University of Nice Sophia Antipolis

About: University of Nice Sophia Antipolis is a education organization based out in Nice, France. It is known for research contribution in the topics: Population & Stars. The organization has 10291 authors who have published 19964 publications receiving 680762 citations. The organization is also known as: UNS & University of Nice-Sophia Antipolis.

Two growth factor signalling pathways in fibroblasts distinguished by pertussis toxin.

Abstract: The primary action of a family of mitogens including bombesin1,2, bradykinin3, vasopressin3,4 and α-thrombin5–7 is to activate the hydrolysis of polyphosphoinositides8. Hydrolysis of phosphatidyl-inositol 4,5-bisphosphate (PtdIns(4,5)P2) by phospholipase C is mediated through coupling of surface receptors to a GTP-binding protein9,10 (Gp protein) which, in some cells6,11,12, is inactivated by the toxin of Bordetella pertussis13. It is not known whether this signalling pathway is involved in initiating DNA replication, whereas it has been firmly established that reinitiation of DNA synthesis can be triggered without activation of PtdIns(4,5)P2 hydrolysis by, for example, EGF (epidermal growth factor) 14,15, FGF (fibroblast growth factor)16 and insulin/IGF-I (insulin-like growth factor-I)14, members of a class of mitogens known to activate receptor tyrosine kinases17,18. Taking advantage of the fact that Chinese hamster lung fibroblasts respond to either class of mitogens and that their Gp protein appears to be sensitive to pertussis toxin6, we have now analysed the toxin's effect on reinitiation of DNA synthesis and find that it inhibits up to 95% of thrombin-induced mitogenicity without affecting EGF- or FGF-induced DNA synthesis and proliferation. These findings strongly suggest that activation of PtdIns(4,5)P2-phospholipase C has a determinant function in growth control, and confirm the existence of alternative growth factor-signalling pathways independent of polyphosphoinositide breakdown.

The Astrophysical Gravitational Wave Stochastic Background

Abstract: A stochastic background of gravitational waves with astrophysical origins may have resulted from the superposition of a large number of unresolved sources since the beginning of stellar activity. Its detection would put very strong constraints on the physical properties of compact objects, the initial mass function and star formation history. On the other hand, it could be a 'noise' that would mask the stochastic background of its cosmological origin. We review the main astrophysical processes which are able to produce a stochastic background and discuss how they may differ from the primordial contribution in terms of statistical properties. Current detection methods are also presented.

The Introduced Green Alga Caulerpa Taxifolia Continues to Spread in the Mediterranean

Abstract: The tropical green alga Caulerpa taxifolia in the Mediterranean has spread steadily since its introduction in 1984. At the end of 2000, approximately 131 km2 of benthos had been colonized in 103 independent areas along 191 km of coastline in six countries (Spain, France, Monaco, Italy, Croatia and Tunisia). Large regions neighboring the invaded areas appear favorable to further colonization, and there is thus no reason to believe that spreading will slow down in the years to come.