Infant rats can learn time intervals before the maturation of the striatum: evidence from odor fear conditioning.

Interval timing refers to the ability to perceive, estimate and discriminate durations in the range of seconds to minutes. Very little is currently known about the ontogeny of interval timing throughout development. On the other hand, even though the neural circuit sustaining interval timing is a matter of debate, the striatum has been suggested to be an important component of the system and its maturation occurs around the third post-natal (PN) week in rats.

Antimutagenic activity of anthocyanins isolated from Aronia melanocarpa fruits.

Anthocyanins belong to the flavonoid family and are ubiquitous in plants, especially in flower petals and fruit peels. We established that anthocyanins isolated from fruits of Aronia melanocarpa markedly inhibited the mutagenic activity of benzo(a)pyrene and 2-amino fluorene in the Ames test. In the Sister Chromatid Exchanges (SCEs) test with human blood-derived lymphocytes cultured in vitro, a significant decrease of SCEs frequency induced by benzo(a)pyrene was observed in the presence of anthocyanins.

Antimutagenic activity of fluphenazine in short-term tests.

Fluphenazine, an antipsychotic drug that belongs to the phenothiazine family, reduced the genotoxicity of direct- and indirect-acting mutagens in the Ames test, both in the presence and in the absence of promutagen-activating S9 fraction. In short-term tests on human lymphocytes, the inhibitory effect of fluphenazine on the genotoxicity of standard mutagens was strongest in the cytokinesis-blocked micronucleus assay and in the thioguanine resistance test, and weakest in the sister chromatid exchange test. Fluphenazine also considerably reduced the level of free radicals estimated in in vitro samples of human granulocytes.

Evaluation of genotoxic and immunotoxic activities of potential glucose biosensor components: ferrocenes.

Three ferrocenes used in glucose biosensor construction were tested in the aspect of genotoxic and immunotoxic activities. All three ferrocenes were not mutagenic in the standard bacterial Ames test. Equally in the Sister Chromatid Exchanges test in human lymphocyte cultures, the genotoxic action of tested ferrocenes could be excluded.

Inhibition of potassium dichromate mutagenicity by todralazine.

Todralazine, an antihypertensive drug of the hydrazinoph-thalazine group, markedly decreased the mutagenic activity of potassium dichromate in standard bacterial tests. At the highest todralazine dose tested inhibition of potassium dichromate mutagenic activity by approximately 90% in the Ames test and up to 100% (complete) inhibition in the Bacillus subtilis rec- assay was observed. Spectrophotometric analyses proved that todralazine induced reduction of Cr(VI) to Cr(III) and complexation of Cr(III) ions.

Antimutagenic activity of alkylresorcinols from cereal grains.

Alkylresorcinols, natural amphiphilic compounds commonly found in cereal grains, markedly decreased mutagenic activity of four standard mutagens examined in the Ames test. The effect was the strongest in the case of indirect-acting mutagens, benzo[a]pyrene and 2-aminofluorene. In the case of direct-acting mutagens, daunorubicin and methyl methanesulfonate, the diminution of the mutagenic activity by the alkylresorcinols was smaller but still noticeable.

Evaluation of the mechanisms of todralazine effect on mutagenicity of benzo(a)pyrene.

We have previously described that todralazine markedly decreased mutagenicity of several indirect- and direct-acting mutagens. In this paper we report the results of experiments conducted in order to evaluate the involvement of desmutagenic and bio-antimutagenic activities in the observed antimutagenic effect of todralazine. The results of the Ames test suggest a bio-antimutagenic, and not desmutagenic effect of todralazine.

Todralazine influence upon the mutagenicity of some direct- and indirect-acting mutagens.

Todralazine decreased the mutagenic activity of tested direct- and indirect-acting mutagens. Despite the marked differences between efficient todralazine doses (ED50) it was observed that, in the case of tested indirect mutagens as well as in some of the direct mutagens, the decrease of mutagenicity by todralazine was very strong, exceeding 80% in some cases.

In vitro studies on the DNA impairments induced by Cr(III) complexes with cellular reductants.

The influence of Cr(III) complexes with ascorbic acid, cysteine and glutathione on DNA has been studied spectrophotometrically and chromatographically. The toxic and genotoxic activities of these complexes were also investigated. It was found that these complexes bind to DNA weaker than hexaaqua Cr(III) complexes.

Study of the mechanism of todralazine antimutagenic activity: the effect upon mutagenicity of daunorubicine.

Todralazine markedly reduced the mutagenic activity of the standard direct-acting mutagen--daunorobicine (DRC)--in the Ames test. Spectrophotometric measurements proved that todralazine did not interact with DRC in water solution. Todralazine neither interacted with calf thymus DNS in vitro, nor changed the interaction of DRC with DNA.

Mutagenic activity of drinking water in Wroclaw, Poland.

The Salmonella mutagenicity test was applied to the evaluation of mutagenic activity of Wroclaw drinking water. Contaminants of water samples were concentrated by adsorption on XAD-2 resin. After while they were eluted sequentially with acetone, dichloromethane/methanol (1:1, v/v) and methanol, and then obtained organic extracts were evaporated to dryness.

Mutagenicity of B(a)P in the presence of some hydralazine derivatives.

Hydralazine, dihydralazine and todralazine were tested in the aspect of their mutagenic potency, and the influence upon the mutagenicity of standard promutagen--B(a)P. Hydralazine exhibited strong mutagenic activity in the Ames test while mutagenic activity of dihydralazine was relatively weak. Todralazine had no mutagenic activity, and significantly decreased mutagenicity of B(a)P.

Mutagenic activity of copper(II) chromate and dichromate complexes with polypyridines.

Copper(II) chromate and dichromate complexes with 2,2'-bipyridyl and 1,10-phenathroline were tested for their mutagenic activity in the standard Ames test. All of six tested complexes exhibited markedly lower mutagenic activity than the reference compounds--potassium dichromate and sodium chromate. The blockage of Cr(VI) reduction capability in the presence of the complex Cu2+ ion and the competition between copper and chromium ions in the interaction with cellular components are discussed in the light of the results of our previous chemical study.

Chrysotile A affects YAC-1 cytolytic activity of spleen cells.

Effect of short exposure of C57Bl/6 and F1/NZB x C57Bl/6/ mice to i.p. injected chrysotile A on YAC-1 cytolytic potential (NK cell function) of spleen cells was investigated.

Genotoxicity of air pollution in a non-ferrous metal foundry in three bacterial tests and a micronucleus test--a comparative study.

Acetone extracts of dusts and fumes collected at workplaces in a non-ferrous metal foundry exhibited genotoxic activity in all of the tests used. Of the compared tests, the Ames method is the most useful for preliminary screening detection of the genotoxic agents that are present in acetone extracts of dusts and fumes emitted at workplaces in a non-ferrous metal foundry.

Presentation of benzo(a)pyrene to microsomal enzymes by asbestos fibers in the Salmonella/mammalian microsome mutagenicity test.

The potential effect of asbestos fibers on mutagenicity of benzo(a)pyrene was investigated by using the Ames test. Asbestos fibers without a coating of benzo(a)pyrene or benzo(a)pyrene when not dissolved in DMSO lacked any mutagenic effect in the Salmonella/mammalian microsome mutagenicity test. However, when benzo(a)pyrene was adsorbed onto asbestos, significant numbers of mutated bacteria were observed.

Polynucleotide sequence divergence among some coagulase-negative staphylococci.

The degree of binding was determined, at both exacting and non-exacting temperatures, between deoxyribonucleic acid (DNA) preparations from coagulase-negative staphylococci and carbon (14C) labelled DNA from nine reference strains, Staphylococcus capitis LK499, S. cohnii GH137, S. epidermidis GH37, S.

DNA homology studies on Nocardia and Rhodococcus strains.

The genetic homogeneity of Nocardia amarae, Nocardia autotrophica and Rhodococcus strains and the relationship among these groups of microorganisms have been studied using the DNA reassociation method. Strains belonging to N. amarae and N.

Deoxyribonucleic acid reassociation in the classification of the 'rhodochrous' complex and allied taxa.

The degree of binding was determined between DNA preparations from gordonae and rhodochrous strains and uracil-labelled DNA from five reference strains, Nocardia asteroides NK20, N. pellegrino PII, Gordona bronchialis TI, G. terrae T5 and rhodochrous strain R90.