No abstract

No abstract

Pesticide biodegradation was studied in soil samples of a representative small periurban production unit (Moreno District, Argentina). The mean periods required for the 50 % dissipation of chlorpyrifos (16 days±1 day), procymidone (3.7 days±0.6 day), and trifluralin (3.6 days±0.6 day) were significantly lower than those measured for reference soil samples of a close location, using doses similar to the manufacturer's recommendation. A preliminary screening scheme for pesticide-degrading bacteria on horticultural soil allowed the isolation of nine culturable bacterial strains, eight of which belonged to Pseudomonas genus. In order to consider the influence of the variability of soil properties on the biodegradation results, humidity, organic matter, conductivity, pH, water retention volume, density, respiration, and total phosphorous content were studied for different soil samples, finding no significant differences in the performed analysis. Overall, although the horticultural activity alters the natural soil, pesticide contamination effects could be reversed by the autochthonous microbial community.

In Buenos Aires periurban area, horticultural practices are one of the most important activities. Pesticides and fertilisers are used without any control to cover the farmers' needs, obtaining high crop yields at short terms and modifying soil ecosystem in the long term. The aim of this work was to isolate indigenous strains from periurban horticultural units with pesticide degrading capacity and to evaluate their plant growth-promoting properties in order to design biofertilisers to be applied in the restoration of these exploited soils. After the screening, eight strains were isolated and identified. They showed not only the capacity to produce indole-3-acetic acid, to fix nitrogen, to secrete siderophores and to solubilise calcium phosphate but also tolerated the mixture of pesticides usually used for horticultural practices. By their behaviour in mixed cultures and plant growth-promoting properties, these autochthonous isolates represent a promising alternative as biofertilisers according to soil type and activity.

No abstract

The sanitary problem of Aedes aegypti mosquito acquires relevance around the world because it is the vector of dengue, zika, chikungunya and yellow fever. The vector is adapting to southern regions faster, and the propagation of these diseases in urban areas is a complex problem for society. We aimed to contribute to the risk prevention of disease transmission in the Metropolitan Area of Buenos Aires, through monitoring Aedes aegypti population levels and developing education campaigns with government agencies and society participation. Monitoring activities aimed to diagnose the presence of the vector and its ecology behaviour, and to generate education and prevention politics to avoid its propagation. The results show that (1) the mosquito is in the territory and it is spreading, (2) prevention activities of the municipalities are insufficient to generate an effective sanitary response and (3) it is necessary to improve the education programmes to the population about the life cycle of the vector. The integration of university, government and society improved the work of the team because it combined knowledge about vector ecology, diseases and territory characteristics.

Soil sterilization is generally used to eliminate or reduce microbial activity in studies involving microbial inoculations, soil enzymes, among others. Achieving an adequate sterility condition is not straightforward due to the variety of resistance structures that are generated in soil microbial ecosystems and the reservoirs that can form between soil aggregates. This is why finding an effective method to achieve good sterilization is important in methodological terms, so the present work aims to compare the effectiveness of three widely used methodologies to sterilize soil and to evaluate their cost/benefit in terms of time and inputs invested. Four treatments were tested: gamma irradiation, sterilization cycles at different times: three cycles of 1 h each and four cycles of 15 min each, and chloroform vapors. The evaluation and comparison of all samples sterilized by the different methodologies were based on the total aerobic heterotrophic bacterial count. The results of this study suggest that it is more efficient to use autoclaving methods because the process is more accessible in terms of equipment and methodologies, and the final results are the same. In the case of this work, sterilization with chloroform vapors had to be rejected. While the use of gamma radiation may be more efficient in terms of time, it can be a costly and inaccessible service for some laboratories that do not have the equipment. Therefore, the most viable options in terms of time, cost, and benefit are those using autoclaves. Among these, shorter treatment times mean a reduction in the cost of using the equipment, so the option of 15-minute cycles is desirable.