Further studies of the effects of deprivation of sulfate on the early development of the sea urchin Paracentrotus lividus

Development ◽  
1965 ◽  
Vol 14 (3) ◽  
pp. 289-305
Author(s):  
J. Immers ◽  
J. Runnström

The morphological effects of sulfate-free medium on sea urchin embryos were described in detail by Herbst (1904). Further studies were carried out by Lindahl (1936, 1942). He was the first to consider metabolic aspects of the rôle of sulfate in the development of the sea urchin. Immers (1956, 1959, 1961a and b, 1962) studied the distribution and function of acid mucopolysaccharides in early developmental stages of sea urchins, mainly Paracentrotus lividus. A dominant group of these acid polysaccharides are sulfated. Their location in the blastocoel, in the hyaline layer and in the lumen of the intestine could be demonstrated by staining of sectioned specimens with the ferri-acetic reagent of Hale (1946). In blastulae or gastrulae raised in sulfate-free sea water these regions are negative with respect to Hale staining (Immers, 1961b). On the other hand, the ectodermal nuclei of the animal region of the embryos are stained with the Hale reagent although the nuclei of the vegetal region remained unstained (1.c.).

1953 ◽  
Vol 30 (4) ◽  
pp. 515-524
Author(s):  
J. M. MITCHISON

1. Chambers (1938) described an experiment in which he cut open one blasto-mere of a cleaving sea-urchin egg at the dumb-bell stage in isotonic KCl. The other blastomere contracted like a ‘deflating balloon’, and this has been taken by other workers as evidence of a positive membrane tension in the cleaving egg. This experiment has been repeated with other sea urchins in various media. It is concluded that this effect only takes place in one species of sea urchin, in an abnormal medium, and after it has suffered irreparable damage. It is not, therefore, legitimate to suppose that there is normally a positive membrane tension in a cleaving egg. It is found that eggs will continue to cleave with one blastomere in an irregular shape which indicates that, on the contrary, there is no membrane tension and no internal pressure. These are the conditions demanded by the ‘expanding membrane’ theory of cleavage. 2. It is found that the furrow of a cleaving egg will pass through a needle placed in its path. This result argues against a simple contracting ring in the furrow region being responsible for cleavage. 3. Chambers (1938) found that an egg will continue to cleave when its asters have been destroyed by stirring. This result has been confirmed by a similar experiment on a different species of sea urchin. This is crucial evidence against an astral mechanism of cleavage. 4. The effects of compressing cleaving eggs have been studied. It is found that compressed eggs continue to cleave unless the degree of flattening is considerable; that cleavage is delayed before it is finally stopped; and that eggs in Ca-free sea water are more susceptible to compression than eggs in ordinary sea water. These results are consistent with the ‘expanding membrane’ theory.


1964 ◽  
Vol 22 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Peter Perlmann ◽  
Jane Couffer-Kaltenbach

Homogenates of fertilized eggs of the sea urchin Paracentrotus lividus were fractionated by differential centrifugation. In addition, whole eggs were fragmented, on a preparative scale, by centrifugation in sea water-sucrose gradients. The fractions and fragments were subsequently assayed for their content of soluble protein antigens described in an earlier publication. Relative concentrations of antigen present in quantitatively isolated cell fractions were estimated by graded antiserum absorption in combination with agar-diffusion technique. Two of six antigens were found to be associated mainly with the low speed sediments. Treatment of the various sediments with hypotonic medium and results obtained with fragmented eggs suggested that these two antigens and possibly a third were probably located in the yolk granules. The other antigens were more evenly distributed among the low speed sediments and the non-sedimented part of the cytoplasm. Only one of the antigens was consistently associated with the microsomal fraction.


2016 ◽  
Vol 115 ◽  
pp. 11-19 ◽  
Author(s):  
Silvia Morgana ◽  
Chiara Gambardella ◽  
Carla Falugi ◽  
Roberto Pronzato ◽  
Francesca Garaventa ◽  
...  

2008 ◽  
Vol 65 (2) ◽  
pp. 132-139 ◽  
Author(s):  
Dina Soualili ◽  
Philippe Dubois ◽  
Pol Gosselin ◽  
Philippe Pernet ◽  
Monique Guillou

Abstract Soualili, D., Dubois, P., Gosselin, P., Pernet, P., and Guillou, M. 2008 Assessment of seawater pollution by heavy metals in the neighbourhood of Algiers: use of the sea urchin, Paracentrotus lividus, as a bioindicator. – ICES Journal of Marine Science, 65: 132–139. The objective of the study was to assess the levels of contamination by heavy metals near the Algiers metropolis, using a combination of chemical and toxicological data gained from analyses of sediments and biological parameters characteristic of the sea urchin, Paracentrotus lividus. Zinc, lead, cadmium, copper, and iron concentrations were determined in sediments and in sea urchin gonads. Sediment toxicity was assessed by bioassay based on the larval development of sea urchins. The most numerous larval abnormalities were found in a site near Algiers identified as highly polluted by lead. The levels of the other metals across the study area fell within the background concentrations reported in the literature for the Mediterranean Sea, with the exception of zinc, which showed high values in female gonads.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Cinzia Corinaldesi ◽  
Elisabetta Damiani ◽  
Francesca Marcellini ◽  
Carla Falugi ◽  
Luca Tiano ◽  
...  

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 638
Author(s):  
Monika Mazur ◽  
Daria Wojciechowska ◽  
Ewa Sitkiewicz ◽  
Agata Malinowska ◽  
Bianka Świderska ◽  
...  

The slime mold Dictyostelium discoideum’s life cycle includes different unicellular and multicellular stages that provide a convenient model for research concerning intracellular and intercellular mechanisms influencing mitochondria’s structure and function. We aim to determine the differences between the mitochondria isolated from the slime mold regarding its early developmental stages induced by starvation, namely the unicellular (U), aggregation (A) and streams (S) stages, at the bioenergetic and proteome levels. We measured the oxygen consumption of intact cells using the Clarke electrode and observed a distinct decrease in mitochondrial coupling capacity for stage S cells and a decrease in mitochondrial coupling efficiency for stage A and S cells. We also found changes in spare respiratory capacity. We performed a wide comparative proteomic study. During the transition from the unicellular stage to the multicellular stage, important proteomic differences occurred in stages A and S relating to the proteins of the main mitochondrial functional groups, showing characteristic tendencies that could be associated with their ongoing adaptation to starvation following cell reprogramming during the switch to gluconeogenesis. We suggest that the main mitochondrial processes are downregulated during the early developmental stages, although this needs to be verified by extending analogous studies to the next slime mold life cycle stages.


1951 ◽  
Vol 34 (3) ◽  
pp. 285-293 ◽  
Author(s):  
Anna Monroy Oddo ◽  
Maria Esposito

In the eggs of Arbacia lixula and Paracentrotus lividus an uptake of K occurs during the first 10 minutes following fertilization. Between 10 and 40 minutes K is then released. Both in Arbacia and in Paracentrotus the minimum point of the curve coincides with the nuclear streak stage. A maximum loss of 25 per cent in Arbacia and 20 per cent in Paracentrotus with respect to the amount present in the unfertilized eggs has been found. From 40 minutes up to 1 hour K undergoes a further increase and when the first cleavage sets in the same amount of K is present as in the unfertilized eggs. By treating the eggs with K-free artificial sea water it has been established that about 60 per cent of the K content of the eggs is in a non-diffusible condition. Also under such conditions the eggs when fertilized are able to take up even the very small amount of K present in the medium that was released by them prior to fertilization.


2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.


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