Search results for "Mutagens"

Inhibition of clastogenicity of benzo[a]pyrene and of its trans-7,8-dihydrodiol in mice in vivo by fruits, vegetables, and flavonoids.

2003

In the in vivo mouse bone marrow micronucleus assay, homogenates of spinach, artichoke, peaches, and blue grapes as well as commercial concentrates of these vegetables and fruits reduced induction of micronuclei by benzo[a]pyrene (BaP) by 43-50%. Concentrates of strawberries (31% reduction) and of cauliflower (20% reduction) were less potent. Inhibition of genotoxicity by spinach and peaches was not caused by any delay in maturation of micronucleated erythrocytes as shown by experiments with sampling times of 24, 48, and 72 h after dosing of BaP. Pre-treatment of the mice with spinach 48, 24, and 12h before application of BaP resulted in a 44% reduction of micronuclei while peaches generate…

Studies on the induction of gene mutations in bacterial and mammalian cells by the ring-opened benzene metabolites trans,trans-muconaldehyde and tran…

1990

t,t-Muconaldehyde and t,t-muconic acid have been investigated for the induction of gene mutations in Salmonella typhimurium (reversion of the his- strains TA97, TA98, TA100, TA102, TA104 and TA1535), Escherichia coli (reversion of the trp- strain WP2 uvrA) and Chinese hamster V79 cells (acquisition of resistance toward 6-thioguanine). t,t-Muconaldehyde proved weakly mutagenic in strain TA104 in the presence and absence of NADPH-fortified postmitochondrial fraction from rat liver homogenate (S9 mix). In strains TA97, TA100 and TA102, weak positive responses were observed only in the presence of S9 mix. In strains TA98, TA1535 and WP2 uvrA, the result was negative. In V79 cells, the mutation …

Differential modulation of CYP2E1 activity by cAMP-dependent protein kinase upon Ser129 replacement.

1998

Many toxic compounds are activated by cytochrome P450 (CYP) 2E1 to reactive metabolites, which represents a potential hazard for cellular homeostasis. Therefore knowledge about CYP2E1 regulation could be of great biological importance. It has been shown that CYP2E1 is controlled transcriptionally and post-translationally by phosphorylation. In the present study we investigated the role of serine-129 (Ser129) in the protein kinase A (PKA) recognition sequence motif Arg-Arg-Phe-Ser129. To gain further insights into the possible relevance of Ser129 for CYP2E1 function, Ser129 was replaced by alanine (Ala) or glycine (Gly) by site-directed mutations of the cDNA coding for CYP2E1. The mutant cDN…

Liver subcellular fractions from rats treated by organosulfur compounds from Allium modulate mutagen activation

2000

The effects of in vivo administration of naturally occurring organosulfur compounds (OSCs) from Allium species were studied on the activation of several mutagens. Male SPF Wistar rats were given p.o. one of either diallyl sulfide (DAS), diallyl disulfide (DADS), dipropyl sulfide (DPS) or dipropyl disulfide (DPDS) during 4 consecutive days and the ability of hepatic S9 and microsomes from treated rats to activate benzo[a]pyrene (BaP), cyclophosphamide (CP), dimethylnitrosamine (DMN), N-nitrosopiperidine (N-PiP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was determined in the Ames test. Administration of DAS, DPS and DPDS resulted in a significant increase of the activation of…

Genotoxic potential of by-products in drinking water in relation to water disinfection: Survey of pre-ozonated and post-chlorinated drinking water by…

2006

Mutagenic potential of drinking water samples derived from ranneywells was studied. 100-100 l of untreated (rough) and ozone-treated as well as chlorinated-disinfected water were dropped on and adsorbed by macroreticular resin columns (Serdolit PAD-III and Amberlite XAD-2). The adsorbed material was desorbed by methanol and dichloromethane. After elimination of the solvents by vacuum distillation the adsorbed material was dissolved in dimethylsulfoxide. The mutagenic activity was tested in the Ames-Salmonella/rat liver microsome system. The tester strains were TA-98 and TA-100. The material adsorbed to Serdolit PAD-III from rough and also disinfected water did not induce mutagenicity in cas…

In vivo antigenotoxic effects of dietary allyl sulfides in the rat

1997

The effects of dietary administration of diallyl sulfide (DAS), diallyl disulfide (DADS) and allyl mercaptan (AM) on the genotoxicity of different chemicals were studied in two experimental systems: (i) measurement of hepatic DNA single-strand breaks induced in rats by aflatoxin B1 (AFB1), N-nitrosodimethylamine (NDMA) or methylnitrosourea (MNU); (ii) mutagenicity of AFB1 or NDMA on Salmonella typhimurium TA100 using hepatic S9 from rats fed allyl sulfides as the activation system. All compounds strongly reduced hepatic DNA breaks induced by AFB1 and NDMA but did not modify the genotoxicity of MNU. In the Ames test, the mutagenicity of NDMA was strongly inhibited by hepatic S9 from rats fed…

Metabolic activation to a mutagen of 3-hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, a secondary metabolite of benzo[a]pyrene

1987

3-Hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (3-OH-BP-7,8-diol) was isolated from arylsulfatase/beta-glucuronidase-treated bile of rats to which 3-hydroxybenzo[a]pyrene (3-OH-BP) has been administered. This triol was investigated for mutagenicity in Salmonella typhimurium (reversion to histidine prototrophy of strains TA 97, TA 98, TA 100 and TA 1537) and in V79 Chinese hamster cells (acquisition of resistance to 6-thioguanine). When no exogenous metabolizing system was added the triol was inactive, while 3-OH-BP showed weak mutagenic effects with all four bacterial strains. In the presence of NADPH-fortified postmitochondrial supernatant fraction (S9 mix) of liver homogenate fro…

Clavine alkaloids and derivatives as mutagens detected in the Ames test.

1992

Eight cytostatic clavines were investigated for mutagenicity in Salmonella typhimurium (reversion of the his-strains TA98, TA100, TA102 and TA1537), directly and in the presence of a mammalian xenobiotic metabolizing system, S9 (NADPH-fortified postmitochondrial fraction of liver homogenate from Aroclor 1254-treated rats). Four compounds (festuclavine, 17-bromofestuclavine, 1-allylelymoclavine and 1-methyllysergol methyl ether) were direct mutagens, whose activity was enhanced in the presence of S9. The other compounds (1-cyclopentylfestuclavine, 13-bromo-1-cyclopropylmethylfestuclavine, 6-cyano-1-propyl-6-norfestuclavine and 6-allyl-1-propyl-6-norfestuclavine) showed mutagenic effects only…

The mutagenicity of MCPA and its soil metabolites, chlorinated phenols, catechols and some widely used slimicides in Finland

1977

Modulation of the control of mutagenic metabolites derived from cyclophosphamide and ifosfamide by stimulation of protein kinase A

1990

The phosphorylation of the 2 major phenobarbital-inducible cytochrome P450 isoenzymes IIB1 and IIB2 was increased in intact hepatocytes by the action of the membrane-permeating cAMP derivative N6,O2'-dibutyryl-cAMP. Under these conditions cyclophosphamide and ifosfamide (which are known to be activated by cytochrome P450 IIB1) were investigated for mutagenicity in Salmonella typhimurium TA1535 and TA100 and for cytotoxicity in TA1535. Cyclophosphamide and ifosfamide were transformed to mutagenic and cytotoxic metabolites by the hepatocytes. The activation of both drugs to mutagens was markedly reduced after pretreatment of the hepatocytes with the membrane-permeating cAMP derivative N6,O2'-…