200 research outputs found

    Posidonia oceanica (L.) Delile in its westernmost biogeographical limit (northwestern Alboran Sea): Meadows characterisation, phenology and flowering events

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    Mateo-Ramírez A, Urra J, Rueda J, Marina, Bañares-España E, García Raso E. (2016) Posidonia oceanica (L.) Delile in its westernmost biogeographical limit (northwestern Alboran Sea): Meadows characterisation, phenology and flowering events. Front. Mar, Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00055Posidonia oceanica is a Mediterranean endemic seagrass species that forms meadows covering ca. 2.5–4.5 millions of hectares, representing ca.25 % of the infralittoral and shallow circalittoral (down to 50m) bottoms of the Mediterranean. This seagrass is considered a habitat-engineer species and provides an elevated number of ecosystem services. In addition the Marine Strategy Framework Directive (MSFD, 2008/56/EC) includes seagrass like elements to evaluate the “Good Environmental Status” of the European coasts. Information about their phenological characteristic and structure of the meadows is needed for indicator estimations in order to establish their conservation status. The studied meadows are located in the westernmost limit of the P. oceanica distribution (North-western Alboran Sea) in the vecinity of the Strait of Gibraltar, an Atlantic-Mediterranean water transition area. Four sites were selected from East to West: Paraje Natural de Acantilados de Maro-Cerro Gordo (hereafter Maro), Special Area of Conservation “Calahonda” (hereafter Calahonda), Site of Community Importance Estepona (hereafter Estepona) and Punta Chullera (hereafter Chullera) where P. oceanica present their westernmost meadows. Phenological data were recorded from mid November to mid December in P. oceanica patches located at 2 – 3 m depth. At each site three types of patches (patch area 2 m2, large patches) were sampled. At each patch and site, 3 quadrants of 45 x 45 cm were sampled for shoot and inflorescences density measurements. In each quadrant, 10 random shoots were sampled for shoot morphology (shoot height and number of leaves). Shoot and inflorescences densities were standardized to squared meters. All the studied P. oceanica meadows develop on rocks and they present a fragmented structure with a coverage ranging between ca. 45% in Calahonda and Estepona and ca. 31% in Maro. The meadows of Chullera are reduced to a few small - medium patches with areas ranging between 0.5-1.5 m2 (Fig. 1). The meadows of Chullera and Estepona presented similar values of shoot density (ca. 752 – 662 shoots m-2, respectively) and leaf height (ca. 25 cm). Similarly, the Calahonda and Maro meadows also showed similar values of shoot density (ca. 510 – 550 shoots m-2, respectively) but displaying lower values than those of sites located closer to the Strait of Gibraltar. Regarding patch sizes and leaf height, the longest leaves (ca. 25 cm) were found in medium and large patches, but the number of leaves per shoot were higher in the small and the medium size patches (ca. 6.3 leaves per shoot). Flowering was only detected at the Calahonda meadows with maximum values of ca. 330 inflorescences m-2 (115.2 ± 98.2 inflorescences m-2, n= 9; mean ± SD) (Fig.1). Inflorescence density was not significant different among patches of different sizes. In the Alboran Sea and unlike the studied meadows, extensive beds of P. oceanica occur at the National Park of Cabo de Gata (northeastern Alboran Sea), but from east to west (Strait of Gibraltar), meadows are gradually fragmenting and their depth range decrease from 30m to 2m depth between Cabo de Gata and Chullera, respectively. Probably, the Atlantic influence and the characteristic oceanographic conditions of the Alboran Sea (i.e., higher turbidity, higher water turbulence) represent a developmental limiting factor for P. oceanica at higher depths. Similarities between the meadows located closer to Strait of Gibraltar (Chullera and Estepona) were detected as well as between those more distant (Calahonda and Maro). The first ones showed higher values of shoot densities and leaf heights than the formers, which could be relating to the higher hydrodynamic exposure found at Chullera and Estepona meadows. Regarding flowering events, sexual reproduction in P. oceanica is not common in different locations of the Mediterranean Sea. The available information seems to indicate that flowering represent an irregular event and it is related to high seawater temperature. In fact, the flowering episodes that occurred in Calahonda in November 2015, match with the warmest year ever recorded. This is the third flowering event registered in these meadows located close to the westernmost distributional limit of P. oceanica (Málaga, Alboran Sea), which could indicates that these meadows presents a healthy status. Furthermore, the absence of significant differences in relation to inflorescence density between patches of different sizes may be indicating that the fragmentation does not necessarily influence on the flowering of this seagrass species.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Ejemplos de contextos sociales en los que es importante desarrollar el pensamiento crítico de los ciudadanos

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    El pensamiento crítico se considera clave para que los ciudadanos puedan desenvolverse de forma adecuada en una sociedad cada vez más implicada con la ciencia y la tecnología, como mostró un estudio Delphi realizado con un panel de expertos españoles relacionados con la ciencia resaltándolo como el aspecto del ámbito científico-tecnológico con mayor consenso. Este trabajo profundiza en los contextos sociales que los expertos de dicho estudio Delphi consideraron importantes para desarrollar el pensamiento crítico. Los ejemplos propuestos se categorizaron en tres contextos (salud, medioambiente y recursos naturales) y tres niveles de relevancia en la vida (personal, social y global). Este conjunto de contextos puede ayudar a los ciudadanos a desarrollar su capacidad de pensamiento crítico, tanto en la educación formal como informal.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Ditopic Aza-Scorpiand Ligands Interact Selectively with ds-RNA and Modulate the Interaction upon Formation of Zn2+ Complexes

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    Nucleic acids are essential biomolecules in living systems and represent one of the main targets of chemists, biophysics, biologists, and nanotechnologists. New small molecules are continuously developed to target the duplex (ds) structure of DNA and, most recently, RNA to be used as therapeutics and/or biological tools. Stimuli-triggered systems can promote and hamper the interaction to biomolecules through external stimuli such as light and metal coordination. In this work, we report on the interaction with ds-DNA and ds-RNA of two aza-macrocycles able to coordinate Zn2+ metal ions and form binuclear complexes. The interaction of the aza-macrocycles and the Zn2+ metal complexes with duplex DNA and RNA was studied using UV thermal and fluorescence indicator displacement assays in combination with theoretical studies. Both ligands show a high affinity for ds-DNA/RNA and selectivity for ds-RNA. The ability to interact with these duplexes is blocked upon Zn2+ coordination, which was confirmed by the low variation in the melting temperature and poor displacement of the fluorescent dye from the ds-DNA/RNA. Cell viability assays show a decrease in the cytotoxicity of the metal complexes in comparison with the free ligands, which can be associated with the observed binding to the nucleic acids

    Characterization of the cyanobacterium Oscillatoria sp. isolated from extreme sulphureous water from Los Baños de la Hedionda (S Spain)

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    Los Baños de la Hedionda (Málaga, S Spain) is a natural sulphureous spa (150-200 µM sulphide). Although this high sulphide levels can affect the photosynthetic process, there are numerous photosynthetic microorganisms inhabiting the spa. Among them, we isolated a strain of the cyanobacterium Oscillatoria sp., a genus well known by its tolerance to sulphide. Objectives Firstly, to analyze the photosynthetic characteristics and growth rate of the isolated strain, as well as the effect of the presence of sulphide in both processes. Secondly, to determine the limit of genetic adaptation of this strain to sulphide. Methods The resistance of the isolated strain to sulphide was studied by analyzing the effect of increasing sulphide levels (up to 1600 µM) on photosynthetic performance and growth. The limit of genetic adaptation was explored using an evolutionary experimental design named as ratchet protocol. This design allows discerning the maximum capacity of genetic adaptation of Oscillatoria sp. to the exposure of increasing doses of sulphide Conclusions The strain showed maximum growth rates at 200 µM sulphide although reduced rates can be found up to 800 µM sulphide. A significant increase in resistance was achieved in all derived populations during the ratchet experiment (surviving at sulphide concentrations higher than 2 mM). Moreover, they showed different evolutionary potential to adapt to sulphide, depending on historical contingency.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Spanish Ministry of Science and Innovation through CGL2014-53682-P project. Predoctoral State Grant from Scientific and Technical Research and Innovation Plan, Spanish Ministry of Economy, Industry and Competitiveness I+D+i ECC/1402/2013, 201

    Copper(II) complexes of quinoline polyazamacrocyclic scorpiand-type ligands: X-ray, equilibrium and kinetic studies

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    The formation of Cu(II) complexes with two isomeric quinoline-containing scorpiand-type ligands has been studied. The ligands have a tetraazapyridinophane core appended with an ethylamino tail including 2-quinoline (L1) or 4-quinoline (L2) functionalities. Potentiometric studies indicate the formation of stable CuL2+ species with both ligands, the L1 complex being 3–4 log units more stable than the L2 complex. The crystal structure of [Cu(L1)](ClO4)2·H2O shows that the coordination geometry around the Cu2+ ions is distorted octahedral with significant axial elongation; the four Cu–N distances in the equatorial plane vary from 1.976 to 2.183 Å, while the axial distances are of 2.276 and 2.309 Å. The lower stability of the CuL22+ complex and its capability of forming protonated and hydroxo complexes suggest a penta-dentate coordination of the ligand, in agreement with the type of substitution at the quinoline ring. Kinetic studies on complex formation can be interpreted by considering that initial coordination of L1 and L2 takes place through the nitrogen atom in the quinoline ring. This is followed by coordination of the remaining nitrogen atoms, in a process that is faster in the L1 complex probably because substitution at the quinoline ring facilitates the reorganization. Kinetic studies on complex decomposition provide clear evidence on the occurrence of the molecular motion typical of scorpiands in the case of the L2 complex, for which decomposition starts with a very fast process (sub-millisecond timescale) that involves a shift in the absorption band from 643 to 690 nm

    Disentangling mechanisms involved in the adaptation of the cyanobacterium Microcystis aeruginosa to the extreme sulphureous water from Los Baños de la Hedionda (S Spain)

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    Backgrounds Los Baños de la Hedionda (Málaga, S Spain) is a natural sulphureous spa where sulphide can reach a concentration of 150-200 µM. Although this ion has biocide properties, including inhibition of the photosynthetic process, a rich flora can be found in this extreme environment. Objectives To study the adaptation mechanisms allowing resistance of photosynthetic microorganisms to these sulphureous waters Methods For this purpose, a modified Luria–Delbrück fluctuation analysis was carried out. The adaptation to La Hedionda waters of three different strains of the cyanobacterium Microcystis aeruginosa (Kützing) Kützing (isolated from a non-sulphureous freshwater reservoir) was analyzed in order to find out if it was achieved by a physiological adaptation process (acclimation) or by the selection of rare spontaneous mutations (genetic adaptation). Conclusions Several resistant strains were obtained after 6 weeks of cultivation with La Hedionda waters. The fluctuation analysis showed that genetic adaptation was the phenomenon that allowed resistant M. aeruginosa cells from the three strains to survive, with similar mutation rates in the order of magnitude of 1 mutant resistant cell per 106-107 cell division-1. It could be hypothesized that this cyanobacterium could adapt to sulphureous environment by the selection of favoured mutants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Spanish Ministry of Science and Innovation through CGL2014-53682-P project. Predoctoral State Grant from Scientific and Technical Research and Innovation Plan, Spanish Ministry of Economy, Industry and Competitiveness I+D+i ECC/1402/2013, 201

    Overdentures-supported with implants in totally edentulous geriatric patients

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    En la actualidad, la implantología oral constituye una modalidad terapéutica en el tratamiento prostodóncico de los pacientes mayores edéntulos totales. La utilización de implantes oseointegrados para rehabilitar la mandíbula o el maxilar edéntulos ha aumentado en el tratamiento de los pacientes geriátricos. La odontología clínica ha demostrado la aplicación con éxito de las técnicas implantológicas orales en los pacientes ancianos. Las sobredentaduras son una excelente modalidad terapéutica de prótesis sobre implantes con una buena respuesta funcional y estética en estos pacientes. La valoración médica y un plan de tratamiento es necesaria para optimizar los beneficios de la rehabilitación oral con sobredentaduras implantosoportadas sobre la calidad de vida de los pacientes geriátricos. Algunos implantes pueden constituir los elementos retentivos, mediante ataches de las sobredentaduras. Los resultados clínicos de muchos estudios demuestran que la rehabilitación prostodóncica mediante una sobredentadura con implantes de los pacientes edéntulos representa una terapéutica implantológica con éxito

    Scientific Modelling of Socially Acute Questions to Promote Citizenship Action with Preservice Early Childhood Teachers.

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    This paper studies the impact of modelling practice through multiple models. It was carried out in a training programme of collective activism based on scientific practices with preservice early childhood teachers at Málaga University (Spain) during 2021/22. The programme has 4 phases: 1) inquiry, 2) action planning, 3) action and 4) evaluation and reflection. Eleven activist projects were carried out on controversial local issues, selected by 11 teams of 4 or 5 students. The students' answers to two open-ended questions on the assessment of the modelling activity for the development of their activist project are analysed using a system of categories created inductively. According to most students, modelling has had a positive effect on the realisation of their activist projects, not only helping them acquire knowledge but also enabling them to become aware of their views and develop competences to carry out the project. The most difficult part was to identify and/or relate the multiple problem factors in the model and to delimit the project to be represented. However, the quality of the work improved compared to previous years when modelling was not considered.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Correlation between the molecular structure and the kinetics of decomposition of azamacrocyclic copper(II) complexes

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    The formation of copper(II) complexes with symmetrical dinucleating macrocyclic ligands containing two either monomethylated (L1) or trimethylated (L2) diethylenetriamine (Medien or Me3dien) subunits linked by pyridine spacers has been studied by potentiometry. Potentiometric studies show that L1 has larger basicity than L2 as well as higher stability of its mono- and binuclear complexes. The crystal structures of L1·6HCl (1), [Cu2(L1)Cl2](CF3SO3)2 (2), [Cu2(L1)(OH)](ClO4)3·3H2O (3) and [Cu(L1)](ClO4)2 (4) show that L1 adopts different coordination modes when bound to copper(II). Whereas in 2, each copper(II) is bound to one Medien subunit and to one pyridine group, in 3 each metal center is coordinated to one 2,6-di(aminomethyl) pyridine moiety (damp) and to one aminomethyl group. The mononuclear complex 4 shows pseudo-octahedral coordination with two weakly coordinated axial nitrogens. Kinetic studies indicate that complex decomposition is strongly dependent on the coordination mode of L1. Upon addition of an acid excess, all the species except [Cu2(L1)]4+ convert very rapidly to an intermediate that decomposes more slowly to copper(II) and a protonated ligand. In contrast, [Cu2(L1)]4+ decomposes directly without the formation of any detectable intermediate. These results can be rationalized by considering that the crystal structures are maintained in solution and that the weakest Cu–N bonds are broken first, thus indicating that kinetic measurements on complex decomposition can be used to provide information about structural reorganizations in the complexes. In any case, complete decomposition of the L1 complexes takes place in a maximum of two kinetically resolvable steps. However, minor changes in the structure of the complexes can lead to drastic changes in the kinetics of decomposition and the L2 complexes decompose with polyphasic kinetics in which up to four different steps associated with the successive breaking of the different Cu–N bonds can be resolved
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