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Biomedical subjects

R Marcos

Publications and source records attributed to R Marcos.

At least 127 records · Page 7Linked to original sources
PubMed1987

Studies on the toxicity of cypermethrin and fenvalerate in different strains of Drosophila melanogaster Meig. (Insecta, Diptera).

To improve our knowledge of pyrethroid toxicity mechanisms, Drosophila melanogaster was chosen as a model species, with well-defined characteristics. This study reports the results of the toxic effects of cypermethrin and fenvalerate on larvae and adults of four D. melanogaster strains. Our results show that cypermethrin is more toxic than fenvalerate at larval and adult stages, that growth on media containing insecticide significantly decreases the rate of preimaginal development, and that adult males are more sensitive than are females to both insecticides.

Animals↗
PubMed1987

Non-mutagenicity of fenvalerate in Drosophila.

The induction of genetic damage in germ cells of Drosophila melanogaster by the pyrethroid insecticide fenvalerate was studied. Adult feeding, larval feeding and adult injection were the routes of administration used. Our results indicate that, under the conditions of testing, fenvalerate is unable to induce sex-linked recessive lethals, sex-chromosome losses and non-disjunction.

Animals↗
PubMed1987

Mutagenicity studies on fenitrothion in Drosophila.

To extend the data on the possible genotoxic effects of organophosphorus pesticides, the insecticide fenitrothion was tested for the induction of gene and chromosome mutations in male germ cells of Drosophila melanogaster. Sex-linked recessive lethals, total and partial sex-chromosome losses and non-disjunction were studied following different exposure methods: adult feeding, injection and larval feeding. In the tests assaying for recessive lethals, we used a MRA strain resistant to malathion. Our results indicate that fenitrothion, at concentrations ranging from 50 to 150 p.p.m., is unable to induce any kind of genetic damage in D. melanogaster, at least under the conditions of testing.

Animals↗
PubMed1986

Indication for weak mutagenicity of the organophosphorus insecticide dimethoate in Drosophila melanogaster.

The organophosphorus insecticide dimethoate was tested for induction of genetic damage in male germ cells of Drosophila melanogaster. Sex-linked recessive lethals, sex-chromosome loss and non-disjunction induction were studied following different routes of administration: adult feeding, injection and larval feeding. Our results show that, after injection, dimethoate induces a slight but significant increase in the frequency of point mutations.

Animals↗
PubMed1986

Mutagenicity testing of the pyrethroid insecticide cypermethrin in Drosophila.

The pyrethroid insecticide cypermethrin was tested for the induction of genetic damage in male germ cells of Drosophila melanogaster. Sex-linked recessive lethals, sex-chromosome loss and non-disjunction were studied following different routes of administration: adult feeding, injection and larval feeding. Our results show that, after adult injection and larval ingestion, cypermethrin induces a small but significant increase in the frequency of sex-linked recessive lethal mutations. However, no significant increases were observed in the frequency of sex chromosome loss or non-disjunction after exposure of male flies to cypermethrin at concentrations up to 20 p.p.m.

Animals↗
PubMed1985

Evaluation of genetic damage induced by 8-ethoxycaffeine in Drosophila melanogaster.

The methylated oxypurine, 8-ethoxycaffeine (EOC), was tested for the induction of genetic damage in Drosophila melanogaster. Sex-linked recessive lethals, sex-chromosome loss and tanslocation induction were studied following treatment of adult males, using a feeding technique. Our results show that EOC induces sex-chromosome loss and translocations between the second and third chromosomes, but is unable to induce point mutations in male germ cells under our conditions of testing.

Animals↗
PubMed1985

Testing of chloroquine and quinacrine for mutagenicity in Drosophila melanogaster.

To extend the data on the mutagenic effects of intercalating agents in Drosophila melanogaster, chloroquine and quinacrine were tested for the induction of genetic damage in D. melanogaster males. Sex-linked recessive lethals and sex-chromosome loss induction were studied following treatment of adult males using a feeding technique. Our results show that both intercalating compounds increase significantly the frequency of sex-linked recessive lethals, but are unable to induce sex-chromosome loss in male germ cells under the conditions of testing.

Animals↗
PubMed1984

Induction of male recombination in Drosophila melanogaster by chemical treatment.

Acridine orange (AO), ethidium bromide (EB), ethyl methanesulfonate (EMS) and 8- ethoxycaffeine ( EOC ) were fed to larvae of Drosophila melanogaster in order to test their capacity for the induction of meiotic recombination in males. Our results show that AO and EB increase significantly the male recombination frequencies. No relationship between chromosome breakage ability and male recombination induction was found since EMS and EOC , two effective chromosome-breaking agents, were unable to increase the male recombination.

Acridine Orange↗
PubMed1983

Differences between drosophila melanogaster and its sibling species D. simulans in sensitivity to acridine orange treatment.

Larvae and adults of D. melanogaster and D. simulans were fed with acridine orange, in order to test sensitivity differences between the species. Our results show that, of the two species, D. simulans is more resistant in the larval stages, and D. melanogaster is more resistant in the adult stage. Furthermore, adult males of both species are more sensitive than adult females.

Acridine Orange↗
PubMed1983

Sensitivity of different strains of Drosophila melanogaster to endosulfan and malathion.

Four Drosophila melanogaster populations, two of them (ER1 and ER2) previously selected for adult resistance to endosulfan, were examined for response to endosulfan and malathion treatment. Both insecticides were fed to larvae and adult males and females to test their toxic capacity. Our results show that malathion is more toxic than endosulfan, that adult males are more sensitive to both insecticides than females, and that resistance of ER1 and ER2 strains is restricted to the insecticide to which they had been exposed previously (endosulfan).

Animals↗
PubMed1982

Effect of cycloheximide on different stages of Drosophila melanogaster.

Cycloheximide, an antibiotic inhibiting protein synthesis, exerted a toxic effect on different developmental stages egg, larva and adult of Drosophila melanogaster. At the egg stage the early embryos were most sensitive. With larvae, a strong decrease in viability was found, with no sex difference. In adults, there was a dose-effect relationship, mortality increasing with concentration. At 10 and 15 mM, males were more sensitive than females. There were consistent differences between the control and cycloheximide-fed females in respect of the average number of eggs deposited and offspring produced.

Animals↗
PubMed1982

[Use of Drosophila in the detection of potentially carcinogenic agents].

The authors make a brief review of the value of using the fly Drosophila melanogaster to detect possible mutagenic and carcinogenic activities of chemicals. The study of the induction of chromosome X-linked recessive lethal mutations, translocations and chromosomal deletions, and non-disjunction phenomena in Drosophila is very useful to detect direct carcinogenic agents a well as precarcinogenic compounds that are ativated within the fly organism. The assays with Drosophila do not substitute, but follow and complement at a different biological level the assays made in batteries of tests employing bacteria.

Animals↗
PubMedDate not supplied

Induction of mutations by tritiated water and 3H-thymidine in Drosophila melanogaster assayed by the somatic zeste-white eye mutation system.

In order to study the mutagenic effect of exposure to tritium, Drosophila melanogaster larvae were treated with tritiated water (3H2O) or tritiated thymidine (3H-TdR) during development. Dose rates ranged from 0.0058 to 0.058 rad/h per nucleus for 3H-TdR and from 0.049 to 0.122 rad/h for 3H2O. Induction of mutations was measured by the appearance of somatic mutations in the eyes of an unstable strain of Drosophila melanogaster. Both substances caused a significant increase in mutation frequency. With the assumption that each mutation observed in this assay is caused by one DNA break, the effectiveness of tritium to create DNA breaks is estimated to be 0.20 breaks per decay for 3H-TdR and 0.27 breaks per decay for 3H2O.

Animals↗