scholarly journals Competition for space during bacterial colonization of a surface

2015 ◽  
Vol 12 (110) ◽  
pp. 20150608 ◽  
Author(s):  
Diarmuid P. Lloyd ◽  
Rosalind J. Allen
Keyword(s):  
Bacterial Colonization ◽  
Model Systems ◽  
Ecological Interactions ◽  
Bacterial Populations ◽  
Competition For Space ◽  
Colonization Success ◽  
Bacterial Model ◽  
Lag Times ◽  
Empty Habitat ◽  
As Effects

Competition for space is ubiquitous in the ecology of both microorganisms and macro-organisms. We introduce a bacterial model system in which the factors influencing competition for space during colonization of an initially empty habitat can be tracked directly. Using fluorescence microscopy, we follow the fate of individual Escherichia coli bacterial cell lineages as they undergo expansion competition (the race to be the first to colonize a previously empty territory), and as they later compete at boundaries between clonal territories. Our experiments are complemented by computer simulations of a lattice-based model. We find that both expansion competition, manifested as differences in individual cell lag times, and boundary competition, manifested as effects of neighbour cell geometry, can play a role in colonization success, particularly when lineages expand exponentially. This work provides a baseline for investigating how ecological interactions affect colonization of space by bacterial populations, and highlights the potential of bacterial model systems for the testing and development of ecological theory.

Multifaceted Impacts of Bacteriophages in the Plant Microbiome

2018 ◽  
Vol 56 (1) ◽  
pp. 361-380 ◽  
Author(s):  
Britt Koskella ◽  
Tiffany B. Taylor
Keyword(s):  
Host Plant ◽  
Future Study ◽  
Plant Pathogens ◽  
Ecological Interactions ◽  
Selection Pressures ◽  
Bacterial Populations ◽  
Associated Bacteria ◽  
Open Questions ◽  
Microbe Interactions ◽  
Plant Microbiome

Plant-associated bacteria face multiple selection pressures within their environments and have evolved countless adaptations that both depend on and shape bacterial phenotype and their interaction with plant hosts. Explaining bacterial adaptation and evolution therefore requires considering each of these forces independently as well as their interactions. In this review, we examine how bacteriophage viruses (phages) can alter the ecology and evolution of plant-associated bacterial populations and communities. This includes influencing a bacterial population's response to both abiotic and biotic selection pressures and altering ecological interactions within the microbiome and between the bacteria and host plant. We outline specific ways in which phages can alter bacterial phenotype and discuss when and how this might impact plant-microbe interactions, including for plant pathogens. Finally, we highlight key open questions in phage-bacteria-plant research and offer suggestions for future study.

scholarly journals Scale-dependent tipping points of bacterial colonization resistance

2021 ◽  
Author(s):  
Yuya Karita ◽  
David T Limmer ◽  
Oskar Hallatschek
Keyword(s):  
Bacterial Colonization ◽  
Biophysical Model ◽  
Tipping Points ◽  
Colonization Resistance ◽  
Wide Range ◽  
Colonization Success ◽  
Dental Cavities ◽  
The Stability ◽  
Cell Motion ◽  
Stability And Resilience

Bacteria are efficient colonizers of a wide range of secluded micro-habitats, such as soil pores, skin follicles, dental cavities or crypts in gut-like environments. Although numerous factors promoting or obstructing stable colonization have been identified, we currently lack systematic approaches to explore how population stability and resilience depend on the scale of the micro-habitat. Using a microfluidic device to grow bacteria in crypt-like incubation chambers of systematically varied lengths, we found that the incubation scale can sensitively tune bacterial colonization success and resistance against invaders. Small crypts are un-colonizable, intermediately sized crypts can stably support dilute populations, while beyond a second critical lengthscale, populations phase-separate into a dilute and a jammed region. We demonstrate that the jammed state confers extreme colonization resistance, even if the resident strain is suppressed by an antibiotic. Combined with a flexible biophysical model, we show that scale acts as an environmental filter that can be tuned via the competition between growth and collective cell motion. More broadly, our observations underscore that scale can profoundly bias experimental outcomes in microbial ecology. Systematic, flow-adjustable lengthscale variations may serve as a promising strategy to elucidate further scale-sensitive tipping points and to rationally modulate the stability and resilience of microbial colonizers.

Bacterial colonization patterns of intactPinus sylvestrismycorrhizospheres in dry pine forest soil: an electron microscopy study

1997 ◽  
Vol 43 (11) ◽  
pp. 1017-1035 ◽  
Author(s):  
E. -L. Nurmiaho-Lassila ◽  
S. Timonen ◽  
K. Haahtela ◽  
R. Sen
Keyword(s):  
Electron Microscopy ◽  
Pinus Sylvestris ◽  
Forest Soil ◽  
Bacterial Colonization ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Paxillus Involutus ◽  
Intracellular Bacteria ◽  
Bacterial Populations ◽  
Suillus Bovinus

The bacterial populations associated with different plant and fungal habitats of intact Pinus sylvestris – Suillus bovinus or Pinus sylvestris – Paxillus involutus ectomycorrhizospheres grown in natural forest soil were examined by scanning and transmission electron microscopy. Surfaces of nonmycorrhizal Pinus sylvestris roots hosted large numbers of morphologically distinct bacteria. Bacteria were detected on the mantle surfaces and at inter- and intra-cellular locations in the mantle and Hartig net of Suillus bovinus mycorrhizas. The fungal strands were colonized by only a few bacteria unlike the outermost external fine hyphae on which extensive monolayers of bacteria were attached. The mycorrhizas of Paxillus involutus were mostly devoid of bacteria, but the intact external mycelium supported both bacterial colonies and solitary bacteria. Intracellular bacteria were not present in Paxillus involutus hyphae. In both mycorrhizal systems, bacterial aggregation and attachment to hyphae were mediated with electron-dense or -translucent material. Our study shows that the Pinus sylvestris mycorrhizospheres formed by two different ectomycorrhizal fungi are clearly dissimilar habitats for mycorrhizosphere-associated bacteria. Additionally, the spatially and physiologically defined mycorrhizosphere habitats were shown to host distinct populations of bacteria.Key words: ectomycorrhiza, intracellular bacteria, Paxillus involutus, soil bacteria, Suillus bovinus.

The Effect of NaCl on Survival of Shigella flexneri in Broth as Affected by Temperature and pH†‡

2002 ◽  
Vol 65 (5) ◽  
pp. 774-779 ◽  
Author(s):  
LAURA L. ZAIKA
Keyword(s):  
Shigella Flexneri ◽  
Foodborne Pathogen ◽  
Brain Heart Infusion ◽  
Major Effect ◽  
Plate Count ◽  
Bacterial Survival ◽  
Two Phase ◽  
Bacterial Populations ◽  
Lag Times ◽  
D Values

Shigella, a major foodborne pathogen, survives well in salt-containing environments. However, systematic data are scarce. We studied the behavior of Shigella flexneri 5348 in brain heart infusion broth (pH 4 to 6) containing 0.5 to 8% NaCl. Stationary-phase cells were inoculated into sterile media at initial concentrations of 6 to 7 log10 CFU/ml and incubated at 12 to 37°C. Bacterial population sizes were determined periodically by plate counts. Survivor curves were derived from plate count data by using a two-phase linear model to determine lag times and slopes of the curves, from which decimal reduction times (D-values) and times to a 4-log10 inactivation (T4D) were calculated. In media of pH 6, the bacteria grew in the presence of ≤6% NaCl at 19 and 37°C and in the presence of ≤7% NaCl at 28°C. In media of pH 5, growth was observed in the presence of ≤2, ≤4, ≤4, and 0.5% NaCl at 37, 28, 19, and 12°C, respectively. Growth did not occur and bacterial populations gradually declined in media of pH 4. While NaCl had a major effect on growth, bacterial survival was affected to a lesser extent. Lag times decreased with increasing NaCl levels; however, the effect on D-values and T4D values was less pronounced. The average T4D values for media of pH 4 containing 0.5 to 6% NaCl were 4, 13, 23, and 61 days at 37, 28, 19, and 12°C, respectively. These results show that S. flexneri is salt tolerant and suggest that salty foods may serve as vehicles for infection with this bacterium.

scholarly journals Disturbance opens recruitment sites for bacterial colonization in activated sludge

2015 ◽  
Author(s):  
David Vuono ◽  
Junko Munakata Marr ◽  
John Spear ◽  
Jörg Drewes
Keyword(s):  
Activated Sludge ◽  
Bacterial Colonization ◽  
Immigrant Community ◽  
Community Members ◽  
Bacterial Populations ◽  
Operational Conditions ◽  
Local Diversity ◽  
Disturbance Gradient ◽  
Solids Retention ◽  
Microbial Resource Management

Little is known about the role of immigration in shaping bacterial communities or the factors that may dictate success or failure of colonization by bacteria from regional species pools. To address these knowledge gaps, the influence of bacterial colonization into an ecosystem (activated sludge bioreactor) was measured through a disturbance gradient (successive decreases in the parameter solids retention time) relative to stable operational conditions. Through a DNA sequencing approach, we show that the most abundant bacteria within the immigrant community have a greater probability of colonizing the receiving ecosystem, but mostly as low abundance community members. Only during the disturbance do some of these bacterial populations significantly increase in abundance beyond background levels and in few cases become dominant community members post-disturbance. Two mechanisms facilitate the enhanced enrichment of immigrant populations during disturbance: 1) the availability of resources left unconsumed by established species and 2) the increased availability of niche space for colonizers to establish and displace resident populations. Thus, as a disturbance decreases local diversity, recruitment sites become available to promote colonization. This work advances our understanding of microbial resource management and diversity maintenance in complex ecosystems.

scholarly journals Ecology dictates evolution? About the importance of genetic and ecological constraints in adaptation

2018 ◽  
Author(s):  
Marjon G. J. de Vos ◽  
Sijmen E Schoustra ◽  
J. Arjan G. M. de Visser
Keyword(s):  
Microbial Communities ◽  
Major Determinant ◽  
Model Systems ◽  
Adaptive Landscape ◽  
Ecological Interactions ◽  
Ecological Constraints ◽  
Adaptive Constraints

The topography of the adaptive landscape is a major determinant of the course of evolution. In this review we use the adaptive landscape metaphor to highlight the effect of ecology on evolution. We describe how ecological interactions modulate the shape of the adaptive landscape, and how this affects adaptive constraints. We focus on microbial communities as model systems.

The driving role of microhabitats in soil ecology: rebuilding artificial 3D soil-like nanostructured microhabitats for experimental reproducible works

2021 ◽  
Author(s):  
Fabrizio De Cesare ◽  
Elena Di Mattia ◽  
Antonella Macagnano
Keyword(s):  
Soil Ph ◽  
Model Systems ◽  
Natural Soil ◽  
Phenotypic Traits ◽  
Local Concentration ◽  
Bacterial Populations ◽  
Soil Features ◽  
Soil Mesocosms ◽  
Soil Ecosystems ◽  
Soil Components

<p>Soil ecosystems are composed of microhabitats that often differ in composition and ecological strategies at the microscale. Besides, the assumption that soil organism behaviour at the ecosystem level is similar to that at microscale may drive unexpected findings. Soil pH at microsites either can differ significantly from whole soil pH. Moreover, the large porosity measured in the whole soil can contrast with water, nutrient, air and waste flow limitations and dramatic constraints to microbial mobility and access to food, when analysed at the microscale, consequent to local pore geometry, connectivity and tortuosity. Incidentally, soil microorganisms, which are present in billions of individuals per gram of soil, have micrometre sizes and prevalently interact with the other soil components at the nano-to-microscale. They colonise soil microhabitat based on the local concentration and composition of air, nutrients and materials. Finally, different organic materials and minerals in the soil induce distinct interactions at microsites, generating diverse organo-mineral associations and different microbial populations. </p><p>The study of soil microhabitats can enable comprehending how the microsites' dynamics can drive to ecosystems' macroscale behaviours. However, the study of soil microhabitats in real conditions, even when investigated in soil mesocosms and microcosms, can be challenging or require complicated and expensive instrumentations to achieve such outcomes. </p><p>The rebuilding of soil microhabitats in model systems can help study the microhabitats' mutual interactions at the microscale. However, it is impossible to reproduce any possible combination of soil components to replicate the multitude of microhabitats existing in natural soil ecosystems. Then, approximations are necessary. </p><p>The present study proposes to recreate an artificial model 3D soil-like microhabitat resulting from the aggregation of the major classes of soil components (mineral particles, organic polymeric components, and microorganisms) in nano- to macro-architectures to study organo-mineral-microbe interactions at the microscale, and enable reproducible works. Electrospinning/electrospraying technologies were chosen for their extreme versatility in creating self-standing 3D complex, porous and functional structures and their proven capacity to permit microbes to grow on the resulting composite fibrous frameworks.</p><p>Bacteria strains of <em>Pseudomonas fluorescens</em> and <em>Burkholderia terricola</em>, typical microbial species populating the rhizosphere soils, will be utilised as microhabitat microbial components for generating a simplified microbiome in the 3D soil-like nanostructures. At first instance, we intended to use microscopy (e.g. SEM, TEM, confocal) as the tool of choice to investigate over time the spatial distribution of bacterial populations throughout the artificial nanostructured soil microhabitat here reproduced, the release of EPS by the bacterial populations and possible interactions. The proposed 3D soil-like nanostructures are supposed to provide the possibility of investigating the microbial lifestyle in microhabitats at different scales, from nm to mm, then linking microbial phenotypic traits to specific soil features.</p>

scholarly journals Lipooligosaccharides Containing Phosphorylcholine Delay Pulmonary Clearance of Nontypeable Haemophilus influenzae

2008 ◽  
Vol 76 (5) ◽  
pp. 2037-2043 ◽  
Author(s):  
Bing Pang ◽  
Dana Winn ◽  
Ryan Johnson ◽  
Wenzhou Hong ◽  
Shayla West-Barnette ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Bacterial Resistance ◽  
Serial Passage ◽  
Model Systems ◽  
Immunofluorescent Staining ◽  
Mouse Lung ◽  
Chronic Obstructive ◽  
Nontypeable Haemophilus Influenzae ◽  
Bacterial Populations ◽  
Pulmonary Clearance

ABSTRACT Nontypeable Haemophilus influenzae (NTHi) causes pulmonary infections in patients with chronic obstructive pulmonary disease and other mucociliary clearance defects. Like many bacteria inhabiting mucosal surfaces, NTHi produces lipooligosaccharide (LOS) endotoxins that lack the O side chain. Persistent NTHi populations express a discrete subset of LOS glycoforms, including those containing phosphorylcholine (PCho). In this study, we compared two NTHi strains with isogenic mutants lacking PCho for clearance from mice following pulmonary infection. Consistent with data from other model systems, populations of the strains NTHi 2019 and NTHi 86-028NP recovered from mouse lung contained an increased proportion of PCho+ variants compared to that in the inocula. PCho− mutants were more rapidly cleared. Serial passage of NTHi increased both PCho content and bacterial resistance to clearance, and no such increases were observed for PCho− mutants. Increased PCho content was also observed in NTHi populations within non-endotoxin-responsive C3H/HeJ and Toll-like receptor 4 null (TLR4−/−) mice, albeit at later times postinfection. Changes in bacterial subpopulations and clearance were unaffected in TLR2−/− mice compared to the subpopulations in and clearance from mice of the parental strain. The clearance of PCho− mutants occurred at earlier time points in both strain backgrounds and in all types of mice. Comparison of bacterial populations in lung tissue cryosections by immunofluorescent staining showed sparse bacteria within the air spaces of C57BL/6 mice and large bacterial aggregates within the lungs of MyD88−/− mice. These results indicate that PCho promotes bacterial resistance to pulmonary clearance early in infection in a manner that is at least partially independent of the TLR4 pathway.

scholarly journals Heat-Treated Bifidobacterium longum CECT-7347: A Whole-Cell Postbiotic with Antioxidant, Anti-Inflammatory, and Gut-Barrier Protection Properties

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 536
Author(s):  
Patricia Martorell ◽  
Beatriz Alvarez ◽  
Silvia Llopis ◽  
Veronica Navarro ◽  
Pepa Ortiz ◽  
...  
Keyword(s):  
Functional Properties ◽  
Bacterial Colonization ◽  
Bifidobacterium Longum ◽  
Model Systems ◽  
Gut Health ◽  
Gut Barrier ◽  
Whole Cell ◽  
Heat Treated ◽  
Anti Inflammatory ◽  
Immune System Modulation

Non-viable preparations of probiotics, as whole-cell postbiotics, attract increasing interest because of their intrinsic technological stability, and their functional properties, such as immune system modulation, gut barrier maintenance, and protection against pathogens. However, reports on Bifidobacteria-derived postbiotics remain scarce. This study aims to demonstrate the functional properties of a heat-treated (HT), non-viable, Bifidobacterium longum strain, CECT-7347, a strain previously selected for its anti-inflammatory phenotype and ability to improve biomarkers of intestinal integrity in clinical trials. The study used the nematode Caenorhabditis elegans and HT-29 cell cultures as eukaryotic model systems. Our results show that HT-CECT-7347 preserves the capacity to protect against oxidative stress damage, while it also reduces acute inflammatory response and gut-barrier disruption, and inhibits bacterial colonization, by activating pathways related to innate immune function. These findings highlight the interest of the ingredient as a novel postbiotic and pave the way to broaden the range of HT-CECT-7347 applications in gut health.

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