Nicotianamine Synthase 2 Is Required for Symbiotic Nitrogen Fixation in Medicago truncatula Nodules

Symbiotic nitrogen fixation carried out by the interaction between legumes and diazotrophic bacteria known as rhizobia requires relatively large levels of transition metals. These elements are cofactors of many key enzymes involved in this process. Metallic micronutrients are obtained from soil by the roots and directed to sink organs by the vasculature, in a process mediated by a number of metal transporters and small organic molecules that facilitate metal delivery in the plant fluids. Among the later, nicotianamine is one of the most important. Synthesized by nicotianamine synthases (NAS), this molecule forms metal complexes participating in intracellular metal homeostasis and long-distance metal trafficking. Here we characterized the NAS2 gene from model legume Medicago truncatula. MtNAS2 is located in the root vasculature and in all nodule tissues in the infection and fixation zones. Symbiotic nitrogen fixation requires of MtNAS2 function, as indicated by the loss of nitrogenase activity in the insertional mutant nas2-1, phenotype reverted by reintroduction of a wild-type copy of MtNAS2. This would result from the altered iron distribution in nas2-1 nodules shown with X-ray fluorescence. Moreover, iron speciation is also affected in these nodules. These data suggest a role of nicotianamine in iron delivery for symbiotic nitrogen fixation

Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited

CHARACTERIZATION OF \u3ci\u3eDICTYOCAULUS\u3c/i\u3e SPECIES (NEMATODA: TRICHOSTRONGYLOIDEA) FROM THREE SPECIES OF WILD RUMINANTS IN NORTHWESTERN SPAIN

Specimens of Dictyocaulus spp. were extracted from the respiratory tracts of 3 ruminant hosts including roe deer (Capreolus capreolus), red deer (Cervus elaphus), and chamois (Rupicapra rupicapra) from wild populations in the province of Leo´n, northwestern Spain. The near-complete nuclear small-subunit ribosomal RNA gene, and 2 regions of the large-subunit ribosomal RNA gene, were amplified by PCR and sequenced. The SSU rDNA gene sequences indicated a high level of similarity between the isolate from C. elaphus and the published sequences for Dictyocaulus eckerti. SSU rDNA gene sequences were identical in the isolates from C. capreolus and R. rupicapra, and both corresponded to published sequences for D. capreolus. The LSU rDNA gene sequences differed in isolates from the latter 2 hosts, indicating the possible presence of an undescribed Dictyocaulus sp. in R. rupicapra. These results showed that the LSU rDNA gene sequences are useful indicators of genetic and species diversity in species of Dictyocaulus

Characterization of Dictyocaulus Species (Nematoda: Trichosfrongyloidea) from Three Species of Wild Ruminants in Northwestern Spain

Specimens of Dictyocaulus spp. were extracted from the respiratory tracts of 3 ruminant hosts including roe deer (Capreolus capreolus), red deer (Cervus elaphus), and chamois (Rupicapra rupicapra) from wild populations in the province of León, northwestern Spain. The near-complete nuclear small-subunit ribosomal RNA gene, and 2 regions of the large-subunit ribosomal RNA gene, were amplified by PCR and sequenced. The SSU rDNA gene sequences indicated a high level of similarity between the isolate from C. elaphus and the published sequences for Dictyocaulus eckerti. SSU rDNA gene sequences were identical in the isolates from C. capreolus and R. rupicapra, and both corresponded to published sequences for D. capreolus. The LSU rDNA gene sequences differed in isolates from the latter 2 hosts, indicating the possible presence of an undescribed Dictyocaulus sp. in R. rupicapra. These results showed that the LSU rDNA gene sequences are useful indicators of genetic and species diversity in species of Dictyocaulus

PD-L1/PD-1/CD80 immune check-point blockade enhances antigen-specific anti-tumor immunity against hematopoyetic tumor cells

Trabajo presentado al: Frontiers in immunomodulation and cancer therapy. CNIO, Madrid, 9-11 julio, 2018.Peer reviewe

Role of PD-L1/PD-1 immune checkpoint in NK cell-mediated hybrid resistance parental transplantable hematopoietic lymphoid A20 tumor cells. Frontiers in immunomodulation and cancer therapy

Trabajo presentado al: Frontiers in immunomodulation and cancer therapy. CNIO, Madrid, 9-11 julio, 2018.Peer reviewe

Mal de Río Cuarto Virus infection triggers the production of distinctive viral-derived siRNA profiles in wheat and Its planthopper vector

Plant reoviruses are able to multiply in gramineae plants and delphacid vectors encountering different defense strategies with unique features. This study aims to comparatively assess alterations of small RNA (sRNA) populations in both hosts upon virus infection. For this purpose, we characterized the sRNA profiles of wheat and planthopper vectors infected by Mal de Río Cuarto virus (MRCV, Fijivirus, Reoviridae) and quantified virus genome segments by quantitative reverse transcription PCR We provide evidence that plant and insect silencing machineries differentially recognize the viral genome, thus giving rise to distinct profiles of virus-derived small interfering RNAs (vsiRNAs). In plants, most of the virus genome segments were targeted preferentially within their upstream sequences and vsiRNAs mapped with higher density to the smaller genome segments than to the medium or larger ones. This tendency, however, was not observed in insects. In both hosts, vsiRNAs were equally derived from sense and antisense RNA strands and the differences in vsiRNAs accumulation did not correlate with mRNAs accumulation. We also established that the piwi-interacting RNA (piRNA) pathway was active in the delphacid vector but, contrary to what is observed in virus infected mosquitoes, virus-specific piRNAs were not detected. This work contributes to the understanding of the silencing response in insect and plant hosts.Inst. de BiotecnologíaFil: De Haro, Luis Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dumon, Analia Delina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Mattio, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Arguello Caro, Evangelina Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Llauger, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Zavallo, Diego. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Blanc, Hervé. Centre National de la Recherche Scientifique. Institut Pasteur, Viruses and RNA Interference Unit; FranciaFil: Truol, Graciela Ana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Mongelli, Vanesa Claudia. Centre National de la Recherche Scientifique. Institut Pasteur, Viruses and RNA Interference Unit; FranciaFil: Saleh, María-Carla. Centre National de la Recherche Scientifique. Institut Pasteur, Viruses and RNA Interference Unit; FranciaFil: Asurmendi, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Del Vas, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin