1
|
Pessione E. The Less Expensive Choice: Bacterial Strategies to Achieve Successful and Sustainable Reciprocal Interactions. Front Microbiol 2021; 11:571417. [PMID: 33584557 PMCID: PMC7873842 DOI: 10.3389/fmicb.2020.571417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 12/11/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria, the first organisms that appeared on Earth, continue to play a central role in ensuring life on the planet, both as biogeochemical agents and as higher organisms' symbionts. In the last decades, they have been employed both as bioremediation agents for cleaning polluted sites and as bioconversion effectors for obtaining a variety of products from wastes (including eco-friendly plastics and green energies). However, some recent reports suggest that bacterial biodiversity can be negatively affected by the present environmental crisis (global warming, soil desertification, and ocean acidification). This review analyzes the behaviors positively selected by evolution that render bacteria good models of sustainable practices (urgent in these times of climate change and scarcity of resources). Actually, bacteria display a tendency to optimize rather than maximize, to economize energy and building blocks (by using the same molecule for performing multiple functions), and to recycle and share metabolites, and these are winning strategies when dealing with sustainability. Furthermore, their ability to establish successful reciprocal relationships by means of anticipation, collective actions, and cooperation can also constitute an example highlighting how evolutionary selection favors behaviors that can be strategic to contain the present environmental crisis.
Collapse
Affiliation(s)
- Enrica Pessione
- Department of Life Sciences and Systems Biology, Università degli Studi di Torino, Torino, Italy
| |
Collapse
|
2
|
Li Y, Jian X, Li Y, Zeng X, Xu L, Khan MU, Lin W. OsPAL2-1 Mediates Allelopathic Interactions Between Rice and Specific Microorganisms in the Rhizosphere Ecosystem. Front Microbiol 2020; 11:1411. [PMID: 32793125 PMCID: PMC7391800 DOI: 10.3389/fmicb.2020.01411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 05/29/2020] [Indexed: 11/13/2022] Open
Abstract
The use of plant allelopathy to control weeds in the field has been generally recognized as a win-win strategy because it is an environmentally friendly and resource-saving method. The mechanism of this natural weed-control method relies on allelochemicals, the rhizosphere microbiome, and their bio-interaction, and exploring the link between allelochemicals and specific microbes helps accelerate the application of allelopathic characteristics in farming. In this study, we used allelopathic rice PI312777 (PI), its genetically modified OsPAL2-1 repression (PR) or overexpression (PO) lines, and non-allelopathic rice Lemont (Le) as donor plants to reveal the bio-interaction between rice allelochemicals and rhizosphere specific microorganisms. The results showed a higher content of phenolic acid exudation from the roots of PI than those of Le, which resulted in a significantly increased population of Myxococcus in the rhizosphere soil. Transgenic PO lines exhibited increasing exudation of phenolic acid, which led to the population of Myxococcus xanthus in the rhizosphere soil of PO to be significantly increased, while PR showed the opposite result in comparison with wild type PI. Exogenous application of phenolic acid induced the growth of M. xanthus, and the expressions of chemotaxis-related genes were up-regulated in M. xanthus. In addition, quercetin was identified in the culture medium; according to the bioassay determination, a quercetin concentration of 0.53 mM inhibited the root length by 60.59%. Our study indicates that OsPAL2-1 is among the efficient genes that regulate rice allelopathy by controlling the synthesis of phenolic acid allelochemicals, and phenolic acid (ferulic acid, FA) induces the chemotactic aggregation of M. xanthus, which promoted the proliferation and aggregation of this microbe. The potential allelochemical, quercetin was generated from the FA-induced M. xanthus cultured medium.
Collapse
Affiliation(s)
- Yingzhe Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Xin Jian
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Yue Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Xiaomei Zeng
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Lining Xu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Muhammad Umar Khan
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China
| | - Wenxiong Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| |
Collapse
|
3
|
|
4
|
Herrou J, Mignot T. Dynamic polarity control by a tunable protein oscillator in bacteria. Curr Opin Cell Biol 2019; 62:54-60. [PMID: 31627169 DOI: 10.1016/j.ceb.2019.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/09/2019] [Accepted: 09/05/2019] [Indexed: 01/30/2023]
Abstract
In bacteria, cell polarization involves the controlled targeting of specific proteins to the poles, defining polar identity and function. How a specific protein is targeted to one pole and what are the processes that facilitate its dynamic relocalization to the opposite pole is still unclear. The Myxococcus xanthus polarization example illustrates how the dynamic and asymmetric localization of polar proteins enable a controlled and fast switch of polarity. In M. xanthus, the opposing polar distribution of the small GTPase MglA and its cognate activating protein MglB defines the direction of movement of the cell. During a reversal event, the switch of direction is triggered by the Frz chemosensory system, which controls polarity reversals through a so-called gated relaxation oscillator. In this review, we discuss how this genetic architecture can provoke sharp behavioral transitions depending on Frz activation levels, which is central to multicellular behaviors in this bacterium.
Collapse
Affiliation(s)
- Julien Herrou
- Laboratoire de Chimie Bactérienne, CNRS - Aix Marseille University UMR 7283, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, CNRS - Aix Marseille University UMR 7283, Institut de Microbiologie de la Méditerranée, Marseille, France.
| |
Collapse
|
5
|
Burgard C, Zaburannyi N, Nadmid S, Maier J, Jenke-Kodama H, Luxenburger E, Bernauer HS, Wenzel SC. Genomics-Guided Exploitation of Lipopeptide Diversity in Myxobacteria. ACS Chem Biol 2017; 12:779-786. [PMID: 28128551 DOI: 10.1021/acschembio.6b00953] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Analysis of 122 myxobacterial genome sequences suggested 16 strains as producers of the myxochromide lipopeptide family. Detailed sequence comparison of the respective mch biosynthetic gene clusters informed a genome-mining approach, ultimately leading to the discovery and chemical characterization of four novel myxochromide core types. The myxochromide megasynthetase is subject to evolutionary diversification, resulting in considerable structural diversity of biosynthesis products. The observed differences are due to the number, type, sequence, and configuration of the incorporated amino acids. The analysis revealed molecular details on how point mutations and recombination events led to structural diversity. It also gave insights into the evolutionary scenarios that have led to the emergence of mch clusters in different strains and genera of myxobacteria.
Collapse
Affiliation(s)
- Christian Burgard
- Helmholtz
Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre
for Infection Research and Pharmaceutical Biotechnology at Saarland
University, Saarland University Campus, Building E8.1, 66123 Saarbrücken, Germany
| | - Nestor Zaburannyi
- Helmholtz
Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre
for Infection Research and Pharmaceutical Biotechnology at Saarland
University, Saarland University Campus, Building E8.1, 66123 Saarbrücken, Germany
| | - Suvd Nadmid
- Helmholtz
Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre
for Infection Research and Pharmaceutical Biotechnology at Saarland
University, Saarland University Campus, Building E8.1, 66123 Saarbrücken, Germany
| | - Josef Maier
- IStLS − Information Services to Life Sciences, Härlestraße 24/1, 78727 Oberndorf am Neckar/Boll, Germany
| | - Holger Jenke-Kodama
- Microbiology
and Biochemistry of Secondary Metabolites Unit, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Eva Luxenburger
- Helmholtz
Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre
for Infection Research and Pharmaceutical Biotechnology at Saarland
University, Saarland University Campus, Building E8.1, 66123 Saarbrücken, Germany
| | | | - Silke C. Wenzel
- Helmholtz
Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre
for Infection Research and Pharmaceutical Biotechnology at Saarland
University, Saarland University Campus, Building E8.1, 66123 Saarbrücken, Germany
| |
Collapse
|
6
|
Mercier R, Mignot T. Regulations governing the multicellular lifestyle of Myxococcus xanthus. Curr Opin Microbiol 2016; 34:104-110. [PMID: 27648756 DOI: 10.1016/j.mib.2016.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
In living organisms, cooperative cell movements underlie the formation of differentiated tissues. In bacteria, Myxococcus xanthus uses cooperative group movements, to predate on prey and to form multicellular fruiting bodies, where the cells differentiate into dormant spores. Motility is controlled by a central signaling Che-like pathway, Frz. Single cell studies indicate Frz regulates the frequency at which cells reverse their direction of movement by transmitting signals to a molecular system that controls the spatial activity of the motility engines. This regulation is central to all Myxococcus multicellular behaviors but how Frz signaling generates ordered patterns is poorly understood. In this review, we first discuss the genetic structure of the Frz pathway and possible regulations that could explain its action during Myxococcus development.
Collapse
Affiliation(s)
- Romain Mercier
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| |
Collapse
|
7
|
Patra P, Kissoon K, Cornejo I, Kaplan HB, Igoshin OA. Colony Expansion of Socially Motile Myxococcus xanthus Cells Is Driven by Growth, Motility, and Exopolysaccharide Production. PLoS Comput Biol 2016; 12:e1005010. [PMID: 27362260 PMCID: PMC4928896 DOI: 10.1371/journal.pcbi.1005010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/02/2016] [Indexed: 12/21/2022] Open
Abstract
Myxococcus xanthus, a model organism for studies of multicellular behavior in bacteria, moves exclusively on solid surfaces using two distinct but coordinated motility mechanisms. One of these, social (S) motility is powered by the extension and retraction of type IV pili and requires the presence of exopolysaccharides (EPS) produced by neighboring cells. As a result, S motility requires close cell-to-cell proximity and isolated cells do not translocate. Previous studies measuring S motility by observing the colony expansion of cells deposited on agar have shown that the expansion rate increases with initial cell density, but the biophysical mechanisms involved remain largely unknown. To understand the dynamics of S motility-driven colony expansion, we developed a reaction-diffusion model describing the effects of cell density, EPS deposition and nutrient exposure on the expansion rate. Our results show that at steady state the population expands as a traveling wave with a speed determined by the interplay of cell motility and growth, a well-known characteristic of Fisher’s equation. The model explains the density-dependence of the colony expansion by demonstrating the presence of a lag phase–a transient period of very slow expansion with a duration dependent on the initial cell density. We propose that at a low initial density, more time is required for the cells to accumulate enough EPS to activate S-motility resulting in a longer lag period. Furthermore, our model makes the novel prediction that following the lag phase the population expands at a constant rate independent of the cell density. These predictions were confirmed by S motility experiments capturing long-term expansion dynamics. Collective motility is a key mechanism bacteria use to self-organize into multicellular structures and to adapt to various environments. An important example of such behavior is social (S) motility in the gram-negative bacterium Myxococcus xanthus. S-motile cells are restricted to movement in groups and do not move as individual cells. S-motility is powered by type IV pili (TFP)–multi-subunit filaments, which extrude from the cell poles, adhere to the substrate and retract, pulling the cell forward. TFP retraction or adhesion is suggested to be triggered by extracellular exopolysaccharides (EPS) deposited by cells on the substrate. As individual cells synthesize both pili and EPS, it is unclear why S-motile cells only exhibit group movement. Moreover, the experimentally observed initial cell-density dependence of S-motility remains unexplained. To understand these phenomena, we developed a mathematical model for the colony expansion of S-motile cells. Our model hypothesizes that the EPS level regulates the TFP activity that initiates collective cell movements. With this assumption, the model quantitatively matches the density-dependent expansion rate. Moreover, the model predicts two phases during colony expansion: an initial density-dependent lag phase with a slow expansion rate, followed by a faster expansion phase with a density-independent rate. These model predictions were confirmed by long-term colony expansion experiments.
Collapse
Affiliation(s)
- Pintu Patra
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
| | - Kimberley Kissoon
- Department of Natural Sciences, Del Mar College, Corpus Christi, Texas, United States of America
| | - Isabel Cornejo
- Department of Natural Sciences, University of Houston-Downtown, Houston, Texas, United States of America
| | - Heidi B. Kaplan
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas, United States of America
| | - Oleg A. Igoshin
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
- * E-mail:
| |
Collapse
|
8
|
Muñoz-Dorado J, Marcos-Torres FJ, García-Bravo E, Moraleda-Muñoz A, Pérez J. Myxobacteria: Moving, Killing, Feeding, and Surviving Together. Front Microbiol 2016; 7:781. [PMID: 27303375 PMCID: PMC4880591 DOI: 10.3389/fmicb.2016.00781] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/09/2016] [Indexed: 11/13/2022] Open
Abstract
Myxococcus xanthus, like other myxobacteria, is a social bacterium that moves and feeds cooperatively in predatory groups. On surfaces, rod-shaped vegetative cells move in search of the prey in a coordinated manner, forming dynamic multicellular groups referred to as swarms. Within the swarms, cells interact with one another and use two separate locomotion systems. Adventurous motility, which drives the movement of individual cells, is associated with the secretion of slime that forms trails at the leading edge of the swarms. It has been proposed that cellular traffic along these trails contributes to M. xanthus social behavior via stigmergic regulation. However, most of the cells travel in groups by using social motility, which is cell contact-dependent and requires a large number of individuals. Exopolysaccharides and the retraction of type IV pili at alternate poles of the cells are the engines associated with social motility. When the swarms encounter prey, the population of M. xanthus lyses and takes up nutrients from nearby cells. This cooperative and highly density-dependent feeding behavior has the advantage that the pool of hydrolytic enzymes and other secondary metabolites secreted by the entire group is shared by the community to optimize the use of the degradation products. This multicellular behavior is especially observed in the absence of nutrients. In this condition, M. xanthus swarms have the ability to organize the gliding movements of 1000s of rods, synchronizing rippling waves of oscillating cells, to form macroscopic fruiting bodies, with three subpopulations of cells showing division of labor. A small fraction of cells either develop into resistant myxospores or remain as peripheral rods, while the majority of cells die, probably to provide nutrients to allow aggregation and spore differentiation. Sporulation within multicellular fruiting bodies has the benefit of enabling survival in hostile environments, and increases germination and growth rates when cells encounter favorable conditions. Herein, we review how these social bacteria cooperate and review the main cell–cell signaling systems used for communication to maintain multicellularity.
Collapse
Affiliation(s)
- José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada Granada, Spain
| | | | - Elena García-Bravo
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada Granada, Spain
| | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada Granada, Spain
| | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada Granada, Spain
| |
Collapse
|
9
|
Bonilla LL, Glavan A, Marquina A. Wavelength selection of rippling patterns in myxobacteria. Phys Rev E 2016; 93:012412. [PMID: 26871106 DOI: 10.1103/physreve.93.012412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Indexed: 11/07/2022]
Abstract
Rippling patterns of myxobacteria appear in starving colonies before they aggregate to form fruiting bodies. These periodic traveling cell density waves arise from the coordination of individual cell reversals, resulting from an internal clock regulating them and from contact signaling during bacterial collisions. Here we revisit a mathematical model of rippling in myxobacteria due to Igoshin et al. [Proc. Natl. Acad. Sci. USA 98, 14913 (2001)PNASA60027-842410.1073/pnas.221579598 and Phys. Rev. E 70, 041911 (2004)PLEEE81539-375510.1103/PhysRevE.70.041911]. Bacteria in this model are phase oscillators with an extra internal phase through which they are coupled to a mean field of oppositely moving bacteria. Previously, patterns for this model were obtained only by numerical methods, and it was not possible to find their wave number analytically. We derive an evolution equation for the reversal point density that selects the pattern wave number in the weak signaling limit, shows the validity of the selection rule by solving numerically the model equations, and describes other stable patterns in the strong signaling limit. The nonlocal mean-field coupling tends to decohere and confine patterns. Under appropriate circumstances, it can annihilate the patterns leaving a constant density state via a nonequilibrium phase transition reminiscent of destruction of synchronization in the Kuramoto model.
Collapse
Affiliation(s)
- L L Bonilla
- G. Millán Institute, Fluid Dynamics, Nanoscience and Industrial Mathematics, Universidad Carlos III de Madrid, Avda. Universidad 30; E-28911 Leganés, Spain
| | - A Glavan
- G. Millán Institute, Fluid Dynamics, Nanoscience and Industrial Mathematics, Universidad Carlos III de Madrid, Avda. Universidad 30; E-28911 Leganés, Spain
| | - A Marquina
- Departmento de Matemática Aplicada, Universidad de Valencia, Avda. Dr. Moliner 50; E-46100 Burjassot-Valencia, Spain
| |
Collapse
|
10
|
How Myxobacteria Cooperate. J Mol Biol 2015; 427:3709-21. [PMID: 26254571 DOI: 10.1016/j.jmb.2015.07.022] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 11/22/2022]
Abstract
Prokaryotes often reside in groups where a high degree of relatedness has allowed the evolution of cooperative behaviors. However, very few bacteria or archaea have made the successful transition from unicellular to obligate multicellular life. A notable exception is the myxobacteria, in which cells cooperate to perform group functions highlighted by fruiting body development, an obligate multicellular function. Like all multicellular organisms, myxobacteria face challenges in how to organize and maintain multicellularity. These challenges include maintaining population homeostasis, carrying out tissue repair and regulating the behavior of non-cooperators. Here, we describe the major cooperative behaviors that myxobacteria use: motility, predation and development. In addition, this review emphasizes recent discoveries in the social behavior of outer membrane exchange, wherein kin share outer membrane contents. Finally, we review evidence that outer membrane exchange may be involved in regulating population homeostasis, thus serving as a social tool for myxobacteria to make the cyclic transitions from unicellular to multicellular states.
Collapse
|
11
|
Lyon P. The cognitive cell: bacterial behavior reconsidered. Front Microbiol 2015; 6:264. [PMID: 25926819 PMCID: PMC4396460 DOI: 10.3389/fmicb.2015.00264] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 03/16/2015] [Indexed: 01/28/2023] Open
Abstract
Research on how bacteria adapt to changing environments underlies the contemporary biological understanding of signal transduction (ST), and ST provides the foundation of the information-processing approach that is the hallmark of the ‘cognitive revolution,’ which began in the mid-20th century. Yet cognitive scientists largely remain oblivious to research into microbial behavior that might provide insights into problems in their own domains, while microbiologists seem equally unaware of the potential importance of their work to understanding cognitive capacities in multicellular organisms, including vertebrates. Evidence in bacteria for capacities encompassed by the concept of cognition is reviewed. Parallels exist not only at the heuristic level of functional analogue, but also at the level of molecular mechanism, evolution and ecology, which is where fruitful cross-fertilization among disciplines might be found.
Collapse
Affiliation(s)
- Pamela Lyon
- Southgate Institute for Health, Society and Equity, School of Medicine, Flinders University Adelaide, SA, Australia
| |
Collapse
|
12
|
Cell division resets polarity and motility for the bacterium Myxococcus xanthus. J Bacteriol 2014; 196:3853-61. [PMID: 25157084 DOI: 10.1128/jb.02095-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Links between cell division and other cellular processes are poorly understood. It is difficult to simultaneously examine division and function in most cell types. Most of the research probing aspects of cell division has experimented with stationary or immobilized cells or distinctly asymmetrical cells. Here we took an alternative approach by examining cell division events within motile groups of cells growing on solid medium by time-lapse microscopy. A total of 558 cell divisions were identified among approximately 12,000 cells. We found an interconnection of division, motility, and polarity in the bacterium Myxococcus xanthus. For every division event, motile cells stop moving to divide. Progeny cells of binary fission subsequently move in opposing directions. This behavior involves M. xanthus Frz proteins that regulate M. xanthus motility reversals but is independent of type IV pilus "S motility." The inheritance of opposing polarity is correlated with the distribution of the G protein RomR within these dividing cells. The constriction at the point of division limits the intracellular distribution of RomR. Thus, the asymmetric distribution of RomR at the parent cell poles becomes mirrored at new poles initiated at the site of division.
Collapse
|
13
|
Transmission of a signal that synchronizes cell movements in swarms of Myxococcus xanthus. Proc Natl Acad Sci U S A 2014; 111:13105-10. [PMID: 25149859 DOI: 10.1073/pnas.1411925111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We offer evidence for a signal that synchronizes the behavior of hundreds of Myxococcus xanthus cells in a growing swarm. Swarms are driven to expand by the periodic reversing of direction by members. By using time-lapse photomicroscopy, two organized multicellular elements of the swarm were analyzed: single-layered, rectangular rafts and round, multilayered mounds. Rafts of hundreds of cells with their long axes aligned in parallel enlarge as individual cells from the neighborhood join them from either side. Rafts can also add a second layer piece by piece. By repeating layer additions to a raft and rounding each layer, a regular multilayered mound can be formed. About an hour after a five-layered mound had formed, all of the cells from its top layer descended to the periphery of the fourth layer, both rapidly and synchronously. Following the first synchronized descent and spaced at constant time intervals, a new fifth layer was (re)constructed from fourth-layer cells, in very close proximity to its old position and with a number of cells similar to that before the "explosive" descent. This unexpected series of changes in mound structure can be explained by the spread of a signal that synchronizes the reversals of large groups of individual cells.
Collapse
|
14
|
Abstract
“Intelligence” is understood in different ways. Because humans are proud of their ability to speak, intelligence often includes the ability to communicate with others, to plan for the future, and to solve frequently encountered problems. Myxobacteria are among the most socially adept and ubiquitous of bacteria that live in the soil. To survive in nature, Myxobacteria communicate with their peers, using signals that elicit specific responses. Both swarming-growth and starvation-induced fruiting body development depend upon the specificity and effectiveness of signals passed between cells. Dynamic swarms spread outward, forming regular multi-cellular and multi-layered structures as they spread. Several different extra-cellular signals have been identified for fruiting body development and one is hypothesized for swarm development. Some extra-cellular signals are small, diffusible molecules. Others are protein molecules. The swarm signal appears to consist of structurally complex, protein to protein, contact junctions between pairs of side by side aligned cells. Each junction persists for less than a minute before disconnecting. After separating, both cells move on to make similar, transient connections with other cells. Eventually, the signal spreads across a prescribed population of communicating cells.
Collapse
Affiliation(s)
- Dale Kaiser
- Department of Biochemistry, Stanford University School of Medicine Stanford, CA, USA
| |
Collapse
|
15
|
Self-organization of bacterial biofilms is facilitated by extracellular DNA. Proc Natl Acad Sci U S A 2013; 110:11541-6. [PMID: 23798445 DOI: 10.1073/pnas.1218898110] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa. We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the "bulldozer" aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.
Collapse
|
16
|
Harvey CW, Du H, Xu Z, Kaiser D, Aranson I, Alber M. Interconnected cavernous structure of bacterial fruiting bodies. PLoS Comput Biol 2012; 8:e1002850. [PMID: 23300427 PMCID: PMC3531287 DOI: 10.1371/journal.pcbi.1002850] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 11/07/2012] [Indexed: 11/18/2022] Open
Abstract
The formation of spore-filled fruiting bodies by myxobacteria is a fascinating case of multicellular self-organization by bacteria. The organization of Myxococcus xanthus into fruiting bodies has long been studied not only as an important example of collective motion of bacteria, but also as a simplified model for developmental morphogenesis. Sporulation within the nascent fruiting body requires signaling between moving cells in order that the rod-shaped self-propelled cells differentiate into spores at the appropriate time. Probing the three-dimensional structure of myxobacteria fruiting bodies has previously presented a challenge due to limitations of different imaging methods. A new technique using Infrared Optical Coherence Tomography (OCT) revealed previously unknown details of the internal structure of M. xanthus fruiting bodies consisting of interconnected pockets of relative high and low spore density regions. To make sense of the experimentally observed structure, modeling and computer simulations were used to test a hypothesized mechanism that could produce high-density pockets of spores. The mechanism consists of self-propelled cells aligning with each other and signaling by end-to-end contact to coordinate the process of differentiation resulting in a pattern of clusters observed in the experiment. The integration of novel OCT experimental techniques with computational simulations can provide new insight into the mechanisms that can give rise to the pattern formation seen in other biological systems such as dictyostelids, social amoeba known to form multicellular aggregates observed as slugs under starvation conditions.
Collapse
Affiliation(s)
- Cameron W. Harvey
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Physics, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Huijing Du
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Zhiliang Xu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Dale Kaiser
- Department of Biochemistry, Stanford University, Stanford, California, United States of America
| | - Igor Aranson
- Material Science Division, Argonne National Lab, Argonne, Illinois, United States of America
- Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, United States of America
- * E-mail: (IA); (MA)
| | - Mark Alber
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Physics, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail: (IA); (MA)
| |
Collapse
|
17
|
Kaimer C, Berleman JE, Zusman DR. Chemosensory signaling controls motility and subcellular polarity in Myxococcus xanthus. Curr Opin Microbiol 2012; 15:751-7. [PMID: 23142584 DOI: 10.1016/j.mib.2012.10.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/28/2012] [Accepted: 10/15/2012] [Indexed: 01/04/2023]
Abstract
Myxococcus xanthus is a model system for the study of dynamic protein localization and cell polarity in bacteria. M. xanthus cells are motile on solid surfaces enabled by two forms of motility. Motility is controlled by the Che-like Frz pathway, which is essential for fruiting body formation and differentiation. The Frz signal is mediated by a GTPase/GAP protein pair that establishes cell polarity and directs the motility systems. Pilus driven motility at the leading pole of the cell requires dynamic localization of two ATPases and the coordinated production of EPS synthesis. Gliding motility requires dynamic movement of large protein complexes, but the mechanism by which this system generates propulsive force is still an active area of investigation.
Collapse
Affiliation(s)
- Christine Kaimer
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | | | | |
Collapse
|
18
|
Goldbeter A, Gérard C, Gonze D, Leloup JC, Dupont G. Systems biology of cellular rhythms. FEBS Lett 2012; 586:2955-65. [PMID: 22841722 DOI: 10.1016/j.febslet.2012.07.041] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 12/22/2022]
Abstract
Rhythms abound in biological systems, particularly at the cellular level where they originate from the feedback loops present in regulatory networks. Cellular rhythms can be investigated both by experimental and modeling approaches, and thus represent a prototypic field of research for systems biology. They have also become a major topic in synthetic biology. We review advances in the study of cellular rhythms of biochemical rather than electrical origin by considering a variety of oscillatory processes such as Ca++ oscillations, circadian rhythms, the segmentation clock, oscillations in p53 and NF-κB, synthetic oscillators, and the oscillatory dynamics of cyclin-dependent kinases driving the cell cycle. Finally we discuss the coupling between cellular rhythms and their robustness with respect to molecular noise.
Collapse
Affiliation(s)
- A Goldbeter
- Unité de Chronobiologie théorique, Faculté des Sciences, Université Libre de Bruxelles (ULB), Campus Plaine, CP 231, B-1050 Brussels, Belgium.
| | | | | | | | | |
Collapse
|