Pseudomonas aeruginosa PA14 biofilms produce R-bodies, extendable protein polymers with roles in host colonization and virulence

Wang, B.; Lin, Y.-C.; Jo, J.; Price-Whelan, A.; Tao McDonald, S.; Brown, L. M.; Dietrich, L. E.

doi:10.1101/2020.10.26.356394

Home/Archive/bioRxiv

bioRxiv · 10.1101/2020.10.26.356394

Pseudomonas aeruginosa PA14 biofilms produce R-bodies, extendable protein polymers with roles in host colonization and virulence

Wang, B.·Lin, Y.-C.·Jo, J.·Price-Whelan, A.·Tao McDonald, S.·Brown, L. M.·Dietrich, L. E.

View original source ↗Export metadata ↓

Abstract

Pseudomonas aeruginosa PA14, an opportunistic pathogen of diverse hosts, contains genes with the potential to confer production of R-bodies (i.e., a "reb cluster"). R-bodies are large, extendable protein polymers best known for their role in killing of paramecia by the bacterium Caedibacter taeniospiralis, and genes in the reb cluster have been implicated in PA14 virulence. Here, we present evidence that PA14 expresses reb cluster genes during colonization of plant and nematode hosts. We identify products of the reb cluster that are R-body-associated and that control stochastic expression of R-body structural genes. We also show that R-body production is required for full virulence in nematodes. Analyses of nematode ribosome content and immune response indicate that R-bodies act via a mechanism involving ribosome cleavage and translational inhibition. These observations provide insight into the biology of R-body production and its consequences during P. aeruginosa infection.

Source connections

Published article ↗

Explore related subjects

microbiology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Wang, B., Lin, Y.-C., Jo, J., Price-Whelan, A., Tao McDonald, S., Brown, L. M., Dietrich, L. E.. 2020-10-27. Pseudomonas aeruginosa PA14 biofilms produce R-bodies, extendable protein polymers with roles in host colonization and virulence. https://doi.org/10.1101/2020.10.26.356394

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Characterization of Lactobacillus rhamnosus-Derived Extracellular Vesicles and Their Cellular Cytoprotective Effects Against Trimethylamine-Induced Oxidative Stress in Caco-2 Cells

Dietary trimethylamine (TMA) underwent gut microbiota-mediated catabolism and subsequent hepatic oxidation to generate trimethylamine N-oxide (TMAO), a key metabolic factor linked to vascular and colorectal diseases. While the systemic effects of circulating TMAO were heavily investigated, the direct localized cellular interactions of its precursor, TMA, at the intestinal epithelial level required further elucidation. This study characterized extracellular vesicles isolated from Lactobacillus rhamnosus (Lr-EVs) and evaluated their cytoprotective potential in an in vitro human intestinal Caco-2 cell model under TMA-induced stress. Exposure to a high concentration of TMA (20 mM) significantly reduced Caco-2 viability to 78.8%, triggered intracellular reactive oxygen species (ROS) accumulation, and compromised tight junction integrity as observed via the disruption of Zonula Occludens-1 (ZO-1) alignment. Co-treatment with Lr-EVs (100-300 g/mL) counteracted this cellular toxicity, enhancing cell survival up to 172%. Quantitative PCR analysis revealed that Lr-EVs suppressed the transcriptional upregulation of the pro-inflammatory gene IL-1{beta}, restored the expression of the metabolic regulator SIRT1, and stabilized transcript levels of key mitochondrial-encoded electron transport chain genes (ND6, CYTB, CO1, and ATP6). Additionally, Lr-EVs exhibited intrinsic radical scavenging activities in cell-free ABTS and DPPH assays. These preliminary in vitro findings demonstrated that Lr-EVs mitigated TMA-induced cellular injury, oxidative stress, and junctional disruption at the transcriptomic level, supporting further investigation of probiotic-derived EVs as prospective cell-free functional ingredients.

microbiology↗

bioRxiv2026

Metagenomic Insights into the Fecal Microbiome, Resistome, and Mobilome of Beef Cattle in Cow-Calf Operations in Florida, United States

Food-producing animals are a focus of One Health approaches to antimicrobial resistance (AMR) as reservoirs of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs). We hypothesized that microbial composition, ARGs profiles, and mobile genetic element (MGE) profiles would differ by operation size and animal age group. Fecal samples from 162 cows and calves were combined into 54 composite samples, each comprising three animals of the same age group. Across operation sizes, Bacillota (51.4-64.9%), Bacteroidota (12.0-17.3%), Pseudomonadota (10.3-16.5%), and Actinomycetota (3.3-10.9%) were predominant phyla. Alpha diversity did not differ among operation sizes; however, cows exhibited greater observed richness, Shannon diversity, and Simpson diversity than calves (all P < 0.001). Microbial composition did not differ significantly among operation sizes (PERMANOVA, R{superscript 2} = 0.065, P = 0.609) but differed significantly between cows and calves (R{superscript 2} = 0.200, P < 0.001). Seventy-five ARGs representing 14 resistance classes were identified. Normalized ARG hit rates were higher in small operations (0.444) than in medium (0.278) and large operations (0.222; P = 0.088), whereas calves exhibited a higher estimated marginal mean normalized ARG hit rate than cows (0.383 vs. 0.247 hits/million reads; P < 0.001). Of 1,054 curated ARG hits, 23.9% occurred on predicted plasmid contigs, 0.9% on predicted viral contigs, and 7.1% on contigs containing insertion sequences. Overall findings demonstrate differences in fecal microbiome diversity and ARG abundance between cows and calves and indicate that predicted plasmids are associated with a notable proportion of ARG hits in Florida beef cow-calf operations.

microbiology↗

bioRxiv2026

A global post-transcriptional regulator directs Acinetobacter baumannii carbon preference and gut colonization

Acinetobacter baumannii is a multidrug-resistant pathogen that colonizes the gut, increasing the risk of subsequent infection and transmission. Recent work showed that A. baumannii catabolizes ornithine, a non-preferred carbon source, to colonize the gut. However, the mechanisms of carbon preference were unknown in A. baumannii. Here, experimental evolution identified the conserved RNA-binding protein CsrA as a regulator of carbon preference in A. baumannii, a previously unreported CsrA function. RNA immunoprecipitation sequencing (RIP-Seq) revealed hundreds of CsrA-associated transcripts. A. baumannii CsrA directly bound and repressed expression of the ast arginine/ornithine catabolic operons. The Pseudomonas aeruginosa CsrA homolog RsmA repressed arginine/ornithine catabolic operon expression, suggesting this CsrA function extends to other bacterial taxa. Finally, CsrA was required for competitive fitness during A. baumannii gut colonization. These findings uncover a previously unrecognized role for a global regulator in A. baumannii carbon preference and persistence in the gut, a critical reservoir for multidrug-resistant pathogens.

microbiology↗