Porcine astrovirus (PAstV) has been poorly studied and has been associated mainly with gastroenteritis. Computational analysis has revealed the close relationship of PAstV with astroviruses of humans (HAstV) and cats (FAstV). In this study, 105 and 171 stool specimens were collected from piglets and children under 5 years of age, respectively, in different Colombian regions during a 1-year period. The stool samples were examined for astroviruses by ELISA and RT-PCR; 23.8% and 4% were found to be positive for PAstV and HAstV, respectively. Additional sequence analysis with partial sequences obtained from ORF2 identified at least 2 probable groups of PAstVs and possible recombination events between porcine and human astroviruses. This study provides preliminary evidence of the high presence of PAstVs in pigs and proposes the existence of multiple PAstV types that are evolutionarily closely related to HAstVs.

Aims: The aim of this study was to determine the antiviral activity of four probiotic metabolites (Lactobacillus and Bifidobacetrium species) against rotavirus in vitro infection monitored by the NSP4 protein production and Ca 2+ release. Methods and Results: The antiviral effect of the metabolites was performed due a comparison between a blocking model and an intracelullar model on MA104 cells, with the response of NSP4 production and Ca 2+ liberation measured by flow cytometry. Significant results were obtained with the metabolites of Lactobacillus casei, and Bifidobacterium adolescentis in the reduction of the protein production (P = 0Á04 and P = 0Á014) and Ca 2+ liberation (P = 0Á094 and P = 0Á020) in the intracellular model, which suggests a successful antiviral activity against RV infection. Conclusions: This study demonstrates that probiotic metabolites were able to interfere with the final amount of intracellular NSP4 protein and a successful Ca 2+ regulation, which suggests a new approach to the mechanism exerted by probiotics against the rotavirus infection. Significance and Impact of the Study: A novel anti-rotaviral effect exerted by probiotic metabolites monitored by the NSP4 protein during the RV in vitro infection and the effect on the Ca 2+ release is reported; suggesting a reduction on the impact of the infection by decreasing the damage of the cells preventing the electrolyte loss.

Background and Objective The characteristics of human hematopoietic stem cells are conditioned by the microenvironment of the bone marrow, where they interact with other cell populations, such as mesenchymal stem cells and endothelial cells; however, the study of this microenvironment is complex. The objective of this work was to develop a 3D culture system by magnetic levitation that imitates the microenvironment of human HSC. Methods and Results Human bone marrow-mesenchymal stem cells, umbilical cord blood-hematopoietic stem cells and a non-tumoral endothelial cell line (CC2811, Lonza ® ) were used to develop organotypic multicellular spheres by the magnetic levitation method. We obtained viable structures with an average sphericity index greater than 0.6, an average volume of 0.5 mm 3 and a percentage of aggregation greater than 70%. Histological studies of the organotypic multicellular spheres used hematoxylin and eosin stains, and an evaluation of vimentin expression by means of immunohistochemistry demonstrated an organized internal structure without picnotic cells and a high expression of vimentin. The functional capacity of human hematopoietic stem cells after organotypic multicellular spheres culture was evaluated by multipotency tests, and it was demonstrated that 3D structures without exogenous Flt3L are autonomous in the maintenance of multipotency of human hematopoietic stem cells. Conclusions We developed organotypic multicellular spheres from normal human cells that mimic the microenvironment of the human hematopoietic stem cells. These structures are the prototype for the development of complex organoids that allow the further study of the biology of normal human stem cells and their potential in regenerative medicine.

BackgroundAchyrocline bogotensis has been traditionally used to treat infections of skin, respiratory, tract urinary and other infections, but not to treat viral gastrointestinal disease. In this study, this Colombian native medicinal plant was investigated by its in vitro anti-rotavirus and anti-astrovirus activity.MethodsSeveral extracts and fractions phytochemically obtained from A. bogotensis were evaluated initially for their cell toxicity on MA104 and Caco2 cells and then for their anti-rotavirus (RRV) and anti-astrovirus (Yuc8) activity following three strategies: pre-treatment of cells (blocking effect), direct viral activity (virucidal effect) and post-treatment of infected cells (reduction of viral yield post-infection). In addition qualitative chemical studies were developed for the active compounds.ResultsNon-toxic concentrations of a fraction obtained exhibited antiviral activity against both viruses characterized by a virucidal effect and by the reduction of the infectious particles produced post-infection. Steroids, sterols, terpenes, phenols, flavonoids and sesquiterpenlactones were identified qualitatively in the active fraction.ConclusionsA. bogotensis contains substances with in vitro antiviral activity against rotavirus and astrovirus. This study confirms their anti-microbial properties and describes by the first time its antiviral activity in vitro.

Rotavirus is recognized worldwide as the main and most important viral pathogen associated with diarrhea in children while norovirus is considered the second cause of epidemic diarrhea in developed countries. Here, we present a comparative study on the prevalence of rotavirus and norovirus in two regions of Colombia: Chocó and Cundinamarca. Five hundred and thirty stool samples were collected; 330 in Cundinamarca and 200 in Chocó. In the sample set from Chocó, 6 % of the samples presented rotavirus and 8 % norovirus; meanwhile, 9.7 % of the samples from Bogotá presented rotavirus and 9 % norovirus. These results show that, in some regions of Colombia, the prevalence of norovirus is similar or slightly higher than rotavirus. This is a tendency that should be examined in other non-developed countries as it suggests that the presence of norovirus should also be under surveillance.

The presence of porcine astroviruses in diarrheic and healthy pigs has been reported, however, the consequences of the astrovirus infection during the weaning process have not been described. In this study, eight healthy conventional newly-weaned piglets were used to evaluate effects of astrovirus infection during the first five days. Four piglets were infected with the porcine astrovirus PoAstV/PUJP5 strain and the other four represented the control group. Body weight, rectal temperature, diarrhea and other clinical signs were monitored every 24 hours. The results showed that all animals gained body weight, the occurrence of mild diarrhea on the 3 rd day post-infection, and the astroviral presence in diarrheic samples. On the 5 th day post-infection all the piglets were euthanized and then intestinal and extra-intestinal tissues were analyzed for the presence of PoAstV/PUJP5. The cytoplasmic antigen of PoAstV/PUJP5 was observed in the enterocytes of infected piglets from jejunum, ileum, colon and in inflammatory cells from mesenteric lymph nodes. In addition, villi atrophy, fusion, epithelial hyperplasia and incipient virus detection in mesenteric lymph were observed. RNAemia could not be proved. This study shows for the first time the effects of porcine astrovirus infection on conventional newly-weaning piglets.

Porcine astroviruses (PAstVs) are small RNA viruses associated with gastroenteritis. The capsid polyprotein of PAstVs, human (HAstVs) and feline (FAstVs) AstVs has a high similarity at the N-terminus before residue 415. Previous results showed the cross-detection of PAstVs and HAstVs from diarrheal samples using a commercial ELISA test that uses a monoclonal antibody to capture HAstVs, suggesting the existence of common immunoreactive epitopes between these two virus types. In this study, we seeked immunoreactive peptides located in the PAstV capsid that may be potentially used for their specific detection. The variability and hydrophobicity of a short fragment of 132 amino acids were analyzed using several capsid sequences of PAstVs and HAstVs. Peptides TATL, SLNP and IDIV were selected, synthesized and inoculated into rabbits. Pre- and hyperimmune sera were collected and their reactivity was examined by immunoassay and immunofluorescence against two wild-type strains of PAstV adapted to grow in cell culture, observing reactivity in two of the sera. Finally, the possible cross-reactivity of the sera against HAstVs was partially ruled out using HAstV8. Our data suggest that TATLGTIGSNSSGKTELEAC and IDIVVGKAATFNLKASDLSGP peptides represent immunoreactive regions useful for the specific detection of PAstVs.

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