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A leachate pollution plume was simulated in a sequential soil columnsystem (SSCS), defined by a longitudinal redox cascade from methanogenic,sulfate-, nitrate-reducing to aerobic conditions. A mixture of contaminants,including compounds such as perchloroethene (PER), 1,1-dichloroethene(DCE), 1,4-dichlorobenzene (DCB), 2-nitrophenol (NP), and benzene (BEN)was supplied to the methanogenic column; their conversion was followed during passage through the SSCS. After establishment of a steady state, parameters were changed to simulate changes in the environment and to follow the reactions of the system. Acetate, initially introduced as an anaerobically easy degradable carbon source, was first omitted and later added again to the system. Furthermore, the medium flow rate and by that the load of the test compounds was increased 4 fold. Changes transiently increased the residual concentrations of most of the xenobiotics. Within seven months after acetate omission, turnover ofcontaminants had almost returned to the original steady state. Flow andload increase resulted in increased transformation of compounds such asPER, NP, and BEN. After readdition of acetate, the turnover of most ofthe xenobiotics increased within the next five weeks.Microbial populations for the anaerobic batch cultures, obtained from thespecific columns, were used to investigate metabolites formed and conversion kinetics of the xenobiotics. Almost the sameconversion pattern was found in batches and columns, except no transformation of DCE and DCB was detected in the SSCS, though both compounds were converted in batch cultures

Water productivity in smallholder rain-fed agriculture is of key interest for improved food and livelihood security. A frequently advocated approach to enhance water productivity is to adopt water harvesting and conservation technologies (WH). This study estimates water availability for potential in situ WH, and supplemental water demand (SWD) in smallholder agriculture in South Africa's Thukela River Basin (29 000 km2, mean annual precipitation 550–2000 mm yr−1). The study includes process dynamics governing runoff generation and crop water demands, quantification of prediction uncertainty, and an analysis of the reliability of in situ WH. The agro-hydrological model SWAT (Soil and Water Assessment Tool) was calibrated and evaluated with the Sequential Uncertainty Fitting algorithm against observed discharge (at ten stations) and maize yield (the dominant crop type) for the period 1997–2006. The water availability was based on the generated surface runoff in smallholder areas. The SWD was derived from a scenario where crop water deficits were met from an unlimited external water source. The reliability was calculated as the percentage of years in which water availability ≥SWD. This reflects the risks of failure induced by the temporal variability in the water availability and the SWD. The calibration reduced the predictive uncertainty and resulted in a satisfactory model performance. For smallholder maize yield, the Root Mean Squared Error was 0.02 t ha−1 during both the calibration and the evaluation periods. The width of the uncertainty band was reduced by 23% due to the calibration. For discharge during the calibration (evaluation) period, the ten-station range in the weighted coefficient of determination (Φ) was 0.16–0.85 (0.18–0.73), and in the coefficient of determination (R2) 0.42–0.83 (0.28–0.72). The calibration reduced the width of the uncertainty band by 25% on average. The results show that the smallholder crop water productivity is currently low in the basin (spatiotemporal median: 0.08–0.22 kg m−3, 95% prediction uncertainty band (95PPU)). Water is available for in situ WH (spatiotemporal median: 0–17 mm year−1, 95PPU) which may aid in enhancing the crop water productivity by meeting some of the SWD (spatiotemporal median: 0–113 mm year−1, 95PPU). However, the reliability of in situ WH is highly location specific and overall rather low. Of the 1850 km2 of smallholder lands, 20–28% display a reliability ≥25%, 13–16% a reliability ≥50%, and 4–5% a reliability ≥75% (95PPU). This suggests that the risk of failure of in situ WH is relatively high in many areas of the basin., Hydrology and Earth System Sciences, 13 (12), ISSN:1027-5606, ISSN:1607-7938

Pseudomonas sp. strain B13 carries the clcRABDE genes encoding chlorocatechol-degradative enzymes on the self-transmissible 105-kb clc element. The element integrates site and orientation specifically into the chromosomes of various bacterial recipients, with a glycine tRNA structural gene (glyV) as the integration site. We report here the localization and nucleotide sequence of the integrase gene and the activity of the integrase gene product in mediating site-specific integration. The integrase gene (int-B13) was located near the right end of the clc element. It consisted of an open reading frame (ORF) of maximally 1,971 bp with a coding capacity for 657 amino acids (aa). The full-length protein (74 kDa) was observed upon overexpression and sodium dodecyl sulfate-polyacrylamide gel electrophoresis separation. The N-terminal 430 aa of the predicted Int-B13 protein had substantial similarity to integrases from bacteriophages of the P4 family, but Int-B13 was much larger than P4-type integrases. The C-terminal 220 aa of Int-B13 were homologous to an ORF flanking a gene cluster for naphthalene degradation in Pseudomonas aeruginosa PaK1. Similar to the bacteriophages phiR73 and P4, the clc element integrates into the 3' end of the target tRNA gene. This target site was characterized from four different recipient strains into which the clc element integrated, showing sequence specificity of the integration. In Pseudomonas sp. strain B13, a circular form of the clc element, which carries an 18-bp DNA sequence identical to the 3'-end portion of glyV as part of its attachment site (attP), could be detected. Upon chromosomal integration of the clc element into a bacterial attachment site (attB), a functional glyV was reconstructed at the right end of the element. The integration process could be demonstrated in RecA-deficient Escherichia coli with two recombinant plasmids, one carrying the int-B13 gene and the attP site and the other carrying the attB site of Pseudomonas putida F1.

The possibilities for low-frequency horizontal transfer of the self-transmissible chlorocatechol degradative genes (clc) from Pseudomonas sp. strain B13 were investigated in activated-sludge microcosms. When the clc genes were transferred into an appropriate recipient bacterium such as Pseudomonas putida F1, a new metabolic pathway for chlorobenzene degradation was formed by complementation which could be selected for by the addition of mono- or 1, 4-dichlorobenzene (CB). Under optimized conditions with direct donor-recipient filter matings, very low transfer frequencies were observed (approximately 3.5 x 10(-8) per donor per 24 h). In contrast, in matings on agar plate surfaces, transconjugants started to appear after 8 to 10 days, and their numbers then increased during prolonged continuous incubation with CB. In activated-sludge microcosms, CB-degrading (CB+) transconjugants of strain F1 which had acquired the clc genes were detected but only when strain B13 cell densities of more than 10(5) CFU/ml could be maintained by the addition of its specific growth substrate, 3-chlorobenzoate (3CBA). The CB+ transconjugants reached final cell densities of between 10(2) and 10(3) CFU/ml. When strain B13 was inoculated separately (without the designated recipient strain F1) into an activated-sludge microcosm, CB+ transconjugants could not be detected. However, in this case a new 3CBA-degrading strain appeared which had acquired the clc genes from strain B13. The effects of selective substrates on the survival and growth of and gene transfer between bacteria degrading aromatic pollutants in a wastewater ecosystem are discussed.

7 páginas, 5 figuras, 1 tabla, [EN] We report on the interference that hydrogen sulfide can generate on the measurement of phosphorus in seawater with the Murphy & Riley method. Free sulfide can be found in a variety of saline systems, from partially closed fjords to eutrophic estuaries, river saline wedges, saline lagoons, etc. in concentrations ranging from 0.02 up to 10 mM and, thus, may be present in water samples without the analysts suspicion. We tested the effects of sulfide concentrations ranging from 0.005 up to 0.7 mM on the measurement of phosphorus concentrations from 10 mgP to 1.5 mgP-PO4 l-1. We characterized spectrophotometrically, the product and the dynamics of the interference and we provide a simple method to detect the interference "a posteriori" by computing the ratio between the absorbances at 350 and 690 nm. If sulfide has been measured in parallel, the absorbances, even those that have had high interference, can be corrected to values without the interference with the equations that we provide. We propose the routine use of this method whenever dealing with samples that could have some sulfide in solution, [ES] El trabajo muestra la intereferencia que el ácido sulfhídrico puede causar en las mediciones de fósforo en agua de mar con el método de Murphy & Riley. Ácido sulfhídrico en forma libre puede encontrase en diversos ecosistemas salinos: fiordos parcialmente cerrados, estuarios eutróficos, cuñas salinas en ríos, lagunas costeras, etc... en concentraciones que oscilan entre 0.02 y 10 mM. Puede, por tanto, encontrarse en muestras sin que el analista lo espere. Comprobamos los efectos de concentraciones de sulfhídrico entre 0.005 y 0.7 mM sobre las mediciones de concentraciones de fósforo entre 10 μgP y 1.5 mgP-PO4 l-1. También caracterizamos espectrofotométricamente el producto y la dinámica de la interferencia y presentamos un método simple para detectar “a posteriori” la interferencia basado en el cálculo de la relación entre las absorbancias a 350 y 690 nm. Si el sulfhídrico fué medido en paralelo, la interferencia puede eliminarse de las absorbancias, incluso si fué muy importante mediante las ecuaciones que proporcionamos. Sugerimos el uso rutinario de este método siempre que deba trabajarse con muestras que pudieran tener sulfhídrico disuelto

ISBN:3-260-04123-0

Food security and water scarcity have become two major concerns for future human's sustainable development, particularly in the context of climate change. Here we present a comprehensive assessment of climate change impacts on the production and water use of major cereal crops on a global scale with a spatial resolution of 30 arc-minutes for the 2030s (short term) and the 2090s (long term), respectively. Our findings show that impact uncertainties are higher on larger spatial scales (e.g., global and continental) but lower on smaller spatial scales (e.g., national and grid cell). Such patterns allow decision makers and investors to take adaptive measures without being puzzled by a highly uncertain future at the global level. Short-term gains in crop production from climate change are projected for many regions, particularly in African countries, but the gains will mostly vanish and turn to losses in the long run. Irrigation dependence in crop production is projected to increase in general. However, several water poor regions will rely less heavily on irrigation, conducive to alleviating regional water scarcity. The heterogeneity of spatial patterns and the non-linearity of temporal changes of the impacts call for site-specific adaptive measures with perspectives of reducing short- and long-term risks of future food and water security., PLoS ONE, 8 (2), ISSN:1932-6203

FEMS Microbiology Ecology, 3 (62), ISSN:0168-6496, ISSN:1574-6941

Force plate or pressure plate analysis came as an innovative tool to biomechanics and sport medicine -- This allows engineers, scientists and doctors to virtually reconstruct the way a person steps while running or walking using a measuring system and a computer -- With this information they can calculate and analyze a whole set of variables and factors that characterize the step -- Then they are able to make corrections and/or optimizations, designing appropriate shoes and insoles for the patient -- The idea is to study and understand all the hardware and software implications of this process and all the components involved, and then propose an alternative solution -- This solution should have at least similar performance to existing systems -- It should increase the accuracy and/or the sampling frequency to obtain better results -- By the end, there should be a working prototype of a pressure measuring system and a mathematical model to govern it -- The costs of the system have to be lower than most of the systems in the market

ISBN:3-905696-19-3

ISBN:3-905641-95-X