Table Of Contents Page, PNAS Volume 121, Number 28
This Week in PNAS
Opinion
Retrospective
Commentaries
Perspective
Vat photopolymerization (VP) additive manufacturing enables fabrication of complex
3D objects by using light to selectively cure a liquid resin. Developed in the 1980s,
this technique initially had few practical applications due to limitations in print
...
Letter
Brief Reports
While the intracellular–extracellular distribution of lactate has been suggested to
play a critical role in the healthy and diseased brain, tools are lacking to noninvasively
probe lactate in intracellular and extracellular spaces. Here, we show that, by ...
Mitigating greenhouse gas emissions and reducing air pollution represent two pressing
and interwoven environmental challenges. While international carbon markets, such
as the European Union emissions trading system (EU ETS), have demonstrated their ...
Cycling cells replicate their DNA during the S phase through a defined temporal program
known as replication timing. Mutation frequencies, epigenetic chromatin states, and
transcriptional activities are different for genomic regions that are replicated ...
DNA polymerase κ (Polκ) is a specialized polymerase that has multiple cellular roles
such as translesion DNA synthesis, replication of repetitive sequences, and nucleotide
excision repair. We have developed a method for capturing DNA synthesized by Polκ
...
Physical Sciences
Applied Mathematics
Humans and animals routinely infer relations between different items or events and
generalize these relations to novel combinations of items. This allows them to respond
appropriately to radically novel circumstances and is fundamental to advanced ...
Applied Physical Sciences
Mesenchymal stem cells (MSCs) are essential in regenerative medicine. However, conventional
expansion and harvesting methods often fail to maintain the essential extracellular
matrix (ECM) components, which are crucial for their functionality and efficacy ...
Despite the ubiquity of thermal convection in nature and artificial systems, we still
lack a unified formulation that integrates the system’s geometry, fluid properties,
and thermal forcing to characterize the transition from free to confined convective
...
Mineral precipitation caused by fluid mixing presents complex control and predictability
challenges in a variety of natural and engineering processes, including carbon mineralization,
geothermal energy, and microfluidics. Precipitation dynamics, ...
Complex systems are characterized by emergent patterns created by the nontrivial interplay
between dynamical processes and the networks of interactions on which these processes
unfold. Topological or dynamical descriptors alone are not enough to fully ...
Iron antimonide (FeSb2) has been investigated for decades due to its puzzling electronic properties. It
undergoes the temperature-controlled transition from an insulator to an ill-defined
metal, with a cross-over from diamagnetism to paramagnetism. ...
Liquid-phase electron microscopy (LP-EM) imaging has revolutionized our understanding
of nanosynthesis and assembly. However, the current closed geometry limits its application
for open systems. The ubiquitous physical process of the coffee-ring ...
Biophysics and Computational Biology
An array of motor proteins consumes chemical energy in setting up the architectures
of chromosomes. Here, we explore how the structure of ideal polymer chains is influenced
by two classes of motors. The first class which we call “swimming motors” acts to
...
Transcription has a mechanical component, as the translocation of the transcription
machinery or RNA polymerase (RNAP) on DNA or chromatin is dynamically coupled to the
chromatin torsion. This posits chromatin mechanics as a possible regulator of ...
Tissue buckling is an increasingly appreciated mode of morphogenesis in the embryo,
but it is often unclear how geometric and material parameters are molecularly determined
in native developmental contexts to generate diverse functional patterns. Here, we
...
Only 30% of embryos from in vitro fertilized oocytes successfully implant and develop
to term, leading to repeated transfer cycles. To reduce time-to-pregnancy and stress
for patients, there is a need for a diagnostic tool to better select embryos and ...
Chemistry
Iron is an essential element for life owing to its ability to participate in a diverse
array of oxidation–reduction reactions. However, misregulation of iron-dependent redox
cycling can also produce oxidative stress, contributing to cell growth, ...
MXenes have demonstrated potential for various applications owing to their tunable
surface chemistry and metallic conductivity. However, high temperatures can accelerate
MXene film oxidation in air. Understanding the mechanisms of MXene oxidation at ...
Nanomaterials acquire a biomolecular corona upon introduction to biological media,
leading to biological transformations such as changes in protein function, unmasking
of epitopes, and protein fibrilization. Ex vivo studies to investigate the effect
of ...
Earth, Atmospheric, and Planetary Sciences
Solar particle events (SPEs) are short-lived bursts of high-energy particles from
the solar atmosphere and are widely recognized as posing significant economic risks
to modern society. Most SPEs are relatively weak and have minor impacts on the Earth’s
...
Variable viscosity in Earth’s mantle exerts a fundamental control on mantle convection
and plate tectonics, yet rigorously constraining the underlying parameters has remained
a challenge. Inverse methods have not been sufficiently robust to handle the ...
Engineering
Currently, the nanofluidic synapse can only perform basic neuromorphic pulse patterns.
One immediate problem that needs to be addressed to further its capability of brain-like
computing is the realization of a nanofluidic spiking device. Here, we report ...
Artificial skins or flexible pressure sensors that mimic human cutaneous mechanoreceptors
transduce tactile stimuli to quantitative electrical signals. Conventional trial-and-error
designs for such devices follow a forward structure-to-property routine, ...
Directional transport of liquids is of great importance in energy saving, chemical/biomedical
engineering, and microfluidics applications. Despite considerable progress in engineering
different open surfaces to achieve liquid manipulation, the realization ...
Adverse cardiac outcomes in COVID-19 patients, particularly those with preexisting
cardiac disease, motivate the development of human cell-based organ-on-a-chip models
to recapitulate cardiac injury and dysfunction and for screening of cardioprotective
...
Physics
Standard deep learning algorithms require differentiating large nonlinear networks,
a process that is slow and power-hungry. Electronic contrastive local learning networks (CLLNs) offer potentially fast, efficient, and fault-tolerant hardware for analog
...
Strange metals exhibit universal linear-in-temperature resistivity described by a
Planckian scattering rate, the origin of which remains elusive. By employing an approach
inspired by quantum optics, we arrive at the coherent state representation of ...
Statistics
Despite evolutionary biology’s obsession with natural selection, few studies have
evaluated multigenerational series of patterns of selection on a genome-wide scale
in natural populations. Here, we report on a 10-y population-genomic survey of the
...
Social Sciences
Anthropology
The human colonization of the Canary Islands represents the sole known expansion of
Berber communities into the Atlantic Ocean and is an example of marine dispersal carried
out by an African population. While this island colonization shows similarities to
...
Psychological and Cognitive Sciences
Functional changes in the pediatric brain following neural injuries attest to remarkable
feats of plasticity. Investigations of the neurobiological mechanisms that underlie
this plasticity have largely focused on activation in the penumbra of the lesion ...
Meta-analyses have concluded that positive emotions do not reduce appetitive risk
behaviors (risky behaviors that fulfill appetitive or craving states, such as smoking
and excessive alcohol use). We propose that this conclusion is premature. Drawing
on ...
Real-world communication frequently requires language producers to address more than
one comprehender at once, yet most psycholinguistic research focuses on one-on-one
communication. As the audience size grows, interlocutors face new challenges that
do ...
Social Sciences
In US cities, neighborhoods have long been racially segregated. However, people do
not spend all their time in their neighborhoods, and the consequences of residential
segregation may be tempered by the contact people have with other racial groups as
they ...
In a context where pessimistic survival perceptions have been widespread as a result
of the HIV/AIDS epidemic (), we study vaccine uptake and other health behaviors during the recent COVID-19 pandemic.
Leveraging a longitudinal cohort study in ...
Sustainability Science
Indonesia has experienced rapid primary forest loss, second only to Brazil in modern
history. We examined the fates of Indonesian deforested areas, immediately after clearing
and over time, to quantify deforestation drivers in Indonesia. Using time-series ...
Biological Sciences
Agricultural Sciences
Trade-offs between evolutionary gain and loss are prevalent in nature, yet their genetic
basis is not well resolved. The evolution of insect resistance to insecticide is often
associated with strong fitness costs; however, how the fitness trade-offs ...
N6-methyladenosine (m6A) is a fundamentally important RNA modification for gene regulation, whose function
is achieved through m6A readers. However, whether and how m6A readers play regulatory roles during fruit ripening and quality formation remains
...
Applied Biological Sciences
Adverse cardiac outcomes in COVID-19 patients, particularly those with preexisting
cardiac disease, motivate the development of human cell-based organ-on-a-chip models
to recapitulate cardiac injury and dysfunction and for screening of cardioprotective
...
Biochemistry
The outer membrane (OM) of gram-negative bacteria serves as a vital organelle that
is densely populated with OM proteins (OMPs) and plays pivotal roles in cellular functions
and virulence. The assembly and insertion of these OMPs into the OM represent a ...
Mammalian transglutaminases, a family of Ca2+-dependent proteins, are implicated in a variety of diseases. For example, celiac
disease (CeD) is an autoimmune disorder whose pathogenesis requires transglutaminase
2 (TG2) to deamidate select glutamine ...
The multinuclear nonheme iron-dependent oxidases (MNIOs) are a rapidly growing family
of enzymes involved in the biosynthesis of ribosomally synthesized, posttranslationally
modified peptide natural products (RiPPs). Recently, a secreted virulence factor ...
Biophysics and Computational Biology
Mesenchymal stem cells (MSCs) are essential in regenerative medicine. However, conventional
expansion and harvesting methods often fail to maintain the essential extracellular
matrix (ECM) components, which are crucial for their functionality and efficacy ...
An array of motor proteins consumes chemical energy in setting up the architectures
of chromosomes. Here, we explore how the structure of ideal polymer chains is influenced
by two classes of motors. The first class which we call “swimming motors” acts to
...
Transcription has a mechanical component, as the translocation of the transcription
machinery or RNA polymerase (RNAP) on DNA or chromatin is dynamically coupled to the
chromatin torsion. This posits chromatin mechanics as a possible regulator of ...
Protein folding and evolution are intimately linked phenomena. Here, we revisit the
concept of exons as potential protein folding modules across a set of 38 abundant
and conserved protein families. Taking advantage of genomic exon–intron organization
and ...
Cell Biology
Adult neural stem cells (NSCs) reside in the dentate gyrus of the hippocampus, and
their capacity to generate neurons and glia plays a role in learning and memory. In
addition, neurodegenerative diseases are known to be caused by a loss of neurons and
...
SLC7A11 is a cystine transporter and ferroptosis inhibitor. How the stability of SLC7A11
is coordinately regulated in response to environmental cystine by which E3 ligase
and deubiquitylase (DUB) remains elusive. Here, we report that neddylation inhibitor
...
Rapid accumulation of repair factors at DNA double-strand breaks (DSBs) is essential
for DSB repair. Several factors involved in DSB repair have been found undergoing
liquid–liquid phase separation (LLPS) at DSB sites to facilitate DNA repair. RNF168,
a ...
Wnt/Wingless signaling promotes lipid mobilization through signal-induced transcriptional repression
The Wnt/Wingless signaling pathway plays critical roles in metazoan development and
energy metabolism, but its role in regulating lipid homeostasis remains not fully
understood. Here, we report that the activation of canonical Wnt/Wg signaling promotes
...
Developmental Biology
Tissue buckling is an increasingly appreciated mode of morphogenesis in the embryo,
but it is often unclear how geometric and material parameters are molecularly determined
in native developmental contexts to generate diverse functional patterns. Here, we
...
Only 30% of embryos from in vitro fertilized oocytes successfully implant and develop
to term, leading to repeated transfer cycles. To reduce time-to-pregnancy and stress
for patients, there is a need for a diagnostic tool to better select embryos and ...
Nutrient sensing and adaptation in the placenta are essential for pregnancy viability
and proper fetal growth. Our recent study demonstrated that the placenta adapts to
nutrient insufficiency through mechanistic target of rapamycin (mTOR) inhibition–...
Hedgehog (Hh) signaling, an evolutionarily conserved pathway, plays an essential role
in development and tumorigenesis, making it a promising drug target. Multiple negative
regulators are known to govern Hh signaling; however, how activated Smoothened (...
Xenopus embryos provide a favorable material to dissect the sequential steps that lead to
dorsal–ventral (D-V) and anterior–posterior (A-P) cell differentiation. Here, we analyze
the signaling pathways involved in this process using loss-of-function and ...
Ecology
Climate warming is causing widespread deglaciation and pioneer soil formation over
glacial deposits. Melting glaciers expose rocky terrain and glacial till sediment
that is relatively low in biomass, oligotrophic, and depleted in nutrients. Following
...
Although climate change is expected to drive tree species toward colder and wetter
regions of their distribution, broadscale empirical evidence is lacking. One possibility
is that past and present human activities in forests obscure or alter the effects
...
Environmental Sciences
Solar particle events (SPEs) are short-lived bursts of high-energy particles from
the solar atmosphere and are widely recognized as posing significant economic risks
to modern society. Most SPEs are relatively weak and have minor impacts on the Earth’s
...
Indonesia has experienced rapid primary forest loss, second only to Brazil in modern
history. We examined the fates of Indonesian deforested areas, immediately after clearing
and over time, to quantify deforestation drivers in Indonesia. Using time-series ...
Evolution
Despite evolutionary biology’s obsession with natural selection, few studies have
evaluated multigenerational series of patterns of selection on a genome-wide scale
in natural populations. Here, we report on a 10-y population-genomic survey of the
...
Genetics
Phoresy is an interspecies interaction that facilitates spatial dispersal by attaching
to a more mobile species. Hitchhiking species have evolved specific traits for physical
contact and successful phoresy, but the regulatory mechanisms involved in such ...
Immunology and Inflammation
Upon encountering allergens, CD4+ T cells differentiate into IL-4-producing Th2 cells in lymph nodes, which later transform
into polyfunctional Th2 cells producing IL-5 and IL-13 in inflamed tissues. However,
the precise mechanism underlying their ...
Multiple sclerosis (MS) is a demyelinating central nervous system (CNS) disorder that
is associated with functional impairment and accruing disability. There are multiple
U.S. Food and Drug Administration (FDA)-approved drugs that effectively dampen ...
Medical Sciences
Functional analysis in mouse models is necessary to establish the involvement of a
set of genetic variations in tumor development. A modeling platform to facilitate
and cost-effectively analyze the role of multiple genes in carcinogenesis would be
...
Efficient storage and sharing of massive biomedical data would open up their wide
accessibility to different institutions and disciplines. However, compressors tailored
for natural photos/videos are rapidly limited for biomedical data, while emerging
deep ...
Targeting cell surface molecules using radioligand and antibody-based therapies has
yielded considerable success across cancers. However, it remains unclear how the expression
of putative lineage markers, particularly cell surface molecules, varies in the ...
Microbiology
Plasmodium falciparum causes severe malaria and assembles a protein translocon (PTEX) complex at the parasitophorous
vacuole membrane (PVM) of infected erythrocytes, through which several hundred proteins
are exported to facilitate growth. The preceding ...
Neuroscience
Functional changes in the pediatric brain following neural injuries attest to remarkable
feats of plasticity. Investigations of the neurobiological mechanisms that underlie
this plasticity have largely focused on activation in the penumbra of the lesion ...
Humans and animals routinely infer relations between different items or events and
generalize these relations to novel combinations of items. This allows them to respond
appropriately to radically novel circumstances and is fundamental to advanced ...
The brain’s neuroreparative capacity after injuries such as ischemic stroke is partly
contained in the brain’s neurogenic niches, primarily the subventricular zone (SVZ),
which lies in close contact with the cerebrospinal fluid (CSF) produced by the ...
Understanding the genesis of shared trial-to-trial variability in neuronal population
activity within the sensory cortex is critical to uncovering the biological basis
of information processing in the brain. Shared variability is often a reflection of
the ...
Parkinson’s disease (PD) is a multifactorial disease that affects multiple brain systems
and circuits. While defined by motor symptoms caused by degeneration of brainstem
dopamine neurons, debilitating non-motor abnormalities in fronto-striatal-based ...
How does the brain process the faces of familiar people? Neuropsychological studies
have argued for an area of the temporal pole (TP) linking faces with person identities,
but magnetic susceptibility artifacts in this region have hampered its study with
...
In adult songbirds, new neurons are born in large numbers in the proliferative ventricular
zone in the telencephalon and migrate to the adjacent song control region HVC (acronym
used as proper name) [A. Reiner et al., J. Comp. Neurol. 473, 377–414 (2004)]...
Advancing the mechanistic understanding of absence epilepsy is crucial for developing
new therapeutics, especially for patients unresponsive to current treatments. Utilizing
a recently developed mouse model of absence epilepsy carrying the BK gain-of-...
Physiology
The pial vasculature is the sole source of blood supply to the neocortex. The brain
is contained within the skull, a vascularized bone marrow with a unique anatomical
connection to the brain meninges. Recent developments in tissue clearing have enabled
...
Dietary lipids play an essential role in regulating the function of the gut microbiota
and gastrointestinal tract, and these luminal interactions contribute to mediating
host metabolism. Palmitic Acid Hydroxy Stearic Acids (PAHSAs) are a family of lipids
...
Female mosquitoes produce eggs in gonadotrophic cycles that are divided between a
previtellogenic and vitellogenic phase. Previtellogenic females consume water and
sugar sources like nectar while also being attracted to hosts for blood feeding. ...
Plant Biology
The MKK3 MAPK cascade integrates temperature and after-ripening signals to modulate seed germination
The timing of seed germination is controlled by the combination of internal dormancy
and external factors. Temperature is a major environmental factor for seed germination.
The permissive temperature range for germination is narrow in dormant seeds and ...
Bioengineering of plant immune receptors has emerged as a key strategy for generating
novel disease resistance traits to counteract the expanding threat of plant pathogens
to global food security. However, current approaches are limited by rapid evolution
...
In recent years, the exploration of genome three-dimensional (3D) conformation has
yielded profound insights into the regulation of gene expression and cellular functions
in both animals and plants. While animals exhibit a characteristic genome topology
...
Leaves of flowering plants are characterized by diverse venation patterns. Patterning
begins with the selection of vein-forming procambial initial cells from within the
ground meristem of a developing leaf, a process which is considered to be auxin-...
DNA is organized into chromatin-like structures that support the maintenance and regulation
of genomes. A unique and poorly understood form of DNA organization exists in chloroplasts,
which are organelles of endosymbiotic origin responsible for ...
Correction
Cover image: Pictured is a composite image of an aurora, a manifestation of interaction between intense solar wind and Earth's geomagnetic field, over Switzerland. Pavle Arsenović et al. modeled the potential impact of extreme solar particle events (SPE) on the ozone layer and surface radiation. Under present geomagnetic conditions, an extreme SPE would deplete the polar ozone layer for around one year. However, under a greatly reduced field, an SPE would deplete stratospheric ozone for several years, increasing the UV index and DNA damage. According to the authors, an extreme SPE could lead to human health hazards and long-term evolutionary effects. See the article by Arsenović et al. e2321770121. Image credit: photo by Julien Anet, edited by Jelisaveta Arsenović (MITarh, Belgrade, Serbia).
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