Proceedings of the National Academy of Sciences

Photosynthetic biomanufacturing offers a sustainable route to generate valuable bioproducts by harnessing microorganisms such as algae to convert sunlight and carbon dioxide into biomass. A major barrier to efficient production is that light penetrates poorly into dense algal cultures, restricting photosynthesis to a thin surface layer and severely limiting the solar energy that can be utilized f…

Ferroelectric nematic liquid crystals (FNLCs) represent an emerging class of functional soft materials that combine the orientational order of nematic liquid crystals with spontaneous electrical polarization. In a striking departure from the conventional nonpolar nematic liquid crystals, FNLCs form freely suspended liquid filaments that thin in time. These filaments exhibit a two-stage thinning d…

Changes to speech offer a quantifiable means to assess speech motor learning, and the resulting memory is thought to be motor in nature. Here, we evaluate this idea and show instead that memory for speech movements has a sensory basis. Speech motor learning, using altered auditory feedback, provides an experimental model to address this question as it involves auditory, somatosensory, and motor c…

Cytotoxic T lymphocytes eliminate infected or malignant cells, safeguarding surrounding tissues. Although experimental and systems-immunology studies have cataloged many molecular and cellular actors involved in an immune response, the design principles governing how the speed and magnitude of T cell responses emerge from cellular decision-making remain elusive. Here, we recast the T cell respons…

Human curiosity is dynamic, however the principles governing its fluctuations remain debated. Here, we test two competing hypotheses about how past learning shapes subsequent curiosity and memory. The first, based on the “optimal arousal” theory, proposes that satisfying curiosity reduces subsequent curiosity. The second, grounded in reinforcement learning, suggests that satisfying curiosity stre…

Synaptic strength is dynamically modulated not only by activity-dependent processes but also by neuromodulators. These modulators can enhance or depress synaptic transmission and play essential roles in circuit function and in the pathophysiology of psychiatric disorders. Although neuromodulation is functionally important in vivo, the underlying cellular mechanisms—particularly at the presynaptic…

Collective cell dynamics are fundamental to numerous physiological processes, including embryo development, tissue morphogenesis, immune response, and disease progression. Accurately modeling these dynamics across scales remains challenging, as traditional physics-based models usually rely on many unmeasurable parameters and unclear active physics, limiting their ability to capture both single-ce…

Sterols, lipids, and carotenoids are major metabolites that share common biosynthetic precursors and underpin key physiological processes in eukaryotes. Yet, how cells coordinate metabolic flux through these competing pathways to maintain homeostasis remains unclear. Here, we identify a conserved RING-type E3 ubiquitin ligase, PTR1, as a central regulatory hub that orchestrates the interplay amon…

The presence of neuromelanin is a characteristic feature of the human substantia nigra (SN); however, the mechanism of its synthesis and its role in the development of Parkinson’s disease remain unclear. Here, we report that the host defense enzyme lactoperoxidase (LPO), which possesses broad antimicrobial activity on mucosal surfaces, is selectively expressed in human dopaminergic neurons, a fea…

Nerve growth factor (NGF) is a member of the neurotrophin family, essential for neuronal survival and phenotypic maintenance. However, in vitro, its function can be disrupted by oxidative posttranslational modifications such as tyrosine nitration. Nitrated NGF (NO 2 NGF) has been shown to have a gain-of-toxic, pro-apoptotic, activity in motoneuron cultures. Herein, we report the generation and ch…

A long-standing engineering problem, the control of soft robots is difficult because of their highly nonlinear, heterogeneous, anisotropic, and distributed nature. Here, bridging engineering and biology, neural reservoirs are employed for the dynamic control of a bio-hybrid model arm made of multiple muscle-tendon groups enveloping an elastic spine. We show how the use of reservoirs facilitates s…

Emerging wearable health monitoring technologies require conformable and stretchable devices. Polymer semiconductors composed of π-conjugated polymer aggregates in an elastomeric matrix are remarkable in their ability to provide both high stretchability and enhanced charge transport. Understanding their film formation process is critical in improving charge transport, imparting added functionalit…

Measuring fast dynamic processes with dynamic light scattering over wide fields of view is critical for applications ranging from blood flow imaging to characterizing complex fluids, yet is often limited by the need for expensive, high frame rate cameras. Here, we introduce sinusoidal intensity modulation speckle imaging (SIMSI), a technique that overcomes this hardware limitation by encoding inf…

In the process of investigating innate immune reactions against injected oncogenic cells in <i>Drosophila</i>, we noted that the homeodomain protein Engrailed, known since last century for its role in segmentation polarity in embryos, is reactivated in adult males where it considerably restricts the expected proliferation of these cells. Importantly, this effect was not induced following injectio…

Several theoretical models predict that spatial patterning increases ecosystem resilience. However, these predictions rely on simplifying assumptions, such as assuming isotropic and infinitely large ecosystems, and empirical evidence directly linking spatial patterning to enhanced resilience remains scarce. We introduce a unifying framework, encompassing existing models for vegetation pattern for…

Extracorporeal life support, such as hemodialysis, often face the risk of blood coagulation, where systemic anticoagulation with heparin is routinely administered. However, this strategy is contraindicated in patients at high risk of bleeding. Inspired by the observation that rolling motion of spherical platelets avoids their exposure to tangential forces, an anticoagulation strategy is proposed …

Paligenosis is a conserved cellular plasticity program that allows mature cells to reenter the cell cycle in response to tissue injury. Paligenosis progresses via three stages: autodegradation (with dramatic increase in autophagy and lysosomes), induction of metaplastic or fetal-like genes, and cell cycle entry. Hippo signaling, particularly the downstream effector YAP1, regulates cellular plasti…

Understanding and manipulating the spread of mobile genetic elements represents a great challenge with potential benefits across synthetic biology, agriculture, and medicine. A key part of this challenge is the multiple scales in play, from the molecular kinetics of defense systems such as CRISPR-Cas, to single-cell variability in immunity levels, to spatial structure in bacterial populations. In…