Correction: Shaping the Growth Behaviour of Biofilms Initiated from Bacterial Aggregates.
Ontology highlight
ABSTRACT:
SUBMITTER: PLOS ONE Staff
PROVIDER: S-EPMC4847861 | biostudies-literature | 2016
REPOSITORIES: biostudies-literature
Publications
Correction: Shaping the Growth Behaviour of Biofilms Initiated from Bacterial Aggregates.
PloS one 20160427 4
[This corrects the article DOI: 10.1371/journal.pone.0149683.]. ...[more]
Similar Datasets
Project description:Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase so that it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the initial shape the aggregate forms on the surface, we find that the degree of spreading of an aggregate on a surface can play an important role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding unaggregated bacterial cells is low, while initially rounded aggregates perform better when competition with surrounding unaggregated cells is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the social evolution of biofilm communities.
| S-EPMC4774936 | biostudies-literature
Project description:In response to environmental stresses such as starvation, many bacteria facultatively aggregate into multicellular structures that can attain new metabolic functions and behaviors. Despite the ubiquity and relevance of this form of collective behavior, we lack an understanding of how the spatiotemporal dynamics of aggregate development emerge from cellular physiology. Here, we study the development of multicellular aggregates by the marine bacterium Vibrio splendidus when it grows on the polysaccharide alginate. Transcriptional profiling was used to define genes differentially expressed at stages of aggregate morphogenesis, and between cell sub-populations, which included genes encoding a putative type IV pillus and carbon storage granules. Combined with measurements of in situ cellular physiology, we show that the coupling between growth and spatial gradient formation leads to the emergence of a complex lifecycle.
2021-12-10 | GSE190325 | GEO
Project description:In microbial communities such as those found in biofilms, individual organisms most often display heterogeneous behavior with respect to their metabolic activity, growth status, gene expression pattern, etc. In that context, a novel reporter system for monitoring of cellular growth activity has been designed. It comprises a transposon cassette carrying fusions between the growth rate-regulated Escherichia coli rrnBP1 promoter and different variant gfp genes. It is shown that the P1 promoter is regulated in the same way in E. coli and Pseudomonas putida, making it useful for monitoring of growth activity in organisms outside the group of enteric bacteria. Construction of fusions to genes encoding unstable Gfp proteins opened up the possibility of the monitoring of rates of rRNA synthesis and, in this way, allowing on-line determination of the distribution of growth activity in a complex community. With the use of these reporter tools, it is demonstrated that individual cells of a toluene-degrading P. putida strain growing in a benzyl alcohol-supplemented biofilm have different levels of growth activity which develop as the biofilm gets older. Cells that eventually grow very slowly or not at all may be stimulated to restart growth if provided with a more easily metabolizable carbon source. Thus, the dynamics of biofilm growth activity has been tracked to the level of individual cells, cell clusters, and microcolonies.
| S-EPMC99748 | biostudies-literature
Project description:Biofilms are complex communities of microbes that attach to biotic or abiotic surfaces causing chronic infectious diseases. Within a biofilm, microbes are embedded in a self-produced soft extracellular matrix (ECM), which protects them from the host immune system and antibiotics. The nanoscale visualisation of delicate biofilms in liquid is challenging. Here, we develop atmospheric scanning electron microscopy (ASEM) to visualise Gram-positive and -negative bacterial biofilms immersed in aqueous solution. Biofilms cultured on electron-transparent film were directly imaged from below using the inverted SEM, allowing the formation of the region near the substrate to be studied at high resolution. We visualised intercellular nanostructures and the exocytosis of membrane vesicles, and linked the latter to the trafficking of cargos, including cytoplasmic proteins and the toxins hemolysin and coagulase. A thick dendritic nanotube network was observed between microbes, suggesting multicellular communication in biofilms. A universal immuno-labelling system was developed for biofilms and tested on various examples, including S. aureus biofilms. In the ECM, fine DNA and protein networks were visualised and the precise distribution of protein complexes was determined (e.g., straight curli, flagella, and excreted cytoplasmic molecular chaperones). Our observations provide structural insights into bacteria-substratum interactions, biofilm development and the internal microbe community.
| S-EPMC4867632 | biostudies-literature
Project description:BackgroundAggregation of the ?-Synuclein (?-Syn) protein, amyloid fibril formation and progressive neurodegeneration are the neuropathological hallmarks of Parkinson's Disease (PD). However, a detailed mechanism of ?-Syn aggregation/fibrillogenesis and the exact nature of toxic oligomeric species produced during amyloid formation process are still unknown.ResultsIn this study, the rates of ?-Syn aggregation were compared for the recombinant wild-type (WT) ?-Syn and a structurally relevant chimeric homologous protein containing an inducible Fv dimerizing domain (?-SynFv), capable to form dimers in the presence of a divalent ligand (AP20187). In the presence of AP20187, we report a rapid random coil into ?-sheet conformational transformation of ?-SynFv within 24 h, whereas WT ?-Syn showed 24 h delay to achieve ?-sheet structure after 48 h. Fluorescence ANS and ThT binding experiments demonstrate an accelerated oligomer/amyloid formation of dimerized ?-SynFv, compared to the slower oligomerization and amyloidogenesis of WT ?-Syn or ?-SynFv without dimerizer AP20187. Both ?-SynFv and ?-Syn pre-fibrillar aggregates internalized cells and induced neurotoxicity when injected into the hippocampus of wild-type mice. These recombinant toxic aggregates further converted into non-toxic amyloids which were successfully amplified by protein misfolding cyclic amplification method, providing the first evidence for the in vitro propagation of synthetic ?-Syn aggregates.ConclusionsTogether, we show that dimerization is important for ?-Syn conformational transition and aggregation. In addition, ?-Syn dimerization can accelerate the formation of neurotoxic aggregates and amyloid fibrils which can be amplified in vitro. A detailed characterization of the mechanism of ?-Syn aggregation/amyloidogenesis and toxicity is crucial to comprehend Parkinson's disease pathology at the molecular level.
| S-EPMC3764494 | biostudies-literature
Project description:Oligosaccharides produced from the extracellular hydrolysis of biological materials can act as common goods that promote cooperative growth in microbial populations, whereby cell-cell aggregation increases both the per capita availability of resources and the per-cell growth rate. However, aggregation can also have detrimental consequences for growth, as gradients form within aggregates limiting the resource accessibility. We built a computational model, which predicts cooperation is restricted in dense cell aggregates larger than 10 µm because of the emergence of polymer and oligomer counter gradients. We compared these predictions to experiments performed with two well-studied alginate-degrading strains of Vibrio splendidus, which varied in their ability to secrete alginate lyase. We observed that both strains can form large aggregates (less than 50 µm), overcoming diffusion limitation by rearranging their internal structure. The stronger enzyme producer grew non-cooperatively and formed aggregates with internal channels that allowed exchange between the bulk environment and the aggregate, whereas the weak enzyme producer showed strongly cooperative growth and formed dense aggregates in which cells near the core mixed by active swimming. Our simulations suggest that the mixing and channelling reduce diffusion limitation and allow cells to uniformly grow in aggregates. Together, these data demonstrate that bacterial behaviour can help overcome competition imposed by resource gradients within cell aggregates. This article is part of a discussion meeting issue 'Single cell ecology'.
| S-EPMC6792450 | biostudies-literature
Project description:Biofilms are communities of bacteria adhered to surfaces. Recently, biofilms of rod-shaped bacteria were observed at single-cell resolution and shown to develop from a disordered, two-dimensional layer of founder cells into a three-dimensional structure with a vertically-aligned core. Here, we elucidate the physical mechanism underpinning this transition using a combination of agent-based and continuum modeling. We find that verticalization proceeds through a series of localized mechanical instabilities on the cellular scale. For short cells, these instabilities are primarily triggered by cell division, whereas long cells are more likely to be peeled off the surface by nearby vertical cells, creating an "inverse domino effect". The interplay between cell growth and cell verticalization gives rise to an exotic mechanical state in which the effective surface pressure becomes constant throughout the growing core of the biofilm surface layer. This dynamical isobaricity determines the expansion speed of a biofilm cluster and thereby governs how cells access the third dimension. In particular, theory predicts that a longer average cell length yields more rapidly expanding, flatter biofilms. We experimentally show that such changes in biofilm development occur by exploiting chemicals that modulate cell length.
| S-EPMC6426328 | biostudies-literature
Project description:Biofilms develop from bacteria bound on surfaces that grow into structured communities (microcolonies). Although surface topography is known to affect bacterial colonization, how multiple individual settlers develop into microcolonies simultaneously remains underexplored. Here, we use multiscale population-growth and 3D-morphometric analyses to assess the spatiotemporal development of hundreds of bacterial colonizers towards submillimeter-scale microcolony communities. Using an oral bacterium (Streptococcus mutans), we find that microbial cells settle on the surface randomly under sucrose-rich conditions, regardless of surface topography. However, only a subset of colonizers display clustering behavior and growth following a power law. These active colonizers expand three-dimensionally by amalgamating neighboring bacteria into densely populated microcolonies. Clustering and microcolony assembly are dependent on exopolysaccharides, while population growth dynamics and spatial structure are affected by cooperative or antagonistic microbes. Our work suggests that biofilm assembly resembles certain spatial-structural features of urbanization, where population growth and expansion can be influenced by type of settlers, neighboring cells, and further community merging and scaffolding occurring at various scales.
| S-EPMC7070081 | biostudies-literature
Project description:In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we investigated electrical signalling as a possible driver in biofilm sociobiology. Using a multi-electrode array system that enables high spatio-temporal resolution, we studied the electrical activity in two biofilm-forming strains and one non-biofilm-forming strain. The action potential rates monitored during biofilm-forming bacterial growth exhibited a one-peak maximum with a long tail, corresponding to the highest biofilm development. This peak was not observed for the non-biofilm-forming strain, demonstrating that the intensity of the electrical activity was not linearly related to the bacterial density, but was instead correlated with biofilm formation. Results obtained indicate that the analysis of the spatio-temporal electrical activity of bacteria during biofilm formation can open a new frontier in the study of the emergence of collective microbial behaviour.
| S-EPMC4277093 | biostudies-literature
Project description:The spatial organization of gut microbiota influences both microbial abundances and host-microbe interactions, but the underlying rules relating bacterial dynamics to large-scale structure remain unclear. To this end, we studied experimentally and theoretically the formation of three-dimensional bacterial clusters, a key parameter controlling susceptibility to intestinal transport and access to the epithelium. Inspired by models of structure formation in soft materials, we sought to understand how the distribution of gut bacterial cluster sizes emerges from bacterial-scale kinetics. Analyzing imaging-derived data on cluster sizes for eight different bacterial strains in the larval zebrafish gut, we find a common family of size distributions that decay approximately as power laws with exponents close to -2, becoming shallower for large clusters in a strain-dependent manner. We show that this type of distribution arises naturally from a Yule-Simons-type process in which bacteria grow within clusters and can escape from them, coupled to an aggregation process that tends to condense the system toward a single massive cluster, reminiscent of gel formation. Together, these results point to the existence of general, biophysical principles governing the spatial organization of the gut microbiome that may be useful for inferring fast-timescale dynamics that are experimentally inaccessible.
| S-EPMC8514234 | biostudies-literature