59 research outputs found

    Isolation of streptomycetes causing common scab from 3-years old potato samples from South America

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    In this paper, we aimed at assessing the best conditions for the isolation of actinobacteria from old potato samples. A set of media and pretreatments were tested. The optimal were chosen for the isolation of actinobacteria from potatoes from Peru, Chile and Argentina. Isolates were tested on the presence of thaxtomin phytotoxin by amplification of the respective gene. Phylogenetic position of strains was compared with their geographical origin, pathogenic potential and existence of common scab (CS) symptoms on potato sample. We demonstrated that RNAlater can be successfully used for the long-term preservation of potato peel for subsequent isolation of actinobacteria on R2A medium. Many streptomycetes were thaxtomin-positive, though they are distantly-related to described pathogens causing CS. Genus Nocardia was first reported to be thaxtomin-positive. Potentially pathogenic strains were isolated not only from infected potato but also from those lacking CS symptoms. Some strains from scabby potatoes were thaxtomin-negative.EEA BalcarceFil: Rapoport, Daria. Charles University in Prague. Faculty opf Science, RepĂșblica Checa. Crop Research Institute, Laboratory of Epidemiology and Ecology of Microorganisms, RepĂșblica Checa.Fil: Patrmanova, T. Crop Research Institute, Laboratory of Epidemiology and Ecology of Microorganisms, RepĂșblica Checa.Fil: Kopecky, J. Crop Research Institute, Laboratory of Epidemiology and Ecology of Microorganisms, RepĂșblica Checa.Fil: Mareckova, M. Crop Research Institute, Laboratory of Epidemiology and Ecology of Microorganisms, RepĂșblica Checa. Czech University of Life Sciences, Faculty of Agrobiology, Food, and Natural Resources, Department of Microbiology, RepĂșblica Checa.Fil: Clemente, Gladys. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Agropecuaria Balcarce; Argentina.Fil: Salvalaggio, Andrea Eugenia. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Agropecuaria Balcarce; Argentina

    Structure and activity of lacustrine sediment bacteria involved in nutrient and iron cycles

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    Knowledge about the bacterial community structure in sediments is essential to better design restoration strategies for eutrophied lakes. In that regard, the aim of this study was to quantify the abundance and activity of bacteria involved in nutrient and iron cycling in sediments from four Azorean lakes with distinct trophic states (Verde, Azul, Furnas and Fogo). Inferred from quantitative PCR, bacteria performing anaerobic ammonia oxidation, were the most abundant in the eutrophic lakes Verde, Azul and Furnas (4.5 % to 16.6 %), followed by nitrifying bacteria (0.8 % to 13.0 %), denitrifying bacteria (0.5 % to 6.8 %), iron-reducing bacteria (0.2 % to 1.4 %), and phosphorus-accumulating organisms (<0.3 %). In contrast, denitrifying bacteria dominated sediments from the oligo-mesotrophic lake Fogo (8.8 %). Activity assays suggested that bacteria performing ammonia oxidation (aerobic and anaerobic), nitrite oxidation, heterothrophic nitrate reduction, iron reduction and biological phosphorus storage/release were present and active in all Azorean lake sediments. The present work also suggested that the activity of denitrifying bacteria might contribute to the release of phosphorus from sediments.The authors are indebted and grateful to the Regional Department of Water Resources and Land Planning (Azores) for the grant (Contrato Excepcionado no. 4/2008/ DROTRH) and its staff (Dina Pacheco), and to Virgilio Cruz and Paulo Antunes (Geosciences Department, University of Azores) for the useful help in sediments' collection, to the technical staff of the Department of Environmental Engineering - DTU for chemical analysis, to Laurent Philippot (INRA - University of Burgundy) for positive controls for DNB, to Richard Glaven and Derek Lovley (Department of Microbiology, University of Massachusetts) for Geobacter strains, to Paul Bodelier, Marzia Milleto and Marion Meima (Netherlands Institute of Ecology, NIOO-KNAW) for SRB clones and to Yunhong Kong and Per Halkjaer Nielsen (Department of Life Sciences, Section of Environmental Engineering, Aalborg University) for PAO clones. The authors also acknowledge the Grant SFRH/BD/25639/2005 from the Foundation for Science and Technology/M.C.T.(Portugal) awarded to G. M. and a Marie Curie Excellence Award (EC FP6) to B.F.S

    Experimental Assessment of the Water Quality Influence on the Phosphorus Uptake of an Invasive Aquatic Plant: Biological Responses throughout Its Phenological Stage

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    International audienceUnderstanding how an invasive plant can colonize a large range of environments is still a great challenge in freshwater ecology. For the first time, we assessed the relative importance of four factors on the phosphorus uptake and growth of an invasive macrophyte Elodea nuttallii (Planch.) St. John. This study provided data on its phenotypic plasticity, which is frequently suggested as an important mechanism but remains poorly investigated. The phosphorus uptake of two Elodea nuttallii subpopulations was experimentally studied under contrasting environmental conditions. Plants were sampled in the Rhine floodplain and in the Northern Vosges mountains, and then maintained in aquaria in hard (Rhine) or soft (Vosges) water. Under these conditions, we tested the influence of two trophic states (eutrophic state, 100 mu g.l(-1) P-PO43- and hypertrophic state, 300 mu g.l(-1) P-PO43-) on the P metabolism of plant subpopulations collected at three seasons (winter, spring and summer). Elodea nuttallii was able to absorb high levels of phosphorus through its shoots and enhance its phosphorus uptake, continually, after an increase of the resource availability (hypertrophic > eutrophic). The lowest efficiency in nutrient use was observed in winter, whereas the highest was recorded in spring, what revealed thus a storage strategy which can be beneficial to new shoots. This experiment provided evidence that generally, the water trophic state is the main factor governing P uptake, and the mineral status (softwater > hardwater) of the stream water is the second main factor. The phenological stage appeared to be a confounding factor to P level in water. Nonetheless, phenology played a role in P turnover in the plant. Finally, phenotypic plasticity allows both subpopulations to adapt to a changing environment

    The contributions to long-term health-relevant particulate matter at the UK EMEP supersites between 2010 and 2013: Quantifying the mitigation challenge

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    Human health burdens associated with long-term exposure to particulate matter (PM) are substantial. The metrics currently recommended by the World Health Organization for quantification of long-term health-relevant PM are the annual average PM10 and PM2.5 mass concentrations, with no low concentration threshold. However, within an annual average, there is substantial variation in the composition of PM associated with different sources. To inform effective mitigation strategies, therefore, it is necessary to quantify the conditions that contribute to annual average PM10 and PM2.5 (rather than just short-term episodic concentrations). PM10, PM2.5, and speciated water-soluble inorganic, carbonaceous, heavy metal and polycyclic aromatic hydrocarbon components are concurrently measured at the two UK European Monitoring and Evaluation Programme (EMEP) ‘supersites’ at Harwell (SE England) and Auchencorth Moss (SE Scotland). In this work, statistical analyses of these measurements are integrated with air-mass back trajectory data to characterise the ‘chemical climate’ associated with the long-term health-relevant PM metrics at these sites. Specifically, the contributions from different PM concentrations, months, components and geographic regions are detailed. The analyses at these sites provide policy-relevant conclusions on mitigation of (i) long-term health-relevant PM in the spatial domain for which these sites are representative, and (ii) the contribution of regional background PM to long-term health-relevant PM. At Harwell the mean (±1 sd) 2010–2013 annual average concentrations were PM10 = 16.4 ± 1.4 ÎŒg m−3 and PM2.5 = 11.9 ± 1.1 ÎŒg m−3 and at Auchencorth PM10 = 7.4 ± 0.4 ÎŒg m−3 and PM2.5 = 4.1 ± 0.2 ÎŒg m−3. The chemical climate state at each site showed that frequent, moderate hourly PM10 and PM2.5 concentrations (defined as approximately 5–15 ÎŒg m−3 for PM10 and PM2.5 at Harwell and 5–10 ÎŒg m−3 for PM10 at Auchencorth) determined the magnitude of annual average PM10 and PM2.5 to a greater extent than the relatively infrequent high, episodic PM10 and PM2.5 concentrations. These moderate PM10 and PM2.5 concentrations were derived across the range of chemical components, seasons and air-mass pathways, in contrast to the highest PM concentrations which tended to associate with specific conditions. For example, the largest contribution to moderate PM10 and PM2.5 concentrations – the secondary inorganic aerosol components, specifically NO3− – were accumulated during the arrival of trajectories traversing the spectrum of marine, UK, and continental Europe areas. Mitigation of the long-term health-relevant PM impact in the regions characterised by these two sites requires multilateral action, across species (and hence source sectors), both nationally and internationally; there is no dominant determinant of the long-term PM metrics to target

    Bacterial diversity and abundance of a creek valley sites reflected soil pH and season

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    The effect of environmental factors on bacterial and actinobacterial communities was assessed to predict microbial community structure in natural gradients. Bacterial and actinobacterial communities were studied at four sites differing in vegetation and water regime: creek sediment, wet meadow, dry meadow and deciduous forest located in a shallow valley. The vegetation structure was assessed by phytocoenological releves. T-RFLP and quantitative PCR were used to determine community composition and abundances. Significant relationships between bacterial community structure and selected soil traits at sites located relatively close to each other (within 200 m) were demonstrated. Both the quantity and structure of bacterial communities were significantly influenced by organic matter content, soil moisture and pH. Bacterial diversity was higher in summer, while that of actinobacteria increased in winter. The Simpson’s evenness E was significantly correlated with soil organic matter content. Soil pH had the greatest influence on bacterial community structure showing higher within-site variability in summer than in winter

    The effectiveness of surgery for adults with hallux valgus deformity: a systematic review protocol

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    Objective: To establish the effectiveness of surgery compared to conservatory management for adults with hallux valgus. Inclusion criteria: Types of participants: This review will include adults (18 years or older) with hallux valgus deformity, excluding adults with neurological problems causing foot deformities e.g. cerebral palsy, neuropathy, stroke, Multiple Sclerosis. Types of intervention(s)/phenomena of interest: The review will include any type of hallux valgus surgery compared to no surgery, conservative treatment (such as physical therapy, kinesio taping, orthosis, etc.) and comparison among different types of hallux valgus surgeries will also be included. Types of outcomes: The primary outcome: - gait measures: assessed by any validated assessment tool (such as biomechanical movement analysis, etc.). The secondary outcomes: - quality of life: assessed by any validated assessment tool (such as SF-36, etc.), - patient satisfaction using any validated assessment tool, - pain using any validated pain assessment tool (such as the Visual Analogue Scale, Verbal Rating Scale, McGill Pain Questionnaire, etc.), - adverse events. All the above outcomes measured at the following time points: short-term: 1 year after surgery.Jitka Klugarova, Victoria Hood, Fiona Bath-Hextall, Miloslav Klugar, Jana Mareckova, Zuzana Kelnarov
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