Fungal endophytes in species of paspalum and bromus, occurrence and in vitro antagonistic activity assessment

The aims of this work were to study the occurrence of fungiassociated to Paspalum dilatatum, P. notatum, Bromus biebersteiniiand B. catharticus and to evaluate their potential as antagonisticagents against fungal pathogens. The genera Acremonium, Alternaria,Aspergillus, Curvularia, Fusarium, Penicillium and Stemphylium werethe most representative isolated fungi. The isolates of the genusAcremonium showed antagonistic activity against different putativepathogenic species tested in dual cultures. The results suggest that theinteractions and mechanisms of antagonism of the same strain varyaccording to the putative pathogenic strains to which they are facedto. The results encourage further studies to elucidate if the strainsisolated in this study are good candidates for biological control of latentpathogens in pastures. To accomplish this, future studies focused onthe analysis of the secondary metabolites produced by the antagonistsin the culture medium, as well as assays in planta will be conducted.Fil: García Lemos, Adriana. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Gil Cardeza, Maria Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Gomez, Elena del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Felitti, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentin

Effective penetration length and interstitial vortex pinning in superconducting films with regular arrays of defects

In order to compare magnetic and non-magnetic pinning we have nanostructured two superconducting films with regular arrays of pinning centers: Cu (non-magnetic) dots in one case, and Py (magnetic) dots in the other. For low applied magnetic fields, when all the vortices are pinned in the artificial inclusions, magnetic dots prove to be better pinning centers, as has been generally accepted. Unexpectedly, when the magnetic field is increased and interstitial vortices appear, the results are very different: we show how the stray field generated by the magnetic dots can produce an effective reduction of the penetration length. This results in strong consequences in the transport properties, which, depending on the dot separation, can lead to an enhancement or worsening of the transport characteristics. Therefore, the election of the magnetic or non-magnetic character of the pinning sites for an effective reduction of dissipation will depend on the range of the applied magnetic field.Comment: 10 pages, 3 figure

Superconducting/magnetic three state nanodevice for memory and reading applications

We present a simple nanodevice that can operate in two modes: i) three-state memory and ii) reading device. The nanodevice is fabricated with an array of ordered triangular-shaped nanomagnets embedded in a superconducting thin film. The input signal is ac current and the output signal is dc voltage. Vortex ratchet effect in combination with out of plane magnetic anisotropy of the nanomagnets is the background physics which governs the nanodevice performance.Comment: 10 pages, 4 figure

Dedekind Superrings

We introduce the concept of a Dedekind superring and study some of its properties. We also define invertible supermodules, fractional superideals, the Picard group of a superring, and the ideal class group of a superring.Comment: 22 pages, comments welcom

Acute glyphosate exposure does not condition the response of microbial communities to a dry-rewetting disturbance in a soil with long history of glyphosate-based herbicides

Dry-rewetting perturbations are natural disturbances in the edaphic environment and particularly in dryland cultivation areas. The interaction of this disturbance with glyphosate-based herbicides (GBHs) deserves special attention in the soil environment due to the intensification of agricultural practices and the acceleration of climate change with an intensified water cycle. The objective of this study was to assess the response of microbial communities in a soil with long history of GBHs to a secondary imposed perturbation (a single dry-rewetting event). A factorial microcosm study was conducted to evaluate the potential conditioning effect of an acute glyphosate exposure on the response to a following dry-rewetting event. A Respiratory Quotient (RQ) based on an ecologically relevant substrate (p-coumaric acid) and basal respiration was used as physiological indicator. Similarly, DNA-based analyses were considered, including quantitative PCR (qPCR) of functional sensitive microbial groups linked to cycles of carbon (Actinobacteria) and nitrogen (ammonia-oxidizing microorganisms), qPCR of total bacteria and denaturing gradient gel electrophoresis (DGGE) of ammonia-oxidizing bacteria (AOB). Significant effects of Herbicide and of Dry-rewetting perturbations were observed in the RQ and in the copy number of amoA gene of AOB, respectively. However, no significant interaction was observed between them when analyzing the physiological indicator and the copy number of the evaluated genes. PCR-DGGE results were not conclusive regarding a potential effect of Dry-rewetting × Herbicide interaction on AOB community structure, suggesting further analysis by deep sequencing of amoA gene. The results of this study indicate that the perturbation of an acute glyphosate exposure in a soil with long-history of this herbicide does not have a conditioning effect on the response to a subsequent dry-rewetting disturbance according to a physiological indicator or the quantified bacterial/archaeal genes. This is particularly relevant for the sustainability of soils in rainfed agriculture, where frequent exposure to GBHs along with intensification of hydrological cycles are expected to occur. Further studies considering multiple dry-rewetting disturbances and in different soil types should be conducted to simulate those conditions and to validate our results.Fil: Allegrini, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Gomez, Elena del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin

Beglund-H\"ubsch transpose and Sasaki-Einstein rational homology 7-spheres

We show that links of invertible polynomials coming from the Johnson and Koll\'ar list of K\"ahler-Einstein 3-folds that are rational homology 7-spheres remain rational homology 7-spheres under the so-called Berglund-H\"ubsch transpose rule coming from classical mirror symmetry constructions. Actually, this rule produces twins, that is, links with same degree, Milnor number and homology H_3, with the exception of iterated Thom-Sebastiani sums of singularities of chain and cycle type, where the torsion and the Milnor number may vary. The Berglund-H\"ubsch transpose rule not only gives a framework to better understand the existence of SasakiEinstein twins but also gives a mechanism for producing new examples of Sasaki-Einstein twins in the rational homology 7 -sphere setting. We also give reasonable conditions for a Sasaki-Einstein rational homology 7-sphere to remain Sasaki-Einstein under the BH-transpose rule. In particular, we found 75 new examples of Sasaki-Einstein rational homology 7-spheres arising as links of not well-formed hypersurface singularities.Comment: We have changed the title, corrected minor typos and added Remark 4.

Modelling the nova rate in galaxies

We compute theoretical nova rates as well as type Ia SN rates in galaxies of different morphological type (Milky Way, ellipticals and irregulars) by means of detailed chemical evolution models, and compare them with the most recent observations. The main difference among the different galaxies is the assumed history of star formation. In particular, we predict that the nova rates in giant ellipticals such as M87 are 100-300 nova/yr, about a factor of ten larger than in our Galaxy (25 nova/yr), in agreement with very recent estimates from HST data. The best agreement with the observed rates is obtained if the recurrence time of novae in ellipticals is assumed to be longer than in the Milky Way. This result indicates that the star formation rate in ellipticals, and in particular in M87, must have been very efficient at early cosmic epochs. We predict a nova rate for the LMC of 1.7 nova/yr, again in agreement with observations. We compute also the K- and B-band luminosities for ellipticals of different luminous mass and conclude that there is not a clear trend for the luminosity specific nova rate with luminosity among these galaxies. However, firm conclusions about ellipticals cannot be drawn because of possible observational biases in observing these objects. The comparison between the specific nova rates in the Milky Way and the LMC indicates a trend of increasing nova rate passing from the Galaxy towards late-type spirals and Magellanic irregulars.Comment: 9 pages, 5 figures, Astronomy and Astrophysics accepte

Suppression treatment differentially influences the microbial community and the occurrence of broad host range plasmids in the rhizosphere of the model cover crop Avena sativa L.

Cover crop suppression with glyphosate-based herbicides (GBHs) represents a common agricultural practice. The objective of this study was to compare rhizospheric microbial communities of A. sativa plants treated with a GBH relative to the mechanical suppression (mowing) in order to assess their differences and the potential implications for soil processes. Samples were obtained at 4, 10, 17 and 26 days post-suppression. Soil catabolic profiling and DNA-based methods were applied. At 26 days, higher respiration responses and functional diversity indices (Shannon index and catabolic evenness) were observed under glyphosate suppression and a neat separation of catabolic profiles was detected in multivariate analysis. Sarcosine and Tween 20 showed the highest contribution to this separation. Metabarcoding revealed a non-significant effect of suppression method on either alpha-diversity metrics or beta-diversity. Conversely, differences were detected in the relative abundance of specific bacterial taxa. Mesorhizobium sequences were detected in higher relative abundance in glyphosate-treated plants at the end of the experiment while the opposite trend was observed for Gaiella. Quantitative PCR of amoA gene from ammonia-oxidizing archaea showed a lower abundance under GBH suppression again at 26 days, while ammonia-oxidizing bacteria remained lower at all sampling times. Broad host range plasmids IncP-1β and IncP-1ε were exclusively detected in the rhizosphere of glyphosate-treated plants at 10 days and at 26 days, respectively. Overall, our study demonstrates differential effects of suppression methods on the abundance of specific bacterial taxa, on the physiology and mobile genetic elements of microbial communities while no differences were detected in taxonomic diversity.Fil: Allegrini, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Gomez, Elena del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Smalla, Kornelia. Julius Kühn-institut; AlemaniaFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin

Notas fiosociológicas sobre las comunidades arbóreas de las Sierras de Cazorla y Segura

The ecological and phytosociological behaviour of the forest in the Cazorla- Segura ranges are studied; the following syntaxa are discused: Paeonio-Quercetum rotundi- foliae, Berberido-Quercetum rotundifoliae, Daphno-Aceretum granatensis, Berberido-Quercetum pyrenaicae, Jun ipero-Pinetum clusianae and Daphno-Pinetum sylvestris. Three new subassociations are described: Paeonio-Quercetum rotundifoliae subas. arbutetosum unedonis, Berberido-Quercetum rotundifoliae subas. quercetosum faginae and Daphno-Aceretum granatensis subas. pistacietosum terebinthi.Se estudia el comportamiento fitosociológico y ecológico de los bosques de las Sierras de Cazorla y Segura, comentando los siguientes sintáxones: Paeonio-Quercetum rotundifoliae, Berberido-Quercetum rotundifoliae, Daphno-Aceretum granatensis, Berberido- Quercetum pyrenaicae, Junipero-Pinetum clusianae y Daphno-Pinetum sylvestris. Se describen tres nuevas subasociaciones: Paeonio-Quercetum rotundifoliae subas. arbutetosum unedonis, Berberido-Quercetum rotundifoliae subas. quercetosum faginae y Daphno-Aceretum granatensis subasociación pistacietosum terebinthi