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1.
Our intent has been to develop rapid and sensitive bioassay procedures for laboratory and field applications based on hemolymph factors in animals such as the bay mussel, Mytilus edulis. We found that mussel hemolymph could be easily and repeatedly sampled from individual animals in sufficient amounts to allow analyses for lysozyme, proteolytic activity, total protein and hemocyte counts. In static tests there seemed to be graded responses indicating release of increasing amounts of the above factors into the hemolymph in roughly direct proportion to Cu2+ concentration at lethal and sublethal levels. We interpreted this to be evidence for increased lysosomal and cellular disruption as cupric ion exposure was increased or prolonged. At the same time, Cu2+ concentrations in the mussel hemolymph increased up to an order of magnitude above ambient in the range of 26 to 267 ppb. We felt that this was evidence for the release of Cu-binding proteins into the mussel hemolymph. Simultaneously with the above events the serum granulocytes increased in numbers above control values by factors of 3 or 4 in response to copper challenge while macrophage (terminology of Moore & Lowe, 1977) counts, including controls, declined precipitously.  相似文献   

2.
DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mussels collected in 3 sampling areas of the French coast (Pointe du Castelli, Pen Bron and Saint-Nazaire Harbour). Whole mussel tissue samples were also collected for the chemical determination of PAH, PCB and heavy metal concentrations. In mussel, a higher level of DNA strand breaks was measured in gill than in hemolymph cells (p < 0.01). Despite a factor of contamination from 2 to 3 between sites, no difference in the extent of mussel DNA strand breaks was shown between sampling locations (p > 0.05), questioning the sensitivity of the assays used in biomonitoring studies.  相似文献   

3.
In a previous study we monitored fluctuations in the concentration of lysozyme in the hemolymph of copper stressed bay mussels, Mytilus edulis, concurrently by measuring enzymatic activity and by an enzyme-linked immunosorbent assay (ELISA).1 In a number of instances the data collected by the two techniques from copper stressed mussels yielded contradictory results. In these instances the quantity of lysozyme, determined enzymatically, was significantly greater than the quantities determined by ELISA. These results prompted subsequent investigation into the cause of the discrepancies. In the course of the study a high molecular weight protein fraction (35 000 MW) from mussel hemocytes was isolated. Decreasing the ionic strength and concentration of the fraction caused dissociation into a 14 600 MW fraction characteristically identical to lysozyme.2 Association to the 35 000 MW form is reversible upon an increase in ionic strength and concentration, and is presumed to be a dimer of lysozyme.3,4 The ionic strength and pH optima for hydrolysis of suspensions of Micrococcus luteus were determined for the dimer. Polyclonal anti-lysozyme gammaglobulin preparations1 were used in determinations of the relative immunological reactivity of various lysozyme preparations by immunodiffusion.5 The monomer form was more favorably precipitated or detectable than the lysozyme in hemocytes. disturbed hemocytes indicate an apparent increase in the extracellular concentration of the dimer as a result of cell damage. The observed low immunological reactivity would allow for the lack of detection by ELISA, and may have interfered with antibody-monomer interactions.  相似文献   

4.
Sub-cellular perturbations in the lysosomal compartment of molluscan haemocytes were examined in mussels (Perna viridis), collected along a pollution gradient. The neutral red technique was validated using a well defined contamination gradient among indigenous populations from five stations along Tolo Harbour, Hong Kong. Condition indices (shell length:dry tissue wt) and tissue metal concentrations were also measured in an attempt to identify a relationship between contamination level and adverse physiological effects. Correlations were found between lysosomal retention time and condition along the pollution gradient. There were significant differences between mussels collected from stations on offshore islands and those collected from inner harbour sites (p < 0.05). There was, however, little correlation between metal concentrations and retention time or condition (p > 0.05).  相似文献   

5.
An ecotoxicological protocol with caged mussels, Mytilus galloprovincialis, was developed to evaluate the potential impact of an offshore gas platform in the central Adriatic Sea. Reference organisms were collected on a seasonal basis from an unpolluted site and transplanted for four weeks in both the sampling area and to the investigated platform. Chemical analyses of trace metals in mussel tissues were integrated with a multi-biomarker approach for the early detection of biological responses at several cellular targets. Induction of metallothioneins, peroxisomal proliferation and activity of acetylcholinesterase were measured as markers for specific classes of chemicals. Special attention was given to oxyradical metabolism and appearance of oxidative-mediated toxicity to reveal a more general onset of cellular disturbance. In addition to individual antioxidants (superoxide dismutase, catalase, glutathione S-transferases, glutathione reductase, Se-dependent and Se-independent glutathione peroxidases, and levels of total glutathione), the total oxyradical scavenging capacity (TOSC) allowed a quantification of the overall capability to neutralize specific forms of intracellular reactive oxygen species (ROS; i.e. peroxyl and hydroxyl radicals). Cellular damages were evaluated as lysosomal destabilization (membrane stability, accumulation of lipofuscin and neutral lipids), lipid peroxidation products (malondialdehyde) and DNA integrity (strand breaks and micronuclei); the air survival test was finally applied to evaluate the overall physiological condition of mussels. Concentration of trace metals (As, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn) revealed only limited variations in transplanted mussels during various experimental periods and such changes appeared partly related to natural fluctuations. Among biological responses, variations of antioxidants and lysosomal stability were confirmed as sensitive early warning signals for biological disturbance of both natural and anthropogenic origin. The presented protocol with caged mussels allowed marked biological effects caused by the investigated platform to be excluded, and represented a useful approach that is easy to extend for monitoring the impact of offshore activities in the Adriatic sea.  相似文献   

6.
The aim of this study was to examine whether a combination of biochemical, histopathological and toxicogenomic data could be used as a valuable tool for the assessment of biological risk associated with pollutants within the Tamar River and Estuary, S.W. England, U.K. Accordingly, biochemical and histopathological biomarkers (protein carbonyls, lipofuscin, neutral lipids, lysosomal stability [N-acetyl-β-hexosaminidase and neutral red], lysosomal volume, ferric reducing antioxidant power [FRAP] and malonaldehyde [MDA]) and gene expression profiles were assessed in 5 sites from the Tamar River and Estuary (Neal Point, Town Quay, Wilcove, Cremyll Ferry and Whitsand; and a reference site, Trebarwith Strand, N. Cornwall). PAHs were measured in mussel tissue and sediment and metals were measured in mussel tissue only. Data from the biomarkers was integrated into a Mussel Expert System (MES) model to produce a simple assessment of mussel stress. Clear gradients of mussel toxicity were identified by the biomarkers (with the exception of neutral lipids) with the highest impacted animals found furthest up the Tamar, whilst the MES was unable to identify a gradient of effect. Gene expression profiles also indicated a gradient of stress with the greatest number of significantly up- or down- regulated genes found at the uppermost 2 sites. The MES did, however, determine that mussels from all sites, except the reference site, were highly stressed; a conclusion that could not be inferred from the biomarker data alone. It is concluded that the MES is a valuable tool that permits integration and interpretation of complex sets of biomarker data by identifying the biological meaning of biomarker changes.  相似文献   

7.
Pacific oysters (Crassostrea gigas Thunberg 1793) have been introduced into the Wadden Sea (North Sea), where they settle on native mussel beds (Mytilus edulis L.), which represent the only extensive insular hard substrata in this soft-sediment environment. As abundances of C. gigas rose, some mussel beds became increasingly overgrown with oysters, whereas others did not. Field experiments revealed that recruitment of C. gigas was higher in the lower intertidal than in the upper subtidal zone, that it was higher on conspecifics than on mussels, and that it was not affected by barnacle epigrowth except when settling on mussels. Mussel recruitment is known from inter- and subtidal zones. It occurred equally on oyster and mussel shells but showed a clear preference for barnacle epigrowth over clean shells. Assuming that settlement and recruitment are key processes for species abundances on the North Sea coast, it is predicted that the positive feedback in oyster settlement will lead to rapid reef formation of this invader at the expense of mussel beds. Mussels, however, may escape competitive exclusion by settling between or on the larger oysters especially when barnacles are abundant. Experimental patches with mussels were more often covered by fucoid algae (Fucus vesiculosus forma mytili Nienburg) than patches with oysters, and oyster recruitment was poor underneath such algal canopies. Thus, fucoids may provide the native mussels with a refuge from the invading oysters and the two bivalves may coexist, provided food is not limiting.  相似文献   

8.
The primary-secondary settlement hypothesis, that mussels first settle in algae and then move to mussel beds, was rejected as the only mode of recruitment for the brown mussel Perna perna in a previous study at one location over one year on the south coast of South Africa. We investigated recruitment of P. perna into mussel beds and algal turfs over a five-year period (1995–2000) at 3–4 sites at each of four locations on the South and East coasts. Attachment to the two substrata was significantly temporally synchronous at two of the four locations. The disparity among locations could be due to differences in the algal species present or to differences in the importance of turf algae as a facilitator of recruitment. At Zululand, on the East Coast, attachment to mussel beds and algae was measured monthly and found not to be temporally synchronous. At this location, primary settlement into algae was significantly correlated with an increase in the density of juveniles in the mussel beds 2–3 months later, indicating that turf algae can act as irregular but important facultative facilitators of mussel recruitment, supplementing direct input into the mussel beds. However, as amounts of settlers and recruits in mussel beds exceeded those found in algal turfs most years and places, the primary-secondary settlement hypothesis is inapplicable to P. perna under most circumstances.  相似文献   

9.
Bathynerita naticoidea (Gastropoda: Neritidae) is a numerically dominant heterotrophic gastropod found at hydrocarbon seep sites on the upper Louisiana slope of the Gulf of Mexico. Snails of this species are commonly associated with beds of the methanotrophic mussel Bathymodiolus childressi (Bivalvia: Mytilidae), and their population structure mirrors that of the mussels they are found among. Previous studies have shown that these snails feed on bacteria and decomposing periostracum on the B. childressi shell. We predicted that B. naticoidea might be attracted to cues specific to its preferred habitat, such as dissolved methane, mucus from conspecific snails, or metabolites produced by B. childressi mussels. To examine this, we used a flow‐through Y‐maze system to investigate the behavior of B. naticoidea exposed to these potential cues. We found that the nerite is not attracted to methane, but is strongly attracted to seawater conditioned with B. childressi. The attractant appears to be specific to this type of mussel, and is not a soluble cue produced by conspecific snails.  相似文献   

10.
用紫色蚌和非紫色蚌制取细胞小片,分别插入紫色蚌和非紫色蚌外套膜内,探究三角帆蚌(Hyriopsis cumingii)无核珍珠颜色与制片蚌、育珠蚌的关系;用不同类型制片蚌的不同部位制取细胞小片,分别插入育珠蚌外套膜内,进一步探究珍珠颜色与制片蚌珍珠质颜色的关系。结果表明,以紫色蚌为制片蚌,所产的珍珠为紫色系,珍珠紫色深浅与细胞小片所对应部位的制片蚌珍珠质紫色深浅呈正相关。以非紫色蚌为制片蚌,所产的珍珠有白色系和黄色系,珍珠黄色深浅与细胞小片所对应部位的制片蚌珍珠质黄色深浅呈正相关。三角帆蚌外套膜无核珍珠颜色是由提供细胞小片的制片蚌珍珠质颜色所决定,而与育珠蚌无关。该结论支持珍珠囊表皮细胞来自于移植细胞小片的观点。该结果表明,通过定向选育纯紫、纯白色贝壳珍珠质三角帆蚌新品系,即可培育出纯紫、纯白色无核珍珠。  相似文献   

11.
Although the Danish Wadden Sea is of international importance for several bird species, large-scale blue mussel Mytilus edulis fishing took place from 1984–1987, ceasing thereafter due to low mussel stocks. Mussel fishing removes much of the blue mussel biomass, especially larger individuals. Hence we predict that intensive mussel fishing will affect their predators, such as the Eider Somateria mollissima, which is predominantly a blue mussel feeder by, 1) reducing the amount of blue mussels in their diet relative to alternative prey items, 2) exploitation of smaller blue mussel shell classes, 3) loss of body condition, 4) changing feeding distribution to aggregate to the remaining mussel stocks, and 5) decreasing numbers. Before winter 1986/87 blue mussel biomass was estimated at 40,600 tons, decreasing to 15,400 tons in 1987/88 due to mussel fishery. We collected Eiders in both periods to monitor their diet and body mass and used aerial surveys to determine changes in numbers and distribution. Between the two periods, blue mussels declined in the Eiders diet, numbers of Eiders with empty stomachs increased and the mean length of blue mussel taken by Eiders decreased. Eider body condition declined from 1986/87 to 1987/88, mostly the result of the reduction in numbers of individuals with blue mussel remains in their gizzards and in better body condition compared to those taking alternative food items or having empty gizzards. Eiders shifted their distribution from the southern part of the Danish Wadden Sea to the northern part, where the remaining blue mussel stocks were situated. Eider numbers were lowest in 1987/88, the year of lowest blue mussel stocks. We conclude that intensive mussel fishery affected the Eider's diet, reduced their body condition and affected distribution and abundance. The results also showed that availability of blue mussels may have a key role in building up and maintaining body condition in Eiders during winter.  相似文献   

12.
The Eiffel Tower edifice is situated in the Lucky Strike hydrothermal vent field at a mean depth of 1690 m on the Mid‐Atlantic Ridge (MAR). At this 11‐m‐high hydrothermal structure, different faunal assemblages, varying in visibly dominant species (mussels and shrimp), in mussel size and in density of mussel coverage, were sampled biologically and chemically. Temperature and sulphide (∑S) were measured on the different types of mussel‐based assemblages and on a shrimp‐dominated assemblage. Temperature was used as a proxy for calculating total concentrations of CH4. Based on the physico‐chemical measurements, two microhabitats were identified, corresponding to (i) a more variable habitat featuring the greatest fluctuations in environmental variables and (ii) a second, more stable, habitat. The highest temperature variability and the highest maximum recorded temperatures were found in the assemblages visibly inhabited by alvinocaridid shrimp and dense mussel beds of large Bathymodiolus azoricus, whereas the less variable habitats were inhabited by smaller‐sized mussels with increasing bare surface in between. Larger mussels appeared to consume more ∑S compared with smaller‐sized (<1 cm) individuals and thus had a greater influence on the local chemistry. In addition, the mussel size was shown to be significantly positively correlated to temperature and negatively to the richness of the associated macrofauna. The presence of microbial mats was not linked to specific environmental conditions, but had a negative effect on the presence and abundance of macro‐fauna, notably gastropods. Whereas some taxa or species are found in only one of the two microhabitats, others, such as polychaetes and Mirocaris shrimp, cross the different microhabitats. Temperature was proposed to be a more limiting factor in species distribution than ∑S.  相似文献   

13.
A fungal epizootic in mussels at a deep-sea hydrothermal vent   总被引：1，自引：0，他引：1  
Mass mortalities due to disease are important determinants of population and community structure in marine ecosystems, but the speed at which an epizootic may sweep through a population, combined with rapid selection for disease‐resistant stocks, can mask the ecological impact of disease in all but the most closely monitored populations. We document an emergent epizootic event in the deep sea that is occurring in mussels (Bathymodiolus brevior) at the Mussel Hill hydrothermal vent in Fiji Basin and we identify the causal agent as a black yeast (order Chaetothyriales) that elicits a pronounced host immune response and is associated with tissue deterioration. The yeast was not observed in other invertebrate taxa (the gastropods Ifremeria nautilei, Alviniconcha aff. hessleri; the limpets Lepetodrilus schrolli, Symmetromphalus aff. hageni; the polychaetes Branchipolynoe pettiboneae, Amphisamytha cf. galapagensis) associated with the mussel bed, nor in mussels (Bathymodiolus brevior) collected from adjacent Lau Basin mussel beds. Massive mussel mortality resulting from the fungal infection is anticipated at the Mussel Hill site in Fiji Basin; we expect that epizootic outbreaks in dense invertebrate communities have the potential to be major determinants of community structure in deep‐sea chemosynthetic ecosystems. The possibility that submersible assets may serve as vectors for transport of the fungus warrants further attention.  相似文献   

14.
Many cellular and sub-cellular biomarkers associated with mussel (Mytilus edulis) digestive gland and kidney have been characterised. The lysosomal compartment of these tissues have been recognised as being particularly sensitive, exhibiting pollutant induced responses which could be potentially used as a ‘biomarker’. However, relatively few studies have investigated the lysosomal response within molluscan hemocytes. This study was conducted to test whether lysosomal reactions, in live hemocytes isolated from mussels, can be used as a biomarker of pollutant exposure and deleterious effect. Lysosomal responses to a number of hydrocarbons, including anthracene and phenanthrene, and to the amphiphilic heterocylic chemical, chlorpromazine, were examined. The supravital dye neutral red (NR) was used to examine lysosomal membrane fragility, following xenobiotic exposure. NR was also used to verify the lysosomal compartment as the reported accumulation site of a new molecular probe, BODIPY-FL-verapamil (BFLV). The use of BFLV, with confocal laser microscopy and image analysis enabled visualisation and quantification of lysosomal distribution and perturbation. BFLV showed that exposure of molluscan hemocytes to xenobiotics (20 ppb–10 ppm) induced the formation of pathologically enlarged lysosomes. The internal trafficking of lysosomes was shown to be severely compromised after exposure to chlorpromazine. Exposed molluscan hemocytes exhibited significantly reduced lysosomal retention times, for neutral red. Preliminary data is presented demonstrating the opportunity for these non-destructive biomarker techniques to detect pollution gradients in situ.  相似文献   

15.
Studies were performed on the common mussel, M. edulis L., to determine whether copper (Cu) exposure can affect the extent to which digestive cell proteins are oxidised and whether such oxidative damage is mediated by free radicals. Three age groups of mussels were exposed for 6 -days to environmentally realistic concentrations of Cu and then digestive gland homogenates were examined for evidence of protein carbonyl formation. Significant increases in carbonyls relative to untreated control mussels were seen for the youngest (2–4 year-old) and oldest (≥ 10 year-old) mussels only after exposure for 6 days, followed by recovery from exposure for a further 6 days. Untreated mussels also showed an age-related difference in protein oxidation, with a significantly lower concentration in the youngest animals (2–4 year olds). Copper did not affect the levels of modified tryptophan or tyrosine residues or the extent of total lipid peroxidation in digestive gland homogenate. Significant depletion of total vitamin E (a-tocopherol) was seen only in young and medium-aged mussels following exposure for 6 days. The levels of protein carbonyl groups were increased in digestive cell cytosol and lighter lysosomes but not in heavier lysosomes or digestive gland microsomes following 5 days exposure to Cu. Dihydrohodamine-123 was converted to fluorescent rhodamine-123 following sequestration into digestive cell lysosomes. The results suggest a link between the lysosomal sequestration of copper, a concomitant increase in the production of oxyradicals and the potential for intracellular oxidative damage, as well as an increased capacity for oxidative damage in older animals.  相似文献   

16.
A field study was carried out in the Lagoon of Venice (north-east Italy) with the aim of evaluating the potential use of lysosomal destabilisation as a biomarker of anthropogenic stress in the autochthonous mussel Mytilus galloprovincialis. Two different approaches were adopted in biomonitoring six sites in the Lagoon, evaluating indigenous populations of mussels and organisms transplanted from a reference site and checked at several points in time. Lysosomal membrane stability was investigated by means of two tests: neutral red retention assay (NRRA) for evaluating haemocyte lysosomes and lysosomal latency test (LLT) for digestive cell lysosomes. Results indicate that the lysosomal response measured in haemocytes according to NRRA is a more valuable biomarker of anthropogenic stress in the framework both of passive and active biomonitoring in marine coastal environments.  相似文献   

17.
Intertidal population dynamics are driven by a complex series of processes, including larval supply and the possibility of larval predation by benthic animals such as filter-feeders. We hypothesised that cannibalism by adults could play a major role in the population connectivity of mussel populations by removing larvae as they attempt to settle in the adult habitat. Specifically, we tested hypotheses that consumption of mussel larvae by adults removes a significant proportion of potential settlers and is influenced by both settlement intensity and tidal state (flooding or ebbing). Predation of mussel larvae by adult mussels was investigated on incoming and ebbing tides during four spring tides by analysing the gut contents of adult Perna perna and Mytilus galloprovincialis collected from the low intertidal mussel zone between October 2005 and January 2006. Consumption rates were then compared with estimates of successful settler densities on natural beds. The results showed that mortality of competent mussel larvae through adult ingestion removes up to 77% a of potential settlers. Rates of larval consumption were highest during months of intense settlement, suggesting that mussels feed opportunistically, filtering a relatively fixed volume of water and removing particles, including larvae, in proportion to their densities in the water. Rates of larviphagy were also higher during receding than incoming tides. We suggest that this is due to changes in larval density or, more probably, in adult filtration efficiency that are related to the state of the tide. Despite significant effects of both tidal state and settlement intensity on rates of larval ingestion, neither had a significant effect on the proportion of potential settlers removed. During settlement more than half of all potential settlers are lost through cannibalism, with potentially serious consequences for population maintenance. The results highlight the paradoxical nature of the evolution of settlement mechanisms in mussels, which must balance the advantages of settlement in habitats favourable to adults against the consumption of larvae by adults.  相似文献   

18.
贻贝营半固着生活,依靠足丝将自己牢固地黏附在底物上.足丝的结构和性能对贻贝的正常生命活动至关重要.为研究热液区极端环境下深海贻贝足丝的结构和性能,采集了印度洋龙旂深海热液区的贻贝(Bathymodiolus marisindicus)足丝,对其力学特性、结构特征和组分进行了分析.力学性能测试发现与近海贻贝(Mytilu...  相似文献   

19.
An aluminium smelter on the west coast of Scotland discharges an aqueous effluent containing polycyclic aromatic hydrocarbons (PAHs) at the head of Loch Leven. The loch also supports two mussel (Mytilus edulis) farms. Data are presented on burdens of PAHs in the soft tissues of mussels and the effect of these contaminants on glutathione S-transferase (GST) activity in mussel hepatopancreas. GST activity is shown to be correlated with total PAH burden and also with the concentrations of certain individual PAHs. These field data show that high molecular weight PAHs are closely correlated to GST activity, whereas low molecular weight PAHs are not. This suggests that 5- and 6-ring PAHs have a more pronounced role than 2- to 4-ring compounds in inducing GST activity in mussels from Loch Leven. It is proposed that it may be more appropriate to link GST activity with 5- and 6-ring compounds only, rather than with the total PAH burden.  相似文献   

20.
There is a growing body of evidence to suggest that bivalve molluscs routinely ingest zooplankton. To elucidate further these observations, a 15-month study of zooplankton ingestion by farmed mussels was conducted using mussel long-lines in Bantry Bay, Ireland. Stomach content analysis of the mussels showed that there was evidence of zooplankton ingestion throughout the sampling period, but that highest mean numbers of zooplankters were ingested by mussels in the spring and summer months. Various zooplankton species were present in mussel stomachs. Harpacticoid copepods were found more often in stomach contents than calanoid copepods, probably due to their proximity to the bivalves' inhalent siphons. Barnacle cyprids featured in large numbers in stomach contents, but only for a period of 3 months which broadly corresponded with their pelagic phase. Sizes of ingested zooplankton ranged from 126 μm to 6 mm, but more of the smaller zooplankters (e.g. crustacean nauplii) were ingested. When lengths of ingested copepods were compared with those found in plankton net samples, it was found that the net-sampled copepods were significantly larger than those found in mussel stomachs, suggesting that mussels select for smaller categories within the zooplankton available to them. Soft bodied zooplankton was rarely found in mussel stomachs but their absence may be due to rapid digestion or they may have been destroyed in the preservation process. Ingestion of zooplankton by bivalves is discussed in the context of the impacts mussel farms have on resident zooplankton populations.  相似文献   

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