Table Of Contents Page, PNAS Volume 109, Number 11
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Physical Sciences – Earth, Atmospheric, and Planetary Sciences
Records of micrometeorite collisions at down to submicron scales were discovered on
dust grains recovered from near-Earth asteroid 25143 (Itokawa). Because the grains
were sampled from very near the surface of the asteroid, by the Hayabusa spacecraft,
...
Social Sciences – Psychological and Cognitive Sciences – Biological Sciences – Psychological and Cognitive Sciences
Point-light biological motions, conveying various different attributes of biological
entities, have particular spatiotemporal properties that enable them to be processed
with remarkable efficiency in the human visual system. Here we demonstrate that such
...
Biological Sciences – Biochemistry
The dicistrovirus intergenic region internal ribosome entry site (IRES) utilizes a
unique mechanism, involving P-site tRNA mimicry, to directly assemble 80S ribosomes
and initiate translation at a specific non-AUG codon in the ribosomal A site. A subgroup
...
Biological Sciences – Cell Biology
Although adaptive systems of immunity against tumor initiation and destruction are
well investigated, less understood is the role, if any, of endogenous factors that
have conventional functions. Here we show that glycyl-tRNA synthetase (GRS), an essential
...
Biological Sciences – Genetics
Although the complexity and circuitry of nervous systems undergo evolutionary change,
we lack understanding of the general principles and specific mechanisms through which
it occurs. The Drosophila larval neuromuscular junction (NMJ), which has been ...
Biological Sciences – Neuroscience
To investigate the mechanistic basis for central nervous system (CNS) neurodegeneration
in the disease ataxia–telangiectasia (A-T), we analyzed flies mutant for the causative
gene A-T mutated (ATM). ATM encodes a protein kinase that functions to monitor ...
Biological Sciences – Plant Biology
The arbuscular mycorrhizal (AM) symbiosis, formed by land plants and AM fungi, evolved
an estimated 400 million years ago and has been maintained in angiosperms, gymnosperms,
pteridophytes, and some bryophytes as a strategy for enhancing phosphate ...
Physical Sciences
Applied Physical Sciences
Adding a nonadsorbing polymer to passive colloids induces an attraction between the
particles via the “depletion” mechanism. High enough polymer concentrations lead to
phase separation. We combine experiments, theory, and simulations to demonstrate that
...
Chemistry
We report the results of an in vitro screening assay targeting the intraerythrocytic
form of the malaria parasite Plasmodium falciparum using a library of 560 prenyl-synthase inhibitors. Based on “growth-rescue” and enzyme-inhibition
experiments, ...
Protein-protein interactions mediated by ubiquitin-like (Ubl) modifications occur
as mono-Ubl or poly-Ubl chains. Proteins that regulate poly-SUMO (small ubiquitin-like
modifier) chain conjugates play important roles in cellular response to DNA damage,
...
Earth, Atmospheric, and Planetary Sciences
Records of micrometeorite collisions at down to submicron scales were discovered on
dust grains recovered from near-Earth asteroid 25143 (Itokawa). Because the grains
were sampled from very near the surface of the asteroid, by the Hayabusa spacecraft,
...
Isotopes of iodine play significant environmental roles, including a limiting micronutrient
(127I), an acute radiotoxin (131I), and a geochemical tracer (129I). But the cycling of iodine through terrestrial ecosystems is poorly understood,
due to its ...
Earth’s magnetic field is sustained by magnetohydrodynamic convection within the metallic
liquid core. In a thermally advecting core, the fraction of heat available to drive
the geodynamo is reduced by heat conducted along the core geotherm, which depends
...
While the Arctic region has been warming strongly in recent decades, anomalously large
snowfall in recent winters has affected large parts of North America, Europe, and
east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is
...
This article has a correction:
Correction for Liu et al., Impact of declining Arctic sea ice on winter snowfall
How fast can a mammal evolve from the size of a mouse to the size of an elephant?
Achieving such a large transformation calls for major biological reorganization. Thus,
the speed at which this occurs has important implications for extensive faunal changes,...
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Engineering
From surface hardening of steels to doping of semiconductors, atom insertion in solids
plays an important role in modifying chemical, physical, and electronic properties
of materials for a variety of applications. High densities of atomic insertion in
a ...
A major hindrance in engineering tissues containing highly metabolically active cells
is the insufficient oxygenation of these implants, which results in dying or dysfunctional
cells in portions of the graft. The development of methods to increase oxygen ...
Social Sciences
Psychological and Cognitive Sciences
Point-light biological motions, conveying various different attributes of biological
entities, have particular spatiotemporal properties that enable them to be processed
with remarkable efficiency in the human visual system. Here we demonstrate that such
...
Seven studies using experimental and naturalistic methods reveal that upper-class
individuals behave more unethically than lower-class individuals. In studies 1 and
2, upper-class individuals were more likely to break the law while driving, relative
to ...
This article has a correction:
Correction for Piff et al., Higher social class predicts increased unethical behavior
How does one deal with unfair behaviors? This subject has long been investigated by
various disciplines including philosophy, psychology, economics, and biology. However,
our reactions to unfairness differ from one individual to another. Experimental ...
To efficiently represent all of the possible rewards in the world, dopaminergic midbrain
neurons dynamically adapt their coding range to the momentarily available rewards.
Specifically, these neurons increase their activity for an outcome that is better
...
Biological Sciences
Biochemistry
The dicistrovirus intergenic region internal ribosome entry site (IRES) utilizes a
unique mechanism, involving P-site tRNA mimicry, to directly assemble 80S ribosomes
and initiate translation at a specific non-AUG codon in the ribosomal A site. A subgroup
...
Protein-protein interactions mediated by ubiquitin-like (Ubl) modifications occur
as mono-Ubl or poly-Ubl chains. Proteins that regulate poly-SUMO (small ubiquitin-like
modifier) chain conjugates play important roles in cellular response to DNA damage,
...
The mechanisms underlying the biosynthesis of cellulose in plants are complex and
still poorly understood. A central question concerns the mechanism of microfibril
structure and how this is linked to the catalytic polymerization action of cellulose
...
The SecA ATPase associates with the SecY complex to push preproteins across the bacterial
membrane. Because a single SecY is sufficient to create the conducting channel, the
function of SecY oligomerization remains unclear. Here, we have analyzed the ...
Multimodular polyketide synthases (PKSs) have an assembly line architecture in which
a set of protein domains, known as a module, participates in one round of polyketide
chain elongation and associated chemical modifications, after which the growing chain
...
Synaptic transmission is mediated by a complex set of molecular events that must be
coordinated in time and space. While many proteins that function at the synapse have
been identified, the signaling pathways regulating these molecules are poorly ...
The rapid advance in genome sequencing presents substantial challenges for protein
functional assignment, with half or more of new protein sequences inferred from these
genomes having uncertain assignments. The assignment of enzyme function in ...
Biophysics and Computational Biology
Flagellated bacteria can swim across moist surfaces within a thin layer of fluid,
a means for surface colonization known as swarming. This fluid spreads with the swarm,
but how it does so is unclear. We used micron-sized air bubbles to study the motion
of ...
Ligands for several transcription factors can act as agonists under some conditions
and antagonists under others. The structural and molecular bases of such effects are
unknown. Previously, we demonstrated how the folding of intrinsically disordered (ID)
...
P2X receptors are trimeric ATP-gated cation channels participating in diverse physiological
processes. How ATP binding triggers channel opening remains unclear. Here the gating
mechanism of a P2X receptor was studied by normal mode analysis and molecular ...
Cell Biology
Although adaptive systems of immunity against tumor initiation and destruction are
well investigated, less understood is the role, if any, of endogenous factors that
have conventional functions. Here we show that glycyl-tRNA synthetase (GRS), an essential
...
Mammalian cells are capable of delivering multiple types of membrane capsules extracellularly.
The limiting membrane of late endosomes can fuse with the plasma membrane, leading
to the extracellular release of multivesicular bodies (MVBs), initially ...
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Mitochondrial iron levels are tightly regulated, as iron is essential for the synthesis
of Fe/S clusters and heme in the mitochondria, but high levels can cause oxidative
stress. The ATP-binding cassette (ABC) transporter ABCB8 is a mitochondrial inner
...
Many hermaphroditic organisms possess a self-incompatibility system to avoid self-fertilization.
Recently, we identified the genes responsible for self-sterility in a hermaphroditic
primitive chordate (ascidian), Ciona intestinalis: sperm-side polycystin ...
Developmental Biology
Wnts make up a large family of extracellular signaling molecules that play crucial
roles in development and disease. A subset of noncanonical Wnts signal independently
of the transcription factor β-catenin by a mechanism that regulates key morphogenetic
...
The use of assisted reproductive technologies (ART) has become increasingly common
worldwide and is now responsible for 2–3% of children born in developed countries.
Multiple reports have suggested that ART-conceived children are more likely to develop
...
Mammalian fertilization is accompanied by oscillations in egg cytoplasmic calcium
(Ca2+) concentrations that are critical for completion of egg activation. These oscillations
are initiated by Ca2+ release from inositol 1,4,5-trisphosphate (IP3)-sensitive ...
Ecology
The oceanographic conditions in the north Pacific have shifted to a colder period,
Pacific sardine (Sardinops sagax) biomass has declined precipitously in the California Current, the international
sardine fishery is collapsing, and mackerel (Trachurus ...
Shifts in the elemental stoichiometry of organisms in response to their ontogeny and
to changing environmental conditions should be related to metabolomic changes because
elements operate mostly as parts of molecular compounds. Here we show this ...
Environmental Sciences
Isotopes of iodine play significant environmental roles, including a limiting micronutrient
(127I), an acute radiotoxin (131I), and a geochemical tracer (129I). But the cycling of iodine through terrestrial ecosystems is poorly understood,
due to its ...
Evolution
How fast can a mammal evolve from the size of a mouse to the size of an elephant?
Achieving such a large transformation calls for major biological reorganization. Thus,
the speed at which this occurs has important implications for extensive faunal changes,...
View related content:
Living coyotes modify their behavior in the presence of larger carnivores, such as
wolves. However, little is known about the effects of competitor presence or absence
on morphological change in coyotes or wolves over long periods of time. We examined
the ...
Horizontal gene transfer (HGT) involves the nonsexual transmission of genetic material
across species boundaries. Although often detected in prokaryotes, examples of HGT
involving animals are relatively rare, and any evolutionary advantage conferred to
...
The gene encoding the small subunit rRNA serves as a prominent tool for the phylogenetic
analysis and classification of Bacteria and Archaea owing to its high degree of conservation and its fundamental function in living organisms.
Here we show that the ...
In most sexually reproducing animals, replication and maintenance of telomeres occurs
in the germ line and during early development in embryogenesis through the use of
telomerase. Somatic cells generally do not maintain telomere sequences, and these
cells ...
Genetics
Although the complexity and circuitry of nervous systems undergo evolutionary change,
we lack understanding of the general principles and specific mechanisms through which
it occurs. The Drosophila larval neuromuscular junction (NMJ), which has been ...
The innate immune system is an ancient and broad-spectrum defense system found in
all eukaryotes. The detection of microbial elicitors results in the up-regulation
of defense-related genes and the elicitation of inflammatory and apoptotic responses.
These ...
View related content:
Identification of immunogenic microbial patterns takes the fast lane
Myotonic dystrophy type 1 (DM1) is an RNA-dominant disease caused by abnormal transcripts
containing expanded CUG repeats. The CUG transcripts aggregate in the nucleus to form
RNA foci and lead to nuclear depletion of Muscleblind-like 1 (MBNL1) and ...
Quantitative trait loci (QTL) mapping is a powerful tool for investigating the genetic
basis of natural variation. QTL can be mapped using a number of different population
designs, but recombinant inbred lines (RILs) are among the most effective. ...
Immunology
MicroRNA-125b (miR-125b) is up-regulated in patients with leukemia. Overexpression
of miR-125b alone in mice causes a very aggressive, transplantable myeloid leukemia.
Before leukemia, these mice do not display elevation of white blood cells in the spleen
...
Type I and type II interferons (IFNs) are cytokines that establish the cellular antiviral
state through the induction of IFN-stimulated genes (ISGs). We sought to understand
the basis of the antiviral activity induced by type I and II IFNs in relation to ...
Medical Sciences
A major hindrance in engineering tissues containing highly metabolically active cells
is the insufficient oxygenation of these implants, which results in dying or dysfunctional
cells in portions of the graft. The development of methods to increase oxygen ...
Gene amplification is a tumor-specific event during malignant transformation. Recent
studies have proposed a lineage-dependency (addiction) model of human cancer whereby
amplification of certain lineage transcription factors predisposes a survival ...
Noonan syndrome (NS), a genetic disease caused in half of cases by activating mutations
of the tyrosine phosphatase SHP2 (PTPN11), is characterized by congenital cardiopathies, facial dysmorphic features, and short
stature. How mutated SHP2 induces growth ...
Hyaluronic acid (HA) has been implicated in the proliferation and metastasis of tumor
cells. However, most previous studies were conducted on extracellular matrix or pericellular
HA, and the role of circulating HA in vivo has not been studied. HA is ...
Microbiology
Influenza A virus reservoirs in animals have provided novel genetic elements leading
to the emergence of global pandemics in humans. Most influenza A viruses circulate
in waterfowl, but those that infect mammalian hosts are thought to pose the greatest
...
Ebola virus is a highly pathogenic filovirus causing severe hemorrhagic fever with
high mortality rates. It assembles heterogenous, filamentous, enveloped virus particles
containing a negative-sense, single-stranded RNA genome packaged within a helical
...
Neuroscience
To investigate the mechanistic basis for central nervous system (CNS) neurodegeneration
in the disease ataxia–telangiectasia (A-T), we analyzed flies mutant for the causative
gene A-T mutated (ATM). ATM encodes a protein kinase that functions to monitor ...
How does one deal with unfair behaviors? This subject has long been investigated by
various disciplines including philosophy, psychology, economics, and biology. However,
our reactions to unfairness differ from one individual to another. Experimental ...
To efficiently represent all of the possible rewards in the world, dopaminergic midbrain
neurons dynamically adapt their coding range to the momentarily available rewards.
Specifically, these neurons increase their activity for an outcome that is better
...
New neurons are continuously generated in the dentate gyrus (DG) in the adult hippocampus,
and new granule cells (GCs) have been shown to be necessary for several aspects of
learning and memory. Nonetheless, the limited information available regarding the
...
Axonal transport deficits have been reported in many neurodegenerative conditions
and are widely assumed to be an immediate causative step of axon and synapse loss.
By imaging changes in axonal morphology and organelle transport over time in several
...
Gamma-band synchronization adjusts the timing of excitatory and inhibitory inputs
to a neuron. Neurons in the visual cortex are selective for stimulus orientation because
of dynamic interactions between excitatory and inhibitory inputs. We hypothesized
...
The α9 and α10 cholinergic nicotinic receptor subunits assemble to form the receptor
that mediates efferent inhibition of hair cell function within the auditory sensory
organ, a mechanism thought to modulate the dynamic range of hearing. In contrast to
...
Physiology
Although protein S-nitrosylation is increasingly recognized as mediating nitric oxide (NO) signaling,
roles for protein denitrosylation in physiology remain unknown. Here, we show that
S-nitrosoglutathione reductase (GSNOR), an enzyme that governs levels ...
Fructose intake from added sugars correlates with the epidemic rise in obesity, metabolic
syndrome, and nonalcoholic fatty liver disease. Fructose intake also causes features
of metabolic syndrome in laboratory animals and humans. The first enzyme in ...
Psychological and Cognitive Sciences
Point-light biological motions, conveying various different attributes of biological
entities, have particular spatiotemporal properties that enable them to be processed
with remarkable efficiency in the human visual system. Here we demonstrate that such
...
Sustainability Science
Time to flowering has an important impact on yield and has been a key trait in the
domestication of crop plants and the spread of agriculture. In 1961, the cultivar
Mari (mat-a.8) was the very first induced early barley (Hordeum vulgare L.) mutant to be ...
Correction
Cover image: Pictured is an African elephant, the world’s largest extant land mammal. Alistair R. Evans et al. developed a metric to quantify the rates of body size evolution of mammals during the last 70 million years. The authors estimate that the transition from a mouse-sized to an elephant-sized animal would take at least 24 million generations. The findings illustrate the comparative difficulty of major transformations in body size. See the article by Evans et al. on pages 4187–4190. Image courtesy of Daniel P. Costa.
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