A "semi-closed" recirculating system for the in situ study of feeding and respiration of benthic suspension feeders

Suspension feeding is one of the most widespread feeding strategies among benthic organisms. However, natural feeding ecology and energetics of benthic suspension feeders are poorly known. The scarcity of field methods, apparatus and protocols that facilitate obtention of reliable in situ data has contributed to this lack of knowledge. A detailed description of an improved semi-closed recirculating system as well as the experimental set up is provided for the study of energetics in benthic suspension feeders. The system, completely submersible and surface-independent, allows us to assess oxygen concentration changes and feeding rates under natural conditions. Methodological examinations are conducted to investigate: a) the circulation of the water within the chamber; b) the time required for the flushing pump to entirely renew the volume of water of the incubation chambers; c) the behavior of the species within the chambers; d) the time of acclimation to the chamber conditions for the different species; e) the maximum decrease in oxygen concentration without affecting respiration rate; f) the time required to detect changes in concentration of the natural food sources. The system and experimental protocol is tested with species from three representative phyla, Porifera, Cnidaria and TunicataThe manuscript was improved by the comments of Fenny Cox. We would like to thanks the assistance of Mikel Zabala, Josep-Maria Llenas and Loïc de Maissonneuve. Support for this work was provided by a RED research contract from the “Generalitat de Catalunya” to R.C., by a postdoctoral fellowship from the “Ministerio de Educación y Cultura” to M.R., by PETRI grant PTR94-0119, by DGICYT grant PB98-0456-C03-01 and by a LEA projectPeer reviewe

Low nadir CD4+ T-cell counts predict gut dysbiosis in HIV-1 infection

Human immunodeficiency virus (HIV)-1 infection causes severe gut and systemic immune damage, but its effects on the gut microbiome remain unclear. Previous shotgun metagenomic studies in HIV-negative subjects linked low-microbial gene counts (LGC) to gut dysbiosis in diseases featuring intestinal inflammation. Using a similar approach in 156 subjects with different HIV-1 phenotypes, we found a strong, independent, dose-effect association between nadir CD4+ T-cell counts and LGC. As in other diseases involving intestinal inflammation, the gut microbiomes of subjects with LGC were enriched in gram-negative Bacteroides, acetogenic bacteria and Proteobacteria, which are able to metabolize reactive oxygen and nitrogen species; and were depleted in oxygen-sensitive methanogenic archaea and sulfate-reducing bacteria. Interestingly, subjects with LGC also showed increased butyrate levels in direct fecal measurements, consistent with enrichment in Roseburia intestinalis despite reductions in other butyrate producers. The microbiomes of subjects with LGC were also enriched in bacterial virulence factors, as well as in genes associated with beta-lactam, lincosamide, tetracycline, and macrolide resistance. Thus, low nadir CD4+ T-cell counts, rather than HIV-1 serostatus per se, predict the presence of gut dysbiosis in HIV-1 infected subjects. Such dysbiosis does not display obvious HIV-specific features; instead, it shares many similarities with other diseases featuring gut inflammation.Fundació Glòria SolerFundació Catalunya-La PedreraGala SIDA 2015-2016Nit per la Recerca a la Catalunya Central 2015 editionPeople in Red-Barcelona 2016 editionRED de SIDA RD16/0025/0041ISCIIIEuropean Regional Develpment Fund (ERDF)Agencia de Gestio d´Ajuts Universitaris i de Recerca (AGAUR)Secretaria d´Universitats i Recerca del Departament d´Economia i Coneixement de la Generalitat de CatalunyaMinisterio de Economia y Competitividad. EspañaUniversidad de Whashingto

Low nadir CD4+ T-cell counts predict gut dysbiosis in HIV-1 infection

Human immunodeficiency virus (HIV)-1 infection causes severe gut and systemic immune damage, but its effects on the gut microbiome remain unclear. Previous shotgun metagenomic studies in HIV-negative subjects linked low-microbial gene counts (LGC) to gut dysbiosis in diseases featuring intestinal inflammation. Using a similar approach in 156 subjects with different HIV-1 phenotypes, we found a strong, independent, dose-effect association between nadir CD4+ T-cell counts and LGC. As in other diseases involving intestinal inflammation, the gut microbiomes of subjects with LGC were enriched in gram-negative Bacteroides, acetogenic bacteria and Proteobacteria, which are able to metabolize reactive oxygen and nitrogen species; and were depleted in oxygen-sensitive methanogenic archaea and sulfate-reducing bacteria. Interestingly, subjects with LGC also showed increased butyrate levels in direct fecal measurements, consistent with enrichment in Roseburia intestinalis despite reductions in other butyrate producers. The microbiomes of subjects with LGC were also enriched in bacterial virulence factors, as well as in genes associated with beta-lactam, lincosamide, tetracycline, and macrolide resistance. Thus, low nadir CD4+ T-cell counts, rather than HIV-1 serostatus per se, predict the presence of gut dysbiosis in HIV-1 infected subjects. Such dysbiosis does not display obvious HIV-specific features; instead, it shares many similarities with other diseases featuring gut inflammation

A "semi-closed" recirculating system for the in situ study of feeding and respiration of benthic suspension feeders

Suspension feeding is one of the most widespread feeding strategies among benthic organisms. However, natural feeding ecology and energetics of benthic suspension feeders are poorly known. The scarcity of field methods, apparatus and protocols that facilitate obtention of reliable in situ data has contributed to this lack of knowledge. A detailed description of an improved semi-closed recirculating system as well as the experimental set up is provided for the study of energetics in benthic suspension feeders. The system, completely submersible and surface-independent, allows us to assess oxygen concentration changes and feeding rates under natural conditions. Methodological examinations are conducted to investigate: a) the circulation of the water within the chamber; b) the time required for the flushing pump to entirely renew the volume of water of the incubation chambers; c) the behavior of the species within the chambers; d) the time of acclimation to the chamber conditions for the different species; e) the maximum decrease in oxygen concentration without affecting respiration rate; f) the time required to detect changes in concentration of the natural food sources. The system and experimental protocol is tested with species from three representative phyla, Porifera, Cnidaria and TunicataThe manuscript was improved by the comments of Fenny Cox. We would like to thanks the assistance of Mikel Zabala, Josep-Maria Llenas and Loïc de Maissonneuve. Support for this work was provided by a RED research contract from the “Generalitat de Catalunya” to R.C., by a postdoctoral fellowship from the “Ministerio de Educación y Cultura” to M.R., by PETRI grant PTR94-0119, by DGICYT grant PB98-0456-C03-01 and by a LEA projectPeer reviewe

Characterization of the spatial distribution of RMS delay spread in indoor LOS wireless environments at 5.2GHz

SIGLEAvailable from British Library Document Supply Centre-DSC:4335.26205(98-161) / BLDSC - British Library Document Supply CentreGBUnited Kingdo