Evaluating seasonal dynamics of bacterial communities in marine fish aquaculture: a preliminary study before applying phage therapy

The increasing problem of antibiotic resistance in common pathogenic bacteria and the concern about the spreading of antibiotics in the environment bring the need to find new methods to control fish pathogens. Phage therapy represents a potential alternative to antibiotics, but its use in aquaculture requires a detailed understanding of bacterial communities, namely of fish pathogenic bacteria. Therefore, in this study the seasonal dynamics of the overall bacterial communities, microbiological water quality and disease-causing bacteria were followed in a marine aquaculture system of Ria de Aveiro (Portugal). Analysis of the bacterial diversity of the water samples by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments indicates that the bacterial community structure varied seasonally, showing a higher complexity during the warm season. The diversity of the main fish pathogenic bacteria, assessed by DGGE targeting the Vibrio genus, showed lower seasonal variation, with new dominating populations appearing mainly in the spring. Bacterial indicators, faecal coliforms and enterococci, enumerated by the filter-membrane method, also varied seasonally. The fluorescent in situ hybridization (FISH) results showed that the specific groups of bacteria varied during the study period and that the non-indigenous Enterobactereaceae family was the most abundant group followed by Vibrio and Aeromonas. The seasonal variation detected in terms of density and structure of total and pathogenic bacterial communities demonstrates the need for a careful monitoring of water through the year in order to select the suitable phages to inactivate fish pathogenic bacteria. The spring season seems to be the critical time period when phage therapy should be applied.     

Bio-Based Plastic Based on Ozonated Cassava Starch Produced by Extrusion

Journal of Polymers and the Environment - Green methods of modification, such as ozone, can bring new functionalities to starch. In this study, starch-based plastics were produced by extrusion,...     

Effects of the neurotoxic thionophosphate pesticide chlorpyrifos on differentiating alternative models

Studies by researchers worldwide have revealed that, even in industrialised nations, people, infants and the aged in particular, are even more exposed to neurotoxic drugs as a consequence of the increased quantity of pesticide residues in food. This phenomenon, as underlined by The Worldwatch Institute (2006), is linked to the exponential increase in the use of these toxic compounds over the last 40 years, up from 0.49 kg per hectare in 1961 to 2 kg in 2004, with the result that these substances are found in the daily diet.Many studies have demonstrated how the assumption of pesticides in the neonatal period and early infancy can alter the development and function of the nervous, immune, endocrine and reproductive apparatuses. Moreover, the unequivocal relationship between brain tumours, infant leukemia and pesticides are well recognised.On the basis of the above information, the effects of the neurotoxic thionophosphate pesticide chlorpyrifos (CPF) have been tested, considering biomarkers of toxicity and toxicity endpoint, on the biological models Dictyostelium discoideum, Paracentrotus lividus, and NTera2 Cells, as they are compatible with the 3Rs strategy (Reduction, Replacement, and Refinement in animal experiments). Our results have revealed that developing organisms are particularly sensitive to the toxic effects of CPF.     

Influence of the pesticides glyphosate,chlorpyrifos and atrazine on growth parameters of nonochratoxigenic Aspergillus section Nigri strains isolated from agricultural soils

This investigation was undertake to determine the effect of glyphosate, chlorpyrifos and atrazine on the lag phase and growth rate of nonochratoxigenic A. niger aggregate strains growing on soil extract medium at ?0.70, ?2.78 and ?7.06 MPa. Under certain conditions, the glyphosate concentrations used significantly increased micelial growth as compared to control. An increase of about 30% was observed for strain AN 251 using 5 and 20 mg L^?1 of glyphosate at ?2.78 MPa. The strains behaved differently in the presence of the insecticide chlorpyrifos. A significant decrease in growth rate, compared to control, was observed for all strains except AN 251 at ?2.78 MPa with 5 mg L^?1. This strain showed a significant increase in growth rate. With regard to atrazine, significant differences were observed only under some conditions compared to control. An increase in growth rate was observed for strain AN 251 at ?2.78 MPa with 5 and 10 mg L^?1 of atrazine. By comparison, a reduction of 25% in growth rate was observed at ?7.06 MPa and higher atrazine concentrations. This study shows that glyphosate, chlorpyrifos and atrazine affect the growth parameters of nonochratoxigenic A. niger aggregate strains under in vitro conditions.     

Genetic differentiation between morphotypes in the Antarctic limpet <Emphasis Type="Italic">Nacella concinna</Emphasis> as revealed by inter-simple sequence repeat markers

The limpet Nacella concinna (Strebel 1908) was the focus of numerous studies dealing with Antarctic benthos. One of the main characteristics of the species is the presence of two distinguishable morphotypes, one inhabiting the intertidal (during summer) and the other inhabiting the subtidal. For a long time these forms were considered as an expression of phenotypic plasticity, since previous studies did not found genetic differences between them. In the present work, we performed both a morphometric and a genetic differentiation analysis (using ISSR-PCR markers) of these two forms in three stations sampled at Potter Cove, South Shetland Islands. The results confirmed the morphological differences between intertidal and subtidal forms reported in other Antarctic localities. The genetic differences detected indicate that the two forms can be considered as genetically distinct populations maintaining low levels of gene flow. The degree of reproductive isolation of the ecotypes is discussed, as well as the possible origin of the divergence. The genetic differentiation observed can also have behavioral and physiological correlates, pointing out the importance of taking into account the potential differences in the response of both populations to different conditions in future studies in this species. M. C. de Aranzamendi and R. Sahade contributed equally to this paper.     

Mitigation and adaptation investments for desertification and climate change: an assessment of the socioeconomic return

Climate change will further increase the risk of desertification, which is already affecting large areas of the world. Many countries are making investments for the implementation of mitigation and adaptation strategies to combat desertification. The long term effectiveness of these strategies necessarily require a socioeconomic return for its sustainability. The main goal of our paper is to assess the relation between the mitigation and adaptation investments and the socio-economy of the rural population. The area of study is located in north-central Chile. The northern regions are mostly composed by arid land, which can be considered as a marginal area for agriculture. The area formed by the southern regions is optimal for the agricultural activity which is characterized by an industrialized agriculture with and increased use of technology. The indicators we have used for our study are the following: the Investments provided by the Chilean Agriculture Livestock and Forestry (ALF) promotion agencies, the ALF Gross Domestic Product (GDP) and the Population Employed in ALF. The results show that the relationship between the investments and the socioeconomy varies among the regions analyzed. Investments are positively correlated (P?≤?0.05) with the ALF GDP and the labor in ALF in the northern regions, but do not seem to be directly related to labor in ALF in the southern regions (P?≥?0.05). Therefore, our conclusion is that the Investments are significantly relevant for the agricultural activity in the arid northern regions, while in the southern regions they have no direct impact on the labor in ALF.     

Measuring sustainable development using a multi-criteria model: A case study

This paper shows how Multi-criteria Decision Analysis (MCDA) can help in a complex process such as the assessment of the level of sustainability of a certain area. The paper presents the results of a study in which a model for measuring sustainability was implemented to better aid public policy decisions regarding sustainability. In order to assess sustainability in specific areas, a methodological approach based on multi-criteria analysis has been developed. The aim is to rank areas in order to understand the specific technical and/or financial support that they need to develop sustainable growth.The case study presented is an assessment of the level of sustainability in different areas of an Italian Region using the MCDA approach. Our results show that MCDA is a proper approach for sustainability assessment. The results are easy to understand and the evaluation path is clear and transparent. This is what decision makers need for having support to their decisions. The multi-criteria model for evaluation has been developed respecting the sustainable development economic theory, so that final results can have a clear meaning in terms of sustainability.     

Effects of scrubber by-product-stabilized dairy lagoon sludge on growth and physiological responses of sunflower (Helianthus annuus L.)

Brick manufacturing industries are challenged to comply with clean air mandates. Dry air scrubbers have been used to remove acid gases from the exhaust air from brick manufacturing plants. The use of dry air scrubbers results in the production of large quantities of an alkaline powder by-product. A greenhouse experiment was conducted to evaluate the potential of using dairy lagoon sludge stabilized with the scrubber by-product as a soil amendment. Lagoon sludge was stabilized with scrubber by-product at an application rate of 20 gl(-1). The sludge-scrubber by-product mixture was applied to a sandy loam soil to provide amendments ranging between 28 and 168 kg of plant available nitrogen (PAN)/ha for the growth of Helianthus annuus (sunflower). Use of the sludge-scrubber by-product mixture as a nitrogen fertilizer did not adversely affect sunflower seedling emergence; however, significantly higher (p<0.05) plant volume indices, leaf area, dry shoot and root masses, and seed yields were obtained for mature plants grown in sludge-treated soil relative to the control or fertilizer treatment. The sludge amendment did not severely impact gas exchange or chlorophyll a fluorescence of the plants and nutrient content of the sunflower tissues was generally within a sufficient range. The increased growth and yield of sunflower plants indicated the potential of the sludge-scrubber by-product mixture as a soil amendment in agricultural crop production.