The consumption of organic tomatoes (ORTs) reduces the risk of harmful effects to humans and the environment caused by exposure to toxic agrochemicals. In this study, we used the somatic mutation and recombination test (SMART) of wing spots in Drosophila melanogaster to evaluate the genotoxicity of ORT and the effect of cotreatment with ORT on the genotoxicity of Doxorubicin® (DXR, a cancer chemotherapeutic agent) that is mediated by free radical formation. Standard (ST) cross larvae were treated chronically with solutions containing 25%, 50% or 100% of an aqueous extract of ORT, in the absence and presence of DXR (0.125 mg/mL), and the number of mutant spots on the wings of emergent flies was counted. ORT alone was not genotoxic but enhanced the toxicity of DXR when administered concomitantly with DXR. The ORT-enhanced frequency of spots induced by DXR may have resulted from the interaction of ORT with the enzymatic systems that catalyze the metabolic detoxification of this drug.

ABSTRACT.Hypostomus is a group of fish with numerical and structural karyotypic variability. Among them, only six species, three of which belong to the Amazon basin, show a sex chromosome. In this study, we present the karyotype structure of Hypostomus cf. plecostomus from the Teles Pires river basin in the municipality of Alta Floresta, MT. The species has 2n = 68 and the karyotype formula 14m+ 24sm+ 14st+ 16a [fundamental number (FN) = 120] in males and 15m+ L.C. Oliveira et al. 6626©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (2): 6625-6634 (2015) 24sm+14st+15a (FN = 121) in females and sex chromosomes ZZ/ZW. Argyrophilic nucleolar organizer regions (AgNORs) were identified in two pairs of chromosomes at different positions: short arm of the pair 21and long arm of the pair 27, matching the signals displayed by 18S FISH and indicating multiple NORs. Analysis of band C detected few blocks of constitutive heterochromatin in the pericentromeric regions of most chromosomes and the telomeric regions of some pairs, including the nucleolar pair 21. However, large blocks on the long arm of the nucleolar pair 27 still stood out. GC-rich heterochromatin (CMA 3 ) was visualized only coincidently with nucleolar sites. Mapping of 5S rDNA sites with FISH revealed markings in eight chromosomes, demonstrating synteny between the 18S and 5S sites. The data obtained for H. cf. plecostomus are important for taxonomic studies of this Amazon complex "H. plecostomus group". The occurrence of sex chromosomes in Amazon species of Hypostomus suggests an evolutionary event that is independent of other species in the group.

beta-carotene (BC), pro-vitamin A, is an efficient antioxidant, effective in the neutralization of oxygen reactive species, which cause serious damage to DNA. Various studies have been conducted on the effectiveness of BC for chemoprevention of cancer and heart disease. Doxorubicin is a chemotherapeutic agent used for cancer treatment that generates free radicals. We examined the effects of BC (1, 2 and 4 mg/mL) on the genotoxicity of doxorubicin (0.125 mg/mL), using the wing spot test in Drosophila melanogaster (somatic mutation and recombination test). The BC alone had no significant effect on the frequency of mutant spots. However, it significantly reduced the number of spots caused by doxorubicin. We concluded that BC is not genotoxic and that it exerts protective effects against the genotoxic action of the chemotherapeutic free-radical generator doxorubicin.

ABStRACt. Caryocar brasiliense Camb. is a tree popularly known in Central Brazil as pequi. Its fruit contains carotenes, retinols, vitamin C, and polyphenols. These compounds possess antioxidant properties preventing excessive free radical formation and modulating the genotoxicity of physical and chemical agents in the body. However, at high concentrations these compounds can have recombinogenic and mutagenic effects, because they can act as prooxidants. We examined the genotoxic effects of aqueous extracts of pequi pulp on wing spots of Drosophila melanogaster using the somatic mutation and recombination test (SMART). SMART was applied to a standard cross and to a high bioactivation cross. Two types of descendants were obtained from these crosses: markedheterozygous (mwh + / + flr 3 ) and balancer-heterozygous (mwh + / + TM3, Bds). Seventy-two-hour larvae from both crosses were treated with pequi pulp extract at 1, 5 and 10%. The extract increased significantly the frequency of mutant spots when compared with the negative control. Recombinogenic effects were also observed in the mwh/TM3 descendants.

The rivers from the region of Catalão, Southeast Goiás State, Brazil, are exposed to intense anthropogenic influences including agricultural activities, industry, and urban waste. The aim of this study was to determine the severity of water pollution by conducting an experiment involving in situ biomonitoring of water constituents on genotoxicity in fish inhabiting these sites. The genotoxicity of three sites of the region were analyzed utilizing the micronucleus (MN) test. It was of interest to determine whether there were differences between sampling sites such as urban perimeter, agriculture, and fertilizer industry in control, and monitored species including Astyanax fasciatus, Astyanax altiparanae, and Characidium fasciatum. Data demonstrated that the species at sites 1, 2, and 3 exhibited a marked increase in frequency of MN compared to fish from site 4. Significant elevation in frequency of MN occurred in erythrocytes of A. fasciatus and A. altiparanae at sites 1 and 2. At site 3 higher frequencies of MN were observed in C. fasciatum. MN induction in C. fasciatum was correlated with chromium levels in water and sediment, while A. fasciatum and A. altiparanae showed an association with zinc in water and sediment. Data suggest that benthic and nektonic fish species display different sensitivities in relation to anthropogenic contaminant influences.