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At least 343 records · Page 19Linked to original sources
PubMed2004

Genomic dynamics of a low-copy-number satellite DNA family in Leptestheria dahalacensis (Crustacea, Branchiopoda, Conchostraca).

The LEP150 satellite DNA (satDNA) family found in Leptestheria dahalacensis (Ruppel, 1837) (Conchostraca) is a low-copy-number satellite with a canonical monomer of 150 bp. Nucleotide variation analyses suggest a 14-bp palindromic region as a possible protein binding site with constraints acting on the whole sequence but a 25-bp variable box. Besides the head-to-tail arrangement of 150 bp monomers, multimers analyses evidenced incomplete monomers, one duplication event, and three inversions. Both observed rearrangements and the higher values of sequence variability scored suggest that rearranged monomers reside in regions with a lower degree of homogenisation efficiency. Sixty-seven percent of the breakpoints occurs at kinkable dinucleotides, thus supporting their role in rearrangements as documented in alphoid satDNA recombination events. Monomers of different lengths may result from crossing over between repeats misaligned through the direct and inverted subrepeats of LEP150 monomers. ANOVA results indicate that the same range of sequence diversity is experienced at the individual and population ranks; therefore, the evolution of the L. dahalacensis satDNA is concerted.

Animals↗
PubMed2005

Acute toxicity of tributyltin to the Caprellidea (Crustacea: Amphipoda).

In order to compare the acute toxicity of tributyltin (TBT) between sexes, five species of caprellid amphipods were exposed to seven levels (0, 0.001, 0.01, 0.1, 1, 10 and 100 microg l(-1)) of TBT for 48 h at 20 degrees C. The 48-h LC50 values in male and female were 1.3-6.4 microg TBTCl l(-1) and 1.2-8.6 microg TBTCl l(-1), respectively. No sex-specific differences of the acute toxicity of TBT were observed in the caprellids. These findings suggest that the risk of survival in response to exposure to TBT between sexes is similar in the caprellids.

Animals↗
PubMed2006

Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatching and survival.

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell. Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.

Animals↗
PubMed2006

Fine structure of the secretory and sensory organs on the cephalon and the first pereionite of Trichoniscus alexandrae Caruso (Crustacea, Isopoda).

Trichoniscus alexandrae Caruso is a blind troglobiont isopod; males possess secretory and sensory organs on the cephalon and 1st pereionite consisting of cuticular pits hosting a tuft of setae and gland openings. Such organs are absent in females. Three types of cuticular structures have been observed: (a) lamellar setae, which likely play a role in protecting the gland openings and favouring the evaporation of secretions; (b) contact chemoreceptors, each provided with six bipolar sensory cells, a scolopale cell and enveloping cells; (c) a secretory cell complex, consisting of a long cylindrical slender duct-forming cell, with the function of transporting to the cuticular surface a secretion produced by two deeper secretory cells. The duct-forming cell is characterized by the presence of numerous microtubules in its cytoplasm, and is provided with a flattened duct. It is suggested that the secretion produced by the secretory cells could serve for sex-recognition.

Animals↗
PubMed2004

Sexual differentiation traits in functional males with female genital apertures (male symbol fga) in the woodlice Armadillidium vulgare Latr. (Isopoda, Crustacea).

This study reports the results of examination of the gonadal morphology and ultrastructural features of the androgenic hormone (AH)-producing androgenic gland cells of laboratory stocks of functional male woodlice, Armadillidium vulgare, with female genital apertures ( male symbol fga), with and without experimentally induced infections of the sex-ratio-distorting endobacterial parasite, Wolbachia. Males ( male symbol fga) have been reported in wild populations containing individuals infected with this maternally transmitted sex-ratio-distorting parasite. We report a reduction of testicular segment (utricle) number, androgenic gland cell hypertrophy, and electron-dense ultrastructural cytological features in male symbol fga males. The presence of the Wolbachia parasite had no effect on the features we examined. These results suggest that male symbol fga males are produced as the result of a delayed expression/action of the male sex-determining AH which causes a "lag-phase" delay in male differentiation in genetic males and is not due to the presence, in genetic females, of a hypothetical, epigenetic "M" gene as suggested by Rigaud and Juchault. Our results favor the interpretation of males as true genetic (ZZ) males in which the delayed AH action appears to involve cellular AH trafficking pathways which may be controlled by an impaired autosomal gene responsible for AH action.

Animals↗
PubMed2004

Molecular insights into Cumacean family relationships (Crustacea, Cumacea).

Cumaceans are a diverse order of small, benthic marine crustaceans. Phylogenetic hypotheses for the eight currently recognized cumacean families have not been formally proposed. However, based on external morphological traits and Linnean classification, a few conflicting hypotheses of relatedness have been proposed. Family definitions rely on morphological characters that often overlap and diagnoses are based on a combination of non-unique characters. Morphological analysis does not provide a well-resolved phylogeny. In the present study, we use amino acid sequences from the mitochondrial cytochrome oxidase I gene to produce a molecular phylogenetic hypothesis for the families of Cumacea. Phylogenetic analyses at the amino acid level were performed under Bayesian, likelihood, and parsimony methods. Results strongly suggest that families lacking an articulated telson form a monophyletic group. This pleotelson clade, composed of the families Bodotriidae, Leuconidae, and Nannastacidae, is the most derived within the Cumacea. Within this group, the Bodotriidae resolve paraphyletically, with Leuconidae and Nannastacidae embedded within it. Comparison of the molecular phylogeny with that based on morphology suggests that many "diagnostic" characters are homoplasious.

Animals↗
PubMed2003

Parasite transmission and cannibalism in an amphipod (Crustacea).

In its freshwater amphipod host Gammarus duebeni celticus, the microsporidian parasite Pleistophora mulleri showed 23% transmission efficiency when uninfected individuals were fed infected tissue, but 0% transmission by water-borne and coprophagous routes. Cannibalism between unparasitised and parasitised individuals was significantly in favour of the former (37% compared to 0%). In addition, cannibalism between parasitised individuals was significantly higher than between unparasitised individuals (27% compared to 0%). Thus, parasitised individuals were more likely to be cannibalised by both unparasitised and parasitised individuals. We discuss the conflicting selective forces within this host/parasite relationship, the implications of parasite mediated cannibalism for host population structure and the impacts this may have on the wider aquatic community.

Animals↗
PubMed2002

Effects of two acanthocephalan parasites on the fecundity and pairing status of female Gammarus pulex (Crustacea: Amphipoda).

Acanthocephalan parasites are known to alter the reproductive biology and physiology of their hosts in various ways. In this study we investigated the influence of two acanthocephalan parasites, Pomphorhynchus laevis and Polymorphus minutus, on the fecundity and pairing success of female Gammarus pulex. The results show that P. laevis and P. minutus affect female intermediate host reproduction in different ways. Females infected with P. minutus were totally castrated, whereas those infected with P. laevis only showed reduced fecundity. The oocytes of P. laevis-infected females showed a similar structure to those of uninfected females, although infected females had a higher proportion of oocytes that had failed to reach complete maturity. In comparison, the oocytes of P. minutus-infected females demonstrate a clearly altered structure that suggests a major disruption to the process of vitellogenesis. In the field, males paired more frequently with uninfected females than with infected ones, and is a stronger effect for P. minutus-infected females than P. laevis-infected females. We suggest that the difference in pairing success of P. minutus-infected and P. laevis-infected females is a direct result of the different effects that the two parasites have on female fecundity.

Acanthocephala↗
PubMed2002

Differences in the acute toxicities of tributyltin between the Caprellidea and the Gammaridea (Crustacea: Amphipoda).

Tests for the acute toxicity of tributyltin (TBT) were conducted on amphipod crustaceans collected from Otsuchi Bay, Japan. Five species of caprellids and three species of gammarids, which belong to a closely related ecological niche, were used for the exposure experiments at seven test concentrations (0, 0.001, 0.01, 0.1, 1, 10 and 100 microg TBTCl/l) for 48 h at 20 degrees C. The 48-h LC50 values of the caprellids were 1.2-6.6 microg TBTCl/l, and these were significantly lower than those of the gammarids (17.8-23.1 microg TBTCl/l). This suggests that caprellids are more sensitive to TBT than gammarids. Furthermore, the proportions of TBT and its derivatives, dibutyltin (DBT) and monobutyltin (MBT), were measured in the amphipods collected from Otsuchi Bay. In the caprellids, TBT was the predominant compound, accounting for 72% of the total butyltin which reflected the butyltin ratio in seawater, while in the gammarids, TBT's breakdown products (DBT and MBT) predominated, accounting for 75% of the total butyltin. This difference suggests that caprellids may have lower metabolic capacity to degrade TBT than gammarids. Therefore, the difference in sensitivity to TBT among the amphipods is thought to be related to the species-specific capacity to metabolize TBT.

Animals↗
PubMed2002

Short-term responses of Oryzias latipes (Pisces: Adrianichthyidae) and Macrobrachium nipponense (Crustacea: Palaemonidae) to municipal and pharmaceutical waste water in Beijing, China: survival, behaviour, biochemical biomarkers.

Whole effluent toxicity was assessed for the fish Oryzias latipes and the prawn Macrobrachium nipponense for 18 h in a dilution series (0-66%) of the inflow and effluent of a municipal waste water treatment plant as well as waste water from a teramycin producing pharmaceutical industry, before, during and after a pilot laboratory purification process. The waste waters caused acute toxicity as measured by inhibition of light emission in the luminiscent bacterium Vibrio qingaiensis sp. nov. (Q67). EROD and aryl hydrocarbon hydroxylase activity in in vitro carp liver-cells showed a dose-dependent toxic response to the municipal waste water. Behavioural responses and time-to-death of fish and prawn, recorded online with the "Multispecies Freshwater Biomonitor" proved to be concentration- and time-dependent sensitive toxicity indicators in both types of waste water. Behaviour changed stepwise from normal activity to (increased or decreased) activity to more time spent on ventilation and finally to increased morbidity at higher concentration and time of exposure. The municipal waste water treatment plant managed to reduce toxicity to bacteria (Q67), prawn and fish. The pharmaceutical waste water treatment process still has to be improved, in order to reduce toxicity for fish and prawn.

Animals↗
PubMed2006

Crustacea in Arctic and Antarctic sea ice: distribution, diet and life history strategies.

This review concerns crustaceans that associate with sea ice. Particular emphasis is placed on comparing and contrasting the Arctic and Antarctic sea ice habitats, and the subsequent influence of these environments on the life history strategies of the crustacean fauna. Sea ice is the dominant feature of both polar marine ecosystems, playing a central role in physical processes and providing an essential habitat for organisms ranging in size from viruses to whales. Similarities between the Arctic and Antarctic marine ecosystems include variable cover of sea ice over an annual cycle, a light regimen that can extend from months of total darkness to months of continuous light and a pronounced seasonality in primary production. Although there are many similarities, there are also major differences between the two regions: The Antarctic experiences greater seasonal change in its sea ice extent, much of the ice is over very deep water and more than 80% breaks out each year. In contrast, Arctic sea ice often covers comparatively shallow water, doubles in its extent on an annual cycle and the ice may persist for several decades. Crustaceans, particularly copepods and amphipods, are abundant in the sea ice zone at both poles, either living within the brine channel system of the ice-crystal matrix or inhabiting the ice-water interface. Many species associate with ice for only a part of their life cycle, while others appear entirely dependent upon it for reproduction and development. Although similarities exist between the two faunas, many differences are emerging. Most notable are the much higher abundance and biomass of Antarctic copepods, the dominance of the Antarctic sea ice copepod fauna by calanoids, the high euphausiid biomass in Southern Ocean waters and the lack of any species that appear fully dependent on the ice. In the Arctic, the ice-associated fauna is dominated by amphipods. Calanoid copepods are not tightly associated with the ice, while harpacticoids and cyclopoids are abundant. Euphausiids are nearly absent from the high Arctic. Life history strategies are variable, although reproductive cycles and life spans are generally longer than those for temperate congeners. Species at both poles tend to be opportunistic feeders and periods of diapause or other reductions in metabolic expenditure are not uncommon.

Animals↗
PubMed1996

IgE reactivity against a cross-reactive allergen in crustacea and mollusca: evidence for tropomyosin as the common allergen.

BACKGROUND: Although cross-reactivity between mollusks and other crustaceans in shrimp-sensitive subjects has been reported, the mechanism of this allergenic cross-reactivity has not been studied in detail. OBJECTIVE: To investigate this cross-reactivity in vitro, we have taken advantage of a complementary DNA that expresses tropomyosin, the immunodominant shrimp allergen. METHODS: Serum IgE from nine patients with known anaphylaxis to shrimp and five normal volunteers were analyzed by immunoblotting against 13 distinct crustaceans and mollusks. As additional antigens, muscle preparations were isolated from grasshopper, cockroach, fruit fly, chicken, and mouse. RESULTS: Sera from all patients, but not control subjects, reacted specifically with a 38 kd protein in all crustaceans and mollusks studied. In addition, 8 of 9 sera from patients, but from none of the normal control subjects, recognized proteins of various other molecular weights among the mollusk extracts studied. The 38 kd protein was identified as tropomyosin and was shown to share immunodominant epitopes among all species of crustaceans and mollusks tested by specific absorption studies. Moreover, sera from all nine subjects with shrimp allergy demonstrated IgE reactivities against grasshopper, cockroach, and fruit fly but not chicken or murine muscle. CONCLUSION: The allergic epitopes on tropomyosin are conserved among invertebrates including not only shellfish but also insects. This latter observation suggests that persons sensitive to shrimp should undergo further study for potential cross-reactive inhalant or ingested insect sensitivity.

Allergens↗
PubMed2002

Heavy metal concentrations in Squilla mantis (L.) (Crustacea, Stomatopoda) from the gulf of cadiz evaluation of the impact of the Aznalcollar mining spill.

After the Aznalcóllar mining spill (25th April 1998), considerable social concern arose amongst the inhabitants of the SW Iberian Peninsula concerning the consumption of local seafood. Squilla mantis was collected in four regions of the Gulf of Cádiz with a dual objective: to analyze the heavy metal levels for human consumption and as part of biomonitoring program. Heavy metal concentrations (Fe, Mn, Zn, Cu, Cd and Pb) were analyzed in soft tissues and cuticle. The highest values were found in the soft tissues for zinc, copper and cadmium and in the cuticle for iron, manganese and lead. The mean copper concentration in the soft tissue, corresponding to the edible part, was 27.1 microg x g(-1) wet weight. Approximately 80% of stations showed values higher than 20 microg x g(-1) wet weight of copper, the Spanish legal limit for the concentration of this metal in the crustacean for human consumption. For Zn and Cu no significant differences were found between regions, probably related with the capacity for regulation of S. mantis. The highest values found for copper in the Gulf of Cádiz compared to other areas is likely to be related with contamination from terrestrial mining activities (copper and pyrites) in the region, dating back to the times of Tartessians and Romans, rather than the effects of mining spill which was shown not to create any significant increases in heavy metal concentrations of organisms of the Guadalquivir River or the adjacent coastal area.

Animals↗