scholarly journals Biofilm and swarming emergent behaviours controlled through the aid of biophysical understanding and tools

2020 ◽  
Vol 48 (6) ◽  
pp. 2903-2913
Author(s):  
Iago Grobas ◽  
Dario G. Bazzoli ◽  
Munehiro Asally
Keyword(s):  
Bacterial Communities ◽  
New Technologies ◽  
Computational Modelling ◽  
Emergent Properties ◽  
Emergent Phenomena ◽  
Physical Stimuli ◽  
Future Potential ◽  
Physical Interactions ◽  
Biofilm Development ◽  
Emergent Behaviours

Bacteria can organise themselves into communities in the forms of biofilms and swarms. Through chemical and physical interactions between cells, these communities exhibit emergent properties that individual cells alone do not have. While bacterial communities have been mainly studied in the context of biochemistry and molecular biology, recent years have seen rapid advancements in the biophysical understanding of emergent phenomena through physical interactions in biofilms and swarms. Moreover, new technologies to control bacterial emergent behaviours by physical means are emerging in synthetic biology. Such technologies are particularly promising for developing engineered living materials (ELM) and devices and controlling contamination and biofouling. In this minireview, we overview recent studies unveiling physical and mechanical cues that trigger and affect swarming and biofilm development. In particular, we focus on cell shape, motion and density as the key parameters for mechanical cell–cell interactions within a community. We then showcase recent studies that use physical stimuli for patterning bacterial communities, altering collective behaviours and preventing biofilm formation. Finally, we discuss the future potential extension of biophysical and bioengineering research on microbial communities through computational modelling and deeper investigation of mechano-electrophysiological coupling.

Towards a Classification Framework for Mobile Location Based Services

2011 ◽  
pp. 67-85 ◽  
Author(s):  
George M. Giaglis ◽  
Panos Kourouthanassis ◽  
Argiros Tsamakos
Keyword(s):  
Business Models ◽  
New Technologies ◽  
Geographical Location ◽  
Mobile User ◽  
Location Based Services ◽  
Location Services ◽  
Mobile Location ◽  
Classification Framework ◽  
Future Potential ◽  
Pricing Schemes

The emerging world of mobile commerce is characterized by a multiplicity of exciting new technologies, applications, and services. Among the most promising ones will be the ability to identify the exact geographical location of a mobile user at any time. This ability opens the door to a new world of innovative services, which are commonly referred to as Mobile Location Services (MLS). This chapter aims at exploring the fascinating world of MLS, identifying the most pertinent issues that will determine its future potential, and laying down the foundation of a new field of research and practice. The contribution of our analysis is encapsulated into a novel classification of mobile location services that can serve both as an analytical toolkit and an actionable framework that systemizes our understanding of MLS applications, underlying technologies, business models, and pricing schemes.

scholarly journals Respiratory Heterogeneity Shapes Biofilm Formation and Host Colonization in Uropathogenic Escherichia coli

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Connor J. Beebout ◽  
Allison R. Eberly ◽  
Sabrina H. Werby ◽  
Seth A. Reasoner ◽  
John R. Brannon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Extracellular Matrix ◽  
Bacterial Communities ◽  
Spatial Organization ◽  
Bet Hedging ◽  
Content Type ◽  
Dna Organization ◽  
Quinol Oxidases ◽  
Biofilm Development ◽  
Biofilm Community

ABSTRACT Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization to the biofilm community such that biofilm residents can benefit from the production of common goods while being protected from exogenous insults. Spatial organization is driven by the presence of chemical gradients, such as oxygen. Here we show that two quinol oxidases found in Escherichia coli and other bacteria organize along the biofilm oxygen gradient and that this spatially coordinated expression controls architectural integrity. Cytochrome bd, a high-affinity quinol oxidase required for aerobic respiration under hypoxic conditions, is the most abundantly expressed respiratory complex in the biofilm community. Depletion of the cytochrome bd-expressing subpopulation compromises biofilm complexity by reducing the abundance of secreted extracellular matrix as well as increasing cellular sensitivity to exogenous stresses. Interrogation of the distribution of quinol oxidases in the planktonic state revealed that ∼15% of the population expresses cytochrome bd at atmospheric oxygen concentration, and this population dominates during acute urinary tract infection. These data point toward a bet-hedging mechanism in which heterogeneous expression of respiratory complexes ensures respiratory plasticity of E. coli across diverse host niches. IMPORTANCE Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization in the biofilm community. Here we demonstrate that oxygen gradients in uropathogenic Escherichia coli (UPEC) biofilms lead to spatially distinct expression programs for quinol oxidases—components of the terminal electron transport chain. Our studies reveal that the cytochrome bd-expressing subpopulation is critical for biofilm development and matrix production. In addition, we show that quinol oxidases are heterogeneously expressed in planktonic populations and that this respiratory heterogeneity provides a fitness advantage during infection. These studies define the contributions of quinol oxidases to biofilm physiology and suggest the presence of respiratory bet-hedging behavior in UPEC.

Metal ion binding by humic substances as emergent functions of labile supramolecular assemblies

2020 ◽  
Vol 17 (3) ◽  
pp. 252 ◽  
Author(s):  
Elena A. Vialykh ◽  
Dennis R. Salahub ◽  
Gopal Achari
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Substances ◽  
Metal Binding ◽  
Metal Ion ◽  
Computational Modelling ◽  
Intermolecular Forces ◽  
Metal Complexation ◽  
Emergent Properties ◽  
Metal Availability

Environmental contextThe fundamental basis for the high flexibility of humic substances is still unclear, though it is crucial for the understanding of metal bioavailability and toxicity in soil and aqueous environments. We show at the molecular level how characteristics of organic matter affect metal binding depending on the environmental conditions. Such understanding will help in the modulation of metal availability in soil and water in changing environmental situations. AbstractIn this work, we explore the hypothesis that humic substances (HS) can be perceived as labile supramolecular assemblages, the functioning of which is mainly determined by chemical composition and characteristics, the size of molecular units and weak intermolecular forces, rather than the exact primary structure of molecular moieties and their spatial configuration. To test the hypothesis, 72 computational models of three different organic mixtures were composed. The formation of inner and outer sphere metal–ligand complexes, metal binding sites, complex configurations, binding energies and aggregation/dissolution as emergent properties of HS were determined under various conditions. The results of computational modelling revealed that: (i) the highest Cu2+ binding (55.6%) was by the SRFA-22 organic model, which represents low-molecular-weight fulvic acids. In contrast, the highest amount of inner-sphere Mg–organic matter complex (63.4%) was formed in SRHA-6, which has higher-molecular-weight constituents. Therefore, a correlation between the type of cation, the system aromaticity and the extent of metal complexation is proposed. (ii) Increase of metal ion concentration and decrease of water content resulted in an increase in the number of hydrogen bonds and more compact and stable aggregates with lower hydrophilic and higher hydrophobic surface areas in SRFA-22. However, in SRHA-6, the results varied owing to the competition between metal binding, H-bonding and non-polar interactions in the structural arrangement of the aggregates. In general, the aggregation process, driven by metal complexation and water removal, resulted in the formation of more stable conformers, with lower potential energy, with the only exception of SRHA-6–Cu.

scholarly journals Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1230 ◽  
Author(s):  
Paul Cătălin Balaure ◽  
Alexandru Mihai Grumezescu
Keyword(s):  
Life Cycle ◽  
Molecular Mechanisms ◽  
Antimicrobial Agents ◽  
Current Knowledge ◽  
Emergent Properties ◽  
Bacterial Cells ◽  
Life Cycle Stages ◽  
Fouling Release ◽  
Biofilm Development ◽  
And Control

Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of “emergent properties”, meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both “fouling-resistant” and “fouling release” strategies are addressed as well as their synergic combination in a single unique nanoplatform.

scholarly journals A psychophysically-tuned computational model of human primary visual cortex produces geometric optical illusions

2020 ◽  
Author(s):  
Chrysa Retsa ◽  
Ana Hernando Ariza ◽  
Nathanael W. Noordanus ◽  
Lorenzo Ruffoni ◽  
Micah M. Murray ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Computational Model ◽  
Primary Visual Cortex ◽  
Computational Modelling ◽  
Access Point ◽  
Optical Illusions ◽  
Long Range Interactions ◽  
Physical Stimuli ◽  
Trial Basis ◽  
Underlying Mechanisms

AbstractGeometrical optical illusion (GOIs) are mismatches between physical stimuli and perception. GOIs provide an access point to study the interplay between sensation and perception, yet there is scant quantitative investigation of the extent to which different GOIs rely on similar or distinct brain mechanisms. We addressed this knowledge gap. First, 30 healthy adults reported quantitatively their perceptual biases with three GOIs, whose physical properties parametrically varied on a trial-by-trial basis. Biases observed with one GOI were unrelated to those observed with another GOI, suggestive of (partially) distinct underlying mechanisms. Next, we used these psychophysical results to tune a computational model of primary visual cortex that combines parameters of orientation, selectivity, intra-cortical connectivity, and long-range interactions. We showed that similar biases could be generated in-silico, mirroring those observed in humans. Such results provide a roadmap whereby computational modelling, informed by human psychophysics, can reveal likely mechanistic underpinnings of perception.

scholarly journals Emergent properties of a computational model of tumour growth

2016 ◽  
Author(s):  
Pan Pantziarka
Keyword(s):  
Tumour Growth ◽  
Emergent Properties ◽  
Molecular Pathways ◽  
Cell Competition ◽  
System A ◽  
Accelerated Repopulation ◽  
Key Drivers ◽  
Tumour Growth Model ◽  
Emergent Behaviours

While there have been enormous advances in our understanding of the genetic drivers and molecular pathways involved in cancer in recent decades, there also remain key areas of dispute with respect to fundamental theories of cancer. The accumulation of vast new datasets from genomics and other fields, in addition to detailed descriptions of molecular pathways, cloud the issues and lead to ever greater complexity. One strategy in dealing with such complexity is to develop models to replicate salient features of the system and therefore to generate hypotheses which reflect on the real system. A simple tumour growth model is outlined which displays emergent behaviours that correspond to a number of clinically relevant phenomena including tumour growth, intra-tumour heterogeneity, growth arrest and accelerated repopulation following cytotoxic insult. Analysis of model data suggests that the processes of cell competition and apoptosis are key drivers of these emergent behaviours. Questions are raised as to the role of cell competition and cell death in physical cancer growth and the relevance that these have to cancer research in general is discussed.

M-Learning in the Middle East

2015 ◽  
pp. 176-199 ◽  
Author(s):  
Evangelia Marinakou ◽  
Charalampos Giousmpasoglou
Keyword(s):  
Higher Education ◽  
University Students ◽  
New Technologies ◽  
Learning Approach ◽  
Learning Tools ◽  
Limited Extent ◽  
Learning And Teaching ◽  
E Learning ◽  
Future Potential ◽  
Views And Perceptions

The introduction of e-learning in higher education has brought radical changes in the way undergraduate and postgraduate programmes are designed and delivered. University students now have access to their courses anytime, anywhere, which makes e-learning and m-learning popular and fashionable among university students globally. Nevertheless, instructors are now challenged, as they have to adopt new pedagogies in learning and teaching. This chapter explores the adoption of m-learning at universities in the Kingdom of Bahrain, as well as the relevant current developments and challenges related to the major stakeholders (educators and students) in higher education. It mainly investigates the educators' views and perceptions of m-learning, as well as its future potential in higher education. Most of the educators use m-learning tools to some limited extent, and there is still opportunity to reach full integration with curriculum and the blended learning approach. Further, it is proposed that professional development should be provided to instructors to enable them to use the available new technologies in an appropriate and effective way.

Comparing the microbial characteristics of rainwater in two operating rainwater tanks with different surface-to-volume ratios

2011 ◽  
Vol 64 (3) ◽  
pp. 627-631 ◽  
Author(s):  
Mikyeong Kim ◽  
Gippeum Bak ◽  
Mooyoung Han
Keyword(s):  
Bacterial Communities ◽  
Suspended Solids ◽  
Volume Ratio ◽  
Storage Tanks ◽  
Microbial Ecosystems ◽  
Rainwater Tank ◽  
Microbial Characteristics ◽  
Biofilm Development ◽  
Rainwater Tanks

In this study, the microbial characteristics of rainwater in two tanks with different surface-to-volume ratios were investigated and compared to determine how the internal design features of storage tanks affect water quality. The particle and nutrient parameters of the rainwater, including turbidity, suspended solids, total organic carbon, and total phosphate, were lower in Tank 2, which had a surface-to-volume ratio 7.5 times greater than that of Tank 1. In addition, although the rainwater was collected from the same catchment area, the water in Tank 1 had greater numbers of bacteria, and the bacterial communities in the water differed between the two storage tanks. It appears that the differences in the inside surface structures of the rainwater tanks affected the microbial ecosystems. Increasing the surface-to-volume ratio in rainwater tanks may affect rainwater quality, because this extends the area for biofilm development. Further study of the role of biofilm in rainwater tank is required precisely, and its function needs to be considered in the design and management of rainwater tanks.

scholarly journals Emergent properties of a computational model of tumour growth

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2176 ◽  
Author(s):  
Pan Pantziarka
Keyword(s):  
Tumour Growth ◽  
Emergent Properties ◽  
Molecular Pathways ◽  
Cell Competition ◽  
System A ◽  
Accelerated Repopulation ◽  
Key Drivers ◽  
Tumour Growth Model ◽  
Emergent Behaviours

While there have been enormous advances in our understanding of the genetic drivers and molecular pathways involved in cancer in recent decades, there also remain key areas of dispute with respect to fundamental theories of cancer. The accumulation of vast new datasets from genomics and other fields, in addition to detailed descriptions of molecular pathways, cloud the issues and lead to ever greater complexity. One strategy in dealing with such complexity is to develop models to replicate salient features of the system and therefore to generate hypotheses which reflect on the real system. A simple tumour growth model is outlined which displays emergent behaviours that correspond to a number of clinically relevant phenomena including tumour growth, intra-tumour heterogeneity, growth arrest and accelerated repopulation following cytotoxic insult. Analysis of model data suggests that the processes of cell competition and apoptosis are key drivers of these emergent behaviours. Questions are raised as to the role of cell competition and cell death in physical cancer growth and the relevance that these have to cancer research in general is discussed.

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