-
Scientific Reports Nov 2023Microturbellarians are abundant and ubiquitous members of marine meiofaunal communities around the world. Because of their small body size, these microscopic animals are...
Microturbellarians are abundant and ubiquitous members of marine meiofaunal communities around the world. Because of their small body size, these microscopic animals are rarely considered as hosts for parasitic organisms. Indeed, many protists, both free-living and parasitic ones, equal or surpass meiofaunal animals in size. Despite several anecdotal records of "gregarines", "sporozoans", and "apicomplexans" parasitizing microturbellarians in the literature-some of them dating back to the nineteenth century-these single-celled parasites have never been identified and characterized. More recently, the sequencing of eukaryotic microbiomes in microscopic invertebrates have revealed a hidden diversity of protist parasites infecting microturbellarians and other meiofaunal animals. Here we show that apicomplexans isolated from twelve taxonomically diverse rhabdocoel taxa and one species of proseriate collected in four geographically distinct areas around the Pacific Ocean (Okinawa, Hokkaido, and British Columbia) and the Caribbean Sea (Curaçao) all belong to the apicomplexan genus Rhytidocystis. Based on comprehensive molecular phylogenies of Rhabdocoela and Proseriata inferred from both 18S and 28S rDNA sequences, as well as a molecular phylogeny of Marosporida inferred from 18S rDNA sequences, we determine the phylogenetic positions of the microturbellarian hosts and their parasites. Multiple lines of evidence, including morphological and molecular data, show that at least nine new species of Rhytidocystis infect the microturbellarian hosts collected in this study, more than doubling the number of previously recognized species of Rhytidocystis, all of which infect polychaete hosts. A cophylogenetic analysis examining patterns of phylosymbiosis between hosts and parasites suggests a complex picture of overall incongruence between host and parasite phylogenies, and varying degrees of geographic signals and taxon specificity.
Topics: Animals; Platyhelminths; Phylogeny; Parasites; DNA, Ribosomal; Apicomplexa
PubMed: 38030717
DOI: 10.1038/s41598-023-48233-y -
Trends in Parasitology Oct 2015Extracellular vesicles (EVs) have emerged as a ubiquitous mechanism for transferring information between cells and organisms across all three kingdoms of life. In... (Review)
Review
Extracellular vesicles (EVs) have emerged as a ubiquitous mechanism for transferring information between cells and organisms across all three kingdoms of life. In addition to their roles in normal physiology, vesicles also transport molecules from pathogens to hosts and can spread antigens as well as infectious agents. Although initially described in the host-pathogen context for their functions in immune surveillance, vesicles enable multiple modes of communication by, and between, parasites. Here we review the literature demonstrating that EVs are secreted by intracellular and extracellular eukaryotic parasites, as well as their hosts, and detail the functional properties of these vesicles in maturation, pathogenicity and survival. We further describe the prospects for targeting or exploiting these complexes in therapeutic and vaccine strategies.
Topics: Animals; Cell Communication; Exosomes; Extracellular Vesicles; Host-Parasite Interactions; Humans; Parasites; Parasitic Diseases
PubMed: 26433251
DOI: 10.1016/j.pt.2015.06.009 -
Antioxidants & Redox Signaling Aug 2012The cysteine (Cys) residues of proteins play two fundamentally important roles. They serve as sites of post-translational redox modifications as well as influence the... (Review)
Review
SIGNIFICANCE
The cysteine (Cys) residues of proteins play two fundamentally important roles. They serve as sites of post-translational redox modifications as well as influence the conformation of the protein through the formation of disulfide bonds.
RECENT ADVANCES
Redox-related and redox-associated protein folding in protozoan parasites has been found to be a major mode of regulation, affecting myriad aspects of the parasitic life cycle, host-parasite interactions, and the disease pathology. Available genome sequences of various parasites have begun to complement the classical biochemical and enzymological studies of these processes. In this article, we summarize the reversible Cys disulfide (S-S) bond formation in various classes of strategically important parasitic proteins, and its structural consequence and functional relevance.
CRITICAL ISSUES
Molecular mechanisms of folding remain under-studied and often disconnected from functional relevance.
FUTURE DIRECTIONS
The clinical benefit of redox research will require a comprehensive characterization of the various isoforms and paralogs of the redox enzymes and their concerted effect on the structure and function of the specific parasitic client proteins.
Topics: Animals; Models, Molecular; Oxidation-Reduction; Parasites; Protein Folding
PubMed: 22122448
DOI: 10.1089/ars.2011.4433 -
Journal of Clinical Microbiology Feb 2019Parasite taxonomy continues to change as molecular and morphologic studies enhance our understanding of parasite relatedness. This minireview builds on the information...
Parasite taxonomy continues to change as molecular and morphologic studies enhance our understanding of parasite relatedness. This minireview builds on the information provided in the last taxonomy update in this journal to summarize new and revised clinically relevant human parasite taxonomic changes that have occurred in 2016 and 2017.
Topics: Animals; Humans; Parasites; Parasitic Diseases; Parasitology
PubMed: 30282786
DOI: 10.1128/JCM.01067-18 -
Biomolecules Apr 2020Studies on the parasite-host interaction may provide valuable information concerning the modulation of molecular mechanisms as well as of the host immune system during... (Review)
Review
Studies on the parasite-host interaction may provide valuable information concerning the modulation of molecular mechanisms as well as of the host immune system during infection. To date, it has been demonstrated that intestinal parasites may affect, among others, the processes of digestion in the gastrointestinal system of the host, thus limiting the elimination of the parasite, the immune response as well as inflammation. However, the most recent studies suggest that intestinal parasites may also affect modulation of the apoptosis pathway of the host. The present paper presents the latest scientific information on the influence of intestinal parasite species ( sp., sp., sp., sp., , , ) on the molecular mechanisms of apoptosis in intestinal epithelial cells. This paper stresses that the interdependency between the intestinal parasite and the host results from the direct effect of the parasite and the host's defense reactions, which lead to modulation of the apoptosis pathways (intrinsic and extrinsic). Moreover, the present paper presents the role of proteins involved in the mechanisms of apoptosis as well as the physiological role of apoptosis in the host's intestinal epithelial cells.
Topics: Animals; Apoptosis; Enterocytes; Host-Parasite Interactions; Humans; Intestinal Diseases, Parasitic; Parasites
PubMed: 32349424
DOI: 10.3390/biom10050674 -
Cell Host & Microbe May 2016Protozoan parasites colonize numerous metazoan hosts and insect vectors through their life cycles, with the need to respond quickly and reversibly while encountering... (Review)
Review
Protozoan parasites colonize numerous metazoan hosts and insect vectors through their life cycles, with the need to respond quickly and reversibly while encountering diverse and often hostile ecological niches. To succeed, parasites must also persist within individuals until transmission between hosts is achieved. Several parasitic protozoa cause a huge burden of disease in humans and livestock, and here we focus on the parasites that cause malaria and African trypanosomiasis. Efforts to understand how these pathogens adapt to survive in varied host environments, cause disease, and transmit between hosts have revealed a wealth of epigenetic phenomena. Epigenetic switching mechanisms appear to be ideally suited for the regulation of clonal antigenic variation underlying successful parasitism. We review the molecular players and complex mechanistic layers that mediate the epigenetic regulation of virulence gene expression. Understanding epigenetic processes will aid the development of antiparasitic therapeutics.
Topics: Animals; Gene Expression Regulation; Humans; Parasites; Virulence
PubMed: 27173931
DOI: 10.1016/j.chom.2016.04.020 -
Trends in Parasitology Oct 2020The first experimental crosses carried out with the human malaria parasite Plasmodium falciparum played a key role in determining the genetic loci responsible for drug... (Review)
Review
The first experimental crosses carried out with the human malaria parasite Plasmodium falciparum played a key role in determining the genetic loci responsible for drug resistance, virulence, invasion, growth rate, and transmission. These crosses relied on splenectomized chimpanzees to complete the liver stage of the parasite's life cycle and the subsequent transition to asexual blood stage culture followed by cloning of recombinant progeny in vitro. Crosses can now be routinely carried out using human-liver-chimeric mice infused with human erythrocytes to generate hundreds of unique recombinant progeny for genetic linkage mapping, bulk segregant analysis, and high-throughput 'omics readouts. The high number of recombinant progeny should allow for unprecedented power and efficiency in the execution of a systems genetics approach to study P. falciparum biology.
Topics: Animals; Crosses, Genetic; Humans; Malaria, Falciparum; Mice; Parasitology; Plasmodium falciparum
PubMed: 32891493
DOI: 10.1016/j.pt.2020.07.009 -
Clinical Microbiology Reviews Jul 2002The in vitro culture of protozoan parasites involves highly complex procedures, which are subject to many variables. These parasites have very complex life cycles and,... (Review)
Review
The in vitro culture of protozoan parasites involves highly complex procedures, which are subject to many variables. These parasites have very complex life cycles and, depending on the life cycle stage, may require different culture parameters. However, in vitro cultivation is important for many reasons, some of which include: diagnosis, antigen and antibody production, assessment of parasite immune modulating capabilities, drug screening, improvements in chemotherapy, differentiation of clinical isolates, determination of strain differences, vaccine production, development of attenuated strains, and the continued supply of viable organisms for studying host-parasite interactions.
Topics: Animals; Culture Media; Eukaryota; Humans; Parasitology; Protozoan Infections
PubMed: 12097241
DOI: 10.1128/CMR.15.3.327-328.2002 -
Frontiers in Cellular and Infection... 2013There is a rapidly growing body of evidence that production of microvesicles (MVs) is a universal feature of cellular life. MVs can incorporate microRNA (miRNA), mRNA,... (Review)
Review
There is a rapidly growing body of evidence that production of microvesicles (MVs) is a universal feature of cellular life. MVs can incorporate microRNA (miRNA), mRNA, mtDNA, DNA and retrotransposons, camouflage viruses/viral components from immune surveillance, and transfer cargo between cells. These properties make MVs an essential player in intercellular communication. Increasing evidence supports the notion that MVs can also act as long-distance vehicles for RNA molecules and participate in metabolic synchronization and reprogramming eukaryotic cells including stem and germinal cells. MV ability to carry on DNA and their general distribution makes them attractive candidates for horizontal gene transfer, particularly between multi-cellular organisms and their parasites; this suggests important implications for the co-evolution of parasites and their hosts. In this review, we provide current understanding of the roles played by MVs in intracellular pathogens and parasitic infections. We also discuss the possible role of MVs in co-infection and host shifting.
Topics: Animals; Cell Communication; Exosomes; Host-Parasite Interactions; Humans; Parasites
PubMed: 24032108
DOI: 10.3389/fcimb.2013.00049 -
Current Biology : CB Jun 2022Parasitism has independently evolved multiple times across the entire tree of life, and there are numerous parasitic representatives from every major eukaryote kingdom....
Parasitism has independently evolved multiple times across the entire tree of life, and there are numerous parasitic representatives from every major eukaryote kingdom. In animals alone, parasitism has independently evolved at least 200 times. If there are any organisms that one might think would have access to limitless resources, it would be parasites. You would think that living in or on the body of their host, which serves as both a habitat and a food source, would provide parasites with bountiful resources to maximise every aspect of their existence, especially reproduction. But parasitism is not a loophole out of life history trade-offs. There is still a finite amount of resources that a parasite can obtain and allocate to its many needs. Living in a resource-rich environment has allowed many parasites to grow to sizes that are of multiple orders of magnitude larger than their free-living relatives. But that does not mean that the underlying economy of nature and its limitations are inapplicable to parasites.
Topics: Animals; Biological Evolution; Body Size; Host-Parasite Interactions; Parasites; Reproduction; Symbiosis
PubMed: 35728546
DOI: 10.1016/j.cub.2022.01.059