Project description:Biofilms are heterogeneous bacterial communities featured by high persister prevalence, responsible for antibiotic tolerance. However, the mechanisms underlying persister formation within biofilms remained ambiguous. Here, by developing and utilizing a ribosomal RNA depleted bacterial single-cell RNA-seq method, RiboD-mSPLiT, we resolved biofilm heterogeneity and discovered pdeI as a marker gene for persister subgroup within biofilms. Remarkably, our findings elucidated that PdeI upregulates cellular levels of c-di-GMP, which acts as an antitoxin to modulate the toxicity of toxin protein HipH. HipH localizes on nucleoid and functions as a potent DNase, inducing cells into a viable but non-culturable state. Conversely, c-di-GMP interacts with HipH, reducing its genotoxic effects and enabling cells to enter a persister state, resulting in drug tolerance. Importantly, by targeting this toxin-antitoxin system, we repressed drug tolerance in Uropathogenic Escherichia coli infections, offering promising therapeutic strategies against chronic and relapsing infections.
Project description:Biofilms are heterogeneous bacterial communities featured by high persister prevalence, responsible for antibiotic tolerance. However, the mechanisms underlying persister formation within biofilms remained ambiguous. Here, by developing and utilizing a ribosomal RNA depleted bacterial single-cell RNA-seq method, RiboD-mSPLiT, we resolved biofilm heterogeneity and discovered pdeI as a marker gene for persister subgroup within biofilms. Remarkably, our findings elucidated that PdeI upregulates cellular levels of c-di-GMP, which acts as an antitoxin to modulate the toxicity of toxin protein HipH. HipH localizes on nucleoid and functions as a potent DNase, inducing cells into a viable but non-culturable state. Conversely, c-di-GMP interacts with HipH, reducing its genotoxic effects and enabling cells to enter a persister state, resulting in drug tolerance. Importantly, by targeting this toxin-antitoxin system, we repressed drug tolerance in Uropathogenic Escherichia coli infections, offering promising therapeutic strategies against chronic and relapsing infections.
Project description:Biofilms are heterogeneous bacterial communities featured by high persister prevalence, responsible for antibiotic tolerance. However, the mechanisms underlying persister formation within biofilms remained ambiguous. Here, by developing and utilizing a ribosomal RNA depleted bacterial single-cell RNA-seq method, RiboD-mSPLiT, we resolved biofilm heterogeneity and discovered pdeI as a marker gene for persister subgroup within biofilms. Remarkably, our findings elucidated that PdeI upregulates cellular levels of c-di-GMP, which acts as an antitoxin to modulate the toxicity of toxin protein HipH. HipH localizes on nucleoid and functions as a potent DNase, inducing cells into a viable but non-culturable state. Conversely, c-di-GMP interacts with HipH, reducing its genotoxic effects and enabling cells to enter a persister state, resulting in drug tolerance. Importantly, by targeting this toxin-antitoxin system, we repressed drug tolerance in Uropathogenic Escherichia coli infections, offering promising therapeutic strategies against chronic and relapsing infections.
Project description:Biofilm-related diseases are typically persistent infections, and a challenge for medical treatment. Biofilms are communities of bacteria that attach to surfaces and are enclosed in an extracellular matrix. These sessile microorganisms can endure external stresses like nutrient deprivation, antibiotic treatments, and immune defences. Therefore, biofilms create conditions favourable for bacterial pathogenesis. The knowledge of novel biofilm regulators may contribute to develop new strategies to fight microbial infections. In this work we study the role of the RNA-binding protein and RNA-degradative enzyme polynucleotide phosphorylase (PNPase) from the human pathogen Listeria monocytogenes. We show that inactivation of Listeria PNPase not only leads to strong defects in biofilm production, but also affects biofilm morphology. RNA-seq analysis of the RNA extracted from biofilms of the wild-type and the PNPase mutant strains revealed major changes in the expression of genes affecting the metabolism of carbon. Lastly, infection assays in eukaryotic cell lines confirmed that PNPase deletion leads to the severe attenuation of Listeria monocytogenes pathogenicity. Overall, our results show that PNPase is a novel regulator of biofilm formation and human cellular invasion of a bacterial pathogen. This work presents PNPase as a new and attractive target for the control of bacterial infection and highlights the expanding role of RNA-binding proteins as critical players in pathogenicity.
Project description:Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for three days then challenged with respective antibiotics (ciprofloxacin, daptomycin, tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites including 18 amino acids, glucose, lactate, acetate, formate, and ethanol were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of microorganisms in biofilms contributing to antibiotic tolerance. The Acinetobacter baumannii microarray data from the study described above is deposited here.
Project description:Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for three days then challenged with respective antibiotics (ciprofloxacin, daptomycin, tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites including 18 amino acids, glucose, lactate, acetate, formate, and ethanol were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of microorganisms in biofilms contributing to antibiotic tolerance. The Staphylococcus aureus microarray data from the study described above is deposited here.
Project description:Multispecies biofilms consist of complex communities where extracellular polymeric substances (EPS) are vital in their structure, adaptability, and function. However, characterizing the components of EPS, particularly glycans and proteins, remains a challenge due to the diverse species and their interactions within the matrix. This study examined how interactions between different species affect EPS components' production and spatial organization. We utilized a consortium of four bacterial soil isolates that have previously demonstrated various intrinsic properties in biofilm communities: Microbacterium oxydans, Paenibacillus amylolyticus, Stenotrophomonas rhizophila, and Xanthomonas retroflexus. We used fluorescence lectin-binding analysis (FLBA) to identify specific glycan components and meta-proteomics to characterize matrix proteins in mono- and multispecies biofilms. Our results revealed diverse glycan structures and compositions, including fucose and different amino sugar-containing polymers, with substantial differences between monospecies and multispecies biofilms. In isolation, M. oxydans produced galactose/N-Acetylgalactosamine network-like structures and influenced the matrix composition in multispecies biofilms. Proteomic analysis revealed flagellin proteins in Xanthomonas and Paenibacillus, particularly in multispecies biofilms. Additionally, surface-layer proteins and a unique peroxidase were found in P. amylolyticus multispecies biofilms, indicating enhanced oxidative stress resistance and structural stability under these conditions. This study highlights the crucial role of interspecies interactions in shaping biofilm matrices and the production of glycans and proteins. These findings deepen our understanding of biofilm complexity and may lead to new approaches for controlling biofilms in various environments.
Project description:The physiological and transcriptional response of Nitrosomonas europaea biofilms to phenol and toluene was examined and compared to suspended cells. Biofilms were grown in Drip Flow Biofilm Reactors under continuous flow conditions of growth medium containing ammonia as growth substrate. The responses of N. europaea biofilms to the aromatic hydrocarbons phenol and toluene were determined during short-term (3 h) additions of each compound to the biofilms. Ammonia oxidation in the biofilms was inhibited 50% by 60 uM phenol and 100 uM toluene. These concentrations were chosen for microarray analysis of phenol- and toluene-exposed N. europaea biofilms. Liquid batch cultures of exponentially growing N. europaea cells were harvested alongside the biofilms to determine differential gene expression between attached and suspended growth of N. europaea.
2010-07-20 | GSE22646 | GEO
Project description:Bacterial communities of streambed sediments