Raimo Hartmann

Max Planck Institute for Terrestrial Microbiology | MPITM · Biofilms

Bacteria can generate benefits for themselves and their kin by living in multicellular, matrix-enclosed communities, termed biofilms, which are fundamental to microbial ecology and the impact bacteria have on the environment, infections, and industry [1-6]. The advantages of the biofilm mode of life include increased stress resistance and access to...

In nature, bacteria primarily live in surface-attached, multicellular communities, termed biofilms. In medical settings, biofilms cause devastating damage during chronic and acute infections; indeed, bacteria are often viewed as agents of human disease. However, bacteria themselves suffer from diseases, most notably in the form of viral pathogens t...

Surface-attached bacterial biofilms are self-replicating active liquid crystals and the dominant form of bacterial life on Earth1,2,3,4. In conventional liquid crystals and solid-state materials, the interaction potentials between the molecules that comprise the system determine the material properties. However, for growth-active biofilms it is unc...

Biofilms are microbial communities that represent a highly abundant form of microbial life on Earth. Inside biofilms, phenotypic and genotypic variations occur in three-dimensional space and time; microscopy and quantitative image analysis are therefore crucial for elucidating their functions. Here, we present BiofilmQ—a comprehensive image cytomet...

Prokaryotic cells display striking subcellular organization. Studies of the underlying mechanisms in different species have greatly enhanced our understanding of the morphological and physiological adaptation of bacteria to different environmental niches. The image analysis software tool BacStalk is designed to extract comprehensive quantitative in...

Bacteria commonly live in spatially structured biofilm assemblages, which are encased by an extracellular matrix. Metabolic activity of the cells inside biofilms causes gradients in local environmental conditions, which leads to the emergence of physiologically differentiated subpopulations. Information about the properties and spatial arrangement...

The protein corona can significantly modulate the physicochemical properties and gene delivery of polyethylenimine (PEI)/DNA complexes (polyplexes). The effects of the protein corona on the transfection have been well studied in terms of averaged gene expression in a whole cell population. Such evaluation methods give excellent and reliable statist...

Three-dimensional fluorescence-based imaging of living cells and organisms requires the sample to be exposed to substantial excitation illumination energy, typically causing phototoxicity and photobleaching. Light sheet fluorescence microscopy dramatically reduces phototoxicity, yet most implementations are limited to objective lenses with low nume...

Bacteria commonly live in spatially structured assemblages encased by an extracellular matrix, termed biofilms. Metabolic activity of the cells inside biofilms causes gradients in local environmental conditions, which leads to the emergence of subpopulations with different metabolism. Basic information about the spatial arrangement of such metaboli...

A Correction to this paper has been published: https://doi.org/10.1038/s41564-021-00863-6.

Vibrio cholerae is the causative agent of the diarrheal disease cholera, for which biofilm communities are considered to be environmental reservoirs. In endemic regions, and after algal blooms, which may result from phosphate enrichment following agricultural runoff, the bacterium is released from bio-films resulting in seasonal disease outbreaks....

Biofilms are communities of bacteria protected by a self-produced extracellular matrix. The detrimental effects of nonproducing individuals on biofilm development raise questions about the dynamics between community members, especially when isogenic nonproducers exist within wild-type populations. We asked ourselves whether phenotypic nonproducers...

We have followed the segregation of origin regions on the Bacillus subtilis chromosome in the fastest practically achievable temporal manner, for a large fraction of the cell cycle. We show that segregation occurred in highly variable patterns but overall in an almost linear manner throughout the cell cycle. Segregation was slowed down, but not arr...

Vibrio cholerae remains a major global health threat, disproportionately impacting parts of the world without adequate infrastructure and sanitation resources. In aquatic environments, V. cholerae exists both as planktonic cells and as biofilms, which are held together by an extracellular matrix. V. cholerae biofilms have been shown to be hyperinfe...

Microorganisms have evolved specific cell surface molecules that enable discrimination between cells from the same and from a different kind. Here, we investigate the role of Flo11-type cell surface adhesins from social yeasts in kin discrimination. We measure the adhesion forces mediated by Flo11A-type domains using single-cell force spectroscopy,...

Bacterial biofilms represent a major form of microbial life on Earth and serve as a model active nematic system, in which activity results from growth of the rod-shaped bacterial cells. In their natural environments, ranging from human organs to industrial pipelines, biofilms have evolved to grow robustly under significant fluid shear. Despite inte...

Microbial populations form intricate macroscopic colonies with diverse morphologies whose functions remain to be fully understood. Despite fungal colonies isolated from environmental and clinical samples revealing abundant intraspecies morphological diversity, it is unclear how this diversity affects fungal fitness and disease progression. Here we...

Bacterial cells in nature are frequently exposed to changes in their chemical environment1,2. The response mechanisms of isolated cells to such stimuli have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure3,4,5,6,7, which may hold the key...

Biofilms form when bacteria aggregate in a self-secreted exopolysaccharide matrix. Biofilms are resistant to antibiotics and thus implicated in human disease. Nitric oxide (NO) is known to mediate biofilm formation in many bacteria via ligation to H-NOX (heme-NO/oxygen binding) proteins. Most NO-responsive bacteria, however, lack H-NOX domain-conta...

There is a large number of two‐dimensional static in vitro studies about the uptake of colloidal nano‐ and microparticles, which has been published in the last decade. In this Minireview, different methods used for such studies are summarized and critically discussed. Supplementary experimental data allow for a direct comparison of the different te...

The authors apologized for the unfortunate error in figure during publication of the article and they also explained that some of the solid grey graphs in Fig. 5 are intentionally based on the same data. For 8 different surface makers (CD14, CD73, CD34, CD105, CD19, CD90, CD45, HA-DR) in accordance to the guidelines of the manufacturer a panel of 4...

The self-produced biofilm provides beneficial protection for the enclosed cells, but the costly production of matrix components makes producer cells susceptible to cheating by non-producing individuals. Despite detrimental effects of non-producers, biofilms can be heterogeneous, with isogenic non-producers being a natural consequence of phenotypic...

Bacterial biofilms are matrix-bound multicellular communities. Biofilms represent a major form of microbial life on Earth and serve as a model active nematic system, in which activity results from growth of the rod-shaped bacterial cells. In their natural environments, from human organs to industrial pipelines, biofilms have evolved to grow robustl...

Significance Most living systems, from individual cells to tissues and swarms, display collective self-organization on length scales that are much larger than those of the individual units that drive this organization. A fundamental challenge is to understand how properties of microscopic components determine macroscopic, multicellular biological f...

Prokaryotes display a remarkable spatiotemporal organization of processes within individual cells. Investigations of the underlying mechanisms rely extensively on the analysis of microscopy images. Advanced image analysis software has revolutionized the cell-biological studies of established model organisms with largely symmetric rod-like cell shap...

Organisms as simple as bacteria can engage in complex collective actions, such as group motility and fruiting body formation. Some of these actions involve a division of labor, where phenotypically specialized clonal subpopulations or genetically distinct lineages cooperate with each other by performing complementary tasks. Here, we combine experim...

Given various cationic polymers developed as non-viral gene delivery vectors, polyethylenimine (PEI) has been/is frequently used in vitro transfection. However, the primary drawback limiting its in vivo applications is the sharp decrease in transfection efficiency in the presence of serum. Here, we investigated the influences of serum proteins or b...

List of parameters used in the model, including whether it represents an environmental factor (EF), a bacterial trait (BT) or an interaction between them. (DOCX)

Schematic of the experimental setup and the model updating rules. a) Experimental chamber, its tiles or viewing fields, and model representation of one of the tiles as a 2D lattice with one cell at each lattice box. b) Cell displacement due to shoving following cell division occurs with probability ps. With complementary probability 1-ps the reside...

Correlation length versus initial density. Mean correlation length, ξ, for different colonization strategies (σ, ρ0) in several ecological conditions given by the flow intensity f. Each curve represents a cell adhesiveness σ. The color code is maintained in all the panels. Averages are taken over 2x106 independent model realizations. (TIF)

Size effect analysis. Sensitivity analysis of the effect of system size in the simulations output. (DOCX)

Correlation length versus cell adhesiveness. Mean correlation length, ξ, for different colonization strategies (σ, ρ0) in several ecological conditions given by the flow intensity f. Each curve represents a value of the initial density, ρ0. The color code is maintained in all the panels. Averages are taken over 2x106 independent model realization....

Skewness of the correlation length. Skewness of the distribution of correlation lengths for different colonization strategies (σ, ρ0) and ecological conditions, given by the flow intensity f. Each curve represents a value of the adhesiveness σ, whose color code is maintained in all the panels. The skewness is obtained from 2x106 independent realiza...

Median correlation length. Median of the correlation length distribution for different colonization strategies (σ, ρ0) and ecological conditions given by the flow intensity f. Each curve represents a value of the adhesiveness σ. The color code is maintained in all the panels. The median is obtained from a set of 2x106 independent model realizations...

Cluster size variability. a) f = 0.25, b) f = 0.375, c) f = 0.5, d) f = 1. Each curve represents the standard deviation in ξ for a given adhesiveness, σ. Color code is maintained in all the panels. Averages are taken over 2x106 independent model realizations. (TIF)

Correlation function of individual model realizations. Correlation functions obtained for single realizations of the model at low (panel a; ρ0 = 10−3 cells/μm2) and high (panel b; ρ0 = 10−1 cells/μm2) initial density of cells. Correlation functions are obtained for the patterns shown in the snapshots. The color code indicates whether the pattern co...

Organisms as simple as bacteria can engage in complex collective actions, such as group motility and fruiting body formation. Some of these actions involve a division of labor, where phenotypically specialized clonal subpopulations, or genetically distinct lineages cooperate with each other by performing complementary tasks. Here, we combine experi...

Biofilms are microbial collectives that occupy a diverse array of surfaces. It is well known that the function and evolution of biofilms are strongly influenced by the spatial arrangement of different strains and species within them, but how spatiotemporal distributions of different genotypes in biofilm populations originate is still underexplored....

Biofilms are microbial collectives that occupy a diverse array of surfaces. The function and evolution of biofilms are strongly influenced by the spatial arrangement of different strains and species within them, but how spatiotemporal distributions of different genotypes in biofilm populations originate is still underexplored. Here, we study the or...

Movie S1. Biofilm Dispersal Is Triggered by Stopping the Flow through the Growth Channel, Related to Figure 1 and STAR Methods The movie shows two flow channels, one on the left, and one on the right, separated by a vertical white line. Vibrio cholerae wild-type biofilms (with a chromosomal GFP-expression system, strain KDV428, imaged by epifluore...

Movie S2. Spatiotemporal Organization of Biofilm Dispersal, Related to Figure 1 and STAR Methods Vibrio cholerae wild-type biofilms (carrying a GFP-expression plasmid, strain KDV296) were grown under constant flow (0.1 μL/min) for 20 h before dispersal was triggered by stopping the flow (see STAR Methods section “Dispersal experiments” for details...

Primary resistance to induction therapy is an unsolved clinical problem in acute myeloid leukemia (AML). Here we investigated drug resistance in AML at the level of cellular metabolism in order to identify early predictors of therapeutic response. Using extracellular flux analysis, we compared metabolic drug responses in AML cell lines sensitive or...

Biofilm formation is critical for the infection cycle of Vibrio cholerae. Vibrio exopolysaccharides (VPS) and the matrix proteins RbmA, Bap1 and RbmC are required for the development of biofilm architecture. We demonstrate that RbmA binds VPS directly and uses a binary structural switch within its first fibronectin type III (FnIII-1) domain to cont...

List of primers used in this study for generating various strains and plasmids.

The presence of a protein corona on various synthetic nanomaterials has been shown to strongly influence how they interact with cells. However, it is unclear if the protein corona also exists on protein particles, and if so, its role in particle-cell interactions. In this study, pure human serum albumin (HSA) particles were fabricated via mesoporou...

Background Mesenchymal stromal cells (MSCs) have an inherent migratory capacity towards tumor tissue in vivo. With the future objective to quantify the tumor homing efficacy of MSCs, as first step in this direction we investigated the use of inorganic nanoparticles (NPs), in particular ca. 4 nm-sized Au NPs, for MSC labeling. Time dependent uptake...

Understanding the mechanisms that are involved in determining bacterial growth rates is fundamental to infection biology, yet the factors that influence bacterial growth variation on surfaces are largely unknown. In this issue of ACS Nano, Lee et al. track individual bacteria on surfaces for several generations to discover systematic differences in...

We have studied the effect of the zwitterionic surface coating of quantum dots (QDs) on their interaction with a serum supplemented cell medium and their internalization by human cervical carcinoma (HeLa) cells. Zwitterionic QDs showed negligible adsorption of human serum albumin (HSA) selected as a model serum protein, in contrast to similar but n...

Many bacteria primarily exist in nature as structured multicellular communities, so called biofilms. Biofilm formation is a highly regulated process that includes the transition from the motile planktonic to sessile biofilm lifestyle. Cellular differentiation within a biofilm is a commonly accepted concept but it remains largely unclear when, where...

Due to their small size and related interesting properties, artificial nanomaterials are utilized for a great number of biological and medical applications. Cell entry routes, intracellular trafficking and processing of nanoparticles, which determine their fate, efficiency, and toxicity, are depending on various parameters of the specific nanomater...

Near-ultraviolet and visible excitable Eu- and Bi-doped NPs based on rare earth vanadates (REVO4, RE = Y, Gd) have been synthesized by a facile route from appropriate RE precursors, europium and bismuth nitrate, and sodium orthovanadate, by homogeneous precipitation in an ethylene glycol/water mixture at 120 °C. The NPs can be functionalized either...