Volume 525 Issue 7568


Money matters p.157

It is not how much people have, it is how much we know they have that stokes inequality.

doi: 10.1038/525157b

Keep a welcome p.157

The plight of a record number of refugees is something the West cannot ignore. Humanitarian values should be upheld, and people fleeing war and persecution must be offered protection.

doi: 10.1038/525157a

Loaded language p.158

There can be more to a question than appears at first sight.

doi: 10.1038/525158a


News Features

News & Views

Simple market models fail the test p.190

An analysis of energy markets with prices that vary according to demand finds that this market design unexpectedly serves to amplify, rather than dampen, fluctuations in power use.

doi: 10.1038/nature15215

Countercurrents in lipid flow p.191

Two studies find that a lipid-exchange cycle mediates the enrichment of the lipid phosphatidylserine in the cell membrane compared with the membrane of an organelle called the endoplasmic reticulum, where the lipid is produced.

doi: 10.1038/525191a

Amyloid-β pathology induced in humans p.193

People who died of the neurodegenerative condition Creutzfeldt-Jakob disease after treatment with cadaver-derived human growth hormone also developed some of the pathological traits of Alzheimer's disease. See Letter p.247

doi: 10.1038/525193a

Sea-spray particles cause freezing in clouds p.194

Ice clouds in marine regions at high latitudes might form in warmer and drier air than was previously believed because of freezing induced by airborne particles that contain organic materials from ocean surface waters. See Letter p.234

doi: 10.1038/525194a

Glimpse into a primitive stellar nursery p.195

The first well-resolved images of local-galaxy stellar nurseries that are poor in elements heavier than helium give the best picture yet of the conditions in which stars may have formed in the early Universe. See Letter p.218

doi: 10.1038/525195a

How to catch rare cell types p.197

The development of an algorithm called RaceID enables the identification of rare cell types by single-cell RNA sequencing, even when they are part of a complex mixture of similar cells. See Letter p.251

doi: 10.1038/nature15204

A moving target p.198

An in silico, three-dimensional model of tumour evolution suggests that cell motility is a key factor in the initial growth of a tumour mass. The model also reveals the dynamics of mutation spread. See Letter p.261

doi: 10.1038/nature15210

Mutant p53 and chromatin regulation p.199

The finding that genes encoding enzymes that modify histone proteins are among the targets of certain mutant forms of the p53 protein sheds light on how these mutations cause cancer beyond p53 inactivation. See Article p.206

doi: 10.1038/nature15212


Mapping tree density at a global scale p.201

Ground-sourced tree density data is assembled to provide a global map of tree density, which reveals that there are three trillion trees (tenfold more than previous estimates); tree numbers have declined by nearly half since the start of human civilization and over 15 billion trees are lost on an annual basis.

doi: 10.1038/nature14967

Gain-of-function p53 mutants co-opt chromatin pathways to drive cancer growth p.206

A ChIP-seq analysis of the DNA-binding properties of mutant gain-of-function p53 protein compared to wild-type p53 reveals the gain-of-function proteins bind to and activate a distinct set of genes including chromatin modifying enzymes such as the histone methyltransferase MLL; small molecular inhibitors of MLL function may represent a new target for cancers with mutant p53.

doi: 10.1038/nature15251


Quadrature squeezed photons from a two-level system p.222

Measurements of a steady emission of single photons from a quantum dot demonstrate that the fluctuations of the electric field can periodically be 3% below the fundamental quantum limit and confirm the long-standing prediction that the quantum state of single photons can be squeezed.

doi: 10.1038/nature14868

Computational design of co-assembling protein–DNA nanowires p.230

Computational protein design is used to create a protein–DNA co-assembling nanomaterial; by varying the arrangement of protein-binding sites on the double-stranded DNA, a ‘nanowire’ with single-molecule width can be spontaneously formed by mixing the protein and double-stranded DNA building blocks.

doi: 10.1038/nature14874

A marine biogenic source of atmospheric ice-nucleating particles p.234

The presence of ice in clouds can influence cloud lifetime, precipitation and radiative properties; here, organic material at the sea–air interface, possibly associated with phytoplankton cell exudates, is shown to nucleate ice under conditions relevant for ice cloud formation in the atmospheric environment.

doi: 10.1038/nature14986

Evolutionary origin of the turtle skull p.239

Computed tomography and phylogenetic analysis of the Eunotosaurus africanus skull suggests that not only is Eunotosaurus an early relative of the group that eventually evolved into turtles, but that it is also a diapsid caught in the act of evolving towards a secondarily anapsid state.

doi: 10.1038/nature14900

Evidence for human transmission of amyloid-β pathology and cerebral amyloid angiopathy p.247

More than two hundred individuals developed Creutzfeldt–Jakob disease (CJD) worldwide as a result of treatment, typically in childhood, with human cadaveric pituitary-derived growth hormone contaminated with prions. Although such treatment ceased in 1985, iatrogenic CJD (iCJD) continues to emerge because of the prolonged incubation periods seen in human prion infections. Unexpectedly, in an autopsy study of eight individuals with iCJD, aged 36–51 years, in four we found moderate to severe grey matter and vascular amyloid-β (Aβ) pathology. The Aβ deposition in the grey matter was typical of that seen in Alzheimer’s disease and Aβ in the blood vessel walls was characteristic of cerebral amyloid angiopathy and did not co-localize with prion protein deposition. None of these patients had pathogenic mutations, APOE ε4 or other high-risk alleles associated with early-onset Alzheimer’s disease. Examination of a series of 116 patients with other prion diseases from a prospective observational cohort study showed minimal or no Aβ pathology in cases of similar age range, or a decade older, without APOE ε4 risk alleles. We also analysed pituitary glands from individuals with Aβ pathology and found marked Aβ deposition in multiple cases. Experimental seeding of Aβ pathology has been previously demonstrated in primates and transgenic mice by central nervous system or peripheral inoculation with Alzheimer’s disease brain homogenate. The marked deposition of parenchymal and vascular Aβ in these relatively young patients with iCJD, in contrast with other prion disease patients and population controls, is consistent with iatrogenic transmission of Aβ pathology in addition to CJD and suggests that healthy exposed individuals may also be at risk of iatrogenic Alzheimer’s disease and cerebral amyloid angiopathy. These findings should also prompt investigation of whether other known iatrogenic routes of prion transmission may also be relevant to Aβ and other proteopathic seeds associated with neurodegenerative and other human diseases.

doi: 10.1038/nature15369

Single-cell messenger RNA sequencing reveals rare intestinal cell types p.251

An algorithm that allows rare cell type identification in a complex population of single cells, based on single-cell mRNA-sequencing, is applied to mouse intestinal cells, revealing novel subtypes of enteroendocrine cells and showing that the Lgr5-expressing population consists of a homogenous stem cell population with a few rare secretory cells, including Paneth cells.

doi: 10.1038/nature14966

Distinct EMT programs control normal mammary stem cells and tumour-initiating cells p.256

This study finds that the epithelial-to-mesenchymal (EMT) transition program, which is common to both mammary gland reconstituting stem cells and mammary tumour-initiating cells, is differentially regulated by two distinct EMT factors, Slug and Snail; the findings illustrate that although they appear similar, normal tissue stem cells and tumour-initiating cells are controlled by distinct regulatory processes.

doi: 10.1038/nature14897

Real-time observation of the initiation of RNA polymerase II transcription p.274

A single-molecule optical tweezer assay is developed to monitor transcription initiation in eukaryotic RNA polymerase II in real-time, making use of a highly purified preinitiation complex (PIC) from yeast; observations show that a large bubble is opened up in the DNA template during initiation, driven by the TFIIH helicase that forms part of the PIC, along with synthesis of an extended transcript before the transition from transcription initiation into elongation.

doi: 10.1038/nature14882