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

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.

2018 ◽  
Author(s):  
Frida Ben-Ami ◽  
Christian Orlic ◽  
Roland R. Regoes

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.


Parasitology ◽  
2013 ◽  
Vol 141 (4) ◽  
pp. 475-481 ◽  
Author(s):  
TAMARA GÓMEZ-MORACHO ◽  
XULIO MASIDE ◽  
RAQUEL MARTÍN-HERNÁNDEZ ◽  
MARIANO HIGES ◽  
CAROLINA BARTOLOMÉ

SUMMARYNosema ceranaeis a widespread honeybee parasite, considered to be one of the pathogens involved in the colony losses phenomenon. To date, little is known about its intraspecific genetic variability. The few studies onN. ceranaevariation have focused on the subunits of ribosomal DNA, which are not ideal for this purpose and have limited resolution. Here we characterized three single copy loci (Actin, Hsp70andRPB1) in threeN. ceranaeisolates from Hungary and Hawaii. Our results provide evidence of unexpectedly high levels of intraspecific polymorphism, the coexistence of a wide variety of haplotypes within each bee colony, and the occurrence of genetic recombination inRPB1. Most haplotypes are not shared across isolates and derive from a few frequent haplotypes by a reduced number of singletons (mutations that appear usually just once in the sample), which suggest that they have a fairly recent origin. Overall, our data indicate that this pathogen has experienced a recent population expansion. The presence of multiple haplotypes within individual isolates could be explained by the existence of different strains ofN. ceranaeinfecting honeybee colonies in the field which complicates, and must not be overlooked, further analysis of host–parasite interactions.


2015 ◽  
Vol 23 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Imre Sándor Piross ◽  
Péter Fehérvári ◽  
Zoltán Vas ◽  
Szabolcs Solt ◽  
Éva Horváth ◽  
...  

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.


2013 ◽  
Vol 368 (1626) ◽  
pp. 20120503 ◽  
Author(s):  
Adam Lee ◽  
Alison Nolan ◽  
Jason Watson ◽  
Michael Tristem

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.


2018 ◽  
Vol 14 (4) ◽  
pp. 20170761 ◽  
Author(s):  
Adele Bordoni ◽  
Leonardo Dapporto ◽  
Irene Tatini ◽  
Martina Celli ◽  
Manuel Bercigli ◽  
...  

Trans-generational immunization is defined as the transmission of an enhanced resistance to a pathogen from parents to offspring. By using the host–parasite system of the ant Crematogaster scutellaris and the entomopathogenic fungus Metarhizium anisopliae , we describe this phenomenon for the first time in ants. We exposed four groups of hibernating queens to different treatments (i) a non-lethal dose of live conidiospores in Triton, (ii) a dose of heat-killed conidiospores in Triton, (iii) a control Triton solution, and (iv) a naive control. We exposed their first workers to a high dose of conidiospores and measured mortality rates . Workers produced by queens exposed to live conidiospores survived longer than those belonging to the other groups, while exposure to Triton and dead spores had no effect. Starved workers showed a significantly higher mortality. The treatments did not influence queen mortality, nor the number of offspring they produced at the emergence of the first worker, showing no evidence of immunization costs—at least for these parameters in the first year of colony development. We propose that trans-generational immunization represents an important component of social immunity that could affect colony success, particularly during the critical phase of claustral foundation.


2017 ◽  
Vol 284 (1866) ◽  
pp. 20171615 ◽  
Author(s):  
Alex Best ◽  
Ben Ashby ◽  
Andy White ◽  
Roger Bowers ◽  
Angus Buckling ◽  
...  

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.


2018 ◽  
Author(s):  
Megan Hahn ◽  
Nolwenn Dheilly

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.


2021 ◽  
Author(s):  
Lei Han ◽  
Tianming Lan ◽  
Yaxian Lu ◽  
Mengchao Zhou ◽  
Haimeng Li ◽  
...  

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.


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