Detection and quantification of Roundup Ready® soybean residues in sausage samples by conventional and real-time PCR

The increasing presence of products derived from genetically modified (GM) plants in human and animal diets has led to the development of detection methods to distinguish biotechnology-derived foods from conventional ones. The conventional and real-time PCR have been used, respectively, to detect and quantify GM residues in highly processed foods. DNA extraction is a critical step during the analysis process. Some factors such as DNA degradation, matrix effects, and the presence of PCR inhibitors imply that a detection or quantification limit, established for a given method, is restricted to a matrix used during validation and cannot be projected to any other matrix outside the scope of the method. In Brazil, sausage samples were the main class of processed products in which Roundup Ready® (RR) soybean residues were detected. Thus, the validation of methodologies for the detection and quantification of those residues is absolutely necessary. Sausage samples were submitted to two different methods of DNA extraction: modified Wizard and the CTAB method. The yield and quality were compared for both methods. DNA samples were analyzed by conventional and real-time PCR for the detection and quantification of Roundup Ready® soybean in the samples. At least 200 ng of total sausage DNA was necessary for a reliable quantification. Reactions containing DNA amounts below this value led to large variations on the expected GM percentage value. In conventional PCR, the detection limit varied from 1.0 to 500 ng, depending on the GM soybean content in the sample. The precision, performance, and linearity were relatively high indicating that the method used for analysis was satisfactory.

Consumer preferences of genetically modified foods of vegetal and animal origin in Chile

Given the debate generated by Genetically Modified (GM) foods in developed and developing countries, the aim was to evaluate the importance of determining factors in the preference of consumers in Temuco and Talca in central-southern Chile for GM foods using conjoint analysis and to determine the existence of different market segments using a survey of 800 people. Using conjoint analysis, it was established that, in general, genetic modification was a more important factor than either brand or price in the consumer's decision to purchase either food. Cluster analysis identified three segments: the largest (51.4%) assigned greatest importance to brand and preferred genetically modified milk and tomato sauce; the second group (41.0%) gave greatest importance to the existence of genetic manipulation and preferred non-genetically modified foods; the smallest segment (7.6%) mainly valued price and preferred milk and tomato sauce with no genetic manipulation. The three segments rejected the store brand and preferred to pay less for both foods. The results are discussed based on studies conducted in developed and developing countries.

Investigation of cytotoxic and mutagenic effects of Malpighia glabra L. (barbados cherry) fruit pulp and vitamin C on plant and animal test systems

Fruits are important sources of nutrients in human diet, and Barbados Cherry (Malpighia glabra L.) is of particular interest due to its high content of antioxidants. Diets rich in fruits and vegetables protect individuals against diseases and cancer, but excessive intake of vitamins may act as pro-oxidant and generate changes in DNA. To evaluate the effect of different in natura (BAN) and frozen (BAF) Barbados Cherry pulp concentrations and synthetic vitamin C in liquid form (VC) on the chromosome level and the cell cycle division, root meristeme cells of Allium cepa L. and bone marrow cells of Wistar rats Rattus norvegicus, were used as test system. In Allium cepa L., BAN, at the highest concentration (0.4 mg.mL-1) and BAF, at the lowest concentration (0.2 mg.mL-1), inhibited cell division, and there was recovery of cell division after the recovery period in water only for BAN. In the Wistar rats, all treatments with Barbados Cherry, either acute or subchronic, were not cytotoxic or mutagenic; only the highest concentration of VC increased significantly the rate of chromosomal abnormalities. The data obtained are important to reinforce the use of Barbados Cherry fruit in the diet.

Acceptance of a food of animal origin obtained through genetic modification and cloning in South America: a comparative study among university students and working adults

AbstractWith the aim of comparing the acceptance of milk obtained from cloned, genetically modified (GM) and conventionally bred cows among working adults and university students, and identifying and characterizing typologies among both subsamples in terms of their preferences, a survey was applied to 400 people in southern Chile, distributed using a simple allocation among the subsamples. Using a conjoint analysis, it was found that consumers preferred milk from a conventional cow. Using a cluster analysis, in both subsamples two segments sensitive to production technology were identified. Rejection of cloning was greatest among university students, whereas a higher proportion of working adults rejected GM. The segments differed in terms of area of residence, knowledge about GM, and milk consumption habits. Contrary to what was expected, no differences were found according to education, gender or degree of satisfaction with food-related life.

Indução de resposta inflamatória sistêmica e espessamento de artérias subepicárdicas em um modelo animal de uremia

A disfunção renal é um fator de risco para doença cardiovascular (DCV). Estudos experimentais controlados que possam analisar o impacto da disfunção renal no sistema cardiovascular, isolando esses fatores relacionados à uremia dos fatores de risco tradicionais, que são altamente prevalentes na população com doença renal crônica (DRC), ainda são escassos. OBJETIVO: Analisar o impacto cardiovascular em ratos com disfunção renal, analisando biomarcadores de risco cardiovascular e a histologia das artérias subepicárdicas desses animais. MÉTODOS: Estudo experimental envolvendo trinta ratos machos Wistar, divididos em dois grupos. Um grupo foi submetido à ablação renal e o outro grupo SHAM (grupo controle) à manipulação do pedículo renal. Ambos os grupos foram acompanhados por oito semanas, período em que foram feitas dosagens de ureia, fósforo e do fator de necrose tumoral alfa (TNF-α). Lâminas obtidas de cortes do miocárdio foram confeccionadas para análise das características das arteríolas subepicárdicas. RESULTADOS: O grupo DRC apresentou níveis elevados de uréia e fósforo em relação ao grupo SHAM. Já os níveis de TNF-α, em todas as análises, foram indetectáveis nos animais do grupo SHAM, em contraste com o grupo DRC, onde se observaram elevados níveis de TNF-α (p < 0,05). A espessura da camada média dos vasos subepicárdicos do grupo DRC foi significativamente maior do que em relação ao grupo SHAM (p = 0,011). CONCLUSÃO: A indução de disfunção renal determinou alterações em biomarcadores de risco cardiovascular e um aumento na espessura dos vasos subepicárdicos estudados em comparação aos animais com função renal normal.