342 research outputs found

    Diachronic analysis of farmers' strategies within a protected area of central Italy

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    The farm can be considered as the decision unit in the agricultural land management, therefore it is the most suitable scale to analyse the farmers’ strategies of production. In this paper we describe the results of a comparison between two enquiries carried out in 1992-93 and 2009-10 on more than 30 farms, corresponding to about 1500 ha of utilised agricultural area (UAA), within the boundaries of the San Rossore, Migliarino, Massaciuccoli Regional Park (central-western Italy). We calculate a set of agri-environmental indicators both at territory and farm scale in order to point out the changes occurred over almost twenty years in the farms’ structure, management and production features. The results showed that the major differences were related to fertilisers management (clearly decreasing), to the reduction of some crop types (industrial crops) and to the strong decrease of the gross marketable production. Furthermore, apparently stable indicators, such as the utilised agricultural area and the farm tractors’ power, were actually the result of the compensation of contrasting trends. Farmers’ behaviours were substantially homogeneous within the same typology of farm, highlighting common evolution strategies. The desirability of the occurred changes was also evaluated, underlining the improvement of environmental sustainability of the current cropping systems and a greater social acceptability of agricultural activities, while the evaluation from the farmers’ point of view was less satisfactory

    An integrated assessment framework for the analysis of multiple pressures in aquatic ecosystems and the appraisal of management options

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    The contribution illustrates an integrated assessment framework aimed at evaluating the relationships between multiple pressures and water body status for the purposes of river basin management. The framework includes the following steps. (1) Understanding how the different pressures affect the status of water bodies. This entails the characterization of biophysical state variables and the definition of a causal relationship between pressures and status. Therefore this step involves interaction between experts bearing ecological understanding and experts providing models to represent the effect of pressures. (2) Identifying the relevant pressures to be addressed through appropriate measures to improve the status of water bodies. (3) Evaluating reduction targets for the relevant pressures identified in a river basin, by weighting the effort associated to reducing individual pressures and the potential benefits in terms of water body status. (4) Designing management measures through a creative process and political discussion of alternative options, balancing costs, benefits and effectiveness based on engineering and economic analysis. (5) Simulating scenarios of implementation of a programme of measures in order to check their effectiveness and robustness against climate and land use change. We discuss the five steps of the assessment framework, and particularly the interaction between science and policy at the different stages. We review the assessment tools required at each step and, for setting optimal pressure reduction targets (step 3), we propose and illustrate a simplified multicriteria approach based on semi-quantitative assessment, which produces frontiers of optimal trade-offs between effort spent on measures, and achievements

    Production of polyhydroxybutyrate by the cyanobacterium cf. Anabaena sp

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    Polyhydroxybutyrate (PHB) production by the cyanobacterium cf. Anabaena sp. was here studied by varying the medium composition and the carbon source used to induce mixotrophic growth conditions. The highest PHB productivity (0.06 gPHB gbiomass−1 d−1) was observed when cultivating cf. Anabaena sp. in phosphorus-free medium and in the presence of sodium acetate (5.0 g L−1 concentration), after an incubation period of 7 days. A content of 40% of PHB on biomass, a dry weight of 0.1 g L−1, and a photosynthetic efficiency equal to the control were obtained. The cyanobacterium was then grown on a larger scale (10 L) to evaluate the characteristics of the produced PHB in relation to the main composition of the biomass (the content of proteins, polysaccharides, and lipids): after an incubation period of 7 days, a content of 6% of lipids (52% of which as unsaturated fatty acids with 18 carbon atoms), 12% of polysaccharides, 28% of proteins, and 46% of PHB was reached. The extracted PHB had a molecular weight of 3 MDa and a PDI of 1.7. These promising results demonstrated that cf. Anabaena sp. can be included among the Cyanobacteria species able to produce polyhydroxyalkanoates (PHAs) either in photoautotrophic or mixotrophic conditions, especially when it is grown under phosphorus-free conditions

    A severe case of neuroleukemiosis caused by B cell chronic lymphocytic leukemia, presenting as mononeuritis multiplex.

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    To report an exceptional case of nerve infiltration by an otherwise benign chronic B cell leukemia, inducing severe mononeuritis multiplex. The patient underwent extensive evaluation, including nerve conduction study and myography, brain and plexus MRI, and nerve biopsy. The clinical and electrophysiological diagnosis was a mononeuritis multiplex with severe motor and sensory involvement; only the nerve biopsy allowed definite diagnosis and introduction of chemotherapy, leading to resolution of sensory deficit and progressive motor improvement. Neuroleukemiosis caused by chronic lymphoid leukemia is an exceptional diagnosis. The presence of other possible causes like cryoglobulinemia could induce avoidance of nerve biopsy thus undertreating patient, since steroid treatment is not expected to be efficient on lymphocytic proliferation. Our case stretches the importance of nerve biopsy and raises neuromuscular specialist's awareness of this rare entity

    Ovatoxin-a, a palytoxin analogue isolated from Ostreopsis cf. ovata Fukuyo: cytotoxic activity and ELISA detection

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    This study provides the first evaluation of the cytotoxic effects of the recently identified palytoxin (PLTX) analog, ovatoxin-a (OVTX-a), the major toxin produced by Ostreopsis cf. ovata in the Mediterranean Sea. Its increasing detection during Ostreopsis blooms and in seafood highlights the need to characterize its toxic effects and to set up appropriate detection methods. OVTX-a is about 100 fold less potent than PLTX in reducing HaCaT cells viability (EC50 = 1.1 7 10 129 M vs 1.8 7 10 1211 M, MTT test) in agreement with a reduced binding affinity (Kd = 1.2 7 10 129 vs 2.7 7 10 1211 M, saturation experiments on intact cells). Similarly, OVTX-a hemolytic effect is lower than that of the reference PLTX compound. Ost-D shows the lowest cytotoxicity toward HaCaT keratinocytes, suggesting the lack of a hydroxyl group at C44 as a critical feature for PLTXs cytotoxic effects. A sandwich ELISA developed for PLTX detects also OVTX-a in a sensitive (LOD = 4.2 and LOQ = 5.6 ng/mL) and accurate manner (Bias = 0.3%), also in O. cf. ovata extracts and contaminated mussels. Although in vitro OVTXa appears less toxic than PLTX, its cytotoxicity at nanomolar concentrations after short exposure time rises some concern for human health. The sandwich ELISA can be a viable screening method for OVTXs detection in monitoring program

    Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates

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    Toxin production in marine microalgae was previously shown to be tightly coupled with cellular stoichiometry. The highest values of cellular toxin are in fact mainly associated with a high carbon to nutrient cellular ratio. In particular, the cellular accumulation of C-rich toxins (i.e., with C:N > 6.6) can be stimulated by both N and P deficiency. Dinoflagellates are the main producers of C-rich toxins and may represent a serious threat for human health and the marine ecosystem. As such, the development of a numerical model able to predict how toxin production is stimulated by nutrient supply/deficiency is of primary utility for both scientific and management purposes. In this work we have developed a mechanistic model describing the stoichiometric regulation of C-rich toxins in marine dinoflagellates. To this purpose, a new formulation describing toxin production and fate was embedded in the European Regional Seas Ecosystem Model (ERSEM), here simplified to describe a monospecific batch culture. Toxin production was assumed to be composed by two distinct additive terms; the first is a constant fraction of algal production and is assumed to take place at any physiological conditions. The second term is assumed to be dependent on algal biomass and to be stimulated by internal nutrient deficiency. By using these assumptions, the model reproduced the concentrations and temporal evolution of toxins observed in cultures of Ostreopsis cf. ovata, a benthic/epiphytic dinoflagellate producing C-rich toxins named ovatoxins. The analysis of simulations and their comparison with experimental data provided a conceptual model linking toxin production and nutritional status in this species. The model was also qualitatively validated by using independent literature data, and the results indicate that our formulation can be also used to simulate toxin dynamics in other dinoflagellates. Our model represents an important step towards the simulation and prediction of marine algal toxicity

    A screening study of the spatial distribution and cumulative toxicity of agricultural pesticides in the European Union’s waters

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    Pesticides can be an important stressor to aquatic ecosystems, and their use is strictly regulated in the European Union (EU). However, data on the use of pesticides are rather limited and poorly available, and monitoring is often insufficient to characterize their actual exposure and impact. The aim of the work presented here is to harness the limited data available and assess, for the first time, the distribution of concentrations and toxicity of 148 pesticide active substances (AS) for the whole EU. Starting from available estimates of pesticide use in agriculture and a simple screening-level model of their fate and transport, we quantify pesticide concentrations in soil and water. A comparison with monitoring data shows that predicted water concentrations are in plausible orders of magnitude, hence the model can be regarded as a first-approximation representation of the distribution of pesticides in the environment. The toxicity of individual pesticide active substances (AS) is characterized by their concentrations divided by the respective no observed effect concentrations (NOEC) for aquatic organisms, which represents the “toxic units” (TU) of each AS. The cumulative toxicity of pesticides in soils and streams of the EU is obtained by summing the TU of individual AS. We estimate that the toxicity of individual AS is generally well below 0.1 TU, indicating relatively safe environmental exposure. However, the cumulative toxicity of a mixture of AS can exceed 0.1 toxic units (TU) for more than 27% of the length of the EU’s stream network, and 1 TU for more than 4%. The cumulative toxicity at a given location is driven by only a handful of AS, but these differ from site to site reflecting the variability of pesticide use. Still, we estimate that only about 20 AS out of 148 appear among the top contributors to cumulative toxicity in most cases. While our assessment suggests a relatively widespread risk due to pesticide pollution, it also points to the important limitations concerning knowledge of pesticide use and monitoring of pesticide occurrence in the environment. These limitations need to be addressed in order to evaluate more accurately the effectiveness of EU pesticide policies. The assessment represents a proof-of-concept of a method that can be applied in support of the monitoring of pesticide policies implementation in the EU and elsewhere, once pesticide use can be estimated
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