Abstract Bacterial populations are highly adaptive. They can respond to stress and survive in shifting environments. How the behaviours of individual bacteria vary during stress, however, is poorly understood. To identify characterize rare bacterial subpopulations, technologies for single-cell transcriptional profiling have been developed. Existing approaches show some degree limitation, example, terms number cells or transcripts that be profiled. Due part these limitations, few conditions...

Cells regularly experience fluid flow in natural systems. However, most experimental systems rely on batch cell culture and fail to consider the effect of flow-driven dynamics physiology. Using microfluidics single-cell imaging, we discover that interplay physical shear rate (a measure flow) chemical stress trigger a transcriptional response human pathogen Pseudomonas aeruginosa. In culture, cells protect themselves by quickly scavenging ubiquitous stressor hydrogen peroxide (H2O2) from...

The retractile type IV pilus (T4P) is important for virulence of the opportunistic human pathogen Pseudomonas aeruginosa . single-stranded RNA (ssRNA) phage PP7 binds to T4P and brought cell surface through retraction. Using fluorescence microscopy, we discovered that detaches T4P, which impairs motility restricts pathogen’s virulence. cryo–electron mutagenesis, optical trapping, Langevin dynamics simulation, resolved structure PP7, PP7/T4P complex showed detachment driven by affinity...

Type IV pili (TFP) function through cycles of extension and retraction. The coordination these remains mysterious due to a lack quantitative measurements multiple features TFP dynamics. Here, we fluorescently label in the pathogen Pseudomonas aeruginosa track full retraction individual filaments. Polymerization depolymerization dynamics are stochastic; made at random times extend, pause, retract for lengths time. can also pause extended periods between two or events both wild-type cells...

Significance While many bacteria can sense the presence of a surface, mechanical properties different surfaces vary tremendously and be as rigid bone or soft mucus. We show that pathogen Pseudomonas aeruginosa distinguishes by stiffness transcriptionally tunes its virulence to surface rigidity. This connection between pathogenicity infection site presents an interesting potential for clinical applications. The mechanism behind sensing relies on retraction external appendages called type IV...

Significance Bacterial migration, aggregation, and even host infection depend on the generation of mechanical force. Despite their biomedical importance, forces between bacteria surfaces have not yet been measured during migration. We present a first study bacterial cell–substrate traction using Myxococcus xanthus as model organism. M. exhibits two common mechanisms motility, namely, twitching gliding. find that these lead to distinct patterns motion an individual or in groups. Twitching...

Fluid flow is thought to prevent bacterial adhesion, but some bacteria use adhesins with catch bond properties enhance adhesion under high shear forces. However, many studies on either neglect the influence of force or forces that are not typically found in natural systems. In this study, we microfluidics and single-cell imaging examine how human pathogen Pseudomonas aeruginosa interacts surfaces when exposed body (0.1 pN 10 pN). Through cell tracking, demonstrate angle between surface...

The bacterial colonization of surfaces is a ubiquitous process that shapes nature and profoundly affects human health. While much known about the biology this process, pivotal interplay between physical environment active micromechanics remains poorly understood. In fact, strong adhesion high motility, both which are essential for surface colonization, two apparently contradictory goals, as they mutually obstruct each other. Here, we investigate how pathogen optimizes its behavior under...

Abstract Colonies of the social bacterium Myxococcus xanthus go through a morphological transition from thin colony cells to three-dimensional droplet-like fruiting bodies as strategy survive starvation. The biological pathways that control decision form body have been studied extensively. However, mechanical events trigger creation multiple cell layers and give rise droplet formation remain poorly understood. By measuring orientation, velocity, polarity, force with cell-scale resolution, we...

Bacterial populations experience chemical gradients in nature. However, most experimental systems either ignore or fail to capture mechanically relevant contexts. Here, we use microfluidic experiments and biophysical simulations explore how host-relevant shear flow affects antimicrobial across communities of the highly resistant pathogen Pseudomonas aeruginosa . We discover that patterns three chemically distinct antimicrobials: hydrogen peroxide, gentamicin, carbenicillin. Without flow, P....

The transfer of mechanical signals through cells is a complex phenomenon. To uncover new mechanotransduction pathway, we study the frequency-dependent transport stimuli by single microtubules and small networks in bottom-up approach using optically trapped beads as anchor points. We interconnected to linear triangular geometries perform micro-rheology defined oscillations relative each other. found substantial stiffening filaments above characteristic transition frequency 1-30 Hz depending...

Mechanical properties of the extracellular matrix are important determinants cellular migration in diverse processes, such as immune response, wound healing, and cancer metastasis. Moreover, recent studies indicate that even bacterial surface colonization can depend on mechanics substrate. Here, we focus physical mechanisms give rise to substrate-rigidity dependent migration. We study a "twitcher", cell driven by extension-retraction cycles, idealize bacteria perhaps eukaryotic cells employ...

Pseudomonas aeruginosa is a significant threat in both healthcare and industrial biofouling. Surface attachment of P. particularly problematic as surface association induces virulence necessary for the ensuing process biofilm formation, which hampers antibiotic treatments. Previous efforts have searched dispersal agents mature collectives, but there are no known factors that specifically disperse individual surface-attached aeruginosa. In this study, we develop quantitative single-cell...

Abstract Bacterial populations are highly adaptive. They can respond to stress and survive in shifting environments. How the behaviors of individual bacteria vary during stress, however, is poorly understood. To identify characterize rare bacterial subpopulations, technologies for single-cell transcriptional profiling have been developed. Existing approaches, though, all limited some technical capacity (e.g., number cells or transcripts that be profiled). Due part these limitations, few...

More and more Pseudomonas aeruginosa isolates have become resistant to antibiotics like carbapenem. As a consequence, P. ranks in the top three of pathogens for which development novel is most crucial. The pathogen causes both acute chronic infections, especially patients who are vulnerable. Therefore, efforts urgently needed develop alternative therapies. One path explored this article use bacteriophages and, specifically, phage-derived proteins. In study, protein was studied that impacts...

Optical traps have shown to be a flexible and powerful tool for 3D manipulations on the microscale. However, when it comes sensitive measurements of particle displacements forces thorough calibration procedures are required, which can already demanding trapped spheres. For asymmetric structures, with more complicated shapes, such as helical bacteria, novel schemes need established. The paper describes different methods how extract various parameters tiny bacterium, is tracked in shape by...

Summary In microbial communities, viruses compete for host cells to infect, and thus evolved diverse ways inhibit their competitors. One mechanism is Superinfection exclusion (Sie), whereby a virus that has established an infection prevents secondary infection. We identified Pseudomonas prophage Sie protein alters pilus dynamics through the assembly chaperone, PilZ. This protein, known as Zip Pil Z i nteracting p rotein, does not abrogate activity, but fine tunes it, providing strong phage...

Antimicrobial resistance is an emerging global threat to humanity. As outpaces development, new perspectives are required. For decades, scientists have prioritized chemical optimization, while largely ignoring the physical process of delivery. Here, we used biophysical simulations and microfluidic experiments explore how fluid flow delivers antimicrobials into communities highly resistant pathogen

Type IV pili (T4P) are thin, flexible filaments exposed on the cell surface of gram-negative bacteria and involved in pathogenesis-related processes, including adsorption, biofilm formation, twitching motility. Bacteriophages often use these as receptors to infect host cells. Here, we describe identification a protein that inhibits T4P assembly Pseudomonas aeruginosa, discovered during screen for factors influencing phage infection. We show expression PA2560 (renamed PlzR) P. aeruginosa...

Bacterial pathogenicity relies on both firm surface adhesion and cell dissemination. How twitching bacteria resolve the fundamental contradiction between migration is unknown. To address this question, we employ live-cell imaging of type-IV pili (T4P) therewith construct a comprehensive mathematical model