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| Chini,E.N.. |
| Cells possess multiple intracellular Ca2+-releasing systems. Sea urchin egg homogenates are a well-established model to study intracellular Ca2+ release. In the present study the mechanism of interaction between three intracellular Ca2+ pools, namely the nicotinic acid adenine dinucleotide phosphate (NAADP), the cyclic ADP-ribose (cADPR) and the inositol 1',4',5'-trisphosphate (IP3)-regulated Ca2+ stores, is explored. The data indicate that the NAADP Ca2+ pool could be used to sensitize the cADPR system. In contrast, the IP3 pool was not affected by the Ca2+ released by NAADP. The mechanism of potentiation of the cADPR-induced Ca2+ release, promoted by Ca2+ released from the NAADP pool, is mediated by the mechanism of Ca2+-induced Ca2+ release. These data... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: CADPR; NAADP; Calcium; Sea urchin eggs; Fertilization; IP3. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000500005 |
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| Costa-Lotufo,L.V.; Ferreira,M.A.D.; Lemos,T.L.G.; Pessoa,O.D.L.; Viana,G.S.B.; Cunha,G.M.A.. |
| Auxemma oncocalyx Taub. belongs to the Boraginaceae family and is native to the Brazilian northeast where it is known as "pau-branco". We investigated the ability of the water soluble fraction isolated from the heartwood of A. oncocalyx to inhibit sea urchin egg development. This fraction contains about 80% oncocalyxone A (quinone fraction), a compound known to possess strong cytotoxic and antitumor activities. In fact, the quinone fraction inhibited cleavage in a dose-dependent manner [IC50 of 18.4 (12.4-27.2) µg/ml, N = 6], and destroyed the embryos in the blastula stage [IC50 of 16.2 (13.7-19.2) µg/ml, N = 6]. We suggest that this activity is due to the presence of oncocalyxone A. In fact, these quinones present in A. oncocalyx extract have strong... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Auxemma oncocalyx; Quinones; Sea urchin eggs; Oncocalyxone A. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000800010 |
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