Article
Multidisciplinary Sciences
Matthias D. Koch, Chenyi Fei, Ned S. Wingreen, Joshua W. Shaevitz, Zemer Gitai
Summary: Researchers labeled TFP in Pseudomonas aeruginosa and tracked extension and retraction cycles of individual filaments, finding that dynamics are stochastic and TFP can pause between extension or retraction events. They developed a biophysical model based on stochastic binding of extension and retraction motors, showing that the retraction motor dictates pilus production rate and is bound to pilus machines even in their unpiliated state. JSNameOur model quantitatively agrees with a variety of experiments, suggesting that the competition of stochastic motor binding to the pilus machine coordinates the repetitive cycle of pilus extension and retraction.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Microbiology
Miaoxiao Wang, Xiaoli Chen, Yinyin Ma, Yue-Qin Tang, David R. Johnson, Yong Nie, Xiao-Lei Wu
Summary: Microbes in biofilms form spatial patterns and intermixing is an important determinant of community-level properties. This study investigates how spatial patterning and intermixing are influenced by the type IV pilus in an engineered synthetic consortium. The findings demonstrate the role of type IV pilus in mitigating spatial intermixing and provide insights for the engineering of high-performance synthetic microbial communities in spatially structured environments.
MICROBIOLOGY SPECTRUM
(2022)
Article
Microbiology
Pratick Khara, Liqiang Song, Peter J. Christie, Bo Hu
Summary: The study reveals the central roles of bacterial type IV secretion systems (T4SSs) in antibiotic resistance spread and virulence. By using CryoET, the structure of the plasmid pKM101-encoded T4SS in its native context was solved. The findings highlight the importance of comparative in vitro and in vivo analyses of T4SS nanomachines and support targeting the VirB4 ATPases as potential strategies for suppressing the action of T4SS nanomachines.
Article
Biochemistry & Molecular Biology
Souvik Naskar, Michael Hohl, Matteo Tassinari, Harry H. Low
Summary: The type II secretion system (T2SS) is a multi-protein complex used by bacteria to move substrates across their cell membrane, playing important roles in nutrient acquisition, biofilm formation, and pathogenicity. While advances in cryo-electron microscopy have provided insights into the structure and mechanism of T2SS, key questions remain regarding pseudopilus extension, retraction, and substrate movement through the system. The T2SS is part of an ancient type IV filament superfamily with implications for related systems.
MOLECULAR MICROBIOLOGY
(2021)
Article
Microbiology
Sebastian Kraus-Roemer, Isabelle Wielert, Isabel Rathmann, Jan Grossbach, Berenike Maier
Summary: This study directly visualized the dynamics of gonococcal T4P and found that they are produced at a remarkably high rate in the absence of stress. Treatment with antibiotics or external stresses reduced T4P production. The findings suggest that the downregulation of T4P extrusion complexes and cellular energy depletion contribute to reduced piliation.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Microbiology
Christine Hehnly, Aiqin Shi, Paddy Ssentongo, Lijun Zhang, Albert Isaacs, Sarah U. Morton, Nicholas Streck, Petra Erdmann-Gilmore, Igor Tolstoy, R. Reid Townsend, David D. Limbrick, Joseph N. Paulson, Jessica E. Ericson, Michael Y. Galperin, Steven J. Schiff, James R. Broach
Summary: Postinfectious hydrocephalus is associated with Paenibacillus thiaminolyticus infection. Comparative genomic and proteomic analysis identified potential virulence factors in the pathogenic strains. The findings provide insights into the diagnosis and treatment of Paenibacillus thiaminolyticus.
Article
Microbiology
Jean-Philippe Barnier, Daniel Euphrasie, Olivier Join-Lambert, Mathilde Audry, Sophia Schonherr-Hellec, Taliah Schmitt, Sandrine Bourdoulous, Mathieu Coureuil, Xavier Nassif, Mohamed El Behi
Summary: Neisseria meningitidis is a major cause of bacterial meningitis and fatal sepsis, as it can adhere to human endothelial cells and colonize microvessels using type IV pili (TFP). TFP dynamics, facilitated by PilT ATPase, play a crucial role in promoting sustained bacteremia and lethality in a humanized mouse model, highlighting the significance of pilus retraction in the pathogenesis and outcome of meningococcal sepsis.
Article
Microbiology
Ashok R. Nayak, Pradip K. Singh, Jinlei Zhao, Montserrat Samso, Michael S. Donnenberg
Summary: Type 4 pili are important surface appendages on bacteria and archaea that can extend and retract with great force. This study presents the detailed structure of an enzyme that converts chemical energy to mechanical energy in a human pathogen, revealing a mechanism of action not previously seen in enzymes that power type 4 pilus extension.
Article
Biochemistry & Molecular Biology
Kouhei Kishida, Rachel E. Bosserman, Laith Harb, Pratick Khara, Liqiang Song, Bo Hu, Lanying Zeng, Peter J. Christie
Summary: In this study, the authors used cryoET and fluorescence microscopy to investigate the structural transitions of T4SS(F)s during pilus production and the deposition of assembled pili onto alternative basal platforms. The deletion of F-specific genes from MOBF12C plasmid pED208 revealed three functional classes of F-specific subunits, which contribute to different steps of T4SS(F) assembly or activation. The findings suggest a new model in which F-specific subunits regulate DNA transfer and F pilus dynamics by interacting with distinct components of the T4SS(F).
MOLECULAR MICROBIOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Tiago R. D. Costa, Laith Harb, Pratick Khara, Lanying Zeng, Bo Hu, Peter J. Christie
Summary: Bacterial type IV secretion systems (T4SSs) are functionally diverse and consist of conjugation systems for DNA transfer and effector translocators for delivering macromolecules. These systems are defined by conserved core subunits and system-specific additional subunits, contributing to their functional versatility. Recent advances in defining T4SS assembly pathways and architectures are enhancing our understanding of substrate recruitment mechanisms and functional capabilities.
MOLECULAR MICROBIOLOGY
(2021)
Review
Microbiology
Courtney K. Ellison, Gregory B. Whitfield, Yves Brun
Summary: This review discusses recent progress in understanding the function, regulation, and mechanisms of T4P dynamics.
FEMS MICROBIOLOGY REVIEWS
(2022)
Review
Microbiology
Tiago R. D. Costa, Jonasz B. Patkowski, Kevin Mace, Peter J. Christie, Gabriel Waksman
Summary: Considerable progress has been made in recent years in understanding the structural and molecular biology of type IV secretion systems in Gram-negative bacteria. This knowledge is crucial for recognizing, recruiting, and transporting DNA and protein substrates. Further understanding of this secretion system will help combat antimicrobial resistance and treat type IV secretion system-related infections.
NATURE REVIEWS MICROBIOLOGY
(2023)
Article
Microbiology
Nancy Allard, Kevin Neil, Frederic Grenier, Sebastien Rodrigue
Summary: This study describes the type IV pilus (T4P) carried by TP114, a conjugative plasmid with high dissemination rates in the mouse intestinal tract. It is found that the minor pilin PilV acts as an adhesin that efficiently selects target cells for conjugative transfer, and the pilV gene can be rapidly modified by a shufflon, thus modulating the recipient bacteria during conjugation. The study highlights the role of mating pair stabilization in both broth and the gut microbiome, and provides insights into expanding the host spectrum of a plasmid by remodeling the PilV adhesin.
MICROBIOLOGY SPECTRUM
(2022)
Article
Microbiology
Evan Couser, Jennifer L. Chlebek, Ankur B. Dalia
Summary: Bacterial surface appendages called type IVa pili (T4aP) play important roles in various biological activities, and their dynamic extension and retraction rely on distinct ATPase motors. This study reveals that retraction ATPases are promiscuous and capable of promoting the retraction of a heterologous T4aP system, while extension ATPases are specific and cannot promote the extension of a heterologous T4aP.
JOURNAL OF BACTERIOLOGY
(2022)
Article
Multidisciplinary Sciences
Kevin Mace, Abhinav K. Vadakkepat, Adam Redzej, Natalya Lukoyanova, Clasien Oomen, Nathalie Braun, Marta Ukleja, Fang Lu, Tiago R. D. Costa, Elena Orlova, David Baker, Qian Cong, Gabriel Waksman
Summary: Bacterial conjugation is a crucial process for the transfer of DNA, especially antibiotic resistance genes. The high-resolution cryo-EM structure of the T4SS complex provides insights into the assembly mechanism and protein-protein interaction network involved in conjugative pilus biogenesis.
Article
Biophysics
Robert Zoellner, Tom Cronenberg, Nadzeya Kouzel, Anton Welker, Michael Koomey, Berenike Maier
BIOPHYSICAL JOURNAL
(2019)
Article
Microbiology
Robert Zoellner, Tom Cronenberg, Berenike Maier
JOURNAL OF BACTERIOLOGY
(2019)
Review
Microbiology
Lisa Craig, Katrina T. Forest, Berenike Maier
NATURE REVIEWS MICROBIOLOGY
(2019)
Article
Biochemistry & Molecular Biology
Marco Drexelius, Andre Reinhardt, Joshua Grabeck, Tom Cronenberg, Frank Nitsche, Pitter Huesgen, Berenike Maier, Ines Neundorf
Summary: The study identified novel AMPs with high activity by screening a synthetic library based on CPP sC18, which showed strong antibacterial activity and potential activity against cancer cells, while non-cancerous cells were not affected. These new candidates, especially those from generation 4, are seen as a valuable and promising source for the development of future therapeutics with antibacterial activity and beyond.
BIOCHEMICAL JOURNAL
(2021)
Review
Biophysics
Berenike Maier
Summary: Biofilms are structured communities formed by one or multiple microbial species, where bacteria adjust cell-to-cell interactions by tuning expression levels of surface and extracellular matrix components. Deciphering how gene expression changes affect physical interactions within biofilms is a key challenge, while bacteria control physical interactions to maximize their fitness is an emerging theme.
ANNUAL REVIEW OF BIOPHYSICS, VOL 50, 2021
(2021)
Article
Multidisciplinary Sciences
Jeffrey J. Power, Fernanda Pinheiro, Simone Pompei, Viera Kovacova, Melih Yueksel, Isabel Rathmann, Mona Foerster, Michael Laessig, Berenike Maier
Summary: Horizontal gene transfer is an important factor in bacterial evolution, allowing for rapid evolution and increased adaptation in recipient organisms. Adaptive evolution mainly occurs in populations with increased fitness, with HGT selection having a broad genetic basis and showing different types of selection in functional gene networks.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Microbiology
Tom Cronenberg, Marc Hennes, Isabelle Wielert, Berenike Maier
Summary: The research shows that antibiotics modulate T4P-mediated attractions and hence affect cell motility and colony fluidity. The study also reveals that survivability under ceftriaxone treatment depends on motility. Sequential treatment with azithromycin and ceftriaxone is found to be synergistic in enhancing bacterial survivability.
Article
Biophysics
Anton Welker, Marc Hennes, Niklas Bender, Tom Cronenberg, Gabriele Schneider, Berenike Maier
Summary: Bacterial growth within colonies and biofilms is heterogeneous, with the potential for steep gradients even in small colonies. Stringent response can slow down growth inhibition at the center of the colony. Aggregation-related growth inhibition can protect bacteria from external stresses in early biofilm stages.
BIOPHYSICAL JOURNAL
(2021)
Article
Microbiology
Sebastian Kraus-Roemer, Isabelle Wielert, Isabel Rathmann, Jan Grossbach, Berenike Maier
Summary: This study directly visualized the dynamics of gonococcal T4P and found that they are produced at a remarkably high rate in the absence of stress. Treatment with antibiotics or external stresses reduced T4P production. The findings suggest that the downregulation of T4P extrusion complexes and cellular energy depletion contribute to reduced piliation.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Ecology
Isabel Rathmann, Mona Foerster, Melih Yueksel, Lucas Horst, Gabriela Petrungaro, Tobias Bollenbach, Berenike Maier
Summary: Bacterial transformation, a common mechanism of horizontal gene transfer, can accelerate adaptive evolution. The study shows that transformation has greater fitness effects in complex medium and has the potential for rapid adaptive evolution. The distributions of fitness effects of transformation have a strong predictive value for determining the beneficial condition.
Article
Physics, Multidisciplinary
Kai Zhou, Marc Hennes, Berenike Maier, Gerhard Gompper, Benedikt Sabass
Summary: Adhesion forces due to active pili govern the formation of biofilms by bacteria. This study shows that active adhesions determine the morphology and non-equilibrium fluctuations of bacterial collectives, as well as their spreading dynamics in different geometries. The simulations also reveal the segregation of different types of cells in colonies depending on pili-mediated interactions. Furthermore, the study demonstrates that active force generation enables colonies to spread and invade narrow channels.
COMMUNICATIONS PHYSICS
(2022)
Article
Biochemistry & Molecular Biology
Marc Hennes, Niklas Bender, Tom Cronenberg, Anton Welker, Berenike Maier
Summary: Membrane potential in bacterial colonies of Neisseria gonorrhoeae transitions from uncorrelated to collective dynamics as the colonies reach a critical size. A hyperpolarized shell forms at the center and travels outward, followed by an influx of potassium correlated with depolarization. Oxygen gradients play a significant role in shaping the collective polarization dynamics and the hyperpolarized shell increases tolerance against aminoglycoside antibiotics, indicating distinct subpopulations within the colonies.
Article
Microbiology
Niklas Bender, Marc Hennes, Berenike Maier
Summary: Transformation allows bacteria to acquire genetic information from extracellular DNA. This study investigates DNA mobility within colonies formed by Neisseria gonorrhoeae and its relation to transformation efficiency. The presence of a DNA uptake sequence reduces DNA mobility, resulting in restricted mobility of gonococcal DNA. Despite rapid diffusion of DNA, transformation is limited to the edge of young colonies.
Article
Physics, Multidisciplinary
Marc Hennes, Tom Cronenberg, Berenike Maier
Summary: This study investigates the dynamics of bacterial cells in colonies, focusing on the effects of close packing on bacterial motility. The researchers found that at short timescales, bacterial motion is driven by type 4 pili interactions, transitioning to caged or diffusive dynamics at intermediate timescales. Long-term dynamics are dominated by growth-induced radial motion.
PHYSICAL REVIEW RESEARCH
(2022)
Review
Biochemistry & Molecular Biology
Berenike Maier
CURRENT ISSUES IN MOLECULAR BIOLOGY
(2020)
Article
Chemistry, Physical
Yiping Yin, Zhe Wang, Hua Zou
Summary: This study presents a novel method for preparing dimpled polymer-silica nanocomposite particles using interfacial swelling-based seeded polymerization. The optimized conditions allow for a relatively high percentage of dimpled particles to be achieved.
Article
Chemistry, Physical
Brenden D. Hoehn, Elizabeth A. Kellstedt, Marc A. Hillmyer
Summary: Porous materials with nanometer-scale pores have important applications as nanoporous membranes. In this study, ABA triblock copolymers were used as precursors to produce nanoporous polymeric membranes (NPMs) in thin film form by degrading the end blocks. Polycyclooctene (PCOE) NPMs with tunable pore sizes were successfully prepared using solvent casting technique. Oxygen plasma etching was employed to improve the surface porosity and hydrophilicity of the membranes. This study provides a straightforward method to produce tough NPMs with high porosity and hydrophilic surface properties.
Article
Chemistry, Physical
Vladislav S. Petrovskii, Stepan I. Zholudev, Igor I. Potemkin
Summary: This article investigates the behavior of linear and ring polypeptide chains in aqueous solution and explores the properties of the complexes formed by these chains with oppositely charged surfactants. The results demonstrate that the complexes of linear supercharged unfolded polypeptides and the corresponding surfactants exhibit impressive adhesive properties.
Article
Chemistry, Physical
Merve Cevik, Serkan Dikici
Summary: Cardiovascular diseases are a leading cause of death globally, and vascular grafts are a promising treatment option. This study focuses on tissue-engineered vascular grafts (TEVGs) using decellularized parsley stems as a potential biomaterial. The decellularized parsley stems showed suitable properties for TEVGs, providing a suitable environment for human endothelial cells to form a pseudo endothelium. This study showcases the potential of using parsley stems for TEVGs.
Article
Chemistry, Physical
Gustavo A. Vasquez-Montoya, Tadej Emersic, Noe Atzin, Antonio Tavera-Vazquez, Ali Mozaffari, Rui Zhang, Orlando Guzman, Alexey Snezhko, Paul F. Nealey, Juan J. de Pablo
Summary: The optical properties of liquid crystals are typically controlled by electric fields. In this study, we investigate the effects of microfluidic flows and acoustic fields on the molecular orientation and optical response of nematic liquid crystals. We identify several previously unknown structures and explain them through calculations and simulations. These findings hold promise for the development of new systems combining sound, flow, and confinement.
Article
Chemistry, Physical
Xinjun Wu, Xin Guan, Shushu Chen, Jiangpeng Jia, Chongyi Chen, Jiawei Zhang, Chuanzhuang Zhao
Summary: This research presents a novel shape memory hydrogel with a remodelable permanent shape and programmable cold-induced shape recovery behavior. The hydrogel is prepared using specific treatment methods to achieve shape fixation by heating and shape recovery by cooling. Additionally, deformable devices can be obtained by assembling hydrogel blocks with different concentrations.
Article
Chemistry, Physical
Rebecca Hengsbach, Gerhard Fink, Ulrich Simon
Summary: This study examines the properties of DNA functionalized pNipmam microgels and pure pNipmam microgels at different concentrations of sodium chloride and in PBS solutions using temperature dependent H-1-NMR measurements. The results show that DNA modification affects the volume phase transition temperature and the addition of salt and PBS further enhances this effect.
Article
Chemistry, Physical
Ningyi Li, Junhong Li, Lijingting Qing, Shicheng Ma, Yao Li, Baohui Li
Summary: This paper investigates the self-assembly behavior of colloids with competing interactions under spherical confinement and finds that different ordered structures can be formed under different sized spherical confinements. Moreover, more perforated structures are formed in smaller spheres.
