Feed aggregator

Reconstruction and evolutionary history of eutherian chromosomes [Evolution]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Whole-genome assemblies of 19 placental mammals and two outgroup species were used to reconstruct the order and orientation of syntenic fragments in chromosomes of the eutherian ancestor and six other descendant ancestors leading to human. For ancestral chromosome reconstructions, we developed an algorithm (DESCHRAMBLER) that probabilistically determines the adjacencies of...

Chimpanzees return favors at a personal cost [Psychological and Cognitive Sciences]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Humans regularly provide others with resources at a personal cost to themselves. Chimpanzees engage in some cooperative behaviors in the wild as well, but their motivational underpinnings are unclear. In three experiments, chimpanzees (Pan troglodytes) always chose between an option delivering food both to themselves and a partner and one...

{Delta}20 IFITM2 differentially restricts X4 and R5 HIV-1 [Microbiology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
CCR5 (R5)-tropic, but not CXCR4 (X4)-tropic, HIV-1 is associated with primary HIV-1 infection and transmission. Recent studies have shown that IFN-induced transmembrane (IFITM) proteins, including IFITM1, IFITM2, and IFITM3, restrict a broad range of viruses. Here, we demonstrate that an IFITM2 isoform (Δ20 IFITM2) lacking 20 amino acids at the...

How selective severing by katanin promotes order in the plant cortical microtubule array [Plant Biology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Plant morphogenesis requires differential and often asymmetric growth. A key role in controlling anisotropic expansion of individual cells is played by the cortical microtubule array. Although highly organized, the array can nevertheless rapidly change in response to internal and external cues. Experiments have identified the microtubule-severing enzyme katanin as a...

TCTE1 is a conserved component of the dynein regulatory complex and is required for motility and metabolism in mouse spermatozoa [Developmental Biology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Flagella and cilia are critical cellular organelles that provide a means for cells to sense and progress through their environment. The central component of flagella and cilia is the axoneme, which comprises the “9+2” microtubule arrangement, dynein arms, radial spokes, and the nexin-dynein regulatory complex (N-DRC). Failure to properly assemble...

Correction to Supporting Information for Suzuki et al., Behavioral contagion during learning about another agent’s risk-preferences acts on the neural representation of decision-risk [SI Correction]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
PSYCHOLOGICAL AND COGNITIVE SCIENCES, NEUROSCIENCE Correction to Supporting Information for “Behavioral contagion during learning about another agent’s risk-preferences acts on the neural representation of decision-risk,” by Shinsuke Suzuki, Emily L. S. Jensen, Peter Bossaerts, and John P. O’Doherty, which appeared in issue 14, April 5, 2016, of Proc Natl Acad...

Correction for Koch et al., Genetic rescue models refute nonautonomous rod cell death in retinitis pigmentosa [Corrections]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
NEUROSCIENCE Correction for “Genetic rescue models refute nonautonomous rod cell death in retinitis pigmentosa,” by Susanne F. Koch, Jimmy K. Duong, Chun-Wei Hsu, Yi-Ting Tsai, Chyuan-Sheng Lin, Christian A. Wahl-Schott, and Stephen H. Tsang, which appeared in issue 20, May 16, 2017, of Proc Natl Acad Sci USA (114:5259–5264; first...

Targeting reactive nitrogen species suppresses hereditary pancreatic cancer [Medical Sciences]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Germline mutation of BRCA2 induces hereditary pancreatic cancer. However, how BRCA2 mutation specifically induces pancreatic tumorigenesis remains elusive. Here, we have examined a mouse model of Brca2-deficiency–induced pancreatic tumors and found that excessive reactive nitrogen species (RNS), such as nitrite, are generated in precancerous pancreases, which induce massive DNA damage,...

Robert Treat Paine III (1933-2016) [Retrospectives]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Robert Treat Paine III passed away June 13 in Seattle surrounded by family and friends. RTP, as he was known, was an emeritus Professor at the University of Washington, where he developed a career that helped define the field of community ecology. Ever an avid naturalist who paid close attention...

Recombinant silicateins as model biocatalysts in organosiloxane chemistry [Chemistry]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
The family of silicatein enzymes from marine sponges (phylum Porifera) is unique in nature for catalyzing the formation of inorganic silica structures, which the organisms incorporate into their skeleton. However, the synthesis of organosiloxanes catalyzed by these enzymes has thus far remained largely unexplored. To investigate the reactivity of these...

Reducing secondary organic aerosol formation from gasoline vehicle exhaust [Environmental Sciences]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This...

QnAs with Tony Hunter and James Allison [QnAs]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
In the mid-1990s, the miracle drug Gleevec revolutionized cancer treatment, offering terminally ill patients with chronic myeloid leukemia (CML) a new lease on life. Until then, the only weapons in the medical arsenal against cancer were the blunt and brutal triad of surgery, radiation, and conventional chemotherapy. Gleevec, which ushered...

Group augmentation, collective action, and territorial boundary patrols by male chimpanzees [Anthropology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
How can collective action evolve when individuals benefit from cooperation regardless of whether they pay its participation costs? According to one influential perspective, collective action problems are common, especially when groups are large, but may be solved when individuals who have more to gain from the collective good or can...

A prokaryotic viral sequence is expressed and conserved in mammalian brain [Microbiology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
A natural and permanent transfer of prokaryotic viral sequences to mammals has not been reported by others. Circular “SPHINX” DNAs <5 kb were previously isolated from nuclease-protected cytoplasmic particles in rodent neuronal cell lines and brain. Two of these DNAs were sequenced after Φ29 polymerase amplification, and they revealed significant...

Uncovering BRD4 hyperphosphorylation associated with cellular transformation in NUT midline carcinoma [Cell Biology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
The epigenetic reader BRD4 plays a vital role in transcriptional regulation, cellular growth control, and cell-cycle progression. Dysregulation of BRD4 function has been implicated in the pathogenesis of a wide range of cancers. However, how BRD4 is regulated to maintain its normal function in healthy cells and how alteration of...

Transitional-turbulent spots and turbulent-turbulent spots in boundary layers [Engineering]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional–turbulent spot inception mechanism is analogous to the secondary...

Multiple layers of heterogeneity and subset diversity in human MAIT cell responses to distinct microorganisms and to innate cytokines [Immunology and Inflammation]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
Mucosa-associated invariant T (MAIT) cells are a large innate-like T-cell subset in humans defined by invariant TCR Vα7.2 use and expression of CD161. MAIT cells recognize microbial riboflavin metabolites of bacterial or fungal origin presented by the monomorphic MR1 molecule. The extraordinary level of evolutionary conservation of MR1 and the...

Heat exchange between a bouncing drop and a superhydrophobic substrate [Ecology]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
The ability to enhance or limit heat transfer between a surface and impacting drops is important in applications ranging from industrial spray cooling to the thermal regulation of animals in cold rain. When these surfaces are micro/nanotextured and hydrophobic, or superhydrophobic, an impacting drop can spread and recoil over trapped...

Nanophotonics-enabled solar membrane distillation for off-grid water purification [Applied Physical Sciences]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
With more than a billion people lacking accessible drinking water, there is a critical need to convert nonpotable sources such as seawater to water suitable for human use. However, energy requirements of desalination plants account for half their operating costs, so alternative, lower energy approaches are equally critical. Membrane distillation...

Measuring shared variants in cohorts of discordant siblings with applications to autism [Genetics]

PNAS Early Edition Articles - Mon, 06/19/2017 - 13:48
We develop a method of analysis [affected to discordant sibling pairs (A2DS)] that tests if shared variants contribute to a disorder. Using a standard measure of genetic relation, test individuals are compared with a cohort of discordant sibling pairs (CDS) to derive a comparative similarity score. We ask if a...
Syndicate content