Long-Term Cocirculation of Two Strains of Pepino Mosaic Virus in Tomato Crops and Its Effect on Population Genetic Variability.

Mixed viral infections are common in plants, and the evolutionary dynamics of viral populations may differ depending on whether the infection is caused by single or multiple viral strains. However, comparative studies of single and mixed infections using viral populations in comparable agricultural and geographical locations are lacking. Here, we monitored the occurrence of pepino mosaic virus (PepMV) in tomato crops in two major tomato-producing areas in Murcia (southeastern Spain), supporting evidence showing that PepMV disease-affected plants had single infections of the Chilean 2 (CH2) strain in one area and the other area exhibited long-term (13 years) coexistence of the CH2 and European (EU) strains. We hypothesized that circulating strains of PepMV might be modulating the differentiation between them and shaping the evolutionary dynamics of PepMV populations. Our phylogenetic analysis of 106 CH2 isolates randomly selected from both areas showed a remarkable divergence between the CH2 isolates, with increased nucleotide variability in the geographical area where both strains cocirculate. Furthermore, the potential virus-virus interaction was studied further by constructing six full-length infectious CH2 clones from both areas, and assessing their viral fitness in the presence and absence of an EU-type isolate. All CH2 clones showed decreased fitness in mixed infections and although complete genome sequencing indicated a nucleotide divergence of those CH2 clones by area, the magnitude of the fitness response was irrespective of the CH2 origin. Overall, these results suggest that although agroecological cropping practices may be particularly important for explaining the evolutionary dynamics of PepMV in tomato crops, the cocirculation of both strains may have implications on the genetic variability of PepMV populations.

In situ hybridization for the localization of two pepino mosaic virus isolates in mixed infections.

In situ hybridization (ISH) is an informative and relatively accessible technique for the localization of viral genomes in plant tissue and cells. However, simultaneous visualization of related plant viruses in mixed infections may be limited by the nucleotide similarity in the genomes and the single chromogenic detection over the same sample preparation. To address this issue, we used two Pepino mosaic virus isolates and performed ISH over consecutive serial cross-sections of paraffin-embedded leaf samples of single and mixed infected Nicotiana benthamiana plants. Moreover, the probe design was optimized to reduce cross-hybridisation, and co-localization was based on the overlapping of consecutive cross-sections from mixed infected leaves; thus, our results showed that both Pepino mosaic virus isolates co-localized in the same leaf tissue. In turn, both isolates were localized in the cytoplasm of the same cells. These results provide valuable information for studying mixed infections in plants by using a simple ISH procedure that is accessible to any pathology laboratory.

Fístula broncoesofágica congénita de diagnóstico tardío / Congenital bronchoesophageal fistula of late diagnosis

Presentamos el caso de una mujer de 52 años con el antecedente de infecciones respiratorias de repetición desde la infancia, que presenta una fístula broncoesofágica (FBE) congénita diagnosticada de forma incidental a raíz de la aparición de disfagia en los últimos meses. Los estudios radiológicos y manométricos demuestran la asociación con megaesófago y acalasia. Se confirmó el diagnóstico de FBE en bronquio principal izqdo. gracias a un tránsito con gastrografín, esofagoscopia y fibrobroncoscopia. El tratamiento fue quirúrgico mediante toracotomía posterolateral izquierda, procediendo a la resección del trayecto fistuloso e invaginación del muñón con sutura de muscularis esofágica (AU)

We report the case of a 52-year-old woman with a history of recurrent respiratory infections, which presents a congenitalbronchoesophageal fistula (BEF) incidentally diagnosed after the appearance of dysphagia in the last months. Theradiological and manometric studies demonstrate the association with megaesophagus and achalasia. Diagnosis of BEFm in the left main bronchus was confirmed thanks to an esophagogram, esophagoscopy and fiberoptic bronchoscopy. The surgical treatment was carried out through a left posterolateral thoracotomy, proceeding to resection of the fistula and invagination of the stump with suture of esophageal muscularis (AU)

Founder effect for a 26-bp deletion in the RFXANK gene in North African major histocompatibility complex class II-deficient patients belonging to complementation group B.

Expression of major histocompatibility complex (MHC) class II genes is controlled at the transcriptional level by at least four trans-acting genes, CIITA, RFXANK, RFX5, and RFXAP. Defects in these regulatory genes result in the absence of MHC class II molecule expression and, thereby, cause a combined immunodeficiency. MHC class II deficiency is inherited as an autosomal recessive trait. Since the first description of the disease, about 70 patients from 50 families have been reported. Forty-three of these families have been classified into four complementation groups: A, B, C, and D. In the largest group, B, the majority of patients are of North African origin. In two of these patients, the same mutation in the RFXANK gene (752delG-25) was identified. We performed a mutation analysis in 20 additional patients belonging to complementation group B and detected the 752delG-25 mutation in 17. All of these patients are of North African origin. A founder effect for this mutation was documented, since all tested patients, except one, display a common haplotype spanning the RFXANK locus.