scholarly journals Quality and quantity: transitions in antimicrobial gland use for parasite defense

2015 ◽  
Vol 5 (24) ◽  
pp. 5857-5868 ◽  
Author(s):  
Christopher Tranter ◽  
Hermógenes Fernández-Marín ◽  
William O. H. Hughes
Keyword(s):  
Parasite Defense

Resistance to Influence

2016 ◽  
Author(s):  
Brad J. Sagarin ◽  
Mary Lynn Miller Henningsen
Keyword(s):  
Negative Affect ◽  
Social Influence ◽  
Social Engineering ◽  
Third Party ◽  
Mechanisms Of Resistance ◽  
Potential Source ◽  
Stealing Thunder ◽  
Manipulative Intent ◽  
The Impact ◽  
Parasite Defense

This chapter reviews research on resistance to influence, active or passive processes that reduce the impact of a potential source of social influence. This chapter begins with a discussion of the antecedents of resistance: characteristics of the influence target (strong attitudes, demographics, and personality), perceived aspects of the influence attempt (manipulative intent, threats to freedoms), or counterinfluence messages from a third party (forewarning, inoculation, stealing thunder, the poison parasite defense, resistance to social engineering) that motivate resistance. The chapter proceeds to a discussion of internal mechanisms of resistance (counterarguing, bolstering initial attitudes, derogating the source, attributing negative affect to the message or source, attempting to correct for bias) and external mechanisms of resistance (interpersonal strategies of communicating resistance and issuing refusals) and concludes with a discussion of the consequences of resistance for attitudes and relationships.

Contagious itch and disgust during a lecture on ectoparasitic infestations: Two co‐activated complementary parasite defense systems?

2020 ◽  
Vol 33 (6) ◽  
Author(s):  
Marise S. Kamber ◽  
Mia Sutter ◽  
Alexander Navarini ◽  
Simon M. Mueller
Keyword(s):  
Defense Systems ◽  
Parasite Defense

scholarly journals Disentangling the effects of selection and loss bias on gene dynamics

2017 ◽  
Author(s):  
Jaime Iranzo ◽  
José A. Cuesta ◽  
Susanna Manrubia ◽  
Mikhail I. Katsnelson ◽  
Eugene V. Koonin
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genome Size ◽  
Mobile Genetic Elements ◽  
Loss Ratio ◽  
Effective Population ◽  
Strong Selection ◽  
Genetic Elements ◽  
Defense Systems ◽  
Parasite Defense

ABSTRACTWe combine mathematical modelling of genome evolution with comparative analysis of prokaryotic genomes to estimate the relative contributions of selection and intrinsic loss bias to the evolution of different functional classes of genes and mobile genetic elements (MGE). An exact solution for the dynamics of gene family size was obtained under a linear duplication-transfer-loss model with selection. With the exception of genes involved in information processing, particularly translation, which are maintained by strong selection, the average selection coefficient for most non-parasitic genes is low albeit positive, compatible with the observed positive correlation between genome size and effective population size. Free-living microbes evolve under stronger selection for gene retention than parasites. Different classes of MGE show a broad range of fitness effects, from the nearly neutral transposons to prophages, which are actively eliminated by selection. Genes involved in anti-parasite defense, on average, incur a fitness cost to the host that is at least as high as the cost of plasmids. This cost is probably due to the adverse effects of autoimmunity and curtailment of horizontal gene transfer caused by the defense systems and selfish behavior of some of these systems, such as toxin-antitoxin and restriction-modification modules. Transposons follow a biphasic dynamics, with bursts of gene proliferation followed by decay in the copy number that is quantitatively captured by the model. The horizontal gene transfer to loss ratio, but not the duplication to loss ratio, correlates with genome size, potentially explaining the increased abundance of neutral and costly elements in larger genomes.SIGNIFICANCEEvolution of microbes is dominated by horizontal gene transfer and the incessant host-parasite arms race that promotes the evolution of diverse anti-parasite defense systems. The evolutionary factors governing these processes are complex and difficult to disentangle but the rapidly growing genome databases provide ample material for testing evolutionary models. Rigorous mathematical modeling of evolutionary processes, combined with computer simulation and comparative genomics, allowed us to elucidate the evolutionary regimes of different classes of microbial genes. Only genes involved in key informational and metabolic pathways are subject to strong selection whereas most of the others are effectively neutral or even burdensome. Mobile genetic elements and defense systems are costly, supporting the understanding that their evolution is governed by the same factors.

Life: Molting as parasite defense

Science News ◽  
2012 ◽  
Vol 181 (10) ◽  
pp. 8-8
Author(s):  
Devin Powell
Keyword(s):  
Parasite Defense

scholarly journals Schistosome serine protease inhibitors: parasite defense or homeostasis?

2011 ◽  
Vol 83 (2) ◽  
pp. 663-672 ◽  
Author(s):  
Landys A. Lopez Quezada ◽  
James H McKerrow
Keyword(s):  
Phylogenetic Analysis ◽  
Schistosoma Mansoni ◽  
Serine Protease ◽  
Protease Inhibitors ◽  
Schistosoma Japonicum ◽  
Translational Regulation ◽  
Defense Mechanisms ◽  
Human Host ◽  
Reactive Center ◽  
Parasite Defense

Serpins are a structurally conserved family of macromolecular inhibitors found in numerous biological systems. The completion and annotation of the genomes of Schistosoma mansoni and Schistosoma japonicum has enabled the identification by phylogenetic analysis of two major serpin clades. S. mansoni shows a greater multiplicity of serpin genes, perhaps reflecting adaptation to infection of a human host. Putative targets of schistosome serpins can be predicted from the sequence of the reactive center loop (RCL). Schistosome serpins may play important roles in both post-translational regulation of schistosome-derived proteases, as well as parasite defense mechanisms against the action of host proteases.

Genetic diversity and parasite defense in a fragmented urban metapopulation of earthworms

2007 ◽  
Vol 10 (2) ◽  
pp. 162-175 ◽  
Author(s):  
S. G. Field ◽  
M. Lange ◽  
H. Schulenburg ◽  
T. P. Velavan ◽  
N. K. Michiels
Keyword(s):  
Genetic Diversity ◽  
Parasite Defense

Parasite defense mechanisms for evasion of host attack; A review

1987 ◽  
Vol 25 (2) ◽  
pp. 147-162 ◽  
Author(s):  
R. Wes Leid ◽  
C.M. Suquet ◽  
L. Tanigoshi
Keyword(s):  
Defense Mechanisms ◽  
Parasite Defense
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