scholarly journals Immune Loss as a Driver of Coexistence During Host-Phage Coevolution

2017 ◽  
Author(s):  
Jake L Weissman ◽  
Rayshawn Holmes ◽  
Rodolphe Barrangou ◽  
Sylvain Moineau ◽  
William F Fagan ◽  
...  
Keyword(s):  
Immune System ◽  
Constant Pressure ◽  
Arms Race ◽  
Bacterial Host ◽  
Viral Pathogens ◽  
Fitness Tradeoffs ◽  
Parameter Ranges ◽  
Selective Regime ◽  
Mixed Systems

AbstractBacteria and their viral pathogens face constant pressure for augmented immune and infective capabilities, respectively. Under this reciprocally imposed selective regime, we expect to see a runaway evolutionary arms race, ultimately leading to the extinction of one species. Despite this prediction, in many systems host and pathogen coexist with minimal coevolution even when well-mixed. Previous work explained this puzzling phenomenon by invoking fitness tradeoffs, which can diminish an arms race dynamic. Here we propose that the regular loss of immunity by the bacterial host can also produce host-phage coexistence. We pair a general model of immunity with an experimental and theoretical case study of the CRISPR-Cas immune system to contrast the behavior of tradeoff and loss mechanisms in well-mixed systems. We find that, while both mechanisms can produce stable coexistence, only immune loss does so robustly within realistic parameter ranges.

scholarly journals Diversity of molecular mechanisms used by anti-CRISPR proteins: the tip of an iceberg?

2020 ◽  
Vol 48 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Pierre Hardouin ◽  
Adeline Goulet
Keyword(s):  
Immune System ◽  
Structure Function ◽  
Defense Mechanisms ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Arms Race ◽  
Allosteric Inhibitors ◽  
Fundamental Knowledge ◽  
Attack And Defense ◽  
Fine Tune

Bacteriophages (phages) and their preys are engaged in an evolutionary arms race driving the co-adaptation of their attack and defense mechanisms. In this context, phages have evolved diverse anti-CRISPR proteins to evade the bacterial CRISPR–Cas immune system, and propagate. Anti-CRISPR proteins do not share much resemblance with each other and with proteins of known function, which raises intriguing questions particularly relating to their modes of action. In recent years, there have been many structure–function studies shedding light on different CRISPR–Cas inhibition strategies. As the anti-CRISPR field of research is rapidly growing, it is opportune to review the current knowledge on these proteins, with particular emphasis on the molecular strategies deployed to inactivate distinct steps of CRISPR–Cas immunity. Anti-CRISPR proteins can be orthosteric or allosteric inhibitors of CRISPR–Cas machineries, as well as enzymes that irreversibly modify CRISPR–Cas components. This repertoire of CRISPR–Cas inhibition mechanisms will likely expand in the future, providing fundamental knowledge on phage–bacteria interactions and offering great perspectives for the development of biotechnological tools to fine-tune CRISPR–Cas-based gene edition.

scholarly journals A Cognitive Computational Model Inspired by the Immune System Response

2014 ◽  
Vol 2014 ◽  
pp. 1-15
Author(s):  
Mohamed Abdo Abd Al-Hady ◽  
Amr Ahmed Badr ◽  
Mostafa Abd Al-Azim Mostafa
Keyword(s):  
Immune System ◽  
Computational Model ◽  
Cognitive Architecture ◽  
Intelligent Agent ◽  
System Response ◽  
Danger Theory ◽  
Proposed Model ◽  
Immune System Response ◽  
Fuzzy State

The immune system has a cognitive ability to differentiate between healthy and unhealthy cells. The immune system response (ISR) is stimulated by a disorder in the temporary fuzzy state that is oscillating between the healthy and unhealthy states. However, modeling the immune system is an enormous challenge; the paper introduces an extensive summary of how the immune system response functions, as an overview of a complex topic, to present the immune system as a cognitive intelligent agent. The homogeneity and perfection of the natural immune system have been always standing out as the sought-after model we attempted to imitate while building our proposed model of cognitive architecture. The paper divides the ISR into four logical phases: setting a computational architectural diagram for each phase, proceeding from functional perspectives (input, process, and output), and their consequences. The proposed architecture components are defined by matching biological operations with computational functions and hence with the framework of the paper. On the other hand, the architecture focuses on the interoperability of main theoretical immunological perspectives (classic, cognitive, and danger theory), as related to computer science terminologies. The paper presents a descriptive model of immune system, to figure out the nature of response, deemed to be intrinsic for building a hybrid computational model based on a cognitive intelligent agent perspective and inspired by the natural biology. To that end, this paper highlights the ISR phases as applied to a case study on hepatitis C virus, meanwhile illustrating our proposed architecture perspective.

scholarly journals A Case Study for a New Approach of a Constant Pressure Perfused Ex-Vivo Model of the Equine Larynx

2013 ◽  
Author(s):  
S. Otto ◽  
V. Tast ◽  
J. K. Michler ◽  
Ch. K. W. Mülling
Keyword(s):  
Constant Pressure ◽  
Ex Vivo ◽  
Ex Vivo Model ◽  
New Approach

Ancient microbial arms race sharpened our immune system—but also left us vulnerable

Science ◽  
2020 ◽  
Author(s):  
Ann Gibbons
Keyword(s):  
Immune System ◽  
Arms Race

Does Individual Health Have Implications for Individuals’ Attitudes towards Minority Groups? A Case Study from the Greek Population

2019 ◽  
Vol 32 (Special_Issue_1) ◽  
pp. i238-i252
Author(s):  
Jonathan Hall ◽  
Carolin Rapp ◽  
Terje Andreas Eikemo
Keyword(s):  
Immune System ◽  
Large Scale ◽  
Minority Groups ◽  
Racial Groups ◽  
Political Consequences ◽  
Individual Level ◽  
System Functioning ◽  
Moral Crisis ◽  
To Receive

Abstract Immunological defence against pathogens and behavioural responses to members of other ethnic or racial groups may be understood as co-evolved solutions to a commonly recurring adaptive problem in our ancestral environment: the need to avoid infectious disease. In recent years, research on the concept of the behavioural immune system has highlighted behavioural defence, showing in particular that individual-level disgust sensitively is associated with greater prejudice towards members of other—particularly stigmatized—social groups. Stigma thus represents in part a human disease-avoidance strategy. This mechanism is thereby assumed to be particularly strong for individuals who report poor mental and/or physical health. In this article, we draw upon MIGHEAL data to examine how health vulnerabilities impact prejudice towards new immigrants in Greece—a key refugee- and migrant-receiving society. The findings have direct implications for the political consequences of health interventions: policies that result in enhanced immune-system functioning and resilience to health shocks may reduce prejudice towards new migrants, enhancing a society’s capacity to receive and integrate refugees and other migrants. Health policy may thus provide an avenue by which societies improve their responses to large-scale migration flows—a policy area that arguably represents the greatest moral crisis of our time.

scholarly journals Herpes Simplex Virus Type 1 Interactions with the Interferon System

2020 ◽  
Vol 21 (14) ◽  
pp. 5150
Author(s):  
Kevin Danastas ◽  
Monica Miranda-Saksena ◽  
Anthony L. Cunningham
Keyword(s):  
Herpes Simplex Virus ◽  
Immune System ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Viral Pathogens ◽  
Interferon Stimulated Genes ◽  
Simplex Virus ◽  
Hsv 1

The interferon (IFN) system is one of the first lines of defense activated against invading viral pathogens. Upon secretion, IFNs activate a signaling cascade resulting in the production of several interferon stimulated genes (ISGs), which work to limit viral replication and establish an overall anti-viral state. Herpes simplex virus type 1 is a ubiquitous human pathogen that has evolved to downregulate the IFN response and establish lifelong latent infection in sensory neurons of the host. This review will focus on the mechanisms by which the host innate immune system detects invading HSV-1 virions, the subsequent IFN response generated to limit viral infection, and the evasion strategies developed by HSV-1 to evade the immune system and establish latency in the host.

HYPOPHILOSOPHY

2018 ◽  
Vol 35 (02) ◽  
pp. 138-157 ◽  
Author(s):  
Elijah Millgram
Keyword(s):  
Immune System ◽  
Machine Tool ◽  
Machine Tool Industry

Abstract:The more obvious forms of corruption are often preceded and explained by the etiolation of a practice: as its participants lose track of the point of their activities, their moral immune system is disabled. The argument is developed via a case study, philosophy itself. After advancing the hypothesis that philosophy is in the first instance the machine tool industry of the intellect—that its task is making the intellectual tools that make the intellectual tools—we consider what becomes of such an enterprise when this objective slips out of focus.

An evolutionary perspective on gastrointestinal nematodes of sheep

2011 ◽  
Vol 85 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M.J. Stear ◽  
D. Singleton ◽  
L. Matthews
Keyword(s):  
Immune System ◽  
Natural Selection ◽  
Fundamental Theorem ◽  
Domestic Animals ◽  
Gastrointestinal Nematodes ◽  
Arms Race ◽  
Evolutionary Perspective ◽  
Host Parasite Relationship ◽  
Parasite Relationship ◽  
Host Parasite

AbstractThe purpose of this paper was to discuss from an evolutionary perspective the interaction between domestic sheep (Ovis aries)and their gastrointestinal nematodes. Although evolution is the central theme of biology, there has been little attempt to consider how evolutionary forces have shaped and continue to shape the relationships between domestic animals and their parasite community. Mathematical modelling of the host–parasite relationship indicated that the system is remarkably robust to perturbations in its parameters. This robustness may be a consequence of the long coevolution of host and parasites. Although nematodes can potentially evolve faster than the host, coevolution is not dominated by the parasite and there are several examples where breeds of cattle or sheep have evolved high levels of resistance to disease. Coevolution is a more equal partnership between host and nematode than is commonly assumed. Coevolution between parasites and the host immune system is often described as an arms race where both host immune response genes and parasite proteins evolve rapidly in response to each other. However, initial results indicate that nematode antigens are not evolving rapidly; the arms race between the immune system and nematodes, if it exists, is happening very slowly. Fisher's fundamental theorem of natural selection states that genes with positive effects on fitness will be fixed by natural selection. Consequently, heritable variation in fitness traits is expected to be low. Contrary to this argument, there is considerable genetic variation in resistance to nematode infection. In particular, the heritabilities of nematode-specific IgA and IgE activity are moderate to high. The reasons for this apparent violation of the fundamental theorem of natural selection are not clear but several possible explanations are explored. Faecal nematode egg counts increase at the beginning of the grazing season – a phenomenon known as the periparturient rise. This increase benefits host and parasite and appears to be a consequence of coevolution. In conclusion, an evolutionary perspective can shed light on many aspects of the host–parasite relationship in domestic animals.

scholarly journals The Relationship between Infection-Avoidance Tendency and Exclusionary Attitudes towards Foreigners: A Case Study of the COVID-19 Outbreak in Japan

2020 ◽  
Author(s):  
Mei Yamagata ◽  
Tsukasa Teraguchi ◽  
Asako Miura
Keyword(s):  
Immune System ◽  
Individual Differences ◽  
Web Survey ◽  
Social Changes ◽  
Psychological States ◽  
Avoidance Tendency ◽  
System A ◽  
Preventive Actions ◽  
The Relationship

Amidst the worldwide outbreak of COVID-19 in January 2020, this study focused on the preventive behaviours against COVID-19 infection and the exclusionary attitude towards foreigners in Japan. Particularly, we examined the effects of individual differences in the infection-avoidance tendency based on the behavioural immune system. A web survey of 1,248 Japanese citizens aged 18 years or above living in Japan who were registrants of a crowdsourcing service indicated that as the threat of the COVID-19 spread increased, there were tendencies for infection-preventive behaviours to increase. In addition, people with a strong infection-avoidance tendency adopted more preventive actions, regardless of whether they were under normal circumstances or the threat of infection, indicating their strong rejective attitudes towards the Chinese and other foreigners under the threat of infection. This study recorded the behavioural and psychological states of people who were in the midst of rapid and unpredictable real-world changes in the early stages of the infection. Data collected in Japan, where the infection had begun earlier, will provide valuable knowledge to countries worldwide where major social changes are expected in the future.

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