An analysis of bacterial community structure and antibiotic resistance gene content of interconnected human faecal and environmental samples from two low-income communities in Latin America was carried out using a combination of functional metagenomics, 16S sequencing and shotgun sequencing; resistomes across habitats are generally structured along ecological gradients, but key resistance genes can cross these boundaries, and the authors assessed the usefulness of excreta management protocols in the prevention of resistance gene dissemination.
The health emergency precipitated by the Zika virus is a salutary reminder: global preparedness for emerging pathogens with endemic or pandemic potential is crucial and needs an overhaul. These crises are not rare — Lassa fever, Ebola virus, Middle East respiratory syndrome, H1N1 influenza and severe acute respiratory syndrome (SARS) have surfaced in head-spinning succession over the past 10–15 years. Each emergence proves how woefully unprepared the global community is to deal with worldwide health emergencies that have deep societal and economic impact.
Implantation of the blastocyst is a developmental milestone in mammalian embryonic development. At this time, a coordinated program of lineage diversification, cell-fate specification, and morphogenetic movements establishes the generation of extra-embryonic tissues and the embryo proper, and determines the conditions for successful pregnancy and gastrulation. Despite its basic and clinical importance, this process remains mysterious in humans. Here we report the use of a novel in vitro system to study the post-implantation development of the human embryo.
Nitrogen oxides are essential for the formation of secondary atmospheric aerosols and of atmospheric oxidants such as ozone and the hydroxyl radical, which controls the self-cleansing capacity of the atmosphere. Nitric acid, a major oxidation product of nitrogen oxides, has traditionally been considered to be a permanent sink of nitrogen oxides1. However, model studies predict higher ratios of nitric acid to nitrogen oxides in the troposphere than are observed.
The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized.
On 26 April, a team led by microbial population geneticist Daniel Croll, who is at the Swiss Federal Institute of Technology in Zurich, reported on github.com that the Bangladeshi wheat-blast strain is closely related to those collected in Brazilian wheat fields and on nearby weeds. His team’s analysis, which uses the data on the website Open Wheat Blast, reveals that the sample is not closely related to known rice-blast-causing strains of M. oryzae.
New excavations in Liang Bua, where the remains of the ‘Hobbit’ (Homo floresiensis) were discovered, show that this diminutive human species used this cave between 190,000 and 50,000 years ago, and not until as recently as 12,000 years ago as previously interpreted; modern humans have been present in Australia since around 50,000 years ago, so whether Homo floresiensis survived long enough to witness the arrival of modern humans is still an open question.
A tremor source on the San Andreas Fault produced an unusual sequence of low-frequency earthquakes until it was disrupted by the 2004 Parkfield earthquake; the peculiar recurrence pattern has now been modelled, showing that such slip behaviour occurs when the tremor asperity size is close to the critical nucleation size of earthquakes.
