Biology subjects

Li, S.

Publications and source records attributed to Li, S..

At least 271 records · Page 15Linked to original sources

bioRxiv2025

Developmental sleep reallocation enables metabolic adaptation in desert flies

Sleep is essential for adaptation and survival across the lifespan, yet the ecological pressures shaping sleep ontogeny remain poorly understood. We investigated sleep across early developmental stages in Drosophila mojavensis, a stress-resilient desert-adapted species. While adult D.mojavensis exhibit prolonged and consolidated sleep, along with enhanced starvation tolerance and survival compared to Drosophila melanogaster, the developmental trajectory underlying these adaptation strategies for surviving in harsh environments is unknown. Moreover, during developmental (larval) periods, animals do not encounter the same environmental stressors experienced by adults (e.g., food scarcity, extreme temperatures). We find that in contrast to adults, D.mojavensis larvae exhibit reduced and fragmented sleep relative to D.melanogaster. D.mojavensis larval sleep is also deeper, reflecting a shift toward increased sleep efficiency rather than simple sleep loss. D.mojavensis larvae consume more food than D.melanogaster and survive longer under starvation, suggesting a strategic tradeoff by suppressing sleep to prioritize nutrient intake and energy storage early in life while resources are more abundant. Metabolic analyses reveal elevated triglyceride accumulation in D.mojavensis across their lifespan, indicating enhanced energy storage capacity. These findings provide an example of how, within a fixed genetic background, an animal can reallocate sleep in opposing manners to maximize survival and energetics depending upon ecological pressures unique to each phase of life.

neuroscience↗

bioRxiv2025

Effective repurposed antivirals against an emerging virus

The ongoing global monkeypox virus (MPXV) outbreak urgently needs effective medications, which be accelerated through drug repurposing. However, it is challenging to poinpoint protein targets. Here we introduce a novel method rooted in molecular evolutionary theory for quick drug target identification for MPXV. It identifies drug targets as positively selected genes of viral proteins which bind host proteins. From the identified targets, we select a top gene product OPG021 for virtural drug screening. One top-ranked drug nilotinib is experimentally shown to have a significant 69% of antiviral efficacy of the FDA-approved antiviral tecovirimat (TPOXX(R) or ST-246). Higher binding affinity but not antiviral efficacy of repursposed drugs than FDA-approved drugs suggests the complexity of drug repurposing and underscores the importance of experimental validation. This innovative drug target identification strategy will contribute to combating the ongoing MPXV outbreak and other viral acute and chronic viral diseases.

pathology↗

bioRxiv2025

Multiple protein-protein interactions drive the assembly and budding of the Chikungunya virion

The assembly of enveloped viruses is a highly orchestrated process that depends on the coupling of multiple protein-protein interactions within a membrane environment. To gain mechanistic insight into this process, we use Chikungunya virus as a model system to study Alphavirus assembly, focusing on the interplay between core-spike and spike-spike interactions. We begin with coarse-grained molecular dynamics simulations to systematically explore how the symmetry of the nucleocapsid core, together with the relative strengths of spike-core and spike- spike interactions, influences budding efficiency and the emergence of icosahedral particle symmetry. Building on these computational predictions, we perform site-directed mutagenesis on Chikungunya virus 181/25 and examine the consequences for particle assembly and budding in cultured cells, as well as the impact of these mutations during in-cellulo assembly. Our results reveal that canonical core-spike interactions, while necessary, are not sufficient for successful assembly. Instead, lateral interactions among glycoproteins emerge as critical determinants of efficient budding, particle stability, and the maintenance of icosahedral symmetry. Together, these findings provide an integrated computational and experimental framework for understanding the molecular principles governing Alphavirus assembly.

biophysics↗

bioRxiv2025

Attention Improves Population Codes by Warping Neural Manifolds in Human Visual Cortex

Decades of research on visual attention have revealed its numerous effects on neural responses. Two competing models have been proposed for how these effects lead to improved population representations: one highlights changes in neural tuning, while the other points towards changes in trial-by-trial noise correlations. Here, we develop a neural population manifold framework that interprets changes in neural responses as geometric transformations in high-dimensional neural space, allowing us to disentangle and quantify the effects of tuning changes and correlation changes induced by attention. Applying this framework to extensive measurements of cortical responses during different attentional tasks, we find that tuning changes are the primary driver of improved population representations. In contrast, correlation changes, though present, have minimal--or even detrimental--effects to information content due to its strong interactions with other changes (e.g., tuning, variability). Our results support the "tuning change" model of visual attention and demonstrate a general framework for adjudicating how different aspects of neural coding affect information processing.

neuroscience↗

bioRxiv2025

Clustering of SARS-CoV-2 membrane proteins in lipid bilayer membranes

The accumulation of viral structural proteins along the ER-Golgi intermediate compartment (ERGIC) membrane leads to SARS-CoV-2 self-assembly and budding, driven by the interactions between these proteins, RNA and the ERGIC membrane. The membrane protein (M) is believed to interact with other structural proteins and form clusters needed for the induction of membrane curvature that facilitates virion formation. However, the role played by direct and membrane-mediated interactions between M proteins and their interactions with other proteins in the clustering process remains unclear. Here, we utilize a combination of all-atom molecular dynamics (MD) simulations, continuum modeling and experiments to show that M-M interactions are sufficient to drive clustering in ERGIC-like lipid bilayers in the absence of other proteins or RNA. Using all-atom MD simulations we were able to estimate the membrane thinning induced by M proteins and the resulting membrane-mediated M-M interaction. Combining this with a continuum model that describes the evolution of M protein density in a planar lipid membrane, we identified the existence of a critical, direct M-M interaction energy needed for cluster assembly at a given density. By comparing the model predictions with analysis of atomic force microscopy images of M protein clusters in supported lipid bilayers, we were able to estimate the direct M-M interaction energy and found it to be significantly larger than the membrane mediated interaction energy. Our work therefore establishes that M protein interactions are sufficient to drive clustering and provides a quantitative understanding of the role played by direct and membrane-mediated interactions of M proteins in viral assembly and budding.

biophysics↗

bioRxiv2025

An antifungal with a novel mechanism of action discovered via resistance gene-guided genome mining

Invasive fungal infections claim over two million lives annually, a problem exacerbated by rising resistance to current antifungal treatments and an increasing population of immunocompromised individuals. Despite this, antifungal drug development has stagnated, with few novel agents and fewer novel targets explored in recent decades. Here, we validate acetolactate synthase (ALS), an enzyme critical for branched-chain amino acid biosynthesis and absent in humans, as a promising target for new therapeutics. Using resistance gene-guided genome mining, we discovered a biosynthetic gene cluster in Aspergillus terreus encoding HB-35018 (1), a novel spiro-cis-decalin tetramic acid that potently inhibits ALS. Biochemical and antifungal assays demonstrate that 1 surpasses existing ALS inhibitors in efficacy against Aspergillus fumigatus and other pathogenic fungi. Structural studies via cryo-electron microscopy reveal a unique covalent binding interaction between compound 1 and ALS, distinct from known inhibitors and finally, we demonstrate that ALS is essential for the virulence in a mouse model of invasive aspergillosis. These findings position ALS as a promising target for antifungal development and demonstrate the potential of resistance gene-guided genome mining for antifungal discovery.

bioengineering↗

bioRxiv2025

Non-redundant roles for paralogous proteins in the yeast glucose-sensing pathway

Paralogs engage in biological processes through both redundant and non-redundant functions. In the yeast Saccharomyces cerevisiae, approximately one-fifth of the genome consists of paralogs, with their encoded proteins involved in multiple pathways. However, the unique contributions of individual paralogs have remained poorly defined. Here, we undertook a systematic examination of eight paralog pairs in the glucose-sensing pathways, deleting each component and measuring the resulting changes in gene expression. To that end we established a new transcription reporter system to monitor the response to glucose as well as to non-preferred sugars in single cells. Focusing on the PKA catalytic subunits, comprised of the paralogs Tpk1 and Tpk3 as well as the isomorphic kinase Tpk2, we employed mass spectrometry to identify their contribution to cellular metabolism, used a GFP-based sensor to follow changes in cytosolic pH, and used BioID to identify unique and shared binding partners. Our data reveal that paralogs in the glucose-sensing pathway contribute in multiple and unique ways to signal transduction, and establish potential mechanisms driving the preservation of these and other duplicated genes throughout long periods of evolution.

genetics↗

bioRxiv2025

Calcium-Regulated Mitochondria Remodeling by Myo19 is Required for Filopodia Tip-Extension

Mitochondria are highly adaptable organelles that change their shape, distribution, and movement to meet cellular needs. We investigate how EGF stimulation remodels mitochondrial behavior in human A431 carcinoma cells, where EGF suppresses proliferation but enhances calcium signaling and cell motility. EGF triggers mitochondrial fission, resulting in smaller, more mobile mitochondria that relocate to the tips of newly formed filopodia. Mitochondrial transport involves Kif5B (microtubule-based) and Myo19 (actin-based) motor proteins, which are regulated differently by calcium. EGF stimulation increases cytosolic calcium, weakening Kif5B-mediated transport and making Myo19 the primary transporter. Mitochondrial calcium uptake through the MCU channel is essential for redistribution, shape changes, and filopodia extension. Disrupting mitochondrial fission or calcium buffering impairs mitochondrial motility and the formation of filopodia. High-resolution imaging reveals the coordinated transport of mitochondria, involving fission, motor switching, and localized calcium signaling. We provide insights into how mitochondrial transport supports actin remodeling and protrusive activity, with implications for cell migration and therapies targeting mitochondrial-cytoskeletal interactions. HIGHLIGHTSO_LIEGF stimulation remodels the morphology of the mitochondrial network C_LIO_LIKif5B and Myo19 are required for mitochondrial motility C_LIO_LIMitochondria display two different velocities depending on the cell region C_LIO_LICalcium homeostasis contributes to mitochondrial network remodeling C_LI eTOC BLURBCell powerhouses called mitochondria can change shape and move within cells along tracks called the cytoskeleton. Stimulation of cells by stressors, such as growth factors, can generate signals that cause mitochondria to migrate to the cell edges using molecular motors. Importantly, this movement enables cells to form finger-like projections, providing the energy necessary for cell migration.

cell biology↗

bioRxiv2025

Engineering magnetically guided bacteriophages for precision antimicrobial therapy and targeted biofilm eradication

Viruses, including bacteriophages, rely on passive diffusion to reach their hosts, limiting the efficacy of virus-based therapies and leading to off-target accumulation with systemic effects. Here, we present a strategy to confer controllable motility to bacteriophages by incorporating iron nanoparticles (FeNPs) into their head structures while preserving infectivity. Cryo-electron microscopy (Cryo-EM) and transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) confirmed the FeNP presence in the phages head. FeNP-tagged phages can be magnetically enriched and isolated from bacterial prey cultures, eliminating the need for ultracentrifugation. Under magnetic guidance, these engineered phages exhibit rapid and directed movement through complex microenvironments, including mazes and polymer barriers, enabling precise bacterial targeting and biofilm eradication in a microfluidic system. In an in vivo wound infection model, magnetically guided phages successfully navigated from the peritoneum to the biofilms on the wound, thus selectively eliminating biofilms while minimizing systemic exposure to other organs. Hence, our approach confers viral mobility, thus enhancing the precision and efficacy of bacteriophage-based biotechnological and therapeutic applications.

microbiology↗

bioRxiv2025

Quantitative Prevalence, Chemical Speciation, and ECM-Embedded Networks of Biogenic Silicon in Animal Tissues Revealed by Refined Analytical Methods

Silicon, abundant in Earths biosphere, plays crucial roles in many organisms. However, its biological functions in animals remain inadequately characterized, primarily constrained by methodological limitations in quantifying, identifying, and visualizing biogenic silicon in tissues. Here, we refined the molybdenum blue colorimetric method (MB) for more accurate silicon quantification, developed integrated mass spectrometry techniques to delineate chemical natures of biogenic silicon, and optimized micro-X-ray fluorescence (micro-XRF) imaging for spatial mapping in animals. Employing these methodologies, we demonstrated that silicon abundance in animals substantially exceeds prior estimates--surpassing essential elements like iron. We also revealed the chemical architectures of diverse silicon compounds and visualized tissue-specific distributions in mice and humans, indicating its predominant localization within extracellular matrix (ECM) and suggesting the formation of silicified networks. These findings establish silicon as a structurally and quantitatively significant element with profound biological implications, warranting its recognition as an essential factor in human physiology and pathology.

biochemistry↗

bioRxiv2025

PDE3A2 modRNA Fine-Tunes Nuclear cAMP Microdomains and Reverses Pathological Cardiac Hypertrophy

Pathological cardiac hypertrophy (PCH) is a precursor to heart failure, driven in part by dysregulated nuclear-localized cAMP (NLS-cAMP) signaling. Phosphodiesterase 3A2 (PDE3A2) is a key regulator of this nuclear cAMP microdomain, yet its selective modulation remains challenging. Here, we developed PDE3A2-modified RNA (PDE3A2-modRNA) to restore nuclear PDE3A2 levels and tested its efficacy in an angiotensin II-induced PCH model. Subcellular FRET imaging revealed that PCH hearts exhibit hyperactive NLS-cAMP due to PDE3A2 depletion. PDE3A2-modRNA selectively reduced NLS-cAMP without altering cytosolic cAMP, demonstrating precise microdomain regulation. In vivo, PDE3A2-modRNA improved cardiac function, attenuated hypertrophy and fibrosis, and shifted transcriptional programs toward physiological remodeling. Single-nucleus transcriptomics and immune profiling further revealed reduced oxidative stress and an improved cardiac microenvironment. These findings highlight PDE3A2-modRNA as a novel gene therapy that selectively restores nuclear cAMP homeostasis, reversing PCH-promoting transcriptional programs while preserving physiological cAMP signaling in cytosolic microdomains.

pathology↗

bioRxiv2025

Directed evolution of a compact TranC11a system for efficient genome editing

The recently discovered TranC systems represent programmable RNA-guided DNA endonucleases of transposon origin with compact protein sizes ideal for therapeutic delivery. However, their editing efficiency in human and plant cells is limited. Here, we evolved TranC11a and engineered its sgRNA to enhance overall editing efficiencies. TranC11a systems exhibit up to 9.2-fold higher editing activity than its parent and achieves efficiency comparable to SpCas9 across multiple human genome endogenous sites, significantly outperforming compact editors NovaIscB and enTnpB1c. TranC11a enables efficient editing of disease-relevant genes in human cells and breeding traits in maize. With its high editing activity and compact size (574 aa), TranC11a demonstrates strong potential for future in vivo genome editing and crop engineering.

synthetic biology↗

bioRxiv2025

Human SerRS/SIRT2 complex structure reveals cross regulation between translation and NAD+ metabolism

Life at the cellular level depends on effective coordination between diverse processes. Here we uncover a novel cross-regulation between metabolism and translation through a 3.2 [A] cryo-EM structure of human cytosolic seryl-tRNA synthetase (SerRS) bound to sirtuin-2 (SIRT2), an NAD+-dependent deacetylase. This interaction, naturally triggered by the NAD+ metabolite ADP-ribose (ADPR), resembles substrate binding and block SIRT2s active site. Interestingly, SerRS acetylation is not required for this interaction. SIRT2 binding sterically and allosterically impedes tRNA binding to SerRS, lowering charged tRNASer level and protein synthesis activity. Key interaction residues in both proteins emerged simultaneously in vertebrates, suggesting co-evolution for cross-regulation. Given ADPRs accumulation under stress, the ADPR-induced SerRS/SIRT2 interaction likely serves as a cell-protective response.

molecular biology↗

bioRxiv2025

Synthetic microbial co-cultures for modular bioelectronic sensing in diverse environments

Human disruption of ecosystems poses a significant threat to global health, driving the need for low-cost, low-power, and easily deployable sensors for environmental and health monitoring. Microbial bioelectronic sensors are particularly well-suited as they generate electrical signals and can be integrated into compact electronic devices for field deployment over extended periods. However, current engineering strategies for bioelectronic sensors lack modularity, are limited to a few microbial chassis, and depend on specialized instruments for signal detection. Here, we present the electroactive co-culture sensing system (e-COSENS), a plug-and-play platform for bioelectronic sensor development. This system comprises a "sender" bacterium that produces electron mediators in response to analytes and a "receiver" bacterium that utilizes the electron mediators to generate electrical signals via extracellular electron transfer (EET). By modularly swapping the sender bacterium and its associated genetic sensing elements, we achieved bioelectronic sensing of metals, small molecules, and peptides in distinct environmental, food, and human-relevant settings. Moreover, we designed a centimeter-sized bioelectronic device that enables low-cost, portable signal readout from e-COSENS using a household digital multimeter. The e-COSENS platform greatly simplifies the bioelectronic sensor design and opens unprecedented potential for bioelectronic sensor applications.

synthetic biology↗

bioRxiv2025

Distinct ATRX functions cooperate with 9-1-1 and CST complexesto safeguard replication and telomere integrity

Mutations in the ATRX chromatin remodeller predispose to a developmental genetic disorder and cancer, but how it safeguards genome and telomere stability remains unresolved. Here, we uncover critical dependencies for the CTC1-STN1-TEN1 (CST) complex and RAD9A-HUS1-RAD1 (9-1-1) clamp in ATRX deficient cells. ATRX:CST synthetic lethality manifests following accumulation of telomeric G-rich ssDNA, which results in telomere loss and cell death. Conversely, we attribute ATRX:9-1-1 synthetic lethality to genome-wide ssDNA lesions, which compromise DNA replication. We further show ATRX suppresses DNA damage during replication stress by counteracting the activity of the FAM111A protease. We demonstrate that roles of ATRX in telomere maintenance and replication are genetically separable requiring its ATPase activity and PIP-box, respectively, and independently of its DAXX interaction. Collectively, functions of ATRX in suppressing toxic ssDNA lesions are context-dependent and are key to global DNA replication and telomere integrity.

molecular biology↗

bioRxiv2025

Anaerobic gut fungi Caecomyces communis, Neocallimastix frontalis and Piromyces spp. nov., have distinct effects on plant fibres during digestion.

Anaerobic gut fungi are the first colonizers of plant material that enters the digestive system of ruminants. However, it is unclear how different fungal species contribute to the ability of the rumen microbiome to convert feed to nutrients. Here we isolated three species of anaerobic fungi, including a novel Piromyces species. We investigated if these species have distinct roles in the digestion of fibrous feed components, via assessment of changes caused to plant material itself. We found Neocallimastix frontalis isolate CoB3 and Piromyces isolate SHC digested plant materials more effectively than Caecomyces communis isolate SHB. The three fungi had distinct effects on feed composition. N. frontalis CoB3 degraded hemicelluloses and cellulose to a similar extent, Piromyces spp. SHC preferentially degraded hemicellulose, while C. communis SHB preference depended on the substrate. From the panel of monosaccharides that may result from such degradative activity, all fungi consumed only glucose, suggesting involvement of mechanisms more complex than only fungal carbon source usage. Overall, this indicates that each of these fungal species have distinct roles in the degradation of plant material, and different niches in the rumen. Exploring these roles creates functional understanding of the rumen microbiome, critical for developing more sustainable agriculture.

microbiology↗

bioRxiv2025

Recognition of Ovarian Tumor-Derived Non-canonical Peptide Induces Memory-Like Features in Natural Killer Cells

Immune cell-based immunotherapy has emerged as a promising strategy for both hematologic malignancies and solid tumors. The adaptive properties of T and B cells, namely, antigen specificity and long-term immune memory, form the foundation of approaches such as chimeric antigen receptor (CAR) T-cell therapy and tumor vaccines. In contrast, natural killer (NK) cells, traditionally classified as innate lymphocytes, have been appreciated primarily for their immediate cytotoxicity against tumor cells, but not for long-term memory-like responses. Recent evidence has revealed a subset of NK cells defined as adaptive NK cells (aNK) capable of developing adaptive features, particularly in response to cytomegalovirus (CMV) primarily, and more recently, to ovarian tumor-derived antigens. However, whether tumor-derived peptides can specifically induce NK cell memory, and the corresponding interaction patterns, remains largely unexplored. In this study, we employed a proteogenomic approach combining RNA sequencing (RNA-seq) with HLA-E immunoprecipitation to identify both canonical and non-canonical peptides presented by primary ovarian tumor cells. Among four tumor-derived neo-antigenic peptides, the 9-mer peptide APAPAPAPL demonstrated the strongest binding affinity to HLA-E and engagement with the NK receptors NKG2C/A. Functional in vitro assays confirmed that this peptide could induce memory-like NK cell responses, including antigen-specific recall activity and enhanced tumor cytotoxicity. Furthermore, structural modeling using AutoDock Vina and Rosetta Dock illustrated that peptides with similar binding capacity shared conserved interaction patterns and docking orientations. Together, this systemic study highlights a novel mechanism for inducing NK cell memory through tumor-derived neoantigens. It also paves the way for the development of NK cell-targeted cancer vaccines, representing a new direction in tumor immunotherapy beyond conventional T cell-centered strategies.

immunology↗

bioRxiv2025

Navigating methodological decisions: Balancing rigor and data volume of the Canadian Living Planet Index

The Living Planet Index -- a biodiversity indicator that assesses the relative change of aggregate vertebrate abundance data -- is an indicator used in global and national biodiversity monitoring frameworks. In Canada, the LPI has been modified (C-LPI) -- adopting differing methodological choices relative to the global LPI. However, there is no clear consensus on the most appropriate analytical methods, particularly as they pertain to the treatment of zeros, confidence intervals and uncertainty, time series length and number of data points required, modelling of short time series, removal of outliers, weighting species, and the impact of baseline year selection. Our analysis transparently explores multiple methodological options and the consequent C-LPI output for each of these decision points. Our research does not evaluate the superiority of a single approach but rather provides transparency and accountability in C-LPI reporting. We hope that this will further strengthen the utility of the C-LPI and provide decision makers with the necessary information to appropriately interpret patterns, evaluate progress towards biodiversity targets, and inform conservation action.

ecology↗