Identification of Novel Induced Mutations in Seed and Vegetatively Propagated Plants from Reduced Representation or Whole Genome Sequencing Data.

Treatment of plants with chemical mutagens results primarily in the production of novel single nucleotide variants. Mutagenesis is a mostly random process and as such plants derived from mutagenesis of different seeds or in vitro material are expected to accumulate different mutations. An important step in the creation of a mutant population for forward or reverse genetics is the choice of treatment conditions (e.g., dosage) such that sufficient mutations accumulate while not adversely affecting propagation of the plant. DNA sequencing provides a quick method to evaluate the effect of different treatment conditions and their effect on the density and spectrum of accumulated mutations. Whole genome sequencing or reduced representation sequencing is carried out followed by mapping to a reference genome and production of a Variant Call Format (VCF) file. We provide here a method for generating a multi-sample VCF from mutagenized plants and describe a new tool to streamline the process of recovering unique induced mutations and determining their possible effect on gene function.

Newly discovered clouting interplay between matrix metalloproteinases structures and novel quaternary Ammonium K21: computational and in-vivo testing.

AIMS AND OBJECTIVES: To analyze anti-MMP mode of action of Quaternary Ammonium Silane (QAS, codenamed as k21) by binding onto specific MMP site using computational molecular simulation and Anti-Sortase A (SrtA) mode of action by binding onto specific site using computational molecular simulation. MATERIALS AND METHODS: In silico Molecular Dynamics (MD) was used to determine the interactions of K21 inside the pocket of the targeted protein (crystal structure of fibroblast collagenase-1 complexed to a diphenyl-ether sulphone based hydroxamic acid; PDB ID: 966C; Crystal structure of MMP-2 active site mutant in complex with APP-derived decapeptide inhibitor. MD simulations were accomplished with the Desmond package in Schrödinger Drug Discovery Suite. Blood samples (~ 0.5 mL) collected into K2EDTA were immediately transferred for further processing using the Litron MicroFlow® PLUS micronucleus analysis kit for mouse blood according to the manufacturer's instructions. Bacterial Reverse Mutation Test of K21 Molecule was performed to evaluate K21 and any possible metabolites for their potential to induce point mutations in amino acid-requiring strains of Escherichia coli (E. coli) (WP2 uvrA (tryptophan-deficient)). RESULTS: Molecular Simulation depicted that K21 has a specific pocket binding on various MMPs and SrtA surfaces producing a classical clouting effect. K21 did not induce micronuclei, which are the result of chromosomal damage or damage to the mitotic apparatus, in the peripheral blood reticulocytes of male and female CD-1 mice when administered by oral gavage up to the maximum recommended dose of 2000 mg/kg. The test item, K21, was not mutagenic to Salmonella typhimurium (S. typhimurium) strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2 uvrA in the absence and presence of metabolic activation when tested up to the limit of cytotoxicity or solubility under the conditions of the test. CONCLUSION: K21 could serve as a potent protease inhibitor maintaining the physical and biochemical properties of dental structures.

Deciphering induced variability, character association and multivariate analysis utilizing gamma rays and ethyl methanesulfonate in bread wheat (Triticum aestivum L.) genotypes with differential grain texture.

PURPOSE: Sustainable wheat production and higher genetic gains can be realized by broadening the genetic base and improving the well adapted varieties. In the present study, a multi-year experiment involving induced mutagenesis was conducted to create genetic variation, assess trait associations and genetic divergence in four wheat varieties with differential grain texture treated with six doses of gamma rays and ethyl methane sulfonate using ten agro-morphological traits. MATERIALS AND METHODS: Healthy selfed seeds of four bread wheat varieties with differential texture were irradiated using six doses ranging from 175 Gy-300 Gy of gamma rays (Co60: BARC, Mumbai) and six concentrations of ethyl methanesulfonate (0.3-1.3%) (Sigma-Aldrich, Bangalore, India) to evaluate variability, character association and degree of genetic diversity induced among the mutagenic treatments of wheat varieties with differential grain texture. RESULTS: Significant inter-population differences were observed for almost all the traits. The sample mean of twelve mutant populations in each of the cultivar exhibited superior quantitative phenotypic traits and increased values of the genetic parameters. Based on association and variability studies, plant height, spike length, grain filling period, biological yield per plant and harvest index can be used as early generation criteria for maximum genetic improvement. Multivariate studies indicated the contribution of various traits towards divergence and indicated the efficiency of mutagens in generating variability. Gamma-irradiation dosages between 200-250 Gy and 0.5-1.1% EMS for soft-textured varieties, whereas doses between 225-275 Gy and 0.5-0.9% EMS were found to be most potent for semi-hard-textured varieties. CONCLUSIONS: Assessment of mutagen sensitivity showed that semi-hard wheat varieties were responsive to both mutagens, particularly EMS and generated higher variability and divergence than the soft textured varieties. Hence, gamma rays were proved to be more effective in generating higher variability than ethyl methanesulfonate. A total of 117 putative mutants were identified with desirable agro-morphological attributes. Among these, mutants with higher inter-cluster distance can be used as parents in hybridization programs and serve as important genetic resources in future wheat improvement programs.

Cellular toxicity and DNA damage induced by Newbouldia laevis used for male infertility treatment in prokaryotic and eukaryotic models.

Leaves of Newbouldia laevis have been extensively used in solving problems associated with infertility and childbirth in many African countries. Yet, information is very limited on the DNA damaging potential of this plant. This study evaluated the cytogenotoxic effect of the aqueous extract of N. laevis leaf using prokaryotic models (Ames Salmonella fluctuation test using TA100 and TA98 strains of Salmonella typhimurium and SOS Chromotest with Escherichia coli PQ37) and eukaryotic model (Allium cepa root cells). Identification of the volatile organic compounds (VOCs) and phytochemical screening of the plant extract were also performed. Onion bulbs were grown on each concentration (1 to 50%; v/v, extract/tap water) of the extract for chromosomal aberrations and root growth analyses. Results of the Ames test indicated that the extract is mutagenic while the SOS Chromotest results showed good complementation to the Ames test results, although the E. coli PQ37 system showed slightly higher sensitivity in the detection of mutagenicity and genotoxicity of the extract. The plant extract was cytotoxic when compared to the control, inducing a significant (p < 0.05) concentration-dependent inhibition of root growth from 5 to 50% concentrations. At 50% concentration, the extract completely inhibited cell division in the A. cepa. Also, chromosomal aberration increased significantly (p < 0.05) in exposed onions from 5 to 20% concentrations. The mutagenicity and cytogenotoxicity recorded in this report were believed to be caused by the presence of VOCs such as 1,2,3-benzene-triol, 1,2-benzenediol, and 5-hydroxymethylfurfural, and alkaloids in the extract an indication of the cytogenotoxicity of the aqueous extract of N. laevis leaf even at low concentration.

Mutagenic sensitivity, effectiveness and efficiency of gamma rays and ethyl methane sulfonate on soft and semi-hard bread wheat (Triticum aestivum L.) varieties in the north-western Himalayan climate.

PURPOSE: The North-western Himalayan region requires unique varietal traits for the cultivation and quality of grain produced. Wheat varieties released for this zone in the past remained very popular among the farmers. However, with the passage of time certain traits such as the appearance of pathogenic rust races and grain softness have become threat to the fecundity of these genotypes and needs immediate improvement in this region. Mutation breeding facilitates improving one or two traits of a popular cultivar and to generate variability for most of plant traits upon which selection can be imposed. The purpose of this study is to evaluate the mutagenic sensitivity, effectiveness and efficiency of physical and chemical mutagens in four bread wheat varieties with differential grain texture. MATERIALS AND METHODS: Four bread wheat varieties; HS 490, HPW 89, HPW 360 and HPW 251 were irradiated using six doses of gamma rays (γ-rays) ranging from 175 to 300 Gy; Co60 source (BARC, Mumbai, India) and six doses of ethyl methane sulfonate (EMS) ranging from 0.3 to 1.3%; EMS (Sigma-Aldrich, Bangalore, India) to assess their mutation sensitivity, effectiveness, efficiency and spectrum of induced macro-mutations in M1 and M2 generation. RESULTS: Based on mutagen sensitivity tests, both gamma rays and ethyl methane sulfonate had similar effects as the doses/concentrations increased in all four varieties. Ethyl methane sulfonate had a discernible effect on seed germination and growth parameters as compared to gamma irradiated treatments. Pollens viability studies confirmed the differential effects of both mutagens on germination and plant survivability. The LD50 and LC50 values varied between 290-315 Gy for gamma rays and 0.90-1.35% for EMS under controlled laboratory conditions, however, the range substantially differs for gamma rays (240-290 Gy) and for EMS (0.50-1.1%) under field conditions, irrespective of the variety treated. The frequency of chlorophyll mutations was low and showed a linear correlation with the doses/concentrations of the mutagen. A total of 117 putative mutants with desirable agro-morphological characteristics were also isolated. Mutagenic effectiveness and efficiency results showed that gamma irradiation doses of 250-300 Gy and ethyl methane sulfonate of 0.7-1.3% were most potent for an effective mutation breeding programme in wheat crop. CONCLUSIONS: It was found that semi-hard textured varieties showed higher sensitivity to chemical mutagens as compared to soft-textured varieties. Gamma irradiation dose of 250-300 Gy and ethyl methane sulfonate concentration of 0.7-1.3% were found to be most effective and efficient across four bread wheat varieties and can be used in large scale mutagenesis programmes.

Uridine-cytidine kinase 2 potentiates the mutagenic influence of the antiviral ß-d-N4-hydroxycytidine.

Molnupiravir (EIDD-2801) is an antiviral that received approval for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection. Treatment of bacteria or cell lines with the active form of molnupiravir, ß-d-N4-hydroxycytidine (NHC, or EIDD-1931), induces mutations in DNA. Yet these results contrast in vivo genotoxicity studies conducted during registration of the drug. Using a CRISPR screen, we found that inactivating the pyrimidine salvage pathway component uridine-cytidine kinase 2 (Uck2) renders cells more tolerant of NHC. Short-term exposure to NHC increased the mutation rate in a mouse myeloid cell line, with most mutations being T:A to C:G transitions. Inactivating Uck2 impaired the mutagenic activity of NHC, whereas over-expression of Uck2 enhanced mutagenesis. UCK2 is upregulated in many cancers and cell lines. Our results suggest differences in ribonucleoside metabolism contribute to the variable mutagenicity of NHC observed in cancer cell lines and primary tissues.

Mutagenic effects of a commercial glyphosate-based herbicide formulation on the soil filamentous fungus Aspergillus nidulans depending on the mode of exposure.

Glyphosate-based herbicides (GBH) are the most used pesticides worldwide. This widespread dissemination raises the question of non-target effects on a wide range of organisms, including soil micro-organisms. Despite a large body of scientific studies reporting the harmful effects of GBHs, the health and environmental safety of glyphosate and its commercial formulations remains controversial. In particular, contradictory results have been obtained on the possible genotoxicity of these herbicides depending on the organisms or biological systems tested, the modes and durations of exposure and the sensitivity of the detection technique used. We previously showed that the well-characterized soil filamentous fungus Aspergillus nidulans was highly affected by a commercial GBH formulation containing 450 g/L of glyphosate (R450), even when used at doses far below the agricultural application rate. In the present study, we analysed the possible mutagenicity of R450 in A. nidulans by screening for specific mutants after different modes of exposure to the herbicide. R450 was found to exert a mutagenic effect only after repeated exposure during growth on agar-medium, and depending on the metabolic status of the tested strain. The nature of some mutants and their ability to tolerate the herbicide better than did the wild-type strain suggested that their emergence may reflect an adaptive response of the fungus to offset the herbicide effects. The use of a non-selective molecular approach, the quantitative random amplified polymorphic DNA (RAPD-qPCR), showed that R450 could also exert a mutagenic effect after a one-shot overnight exposure during growth in liquid culture. However, this effect was subtle and no longer detectable when the fungus had previously been repeatedly exposed to the herbicide on a solid medium. This indicated an elevation of the sensitivity threshold of A. nidulans to the R450 mutagenicity, and thus confirmed the adaptive capacity of the fungus to the herbicide.

Anti-Trypanosoma cruzi Activity, Mutagenicity, Hepatocytotoxicity and Nitroreductase Enzyme Evaluation of 3-Nitrotriazole, 2-Nitroimidazole and Triazole Derivatives.

Chagas disease (CD), which is caused by Trypanosoma cruzi and was discovered more than 100 years ago, remains the leading cause of death from parasitic diseases in the Americas. As a curative treatment is only available for the acute phase of CD, the search for new therapeutic options is urgent. In this study, nitroazole and azole compounds were synthesized and underwent molecular modeling, anti-T. cruzi evaluations and nitroreductase enzymatic assays. The compounds were designed as possible inhibitors of ergosterol biosynthesis and/or as substrates of nitroreductase enzymes. The in vitro evaluation against T. cruzi clearly showed that nitrotriazole compounds are significantly more potent than nitroimidazoles and triazoles. When their carbonyls were reduced to hydroxyl groups, the compounds showed a significant increase in activity. In addition, these substances showed potential for action via nitroreductase activation, as the substances were metabolized at higher rates than benznidazole (BZN), a reference drug against CD. Among the compounds, 1-(2,4-difluorophenyl)-2-(3-nitro-1H-1,2,4-triazol-1-yl)ethanol (8) is the most potent and selective of the series, with an IC50 of 0.39 µM and selectivity index of 3077; compared to BZN, 8 is 4-fold more potent and 2-fold more selective. Moreover, this compound was not mutagenic at any of the concentrations evaluated, exhibited a favorable in silico ADMET profile and showed a low potential for hepatotoxicity, as evidenced by the high values of CC50 in HepG2 cells. Furthermore, compared to BZN, derivative 8 showed a higher rate of conversion by nitroreductase and was metabolized three times more quickly when both compounds were tested at a concentration of 50 µM. The results obtained by the enzymatic evaluation and molecular docking studies suggest that, as planned, nitroazole derivatives may utilize the nitroreductase metabolism pathway as their main mechanism of action against Trypanosoma cruzi. In summary, we have successfully identified and characterized new nitrotriazole analogs, demonstrating their potential as promising candidates for the development of Chagas disease drug candidates that function via nitroreductase activation, are considerably selective and show no mutagenic potential.

Fitness-Dependent, Mild Mutagenic Activity of Sofosbuvir for Hepatitis C Virus.

The concept of a mild mutagen was coined to describe a minor mutagenic activity exhibited by some nucleoside analogues that potentiated their efficacy as antiretroviral agents. In the present study, we report the mild mutagen activity of sofosbuvir (SOF) for hepatitis C virus (HCV). Serial passages of HCV in human hepatoma cells, in the presence of SOF at a concentration well below its cytotoxic concentration 50 (CC50) led to pre-extinction populations whose mutant spectra exhibited a significant increase of C→U transitions, relative to populations passaged in the absence of SOF. This was reflected in an increase in several diversity indices that were used to characterize viral quasispecies. The mild mutagenic activity of SOF was largely absent when it was tested with isogenic HCV populations that displayed high replicative fitness. Thus, SOF can act as a mild mutagen for HCV, depending on HCV fitness. Possible mechanisms by which the SOF mutagenic activity may contribute to its antiviral efficacy are discussed.

Mutation signature filtering enables high-fidelity RNA structure probing at all four nucleobases with DMS.

Chemical probing experiments have transformed RNA structure analysis, enabling high-throughput measurement of base-pairing in living cells. Dimethyl sulfate (DMS) is one of the most widely used structure probing reagents and has played a pivotal role in enabling next-generation single-molecule probing analyses. However, DMS has traditionally only been able to probe adenine and cytosine nucleobases. We previously showed that, using appropriate conditions, DMS can also be used to interrogate base-pairing of uracil and guanines in vitro at reduced accuracy. However, DMS remained unable to informatively probe guanines in cells. Here, we develop an improved DMS mutational profiling (MaP) strategy that leverages the unique mutational signature of N1-methylguanine DMS modifications to enable high-fidelity structure probing at all four nucleotides, including in cells. Using information theory, we show that four-base DMS reactivities convey greater structural information than current two-base DMS and SHAPE probing strategies. Four-base DMS experiments further enable improved direct base-pair detection by single-molecule PAIR analysis, and ultimately support RNA structure modeling at superior accuracy. Four-base DMS probing experiments are straightforward to perform and will broadly facilitate improved RNA structural analysis in living cells.

A study on Amygdalin's genotoxicological safety and modulatory activity in human peripheral lymphocytes in vitro.

Amygdalin (AMY), a plant secondary metabolite containing nitrile, is a major component of the seeds of Rosaceae family plants. It is known that this compound has many pharmacological activities such as cancer prevention, antipyretic, and cough suppressant. In this study, the genotoxic and modulatory effects of amygdalin were assessed by chromosomal aberration (CA), sister chromatid exchange (SCE), and cytokinesis-block micronucleus assay (CBMN) assays using human peripheral lymphocytes (HPLs) in the absence and presence of metabolic activator (S9 mix). Lymphocytes were exposed to various concentrations of amygdalin (0.86, 1.72, 3.43, 6.86, and 13.75 µg/mL) alone and in combination with mitomycin-C (MMC, 0.20 µg/mL) or cyclophosphamide (CP, 12 µg/mL). The mitotic index (MI), replication index (RI), cytokinesis-block proliferation index (CBPI), and cytostasis were also evaluated to determine cytotoxicity. Amygdalin alone did not exhibit genotoxic and cytotoxic effects at all the tested concentrations both in the absence and presence of the S9 mix. In contrast, amygdalin significantly reduced the frequencies of CA (especially at 48 h treatments), SCE, and MN (except 0.86 µg/mL in pre- and simultaneous treatment) induced by MMC in all the tested concentrations and treatment protocols. It has also considerably decreased CP-induced CA and SCE frequencies at all the concentrations (except 0.86 µg/mL) in simultaneous treatment. This study demonstrated that amygdalin alone was not genotoxic, on the contrary, it has revealed modulatory effects against chemotherapy agents that induced genomic damage in human lymphocytes, suggesting its chemopreventive potential.

Toxicological potential of Aloysia gratissima: Insights from chemical analysis and in vitro studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Aloysia gratissima leaves are popularly used to treat respiratory, digestive, and nervous system disorders. Several studies have been carried out to determine the biological activity of A. gratissima, such as its antibacterial and anti-edematogenic activities, but despite the beneficial uses of A. gratissima, few studies have examined the toxicological profile of this plant. AIM OF THE STUDY: This study aimed to determine the chemical composition, cytotoxic, genotoxic, mutagenic potential, and antioxidant activity of an aqueous extract of A. gratissima leaves (AG-AEL). MATERIAL AND METHODS: The phytochemical constitution of AG-AEL was assessed by colorimetric analyses and High-performance liquid chromatography (HPLC). The inorganic elements were detected by Particle-Induced X-ray Emission (PIXE). The antioxidant, cytotoxicity, genotoxic, and mutagenic activities were evaluated in vitro by Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH), Sulforhodamine B (SRB) assay, comet assay, and Salmonella/microsome assays. RESULTS: AG-AEL indicated the presence of terpenoids, flavonoids, and phenolic acids. HPLC detected rutin at 2.41 ± 0.33 mg/100 mg. PIXE analysis indicated the presence of Mg, Si, P, S, K, Ca, Mn, and Zn. The 50% inhibitory concentration was 84.17 ± 3.17 µg/mL in the DPPH assay. Genotoxic effects were observed using the Comet assay in neuroblastoma (SH-SY5Y) cells and mutations were observed in TA102 and TA97a strains. The extract showed cytotoxic activities against ovarian (OVCAR-3), glioblastoma (U87MG), and colon (HT-29) cancer cell lines. CONCLUSIONS: In conclusion, AG-AEL increased DNA damage, induced frameshift, and oxidative mutations, and showed cytotoxic activities against different cancer cells. The in vitro toxicological effects observed suggest that this plant preparation should be used with caution, despite its pharmacological potential.

Haemato-biochemical, mutagenic, and histopathological changes in Oreochromis niloticus exposed to BTX.

The study of the DNA damage response in erythrocytes after exposure to volatile organic compounds (VOCs) can present evidence for its potential effect as genotoxic- biomarkers for environmental pollution. Although VOCs are dangerous pollutants, still little is known about hemotoxic, cytotoxic, and genotoxic effects of such pollutants on fish. We optimized an assay method for apoptosis and DNA damage in erythrocytes of adult tilapia fish after 15 days exposure to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L). The highest level of apoptosis and DNA damage were recorded in benzene-exposed fish, as was the highest level of histopathological alterations in gills, liver, and kidney. The imbalance of the antioxidants profile explained the stress-case reported in exposed fish. These results suggest that hemotoxic, cytotoxic, genotoxic, and tissue damage were recorded after exposure to BTX in Oreochromis niloticus.

Atypical Mutational Spectrum of SARS-CoV-2 Replicating in the Presence of Ribavirin.

We report that ribavirin exerts an inhibitory and mutagenic activity on SARS-CoV-2-infecting Vero cells, with a therapeutic index higher than 10. Deep sequencing analysis of the mutant spectrum of SARS-CoV-2 replicating in the absence or presence of ribavirin indicated an increase in the number of mutations, but not in deletions, and modification of diversity indices, expected from a mutagenic activity. Notably, the major mutation types enhanced by replication in the presence of ribavirin were A→G and U→C transitions, a pattern which is opposite to the dominance of G→A and C→U transitions previously described for most RNA viruses. Implications of the inhibitory activity of ribavirin, and the atypical mutational bias produced on SARS-CoV-2, for the search for synergistic anti-COVID-19 lethal mutagen combinations are discussed.

In vitro cytogenotoxic evaluation of aripiprazole on human peripheral lymphocytes and computational molecular docking analysis.

Two different drug groups, typical (classic) and atypical (new), are used in the treatment of schizophrenia. Aripiprazole, an atypical antipsychotic chemical, is the active ingredient of the drug Abilify. This study was conducted to determine the possible genotoxic effect of aripiprazole. For this purpose, four different doses of aripiprazole (5; 10; 20, and 40 µg/mL) were examined with Chromosome Abnormality (CA), Sister Chromatid Exchange (SCE), Micronucleus (MN) tests. Based on these tests, Proliferation Index (PI), Percent Abnormal Cells (AC), Mitotic Index (MI), Micronuclear Binuclear Cell (MNBN), and Nuclear Division Index (NDI) levels were determined in human peripheral lymphocytes treated for 24 and 48 hours. Also, to determine possible binding sites of Aripiprazole on B-DNA molecular docking analysis was performed using AutoDock 4.0 (B-DNA dodecamer, PDB code: 1BNA). Aripiprazole binds to B-DNA with a very significant free binding energy (-11.88 Kcal/mol). According to our study, aripiprazole did not significantly change SCE, CA, AC percentage, MN frequencies when compared with control. According to these results, aripiprazole does not have a genotoxic effect. At the same time, no significant change was observed in the PI, MI, and NDI frequencies when compared with the control. In line with these results, it was observed that the use of aripiprazole in the treatment of schizophrenia did not pose any acute genotoxic and cytotoxic risk.

Copper(II) Complex Containing 4-Fluorophenoxyacetic Acid Hydrazide and 1,10-Phenanthroline: A Prostate Cancer Cell-Selective and Low-Toxic Copper(II) Compound.

Prostate Cancer (PCa) is the second leading cause of cancer-related deaths among men worldwide. The treatment of advanced cases is based on chemotherapy, which lacks specificity and efficacy, due to severe side effects and resistance to the traditional drugs. Copper complexes have shown antitumoral efficacy and low toxicity, being considered a promising class of metal-based drugs for the treatment of malignant neoplasms. Thus, the present study aimed to evaluate the cellular effects of a copper(II) complex with 4-fluorophenoxyacetic acid hydrazide and 1,10-phenanthroline (1) on PCa cell lines, as well as the mutagenic/recombinogenic and anticarcinogenic potential of 1 in Drosophila melanogaster. PNT-2 (non-tumorigenic), LNCaP (hormone-responsive PCa) and PC-3 (androgen-independent PCa) cells were cultured, and cytotoxicity was assessed using the MTT assay. The expression levels of the proliferation markers Ki-67 and Cyclin D1 were analyzed by flow cytometry. Furthermore, the Somatic Mutation and Recombination Test (SMART) and the Epithelial Tumor Test (ETT) were performed. Complex 1 was selective to LNCaP cells, significantly reducing Ki-67 and Cyclin D1 expression levels. Sub-toxic concentrations of complex 1 were defined by the toxicity test in D. melanogaster, and no mutagenic/recombinogenic/carcinogenic effects were observed. Anticarcinogenic potential was observed in D. melanogaster, suggesting modulating activity of the complex 1 against Doxorubicin, a drug used as control by its carcinogenic properties. Therefore, complex 1 is a possible starting point for the development of new antitumor agents for the treatment of PCa.

Mutagenic effect of a commercial fungicide on Rana catesbeiana and Leptodactylus latrans tadpoles.

We have examined the mutagenic effects of the fungicide Elatus® on tadpoles of Rana catesbeiana and Leptodactylus latrans. Sixty-four tadpoles of each species have been exposed to three concentrations of Elatus® (10, 20, and 50 µg/L-1) during 96 hours. We've carried out the micronucleus test (MN) and erythrocyte nuclear abnormalities (ENAs) in 32 tadpoles of each species, the others 32 tadpoles of each species remained in a solution free of Elatus® during 96 hours, in order to assess the ability to recover from the damage caused by the fungicide. There was significant difference in MNs frequency between the treatment exposed to 50µg/L-1 and the control groups for R. catesbeiana, while for L. latrans, we've found difference between the treatment of 20 µg/L-1, followed by a period without exposure to the contaminant and the control group when all ENAs were analyzed. When we compared the two species, R. catesbeiana presented a higher frequency of MNs than L. latrans in the treatment exposed to 50 µg/L-1of the fungicide. Our findings highlight the need to monitor amphibians in places where this product is widely used.

Recommendations and quality criteria for micronucleus studies with humans.

Micronucleus (MN) analyses in peripheral blood lymphocytes and exfoliated cells from different organs (mouth, nose, bladder and cervix) are at present the most widely used approaches to detect damage of genetic material in humans. MN are extranuclear DNA-containing bodies, which can be identified microscopically. They reflect structural and numerical chromosomal aberrations and are formed as a consequence of exposure to occupational, environmental and lifestyle genotoxins. They are also induced as a consequence of inadequate intake of certain trace elements and vitamins. High MN rates are associated with increased risk of cancer and a range of non-cancer diseases in humans. Furthermore, evidence is accumulating that measurements of MN could be a useful tool for the diagnosis and prognosis of different forms of cancer and other diseases (inflammation, infections, metabolic disorders) and for the assessment of the therapeutic success of medical treatments. Recent reviews of the current state of knowledge suggest that many clinical studies have methodological shortcomings. This could lead to controversial findings and limits their usefulness in defining the impact of exposure concentrations of hazardous chemicals, for the judgment of remediation strategies, for the diagnosis of diseases and for the identification of protective or harmful dietary constituents. This article describes important quality criteria for human MN studies and contains recommendations for acceptable study designs. Important parameters that need more attention include sufficiently large group sizes, adequate duration of intervention studies, the exclusion of confounding factors which may affect the results (sex, age, body mass index, nutrition, etc.), the evaluation of appropriate cell numbers per sample according to established scoring criteria as well as the use of proper stains and adequate statistical analyses.