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Coimbra, Portugal

Maleita C.M.,University of Coimbra | Simoes M.J.,Technology Transfer Center | Egas C.,Technology Transfer Center | Curtis R.H.C.C.,Rothamsted Research | de O Abrantes I.M.,IMAR CMA
Plant Disease | Year: 2012

Meloidogyne hispanica infects many economically important crops worldwide. The accurate identification of this pathogen is essential for the establishment of efficient and sustainable integrated pest management programs. Portuguese M. hispanica isolates were studied by biometrical, biochemical, and molecular characteristics. Biometrical characteristics of M. hispanica females, males, and second-stage juveniles were similar to the original description. Biochemical studies revealed a unique enzyme pattern (Hi4) for M. hispanica esterases that allowed for species differentiation. Molecular analysis of the mtDNA region from COII and 16S rRNA genes resulted in amplification products (1,800 bp) similar to M. hispanica, M. ethiopica, and M. javanica, and the described HinfI was unable to discriminate M. hispanica from the other two species. Analysis of the mtDNA sequences revealed altered nucleotides among the isolates that created new restriction sites for AluI and DraIII. The resulting restriction patterns successfully discriminated between the three species, providing a new tool for Meloidogyne identification. Finally, the phylogenetic relationship between M. hispanica and several Meloidogyne spp. sequences was analyzed using mtDNA, confirming the divergence between meiotic and mitotic species and revealing the proximity of M. hispanica to closely related species. Based on the studies conducted, the application of isozyme or polymerase chain reaction restriction fragment length polymorphism analysis would be a useful and efficient methodology for M. hispanica identification. © 2012 The American Phytopathological Society. Source

Dinis P.A.,University of Coimbra | Pinto P.G.A.N.,University of Coimbra | Almeida J.P.V.L.,IMAR CMA | Tavares A.M.O.S.,University of Coimbra | And 2 more authors.
Journal of Maps | Year: 2012

In this work, we analyze the spatial relationships between land-use and lithology in the wine production region of Bairrada (Portugal) and present a new lithological map (1:50,000) created for the region, highlighting the associations with specific types of land-use. The study was focused on the area of Bairrada that establishes the appellation DOC-VQPRD wines. The region shows a heterogeneous lithology and land-use and it is found that these two variables are not independent. Three different zones with characteristic land-use and geology can be distinguished in Bairrada: a western zone where aeolian sand deposits are associated with coniferous forests; an eastern zone with Precambrian and Paleozoic metasedimentary units associated with broad leaf forests; and a central zone with diversified Mesozoic and Cenozoic units in which most vineyards are placed. There is a clear association between a Jurassic marly and dolomitic unit and an occupation by vineyards, which is particularly obvious when larger vineyards are considered. The vineyards are also common when these Jurassic units are covered by relatively thin siliciclastic sediments. © 2012 Journal of Maps. Source

Suan G.,University Claude Bernard Lyon 1 | Mattioli E.,University Claude Bernard Lyon 1 | Pittet B.,University Claude Bernard Lyon 1 | Lecuyer C.,University Claude Bernard Lyon 1 | And 6 more authors.
Earth and Planetary Science Letters | Year: 2010

The Early Toarcian Oceanic Anoxic Event (T-OAE), about 183 myr ago, was a global event of environmental and carbon cycle perturbations, which deeply affected both marine biota and carbonate production. Nevertheless, the long-term environmental conditions prevailing prior to the main phase of marine extinction and carbonate production crisis remain poorly understood. Here we present a ∼ 8 myr-long record of Early Pliensbachian-Middle Toarcian environmental changes from the Lusitanian Basin, Portugal, in order to address the long-term paleoclimatic evolution that ultimately led to carbonate production and biotic crises during the T-OAE. Paleotemperature estimates derived from the oxygen isotope compositions of well-preserved brachiopod shells from two different sections reveal a pronounced ∼ 5 °C cooling in the Late Pliensbachian (margaritatus-spinatum ammonite Zones boundary). This cooling event is followed by a marked ∼ 7-10 °C seawater warming in the Early Toarcian that, after a second cooling event in the mid-polymorphum Zone, culminates during the T-OAE. Calcium carbonate (CaCO3) contents, the amount of nannofossil calcite and the mean size of the major pelagic carbonate producer Schizosphaerella, all largely covary with paleotemperatures, indicating a coupling between climatic conditions and both pelagic and neritic CaCO3 production. Furthermore, the cooling and warming episodes coincided with major marine regressions and transgressions, respectively, suggesting that the growth and decay of ice caps may have exerted a strong control on sea-level fluctuations throughout the studied time interval. This revised chronology of environmental changes shows important similarities with Neogene and Paleozoic episodes of deglacial black shale formation, and thus prompts the reevaluation of ice sheet dynamics as a possible agent of Mesozoic events of extinction and organic-rich sedimentation. © 2009 Elsevier B.V. All rights reserved. Source

Francisco R.,IMAR CMA | Moreno A.,University of Coimbra | Morais P.V.,IMAR CMA
BioMetals | Year: 2010

Studies of Cr(VI) toxicity are generally performed using chromate salts in solution, both when studying the effects on prokaryotes and eukaryotes. Some studies on human carcinogenesis and toxicology on bacteria were done using dichromate, but comparison with chromate was never reported before, and dichromate existence was never taken into consideration and usually overlooked. This paper studied comparatively the effect of dichromate and chromate on the physiology of Ochrobactrum tritici strain 5bvl1, a highly Cr(VI)-resistant and reducing microorganism. This study demonstrated that the addition of chromate or dichromate sodium salts to growth medium at neutral pH ended-up in two different solutions with a different balance of chemical species. Cr(VI) was toxic to O. tritici strain 5bvl1, as clearly shown on growth, reduction, respiration, glucose accumulation assays and by comparing cell morphology. Moreover, the addition of sodium dichromate was always more toxic to cells when compared to chromate and achieved a higher inhibition of every parameter studied. The toxicity differences between the two Cr(VI) oxyanions indicate the possibility of a different impact of Cr(VI) contamination on the environment. This may be of major importance, considering the slight acidity of most of the arable lands which favours the presence of dichromate, the more toxic species. © Springer Science+Business Media, LLC. 2010. Source

Sousa T.,IMAR CMA | Chung A.-P.,IMAR CMA | Pereira A.,IMAR CMA | Pereira A.,University of Coimbra | And 3 more authors.
Metallomics | Year: 2013

Severe environmental problems arise from old uranium mines, which continue to discharge uranium (U) via acid mine drainage water, resulting in soil, subsoil and groundwater contamination. Bioremediation of U contaminated environments has been attempted, but most of the conceptual models propose U removal by cell suspensions of anaerobic bacteria. In this study, strain Rhodanobacter A2-61, isolated from Urgeiriça Mine, Portugal, was shown to resist up to 2 mM of U(vi). The conditions used (low nutrient content and pH 5) potentiated the interaction of the toxic uranyl ion with the tested strain. The strain was able to remove approximately 120 μM of U(vi) when grown aerobically in the presence of 500 μM U. Under these conditions, this strain was also able to lower the phosphate concentration in the medium and increased its capacity to take up inorganic phosphate, accumulating up to 0.52 μmol phosphate per optical density unit of the medium at 600 nm, after 24 hours, corresponding approximately to the late log phase of the bacterial culture. Microscopically dense intracellular structures with nanometer size were visible. The extent of U inside the cells was quantified by LS counting. EDS analysis of heated cells showed the presence of complexes composed of phosphate and uranium, suggesting the simultaneous precipitation of U and phosphate within the cells. XRD analysis of the cells containing the U-phosphate complexes suggested the presence of a meta-autunite-like mineral structure. SEM identified, in pyrolyzed cells, crystalline nanoparticles with shape in the tetragonal system characteristic of the meta-autunite-like mineral structures. U removal has been reported previously but mainly by cell suspensions and through release of phosphate. The innovative Rhodanobacter A2-61 can actively grow aerobically, in the presence of U, and can efficiently remove U(vi) from the environment, accumulating it in a structural form consistent with that of the mineral meta-autunite inside the cell, corresponding to effective metal immobilization. This work supports previous findings that U bioremediation could be achieved via the biomineralization of U(vi) in phosphate minerals. © 2013 The Royal Society of Chemistry. Source

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