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Sample records for fortunei bivalvia mytilidae

  1. Physiological response of invasive mussel Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae) submitted to transport and experimental conditions.

    PubMed

    Cordeiro, N I S; Andrade, J T M; Montresor, L C; Luz, D M R; Araújo, J M; Martinez, C B; Pinheiro, J; Vidigal, T H D A

    2017-03-01

    Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally

  2. Sequence motifs associated with paternal transmission of mitochondrial DNA in the horse mussel, Modiolus modiolus (Bivalvia: Mytilidae).

    PubMed

    Robicheau, Brent M; Breton, Sophie; Stewart, Donald T

    2017-03-20

    In the majority of metazoans paternal mitochondria represent evolutionary dead-ends. In many bivalves, however, this paradigm does not hold true; both maternal and paternal mitochondria are inherited. Herein, we characterize maternal and paternal mitochondrial control regions of the horse mussel, Modiolus modiolus (Bivalvia: Mytilidae). The maternal control region is 808bp long, while the paternal control region is longer at 2.3kb. We hypothesize that the size difference is due to a combination of repeated duplications within the control region of the paternal mtDNA genome, as well as an evolutionarily ancient recombination event between two sex-associated mtDNA genomes that led to the insertion of a second control region sequence in the genome that is now transmitted via males. In a comparison to other mytilid male control regions, we identified two evolutionarily Conserved Motifs, CMA and CMB, associated with paternal transmission of mitochondrial DNA. CMA is characterized by a conserved purine/pyrimidine pattern, while CMB exhibits a specific 13bp nucleotide string within a stem and loop structure. The identification of motifs CMA and CMB in M. modiolus extends our understanding of Sperm Transmission Elements (STEs) that have recently been identified as being associated with the paternal transmission of mitochondria in marine bivalves.

  3. A Methanotrophic Marine Molluscan (Bivalvia, Mytilidae) Symbiosis: Mussels Fueled by Gas

    NASA Astrophysics Data System (ADS)

    Childress, James J.; Fisher, C. R.; Brooks, J. M.; Kennicutt, M. C.; Bidigare, R.; Anderson, A. E.

    1986-09-01

    An undescribed mussel (family Mytilidae), which lives in the vicinity of hydrocarbon seeps in the Gulf of Mexico, consumes methane (the principal component of natural gas) at a high rate. The methane consumption is limited to the gills of these animals and is apparently due to the abundant intracellular bacteria found there. This demonstrates a methane-based symbiosis between an animal and intracellular bacteria. Methane consumption is dependent on the availability of oxygen and is inhibited by acetylene. The consumption of methane by these mussels is associated with a dramatic increase in oxygen consumption and carbon dioxide production. As the methane consumption of the bivalve can exceed its carbon dioxide production, the symbiosis may be able to entirely satisfy its carbon needs from methane uptake. The very light (δ 13C = -51 to -57 per mil) stable carbon isotope ratios found in this animal support methane (δ 13C = -45 per mil at this site) as the primary carbon source for both the mussels and their symbionts.

  4. A new species of pea crab of the genus Serenotheres Ahyong & Ng, 2005 (Crustacea, Brachyura, Pinnotheridae) from the date mussel Leiosolenus Carpenter, 1857 (Mollusca, Bivalvia, Mytilidae, Lithophaginae) from the Solomon Islands.

    PubMed

    Ng, Peter K L; Meyer, Chistopher

    2016-01-01

    The pea crab genus Serenotheres Ahyong & Ng, 2005 (Pinnotheridae) is currently only represented by one species, Serenotheres besutensis (Serène, 1967). A new species is now assigned to this genus, described from a date mussel Leiosolenus obesus Carpenter, 1857 (Mollusca: Bivalvia: Mytilidae: Lithophaginae) collected in the Solomon Islands. Serenotheres janussp. n. differs from Serenotheres besutensis in possessing a conspicuously broader carapace, with the lateral margins of the dorsal lamellum distinctly produced and the posterolateral part deeply concave, the dorsal lamellum being highest at the median cleft, the rostrum is relatively more prominent, the surfaces of the anterolateral margin and hepatic region are less prominently pitted and eroded, the ischiomerus of the third maxilliped is relatively more rectangular, and the P2 merus is proportionately longer.

  5. A new species of pea crab of the genus Serenotheres Ahyong & Ng, 2005 (Crustacea, Brachyura, Pinnotheridae) from the date mussel Leiosolenus Carpenter, 1857 (Mollusca, Bivalvia, Mytilidae, Lithophaginae) from the Solomon Islands

    PubMed Central

    Ng, Peter K. L.; Meyer, Chistopher

    2016-01-01

    Abstract The pea crab genus Serenotheres Ahyong & Ng, 2005 (Pinnotheridae) is currently only represented by one species, Serenotheres besutensis (Serène, 1967). A new species is now assigned to this genus, described from a date mussel Leiosolenus obesus Carpenter, 1857 (Mollusca: Bivalvia: Mytilidae: Lithophaginae) collected in the Solomon Islands. Serenotheres janus sp. n. differs from Serenotheres besutensis in possessing a conspicuously broader carapace, with the lateral margins of the dorsal lamellum distinctly produced and the posterolateral part deeply concave, the dorsal lamellum being highest at the median cleft, the rostrum is relatively more prominent, the surfaces of the anterolateral margin and hepatic region are less prominently pitted and eroded, the ischiomerus of the third maxilliped is relatively more rectangular, and the P2 merus is proportionately longer. PMID:27843386

  6. Karyotypic diversification in Mytilus mussels (Bivalvia: Mytilidae) inferred from chromosomal mapping of rRNA and histone gene clusters

    PubMed Central

    2014-01-01

    Background Mussels of the genus Mytilus present morphologically similar karyotypes that are presumably conserved. The absence of chromosome painting probes in bivalves makes difficult verifying this hypothesis. In this context, we comparatively mapped ribosomal RNA and histone gene families on the chromosomes of Mytilus edulis, M. galloprovincialis, M. trossulus and M. californianus by fluorescent in situ hybridization (FISH). Results Major rRNA, core and linker histone gene clusters mapped to different chromosome pairs in the four taxa. In contrast, minor rRNA gene clusters showed a different behavior. In all Mytilus two of the 5S rDNA clusters mapped to the same chromosome pair and one of them showed overlapping signals with those corresponding to one of the histone H1 gene clusters. The overlapping signals on mitotic chromosomes became a pattern of alternate 5S rRNA and linker histone gene signals on extended chromatin fibers. Additionally, M. trossulus showed minor and major rDNA clusters on the same chromosome pair. Conclusion The results obtained suggest that at least some of the chromosomes bearing these sequences are orthologous and that chromosomal mapping of rRNA and histone gene clusters could be a good tool to help deciphering some of the many unsolved questions in the systematic classification of Mytilidae. PMID:25023072

  7. Mitochondrial genomes and Doubly Uniparental Inheritance: new insights from Musculista senhousia sex-linked mitochondrial DNAs (Bivalvia Mytilidae)

    PubMed Central

    2011-01-01

    Background Doubly Uniparental Inheritance (DUI) is a fascinating exception to matrilinear inheritance of mitochondrial DNA (mtDNA). Species with DUI are characterized by two distinct mtDNAs that are inherited either through females (F-mtDNA) or through males (M-mtDNA). DUI sex-linked mitochondrial genomes share several unusual features, such as additional protein coding genes and unusual gene duplications/structures, which have been related to the functionality of DUI. Recently, new evidence for DUI was found in the mytilid bivalve Musculista senhousia. This paper describes the complete sex-linked mitochondrial genomes of this species. Results Our analysis highlights that both M and F mtDNAs share roughly the same gene content and order, but with some remarkable differences. The Musculista sex-linked mtDNAs have differently organized putative control regions (CR), which include repeats and palindromic motifs, thought to provide sites for DNA-binding proteins involved in the transcriptional machinery. Moreover, in male mtDNA, two cox2 genes were found, one (M-cox2b) 123bp longer. Conclusions The complete mtDNA genome characterization of DUI bivalves is the first step to unravel the complex genetic signals allowing Doubly Uniparental Inheritance, and the evolutionary implications of such an unusual transmission route in mitochondrial genome evolution in Bivalvia. The observed redundancy of the palindromic motifs in Musculista M-mtDNA may have a role on the process by which sperm mtDNA becomes dominant or exclusive of the male germline of DUI species. Moreover, the duplicated M-COX2b gene may have a different, still unknown, function related to DUI, in accordance to what has been already proposed for other DUI species in which a similar cox2 extension has been hypothesized to be a tag for male mitochondria. PMID:21896183

  8. Sulphur-oxidizing extracellular bacteria in the gills of Mytilidae associated with wood falls.

    PubMed

    Duperron, Sébastien; Laurent, Mélina C Z; Gaill, Françoise; Gros, Olivier

    2008-03-01

    Six morphotypes of small mussels (Bivalvia: Mytilidae) were found attached to naturally sunken wood collected in the Bohol Sea (Philippines). These specimens are related to the large Bathymodiolus mussels that are found worldwide at cold seeps and hydrothermal vents. In these habitats, the mytilids harbour sulphur- and methane-oxidizing endosymbionts in their gills and depend on the energy and carbon provided by the symbionts. In this study, bacteria associated with the gills of wood-associated mussels are characterized using molecular and microscopic techniques. The existence of bacteria in the lateral zone of gill filaments in all specimens is demonstrated. Comparative analyses of 16S rRNA gene and adenosine 5'-phosphosulphate (APS) reductase gene sequences indicate that the bacteria are closely related to sulphur-oxidizing endosymbionts of Bathymodiolus. FISHs using specific probes confirm that sulphur oxidizers are by far the most abundant, if not the only bacteria present. Electron micrographs displayed mostly extracellular bacteria located between microvilli at the apical surface of host gill epithelial cells all along the lateral zone of each gill filament. In some specimens, occasional occurrence of intracellular bacteria with similar morphology was noted. This study provides the first molecular evidence for the presence of possible thiotrophic symbiosis in sunken wood ecosystems. With their epibiotic bacteria, wood-associated mussels display a less integrated type of interaction than described in their seep, vent and whale fall relatives.

  9. Pollution monitoring in Southeast Asia using biomarkers in the mytilid mussel Perna viridis (Mytilidae: Bivalvia).

    PubMed

    Nicholson, S; Lam, P K S

    2005-01-01

    Mytilid mussels have been extensively used in marine pollution monitoring programmes in temperate regions of the world although widespread subtropical representatives such as Perna viridis have only comparatively recently been utilised to monitor the sublethal effects of pollution in Southeast Asia. P. viridis is considered a subtropical equivalent of the temperate Mytilus sp. and has considerable potential for pollution monitoring throughout its geographical range. This paper reviews the current status of biomarkers in P. viridis and provides some recommendations on biological-effects monitoring to facilitate the assessment of coastal pollution in Southeast Asia.

  10. Hypoxia effects on oxidative stress and immunocompetence biomarkers in the mussel Perna perna (Mytilidae, Bivalvia).

    PubMed

    Nogueira, Lílian; Mello, Danielle Ferraz; Trevisan, Rafael; Garcia, Danielly; da Silva Acosta, Daiane; Dafre, Alcir Luiz; de Almeida, Eduardo Alves

    2017-05-01

    This study investigated the effects of hypoxia on oxidative stress response and immune function in mussels Perna perna exposed to air for 6, 12, 24 and 48 h. In air-exposed mussels, the antioxidant enzymes superoxide dismutase (SOD), catalase, and glutathione reductase (GR) activities were lower in gill tissues (24-48 h) and digestive gland (12 h), while the glutathione peroxidase and GR activities were increased in the digestive gland (48 h). In both tissues, aerial exposure promoted a rapid (6 h) and persistent (up to 48 h) increase of glutathione levels. Decreased hemocyte count and viability, as well as increased phagocytic activity and cellular adhesion capacity were detected after prolonged aerial exposure (>12 h). In summary, induction of thiol pools, altered antioxidant enzyme activities, and activation of immune responses were detected in hypoxia exposed brown mussels, indicating hypoxia induced tissue-specific responses in both antioxidant and immune systems.

  11. Complete mitochondrial genome of the Asian green mussel Perna viridis (Bivalvia, Mytilidae).

    PubMed

    Li, Xiaoling; Wu, Xiangyun; Yu, Ziniu

    2012-10-01

    The complete mitochondrial (mt) genome of the Asian green mussel Perna viridis (16,627 bp), an economically important bivalve, was newly sequenced and annotated. P. viridis is the shortest and has a comparatively highest overall A+T content (68%) among six available genomes of marine mussels to date. The atp8 gene's length (49 a.a.) of the green mussel is unexpectedly greatly shorter than that of other marine mussels (87 a.a.). Comparison of the gene order demonstrated that the six marine mussels share no identical gene blocks although they belong to the same family, which indicates that this group should be a good model to study mtDNA evolution and mitochondria inheritance.

  12. Cytogenetic characterization of the invasive mussel species Xenostrobus securis Lmk. (Bivalvia: Mytilidae).

    PubMed

    Pérez-García, Concepción; Morán, Paloma; Pasantes, Juan J

    2011-09-01

    The chromosomes of the invasive black-pigmy mussel (Xenostrobus securis (Lmk. 1819)) were analyzed by means of 4',6-diamidino-2-phenylindole (DAPI) / propidium iodide (PI) and chromomycin A3 (CMA) / DAPI fluorescence staining and fluorescent in situ hybridization using major rDNA, 5S rDNA, core histone genes, linker histone genes, and telomeric sequences as probes. The diploid chromosome number in this species is 2n = 30. The karyotype is composed of seven metacentric, one meta/submetacentric, and seven submetacentric chromosome pairs. Telomeric sequences appear at both ends of every single chromosome. Major rDNA clusters appear near the centromeres on chromosome pairs 1 and 3 and are associated with bright CMA fluorescence and dull DAPI fluorescence. This species shows five 5S rDNA clusters close to the centromeres on four chromosome pairs (2, 5, 6, and 8). Three of the four core histone gene clusters map to centromeric positions on chromosome pairs 7, 10, and 13. The fourth core histone gene cluster occupies a terminal position on chromosome pair 8, also bearing a 5S rDNA cluster. The two linker histone gene clusters are close to the centromeres on chromosome pairs 12 and 14. Therefore, the use of these probes allows the unequivocal identification of 11 of the 15 chromosome pairs that compose the karyotype of X. securis.

  13. Parasites of the mangrove mussel Mytella guyanensis (Bivalvia: Mytilidae) in Camamu Bay, Bahia, Brazil.

    PubMed

    Ceuta, L O; Boehs, G

    2012-08-01

    This contribution reports the parasites found in the mangrove mussel Mytella guyanensis in Camamu Bay, Bahia, Brazil. Samples were collected monthly from September 2006 through October 2007. A total of 460 individuals were collected, fixed in Davidson's solution, and processed by standard histological techniques, and the sections were stained with Harris hematoxylin and eosin (H&E). The water temperature ranged from 23.5 to 31.6 ºC, and the salinity from 25 to 37‰. Microscopic analysis showed Rickettsia-like organisms (RLOs), Nematopsis sp. (Apicomplexa), and Platyhelminthes, including a turbellarian, sporocysts of Bucephalus sp., metacercariae, and metacestodes of Tylocephalum sp. Parasites were observed mainly in the gills, mantle, and digestive gland. The prevalence of Nematopsis sp. was 100%, and in heavily infected mussels the tissues of the labial palps were damaged. RLOs occurred in high prevalence and intensity of infection in some periods. The digenean sporocysts showed moderate prevalence but high intensity of infection, and caused parasitic castration. In general, there was no significant spatial or temporal variation (p > 0.05) of the parasites, which is probably attributable to the small variations of temperature and salinity in the region.

  14. Gill Development and its functional and evolutionary implications in the blue mussel Mytilus edulis (Bivalvia: Mytilidae).

    PubMed

    Cannuel, Rozenn; Beninger, Peter G; McCombie, Helen; Boudry, Pierre

    2009-10-01

    Study of gill development in bivalve larvae and postlarvae provides information on the evolution of this organ and feeding mechanisms of early stages. Scanning electron microscopy was used to document the development of the filibranch homorhabdic gill in hatchery-reared larval, postlarval, and juvenile Mytilus edulis. Four key stages were identified during gill development: (1) transfer of the particle collection function from velum to gill at metamorphosis, with subsequent elongation of the gill filaments to form a gill basket, with complete frontal ciliation; (2) reflection of the inner demibranchs, and transition to a V-shaped gill; (3) delayed development of the outer demibranchs, occuring simultaneously along the gill axis, with transition to the adult final W-shape; and (4) formation of the ventral particle grooves and concomitant acquisition of dense abfrontal ciliation. These key stages signal shifts in the mechanisms of particle processing during the early development of M. edulis. Gill development in the homorhabdic filibranch M. edulis was similar to that of the early homorhabdic stages of the heterorhabdic filibranchs studied to date (Pectinidae), but different from that of the pseudolamellibranchs (Ostreidae), suggesting divergent evolution of this character. Similarly, the systems responsible for gill cohesion and structural integrity are common to both the homorhabdic and heterorhabdic filibranchs, suggesting evolutionary proximity, but they are patently different from those of the eulamellibranchs and pseudolamellibranchs, suggesting evolutionary divergence.

  15. Influence of salinity on the physiological conditions in mussels, Perna perna and Perna viridis (Bivalvia: Mytilidae).

    PubMed

    Segnini de Bravo, Mary Isabel

    2003-06-01

    Perna genus was introduced to Venezuela, but nowadays, Perna perna and Perna viridis coexist and are commercially exploited from their natural beds. The aim of this work was to determine the effect of salinity on the physiological conditions of these species by studying RNA/DNA and Protein/DNA ratios. The organisms were collected from natural beds at La Esmeralda, Sucre State, Venezuela, and acclimatized for 15 days under laboratory conditions at 25 degrees C, 36 per thousand salinity, pH between 7 and 8 and more than 90% of oxygen saturation. Later, they were divided in two groups: for one group, the salinity concentration was increased (36 to 45 per thousand), and for the other, the salinity was decreased (36 to 15 per thousand). The rate of change was 1 per thousand every day. Ten organisms per group of both species were taken at each of 15, 20, 25, 30, 36, 40 y 45 per thousand salinity concentrations. Protein (colorimetric method) and nucleic acids (RNA and DNA by fluorometric method) concentrations were measured in the digestive gland, gills and adductor muscle tissues. Results indicate that P. perna can physiologically compensate the increase in salinity, but not when the salinity decreased, when proteins are the most needed macromolecules. The Protein/DNA index is directly related to salinity changes in both cases. P. viridis shows physiological compensation to salinity increases and decreases. The RNA/DNA index value in both cases supports this. Digestive gland and muscle tissues are the regulating tissues in both species. These results show that P. viridis has a higher degree of adaptability to salinity changes and, therefore, a greater potential for aquaculture than P. perna.

  16. [Histomorphological study on folk medicine Lysimachia fortunei].

    PubMed

    Wu, Zhi-gui; Fu, Xiao-mei; Hu, Sheng-fu; Pei, Jian-guo; Ge, Fei; Chu, Xiao-lan; Fan, Cui-sheng

    2015-02-01

    To set standards for histomorphological studies on Lysimachia fortunei, an efficacious and widely applied folk medicine in this study, in order to develop its resources. Its species were identified by observing plant morphology and herbs appearance characters, preparing slices with routine methods and defining structural characters. According to the results of morphologic observation, leaves, stamen and pistil of this plant were different from the descriptions in Flora of China. The whole herb can be used in medicines, mainly including rhizomes, stems and leaves. According to the findings in the first study on microscopic structures, its rhizomes, stems and leaves were characteristic and worth identifying. The transaction tissue structures of rhizomes and stems were under developed and contained endodermis, secretory structures; Stems had sclerenchymata of different shapes of sclereids; Leaves were bifacial and had vascular bundles under midribs, which were surrounded by parenchymal sheathes. On the surface of leaves, stomata, glandular hairs and keratin lines were morphologically different in upper and lower epidermis. The herbal power had glandular hairs, sclereids and vessels. In conclusion, herbs of L. fortunei can be identified by the above histomorphological characteristics, which lays a foundation for further development and application of L. fortunei.

  17. Colwellia and sulfur-oxidizing bacteria: An unusual dual symbiosis in a Terua mussel (Mytilidae: Bathymodiolinae) from whale falls in the Antilles arc

    NASA Astrophysics Data System (ADS)

    Duperron, Sébastien; Gros, Olivier

    2016-09-01

    Seven individuals of a single morphotype of mussels (Bivalvia: Mytilidae) were found attached to a naturally sunken whale intervertebral disk collected in Guadeloupe (Caribbean) at 800 m depth. These specimens resemble small Idas mussels which are found worldwide at cold seeps and hydrothermal vents, and typically harbor ectosymbiotic bacteria on their gills upon which they depend for nutrition. Based on multi-locus gene sequencing, these specimens appear to belong to a new species closely related to two species now included within the genus Terua. Unexpectedly, its closest relatives are found in the Pacific, questioning how this species has reached the Antilles arc. Based on marker gene sequence analysis, electron and fluorescence microscopy, Terua n. sp. harbors two distinct and abundant extracellular bacterial symbionts located between microvilli at the apical surface of host gill epithelial cells. One is a sulfur-oxidizing bacterium similar to the symbionts previously identified in several deep-sea mussels, while the other is related to Colwellia species, a group of cold-adapted heterotrophic bacteria able to degrade organic compounds. This study provides the first evidence for the existence of a dual symbiosis in mussels from whale fall ecosystems in the Caribbean. The evolutionary history of Terua n. sp. and potential role of its Colwellia symbionts are discussed.

  18. Differential Transcriptome Analysis between Paulownia fortunei and Its Synthesized Autopolyploid

    PubMed Central

    Zhang, Xiaoshen; Deng, Minjie; Fan, Guoqiang

    2014-01-01

    Paulownia fortunei is an ecologically and economically important tree species that is widely used as timber and chemical pulp. Its autotetraploid, which carries a number of valuable traits, was successfully induced with colchicine. To identify differences in gene expression between P. fortunei and its synthesized autotetraploid, we performed transcriptome sequencing using an Illumina Genome Analyzer IIx (GAIIx). About 94.8 million reads were generated and assembled into 383,056 transcripts, including 18,984 transcripts with a complete open reading frame. A conducted Basic Local Alignment Search Tool (BLAST) search indicated that 16,004 complete transcripts had significant hits in the National Center for Biotechnology Information (NCBI) non-redundant database. The complete transcripts were given functional assignments using three public protein databases. One thousand one hundred fifty eight differentially expressed complete transcripts were screened through a digital abundance analysis, including transcripts involved in energy metabolism and epigenetic regulation. Finally, the expression levels of several transcripts were confirmed by quantitative real-time PCR. Our results suggested that polyploidization caused epigenetic-related changes, which subsequently resulted in gene expression variation between diploid and autotetraploid P. fortunei. This might be the main mechanism affected by the polyploidization. Our results represent an extensive survey of the P. fortunei transcriptome and will facilitate subsequent functional genomics research in P. fortunei. Moreover, the gene expression profiles of P. fortunei and its autopolyploid will provide a valuable resource for the study of polyploidization. PMID:24663058

  19. Fauna Europaea: Mollusca - Bivalvia.

    PubMed

    Araujo, Rafael; de Jong, Yde

    2015-01-01

    Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. For the Mollusca-Bivalvia, data from 5 families (Margaritiferidae, Unionidae, Sphaeriidae, Cyrenidae, Dreissenidae) containing 55 species are included in this paper. European freshwater bivalves belong to the Orders Unionoida and Cardiida. All the European unionoids are included in the superfamily Unionoidea, the freshwater mussels or naiads. The European cardiids belong to the following three superfamilies: Cardioidea, Cyrenoidea and Dreissenoidea. Among the Unionoidea there are the most imperilled animal groups on the planet while the Cardioidea includes the cosmopolitan genus Pisidium, the Cyrenoidea the Asiatic clam (Corbiculafluminea) and the Dreissenoidea the famous invasive zebra mussel (Dreissenapolymorpha). Basic information is summarized on their taxonomy and biology. Tabulations include a complete list of the current estimated families, genera and species.

  20. Feeding rhythms of the green-lipped mussel, Perna viridis (Linnaeus, 1758) (Bivalvia: Mytilidae) during spring and neap tidal cycles.

    PubMed

    Wong, W H.; Cheung, S G.

    2001-02-20

    Food availability and feeding responses of the green mussel Perna viridis were investigated for two complete tidal cycles during both spring and neap tides. Temporal changes in total particulate matter (TPM), particulate inorganic matter (PIM) and particulate organic matter (POM), were smaller during neap than spring tides. Seston characteristics at different times of a tidal cycle were compared for both spring and neap tides. Only during spring tides were TPM and PIM significantly higher at high tides while POM remained relatively constant (P>0.05). The clearance rate of the mussels underwent temporal variations with tides, and was a negative power function of TPM and a positive linear function of f (organic content), during both spring and neap tides. f was the key factor influencing filtration rate, organic ingestion rate, absorption rate and absorption efficiency. All feeding rates increased linearly with increases in organic content. Pseudofaeces were produced only during spring but not neap tides. Feeding rates and absorption efficiency were highest at low and lowest at high tides (P<0.01). There was no significant temporal change in the wet weight and protein content of the crystalline style with the tidal regime. For the digestive gland, alpha-amylase activity was higher at spring than at neap tides, and higher during high tides in a tidal cycle. The digestive gland cellulase activity did not change significantly with the tides. For the crystalline style, both the activity of cellulase and alpha-amylase were not significantly different (P>0.05) between spring and neap tides. Tidal rhythms in feeding and digestion in this species were likely controlled by temporal variations in food availability in the seawater. By adjusting feeding rates and enzymatic activities, absorption in Perna viridis remained constant, irrespective of the changes in food availability.

  1. Unexpected co-occurrence of six bacterial symbionts in the gills of the cold seep mussel Idas sp. (Bivalvia: Mytilidae).

    PubMed

    Duperron, Sébastien; Halary, Sébastien; Lorion, Julien; Sibuet, Myriam; Gaill, Françoise

    2008-02-01

    Bathymodioline mussels occur in chemosynthesis-based ecosystems such as cold seeps, hydrothermal vents and organic debris worldwide. Their key adaptation to these environments is their association with bacterial endosymbionts which ensure a chemosynthetic primary production based on the oxidation of reduced compounds such as methane and sulfide. We herein report a multiple symbiosis involving six distinct bacterial 16S rRNA phylotypes, including two belonging to groups not yet reported as symbionts in mytilids, in a small Idas mussel found on carbonate crusts in a cold seep area located north to the Nile deep-sea fan (Eastern Mediterranean). Symbionts co-occur within hosts bacteriocytes based on fluorescence in situ hybridizations, and sequencing of functional genes suggests they have the potential to perform autotrophy, and sulfide and methane oxidation. Previous studies indicated the presence of only one or two symbiont 16S rRNA phylotypes in bathymodioline mussels. Together with the recent discovery of four bacterial symbionts in the large seep species Bathymodiolus heckerae, this study shows that symbiont diversity has probably been underestimated, and questions whether the common ancestor of bathymodioline mussels was associated with multiple bacteria.

  2. [Food effect on the physiological condition of the mussel Perna viridis (Bivalvia: Mytilidae), using the RNA/DNA ratio].

    PubMed

    Bracho, M A; Segnini de Bravo, M I; Viñoles, I; Chung, K S

    2000-12-01

    The green mussel, Perna viridis, became widespread in the northern coast of Sucre State since its arrival to Venezuela in 1993. RNA/DNA and Protein/DNA ratios were used to study the effect of starvation on its instantaneous growth. The mussels were collected in La Esmeralda and Chacopata, acclimatized in the laboratory for four weeks and maintained for another six weeks in two groups: one fed ad libitum and another without food (this later group was later fed for two additional weeks). Protein (colorimetric method), and nucleic acid concentrations (RNA and DNA, fluorometric method with ethidium bromide) were measured in adductor muscle, digestive gland and gills. The instantaneous growth was assessed using RNA/DNA and Protein/DNA rations. These indexes were always higher in the fed organisms. Animals from Chacopata were in better physiological condition that those from La Esmeralda during the abstinence time (six weeks). Muscle was the best tissue to determine instantaneous growth. The RNA/DNA ratio is a reliable index to determine the physiological condition and instantaneous growth of this species.

  3. [Effects of acclimation temperature on the growth of Perna viridis (Bivalvia: Mytilidae), using the RNA/DNA ratio].

    PubMed

    Viñoles, I del V; Segini de Bravo, M I; Bracho, M A; Chung, K S

    2000-12-01

    Temperature affects growth rate in aquatic organisms. This can be evaluated in short term using biochemical indexes (RNA/DNA and Protein/DNA). The effect of acclimatization temperature on the instantaneous growth and physiological condition of Perna viridis was studied in organisms collected in La Esmeralda, Sucre State (Venezuela) and taken to the laboratory, where groups of 100 organisms (size 3.0 - 3.5 cm, anteroposterior measurement) were acclimatized at 15, 20, 26 or 28 degrees C during four weeks. Later they were kept in a 60 liters aquarium for another six weeks under the same conditions. Each week, ten organisms per group were extracted to measure concentrations of RNA, DNA (by a fluorometric method with ethidium bromide) and proteins (by a colorimetric method), in tissues (digestive gland, adductor muscle and gills). Protein concentration was greater and highly significant at 15 degrees C for all studied tissues. The opposite was obtained with the RNA/DNA and Protein/DNA ratios: the greatest increase was observed at the highest temperature (28 degrees C) for all tissues. At the lowest temperature there was a tendency to reduce both indexes with time. Greater instantaneous growth can be expected at higher temperatures and 28 degrees C was optimal for growth in these specimens.

  4. Fauna Europaea: Mollusca – Bivalvia

    PubMed Central

    2015-01-01

    Abstract Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. For the Mollusca-Bivalvia, data from 5 families (Margaritiferidae, Unionidae, Sphaeriidae, Cyrenidae, Dreissenidae) containing 55 species are included in this paper. European freshwater bivalves belong to the Orders Unionoida and Cardiida. All the European unionoids are included in the superfamily Unionoidea, the freshwater mussels or naiads. The European cardiids belong to the following three superfamilies: Cardioidea, Cyrenoidea and Dreissenoidea. Among the Unionoidea there are the most imperilled animal groups on the planet while the Cardioidea includes the cosmopolitan genus Pisidium, the Cyrenoidea the Asiatic clam (Corbicula fluminea) and the Dreissenoidea the famous invasive zebra mussel (Dreissena polymorpha). Basic information is summarized on their taxonomy and biology. Tabulations include a complete list of the current estimated families, genera and species. PMID:26311403

  5. Evidence of genetic segregation in the apogamous fern species Cyrtomium fortunei (Dryopteridaceae).

    PubMed

    Ootsuki, Ryo; Sato, Hirotoshi; Nakato, Narumi; Murakami, Noriaki

    2012-09-01

    In apogamous ferns, all offspring from a parent are expected to be clonal. However, apogamous 'species' frequently demonstrate a large amount of morphological and genetic variations. Cyrtomium fortunei composed of four varieties (C. fortunei var. fortunei, var. clivicola, var. intermedium, and var. atropunctatum), is all reported to be apogamous triploids, but demonstrates large and continuous morphological variation. In previous studies, we showed that considerable genetic diversity was observed in many local populations of the apogamous fern 'species'. We hypothesized that genetic segregation has occurred, because neither sexual type nor intraspecific polyploidy have been observed in C. fortunei in Japan. Of 732 progeny examined (250 gametophytes and 482 sporophytes), obtained from a parental sporophyte whose pgiC genotype was estimated as aab, 11 (4.4%) gametophytes and 8 (1.7%) sporophytes showed a different genotype (aaa) from that of the parent sporophyte. We showed that genetic segregation occurs in apogamous C. fortunei in relatively high frequency. Moreover, we could first show that the segregation frequency in gametophytes is significantly higher than that in sporophytes of the next generation (χ² = 4.90, P = 0.027). It may suggest the existence of deleterious genes, which are expressed during the morphogenesis and growth of sporophytes.

  6. Development and characterization of 15 microsatellite markers for Cephalotaxus fortunei (Cephalotaxaceae)1

    PubMed Central

    Wang, Chunbo; Guo, Zhiyou; Huang, Xilian; Huang, Lu

    2016-01-01

    Premise of the study: To survey population variation and the adaptive evolution of Cephalotaxus fortunei (Cephalotaxaceae), an endemic and endangered conifer in China, microsatellite markers were developed and characterized for this species. Methods and Results: Based on the Fast Isolation by AFLP of Sequences COntaining repeats (FIASCO) protocol, 15 microsatellite markers were developed for C. fortunei, 13 of which were polymorphic within a sample of 75 individuals representing five natural populations. The number of alleles per locus ranged from one to seven. The expected and observed heterozygosities were 0.108–0.738 and 0.000–1.000, respectively. Ten polymorphic loci were also successfully amplified in C. oliveri. Conclusions: These polymorphic loci provide a valuable tool for population genetic analysis of C. fortunei, which will contribute to its management and conservation. PMID:27213121

  7. Assessment of toxicity of dissolved and microencapsulated biocides for control of the Golden Mussel Limnoperna fortunei.

    PubMed

    Calazans, Sávio Henrique C; Americo, Juliana Alves; da Costa Fernandes, Flavio; Aldridge, David C; de Freitas Rebelo, Mauro

    2013-10-01

    Biological invasions currently pose major threats to ecosystems worldwide. Invasive bivalves such as the Golden Mussel Limnoperna fortunei can act as 'environmental engineers', altering biogeochemistry, reducing biodiversity, and literally changing the landscape of aquatic environments. The risk that this mussel will invade the Amazon basin is a great concern for environmental authorities, especially because no efficient control methods presently exist. In this study, we tested new microencapsulated chemicals, along with the traditional dissolved chlorine and KCl, as alternatives to control L. fortunei infestation in industrial and water supply plants along rivers. Because these bivalves can close their valves when they sense toxic substances in the water, microencapsulation has improved the effectiveness of the chemicals in controlling L. fortunei, reducing variation in the application and increasing toxicity compared to dissolved chemicals. Microencapsulation should be seriously considered as an alternative to replace hazardous chlorine.

  8. A new marseillevirus isolated in Southern Brazil from Limnoperna fortunei

    PubMed Central

    dos Santos, Raíssa Nunes; Campos, Fabrício Souza; Medeiros de Albuquerque, Nathalia Rammé; Finoketti, Fernando; Côrrea, Rayra Almeida; Cano-Ortiz, Lucia; Assis, Felipe Lopes; Arantes, Thalita Souza; Roehe, Paulo Michel; Franco, Ana Cláudia

    2016-01-01

    Members of the family Marseilleviridae are giant viruses that have the ability to infect amoebas. Such viruses were initially described in 2009. Since then, this family has grown, and diverse members have been found in different environments and geographic locations. Previous phylogenetic analyses suggested the existence of four marseillevirus lineages. A fourth lineage was described with the discovery of the Brazilian marseillevirus (BrMr), isolated from Pampulha Lake, Brazil. Here we describe the isolation and characterization of the Golden marseillevirus (GMar), a new marseillevirus isolated from golden mussels (Limnoperna fortunei) in South of Brazil. This new representative of Marseilleviridae has circular, double-stranded (dsDNA) that contains 360, 610 base pairs and encodes 483 open read frames (ORFs). The complete virus genome was sequenced and phylogenic analyses indicated clear differences between this virus and other marseilleviruses. In addition, this is the only marseillevirus so far that has been isolated from mussels, and this report expands the diversity of environments from which giant viruses could be recovered. PMID:27739526

  9. Purification and characterization of windmill palm tree (Trachycarpus fortunei) peroxidase.

    PubMed

    Caramyshev, Alexei V; Firsova, Yuliya N; Slastya, Evgen A; Tagaev, Andrei A; Potapenko, Nataly V; Lobakova, Elena S; Pletjushkina, Olga Yu; Sakharov, Ivan Yu

    2006-12-27

    High peroxidase activity was demonstrated to be present in the leaf of several species of cold-resistant palms. Histochemical studies of the leaf of windmill palm tree (Trachycarpus fortunei) showed the peroxidase activity to be localized in hypoderma, epidermis, cell walls, and conducting bundles. However, chlorophyll-containing mesophyll cells had no peroxidase at all. The leaf windmill palm tree peroxidase (WPTP) was purified to homogeneity and had a specific activity of 6230 units/mg, RZ = 3.0, a molecular mass of 50 kDa, and an isoelectric point of pI 3.5. The electronic spectrum of WPTP with a Soret band at 403 nm was typical of plant peroxidases. The N-terminal amino acid sequence of WPTP was determined. The substrate specificity of WPTP was distinct from that of other palm peroxidases, and the best substrate for WPTP was 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid). The palm peroxidase showed an unusually high stability at elevated temperatures and high concentrations of guanidine.

  10. A new marseillevirus isolated in Southern Brazil from Limnoperna fortunei.

    PubMed

    Dos Santos, Raíssa Nunes; Campos, Fabrício Souza; Medeiros de Albuquerque, Nathalia Rammé; Finoketti, Fernando; Côrrea, Rayra Almeida; Cano-Ortiz, Lucia; Assis, Felipe Lopes; Arantes, Thalita Souza; Roehe, Paulo Michel; Franco, Ana Cláudia

    2016-10-14

    Members of the family Marseilleviridae are giant viruses that have the ability to infect amoebas. Such viruses were initially described in 2009. Since then, this family has grown, and diverse members have been found in different environments and geographic locations. Previous phylogenetic analyses suggested the existence of four marseillevirus lineages. A fourth lineage was described with the discovery of the Brazilian marseillevirus (BrMr), isolated from Pampulha Lake, Brazil. Here we describe the isolation and characterization of the Golden marseillevirus (GMar), a new marseillevirus isolated from golden mussels (Limnoperna fortunei) in South of Brazil. This new representative of Marseilleviridae has circular, double-stranded (dsDNA) that contains 360, 610 base pairs and encodes 483 open read frames (ORFs). The complete virus genome was sequenced and phylogenic analyses indicated clear differences between this virus and other marseilleviruses. In addition, this is the only marseillevirus so far that has been isolated from mussels, and this report expands the diversity of environments from which giant viruses could be recovered.

  11. Complete mitochondrial genome of the brown mussel Perna perna (Bivalve, Mytilidae).

    PubMed

    Uliano-Silva, Marcela; Americo, Juliana; Bastos, Alex Schomaker; Furtado, Carolina; Rebelo, Mauro de Freitas; Prosdocimi, Francisco

    2016-11-01

    The complete sequence of the brown mussel Perna perna mitochondrial genome is described in this article. It was sequenced in 1/11 of an Illumina HiSeq lane using Nextera multiplexing kit. The mitogenome was assembled using both (i) de novo assembly and (ii) referenced-based strategies with mitoMaker software. Perna perna mitogenome is a circular molecule of 18,415 bp in size, containing 12 protein-coding genes, 23 transfer RNAs, 2 ribossomal RNAs and several non-coding regions. As shown in the previous studies, Perna perna does not present the doubly uniparental inheritance system (DUI) of mitochondria and does not encode the ATPase8 gene, in accordance with other Mytilidae data.

  12. Influence of antifouling paint on freshwater invertebrates (Mytilidae, Chironomidae and Naididae): density, richness and composition.

    PubMed

    Fujita, D S; Takeda, A M; Coutinho, R; Fernandes, F C

    2015-11-01

    We conducted a study about invertebrates on artificial substrates with different antifouling paints in order to answer the following questions 1) is there lower accumulation of organic matter on substrates with antifouling paints, 2) is invertebrate colonization influenced by the release of biocides from antifouling paints, 3) is the colonization of aquatic invertebrates positively influenced by the material accumulated upon the substrate surface and 4) is the assemblage composition of invertebrates similar among the different antifouling paints? To answer these questions, four structures were installed in the Baía River in February 1st, 2007. Each structure was composed of 7 wood boards: 5 boards painted with each type of antifouling paints (T1, T2, T3, T4 and T5), one painted only with the primer (Pr) and the other without any paint (Cn). After 365 days, we observed a greater accumulation of organic matter in the substrates with T2 and T3 paint coatings. Limnoperna fortunei was recorded in all tested paints, with higher densities in the control, primer, T2 and T3. The colonization of Chironomidae and Naididae on the substrate was positively influenced by L. fortunei density. The non-metric multidimensional scaling (NMDS) of the invertebrate community provided evidence of the clear distinction of invertebrate assemblages among the paints. Paints T2 and T3 were the most similar to the control and primer. Our results suggest that antifouling paints applied on substrates hinder invertebrate colonization by decreasing the density and richness of invertebrates.

  13. A molecular phylogeny of the marine mussel genus Perna (Bivalvia: Mytilidae) based on nuclear (ITS1&2) and mitochondrial (COI) DNA sequences.

    PubMed

    Wood, Ann R; Apte, Smita; MacAvoy, Elizabeth S; Gardner, Jonathan P A

    2007-08-01

    A molecular phylogeny is presented for marine mussels of the genus Perna, based on nuclear (ITS1,ITS2) and mitochondrial (COI) DNA sequence data. The three generally recognised species (Perna viridis, Perna perna and Perna canaliculus) and one putative species (Perna picta) were each sampled from several locations within their known geographic distributions. A range of phylogenetic analyses was used to investigate the current taxonomic assignments, evolutionary relationships and the biogeographical history of the genus. The different analyses produced similar, well supported topologies and verified the monophyly of the genus with respect to five mytilid outgroup species. P. perna (Atlantic), P. viridis (Indo-West Pacific), and P. canaliculus (New Zealand) each formed distinct clades, confirming their specific status. Putative P. picta from North Africa clustered within the P. perna clade and is not regarded as a separate species. P. perna and P. canaliculus were the most closely related of the three species. Possible biogeographic explanations for the present species distributions are evaluated.

  14. [Effect of copper ions on spatial density of NO-synthase-positive cells in the intestine of the mussel Crenomytilus grayanus (Mollusca: Bivalvia: Mytilidae) a histochemical study].

    PubMed

    Pimenova, E A

    2010-01-01

    By the histochemical method of detection of NADPH-diaphorase (NADPH-d) (EC 1.6.99.1) the state of nitroxidergic enteric nervous system of the mussel Crenomytilus grayanus was studied under conditions of an increased copper concentration in water. Under the action of copper ions the density of distribution of NADPH-d-positive cells has been established to be changed as compared with control throughout 28 days. A sharp rise of proportion of the labeled cells and their enzyme activity was noted after one day of the experiment. The labeled bipolar cells were of dark blue color and were located within the epithelium. There were revealed numerous nerve fibers penetrating the intestinal epithelium throughout its entire length as well as bipolar nerve cells in epithelium of the minor typhlosole and of crystalline style sac; in control molluscs the NADPH-d-positive cells in these parts were absent. After 7 days the difference between control and experimental decreased and remained at this level after 14 days, while after 21 days of exposition the proportion of labeled cells in the experimental mussels was lower than in control, but increased again after 28 days. It is suggested that nitric oxide is an important protective factor of the intestinal epithelium of the mussel C. grayanus and participates in adaptation of this mollusc to action of the elevated concentration of copper ions in water.

  15. [Growth and survival of the green mussel P. viridis (Bivalvia: Mytilidae) in bottom culture conditions in Turpialito, Golfo de Cariaco, Venezuela].

    PubMed

    Acosta, Vanessa; Montes, Marbelis; Cortez, Roraysi; Guevara, Miguel; Lodeiros, César

    2012-12-01

    Mussels represent one of the most important mollusk species for culture activities around the world, and their growth may depend on the culture system used and locality. In this study, we evaluated the growth of Perna viridis in bottom culture to test its performance when using natural food, and to decide its use as a culture species in the Gulf of Cariaco. For this, mussel seeds (35.81 +/- 1.41 mm in length) were obtained in the locality of Guaca (North coast of Sucre state) and transferred to the Hydrobiological Station of Turpialito, Gulf of Cariaco, Sucre state, Venezuela, where they were planted in "Spanish baskets" to evaluate their growth between July 2007 and February 2008. Monthly survival was determined and the maximum shell length, dry mass of muscle and remains tissues of the gonad. The environmental parameters (water temperature, salinity, dissolved oxygen, chlorophyll a, total seston and organic fraction), in the cultivation area were determined every 15 days. Monthly measurements were made of proteins, lipids and carbohydrates to seston. During the entire study the mussels showed continued growth, ultimately reaching a maximum length of 78.7 +/- 4.43 mm. However, the growth rate of the dry mass of somatic (muscle, other tissue) and reproductive tissues showed variability throughout the study, and observed a significant increase by the end of the experiment. The observed variations in the growth rate of the reproductive tissue mass depended on the reserves accumulated and food offered by the environment. The organic seston throughout the experience showed an independence of temperature and chlorophyll a values; this one maintained values above 1 mg/L, thus forming the main food resource for mussels. The high content of proteins, lipids and carbohydrates observed in the seston at the end of the study, might be mainly associated with coastal upwelling, which provides a great food contribution of phytoplankton and organic type. The high survival rate (>80%), increase in the length of the shell and the high gonad production, suggests an excellent physiological condition of P. viridis, related to the availability and quality of food particularly the organic type present in the medium. We concluded that the bottom culture can provide an alternative aquaculture production in the Gulf of Cariaco.

  16. Scorched mussels (Brachidontes spp., Bivalvia: Mytilidae) from the tropical and warm-temperate southwestern Atlantic: the role of the Amazon River in their speciation.

    PubMed

    Trovant, Berenice; Basso, Néstor G; Orensanz, José María; Lessa, Enrique P; Dincao, Fernando; Ruzzante, Daniel E

    2016-03-01

    Antitropicality is a distribution pattern where closely related taxa are separated by an intertropical latitudinal gap. Two potential examples include Brachidontes darwinianus (south eastern Brazil to Uruguay), considered by some authors as a synonym of B. exustus (Gulf of Mexico and the Caribbean), and B. solisianus, distributed along the Brazilian coast with dubious records north of the intertropical zone. Using two nuclear (18S and 28S rDNA) and one mitochondrial gene (mtDNA COI), we aimed to elucidate the phylogeographic and phylogenetic relationships among the scorched mussels present in the warm-temperate region of the southwest Atlantic. We evaluated a divergence process mediated by the tropical zone over alternative phylogeographic hypotheses. Brachidontes solisianus was closely related to B. exustus I, a species with which it exhibits an antitropical distribution. Their divergence time was approximately 2.6 Ma, consistent with the intensification of Amazon River flow. Brachidontes darwinianus, an estuarine species is shown here not to be related to this B. exustus complex. We suspect ancestral forms may have dispersed from the Caribbean to the Atlantic coast via the Trans-Amazonian seaway (Miocene). The third species, B rodriguezii is presumed to have a long history in the region with related fossil forms going back to the Miocene. Although scorched mussels are very similar in appearance, their evolutionary histories are very different, involving major historical contingencies as the formation of the Amazon River, the Panama Isthmus, and the last marine transgression.

  17. Chromosomal mapping of rRNA genes, core histone genes and telomeric sequences in Brachidontes puniceus and Brachidontes rodriguezi (Bivalvia, Mytilidae)

    PubMed Central

    2010-01-01

    Background Chromosome rearrangements are an important part of the speciation process in many taxa. The study of chromosome evolution in bivalves is hampered by the absence of clear chromosomal banding patterns and the similarity in both chromosome size and morphology. For this reason, obtaining good chromosome markers is essential for reliable karyotypic comparisons. To begin this task, the chromosomes of the mussels Brachidontes puniceus and B. rodriguezi were studied by means of fluorochrome staining and fluorescent in situ hybridization (FISH). Results Brachidontes puniceus and B. rodriguezi both have 2n = 32 chromosomes but differing karyotype composition. Vertebrate-type telomeric sequences appear at both ends of every single chromosome. B. puniceus presents a single terminal major rRNA gene cluster on a chromosome pair while B. rodriguezi shows two. Both mussels present two 5S rDNA and two core histone gene clusters intercalary located on the long arms of two chromosome pairs. Double and triple-FISH experiments demonstrated that one of the 5S rDNA and one of the major rDNA clusters appear on the same chromosome pair in B. rodriguezi but not in B. puniceus. On the other hand, the second 5S rDNA cluster is located in one of the chromosome pairs also bearing one of the core histone gene clusters in the two mussel species. Conclusion Knowledge of the chromosomal distribution of these sequences in the two species of Brachidontes is a first step in the understanding of the role of chromosome changes on bivalve evolution. PMID:21143946

  18. Integrated Use of Biomarkers (O : N Ratio and Acetylcholinesterase Inhibition) on Aulacomya ater (Molina, 1782) (Bivalvia: Mytilidae) as a Criteria for Effects of Organophosphate Pesticide Exposition

    PubMed Central

    Führer, Eduardo; Rudolph, Anny; Espinoza, Claudio; Díaz, Rodrigo; Gajardo, Marisol; Camaño, Nuria

    2012-01-01

    The effect of residual concentrations of organophosphate pesticide chlorpyrifos (Lorsban 4E) on the activity of the acetylcholinesterase enzyme and oxygen : nitrogen ratio in the mussel Aulacomya ater was analyzed. Toxicity tests show a sensitivity to the pesticide in the bivalve estimated at 16 μg L−1 (LC50−96 hours). Concentrations between 0.2 and 1.61 μg L−1 were able to inhibit significantly the AChE activity, and concentrations between 0.8 and 1.61 μg L−1 stimulate ammonia excretion and decrease oxygen : ammonia-N (O : N) ratio, with respect to the control group. A. ater proved to be a species sensitive to pesticide exposure and easy to handle in lab conditions. Thus, it is recommended as a bioindicator for use in programs of environmental alertness in the Eastern South Pacific coastal zone. PMID:22619673

  19. Lysosomal membrane stability, phagocytosis and tolerance to emersion in the mussel Perna viridis (Bivalvia: Mytilidae) following exposure to acute, sublethal, copper.

    PubMed

    Nicholson, S

    2003-08-01

    The mytilid mussel Perna viridis is distributed throughout the Indo-Pacific region and is potentially a suitable candidate for biological effects (biomarker) monitoring in the subtropics. A suite of cytological and physiological responses to acute (48-72 h) copper exposures of 50-200 microgl(-1) were assessed in order to determine the suitability of P. viridis for marine pollution monitoring. Copper elicited significant destabilisation of the haemocyte lysosomal membranes and also impaired phagocytosis. Survival during emersion following exposure to copper was not related to the experimental copper exposures suggesting that higher metal concentrations may be required to interfere with anaerobic enzymes responsible for suppression of metabolism. Based on this preliminary study, cytological biomarkers evaluated in the haemocytes extracted from P. viridis should prove an effective non-destructive means of assessing metal pollution throughout the mussels subtropical range.

  20. Toxicity of Neem's oil, a potential biocide against the invasive mussel Limnoperna fortunei (Dunker 1857).

    PubMed

    Pereyra, Patricio J; Rossini, Gustavo B; Darrigran, Gustavo

    2012-12-01

    The golden mussel Limnoperna fortunei (Dunker 1857) is one of the most distributed Nuisance Invasive Species (NIS) in South America, and a threat of great concern for the industry of the area. In this study, we carried out toxicity tests made with a Neem's oil solution with L. fortunei larvae and benthonic adults (7, 13 and 19 ± 1 mm). Tests with non-target species (Daphnia magna, Lactuca sativa and Cnesterodon decemmculatus) were also made with the aim to evaluate the potential toxicity of the Neem's solution in the environment. The LC(100) of Neem's solution obtained for larvae was 500 µl/L, a value much higher than the one obtained for D. magna and C. decemmaculatus. Thus, we recommend that it should not be used in open waters. However, since the adults were killed in 72 h and the larvae in 24 h, this product can be used in closed systems, in man-made facilities.

  1. Development of microsatellite markers for the Korean Mussel, Mytilus coruscus (Mytilidae) using next-generation sequencing.

    PubMed

    An, Hye Suck; Lee, Jang Wook

    2012-01-01

    Mytilus coruscus (family Mytilidae) is one of the most important marine shellfish species in Korea. During the past few decades, this species has become endangered due to the loss of habitats and overfishing. Despite this species' importance, information on its genetic background is scarce. In this study, we developed microsatellite markers for M. coruscus using next-generation sequencing. A total of 263,900 raw reads were obtained from a quarter-plate run on the 454 GS-FLX titanium platform, and 176,327 unique sequences were generated with an average length of 381 bp; 2569 (1.45%) sequences contained a minimum of five di- to tetra-nucleotide repeat motifs. Of the 51 loci screened, 46 were amplified successfully, and 22 were polymorphic among 30 individuals, with seven of trinucleotide repeats and three of tetranucleotide repeats. All loci exhibited high genetic variability, with an average of 17.32 alleles per locus, and the mean observed and expected heterozygosities were 0.67 and 0.90, respectively. In addition, cross-amplification was tested for all 22 loci in another congener species, M. galloprovincialis. None of the primer pairs resulted in effective amplification, which might be due to their high mutation rates. Our work demonstrated the utility of next-generation 454 sequencing as a method for the rapid and cost-effective identification of microsatellites. The high degree of polymorphism exhibited by the 22 newly developed microsatellites will be useful in future conservation genetic studies of this species.

  2. The scientific literature on Limnoperna fortunei (Dunker 1857) from 1982 to 2012.

    PubMed

    Barbosa, Fabiana G

    2014-09-01

    Limnoperna fortunei (golden mussel) is a freshwater bivalve native to Southeast Asia, but is becoming an invasive species in several aquatic ecosystems in the world. In this study, a scientometric analysis was performed to identify the patterns, trends and gaps of knowledge for this invasive species. A survey of the published literature was conducted using the database of the Thomson Institute for Scientific Information (ISI). A total of 107 papers were surveyed that were published between 1982 and 2012 in 60 journals. The number of papers on L. fortunei over the years has increased, especially within the last eight years of the study period. Argentina, Brazil, and Japan are the countries that contributed the most papers to the literature on invasive bivalve. The majority of papers were field-observational studies. Among some important gaps that need to be addressed are the relatively small number and/or lack of studies conducted in the native countries and in countries invaded by L. fortunei, the lack of internationally collaborative publications in these countries, as well as a low number of internationally collaborative studies.

  3. Physiological response of Cu and Cu mine tailing remediation of Paulownia fortunei (Seem) Hemsl.

    PubMed

    Jiang, Zao-Fa; Huang, Su-Zhen; Han, Yu-Lin; Zhao, Jiu-Zhou; Fu, Jia-Jia

    2012-04-01

    The physiological responses and Cu accumulation of Paulownia fortunei (Seem) Hemsl. were studied under 15.7-157 μmol L(-1) Cu treatments in liquid culture for 14 days; the impacts of Cu concentration in the seedlings were evaluated under Cu mine tailing culture with acetic acid and EDTA treatment for 60 days. Results showed that the concentrations of Chl-a, Chl-b and Carotenoids significantly increased (p < 0.05) at 15.7-78.7 μmol L(-1)Cu treatment and significantly decreased at 157 μmol L(-1) treatment after 14 days of Cu exposure. The activities of superoxide dismutase (SOD) and catalase (CAT) significantly increased as Cu levels were enhanced and the activities of both SOD and CAT under 157 μmol L(-1) Cu stress were 2.9 and 1.9 times higher than that of control, respectively. The concentrations of proline and soluble sugars in the leaves of P. fortunei significantly increased as the Cu concentrations were elevated. Cu concentrations in roots, stems and leaves of P. fortunei increased significantly as Cu levels increased and reached 1911, 101 and 93 μg g(-1) dry weights (DW) at 157 μmol L(-1) Cu treatment, respectively. The seedlings of P. fortunei cultivated in Cu tailing experienced unsuccessful growth and loss of leaves in all treatments due to poor nutrition of the Cu tailing. The dry weight of P. fortunei increased under all the treatments of acetic acid after 60 days exposure. However, dry weight significantly decreased under both levels of EDTA. The Cu concentrations increased significantly in roots and decreased in leaves when each was treated with both concentrations of acetic acid. The Cu concentrations in the roots, stems and leaves increased significantly, and the concentrations of Cu in the stems and leaves under the treatment of 2 μmol L(-1) EDTA reached 189.5 and 763.1 μg g(-1) DW, respectively. The result indicated that SOD, CAT, proline and soluble sugars played an important role in coping with the oxidative stress of copper. Acetic acid

  4. Comparative Analysis and Identification of miRNAs and Their Target Genes Responsive to Salt Stress in Diploid and Tetraploid Paulownia fortunei Seedlings.

    PubMed

    Fan, Guoqiang; Li, Xiaoyu; Deng, Minjie; Zhao, Zhenli; Yang, Lu

    2016-01-01

    Salt stress is a global environmental problem that affects plant growth and development. Paulownia fortunei is an adaptable and fast-growing deciduous tree native to China that is environmentally and economically important. MicroRNAs (miRNAs) play important regulatory roles in growth, development, and stress responses in plants. MiRNAs that respond to biotic stresses have been identified; however, how miRNAs in P. fortunei respond to salt stress has not yet been reported. To identify salt-stress-responsive miRNAs and predict their target genes, four small RNA and four degradome libraries were constructed from NaCl-treated and NaCl-free leaves of P. fortunei seedlings. The results indicated that salt stress had different physiological effects on diploid and tetraploid P. fortunei. We detected 53 conserved miRNAs belonging to 17 miRNA families and 134 novel miRNAs in P. fortunei. Comparing their expression levels in diploid and tetraploid P. fortunei, we found 10 conserved and 10 novel miRNAs that were significantly differentially expressed under salt treatment, among them eight were identified as miRNAs probably associated with higher salt tolerance in tetraploid P. fortunei than in diploid P. fortunei. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to predict the functions of the target genes of the conserved and novel miRNAs. The expressions of 10 differentially expressed miRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). This is the first report on P. fortunei miRNAs and their target genes under salt stress. The results provided information at the physiological and molecular levels for further research into the response mechanisms of P. fortunei to salt stress.

  5. Comparative Analysis and Identification of miRNAs and Their Target Genes Responsive to Salt Stress in Diploid and Tetraploid Paulownia fortunei Seedlings

    PubMed Central

    Fan, Guoqiang; Li, Xiaoyu; Deng, Minjie; Zhao, Zhenli; Yang, Lu

    2016-01-01

    Salt stress is a global environmental problem that affects plant growth and development. Paulownia fortunei is an adaptable and fast-growing deciduous tree native to China that is environmentally and economically important. MicroRNAs (miRNAs) play important regulatory roles in growth, development, and stress responses in plants. MiRNAs that respond to biotic stresses have been identified; however, how miRNAs in P. fortunei respond to salt stress has not yet been reported. To identify salt-stress-responsive miRNAs and predict their target genes, four small RNA and four degradome libraries were constructed from NaCl-treated and NaCl-free leaves of P. fortunei seedlings. The results indicated that salt stress had different physiological effects on diploid and tetraploid P. fortunei. We detected 53 conserved miRNAs belonging to 17 miRNA families and 134 novel miRNAs in P. fortunei. Comparing their expression levels in diploid and tetraploid P. fortunei, we found 10 conserved and 10 novel miRNAs that were significantly differentially expressed under salt treatment, among them eight were identified as miRNAs probably associated with higher salt tolerance in tetraploid P. fortunei than in diploid P. fortunei. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to predict the functions of the target genes of the conserved and novel miRNAs. The expressions of 10 differentially expressed miRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). This is the first report on P. fortunei miRNAs and their target genes under salt stress. The results provided information at the physiological and molecular levels for further research into the response mechanisms of P. fortunei to salt stress. PMID:26894691

  6. [Antimicrobial activity of the epicarp of the fruits of Paulownia fortunei and Paulownia tomentosa].

    PubMed

    Cercós, A P

    1982-01-01

    One antimicrobial substance was obtained from the epicarp of the fruits of Paulownia fortunei and Paulownia tomentosa. Other parts of the fruits and leaves had no detectable antimicrobial activity. The substance was active in vitro for Staphylococcus aureus and Bacillus subtilis while it had lower activity for Saccharomyces carlsbergensis and the lowest was for Escherichia coli. The active material was extracted with organic solvents (ether, ethanol and acetone). The activity "in vitro" was demonstrated by the method of dilution in nutrient agar media. The active substance looked as a resin and was insoluble in water at neutral or acid pH. It was very soluble in strong alkaline pH solution.

  7. Changes in the drift and the settlement of the freshwater mussel Limnoperna fortunei along a headrace channel.

    PubMed

    Nakano, Daisuke; Kobayashi, Takuya; Sakaguchi, Isamu

    2012-01-01

    The nuisance species Limnoperna fortunei is a freshwater mussel whose infestations have harmed water intake facilities, such as water supply systems. We investigated the changes in the drift and the settlement of L. fortunei along a headrace channel. The densities of the drift and the settlement both decreased dramatically with the downstream distance from the L. fortunei source (a reservoir). In comparison with larval densities in the reservoir, drift densities decreased by 10 to 25% at 0.5 km downstream from the reservoir, and were less than 2% at sites more than 4.8 km downstream. Although larval densities at midnight (0:00-2:00) were approximately 1.5 times higher than those at noon (12:00-14:00) in a shallow layer (3 m depth) of the reservoir, we found no diurnal variation of drift densities in the headrace channel. Settlement densities at the site nearest the intake gate were much higher than those of the other sites further downstream in the headrace channel. The L. fortunei adult population in the channel could reduce drift individuals by attracting the larva. The attraction probably induces the massive aggregation at the location of the channel immediately below the drift source, resulting in biofouling.

  8. Quality of trace element contaminated soils amended with compost under fast growing tree Paulownia fortunei plantation.

    PubMed

    Madejón, P; Xiong, J; Cabrera, F; Madejón, E

    2014-11-01

    The use of fast growing trees could be an alternative in trace element contaminated soils to stabilize these elements and improve soil quality. In this study we investigate the effect of Paulownia fortunei growth on trace element contaminated soils amended with two organic composts under semi-field conditions for a period of 18 months. The experiment was carried out in containers filled with tree different soils, two contaminated soils (neutral AZ and acid V) and a non contaminated soil, NC. Three treatments per soil were established: two organic amendments (alperujo compost, AC, and biosolid compost, BC) and a control without amendment addition. We study parameters related with fertility and contamination in soils and plants. Paulownia growth and amendments increased pH in acid soils whereas no effect of these factors was observed in neutral soils. The plant and the amendments also increased organic matter and consequently, soil fertility. Positive results were also found in soils that were only affected by plant growth (without amendment). A general improvement of "soil biochemical quality" was detected over time and treatments, confirming the positive effect of amendments plus paulownia. Even in contaminated soils, except for Cu and Zn, trace element concentrations in leaves were in the normal range for plants. Results of this mid-term study showed that Paulownia fortunei is a promising species for phytoremediation of trace element polluted soils.

  9. Effects of total flavonoids from Drynaria fortunei on the proliferation and osteogenic differentiation of rat dental pulp stem cells.

    PubMed

    Huang, Xiao-Fei; Yuan, Su-Jian; Yang, Cheng

    2012-09-01

    Dental pulp stem cells (DPSCs) have the potential to form bone, nerve and fat, and are a candidate for use in regenerative medicine. Previous studies indicated that total flavonoids from Drynaria fortunei show a stimulative effect on the proliferation and osteogenic differentiation of osteoblastic MC3T3-E1 cells in vitro. This study aimed to investigate the effect of total flavonoids from Drynaria fortunei on the proliferation and osteogenic differentiation of rat DPSCs, and to further clarify the mechanisms involved. DPSCs were isolated by enzymatic digestion and identified using the CD44, CD29 and CD34 markers by immunohistochemistry, and exposed to 0.01, 0.05 and 0.1 g/l total flavonoids from Drynaria fortunei media. Total flavonoids from Drynaria fortunei promoted the proliferation of DPSCs in a dose-dependent manner and this effect may depend on the shortening of the G0/G1 phase and promotion of the S phase. Compared with the control group, the levels of alkaline phosphatase (ALP) and the expression of osteogenic genes increased with the concentrations of total flavonoids from Drynaria fortunei, and the volume and number of calcified nodules in the Drynaria groups was bigger compared to the control group. These results suggest that total flavonoid from Drynaria fortunei directly stimulates DPSC proliferation and osteogenic differentiation, and may serve as a new promising candidate drug for dental tissue engineering and bone regeneration.

  10. Amino acid sequence of anionic peroxidase from the windmill palm tree Trachycarpus fortunei.

    PubMed

    Baker, Margaret R; Zhao, Hongwei; Sakharov, Ivan Yu; Li, Qing X

    2014-12-10

    Palm peroxidases are extremely stable and have uncommon substrate specificity. This study was designed to fill in the knowledge gap about the structures of a peroxidase from the windmill palm tree Trachycarpus fortunei. The complete amino acid sequence and partial glycosylation were determined by MALDI-top-down sequencing of native windmill palm tree peroxidase (WPTP), MALDI-TOF/TOF MS/MS of WPTP tryptic peptides, and cDNA sequencing. The propeptide of WPTP contained N- and C-terminal signal sequences which contained 21 and 17 amino acid residues, respectively. Mature WPTP was 306 amino acids in length, and its carbohydrate content ranged from 21% to 29%. Comparison to closely related royal palm tree peroxidase revealed structural features that may explain differences in their substrate specificity. The results can be used to guide engineering of WPTP and its novel applications.

  11. Impact of the invasive mussel Limnoperna fortunei on glyphosate concentration in water.

    PubMed

    Di Fiori, Eugenia; Pizarro, Haydée; dos Santos Afonso, María; Cataldo, Daniel

    2012-07-01

    The use of glyphosate has increased dramatically during the past years around the world. Microbial communities are altered when glyphosate reaches water bodies. The freshwater golden mussel Limnoperna fortunei is an invasive species that has rapidly dispersed since it was introduced in Argentina two decades ago. Mussels alter aquatic conditions through their filtrating activity by increasing water clarity and nutrient recycling. We aim to evaluate the potential capacity of the golden mussel to reduce glyphosate concentration in water, in laboratory conditions. Firstly, the evasive response of mussels to glyphosate (10, 20, and 40 mg l⁻¹) was evaluated and a toxicity test was carried out for these concentrations. A three-week experiment was then performed to assess glyphosate variation under mussel presence for two mussel sizes. Finally, mussels' role on glyphosate concentration was evaluated considering different mussel parts (living organisms and empty shells) through another three-week experiment. Laboratory experiments were performed in triplicate using 2-l microcosms. An initial glyphosate concentration between 16 and 19 mg l⁻¹ was used, and when mussels or valvae were added, 20 organisms per aquaria were used. Samples were obtained at days 0, 1, 2, 4, 8, 14, and 21. Glyphosate decreased by 40% under large mussel presence in both experiments, and was reduced by 25% in empty shell treatments. We believe that part of the herbicide that disappears from the water column is adsorbed in valvae surface, while another proportion is being mineralized by microbial communities in shells' biofilm. The mechanisms by which living mussels increase glyphosate dissipation would be degradation, possibly mediated by bacteria associated to mussel's metabolism. Glyphosate half-life depended on mussel and valvae presence and varied with mussel size. L. fortunei presence (either alive or as empty valvae) alters glyphosate concentration in water. We provide preliminary

  12. Substrate-borne vibrations induce behavioral responses in the leaf-dwelling cerambycid, Paraglenea fortunei.

    PubMed

    Tsubaki, Remi; Hosoda, Naoe; Kitajima, Hiroshi; Takanashi, Takuma

    2014-12-01

    Many insects utilize substrate-borne vibrations as a source of information for recognizing mates or predators. Among various substrates, plant leaves are commonly used for transmitting and receiving vibrational information. However, little is known about the utilization of vibrations by leaf-dwelling insects, especially coleopteran beetles. We conducted two experiments to examine the response of the leaf-dwelling cerambycid beetle, Paraglenea fortunei, to substrate-borne vibrations. We recorded and analyzed vibrations of host plant leaves from four different sources: wind (0.5 m/s), a beetle during landing, a walking beetle, and a beetle walking in the wind (0.5 m/s). We then measured the behavioral thresholds, the lowest amplitudes that induce behavioral responses, from beetles walking and resting on horizontal and vertical substrates with pulsed vibrations ranging from 20 Hz to 1 kHz. The vibrational characteristics of biotic and abiotic stimuli clearly differed. Beetle-generated vibrations (landing, walking, and walking in the wind) were broadly high in the low-frequency components above ∼30 Hz, while wind-generated vibrations showed a dominant peak at ∼30 Hz and a steep decrease thereafter. Among four situations, beetles walking on horizontal substrates showed lowest thresholds to vibrations of 75-500 Hz, which are characteristic of beetle-generated vibrations. Given that P. fortunei beetles are found on horizontal leaf surfaces of the host plant, vibrations transmitted though horizontal substrates may induce a strong freeze response in walking beetles to detect conspecifics or heterospecifics. Our findings provide evidence that leaf-dwelling beetles can discriminate among biotic and abiotic factors via differences in vibrational characteristics.

  13. A New Oidiodendron maius Strain Isolated from Rhododendron fortunei and its Effects on Nitrogen Uptake and Plant Growth

    PubMed Central

    Wei, Xiangying; Chen, Jianjun; Zhang, Chunying; Pan, Dongming

    2016-01-01

    A new mycorrhizal fungal strain was isolated from hair roots of Rhododendron fortunei Lindl. grown in Huading Forest Park, Zhejiang Province, China. Morphological characterization and internal transcribed spacer rDNA analysis suggested that it belongs to Oidiodendron maius Barron, and we designated it as strain Om19. Methods for culturing Om19 were established, and the ability of Om19 to form mycorrhizae on R. fortunei was evaluated in a peat-based substrate. Microscopic observations showed hyaline hyphae on the surface of hair roots and crowded hyphal complexes (hyphal coils) inside root cortical cells of R. fortunei after inoculation, indicating that the roots were well colonized by Om19. In a second experiment, fresh and dry weight of R. fortunei 2 months after Om19 inoculation were greater than uninoculated plants, and the total nitrogen absorbed by plants inoculated with Om19 was greater than the uninoculated controls. qRT-PCR analysis of five genes related to N uptake and metabolism (two nitrate transporters, an ammonium transporter, glutamine synthetase, and glutamate synthase) showed that these genes were highly upregulated with twofold to ninefold greater expression in plants inoculated with Om19 compared to uninoculated plants. In the third experiment, Om19 was inoculated into the peat-based substrate for growing Formosa azalea (Rhododendron indica ‘Formosa’). ‘Formosa’ azalea plants grown in the inoculated substrate had larger canopies and root systems compared to uninoculated plants. Our results show that Om19 could be an important microbial tool for improving production of Rhododendron plants. PMID:27602030

  14. Mitogenomics reveals two subspecies in Coelomactra antiquata (Mollusca: Bivalvia).

    PubMed

    Meng, Xueping; Shen, Xin; Zhao, Nana; Tian, Mei; Liang, Meng; Hao, Jue; Cheng, Hanliang; Yan, Binlun; Dong, Zhiguo; Zhu, Xiaoling

    2013-04-01

    The mitochondrial genome sequence of Coelomactra antiquata (Mollusca: Bivalvia) in Zhangzhou (zz-mtDNA) was fully sequenced and compared with that in Rizhao (rz-mtDNA) in this study. A tRNA (tRNA (Met) ) located between tRNA (Ala) and cox1 genes was identified in zz-mtDNA but not in rz-mtDNA. The largest non-coding region (NCR; MNR) contained 11 copies 99nt tandem repeat sequences exclusively in rz-mtDNA, while the second largest NCR with 400 bp between tRNA (Ala) and tRNA (Met) in zz-mtDNA was absent in rz-mtDNA. Secondary structures of ZZ and RZ C. antiquata rRNAs are significantly different. The mitochondrial genomic characteristics clearly indicate that there are at least two subspecies in C. antiquata.

  15. Biochemical response of the mussel Mytilus coruscus (Mytiloida: Mytilidae) exposed to in vivo sub-lethal copper concentrations

    NASA Astrophysics Data System (ADS)

    Li, Yifeng; Gu, Zhongqi; Liu, Hong; Shen, Heding; Yang, Jinglong

    2012-09-01

    Many aquatic organisms are negatively affected by exposure to high copper concentrations. We investigated the biochemical response of the mussel Mytilus coruscus (Mytiloida: Mytilidae) to copper exposure. In vivo bioassays using M. coruscus and different copper concentrations were conducted. The activity of six biomarkers, namely superoxide dismutase (SOD), catalase (CAT), acid phosphatase (ACP), alkaline phosphatase (AKP), glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) were measured. Survival rates decreased with increased copper concentrations and exposure times. The LC50 values at 48, 72, and 96 h exposure were 0.48, 0.37, and 0.32 mg/L, respectively. Within digestive glands, CAT activity increased with increasing Cu concentrations. The activity of AKP showed no significant change, while the remaining four enzymes showed decreasing activity with increasing Cu concentrations. Within the gills, AKP activity increased when the Cu concentration was 0.05 mg/L, but showed no significant changes at higher concentrations. Activity of CAT and ACP within gills tended to decrease with increasing Cu concentration. The activity of SOD and GPT decreased at an exposure concentration of 0.2 mg/L. GOT activity within gills decreased at 0.1 mg/L and increased at an exposure concentration of 0.2 mg/L. Within the adductor muscle, AKP activity increased at 0.05 mg/L but did not change at higher exposure concentrations. ACP activity within adductor muscle tissue showed no change, while activities of CAT, GOT and GPT decreased with increasing Cu concentrations. SOD activity within the adductor muscle tissue significantly decreased at the 0.02, 0.05 and 0.2 mg/L exposure concentrations. Our results show tissue specific differences for the six biomarkers in for M. coruscus. Our findings provide the basis for the establishment of reference activity levels against which biomarker changes can be estimated, and are essential preliminary steps in development

  16. [Complex effects of simulated acid rain and Cu on the physiological characteristics of Paulownia fortunei and its detoxification mechanism].

    PubMed

    Wang, Jiang; Zhang, Chong-Bang; Ke, Shi-Sheng; Qian, Bao-Ying

    2010-03-01

    A pot experiment was conducted to study the effects of simulated acid rain (pH 4.0, 5.0) and Cu (0-200 mg x kg(-1)) on the physiological characteristics of Paulownia fortunei and its detoxification mechanism. With no Cu addition, the leaf chlorophyll, carotenoid, O2 division by, H2O2, and MDA contents of P. fortunei had no significant differences between the two acid rain treatments. However, with the addition of 100 and 200 mg Cu x kg(-1), the chlorophyll and carotenoid contents of treatment pH 4.0 were lower, while the O2 divided by, H2O2 and MDA contents were higher thanthose of treatment pH 5.0. The chlorophyll a/b ratio of treatments Cu was higher than that of the control. The leaf Cu content decreased obviously with the increasing acidity of stimulated acid rain, but the root Cu content was in reverse. With increasing Cu addition, both the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the total contents of phytochelatins (PCs) and glutathione (GSH) in treatment pH 5.0 increased, while the activities of SOD, POD, CAT and APX in treatment pH 4.0 decreased after an initial increase, and the total contents of glutathione (GSH) decreased greatly in treatment 200 mg Cu x kg(-1). All of these demonstrated that the oxidative stress of high Cu concentration to P. fortunei was aggravated by stimulated acid rain.

  17. [Taxonomic diversity of parasites in agnathans and fishes from the Volga River basin. VI. Acanthocephala, Hirudinea and Bivalvia].

    PubMed

    Molodozhnikova, N M; Zhokhov, A E

    2008-01-01

    The checklist of Acanthocephala, Hirudinea, and Bivalvia parasitizing agnathans and fishes in the Volga River basin is presented. Hosts and areas of distribution are indicated for each parasites species. The checklist includes 10 species of acanthocephalans, 7 species of leeches, and 9 species of Bivalvia (at the glochidium stage) from 45 fish species. None of the given parasite species is alien for the Volga River basin.

  18. Titanium dioxide nanoparticles induce genotoxicity but not mutagenicity in golden mussel Limnoperna fortunei.

    PubMed

    Girardello, Francine; Custódio Leite, Camila; Vianna Villela, Izabel; da Silva Machado, Miriana; Luiz Mendes Juchem, André; Roesch-Ely, Mariana; Neves Fernandes, Andreia; Salvador, Mirian; Antonio Pêgas Henriques, João

    2016-01-01

    The widespread use of titanium dioxide nanoparticles (TiO2-NP) in consumer products is the cause of its appearance in wastewater and effluents, reaching the aquatic environment. The evaluation of the biological impact of TiO2-NP and the need to understand its ecotoxicological impact to the aquatic ecosystem are of major concern. Bivalve mollusks may represent a target group for nanoparticle toxicity. Limnoperna fortunei (golden mussel), a freshwater bivalve organism that has been employed in biomonitoring environmental conditions. Comet assay, micronucleus test and oxidative damage to lipids and proteins were performed after the golden mussel was exposed to TiO2-NP (1, 5, 10 and 50μgmL(-1)). The results demonstrate that TiO2-NP can damage the DNA of haemocytes after 2h of exposure and the genotoxic activity significantly increased after 4h exposure to TiO2-NP, at all the TiO2-NP concentrations. TiO2-NP was ineffective in causing mutagenicity in the haemolymph cells of golden mussel. The increase in the lipid peroxidation levels and carbonyl proteins after the exposure to TiO2-NP indicates the induction of oxidative stress at 2h exposure with similar results to all TiO2-NP concentrations, but these effects did not occur at 4h exposure. These results demonstrated that, although TiO2-NP is not mutagenic to golden mussel, it does induce DNA damage and oxidative stress in these organisms.

  19. Improving sustainability in the remediation of contaminated soils by the use of compost and energy valorization by Paulownia fortunei.

    PubMed

    Madejón, Paula; Domínguez, María Teresa; Díaz, Manuel Jesús; Madejón, Engracia

    2016-01-01

    The plantation of fast growing trees in contaminated sites, in combination with the use of organic wastes, could partially solve a dual environmental problem: the disposal of these wastes and the improvement of soil quality in these degraded soils. This study evaluated the effects of two compost on the quantity and quality of Paulownia fortunei biomass and on syngas production by biomass gasification, produced by plants growing on trace elements contaminated soils. Compost increased biomass production to values similar to those produced in non-contaminated soils, due to the improvement in plant nutritional status. Moreover, biomass quality for gasification was increased by compost addition. Trace element accumulation in the biomass was relatively low and not related to biomass production or the gas quality obtained through gasification. Thus, P. fortunei plantations could pose an opportunity to improve the economic balance of the revegetation of contaminated soils, given that other commercial uses such as food or fodder crop production is not recommended in these soils.

  20. Transcriptome-Wide Profiling and Expression Analysis of Diploid and Autotetraploid Paulownia tomentosa × Paulownia fortunei under Drought Stress

    PubMed Central

    Xu, Enkai; Fan, Guoqiang; Niu, Suyan; Zhao, Zhenli; Deng, Minjie; Dong, Yanpeng

    2014-01-01

    Paulownia is a fast-growing deciduous hardwood species native to China, which has high ecological and economic value. In an earlier study, we reported ploidy-dependent differences in Paulownia drought tolerance by the microscopic observations of the leaves. Autotetraploid Paulownia has a higher resistance to drought stress than their diploid relatives. In order to obtain genetic information on molecular mechanisms responses of Paulownia plants to drought, Illumina/Solexa Genome sequencing platform was used to de novo assemble the transcriptomes of leaves from diploid and autotetraploid Paulownia tomentosa × Paulownia fortunei seedlings (PTF2 and PTF4 respectively) grown under control conditions and under drought stress and obtained 98,671 nonredundant unigenes. A comparative transcriptome analysis revealed that hundreds of unigenes were predicted to be involved mainly in ROS-scavenging system, amino acid and carbohydrate metabolism, plant hormone biosynthesis and signal transduction, while these unigenes exhibited differential transcript alteration of the two accessions. This study provides a comprehensive map of how P. tomentosa × P. fortunei responds to drought stress at physiological and molecular levels, which may help in understanding the mechanisms involve in water-deficit response and will be useful for further study of drought tolerance in woody plants. PMID:25405758

  1. Plant-Pathogen Interaction, Circadian Rhythm, and Hormone-Related Gene Expression Provide Indicators of Phytoplasma Infection in Paulownia fortunei

    PubMed Central

    Fan, Guoqiang; Dong, Yanpeng; Deng, Minjie; Zhao, Zhenli; Niu, Suyan; Xu, Enkai

    2014-01-01

    Phytoplasmas are mycoplasma-like pathogens of witches’ broom disease, and are responsible for serious yield losses of Paulownia trees worldwide. The molecular mechanisms of disease development in Paulownia are of considerable interest, but still poorly understood. Here, we have applied transcriptome sequencing technology and a de novo assembly approach to analyze gene expression profiles in Paulownia fortunei infected by phytoplasmas. Our previous researches suggested that methyl methane sulfonated (MMS) could reverse the effects of the infection. In this study, leaf samples from healthy, infected, and both infected and methyl methane sulfonate treated plants were analyzed. The results showed that the gene expression profile of P. fortunei underwent dramatic changes after Paulownia witches’ broom (PaWB) phytoplasma infection. Genes that encoded key enzymes in plant-pathogen interaction processes were significantly up-regulated in the PaWB-infected Paulownia. Genes involved in circadian rhythm and hormone-related genes were also altered in Paulownia after PaWB infection. However, after the PaWB-infected plants were treated with MMS, the expression profiles of these genes returned to the levels in the healthy controls. The data will help identify potential PaWB disease-resistance genes that could be targeted to inhibit the growth and reproduction of the pathogen and to increase plant resistance. PMID:25514414

  2. Transcriptome-wide profiling and expression analysis of diploid and autotetraploid Paulownia tomentosa × Paulownia fortunei under drought stress.

    PubMed

    Xu, Enkai; Fan, Guoqiang; Niu, Suyan; Zhao, Zhenli; Deng, Minjie; Dong, Yanpeng

    2014-01-01

    Paulownia is a fast-growing deciduous hardwood species native to China, which has high ecological and economic value. In an earlier study, we reported ploidy-dependent differences in Paulownia drought tolerance by the microscopic observations of the leaves. Autotetraploid Paulownia has a higher resistance to drought stress than their diploid relatives. In order to obtain genetic information on molecular mechanisms responses of Paulownia plants to drought, Illumina/Solexa Genome sequencing platform was used to de novo assemble the transcriptomes of leaves from diploid and autotetraploid Paulownia tomentosa × Paulownia fortunei seedlings (PTF2 and PTF4 respectively) grown under control conditions and under drought stress and obtained 98,671 nonredundant unigenes. A comparative transcriptome analysis revealed that hundreds of unigenes were predicted to be involved mainly in ROS-scavenging system, amino acid and carbohydrate metabolism, plant hormone biosynthesis and signal transduction, while these unigenes exhibited differential transcript alteration of the two accessions. This study provides a comprehensive map of how P. tomentosa × P. fortunei responds to drought stress at physiological and molecular levels, which may help in understanding the mechanisms involve in water-deficit response and will be useful for further study of drought tolerance in woody plants.

  3. Thermal tolerance of Limnoperna fortunei to gradual temperature increase and its applications for biofouling control in industrial and power plants.

    PubMed

    Perepelizin, Pablo V; Boltovskoy, Demetrio

    2011-07-01

    The acute upper lethal temperature (AULT) at different rates of increase was evaluated as a tool for the design of cheaper and environmentally friendlier control strategies for the invasive bivalve Limnoperna fortunei. Survivorship of 6 ± 2 mm and 20 ± 2 mm mussels acclimated to 12, 23 and 28 ° C and subjected to different heating rates (1 ° C per 5, 15 and 30 min) was estimated in the laboratory. The temperatures required to kill 50% (LT(50)) and 100% (SM(100)) of the mussels, and the mean death temperature (MDT) varied between 42.2 and 51 ° C over 54 experiments. Heating rates significantly (p < 0.001) affected LT(50), SM(100), and MDT. AULT was not affected by mussel size and acclimation temperatures. Limnoperna appears to be more resistant to high temperatures than Dreissena polymorpha, a mussel invasive in the USA and Europe. Lethal temperatures of L. fortunei are within the current thermal operational industrial capacities, suggesting that heat treatment is a viable alternative for controlling its fouling in utility systems.

  4. A phylogenetic backbone for Bivalvia: an RNA-seq approach.

    PubMed

    González, Vanessa L; Andrade, Sónia C S; Bieler, Rüdiger; Collins, Timothy M; Dunn, Casey W; Mikkelsen, Paula M; Taylor, John D; Giribet, Gonzalo

    2015-02-22

    Bivalves are an ancient and ubiquitous group of aquatic invertebrates with an estimated 10 000-20 000 living species. They are economically significant as a human food source, and ecologically important given their biomass and effects on communities. Their phylogenetic relationships have been studied for decades, and their unparalleled fossil record extends from the Cambrian to the Recent. Nevertheless, a robustly supported phylogeny of the deepest nodes, needed to fully exploit the bivalves as a model for testing macroevolutionary theories, is lacking. Here, we present the first phylogenomic approach for this important group of molluscs, including novel transcriptomic data for 31 bivalves obtained through an RNA-seq approach, and analyse these data with published genomes and transcriptomes of other bivalves plus outgroups. Our results provide a well-resolved, robust phylogenetic backbone for Bivalvia with all major lineages delineated, addressing long-standing questions about the monophyly of Protobranchia and Heterodonta, and resolving the position of particular groups such as Palaeoheterodonta, Archiheterodonta and Anomalodesmata. This now fully resolved backbone demonstrates that genomic approaches using hundreds of genes are feasible for resolving phylogenetic questions in bivalves and other animals.

  5. Algae consumption and nitrate removal in a raw water transport system by Limnoperna fortunei and its associated microorganisms.

    PubMed

    Zhang, Ruijian; Cui, Bin; Huang, Shaobin

    2014-12-01

    This laboratory-scale study investigated the effect of Limnoperna fortunei on chlorophyll a, phosphates, ammonia, and nitrates in a simulated raw water transport system, with a special focus on the isolation and identification of microbes in the biofilm attached to the shell surface. These microbes appear to be involved in the decreased concentration of nitrates observed in the water. The microbial communities in the raw water and on the surface of the mussel's shell were investigated through various methods, including a 16S rRNA phylogenetic analysis, which revealed significant diversity in terms of the structure and abundance of microbial species present. Two aerobic denitrifying bacteria (I-N38 and I-N45) were identified in shell biofilm that were capable of removing 95.5 and 100% of nitrates, respectively, within 24 hours.

  6. Bioassay-guided isolation and identification of antitermitic active compound from the leaf of Chinese cedar (Cryptomeria fortunei Hooibrenk).

    PubMed

    Xie, Yongjian; Huang, Qiuying; Lei, Chaoliang

    2013-01-01

    The persistent use of synthetic termiticides is at present of environmental concern and has resulted in the need to search for plant-derived compounds as an alternative for termite control. Antitermitic activity of Chinese cedar (Cryptomeria fortunei Hooibrenk) against Reticulitermes chinensis was demonstrated in laboratory tests. Bioactivity tests against the termite R. chinensis demonstrate that the lethal concentration (LC50) value of leaf essential oil is 2.80 mg/mL. Furthermore, α-terpineol, which was responsible for the antitermitic property and isolated from Chinese cedar that exhibited very strong antitermitic activity, was found to be significantly effective against R. chinensis with median LC50 values of 0.86 mg/mL. The findings suggested that the essential oil from Chinese cedar leaf and α-terpineol might be considered as a potent source for the production of effective, environmentally friendly and safe termiticides.

  7. Impact of multiple anthropogenic stressors on freshwater: how do glyphosate and the invasive mussel Limnoperna fortunei affect microbial communities and water quality?

    PubMed

    Pizarro, Haydée; Di Fiori, Eugenia; Sinistro, Rodrigo; Ramírez, Marina; Rodríguez, Patricia; Vinocur, Alicia; Cataldo, Daniel

    2016-01-01

    The study of the joint effect of multiple anthropogenic stressors is important because the emerging consequences are often unpredictable on the basis of knowledge of single effects. We explored the joint impact of glyphosate and the invasive golden mussel Limnoperna fortunei on freshwater phytoplankton, bacterioplankton and periphyton, and on the physical and chemical properties of the water. We manipulated both stressors simultaneously in a 25-day experiment using outdoor mesocosms; we assayed technical-grade glyphosate acid at four concentrations: 0, 1, 3 and 6 mg gly L(−1) under scenarios with and without mussels. The addition of the glyphosate significantly increased total phosphorus according to the concentration used; the high clearance rate of L. fortunei significantly decreased phytoplanktonic abundance leading to low values of turbidity. The mussel significantly stimulated the development of filamentous green algae (metaphyton). Interestingly, the combined effect revealed that L. fortunei accelerated the dissipation of glyphosate, which showed a 4-fold decrease in its half-life; this promoted the rapid bioavailability of glyphosate-derived phosphorus in the water. The interaction had a synergistic effect on soluble reactive phosphorus concentrations and was directly dependent on the concentration of glyphosate. A synergistic effect was also observed on bacterioplankton, water turbidity and metaphyton, thus inducing enhanced and rapid eutrophication. The ability of mussels to reduce glyphosate in water may be valued as positive, but our results allow us to predict that the invasion of Limnoperna fortunei in natural freshwater systems contaminated by glyphosate will accelerate the negative impact of the herbicide associated with eutrophication.

  8. Effect of glyphosate acid on biochemical markers of periphyton exposed in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei.

    PubMed

    Iummato, María Mercedes; Pizarro, Haydée; Cataldo, Daniel; Di Fiori, Eugenia; Dos Santos Afonso, María; Ríos de Molina, María Del Carmen; Juárez, Ángela Beatriz

    2017-04-11

    Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3 and 6 mg/L in outdoor mesocosms, in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight (AFDW), chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels and superoxide dismutase and catalase activities were determined at day 0, 1, 7, 14 and 26 of the experimental period. AFDW was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene/chlorophyll a ratio and enzyme activities and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in all these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results of the present study also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. This article is protected by copyright. All rights reserved.

  9. Differential impact of Limnoperna fortunei-herbicide interaction between Roundup Max® and glyphosate on freshwater microscopic communities.

    PubMed

    Gattás, F; Vinocur, A; Graziano, M; Dos Santos Afonso, M; Pizarro, H; Cataldo, D

    2016-09-01

    Multiple anthropogenic stressors act simultaneously on the environment, with consequences different from those caused by single-stressor exposure. We investigated how the combination of the invasive mussel Limnoperna fortunei and a widely applied herbicide, Roundup Max®, affected freshwater microscopic communities and water quality. Further, we compared these results with those induced by the combination of the mussel and technical-grade glyphosate. We carried out a 34-day experiment in outdoor mesocosms, applying the following six treatments: 6 mg L(-1) of technical-grade glyphosate (G), the equivalent concentration of glyphosate in Roundup Max® (R), 100 mussels (M), the combination of mussels and herbicide either in the technical-grade or formulated form (MG and MR, respectively), and control (C). Herbicides significantly increased total phosphorus in water; R and MR showed greater initial total nitrogen and ammonium. R increased picoplankton abundance and caused an eightfold increase in phytoplankton, with high turbidity values; G had a lower effect on these variables. Herbicide-mussel combination induced an accelerated dissipation of glyphosate in water (MG 6.36 ± 0.83 mg G g DW(-1) day(-1) and MR 5.16 ± 1.26 mg G g DW(-1) day(-1)). A synergistic effect on ammonium was observed in MR but not in MG. MR and MG had an antagonistic effect on phytoplankton, which showed a drastic reduction due to grazing, as revealed by M. We provide evidence of differential effects of Roundup Max® and technical-grade glyphosate over water quality and microscopic communities, and in combination with mussels. However, in the combination of mussels and herbicides, mussels seem to play a leading role. In the presence of L. fortunei, the effects of higher nutrient availability provided by herbicides addition were counteracted by the filtration activity of mussels, which released nutrients, grazed on picoplankton and phytoplankton, and boosted the development of other

  10. Biotransformation and antioxidant enzymes of Limnoperna fortunei detect site impact in watercourses of Córdoba, Argentina.

    PubMed

    Contardo-Jara, Valeska; Galanti, Lucas N; Amé, María V; Monferrán, Magdalena V; Wunderlin, Daniel A; Wiegand, Claudia

    2009-10-01

    The golden mussel Limnoperna fortunei was used as a biomonitor of environmental pollution in the Suquía River basin around Córdoba City (Argentina). The sampling sites along the river were chosen according to their increasing levels of pollutants (e.g. heavy metals) as well as biological oxygen demand (BOD) and chemical oxygen demand (COD). A water quality index (WQI) was constructed from the interaction of several normalized factors that affect the aquatic environment, such as the mentioned pollutants and physico-chemical characteristics of the sampling sites. Activity changes of biotransformation enzyme glutathione S-transferase (GST) and the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT), after exposure to pollutants, served as biomarkers. Membrane bound GST and antioxidant enzymes responded at the most polluted sampling site within 1 day showing increased activities lasting for 4 days. Further sampling was restricted due to no survival of the animals. Antioxidant enzymes GPx, GR and CAT were sensitive responding to the different pollution scenarios, showing good correlation to the chemical characterization.

  11. Discovery of Genes Related to Witches Broom Disease in Paulownia tomentosa × Paulownia fortunei by a De Novo Assembled Transcriptome

    PubMed Central

    Liu, Rongning; Dong, Yanpeng; Fan, Guoqiang; Zhao, Zhenli; Deng, Minjie; Cao, Xibing; Niu, Suyan

    2013-01-01

    In spite of its economic importance, very little molecular genetics and genomic research has been targeted at the family Paulownia spp. The little genetic information on this plant is a big obstacle to studying the mechanisms of its ability to resist Paulownia Witches’ Broom (PaWB) disease. Analysis of the Paulownia transcriptome and its expression profile data are essential to extending the genetic resources on this species, thus will greatly improves our studies on Paulownia. In the current study, we performed the de novo assembly of a transcriptome on P. tomentosa × P. fortunei using the short-read sequencing technology (Illumina). 203,664 unigenes with a mean length of 1,328 bp was obtained. Of these unigenes, 32,976 (30% of all unigenes) containing complete structures were chosen. Eukaryotic clusters of orthologous groups, gene orthology, and the Kyoto Encyclopedia of Genes and Genomes annotations were performed of these unigenes. Genes related to PaWB disease resistance were analyzed in detail. To our knowledge, this is the first study to elucidate the genetic makeup of Paulownia. This transcriptome provides a quick way to understanding Paulownia, increases the number of gene sequences available for further functional genomics studies and provides clues to the identification of potential PaWB disease resistance genes. This study has provided a comprehensive insight into gene expression profiles at different states, which facilitates the study of each gene’s roles in the developmental process and in PaWB disease resistance. PMID:24278262

  12. Discovery of genes related to witches broom disease in Paulownia tomentosa × Paulownia fortunei by a De Novo assembled transcriptome.

    PubMed

    Liu, Rongning; Dong, Yanpeng; Fan, Guoqiang; Zhao, Zhenli; Deng, Minjie; Cao, Xibing; Niu, Suyan

    2013-01-01

    In spite of its economic importance, very little molecular genetics and genomic research has been targeted at the family Paulownia spp. The little genetic information on this plant is a big obstacle to studying the mechanisms of its ability to resist Paulownia Witches' Broom (PaWB) disease. Analysis of the Paulownia transcriptome and its expression profile data are essential to extending the genetic resources on this species, thus will greatly improves our studies on Paulownia. In the current study, we performed the de novo assembly of a transcriptome on P. tomentosa × P. fortunei using the short-read sequencing technology (Illumina). 203,664 unigenes with a mean length of 1,328 bp was obtained. Of these unigenes, 32,976 (30% of all unigenes) containing complete structures were chosen. Eukaryotic clusters of orthologous groups, gene orthology, and the Kyoto Encyclopedia of Genes and Genomes annotations were performed of these unigenes. Genes related to PaWB disease resistance were analyzed in detail. To our knowledge, this is the first study to elucidate the genetic makeup of Paulownia. This transcriptome provides a quick way to understanding Paulownia, increases the number of gene sequences available for further functional genomics studies and provides clues to the identification of potential PaWB disease resistance genes. This study has provided a comprehensive insight into gene expression profiles at different states, which facilitates the study of each gene's roles in the developmental process and in PaWB disease resistance.

  13. Differential Gene Expression in Rhododendron fortunei Roots Colonized by an Ericoid Mycorrhizal Fungus and Increased Nitrogen Absorption and Plant Growth

    PubMed Central

    Wei, Xiangying; Chen, Jianjun; Zhang, Chunying; Pan, Dongming

    2016-01-01

    Ericoid mycorrhizal (ERM) fungi are specifically symbiotic with plants in the family Ericaceae. Little is known thus far about their symbiotic establishment and subsequent nitrogen (N) uptake at the molecular level. The present study devised a system for establishing a symbiotic relationship between Rhododendron fortunei Lindl. and an ERM fungus (Oidiodendron maius var. maius strain Om19), quantified seedling growth and N uptake, and compared transcriptome profiling between colonized and uncolonized roots using RNA-Seq. The Om19 colonization induced 16,892 genes that were differentially expressed in plant roots, of which 14,364 were upregulated and 2,528 were downregulated. These genes included those homologous to ATP-binding cassette transporters, calcium/calmodulin-dependent kinases, and symbiosis receptor-like kinases. N metabolism was particularly active in Om19-colonized roots, and 51 genes were upregulated, such as nitrate transporters, nitrate reductase, nitrite reductase, ammonium transporters, glutamine synthetase, and glutamate synthase. Transcriptome analysis also identified a series of genes involving endocytosis, Fc-gamma R-mediated phagocytosis, glycerophospholipid metabolism, and Gonadotropin-releasing hormone (GnRH) signal pathway that have not been reported previously. Their roles in the symbiosis require further investigation. The Om19 colonization significantly increased N uptake and seedling growth. Total N content and dry weight of colonized seedlings were 36.6 and 46.6% greater than control seedlings. This is the first transcriptome analysis of a species from the family Ericaceae colonized by an ERM fungus. The findings from this study will shed light on the mechanisms underlying symbiotic relationships of ericaceous species with ERM fungi and the symbiosis-resultant N uptake and plant growth. PMID:27826312

  14. First report of Perkinsus beihaiensis in wild clams Anomalocardia brasiliana (Bivalvia: Veneridae) in Brazil.

    PubMed

    Pinho Ferreira, Liana; Sabry, Rachel Costa; da Silva, Patrícia Mirella; Gesteira, Tereza Cristina Vasconcelos; de Souza Romão, Lidiane; Paz, Marcela Pinheiro; Feijó, Rubens Galdino; Neto, Maximiano Pinheiro Dantas; Maggioni, Rodrigo

    2015-03-01

    This is the first report of Perkinsus sp. (Bivalvia: Veneridae) infecting wild clams of the species Anomalocardia brasiliana in Brazil. The gill lamellae and rectum of 150 specimens of A. brasiliana collected in the Timonha river estuary (Ceará, Northeastern Brazil) in March 2012 were incubated in Ray's fluid thioglycollate medium (RFTM) for detection of Perkinsus sp. In RFTM, the prevalence of Perkinsus sp. was 14.7% (22/150) and the intensity of infection ranged from very light (1-10 cells across the slide) to light (12-100 cells). The presence of Perkinsus sp. was confirmed by PCR in seven (31.8%) out of 22 RFTM-positive specimens. DNA sequencing confirmed the presence of the genus Perkinsus and the phylogenetic analysis strongly indicated Perkinsus beihaiensis as the species responsible for the infection.

  15. Spermatozoa and spermatogenesis in the northern quahaug Mercenaria mercenaria (Mollusca, Bivalvia)

    NASA Astrophysics Data System (ADS)

    Ying, Xue-Ping; Yang, Wan-Xi; Dahms, Hans-U.; Lin, Zhihua; Chai, Xueliang

    2008-12-01

    We studied the ultrastructure of spermatogenesis and spermatozoa in the northern quahaug, the clam Mercenaria mercenaria. Spermatogenetic cells gradually elongate. Mitochondria gradually fuse and increase in size and electron density. During spermatid differentiation, proacrosomal vesicles migrate towards the presumptive anterior pole of the nucleus and eventually form the acrosome. The spermatozoon of M. mercenaria is of a primitive type. It is composed of head, mid-piece, and tail. The acrosome shows a subacrosomal space with a short conical contour. The slightly curved nucleus of the spermatozoon contains fine-grained dense chromatin. The middle piece consists of a centriolar complex which is surrounded by four mitochondria. The flagellum has a standard “9 + 2” microtubular structure. The ultrastructure of spermatozoa and spermatogenesis of M. mercenaria shares a number of features with other species of the family Veneridae. M. mercenaria may be a suitable model species for further investigations into the mechanisms of spermatogenesis in the Bivalvia.

  16. [Latin American malacology. Freshwater mollusks from Argentina].

    PubMed

    Rumi, Alejandra; Gregoric, Diego E Gutiérrez; Núñez, Verónica; Darrigran, Gustavo A

    2008-03-01

    . Species of sanitary interest are the propagators of: schistosomiasis -Biomphalaria peregrina, B. straminea y B. tenagophila, Planorbidae-, fasciolasis -Lymnaea viatrix and L. columnella, Lymnaeidae- and dermatitis -Chilina gibbosa and C. fluminea, Chilinidae. Invasive species are: Corbicula fluminea (Corbiculidae) and Limnoperna fortunei (Mytilidae). The construction of new areas for the protection and conservation of the high risk endemic species of freshwater molluscs is a priority. It is necessary to give special attention to the species of the patagonic mountain range and of the mesopotamic area of the Del Plata Basin.

  17. New records and a new species of bivalve (Mollusca: Bivalvia) from Miocene hydrocarbon seep deposits, North Island, New Zealand.

    PubMed

    Saether, Kristian P; Jingeng, Sha; Little, Crispin T S; Campbell, Kathleen A

    2016-08-18

    Fourteen bivalve taxa belonging to 11 families are present in at least 13 early to middle Miocene hydrocarbon seep deposits in the East Coast Basin, North Island, New Zealand. Among these are at least three new species, one of which, Semeloidea (s. l.) bexhavenensis sp. nov. (Lasaeidae), is described here. New distribution data are recorded for bivalve species in the families Limidae, Propeamussiidae, Malleidae and Solemyidae. Additional morphological details of Gigantidas coseli (Mytilidae) and Pratulum quinarium (Cardiidae) are provided based upon previously unrecorded internal shell features. Palaeoecological analysis indicates that bivalves utilized a broad range of modes of life and niches within the New Zealand Miocene seep environment, and no more than ca. 30% of these bivalve species were likely to have been obligate to seeps.

  18. Discovery of microRNAs and transcript targets related to witches' broom disease in Paulownia fortunei by high-throughput sequencing and degradome approach.

    PubMed

    Niu, Suyan; Fan, Guoqiang; Deng, Minjie; Zhao, Zhenli; Xu, Enkai; Cao, Lin

    2016-02-01

    Paulownia witches' broom (PaWB) caused by the phytoplasma is a devastating disease of Paulownia trees. It has caused heavy yield losses to Paulownia production worldwide. However, knowledge of the transcriptional and post-transcriptional regulation of gene expression by microRNAs (miRNAs), especially miRNAs responsive to PaWB disease stress, is still rudimentary. In this study, to identify miRNAs and their transcript targets that are responsive to PaWB disease stress, six sequencing libraries were constructed from healthy (PF), PaWB-infected (PFI), and PaWB-infected, 20 mg L(-1) methyl methane sulfonate-treated (PFI20) P. fortunei seedlings. As a result, 95 conserved miRNAs belonging to 18 miRNA families, as well as 122 potential novel miRNAs, were identified. Most of them were found to be a response to PaWB disease-induced stress, and the expression levels of these miRNAs were validated by quantitative real-time PCR analysis. The study simultaneously identified 109 target genes from the P. fortunei for 14 conserved miRNA families and 24 novel miRNAs by degradome sequencing. Furthermore, the functions of the miRNA targets were annotated based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. The results presented here provide the groundwork for further analysis of miRNAs and target genes responsive to the PaWB disease stress, and could be also useful for addressing new questions to better understand the mechanisms of plant infection by phytoplasma in the future.

  19. Structure and meiotic behaviour of B chromosomes in Sphaerium corneum/S. nucleus complex (Bivalvia: Sphaeriidae).

    PubMed

    Kořínková, Tereza; Král, Jiří

    2011-02-01

    Karyotypes of eight populations of Sphaerium corneum and two populations of S. nucleus (Bivalvia: Sphaeriidae) from central Europe were compared. The basic set of these hermaphroditic molluscs is formed by 30 biarmed autosomes and exhibits only slight interpopulational variation in morphology. These differences are not species-specific. One pair of nucleolar organiser regions was detected by silver staining. The prophase and metaphase of the first meiotic division is highly modified in both species. Pachytene is followed by a diffuse stage, characterized by decondensation of chromosomes and by enhanced metabolic activity. The diffuse stage has not been reported in bivalves so far. Bivalents of the following stages are achiasmatic both in the testicular and ovarian part of the gonad. The two species are further peculiar for occurrence of B chromosomes, which is a rare phenomenon in organisms with achiasmatic meiotic systems. The small metacentric B chromosomes exhibit intra- and interindividual variability in number, they show irregular meiotic pairing and segregation (formation of bivalents or univalents), and possess larger proportional amount of constitutive heterochromatin than the A chromosomes. Interestingly, the B chromosomes also undergo decondensation during the diffuse stage like A chromosomes which may indicate their transcriptional activity.

  20. Molecular phylogenetics in 2D: ITS2 rRNA evolution and sequence-structure barcode from Veneridae to Bivalvia.

    PubMed

    Salvi, Daniele; Mariottini, Paolo

    2012-11-01

    In this study, we analyzed the nuclear ITS2 rRNA primary sequence and secondary structure in Veneridae and comparatively with 20 Bivalvia taxa to test the phylogenetic resolution of this marker and its suitability for molecular diagnosis at different taxonomic levels. Maximum likelihood and Bayesian trees based on primary sequences were congruent with (profile-) neighbor-joining trees based on a combined model of sequence-structure evolution. ITS2 showed higher resolution below the subfamily level, providing a phylogenetic signal comparable to (mitochondrial/nuclear) gene fragments 2-5 times longer. Structural elements of the ITS2 folding, such as specific mismatch pairing and compensatory base changes, provided further support for the monophyly of some groups and for their phylogenetic relationships. Veneridae ITS2 folding is structured in six domains (DI-VI) and shows five striking sequence-structure features. Two of them, the Basal and Apical STEMs, are common to Bivalvia, while the presence of both the Branched STEM and the Y/R stretches occurs in five superfamilies of the two Heterodonta orders Myoida and Veneroida, thus questioning their reciprocal monophyly. Our results validated the ITS2 as a suitable marker for venerids phylogenetics and taxonomy, and underlined the significance of including secondary structure information for both applications at several systematic levels within bivalves.

  1. A Review of Marine Growth Protection System (MGPS) Options for the Royal Australian Navy

    DTIC Science & Technology

    2011-12-01

    DSTO-TR-2631 2.5.2 Protection or remediation  Mexel® 432 is a “ molecular level” filming agent of proprietary formulation which is marketed as...Salinity and temperature tolerances of the green and brown mussels, Perna viridis and Perna perna (Bivalvia: Mytilidae). Revista de Biologia Tropical

  2. The 5S rDNA gene family in mollusks: characterization of transcriptional regulatory regions, prediction of secondary structures, and long-term evolution, with special attention to Mytilidae mussels.

    PubMed

    Vizoso, Miguel; Vierna, Joaquín; González-Tizón, Ana M; Martínez-Lage, Andrés

    2011-01-01

    Several reports on the characterization of 5S ribosomal DNA (5S rDNA) in various animal groups have been published to date, but there is a lack of studies analyzing this gene family in a much broader context. Here, we have studied 5S rDNA variation in several molluskan species, including bivalves, gastropods, and cephalopods. The degree of conservation of transcriptional regulatory regions was analyzed in these lineages, revealing a conserved TATA-like box in the upstream region. The evolution of the 120 bp coding region (5S) was also studied, suggesting the occurrence of paralogue groups in razor clams, clams, and cockles. In addition, 5S rDNA sequences from 11 species and 7 genus of Mytilidae Rafinesque, 1815 mussels were sampled and studied in detail. Four different 5S rDNA types, based on the nontranscribed spacer region were identified. The phylogenetic analyses performed within each type showed a between-species gene clustering pattern, suggesting ancestral polymorphism. Moreover, some putative pseudogenized 5S copies were also identified. Our report, together with previous studies that found high degree of intragenomic divergence in bivalve species, suggests that birth-and-death evolution may be the main force driving the evolution of 5S rDNA in these animals, even at the genus level.

  3. Vesicomyinae (Bivalvia: Vesicomyidae) of the Kuril-Kamchatka Trench and adjacent abyssal regions

    NASA Astrophysics Data System (ADS)

    Krylova, Elena M.; Kamenev, Gennady M.; Vladychenskaya, Irina P.; Petrov, Nikolai B.

    2015-01-01

    Representatives of the subfamily Vesicomyinae (Bivalvia, Vesicomyidae) are tiny deep-sea molluscs distributed worldwide and reaching huge abundances of hundreds and thousands of specimens in trawl catches. During the German-Russian deep-sea expedition KuramBio (R/V Sonne, 2012) for the first time two vesicomyin species were collected from the abyssal plain adjacent to the Kuril-Kamchatka Trench from the depths of 4861-5787 m, Vesicomya pacifica (Smith, 1885) and "Vesicomya" filatovae sp.n. Two species of vesicomyins, V. sergeeviFilatova, 1971 and V. profundiFilatova, 1971, which were previously reported from the hadal of the Kuril-Kamchatka Trench, were not collected at the abyssal depth despite of the close geographical proximity of the sampling area to their distribution ranges. Altogether nine species of vesicomyins are recorded now from the West and Indo-West Pacific; data on distribution and morpho-anatomical characters of these species are provided. Taxonomic description of V. pacifica is revised including information on its soft part anatomy, new localities and COI sequences. For the first time for a vesicomyin bivalve molecular data is given for a species with an explicit morphological description and unambiguous taxonomic affiliation. Molecular analysis of 160 published COI sequences of vesicomyids and newly obtained molecular data on V. pacifica showed that V. pacifica and two undescribed vesicomyin species forming a monophyletic clade which exhibits sister relationships with the Pliocardiinae, the group of chemosymbiotic vesicomyids. "Vesicomya" filatovae sp.n. is provisionally assigned to the genus Vesicomya (s.l.) until additional morphological and molecular data are obtained. It differs from Vesicomya s.s. by a broader hinge margin with more radiating teeth and the presence of only one pair of demibranchs.

  4. Unionid bivalves (Mollusca: Bivalvia: Unionidae) of Presque Isle Bay, Erie, Pennsylvania

    USGS Publications Warehouse

    Masteller, E.C.; Maleski, K.R.; Schloesser, D.W.

    1993-01-01

    The purpose of this study was to determine species composition and relative abundance of unionid bivalves (Mollusca: Bivalvia: Unionidae) in Presque Isle Bay, Erie, Pennsylvania 1990-1992. This information was compared with data from the only other extensive survey of unionids in the bay conducted in 1909-1911 (Ortmann 1919) to assess changes over the 80 years preceding the present study. A total of 1,540 individuals representing 18 species were collected in 1990-1992. Five relatively common species (between 7 and 42% of total individuals), six uncommon species (2 and 6%), and seven rare species (<1%) were found. The rare species were Anodontoides ferussacianus, Lasmigona costata, Ligumia recta, Ptychobranchus fasciolaris, Quadrula pustulosa pustulosa, Strophitus undaulatus, and Truncilla donaciformis. Five of the species found in Presque Isle Bay (Leptodea fragilis, Ligumia nasuta, Potamilus alatus, Quadrula quadrula, and Truncilla donaciformis) are listed as critically imperiled and one species (Truncilla truncata) as extirpated in the State of Pennsylvania by the Western Pennsylvania Conservancy. Comparisons between unionid populations in 1909-1911 and 1990-1992 indicate few substantial changes occurred during the past 80 years. A total of 22 species were found; 21 in 1909-1911 and 18 in 1990-1992. Seventeen species were found in both studies, an additional four in 1909-1911 and one in 1990-1992. The relative abundance of 11 of the 17 species found in both studies remained stable (i.e., common or uncommon) over the past 80 years. Only four species listed as uncommon in 1909-1911 were listed as rare in 1990-1992. However, the invasion of the zebra mussel (Dreissena polymorpha) is considered a threat to the continued existence of the entire Unionidae fauna in Presque Isle Bay, a unique habitat of the Great Lakes.

  5. Comparative mitogenomic analysis reveals cryptic species: A case study in Mactridae (Mollusca: Bivalvia).

    PubMed

    Shen, Xin; Meng, Xue Ping; Chu, Ka Hou; Zhao, Na Na; Tian, Mei; Liang, Meng; Hao, Jue

    2014-12-01

    The Chinese surf clam Mactra chinensis Philippi, 1846 is a commercially important marine bivalve belonging to the family Mactridae (Mollusca: Bivalvia). In this study, the M. chinensis mitochondrial genomic features are analyzed. The genome has 34 genes on the same strand, lacking atp8 and both trnS (trnS1 and trnS2) as compared with the typical gene content of metazoan mitochondrial genomes. The A+T content of M. chinensis mitochondrial genome is 63.72%, which is slightly lower than that of M. veneriformis (67.59%) and Coelomactra antiquata (64.33% and 64.14% for the samples from Ri Zhao, Shandong Province, and Zhang Zhou, Fujian Province, China, respectively) in the same family. There are 22 NCRs in the M. chinensis mitochondrial genome, accounting for 12.91% of the genome length. The longest NCR (1,075bp in length) is located between trnT and trnQ. A TRS (127bp×8.15) accounts for 96.3% (1,035/1,075) of this NCR. The occurrence of TRS in NCR is shared by the two Mactra mitochondrial genomes, but is not found in the two Coelomactra mitochondrial genomes. A phylogenetic tree constructed based on 12 PCGs of 25 bivalve mitochondrial genomes shows that all seven genera (Mactra, Coelomactra, Paphia, Meretrix, Solen, Mytilus, and Crassostrea) constitute monophyletic groups with very high support values. Pairwise genetic distance analyses indicate that the genetic distance of C. antiquata from the two localities is 0.084, which is greater than values between congeneric species, such as those in Mactra, Mytilus, Meretrix, and Crassostrea. The results show that the C. antiquata from the two localities represent cryptic species.

  6. Factors driving changes in freshwater mussel (Bivalvia, Unionida) diversity and distribution in Peninsular Malaysia.

    PubMed

    Zieritz, Alexandra; Lopes-Lima, Manuel; Bogan, Arthur E; Sousa, Ronaldo; Walton, Samuel; Rahim, Khairul Adha A; Wilson, John-James; Ng, Pei-Yin; Froufe, Elsa; McGowan, Suzanne

    2016-11-15

    Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land.

  7. Molecular phylogeny of Pholadoidea Lamarck, 1809 supports a single origin for xylotrophy (wood feeding) and xylotrophic bacterial endosymbiosis in Bivalvia.

    PubMed

    Distel, Daniel L; Amin, Mehwish; Burgoyne, Adam; Linton, Eric; Mamangkey, Gustaf; Morrill, Wendy; Nove, John; Wood, Nicole; Yang, Joyce

    2011-11-01

    The ability to consume wood as food (xylotrophy) is unusual among animals. In terrestrial environments, termites and other xylotrophic insects are the principle wood consumers while in marine environments wood-boring bivalves fulfill this role. However, the evolutionary origin of wood feeding in bivalves has remained largely unexplored. Here we provide data indicating that xylotrophy has arisen just once in Bivalvia in a single wood-feeding bivalve lineage that subsequently diversified into distinct shallow- and deep-water branches, both of which have been broadly successful in colonizing the world's oceans. These data also suggest that the appearance of this remarkable life habit was approximately coincident with the acquisition of bacterial endosymbionts. Here we generate a robust phylogeny for xylotrophic bivalves and related species based on sequences of small and large subunit nuclear rRNA genes. We then trace the distribution among the modern taxa of morphological characters and character states associated with xylotrophy and xylotrepesis (wood-boring) and use a parsimony-based method to infer their ancestral states. Based on these ancestral state reconstructions we propose a set of plausible hypotheses describing the evolution of symbiotic xylotrophy in Bivalvia. Within this context, we reinterpret one of the most remarkable progressions in bivalve evolution, the transformation of the "typical" myoid body plan to create a unique lineage of worm-like, tube-forming, wood-feeding clams. The well-supported phylogeny presented here is inconsistent with most taxonomic treatments for xylotrophic bivalves, indicating that the bivalve family Pholadidae and the subfamilies Teredininae and Bankiinae of the family Teredinidae are non-monophyletic, and that the principle traits used for their taxonomic diagnosis are phylogenetically misleading.

  8. Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia)

    NASA Astrophysics Data System (ADS)

    Kapan, Sevinç; Kabasakal, Sinem

    2016-04-01

    Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia) Sevinç KAPAN, Sinem KABASAKAL, Çanakkale Onsekiz Mart University, Engineering Faculty, Geological Engineering Department sevinckapan_yesilyurt@hotmail.com In this study, paleontology and stratigraphy of Neogene and Quaternary units around south of the Dardanelles have been examined using Gastropoda and Bivalvia fauna. In the investigation area, the base of the sediments that belongs to Neogene, consist of the volcanics which are formed with basalts, andesites and tuff. Neogene begins unconformity with basal conglomerate which are formed with basalt and tuff gravels. The measurable thickness of the Neogene sediments is approximately 200meters in total. First fossiliferius level which consist of Lymnocardium (Euxinicardium) nobile Sabba has showed similarities with the Pontian (Late Miocene) fauna of the Eastern Paratethys. The existence of Melanopsis and Psidium species indicate that the basin has been brackish water feeding by fresh water in the Early Pliocene. Theodoxus fluviatilis (Linne), Theodoxus (Calvertia) aff. imbricata Brusina, Theodoxus (Calvertia) licherdopoli scriptus (Stefanescu), Viviparus mammatus (Stefanescu), Valvata (Valavata) sulekiana Brusina, Valvata (Cincinna) crusitensis Fontannes, Hydrobia cf grandis Cobalcescu, Hydrobia ventrosa Monfort, Melanopsis (Melanopsis) cf. bergeroni Stefanescu, , Melanopsis (Melanopsis) sandbergeri rumana Tournouer, Melanopsis (Canthidomus) hybostoma anili Taner, Melanopsis (Canthidomus) hybostoma amaradica Fontannes, Melanopsis (Canthidomus) lanceolata Neumayr, Amphimelania fossariformis (Tournouer), Melanoides tuberculata monolithica (Bukowski), Radix (Radix) peregra (Müller), Planorbarius thiollierei (Michaud), Potamida (Potamida) craiovensis craiovensis (Tournouer), Potamida (Potamida) berbestiensis (Fontannes), Unio pristinus davilai Porumbaru, Unio subexquisitus Jatzko, Anadonta zmaji

  9. Molecular phylogenetic analysis supports a Gondwanan origin of the Hyriidae (Mollusca: Bivalvia: Unionida) and the paraphyly of Australasian taxa.

    PubMed

    Graf, Daniel L; Jones, Hugh; Geneva, Anthony J; Pfeiffer, John M; Klunzinger, Michael W

    2015-04-01

    The freshwater mussel family Hyriidae (Mollusca: Bivalvia: Unionida) has a disjunct trans-Pacific distribution in Australasia and South America. Previous phylogenetic analyses have estimated the evolutionary relationships of the family and the major infra-familial taxa (Velesunioninae and Hyriinae: Hyridellini in Australia; Hyriinae: Hyriini, Castaliini, and Rhipidodontini in South America), but taxon and character sampling have been too incomplete to support a predictive classification or allow testing of biogeographical hypotheses. We sampled 30 freshwater mussel individuals representing the aforementioned hyriid taxa, as well as outgroup species representing the five other freshwater mussel families and their marine sister group (order Trigoniida). Our ingroup included representatives of all Australian genera. Phylogenetic relationships were estimated from three gene fragments (nuclear 28S, COI and 16S mtDNA) using maximum parsimony, maximum likelihood, and Bayesian inference, and we applied a Bayesian relaxed clock model calibrated with fossil dates to estimate node ages. Our analyses found good support for monophyly of the Hyriidae and the subfamilies and tribes, as well as the paraphyly of the Australasian taxa (Velesunioninae, (Hyridellini, (Rhipidodontini, (Castaliini, Hyriini)))). The Hyriidae was recovered as sister to a clade comprised of all other Recent freshwater mussel families. Our molecular date estimation supported Cretaceous origins of the major hyriid clades, pre-dating the Tertiary isolation of South America from Antarctica/Australia. We hypothesize that early diversification of the Hyriidae was driven by terrestrial barriers on Gondwana rather than marine barriers following disintegration of the super-continent.

  10. Presence and histopathological effects of the Parvatrema sp. (Digenea, Gymnophallidae) in the stout razor clam Tagelus plebeius (Bivalvia, Psammobiidae).

    PubMed

    da Silva, Patricia Mirella; Cremonte, Florencia; Sabry, Rachel Costa; Rosa, Rafael Diego; Cantelli, Liege; Barracco, Margherita Anna

    2009-09-01

    The stout razor clam Tagelus plebeius (Bivalvia, Psammobiidae) has a wide geographic distribution range, including the Brazilian coasts from the northeast (Alagoas) to the south (Santa Catarina). In March 2008, an episode of mass T. plebeius mortality (70%) occurred in an intertidal bed at The Pontal da Daniela, State of Santa Catarina, Brazil. We report here high prevalences (to 100%) of the trematode parasite Parvatrema sp. Cable, 1953 (Digenea, Gymnophallidae) infecting T. plebeius at high intensities. We describe the gymnophalid, echinostomatid and unidentified metacercariae parasites infecting the clam and the host reactions elicited by them. The use of special diagnostic techniques such as Ray's fluid thioglycollate medium (RFTM) and PCR assays to detect Perkinsus sp. pathogens, hemolymph cytology, and histopathological examinations did not show Perkinsus sp. infections, microcell infections, or neoplastic conditions. However, neither infections or pathology caused by trematode parasites; nor any other pathological condition could be uniquely correlated with the mortality event. A coincident flash flood might have contributed to cause the mortality episode. This is the first report of the Parvatrema sp. metacercariae larvae infecting the stout razor clam T. plebeius from Brazil.

  11. Thermal dependency of shell growth, microstructure, and stable isotopes in laboratory-reared Scapharca broughtonii (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    Nishida, Kozue; Suzuki, Atsushi; Isono, Ryosuke; Hayashi, Masahiro; Watanabe, Yusuke; Yamamoto, Yuzo; Irie, Takahiro; Nojiri, Yukihiro; Mori, Chiharu; Sato, Mizuho; Sato, Kei; Sasaki, Takenori

    2015-07-01

    We experimentally examined the growth, microstructure, and chemistry of shells of the bloody clam, Scapharca broughtonii (Mollusca: Bivalvia), reared at five temperatures (13, 17, 21, 25, and 29°C) with a constant pCO2 condition (˜450 μatm). In this species, the exterior side of the shell is characterized by a composite prismatic structure; on the interior side, it has a crossed lamellar structure on the interior surface. We previously found a negative correlation between temperature and the relative thickness of the composite prismatic structure in field-collected specimens. In the reared specimens, the relationship curve between temperature and the growth increment of the composite prismatic structure was humped shaped, with a maximum at 17°C, which was compatible with the results obtained in the field-collected specimens. In contrast, the thickness of the crossed lamellar structure was constant over the temperature range tested. These results suggest that the composite prismatic structure principally accounts for the thermal dependency of shell growth, and this inference was supported by the finding that shell growth rates were significantly correlated with the thickness of the composite prismatic structure. We also found a negative relationship between the rearing temperature and δ18O of the shell margin, in close quantitative agreement with previous reports. The findings presented here will contribute to the improved age determination of fossil and recent clams based on seasonal microstructural records.

  12. The influence of fish cage culture on δ13C and δ15N of filter-feeding Bivalvia (Mollusca).

    PubMed

    Benedito, E; Figueroa, L; Takeda, A M; Manetta, G I

    2013-11-01

    The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C) and nitrogen (δ15N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.

  13. Reproductive biology of blood cockle Anadara granosa (Bivalvia: Arcidae) in the northern region of the Strait of Malacca

    NASA Astrophysics Data System (ADS)

    Khalil, Munawar; Yasin, Zulfigar; Hwai, Tan Shau

    2017-03-01

    A study on the reproductive cycle of the blood cockle Anadara granosa (Bivalvia: Arcidae) was conducted at three different areas in the northern region of the Strait of Malacca. A total of 1,920 samples of adult A. granosa (38-71 mm length) were collected from June 2009 until September 2010. Qualitative techniques (gonadal microscopic fresh smear test and histology analysis) as well as quantitative techniques (analysis of condition index and gonadal index) were used to predict monthly gonadal development stages of A. granosa. The gonadal index of A. granosa from Banda Aceh (Indonesia) ( r = 0.469, P > 0.05) and Pulau Pinang (Malaysia) ( r = 0.123, P > 0.05) did not show any correlation to their condition index, whereas the gonadal index of A. granosa from Lhokseumawe (Indonesia) ( r = 0.609, P < 0.05) showed moderate positive correlation to the condition index. During the 16 month sampling period, four reproductive cycles were observed: each from three to six months. The process of releasing gametes is termed dribble spawning, and is the same in all populations. The principle component analysis (PCA) indicated that A. granosa reproduction was affected by interaction between internal physiological factors and indigenous environmental factors. In all sampling areas, phytoplankton density played a key role in the reproductive cycle in A. granosa. Information on the reproductive biology of this species is essential for species management and to improve the sustainability practices of the fisheries industry. These findings will provide basic information on the biology of the blood cockle A. granosa for stock management in the region.

  14. A new species of freshwater mussel (Bivalvia: Unionidae), Pleurobema athearni, from the Coosa River Drainage of Alabama, USA

    USGS Publications Warehouse

    Gangloff, M.M.; Williams, J.D.; Feminella, J.W.

    2006-01-01

    The Mobile Basin historically supported one of the most diverse freshwater mussel (Bivalvia: Unionidae) assemblages in North America. More than 65 species of mussels are known from the Basin, but it is difficult to determine how many species were present historically. The drainage's unique physical habitat was largely destroyed between the late 1800s and mid-1900s by impoundment and channel modifications of most of the larger rivers. Many species that were once common are now restricted to small headwater rivers and mid-sized tributaries. Recent Coosa River tributary surveys revealed a new, undescribed species of Pleurobema. This new species, Pleurobema athearni, is distinctive in outward appearance, shell morphometry and reproductive morphology, and can be distinguished from other Coosa River drainage unionids. Our analysis indicates that P. athearni is morphologically different from other similar taxa. It differs both in shell width/length and width/height ratios and thus provides a simple, quantitative means to differentiate this species from P. georgianum (Lea, 1841) Fusconaia barnesiana (Lea, 1838), and F. cerina (Conrad, 1838), which it superficially resembles and that also occur in the area. Our morphological diagnosis of this species is supported by recent molecular analyses that suggest this species is a Pleurobema and one closely related to other endemic Coosa River drainage unionids. The discovery of a new species of large, long-lived macroinvertebrate from a relatively well-sampled drainage in a populated region of the southeast United States underscores the need for more detailed surveys in isolated stretches of tributary streams. It should also serve as a reminder that almost 40 species of aquatic mollusks have been extirpated from the Mobile Basin before anything could be learned about their habitat or life history requirements. Copyright ?? 2006 Magnolia Press.

  15. Reproductive biology of blood cockle Anadara granosa (Bivalvia: Arcidae) in the northern region of the Strait of Malacca

    NASA Astrophysics Data System (ADS)

    Khalil, Munawar; Yasin, Zulfigar; Hwai, Tan Shau

    2017-02-01

    A study on the reproductive cycle of the blood cockle Anadara granosa (Bivalvia: Arcidae) was conducted at three different areas in the northern region of the Strait of Malacca. A total of 1,920 samples of adult A. granosa (38-71 mm length) were collected from June 2009 until September 2010. Qualitative techniques (gonadal microscopic fresh smear test and histology analysis) as well as quantitative techniques (analysis of condition index and gonadal index) were used to predict monthly gonadal development stages of A. granosa. The gonadal index of A. granosa from Banda Aceh (Indonesia) (r = 0.469, P > 0.05) and Pulau Pinang (Malaysia) (r = 0.123, P > 0.05) did not show any correlation to their condition index, whereas the gonadal index of A. granosa from Lhokseumawe (Indonesia) (r = 0.609, P < 0.05) showed moderate positive correlation to the condition index. During the 16 month sampling period, four reproductive cycles were observed: each from three to six months. The process of releasing gametes is termed dribble spawning, and is the same in all populations. The principle component analysis (PCA) indicated that A. granosa reproduction was affected by interaction between internal physiological factors and indigenous environmental factors. In all sampling areas, phytoplankton density played a key role in the reproductive cycle in A. granosa. Information on the reproductive biology of this species is essential for species management and to improve the sustainability practices of the fisheries industry. These findings will provide basic information on the biology of the blood cockle A. granosa for stock management in the region.

  16. Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

    PubMed Central

    Eisen, J A; Smith, S W; Cavanaugh, C M

    1992-01-01

    The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and between individual S. velum organisms suggested that one species of symbiont is dominant within and specific for this host species. Phylogenetic analysis of the 16S sequences of the symbionts indicates that they lie within the chemoautotrophic cluster of the gamma subdivision of the eubacterial group Proteobacteria. Images PMID:1577710

  17. Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

    PubMed

    Eisen, J A; Smith, S W; Cavanaugh, C M

    1992-05-01

    The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and between individual S. velum organisms suggested that one species of symbiont is dominant within and specific for this host species. Phylogenetic analysis of the 16S sequences of the symbionts indicates that they lie within the chemoautotrophic cluster of the gamma subdivision of the eubacterial group Proteobacteria.

  18. Phylogenetic and morphometric analyses reveal ecophenotypic plasticity in freshwater mussels Obovaria jacksoniana and Villosa arkansasensis (Bivalvia: Unionidae)

    PubMed Central

    Inoue, Kentaro; Hayes, David M; Harris, John L; Christian, Alan D

    2013-01-01

    Abstract Freshwater mollusk shell morphology exhibits clinal variation along a stream continuum that has been termed the Law of Stream Distribution. We analyzed phylogenetic relationships and morphological similarity of two freshwater mussels (Bivalvia: Unionidae), Obovaria jacksoniana and Villosa arkansasensis, throughout their ranges. The objectives were to investigate phylogenetic structure and evolutionary divergence of O. jacksoniana and V. arkansasensis and morphological similarity between the two species. Our analyses were the first explicit tests of phenotypic plasticity in shell morphologies using a combination of genetics and morphometrics. We conducted phylogenetic analyses of mitochondrial DNA (1416 bp; two genes) and morphometric analyses for 135 individuals of O. jacksoniana and V. arkansasensis from 12 streams. We examined correlations among genetic, morphological, and spatial distances using Mantel tests. Molecular phylogenetic analyses revealed a monophyletic relationship between O. jacksoniana and V. arkansasensis. Within this O. jacksoniana/V. arkansasensis complex, five distinct clades corresponding to drainage patterns showed high genetic divergence. Morphometric analysis revealed relative differences in shell morphologies between the two currently recognized species. We conclude that morphological differences between the two species are caused by ecophenotypic plasticity. A series of Mantel tests showed regional and local genetic isolation by distance. We observed clear positive correlations between morphological and geographic distances within a single drainage. We did not observe correlations between genetic and morphological distances. Phylogenetic analyses suggest O. jacksoniana and V. arkansasensis are synonomous and most closely related to a clade composed of O. retusa, O. subrotunda, and O. unicolor. Therefore, the synonomous O. jacksoniana and V. arkansasensis should be recognized as Obovaria arkansasensis (Lea 1862) n

  19. Updated mitochondrial phylogeny of Pteriomorph and Heterodont Bivalvia, including deep-sea chemosymbiotic Bathymodiolus mussels, vesicomyid clams and the thyasirid clam Conchocele cf. bisecta.

    PubMed

    Ozawa, Genki; Shimamura, Shigeru; Takaki, Yoshihiro; Yokobori, Shin-Ichi; Ohara, Yasuhiko; Takishita, Kiyotaka; Maruyama, Tadashi; Fujikura, Katsunori; Yoshida, Takao

    2017-02-01

    The mitochondrial genomes of bivalves have often been used for comparative genomics and for resolving phylogenetic relationships. More than 100 bivalve complete mitochondrial genomes have been sequenced to date. However, few mitochondrial genomes have been reported for deep-sea chemosymbiotic bivalves, which belong to the subclasses Pteriomorphia and Heterodonta. In the present study, we sequenced the mitochondrial genomes of eight deep-sea chemosymbiotic bivalve species: three species of Bathymodiolus mussels (B. japonicus, B. platifrons, and B. septemdierum), four species of vesicomyid clams (Abyssogena mariana, A. phaseoliformis, Isorropodon fossajaponicum, and Phreagena okutanii, all of which were formerly classified in the genus Calyptogena), and one species of thyasirid clam (Conchocele cf. bisecta). With a few exceptions, these mitochondrial genomes contained genes that are typical of metazoans: 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. The major non-coding region with a high A+T content of each genome, which contained tandem repeats and hairpins, was hypothesized to function as a control region. The phylogenetic trees of Pteriomorphia and Heterodonta were reconstructed based on the concatenated sequences of 14 shared genes. Bathymodiolus formed a monophyletic clade with asymbiotic Mytilidae mussels, the vesicomyid clams formed a monophyly that was sister to the Veneridae, and C. cf. bisecta branched basally in the Heterodonta. It is known that the gene orders of mitochondrial genomes vary among bivalves. To examine whether gene order variation exhibits phylogenetic signals, tree topologies based on the minimum number of gene rearrangements were reconstructed for two clades (superfamily Tellinoidea, which includes the Psammobiidae, Semelidae, Solecurtidae, and Tellinidae; and the clade comprising the Myidae, Mactridae, Arcticidae, Vesicomyidae, and Veneridae) with high statistical support in sequence-based phylogenies. The resulting tree

  20. Predicting the effects of climate change on population connectivity and genetic diversity of an imperiled freshwater mussel, Cumberlandia monodonta (Bivalvia: Margaritiferidae), in riverine systems.

    PubMed

    Inoue, Kentaro; Berg, David J

    2017-01-01

    In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream-dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under future climate scenarios. We then used forward-time simulations to project potential changes in genetic diversity and population connectivity based on these range shifts. ENM results under current conditions indicated long stretches of highly suitable habitat in rivers where C. monodonta persists; populations in the upper Mississippi River remain connected by suitable habitat that does not impede gene flow. Future climate scenarios projected northward and headwater-ward range contraction and drastic declines in habitat suitability for most extant populations throughout the Mississippi River Basin. Simulations indicated that climate change would greatly reduce genetic diversity and connectivity across populations. Results suggest that a single, large population of C. monodonta will become further fragmented into smaller populations, each of which will be isolated and begin to differentiate genetically. Because C. monodonta is a widely distributed species and purely aquatic, our

  1. The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae).

    PubMed

    Vierna, J; Jensen, K T; Martínez-Lage, A; González-Tizón, A M

    2011-08-01

    The linkage between 5S ribosomal DNA and other multigene families has been detected in many eukaryote lineages, but whether it provides any selective advantage remains unclear. In this work, we report the occurrence of linked units of 5S ribosomal DNA (5S rDNA) and U1 small nuclear DNA (U1 snDNA) in 10 razor shell species (Mollusca: Bivalvia: Pharidae) from four different genera. We obtained several clones containing partial or complete repeats of both multigene families in which both types of genes displayed the same orientation. We provide a comprehensive collection of razor shell 5S rDNA clones, both with linked and nonlinked organisation, and the first bivalve U1 snDNA sequences. We predicted the secondary structures and characterised the upstream and downstream conserved elements, including a region at -25 nucleotides from both 5S rDNA and U1 snDNA transcription start sites. The analysis of 5S rDNA showed that some nontranscribed spacers (NTSs) are more closely related to NTSs from other species (and genera) than to NTSs from the species they were retrieved from, suggesting birth-and-death evolution and ancestral polymorphism. Nucleotide conservation within the functional regions suggests the involvement of purifying selection, unequal crossing-overs and gene conversions. Taking into account this and other studies, we discuss the possible mechanisms by which both multigene families could have become linked in the Pharidae lineage. The reason why 5S rDNA is often found linked to other multigene families seems to be the result of stochastic processes within genomes in which its high copy number is determinant.

  2. Evidence for chemoautotrophic symbiosis in a Mediterranean cold seep clam (Bivalvia: Lucinidae): comparative sequence analysis of bacterial 16S rRNA, APS reductase and RubisCO genes.

    PubMed

    Duperron, Sébastien; Fiala-Médioni, Aline; Caprais, Jean-Claude; Olu, Karine; Sibuet, Myriam

    2007-01-01

    Symbioses between lucinid clams (Bivalvia: Lucinidae) and autotrophic sulphide-oxidizing bacteria have mainly been studied in shallow coastal species, and information regarding deep-sea species is scarce. Here we study the symbiosis of a clam, resembling Lucinoma kazani, which was recently collected in sediment cores from new cold-seep sites in the vicinity of the Nile deep-sea fan, eastern Mediterranean, at depths ranging from 507 to 1691 m. A dominant bacterial phylotype, related to the sulphide-oxidizing symbiont of Lucinoma aequizonata, was identified in gill tissue by comparative 16S rRNA gene sequence analysis. A second phylotype, related to spirochete sequences, was identified twice in a library of 94 clones. Comparative analyses of gene sequences encoding the APS reductase alpha subunit and ribulose-1,5-bisphosphate carboxylase oxygenase support the hypothesis that the dominant symbiont can perform sulphide oxidation and autotrophy. Transmission electron micrographs of gills confirmed the dominance of sulphide-oxidizing bacteria, which display typical vacuoles, and delta(13)C values measured in gill and foot tissue further support the hypothesis for a chemoautotrophic-sourced host carbon nutrition.

  3. Symbioses of methanotrophs and deep-sea mussels (Mytilidae: Bathymodiolinae).

    PubMed

    DeChaine, Eric G; Cavanaugh, Colleen M

    2006-01-01

    The symbioses between invertebrates and chemosynthetic bacteria allow both host and symbiont to colonize and thrive in otherwise inhospitable deep-sea habitats. Given the global distribution of the bathymodioline symbioses, this association is an excellent model for evaluating co-speciation and evolution of symbioses. Thus far, the methanotroph and chemoautotroph endosymbionts of mussels are tightly clustered within two independent clades of gamma Proteobacteria, respectively. Further physiological and genomic studies will elucidate the ecological and evolutionary roles that these bacterial clades play in the symbiosis and chemosynthetic community. Due to the overall abundance of the methanotrophic symbioses at hydrothermal vents and hydrocarbon seeps, they likely play a significant, but as of yet unquantified, role in the biogeochemical cycling of methane. With this in mind, the search for methanotrophic symbioses should not be restricted to these known deep-sea habitats, but rather should be expanded to include methane-rich coastal marine and freshwater environments inhabited by methanotrophs and bivalves. Our current understanding of the bathymodioline symbioses provides a strong foundation for future explorations into the origin, ecology, and evolution of methanotroph symbioses, which are now becoming possible through a combination of classical and advanced molecular techniques.

  4. Reproductive traits of the cold-seep symbiotic mussel Idas modiolaeformis: gametogenesis and larval biology.

    PubMed

    Marylène Gaudron, Sylvie; Demoyencourt, Emile; Duperron, Sébastien

    2012-02-01

    We describe the first reproductive features of a chemosynthetic mussel collected at cold seeps from the eastern Mediterranean Sea. Idas modiolaeformis (Bivalvia, Mytilidae) is a hermaphroditic species in which production of male and female gametes likely alternates, a feature regarded as an adaptation to patchy and ephemeral habitats. By using fluorescent in situ hybridization, we demonstrate that bacterial symbionts, while present within the gills, are absent within acini that enclose female gametes and male gametes. This supports the hypothesis of environmental acquisition of symbionts in chemosynthetic mytilids. Prodissoconch I (PI) is relatively small compared to prodissoconch II (PII), suggesting a planktotrophic larval stage. Diameters of the two larval shells are in the range of sizes reported for mytilids, with a PII size between that of the shallow Mytilus edulis and that of the cold-seep mussel "Bathymodiolus" childressi.

  5. Vesicomyidae (bivalvia): current taxonomy and distribution.

    PubMed

    Krylova, Elena M; Sahling, Heiko

    2010-04-01

    Vesicomyid bivalves are a consistent component of communities of sulphide-rich reducing environments distributed worldwide from 77 degrees N to 70 degrees S at depths from 100 to 9050 m. Up-to-now the taxonomy of the family has been uncertain. In this paper, the current state of vesicomyid taxonomy and distribution at the generic rank are considered. This survey is founded on a database including information both from literature sources and also unpublished data of the authors on all recent species of vesicomyids. We suggest that the Vesicomyidae is not a synonym of Kelliellidae, and is therefore a valid family name. We propose to divide the family Vesicomyidae into two subfamilies: Vesicomyinae and Pliocardiinae. The Vesicomyinae includes one genus, Vesicomya, which comprises small-sized bivalves characterized by non-reduced gut and the absence of subfilamental tissue in gills. Symbiosis with chemoautotrophic bacteria has, so far, not been proved for Vesicomya and the genus is not restricted to sulphide-rich reducing habitats. The subfamily Pliocardiinae currently contains about 15 genera with mostly medium or large body size, characterized by the presence of subfilamental tissue in the gills. The Pliocardiinae are highly specialized for sulphide-rich reducing environments, harbouring chemoautrophic bacteria in their gills. This is the first summary of the generic structure of the family Vesicomyidae that allow us to analyze the distribution of vesicomyids at the generic level. We recognize here five different distribution patterns that are related to the specific environmental demands. The general trends in the distribution patterns of the vesicomyids are an occurrence of the majority of genera in broad geographical ranges and the prevalence of near continental type of distribution.

  6. Vesicomyidae (Bivalvia): Current Taxonomy and Distribution

    PubMed Central

    Krylova, Elena M.; Sahling, Heiko

    2010-01-01

    Vesicomyid bivalves are a consistent component of communities of sulphide-rich reducing environments distributed worldwide from 77° N to 70°S at depths from 100 to 9050 m. Up-to-now the taxonomy of the family has been uncertain. In this paper, the current state of vesicomyid taxonomy and distribution at the generic rank are considered. This survey is founded on a database including information both from literature sources and also unpublished data of the authors on all recent species of vesicomyids. We suggest that the Vesicomyidae is not a synonym of Kelliellidae, and is therefore a valid family name. We propose to divide the family Vesicomyidae into two subfamilies: Vesicomyinae and Pliocardiinae. The Vesicomyinae includes one genus, Vesicomya, which comprises small-sized bivalves characterized by non-reduced gut and the absence of subfilamental tissue in gills. Symbiosis with chemoautotrophic bacteria has, so far, not been proved for Vesicomya and the genus is not restricted to sulphide-rich reducing habitats. The subfamily Pliocardiinae currently contains about 15 genera with mostly medium or large body size, characterized by the presence of subfilamental tissue in the gills. The Pliocardiinae are highly specialized for sulphide-rich reducing environments, harbouring chemoautrophic bacteria in their gills. This is the first summary of the generic structure of the family Vesicomyidae that allow us to analyze the distribution of vesicomyids at the generic level. We recognize here five different distribution patterns that are related to the specific environmental demands. The general trends in the distribution patterns of the vesicomyids are an occurrence of the majority of genera in broad geographical ranges and the prevalence of near continental type of distribution. PMID:20376362

  7. Relationship between bioenergetics responses and organic pollutants in the giant mussel, Choromytilus chorus (Mollusca: Mytilidae).

    PubMed

    Toro, Beatriz; Navarro, Jorge M; Palma-Fleming, Hernán

    2003-05-08

    Samples of Choromytilus chorus (giant mussel) were collected at three sampling stations exposed to different degrees of pollution along the south-central portion of the Chilean coast in spring 1998 and summer 1999. Measurements were carried out on clearance rate, absorption efficiency, and oxygen consumption of the mussels under controlled laboratory conditions, and related to analytical data on organic pollutants in their tissues. Scope for growth (SFG) was employed as a physiological index to evaluate stress produced by pollutants existing at each sampling site. Individuals from San Vicente bay (highly polluted) showed negative SFG values in spring (-4.6 J/h per g) and summer (-3.5 J/h per g). These results indicated severe stress related to the accumulation of toxic compounds in their tissues. Specimens from Corral bay (medium level of pollution) gave a SFG of 15.5 J/h per g in spring and 6.5 J/h per g in summer, while those from Yaldad bay (low pollution) presented an inverse situation was observed with SFG values of 6.2 J/h per g in spring which was lower than the summer value of 25.7 J/h per g. There was a significant negative correlation between the SFG of the different populations of C. chorus and the concentrations of organochlorines (OChs) and polynuclear aromatic hydrocarbons (PAHs) in their tissues.

  8. Sterols from Mytilidae show anti-aging and neuroprotective effects via anti-oxidative activity.

    PubMed

    Sun, Yujuan; Lin, Yanfei; Cao, Xueli; Xiang, Lan; Qi, Jianhua

    2014-11-25

    For screening anti-aging samples from marine natural products, K6001 yeast strain was employed as a bioassay system. The active mussel extract was separated to give an active sterol fraction (SF). SF was further purified, and four sterol compounds were obtained. Their structures were determined to be cholesterol (CHOL), brassicasterol, crinosterol, and 24-methylenecholesterol. All compounds showed similar anti-aging activity. To understand the action mechanism involved, anti-oxidative experiments, reactive oxygen species (ROS) assays, and malondialdehyde (MDA) tests were performed on the most abundant compound, CHOL. Results indicated that treatment with CHOL increases the survival rate of yeast under oxidative stress and decreases ROS and MDA levels. In addition, mutations of uth1, skn7, sod1, and sod2, which feature a K6001 background, were employed and the lifespans of the mutations were not affected by CHOL. These results demonstrate that CHOL exerts anti-aging effects via anti-oxidative stress. Based on the connection between neuroprotection and anti-aging, neuroprotective experiments were performed in PC12 cells. Paraquat was used to induce oxidative stress and the results showed that the CHOL and SF protect the PC12 cells from the injury induced by paraquat. In addition, these substance exhibited nerve growth factor (NGF) mimic activities again confirmed their neuroprotective function.

  9. Analysis of synonymous codon usage patterns in sixty-four different bivalve species

    PubMed Central

    De Moro, Gianluca; Venier, Paola; Pallavicini, Alberto

    2015-01-01

    Synonymous codon usage bias (CUB) is a defined as the non-random usage of codons encoding the same amino acid across different genomes. This phenomenon is common to all organisms and the real weight of the many factors involved in its shaping still remains to be fully determined. So far, relatively little attention has been put in the analysis of CUB in bivalve mollusks due to the limited genomic data available. Taking advantage of the massive sequence data generated from next generation sequencing projects, we explored codon preferences in 64 different species pertaining to the six major evolutionary lineages in Bivalvia. We detected remarkable differences across species, which are only partially dependent on phylogeny. While the intensity of CUB is mild in most organisms, a heterogeneous group of species (including Arcida and Mytilida, among the others) display higher bias and a strong preference for AT-ending codons. We show that the relative strength and direction of mutational bias, selection for translational efficiency and for translational accuracy contribute to the establishment of synonymous codon usage in bivalves. Although many aspects underlying bivalve CUB still remain obscure, we provide for the first time an overview of this phenomenon in this large, commercially and environmentally important, class of marine invertebrates. PMID:26713259

  10. Analysis of synonymous codon usage patterns in sixty-four different bivalve species.

    PubMed

    Gerdol, Marco; De Moro, Gianluca; Venier, Paola; Pallavicini, Alberto

    2015-01-01

    Synonymous codon usage bias (CUB) is a defined as the non-random usage of codons encoding the same amino acid across different genomes. This phenomenon is common to all organisms and the real weight of the many factors involved in its shaping still remains to be fully determined. So far, relatively little attention has been put in the analysis of CUB in bivalve mollusks due to the limited genomic data available. Taking advantage of the massive sequence data generated from next generation sequencing projects, we explored codon preferences in 64 different species pertaining to the six major evolutionary lineages in Bivalvia. We detected remarkable differences across species, which are only partially dependent on phylogeny. While the intensity of CUB is mild in most organisms, a heterogeneous group of species (including Arcida and Mytilida, among the others) display higher bias and a strong preference for AT-ending codons. We show that the relative strength and direction of mutational bias, selection for translational efficiency and for translational accuracy contribute to the establishment of synonymous codon usage in bivalves. Although many aspects underlying bivalve CUB still remain obscure, we provide for the first time an overview of this phenomenon in this large, commercially and environmentally important, class of marine invertebrates.

  11. Establishment of the green mussel, Perna viridis (Linnaeus 1758) (Mollusca: Mytilidae) on the West Coast of Florida

    USGS Publications Warehouse

    Benson, A.J.; Marelli, D.C.; Frischer, M.E.; Danforth, J.M.; Williams, J.D.

    2001-01-01

    In 1999, the green mussel, Perna viridis, was first observed in Tampa Bay, Florida. This was the first reported occurrence of this Indo-Pacific marine bivalve in North America. The mussels found in Tampa Bay were confirmed to be P. viridis based on both morphological and genetic characteristics. Since the initial discovery, surveys in Tampa Bay and on the west coast of Florida have documented the growth, recruitment, and range expansion of P. viridis. From November 1999 to July 2000, the mean shell length of a Tampa Bay population increased from 49.0 mm to 94.1 mm, an increase of 97%. Populations of P. viridis are successfully reproducing in Tampa Bay. Recruitment was observed on sampling plates in May and continued through July 2000. The full extent of mussel colonization is not clear, but mussels were found outside Tampa Bay in St. Petersburg, Florida, south to Venice. Based on these studies it is evident that P. viridis has successfully invaded Tampa Bay and the west coast of Florida. The long-term impact of P. viridis on native communities off the west coast of Florida cannot be predicted at this time.

  12. Carbonate-associated sulfate in lucinid (Bivalvia) shells

    NASA Astrophysics Data System (ADS)

    Peng, Y.; Bao, H.; Anderson, L.; Engel, A. S.

    2007-12-01

    Symbiosis is a fundamental driver of evolution, with examples ranging from mitochondria in eukaryotic cells to barnacle-whale commensalism. The association between sulfur-oxidizing (thiotrophic) bacteria and the lucinid bivalve clade is particularly intriguing because the inferred antiquity of the relationship (>400 m.y.) seems at odds with the relatively loose ecologic linkage of living members. Because only half of genus-level lucinid taxa are extant, and the δ13C of shell carbonate exhibits no systematic difference between symbiotic and non- symbiotic bivalves, a new morphologically-independent proxy to determine whether fossil taxa possessed thiotrophic endosymbionts is needed. The δ34S of carbonate-associated sulfate (CAS) in bivalve shells may hold promise because biogenic carbonate incorporates sulfate into its crystal structure during biomineralization. Incorporation of bacterially derived SO42- (with a more negative δ34S value due to its reduced sulfur origin) into the lucinid-shell crystal lattice would, therefore, impart a distinctly lower δ34SCAS value than that from seawater SO42-, and would be distinguishable from CAS values of co- occurring heterotrophic bivalves. We measured CAS contents, δ34SCAS and δ18OCAS values of 15 sets of lucinid and co-occurring infaunal and epifaunal heterotrophic bivalve shells collected from modern and Cenozoic shallow marine sites. The modern bivalve shells had variable CAS content, from 100 to 2600 ppm. Epifauna often had the highest concentrations relative to the other ecological groups. The δ34SCAS and δ18OCAS clustered at values corresponding to modern seawater sulfate, but with significant scatter. There was no systematic isotope- compositional difference among all bivalves in the same habitat, or among the same lucinid, infaunal, or epifaunal groups across different sites. The fossil bivalve shells tended to preserve lower CAS concentrations and the isotope compositions further deviated from seawater values. These data suggest that 1) pore-water sulfate in shallow sediments is highly heterogeneous in its concentration and isotope composition, probably due to active microbial sulfate reduction, bioturbation, and water-pumping by bivalves and other infaunal filter feeders; 2) CAS is derived from ambient porewater or pumped-in seawater for infauna or epifauna, as well as for lucinids; and 3) CAS concentration and isotope compositions are vulnerable to later diagenetic processes.

  13. Cytogenetics of the razor clam Solen marginatus (Mollusca: Bivalvia: Solenidae).

    PubMed

    Fernández-Tajes, J; González-Tizón, A; Martínez-Lage, A; Méndez, J

    2003-01-01

    The razor clam Solen marginatus has a diploid chromosome number of 38. The karyotype consists of one metacentric/submetacentric, three submetacentric/metacentric, five submetacentric, one submetacentric/subtelocentric, one subtelocentric/submetacentric, six subtelocentric and two telocentric chromosome pairs. Staining with chromomycin A3 revealed bright positive bands subcentromerically in the long arms of one medium-sized subtelocentric pair, while DAPI staining showed uniform fluorescence in all chromosomes of the complement. Fluorescence in situ hybridization using an 18S-5.8S-28S rDNA probe locates these loci at the subcentromeric region of one subtelocentric pair and at the subtelomeric region of another subtelocentric pair.

  14. Mitochondrial genome of the Peruvian scallop Argopecten purpuratus (Bivalvia: Pectinidae).

    PubMed

    Marín, Alan; Alfaro, Rubén; Fujimoto, Takafumi; Arai, Katsutoshi

    2015-01-01

    The mitochondrial genome of the Peruvian scallop Argopecten purpuratus was determined. The length of the mitochondrial coding region is 15,608 bp. A typical bivalve mitochondrial composition was detected with 12 protein-coding genes, 2 ribosomal RNA genes and 21 transfer RNA genes, with the absence of the atp8 gene. Fifty percent of the protein-coding genes use typical ATG start codon, whereas five genes utilize ATA as their start codon. Only one gene was found to utilize TTG as its start codon. The A. purpuratus mitogenome shows a significant similarity to that of A. irradians irradians, in length as well as in gene composition.

  15. The behaviour of giant clams (Bivalvia: Cardiidae: Tridacninae).

    PubMed

    Soo, Pamela; Todd, Peter A

    2014-01-01

    Giant clams, the largest living bivalves, live in close association with coral reefs throughout the Indo-Pacific. These iconic invertebrates perform numerous important ecological roles as well as serve as flagship species-drawing attention to the ongoing destruction of coral reefs and their associated biodiversity. To date, no review of giant clams has focussed on their behaviour, yet this component of their autecology is critical to their life history and hence conservation. Almost 100 articles published between 1865 and 2014 include behavioural observations, and these have been collated and synthesised into five sections: spawning, locomotion, feeding, anti-predation, and stress responses. Even though the exact cues for spawning in the wild have yet to be elucidated, giant clams appear to display diel and lunar periodicities in reproduction, and for some species, peak breeding seasons have been established. Perhaps surprisingly, giant clams have considerable mobility, ranging from swimming and gliding as larvae to crawling in juveniles and adults. Chemotaxis and geotaxis have been established, but giant clams are not phototactic. At least one species exhibits clumping behaviour, which may enhance physical stabilisation, facilitate reproduction, or provide protection from predators. Giant clams undergo several shifts in their mode of acquiring nutrition; starting with a lecithotrophic and planktotrophic diet as larvae, switching to pedal feeding after metamorphosis followed by the transition to a dual mode of filter feeding and phototrophy once symbiosis with zooxanthellae (Symbiodinium spp.) is established. Because of their shell weight and/or byssal attachment, adult giant clams are unable to escape rapidly from threats using locomotion. Instead, they exhibit a suite of visually mediated anti-predation behaviours that include sudden contraction of the mantle, valve adduction, and squirting of water. Knowledge on the behaviour of giant clams will benefit conservation and restocking efforts and help fine-tune mariculture techniques. Understanding the repertoire of giant clam behaviours will also facilitate the prediction of threshold levels for sustainable exploitation as well as recovery rates of depleted clam populations.

  16. Sublethal foot-predation on Donacidae (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    Salas, Carmen; Tirado, Cristina; Manjón-Cabeza, Maria Eugenia

    2001-08-01

    The incidence of foot nipping was studied on the Donax spp. of the littoral of Málaga (Southern Spain, 2875 specimens collected from February 1990 to January 1991) and of Ré island (French Atlantic coast, 262 specimens of Donax vittatus (Da Costa, 1778) collected in May 1996). In Málaga, Donax trunculus L., 1758 was the species most regularly nipped (18% of individuals), with peaks in summer (25% in August and 48% in September) and winter (34% in December). In Ré island, 27% of the specimens showed a nipped foot. Logistic regression shows that in D. trunculus length is the variable that most influences the probability of foot nipping, followed by weight and chlorophyll a. However, the difference in length between damaged and undamaged individuals was not significant (U-Mann-Whitney test). The size class frequency and the values of Ivlev's index show that the small size classes were avoided, while for the other size classes predation remained balanced throughout the year. Therefore, the avoidance of the small size classes makes length the most influential variable. The logistic regression indicated a coefficient B=-0.03 for weight. This implies a slightly negative influence on the probability of foot nipping. However, without the data of September, there is a positive correlation ( r=0.76, p<0.01) between the monthly percentages of predation and the flesh dry weight of a standard individual (25 mm long). The peak in September could be due to the recruitment peak of bivalves, which may have attracted more predators to the area, and/or to the recruitment of predators such as crabs to the swash zone. Logistic regression and test of comparison of percentages indicate that there was not any influence of the sex of an animal on the probability of foot nipping. Only in February was a significantly higher percentage ( p<0.05) of females nipped (44.44%) than the total of females in the sample (20.20%). The biomass (as flesh dry weight) of D. trunculus lost by foot nipping amounts to more than 20% in most of the size classes. There was an increase from the small sizes to the largest ones, in which it reaches 37%, with a positive correlation ( r=0.84; p<0.005) between size class and loss of biomass. Possible predators responsible for the foot nipping are crabs. Crab species usually found together with the donacids were Portumnus latipes (Pennant, 1777) Liocarcinus vernalis (Risso, 1816) and Atelecyclus undecimdentatus (Herbst, 1783). In aquarium experiments, they demonstrated an ability to nip the foot of clams. Portumnus latipes was the most active foot nipper, but left alive all the damaged clams. Therefore, we conclude that crabs are the most likely foot-nipping predators in the field.

  17. A complex picture of associations between two host mussels and symbiotic bacteria in the Northeast Atlantic

    NASA Astrophysics Data System (ADS)

    Rodrigues, Clara F.; Cunha, Marina R.; Génio, Luciana; Duperron, Sébastien

    2013-01-01

    Among chemosymbiotic metazoans found at deep-sea hydrothermal vents, cold seeps and organic falls, members of the mussel clade Bathymodiolinae (Bivalvia: Mytilidae) have evolved interactions with a higher diversity of bacterial lineages than other bivalve groups. Here, we characterized the bacteria associated with "Bathymodiolus" mauritanicus and Idas-like specimens from three sites in the Northeast Atlantic (two mud volcanoes in the Gulf of Cadiz and one seamount of the Gorringe Bank). Phylogenetic analysis of bacterial 16S rRNA-encoding gene sequences demonstrated that " B". mauritanicus has a dual symbiosis dominated by two phylotypes of methane-oxidising bacteria and a less abundant phylotype of a sulphur-oxidising bacterium. The latter was the dominant phylotype in a sympatric population of Idas-like mussels at the Darwin mud volcano. These results are the first report of a bacterial phylotype shared between two deep-sea mussels from divergent clades. This sulphur-oxidising bacterium was absent from Idas-like specimens from the other two sites (Gorringe Bank and Meknès mud volcano), in which bacterial clone libraries were dominated by other Gammaproteobacteria related to symbionts previously identified in Idas modiolaeformis from the Eastern Mediterranean. All Idas-like specimens studied herein are closely related and also related to I. modiolaeformis. However, they probably display different associations with bacteria, with the possible absence of both methane- and sulphur-oxidising symbionts at the Gorringe Bank. These results draw a very complex picture of associations between mussels and bacteria in the Northeast Atlantic, which could be highly variable depending on locale characteristics of the habitats.

  18. A complex picture of associations between two host mussels and symbiotic bacteria in the Northeast Atlantic.

    PubMed

    Rodrigues, Clara F; Cunha, Marina R; Génio, Luciana; Duperron, Sébastien

    2013-01-01

    Among chemosymbiotic metazoans found at deep-sea hydrothermal vents, cold seeps and organic falls, members of the mussel clade Bathymodiolinae (Bivalvia: Mytilidae) have evolved interactions with a higher diversity of bacterial lineages than other bivalve groups. Here, we characterized the bacteria associated with "Bathymodiolus" mauritanicus and Idas-like specimens from three sites in the Northeast Atlantic (two mud volcanoes in the Gulf of Cadiz and one seamount of the Gorringe Bank). Phylogenetic analysis of bacterial 16S rRNA-encoding gene sequences demonstrated that "B". mauritanicus has a dual symbiosis dominated by two phylotypes of methane-oxidising bacteria and a less abundant phylotype of a sulphur-oxidising bacterium. The latter was the dominant phylotype in a sympatric population of Idas-like mussels at the Darwin mud volcano. These results are the first report of a bacterial phylotype shared between two deep-sea mussels from divergent clades. This sulphur-oxidising bacterium was absent from Idas-like specimens from the other two sites (Gorringe Bank and Meknès mud volcano), in which bacterial clone libraries were dominated by other Gammaproteobacteria related to symbionts previously identified in Idas modiolaeformis from the Eastern Mediterranean. All Idas-like specimens studied herein are closely related and also related to I. modiolaeformis. However, they probably display different associations with bacteria, with the possible absence of both methane- and sulphur-oxidising symbionts at the Gorringe Bank. These results draw a very complex picture of associations between mussels and bacteria in the Northeast Atlantic, which could be highly variable depending on locale characteristics of the habitats.

  19. Dual symbiosis in a Bathymodiolus sp. mussel from a methane seep on the Gabon continental margin (Southeast Atlantic): 16S rRNA phylogeny and distribution of the symbionts in gills.

    PubMed

    Duperron, Sébastien; Nadalig, Thierry; Caprais, Jean-Claude; Sibuet, Myriam; Fiala-Médioni, Aline; Amann, Rudolf; Dubilier, Nicole

    2005-04-01

    Deep-sea mussels of the genus Bathymodiolus (Bivalvia: Mytilidae) harbor symbiotic bacteria in their gills and are among the dominant invertebrate species at cold seeps and hydrothermal vents. An undescribed Bathymodiolus species was collected at a depth of 3,150 m in a newly discovered cold seep area on the southeast Atlantic margin, close to the Zaire channel. Transmission electron microscopy, comparative 16S rRNA analysis, and fluorescence in situ hybridization indicated that this Bathymodiolus sp. lives in a dual symbiosis with sulfide- and methane-oxidizing bacteria. A distinct distribution pattern of the symbiotic bacteria in the gill epithelium was observed, with the thiotrophic symbiont dominating the apical region and the methanotrophic symbiont more abundant in the basal region of the bacteriocytes. No variations in this distribution pattern or in the relative abundances of the two symbionts were observed in mussels collected from three different mussel beds with methane concentrations ranging from 0.7 to 33.7 microM. The 16S rRNA sequence of the methanotrophic symbiont is most closely related to those of known methanotrophic symbionts from other bathymodiolid mussels. Surprisingly, the thiotrophic Bathymodiolus sp. 16S rRNA sequence does not fall into the monophyletic group of sequences from thiotrophic symbionts of all other Bathymodiolus hosts. While these mussel species all come from vents, this study describes the first thiotrophic sequence from a seep mussel and shows that it is most closely related (99% sequence identity) to an environmental clone sequence obtained from a hydrothermal plume near Japan.

  20. Doubly uniparental inheritance (DUI) of mitochondrial DNA in Donax trunculus (Bivalvia: Donacidae) and the problem of its sporadic detection in Bivalvia.

    PubMed

    Theologidis, Ioannis; Fodelianakis, Stilianos; Gaspar, Miguel B; Zouros, Eleftherios

    2008-04-01

    Mitochondrial DNA is transmitted maternally in metazoan species. This rule does not hold in several species of bivalves that have two mtDNA types, one that is transmitted maternally and the other paternally. This system of mitochondrial DNA transmission is known as doubly uniparental inheritance (DUI). Here we present evidence of DUI in the clam Donax trunculus making Donacidae the sixth bivalve family in which the phenomenon has been found. In addition, we present the taxonomic affiliation of all species in which DUI is currently known to occur and construct a phylogeny of the maternal and paternal genomes of these species. We use this information to address the question of a single or multiple origins of DUI and to discuss whether failed attempts to demonstrate the presence of DUI in several bivalve species might be due to problems of detection or to genuine absence of the phenomenon.

  1. [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.

  2. [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.

  3. Complete mitochondrial genome of the Olympia oyster Ostrea lurida (Bivalvia, Ostreidae).

    PubMed

    Xiao, Shu; Wu, Xiangyun; Li, Lu; Yu, Ziniu

    2015-06-01

    The complete mitochondrial (mt) genome of the Olympia oyster Ostrea lurida (16,344 bp), an economically important bivalve, was newly sequenced and annotated. Ostrea lurida is the largest reported Ostrea oyster mt genomes to date and has a comparatively highest overall A + T content (65%) among the available genomes of marine oysters. High levels of variability of nad2 and nad6 genes and that of major non-coding region (MNR) indicate their potential value as useful molecular markers for population and conservation genetic studies in the future. Phylogenetic analyses based on concatenated nucleotide sequences from all 13 PCGs and 2 rRNA genes show that the European flat oyster Ostrea edulis is sister to the Asian slipper oyster Ostrea denselamellosa, while O. lurida is put at the most basal position of the clade, and indicate that Ostrea are closer to Saccostrea than Crassostrea, although gene arrangement shows a closer relationship between Ostrea and Crassostrea. The observations of the evolutionary pattern of start codon usage among the three congeneric oysters indicate that variation in start codon usage is species-correlated rather than gene-correlated, and to some extent, bears useful phylogenetic information.

  4. Comparative Large-Scale Mitogenomics Evidences Clade-Specific Evolutionary Trends in Mitochondrial DNAs of Bivalvia

    PubMed Central

    Plazzi, Federico; Puccio, Guglielmo; Passamonti, Marco

    2016-01-01

    Despite the figure of complete bivalve mitochondrial genomes keeps growing, an assessment of the general features of these genomes in a phylogenetic framework is still lacking, despite the fact that bivalve mitochondrial genomes are unusual under different aspects. In this work, we constructed a dataset of one hundred mitochondrial genomes of bivalves to perform the first systematic comparative mitogenomic analysis, developing a phylogenetic background to scaffold the evolutionary history of the class' mitochondrial genomes. Highly conserved domains were identified in all protein coding genes; however, four genes (namely, atp6, nad2, nad4L, and nad6) were found to be very divergent for many respects, notwithstanding the overall purifying selection working on those genomes. Moreover, the atp8 gene was newly annotated in 20 mitochondrial genomes, where it was previously declared as lacking or only signaled. Supernumerary mitochondrial proteins were compared, but it was possible to find homologies only among strictly related species. The rearrangement rate on the molecule is too high to be used as a phylogenetic marker, but here we demonstrate for the first time in mollusks that there is correlation between rearrangement rates and evolutionary rates. We also developed a new index (HERMES) to estimate the amount of mitochondrial evolution. Many genomic features are phylogenetically congruent and this allowed us to highlight three main phases in bivalve history: the origin, the branching of palaeoheterodonts, and the second radiation leading to the present-day biodiversity. PMID:27503296

  5. Muscle and neuronal differentiation in primary cell culture of larval Mytilus trossulus (Mollusca: Bivalvia).

    PubMed

    Odintsova, Nelly A; Dyachuk, Vyacheslav A; Nezlin, Leonid P

    2010-03-01

    Molluscan in vitro technology allows the study of the differentiation of isolated cells undergoing experimental manipulations. We have used the immunofluorescence technique and laser scanning microscopy to investigate the organization of muscle proteins (actin, myosin, paramyosin, and twitchin) and the localization of neurotransmitters (serotonin and FMRFamide) in cultured mussel larval cells. Differentiation into muscle and neuron-like cells occurs during the cultivation of mussel cells from premyogenic and prenervous larval stages. Muscle proteins are colocalized in contractile cells through all stages of cultivation. The cultivation of mussel cells on various substrates and the application of integrin receptor blockers suggest that an integrin-dependent mechanism is involved in cell adhesion and differentiation. Dissociated mussel cells aggregate and become self-organized in culture. After 20 days of cultivation, they form colonies in which serotonin- and FMRFamide-immunoreactive cells are located centrally, whereas muscle cells form a contractile network at the periphery. The pattern of thick and thin filaments in cultivated mussel cells changes according to the scenario of muscle arrangement in vivo: initially, a striated pattern of muscle filaments forms but is then replaced by a smooth muscle pattern with a diffuse distribution of muscle proteins, typical of muscles of adult molluscs. Myogenesis in molluscs thus seems to be a highly dynamic and potentially variable process. Such a "flexible" developmental program can be regarded as a prerequisite for the evolution of the wide variety of striated and smooth muscles in larval and adult molluscs.

  6. Misidentification of freshwater mussel species (Bivalvia:Unionidae): contributing factors, management implications, and potential solutions

    USGS Publications Warehouse

    Shea, Colin P.; Peterson, James T.; Wisniewski, Jason M.; Johnson, Nathan A.

    2011-01-01

    Surveys of freshwater mussel populations are used frequently to inform conservation decisions by providing information about the status and distribution of species. It is generally accepted that not all mussels or species are collected during surveys, and incomplete detection of individuals and species can bias data and can affect inferences. However, considerably less attention has been given to the potential effects of species misidentification. To evaluate the prevalence of and potential reasons for species misidentification, we conducted a laboratory-based identification exercise and quantified the relationships between mussel species characteristics, observer experience, and misidentification rate. We estimated that misidentification was fairly common, with rates averaging 27% across all species and ranging from 0 to 56%, and was related to mussel shell characteristics and observer experience. Most notably, species with shell texturing were 6.09× less likely than smooth-shelled species to be misidentified. Misidentification rates declined with observer experience, but for many species the risk of misidentification averaged >10% even for observers with moderate levels of experience (5–6 y). In addition, misidentification rates among observers showed substantial variability after controlling for experience. Our results suggest that species misidentification may be common in field surveys of freshwater mussels and could potentially bias estimates of population status and trends. Misidentification rates possibly could be reduced through use of regional workshops, testing and certification programs, and the availability of archived specimens and tissue samples in museum collections.

  7. Life history and propagation of the endangered fanshell pearlymussel, Cyprogenia stegaria Rafinesque (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Jones, J.W.; Neves, R.J.

    2002-01-01

    Aspects of the reproduction, age, growth, fish hosts, and culture of juveniles were determined for the endangered fanshell pearlymussel, Cyprogenia stegaria Rafinesque, 1820, in the Clinch River, Tennessee. Glochidia of C. stegaria are contained in red, worm-like conglutinates that resemble oligochaetes. Conglutinates are 20 to 80 mm long and are released through the excurrent aperture. Estimated fecundity was 22,357 to 63,459 glochidia/mussel. Eighty-four valves of C. stegaria were thin-sectioned for aging; ages ranged from 6 to 26 y. Of 16 fish species tested, 9 hosts were identified through induced infestations of glochidia: mottled sculpin (Cottus bairdi), banded sculpin (Cottus carolinae), greenside darter (Etheostoma blennioides), snubnose darter (Etheostoma simoterurn), banded darter (Etheostoma zonale), tangerine darter (Percina aurantiaca), blotchside logperch (Percina burtoni), logperch (Percina caprodes), and Roanoke darter (Percina roanoka). Newly metamorphosed juveniles were cultured in recirculating and nonrecirculating aquaculture systems within dishes containing sediments of 300 to 500 ??m diameter (sand) or <105 ??m diameter (silt), and fed either the green algae Neochloris oleoabundans or Scenedesrnus quadricauda daily. Growth and survival of juvenile mussels were highest in the nonrecirculating aquaculture system, with a mean survival of 72% after 2 wk and 38% after 4 wk.

  8. Chlorine toxicity to early life stages of freshwater mussels (Bivalvia: Unionidae).

    PubMed

    Valenti, Theodore W; Cherry, Donald S; Currie, Rebecca J; Neves, Richard J; Jones, Jess W; Mair, Rachel; Kane, Cynthia M

    2006-09-01

    Chlorine (Cl) is a highly toxic, widely used halogen disinfectant that is present in point-source pollution discharges from wastewater treatment plants and industrial facilities. The U.S. Environmental Protection Agency freshwater criteria for Cl are 19 microg total residual Cl (TRC)/L as a maximum 1-h average concentration and 11 microg TRC/L as a maximum 4-d average; however, toxicological data for unionids were not used in these calculations. To address this void in the data, we conducted acute tests with glochidia from several species and 21-d bioassays with three-month-old Epioblasma capsaeformis and three-, six-, and 12-month-old Villosa iris juveniles. The 24-h lethal concentration 50 values for glochidia were between 70 and 220 [Lg TRC/L, which are 2.5 to 37 times higher than those reported in other studies for cladocerans. Significant declines in growth and survivorship were observed in the 21-d test with E. capsaeformis at 20 microg TRC/L. Lowest-observed-adverse-effects concentrations in bioassays with juvenile V. iris were higher (30-60 microg TRC/L) but showed a significant trend of declining toxicity with increased age. Although endpoints were above water quality criteria, the long life spans of unionids and potential implications of chronic exposure to endangered juvenile mussels still warrant concern.

  9. Direct evidence for maternal inheritance of bacterial symbionts in small deep-sea clams (Bivalvia: Vesicomyidae).

    PubMed

    Szafranski, Kamil M; Gaudron, Sylvie M; Duperron, Sébastien

    2014-05-01

    Bacterial symbiont transmission is a key step in the renewal of the symbiotic interaction at each host generation, and different modes of transmission can be distinguished. Vesicomyidae are chemosynthetic bivalves from reducing habitats that rely on symbiosis with sulfur-oxidizing bacteria, in which two studies suggesting vertical transmission of symbionts have been published, both limited by the imaging techniques used. Using fluorescence in situ hybridization and transmission electron microscopy, we demonstrate that bacterial symbionts of Isorropodon bigoti, a gonochoristic Vesicomyidae from the Guiness cold seep site, occur intracellularly within female gametes at all stages of gametogenesis from germ cells to mature oocytes and in early postlarval stage. Symbionts are completely absent from the male gonad and gametes. This study confirms the transovarial transmission of symbionts in Vesicomyidae and extends it to the smaller species for which no data were previously available.

  10. [Does the comparator method has a future in diagnosing large bivalves (Bivalvia: Unionida)?].

    PubMed

    Bogatov, V V

    2014-01-01

    It is shown that the contours of the frontal sections of valves in shells of different size of the same species run through different parts of the valve. A new modification of the comparator method is proposed, which allows studying the shape of the maximum convex contour of the cross-section of the shell.

  11. Pattern and process of diversification in an ecologically diverse epifaunal bivalve group Pterioidea (Pteriomorphia, Bivalvia).

    PubMed

    Tsubaki, Remi; Kameda, Yuichi; Kato, Makoto

    2011-01-01

    The pterioid bivalves (superfamily Pterioidea) are epifaunal filter feeders that attach to various substrata, including rocks, corals, gorgonians, and sponges. An intriguing question is how different substratum types have affected the diversification of pterioid bivalves. To elucidate the evolutionary pathway of Pterioidea, we conducted a phylogenetic analysis of 49 individuals belonging to 18 pterioid and 5 outgroup species using 18S and 28S ribosomal RNA genes. The results supported the monophyly of superfamily Pterioidea and recovered three major clades within Pterioidea: Malleus, Pteria and Electroma (Pterelectroma) zebra and the rest. This result contradicts the current circumscription of the pterioid families, Pteriidae, Malleidae, and Isognomonidae, and suggests that hinge morphology, which has long been used as a diagnostic character, does not reflect phylogenetic relationships. The monophyly of most genera, however, was confirmed. Mapping substrata types on the phylogenetic tree indicated that the ancestors of pterioid bivalves were epifaunal on rocks, and that epizoic life on sessile cnidarians had a single origin. Although we could not ascertain whether endozoic life in sponges evolved once or twice, our results suggest that colonization of biotic substrata resulted in diversification and morphological and ecological adaptation to epi-/endozoic life. We estimated that the genus Pteria has diversified since the late Cretaceous in response to gorgonian diversification. These results emphasize the importance of substratum shifts in speciation and diversification of pterioid bivalves.

  12. Mitochondrial genome of the cockscomb pearl mussel Cristaria plicata (Bivalvia, Unionoida, Unionidae).

    PubMed

    Lee, Jin Hee; Choi, Eun Hwa; Kim, Sang Ki; Ryu, Shi Hyun; Hwang, Ui Wook

    2012-02-01

    The complete mitochondrial genome sequence of the cockscomb pearl mussel Cristaria plicata, which is an endangered species in South Korea, was sequenced. The circle genome (15,708 bp in size) consists of 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. There were 26 noncoding regions (NCs) found throughout the mitogenome of C. plicata, ranging in size from 2 to 327 bp, and the two largest NC regions, NC286 and NC326, were found between ND5 and tRNA(Gln) (286 bp) and between tRNA(Glu) and ND2 (326 bp), respectively. The 13 mitochondrial protein-coding genes of a female individual of C. plicata collected from Korea (15,708 bp) were compared to those of the Chinese individual (15,712 bp) published before. The result showed that ND3 is the most conserved with 100% nucleotide similarity, and each of the other protein-coding genes has ca. 99%, respectively. The two largest NCs among 26 NCs have totally 98% nucleotide similarity between Korean and Chinese ones.

  13. The complete maternal mitochondrial genome of rare Chinese freshwater mussel Lepidodesma languilati (Bivalvia: Unionidae: Unioninae).

    PubMed

    Zhou, Chun-Hua; Ouyang, Shan; Wu, Xiao-Ping; Ding, Mei-Huang

    2016-11-01

    Lepidodesma languilati is considered threatened because of the influence of human activities in China. The complete F-type mitochondrial genome of L. languilati was determined in this study (GenBank accession no. KT381195). It is a 15 754-bp-long circular molecule that consists of 37 genes that are typically found in other invertebrates. The overall base composition of the entire sequence is as follows: A (39.1%), T (25.7%), C (23.4%), and G (11.8%). Except for cox1 (TTG), cob (ATT), nad1 (ATT), nad6 (ATA), nad4 (TTG), and atp8 (GTG), 7 of the 13 protein-coding genes initiate with orthodox ATG start codon. All the 13 protein-coding genes have complete termination codon TAA or TAG. Phylogenetic tree indicates that L. languilati belongs to Unioninae. The newly sequenced complete mitogenome can provide basic data for comparative studies on mitochondrial genomes of Unionidae. It could also lay the important theoretical foundation for phylogenetics, population genetics, germplasm resources protection, sustainable, and reasonable utilization.

  14. Host specificity and metamorphosis of the glochidium of the freshwater mussel Unio tumidiformis (Bivalvia: Unionidae).

    PubMed

    Reis, Joaquim; Collares-Pereira, Maria João; Araujo, Rafael

    2014-02-01

    The glochidium larvae of freshwater mussels of the family Unionidae need to find suitable hosts to attach themselves and metamorphose into free-living juveniles. The specificity of the host-parasite relationship was investigated for the Iberian Unio tumidiformis Castro, 1885 by means of experimental infections and also by analyzing naturally infected fish. The process of encapsulation of glochidia was studied using scanning electron microscopy. Unio tumidiformis has proven to be an unusual host-specific unionid mussel, apparently parasitizing only fish of the genus Squalius Bonaparte, 1837. Successful encapsulation or complete metamorphosis was observed in five fish taxa: S. aradensis (Coelho, Bogutskaya, Rodrigues et Collares-Pereira), S. caroliterti (Doadrio), S. pyrenaicus (Günther), S. torgalensis (Coelho, Bogutskaya, Rodrigues et Collares-Pereira) and S. alburnoides (Steindachner) complex (only for the nuclear hybrids with at least one copy of the S. pyrenaicus genome). Complete metamorphose was achieved in 6 to 14 days at mean temperatures ranging from 21.8 to 26.1 degrees C. The current study provides support for cell migration being the main force of cyst formation and shows the influence of potential host's genome in response to the infection process to determine the success of the metamorphosis.

  15. Byssogenesis in the juvenile pink heelsplitter mussel, Potamilus alatus (Bivalvia: Unionidae).

    PubMed

    Wen, Hai B; Hua, Dan; Ma, Xue Y; Jin, Wu; Zhuang, Yan B; Gu, Ruo B; Yuan, Xin H; Du, Xin W; Xu, Pao

    2015-11-01

    The North American pink heelsplitter (Potamilus alatus) differs from most freshwater mussels in China by the ability to secrete an ephemeral byssus during its juvenile stage. In the present study, light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to investigate this ephemeral byssal structure, and amino acid composition was analyzed and compared with that of other species. The results revealed that the byssus consists of a long byssal thread and a few adhesive plaques which are randomly set up along the thread and assembled by petioles. There is a thin but distinctive cuticle with a continuous homogeneous matrix surrounding the byssal thread. Structural variation occurred when the byssal thread was differentially stretched. Four-stranded helical primary fasciculi, which form a stable rope-like structure, become evident after removal of the cuticle. The primary fasciculi consist of bundles of hundreds of parallel secondary fasciculi, each measuring about 5 μm in diameter. All evidence indicates that the byssus of the pink heelsplitter has a significantly different macrostructure and microstructure than the permanent byssus of the marine mussel Mytilus. Byssogenesis ceases when juveniles exceed 30 mm in length, although it varies greatly even among juveniles of similar size. Byssus formation is influenced by substrate type. The unique characteristics of the byssus have important advantages for survival, transition, and aggregation during the early life history. This study not only provides first insight into the structure of the ephemeral byssus and its relationship to freshwater mussel development and growth, but also suggests possibilities for the synthesis of novel biopolymer materials particularly useful in freshwater ecosystems.

  16. Troponin-like regulation in muscle thin filaments of the mussel Crenomytilus grayanus (Bivalvia: Mytiloida).

    PubMed

    Vyatchin, Ilya G; Shevchenko, Ulyana V; Lazarev, Stanislav S; Matusovsky, Oleg S; Shelud'ko, Nikolay S

    2015-10-01

    Muscles of bivalve molluscs have double calcium regulation--myosin-linked and actin-linked. While the mechanism of myosin-linked regulation is sufficiently studied, there is still no consensus on the mechanism of actin-linked regulation. Earlier we showed a high degree of Ca2+-sensitivity of thin filaments from the adductor muscle of the mussel Crenomytilus grayanus (Mytiloida). In order to elucidate the nature of this regulation, we isolated the fraction of minor proteins from the mussel thin filaments, which confers Ca2+-sensitivity to reconstituted actomyosin-tropomyosin. Proteins of this fraction, ABP-19, ABP-20, and ABP-28, were chromatographically purified and identified. According to the results of mass spectrometry and Western blot analysis, as well as by their functional properties, these mussel actin-binding proteins appeared to correspond to the troponin components from the skeletal muscles of vertebrates (TnC, TnI and TnT). The reconstituted mussel troponin complex confers to actomyosin-tropomyosin more than 80% Ca2+-sensitivity. The in vivo molar ratio of actin/tropomyosin/troponin was calculated to be 7:1:0.5, i.e., the content of troponin in mussel thin filaments is two times lower than in thin filaments of skeletal muscles of vertebrates. These data demonstrate that troponin-like regulation found in the catch muscle of the mussel C. grayanus is present at least in two suborders of bivalves: Pectinoida and Mytiloida.

  17. The Complete Maternally and Paternally Inherited Mitochondrial Genomes of a Freshwater Mussel Potamilus alatus (Bivalvia: Unionidae).

    PubMed

    Wen, Hai B; Cao, Zhe M; Hua, Dan; Xu, Pao; Ma, Xue Y; Jin, Wu; Yuan, Xin H; Gu, Ruo B

    2017-01-01

    Doubly uniparental inheritance (DUI) of mitochondrial DNA, found only in some bivalve families and characterized by the existence of gender-associated mtDNA lineages that are inherited through males (M-type) or females (F-type), is one of the very few exceptions to the general rule of strict maternal mtDNA inheritance in animals. M-type sequences are often undetected and hence still underrepresented in the GenBank, which hinders the progress of the understanding of the DUI phenomenon. We have sequenced and analyzed the complete M and F mitogenomes of a freshwater mussel, Potamilus alatus. The M-type was 493 bp longer (M = 16 560, F = 16 067 bp). Gene contents, order and the distribution of genes between L and H strands were typical for unionid mussels. Candidates for the two ORFan genes (forf and morf) were found in respective mitogenomes. Both mitogenomes had a very similar A+T bias: F = 61% and M = 62.2%. The M mitogenome-specific cox2 extension (144 bp) is much shorter than in other sequenced unionid mitogenomes (531-576 bp), which might be characteristic for the Potamilus genus. The overall topology of the phylogenetic tree is in very good agreement with the currently accepted phylogenetic relationships within the Unionidae: both studied sequences were placed within the Ambleminae subfamily clusters in the corresponding M and F clades.

  18. Complete maternal mitochondrial genome of freshwater mussel Aculamprotula tientsinensis (Bivalvia: Unionidae: Unioninae).

    PubMed

    Wu, Rui-Wen; An, Chang-Ting; Wu, Xiao-Ping; Zhou, Chun-Hua; Ouyang, Shan

    2016-11-01

    Aculamprotula tientsinensis is a rare and endemic species of freshwater mussel in China. This study firstly determined the complete F-type mitochondrial genome of A. tientsinensis. The circle genome (15 695 bp) comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, 1 FORF gene. Except for cob, nad5 and nad6, the remaining protein-coding genes initiate with the orthodox start codon (ATG, ATA, ATT). There are 26 non-coding regions in the mitogenome of A. tientsinensis, ranging in size from 1 to 229 bp. The base composition of the genome is A (37.83%), G (12.69%), T (25.43%) and C (24.06%). Gene order is identical to other female species of Unionidae but for Gonideinae. The phylogenetic analyses of Unionidae indicate that A. tientsinensis is closely related to A. tortuosa and A. coreana, which belong to Unioninae. The complete mitogenome can deepen comparative and evolutionary genomics of Unionidae and be more comprehensive to parse the genetic relationship between the species and the ownership beyond species.

  19. Complete maternal mitochondrial genome of freshwater mussel Anodonta lucida (Bivalvia: Unionidae: Anodontinae).

    PubMed

    Song, Xue-Lin; Ouyang, Shan; Zhou, Chun-Hua; Wu, Xiao-Ping

    2016-01-01

    The taxonomy of genus Anodonta is rather ambiguous, as it has great variation on the shell shape. Anodonta lucida is an endemic species of freshwater mussel in China, characterized by shining epidermis. The complete maternal mitochondrial genome of freshwater mussel A. lucida was first determined (GenBank accession no. KF667529). The genome is 16,285 bp long with an AT content of 64.02%. All the 37 typical animal mitochondrial genes are found, including 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes. The genome also contains 24 unassigned regions, ranking from 1 to 830 bp in length, the largest of which is the putative control region (CR). The base composition of the genome is A (36.32%), G (13.01%), T (27.70%) and C (22.98%). Gene order is identical to other species of Unionidae except Gonideinae.

  20. Comparisons of Gymnophallid digeneans from north Pacific and Baltic clams, Macoma balthica (Bivalvia).

    PubMed

    Pekkarinen, M; Ching, H L

    1994-08-01

    Three gymnophallid species in Macoma balthica from the northeastern Pacific Ocean are similar to 3 species in M. balthica from the Baltic Sea. Using light and scanning electron microscopy, we compared the anatomy of the larvae of 2 species of Lacunovermis and of Gymnophallus, and the adults of 2 species of Lacunovermis recovered from incubation on chick allantoic membrane. The third similar pair of Meiogymnophallus multigemmulus and Parvatrema affinis was restudied with light microscopy. Previously described anatomical differences between the 3 pairs of Pacific and Baltic gymnophallids were nullified in this study. Lacunovermis conspicuus Ching, 1965 is synonymized with Lacunovermis macomae (Lebour, 1908), and Gymnophallus gibberosus Loos-Frank, 1971 is synonymized with Gymnophallus somateriae (Levinsen, 1881). Meiogymnophallus multigemmulus Ching, 1965 is synonymized with Parvatrema affinis (Jameson and Nicoll, 1913), becoming M. affinis n. comb.

  1. Oocyte Degeneration Associated with Follicle Cells in Female Mactra chinensis (Bivalvia: Mactridae)

    PubMed Central

    Kim, Sung Han; Chung, Ee-Yung; Lee, Ki-Young

    2014-01-01

    Ultrastructural studies of oocyte degeneration in the oocyte, and the functions of follicle cells during oocyte degeneration are described to clarify the reproductive mechanism on oocyte degeneration of Mactra chinensis using cytological methods. Commonly, the follicle cells are attached to the oocyte. Follicle cells play an important role in oocyte degeneration. In particular, the functions of follicle cells during oocyte degeneration are associated with phagocytosis and the intracellular digestion of products. In this study, morphologically similar degenerated phagosomes (various lysosomes), which were observed in the degenerated oocytes, appeared in the follicle cells. After the spawning of the oocytes, the follicle cells were involved in oocyte degeneration through phagocytosis by phagolysosomes. Therefore, it can be assumed that follicle cells reabsorb phagosomes from degenerated oocytes. In this study, the presence of lipid granules, which occurred from degenerating yolk granules, gradually increased in degenerating oocytes. The function of follicle cells can accumulate reserves of lipid granules and glycogen in the cytoplasm, which can be employed by the vitellogenic oocyte. Based on observations of follicle cells attached to degenerating oocytes after spawning, the follicle cells of this species are involved in the lysosomal induction of oocyte degeneration for the reabsorption of phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves. PMID:25949203

  2. Microbial distribution and abundance in the digestive system of five shipworm species (Bivalvia: Teredinidae).

    PubMed

    Betcher, Meghan A; Fung, Jennifer M; Han, Andrew W; O'Connor, Roberta; Seronay, Romell; Concepcion, Gisela P; Distel, Daniel L; Haygood, Margo G

    2012-01-01

    Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose.

  3. Phylogeny and androgenesis in the invasive Corbicula clams (Bivalvia, Corbiculidae) in Western Europe

    PubMed Central

    2011-01-01

    Background The genus Corbicula is one of the most invasive groups of molluscs. It includes both sexual and androgenetic lineages. The present study re-assessed the different morphotypes and haplotypes of West European Corbicula in order to clarify their taxonomic identification and phylogenetic relationships with American and Asian Corbicula clams. We studied several populations from West European river basins (Meuse, Seine, Rhine and Rhône) through an "integrative taxonomy" approach. We combined morphology, partial mitochondrial COI and cyt b sequences and eleven microsatellite loci. Furthermore, we looked for discrepancies between mtDNA and nrDNA/morphology, indicative of androgenesis between lineages. Results There are three Corbicula morphotypes in Western Europe associated to three mitochondrial lineages and three genotypes. Form R shares the same COI haplotype as the American form A and the Japanese C. leana. Form S and the American form C have the same haplotype, although their morphologies seem divergent. The European form Rlc belongs to the same mitochondrial lineage as both the American form B and the Asian C. fluminea. Interestingly, within each haplotype/genotype or lineage, no genetic diversity was found although their invasive success is high. Moreover, we detected rare mismatches between mtDNA and nrDNA/morphology, indicative of androgenesis and mitochondrial capture between form R and form S and therefore challenging the phylogenetic relatedness and the species status within this genus. The global phylogenetic analysis revealed that the sexual Corbicula lineages seem restricted to the native areas while their androgenetic relatives are widespread and highly invasive. Conclusions We clarified the discrepancies and incongruent results found in the literature about the European morphotypes of Corbicula and associated mitochondrial lineages. The three West European morphotypes belong to three distinct nuclear and mitochondrial lineages. However mitochondrial capture occurs in sympatric populations of forms R and S. The species status of the morphotypes therefore remains doubtful. Moreover the androgenetic lineages seem widely distributed compared to their sexual relatives, suggesting that androgenesis and invasive success may be linked in the genus Corbicula. PMID:21619630

  4. A biomechanical model of rock drilling in the piddock Barnea candida (Bivalvia; Mollusca).

    PubMed

    Nederlof, Ralf; Muller, Mees

    2012-11-07

    The bivalve Barnea candida (Pholadacea) makes its burrow in clay, soft rock and peat. Barnea has developed a number of adaptations to accommodate this lifestyle. Four muscles enable burrowing. These are situated around a dorsal pivot in such a way that the piddock is able to rotate the shells around two approximate orthogonal axes. The anterior adductor muscle anterior (AAM-A) and the posterior adductor muscle rotate the shells around a dorso-ventral axis; the anterior adductor muscle posterior (AAM-P) and the ventral adductor muscle rotate the shells around an antero-posterior axis. The AAM-A and the AAM-P have evolved from a single anterior adductor muscle and are attached to a piece of the shell that is folded inside out, the umbonal reflection. At the dorsal side of the piddock, the shell margins are reduced. This prevents collision of these margins during movement. Electrical stimulation experiments revealed that the opening of the antero-ventral side of the piddock is faster than its closure. These results were incorporated into a computer model that could simulate shell movements. The computer model allowed predictions about the shapes of burrows and scrape marks. As in Nature, simulated burrows had a long droplet shape with straight scrape marks.

  5. Growth and production of Donax striatus (Bivalvia: Donacidae) from Las Balsas beach, Gibara, Cuba.

    PubMed

    Ocaña, Frank A

    2015-09-01

    Clams of the genus Donax are worldwide the dominating group of the invertebrate community on sandy beaches. They are primary consumers that provide a significant abundance and biomass to the ecosystem. In the Caribbean, Donax striatus has an important role for nature and human, nonetheless studies on the population dynamics of this beach clam are scarce and no information exists on secondary production of this species. Growth parameters and secondary production of D. striatus were estimated from February 2008 to November 2009 at Las Balsas beach, Northeastern Cuba, in order to provide basic information for management purposes. In each month 45 samples were taken by means of a PVC corer of 0.025 m2 area and sieved with a 1 mm mesh. Animals were measured and weighted with and without shell. A total of 5 471 specimens were collected during the sampling period. Shell length ranged from 2.7-33.3 mm. Growth parameters estimated from length frequency data were L∞ = 36.1 mm, K= 0.8/yr and t0= 0.2/yr. The growth performance resulted in values of Φ'= 3.02. Life span was 2.4 yrs and mortality rate was 3.07 /yr. In 2008, mean abundance of D. striatus ranged between 17.1 - 770.7 ind./m2. In 2009 the lowest mean abundance was 34.4 and the highest was 892.5 ind./m2. During 2009 biomass and production was more than twice higher in comparison with 2008. Individual production showed highest values in the 24 mm shell size (3.74 g/m2.yr) and 25 mm (0.71 g/m2.yr), considering mass with shell and without shell, respectively. During 2009 abundance of individuals with 15 mm shell length or more increased resulting in higher biomass and production, compared to 2008. Using the conversion factor of wet mass to ash free dry mass (AFDM), annual production ranged between 2.87-6.11 g AFDM/m2.yr, resulting in a turnover rate (P/B) between 5.11 and 3.47 in 2008 and 2009, respectively. The rapid growth and high turnover rate of D. striatus suggest a rapid recovery of the population. These results support the idea that this beach clam is an important resource at Las Balsas beach. Thus its exploitation must continue with caution, and only at the level of a recreational fishery.

  6. Molecular insights into the taxonomy of Hypanis (Bivalvia, Cardiidae, Lymnocardiinae) in the Black Sea lagoons

    NASA Astrophysics Data System (ADS)

    Popa, Luis; Popa, Oana; Iorgu, Elena; Kelemen, Beatrice; Murariu, Dumitru

    2012-06-01

    In this study, we used data from morphology and three DNA markers to assess the taxonomic status of the putative bivalve species Hypanis colorata and Hypanis angusticostata in a Black Sea lagoon, the Razelm Lake in Romania. The morphological data (the shape of shell ribs and the multivariate analysis of morphometric variance of three variables constructed as the ratios between the main dimensions of the shell) confirmed that the two analyzed species are distinct morphological entities. Three molecular markers, one from the nuclear genome (18S rRNA) and two from the mitochondrial genome (16S rRNA and COI), showed extremely reduced sequence divergence (0-0.1%) between the two putative species. Based on these results, we suggest that H. angusticostata and H. colorata are morphotypes of a single species.

  7. [Mollusc diversity in an Arca zebra (Mollusca: Bivalvia) community, Chacopata, Sucre, Venezuela].

    PubMed

    Prieto, A S; Ruiz, L J; García, N; Alvarez, M

    2001-06-01

    The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H' = 2.087, J' = 0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A Log series model applied to species abundance data showed a straight line with a diversity index alpha of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69% in number of individuals and 72% of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 +/- 263 g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela.

  8. Identifying the true oysters (Bivalvia: Ostreidae) with mitochondrial phylogeny and distance-based DNA barcoding.

    PubMed

    Liu, Jun; Li, Qi; Kong, Lingfeng; Yu, Hong; Zheng, Xiaodong

    2011-09-01

    Oysters (family Ostreidae), with high levels of phenotypic plasticity and wide geographic distribution, are a challenging group for taxonomists and phylogenetics. As a useful tool for molecular species identification, DNA barcoding might offer significant potential for oyster identification and taxonomy. This study used two mitochondrial fragments, cytochrome c oxidase I (COI) and the large ribosomal subunit (16S rDNA), to assess whether oyster species could be identified by phylogeny and distance-based DNA barcoding techniques. Relationships among species were estimated by the phylogenetic analyses of both genes, and then pairwise inter- and intraspecific genetic divergences were assessed. Species forming well-differentiated clades in the molecular phylogenies were identical for both genes even when the closely related species were included. Intraspecific variability of 16S rDNA overlapped with interspecific divergence. However, average intra- and interspecific genetic divergences for COI were 0-1.4% (maximum 2.2%) and 2.6-32.2% (minimum 2.2%), respectively, indicating the existence of a barcoding gap. These results confirm the efficacy of species identification in oysters via DNA barcodes and phylogenetic analysis.

  9. Inheritance of the general shell color in the scallop Argopecten purpuratus (Bivalvia: Pectinidae).

    PubMed

    Winkler, F M; Estévez, B F; Jollán, L B; Garrido, J P

    2001-01-01

    Although some external coloration and pigmentation patterns in molluscan shells may be attributable to environmental factors, most variation in these phenotypic characters depends on uncomplicated genetic mechanisms. Genetic research on inheritance of color variations in the north-Chilean scallop (Argopecten purpuratus) has now been expanded to analyze color segregation in juvenile scallops produced under controlled conditions employing self- and cross-fertilization. Calculations from the results were used for comparison with different numerical models based on Mendelian inheritance, and results were also obtained on the inheritance of a dorsoventral white line often observed on the left (upper) valve in this species. The results confirmed the hereditary basis for color variation in the shell of this scallop, suggesting a simple, dominant model of epistasis to explain the distribution of the different color variants observed (purple, brown, orange, yellow, and white). The presence of the white line may be controlled by a recessive allele with simple Mendelian traits on a locus distinct from those that control color variation.

  10. [Energy metabolism and body mass ratio in bivalves mollusca (Mollusca: Bivalvia)].

    PubMed

    Vladimirova, I G; Kleĭmenov, S Iu; Radzinskaia, L I

    2003-01-01

    On the basis of experimental and published data, the interspecific and intraspecific (ontogenetic) dependence of energy metabolism on body weight in bivalves was calculated. Changes in the parameters of intraspecific allometric dependence under the effect of environmental factors were analyzed. The rate of comparable standard metabolism (coefficient a at k = 0.76) was shown to vary in different taxonomic and zoogeographic groups of bivalves.

  11. Arctica islandica (Bivalvia): A unique paleoenvironmental archive of the northern North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Schöne, Bernd R.

    2013-12-01

    High-resolution environmental proxy data from the extratropical North Atlantic prior to the instrumental era are of critical importance to decipher processes and mechanisms of global change. In this regard, shells of the extremely long-lived bivalve mollusc, Arctica islandica (Linnaeus, 1767), have gained particular attention during the last decade because they serve as reliable, subseasonally resolved multi-proxy archives of environmental variability in that very region. With a lifespan of more than 500 years, A. islandica is the longest-lived solitary animal. Its shell grows periodically throughout life and contains distinct annual and daily growth increments. These growth patterns function as a calendar that can be used to place each shell portion into a precise temporal context. Furthermore, changing environmental conditions are encoded in the shells in the form of variable increment widths and geochemical properties. By means of cross-dating, growth increment width chronologies from different specimens can be combined into much longer time-series, so-called composite or master chronologies, covering centuries to millennia and many generations of bivalves. The present paper provides a comprehensive review of research on this species with a special focus on long-term climate and environmental reconstructions using isotopes, trace and minor elements and variations in shell growth. This review also highlights challenges involved with the interpretation of proxy data obtained from A. islandica and identifies future research needs. A. islandica does not easily reveal its secrets. It needs a holistic approach to unlock the multi-proxy records stored in their shells. The goal of this paper is to increase the recognition of this high-potential natural archive and encourage future interdisciplinary research.

  12. The complete mitochondrial genome of Solemya velum (Mollusca: Bivalvia) and its relationships with Conchifera

    PubMed Central

    2013-01-01

    Background Bivalve mitochondrial genomes exhibit a wide array of uncommon features, like extensive gene rearrangements, large sizes, and unusual ways of inheritance. Species pertaining to the order Solemyida (subclass Opponobranchia) show many peculiar evolutionary adaptations, f.i. extensive symbiosis with chemoautotrophic bacteria. Despite Opponobranchia are central in bivalve phylogeny, being considered the sister group of all Autobranchia, a complete mitochondrial genome has not been sequenced yet. Results In this paper, we characterized the complete mitochondrial genome of the Atlantic awning clam Solemya velum: A-T content, gene arrangement and other features are more similar to putative ancestral mollusks than to other bivalves. Two supranumerary open reading frames are present in a large, otherwise unassigned, region, while the origin of replication could be located in a region upstream to the cox3 gene. Conclusions We show that S. velum mitogenome retains most of the ancestral conchiferan features, which is unusual among bivalve mollusks, and we discuss main peculiarities of this first example of an organellar genome coming from the subclass Opponobranchia. Mitochondrial genomes of Solemya (for bivalves) and Haliotis (for gastropods) seem to retain the original condition of mollusks, as most probably exemplified by Katharina. PMID:23777315

  13. Long-term decline in freshwater mussels (Bivalvia: Unionidae) of the western basin of Lake Erie

    USGS Publications Warehouse

    Nalepa, Thomas F.; Manny, Bruce A.; Roth, James C.; Mozley, Samuel C.; Schloesser, Donald W.

    1991-01-01

    Long-term trends in the abundance of unionids in the western basin of Lake Erie were examined from data collected at 17 stations in 1961, 1972, and 1982. The mean number of unionids at these stations declined over this time period, decreasing from 10 m−2 in 1961, to 6 m−2 in 1972, down to 4 m−2 in 1982. This decline in abundance was reflected in the decrease in the number of stations where mussels were found; unionids were found at 16 of the 17 stations in 1961, but at only 6 stations in 1982. Reasons for the decrease in the unionid population are not generally apparent, but are probably related to the decline in water quality and periods of low oxygen levels over the time period of the surveys.

  14. Size-differential feeding in Pinna nobilis L. (Mollusca: Bivalvia): Exploitation of detritus, phytoplankton and zooplankton

    NASA Astrophysics Data System (ADS)

    Davenport, John; Ezgeta-Balić, Daria; Peharda, Melita; Skejić, Sanda; Ninčević-Gladan, Živana; Matijević, Slavica

    2011-04-01

    The endangered fan shell Pinna nobilis is a large bivalve mollusc (<120 cm shell length) endemic to the Mediterranean that lives one-third buried in soft substrata, generally in shallow coastal waters. We hypothesised that P. nobilis of different sizes would ingest different food sources, because small fan shells will inhale material from closer to the substratum than do large fan shells. We studied stomach contents and faeces of 18 fan shells, 6 small (mean 23.0 cm length), 6 medium-sized (mean 41.5 cm length) and 6 large (mean 62.7 cm length) living in a small area of a low-energy coastal detritic bottom characterised by mud, sand and macroalgae at Mali Ston Bay, Croatia. We found that all P. nobilis ingested copious quantities of undetermined detritus (probably at least 95% of ingested material), phytoplankton, micro and mesozooplankton and pollen grains. Large P. nobilis stomach contents showed a preponderance of water column calanoid copepods, while small fan shells had higher numbers of bivalve larvae. All fan shells took in high numbers of harpacticoid copepods that are benthonic, feeding on microbial communities of detritus and benthic vegetation. There was also a significant selection of phytoplankton species, some apparently occurring between inhalation and ingestion. The stomach contents of small P. nobilis had a higher organic matter content than either medium-sized or large fan shells; this indicated that small fan shells ingested detritus of higher organic content than did larger P. nobilis. As the faeces of all P. nobilis had similar organic matter content, this also indicates higher assimilation efficiencies in small fan shells. The demonstration of differential dietary selectivity by different sized animals has implications for future trophic studies of this endangered species. This study also provides the first demonstration of predation on zooplankton by P. nobilis.

  15. Molecular Cytogenetics in Trough Shells (Mactridae, Bivalvia): Divergent GC-Rich Heterochromatin Content

    PubMed Central

    García-Souto, Daniel; Pérez-García, Concepción; Kendall, Jack; Pasantes, Juan J.

    2016-01-01

    The family Mactridae is composed of a diverse group of marine organisms, commonly known as trough shells or surf clams, which illustrate a global distribution. Although this family includes some of the most fished and cultured bivalve species, their chromosomes are poorly studied. In this work, we analyzed the chromosomes of Spisula solida, Spisula subtruncata and Mactra stultorum by means of fluorochrome staining, C-banding and fluorescent in situ hybridization using 28S ribosomal DNA (rDNA), 5S rDNA, H3 histone gene and telomeric probes. All three trough shells presented 2n = 38 chromosomes but different karyotype compositions. As happens in most bivalves, GC-rich regions were limited to the nucleolus organizing regions in Spisula solida. In contrast, many GC-rich heterochromatic bands were detected in both Spisula subtruncata and Mactra stultorum. Although the three trough shells presented single 5S rDNA and H3 histone gene clusters, their chromosomal locations differed. Regarding major rDNA clusters, while Spisula subtruncata presented a single cluster, both Spisula solida and Mactra stultorum showed two. No evidence of intercalary telomeric signals was detected in these species. The molecular cytogenetic characterization of these taxa will contribute to understanding the role played by chromosome changes in the evolution of trough shells. PMID:27537915

  16. [The testing of growth functions for the length of Siliqua patula (Bivalvia) (author's transl)].

    PubMed

    Sager, G

    1980-01-01

    After preceding investigations of the author into increase and growth functions of organic matter the gained formulae are tested together with the classical functions. As an example the razor clam siliqua patula from the Alaskan coast seems rather well fitted because of the number of length measurements and the existence of an inflexion point of the growth curve. Non linear regressions are exercised following the Paul-method. Results are not seldom unexpected, sometimes leaving firmly introduced functions with smaller chances than recently developed ones. The number of parameters of the functions will not necessarily increase the quality of approximation. The best results arise from the increase ansatz W = k Wm/tp proposed by the author Sager 1979c).

  17. Reproductive Cycle of Hard Clam, Meretrix lyrata Sowerby, 1851 (Bivalvia: Veneridae) from Sarawak, Malaysia

    PubMed Central

    Hamli, Hadi; Idris, Mohd Hanafi; Rajaee, Amy Halimah; Kamal, Abu Hena Mustafa

    2015-01-01

    A study of the reproductive cycle of the hard clam, Meretrix lyrata, was documented based on histological observation and Gonad Index (GI). Samples were taken from estuarine waters of the Buntal River in Sarawak, Malaysia. The gonad of M. lyrata started to develop in September 2013. Gametogenesis continued to develop until the maturation and spawning stage from February to April 2014. The GI pattern for a one-year cycle showed a significant correlation with chlorophyll a. The corresponding GI with chlorophyll a suggested that the development of the reproductive cycle of M. lyrata required a high amount of food to increase gametogenesis. PMID:26868710

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

    PubMed

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

    2015-12-01

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

  19. Multi-species generalist predation on the stochastic harvested clam Tivela mactroides (Mollusca, Bivalvia)

    NASA Astrophysics Data System (ADS)

    Turra, Alexander; Fernandez, Wellington S.; Bessa, Eduardo; Santos, Flavia B.; Denadai, Márcia R.

    2015-12-01

    Top-down control is an important force modulating the abundance of prey and structuring marine communities. The harvested trigonal clam Tivela mactroides is hypothesized to be part of the diet of a variety of marine organisms, with its stock influencing predator abundance and being influenced by them. Here we analyzed the diet of potential predators of T. mactroides in Caraguatatuba Bay, northern coast of São Paulo State, Brazil, to identify the main consumers of this marine resource, and also to address the importance of this clam in the diet of each predator. Samples were taken year-round by trawls; all specimens collected were identified and measured and the food items identified and quantified. Twenty-one species consumed T. mactroides, whose importance in the diet varied greatly in both the volume ingested and the frequency of occurrence (pompano Trachinotus carolinus > blue crab Callinectes danae > starfish Astropecten marginatus). Top-down influence on T. mactroides was also dependent on the abundance of consumers (yellow catfish Cathorops spixii > rake stardrum Stellifer rastrifer > barred grunt Conodon nobilis > A. marginatus). Considering the mean volume ingested, the frequency of occurrence of T. mactroides in the diet, and the relative abundance of consumers, the predators that most influenced T. mactroides were T. carolinus, A. marginatus, and C. danae, in decreasing order. Large numbers of small-sized individuals of T. mactroides (<10 mm) were generally preyed upon by A. marginatus, which may have a stronger effect on clam abundance in comparison to C. danae and T. carolinus, which preyed upon larger clams. In conclusion, the results of this study indicate that predators' consumption of T. mactroides in Caraguatatuba Bay can influence its stocks, mainly due to the type and/or abundance of predator species, the volume and number of individuals of T. mactroides preyed upon, and the temporal variations in the abundance of predators.

  20. External morphology of spermatozoa and spermatozeugmata of the freshwater mussel Truncilla truncata (Mollusca: Bivalvia: Unionidae)

    USGS Publications Warehouse

    Waller, D.L.; Lasee, B.A.

    1997-01-01

    Truncilla truncata males release spherical aggregates of spermatozoa, called spermatozeugmata, at spawning. Sperm aggregates from other bivalve species have been described, but few detailed studies exist of the morphology of unionid spermatozeugmata and spermatozoa. We provide the first description of the external morphology of spermatozeugmata and spermatozoa of T. Truncata. The spermatozeugmata had an inside diameter of 76 mu m and contained 8000-9000 spermatozoa. Heads of spermatozoa were directed toward the center of the sphere into a translucent shell; tails were arranged radially and caused the spermatozeugmata to rotate. Spermatozoa of T. Truncata measured 3.3 mu m in length (excluding tail) and each had a head, a midpiece and a flagellum. We also documented the release of spermatozeugmata in two additional unionid species, Lampsilis cardium and Amblema plicata plicata.

  1. The Complete Maternally and Paternally Inherited Mitochondrial Genomes of a Freshwater Mussel Potamilus alatus (Bivalvia: Unionidae)

    PubMed Central

    Hua, Dan; Xu, Pao; Ma, Xue Y.; Jin, Wu; Yuan, Xin H.; Gu, Ruo B.

    2017-01-01

    Doubly uniparental inheritance (DUI) of mitochondrial DNA, found only in some bivalve families and characterized by the existence of gender-associated mtDNA lineages that are inherited through males (M-type) or females (F-type), is one of the very few exceptions to the general rule of strict maternal mtDNA inheritance in animals. M-type sequences are often undetected and hence still underrepresented in the GenBank, which hinders the progress of the understanding of the DUI phenomenon. We have sequenced and analyzed the complete M and F mitogenomes of a freshwater mussel, Potamilus alatus. The M-type was 493 bp longer (M = 16 560, F = 16 067 bp). Gene contents, order and the distribution of genes between L and H strands were typical for unionid mussels. Candidates for the two ORFan genes (forf and morf) were found in respective mitogenomes. Both mitogenomes had a very similar A+T bias: F = 61% and M = 62.2%. The M mitogenome-specific cox2 extension (144 bp) is much shorter than in other sequenced unionid mitogenomes (531–576 bp), which might be characteristic for the Potamilus genus. The overall topology of the phylogenetic tree is in very good agreement with the currently accepted phylogenetic relationships within the Unionidae: both studied sequences were placed within the Ambleminae subfamily clusters in the corresponding M and F clades. PMID:28068380

  2. Spawning, fertilization, and larval development of Potamocorbula amurensis (Mollusca: Bivalvia) from San Francisco Bay, California

    USGS Publications Warehouse

    Nicolini, M.H.; Penry, D.L.

    2000-01-01

    In Potamocorbula amurensis time for development to the straight-hinge larval stage is 48 hr at 15??C. Potamocorbula amurensis settles at a shell length of approximately 135 ??m 17 to 19 days after fertilization. Our observations of timing of larval devdlopment in P. amurensis support the hypothesis of earlier workers that its route of initial introduction to San Francisco Bay was as veliger larvae transported in ballast water by trans-Pacific cargo ships. The length of the larval period of P. amurensis relative to water mass residence times in San Francisco Bay suggests that it is sufficient to allow substantial dispersal from North Bay to South Bay populations in concordance with previous observations that genetic differentiation among populations of P. amurensis in San Francisco Bay is low. Potamocorbula amurensis is markedly euryhaline at all stages of development. Spawning and fertilization can occur at salinities from 5 to 25 psu, and eggs and sperms can each tolerance at least a 10-psu step increase or decrease in salinity. Embryos that are 2 hr old can tolerate the same range of salinities from (10 to 30 psu), and by the time they are 24 hr old they can tolerate the same range of salinities (2 to 30 psu) that adult clams can. The ability of P. amurensis larvae to tolerate substantial step changes in salinity suggests a strong potential to survive incomplete oceanic exchanges of ballast water and subsequent discharge into receiving waters across a broad range of salinities.

  3. Submarine canyons as the preferred habitat for wood-boring species of Xylophaga (Mollusca, Bivalvia)

    NASA Astrophysics Data System (ADS)

    Romano, C.; Voight, J. R.; Company, J. B.; Plyuscheva, M.; Martin, D.

    2013-11-01

    Submarine canyons are often viewed as natural “debris concentrators” on the seafloor. Organic substrates may be more abundant inside than outside canyon walls. To determine the effects of the presence these substrates in the Blanes submarine canyon (NW Mediterranean) and its adjacent western open slope, we deployed wood to study colonizing organisms. Three replicate pine and oak cubes (i.e. most common trees inland) were moored at 900, 1200, 1500 and 1800 m depth and collected after 3, 9 and 12 months. Wood from inside the canyon was significantly more heavily colonized by the five morphotypes of wood-boring bivalves than was wood on the adjacent open slope. Xylophaga sp. A dominated all wood types and locations, with peak abundance at 900 and 1200 m depth. Its growth rate was highest (0.070 mm d-1) during the first three months and was faster (or it recruits earlier) in pine than in oak. Size distribution showed that several recruitment events may have occurred from summer to winter. Xylophaga sp. B, appeared first after 9 months and clearly preferred pine over oak. As the immersion time was the same, this strongly supported a specific association between recruiters and type of substrate. Three morphotypes, pooled as Xylophaga spp. C, were rare and seemed to colonize preferentially oak inside the canyon and pine in the adjacent open slope. Individuals of Xylophaga were more abundant inside the canyon than in nearby off-canyon locations. Blanes Canyon may serve as a long-term concentrator of land-derived vegetal fragments and as a consequence sustain more animals. Are the species richness and abundance of wood-boring bivalves higher inside the canyon than on the adjacent open slope? Do the composition and density of the wood-boring bivalves change with deployment time and depth, as well as on the type of the sunken wood? What is the growth rate of the dominant wood-boring species?

  4. Phylogeny and evolution of ontogeny of the family Oxytomidae Ichikawa, 1958 (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    Lutikov, O. A.; Temkin, I. E.; Shurygin, B. N.

    2010-08-01

    We described ontogenies and reconstructed morphogeneses of hinges in some supraspecific taxa of the bivalve family Oxytomidae Ichikawa, 1958 from the Mesozoic of Russia. The phylogeny of the family is reconstructed using evolutionary and cladistic methods. The appearance of the endemic genus Arctotis Bodylevsky, 1960 in the epicontinental seas of Siberia can be explained in terms of gradual transformations of the ligament and byssal apparatus in the Northern Siberian members of Praemeleagrinella Lutikov et Shurygin, 2009 and Praearctotis Lutikov et Shurygin, 2009.

  5. Temporal dynamics of amino and fatty acid composition in the razor clam Ensis siliqua (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    Baptista, Miguel; Repolho, Tiago; Maulvault, Ana Luísa; Lopes, Vanessa M.; Narciso, Luis; Marques, António; Bandarra, Narcisa; Rosa, Rui

    2014-12-01

    Few studies have been conducted on the temporal dynamics of both amino acid (AA) and fatty acid (FA) profiles in marine bivalves. We investigated the seasonal variation of these compounds in the pod razor clam Ensis siliqua in relation to food availability, salinity, water temperature and reproductive cycle. AA content varied between 46.94 and 54.67 % dry weight (DW), and the AAs found in greater quantity were glutamic acid, glycine and aspartic acid. FA content varied between 34.02 and 87.94 mg g-1 DW and the FAs found in greater quantity were 16:0 and 22:6 n-3. Seasonal trends were observed for AAs and FAs. FAs increased with gametogenesis and decreased with spawning while AA content increased throughout spawning. The effect of increasing temperature and high food availability during the spawning season masked the loss of AAs resulting from gamete release. Still, a comparatively greater increase in the contents of glutamic acid and leucine with spawning indicate their possible involvement in a post-spawning gonad recovery mechanism. A post-spawning decrease in 14:0, 16:0, 16:1 n-7, 18:1 n-7 and 18:1 n-9 is indicative of the importance of these FAs in bivalve eggs. An increase in 18:3 n-3, 18:4 n-3, 20:1 n-9 and 20:2 n-6 during gametogenesis suggests their involvement in oocyte maturation. The FA 22:4 n-6, while increasing with spawning, appears to play a role in post-spawning gonad recovery. Salinity did not have an effect on the AA composition. None of the environmental parameters measured had an effect on FA composition.

  6. Cytogenetics of Anodonta cygnea (Mollusca: Bivalvia) as possible indicator of environmental adversity

    NASA Astrophysics Data System (ADS)

    Carrilho, J.; Leitão, A.; Vicente, C.; Malheiro, I.

    2008-11-01

    Anodonta cygnea is a freshwater clam, belonging to the Unionidae family, which can be found in rivers and lagoons all over Europe and Northern America. As they appear as important case studies for ecological damage assessments, the various species of the Unionidae family have been submitted to a sort of recent studies on their chromosomal or cytogenetic status. In this study we confirmed the diploid chromosome number of 2 n = 38 for this species, and established for the first time the karyotype, which comprised six metacentric, 12 submetacentric and one subtelocentric chromosome pairs. We also found a high percentage of cells with an abnormal number of chromosomes. Considering that karyotype disturbances in Unionids have been previously related with exposure to chemicals, either natural or produced by human activity, we determined the aneuploidy index for our population. The aneuploidy index is an excellent marker for pollutant presence/effect. The animals acclimatized in tap water and in natural water from the lake where the individuals were collected showed different levels of aneuploidy. The higher values were found in tap water. Chromosome analysis techniques seem a suitable tool to study the impact of contaminants referred above, and making A. cygnea a suitable organism for assessment of an eugenic damage in aquatic systems. On the other hand, our results also point out to the importance of doing the acclimatizing process of the collected animals in their own natural water.

  7. Clarifying phylogenetic relationships and the evolutionary history of the bivalve order Arcida (Mollusca: Bivalvia: Pteriomorphia).

    PubMed

    Combosch, David J; Giribet, Gonzalo

    2016-01-01

    The systematics of the bivalve order Arcida constitutes an unresolved conundrum in bivalve systematics. The current definition of Arcida encompasses two superfamilies: Limopsoidea, which includes the recent families Philobryidae and Limopsidae, and Arcoidea, which encompasses the families Arcidae, Cucullaeidae, Noetiidae, Glycymerididae and Parallelodontidae. This classification, however, is controversial particularly with respect to the position and taxonomic status of Glycymerididae. Previous molecular phylogenies were limited either by the use of only a single molecular marker or by including only a few limopsoid and glycymeridid taxa. The challenging nature of Arcida taxonomy and the controversial results of some of the previous studies, prompted us to use a broad range of taxa (55 species), three nuclear markers (18S rRNA, 28S rRNA and histone H3) and a wide range of algorithmic approaches. This broad but stringent approach led to a number of results that differ significantly from previous studies. We provide the first molecular evidence that supports the separation of Arcoidea from Limopsoidea, although the exact position of Glycymerididae remains unresolved, and the monophyly of Limopsoidea is algorithm-dependent. In addition, we present the first time-calibrated evolutionary tree of Arcida relationships, indicating a significant increase in the diversification of arcidan lineages at the beginning of the Cretaceous, around 140Ma. The monophyly of Arcida, which has been supported previously, was confirmed in all our analyses. Although relationships among families remain somehow unresolved we found support for the monophyly of most arcidan families, at least under some analytical conditions (i.e., Glycymerididae, Noetiidae, Philobryidae, and Limopsidae). However, Arcidae, and particularly Arcinae, remain a major source of inconsistency in the current system of Arcida classification and are in dire need of taxonomic revision.

  8. BIOMARKER RESPONSES IN MACOMA NASUTA (BIVALVIA) EXPOSED TO SEDIMENTS FROM NORTHERN SAN FRANCISCO BAY. (R826940)

    EPA Science Inventory

    Abstract

    Our study investigates biomarker responses and survival of Macoma nasuta exposed to sediments collected from six locations in northern San Francisco Bay. Biomarkers analyzed were stress proteins (hsp70) in gill, mantle and digestive gland, lysosomal mem...

  9. Mesozoic Bivalvia from Clerke and Mermaid Canyons, northwest Australian continental slope

    NASA Astrophysics Data System (ADS)

    Grant-Mackie, J. A.

    Four sets of rock samples from two sites off the northwest Australian shelf in 3625-4480 m of water contain macrofaunas, mainly bivalves, of warm shallow-water origin. Mermaid Canyon (16 deg 19 min S, 118 deg 23 min E) provided many samples of oolitic calcarenite containing Pseudopecten (Pseudopecten) dugong n.sp., indicating an Early Jurassic age and Tethyan relationship. Three hand-specimens from the ridge forming the western edge of Clerke Canyon (16 deg 29 min S, 118 deg 30 min E) yielded a Norian coral-?Lima-oyster assemblage and the Norian-Rhaetian bivalve Palaeocardita aff. globiformis (Boettger). The latter shows relationship with south-east Asian (Indonesia-Vietnam-south China) forms.

  10. Life history and propagation of the endangered dromedary pearlymussel (Dromus dromas) (Bivalvia:Unionidae)

    USGS Publications Warehouse

    Jones, J.W.; Neves, R.J.; Ahlstedt, S.A.; Mair, R.A.

    2004-01-01

    The reproduction, demography, and propagation of the endangered dromedary pearlymussel (Dromus dromas) (Lea, 1834) were studied in the Clinch and Powell rivers, Tennessee. Viable populations of the dromedary pearlymussel now occur only in the Clinch and Powell rivers; the species has been extirpated from the remaining portions of its range in the Cumberland and Tennessee river drainages. Females are long-term winter brooders, and they are gravid from October to June. Glochidia are contained in conglutinates that are red to white and resemble freshwater leeches or flatworms. Conglutinates are 20 to 40 mm long and are released through the excurrent aperture. Estimates of fecundity based on 7 gravid females collected from the Clinch River were 55,110 to 253,050 glochidia/mussel. The ages of 66 valves of D. dromas were determined by thin-sectioning and ranged from 3 to 25 y. Annual growth averaged 5 mm/y until age 10 and decreased to ???1.2 mm/ y thereafter. Nineteen fish species were tested for suitability as hosts for glochidia. Ten were confirmed as hosts through induced infestations of glochidia: black sculpin (Cottus baileyi), greenside darter (Etheostoma blennioides), fantail darter (Etheostoma flabellare), snubnose darter (Etheostoma simoterum), tangerine darter (Percina aurantiaca), blotchside logperch (Percina burtoni), logperch (Percina caprodes), channel darter (Percina copelandi), gilt darter (Percina evides), and Roanoke darter (Percina roanoka). Juveniles produced from these hosts were cultured in dishes held in nonrecirculating aquaculture systems containing fine sediment (<105 ??m) and were fed the green alga Nannochloropsis oculata every 2 d. Survival of 2810 newly metamorphosed juveniles was 836 (29.7%) after 1 to 2 wk.

  11. Redescription and anatomy of Diplodonta portesiana (d’Orbigny, 1846) (Bivalvia, Ungulinidae) from Brazil

    PubMed Central

    Romera, Bárbara L. V.; Simone, Luiz R. L.; Cunha, Carlo M.

    2013-01-01

    Abstract The present redescription of Diplodonta portesiana (d’Orbigny, 1846) is the first part of the revision of this genus in the East Atlantic. This species, despite being common in the Atlantic coast, remains poorly known. A detailed shell and anatomical study was conducted based not only on specimens from the type locality’s vicinities but also on samples from other regions. Diagnostic characters for Diplodonta portesiana includes: rounded shell with a small ligament; triangular, short and deep nymph; external micro ornamentation composed of small concavities in a concentric pattern; small adductor muscles; reduced pedal gape; pair of long hemipalps with a large area covered by folds; stomach with four ducts leading to digestive diverticula; and long intestine length. Our study suggests at least two new diagnostic characters to the genus: the two pair of muscles that controls the incurrent and excurrent openings and a residual ring-like tissue surrounding the anterior half of the posterior foot retractor muscle. PMID:23794808

  12. Influence of the invasive Asian clam Corbicula fluminea (Bivalvia: Corbiculidae) on estuarine epibenthic assemblages

    NASA Astrophysics Data System (ADS)

    Ilarri, M. I.; Souza, A. T.; Antunes, C.; Guilhermino, L.; Sousa, R.

    2014-04-01

    One of the most widespread invasive alien species (IAS) in aquatic ecosystems is the Asian clam Corbicula fluminea. Several studies have shown that C. fluminea can cause large-scale changes in macrozoobenthic assemblages; however, very few attempted to investigate the effects of this IAS on mobile epibenthic species, such as fishes and crustaceans. In this context, the influence of C. fluminea on epibenthic species was investigated during one year by comparing the associated epibenthic fauna in three nearby sites of the Minho estuary (NW of the Iberian Peninsula), wherein the abiotic conditions are similar but the density of the Asian clam is highly different. From a total of 13 species, six were significantly influenced by C. fluminea; five responded positively, namely the brown shrimp Crangon crangon, the European eel Anguilla anguilla, the common goby Pomatoschistus microps, the brown trout Salmo trutta fario and the great pipefish Syngnathus acus, whereas the shore crab Carcinus maenas was negatively influenced. However, stomach contents analysis revealed that fish and crustacean species do not feed on C. fluminea, suggesting that this IAS is still not a large component of the diet of higher trophic levels in this estuarine ecosystem. Our results suggest that the structure provided by C. fluminea shells is likely to be one of the main factors responsible for the differences observed. C. fluminea physical structure seems to influence the epibenthic associated fauna, when found in densities higher than 1000 ind./m2, with sedentary small-bodied crustaceans and fishes being mainly attracted by the increasing in habitat complexity and consequent enhancement of heterogeneity and shelter availability.

  13. Non-invasive method to obtain DNA from freshwater mussels (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Henley, W.F.; Grobler, P.J.; Neves, R.J.

    2006-01-01

    To determine whether DNA could be isolated from tissues obtained by brush-swabbing the mantle, viscera and foot, mantle-clips and swabbed cells were obtained from eight Quadrula pustulosa (Lea, 1831). DNA yields from clips and swabbings were 447.0 and 975.3 ??g/??L, respectively. Furthermore, comparisons of sequences from the ND-1 mitochondrial gene region showed a 100% sequence agreement of DNA from cells obtained by clips and swabs. To determine the number of swabs needed to obtain adequate yields of DNA for analyses, the visceras and feet of 5 Q. pustulosa each were successively swabbed 2, 4 and 6 times. DNA yields from the 2, 4 and 6 swabbed mussel groups were 399.4, 833.8 and 852.6 ng/??L, respectively. ND-1 sequences from the lowest yield still provided 846-901 bp for the ND-1 region. Nevertheless, to ensure adequate DNA yield from cell samples obtained by swabbing, we recommend that 4 swab-strokes of the viscera and foot be obtained. The use of integumental swabbing for collection of cells for determination of genetic relationships among freshwater mussels is noninvasive, when compared with tissue collection by mantle-clipping. Therefore, its use is recommended for freshwater mussels, especially state-protected or federally listed mussel species.

  14. Organization pattern of nacre in Pteriidae (Bivalvia: Mollusca) explained by crystal competition

    PubMed Central

    Checa, Antonio G; Okamoto, Takashi; Ramírez, Joaquín

    2006-01-01

    Bivalve nacre is a brick-wall-patterned biocomposite of aragonite platelets surrounded by organic matter. SEM–electron back scatter diffraction analysis of nacre of the bivalve family Pteriidae reveals that early aragonite crystals grow with their c-axes oriented perpendicular to the growth surface but have their a- and b-axes disoriented. With the accumulation of successive lamellae, crystals progressively orient themselves with their b-axes mutually parallel and towards the growth direction. We propose that progressive orientation is a result of competition between nacre crystals at the growth front of lamellae, which favours selection of crystals whose fastest growth axis (b-axis) is oriented parallel to the direction of propagation of the lamella. A theoretical model has been developed, which simulates competition of rhombic plates at the lamellar growth front as well as epitaxial growth of crystals onto those of the preceding lamella. The model predicts that disordered nacre progressively produces bivalve-like oriented nacre. As growth fronts become diffuse (as is the common case in bivalves) it takes longer for nacre to become organized. Formation of microdomains of nacre platelets with different orientations is also reproduced. In conclusion, not only the organic matrix component, but also the mineral phase plays an active role in organizing the final microstructure. PMID:16777720

  15. Epibiotic relationships on Zygochlamys patagonica (Mollusca, Bivalvia, Pectinidae) increase biodiversity in a submarine canyon in Argentina

    NASA Astrophysics Data System (ADS)

    Schejter, Laura; López Gappa, Juan; Bremec, Claudia Silvia

    2014-06-01

    The continental slope of the southern SW Atlantic Ocean has many distinguishable deep submarine canyons, varying in depth and extension. The benthic fauna within one of them, detected in April 2005 by means of a multibeam SIMRAD EM1002 sonar, and located at 43°35‧S to 59°33‧W, 325 m depth, was studied to discuss faunal affinities with the neighbouring Patagonian scallop fishing grounds located at upper slope depths. In order to add faunal information to the previous general study, we studied the epibiotic species settled on Patagonian scallops (the dominant species in the area) collected in the reference sampling site using a 2.5-m mouth-opening dredge, 10 mm mesh size. We sampled 103 scallops with shell heights between 22 and 69 mm; epibionts were recorded on both valves. We found 53 epibiotic taxa, which were most conspicuous on the upper valve. Bryozoa was the most diverse group (34 species) while Polychaeta was the most abundant group, recorded on 94% of the scallops. Stylasteridae (2 species) and Clavulariidae (Cnidaria) conform newly recorded epibionts on Z. patagonica and the sponge Tedania (Tedaniopsis) infundibuliformis also represents a new record for the SW Atlantic Ocean.

  16. Body condition and gametogenic cycle of Galatea paradoxa (Mollusca: Bivalvia) in the Volta River estuary, Ghana

    NASA Astrophysics Data System (ADS)

    Adjei-Boateng, D.; Wilson, J. G.

    2013-11-01

    The reproductive cycle of Galatea paradoxa which is the basis for an artisanal fishery in the Volta River estuary, Ghana, was studied using condition indices and histological methods from March 2008 to July 2009. The cycle is annual with a single spawning event between June and October. Gametogenesis starts in November progressing steadily to a peak in June-July when spawning begins until October when the animal is spent. The condition indices (shell-free wet weight/total wet weight, ash-free dry weight/shell weight and gonad wet weight/shell weight) showed a clear relationship with the gametogenic stage rising from a minimum at stage (I) start of gametogenesis, to their highest values at stages (IIIA) ripe and (IIIB) start of spawning before declining significantly to stage (IV) spent.It is suggested that condition index may prove a valuable technique in fishery management to recognise the reproductive stages of G. paradoxa as it is less expensive and time consuming than histological techniques in addition to being easier to teach to non-specialists. The data presented in this study provide information on the timing of spawning events for G. paradoxa, which is necessary for developing sustainable management strategies and selection of broodstock for aquaculture.

  17. Oceanographic conditions govern shell growth of Arctica islandica (Bivalvia) in surface waters off Northeast Iceland

    NASA Astrophysics Data System (ADS)

    Marali, Soraya; Schöne, Bernd R.

    2015-04-01

    Shells of the long-lived bivalve Arctica islandica provide absolutely dated, highly resolved archives of environmental variability in the extratropical realm. Shell growth rates of contemporaneous A. islandica specimens are synchronized by one or several environmental factor(s), such as seawater temperature, food supply etc. Based on the growth synchrony, increment width records can be combined to composite chronologies. However, according to existing studies, A. islandica specimens from shallow waters do not show synchronous changes in shell growth and may thus not provide information about environmental conditions such as sea surface temperature. Here, we present the first statistically robust composite chronology of A. islandica from unpolluted surface waters (8-23 m) off Northeast Iceland. The complete record spans the time interval of 1835 to 2012. Times of enhanced shell growth coincide with periods of higher temperature and elevated food supply. Instrumental sea surface temperature (SST) during the growing season explains up to 43% of the variation in relative shell growth. However, the correlation strength varies over time. When the environmental conditions at the sampling site were stable over many consecutive years, i.e. one of the two major surface currents (the warm, nutrient-rich Irminger Current or the cold, nutrient-deficient East Icelandic Current) predominated the area over longer time intervals, the growth synchrony among coeval A. islandica weakened and the correlation between shell growth and SSTs was markedly reduced. Conversely, if the habitat was under the alternating influence of both ocean currents, shell growth was stronger correlated to each other and to SST. Thus, environmental variability is required to synchronize shell growth rates within an A. islandica population. This study further enlightens the relationship between bivalve shell growth and environmental variables.

  18. [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.

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

    NASA Astrophysics Data System (ADS)

    Suwanjarat, J.

    1999-11-01

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

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

    PubMed

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

    2012-10-01

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

  1. [Population dynamic of Donax denticulatus (Bivalvia: Donacidae) at Carenero Beach, Southeastern Cuba].

    PubMed

    Ocaña, Frank A; Apín, Yanet C; Cala, Yuself R

    2013-12-01

    Bivalve molluscs of Donax genus are a very important component of macro-invertebrate assemblages of sandy beaches, and some species are of commercial value in different countries. Although in Cuba Donax denticulatus is not a currently exploited species, the information concerning a stock assessment is a basic step for future use of this resource. With the aim to generate new data on this species structure, growth and secondary production, monthly samples of D. denticulatus were taken from a beach of the Southeastern coast of Cuba, from February to December 2008. Samples were taken from four stations located along the beach; three strata were marked (P1, P2 and P3) per station across the intertidal zone. Three replicated samples of sediments were taken from each stratum with a 0.025 m2 PVC core and were posteriorly sieved with a 1 mm mesh. Histograms of shell length were constructed based on 1 mm intervals and growth parameters were estimated using ELEFAN I routine of FISAT. Mean density ranged from 146.67-855.55 ind./m2 and no differences were found among months (ANOVA, p > 0.05) but among strata (Scheffé, p < 0.05). An association of recruits, young and adults abundances with the strata (chi2, p < 0.01) was found. Most of the recruits were found in the upper strata while young and adult individuals were abundant in the mid-lower strata. Size frequency histograms of this population showed recruitment between March-June. Growth parameters estimated by Von Bertalanffy were Linfinity = 27.5 mm and K = 1.5/year; and the life spam was estimated in 1.5 years. Using the length-converted catch curve, the mortality rate (Z) was estimated in 4.97/year. Based in terms of Ash free dry mass (AFDM), mean biomass was estimated in 0.47 g/m2.year and the somatic production in 12.4 g/m2.year. The renewal rate (P/B) estimated for this population was 26.38, the highest among other Donax populations. High densities, fast growth and high somatic production indicate that this population can be exploited for fishing purposes for which some management measures are proposed.

  2. Mechanisms and functional morphology associated with metal transport in Mercenaria mercenaria (Bivalvia:Mollusca)

    SciTech Connect

    Robinson, W.E.; Morse, M.P.

    1984-02-20

    Studies on the morphological and physiological effects of environmental pollutants on both adult and larval marine bivalve molluscs are described. We have established a substantial data base on metals accumulation within individual organs of the quahog, Mercenaria mercenaria. In addition, studies on the transport, detoxification and elimination of cadmium and silver in this important species are reported. We have shown that various components of marine oilwell drilling muds can have deleterious effects on both adult sea scallops, Placopecten magellanicus, and surf clams, Spisula solidissima. For example, both Q-broxin and attapulgite clay, at concentrations as low as 100 mg 1/sup -1/, effected both the integrity of the sea scallop pseudolamellibranch gill and the rate of gill frontal ciliary activity.

  3. Reproductive ecology of Actinonaias ligamentina (Bivalvia:Unionidae) in a regulated river

    USGS Publications Warehouse

    Moles, K.R.; Layzer, J.B.

    2008-01-01

    Factors affecting the reproductive success of freshwater mussels in lotic systems are poorly understood. Gravidity, fecundity, and fertilization success of Actinonaias ligamentina were examined at 4 sites along a 63-km reach of the Green River immediately below the Green River Dam, Kentucky. No gravid females were collected at the site closest to the dam, and the percentage of gravid females at downstream sites ranged from 20 to 36%. Not all females became gravid, despite the presence of early stages of ova in the gonadal fluid. This observation suggests that female A. ligamentina undergo a resting stage and, therefore, might not become gravid every year. Fecundity differed among sites and increased with distance from the dam. Fertilization rates ranged from 32 to 97% among sites and increased with distance from the dam. Fertilization rate was independent of local mussel density and position in the mussel bed. The high fertilization rates observed in the upstream portions of mussel beds indicate that freshwater mussel sperm have the ability to travel to distant females in lotic systems. Therefore, females are not necessarily dependent upon nearby males for fertilization. Successful fertilization of A. ligamentina at low mussel densities in the Green River suggests that natural recovery of rare endangered species might be possible if host fish and suitable conditions for juvenile survival and growth are present. ?? 2008 by The North American Benthological Society.

  4. Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): Conservation implications of range discontinuity

    USGS Publications Warehouse

    King, T.L.; Eackles, M.S.; Gjetvaj, B.; Hoeh, W.R.

    1999-01-01

    A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona, as represented by the four species surveyed in this study, may not be monophyletic.

  5. Distinct symbiont lineages in three thyasirid species (Bivalvia: Thyasiridae) from the eastern Atlantic and Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Rodrigues, Clara F.; Duperron, Sébastien

    2011-04-01

    Thyasiridae are one of the less studied groups of chemosymbiotic bivalves. Here, we investigated symbioses in three different thyasirid species collected at three cold seeps from the Atlantic and Mediterranean. Phylogenetic analysis of bacterial 16S ribosomal RNA gene sequences demonstrated that each thyasirid species harbours a single phylotype of symbiont that belongs to a distinct lineage of putative sulphur-oxidizing Gammaproteobacteria. This result is confirmed by other marker genes (encoding 23S rRNA and APS reductase) and fluorescence in situ hybridization. This work highlights the diversity of bacteria involved in symbiosis with thyasirids and underlines the relevance of this group as a target for future symbiosis studies.

  6. Isolation and characterization of microsatellite loci in Alasmidonta heterodon (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Shaw, K.M.; King, T.L.; Lellis, W.A.; Eackles, M.S.

    2006-01-01

    We developed 13 species-specific microsatellite markers for the federally endangered Atlantic slope unionid Alasmidonta heterodon. Four to 18 alleles per locus were observed among 30 individuals. Observed heterozygosity throughout the loci ranged from 26.9 to 86.2% and averaged 63.6%. Estimates of individual pairwise genetic distances indicated that levels of genetic diversity among loci were sufficient to produce unique multilocus genotypes for all animals surveyed. Randomization tests showed that genotypes for this collection were consistent with Hardy-Weinberg expectations, and no significant linkage disequilibrium was observed between loci. These loci therefore appear suitable for population surveys, kinship assessment and other such applications. ?? 2006 Blackwell Publishing Ltd.

  7. Characteristics of a refuge for native freshwater mussels (Bivalvia: Unionidae) in Lake St. Clair

    USGS Publications Warehouse

    McGoldrick, D.J.; Metcalfe-Smith, J. L.; Arts, M.T.; Schloesser, D.W.; Newton, T.J.; Mackie, G.L.; Monroe, E.M.; Biberhofer, J.; Johnson, K.

    2009-01-01

    The Lake St. Clair delta (??? 100??km2) provides an important refuge for native freshwater mussels (Unionidae) wherein 22 of the ??? 35 historical species co-occur with invasive dreissenids. A total of 1875 live unionids representing 22 species were found during snorkeling surveys of 32 shallow (??? 1??m) sites throughout the delta. Richness and density of unionids and zebra mussel infestation rates varied among sites from 3 to 13 unionid species, 0.02 to 0.12 unionids/m2, and < 1 to 35 zebra mussels/unionid, respectively. Zebra mussel infestation of unionids in the delta appears to be mitigated by dominant offshore currents, which limit densities of zebra mussel veligers in nearshore compared to offshore waters (13,600 vs. 28,000/m3, respectively). Glycogen concentrations in the tissues of a common and widespread species in the delta (Lampsilis siliquoidea) suggest that zebra mussels may be adversely affecting physiological condition of unionids in a portion of the Lake St. Clair delta. Physiological condition and community structure of unionids within the delta may also be influenced by differences in food quantity and quality resulting from the uneven distribution of water flowing from the St. Clair River. The delta likely supports the largest living unionid community in the lower Great Lakes and includes several species that have been listed as Endangered or Threatened in Canada and/or the state of Michigan, making it an important refuge for the conservation of native unionids. Crown Copyright ?? 2009.

  8. Evolutionary history of relict Congeria (Bivalvia: Dreissenidae): unearthing the subterranean biodiversity of the Dinaric Karst

    PubMed Central

    2013-01-01

    Background Patterns of biodiversity in the subterranean realm are typically different from those encountered on the Earth’s surface. The Dinaric karst of Croatia, Slovenia and Bosnia and Herzegovina is a global hotspot of subterranean biodiversity. How this was achieved and why this is so remain largely unresolved despite a long tradition of research. To obtain insights into the colonisation of the Dinaric Karst and the effects of the subterranean realm on its inhabitants, we studied the tertiary relict Congeria, a unique cave-dwelling bivalve (Dreissenidae), using a combination of biogeographical, molecular, morphological, and paleontological information. Results Phylogenetic and molecular clock analyses using both nuclear and mitochondrial markers have shown that the surviving Congeria lineage has actually split into three distinct species, i.e., C. kusceri, C. jalzici sp. nov. and C. mulaomerovici sp. nov., by vicariant processes in the late Miocene and Pliocene. Despite millions of years of independent evolution, analyses have demonstrated a great deal of shell similarity between modern Congeria species, although slight differences in hinge plate structure have enabled the description of the two new species. Ancestral plesiomorphic shell forms seem to have been conserved during the processes of cave colonisation and subsequent lineage isolation. In contrast, shell morphology is divergent within one of the lineages, probably due to microhabitat differences. Conclusions Following the turbulent evolution of the Dreissenidae during the Tertiary and major radiations in Lake Pannon, species of Congeria went extinct. One lineage survived, however, by adopting a unique life history strategy that suited it to the underground environment. In light of our new data, an alternative scenario for its colonisation of the karst is proposed. The extant Congeria comprises three sister species that, to date, have only been found to live in 15 caves in the Dinaric karst. Inter-specific morphological stasis and intra-specific ecophenotypic plasticity of the congerid shell demonstrate the contrasting ways in which evolution in the underground environments shapes its inhabitants. PMID:23388548

  9. Growth, mortality, and reproduction of Tagelus plebeius (Bivalvia: Solecurtidae) in Southeast Brazil

    NASA Astrophysics Data System (ADS)

    da Silva, Camila Fernanda; Corte, Guilherme Nascimento; Yokoyama, Leonardo Querobim; Abrahão, Jolnnye Rodrigues; Amaral, Antônia Cecília Zacagnini

    2015-03-01

    Tagelus plebeius (Lightfoot, 1786) is a stout razor clam that is economically exploited in several countries, including several local fisheries along the Brazilian coast. Despite its wide distribution and economic importance, there are few studies that have examined the population biology of this species. This study aimed to improve the current knowledge about the biology of T. plebeius by investigating its growth and mortality on a subtropical sandy beach in Southeast Brazil over a 1-year period. In addition, the reproduction of T. plebeius was analyzed through qualitative and quantitative histological analyses during the last 7 months of the study. The parameters of the von Bertalanffy growth function were estimated to be L ∞ = 74.14 mm, K = 0.52 year-1, C = 0.47, and WP = 0.94. The instantaneous mortality rate ( Z) was 2.16 year-1, and the life span was 2.58 years. We confirmed variations ( H = 651.35; P < 0.05) in the shell length over the months of the study, and the recruitment was higher—but still low—in summer. Four cohorts were observed in the distribution of shell length frequencies. The sex ratio of the population was 1:1 during the study period, and a synchronism in gonadal development and spawning was found between males and females. The high mortality ( Z) and low recruitment rates can be interpreted as reflecting that the population of T. plebeius is under a low restoration process and could be an indication that this species has an endangered status in the study area.

  10. Chlorine toxicity to early life stages of freshwater mussels (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Valenti, T.W.; Cherry, D.S.; Currie, R.J.; Neves, R.J.; Jones, J.W.; Mair, R.; Kane, C.M.

    2006-01-01

    Chlorine (Cl) is a highly toxic, widely used halogen disinfectant that is present in point-source pollution discharges from wastewater treatment plants and industrial facilities. The U.S. Environmental Protection Agency freshwater criteria for Cl are 19 ??g total residual Cl (TRC)/L as a maximum 1-h average concentration and 11 ??g TRC/L as a maximum 4-d average; however, toxicological data for unionids were not used in these calculations. To address this void in the data, we conducted acute tests with glochidia from several species and 21-d bioassays with three-month-old Epioblasma capsaeformis and three-, six-, and 12-month-old Villosa iris juveniles. The 24-h lethal concentration 50 values for glochidia were between 70 and 220 ??g TRC/L, which are 2.5 to 37 times higher than those reported in other studies for cladocerans. Significant declines in growth and survivorship were observed in the 21-d test with E. capsaeformis at 20 ??g TRC/L. Lowest-observed-adverse- effects concentrations in bioassays with juvenile V. iris were higher (30-60 ??g TRC/L) but showed a significant trend of declining toxicity with increased age. Although endpoints were above water quality criteria, the long life spans of unionids and potential implications of chronic exposure to endangered juvenile mussels still warrant concern. ?? 2006 SETAC.

  11. Morphological differences in Macoma balthica (Bivalvia, Tellinacea) from a Dutch and three southeastern United States estuaries

    NASA Astrophysics Data System (ADS)

    Kamermans, Pauline; Van der Veer, Henk W.; Witte, Johannes IJ.; Adriaans, Ewout J.

    1999-05-01

    Field collections of the bivalve Macoma balthica in the Dutch Wadden Sea and three southeastern United States estuaries revealed morphological differences between populations of the two sides of the Atlantic Ocean. Individuals of the same age showed much larger shell lengths at the American stations. In addition, bivalves of the same body weight had higher siphon weights at the American stations than at the Dutch stations. This difference in siphon size was related to their burying depths. The American population, which invested more in heavier siphons, was able to burrow much deeper into the sediment (up to 30 cm). Deep burial may be an adaptation to avoid exposure to the high southern temperatures. Furthermore, it may serve as a refuge from blue crab predation. The results of our comparison between the southern American population and the European support the suggestion that populations of M. balthica living in these two regions should be considered separate and sibling species.

  12. Lifespan, growth rate, and body size across latitude in marine Bivalvia, with implications for Phanerozoic evolution.

    PubMed

    Moss, David K; Ivany, Linda C; Judd, Emily J; Cummings, Patrick W; Bearden, Claire E; Kim, Woo-Jun; Artruc, Emily G; Driscoll, Jeremy R

    2016-08-17

    Mean body size in marine animals has increased more than 100-fold since the Cambrian, a discovery that brings to attention the key life-history parameters of lifespan and growth rate that ultimately determine size. Variation in these parameters is not well understood on the planet today, much less in deep time. Here, we present a new global database of maximum reported lifespan and shell growth coupled with body size data for 1 148 populations of marine bivalves and show that (i) lifespan increases, and growth rate decreases, with latitude, both across the group as a whole and within well-sampled species, (ii) growth rate, and hence metabolic rate, correlates inversely with lifespan, and (iii) opposing trends in lifespan and growth combined with high variance obviate any demonstrable pattern in body size with latitude. Our observations suggest that the proposed increase in metabolic activity and demonstrated increase in body size of organisms over the Phanerozoic should be accompanied by a concomitant shift towards faster growth and/or shorter lifespan in marine bivalves. This prediction, testable from the fossil record, may help to explain one of the more fundamental patterns in the evolutionary and ecological history of animal life on this planet.

  13. Transcriptomics provides insight into Mytilus galloprovincialis (Mollusca: Bivalvia) mantle function and its role in biomineralisation.

    PubMed

    Bjärnmark, Nadège A; Yarra, T; Churcher, A M; Felix, R C; Clark, M S; Power, D M

    2016-06-01

    The mantle is an organ common to all molluscs and is at the forefront of the biomineralisation process. The present study used the Mediterranean mussel (Mytilus galloprovincialis) as a model species to investigate the structural and functional role of the mantle in shell formation. The transcriptomes of three regions of the mantle edge (umbo to posterior edge) were sequenced using Illumina technology which yielded a total of 61,674,325 reads after adapter trimming and filtering. The raw reads assembled into 179,879 transcripts with an N50 value of 1086bp. A total of 1363 transcripts (321, 223 and 816 in regions 1, 2 and 3, respectively) that differed in abundance in the three mantle regions were identified and putative function was assigned to 54% using BLAST sequence similarity searches (cut-off less than 1e(-10)). Morphological differences detected by histology of the three mantle regions was linked to functional heterogeneity by selecting the top five most abundant Pfam domains in the annotated 1363 differentially abundant transcripts across the three mantle regions. Calcium binding domains dominated region two (middle segment of the mantle edge). Candidate biomineralisation genes were mined and tested by qPCR. This revealed that Flp-like, a penicillin binding protein potentially involved in shell matrix maintenance of the Pacific oyster (Crassostrea gigas), had significantly higher expression in the posterior end of the mantle edge (region one). Our findings are intriguing as they indicate that the mantle edge appears to be a heterogeneous tissue, displaying structural and functional bias.

  14. Vertical transmission of chemoautotrophic symbionts in the bivalve Solemya velum (Bivalvia: Protobranchia).

    PubMed

    Krueger, D M; Gustafson, R G; Cavanaugh, C M

    1996-04-01

    Adults of the bivalve species Solemya velum live in symbiosis with chemoautotrophic bacteria in specialized gill bacteriocytes. The bacteria play an essential nutritional role in the mature association, fixing CO2 via the Calvin cycle with energy obtained through the oxidation of reduced sulfur compounds. To understand how the continuity of this partnership is maintained between host generations, we investigated the mode of symbiont transfer in S. velum. A diagnostic assay using the polymerase chain reaction and primers specific for the S. velum symbiont ribulose-1,5-bisphosphate carboxylase (RubisCO) gene consistently detected bacterial sequence in female gonad tissue, suggesting the presence of symbiont cells in host ovaries and a vertical mode of symbiont transmission from mother to offspring. Furthermore, intracellular bacteria were present in the developing gills of juveniles that had not yet hatched from the gelatinous capsule in which larval development occurs (11 days after fertilization). By 64 days postfertilization, the typical adult gill ultrastructure of alternating bacteriocytes and symbiont-free-intercalary cells was apparent. Knowledge about the mode of symbiont transfer in S. velum allows further study into the dynamics of host-symbiont interactions in chemoautotrophic associations.

  15. Plant–Pathogen Interaction-Related MicroRNAs and Their Targets Provide Indicators of Phytoplasma Infection in Paulownia tomentosa × Paulownia fortunei

    PubMed Central

    Fan, Guoqiang; Niu, Suyan; Xu, Tong; Deng, Minjie; Zhao, Zhenli; Wang, Yuanlong; Cao, Lin; Wang, Zhe

    2015-01-01

    Paulownia witches’ broom (PaWB) caused by a phytoplasma, has caused extensive losses in the yields of paulownia timber and resulted in significant economic losses. However, the molecular mechanisms in Paulownia that underlie the phytoplasma stress are poorly characterized. In this study, we use an Illumina platform to sequence four small RNA libraries and four degradome sequencing libraries derived from healthy, PaWB-infected, and PaWB-infected 15 mg·L−1 and 30 mg·L−1 methyl methane sulfonate (MMS)-treated plants. In total, 125 conserved and 118 novel microRNAs (miRNAs) were identified and 33 miRNAs responsive to PaWB disease were discovered. Furthermore, 166 target genes for 18 PaWB disease-related miRNAs were obtained, and found to be involved in plant-pathogen interaction and plant hormone signal transduction metabolic pathways. Eleven miRNAs and target genes responsive to PaWB disease were examined by a quantitative real-time PCR approach. Our findings will contribute to studies on miRNAs and their targets in Paulownia, and provide new insights to further understand plant-phytoplasma interactions. PMID:26484670

  16. Plant-Pathogen Interaction-Related MicroRNAs and Their Targets Provide Indicators of Phytoplasma Infection in Paulownia tomentosa × Paulownia fortunei.

    PubMed

    Fan, Guoqiang; Niu, Suyan; Xu, Tong; Deng, Minjie; Zhao, Zhenli; Wang, Yuanlong; Cao, Lin; Wang, Zhe

    2015-01-01

    Paulownia witches' broom (PaWB) caused by a phytoplasma, has caused extensive losses in the yields of paulownia timber and resulted in significant economic losses. However, the molecular mechanisms in Paulownia that underlie the phytoplasma stress are poorly characterized. In this study, we use an Illumina platform to sequence four small RNA libraries and four degradome sequencing libraries derived from healthy, PaWB-infected, and PaWB-infected 15 mg·L-1 and 30 mg·L-1 methyl methane sulfonate (MMS)-treated plants. In total, 125 conserved and 118 novel microRNAs (miRNAs) were identified and 33 miRNAs responsive to PaWB disease were discovered. Furthermore, 166 target genes for 18 PaWB disease-related miRNAs were obtained, and found to be involved in plant-pathogen interaction and plant hormone signal transduction metabolic pathways. Eleven miRNAs and target genes responsive to PaWB disease were examined by a quantitative real-time PCR approach. Our findings will contribute to studies on miRNAs and their targets in Paulownia, and provide new insights to further understand plant-phytoplasma interactions.

  17. Measurement and Modeling of Ecosystem Risk and Recovery for In Situ Treatment of Contaminated Sediments

    DTIC Science & Technology

    2011-02-01

    lubrica 2 2 2 Venerupis philippinarum 4 Unidentified Bivalvia^ 1 Bryozoa + Chordata Molgula spp...Theora lubrica 2 6 Venerupis philippinarum 3 Unidentified Bivalvia^ 1 1 Bryozoa Chordata...lubrica 1 1 3 Venerupis philippinarum 1 1 Unidentified Bivalvia^ Bryozoa + + Chordata Molgula

  18. A new genus and species of Thyasiridae (Mollusca, Bivalvia) from deep-water, Beaufort Sea, northern Alaska

    PubMed Central

    Valentich-Scott, Paul; Powell, Charles L.; II; Lorenson, Thomas D.; Edwards, Brian E.

    2014-01-01

    Abstract Bivalve mollusk shells were collected in 2350 m depth in the Beaufort Sea, Arctic Ocean off northern Alaska. Initial identification suggested the specimens were a member of the bivalve family Thyasiridae, but no known eastern Pacific or Arctic living or fossil thyasirid resembled these deep-water specimens. Comparisons were made with the type of the genera Maorithyas Fleming, 1950, Spinaxinus Oliver & Holmes, 2006, Axinus Sowerby, 1821, and Parathyasira Iredale, 1930. We determined the Beaufort Sea species represents a new genus, herein described as Wallerconcha. These specimens also represent a new species, herein named Wallerconcha sarae. These new taxa are compared with known modern and fossil genera and species of thyasirds. PMID:25589851

  19. [Seasonal variation in proximate composition of mussels Tagelus peruvianus (Bivalvia: Solecurtidae) from the Gulf of Nicoya, Puntarenas, Costa Rica].

    PubMed

    Fonseca Rodríguez, Cristian; Marín-Vindas, Carolina; Chavarría-Solera, Fabián; Agüero Pedro, Toledo

    2011-12-01

    Marine bivalves are a very important food source for human consumption, and species that has not been of traditional use as a fishery resource are gaining interest. Seasonal variation in proximate composition, condition index and energy or caloric content of the mussel Tagelus peruvianus were studied in the Gulf of Nicoya, Puntarenas, Costa Rica. From November 2007 to October 2008, a total of 35 to 40 specimens per month were collected. The proximate composition using the AOAC methods was determined. Results showed that the condition index during December, January and May decreased, indicative of two spawning periods and one gonadal resting phase. Soft tissues were respectively characterized by protein (61.9 +/- 4.3%), carbohydrates (15.7 +/- 2.4%), ash (14.0 +/- 1.9%) and lipids (8.5 +/- 1.7%). The average caloric content was 5.0 +/- 0.1 kcal/g. The results showed that the decrease in protein and fat percentage, and calories content, occurred during the spawning seasons. We suggest that T. peruvianus has an optimal nutritional value for human consumption because of the low-fat and moderate protein content.

  20. 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.

  1. 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.

  2. Long-term monitoring of growth in the Eastern Elliptio, Elliptio complanata (Bivalvia: Unionidae), in Rhode Island: A transplant experiment

    USGS Publications Warehouse

    Kesler, D.H.; Newton, T.J.; Green, L.

    2007-01-01

    The lengths of marked specimens of the freshwater mussel, Eastern Elliptio (Elliptio complanata [Lightfoot 1786]), were monitored annually in 3 lakes in Rhode Island, USA, from 1991 to 2005. Mussels growing in Worden Pond showed a change in mean shell length of only 4.3 mm over 14 y, whereas mussel growth in 2 nearby lakes was 3 to 8x greater than growth in Worden Pond over the same time period. L???, the length at which shell growth stops, was significantly different (p < 0.001) among lakes and ranged from 60.5 to 87.4 mm. Transplant experiments revealed that mussels moved to Worden Pond stopped growing, whereas mussels moved from Worden Pond to the 2 other lakes grew at rates similar to the rates observed for resident mussels in the 2 lakes. Standard water-quality measures did not explain the observed growth cessation and lower condition indices of mussels in Worden Pond. Our growth data are consistent with food limitation. The consistent slow growth of E. complanata in Worden Pond, without high mortality, and its ability to increase growth when placed in environments more favorable than Worden Pond, suggests both growth plasticity and longevity in these animals. ?? 2007 by The North American Benthological Society.

  3. Early life history and spatiotemporal changes in distribution of the rediscovered Suwannee moccasinshell Medionidus walkeri (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Johnson, Nathan A.; Mcleod, John; Holcomb, Jordan; Rowe, Matthew T.; Williams, James D.

    2016-01-01

    Accurate distribution data are critical to the development of conservation and management strategies for imperiled species, particularly for narrow endemics with life history traits that make them vulnerable to extinction. Medionidus walkeri is a rare freshwater mussel endemic to the Suwannee River Basin in southeastern North America. This species was rediscovered in 2012 after a 16-year hiatus between collections and is currently proposed for listing under the Endangered Species Act. Our study fills knowledge gaps regarding changes in distribution and early life history requirements of M. walkeri. Spatiotemporal changes in M. walkeri distribution were displayed using a conservation status assessment map incorporating metadata from 98 historical (1916–1999) and 401 recent (2000–2015) site surveys from museums and field notes representing records for 312 specimens. Recent surveys detected M. walkeri only in the middle Suwannee subbasin (n = 86, 22 locations) and lower Santa Fe subbasin (n = 2, 2 locations), and it appears the species may be extirpated from 67% of historically occupied 10-digit HUCs. In our laboratory experiments, M. walkeri successfully metamorphosed onPercina nigrofasciata (56.2% ± 8.9) and Etheostoma edwini (16.1% ± 7.9) but not on Trinectes maculatus, Lepomis marginatus, Notropis texanus, Noturus leptacanthus, Etheostoma fusiforme, orGambusia holbrooki. We characterize M. walkeri as a lure-displaying host fish specialist and a long-term brooder (bradytictic), gravid from fall to early summer of the following year. The early life history and distribution data presented here provide the baseline framework for listing decisions and future efforts to conserve and recover the species.

  4. Modelling the risk of mortality of Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae) exposed to different turbidity conditions.

    PubMed

    Avelar, W E P; Neves, F F; Lavrador, M A S

    2014-05-01

    The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774), the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU). This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil) and Mogi Guaçu (Porto Ferreira-SP-Brazil) during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU), for periods longer than 120 hours, may be considered a probable cause of mortality for the species.

  5. First molecular phylogeny of the circumtropical bivalve family Pinnidae (Mollusca, Bivalvia): evidence for high levels of cryptic species diversity.

    PubMed

    Lemer, Sarah; Buge, Barbara; Bemis, Amanda; Giribet, Gonzalo

    2014-06-01

    The family Pinnidae Leach, 1819, includes approximately 50 species of large subtidal and coastal marine bivalves. These commercially important species occur in tropical and temperate waters around the world and are most frequently found in seagrass meadows. The taxonomy of the family has been revised a number of times since the early 20th Century, the most recent revision recognizing 55 species distributed in three genera: Pinna, Atrina and Streptopinna, the latter being monotypic. However, to date no phylogenetic analysis of the family has been conducted using morphological or molecular data. The present study analyzed 306 pinnid specimens from around the world, comprising the three described genera and ca. 25 morphospecies. We sequenced the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I, and the nuclear ribosomal genes 18S rRNA and 28S rRNA. Phylogenetic analysis of the data revealed monophyly of the genus Atrina but also that the genus Streptopinna is nested within Pinna. Based on the strong support for this relationship we propose a new status for Streptopinna Martens, 1880 and treat it as a subgenus (status nov.) of Pinna Linnaeus, 1758. The phylogeny and the species delimitation analyses suggest the presence of cryptic species in many morphospecies displaying a wide Indo-Pacific distribution, including Pinna muricata, Atrina assimilis, A. exusta and P. (Streptopinna) saccata but also in the Atlantic species A. rigida. Altogether our results highlight the challenges associated with morphological identifications in Pinnidae due to the presence of both phenotypic plasticity and morphological stasis and reveal that many pinnid species are not as widely distributed as previously thought.

  6. Lucinid bivalves of Guadeloupe: diversity and systematics in the context of the tropical Western Atlantic (Mollusca: Bivalvia: Lucinidae).

    PubMed

    Taylor, Ohn D; Glover, Emily A

    2016-11-23

    Intensive sampling of molluscs from the intertidal to depths of 800 m around the islands of Guadeloupe in the Lesser Antilles (KARUBENTHOS 2012, 2015) recovered 25 species of Lucinidae. All the Guadeloupe species are described and illustrated including details of larval shells and the taxonomy revised within the context of the wider western Atlantic fauna and recent classifications. Concurrent molecular analysis has helped separate frequently confounded species. 'Myrtea' pristiphora is placed in the Leucosphaerine genus Myrtina previously known from the Indo-West Pacific. A second western Atlantic species of Callucina, C. pauperatus previously known from the Pliocene of Jamaica is recognised from the southern Caribbean and off Brazil. The deeper water species 'Myrteopis' lens is placed in Afrolucina previously known from the eastern Atlantic. Lucinids commonly identified as Ctena orbiculata are shown to belong to two distinct species, C. orbiculata in the Gulf of Mexico and Florida and C. imbricatula in the Caribbean. Epicodakia is recognised for the first time in the western Atlantic with E. pectinata widely distributed across the region and E. filiata recorded from deeper water. Three species of Lucina are recognised, Lucina pensylvanica in the Gulf of Mexico and Florida and the similar Lucina roquesana from the Caribbean and Bahamas while the smaller L. aurantia has a wide distribution from central America to the Bahamas. A new species of Parvilucina, P. latens is described; this is similar to P. pectinella but has an internal ligament. The long problematic species 'Codakia' cubana is assigned to Ferrocina. A new genus, Guyanella is introduced for Parvilucina clenchi the smallest known lucinid. A critical reassessment of the lucinid fauna of the western Atlantic Ocean identifies 46 species for the region with 33 of these living at depths less than 200 m. Deeper-water habitats have been much less investigated except at sites of hydrocarbon seeps. Some species are widespread throught the whole region but others have more restricted ranges. Notable are species pairs, for example of Ctena, Lucina, Lucinisca and Parvilucina that are either largely Caribbean or Gulf of Mexico/Floridian in distribution. Although extralimital, two problematic species from the mid-south Atlantic island of St Helena are refigured and placed in Cavilinga.

  7. New lucinid bivalves from shallow and deeper water of the Indian and West Pacific Oceans (Mollusca, Bivalvia, Lucinidae).

    PubMed

    Taylor, John D; Glover, Emily A

    2013-01-01

    Four new species and a new genus of lucinid bivalves are described from shallow and deeper waters in the Indian and West Pacific Oceans. The new genus Scabrilucina (subfamily Lucininae) includes the little-known Scabrilucina victorialis (Melvill, 1899) from the Arabian Sea and Scabrilucina vitrea (Deshayes, 1844) from the Andaman Sea as well as a new species Scabrilucina melvilli from the Torres Strait off northeastern Australia. Ferrocina brunei new species (Lucininae) was recovered from 60 m near oil drilling activities off Borneo; its anatomy confirmed the presence of symbiotic bacteria. Two unusual deeper water species of Leucosphaerinae are described, both species included in on-going molecular analyses; Gonimyrtea ferruginea from 400-650 m in the southwest Pacific and Myrtina reflexa from 200-825 m off Zanzibar and Madagascar.

  8. Exploring the hologenome concept in marine bivalvia: haemolymph microbiota as a pertinent source of probiotics for aquaculture.

    PubMed

    Desriac, Florie; Le Chevalier, Patrick; Brillet, Benjamin; Leguerinel, Ivan; Thuillier, Benoît; Paillard, Christine; Fleury, Yannick

    2014-01-01

    Haemolymph-associated microbiota of marine bivalves was explored for antibacterial activity against important aquaculture pathogens. A collection of 843 strains were cultured from the haemolymph of four bivalve species (Crassostrea gigas, Mytilus edulis, Pecten maximus and Tapes rhomboides) collected by deep-sea diving in the Glenan Archipelago (France). Cell-free culture supernatants were investigated for antibacterial activity using the well-diffusion assay. About 3% of haemolymph-associated cultivable bacteria displayed antibacterial activity toward Gram-negative pathogens. Among the active bacteria, Pseudoalteromonas strains exhibited the highest antibacterial activity. The cell-free culture supernatant of one of them, named hCg-51, was able to inhibit the growth of bacterial pathogens even after drastic dilution (1 : 1024). Hemocyte survival was not significantly altered in the presence of the haemolymph-associated strains assayed. Moreover, a dose-dependent beneficial effect on hemocyte survival rates was observed with the hCg-51 strain. These results suggest that haemolymph microbiota may participate in bivalve protection and therefore confer a health benefit on the host. As a result, the results highlight bivalve haemolymph microbiota as a promising novel source for aquaculture probiotics. This work also gives a first insight into the contribution of the haemolymph-associated microbiota as part of the bivalve 'hologenome'.

  9. Nuclear genes with sex bias in Ruditapes philippinarum (Bivalvia, veneridae): Mitochondrial inheritance and sex determination in DUI species.

    PubMed

    Milani, Liliana; Ghiselli, Fabrizio; Nuzhdin, Sergey V; Passamonti, Marco

    2013-11-01

    Mitochondria are inherited maternally in most metazoans, but in bivalves with Doubly Uniparental Inheritance (DUI) a mitochondrial lineage is transmitted through eggs (F-type), and another through sperm (M-type). In DUI species, a sex-ratio distortion of the progeny was observed: some females produce a female-biased offspring (female-biased family), others a male-biased progeny (male-biased family), and others a 50:50 sex-ratio. A peculiar segregation pattern of M-type mitochondria in DUI organisms appears to be correlated with the sex bias of these families. According to a proposed model for the inheritance of M-type mitochondria in DUI, the transmission of sperm mitochondria is controlled by three nuclear genes, named W, X, and Z. An additional S gene with different dosage effect would be involved in sex determination. In this study, we analyzed structure and localization of three transcripts (psa, birc, and anubl1) with specific sex and family biases in the Manila clam Ruditapes philippinarum. In situ hybridization confirmed the localization of these transcripts in gametogenic cells. In other animals, homologs of these genes are involved in reproduction and ubiquitination. We hypothesized that these genes may have a role in sex determination and could also be responsible for the maintenance/degradation of spermatozoon mitochondria during embryo development of the DUI species R. philippinarum, so that we propose them as candidate factors of the W/X/Z/S system.

  10. Evidence for somatic transcription of male-transmitted mitochondrial genome in the DUI species Ruditapes philippinarum (Bivalvia: Veneridae).

    PubMed

    Milani, Liliana; Ghiselli, Fabrizio; Iannello, Mariangela; Passamonti, Marco

    2014-08-01

    In species with doubly uniparental inheritance (DUI), males are heteroplasmic for two sex-linked mitochondrial genomes (M- and F-mtDNA). While a role of M-mtDNA in male gametogenesis and sperm function is evident, there is an ongoing debate on whether it is transcribed or not in male soma. In this work we report a qPCR analysis in the DUI species Ruditapes philippinarum, showing that M-mtDNA is transcribed in somatic tissues. We observed a correlation between DNA copy numbers of the two analyzed genes, cytochrome b and a novel male-specific mitochondrial gene thought to be involved in DUI (orf21), and between their transcription levels. No correlation between a transcript and its DNA copy number was found, supporting the existence of complex regulatory mechanisms of mitochondrial transcription. We found the highest amount of mtDNA and mtRNA in gonads, likely due to the intense cell proliferation and high energy request for gametogenesis, while the observed variation among specimens is probably related to their different stages of gonad development. Finally, orf21 showed a highly variable transcription in advanced stages of gametogenesis. We hypothesize a differential storage of orf21 transcripts in spermatozoa, representing different paternal contributions to progeny, possibly leading to different developmental outcomes. A transcriptional activity does not necessarily imply the translation of M-mtDNA genes, and studies on mitochondrial proteins and their localization are needed to definitively assess the functioning of male-transmitted mitochondria in male soma. All that considered, the male soma of DUI species may represent an intriguing experimental model to study cytoplasmic genetic conflicts.

  11. Strict sex-specific mtDNA segregation in the germ line of the DUI species Venerupis philippinarum (Bivalvia: Veneridae).

    PubMed

    Ghiselli, Fabrizio; Milani, Liliana; Passamonti, Marco

    2011-02-01

    Doubly Uniparental Inheritance (DUI) is one of the most striking exceptions to the common rule of standard maternal inheritance of metazoan mitochondria. In DUI, two mitochondrial genomes are present, showing different transmission routes, one through eggs (F-type) and the other through sperm (M-type). In this paper, we report results from a multiplex real-time quantitative polymerase chain reaction analysis on the Manila clam Venerupis philippinarum (formerly Tapes philippinarum). We quantified M- and F-types in somatic tissues, gonads, and gametes. Nuclear and external reference sequences were used, and the whole experimental process was designed to avoid any possible cross-contamination. In most male somatic tissues, the M-type is largely predominant: This suggests that the processes separating sex-linked mitochondrial DNAs (mtDNAs) in somatic tissues are less precise than in other DUI species. In the germ line, we evidenced a strict sex-specific mtDNA segregation because both sperm and eggs do carry exclusively M- and F-types, respectively, an observation that is in contrast with a previous analysis on Mytilus galloprovincialis. More precisely, whereas two mtDNAs are present in the whole gonad, only the sex-specific one is detected in gametes. Because of this, we propose that the mtDNA transmission is achieved through a three-checkpoint process in V. philippinarum. The cytological mechanisms of male mitochondria segregation in males and degradation in females during the embryo development (here named Checkpoint #1 and Checkpoint #2) are already well known for DUI species; a Checkpoint #3 would act when primordial germ cells (PGCs) are first formed and would work in both males and females. We believe that Checkpoint #3 is a mere variation of the "mitochondrial bottleneck" in species with standard maternal inheritance, established when their PGCs separate during embryo cleavage.

  12. Behavioral responses of Arctica islandica (Bivalvia: Arcticidae) to simulated leakages of carbon dioxide from sub-sea geological storage.

    PubMed

    Bamber, Shaw D; Westerlund, Stig

    2016-11-01

    Sub-sea geological storage of carbon dioxide (CO2) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO2. This long-lived bivalve mollusc is widely distributed throughout the North Sea, an area where geological storage is currently taking place and where there are plans to expand this operation significantly. A recently published model has predicted a maximum drop of 1.9pH units in seawater at the point source of a substantial escape of CO2 from sub-sea geological storage in this region. Valve movements of A. islandica exposed to reduced pH seawater were recorded continuously using Hall effect proximity sensors. Valve movement regulation is important for optimising the flow of water over the gills, which supplies food and facilitates respiration. A stepwise reduction in seawater pH showed an initial increase in both the rate and extent of valve movements in the majority of individuals tested when pH fell to 6.2 units. Exposing A. islandica to pH 6.2 seawater continuously for seven days resulted in a clear increase in valve movements during the first 40h of exposure, followed by a gradual reduction in activity intensity over the subsequent five days, suggesting acclimation. The ability of both exposed and control bivalves to burrow successfully into sediment on completion of this exposure was very similar. A final exposure trial, testing whether increased valve movements initiated by reduced pH were related to foot extension during attempted burrowing, found no such association. In summary, significant changes in valve behavior did not occur until seawater pH fell to 6.2 units. The response took the form of an increase in valve activity rather than closure. The absence of foot extension coincident with increased valve movements indicates A. islandica were not attempting to burrow, leaving the possibility that valve movements are supporting a respiratory response to hypercapnia. In conclusion, A. islandica appears to be tolerant of reductions in seawater pH equivalent to those predicted for substantial losses of CO2 through leakage from sub-sea geological storage.

  13. The male and female complete mitochondrial genome sequences of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798) (Bivalvia: Unionidae).

    PubMed

    Froufe, Elsa; Gan, Han Ming; Lee, Yin Peng; Carneiro, João; Varandas, Simone; Teixeira, Amílcar; Zieritz, Alexandra; Sousa, Ronaldo; Lopes-Lima, Manuel

    2016-09-01

    Freshwater mussels of the family Unionidae exhibit a particular form of mitochondria inheritance called double uniparental inheritance (DUI), in which the mitochondria are inherited by both male and female parents. The (M)ale and (F)emale mitogenomes are highly divergent within species. In the present study, we determine and describe the complete M and F mitogenomes of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798). The complete M and F mitogenomes sequences are 16 451 bp and 15 787 bp in length, respectively. Both F and M have the same gene content: 13 protein-coding genes (PCGs), 22 transfer RNA (trn) and 2 ribosomal RNA (rrn) genes. Bayesian analyses based on the concatenated nucleotide sequences of 12 PCGs and 2 rrn genes of both genomes, including mitogenome sequences available from related species, were performed. Male and Female lineages are monophyletic within the family, but reveal distinct phylogenetic relationships.

  14. Uptake of methyl mercury by the floater mussel, Pyganodon grandis (Bivalvia, Unionidae), caged in a flooded wetland

    SciTech Connect

    Malley, D.F.; Stewart, A.R.; Hall, B.D. |

    1996-06-01

    A 16.7-ha wetland with a pond at the Experimental Lakes Area, northwestern Ontario, was experimentally flooded to determine causes of elevated waterborne methyl mercury (MeHg) associated with impoundment. Unionid mussels, Pyganodon grandis (formerly Anodonata grandis grandis) were caged in the experimental pond before and after flooding to determine their ability to monitor the elevated waterborne MeHg. Mussels were also caged in a reference wetland pond and in the lake from which they were collected (source lake). Background levels of MeHg in source lake mussel body parts were in the order mantle < gill or visceral remains < foot or kidney and ranged from 108 to 618 ng/g dry weight. Caging in the source lake did not alter MeHg concentration in any body part. Mussels transplanted to the ponds for 90 d showed statistically significant increases above background MeHg in the mantle and visceral remains in the preflood experimental pond (waterborne MeHg 0.24 ng/L). The visceral remains of mussels in the reference pond contained higher levels of MeHg than did those in the preflood experimental pond. Flooding increased waterborne MeHg from 0.1 to 2.3 ng/L and resulted in an increase in MeHg and total Hg (THg) in the mantle, foot, and visceral remains of mussels in the experimental pond. Inexplicably, mussels caged in a hypoxic environment in the experimental pond lost MeHg and THg from all body parts. The authors concluded that not only can P. grandis monitor elevation in waterborne MeHg with flooding, but the MeHg levels in mussels also reflect small differences in background levels of natural MeHg in ponds.

  15. The male and female complete mitochondrial genome sequences of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798) (Bivalvia: Unionidae).

    PubMed

    Froufe, Elsa; Gan, Han Ming; Lee, Yin Peng; Carneiro, João; Varandas, Simone; Teixeira, Amílcar; Zieritz, Alexandra; Sousa, Ronaldo; Lopes-Lima, Manuel

    2015-08-14

    Freshwater mussels of the family Unionidae exhibit a particular form of mitochondria inheritance called double uniparental inheritance (DUI), in which the mitochondria are inherited by both male and female parents. The (M)ale and (F)emale mitogenomes are highly divergent within species. In the present study, we determine and describe the complete M and F mitogenomes of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798). The complete M and F mitogenomes sequences are 16 451 bp and 15 787 bp in length, respectively. Both F and M have the same gene content: 13 protein-coding genes (PCGs), 22 transfer RNA (trn) and 2 ribosomal RNA (rrn) genes. Bayesian analyses based on the concatenated nucleotide sequences of 12 PCGs and 2 rrn genes of both genomes, including mitogenome sequences available from related species, were performed. Male and Female lineages are monophyletic within the family, but reveal distinct phylogenetic relationships.

  16. The male and female complete mitochondrial genome sequences of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798) (Bivalvia: Unionidae).

    PubMed

    Froufe, Elsa; Gan, Han Ming; Lee, Yin Peng; Carneiro, João; Varandas, Simone; Teixeira, Amílcar; Zieritz, Alexandra; Sousa, Ronaldo; Lopes-Lima, Manuel

    2015-08-19

    Freshwater mussels of the family Unionidae exhibit a particular form of mitochondria inheritance called double uniparental inheritance (DUI), in which the mitochondria are inherited by both male and female parents. The (M)ale and (F)emale mitogenomes are highly divergent within species. In the present study, we determine and describe the complete M and F mitogenomes of the Endangered freshwater mussel Potomida littoralis (Cuvier, 1798). The complete M and F mitogenomes sequences are 16 451 bp and 15 787 bp in length, respectively. Both F and M have the same gene content: 13 protein-coding genes (PCGs), 22 transfer RNA (trn) and 2 ribosomal RNA (rrn) genes. Bayesian analyses based on the concatenated nucleotide sequences of 12 PCGs and 2 rrn genes of both genomes, including mitogenome sequences available from related species, were performed. Male and Female lineages are monophyletic within the family, but reveal distinct phylogenetic relationships.

  17. The complete F-type mitochondrial genome of threatened Chinese freshwater mussel Solenaia oleivora (Bivalvia: Unionidae: Gonideinae).

    PubMed

    Huang, Xiao-Chen; Zhou, Chun-Hua; Ouyang, Shan; Wu, Xiao-Ping

    2015-04-01

    The freshwater mussel Solenaia oleivora is considered threatened due to anthropogenic habitat modification and pollution. The complete F-type mitochondrial genome (mitogenome) of S. oleivora was first determined (GenBank accession no. KF296320). The length of this mitogenome is 16,392 bp with an AT content of 59.9%. There are 37 typical animal mitochondrial genes and a putative control region. Within the control region, 5 tandem repeats of a 106 bp element were identified. The gene order rearrangement of cox2-rrnS in F-type mitogenome compared to that of other freshwater mussels, is not unique for S. oleivora, but is shared with all other available freshwater mussels in the subfamily Gonideinae. The complete mitogenome can provide a basic data for the further studies on molecular taxonomy, phylogenetic analyses and conservation genetics.

  18. Reaction of the mussel Mytilus galloprovincialis (Bivalvia) to Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria) concurrent infestation.

    PubMed

    Mladineo, Ivona; Petrić, Mirela; Hrabar, Jerko; Bočina, Ivana; Peharda, Melita

    2012-05-01

    In total 480 individuals of Mytilus galloprovincialis were sampled monthly from October 2009 to September 2010, at the shellfish farm in the Mali Ston Bay, south Adriatic Sea (Croatia) in order to assess the extent of pathology imposed by two parasites, Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria). Although a deteriorating impact on host reproduction or condition index was lacking, we evidenced ultrastructural and functional alteration in host cells at the attachment site. Ultrastructural changes included hemocytic encapsulation of the turbellarian and cell desquamation in medusoid infestation. Caspase positive reaction inferred by immunohistochemistry (IHC) was triggered in cases of turbellarian infestation, in contrast with hydroids, suggesting that the former exhibits more complex host-parasite interaction, reflected in the persistent attempts of the parasite to survive bivalve reaction. We have evidenced that both organisms trigger specific host reaction that although not costly in terms of host reproductive cycle or growth, results in mild tissue destruction and hemocyte activation. A lower degree of tissue reaction was observed in cases of hydroid infestation, compared to turbellarian.

  19. Identification and characterization of the first microsatellite loci for the thick-shelled river mussel Unio crassus (Bivalvia: Unionidae).

    PubMed

    Sell, Jerzy; Mioduchowska, Monika; Kaczmarczyk, Agnieszka; Szymańczak, Robert

    2013-02-01

    The thick-shelled river mussel Unio crassus is critically endangered throughout its range as a result of increasing human activity and habitat loss. Next generation DNA sequencing was used to develop a set of microsatellite markers that can be used for future ecological and population genetics studies of U. crassus. A total of 11 polymorphic loci were identified and characterized using 57 individuals from two Polish populations. Numbers of alleles ranged from 2 to 15 and expected heterozygosity levels ranged from 0.069 to 0.899. Deficiency of heterozygous genotypes was observed in four loci. Marker independence was confirmed with tests for linkage disequilibrium, however, analyses indicated evidence of null alleles in four loci. The microsatellite markers developed specifically for U. crassus provide a valuable tool for future ecological, population genetic assessments, and conservation management of this species.

  20. Is the body condition of the invasive zebra mussel (Dreissena polymorpha) enhanced through attachment to native freshwater mussels (Bivalvia, Unionidae)?

    PubMed

    Pilotto, Francesca; Sousa, Ronaldo; Aldridge, David C

    2016-05-15

    The invasion of zebra mussels, Dreissena polymorpha, into Western Europe and North America has driven widespread ecological change. Attachment of zebra mussels to the shell of native unionoid mussels has resulted in reductions in unionoid abundance and, in extreme cases, their localised extirpations. While the impacts of zebra mussels on infested unionoids are well documented, the possible benefits of the association to the zebra mussel have been little considered. We collected zebra mussels attached to unionoids and to inanimate structures. Zebra mussels attached to unionoids had significantly larger shells, higher standardized body mass and glycogen content than those attached to inanimate substrates, suggesting that D. polymorpha benefits from settling upon unionoids. The body condition of individual zebra mussels was negatively correlated with the number of zebra mussels attached to the unionoid, indicating intraspecific competition. Therefore, zebra mussels seem positively affected through attachment to unionoid mussels, but that these benefits decrease at higher densities of fouling. This association may offer advantages to the spread of zebra mussels within unionoid-rich systems, especially at sites with soft substrates and at the early stages of the invasion process where intraspecific competition is likely to be lower and benefits to the zebra mussels are higher.

  1. Evidence for accumulation of Synechococcus elongatus (Cyanobacteria: Cyanophyceae) in the tissues of the oyster Crassostrea gigas (Mollusca: Bivalvia).

    PubMed

    Avila-Poveda, Omar Hernando; Torres-Ariño, Alejandra; Girón-Cruz, Diego Ademir; Cuevas-Aguirre, Angel

    2014-10-01

    Cyanobacteria appear to have direct relations with mollusks in several aspects. This is the first time, distinguishing Gram-negative cyanoprokaryotic Synechococcus elongatus as bright yellow-gold autofluorescence by Lillie's and Hiss' staining methods on paraffin-embedded tissues of Crassostrea gigas. Three diets: cyanoprokaryotes, cyanoprokaryotes with microalgae, and only microalgae were evaluated. Cyanoprokaryotes were intact, densely bundled, and immersed in the cytosol of the digestive gland, connective tissue, mantle, and gonad of C. gigas, revealing an accumulation systemic without tissue damage observed by histology. Unexpectedly, cyanoprokaryotes were slightly most accumulated with microalgae diet by each of the tissues of the C. gigas than with any other diets. Cyanoprokaryotes tend to be in mean slightly higher in the digestive gland than in any other tissues respectively for each diet, although these values are closely similar to connective tissue. A possible order of exposure of the oyster tissues to accumulation of cyanoprokaryotes was digestive gland, connective tissue, mantle, and gonad. Thereby, the digestive gland could be the major target tissue for the accumulation. Our observations provide a valuable insight regarding the ability of cyanoprokaryotes to penetrate, spread, and remain inside the oyster tissues, suggesting for S. elongatus: (1) a pre-accumulation in oyster tissues from the natural environment, (2) a phagocytosis and/or endocytosis process rather than ingestion and extracellular digestion, (3) an apparent cellular division in the cytosol of oyster tissues, (4) an apparent inter-tissue movement, and (5) a possible endosymbiosis between C. gigas and S. elongatus. Hereby, it is possible that S. elongatus have a well-developed host-endobiont relationship with oysters, and thereby support future work toward a description of the escape and spreading mechanisms of S. elongatus inside the tissues of mollusks, and put forward questions as why it is there? and are the cells active or inactive?

  2. A new species of the genus Policordia (Bivalvia, Verticordioidea, Lyonsiellidae) from off the coast of southern California

    PubMed Central

    Safonova, Lyudmila A.; Barwick, Kelvin L.

    2016-01-01

    Abstract A new species, Policordia hispida, is described and compared with three similar species: Policordia densicostata (Locard, 1898); Policordia pilula (Pelseneer, 1911) and a yet un-described species, Policordia sp. (= Policordia pilula sensu Ivanova, 1977 not Pelseneer, 1911). This is a first record for the genus in the Californian province. PMID:27843379

  3. Reproductive traits of the symbiotic pea crab Austinotheresangelicus (Crustacea, Pinnotheridae) living in Saccostreapalmula (Bivalvia, Ostreidae), Pacific coast of Costa Rica.

    PubMed

    Salas-Moya, Carolina; Mena, Sebastián; Wehrtmann, Ingo S

    2014-01-01

    Pea crabs of the family Pinnotheridae exhibit a symbiotic life style and live associated with a variety of different marine organisms, especially bivalves. Despite the fact that pea crabs can cause serious problems in bivalve aquaculture, the available information about the ecology of these crabs from Central America is extremely limited. Therefore, the present study aimed to describe different reproductive features of the pinnotherid crab Austinotheresangelicus associated with the oyster Saccostreapalmula in the Golfo de Nicoya, Pacific coast of Costa Rica. Monthly sampling was conducted from April to December 2012. Average carapace width (CW) of the 47 analyzed ovigerous females was 7.62 mm. The species produced on average 2677 ± 1754 recently -extruded embryos with an average volume of 0.020 ± 0.003 mm(3); embryo volume increased during embryogenesis by 21%, but did not vary significantly between developmental stages. Brood mass volume varied greatly (between 11.7 and 236.7 mm(3)), and increased significantly with female CW. Females invested on average 76.7% (minimum: 21.7%; maximum: 162.8%) of their body weight in brood production, which confirms a substantially higher energy allocation for embryo production in pinnotherid crabs compared to free-living decapods.

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

    PubMed

    Sokolova, I M; Ringwood, A H; Johnson, C

    2005-09-10

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

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

    PubMed

    Cherkasov, Anton S; Ringwood, Amy H; Sokolova, Inna M

    2006-09-01

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

  6. Larvae of Chironomids (Insecta, Diptera) Encountered in the Mantle Cavity of Zebra Mussels, Dreissena polymorpha (Bivalvia, Dreissenidae)

    NASA Astrophysics Data System (ADS)

    Mastitsky, Sergey E.; Samoilenko, Vera M.

    2005-02-01

    The paper includes data on species composition of chironomid larvae which were encountered in the mantle cavity of zebra mussels (Dreissena polymorpha) within 7 waterbodies in the Republic of Belarus. All were found to be free-living species commonly present in periphyton and/or benthos. A long-term study of the seasonal dynamics of these larvae in Dreissena did not reveal any typical pattern. Our data suppose that chironomids do not have an obligate association with zebra mussels and possibly enter their mantle cavity inadvertently.

  7. Seasonal growth and mortality of juveniles of Lampsilis fasciola (Bivalvia: Unionidae) released to a fish hatchery raceway

    USGS Publications Warehouse

    Hanlon, S.D.; Neves, R.J.

    2006-01-01

    Recent efforts to restore remnant or extirpated populations of freshwater mussels have focused on artificial propagation as an effective and practical conservation strategy. Although artificially cultured juveniles have been produced and released to the wild at various times of the year, no study has investigated the best time of year to release these juveniles. Newly metamorphosed juveniles of the wavyrayed lampmussel (Lampsilis fasciola) were released into a stream-fed fish hatchery raceway during March, June, and September. Growth and survival rates were measured 32, 52, 72, and 92 days post-metamorphosis. Juveniles released in June experienced the greatest growth and survival rates. Juveniles released in September and March experienced high mortality within the first month of release and exhibited poor growth in the cool water conditions typical of those seasons. Overwinter survival exhibited a size-dependent relationship.

  8. Population genetics and phylogeography of freshwater mussels in North America, Elliptio dilatata and Actinonaias ligamentina (Bivalvia: Unionidae).

    PubMed

    Elderkin, Curt L; Christian, Alan D; Metcalfe-Smith, Janice L; Berg, David J

    2008-05-01

    Extrinsic and intrinsic forces combined shape the population structure of every species differently. Freshwater mussels are obligate parasites to a host fish during a juvenile stage (glochidia). Elliptio dilatata (ED) and Actinonaias ligamentina (AL) are co-occurring freshwater mussel taxa with similar North American distribution and share some potential host fish. Using mitochondrial DNA, we determined the genotypes of 190 + individuals from collection sites in at least two tributaries in the Lake Erie and Ohio River watersheds, along with the Ouachita and Strawberry rivers in the southeast. Both species had followed a stepping-stone model of dispersal, with greater pairwise genetic structure among collection sites of ED. Also, phylogeographical analysis for ED found significant geographical structuring of haplotype diversity. Overall, within-population variation increased significantly from north to south, with low genetic diversity in the Strawberry River. We calculated significant among-population structure for both species (ED: Phi(ST) = 0.62, P < 0.001; AL: Phi(ST) = 0.16, P < 0.001). Genetic analysis identified the Ouachita River as an area of significant reproductive isolation for both species. Results for AL indicated dispersal into northern areas from two genetically distinct glacial refugia, where results for ED indicated dispersal followed by low gene flow in northern areas. The conservation strategies for mussels that co-occur in the same 'bed' could be species specific. Species such as ED have management units on the population scale, where AL has a more homogeneous genetic structure across its range.

  9. New molecular phylogeny of Lucinidae: increased taxon base with focus on tropical Western Atlantic species (Mollusca: Bivalvia).

    PubMed

    Taylor, John D; Glover, Emily A; Smith, Lisa; Ikebe, Chiho; Williams, Suzanne T

    2016-11-23

    A new molecular phylogeny of the Lucinidae using 18S and 28S rRNA and cytochrome b genes includes many species from the tropical Western Atlantic as well as additional taxa from the Indo-West Pacific. This study provides a phylogenetic framework for a new taxonomy of tropical Western Atlantic lucinids. The analysis confirmed five major clades-Pegophyseminae, Leucosphaerinae, Myrteinae, Codakiinae and Lucininae, with Monitilorinae and Fimbriinae represented by single species. The Leucosphaerinae are expanded and include Callucina winckworthi and the W. Atlantic Myrtina pristiphora that groups with several Indo-West Pacific Myrtina species. Within the Codakiinae two abundant species of Ctena from the Western Atlantic with similar shells are discriminated as C. orbiculata and C. imbricatula, while in the Indo-West Pacific Ctena bella is a probable species complex. The Lucininae is the most species rich and disparate subfamily with several subclades apparent. Three species of Lucina are recognized in the W. Atlantic L. aurantia, L. pensylvanica and L. roquesana. Pleurolucina groups near to Cavilinga and Lucina, while Lucinisca muricata is more closely related to the E. Pacific L. fenestrata than to the Atlantic L. nassula. A new species of Parvilucina is identified from molecular analyses having been confounded with Parvilucina pectinata but differs in ligament structure. Also, the former Parvilucina clenchi is more distant and assigned to Guyanella.

  10. Application of the morpho-functional analysis of hydrobionts ( Anadara sp. cf. Anadara inaequivalvis Bivalvia) to environmental monitoring

    NASA Astrophysics Data System (ADS)

    Kolyuchkina, G. A.; Miljutin, D. M.

    2013-03-01

    The population dynamics and morphological and functional characteristics (the concentration of hemocytes in the hemolymph and the level of histopathology) of the bivalve Anadara sp. cf. Anadara inaequivalvis were studied in 2005-2007 on the North Caucasian coast of the Black Sea. A drastic decline in the abundance of the bivalves simultaneously with cadmium's exceedence in their soft tissues and bottom sediments were recorded in May of 2007. Six months before the manifestation of the population effects, morphological and functional changes (a decrease in the content of hemocytes in the hemolymph and an increase in the content of brown cells in the connective tissue and lipofuscin-like pigment granules in the digestive gland epithelium) in the bivalves were detected that were the consequences of an external effect (presumably, cadmium intoxication). Thus, the morphological and functional changes of the individual Anadaras may be a promising tool for the early detection of the impact of pollutants on benthic ecosystems.

  11. Biomonitoring study of an estuarine coastal ecosystem, the Sacca di Goro lagoon, using Ruditapes philippinarum (Mollusca: Bivalvia).

    PubMed

    Sacchi, Angela; Mouneyrac, Catherine; Bolognesi, Claudia; Sciutto, Andrea; Roggieri, Paola; Fusi, Marco; Beone, Gian Maria; Capri, Ettore

    2013-06-01

    Coastal lagoons are constantly subjected to releases of chemical pollutants, and so organisms may be exposed to such toxicants. This study investigated through a multivariate approach the physiological status of bivalve Ruditapes philippinarum, farmed in Sacca di Goro lagoon. Biomarkers at different levels of biological organization (catalase, superoxide dismutase, genotoxicity, reburrowing behavior) were evaluated at three sites exposed to different environmental conditions. A seasonal trend was observed, and micronucleus frequency was significantly lowest at the relatively pristine reference site. Enzymatic activity toward oxyradicals be quite efficient since variations in responsiveness were not consistent. However, behavioral impairment was observed in reburrowing rates. Sediment concentrations showed low PAH levels and high natural levels of trace metals Cr and Ni. DistLM statistical analysis revealed a non-significant relationship between selected biomarkers and xenobiotics. Therefore other potentially toxic compounds in admixture at low doses may be involved in driving differing spatial distribution of physiological impairment.

  12. Distribution, genetic analysis and conservation priorities for rare Texas freshwater molluscs in the genera Fusconaia and Pleurobema (Bivalvia: Unionidae)

    PubMed Central

    2012-01-01

    Background Freshwater bivalves in the order Unionoida are considered to be one of the most endangered groups of animals in North America. In Texas, where over 60% of unionids are rare or very rare, 15 species have been recently added to the state’s list of threatened species, and 11 are under consideration for federal listing. Due to insufficient survey efforts in the past decades, however, primary data on current distribution and habitat requirement for most of these rare species are lacking, thus challenging their protection and management. Taxonomic identification of endemic species based on shell morphology is challenging and complicates conservation efforts. In this paper we present historic and current distributional data for three rare Texas species, Fusconaia askewi, F. lananensis, and Pleurobema riddellii, collected during our 2003–2011 state-wide surveys and suggest appropriate conservation measures. In addition, we tested the genetic affinities of Fusconaia and similar species collected from eastern Texas and western Louisiana using cox1 and nad1 sequences. Results We found that F. askewi still inhabits four river basins in eastern and northeastern Texas and can be locally abundant, while P. riddellii was found only in one river basin. Pleurobema riddellii was well-separated from F. askewi and grouped with the P. sintoxia clade. The sequences for F. lananensis were very similar to those for F. askewi, with a maximum difference of just over 1% for nad1 and only 0.7% for cox1, similar to the variation between F. askewi alleles. Except for one low difference (1.55%) with the partial cox1 sequence for F. burkei, all other Fusconaia populations, including those from the Calcasieu drainage, differed by over 2.3% for both genes. Conclusions Our study suggested that F. lananensis is not a valid species, and it is likely that only one Fusconaia species (F. askewi or its probable senior synonym F. chunii) is currently present in East Texas, thus simplifying conservation efforts. Distribution range of both these regional endemics (F. askewi and P. riddellii) has been reduced in the last 80 years. PMID:22731520

  13. Acute toxicity and accumulation of the piscicide 3-trifluoromethyl-4- nitrophenol (TFM) in freshwater mussels (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Waller, D.L.; Rach, J.J.; Luoma, J.A.

    1998-01-01

    We compared the acute toxicity and initial accumulation of the piscicide TFM (3-trifluoromethyl-4-nitrophenol) in the freshwater unionacean mussels, Obliquaria reflexa and Fusconaia flava. Acute 48 h toxicity tests were conducted to determine the LC50 values for each species. The initial uptake clearances of TFM were measured by exposing the mussels to [14C]-TFM and counting the radioactivity in four organ tissues (foot, gill, mantle and viscera) over 48 h. TFM was about 2-fold more toxic to O. reflexa (LC50 1.80 mg I-1) than to F. flava (LC50 3.81 mg L-1) and the difference was not explained by accumulation patterns. The initial uptake clearance rates (0-6 h) for the whole body were similar between the species (11.2 ml g-1 h-2 in O. reflexa and 9.5 ml g-1 h-1 in F. flava). The accumulation of TFM residues among the organ tissues was also similar between species. The uptake clearance rates (ml g-1 h-1) of TFM equivalents were generally highest in the gill, but not significantly different than other organ tissues. The normalized concentration of TFM residues (??g per g whole body) was highest in the viscera. The toxicity data suggest that the mortality of both species would be minimal from sea lamprey control treatments with TFM. However, the behavioural effects and accumulation rates also indicate that mussels do not effectively avoid TFM exposure by valve closure.

  14. Acute toxicity and accumulation of the piscicide 3-trifluoromethyl-4-nitrophenol (TFM) in freshwater mussels (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Waller, Diane L.; Rach, Jeffrey J.; Luoma, James A.

    1998-01-01

    We compared the acute toxicity and initial accumulation of the piscicide TFM (3-trifluoromethyl-4-nitrophenol) in the freshwater unionacean mussels, Obliquaria reflexa and Fusconaia flava. Acute 48 h toxicity tests were conducted to determine the LC50 values for each species. The initial uptake clearances of TFM were measured by exposing the mussels to [14C]-TFM and counting the radioactivity in four organ tissues (foot, gill, mantle and viscera) over 48 h. TFM was about 2-fold more toxic to O. reflexa (LC50 1.80 mg l-1) than to F. flava (LC50 3.81 mg L-1) and the difference was not explained by accumulation patterns. The initial uptake clearance rates (0–6 h) for the whole body were similar between the species (11.2 ml g-1 h-2 in O. reflexa and 9.5 ml g-1 h-1 in F. flava). The accumulation of TFM residues among the organ tissues was also similar between species. The uptake clearance rates (ml g-1 h-1) of TFM equivalents were generally highest in the gill, but not significantly different than other organ tissues. The normalized concentration of TFM residues (μg per g whole body) was highest in the viscera. The toxicity data suggest that the mortality of both species would be minimal from sea lamprey control treatments with TFM. However, the behavioural effects and accumulation rates also indicate that mussels do not effectively avoid TFM exposure by valve closure.

  15. Reproductive cycle of Tagelus plebeius (Mollusca: Bivalvia) in the estuary of the Cachoeira River, Ilhéus, Bahia, Brazil.

    PubMed

    Ceuta, L O; Boehs, G

    2012-08-01

    This study characterized the reproductive cycle of the stout razor clam Tagelus plebeius in the estuary of the Cachoeira River, Ilhéus, Bahia, northeastern Brazil. Samples of 20 animals per collection were taken biweekly from August 2005 to August 2006. The 480 specimens were measured on the antero-posterior axis (length) and then removed from the shell. After macroscopic analysis, the gonads were fixed in Davidson's solution, processed by routine histology and stained by Harris hematoxylin and eosin. The gonads of both males and females appeared milky white, without sexual dimorphism. Microscopic analyses indicated a M: F ratio of 1.06: 1 and continuous reproduction of T. plebeius in the region. The period from August to October showed the most intense spawning. This study provides another example of continuous reproduction of bivalves in tropical waters, and because this species is a heavily exploited fishery resource in the region, it draws attention to the need for a management plan aimed at reducing harvests.

  16. Evolutionary Dynamics of rDNA Clusters in Chromosomes of Five Clam Species Belonging to the Family Veneridae (Mollusca, Bivalvia)

    PubMed Central

    Pérez-García, Concepción; Hurtado, Ninoska S.; Morán, Paloma; Pasantes, Juan J.

    2014-01-01

    The chromosomal changes accompanying bivalve evolution are an area about which few reports have been published. To improve our understanding on chromosome evolution in Veneridae, ribosomal RNA gene clusters were mapped by fluorescent in situ hybridization (FISH) to chromosomes of five species of venerid clams (Venerupis corrugata, Ruditapes philippinarum, Ruditapes decussatus, Dosinia exoleta, and Venus verrucosa). The results were anchored to the most comprehensive molecular phylogenetic tree currently available for Veneridae. While a single major rDNA cluster was found in each of the five species, the number of 5S rDNA clusters showed high interspecies variation. Major rDNA was either subterminal to the short arms or intercalary to the long arms of metacentric or submetacentric chromosomes, whereas minor rDNA signals showed higher variability. Major and minor rDNAs map to different chromosome pairs in all species, but in R. decussatus one of the minor rDNA gene clusters and the major rDNA cluster were located in the same position on a single chromosome pair. This interspersion of both sequences was confirmed by fiber FISH. Telomeric signals appeared at both ends of every chromosome in all species. FISH mapping data are discussed in relation to the molecular phylogenetic trees currently available for Veneridae. PMID:24967400

  17. First Report of Anterior Pallial Tentacles in Solen dactylus (Bivalvia: Solenidae) from the Northern Persian Gulf, Iran

    PubMed Central

    Saeedi, Hanieh; Costello, Mark J.; von Cosel, Rudo

    2013-01-01

    Solenidae are deep burrowing bivalves inhabiting intertidal and shallow sub-tidal soft bottom sediments mostly in tropical and sub-tropical areas. Solen dactylus has a restricted distribution within the Indian Ocean. Solen dactylus is frequently found on the sandy-muddy coast of the northern Persian Gulf, Iran. Specimens of S. dactylus were collected since 2006 from Bandar Abbas to study their biology and ecology. During these studies, an unexpected pair of anterior pallial tentacles at the dorsal end of the anterior pallial crest of the mantle was found. In the tentacles, two kinds of epithelial cells (pyramidal and vacuolated) and fibres (radial and longitudinal), and a branch of the pallial nerve located in the centre of a haemocoel, were determined. A possible coherence of a furrow parallel to the anterior shell margin with the presence of anterior pallial tentacles is discussed. All species with long anterior pallial tentacles have anterior shell furrows. Anterior pallial tentacles were found in 10 species of Solenidae from Asia to the Middle East and Europe. The function of the tentacles is unknown. However, more species need to be examined for anterior pallial tentacles and anterior shell furrows to determine if they reflect a common evolutionary history or ecology. PMID:23691053

  18. Prodigious polyphyly in imperilled freshwater pearly-mussels (Bivalvia: Unionidae): a phylogenetic test of species and generic designations

    USGS Publications Warehouse

    Lydeard, Charles; Minton, Russell L.; Williams, James D.

    2000-01-01

    Unionid bivalves or freshwater pearly-mussels (Unionoidea: Unionidae) serve as an exemplary system for examining many of the problems facing systematists and conservation biologists today. Most of the species and genera were described in the late 1800s and early 1900s, but few phylogenetic studies have been conducted to test conventional views of species and classification. Pearly-mussels of Gulf Coastal drainages of the southeastern United States from the Escambia (southern Alabama to Florida) to the Suwannee Rivers (Florida) are a unique fauna comprised of approximately 100 species, with about 30 endemic to the region. In this study, mitochondrial cytochrome c oxidase subunit I and 16S rRNA gene sequences were used to test the monophyly and to estimate evolutionary relationships of five unionid species representing three different genera. The molecular phylogenies depict all three genera as polyphyletic. The prodigious polyphyly exhibited within unionids is due to incorrect notions of homology and false assumptions about missing anatomical data. In contrast, the molecular phylogeny provides evidence to support the recognition of all five unionid species as distinct evolutionary entities. Furthermore, molecular genealogical evidence supports the elevation of Quincuncina infucata (Conrad) of the Suwannee River to species level, for which Q. kleiniana (Lea) is available.

  19. Cytogenetic characterisation of the razor shells Ensis directus (Conrad, 1843) and E. minor (Chenu, 1843) (Mollusca: Bivalvia)

    NASA Astrophysics Data System (ADS)

    González-Tizón, Ana M.; Rojo, Verónica; Vierna, Joaquín; Jensen, K. Thomas; Egea, Emilie; Martínez-Lage, Andrés

    2013-03-01

    The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric-submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric-submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua.

  20. Life cycle, population dynamics, growth and production of Abra segmentum (Mollusca, Bivalvia) at low salinities in a Mediterranean lagoon

    NASA Astrophysics Data System (ADS)

    Kevrekidis, Theodoros; Kasapis, K.; Kalpia, V.

    2009-12-01

    Aspects of the biology of Abra segmentum were investigated at low salinities in a Mediterranean coastal lagoon (Monolimni Lagoon, Northern Aegean Sea). Monthly samples were collected during the period from February 1998 to January 1999. Recruitment occurred from mid-spring to early autumn (0.3-5.7 psu) and recruits grew during summer and autumn (1.2-5.7 psu), while a major part vanished during next autumn, displaying a maximum life span of about 20 months. A positive correlation was found between the percentage of individuals having a shell length of ≤3.5 mm and temperature; age group 0 showed a growth rate of 0.97 mm per month, and the largest individual collected had a 19.76 mm shell length. The population density sharply increased during late spring (0.3-1.2 psu); this increase was followed by a decline during summer and, afterwards, a gradual increase up to late autumn. Secondary production calculated by the size-frequency method gave a mean annual density ( n) of 3,357 individuals m-2, a mean annual biomass ( B) of 21.98 g DW m-2, an annual production ( P) of 73.72 g DW m-2 and a P: B ratio of 3.35. A comparison of the present data with available data of A. segmentum populations from higher salinity habitats revealed that this bivalve in the study area showed a life history pattern similar to that of other populations of the species and a comparatively high growth rate, maximum body size, n, B, P and P: B ratio. Our findings suggest that the studied aspects of A. segmentum biology could not be markedly affected by low salinities.

  1. Integrative study of a new cold-seep mussel (Mollusca: Bivalvia) associated with chemosynthetic symbionts in the Marmara Sea

    NASA Astrophysics Data System (ADS)

    Ritt, Bénédicte; Duperron, Sébastien; Lorion, Julien; Sara Lazar, Cassandre; Sarrazin, Jozée

    2012-09-01

    Recently, small Idas-like mussels have been discovered living on carbonate crusts associated with cold-seeps in the Marmara Sea. These mussels, here referred to as Idas-like nov. sp., differ morphologically and genetically from another species identified as Idas aff. modiolaeformis, living in the same type of ecosystem in the Nile Deep-Sea Fan (eastern Mediterranean Sea). A phylogenetic analysis confirms the distinction between the two species, which belong to highly divergent lineages. Carbon stable isotope values, as well as the detection of thiotroph-related bacteria in the gill tissue, support the presence of a symbiotic, thiotroph-derived nutrition. In contrast, Idas aff. modiolaeformis displays six different types of symbionts. Finally our size-frequency data suggest that the recruitment is continuous in the examined area. The present study extends the documented distribution of symbiont-bearing mussels to the Marmara Sea, and contributes to the characterisation of biological communities in this recently explored area.

  2. A new species of Pulvinites (Mollusca: Bivalvia) from the upper Paleocene Paspotansa Member of the Aquia Formation in Virginia ( USA).

    USGS Publications Warehouse

    Ward, L.W.; Waller, T.R.

    1988-01-01

    Pulvinites lawrencei n.sp. is described from the upper Paleocene (Landenian Stage) Paspotansa Member of the Aquia Formation in Stafford County, Virginia. This is the first report of a member of the pteriacean family Pulvinitidae in the Tertiary on either side of the Atlantic, the only other post-Mesozoic records of Pulvinites being in the Paleocene of California and the present-day Pacific off southeast Australia. The stratigraphic setting and co-occurring molluscan assemblage of the new species indicate shallow-shelf, open-marine conditions with near normal salinities. -Authors

  3. Differences in absolute and relative growth between two shell forms of Pinna nobilis (Mollusca: Bivalvia) along the Tunisian coastline

    NASA Astrophysics Data System (ADS)

    Rabaoui, Lotfi; Tlig-Zouari, Sabiha; Katsanevakis, Stelios; Belgacem, Walid; Hassine, Oum Kalthoum Ben

    2011-08-01

    This study investigated the absolute and relative growth patterns of the fan mussel Pinna nobilis along the Tunisian coastline, taking into consideration both the variability among different areas and between the two shell forms "combed" and "straight and wide". Five subpopulations of the species were sampled, one from northern, two from eastern and two from southern Tunisia. Various assumptions on the growth patterns were tested based on an information theory approach and multi-model inference. For absolute growth, the assumption of different growth patterns between the two shell forms of P. nobilis and no difference among subpopulations was the most supported by the data. For the same age, "straight and wide" individuals gained on average greater lengths than the "combed" individuals. The absolute growth of the species was found to be asymptotic and the logistic model was the one most supported by the data. As for the relative growth, apart from the classical allometric model Y = aXb, more complicated models of the form ln Y = f(ln X) that either assumed non-linearities or breakpoints were tested in combination with assumptions for possible differences between the two forms and among subpopulations. Among the eight studied relationships between morphometric characters, the classical allometric model was supported in only two cases, while in all other cases more complicated models were supported. Moreover, the assumption of different growth patterns between the two forms was supported in three cases and the assumption of different growth patterns among subpopulations in four cases. Although precise relationships between the morphometric plasticity of the fan mussel and environmental factors have not been proven in this paper, local small scale constraints might be responsible of the different growth patterns observed in the same locality. A possible co-action of genetic factors should be evaluated in the future.

  4. Deep-water Thyasiridae (Mollusca: Bivalvia) from the Oman Margin, Arabian Sea, new species and examples of endemism and cosmopolitanism.

    PubMed

    Oliver, P Graham

    2015-08-05

    Seven species of Thyasiridae are reported from the Oman Margin of the Arabian Sea at depths between 688 m and 3356 m. Hypoxic conditions exist at depths between 400 and 1200 m and three species are restricted to this zone and to the Arabian Sea. Leptaxinus indusarium has also been recorded from the Indus Fan and Channelaxinus investigatoris from off Sri Lanka. A new species Thyasira anassa sp. nov. is described from the hypoxic zone. Another four species are recorded from the abyssal zone where oxygen levels are typical for the deep ocean. Here another new species is described, Parathyasira bamberi sp. nov. but the other species could not be conclusively identified because of close affinity with populations from other oceans.  Deep water Atlantic species Axinulus croulinensis and Mendicula ferruginosa are apparently present in the abyssal Indian Ocean while another thyasirid shell is very close to Channelaxinus excavatus from the Eastern Pacific and C. perplicata from the Atlantic. Accompanying these abyssal thyasirids were other bivalve species, Deminucula atacellana, Limopsis pelagica and Bentharca asperula that cannot be distinguished by morphology from their Atlantic populations. It is concluded that using morphology alone that the abyssal species may well be cosmopolitan in distribution.

  5. Effects of anthracene on filtration rates, antioxidant defense system, and redox proteomics in the Mediterranean clam Ruditapes decussatus (Mollusca: Bivalvia).

    PubMed

    Sellami, Badreddine; Khazri, Abdelhafidh; Louati, Héla; Dellali, Mohamed; Driss, Mouhamed Ridha; Aïssa, Patricia; Mahmoudi, Ezzeddine; Hamouda, Beyrem; Coelho, Ana Varela; Sheehan, David

    2015-07-01

    This study aimed at analyzing the impact of a toxic polyaromatic hydrocarbon (PAH), anthracene (ANT), on Ruditapes decussatus collected from a Tunisian coastal lagoon (Bizerte Lagoon). Filtration rates, several antioxidant enzymes--superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione transferase (GST)--as well as indices of protein oxidation status were determined in various tissues of this bivalve. Specimens were exposed to 100 μg/L of ANT for 2 days. ANT levels were evaluated using HPLC and were detected in the gill and digestive gland at different amounts. ANT exposure altered the behavior of bivalves by changing the siphon movement and decreasing filtration rate significantly. The enzymatic results indicated that ANT exposure affected the oxidative stress status of the gills of R. decussatus. In addition, modification of proteins was detected in the gills using redox proteomics after ANT treatment. Three protein spots were successfully identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-MS). These proteins can be roughly related to muscle contraction function. In contrast, no significant modification of enzymatic and protein responses was detected in the digestive gland after ANT treatment. These data demonstrate that combined behavioral and biochemical analyses are a powerful tool to provide valuable insights into possible mechanisms of toxicity of anthracene in R. decussatus. Additionally, the results highlight the potential of the gill as a valuable candidate for investigating PAH toxicity.

  6. Age determination and growth rate of Mactra chinensis (Bivalvia: Mactridae) by external rings and chondrophore growth bands

    NASA Astrophysics Data System (ADS)

    Kim, Jung Yeon; Na, Jong Hun; Oh, Chul-Woong

    2016-12-01

    Age, growth and mortality of Mactra chinensis were investigated during the period from October 2012 to September 2013 in Busan, South Korea. The monthly variation of the marginal index (MI) of the shell and chondrophore showed that the ring of this species was formed once a year during July. We estimated the age of M. chinensis by reading the external rings on the shell and the growth bands of the chondrophore to compare growth parameters between the two growth characters. The age of this species ranged from 0 to 8 years (shell-based age reading) and from 0 to 10 years (chondrophore-based age reading). Based on external rings and growth bands of chondrophore for the same period, the von Bertalanffy growth functions were expressed by the equation, L t = 101.53[1-exp {-0.15( t + 0.75)}] and L t = 90.03[1-exp {-0.20( t + 0.50)}], respectively. The likelihood test showed that there was a significant difference in L ∞ ( P < 0.001), K ( P < 0.001), to ( P < 0.001) estimated from non-linear regression between the two growth characters.

  7. Direct measurement technique for determining ventilation rate in the deposit-feeding clam Macoma nasuta (bivalvia, tellinaceae)

    SciTech Connect

    Specht, D.T.; Lee, H.

    1989-01-01

    An exposure chamber, the 'clambox', was developed to measure ventilation rate, sediment processing rate, and efficiency of pollutant uptake by Macoma nasuta, Conrad, a surface-deposit-feeding clam. Clams, collected from Yaquina Bay, Oregon, USA, were cemented into a hole in a piece of rubber dental dam so that the inhalant siphons were separated by a membrane. The dental dam was then clamped between two glass chambers. The inhalant and exhalant siphons were thus diirected into separate chambers of the device so that the amount of water or feces discharged into the exhalant camber provided direct measure ventilation rate and sediment processing rate, respectively. The short-term pattern was for ventilation to be intermittently interrupted, essentially ceasing for 12 to 120 min, followed by a short period of active ventilation and then a resumption of the normal rate.

  8. THE INFLUENCE OF SALINITY ON THE HEAT-SHOCK PROTEIN RESPONSE OF POTAMOCORBULA AMURENSIS (BIVALVIA). (R826940)

    EPA Science Inventory

    Abstract

    For biomarkers to be useful in assessing anthropogenic impacts in field studies involving aquatic organisms, they should not be affected by naturally occurring changes in environmental parameters such as salinity. This is especially important in estuarine envi...

  9. Some population parameters of Ruditapes philippinarum (Bivalvia, Veneridae) on the southern coast of the Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Çolakoğlu, Serhat; Palaz, Mustafa

    2014-12-01

    Ruditapes philippinarum, a venerid clam, is a dominant species in the sandy and muddy areas in the coastal waters of the Marmara Sea. Intensive commercial harvesting of this species is conducted in these regions. We studied the population dynamics of R. philippinarum on the southern coast of the Marmara Sea (Bandırma). Samples were collected on a monthly basis between September 2012 and August 2013. Seasonal von Bertalanffy growth parameters using the length-frequency distribution of R. philippinarum were estimated at L ∞ = 67.50 mm and K = 0.33 year-1, and the seasonal oscillation in growth rate was 0.53. The slowest growth period was in January. The growth performance index and potential lifespan were 3.182 and 8.06 years, respectively. The growth relationship was confirmed to have a positive allometric pattern. The average total mortality rate was estimated to be 0.777 year-1, whereas the natural and fishing mortality rates were 0.539 and 0.238 year-1, respectively. The current exploitation rate of R. philippinarum was 0.306. The recruitment pattern peaked during June-August, and spawning occurred between May and August. The results of this study provide valuable information on the status of R. philippinarum stocks.

  10. Growth estimation of mangrove cockle Anadara tuberculosa (Mollusca: Bivalvia): application and evaluation of length-based methods.

    PubMed

    Flores, Luis A

    2011-03-01

    Growth is one of the key processes in the dynamic of exploited resources, since it provides part of the information required for structured population models. Growth of mangrove cockle, Anadara tuberculosa was estimated through length-based methods (ELEFAN I y NSLCA) and using diverse shell length intervals (SLI). The variability of L(infinity), k and phi prime (phi') estimates and the effect of each sample were quantified by jackknife techniques. Results showed the same L(infinity) estimates from ELEFAN I and NSLCA across each SLI used, and all L(infinity) were within the expected range. On the contrary, k estimates differed between methods. Jackknife estimations uncovered the tendency of ELEFAN I to overestimate k with increases in SLI, and allowed the identification of differences in uncertainty (PE and CV) between both methods. The average values of phi' derived from NSCLA1.5 and length-age sources were similar and corresponded to ranges reported by other authors. Estimates of L(infinity), k and (phi' from NSCLA1.5 were 85.97 mm, 0.124/year and 2.953 with jackknife and 86.36mm de L(infinity), 0.110/year de k and 2.914 de phi' without jackknife, respectively. Based on the observed evidence and according to the biology of the species, NSCLA is suggested to be used with jackknife and a SLI of 1.5 mm as an ad hoc approach to estimate the growth parameters of mangrove cockle.

  11. Changes in the freshwater mussel (Bivalvia: Unionidae) fauna of the Bear Creek system of Northwest Alabama and Northeast Mississippi

    USGS Publications Warehouse

    McGregor, S.W.; Garner, J.T.

    2003-01-01

    Drastic reductions in diversity and abundance of mussel populations are documented in many systems. Bear Creek, located in northwest Alabama and northeast Mississippi, has seen changes to its fauna, possibly the result of impoundment, channelization, wastewater discharge, and sedimentation from such sources such as strip mining, agriculture, and silviculture. The most obvious influences have been impoundment of the lowermost 32 km of Bear Creek by Pickwick Reservoir of Tennessee River, the construction of four dams within the system, construction of a 29-km-long channel designed to limit flooding, and bank destabilization. Mussels are absent from much of the system and faunal composition has apparently been altered where mussels persist, based on comparison to limited previous studies. The most notable changes are the loss of Cumberlandian species diversity and the apparent increase in Ohioan species diversity. We sampled 40 stations in the Bear Creek system and report 32 mussel species live or fresh dead, including 3 Cumberlandian species, and 2 others weathered dead. Fourteen of these species were not reported in two earlier studies. During this study the most depauperate populations were upstream of Bear Creek km 41.0 and in tributaries. No mussels were collected immediately downstream of dams, and diversity gradually increased downstream from the lowermost main channel dam until 28 species occurred together in a free-flowing reach shortly before entering Pickwick Reservoir. One weathered dead zebra mussel, Dreisenna polymorpha, was also collected, representing a new tributary record. The population of Epioblasma brevidens in Bear Creek is the only population of that species known in the lower Tennessee River system, and the population of Lexingtonia dolabelloides, another new tributary record, is one of only two populations of that species known downstream of Paint Rock River.

  12. Analysis of EST and lectin expressions in hemocytes of Manila clams (Ruditapes philippinarum) (Bivalvia: Mollusca) infected with Perkinsus olseni.

    PubMed

    Kang, Yoon-Suk; Kim, Young-Mee; Park, Kyung-Il; Kim Cho, Somi; Choi, Kwang-Sik; Cho, Moonjae

    2006-01-01

    The hemocytes of invertebrates play key roles in both cellular and humoral immune reactions by phagocytosis or delivering immune factors such as lectin and anti-microbial peptides. Bacterial infection causes changes in components such as lectins, anti-bacterial peptides, and lysosomal enzymes of plasma or hemolymph in molluscs. Previously, we found that infection with the protozoan parasite, Perkinsus, increases lectin synthesis in hemocytes. In order to investigate the patterns of genes expressed in Manila clams (Ruditapes philippinarum) infected with the protozoan parasite Perkinsus olseni, we constructed a cDNA library and sequenced 1850 clones (expressed sequence tags). A total of 79 ESTs, were related to 29 functional immune genes such as C-type lectin, lysozyme, and cystatin B, in Manila clams. Lectins were the largest group of immune-function ESTs found in our Manila clams library. Among 7 lectin clones, two full length cDNAs of lectins were cloned. MCL-3, which is a simple C-type lectin composed of 151 amino acids, has a relatively short signal sequence of 17aa and single carbohydrate-recognition domain (CRD) of approximately 130 residues. It is highly homologous to eel C-type lectin. The sequence of mc-sialic acid-binding lectin consists of 168 amino acid residues with molecular weight of 19.2 and shows high homology to sialic acid-binding lectin from the snail, Cepaea hortensis. The expression of 7 different lectins in hemocytes was analyzed by RT-PCR using gene-specific primers. Hemocytes from Perkinsus-infected clam expressed different sets of lectins than with Vibrio infection. These results demonstrate that several lectins are involved in Manila clam innate immunity and different challenges induce expression of different lectins.

  13. Coexistence of Multiple Proteobacterial Endosymbionts in the Gills of the Wood-Boring Bivalve Lyrodus pedicellatus (Bivalvia: Teredinidae)

    PubMed Central

    Distel, Daniel L.; Beaudoin, David J.; Morrill, Wendy

    2002-01-01

    Wood-boring bivalves of the family Teredinidae (commonly called shipworms) are known to harbor dense populations of gram-negative bacteria within specialized cells (bacteriocytes) in their gills. These symbionts are thought to provide enzymes, e.g., cellulase and dinitrogenase, which assist the host in utilizing wood as a primary food source. A cellulolytic, dinitrogen-fixing bacterium, Teredinibacter turnerae, has been isolated from the gill tissues of numerous teredinid bivalves and has been proposed to constitute the sole or predominant symbiont of this bivalve family. Here we demonstrate that one teredinid species, Lyrodus pedicellatus, contains at least four distinct bacterial 16S rRNA types within its gill bacteriocytes, one of which is identical to that of T. turnerae. Phylogenetic analyses indicate that the three newly detected ribotypes are derived from gamma proteobacteria that are related to but distinct (>6.5% sequence divergence) from T. turnerae. In situ hybridizations with 16S rRNA-directed probes demonstrated that the pattern of occurrence of symbiont ribotypes within bacteriocytes was predictable and specific, with some bacteriocytes containing two symbiont ribotypes. However, only two of the six possible pairwise combinations of the four ribotypes were observed to cooccur within the same host cells. The results presented here are consistent with the existence of a complex multiple symbiosis in this shipworm species. PMID:12450854

  14. Numerical Quantification of Perkinsus Marinus in the American Oyster Crassostrea virginicata (Gmelin 1791) (Mollusca: Bivalvia) by Modern Stereology

    EPA Science Inventory

    Species of Perkinsus are responsible for high mortalities of bivalve molluscs world-wide. Techniques to accurately estimate parasites in tissues are required to improve understanding of perkinsosis. This study quantifies the number and tissue distribution of Perkinsus marinus in ...

  15. Early replication dynamics of sex-linked mitochondrial DNAs in the doubly uniparental inheritance species Ruditapes philippinarum (Bivalvia Veneridae)

    PubMed Central

    Guerra, D; Ghiselli, F; Milani, L; Breton, S; Passamonti, M

    2016-01-01

    Mitochondrial homoplasmy, which is maintained by strictly maternal inheritance and a series of bottlenecks, is thought to be an adaptive condition for metazoans. Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial transmission found in bivalve species, in which two distinct mitochondrial genome (mtDNA) lines are present, one inherited through eggs (F) and one through sperm (M). During development, the two lines segregate in a sex- and tissue-specific manner: females lose M during embryogenesis, whereas males actively segregate it in the germ line. These two pivotal events are still poorly characterized. Here we investigated mtDNA replication dynamics during embryogenesis and pre-adulthood of the venerid Ruditapes philippinarum using real-time quantitative PCR. We found that both mtDNAs do not detectably replicate during early embryogenesis, and that the M line might be lost from females around 24 h of age. A rise in mtDNA copy number was observed before the first reproductive season in both sexes, with the M mitochondrial genome replicating more than the F in males, and we associate these boosts to the early phase of gonad production. As evidence indicates that DUI relies on the same molecular machine of mitochondrial maternal inheritance that is common in most animals, our data are relevant not only to DUI but also to shed light on how differential segregations of mtDNA variants, in the same nuclear background, may be controlled during development. PMID:26626575

  16. Mitogenomics of southern hemisphere blue mussels (Bivalvia: Pteriomorphia): Insights into the evolutionary characteristics of the Mytilus edulis complex

    PubMed Central

    Gaitán-Espitia, Juan Diego; Quintero-Galvis, Julian F.; Mesas, Andres; D’Elía, Guillermo

    2016-01-01

    Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere (M. trossulus, M. edulis, M. galloprovincialis, M. californianus and M. coruscus) and three in the Southern Hemisphere (M. galloprovincialis, M. chilensis and M. platensis). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another from the Pacific M. chilensis. These mitogenomes exhibited similar architecture to those of other genomes of Mytilus, including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic divergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species. PMID:27241855

  17. Isolation and characterization of the first microsatellite markers for the endangered relict mussel Hypanis colorata (Mollusca: Bivalvia: Cardiidae).

    PubMed

    Popa, Oana Paula; Iorgu, Elena Iulia; Krapal, Ana Maria; Kelemen, Beatrice Simona; Murariu, Dumitru; Popa, Luis Ovidiu

    2011-01-17

    Hypanis colorata (Eichwald, 1829) (Cardiidae: Lymnocardiinae) is a bivalve relict species with a Ponto-Caspian distribution and is under strict protection in Romania, according to national regulations. While the species is depressed in the western Black Sea lagoons from Romania and Ukraine, it is also a successful invader in the middle Dniepr and Volga regions. Establishing a conservation strategy for this species or studying its invasion process requires knowledge about the genetic structure of the species populations. We have isolated and characterized nine polymorphic microsatellite markers in H. colorata. The number of alleles per locus ranged from 4 to 28 and the observed heterozygosity ranged from 0.613 to 1.000. The microsatellites developed in the present study are highly polymorphic and they should be useful for the assessment of genetic variation within this species.

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

    NASA Astrophysics Data System (ADS)

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

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

  19. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae).

    PubMed

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population.

  20. High-resolution elemental records of Glycymeris glycymeris (Bivalvia) shells from the Iberian upwelling system: Ontogeny and environmental control

    NASA Astrophysics Data System (ADS)

    Freitas, Pedro; Richardson, Christopher; Chenery, Simon; Butler, Paul; Reynolds, David; Gaspar, Miguel; Scourse, James

    2015-04-01

    The great potential of bivalve shells as a high-resolution geochemical proxy archive of environmental conditions at the time of growth has been known for several decades. The elemental composition of bivalve shells has been studied with the purpose of reconstructing environmental conditions: e.g. seawater temperature (Sr and Mg), primary productivity (Li, Mn, Mo and Ba), redox conditions (Mn and Mo), terrigenous inputs (Li) and pollution (Cu, Zn, Cd and Pb). However, the interpretation of such records remains extremely challenging and complex, with processes affecting element incorporation in the shell (e.g. crystal fabrics, organic matrix, shell formation mechanisms and physiological processes) and the influence of more than one environmental parameter affecting elemental composition of bivalve shells. Nevertheless, bivalve shells remain an underused source of information on environmental conditions, with the potential to record high-resolution (sub-weekly to annually), multi-centennial time series of geochemical proxy data. The relatively long-lived bivalve (>100 years) Glycymeris glycymeris occurs in coastal shelf seas of Europe and North West Africa and is a valid annually resolved sclerochronological archive for palaeonvironmental reconstructions. The temporal framework provided by absolute annually dated shell material makes Glycymeris glycymeris a valuable, albeit unexplored, resource for investigating sub-annually resolved geochemical proxies. We present a first evaluation on the potential of Ba, P and U, the latter two elements rarely studied in bivalves, in Glycymeris glycymeris shells to record variations in the environmental conditions, respectively primary productivity, dissolved inorganic phosphorus and carbonate ion concentration/pH. High-resolution (31 to 77 samples per year) profiles of elemental/Ca ratios (E/Ca) over four years of growth (2001 to 2004) were obtained by LA-ICP-MS on two shells (13 and 16 years old) live-collected in 2010 at 30 m water depth on the Iberia upwelling system. In both shells, clear E/Ca annual cycles with significant higher-frequency variability (weekly to sub-monthly) were observed over the four years of growth analysed. However, E/Ca ratios and the amplitude of the annual E/Ca cycles were lower in the older shell and showed decreasing trends with age (ontogenetic effects). E/Ca ratios were age-detrended using statistical techniques derived from dendrochronology, resulting in similar and coherent profiles in both shells. It seems unlikely that enough variability in E/Ca ratios will be recorded in the shell after 15 to 20 years of age to allow the retrieval of an environmental signal by age-detrending E/Ca ratios. Detrended P/Ca, Ba/Ca and U/Ca in Glycymeris glycymeris shells showed coherent variations with coeval modelled and instrumental oceanographic series from the Iberia upwelling system that suggest a robust potential as an archive of environmental conditions in the first 15 to 20 years of growth. Nevertheless a robust calibration is required to distinguish between the influences of multiple environmental parameters. This study was financed and conducted in the frame of the Portuguese FCT GLYCY Project (contract PTDC/AAC-CLI/118003/2010).

  1. Metal sources to the Baltic clam Macoma balthica (Mollusca: Bivalvia) in the southern Baltic Sea (the Gulf of Gdansk).

    PubMed

    Sokolowski, Adam; Wolowicz, Maciej; Hummel, Herman

    2007-04-01

    Metal concentrations of Cu, Fe, Mn, Ni, Pb and Zn in an infaunal facultative deposit-feeding bivalve, the Baltic clam Macoma balthica, in the Gulf of Gdansk (southern Baltic Sea) were assessed and compared to selected concentrations of metals in the environment. Between October 1996 and September 1997, dissolved and easy extractable (by 1M HCl) metal fractions of total suspended particulate matter (TPM) in the overlying water and of surficial sediments (<63 microm) were measured monthly at five sublittoral sites in the Gulf of Gdansk, and accumulated tissue metal concentrations in M. balthica were determined simultaneously. The study highlights the importance of sediment geochemistry as a factor modifying ambient trace metal bioavailabilities. Surficial sediments appeared to contribute most to the accumulation of Cu and Pb in M. balthica, reflecting the high metal availability in the Gulf. Assimilation of Cu from sediments is controlled by Mn components possibly through an inhibitory effect of Mn oxyhydroxides, while Pb accumulation from sediments depends on the organic content of the sediment. A dual metal uptake pathway, with a suspended particulate-bound fraction and surficial sediments, was apparent for Mn and Zn. Partitioning of Mn in sediments was related to the concentration of labile Fe, with increased levels of Fe tending to inhibit the accumulation of Mn by the clam. Tissue accumulated Zn might have been altered by the clam's internal regulation, making Zn tissue concentrations, to some degree, independent of its environmental level. The principal source of Ni accumulated by the clams exists in the soluble phase.

  2. Lack of bioaccumulation of metals by Elliptio complanata (Bivalvia) during acidic snowmelt in three south-central Ontario streams

    SciTech Connect

    Servos, M.R.; Malley, D.F.; Mackie, G.L.; LaZerte, B.D.

    1987-05-01

    Depression of pH and elevation of metals during spring snowmelt may be widespread. However, because of the episodic nature of these events they are very difficult to measure or even detect. Sampling of snowmelt at regular intervals of only a few days, may not be adequate to detect short-term variations in pH and metal concentrations. The objective of the present study was to determine the feasibility of using biomonitoring to detect short-term changes in concentration or bioavailability of metals (Al, Zn, Cd) during spring snowmelt. Unionid clams, (Elliptio complanata) were held in three south-central Ontario streams during the spring snowmelt period of 1982. The gill tissues accumulate metals more readily than other tissues and thus are better biomonitors of available metals than whole body concentrations of these elements. Therefore, the concentration of metals in soft tissues (gill, body, foot) were compared separately to the stream water chemistry during snowmelt.

  3. Reproductive biology of four freshwater mussels (Bivalvia: Unionidae) endemic to eastern Gulf Coastal Plain drainages of Alabama, Florida, and Georgia

    USGS Publications Warehouse

    O'Brien, C. A.; Williams, J.D.

    2002-01-01

    The reproductive biology and glochidial shell morphology of three federally endangered freshwater mussels, the fat threeridge, Amblema neislerii; Gulf moccasinshell, Medionidus penicillatus; and oval pigtoe, Pleurobema pyriforme; and one federally threatened mussel, the purple bankclimber, Elliptoideus sloatianus, were studied from May 1995 to June 1997 in the Apalachicola, Flint, and Ochlockonee river drainages of Florida and Georgia. Gravid A. neislerii were found in early June. Laboratory experiments indicated that five fish species served as hosts: weed shiner, Notropis texanus; bluegill, Lepomis macrochirus; redear sunfish, L. microlophus; largemouth bass, Micropterus salmoides; and blackbanded darter, Percina nigrofasciata. Elliptoideus sloatianus were found gravid from late February through mid-April. None of the 14 fish species exposed to E. sloatianus glochidia resulted in the identification of a primary host fish. Medionidus penicillatus were found gravid during September, November, March, and April. The brown darter, Etheostoma edwini, and blackbanded darter, Percina nigrofasciata, were identified as primary host fishes for M. penicillatus. Pleurobema pyriforme were found gravid from March through July. Only the sailfin shiner, Pleronotropis hypsehpterus, was identified as a primary host fish for P. pyriforme. Glochidial shell morphology of A. neislerii, M. penicillatus, and P. pyriforme were similar to other species in their respective genera. The glochidia of the monotypic species E. sloatianus were morphologically most similar to Epioblasma brevidens and E. capsaeformis.

  4. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae)

    PubMed Central

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R.

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population. PMID:26745804

  5. Phage particles infecting branchial Rickettsiales-like organisms in banded carpet shell Polititapes virgineus (Bivalvia) from Galicia (NW Spain).

    PubMed

    Darriba, S; Ruiz, M; López, C

    2012-09-12

    Basophilic intracellular prokaryotic-like colonies were observed in the gills of banded carpet shell Polititapes virgineus (= Tapes rhomboides) (Linnaeus, 1767) from a natural bed in Galicia (NW Spain). Light microscope observations suggested the presence of 2 types of colonies, but transmission electron microscopy revealed that these were the same Rickettsiales-like colonies, one infected and the other uninfected by phage particles. This is the first report of the presence of phage particles in Rickettsiales-like organisms in the gills of P. virgineus.

  6. Phylogeny of the most species-rich freshwater bivalve family (Bivalvia: Unionida: Unionidae): Defining modern subfamilies and tribes.

    PubMed

    Lopes-Lima, Manuel; Froufe, Elsa; Do, Van Tu; Ghamizi, Mohamed; Mock, Karen E; Kebapçı, Ümit; Klishko, Olga; Kovitvadhi, Satit; Kovitvadhi, Uthaiwan; Paulo, Octávio S; Pfeiffer, John M; Raley, Morgan; Riccardi, Nicoletta; Şereflişan, Hülya; Sousa, Ronaldo; Teixeira, Amílcar; Varandas, Simone; Wu, Xiaoping; Zanatta, David T; Zieritz, Alexandra; Bogan, Arthur E

    2017-01-01

    Freshwater mussels of the order Unionida are key elements of freshwater habitats and are responsible for important ecological functions and services. Unfortunately, these bivalves are among the most threatened freshwater taxa in the world. However, conservation planning and management are hindered by taxonomic problems and a lack of detailed ecological data. This highlights the urgent need for advances in the areas of systematics and evolutionary relationships within the Unionida. This study presents the most comprehensive phylogeny to date of the larger Unionida family, i.e., the Unionidae. The phylogeny is based on a combined dataset of 1032bp (COI+28S) of 70 species in 46 genera, with 7 of this genera being sequenced for the first time. The resulting phylogeny divided the Unionidae into 6 supported subfamilies and 18 tribes, three of which are here named for the first time (i.e., Chamberlainiini nomen novum, Cristariini nomen novum and Lanceolariini nomen novum). Molecular analyses were complemented by investigations of selected morphological, anatomical and behavioral characters used in traditional phylogenetic studies. No single morphological, anatomical or behavioral character was diagnostic at the subfamily level and few were useful at the tribe level. However, within subfamilies, many tribes can be recognized based on a subset of these characters. The geographical distribution of each of the subfamilies and tribes is also presented. The present study provides important advances in the systematics of these extraordinary taxa with implications for future ecological and conservation studies.

  7. Early replication dynamics of sex-linked mitochondrial DNAs in the doubly uniparental inheritance species Ruditapes philippinarum (Bivalvia Veneridae).

    PubMed

    Guerra, D; Ghiselli, F; Milani, L; Breton, S; Passamonti, M

    2016-03-01

    Mitochondrial homoplasmy, which is maintained by strictly maternal inheritance and a series of bottlenecks, is thought to be an adaptive condition for metazoans. Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial transmission found in bivalve species, in which two distinct mitochondrial genome (mtDNA) lines are present, one inherited through eggs (F) and one through sperm (M). During development, the two lines segregate in a sex- and tissue-specific manner: females lose M during embryogenesis, whereas males actively segregate it in the germ line. These two pivotal events are still poorly characterized. Here we investigated mtDNA replication dynamics during embryogenesis and pre-adulthood of the venerid Ruditapes philippinarum using real-time quantitative PCR. We found that both mtDNAs do not detectably replicate during early embryogenesis, and that the M line might be lost from females around 24 h of age. A rise in mtDNA copy number was observed before the first reproductive season in both sexes, with the M mitochondrial genome replicating more than the F in males, and we associate these boosts to the early phase of gonad production. As evidence indicates that DUI relies on the same molecular machine of mitochondrial maternal inheritance that is common in most animals, our data are relevant not only to DUI but also to shed light on how differential segregations of mtDNA variants, in the same nuclear background, may be controlled during development.

  8. Reproductive biology and juvenile recruitment of the shinyrayed pocketbook, Lampsilis subangulata (Bivalvia: Unionidae) in the Gulf Coastal Plain

    USGS Publications Warehouse

    O'Brien, C. A.; Brim-Box, J.

    1999-01-01

    The reproductive biology, glochidial morphology and recruitment of the federally endangered shinyrayed pocketbook, Lampsilis subangulata, were studied from May 1995 to July 1996 in the Flint River system, Georgia. Gravid female L. subangulata were found nine months of the year. On 19 May 1995, a L. subangulata was discovered releasing a superconglutinate, the first record confirming that this species used this specialized reproductive strategy. Superconglutinate release occurred from late May to mid-July in water temperatures ranging from 20.0 to 23.5 C. Laboratory experiments indicated that two fish species served as primary hosts, the spotted bass (Micropterus punctulatus) and largemouth bass (M. salmoides). Secondary host fish included the eastern mosquitofish (Gambusia holbrooki), guppy (Poecilia reticulata) and bluegill (Lepomis macrochirus). The glochidial morphology of L. subangulata was similar to other lampsiline species. Using quantitative survey methods, no evidence of recent juvenile recruitment was found in the largest known extant L. subangulata population.

  9. New lucinid bivalves from shallow and deeper water of the Indian and West Pacific Oceans (Mollusca, Bivalvia, Lucinidae)

    PubMed Central

    Taylor, John D.; Glover, Emily A.

    2013-01-01

    Abstract Four new species and a new genus of lucinid bivalves are described from shallow and deeper waters in the Indian and West Pacific Oceans. The new genus Scabrilucina (subfamily Lucininae) includes the little-known Scabrilucina victorialis (Melvill, 1899) from the Arabian Sea and Scabrilucina vitrea (Deshayes, 1844) from the Andaman Sea as well as a new species Scabrilucina melvilli from the Torres Strait off northeastern Australia. Ferrocina brunei new species (Lucininae) was recovered from 60 m near oil drilling activities off Borneo; its anatomy confirmed the presence of symbiotic bacteria. Two unusual deeper water species of Leucosphaerinae are described, both species included in on-going molecular analyses; Gonimyrtea ferruginea from 400–650 m in the southwest Pacific and Myrtina reflexa from 200–825 m off Zanzibar and Madagascar. PMID:24039537

  10. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae) (Müller, 1774) in Portugal

    PubMed Central

    Gomes, Cidália; Sousa, Ronaldo; Mendes, Tito; Borges, Rui; Vilares, Pedro; Vasconcelos, Vitor; Guilhermino, Lúcia; Antunes, Agostinho

    2016-01-01

    The Asian clam, Corbicula fluminea, is an invasive alien species (IAS) originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers), morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River) and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity. PMID:27391333

  11. Patterns of species richness among assemblages of Unionicola spp. (Acari: Unionicolidae) inhabiting freshwater mussels (Bivalvia: Unionoida) of North America.

    PubMed

    Edwards, Dale D; Vidrine, Malcolm F

    2013-04-01

    Water mites of Unionicola species are common symbionts of freshwater mussels, living on the gills or mantle and foot of their hosts and using these tissues as sites of oviposition. Although surveys of the mite fauna among North American mussels suggest that these mites represent highly diverse assemblages, there are currently no quantitative data characterizing Unionicola species diversity among their molluscan hosts. The present study addresses patterns of species richness of Unionicola assemblages from freshwater mussels, including the relationship between richness and host specificity among these mites. Results from this study indicate that mite species richness increased significantly with an increase in the number of host individuals sampled. When corrected for sampling effort, there was a positive relationship between host size and mite species richness. Results from this study also reveal a significant relationship between mite species richness and the geographical distribution of host mussels. Overall, the patterns of species richness observed for this study are consistent with those examining the richness of parasitic helminth communities. Because the phylogenetic history of host taxa can have a significant influence on patterns of parasite species richness, studies that correct for the phylogenetic history among host mussels will be required to better understand the role that evolutionary processes have in determining Unionicola species richness. The present study did not indicate a significant relationship between species richness and host specificity and, in not doing so, suggests that the dispersal ability of mites may also play a role in influencing Unionicola species richness. The host recognition behavior and swimming abilities for a larger sample of mites will be required to substantiate this hypothesis.

  12. Gas Hydrate Exploration, Mid Chilean Coast; Geochemical-Geophysical Survey

    DTIC Science & Technology

    2006-12-27

    Scleractinia - - - - - - - - Nemertinea - - Mollusca Bivalvia + - + - - ++ + - + - + - Aplacophora...Caelorinchus fasciatus and three unknow species) were observed. In addition, fauna inside stones was found ( Mollusca : Leptochiton americanus

  13. [Non detection of enterovirus in the bivalve Anadara tuberculosa (Bivalvia:Arcidae) caused by chemical contamination in the Pacific of Costa Rica].

    PubMed

    Libia Herrero, U; Alejandro Palacios, F; Laya Hun, O; Francisco Vega, A

    1999-09-01

    Anadara tuberculosa is one of the most abundant mollusks of commercial importance in Costa Rica. Its habitat water is a potential source of fecal and chemical contamination to humans. We wanted to asses enterovirus, mainly poliovirus and hepatitis A virus and chemicals such as sulphates and nitrates in meat and body fluids. Thirteen samples were taken from four sites in Nicoya Gulf, three sites in the Sierpe-Térraba mangrove (Pacific of Costa Rica) and from five fish markets in San José, the capital of Costa Rica. Samples were tested for 1) fecal coliforms (Most Probable Number/100 ml), 2) isolation of enterovirus in cell culture (Hep-2, FrhK-4), 3) cell cytotoxicity in Vero cells and 4) the ability to inactivate 10 ID50% of poliovirus in cell culture. The Most Probable Number/100 ml in surrounding water was higher than the accepted standard for recreational waters, although the number of fecal coliforms in meats and body fluids was lower than in the external water. No cytopathogenic agents were isolated, but we found nitrate and sulphate concentrations that exceeded maxima for human consumption and recreation. The intrinsic cytotoxicity of the samples was at a 1/8 dilution, but some samples were cytotoxic at dilutions of 1/128. Body fluids were more cytotoxic than meats, but a positive correlation between cytotoxicity and chemical contamination was not determined: apparently other pollutants not identified in this study were responsible. Fluid and meat capacity to inactivate 10 ID50% of poliovirus in cell culture was demonstrated. Samples that were toxic for cell cultures also showed a higher percentage of poliovirus inactivation. Monitoring chemical pollution in these waters is highly recommended.

  14. Prevalence of a protozoan parasite Cristigera sp. (Ciliophora:Ciliatea) from edible oysters (Mollusca:Bivalvia) of Sundarbans, West Bengal, India.

    PubMed

    Biswas, Tanima; Bandyopadhyay, Probir Kumar

    2014-09-01

    The coastal region of West Bengal is bestowed with a wide range of natural forest and aquatic resources. The estuarine complex is a culmination of the interaction of land, sea and freshwater. It offers diverse specialised habitats such as mangroves, non vegetated mudflats, inter tidal zones and reclaimed areas. Such areas are home to a number of terrestrial, freshwater and marine communities. Edible oyster resources in these regions are Crassostrea gryphoides and Saccostrea cucullata, which are the keystone species found in the intertidal zone and can tolerate huge variation of salinity. These are used as food by local people and marketed to earn cash. The population of this species has been declined due to parasitic infection and pollution. There are many protozoan parasites which infect these oysters causing diseases. During survey period, a protozoan parasite of the genus Cristigera have been observed only from the edible oyster Crassostrea gryphoides collected from Kaikhali and Frasergunj among three selected sites namely Kaikhali, Frasergunj and Digha of West Bengal mainly during monsoon and post-monsoon season. Considering such rare and specific prevalence of Cristigera sp, it may be considered as potential bio-indicator.

  15. Molecular characterization and expression of a novel homolog of uncoupling protein 5 (UCP5) from the eastern oyster Crassostrea virginica (Bivalvia: Ostreidae).

    PubMed

    Kern, Britt; Ivanina, Anna V; Piontkivska, Helen; Sokolov, Eugene P; Sokolova, Inna M

    2009-06-01

    Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier gene family which has been implicated in diverse physiological functions ranging from thermoregulation to antioxidant defense. In mammals, the UCP family is well characterized and contains five members (UCP1-5). In contrast, invertebrate homologues of uncoupling proteins are much less studied both from the viewpoints of structure and function. In this study we report nucleotide and predicted protein structure of an important member of UCP family, UCP5 from eastern oysters Crassostrea virginica. UCP5 from oysters appears to be a close homolog of the mammalian brain mitochondrial carrier protein (BMCP1, or UCP5) and is the first full-length UCP described from a Lophotrochozoan invertebrate. Evolutionary analysis of UCP sequences indicates at least three monophyletic UCP branches (UCP1-3, UCP4 and UCP5) that have diverged early in the evolution, prior to the divergence of vertebrates and invertebrates. In oysters, two forms of UCP5 transcript are found (UCP5S and UCP5L) that differ by 152 bp in length due to the presence of an intron in UCP5L. UCP5 was expressed in all studied oyster tissues, unlike mammals, where UCP5 is predominantly expressed in brains and male gonads. Hypoxia-reoxygenation stress, sublethal Cd exposure (50 ?g L(?1) Cd for 56 days) and acclimation to different temperatures (12 and 20 °C) had no significant effect on UCP5 mRNA expression in oysters indicative of its relative unimportance in antioxidant defense and temperature adaptation of oyster mitochondria. These data suggest that despite the relatively high degree of evolutionary conservation of the UCP5 amino acid sequence, its functional significance in mitochondria changed in the course of evolution of mollusks and vertebrates.

  16. A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the oyster mussel Epioblasma capsaeformis and tan riffleshell Epioblasma florentina walkeri (Bivalvia: Unionidae)

    USGS Publications Warehouse

    Jones, J.W.; Neves, R.J.; Ahlstedt, S.A.; Hallerman, E.M.

    2006-01-01

    Species in the genus Epioblasma have specialized life history requirements and represent the most endangered genus of freshwater mussels (Unionidae) in the world. A genetic characterization of extant populations of the oyster mussel E. capsaeformis and tan riffleshell E. florentina walkeri sensu late was conducted to assess taxonomic validity and to resolve conservation issues for recovery planning. These mussel species exhibit pronounced phenotypic variation, but were difficult to characterize phylogenetically using DNA sequences. Monophyletic lineages, congruent with phenotypic variation among species, were obtained only after extensive analysis of combined mitochondrial (1396 bp of 16S, cytochrome-b, and ND1) and nuclear (515 bp of ITS-1) DNA sequences. In contrast, analysis of variation at 10 hypervariable DNA microsatellite loci showed moderately to highly diverged populations based on FST and R ST values, which ranged from 0.12 to 0.39 and 0.15 to 0.71, respectively. Quantitative variation between species was observed in fish-host specificity, with transformation success of glochidia of E. capsaeformis significantly greater (P<0.05) on greenside darter Etheostoma blennioides, and that of E. f. walkeri significantly greater (P<0.05) on fantail darter Etheostoma flabellare. Lengths of glochidia differed significantly (P<0.001) among species and populations, with mean sizes ranging from 241 to 272 ??m. The texture and colour of the mantle-pad of E. capsaeformis sensu stricto is smooth and bluish-white, whereas that of E. f. walkeri is pustuled and brown, with tan mottling. Based on extensive molecular, morphological and life history data, the population of E. capsaeformis from the Duck River, Tennessee, USA is proposed as a separate species, and the population of E. f. walkeri from Indian Creek, upper Clinch River, Virginia, USA is proposed as a distinct subspecies.

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

    PubMed

    Sokolova, Inna M; Sokolov, Eugene P; Ponnappa, Kavita M

    2005-07-01

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

  18. Morphological and Genetic Diversity of the Wood-Boring Xylophaga (Mollusca, Bivalvia): New Species and Records from Deep-Sea Iberian Canyons

    PubMed Central

    Romano, Chiara; Voight, Janet Ruth; Pérez-Portela, Rocío; Martin, Daniel

    2014-01-01

    Deep-sea bivalves of the Xylophagaidae, a poorly known group, are obligate wood-borers. Deployment of wood in three submarine canyons off the Iberian coast, the Blanes and La Fonera Canyons (Mediterranean Sea) and the Avilés Canyon (Cantabric Sea, Bay of Biscay), lead to the discovery of four xylophagaid species in our samples. Xylophaga dorsalis (the dominant species), X. atlantica, X. cf. anselli and the new species X. brava, were identified on the basis of morphological data, and supported by a phylogenetic reconstruction based on the nuclear genes 18S rDNA and 28S rDNA and including several genus of Xylophagaidae. Genetic divergence between species of Xylophaga varied between genes, ranging from 0.5 to 4.0% for the 18SrDNA and from 4.1 to 16.6% for the 28SrDNA. Xylophaga brava sp. nov. appeared to be restricted to the Mediterranean and morphologically resembled the closely related X. cf. anselli from the Cantabrian Sea. However, they clearly diverged in two well-supported clades. Low levels of intraspecific variability and higher interspecific divergence between species also supported the existence of these two different species. Morphologically they differ in the number of cirri at the siphon openings, in the shape of the posterior shell and in the size of prodissoconch II. The new species is characterized by having weak, poorly mineralized mesoplax and siphons united throughout, covered by a periostracal, non-calcified tube; distinct proximal and distal siphons, the former translucent and soft, the latter muscular, with concentric rings. Xylophaga atlantica, previously known only from the western Atlantic, is reported for the first time in the Mediterranean Sea. Whether its presence in the Mediterranean indicates its natural distribution or reflects its recent introduction is unknown. Although xylophagaids have been previously reported to recruit heavily to wood deposited on the seabed, these four species colonized wood suspended 30 m above the seafloor. PMID:25061913

  19. Dreissena polymorpha (Bivalvia: Dreissenidae) in the Neva Estuary (eastern Gulf of Finland, Baltic Sea): is it a biofilter or source for pollution?

    PubMed

    Orlova, M; Golubkov, S; Kalinina, L; Ignatieva, N

    2004-08-01

    The zebra mussel Dreissena polymorpha, a ponto-caspian byssate bivalve, forms permanent dense populations along the shoreline in the northern part of the inner Neva Estuary. Its total biomass along a 17 km transect reached 4980 tons (mean 1060 g m(-2)) in 2000 and 6510 tons (mean 1385 g m(-2)) in 2001. Being persistent and abundant, the zebra mussel populations played an important role in benthic-pelagic coupling in inner Neva River Estuary. The D. polymorpha population released up to 514 kg day(-1) of dissolved inorganic phosphorus and was, therefore, a major source of bioavailable nutrients in the area. Mussel beds were also efficient biofilters and precipitate 15,020 kg day(-1) of particulate organic matter during the warm season. About 50% of precipitated matter had a relatively long retention time, being utilized within zebra mussel populations, while the rest was deposited as faeces and pseudofaeces and served as a source for organic pollution to the eastern Gulf of Finland.

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

    PubMed

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

    2014-06-01

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

  1. The genome of the Pacific oyster Crassostrea gigas brings new insights on the massive expansion of the C1q gene family in Bivalvia.

    PubMed

    Gerdol, Marco; Venier, Paola; Pallavicini, Alberto

    2015-03-01

    C1q domain-containing (C1qDC) proteins are regarded as important players in the innate immunity of bivalve mollusks and other invertebrates and their highly adaptive binding properties indicate them as efficient pathogen recognition molecules. Although experimental studies support this view, the molecular data available at the present time are not sufficient to fully explain the great molecular diversification of this family, present in bivalves with hundreds of C1q coding genes. Taking advantage of the fully sequenced genome of the Pacific oyster Crassostrea gigas and more than 100 transcriptomic datasets, we: (i) re-annotated the oyster C1qDC loci, thus identifying the correct genomic organization of 337 C1qDC genes, (ii) explored the expression pattern of oyster C1qDC genes in diverse developmental stages and adult tissues of unchallenged and experimentally treated animals; (iii) investigated the expansion of the C1qDC gene family in all major bivalve subclasses. Overall, we provide a broad description of the functionally relevant features of oyster C1qDC genes, their comparative expression levels and new evidence confirming that a gene family expansion event has occurred during the course of Bivalve evolution, leading to the diversification of hundreds of different C1qDC genes in both the Pteriomorphia and Heterodonta subclasses.

  2. Sex-linked mitochondrial behavior during early embryo development in Ruditapes philippinarum (Bivalvia Veneridae) a species with the Doubly Uniparental Inheritance (DUI) of mitochondria.

    PubMed

    Milani, Liliana; Ghiselli, Fabrizio; Passamonti, Marco

    2012-05-01

    In most metazoans mitochondria are inherited maternally. However, in some bivalve molluscs, two mitochondrial lineages are present: one transmitted through females (F-type), the other through males (M-type). This unique system is called Doubly Uniparental Inheritance (DUI) of mitochondria. In DUI species, M-type mitochondria have to invade the germ line of male embryos during development, otherwise sperm would transmit F-type mtDNA and DUI would fail. The mechanisms by which sperm mitochondria enter the germ line are still unknown. To address this question, we traced the movement of spermatozoon mitochondria (M-type) in embryos of the DUI species Ruditapes philippinarum by fertilizing eggs with sperm stained with the mitochondrial-specific vital dye MitoTracker Green. As in Mytilus DUI species, in R. philippinarum the distribution of sperm mitochondria follows two different patterns: an aggregated one in which these organelles locate near the first cleavage furrow, and a dispersed one in which sperm mitochondria are scattered. The presence of the two mitochondrial patterns in these taxa, together with their absence in species with Strictly Maternal Inheritance (SMI), confirms that their occurrence is related to DUI. Moreover, a Real-Time qPCR analysis showed that neither M-type nor F-type mitochondria undergo replication boosts in the earliest embryo development. This is the first study on sex-linked mtDNA copy number carried out by qPCR analysis on embryos of a DUI species and the first time the segregation patterns of sperm mitochondria are described in a DUI system other than Mytilus.

  3. Survival of glochidial larvae of the freshwater pearl mussel, Margaritifera laevis (Bivalvia: Unionoida), at different temperatures: a comparison between two populations with and without recruitment.

    PubMed

    Akiyama, Yoshihiro; Iwakuma, Toshio

    2007-09-01

    The viability of free-living glochidia of the freshwater pearl mussel (Margaritifera laevis) was studied in the laboratory at water temperatures of 10 degrees C, 15 degrees C and 20 degrees C. To obtain glochidia, gravid female mussels were collected from the Chitose River, inhabited by adult and juvenile mussels, and from the Abira River, where only adult mussels were found. Daily survival rates of glochidia from each population at various water temperatures were significantly different, and survival time was longest at the lowest temperature in each population. Maintenance of some field mussel populations might become difficult at higher water temperatures due to the short survival time of glochidia and expected low density of host fish. Daily survival rates of glochidia were compared between the Abira population at 15 degrees C and the Chitose population at 20 degrees C, since these temperatures were close to the mean water temperature during the period of glochidial release in the respective rivers. Daily mean survival rates were significantly different between the Abira population at 15 degrees C and the Chitose population at 20 degrees C. Mean glochidial survival rate for the Chitose population changed from 85.3% to 66.2% from 9 to 13 h, whereas that for the Abira population dropped suddenly from 80.4% to 34.2% from 10 to 14 h after the initiation of experiment. Absence of juveniles in the Abira River might have been caused by the low glochidial viability. Survival times of free-living glochidia in Margaritiferidae tend to be shorter than in other families in Unionoida. A trade-off is suggested between high fertility and low glochidial survival rate in Margaritiferidae.

  4. Temporal Changes in Gametogenesis of the Invasive Chinese Pond Mussel Sinanodonta woodiana (Lea, 1834) (Bivalvia: Unionidae) from the Konin Lakes System (Central Poland).

    PubMed

    Hliwa, Piotr; Zdanowski, Bogusław; Dietrich, Grzegorz J; Andronowska, Aneta; Król, Jarosław; Ciereszko, Andrzej

    2015-01-01

    Gametogenesis and the temporal changes occurring in the ovaries and testes throughout the reproductive cycle in the invasive alien bivalve, Chinese pond mussel Sinanodonta woodiana (Lea), from the heated Konin lakes system (central Poland) were studied using histological techniques. S. woodiana was confirmed to be a gonochoristic species with overall sex ratio of 1:1. The examined morphological parameters of Chinese pond mussel spermatozoa, i.e. 42 μm mean total length; 4.3 μm mean head length and the maximum size of previtellogenic (34-43 μm) and vitellogenic oocytes (75-83 μm) are consistent with values established for closely related members of the Unionidae family. Our results suggest that S. woodiana in the Konin lakes system are able to spawn throughout March to October, with a season of higher reproductive activity in females extending from March to April. This type of reproductive biology may contribute to the Chinese pond mussel's success in thriving in freshwater ecosystems.

  5. [Effect of excretion-secretion products of some fouling species on the biochemical parameters of blue mussel Mytilus edulis L. (Mollusca: Bivalvia) in the White Sea].

    PubMed

    Skidchenko, V S; Vysotskaia, R U; Krupnova, M Iu; Khalaman, V V

    2011-01-01

    The effect of excretion-secretion products (ESP) of five abundant fouling invertebrate species (bivalve mollusks Hiatella arctica and Mytilus edulis, solitary ascidia Styela rustica, sponge Halichondria panicea, and sea starAsterias rubens, inhabiting the White Sea) on the biochemical status of blue mussel M. edulis was assessed by the dynamics of lysosomal enzymes activity (nucleases, glycoside hydrolases, and cathepsins). ESP of conspecific species had no effect on the metabolism of the mollusks of this species. ESP of A. rubens, S. rustica, and H. panicea activated the same enzymes. First, acid RNase and glycoside hydrolases activity increased, but in different ways. The metabolites of H. arctica affected the activity of proteometabolism enzymes.

  6. Gender-Associated Mitochondrial DNA Heteroplasmy in Somatic Tissues of the Endangered Freshwater Mussel Unio crassus (Bivalvia: Unionidae): Implications for Sex Identification and Phylogeographical Studies.

    PubMed

    Mioduchowska, Monika; Kaczmarczyk, Agnieszka; Zając, Katarzyna; Zając, Tadeusz; Sell, Jerzy

    2016-11-01

    Some bivalve species possess two independent mitochondrial DNA lineages: maternally (F-type) and paternally (M-type) inherited. This phenomenon is called doubly uniparental inheritance. It is generally agreed that F-type mtDNA is typically present in female somatic and gonadal tissues as well as in male somatic tissues, whereas the M-type mtDNA occurs only in male germ line and gonadal tissue. In the present study, the mtDNA heteroplasmy (for both F and M genomes) in male somatic tissues of Unio crassus (Philipsson, 1788), species threatened with extinction, has been confirmed. Taking advantage from the presence of Mcox1 marker only in male somatic tissues, we developed a new method of sex identification in this endangered species, using nondestructive tissue sampling. Probability of correct sex identification was estimated at 97.5%. The present study is the first report on gender-associated mitochondrial DNA heteroplasmy in male somatic tissues of thick-shelled river mussel and first approach to U. crassus sex identification at molecular level. Our study also confirmed the utility of paternally inherited Mcox1 gene fragment as a complementary molecular tool for resolving phylogeographical relationships among populations of thick-shelled river mussel.

  7. Incongruence between mtDNA and nuclear data in the freshwater mussel genus Cyprogenia (Bivalvia: Unionidae) and its impact on species delineation.

    PubMed

    Chong, Jer Pin; Harris, John L; Roe, Kevin J

    2016-04-01

    Accurately identifying species is a crucial step for developing conservation strategies for freshwater mussels, one of the most imperiled faunas in North America. This study uses genetic data to re-examine species delineation in the genus Cyprogenia. Historically, Cyprogenia found west of the Mississippi River have been ascribed to Cyprogenia aberti (Conrad 1850), and those east of the Mississippi River were classified as Cyprogenia stegaria (Rafinesque 1820). Previous studies using mitochondrial DNA sequences indicated that C. aberti and C. stegaria were not reciprocally monophyletic groups, suggesting the need for systematic revision. We generated a novel dataset consisting of 10 microsatellite loci and combined it with sequence data from the mitochondrial ND1 gene for 223 Cyprogenia specimens. Bayesian analysis of the ND1 nucleotide sequences identified two divergent clades that differ by 15.9%. Members of these two clades occur sympatrically across most sampling locations. In contrast, microsatellite genotypes support recognition of three allopatric clusters defined by major hydrologic basins. The divergent mitochondrial lineages are highly correlated with the color of the conglutinate lures used by mussels to attract and infest host fishes, and tests for selection at the ND1 locus were positive. We infer that the incongruence between mtDNA and microsatellite data in Cyprogenia may be the result of a combination of incomplete lineage sorting and balancing selection on lure color. Our results provide further evidence that mitochondrial markers are not always neutral with respect to selection, and highlight the potential problems of relying on a single-locus-marker for delineating species.

  8. Genetic relationships among freshwater mussel species from fifteen Amazonian rivers and inferences on the evolution of the Hyriidae (Mollusca: Bivalvia: Unionida).

    PubMed

    Santos-Neto, Guilherme da Cruz; Beasley, Colin Robert; Schneider, Horacio; Pimpão, Daniel Mansur; Hoeh, Walter Randolph; Simone, Luiz Ricardo Lopes de; Tagliaro, Claudia Helena

    2016-07-01

    The current phylogenetic framework for the South American Hyriidae is solely based on morphological data. However, freshwater bivalve morphology is highly variable due to both genetic and environmental factors. The present study used both mitochondrial (COI and 16S) and nuclear (18S-ITS1) sequences in molecular phylogenetic analyses of nine Neotropical species of Hyriidae, collected from 15 South American rivers, and sequences of hyriids from Australia and New Zealand obtained from GenBank. The present molecular findings support traditional taxonomic proposals, based on morphology, for the South American subfamily Hyriinae, currently divided in three tribes: Hyriini, Castaliini and Rhipidodontini. Phylogenetic trees based on COI nucleotide sequences revealed at least four geographical groups of Castalia ambigua: northeast Amazon (Piriá, Tocantins and Caeté rivers), central Amazon, including C. quadrata (Amazon and Aripuanã rivers), north (Trombetas river), and C. ambigua from Peru. Genetic distances suggest that some specimens may be cryptic species. Among the Hyriini, a total evidence data set generated phylogenetic trees indicating that Paxyodon syrmatophorus and Prisodon obliquus are more closely related, followed by Triplodon corrugatus. The molecular clock, based on COI, agreed with the fossil record of Neotropical hyriids. The ancestor of both Australasian and Neotropical Hyriidae is estimated to have lived around 225million years ago.

  9. The complete maternally and paternally inherited mitochondrial genomes of the endangered freshwater mussel Solenaia carinatus (Bivalvia: Unionidae) and implications for Unionidae taxonomy.

    PubMed

    Huang, Xiao-Chen; Rong, Jun; Liu, Yong; Zhang, Ming-Hua; Wan, Yuan; Ouyang, Shan; Zhou, Chun-Hua; Wu, Xiao-Ping

    2013-01-01

    Doubly uniparental inheritance (DUI) is an exception to the typical maternal inheritance of mitochondrial (mt) DNA in Metazoa, and found only in some bivalves. In species with DUI, there are two highly divergent gender-associated mt genomes: maternal (F) and paternal (M), which transmit independently and show different tissue localization. Solenaia carinatus is an endangered freshwater mussel species exclusive to Poyang Lake basin, China. Anthropogenic events in the watershed greatly threaten the survival of this species. Nevertheless, the taxonomy of S. carinatus based on shell morphology is confusing, and the subfamilial placement of the genus Solenaia remains unclear. In order to clarify the taxonomic status and discuss the phylogenetic implications of family Unionidae, the entire F and M mt genomes of S. carinatus were sequenced and compared with the mt genomes of diverse freshwater mussel species. The complete F and M mt genomes of S. carinatus are 16716 bp and 17102 bp in size, respectively. The F and M mt genomes of S. carinatus diverge by about 40% in nucleotide sequence and 48% in amino acid sequence. Compared to F counterparts, the M genome shows a more compact structure. Different gene arrangements are found in these two gender-associated mt genomes. Among these, the F genome cox2-rrnS gene order is considered to be a genome-level synapomorphy for female lineage of the subfamily Gonideinae. From maternal and paternal mtDNA perspectives, the phylogenetic analyses of Unionoida indicate that S. carinatus belongs to Gonideinae. The F and M clades in freshwater mussels are reciprocal monophyly. The phylogenetic trees advocate the classification of sampled Unionidae species into four subfamilies: Gonideinae, Ambleminae, Anodontinae, and Unioninae, which is supported by the morphological characteristics of glochidia.

  10. Molecular resolution of the family Dreissenidae (Mollusca: Bivalvia) with emphasis on Ponto-Caspian species, including first report of Mytilopsis leucophaeata in the Black Sea basin.

    PubMed

    Therriault, Thomas W; Docker, Margaret F; Orlova, Marina I; Heath, Daniel D; MacIsaac, Hugh J

    2004-03-01

    Considerable uncertainty exists in determination of the phylogeny among extant members of the Dreissenidae, especially those inhabiting the Ponto-Caspian basin, as multiple systematic revisions based on morphological characteristics have failed to resolve relationships within this group of bivalves. In this study we use DNA sequence analyses of two mitochondrial gene fragments, 16S rRNA and cytochrome c oxidase subunit I (COI), to determine phylogenetic relationships among Dreissena rostriformis, D. bugensis, D. polymorpha, D. stankovici, Congeria kusceri, and Mytilopsis leucophaeata. Dreissena stankovici was determined to represent a sister taxa to D. polymorpha and both are more closely related to other extant Dreissena species than Congeria or Mytilopsis. Sequence divergence between D. rostriformis and D. bugensis was relatively low (0.3-0.4%), suggesting that these two taxa constitute a single species. However, environmental differences suggest two races of D. rostriformis, a brackish water race (rostriformis) and a freshwater race (bugensis). Spread of bugensis-type individuals into habitats in the Caspian Sea that are occupied by rostriformis-type individuals may create novel hybridization opportunities. Species-specific molecular markers also were developed in this study since significant intraspecific variation in morphological features complicates dreissenid identification. Using two gene fragments (nuclear 28S and 16S), we identified restriction fragment length polymorphisms (RFLPs) that distinguish among D. rostriformis/bugensis, D. polymorpha, and D. stankovici and revealed the presence of a cryptic invader to the Black Sea basin, Mytilopsis leucophaeata. This is the first report of this North American native in southern Europe.

  11. Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia.

    PubMed

    Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Wabnitz, Colette C C; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges

    2017-01-01

    Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems.

  12. Planktivory by alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) on microcrustacean zooplankton and dreissenid (Bivalvia: Dreissenidae) veligers in southern Lake Ontario

    USGS Publications Warehouse

    Mills, Edward L.; O'Gorman, Robert; Roseman, Edward F.; Adams, Connie; Owens, Randall W.

    1995-01-01

    The objective of this study was to describe the diet of young-of-the-year and adult alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in nearshore waters coincident with the colonization of Lake Ontario by Dreissena. Laboratory experiments and field observations indicated that alewife and rainbow smelt consumed dreissenid veligers and that the veligers remained intact and identifiable in the digestive tract for several hours. Dreissenid larvae were found in field-caught alewife and rainbow smelt in August 1992, even though veliger densities were low (<0.1/L). Zooplankton dominated the diet of all fish and veliger larvae were <0.1% of the biomass of prey eaten by these fish. Density of veligers and the distribution of settled dreissenids declined from west to east along the south shore of Lake Ontario. Based on veliger consumption rates we measured and the abundance of veligers and planktivores, we conclude that planktivory by alewife and smelt in the nearshore waters of Lake Ontario did not substantially reduce the number of veligers during 1991–1993. However, our results indicate that if the density of veligers in Lake Ontario decreases, and if planktivores remain abundant, planktivory on veliger populations could be significant.

  13. An attempt to extend the Habitat Harshness Hypothesis to tidal flats: A case study of Anomalocardia brasiliana (Bivalvia: Veneridae) reproductive biology

    NASA Astrophysics Data System (ADS)

    Corte, Guilherme Nascimento; Yokoyama, Leonardo Querobim; Amaral, A. Cecília Z.

    2014-10-01

    The Habitat Harshness Hypothesis (HHH) predicts that populations inhabiting the intertidal area of a dissipative beach should produce more gametes and have a longer reproductive cycle than those inhabiting an intermediate or reflective beach. This hypothesis was proposed for the exposed morphodynamic continuum between the reflective and dissipative states; however, no attempt has been made thus far to verify whether the HHH is valid for tidal flats. In this study, we analysed the reproductive cycle of Anomalocardia brasiliana in an intermediate beach and in a tidal flat and compared the results to determine whether the reproductive cycles of A. brasiliana were in agreement with the predictions of the HHH and to examine the possibility of extending this hypothesis to tidal flats. A continuous spawning season and synchrony between sexes were observed at both sites, although the reproductive effort was higher in the intermediate beach. The results of this first attempt did not support the extension of the HHH to tidal flats. It is possible that hypotheses that take into account only physical variables may not be the most adequate for describing environments with such a high species richness and high abundance as tidal flats. Nevertheless, other studies are necessary to confidently expand or refute the HHH with regard to tidal flats, and this topic should be considered as a priority in future investigations in sandy beach ecology.

  14. Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia

    PubMed Central

    Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Wabnitz, Colette C. C.; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges

    2017-01-01

    Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems. PMID:28118406

  15. Morphological and genetic variation in North Atlantic giant file clams, Acesta spp. (Bivalvia: Limidae), with description of a new cryptic species in the northwest Atlantic.

    PubMed

    Gagnon, Jean-Marc; Kenchington, Ellen; Port, Antony; Anstey, Lynne J; Murillo, Francisco Javier

    2015-08-27

    We analyze the morphological and genetic variability within and between seven species of Acesta and specimens recently collected in the northwest Atlantic using traditional morphological measurements, landmark-based geometric morphometrics, and the cytochrome oxidase subunit I (COI) gene sequences, with particular emphasis on North Atlantic species. Shell morphology and external shell appearance do not allow reliable distinction between the widely recognized northeastern Atlantic A. excavata and other northwest Atlantic species or populations of Acesta, with the exception of A. oophaga. Similarly, shape analysis reveals a wide variability within northeastern Atlantic A. excavata, and significant morphological overlap with A. bullisi from the Gulf of Mexico and A. rathbuni from the southwestern Pacific and South China Sea. Specimens from the northwestern and Mid-Atlantic display shell shapes marginally similar to that of A. excavata. These differences are at least partly related to anterior or posterior shifting of the shell body and to the opposite shifting of the hinge line/dorsal region and upper lunule. These morphological variations, along with the midline-width-ratio, explain much of the variability extracted by principal component analysis. Results from a mitochondrial DNA barcode approach (COI), however, suggest that the northwest Atlantic specimens belong to a new species for which we propose the name Acesta cryptadelphe sp. nov. Differences in larval shell sizes between northeastern and northwestern Atlantic specimens are consistent with this result.

  16. An annually-resolved palaeoenvironmental archive for the Eastern Boundary North Atlantic upwelling system: Sclerochronology of Glycymeris glycymeris (Bivalvia) shells from the Iberian shelf

    NASA Astrophysics Data System (ADS)

    Freitas, Pedro; Monteiro, Carlos; Butler, Paul; Reynolds, David; Richardson, Christopher; Gaspar, Miguel; Scourse, James

    2015-04-01

    The seasonally variable western Iberia upwelling system, albeit placed at a crucial climatic boundary position to record high frequency climate events, lacks well-dated high-resolution records of environmental variability. Bivalve shells provide robust high-resolution archives of oceanographic and climatic variability on timescales of decades to millennia. In particular, the North Atlantic Ocean region has recently seen several noteworthy sclerochronological and geochemical reconstructions based on bivalve shells (mainly Arctica islandica) of high frequency oceanographic and climatic conditions during the last millennium. However, due to the absence of Arctica islandica and similarly long-lived bivalves, sclerochronological palaeoenvironmental studies of southern European coastal shelf seas are scarce. In particular, none of these studies focus on reconstructing the variability of an eastern boundary upwelling system. The relatively long-lived bivalve (>100 years) Glycymeris glycymeris occurs in European and North West African coastal shelf seas and provides a valid annually resolved archive of environmental conditions during growth. Annual growth increment width series from living G. glycymeris shells, collected in 2014 on the western Iberian continental shelf (ca. 35 m water depth), were used to construct a statistically robust, ca. 70-year long absolutely-dated chronology. Sub-annually resolved (11 to 22 samples per year) oxygen stable isotope (δ18Oshell) data covering three years of shell growth, together with the direct evaluation of the time of growth mark deposition in shells collected during the autumn and winter months, were used to constrain the season of growth and to evaluate the seasonal bias of the sea-surface temperature signal preserved in the δ18Oshelldata. The growth increment width and δ18Oshell series, once robustly calibrated against modelled and instrumental oceanographic and climatic series, potentially provide novel insights into the variability of the western Iberia upwelling system and the associated mechanisms. This study was financed and conducted in the frame of the Portuguese Fundação para a Ciência e Tecnologia (FCT) GLYCY Project (contract PTDC/AAC-CLI/118003/2010).

  17. Long-term evolution of 5S ribosomal DNA seems to be driven by birth-and-death processes and selection in Ensis razor shells (Mollusca: Bivalvia).

    PubMed

    Vierna, Joaquín; González-Tizón, Ana M; Martínez-Lage, Andrés

    2009-10-01

    A study of nucleotide sequence variation of 5S ribosomal DNA from six Ensis species revealed that several 5S ribosomal DNA variants, based on differences in their nontranscribed spacers (NTS), occur in Ensis genomes. The 5S rRNA gene was not very polymorphic, compared with the NTS region. The phylogenetic analyses performed showed a between-species clustering of 5S ribosomal DNA variants. Sequence divergence levels between variants were very large, revealing a lack of sequence homogenization. These results strongly suggest that the long-term evolution of Ensis 5S ribosomal DNA is driven by birth-and-death processes and selection.

  18. Genetic Population Structure of Macridiscus multifarius (Mollusca: Bivalvia) on the Basis of Mitochondrial Markers: Strong Population Structure in a Species with a Short Planktonic Larval Stage.

    PubMed

    Ye, Ying Ying; Wu, Chang Wen; Li, Ji Ji

    2015-01-01

    The clam Macridiscus multifarius with a planktonic larval stage of about 10 days is an ecologically and economically important species in the coastal regions of China. In this study, 3 mt-DNA markers (COI, 12S rRNA, and ND1) were used to investigate the population structure and demography of wild M. multifarius populations in 3 coastal localities of the East China Sea (ZS and ZP populations) and Beibu Gulf in the South China Sea (BH population). Sequences of 685 bp in COI, 350 bp in 12S rRNA, and 496 bp in ND1 were determined. High level and significant FST values were obtained among the different localities on the basis of either COI (FST = 0.100-0.444, p < 0.05) or 12S rRNA (FST = 0.199-0.742, p < 0.05) gene, indicating a high degree of genetic differentiation among the populations. FST values were significant but weak for the ND1 gene because it is highly conservative. The median-joining network suggested an obvious genetic differentiation between ZS and BH populations, and the finding is consistent with the results of our demographic analyses using the unweighted pair group method with arithmetic mean. Our study unraveled the extant population genetic structure of M. multifarius and explained the strong population structure of a species with a short planktonic larval stage species; this information could be useful for fishery management measures, including artificial breeding and conservation.

  19. Sediment analysis does not provide a good measure of heavy metal bioavailability to Cerastoderma glaucum (Mollusca: Bivalvia) in confined coastal ecosystems

    SciTech Connect

    Arjonilla, M.; Gomez-Parra, A. ); Forja, J.M. )

    1994-06-01

    Sediments are considered a sink for metals entering the marine environment, especially in coastal areas. Once in the sediment layer, metals are distributed amongst all different phases of the sediment, governed by physicochemical conditions. One fraction is immobilized due to its incorporation into weakly reactive phases of the sediment; Another fraction may remain weakly bound to organic or mineral phases as sorbed, precipitated, or coprecipitated and complexed forms and can be assimilated by detritivorous and suspension-feeding benthic organisms. Many selective procedures have been suggested for metal extraction from sediments in order to estimate concentrations of fractions which are directly or indirectly available to the biota. The absence of a chemical treatment adequate for accurate quantification of metal bioavailability is well-known. Nevertheless, a good correlation between metal content in some organisms and in the sediment after a specific extraction treatment has sometimes been found so sediments are frequently used as indicators in pollution studies. In this paper, concentrations of heavy metals (Fe, Mn, Cu, Ph and Cd) in the cockle Cerastoderma glaucum, and in sediments at the same sampling locations are compared. C. glaucum is a suspension and deposit feeder, inhabiting a wide range of salinities. The study sampled 8 saltponds in the south of Cadiz Bay, located along a gradient of contamination produced by urban and industrial sewage effluents. The study sought to identify areas with different relative risk from metal pollution, in terms of biological effects and effects on water quality due to natural resuspension of sediments or to human relocation of sediments. C. glaucum was selected because of its wide distribution in the Bay, and also because it has no commercial value. This second fact means that its distribution and growth is not directly affected by man. 19 refs., 4 figs., 1 tab.

  20. Mechanisms and functional morphology associated with metal transport in Mercenaria mercenaria (bivalvia: mollusca): Progress report No. 7 for the contract period 1 September 1985 to 31 December 1986

    SciTech Connect

    Robinson, W.E.; Morse, M.P.

    1987-02-04

    Studies on metal transport in the quahog, Mercenaria mercenaria, are reported. Podocytes, a specialized type of cell that functions in ultrafiltration, have been identified in the pericardial glands of the quahog using transmission and scanning electron microscopy raising the question of whether metals may reach the kidney via the primary urine, or whether most metals arrive in the kidney via the blood. The accumulation of /sup 109/Cd in quahog extracellular kidney granules suggests the involvement the kidney cell's lysosomal system in the overall process of metal sequestration. The different patterns of metal interactions observed in the quahog kidney, digestive gland and gill demonstrate that each of these three organs utilizes different mechanisms of metal detoxification and accumulation.

  1. Large Vesicomyidae (Mollusca: Bivalvia) from cold seeps in the Gulf of Guinea off the coasts of Gabon, Congo and northern Angola

    NASA Astrophysics Data System (ADS)

    von Cosel, Rudo; Olu, Karine

    2009-12-01

    Two new genera and three new species of large Vesicomyidae are described from cold-seep sites on pockmarks and other sulfide-rich environments in the Gulf of Guinea (tropical east Atlantic) off Gabon, Congo (Brazzaville) and northern Angola, from 500 to 4000 m depth: " Calyptogena" (s.l.) regab n. sp., Wareniconcha (n.g.) guineensis (Thiele and Jaeckel 1931), Elenaconcha guiness n.g. n. sp., and Isorropodon atalantae n. sp. For two other species already taken by the R/V Valdivia in 1898, Calyptogena valdiviae (Thiele and Jaeckel 1931) and Isorropodon striatum (Thiele and Jaeckel 1931) new localities were discovered, and the species are rediscussed. E. guiness n.g. n.sp. is also recorded from off Banc d'Arguin, Mauritania, collected by commercial fishing vessels. The vesicomyid species here treated were encountered in different depth ranges along the Gabon-Congo-Angola margin, between 500 and 4000 m depth, and it was found that, in comparison with the dredge samples taken by the Valdivia expedition off southern Cameroon and off Rio de Oro (both at 2500 m), the same species occur in other depth ranges, in some cases with a vertical difference of more than 1000 m. .That means that the species are not confined to a given depth thought being typical for them and that the characteristics of the biotope are likely to play a major role in the distribution of the vesicomyids associated to cold seeps or other reduced environments along the West African margin.

  2. Occurrence of the cis-4,7,10, trans-13-22:4 fatty acid in the family Pectinidae (Mollusca: Bivalvia).

    PubMed

    Kraffe, Edouard; Grall, Jacques; Palacios, Elena; Guerra, Citlali; Soudant, Philippe; Marty, Yanic

    2010-05-01

    The present study aimed to elucidate the effective phylogenetic specificity of distribution of a cis-4,7,10, trans-13-22:4 (22:4(n-9)Delta13trans) among pectinids. For this purpose, we extended the analysis of membrane glycerophospholipids FA composition to 13 species of scallops, covering 11 genera and 7 tribes representatives of the three subfamilies Chlamydinae, Palliolinae and Pectininae and the subgroup Aequipecten. In species belonging to the subfamily Pectininae and the Aequipecten subgroup, 22:4(n-9)Delta13trans was found in substantial amounts, but it was absent in other species belonging to the subfamilies Chlamydinae and Palliolinae. Homologous non-methylene-interrupted (NMI) FA, also hypothesized to differ along phylogenetic lines in bivalves, were totally absent or present only in trace amounts in representatives of the Aequipecten subgroup but ranged from 0.3 to 4.5% of the total FA in Pectinidae, Chlamydinae, and Palliolinae subfamilies. The species-specific occurrence of NMI and 22:4(n-9)Delta13trans FA in membrane lipids of pectinids agrees with the most recent phylogenies based on shell morphology and molecular characteristics. We examined the potential timing of the appearance of 22:4(n-9)Delta13trans in pectinids on a geologic time scale.

  3. Characterisation of 12 microsatellite loci in the Vietnamese commercial clam Lutraria rhynchaena Jonas 1844 (Heterodonta: Bivalvia: Mactridae) through next-generation sequencing.

    PubMed

    Thai, Binh Thanh; Tan, Mun Hua; Lee, Yin Peng; Gan, Han Ming; Tran, Trang Thi; Austin, Christopher M

    2016-05-01

    The marine clam Lutraria rhynchaena is gaining popularity as an aquaculture species in Asia. Lutraria populations are present in the wild throughout Vietnam and several stocks have been established and translocated for breeding and aquaculture grow-out purposes. In this study, we demonstrate the feasibility of utilising Illumina next-generation sequencing technology to streamline the identification and genotyping of microsatellite loci from this clam species. Based on an initial partial genome scan, 48 microsatellite markers with similar melting temperatures were identified and characterised. The 12 most suitable polymorphic loci were then genotyped using 51 individuals from a population in Quang Ninh Province, North Vietnam. Genetic variation was low (mean number of alleles per locus = 2.6; mean expected heterozygosity = 0.41). Two loci showed significant deviation from Hardy-Weinberg equilibrium (HWE) and the presence of null alleles, but there was no evidence of linkage disequilibrium among loci. Three additional populations were screened (n = 7-36) to test the geographic utility of the 12 loci, which revealed 100 % successful genotyping in two populations from central Vietnam (Nha Trang). However, a second population from north Vietnam (Co To) could not be successfully genotyped and morphological evidence and mitochondrial variation suggests that this population represents a cryptic species of Lutraria. Comparisons of the Qang Ninh and Nha Trang populations, excluding the 2 loci out of HWE, revealed statistically significant allelic variation at 4 loci. We reported the first microsatellite loci set for the marine clam Lutraria rhynchaena and demonstrated its potential in differentiating clam populations. Additionally, a cryptic species population of Lutraria rhynchaena was identified during initial loci development, underscoring the overlooked diversity of marine clam species in Vietnam and the need to genetically characterise population representatives prior to microsatellite development. The rapid identification and validation of microsatellite loci using next-generation sequencing technology warrant its integration into future microsatellite loci development for key aquaculture species in Vietnam and more generally, aquaculture countries in the South East Asia region.

  4. Temporal variation in life-history traits of the clam Tivela mactroides (Bivalvia: Veneridae): Density-dependent processes in sandy beaches

    NASA Astrophysics Data System (ADS)

    Turra, Alexander; Petracco, Marcelo; Amaral, A. Cecilia Z.; Denadai, Márcia R.

    2014-10-01

    Temporal variation in the structure and dynamics of a population of Tivela mactroides was examined over two periods (2003-2004 and 2007-2008) in the southern part of Caraguatatuba Bay, southeastern Brazil. During the first period from January 2003 to October 2004, sampling was conducted monthly. Sampling in the second period was performed in the summer (January and February 2007 and 2008) and winter (July and August 2007 and 2008). The von Bertalanffy growth function was applied to estimate growth parameters for both periods from length-frequency distributions. Production was determined using the mass-specific growth rate method. Results indicated that the mean abundance (±SE) of T. mactroides varied sharply between the two periods, with an increase of almost 150 times from 2003 to 2004 (8.67·102 ± 0.83·102 ind m-1) to 2007-2008 (1.25·105 ± 3.33·104 ind m-1). The higher abundance in the second period was related to successful recruitment events. While the mean biomass and the production were higher in the second (5.43 ± 0.87 kg AFDM m-1 and 7.89 kg AFDM m-1 yr-1) than in the first period (0.18 ± 0.02 kg AFDM m-1 and 0.18 kg AFDM m-1 yr-1), lower values of shell length, curvature parameter, asymptotic length of the VBGF, and the growth index phi-prime in 2007-2008 (17.57 ± 1.35 mm; K = 0.40 yr-1; L∞ = 38.60 mm, ϕ‧ = 2.78) than in 2003-2004 (26.21 ± 1.21 mm; K = 1.00 yr-1; L∞ = 40.75 mm, ϕ‧ = 3.22) were related to a strongly density-dependent growth process in the second period. The oscillation in growth observed in the second, but not in the first period also indicates a process of density-dependent growth. These sharp temporal variations in population parameters of T. mactroides suggest the occurrence of density-dependent processes, and reinforce the importance of these processes in structuring sandy-beach populations.

  5. Filter-feeding, food utilization, and nutrient remineralization by Corbicula fluminea (bivalvia) and its contribution to nutrient cycling in a North Carolina River

    SciTech Connect

    Lauritsen, D.D.

    1985-01-01

    The introduced Asiatic clam Corbicula fluminea is quite prolific, and since it is a filter-feeder, it can be expected to influence the cycling of nutrients within its habitat as a result of its feeding and excretory activities. Factors affecting filtration rates, food utilization, and excretion of metabolic wastes (ammonia and phosphate) were determined by laboratory experiments, and these physiological processes were then extrapolated to field estimates of Corbicula found in the upper Chowan River, N.C., to obtain an estimate of the potential impact the clams can have on nutrient cycling in the river. Clam filtration rates of four different /sup 14/C-labeled algae species (two greens, a blue-green, and a diatom) were similar, although partitioning of the ingested isotope showed significant differences between the algal foods. The diatom species was the most efficiently utilized by the clams, with more than 80% of the isotope ingested recovered in clam tissues. Corbicula freshly collected from the Chowan River excreted substantially more ammonia than phosphate, and rates of excretion of both nutrients were highest in summer. Clam excretion rates were much higher than sediment fluxes, and as a source of recycled nutrients, these clams could provide about one third of the nitrogen and phosphate requirements of the phytoplankton in the upper Chowan.

  6. Genomic in situ hybridization identifies parental chromosomes in hybrid scallop (Bivalvia, Pectinoida, Pectinidae) between female Chlamys farreri and male Argopecten irradians irradians

    PubMed Central

    Huang, Xiaoting; Bi, Ke; Lu, Wei; Wang, Shi; Zhang, Lingling; Bao, Zhenmin

    2015-01-01

    Abstract Interspecific crossing was artificially carried out between Chlamys farreri (Jones & Preston, 1904) ♀ and Argopecten irradians irradians (Lamarck, 1819) ♂, two of the dominant cultivated scallop species in China. Genomic in situ hybridization (GISH) was used to examine the chromosome constitution and variation in hybrids at early embryonic stage. The number of chromosomes in 66.38% of the metaphases was 2n = 35 and the karyotype was 2n = 3 m + 5 sm + 16 st + 11 t. After GISH, two parental genomes were clearly distinguished in hybrids, most of which comprised 19 chromosomes derived from their female parent (Chlamys farreri) and 16 chromosomes from their male parent (Argopecten irradians irradians). Some chromosome elimination and fragmentation was also observed in the hybrids. PMID:26140161

  7. First record and description of metacercariae of Curtuteria arguinae n. sp. (Digenea: Echinostomatidae), parasite of cockles Cerastoderma edule (Mollusca: Bivalvia) in Arcachon Bay, France.

    PubMed

    Desclaux, Céline; Russell-Pinto, Fernanda; de Montaudouin, Xavier; Bachelet, Guy

    2006-06-01

    A new Himasthlinae species, Curtuteria arguinae, is described as metacercariae from the cockle Cerastoderma edule (L.), collected at Banc d'Arguin (southwestern France). These metacercariae encysted preferentially in the mantle and also in the foot of cockles. Encysted and chemically excysted metacercariae were studied by light microscopy and scanning electron microscopy, respectively. Excysted metacercariae were elongated and curved ventrally. They bore a 33-spine circumoral collar. Sensory papillae were arranged around the oral sucker and also symmetrically along the ventral surface body, from the collar to the acetabulum. The dorsal and ventral tegument surfaces were densely packed with similar pointed spines. The posterior end of the body was without any spines. Among the Curtuteria species described previously, only Curtuteria haematopodis Smogorjewskaja and Iskova, 1966 had the same number of circumoral collar spines. A 6-yr field survey showed that the cockle population at Banc d'Arguin was subjected to a summer infection of C. arguinae. Curtuteria arguinae phenology of infection is characterized by interannual variability and seasonality (beginning in July-August and maximum in autumn). The first intermediate and final hosts remain unknown.

  8. Bucardium grateloupianum n. sp. from the Lower Miocene of Aquitaine with    taxonomic comments on some fossil species from Europe (Bivalvia, Cardiidae).

    PubMed

    Perna, Rafael La

    2016-10-26

    The genus Bucardium J. E. Gray, 1853 has been widely used in the past literature, either for living and fossil cardiids, but only a single species was known, its type species B. ringens (Bruguière, 1789), living in the tropical waters of West Africa. Another species, from the Lower Miocene of the Aquitaine Basin, turned out to be undescribed, though known since the 19th century. It is herein described as Bucardium grateloupianum n. sp. The genus seems to have always had a low diversity and a tropical distribution. Its disappearance in Europe coincides with the general cooling trend recorded after the Middle Miocene. Several poorly known cardiids from the Lower-Middle Miocene of France and Austria and from the Upper Oligocene of Hungary show closer morphological affinities with the living Cardium indicum Lamarck, 1819, rather than with the genus Bucardium or with Cardium costatum Linnaeus, 1758, the type species of Cardium Linnaeus, 1758. These affinities suggest the need of a systematic reappraisal of the living and fossil species currently assigned to Cardium.

  9. Combined Use of Morphological and Molecular Tools to Resolve Species Mis-Identifications in the Bivalvia The Case of Glycymeris glycymeris and G. pilosa

    PubMed Central

    Holmes, Anna; Bušelić, Ivana; Thébault, Julien; Featherstone, Amy

    2016-01-01

    Morphological and molecular tools were combined to resolve the misidentification between Glycymeris glycymeris and Glycymeris pilosa from Atlantic and Mediterranean populations. The ambiguous literature on the taxonomic status of these species requires this confirmation as a baseline to studies on their ecology and sclerochronology. We used classical and landmark-based morphometric approaches and performed bivariate and multivariate analyses to test for shell character interactions at the individual and population level. Both approaches generated complementary information. The former showed the shell width to length ratio and the valve asymmetry to be the main discriminant characters between Atlantic and Mediterranean populations. Additionally, the external microsculpture of additional and finer secondary ribs in G. glycymeris discriminates it from G. pilosa. Likewise, landmark-based geometric morphometrics revealed a stronger opisthogyrate beak and prosodetic ligament in G. pilosa than G. glycymeris. Our Bayesian and maximum likelihood phylogenetic analyses based on COI and ITS2 genes identified that G. glycymeris and G. pilosa form two separate monophyletic clades with mean interspecific divergence of 11% and 0.9% for COI and ITS2, respectively. The congruent patterns of morphometric analysis together with mitochondrial and nuclear phylogenetic reconstructions indicated the separation of the two coexisting species. The intraspecific divergence occurred during the Eocene and accelerated during the late Pliocene and Pleistocene. Glycymeris pilosa showed a high level of genetic diversity, appearing as a more robust species whose tolerance of environmental conditions allowed its expansion throughout the Mediterranean. PMID:27669452

  10. Megafauna recovered from a cold hydrocarbon seep in the deep Alaskan Beaufort Sea, including a new species of Axinus (Thracidae: Bivalvia: Mollusca)

    NASA Astrophysics Data System (ADS)

    Powell, C. L.; Valentich-Scott, P.; Lorenson, T. D.; Edwards, B. D.

    2011-12-01

    Several specimens of a new species of Axinus and a single well-worn gastropod columella provisionally assigned to the genus Neptunea (Buccinidae: Gastropoda: Mollusca) were recently recovered from at least two cores, the longest of which is 5.72 m long, from a large seafloor mound, informally named the Canning Seafloor Mound (CSM). The CSM is located at 2,530 m water depth on the Alaskan Beaufort Sea slope north of Camden Bay and is a fluid explosion feature containing methane hydrate and methane-saturated sediments overlying a folded and faulted deep basin. Only two modern species of Axinus are currently known. Axinus grandis (Verrill & Smith, 1885) is a northern Atlantic species and the recently described species, A. cascadiensis Oliver and Holmes (2007), is only known from Baby Bare Seamount, Cascadia Basin, northeastern Pacific Ocean. Common fragments, single valves, and a single articulated specimen represent this new Axinus species. These shells were distributed over nearly the entire length of the primary core. All specimens show wear and (or) dissolution. The age of these specimens is unknown and no living representatives were encountered. The genus Axinus has a fossil record back to the early Eocene in England and the Paleocene and Eocene in Egypt. Biogeographically the genus appears to have originated in the Tethys Sea and became established in the Atlantic Ocean during the Eocene, spreading across the Arctic Ocean in the late Tertiary. With the opening of the Bering Strait in the latest Miocene or early Pliocene the genus Axinus migrated southwest into the northeast Pacific. Interestingly, hydrocarbon seep deposits are also present on the adjacent North Slope of Alaska in the Marsh Anticline at Carter Creek, Camden Bay. These rocks, the Nuwok beds, contain abundant Thracidae bivalve of the genus Thracia, but not Axinus, however the rocks also represent cold seep deposits. These rocks have been variously dated from Oligocene to Pliocene and the exact age remains uncertain. Neptunea are a predatory snails well represented in the earliest Miocene to Holocene of the northern Pacific Ocean and in the late Pliocene to Holocene of the northern Atlantic. The presence of Neptunea at CSM, if identified properly, gives a maximum age for these deposits of latest Miocene or early Pliocene, after the opening of the Bering Strait, although they could be as young as Holocene.

  11. Reproductive traits of the symbiotic pea crab Austinotheres angelicus (Crustacea, Pinnotheridae) living in Saccostrea palmula (Bivalvia, Ostreidae), Pacific coast of Costa Rica

    PubMed Central

    Salas-Moya, Carolina; Mena, Sebastián; Wehrtmann, Ingo S.

    2014-01-01

    Abstract Pea crabs of the family Pinnotheridae exhibit a symbiotic life style and live associated with a variety of different marine organisms, especially bivalves. Despite the fact that pea crabs can cause serious problems in bivalve aquaculture, the available information about the ecology of these crabs from Central America is extremely limited. Therefore, the present study aimed to describe different reproductive features of the pinnotherid crab Austinotheres angelicus associated with the oyster Saccostrea palmula in the Golfo de Nicoya, Pacific coast of Costa Rica. Monthly sampling was conducted from April to December 2012. Average carapace width (CW) of the 47 analyzed ovigerous females was 7.62 mm. The species produced on average 2677 ± 1754 recently -extruded embryos with an average volume of 0.020 ± 0.003 mm3; embryo volume increased during embryogenesis by 21%, but did not vary significantly between developmental stages. Brood mass volume varied greatly (between 11.7 and 236.7 mm3), and increased significantly with female CW. Females invested on average 76.7% (minimum: 21.7%; maximum: 162.8%) of their body weight in brood production, which confirms a substantially higher energy allocation for embryo production in pinnotherid crabs compared to free-living decapods. PMID:25561840

  12. Long-term feeding with Euglena gracilis cells modulates immune responses, oxidative balance and metabolic condition in Diplodon chilensis (Mollusca, Bivalvia, Hyriidae) exposed to living Escherichia coli.

    PubMed

    Bianchi, Virginia A; Castro, Juan M; Rocchetta, Iara; Nahabedian, Daniel E; Conforti, Visitación; Luquet, Carlos M

    2015-02-01

    We evaluated the modulating effect of long-term feeding with lyophilized Euglena gracilis cells on immune response, oxidative balance and metabolic condition of the freshwater mussel Diplodon chilensis. Mussels, previously fed with Scenedesmus vacuolatus (SV) or E. gracilis (EG) for 90 days, were challenged with an environmentally relevant concentration of Escherichia coli in water for 5 days, under feeding or starvation conditions. EG diet increased overall phagocytic activity and tissue hemocyte accumulation (gill and mantle), and favored hemocyte viability upon E. coli challenge. Tissular hemocyte accumulation, and humoral bacteriolytic activity and protein content were similarly stimulated by EG and E. coli, with no further effect when both stimuli were combined. Both, E. coli challenge and EG diet reduced gill bacteriolytic activity with respect to nonchallenged SV mussels, while no effect was observed in challenged EG mussels. Gill and digestive gland protein contents, along with digestive gland bacteriolytic activity were higher in EG than in SV mussels. Both SV and EG mussels showed increased gill mass upon E. coli challenge, while digestive gland mass was increased by bacterial challenge only in SV mussels. Bacterial challenge produced no effect on humoral reactive oxygen species levels of both groups. Total oxyradical scavenging capacity levels was reduced in challenged SV mussels but remained unaffected in EG ones. In general, EG diet decreased glutathione S-transferase and catalase activities in gill and digestive gland, compared with SV diet; but increased enzyme activity was evident in challenged mussels of both groups. Gill and digestive gland lipid peroxidation levels were higher in EG than in SV mussels but E. coli challenge had stronger effect on SV mussels. Adductor muscle RNA:DNA ratio was higher in EG mussels than in SV ones, and increased upon E. coli challenge in mussels of both groups. E. gracilis can be suggested as a nutritional and protective diet complement suitable for filtering bivalves. However, our results obtained from starved mussels show that starvation periods after supplying this diet should be avoided, since these could revert part of the acquired benefits and/or exacerbate detrimental effects.

  13. Where’s Waldo? A new commensal species, Waldo arthuri (Mollusca, Bivalvia, Galeommatidae), from the Northeastern Pacific Ocean

    PubMed Central

    Valentich-Scott, Paul; Ó Foighil, Diarmaid; Li, Jingchun

    2013-01-01

    Abstract A galeommatid bivalve mollusk, representing a new species, is described from off the coasts of California and Vancouver Island, British Columbia. The new bivalve has a commensal relationship with the heart urchin, Brisaster latifrons. It has been observed crawling between the oral spines of this urchin, frequently near the peristome. The bivalve has been recorded from 80 (Vancouver Island) to 444 (southern California) meters depth, in muddy sediments. In common with other galeommatoideans, the new species broods its young; however it differs from the large majority of commensal members in lacking planktotrophic larval development. Waldo arthuri, new species, has multiple morphological, ecological and developmental similarities to other members of the genus Waldo Nicol, 1966, from the southern Atlantic and Antarctic Oceans. This is most pronounced for the Argentine species, Waldo paucitentaculatus Zelaya & Ituarte, 2013, Waldo arthuri’s sister speciesin nuclear and mitochondrial gene trees. Despite this close relationship, Waldo arthuri is phylogentically distinct and possesses several hinge, shell sculpture, foot, and mantle tentacle characteristics that merit its description as new. PMID:23878515

  14. Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae)

    PubMed Central

    Glover, Emily A.; Taylor, John D.

    2016-01-01

    Abstract A new shallow water species of the lucinid bivalve Pleurolucina is described from Curaçao in the southern Caribbean Sea and compared with known species of the genus from the western Atlantic and eastern Pacific Oceans. Although confused with the Floridian species Pleurolucina leucocyma, it is most similar to the eastern Pacific Pleurolucina undata. As in all studied lucinids, the new species possesses symbiotic bacteria housed in the ctenidia. The shell microstructure is unusual with repeated and intercalated conchiolin layers that have sublayers of ‘tulip-shaped’ calcareous spherules. Predatory drillings by naticid gastropods frequently terminate at the conchiolin layers. PMID:27853404

  15. In vivo effects of brown tide on the feeding function of the gill of the northern quahog Mercenaria mercenaria (Bivalvia: Veneridae).

    PubMed

    Robbins, Heather M; Bricelj, V Monica; Ward, J Evan

    2010-08-01

    The in vivo response of adult northern quahogs, Mercenaria mercenaria, to Aureococcus anophagefferens (brown tide) at the level of the gill was determined using video-endoscopy. Feeding activity, particle-approach velocities, and ventral-groove-transport velocities were documented after the quahogs were exposed to Isochryis galbana (baseline observations) supplemented with either toxic or nontoxic A. anophagefferens at two bloom concentrations (8 x 10(5) or 2 x 10(6) cells ml(-1)). Externally, there was no evidence of adverse effects of brown tide on feeding, as siphons remained extended and dilated. Toxic brown tide at both concentrations elicited gill muscular contractions, intermittent cessation of water flow, and decreased particle loading within the pallial cavity. The 8 x 10(5) cell ml(-1) toxic treatment had no significant effect on approach velocities or ventral-groove-transport velocities after 2 h, although time-averaging showed significant reduction of the latter during the last 30 min of exposure. The higher concentration of toxic brown tide caused a significant decrease in these velocities after only 1 h. Nontoxic brown tide produced none of these effects. Thus, A. anophagefferens compromised quahog feeding by stimulating contractions of the branchial musculature and interfering with lateral and ventral groove ciliary beating. These effects were both time- and concentration-dependent and could be caused by either a dopaminergic or a serotonergic toxic factor.

  16. New threats of an old enemy: the distribution of the shipworm Teredo navalis L. (Bivalvia: Teredinidae) related to climate change in the Port of Rotterdam area, the Netherlands.

    PubMed

    Paalvast, Peter; van der Velde, Gerard

    2011-08-01

    The effects of four climate change scenarios for the Netherlands on the distribution of the shipworm upstream of the Rhine-Meuse estuary are described. Global warming will cause dry and warmer summers and decreased river discharges. This will extend the salinity gradient upstream in summer and fall and may lead to attacks on wooden structures by the shipworm. Scenarios including one or two degree temperature increases by 2050 compared to 1990 with a weak change in the air circulation over Europe will lead to an increased chance of shipworm damage upstream from once in 36 years to once in 27 or 22 years, respectively; however, under a strong change in air circulation, the chance of shipworm damage increases to once in 6 or 3 years, respectively. The upstream expansion of the distribution of the shipworm will also be manifested in other northwest European estuaries and will be even stronger in southern Europe.

  17. [Lipid and fatty acid profile of Perna viridis, green mussel (Mollusca: Bivalvia) in different areas of the Eastern Venezuela and the West Coast of Trinidad].

    PubMed

    Koftayan, Tamar; Milano, Jahiro; D'Armas, Haydelba; Salazar, Gabriel

    2011-03-01

    The species Perna viridis is a highly consumed species, which fast growth makes it an interesting aquaculture alternative for Venezuelan and Trinidad coasts. With the aim to contribute with its nutritional value information, this study analyzed lipid and fatty acid contents from samples taken in five locations from Eastern Venezuela and three from Trinidad West Coast. Total lipids were extracted and quantified, from a pooled sample of 100 organisms per location, by standard gravimetric methods, and their identification and quantification was done by TLC/FID (Iatroscan system). Furthermore, the esterified fatty acids of total lipid, phospholipids and triacylglycerols were identified and quantified by gas chromatography. Eastern Venezuela samples from Los Cedros, La Brea and Chaguaramas showed the highest total lipid values of 7.92, 7.74 and 7.53, respectively, and the minimum values were obtained for La Restinga (6.08%). Among lipid composition, Chacopata samples showed the lowest phospholipid concentration (48.86%) and the maximum values for cholesterol (38.87%) and triacylglycerols (12.26%); besides, La Esmeralda and Rio Caribe samples exhibited maximum phospholipids (88.71 and 84.93 respectively) and minimum cholesterol (6.50 and 4.42%) concentrations. Saturated fatty acids represented between 15.04% and 65.55% within total lipid extracts, with maximum and minimum values for La Esmeralda and Chacopata, respectively. Polyunsaturated results resulted between 7.80 and 37.18%, with higher values in La Brea and lower values in La Esmeralda. For phospholipids, saturated fatty acids concentrations varied between 38.81 and 48.68% for Chaguaramas and Chacopata samples, respectively. In the case of polyunsaturated fatty acids, these varied between non detected and 34.51%, with high concentrations in Los Cedros (27.97%) and Chaguaramas (34.51%) samples. For the triacylglycerols, the saturated fatty acids composition oscillated between 14.27 and 53.80% with low concentrations for Chacopata and high concentration for La Restinga; the polyunsaturated fatty acids were between 4.66 and 35.55% with lower values for Chacopata and higher values for Chaguaramas samples. P. viridis is recommended for human being consumption, according to the high content of unsaturated fatty acids found for this species.

  18. Surface morphology of Diplodon expansus (Küster, 1856; Mollusca, Bivalvia, Hyriidae) gill filaments after exposure to environmentally relevant concentrations of atrazine herbicide.

    PubMed

    Nogarol, Larissa Rosa; Brossi-Garcia, Ana Luiza; Fontanetti, Carmem Silvia

    2012-06-01

    Brazilian endemic species Diplodon expansus (Küster, 1856) is found in freshwater bodies in the country's southeast, in large anthropogenic influence regions especially with an extensive agriculture emphasis. One of the main pesticides used in the species occurrence region is the atrazine herbicide, which has a great contamination potential in the aquatic environment. Therefore, several studies into its toxicity in aquatic systems have been developed. However, the tested concentrations are usually very high and rarely found in the environment and the short-term exposure responses in other aquatic organisms such as native bivalves are still scarce. Thus, this study sought to consider the potential effects of environmentally realistic concentrations of atrazine herbicide on the surface morphology of gill filaments of the bivalve D. expansus under laboratory-controlled conditions after short-term exposure. None of the animals died before the end of the experiment. The main alterations were observed on the frontal surface of filaments, which include mucus accumulation, cilia loss, and disruption. Mucus increased secretion and accumulation in the frontal filaments region preceded as a protective mechanism. Cilia loss and disruption on the frontal surface of the gill filament indicated that ciliated frontal cells were more sensitive to atrazine exposure and these alterations may cause gills functional damages, compromising the uptake of food particles and respiration. Therefore, higher sublethal concentrations of atrazine may compromise the survival and consequently the population of D. expansus in agriculture areas after a longer period of continuous exposure.

  19. Large-scale mitochondrial COI gene sequence variability reflects the complex colonization history of the invasive soft-shell clam, Mya arenaria (L.) (Bivalvia)

    NASA Astrophysics Data System (ADS)

    Lasota, Rafal; Pierscieniak, Karolina; Garcia, Pascale; Simon-Bouhet, Benoit; Wolowicz, Maciej

    2016-11-01

    The aim of the study was to determine genetic diversity in the soft-shell clam Mya arenaria on a wide geographical scale using mtDNA COI gene sequences. Low levels of genetic diversity was found, which can most likely be explained by a bottleneck effect during Pleistocene glaciations and/or selection. The geographical genetic structuring of the studied populations was also very low. The star-like phylogeny of the haplotypes indicates a relatively recent, rapid population expansion following the glaciation period and repeated expansion following the founder effect(s) after the initial introduction of the soft-shell clam to Europe. North American populations are characterized by the largest number of haplotypes, including rare ones, as expected for native populations. Because of the founder effect connected with initial and repeated expansion events, European populations have significantly lower numbers of haplotypes in comparison with those of North America. We also observed subtle differentiations among populations from the North and Baltic seas. The recently founded soft-shell clam population in the Black Sea exhibited the highest genetic similarity to Baltic populations, which confirmed the hypothesis that M. arenaria was introduced to the Gulf of Odessa from the Baltic Sea. The most enigmatic results were obtained for populations from the White Sea, which were characterized by high genetic affinity with American populations.

  20. Morphological and genetic diversity of the wood-boring Xylophaga (Mollusca, Bivalvia): new species and records from deep-sea Iberian canyons.

    PubMed

    Romano, Chiara; Voight, Janet Ruth; Pérez-Portela, Rocío; Martin, Daniel

    2014-01-01

    Deep-sea bivalves of the Xylophagaidae, a poorly known group, are obligate wood-borers. Deployment of wood in three submarine canyons off the Iberian coast, the Blanes and La Fonera Canyons (Mediterranean Sea) and the Avilés Canyon (Cantabric Sea, Bay of Biscay), lead to the discovery of four xylophagaid species in our samples. Xylophaga dorsalis (the dominant species), X. atlantica, X. cf. anselli and the new species X. brava, were identified on the basis of morphological data, and supported by a phylogenetic reconstruction based on the nuclear genes 18S rDNA and 28S rDNA and including several genus of Xylophagaidae. Genetic divergence between species of Xylophaga varied between genes, ranging from 0.5 to 4.0% for the 18SrDNA and from 4.1 to 16.6% for the 28SrDNA. Xylophaga brava sp. nov. appeared to be restricted to the Mediterranean and morphologically resembled the closely related X. cf. anselli from the Cantabrian Sea. However, they clearly diverged in two well-supported clades. Low levels of intraspecific variability and higher interspecific divergence between species also supported the existence of these two different species. Morphologically they differ in the number of cirri at the siphon openings, in the shape of the posterior shell and in the size of prodissoconch II. The new species is characterized by having weak, poorly mineralized mesoplax and siphons united throughout, covered by a periostracal, non-calcified tube; distinct proximal and distal siphons, the former translucent and soft, the latter muscular, with concentric rings. Xylophaga atlantica, previously known only from the western Atlantic, is reported for the first time in the Mediterranean Sea. Whether its presence in the Mediterranean indicates its natural distribution or reflects its recent introduction is unknown. Although xylophagaids have been previously reported to recruit heavily to wood deposited on the seabed, these four species colonized wood suspended 30 m above the seafloor.

  1. Cementing mussels to oysters in the pteriomorphian tree: a phylogenomic approach

    PubMed Central

    González, Vanessa L.; Bieler, Rüdiger; Giribet, Gonzalo

    2016-01-01

    Mussels (Mytilida) are a group of bivalves with ancient origins and some of the most important commercial shellfish worldwide. Mytilida consists of approximately 400 species found in various littoral and deep-sea environments, and are part of the higher clade Pteriomorphia, but their exact position within the group has been unstable. The multiple adaptive radiations that occurred within Pteriomorphia have rendered phylogenetic classifications difficult and uncertainty remains regarding the relationships among most families. To address this phylogenetic uncertainty, novel transcriptomic data were generated to include all five orders of Pteriomorphia. Our results, derived from complex analyses of large datasets from 41 transcriptomes and evaluating possible pitfalls affecting phylogenetic reconstruction (matrix occupancy, heterogeneity, evolutionary rates, evolutionary models), consistently recover a well-supported phylogeny of Pteriomorphia, with the only exception of the most complete but smallest data matrix (Matrix 3: 51 genes, 90% gene occupancy). Maximum-likelihood and Bayesian mixture model analyses retrieve strong support for: (i) the monophyly of Pteriomorphia, (ii) Mytilida as a sister group to Ostreida, and (iii) Arcida as sister group to all other pteriomorphians. The basal position of Arcida is congruent with its shell microstructure (solely composed of aragonitic crystals), whereas Mytilida and Ostreida display a combination of a calcitic outer layer with an aragonitic inner layer composed of nacre tablets, the latter being secondarily lost in Ostreoidea. PMID:27358369

  2. THREE YEAR VARIATION IN SHELL GROWTH OF THEMUSSEL, ELLIPTIO WACCAMAWENSIS (LEA), IN LAKEWACCAMAW, A BAY LAKE IN NORTH CAROLINA

    EPA Science Inventory

    Freshwater mussels (Bivalvia: Unionidae) are one of the most endangered animal taxa in North America, and continued research on unionids will improve management decisions regarding their conservation. One unexplored aspect of unionid ecology is the magnitude of interannual variat...

  3. Effects of Surface Texture of Articulated Concrete Mattress Blocks on Their Habitat Value. Lower Mississippi River Environmental Program Report 19

    DTIC Science & Technology

    1992-09-01

    of trichoptera, chironomidae, ephemeroptera, odonata , collembola, amphipoda, isopoda, hydracarinia, gas- tropoda, bivalvia, naididae, hydrozoa...Ephemeroptera Baetis sp. CaenIs sp. Heptagenia sp. Isonychia sp. Stenocron sp. Odonata Neurocordulia moles ta (Continued) 21 Table 1 (Concluded) .Taxonomic

  4. EXPERIMENTAL STUDIES OF INTERACTIONS BETWEEN TWO UNIONIDS, ELLIPTIO WACCAMAWENSIS AND LEPTODEA OCHRACEA: VARIATION IN NEGATIVE AND POSITIVE EFFECTS

    EPA Science Inventory

    Historical records indicate dense and diverse assemblages of unionid mussels (Bivalvia: Unionidae) in a variety of aquatic communities, but the potential structuring role of competitive interactions among these organisms has not been adequately examined. We report here the result...

  5. Preliminary Investigations of Biofouling of Ships’ Hulls: Non-Indigenous Species Investigations in the Columbia River

    DTIC Science & Technology

    2006-04-01

    Cutter Chlorophyta Chlorophyta spp P Cirrepedia Balanus amphitrite P/S Bivalvia Ostreidae sp A P/S Ischadium sp? S Bryozoa Watersipora...Balanus improvisus P/S Hydrozoa Unidentified hydroid B P/S Bryozoa Fredericella indica P Amphipoda Americorophium spp P/S Passenger Chlorophyta...Chlorophyta spp P Tanker Chlorophyta Chlorophyta spp P Cirrepedia Megabalanus sp P Bivalvia Ostreidae sp B P/S Mytilus sp A S Bryozoa

  6. Possibility for using of two Paulownia lines as a tool for remediation of heavy metal contaminated soil.

    PubMed

    Tzvetkova, Nikolina; Miladinova, Kamelya; Ivanova, Katya; Georgieva, Teodora; Geneva, Marya; Markovska, Yuliana

    2015-01-01

    One-year-old two Paulownia lines (Ptomentosa x fortunei--TF 01 and R elongata x fortunei--EF 02) were grown, as pot experiment, in soil collected from the field of waste depository of Kremikovtzi ferrous metallurgical industry near Sofia. The soil was heavily polluted with Cd. Metals content (Ca, Mg, K, Na, Cd, Cu, Pb, Zn and Fe) in soil and its distribution in roots, stems and leaves of both lines was studied. The results showed that Ca and K accumulated more in stem, Mg, Na, Fe and Cd in root, while Pb, Cu and Zn in the leaves of both lines. The bloaccumulation factor (BF) and translocation factor (TF) were evaluated in order to determine the potential of plants in removing metals from contaminated soil. The BF for Fe, Pb, Cu and Zn in TF 01 line exceeded that of EF 02 line--5.6; 1.03; 1.20; 1.14 times, respectively. TF was higher in TF 01 line for Fe, Pb and Cd (6.0; 1.92 and 1.03, respectively), but not for Cu and Zn. The success of phytoremediation depends on plant growth and restricted distribution of heavy metals in shoots. Our results showed that stem length and total leaf area of Paulownia elongata x fortunei were higher than Paulownia tomentosa x fortuneibut BF for Cu and Zn and TF for Pb was less. BF for Cd was 1.7 times higher and TF for Zn was 1.03 times higher in Paulownia elongata x fortunei. Selected two lines (P. tomentosa x fortunei--TF 01 and P elongataxfortunei--EF02) were accumulators of Cu, Zn and Cd. Paulownia tomentosax fortunei accumulated more Pb and Zn in aboveground parts, while Paulownia elongata x fortunei--accumulated Zn only. These lines proved to be a promising species for phytoremediation of heavy metal polluted soils due to high biomass productivity.

  7. First report on the occurrence of the comb pen shell, Atrina pectinata (Linnaeus, 1767) (Bivalvia: Pinnidae) in Ulleungdo Island in the East Sea: Ecology and molecular identification of the species using COI gene sequence

    NASA Astrophysics Data System (ADS)

    Yang, Hyun-Sung; Kang, Hyun-Sil; Park, Heung-Sik; Noh, Choong Hwan; Jeong, Eui-Young; Choi, Kwang-Sik

    2015-12-01

    Pen shell is one of the largest marine bivalves inhabiting shallow subtidal soft bottoms in the west Pacific and Indian Oceans. In Korea, the comb pen shell Atrina pectinata fisheries has been established on the south and west coasts. Recently, a pen shell population has been discovered from a subtidal sand flat (25-30 m depth) in Ulleungdo Island located in the East Sea of Korea, suggesting a potential shellfish resource in this area. In the present study, we first surveyed the population density and size of the unique pen shell using SCUBA, and identified the pen shell to species level using mitochondrial cytochrome oxidase I gene (COI) sequence. An underwater survey carried out from July to September 2013 revealed that populations of pen shell patched on subtidal sand flat at a depth of 20-25 m. Grain size analysis indicated that sand particles accounted for 99% of the 600 × 700 m sand flat. The underwater survey also indicated that density of the pen shell ranged between 6-19 ind/m2, with a mean of 11 ind/m2. Shell height (i.e. longest axis of the shell) of the pen shell on the sand flat varied between 17.2 cm to 28.8 cm, with a mean of 25.1 cm, and the age was estimated to range between 1.5-7.5 yrs, with a mean of 5 yr. COI DNA sequence obtained from the pen shell in this study showed 98.9-99.2% similarity to Atrina pectinata (Linnaeus 1767) reported from Japan. In the cluster analysis, the COI DNA sequence of the pen shells from Ulleungdo Island was grouped with A. pectinata reported from Japan and China, indicating that the pen shell discovered in this study was A. pectinata, commonly distributed on the west and south coasts of Korea.

  8. The biology and functional morphology of Coralliophaga lithophagella (Bivalvia: Arcticoidea: Trapezidae): An abyssate, deep-water, nestler from the Açores. With comparative notes on the estuarine Trapezium liratum from Hong Kong

    NASA Astrophysics Data System (ADS)

    Morton, Brian

    2014-04-01

    Coralliophaga lithophagella is a nestler of basaltic rocks in the deeper waters (˜57-360 m) of the Açores and of shallower limestone karst in the Mediterranean where it predominately occurs in empty lithophagine burrows. In the Açores, because of low oceanic productivity and the basaltic, un-boreable, substratum, C. lithophagella is but 50% the shell length of continental European conspecifics and the shell's postero-dorsal margin is growth elevated to enhance particle capture. This is also achieved with relatively enormous ctenidia, minute labial palps and a simplified intestine. Unusually amongst the Trapezidae, C. lithophagella is abyssate and the foot is reduced. Also atypically, and during ontogeny, the shell enlarges postero-dorsally to facilitate particle capture. Anatomical features of the representatives of the constituent genera of the Trapezidae are compared one with another and with Arctica islandica (Arcticidae), the constituent families of the Arcticoidea. It is concluded that the Trapezidae constitutes a discrete clade of epibenthic nestlers, possibly descended from an endobenthic arcticoid ancestor, and showing a trend towards a reduction in shell and hinge complexity. The status of Fluviolanatus subtorta with mantle margins filled with single-celled algae and putatively assigned to the Trapezidae, awaits molecular confirmation.

  9. Genetic Diversity of the Biofilm Covering Montacuta ferruginosa (Mollusca, Bivalvia) as Evaluated by Denaturing Gradient Gel Electrophoresis Analysis and Cloning of PCR-Amplified Gene Fragments Coding for 16S rRNA†

    PubMed Central

    Gillan, David C.; Speksnijder, Arjen G. C. L.; Zwart, Gabriel; De Ridder, Chantal

    1998-01-01

    The shell of the bivalve Montacuta ferruginosa, a symbiont living in the burrow of an echinoid, is covered with a rust-colored biofilm. This biofilm includes different morphotypes of bacteria that are encrusted with a mineral rich in ferric ion and phosphate. The aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria. Also, the possible roles of the microorganisms in the processes of mineral deposition within the biofilm, as well as their impact on the biology of the bivalve, were assessed by phenotypic inference. The genetic diversity was determined by denaturing gradient gel electrophoresis (DGGE) analysis of short (193-bp) 16S ribosomal DNA PCR products obtained with primers specific for the domain Bacteria. This analysis revealed a diverse consortium; 11 to 25 sequence types were detected depending on the method of DNA extraction used. Individual biofilms analyzed by using the same DNA extraction protocol did not produce identical DGGE profiles. However, different biofilms shared common bands, suggesting that similar bacteria can be found in different biofilms. The phylogenetic affiliations of the sequence types were determined by cloning and sequencing the 16S rRNA genes. Close relatives of the genera Pseudoalteromonas, Colwellia, and Oceanospirillum (members of the γ-Proteobacteria lineage), as well as Flexibacter maritimus (a member of the Cytophaga-Flavobacter-Bacteroides lineage), were found in the biofilms. We inferred from the results that some of the biofilm bacteria could play a role in the mineral formation processes. PMID:9726898

  10. Freshwater Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites Within the 9-Foot Navigation Channel Project for the St. Paul District, United States Army Corps of Engineers, 1977 - 1979. Volume I. Text.

    DTIC Science & Technology

    1980-09-10

    Platyhelminthes : Trematoda). This point somewhat coun- ters the idea of this population’s viability. Partially reviewed by Fuller (1974), Nearctic...infestation with flukes, a group of parasitic flatworms ( Platyhelminthes : Trematoda). UM -- Upper Mississippi. Unionicolidae, unionicolid -- the

  11. Freshwater Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites Within the 9-Foot Navigation Channel Project for the St. Paul District, United States Army Corps of Engineers, 1977 - 1979. Volume II. Appendices.

    DTIC Science & Technology

    1980-09-10

    111 16. Vermillion River 15 >2 1)9, _: L Hastings Small Boat Harbor 16 13 -,2 IS. Prescott 17 !14 199, 19. Pine Coulee 13 15 0. Truedaie Slough 19 116...Iowa Darter E. nigrum Rafinesque, Johnny Darter Perca flavescens (Mitchill), Yellow Perch Stizostedion e-avadense (Smith), Sauger Family Sciaenidae...brailing Brail runs: positive, 0 ; negative, 14 ;total, 14 Number of square ifeet brailed: 70,000 Exhibit 15 16. Vermillion River \\Tusc’ Tha, xni

  12. Fresh-Water Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites within the 9-Foot Channel Navigation Project on Behalf of the U.S. Army.

    DTIC Science & Technology

    1978-06-16

    8217. Rational candidates for glochidial host( s ) of the Spectacle Case are, for example, 6 . 61 -_ _ ’ , , . - - - - one or more developmental stages of a...U) JUN 78 S L FULLER UNCLASSIFIED 78-33 NL 1.25 III 111112.5 N~ 2 PHOTOGRAPH THIS SHEET LEVEL of Nfafura.( Sc.enes 0*ORY :A; 41421467.:iw. ofL iw.(y...GOVTnr ACESONNS. RCNTT ORAGRANT NUMERe . PEFRMIN ORAIAINNMEASADES1. TP ORMELEMET& PEROOECTOVTASK at. COeRlLce ie ihnte9- tcanl S EFRING OFFCNAMGN DDESI

  13. Rapid, effective DNA isolation from Osmanthus via alkaline lysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Osmanthus contains many popular ornamental species including fragrant tea-olive (O. fragrans) and Fortune’s tea-olive (Osmanthus x fortunei). Growers seek improved Osmanthus varieties; however, few molecular tools exist for this genus. Furthermore, the variability of leaf structure and pre...

  14. Complete Genome Sequence of Paenibacillus polymyxa CF05, a Strain of Plant Growth-Promoting Rhizobacterium with Elicitation of Induced Systemic Resistance.

    PubMed

    Lei, Mengying; Lu, Peng; Jin, Liping; Wang, Yan; Qin, Jialing; Xu, Xi; Zhang, Liqin; Wang, Yongjun

    2015-04-16

    Paenibacillus polymyxa CF05 is a Gram-positive rod-shaped bacterium isolated from the interior of an ancient tree, Cryptomeria fortunei, in China. This bacterium displays potent biocontrol effects against certain soil-borne diseases and the elicitation of induced systemic resistance in tomatoes. Here, we report the complete genome sequence of P. polymyxa CF05.

  15. Nematotoxicity of drupacine and a Cephalotaxus alkaloid preparation against the plant-parasitic nematodes Meloidogyne incognita and Bursaphelenchus xylophilus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species of Cephalotaxus (the plum yews) produce nematotoxic compounds of unknown identity. Consequently, bioassay-guided fractionation was employed to identify the compound(s) in Cephalotaxus fortunei twigs and leaves with activity against plant-parasitic nematodes. A crude alkaloid extract, particu...

  16. Shell biofilm nitrification and gut denitrification contribute to emission of nitrous oxide by the invasive freshwater mussel Dreissena polymorpha (zebra mussel).

    PubMed

    Svenningsen, Nanna B; Heisterkamp, Ines M; Sigby-Clausen, Maria; Larsen, Lone H; Nielsen, Lars Peter; Stief, Peter; Schramm, Andreas

    2012-06-01

    Nitrification in shell biofilms and denitrification in the gut of the animal accounted for N(2)O emission by Dreissena polymorpha (Bivalvia), as shown by gas chromatography and gene expression analysis. The mussel's ammonium excretion was sufficient to sustain N(2)O production and thus potentially uncouples invertebrate N(2)O production from environmental N concentrations.

  17. Draft Environmental Impact Statement. Guam Cleanup of Uruno Beach

    DTIC Science & Technology

    1987-02-01

    Artocarpus altilus, Ficus spp., Agilaia mariannensis, Guamia mariannae, Eugenia reinwardtiana, Premna obtusifolia, Melanolepis multiglandulosa...consisted of dwarfed forms of the limestone forest elements but favor certain species such as Mammea odorata and Ficus tinctoria, along with emerged limestone...ecliiritus (Jaeger) HOLLUSCA W-ohidschia Arjqs (Jaeger) Bivalvia . B. bivittata (Mitsukuri) Tridacna maxima (Roding) Roloftui (ITalodeima) atra Jaeger

  18. Determination of shell deposition rates of Arctica islandica from the New York Bight using natural /sup 228/Ra and /sup 228/Th and bomb-produced /sup 14/C

    SciTech Connect

    Turekian, K.K.; Cochran, J.K.; Nozaki, Y.; Thompson, I.; Jones, D.S.

    1982-01-01

    Shell deposition rates of specimens of Arctica islandica (Mollusca: Bivalvia) from the New York Bight were determined using natural /sup 228/Ra and /sup 228/Th and bomb /sup 14/C. The specimens from deep (>55 m) offshore waters show annual growth banding. A shell obtained from the inner bight at <30-m depth seems to be younger than indicated by band counting.

  19. Environmental Habitat Conditions Associated with Freshwater Dreissenids

    DTIC Science & Technology

    2010-12-01

    of Dreissenid mussel in the Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 49:1501-1506. McMahon, R. F. 1991. Mollusca : Bivalvia...In The Mollusca . Vol. 6, Ecology, ed. W. D. Russell- Hunter, 463-503. Orlando, FL: Academic Press, Inc. Schneider, D. W., S. P. Madon, J. A. Stoeckel

  20. Predicting the Potential for Invasive Species Establishment by Using Environmental Tolerance Data

    DTIC Science & Technology

    2010-05-01

    ERDC/TN ANSRP-10-2 May 2010 1 Predicting the Potential for Invasive Species Establishment by Using Environmental Tolerance Data by Judy F...world where common carp have established , thus increasing the likelihood that the species would become estab- lished and widespread throughout the...Carp), Limnoperna fortunei (Asian mussel) and Potamopyrgus antipodarum (New Zealand mud snail) (Chen et al. 2007; Loo et al. 2007). A GARP model was

  1. Growth variation of Paulownia Sieb. and Zucc. species and origins at the nursery stage in Kastamonu-Turkey.

    PubMed

    Ayan, S; Sivacioglu, A; Bilir, N

    2006-07-01

    The present study was carried out on Paulownia tomentosa (6), Paulownia elongate (4), Paulownia fortunei (5) and Paulownia fortunei x tomentosa (1) origins at Kastamonu Forest Nursery. The seedling height growth (SH), root collar diameter (RCD), dry root percentage (DRP) and seedling percentage (SP) of one-year old seedlings of the origins were studied for comparing growth performance of the species and origins and discussing for guidance to field stage based on nursery stage. As a result, P. tomentosa x fortunei hybrid has the highest SH (72.62 cm) among the used species. Significant difference was determined among the origins as to the SH and DRP. The maximum SH were determined for P. tomentosa Beijing-Daxin (81.32 cm) and P. elongata Beijing-Daxin (80.76 cm) origins. The maximum DRP were determined for P. tomentosa Anhui-Tongling (77%) origin. There were no significant differences based on RCD and SP among the species and the origins. Among the parents, there were important diversities for SH and RCD. As a final remark, observations and evaluations of the Paulownia studies should be included with the clonal variation for further studies because of the observed growth variations within the population.

  2. Effects of salinity on the photosynthetic apparatus of two Paulownia lines.

    PubMed

    Stefanov, Martin; Yotsova, Ekaterina; Rashkov, Georgi; Ivanova, Katya; Markovska, Yuliana; Apostolova, Emilia L

    2016-04-01

    The effects of soil salinity on the functional activity of photosynthetic apparatus and pigment composition of two Paulownia lines (Paulownia tomentosa x fortunei and Paulownia elongata x elongata) were investigated. PAM chlorophyll fluorescence measurements revealed that salinity leads to: (i) an increase of the photochemical quenching coefficient (qP) and the linear electron transport rate (ETR) in both lines of Paulownia, while the maximum quantum yield of the primary photochemistry of PSII in the dark adapted state (Fv/Fm) was unaffected; (ii) improved the efficiency of the photochemical energy conversion (ФPSII); (iii) an impact on the chlorophyll fluorescence decrease ratio (RFd), which correlates to the net CO2 assimilation rate; (iv) an impact on [Formula: see text] reoxidation. The analysis of the kinetics of P700(+) reduction upon turning off far-red irradiation revealed that salinization lead to a delay of the cyclic electron transport around PSI in both studied lines as the effect on this process is more pronounced in P. tomentosa x fortunei than in (in comparison with) P. elongata x elongata. The present experimental results suggested high salt tolerance of the studied lines Paulownia, but P. tomentosa x fortunei is more tolerant to salinity than P. elongata x elongata. Molecular mechanisms involved in the Paulownia response to the soil salinity are discussed.

  3. Pursuing the quest for better understanding the taxonomic distribution of the system of doubly uniparental inheritance of mtDNA

    PubMed Central

    Gusman, Arthur; Lecomte, Sophia; Stewart, Donald T.; Passamonti, Marco

    2016-01-01

    There is only one exception to strict maternal inheritance of mitochondrial DNA (mtDNA) in the animal kingdom: a system named doubly uniparental inheritance (DUI), which is found in several bivalve species. Why and how such a radically different system of mitochondrial transmission evolved in bivalve remains obscure. Obtaining a more complete taxonomic distribution of DUI in the Bivalvia may help to better understand its origin and function. In this study we provide evidence for the presence of sex-linked heteroplasmy (thus the possible presence of DUI) in two bivalve species, i.e., the nuculanoid Yoldia hyperborea(Gould, 1841)and the veneroid Scrobicularia plana(Da Costa,1778), increasing the number of families in which DUI has been found by two. An update on the taxonomic distribution of DUI in the Bivalvia is also presented. PMID:27994972

  4. Food habits and seasonal variation of stomach contents of tongue sole Cynoglossus semilaevis (Günther) in the Bohai Sea

    NASA Astrophysics Data System (ADS)

    Dou, Shuozeng

    1993-03-01

    Examination of the food habits and seasonal variation of the stomach contents of adult tongue sole, Cynoglossus semilaevis (Günther) taken in July 1982 July 1983 from Laizhou Bay and the Huanghe River estuary of the Bohai Sea showed crustacea, bivalvia and small fishes comprised the main prey. Invertebrates such as polychaeta, cephalopoda, gastropoda, echinodermata and actiniaria were also intermittently found in them. They intensively fed all the year found (monthly feeding rate of over 80%). The main food items were Alpheus japonica, Alpheus distinguendus. Oratosquilla oratoria, Eucrate crenata and Carcinoplax vestitus, etc. In summer and autumn, the portion of bivalvia such as Cultellus attenuatus and Musculus senhousei increased steadily. From summer to winter, a stable proportion of small fishes such as Rhinogobius pflaumi and Setipinna taty was in the diet.

  5. Pursuing the quest for better understanding the taxonomic distribution of the system of doubly uniparental inheritance of mtDNA.

    PubMed

    Gusman, Arthur; Lecomte, Sophia; Stewart, Donald T; Passamonti, Marco; Breton, Sophie

    2016-01-01

    There is only one exception to strict maternal inheritance of mitochondrial DNA (mtDNA) in the animal kingdom: a system named doubly uniparental inheritance (DUI), which is found in several bivalve species. Why and how such a radically different system of mitochondrial transmission evolved in bivalve remains obscure. Obtaining a more complete taxonomic distribution of DUI in the Bivalvia may help to better understand its origin and function. In this study we provide evidence for the presence of sex-linked heteroplasmy (thus the possible presence of DUI) in two bivalve species, i.e., the nuculanoid Yoldia hyperborea(Gould, 1841)and the veneroid Scrobicularia plana(Da Costa,1778), increasing the number of families in which DUI has been found by two. An update on the taxonomic distribution of DUI in the Bivalvia is also presented.

  6. Assessment of Zebra Mussel (Dreissena Polymorpha) Infestation Risk Using GIS for Water Basins in the North-West Bulgaria

    DTIC Science & Technology

    2007-01-22

    August 9-13, 2004, San Diego, California, 12 pp. Angelov, A., 2000. Catalogus faunae bulgaricae. 4. Mollusca : Gastropoda et Bivalvia aquae dulcis...distribution of freshwater Mollusca in Bulgaria. Annuaire de l’Universite de Sofia. Faculte Physico-Mathematique 43 (3): 33- 54. (In Bulgarian, English summary...Dreissena polymorpha Pallas ( Mollusca ) in the energy budget of Lake Esrom, Denmark. Verh. Int. Ver. Limnol., 24: 621-625. Hayward, D., & E. Estevez

  7. Complete mitochondrial genome of hydrothermal vent clam Calyptogena magnifica.

    PubMed

    Liu, Helu; Cai, Shanya; Zhang, Haibin; Vrijenhoek, Robert C

    2016-11-01

    The mitochondrial genome of the hydrothermal vent clam Calyptogena magnifica (Bivalvia, Veneroida, Vesicomyidae) is reported for the first time in this study. The total length of its mitochondrial genome is 19 738 bp with overall GC content of 31.6%. The mitochondrial genome consists of 36 genes, including 13 protein-coding sequences, 2 rRNA and 21 tRNA genes. Two distinct repeat motifs are located between tRNA(Trp) and ND6.

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

    NASA Astrophysics Data System (ADS)

    de Vooys, C. G. N.

    2002-02-01

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

  9. The Calyptogena magnifica chemoautotrophic symbiont genome

    SciTech Connect

    Newton, I.L.; Woyke, T.; Auchtung, T.A.; Dilly, G.F.; Dutton,R.J.; Fisher, M.C.; Fontanez, K.M.; Lau, E.; Stewart, F.J.; Richardson,P.M.; Barry, K.W.; Saunders, E.; Detter, J.C.; Wu, D.; Eisen, J.A.; Cavanaugh, C.M.

    2007-03-01

    Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.

  10. Disturbance of shallow marine soft-bottom environments and megabenthos assemblages by a huge tsunami induced by the 2011 M9.0 Tohoku-Oki earthquake.

    PubMed

    Seike, Koji; Shirai, Kotaro; Kogure, Yukihisa

    2013-01-01

    Huge tsunami waves associated with megathrust earthquakes have a severe impact on shallow marine ecosystems. We investigated the impact of a tsunami generated by the 2011 M9.0 Tohoku-Oki earthquake on the seafloor and large benthic animals in muddy and sandy ria coasts (Otsuchi and Funakoshi bays) in northeastern Japan. We conducted underwater field surveys using scuba equipment in water depths of <20 m before the tsunami (September 2010) and after the tsunami (September 2011 and September 2012). During the study period, episodic changes in topography and grain-size composition occurred on the seafloor of the study area. Megabenthos sampling revealed a distinct pattern of distribution succession for each benthic species. For example, the protobranch bivalve Yoldia notabilis (Bivalvia: Nuculanidae) and the heterodont bivalve Felaniella usta (Bivalvia: Ungulinidae) disappeared after the tsunami event, whereas the distribution of the venus clam Gomphina melanaegis (Bivalvia: Veneridae) remained unchanged. In addition, the patterns of succession for a single species, such as the giant button top shell Umbonium costatum (Gastropoda: Trochidae) and the heart urchin Echinocardium cordatum (Echinoidea: Loveniidae), varied between the two bays studied. Our data also show that reestablishment of some benthic animal populations began within 18 months of the tsunami disturbance.

  11. Disturbance of Shallow Marine Soft-Bottom Environments and Megabenthos Assemblages by a Huge Tsunami Induced by the 2011 M9.0 Tohoku-Oki Earthquake

    PubMed Central

    Seike, Koji; Shirai, Kotaro; Kogure, Yukihisa

    2013-01-01

    Huge tsunami waves associated with megathrust earthquakes have a severe impact on shallow marine ecosystems. We investigated the impact of a tsunami generated by the 2011 M9.0 Tohoku-Oki earthquake on the seafloor and large benthic animals in muddy and sandy ria coasts (Otsuchi and Funakoshi bays) in northeastern Japan. We conducted underwater field surveys using scuba equipment in water depths of <20 m before the tsunami (September 2010) and after the tsunami (September 2011 and September 2012). During the study period, episodic changes in topography and grain-size composition occurred on the seafloor of the study area. Megabenthos sampling revealed a distinct pattern of distribution succession for each benthic species. For example, the protobranch bivalve Yoldia notabilis (Bivalvia: Nuculanidae) and the heterodont bivalve Felaniella usta (Bivalvia: Ungulinidae) disappeared after the tsunami event, whereas the distribution of the venus clam Gomphina melanaegis (Bivalvia: Veneridae) remained unchanged. In addition, the patterns of succession for a single species, such as the giant button top shell Umbonium costatum (Gastropoda: Trochidae) and the heart urchin Echinocardium cordatum (Echinoidea: Loveniidae), varied between the two bays studied. Our data also show that reestablishment of some benthic animal populations began within 18 months of the tsunami disturbance. PMID:23762365

  12. Impact tolerance in mussel thread networks by heterogeneous material distribution

    NASA Astrophysics Data System (ADS)

    Qin, Zhao; Buehler, Markus J.

    2013-07-01

    The Mytilidae, generally known as marine mussels, are known to attach to most substrates including stone, wood, concrete and iron by using a network of byssus threads. Mussels are subjected to severe mechanical impacts caused by waves. However, how the network of byssus threads keeps the mussel attached in this challenging mechanical environment is puzzling, as the dynamical forces far exceed the measured strength of byssus threads and their attachment to the environment. Here we combine experiment and simulation, and show that the heterogeneous material distribution in byssus threads has a critical role in decreasing the effect of impact loading. We find that a combination of stiff and soft materials at an 80:20 ratio enables mussels to rapidly and effectively dissipate impact energy. Notably, this facilitates a significantly enhanced strength under dynamical loading over 900% that of the strength under static loading.

  13. Impact tolerance in mussel thread networks by heterogeneous material distribution.

    PubMed

    Qin, Zhao; Buehler, Markus J

    2013-01-01

    The Mytilidae, generally known as marine mussels, are known to attach to most substrates including stone, wood, concrete and iron by using a network of byssus threads. Mussels are subjected to severe mechanical impacts caused by waves. However, how the network of byssus threads keeps the mussel attached in this challenging mechanical environment is puzzling, as the dynamical forces far exceed the measured strength of byssus threads and their attachment to the environment. Here we combine experiment and simulation, and show that the heterogeneous material distribution in byssus threads has a critical role in decreasing the effect of impact loading. We find that a combination of stiff and soft materials at an 80:20 ratio enables mussels to rapidly and effectively dissipate impact energy. Notably, this facilitates a significantly enhanced strength under dynamical loading over 900% that of the strength under static loading.

  14. A comparative study of the anti-settlement properties of mytilid shells.

    PubMed

    Bers, A V; Prendergast, G S; Zürn, C M; Hansson, L; Head, R M; Thomason, J C

    2006-03-22

    Marine organisms have evolved defence mechanisms to prevent epibiosis. This study investigated the anti-settlement properties of natural periostracal microtopographies of two mytilid species, Mytilus edulis (from North, Baltic and White Seas) and Perna perna (from the SW Atlantic). Resin replicas of shells were exposed to cyprids of the barnacle Semibalanus balanoides. Replicas with intact isotropic microtopographies and smooth controls were much less fouled than roughened anisotropic surfaces. This indicates that in both M. edulis and P. perna the periostracum possesses a generic anti-settlement property, at least against S. balanoides cyprids, which is not regionally adapted. Such a potential globally effective anti-settlement mechanism possibly contributes to the invasive success of Mytilidae.

  15. Spermatogenesis of the green-lipped mussel Perna viridis with dual patterns of acrosome and tail development in spermatids

    NASA Astrophysics Data System (ADS)

    Reunov, A. A.; Au, D. W. T.; Wu, R. S. S.

    1999-08-01

    Spermatogenesis in the mussel Perna viridis was studied by electron microscopy. Results demonstrated that cytological development in spermatogonia and spermatocytes was similar to that previously described in other Mytilidae. Acrosome formation began with the arising of proacrosomal vesicles in spermatogonia. The abundance of proacrosomal vesicles increased in spermatocytes, which were flagellated. However, during spermiogenesis, dual patterns of acrosome development as well as flagellum development could be found among spermatids in a male gonad. The two lines of acrosome formation in spermatids ultimately gave rise to morphologically similar acrosomes. The two lines of flagellum development in spermatids resulted in the formation of sperm cells with either a typically posteriorly directed tail or an anteriorly directed tail.

  16. Electron Paramagnetic Resonance Study of Defects in γ-irradiated Marine Mussel (Mytilus galloprovincialis) and Scallop (Pecten jacobaeus) Shells

    NASA Astrophysics Data System (ADS)

    Köseoğlu, R.; Köksal, F.; Birey, M.

    2004-11-01

    EPR studies have been performed on some gamma-irradiated marine mussels (Mytilus galloprovincialis) and scallops (Pecten jacobaeus) from the families of Mytilidae and Pectinidae, respectively. Before γ-irradiation, the EPR lines of Mytilus galloprovincialis indicated the existence of Mn2+ ions, which were not observed in the powders of scallop shells. γ -irradiation induced defects in powders of Mytilus galloprovincialis shells, were attributed to orthorhombic CO-3 , axial CO3-3 , orthorhombic CO-2 , freely rotating CO-2 , freely rotating SO-2 , axial SO-3 , isotropic PO2-4 and organic free radicals. γ -irradiation induced defects in powders of Pecten jacobaeus shells were attributed to orthorhombic CO-3 , axial CO3-3 , orthorhombic CO-2 , freely rotating CO-2 , freely rotating SO-2 , and axial SO-3 free radicals. The EPR parameters of the free radicals were compared with literature data on similar defects

  17. The Complete Female- and Male-Transmitted Mitochondrial Genome of Meretrix lamarckii

    PubMed Central

    Passamonti, Marco

    2016-01-01

    Bivalve mitochondrial genomes show many uncommon features, like additional genes, high rates of gene rearrangement, high A-T content. Moreover, Doubly Uniparental Inheritance (DUI) is a distinctive inheritance mechanism allowing some bivalves to maintain and transmit two separate sex-linked mitochondrial genomes. Many bivalve mitochondrial features, such as gene extensions or additional ORFs, have been proposed to be related to DUI but, up to now, this topic is far from being understood. Several species are known to show this unusual organelle inheritance but, being widespread only among Unionidae and Mytilidae, DUI distribution is unclear. We sequenced and characterized the complete female- (F) and male-transmitted (M) mitochondrial genomes of Meretrix lamarckii, which, in fact, is the second species of the family Veneridae where DUI has been demonstrated so far. The two mitochondrial genomes are comparable in length and show roughly the same gene content and order, except for three additional tRNAs found in the M one. The two sex-linked genomes show an average nucleotide divergence of 16%. A 100-aminoacid insertion in M. lamarckii M-cox2 gene was found; moreover, additional ORFs have been found in both F and M Long Unassigned Regions of M. lamarckii. Even if no direct involvement in DUI process has been demonstrated so far, the finding of cox2 insertions and supernumerary ORFs in M. lamarckii both strengthens this hypothesis and widens the taxonomical distribution of such unusual features. Finally, the analysis of inter-sex genetic variability shows that DUI species form two separate clusters, namely Unionidae and Mytilidae+Veneridae; this dichotomy is probably due to different DUI regimes acting on separate taxa. PMID:27083010

  18. Microsatellite markers in Paulownia kawakamii (Scrophulariaceae) and cross-amplification in other Paulownia species.

    PubMed

    Wang, H W; Duan, J M; Zhang, P; Cheng, Y Q; Wu, J W; Wang, G Z

    2013-09-19

    Paulownia kawakamii is a fast-growing timber tree. In this study, 21 primer sets were developed using an enriched genomic library. The genetic diversity was measured in one P. kawakamii population. The number of alleles per locus ranged from 2 to 19. The observed and expected heterozygosities varied from 0.158 to 0.842 (mean = 0.421) and from 0.376 to 0.952 (mean = 0.771), respectively. All 21 loci were also polymorphic in closely related species (P. tomentosa, P. elongata, and P. fortunei). The described markers will be useful in future population genetic studies and molecular breeding of these Paulownia species.

  19. Mortality through ontogeny of soft-bottom marine invertebrates with planktonic larvae

    NASA Astrophysics Data System (ADS)

    Pedersen, Troels Møller; Hansen, Jørgen L. S.; Josefson, Alf B.; Hansen, Benni W.

    2008-09-01

    The present survey covers one spawning season of marine benthic invertebrates in a large geographical area, the inner Danish waters, and includes a wide range of habitats with steep salinity and nutrient load gradients. The loss ratios of soft-bottom marine invertebrates from one development stage to the next is calculated based on average abundances of pelagic larvae, benthic post-larvae and adults of Bivalvia, Gastropoda, Polychaeta and Echinodermata, with planktonic development. This gives a rough estimate of the larval and post-larval mortality. Loss ratios between post-larvae stage and adult stage (post-larval mortality) varies from 3:1 to 7:1 (71.2-84.9%) and loss ratios between larvae and post-larvae (larval mortality) and between larvae and adult, ranging from 7:1 to 42:1 (85.2-97.6%) and from 45:1 to 210:1 (97.8-99.5%), respectively. The results show a remarkable unity in loss ratios (mortality) between the mollusc taxa (Bivalvia and Gastropoda) at the phylum/class level. This similarity in loss ratios among the mollusc taxa exhibiting the same developmental pathways suggests that the mortality is governed by the same biotic and abiotic factors. Larval mortality is estimated to range from 0.10 d - 1 to 0.32 d - 1 for Bivalvia and ranging from 0.09 d - 1 to 0.23 d - 1 for Polychaeta. The species loss ratios combined with specific knowledge of the reproduction cycles give estimated loss ratios (mortality) between the post-larvae and the adult stage of 25:1 and 14:1 for the bivalves Abra spp. and Mysella bidentata. For the polychaete Pygospio elegans the loss ratio (larval mortality) between the larvae and the post-larval stage is 154:1 and between the post-larvae and the adult stage 41:1. For Pholoe inornata the loss ratio between post-larvae and adults is 7:1. The present results confirm that the larval stage, metamorphosis and settlement are the critical phase in terms of mortality in the life cycle for Bivalvia. Assuming steady state based on actual

  20. First report of intramolluscan stages of a gorgoderid digenean from a marine bivalve.

    PubMed

    Bott, Nathan J; Cribb, Thomas H

    2005-08-01

    A survey of bivalves from Heron Island on the Great Barrier Reef, Australia, revealed a novel digenean infection in Lioconcha castrensis (Bivalvia: Veneridae). The cercaria has oral and ventral suckers, a dorsoventrally orientated stylet embedded in the oral sucker, penetration glands, and a large tail that is inflated at its base. This morphology is broadly consistent with that of previously described gorgoderid cercariae. Partial large subunit ribosomal RNA gene (D1-D3 domains) was sequenced and aligned with sequences from other gorgoderids and related families. Phylogenetic analysis also suggests that the species belongs to the Gorgoderinae. To our knowledge, this is the first report of a gorgoderid from a marine bivalve.

  1. Development and characterization of 16 polymorphic microsatellite markers from Taiwan cow-tail fir, Keteleeria davidiana var. formosana (Pinaceae) and cross-species amplification in other Keteleeria taxa

    PubMed Central

    2014-01-01

    Background Keteleeria davidiana var. formosana (Pinaceae), Taiwan cow-tail fir, is an endangered species listed on the IUCN Red List of Threatened Species and only two populations remain, both on the Taiwan Island. Sixteen polymorphic microsatellite loci were developed in an endangered and endemic gymnosperm species, Keteleeria davidiana var. formosana, and were tested in an additional 6 taxa, K. davidiana var. calcarea, K. davidiana var. chienpeii, K. evelyniana, K. fortunei, K. fortunei var. cyclolepis, and K. pubescens, to evaluate the genetic variation available for conservation management and to reconstruct the phylogeographic patterns of this ancient lineage. Findings Polymorphic primer sets were developed from K. davidiana var. formosana using the modified AFLP and magnetic bead enrichment method. The number of alleles ranged from 3 to 16, with the observed heterozygosity ranging from 0.28 to 1.00. All of the loci were found to be interspecifically amplifiable. Conclusions These polymorphic and transferable loci will be potentially useful for future studies that will focus on identifying distinct evolutionary units within species and establishing the phylogeographic patterns and the process of speciation among closely related species. PMID:24755442

  2. Estuarine Habitat Assessment for Construction of a Submarine Transmission Line

    NASA Astrophysics Data System (ADS)

    Hamouda, Amr Z.; Abdel-Salam, Khaled M.

    2010-07-01

    The present paper describes a submarine survey using the acoustic discrimination system QTC VIEW (Series V) as an exploratory tool to adjust final route alignment of a new pipeline. By using acoustic sound survey as an exploratory tool described in this paper to adjust final route alignment of a new pipeline to minimize the environmental impact caused and ultimately to avoid any mitigation measures. The transmission pipeline extended from the shore line of Abu-Qir Bay, on the Mediterranean Sea in Egypt, out to 70 nautical miles at sea (60 m water depth). Four main surface sediment types were defined in the study area, namely fine sand, silty sand, silt and clay. Results of the acoustic classification revealed four acoustic classes. The first acoustic class corresponded to fine sand, absence of shell debris and very poor habitats characteristics. The second acoustic class is predominant in the study area and corresponds to the region occupied by silt. It is also characterized by intermediate diversity of macrobenthic invertebrate community which is mainly characterized by polychaeta. The third acoustic class is characterized by silt to silty clay. It is characterized by a high diversity of macrobenthic invertebrate community which is mainly polychaeta with an intermediate diversity of gastropoda and bivalvia. The final acoustic class is characterized by clay and high occurrence of shell debris of gastropoda, bivalvia and polychaeta.

  3. Are flatfish nursery grounds richer in benthic prey?

    NASA Astrophysics Data System (ADS)

    Wouters, Noémie; Cabral, Henrique N.

    2009-08-01

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

  4. Density shift, morphological damage, lysosomal fragility and apoptosis of hemocytes of Indian molluscs exposed to pyrethroid pesticides.

    PubMed

    Ray, Mitali; Bhunia, Anindya Sundar; Bhunia, Niladri Sekhar; Ray, Sajal

    2013-08-01

    Bellamya bengalensis (Gastropoda: Prosobranchia) and Lamellidens marginalis (Bivalvia: Eulamellibranchiata) are the molluscs of Indian freshwater ecosystem and important biological resources. These edible species bear economical, ecological, nutritional and medicinal importance. Natural habitat of these organisms is under the ecological threat of contamination by cypermethrin and fenvalerate, the common pyrethroid pesticides of India. Hemocytes are chief immunoeffector cells of molluscs which exhibit responsiveness against environmental toxins and perform diverse immunological functions including phagocytosis, encapsulation and cytotoxicity. Experimental exposure of cypermethrin and fenvalerate resulted in significant shift in density and morphological damage in hemocytes of B. bengalensis and L. marginalis respectively. Pyrethroid induced fragility and destabilization of hemocyte lysosomal membrane was recorded and proposed as an indication of toxin induced stress in molluscs. Apoptosis is an immunologically important cellular response which is modulated by environmental toxins. Pyrethroid exposure suppressed the physiological level of apoptosis and necrosis in hemocytes of B. bengalensis and L. marginalis indicating possible impairment of apoptosis mediated immunoprotection. Differential responses of B. bengalensis and L. marginalis hemocytes may be due to species specificity, toxin specificity, nonidentical immune strategies of Gastropoda and Bivalvia, specific habitat preference and related ecological niches.

  5. Hispaniolan Hemilophini (Coleoptera, Cerambycidae, Lamiinae)

    PubMed Central

    Lingafelter, Steven W.

    2013-01-01

    Abstract The Tribe Hemilophini (Lamiinae) is reviewed for Hispaniola and an identification key is provided. Fifteen species are now known from the island, including one new species of Adesmus (Adesmus fortunei from Pedernales and La Vega Provinces, Dominican Republic), one new species of Oedudes (Oedudes anulatus from Peravia and La Vega Provinces, Dominican Republic), and five new species of Calocosmus (Calocosmus contortus from San Cristóbal Province, Calocosmus punctatus from Peravia Province, Calocosmus rawlinsi from Elías Piña Province, Calocosmus robustus from La Vega Province, and Calocosmus thonalmus from La Altagracia Province, all in the Dominican Republic). Oedudes and Adesmus are new island and country records for Hispaniola and Dominican Republic, respectively. Calocosmus holosericeus Gahan is a new synonym of Calocosmus janus Bates. In addition to the new species, five new country records and four new island records are presented for Calocosmus. PMID:23653499

  6. [Seasonal release characteristics of Ca, Mg and Mn of foliar litter of six tree species in subtropical evergreen broadleaved forest].

    PubMed

    Ma, Zhi-liang; Gao, Shun; Yang, Wan-qin; Wu, Fu-zhong

    2015-10-01

    Seasonal release dynamics of Ca, Mg and Mn during decomposition of foliar litter of Pinus massoniana, Cryptomeria fortunei, Cunninghamia lanceolata, Cinnamomum camphora, Toona ciliate, and Quercus acutissima were investigated in subtropical evergreen broad-leaved forest employing the method of litterbag. After one-year decomposition, the release rates of Ca, Mg and Mn in foliar litter of the studied tree species ranged from -13.8% to 92.3%, from 4.0% to 64.8%, and from 41.6% to 81.1%, respectively. Ca dynamics in foliar litter of P. massoniana, C. camphora exhibited the pattern of accumulating early and releasing later, while that of the other four tree species showed direct release. Similarly, the dynamics of Mg released from foliar litter of C. camphora showed the pattern of accumulating early and then releasing, while that of the other five tree species exhibited continuous release. Meanwhile, the dynamics of Mn released from foliar litter of C. fortunei and T. ciliate exhibited early accumulation, and subsequent release, while that of the other four tree species showed continuous release. The releases of Ca, Mg and Mn in foliar litter were greatly influenced by seasonal rainfall, and varied with tree species. Furthermore, the rates and amounts of Ca, Mg and Mn released from foliar litter were higher in rainy season than in dry season. In conclusion, the initial nutrient concentrations and precipitation were two key factors influencing the release dynamics of Ca, Mg and Mn during decomposition of foliar litter in the subtropical evergreen broad-leaved forest.

  7. [Chemical properties and enzyme activities of rhizosphere and non-rhizosphere soils under six Chinese herbal medicines on Mt. Taibai of Qinling Mountains, Northwest China].

    PubMed

    Meng, Ling-Jun; Geng, Zeng-Chao; Yin, Jin-Yan; Wang, Hai-Tao; Ji, Peng-Fei

    2012-10-01

    This paper studied the chemical properties and enzyme activities of rhizosphere and non-rhizosphere soils in different habitats of six Chinese herbal medicines, including Pyrola decorata, Cephalotaxus fortunei, Polygonatum odoratum, Potentilla glabra, Polygonum viviparum, and Potentilla fruticosa, on the Mt. Taibai of Qinling Mountains. In the rhizosphere soils of the herbs, the contents of soil organic matter, total nitrogen, available nitrogen, and available phosphorus and the soil cation exchange capacity (CEC) were higher, presenting an obvious rhizosphere aggregation, and the soil enzyme activities also showed an overall stronger characteristics, compared with those in non-rhizosphere soils. The soil organic matter, total nitrogen, and total phosphorus contents in the rhizosphere soils had significant positive correlations with soil neutral phosphatase activity, and the soil CEC had significant positive correlations with the activities of soil neutral phosphatase and acid phosphatase. In the non-rhizosphere soils, the soil organic matter and total nitrogen contents had significant positive correlations with the activities of soil urease, catalase and neutral phosphatase, and the soil CEC showed a significant positive correlation with the activities of soil urease, catalase, neutral phosphatase and acid phosphatase. The comprehensive fertility level of the rhizosphere soils was higher than that of the non-rhizosphere soils, and the rhizosphere and non-rhizosphere soils of P. fruticosa, P. viviparum, and P. glabra had higher comprehensive fertility level than those of P. decorata, P. odoratum and C. fortunei. In the evaluation of the fertility levels of rhizosphere and non-rhizosphere soils under the six Chinese herbal medicines, soil organic matter content and CEC played important roles, and soil neutral phosphatase could be the preferred soil enzyme indicator.

  8. Depositional environment, foraminifer content and ESR ages of Quaternary Gediz Delta Sediments (Eastern Aegean Sea, İzmir-Western Turkey)

    NASA Astrophysics Data System (ADS)

    Gökçe Benli, Ekin; Aydın, Hülya; İşintek, İsmail; Engin, Birol; Şengöçmen, Berna

    2016-04-01

    Sediments and fossil content of Gediz Delta (Eastern Aegean Sea - İzmir) were examined based on the drilling core samples of the YSK-C and SK-246 drilling. W-SW part of the Delta is represented by continental delta sediments up to 6 meters and shallow marine detritic sediments up to 35 meters in the YSK-C drilling. Continental part consists of an soiled, graveled, muddy and sandy sediment in terms of rich organic substance. As for marine part, it consists of bioclast, muddy, fine graveled sand and by repetition of pebble, sand and bioclast bearing mud layers. Bioclasts comprise of bivalvia, echinoid, ostracod, gastropod, foramifer and bryozoa fragments. Benthic foraminiferal fauna determinated in the marine levels are represented by 55 bethic, 2 planktonic species. These foraminifers and bioclasts reflect that the W-SW part of the delta, has been occured in marine conditions between 8-31m deep. E-NE part of the delta is generally represented by continental sediments up to 43.5m in SK-246 drilling. In addition, it includes marine levels in 18-19 m, 23-24 m and 36-37,5 m intervals. Continental sediments of E-NE part is generally represented by calcareous and sandy mud rocks which mostly includes ash, tuff, and pebble derived from Neogene volcanic rocks. As for marine levels, it is composed of calcareous mud stones and calcareous clay stones including very thin gastropod, bivalvia and ostracod in 18- 19 and 36-37.5 meters whereas it is represented by sandy mud stones including a great deal of bentic foraminifer, bivalvia, bryozoa, echinoid, gastropod in 23-24 metres. Thus show that E-NE part of the delta is usually in continental condition but it is occasionally covered by sea. In aging studies of YSK-C core done by ESR method, age of 8-9 m interval is determined to be 11. 376 ± 0,067 Ka; however ages of 10-11m and 24-25 m intervals are revealed to be 16.466 ± 0,016 Ka and 15.344 ± 0,021 Ka respectively; finally age of 25-26 m interval is found to be 19.995 ± 0

  9. "Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe

    2016-04-01

    The examination of surface sediment samples collected from 17 sites along the Lomonosov Ridge at water depths ranging from 737 to 3339 meters during Polarstern Expedition PS87 in 2014 (Stein, 2015), indicates a rich biogenic content almost exclusively dominated by calcareous remains. Amongst biogenic remains, microfossils (planktic and benthic foraminifers, pteropods, ostracods, etc.) dominate but millimetric to centrimetric macrofossils occurred frequently at the surface of the sediment. The macrofossil remains consist of a large variety of taxa, including gastropods, bivalvia, polychaete tubes, scaphopods, echinoderm plates and spines, and fish otoliths. Among the Bivalvia, the most abundant taxa are Portlandia arctica, Hyalopecten frigidus, Cuspidaria glacilis, Policordia densicostata, Bathyarca spp., and Yoldiella spp. Whereas a few specimens are well preserved and apparently pristine, most mollusk shells displayed extensive alteration features. Moreover, most shells were covered by millimeter scale tubes of the serpulid polychaete Spirorbis sp. suggesting transport from low intertidal or subtidal zone. Both the ecological affinity and known geographic distribution of identified bivalvia as named above support the hypothesis of transportation rather than local development. In addition to mollusk shells, more than a hundred fish otoliths were recovered in surface sediments. The otoliths mostly belong to the Gadidae family. Most of them are well preserved and without serpulid tubes attached to their surface, suggesting a local/regional origin, unlike the shell remains. Although recovered at the surface, the macrofaunal assemblages of the Lomonosov Ridge do not necessarily represent the "modern" environments as they may result from reworking and because their occurrence at the surface of the sediment may also be due to winnowing of finer particles. Although the shells were not dated, we suspect that their actual ages may range from modern to several thousands of

  10. [Phylogenetic characterization of endosymbionts of the hydrothermal vent mussel Bathymodiolus azoricus by analysis of the 16S rRNA, pmoL, and cbbA genes].

    PubMed

    Spiridonova, E M; Kuznetsov, B B; Pimenov, N V; Turova, T P

    2006-01-01

    In order to assess the phylogenetic diversity of the endosymbiotic microbial community of the gills of marine shellfish Bathymodiolus azoricus, total DNA was extracted from the gills. The PCR fragments corresponding to the genes encoding 16S rRNA, ribulose-bisphosphate carboxylase (cbbL), and particulate methane monooxygenase (pmoA) were amplified, cloned, and sequenced. For the 16S rDNA genes, only one phylotype was revealed; it belonged to the cluster of Mytilidae thiotrophic symbionts within the Gammaproteobacteria. For the RuBisCO genes, two phylotypes were found, both belonging to Gammaproteobacteria. One of them was closely related to the previously known mytilid symbiont, the other, to a pogonophore symbiont, presumably a methanotrophic bacterium. One phylotype of particulate methane oxygenase genes was also revealed; this finding indicated the presence of a methanotrophic symbiont. Phylogenetic analysis of the pmoA placed this endosymbiont within the Gammaproteobacteria, in a cluster including the methanotrophic bacterial genus Methylobacter and other methanotrophic Bathymodiolus gill symbionts. These results provide evidence for the existence of two types of endosymbionts (thioautotrophic and methanotrophic) in the gills of B. azoricus and demonstrate that, apart from the phylogenetic analysis of 16S rRNA genes, parallel analysis of functional genes is essential.

  11. [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.

  12. ROV study of a giant pockmark on the Gabon continental margin

    NASA Astrophysics Data System (ADS)

    Ondréas, H.; Olu, K.; Fouquet, Y.; Charlou, J. L.; Gay, A.; Dennielou, B.; Donval, J. P.; Fifis, A.; Nadalig, T.; Cochonat, P.; Cauquil, E.; Bourillet, J. F.; Moigne, M. Le; Sibuet, M.

    2005-11-01

    A giant, 800-m wide pockmark, called Regab, was discovered along the Equatorial African margin at 3160-m water depth and was explored by remote operated vehicle (ROV) as part of the Zaiango (1998-2000) and Biozaire (2001-2003) projects carried out conjointly by TOTAL and a number of French research institutes. A microbathymetric map obtained using the ROV sensors shows that the pockmark actually consists of a cluster of smaller pockmarks aligned N70 along a 15-m deep depression. Methane was recorded all over the pockmark, the highest values along the axis of the depression where massive carbonate crusts and dense seep communities were also found. Several faunal species belong to the Vesicomyidae and Mytilidae bivalve families, as well as to Siboglinidae (Vestimentifera) tubeworms. Preliminary analyses confirm their association with symbiotic bacteria, thus documenting their dependence on fluid seeps. The pockmark appears to be related to an infilled channel, visible on the seismic data 300 m below the seafloor, which may act as a reservoir for biogenic fluids supplied to the trap from the surrounding sediments.

  13. Off-axis symbiosis found: Characterization and biogeography of bacterial symbionts of Bathymodiolus mussels from Lost City hydrothermal vents.

    PubMed

    DeChaine, Eric G; Bates, Amanda E; Shank, Timothy M; Cavanaugh, Colleen M

    2006-11-01

    Organisms at hydrothermal vents inhabit discontinuous chemical 'islands' along mid-ocean ridges, a scenario that may promote genetic divergence among populations. The 2003 discovery of mussels at the Lost City Hydrothermal Field provided a means of evaluating factors that govern the biogeography of symbiotic bacteria in the deep sea. The unusual chemical composition of vent fluids, the remote location, and paucity of characteristic vent macrofauna at the site, raised the question of whether microbial symbioses existed at the extraordinary Lost City. If so, how did symbiotic bacteria therein relate to those hosted by invertebrates at the closest known hydrothermal vents along the Mid-Atlantic Ridge (MAR)? To answer these questions, we performed microscopic and molecular analyses on the bacteria found within the gill tissue of Bathymodiolus mussels (Mytilidae, Bathymodiolinae) that were discovered at the Lost City. Here we show that Lost City mussels harbour chemoautotrophic and methanotrophic endosymbionts simultaneously. Furthermore, populations of the chemoautotrophic symbionts from the Lost City and two sites along the MAR are genetically distinct from each other, which suggests spatial isolation of bacteria in the deep sea. These findings provide new insights into the processes that drive diversification of bacteria and evolution of symbioses at hydrothermal vents.

  14. A portable infrared photoplethysmograph: heartbeat of Mytilus galloprovincialis analyzed by MRI and application to Bathymodiolus septemdierum

    PubMed Central

    Seo, Eriko; Sazi, Toshiyuki; Togawa, Morio; Nagata, Osamu; Murakami, Masataka; Kojima, Shigeaki

    2016-01-01

    ABSTRACT Infrared photoplethysmogram (IR-PPG) and magnetic resonance image (MRI) of the Mytilus galloprovincialis heart were obtained simultaneously. Heart rate was varied by changing temperature, aerial exposure and hypoxia. Higher heart rates (35-20 beat min−1) were usually observed at 20°C under the aerobic condition, and typical IR-PPG represented a single peak (peak v). The upward and downward slopes of the peak v corresponded to the filling and contracting of the ventricle, respectively. A double-peak IR-PPG was observed in a wide range of heart rates (5 to 35 beats min−1) under various conditions. The initial peak v corresponded to the filling of the ventricle, and the origin of the second peak (v’) varied with the heart rate. A flat IR-PPG with a noise-level represented cardiac arrest. Although large movement of the shells and the foot caused slow waves or a baseline drift of the IR-PPG, the heart rate can be calculated from the v-v interval. Based on these results, we assembled a portable IR-PPG recording system, and measured the heartbeats of Bathymodiolus septemdierum (Mytilidae) for 24 h on a research vessel just after sampling from the deep sea, showing that IR-PPG is a noninvasive, economical, robust method that can be used in field experiments. PMID:27760729

  15. Chemosynthetic bacteria found in bivalve species from mud volcanoes of the Gulf of Cadiz.

    PubMed

    Rodrigues, Clara F; Webster, Gordon; Cunha, Marina R; Duperron, Sébastien; Weightman, Andrew J

    2010-09-01

    As in other cold seeps, the dominant bivalves in mud volcanoes (MV) from the Gulf of Cadiz are macrofauna belonging to the families Solemyidae (Acharax sp., Petrasma sp.), Lucinidae (Lucinoma sp.), Thyasiridae (Thyasira vulcolutre) and Mytilidae (Bathymodiolus mauritanicus). The delta(13)C values measured in solemyid, lucinid and thyasirid specimens support the hypothesis of thiotrophic nutrition, whereas isotopic signatures of B. mauritanicus suggest methanotrophic nutrition. The indication by stable isotope analysis that chemosynthetic bacteria make a substantial contribution to the nutrition of the bivalves led us to investigate their associated bacteria and their phylogenetic relationships based on comparative 16S rRNA gene sequence analysis. PCR-denaturing gradient gel electrophoresis analysis and cloning of bacterial 16S rRNA-encoding genes confirmed the presence of sulfide-oxidizing symbionts within gill tissues of many of the studied specimens. Phylogenetic analysis of bacterial 16S rRNA gene sequences demonstrated that most bacteria were related to known sulfide-oxidizing endosymbionts found in other deep-sea chemosynthetic environments, with the co-occurrence of methane-oxidizing symbionts in Bathymodiolus specimens. This study confirms the presence of several chemosynthetic bivalves in the Gulf of Cadiz and further highlights the importance of sulfide- and methane-oxidizing symbionts in the trophic ecology of macrobenthic communities in MV.

  16. Segregation of sperm mitochondria in two- and four-cell embryos of the blue mussel Mytilus edulis: Implications for the mechanism of doubly uniparental inheritance of mitochondrial DNA.

    PubMed

    Cogswell, Andrew T; Kenchington, Ellen L R; Zouros, Eleftherios

    2006-07-01

    Species of the family Mytilidae have 2 mitochondrial genomes, one that is transmitted through the egg and one that is transmitted through the sperm. In the Mytilus edulis species complex (M. edulis, M. galloprovincialis, and M. trossulus) there is also a strong mother-dependent sex-ratio bias in favor of one or the other sex among progeny from pair matings. In a previous study, we have shown that sperm mitochondria enter the egg and that their behavior during cell division is different depending on whether the egg originated from a female- or male-biased mother. Specifically, in eggs from females that produce mostly or exclusively daughters, sperm mitochondria disperse randomly among cells after egg division. In eggs from females that produce predominantly sons, sperm mitochondria tend to stay together in the same cell. Here, we extend these observations and show that in 2- and 4-cell embryos from male-biased mothers most sperm mitochondria are located near or at the cleavage furrow of the major cell, in contrast to embryos from female-biased mothers where there is no preferential association of sperm mitochondria with the cleavage furrow. This observation provides evidence for an early developmental mechanism through which sperm mitochondria are preferentially channeled into the primordial cells of male embryos, thus making the paternal mitochondrial genome the dominant mtDNA component of the male germ line.

  17. Aspects of Biodeterioration of Lapideous Submerged Artefacts: 3d Methodologies Application

    NASA Astrophysics Data System (ADS)

    Ricci, S.; Antonelli, F.; Sacco Perasso, C.

    2015-04-01

    Submerged stone archaeological artefacts are bioeroded by endolithic microbiota (cyanobacteria, algae and fungi) and macroborers (Porifera, Bivalvia and Sipuncula). Optical microscope and SEM observations permit to analyse the bioerosion traces and to identify bioeroders. Data obtained with these techniques cannot be used to estimate volumes of material bioeroded. This aspect require the need to collect three-dimensional, close-range data from artefact. In this work we illustrate two 3D imaging techniques used to study bioerosion phenomena of underwater Cultural Heritage. In particular Digital Video Microscope permit the elaboration of 3D images, which are widely employed for close-range acquisitions. Underwater Laser Scanner documents the in situ degradation of submerged artefacts. This research aims to sensitize specialist figures in the study 3D offering a starting point for future collaborations that could lead to interesting results.

  18. Investigation of molluscan phylogeny on the basis of 18S rRNA sequences.

    PubMed

    Winnepenninckx, B; Backeljau, T; De Wachter, R

    1996-12-01

    The 18S rRNA sequences of 12 molluscs, representing the extant classes Gastropoda, Bivalvia, Polyplacophora, Scaphopoda, and Caudofoveata, were determined and compared with selected known 18S rRNA sequences of Metazoa, including other Mollusca. These data do not provide support for a close relationship between Platyhelminthes (Turbellaria) and Mollusca, but rather suggest that the latter group belongs to a clade of eutrochozoan coelomates. The 18S rRNA data fail to recover molluscan, bivalve, or gastropod monophyly. However, the branching pattern of the eutrochozoan phyla and classes is unstable, probably due to the explosive Cambrian radiation during which these groups arose. Similarly, the 18S rRNA data do not provide a reliable signal for the molluscan interclass relationships. Nevertheless, we obtained strong preliminary support for phylogenetic inferences at more restricted taxonomic levels, such as the monophyly of Polyplacophora, Caenogastropoda, Euthyneura, Heterodonta, and Arcoida.

  19. Foods of Spectacled Eiders Somateria fischeri in the Bering Sea, Alaska

    USGS Publications Warehouse

    Petersen, M.R.; Piatt, J.F.; Trust, K.A.

    1998-01-01

    The winter diet of Spectacled Eiders living in marine habitats is known only from two individuals described by Cottam (1939). Here we examine marine diets from 36 stomachs collected near St. Lawrence Island, Bering Sea, Alaska, during May-June in 1987 and 1992. All Spectacled Eiders ate Mollusca, including Gastropoda (snails; frequency of occurrence 20.0%; sole taxon 0.0%) and Bivalvia (bivalves; 80.0%; 48.0%), and Crustacea (barnacles, amphipods and crabs; 30.6%; 0.0%). One bird ate a cod. The predominant species group eaten was Macoma Clams (72.0%; 36.0%). Prey species of Spectacled Eiders occur predominantly in waters 25-60 m deep in the Bering Sea. To obtain these prey, especially the bivalves, on the winter area Spectacled Eiders must forage in waters exceeding 40 m. We speculate that Spectacled Eiders regularly forage at depths of 45-70 m throughout winter.

  20. Hemocyanin respiratory pigment in bivalve mollusks

    SciTech Connect

    Morse, M.P.; Meyhoefer, E.; Otto, J.J.; Kuzirian, A.M.

    1986-03-14

    Hemocyanins, high molecular weight oxygen-binding proteins, were identified in two species of protobranch bivalve mollusks, Acila castrensis and Yoldia limatula. Although hemocyanins have been reported in chitons, gastropods, and cephalopods, they have not been observed in the Class Bivalvia. In A. castrensis the dissociation products of hemocyanin, characterized by gel electrophoresis, had a subunit molecular weight of approximately 250K. Negatively stained preparations of extracted hemocyanin formed protein aggregates in the shape of cylinders measuring 35 by 38 nanometers. X-ray microanalysis of hemocyanin aggregates in thin sections of Y. limatula demonstrated the presence of copper in the molecules. The discovery of hemocyanin in the protobranchs reinforces the primitive nature of the taxon and is further evidence that the major molluscan classes have a common ancestry. 14 references, 3 figures.

  1. Aragonite shells are more ancient than calcite ones in bivalves: new evidence based on omics.

    PubMed

    Wang, Xiaotong; Li, Li; Zhu, Yabing; Song, Xiaorui; Fang, Xiaodong; Huang, Ronglian; Que, Huayong; Zhang, Guofan

    2014-11-01

    Two calcium carbonate crystal polymorphs, aragonite and calcite, are the main inorganic components of mollusk shells. Some fossil evidences suggest that aragonite shell is more ancient than calcite shell for the Bivalvia. But, the molecular biology evidence for the above deduction is absent. In this study, we searched for homologs of bivalve aragonite-related and calcite-related shell proteins in the oyster genome, and found that no homologs of calcite-related shell protein but some homologs of aragonite-related shell proteins in the oyster genome. We explained the results as the new evidence to support that aragonite shells are more ancient than calcite shells in bivalves combined the published biogeological and seawater chemistry data.

  2. Crystallization in organo-mineral micro-domains in the crossed-lamellar layer of Nerita undata (Gastropoda, Neritopsina).

    PubMed

    Nouet, Julius; Baronnet, Alain; Howard, Lauren

    2012-02-01

    Crossed-lamellar shell microstructure consists of a sophisticated arrangement of interspersed lamellae, which is very commonly found in Gastropoda or Bivalvia shell layers. Its smallest constitutive microstructural units are usually described as sub-micrometric fibers, or rods, and form very ordered and regular patterns. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) imaging confirms the presence of even smaller building units in the form of organo-mineral granules, and we further investigate their internal structure within aragonite crossed-lamellar internal layer of Nerita undata (Gastropoda, Neritopsina) shell. Their coalescence may have controlled anisotropically the propagation of the crystallographic coherence through this complex microstructure, as suggested by the propagation of the microtwinning pattern between neighboring granules.

  3. Life-cycle and biology of Sychnocotyle kholo n.g., n. sp. (Trematoda : Aspidogastrea) in Emydura macquarii (Pleurodira : Chelidae) from southern Queensland, Australia.

    PubMed

    Ferguson, M A; Cribb, T H; Smales, L R

    1999-05-01

    Sychnocotyle kholo n. g., n. sp. (Aspidogastrea: Aspidogastridae) is described from the small intestine of the freshwater turtle Emydura macquarii (Pleurodira: Chelidae). The new genus is distinguished from other aspidogastrids by the possession of the following suite of characters: no cirrus-sac; no hermaphroditic duct; four rows of alveoli on the ventral disc but no prominent papillae; Laurer's canal opening to the exterior. Eggs hatched to cotylocidia within 37-41 days at 17-24 degrees C. The life-cycle is obligate two-host, involving a mollusc and a freshwater turtle. Juvenile forms, almost entirely single worm infections, were found in the molluscs Corbiculina sp. (Bivalvia: Corbiculidae) and Thiara balonnensis (Prosobranchia: Thiaridae). Sychnocotyle is most likely to have evolved in Australia after the separation of Gondwanaland from Laurasia 120- 100 mya.

  4. An Efficient Method for Genomic DNA Extraction from Different Molluscs Species

    PubMed Central

    Pereira, Jorge C.; Chaves, Raquel; Bastos, Estela; Leitão, Alexandra; Guedes-Pinto, Henrique

    2011-01-01

    The selection of a DNA extraction method is a critical step when subsequent analysis depends on the DNA quality and quantity. Unlike mammals, for which several capable DNA extraction methods have been developed, for molluscs the availability of optimized genomic DNA extraction protocols is clearly insufficient. Several aspects such as animal physiology, the type (e.g., adductor muscle or gills) or quantity of tissue, can explain the lack of efficiency (quality and yield) in molluscs genomic DNA extraction procedure. In an attempt to overcome these aspects, this work describes an efficient method for molluscs genomic DNA extraction that was tested in several species from different orders: Veneridae, Ostreidae, Anomiidae, Cardiidae (Bivalvia) and Muricidae (Gastropoda), with different weight sample tissues. The isolated DNA was of high molecular weight with high yield and purity, even with reduced quantities of tissue. Moreover, the genomic DNA isolated, demonstrated to be suitable for several downstream molecular techniques, such as PCR sequencing among others. PMID:22174651

  5. Sperm motility in Mytilus edulis in relation to mitochondrial DNA polymorphisms: implications for the evolution of doubly uniparental inheritance in bivalves.

    PubMed

    Jha, M; Côté, J; Hoeh, W R; Blier, P U; Stewart, D T

    2008-01-01

    Bivalves of the families Mytilidae, Unionidae, and Veneridae have an unusual mode of mitochondrial DNA (mtDNA) transmission called doubly uniparental inheritance (DUI). A characteristic feature of DUI is the presence of two gender-associated mtDNA genomes that are transmitted through males (M-type mtDNA) and females (F-type mtDNA), respectively. Female mussels are predominantly homoplasmic with only the F-type expressed in both somatic and gonadal tissue; males are heteroplasmic with the M-type expressed in the gonad and F-type in somatic tissue for the most part. An unusual evolutionary feature of this system is that an mt genome with F-coding sequences occasionally invades the male route of inheritance (i.e., a "role reversal" event), and is thereafter transmitted as a new M-type. Phylogenetic studies have demonstrated that the new or "recently masculinized" M-types may eventually replace the older or "standard" M-types over time. To investigate whether this replacement process could be due to an advantage in sperm swimming behavior, we measured differences in motility parameters and found that sperm with the recently masculinized M-type had significantly faster curvilinear velocity and average path velocity when compared to sperm with standard M-type. This increase in sperm swimming speed could explain the multiple evolutionary replacements of standard M-types by masculinized M-types that have been hypothesized for the mytilid lineage. However, our observations do not support the hypothesis that DUI originated because it permits the evolution of mitochondrial adaptations specific to sperm performance, otherwise, the evolutionarily older, standard M genome should perform better.

  6. Cold seep communities in the deep eastern Mediterranean Sea: composition, symbiosis and spatial distribution on mud volcanoes

    NASA Astrophysics Data System (ADS)

    Olu-Le Roy, Karine; Sibuet, Myriam; Fiala-Médioni, Aline; Gofas, Serge; Salas, Carmen; Mariotti, André; Foucher, Jean-Paul; Woodside, John

    2004-12-01

    Two mud volcano fields were explored during the French-Dutch MEDINAUT cruise (1998) with the submersible NAUTILE, one south of Crete along the Mediteranean Ridge at about 2000 m depth (Olimpi mud field) and the other south of Turkey between 1700 and 2000 m depth (Anaximander mud field) where high methane concentrations were measured. Chemosynthetic communities were observed and sampled on six mud volcanoes and along a fault scarp. The communities were dominated by bivalves of particularly small size, belonging to families commonly found at seeps (Mytilidae, Vesicomyidae, Thyasiridae) and to Lucinidae mostly encountered in littoral sulfide-rich sediments and at the shallowest seeps. Siboglinid polychaetes including a large vestimentiferan Lamellibrachia sp. were also associated. At least four bivalve species and one siboglinid are associated with symbiotic chemoautotrophic bacteria, as evidenced by Transmission Electronic Microscopy and isotopic ratio measurements. Among the bivalves, a mytilid harbors both methanotrophic and sulfide-oxidizing bacteria. Video spatial analysis of the community distribution on three volcanoes shows that dense bivalve shell accumulations (mainly lucinids) spread over large areas, from 10% to 38% of the explored areas (2500-15000 m 2) on the different volcanoes. Lamellibrachia sp. had different spatial distribution and variable density in the two mud volcano fields, apparently related with higher methane fluxes in the Anaximander volcanoes and maybe with the instability due to brines in the Olimpi area. The abundance and richness of the observed chemosynthetic fauna and the size of some of the species contrast with the poverty of the deep eastern Mediterranean. The presence of a specialized fauna, with some mollusk genera and species shared with other reduced environments of the Mediterranean, but not dominated by the large bivalves usually found at seeps, is discussed.

  7. Changes in benthos associated with mussel (Mytilus edulis L.) farms on the west-coast of Scotland.

    PubMed

    Wilding, Thomas A; Nickell, Thomas D

    2013-01-01

    Aquaculture, as a means of food production, is growing rapidly in response to an increasing demand for protein and the over-exploitation of wild fisheries. This expansion includes mussels (family Mytilidae) where production currently stands at 1.5 million tonnes per annum. Mussel culture is frequently perceived as having little environmental impact yet mussel biodeposits and shell debris accumulate around the production site and are linked to changes in the benthos. To assess the extent and nature of changes in benthos associated with mussel farming grab and video sampling around seven mussel farms was conducted. Grab samples were analysed for macrofauna and shell-hash content whilst starfish were counted and the shell-hash cover estimated from video imaging. Shell-hash was patchily distributed and occasionally dominated sediments (maximum of 2116 g per 0.1 m(2) grab). Mean shell-hash content decreased rapidly at distances >5 m from the line and, over the distance 1-64 m, decreased by three orders of magnitude. The presence of shell-hash and the distance-from-line influenced macrofaunal assemblages but this effect differed between sites. There was no evidence that mussel farming was associated with changes in macrobenthic diversity, species count or feeding strategy. However, total macrofaunal count was estimated to be 2.5 times higher in close proximity to the lines, compared with 64 m distance, and there was evidence that this effect was conditional on the presence of shell-hash. Starfish density varied considerably between sites but, overall, they were approximately 10 times as abundant close to the mussel-lines compared with 64 m distance. There was no evidence that starfish were more abundant in the presence of shell-hash visible on the sediment surface. In terms of farm-scale benthic impacts these data suggest that mussel farming is a relatively benign way of producing food, compared with intensive fish-farming, in similar environments.

  8. Maternal inheritance of mitochondrial DNA (mtDNA) in the Pacific oyster (Crassostrea gigas): a preliminary study using mtDNA sequence analysis with evidence of random distribution of MitoTracker-stained sperm mitochondria in fertilized eggs.

    PubMed

    Obata, Mayu; Shimizu, Michiyo; Sano, Natsumi; Komaru, Akira

    2008-03-01

    In many bivalve species, paternal and maternal mitochondrial DNA (mtDNA) from sperm and eggs is transmitted to the offspring. This phenomenon is known as doubly uniparental inheritance (DUI). In these species, sperm mtDNA (M type) is inherited by the male gonad of the offspring. Egg mtDNA (F type) is inherited by both male and female somatic cells and female gonadal cells. In Mytilidae, sperm mitochondria are distributed in the cytoplasm of differentiating male germ cells because they are transmitted to the male gonad. In the present study, we investigated maternal inheritance of mtDNA in the Pacific oyster, Crassostrea gigas. Sequence analysis of two mitochondrial non-coding regions revealed an identical sequence pattern in the gametes and adductor muscle samples taken from six males and five females. To observe whether sperm mitochondria were specifically located in the cytoplasm of differentiating germ cells, their distribution was recorded in C. gigas fertilized eggs by vital staining with MitoTracker Green. Although the 1D blastomere was identified in the cytoplasm of differentiating germ cells, sperm mitochondria were located at the 1D blastomere in only 32% of eggs during the 8-cell stage. Thus, in C. gigas, sperm mitochondria do not specifically locate in the germ cell region at the 1D blastomere. We suggest that the distribution of sperm mitochondria is not associated with germ cell formation in C. gigas. Furthermore, as evidenced by the mtDNA sequences of two non-coding regions, we conclude that mitochondrial DNA is maternally inherited in this species.

  9. Changes in Benthos Associated with Mussel (Mytilus edulis L.) Farms on the West-Coast of Scotland

    PubMed Central

    Wilding, Thomas A.; Nickell, Thomas D.

    2013-01-01

    Aquaculture, as a means of food production, is growing rapidly in response to an increasing demand for protein and the over-exploitation of wild fisheries. This expansion includes mussels (family Mytilidae) where production currently stands at 1.5 million tonnes per annum. Mussel culture is frequently perceived as having little environmental impact yet mussel biodeposits and shell debris accumulate around the production site and are linked to changes in the benthos. To assess the extent and nature of changes in benthos associated with mussel farming grab and video sampling around seven mussel farms was conducted. Grab samples were analysed for macrofauna and shell-hash content whilst starfish were counted and the shell-hash cover estimated from video imaging. Shell-hash was patchily distributed and occasionally dominated sediments (maximum of 2116 g per 0.1 m2 grab). Mean shell-hash content decreased rapidly at distances >5 m from the line and, over the distance 1–64 m, decreased by three orders of magnitude. The presence of shell-hash and the distance-from-line influenced macrofaunal assemblages but this effect differed between sites. There was no evidence that mussel farming was associated with changes in macrobenthic diversity, species count or feeding strategy. However, total macrofaunal count was estimated to be 2.5 times higher in close proximity to the lines, compared with 64 m distance, and there was evidence that this effect was conditional on the presence of shell-hash. Starfish density varied considerably between sites but, overall, they were approximately 10 times as abundant close to the mussel-lines compared with 64 m distance. There was no evidence that starfish were more abundant in the presence of shell-hash visible on the sediment surface. In terms of farm-scale benthic impacts these data suggest that mussel farming is a relatively benign way of producing food, compared with intensive fish-farming, in similar environments. PMID:23874583

  10. Continental shelf benthos off Otago Peninsula, New Zealand

    NASA Astrophysics Data System (ADS)

    Probert, P. Keith; Wilson, John B.

    1984-09-01

    Benthic macrofauna of the continental shelf off Otago Peninsula, south-eastern New Zealand (45°51'S, 170°52'E) was surveyed by dredge sampling during 1973-1975. Numerical classification (Canberra metric coefficient and flexible sorting) was used to produce site groups and species groups, and three major benthic communities were recognised: a shallow-water (14-25 m) fauna inhabiting well-sorted fine sand, a mid-shelf fauna (concentrated in the depth range 50-76 m) associated with sediments containing the greatest proportions of gravel and siltclay, and a predominantly sand-bottom fauna occurring mainly on the outer shelf (87-150 m). All station groups were dominated numerically by polychaetes (mean of 36·6-56% of individuals) with Mollusca (13·8-25%) or Crustacea (12·1-19·4%) the next most abundant group. The inshore sand fauna was the most distinct, characteristic elements being the trochid gastropod Antisolarium egenum, an amphipod of the genus Hippomedon and dense patches of the spionid polychaete Spiophanes bombyx. Diagnostic species of the mid-shelf mixed sediments were Lepidonotus jacksoni, Psammolyce antipoda, Lumbrineris brevicirra and Phyllamphicteis foliata (Polychaeta), Terenochiton otagoensis, Micrelenchus caelatus caelatus, Maoricolpus roseus roseus and Zegalerus tenuis (Mollusca), Ampelisca chiltoni (Amphipoda) and Amphipholis squamata (Ophiuroidea). Outer shelf sand stations were faunally less distinct, but among the more characteristic species were Euthalenessa fimbriata, Sigalion sp. and Euchone sp. (Polychaeta) and Gari stangeri (Bivalvia). Several abundant species were widely distributed among station groups, notably Nephtys macroura, Lumbrineris magalhaensis, Phyllochaetopterus socialis and Owenia fusiformis (Polychaeta) and Nucula nitidula and Tawera spissa (Bivalvia). Free-living lunulitiform Bryozoa of the genus Otionella were a characteristic component of inner and outer shelf sand faunas, and their inshore penetration probably marks

  11. Screening of plant extracts for anthelmintic activity against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus).

    PubMed

    Huang, Ai-Guo; Yi, Yang-Lei; Ling, Fei; Lu, Lin; Zhang, Qi-Zhong; Wang, Gao-Xue

    2013-12-01

    With the aim of finding natural anthelmintic agents against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus), 26 plants were screened for antiparasitic properties using in vivo anthelmintic efficacy assay. The results showed that Caesalpinia sappan, Lysima chiachristinae, Cuscuta chinensis, Artemisia argyi, and Eupatorium fortunei were found to have 100% anthelmintic efficacy at 125, 150, 225, 300, and 500 mg L(-1) after 48 h of exposure. Crude extract of the five plants were further partitioned with petroleum ether, chloroform, ethyl acetate, methanol, and water to obtain anthelmintically active fractions with various polarity. Among these fractions tested, the ethyl acetate extract of L. chiachristinae was found to be the most effective with a 50% effective concentration (EC50) value of 5.1 mg/L after 48 h of exposure. This was followed by ethyl acetate extract of C. chinensis (48 h-EC50 = 8.5 mg L(-1)), chloroform extracts of C. sappan (48 h-EC50 = 15.6 mg L(-1)), methanol extract of C. chinensis (48 h-EC50 = 15.9 mg L(-1)), and chloroform and petroleum ether extract of L. chiachristinae (EC50 values of 17.2 and 21.1 mg/L, respectively), suggesting that these plants, as well as the active fractions, provide potential sources of botanic drugs for the control of D. intermedius in aquaculture.

  12. Mixed forest plantations can efficiently filter rainfall deposits of sulfur and chlorine in Western China

    NASA Astrophysics Data System (ADS)

    Zhao, Hairong; Yang, Wanqin; Wu, Fuzhong; Tan, Bo

    2017-01-01

    Forest filtering is a well-known and efficient method for diminishing atmospheric pollutant (such as SO42‑ and Cl‑) inputs to soil and water; however, the filtering efficiencies of forests vary depending on the regional vegetation and climate. The rainy area of West China has suffered from heavy rainfall and human activity, which has potentially resulted in large amounts of sulfur and chlorine deposition, but little information is available regarding the filtering effects of typical plantations. Therefore, the migration of SO42‑ and Cl‑ from rainfall to throughfall, stemflow and runoff were investigated in a camphor (Cinnamomum camphora) plantation, a cryptomeria (Cryptomeria fortunei) plantation and a mixed plantation in a 9-month forest hydrology experiment. The results indicated the following: (i) The total SO42‑ and Cl‑ deposition was 43.05 kg ha‑1 and 5.25 kg ha‑1, respectively. (ii) The cover layer had the highest interception rate (60.08%), followed by the soil layer (16.02%) and canopy layer (12.85%). (iii) The mixed plantation resulted in the highest SO42‑ (37.23%) and Cl‑ (51.91%) interception rates at the forest ecosystem scale, and the interception rate increased with increasing rainfall. These results indicate that mixed plantations can effectively filter SO42‑ and Cl‑ in this area and in similar areas.

  13. Quantitative genetic analysis of subspecific differences in body shape in the snail-feeding carabid beetle Damaster blaptoides.

    PubMed

    Konuma, J; Sota, T; Chiba, S

    2013-01-01

    A dimorphic pattern of macrocephalic (wide, short) and stenocephalic (narrow, long) body shapes is observed in snail-feeding carabid beetles globally. The former exhibits high performance in crushing snail shells with powerful jaws, whereas the latter specializes in eating snails' soft body directly by inserting the head into the shell. In the snail-feeding species Damaster blaptoides, the subspecies D. b. capito has a wide, short forebody, and D. b. fortunei has a narrow, long forebody. They exhibit distinct morphologies despite their geographic and phylogenetic proximity. To examine the genetic basis of the morphological differences between these two subspecies, we conducted quantitative genetic analyses by crossing these subspecies and producing F(1) and backcross hybrids. The hybrids had body shapes intermediate between the parental subspecies. The variation between wide, short and narrow, long forebodies was based on negative genetic correlations between width and length of the head and thorax. Between one and eight genetic factors were involved in the morphological differences between subspecies. We suggest that the morphological integration of forebody parts in a small number of loci has facilitated the marked morphological diversification between subspecies of D. blaptoides.

  14. A Spatial Modeling Approach to Predicting the Secondary Spread of Invasive Species Due to Ballast Water Discharge

    PubMed Central

    Sieracki, Jennifer L.; Bossenbroek, Jonathan M.; Chadderton, W. Lindsay

    2014-01-01

    Ballast water in ships is an important contributor to the secondary spread of invasive species in the Laurentian Great Lakes. Here, we use a model previously created to determine the role ballast water management has played in the secondary spread of viral hemorrhagic septicemia virus (VHSV) to identify the future spread of one current and two potential invasive species in the Great Lakes, the Eurasian Ruffe (Gymnocephalus cernuus), killer shrimp (Dikerogammarus villosus), and golden mussel (Limnoperna fortunei), respectively. Model predictions for Eurasian Ruffe have been used to direct surveillance efforts within the Great Lakes and DNA evidence of ruffe presence was recently reported from one of three high risk port localities identified by our model. Predictions made for killer shrimp and golden mussel suggest that these two species have the potential to become rapidly widespread if introduced to the Great Lakes, reinforcing the need for proactive ballast water management. The model used here is flexible enough to be applied to any species capable of being spread by ballast water in marine or freshwater ecosystems. PMID:25470822

  15. [Morphological and histological studies on the Chinese drug shan-dou-gen].

    PubMed

    Fang, L Q; Guo, J X

    1992-01-01

    The Chinese drug "Shan-Dou-Gen" has been used for removing toxic heat, promoting the subsidence of swelling and soothing the sore throat since the ancient time. The authors made a survey of the drug "Shan-Dou-Gen" available in drug markets as well as the plant origin from the drug producing districts. The results showed that the drug "Shan-Dou-Gen" used in different regions in China at present are the roots or rhizomes derived from 9 species: Sophora tonkinensis Gagnep. (Leguminosae), Menispermum dauricum DC. (Menispermaceae), Indigofera amblyantha Craib (Leguminosae), I. carlesii Carib, I., fortunei Craib, I. decoa Lindl. var. ichangensis Y. Y. Fang et C. Z. Zheng, I. kirilowii Maxim. et Palibin, I. potaninii Craib, and Beesia calthaefolia (Maxim.) Ulbr. (Ranuculaceae). In this paper, the morphological characters of the crude drugs are described, compared and illustrated with photographs. The histological structures of the used parts are described, compared and illustrated with line drawings. The morphological and histological similarities and differences found among the above 9 species are summarized, and the key for the identification of the crude drugs is provided. As the drug "Shan-Dou-Gen" derived from different species has different actions and dosages, it is necessary to give different names to different species and use them correctly.

  16. Mixed forest plantations can efficiently filter rainfall deposits of sulfur and chlorine in Western China

    PubMed Central

    Zhao, Hairong; Yang, Wanqin; Wu, Fuzhong; Tan, Bo

    2017-01-01

    Forest filtering is a well-known and efficient method for diminishing atmospheric pollutant (such as SO42− and Cl−) inputs to soil and water; however, the filtering efficiencies of forests vary depending on the regional vegetation and climate. The rainy area of West China has suffered from heavy rainfall and human activity, which has potentially resulted in large amounts of sulfur and chlorine deposition, but little information is available regarding the filtering effects of typical plantations. Therefore, the migration of SO42− and Cl− from rainfall to throughfall, stemflow and runoff were investigated in a camphor (Cinnamomum camphora) plantation, a cryptomeria (Cryptomeria fortunei) plantation and a mixed plantation in a 9-month forest hydrology experiment. The results indicated the following: (i) The total SO42− and Cl− deposition was 43.05 kg ha−1 and 5.25 kg ha−1, respectively. (ii) The cover layer had the highest interception rate (60.08%), followed by the soil layer (16.02%) and canopy layer (12.85%). (iii) The mixed plantation resulted in the highest SO42− (37.23%) and Cl− (51.91%) interception rates at the forest ecosystem scale, and the interception rate increased with increasing rainfall. These results indicate that mixed plantations can effectively filter SO42− and Cl− in this area and in similar areas. PMID:28134356

  17. Heterogeneous evolution of Ty3-gypsy retroelements among bamboo species.

    PubMed

    An, M M; Guo, C; Lin, P P; Zhou, M B

    2016-08-19

    Ty3-gypsy long-terminal repeat retroelements are ubiquitously found in many plant genomes. This study reports the occurrence of heterogeneous Ty3-gypsy retroelements in four representative bamboo species: Phyllostachys heterocycla (Carr.) Mitford cv. pubescens, P. heterocycla (Carr.) Mitford cv. heterocycla, Dendrocalamopsis oldhami, and Pleioblastus fortunei. Using degenerate oligonucleotide primers corresponding to the conserved domains of reverse transcriptase (rt) genes of Ty3-gypsy retroelements, 165 distinct sequences were amplified from genomic DNA. The length of the nucleotide sequences varied from 366 to 438 bp. The sequences demonstrated a high heterogeneity, with homology ranging from 52.2 to 99.8%. A phylogenetic tree was constructed, including Arabidopsis thaliana and Oryza sativa. Bamboo Ty3-gypsy sequences formed three distinct retroelement clusters (gypsy I-III). Further analysis indicated that there were not only nearly identical Ty3-gypsy retroelements found in distantly related species, but also highly diverse Ty3-gypsy retroelements observed in closely related species. The results of this study provide genetic and evolutionary information about the bamboo genome that could contribute to further studies of repetitive elements in bamboo as well as in other species.

  18. The suppressive activities of six sources of medicinal ferns known as gusuibu on heat-labile enterotoxin-induced diarrhea.

    PubMed

    Chang, Hung-Chi; Chen, Jaw-Chyun; Yang, Jiun-Long; Tsay, Hsin-Sheng; Hsiang, Chien-Yun; Ho, Tin-Yun

    2014-02-18

    Diarrheal disease is one of the most important worldwide health problems. Enterotoxigenic Escherichia coli (ETEC) is the most frequently isolated enteropathogen in diarrheal diseases. In developing countries, a very large number of people, especially children, suffer from diarrhea. To combat this problem, World Health Organization has constituted the Diarrhea Diseases Control Program which guides studies on traditional medicinal practices and preventive measures. Gusuibu, a traditional folk medicine, has been claimed to heal certain types of diarrhea. However, so far no scientific study has been carried out on the anti-diarrheal mechanism of Gusiubu. The present study was performed to examine the suppressive activities of ethanol extracts of six sources of folk medicinal ferns used as Gusuibu on heat-labile enterotoxin (LT)-induced diarrhea. Inhibitory effects of six sources were evaluated on the ETEC LT subunit B (LTB) and monosialotetrahexosylganglioside (GMI) interaction by GM1-enzyme linked immunosorbent assay and patent mouse gut assay. Our results indicated that Drynaria fortunei had no anti-diarrheal effect, while, among the remaining five folk medicinal ferns, four belonging to family Davalliaceae had significant abilities on both the blocking of LTB and GM1 interaction and the inhibition of LT-induced diarrhea. In conclusion, these findings suggested the potential application of Gusuibu as an anti-diarrheal remedy.

  19. Screening of inhibitors of glycogen synthase kinase-3β from traditional Chinese medicines using enzyme-immobilized magnetic beads combined with high-performance liquid chromatography.

    PubMed

    Li, Yunfang; Xu, Jia; Chen, Yu; Mei, Zhinan; Xiao, Yuxiu

    2015-12-18

    Glycogen synthase kinase-3β (GSK-3β) was immobilized on magnetic beads (MBs) by affinity method for the first time. The enzyme-immobilized MBs were coupled with high-performance liquid chromatography-ultraviolet (HPLC-UV) technique to establish a cost-effective and reliable method for screening of inhibitors of GSK-3β. A peptide substrate of GSK-3β containing a tyrosine residue was employed since it can be sensitively detected by UV detector at 214nm. The substrate and its phosphorylated product were separated by baseline within 10min. The enzyme activity was determined by the quantification of peak area of the product. Parameters including enzyme immobilization, enzyme reaction and the performance of immobilized-enzyme were investigated. The immobilized enzyme can be reused for 10 times and remain stable for 4 days at 4°C. The inhibitory activities of extracts of 15 traditional Chinese medicines (TCMs) were screened. As a result, three of them including Euonymus fortunei, Amygdalus communis and Garcinia xanthochymus were found possessing high inhibitory activities (inhibition rate >90%). From G. xanthochymus, a new inhibitor of GSK-3β, fukugetin, was discovered with an IC50 value of 3.18±0.07μM. Enzyme kinetics and molecular docking experiments further revealed the inhibitory mechanism, indicating fukugetin was a non-ATP competitive inhibitor interacting with the phosphate recognizing substrate binding site of GSK-3β.

  20. A spatial modeling approach to predicting the secondary spread of invasive species due to ballast water discharge.

    PubMed

    Sieracki, Jennifer L; Bossenbroek, Jonathan M; Chadderton, W Lindsay

    2014-01-01

    Ballast water in ships is an important contributor to the secondary spread of invasive species in the Laurentian Great Lakes. Here, we use a model previously created to determine the role ballast water management has played in the secondary spread of viral hemorrhagic septicemia virus (VHSV) to identify the future spread of one current and two potential invasive species in the Great Lakes, the Eurasian Ruffe (Gymnocephalus cernuus), killer shrimp (Dikerogammarus villosus), and golden mussel (Limnoperna fortunei), respectively. Model predictions for Eurasian Ruffe have been used to direct surveillance efforts within the Great Lakes and DNA evidence of ruffe presence was recently reported from one of three high risk port localities identified by our model. Predictions made for killer shrimp and golden mussel suggest that these two species have the potential to become rapidly widespread if introduced to the Great Lakes, reinforcing the need for proactive ballast water management. The model used here is flexible enough to be applied to any species capable of being spread by ballast water in marine or freshwater ecosystems.

  1. In vitro screening of traditionally used medicinal plants in China against Enteroviruses

    PubMed Central

    Guo, Jin-Peng; Pang, Ji; Wang, Xin-Wei; Shen, Zhi-Qiang; Jin, Min; Li, Jun-Wen

    2006-01-01

    AIM: To search for new antiviral agents from traditional Chinese medicine, specifically anti-enterovirosuses agents. METHODS: The aqueous extracts (AE) of more than 100 traditionally used medicinal plants in China were evaluated for their In vitro anti-Coxsackie virus B3 activities with a MTT-based colorimetric assay. RESULTS: The test for AE of 16 plants exhibited anti-Coxsackie virus B3 activities at different magnitudes of potency. They can inhibit three steps (inactivation, adsorption and replication) during the infection. Among the 16 plants, Sargentodoxa cuneata (Oliv.) Rehd. et Wils., Sophora tonkinensis Gapnep., Paeonia veitchii Lynch, Spatholobus suberectus Dunn. and Cyrtomium fortunei J. sm. also have activity against other enterovirus, including Coxsackie virus B5, Polio virus I, Echo virus 9 and Echo virus 29. Cell cytotoxic assay demonstrated that all tested AE had CC50 values higher than their EC50 values. CONCLUSION: The sixteen traditionally used medicinal plants in China possessed antiviral activity, and some of them merit further investigations. PMID:16810764

  2. Site-Specific N-Glycosylation Characterization of Windmill Palm Tree Peroxidase Using Novel Tools for Analysis of Plant Glycopeptide Mass Spectrometry Data.

    PubMed

    Baker, Margaret R; Tabb, David L; Ching, Travers; Zimmerman, Lisa J; Sakharov, Ivan Y; Li, Qing X

    2016-06-03

    Plant secretory (Class III) peroxidases are redox enzymes that rely on N-glycosylation for full enzyme activity and stability. Peroxidases from palm tree leaves comprise the most stable and active plant peroxidases characterized to date. Herein, site-specific glycosylation and microheterogeneity of windmill palm tree (Trachycarpus fortunei) peroxidase are reported. The workflow developed in this study includes novel tools, written in R, to aid plant glycan identification, pGlycoFilter, for annotation of glycopeptide fragmentation spectra, gPSMvalidator, and for relative quantitation of glycoforms, glycoRQ. Mass spectrometry analysis provided a detailed glycosylation profile at the 13 sites of N-linked glycosylation on windmill palm tree peroxidase. Glycan microheterogeneity was observed at each site. Site Asn211 was the most heterogeneous and contained 30 different glycans. Relative quantitation revealed 90% of each glycosylation site was occupied by three or fewer glycans, and two of the 13 sites were partially unoccupied. Although complex and hybrid glycans were identified, the majority of glycans were paucimannosidic, characteristic of plant vacuolar glycoproteins. Further studies pertaining to the glycan structure-activity relationships in plant peroxidases can benefit from the work outlined here.

  3. Molecular Cloning and Characterization of Full-Length cDNA of Calmodulin Gene from Pacific Oyster Crassostrea gigas

    PubMed Central

    Li, Xing-Xia; Yu, Wen-Chao; Cai, Zhong-Qiang; He, Cheng; Wei, Na

    2016-01-01

    The shell of the pearl oyster (Pinctada fucata) mainly comprises aragonite whereas that of the Pacific oyster (Crassostrea gigas) is mainly calcite, thereby suggesting the different mechanisms of shell formation between above two mollusks. Calmodulin (CaM) is an important gene for regulating the uptake, transport, and secretion of calcium during the process of shell formation in pearl oyster. It is interesting to characterize the CaM in oysters, which could facilitate the understanding of the different shell formation mechanisms among mollusks. We cloned the full-length cDNA of Pacific oyster CaM (cgCaM) and found that the cgCaM ORF encoded a peptide of 113 amino acids containing three EF-hand calcium-binding domains, its expression level was highest in the mantle, hinting that the cgCaM gene is probably involved in shell formation of Pacific oyster, and the common ancestor of Gastropoda and Bivalvia may possess at least three CaM genes. We also found that the numbers of some EF hand family members in highly calcified species were higher than those in lowly calcified species and the numbers of these motifs in oyster genome were the highest among the mollusk species with whole genome sequence, further hinting the correlation between CaM and biomineralization. PMID:27703977

  4. Diet shifts of lesser scaup are consistent with the spring condition hypothesis

    USGS Publications Warehouse

    Anteau, M.J.; Afton, A.D.

    2006-01-01

    We compared diets of lesser scaup (Aythya affinis (Eyton, 1838)) in the springs of 2000 and 2001 to those reported in the 1970s and the 1980s to determine whether forage quality has declined as predicted by the spring condition hypothesis. In Minnesota, we found that the current aggregate percentage of Amphipoda (an important food item) in lesser scaup diets was 94% lower than that reported from the same locations in the 1980s. Current mean individual prey mass of Amphipoda and Bivalvia in Minnesota were 86.6% and 85.1% lower than historical levels, respectively. In Manitoba, current aggregate percentages of Trichoptera and Chaoboridae in lesser scaup diets (1% and 0%, respectively) were lower than those reported from the same location in the 1970s (14% and 2%, respectively), whereas the percentage of Chironomidae (40%) was higher than that of historical levels (19%). Current mean individual prey mass of all insects, seeds, Chironomidae, and Zygoptera in Manitoba were 63.5%, 65.4%, 44.1%, and 44.9% lower than those of historical levels, respectively. The observed dietary shift from Amphipoda to less nutritious prey in Minnesota, coupled with lower mean individual prey mass in both locations, likely constitutes lower forage quality in lesser scaup diets, which is consistent with the spring condition hypothesis. ?? 2006 NRC.

  5. The evolutionary origins of the southern ocean Philobryid bivalves: hidden biodiversity, ancient persistence.

    PubMed

    Jackson, Jennifer A; Linse, Katrin; Whittle, Rowan; Griffiths, Huw J

    2015-01-01

    Philobryids (Bivalvia: Arcoida) are one of the most speciose marine bivalve families in the Southern Ocean and are common throughout the Southern Hemisphere. Considering this diversity and their brooding reproductive mode (limiting long-distance dispersal), this family may have been present in the Southern Ocean since its inception. However Philobrya and Adacnarca appear only in the Quaternary fossil record of the Antarctic, suggesting a much more recent incursion. Molecular dating provides an independent means of measuring the time of origin and radiation of this poorly known group. Here we present the first combined molecular and morphological investigation of the Philobryidae in the Southern Ocean. Two nuclear loci (18S and 28S) were amplified from 35 Southern Ocean Adacnarca and Philobrya specimens, with a combined sequence length of 2,282 base pairs (bp). Adacnarca specimens (A. nitens and A. limopsoides) were resolved as a strongly supported monophyletic group. Genus Philobrya fell into two strongly supported groups ('sublaevis' and 'magellanica/wandelensis'), paraphyletic with Adacnarca. The A. nitens species complex is identified as at least seven morpho-species through morphological and genetic analysis of taxon clustering. Phylogenetic analyses resolve Philobryidae as a strongly supported monophyletic clade and sister taxon to the Limopsidae, as anticipated by their classification into the superfamily Limopsoidea. Bayesian relaxed clock analyses of divergence times suggest that genus Adacnarca radiated in the Southern Ocean from the Early Paleogene, while P. sublaevis and P. wandelensis clades radiated in the late Miocene, following the formation of the Antarctic Circumpolar Current.

  6. Demonstration of nutrient pathway from the digestive system to oocytes in the gonad intestinal loop of the scallop Pecten maximus L.

    PubMed

    Beninger, Peter G; Le Pennec, Gaël; Le Pennec, Marcel

    2003-08-01

    The mechanism of nutrient transfer from the digestive system to the gonad acini and developing oocytes was investigated in the gonad-intestinal loop system of the queen scallop Pecten maximus L. Ferritin was injected directly into the purged intestine of specimens from the wild. Subsequently, a histochemical reaction and transmission electron microscopy were used to localize ferritin in various cell types. Ferritin was rapidly absorbed by the intestinal epithelium, and then appeared in hemocytes in the surrounding connective tissue. In the hemocytes, ferritin was stored in variously sized inclusions, as well as in the general cytoplasm. In all sections examined for the 12 experimental individuals, hemocytes were always found in association with connective tissue fibers extending from the base of the intestinal epithelium to gonad acini. After 30-min incubation, ferritin appeared inside the acini of all individuals. Ferritin-bearing cells were rarely found in association with male acini or gametes, nor with mature female gametes, but often with developing female gametes. Not all individuals showed the same temporal dynamics of ferritin transport, suggesting that nutrient transfer to oocytes is either not a continuous process, or that among individuals, transfer is not synchronized on short time scales. This is the first demonstration of a pathway of nutrient transfer from the intestine, and more generally the digestive system, to developing oocytes in the Bivalvia.

  7. Tolerance values of benthic macroinvertebrates for stream biomonitoring: assessment of assumptions underlying scoring systems worldwide.

    PubMed

    Chang, Feng-Hsun; Lawrence, Justin E; Rios-Touma, Blanca; Resh, Vincent H

    2014-04-01

    Tolerance values (TVs) based on benthic macroinvertebrates are one of the most widely used tools for monitoring the biological impacts of water pollution, particularly in streams and rivers. We compiled TVs of benthic macroinvertebrates from 29 regions around the world to test 11 basic assumptions about pollution tolerance, that: (1) Arthropoda are < tolerant than non-Arthropoda; (2) Insecta < non-Insecta; (3) non-Oligochaeta < Oligochaeta; (4) other macroinvertebrates < Oligochaeta + Chironomidae; (5) other macroinvertebrate taxa < Isopoda + Gastropoda + Hirudinea; (6) Ephemeroptera + Plecoptera + Trichoptera (EPT) < Odonata + Coleoptera + Heteroptera (OCH); (7) EPT < non-EPT insects; (8) Diptera < Insecta; (9) Bivalvia < Gastropoda; (10) Baetidae < other Ephemeroptera; and (11) Hydropsychidae < other Trichoptera. We found that the first eight of these 11 assumptions were supported despite regional variability. In addition, we examined the effect of Best Professional Judgment (BPJ) and non-independence of TVs among countries by performing all analyses using subsets of the original dataset. These subsets included a group based on those systems using TVs that were derived from techniques other than BPJ, and groups based on methods used for TV assignment. The results obtained from these subsets and the entire dataset are similar. We also made seven a priori hypotheses about the regional similarity of TVs based on geography. Only one of these was supported. Development of TVs and the reporting of how they are assigned need to be more rigorous and be better described.

  8. Quantitative proteomics of heavy metal stress responses in Sydney rock oysters.

    PubMed

    Muralidharan, Sridevi; Thompson, Emma; Raftos, David; Birch, Gavin; Haynes, Paul A

    2012-03-01

    Currently, there are few predictive biomarkers in key biomonitoring species, such as oysters, that can detect heavy metal pollution in coastal waterways. Several attributes make oysters superior to other organisms for positive biomonitoring of heavy metal pollution. In particular, they are filter feeders with a high capacity for bioaccumulation. In this study, we used two proteomics approaches, namely label-free shotgun proteomics based on SDS-PAGE gel separation and gas phase fractionation, to investigate the heavy metal stress responses of Sydney rock oysters. Protein samples were prepared from haemolymph of oysters exposed to 100 μg/L of PbCl(2), CuCl(2), or ZnCl(2) for 4 days in closed aquaria. Peptides were identified using a Bivalvia protein sequence database, due to the unavailability of a complete oyster genome sequence. Statistical analysis revealed 56 potential biomarker proteins, as well as several protein biosynthetic pathways to be greatly impacted by metal stress. These have the potential to be incorporated into bioassays for prevention and monitoring of heavy metal pollution in Australian oyster beds. The study confirms that proteomic analysis of biomonitoring species is a promising approach for assessing the effects of environmental pollution, and our experiments have provided insights into the molecular mechanisms underlying oyster stress responses.

  9. Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin

    PubMed Central

    Aquilina, Alfred; Woulds, Clare; Glover, Adrian G.; Little, Crispin T. S.; Hepburn, Laura E.; Newton, Jason; Mills, Rachel A.

    2016-01-01

    Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250 m depth and report data from a series of geochemical and biological analyses. Here, the geochemical signatures were consistent with weak methane seepage and the role of sub-surface methane consumption was clearly very important, preventing gas emissions into bottom waters. As a result, the contribution of methane-derived carbon to the microbial and metazoan food webs was very limited, although sulfur isotopic signatures indicated a wider range of dietary contributions than was apparent from carbon isotope ratios. Macrofaunal assemblages had high dominance and were indicative of reducing sediments, with many taxa common to other similar environments and no seep-endemic fauna, indicating transitional assemblages. Also similar to other cold seep areas, there were samples of authigenic carbonate, but rather than occurring as pavements or sedimentary concretions, these carbonates were restricted to patches on the shells of Axinulus antarcticus (Bivalvia, Thyasiridae), which is suggestive of microbe–metazoan interactions. PMID:27703692

  10. Vertically oriented structure and its fracture behavior of the Indonesia white-pearl oyster.

    PubMed

    Chen, Guowei; Luo, Hongyun; Luo, Shunfei; Lin, Zhenying; Ma, Yue

    2017-02-01

    Structural calcites, aragonites, and the bonding organic network decide the growth, structure and mechanical properties of the mollusk bivalvia shell. Here, it was found out that the calcite prisms together with the coated organics construct another kind of 'brick and mortar' structure similar to the aragonite tablets. The calcite layer can be divided into three sublayers and direct evidences show that the calcite prisms are produced by two methods: nucleation and growing in the first sublayer; or fusing from the aragonites, which is quite different from some previous reports. The crystallographic orientation, micro hardness and crack propagations were tested and observed by XRD, micro harness tester, SEM and TEM. Submicron twin crystals were observed in the immature aragonite tablets. The fracture processes and the micro deformation of the aragonite tablets are detected by acoustic emission (AE) in the tensile tests, which gave the interpretation of the dynamical fracture processes: plastic deformation and fracture of the organics, and friction of the minerals at the first two stages; wear and fracture of the minerals at the third stage. Calcites and aragonites are combined and working together, like two layers of vertical 'brick and mortar's, ensuring the stable mechanical properties of the whole shell.

  11. Ross Sea Mollusca from the Latitudinal Gradient Program: R/V Italica 2004 Rauschert dredge samples.

    PubMed

    Ghiglione, Claudio; Alvaro, Maria Chiara; Griffiths, Huw J; Linse, Katrin; Schiaparelli, Stefano

    2013-01-01

    Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP) on board the R/V "Italica" in the Ross Sea (Antarctica) in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500μm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data). Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species), 1,323 were Bivalvia (accounting for 36 species), 949 were Aplacophora (accounting for 7 species), 74 specimens were Scaphopoda (3 species), 38 were Monoplacophora (1 species) and, finally, 10 specimens were Polyplacophora (1 species). This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA), Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project "BAMBi" (PNRA 2010/A1.10).

  12. Amundsen Sea Mollusca from the BIOPEARL II expedition.

    PubMed

    Moreau, Camille; Linse, Katrin; Griffiths, Huw; Barnes, David; Kaiser, Stefanie; Glover, Adrian; Sands, Chester; Strugnell, Jan; Enderlein, Peter; Geissler, Paul

    2013-01-01

    Information regarding the molluscs in this dataset is based on the epibenthic sledge (EBS) samples collected during the cruise BIOPEARL II / JR179 RRS James Clark Ross in the austral summer 2008. A total of 35 epibenthic sledge deployments have been performed at five locations in the Amundsen Sea at Pine Island Bay (PIB) and the Amundsen Sea Embayment (ASE) at depths ranging from 476 to 3501m. This presents a unique and important collection for the Antarctic benthic biodiversity assessment as the Amundsen Sea remains one of the least known regions in Antarctica. Indeed the work presented in this dataset is based on the first benthic samples collected with an EBS in the Amundsen Sea. However we assume that the data represented are an underestimation of the real fauna present in the Amundsen Sea. In total 9261 specimens belonging to 6 classes 55 families and 97 morphospecies were collected. The species richness per station varied between 6 and 43. Gastropoda were most species rich 50 species followed by Bivalvia (37), Aplacophora (5), Scaphopoda (3) and one from each of Polyplacophora and Monoplacophora.

  13. High expression of new genes in trochophore enlightening the ontogeny and evolution of trochozoans

    PubMed Central

    Xu, Fei; Domazet-Lošo, Tomislav; Fan, Dingding; Dunwell, Thomas L.; Li, Li; Fang, Xiaodong; Zhang, Guofan

    2016-01-01

    Animals with trochophore larvae belong to Trochozoa, one of the main branches of Bilateria. In addition to exhibiting spiral cleavage and early cell fate determination, trochozoans typically undergo indirect development, which contributes to the most unique characteristics of their ontogeny. The indirect development of trochozoans has provoked discussion regarding the origin and evolution of marine larvae and is interesting from the perspective of phylogeny-ontogeny correspondence. While these phylo-onto correlations have an hourglass shape in Deuterostomia, Ecdysozoa, plants and even fungi, they have seldom been studied in Trochozoa, and even Lophotrochozoa. Here, we compared the ontogenetic transcriptomes of the Pacific oyster, Crassostrea gigas (Bivalvia, Mollusca), the Pacific abalone, Haliotis discus hannai (Gastropoda, Mollusca), and the sand worm Perinereis aibuhitensis (Polychaeta, Annelida) using several complementary phylotranscriptomic methods to examine their evolutionary trajectories. The results revealed the late trochophore stage as the phylotypic phase. However, this basic pattern is accompanied with increased use of new genes in the trochophore stages which marks specific adaptations of the larval body plans. PMID:27698463

  14. Meiofauna associated with a Pacific coral reef in Costa Rica

    NASA Astrophysics Data System (ADS)

    Guzmán, Héctor M.; Obando, Vilma L.; Cortés, Jorge

    1987-10-01

    The meiofauna of two coral reef habitats at Isla del Naño, Costa Rica was studied over a one year period. The dominant groups were: Foraminifera (21.2%), Copepoda (19.7%), Nematoda (19.1%), Gastropoda (16.5%), Polychaeta (7.2%) and Bivalvia (6.6%). The highest diversity was found in coarse, heterogeneous sands with the highest percentage of carbonates. The meiofauna showed a high degree of horizontal aggregation, which is a characteristic pattern for macro- and meiofauna in sediments of variable composition. No vertical variation in distribution was evident, probably due to the deep location of the Redox Potential Discontinuity layer. The total densities of organisms found in this study (99 to 575 ind/10 cm2) are low compared with densities in similar non-reefal sands (7 to 6116), and from fine sediments (80 to 17 000), but are comparable to densities found in other reef areas (39 to 609.5 ind/10 cm2). This is the first report on meiofauna from the eastern Pacific, and the first time that foraminiferans are the dominant group.

  15. Arsenic toxicity: a heart-breaking saga of a freshwater mollusc.

    PubMed

    Chakraborty, Sudipta; Ray, Mitali; Ray, Sajal

    2012-06-01

    The freshwater wetland systems of India is a complex habitat that supports a broad range of diverse species including molluscs, which play an important role in supplementing third world countries. In the arsenic affected flood plains of West Bengal, a huge amount of arsenic laden groundwater is raised for the purpose of irrigation. Agricultural runoffs and flood water movement during monsoon may cause accumulation of arsenic in the adjacent freshwater aquifers, the common habitat of Lamellidens marginalis (Mollusca; Bivalvia; Eulamellibranchiata), a filter feeder, sensitive to altered environmental conditions. To examine the nature of toxicity induced by inorganic arsenic on both the haemocytes and tissues of the invertebrate heart, the animals were exposed to five different sublethal concentrations of sodium arsenite for a maximum time span of 30 days in vitro. Significant differences were recorded in the total haemocyte count, biochemical and histopathological parameters of the heart of L. marginalis under the arsenic induced stress. Our observations indicate the development of profound haematopoietic and cardiac stress under the sublethal inorganic arsenite exposure and it also implies the nature of risk imposed on the freshwater aquatic ecosystem under potential arsenic contamination.

  16. Eco-environmental impact assessment of pre-leisure beach nourishment on the benthic invertebrate community at Anping coast

    NASA Astrophysics Data System (ADS)

    Shih, Chun-Han; Kuo, Yi-Yu; Chu, Ta-Jen; Chou, Wen-Chieh; Chang, Wei-Tse; Lee, Ying-Chou

    2011-06-01

    In recent years, owing to global warming and the rising sea levels, beach nourishment and groin building have been increasingly employed to protect coastal land from shoreline erosion. These actions may degrade beach habitats and reduce biomass and invertebrate density at sites where they were employed. We conducted an eco-environmental evaluation at the Anping artificial beach-nourishment project area. At this site, sand piles within a semi-enclosed spur groin have been enforced by use of eco-engineering concepts since 2003. Four sampling sites were monitored during the study period from July 2002 to September 2008. The environmental impact assessment and biological investigations that we conducted are presented here. The results from this study indicate that both biotic (number of species, number of individual organisms, and Shannon-Wiener diversity) and abiotic parameters (suspended solids, biological oxygen demand, chemical oxygen demand, dissolved inorganic nitrogen, dissolved inorganic phosphorus, total phosphorus, total organic carbon, median diameter, and water content) showed significant differences before and after beach engineering construction. Biological conditions became worse in the beginning stages of the engineering but improved after the restoration work completion. This study reveals that the composition of benthic invertebrates changed over the study period, and two groups of organisms, Bivalvia and Gastropoda, seemed to be particularly suitable to this habitat after the semi-enclosed artificial structures completion.

  17. Into the deep: a phylogenetic approach to the bivalve subclass Protobranchia.

    PubMed

    Sharma, Prashant P; Zardus, John D; Boyle, Elizabeth E; González, Vanessa L; Jennings, Robert M; McIntyre, Erin; Wheeler, Ward C; Etter, Ron J; Giribet, Gonzalo

    2013-10-01

    A molecular phylogeny of Protobranchia, the subclass of bivalve mollusks sister to the remaining Bivalvia, has long proven elusive, because many constituent lineages are deep-sea endemics, which creates methodological challenges for collecting and preserving genetic material. We obtained 74 representatives of all 12 extant protobranch families and investigated the internal phylogeny of this group using sequence data from five molecular loci (16S rRNA, 18S rRNA, 28S rRNA, cytochrome c oxidase subunit I, and histone H3). Model-based and dynamic homology parsimony approaches to phylogenetic reconstruction unanimously supported four major clades of Protobranchia, irrespective of treatment of hypervariable regions in the nuclear ribosomal genes 18S rRNA and 28S rRNA. These four clades correspond to the superfamilies Nuculoidea (excluding Sareptidae), Nuculanoidea (including Sareptidae), Solemyoidea, and Manzanelloidea. Salient aspects of the phylogeny include (1) support for the placement of the family Sareptidae with Nuculanoidea; (2) the non-monophyly of the order Solemyida (Solemyidae+Nucinellidae); (3) and the non-monophyly of most nuculoid and nuculanoid genera and families. In light of this first family-level phylogeny of Protobranchia, we present a revised classification of the group. Estimation of divergence times in concert with analyses of diversification rates demonstrate the signature of the end-Permian mass extinction in the phylogeny of extant protobranchs.

  18. Phylogenomics reveals deep molluscan relationships

    PubMed Central

    Kocot, Kevin M.; Cannon, Johanna T.; Todt, Christiane; Citarella, Mathew R.; Kohn, Andrea B.; Meyer, Achim; Santos, Scott R.; Schander, Christoffer; Moroz, Leonid L.; Lieb, Bernhard; Halanych, Kenneth M.

    2014-01-01

    Evolutionary relationships among the eight major lineages of Mollusca have remained unresolved despite their diversity and importance. Previous investigations of molluscan phylogeny, based primarily on nuclear ribosomal gene sequences1–3 or morphological data4, have been unsuccessful at elucidating these relationships. Recently, phylogenomic studies using dozens to hundreds of genes have greatly improved our understanding of deep animal relationships5. However, limited genomic resources spanning molluscan diversity has prevented use of a phylogenomic approach. Here we use transcriptome and genome data from all major lineages (except Monoplacophora) and recover a well-supported topology for Mollusca. Our results strongly support the Aculifera hypothesis placing Polyplacophora (chitons) in a clade with a monophyletic Aplacophora (worm-like molluscs). Additionally, within Conchifera, a sister-taxon relationship between Gastropoda and Bivalvia is supported. This grouping has received little consideration and contains most (>95%) molluscan species. Thus we propose the node-based name Pleistomollusca. In light of these results, we examined the evolution of morphological characters and found support for advanced cephalization and shells as possibly having multiple origins within Mollusca. PMID:21892190

  19. Assessing the fidelity of the fossil record by using marine bivalves

    PubMed Central

    Valentine, James W.; Jablonski, David; Kidwell, Susan; Roy, Kaustuv

    2006-01-01

    Taxa that fail to become incorporated into the fossil record can reveal much about the biases of this record and provide the information needed to correct such biases in empirical analyses of the history of life. Yet little is known about the characteristics of taxa missing from the fossil record. For the marine Bivalvia, which have become a model system for macroevolutionary and macroecological analysis in the fossil record, 308 of the 1,292 living genera and subgenera (herein termed “taxa”) are not recorded as fossils. These missing taxa are not a random sample of the clade, but instead tend to have small body size, reactive shell structures, commensal or parasitic habit, deep-sea distribution, narrow geographic range, restriction to regions exposing few Neogene marine sediments, or recent date of formal taxonomic description in the neontological literature. Most missing taxa show two or more of these features and tend to be concentrated in particular families. When we exclude the smallest taxa (<1 cm) and deep-sea endemics, date of published description and geographic range become the strongest predictors of the missing taxa; other factors are statistically insignificant or have relatively small effects. These biases might influence a variety of analyses including the use of fossil data in support of phylogenetic analyses, molecular clock calibrations, and analyses of spatial and temporal dynamics of clades and biotas. Clade inventories such as these can be used to develop protocols that minimize the biases imposed by sampling and preservation. PMID:16617108

  20. Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin

    NASA Astrophysics Data System (ADS)

    Bell, James B.; Aquilina, Alfred; Woulds, Clare; Glover, Adrian G.; Little, Crispin T. S.; Reid, William D. K.; Hepburn, Laura E.; Newton, Jason; Mills, Rachel A.

    2016-09-01

    Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250 m depth and report data from a series of geochemical and biological analyses. Here, the geochemical signatures were consistent with weak methane seepage and the role of sub-surface methane consumption was clearly very important, preventing gas emissions into bottom waters. As a result, the contribution of methane-derived carbon to the microbial and metazoan food webs was very limited, although sulfur isotopic signatures indicated a wider range of dietary contributions than was apparent from carbon isotope ratios. Macrofaunal assemblages had high dominance and were indicative of reducing sediments, with many taxa common to other similar environments and no seep-endemic fauna, indicating transitional assemblages. Also similar to other cold seep areas, there were samples of authigenic carbonate, but rather than occurring as pavements or sedimentary concretions, these carbonates were restricted to patches on the shells of Axinulus antarcticus (Bivalvia, Thyasiridae), which is suggestive of microbe-metazoan interactions.

  1. Diets and trophic-guild structure of a diverse fish assemblage in Chesapeake Bay, U.S.A.

    PubMed

    Buchheister, A; Latour, R J

    2015-03-01

    Dietary habits and trophic-guild structure were examined in a fish assemblage (47 species) of the Chesapeake Bay estuary, U.S.A., using 10 years of data from >25 000 fish stomachs. The assemblage was comprised of 10 statistically significant trophic guilds that were principally differentiated by the relative amounts of Mysida, Bivalvia, Polychaeta, Teleostei and other Crustacea in the diets. These guilds were broadly aggregated into five trophic categories: piscivores, zooplanktivores, benthivores, crustacivores and miscellaneous consumers. Food web structure was largely dictated by gradients in habitat (benthic to pelagic) and prey size. Size classes within piscivorous species were more likely to be classified into different guilds, reflecting stronger dietary changes through ontogeny relative to benthivores and other guilds. Relative to predator species and predator size, the month of sampling had negligible effects on dietary differences within the assemblage. A majority of sampled fishes derived most of their nutrition from non-pelagic prey sources, suggesting a strong coupling of fish production to benthic and demersal food resources. Mysida (predominantly the opossum shrimp Neomysis americana) contributed substantially to the diets of over 25% of the sampled predator groups, indicating that this species is a critical, but underappreciated, node in the Chesapeake Bay food web.

  2. Amundsen Sea Mollusca from the BIOPEARL II expedition

    PubMed Central

    Moreau, Camille; Linse, Katrin; Griffiths, Huw; Barnes, David; Kaiser, Stefanie; Glover, Adrian; Sands, Chester; Strugnell, Jan; Enderlein, Peter; Geissler, Paul

    2013-01-01

    Abstract Information regarding the molluscs in this dataset is based on the epibenthic sledge (EBS) samples collected during the cruise BIOPEARL II / JR179 RRS James Clark Ross in the austral summer 2008. A total of 35 epibenthic sledge deployments have been performed at five locations in the Amundsen Sea at Pine Island Bay (PIB) and the Amundsen Sea Embayment (ASE) at depths ranging from 476 to 3501m. This presents a unique and important collection for the Antarctic benthic biodiversity assessment as the Amundsen Sea remains one of the least known regions in Antarctica. Indeed the work presented in this dataset is based on the first benthic samples collected with an EBS in the Amundsen Sea. However we assume that the data represented are an underestimation of the real fauna present in the Amundsen Sea. In total 9261 specimens belonging to 6 classes 55 families and 97 morphospecies were collected. The species richness per station varied between 6 and 43. Gastropoda were most species rich 50 species followed by Bivalvia (37), Aplacophora (5), Scaphopoda (3) and one from each of Polyplacophora and Monoplacophora. PMID:23794869

  3. Thiaminase activity in native freshwater mussels

    USGS Publications Warehouse

    Blakeslee, Carrie J.; Sweet, Stephanie; Galbraith, Heather S.; Honeyfield, Dale C.

    2015-01-01

    Thiamine (vitamin B1) deficiency in the Great Lakes has been attributed to elevated levels of thiaminase I enzyme activity in invasive prey species; however, few studies have investigated thiaminase activity in native prey species. Some of the highest levels of thiaminase activity have been measured in invasive dreissenid mussels with little understanding of background levels contributed by native freshwater mussels (Bivalvia: Unionidae). In this study, thiaminase activity was measured in two freshwater mussel species, Elliptio complanata and Strophitus undulatus, from the Delaware and Susquehanna River drainage basins located in north eastern United States. Thiaminase activity was also measured in gravid and non-gravid S. undulatus. Average thiaminase activity differed significantly between species (7.2 and 42.4 μmol/g/min, for E. complanata and S. undulatus respectively) with no differences observed between drainage basins. Gravid S. undulatus had significantly lower thiaminase activity (28.0 μmol/g/min) than non-gravid mussels (42.4 μmol/g/min). Our results suggest that a suite of factors may regulate thiaminase activity in freshwater mussels and that native freshwater mussel thiaminase activity is within the range observed for invasive dreissenids. These results add to our understanding of the complexities in identifying the ecological conditions that set the stage for thiamine deficiency.

  4. Ross Sea Mollusca from the Latitudinal Gradient Program: R/V Italica 2004 Rauschert dredge samples

    PubMed Central

    Ghiglione, Claudio; Alvaro, Maria Chiara; Griffiths, Huw J.; Linse, Katrin; Schiaparelli, Stefano

    2013-01-01

    Abstract Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP) on board the R/V “Italica” in the Ross Sea (Antarctica) in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500μm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data). Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species), 1,323 were Bivalvia (accounting for 36 species), 949 were Aplacophora (accounting for 7 species), 74 specimens were Scaphopoda (3 species), 38 were Monoplacophora (1 species) and, finally, 10 specimens were Polyplacophora (1 species). This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA), Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project “BAMBi” (PNRA 2010/A1.10). PMID:24146597

  5. [Increase functions of the type dW/dt=k Wm/(t + to)p and their integrals (author's transl)].

    PubMed

    Sager, G

    1980-01-01

    The testing of a dozen functions for the length of the Alaskan razor clam Siliqua Patula (Bivalvia) by the author (Sager 1980) has given the best results when applying the increase ansatz dW/dt=k Wm/tp proposed after a series of investigations into mathematical properties of organic growth (Sager 1979a). The resulting growth function is restricted to vanishing values of the birth length however as is practically the case with the razor clam measuring 0,01 cm at birth and reaching 15 to 16 cm after at least 12 years of age. When the quotient of initial and final length or weight will go up with changing to other species in future investigations, the increase function must be extended to dW/dt=k Wm/(t + to)p, giving quite different solutions for m = 1 and 0 < m < infinity but m not equal to 1 respectively. The properties of the growth functions are discussed, and the evaluation of the parameters shown putting speical attention to the influence of to.

  6. Analysis of ITS1 and ITS2 sequences in Ensis razor shells: suitability as molecular markers at the population and species levels, and evolution of these ribosomal DNA spacers.

    PubMed

    Vierna, Joaquín; Martínez-Lage, Andrés; González-Tizón, Ana M

    2010-01-01

    Internal transcribed spacer 1 and 2 (ITS1 and ITS2) sequences were analysed in Ensis razor shells (Mollusca: Bivalvia: Pharidae). We aimed to (1) test ITS1 and ITS2 as molecular markers at the population level in the successful alien E. directus (Conrad, 1843); (2) test these spacers at the species level in E. directus and three other Ensis species, E. siliqua (L., 1758), E. macha (Molina, 1782), and E. magnus (Schumacher, 1817); and (3) analyse the evolutionary processes that may be shaping Ensis ITS1 and ITS2 extant variation. In E. directus, despite the intragenomic divergence detected, ITS1 and ITS2 were informative in differentiating the geographic areas considered (Denmark and Canada) by means of both the insertion-deletion polymorphism and the nucleotide polymorphism. In this species, the 5.8S ribosomal gene (5.8S) showed scarce polymorphism. At the species level, maximum parsimony and maximum likelihood analyses revealed that ITS1 and ITS2 may be suitable to reconstruct Ensis phylogenetic relationships. Finally, the evolutionary models that best fit the long-term evolution of Ensis ITS1-5.8S-ITS2 are discussed. A mixed process of concerted evolution, birth-and-death evolution, and selection is chosen as an option that may reconcile the long-term evolution of Ensis ITS1-5.8S-ITS2 and 5S ribosomal DNA.

  7. Mercury content in tinned molluscs (mussel, cockle, variegated scallop, and razor shell) normally consumed in Spain, 2005.

    PubMed

    Gutiérrez, Angel José; Lozano, Gonzalo; González, Tomás; Ignacio Reguera, Juan; Hardisson, Arturo

    2006-09-01

    Concentrations of mercury were determined for tinned molluscs (Mollusca, Bivalvia), i.e., mussels (Mytilus spp.), cockles (Cerastoderma edule), variegated scallops (Chlamys varia), and razor shells (Ensis spp.), consumed in Spain. A total of 220 samples were analyzed: 120 mussels, 40 cockles, 24 variegated scallops, and 36 razor shells. Samples were obtained weekly from markets in Santa Cruz de Tenerife (Canary Islands) over a period of 12 months. All observed concentrations of mercury were below the maximum permitted for human consumption (0.5 mg/kg) as defined by European Community Decision 93/ 351/CE. Mercury concentrations were 27.28 +/- 12.43 microg/kg for mussels, 66.59 +/- 23.53 microg/kg for cockles, 33.68 +/- 15.76 microg/kg for variegated scallops, and 21.26 +/- 12.24 microg/kg for razor shells. To evaluate the importance of mercury as a food contaminant, the percentage ingested daily, the weight of mercury in the diet, and the calculated percentage of this metal in the diet contributed by reference species were estimated.

  8. Modeling bivalve diversification: the effect of interaction on a macroevolutionary system

    NASA Technical Reports Server (NTRS)

    Miller, A. I.; Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)

    1988-01-01

    The global diversification of the class Bivalvia has historically received two conflicting interpretations. One is that a major upturn in diversification was associated with, and a consequence of, the Lake Permian mass extinction. The other is that mass extinctions have had little influence and that bivalves have experienced slow but nearly steady exponential diversification through most of their history, unaffected by interactions with other clades. We find that the most likely explanation lies between these two interpretations. Through most of the Phanerozoic, the diversity of bivalves did indeed exhibit slow growth, which was not substantially altered by mass extinctions. However, the presence of "hyperexponential bursts" in diversification during the initial Ordovician radiation and following the Late Permian and Late Cretaceous mass extinctions suggests a more complex history in which a higher characteristic diversification rate was dampened through most of the Phanerozoic. The observed pattern can be accounted for with a two-phase coupled (i.e., interactive) logistic model, where one phase is treated as the "bivalves" and the other phase is treated as a hypothetical group of clades with which the "bivalves" might have interacted. Results of this analysis suggest that interactions with other taxa have substantially affected bivalve global diversity through the Phanerozoic.

  9. Molecular Cloning and Characterization of Full-Length cDNA of Calmodulin Gene from Pacific Oyster Crassostrea gigas.

    PubMed

    Li, Xing-Xia; Yu, Wen-Chao; Cai, Zhong-Qiang; He, Cheng; Wei, Na; Wang, Xiao-Tong; Yue, Xi-Qing

    2016-01-01

    The shell of the pearl oyster (Pinctada fucata) mainly comprises aragonite whereas that of the Pacific oyster (Crassostrea gigas) is mainly calcite, thereby suggesting the different mechanisms of shell formation between above two mollusks. Calmodulin (CaM) is an important gene for regulating the uptake, transport, and secretion of calcium during the process of shell formation in pearl oyster. It is interesting to characterize the CaM in oysters, which could facilitate the understanding of the different shell formation mechanisms among mollusks. We cloned the full-length cDNA of Pacific oyster CaM (cgCaM) and found that the cgCaM ORF encoded a peptide of 113 amino acids containing three EF-hand calcium-binding domains, its expression level was highest in the mantle, hinting that the cgCaM gene is probably involved in shell formation of Pacific oyster, and the common ancestor of Gastropoda and Bivalvia may possess at least three CaM genes. We also found that the numbers of some EF hand family members in highly calcified species were higher than those in lowly calcified species and the numbers of these motifs in oyster genome were the highest among the mollusk species with whole genome sequence, further hinting the correlation between CaM and biomineralization.

  10. A seasonal comparison of zooplankton communities in the Kara Sea - With special emphasis on overwintering traits

    NASA Astrophysics Data System (ADS)

    Kosobokova, Ksenia Nikolaevna; Hirche, Hans-Juergen

    2016-06-01

    Siberian marginal seas cover large parts of the marine Arctic and host unique zooplankton communities. Detailed knowledge of their community structure and life history traits is a prerequisite to predict their response to ongoing and future climate and anthropogenic changes although winter data is extremely rare. Here data are presented from winter samples (February and April) in four biogeographic regions of the Kara Sea. Comparison of community composition and zooplankton abundance/biomass with data collected during summer showed lower diversity in winter, mainly due to the absence of freshwater species. In contrast to many other northern regions, seasonal biomass differences were relatively small. Year-round high biomass is maintained through a large share of small copepod species and constantly high share of the chaetognath Parasagitta elegans. An advanced state of gonad maturation and reproduction was observed in winter in herbivorous, omnivorous, and carnivorous species, e.g. the copepods Calanus glacialis, Drepanopus bungei, Limnocalanus macrurus, Oithona similis, Pseudocalanus major, Pseudocalanus minutus/acuspes, Paraeuchaeta glacialis, Microcalanus pygmaeus, and euphausiids, hydromedusae, and pteropods. Meroplanktonic larvae of nudibranchia, polychaeta and bivalvia were also registered. Close to the Yenisei mouth, abundance of eggs and larvae of various taxa exceeded older stages. Our data show that the brackish-water zone of the Kara Sea hosts specific communities with omnivorous species efficiently exploiting local resources during the winter and utilizing them for winter reproduction.

  11. Age and paleoenvironmental significance of mega-invertebrates from the "San Pedro" Formation in the Coyote Hills, Fullerton and Buena Park, Orange County, Southern California

    USGS Publications Warehouse

    Powell, Charles L.; Stevens, Dave

    2000-01-01

    The "San Pedro" Formation in the Coyote Hills contains an invertebrate fossil as-semblage of 184 taxa from 158 localities. The fauna consists of two annelids, 174 mollusks (80 bivalves, 94 gastropods, and three scaphopods), five arthropods, and three echinoids, along with other minor constituents recognized by not specifically identified during the present study. These fossils are divided into three assemblages; 1) a lower, Pliocene assemblage (which may not differ ecologically from the middle fauna), 2) a middle, cool water assemblage, and 3) an upper, temperate to warm water. These fossils suggest a probably late Pliocene to early Pleistocene age for outcrops of the "San Pedro" Formation in the Coyote Hills. A fourth assemblage with a limited, restricted marine fauna occurs in the overlying Coyote Hills Formation. The occurrence of Solamen columbianum (Dall) (Mollusca: Bivalvia) in the "San Pedro" Formation of the Coyote Hills marks its first occurrence as a fossil. The oldest fossil occurrence of the gastropods Tegula pulligo (Gmelin), questionably Haliotis cracherodii Leach, and the crustacean Randallia ornata (Randell) occurs in the "San Pedroï" Formation in the Coyote Hills.

  12. Potential retention effect at fish farms boosts zooplankton abundance

    NASA Astrophysics Data System (ADS)

    Fernandez-Jover, D.; Toledo-Guedes, K.; Valero-Rodríguez, J. M.; Fernandez-Gonzalez, V.; Sanchez-Jerez, P.

    2016-11-01

    Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on zooplankton assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total zooplankton capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10-20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant zooplankton groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in zooplankton taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of zooplankton at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues.

  13. Complete sequences of the highly rearranged molluscan mitochondrial genomes of the scaphopod graptacme eborea and the bivalve mytilus edulis

    SciTech Connect

    Boore, Jeffrey L.; Medina, Monica; Rosenberg, Lewis A.

    2004-01-31

    We have determined the complete sequence of the mitochondrial genome of the scaphopod mollusk Graptacme eborea (Conrad, 1846) (14,492 nts) and completed the sequence of the mitochondrial genome of the bivalve mollusk Mytilus edulis Linnaeus, 1758 (16,740 nts). (The name Graptacme eborea is a revision of the species formerly known as Dentalium eboreum.) G. eborea mtDNA contains the 37 genes that are typically found and has the genes divided about evenly between the two strands, but M. edulis contains an extra trnM and is missing atp8, and has all genes on the same strand. Each has a highly rearranged gene order relative to each other and to all other studied mtDNAs. G. eborea mtDNA has almost no strand skew, but the coding strand of M. edulis mtDNA is very rich in G and T. This is reflected in differential codon usage patterns and even in amino acid compositions. G. eborea mtDNA has fewer non-coding nucleotides than any other mtDNA studied to date, with the largest non-coding region being only 24 nt long. Phylogenetic analysis using 2,420 aligned amino acid positions of concatenated proteins weakly supports an association of the scaphopod with gastropods to the exclusion of Bivalvia, Cephalopoda, and Polyplacophora, but is generally unable to convincingly resolve the relationships among major groups of the Lophotrochozoa, in contrast to the good resolution seen for several other major metazoan groups.

  14. Mobile Element Evolution Playing Jigsaw—SINEs in Gastropod and Bivalve Mollusks

    PubMed Central

    Matetovici, Irina; Sajgo, Szilard; Ianc, Bianca; Ochis, Cornelia; Bulzu, Paul; Popescu, Octavian; Damert, Annette

    2016-01-01

    SINEs (Short INterspersed Elements) are widely distributed among eukaryotes. Some SINE families are organized in superfamilies characterized by a shared central domain. These central domains are conserved across species, classes, and even phyla. Here we report the identification of two novel such superfamilies in the genomes of gastropod and bivalve mollusks. The central conserved domain of the first superfamily is present in SINEs in Caenogastropoda and Vetigastropoda as well as in all four subclasses of Bivalvia. We designated the domain MESC (Romanian for MElc—snail and SCoica—mussel) because it appears to be restricted to snails and mussels. The second superfamily is restricted to Caenogastropoda. Its central conserved domain—Snail—is related to the Nin-DC domain. Furthermore, we provide evidence that a 40-bp subdomain of the SINE V-domain is conserved in SINEs in mollusks and arthropods. It is predicted to form a stable stem-loop structure that is preserved in the context of the overall SINE RNA secondary structure in invertebrates. Our analysis also recovered short retrotransposons with a Long INterspersed Element (LINE)-derived 5′ end. These share the body and/or the tail with transfer RNA (tRNA)-derived SINEs within and across species. Finally, we identified CORE SINEs in gastropods and bivalves—extending the distribution range of this superfamily. PMID:26739168

  15. Development and application of the mollusc Arctica islandica as a paleoceanographic tool for the North Atlantic Ocean

    SciTech Connect

    Weidman, C.R.

    1995-09-01

    Until now there has been no tool comparable to corals for reconstructing long term high-resolution geochemical time-series for the colder, higher-latitude oceans. In this thesis, the long-lived (+100 years) boreal mollusc (Bivalvia) Arctica islandica is shown to be practical for this purpose in the northern North Atlantic Ocean. The evidence, compiled here, demonstrates that the carbonate shell of this species faithfully records the ambient dissolved inorganic carbon`s (DIC) radiocarbon ({Delta}{sup 14}C) concentration and accurately reflects the ambient temperature in its stable oxygen isotope ({delta}{sup 18}O) composition. However, the stable carbon isotope ({delta}{sup 13}C) composition of the A. islandica shell likely is not a good recorder of ambient DIC {delta}{sup 13}C, and likely responds to physiological controls. Four {Delta}{sup 14}C time histories are reconstructed from the annual bands of A. islandica shells for the higher-latitudes of the northern North Atlantic Ocean (from 41{degree}N to 70{degree}N).

  16. Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes

    NASA Astrophysics Data System (ADS)

    Quang, Ngo Xuan; Vanreusel, Ann; Smol, Nic; Chau, Nguyen Ngoc

    2010-12-01

    Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for meiobenthos sampling. Twelve major taxa of meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the meiobenthos range from 581 to 3168 inds/10 cm2. Nematodes always occupy the highest numbers with a percentage ranging from 64-99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora, and Oncholaimus. Although the biodiversity of the meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.

  17. Evaluation of the potential of the common cockle (Cerastoderma edule L.) for the ecological risk assessment of estuarine sediments: bioaccumulation and biomarkers.

    PubMed

    Lobo, Jorge; Costa, Pedro M; Caeiro, Sandra; Martins, Marta; Ferreira, Ana M; Caetano, Miguel; Cesário, Rute; Vale, Carlos; Costa, Maria H

    2010-11-01

    Common cockles (Cerastoderma edule, L. 1758, Bivalvia: Cardiidae) were subjected to a laboratory assay with sediments collected from distinct sites of the Sado Estuary (Portugal). Cockles were obtained from a mariculture site of the Sado Estuary and exposed through 28-day, semi-static, assays to sediments collected from three sites of the estuary. Sediments from these sites revealed different physico-chemical properties and levels of metals and organic contaminants, ranging from unimpacted (the reference site) to moderately impacted, when compared to available sediment quality guidelines. Cockles were surveyed for bioaccumulation of trace elements (Ni, Cu, Zn, As, Cd and Pb) and organic contaminants (PAHs, PCBs and DDTs). Two sets of potential biomarkers were employed to assess toxicity: whole-body metallothionein (MT) induction and digestive gland histopathology. The bioaccumulation factor and the biota-to-soil accumulation factor were estimated as ecological indices of exposure to metals and organic compounds. From the results it is inferred that C. edule responds to sediment-bound contamination and might, therefore, be suitable for biomonitoring. The species was found capable to regulate and eliminate both types of contaminants. Still, the sediment contamination levels do not account for all the variation in bioaccumulation and MT levels, which may result from the moderate metal concentrations found in sediments, the species' intrinsic resistance to pollution and from yet unexplained xenobiotic interaction effects.

  18. A neurophylogenetic approach provides new insight to the evolution of Scaphopoda.

    PubMed

    Sumner-Rooney, Lauren H; Schrödl, Michael; Lodde-Bensch, Eva; Lindberg, David R; Heß, Martin; Brennan, Gerard P; Sigwart, Julia D

    2015-01-01

    The position of scaphopods in molluscan phylogeny remains singularly contentious, with several sister relationships supported by morphological and phylogenomic data: Scaphopoda + Bivalvia (Diasoma), Scaphopoda + Cephalopoda (Variopoda), and Scaphopoda + Gastropoda. Nervous system architecture has contributed significant insights to reconstructing phylogeny in the Mollusca and other invertebrate groups, but a modern neurophylogenetic approach has not been applied to molluscs, hampered by a lack of clearly defined homologous characters that can be unequivocally compared across the radical body plan disparity among the living clades. We present the first three-dimensional reconstruction of the anterior nervous system of a scaphopod, Rhabdus rectius, using histological tomography. We also describe a new putative sensory organ, a paired and pigmented sensory mantle slit. This structure is restricted to our study species and not a general feature of scaphopods, but it forms an integral part of the description of the nervous system in R. rectius. It also highlights the potential utility of neuro-anatomical characters for multiple levels of phylogenetic inference beyond this study. This potential has not previously been exploited for the thorny problem of molluscan phylogeny. The neuroanatomy of scaphopods demonstrates a highly derived architecture that shares a number of key characters with the cephalopod nervous system, and supports a Scaphopoda + Cephalopoda grouping.

  19. Bacterial diversity of siliciclastic sediments in a Thalassia testudinum meadow and the implications for Lucinisca nassula chemosymbiosis

    NASA Astrophysics Data System (ADS)

    Green-García, Angela M.; Engel, Annette Summers

    2012-10-01

    Despite the ecological and economic importance of Thalassia testudinum (turtle grass) meadows along the Caribbean and Gulf of Mexico coasts, and recognition that microbial activities are critical to plant growth and health, the bacterial diversity of these habitats has been poorly studied. Based on comparative analyses of 16S rRNA gene sequences from sediments in a T. testudinum meadow, 25 major taxonomic groups (excluding candidate divisions) were retrieved, including Alpha- Delta-, and Gamma-proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, Spirochaetes, and Firmicutes. The distribution of bacterial groups was linked to a strongly hypoxic and sulfidic redox gradient. The diversity is potentially novel because phylogenetic affinities of sediment sequences compared to contextually annotated environmental clones from different habitats or to cultured representatives indicated approximately 41% were more closely related to each other than to sequences retrieved from these other habitats. Of all the relationships, very few (2.4%) were to cultured organisms, but 27% were to environmental clones retrieved from shallow marine shelf and coastal sediments or from mangroves, estuarine, or wetland sediments. Rare sequences were closely related to endosymbiont groups of Lucinisca nassula (Lucinidea: Bivalvia) hosts collected from the same meadow, which may indicate that the sediment is a potential reservoir for free-living symbionts. This study provides insight into the ecological and evolutionary relationships of the Thalassia-lucinid-bacteria system in tropical to sub-tropical regions.

  20. Coastal Macroinvertebrate Study in Penang Island, Malaysia

    PubMed Central

    Yin, Chee Su; Kwang, Sim Yee

    2016-01-01

    Land reclamation in Penang began two decades ago and is still rampant with large reclamation projects planned to be executed in the near future. The present study provides the first information on effects of land reclamation in Penang towards the coastal macroinvertebrates. This study assessed the abundance, diversity, and evenness of coastal invertebrates assumed to be the foremost affected when land is reclaimed. Three kinds of areas were focused on: reclaimed, unclaimed (adjacent to reclaimed), and undisturbed. A total of 53 species of macroinvertebrates from 10 classes (Gastropoda, Bivalvia, Polychaeta, Malacostraca, Maxillopoda, Echinoidea, Polyplacophora, Branchiopoda, Scaphopoda, and Holothuroidea) were sampled. Reclaimed areas were moderately rich in species averaging 11 species compared to 7 species in adjacent and 14 in undisturbed areas. Species richness was the highest in Teluk Aling (an undisturbed area) with 22 species, and was the lowest in Gurney Drive (an adjacent area) with 2 species. The average species diversity and evenness on reclaimed land was the lowest with values of 1.9974 and 0.5787, respectively. The diversity was higher by 5.07% in adjacent areas and by 22.92% in undisturbed areas compared to reclaimed areas. Species evenness was 29.75% higher in unreclaimed areas and 17.87% higher in undisturbed areas compared to reclaimed areas. Land reclamation reduces species diversity and evenness, and to a lesser extent, species richness. PMID:27965739

  1. [Paralytic shellfish poisoning by Spondylus calcifer contaminated with Pyrodinium bahamense, Costa Rica, 1989-1990].

    PubMed

    Mata, L; Abarca, G; Marranghello, L; Víquez, R

    1990-06-01

    This paper describes an outbreak of paralytic shellfish poisoning (PSP), affecting human populations on the Pacific Coast of Costa Rica in October 1989. Numbness in arms, face and legs occurred 30 to 45 minutes after ingestion of the large clam Spondylus calcifer. Paralysis of legs and respiratory symptoms followed, often persisting for one week. Large amounts of the dinoflagellate Pyrodinium bahamense were found in the intestine of the mollusk. A toxin was detected in crude or filtered and heated macerates of intestine, muscle, mantle and hepatopancreas of S. calcifer, and to a lesser extent Tagelus sp., by injection of its crude or diluted extracts in white mice. The effects in mice consisted in paralysis and asphyxia generally leading to death in less than 5 minutes, compatible with saxitoxin. Mice were killed by the toxin in macerates diluted 1:100 to 1:1000. No toxin was detected in Anadara tuberculosa (Bivalvia) or in peneids. Prevention rests on intersectoral actions between state and private sectors in charge of fishing, distribution and marketing of shellfish, as well as on education of the population at large.

  2. Comparative analysis of riverscape genetic structure in rare, threatened and common freshwater mussels

    USGS Publications Warehouse

    Galbraith, Heather S.; Zanatta, David T; Wilson, Chris C.

    2015-01-01

    Freshwater mussels (Bivalvia: Unionoida) are highly imperiled with many species on the verge of local extirpation or global extinction. This study investigates patterns of genetic structure and diversity in six species of freshwater mussels in the central Great Lakes region of Ontario, Canada. These species vary in their conservation status (endangered to not considered at risk), life history strategy, and dispersal capabilities. Evidence of historical genetic connectivity within rivers was ubiquitous across species and may reflect dispersal abilities of host fish. There was little to no signature of recent disturbance events or bottlenecks, even in endangered species, likely as a function of mussel longevity and historical population sizes (i.e., insufficient time for genetic drift to be detectable). Genetic structure was largely at the watershed scale suggesting that population augmentation via translocation within rivers may be a useful conservation tool if needed, while minimizing genetic risks to recipient sites. Recent interest in population augmentation via translocation and propagation may rely on these results to inform management of unionids in the Great Lakes region.

  3. Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin.

    PubMed

    Bell, James B; Aquilina, Alfred; Woulds, Clare; Glover, Adrian G; Little, Crispin T S; Reid, William D K; Hepburn, Laura E; Newton, Jason; Mills, Rachel A

    2016-09-01

    Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250 m depth and report data from a series of geochemical and biological analyses. Here, the geochemical signatures were consistent with weak methane seepage and the role of sub-surface methane consumption was clearly very important, preventing gas emissions into bottom waters. As a result, the contribution of methane-derived carbon to the microbial and metazoan food webs was very limited, although sulfur isotopic signatures indicated a wider range of dietary contributions than was apparent from carbon isotope ratios. Macrofaunal assemblages had high dominance and were indicative of reducing sediments, with many taxa common to other similar environments and no seep-endemic fauna, indicating transitional assemblages. Also similar to other cold seep areas, there were samples of authigenic carbonate, but rather than occurring as pavements or sedimentary concretions, these carbonates were restricted to patches on the shells of Axinulus antarcticus (Bivalvia, Thyasiridae), which is suggestive of microbe-metazoan interactions.

  4. Complete genome sequence of Candidatus Ruthia magnifica.

    PubMed

    Roeselers, Guus; Newton, Irene L G; Woyke, Tanja; Auchtung, Thomas A; Dilly, Geoffrey F; Dutton, Rachel J; Fisher, Meredith C; Fontanez, Kristina M; Lau, Evan; Stewart, Frank J; Richardson, Paul M; Barry, Kerrie W; Saunders, Elizabeth; Detter, John C; Wu, Dongying; Eisen, Jonathan A; Cavanaugh, Colleen M

    2010-10-27

    The hydrothermal vent clam Calyptogena magnifica (Bivalvia: Mollusca) is a member of the Vesicomyidae. Species within this family form symbioses with chemosynthetic Gammaproteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a rudimentary gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. The C. magnifica symbiont, Candidatus Ruthia magnifica, was the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced (Newton et al. 2007). Here we expand upon the original report and provide additional details complying with the emerging MIGS/MIMS standards. The complete genome exposed the genetic blueprint of the metabolic capabilities of the symbiont. Genes which were predicted to encode the proteins required for all the metabolic pathways typical of free-living chemoautotrophs were detected in the symbiont genome. These include major pathways including carbon fixation, sulfur oxidation, nitrogen assimilation, as well as amino acid and cofactor/vitamin biosynthesis. This genome sequence is invaluable in the study of these enigmatic associations and provides insights into the origin and evolution of autotrophic endosymbiosis.

  5. Effects of human trampling on a rocky shore fauna on the Sao Paulo coast, southeastern Brazil.

    PubMed

    Ferreira, M N; Rosso, S

    2009-11-01

    Increased tourist activity in coastal regions demands management strategies to reduce impacts on rocky shores. The highly populated coastal areas in southeastern Brazil are an example of degradation caused by development of industry and tourism. Among different shore impacts, trampling has been intensively studied, and may represent a significant source of stress for intertidal fauna. A randomised blocks design was applied to experimentally study the effects of two different trampling intensities on richness, diversity, density and biomass of the rocky shore fauna of Obuseiro beach, Guarujá, southeastern Brazil. Blocks were distributed in two portions of the intertidal zone, dominated respectively by Chthamalus bisinuatus (Cirripedia) and Isognomon bicolor (Bivalvia). Blocks were trampled over three months, simulating the vacation period in Brazil and were monitored for the following nine months. Results indicate that Chthamalus bisinuatus is vulnerable to trampling impacts. Richness, diversity and turn-over index tended to be higher in trampled plots four months after trampling ceased. In general, results agree with previous trampling studies, suggesting that even low intensities of trampling may cause some impact on intertidal communities. Management strategies should include isolation of sensitive areas, construction of boardwalks, visitor education and monitoring programmes. In Brazil, additional data obtained from experimental studies are necessary in order to achieve a better understanding of trampling impacts on rocky shore communities.

  6. Composition and abundance of epibenthic-sledge catches in the South Polar Front of the Atlantic

    NASA Astrophysics Data System (ADS)

    Brandt, A.; Havermans, C.; Janussen, D.; Jörger, K. M.; Meyer-Löbbecke, A.; Schnurr, S.; Schüller, M.; Schwabe, E.; Brandão, S. N.; Würzberg, L.

    2014-10-01

    An epibenthic sledge (EBS) was deployed at seven different deep-sea stations along the South Polar Front of the Atlantic in order to explore the composition and abundance of macrofaunal organisms and to identify the most abundant taxa in this transition zone to the Southern Ocean. In total 3,130 specimens were sampled by means of the EBS on board of RV Polarstern during the expedition ANT-XXVIII/3 in the austral summer of 2012. Benthic and suprabenthic Crustacea occurred to be most frequent in the samples. Among those, copepods were by far most numerous, with 1,585 specimens followed by the peracarid taxa Isopoda (236 ind.), Amphipoda (103 ind.), Tanaidacea (78 ind.) and Cumacea (50 ind.). Annelida were represented by a high number of specimens belonging to different polychaete taxa (404 ind.). The molluscan fauna was clearly dominated by Bivalvia (255 ind.), followed in numbers of specimens by Gastropoda (47 ind.). The deep-sea benthos sampled along the Southern Polar Front occurred in surprisingly low abundances, contrasting the largely high surface productivity of the area. Numbers of specimens across different macrofaunal taxa and especially of peracarid crustaceans underscored by far those from South Ocean sites at higher latitudes in the Weddell Sea.

  7. The Abundance and Spatial Distribution of Soft Sediment Communities in Tanjung Bungah, Malaysia: A Preliminary Study

    PubMed Central

    Darif, Nur Aqilah Muhamad; Samad, Nur Shakila Abdul; Salleh, Sazlina; Mohammad, Mahadi; Nordin, Noor Alia Ahmad; Javeed, Aysha Mariam Mohamed; Jonik, Michelle Glory G; Zainudin, Muhamad Hilal Mohd

    2016-01-01

    Benthic faunal communities are important components in the intertidal zones. The diversity and abundance of the benthic communities are subjected to different natural and anthropogenic disturbances. The study was conducted as one off sampling on 6th November 2013 (1) to investigate the abundance and distribution of soft sediment communities in relation to environmental variables and (2) investigate the changes of population structure and diversity using spatial scales of 1 m, 10 m, and 100 m. Results indicated a total of 110 individuals of macrobenthos consisting of 7 different groups (Annelida, Bivalvia, Crustacea, Gastropoda, Nematoda, Nemertea, Polychaeta) and 4 different groups of meiobenthos (Copepoda, Nematoda, Ostracoda, Polychaeta) consisting 920 individuals were recorded. Dissolved oxygen played the most significant role in affecting the distribution of soft sediment communities while ammonia concentrations only affected marcobenthic organisms. However, sediment grain size did not show significant correlation (p>0.05) on soft sediment communities. Hence, understanding how different properties of benthos respond to changes in environmental variables is crucial in determining how the impacts on the sediment are tolerated by the benthic organisms. PMID:27965743

  8. Highly diverse molluscan assemblages of Posidonia oceanica meadows in northwestern Alboran Sea (W Mediterranean): Seasonal dynamics and environmental drivers

    NASA Astrophysics Data System (ADS)

    Urra, Javier; Mateo Ramírez, Ángel; Marina, Pablo; Salas, Carmen; Gofas, Serge; Rueda, José L.

    2013-01-01

    The seasonal dynamics of the molluscan fauna associated with the westernmost populations of the Mediterranean seagrass Posidonia oceanica, has been studied throughout an annual cycle in the northwestern coasts of the Alboran Sea. Samples were collected seasonally (5 replicated per season) using a non-destructive sampling technique (airlift sampler) on quadrats of 50 × 50 cm at 2 sites located 7 km apart. Several environmental variables from the water column (temperature, chlorophyll a), the sediment (percentage of organic matter) and the seagrass meadows (shoot density, leaf height and width, number of leaves per shoot) were also measured in order to elucidate their relationships with the dynamics of the molluscan assemblages. In these meadows, a total of 17,416 individuals of molluscs were collected, belonging to 71 families and 171 species, being Rissoidae, Pyramidellidae and Trochidae the best-represented families, and Mytilidae, Nassaridae and Trochidae the dominant ones in terms of abundance. The assemblages were dominated by micro-algal grazers, filter feeders and ectoparasites (including those feeding on sessile preys). The species richness and the abundance displayed significant maximum values in summer, whereas evenness and diversity displayed maximum values in spring, being significant for the evenness. Both abundance and species richness values were positively correlated to seawater temperature and percentage organic matter, only for the latter, and negatively to leaf width. Significant seasonal groupings were obtained with multivariate analyses (MDS, Cluster, ANOSIM) using qualitative and quantitative data that could be mainly related to biological aspects (i.e. recruitment) of single species. The molluscan assemblages are influenced by the biogeographical location of the area (Alboran Sea), reflected in the absence or scarcity of most Mediterranean species strictly associated with P. oceanica (e.g. Tricolia speciosa, Rissoa ventricosa) and by the

  9. A multi-proxy approach to identifying short-lived marine incursions in the Early Carboniferous

    NASA Astrophysics Data System (ADS)

    Bennett, Carys; Davies, Sarah; Leng, Melanie; Snelling, Andrea; Millward, David; Kearsey, Timothy; Marshall, John; Reves, Emma

    2015-04-01

    This study is a contribution to the TW:eed Project (Tetrapod World: early evolution and diversification), which examines the rebuilding of Carboniferous ecosystems following a mass extinction at the end of the Devonian. The project focuses on the Tournaisian Ballagan Formation of Scotland and the Borders, which contains rare fish and tetrapod material. The Ballagan Formation is characterised by sandstones, dolomitic cementstones, paleosols, siltstones and gypsum deposits. The depositional environment ranges from fluvial, alluvial-plain to marginal-marine environments, with fluvial, floodplain and lacustrine deposition dominant. A multi-proxy approach combining sedimentology, palaeontology, micropalaeontology, palynology and geochemistry is used to identify short-lived marine transgressions onto the floodplain environment. Rare marginal marine fossils are: Chondrites-Phycosiphon, Spirorbis, Serpula, certain ostracod species, rare orthocones, brachiopods and putative marine sharks. More common non-marine fauna include Leiocopida and Podocopida ostracods, Mytilida and Myalinida bivalves, plants, eurypterids, gastropods and fish. Thin carbonate-bearing dolomitic cementstones and siltstone contain are the sedimentary deposits of marine incursions and occur throughout the formation. Over 600 bulk carbon isotope samples were taken from the 500 metre thick Norham Core (located near Berwick-Upon-Tweed), encompassing a time interval of around 13 million years. The results range from -26o to -19 δ13Corg, with an average of -19o much lighter than the average value for Early Carboniferous marine bulk organic matter (δ13C of -28 to -30). The isotope results correspond to broad-scale changes in the depositional setting, with more positive δ13C in pedogenic sediments and more negative δ13C in un-altered grey siltstones. They may also relate to cryptic (short-lived) marine incursions. A comparison of δ13C values from specific plant/wood fragments, palynology and bulk

  10. Leaf anatomy and its implications for phylogenetic relationships in Taxaceae s. l.

    PubMed

    Ghimire, Balkrishna; Lee, Chunghee; Heo, Kweon

    2014-05-01

    The comparative study on leaf anatomy and stomata structures of six genera of Taxaceae s. l. was conducted. Leaf anatomical structures were very comparable to each other in tissue shape and their arrangements. Taxus, Austrotaxus, and Pseudotaxus have no foliar resin canal, whereas Amentotaxus, Cephalotaxus, and Torreya have a single resin canal located below the vascular bundle. Among them, Torreya was unique with thick-walled, almost round sclerenchymatous epidermal cells. In addition, Amentotaxus and Torreya were comprised of some fiber cells around the vascular bundle. Also, Amentotaxus resembled Cephalotaxus harringtonia and its var. nana because they have discontinuous fibrous hypodermis. However, C. fortunei lacked the same kind of cells. Stomata were arranged in two stomatal bands separated by a mid-vein. The most unique stomatal structure was of Taxus with papillose accessory cells forming stomatal apparatus and of Torreya with deeply seated stomata covered with a special filament structure. Some morphological and molecular studies have already been discussed for the alternative classification of taxad genera into different minor families. The present study is also similar to these hypotheses because each genus has their own individuality in anatomical structure and stomata morphology. In conclusion, these differences in leaf and stomata morphology neither strongly support the two tribes in Taxaceae nor fairly recognize the monogeneric family, Cephalotaxaceae. Rather, it might support an alternative classification of taxad genera in different minor families or a single family Taxaceae including Cephalotaxus. In this study, we would prefer the latter one because there is no clear reason to separate Cephalotaxus from the rest genera of Taxaceae. Therefore, Taxaceae should be redefined with broad circumscriptions including Cephalotaxus.

  11. Davallia bilabiata inhibits TNF-α-induced adhesion molecules and chemokines by suppressing IKK/NF-kappa B pathway in vascular endothelial cells.

    PubMed

    Yang, Rong-Chi; Chang, Cheng-Chieh; Sheen, Jer-Ming; Wu, Hsiao-Ting; Pang, Jong-Hwei S; Huang, Sheng-Teng

    2014-01-01

    Davallia bilabiata (D. bilabiata) is also called GuSuiBu in Taiwan and is used as a substitute for Drynaria fortunei J. Sm. It is often used for trauma and bone repair. The inhibitory effect of D. bilabiata on inflammatory activity has not been reported. In the present study, we aimed to study the mechanism of anti-inflammation of D. bilabiata on the adhesion of leukocytes to vascular endothelial cells. The results showed that D. bilabiata, at concentrations without cytotoxic effect, inhibited the adhesion of monocytes (THP-1) to the TNF-α-stimulated human umbilical vascular endothelial cells (HUVECs). D. bilabiata suppressed the expression of the adhesion molecules ICAM, VCAM, and E-selectin at both the mRNA and protein level. In addition, both of the TNF-α-induced mRNA and protein expression of chemokines including fractalkine/CX3CL1, MCP-1 and RANTES as well as the level of secreted soluble fractalkine were decreased by D. bilabiata. We also verified that D. bilabiata inhibited the TNF-α-induced nuclear translocation of NF-κB through the inhibitory process on the TNF-α-activated phosphorylation of IKKα, IKKβ, IκB and NF-κB. All together, we concluded that the D. bilabiata affected the canonical pathway of TNF-α-induced NF-κB activation and down-regulated cell adhesion molecules and chemokine expression through inhibition of the NF-κB/IκBα/IKK signaling pathway. These findings strongly indicated that D. bilabiata might be a promising alternative/adjunct treatment for inflammatory diseases, such as rheumatoid arthritis and osteoarthritis.

  12. [Biomass allometric equations of nine common tree species in an evergreen broadleaved forest of subtropical China].

    PubMed

    Zuo, Shu-di; Ren, Yin; Weng, Xian; Ding, Hong-feng; Luo, Yun-jian

    2015-02-01

    Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the species-specific and generalized BAEs using biomass measurement for 9 common broadleaved trees (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in species-specific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total tree than a combined variable (D2 H) of D and H (tree height) , but D2H was better than D in estimating stem biomass. R2 (coefficient of determination) values of BAEs for 6 species decreased when adding H as the second independent variable into D- only BAEs, where R2 value for S. sinensis decreased by 5.6%. Compared with generalized D- and D2H-based BAEs, standard errors of estimate (SEE) of BAEs for 8 tree species decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by tree species and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in tree species and model types.

  13. Antioxidant and anti-inflammatory activities of selected medicinal plants containing phenolic and flavonoid compounds.

    PubMed

    Zhang, Lin; Ravipati, Anjaneya S; Koyyalamudi, Sundar Rao; Jeong, Sang Chul; Reddy, Narsimha; Smith, Paul T; Bartlett, John; Shanmugam, Kirubakaran; Münch, Gerald; Wu, Ming Jie

    2011-12-14

    The antioxidant, anti-inflammatory, and cytotoxic activities of water and ethanol extracts of 14 Chinese medicinal plants were investigated and also their total phenolics and flavonoid contents measured. The antioxidant activity was evaluated in a biological assay using Saccharomyces cerevisiae , whereas the radical scavenging activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Total phenolics and flavonoid contents were estimated by Folin-Ciocalteu and aluminum chloride methods, respectively. The anti-inflammatory activities of the plant extracts were determined by measuring the inhibition of production of nitric oxide (NO) and TNF-α in LPS and IFN-γ activated RAW 264.7 macrophages. Their cytotoxic activities against macrophages were determined by Alamar Blue assay. Four plants, namely, Scutellaria baicalensis , Taxillus chinensis , Rheum officinale , and Sophora japonica , showed significant antioxidant activity in both yeast model and also free radical scavenging methods. The ethanol extract of S. japonica showed highest levels of phenolics and flavonoids (91.33 GAE mg/g and 151.86 QE mg/g, respectively). A positive linear correlation between antioxidant activity and the total phenolics and flavonoid contents indicates that these compounds are likely to be the main antioxidants contributing to the observed activities. Five plant extracts (S. baicalensis, T. chinensis, S. japonica, Mahonia fortunei , and Sophora flavescens ) exhibited significant anti-inflammatory activity by in vitro inhibition of the production of NO and TNF-α with low IC(50) values. These findings suggest that some of the medicinal herbs studied in this paper are good sources of antioxidants.

  14. Cell-Wall Changes and Cell Tension in Response to Cold Acclimation and Exogenous Abscisic Acid in Leaves and Cell Cultures.

    PubMed Central

    Rajashekar, C. B.; Lafta, A.

    1996-01-01

    Freeze-induced cell tensions were determined by cell water relations in leaves of broadleaf evergreen species and cell cultures of grapes (Vitis spp.) and apple (Malus domestica). Cell tensions increased in response to cold acclimation in leaves of broadleaf evergreen species during extracellular freezing, indicating a higher resistance to cell volume changes during freezing in cold-hardened leaves than in unhardened leaves. Unhardened leaves, typically, did not develop tension greater than 3.67 MPa, whereas cold-hardened leaves attained tensions up to 12 MPa. With further freezing there was a rapid decline and a loss of tension in unhardened leaves of all the broadleaf evergreen species studied. Also, similar results were observed in cold-hardened leaves of all of the species except in those of inkberry (Ilex glabra) and Euonymus fortunei, in which negative pressures persisted below -40[deg]C. Abscisic acid treatment of inkberry and Euonymus kiautschovica resulted in increases in freeze-induced tensions in leaves, suggesting that both cold acclimation and abscisic acid have similar effects on freezing behavior[mdash] specifically on the ability of cell walls to undergo deformation. Decreases in peak tensions were generally associated with lethal freezing injury and may suggest cavitation of cellular water. However, in suspension-cultured cells of grapes and apple, no cell tension was observed during freezing. Cold acclimation of these cells resulted in an increase in the cell-wall strength and a decrease in the limiting cell-wall pore size from 35 to 22 A in grape cells and from 29 to 22 A in apple cells. PMID:12226314

  15. Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

    PubMed

    Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-04-01

    We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil.

  16. Dietary habits of invasive Ponto-Caspian gobies in the Croatian part of the Danube River basin and their potential impact on benthic fish communities.

    PubMed

    Piria, Marina; Jakšić, Goran; Jakovlić, Ivan; Treer, Tomislav

    2016-01-01

    Invasive Ponto-Caspian (P-C(1)) gobies have recently caused dramatic changes in fish assemblage structures throughout the Danube basin. While their presence in the Croatian part of the basin has been noted and distribution studied, their dietary habits and impacts on native fish communities have, until now, been unknown. In 2011, 17 locations in the Sava River Basin were sampled for fish and 15 for benthic invertebrates. Fish population monitoring data, available for nine seasons (2003-2006 and 2010-2014) and 12 locations, were used to analyse the impacts of P-C gobies on benthic fish abundance. Gut content analysis indicates that the monkey goby Neogobius fluviatilis diet is very diverse, but dominated by Trichoptera, Chironomidae, Bivalvia and Odonata. The diet overlaps considerably with the round goby Neogobius melanostomus diet, although Gastropoda are dominant in the latter's diet. Small fish and Gammarus sp. dominate the bighead goby Ponticola kessleri diet. Comparison of gut content with the prey available in the environment indicates that monkey and round gobies exhibit preference for Trichoptera, Megaloptera and Coleoptera, and bighead goby for Trichoptera, Gammarus sp. and Pisces. P-C gobies in the Sava River are spreading upstream, towards the reaches with lower fish diversity. Analyses indicate potentially positive impacts of P-C gobies' presence on some fish populations: round and bighead goby on Balkan golden loach Sabanejewia balcanica and monkey goby on common carp Cyprinus carpio, crucian carp Carassius carassius, burbot Lota lota and Balkan loach Cobitis elongata. However, there are also indications that bighead and round goby could adversely impact the native chub Squalius cephalus and zingel Zingel zingel populations, respectively. As P-C gobies are still in the expansionary period of invasion and the ecosystem still adapting to new circumstances, continued monitoring of fish population dynamics in the Sava basin is needed to determine the

  17. Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment.

    PubMed

    Pratt, Daniel R; Lohrer, Andrew M; Thrush, Simon F; Hewitt, Judi E; Townsend, Michael; Cartner, Katie; Pilditch, Conrad A; Harris, Rachel J; van Colen, Carl; Rodil, Iván F

    2015-01-01

    Identifying the effects of stressors before they impact ecosystem functioning can be challenging in dynamic, heterogeneous 'real-world' ecosystems. In aquatic systems, for example, reductions in water clarity can limit the light available for photosynthesis, with knock-on consequences for secondary consumers, though in naturally turbid wave-swept estuaries, detecting the effects of elevated turbidity can be difficult. The objective of this study was to investigate the effects of shading on ecosystem functions mediated by sandflat primary producers (microphytobenthos) and deep-dwelling surface-feeding macrofauna (Macomona liliana; Bivalvia, Veneroida, Tellinidae). Shade cloths (which reduced incident light intensity by ~80%) were deployed on an exposed, intertidal sandflat to experimentally stress the microphytobenthic community associated with the sediment surface. After 13 weeks, sediment properties, macrofauna and fluxes of oxygen and inorganic nutrients across the sediment-water interface were measured. A multivariate metric of ecosystem function (MF) was generated by combining flux-based response variables, and distance-based linear models were used to determine shifts in the drivers of ecosystem function between non-shaded and shaded plots. No significant differences in MF or in the constituent ecosystem function variables were detected between the shaded and non-shaded plots. However, shading reduced the total explained variation in MF (from 64% in non-shaded plots to 15% in shaded plots) and affected the relative influence of M. liliana and other explanatory variables on MF. This suggests that although shade stress may shift the drivers of ecosystem functioning (consistent with earlier investigations of shading effects on sandflat interaction networks), ecosystem functions appear to have a degree of resilience to those changes.

  18. Immune responses to infectious diseases in bivalves.

    PubMed

    Allam, Bassem; Raftos, David

    2015-10-01

    Many species of bivalve mollusks (phylum Mollusca, class Bivalvia) are important in fisheries and aquaculture, whilst others are critical to ecosystem structure and function. These crucial roles mean that considerable attention has been paid to the immune responses of bivalves such as oysters, clams and mussels against infectious diseases that can threaten the viability of entire populations. As with many invertebrates, bivalves have a comprehensive repertoire of immune cells, genes and proteins. Hemocytes represent the backbone of the bivalve immune system. However, it is clear that mucosal tissues at the interface with the environment also play a critical role in host defense. Bivalve immune cells express a range of pattern recognition receptors and are highly responsive to the recognition of microbe-associated molecular patterns. Their responses to infection include chemotaxis, phagolysosomal activity, encapsulation, complex intracellular signaling and transcriptional activity, apoptosis, and the induction of anti-viral states. Bivalves also express a range of inducible extracellular recognition and effector proteins, such as lectins, peptidoglycan-recognition proteins, thioester bearing proteins, lipopolysaccharide and β1,3-glucan-binding proteins, fibrinogen-related proteins (FREPs) and antimicrobial proteins. The identification of FREPs and other highly diversified gene families in bivalves leaves open the possibility that some of their responses to infection may involve a high degree of pathogen specificity and immune priming. The current review article provides a comprehensive, but not exhaustive, description of these factors and how they are regulated by infectious agents. It concludes that one of the remaining challenges is to use new "omics" technologies to understand how this diverse array of factors is integrated and controlled during infection.

  19. Richness, systematics, and distribution of molluscs associated with the macroalga Gigartina skottsbergii in the Strait of Magellan, Chile: A biogeographic affinity study

    PubMed Central

    Rosenfeld, Sebastián; Aldea, Cristian; Mansilla, Andrés; Marambio, Johanna; Ojeda, Jaime

    2015-01-01

    Abstract Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m2 were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities. PMID:26448707

  20. Phylogeny, phylogeography, and evolution in the Mediterranean region: News from a freshwater mussel (Potomida, Unionida).

    PubMed

    Froufe, Elsa; Prié, Vincent; Faria, João; Ghamizi, Mohamed; Gonçalves, Duarte V; Gürlek, Mustafa Emre; Karaouzas, Ioannis; Kebapçi, Ümit; Şereflişan, Hülya; Sobral, Carina; Sousa, Ronaldo; Teixeira, Amílcar; Varandas, Simone; Zogaris, Stamatis; Lopes-Lima, Manuel

    2016-07-01

    The Potomida genus (Bivalvia, Unionida) has a Circum-Mediterranean distribution and like other freshwater mussel species, its populations have suffered dramatic declines. Although this genus is currently considered as monotypic, it has a long history of taxonomic revisions and presently many aspects of its systematics and evolutionary history are unclear. We sampled a total of 323 individuals from 39 different sites across the Potomida genus distribution, and sequenced two mitochondrial (16S rDNA and Cytochrome c Oxidase Subunit I) and one nuclear (28S rDNA) genes to clarify its phylogeny and phylogeographic history. Our results show that the genus includes two well-supported clades, one comprising solely the western Mediterranean species Potomida littoralis, and the other including two eastern Mediterranean species, the Greek endemic P. acarnanica and the Anatolian and Middle Eastern P. semirugata. We suggest that Potomida started radiating during the upper Miocene, and that both vicariance and dispersal events shaped the diversification and distribution of the genus along the Mediterranean region. P. littoralis is further divided in two mitochondrial lineages, one restricted to Europe and the other occurring mostly in North Africa. Moreover, some European basins present both lineages in sympatry. The conservation status of the three recognized species should be reevaluated, particularly P. acarnanica, since it is restricted to two Greek river basins presenting a high risk of extinction. Overall, our results clarify some important gaps in knowledge concerning the phylogeny, phylogeography and evolution of the Potomida genus in the Mediterranean region with important taxonomical, ecological and conservational implications.

  1. MetaSINEs: Broad Distribution of a Novel SINE Superfamily in Animals

    PubMed Central

    Nishihara, Hidenori; Plazzi, Federico; Passamonti, Marco; Okada, Norihiro

    2016-01-01

    SINEs (short interspersed elements) are transposable elements that typically originate independently in each taxonomic clade (order/family). However, some SINE families share a highly similar central sequence and are thus categorized as a SINE superfamily. Although only four SINE superfamilies (CORE-SINEs, V-SINEs, DeuSINEs, and Ceph-SINEs) have been reported so far, it is expected that new SINE superfamilies would be discovered by deep exploration of new SINEs in metazoan genomes. Here we describe 15 SINEs, among which 13 are novel, that have a similar 66-bp central region and therefore constitute a new SINE superfamily, MetaSINEs. MetaSINEs are distributed from fish to cnidarians, suggesting their common evolutionary origin at least 640 Ma. Because the 3′ tails of MetaSINEs are variable, these SINEs most likely survived by changing their partner long interspersed elements for retrotransposition during evolution. Furthermore, we examined the presence of members of other SINE superfamilies in bivalve genomes and characterized eight new SINEs belonging to the CORE-SINEs, V-SINEs, and DeuSINEs, in addition to the MetaSINEs. The broad distribution of bivalve SINEs suggests that at least three SINEs originated in the common ancestor of Bivalvia. Our comparative analysis of the central domains of the SINEs revealed that, in each superfamily, only a restricted region is shared among all of its members. Because the functions of the central domains of the SINE superfamilies remain unknown, such structural information of SINE superfamilies will be useful for future experimental and comparative analyses to reveal why they have been retained in metazoan genomes during evolution. PMID:26872770

  2. Evolutionary implications of endosymbiont diversity within lucinid bivalves

    NASA Astrophysics Data System (ADS)

    Garcia, A. M.; Thiessen, M.; Aronowsky, A.; Anderson, L.; Bao, H.; Engel, A.

    2007-12-01

    Bacterial endosymbiosis is widespread among Bivalvia. Symbiosis between lucinid bivalves and sulfur-oxidizing (thiotrophic) bacteria has received recent attention, as lucinids are one of the geologically oldest extant bivalve clades to possess endosymbionts. However, the ecological and evolutionary relationships between host and symbiont are poorly understood, and reconstructing the evolutionary history and geological significance of lucinid endosymbiosis requires additional knowledge and characterization of endosymbiont ecology and taxonomic diversity. Our goal was to characterize the bacterial diversity of a modern lucinid habitat in order to evaluate possible lucinid endosymbiont diversity. Host organisms ( Lucinisca nassula and Phacoides pectinatus) and sediment cores were collected from geochemically reducing and sulfide-rich sea grass beds. PCR amplification and sequencing of bacterial 16S rRNA genes from the sediment cores retrieved 13 major taxonomic groups, including equally dominant Chloroflexi, Delta-, and Gammaproteobacteria, and rare Bacteroides, Acidobacteria, Spirochaetes, and Firmicutes. Less than 2% of the sequences were affiliated with uncultured gammaproteobacterial symbiont groups, but were not closely related to the sequences retrieved from the lucinid gills. Moreover, our analyses uncovered multiple gene sequence populations within an individual, as well as across individuals within the same sampling site. Additional habitat-host-symbiont diversity from three other lucinid taxa and from six geographically distinct habitat sites is also expanding the previously understood diversity of thiotrophic endosymbionts, and specifically that the lucinid symbionts are probably not a monophyletic species. These data suggest that thiotrophic bacteria are recruitable for endosymbiosis and are widely distributed in reducing marine environments. But, because of the diversity of bacteria in any one habitat, symbionts may be metabolically and physiologically

  3. Gastropod arginine kinases from Cellana grata and Aplysia kurodai. Isolation and cDNA-derived amino acid sequences.

    PubMed

    Suzuki, T; Inoue, N; Higashi, T; Mizobuchi, R; Sugimura, N; Yokouchi, K; Furukohri, T

    2000-12-01

    Arginine kinase (AK) was isolated from the radular muscle of the gastropod molluscs Cellana grata (subclass Prosobranchia) and Aplysia kurodai (subclass Opisthobranchia), respectively, by ammonium sulfate fractionation, Sephadex G-75 gel filtration and DEAE-ion exchange chromatography. The denatured relative molecular mass values were estimated to be 40 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isolated enzyme from Aplysia gave a Km value of 0.6 mM for arginine and a Vmax value of 13 micromole Pi min(-1) mg protein(-1) for the forward reaction. These values are comparable to other molluscan AKs. The cDNAs encoding Cellana and Aplysia AKs were amplified by polymerase chain reaction, and the nucleotide sequences of 1,608 and 1,239 bp, respectively, were determined. The open reading frame for Cellana AK is 1044 nucleotides in length and encodes a protein with 347 amino acid residues, and that for A. kurodai is 1077 nucleotides and 354 residues. The cDNA-derived amino acid sequences were validated by chemical sequencing of internal lysyl endopeptidase peptides. The amino acid sequences of Cellana and Aplysia AKs showed the highest percent identity (66-73%) with those of the abalone Nordotis and turbanshell Battilus belonging to the same class Gastropoda. These AK sequences still have a strong homology (63-71%) with that of the chiton Liolophura (class Polyplacophora), which is believed to be one of the most primitive molluscs. On the other hand, these AK sequences are less homologous (55-57%) with that of the clam Pseudocardium (class Bivalvia), suggesting that the biological position of the class Polyplacophora should be reconsidered.

  4. Compound-Specific Amino Acid Isotopic Analysis of Benthic Food Webs in the Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Cooper, L. W.; Biasatti, D. M.; Grebmeier, J. M.

    2014-12-01

    The Chukchi Sea is known for locally high standing stocks of benthic macrofauna and strong coupling between pelagic-benthic components of the ecosystem. However, benthic food structure is not fully understood, due to varied sources of particulate organic matter (POM) and the high diversity of benthic invertebrates. We provide the first demonstration of the application of compound-specific amino acid isotope analysis to study the dietary sources and trophic structure for this Arctic marginal sea. About 20 stations in Chukchi Sea were sampled during cruises in August of 2012 and 2013. At each station, phytoplankton, POM and benthic fauna were collected, processed and analyzed using GC-C-IRMS (gas chromatography-combustion-isotope ratio mass spectrometry). Among benthic fauna, dominant species included the following taxonomic groups: Ophiuroidea, Amphipoda, Polychaeta, Gastropoda, Bivalvia, and Cnidaria. The benthic fauna showed similar patterns of individual amino acid δ13C, with glycine the most enriched in 13C and leucine the most depleted in 13C. Specific amino acids including phenylalanine showed spatial variability in δ13C and δ15N values within the sampled area, indicating contributions of different dietary sources including phytoplankton, sea ice algae, benthic algae and terrestrial organic materials. δ15N values of individual amino acids such as the difference between glutamic acid and phenylalanine, i.e. Δ15Nglu-phe (δ15Nglu - δ15Nphe), were also used to identify trophic levels of benthic invertebrates relative to estimates available from bulk δ15N values. These data will ultimately be used to evaluate the spatial variability of organic carbon sources and trophic level interactions of dominant benthic species in the Chukchi Sea.

  5. In vivo sulfhydryl distribution in brown cells of Mercenaria mercenaria exposed to cadmium

    SciTech Connect

    Zaroogian, G.

    1995-12-31

    Brown cells are found in the red glands of Mercenaria mercenaria (Bivalvia) and have a role in detoxification. Brown cell involvement in metal detoxification is due in part to endogenous glutathione (GSH) and protein bound sulfhydryl (PBSH). During treatment of Mercenaria with 0.5 and 1.0 ppm Cd{sup 2+}, brown cells were analyzed for total sulfhydryl (TSH), PBSH, non-protein bound sulfhydryl (NPSH) and GSH after 0.25, 1, 2, 3, 6, 12 and 20 days. Trend analyses indicated that treatment with 0.5 ppm Cd{sup 2+} caused a continuous increase in PBSH/TSH, whereas NPSH/TSH did not appear to change during 20 days treatment. The GSH/NPSH ratio increased significantly (P<0.01) for 6 days, followed by a significant (P<0.01) continuous decrease to day 20. Treatment with 1.0 ppm Cd{sup 2+} caused an increase in NPSH/TSH during the first 3 days, after which the ratio remained fairly constant to day 20, whereas PBSH/TSH decreased today 2, increased to day 3 and remained unchanged to day 20. The GSH/NPSH ratio remained fairly constant for the first 12 days after which it increased significantly (P<0.01). Histopathological examination after treatment with 1.0 ppm Cd 2{sup +} indicated darkening of the lysosomes during the first 2 days, followed by extensive brown cell sloughing into the tubule lumen and the abundance of small lysosomes at day 3. Sloughing and small lysosome formation continued to a lesser extent to day 20 when granulocyte infiltration and necrosis of the intertubular connective tissue occurred. The data indicate that GSH is more resistant to fluctuations than PBSH which suggests a more rapid synthesis or turnover rate for GSH. The ratio of GSH to PBSH has potential for a biomarker of cadmium exposure and health of Mercenaria.

  6. Quantification of diagenetic overprint processes deduced from fossil carbonate shells and laboratory-based hydrothermal alteration experiments

    NASA Astrophysics Data System (ADS)

    Griesshaber, Erika; Casella, Laura; Mavromatis, Vasileios; Dietzel, Martin; Immenhauser, Adrian; Schmahl, Wolfgang

    2016-04-01

    Benthic and nektonic marine biogenic carbonate archives represent the foundation of numerous studies aiming at reconstructions of past climate dynamics and environmental change. However, living organisms are not in thermodynamic equilibrium and create local chemical environments where physiologic processes such as biomineralization takes place. After the death of the organism the former physiologic disequilibrium conditions are not sustained any more and all biological tissues are altered by equilibration according to the surrounding environment: diagenesis. With increasing diagenetic alteration, the biogenic structure and fingerprint fades away and is replaced by inorganic features. Thus, recrystallization of organism-specific microstructure is a clear indicator for diagenetic overprint. Microstructural data, which mirror recrystallization, are of great value for interpreting geochemical proxies for paleo-environment reconstruction. Despite more than a century of research dealing with carbonate diagenesis, many of the controlling processes and factors are only understood in a qualitative manner. One of the main issues is that diagenetically altered carbonates are usually present as the product of a complex preceding diagenetic pathway with an unknown number of intermediate steps. In this contribution we present and discuss laboratory based alteration experiments with the aim to investigate time-series data sets in a controlled manner. We conducted hydrothermal alteration experiments with modern Arctica islandica (bivalvia) and Notosaria nigricans (brachiopoda) in order to mimic diagenetic overprint. We explore first the potential of electron backscattered diffraction (EBSD) measurements together with statistical data evaluation as a tool to quantify diagenetic alteration of carbonate skeletons. Subsequently, we compare microstructural patterns obtained from experimentally altered shell material with those of fossil specimens that have undergone variable degrees of

  7. Confocal Raman microscopy in sclerochronology: A powerful tool to visualize environmental information in recent and fossil biogenic archives

    NASA Astrophysics Data System (ADS)

    Beierlein, Lars; Nehrke, Gernot; Brey, Thomas

    2015-01-01

    hard parts and skeletons of aquatic organisms often archive information of past environmental conditions. Deciphering such information forms an essential contribution to our understanding of past climate conditions and thus our ability to mitigate the climatic, ecological, and social impacts of a rapidly changing environment. Several established techniques enable the visualization and reliable use of the information stored in anatomical features of such biogenic archives, i.e., its growth patterns. Here, we test whether confocal Raman microscopy (CRM) is a suitable method to reliably identify growth patterns in the commonly used archive Arctica islandica and the extinct species Pygocardia rustica (both Bivalvia). A modern A. islandica specimen from Norway has been investigated to verify the general feasibility of CRM, resulting in highly correlated standardized growth indices (r > 0.96 p < 0.0001) between CRM-derived measurements and measurements derived from the established methods of fluorescence microscopy and Mutvei's solution staining. This demonstrates the general suitability of CRM as a method for growth pattern evaluation and cross-dating applications. Moreover, CRM may be of particular interest for paleoenvironmental reconstructions, as it yielded superior results in the analysis of fossil shell specimens (A. islandica and P. rustica) compared to both Mutvei staining and fluorescence microscopy. CRM is a reliable and valuable tool to visualize internal growth patterns in both modern and fossil calcium carbonate shells that notably also facilitates the assessment of possible diagenetic alteration prior to geochemical analysis without geochemically compromising the sample. We strongly recommend the CRM approach for the visualization of growth patterns in fossil biogenic archives, where conventional methods fail to produce useful results.

  8. Wetland macroinvertebrates of Prentiss Bay, Lake Huron, Michigan: diversity and functional group composition

    USGS Publications Warehouse

    Merritt, R.W.; Benbow, M.E.; Hudson, P.L.

    2002-01-01

    The Great Lakes support many fish and waterbirds that depend directly or indirectly on coastal wetlands during some portion of their life cycle. It is known that macroinvertebrates make up an important part of wetland food webs and ecosystem function; however, our understanding of species distribution within and among wetlands has only recently received attention. We investigated the macroinvertebrates of a freshwater marsh (Prentiss Bay) in the Les Chenaux Island Area of Northern Lake Huron, Michigan. Macroinvertebrate taxa diversity and functional feeding group composition were compared between two habitats. A shallow depositional habitat with higher vegetation diversity and little wave action was compared to a deeper erosional habitat with fewer plant species and more wave action. A total of 83 taxa were collected over the summer of 1996, representing two phyla (Arthropoda and Mollusca) and five classes (Arachnida, Bivalvia, Malacostraca, Gastropoda and Insecta). A total of 79 genera were identified, with 92% being insects (39 families composed of at least 73 genera). Of the total, 42 insect genera were common to both habitats,while relatively fewer were collected exclusively from the erosional compared the depositional habitat. When habitats were pooled, predators comprised about 50% of the functional group taxa, while gathering collectors and shredders each were about 20%. Filtering collectors and scrapers each represented < 10%. When comparing habitats, there was a relatively higher percentage of predators and shredders in the depositional habitat, while all other functional groups were lower. These data suggest that vegetation diversity, depth and wave action affect taxa composition and functional group organization of the Prentiss Bay marsh.

  9. The Purisima Formation at Capitola Beach, Santa Cruz County, CA: A Deeper Examination of Pliocene Fossils

    NASA Astrophysics Data System (ADS)

    White, L. D.; Brooks, K.; Chen, R.; Chen, T.; James, T.; Gonzales, J.; Schumaker, D.; Williams, D.

    2005-12-01

    Fossil samples from the Pliocene Purisima Formation at Capitola Beach in Santa Cruz County, CA were collected in July-August 2005. The Purisima Formation composes the bulk of the cliffs exposed at Capitola Beach and a rich assemblage of well-preserved fossils occur in gray to brown sandstone and siltstone. Erosion of the cliff face averages 0.3 meter/year and fresh cliff falls in the winter and spring months of 2005 provided an excellent opportunity to resample the Capitola Beach section of the Purisima Formation previously documented by Perry (1988). Organisms were identified from information in Perry (1988) and were compared with collections at the California Academy of Sciences. The most abundant fossils found are from the phylum Mollusca, classes Bivalvia and Gastropoda. Abundant bivalve taxa are: Anadara trilineata, Clinocardium meekianum, Macoma sp., Protothaca staleyi, and Tresus pajaroanus. Also common are the gastropods, Calyptraea fastigata, Crepdiula princeps, Mitrella gausapata, Nassarius grammatus, Nassarius californianus, Natica clausa, and Olivella pedroana. Less common invertebrate fossils are from the phylum Echinodermata ( Dendraster sp., the extinct fossil sand dollar) and from the phylum Arthropoda ( Crustacea), crab fragments ( Cancer) and barnacles ( Balanus). Because numerous fossils are concentrated as fragments in shell beds, Norris (1986) and Perry (1988) believe many were redeposited as storm beds during strong current events that promoted rapid burial. In contrast, whale and other vertebrate bones are common in certain horizons and their presence may be related to the conditions that promoted phosphate mineralization, such as episodes of low sedimentation rates and prolonged exposure on the seafloor (Föllmi and Garrison, 1991). The bone beds, together with the rich infaunal and epifaunal invertebrate assemblages, represent a community of invertebrate organisms that thrived in a shallow marine sea during the Pliocene epoch, approximately

  10. Investigation of Li/Ca variations in aragonitic shells of the ocean quahog Arctica islandica, northeast Iceland

    NASA Astrophysics Data System (ADS)

    ThéBault, Julien; SchöNe, Bernd R.; Hallmann, Nadine; Barth, Matthias; Nunn, Elizabeth V.

    2009-12-01

    Interannual and intra-annual variations in lithium-to-calcium ratio were investigated with high temporal resolution in the aragonitic outer shell layer of juvenile Arctica islandica (Mollusca; Bivalvia) collected alive in 2006 off northeast Iceland. Li/Cashell ranged between 7.00 and 11.12 μmol mol-1 and presented well-marked seasonal cycles with minimum values recorded at the annual growth lines; a general pattern was a progressive increase in Li/Cashell from March to May, followed by a plateau in June and a decrease down to minimum values in July-August. Li/Cashell was correlated with δ18Oshell-derived temperature, but the strength of this relationship was weak (r2 < 0.25 and p < 0.05). It covaried significantly with microgrowth increment width and with the discharge from one of the closest rivers. Seasonal variations of Li/Cashell in A. islandica may most likely be explained (1) by calcification rate and/or (2) by significant river inputs of Li-rich silicate particles flowing to the sea as soon as snow melts. In the first case, Li/Cashell may be a useful proxy for addressing seasonal variations of growth rate in bivalves that lack discernable microgrowth patterns. Abrupt decreases of Li/Cashell may, in turn, help identify growth retardations due to harsh environmental conditions. Alternatively, if Li/Cashell variations are linked to particulate Li inputs by rivers, this could be a new proxy for the intensity of mechanical weathering of Icelandic basalts, with interesting perspectives for the reconstruction of frequency and intensity of past jökulhlaups (subglacial outburst floods). Further works, including experimental studies, are needed to test these hypotheses.

  11. Environmental heterogeneity predicts species richness of freshwater mollusks in sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Hauffe, T.; Schultheiß, R.; Van Bocxlaer, B.; Prömmel, K.; Albrecht, C.

    2016-09-01

    Species diversity and how it is structured on a continental scale is influenced by stochastic, ecological, and evolutionary driving forces, but hypotheses on determining factors have been mainly examined for terrestrial and marine organisms. The extant diversity of African freshwater mollusks is in general well assessed to facilitate conservation strategies and because of the medical importance of several taxa as intermediate hosts for tropical parasites. This historical accumulation of knowledge has, however, not resulted in substantial macroecological studies on the spatial distribution of freshwater mollusks. Here, we use continental distribution data and a recently developed method of random and cohesive allocation of species distribution ranges to test the relative importance of various factors in shaping species richness of Bivalvia and Gastropoda. We show that the mid-domain effect, that is, a hump-shaped richness gradient in a geographically bounded system despite the absence of environmental gradients, plays a minor role in determining species richness of freshwater mollusks in sub-Saharan Africa. The western branch of the East African Rift System was included as dispersal barrier in richness models, but these simulation results did not fit observed diversity patterns significantly better than models where this effect was not included, which suggests that the rift has played a more complex role in generating diversity patterns. Present-day precipitation and temperature explain richness patterns better than Eemian climatic condition. Therefore, the availability of water and energy for primary productivity during the past does not influence current species richness patterns much, and observed diversity patterns appear to be in equilibrium with contemporary climate. The availability of surface waters was the best predictor of bivalve and gastropod richness. Our data indicate that habitat diversity causes the observed species-area relationship, and hence, that

  12. Temporal changes in the geographic distribution of two clam species Meretrix lusoria and M. petechialis along the coast of Japan and South Korea

    NASA Astrophysics Data System (ADS)

    Sato, Shin'ichi; Kaneko, Yoshitaka; Torii, Hiroshi; Hong, Jae-Sang

    2016-09-01

    The objectives of this study were to distinguish fossil specimens of Meretrix (Bivalvia, Veneridae) using discriminant score and multivariate analysis, and to examine temporal changes in the geographical distributions of M. lusoria and M. petechialis in Japan and South Korea. Fossil shells of Meretrix were collected from Miyagi, Fukui, Aichi and Kumamoto in Japan, and Gimhae, Seosan, Siheung and Ganghwa-do in South Korea. The outside of the right valve was photographed with a digital camera, and ten characteristics of the shell morphology, such as shell height and shell length, were measured using image analysis software and a digital slide caliper. The discriminant score and multivariate analysis of the shell morphology identified all of the examined fossils as M. lusoria, while living individuals collected from the western coast of South Korea were identified as M. petechialis. These results suggest that the fossil shells excavated from the western coast of South Korea are a different species from the living individuals collected from the same areas. Radioactive carbon isotopic results revealed that the ages of the four fossil shells collected from tidal flats in Ganghwa-do ranged between 3,270 ± 30 and 1,830 ± 30 Cal BP. These results suggest that M. lusoria inhabited the western coast of South Korea until at least 2,000 years ago, but was replaced by M. petechialis during the last 2,000 years. Therefore, we propose that either M. petechialis spats were introduced artificially, or planktonic larvae migrated naturally from China to the western coast of South Korea during the last 2,000 years.

  13. Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment

    PubMed Central

    Pratt, Daniel R.; Lohrer, Andrew M.; Thrush, Simon F.; Hewitt, Judi E.; Townsend, Michael; Cartner, Katie; Pilditch, Conrad A.; Harris, Rachel J.; van Colen, Carl; Rodil, Iván F.

    2015-01-01

    Identifying the effects of stressors before they impact ecosystem functioning can be challenging in dynamic, heterogeneous ‘real-world’ ecosystems. In aquatic systems, for example, reductions in water clarity can limit the light available for photosynthesis, with knock-on consequences for secondary consumers, though in naturally turbid wave-swept estuaries, detecting the effects of elevated turbidity can be difficult. The objective of this study was to investigate the effects of shading on ecosystem functions mediated by sandflat primary producers (microphytobenthos) and deep-dwelling surface-feeding macrofauna (Macomona liliana; Bivalvia, Veneroida, Tellinidae). Shade cloths (which reduced incident light intensity by ~80%) were deployed on an exposed, intertidal sandflat to experimentally stress the microphytobenthic community associated with the sediment surface. After 13 weeks, sediment properties, macrofauna and fluxes of oxygen and inorganic nutrients across the sediment-water interface were measured. A multivariate metric of ecosystem function (MF) was generated by combining flux-based response variables, and distance-based linear models were used to determine shifts in the drivers of ecosystem function between non-shaded and shaded plots. No significant differences in MF or in the constituent ecosystem function variables were detected between the shaded and non-shaded plots. However, shading reduced the total explained variation in MF (from 64% in non-shaded plots to 15% in shaded plots) and affected the relative influence of M. liliana and other explanatory variables on MF. This suggests that although shade stress may shift the drivers of ecosystem functioning (consistent with earlier investigations of shading effects on sandflat interaction networks), ecosystem functions appear to have a degree of resilience to those changes. PMID:26214854

  14. Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves.

    PubMed

    Pila, E A; Sullivan, J T; Wu, X Z; Fang, J; Rudko, S P; Gordy, M A; Hanington, P C

    2016-05-01

    Haematopoiesis is a process that is responsible for generating sufficient numbers of blood cells in the circulation and in tissues. It is central to maintenance of homeostasis within an animal, and is critical for defense against infection. While haematopoiesis is common to all animals possessing a circulatory system, the specific mechanisms and ultimate products of haematopoietic events vary greatly. Our understanding of this process in non-vertebrate organisms is primarily derived from those species that serve as developmental and immunological models, with sparse investigations having been carried out in other organisms spanning the metazoa. As research into the regulation of immune and blood cell development advances, we have begun to gain insight into haematopoietic events in a wider array of animals, including the molluscs. What began in the early 1900's as observational studies on the morphological characteristics of circulating immune cells has now advanced to mechanistic investigations of the cytokines, growth factors, receptors, signalling pathways, and patterns of gene expression that regulate molluscan haemocyte development. Emerging is a picture of an incredible diversity of developmental processes and outcomes that parallels the biological diversity observed within the different classes of the phylum Mollusca. However, our understanding of haematopoiesis in molluscs stems primarily from the three most-studied classes, the Gastropoda, Cephalopoda and Bivalvia. While these represent perhaps the molluscs of greatest economic and medical importance, the fact that our information is limited to only 3 of the 9 extant classes in the phylum highlights the need for further investigation in this area. In this review, we summarize the existing literature that defines haematopoiesis and its products in gastropods, cephalopods and bivalves.

  15. Richness, systematics, and distribution of molluscs associated with the macroalga Gigartina skottsbergii in the Strait of Magellan, Chile: A biogeographic affinity study.

    PubMed

    Rosenfeld, Sebastián; Aldea, Cristian; Mansilla, Andrés; Marambio, Johanna; Ojeda, Jaime

    2015-01-01

    Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m(2) were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities.

  16. Temporal and spatial distribution of the meiobenthic community in Daya Bay, South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, L.; Li, H. X.; Yan, Y.

    2012-04-01

    Spatial and temporal biodiversity patterns of the meiobenthos were studied for the first time in Daya Bay, which is a tropical semi-enclosed basin located in the South China Sea. The abundance, biomass, and composition of the meiobenthos and the basic environmental factors in the bay were investigated. The following 19 taxonomic groups were represented in the meiofauna: Nematoda, Copepoda, Polychaeta, Oligochaeta, Kinorhyncha, Gastrotricha, Ostracoda, Bivalvia, Turbellaria, Nemertinea, Sipuncula, Hydroida, Amphipoda, Cumacea, Halacaroidea, Priapulida, Echinodermata, Tanaidacea, and Rotifera. Total abundance and biomass of the meiobenthos showed great spatial and temporal variation, with mean values of 993.57 ± 455.36 ind cm-2 and 690.51 ± 210.64 μg 10 cm-2, respectively. Nematodes constituted 95.60 % of the total abundance and thus had the greatest effect on meiofauna quantity and distribution, followed by copepods (1.55 %) and polychaetes (1.39 %). Meiobenthos abundance was significantly negatively correlated with water depth at stations (r=-0.747, P<0.05) and significantly negatively correlated with silt-clay content (r=-0.516, P<0.01) and medium diameter (r=-0.499, P<0.01) of the sediment. Similar results were found for correlations of biomass and abundance of nematodes with environmental parameters. Polychaete abundance was positively correlated with the bottom water temperature (r=0.456, P<0.01). Meiobenthos abundance differed significantly among seasons (P<0.05), although no significant difference among stations and the interaction of station × season was detected by two-way ANOVA. In terms of vertical distribution, most of the meiobenthos was found in the surface layer of sediment. This pattern was apparent for nematodes and copepods, but a vertical distribution pattern for polychaetes was not as obvious. Based on the biotic indices and analyses of their correlations and variance, the diversity of this community was likely to be influenced by

  17. Radiological impact of TEPCO's Fukushima Dai-ichi Nuclear Power Plant accident on invertebrates in the coastal benthic food web.

    PubMed

    Sohtome, Tadahiro; Wada, Toshihiro; Mizuno, Takuji; Nemoto, Yoshiharu; Igarashi, Satoshi; Nishimune, Atsushi; Aono, Tatsuo; Ito, Yukari; Kanda, Jota; Ishimaru, Takashi

    2014-12-01

    Radioactive cesium ((134)Cs and (137)Cs) concentrations in invertebrates of benthic food web (10 taxonomic classes with 46 identified families) collected from wide areas off Fukushima Prefecture (3-500 m depth) were inspected from July 2011, four months after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, to August 2013 to elucidate time-series trends among taxa and areas. Cesium-137 was detected in seven classes (77% of 592 specimens). Higher (137)Cs concentrations within detected data were often found in areas near or south of the FDNPP, which is consistent with the reported spatial distribution of (137)Cs concentrations in highly contaminated seawater and sediments after the FDNPP accident. Overall (137)Cs concentrations in invertebrates, the maxima of which (290 Bq kg(-1)-wet in the sea urchin Glyptocidaris crenularis) were lower than in many demersal fishes, had decreased exponentially with time, and exhibited taxon-specific decreasing trends. Concentrations in Bivalvia and Gastropoda decreased clearly with respective ecological half-lives of 188 d and 102 d. In contrast, decreasing trends in Malacostraca and Polychaeta were more gradual, with longer respective ecological half-lives of 208 d and 487 d. Echinoidea showed no consistent trend, presumably because of effects of contaminated sediments taken into their digestive tract. Comparison of (137)Cs concentrations in the invertebrates and those in seawater and sediments suggest that contaminated sediments are the major source of continuing contamination in benthic invertebrates, especially in Malacostraca and Polychaeta.

  18. Resolving the evolutionary relationships of molluscs with phylogenomic tools.

    PubMed

    Smith, Stephen A; Wilson, Nerida G; Goetz, Freya E; Feehery, Caitlin; Andrade, Sónia C S; Rouse, Greg W; Giribet, Gonzalo; Dunn, Casey W

    2011-10-26

    Molluscs (snails, octopuses, clams and their relatives) have a great disparity of body plans and, among the animals, only arthropods surpass them in species number. This diversity has made Mollusca one of the best-studied groups of animals, yet their evolutionary relationships remain poorly resolved. Open questions have important implications for the origin of Mollusca and for morphological evolution within the group. These questions include whether the shell-less, vermiform aplacophoran molluscs diverged before the origin of the shelled molluscs (Conchifera) or lost their shells secondarily. Monoplacophorans were not included in molecular studies until recently, when it was proposed that they constitute a clade named Serialia together with Polyplacophora (chitons), reflecting the serial repetition of body organs in both groups. Attempts to understand the early evolution of molluscs become even more complex when considering the large diversity of Cambrian fossils. These can have multiple dorsal shell plates and sclerites or can be shell-less but with a typical molluscan radula and serially repeated gills. To better resolve the relationships among molluscs, we generated transcriptome data for 15 species that, in combination with existing data, represent for the first time all major molluscan groups. We analysed multiple data sets containing up to 216,402 sites and 1,185 gene regions using multiple models and methods. Our results support the clade Aculifera, containing the three molluscan groups with spicules but without true shells, and they support the monophyly of Conchifera. Monoplacophora is not the sister group to other Conchifera but to Cephalopoda. Strong support is found for a clade that comprises Scaphopoda (tusk shells), Gastropoda and Bivalvia, with most analyses placing Scaphopoda and Gastropoda as sister groups. This well-resolved tree will constitute a framework for further studies of mollusc evolution, development and anatomy.

  19. Identification of Male Gametogenesis Expressed Genes from the Scallop Nodipecten subnodosus by Suppressive Subtraction Hybridization and Pyrosequencing

    PubMed Central

    Llera-Herrera, Raúl; García-Gasca, Alejandra; Abreu-Goodger, Cei; Huvet, Arnaud; Ibarra, Ana M.

    2013-01-01

    Despite the great advances in sequencing technologies, genomic and transcriptomic information for marine non-model species with ecological, evolutionary, and economical interest is still scarce. In this work we aimed to identify genes expressed during spermatogenesis in the functional hermaphrodite scallop Nodipecten subnodosus (Mollusca: Bivalvia: Pectinidae), with the purpose of obtaining a panel of genes that would allow for the study of differentially transcribed genes between diploid and triploid scallops in the context of meiotic arrest and reproductive sterility. Because our aim was to isolate genes involved in meiosis and other testis maturation-related processes, we generated suppressive subtractive hybridization libraries of testis vs. inactive gonad. We obtained 352 and 177 ESTs by clone sequencing, and using pyrosequencing (454-Roche) we maximized the identified ESTs to 34,276 reads. A total of 1,153 genes from the testis library had a blastx hit and GO annotation, including genes specific for meiosis, spermatogenesis, sex-differentiation, and transposable elements. Some of the identified meiosis genes function in chromosome pairing (scp2, scp3), recombination and DNA repair (dmc1, rad51, ccnb1ip1/hei10), and meiotic checkpoints (rad1, hormad1, dtl/cdt2). Gene expression analyses in different gametogenic stages in both sexual regions of the gonad of meiosis genes confirmed that the expression was specific or increased towards the maturing testis. Spermatogenesis genes included known testis-specific ones (kelch-10, shippo1, adad1), with some of these known to be associated to sterility. Sex differentiation genes included one of the most conserved genes at the bottom of the sex-determination cascade (dmrt1). Transcript from transposable elements, reverse transcriptase, and transposases in this library evidenced that transposition is an active process during spermatogenesis in N. subnodosus. In relation to the inactive library, we identified 833

  20. Nontargeted metabolomics reveals biochemical pathways altered in response to captivity and food limitation in the freshwater mussel Amblema plicata.

    PubMed

    Roznere, Ieva; Watters, G Thomas; Wolfe, Barbara A; Daly, Marymegan

    2014-12-01

    Effective conservation of freshwater mussels (Mollusca: Bivalvia: Unionidae), one of the most endangered groups of animals in North America, is compromised by limited knowledge of their health. We address this gap in knowledge by characterizing the metabolic profile of Amblema plicata in the wild and in response to captivity and food limitation. Eight mussels brought into captivity from the wild were isolated for 18 days without a food source. Hemolymph samples were taken prior to, and 9 and 18 days after the start of the experiment; these samples were analyzed by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. We detected and identified 71 biochemicals in the hemolymph of freshwater mussels; of these, 49 showed significant changes during captivity and/or food limitation (p<0.05). Fasting resulted in severe metabolite depletion. Captive (but fed) mussels experienced changes similar to (albeit less severe than) fasting mussels, suggesting that mussels may experience nutritional deficiency under common captive conditions. A. plicata responded to food limitation stress by preferentially using energy reserves for maintenance rather than growth. Carbohydrate and energy metabolism exhibited down-regulation in captive, food-limited, and wild mussels. Lipid metabolism was up-regulated in captive/food-limited mussels and unchanged in wild mussels. Amino acid metabolism was up-regulated in wild mussels and down-regulated in captive/food-limited mussels. Nucleotide metabolism was up-regulated in the wild mussels, down-regulated in food-limited mussels, and unchanged in captive mussels. The different responses between treatment groups suggest potential for nucleotide metabolism as a biomarker of health status for freshwater mussels.

  1. Molecular systematics of the critically-endangered North American spinymussels (Unionidae: Elliptio and Pleurobema) and description of Parvaspina gen. nov.

    USGS Publications Warehouse

    Perkins, Michael A.; Johnson, Nathan A.; Gangloff, Michael M.

    2017-01-01

    Despite being common in numerous marine bivalve lineages, lateral spines are extremely rare among freshwater bivalves (Bivalvia: Unionidae), with only three known species characterized by the presence of spines: Elliptio spinosa, Elliptio steinstansana, and Pleurobema collina. All three taxa are endemic to the Atlantic Slope of southeastern North America, critically endangered, and protected by the US Endangered Species Act. Currently, these species are recognized in two genera and remain a source of considerable taxonomic confusion. Because spines are rare in freshwater mussels and restricted to a small region of North America, we hypothesized that spinymussels represent a monophyletic group. We sequenced two mtDNA gene fragments (COI and ND1) and a fragment of the nuclear ITS-1 locus from >70 specimens. Bayesian and maximum-likelihood phylogenetic reconstructions suggest that the spinymussels do not comprise a monophyletic group. Elliptio steinstansana is sister to P. collina, forming a monophyletic clade that was estimated to have diverged from its most recent ancestor in the late Miocene and is distinct from both Elliptio and Pleurobema; we describe a new genus (Parvaspina gen. nov.) to reflect this relationship. Additionally, E. spinosa forms a monophyletic clade that diverged from members of the core Elliptio lineage in the mid-Pliocene. Furthermore, E. spinosa is genetically divergent from the other spinymussel species, suggesting that spines, while extremely rare in freshwater mussels worldwide, may have evolved independently in two bivalve lineages. Recognizing the genetic distinctiveness and inter-generic relationships of the spinymussels is an important first step towards effectively managing these imperiled species and lays the groundwork for future conservation genetics studies.

  2. [Abundance and biomass of meiobenthos in Lingdingyang Bay of Pearl River Estuary].

    PubMed

    Zhang, Jing-huai; Gao, Yang; Fang, Hong-da

    2011-10-01

    An investigation was conducted on the meiobenthic abundance and biomass in the Lingdingyang Bay of Pearl River Estuary in July-August 2006 (summer), April 2007 (spring), and October 2007 (autumn). A total of 15 meiobenthic groups were recorded, including Nematoda, Copepoda, Polychaeta, Ostracoda, Kinorhyncha, Amphipoda, Cumacea, Tanaidacea, Gnathostomulida, Nemertea, Gastropoda, Bivalvia, Sipuncula, Echiura, and other unidentified taxa. The average abundance of the meiobenthos in spring, summer, and autumn was 272.1 +/- 281.9, 165.1 +/- 147.1 and 246. 4 +/- 369.3 ind 10 cm(-2), and Nematoda was the most dominant group in abundance, accounting for 86.8%, 83.5%, and 93.4% of the total, respectively, followed by Polychaeta, and benthic Copepoda. The meiobenthic abundance had an uneven vertical distribution. 54.1% of the meibenthos were in 0-2 cm sediments, 35.2% were in 2-5 cm sediments, and 10.8% were in 5-10 cm sediments. 87.4% of nematodes were distributed in 0-5 cm sediments. The average biomass of the meiobenthos in spring, summer, and autumn was 374.6 +/- 346.9, 274.1 +/- 352.2, and 270.8 +/- 396.0 microg 10 cm(-2), and Polychaeta was the most dominant group in biomass, accounting for 30.1%, 46.7% and 46.0%, respectively, followed by Nematoda (25.2%, 20.1%, and 34.0%), and Ostracoda (20.6%, 15.3%, and 14.8%). The horizontal distribution of the meiobenthos had a trend of increasing from north to south, and being higher at east than at west. The meiobenthic abundance and biomass had significant positive correlations with water depth.

  3. A molecular-based approach for examining responses of eukaryotes in microcosms to contaminant-spiked estuarine sediments.

    PubMed

    Chariton, Anthony A; Ho, Kay T; Proestou, Dina; Bik, Holly; Simpson, Stuart L; Portis, Lisa M; Cantwell, Mark G; Baguley, Jeffrey G; Burgess, Robert M; Pelletier, Marguerite M; Perron, Monique; Gunsch, Claudia; Matthews, Robin A

    2014-02-01

    Ecotoxicological information for most contaminants is limited to a small number of taxa, and these are generally restricted to comparatively hardy organisms that are readily extractable from test media and easily identifiable. Advances in DNA sequencing can now provide a comprehensive view of benthic invertebrate diversity. The authors applied 454 pyrosequencing to examine the responses of benthic communities in microcosms exposed to sediments with elevated concentrations of triclosan, the endpoint being eukaryl communities that have successfully vertically migrated through the manipulated sediments. The biological communities associated with the 3 treatments (control triclosan, low triclosan [14 mg/kg], and high triclosan [180 mg/kg]) clustered into 3 groups: control/low (n = 6 controls and 4 low), moderate (n = 2 low), and high (n = 5 high). One sample was discarded as an outlier. The most pronounced change as a response to triclosan was the loss of number of metazoan operational taxonomic units (OTUs), indicative of the control/low and moderate groups, with this being most evident in the range of taxa associated with the classes Chromadorea and Bivalvia and the phylum Kinorhyncha. The authors also describe a range of other taxa that aided discrimination between the groups; compare findings with traditionally obtained meio- and macrofaunal communities obtained from the same experiment; and illustrate some of the advantages and limitations associated with both the molecular and traditional approaches. The described approach illustrates the capacity for amplicon sequencing to provide ecologically relevant information that can be used to strengthen an understanding of how sedimentary communities respond to a range of environmental stressors.

  4. Epifauna of the Sea of Japan collected via a new epibenthic sledge equipped with camera and environmental sensor systems

    NASA Astrophysics Data System (ADS)

    Brandt, A.; Elsner, N.; Brenke, N.; Golovan, O.; Malyutina, M. V.; Riehl, T.; Schwabe, E.; Würzberg, L.

    2013-02-01

    Faunistic data from a newly designed camera-epibenthic sledge (C-EBS) are presented. These were collected during the joint Russian-German expedition SoJaBio (Sea of Japan Biodiversity Studies) on board the R.V. Akademik Lavrentyev from four transects (A-D) between 460 and 3660 m depth. In total, 244,531 macro- and megafaunal individuals were sampled with the classes Malacostraca (80,851 individuals), Polychaeta (36,253 ind.) and Ophiuroidea (34,004 ind.) being most abundant. Within the Malacostraca, Peracarida (75,716 ind.) were most abundant and within these, the Isopoda were the dominant taxon (27,931 ind.), followed by Amphipoda (21,403 ind.), Cumacea (13,971 ind.) and Tanaidacea (10,830 ind.). Mysidacea (1581 ind.) were least frequent. Bivalvia, Amphipoda, Cumacea and Mysidacea as well as inbenthic meiofaunal Nematoda occurred in higher numbers at the shallower stations and their numbers decreased with increasing depth. Polychaeta, Isopoda, and Tanaidacea, on the contrary, increased in abundance with increasing depth. Only one isopod species was sampled at abyssal depths in the Sea of Japan but at very high abundance: Eurycope spinifrons Gurjanova, 1933 (Asellota: Munnopsidae). Echinoderms occurred frequently at the shallower slope stations. Ophiuroids were dominating, followed by holothurians, and echinoids and asteroids which occurred in lower numbers and primarily at the shallower stations of transects A and B. Only 2163 individual anthozoans were recorded and these were mostly confined to the lower slope. The technical design of a new C-EBS is described. Next to temperature-insulated epi- and suprabenthic samplers, it is equipped with still and video cameras, which deliver information on seabed topography and megafaunal occurrence. Furthermore, Aanderaa CTD and SEAGUARD RCM allow for collection of physical parameters, such as near bottom oxygen composition, temperature and conductivity.

  5. Body Size Versus Depth: Regional and Taxonomical Variation in Deep-Sea Meio- and Macrofaunal Organisms.

    PubMed

    van der Grient, Jesse M A; Rogers, Alex D

    2015-01-01

    Body size (weight per individual) is an important concept in ecology. It has been studied in the deep sea where a decrease in size with increasing depth has often been found. This has been explained as an adaptation to food limitation where size reduction results in a lowered metabolic rate and a decreased energetic requirement. However, observations vary, with some studies showing an increase in size with depth, and some finding no depth correlation at all. Here, we collected data from peer-reviewed studies on macro- and meiofaunal abundance and biomass, creating two datasets allowing statistical comparison of factors expected to influence body size in meio- and macrofaunal organisms. Our analyses examined the influence of region, taxonomic group and sampling method on the body size of meiofauna and macrofauna in the deep sea with increasing depth, and the resulting models are presented. At the global scale, meio- and macrofaunal communities show a decrease in body size with increasing depth as expected with the food limitation hypothesis. However, at the regional scale there were differences in trends of body size with depth, either showing a decrease (e.g. southwest Pacific Ocean; meio- and macrofauna) or increase (e.g. Gulf of Mexico; meiofauna only) compared to a global mean. Taxonomic groups also showed differences in body size trends compared to total community average (e.g. Crustacea and Bivalvia). Care must be taken when conducting these studies, as our analyses indicated that sampling method exerts a significant influence on research results. It is possible that differences in physiology, lifestyle and life history characteristics result in different responses to an increase in depth and/or decrease in food availability. This will have implications in the future as food supply to the deep sea changes as a result of climate change (e.g. increased ocean stratification at low to mid latitudes and reduced sea ice duration at high latitudes).

  6. Next Generation Sequencing Reveals the Hidden Diversity of Zooplankton Assemblages

    PubMed Central

    Harmer, Rachel A.; Somerfield, Paul J.; Atkinson, Angus

    2013-01-01

    Background Zooplankton play an important role in our oceans, in biogeochemical cycling and providing a food source for commercially important fish larvae. However, difficulties in correctly identifying zooplankton hinder our understanding of their roles in marine ecosystem functioning, and can prevent detection of long term changes in their community structure. The advent of massively parallel next generation sequencing technology allows DNA sequence data to be recovered directly from whole community samples. Here we assess the ability of such sequencing to quantify richness and diversity of a mixed zooplankton assemblage from a productive time series site in the Western English Channel. Methodology/Principle Findings Plankton net hauls (200 µm) were taken at the Western Channel Observatory station L4 in September 2010 and January 2011. These samples were analysed by microscopy and metagenetic analysis of the 18S nuclear small subunit ribosomal RNA gene using the 454 pyrosequencing platform. Following quality control a total of 419,041 sequences were obtained for all samples. The sequences clustered into 205 operational taxonomic units using a 97% similarity cut-off. Allocation of taxonomy by comparison with the National Centre for Biotechnology Information database identified 135 OTUs to species level, 11 to genus level and 1 to order, <2.5% of sequences were classified as unknowns. By comparison a skilled microscopic analyst was able to routinely enumerate only 58 taxonomic groups. Conclusions Metagenetics reveals a previously hidden taxonomic richness, especially for Copepoda and hard-to-identify meroplankton such as Bivalvia, Gastropoda and Polychaeta. It also reveals rare species and parasites. We conclude that Next Generation Sequencing of 18S amplicons is a powerful tool for elucidating the true diversity and species richness of zooplankton communities. While this approach allows for broad diversity assessments of plankton it may become increasingly

  7. The Evolutionary Origins of the Southern Ocean Philobryid Bivalves: Hidden Biodiversity, Ancient Persistence

    PubMed Central

    Jackson, Jennifer A.; Linse, Katrin; Whittle, Rowan; Griffiths, Huw J.

    2015-01-01

    Philobryids (Bivalvia: Arcoida) are one of the most speciose marine bivalve families in the Southern Ocean and are common throughout the Southern Hemisphere. Considering this diversity and their brooding reproductive mode (limiting long-distance dispersal), this family may have been present in the Southern Ocean since its inception. However Philobrya and Adacnarca appear only in the Quaternary fossil record of the Antarctic, suggesting a much more recent incursion. Molecular dating provides an independent means of measuring the time of origin and radiation of this poorly known group. Here we present the first combined molecular and morphological investigation of the Philobryidae in the Southern Ocean. Two nuclear loci (18S and 28S) were amplified from 35 Southern Ocean Adacnarca and Philobrya specimens, with a combined sequence length of 2,282 base pairs (bp). Adacnarca specimens (A. nitens and A. limopsoides) were resolved as a strongly supported monophyletic group. Genus Philobrya fell into two strongly supported groups (‘sublaevis’ and ‘magellanica/wandelensis’), paraphyletic with Adacnarca. The A. nitens species complex is identified as at least seven morpho-species through morphological and genetic analysis of taxon clustering. Phylogenetic analyses resolve Philobryidae as a strongly supported monophyletic clade and sister taxon to the Limopsidae, as anticipated by their classification into the superfamily Limopsoidea. Bayesian relaxed clock analyses of divergence times suggest that genus Adacnarca radiated in the Southern Ocean from the Early Paleogene, while P. sublaevis and P. wandelensis clades radiated in the late Miocene, following the formation of the Antarctic Circumpolar Current. PMID:25853413

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

    PubMed

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

    2016-05-01

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

  9. The mineralogical responses of marine calcifiers to CO2-induced ocean acidification

    NASA Astrophysics Data System (ADS)

    Ries, J. B.; Cohen, A. L.; McCorkle, D. C.

    2008-12-01

    We have conducted 6-month laboratory experiments to investigate the effect of pCO2-induced reductions in seawater CaCO3 saturation state on biocalcification by 18 aragonitic and calcitic (low-high Mg) taxa representing eight of the major marine calcifying groups: Chlorophyta; Rhodophyta; Crustacea; Bivalvia; Gastropoda; Annelida; Cnidaria; and Echinodermata. The CaCO3 saturation states of the experimental seawaters, constrained by intercalibrated determinations of pH, alkalinity, and DIC, were attained with bubbled air-CO2 mixtures of 400 (ambient), 600, 900, and 2850 ppm pCO2, yielding Ωarag of 2.5 (ambient), 2.0, 1.5, 0.7, respectively. We previously showed that while rates of net calcification obtained from buoyant weighing declined with increasing pCO2 for nearly half of the species investigated, a nearly equal number exhibited constant or, in some cases, increased calcification under moderately (600 ppm) or extremely (900 or 2850 ppm) elevated pCO2. The organisms' investigated in this study secrete various forms of CaCO3, which differ in crystallographic structure and therefore solubility: aragonite and high-Mg are generally more soluble than low-Mg calcite. We have employed powder x-ray diffraction, Raman spectroscopy, inductively-coupled-plasma mass-spectrometry, and scanning electron microscopy to quantify changes in the organisms' skeletal mineralogy (aragonite:calcite ratio) and Mg-content (MgCO3:CaCO3 ratio) that occurred in response to the prescribed reductions in seawater CaCO3 saturation state. We will compare calcification and mineralogical response patterns amongst the organisms to elucidate the role of mineral lability in driving species-specific responses to CO2-induced ocean acidification.

  10. Strong pathways for incorporation of terrestrially derived organic matter into benthic communities

    NASA Astrophysics Data System (ADS)

    McLeod, Rebecca J.; Wing, Stephen R.

    2009-05-01

    In Fiordland, New Zealand, large volumes of organic matter are deposited into the marine environment from pristine forested catchments. Analyses of δ15N, δ13C and δ34S were employed to determine whether these inputs were contributing to marine food webs via assimilation by common macroinvertebrates inhabiting the inner reaches of the fjords. Terrestrially derived organic matter (TOM) had values of δ15N, δ13C and δ34S that were distinct from other carbon source pools, providing sufficient power to quantify the contribution of TOM to the benthic food web. Isotopic values among macroinvertebrates varied significantly, with consistently low values of δ15N, δ13C and δ34S for the abundant deposit feeders Echinocardium cordatum (Echinodermata) and Pectinaria australis (Annelida), indicating assimilation of TOM. High concentrations of bacterial fatty acid biomarkers in E. cordatum, and values of δ13C of these biomarkers similar to TOM (-27 to -30‰) confirmed that TOM is indirectly assimilated by these sea urchins via heterotrophic bacteria. TOM was also found to enter the infaunal food web via chemoautotrophic bacteria that live symbiotically within Solemya parkinsonii (Bivalvia). Echinocardium cordatum, Pectinaria australis and S. parkinsonii comprised up to 33.5% of the biomass of the macroinfaunal community, and thus represent strong pathways for movement of organic matter from the forested catchments into the benthic food web. This demonstration of connectivity among adjacent marine and terrestrial habitats has important implications for coastal land management, and highlights the importance of intact coastal forests to marine ecosystem function.

  11. Study on life parameters of the invasive species Octodonta nipae (Coleoptera: Chrysomelidae) on different palm species, under laboratory conditions.

    PubMed

    Hou, Youming; Miao, Yunxin; Zhang, Zhiyong

    2014-08-01

    In southeastern China, the invasion of the nipa palm hispid Octodonta nipae (Maulik) (Coleoptera: Chrysomelidae) results in devastating damage to palms. Host plants play an important role in the population increases and outbreaks of O. nipae. O. nipae could not complete its development on the Majestic palm (Ravenea rivularis Jumelle & Perrier), and females did not lay eggs on Chinese fan palm (Livistona chinensis R. Brown). However, this insect species both completed development and laid eggs on Chinese windmill palm (Trachycarpus fortunei (Hooker) H. Wendland), Canary Island date palm (Phoenix canariensis Chabaud), and pygmy date palm (Phoenix roebelenii O' Brien). The demographic characteristics of O. nipae reared on Chinese windmill palm, Canary Island date palm, and pygmy date palm were compared with an age-stage, two-sex life table. In this study, the developmental periods from egg to adult varied from 42.1 d on Chinese windmill palm to 49.8 d on pygmy date palm. The survivorship from egg to adult on Chinese windmill palm, Canary Island date palm, and pygmy date palm was 77.5, 79.4, and 66.7%, respectively. Although the adult longevity and the mean fecundity for individuals reared on Chinese windmill palm, Canary Island date palm, and pygmy date palm were not significantly different, there were significant differences in the intrinsic rate of increase, the finite rate, and the mean generation time among palm species, and the values of intrinsic rate of increase and finite rate were higher for populations reared on Chinese windmill palm and Canary Island date palm (0.0313 and 1.0318 d(-1) and 0.0278 and 1.0282 d(-1), respectively) and lower for populations reared on pygmy date palm (0.0192 and 1.0194 d(-1)). However, mean generation time was shorter on Chinese windmill palm (124.11 d) and Canary Island date palm (129.62 d) and longer on pygmy date palm (166.03 d). Our study indicated that different hosts affected life parameters of O. nipae, with the most

  12. Effect of sediment settling on controlling golden mussel invasion in water transfer project

    NASA Astrophysics Data System (ADS)

    Xu, Mengzhen; Wang, Zhaoyin; Bogen, Jim; Pan, Baozhu

    2013-04-01

    Inter-basin water transfer projects have been widely used to solve uneven distribution of water resources and water shortage in China. Along with the transferring of water resources, golden mussel (Limnoperna fortunei), the filter-collector macro-invertebrate species originating from southern China has also been inadvertently transferred to new aquatic environment, resulting in quick and uncontrolled spread of the species. The golden mussels are invasive by nature and endowed with a strong byssus for attaching onto their habitat, allowing them to easily invade natural and artificial aquatic systems, which was resulted in high-density golden mussel attachment that causes serious bio-fouling. Invasion and bio-fouling by golden mussels in water transfer systems has drawn attention widely because it has resulted in high resistance to water flow, corrosion of pipe walls and even clogging of tunnels, as well as causing water pollution and ecological imbalance in the regions that receive water infested with golden mussels. Field investigation was conducted along the East River, which is the main drinking water resource for Cantong province and Hongkong, China, to study the natural habitats of golden mussels. Surveys of water transfer tunnels which carry water from the East River to several big cities in Cantong province were done to study golden mussel invasion and attachment in tunnels. It is found that in the natural habitat, golden mussels mainly attach to bedrock and bank stones and solid surfaces facing upstream, while no golden mussels are attached on the surfaces facing downstream and suffering sediment deposition. In the water transfer tunnels, golden mussel attachment densities of 40,000 individuals/m2 mainly occurred on the portion of tunnel walls which face downwards and thus avoid sedimentation. An experiment was designed to study the effect of sediment settling on golden mussel attachment. The results showed that settling of fine sediment particles affects

  13. Carbon Sequestration Potential in Stands under the Grain for Green Program in Southwest China

    PubMed Central

    Chen, Xiangang; Luo, Yunjian; Zhou, Yongfeng; Lu, Mei

    2016-01-01

    The Grain for Green Program (GGP) is the largest afforestation and reforestation project in China in the early part of this century. To assess carbon sequestration i