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(IRN) Artículos post-print
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Mutants of coliphage BF23 able to propagate on smooth strains of Salmonella Typhimurium - Mojica-A, T.; García, E.; Ascaso, Carmen
Mutants of coliphage BF23 able to propágate on smooth strains of
The host range of a bacteriophage can be modified by mutation
(and/or recombination) either of the host and/or of the bacteriophage.
We have previously reported (MOJICA-A & CHARLES, 1975)
that coliphage BF23 was able to propágate on rough strains (mutation
of the host) of Salmonella typhimurium (strains with incomplete
lipopolysaccharide of the cell wall), and that the sensitivity of
rough strains was dependent on the presence of an intact bfe+
gene. Moreover the inability of the phage to propágate on smooth
strains was due to failure of the phage to absorb to the bacterial
Unmutagenized stocks of phage...
Leguminosas y gramineas como base para la tipificación de pastos. II comunidades de caracter subhúmedo y xerofítico - Pastor Piñeiro, Jesús; Oliver, Salvador; Gómez Sal, A.
Using only legume and grass species, we pretend to characterize a group of pastures,
subhumid and xerophytic by means of an ordination analysis. This analysis
differentiates clearly the communities with mesomediterranean bioclimatic characteristics
from those with supramediterranean ones.
The transition between both bioclimatic environments is defined by the "tomillar-
pasto" (al. Brachypodion phoenicoidé) and 'lastonares" (al. Festuco-Poion
ligulatae) according to topographic and soil characteristics.
Given the complex character of these subhumid pastures, in the southem limit
of their distribution área, the use of only these species belonging to the above mentioned
families, is not sufficient to differentiate the main types of communities
described for the studied área, although it does...
Boron, Zinc, Iron, and Manganese Content in Four Grassland Species - Adarve, M. J.; Hernández, A. J.; Gil, A.; Pastor Piñeiro, Jesús
A pot experiment was carríed oul to test the response of the B,
Zn, Fe, and Mn concentraron in four wild herbaceous specics exposcd
to three landñll leachate treatments of increasing concentration of
contaminants. The species tested «ere clustered clover (Trifolium
(¡lomera tum L.), col ton clover (T. tomentosum L.), wall barley
(Hordeum murinum L.), and soft brome (Bromus hordaceus L.). The
legume specics accumulated more Fe and B than the grasses. The
least contaminated leachate (leachate A) significantly increased the
Fe and Mn content in T. glomeratum. Leachate B significantly increased
the Zn content in both clover species and Fe content in T.
glomeratum and H. murinum, while it...
Efecto de diferentes tipos de uso sobre los componentes edáfico y biótico de agroecosistemas de secano - Hernández, A. J.; Pastor Piñeiro, Jesús; Estalrich, E.; Urcelay, A.; Lacasta Dutoit, Carlos
Los principales problemas ambientales asociados con las prácticas cerealistas
en la submeseta sur son la evolución negativa de las características edáficas y su repercusión
en los procesos erosivos. En esta región semiárida interactúan el clima, la topografía, el suelo y la
cubierta vegetal para determinar el grado de degradación del medio. Desde este punto de vista, el
objetivo de este estudio ha sido examinar los componentes edáfico y biológico de los agroecosistemas
subsiguientes a la retirada del cultivo cerealista, en los que la cantidad y el tipo de la cubierta
vegetal son los que controlan la protección del suelo. Como consecuencia de ello la vegetación es
Cubiertas vegetales en olivar y viñedo: balance de diez años en relación al agua del suelo y su monitorización - Pastor Piñeiro, Jesús; Benítez, M.; Hernández, A. J.
Plant covers in olive grove and vineyard: ten years balance in relation to soil water and its monitoring
The conceptual framework affects necessary ecológica! engineering for the sustainability of woody cultivations
in semiarid Mediterranean environments and tries to articúlate the management of several components of these
ecological agroecosystems to optimize soil water without covers irrigation.
This report describes ways of managing plant covers ("weeds" or native legumes) in relation to the prevailing
rainfall régimen. Over the past 10 years, we have been monitoring soil moisture levéis in an extensive olive
plantation and vineyard at different depths under the different plant canopies through standard procedures
(gravimetric followed by...
Preparation and properties of a cross-linked complex between ferredoxin - NADP+ reductase and flavodoxin - Pueyo, José J.; Sancho, Javier; Edmondson, Dale E.; Gómez-Moreno, Carlos
The electrostatically stabilized complex between Anahaena variabilis ferredoxin - NADP' reductase and
Azotobacter vinelandii flavodoxin has been covalently cross-linked by treatment with l-ethyl-3-(3-dimethylaminopropy1)
carbodiimide. The covalent complex exhibits a molecular mass and FMN/FAD content consistent with
that expected for a 1 : 1 stoichiometry of the two flavoproteins. lmmunochemical cross-reactivity is exhibited by the
covalent complex with rabbit antisera prepared separately against each protein. The complex retains NADPH -
ferricyanide diaphorase activity although the K,,, for ferricyanide is increased twofold and the turnover number
is decreased by a factor of two when compared to native reductase. NADPH -cytochrome-c reductase activity
of the complex is observed at a...
An unusual infection mechanism and nodule morphogenesis in white lupin (Lupinus albus) - González-Sama, Alfonso; Lucas, M. Mercedes; Felipe, Mª Rosario de; Pueyo, José J.
The infection of white lupin (
) roots and the early stages in organogenesis
of the lupinoid nodule are characterized in detail in this work.
• Immunolabelling of
) ISLU16 and green fluorescent
protein labelling of
NZP2037, two strains that induce nodulation
, allowed us to monitor the infection and morphogenesis process.
Light and transmission electron microscopy, low-temperature scanning electron
microscopy, fluorescence and confocal microscopy were employed.
• Rhizobia penetrated the root intercellularly at the junction between the root hair
base and an adjacent epidermal cell. Bacteria invaded the subepidermal cortical cell
immediately beneath the root hair through structurally altered cell wall regions. The
newly infected cell divided repeatedly...
Legume nodule senescence: roles for redox and hormone signalling in the orchestration of the natural aging process - Puppo, Alain; Groten, Karin; Bastian, Fabiola; Carzaniga, Raffaella; Soussi, Mariam; Lucas, M. Mercedes; Felipe, Mª Rosario de; Harrison, Judith; Vanacker, Helene; Foyer, Christine H.
Research on legume nodule development has contributed greatly to our current
understanding of plant–microbe interactions. However, the factors that orchestrate
root nodule senescence have received relatively little attention. Accumulating
evidence suggests that redox signals contribute to the establishment of symbiosis
and senescence. Although degenerative in nature, nodule senescence is an active
process programmed in development in which reactive oxygen species (ROS),
antioxidants, hormones and proteinases have key roles. Nodules have high levels of
the redox buffers, ascorbate and glutathione, which are important in the nodulation
process and in senescence. These metabolites decline with N-fixation as the nodule
ages but the resultant decrease in redox buffering capacity does not necessarily
Soil factors and Fe content in wild herbaceous plants - Pastor Piñeiro, Jesús; Hernández, A. J.; Estalrich, E.; Oliver, Salvador
We study the average and range Fe contents in wild plants from pastures located in West and Central Spain, and how
its Fe content is affected by some environmental factors, specially the soil variables: lithology, clay, pH, organic
matter, free CaCOs, exchangeable Ca, Mg, K and Al, available P, total N, water, climate, rainfall, temperature
range and light intensity.
Nine species were studied, four legumes: Trifolium subterraneum L. brachycalycinum Katzn. et Morley, Trifolium
subterraneum L. subterraneum, Trifolium cemuum and Ornithopus compressus; and five grasses: Agrostis
castellana, Bromus hordaceus, Cynodon dactylon, Dactylis glomerata and Holcus lanatus.
In Western Spain, the Fe mean content in T. subterraneum is 171.1...
Factorial analysis of the effect of sugarbeet vinasses on agroecological indices in horticultural field - Díez-Rojo, M. A.; López-Pérez, J. A.; González-López, M. R.; Piedra Buena, A.; Bello, A.; Almendros, G.
The impact on soil of applying sugarbeet vinasses (V) was analyzed through a field experiment in horticulture
greenhouse, arranged in a 23 factorial design. Two levels of three independent variables —application of V, use of
polyethylene cover (PC) on the soil, and soil depth (D)— on various dependent variables were studied. Vinasses favoured
crop yield and reduced the number of Meloidogyne incognita juveniles in soil. The concentrations of N, P and K increased
with the interaction VõD, with PC also increasing N concentration. The amounts of humic acids and humin decreased with
D; fulvic acid concentration increased with V, but decreased with the interaction VõPC....
The topographic data source of digital terrain models as a key element in the accuracy of hydraulic flood modelling - Casas Planes, M. A.; Benito, Gerardo; Thorndycraft, V. R.; Rico, Mayte
The effects of the topographic data source and resolution on the hydraulic modelling of floods were analysed. Seven digital terrain models (DTMs) were generated from three different altimetric sources: a global positioning system (GPS) survey and bathymetry; high-resolution laser altimetry data LiDAR (light detection and ranging); and vectorial cartography (1:5000). Hydraulic results were obtained, using the HEC-RAS one-dimensional model, for all seven DTMs. The importance of the DTM's accuracy on the hydraulic modelling results was analysed within three different hydraulic contexts: (1) the discharge and water surface elevation results from the hydraulic model; (2) the delineation of the flooded area;...
Palaeoflood hydrology: insight into rare events and extreme flood discharges - Benito, Gerardo; Thorndycraft, V. R.
Les études paléohydrologiques permettent la reconstitution de chronologies de crue à partir des traces laissées par les sédiments de crue ou l'érosion du courant. Ces marques géologiques donnent une indication sur le niveau atteint par des crues anciennes, sur des périodes de quelques siècles à plusieurs millénaires. La datation des sédiments s'effectue à partir des matériaux présents dans les dépôts de crue (isotope 14 du carbone ou thermoluminescence de grains de minéraux). Les données paléohydrologiques peuvent ensuite être exploitées d'un point de vue probabiliste, en considérant que les événements recensés ont dépassé un ou plusieurs seuils de niveau. Les différentes...
Evaluation of soil biodesinfestation with crop and garden residues in the control of root-knot nematodes populations. - López-Cepero, J.; Piedra Buena, A.; Díez-Rojo, M. A.; Regalado, R.; Brito, E.; Hernández, Zulimar; Figueredo, M.; Almendros, G.; Bello, A.
Fresh crop and garden residues were applied both under laboratory conditions and in commercial greenhouse in order to asses their effect on soil nematodes populations and soil fertility. In the laboratory experiments, dosages of 5 to 20 g of cabbage residues, chicken manure, cabbage residues+chicken manure, grass+chicken manure, as well as leaves and stems of orange tree, pine tree, oleander, olive tree, palm tree and boxwood were mixed with 500 g soil having root-knot nematodes (Meloidogyne incognita) and soil moisture was adjusted at field capacity. A control treatment without residues was also included. The mixtures were kept into plastic bags,...
Nitrate uptake rates in freshwater plankton: the effect of food web structure - Rojo, Carmen; Rodrigo, María A.; Salazar, Guillem; Álvarez Cobelas, Miguel
Nitrate incorporation rates by primary producers and the transfer of nitrogen to upper planktonic food web
levels in different seasons (spring and summer of different years) were studied using a microcosm experimental approach.
The study communitieswere natural plankton communities from Colgada Lake (central Spain),which is heavily polluted by
nitrate. Natural δ15N in phytoplankton and zooplankton was measured and experiments were performed on the 15N supply.
Naturally derived δ15N varied from 7.4 to 8.6‰ and from 10.0 to 16.8‰ in phytoplankton and zooplankton respectively.
Nitrogen incorporation rates ranged from 0.006 to 0.036μMh−1 and from 0.0004 to 0.0014μMh−1 in phytoplankton
and zooplankton respectively. The differences in natural δ15N...
Microinvertebrate and plant beta diversity in dry soils of a semiarid agricultural wetland complex - Angeler, D. G.; Viedma, Olga; Cirujano, Santos; Álvarez Cobelas, Miguel; Sánchez Carrillo, Salvador
The relationship between environmental features and the β diversity of the propagule bank of dry soils of
temporary wetlands has relevance to ecological theories of community structure and to the conservation of wetland
biodiversity. The correlation of β diversity of microinvertebrates and macrophytes derived from propagules in dry soils
with wetland habitat characteristics, catchment land-use, and the distance between wetlands in a remnant pond complex
in central Spain was assessed. Redundancy analyses showed that β diversity of both groups correlated with habitat
characteristics, whereas associations with catchment agricultural practices were weaker. Nestedness analyses showed
that species-poor communities from degraded sites tended to form nested subsets of...
The effect of desiccation on Pyrenoid structure in the Oceanic lichen Parmelia Laevigata - Brown, D. H.; Ascaso, Carmen; Rapsch, S.
Phycobiont cells of Parmelia laemgata contain chloroplasts with
pyrenoids penetrated by a reticulum of tubules. The occurrence and significance of
such tubules in algae is discussed. Although these tubules collapsed in desiccated
cells, their lumen reappeared on rehydration. However, in such desiccated cells,
pyrenoglobuli did not become peripherally located within the pyrenoid, except when
damage occurred to the pyrenoid matrix. Rehydration of desiccated cells reduced the
number of pyrenoglobuli per pyrenoid.
Bioconstructions in ochreous speleothems from lava tubes on Terceira Island (Azores) - Ríos, Asunción de los; Bustillo, Mª Ángeles; Ascaso, Carmen; Carvalho, M. R.
The ochreous speleothems examined here were obtained from a lava tube on Terceira Island (Azores) and
show compact mineralized areas intermixed with zones in which bacterial structures are evident. Bacterial
layers of filament-like structures are common throughout the deposits but differences in microstructure
among the different speleothems were observed, reflecting a broad morphological range of deposits.
The structures and minerals detected in the speleothems betray their biogenic origin. Gallionella and
Leptothrix were the two most frequently observed morphotypes and probably the main contributors to
speleothem formation. However, DGGE analysis indicated the presence of another bacterial population (with
a predominance of proteobacteria) that could also contribute to iron...
Impactos sobre los ecosistemas terrestres - Valladares, Fernando; Peñuelas, J.; Luis Calabuig, E. de
España presenta una gran variedad de ecosistemas terrestres, muchos de ellos únicos y todos
ellos proporcionando un amplio número de bienes y servicios. Estos ecosistemas han estado
sometidos a intensos cambios climáticos en el pasado pero el ritmo de estos cambios se ha
acelerado de forma excepcional. El cambio climático acelerado está dando lugar a un abanico
de efectos directos e indirectos que se ven acentuados por la interacción con otros motores del
cambio global (cambios de uso del territorio, contaminación, intercambio biótico). Los efectos
difieren para los ecosistemas de la región Atlántica, limitados por temperatura, y para los de la
región Mediterránea, limitados por agua. Mientras...