<p>In Sweden approximately 2800 new lung cancer patients are diagnosed every year. Radiotherapy is used with curative intention in certain groups of patients. The aim of this thesis is to study the basis of differences in radioresistance and the possibility to predict response to radiotherapy.</p><p>In the first study we investigated, using the comet assay, four lung cancer cell lines with different sensitivity towards radiation. A clear dose-response relationship for radiation-induced DNA single strand and double strand breaks were found. All cell lines showed a remarkably efficient repair of both the DNA single strand and double strand breaks one hour after irradiation. However, further studies in one radioresistant and one radiosensitive cell line demonstrated that repair during the first 15 min had the best accordance with radiosensitivity measured as surviving fraction.</p><p>In the second and third study, sequencing studies of the p53 gene were performed on cell lines as well as on tumour material. Cell lines that were expressing a mutation in exon 7 were associated with increased radiosensitivity compared with tumor cell lines with mutations in other exons. In the clinical study, 10 patients were found to be mutated in the p53 gene whereas the other 10 patients were not. No correlation to clinical parameters could be drawn.</p><p>In the fourth study, serum from 67 patients with a confirmed diagnosis of non-small cell lung cancer was investigated for the presence of p53 antibodies. P53 antibodies in sera, taken prior to radiation treatment, were associated with increased survival.</p><p>The summary of this thesis indicates that the p53 gene has an impact on the effect of radiotherapy in lung cancer. The presence of p53 antibodies might be of clinical interest for predicting survival after radiotherapy. Further studies on the importance of the p53 gene on early repair are of interest. </p>

Cyclotides are plant proteins with a unique topology, defined as the cyclic cystine knot motif. The motif endows cyclotides with exceptional chemical and biological stability. They also exhibit a wide range of biological activities including insecticidal, cytotoxic, anti-HIV and antimicrobial effects. Hence, cyclotides have become potential candidates in the development of peptide-based drugs; either as scaffolds to stabilize susceptible peptide sequences or as drugs by their own right. In this thesis, important parameters that could be inputs toward this development have been tuned. An extraction protocol that can be extended to industrial scale production of the cyclotides from natural sources was developed; accordingly, a single maceration with hydroalcoholic solutions of medium polarity represented an optimum extraction method. Moreover, it was shown that investigating the cyclotide content of cyclotide-bearing plants from diverse environments is a promising approach for extending the knowledge of both structural and biological diversity of these proteins. Five novel cyclotides with new sequence diversity were isolated and characterized from a violet that grows on Ethiopian highlands at an altitude of 3400 m. One of the areas where the cyclotide framework has attracted interest is the development of stable antimicrobial peptides. A stability study was carried out to determine the stability of the cyclotide framework in a cocktail of bacterial proteases and serum where the native forms of tested cyclotides exhibited high stability profile. Understanding the modes of cyclotide-cell interaction is certainly an important factor for the potential development of cyclotide-based drugs. Cellular studies were carried out using the comet assay and microautoradiography. A bell-shaped dose response curve was obtained for the DNA damaging effect of the cyclotides in the comet assay, which was the first toxicological assay of its kind on this class of proteins. The microautoradiography study revealed that the cyclotides penetrate into the cells even at cytotoxic concentrations. From previous reports, it was known that the cyclotides interact with membranes; the cellular studies in this thesis added to this knowledge by clearly demonstrating that these proteins have multiple modes of action.

In Sweden approximately 2800 new lung cancer patients are diagnosed every year. Radiotherapy is used with curative intention in certain groups of patients. The aim of this thesis is to study the basis of differences in radioresistance and the possibility to predict response to radiotherapy. In the first study we investigated, using the comet assay, four lung cancer cell lines with different sensitivity towards radiation. A clear dose-response relationship for radiation-induced DNA single strand and double strand breaks were found. All cell lines showed a remarkably efficient repair of both the DNA single strand and double strand breaks one hour after irradiation. However, further studies in one radioresistant and one radiosensitive cell line demonstrated that repair during the first 15 min had the best accordance with radiosensitivity measured as surviving fraction. In the second and third study, sequencing studies of the p53 gene were performed on cell lines as well as on tumour material. Cell lines that were expressing a mutation in exon 7 were associated with increased radiosensitivity compared with tumor cell lines with mutations in other exons. In the clinical study, 10 patients were found to be mutated in the p53 gene whereas the other 10 patients were not. No correlation to clinical parameters could be drawn. In the fourth study, serum from 67 patients with a confirmed diagnosis of non-small cell lung cancer was investigated for the presence of p53 antibodies. P53 antibodies in sera, taken prior to radiation treatment, were associated with increased survival. The summary of this thesis indicates that the p53 gene has an impact on the effect of radiotherapy in lung cancer. The presence of p53 antibodies might be of clinical interest for predicting survival after radiotherapy. Further studies on the importance of the p53 gene on early repair are of interest.

Single cell gel electrophoresis (SCGE), more commonly known as the Comet assay, is an uncomplicated, affordable and versatile method for investigating DNA damage and repair. Existing comet–assay based methods were modified and applied in this study in order to examine the effects of different perturbations on the DNA repair capacity of different samples. Mitochondrial functioning has a vast effect on overall cell physiology and does not simply involve the production of energy in the form of ATP that sustains common biological processes, but is also associated with important cellular occurrences such as apoptosis and ROS production. It is suggested that a change in mitochondrial function may lead to extensive ROS production which may negatively affect macromolecules, including proteins involved in DNA repair pathways, and impaired energy formation which in turn may hamper the proper occurrence of energy driven processes. Complex I and ?III knock–down systems established in 143B cells are used to investigate the effect that perturbations of the energy metabolism may have on DNA repair capacity. Metallothioneins (MTs) are known to play an imperative role in trace element homeostasis and detoxification of metals and are effective ROS scavengers. The prooxidant environment that heavy metal imbalance causes may result in mutagenesis and transformation through DNA damage. It is suggested that an imbalance in the metal homeostasis caused by MT knock–out may create an environment favourable for DNA damage formation and at the same time impair DNA repair pathways. Because of the multi–functionality and involvement of metallothioneins in such a wide variety of biological processes, it was considered interesting and essential to extend the investigation on the effect of the absence of metallothioneins on DNA repair. A metallothionein I and ?II knock–out mouse model is employed to determine the effect of MT knock–out on DNA repair capacity. It was clear from the results obtained that transfection of cells, as used to investigate a perturbation in the energy metabolism in 143B cells, has an impairing effect on DRC. It was also confirmed that metallothioneins play an important and diverse role in cell biology since the absence thereof inhibits both BER and NER. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.

Single cell gel electrophoresis (SCGE), more commonly known as the Comet assay, is an uncomplicated, affordable and versatile method for investigating DNA damage and repair. Existing comet–assay based methods were modified and applied in this study in order to examine the effects of different perturbations on the DNA repair capacity of different samples. Mitochondrial functioning has a vast effect on overall cell physiology and does not simply involve the production of energy in the form of ATP that sustains common biological processes, but is also associated with important cellular occurrences such as apoptosis and ROS production. It is suggested that a change in mitochondrial function may lead to extensive ROS production which may negatively affect macromolecules, including proteins involved in DNA repair pathways, and impaired energy formation which in turn may hamper the proper occurrence of energy driven processes. Complex I and ?III knock–down systems established in 143B cells are used to investigate the effect that perturbations of the energy metabolism may have on DNA repair capacity. Metallothioneins (MTs) are known to play an imperative role in trace element homeostasis and detoxification of metals and are effective ROS scavengers. The prooxidant environment that heavy metal imbalance causes may result in mutagenesis and transformation through DNA damage. It is suggested that an imbalance in the metal homeostasis caused by MT knock–out may create an environment favourable for DNA damage formation and at the same time impair DNA repair pathways. Because of the multi–functionality and involvement of metallothioneins in such a wide variety of biological processes, it was considered interesting and essential to extend the investigation on the effect of the absence of metallothioneins on DNA repair. A metallothionein I and ?II knock–out mouse model is employed to determine the effect of MT knock–out on DNA repair capacity. It was clear from the results obtained that transfection of cells, as used to investigate a perturbation in the energy metabolism in 143B cells, has an impairing effect on DRC. It was also confirmed that metallothioneins play an important and diverse role in cell biology since the absence thereof inhibits both BER and NER. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.

Existem evidências crescentes indicando a associação entre dietas ricas em frutas e vegetais e a diminuição da incidência de câncer. O suco de laranja (OJ) pode ser incluído entre os alimentos com potencial quimioprotetor e seu estudo é muito relevante pelo amplo consumo desta bebida. O OJ possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. A vitamina C (Vit C) é um dos nutrientes mais abundantes no OJ, e o único nutriente que pode ser provido em quantidade superior à recomendação diária por uma única porção de 200 mL de OJ. A Vit C, a exemplo de outros componentes do OJ, pode ser tanto benéfica quanto maléfica para os sistemas biológicos, dependendo do contexto metabólico. Neste sentido, vários nutrientes presentes no OJ têm sido identificados como mutagênicos ou carcinogênicos, especialmente quando administrados de forma isolada. Este estudo utilizou o ensaio Cometa alcalino em sangue de camundongos (in vivo) para avaliar: 1) a genotoxicidade do OJ e da Vit C; 2) a genotoxicidade do FeSO4 e do CuSO4: 3) o efeito modulador do OJ e da Vit C sobre a genotoxicidade do FeSO4 e CuSO4, bem como do metilmetanosulfonato (MMS) e da ciclofosfamida (CP). A versão alcalina do ensaio Cometa foi utilizada para avaliar o dano no DNA em células brancas do sangue periférico de camundongos. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. processado e armazenado de forma a preservar o seu potencial biológico é um alimento sugerido como uma das porções de uma dieta equilibrada (contendo pelo menos 5 porções de frutas e vegetais), recomendada para uma vida saudável e longeva. / Evidence indicates an association between diets rich in fresh fruit and vegetables and a decreased incidence of cancers. Orange juice (OJ) is a food with chemoprotective potential highly relevant for study due to its widespread consumption. OJ is composed of several nutrients and bioactive compounds with antioxidant, antimutagenic, anticarcinogenic and antiathrerogenic activities. Vitamina C (Vit C) is the most abundant nutrient in OJ, and the only one that can be provided in amounts higher that the daily recommended intake by a single portion of OJ (200 mL). Vit C, like other components of OJ, can be either benefical or noxious for biological system, depending of their metabolic context. Indeed, some components of juices have been identified as mutagenic or carcinogenic when isolated. In this study we tested by comet assay in mice in vivo: 1) the genotoxicity of orange juice (OJ) and vitamin C (Vit C); 2) the genotoxicity of FeSO4 and CuSO4: 3) the modulator effect of orange juice and Vit C over genotoxicity of FeSO4 and CuSO4, as well as over methyl methanesulfonate (MMS) and cyclophosphamide (CP). We used the alkaline version of the comet assay to assess DNA damage in peripheral white blood cells of mice. Moreover, the levels of iron and copper in the whole blood and liver of the mice treated with this metals were evaluated by PIXE (Particle-Induced X-ray Emission). Groups of at least 6 mice (half of each gender) were orally given a single dose of either water (control), CP, MMS, FeSO4 or CuSO4. OJ (0.1 mL/Kg) was given either before (pre-treatment) or after (post-treatment) administration of the test substances. Vit C (1 and 30 mg/Kg) was only administered after treatment (post-treatment). DNA damage was evaluated 24 and 48 h after the beginning of the treatment. After 24 h, OJ induced a slight increase in DNA damage and Vit C was genotoxic (30 mg/Kg > 1 mg/Kg). Double treatment with Vit C (at 0 and 24 h) induced a cumulative genotoxic response at 48 h, more intense for the higher dose. FeSO4 and CuSO4 were genotoxic after 24 h and significant DNA damage repair was observed after 48 h of treatment. OJ pre-treatment reduced the genotoxicity of FeSO4 (preventive effect). OJ had a preventive effect over the genotoxicity of CuSO4. OJ post-treatment also reduced the genotoxicity of CuSO4 (restorative effect). OJ had both protective and reparative effects over MMS. OJ had only a reparative effect over CP. Both doses of Vit C enhanced DNA damage caused by FeSO4 and CuSO4. DNA damage caused by MMS was significantly reduced by the lower dose, but not by the higher dose of Vit C. For CP, the DNA damage was not affected by the post-treatment with any of the doses of Vit C. PIXE analysis indicated a positive correlation between DNA damage and the hepatic levels of iron and a negative correlation between whole blood copper and DNA damage. A negative correlation between hepatic iron and whole blood copper content was also seen in the treatment with both ferrous and cupric sulfates. These results point a dynamic interaction between the genotoxicity and the tecidual fate of iron and copper. Vit C and the other components of OJ have several biological effects, including: 1) action as targets for toxicants; 2) influence in drug metabolization/detoxification; and 3) effect in DNA repair and homeostasis. Moreover, Vit C and transition metals, particularly copper and iron, can induce oxidative stress; however, they can also play roles in antioxidant defense system, being a DNA repair modulators. Further data from other treatment schedules are needed to shed light upon the beneficial/noxious effects of OJ as a complex mixture, as well as of its compounds in genomic stability. Indeed, one glass of fresh or adequate processed and stored OJ can be among the options for the daily 5 portions (or even more) of fruits and vegetables recommended for a health and longevity.

O crack é um subproduto da cocaína obtido a partir da pasta de coca acrescida do bicarbonato de sódio, sendo comercializado na forma de pequenas pedras porosas. No Brasil, o consumo de crack tem sido alvo de grande preocupação devido sua expressiva expansão em várias regiões, sendo que o aumento da prevalência do seu consumo vem sendo amplamente documentado nos últimos anos. A dependência de crack é a causa mais prevalente de internação por uso de cocaína. Há uma necessidade imediata de estudos que se direcionem para esta população. A presente pesquisa pretende demonstrar evidências capazes de contribuir para o entendimento dos mecanismos envolvidos na ação do psicotrópico crack sobre o DNA, bem como oferecer dados que auxiliem no desenvolvimento de tratamentos para pacientes usuários abusivos desta droga. Este estudo teve como objetivo avaliar o dano ao DNA e a capacidade de reparo, em 31 indivíduos usuários ativos de crack, relacionando-os com um grupo controle com 40 participantes. O trabalho foi desenvolvido através de voluntários recém internados na Clínica Marcelo Campos em São Leopoldo. Foram coletadas amostras em três momentos (internação, 48h após e ao término do tratamento) e submetidas às técnicas de micronúcleo e cometa. Dentre os resultados desta avaliação, foram evidenciados índices de dano significativamente diferentes entre os grupos nas técnicas de micronúcleos e cometa, e entre os períodos de coleta na técnica de cometa. Os valores obtidos para o índice de dano de DNA da técnica do cometa nos três momentos de avaliação revelaram uma diminuição estatisticamente significativa apenas após o término do tratamento. Em relação à utilização concomitante de outras substâncias, o consumo de tabaco ocorreu em 68% dos indivíduos, maconha em 71% e cocaína em 32%, sendo que 19% faziam uso concomitante de todas as drogas mencionadas. Houve correlação com o tempo de uso do tabaco e o índice de dano (P=0,043), MN (P=0,017) e NBP (P=0,023) em determinados momentos. O consumo de álcool ocorreu em 61,29% dos participantes, não havendo correlação estatisticamente significativa com os marcadores de dano. A idade e o tempo de utilização do crack não apresentaram associação ao índice de dano. Houve associação significativa entre o consumo de chimarrão (Ilex paraguaiensis) e MN (P= 0,045). Estudos associando o crack com dano ao DNA são, ainda, escassos. Este trabalho buscou acrescentar informações quanto ao potencial danoso desta substância. / Crack is a by-product of cocaine resulting from the addition of sodium bicarbonate to cocaine base paste, being sold in the form of small, porous rocks. In Brazil, the consumption of crack has been the subject of great concern due to its significant expansion in various regions, thus the increasing prevalence of drug use has been documented in recent years. The dependence of crack is the most prevalent cause of hospitalization due to cocaine use, supporting an immediate need for studies to target this population. This research aims to demonstrate evidence that can contribute to the understanding of the mechanisms involved in the action of psychotropic Crack on DNA, as well as provide data to assist in development of treatments for patients who are drug abusers. This study aimed to assess the damage and DNA repair capacity in 31 individuals who are active users of crack, comparing them to a control group of 40 participants. The study was conducted by volunteers newly admitted to the Clinic Marcelo Campos in São Leopoldo. Samples were collected at three time points (at admission, 48 hours latter and at the end of treatment) and subjected to the comet and micronucleus techniques. Among the results of this assessment damage indices were evident and significantly different between groups in the comet and micronucleus techniques, and between sampling periods for the comet technique. The values obtained for the rate of DNA damage in the comet technique in all three time points revealed a statistically significant decrease only after the end of treatment. Regarding the concomitant use of other substances, no significant association was found with the results. Tobacco consumption occurred in 68% of subjects, marijuana in 71% and cocaine in 32%, being 19% users of all drugs mentioned. There was a correlation over time of tobacco use and the damage index (P = 0.043), MN (P = 0.017) and NBP (P = 0.023) at certain time points.. Alcohol consumption occurred in 61.29% of the participants, there was no statistically significant correlation with markers of damage.The age and duration of use were not associated to the crack damage index. There was a significant association between the consumption of yerba mate (Ilex paraguaiensis) and MN. (P = 0.045). Studies associating the crack with DNA damage are still scarce. This study brings additional information about the potential harmful of substance.

Highly profitable black caviar market and the depletion of wild sturgeon stocks warrant improvements in sturgeon aquaculture. Therefore, chromosomal manipulations, particularly gynogenesis, are focused on for increasing the ratio of females over males in progeny. The present study focused on optimizing chromosomal manipulations in sturgeons, particularly gynogenesis. The reasons of low survival rates were analyzed and the critical steps of gynogenesis induction processes were optimized. In addition, alternative ways of DNA inactivation in sperms were investigated, as well as the influence of native light-dependent DNA repair mechanisms on gynogenesis induction. Methods of interspecific gynogenesis usage for simplifying gynogenetic progeny separation were also proposed. Spectrophotometry analysis was used to investigate the ability of UV light, as the most common DNA inactivating agent, to penetrate into sperm. In addition, investigation of UV-irradiated sperm motility and results of partial gynogenesis induction showed that low transparency of sperms for UV-light can cause significant heterogeneity of UV-irradiation. As a result, a proper dilution of sperm was suggested as a critical step for homogeneous UV-irradiation of samples. Gynogenesis in sterlet was induced with chemical agents that damage sperm DNA, as an alternative to UV irradiation for applied in large-scale production of gynogenotes. All tested substances showed ability to inactivate DNA in spermatozoa, and thus producing gynogenotes. Negative impact of treatments with chemical agents on the sperm motility was observed. Subsequently, these treatments had a low efficiency of gynogenesis induction. The highest percentage of produced gynogenetic larvae 19.8 ? 8.9% was obtained by treatment with aminomethyl-4,5?,8-trimethylpsoralen (AMT) at 50 ?M followed by UV-A (360 nm) irradiation at dose of 900 J/m2. Therefore, this treatment could be used as a substitute for commonly used UV-C irradiation, e.g., in the case of large volumes of sperm. Detailed investigation of photoreactivation in sturgeon sperm revealed a significant level of light-dependent DNA restoration in sperms irradiated with high doses of UV-C light. Induction of gynogenesis with UV-C irradiation followed by exposure to visible light resulted in significant deviations from the typical Hertwig effect. In contrast, the red light with a wavelength of more than 600 nm did not result in decreased DNA damage, instead a moderate increase in damage was observed, i.e., it did not induce photoreactivation. Therefore, the use of infrared light to illuminate work stations during the induction of gynogenesis is suggested. The use of interspecific gynogenesis, particularly gametes of sturgeon species with different ploidy levels, was suggested as a way to simplify the separation of gynogenotes. In addition, application of this method allowed studying the effectiveness of DNA-inactivation and ploidy restoration treatments separately, as well as evaluation of fitness parameters and survival rates in each group of progeny without the physical separation of fish. Finally, the protocol for tetraploidization in sterlet was optimized for the prospective using tetraploid individuals for the induction of gynogenesis and androgenesis with diploid eggs and sperm. In conclusion, the described methods and protocols allowed gynogenesis induction in sturgeons with a survival rate sufficient for aquaculture, taking into consideration their high fertility, although further studies of the consequences of this treatment on fish is required.

Existem evidências crescentes indicando a associação entre dietas ricas em frutas e vegetais e a diminuição da incidência de câncer. O suco de laranja (OJ) pode ser incluído entre os alimentos com potencial quimioprotetor e seu estudo é muito relevante pelo amplo consumo desta bebida. O OJ possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. A vitamina C (Vit C) é um dos nutrientes mais abundantes no OJ, e o único nutriente que pode ser provido em quantidade superior à recomendação diária por uma única porção de 200 mL de OJ. A Vit C, a exemplo de outros componentes do OJ, pode ser tanto benéfica quanto maléfica para os sistemas biológicos, dependendo do contexto metabólico. Neste sentido, vários nutrientes presentes no OJ têm sido identificados como mutagênicos ou carcinogênicos, especialmente quando administrados de forma isolada. Este estudo utilizou o ensaio Cometa alcalino em sangue de camundongos (in vivo) para avaliar: 1) a genotoxicidade do OJ e da Vit C; 2) a genotoxicidade do FeSO4 e do CuSO4: 3) o efeito modulador do OJ e da Vit C sobre a genotoxicidade do FeSO4 e CuSO4, bem como do metilmetanosulfonato (MMS) e da ciclofosfamida (CP). A versão alcalina do ensaio Cometa foi utilizada para avaliar o dano no DNA em células brancas do sangue periférico de camundongos. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. processado e armazenado de forma a preservar o seu potencial biológico é um alimento sugerido como uma das porções de uma dieta equilibrada (contendo pelo menos 5 porções de frutas e vegetais), recomendada para uma vida saudável e longeva. / Evidence indicates an association between diets rich in fresh fruit and vegetables and a decreased incidence of cancers. Orange juice (OJ) is a food with chemoprotective potential highly relevant for study due to its widespread consumption. OJ is composed of several nutrients and bioactive compounds with antioxidant, antimutagenic, anticarcinogenic and antiathrerogenic activities. Vitamina C (Vit C) is the most abundant nutrient in OJ, and the only one that can be provided in amounts higher that the daily recommended intake by a single portion of OJ (200 mL). Vit C, like other components of OJ, can be either benefical or noxious for biological system, depending of their metabolic context. Indeed, some components of juices have been identified as mutagenic or carcinogenic when isolated. In this study we tested by comet assay in mice in vivo: 1) the genotoxicity of orange juice (OJ) and vitamin C (Vit C); 2) the genotoxicity of FeSO4 and CuSO4: 3) the modulator effect of orange juice and Vit C over genotoxicity of FeSO4 and CuSO4, as well as over methyl methanesulfonate (MMS) and cyclophosphamide (CP). We used the alkaline version of the comet assay to assess DNA damage in peripheral white blood cells of mice. Moreover, the levels of iron and copper in the whole blood and liver of the mice treated with this metals were evaluated by PIXE (Particle-Induced X-ray Emission). Groups of at least 6 mice (half of each gender) were orally given a single dose of either water (control), CP, MMS, FeSO4 or CuSO4. OJ (0.1 mL/Kg) was given either before (pre-treatment) or after (post-treatment) administration of the test substances. Vit C (1 and 30 mg/Kg) was only administered after treatment (post-treatment). DNA damage was evaluated 24 and 48 h after the beginning of the treatment. After 24 h, OJ induced a slight increase in DNA damage and Vit C was genotoxic (30 mg/Kg > 1 mg/Kg). Double treatment with Vit C (at 0 and 24 h) induced a cumulative genotoxic response at 48 h, more intense for the higher dose. FeSO4 and CuSO4 were genotoxic after 24 h and significant DNA damage repair was observed after 48 h of treatment. OJ pre-treatment reduced the genotoxicity of FeSO4 (preventive effect). OJ had a preventive effect over the genotoxicity of CuSO4. OJ post-treatment also reduced the genotoxicity of CuSO4 (restorative effect). OJ had both protective and reparative effects over MMS. OJ had only a reparative effect over CP. Both doses of Vit C enhanced DNA damage caused by FeSO4 and CuSO4. DNA damage caused by MMS was significantly reduced by the lower dose, but not by the higher dose of Vit C. For CP, the DNA damage was not affected by the post-treatment with any of the doses of Vit C. PIXE analysis indicated a positive correlation between DNA damage and the hepatic levels of iron and a negative correlation between whole blood copper and DNA damage. A negative correlation between hepatic iron and whole blood copper content was also seen in the treatment with both ferrous and cupric sulfates. These results point a dynamic interaction between the genotoxicity and the tecidual fate of iron and copper. Vit C and the other components of OJ have several biological effects, including: 1) action as targets for toxicants; 2) influence in drug metabolization/detoxification; and 3) effect in DNA repair and homeostasis. Moreover, Vit C and transition metals, particularly copper and iron, can induce oxidative stress; however, they can also play roles in antioxidant defense system, being a DNA repair modulators. Further data from other treatment schedules are needed to shed light upon the beneficial/noxious effects of OJ as a complex mixture, as well as of its compounds in genomic stability. Indeed, one glass of fresh or adequate processed and stored OJ can be among the options for the daily 5 portions (or even more) of fruits and vegetables recommended for a health and longevity.

Made available in DSpace on 2014-06-11T19:22:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-31Bitstream added on 2014-06-13T19:08:41Z : No. of bitstreams: 1 carita_r_me_rcla.pdf: 1452863 bytes, checksum: 811f7ba6f705a7dcdc689faac40ddbc1 (MD5) / A mutagenicidade é um efeito tóxico que danifica o material genético da célula, causando alterações no DNA ou no cromossomo. Existem inúmeras substâncias presentes em complexos de efluentes domésticos e industriais que podem causar sérios prejuízos no material genético. Testes biológicos de toxicidade e genotoxicidade são indispensáveis para estudos de monitoramento, que tem por finalidade avaliar a extensão da poluição ambiental e as reações dos organismos vivos frente a esta poluição. Águas que recebem descargas de diferentes fontes poluidoras, como efluentes industriais e urbanos, na sua maioria, são impactadas por misturas complexas compostas de químicos diversos. O córrego Santa Gertrudes e rios associados recebem efluentes industriais, de uma série de indústrias cerâmicas, e domésticos do município de Santa Gertrudes, SP. Os efluentes cerâmicos possuem efeito tóxico, sobretudo devido à presença de metais resultantes do processo de esmaltação dos revestimentos cerâmicos. As espécies Allium cepa e Oreochromis niloticus têm se mostrado bastante eficiente na avaliação da genotoxicidade ambiental. Neste trabalho foi avaliada a qualidade da água dos córregos Santa Gertrudes, Caju, Itaqui e do ribeirão Claro, por meio de testes desenvolvidos com estes bioindicadores. Pelos resultados obtidos, pudemos observar que os compostos presentes nas águas destes rios apresentam potencial tóxico, citotóxico, genotóxico e mutagênico para os dois organismos-teste. O teste com bulbos de A. cepa mostrou uma inibição no desenvolvimento das raízes, devido às substâncias tóxicas presente em águas coletadas após o despejo de efluentes. As amostras dos pontos correspondentes ao local de emissão de efluentes também induziram elevados índices de AC e MN em células meristemáticas de A. cepa, para todas as coletas realizadas. O ponto de coleta... / Mutagenicity is a toxic effect that damages the genetic material of the cell, causing alterations in either the DNA or the chromosome. There are several substances present in complexes of domestic and industrial effluents that may cause serious damage to the genetic material. Biological tests of toxicity and genotoxicity are essential for monitoring studies, which aims at assessing the extension of the environmental pollution and the reaction of the living organisms to this pollution. Waters that receive discharges from different sources of pollution, such as urban and industrial effluents, are mostly impacted by complex mixtures composed by several chemicals. Santa Gertrudes stream and associated rivers receive domestic effluents from the municipality of Santa Gertrudes (SP, Brazil) and industrial effluents from several ceramic industries. The ceramic effluents have toxic effects mainly due to the presence of metals resulting from the enameling process of ceramic coating. Allium cepa and Oreochromis niloticus species are very efficient in evaluating environmental genotoxicity resulting from pollution. In this study, the quality of the water of the Santa Gertrudes, Caju, Itaqui and Claro streams was assessed by tests developed with these bioindicators. Based on the results, we could observe that the compounds present in the waters are potencialy toxic, cytotoxic, genotoxic and mutagenic to both test organisms. The tests with bulbs of A. cepa showed an inhibition in root development due to the toxic substances present in the waters collected after the discharge of the effluents. Likewise, the samples from the effluent emission sites induced high indices of CA and MN in meristematic cells of A. cepa for all the collections made. The collection site located after the confluence of the Santa Gertrudes and Claro streams presented an increase in the alteration indices, especially for the August... (Complete abstract click electronic access below)