Biology subjects

Torres, J.

Publications and source records attributed to Torres, J..

At least 19 recordsLinked to original sources

bioRxiv2026

Evolution of endogenized densoviral elements across aphid species

AO_SCPLOWBSTRACTC_SCPLOWEndogenous viral elements (EVEs) are widespread across animal genomes, yet the processes governing EVE evolution and diversification remain poorly understood. Here, we characterize the evolution of densoviral EVEs and exogenous densoviruses across the aphid tribe Macrosiphini, an agriculturally important group in which exogenous densoviruses and their endogenous derivatives have been linked to the plastic production of wings. Using new genome assemblies, transcriptomics, and phylogenetic analysis, we find that EVE content varies extensively across species. Moreover, we discovered a novel densovirus that is vertically transmitted, but phylogenetic incongruence between other densoviruses and their hosts suggests that horizontal transmission may also occur. Finally, we show that EVE-mediated regulation of wing plasticity extends across species that use different environmental signals to induce winged offspring. Our study shows that in this system, the evolution of EVEs is highly variable and lineage-specific, generating genomic patterns that cannot be predicted from host evolutionary relationships.

evolutionary biology↗

bioRxiv2026

Open neuroinformatics infrastructure ecosystem for federated multisite studies

Despite growing understanding of the benefits of having Findable, Accessible, Interoperable, and Reusable (FAIR) data, many datasets still cannot be shared. Federated analysis methods can enable multisite studies that do not require the sharing of participant-level information. However, there are many practical hurdles that prevent the large-scale adoption of federated methods. We discuss challenges related to cross-site data preparation for federated learning, present solutions offered by recent neuroinformatics projects, and showcase an example of tool integration applied to neurodegenerative disease data.

neuroscience↗

bioRxiv2026

Patient iPSC-Derived Cartilage Organoids Reveal Defective ECM Deposition and Altered Chondrogenic Trajectory in Saul-Wilson Syndrome

Saul-Wilson syndrome (SWS) is a skeletal dysplasia characterized by primordial dwarfism and progeroid features caused by a recurrent dominant COG4 variant (p.G516R). We previously showed that this mutation accelerates Golgi retrograde trafficking and disrupts glycosylation of the proteoglycan decorin, while zebrafish models revealed defects in chondrocyte elongation and intercalation. We have also shown that the SW1353 chondrosarcoma cells carrying the SWS variant exhibit reduced secretion of extracellular matrix (ECM) components. While these results indicate a critical function of COG4 in Golgi processing, the developmental process leading to skeletal dysplasia in SWS patients remains unknown. Here, we generated patient-derived iPSC cartilage organoids (SWS organoids), modeling early human chondrogenesis. SWS organoids failed to produce cartilage structures and displayed poor expression of chondrogenic markers. Time-course RNA-seq analysis of the chondrogenic process revealed reduced activation of gene networks involved in skeletal development, ECM organization, ossification, and glycosaminoglycan metabolism. Spatial multiomic analysis of protein and glycosylation by CODEX and GLYPH imaging revealed an altered chondrogenic trajectory, persistence of mesenchymal states, global glycosylation changes, and reduced deposition of chondroitin sulfate proteoglycans. These results indicate that the COG4 mutation disrupts ECM glycosylation and chondrogenic commitment, and that SWS organoids model early defects in cartilage formation underlies impaired skeletal growth in SWS. HighlightsO_LIPatient iPSC-derived cartilage organoids model development defects in Saul-Wilson syndrome C_LIO_LISWS organoids show defective extracellular matrix deposition and attenuated chondrogenic gene expression C_LIO_LIGlycan profiling reveals global glycosylation defects and deficient proteoglycan GAG chains C_LIO_LIAn early developmental impairment in chondrogenesis alters skeletal formation in Saul-Wilson syndrome C_LI

developmental biology↗

bioRxiv2026

Modulation of liposome membranes by the C-terminal domain of the coronavirus envelope protein

The coronavirus envelope (E) protein is a viroporin that plays a key role in viral assembly, release, budding and pathogenesis. E protein forms oligomeric ion channels that can activate immune responses. However, high-resolution structural data for its extramembrane domains is limited. The C-terminal domain of SARS-CoV has been shown previously to form amyloid fibers, and here we show that these fibers can modulate the shape of liposomes. The propensity to form fibrils, and their effect on liposomes, was examined for sequences belonging to the four clades of coronaviruses. Electron microscopy data shows that the C-terminal domain in E protein adopts a filamentous structure. These findings demonstrate the potential of these peptides to modulate membranes, providing a possible mechanism by which E protein interacts with membranes in the host cell.

biophysics↗

bioRxiv2025

Orangutan: an R package for analyzing and visualizing phenotypic data in the context of ecology and systematics

AimPhenotypic characters have long been central to species diagnosis and delimitation and remain indispensable even in the age of genomics. However, phenotypic datasets are often complex-- spanning dozens of traits of varying types and units, with correlated variables and unbalanced sampling--posing challenges for robust, reproducible analysis. Existing software solutions are fragmented, usually requiring labor-intensive workflows across multiple tools and manual steps, which undermines reproducibility and hinders comparisons across studies. To address these methodological and practical challenges, I introduce Orangutan, an R package designed to provide a flexible, easy-to-implement framework for comparing groups using mensural and meristic data. InnovationOrangutan provides a flexible and efficient framework for analyzing mensural and meristic data, supporting a full suite of statistical and visualization tools optimized for species delimitation and population comparisons. The package streamlines the identification of diagnostic, non-overlapping traits between species, while enabling rigorous assessment of both individual and multivariate trait differences. Core features include optional allometric correction to remove size effects, automated selection of appropriate univariate tests with post hoc comparisons, and integrated multivariate analyses. All outputs, including summary statistics and annotated publication-ready figures, are generated with minimal coding, ensuring accessibility and standardization. Main ConclusionsEmpirical validation with real-world datasets--including animal and plant species-- demonstrates that Orangutan robustly identifies diagnostic traits, reveals both subtle and clear group differences, and achieves high classification accuracy with phenotypic data alone. By automating and unifying key analytical steps, Orangutan promotes reproducibility, transparency, and efficiency in phenotypic research. This package empowers researchers in taxonomy, ecology, and evolutionary biology to adopt quantitative best practices for species delimitation, facilitating comparative studies and advancing methodological standards in morphological data analysis. Orangutan is freely available with comprehensive documentation to support widespread adoption.

ecology↗

bioRxiv2025

Evaluation of antibiotic and peptide vaccine strategies for mirror bacterial infections

Recent advances in synthetic biology have raised concerns that the creation of bacteria composed completely of mirror-image biomolecules may be possible in the coming decades. Such "mirror bacteria" could pose an unprecedented biosecurity risk, as they are predicted to be highly virulent pathogens resulting from severe immune evasion. Pharmaceutical interventions, including antibiotics and vaccines, could likely provide some limited protection in the event of a mirror bacterial outbreak. Understanding the feasibility of specific pharmaceutical antimirror strategies may help inform the appropriate measures to confront the risks of mirror bacteria. Here, we experimentally evaluated the prospects of previously proposed antimirror antibiotic and vaccine strategies. First, we assessed the expected efficacy of existing antibiotics chloramphenicol, linezolid, tedizolid, and aztreonam against mirror bacteria by characterizing the antibacterial activities of their enantiomers against natural-chirality bacteria. We found that ent-chloramphenicol, ent-linezolid, ent-tedizolid, and ent-aztreonam exhibited minimal antibiotic activity, suggesting that their parent antibiotics would be ineffective against mirror bacterial infections. Second, to explore whether the enantiomers of existing antibiotics could be suitable as antimirror antibiotics, we evaluated the acute toxicities of ent-chloramphenicol, ent-linezolid, ent-tedizolid, and ent-aztreonam in mice, finding that these compounds have favorable acute toxicity profiles compatible with their continued development. Finally, we investigated D-peptide-based approaches to antimirror vaccines, finding that three bacterially-derived D-peptides induced robust D-peptide-specific antibody responses in mice when conjugated to a carrier protein and adjuvanted. Our results support previous suggestions that the enantiomers of existing antibiotics and D-peptide conjugate vaccines represent feasible pharmaceutical strategies against mirror bacterial infections. IMPORTANCETechnologies enabling the creation of mirror bacteria--bacteria constructed of molecules that are mirror images of those found in nature--may be on the horizon. If created, mirror bacteria would likely pose an unprecedented risk to life on earth given their evasion of natural immune responses. Although they would not protect against widespread environmental damage, antibiotics and vaccines could provide some limited protection to human populations in the event of a mirror bacterial outbreak. We experimentally assessed the prospects of three antimirror strategies: repurposing existing antibiotics, developing mirror versions of existing antibiotics, and developing vaccines based on mirror-image peptides. We broadly conclude that many existing antibiotics are unlikely to be effective against mirror bacteria, while the mirror images of existing antibiotics and mirror-image peptides could serve as foundations for antimirror antibiotics and vaccines, respectively. Our findings may help inform discussions on the proper role of medical countermeasures to defend against mirror bacteria.

microbiology↗

bioRxiv2025

Functional Group Composition: The Blueprint for Protein Interactions

Understanding the complex landscape of protein interactions, especially those involving intrinsically disordered proteins (IDPs), is fundamental yet challenging due to their structural heterogeneity and flexibility. Traditional sequence-based homology methods frequently fall short in characterizing IDP functions and interactions. Here, we present a novel approach leveraging supervised and unsupervised machine learning techniques, focusing exclusively on the compositional features of proteins. An Edmond-Ogston-inspired mixing model can reliably predict the degree of survivin (BIRC5) binding as a function of peptide composition alone, revealing a first interesting connection with the composition diagrams of chemical thermodynamics. By representing protein sequences through their functional group compositions, we demonstrate that specific compositions robustly predict binding interactions with survivin, an important human protein in cellular regulation pathways. Experimental validation via peptide microarray confirms the predictive power of our simplified compositional model, independent of exact amino acid sequences. Extending this method across the human proteome, we identified distinct compositional signatures correlating with survivin interactions and revealed fine grained biologically meaningful functional clusters based on compositional similarity. Our findings suggest a compositional blueprint underpinning protein interactions, offering a powerful, simplified framework to decode complex biological networks.

systems biology↗

bioRxiv2025

On the possible inhibition of macrophage inflammatory responses by phytic acid produced by Echinococcus multilocularis

Echinococcus multilocularis, causing agent of alveolar echinococcosis, down-regulates host immunity 1,2. Salzmann et al showed that macrophages close to the parasite produce little IL-6 and the parasite extract mimics this inhibition in cultured macrophages 3. The authors then showed that E. multilocularis contains phytic acid and that commercial phytic acid inhibits cytokine responses in stimulated macrophages. Through comparison with effects of EDTA and intracellular calcium measurements, they concluded that phytic acid inhibits macrophage responses through calcium depletion, extrapolating this conclusion to assays with parasite extract and infection setting. However, the interaction between phytic acid and calcium is complex 4,5. Calcium is indeed depleted in the assays with commercial phytic acid according to our quantitative predictions. However additional changes occur including formation of solid calcium phytate, which probably moderates the inhibition of responses observed under calcium depletion. We calculate that in the experiments with parasite extract, phytic acid present cannot deplete calcium and therefore inhibition must be driven by a different mechanism, possibly independent of phytic acid. Further, we argue that calcium depletion is an unlikely in vivo immune regulatory mechanism. We propose that biological assays using calcium phytate are needed for ascertaining whether phytic acid has biologically relevant anti-inflammatory activity.

immunology↗

bioRxiv2025

Expanding the fly eye gene regulatory network: from Drosophila to the hoverfly Episyrphus balteatus.

Comparing developmental mechanisms across long evolutionary distances is challenging, especially when the level of description in the compared species is very disparate. This is the case for the gene regulatory network (GRN) that underlies the development of compound eyes in insects, where the very detailed level description of the network in the fruit fly Drosophila melanogaster contrasts with the knowledge of the network in other well studied insects, such as the flour beetle Tribolium or the desert locust Schistocerca. It is not even known to what extent the Drosophila eye GRN is typical of flies (diptera). Here we have introduced the marmalade fly Episyrphus balteatus (Syrphidae), separated from Drosophila approximately 90 MYrs, as a fly species to compare the mechanisms of compound eye development. The Episyrphus eye develops from an imaginal disc which is, in the overall, similar to that of Drosophila. By generating parallel data sets in Episyrphus and Drosophila to maximize comparability, our results show how the genes known to participate in the early specification of the Drosophila eye and the onset of its differentiation are likely participating in the eye GRN of Episyrphus, further expanding the set of conserved genes/nodes in this network. This gene set might be the basis for further explorations of the developmental mechanisms involved in compound eye development beyond flies. By combining RNAseq and ATACseq profiling with TF motifs we derive the first eye GRN in Episyrphus. When built using Episyrphus/Drosophila conserved nodes, the resulting GRN model exhibited abundant internal connectivity, suggesting that, as proposed in Drosophila, the GRN is knitted with many regulatory feedbacks. Using link conservation as a criterion for discovering new regulatory interactions, we find that the AML1/Runx transcription factor lozenge (lz) is a negative regulator of the retinal determination gene dachshund (dac) in Drosophila. However, although many of the predicted regulatory links are conserved, a large number of regulatory connections seem species-specific, even among conserved nodes. This suggests quite a significant regulatory rewiring during the 90Myr period separating Episyrphus and Drosophila.

developmental biology↗

bioRxiv2025

Determination of Copy Number Variations and Affected Gene Networks in Breast Cancer from Mexican Patients

Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and high molecular heterogeneity. In this study, we performed a genome-wide analysis of copy number variations (CNVs) using high-density microarrays in tumor tissue (TUM), tumor adjacent tissue (ADJ), and leukocytes (LEU) from five Mexican TNBC patients. We identified both unique and shared CNVs across tissues, including alterations in key chromosomal regions such as 1q23.3, 1q32.1, and 8q24.3, which harbor oncogenes like MYC, MCL1, and BCL9. Losses in 6q25.2 affecting ESR1 were also detected. CNVs were enriched in genes related to the Hallmarks of Cancer, with TUM samples showing profiles associated with proliferation, metastasis, and immune evasion; ADJ samples with growth suppression; and LEU samples with genomic instability. Pathway enrichment analyses revealed disrupted functions in DNA repair, extracellular matrix organization, and TP53 signaling in TUM. Notably, EGFR, ERCC4, and HSP90AB1 emerged as central nodes in interaction networks and may serve as markers or therapeutic targets. This is the first CNV profiling study of its kind in TNBC from Mexican patients, highlighting the importance of including underrepresented populations in genomic research to uncover distinct molecular signatures and potential diagnostic or therapeutic avenues. ImplicationsMolecular signatures of breast cancer (BC), predicted bioinformatically, involve common and distinct CNV-Hallmarks of Cancer genes, which are suitable candidates for screening as potential BC markers.

genomics↗

bioRxiv2025

Maternal IBD-related antibodies are associated with early life gut inflammatory status and microbiota composition: insights from cord blood

PurposeAntibodies in peripheral blood are used to aid in the diagnosis of inflammatory bowel disease (IBD), but their presence in neonatal cord blood and potential effects on early life development remain unknown. MethodsWe measured anti-CBir1, ANCA, anti-OmpC, ASCA IgA, and ASCA IgG levels in the cord blood of babies born to 78 mothers with or without IBD. Their association with fecal calprotectin (FC), and microbiota composition, characterized by 16S rRNA sequencing, was assessed throughout pregnancy and during the first 3 years of life using linear mixed-effects models. ResultsAntibodies were detected in cord blood, with significantly higher levels of anti-CBir1 and ASCA IgG in babies born to mothers with Crohns disease (p = 0.002) and higher abundance of ANCA and anti-OmpC in babies of mothers with ulcerative colitis (p = 0.002), compared to controls. ASCA IgG levels positively correlated with babies FC (p = 0.006), while babies microbiota Shannon diversity was negatively associated with ANCA, anti-OmpC, and ASCA IgA levels (p = 0.003, 0.04, and 0.008, respectively). Romboutsia spp., Citrobacter spp., Pseudomonas spp., Clostridiaceae, Clostridia, and Varibaculum spp. were positively correlated with either or both ANCA and anti-OmpC levels (all multiple testing adjusted q < 0.1). ConclusionOur findings suggest that maternal IBD-associated antibodies cross the placenta barrier and may be associated with intestinal inflammation and imbalanced microbiota colonization. Whether these serological profiles negatively influence the priming of the babys immune system or IBD risk later in life remains to be determined.

immunology↗

bioRxiv2025

CagY sequence and structural motifs are associated with ancestry and 1 disease in world-wide Helicobacter pylori strains

Helicobacter pylori (Hp) interacts with gastric epithelial cells using a multi-protein type 4 secretion system (T4SS) whose function is regulated by CagY. CagY is the T4SS backbone, connecting the bacterial cytoplasm with the epithelial cytoplasm and interacting with most other T4SS proteins. However, its mechanisms of action are unknown. We aimed to comprehensively analyse cagY in a worldwide collection of strains to unmask any correlation between ancestry and/or disease and sequence diversity, including an analysis of critical domains and associated structural changes. We used 674 cagY sequences derived from1,012 Hp genomes, sequenced with Single Molecule Real-Time from the Hp Genome Project. Phylogenetic and principal component analyses (PCA) revealed a strong population structure among European, Asian, African and American clusters, which interfered with other analyses. To address this heterogeneity, dimensional reduction analysis with PCA and Linear Discriminant Analyses were used to minimize interference before studying possible association of cagY diversity with disease. For this analysis, cagY genes were fragmented using unitig-caller with a designed analytical pipeline that clearly separated the non-atrophic gastritis (NAG), advanced intestinal metaplasia and gastric cancer (GC) groups. Sixty-four unitigs significantly separated GC from NAG based on cagY sequences, and the most GC-associated unitigs were localized in the middle repeat region of the protein (MRR), particularly in the A module, including the cysteine-containing motif YLDCVSQ. Proline was enriched in the MRR and VirB10 regions. The consequences of the diversity on the protein structure were analysed using ChimeraX. The validated and stabilized 14-multimer model showed major structural changes along the multimer-structure, particularly in the cysteine-rich MRR region, that might be one mechanism by which CagY regulates T4SS function.

bioinformatics↗

bioRxiv2025

Rapid acquisition of HIV-1 neutralization breadth in a rhesus V2 apex germline antibody mouse model after a single bolus immunization

Current vaccine strategies to elicit broadly neutralizing antibodies (bnAbs) against HIV-1 generally propose complex, multi-boost immunization regimens. In rhesus macaques, SHIV infection has been observed to rapidly drive the development of some classes of bnAbs that share structural similarities with those in humans. Here, we generated a knockin mouse model with B cells bearing the unmutated common ancestor (UCA) of the V2 apex-targeted bnAb lineage, V033-a. A single immunization of mice with a germline-targeting native-like trimer was sufficient to recapitulate the ontogeny of the mature rhesus bnAb in knockin mice--including rare, disfavored somatic mutations--leading to the induction of antibodies that exhibited potent neutralization against both autologous and heterologous tier 2 viruses. A boost with Env escape mutant trimers further improved breadth and potency, and cryo-EM structure revealed the structural basis for heterologous neutralization breadth. Non-human primate and mouse models can thus combine with structure to serve as a platform for identifying and confirming immunogens that streamline HIV-vaccination regimens.

immunology↗

bioRxiv2025

Effects of Willow and Pine tree growth in bacterial abundance, interactions and metabolic profile in a copper mine tailing

The Cauquenes tailings is one of the largest mine tailings in Chile and represents a significant environmental hazard due to its high copper levels and acidic pH. However, there is evidence of willow and pine tree growth in these terrains, which is unexpected given the extreme conditions of this environment. Considering the importance of plants in restoration strategies, the objective of this study was to analyze the effect that willow and pine growth have on the heavy metal contents of their surrounding soil, and the abundance, interaction, metabolic profile and assembly of the bacterial community. In the Cauquenes tailing, we collected samples from willow and pine vegetated soils as well as the surrounding non-vegetated soils. We analyzed characteristics such as heavy metal concentrations and pH levels in all sampled soils, and in tree leaves and roots. Vegetated sites exhibited lower copper levels and a neutral pH, while both tree species accumulated heavy metals in their tissues. We also determined bacterial abundance in all soil samples, and co-occurrence networks were constructed to assess bacterial interactions. Both trees promoted a higher abundance of Proteobacteria and had networks with higher modularity compared to non-vegetated soils. Finally, we estimated the metabolic profile of the bacterial community using PICRUSt 2 analysis and determined carbon source utilization with BioLog Ecoplates. PICRUSt 2 predicted higher metabolic activity in vegetated soils, and BioLog Ecoplate analysis revealed the utilization of a greater number of carbon sources. The microbial communities from vegetated soils were assembled in a deterministic manner, while the community from non-vegetated soils were stochastically assembled. In conclusion, tree growth mitigated the extreme conditions of the tailing and promoted a more active and healthier bacterial community. HighlightsO_LIWillow and pine tree can grow and mitigate toxic metal conditions in the tailings C_LIO_LIBoth trees provoked a shift in bacterial abundance and interaction network C_LIO_LIThe provoked shift was tree-dependent C_LIO_LIMicrobial activity was higher in vegetated soils C_LI

microbiology↗

bioRxiv2025

Bioprospection of culturable soil-borne bacteria with biotechnological potential for use in priming defense

BackgroundThe plant root microbiome is central to disease resistance and stress resilience. In intensive tomato production, prolonged agrochemical use disrupts microbial communities, reducing their protective functions and enabling pathogen establishment. MethodsWe integrated 16S rRNA amplicon sequencing with culture-dependent isolation to analyze microbiome shifts in tomato plants across healthy, asymptomatic, and symptomatic states in a nematode-infested field. Network analysis and machine learning were used to identify key taxa. Isolates were screened for plant growth-promoting rhizobacteria (PGPR) and nematicidal activity, and selected strains were evaluated in planta under pathogen challenge. ResultsMicrobial diversity and community complexity declined with disease severity. Gaiella occulta emerged as a potential biomarker of plant health. From 223 isolates, 45 strains exhibited PGPR and nematicidal traits. Ten were tested in tomato plants, where treatments conferred systemic resistance to Pseudomonas syringae pv tomato without fitness cost. Four strains, primarily Pseudomonas and Bacillus, triggered immune priming, enhanced root development, and three of them were co-isolated from a single asymptomatic plant. ConclusionsOur findings highlight the potential of targeted bacterial consortia to restore microbiome balance and activate immune responses in tomato. These results support the rational design of synthetic microbial communities (SynComs) for sustainable, microbiome-based crop protection.

immunology↗

bioRxiv2025

The oral cavity of chronically homeless adults is home for unusual extremophile environmental bacteria

Chronically homeless adults (CHA) often face limited healthcare access, poor nutrition, frequent substance use, and close contact with stray animals. These factors can significantly alter their oral microenvironment. This study aimed to characterize the oral microbiota of this vulnerable and understudied population. We analyzed saliva samples from 60 chronically homeless men and 40 asymptomatic men with no history of homelessness, all living in Mexico City. DNA was extracted, and the V1-V3 regions of the 16S rRNA gene were sequenced. Taxonomic classification was performed using human and non-human databases. Diversity metrics were calculated using the vegan v2.6-4 package in R, and informative species were identified through machine learning and statistical approaches. Microbial correlation networks were inferred using NetCoMi in RStudio. Bacterial diversity was significantly higher in the CHA group. While both groups shared 369 species, only eight were exclusive to the control group, and 149 were unique to CHA. Several of these taxa had never been reported in humans and are typically found in extreme environments. For example, Megasphaera cerevisiae, adapted to high ethanol and low pH, was the most abundant species. Syntrophocurvum alkaliphilum, from a hypersaline lake in Siberia, and Sinanaerobacter chloroacetimidivorans, from anaerobic bioreactors, were also prevalent. Marked differences in microbial network structure were observed between groups. These findings highlight the adaptability of extremophile bacteria to human environments under chronic stress and poor hygiene. This study provides a first look into the oral microbiota of individuals experiencing chronic homelessness, emphasizing the need for more research into marginalized populations.

bioinformatics↗

bioRxiv2025

Reduced glutathione levels in Enterococcus faecalis trigger metabolic and transcriptional compensatory adjustments during iron exposure.

Enterococcus faecalis, a facultative anaerobic pathogen and common constituent of the gastrointestinal microbiota, must navigate varying iron levels within the host. This study explores its response to iron supplementation in a glutathione-deficient mutant strain ({Delta}gsh). We examined the transcriptomic and metabolic responses of a glutathione synthetase mutant strain ({Delta}gsh) exposed to iron supplementation, integrating these data into a genome-scale metabolic model (GSMM). Our results show that under glutathione deficiency, E. faecalis reduces intracellular iron levels and shifts its transcriptional response to prioritize energy production genes. Notably, basal metabolites, including arginine, increase. The GSMM highlights the importance of arginine metabolism, particularly the arc operon (anaerobic arginine catabolism), as a compensatory mechanism for reduced glutathione during iron exposure. These findings provide insights into how E. faecalis adjusts metal homeostasis and transcriptional/metabolic processes to mitigate the effects of oxidative stress caused by iron. IMPORTANCEIron is essential for bacterial survival, yet its excess can be harmful through increase of oxidative stress. Enterococcus faecalis, a bacterium common member of the human gut, must carefully balance its iron levels in order to survive in changing environments. This study studies how E. faecalis compensates the reduced levels of glutathione --a key antioxidant-- when exposed to high iron concentrations. We discovered that E. faecalis lowers its intracellular iron levels under glutathione decrease and reprograms its metabolism to prioritize energy production. These findings provide valuable insights into bacterial adaptation mechanisms under oxidative stress conditions, which could influence the development of new strategies to combat bacterial infections.

systems biology↗

bioRxiv2025

Heritable viral symbionts in the family Iflaviridae are widespread among aphids

AO_SCPLOWBSTRACTC_SCPLOWHeritable microbes shape host phenotypes and are important drivers of evolution. While interactions between insects and bacterial symbionts have been extensively studied, the prevalence and consequences of insect-viral symbiosis are an open question. We show that viral symbionts in the family Iflaviridae are widespread among aphids, an important model for research on bacterial symbiosis. We discovered multiple new species of iflaviruses that are maintained in asexual lines without apparent fitness costs and are transmitted vertically from mothers to offspring. Using field data and phylogenetic evidence, we further show that aphid iflaviruses likely move horizontally across species, but through laboratory experiments, we demonstrated that horizontal transfer among species infesting the same host plants does not persist throughout clonal lineages. Using quantitative PCR and immunohistochemistry, we discovered that viral infections localize in the host fat bodies and developing embryos. Surprisingly, we also found viral infections inside bacteria-housing cells called bacteriocytes, with a positive correlation between viral and bacterial symbiont density, indicating a mechanism for vertical transmission. Together, our work suggests that iflaviruses are an important but previously unrecognized piece of aphid symbiosis and sets the stage to use this model to answer new questions about host-microbe associations. IO_SCPLOWMPORTANCEC_SCPLOWIn recent years, the rise of metatranscriptome sequencing has led to the rapid discovery of novel viral sequences in insects. However, few studies have carefully investigated the dynamics of insect-virus interactions to produce a general understanding of viral symbiosis. Aphids are a significant agricultural pest but also an important model for understanding the evolution of host-microbe interactions and the molecular basis of bacterial symbiosis. We show that heritable iflaviruses are an important but previously unrecognized part of the aphid heritable microbiome, with viral symbionts transmitted alongside bacteria from mothers to offspring, potentially via specialized bacteriocytes that house symbiotic microbes. Our findings have important implications for furthering the understanding of insect-microbe symbiosis and the potential for biocontrol of agriculturally relevant pest species.

evolutionary biology↗