Search results for "Arbacia"
showing 10 items of 30 documents
Impact of sewage pollution on two species of sea urchins in the Mediterranean Sea (Cortiou, France): radial asymmetry as a bioindicator of stress.
2015
9 pages; International audience; BackgroundThe surroundings of the Cortiou sewage are among the most polluted environments of the French Mediterranean Sea (Marseilles, France). So far, no studies have precisely quantified the impact of pollution on the development of organisms in this area.MethodsWe used a fluctuating asymmetry (FA) measure of developmental instability (DI) to assess environmental stress in two species of radially symmetric sea urchins (Arbacia lixula and Paracentrotus lividus). For six sampling sites (Cortiou, Riou, Maire, East Maire, Mejean, and Niolon), levels of FA were calculated from continuous and discrete skeletal measures of ambulacral length, number of pore pairs …
Size-dependent predation of the mesopredator Marthasterias glacialis (L.) (Asteroidea)
2016
Asteroids are largely recognized as important predators in all of the world’s oceans and for this reason, they play a crucial role in shaping the structure and functioning of benthic ecosystems. The spiny starfish Marthasterias glacialis is generally considered a voracious predator of molluscs, in particular bivalves. Using field observations and carbon (δ13C) and nitrogen (δ15N) stable isotopes, we explored possible changes in diet in relation to size of M. glacialis. Data were collected at Ustica Island (Southern Tyrrhenian Sea) from June 2008 to June 2010. M. glacialis showed a size shift in feeding preferences due to different use of food items: bivalves, Columbella rustica, Euthria cor…
Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758)
2020
Marine life is extremely sensitive to the effects of environmental noise due to its reliance on underwater sounds for basic life functions, such as searching for food and mating. However, the effects on invertebrate species are not yet fully understood. The aim of this study was to determine the biochemical responses of Arbacia lixula exposed to high-frequency noise. Protein concentration, enzyme activity (esterase, phosphatase and peroxidase) and cytotoxicity in coelomic fluid were compared in individuals exposed for three hours to consecutive linear sweeps of 100 to 200 kHz lasting 1 s, and control specimens. Sound pressure levels ranged between 145 and 160 dB re 1μPa. Coelomic fluid was …
Leading role of the sea urchin Arbacia lixula in maintaining the barren state in southwestern Mediterranean
2011
Sympatric sea urchin species are usually considered to belong to the same grazer guild. Nevertheless, their role in community dynamics may vary due to species-specific morphological traits, feeding preferences and foraging behavior. In the Mediterranean Sea, the two species Paracentrotus lividus and Arbacia lixula co-occur in barren areas. Whereas P. lividus is usually considered responsible for creating a barren ground, the roles of the two sea urchin species in its maintenance are currently unclear. The relative and combined effects of P. lividus and A. lixula on maintaining the benthic community in the barren state were tested experimentally, using orthogonal exclusion of the two species…
Morphological response of the larvae of Arbacia lixula to near-future ocean warming and acidification
2017
The distribution of the sea urchin Arbacia lixula, a warm affinity species, has been expanding in the Mediterranean Sea. To address questions on potential for future success of this species in the region, the thermotolerance of larval development was investigated in context of regional warming. The larvae were reared in present day spawning period (20 °C) and warming conditions (+4 = 24 and +6 = 26 °C). As the calcifying larvae of sea urchins are vulnerable to stunted growth caused by ocean acidification, the impact of lower pH (−0.3 pH units) on larval development was also investigated in combination with warming. Morphological traits of the larvae, post-oral length arms, overall length of…
Effects of magnesium deprivation on development and biomineralization in the sea urchin Arbacia lixula
2019
Echinoderms have an extensive endoskeleton composed of magnesian calcite and occluded matrix proteins. As biomineralization in sea urchin larvae is sensitive to the Magnesium:Calcium ratio of seawater, we investigated the effects of magnesium deprivation on development and skeletogenesis in the sea urchin Arbacia lixula. We focused on the localization of the skeletogenic cells (primary mesenchyme cells) and the spatial expression of associated genes. Embryos reared in Mg-free seawater exhibited developmental delay from 6-h post-fertilization and at 24 h embryos showed complete lack of biomineral formation. Larvae (48–72 h) exhibited severe skeleton malformations. Fluorescent labelling revea…
Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.
2016
Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species…
Characterization of the Teeth Skeletal Matrix from <i>Arbacia lixula</i>
2016
The teeth of sea urchins are highly complex composite structures, composed predominantly of high magnesium calcite, and of a minor heterogeneous assemblage of organic macromolecules that are occluded within the mineral. The organic matrix fulfils important functions in mineralization, in addition to giving the mineral phase peculiar mechanical properties, different from that of purely inorganic calcite. Nevertheless, the composition and function of individual components of the organic matrix still remains largely unknown. Up to now, the detailed protein repertoire of teeth from a single sea urchin species (Strongylocentrotus purpuratus, order Camarodonta) was investigated. In this study, we…
Role of two co-occurring Mediterranean sea urchins in the formation of barren from Cystoseira canopy
2015
Abstract In the Mediterranean Sea the co-occurring sea urchins Paracentrotus lividus and Arbacia lixula are usually considered to share the same ecological role in the formation of barren from Cystoseira canopy. However, their foraging ability may vary due to feeding behavior and species-specific morphological traits. The relative effects of P. lividus and A. lixula on Cystoseira canopy was tested experimentally both in the laboratory, at a density of about 20 ind./m 2 , and in the field by gut content analysis. Field and laboratory results show that A. lixula is unable to affect Cystoseira spp. Furthermore, these results confirmed the great ability of P. lividus to consume Cystoseira canop…
Cell-Free Coelomic Fluid Extracts of the Sea Urchin Arbacia lixula Impair Mitochondrial Potential and Cell Cycle Distribution and Stimulate Reactive …
2020
Triple-negative breast cancer (TNBC) is a highly malignant tumor histotype which lacks effective targeted therapies, thereby being considered as the most aggressive form of breast carcinoma. To identify novel compounds which could counteract TNBC cell growth, we explored the in vitro effects of crude extracts and <