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Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119 - Walker, Mark C.; Pueyo, José J.; Gómez-Moreno, Carlos
The kinetics of reduction and intracomplex electron
transfer in electrostatically stabilized and covalently
crosslinked complexes between ferredoxin-NADP+
reductase (FNR) and flavodoxin (Fld) from the cyanobacterium
Anabuena PCC 7119 were compared
using laser flash photolysis. The second-order rate
constant for reduction by 5-deazariboflavin semiquinone
(dRfII) of FNR within the electrostatically stabilized
complex at 10 mM ionic strength (4.0 X 10s M-’
s-‘) was identical to that for free FNR. This suggests
that the FAD cofactor of FNR is not sterically hindered
upon complex formation. A lower limit of approximately
7000 s-l was estimated for the first-order rate
constant for intracomplex electron transfer from
FNRmd to Fl&, under these conditions. In contrast, for
the covalently crosslinked complex,...
Forests are not immune to plant invasions: phenotypic plasticity and local adaptation allow Prunella vulgaris to colonize a temperate evergreen rainforest - Godoy, Óscar; Saldaña, Alfredo; Fuentes, Nicol; Valladares, Fernando; Gianoli, Ernesto
In the South American temperate evergreen rainforest (Valdivian forest), invasive plants are mainly restricted to open sites, being rare in the shaded understory. This is consistent with the notion of closed-canopy forests as communities relatively resistant to plant invasions. However, alien plants able to develop shade tolerance could be a threat to this unique forest. Phenotypic plasticity and local adaptation are two mechanisms enhancing invasiveness. Phenotypic plasticity can promote local adaptation by facilitating the establishment and persistence of invasive species in novel environments. We investigated the role of these processes in the recent colonization of Valdivian forest understory by the...
Flowering phenology of invasive alien plant species compared with native species in three Mediterranean-type ecosystems - Godoy, Óscar; Richardson, David M.; Valladares, Fernando; Castro-Díez, Pilar
[Background and Aims]: Flowering phenology is a potentially important component of success of alien species, since elevated fecundity may enhance invasiveness. The flowering patterns of invasive alien plant species and related natives were studied in three regions with Mediterranean-type climate: California, Spain and South Africa's Cape region. [Methods]: A total of 227 invasive-native pairs were compared for seven character types across the regions, with each pair selected on the basis that they shared the same habitat type within a region, had a common growth form and pollination type, and belonged to the same family or genus. [Key Results]: Invasive alien...
Photoinbition of Photosystem II from Higuer Plants - Yruela Guerrero, Inmaculada; Pueyo, José J.; Alonso, Pablo J.; Picorel Castaño, Rafael
Strong illumination of Cu(II)-inhibited photosystem II
membranes resulted in a faster loss of oxygen evolution
activity compared with that of the intact samples. The
phenomenon was oxygen- and temperature-dependent.
However, D1 protein degradation rate was similar in
both preparations and slower than that found in nonoxygen
evolving PSII particles (i.e. Mn-depleted photosystem
II). These results seem to indicate that during
illumination Cu(II)-inhibited samples do not behave as a
typical non-oxygen evolving photosystem II. Cytochrome
b559 was functional in the presence of Cu(II).
The effect of Cu(II) inhibition decreased the amount of
photoreduced cytochrome b559 and slowed down the
rate of its photoreduction. The presence of Cu(II) during
illumination seems to protect P680 against photodamage
Invasive species can handle higher leaf temperature under water stress than Mediterranean natives - Godoy, Óscar; Pires de Lemos-Filho, J.; Valladares, Fernando
Thermal tolerance of Photosystem II (PSII) highly influences plant distribution worldwide because it
allows for photosynthesis during periods of high temperatures and water stress, which are common in
most terrestrial ecosystems and particularly in dry and semi-arid ones. However, there is a lack of information
about how this tolerance influences invasiveness of exotic species in ecosystems with seasonal
drought. To address this question for Mediterranean-type ecosystems (MTE) of the Iberian Peninsula, we
carried out an experiment with fifteen phylogenetically related species (8 invasive and 7 native, Pinus
pinaster Ait., Pinus radiata D. Don, Schinus molle Linn., Elaeagnus angustifolia L., Eucalyptus globulus Labill.,
Acacia melanoxylon R. Br., Gleditsia...
Nuclear DNA Endoreduplication and Expression of the Mitotic Inhibitor Ccs52 Associated to Determinate and Lupinoid Nodule Organogenesis - González-Sama, Alfonso; Coba de la Peña, Teodoro; Kevel, Zoltan; Mergaert, Peter; Lucas, M. Mercedes; Felipe, Mª Rosario de; Kondorosi, Eva; Pueyo, José J.
Lotus japonicus determinate nodules differ greatly from indeterminate
nodules in their organogenesis and morphological
characteristics, whereas Lupinus albus lupinoid nodules
share features of determinate and indeterminate nodules.
The mitotic inhibitor Ccs52A is essential for endoreduplication
and ploidy-dependent cell enlargement during symbiotic
cell differentiation in Medicago truncatula indeterminate
nodules. ccs52A homolog genes were isolated from lupin and
lotus nodules; the deduced Ccs52A proteins showed high sequence
similarity with other Cdh-1-type activators of the
anaphase-promoting complex and were grouped with A-type
Ccs52 proteins from different plants. In lupin, ccs52A expression
was restricted to the earlier stages of nodule development,
whereas ccs52A transcripts accumulated in lotus
nodule primordia and, to a lesser extent, in mature nodules.
New host races of Meloidogyne arenaria, M. incognita and M. javanica from horticultural regions of Spain - Robertson, L.; Díez-Rojo, M. A.; López-Pérez, J. A.; Piedra Buena, A.; Escuer, M.; López-Cepero, J.; Martínez, C.; Bello, A.
Meloidogyne arenaria (Neal) Chitwood (race 2) is reported for the first time in Jordan. The nematode populations were recovered from several vegetable crops, including tomato (Lycopersicon esulentum Mill), squash (Cucurbita pepo L.), cucumber (Cucumis sativus L.), and bean (Phaseolus vulgaris L.), at Dier Alla in the northern area of the Jordan Valley. Symptoms included root galling, leaf chlorosis, and stunting. Galled plant root samples were collected during a survey conducted from May 2002 to August 2003 covering most of the irrigated agricultural areas of Jordan. Eighty-three Meloidogyne spp. populations were collected from various vegetable crops and fruit trees. Identification to...
Accumulating behaviour of Lupinus albus L. growing in a normal and a decalcified calcic luvisol polluted with Zn - Pastor Piñeiro, Jesús; Hernández, A. J.; Prieto, Nuria; Fernández-Pascual, Mercedes
Lupinus albus L. is a leguminous plant that is starting to generate interest for the phytoremediation
soils showing intermediate metal pollution. Among these metals, Zn causes major phytotoxicity problems
and is common in polluted soils of central Spain. The purpose of this study was to explore the
nutritional behaviour of this plant species towards increasing Zn concentrations in two calcic luvisol
soils: a normal basic soil and a decalcified acid soil. For this purpose the effects of different Zn concentrations
on mineral nutrition, growth, nodulation and nitrogenase activity of nodulated Lupinus
albus cv. Multolupa plants has been investigated. A 12-week trial was performed in pots under
Stress tolerance, genetic analysis and symbiotic properties of root-nodulating bacteria isolated from Mediterranean leguminous shrubs in Central Spain - Ruiz-Díez, Beatriz; Fajardo, Susana; Puertas-Mejía, Miguel Ángel; Felipe, Mª Rosario de; Fernández-Pascual, Mercedes
Nine root-nodulating bacterial isolates were obtained from the leguminous shrubs Spartium junceum, Adenocarpus hispanicus, Cytisus purgans, Cytisus laburnuum, Retama sphaerocarpa and Colutea arborescens in areas of Central Spain. A poliphasic approach analyzing phenotypic, symbiotic and genetic properties was used to study their diversity and characterize them in relation to Mediterranean conditions. Stress tolerance assays revealed marked variations in salinity, extreme pH and cadmium tolerance compared with reference strains, with the majority showing salinity, alkalinity and Cd tolerance and three of them growing at acid pH. Variation within the 16S rRNA gene was examined by amplified 16S rDNA restriction analysis (ARDRA)...
Soil mapping in Spain - Ibáñez, J.J.; Rubio, J.L.; López-Lafuente, A.; Monturiol, F.
The first soil maps representing Spain date from the beginning of the century: the Universal Soil Map of Glinka and that prepared by Sibirtzev and Ramman (Mudarra 1989). The first research work carried out on Spanish soil however must be attributed to E. Huguet del Villar, who was already pioneering soil surveys of the Iberian Peninsula in 1927 on the occasion of the first Intemational Soil Science Congress held in Washington (Huguet del Villar 1927). At that time, he collaborated on the world map drawn up by Stremme. Huguet del Villar's work in Spain, curtailed by the Spanish Civil War,...
Advantages of application of the backscattered electron scanning image in the determination of soil structure and soil constituents - Wierzchos, J.; García González, Maria Teresa; Ascaso, Carmen
Submicroscopic techniques can be broadly subdivided into the study of micromorphology
and imaging of the arrangement of the soil particles and voids, and the microchemical analysis of soil components.
In the authors opinión, one of the most promising tools in the micromorphology study of soil is the Scanning
Electron Microscopy (SEM) operating in Backscattered Electron emission mode (BSE) with the auxiliary Energy Dispersive Spectrometry (EDS) as a microanalytical system. The emission of BSE is strongly related to the atomic number of the target. This allows easy localization of resin in pores and soil mineral particles. Qualitative differences of chemical nature between soil constituents...
Nuevas aplicaciones de las técnicas submicroscópicas en el estudio del biodeterioro producido por talos liquénicos - Ascaso, Carmen; Wierzchos, J.
The advances that have been made on the effect of lichens on rock substrate have been
numerous. The first techniques used in order to know the type of biodeterioration produced by
lichen thalli, were observations by light microscopy. The microchemical techniques that
followed this, such as X-Ray Diffraction and Infrared Spectroscopy, provided knowledge of
the mineral composition of the substrate which is in contact with the lichen thalli. This zone
is known as interface. More recently, the Scanning Electron Microscope has allowed observations
of the relationship between the hyphae of the lower part of the thallus and the topography of
the superficial part of the rock. In...
La contaminación del agua impide la recuperación de Las Tablas de Daimiel - Cirujano, Santos; Álvarez Cobelas, Miguel
La reciente mortandad de al menos 35.000 carpas en las Tablas de Daimiel
por vertidos contaminantes pone de manifiesto que este parque nacional no
sólo necesita agua. También es preciso que la que llega tenga una calidad
mínima que permita la recuperación de este ecosistema singular.
Contenidos de Zn y Cu en especies de gramíneas de pastizales y herbazales desarrollados sobre suelos erosionados y contaminados de Madrid - Pastor Piñeiro, Jesús; Hernández, A.J.
The Madrid province has suffered constant and ever increasing impacts on its natural and
agricultural ecosystems. This has led to soils with problems of erosion, compacting, salinization
and po11ution by organic compounds and heavy metals. A report by the Madrid Autonomous
Community identifies Zn and Cu as the main metal po11utants affecting the soils of Madrid.
Thus, to obtain information for future revegetation and remediation plans for these regions, we
collected some 600 specimens of grass species representing over 20 genera. Samples were also
obtained of the soils in which these species grow both from different degraded ecosystems and
from seminatural pastures. These last samples will be...
Chemical characteristics of sedimentary soils in the Mediterranean environment: a comparison of undisturbed and disturbed soils - Pastor Piñeiro, Jesús; Hernández, A.J.; Adarve, M.J.; Urcelay, A.
In many ecosystems, especially in siliceous soils, the mobile anión balance controls the entire
ionic equilibrium. However, the equilibrium of the mobile anión cycle is very fragüe, and many factors—
abiotic, biotic and, above all, human—constantly disturb it.
This paper reports a study of the principal anions found in the surficial layer of soils situated over
sedimentary substrates in a continental Mediterranean environment, primarily in semiarid regions.
Human (deforestation) and animal activities over decades (overgrazing, trampling) have altered these
soils to different degrees. Recently, their use in some cases as landfills for solid waste has become one of
the major causes of disturbance. Comparisons are made in...