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1.
Expanding industrial activities in the Arctic require an urgent assessment of the toxicity of chemicals at low temperatures. Organisms acclimatized to low temperature exhibit specific adaptations. For example, the amount of unsaturated lipids is increased to maintain the fluidity of the cell membranes. It has been hypothesized that such temperature-induced alterations in membrane lipid composition may affect the stability of lysosomal and cell membranes in the common mussel, Mytilus edulis, an organism exposed to seasonal temperature extremes. As mussels may be exposed to petroleum compounds along industrialized coastlines, we tested the combined effects of exposure to low temperature and the petroleum compound, phenanthrene, on haemocyte membrane stability. Test animals, acclimated to either 0 or 10 degrees C, were exposed to phenanthrene (0 = control or 500 micrograms l-1) and haemocytes were examined using the neutral red retention assay (lysosomal stability) and a fluorescence assay (cell membrane stability). At 0 degree C, lysosomal and cell membranes from uncontaminated mussels were destabilized compared with 10 degrees C (P = 0.0005). No significant effects (P > 0.05) of phenanthrene were detected at either temperature. Possible mechanisms underlying membrane destabilization include a weaker physical resistance of the membrane due to a higher amount of unsaturated lipids, a potentially higher level of reactive oxygen radicals at low temperature and the higher susceptibility of unsaturated lipids to oxidative stress. More work is required to better understand the consequences of this membrane destabilization at low temperature on the susceptibility of the organism to pollutants.  相似文献   

2.
Physiological function emerges from complex biomolecular interactions (e.g., protein–protein) and control mechanisms that enable animals to respond and adapt to changes in their environment. Cell injury and pathology induced by pollutants and other stressors appears to involve the gradual and progressive dysfunction of complex biomolecular interactions, resulting in loss of integrated physiological interactions and homeostasis leading to a reduced capacity to respond effectively to stress. In order to determine whether complexity can be used as an indicator of health, the hypothesis that pathology involves a loss of biological complexity has been tested using a generic physiological interaction network. System complexity was evaluated using Eulerian cycles and connectedness (connectance%) for estimating topological complexity and application of network theory (i.e., analysis of scale-free networks and network diameter). The complexity of the whole system increases when sub-systems, such as detoxication and anti-oxidant protective processes, augmented autophagy, protein degradation and induction of stress proteins, are up-regulated and start to interact significantly as part of a response to low-level stress (i.e., biphasic or hormetic response). However, with increasing severity of stress, cell injury and higher-level functional impairment lead to physiological dysfunction and breakdown of the whole interaction network with consequent loss of complexity. In summary for the model described here, network and graph theory appear to provide a mathematical formalism that can facilitate the system-level interpretation of health and dysfunction in living cells.  相似文献   

3.
Most investigations of the responses of marine organisms to xenobiotics have concentrated on single contaminants and little is known of possible interactive effects of different classes of xenobiotics. As these latter seldom occur in environmental isolation, it is important to understand any interactions (synergistic or antagonistic) which may occur. This problem has been approached in the mussel Mytilus edulis by exposing estuarine mussels to copper (20 μg litre−1) and phenanthrene (100 μg litre−1) both individually and in combination, and measuring cytochemical subcellular and physiological responses after 3 days exposure and 3 days and 12 days recovery period. Results showed that mussels accumulated both xenobiotics during 3 days exposure. Depuration of copper was complete in 3 days recovery period, while loss of phenanthrene ranged from 30% to 70% of the concentration reached after 3 days exposure. There were no interactive effects on depuration.Both copper and phenanthrene reduced lysosomal hydrolase latency in digestive cells, and copper appeared to have a synergistic effect in preventing recovery of latency of lysosomal N-acetyl-β-hexosaminidase during the recovery period. There was evidence, in the digestive cells, of an antagonistic effect of copper on stimulation of activity of the microsomal respiratory chain (measured as NADPH-neotetrazolium reductase) by phenanthrene. Stimulation of this system by phenanthrene persisted after 12 days recovery period. There was a synergistic interaction of copper and phenanthrene on elevation of oxygen consumption and ammonium excretion. Clearance rates and scope for growth (physiological condition) were depressed by copper but not by phenanthrene after 3 days exposure.These findings are discussed in terms of known effects of copper and phenanthrene and the interactions are considered in terms of environmental effects measurements.  相似文献   

4.
Diatom Skeletonema costatum Cleve is one of the main predominant phytoplankton species in the Changjiang Estuary in China. In order to provide some basic information for future assessment of the potential risk on phytoplankton communities in this estuary caused by polycyclic aromatic hydrocarbons(PAHs), this alga was selected as a representative to investigate the photoinduced toxicity of PAHs, in single and mixture. Four PAHs including three-ring phenanthrene and anthracene, four-ring fluoranthene and pyrene were tested in the laboratory. The single toxicity of each PAH on this microalga was compared with and without the simulated solar UV radiation. The results showed that this microalga was sensitive to PAH's photoinduced toxicity. Ratios of the 72 h median effect concentration obtained for fluorescent and UV light tests were about 8.4 for phenanthrene, 13.0 for anthracene, 6.5 for fluoranthene, and 5.7 for pyrene, indicating that UV light enhanced the PAH toxicity to this alga significantly. Under the fluorescent radiation (lacking UV), the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene greater than pyrene greater than anthracene greater than phenanthrene; while under the UV radiation (476 μW/cm2 for UVA, 6.5 μW/cm2 for UVB) it became fluoranthene approximately equaling anthracene greater than pyrene greater than phenanthrene, indicating that the UV light also changed its relative toxicity to this alga. The photoinduced toxicity of PAHs to the marine diatom S. costatum might be a synergistic effect of photosensitization reactions (e.g., generation of single-state oxygen) and photomodification (photooxidation and/or photolysis).The combined effects of six binary mixtures on the marine diatom S. costatum were investigated using the additive-index method. Four binary-mixtures (phenanthrene plus anthracene; phenanthrene plus pyrene; anthracene plus fluoranthene; anthracene plus pyrene) were found to be synergistic joint action mode, while two binary-mixtures (phenanthrene plus fluoranthene; fluoranthene plus pyrene) displayed antagonist, revealing a complex pattern of possible interactions. The combined action mode of PAHs might be related to various factors such as the mixture compounds, mixture ratios and test conditions, etc.  相似文献   

5.
The stability of lysosomes in the digestive cells of Mytilus edulis is affected by changes in both the chemical and physical conditions of the environment.1 This type of response must reflect, at least in part, some change in the organisation of the lysosomal membrane, which is a structure which can be resolved by the electron microscope. However, conventional methods of tissue preparation have produced low contrast images of the digestive gland and damage to the lysosomal membranes. Recently a cryopreparation technique2 has produced lysosomal membrane preparations in the digestive cells of the digestive gland of Mytilus which have high contrast and structural integrity (Fig. 1) in control animals. This method has been used to demonstrate pathological alterations in the lysosomal membrane induced by the polynuclear aromatic hydrocarbon (PNAH) phenanthrene. Anthracene, an isomeric PNAH, had no effect on the morphology of the lysosomal membrane. Phenanthrene also induced apparent proliferation of smooth endoplasmic reticulum in the digestive cells.  相似文献   

6.
Metallothioneins and lysosomes are known to be involved in cellular detoxication and sequestration of certain metals1–3 and both have been identified in this role in elimination of copper from marine mussels (Mytilus edulis/galloprovincialis).3 Cadmium (Cd), however, has been shown to persist in the cells of the digestive gland for long periods with only minimal elimination. An experiment was designed to test the effects of Cd on the fragility of lysosomal membranes in the digestive cells as a measure of cellular injury,4,5 metallothionein content of the digestive gland and cadmium concentration in this organ. Phenanthrene was used also to destabilise lysosomal membranes6 in order to test if increased lysosomal fragility interfered with cadmium metabolism and detoxication. The results demonstrated that Cd induced metallothionein synthesis and that elimination of Cd was minimal after 28 days in clear seawater. Lysosomal fragility was initially increased but this effect was soon reversed, even with continued exposure to Cd. The lysosomal destabiliser, phenanthrene, did not appear to affect accumulation of Cd or levels of metallothionein.  相似文献   

7.
The potential prognostic use of lysosomal reactions to environmental pollutants is explored in relation to predicting animal health in marine mussels, based on diagnostic biomarker data. Cellular lysosomes are already known to accumulate many metals and organic xenobiotics and the lysosomal accumulation of the carcinogenic polycyclic aromatic hydrocarbon 3-methylcholanthrene (3-MC) is demonstrated here in the hepatopancreatic digestive cells and ovarian oocytes of the blue mussel. Lysosomal membrane integrity or stability appears to be a generic indicator of cellular well-being in eukaryotes; and in bivalve molluscs it is correlated with total oxygen and nitrogen radical scavenging capacity (TOSC), protein synthesis, scope for growth and larval viability; and inversely correlated with DNA damage (micronuclei), as well as lysosomal swelling (volume density), lipidosis and lipofuscinosis, which are all characteristic of failed or incomplete autophagy. Integration of multiple biomarker data is achieved using multivariate statistics and then mapped onto "health status space" by using lysosomal membrane stability as a measure of cellular well-being. This is viewed as a crucial step towards the derivation of explanatory frameworks for prediction of pollutant impact on animal health; and has facilitated the development of a conceptual mechanistic model linking lysosomal damage and autophagic dysfunction with injury to cells, tissues and the whole animal. This model has also complemented the creation and use of a cell-based bioenergetic computational model of molluscan hepatopancreatic cells that simulates lysosomal and cellular reactions to pollutants. More speculatively, the use of coupled empirical measurements of biomarker reactions and modelling is proposed as a practical approach to the development of an operational toolbox for predicting the health of the environment.  相似文献   

8.
Lysosomal sequestration of polynuclear aromatic hydrocarbons (PNAHs), a major class of environmental contaminant, is a well-established phenomenon;1 considerably less is known about their pathological effects on lysosomes. Marine molluscs contain a number of lysosome-rich tissues and PNAHs are known to induce deleterious alterations in lysosomal structure and latency of lysosomal enzymes.2 The latter are presumed to involve destabilisation of the lysosomal membrane, resulting in increased permeability and reduced enzyme latency. If lysosomal injury involves derangement of membrane-lipid structure due to the interaction of PNAHs then it would be expected that membrane damage would be closely linked to the structural characteristics of the intruding molecule. Our results show that the effects of the isomeric PNAHs phenanthrene and anthracene on digestive cell lysosomal stability were markedly different in the marine mussel (Mytilus edulis) over the same range of tissue concentrations. Lysosomal membrane stability was determined using a cytochemical test for enzyme latency.3  相似文献   

9.
The purpose of these studies was to evaluate if there were relationships between lysosomal destabilization or glutathione concentrations and gamete viability of oysters, Crassostrea virginica. Oysters were collected from field sites during the peak spawning period (May–June) during 2001 and 2002. Lysosomal destabilization rates and glutathione concentrations of hepatopancreas tissues (e.g. digestive gland) were determined. Eggs and sperm from the same adults were also used to conduct embryo development assays with reference seawater collected from a clean site, site water, and also a range of Cd concentrations (the Cd exposures were used to determine if there were differences in susceptibility to pollutants). Baseline embryo development success (e.g. percent normal development when the assays were conducted with reference seawater or site water) was related to lysosomal destabilization, but not glutathione status. However, the susceptibility of embryos to metal toxicity was related to glutathione status, i.e., sensitivity to Cd exposures increased with decreasing glutathione levels. These studies support the hypotheses that there are linkages between embryo development success and susceptibility to pollutant stress and cellular biomarker responses. These kinds of effects on reproductive success could lead to subtle but significant long-term effects on recruitment and viability of oyster populations.  相似文献   

10.
This laboratory study describes phenanthrene (Ph) and/or anthracene (An) ability to alter the total thiol redox status (TRS), via depletion of protein free thiols (PSH) and glutathione (GSH) levels, in gills of mussel Mytilus galloprovincialis, after a short-term (7 days) exposure period to each contaminant (at a final concentration of 0.1 mg L−1) or in a mixture (ration 1:1, at a final concentration of 0.2 mg L−1). A number of observable changes, like lysosomal membrane impairment (as detected via the neutral red retention time assay, primarily performed in haemocytes), enhancement of lipid peroxidation byproducts, increased nuclear abnormalities, inhibition of AChE and ALP activity, as well as a significant depletion of PSH and GSH were detected in gills of exposed mussels, in any case. Significant relationships occurred among TRS parameters with each change/stress indices measured in tissues of mussels, could reinforce the use of PSH as a potent biomarker.  相似文献   

11.
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   

12.
Certain specific aspects of cellular structure-linked functions can be used as rapid and sensitive indicators of cellular responses to environmental stimuli such as chemical contaminants.1 It is possible to observe structural-functional alterations in lysosomal membrane stability in the cells of some marine organisms at an early stage of such a response to cell injury,1,2 thus providing an early-warning signal of a potentially deleterious environmental situation. In order to further investigate lysosomal membrane disturbances, mechanisms of injury and capacity for cellular regeneration, the marine snail Littorina littorea was exposed to phenanthrene, which was used as an environmentally widespread and representative polynuclear aromatic hydrocarbon. Lysosomal membrane stability was measured using cytochemical determination of hydrolase latency,2 and lysosomal lipofuscin was measured as a possible indicator of enhanced lipid peroxidative damage.3  相似文献   

13.
Seven stations were established in the Quanzhou Bay (24.73°-24.96°N, 118.50°-118.70°E) in China on three cruises to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and the numbers of PAH-degrading bacteria in surface sediments. Assessing the biodegradation poten- tial of indigenous microorganisms by measuring the respiratory intensity with the addition of PAHs in sediment samples was also one of the aims of this study. The results show that the total PAH concentrations of the sedimen...  相似文献   

14.
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   

15.
Every day new extraordinary properties of nanoparticles (a billionth of a meter) are discovered and worldwide millions are invested into nanotechnology and nanomaterials. Risks to marine organisms are still not fully understood and biomarkers to detect health effects are not implemented, yet. We used the filter feeding blue mussel as a model to analyse uptake and effects of nanoparticles from glass wool, a new absorbent material suggested for use in floating oil spill barriers. In both, gills and hepatopancreas we analysed uptake of nanomaterials by transmission electronmicroscopy (TEM) in unstained ultrathin sections over a period of up to 16 days. Lysosomal stability and lipofuscin content as general indicators of cellular pathology and oxidative stress were also measured. As portals of uptake, diffusion and endocytosis were identified resulting in nanoparticle accumulation in endocytotic vesicles, lysosomes, mitochondria and nuclei. Dramatic decrease of lysosomal membrane stability occurred after 12h of exposure. Lysosomal damage was followed by excessive lipofuscin accumulation indicative of severe oxidative stress. Increased phagocytosis by granulocytes, autophagy and finally apoptosis of epithelial cells of gills and primary and secondary digestive tubules epithelial cells indicated progressive cell death. These pathological responses are regarded as general indices of toxic cell injury and oxidative stress. By the combinational use of biomakers with the ultrastructural localisation of nanoparticle deposition, final evidence of cause-effect relationships is delivered.  相似文献   

16.
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   

17.
The purpose of these studies was to evaluate if there were relationships between lysosomal destabilization or glutathione concentrations and gamete viability of oysters, Crassostrea virginica. Oysters were collected from field sites during the peak spawning period (May-June) during 2001 and 2002. Lysosomal destabilization rates and glutathione concentrations of hepatopancreas tissues (e.g. digestive gland) were determined. Eggs and sperm from the same adults were also used to conduct embryo development assays with reference seawater collected from a clean site, site water, and also a range of Cd concentrations (the Cd exposures were used to determine if there were differences in susceptibility to pollutants). Baseline embryo development success (e.g. percent normal development when the assays were conducted with reference seawater or site water) was related to lysosomal destabilization, but not glutathione status. However, the susceptibility of embryos to metal toxicity was related to glutathione status, i.e., sensitivity to Cd exposures increased with decreasing glutathione levels. These studies support the hypotheses that there are linkages between embryo development success and susceptibility to pollutant stress and cellular biomarker responses. These kinds of effects on reproductive success could lead to subtle but significant long-term effects on recruitment and viability of oyster populations.  相似文献   

18.
夏季珠江口水体中多环芳烃的分布、组成及来源   总被引：2，自引：0，他引：2  
利用1999年7月对珠江口海域的调查资料,对该区表层海水中优控多环芳烃的分布、组成及来源进行了分析和讨论,结果表明:(1)夏季珠江口海域表层海水中14种溶解态多环芳烃[苊、芴、菲、蒽、荧蒽、芘、苯并(a)蒽、艹屈、苯并(b)荧蒽、苯并(k)荧蒽、苯并(a)芘、二苯并(a,h)蒽、苯并(g,h,i)艹北、茚并(1,2,3-cd)艹比]的质量浓度为63.8~171.7 ng/L,且沿着冲淡水流向呈降低趋势;(2)颗粒态中15种多环芳烃[萘、苊、芴、菲、蒽、荧蒽、芘、苯并(a)蒽、艹屈、苯并(b)荧蒽、苯并(k)荧蒽、苯并(a)芘、二苯并(a,h)蒽、苯并(g,h,i)艹北、茚并(1,2,3-cd)艹比]的质量浓度为60.7~186.7 ng/L,其分布与水体载沙量及悬浮颗粒物的性质、粒径有关,具有从河口内向外海降低的分布特征;(3)多环芳烃组成和特征参数比值的分析表明,珠江口海域高温裂解来源的多环芳烃在伶仃洋海区输入最多,且主要为人类活动中煤燃烧排放的,而在香港岛周围海区的输入则相对较少,且主要为油燃烧排放的;(4)与法国塞纳河及长江口等河口相比,珠江三角洲海域水体中存在高菲含量排放源。  相似文献   

19.
Female and male individuals of the same species often differ with respect to their susceptibility to toxicant stress. In the present study, sea urchins (Psammechinus miliaris) of both sexes were exposed to high (150 μg L?1) and environmentally relevant (5 μg L?1) concentrations of phenanthrene over 10 days. While food intake was significantly decreased following exposure to 150 μg L?1 phenanthrene, histological indices (lipofuscin accumulation, fibrosis, oocyte atresia), energetic status (energy charge, sum adenylates, AMP/ATP ratio) as well as ascorbate levels in the gonads showed either little or no effect upon phenanthrene exposure. However, most parameters (vitamin C, energy charge, sum adenylates, AMP/ATP ratio, ATP and ADP concentrations, lipofuscin content, fibrosis) significantly differed between male and female animals. This study illustrates the difficulties to identify toxic injury in reproductive tissue as it may be superimposed by gametogenesis and spawning of gametes.  相似文献   

20.
Immune inhibition in marine mussels by polycyclic aromatic hydrocarbons   总被引：2，自引：0，他引：2  
Polycyclic aromatic pollutants produced by a range of industrial processes and the combustion of fossil fuels. They eventually enter the marine environment, and are bioaccumulated in the tissues of sessile, filter-feeding bivalves, causing a variety of sublethal effects. Few studies, however, have examined immune inhibition in molluscs by these xenobiotics. Here, the immunotoxic effects of PAHs were investigated in marine mussels (Mytilus edulis) by means of in vivo exposure experiments. Animals were exposed to a PAH cocktail of anthracene, fluoranthene and phenanthrene for 2 or 4 weeks. The haemolymph was then extracted, and phagocytosis and lysosomal neutral red retention assays performed to examine the effects of PAHs on particle uptake by haemocytes and lysosome integrity, respectively. PAHs were found to inhibit phagocytosis and damage lysosomes. It is hypothesized that PAHs exert their toxicity directly on the lysosomes. A possible consequence of such lysosomal damage will be immune impairment in mussels leading to reduced resistance to infectious diseases.  相似文献   

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