Biology subjects

Singh, P.

Publications and source records attributed to Singh, P..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

Continuous In Vitro Propagation of the Human Pathogen Babesia microti in Human Erythrocytes

Withdrawal StatementThe authors have withdrawn this manuscript because follow-up molecular authentication and validation studies of cryopreserved early and later parasite passages identified discordant species-specific PCR signals, including evidence of both Babesia microti and Babesia duncani markers in some archived cultures, indicating that the culture history and the timing of contamination or species overgrowth remain unresolved and may materially affect the conclusions of the study. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

microbiology↗

bioRxiv2026

A Scalable Design for Proximity-Inducing Molecules

Chimeric molecules, which bring together an effector enzyme and a protein-of-interest (POI) to add/remove post-translational modifications (PTMs), are furnishing transformative modalities (e.g., PROTACs). However, these chimeras scalability is limited as they employ rare, non-inhibitory binders of effectors. We report GRoup-transfer chimeras for Inducing Proximity (GRIPs) that employ abundantly available effectors inhibitors to append POI binder on the effector using group-transfer handles. To demonstrate scalability, we develop 6 GRIPs classes for 3 PTMs utilizing diverse inhibitor, spanning 16 effector-POI pairs. Furthermore, we report a toolbox of 42 tunable group-transfer handles for Cys/Lys residues and [~]5000 inhibitor-residue pairs for diverse effectors. Using global proteomics, we confirm the specificity for group transfer and PTM editing. GRIPs endowed new functionalities to POI drugs, including preventing rebound signaling upon drug withdrawal, a more potent/persistent inhibition, and inhibitor-induced pathway activation in 4 fully-endogenous systems. In diverse hemi-endogenous systems (tagged POI), GRIPs induced condensate formation with reduced off-targets, cleared pathogenic PTMs, and initiated PTM crosstalk. Overall, GRIPs provide a scalable and versatile platform for PTM editing. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/706349v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@132f70dorg.highwire.dtl.DTLVardef@f9aa62org.highwire.dtl.DTLVardef@12143edorg.highwire.dtl.DTLVardef@f296d4_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2026

Neuropeptide Y deficiency in the bone marrow drives hematopoietic stem and progenitor cell aging

Aging-related blood disorders are linked to defects in the regenerative and multilineage differentiation ability of hematopoietic stem and progenitor cells (HSPCs). While remodeling of the bone marrow (BM) microenvironment where HSPCs reside is known to contribute to these age-associated defects, the underlying factors and mechanisms remain poorly defined. Here, we discovered that the age-related decline of the neurotransmitter neuropeptide Y (NPY) in the BM is a critical driver of HSPC dysfunction. Using mouse models, we demonstrated that NPY levels decrease in the BM with age, and that genetic NPY overexpression or exogenous NPY administration in old mice substantially reverses aging-associated phenotypic and functional defects in HSPCs. Transcriptome analysis revealed that NPY supplementation in old mice restores aging-disrupted molecular pathways in their HSCs, including oxidative stress responses, myeloid differentiation, stemness, mitochondrial activity, and RhoA signaling. However, NPY genetic loss in young mice led to a decline in HSCs regenerative capacity and increased oxidative stress. Importantly, NPY levels also decline in elderly humans, and ex vivo treatment of human BM-derived HSPCs with NPY enhances their in vivo repopulating capacity. These results suggest that NPY supplementation or preservation of NPY-producing nerve fibers could be a therapeutic strategy to rejuvenate aged HSC function.

cell biology↗

bioRxiv2026

Polygenic and redundant architectures of climate-adaptive traits may complicate genomic predictions of maladaptation

SignificanceUnderstanding the genetic basis of local adaptation is an important step to predict species responses to climate change. Current predictions of maladaptation to climate in trees, however, rely mostly on genotype-environment associations, which overlooks the complexity of genetic architectures underpinning climate-adaptive traits. Based on genotype-phenotype associations, we unveil key aspects of the polygenic architecture of drought tolerance and cold hardiness in two lineages of a widespread conifer. Our results suggest that predictions based solely on climate-associated alleles may mischaracterize maladaptation to future climates due to mismatches between the distribution of climate-associated alleles and alleles contributing to adaptive traits. We also show that cold hardiness and drought tolerance evolved largely independently in the two lineages, and with little pleiotropy between traits. Understanding the genetic architecture of climate-adaptive traits can help predict responses to climate change and inform management strategies that mitigate the effects of future climates. By characterizing the genetic basis of adaptation to spatially varying climate conditions, models can predict response to temporal change in climate by extrapolating from spatial patterns of variation. However, such methods are predicated upon a simple genetic basis, with a linear relationship between allele frequency, phenotype, and environment. Here, we explore the nature of the mapping between genotype, phenotype, and climate adaptation in Douglas-fir, an important North American conifer. Using two large common garden experiments combined with exome sequencing and case-control genome-wide association tests, we found that drought tolerance and cold hardiness in two Douglas-fir varieties (Pseudotsuga menziesii var. menziesii and var. glauca) are highly polygenic with little pleiotropy between the two traits. The two varieties showed little repeated evolution in the genetic basis of drought tolerance and none for cold hardiness. Allelic clines were observed along geographic and climatic gradients across 74 natural populations, but their direction of effect was often inconsistent with phenotypic clines. Our findings reveal that the genomic variation underlying climate-adaptive traits is remarkably complex, with redundancy likely playing a key role in the evolution of the divergent polygenetic architectures of abiotic stress tolerance. This suggests that predicting maladaptation to climate based solely on climate-associated alleles may misrepresent future adaptive responses. Genomic predictions and management practices should focus on individual lineages and consider the particularities of the genetic architecture of climate-adaptive traits.

evolutionary biology↗

bioRxiv2026

PRDX6 Modulates Immune Checkpoint Inhibitor Response by Antagonizing Ferroptosis Induced By HDAC Inhibitors

Therapeutic resistance limits the efficacy of histone deacetylase (HDAC) inhibitors and immune checkpoint therapies in cancer. While HDAC inhibitors can induce ferroptosis, tumor cells often evade this cell death via antioxidant defenses. Here we identify peroxiredoxin 6 (PRDX6) as a critical modulator of resistance to HDAC inhibitor largazole by suppressing ferroptosis through its phospholipase A2 activity and maintaining GPX4 expression. Using genome-wide CRISPR activation screening, biochemical assays, and syngeneic tumor models, we show that PRDX6 depletion enhances largazole-induced lipid peroxidation, ferroptotic stress, and reshapes the tumor microenvironment to promote T-cell infiltration and inflammatory cytokine release. Importantly, combining PRDX6 knockdown with HDAC inhibition potentiates anti-PD-L1 immunotherapy efficacy and prolongs survival in vivo. These findings reveal PRDX6 as a redox gatekeeper linking ferroptosis resistance to immune evasion and suggest that co-targeting PRDX6 and HDAC pathways may improve responses to cancer immunotherapy.

cancer biology↗

bioRxiv2026

New paradigm of CRISPR spacerome for classification of global Escherichia coli lineages

Our research team has recently identified a proof-of-concept for a previously unrecognized spacerome signature in a subset of globally distributed E. coli. Motivated by our initial observation, we pursued a more in-depth CRISPR spacerome analysis, which revealed a novel insight in discrimination of global E. coli sequence type (ST) lineages. We systematically retrieved publicly available E. coli complete genomes, analyzed and compared CRISPR spacerome of globally distributed strains. We found that global strains harbored spacerome that has remained conserved spaceromes for decades across multiple continents. Strains with the conserved spacerome belong to specific ST lineages of clinical importance. In addition, most protospacers were assigned to Gammaproteobacteria and Caudoviricetes. Our findings reveal unexpected long-term conservation of CRISPR spaceromes and their potential as high-resolution markers for E. coli epidemiological tracking.

microbiology↗

bioRxiv2026

Stress-responsive roles of the C. neoformans human-like eIF3 complex

Eukaryotic translation initiation factor 3 (eIF3) is a complex of proteins that plays a pleiotropic role in translation regulation across eukaryotes, but the composition of eIF3 complexes varies with retention and loss of subunit genes across evolution. The model yeast Saccharomyces cerevisiae encodes six eIF3 subunits whereas mammals encode thirteen subunits. The basidiomycete fungus and opportunistic fungal pathogen, Cryptococcus neoformans, encodes a mammalian complement of eIF3 subunits. In this report, we investigated the contribution of the non-essential eIF3 subunit genes to cryptococcal stress tolerance. We found that mutants in the four nonessential subunits, eIF3d, eIF3e, eIF3k and eIF3l all exhibit sensitivity to mitochondrial perturbation, and that mutants in eIF3d and eIF3e exhibit opposite susceptibilities to the antifungal drug fluconazole and the hypoxia mimetic cobalt chloride. Loss of eIF3d resulted in reduced eIF2 phosphorylation in response to stress, but the mutant was still able to repress translation to the same extent as the wild type and was defective in induction of integrated stress response regulon. Despite producing higher levels of urease and melanin, the eIF3d deletion mutant was avirulent in Galleria mellonella larvae. Together our data demonstrates the importance of C. neoformans eIF3 in stress adaptation and pathogenesis. ImportanceCryptococcus neoformans is an opportunistic fungal pathogen that causes cryptococcal meningoencephalitis in immunocompromised individuals leading to [~]120,000 deaths worldwide annually. When C. neoformans is exposed to host-relevant stressors, such as oxidative stress and thermal stress, it reprograms the translating pool of mRNAs to favor stress adaptation. Eukaryotic translation initiation factor 3 is a multi-subunit complex with roles in stress-responsive translation across eukaryotes yet is unexplored in C. neoformans. We found that C. neoformans encodes orthologues of all thirteen mammalian eIF3 subunits. Mutational analysis of non-essential subunits implicated eIF3 in responses to mitochondrial stress and antifungal susceptibility in C. neoformans, and demonstrates a role for eIF3d in the induction of the integrated stress response as well as in Cryptococcal pathogenesis. Further work will investigate the specific mRNAs that are regulated by eIF3 in response to host-relevant stressors in C. neoformans.

microbiology↗

bioRxiv2026

In HSV-1, the LAT Enhancer Drives Pre-IE VP16 Transcription to Initiate Reactivation

The HSV-1 VP16 protein, delivered to the nuclei of epithelial cells from the tegument layer of infecting virions, drives viral Immediate-Early (IE) transcription to initiate productive (lytic) infection. Latent HSV-1, established in sensory neurons, reactivates to a lytic infection in the absence of a recent de novo infection event that would deliver tegument proteins like VP16. Therefore, the role of the protein VP16 in the exit from HSV-1 latency has been hotly debated for decades. Here we show that VP16 transcription during latency is silenced by CTCF and cohesin proteins bound to a newly identified CTCF insulator site. Upon a reactivation stimulus, CTCF and cohesins are evicted and VP16 is transcribed prior to, and in the absence of, any other viral transcription. We previously identified long-range cis spatial interactions between the LAT and VP16 loci of the latent HSV-1 genome. Here, our data further indicate that the LAT enhancer serves as a neuron-specific enhancer of VP16 transcription during reactivation. Collectively, we show the HSV-1 latent genome is hard-wired for reactivation by a long-range spatial interaction between the viral gene encoding the protein that initiates lytic phase transcription (VP16) and the viral enhancer element that drives its transcription (LAT enhancer). Author SummaryHerpes Simplex Virus 1 (HSV-1) is a significant lifelong human pathogen that infects 70% of adults worldwide. HSV-1 establishes a persistent latent infection in the peripheral nervous system where the virus can periodically reactivate in response to environmental stressors. These reactivation events result in recurrence of corneal infections that can lead to corneal blindness. It is becoming clear that CTCF insulators play a key role in the maintenance of gene silencing in DNA viruses that can establish latency. CTCF insulators are essential regulators of chromatin structure and play vital regulatory roles in transcriptional control of DNA viruses by organizing chromatin architecture during both latent and lytic stages of virus lifecycles. Here we have identified and functionally characterized a novel CTCF insulator, located at the transactivating gene VP16. We provide evidence that this insulator is involved in silencing VP16 during latent infection, while eviction of insulator protein coincides with increased VP16 gene expression during reactivation. To our knowledge, these are the first data that show that CTCF insulators is a key regulatory element in the exit from latency in a VP16-dependent manner and has important implications in understanding the heterogeneity of HSV-1 reactivation in different populations of neurons.

microbiology↗

bioRxiv2025

A yeast model of 5-oxoproline accumulation reveals a general toleration to 5-oxoproline

5-oxoproline (5-OP) or pyroglutamic acid is an intermediate of the degradation arc of the glutathione cycle. It is metabolized into glutamate through the action of the 5-oxoprolinase enzyme, the only enzyme known to act on this metabolite. 5-OP has long been known to be relatively inert with a proposed role as an osomoprotectant. Recent studies on the 5-oxoprolinase enzyme in mammalian cells have, however, shown that knockdown or deletions of the 5-oxoprolinase make mice (and humans) prone to heart failure. This was ascribed to oxidative stress due to a two-fold elevation in 5-OP. To examine the consequences of 5-oxoproline accumulation more rigorously, we have created a yeast model for 5-oxoproline accumulation. We observed retardation of growth only when intracellular levels of 5-OP were increased 12-20 fold over the normal levels. A transcriptomics study was carried out under these conditions. We observed that while a large number of genes were regulated upto 2-fold, there were no single prominent pathways amongst them. Among the key genes upregulated were different efflux pumps. Using knockouts and also overexpression of selected genes, we could observe that many of the upregulated genes were involved in the cellular response to 5-OP accumulation. However, it did not appear that there was any significant oxidative stress response. The study suggests a need to reevaluate previous suppositions of the 5-OP induced oxidative stress response. Instead, we propose an alternative model to explain the possible consequences of 5-oxoprolinase deficiency based on these findings made with the yeast model.

systems biology↗

bioRxiv2025

Anti-CRISPR-mediated continuous directed evolution of CRISPR-Cas9 in human cells

Engineering CRISPR-Cas systems for improved or altered function is central to both research and therapeutic applications. Unfortunately most optimization, especially directed evolution in bacterial hosts, fails to capture the functional requirements of the complex mammalian cellular milieu, where activity is usually required. Robust strategies to enable continuous directed evolution of genome-targeting agents directly in human cells remain lacking. Here, we introduce CRISPR-MACE (Mammalian cell-enabled Adenovirus-assisted Continuous Evolution) as a foundational technology to address this need. CRISPR-MACE integrates virus-based continuous evolution with anti-CRISPR-based tunable selection to generate novel Streptococcus pyogenes Cas9 variants with both increased and decreased DNA binding capacity and nearly 1000-fold-enhanced resistance to AcrIIA4, the strongest known inhibitor of SpCas9. Notably, across independent evolution campaigns the same Cas9 gatekeeper mutation reproducibly emerged first, enabling subsequent adaptive steps along two interdependent axes of Cas9 function. In addition to advancing CRISPR technologies, this work establishes key principles and synthetic circuits for continuously evolving CRISPR-Cas systems directly in human cells. SIGNIFICANCE STATEMENTCRISPR technologies are typically engineered in bacteria, even though they must function in the far more complex environment of human cells. This gap has limited the discovery of variants with improved DNA recognition or with resistance to inhibitors that operate differently in mammalian systems. Here we establish CRISPR-MACE, a continuous evolution platform that leverages pressure from anti-CRISPR proteins to select Cas9 variants directly in human cells that have novel functions. Evolved variants show improvements in DNA binding strength and residence time, as well as striking escape from the potent Cas9 inhibitor AcrIIA4. Many anti-CRISPR proteins use distinct mechanisms, so our strategy can drive future continuous evolution campaigns in mammalian cells that expand the functional properties of genome-targeting agents.

synthetic biology↗

bioRxiv2025

Gonadal Hormone Status Dictates Neurobehavioral, Metabolic and Immunological Benefits of Ketogenic Diet in Female Mice through Gut-Metabolic-Brain Axis

The ketogenic diet (KD) is recognized for its broad therapeutic potential across metabolic, neurological, immunological, and aging-related domains; however, its efficacy and durability in females remain underexplored. This study investigated the effects of a short-term, intermittent KD on neurobehavioral function, lipid metabolism, immune response, and gut microbiota composition in sham-operated (intact) and ovariectomized (OVX, estrogen-deficient) female mice, aiming to delineate the interactions between diet and gonadal hormones. In sham females, KD reduced circulating estradiol levels and induced low-grade systemic inflammation, without producing measurable behavioral benefits. Conversely, KD exhibited reduced compulsivity, anxiety, and depression-like behaviors with improved well-being in OVX females, suggesting enhanced neurobehavioral resilience under estrogen-deficient conditions. Biochemical analyses revealed KD-induced hyperlipidemia in both groups, although the lipid load was attenuated in OVX mice. KD further decreased low-density lipoprotein cholesterol but led to uremia and histopathological evidence of hepatic steatosis and fibrosis in OVX females, despite unaltered liver function markers. 16S rRNA sequencing revealed hormone-dependent remodelling of the gut microbiota, characterised by distinct compositional shifts between the sham and OVX cohorts. Correlation analyses linked microbial alterations to improved lipid profiles and reduced anxiodepressive behaviors, implicating the gut-metabolic-brain axis in mediating the effects of KD. Collectively, these findings suggest that KD confers neurobehavioral and metabolic benefits in the absence of ovarian hormones but may also pose risks to the liver and kidneys. These results highlight ketogenic nutrition as a potential non-pharmacological strategy to mitigate menopause- and aging-associated neurobehavioral, metabolic, and immune dysfunctions through modulation of the gut microbiota.

neuroscience↗

bioRxiv2025

Scalable flow synthesis of ultrasmall inorganic nanoparticles for biomedical applications via a confined impinging jet mixer

Ultrasmall inorganic nanoparticles (sub-5 nm) have unique biomedical advantages due to rapid clearance, enhanced imaging contrast, and potent therapeutic properties. However, current synthesis methods are limited by low throughput, polydispersity, and reliance on harsh conditions such as organic solvents or high temperatures. We report a scalable, single-step aqueous synthesis using a confined impinging jet mixer (CIJM) that produces size-controlled, clinically relevant nanoparticles, including silver sulfide, silver telluride, cerium oxide, and iron oxide, under ambient conditions. The resulting nanoparticles are homogeneous, stable, and preserve their functional biological properties. We demonstrate consistent performance across scales, establishing the CIJM as a versatile and reproducible method for producing ultrasmall inorganic nanoparticles suitable for clinical translation and high-throughput biomedical applications.

bioengineering↗

bioRxiv2025

Biofuel-driven Adaptable n-type Supramolecular Wires: Mimicking Conducting Microbial Nano-filaments

We report the biofuel-driven self-assembly of a benzimidazole-pyridine platinum (II) complex into supramolecular nanowires. Phosphate promotes Pt{middle dot}{middle dot}{middle dot}Pt metallophilic stacking, whereas the pristine complex forms nanosheets dominated by {pi}-{pi} interactions. By varying phosphate denticity (adenosine/guanosine mono-, di-, and triphosphates), we tune the extent of Pt{middle dot}{middle dot}{middle dot}Pt interactions and the resulting electrical conductance of the nanowires, measured on graphene using a custom EGaIn setup. Triphosphate-templated nanowires exhibit nearly four orders of magnitude higher conductance than non-templated nanosheets. Thermopower measurements reveal a negative Seebeck coefficient, indicating LUMO-mediated electron transport and rare n-type behavior in these supramolecular assemblies. Temperature-dependent measurements show a transition from tunneling (non-templated nanosheets) to thermally activated hopping (triphosphate templated nanowires). The system is recyclable, apyrase hydrolysis disrupts the nanowires, and re-addition of phosphate restores assembly, enabling reversible conductance switching over multiple cycles. This study demonstrates a fuel-responsive, adaptive supramolecular electronic material, highlighting how controlled Pt{middle dot}{middle dot}{middle dot}Pt interactions can be exploited to program charge transport in soft, bioinspired electronic systems.

bioengineering↗

bioRxiv2025

Trehalose metabolism regulates transcriptional control of muscle development in lepidopteran insects

The connection between trehalose metabolism and insect muscle development has long been unclear. Here we demonstrate that trehalose-derived glucose flux is essential for sustaining glycolysis and maintaining cellular energetics during metamorphosis in Helicoverpa armigera. Disruption of trehalose synthesis through silencing of trehalose 6-phosphate synthase/phosphatase (TPS/TPP) or paramyosin (Prm) produced defective eclosion and alike fragmented muscle fibers. Metabolic profiling revealed broad depletion of glycolytic intermediates and cofactors consistent with elevated AMP and activation of energy-stress signalling. Transcriptome analysis also showed downregulation of the transcription factor E2F/Dp, along with reduced expression of cyclin/CDK components, indicative of cell cycle checkpoint dysregulation. E2F/Dp repression resulted in lower expression of Mef2, Prm, MHC, and other sarcomeric components, causing defective muscle development and weakened muscle architecture. Gene set enrichment analysis, gene regulatory network and promotor binding analysis confirmed E2F binding motifs within promoters of trehalose metabolism and myogenic genes, suggesting a potential metabolic-transcriptional connection. Furthermore, dietary trehalose supplementation partially rescued metabolic depletion and restored expression of E2F targets in TPS/TPP- and E2F/Dp-silenced insects. Collectively, our findings establish trehalose metabolism as a metabolic regulator that couples energy homeostasis to cell-cycle transcriptional control and muscle development.

developmental biology↗

bioRxiv2025

Jumonji-C domain containing demethylase 1 is critical for heterochromatin organization in Plasmodium falciparum

Despite the central importance of epigenetic regulation in enabling adaptation and pathogenicity of malaria parasites, mechanisms controlling heterochromatin distribution in Plasmodium falciparum are poorly understood. Here, we identified P. falciparum Jumonji C domain-containing histone demethylase 1, PfJmjC1, as a key regulator of heterochromatin. Parasites lacking PfJmjC1 are viable in vitro but display slightly reduced multiplication rates compared to wild type parasites. Interestingly, PfJmjC1 depletion leads to major heterochromatin reorganization, involving de novo heterochromatin formation over non-essential, GC-rich euchromatic genes and reduction of heterochromatin at some chromosome ends, eventually altering the 3D genome architecture. Importantly, this heterochromatin reorganization results in the deregulation of cell surface antigen expression and failure of parasites to induce gametocyte production in response to nutrient deprivation. Collectively, our findings highlight the crucial role of PfJmjC1 in regulating heterochromatin distribution and life cycle progression in this deadly pathogen.

molecular biology↗

bioRxiv2025

Phospholipids that plug the pores of cholesteryl ester transfer protein control its lipid transfer dynamics

The mechanism by which cholesteryl ester transfer protein (CETP), a key drug target in cardiovascular disease, moves lipids between lipoproteins, has remained elusive. CETP is the primary protein that regulates plasma circulating levels of lipids (within high, low, and very low-density lipoproteins. The protein, in addition to its terminal openings, has two additional openings, plugged by two phospholipids (PLs). Small molecule inhibitors targeting CETP tunnel displace PL during CETP inhibition. Here, using steered molecular dynamics simulations followed by in-vitro mutagenesis we show that CETP-bound PLs are indispensable in establishing the optimal architecture of CETP tunnel. Our structural and functional analyses revealed that lipid traversal through CETPs central tunnel is facilitated through hydrophobic interaction-mediated diffusion. PLs are critical in synchronizing domain movements of CETP while accelerating triglyceride traversal through the tunnel and their activity regulated through salt-bridge interactions. Most notably, we show for the first time that phospholipids (PLs) bound within CETPs tunnel accelerate lipid movement through a novel "gliding" mechanism, representing the first known example of a lipid regulating the movement of another. We identified conserved phenylalanine (Phe) flaps that act as a regulatory valve, opening and closing concertedly to prevent lipid backflow in the absence of an active motor. This study provides in-depth understanding of the mechanism of lipid exchange by CETP guided, and accentuated by its interaction with PLs. The conservation of these critical structural elements across the BPI/LBP family suggests that this mechanism is broadly applicable, expanding our understanding of lipid transport in this clinically significant protein class. Significance StatementThe mechanism of lipid transport by the cholesteryl ester transfer protein (CETP), a major drug target, has long been a scientific mystery. Neutral lipid exchange through CETP is dependent on the hydrophobic characteristics of the tunnel that has been exploited during inhibitor design. We provide a detailed, molecular-level explanation, showing for the first time that phospholipids (PLs), previously thought to be static plugs, are indispensable for lipid transfer. They actively accelerate lipid movement through a novel gliding mechanism, the first documented instance of a lipid regulating another. This discovery identifies new therapeutic targets for CETP inhibition. Our findings also suggest that this fundamental mechanism is conserved across a large protein family, with broad implications for understanding lipid transport and function.

biophysics↗

bioRxiv2025

A developmental transition from early neural hyperexcitability in zebrafish

Early brain development is characterized by plastic phases that play a crucial role in the establishment of functional connectivity. However, this plasticity also renders the developing brain highly sensitive to perturbations. The dynamics of the transition of the immature brain from a hyperexcitable state to a relatively stable network remains poorly understood. Using a combination of brain-wide activity mapping, behavioural and molecular analysis in response to pentylenetetrazole (PTZ), a GABAA receptor antagonist, we assessed neural hyperexcitability at different developmental stages in larval zebrafish and observed a distinct age-dependent trajectory. Specifically, we observed that early stages (4-6 dpf) exhibited high susceptibility to external perturbations, whereas by 9 dpf, both neural activity and behavioral responses were markedly attenuated. Further, upon chronic insult, rather than a cumulative increase in excitability, early life hyperexcitation events rendered the larvae resistant to subsequent induction. Put together, our work maps the temporal transition of the vertebrate brain from a state of hyperexcitability to a phase of relative resistance and has potential implications on understanding the progression of neurological conditions in the pediatric population.

neuroscience↗

bioRxiv2025

Steviol glycoside biosynthesis pathway gene expression profiling of transformed and non-transformed plant leaf tissues of Stevia rebaudiana (Bertoni)

Stevia rebaudiana Bertoni, a member of the Asteraceae family, is recognized for its sweetened leaves which are remarkably sweeter than sucrose by 200-300 times. This astounding property is because of steviol glycosides (SGs), a class of diterpenoid secondary metabolites which primarily consists of stevioside and rebaudioside A. These compounds are formed through a specific steviol glycoside (SG) biosynthetic pathway that contains several key genes. In the present work, gene expression profiling of 15 core genes of SG biosynthetic pathway, along with metabolite analysis were conducted in three groups of Stevia rebaudiana plants: In vitro regenerated non-transformed plantlets (NP), in vitro regenerated transformed plantlets (TP) via hairy root cultures using Rhizobium rhizogenes mediated transformation and Control plants (CP). Quantitative real-time PCR (qRT-PCR) results showed that in NP and TP there was upregulation of 13 genes. Both NP and TP showed downregulated SrDXR and SrCDPS in comparison to CP, whereas SrUGT74G1 had higher expression in NP than TP. HPLC chromatographic studies on SGs showed that stevioside content followed the order TP > NP > CP. These findings demonstrate that transformation enhances SG biosynthesis and support the use of genetically modified Stevia rebaudiana lines for increased natural sweetener production. Further studies are warranted to elucidate regulatory mechanisms and optimize metabolic engineering approaches. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/670226v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1615c89org.highwire.dtl.DTLVardef@10264a0org.highwire.dtl.DTLVardef@1c7935org.highwire.dtl.DTLVardef@159aea3_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗