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PubMed2003

Use of a mathematical model in the analysis of survival curves of Daphnia magna exposed to toxicants.

Chronic toxicity tests carried out on species of the genus Daphnia (Crustacea: Cladocera) are bioassays commonly used in ecotoxicology. Mortality in the cohorts exposed to toxicants can be examined by the analysis of survival curves. The shape of these curves may be very different because of inter-individual heterogeneity: the less rectangular is the shape the more different is the probability of dying of daphnids in the cohort. Aim of this paper is to analyze the characteristics-in particular the shape-of survival curves of cohorts of Daphnia magna exposed to heavy metals in chronic toxicity tests. Experimental curves were fitted by a mathematical model recently proposed, which puts emphasis just on this heterogeneity, described by the parameter of the model S(0). The information contained in S(0) is very useful for the present purposes: the higher the value of S(0) the less rectangular the shape of the curve and, as a consequence, the higher the age-at-death heterogeneity of the cohort is thought to be. The model contains a second parameter, omega, representing the maximum potential ability of the individuals to survive in a specific environment and is related with the maximal life span. The model fitted well the survival curves in most cases and both S(0) and omega showed statistically different values between treatments, useful for comparisons. It was concluded that S(0) provides a quantitative estimation of curve "rectangularization", useful to check different sensitivities to a specific toxicant concentration among daphnids belonging to the same cohort, while omega provides an estimate of maximal life span.

Animals↗
PubMed2003

Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances.

A nitro musk (musk ketone) and three polycyclic musks (Tonalide, Galaxolide and Celestolide) were tested for acute and subchronic effects on a marine crustacean, the calanoid copepod Acartia tonsa. Sublethal effects on A. tonsa larvae were investigated with a rapid and cost effective bioassay, which is based on the easily detectable morphological change from the last nauplius to the first copepodite stage during copepod larval development. The inhibition of larval development after 5 days exposure was a very sensitive endpoint, with 5-d-EC(50)-values as low as 0.026 mg/l (Tonalide), 0.059 mg/l (Galaxolide), 0.066 mg/l (musk ketone) and 0.160 mg/l (Celestolide), respectively. These values were generally more than one order of magnitude below the 48-h-LC(50)-values found for adults, which were 0.47 mg/l (Galaxolide), 0.71 mg/l (Celestolide), 1.32 mg/l (musk ketone) and 2.5 mg/l (Tonalide). Since the synthetic musks strongly inhibited larval development in A. tonsa at low nominal concentrations, they should be considered as very toxic. The larval development test with A. tonsa is able to provide important aquatic toxicity data for the evaluation of synthetic musks, for which there is little published ecotoxicological information available regarding Crustacea. It is suggested that subchronic and chronic copepod toxicity tests should be used more frequently for risk assessment of environmental pollutants.

Animals↗
PubMed2003

Long-term studies (1871-2000) on acidification and recovery of lakes in the Bohemian Forest (central Europe).

This paper evaluates long-term changes in the atmospheric depositions of S and N compounds, lake water quality, and biodiversity at eight glacial lakes in the Bohemian Forest over the past 130 years. This time interval covers (i) the 'background' pre-acidification status of the lakes, (ii) a period of changes in the communities that can be partly explained by introduction of fish, (iii) a period of strong lake acidification with its adverse impacts on the communities, (iv) the lake reversal from acidity, which includes the recent status of the lakes. The lake water chemistry has followed-with a characteristic hysteresis-both the sharp increase and decline in the deposition trends of strong anions. Remarkable changes in biota have mirrored the changing water quality. Fish became extinct and most species of zooplankton (Crustacea) and benthos (Ephemeroptera and Plecoptera) retreated due to the lake water acidification. Independent of ongoing chemical reversal, microorganisms remain dominant in the recent plankton biomass as well as in controlling the pelagic food webs. The first signs of the forthcoming biological recovery have already been evidenced in some lakes, such as the population of Ceriodaphnia quadrangula (Cladocera) returning into the pelagial of one lake or the increase in both phytoplankton biomass and rotifer numbers in another lake.

Acid Rain↗
PubMed2001

Effects of molting and environmental factors on trace metal body-burdens and hemocyanin concentrations in the American lobster, Homarus americanus.

Hemocyanin concentrations in the hemolymph of marine crustacea are dependent on the molt cycle and on environmental conditions. Studies in our laboratories have found that hemocyanin levels in blue crabs are reduced after ecdysis and under conditions of environmental stress (Engel, Brouwer, & McKenna, 1993. Hemocyanin concentrations in marine crustaceans as a function of environmental conditions. Marine Ecology Progress Series, 93, 233-244). We have extended those studies to include the American lobster, Homarus americanus. Hemolymph and digestive gland tissues from Long Island Sound lobsters were analyzed for hemocyanin, copper, and zinc during different stages of the molt cycle. Hemocyanin, copper and zinc in the hemolymph were highest in premolt stages (D1-D4), and lowest in the postecdysal papershell stages (B1-B2). Concomitantly, copper in digestive glands decreased significantly following ecdysis, but no significant changes in the metals bound to metallothionein (MT) were observed. Copper-MT was the predominant form throughout the molt cycle, presumably because lobsters were obtained from copper-contaminated areas. To examine the effects of environmental factors, intermolt lobsters were collected from locations of different environmental quality along the Atlantic coast, and were analyzed for hemocyanin and trace metals. In general, animals from areas with a history of contamination showed the highest hemocyanin concentrations.

Animals↗
PubMed2001

Flux of heavy metal accumulation in various organs of the intertidal marine blue crab, Portunus pelagicus (L.) from the Kuwait coast after the Gulf War.

The metal levels of arsenic, chromium, copper, lead, magnesium, manganese, selenium, vanadium, and zinc concentrations were determined in various body organs, viz., hepatopancreas, gills, gonad, gastric stomach, and muscle of the blue crab, Portunus pelagicus (Crustacea: Decapoda) to assess the bioaccumulation of metals associated with petroleum input a decade after the 1991 Gulf War oil spillage. Sample solutions prepared were analyzed using an atomic absorption spectrophotometry. High concentrations of Zn and Cu in the muscle and hepatopancreas tissues were a strong indicative of high exposure of P. pelagicus to these metals. However, muscle tissue had been found to accumulate the highest values for all metal speciations analyzed. Copper, zinc, and chromium in samples collected from Station II covering the Kuwait City area were often in excess of those present in Station I and III. Arsenic, lead, magnesium, manganese, selenium, and vanadium were greater in individuals obtained from Station I. A significant correlation was found to exist between Se and V in crab muscle with a surge in Se metal concentration, which was found to be inversely proportional to that of V metal concentration irrespective of the sex of the crab. The difference in patterns of metal occurrence and the significant increase in the Cu and Zn concentrations in various organs of the crab were largely associated with the 1991 Gulf War oil spill. Such results could be used as a baseline for the monitoring of the level of metals in marine organisms of future studies.

Animals↗
PubMed2000

Impact of the fungicide carbendazim in freshwater microcosms. I. Water quality, breakdown of particulate organic matter and responses of macroinvertebrates.

Effects of chronic application of the fungicide Derosal(R) (active ingredient carbendazim) were studied in indoor macrophyte-dominated freshwater microcosms. The concentrations (0, 3.3, 33, 100, 330 and 1000 µg/l) were kept at a constant level for 4 weeks. This paper is the first of a series of two, and describes the fate of carbendazim and its effects on water quality parameters, breakdown of POM, and responses of macroinvertebrates. Carbendazim proved very persistent in the water layer. Values for t(12) varied between 6 and 25 weeks, and decreased with the treatment level. Significant effects on water quality parameters (DO, pH, alkalinity, conductivity) could not be demonstrated. After 4 weeks of incubation, the breakdown of Populus leaves was significantly slower at the two highest carbendazim concentrations. The macroinvertebrate community was seriously affected by carbendazim application, with Oligochaeta, Turbellaria, Hirudinea and some Crustacea as the most sensitive groups. The snail Bithynia decreased in numbers, but other gastropods increased in numbers. Safety factors as proposed by the Uniform Principles (European Union) for the risk assessment of pesticides, to be multiplied with toxicity data of the standard test species (Daphnia, fish, algae), appeared to ensure adequate protection of sensitive populations present in the microcosms.

Journal Article↗
PubMed2003

Assessment of fluorescent-labeled bacteria for evaluation of in vivo uptake of bacteria (Vibrio spp.) by crustacean larvae.

Available methods to study crustacean digestive tract colonization by bacteria are laborious, time-consuming, and do not permit in vivo assays and observation. This paper reports on a rapid and consistent technique to apply a fluorescent label to bacteria, which can then be presented to filter-feeding crustacea such as Artemia and penaeid larvae for later in situ bacterial distribution observation. Three luminescent Vibrio spp. were stained and observed inside Artemia nauplii, shrimp zoea and mysis stages, Vibrio harveyi type strain ATCC 14126, M(1) (pathogenic) and Ea (non-pathogenic). Factors such as dye (DTAF) concentration, exposure time/temperature and sonication time were evaluated. Viability of the dye and stained bacteria were tested at 4, -20 and -70 degrees C storage temperatures for up to 81 days. Results show that 4 and -20 degrees C storage temperatures are not recommended. At -70 degrees C, both bacteria and dye are optimally preserved. Monodispersed fluorescent-labeled bacterial cells can be observed inside the digestive tract of crustacean larvae at a density of inoculation as high as 5.2 x 10(6) CFU ml(-1). After 2 to 4 h, some leaching occurs, increasing difficulty in observation, although after 24 h, it is still possible to observe monodispersed FLB inside the digestive tract of crustacean larvae. Autofluorescence may complicate observation when filter-feeding crustacean larvae are co-fed with microalgae.

Animals↗
PubMed2003

Nasal delivery of chitosan-DNA plasmid expressing epitopes of respiratory syncytial virus (RSV) induces protective CTL responses in BALB/c mice.

Respiratory syncytial virus (RSV), an important pathogen of the lower respiratory tract, is responsible for severe illness both in new born and young children and in elderly people. Due to complications associated with the use of the early developed vaccines, there is still a need for an effective vaccine against RSV. Most pathogens enter the body via mucosal surfaces and therefore vaccine delivery via routes such as the nasal, may well prove to be superior in inducing protective immune responses against respiratory viruses, since both local and systemic immunity can be induced by nasal immunisation. Previously we have shown that intradermal immunisation of a plasmid DNA encoding the CTL epitope from the M2 protein of RSV induced protective CTL responses. In the present study, the mucosal delivery of plasmid DNA formulated with chitosan has been investigated. Chitosan is a polysachharide consisting of copolymers of N-acetylglucosamine and glucosamine that is derived from chitin, a material found in the shells of crustacea. Intranasal immunisation with plasmid DNA formulated with chitosan induced peptide- and virus-specific CTL responses in BALB/c mice that were comparable to those induced via intradermal immunisation. Following RSV challenge of chitosan/DNA immunised mice, a significant reduction (P<0.001) in the virus load was observed in the lungs of immunised mice compared to that in the control group. These results indicate the potential of immunisation with chitosan-formulated epitope-based vaccines via the intranasal route.

Animals↗
PubMed2001

Variability in the edible fraction content of 60Co, 99Tc, 110mAg, 137Cs and 241Am between individual crabs and lobsters from Sellafield (north eastern Irish Sea).

We investigated the variability of anthropogenic radionuclide content of the edible fractions of individual edible crabs (Cancer pagurus L.) and European lobsters (Homarus gammarus L.) caught commercially in the Sellafield offshore area. Sixteen female and 18 male crabs and 20 female and 17 male lobsters were selected from commercial catches made between 25 May and 5 June 1997. Each gender group was selected to be within the known weight range for commercially caught crustacea from the area. Four artificial radionuclides (60Co, 110mAg, 137Cs or 241Am) were detected by gamma-spectrometry. The edible fraction content of these radionuclides between males and females for either species were not statistically significantly different. 99Tc was analysed by chemical separation and beta-counting. 99Tc concentrations in female crabs tended to be higher (172 +/- 205 (16) Bq kg-1(wet); mean +/- standard deviation (n samples)) than those in males (85 +/- 58 (18) Bq kg-1 (wet)), although this was not a statistically significant difference. For both male and female crabs, 99Tc concentrations tended to decrease with increasing whole live weights. For 99Tc in lobsters the picture is less clear. Female lobsters contained more activity (14800 +/- 7400 (20) Bq kg-1 (wet)) than males (7100 +/- 3900 (17) Bq kg-1 (wet)). The results were used to discuss the implications for sampling and monitoring.

Animals↗
PubMed1997

The effects of conservation tillage practices on benthic invertebrate communities in headwater streams in southwestern Ontario, Canada.

Samples of benthic invertebrates from four pairs of streams in southwestern Ontario collected monthly from May through August 1991, and once during the subsequent autumn and winter, demonstrated that conservation tillage practices have a remedial effect on the water quality of adjacent streams as indicated by biotic, rather than physical or chemical, parameters. One stream of each pair drained a basin under conventional tillage (CONV, mainly mouldboard ploughing), the other primarily under conservation tillage (CONS). The paired drainage basins were otherwise similar to one another in type of crops grown, as well as size, topography, soils and hydrology. CONS streams yielded a greater variety of Insecta but fewer taxa of Mollusca, Annelida and Crustacea than did samples from CONV streams. Both kick-net and Surber samples from CONS streams yielded significantly more taxa, more kinds of Ephemeroptera, Plecoptera and Trichoptera, and lower Hilsenhoff Biotic Index scores than did samples from CONV streams. Kick samples from CONS streams were significantly more similar to expected reference communities in overall taxonomic composition. Surber samples from CONS streams contained significantly larger numbers of invertebrates. The relatively greater abundances of infaunal species, especially Tubificidae and Chironomini, in CONV streams suggest greater accumulation of fine sediment particles. Conditions during low flow appear to have the greatest influence on the composition of benthic invertebrate communities. The results of the study indicate that conservation tillage practices have a beneficial effect on the quality of surface waters.

Journal Article↗
PubMed1999

Temporal and spatial biomonitoring of heavy metals in Hong Kong coastal waters using Tetraclita squamosa.

The barnacle Tetraclita squamosa (Crustacea: Cirripedia) was collected from 11 sites in the coastal waters of Hong Kong during three consecutive seasons, i.e. summer 1996, winter 1996-1997 and summer 1997. Barnacle soft tissues were analysed for cadmium, copper, manganese, iron and zinc using inductively coupled plasma atomic emission spectrophotometry. Analysis of covariance allowed inter-seasonal (temporal) and inter-site (spatial) comparisons of soft tissue metal concentrations to be made, from which bioavailabilities to T. squamosa have been inferred. Inter-seasonal variation was not greater than intra-seasonal and, therefore, seasonal variation in soft tissue metal concentrations can be considered relatively unimportant. Data were, however, characterised by high temporal variability. Spatial variation in metal bioavailabilities were consistent with earlier studies: cadmium soft tissue concentrations were elevated in barnacles collected from low salinity western waters, while copper and zinc concentrations were elevated in the urban-fringed central waters, in particular at one site, i.e. Aberdeen. In general, metal concentrations were much lower in barnacles collected from eastern water sites.

Journal Article↗
PubMedDate not supplied

Anaphylactic shock to oysters and white fish with generalized urticaria to prawns and white fish.

Because seafood consumption is moderate-to-high in Spain, allergic reactions to seafood such as fish, crustacea and mollusc are fairly frequent. The clinical features of these reactions depend on the implicated species and whether the reaction is provoked by ingestion, handling or vapor inhalation. Because different species have common antigenic structures, cross-sensitization is frequent, especially between crustaceans and molluscs. Contamination of fish by nematodes (Anisakis) may produce severe reactions. We report the case of a female patient with no personal or family history of allergy who experienced two episodes of anaphylactic shock: the first occurred immediately after eating oysters and the second after ingestion of white fish. The patient also developed generalized urticaria provoked by crustacean (prawns) and white fish. The results of skin prick tests were negative for fish, shellfish, crustacean and oysters while in vitro tests were positive for oyster, prawns, Anisakis, Ascaris and Echinococcus, although stool samples and gastric endoscopy were negative.

Allergens↗
PubMed2001

Two types of urate binding sites on hemocyanin from the crayfish Astacus leptodactylus: an ITC study.

The oxygen binding behaviour of hemocyanins from Crustacea is regulated by small organic compounds such as urate and L-lactate. We investigated the binding characteristics of urate and the related compound caffeine to the 2 x 6-meric hemocyanin of A. leptodactylus under fully oxygenated conditions employing isothermal titration calorimetry (ITC). An analysis of urate and caffeine binding based on a model of n identical binding sites resulted in approximately four binding sites for caffeine and eight for urate. This result suggests that the binding process for these effectors is more complex than this most simple model. Therefore, we introduced a number of alternative models. Displacement experiments helped to select the appropriate model. Based on these experiments, at least two different types of binding sites for urate and caffeine exist on the 2 x 6-meric hemocyanin of A. leptodactylus. The two binding sites differ strongly in their specificity towards the two analogues. It can be hypothesized that two different subunit types (beta and gamma) are responsible for the two types of binding sites.

Animals↗
PubMed2002

Characterization of crab EcR and RXR homologs and expression during limb regeneration and oocyte maturation.

We report here complete coding sequences for the Uca pugilator homologs of the ecdysteroid (UpEcR) and retinoid-X receptors (UpRXR). Library screenings recovered cDNA clones containing a unique amino terminal open-reading frame (A/B domain) for each gene, most similar to insect B1 EcR and USP1/RXR isoforms. Splicing variants in the UpRXR ligand-binding domain were also identified, in a region critical for folding of Drosophila and lepidopteran USP. UpEcR and UpRXR proteins were able to associate, and both are required for binding to an ecdysteroid HRE; these interactions were not hormone-dependent. Ribonuclease protection assays (RPA) were conducted using A/B domain and 'common' (C or E) domain probes on RNA isolated from various stages of regenerating limb buds and ovaries. For several of the limb bud and ovarian stages examined, the relative level of A/B domain sequence protected was significantly less than common domain suggesting alternative amino terminal isoforms other than those isolated through cloning. This is the first report of UpEcR and UpRXR transcription during ovarian maturation, implicating the ovary as a potential target for hormonal control in Crustacea.

Amino Acid Sequence↗
PubMed2000

Characterization of (Na+, K+)-ATPase in gill microsomes of the freshwater shrimp Macrobrachium olfersii.

To better understand the adaptive strategies that led to freshwater invasion by hyper-regulating Crustacea, we prepared a microsomal (Na+, K+)-ATPase by differential centrifugation of a gill homogenate from the freshwater shrimp Macrobrachium olfersii. Sucrose gradient centrifugation revealed a light fraction containing most of the (Na+, K+)-ATPase activity, contaminated with other ATPases, and a heavy fraction containing negligible (Na+, K+)-ATPase activity. Western blotting showed that M. olfersii gill contains a single alpha-subunit isoform of about 110 kDa. The (Na+, K+)-ATPase hydrolyzed ATP with Michaelis Menten kinetics with K5, = 165+/-5 microM and Vmax = 686.1+/-24.7 U mg(-1). Stimulation by potassium (K0.5 = 2.4+/-0.1 mM) and magnesium ions (K0.5 = 0.76+/-0.03 mM) also obeyed Michaelis-Menten kinetics, while that by sodium ions (K0.5 = 6.0+/-0.2 mM) exhibited site site interactions (n = 1.6). Ouabain (K0.5 = 61.6+/-2.8 microM) and vanadate (K0.5 = 3.2+/-0.1 microM) inhibited up to 70% of the total ATPase activity, while thapsigargin and ethacrynic acid did not affect activity. The remaining 30% activity was inhibited by oligomycin, sodium azide and bafilomycin A. These data suggest that the (Na+, K+)-ATPase corresponds to about 70% of the total ATPase activity; the remaining 30%, i.e. the ouabain-insensitive ATPase activity, apparently correspond to F0F1- and V-ATPases, but not Ca-stimulated and Na- or K-stimulated ATPases. The data confirm the recent invasion of the freshwater biotope by M. olfersii and suggest that (Na+, K+)-ATPase activity may be regulated by the Na+ concentration of the external medium.

Animals↗
PubMed1998

Genomic organisation and polymorphism of a crustacean trypsin multi-gene family.

The coding sequences of three trypsin genes, obtained by polymerase chain reaction (PCR), were determined in Penaeus vannamei (Crustacea, Decapoda). These genes were characterised by two short introns, which occur at a position quasi-conserved as the first two introns in vertebrate counterparts. Belonging to three different families, two of the genes are expressed in the digestive gland. A 5' RACE-PCR amplification of hepatopancreatic mRNA, together with the presence of short 5' extensions, confirmed that the third gene family is not expressed in this tissue. The second intron in the genes expressed in the hepatopancreas presents a 5' splice site consensus, beginning with a GC motive which is reported for the first time in trypsin genes and is of phase I in mammals. A high copy number was determined for these genes. Several restricted PCR were performed to describe the polymorphism of these sequences. Five genes were partially sequenced for each family and five genes coding the different, previously described cDNAs were recovered. These sequences also confirm that the third family resembles a mosaic of type I and type II gene families. A high degree of polymorphism in the introns (54-59% identity) among the three families is observed, but mutations in corresponding introns inside each of the families are low (3-6%).

Amino Acid Sequence↗
PubMed2002

Reproductive and developmental effects of endocrine disrupters in invertebrates: in vitro and in vivo approaches.

In order to gain basic understanding in the ecotoxicity of endocrine disrupting chemicals or EDCs (including natural chemicals and some pharmaceuticals), many international research groups are currently testing these chemicals using aquatic invertebrates. This paper discusses relevant examples to address key questions: which aquatic invertebrates are likely to be vulnerable to mammalian and non-mammalian EDCs; and which types of invertebrate chronic tests might be most sensitive and cost-effective to address potential environmental exposures? For a full review of invertebrate endocrine disrupter research see Endocrine Disruption in Invertebrates: Endocrinology, Testing and Assessment (1999). As an example, crustaceans are a particular focus of EDC research, reflecting their abundance in nature, commercial importance and their inclusion in the regulatory assessment schemes for active pharmaceutical ingredients (APIs). There is a diverse literature on the developmental and reproductive effects of mammalian EDCs in Crustacea, although there is growing evidence that such effects are probably not mediated via arthropod hormone systems. For example, recent studies in Europe using a marine copepod (Tisbe battagliai) life-cycle test have evaluated ecdysteroid agonists (e.g. 20-hydroxyecdysone), oestrogen agonists (e.g. diethylstilbestrol (DES), 17beta-oestradiol, oestrone and 17alpha-ethynylestradiol) and the pharmaceutical anti-oestrogen (ZM189, 154). While 20-hydroxyecdysone and DES were highly toxic, the other compounds tested show no significant toxicity to copepods. Furthermore, in vitro studies indicate that these environmental EDCs and several related APIs are not active against the ecdysteroid receptor. Therefore, other undefined modes of action appear to be responsible for crustacean toxicity in vivo and caution should be exercised before ascribing any apical effects to endogenous endocrine mechanisms, or before crustacean "EDC" data are extrapolated to other invertebrate taxa.

Animal Testing Alternatives↗
PubMed2001

[Notes on the biology of the deep-water shrimp Aristeus antillensis in French Guiana].

In order to describe some aspects of the biology of the deep-water shrimp Aristeus antillensis (Crustacea, Decapoda, Aristeidae) in French Guiana (Western Central Atlantic), a total of 84 bottom trawls were carried out at bottom depths ranging from 200 to 900 m on the Guianan slope during four scientific surveys conducted from August 1990 through July 1991. A. antillensis is distributed in muddy grounds from 456 to 818 m with a peak abundance in the 500-600-m-depth stratum where mean catch rates are about 400 g.h-1. In terms of biomass, catches obtained in day time and at night are similar. All samples observed show great predominance of females. The size frequency distribution indicates the existence of three age-classes for females, probably attributed to three annual cohorts. The results of a detailed study of morphometric relationships (length-weight relationships) are also presented.

Aging↗