Metagenomic survey for viruses in Western Arctic caribou, Alaska, through iterative assembly of taxonomic units

Pathogen surveillance in animals does not provide a sufficient level of vigilance because it is generally confined to surveillance of pathogens with known economic impact in domestic animals and practically nonexistent in wildlife species. As most (re-)emerging viral infections originate from animal sources, it is important to obtain insight into viral pathogens present in the wildlife reservoir from a public health perspective. When monitoring living, free-ranging wildlife for viruses, sample collection can be challenging and availability of nucleic acids isolated from samples is often limited. The development of viral metagenomics platforms allows a more comprehensive

Procyclin Null Mutants of Trypanosoma brucei Express Free Glycosylphosphatidylinositols on Their Surface

Procyclins are abundant, glycosylphosphatidylinositol (GPI)-anchored proteins on the surface of procyclic (insect) form trypanosomes. To investigate whether trypanosomes are able to survive without a procyclin coat, all four procyclin genes were deleted sequentially. Bloodstream forms of the null mutant exhibited no detectable phenotype and were able to differentiate to procyclic forms. Initially, differentiated null mutant cells were barely able to grow, but after an adaptation period of 2 mo in culture they proliferated at the same rate as wild-type trypanosomes. Analysis of these culture-adapted null mutants revealed that they were covered by free GPIs. These were closely related to the mature procyclin anchor in structure and were expressed on the surface in numbers comparable with that of procyclin in wild-type cells. However, free GPIs were smaller than the procyclin anchor, indicative of a lower number of poly-N-acetyllactosamine repeats, and a proportion contained diacylphosphatidic acid. Free GPIs are also expressed by wild-type cells, although to a lesser extent. These have been overlooked in the past because they partition in a solvent fraction (chloroform/water/methanol) that is normally discarded when GPI-anchored proteins are purified