Teratogenic effect of tolbutamide on the development of the sea urchin embryo (Paracentrotus lividus lamarck)

Summary The hypoglycemic agent tolbutamide was tested for its action on the cleavage and differentiation of the sea urchin embryo. Tolbutamide effects a strong selective action on the endoderm which becomes suppressed.     

Evidence for a novel cytoplasmic processing event in ribosome maturation in the sea urchin Paracentrotus lividus

In this paper we demonstrate the existence of a cytoplasmic processing step, never before described, involving both the pre-ribosomal subunits in the sea urchin Paracentrotus lividus. Northern-blot hybridization, primer extension, S1 mapping experiments and in situ hybridizations allowed us to demonstrate that cytoplasmic processed particles are successively re-imported into the nucleus where maturation of their RNAs is completed prior to being exported to the cytoplasm. Our findings lead to the proposal of a new model of ribosome maturation and shuttling.     

Effect of 2 inhibitors of glycoprotein synthesis, tunicamycin and 2-deoxyglucose, on development of the sea urchin (Paracentrotus lividus) egg]

Tunicamycin, an inhibitor of glycoprotein synthesis, inhibits the development of the sea Urchin egg. Gastrulation is very sensitive to the Tunicamycin. Fertilization is not inhibited. 2-deoxy-D-glucose inhibits gastrulation and induces the hyperdevelopment of ectodermic structures.     

Phosphoproteinphosphatase activity in sea urchin embryos

Riassunto Si è studiata l'attività fosfoproteinfosfatasica in omogenati totali di uova ed embrioni diParacentrotus lividus e diArbacia lixula. La reazione ha un optimum a pH acido, è stimolata da K⁺ e Na⁺ ed è inibita da Ca⁺⁺ e Mg⁺⁺. L'attività enzimatica aumenta tra la fecondazione e lo stadio a 64 blastomeri; in seguito rimane costante fino a blastula con mesenchima; quindi generalmente decresce.

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This work has been supported by a grant from the Consiglio Nazionale delle Ricerche to the Laboratory of Comparative Anatomy (Research Group of Embryology).     

The distribution of mitochondria in sea urchin embryos

Zusammenfassung Zytologische Untersuchungen an Embryonen von zwei Seeigelarten haben in bezug auf die Lokalisation der Mitochondrien keinen Unterschied zwischen animaler und vegetativer Hemisphäre ergeben. Vorläufige Versuche, mit Hilfe einer quantitativen Methode die Mitochondrien in Homogenaten zu zählen, ergaben eine starke Zunahme auf dem Stadium der Blastula und eine anschliessende Abnahme der Mitochondrienzahl pro Embryo.

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Research supported by the National Cancer Institute, National Institutes of Health, United States Public Health Service.     

Reaction step requiring protein synthesis in DNA synthesis in sea urchin embryos

Summary In the acid-soluble fraction extracted from embryos treated with cycloheximide, thymidine triphosphate was largely accumulated and DNA polymerase activity decreased, while both activities of thymidine kinase and thymidylate kinase remained unchanged.     

Delay of normal development of sea urchin embryos by cytosine arabinoside

Résumé Le développement des ufs d'oursins est ralenti par la cytosine arabinoside à laquelle on les expose pendant 4 à 8 h, mais il reprend son cours après le traitement.

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This research was performed at the Naples Zoological Station in August of 1965 and was supported by an American Table award from the American Institute of Biological Sciences. I wish to thank Dr.A. Orengo for his kind assistance during my stay at the Station and to the director,P. Dohrn, for his hospitality.     

Aggregation of cells isolated from vegetalized and animalized sea urchin embryos

Riassunto Blastule diParacentrotus lividus trattate con LiCl (vegetalizzate) o con ZnSO₄ (animalizzate) sono state disaggregate con la tecnica precedentemente descritta.Le cellule da blastule vegetalizzate si riaggregano in masse solide che non differenziano nè scheletro nè intestino. Quelle da blastule animalizzate danno origine a vescicole ciliate. Tentativi di combinazione di cellule da blastule animalizzate e vegetalizzate in un caso hanno dato origine ad aggregati con abbozzi di scheletro.     

The binding of organic mercurials by normal and sucrose-swollen embryos of the sea urchinParacentrotus lividus

Résumé En vue d'étudier les effets d'une tension intercellulaire sur les groupes sulfhydriles à la surface des blastomères, nous fîmes subir aux blastules d'oursin un gonflement osmotique, en les traitant au sucrose. Les embryons enflés absorbèrent ensuite autant de réactif mercuriel que les embryons normaux. Nous en déduisons que les groupes sulfhydriles superficiels ne sont pas influencés par les forces osmotiques qui déforment les parois des embryons.     

Satellite DNA (II) from sea urchin (Lytechinus variegatus) sperm

When DNA isolated from freshly collected sperm of sea urchin (Lytechinus variegatus) is centrifuged to equilibrium in CsCl, 2 heavy satellite bands appear beside the main band DNA. Satellite DNA (II) appears in between the main band DNA (rho = 1.695 g/cm3) and the rDNA satellite (rho = 1.722 g/cm3). Satellite DNA (II) has a buoyant density 1.710 g/cm3, corresponding to 50% GC content. It is speculated that the satellite DNA (II), which appears to be of high mol. wt, might contain the sequences complementary to histone mRNA.     

Satellite DNA (II) from sea urchin (Lytechinus variegatus) sperm

Summary When DNA isolated from freshly collected sperm of sea urchin (Lytechinus variegatus) is centrifuged to equilibrium in CsCl, 2 heavy satellite bands appear beside the main band DNA. Satellite DNA (II) appears in between the main band DNA (=1.695 g/cm³) and the rDNA satellite (=1.722 g/cm³). Satellite DNA (II) has a buoyant density 1.710 g/cm³, corresponding to 50% GC content. It is speculated that the satellite DNA (II), which appears to be of high mol.wt, might contain the sequences complementary to histone mRNA.Acknowledgment. This work was carried out in the laboratory of Dr D. W. Stafford, Department of Zoology, University of North Carolina, Chapel Hill, N.C., USA. I thank him for his help and cooperation.