Biology subjects

Armbruster, C. R.

Publications and source records attributed to Armbruster, C. R..

10 recordsLinked to original sources

bioRxiv2026

MagicLamp: a web server and software toolkit for targeted gene annotation of microbial functions

Genome and metagenome annotation tools designed for large databases are ill-suited to the discovery of specialized, ecologically relevant microbial functions. MagicLamp (https://github.com/Arkadiy-Garber/MagicLamp) is a modular command-line software toolkit that performs targeted functional gene annotation searches using curated collections of hidden Markov models (HMMs), each representing discrete microbial metabolic processes. MagicLamp is also available as a web server: https://midauthorbio.com/#magiclamp. This targeted approach enables sensitive and specific annotation of genes involved in defined microbial processes, allowing MagicLamp to serve as a dedicated repository for the annotation of specialized microbial functions currently overlooked in other databases and software. The server accepts unannotated genome assemblies or GenBank-formatted annotations to perform HMM-based searches against curated model sets with reproducible, model-specific bit-score thresholds. Automated results are returned as tabular summaries and interactive HTML reports containing cross-genome/metagenome comparisons.

bioinformatics↗

bioRxiv2026

BTEXgenie: A curated and user-friendly tool for profile HMM-based substrate-specific annotation of BTEX degradation genes

BackgroundBenzene, toluene, ethylbenzene, and xylene (BTEX) are volatile aromatic hydrocarbons that are widespread environmental pollutants arising from petroleum processing, fuel combustion, and other industrial activities. Persistent BTEX contamination poses substantial risks to human health and ecosystems, underscoring the need for effective long term remediation strategies. Microbial bioremediation is a promising and sustainable approach for BTEX removal, but development of these approaches requires accurate detection of the genes and pathways responsible for substrate specific degradation. Although profile hidden Markov model (HMM) databases are widely used for functional annotation, existing annotation resources lack the substrate-specific resolution needed to distinguish between closely-related BTEX-degrading enzymes with different catalytic specificities. ResultsWe developed BTEXgenie as a sensitive annotation tool that uses custom HMMs built from alignments of experimentally validated BTEX degradation proteins to identify genes involved in the initial steps of aerobic and anaerobic BTEX degradation. BTEXgenie improved detection of anaerobic BTEX degradation genes that were absent from KOfam annotations. In benchmarking against the KEGG KOfam HMM database, BTEXgenie achieved 17.73%higher overall sensitivity while maintaining comparable specificity at 97.02%across genes involved in BTEX degradation pathways. When applied to environmental metagenomes, BTEXgenie recovered pathway patterns consistent with reported site characteristics and known degradation potential. In addition to gene annotation, BTEXgenie supports downstream interpretation through KEGG pathway-based visualization of detected functions and Circos-based visualization of genomic hit distributions. ConclusionsBTEXgenie is a substrate-specific annotation tool built from custom HMMs for detecting genes involved in BTEX degradation. By integrating gene annotation with pathway and genome-level visualizations, BTEXgenie facilitates characterization of microbial BTEX degradation potential in environmental and comparative genomic studies.

bioinformatics↗

bioRxiv2025

Respiratory viral infection is associated with increased Pseudomonas abundance in cystic fibrosis airways

Acute respiratory viral infections are an important driver of morbidity and mortality in people with chronic lung disease and are frequently associated with pulmonary exacerbations and a transition from intermittent to chronic bacterial infection of the airways. Chronic Pseudomonas aeruginosa infections are associated with worsened lung function, poor outcomes, and increased hospital visits. We sought to improve understanding of the effects of respiratory viral infections and host immune response on the resident bacterial community of the airways, using cystic fibrosis as a model. We performed an observational longitudinal study of 38 adults with CF and collected sinus and sputum samples at 6-month intervals from 2017 - 2021. We performed 16S rRNA amplicon sequencing to characterize the airway microbiota, real-time RT-PCR for viral infection detection, and cytokine quantification. We observed viral positivity rates of 19% and 14% in sinus and sputum samples, respectively. Human rhinovirus was the most frequently observed viral pathogen in both sinus and sputum samples. We measured a significant perturbance of the bacterial community during viral infection that did not return to baseline following resolution of the viral infection. This perturbation was driven by a significant increase in Pseudomonas relative abundance during viral infection. Furthermore, we found significant associations with increased Pseudomonas relative abundance for several pro-inflammatory and antiviral cytokines, including interleukin (IL)-2, IL-8, and interferon (IFN)-{lambda}1. These findings indicate an important role for respiratory viral infections and the host immune response in the development and maintenance of chronic Pseudomonas infections in the context of CF airway disease and broadly expand our understanding of viral-bacterial coinfection of the airways. IMPORTANCERespiratory infections are a leading cause of morbidity and mortality worldwide, and co-infections are associated with worsened disease outcomes. In viral-bacterial co-infection, clinical and mechanistic studies show that a preceding acute respiratory viral infection promotes the establishment and exacerbation of bacterial infections, leading to increased morbidity. Although people with cystic fibrosis do not experience more frequent acute respiratory viral infections, their outcomes are worse, with prolonged symptoms and hospitalizations. When examining how acute viral infections shape the microbiota in the respiratory tract of pwCF, we observe a disturbance of the microbial community composition during viral infections that does not return to baseline after the acute viral infection resolves. Moreover, we show that Pseudomonas relative abundance is significantly increased in the airways of pwCF during viral infection and that increased concentrations of antiviral cytokines - such as interferon (IFN)-{lambda}1 - are associated with increased Pseudomonas abundance. These findings offer evidence that the progression of chronic Pseudomonas infections in pwCF are influenced by acute respiratory viral infections and the subsequent antiviral response in the airways. This study furthers our understanding of viral-bacterial coinfection in the context of CF.

microbiology↗

bioRxiv2024

Lytic bacteriophages interact with respiratory epithelial cells and induce the secretion of antiviral and proinflammatory cytokines

Phage therapy is a therapeutic approach to treat multidrug resistant infections that employs lytic bacteriophages (phages) to eliminate bacteria. Despite the abundant evidence for its success as an antimicrobial in Eastern Europe, there is scarce data regarding its effects on the human host. Here, we aimed to understand how lytic phages interact with cells of the airway epithelium, the tissue site that is colonized by bacterial biofilms in numerous chronic respiratory disorders. We determined that interactions between phages and epithelial cells depend on specific phage properties as well as physiochemical features of the microenvironment. Although poor at internalizing phages, the airway epithelium responds to phage exposure by changing its transcriptional profile and secreting antiviral and proinflammatory cytokines that correlate with specific phage families. Overall, our findings indicate that mammalian responses to phages are heterogenous and could potentially alter the way that respiratory local defenses aid in bacterial clearance during phage therapy. Thus, besides phage receptor specificity in a particular bacterial isolate, the criteria to select lytic phages for therapy should be expanded to include mammalian cell responses.

microbiology↗

bioRxiv2023

Pseudomonas aeruginosa senses and responds to epithelial potassium flux via Kdp operon to promote biofilm biogenesis

Mucosa-associated biofilms are associated with many human disease states, but the mechanisms by which the host promotes biofilm biogenesis remain unclear. In chronic respiratory diseases like cystic fibrosis (CF), Pseudomonas aeruginosa establishes chronic infection through biofilm formation. P. aeruginosa can be attracted to interspecies biofilms through potassium currents emanating from the biofilms. We hypothesized that P. aeruginosa could, similarly, sense and respond to the potassium efflux from human airway epithelial cells (AECs) to promote biofilm biogenesis. Using respiratory epithelial co-culture biofilm imaging assays of P. aeruginosa grown in association with CF bronchial epithelial cells (CFBE41o-), we found that P. aeruginosa biofilm biogenesis was increased by potassium efflux from AECs, as examined by potentiating large conductance potassium channel, BKCa (NS19504) potassium efflux. This phenotype is driven by increased bacterial attachment and increased coalescence of bacteria into aggregates. Conversely, biofilm formation was reduced when AECs were treated with a BKCa blocker (paxilline). Using an agar-based macroscopic chemotaxis assay, we determined that P. aeruginosa chemotaxes toward potassium and screened transposon mutants to discover that disruption of the high-sensitivity potassium transporter, KdpFABC, and the two-component potassium sensing system, KdpDE, reduces P. aeruginosa potassium chemotaxis. In respiratory epithelial co-culture biofilm imaging assays, a KdpFABCDE deficient P. aeruginosa strain demonstrated reduced biofilm growth in association with AECs while maintaining biofilm formation on abiotic surfaces. Collectively, these data suggest that P. aeruginosa biofilm formation can be increased by attracting bacteria to the mucosal surface via a potassium gradient and enhancing coalescence of single bacteria into microcolonies through aberrant AEC potassium efflux sensed through the bacterial KdpFABCDE system. These findings suggest that electrochemical signaling from the host can amplify biofilm biogenesis, a novel host-pathogen interaction, and that potassium flux could be a potential target for therapeutic intervention to prevent chronic bacterial infections in diseases with mucosa-associated biofilms, like CF. Author SummaryBiofilm formation is important for Pseudomonas aeruginosa to cause chronic infections on epithelial surfaces during respiratory diseases, like cystic fibrosis (CF). The host factors that promote biofilm formation on host surfaces are not yet fully understood. Potassium signals from biofilms can attract P. aeruginosa, but it is unknown if potassium from the human cells can influence P. aeruginosa biofilm formation on a host surface. We found that P. aeruginosa biofilm formation on human airway cells can be increased by the potassium currents from airway cells, and determined bacterial genes related to potassium uptake and sensing that contribute to biofilm formation on airway cells. These findings suggest that P. aeruginosa can respond to host potassium signals by forming increased biofilm and that reducing chronic infections may be accomplished by reducing potassium coming from airway cells or blocking the bacterial proteins responsible for the biofilm enhancement by potassium currents.

microbiology↗

bioRxiv2022

Low diversity and instability of the sinus microbiota over time in adults with cystic fibrosis

BackgroundChronic rhinosinusitis (CRS) is a common, yet underreported and understudied manifestation of upper respiratory disease in people with cystic fibrosis (CF). There are currently no standard of care guidelines for the management of CF CRS, but treatment of upper airway disease may ameliorate lower airway disease. We sought to inform future treatment guidelines by determining whether changes to sinus microbial community diversity and specific taxa known to cause CF lung disease are associated with increased respiratory disease and inflammation. MethodsWe performed 16S rRNA gene sequencing, supplemented with cytokine analyses, microscopy, and bacterial culturing, on samples from the sinuses of 27 adults with CF CRS at the University of Pittsburghs CF Sinus Clinic. At each study visit, participants underwent endoscopic paranasal sinus sampling and clinical evaluation. We identified key drivers of microbial community composition and evaluated relationships between diversity and taxa with disease outcomes and inflammation. FindingsSinus community diversity was low and the composition was unstable, with many participants exhibiting alternating dominance between Pseudomonas aeruginosa and Staphylococci over time. Despite a tendency for dominance by these two taxa, communities were highly individualized and shifted composition during exacerbation of sinus disease symptoms. Exacerbations were also associated with communities dominated by Staphylococcus spp. Reduced microbial community diversity was linked to worse sinus disease and the inflammatory status of the sinuses (including increased IL-1{beta}). Increased IL-1{beta} was also linked to worse sinus endoscopic appearance, and other cytokines were linked to microbial community dynamics. InterpretationTo our knowledge, this is the largest longitudinal study of microbial communities and cytokine secretion in CF CRS. Our work revealed previously unknown instability of sinus microbial communities and a link between inflammation, lack of microbial community diversity, and worse sinus disease. FundingCystic Fibrosis Foundation and US National Institutes of Health. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSA search of the PubMed database on October 11, 2021 with the terms [cystic fibrosis sinus microbiome] yielded 16 results, and we have identified seven primary research articles on the CF CRS microbiome (including re-analyses of existing datasets). Most are cross-sectional cohort analyses, along with one prior longitudinal study of four adults at the University of Auckland, New Zealand. Together, these prior studies reveal similarities between CF CRS and CF sputum microbiomes, including low community diversity associated with sinus disease, the presence of common CF-associated microbes in the sinuses, and prevalence of sinus communities dominated by P. aeruginosa or Staphylococcus aureus. High levels of IL-1{beta} are linked to the presence of nasal polyps in CF CRS, and polymorphisms in the IL-1 receptor antagonist gene are associated with risk of CRS outside of the context of CF. Two prior studies of this cohort have been performed by our laboratory. One describes clinical indicators of CF sinus disease and the other links sinus infection biogeography to P. aeruginosa evolutionary genomics. Added value of this studyOur study is the first to examine longitudinal relationships between the host immune response (through cytokine profiling) and microbiota dynamics in CF CRS, including linking elevated IL-1{beta} to worse sinus disease through reduced sinus microbial community diversity. The longitudinal nature of our study also allowed us to uncover striking temporal instability of microbial communities in approximately half of our cohorts sinus microbial communities over two years, including switching between communities dominated by P. aeruginosa and Staphylococcus spp. This instability could hinder attempts to link the relative abundance of taxa to clinical outcomes of interest in cross-sectional studies (e.g., markers of disease progression). We also identified patterns of synergy and antagonism between specific taxa, and impacts of the host immune response in the sinuses on community composition. Implications of all the available evidenceTogether with prior CF CRS microbiome studies, our study underscores similarities between sinus and lower respiratory tract microbial community structure in CF, and we show how community structure tracks with inflammation and several disease measures. This work strongly suggests that clinical management of CRS could be leveraged to improve overall respiratory health in CF. Our work implicates elevated IL-1{beta} in reduced microbiota diversity and worse sinus disease in CF CRS, suggesting applications for existing therapies targeting IL-1{beta}. Finally, the widespread use of highly effective CFTR modulator therapy has led to less frequent availability of spontaneous expectorated sputum for microbiological surveillance of lung infections. A better understanding of CF sinus microbiology could provide a much-needed alternative site for monitoring respiratory infection status by important CF pathogens.

microbiology↗

bioRxiv2021

SprayNPray: user-friendly taxonomic profiling of genome and metagenome contigs

Shotgun sequencing of cultured microbial isolates/individual eukaryotes (whole-genome sequencing) and microbial communities (metagenomics) has become commonplace in biology. Very often, sequenced samples encompass organisms spanning multiple domains of life, necessitating increasingly elaborate software for accurate taxonomic classification of assembled sequences. While many software tools for taxonomic classification exist, SprayNPray offers a quick and user-friendly, semiautomated approach, allowing users to separate contigs by taxonomy (and other metrics) of interest. Easy installation, usage, and intuitive output, which is amenable to visual inspection and/or further computational parsing, will reduce barriers for biologists beginning to analyze genomes and metagenomes. This approach can be used for broad-level overviews, preliminary analyses, or as a supplement to other taxonomic classification or binning software. SprayNPray profiles contigs using multiple metrics, including closest homologs from a user-specified reference database, gene density, read coverage, GC content, tetranucleotide frequency, and codon-usage bias. The output from this software is designed to allow users to spot-check metagenome-assembled genomes, identify, and remove contigs from putative contaminants in isolate assemblies, identify bacteria in eukaryotic assemblies (and vice-versa), and identify possible horizontal gene transfer events.

bioinformatics↗

bioRxiv2020

Evolution and adaptation of Pseudomonas aeruginosa in the paranasal sinuses of people with cystic fibrosis

People with the genetic disorder cystic fibrosis (CF) harbor lifelong respiratory infections, with morbidity and mortality frequently linked to chronic lung infections dominated by the opportunistically pathogenic bacterium Pseudomonas aeruginosa. During chronic CF lung infections, a single clone of P. aeruginosa can persist for decades and dominate end-stage CF lung disease due to its propensity to adaptively evolve to the respiratory environment, a process termed "pathoadaptation". Chronic rhinosinusitis (CRS), chronic inflammation and infection of the sinonasal space, is highly prevalent in CF and the sinuses may serve as the first site in the respiratory tract to become colonized by bacteria that then proceed to seed lung infections. We identified three evolutionary genetic routes by which P. aeruginosa evolves in the sinuses of people with CF, including through the evolution of mutator lineages and proliferative insertion sequences and culminating in early genomic signatures of host-restriction. Our findings raise the question of whether a significant portion of the pathoadaptive phenotypes previously thought to have evolved in response to selective pressures in the CF lungs may have first arisen in the sinuses and underscore the link between sinonasal and lung disease in CF. Graphical abstract and highlightsO_LIPseudomonas aeruginosa undergoes adaptive evolution in the sinuses of people with CF C_LIO_LIOver time, pathoadapted strains display early signatures of genome degradation consistent with recent host restriction C_LIO_LIMutations previously thought to occur in CF lungs may have first evolved in sinuses C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/359844v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@13b36aborg.highwire.dtl.DTLVardef@8230e1org.highwire.dtl.DTLVardef@1570c3eorg.highwire.dtl.DTLVardef@1e4e530_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2019

Phenotypic differences in reversible attachment behavior reveal distinct P. aeruginosa surface colonization strategies

Despite possessing the machinery to sense, adhere to, and proliferate on surfaces, it is commonly observed that bacteria initially have a difficult time attaching to a surface. Before forming a bacterial biofilm, planktonic bacteria exhibit a random period of transient surface attachment known as \"reversible attachment\" which is poorly understood. Using community tracking methods at single-cell resolution, we examine how reversible attachment progresses during initial stages of surface sensing. Pseudomonas aeruginosa strains PAO1 and PA14, which exhibit similar exponential trends of surface cell population increase, show unanticipated differences when the behavior of each cell was considered at the full lineage level and interpreted using the unifying quantitative framework of an exactly solvable stochastic model. Reversible attachment comprises two regimes of behavior, processive and nonprocessive, corresponding to whether cells of the lineage stay on the surface long enough to divide, or not, before detaching. Stark differences between PAO1 and PA14 in the processive regime of reversible attachment suggest the existence of two complementary surface colonization strategies, which are roughly analogous to \"immediate-\" vs \"deferred-gratification\" in a prototypical cognitive-affective processing system. PAO1 lineages commit relatively quickly to a surface compared to PA14 lineages. PA14 lineages allow detaching cells to retain memory of the surface so that they are primed for improved subsequent surface attachment. In fact, it is possible to identify motility suppression events in PA14 lineages in the process of surface commitment. We hypothesize that these contrasting strategies are rooted in downstream differences between Wsp-based and Pil-Chp-based surface sensing systems.

microbiology↗

bioRxiv2019

Heterogeneity in surface sensing produces a division of labor in Pseudomonas aeruginosa populations

The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition from planktonic to biofilm growth in many bacterial species. Pseudomonas aeruginosa has two surface sensing systems that produce c-di-GMP in response to surface adherence. The current thinking in the field is that once cells attach to a surface, they uniformly respond with elevated c-di-GMP. Here, we describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in surface motility, allowing for exploration of the surface. We also show that this heterogeneity strongly correlates to surface behavior for descendent cells. Together, our results suggest that after surface attachment, P. aeruginosa engages in a division of labor that persists across generations, accelerating early biofilm formation and surface exploration.

microbiology↗