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At least 577 records · Page 32Linked to original sources
PubMed2005

A beta-galactose-specific lectin isolated from the marine worm Chaetopterus variopedatus possesses anti-HIV-1 activity.

A 30 kDa beta-galactose-specific lectin named CVL was isolated from the polychaete marine worm Chaetopterus variopedatus (Annelida) and its anti-HIV-1 activity in vitro was determined. Results showed that CVL inhibited cytopathic effect induced by HIV-1 and the production of viral p24 antigen. The EC(50) values were 0.0043 and 0.057 microM, respectively. Time-of-addition analysis of anti-HIV-1 activity indicated its action was at the early stage of virus replication. CVL could blocked the cell-to-cell fusion process of HIV infected and uninfected cells with an EC(50) of 0.073 microM. The inhibition of HIV-1 entry into host cells was demonstrated by using fluorescence-based real-time quantify PCR. At CVL concentration of 0.33 microM and 0.07 microM, 86% and 21% virus attachment were blocked, respectively. The anti-HIV-1 action of CVL might relate to blockade of HIV-1 entry into cells.

Animals↗
PubMed2006

Tolerance and biomarkers as useful tools for assessing environmental quality in the Oued Souss estuary (Bay of Agadir, Morocco).

The aim of this study was to assess aquatic environmental quality of Oued Souss (Agadir, Morocco). This estuary has been subjected for a long time to large amounts of sewage discharges and industrial effluents. Since November 2002, no waste outlets have been discharged in this site due to their connection to a wastewater purification plant. Firstly, we have compared metal tolerance of the annelid polychaete (Nereis diversicolor) originating from Oued Souss and a relatively clean site (Oualidia, Morocco). Secondly, we have evaluated with a multi-marker approach (acetylcholinesterase [AChE], glutathione-S-transferases [GSTs], catalase, thiobarbituric acid reactive substances [TBARs]) responses of worms to the pollution gradient. Results have shown that worms from Oued Souss have acquired tolerance to copper and zinc due to a long-term sub-lethal metal exposure and this metal tolerance was maintained in spite of the end of wastewater discharges in this site. Higher catalase, GSTs and TBARs values have been observed in worms from Oued Souss sampled before implantation of wastewater treatment. The multi-marker approach confirms that these worms have been submitted to various contaminants. In contrast, high inhibition in AChE activities measured in worms from Oued Souss could be explained by the continuous agricultural influence of nearest areas. The level of contamination was probably maintained since biomarker values were generally higher in worms from Oued Souss when compared to Oualidia.

Adaptation, Physiological↗
PubMed2006

cDNA cloning and expression analysis of the catalytic subunit of glutamate cysteine ligase gene in an annelid polychaete after cadmium exposure: a potential tool for pollution biomonitoring.

The enzyme glutamate cysteine ligase (GCL) is the rate-limiting enzyme in glutathione (GSH) synthesis and is formed by a catalytic (GCLC) and a modulatory subunit (GCLM). Some studies have demonstrated that environmental pollutants can regulate the expression of these subunits. Despite the importance of these genes in toxicological responses, no sequences are available for the GCL subunits in annelids. The present study reports, for the first time, the cDNA sequence for the GCLC in an annelid species, the polychaete Laeonereis acuta (Nereididae). The deduced amino acid sequence of L. acuta GCLC showed homology with other animal species, and was used to infer a phylogenetic tree with GCLC amino acid sequences from other taxonomic groups. Exposure to cadmium (100 and 1000 microg Cd/L) during 14 days augmented the level of L. acuta GCLC transcripts in a dose-dependent manner. These gene expression results can be related to the known cadmium effect on GSH depletion. Since a number of contaminants can also exert their toxicity through this mechanism, GCLC gene expression might be applied not only for cadmium biomonitoring, but also for a wide range of contaminants that directly or indirectly promote the same effect in the cellular GSH content.

Amino Acid Sequence↗
PubMed2005

Limited microbial degradation of pyrene metabolites from the estuarine polychaete Nereis diversicolor.

We compared microbial mineralization of [4,5,9,10-14C]pyrene and its eukaryotic [4,5,9,10-14C]pyrene metabolites in estuarine sediments. Metabolites were obtained by exposing the estuarine deposit-feeding polychaete Nereis diversicolor to sediment-associated 14C-pyrene, followed by homogenization of the worms and extraction of the pyrene-metabolites. In sediment from a pristine Danish Fjord only 2.6% of the added metabolite-label and 1.7% of the pyrene-label were mineralized to 14CO2 during 175 days incubation. Pre-exposure of the pristine sediment to unlabelled pyrene for 60 days increased the mineralization potential for 14C-pyrene substantially, as 81.2% was mineralized to 14CO2 during 95 days incubation, whereas 14C-pyrene metabolite label was unaffected by pre-exposure to pyrene. In comparison, naturally aged bunker-oil contaminated sediment did not show elevated potentials for mineralization of neither 14C-pyrene nor 14C-metabolites. Six bacterial strains of known pyrene degraders were tested for growth on crystalline 1-hydroxypyrene. 1-Hydroxypyrene is the only intermediate eucaryotic metabolite of pyrene. The results indicate that 1-hydroxypyrene was not utilized as a sole source of carbon and energy by any of them. In addition, respiration was depressed in all six strains when exposed to crystalline 1-Hydroxypyrene, demonstrating an acute toxic effect of 1-hydroxypyrene. The results presented here suggest that microbial degradation of pyrene is not enhanced by release of aqueous and polar metabolites by marine invertebrates.

Animals↗
PubMed2006

Uptake and loss of dissolved 109Cd and 75Se in estuarine macroinvertebrates.

Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), followed by exposure to radionuclide-free water for 189 h (loss phase). The whole body uptake rates of (75)Se by pygmy mussels, semaphore crabs and soldier crabs were 1.9, 2.4 and 4.1 times higher than (109)Cd, respectively. There were no significant (P>0.05) differences between the uptake rates of (75)Se and (109)Cd for ghost shrimps and polychaetes. The uptake rates of (109)Cd and (75)Se were highest in pygmy mussels; about six times higher than in soldier crabs for (109)Cd and in polychaetes for (75)Se - the organisms with the lowest uptake rates. The loss rates of (109)Cd and (75)Se were highest in semaphore crabs; about four times higher than in polychaetes for (109)Cd and nine times higher than in ghost shrimps for (75)Se - the organisms with the lowest loss rates. The loss of (109)Cd and (75)Se in all organisms was best described by a two (i.e. short and a longer-lived) compartment model. In the short-lived, or rapidly exchanging, compartment, the biological half-lives of (75)Se (16-39 h) were about three times greater than those of (109)Cd (5-12h). In contrast, the biological half-lives of (109)Cd in the longer-lived, or slowly exchanging compartment(s), were typically greater (1370-5950 h) than those of (75)Se (161-1500 h). Semaphore crabs had the shortest biological half-lives of both radionuclides in the long-lived compartment, whereas polychaetes had the greatest biological half-life for (109)Cd (5950 h), and ghost shrimps had the greatest biological half-life for (75)Se (1500 h). This study provides the first reported data for the biological half-lives of Se in estuarine decapod crustaceans. Moreover, it emphasises the importance of determining metal(loid) accumulation and loss kinetics in keystone prey items, which consequently influences their trophic transfer potential to higher-order predators.

Animals↗
PubMed2003

Arthropod-like expression patterns of engrailed and wingless in the annelid Platynereis dumerilii suggest a role in segment formation.

The origin of animal segmentation, the periodic repetition of anatomical structures along the anteroposterior axis, is a long-standing issue that has been recently revived by comparative developmental genetics. In particular, a similar extensive morphological segmentation (or metamerism) is commonly recognized in annelids and arthropods. Mostly based on this supposedly homologous segmentation, these phyla have been united for a long time into the clade Articulata. However, recent phylogenetic analysis dismissed the Articulata and thus challenged the segmentation homology hypothesis. Here, we report the expression patterns of genes orthologous to the arthropod segmentation genes engrailed and wingless in the annelid Platynereis dumerilii. In Platynereis, engrailed and wingless are expressed in continuous ectodermal stripes on either side of the segmental boundary before, during, and after its formation; this expression pattern suggests that these genes are involved in segment formation. The striking similarities of engrailed and wingless expressions in Platynereis and arthropods may be due to evolutionary convergence or common heritage. In agreement with similarities in segment ontogeny and morphological organization in arthropods and annelids, we interpret our results as molecular evidence of a segmented ancestor of protostomes.

Animals↗
PubMed2006

Hedistin: A novel antimicrobial peptide containing bromotryptophan constitutively expressed in the NK cells-like of the marine annelid, Nereis diversicolor.

A novel antimicrobial peptide, named hedistin was identified from the coelomocytes of Nereis diversicolor. Hedistin shows no obvious similarities with other known peptides and constitutes the first antimicrobial peptide containing bromotryptophans demonstrated in annelids. cDNA and mass spectrometry analysis revealed that, upon bacteria challenge, this peptide is secreted following processing of a precursor containing a signal peptide and prosequences. Hedistin was shown to possess an activity against a large spectrum of bacteria including the methicillin resistant Staphylococcus aureus and Vibrio alginolyticus. The gene was demonstrated to be constitutively and exclusively expressed in circulating NK cells like known to play an important role in the immunity of the sand worm. These data contrast with those observed in another annelid, the leech, in which genes coding for antimicrobial peptides are upregulated in a specific tissue and peptides are rapidly released into the hemolymph after septic injury.

Amino Acid Sequence↗
PubMed2005

In situ relationship between energy reserves and steroid hormone levels in Nereis diversicolor (O.F. Müller) from clean and contaminated sites.

The aim of this study was to investigate, in situ, the temporal effects of urban effluent discharge on energy reserves and steroid hormone levels in the intrasedimentary worm Nereis diversicolor. Results have shown no differences in energy reserves (glycogen, lipids) in organisms originating from a contaminated site (Oued Souss) and a comparatively clean site (Oualidia). Both sites are located on the Moroccan Atlantic coast. In contrast, steroid hormone (progesterone, testosterone, and 17beta-estradiol) levels were significantly decreased in animals from Oued Souss. The differences in the responses suggest that organisms from the polluted site have been exposed to endocrine disruptors.

Animals↗
PubMed2006

From biomarkers to population responses in Nereis diversicolor: assessment of stress in estuarine ecosystems.

Suborganismal responses to toxicants can be sensitive tools to assess marine pollution, but their ecological significance is a matter of debate. Among these biomarkers, those linked to reproduction are most probably related to populational effects. To test this hypothesis, Nereis diversicolor were collected in the multipolluted Seine estuary and the comparatively clean Authie estuary (France). Energy reserves were higher in Authie worms, suggesting a better physiological status. The number of oocytes per female was higher for the polychaetes from the Authie, but it was related to the size of animals, which was higher at this site. Densities of worms were depleted in the Seine compared to those in Authie. Demographic structure of the Seine population was also altered. The concomitant changes in energy reserves, egg production, and population structure and density suggest that the effects on biomarkers and at the population level are related.

Animals↗
PubMed2006

The ultrastructure and reproduction of Amphiamblys capitellides (Microspora, Metchnikovellidae), a parasite of the gregarine Ancora sagittata (Apicomplexa, Lecudinidae), with redescription of the species and comments on the taxonomy.

The ultrastructural cytology and reproduction of the hyperparasitic microsporidium Amphiamblys capitellides (Caullery and Mesnil, 1897) is described. Merogonial reproduction was not observed. The sporogony comprises two sequences: a sac-bound sporogony in close contact with the cytoplasm of the host and a free sporogony in parasitophorous vacuoles. The free sporogony, which probably precedes the sac-bound, yields a small number of rounded spores. The sac-bound sporogony is polysporoblastic, generating two rows of elongated spores. All stages have isolated nuclei. Both spore types have an extrusion apparatus of the metchnikovellidean type, with a polar sac devoid of anchoring disc, a polar filament with one manubroid and one bulbous part, and a posterior semicircular membrane fold enclosing rounded or tubular structures. Hosts are gregarines of the species Ancora sagittata living in the intestine of polychaetes of the genus Capitella, probably the species Capitella giardi. The cytology, life cycle and classification are discussed. The species is redescribed and the diagnosis of the genus Amphiamblys Caullery and Mesnil, 1914 is emended.

Animals↗
PubMed2005

Bacterial extracellular polymeric substance (EPS): a carrier of heavy metals in the marine food-chain.

The ecological implications of metal binding properties of bacterial EPS and its possible role in the bioaccumulation of pollutants in the marine food-chain was investigated using a partially purified and chemically characterized microbial EPS isolated from a species of Marinobacter. Various factors influencing metal sorption by the EPS including the influence of initial metal concentrations, incubation time, pH and sodium chloride concentrations on binding of lead (Pb2+) and copper (Cu2+) were evaluated. The bacterial EPS selectively bound more amount of Cu2+ per mg of EPS than Pb2+. Both copper and lead were sorbed more at near neutral pH than acidic pH. The sorption of Cu2+ increased with increasing copper concentration. The estimated maximum binding ability (MBA) of the EPS was 182 nmol copper and 13 nmol lead mg(-1) EPS. However, the sorption of these metals decreased with the increase in sodium chloride concentration. Furthermore, up to 35% of 14C-labeled Marinobacter was ingested by a benthic polychaete Hediste diversicolor. On an average, 29% of the ingested EPS was absorbed into tissues and 49% of the EPS was respired. It was apparent that the animals used the EPS as a source of energy and nutrition. The labile nature of the bacterial EPS and its ability to bind heavy metals might route the bound metals through the marine food chain, thereby transferring and aiding bioaccumulation of metal pollutants in the higher trophic animals.

Adsorption↗
PubMed2005

Interspecific variation in heavy metal body concentrations in biota of Sunderban mangrove wetland, northeast India.

The coastal environment of West Bengal, recognized as the most diversified and productive ecosystem among all the maritime states of India, faces organic pollution from domestic sewage and urban and industrial effluents leading serious impacts on biota. The present paper aims at providing information on concentration level of heavy metals among the tissues of benthic polychaetes, bivalve molluscs and finfishes collected from Sundarban mangrove wetland, northeast coast of India. An overall common trend in bioaccumulation was revealed with the following decreasing order: Zn>Mn>Cu>Cr>Se>Hg with few exceptions. Both species dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs. Variability between closely related species is a reflection of different uptake rates, physiology and impact of environmental factors. The results of this analysis suggest that mollusks can play a significant role in trace metal trophic transfer studies, especially as their representatives are intertidally and subtidally ubiquitous.

Animals↗
PubMed2006

Liquid versus solid phase bioassays for dredged material toxicity assessment.

Since 1994 the results of the analyses of key chemical compounds (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) and the comparison with the corresponding sediment quality guidelines (SQGs) are used in decision-making for dredged material management in Spain. Nonetheless in the last decades a tiered testing approach is promoted for assessing the physical and chemical characteristics of dredged sediments and their potential biological effects in the environment. Bioassays have been used for sediment toxicity assessment in Spain but few or no experiences are reported on harbour sediments. We studied the incidence of toxicity in the 7 d bioassay using rotifers (Brachionus plicatilis) and the 48 h bioassay using sea urchin (Paracentrotus lividus) embryos over a series of experiments employing 22 different elutriates. The relative performance of this exposure phase was not comparable to data on the 10-d acute toxicity test using the burrowing amphipod Corophium volutator and the polychaete Arenicola marina, carried out on the whole sediments. These results evidence the importance of the exposure route and the test selected in decision-making, as the toxicity registered for the undiluted elutriates was largely due to the different solubility of sediment-bound contaminants. This work and other studies indicate that for many sediments, a complete battery of test is recommended together with physico-chemical analyses to decide whether dredged sediments are suitable for open water disposal or not.

Animals↗
PubMed2006

Development and validation of a behavioural assay to measure the tolerance of Hediste diversicolor to copper.

The behaviour of Hediste diversicolor from the Humber was investigated under different concentrations of copper sulphate. A range of behaviours were indicative of metal-stress. These included consistent attempts at burrowing, eversion of the proboscis and abnormal crawling. The bioassay itself consisted of exposing worms to increasing concentrations of copper sulphate and recording the concentration at which a stress response was elicited. The behavioural end-points were shown to be a good predictor of time of death of Fal estuary worms under acutely toxic conditions. The bioassay would therefore allow the separation of tolerance phenotypes without mortality to the worm. Worms were not affected by consecutive bioassays and it was proposed that tolerance to more than one metal could be determined for individual worms.

Animals↗
PubMed2005

Effects of teflubenzuron on sediment processing by members of the Capitella species-complex.

The cosmopolitan deposit-feeding polychaete Capitella is widely used as an indicator of organic pollution and plays an important role in waste recycling at aquaculture sites. Teflubenzuron is currently employed by salmon farms as an in-feed compound to control ectoparasite infestations. Its occurrence in sediments could pose a hazard to local sediment infauna. A bioassay to investigate the effects of exposing Capitella sp I and Capitella sp B to sediment spiked with environmentally relevant concentrations of teflubenzuron (8.4, 25 and 41.8 microg/g dry wt. sediment) is described. No mortality was recorded for Capitella sp I, but increasing teflubenzuron concentrations significantly reduced egestion rates. Capitella sp B exhibited mortality, although egestion was not affected. These results using Capitella spp. indicated that teflubenzuron could affect the rate of sediment processing by polychaetes close to fish farms treated with this compound. Further studies are recommended to assess the potential of contaminants in aquaculture wastes.

Animal Feed↗
PubMed2006

Development and application of long-term sublethal whole sediment tests with Arenicola marina and Corophium volutator using Ivermectin as the test compound.

Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required.

Amphipoda↗
PubMed2004

Post mortem cohabitation-shell growth as a measure of elapsed time: a case report.

A partial calvaria, dredged from the sea-bed some years previously, was referred to us for examination. The presence of a well-established mollusc colony on the vault allowed us to establish a minimum elapsed time since death. Such a cross-disciplinary co-operative study is of great advantage in expediting a satisfactory conclusion.

Animals↗
PubMed2004

Alternative splicing produces transcripts coding for alpha and beta chains of a hetero-dimeric phosphagen kinase.

Glycocyamine kinase (GK) catalyzes the reversible phosphorylation of glycocyamine (guanidinoacetate), a reaction central to cellular energy homeostasis in certain animals. GK is a member of the phosphagen kinase enzyme family and appears to have evolved from creatine kinase (CK) early in the evolution of multi-cellular animals. Prior work has shown that GK from the polychaete Neanthes (Nereis) diversicolor exits as a hetero-dimer in vivo and that the two polypeptide chains (termed alpha and beta) are coded for by unique transcripts. In the present study, we demonstrate that the GK from a congener Nereis virens is also hetero-dimeric and is coded for by alpha and beta transcripts, which are virtually identical to the corresponding forms in N. diversicolor. The GK gene from N. diversicolor was amplified by PCR. Sequencing of the PCR products showed that the alpha and beta chains are the result of alternative splicing of the GK primary mRNA transcript. These results also strongly suggest that this gene underwent an early tandem exon duplication event. Full-length cDNAs for N. virens GKalpha and GKbeta were individually ligated into expression vectors and the resulting constructs used to transform Escherichia coli expression hosts. Regardless of expression conditions, minimal GK activity was observed in both GKalpha and GKbeta constructs. Inclusion bodies for both were harvested, unfolded in urea and alpha chains, beta chains and mixtures of alpha and beta chains were refolded by sequential dialysis. Only modest amounts of GK activity were observed when alpha and beta were refolded individually. In contrast, when refolded the alpha and beta mixture yielded highly active hetero-dimers, as validated by size exclusion chromatography, electrophoresis and mass spectrometry, with a specific activity comparable to that of natural GK. The above evidence suggests that there is a preference for hetero-dimer formation in the GKs from these two polychaetes. The evolution of the alternate splicing and an additional exon in these GKs, producing alpha and beta transcripts, can be viewed as a possible compensation for a mutation(s) in the original gene, which most likely coded for a homo-dimeric protein.

Alternative Splicing↗