ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Combined use of GIS and environmental indicators for assessment of chemical, physical and biological soil degradation in a Spanish Mediterranean region
No full textSoil is one of the main non-renewable natural resources in the world. In the Valencian Community (Mediterranean coast of Spain), it is especially important because agriculture and forest biomass exploitation are two of the main economic activities in the region. More than 44% of the total area is under agriculture and 52% is forested. The frequently and or semi-arid climate with rainfall concentrated in few events, usually in the autumn and spring, scarcity of vegetation cover, and eroded and shallow soils in several areas lead to soil degradation processes. These processes, mainly water erosion and salinization, can be intense in many locations within the Valencian Community. Evaluation of soil degradation on a regional scale is important because degradation is incompatible with sustainable development. Policy makers involved in land use planning require tools to evaluate soil degradation so they can go on to develop measures aimed at protecting and conserving soils. In this study, a methodology to evaluate physical, chemical and biological soil degradation in a GIS-based approach was developed for the Valencian Community on a 1/200,000 scale. The information used in this study was obtained from two different sources: (i) a soil survey with more than 850 soil profiles sampled within the Valencian Community, and (ii) the environmental information implemented in the Geo-scientific map of the Valencian Community digitised on an Arc/Info GIS. Maps of physical, chemical and biological soil degradation in the Valencian Community on a 1/200,000 scale were obtained using the methodology devised. These maps can be used to make a cost-effective evaluation of soil degradation on it regional scale. Around 29% of the area corresponding to the Valencian Community is affected by high to very high physical soil degradation, 36% by high to very high biological degradation, and 6% by high to very high chemical degradation. It is, therefore, necessary to draw up legislation and to establish the policy framework for actions focused on preventing soil degradation and conserving its productive potential. (c) 2005 Elsevier Ltd. All rights reserved
Application of a GIS-AF/RF model to assess the risk of herbicide leaching in a citrus-growing area of the Valencia Community, Spain
No full textWe integrated an index-based attenuation factor/retardation factor (AF/RF) model into a GIS to evaluate the risk of leaching of the most frequently applied herbicides (glyphosate, diuron, diquat, bromacil, simazine, linuron, terbuthylazine, and terbumeton) used in citrus orchards of the Valencia Community, Spain. The GIS-model system was applied to a region of 33,800 ha located near Valencia City. The soil and climate data required by the model were stored in an Arc/Info GIS in which the model algorithms were integrated using the AML programming language. A graphical user interface was developed to facilitate the use of the GIS-model system.
The resulting simulation maps indicate that terbumeton, bromacil, and simazine herbicides have the highest risk of leaching because of their high mobility and low Koc (32–158 mg l− 1). The remaining herbicides are strongly adsorbed by clay particles and organic matter, thus minimising the risk of leaching through the soil profile and into groundwater. The obtained ranking of the leaching potential of analysed herbicides is as follows, from highest to lowest risk: terbumeton > bromacil > simazine > terbuthylazine > diuron > linuron > glyphosate > diquat
Beta-lactam antibiotics induce the SOS response and horizontal transfer of virulence factors in Staphylococcus aureus
No full textAntibiotics that interfere with DNA replication and cell viability activate the SOS response. In Staphylococcus aureus, the antibiotic-induced SOS response promotes replication and high-frequency horizontal transfer of pathogenicity island-encoded virulence factors. Here we report that beta-lactams induce a bona fide SOS response in S. aureus, characterized by the activation of the RecA and LexA proteins, the two master regulators of the SOS response. Moreover, we show that beta-lactams are capable of triggering staphylococcal prophage induction in S. aureus lysogens. Consequently, and as previously described for SOS induction by commonly used fluoroquinolone antibiotics, beta-lactam-mediated phage induction also resulted in replication and high-frequency transfer of the staphylococcal pathogenicity islands, showing that such antibiotics may have the unintended consequence of promoting the spread of bacterial virulence factors
Morphometric changes in goat sperm heads induced by cryopreservation
No full textTwo experiments were designed to evaluate the effect of cryopreservation on morphometric characteristics of the goat sperm head. To address this question, we evaluated the size of the sperm head in fresh control cells, post-cooling cells after equilibration with the glycerol preservation solution, and post-thawing cells. Assessment was by automated morphometric sperm head analysis (ASMA) using phase-contrast microscopy without staining. In the first experiment, ASMA was performed on heterospermic pooled samples (fresh, post-cooling after equilibration with the glycerol preservation solution and post-thawing): length, width, area and perimeter were measured. In the second experiment, sperm viability was assessed by Hoechst staining and head morphometry was carried out its before, simultaneously during the cryopreservation process, and the head size was identified for both live and dead spermatozoa. The data were analysed by principal component analysis (PCA). The purpose of PCA is to derive a small number of linear combinations (principal components) from a set of variables (length, width, area and perimeter), that retain as much of the information in the original variables as possible. The main findings that have emerged from this study are that (i) a simple procedure has been developed for measuring spermatozoa heads without staining, which minimises the possibility that sperm head dimensions were influenced by procedural artefacts: (ii) the dimensions of goat sperm heads after cryopreservation in skimmed milk-glucose medium were smaller than in fresh sperm, but this was due to the equilibration phase with the cryoprotectant and not to the cryopreservation process itself, and (iii) dead spermatozoa showed smaller heads than live sperm, consequent upon the loss of membrane function. No differences were observed between post-cooling cells after equilibration with the glycerol preservation solution and post-thawing spermatozoa and only minor osmotic differences between them and fresh sperm were observed. (c) 2006 Elsevier Inc. All rights reserved
Caracterización y potenciales impactos ambientales de las deyecciones ganaderas
Get PDFLas grandes cantidades de deyecciones ganaderas que se generan anualmente en
España hacen que su impacto ambiental sea muy considerable, aunque la extrema
heterogeneidad de sus características, las cuales dependen de una gran variedad de
factores aparte de la especie animal que las origina, hace que aquel sea muy difícil
cuantificar de manera precisa. Por sus especiales características, son las
deyecciones de las explotaciones intensivas de ave y porcino las más relevantes, lo
que las ha hecho objeto de aplicación de las nuevas normativas ambientales
europeas (Directiva IPPC). Si bien los impactos potenciales son numerosos, los
más importantes, así como sus agentes causales, son la generación de gases de
efecto invernadero (metano y óxido nitroso), la acidificación de suelos y aguas
superficiales por gases disueltos en las precipitaciones (amoniaco), la eutrofización
de aguas superficiales por vertidos o escorrentías (nitrógeno y fósforo) y la
contaminación de aguas subterráneas (nitratos). Para controlar y en su caso
minimizar estos impactos es necesaria una adecuada caracterización de las
deyecciones, que tenga en consideración la gran variabilidad de estos materiales,
así como su gestión en las mejores condiciones tanto en las fases de tratamiento y
almacenamiento como en las de aplicación agrícola o aprovechamiento energético
Interference between D and M types of Plum pox virus in Japanese plum assessed by specific monoclonal antibodies and quantitative real-time reverse transcription-polymerase chain reaction
No full textThe dynamics of virus interference between two isolates of Plum pox virus (PPV) belonging to the main PPV types, D and M, were analyzed in Japanese plum (Prunus salicina) by challenge inoculations. To assess the consequences of a PPV-M infection on plum already infected with PPV-D, and vice versa (predominance of one of the strains, recombination, synergism, symptoms aggravation, and so on), 30 Japanese plum trees were graft inoculated with PPV-D or PPV-M isolates in quarantine conditions. One year postinoculation, in the event that the inoculated isolates were detected in the whole plant, a second challenge inoculation (PPV-M or PPV-D, respectively) was performed by grafting. The presence of PPV-D, PPV-M, or both was monitored for 7 years by double-antibody sandwich indirect enzyme-linked immunosorbent assay using specific monoclonal antibodies. Reverse transcription-polymerase chain reaction (RT-PCR) with D- and M-specific primers confirmed the serological typing. Real-time RT-PCR assays were performed using D- and M-specific fluorescent 3′ minor groove binder-DNA probes, which were able to detect and quantify PPV populations in the inoculated plants with greater precision. The presence of PPV-D in Japanese plum did not cross-protect the trees against PPV-M infection. In PPV-D-infected plants, the PPV-M strain used as challenge inoculum behaved differently depending on the plum cultivar assayed. In cv. Black Diamond, PPV-M invaded the plant progressively, displacing the previous PPV-D population; whereas, in cv. Sun Gold, both PPV isolates coexisted in the plant. In contrast, the PPV-D isolate used was unable to infect plants of both cultivars in which a PPV-M population already was established. After 7 years, no synergism was observed and no recombination event between PPV-D and PPV-M genomes was detected
Interactions between nitrogen fertilization and ozone in watermelon cultivar Reina de Corazones in open-top chambers. Effects on chlorophyll alpha fluorescence, lipid peroxidation, and yield
Get PDFWatermelon (Citrillus lanants) plants were grown for two consecutive years in open-top chambers with three different ozone concentrations (O-3-free air, O-3 ambient, and air with additional O-3; CFA, NFA, and NFA+O-3) and three nitrogen fertilizer concentrations [0, 14.0, and 29.6 g N per pot; N0, N1, and N2). There was an interaction between ozone and N fertilizer for the major parameters studied. O-3 and N2 treatments led to a significant decrease in maximum efficiency of photosystem 2 (PS2) photochemistry (F-v/F-m), and induced a significant decrease in the actual quantum yield of PS2 (Phi(PS2)), due mainly to the increased closure of PS2 reaction centres (q(P)) and to an increase in the non-photochemical quenching, (NPQ). On the other hand, these plants exhibited an increased susceptibility to photo inhibition, which could be associated with an increased fraction of reduced Q(A). An increase in lipid peroxidation indicated that damage was occurring at the membrane levels. High N concentration enhanced the detrimental effects of ozone on the fluorescence parameter induction and lipid peroxidation. All these negative alterations led to a decreased yield
maSigPro: a method to identify significantly differential expression profiles in time-course microarray experiments
No full textMotivation: Multi-series time-course microarray experiments are useful approaches for exploring biological processes. In this type of experiments, the researcher is frequently interested in studying gene expression changes along time and in evaluating trend differences between the various experimental groups. The large amount of data, multiplicity of experimental conditions and the dynamic nature of the experiments poses great challenges to data analysis. Results: In this work, we propose a statistical procedure to identify genes that show different gene expression profiles across analytical groups in time-course experiments. The method is a two-regression step approach where the experimental groups are identified by dummy variables. The procedure first adjusts a global regression model with all the defined variables to identify differentially expressed genes, and in second a variable selection strategy is applied to study differences between groups and to find statistically significant different profiles. The methodology is illustrated on both a real and a simulated microarray dataset
Biofilm related infections: Is there a place for conservative treatment of port-related bloodstream infections?
No full textVascular catheters are the most frequently used indwelling medical devices and have become necessary tools for patients with chronic or critical illness. Surgically or percutaneously placed venous access ports are used to facilitate long-term intravenous therapy. The widespread use of these devices has resulted in a dramatic increase in catheter-related infections. It implies considerable morbidity, occasional mortality, and an increase in medical costs derived from its diagnosis, treatment, and mainly, prolongation of the patient's in-hospital stay. Treatment of such infections is often difficult due to the presence of biofilms on the port inner surface; inside the biofilms, bacteria are less vulnerable to antimicrobial agents. Current diagnostic strategies are suboptimal, and most successful treatment options require removal of the infected device followed by a course of antimicrobial therapy. There are limited data concerning the efficacy of antibiotic treatment of port-related bloodstream infections without catheter removal
Post-transcriptional gene silencing of the p23 silencing suppressor of Citrus tristeza virus confers resistance to the virus in transgenic Mexican lime
No full textPreviously, we have shown that most Mexican limes (Citrus aurantifolia (Christ.) Swing.) expressing the p23 gene of Citrus tristeza virus (CTV) exhibit aberrations resembling viral leaf symptoms. Here we report that five independent transgenic lines having normal phenotype displayed characteristics typical of post-transcriptional gene silencing (PTGS): multiple copies of the transgene, low levels of the corresponding mRNA, methylation of the silenced transgene, and accumulation of p23-specific small interfering RNAs (siRNAs). When graft- or aphid-inoculated with CTV, some propagations of these silenced lines were immune: they neither expressed symptoms nor accumulated virions and viral RNA as estimated by DAS-ELISA and Northern blot hybridization, respectively. Other propagations were moderately resistant because they became infected later and showed attenuated symptoms compared to controls. The susceptible propagations, in addition to symptom expression and elevated virus titer, accumulated p23-specific siRNAs at levels significantly higher than immune or non-inoculated propagations, and showed transgene demethylation. This variable response among clonal transformants indicates that factors other than the genetic background of the transgenic plants play a key role in PTGS-mediated resistance