ionic and ligand-bound calcium, on day 14. At day 1, notching also increased calcium uptake into the mantle tissues, in areas above the notch and near the hinge. During the experiment, both the total hemocyte count and the number of granulocytes increased in notched compared to control oysters. The present study suggests that induced shell damage results in a dynamic regulation of the calcium uptake from the environment and the distribution of calcium within the body, starting directly after notching. Increases in both total calcium concentrations and uptake rates coincided with the visible depositions of CaCO3 on the regenerate shell. C. gigas was found to transport calcium mainly in the ionic form in the hemolymph, with only minor parts being bound to proteins or smaller ligands. Hemolymph measurement also revealed that C. gigas is able to regulate the extracellular concentrations of calcium and potassium. The changes in plasma calcium

  18. Transcriptomics Analysis of Crassostrea hongkongensis for the Discovery of Reproduction-Related Genes

    PubMed Central

    Tong, Ying; Zhang, Yang; Huang, Jiaomei; Xiao, Shu; Zhang, Yuehuan; Li, Jun; Chen, Jinhui; Yu, Ziniu

    2015-01-01

    Background The reproductive mechanisms of mollusk species have been interesting targets in biological research because of the diverse reproductive strategies observed in this phylum. These species have also been studied for the development of fishery technologies in molluscan aquaculture. Although the molecular mechanisms underlying the reproductive process have been well studied in animal models, the relevant information from mollusks remains limited, particularly in species of great commercial interest. Crassostrea hongkongensis is the dominant oyster species that is distributed along the coast of the South China Sea and little genomic information on this species is available. Currently, high-throughput sequencing techniques have been widely used for investigating the basis of physiological processes and facilitating the establishment of adequate genetic selection programs. Results The C.hongkongensis transcriptome included a total of 1,595,855 reads, which were generated by 454 sequencing and were assembled into 41,472 contigs using de novo methods. Contigs were clustered into 33,920 isotigs and further grouped into 22,829 isogroups. Approximately 77.6% of the isogroups were successfully annotated by the Nr database. More than 1,910 genes were identified as being related to reproduction. Some key genes involved in germline development, sex determination and differentiation were identified for the first time in C.hongkongensis (nanos, piwi, ATRX, FoxL2, β-catenin, etc.). Gene expression analysis indicated that vasa, nanos, piwi, ATRX, FoxL2, β-catenin and SRD5A1 were highly or specifically expressed in C.hongkongensis gonads. Additionally, 94,056 single nucleotide polymorphisms (SNPs) and 1,699 simple sequence repeats (SSRs) were compiled. Conclusions Our study significantly increased C.hongkongensis genomic information based on transcriptomics analysis. The group of reproduction-related genes identified in the present study constitutes a new tool for research

  19. Transcriptomics Analysis of Crassostrea hongkongensis for the Discovery of Reproduction-Related Genes.

    PubMed

    Tong, Ying; Zhang, Yang; Huang, Jiaomei; Xiao, Shu; Zhang, Yuehuan; Li, Jun; Chen, Jinhui; Yu, Ziniu

    2015-01-01

    The reproductive mechanisms of mollusk species have been interesting targets in biological research because of the diverse reproductive strategies observed in this phylum. These species have also been studied for the development of fishery technologies in molluscan aquaculture. Although the molecular mechanisms underlying the reproductive process have been well studied in animal models, the relevant information from mollusks remains limited, particularly in species of great commercial interest. Crassostrea hongkongensis is the dominant oyster species that is distributed along the coast of the South China Sea and little genomic information on this species is available. Currently, high-throughput sequencing techniques have been widely used for investigating the basis of physiological processes and facilitating the establishment of adequate genetic selection programs. The C.hongkongensis transcriptome included a total of 1,595,855 reads, which were generated by 454 sequencing and were assembled into 41,472 contigs using de novo methods. Contigs were clustered into 33,920 isotigs and further grouped into 22,829 isogroups. Approximately 77.6% of the isogroups were successfully annotated by the Nr database. More than 1,910 genes were identified as being related to reproduction. Some key genes involved in germline development, sex determination and differentiation were identified for the first time in C.hongkongensis (nanos, piwi, ATRX, FoxL2, β-catenin, etc.). Gene expression analysis indicated that vasa, nanos, piwi, ATRX, FoxL2, β-catenin and SRD5A1 were highly or specifically expressed in C.hongkongensis gonads. Additionally, 94,056 single nucleotide polymorphisms (SNPs) and 1,699 simple sequence repeats (SSRs) were compiled. Our study significantly increased C.hongkongensis genomic information based on transcriptomics analysis. The group of reproduction-related genes identified in the present study constitutes a new tool for research on bivalve reproduction

  20. Transcriptional changes in oysters Crassostrea brasiliana exposed to phenanthrene at different salinities.

    PubMed

    Zacchi, Flávia Lucena; de Lima, Daína; Flores-Nunes, Fabrício; Mattos, Jacó Joaquim; Lüchmann, Karim Hahn; de Miranda Gomes, Carlos Henrique Araújo; Bícego, Márcia Caruso; Taniguchi, Satie; Sasaki, Silvio Tarou; Dias Bainy, Afonso Celso

    2017-02-01

    Euryhaline animals from estuaries, such as the oyster Crassostrea brasiliana, show physiological mechanisms of adaptation to tolerate salinity changes. These ecosystems receive constant input of xenobiotics from urban areas, including polycyclic aromatic hydrocarbons (PAHs), such as phenanthrene (PHE). In order to understand the influence of salinity on the molecular responses of C. brasiliana exposed to PHE, oysters were acclimatized to different salinities (35, 25 and 10) for 15days and then exposed to 100μgL(-1) PHE for 24h and 96h. Control groups were kept at the same salinities without PHE. Oysters were sampled for chemical analysis and the gills were excised for mRNA quantification by qPCR. Transcript levels of different genes were measured, including some involved in oxidative stress pathways, phases I and II of the xenobiotic biotransformation systems, amino acid metabolism, fatty acid metabolism and aryl hydrocarbon receptor nuclear translocator putative gene. Higher transcript levels of Sulfotransferase-like gene (SULT-like) were observed in oysters exposed to PHE at salinity 10 compared to control (24h and 96h); cytochrome P450 isoforms (CYP2AU1, CYP2-like1) were more elevated in oysters exposed for 24h and CYP2-like2 after 96h of oysters exposed to PHE at salinity 10 compared to control. These results are probably associated to an enhanced Phase I biotransformation activity required for PHE detoxification under hyposmotic stress. Higher transcript levels of CAT-like, SOD-like, GSTm-like (96h) and GSTΩ-like (24h) in oysters kept at salinity 10 compared to organisms at salinities 25 and/or 35 are possibly related to enhaced ROS production. The transcription of these genes were not affected by PHE exposure. Amino acid metabolism-related genes (GAD-like (24h), GLYT-like, ARG-like (96h) and TAUT-like at 24h and 96h) also showed different transcription levels among organisms exposed to different salinities, suggesting their important role for oyster

  1. Comparative chlorine and temperature tolerance of the oyster Crassostrea madrasensis: implications for cooling system fouling.

    PubMed

    Rajagopal, S; Venugopalan, V P; van der Velde, G; Jenner, H A

    2003-04-01

    Crassostrea madrasensis is an important fouling oyster in tropical industrial cooling water systems. C. madrasensis individuals attach to surfaces by cementing one of their two valves to the substratum. Therefore, oyster fouling creates more problems than mussel fouling in the cooling conduits of power stations, because unlike the latter, the shell of the former remains attached to the substratum even after the death of the animal. However, there are no published reports on the tolerance of this species to chlorination and heat treatment. The mortality pattern and physiological behaviour (oxygen consumption and filtration rate) of three size groups (13 mm, 44 mm and 64 mm mean shell length) of C. madrasensis were studied at different residual chlorine concentrations (0.25, 0.5, 0.75, 1, 2, 3 to 5 mg 1-1) and temperatures (30 degrees C to 45 degrees C). The effect of shell size (= age) on C. madrasensis mortality in the presence of chlorine and taking into account temperature was significant, with the largest size group oysters showing highest resistance. At 1 mg l-1 residual chlorine, the 13 mm and 64 mm size group oysters, took 504 h (21 d) and 744 h (31 d), respectively to reach 100% mortality. At 39 degrees C, the 13 mm size group oysters took 218 min to reach 100% mortality, whereas the 64 mm size group oysters took 325 min. The oxygen consumption and filtration rate of C. madrasensis showed progressive reduction with increasing residual chlorine concentrations. However, the filtration rate and oxygen consumption responses of C. madrasensis were not significantly different between 30 degrees C (control) and 37.5 degrees C. There was a sharp decrease in the filtration rate and oxygen consumption at 38.5 degrees C. A comparison of the present mortality data with previous reports on other bivalves suggests that the chlorine tolerance of C. madrasensis lies in between that of Perna viridis and Perna perna, while its temperature tolerance is significantly higher

  2. Unusually abundant and large ciliate xenomas in oysters, Crassostrea virginica, from Great Bay, New Hampshire, USA.

    PubMed

    McGurk, Emily Scarpa; Ford, Susan; Bushek, David

    2016-06-01

    During routine histological examination of oysters (Crassostrea virginica) from Great Bay, New Hampshire, USA, a high prevalence and intensity of ciliate xenomas has been noted since sampling began in 1997. Xenomas are hypertrophic lesions on the gills of bivalve molluscs caused by intracellular ciliates, likely Sphenophrya sp. Although not known to cause mortality in oysters, xenomas have not previously been reported at this high abundance. The objectives of this study were to characterize the xenomas, describe the ciliates, and gather baseline epizootiological data with correlations to environmental and biological parameters. Upon gross examination, xenomas appeared as white nodules, up to 3mm in diameter, located in the gill tissue and occasionally fusing into large masses along the gill filaments. Light microscopy of histological sections revealed xenomas located in the gill water tubes, which they often completely blocked. Higher magnification revealed dual nuclei, eight kineties, and conjugation of the ciliates. Transmission electron microscopy revealed dual nuclei that varied in density, a maximum of twenty cilia in each kinety radiating from the oral apparatus to the posterior, and a 9+2 axoneme structure within the cilia. These traits place the ciliates into the Order Rhynchodida, but insufficient molecular data exist to confirm classification of this ciliate to the Genus Sphenophrya. Since 1997, xenoma prevalence has fluctuated with peaks in 2000, 2004, and 2011. Infected oysters generally contained <30 xenomas, but 2.1% contained >100, sharply contrasting the rare prevalence and low intensity reported elsewhere. Prevalence increased with oyster size, leveling off near 50% in oysters >60mm. Infection intensity peaked in 70-90mm oysters and declined in larger oysters. Individual oyster condition was not associated with xenoma intensity, but sites with oysters in higher condition generally had a greater prevalence and intensity of xenoma infections

  3. Identification of Dopamine D2 Receptors in Gill of Crassostrea virginica

    PubMed Central

    Anador, Samuel; Brown, Cherryle; Adebesin, Damilola; Cilli, Noelia; Fleming, Renee; Carroll, Margaret A.; Catapane, Edward J.

    2011-01-01

    The lateral epithelial cells of gill of Crassostrea virginica are innervated by dopamine and serotonin nerves that regulate the beating rate of their lateral cilia. Terminal release of dopamine slows down the beating rate of the cilia, while serotonin release increases the beating rate. Previously, we showed that the dopaminergic, but not the serotonergic, mechanism regulating the beating rate of the lateral cilia was disrupted by manganese treatments and that this disruption was occurring postsynaptically, at the level of the dopamine receptor or further downstream in the signal transduction pathway. In humans manganese toxicity causes Manganism, a neurological disorder with clinical symptoms similar to Parkinson s disease. In this study we utilized pharmacological agents and an immunohistofluorescence technique to characterize the dopamine receptor type present on the lateral ciliated cells of C. virginica gill. Agonists and antagonists to dopamine D1 or dopamine D2 receptors were applied to gill sections and beating rates of the lateral cilia were measured by stroboscopic microscopy. The D2 agonists and D2 antagonists were effective in mimicking or blocking, respectively, the inhibitory actions of dopamine on lateral cilia beating, while application of either D1 agonists or D1 antagonists had no significant effect. In other experiments we used an epilume fluorescence microscopic fitted with FITC filters to view gill sections treated with a primary antibody against D2 receptors and a FITC-linked secondary antibody. Control gill sections without primary antibody exposure were similarly treated and viewed. The D2 antibody treated sections showed bright fluorescent receptor-antibody complexes present at the lateral ciliated cells and other areas of gill, when compared to controls. The results of our immunofluorescence study identify the presence of D2-like receptors on the lateral ciliated cells of C. virginica gill and our pharmacological results indicate that D2

  4. Effects of natural oyster reefs (Crassostrea gigas) on the sediment balance of Oosterschelde tidal flats

    NASA Astrophysics Data System (ADS)

    Paiva, João; de Vries, Mindert

    2014-05-01

    The realization of the storm surge barrier and the two secondary dams not only changed the hydrodynamics, but also the geomorphological characteristics of the Oosterschelde estuary (SW Netherlands) creating a disequilibrium between erosion and sedimentation. This has lead in the last 25 years to a sand deficit in the Oosterschelde resulting in the erosion of the tidal flats (Smaal & Nienhuis, 1992; Nienhuis & Smaal 1994). Due to these phenomena the habitat for intertidal soft-bottom benthic fauna is slowly disappearing, and with it food sources for estuarine birds that use these areas as foraging grounds (Mulder & Louters, 1994). Erosion of tidal flats also locally exposes deeper peat layers, potentially resulting in reduced water clarity and primary production (Nienhuis & Smaal 1994). Adding to these problems an increased risk of dike failures and flooding during storm surges is expected, as the dikes gradually become more exposed to wave action. In this research the effect of oysters (Crassostrea gigas) as ecosystem engineers, on the sediment balance in the Oosterschelde was studied. In our analysis we compared long term bathymetry data for transects with and without oyster reefs. Based on height differences, the transects sedimentation/erosion rates were calculated and used to determine if there was a difference between transects without oyster reefs and transects crossing oyster reefs. From the long term analysis, the overall erosional trend of the Oosterschelde tidal flats is clear. The mean observed erosion was - 0,012 m per year. When considering the sections crossing oyster reefs , a mean accumulation of sediment of + 0,007 m per year was observed. The results suggest that these ecosystem engineers, that cover large areas in the Oosterschelde slow down the erosion of the tidal flats in the Oosterschelde, as they act as sediment accumulators and stabilizers. We estimate at least 70000 m3 of sediment per year is accreted on tidal flats due to the effect of

  5. Improving management support tools for reintroducing bivalve species (eastern oyster [Crassostrea virginica Gmelin]) in urban estuaries.

    PubMed

    Ravit, Beth; Cooper, Keith; Buckley, Brian; Comi, Meredith; McCandlish, Elizabeth

    2014-10-01

    Successful reintroduction of "ecologically extinct" bivalve species into anthropogenically impaired urban estuaries is problematic when employing existing management tools used in estuaries where bivalves are present (GIS-based restoration models, expanding existing shellfish beds, placement of shell substrate, physical oceanographic parameters). A significant management challenge is appropriate site selection. We are proposing the inclusion of a biological parameter (evaluation of tissue histopathology) in an inexpensive and rapid site selection model to inform management decision making and identify sites with the greatest potential for reintroduction success. Use of biological biomarkers is not a new concept, but it is important that they be included in a multitiered management approach to bivalve reintroduction. This Case Study tested adult Eastern Oysters (Crassostrea virginica Gmelin) from locations that supported comparable short-term survival rates by evaluating growth and tissue health and/or disease. Biomarkers indicated oyster tissues at one site were normal, the female:male sex ratio was 50:50, and female oysters were in spawning condition. Conversely, oyster tissues at the second site exhibited multiple abnormalities, samples were 100% male, and the incidence of disease was high. Using the biomarker tool, we evaluated 4 additional sites where oysters exhibited short-term (1 year) survival. At 2 locations, we observed chronic health impacts that would preclude reintroduction, including samples from one site where a wild population was surviving. We also analyzed tissue and shell heavy metal contents. Soft tissue metal concentrations in Meadowlands samples were at the high range of scientific literature values, averaging 1.1% of total body weight, whereas tissue metal concentrations at the Keyport site were within acceptable ranges. Although initial survival and growth rates at both locations were comparable, site-specific urban stressors reduced oyster

  6. Mangroves and shoreline change on Molokai, Hawaii: Assessing the role of introduced Rhizophora mangle in sediment dynamics and coastal change using remote sensing and GIS

    NASA Astrophysics Data System (ADS)

    D'Iorio, Margaret Mary

    The Florida red mangrove, Rhizophora mangle, was introduced to the high volcanic island of Molokai, Hawaii in 1902 to trap sediment and stabilize eroding coastal mudflats along the island's reef-fringed south coast. This prolific invasive species now occupies 2.4 km2 of inter-tidal land and borders approximately 20% of the south coast shoreline. Integrating the fundamentals of remote sensing and Geographical Information Systems, this research investigates the effects of mangrove introduction on sediment dynamics and coastal change on south Molokai throughout the 20th century and provides a baseline of mangrove distribution, a detailed record of shoreline change rates, and a chronological history of island land use and environmental change. Monitoring of coastal change associated with mangroves is essential to understanding how natural coastal ecosystems react to alien species introductions and adapt overall to changing climatic regimes. Comparing the accuracy of various remote sensing instruments and processing techniques, this study has shown that the remote sensing with modern airborne and satellite sensors offers an effective management tool for mapping baseline conditions and monitoring change in remote island environments like that on the south coast of Molokai. Shoreline change assessment found that shoreline change rates on the island's south coast varied both alongshore and through time and that the dominant change has been one of progradation. Rates of change peaked in the early part of the 20th century and have since decayed exponentially over time. Changing land use practices coupled with the introduction of invasive species may have strongly influenced observed variability in rates of coastal change. Field observations and sediment analysis suggest that sediment transfer across the coastal boundary on the mangrove-fringed south coast is relatively limited and appears to be mainly event-driven. For shallow, reef-fringed, coastal regions vulnerable to

  7. δ 15N Studies of Nitrogen Use by the Red Mangrove, Rhizophora mangle L. in South Florida

    NASA Astrophysics Data System (ADS)

    Fry, B.; Bern, A. L.; Ross, M. S.; Meeder, J. F.

    2000-02-01

    To help define nitrogen (N) sources and patterns of N processing in mangrove ecosystems, mangrove leaf nitrogen contents and δ 15N values were assayed in three marshes along the south Florida coast. In each marsh, leaf samples were collected from dwarf mangroves at interior locations and taller mangroves at the ocean fringe. Leaf % N and δ 15N values did not differ consistently between dwarf and tall mangroves, even though there were large variations in δ 15N (18‰ range, -5 to +13‰) and % N (1·2% range, 0·9-2·1%). Highest % N and δ 15N values occurred along the western margin of Biscayne Bay where canals draining agricultural lands deliver high-nitrate waters to fringing mangrove marshes. High mangrove δ 15N values may be good biomonitors of anthropogenic N loading to south Florida estuaries. Lower values likely reflect less anthropogenic N entering the mangrove marshes, as well as differences in plant physiology that occur along the fringe-dwarf gradient.

  8. Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

    PubMed

    Wang, Rui Xuan; Wang, AnLi; Wang, Jiang Yong

    2014-11-01

    A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar.

  9. A review of current state of knowledge concerning Perkinsus marinus effects on Crassostrea virginica (Gmelin) (the eastern oyster).

    PubMed

    Smolowitz, R

    2013-05-01

    The eastern oyster, Crassostrea virginica (Gmelin), is both an important component of our estuaries and an important farmed food animal along the east and south coasts of the United States. Its populations have been significantly diminished in the wild due to decades of overfishing beginning in the 1890 s. Unfortunately, in 1950, a new disease in eastern oysters caused by the protistan agent, Perkinsus marinus, was identified. The disease, resulting from infection with this protozoan, leads to high mortality of both wild and cultured eastern oysters. Current restoration efforts are hampered by the disease, as is the aquaculture of this economically important food. The parasite infects hemocytes and causes hemolytic anemia and general degeneration of the tissues, leading to death. Ongoing research efforts are attempting to develop oysters resistant to the disease. Transport regulations exist in may states. Infection with P. marinus is listed as a reportable disease by the World Health Organization.