989 resultados para ecological process


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The microbial spoilage of meat and seafood products with short shelf lives is responsible for a significant amount of food waste. Food spoilage is a very heterogeneous process, involving the growth of various, poorly characterized bacterial communities. In this study, we conducted 16S ribosomal RNA gene pyrosequencing on 160 samples of fresh and spoiled foods to comparatively explore the bacterial communities associated with four meat products and four seafood products that are among the most consumed food items in Europe. We show that fresh products are contaminated in part by a microbiota similar to that found on the skin and in the gut of animals. However, this animal-derived microbiota was less prevalent and less abundant than a core microbiota, psychrotrophic in nature, mainly originated from the environment (water reservoirs). We clearly show that this core community found on meat and seafood products is the main reservoir of spoilage bacteria. We also show that storage conditions exert strong selective pressure on the initial microbiota: alpha diversity in fresh samples was 189 +/- 58 operational taxonomic units (OTUs) but dropped to 27 +/- 12 OTUs in spoiled samples. The OTU assemblage associated with spoilage was shaped by low storage temperatures, packaging and the nutritional value of the food matrix itself. These factors presumably act in tandem without any hierarchical pattern. Most notably, we were also able to identify putative new clades of dominant, previously undescribed bacteria occurring on spoiled seafood, a finding that emphasizes the importance of using culture-independent methods when studying food microbiota.

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This paper presents a harmonised framework of sediment quality assessment and dredging material characterisation for estuaries and port zones of North and South Atlantic. This framework, based on the weight-of-evidence approach, provides a structure and a process for conducting sediment/dredging material assessment that leads to a decision. The main structure consists of step 1 (examination of available data); step 2 (chemical characterisation and toxicity assessment); decision 1 (any chemical level higher than reference values? are sediments toxic?); step 3 (assessment of benthic community structure); step 4 (integration of the results); decision 2 (are sediments toxic or benthic community impaired?); step 5 (construction of the decision matrix) and decision 3 (is there environmental risk?). The sequence of assessments may be interrupted when the information obtained is judged to be sufficient for a correct characterisation of the risk posed by the sediments/dredging material. This framework brought novel features compared to other sediment/dredging material risk assessment frameworks: data integration through multivariate analysis allows the identification of which samples are toxic and/or related to impaired benthic communities; it also discriminates the chemicals responsible for negative biological effects; and the framework dispenses the use of a reference area. We demonstrated the successful application of this framework in different port and estuarine zones of the North (Gulf of Cadiz) and South Atlantic (Santos and Paranagua Estuarine Systems).

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We analyzed six apiaries in several natural environments with a Mediterranean ecosystem in Madrid, central Spain, in order to understand how landscape and management characteristics may influence apiary health and bee production in the long term. We focused on five criteria (habitat quality, landscape heterogeneity, climate, management and health), as well as 30 subcriteria, and we used the analytic hierarchy process (AHP) to rank them according to relevance. Habitat quality proved to have the highest relevance, followed by beehive management. Within habitat quality, the following subcriteria proved to be most relevant: orographic diversity, elevation range and important plant species located 1.5 km from the apiary. The most important subcriteria under beehive management were honey production, movement of the apiary to a location with a higher altitude and wax renewal. Temperature was the most important subcriterion under climate, while pathogen and Varroa loads were the most significant under health. Two of the six apiaries showed the best values in the AHP analysis and showed annual honey production of 70 and 28 kg/colony. This high productivity was due primarily to high elevation range and high orographic diversity, which favored high habitat quality. In addition, one of these apiaries showed the best value for beehive management, while the other showed the best value for health, reflected in the low pathogen load and low average number of viruses. These results highlight the importance of environmental factors and good sanitary practices to maximize apiary health and honey productivity.

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The application of molecular methods offers an alternative faster than traditional methods based on morphology It is nearly impossible to process all the samples in short period using traditional methods, and the deterioration of marine sediments rapidly occurs The dT-RFLP (directed Terminal-Restriction Fragment Length Polymorphism) allows a rapid assessment of biodiversity changes of nematodes assemblages The use of a not suitable fixing, storage time and DNA extraction could be a limitation in molecular analysis like dT-RFLP and real time PCR.Objetives: the best fixative •the level of DNA degradation over the time •the best DNA extraction method for marine nematodes and suitable for dT-RFLP analysis

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This report shows some initial results about the research project entitled GlobalOrg, on a Brazilian case study, investigating the sustainability of tropical fruit organic farming in a global food chains perspective. It was performed an analysis about the production strategies of certified units of a familiar smalholders cooperative from Itápolis-SP-Brazil. In this analysis it was verified the application of sustainability principles recommended by the ecological based agriculture, focused on the agrobiodiversity, material recycling and the social-economic aspects from the agroecology conversion process. The research occurs through the complementarities provided by a combination of sociological and agronomic research methods, it means, qualitative interviews and questionnaire application with semi-structured questions. What was concluded is that the establishment of an economic relationship between the cooperative and a fair-trade international entity stimulates an interesting growing in the production diversity and also stimulates the application of different principles of ecological based agriculture. It indicates an important balance between the sustainability dimensions and demonstrates a visible attitude change in the natural resource exploration in this region.

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