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Titolo:
BIOTRANSFORMATION OF GENOTOXIC AGENTS IN MARINE SPONGES - MECHANISMS AND MODULATION
Autore:
DEFLORA S; BAGNASCO M; BENNICELLI C; CAMOIRANO A; BOJNEMIRSKI A; KURELEC B;
Indirizzi:
UNIV GENOA,INST HYG & PREVENT MED,VIA PASTORE 1 I-16132 GENOA ITALY RUDJER BOSKOVIC INST,CTR MARINE RES ZAGREB 41001 CROATIA
Titolo Testata:
Mutagenesis
fascicolo: 4, volume: 10, anno: 1995,
pagine: 357 - 364
SICI:
0267-8357(1995)10:4<357:BOGAIM>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT-LIVER; SALMONELLA-TYPHIMURIUM; AROMATIC-AMINES; N-HYDROXYLATION; GLUTATHIONE; INDUCTION; FISH; METABOLISM; MUTAGENS; N-2-FLUORENYLACETAMIDE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
S. Deflora et al., "BIOTRANSFORMATION OF GENOTOXIC AGENTS IN MARINE SPONGES - MECHANISMS AND MODULATION", Mutagenesis, 10(4), 1995, pp. 357-364

Abstract

Marine sponges do not appear to suffer from neoplastic diseases, in spite of possible high exposures resulting from their nature as sessilebottom filter feeders which pump large volumes of sea water. The assessment of several parameters related to the biotransformation of mutagens/carcinogens showed that the metabolic machinery of sponge medulla cells is mainly oriented towards detoxification, with some differencesdepending on species (Geodia cydonium or Tethya aurantium). Glutathione (GSH) levels were unexpectedly high in these cells, especially in Geodia, in which the concentration of this tripeptide was more than twice that measured in liver preparations from untreated rats, at least when related to the protein content. The oxidoreductive enzyme activities involved in the glutathione cycle were balanced in such a way as tofavour a high GSH: oxidized glutathione (GSSG) ratio. GSH S-transferase activity was conversely rather low, compared to that of rat liver, and the dehydrogenases involved in the hexose monophosphate shunt werehigh in Tethya but low in Geodia. The metabolism of mutagens was investigated by using the Salmonella typhimurium his (-) strains TA100, TA98 and YG1024, Sponge S12 fractions failed to activate aflatoxin B1, benzo[a]pyrene and the two heterocyclic amines 3-amino-1-methyl-5H-pyrido[4,3-b]indole and 2-amino-3,4-dimethyl-imidazo[4,5-f]quinoline. Although far less efficiently than untreated rat liver S12 fractions. Geodia and especially Tethya preparations weakly activated the three aromatic amines 2-acetyl-aminofluorene, 2-aminofluorene and 2-aminoanthracene. On the other hand, sponge S12 fractions were remarkably efficient in decreasing the mutagenic potency of the direct-acting mutagens 4-nitroquinoline 1-oxide and sodium dichromate. The possibility of modulating biochemical parameters and metabolism of mutagens was explored by exposing sponge cubes to a variety of agents, either individually or in combination or sequentially. The most significant effects were a depletion of GSH produced by treatment with buthionine sulfoximine and, at least in part of the experiments, an increase of GSH stores producedby treatment with the thiol N-acetylcysteine. Irrespective of combination with other agents, exposure of sponges to 2-acetylaminofluorene resulted in an autoinduction of metabolic activation of the same compound and of its related compound 2-aminofluorene. Treatments with methimazole or verapamil had minor effects on the investigated parameters, However, in separate experiments verapamil, a calcium channel blocker inhibiting the P-glycoprotein pump, was found to enhance the accumulation of radioactive vincristine in Geodia and even more in Tethya, thus confirming the occurrence of a multixenobiotic resistance mechanism inmarine sponges.

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Documento generato il 30/09/20 alle ore 04:43:14