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At least 793 records · Page 44Linked to original sources
PubMed2006

Distribution of choline acetyltransferase immunoreactivity in the alimentary tract of the barnacle Balanus amphitrite (Cirripedia, Crustacea).

To date only peptidergic innervation has been described in the alimentary tract of barnacles. In the present work the presence and distribution of choline acetyltransferase (ChAT), the acetylcholine (ACh) synthesizing enzyme, was investigated by immunohistochemistry in the alimentary tract of the adult barnacle Balanus amphitrite. Numerous ChAT-immunoreactive (IR) cells and a net of ChAT-IR cytoplasmic processes were localized inside the epithelium of the posterior midgut, close to the basement membrane; no IR nerve endings were detected in the midgut longitudinal and circular muscle bundles. Epithelial neurons or endocrine cells in the gut epithelium have been described in some invertebrate species belonging to different taxa and their peptidergic features are reported in the literature. Our results point out the presence of neuroepithelial cells also in the gut epithelium of barnacles; moreover, for the first time, a cholinergic feature is suggested for this cell type. These data seem to indicate the involvement of ACh in the gut functions of barnacle and suggest that the barnacle alimentary tract is more complex than previously thought and requires further study.

Acetylcholine↗
PubMed2004

Trace elements in the muscle of red shrimp Aristeus antennatus (Risso, 1816) (Crustacea, Decapoda) from Ligurian sea (NW Mediterranean): variations related to the reproductive cycle.

Concentrations of total and organic mercury, cadmium, lead, copper, iron, manganese and zinc were determined in the muscular tissue of 135 specimens of Aristeus antennatus (Risso, 1816) collected during a 3-year period in the Ligurian sea (NW Mediterranean). The aim of the present work was to study the relationships between the concentrations of these trace elements and the main biological parameters characterising the organisms, i.e. sex and size with special attention to the sexual maturity of the female specimens. Mercury is the only element showing a significant correlation with the size of the specimens, and for this reason it could give some indications about the age of the shrimps. However, comparison between females collected at four different reproductive phases shows that reproductive individuals are characterised by higher levels of mercury with respect to non-reproductive individuals of the same size.

Animals↗
PubMed2006

Feeding behaviour of the terrestrial isopod Porcellionides pruinosus Brandt, 1833 (Crustacea, Isopoda) in response to changes in food quality and contamination.

Soil decomposition is mainly dependent on the nature and characteristics of organic matter within the soil, the environmental conditions and the activity of microorganisms and soil fauna. Isopods play an important role in decomposition through litter fragmentation and stimulating and/or ingesting fungi and bacteria. The aim of this study was to jointly evaluate the effect of different food types and the effect of heavy metal contamination of those foods through isopod feeding performance assays. These studies used the terrestrial isopod Porcellionides pruinosus. After feeding with different leaf types for the study on feeding performance, alder leaves were chosen for the contamination experiments. Feeding parameters like consumption, assimilation, egestion and growth ratios were calculated and compared among treatments and food type. Lower quality food decreased isopods performance. Exotic food types were shown to be less preferred than alder or oak leaves. Contaminated food also resulted in a decrease in performance among the feeding parameters studies, although isopods can tolerate in certain cases high amounts of heavy metals. For this reason it is possible that in future this crustacean can be used as bioindicators of soil contamination or in the evaluation of contaminated sites or remediation processes.

Alnus↗
PubMed2004

The glycosylated androgenic hormone of the terrestrial isopod Porcellio scaber (Crustacea).

It appears from grafting experiments that the androgenic hormone (AH) of terrestrial isopods has a narrow species-specificity [J. Crust. Biol. 19 (1999) 684], even if AH of different species shared common epitopes [Gen. Comp. Endocrinol. 125 (2002) 218]. To date only the glycosylated AH of the woodlouse Armadillidium vulgare has been deciphered by us [Ann. New York Acad. Sci. 839 (1998) 111; Eur. J. Biochem. 262 (1999) 727] and [Biochem. Biophys. Res. Commun. 264 (1999) 419] have confirmed the primary structure of this protein. We reported in the present paper the characterization of the AH in another species Porcellio scaber by a combination of microsequencing, mass spectrometry, and molecular cloning. We found only one glycoform which consisted of two peptide chains, A and B, of 31 and 44 amino acids, respectively, with A chain carrying on Asn18 a N-glycosylated moiety, size of which has been determined by MALDI-MS measurements. The expected structure of the glycosylation was proposed. The deduced amino acid sequence of the AH precursor was mainly identical to the one obtained independently by another group [Zool. Sci. 20 (2003) 75]. We also showed that AH gene is exclusively expressed in androgenic glands. Sequence comparison with A. vulgare and P. scaber (population of Japan) AH was discussed.

Amino Acid Sequence↗
PubMed2005

Complete sequence of Litopenaeus vannamei (Crustacea: Decapoda) vitellogenin cDNA and its expression in endocrinologically induced sub-adult females.

The gene that encodes vitellogenin (Vg), the precursor of the major yolk protein, vitellin, is expressed during vitellogenesis in decapod crustaceans. In this study, we sequenced the full-length cDNA from the Pacific white shrimp Litopenaeus vannamei Vg gene (LvVg). This is the first open thelycum penaeid shrimp Vg cDNA to be sequenced. The transcript encodes a 2587 amino acid polypeptide with up to 85% identity to Vg of different penaeid species. Peptide mass fingerprints (PMFs) of the vitelline polypeptides suggest that the predicted endoprotease cleavage site at amino acids 725-728 does indeed undergo cleavage. Five prominent high-density lipoprotein polypeptides of masses 179, 113, 78, 61, and 42kDa were isolated from vitellogenic ovary, and their PMFs were determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) spectrometry. It is likely that these polypeptides are all products of the LvVg gene. Removal of the X-organ sinus gland complex (XO-SG), which secretes the neurohormones that control the endocrine system regulating molt and reproduction, can induce both these processes. During the course of a number of molt cycles in induced sub-adult females, periodic ovarian growth and resorption were observed. Ovary growth correlated with LvVg expression in both the hepatopancreas and the ovary. Expression in ovaries of induced intermolt-early premolt females was significantly higher compared to all other sub-groups. Expression in ovaries of induced females was significantly higher compared to hepatopancreas at all molt cycle stages. Periodicity of molt and vitellogenesis in endocrinologically induced sub-adult shrimps may serve as a model to study alternate regulation of gene expression during these two processes.

Amino Acid Sequence↗
PubMed2004

A preliminary molecular and morphological phylogeny of the Antarctic Epimeriidae and Iphimediidae (Crustacea, Amphipoda).

The phylogenetic relationships of 14 species of the Antarctic amphipod families Epimeriidae and Iphimediidae were investigated using 553bp of the gene for the mitochondrial cytochrome oxidase subunit I (COI) and 98 morphological characters. Both families are dominant members of the Antarctic benthic amphipod community. In contrast to previous studies, our molecular and morphological data suggest that the families Epimeriidae and Iphimediidae may not be sister taxa. Our study suggests that Iphimediidae are more closely related to Eusirus (Eusiridae) than to Epimeria (Epimeriidae). Phylogenetic analyses based on maximum parsimony (MP) and maximum likelihood (ML) indicate that the genera Iphimediella and Gnathiphimedia are not monophyletic.

Amphipoda↗
PubMed2004

Rapid radiation and cryptic speciation in squat lobsters of the genus Munida (Crustacea, Decapoda) and related genera in the South West Pacific: molecular and morphological evidence.

Squat lobsters (genus Munida and related genera) are among the most diverse taxa of western Pacific crustaceans, though several features of their biology and phylogenetic relationships are unknown. This paper reports an extensive phylogenetic analysis based on mitochondrial DNA sequences (cytochrome c oxidase subunit I and 16S rRNA) and the morphology of 72 species of 12 genera of western Pacific squat lobsters. Our phylogenetic reconstruction using molecular data supports the recent taxonomic splitting of the genus Munida into several genera. Excluding one species (M. callista), the monophyly of the genus Munida was supported by Bayesian analysis of the molecular data. Three moderately diverse genera (Onconida, Paramunida, and Raymunida) also appeared monophyletic, both according to morphological and molecular data, always with high support. However, other genera (Crosnierita and Agononida) seem to be para- or polyphyletic. Three new cryptic species were identified in the course of this study. It would appear that the evolution of this group was marked by rapid speciation and stasis, or certain constraints, in its morphological evolution.

Animals↗
PubMed2006

The Petrolisthes galathinus complex: species boundaries based on color pattern, morphology and molecules, and evolutionary interrelationships between this complex and other Porcellanidae (Crustacea: Decapoda: Anomura).

While the amphi-American porcellanid crab Petrolistes galathinus has been traditionally viewed as a highly variable species containing several different color forms, we consider it to be a complex of at least 6 morphologically similar species with similar ecological requirements, but diagnosable through coloration. Here we surveyed sequence variation of the mitochondrial 16S rRNA gene, compared the morphology of adults and of the first larval stage (Zoea I), and explored shape variation of the sternal plate using geometric morphometric methods, to investigate boundaries among the species in the complex, and to confirm the validity of color and color pattern for distinguishing them. Sequences and larval morphological characters of other porcellanids were included to investigate the correspondence between genetic divergence and morphology of adults and larvae. The molecular and morphometric results support the validity of the species in the complex, and of color pattern for their distinction. The close relationship between the complex and the putative ancenstral porcellanid Parapetrolisthes tortugensis was indicated by the molecular and larval-morphology results. The adult morphology of this species is interpreted as a result of convergent evolution driven by a relatively rapid ecological adaptation to conditions in deeper waters. The nesting position in the phylogenetic trees of Petrocheles australiensis outside the Porcellanidae clade questions the monophyly of this family.

Animals↗
PubMed1997

Molecular cloning of hemocyanin cDNA from Penaeus vannamei (Crustacea, Decapoda): structure, evolution and physiological aspects.

Hemocyanin is present as 2 subunits in the hemolymph of Penaeus vannamei. Isolated from a hepatopancreas cDNA library of this penaeid shrimp, the cDNA chain (2095 bp) corresponds to a full length hemocyanin messenger as determined by Northern hybridization, with a short 5' untranslated region (17 bp), an open reading frame (1989 bp counting initiation and termination codons) coding for a signal peptide (13 residues) and a mature hemocyanin (648 amino acids), and a 3' untranslated region (89 bp) followed by the polyadenylated track. It is the first time that the existence of a hydrophobic signal peptide is shown in arthropod hemocyanin. Two primary N-terminal sequences are determined and a 3-fold increase of mRNA content, measured in the hepatopancreas during the premoult stages, is reported. The low level of polymorphism shown by P. vannamei hemocyanin, along with its weak percentage identity with counterparts and its similarity with hemocyanin from Panulirus interruptus, suggests that this arthropod hemocyanin may be a primitive subunit that has evolved independently, following gene duplication.

Amino Acid Sequence↗
PubMed2003

Localization of crustacean hyperglycemic and vitellogenesis-inhibiting hormones in separate cell types in the protocerebrum of the woodlouse Armadillidium vulgare (Crustacea, Isopoda).

We gave an accurate immunolocalization of CHH (crustacean hyperglycemic hormone) and VIH (vitellogenesis-inhibiting hormone) in the brain and the sinus gland of the woodlouse Armadillidium vulgare. The two immune sera have been respectively raised against HPLC-purified CHH and against a small peptide derived from the N-terminus of VIH. By immunocytochemistry, we showed that CHH and VIH were synthesized in different perikarya and stored in different axon endings of the sinus gland. As in other crustacean species studied to date, CHH was located in the axon endings filled with the biggest granules. Immunoblotting confirmed that VIH was stored in the sinus glands of both the female and the male. These clear localizations of CHH- and VIH-antigens do not preclude that only one peptide is released from a given type of SG endings and do not rule out that each peptide can be involved in the control of different physiological processes.

Animals↗
PubMed2003

Parasite altered micro-distribution of Gammarus pulex (Crustacea: Amphipoda).

In a river survey, Gammarus pulex amphipods both unparasitised and parasitised with the acanthocephalan Echinorhynchus truttae were distributed similarly with respect to flow regimen, tending to be more abundant in faster, shallower, riffle patches. However, there was a higher prevalence of parasitism in faster, shallower areas than in slower, deeper areas and abundance correlated with macrophyte coverage for unparasitised but not parasitised amphipods, indicating subtle differences in habitat usage. A laboratory 'patch' simulation indicated that parasitism influenced micro-distribution. There were higher proportions of unparasitised amphipods in/under stone substrates and within weed. In contrast, there were higher proportions of parasitised amphipods in the water column and at the water surface. As the experiment progressed, unparasitised but not parasitised amphipod habitat usage shifted from those micro-habitats above the substrate and in the water column to those in/under the substrates. Experiments also demonstrated that parasitised amphipods were more active and had a greater preference for illumination. Previous studies of the effects of acanthocephalan parasitism of amphipod hosts have focussed on how drift behaviour is altered, now we show that subtle differences in micro-habitat usage could translate to greatly increased vulnerability to fish predation. We discuss how aggregation of parasitised individuals within specific habitats could promote parasite transmission.

Acanthocephala↗
PubMed2000

The cypris larvae of the parasitic barnacle Heterosaccus lunatus (Crustacea, Cirripedia, Rhizocephala): some laboratory observations.

Heterosaccus lunatus parasitizes the portunid crab, Charybdis callianassa in Moreton Bay, Australia. With the host crabs maintained at 22.5 degrees C this sacculinid rhizocephalan released larval broods every 6-7 days. During July-August 1996 and particularly August 1999 such broods showed the change-over from male only larvae in the early broods to females only in the later broods. As the host crabs were maintained under similar aquarium conditions in both years it is concluded that the light/dark cycle is the principal cue triggering this larval sex reversal. Oogenesis in the parasite externa is somehow controlled to produce two different sized ova - male larvae develop from large ova and females from small ova. A working hypothesis outlining how sex is probably determined for the larvae of sacculinids is erected. H. lunatus is considered the ideal sacculinid for the further experimental work necessary to verify the proposed sex-determining mechanism and its control processes. Measurements of the maximum swimming speeds of H. lunatus male and female cyprids showed the larger males to be the faster in absolute terms (27.95 compared with 17.60 mm s(-1), respectively), however, the calculated relative speeds were almost identical at approximately 90 body lengths s(-1). Settlement experiments confirmed that female H. lunatus cyprids settle only on the gills of C. callianassa; these cyprids needed to be at least 2 days old before they were able to settle.

Journal Article↗
PubMed2000

Upper thermal tolerances of the beachflea Orchestia gammarellus (Pallas) (Crustacea: Amphipoda: Talitridae) associated with hot springs in Iceland.

The upper thermal tolerance (CT(max)) of beachfleas Orchestia gammarellus (Pallas) collected from a number of different locations in Iceland was determined. Differences were recorded between field populations associated with thermal springs and those from non-thermal sites. A number of reciprocal acclimation experiments (where animals from thermal and non-thermal sites were acclimated to the measured ambient temperatures of thermal (17 and 22 degrees C) and non-thermal (11 degrees C) sites) were performed. Differences between at least one thermal population and a non-thermal population were maintained following this reciprocal acclimation, supporting the hypothesis that population differences were due to non-reversible genetic differences and not local acclimatisation. Animals from one thermal site (Reykjanes) had a mean CT(max)=37.1+/-0.5 degrees C when acclimated at 11 degrees C and 38.6+/-0.3 degrees C when acclimated at 22 degrees C, whereas animals from a non-thermal site (Hvassahraun) had CT(max) values of 35.9+/-0.5 and 37.9+/-0.3 degrees C, respectively. In other cases, differences are best explained by local acclimatisation. Results are discussed in relation to ambient local conditions and the degree of isolation of the different populations.

Journal Article↗
PubMed2001

Swimming behaviour in Monoporeia affinis (Crustacea: Amphipoda) - dependence on temperature and population density.

Swimming speed and swimming activity of the nocturnally active benthic amphipod Monoporeia affinis were measured in water temperatures from 3 to 18 degrees C and different population densities in the laboratory. Swimming speed increased with increasing temperature. Increasing water temperature reduced the percentage of active animals in the population, as measured by a "freeze frame" technique. At 7 and 10 degrees C a higher percentage of the population was active in higher animal densities. In all tested conditions swimming activity was highest at about 1 h after light-off and lowest shortly before the predicted time of light-on. The consequences of the documented behavioural responses to environmental stimuli are discussed in relation to population dynamics.

Journal Article↗
PubMed2001

Growth, oxygen consumption, ammonia-N excretion, biochemical composition and energy content of Farfantepenaeus paulensis Pérez-Farfante (Crustacea, Decapoda, Penaeidae) early postlarvae in different salinities.

Physiological responses of early postlarval shrimp Farfantepenaeus paulensis to different salinities were evaluated. Growth, net growth efficiency (K(2)), oxygen consumption, ammonia-N excretion, protein, lipid, carbohydrate, ash and energy content were determined in postlarval stages PL VI-VII and PL XIII-XV at 5 per thousand, 15 per thousand, 25 per thousand and 34 per thousand. PL VI-VII and PL XIII-XV correspond, in the wild, to the penetration of postlarvae into estuarine zones and the adoption of benthic habits, respectively. Postlarvae were gradually acclimated to the various salinity levels in the stage PL VI-VII and were maintained there until reaching the stage PL XIII-XV. Although development time was not affected by salinity, growth was decreased at 34 per thousand. Oxygen consumption was less affected by salinity while ammonia-N excretion presented a negative correlation with salinity. In both stages, protein content was lower at 34 per thousand. In PL VI-VII, lipid was decreased at 5 per thousand, while no significant difference in lipid content was observed in PL XIII-XV. Carbohydrate and ash levels did not vary in function of salinity levels. Energy content was reduced in PL XIII-XV at 34 per thousand. Net growth efficiency (K(2)) between PL VI-VII and PL XIII-XV presented higher values at 15 per thousand and 25 per thousand, and the lowest at 34 per thousand. Enhanced energy expenditure due to osmoregulation was not detected as denoted by oxygen consumption rates. Nitrogen metabolism seems to play a key role in maintaining body fluids concentration in relation to medium salinity. It is concluded that the high degree of euryhalinity in these stages of F. paulensis may be an adaptation to ontogenetic events such as migration to estuarine areas. For aquaculture purposes, it is recommended to maintain these postlarval stages at salinities between 15 per thousand and 25 per thousand rather than 34 per thousand.

Journal Article↗
PubMed2000

Elemental composition of Mysis mixta (Crustacea, Mysidacea) and energy costs of reproduction and embryogenesis under laboratory conditions.

Mysis mixta were reared under laboratory conditions (temperature: 9-10 degrees C; salinity: 7 per thousand, ad libitum food). Dry weight, ash, total carbon and nitrogen content of mysids (muscle tissue, eggs, and embryos of different developmental stages) have been analyzed. We found significant variations in ash content and elemental composition during growth and maturation for both sexes. The proportion of carbon in abdominal muscle decreased gradually from juveniles with body weight of 3-4 mg (42.9%) to males and gravid females ( approximately 40.0%). The nitrogen content was relatively constant (11.4% in average) with significant differences only between juveniles (11.3%) and mature females (11.6%). In embryos, carbon and nitrogen content were highest in early stages (58.6 and 14.3%, respectively). By the end of the marsupial development, carbon had decreased to 51.4% and nitrogen to 12.6%. The C:N ratio reflected the change in somatic carbon content, and the ratio decreased 6.2% from juveniles to gravid females, indicating lipids to be an energy source during maturation and reproduction. The weight-specific female investment in reproduction increases with body size. In gravid females, intersegmental growth during brooding period was observed, while males appear to store energy only for copulation and die after mating. Ontogenetic variation in body composition has implications for elemental budgets of M. mixta, its value as prey for fish and in modeling energy and nutrient cycling.

Journal Article↗
PubMed2000

Eye function of Mysidacea (Crustacea) in the northern Baltic Sea.

Eye spectral sensitivity, [S(lambda)], was measured in seven northern Baltic mysid species using an electroretinogram technique. Their S(lambda) curves were compared with the spectral distribution of underwater light at their normal habitats. In the littoral species Neomysis integer, Praunus flexuosus and Praunus inermis, the S(lambda) maxima, [S(lambda)(max)], were in the wavelength-bands of 525-535, 505-515 and 520-530 nm respectively. The neoimmigrant species Hemimysis anomala had a S(lambda)(max) around 500 nm and high sensitivity at 393 nm, possibly indicating UV-sensitivity. S(lambda) of the pelagic species Mysis mixta and Mysis relicta sp. II was at about 505-520 nm. M. relicta sp. I from Pojoviken Bay and fresh water humic Lake Pääjärvi had S(lambda)(max) at approximately 550 nm and 570 nm respectively. This is in accordance with a similar long-wavelength shift in light transmittance of the respective waters. The eyes of the latter population were also damaged by strong light. The pontocaspian neoimmigrant H. anomala is clearly adapted to waters transmitting more blue light.

Journal Article↗