Search results for "sea urchin."
showing 10 items of 317 documents
On a glycoprotein of the sea urchin eggs and its changes following fertilization.
1960
Sbattendo con etere la frazione solubile in acido tricloroacetico di uova vergini diParacentrotus lividus si forma un precipitato all'interfacie tra etere e fase acquosa. L'analisi di questo precipitato ha dimostrato che si tratta di una glicoproteina. Il precipitato non si forma da estratti di uova fecondate.
In vitro incorporation of amino acids into proteins stimulated by RNA from unfertilized sea urchin eggs.
1964
Symmetry Breaking and Establishment of Dorsal/Ventral Polarity in the Early Sea Urchin Embryo
2015
The mechanisms imposing the Dorsal/Ventral (DV) polarity of the early sea urchin embryo consist of a combination of inherited maternal information and inductive interactions among blastomeres. Old and recent studies suggest that a key molecular landmark of DV polarization is the expression of nodal on the future ventral side, in apparent contrast with other metazoan embryos, where nodal is expressed dorsally. A subtle maternally-inherited redox anisotropy, plus some maternal factors such as SoxB1, Univin, and p38-MAPK have been identified as inputs driving the spatially asymmetric transcription of nodal. However, all the mentioned factors are broadly distributed in the embryo as early as no…
Homeobox genes and sea urchin development.
2000
We describe the expression of three Paracentrotus lividus homeobox-containing genes of the dispersed class during sea urchin embryogenesis and discuss their possible roles in the mechanisms of cell specification and embryo morphogenesis. PIHbox12 represents the first regulator identified in sea urchin that belongs to the zygotic class of transcription factors. Its early and transient expression and the localization of transcripts suggests that PIHbox12 is involved in cell fate specification of the oral or aboral ectodermal territories at the early cleavage stages. PIHbox9 is expressed just after the completion of gastrulation in a narrow stripe of cells at the ectoderm-endoderm boundary. It…
Spatial distribution of two maternal messengers encoding two sea urchin cell surface proteins
1993
We have localized, byin situ hybridization, two messengers, called bepl and bep4 (butanol extracted proteins), coding for cell surface proteins, involved in cell interaction, in sections of eggs of the sea urchinP. lividus. These maternal RNAs are spatially distributed in a gradient with a maximum at one pole of the egg. These results represent the first demonstration of the existence of a gradient of informational molecules in the sea urchin egg,i.e., the biological material for which the gradient theory was first proposed.
Marine Invertebrates as Bioindicators of Heavy Metal Pollution
2014
Atmosphere, earth and water compose the environment. The presence of heavy metals in the environment has grown because of their large employment in some industrial and agricultural activities. Although these metals are terrestrial products, they flow into the sea through effluents and sewage or are directly discharged from industries placed on the seawater front. It should be considered that metals concentrations vary widely according to different seawater latitudes and depths and can be strongly influenced by fresh water discharges from heavily polluted rivers. In this review recent studies on heavy metal pollution in marine ecosystems and their organisms will be presented. Metal speciatio…
Cadmium stress effects indicating marine pollution in different species of sea urchin employed as environmental bioindicators
2019
In recent years, researches about the defense strategies induced by cadmium stress have greatly increased, invading several fields of scientific research. Mechanisms of cadmium-induced toxicity continue to be of interest for researchers given its ubiquitous nature and environmental distribution, where it often plays the role of pollutant for numerous organisms. The presence in the environment of this heavy metal has been constantly increasing because of its large employment in several industrial and agricultural activities. Cadmium does not have any biological role and, since it cannot be degraded by living organisms, it is irreversibly accumulated into cells, interacting with cellular comp…
Sea urchin embryos exposed to cadmium as an experimental model for studying the relationship between autophagy and apoptosis
2014
The sea urchin embryo is a suitable model that offers an excellent opportunity to investigate different defence strategies activated in stress conditions. We previously showed that cadmium accumulates in a dose- and time-dependent manner into embryonic cells, activating different stress and defence mechanisms, including the synthesis of HSPs and the onset of apoptosis and/or autophagy. In this paper we investigated the functional relationship between autophagy and apoptosis, evaluating apoptosis signals in cadmium-exposed Paracentrotus lividus embryos with inhibited autophagy. We found that the inhibition of autophagy produced the concurrent reduction of apoptosis, suggesting that the two p…
Cell cooperation in coelomocyte cytotoxic activity of Paracentrotus lividus coelomocytes
2007
The coelomic fluid from the sea urchin Paracentrotus lividus contains several coelomocyte types including amoebocytes and uncoloured spherulocytes involved in immune defences. In the present paper, we show a Ca(2+)-dependent cytotoxic activity for the unfractionated coelomocytes assayed in vitro, with rabbit erythrocytes and the K562 tumour cell line. In a plaque-forming assay, whole coelomocyte preparations as well as density gradient separated coelomocyte populations revealed that cell populations enriched in uncoloured spherulocytes, exerted high cytotoxic activity by releasing lysins in the presence of amoebocytes. This cooperative effect could be dependent on soluble factors released b…