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Nature Communications Jan 2023The ubiquitous pathogen Toxoplasma gondii has a complex lifestyle with different metabolic activities at different stages that are intimately linked to the parasitic...
The ubiquitous pathogen Toxoplasma gondii has a complex lifestyle with different metabolic activities at different stages that are intimately linked to the parasitic environments. Here we identified the eukaryotic regulator of cellular homeostasis AMP-activated protein kinase (AMPK) in Toxoplasma and discovered its role in metabolic programming during parasite's lytic cycle. The catalytic subunit AMPKα is quickly phosphorylated after the release of intracellular parasites to extracellular environments, driving energy-producing catabolism to power parasite motility and invasion into host cells. Once inside host cells, AMPKα phosphorylation is reduced to basal level to promote a balance between energy production and biomass synthesis, allowing robust parasite replication. AMPKγ depletion abolishes AMPKα phosphorylation and suppresses parasite growth, which can be partially rescued by overexpressing wildtype AMPKα but not the phosphorylation mutants. Thus, through the cyclic reprogramming by AMPK, the parasites' metabolic needs at each stage are satisfied and the lytic cycle progresses robustly.
Topics: Animals; Toxoplasma; AMP-Activated Protein Kinases; Parasites; Phosphorylation; Homeostasis
PubMed: 36702847
DOI: 10.1038/s41467-023-36084-0 -
The Journal of Parasitology Mar 2022Parasitic nematodes infect a variety of organisms including insects and vertebrates. To survive, they evade host immune responses to cause morbidity and mortality.... (Review)
Review
Parasitic nematodes infect a variety of organisms including insects and vertebrates. To survive, they evade host immune responses to cause morbidity and mortality. Despite the vast clinical knowledge regarding nematode infections and their biological makeup, molecular understanding of the interactions between host and parasite remains poorly understood. The utilization of model systems has thus been employed to help elucidate the molecular interactions of the host immune response during parasitic nematode infection. Using model systems, it has been well established that parasitic nematodes evade host immunity by releasing excretory/secretory proteins (ESPs), which are involved in immunomodulation. Model systems have enabled researchers to characterize further the underlying mechanisms ESPs use to facilitate evasion and modulation of the host immune response. This review assessed notable ESPs from parasitic nematodes that infect vertebrates or insects and have been studied in mechanistic detail. Being able to characterize how ESPs affect the immune systems of hosts on a molecular level increases our understanding of host-parasite interactions and could lead to the identification of novel therapeutic targets and important molecular pathways.
Topics: Animals; Host-Parasite Interactions; Immunity; Immunomodulation; Nematoda; Nematode Infections; Parasites
PubMed: 35435987
DOI: 10.1645/21-33 -
Parasitology Apr 2022Environmental stability can have profound impacts on life history trait evolution in organisms, especially with respect to development and reproduction. In theory,... (Review)
Review
Environmental stability can have profound impacts on life history trait evolution in organisms, especially with respect to development and reproduction. In theory, free-living species, when subjected to relatively stable and predictable conditions over many generations, should evolve narrow niche breadths and become more specialized. In parasitic organisms, this level of specialization is reflected by their host specificity. Here, we tested how host specificity impacts the reproductive strategies of parasites, a subject seldomly addressed for this group. Through an extensive review of the literature, we collated a worldwide dataset to predict, through Bayesian multilevel modelling, the effect of host specificity on the reproductive strategies of parasitic copepods of fishes or corals. We found that copepods of fishes with low host specificity (generalists) invest more into reproductive output with larger clutch sizes, whereas generalist copepods of corals invest less into reproductive output with smaller clutch sizes. The differences in host turnover rates through an evolutionary timescale could explain the contrasting strategies across species observed here, which should still favour the odds of parasites encountering and infecting a host. Ultimately, the differences found in this study reflect the unique evolutionary history that parasites share both intrinsically and extrinsically with their hosts.
Topics: Animals; Bayes Theorem; Host Specificity; Host-Parasite Interactions; Parasites; Reproduction; Species Specificity
PubMed: 35331349
DOI: 10.1017/S0031182021002122 -
Frontiers in Cellular and Infection... 2023
Topics: Animals; Humans; Systems Biology; Parasitic Diseases; Parasites
PubMed: 37124048
DOI: 10.3389/fcimb.2023.1192732 -
Trends in Parasitology Jul 2021Brood parasitism is the introduction of unrelated progeny into the nest or colony of a host that then raises the foreign young. This reproductive strategy has evolved... (Review)
Review
Brood parasitism is the introduction of unrelated progeny into the nest or colony of a host that then raises the foreign young. This reproductive strategy has evolved independently and repeatedly among diverse animal taxa, and brood parasite-host interactions have become models for understanding coevolutionary arms races. Yet brood parasites have remained largely overlooked in previous syntheses of natural enemy ecology. Here, we argue that brood parasites are a heterogeneous and versatile class of natural enemies, blending traits characteristic of predators and trophic parasites. The functional distinctness of brood parasites reinforces the idea that natural enemies exist along a continuum rather than as a dichotomy. Brood parasite-host interactions can serve as valuable case studies to unify parasite-host and predator-prey theories.
Topics: Animals; Biological Evolution; Host-Parasite Interactions; Parasites
PubMed: 33685784
DOI: 10.1016/j.pt.2021.02.005 -
Journal of Helminthology Jan 2023Reptiles, as well as other vertebrate groups, harbour a significant diversity of parasitic organisms, from nematodes and other helminths to viruses and bacteria. The... (Review)
Review
Reptiles, as well as other vertebrate groups, harbour a significant diversity of parasitic organisms, from nematodes and other helminths to viruses and bacteria. The Northeast is one of the richest regions in Brazil in terms of the reptile diversity, number of species and endemism. Parasites are diverse organisms and knowledge about the parasitic fauna of vertebrates is an important factor in understanding the ecological relationships between hosts and the environment. Studies on the parasitic fauna of reptiles in South America have increased in the past few years. The present review is a compilation of 122 studies published from 1924 to 2021. We present information on 101 species of reptiles from five groups (amphisbaenians, crocodile, testudines, snakes and lizards) and 183 parasitic taxa belonging to four phyla: Nematoda; Arthropoda; Platyhelminthes; and Acanthocephala. Nematodes were the most frequently recorded species. Lizards and snakes had more records of parasitism and higher levels of parasite richness and diversity. Ceará was the state with most studies and recorded cases of parasite-host association. The Caatinga and Atlantic Forest were the most investigated environments. The objective of this review was to contribute knowledge on the parasitic biodiversity in reptiles from Northeast Brazil, which may help identify gaps in our knowledge and guide future studies.
Topics: Animals; Parasites; Brazil; Checklist; Nematoda; Lizards; Snakes
PubMed: 36637249
DOI: 10.1017/S0022149X22000785 -
Biology of the Cell Jun 2020Gregarines, a polyphyletic group of apicomplexan parasites infecting mostly non-vertebrates hosts, remains poorly known at taxonomic, phylogenetic and genomic levels.... (Review)
Review
Gregarines, a polyphyletic group of apicomplexan parasites infecting mostly non-vertebrates hosts, remains poorly known at taxonomic, phylogenetic and genomic levels. However, it represents an essential group for understanding evolutionary history and adaptive capacities of apicomplexan parasites to the remarkable diversity of their hosts. Because they have a mostly extracellular lifestyle, gregarines have developed other cellular developmental forms and host-parasite interactions, compared with their much better studied apicomplexan cousins, intracellular parasites of vertebrates (Hemosporidia, Coccidia, Cryptosporidia). This review highlights the promises offered by the molecular exploration of gregarines, that have been until now left on the side of the road of the comparative -omic exploration of apicomplexan parasites. Elucidating molecular bases for both their ultrastructural, functional and behavioural similarities and differences, compared with those of the typical apicomplexan models, is expected to provide entirely novel clues on the adaptive capacities developed by Apicomplexa over evolution. A challenge remains to identify which gregarines should be explored in priority, as recent metadata from open and host-associated environments have confirmed how underestimated is our current view on true gregarine biodiversity. It is now time to turn to gregarines to widen the currently highly skewed view we have of adaptive mechanisms developed by Apicomplexa.
Topics: Animals; Apicomplexa; Biodiversity; Genomics; Metadata; Parasites; Phylogeny
PubMed: 32176937
DOI: 10.1111/boc.202000006 -
International Journal For Parasitology Dec 2021In the five decades since the first publication of the International Journal for Parasitology, ecological parasitology has grown from modest beginnings to become a... (Review)
Review
In the five decades since the first publication of the International Journal for Parasitology, ecological parasitology has grown from modest beginnings to become a modern discipline with a strong theoretical foundation, a diverse toolkit, and a multidisciplinary approach. In this review, I highlight 12 advances in the field that have spurred its growth over the past 50 years. Where relevant, I identify pivotal contributions that have altered the course of research, as well as the influence of developments in other fields such as mainstream ecology and molecular biology. The 12 key advances discussed are in areas including parasite population dynamics and community assembly, the regulation of host population abundance and food web structure, parasites as agents of natural selection, the impacts of biodiversity and anthropogenic changes on host-parasite interactions, the biogeography of parasite diversity, and the evolutionary genetics of parasites. I conclude by identifying some challenges and opportunities lying ahead, which need to be met for the future growth of ecological research on host-parasite interactions.
Topics: Animals; Biodiversity; Biological Evolution; Host-Parasite Interactions; Parasites; Parasitology
PubMed: 34390744
DOI: 10.1016/j.ijpara.2021.07.001 -
Journal of Theoretical Biology Oct 2021Although mortality increases with age in most organisms, senescence is missing from models of parasite evolution. Since virulence evolves according to the host's...
Although mortality increases with age in most organisms, senescence is missing from models of parasite evolution. Since virulence evolves according to the host's mortality, and since virulence influences the intensity of transmission, which determines the average age at infection and thus the mortality rate of a senescing host, we expected that epi-evolutionary feedbacks would underlie the evolution of virulence in a population of senescing hosts. We tested this idea by extending an age-structured model of epidemiological dynamics with the parasite's evolution. A straightforward prediction of our model is that stronger senescence forces the evolution of higher virulence. However, the model also reveals that the evolved virulence depends on the average age at infection, giving an evolutionary feedback with the epidemiological situation, a prediction not found when assuming a constant mortality rate with age. Additionally, and in contrast to most models of parasite evolution, we found that the virulence at the evolutionary equilibrium is influenced by whether the force of infection depends on the density or on the frequency of infected hosts, due to changes in the average age at infection. Our findings suggest that ignoring age-specific effects, and in particular senescence, can give misleading predictions about parasite evolution.
Topics: Animals; Biological Evolution; Host-Parasite Interactions; Models, Biological; Parasites; Virulence
PubMed: 33915143
DOI: 10.1016/j.jtbi.2021.110732 -
Environmental Microbiology Dec 2023Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and...
Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and possibly even control, species interactions like host-parasite relationships. Yet, while studies have investigated host-parasites and microbiomes separately, little has been done to understand all three groups synergistically. Here, we collected infected and uninfected Eurypanopeus depressus crab hosts from a coastal North Carolina oyster reef three times over 4 months. Infected crabs demonstrated an external stage of the rhizocephalan parasite, Loxothylacus panopaei. Community analyses revealed that microbial richness and diversity were significantly different among tissue types (uninfected crab, infected crab, parasite externae and parasite larvae) and over time (summer and fall). Specifically, the microbial communities from parasite externae and larvae had similar microbiomes that were consistent through time. Infected crabs demonstrated microbial communities spanning those of their host and parasite, while uninfected crabs showed more distinctive communities with greater variability over time. Microbial communities were also found to be indicators of early-stage infections. Resolving the microbial community composition of a host and its parasite is an important step in understanding the microbiome's role in the host-parasite relationship and determining how this tripartite relationship impacts coevolutionary processes.
Topics: Animals; Parasites; Host-Parasite Interactions; Brachyura; Parasitic Diseases; Microbiota
PubMed: 37918974
DOI: 10.1111/1462-2920.16533