Evaluation of genetic integrity in seeds of rice (Oryza sativa L.) and common bean (Phaseolus vulgaris L.) stored in gene banks

Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Animal, 2018.A manutenção da viabilidade de recursos genéticos vegetais em bancos de germoplasma é fundamental para uso dessas amostras (acessos) armazenadas em longo prazo dependendo, em parte, da manutenção da integridade genética. Metodologias para avaliar a integridade genética tem potencial para fornecer informações que auxiliariam no processo de monitoramento das coleções de germoplasma. O monitoramento das coleções é realizado pelo teste de germinação que, apesar de informativo e de baixo custo, não consegue detectar estágios iniciais de deterioração. Este estudo teve como objetivo avaliar a integridade genética em sementes de Oryza sativa L. (arroz) e Phaseolus vulgaris L. (feijão) envelhecidas artificial e naturalmente. Inicialmente, sementes de arroz e feijão foram expostas a um agente mutagênico, metanossulfonato de metila (MMS), para viabilizar a realização dos testes citogenéticos e cometa. Verificou-se que o MMS induziu efeitos citotóxicos, mutagênicos e/ou genotóxicos em acessos de arroz e feijão, contribuindo para a padronização de metodologias para avaliar citotoxicidade, mutagenicidade e genotoxicidade nestas espécies. A partir disto, foram analisados os efeitos do envelhecimento acelerado sobre a integridade genética em sementes de arroz e feijão. À medida que houve o aumento do período de envelhecimento, foi observada diminuição na germinação, vigor e índice mitótico, bem como o aumento da frequência de anomalias cromossômicas e quebras do DNA em ambas as espécies avaliadas. Estes resultados evidenciam o potencial uso dos testes citogenéticos e cometa em programas de conservação de sementes, pois eles permitem auxiliar na decisão de quais sementes podem ser armazenadas por períodos prolongados sem comprometer a sua integridade genética e, consequentemente, sua viabilidade e vigor. Por fim, foram realizadas análise da integridade genética e da eficácia do sistema de reparo de acessos de arroz e de feijão armazenados em longo prazo em bancos de germoplasma (-20°C). Observou-se que não houve aumento ou decréscimo significativo do índice mitótico e/ou anomalias cromossômicas, e houve similaridade entre os resultados dos testes de qualidade fisiológica e do teste cometa, ou seja, os lotes das duas espécies com sementes menos viáveis e/ou vigorosas apresentaram mais danos ao DNA e menor capacidade de reparo. Esse é o primeiro estudo sobre integridade genética e eficácia do sistema de reparo de germoplasma de semente conservado em longo prazo indicando que o teste cometa pode ser utilizado para esta finalidade. Adicionalmente, estas técnicas pode permitir o monitoramento de diferentes espécies, principalmente em acessos com pequena quantidade de sementes armazenadas (abaixo de 1.500), pois a quantidade de material utilizada (sementes e DNA) é baixa (10 sementes).Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) e Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ).Maintaining the viability of plant genetic resources in germplasm banks is fundamental for the use of these samples (accessions) under long-term storage, and this depends partly on maintaining their genetic integrity. Methodologies to evaluate genetic integrity have the potential to supply information that would help in the process of monitoring germplasm collections. The monitoring of collections is carried out by the germination test, which is informative and inexpensive, but does not manage to detect the initial stages of deterioration. This study had the objective of evaluating genetic integrity in seeds of Oryza sativa L. (rice) and Phaseolus vulgaris L. (common bean), aged artificially and naturally. Initially, rice and bean seeds were exposed to a mutagenic agent, methyl methane sulfonate (MMS), to make cytogenetic and comet tests viable. It was verified that MMS induced cytotoxic, mutagenic and/or genotoxic effects in rice and bean accessions, contributing to the standardization of methodologies to evaluate the cytotoxicity, mutagenicity and genotoxicity of these species. Leading on from this, the effects of accelerated aging on genomic stability were analyzed in rice and bean seeds. As the aging period increased, a reduction was observed in the germination, vigor and mitotic index, as well as an increase in the frequency of chromosomal aberrations and DNA breaks in both the evaluated species. These results show the potential use of cytogenetic and comet tests in seed conservation programs, because they aid in the decision about which seeds can be stored for prolonged periods without compromising their genetic integrity and, consequently, their viability and vigor. Finally, analysis was made regarding the genetic integrity and the effectiveness of the repair system of rice and bean accessions that were stored long-term in germplasm banks (-20 °C). It was observed that no significant increase or decrease was observed in the mitotic index and/or chromosomal aberrations, and there was a similarity between the results from the physiological quality tests and from the comet test; in other words, the lots of the two species with less viable and/or vigorous seeds presented less damage to the DNA and a lower repair capacity. This is the first study on genetic integrity and the effectiveness of the repair system of seed germplasm in long-term conservation, indicating that the comet test can be used for this purpose. Additionally, these techniques may allow monitoring of different species, especially in accessions with a small quantity of stored seeds (fewer than 1500), because the quantity of material used (seeds and DNA) is low (10 seeds)

Evaluation of Toxic, Cytotoxic, Mutagenic, and Antimutagenic Activities of Natural and Technical Cashew Nut Shell Liquids Using the Allium cepa and Artemia salina Bioassays

The cashew nut releases a substance that is known as cashew nut shell liquid (CNSL). There are both natural (iCNSL) and technical (tCNSL) cashew nut shell liquids. This study used an Artemia salina bioassay to evaluate the toxic effects of iCNSL and tCNSL cashew nut shell liquids. It also evaluated the toxicity, cytotoxicity, and mutagenicity of CNSL and its effects on the damage induced by copper sulfate (CuSO4·5H2O) on the meristems’ root of Allium cepa. Effects of the damage induced by CuSO4·5H2O were evaluated before (pre-), during (co-), and after (post-) treatments. The iCNSL contained 94.5% anacardic acid, and the tCNSL contained 91.3% cardanol. The liquids were toxic to A. salina. Toxicity, cytotoxicity, and mutagenicity were observed with iCNSL compared with the negative control. Similarly, iCNSL failed to inhibit the toxicity and cytotoxicity of CuSO4·5H2O. The tCNSL was not toxic, cytotoxic, or mutagenic in any of the concentrations. However, the lowest iCNSL concentrations and all of the tCNSL concentrations had preventive, antimutagenic, and reparative effects on micronuclei and on chromosomal aberrations in the A. cepa. Therefore, protective, modulating, and reparative effects may be observed in the A. cepa, depending on the concentration and type of CNSL used

Irrigation Strategies with Controlled Water Deficit in Two Production Cycles of Cotton

Water scarcity is one of the main abiotic factors that limit agricultural production. In this sense, the identification of genotypes tolerant to water deficit associated with irrigation management strategies is extremely important. In this context, the objective of this study was to evaluate the morphology, production, water consumption, and water use efficiency of colored fiber cotton genotypes submitted to irrigation strategies with a water deficit in the phenological phases. Two experiments were conducted in succession. In the first experiment, a randomized block design was used in a 3 × 7 factorial scheme, corresponding to three colored cotton genotypes (BRS Rubi, BRS Jade, and BRS Safira) in seven irrigation management strategies with 40% of the real evapotranspiration (ETr) varying the phenological stages. In the second experiment, the same design was used in a 3 × 10 factorial arrangement (genotypes × irrigation management strategies). The water deficit in the vegetative phase can be used in the first year of cotton cultivation. Among the genotypes, ‘BRS Jade’ is the most tolerant to water deficit in terms of phytomass accumulation and fiber production

Gastroprotective and antifungal evaluation of spray-dried extract and effervescent pre-formulation from <i>Croton blanchetianus</i> Baill leaves

Aiming the medicinal potential of Croton blanchetianus leaves, the spray-drier extract (SDE) and the effervescent pre-formulation (EGCb) were evaluated for their acute oral toxicity, gastroprotective and antifungal effects. The phytochemical profile by high-performance liquid chromatography, total flavonoid content and total polyphenol content were performed. For the development of the effervescent pre-formulation (EGCb), the wet granulation technique was used, and its characterization and phytochemical profile were performed. Swiss mice were used for toxicity evaluation and gastroprotective activity against ethanol-induced ulcers. Antifungal activity was done against Candida spp. strains, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). The animals showed no toxic effects when the 2000 mg/kg dose of SDE was orally administered. The SDE promoted the gastroprotective effect in all doses, as well, as the effervescent pre-formulation at 200 mg/kg. The antifungal activity achieved MIC and MFC of 1000 μg/mL for SDE and EGCb, against C. albicans and C. glabrata, and a MIC of 500 μg/mL and MFC of 1000 μg/mL of SDE and 500 μg/mL of EGCb for the C. auris strain. Given the above, this study showed that the secondary metabolites present in the leaves of C. blanchetianus, confirmed its therapeutic potential, promoting the search for new knowledge and options for future pharmaceutical formulations.</p

Processamento da casca de mandioca na alimentação de ovinos: desempenho, características de carcaça, morfologia ruminal e eficiência econômica Processing of cassava peel in sheep feeding: performance, carcass characteristics, ruminal morphology and economic efficiency

Avaliou-se o efeito de diferentes formas de processamento da casca de mandioca na alimentação sobre o desempenho e as características de carcaça, a morfologia ruminal e a viabilidade técnico-econômica da criação de ovinos. Foram utilizados 20 ovinos machos da raça Santa Inês, desmamados, com peso inicial de 19,02±0,21 kg e 90 dias de vida. O delineamento experimental foi inteiramente casualizado com cinco repetições por dieta. Durante o período experimental de 84 dias, incluindo 14 dias de adaptação, os animais foram mantidos em sistema de semiconfinamento em pastagem de Brachiaria decumbens. Foram avaliadas quatro formas de processamento da casca de mandioca: desidratada triturada em peneira de 12 ou de 5 mm; úmida triturada e ensilada; e úmida triturada e hidrolisada com 0,5% de cal virgem (óxido de cálcio - CaO). O peso médio ao abate foi 30,72±1,46 kg. Não houve influência do tipo de processamento da casca sobre as características de desempenho analisadas, as características quantitativas de carcaça e a morfologia ruminal, sendo influenciado somente o rendimento de paleta. A casca de mandioca hidrolisada foi a que promoveu melhor eficiência econômica. Os tipos de processamento da casca de mandioca não alteram o desempenho, as características de carcaça, os rendimentos de corte e a morfologia ruminal dos ovinos Santa Inês.<br>The objective of this trial was to evaluate the effect of different forms of processing of cassava peel in sheep feeding on performance traits, carcass, morphology and rumen and economic technical feasibility. Twenty non-castrated male Santa Ines lambs of 19.02±0.21 kg of initial body weight and 90 days of age at the beginning of the study were used in this trial. The design was completely randomized design with five replications per treatment. During the experimental period of 84 days, including 14 days of adaptation, animals were kept in semi-confinement on Brachiaria decumbens. Four forms of cassava peel processing were evaluated: dried cassava peel ground through 12-mm sieve; dried cassava peel ground through 5-mm sieve; ground and ensiled cassava peel, and wet, ground hydrolyzed with 0.5% lime (calcium oxide - CaO). The average weight at slaughter was 30.72±1.46 kg. There was no influence of the type of processing on the performance variables analyzed, quantitative carcass characteristics or ruminal morphology; only the values of width and leg yield palette were influenced. Hydrolyzed cassava peel showed the best economic efficiency between treatments. The different methods of processing cassava peel do not affect performance, carcass characteristics, yield cuts or rumen morphology of Santa Ines sheep