scholarly journals Identification of an ancient endogenous retrovirus, predating the divergence of the placental mammals

2013 ◽  
Vol 368 (1626) ◽  
pp. 20120503 ◽  
Author(s):  
Adam Lee ◽  
Alison Nolan ◽  
Jason Watson ◽  
Michael Tristem
Keyword(s):  
Rapid Evolution ◽  
Endogenous Retrovirus ◽  
Arms Race ◽  
Endogenous Retroviruses ◽  
Selfish Genetic Elements ◽  
Host Parasite Interactions ◽  
Combined Use ◽  
Minimum Age ◽  
Host Parasite ◽  
First Time

The evolutionary arms race between mammals and retroviruses has long been recognized as one of the oldest host–parasite interactions. Rapid evolution rates in exogenous retroviruses have often made accurate viral age estimations highly problematic. Endogenous retroviruses (ERVs), however, integrate into the germline of their hosts, and are subjected to their evolutionary rates. This study describes, for the first time, a retroviral orthologue predating the divergence of placental mammals, giving it a minimum age of 104–110 Myr. Simultaneously, other orthologous selfish genetic elements (SGEs), inserted into the ERV sequence, provide evidence for the oldest individual mammalian-wide interspersed repeat and medium-reiteration frequency interspersed repeat mammalian repeats, with the same minimum age. The combined use of shared SGEs and reconstruction of viral orthologies defines new limits and increases maximum ‘lookback’ times, with subsequent implications for the field of paleovirology.

scholarly journals Equus roundworms (Parascaris univalens) are undergoing rapid divergence due to host and environment factors

2021 ◽  
Author(s):  
Lei Han ◽  
Tianming Lan ◽  
Yaxian Lu ◽  
Mengchao Zhou ◽  
Haimeng Li ◽  
...  
Keyword(s):  
Positive Selection ◽  
Rapid Evolution ◽  
Host Parasite Interactions ◽  
Drug History ◽  
Rapid Divergence ◽  
Evolution Of Metabolism ◽  
Genetic Level ◽  
Different Populations ◽  
Host Parasite ◽  
First Time

Abstract Background The evolution of parasites is often directly affected by the host's environment. Studies on the evolution of the same parasites in different hosts are extremely attractive and highly relevant to our understanding of divergence and speciation. Methods Here we performed whole genome sequencing of Parascaris univalens from different Equus hosts (horses, zebras and donkeys). Phylogenetic and selection analysis was performed to study the divergence and adaptability of P. univalens. Results At the genetic level, multiple lines of evidence support that P. univalens were mainly separated into two clades (Horse-derived and Zebra & Donkey-derived). This divergence began at 300-1000 years ago, and we found that most of the key enzymes related to glycolysis were under strong positive selection in zebra & donkey-derived roundworms, but lipid related metabolism system was under positive selection in the horse-derived roundworms, indicating that the adaptive evolution of metabolism may drive the divergence in past few centuries. In addition, we found that some drug-related genes have a significantly higher degree of selection in different populations. Conclusions This work reports evidence that the host’s diet drives the divergence of roundworms for the first time, and also supports that divergence is a continuous and dynamic process, and continuous monitoring of the effects of differences in nutritional and drug history on rapid evolution of roundworms are conducive to further understanding host-parasite interactions.

scholarly journals Disentangling non-specific and specific transgenerational immune priming components in host–parasite interactions

2020 ◽  
Vol 287 (1920) ◽  
pp. 20192386
Author(s):  
Frida Ben-Ami ◽  
Christian Orlic ◽  
Roland R. Regoes
Keyword(s):  
Genetic Epidemiology ◽  
Ecological Systems ◽  
High Dose ◽  
Immune Priming ◽  
Specific Effects ◽  
Host Parasite Interactions ◽  
Pasteuria Ramosa ◽  
Different Strains ◽  
Host Parasite ◽  
First Time

Exposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be non-specific or specific, and has been found to extend across generations. Disentangling and quantifying specific and non-specific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modelling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa . In the experiment, we exposed hosts to a high dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same (homologous) or a different (heterologous) strain. We find that exposure of Daphnia to Pasteuria decreases the susceptibility of their offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Methodologically, our work represents an important contribution not only to the analysis of immune priming in ecological systems but also to the experimental assessment of vaccines. We present, for the first time, an inference framework to investigate specific and non-specific effects of immune priming on the susceptibility distribution of hosts—effects that are central to understanding immunity and the effect of vaccines.

scholarly journals Disentangling unspecific and specific transgenerational immune priming components in host-parasite interactions

2018 ◽  
Author(s):  
Frida Ben-Ami ◽  
Christian Orlic ◽  
Roland R. Regoes
Keyword(s):  
Bacterial Pathogen ◽  
Immune Memory ◽  
High Dose ◽  
Immune Priming ◽  
Host Parasite Interactions ◽  
Pasteuria Ramosa ◽  
Wide Range ◽  
Different Strains ◽  
Host Parasite ◽  
First Time

AbstractExposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be unspecific or specific, and has been found to extend across generations. Disentangling and quantifying specific and unspecific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modeling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa. In the experiments, we exposed hosts to a high-dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same or a different strain, i. e. homologously or heterogously. We find that exposure to Pasteuria decreases the susceptibility of a host’s offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Our work represents an important contribution not only to the analysis of immune priming in ecological systems, but also to the experimental assessment of vaccines. We present for the first time an inference framework to investigate specific and unspecific effects of immune priming on the susceptibility distribution of hosts — effects that are central to understanding immunity and the effect of vaccines.Author summaryImmune memory is a feature of immune systems that forms the basis of vaccination. In opposition to textbook accounts, the ability to specifically remember previous exposures has been found to extend to invertebrates and shown to be able to be passed on from mother to off-spring, i. e. to be transgenerational. In this paper, we investigate the extent of this specificity in unprecedented detail in water fleas. We exposed water flea mothers to different strains of a bacterial pathogen and challenged their offspring with a wide range of doses of a strain that were either identical to (homologous) or different from (heterologous) the strain, to which the mother had been exposed. We find that, while exposure of the mother reduces the susceptibility of the offspring, this effect is not specific. This work outlines the limits of specific transgenerational immune memory in this invertebrate system.

scholarly journals Louse (Insecta: Phthiraptera) infestations of the Amur Falcon (Falco amurensis) and the Red-footed Falcon

2015 ◽  
Vol 23 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Imre Sándor Piross ◽  
Péter Fehérvári ◽  
Zoltán Vas ◽  
Szabolcs Solt ◽  
Éva Horváth ◽  
...  
Keyword(s):  
South Africa ◽  
Life History ◽  
Host Species ◽  
Life History Traits ◽  
Population Parameters ◽  
Model Species ◽  
Host Parasite Interactions ◽  
Louse Species ◽  
Host Parasite ◽  
First Time

Abstract Little is known about the louse species harboured by Red-footed and Amur Falcons despite the fact that various life-history traits of these hosts make them good model species to study host-parasite interactions. We collected lice samples from fully grown Amur (n=20) and Red-footed Falcons (n=59), and from nestlings of Red-footed Falcons (n=179) in four countries: Hungary, India, Italy and South Africa. We identified 3 louse species on both host species, namely Degeeriella rufa, Colpocephalum subzerafae and Laembothrion tinnunculi. The latter species has never been found on these hosts. Comparing population parameters of lice between hosts we found significantly higher prevalence levels of D. rufa and C. subzerafae on Amur Falcons. Adult Red-footed Falcons had higher D. rufa prevalence compared to C. subzerafae. For the first time we also show inter-annual shift in prevalence and intensity levels of these species on Red-footed Falcons; in 2012 on adult hosts C. subzerafae had higher intensity levels than D. rufa, however in 2014 D. rufa had significantly higher intensity compared to C. subzerafae. In case of nestlings both louse species had significantly higher preva lence levels than in 2014. The exact causes of such inter-annual shifts are yet to be understood.

scholarly journals What Can Phages Tell Us about Host-Pathogen Coevolution?

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
John J. Dennehy
Keyword(s):  
Experimental Studies ◽  
Arms Race ◽  
Gene Model ◽  
Genetic Population ◽  
Life History Data ◽  
Heterogeneous Landscape ◽  
Host Parasite Interactions ◽  
In The Wild ◽  
Host Parasite ◽  
Abiotic Interactions

The outcomes of host-parasite interactions depend on the coevolutionary forces acting upon them, but because every host-parasite relation is enmeshed in a web of biotic and abiotic interactions across a heterogeneous landscape, host-parasite coevolution has proven difficult to study. Simple laboratory phage-bacteria microcosms can ameliorate this difficulty by allowing controlled, well-replicated experiments with a limited number of interactors. Genetic, population, and life history data obtained from these studies permit a closer examination of the fundamental correlates of host-parasite coevolution. In this paper, I describe the results of phage-bacteria coevolutionary studies and their implications for the study of host-parasite coevolution. Recent experimental studies have confirmed phage-host coevolutionary dynamics in the laboratory and have shown that coevolution can increase parasite virulence, specialization, adaptation, and diversity. Genetically, coevolution frequently proceeds in a manner best described by the Gene for Gene model, typified by arms race dynamics, but certain contexts can result in Red Queen dynamics according to the Matching Alleles model. Although some features appear to apply only to phage-bacteria systems, other results are broadly generalizable and apply to all instances of antagonistic coevolution. With laboratory host-parasite coevolutionary studies, we can better understand the perplexing array of interactions that characterize organismal diversity in the wild.

scholarly journals Reconstitution of the Ancestral Glycoprotein of Human Endogenous Retrovirus K and Modulation of Its Functional Activity by Truncation of the Cytoplasmic Domain

2009 ◽  
Vol 83 (24) ◽  
pp. 12790-12800 ◽  
Author(s):  
Kirsten Hanke ◽  
Philipp Kramer ◽  
Sandra Seeher ◽  
Nadine Beimforde ◽  
Reinhard Kurth ◽  
...  
Keyword(s):  
Intracellular Trafficking ◽  
Mammalian Cells ◽  
Endogenous Retrovirus ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retrovirus ◽  
Back Mutation ◽  
Genes Encoding ◽  
Carboxy Terminal ◽  
Processing Stability ◽  
First Time

ABSTRACT Endogenous retroviruses present in the human genome provide a rich record of ancient infections. All presently recognized elements, including the youngest and most intact proviruses of the human endogenous retrovirus K(HML-2) [HERV-K(HML-2)] family, have suffered postinsertional mutations during their time of chromosomal residence, and genes encoding the envelope glycoprotein (Env) have not been spared these mutations. In this study, we have, for the first time, reconstituted an authentic Env of a HERV-K(HML-2) provirus by back mutation of putative postinsertional amino acid changes of the protein encoded by HERV-K113. Aided by codon-optimized expression, we demonstrate that the reconstituted Env regained its ability to be incorporated into retroviral particles and to mediate entry. The original ancient HERV-K113 Env was synthesized as a moderately glycosylated gp95 precursor protein cleaved into surface and transmembrane (TM) subunits. Of the nine N-linked oligosaccharides, four are part of the TM subunit, contributing 15 kDa to its apparent molecular mass of 41 kDa. The carbohydrates, as well as the cytoplasmic tail, are critical for efficient intracellular trafficking, processing, stability, and particle incorporation. Whereas deletions of the carboxy-terminal 6 residues completely abrogated cleavage and virion association, more extensive truncations slightly enhanced incorporation but dramatically increased the ability to mediate entry of pseudotyped lentiviruses. Although the first HERV-K(HML-2) elements infected human ancestors about 30 million years ago, our findings indicate that their glycoproteins are in most respects remarkably similar to those of classical contemporary retroviruses and can still mediate efficient entry into mammalian cells.

scholarly journals Nutrient stoichiometry shapes microbial coevolution

2017 ◽  
Author(s):  
Megan L. Larsen ◽  
Steven W. Wilhelm ◽  
Jay T. Lennon
Keyword(s):  
Arms Race ◽  
Lytic Phage ◽  
Nutrient Stoichiometry ◽  
P Limitation ◽  
Host Parasite Interactions ◽  
Negative Frequency Dependent Selection ◽  
Selection For ◽  
The Stability ◽  
Host Parasite

ABSTRACTCoevolution is a force contributing to the generation and maintenance of biodiversity. It is influenced by environmental conditions including the scarcity of essential resources, which can drive the evolution of defense and virulence traits. We conducted a long-term chemostat experiment where the marine cyanobacterium Synechococcus was challenged with a lytic phage under nitrogen (N) or phosphorus (P) limitation. This manipulation of nutrient stoichiometry altered the stability of host-parasite interactions and the underlying mode of coevolution. By assessing infectivity with >18,000 pairwise challenges, we documented directional selection for increased phage resistance, consistent with arms-race dynamics while phage infectivity fluctuated through time, as expected when coevolution is driven by negative frequency-dependent selection. The resulting infection networks were 50 % less modular under N-versus P-limitation reflecting host-range contraction and asymmetric coevolutionary trajectories. Nutrient stoichiometry affects eco-evolutionary feedbacks in ways that may alter the dynamics and functioning of environmental and host-associated microbial communities.

Living with Two Genomes: Grafting and Its Implications for Plant Genome-to-Genome Interactions, Phenotypic Variation, and Evolution

2019 ◽  
Vol 53 (1) ◽  
pp. 195-215 ◽  
Author(s):  
Brandon S. Gaut ◽  
Allison J. Miller ◽  
Danelle K. Seymour
Keyword(s):  
Host Resistance ◽  
Arms Race ◽  
Plant Genome ◽  
Long Term Effects ◽  
Evolutionary Innovation ◽  
Host Parasite Interactions ◽  
Artificial Grafts ◽  
Genome Interactions ◽  
Host Parasite

Plant genomes interact when genetically distinct individuals join, or are joined, together. Individuals can fuse in three contexts: artificial grafts, natural grafts, and host–parasite interactions. Artificial grafts have been studied for decades and are important platforms for studying the movement of RNA, DNA, and protein. Yet several mysteries about artificial grafts remain, including the factors that contribute to graft incompatibility, the prevalence of genetic and epigenetic modifications caused by exchanges between graft partners, and the long-term effects of these modifications on phenotype. Host–parasite interactions also lead to the exchange of materials, and RNA exchange actively contributes to an ongoing arms race between parasite virulence and host resistance. Little is known about natural grafts except that they can be frequent and may provide opportunities for evolutionary innovation through genome exchange. In this review, we survey our current understanding about these three mechanisms of contact, the genomic interactions that result, and the potential evolutionary implications.

scholarly journals Host–parasite fluctuating selection in the absence of specificity

2017 ◽  
Vol 284 (1866) ◽  
pp. 20171615 ◽  
Author(s):  
Alex Best ◽  
Ben Ashby ◽  
Andy White ◽  
Roger Bowers ◽  
Angus Buckling ◽  
...  
Keyword(s):  
Life History ◽  
Fluctuating Selection ◽  
Specific Host ◽  
Host Parasite Interactions ◽  
Stochastic Fluctuations ◽  
Selection Dynamics ◽  
Ecological Feedbacks ◽  
Host Life ◽  
Host Parasite ◽  
First Time

Fluctuating selection driven by coevolution between hosts and parasites is important for the generation of host and parasite diversity across space and time. Theory has focused primarily on infection genetics, with highly specific ‘matching-allele’ frameworks more likely to generate fluctuating selection dynamics (FSD) than ‘gene-for-gene’ (generalist–specialist) frameworks. However, the environment, ecological feedbacks and life-history characteristics may all play a role in determining when FSD occurs. Here, we develop eco-evolutionary models with explicit ecological dynamics to explore the ecological, epidemiological and host life-history drivers of FSD. Our key result is to demonstrate for the first time, to our knowledge, that specificity between hosts and parasites is not required to generate FSD. Furthermore, highly specific host–parasite interactions produce unstable, less robust stochastic fluctuations in contrast to interactions that lack specificity altogether or those that vary from generalist to specialist, which produce predictable limit cycles. Given the ubiquity of ecological feedbacks and the variation in the nature of specificity in host–parasite interactions, our work emphasizes the underestimated potential for host–parasite coevolution to generate fluctuating selection.

scholarly journals Not so sterile after all: The endomicrobiome of plerocercoids of the cestode parasiteSchistocephalus solidusand changes to the microbiome of its Threespine Stickleback host

2018 ◽  
Author(s):  
Megan Hahn ◽  
Nolwenn Dheilly
Keyword(s):  
Horizontal Transmission ◽  
Body Cavity ◽  
The Body ◽  
Schistocephalus Solidus ◽  
Host Parasite Interactions ◽  
Host Parasite ◽  
First Time ◽  
Host Tissues

AbstractDespite the growing recognition of the role of bacteria in animal biology, the microbiome of parasites remains largely unexplored. In particular, the presence of bacteria in tapeworms has never been investigated and parasites that exit the intestine would be considered sterile. We characterized for the first time the microbiome of a tapeworm.Schistocephalus solidusplerocercoids, collected from the body cavity of its stickleback host, were found to harbor a complex microbiome. The most abundant and the most prevalent bacteria wasPolynucleobacter sp.. In addition,S. solidusinfection was associated significant changes in the stickleback host gut microbiome with an increase in microbial load and changes in diversity and composition. Finally, the same bacteria were often found inS. solidusand the stomach and intestine of the corresponding hosts, a result that highlights the importance of characterizing the microbiome of host tissues and parasites from the same individuals to assess the potential for horizontal transmission of microbes. This study clearly emphasizes the need for further characterization of the microbiome of a broad range of parasites and for studies to determine the ecological, evolutionary and functional role that microbes play in host-parasite interactions.

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