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At least 19 recordsLinked to original sources
PubMed2006

Cardiovascular effects of Nemopilema nomurai (Scyphozoa: Rhizostomeae) jellyfish venom in rats.

Over the past few years, populations of the giant jellyfish Nemopilema nomurai (Scyphozoa: Rhizostomeae) have increased dramatically in the waters of China, Korea, and Japan without any definitive reason. This has resulted in severe damage to fisheries in the areas. During a pilot study, we observed that the venom of N. nomurai produced a functional cardiac depression in mice. However, the mechanism of action was not examined. In the present study, we investigated the cardiovascular effects of nematocyst-derived venom from N. nomurai in anesthetized rats. Venom (0.1-2.4 mg protein/kg, i.v.) produced dose-dependent hypotension (65+/-12% of initial at a cumulative dose of 3 mg/kg) and bradycardia (80+/-5% of initial at a cumulative dose of 3 mg/kg). At the highest dose, this was characterized by a transient decrease in blood pressure (phase 1) followed by a return to basal level and then a slower decrease in blood pressure (phase 2). Venom also produced a decrease in rate and force of contraction in the rat isolated atria. Interestingly, venom induced a contraction of isolated aortic rings which was blocked by felodipine but not by prazosin, suggesting the contraction is mediated by calcium channel activation. These results suggest that the negative inotropic and chronotropic effects of the venom of N. nomurai may be due to a direct effect on the heart.

Animals↗
PubMedDate not supplied

[Shape conservatism and shaping variability. The comparative analysis of Hydrozoa and Scyphozoa early development].

The morphogenetic pathways based on the self-organization take an important part in the early development of White Sea Cnidarians--Dynamena pumila (Hydrozoa) and Aurelia aurita (Scyphozoa). Comparative analysis of their early development revealed two patterns of embryonic spatial structure reproduced in the morphogenesis of both species in spite of the differences of morphogenetic paths. These are toroidal and bilaterally symmetrical shapes. It is possible that these shapes correspond to the equilibrium states of developing system and their stable reproduction is a result of epigenetic rather than genetic program.

Animals↗
PubMed2006

Mitochondrial genome of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa): A linear DNA molecule encoding a putative DNA-dependent DNA polymerase.

The 16,937-nuceotide sequence of the linear mitochondrial DNA (mt-DNA) molecule of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa) - the first mtDNA sequence from the class Scypozoa and the first sequence of a linear mtDNA from Metazoa - has been determined. This sequence contains genes for 13 energy pathway proteins, small and large subunit rRNAs, and methionine and tryptophan tRNAs. In addition, two open reading frames of 324 and 969 base pairs in length have been found. The deduced amino-acid sequence of one of them, ORF969, displays extensive sequence similarity with the polymerase [but not the exonuclease] domain of family B DNA polymerases, and this ORF has been tentatively identified as dnab. This is the first report of dnab in animal mtDNA. The genes in A. aurita mtDNA are arranged in two clusters with opposite transcriptional polarities; transcription proceeding toward the ends of the molecule. The determined sequences at the ends of the molecule are nearly identical but inverted and lack any obvious potential secondary structures or telomere-like repeat elements. The acquisition of mitochondrial genomic data for the second class of Cnidaria allows us to reconstruct characteristic features of mitochondrial evolution in this animal phylum.

Amino Acid Sequence↗
PubMed1984

Heat shock proteins in Aurelia (Cnidaria, Scyphozoa).

Heat shock proteins (hsp) in Aurelia identified by one-dimensional SDS-PAGE are of sizes 93,83,70,68,45, and 39 kD, the most rapidly labeled being hsp 70 in all developmental stages. Labeled hsp in the polyp are found mostly in the epidermis; gastrodermal nuclei are also labeled. The minimum temperature for induction of the proteins is about the same (27 degrees to 28 degrees C), regardless of whether polyps have been cultured at 15 degrees or 24 degrees C. Adults and planulae taken from natural water at 28 degrees C do not show accumulation of hsp 70. Induction of strobilation by raising polyps from 15 degrees to 25 degrees C is not associated with appreciable labeling of hsp. Polyps transferred to higher or lower salinity have decreased protein synthesis but do not synthesize stress proteins.

Animals↗
PubMed2003

An endogenous peptide is involved in internal control of metamorphosis in the marine invertebrate Cassiopea xamachana (Cnidaria: Scyphozoa).

In the metagenetic life-cycle of the scyphozoan Cassiopea xamachana metamorphosis of planula-larvae or larva-like buds to polyps is triggered by specific external cues which are transmitted inside the larva or bud where internal signals finally coordinate the initiation of metamorphosis. This study deals with an endogenous metamorphosis inducer present in planulae and buds of Cassiopea. The inductive cue is localized in the basal part of the buds and can be characterized as a peptide with an apparent molecular weight of about 7,000 Da. Further purification was performed via reversed phase HPLC on a C18 column. Additional inhibitor assays revealed that protein kinase C and PI3 kinase, two known elements of the metamorphosis-inducing signal transduction cascade in Cassiopea, may act downstream of the endogenous inducing peptide.

Androstadienes↗
PubMed2003

Control of head morphogenesis in an invertebrate asexually produced larva-like bud ( Cassiopea andromeda; Cnidaria: Scyphozoa).

Scyphopolyps of Cassiopea andromeda propagate asexually by forming larva-like buds which separate from the parent in a developmentally quiescent state. These buds metamorphose into sessile polyps when exposed to specific biogenic, chemical inducers. Morphogenesis of transversely dissected buds indicates the presence of pattern-determining signals; whereas the basal bud fragments may still form a complete scyphistoma the apical bud fragments develop spontaneously in the absence of an inducer into a polyp head without stalk and foot. Based on these findings Neumann (dissertation, Cologne University, 1980) postulated a head-inhibiting signal which is released at the basal pole and inhibits head formation at the apical end. Contrary to this hypothesis dissection itself might induce the development of head structures. The present study deals with the control of polyp head formation in C. andromeda. It concentrates on two points, namely the postulated head inhibitor and the involvement of compounds known to act during metamorphosis (the enzyme protein kinase C and the specific metamorphosis inducer Z-GPGGPA). We found that compared to intact buds and apical bud fragments transversely incised buds reached an intermediate stage of head development. This confirms Neumann's hypothesis. Consequently we focused on the mode of action and the chemical nature of the head-inhibiting signal in C. andromeda. Our results indicate that the head inhibitor may be included in one of six pooled fractions isolated from bud homogenate via gel filtration on a Sephadex G-50 column. The inhibitor is supposed to be water-soluble and to have a molecular weight of 850-1,500 Da. Furthermore we prove that head formation is not promoted by the metamorphosis-inducer Z-GPGGPA but is prevented by the inhibitors psychosine, chelerythrine and RO-32-0432 showing the involvement of protein kinase C in this process.

Alkaloids↗
PubMed2003

Sterile polystyrene culture dishes induce transformation of polyps into medusae in Aurelia aurita (Scyphozoa, Cnidaria).

Polyps of Aurelia aurita produce medusae once a year. Under laboratory conditions this process, termed strobilation, can be induced by lowering the incubation temperature for about two weeks. Here we report a fast induction of strobilation by sterile polystyrene culture dishes. The effect is abolished when the culture dishes are washed twice with hot water prior to the experiment. We recommend that polystyrene cultureware should be pre-washed whenever there is an indication of unusual effects.

Animals↗
PubMed2005

A newly discovered oxidant defence system and its involvement in the development of Aurelia aurita (Scyphozoa, Cnidaria): reactive oxygen species and elemental iodine control medusa formation.

In Aurelia aurita, applied iodine induces medusa formation (strobilation). This process also occurs when the temperature is lowered. This was found to increase oxidative stress resulting in an increased production of iodine from iodide. One polyp produces several medusae (initially termed ephyrae) starting at the polyp's oral end. The spreading of strobilation down the body column is controlled by a feedback loop: ephyra anlagen decrease the tyrosine content in adjacent polyp tissue by producing melanin from tyrosine. Endogenous tyrosine is able to remove iodine by forming iodiferous tyrosine compounds. The reduced level of tyrosine causes the ephyra-polyp-border to move towards the basal end of the former polyp. We argue that an oxidant defence system may exist which makes use of iodide and tyrosine. Like other marine invertebrates, polyps of Aurelia contain iodide ions. Inevitably produced peroxides oxidise iodide into iodine. The danger to be harmed by iodine is strongly decreased by endogenous tyrosine which reacts with iodine to form iodiferous tyrosine compounds including thyroxin. Both substances together, iodide and tyrosine, form an efficient oxidant defence system which shields the tissue against damage by reactive oxygen species. In the course of evolution (from a species at the basis of the animal kingdom like Aurelia to a highly evolved species like man) the waste product thyroxin (indicating a high metabolic rate) has developed into a hormone which controls the metabolic rate.

Animals↗
PubMed2001

Systematics and biogeography of the jellyfish Aurelia labiata (Cnidaria: Scyphozoa).

The hypothesis that the common eastern North Pacific Aurelia is A. aurita is falsified with morphological analysis. The name Aurelia labiata is resurrected, and the species is redescribed, to refer to medusae differing from A. aurita by a suite of characters related to a broad and elongated manubrium. Specifically, the oral arms are short, separated by and arising from the base of the fleshy manubrium, and the planulae are brooded upon the manubrium itself, rather than on the oral arms. Aurelia aurita possesses no corresponding enlarged structure. Furthermore, the number of radial canals is typically much greater in A. labiata, and thus the canals often appear more anastomosed than in A. aurita. Finally, most A. labiata medusae possess a 16-scalloped bell margin, whereas the margin is 8-scalloped in most A. aurita. Separation of the two forms has previously been noted on the basis of allozyme and isozyme analyses and on the histology of the neuromuscular system. Partial 18S rDNA sequencing corroborates these findings. Three distinct morphotypes of A. labiata, corresponding to separate marine bioprovinces, have been identified among 17 populations from San Diego, California, to Prince William Sound, Alaska. The long-undisputed species A. limbata may be simply a color morph of A. labiata, or a species within a yet-unelaborated A. labiata species complex. The first known introduction of Aurelia cf. aurita into southern California waters is documented. Although traditional jellyfish taxonomy tends to recognize many species as cosmopolitan or nearly so, these results indicate that coastal species, such as A. labiata, may experience rapid divergence among isolated populations, and that the taxonomy of such species should therefore be scrutinized with special care.

Animals↗
PubMed2000

Induction of segmentation in polyps of Aurelia aurita (Scyphozoa, Cnidaria) into medusae and formation of mirror-image medusa anlagen.

Polyps of Aurelia aurita can transform into several medusae (jellyfish) in a process of sequential subdivision. During this transformation, two processes take place which are well known to play a key role in the formation of various higher metazoa: segmentation and metamorphosis. In order to compare these processes in bilaterians and cnidarians we studied the control and the kinetics of these processes in Aurelia aurita. Segmentation and metamorphosis visibly start at the polyp's head and proceed down the body column but do not reach the basal disc. The small piece of polyp which remains will develop into a new polyp. The commitment to the medusa stage moves down the body column and precedes the visible onset of segmentation by about one day. Segmentation and metamorphosis can start at the cut surface of transversely cut body columns, leading to a mirror-image pattern of sequentially developing medusae.

Animals↗
PubMedDate not supplied

Variations of ATP content in V79 cells treated with crude toxins of--Aequorea aequorea (Cnidaria: Hydrozoa) and Rhizostoma pulmo (Cnidaria: Scyphozoa). A preliminary study.

The toxicity of Cnidaria exerts a noticeable influence on some human activities, such as fishery and bathing, and on public health. As toxins of Mediterranean Cnidaria are located in nematocysts and in tissues, in this study the influence of crude toxins (nematocyst and surrounding tissue venom) extracted from the jellyfish Aequorea aequorea and Rhizostoma pulmo on ATP content of cultured V79 cells was assessed. Using the crude toxin of A. aequorea an increase of ATP levels in treated cells was noted; highest values (41.2 10(-7) mM/ml after 180 min treatment) were reached using the highest dose. Otherwise, a generalized decrease of ATP levels was observed treating cells with crude toxin of R. pulmo; recorded values showed the complete depletion of cell ATP at 115 min treatment with the highest dose. A statistical significance was recorded between treatment times and between doses using crude toxin of R. pulmo, and only between treatment times for A. aequorea.

Adenosine Triphosphate↗
PubMedDate not supplied

A fast centrifuge method for nematocyst isolation from Pelagia noctiluca Forskal (Cnidaria: Scyphozoa).

Nematocyst isolation from surrounding tissue is an important step to characterize Cnidarian venom. Although several protocols have been used to extract venoms from cnidarian tissues, the complete isolation of nematocysts from tissue is still difficult. The goal of the present work was to evaluate the effectiveness of three different media, Percoll, Ficoll and Methylcellulose in isolating nematocysts from Pelagia noctiluca tentacles by centrifugation. The complete sedimentation of nematocysts and tissue fragments to the bottom of the test tubes was observed in Ficoll and Methylcellulose suspensions. The best result was obtained using a discontinuous density gradient of Percoll: three types of nematocysts were concentrated in three different fractions along the density gradient. Protein assay and preliminary chromatographic analyses confirmed these results.

Animal Structures↗
PubMed1985

Dissociation and reaggregation of cells of Chrysaora quinquecirrha (Cnidaria, Scyphozoa).

Cells of scyphistomae, strobilae, and ephyrae were dissociated with trypsin and reaggregated. Clumping was inhibited in low Ca++ and by puromycin, but not by collagenase or sugars. Reaggregates from the oral end of the polyp developed tentacles and mouths first and basal structures later, whereas the opposite sequence occurred with cells from the lower gastric region. Nile-blue-stained cells from hypostome or peduncle did not form specific structures in the reconstructed polyp, but were distributed throughout the animal. Ephyra cell aggregates showed little morphogenesis, whereas cells from presumptive ephyra tissue gave rise to structures with tentacles and multiple oral openings. Mixed reaggregates containing equal proportions of polyp and ephyra cells formed irregular structures with transparent outer layer and opaque inner cell mass, suggesting stage-specific sorting.

Animals↗
PubMed2002

Cytotoxicity of the venom of Pelagia noctiluca forskål (Cnidaria: Scyphozoa).

The activity of Pelagia noctiluca venom was never assessed on cultured cells; therefore, we have evaluated on V79 cells the cytotoxicity, genotoxicity and ATP depletion induced after treatment. Venom did not cause alteration on cell DNA, but showed remarkable cytotoxic properties. With the highest nematocyst concentration (150,000 nematocyst/ml) 74 and 39% cells survived after 1 and 3 h, respectively, when evaluated by Trypan blue. Treated cells showed increased ATP levels during the same time. Preliminary HPLC analyses have showed the occurrence of a protein containing peak.

Adenosine Triphosphate↗