Multiple introductions and onward transmission of non-pandemic HIV-1 subtype B strains in North America and Europe

Most HIV-1 subtype B infections in North America and Europe seem to have resulted from the expansion of a single pandemic lineage (B PANDEMIC) disseminated from the United States (US). Some non-pandemic subtype B strains of Caribbean origin (B CAR) may have also reached North America and Europe, but their epidemiological relevance in those regions remains largely unknown. Here we analyze a total of 20,045 HIV-1 subtype B pol sequences from the US, Canada, and Europe, to estimate the prevalence and to reconstruct the spatiotemporal dynamics of dissemination of HIV-1 B CAR strains in those regions. We find that B CAR strains were probably disseminated from the Caribbean into North America and Europe at multiple times since the early 1970s onwards. The B CAR strains reached the US, Canada and at least 16 different European countries, where they account for a very low fraction (<5%) of subtype B infections, with exception of the Czech Republic (7.7%). We also find evidence of the onward transmission of B CAR clades in the US, Canada, the Czech Republic, Germany, Italy, Spain and the UK, as well as short-distance spreading of B CAR lineages between neighboring European countries from Central and Western Europe, and long-distance dissemination between the US and Europe

Detection of integron integrase genes on King George Island, Antarctica

The presence and diversity of class 1 integrase gene (intI) sequences were evaluated by PCR using previously designed primers. Two clone libraries were constructed from DNA in sediment and microbial mat samples collected on Fildes Peninsula, King George Island, Antarctica.The libraries constructed from samples collected at Halfthree Point (HP) and Norma Cove (NC) contained 62 and 36 partial intI sequences, respectively. These sequences clustered into 10 different groups with <95% amino acid identity. Alignment of the deduced amino acid sequences with those from recognized integron-encoded integrases demonstrated the presence of highly conserved motifs characteristic of intI integrases. The HP library contained 42 nucleotide sequences identical to the class 1 intI gene found in a collection of trimethoprim-resistant (Tmpr) Antarctic Enterobacter sp. isolates, previously collected in the same area. These integrons, located on plasmids, had a genetic organization similar to that of pKOX105 from Klebsiella oxytoca. The 20 remaining HP and NC library sequences were similar to integrase sequences previously determined in a metagenomic analysis of environmental samples. We have demonstrated the presence of integron integrase genes in Antarctic sediment samples. About half these genes were very similar to the class 1 integrons found in humanassociated microbiota, suggesting that they originated from human-dominated ecosystems. The remaining integrase genes were probably associated with endemic bacteria

Arabidopsis HAP2/GCS1 is a gamete fusion protein homologous to somatic and viral fusogens

Cell–cell fusion is inherent to sexual reproduction. Loss of HAPLESS 2/GENERATIVE CELL SPECIFIC 1 (HAP2/GCS1) proteins results in gamete fusion failure in diverse organisms, but their exact role is unclear. In this study, we show that Arabidopsis thaliana HAP2/GCS1 is sufficient to promote mammalian cell–cell fusion. Hemifusion and complete fusion depend on HAP2/GCS1 presence in both fusing cells. Furthermore, expression of HAP2 on the surface of pseudotyped vesicular stomatitis virus results in homotypic virus–cell fusion. We demonstrate that the Caenorhabditis elegans Epithelial Fusion Failure 1 (EFF-1) somatic cell fusogen can replace HAP2/GCS1 in one of the fusing membranes, indicating that HAP2/GCS1 and EFF-1 share a similar fusion mechanism. Structural modeling of the HAP2/GCS1 protein family predicts that they are homologous to EFF-1 and viral class II fusion proteins (e.g., Zika virus). We name this superfamily Fusexins: fusion proteins essential for sexual reproduction and exoplasmic merger of plasma membranes. We suggest a common origin and evolution of sexual reproduction, enveloped virus entry into cells, and somatic cell fusion

Predominant methanogenic metabolism in a UASB digester fed with vinasse in Tucumán, Argentina

Los efluentes líquidos producidos por las destilerías de alcohol asociadas a ingenios azucareros en el Noroeste argentino son una fuente de contaminación si son vertidas en forma inadecuada en las cuencas hídricas. La generación de efluentes de este tipo crece con la demanda de bioetanol tanto en Argentina como en el mundo. En la depuración de los mismos, los reactores de tipo UASB son una solución integral dado que agregan el valor de la producción biogás. Por medio del secuenciado de fragmentos ribosomales del metagenoma de un reactor de tipo UASB a escala piloto (200 L), analizamos la comunidad de archaeas del mismo. Este estudio pretende contribuir a la determinación de las condiciones operativas de funcionamiento del digestor para maxiumizar la depuración de la carga orgánica de los efluentes y la generación asociada de biogás. La metodología incluyó extracción del metagenoma, su amplificación por medio de primers universales para procariotas dirigidos al dominio V4 del gen 16SrDNA y su posterior secuenciado usando la tecnología de pirosecuenciado. Nuestros resultados indican que en el digestor alimentado con vinazas estudiado, la metanogénesis se debe a la combinación de metabolismos hidrogenotrópico y acetogénico. Dado que los estudios de rarefracción indicaron una cobertura de la diversidad insuficiente, se realizan nuevos análisis con cambios en los protocolos de extracción y purificación de ADN y en las estrategias de secuenciado. Con relación a Eubacteria, resultó llamativa la proporción de Verrucomicrobiales, cercana al 18%. Esta proporción de metanótrofos puede indicar irregularidades en el mantenimiento del régimen del digestor. Estudios sobre este grupo bacteriano en particular podrían usarse como parámetro de eficiencia en el mantenimiento del consorcio microbiano.Asociación de Universidades Grupo Montevide