Analysis of nuclear maturation, DNA damage and repair gene expression of bovine oocyte and cumulus cells submitted to ionizing radiation'

Radiotherapy causes destruction of tumor cells, but also threatens the integrity and survival of surrounding normal cells. Then, woman submitted to irradiation for cancer treatment may present permanent ovary damage, resulting in impaired fertility. The objective of this study was to investigate the effects of therapeutic doses of ionizing radiation (IR), used for ovarian cancer treatment in humans, on bovine cumulus-oocyte complexes (COCs) as experimental model. Bovine ovaries were exposed to 0.9 Gy, 1.8 Gy, 3.6 Gy or 18.6 Gy IR, and then COCs were collected and used to evaluate: (a) oocyte nuclear maturation; (b) presence of phosphorylated H2A.X (γH2AX), as an indicator of DNA double-strand breaks (DSBs); and (c) expression of genes involved in DNA repair (TP53BP1, RAD52, ATM, XRCC6 and XRCC5) and apoptosis (BAX). The radiation doses tested in this study had no detrimental effects on nuclear maturation and did not increase γH2AX in the oocytes. However, IR treatment altered the mRNA abundance of RAD52 (RAD52 homolog, DNA repair protein) and BAX (BCL2-associated X protein). We conclude that although IR doses had no apparent effect on oocyte nuclear maturation and DNA damage, molecular pathways involved in DNA repair and apoptosis were affected by IR exposure in cumulus cells.(AU)

RADIOPROTEÇÃO E RADIOMITIGAÇÃO DO Ginkgo biloba EM CÉREBRO DE RATOS EXPOSTOS AOS RAIOS-X DE 6 MeV

O sistema nervoso é afetado de diversas formas pela exposição à radiação ionizante (RI), incluindo danos cognitivos e morfológicos. O estresse oxidativo, por exemplo, trata-se de um dos efeitos da RI e é caracterizado pelo desequilíbrio entre a produção de espécies reativas de oxigênio e mecanismos de defesa antioxidante. Portanto, a busca por radioprotetores se faz cada vez mais pertinente para minimizar esses efeitos adversos. Uma espécime proeminente nesse cenário, é o Ginkgo biloba (Gb) por se tratar de um antioxidante e por já ter demonstrado ser um neuroprotetor. Portanto, o presente trabalho teve como objetivo central avaliar a possível ação radioprotetora do extrato de Ginkgo biloba no cérebro de ratos expostos à RI. Para tanto foram utilizados 35 animais divididos em cinco grupos (n = 7): controle, irradiado, tratado apenas com o Gb, tratado com o Gb antes da irradiação (GBRI) e tratado com o Gb após da irradiação (RIGB). Os animais destes grupos passaram por um procedimento cirúrgico para implante dos eletrodos, visando o registro do eletrocorticograma. Os registros obtidos a partir do EMG 410C foram analisados pelos seguintes métodos matemáticos: Transformada de Fourier, Entropia Aproximada e Complexidade de Lempel-Ziv. Assim, foi observado que a RI interfere em todas as ondas cerebrais, aumentando a potência das ondas delta e beta e diminuindo as ondas teta e alfa. Por outro lado, os grupos RIGB e GBRI se assemelharam ao grupo controle, o que confere um caráter radioprotetor ao Gb. Do ponto de vista histológico, foi encontrado apoptose nas regiões CA1 e Giro Denteado apenas no grupo irradiado. Com base nos dados obtidos, pode-se concluir que efeito protetor do extrato do Ginkgo biloba pode ser uma escolha de terapia adjunta na redução da toxicidade induzida pela irradiação.

The nervous system is affected in several ways by exposure to ionizing radiation (IR), including cognitive and morphological damage. Oxidative stress, for example, is one of the effects of IR and is characterized by the imbalance between the production of reactive oxygen species and antioxidant defense mechanisms. Therefore, the search for radioprotectors becomes increasingly relevant to minimize these adverse effects. A prominent specimen in this scenario is Ginkgo biloba (Gb) because it is an antioxidant and has already been shown to be a neuroprotective. Therefore, the present work had as main objective to evaluate the possible radioprotective action of Ginkgo biloba extract in the brain of rats exposed to IR. For this purpose, 35 animals were used, divided into five groups (n = 7): control, irradiated, treated only with Gb, treated with Gb before irradiation (GBRI) and treated with Gb after irradiation (RIGB). The animals in these groups underwent a surgical procedure to implant the electrodes, aiming to register the electrocorticogram. The records obtained from the EMG 410C were analyzed by the following mathematical methods: Fourier Transform, Approximate Entropy and Lempel-Ziv Complexity. Thus, it was observed that IR interferes in all brain waves, increasing the power of the delta and beta waves and decreasing the theta and alpha waves. On the other hand, the RIGB and GBRI groups were similar to the control group, which gives Gb a radioprotective character. From the histological point of view, apoptosis was found in the CA1 and Dentate Gyrus regions only in the irradiated group. Based on the data obtained, it can be concluded that the protective effect of Ginkgo biloba extract can be a choice of adjunct therapy in reducing irradiation-induced toxicity.

Chicken Meat Submitted to Gamma Radiation and Packed with or without Oxygen

The objective of this study was to evaluate the effects on gamma radiation levels on the physical and microbiological characteristics of chicken breast meat. A completely randomized experimental design in a 4x2x3 factorial arrangement was adopted. Treatments consisted of four radiation concentrations (0, 2, 4, or 8kGy), two package sealing methods (with or without vacuum), and three storage times (01, 07, or 14 days), with ten replicates each, totaling 240 chicken breast fillets. Packaging and radiation had no influence (p>0.05) on chicken breast meat pH, water retention capacity, or presence of Salmonella spp. Breast fillets not submitted to radiation and vacuum packed presented higher water retention capacity (p 0.05) than those radiated at 4kGy and vacuum packed. Drip loss in fillets radiated at 8kGy and not vacuum packed was higher (p 0.05) than in non-radiated and non-vacuum packed fillets; however, both were not different from the other treatments. Coliform presence increased with storage time in non-radiated samples; however, when these were vacuum-packed, their development was slower. The results of the present experiment suggest that the use of a low radiation dose (2kGy), combined with vacuum packing, may minimize the harmful effects of storage on chicken breast fillets.(AU)

Chicken Meat Submitted to Gamma Radiation and Packed with or without Oxygen

The objective of this study was to evaluate the effects on gamma radiation levels on the physical and microbiological characteristics of chicken breast meat. A completely randomized experimental design in a 4x2x3 factorial arrangement was adopted. Treatments consisted of four radiation concentrations (0, 2, 4, or 8kGy), two package sealing methods (with or without vacuum), and three storage times (01, 07, or 14 days), with ten replicates each, totaling 240 chicken breast fillets. Packaging and radiation had no influence (p>0.05) on chicken breast meat pH, water retention capacity, or presence of Salmonella spp. Breast fillets not submitted to radiation and vacuum packed presented higher water retention capacity (p 0.05) than those radiated at 4kGy and vacuum packed. Drip loss in fillets radiated at 8kGy and not vacuum packed was higher (p 0.05) than in non-radiated and non-vacuum packed fillets; however, both were not different from the other treatments. Coliform presence increased with storage time in non-radiated samples; however, when these were vacuum-packed, their development was slower. The results of the present experiment suggest that the use of a low radiation dose (2kGy), combined with vacuum packing, may minimize the harmful effects of storage on chicken breast fillets.

EFEITO DO ÔMEGA-3 SOBRE PADRÕES ELETROCORTICOGRÁFICOS DE RATOS WISTAR ADULTOS EXPOSTOS À RADIAÇÃO IONIZANTE

Os tratamentos oncológicos, como a radioterapia, produzem profundo impacto nas funções fisiológicas do organismo, causando efeitos diretos e indiretos nas estruturas vivas, podendo afetar o metabolismo de proteínas, lipídios e carboidratos. Os lipídeos são as principais formas de reserva energética na maioria dos organismos e desempenham uma variedade de funções celulares. Dentre esses, os ácidos graxos poliinsaturados da série ômega-3 se destacam por apresentarem efeitos benéficos à saúde humana. Em vista disso, buscou-se verificar o efeito da suplementação com ômega-3 na atividade cerebral em ratos Wistar que foram expostos a radiação ionizante numa dose de 18 Gy na região de cabeça e pescoço, a mesma utilizada em tratamentos radioterápicos. Foram utilizados 16 Rattus norvegicus divididos em 2 grupos experimentais, um grupo de animais suplementados com óleo de peixe (GT) (1ml/ VO/ dia/100g PV) (n = 8), que é rico em ômega-3, e um outro grupo de animais que recebeu uma solução de Na Cl 0,9% (GNT) (1ml/ VO/ dia/ 100g PV) (n = 8), ambos avaliados 24 horas antes da irradiação e 24 horas e 1 semana depois da irradiação. Na 17º semana pós-natal os animais foram submetidos ao procedimento cirúrgico para implante de eletrodos. No 15º dia pós-operatório os animais foram irradiados. O registro do ECoG dos animais foi realizado durante exploração espacial 24 horas pré-exposição, 24 horas pós-exposição e 1 semana pós-exposição durante 30 minutos para cada registro. Os sinais do ECoG foram amplificados, registrados e segmentados. Na análise da série temporal do sinal do ECoG foram utilizados o espectro de potência (EP) e a análise de flutuação Destendenciada (DFA). Esses métodos matemáticos foram sensíveis em detectar alterações no ECoG, tanto em decorrência do efeito do ômega-3 como da radiação. Nos animais tratados com ômega-3, a técnica do EP mostrou que houve uma redução significativa (p=0,0184) na potência do ritmo beta, enquanto, a técnica do DFA quando aplicada às diferentes faixas de frequência (teta, delta, alfa e beta) revelou uma diferença estatisticamente significativa unicamente para a onda teta (p= 0,0003). Na avaliação do efeito da radiação através do EP foi observado que houve um aumento na potência do ritmo teta do ECoG (p= 0,0453), somente quando avaliados uma semana após a irradiação. Quanto ao efeito da radiação em animais tratados com ômega-3 foi observado que houve um aumento na potência do ritmo teta do ECoG (p= 0,0220), somente quando avaliados uma semana após a irradiação (Efeito tardio). A técnica do DFA aplicada às diferentes faixas de frequência também mostrou diferença estatisticamente significativa para a onda teta (p= 0,0053) no grupo com ômega-3 e não irradiado em relação ao grupo com ômega-3 e irradiado, avaliados uma semana após a exposição a radiação ionizante. Diferença também encontrada na onda Teta para a avaliação realizada entre o grupo sem ômega-3 e com ômega-3, após 24 horas (0,0055) e 1 semana (p=0,0252) da irradiação. Quanto ao ritmo beta, na avaliação realizada com 1 semana após a irradiação, o DFA das diferentes faixas de frequência, mostrou alteração (p=0,0067) entre o grupo sem ômega-3 e com ômega-3.

Cancer treatments, such as radiotherapy, have a profound impact on the body's physiology, causing direct and indirect effects on living structures, which can affect the metabolism of proteins, lipids and carbohydrates. Lipids are the main forms of energy reserve in most organisms and they perform a variety of cellular functions. Among these, the polyunsaturated fatty acids of the omega-3 series stand out for having beneficial effects on human health. In view of this, this work sought to verify the effect over the brain activity of supplementation with omega-3 in Wistar rats that were exposed to ionizing radiation at a dose of 18 Gy on head and neck regions, the same dose used in radiotherapy treatments. 16 Rattus norvegicus were used, divided into 2 experimental groups, a group of animals supplemented with fish oil (GT) (1ml / OW / day / 100g LW) (n = 8), which is rich in omega-3, and another group who received a solution of 0.9% NaCl (GNT) (1ml / OW / day / 100g LW) (n = 8), both group were evaluated 24 hours before irradiation, in 24 hours and 1 week after irradiation. At the 17th postnatal week, the animals were submitted to a surgical procedure to implant electrodes. On the 15th postoperative day, the animals were irradiated. The ECoG recording of the animals was performed during space exploration of 24 hours pre-exposure, 24 hours post-exposure and 1 week post-exposure during 30 minutes. The ECoG signals were amplified, recorded and segmented. In the analysis of the time series of the ECoG signal, the power spectrum (PS) and the detrended fluctuation analysis (DFA) were used. These mathematical methods were sensitive in detecting changes in ECoG, due to the effect of omega-3 and radiation. In animals treated with omega-3, the PS technique showed that there was a significant decrease (p = 0.0184) in the beta rhythm power. While the DFA technique was applied to the different frequency ranges (theta, delta, alpha and beta) it revealed a statistically significant difference only for the theta wave (p = 0.0003). In the evaluation of the radiation effect through the PS, it was observed an increase in the power of the theta rhythm of the ECoG (p = 0.0453), only when they were evaluated one week after the irradiation (Late effect). Regarding the effect of radiation in animals treated with omega-3, it was observed that there was an increase in the power of the theta rhythm of the ECoG (p = 0.0220), only when they were evaluated one week after irradiation. The DFA technique applied to the different frequency bands also showed a statistically significant difference for the theta wave (p = 0.0053) in the group with omega-3 and non-irradiated in relation to the group with omega-3 and irradiated, groups evaluated one week after exposure to ionizing radiation. Difference also was found in the evaluation carried out between the group without omega-3 and with omega-3, after 24 hours (0.0055) and 1 week (p = 0.0252) of the irradiation. As for the beta rhythm, in the evaluation performed 1 week after irradiation, the DFA of the different frequency bands showed an alteration (p = 0.0067) between the group without and with omega-3.

Integridade de DNA e morfologia espermática de ratos submetidosa campos eletromagnéticos de baixa frequência durante diferentesperíodos do desenvolvimento / DNA integrity and sperm morphology of Wistar rats exposed to low frequency electromagnetic fields during different periods of development

A exposição da sociedade a Campos Eletromagnéticos (CEM) vemaumentando vertiginosamente em virtude da ampla expansão tecnológica observada nosúltimos anos. Tanto a geração, como a distribuição e a utilização de energia elétrica podemgerar Campos Eletromagnéticos de baixa freqüência (50 e 60 Hz). Pesquisas vêmdemonstrando que a exposição a estes CEM podem proporcionar alterações fisiológicassignificativas, apesar disto, ainda não estão totalmente esclarecidos a extensão destes efeitos,nem os mecanismos de ação que envolve a interação dos CEM com os organismosbiológicos. O presente trabalho teve como principal objetivo verificar os efeitos dos CEM(60 Hz e 1 mT) sobre a integridade de DNA e morfologia espermática de ratos sexualmentemaduros, que foram expostos ao CEM durante diferentes períodos do seudesenvolvimento. Os resultados obtidos neste trabalho não encontraram indícios dealterações no DNA dos espermatozóides, porém, foram observadas alterações significativasna morfologia dos espermatozoides após a exposição ao CEM. Estas alterações namorfologia espermática podem reduzir o potencial reprodutivo. Portanto, devemosconsiderar o CEM como um potencial risco a saúde pública, recomendando-se a realizaçãode mais pesquisas buscando estabelecer níveis seguros de exposição aos CEM.(AU)

Thesocietys exposure to electromagnetic fields (EMF) has been growing considerable due tothe great technological expansion observed in the last few years. Generation as well asdistribution and use of electric energy can generate low frequency electromagnetic fields(50 and 60 Hz). Issues have been demonstrating that EMF exposure could provokesignificantly physiological changes, however, the extension of EMF effects werent totallyclarified. The major objective of this issue was to evaluate the EMF (60 Hz and 1 mT)effects on DNA integrity and sperm morphology in Wistar rats with mature sexuality thatwere exposed during different stages of testicular development. According to our results,EMF did not change DNA integrity, but we could observe morphological changes in spermafter exposure to EMF. These changes in sperm morphology may reduce the reproductivepotential. Therefore, we should consider the EMF as a potential risk to public health,recommending the implementation of further research seeking to establish safe levels ofexposure to EMF.(AU)

Study of irradiated bothropstoxin-1 with60Co gamma rays: immune system behavior

Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.

Caracterização sensorial e análise bacteriológica do peixe-sapo (Lophius gastrophysus) refrigerado e irradiado / Sensorial characterization and bacteriological analysis of the peixe-sapo (Lophius gastrophysus) chilled and irradiated

As amostras de filé de peixe-sapo (Lophius gastrophysus) receberam doses de 3, 5, e 7kGy de radiação gama. A contagem de bactérias heterotróficas aeróbicas psicotróficas foi realizada em diferentes tempos de estocagem à temperatura de 0ºC, juntamente com a amostra controle. Também foi analisado o perfil sensorial de sabor e aroma, além da avaliação da preferência quanto à cor. Dentre as amostras irradiadas, a que obteve melhor qualidade, quanto aos atributos e às amplitudes de sabor e aroma, foi a amostra irradiada a 5kGy. As amostras controle, 3, e 5kGy não diferiram significativamente entre si, sendo consideradas como as mais preferidas quanto à cor, sugerindo uma aparência de maior frescor, quando comparadas com a amostra 7kGy. Sugere-se a dosagem de radiação gama de 5kGy como a mais eficiente na manutenção da qualidade bacteriológica e sensorial em filé de peixe-sapo refrigerado.(AU)

The samples of the fillets of peixe-sapo (Lophius gastrophysus) received 3, 5 and 7kGy gamma irradiation. The count of psicotrophic aerobic heterotrophic bacteria was accomplished in different times of store to the temperature of 0ºC, together with the sample control the sensory profile of the was analyzed. Also flavor and aroma besides the evaluation of the preference with relationship to color. Among the irradiated samples the on that obtained better quality, as attributes and flavor widths and aroma, it was the sample radiated to the 5kGy. The samples control, 3, and 5kGy didn't differ significantly each other being considered as the most favorite with relationship to the color, suggesting an appearance of larger coolness when compared with 7kGy sample. Dosage of radiation is suggested it gamma of the most efficient 5kGy as in the maintenance of the bacteriological and sensory quality in fillet of cooled peixe-sapo.(AU)

Peritoneal infection by Candida albicans: study of number and size of limphocytes and phagocitic activy of peritoneal machophages in mice

The main purpose of this investigation was to stdy some aspects of leucocytes (granulocytes and limphocytes) and the phagocitic activity of peritoneal macrophages. In this experimen, which took place at Escola Paulista de Medicina - Universidade Federal de São Paulo - Brazil, it was used twenty female C57BLACK mice. Half of them were submitted to radiation to obtain immunossupressed animals (Group A - irradiated mice). The other ten mice were not iiradiated (Group B - control). The animals were sorted in four subgroups A-2 and B-2, were infected with Candida albicans (ATCC 90029). The resultant data showed significant differences in the number of leucocytes (granulocytes and limphocytes), and in the medium size of limphocytes between irradiated and non irradiated mice. Related to peritoneal macrophages, it was observed that the number of macrophages was lower in irradiated mice and the phagocitic was decreased in the irradiated and infected animals.

Irradiação de resíduos fibrosos com feixes de elétrons: efeitos na composição química e digestibilidade

Samples of sugarcane bagasse, rice and cotton residues were irradiated with various doses (200, 400, 600, 800 and l000kGy) in an electron accelerator with or without anhydrous gaseous NH3 post-treatment, to evaluate the effects of irradiation on dry matter digestibility and on their chemical and physical properties. After irradiation, samples were dried and ground for chemical analysis. Dry matter digestibility was determined with the nylon bag technique. Structural analysis was performed using light and electron microscopy. Crude fiber and neutral detergent fiber significantly decreased (P 0.01) for irradiated samples. Phenolic contents increased with the applied dose indicating that lignin was decomposed. Dry matter digestibility increased with increasing dose. An increase of 24 digestibility units was observed for bagasse at highest dose. Based on microscopy, fragmentation of sugarcane bagasse was observed at 800-1000kGy and some celular alterations occurred at 200kGy for rice and cotton residues. lt was concluded that irradiation caused significant changes on chemical and physical properties and on digestibility of fibrous residues. Utilization of irradiated biomass for animal feed appears promising.

Amostras de bagaço de cana e resíduos de cultura de arroz e algodão foram irradiadas com feixes de elétron, em acelerador industrial tipo Dynamitron para verificar os efeitos da dose de irradiação na digestibilidade da matéria seca e na composição química e estrutural. Os tratamentos consistiram na aplicação de 200, 400, 600, 800 e l000kGy com ou sem aplicação de amônia gasosa para o bagaço de cana e 200kGy com e sem amônia para os resíduos de cultura. Após os tratamentos, o material foi seco e moído para a análise bromatológica completa. A digestibilidade in situ foi medida pela técnica envolvendo sacolas de náilon. As análises estruturais foram realizadas por microscopia óptica e eletrônica. A irradiação produziu uma redução nos conteúdos de fibra bruta e fibra detergente neutro (P 0.01). O teor de compostos fenólicos aumentou com a dose aplicada, sugerindo quebras na estrutura do complexo lignocelulósico. Verificou-se um aumento na digestibilidade com o incremento da dose. Para o bagaço de cana, as doses mais elevadas produziram um incremento de 24 unidades em digestibilidade em relação ao material não tratado; para os restos de cultura os aumentos foram menores. Pela análise estrutural, verificou-se que doses de 800 e l000kGy produziram fragmentação no bagaço de cana. Nas amostras referentes à cultura de arroz e algodão, observou-se alguma alteração celular e separação de fibras com 200kGy. Concluiu-se que a irradiação por elétrons levou a alterações significativas na composição química, estrutural e na digestibilidade de resíduos fibrosos. A utilização de biomassa irradiada como complemento na alimentação aos ruminantes parece ser promissora.

IRRADIAÇÃO DE RESÍDUOS FIBROSOS COM FEIXES DE ELÉTRONS: EFEITOS NA COMPOSIÇÃO QUÍMICA E DIGESTIBILIDADE

Samples of sugarcane bagasse, rice and cotton residues were irradiated with various doses (200, 400, 600, 800 and l000kGy) in an electron accelerator with or without anhydrous gaseous NH3 post-treatment, to evaluate the effects of irradiation on dry matter digestibility and on their chemical and physical properties. After irradiation, samples were dried and ground for chemical analysis. Dry matter digestibility was determined with the nylon bag technique. Structural analysis was performed using light and electron microscopy. Crude fiber and neutral detergent fiber significantly decreased (P 0.01) for irradiated samples. Phenolic contents increased with the applied dose indicating that lignin was decomposed. Dry matter digestibility increased with increasing dose. An increase of 24 digestibility units was observed for bagasse at highest dose. Based on microscopy, fragmentation of sugarcane bagasse was observed at 800-1000kGy and some celular alterations occurred at 200kGy for rice and cotton residues. lt was concluded that irradiation caused significant changes on chemical and physical properties and on digestibility of fibrous residues. Utilization of irradiated biomass for animal feed appears promising.

Amostras de bagaço de cana e resíduos de cultura de arroz e algodão foram irradiadas com feixes de elétron, em acelerador industrial tipo Dynamitron para verificar os efeitos da dose de irradiação na digestibilidade da matéria seca e na composição química e estrutural. Os tratamentos consistiram na aplicação de 200, 400, 600, 800 e l000kGy com ou sem aplicação de amônia gasosa para o bagaço de cana e 200kGy com e sem amônia para os resíduos de cultura. Após os tratamentos, o material foi seco e moído para a análise bromatológica completa. A digestibilidade in situ foi medida pela técnica envolvendo sacolas de náilon. As análises estruturais foram realizadas por microscopia óptica e eletrônica. A irradiação produziu uma redução nos conteúdos de fibra bruta e fibra detergente neutro (P 0.01). O teor de compostos fenólicos aumentou com a dose aplicada, sugerindo quebras na estrutura do complexo lignocelulósico. Verificou-se um aumento na digestibilidade com o incremento da dose. Para o bagaço de cana, as doses mais elevadas produziram um incremento de 24 unidades em digestibilidade em relação ao material não tratado; para os restos de cultura os aumentos foram menores. Pela análise estrutural, verificou-se que doses de 800 e l000kGy produziram fragmentação no bagaço de cana. Nas amostras referentes à cultura de arroz e algodão, observou-se alguma alteração celular e separação de fibras com 200kGy. Concluiu-se que a irradiação por elétrons levou a alterações significativas na composição química, estrutural e na digestibilidade de resíduos fibrosos. A utilização de biomassa irradiada como complemento na alimentação aos ruminantes parece ser promissora.

Study about the sensibility in vitro of different strains of Vibrio cholerae 01 exposed to 60 Co gamma radiation / Estudo da sensibilidade in vitro de diferentes cepas de Vibrio cholerae 01 à radiação gama de 60Co

The presence of some microorganisms in food, or the metabolites originated during their own multiplication, may bring several diseases to humans: intoxications and foodborne infections. Among the agents that may cause those diseases, we find Vibrio cholerae 01. In this experiment, the studies are focused on the radiosensibility in vitro of four strains of V. cholerae 01, exposed to different doses of ionizing radiation of 60Co. The results are compared with other data related to bacterial foodborne diseases, including water.

A presença de certos microrganismos nos alimentos ou de metabolitos originados durante sua multiplicação pode dar lugar a várias enfermidades no homem: as intoxicações e as infecções alimentares. Dentre os agentes causadores das Enfermidades Transmitidas por Alimentos encontra-se o Vibrio cholerae 01. Estudou-se no presente trabalho a radiossensibilidade in vitro de quatro cepas de V. cholerae 01, submetidas ao tratamento com diferentes doses de radiação ionizante de 60Co, e compararam-se os resultados obtidos com dados da literatura relacionados a problemas de veiculação alimentar de bactérias patogênicas, incluindo a água.

Eliminação ou inativação de fungos do gênero Aspergillus em amendoim (Arachis hypogea, L), e o aumento de sua vida de prateleira, quando tratado com radiação gama / Elimination or inactivation of the fungi genus Aspergillus in peanut (Arachis hypogea, L), and increased its shelf-life when treated with gamma radiation

A presente pesquisa, investigou a eficácia da aplicação da radiação gama para evitar o aparecimento de fungos patogênicos em amendoim (Arachis hypogea, L), conseqüentemente, conferindo ao produto uma melhor qualidade fitossanitária e maior vida de prateleira. Foram pesquisadas amostras processadas salgadas e in-natura. Depois de submetidas à radiação proveniente de uma fonte de césio-137, para absorverem doses de 0; 1,5; 2,0 e/ou 2,5 kGy, as amostras foram monitoradas sensorial e micologicamente e comparadas às testemunhas (não irradiadas). Análises sensoriais periódicas mostraram que o tratamento por irradiação com dose de 2,0 kGy não alterou perceptivelmente o sabor do amendoim in-natura, mas causou uma evidente alteração no sabor das amostras de amendoim processado.(...).(AU)

This work has studied the efficiency of gamma radiation to either delay or prevent the incidence of pathogenic fungi in peanut (Arachis hypogea, L), consequently rendering it a better sanitary quality and longer shelf-life. Samples of natural (non processed) and processed (salty) peanut grains were investigated. After being exposed to gamma radiation supplied by a cesium-137 source, in order to absorb doses of O; 1,5; 2,0 and/or 2,5 kGy, the peanut samples were monitored for changes in flavor and fungi growth and compared to the non-irradiated ones (witnesses). Periodic sensory analyses showed that the irradiation treatment with a 2,0 kGy dose did not produce any noticeablechange in flavor of natural peanut grains, but significantly altered the flavor of processed (salty) peanut. (...)(AU)

Efeito da radiação gama na sanitização da maçã Royal Gala minimamente processada / Effect of the radiation gamma in the sanitization of the Royal Gala apple minimally processed

O objetivo do presente trabalho foi verificar os efeitos da radiação gama na conservação pós-colheita da maçã Royal Gala minimamente processada, determinando a melhor dose para estender a sua vida útil, reduzindo a incidência de patógenos, durante seu armazenamento. Os frutos foram lavados em água, cortados manualmente em cubos de 2x2 cm, imersos em solução 35 de ácido ascórbico e acondicionados em bandejas de isopor envolvidas em filme plástico. A seguir foram irradiados na EMBRARAD nas doses T1 (testemunha), T2 (0,1kGy), T3 (0,2kGy), T4 (0,3kGy), T5(0,4kGy) e T6(0,5kGy), e armazenados a 5ºC com 85 por cento de umidade relativa. Aos 2, 4, 6, 8 e 10 dias de armazenamento foi avaliada a incidência de microrganismos mesófilos e psicotróficos, contagens microbiológicas dos grupos coliformes totais e fecais. Pelos resultados obtidos, pôde-se verificar, após 10 dias de armazenamento, que a irradiação mostrou ser um tratamento pós-colheita eficiente para a maçã minimamente processada, sendo que os frutos com a dose 0,5kGy, apresentaram menores quantidades de mesófilos,psicotróficos, bolores e leveduras, enquanto os frutos da testemunha apresentaram grande quantidade de mesófilos e psicotróficos. Logo, pode-se concluir que a irradiação na dose 0,5kGy foi efetiva no tratamento da maçã minimamente processada.(AU)

The objective of the present experiment was to verify the effects of the radiation gamma in the conservation postharvest of apple 'Royal Gala' minimally processed, determining the best dose to extend its shelf life, reducing the microorganism incidence, during its storage. The fruits were washed in water, cut manually in cubes of 2x2cm, immersed in solution of 3% of ascorbic acid and conditioned in isopor trays involved in plastic film. Afterthat, they were irradiated in the EMBRARAD company, with the doses: T1 (control), T2 (O,l kGy), T3 (O,2 kGy), T4 (0,3kGy), T5(0,4kGy) and T6 (O,5kGy), and stored under 5°e and 85% RM. To the 2, 4, 6, 8 and 10 days of storage it was evaluated the incidence of microorganisms mesophiles, psychrophils, mould, yeasts and coliforms. For the obtained results, it could be verified, after 10 days of storage, that the irradiation showed to be a treatment efficient postharvest for the apple minimally processed, and the fruits with the dose ofO,5kGy, presented smaller amounts of mesophiles, psychrophils, mould and yeasts, while the fruits contral presented great amount of mesophiles, psychrophils, mould and yeasts. Therefore, it can be concluded that the irradiation in the dose O,5kGy was effective in the treatment of the apple minimally processed. (AU)

Efeito da radiação gama na sanitização do tomate minimamente processado e acondicionado à vácuo / Effect of the radiation gamma in the tomatoe minimally processed and conditioned to the vacuum

O objetivo do presente trabalho foi verificar os efeitos da radiação gama na conservação pós-colheita de tomate minimamente processado, determinando a melhor dose para estender a sua vida útil, e reduzindo a incidência de patógenos, durante seu armazenamento. Os frutos foram lavados em água, cortados manualmente em cubos de 2 x 2 cm e acondicionados em embalagens plásticas à vácuo. A seguir foram irradiados na EMBRARAD nas doses T1 (testemunha), T2 (0,1kGy), T3 (0,2kGy), T4 (0,3kGy), T5 (0,4kGy) e T6 (0,5kGy), e armazenados a 5ºC com 85 por cento de umidade relativa. Aos 2, 6 e 10 dias de armazenamento foi avaliada a incidência de microrganismos mesófilos e psicrotróficos, contagem de bolores, leveduras e contagens de microbiológicas dos grupos coliformes totais e fecais. Pelos resultados obtidos, pôde-se verificar, após 10 dias de armazenamento, que a irradiação mostrou ser um tratamento pós-colheita eficiente para o tomate minimamente processado, sendo que os frutos com as doses de 0,4 e 0,5kGy, apresentaram menores quantidades de mesófilos, psicrotróficos, bolores e leveduras, enquanto os frutos da testemunha apresentaram grande quantidade de mesófilos e psicrotróficos, bolores e leveduras, sendo considerados impróprios para o consumo no 6º dia de armazenamento. Logo, pode-se concluir que a irradiação nas doses de 0,4 e 0,5kGy foram efetivas no tratamento do tomate minimamente processado.(AU)

The objective of the present experiment was to verify the effects of the radiation in the conservation postharvest oftomato minimally processed, determining the best dose to extend its useful life, reducing the microorganism incidence, during its storage. The fruits were washed in water, cut manually in cubes of 2x2 cm and conditioned in plastic bag under vacuum. After that, they were irradiated in the EMBRARAD company, with the doses: T1 (control), T2 (O,lkGy), T3 (O,2kGy), T4 (O,3kGy), T5(0,4kGy) and T6 (O,5kGy), and stored under 5°e and 85% RM. To the 2, 6 and 10 days of storage it was evaluated the incidence of microorganisms mesophiles, psychrophils, mould, yeasts and coliforms. For the obtained results, it could be verified, after 10 days of storage, that the irradiation showed to be a treatment efficient postharvest for the tomato minimally processed, and the fruits with the doses of 0,4 and 0,5kGy, presented smaller amounts of mesophiles, psychrophils, mould and yeasts, while the fruits control presented great amount of mesophiles, psychrophils, mould and yeasts, being considered inappropriate for the consumption in the 6th day of storage. Therefore, it can be concluded that the irradiation in the doses ofO,4 and 0,5kGy was effective in the treatment of the tomato minimally processed. (AU)