scholarly journals Ecological memory preserves phage resistance mechanisms in bacteria

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Antun Skanata ◽  
Edo Kussell
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Resistance Mechanisms ◽  
Linear Dynamical Systems ◽  
Molecular Binding ◽  
Ecological Memory ◽  
Wide Range ◽  
Host Pathogen ◽  
The Face ◽  
Evolutionarily Stable

AbstractBacterial defenses against phage, which include CRISPR-mediated immunity and other mechanisms, can carry substantial growth rate costs and can be rapidly lost when pathogens are eliminated. How bacteria preserve their molecular defenses despite their costs, in the face of variable pathogen levels and inter-strain competition, remains a major unsolved problem in evolutionary biology. Here, we present a multilevel model that incorporates biophysics of molecular binding, host-pathogen population dynamics, and ecological dynamics across a large number of independent territories. Using techniques of game theory and non-linear dynamical systems, we show that by maintaining a non-zero failure rate of defenses, hosts sustain sufficient levels of pathogen within an ecology to select against loss of the defense. This resistance switching strategy is evolutionarily stable, and provides a powerful evolutionary mechanism that maintains host-pathogen interactions, selects against cheater strains that avoid the costs of immunity, and enables co-evolutionary dynamics in a wide range of systems.

scholarly journals Ecological memory preserves phage resistance mechanisms in bacteria

2020 ◽  
Author(s):  
Antun Skanata ◽  
Edo Kussell
Keyword(s):  
Evolutionary Biology ◽  
Defense Mechanisms ◽  
Evolutionary Dynamics ◽  
Resistance Mechanisms ◽  
Term Survival ◽  
Linear Dynamical Systems ◽  
Ecological Memory ◽  
Wide Range ◽  
The Face

Defense mechanisms against pathogens are prevalent in nature, and their maintenance is critical for long-term survival of a species. Such mechanisms, which include CRISPR-mediated immunity in bacteria and the R genes in plants, carry substantial costs to organisms and can be rapidly lost when pathogens are eliminated. How a species preserves its molecular defenses despite their costs, in the face of variable pathogen levels, and across an ecology of localized patches remains a major unsolved problem in epidemiology and evolutionary biology. Using techniques of game theory and non-linear dynamical systems, we show that by maintaining a non-zero failure rate of immunity, hosts sustain sufficient levels of pathogen across an ecology to select against loss of the defense. This resistance switching strategy is evolutionarily stable, and provides a powerful evolutionary mechanism that maintains host-pathogen interactions and enables co-evolutionary dynamics in a wide range of systems.

Geographic Variation in Behavior

1999 ◽  
Keyword(s):  
Geographic Variation ◽  
Animal Behavior ◽  
Evolutionary Biology ◽  
Behavioral Characteristics ◽  
Behavioral Differences ◽  
Methodological Issues ◽  
Behavioral Evolution ◽  
Evolutionary Patterns ◽  
Wide Range

Studies of animal behavior often assume that all members of a species exhibit the same behavior. Geographic Variation in Behavior shows that, on the contrary, there is substantional variation within species across a wide range of taxa. Including work from pioneers in the field, this volume provides a balanced overview of research on behavioral characteristics that vary geographically. The authors explore the mechanisms by which behavioral differences evolve and examine related methodological issues. Taken together, the work collected here demonstrates that genetically based geographic variation may be far more widespread than previously suspected. The book also shows how variation in behavior can illuminate both behavioral evolution and general evolutionary patterns. Unique among books on behavior in its emphasis on geographic variation, this volume is a valuable new resource for students and researchers in animal behavior and evolutionary biology.

scholarly journals Deeply Learned Pose Invariant Image Analysis with Applications in 3D Face Recognition

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Naeem Ratyal ◽  
Imtiaz Ahmad Taj ◽  
Muhammad Sajid ◽  
Anzar Mahmood ◽  
Sohail Razzaq ◽  
...  
Keyword(s):  
Face Recognition ◽  
Superior Performance ◽  
Support Vector ◽  
Complex Nature ◽  
Alignment Algorithm ◽  
3D Face Recognition ◽  
3D Face ◽  
Norm Minimization ◽  
Wide Range ◽  
The Face

Face recognition aims to establish the identity of a person based on facial characteristics and is a challenging problem due to complex nature of the facial manifold. A wide range of face recognition applications are based on classification techniques and a class label is assigned to the test image that belongs to the unknown class. In this paper, a pose invariant deeply learned multiview 3D face recognition approach is proposed and aims to address two problems: face alignment and face recognition through identification and verification setups. The proposed alignment algorithm is capable of handling frontal as well as profile face images. It employs a nose tip heuristic based pose learning approach to estimate acquisition pose of the face followed by coarse to fine nose tip alignment using L2 norm minimization. The whole face is then aligned through transformation using knowledge learned from nose tip alignment. Inspired by the intrinsic facial symmetry of the Left Half Face (LHF) and Right Half Face (RHF), Deeply learned (d) Multi-View Average Half Face (d-MVAHF) features are employed for face identification using deep convolutional neural network (dCNN). For face verification d-MVAHF-Support Vector Machine (d-MVAHF-SVM) approach is employed. The performance of the proposed methodology is demonstrated through extensive experiments performed on four databases: GavabDB, Bosphorus, UMB-DB, and FRGC v2.0. The results show that the proposed approach yields superior performance as compared to existing state-of-the-art methods.

Lymphoedema after head and neck cancer treatment: an overview for clinical practice

2021 ◽  
Vol 26 (Sup4) ◽  
pp. S24-S29
Author(s):  
Claire Jeans ◽  
Bena Brown ◽  
Elizabeth C Ward ◽  
Anne E Vertigan
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Lymphatic System ◽  
Review Article ◽  
Psychological Issues ◽  
Wide Range ◽  
The Face ◽  
Protein Rich ◽  
The Impact

Lymphoedema is a disorder of the lymphatic system that presents as an atypical swelling and accumulation of protein-rich fluid within the interstitial spaces. Head and neck lymphoedema (HNL) is highly prevalent in patients who have been treated for head and neck cancer (HNC) and may manifest externally on the face and neck; internally within the oral cavity, pharynx or larynx; or as a combination of both. HNL is known to contribute to a wide range of physical, functional and psychological issues, and presents several unique challenges in terms of its management. This review article provides an overview of HNL for clinicians and aims to improve awareness of this condition and the impact it has on patients.

scholarly journals Adaptation limits ecological diversification and promotes ecological tinkering during the competition for substitutable resources

2018 ◽  
Vol 115 (44) ◽  
pp. E10407-E10416 ◽  
Author(s):  
Benjamin H. Good ◽  
Stephen Martis ◽  
Oskar Hallatschek
Keyword(s):  
Evolutionary Dynamics ◽  
Competitive Exclusion ◽  
Directional Selection ◽  
Ecological Niches ◽  
Ecological Diversification ◽  
Effective Competition ◽  
Uptake Rates ◽  
Wide Range ◽  
Dynamical Features ◽  
Adaptation Limits

Microbial communities can evade competitive exclusion by diversifying into distinct ecological niches. This spontaneous diversification often occurs amid a backdrop of directional selection on other microbial traits, where competitive exclusion would normally apply. Yet despite their empirical relevance, little is known about how diversification and directional selection combine to determine the ecological and evolutionary dynamics within a community. To address this gap, we introduce a simple, empirically motivated model of eco-evolutionary feedback based on the competition for substitutable resources. Individuals acquire heritable mutations that alter resource uptake rates, either by shifting metabolic effort between resources or by increasing the overall growth rate. While these constitutively beneficial mutations are trivially favored to invade, we show that the accumulated fitness differences can dramatically influence the ecological structure and evolutionary dynamics that emerge within the community. Competition between ecological diversification and ongoing fitness evolution leads to a state of diversification–selection balance, in which the number of extant ecotypes can be pinned below the maximum capacity of the ecosystem, while the ecotype frequencies and genealogies are constantly in flux. Interestingly, we find that fitness differences generate emergent selection pressures to shift metabolic effort toward resources with lower effective competition, even in saturated ecosystems. We argue that similar dynamical features should emerge in a wide range of models with a mixture of directional and diversifying selection.

4D ARCHITEKTŪROJE

2011 ◽  
Vol 35 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Kęstutis Lupeikis ◽  
Algimantas M. Mačiulis
Keyword(s):  
Modern Architecture ◽  
Fourth Dimension ◽  
Video Installation ◽  
Internal Structures ◽  
Wide Range ◽  
The Face ◽  
Intention To Change ◽  
Contemporary Architecture

Recently, among other processes in modern architecture, a lot more attention is expressed towards the fourth dimension (4D). This process is caused as an opposition to pragmatic functionalism, utilitarity, unification, formal deconstructyvism, sophistication. The expression of 4D in contemporary architecture is an intention to change the face of modern architecture, giving it more expressiveness, modern innovation. It results in specific aims and priorities of architectural expression. Architecture of today contains a variety of artistic areas (video, installation, painting, sculpture, graphics) as integral parts of its surface or internal structures. A building becomes an object of interdisciplinary art. The integration of interactive hypersurfaces in exteriors and interiors leads to various aspects of 4D in modern architecture. The paper discusses various aspects of 4D in architecture, excluding several marginal cases showing a wide range of aspects and priorities. Santrauka Pastaruoju metu, šalia kitų reiškinių, šiuolaikinėje architektūroje vis aktyviau reiškiasi ketvirtosios dimensijos vaidmuo. Šį procesą lemia priešprieša pragmatiškam funkcionalizmui, utilitarumui, unifikacijai, formaliam dekonstrukciniam laužymui, įmantrumui, daugžodžiavimui. 4D raišką šiuolaikinėje architektūroje formuoja siekis keisti architektūros „veidą“, suteikiant jai daugiau išraiškingumo, įtaigumo ir šiuolaikinio novatoriškumo. Tai lemia specifinius architektūrinės raiškos tikslus ir prioritetus. Šiuolaikinė architektūra įtraukia į save įvairių meno krypčių (videomenas, instaliacija, tapyba, skulptūra, grafika) elementus ne kaip atskirus meno objektus, o kaip neatsiejamus pastato paviršiaus ar vidaus struktūrinius darinius. Pastatas tampa tarpdisciplininiu meno objektu. Interaktyvių hiperpaviršių integravimasis eksterjere ir interjere lemia įvairius ketvirtosios dimensijos aspektus šiuolaikinėje architektūroje, kurie ir yra nagrinėjami šiame straipsnyje. Straipsnyje aptariami įvairūs ketvirtosios dimensijos šiuolaikinėje architektūroje aspektai ir sritys, išskiriami kraštutiniai, charakteringi atvejai, atspindintys platų tikslų ir prioritetų diapazoną. Aptariami, autorių manymu, charakteringiausi šios raiškos atvejai, daugiausiai dėmesio skiriant hiperpaviršių įtakai ketvirtosios dimensijos pasireiškimui šiuolaikinėje architektūroje.

scholarly journals Understanding the Evolutionary Games in NSCLC Microenvironment

2020 ◽  
Author(s):  
Ranjini Bhattacharya ◽  
Robert Vander Velde ◽  
Viktoriya Marusyk ◽  
Bina Desai ◽  
Artem Kaznatcheev ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Targeted Therapies ◽  
Evolutionary Dynamics ◽  
Fusion Gene ◽  
Evolutionary Game ◽  
Therapy Resistance ◽  
Resistance Mechanisms ◽  
Intrinsic Resistance ◽  
Frequency Changes

AbstractWhile initially highly successful, targeted therapies eventually fail as populations of tumor cells evolve mechanisms of resistance, leading to resumption of tumor growth. Historically, cell-intrinsic mutational changes have been the major focus of experimental and clinical studies to decipher origins of therapy resistance. While the importance of these mutational changes is undeniable, a growing body of evidence suggests that non-cell autonomous interactions between sub-populations of tumor cells, as well as with non-tumor cells within tumor microenvironment, might have a profound impact on both short term sensitivity of cancer cells to therapies, as well as on the evolutionary dynamics of emergent resistance. In contrast to well established tools to interrogate the functional impact of cell-intrinsic mutational changes, methodologies to understand non-cell autonomous interactions are largely lacking.Evolutionary Game Theory (EGT) is one of the main frameworks to understand the dynamics that drive frequency changes in interacting competing populations with different phenotypic strategies. However, despite a few notable exceptions, the use of EGT to understand evolutionary dynamics in the context of evolving tumors has been largely confined to theoretical studies. In order to apply EGT towards advancing our understanding of evolving tumor populations, we decided to focus on the context of the emergence of resistance to targeted therapies, directed against EML4-ALK fusion gene in lung cancers, as clinical responses to ALK inhibitors represent a poster child of limitations, posed by evolving resistance. To this end, we have examined competitive dynamics between differentially labelled therapy-naïve tumor cells, cells with cell-intrinsic resistance mechanisms, and cells with cell-extrinsic resistance, mediated by paracrine action of hepatocyte growth factor (HGF), within in vitro game assays in the presence or absence of front-line ALK inhibitor alectinib. We found that producers of HGF were the fittest in every pairwise game, while also supporting the proliferation of therapy-naïve cells. Both selective advantage of these producer cells and their impact on total population growth was a linearly increasing function of the initial frequency of producers until eventually reaching a plateau. Resistant cells did not significantly interact with the other two phenotypes. These results provide insights on reconciling selection driven emergence of subpopulations with cell non-cell autonomous resistance mechanisms, with lack of evidence of clonal dominance of these subpopulations. Further, our studies elucidate mechanisms for co-existence of multiple resistance strategies within evolving tumors. This manuscript serves as a technical report and will be followed up with a research paper in a different journal.

scholarly journals Evolution of correlated complexity in the radically different courtship signals of birds-of-paradise

2018 ◽  
Author(s):  
Russell A. Ligon ◽  
Christopher D. Diaz ◽  
Janelle L. Morano ◽  
Jolyon Troscianko ◽  
Martin Stevens ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Functional Integration ◽  
Empirical Support ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Birds Of Paradise ◽  
Analytical Approaches

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group - the birds-of-paradise - exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit - the courtship phenotype. Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness - functional overlap and interdependency - promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.Author SummaryAnimals frequently vary widely in ornamentation, even among closely related species. Understanding the patterns that underlie this variation is a significant challenge, requiring comparisons among drastically different traits - like comparing apples to oranges. Here, we use novel analytical approaches to quantify variation in ornamental diversity and richness across the wildly divergent birds-of-paradise, a textbook example of how sexual selection can profoundly shape organismal phenotypes. We find that color and acoustic complexity, along with behavior and acoustic complexity, are positively correlated across evolutionary time-scales. Positive covariation among ornament classes suggests that selection is acting on correlated suites of traits - a composite courtship phenotype - and that this integration may be partially responsible for the extreme variation we see in birds-of-paradise.

scholarly journals Protecting the North Sea: New research for biodiversity recovery.

2020 ◽  
Author(s):  
Oceana ◽  
Helena Álvarez ◽  
Allison L. Perry ◽  
Jorge Blanco ◽  
Silvia Garcia ◽  
...  
Keyword(s):  
North Sea ◽  
Marine Biodiversity ◽  
Legal Requirements ◽  
Marine Life ◽  
The North ◽  
Marine Habitats ◽  
Wide Range ◽  
The Face ◽  
The North Sea ◽  
New Research

To help fill gaps in knowledge about marine biodiversity in the North Sea, Oceana carried out two eight week research expeditions, in 2016 and 2017. Oceana’s surveys documented a wide range of habitats and species that are considered priorities for conservation, under national, EU, and international frameworks that recognise them as threatened and/or establish legal requirements for their protection.Oceana’s research has underscored the fact that much remains to be discovered about marine life on the seabed of the North Sea. Continued research is critical for informing efforts to recover biodiversity, an urgent priority in the face of the multiple, intense pressures facing the North Sea’s marine habitats and species.

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