A histopathological survey of shore crab (Carcinus maenas) and brown shrimp (Crangon crangon) from six estuaries in the United Kingdom

Aluminum exposure alters the pedal mucous secretions of the chocolate-band snail, Eobania vermiculata (Gastropoda: Helicidae)

Aluminum (Al) is used in everyday life and present in food drugs, packaging, industry, and agriculture. Although it is the most common metal in the Earth crust, a correlation has been demonstrated between its presence and various pathologies, even serious ones, especially of a neurological type. However, there is a histological gap regarding the role Al can have in contact with the covering and secreting epithelia. The alterations of the ventral and dorsal foot mucocytes and their secretions of the snail Eobania vermiculata caused by Al were investigated in situ by histochemical and lectin-histochemical techniques. Administration to different experimental groups took place for 3 and 9 days with 50 and 200 μM of AlCl3 . Several types of mucocytes were detected with a prevalent secretion of acid glycans in the foot of E. vermiculata. Sulfated glycans prevail in the dorsal region, with one type showing only fucosylated residues and another also having galactosaminylated and glycosaminylated residues. Carboxylated glycans prevail in the ventral region, with presence of galactosaminylated, glycosaminylated, and fucosylated residuals in both cells. Snails treated presented a general decrease of mucin amount in the secreting cells and affected the mucus composition. These changes could alter the rheological and functional properties of the mucus with possible implications for the health of the treated animals. RESEARCH HIGHLIGHTS: Snails were fed with Al-contaminated lettuce at different concentrations. In the foot mucocytes produced mucus with prevailing acidic glycans. In the treated resulted a reduction in the amount of mucus and an alteration of glycan composition.

Redox-active metals and oxidative stress-mediated myopathies in Callinectes amnicola, blue crab populations from impacted sites of the Lagos Lagoon: inferences for adverse ecological outcomes

While oxidative stress pathways are associated with a wide variety of tissue pathologies, its applications for evaluating and discerning ecological risks are limited. This study seeks to associate trends of lipid peroxidation and oxidative stress to risks of muscle pathologies in blue crabs inhabiting regions of the Lagos Lagoon. Crab samples (n = 520) were selected from pollution-impacted sites of the lagoon at Iddo, Ajah, Okobaba, Makoko, and the mid-lagoon area (control site). Antioxidant enzyme capacity, i.e., superoxide dismutase, catalase, glutathione peroxidase (GPx), and glutathione-S-transferase, and lipid peroxidation were evaluated in the muscle tissue of the blue crabs. The study findings showed distinct patterns of metal uptake in muscle, with redox-active metals (Cu and Zn) and redox-inactive metals (Pb and Cd) exhibiting site-specific differences. Additionally, there were changes in antioxidant modulation, lipid peroxidation, and the presence of associated myopathies. Blue crabs from sites (Makoko and Ajah) with greater uptake of redox-active metals (Cu and Zn) in muscle tissue showed higher trends of lipid peroxidation and the most prevalence of severe regression-type myopathies. Sites with lower uptake of redox-active metals showed the predominance of circulatory-type myopathies. This study also provides evidence of severe necrosis and myositis associated with digenean parasite cysts in crab muscle. Pathological evidence of severe skeletal muscle deterioration in the presence of greater lipid peroxidation could have implications for motor-neuron activity and reduced force-generating capacity necessary for adaptive responses in the wild. We conclude that elevated uptake of redox metals could aggravate the onset of myopathies in wild populations.

Salinity and temperature affect the symbiont profile and host condition of Florida USA blue crabs Callinectes sapidus

Subtropical Florida blue crabs, Callinectes sapidus, exhibit differing life history traits compared to their temperate counterparts, likely influencing symbiont infection dynamics. Little information exists for Florida C. sapidus symbiont profiles, their distribution among various habitats, and influence on crab condition. Using histopathology, genomics, and transmission electron microscopy, we describe the first symbiont profiles for Florida C. sapidus occupying freshwater to marine habitats. Twelve symbiont groups were identified from 409 crabs including ciliophorans, digenean, microsporidian, Haplosporidia, Hematodinium sp., Nematoda, filamentous bacteria, gregarine, Callinectes sapidus nudivirus, Octolasmis sp., Cambarincola sp., and putative microcell. Overall, 78% of C. sapidus were documented with one or more symbiont groups demonstrating high infection rates in wild populations. Environmental variables water temperature and salinity explained 48% of the variation in symbiont groups among Florida habitats, and salinity was positively correlated with C. sapidus symbiont diversity. This suggests freshwater C. sapidus possess fewer symbionts and represent healthier individuals compared to saltwater populations. Crab condition was examined using the reflex action mortality predictor (RAMP) to determine if reflex impairment could be linked to symbiont prevalence. Symbionts were found positively correlated with crab condition, and impaired crabs were more likely to host symbionts, demonstrating symbiont inclusion may boost predictive ability of the RAMP application. The microsporidian symbiont group had a particularly strong effect on C. sapidus reflex response, and impairment was on average 1.57 times higher compared to all other symbiont groups. Our findings demonstrate the importance of considering full symbiont profiles and their associations with a spatially and temporally variable environment to fully assess C. sapidus population health.

Effect of the Insecticide Chlorpyrifos on Behavioral and Metabolic Aspects of the Spider Polybetes pythagoricus

The toxicity of pesticides to organisms depends on the total amount of chemical exposure. Toxicity can be minimized if the organism recognizes the pesticide and alters its behavior. Furthermore, the physical barrier of cuticular hydrocarbons can prevent the entrance of the pesticide into the organism. Finally, if the pesticide enters the body, the organism experiences physiological changes favoring detoxification and the maintenance of homeostasis. We analyzed the behavioral and metabolic response of the spider Polybetes pythagoricus at different times of exposure to the organophosphate pesticide chlorpyrifos. First we observed that the individuals are capable of recognizing and avoiding surfaces treated with pesticides based on a behavioral analysis. Subsequently, we characterized cuticular hydrocarbons as a possible barrier against pesticides. Then we observed that the pesticide provoked histological damage, mainly at the level of the midgut diverticula. Finally, we analyzed the activity of several of the spider's enzymes linked to oxidative stress after exposure to chlorpyrifos for different lengths of time (6, 24, and 48 h). We observed that catalase activity was high at the start, whereas the activity of superoxide dismutase and glutathione S-transferase changed significantly at 48 h. Lipid peroxidation became high at 6 h, but decreased at 48 h. In conclusion, although P. pythagoricus can avoid contact with chlorpyrifos, this pesticide causes activation of the antioxidant system when it enters the body. Our results make a significant contribution to the ecotoxicology of spiders. Environ Toxicol Chem 2023;00:1-16. © 2023 SETAC.

Identification and Full Characterisation of Two Novel Crustacean Infecting Members of the Family Nudiviridae Provides Support for Two Subfamilies

Multiple enveloped viruses with rod-shaped nucleocapsids have been described, infecting the epithelial cell nuclei within the hepatopancreas tubules of crustaceans. These bacilliform viruses share the ultrastructural characteristics of nudiviruses, a specific clade of viruses infecting arthropods. Using histology, electron microscopy and high throughput sequencing, we characterise two further bacilliform viruses from aquatic hosts, the brown shrimp (Crangon crangon) and the European shore crab (Carcinus maenas). We assembled the full double stranded, circular DNA genome sequences of these viruses (~113 and 132 kbp, respectively). Comparative genomics and phylogenetic analyses confirm that both belong within the family Nudiviridae but in separate clades representing nudiviruses found in freshwater and marine environments. We show that the three thymidine kinase (tk) genes present in all sequenced nudivirus genomes, thus far, were absent in the Crangon crangon nudivirus, suggesting there are twenty-eight core genes shared by all nudiviruses. Furthermore, the phylogenetic data no longer support the subdivision of the family Nudiviridae into four genera (Alphanudivirus to Deltanudivirus), as recently adopted by the International Committee on Taxonomy of Viruses (ICTV), but rather shows two main branches of the family that are further subdivided. Our data support a recent proposal to create two subfamilies within the family Nudiviridae, each subdivided into several genera.

Symbionts of invasive and native crabs, in Argentina: The most recently invaded area on the Southwestern Atlantic coastline

Biological invasions have the capacity to introduce non-native parasites. This study aimed to determine whether the invasive green crab population, Carcinus spp., on the Southwestern Atlantic coast of Argentina harbours any symbionts, and whether these may spillover or spillback between native crabs, Cyrtograpsus altimanus and C. angulatus. Macroscopy, histology, and molecular analyses of some parasites were used to describe and compare their diversity across the three species of crab. We also evaluated the susceptibility of invasive Carcinus spp. to a native digenean, Maritrema madrynense, via experimental infections (exposure and cohabitation). Our results revealed that the green crab pathobiome included similar symbiotic groups to native crabs. This included putative viral, bacterial, and protozoan parasites. Haplosporidium-like observations were recorded in all crab species, and a single green crab was found to be parasitized by an Agmasoma-like microsporidium. Metagenomic analysis of one individual revealed additional symbiotic diversity (46 bacteria, 5 eukaryotic species). The green crabs were infected by more microparasite taxa than the native crabs (5:3). Wild populations of Carcinus spp. were free of metazoan parasites and are shown not to be susceptible to M. madryense under experimental conditions. Our results suggest a reduction/escape of macroparasites (trematode Maritrema madrynense; acanthocephalan Profilicollis chasmagnathi) in invasive Carcinus spp. compared to their native competitors.

A Comprehensive Review on Crustaceans' Immune System With a Focus on Freshwater Crayfish in Relation to Crayfish Plague Disease

Freshwater crayfish immunity has received great attention due to the need for urgent conservation. This concern has increased the understanding of the cellular and humoral defense systems, although the regulatory mechanisms involved in these processes need updating. There are, however, aspects of the immune response that require clarification and integration. The particular issues addressed in this review include an overall description of the oomycete Aphanomyces astaci, the causative agent of the pandemic plague disease, which affects freshwater crayfish, and an overview of crustaceans' immunity with a focus on freshwater crayfish. It includes a classification system of hemocyte sub-types, the molecular factors involved in hematopoiesis and the differential role of the hemocyte subpopulations in cell-mediated responses, including hemocyte infiltration, inflammation, encapsulation and the link with the extracellular trap cell death pathway (ETosis). In addition, other topics discussed include the identity and functions of hyaline cells, the generation of neoplasia, and the emerging topic of the role of sessile hemocytes in peripheral immunity. Finally, attention is paid to the molecular execution of the immune response, from recognition by the pattern recognition receptors (PRRs), the role of the signaling network in propagating and maintaining the immune signals, to the effector elements such as the putative function of the Down syndrome adhesion molecules (Dscam) in innate immune memory.

Invasive Non-Native Crustacean Symbionts: Diversity and Impact

Invasive non-native species (INNS) pose a risk as vectors of parasitic organisms (Invasive Parasites). Introducing invasive parasites can result in ecological disturbances, leading to biodiversity loss and native species illness/mortality, but occasionally can control INNS limiting their impact. Risks to human health and the economy are also associated with INNS and invasive parasites; however, we understand little about the diversity of symbiotic organisms co-invading alongside INNS. This lack of clarity is an important aspect of the 'One Health' prerogative, which aims to bridge the gap between human, wildlife, and ecosystem health. To explore symbiont diversity associated with the invasive crustacean group (including: crab, lobster, crayfish, shrimp, amphipod, isopod, copepod, barnacle, other) (n = 323) derived from 1054 aquatic invertebrates classed as INNS across databases, we compile literature (year range 1800-2017) from the native and invasive range to provide a cumulative symbiont profile for each species. Our search indicated that 31.2% of INN crustaceans were known to hold at least one symbiont, whereby the remaining 68.8% had no documented symbionts. The symbiont list mostly consisted of helminths (27% of the known diversity) and protists (23% of the known diversity), followed by bacteria (12%) and microsporidians (12%). Carcinus maenas, the globally invasive and extremely well-studied green crab, harboured the greatest number of symbionts (n = 72). Additional screening is imperative to become more informed on invasive symbiont threats. We reveal that few studies provide truly empirical data that connect biodiversity loss with invasive parasites and suggest that dedicated studies on available systems will help to provide vital case studies. Despite the lack of empirical data, co-invasive parasites of invasive invertebrates appear capable of lowering local biodiversity, especially by causing behavioural change and mortality in native species. Alternatively, several invasive parasites appear to protect ecosystems by controlling the impact and population size of their invasive host. We provide a protocol that could be followed to explore symbiont diversity in invasive groups as part of our case studies. The consequence of limited parasite screening of INNS, in addition to the impacts invasive parasites impart on local ecologies, are explored throughout the review. We conclude in strong support of the 'One Health' prerogative and further identify a need to better explore disease in invasion systems, many of which are accountable for economic, human health and ecological diversity impacts.

Exploration of the virome of the European brown shrimp (Crangon crangon)

Crangon crangon is economically a very important species. Recently, promising culture attempts have been made, but a major problem is the uncontrollable mortality during the grow-out phase. As of yet, the life cycle of C. crangon is not closed in captivity so wild-caught individuals are used for further rearing. Therefore, it is important to investigate the virome of C. crangon both in wild-caught animals as in cultured animals. In recent years, next-generation-sequencing (NGS) technologies have been very important in the unravelling of the virome of a wide range of environments and matrices, such as soil, sea, potable water, but also of a wide range of animal species. This will be the first report of a virome study in C. crangon using NGS in combination with the NetoVIR protocol. The near complete genomes of 16 novel viruses were described, most of which were rather distantly related to unclassified viruses or viruses belonging to the Picornavirales, Bunyavirales Nudiviridae, Parvoviridae, Flaviviridae, Hepeviridae, Tombusviridae, Narnaviridae, Nodaviridae, Sobemovirus. A difference in virome composition was observed between muscle and hepatopancreatic tissue, suggesting a distinct tissue tropism of several of these viruses. Some differences in the viral composition were noted between the cultured and wild shrimp, which could indicate that in sub-optimal aquaculture conditions some viruses become more abundant. This research showed that a plethora of unknown viruses is present in C. crangon and that more research is needed to determine which virus is potentially dangerous for the culture of C. crangon.

First report of an idiopathic partial tail myonecrosis in European brown shrimp Crangon crangon caught in the North Sea

The European brown shrimp Crangon crangon is an abundant and commercially important species in the North Sea. Currently, there is interest in landing live shrimp to provide fresh animals for a growing market in live brown shrimp. During 4 survival studies between 2014 and 2016, shrimp were collected from commercial trawlers and maintained alive in off-shore facilities. From Day 1 onwards, a minority of shrimp (~2.24%) developed a white discoloration of the abdominal muscles and a depigmentation of the distal part of the abdomen, along with paralysis of the affected tissues and appendages. As the symptoms progressed, a circumferential blackish delineation appeared, creating a distinct boundary between healthy and necrotic tissue. Affected shrimp survived up to 3 wk, although in several animals the distal part of the tail was completely lost. Histological and electron microscopical examination confirmed the myonecrosis. A secondary bacterial invasion of the necrotic muscle was observed in some animals. RT-PCR for infectious myonecrosis virus was negative. The condition appears not to be contagious, based on the feeding of healthy shrimp with necrotic tissue of affected shrimp. Based on these observations, a mechanical cause inflicted during the catching process is proposed.

Prevalence and histopathology of the parasitic barnacle, Sacculina carcini in shore crabs, Carcinus maenas

Sacculina carcini is a common parasite of the European shore crab, Carcinus maenas. Following successful penetration of the host, numerous rootlets are formed that permeate through the hosts' tissues. Ultimately, these form an externa that houses the developing nauplii larvae of the parasite. Most studies have quantified levels of infection by counting the presence of reproductive externae and their breakdown structures, called scars. However, the diagnosis of the disease based only on external features may lead to underreporting the prevalence of the parasite. In the current study, we examined the presence and severity of S. carcini in C. maenas (n = 221) in the Prince of Wales Dock, South Wales, U.K. using a range of diagnostic approaches to give an accurate representation of temporal dynamics of infection. Parasitized crabs were found with a mean prevalence of 24% as determined by histological examination of the hepatopancreas. However, the prevalence of S. carcini based on the presence of externae and scars was only 6.3% and 1.8%, respectively. Overall, parasitism was associated with smaller crabs, crabs later in the moulting cycle that were orange in colour (as opposed to green or yellow), and those with a higher number of bacteria in the haemolymph. Interestingly, only 7.5% of infected crabs showed evidence of distinct host (cellular) response to the presence of rootlets in the hepatopancreas.

Biomphalaria alexandrina: a model organism for assessing the endocrine disrupting effect of 17β-estradiol

A wide range of endocrine disruptor compounds are routinely discharged to the ecosystem. Water contaminated with these compounds has a potential effect on the reproductive physiology of aquatic organisms as well as humans. In the present study, we tested the effect of the steroid estrogen, 17β-estradiol, on Biomphalaria alexandrina, a snail species that is widely distributed in Egypt and that acts as an intermediate host for the human blood fluke, Schistosoma mansoni. The effects of exposure to 0.3 mg/L and 1 mg/L 17β-estradiol on fecundity (M_X) and reproductive rate (R₀) of B. alexandrina were recorded. In addition, levels of steroid sex hormones and antioxidants in the hemolymph and ovotestis (OT) of exposed snails were measured. Histopathological changes in the OT of B. alexandrina were also investigated. Exposure to 0.3 mg/L and 1 mg/L 17β-estradiol caused a significant increase in the number of egg masses per snail after 3 weeks and 1 week of exposure for the two tested concentrations compared with unexposed controls. An increase in the levels of progesterone hormone was recorded in the hemolymph of exposed snails in comparison with unexposed controls. Additionally, levels of the antioxidant enzyme glutathione (GSH) were increased in the hemolymph and OT tissues of snails after 2 and 4 weeks of exposure. Histopathological sections in the OT revealed an increase in the oocyte and a decrease in the sperm densities after 2 weeks and this effect was restored to normal conditions after 4 weeks of exposure to both tested concentrations. The current results indicate that B. alexandrina is sensitive to 17β-estradiol and can therefore be used as bioindicator and model organism for the assessment of water pollution with endocrine disruptor compounds.

Green crab Carcinus maenas symbiont profiles along a North Atlantic invasion route

The green crab Carcinus maenas is an invader on the Atlantic coast of Canada and the USA. In these locations, crab populations have facilitated the development of a legal fishery in which C. maenas is caught and sold, mainly for use as bait to capture economically important crustaceans such as American lobster Homarus americanus. The paucity of knowledge on the symbionts of invasive C. maenas in Canada and their potential for transfer to lobsters poses a potential risk of unintended transmission. We carried out a histological survey for symbionts of C. maenas from their native range in Northern Europe (in the UK and Faroe Islands), and invasive range in Atlantic Canada. In total, 19 separate symbiotic associations were identified from C. maenas collected from 27 sites. These included metazoan parasites (nematodes, Profilicollis botulus, Sacculina carcini, Microphallidae, ectoparasitic crustaceans), microbial eukaryotes (ciliates, Hematodinium sp., Haplosporidium littoralis, Ameson pulvis, Parahepatospora carcini, gregarines, amoebae), bacteria (Rickettsia-like organism, milky disease), and viral pathogens (parvo-like virus, herpes-like virus, iridovirus, Carcinus maenas bacilliform virus and a haemocyte-infecting rod-shaped virus). Hematodinium sp. were not observed in the Canadian population; however, parasites such as Trematoda and Acanthocephala were present in all countries despite their complex, multi-species lifecycles. Some pathogens may pose a risk of transmission to other decapods and native fauna via the use of this host in the bait industry, such as the discovery of a virus resembling the previously described white spot syndrome virus (WSSV), B-virus and 'rod-shaped virus' (RV-CM) and amoebae, which have previously been found to cause disease in aquaculture (e.g. Salmo salar) and fisheries species (e.g. H. americanus).

Development and application of a duplex PCR assay for detection of Crangon crangon bacilliform virus in populations of European brown shrimp (Crangon crangon)

Crangon crangon bacilliform virus (CcBV) was first discovered in 2004 in European brown shrimp (Crangon crangon) caught along the English coast. This study describes a duplex PCR assay developed for the detection of CcBV, based on amplification of the lef-8 gene (211 bp) of CcBV and the E75 gene (105 bp) of C. crangon as an internal amplification control. The lef-8 and E75 primer pairs were designed based on preliminary genome sequencing information of the virus and transcriptomic data available for C. crangon, respectively. Sequencing of the resulting amplicons confirmed the specificity of this PCR assay and sequence analysis of the lef-8 fragment revealed amino acid identity percentages ranging between 31 and 42% with members of the Nudiviridae, proposing that CcBV may reside within this family. Finally, the duplex PCR assay was applied to samples of C. crangon hepatopancreas tissue collected along the Belgian coast to screen for the presence of CcBV. The prevalence of CcBV averaged 87%, which is comparable to previous reports of high prevalence, based upon histological analysis, in shrimp collected along the English coast. Development of a specific and sensitive PCR assay to detect CcBV will provide a useful tool for future aquaculture and research programs involving C. crangon.

Metal uptake, oxidative stress and histopathological alterations in gills and hepatopancreas of Callinectes amnicola exposed to industrial effluent

Metal uptake by biota due to elevated environmental concentrations elicits oxidative stress and could lead to pathological outcomes. The relationship between the histopathological profile of hepatopancreas and gills and altered biochemical features (antioxidant enzymes i.e. GSH, GPx, CAT, SOD, lipid peroxidation (MDA) and serum protein) in the blue crab, Callinectes amnicola from contaminated parts of the Lagos Lagoon was investigated. Monthly crab, sediment and surface water samples were taken from effluent receiving areas of the Lagos lagoon i.e. Makoko, Okobaba, Iddo, Ikoyi and Mid-lagoon (control site) over an 18-month period and analyzed for metal levels (Pb, Cd, Zn and Cu). Significantly higher levels of GPx and lower levels of Pb, Zn and Cu was recorded in gills and hepatopancreas of crabs from the mid-lagoon compared to crabs from other sites. Reaction patterns of gills across the different sites of the lagoon included regressive (ranging from epithelial lifting, disruption of pilaster cells, detached cuticle to focal necrosis) and circulatory disruptions (oedema); increased activity of GSH and GPx in gills were positively correlated with lesions of lower importance factor. Reaction patterns in hepatopancreas were more regressive including vacuolation/infiltration of fatty lobules, necrosis, granuloma, disintegrated lumen, atrophied tubules and loss of lobular hepatocyte structure; increased activity of GSH, GPx and CAT were positively correlated with lesions of low importance factor in the hepatopancreas. Findings show that lesions in both gills and hepatopancreas of the blue crab could be associated with uptake of metals, depleted antioxidant activity and incidence of lipid peroxidation in tissue.

Parasites, pathogens and commensals in the "low-impact" non-native amphipod host Gammarus roeselii

Background

Whilst vastly understudied, pathogens of non-native species (NNS) are increasingly recognised as important threats to native wildlife. This study builds upon recent recommendations for improved screening for pathogens in NNS by focusing on populations of Gammarus roeselii in Chojna, north-western Poland. At this location, and in other parts of continental Europe, G. roeselii is considered a well-established and relatively ‘low-impact’ invader, with little understanding about its underlying pathogen profile and even less on potential spill-over of these pathogens to native species.

Results

Using a combination of histological, ultrastructural and phylogenetic approaches, we define a pathogen profile for non-native populations of G. roeselii in Poland. This profile comprised acanthocephalans (Polymorphus minutus Goese, 1782 and Pomphorhynchus sp.), digenean trematodes, commensal rotifers, commensal and parasitic ciliated protists, gregarines, microsporidia, a putative rickettsia-like organism, filamentous bacteria and two viral pathogens, the majority of which are previously unknown to science. To demonstrate potential for such pathogenic risks to be characterised from a taxonomic perspective, one of the pathogens, a novel microsporidian, is described based upon its pathology, developmental cycle and SSU rRNA gene phylogeny. The novel microsporidian Cucumispora roeselii n. sp. displayed closest morphological and phylogenetic similarity to two previously described taxa, Cucumispora dikerogammari (Ovcharenko & Kurandina, 1987), and Cucumispora ornata Bojko, Dunn, Stebbing, Ross, Kerr & Stentiford, 2015.

Conclusions

In addition to our discovery extending the host range for the genus Cucumispora Ovcharenko, Bacela, Wilkinson, Ironside, Rigaud & Wattier, 2010 outside of the amphipod host genus Dikerogammarus Stebbing, we reveal significant potential for the co-transfer of (previously unknown) pathogens alongside this host when invading novel locations. This study highlights the importance of pre-invasion screening of low-impact NNS and, provides a means to document and potentially mitigate the additional risks posed by previously unknown pathogens.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2108-6) contains supplementary material, which is available to authorized users.

Biological response of earthworm, Eisenia fetida, to five neonicotinoid insecticides

Earthworms (Eisenia fetida) are one of the most abundant terrestrial species, and play an important role in maintaining the ecological function of soil. Neonicotinoids are some of the most widely used insecticides applied to crops. Studies on the effect of neonicotinoids on E. fetida are limited. In the present work, we evaluated the effects of five neonicotinoid insecticides on reproduction, cellulase activity and the tissues of E. fetida. The results showed that, the LC50 of imidacloprid, acetamiprid, nitenpyram, clothianidin and thiacloprid was 3.05, 2.69, 4.34, 0.93 and 2.68mgkg(-1), respectively. They also could seriously affect the reproduction of E. fetida, reducing the fecundity by 84.0%, 39.5%, 54.3%, 45.7% and 39.5% at the sub-lethal concentrations of 2.0, 1.5, 0.80, 2.0 and 1.5mgkg(-1), respectively. The cellulase activity of E. fetida was most sensitive to clothianidin. Significant disruption of the epidermal and midgut tissue was observed after 14d exposure. In summary, we demonstrate that imidacloprid, acetamiprid, nitenpyram, clothianidin and thiacloprid have high toxic to earthworm, and can significantly inhibited fecundity and cellulase activity of E. fetida, and they also damage the epidermal and midgut cells of earthworm.

Assessing the effects of trematode infection on invasive green crabs in eastern north america

A common signature of marine invasions worldwide is a significant loss of parasites (= parasite escape) in non-native host populations, which may confer a release from some of the harmful effects of parasitism (e.g., castration, energy extraction, immune activation, behavioral manipulation) and possibly enhance the success of non-indigenous species. In eastern North America, the notorious invader Carcinus maenas (European green crab) has escaped more than two-thirds its native parasite load. However, one of its parasites, a trematode (Microphallus similis), can be highly prevalent in the non-native region; yet little is known about its potential impacts. We employed a series of laboratory experiments to determine whether and how M. similis infection intensity influences C. maenas, focusing on physiological assays of body mass index, energy storage, and immune activation, as well as behavioral analyses of foraging, shelter utilization, and conspicuousness. We found little evidence for enduring physiological or behavioral impacts four weeks after experimental infection, with the exception of mussel handling time which positively correlated with cyst intensity. However, we did find evidence for a short-term effect of M. similis infection during early stages of infection (soon after cercarial penetration) via a significant drop in circulating immune cells, and a significant increase in the crabs' righting response time. Considering M. similis is the only common parasite infecting C. maenas in eastern North America, our results for minimal lasting effects of the trematode on the crab's physiology and behavior may help explain the crab's continued prominence as a strong predator and competitor in the region.

Heavy metals and hydrocarbon concentrations in water, sediments and tissue of Cyclope neritea from two sites in Suez Canal, Egypt and histopathological effects

Heavy metals and hydrocarbons are of the most common marine pollutants around the world. The present study aimed to assess the concentration of petroleum hydrocarbons and heavy metals in tissues of the snail cyclope neritea, water and sediments from two sites of the study area (Temsah lake and Suez canal) represent polluted and unpolluted sites respectively. The results showed that, the levels of the heavy metals (Pb, Cd, Co, Mg and Zn) in the polluted area have reached harmful limits recorded globally. Lead in water, sediment and tissue of the snail reached to 0.95 ppm, 4.54 ppm and 7.93 ppm respectively. Cadmium reached 0.31 ppm, 1.15 ppm and 3.08 ppm in the corresponding samples. Cobalt was not detected in water, but it reached 1.42 ppm and 10.36 ppm in the sediment and snails tissue respectively. Magnesium in water, sediment and tissue of the snail reached 3.73 ppm, 9.44 ppm and12.6 ppm respectively. Zinc reached 0.11 ppm, 3.89 ppm and 12.60ppm in the corresponding samples. Meanwhile, hydrocarbons in the polluted area (site1) reached 110.10 μg/L, 980.15 μg/g and 228.00 μg/g in water sediment and digestive gland tissues of the snails respectively. Whereas, hydrocarbons in the unpolluted area (site2) were estimated as 14.20 μg/L, 55.60 μg/g and 22.66 μg/g in water, sediment and tissue of the snails respectively. The combination of histopathological image with monitoring of the metal level in the digestive gland of the present snail provides an important tool for early detection of impending environmental problems and potential public health issues. Petroleum hydrocarbons are toxic to the marine fauna when present above certain limit in the marine water. The major detoxification organ in molluscs is the digestive gland, which has been used as a bioindicator organ for toxicity assessment. The effect of high crude oil on the digestive gland tubules of exposed snails when examined microscopically reveals a series of histological changes which indicates that the cellular compensatory mechanism is activated by hydrocarbons. These changes include vacuolation and presence of pyknotic nuclei.

The crab Carcinus maenas as a suitable experimental model in ecotoxicology

Aquatic ecotoxicology broadly focuses on how aquatic organisms interact with pollutants in their environment in order to determine environmental hazard and potential risks to humans. Research has produced increasing evidence on the pivotal role of aquatic invertebrates in the assessment of the impact of pollutants on the environment. Its potential use to replace fish bioassays, which offers ethical advantages, has already been widely studied. Nevertheless, the selection of adequate invertebrate experimental models, appropriate experimental designs and bioassays, as well as the control of potential confounding factors in toxicity testing are of major importance to obtain scientifically valid results. Therefore, the present study reviews more than four decades of published research papers in which the Green crab Carcinus maenas was used as an experimental test organism. In general, the surveyed literature indicates that C. maenas is sensitive to a wide range of aquatic pollutants and that its biological responses are linked to exposure concentrations or doses. Current scientific knowledge regarding the biology and ecology of C. maenas and the extensive studies on toxicology found for the present review recognise the Green crab as a reliable estuarine/marine model for routine testing in ecotoxicology research and environmental quality assessment, especially in what concerns the application of the biomarker approach. Data gathered provide valuable information for the selection of adequate and trustworthy bioassays to be used in C. maenas toxicity testing. Since the final expression of high quality testing is a reliable outcome, the present review recommends gender, size and morphotype separation in C. maenas experimental designs and data evaluation. Moreover, the organisms' nutritional status should be taken into account, especially in long-term studies. Studies should also consider the crabs' resilience when facing historical and concurrent contamination. Finally, experimental temperature and salinity should be harmonised so as to obtain reliable comparisons between different studies. Concerning future reaserch areas, data gathered in the present review reveals that in vitro assays derived from C. maenas are still lacking. Also, a complete C. maenas genome sequencing programme will be essencial for cutting-edge reseach.

Histopathological survey of potential biomarkers for the assessment of contaminant related biological effects in species of fish and shellfish collected from Kuwait Bay, Arabian Gulf

The marine environment in Kuwait is dominated by Kuwait Bay, a shallow, depositional habitat vital for the breeding and propagation of marine organisms. The bay receives effluent inputs from industrial centres, ports, sewage outflows along with discharges from power and desalination plants. The major classes of pollutant discharged into the bay include petroleum hydrocarbons, metals, nutrients, cooling water and hyper-saline water. Further, the bay has been historically impacted by a deliberate release of oil and contamination with ordnance and shipwrecks during the 1991 Gulf war. With an aim to establish an integrated pollution effects monitoring programme in Kuwait, this paper describes the application of a quality assured approach to conduct a histopathology baseline survey in oriental sole (Synaptura orientalis) and the large-toothed flounder (Pseudorhombus arsius), which are two potential sentinel flatfish species present in the Arabian Gulf. Liver and gonadal histopathology revealed a range of pathologies similar to those previously observed in European and American pollution effects surveys that utilise flatfish (including pathology markers indicative of possible carcinogenesis and endocrine disruption). Further, we extended these studies to invertebrates (Jinga prawn, Metapenaeus affinis and the grooved tiger prawn, Penaeus semisulcatus) found within the Arabian Gulf. Such baseline data is essential before attempts are made to develop integrated monitoring programmes that aim to assess the health of fish and shellfish in relation to chemical contamination.

Overview on the European green crab Carcinus spp. (Portunidae, Decapoda), one of the most famous marine invaders and ecotoxicological models

Green crabs (Carcinus, Portunidae) include two species native to Europe--Carcinus aestuarii (Mediterranean species) and Carcinus maenas (Atlantic species). These small shore crabs (maximal length carapace, approximately 10 cm) show rapid growth, high fecundity, and long planktonic larval stages that facilitate broad dispersion. Carcinus spp. have a high tolerance to fluctuations of environmental factors including oxygen, salinity, temperature, xenobiotic compounds, and others. Shipping of Carcinus spp. over the past centuries has resulted in its invasions of America, Asia, and Australia. Classified as one of the world's 100 worst invaders by the International Union for Conservation of Nature, Carcinus spp. are the most widely distributed intertidal crabs in the world. Their voracious predatory activity makes them strong interactors in local communities, and they are recognized as a model for invasiveness in marine systems as well as a sentinel species in ecotoxicology. This review shows an exhaustive analysis of the literature on the life cycle, diversity, physiological tolerance, genomic investigations, ecotoxicological use, historical invasion, control programs, and putative economical valorization of shore crabs.

Metals bioaccumulation and histopathological biomarkers in Carcinus maenas crab from Bizerta lagoon, Tunisia

Metals concentrations and histolopathological lesions of gills and digestive gland were investigated in Carcinus maenas crabs sampled from Bizerta Lagoon and Kuriat Island (Tunisia) as control site. The concentrations of trace metals varied between tissues, sites and sampling time. The highest levels of the analysed metals in gills and digestive gland were noted in Menzel Bourguiba and Cimentery sites at both sampling times (February and July). The higher metals loads were associated with severe and various tissues alterations in contaminated crabs. We particularly noted in the gills a haemocytic infiltration, distension and enlargement of the lamellae, lifting of lamellar epithelium, necrotic lesions and fusion of lamellae in the most polluted sites (Menzel Bourguiba and Cimentery). Moreover, others pathological alterations were observed in digestive gland of crabs collected from polluted sites and with a severity site dependent. We observed necrotic tubules containing tissue debris in the lumen with more intensity in crabs collected from Cimentery site in both sampling times. The thickened basal laminae and the walling off of the tubules by haemocytes around the thickened basal laminae were more abundant at Menzel Bourguiba than at others sites. The coagulation in the thickened basal laminae was observed only at Cimentery in February. Tissues histopathological lesions were sensitive to discriminate crabs of different sites and demonstrated its usefulness in this biomonitoring study. We recommend the association of histopatholocial lesions to biochemical biomarkers in future biomonitoring studies.

Baseline histopathological survey of a recently invading island population of 'killer shrimp', Dikerogammarus villosus

Dikerogammarus villosus, an invasive amphipod, has recently been detected in UK freshwaters. To assess the potential for pathogen introduction with the invader, a year-long histopathology survey of the D. villosus population inhabiting the initial site of detection (Grafham Water, Cambridgeshire, UK) was conducted. Additional samples were collected from 2 other subsequently identified populations within the UK (Cardiff Bay and Norfolk Broads), and from established populations in France (River Rhine) and Poland (River Vistula). The data revealed a range of pathogens and commensals. Several pathogens occurring within continental populations were not present within the UK populations. Microsporidian parasites and a novel viral pathogen were amongst those not observed in the UK. The absence of these pathogens at UK sites may therefore impart significant survival advantages to D. villosus over native fauna, thereby increasing its success as an invader. The contrast in pathogen profile between UK and continental-invasive populations of D. villosus provides preliminary evidence for so-called 'enemy release' in UK populations of D. villosus and is suggestive of single-point introductions, rather than continual incursion events as previously observed throughout its continental invasive range. This baseline survey provides important data on the pathogen and commensal profile of a high-impact, invasive species early in its invasion history of the UK. It can be utilised to assess potential for temporal pathogen acquisition by non-native invasive aquatic species and to investigate competitive advantages placed upon this invader due to absence of important pathogens experienced within its native range.

Histopathology alterations and lipid peroxidation as biomarkers of hydrocarbon-induced stress in earthworm, Eudrilus eugeniae

This study investigated the biomarker responses of the earthworm, Eudrilus eugeniae, exposed to sublethal concentrations of benzene, toluene and xylene (BTX) for a time span of 28 days. Lipid peroxidation (LPO) and histopathological alterations were examined. Toxicological evaluations of BTX were carried out against E. eugeniae. On the basis of the 96-h LC(50) value, xylene (1.212 mg/kg) was found to be the most toxic followed by toluene (1.335 mg/kg) and benzene (1.896 mg/kg) was the least toxic. The exposure of earthworms to sublethal concentrations (1/10th and 1/100th of 96 h LC(50)) of BTX premixed with the substrate (loamy and humus soil) induced pathological changes in the clitella such as severe lesion, necrosis and dark brown pigments. The result of the lipid peroxidation assay showed a significant increase in oxidative damage with LPO values ranging from 2.58-7.8 nM/g in exposed animals when compared to 0.07 nM/g in the control group. The findings from this study suggest the use of LPO and histopathology as useful biomarkers of exposure for early detection of petroleum related stress in terrestrial ecosystems.

Hematodinium sp. and its bacteria-like endosymbiont in European brown shrimp (Crangon crangon)

BACKGROUND

Parasitic dinoflagellates of the genus Hematodinium are significant pathogens affecting the global decapod crustacean fishery. Despite this, considerable knowledge gaps exist regarding the life history of the pathogen in vivo, and the role of free living life stages in transmission to naïve hosts.

RESULTS

In this study, we describe a novel disease in European brown shrimp (Crangon crangon) caused by infection with a parasitic dinoflagellate of the genus Hematodinium. This is the second example host within the Infraorder Caridea (shrimp) and significantly, the first description within the superfamily Crangonoidea. Based upon analysis of the rRNA gene (SSU) and spacers (ITS1), the parasite in C. crangon is the same as that previously described infecting Nephrops norvegicus and Cancer pagurus from European seas, and to the parasite infecting several other commercially important crab species in the Northern Hemisphere. The parasite is however distinct from the type species, H. perezi, found infecting type hosts (Carcinus maenas and Liocarcinus depurator) from nearby sites within Europe. Despite these similarities, the current study has also described for the first time, a bacteria-like endosymbiont within dinospore stages of the parasite infecting shrimp. The endosymbionts were either contained individually within electron lucent vacuoles within the parasite cell cytoplasm, or remained in direct contact with the parasite cytoplasm or in some cases, the nucleoplasm. In all of these cases, no apparent detrimental effects of colonization were observed within the parasite cell.

CONCLUSIONS

The presence of bacteria-like endosymbionts within dinospore life stages presumes that the relationship between the dinoflagellate and the bacteria is extended beyond the period of liberation of spores from the infected host shrimp. In this context, a potential role of endosymbiosis in the survival of free-living stages of the parasite is possible. The finding offers a further intriguing insight into the life history of this enigmatic pathogen of marine crustacean hosts and highlights a potential for mixotrophy in the parasitic dinoflagellates contained within the genus Hematodinium.

Advances in our understanding of the global diversity and distribution of Hematodinium spp. - significant pathogens of commercially exploited crustaceans

Hematodinium species are parasitic dinoflagellates known to infect a growing number of marine crustacean genera from around the world, many of which support important commercial fisheries. Affected hosts undergo dramatic pathological alterations to their organs, tissues and hemolymph. There are no known control measures for this disease. Economically important wild fished hosts known to be susceptible to Hematodinium spp. include Tanner crabs Chionoecetes bairdi and snow crabs Chionoecetes opilio in the Northeast Pacific and Atlantic Oceans, blue crabs Callinectes sapidus from the Atlantic and Gulf coasts of the United States, and Norway lobsters Nephrops norvegicus and Edible crabs Cancer pagurus from European waters. In recent years, several farmed aquatic crustaceans in China have also been negatively impacted by Hematodinium-associated diseases, likely representing an emerging issue for that expanding industry. Molecular sequence data indicates that there are two species, Hematodinium perezi, and a second species, currently unnamed, infecting hosts from the Northern Hemisphere. Three subtly different H. perezi genotypes have been identified infecting hosts from different geographical locations: the English Channel, the eastern seaboard of the United States and Gulf of Mexico, and eastern China. Genotypic variability between isolates of the Hematodinium sp. infecting hosts from the North Atlantic and North Pacific has also been reported, though it is unclear whether there is any correlation with host or location. Identification of Hematodinium species (and genotypes of H. perezi) is largely dependent upon geographical location, rather than host species. However this is not exclusive, as both Hematodinium species can be found infecting multiple species from same location, as is the case in the English Channel.

Disease will limit future food supply from the global crustacean fishery and aquaculture sectors

Seafood is a highly traded food commodity. Farmed and captured crustaceans contribute a significant proportion with annual production exceeding 10 M metric tonnes with first sale value of $40bn. The sector is dominated by farmed tropical marine shrimp, the fastest growing sector of the global aquaculture industry. It is significant in supporting rural livelihoods and alleviating poverty in producing nations within Asia and Latin America while forming an increasing contribution to aquatic food supply in more developed countries. Nations with marine borders often also support important marine fisheries for crustaceans that are regionally traded as live animals and commodity products. A general separation of net producing and net consuming nations for crustacean seafood has created a truly globalised food industry. Projections for increasing global demand for seafood in the face of level or declining fisheries requires continued expansion and intensification of aquaculture while ensuring best utilisation of captured stocks. Furthermore, continued pressure from consuming nations to ensure safe products for human consumption are being augmented by additional legislative requirements for animals (and their products) to be of low disease status. As a consequence, increasing emphasis is being placed on enforcement of regulations and better governance of the sector; currently this is a challenge in light of a fragmented industry and less stringent regulations associated with animal disease within producer nations. Current estimates predict that up to 40% of tropical shrimp production (>$3bn) is lost annually, mainly due to viral pathogens for which standard preventative measures (e.g. such as vaccination) are not feasible. In light of this problem, new approaches are urgently required to enhance yield by improving broodstock and larval sourcing, promoting best management practices by farmer outreach and supporting cutting-edge research that aims to harness the natural abilities of invertebrates to mitigate assault from pathogens (e.g. the use of RNA interference therapeutics). In terms of fisheries losses associated with disease, key issues are centred on mortality and quality degradation in the post-capture phase, largely due to poor grading and handling by fishers and the industry chain. Occurrence of disease in wild crustaceans is also widely reported, with some indications that climatic changes may be increasing susceptibility to important pathogens (e.g. the parasite Hematodinium). However, despite improvements in field and laboratory diagnostics, defining population-level effects of disease in these fisheries remains elusive. Coordination of disease specialists with fisheries scientists will be required to understand current and future impacts of existing and emergent diseases on wild stocks. Overall, the increasing demand for crustacean seafood in light of these issues signals a clear warning for the future sustainability of this global industry. The linking together of global experts in the culture, capture and trading of crustaceans with pathologists, epidemiologists, ecologists, therapeutics specialists and policy makers in the field of food security will allow these issues to be better identified and addressed.

Biochemical responses of the shore crab (Carcinus maenas) in a eutrophic and metal-contaminated coastal system (Obidos lagoon, Portugal)

A eutrophic and metal-contaminated coastal system (Obidos lagoon, Portugal) was monitored combining water/sediment quality parameters and Carcinus maenas biomarkers (accumulated metals, oxidative stress and biotransformation responses). Two confined branches (Barrosa and Bom-Sucesso) were surveyed and compared with a reference area. Both crab genders from Barrosa exhibited activation of hepatopancreas CAT, GPx and GST, pointing out this area as the major impacted in the lagoon. Females captured at Barrosa were more vulnerable to peroxidative damage while only males showed decreased EROD activity, reinforcing gender specificities. In general, responses were not directly attributed to metals in hepatopancreas, as supported by Principal Component Analysis (PCA). However, higher metals (Ni, Cu, Cd) and nutrients levels registered in Barrosa water were associated with the observed oxidative stress responses by PCA. Despite the difficulty to establish cause-effect relationships due to the co-occurrence of various stressors and their interactions, the adopted integrated monitoring strategy appears to be promising.

Biomarker responses in mussels, an integrated approach to biological effects measurements

Biological effects techniques have been used with the aim to further integrate biological effects measurements with chemical analysis and apply these methods to provide an assessment of mussel health status. Live native mussels were collected from selected coastal and estuarine sites around the British Isles, including the rivers Test, Thames, Tees, and Clyde, and Lunderston Bay. A suite of biological effects techniques was undertaken on these mussels, including whole organism responses (scope for growth), tissue responses (histopathology), and subcellular responses (lysosomal stability, multi-xenobiotic resistance [MXR], and Comet assay). In addition, whole mussel homogenates were used to measure organic (polycyclic aromatic hydrocarbons [PAH], polychlorinated biphenyls [PCB]) and metal concentrations. Overall the mussels collected from the Thames were in relatively poor health, based on histopathological markers, significantly higher DNA damage, and elevated expression of MXR detoxifying proteins. In contrast, the mussels collected from the River Test were in the best health, based on histopathological markers, respiration rate (SFG), and low frequency of DNA damage. In conclusion, the biological effects techniques were able to distinguish between relatively contaminated and clean environments, with the Thames mussels in worst health. Mussel tissue chemistry data were not able to explain the variations in biological response. Evidence indicates that the difference in the health of the mussels between the different sites was due to either effects of contaminants that were not measured, or the combined effects of mixture toxicity resulting in a threshold effect.

Accumulation and histopathological damage in the clam Ruditapes philippinarum and the crab Carcinus maenas to assess sediment toxicity in Spanish ports

The degree of contamination and toxicity in sediment from four Spanish ports (Cádiz, Huelva, Pasajes and Bilbao) was assessed in the present study. Two marine invertebrate species, the shore crab Carcinus maenas and the clam Ruditapes philippinarum, were exposed to the different sediments under laboratory conditions for 28 days. Relationships were developed among metal contamination (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in sediments, metal accumulation in gill tissues and histopathological lesions in different biological tissues to assess sediment toxicity. A multivariate analysis approach was used to calculate sediment quality guidelines (SQGs) by linking metal concentration in sediments with histopathological lesions measured in the exposed organisms. The results showed significant contaminant accumulation and histopathological lesions due to As, Pb and Zn in sediments at the port of Huelva; As, Cr, Cu, Hg and Ni at the ports of Pasajes and Cádiz; and Cr and Hg at the port of Bilbao. The link between chemical concentration in sediments and histopathological lesions allowed the determination of SQGs for the chemicals As, Cd, Cu, Cr, Hg, Ni and Zn.

Histopathology of Antarctic krill, Euphausia superba, bearing black spots

Small black spots have been noticed on the cephalothorax of Antarctic krill, Euphausia superba, since January, 2001. To study the nature of the black spots, the krill were sampled in the winter of 2003, 2006, and 2007 in the South Georgia region, the Antarctic Ocean. Histological observations revealed that the black spots were melanized nodules that were composed of hemocytes surrounding either bacteria or amorphous material. In the 2007 samples, 42% of the krill had melanized nodules. Most of the nodules had an opening on the body surface of the krill. A single melanized nodule often contained more than one type of morphologically distinct bacterial cell. Three bacteria were isolated from these black spots, and classified into either Psychrobacter or Pseudoalteromonas based on the sequences of 16S rRNA genes. More than three bacterial species or strains were also confirmed by in situ hybridization for 16S rRNA. The melanized nodules were almost always accompanied by a mass of atypical, large heteromorphic cells, which were not observed in apparently healthy krill. Unidentified parasites were observed in some of the krill that had melanized nodules. These parasites were directly surrounded by the large heteromorphic cells. Histological observations suggested that these heteromorphic cells were attacking the parasites. These results suggest the possibility that the krill had been initially affected by parasite infections, and the parasitized spots were secondary infected by environmental bacteria after the parasites had escaped from the host body.

Pathology of Hematodinium infections in snow crabs (Chionoecetes opilio) from Newfoundland, Canada

Bitter crab disease (BCD) of snow crabs, Chionoecetes opilio, is caused by a parasitic dinoflagellate, Hematodinium sp. The disease has shown an alarming increase in prevalence in the commercial fishery in eastern and northeastern areas of Newfoundland and Labrador since it was first recorded there in the early 1990s. We documented histopathological alterations to the tissues in snow crabs with heavy infections of Hematodinium sp. and during sporulation of the parasite. Pressure necrosis was evident in the spongy connective tissues of the hepatopancreas and the blood vessels in most organs. In heavy infections, little remained of the spongy connective tissues around the hepatopancreas. Damage to the gills varied; in some cases it was severe, particularly during sporulation, involving apparent thinning of the cuticle, loss of epithelial cells, and fusion of the membranous layers of adjacent gill lamellae. Affected lamellae exhibited varying degrees of distention with a loss of trabecular cells, hemocyte infiltrations, and swelling or "clubbing" along the distal margins. Large numbers of zoospores were located along the distal margins of affected lamellae suggesting that sporulation may cause a lysis or bursting of the thin lamellar cuticle, releasing spores. Pressure necrosis, due to the build up of high densities of parasites, was the primary histopathological alteration in most tissues. Hematodinium infections in the snow crab are chronic, long-term infections that end in host death, during sporulation of the parasite.

An ecotoxicoproteomic approach (SELDI-TOF mass spectrometry) to biomarker discovery in crab exposed to pollutants under laboratory conditions

Ciphergen ProteinChip Technology is a proteomic tool, used for the discovery of new and sensitive biomarkers. This approach was used to evaluate the protein profile of crabs exposed to various pollutants. Two different exposure experiments were performed: spider crabs (Hyas araneus) were exposed for 3 weeks to diallyl phatalate (DAP), bisphenol A (BisA) and polybrominated diphenyl ether (PBDE-47), while shore crabs (Carcinus maeanas) were exposed to crude oil, crude oil spiked with alkylphenols (APs) and 4-nonylphenol (NP). Gender and species-related protein pattern alterations were observed and compared to controls. Results showed different responses to pollutants by the two species. Major disruption in protein peak expression was observed in samples exposed to mixtures of pollutants, i.e. oil spiked with APs. Compared to shore crab, spider crab species showed a lower degree of response in terms of number of altered protein peaks following exposure. In general, female individuals of both species showed a larger number of significantly altered proteins compared to males. Data analysis by non-metric multi-dimensional scaling (MDS) was performed. Bi-dimesional-MDS plots revealed a good separation of groups for both spider and shore crabs. In some cases, a good discrimination can also be observed between the two genders within each treatment. Results highlight the potential of crabs as sentinel organisms for the aquatic environment. The results indicate that SELDI-ToF technology is a powerful tool to discover protein expression signatures for different pollutants and sex dependent responses.