Biology subjects

Mishra, D.

Publications and source records attributed to Mishra, D..

At least 19 recordsLinked to original sources

bioRxiv2026

Rewiring systemic nodulation control to engineer heat-tolerant nitrogen fixation in Medicago truncatula and chickpea

Root nodule symbiosis allows legumes to meet their nitrogen requirements. However, the causes of symbiosis failure at high temperatures remain unknown. We demonstrated that elevated temperatures affect both the host and the microbial partner in Medicago truncatula and chickpea. Rhizobial viability and nod gene expression persisted under heat stress, but plant transcriptome analysis revealed a strong downregulation of the nodule organogenesis machinery. Nodule organogenesis was restored by constitutive overexpression of NIN-LBD16-NFYA1-NFYB16, miR2111, and CLE5 knockdown but failed to restore nitrogen fixation. In contrast, the genetic manipulation of the competence pathway involving CEP peptides significantly improved both nodulation and nitrogen fixation. Constitutive loss of the autoregulation of nodulation (AON) pathway in the SUNN alleles also rescued root nodulation and nitrogen fixation. Therefore, heat stress perturbs the balance between AON and the competence pathway, and genetic manipulation of these pathways is a promising approach to engineer thermotolerant nitrogen fixation in crop legumes.

plant biology↗

bioRxiv2026

Evidence of Filopodial translocation of Blastema associated microRNA rich Exosome like Extracellular Vesicles

Zebrafish (Danio rerio) possess remarkable regenerative capacity, making them an ideal model for studying the molecular mechanisms underlying tissue regeneration. In this article we report the identification of blastema linked exosome like extracellular vesicles (EVs) in zebrafish, that to the vesicles were plausibly being translocated in the proximo-distal axis through filipodia. We further thoroughly examined the exosome like EVs isolated from regenerating tissues of zebrafish caudal fins to characterize their nucleic acid cargo and evaluate their potential regulatory functions in regeneration. Caudal fins were amputated and allowed to regenerate and exosome like EVs isolated from blastema tissues displayed increased abundance compared to non-amputated controls. RNA sequencing identified a dynamic cluster of EV linked microRNAs (miRs). These differentially expressed miRs, including dre-miR-21, dre-miR-200b, dre-miR-218a and dre-let-7e were upregulated and associated with promoting proliferation, migration, differentiation, and tumour suppression pathways. Moreover, dre-miR-100, dre-miR-146a and dre-miR-200c regulated osteogenic differentiation, inflammatory signalling, epithelial-mesenchymal transition, and cell adhesion. Regeneration is generally believed to be coordinated only by local morphogen diffusion. Through this study it is indicative that filipodia bound EVs might have a pivotal role in long-range communication between blastema and the proximal tissues during the regeneration process. A detailed analyses of the miR targets and their validation could potentially lead to novel advancement and solutions in the field of regeneration and regenerative medicine in the near future.

Developmental Biology↗

bioRxiv2026

EML4-ALK Fusion Rewires Transcriptomic, miRNA, and CAF-Associated Programs in Non-Small Cell Lung Cancer

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=186 SRC="FIGDIR/small/717853v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@a696f3org.highwire.dtl.DTLVardef@1005c11org.highwire.dtl.DTLVardef@9c65bborg.highwire.dtl.DTLVardef@1dafb2d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG This study establishes an integrative framework that combines paired mRNA/miRNA profiling with immune microenvironmental features to clarify how EML4-ALK fusions shape transcriptomic and post-transcriptional networks in Non-small cell lung cancer (NSCLC). Using paired mRNA-seq and miRNA-seq data generated from the same patients, we compared fusion-positive and fusion-negative NSCLC across three interconnected layers: (i) transcriptome architecture, including differential expression, pathway, and network analyses; (ii) the miRNA-mRNA regulatory axis, encompassing dysregulated miRNAs, target repression and sponging, and fusion-specific regulatory pairs; and (iii) the tumor microenvironment, with emphasis on immune and stromal infiltration, particularly cancer-associated fibroblast (CAF)-linked extracellular matrix (ECM) and adhesion programs. Our analyses revealed a distinct reprogramming pattern in fusion-positive NSCLC, marked by activation of metabolic and proteostasis pathways, including N-glycan metabolism coupled to ER export, together with attenuation of immune-stromal communication, adhesion, ECM, calcium signaling, and PI3K/VEGF-axis transcription relative to fusion-negative NSCLC. We also identified fusion-associated microRNA perturbations, including an exclusively upregulated miR-3065-centered regulatory hub predicted to repress ECM- and adhesion-related genes (PDGFRB, CTSK, COL4A2, SPARC, FBN1, and LUM) in fusion-positive tumors, in contrast to broader miRNA network rewiring in fusion-negative tumors targeting ciliary and mitotic hubs. Tumor microenvironment analysis further distinguished the subtypes, with fusion-positive tumors showing reduced CAF infiltration relative to fusion-negative tumors and concordant gene-CAF associations. By linking mechanistic insight with candidate biomarkers and targetable pathway nodes, this work provides a basis for precision strategies in both fusion-positive and fusion-negative cohorts and broadens the therapeutic perspective beyond kinase inhibition alone.

systems biology↗

bioRxiv2026

Fusion-driven post-transcriptional network orchestrates ferroptosis resistance, dormancy, and immune remodeling in PRCC-TFE3 renal cell carcinoma

TFE3-rearranged papillary renal cell carcinoma (pRCC) remains poorly understood due to its rarity and complex biology. By integrating matched mRNA and miRNA sequencing from the TCGA-KIRP cohort, this study reveals a fusion-specific post-transcriptional program orchestrating ferroptosis resistance, metabolic adaptation, adhesion loss, immune remodeling, and dormancy-associated signaling. Fusion-positive tumors exhibited coordinated upregulation of antioxidant and mTORC1 components (SOD2, GPX4, G6PD, NQO1, FNIP2, RRAGC), reinforced by loss of miRNA-mediated repression. In parallel, elevated miRNAs (miR-185, miR-148a, miR-130b, miR-342) suppressed MAPK, Wnt, and tight-junction genes, generating a low-proliferative, adhesion-deficient state. AGO2-compatible miRNA-mRNA structural modeling validated key duplexes, linking miRNA regulatory specificity to fusion-driven transcriptional outputs. Immune profiling revealed reduced CD3 T cells but enrichment of CD8 and NK cells, supporting a remodeled yet persistence-permissive microenvironment. Finally, connectivity mapping analysis identified candidate leads targeting the MAPK-Wnt axis. These findings define a multilayered RNA regulatory architecture unique to PRCC-TFE3 tumors.

systems biology↗

bioRxiv2025

Screen-VarCal: An Interpretable Probabilistic Framework for Recalibrating ACMG Rule-Based Variant Classification in Preventive Medicine

Motivationhole-genome sequencing (WGS) is increasingly used for preventive genomics, yet rule-based ACMG engines such as InterVar were tuned for high pre-test probability diagnostics. In screening contexts, these heuristics can inflate pathogenic/likely pathogenic (P/LP) calls, prompting unnecessary follow-up. We sought an interpretable, data-driven recalibration tailored to proactive use. ResultsAcross 20 WGS cases, InterVar flagged 109 variants as P/LP; only 18 (16.5%) were concordant with ClinVar P/LP assertions. The remaining 83.5% were largely absent from Clin-Var (n=68) or mapped to benign/likely benign (n=13). Nearly all flagged variants (96%) were heterozygous, predominantly in autosomal recessive genes (e.g., FAM20C, MTMR2 ), indicating a dominant carrier inflation effect; recurrent loci (e.g., ATXN3, FAM20C ) further amplified yield. We introduce Screen-VarCal, an interpretable probabilistic framework that combines logistic regression with isotonic adjustment to align InterVar outputs with observed ClinVar P/LP distributions. Screen-VarCal reduced false positives by[~] 60% while retaining all ClinVar-concordant findings and yields calibrated probabilities with coefficients that transparently link ACMG evidence categories (PVS/PS/PM/PP/BS/BP) and zygosity to risk.

bioinformatics↗

bioRxiv2025

Genomic diversity analysis enables development of pan-Dengue Toehold RNA sensors

The Dengue virus (DENV) like many other RNA viruses exhibits high genome sequence diversity. This poses a challenge to nucleic acid-based diagnostics, rendering them inefficient at detecting the diverse DENV strains circulating in a population. In this study, we address this challenge by developing a Toehold sensor assay that despite significant genomic diversity is able to detect [~]99.4% of all strains of DENV. To this end, our workflow first identifies relatively conserved short stretches (36-nt) within all DENV genomes, which could potentially serve as triggers that activate Toehold RNA sensors. We then add a crucial step of mismatch-tolerance that allows related triggers with high sequence diversity and multiple mismatches in the sensor-binding region to be efficiently sensed by the same sensor. The sensitivity of the Toehold sensor assay is often increased by inclusion of an isothermal RNA amplification step. We show by employing multiple primer sets that diverse trigger RNAs from all four serotypes of the dengue virus can be successfully amplified and subsequently detected by the same sensor. Together, this approach has resulted in a pan-dengue Toehold sensor assay, which presents a powerful nucleic acid detection platform to detect viruses with high sequence diversity.

molecular biology↗

bioRxiv2025

Integrative Transcriptomic and miRNA Analysis Reveals Immune Suppression and Metabolic Reprogramming in FGFR3-TACC3 Fusion-Positive versus Fusion-Negative Bladder Cancer

FGFR3-TACC3 gene fusion drives a molecularly distinct subset of bladder cancer characterized by post-transcriptional immune evasion and metabolic rewiring. To elucidate the transcriptomic and regulatory consequences of this fusion, we performed an integrative analysis of mRNA and miRNA expression profiles in fusion-positive versus fusion-negative bladder tumors using TCGA-derived RNA-Seq and miRNA-Seq data. Fusion-positive tumors exhibited upregulation of mitochondrial oxidative phosphorylation and ribosomal genes (e.g., COX5B, ATP5F1D, RPS15) and marked downregulation of immune regulatory genes (e.g., CD4, STAT3, IL6, CD86, PTPRC). Pathway enrichment revealed suppression of JAK/STAT, PD-L1 signaling, and cytokine networks, consistent with a fusion-driven immunosuppressive phenotype. We identified fusion-specific miRNA-mRNA regulatory interactions, including upregulated miRNAs (miR-1226-3p, miR-149-5p, miR-301b-3p) that target immune transcripts and downregulated miRNAs (miR-199b-5p, miR-214-3p) that normally suppress mitochondrial and ribosomal genes. In contrast, fusion-negative tumors displayed an immunoreactive signature marked by elevated IFNG, CXCL10, and IRF1 expression and downregulation of immune-suppressive miRNAs (miR-125a-5p, miR-23b-3p). Minimum free energy analysis and AlphaFold3-based AGO2-RISC docking confirmed structural feasibility of 3D duplex formation for 13 miRNA-target pairs, supporting active silencing complexes. Immune deconvolution revealed reduced infiltration of cytotoxic T cells, NK cells, and dendritic cells in fusion-positive tumors, while fusion-negative tumors showed robust immune cell presence. Key gene-immune cell correlations further confirmed differential immune architecture: SRC and CD4 were strongly linked to suppressed infiltration in fusion-positive tumors, while IFNG and CXCL10 positively correlated with T and NK cell abundance in fusion-negative cases. ROC analysis highlighted COMT, RPS15, and miR-187-3p as robust classifiers of fusion-positive tumors (AUC > 0.9), and CXCL10, CD74, and miR-142 for fusion-negative tumors. Connectivity Map analysis highlighted Lofexidine and Lenalidomide as candidate compounds predicted to reverse fusion-specific transcriptional programs. Collectively, our findings define immune suppression and metabolic reprogramming as core features of FGFR3-TACC3 fusion-positive bladder cancer and nominate fusion-specific miRNA-mRNA interactions as candidate biomarkers and therapeutic targets.

cancer biology↗

bioRxiv2025

BMI-1 Modulation and Trafficking During M Phase in Diffuse Intrinsic Pontine Glioma

BMI-1 (B cell-specific Moloney murine leukemia virus integration site 1) has been implicated in both normal and cancer cell biology. While the canonical function of BMI-1 involves epigenetic repression, novel extra-nuclear functions have been recently reported. In the present study, we demonstrate that the phosphorylation of BMI-1 in diffuse intrinsic pontine glioma (DIPG) cells occurs in M phase and that triggers simultaneous translocation of the phosphorylated BMI-1 to the cytoplasm. This translocation is mediated by the RanGTP-dependent transporter CRM1, also known as exportin. Furthermore, we uncovered a previously unidentified nuclear export signal (NES) in BMI-1 protein, suggesting an active transport type of modified BMI-1 mediated by CRM1. These findings associate BMI-1 phosphorylation with its trafficking in M phase. Collectively, this study sheds light on the molecular mechanisms underlying BMI-1 functions in DIPG, thereby potentially paving the way for the development of targeted therapeutic strategies related to M phase progression.

cancer biology↗

bioRxiv2025

Spatial differentiation of proteome in cervical cancer tissues using Imaging Mass Spectrometry

Cervical cancer, which is the fourth most common gynaecological cancer across the globe, has a poorly understood molecular pathogenesis and etiology. Current methods of diagnosis are based on cytology, histology and presence of Human Papillomavirus (HPV). Shortcomings of these methods lie with poor quality of smears which is very common in Papanicolaou (pap) smears, limited sensitivity in terms of early detection, dependence on presence of HPV, etc. Due to its high sensitivity and non-targeted approach, Matrix Assisted Laser Desorption Ionization based Imaging Mass Spectrometry (MALDI-IMS) might be advantageous to understand the pathogenesis, molecular mechanism, precise identification of surgical margins and identification of novel biomarkers. Since it can also identify proteins in the extracellular matrix, it is especially beneficial for the tissue types with sparse cells and excessive extracellular matrix. Although tissue proteome profiling for cervical cancer were reported, the heterogeneous distribution of proteins across cervical cancer tissues havent been explored. In this study, we employed a non-targeted MALDI-IMS based approach to profile the spatial distribution of proteins within cervical cancer tissues. We observed overexpression of Keratin 5 and Prelamin A/C in the region of cervical cancer tissues which were categorically labelled with cancerous morphology using histopathological examination. Both these proteins have been earlier associated with progression and aggressiveness of other cancers like breast and prostate cancers. However, no such reports are available for cervical cancer. Further studies are required on a large dataset to validate and quantitate these proteins as biomarkers for early diagnosis and prognosis of cervical cancer.

cancer biology↗

bioRxiv2025

NF-κB mediates transactivation of HNRNPD, resulting in PTEN destabilization and constitutive activation of the PI3K-AKT pathway in oral cancer cells

Heterogeneous Ribonucleoprotein D (hnRNPD), an RNA binding protein transcriptionally upregulated by NF-{kappa}B transcription factor, is associated with poor outcome of Oral Squamous Cell Carcinoma (OSCC). However, the role of hnRNPD in OSCC remains elusive. This study reveals that hnRNPD positively affects the proliferation, migration, invasion, and survival of OSCC cells. Transcriptome profiling in hnRNPD knockout cells identified significant upregulation of PTEN and inhibition of the PI3K/AKT/mTOR axis. HnRNPD mediates the destabilization of PTEN mRNA by binding to the class II AU-Rich Element (ARE) in 3UTR of PTEN. The expression of hnRNPD and PTEN are strongly negatively correlated in OSCC tissue specimens, further corroborating hnRNPD-mediated PTEN destabilization. The hnRNPD knockout inhibited autophagy, evident by an accumulation of autophagic vesicles and decreased autophagic flux. Mechanistically, the hnRNPD knockout reduced the expression of NF-{kappa}B, eventually downregulating its transcriptional target LC3b, a key mediator of autophagy. SA-{beta}-Galactosidase staining in hnRNPD KO cells conclusively demonstrated the onset of cellular senescence. The present study demonstrates hnRNPD-driven positive modulation of autophagy via NF-{kappa}B, independent of the PI3K/AKT/mTOR axis, highlighting it as a novel therapeutic target for treating oral cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/631360v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@11f6844org.highwire.dtl.DTLVardef@f65124org.highwire.dtl.DTLVardef@1492571org.highwire.dtl.DTLVardef@13931dd_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIHnRNPD mediates oral cancer cell proliferation, migration, invasion, and survival. C_LIO_LIHnRNPD acts as a novel regulator of the PI3K/AKT/mTOR axis by destabilization of PTEN. C_LIO_LINF-{kappa}B/RelA downregulated on knockout of HNRNPD, inhibiting autophagy through downregulating its transcriptional target LCB-II. C_LIO_LIHnRNPD mediates cellular senescence in oral cancer cells. C_LI

cancer biology↗

bioRxiv2024

PANOMIQ: A Unified Approach to Whole-Genome, Exome, and Microbiome Data Analysis

The integration of whole-genome sequencing (WGS), whole-exome sequencing (WES), and microbiome analysis has become essential for advancing our understanding of complex biological systems. However, the fragmented nature of current analytical tools often complicates the process, leading to inefficiencies and potential data loss. To address this challenge, we present PANOMIQ, a comprehensive software solution that unifies the analysis of WGS, WES, and microbiome data into a single, streamlined pipeline. PANOMIQ is designed to facilitate the entire analysis process from raw data to interpretable results. It is the fastest algorithm that can achieve results much more quickly compared to traditional pipeline approaches of WGS and WES analysis. It incorporates advanced algorithms for high-accuracy variant calling in both WGS and WES, along with robust tools for characterizing microbial communities. The softwares modular architecture allows for seamless integration of these diverse data types, enabling researchers to uncover complex interactions between host genomics and microbiomes. In this study, we demonstrate the capabilities of PANOMIQ by applying it to a series of datasets encompassing a wide range of applications, including disease association studies and environmental microbiome profiling. Our results highlight PANOMIQs ability to deliver comprehensive insights, significantly reducing the time and computational resources required for multi-omic analysis. By providing a unified platform for WGS, WES, and microbiome analysis, PANOMIQ offers a powerful tool for researchers aiming to explore the full spectrum of genomic and microbial diversity. This software not only simplifies the analytical workflow but also enhances the depth of biological interpretation, paving the way for more integrated and holistic studies in genomics and microbiology.

bioinformatics↗

bioRxiv2024

Clonal spheroids capture functional and genetic heterogeneity of head and neck cancer

Head and neck cancer squamous cell carcinoma (HNSCC) cells exhibit both structural and functional diversity, making them valuable models for understanding tumor heterogeneity at clinical levels. In this study, we generated single-cell-derived spheroids (SCDS) from HNSCC cell lines and patient tumor cells using scaffold- and non-scaffold-based methods to assess this variability. A distinct structural variability among these SCDS, categorized as hypo- and hyperproliferative spheroids based on size, was observed. Hyperproliferative spheroids demonstrated heightened proliferative and tumorigenic potential and increased sensitivity to cisplatin and radiation, while hypoproliferative spheroids exhibited enhanced migratory capabilities. Single-cell RNA sequencing (scRNA-seq) of hypo- and hyperproliferative spheroids provided insights into the transcriptional landscape of HNSCC cells, validating the observed structural and functional heterogeneities within primary tumors. These functionally and genetically characterized spheroids offer valuable tools for the development of next-generation therapeutics. Statement of SignificanceEstablishment and characterization of single-cell-derived spheroids from head and neck cancer cells, employing scaffold and non-scaffold materials, demonstrate functional and genetic heterogeneity. Single-cell analysis reveals correlations between genetic diversity and spheroid functionality. These characterized spheroids offer potential for advancing therapeutics development.

cancer biology↗

bioRxiv2024

Mutational analysis of the F plasmid partitioning protein ParA reveals novel residues required for oligomerisation and plasmid maintenance

Mobile genetic elements such as plasmids play a crucial role in the emergence of antimicrobial resistance. Hence, plasmid maintenance proteins like ParA of the Walker A type cytoskeletal ATPases/ ParA superfamily are potential targets for novel antibiotics. Plasmid partitioning by ParA relies upon ATP-dependent dimerisation and formation of chemophoretic gradients of ParA-ATP on bacterial nucleoids. Though polymerisation of ParA has been reported in many instances, the need for polymerisation in plasmid maintenance remains unclear. In this study, we provide novel insights into the polymerisation of ParA and the effect of polymerisation on plasmid maintenance. We first characterise two mutations, Q351H and W362E, in ParA from F plasmid (ParAF) that form cytoplasmic filaments independent of the ParBSF partitioning complex. Both mutants fail to partition plasmids, do not bind non-specific DNA and act as super-repressors to suppress transcription from the ParA promoter. Further, we show that the polymerisation of ParAF requires the conformational switch to the ParA-ATP* state. We identify two mutations, R320A in the C-terminal helix-14 and E375A helix-16 of ParAF, that abolish filament assembly and affect plasmid partitioning. Our results thus suggest a role for higher-order structures or polymerisation of ParA in plasmid maintenance.

microbiology↗

bioRxiv2024

Conformational switch of a peptide provides a novel strategy to design peptide loaded porous organic polymer for Pyroptosis pathway mediated cancer therapy

While peptide-based drug development is now extensively explored, this strategy does have limitations, which come from their rapid excretion from the body (or shorter half-life in the body), and vulnerability to protease-mediated degradation. To overcome these limitations, here we introduce a novel strategy for the development of a peptide-based anticancer agent using the conformation switch property of a chameleon sequence stretch, which we derived from a mycobacterium secretory protein, MPT63. Then, we loaded this peptide in a new porous organic polymer (PG-DFC-POP) synthesized using phloroglucinol and acresolderivative via condensation reaction for delivering the peptide selectively to the cancer cells. Employing an ensemble and single molecule approaches, we demonstrate that this peptide undergoes a disordered to alpha-helical conformational transition, which is triggered by a low pH environment inside cancer cells. This adopted alpha-helical conformation results in the formation of proteolysis-resistant oligomers, which show efficient membrane pore-forming activity selectively for negatively charged phospholipid which is accumulated in cancer cell membrane. Our in vitro and in vivo experimental results demonstrate that the peptide-loaded nanomaterial PG-DFC-POP-PEP 1 exhibits significant cytotoxicity in cancer cells, leading to cell death through the Pyroptosis pathway that is confirmed by monitoring numerous associated events starting from lysosome membrane damage to GSDMD-induced cell membrane demolition. We believe that this novel conformational switch-based drug design strategy has great potential in endogenous environment-responsive cancer therapy and the development of future drug candidates to mitigate cancers.

biochemistry↗

bioRxiv2023

Listeria adhesion protein orchestrates caveolae-mediated apical junctional remodeling of epithelial barrier for L. monocytogenes translocation

The cellular junctional architecture remodeling by LAP-Hsp60 interaction for L. monocytogenes (Lm) passage through the epithelial barrier is incompletely understood. Here, using the gerbil model, permissive to internalin (Inl) A/B-mediated pathways like in humans, we demonstrate that Lm crosses the intestinal villi at 48 h post-infection. In contrast, the single isogenic (lap[boxh] or {Delta}inlA) or double (lap[boxh]{Delta}inlA) mutant strains show significant defects. LAP promotes Lm translocation via endocytosis of cell-cell junctional complex in enterocytes that do not display luminal E-cadherin. In comparison, InlA-mediated transcytosis occurs in enterocytes displaying apical E-cadherin during cell extrusion and mucus expulsion from goblet cells. LAP hijacks caveolar endocytosis to traffic integral junctional proteins to the early and recycling endosomes. Pharmacological inhibition in a cell line and genetic knock-out of caveolin-1 in mice prevents LAP-induced intestinal permeability, junctional endocytosis, and Lm translocation. Furthermore, LAP-Hsp60-dependent tight junction remodeling is also necessary for InlA access to E-cadherin for Lm intestinal barrier crossing in InlA-permissive hosts.

microbiology↗

bioRxiv2023

Natural genomic variation in rice blast genomes is associated with specific heterochromatinmodifications

Genome organization in eukaryotes exhibits non-random patterns tied to transcription, replication, and chromatin. However, the driving forces across these processes, and their impacts on genome evolution remain unclear. To address this, we analyzed sequence data from 86 Magnaporthe oryzae isolates, a globally important plant pathogenic fungus, alongside new reference genomes, to investigate DNA sequence variation and the epigenome. Histone modification profiles were obtained through genome-wide chromatin immunoprecipitation-sequencing of the four new reference strains, which revealed that repressive histone marks (H3K27me3, H3K9me3) were associated with SNP and INDEL frequency. Densely grouped SNPs were found to reside in heterochromatin, often outside transposable elements, highlighting the link between heterochromatin and DNA variation. Even when controlling for selection, silent SNP frequency/kb was higher in H3K27me3-associated genes. Effector genes, key to pathogenicity, also displayed this trend. Comparing the reference strains, euchromatic regions were often syntenic, while heterochromatic regions trended towards non-syntenic. Heterochromatin emerged as a major factor associated with diverse DNA variations in M. oryzae populations, even when accounting for selective pressure. This underscores heterochromatins pivotal role in shaping genetic diversity in these mainly asexually reproducing fungi.

evolutionary biology↗

bioRxiv2023

Extended lifespan in female Drosophila melanogaster through late-life caloric restriction.

Calorie restriction has many beneficial effects on healthspan and lifespan in a variety of species. However, how late in life application of caloric restriction can extend fly life is not clear. Here we show that late-life calorie restriction increases lifespan in female Drosophila melanogaster aged on a high calorie diet. This shift results in rapid decrease in mortality rate and extends fly lifespan. In contrast, shifting female flies from a low to a high calorie diet leads to a rapid increase in mortality and shorter lifespan. These changes are mediated by immediate metabolic and physiological adaptations. One of such adaptation is rapid adjustment in egg production, with flies directing excess energy towards egg production when shifted to a high diet, or away from reproduction in females shifted to low caloric diet. However, lifelong female fecundity reveals no associated fitness cost due to CR when flies are shifted to a high calorie diet. In view of high conservation of the beneficial effects of CR on physiology and lifespan in a wide variety of organisms, including humans, our findings could provide valuable insight into CR applications that could provide health benefits later in life.

physiology↗

bioRxiv2023

Late- life shift in caloric intake affects fly longevity and metabolism

Caloric restriction (CR) delays the onset of age-related changes and extends lifespan in most species, but how late in life organisms benefit from switching to a low-calorie (L) diet is unexplored. We transferred wild type male flies from a high- (H) to a L-calorie diet (HL) or vice versa (LH) at different times. Late-life HL shift immediately and profoundly reduces fly mortality rate to briefly lower rate than in flies on a constant L diet, and increases lifespan. Conversely, a LH shift increases mortality and hazard rate, which is temporarily higher than in flies aged on a H diet, and leads to shorter lifespan. Transcriptomic changes within 48 hours following diet shift uncover physiological adaptations to available nutrients. Unexpectedly, more abundant transcriptomic changes accompanied LH shift, including ribosome biogenesis, and promotion of growth, which likely contributes to higher mortality rate. Considering that the beneficial effects of CR on physiology and lifespan are conserved across many organisms, our findings suggest that CR interventions in older humans may counteract the detrimental effects of H diets even when initiated later in life.

physiology↗