Discovery of an unrecognized nidovirus associated with granulomatous hepatitis in rainbow trout

Rainbow trout (Oncorhynchus mykiss) is the principal species of inland-farmed fish in the Western hemisphere. Recently, we diagnosed in farmed rainbow trout a disease in which the hallmark is granulomatous-like hepatitis. No biotic agents could be isolated from lesions. Still, unbiased high-throughput sequencing and bioinformatics analyses revealed the presence of a novel piscine nidovirus that we named “Trout Granulomatous Virus” (TGV). TGV genome (28,767 nucleotides long) is predicted to encode non-structural (1a and 1 ab) and structural (S, M, and N) proteins that resemble proteins of other known piscine nidoviruses. High loads of TGV transcripts were detected by quantitative RT-PCR in diseased fish and visualized in hepatic granulomatous sites by fluorescence in situ hybridization. Transmission electron microscopy (TEM) revealed coronavirus-like particles in these lesions. Together, these analyses corroborated the association of TGV with the lesions. The identification and detection of TGV provide means to control TGV spread in trout populations

Are ploidy and age size-related? A comparative study on tetraploid Pleurodema kriegi and octoploid P. cordobae (Anura: Leptodactylidae) from Central Argentina

Size differences of anuran amphibian complexes with different ploidy levels are well known, whereas the larger species usually corresponds to a lower ploidy level. Neotropical Pleurodema kriegi (tetraploid) and P. cordobae (octoploid) differ in many morphometric variables and, in all cases, the species with the higher ploidy level corresponded to an increased body size. Although sexual size dimorphism (SSD) has been tested in P. kriegi without considering age-related differences in body size, SSD in P. cordobae is unknown. Here we determined individual age in order to analyse: (1) the intraspecific pattern of SSD of both species and (2) whether a larger body size and lower ploidy level relation observed in other polyploid anuran amphibians are reversed in a tetra-octoploid complex. Age and body size (snout-vent length) were correlated in both sexes and species. When the effect of age was controlled, significant a SSD were found. Intraspecific differences in demographic parameters were significantly higher than interspecific ones. We confirmed a female-biased SSD for both species and found the first case in which the larger species corresponds to a higher ploidy level. Different ploidy levels were an important factor determining age and body size under similar environmental conditions. Skeletochronology provided basic demographic data of P. kriegi and P. cordobae which are now available for comparative and conservation studies.Fil: Otero, Manuel Alejandro. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valetti, Julian Alonso. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bionda, Clarisa de Lourdes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente; ArgentinaFil: Salas, Nancy Edith. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; ArgentinaFil: Martino, Adolfo Ludovico. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; Argentin