Biology subjects

Fu, X.

Publications and source records attributed to Fu, X..

At least 55 records · Page 3Linked to original sources

bioRxiv2025

Developmentally-specific physiological and metabolic responses support drought resilience in switchgrass and constrains biofuel yield

Switchgrass (Panicum virgatum) is a promising bioenergy crop due in part to its resilience to drought stress. However, the significance of drought timing remains poorly understood, both from a plant biology perspective and its impact on downstream biofuel production. This study determines the developmental stage-specific physiological and metabolic responses of switchgrass to drought stress and its implications for biofuel production using a custom-built programmable irrigation system. Vegetative, flowering, and senescence-stage drought significantly reduced CO2 assimilation, and stomatal conductance without affecting biomass yield. Metabolic profiling revealed significant accumulation of glucose, fructose, quinic acid, shikimate and GABA during vegetative-stage drought, while flowering and senescence stages exhibited limited metabolic changes. Similarly, specialized metabolites also displayed distinct developmental patterns, with vegetative-stage drought driving the most pronounced metabolic alterations. Thermochemically-treated and hydrolyzed switchgrass biomass from vegetative-stage drought showed elevated lignocellulose-derived compounds and saponins with the latter most positively correlating with fermentation lag times. Conversely, senescence-stage drought enhanced ethanol yields while lowering saponin levels in the hydrolysates. While vegetative-stage drought enhanced physiological resilience, it compromises downstream biofuel production by introducing fermentation inhibitors, particularly saponins.

plant biology↗

bioRxiv2025

Artemisia Database: A Comprehensive Resource for Gene Expression and Functional Insights in Artemisia annua

Artemisia annua is renowned for producing artemisinin, a compound that revolutionized malaria treatment and holds therapeutic promise for other diseases, including cancer and diabetes. However, low natural yields of artemisinin remain a major bottleneck, necessitating a deeper understanding of the genetic and regulatory networks involved in its biosynthesis. Although several transcriptomic studies on A. annua exist, they are often limited in scope, and a comprehensive, tissue-resolved gene expression resource has been lacking. Here, we present the Artemisia Database (Artemisia-DB)--a high-resolution expression atlas constructed from an extensive integration of publicly available RNA-seq datasets. The database provides transcript- and gene-level abundance estimates across major tissues and includes functional annotations such as Gene Ontology (GO) terms, KEGG pathways, and InterPro domains. As a case study, we investigated the coexpression profile of HMGR (3-hydroxy-3-methylglutaryl- CoA reductase), a key enzyme in the mevalonate pathway and an early step in artemisinin biosynthesis. Coexpression analysis in leaf tissue revealed a subset of Auxin Response Factor (ARF) transcription factors strongly correlated to HMGR. This finding suggests a potential regulatory link between auxin signaling and artemisinin biosynthesis, providing new hypotheses for functional validation. Artemisia-DB is freely accessible at https://artemisia-db.com and offers an interactive interface for exploring expression data, functional annotations, transcription factors, CRISPR targets, and more. By combining high-quality transcriptome data with regulatory and functional insights, Artemisia-DB serves as a valuable resource for the plant research community and facilitates deeper investigation into the transcriptional dynamics and specialized metabolism of A. annua.

bioinformatics↗

bioRxiv2025

Whole-brain chemosensory responses of both C. elegans sexes

Sexually-dimorphic neural circuits play a critical role in shaping sex-specific animal behaviors. Maps of the structural dimorphisms in these circuits have been explored by analyzing "synaptic connectomes", electron micrograph reconstructions of synaptic connectivity. Nevertheless, recent studies in the model organism C. elegans have shown little to no correlation between the synaptic connectome and dynamic neural activity. Therefore, the extent of sexual dimorphism in functional neural activity remains unknown. To determine the extent of functional sexual-dimorphisms in C. elegans we compared activity, neuron-by-neuron, across all neurons in the heads of both sexes. To sample a broad view of responses to different sensory modalities, we tested a diverse panel of ethologically-relevant olfactory, gustatory, and chemical stimuli, representing both attractive and aversive cues. We found that nearly every sensory neuron responded dimorphically to at least one cue and monomorphically to other cues, indicating that sexually-dimorphic circuits are pervasive and stimulus dependent. This dimorphic and monomorphic activity was present to a lesser extent in downstream interneurons and even less so in motoneurons, implicating sensory neurons as the primary source and location of sexually-dimorphic activity. Comparing the functional activity we measured to the published synaptic connectomes of both sexes revealed that sexual dimorphism in functional connectivity was distinct from and complementary to sexual dimorphism in synaptic connectivity. Our results provide a first-of-its-kind comparison of whole-brain dynamics between sexes at the level of single neurons, serving as an extensive resource for further investigations of functional sex differences.

neuroscience↗

bioRxiv2025

A computational framework for mapping isoform landscape and regulatory mechanisms from spatial transcriptomics data

Transcript diversity including splicing and alternative 3 end usage is crucial for cellular identity and adaptation, yet its spatial coordination remains poorly understood. Here, we present SPLISOSM (SpatiaL ISOform Statistical Modeling), a computational framework for detecting isoform-resolution patterns from spatial transcriptomics data. SPLISOSM leverages multivariate testing to account for spot- and isoform-level dependencies, demonstrating robust and theoretically grounded performance on sparse data. In the mouse brain, we identify over 1,000 spatially variable transcript diversity events, primarily in synaptic signaling pathways linked to neuropsychiatric disorders, and uncover both known and novel regulatory relationships with region-specific RNA binding proteins. We further show that these patterns are evolutionarily conserved between mouse and human prefrontal cortex. Analysis of human glioblastoma highlights pervasive transcript diversity in antigen presentation and adhesion genes associated with specific microenvironmental conditions. Together, we present a comprehensive spatial splicing analysis in the brain under normal and neoplastic conditions.

bioinformatics↗

bioRxiv2025

Uev1A counteracts oncogenic Ras stimuli in both polyploid and diploid cells

Oncogenic Ras is known to induce DNA replication stress, leading to cellular senescence or death. In contrast, we found that it can also trigger polyploid Drosophila ovarian nurse cells to die by inducing aberrant division stress. To explore intrinsic protective mechanisms against this specific form of cellular stress, here we conducted a genome-wide genetic screen and identified the E2 enzyme Uev1A as a key protector. Reducing its expression levels exacerbates the nurse cell death induced by oncogenic Ras, while overexpressing it or its human homologs, UBE2V1 and UBE2V2, mitigates this effect. Although Uev1A is primarily known for its non-proteolytic functions, our studies demonstrate that it collaborates with the E3 APC/C complex to mediate the proteasomal degradation of Cyclin A, a key cyclin that drives cell division. Furthermore, Uev1A and UBE2V1/2 also counteract oncogenic Ras-driven tumorigenesis in diploid cells, suppressing the overgrowth of germline tumors in Drosophila and human colorectal tumor xenografts in nude mice, respectively. Remarkably, elevated expression levels of UBE2V1/2 correlate with improved survival rates in human colorectal cancer patients harboring oncogenic KRAS mutations, indicating that their upregulation could represent a promising therapeutic strategy.

cell biology↗

bioRxiv2025

A biGWAS strategy reveals the genetic architecture of the interaction between wheat and Blumeria graminis f. sp. tritici

BackgroundWheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most significant diseases affecting global wheat production. Breeding for disease resistance (R) genes against Bgt often follows a boom-bust cycles, where cultivars with effective resistance are widely deployed on an expanding area until virulence emerges in the avirulence (Avr) pathogen population. While extensive effort has been devoted to identifying and cloning R genes, Avr genes remain relatively understudied, limiting our understanding of R-Avr interactions. That said, understanding R-Avr interactions is crucial for developing durable resistance strategies. ResultsWe conducted whole genome sequencing on 245 Bgt isolates collected from major wheat-growing regions in China, identifying 120 genetically unique isolates. Each of these unique isolates was inoculated and phenotyped on a diverse panel of wheat germplasm. Through Genome-Wide Association Analysis (GWAS) in both Bgt and wheat, we identified 65 Avr loci and 251 R loci overlapping with nine and eight cloned Avr or R genes, respectively. On average, each isolate carries eight Avr alleles, ranging from one to 17. Little geographical preference for Avr alleles or their combinations was observed, suggesting that disease resistance breeding against this pathogen should be coordinated at the national level. The level of resistance level is positively correlated with the number of R alleles carried by a wheat line, and the average frequency of an R allele is 2% among the wheat panel, indicating the potential for accumulating R alleles in breeding programs. We mapped 212 R-Avr interactions based on joint GWAS using both plant and pathogen genomes and cross-species epistasis, where a network of interactions was formed between wheat and Bgt. These interactions indicate that pyramiding five major R loci has the potential to confer resistance to half of the Avr loci. As a proof of concept, we successfully verified two previously described R-Avr pairs using tobacco experiments. Furthermore, we provided molecular validation evidence for three new Avr genes, including Bgt-50651, BgtE-5826 and BgtE-20009, and two new R-Avr interactions. Among them, Bgt-50651 interacts with Pm1a, Pm2a, and another unidentified R gene located near the Pm6/Pm52 interval. ConclusionOur study provides a framework for understanding the genetic interaction between plants and pathogens. The discovery of novel R/Avr loci and their complex interaction network underscores the need to integrate crop and pathogen genetic background, particularly the R/Avr allele composition, into breeding program design. These findings have significant implications for developing durable resistance strategies in wheat alongside offering valuable insights into the broader dynamics of plant-pathogen interactions.

genomics↗

bioRxiv2025

Nanosecond pulsed electric field precisely manipulates cytoplasmic Ca2+ oscillations during oocyte activation

Oocyte activation deficiency (OAD) is a primary cause of fertilization failure following intracytoplasmic sperm injection (ICSI), a problem that can potentially be overcome through artificial oocyte activation (AOA). However, concerns persist regarding the safety and efficacy of AOA techniques in clinical practice. In this study, nanosecond pulsed electric field (nsPEF) is proposed as a safe and controllable method for oocyte activation in vitro by precisely manipulating Ca2+ signaling in the ooplasm. Mouse oocytes collected from oviducts were exposed to nsPEF stimulation at varying intensities to induce distinct Ca2+ signaling patterns. Subsequently, these oocytes underwent parthenogenetic activation and were cultured to assess developmental potential up to the blastocyst stage. The sperm-initiated physiological Ca2+ oscillations are successfully mimicked by one series of Ca2+ signals induced by nsPEF at low or medium intensities, and improve activation efficiency and developmental potential compared to calcium ionophore A23187. Low-intensity nsPEF pulses mediated repetitive extracellular Ca2+ influx in a non-invasive, electro-permeable manner. Medium-intensity nsPEF stimulation triggered periodic Ca2+ release from the endoplasmic reticulum (ER) via the PIP2-IP3-IP3R pathway, producing physiological-like Ca2+ oscillations. The non-invasive nsPEF method ensures safe oocyte activation by preserving cellular integrity and minimizing stress responses. The efficacy of nsPEF in precisely manipulating Ca2+ signaling patterns was further validated in human unfertilized oocytes. Our findings present a novel AOA approach with enhanced safety and efficacy, especially for patients experiencing repeated fertilization failures. It is anticipated that nsPEF is emerging as a promising technology for addressing male infertility issues, and may offer a potential alternative fertility treatment, bypassing sperm for initiation of oocyte activation.

developmental biology↗

bioRxiv2025

A new class of OLD family ATPases functions in cell cycle progression in thermoacidophilic archaea

Overcoming lysogenization defect (OLD) proteins are diverse ATPases-nucleases functioning in antiphage defense in bacteria. However, the role of these proteins in archaea is currently unknown. Here, we describe a new class of archaeal OLD family ATPases and show that they do not appear to be involved in antiviral defense but play an essential role in cell cycle progression. The gene in Saccharolobus islandicus REY15A, named as Cran1 (Cell cycle related ATPase and nickase 1), cannot be deleted and exhibits cyclic expression patterns, with a peak expression during the transition from M-G1 to S cell cycle phase. Cran1 overexpression leads to significant growth retardation, cell size enlargement, and increased cellular DNA content. Cran1 displays potent nickase and ATPase activities in vitro, with the nickase activity being dependent on the presence of the ATPase domain. Notably, Cran1 copurifies with chromatin-associated proteins, such as Cren7 and a histone deacetylase homolog, suggesting its involvement in chromatin-related activities. Collectively our results suggest that Cran1 plays an important role in cell cycle progression, revealing a novel function of OLD family proteins.

microbiology↗

bioRxiv2025

The characteristic of epithelial-specific phenotypes and immunosuppressive microenvironment in the context of tumour budding in colorectal cancer

BackgroundTumour budding (TB), defined as a small cluster of up to four cells at the invasive front of the tumour, is a well-established independent and robust prognostic biomarker in colorectal cancer (CRC). This is strongly associated with adverse clinicopathological features and poor survival outcomes. Despite its clinical relevance, the precise underlying mechanism responsible for TB phenomenon remains unclear. MethodsMulti-omic approaches from bulk, regional GeoMx and Spatial Molecular Imager (SMI) RNA were used to identify the underlying mechanism of TB and its possible correlation with tumour microenvironment (TME) in CRC tissue. The results were validated using immunohistochemistry (IHC) and multiplex immunofluorescence (mIF) staining. ResultsPatients with high TB experience worse outcomes and associate with adverse clinical factors across two independent CRC cohorts. Bulk and regional RNA expression analyses reveal that tumours with high TB are significantly enriched for TNF- and TGF-{beta} signatures in both cohorts. Single cell CosMx SMI analysis confirmed TB cells exhibit higher expression of these signatures than adjacent invasive edge tumour cells. Elevated cyclinD1 expression was also observed within TB, and high cyclinD1 levels tend to experience poorer CRC prognosis. Furthermore, regional bulk RNA expression within the non-tumour (PanCK-) invasive edge areas demonstrated that tumours exhibiting high TB revealed the significantly differential expressions of immune-related genes (e.g. CD3, NKG7, IL6, CXCR6, CD47, IFNAR1 and VSIR). Single cell CosMx SMI analysis revealed that cancer-associated fibroblasts (CAFs) were physically the closest cells to TB cells. This spatial proximity was confirmed at the protein level using mIF, where the distance from TB to CD68+ macrophages predicted significantly poorer CRC outcomes. ConclusionThis multi-omic study confirms the prognostic significance of TB in CRC patients across two independent cohorts. Our findings highlight that TNF- and TGF-{beta} signalling play a crucial role in budding cells development by regulating cyclinD1. Furthermore, the transcriptomic analysis reveals an immunosuppressive niche characterised by reduced immune activity and close spatial interactions with CAFs and macrophages Ultimately, this study provides valuable insight into TBs underlying mechanism and its complex interactions within the TME. This could provide a foundation for developing targeted therapeutic strategies in CRC.

cancer biology↗

bioRxiv2025

A Cancer-Specific Antigen Drives Histone Acetylation by Stabilizing the Acetyltransferases

Histone acetylation is a critical epigenetic modification that regulates gene expression by modulating chromatin structure and function. Histone acetyltransferases are essential for maintaining acetylation homeostasis and the disruption of this balance can lead to aberrant gene expression and cancer development. Here, we describe that the cancer-specific protein MAGE-A10 increases cellular histone acetylation by stabilizing essential histone acetyltransferases KAT2A and KAT2B. The aberrant expression of MAGE-A10 in tumors prevents the degradation of KAT2A/2B through p62-mediated autophagy. Mechanistically, MAGE-A10 antagonizes the binding of KAT2A/2B with the E3 ubiquitin ligase complex CUL4A-DDB1, thereby decreasing the formation of their K63-linked ubiquitination. Furthermore, KAT2A enhances the transcription of the MAGE-A10 gene, forming a positive feedback loop that contributes to tumorigenesis. These findings provide insights into the molecular mechanisms hijacked in cancer that drive perturbed histone acetylation and suggest potential therapeutic strategies.

cancer biology↗

bioRxiv2025

Dietary Menaquinone-9 Supplementation Does Not Influence Bone Tissue Quality or Bone Mineral Density in Mice

Vitamin K has been implicated in skeletal health because vitamin K-dependent proteins are present in bone. While there are multiple forms of vitamin K, most research has focused on phylloquinone, which is found mainly in plant-based foods, and its metabolite menaquinone-4 (MK4). However, there are additional forms of vitamin K that are bacterially produced that appear to influence bone health but have not yet been studied extensively. Herein, we evaluated the effects of menaquinone-9 (MK9), a bacterially produced form of vitamin K on bone tissue quality and density in young mice. Four-week-old male (n=32) and female (n=32) C57BL/6 mice were supplemented with 0.06 mg/kg diet or 2.1 mg/kg diet of MK9 for 12 weeks. During week 11, a sub-group of mice (n=7/sex/group) received daily deuterium-labeled MK9 to trace its metabolic fate in bone. Liver MK4 and MK9 were significantly higher in mice fed 2.1 mg MK9/kg compared to those receiving 0.06 mg MK9/kg, regardless of sex (all p [≤] 0.017). MK4 was the only vitamin K form detected in bone, with 63-67% of skeletal MK4 in mice fed 2.1 mg MK9/kg derived from deuterium-labeled MK9. Femoral tissue strength, maximum bending moment, section modulus, and bone mineral density did not differ significantly across diet groups in either sex (all p[≥]0.083). Cross-sectional area (p=0.003) and moment of inertia (p=0.001) were lower in female mice receiving 2.1 mg MK9/kg compared to those receiving 0.06 mg MK9/kg, but no differences were found in male mice. Higher bone MK4 concentrations did not correlate with higher bone tissue quality or density. Despite dietary MK9 being a dietary precursor to MK4 in bone, dietary MK9 supplementation did not affect bone tissue quality or bone mineral density. Lay summaryMost research about vitamin K and bone health has focused on phylloquinone, the plant-based vitamin K form, and its metabolite menaquinone-4. Because interest in bacterially produced forms of vitamin K, which are abundant in the intestinal microbiome, is growing, we evaluated the effect of menaquinone-9 (a bacterially-produced form of vitamin K) on skeletal health. We supplemented mice with low and high doses of menaquinone-9 and also used stable-isotope labeled menaquinone-9 to trace its conversion to menaquinone-4 in bone. We found menaquinone-9 served as a precursor to menaquinone-4 in bone, but menaquinone-9 supplementation did not improve bone health.

physiology↗

bioRxiv2025

Toti: an integrated multi-omics database to decipher the epigenetic regulation of gene expression in totipotent stem cells

Totipotent cells (TSCs), the origin of mammalian life and foundation to early mammalian embryogenesis, are characterized by the highest differentiation capacity and extensive developmental potential. However, none of the existing embryonic databases have provided epigenetic and transcriptomic resources on totipotency, greatly limiting our understanding of the mechanisms governing the establishment and exit of totipotency. Here, we present Toti, a pioneering multi-omics database exclusively developed for totipotency, covering in vivo, in vitro and genome-edited human and mouse embryonic TSCs, TSC-like cells, pluripotent cells (PSCs), and embryos spanning preimplantation stages, with a total of 8,265 samples. Toti facilitates an in-depth exploration of the molecular mechanisms underlying totipotency by offering Search, Browse and Analysis modules available at http://toti.zju.edu.cn/.

developmental biology↗

bioRxiv2024

A multi-tissue developmental gene expression atlas towards understanding the biological basis of phenotypes in sheep

Sheep (Ovis aries) represents one of the most important livestock species for animal protein and wool production worldwide. However, little is known about the genetic and biological basis of ovine phenotypes, particularly for those of high economic value and environmental impact. Here, by generating and integrating 1,413 RNA-seq samples from 51 distinct tissues across 14 developmental time points, representing early prenatal, late prenatal, neonate, lamb, juvenile, adult, and elderly stages, we built a high-resolution developmental Gene Expression Atlas (dGEA) in sheep. We observed dynamic patterns of gene expression and regulatory networks across tissues and developmental stages. When harnessing this resource for interpreting genomic associations of 48 monogenetic and 12 complex traits in sheep, we found that genes upregulated at prenatal developmental stages played more important roles in shaping these phenotypes than those upregulated at postnatal stages. For instance, genetic associations of crimp number, mean staple length (MSL), and individual birth weight were significantly enriched in the prenatal rather than postnatal skin and immune tissues. By comprehensively integrating fine-mapping results and the sheep dGEA, we identified several key genes associated with complex traits in sheep, such as SOX9 (associated with MSL), GNRHR (associated with litter size at birth), and PRKDC (associated with live weight). These results provide novel insights into the gene regulatory and developmental architecture underlying ovine phenotypes. The dGEA (https://sheepdgea.njau.edu.cn/) will serve as an invaluable resource for sheep developmental biology, genetics, genomics, and selective breeding.

genetics↗

bioRxiv2024

Dissecting the Contribution of Transposable Elements to Interphase Chromosome Structure

Transposable elements (TEs) occupy nearly half of the human genome and play diverse biological roles. Despite their abundance, the extent to which TEs contribute to three-dimensional (3D) genome structure remains unclear. To investigate this, we developed te_hic, a computational pipeline that integrates genomic data with chromatin interactions. Our analysis reveals that TE sequences are responsible for 3D genome structure in interphase nuclei. This phenomenon is mediated by the recruitment of specific transcription factors to TEs, which enables both the formation and disruption of chromatin contacts. We computationally identified known contact-forming proteins (CTCF, RAD21, SMC3) and breaking proteins (RNF2), as well as novel candidate contact-formers (SMARCA4, MAFK). Knockdown of the predicted contact-formers SMARCA4 and MAFK decreased contacts and loops at and between TEs. Notably, SMARCA4 knockdown selectively reduced short-range contacts, highlighting its role in maintaining 3D genome structure mediated by TE binding. Overall, our findings demonstrate that TEs are crucial determinants of 3D genome organization in mammalian cells. Key findingsO_LITEs determine 48% of the 3D genome structure alone, and 70% of heterotypic contacts. C_LIO_LIA/B compartments, TADs, and loop signatures can be retrieved using TE-mapped reads only. C_LIO_LITFs can be divided into contact formers and breakers at TEs. C_LIO_LISMARCA4 and MAFK build chromatin contacts between TE sequences. C_LI

cell biology↗

bioRxiv2024

Decoding Olfactory Bulb Output: A Behavioral Assessment of Rate, Synchrony, and Respiratory Phase Coding

The olfactory system is a well-known model for studying the temporal encoding of sensory stimuli due to its rhythmic stimulus delivery through respiration. The sniff rhythm is considered critical to structuring the output of computation in the primary olfactory area, the olfactory bulb. Here, Neuropixels recording from awake, head-fixed mice confirmed that both the rate and sniff-locked spike timing are informative about odour identity. We tested the behavioural importance of these temporal features using simple closed-loop optogenetics embedded in custom behavioural paradigms. We found that mice perceive differences in evoked spike counts and discriminate between synchronous vs. asynchronous activations of the output neurons. Surprisingly, they failed to distinguish the timing of evoked activity relative to the sniff cycle. These results challenge the utility of internally generated rhythms as reference signals in the neural encoding of the environment.

neuroscience↗

bioRxiv2024

Aerobic capacity and exercise mediate protection against hepatic steatosis via enhanced bile acid metabolism.

High cardiorespiratory fitness and exercise show evidence of altering bile acid (BA) metabolism and are known to protect or treat diet-induced hepatic steatosis, respectively. Here, we tested the hypothesis that high intrinsic aerobic capacity and exercise both increase hepatic BA synthesis measured by the incorporation of 2H2O. We also leveraged mice with inducible liver-specific deletion of Cyp7a1 (LCyp7a1KO), which encodes the rate-limiting enzyme for BA synthesis, to test if exercise-induced BA synthesis is critical for exercise to reduce hepatic steatosis. The synthesis of hepatic BA, cholesterol, and de novo lipogenesis was measured in rats bred for either high (HCR) vs. low (LCR) aerobic capacity consuming acute and chronic high-fat diets. HCR rats had increased synthesis of cholesterol and certain BA species in the liver compared to LCR rats. We also found that chronic exercise with voluntary wheel running (VWR) (4 weeks) increased newly synthesized BAs of specific species in male C57BL/6J mice compared to sedentary mice. Loss of Cyp7a1 resulted in fewer new BAs and increased liver triglycerides compared to controls after a 10-week high-fat diet. Additionally, exercise via VWR for 4 weeks effectively reduced hepatic triglycerides in the high-fat diet-fed control male and female mice as expected; however, exercise in LCyp7a1KO mice did not lower liver triglycerides in either sex. These results show that aerobic capacity and exercise increase hepatic BA metabolism, which may be critical for combatting hepatic steatosis. HighlightsO_LIRats with intrinsic high aerobic capacity have more significant reductions in de novo lipogenesis and increased cholesterol and bile acid synthesis on a high-fat diet compared to rats with low aerobic capacity. C_LIO_LIChronic exercise increases hepatic bile acid synthesis in mice. C_LIO_LILoss of Cyp7a1 blunts the capacity for exercise to increase bile acid synthesis and treat hepatic steatosis in male and female mice fed a high-fat diet. C_LI

physiology↗

bioRxiv2024

Coma pattern-based autofocusing unlocks superior performance in unravelling single-cell dynamics during bacterial cold shock response

Imaging-based single-cell physiological profiling holds great potential for uncovering fundamental bacterial cold shock response (CSR) mechanisms, but its application is impeded by severe focus drift during rapid temperature downshifts required for CSR induction. Here, we introduce LUNA (Locking Under Nanoscale Accuracy), an innovative autofocusing method that leverages the coma pattern of detection light to characterize focus drift. LUNA improves the focusing precision down to 3 nm and extends the focusing range to at least 40 times the objective depth-of-focus. These advancements enable us to investigate the complete dynamics of bacterial single-cell CSR, revealing continuous cellular growth and division. We resolve a three-phase adaptation process characterized by distinct growth deceleration dynamics, and show that bacterial cells maintain robust size regulation and coordinate uniform adaptation to cold shock through synchronized growth and elapsed cycles. Notably, a model based on scattering theory reconciles the paradox between the growth lag of batch culture and continuous single-cell growth. These findings fundamentally transform our understanding of bacterial CSR and highlight LUNAs excellent potential for expanding state-of-the-art research in biology.

microbiology↗

bioRxiv2024

Strong segregation promotes self-destructive cooperation

Self-destructive cooperator (SDC), where individuals sacrifice themselves for others, poses significant personal costs yet is widespread in nature. Traditional group selection theory struggles to explain its persistence, as the extreme cost of self-destruction typically exceeds the benefit to these individuals. Here, we predict that this behavior can endure in structured environments with strong segregation, where populations are divided into homogenous groups originating from one or two founding members. In such contexts, the benefits derived from SDC are primarily confined within the homogenous SDC groups, thus preserving the value of this altruistic sacrifice and ensuring its maintenance. To validate our hypothesis, we employ a synthetic system with engineered bacteria to mimic both SDC and non-sacrificing cheaters. We then conduct automated experiments facilitated by biofoundry technology to monitor and operate the subgroups with diverse growth behaviors stemming from a restricted number of initial cells because of strong segregation. Eventually, we demonstrate that SDC indeed maintains under strong segregation, and high stress benefits SDC because it reduces the benefits received by cheaters in heterogenous subgroups. This study extends the group selection theory to encompass even the most extreme manifestations of altruism and highlights the potential of automation in evolutionary research.

microbiology↗