Biology subjects

Ni, B.

Publications and source records attributed to Ni, B..

At least 19 recordsLinked to original sources

bioRxiv2026

Microbiome-mediated lauric acid turnover contributes to colonization resistance against Ralstonia in the tomato rhizosphere

Host-associated lipids shape plant-microbiome interactions, but their microbiome-mediated turnover and role in pathogen exclusion are not fully understood. In tomato, lauric acid (C12:0) occurs across root-associated compartments, and its abundance at the root-soil interface is linked to soil-dependent differences in rhizosphere community composition and Ralstonia solanacearum colonization. Lauric acid promotes Ralstonia motility and virulence in vitro while inhibiting some beneficial lauric-acid-sensitive taxa, especially Gram-positive antagonists. In disease-suppressive soils, rhizosphere communities enriched in lauric-acid-degrading taxa are associated with lower local lauric acid levels and reduced pathogen colonization, suggesting community-dependent buffering of the rhizosphere lauric acid pool alongside other protective microbiome functions. Soil perturbation, microbiome transplantation, gnotobiotic SynCom reconstruction, and isotope tracing provide convergent evidence that microbiome-mediated lauric acid turnover contributes to colonization resistance and helps explain how rhizosphere lipid chemistry influences pathogen invasion outcomes in tomato, revealing an ecologically grounded protective mechanism for pathogen management.

microbiology↗

bioRxiv2026

Density-dependent facilitation of livestock by small mammal ecosystem engineers

Small mammals and large herbivores have co-evolved in grasslands for millions of years, yet how they interplay remains unclear. Although large herbivores can significantly affect the smaller ones, the reversal effect is largely unknown. On the Qinghai-Tibetan Plateau, plateau pikas (Ochotona curzoniae) are often considered pests that compete with livestock at high densities. Using field experiments, we show that the presence of pikas facilitates weight gains of yaks (Bos grunniens) by improving vegetation composition at a moderate density level. Compared to the pika-present treatment, pika removal dramatically increased cover of the poisonous Stellera forbs by two-fold, reducing the abundance and protein content of palatable grasses and sedges, yak foraging efficiency, and yak weight gain by up to 42%. Notably, we found a humped relationship between yak weight gains and pika burrow densities in the pika-present plots; the facilitative effect of pikas on yaks was highest at about 200 burrows/ha, but shifted to a competitive effect at pika densities exceeding 400 burrows/ha. These results provide the first empirical evidence that maintaining a moderate density of small mammalian herbivores can benefit growth performance of livestock by improving vegetation composition. Our study highlights the significance of moderate populations of ecosystem-engineering small mammals in sustaining pastoral productivity in rangelands.

ecology↗

bioRxiv2025

Interaction of Carbamoyl-Phosphate Synthase 1 with Agmatinase in the Liver of Torpid Bats

Mammalian torpor imposes unique metabolic constraints, yet the mechanisms of nitrogen metabolism during this state remain unclear. In this study, we show that the urea cycle is selectively regulated rather than broadly suppressed in torpid bats. A significantly increased abundance of carbamoyl-phosphate synthase 1 (CPS1) maintained its functional capacity during torpor and arousal in Myotis ricketti. Proteomic analyses and confocal microscopy identified a specific association and co-localization between CPS1 and agmatinase (AGMAT), an ATP-independent enzyme involved in nitrogen metabolism. Co-localization of CPS1 and AGMAT was also observed in torpid Rhinolophus ferrumequinum, a phylogenetically distant species. Fluorescence resonance energy transfer (FRET) further supported an indirect CPS1-AGMAT interaction. Most urea cycle enzymes exhibited stable or only moderately reduced expression during bat torpor, and metabolic profiling demonstrated sustained nitrogen flux. Together, these findings reveal a conserved adaptive mechanism that maintains urea cycle function, potentially enhancing osmotic stability and energy efficiency during prolonged fasting and water scarcity.

zoology↗

bioRxiv2025

NPAS2 attenuates VSMC phenotypic switching in ascending thoracic aortic aneurysm via LPCAT3/PC-PUFA2S-mediated ferroptosis

Ascending thoracic aortic aneurysm (ATAA) is a life-threatening disorder with limited therapeutic options, critically linked to vascular smooth muscle cell (VSMC) phenotypic switching. Neuronal PAS Domain Protein 2 (NPAS2), a circadian rhythm-related transcription factor, regulates diverse physiological processes. However, the biological functions and underlying regulatory mechanisms of NPAS2 in VSMCs during ATAA pathogenesis remain to be elucidated. NPAS2 expression decreased in ATAA patients, PDGF-BB-treated HASMCs and BAPN-administrated mice. NPAS2 depletion facilitated VSMC phenotype switching. VSMC-specific NPAS2 knockout (NPAS2SMKO) mice exhibited aggravated ATAA. Mechanistically, NPAS2 depletion attenuates its transcriptional repression of LPCAT3, subsequently elevating the accumulation of phosphatidylcholines with two polyunsaturated fatty acyl chains (PC-PUFA2S), thereby promoting ferroptosis-induced VSMC phenotype switching and accelerating ATAA progression. Targeting NPAS2 represents a potential therapeutic strategy for ATAA treatment.

molecular biology↗

bioRxiv2024

Adaptation to cystine limitation stress promotes PDAC tumor growth and metastasis through translational upregulation of OxPPP

Cystine/cysteine is critical for antioxidant response and sulfur metabolism in cancer cells and is one of the most depleted amino acids in the microenvironment of pancreatic ductal adenocarcinoma (PDAC). The effects of cystine limitation stress (CLS) on PDAC progression are poorly understood. Here we report that adaptation to CLS (CLSA) promotes PDAC cell proliferation and tumor growth through translational upregulation of the oxidative pentose phosphate pathway (OxPPP). OxPPP activates the de novo synthesis of nucleotides and fatty acids to support tumor growth. On the other hand, CLSA-mediated lipidomic reprogramming depends on triacylglycerides synthesis and lipid droplet formation to mitigate lipotoxicity. Through drug screening, we identify lomitapide as an inhibitor of CLSA PDAC tumor growth and a potent sensitizer of chemotherapy. Lomitapide inhibits triacylglycerides synthesis to interfere with CLSA and chemotherapy-induced lipidomic reprogramming. Taken together, we demonstrate that CLSA promotes PDAC tumor growth through metabolic reprogramming and lomitapide could be used to target the dysregulated lipid metabolism in PDAC.

cancer biology↗

bioRxiv2024

Principles of nutrition-dependent root-microbiome engineering for regulating crop yield via live microbial inoculants

As the second genome, host-associated microbiota can enhance the functions of host immune systems, improve host nutrient availability and acquisition capacity, and increase host resistance to abiotic stress. Constructing host-associated microbiomes by applying various bioinoculants has become an attractive tool for promoting human health and increasing food production. However, despite their promising properties, the efficacy of bioinoculants vary significantly in actual field and clinical practices. Understanding the global design principles that shape the outcomes of interactions between bioinoculants and target host-microbiome symbionts remains a considerable challenge. In this study, we used a wheat production system as a case study to quantitatively understand how soil nutrient status impacts the establishment of host-microbiome interaction networks and their subsequent interactions with external bioinoculants. We found that soil organic carbon, one of the most general soil properties for global crop productivity and resilience, could affect the outcome of bioinoculant applications in wheat production systems, which led to functional instability in bioinoculant application outcomes. The results of this study significantly improved our understanding of the global design principles of nutrition-dependent root-microbiome engineering for regulating crop yield via the application of live microbial inoculants and provide theoretical guidance for bioinoculant applications in agricultural practice.

microbiology↗

bioRxiv2024

Plasticity and Dynamics of Hematopoietic Cells within Bone Marrow Microenvironment in Leukemia

Extensive research has been conducted on the plasticity of malignant cells and nonmalignant cells in solid tumor. However, the plasticity of bone marrow hematopoietic cells in leukemia have remained largely unexplored. In this study, we aimed to investigate cell changings in hematopoietic cells through lineage tracing across various types of leukemias. We had compiled a landscape of leukemia and constructed phylogenetic trees of hematopoietic cells through utilizing massively parallel scRNA-seq data, mtDNA mutation and SNP analysis. Based on the observed cell changings, we identified several types of cell changings, including transdifferentiation, dedifferentiation, and state transition, except for differentiation and expansion. In AML and CMML, GMPs and neutrophils showed a higher potential for transferring to other cell types. In BPDCN, pDCs were less prone to switching to other cell types, while T cells demonstrated high plasticity. In B-ALL and B-CLL, B-ALL blast cells and B-CLL blast cells emerged at the most dynamic state. The dynamics of hematopoietic cells in AML, BPDCN and ALL changed along with the clinical process. Extrinsic factors within the leukemia microenvironment may influence the cell changings. Regulons encountered an intermediate cell state during the process of transition to myeloid cells and erythroid cells. We also found a correlation between B-common blast cells and T cells, suggesting a potential transition from B lymphoblastic leukemia to T lymphoblastic leukemia. In conclusion, our study unveiled the distinct plasticity and dynamics of hematopoietic cells in various types of leukemia. This sheds light on the possibility of targeting cell changes as a new strategy for leukemia treatment and improving current immunotherapy.

bioinformatics↗

bioRxiv2024

Physics and physiology determine strategies of bacterial investment in flagellar motility

Regulatory strategies that allow microorganisms to balance their investment of limited resources in different physiological functions remain poorly understood, particularly for numerous cellular functions that are not directly required for growth. Here, we investigate the allocation of resources to flagellar swimming, the most prominent and costly behavior in bacteria that is not directly required for growth. We show that the dependence of motile behavior on gene expression in Escherichia coli is determined by the hydrodynamics of propulsion, which limits the ability of bacteria to increase their swimming by synthesizing more than a critical number of flagellar filaments. Together with the fitness cost of flagellar biosynthesis, this defines the physiologically relevant range of investment in motility. Gene expression in all E. coli isolates tested falls within this range, with many strains maximizing motility under nutrient-rich conditions, particularly when grown on a porous medium. The hydrodynamics of swimming may further explain the bet-hedging behavior observed at low levels of motility gene expression.

microbiology↗

bioRxiv2024

Experimental evolution of a reduced bacterial chemotaxis network

Chemotaxis allows bacteria to follow chemical gradients by comparing their environment over time and adjusting their swimming behavior accordingly. The chemotaxis signaling pathway is highly conserved among all chemotactic bacteria. The system comprises two modules: one for environmental sensing and signal transduction toward the flagellar motor, and the other for adapting to the constant level of background stimulation and providing short-term memory for temporal comparisons. Previous experimental analysis and mathematical modeling have suggested that all components of the paradigmatic chemotaxis pathways in Escherichia coli are essential. This indicates that it may contain a minimal set of protein components necessary to mediate gradient sensing and behavioral response. To test this assumption, here we subjected strains carrying deletions in chemotaxis genes to experimental laboratory evolution. We observed that the core components of the chemotaxis pathway are indeed essential. However, the absence of individual auxiliary pathway proteins, including the adaptation enzymes that are conserved in a vast majority of bacteria, and the phosphatase, could be compensated for to varying degrees by changes in other pathway components. Our results suggest that the experimental evolution of these deletion strains has led to the emergence of alternative strategies for bacterial chemotaxis, demonstrating the surprisingly rapid evolvability of this signaling network.

microbiology↗

bioRxiv2023

Validation of human telomere length trans-ancestry meta-analysis association signals identifies POP5 and KBTBD6 as novel human telomere length regulation genes

Telomere length genome-wide association studies (GWAS) have become well-powered to detect novel genes in telomere length regulation. However, no prior work has validated these putative novel genes to confirm the contribution of GWAS loci to telomere length regulation. We conducted a trans-ancestry meta-analysis of 211,369 individuals. Through enrichment analyses of chromatin state and cell-type heritability we identified blood and immune cells as the most relevant cell type to examine telomere length association signals. We validated specific GWAS associations by overexpressing KBTBD6, a component of an E3 ubiquitin ligase complex, and POP5, a component of the Ribonuclease P/MRP complex, and demonstrating that both lengthened telomeres as predicted by our statistical analyses. CRISPR/Cas9 deletion of the predicted causal regions of these association peaks in K562 immortalized blood cells reduced expression of these genes, demonstrating that these loci are related to transcriptional regulation of KBTBD6 and POP5, respectively. Together our results demonstrate the utility of telomere length GWAS in the identification of novel telomere length regulation mechanisms and highlight the importance of the proteasome-ubiquitin pathway in telomere length regulation.

genetics↗

bioRxiv2023

Attractant and repellent induce opposing changes in the chemoreceptor four-helix bundle ligand-binding domain

Motile bacteria navigate toward favorable conditions and away from unfavorable environments using chemotaxis. Mechanisms of sensing attractants are well understood, however molecular aspects of how bacteria sense repellents have not been established. Here, we identified malate as a repellent recognized by the MCP2021 chemoreceptor in a bacterium Comamonas testosteroni and showed that it binds to the same site as an attractant citrate. Binding determinants for a repellent and an attractant had only minor differences, and a single amino acid substitution in the binding site inverted the response to malate from a repellent to an attractant. We found that malate and citrate affect the oligomerization state of the ligand-binding domain in opposing way. We also observed opposing effects of repellent and attractant binding on the orientation of an alpha helix connecting the sensory domain to the transmembrane helix. We propose a model to illustrate how positive and negative signals are generated and transduced across the membrane and built chimera proteins to illustrate a universal nature of the transmembrane signaling by the repellent.

microbiology↗

bioRxiv2022

The functional impact of rare variation across the regulatory cascade

Each human genome has tens of thousands of rare genetic variants; however, identifying impactful rare variants remains a major challenge. We demonstrate how use of personal multi-omics can enable identification of impactful rare variants by using the Multi-Ethnic Study of Atherosclerosis (MESA) which included several hundred individuals with whole genome sequencing, transcriptomes, methylomes, and proteomes collected across two time points, ten years apart. We evaluated each multi-omic phenotypes ability to separately and jointly inform functional rare variation. By combining expression and protein data, we observed rare stop variants 62x and rare frameshift variants 216x as frequently as controls, compared to 13x to 27x for expression or protein effects alone. We developed a Bayesian hierarchical model to prioritize specific rare variants underlying multi-omic signals across the regulatory cascade. With this approach, we identified rare variants that exhibited large effect sizes on multiple complex traits including height, schizophrenia, and Alzheimers disease.

genomics↗

bioRxiv2022

PanGu Drug Model: Learn a Molecule Like a Human

Recent achievements in large-scale pre-trained models like GPT-3 and PanGu- showed amazing performances in many downstream tasks, which makes AI friendlier toward industrial users. Deep learning has been recognized as the most promising technology for pharmaceuticals, a powerful molecule pre-trained model could save researchers tons of time. In chemistry classes, the students learn two molecule representations, the molecular formula and the structure formula, and learn to translate them from one way to the other. Inspired by this, we developed a novel deep learning architecture using a graph-to-sequence asymmetric conditional variational autoencoders, called PanGu Drug Model, which can appropriately characterize the molecule from both representations and improve the performance of downstream drug discovery tasks. After pretrained with 1.7 billion small molecules, our proposed model achieved the state-of-the-art results in 20 drug discovery tasks, such as molecule property prediction (predict ADMET properties, compound-target interactions, drug-drug interactions and chemical reaction productivity), molecule generation and molecule optimization. A new drug screening library of 100 million drug-like small molecules with 99.68% novelty was generated by PanGu molecule generator, which could efficiently produce novel compounds with similar physiochemical properties to given distribution, this library could be used to supplement existing compound databases. In addition, PanGu molecule optimizer could optimize the chemical structures of starting molecule with improved molecular property of interest. An automatic multi-objective optimization web application implemented by PanGu Drug Model is available at http://www.pangu-drug.com/.

biochemistry↗

bioRxiv2021

Application of a simple device for "attracting" and "trapping" glioma cells in situ

Glioblastoma multiforme (GBM) is the most malignant adult brain tumor. The current adjuvant therapies for GBM are disappointing, which are based on cytotoxicity strategy. Thus, other ways should be explored to improve the curative effect. According to the strong invasive ability of GBM cells, we assume a new treatment strategy for GBM by developing a new cell trap device (CTD) with some kind of "attractive" medium loaded in it to attract and capture the tumor cells. The in vitro experiment showed that Hepatocyte Growth Factor (HGF) presented stronger chemotaxis on C6 and U87 cell line than the Epidermal Growth Factor (EGF) and Fibroblast Growth Factor (FGF). A simple in vitro CTD loaded with HGF was made and in vivo experiments results showed that HGF successfully attracted tumor cells from tumor bed in situ into the CTD. This study proposes the new strategy for GBM treatment of "attract and trap" tumor cells is proved to be feasible.

neuroscience↗

bioRxiv2021

Jasmine: Population-scale structural variant comparison and analysis

The increasing availability of long-reads is revolutionizing studies of structural variants (SVs). However, because SVs vary across individuals and are discovered through imprecise read technologies and methods, they can be difficult to compare. Addressing this, we present Jasmine (https://github.com/mkirsche/Jasmine), a fast and accurate method for SV refinement, comparison, and population analysis. Using an SV proximity graph, Jasmine outperforms five widely-used comparison methods, including reducing the rate of Mendelian discordance in trio datasets by more than five-fold, and reveals a set of high confidence de novo SVs confirmed by multiple long-read technologies. We also present a harmonized callset of 205,192 SVs from 31 samples of diverse ancestry sequenced with long reads. We genotype these SVs in 444 short read samples from the 1000 Genomes Project with both DNA and RNA sequencing data and assess their widespread impact on gene expression, including within several medically relevant genes.

genomics↗

bioRxiv2020

Benchmarking challenging small variants with linked and long reads

Genome in a Bottle (GIAB) benchmarks have been widely used to help validate clinical sequencing pipelines and develop new variant calling and sequencing methods. Here, we use accurate linked reads and long reads to expand the prior benchmarks in 7 samples to include difficult-to-map regions and segmental duplications that are not readily accessible to short reads. Our new benchmark adds more than 300,000 SNVs, 50,000 indels, and 16 % new exonic variants, many in challenging, clinically relevant genes not previously covered (e.g., PMS2). For HG002, we include 92% of the autosomal GRCh38 assembly, while excluding problematic regions for benchmarking small variants (e.g., copy number variants and reference errors) that should not have been in the previous version, which included 85% of GRCh38. By including difficult-to-map regions, this benchmark identifies eight times more false negatives in a short read variant call set relative to our previous benchmark.We have demonstrated the utility of this benchmark to reliably identify false positives and false negatives across technologies in more challenging regions, which enables continued technology and bioinformatics development.

genomics↗

bioRxiv2020

Targeted nanopore sequencing by real-time mapping of raw electrical signal with UNCALLED

ReadUntil sequencing allows nanopore devices to selectively eject individual reads from the pore in real-time. This could enable purely computational targeted sequencing, however most mapping methods require basecalling, which is computationally intensive. Here we present UNCALLED (github.com/skovaka/UNCALLED), an open-source mapper that rapidly matches streaming nanopore current signals to a reference sequence. UNCALLED probabilistically considers k-mers that the signal could represent, and then prunes the candidates based on the reference encoded within an FM-index. We used UNCALLED to deplete sequencing of known bacterial genomes within a metagenomics community, enriching the remaining species by 4.46 fold. UNCALLED also enriched 148 human genes associated with hereditary cancers to 29.6x coverage using one MinION flowcell, enabling accurate detection of SNPs, indels, structural variants (SVs), and methylation in these genes. Twice as many SVs were detected compared to 50x coverage Illumina sequencing, all verified by whole-genome nanopore and PacBio HiFi sequencing.

genomics↗

bioRxiv2019

A pentylenetetrazole-induced kindling zebrafish larval model for evoked recurrent seizures

BackgroundTransient pentylenetetrazol (PTZ) treatment on zebrafish larvae has been widely accepted a promising animal model for human epilepsy. However, this model is not ideal due to its acuteness and lack of recurrent seizures, which are the key feature of epilepsy in human disease. It is important to develop a more sensitive zebrafish model for epilepsy with well-controlled, predictable, recurrent seizures.\n\nNew MethodThe new method includes an experimental setup and a treatment protocol. The setup tracks the locomotion activity of up to 48 larvae simultaneously, while a visual stimulus can be presented to each of the 48 animals individually. The protocol treated the larvae through a water bath in 5 mM PTZ while being stimulated with rotating grating stimuli for 1 hour/day from 5 to 7 days postfertilization.\n\nResultsThe setup captured the locomotion activity of zebrafish larvae during visual stimulation. The new protocol generated recurrent responses after flashing lights 4 hours post PTZ treatment. The effects could be suppressed by the anti-epileptic drug valproic acid. The characteristics of the visual stimulus play a major role in this kindling model.\n\nComparisons with Existing MethodsWe compared the proposed method with the transient PTZ model and confirmed that the flashing-light-evoked recurrent seizure is a new feature in addition to the transient changes.\n\nConclusionsThe new method generated non-drug-triggered predictable recurrent seizures in response to intermittent photic stimulation in zebrafish larvae and may serve as a sensitive method for anti-epileptic drug screening or a new research protocol in epilepsy research.

neuroscience↗