Obtención de suero anti-Rice stripe necrosis virus por expresión heteróloga de la capside proteica viral

PosterEl entorchamiento del arroz”, causado por el Rice stripe necrosis virus ( es una gran amenaza para el cultivo del arroz en Argentina Hasta la fecha, se desconoce su distribución, cultivares promisoriamente resistentes y no se cuenta con un suero comercial para su detección El objetivo de este trabajo fue la obtención de suero anti RSNV para la detección del virus en un gran número de muestras en simultaneo y de bajo costo.Instituto de Patología VegetalFil: Celli, Marcos Giovani. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Celli, Marcos Giovani. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Bangratz, M. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Pinel Galzi, A. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Brizard, J.P. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Hébrard, E. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Brugidou, C. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); Franci

Historical Contingencies Modulate the Adaptability of Rice Yellow Mottle Virus

The rymv1-2 and rymv1-3 alleles of the RYMV1 resistance to Rice yellow mottle virus (RYMV), coded by an eIF(iso)4G1 gene, occur in a few cultivars of the Asiatic (Oryza sativa) and African (O. glaberrima) rice species, respectively. The most salient feature of the resistance breaking (RB) process is the converse genetic barrier to rymv1-2 and rymv1-3 resistance breakdown. This specificity is modulated by the amino acid (glutamic acid vs. threonine) at codon 49 of the Viral Protein genome-linked (VPg), a position which is adjacent to the virulence codons 48 and 52. Isolates with a glutamic acid (E) do not overcome rymv1-3 whereas those with a threonine (T) rarely overcome rymv1-2. We found that isolates with T49 had a strong selective advantage over isolates with E49 in O. glaberrima susceptible cultivars. This explains the fixation of the mutation T49 during RYMV evolution and accounts for the diversifying selection estimated at codon 49. Better adapted to O. glaberrima, isolates with T49 are also more prone than isolates with E49 to fix rymv1-3 RB mutations at codon 52 in resistant O. glaberrima cultivars. However, subsequent genetic constraints impaired the ability of isolates with T49 to fix rymv1-2 RB mutations at codons 48 and 52 in resistant O. sativa cultivars. The origin and role of the amino acid at codon 49 of the VPg exemplifies the importance of historical contingencies in the ability of RYMV to overcome RYMV1 resistance

CNS Delivery Via Adsorptive Transcytosis

Adsorptive-mediated transcytosis (AMT) provides a means for brain delivery of medicines across the blood-brain barrier (BBB). The BBB is readily equipped for the AMT process: it provides both the potential for binding and uptake of cationic molecules to the luminal surface of endothelial cells, and then for exocytosis at the abluminal surface. The transcytotic pathways present at the BBB and its morphological and enzymatic properties provide the means for movement of the molecules through the endothelial cytoplasm. AMT-based drug delivery to the brain was performed using cationic proteins and cell-penetrating peptides (CPPs). Protein cationization using either synthetic or natural polyamines is discussed and some examples of diamine/polyamine modified proteins that cross BBB are described. Two main families of CPPs belonging to the Tat-derived peptides and Syn-B vectors have been extensively used in CPP vector-mediated strategies allowing delivery of a large variety of small molecules as well as proteins across cell membranes in vitro and the BBB in vivo. CPP strategy suffers from several limitations such as toxicity and immunogenicity—like the cationization strategy—as well as the instability of peptide vectors in biological media. The review concludes by stressing the need to improve the understanding of AMT mechanisms at BBB and the effectiveness of cationized proteins and CPP-vectorized proteins as neurotherapeutics

Distribution and Characterization of <i>Rice yellow mottle virus</i>: A Threat to African Farmers

International audienc

Movement of rice yellow mottle virus between xylem cells through pit membranes

The translocation of rice yellow mottle virus (RYMV) within tissues of inoculated and systematically infected #Oryza sativa$ L. leaves was characterized by Western immunoblotting, Northern blotting, and electron microscopy of thin sections. In inoculated leaves, RYMV RNA and coat protein first were detected at 3 and 5 days postinoculation, respectively. By six days postinoculation, RYMV had spread systematically to leaves, and virus particles were observed in most cell types, including epidermal, mesophyll, bundle sheath, and vascular parenchyma cells. Most of the virions accumulated in large crystalline patches in xylem parenchyma cells and sieve elements. Colocalization of a cell wall marker for cellulosic beta-(1-4)-D-glucans and anti-RYMV antibodies over vessel pit membranes suggests a pathway for virus migration between vessels. We propose that the partial digestion of pit membranes resulting from programmed cell death may permit virus migration through them, concomitant with autolysis. In addition, displacement of the Ca2+ from pit membranes to virus particles may contribute to the disruption of the pit membranes and facilitate systemic virus transport. (Résumé d'auteur