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Annual Review of Microbiology 2015Toxoplasmosis is the clinical and pathological consequence of acute infection with the obligate intracellular apicomplexan parasite Toxoplasma gondii. Symptoms result... (Review)
Review
Toxoplasmosis is the clinical and pathological consequence of acute infection with the obligate intracellular apicomplexan parasite Toxoplasma gondii. Symptoms result from tissue destruction that accompanies lytic parasite growth. This review updates current understanding of the host cell invasion, parasite replication, and eventual egress that constitute the lytic cycle, as well as the ways T. gondii manipulates host cells to ensure its survival. Since the publication of a previous iteration of this review 15 years ago, important advances have been made in our molecular understanding of parasite growth and mechanisms of host cell egress, and knowledge of the parasite's manipulation of the host has rapidly progressed. Here we cover molecular advances and current conceptual frameworks that include each of these topics, with an eye to what may be known 15 years from now.
Topics: Animals; Host-Parasite Interactions; Humans; Protozoan Proteins; Toxoplasma; Toxoplasmosis; Vacuoles
PubMed: 26332089
DOI: 10.1146/annurev-micro-091014-104100 -
Frontiers in Cellular and Infection... 2022In the age of big data an important question is how to ensure we make the most out of the resources we generate. In this review, we discuss the major methods used in... (Review)
Review
In the age of big data an important question is how to ensure we make the most out of the resources we generate. In this review, we discuss the major methods used in Apicomplexan and Kinetoplastid research to produce big datasets and advance our understanding of and biology. We debate the benefits and limitations of the current technologies, and propose future advancements that may be key to improving our use of these techniques. Finally, we consider the difficulties the field faces when trying to make the most of the abundance of data that has already been, and will continue to be, generated.
Topics: Big Data; Cryptosporidiosis; Cryptosporidium; Humans; Plasmodium; Toxoplasma
PubMed: 35734575
DOI: 10.3389/fcimb.2022.900878 -
International Journal For Parasitology Oct 2017Apicomplexan parasites such as Babesia, Theileria, Eimeria, Cryptosporidium and Toxoplasma greatly impact animal health globally, and improved, cost-effective measures... (Review)
Review
Apicomplexan parasites such as Babesia, Theileria, Eimeria, Cryptosporidium and Toxoplasma greatly impact animal health globally, and improved, cost-effective measures to control them are urgently required. These parasites have complex multi-stage life cycles including obligate intracellular stages. Major gaps in our understanding of the biology of these relatively poorly characterised parasites and the diseases they cause severely limit options for designing novel control methods. Here we review potentially important shared aspects of the biology of these parasites, such as cell invasion, host cell modification, and asexual and sexual reproduction, and explore the potential of the application of relatively well-established or newly emerging genetic manipulation methods, such as classical transfection or gene editing, respectively, for closing important gaps in our knowledge of the function of specific genes and proteins, and the biology of these parasites. In addition, genetic manipulation methods impact the development of novel methods of control of the diseases caused by these economically important parasites. Transient and stable transfection methods, in conjunction with whole and deep genome sequencing, were initially instrumental in improving our understanding of the molecular biology of apicomplexan parasites and paved the way for the application of the more recently developed gene editing methods. The increasingly efficient and more recently developed gene editing methods, in particular those based on the CRISPR/Cas9 system and previous conceptually similar techniques, are already contributing to additional gene function discovery using reverse genetics and related approaches. However, gene editing methods are only possible due to the increasing availability of in vitro culture, transfection, and genome sequencing and analysis techniques. We envisage that rapid progress in the development of novel gene editing techniques applied to apicomplexan parasites of veterinary interest will ultimately lead to the development of novel and more efficient methods for disease control.
Topics: Animals; Apicomplexa; CRISPR-Cas Systems; DNA Repair; Deoxyribonucleases; Gene Editing; Gene Knockout Techniques; Genome, Protozoan; Life Cycle Stages; Mutagenesis, Insertional; Protozoan Infections, Animal; Protozoan Vaccines; Transfection; Virulence Factors
PubMed: 28893636
DOI: 10.1016/j.ijpara.2017.08.002 -
Molecular Microbiology Jan 2018Parasites of the Apicomplexa phylum, such as Plasmodium spp. and Toxoplasma gondii, undergo complex life cycles involving multiple stages with distinct biology and... (Review)
Review
Parasites of the Apicomplexa phylum, such as Plasmodium spp. and Toxoplasma gondii, undergo complex life cycles involving multiple stages with distinct biology and morphologies. Post-translational modifications (PTMs), such as phosphorylation, acetylation and glycosylation, regulate numerous cellular processes, playing a role in every aspect of cell biology. PTMs can occur on proteins at any time in their lifespan and through alterations of target protein activity, localization, protein-protein interactions, among other functions, dramatically increase proteome diversity and complexity. In addition, PTMs can be induced or removed on changes in cellular environment and state. Thus, PTMs are likely to be key regulators of developmental transitions, biology and pathogenesis of apicomplexan parasites. In this review we examine the roles of PTMs in both parasite-specific and conserved eukaryotic processes, and the potential crosstalk between PTMs, that together regulate the intricate lives of these protozoa.
Topics: Acetylation; Amino Acid Sequence; Animals; Apicomplexa; Eukaryota; Glycosylation; Humans; Phosphorylation; Protein Processing, Post-Translational; Proteome; Proteomics; Protozoan Proteins; Toxoplasma
PubMed: 29052917
DOI: 10.1111/mmi.13867 -
Genetics Aug 2019Understanding the relatedness of individuals within or between populations is a common goal in biology. Increasingly, relatedness features in genetic epidemiology...
Understanding the relatedness of individuals within or between populations is a common goal in biology. Increasingly, relatedness features in genetic epidemiology studies of pathogens. These studies are relatively new compared to those in humans and other organisms, but are important for designing interventions and understanding pathogen transmission. Only recently have researchers begun to routinely apply relatedness to apicomplexan eukaryotic malaria parasites, and to date have used a range of different approaches on an basis. Therefore, it remains unclear how to compare different studies and which measures to use. Here, we systematically compare measures based on identity-by-state (IBS) and identity-by-descent (IBD) using a globally diverse data set of malaria parasites, and , and provide marker requirements for estimates based on IBD. We formally show that the informativeness of polyallelic markers for relatedness inference is maximized when alleles are equifrequent. Estimates based on IBS are sensitive to allele frequencies, which vary across populations and by experimental design. For portability across studies, we thus recommend estimates based on IBD. To generate estimates with errors below an arbitrary threshold of 0.1, we recommend ∼100 polyallelic or 200 biallelic markers. Marker requirements are immediately applicable to haploid malaria parasites and other haploid eukaryotes. C.I.s facilitate comparison when different marker sets are used. This is the first attempt to provide rigorous analysis of the reliability of, and requirements for, relatedness inference in malaria genetic epidemiology. We hope it will provide a basis for statistically informed prospective study design and surveillance strategies.
Topics: Genome, Protozoan; Models, Genetic; Pedigree; Phylogeny; Plasmodium falciparum; Plasmodium vivax; Polymorphism, Single Nucleotide
PubMed: 31209105
DOI: 10.1534/genetics.119.302120 -
Journal of Structural Biology May 2015The apicomplexan family of pathogens, which includes Plasmodium spp. and Toxoplasma gondii, are primarily obligate intracellular parasites and invade multiple cell... (Review)
Review
The apicomplexan family of pathogens, which includes Plasmodium spp. and Toxoplasma gondii, are primarily obligate intracellular parasites and invade multiple cell types. These parasites express extracellular membrane protein receptors, adhesins, to form specific pathogen-host cell interaction complexes. Various adhesins are used to invade a variety of cell types. The receptors are linked to an actomyosin motor, which is part of a complex comprised of many proteins known as the invasion machinery or glideosome. To date, reviews on invasion have focused primarily on the molecular pathways and signals of invasion, with little or no structural information presented. Over 75 structures of parasite receptors and glideosome proteins have been deposited with the Protein Data Bank. These structures include adhesins, motor proteins, bridging proteins, inner membrane complex and cytoskeletal proteins, as well as co-crystal structures with peptides and antibodies. These structures provide information regarding key interactions necessary for target receptor engagement, machinery complex formation, how force is transmitted, and the basis of inhibitory antibodies. Additionally, these structures can provide starting points for the development of antibodies and inhibitory molecules targeting protein-protein interactions, with the aim to inhibit invasion. This review provides an overview of the parasite adhesin protein families, the glideosome components, glideosome architecture, and discuss recent work regarding alternative models.
Topics: Actomyosin; Apicomplexa; Databases, Protein; Host-Pathogen Interactions; Membrane Proteins; Models, Molecular; Multiprotein Complexes; Protein Binding; Protein Conformation; Protein Interaction Mapping; Protein Structure, Tertiary
PubMed: 25764948
DOI: 10.1016/j.jsb.2015.02.008 -
Frontiers in Cellular and Infection... 2021
Topics: Animals; Apicomplexa; Gastrointestinal Tract; Host-Parasite Interactions; Invertebrates; Parasites; Vertebrates
PubMed: 33996642
DOI: 10.3389/fcimb.2021.680555 -
Parasites & Vectors Mar 2018Members of the genus Sarcocystis (Apicomplexa: Sarcocystidae) are intracellular protozoan parasites that infect a wide range of domestic and wild animals, resulting in... (Review)
Review
Members of the genus Sarcocystis (Apicomplexa: Sarcocystidae) are intracellular protozoan parasites that infect a wide range of domestic and wild animals, resulting in economic losses in production animals worldwide. Sarcocystis spp. have indirect life-cycles where canids and felids serve as main definitive hosts while a range of domestic and wild animals serve as intermediate hosts, including South American camelids (SACs) such as alpacas, llamas and guanacos. These animals primarily occur in South American countries on Andean, elevated plains but in recent years, alpacas and llamas have become emerging animal industries in other parts of the world such as Australia, Europe and the USA due to their high-quality fiber, meat and hides. For instance, alpaca meat is becoming popular in many parts of the world due to its lower cholesterol content than other red meat, thereby it has the potential of a valuable product for both local and international markets. However, SAC meat can be degraded and/or even condemned due to the presence of macroscopic sarcocysts in skeletal muscles, leading to significant economic losses to farmers. The infection is generally asymptomatic, though highly pathogenic or even fatal Sarcocystis infections have also been reported in alpacas and llamas. Despite the economic importance of sarcocystosis in SACs, little is known about the life-cycle of parasites involved, disease transmission, epidemiology, pathogenesis, diagnosis, control and public health significance. This review article provides an in-depth analysis of the existing knowledge on the taxonomy, epidemiology, clinicopathology and diagnosis of Sarcocystis in SACs, highlights knowledge gaps and proposes future areas of research that could contribute to our better understanding of sarcocystosis in these animals.
Topics: Animals; Animals, Domestic; Animals, Wild; Australia; Camelidae; Camelids, New World; Europe; Red Meat; Sarcocystis; Sarcocystosis; South America; United States
PubMed: 29510746
DOI: 10.1186/s13071-018-2748-1 -
Tick distribution and detection of Babesia and Theileria species in Eastern and Southern Kazakhstan.Ticks and Tick-borne Diseases Nov 2021Piroplasmosis is an economically important tick-borne disease worldwide. However, little is known about the presence of Babesia spp. and Theileria spp. in ticks in...
Piroplasmosis is an economically important tick-borne disease worldwide. However, little is known about the presence of Babesia spp. and Theileria spp. in ticks in Eastern and Southern Kazakhstan (ESK). During 2016 - 2019, adult ticks (at 26 sampling sites in 16 districts of 5 oblasts in ESK) were collected. Tick species were identified according to morphological and molecular characteristics. Two fragments (487 bp and 438 bp) of 18S ribosomal RNA (18S rRNA) were used to determine piroplasm species in representative 698 ticks. The genotype characteristics of Babesia caballi and Theileria equi were further analyzed by longer 18S rRNA gene fragments. A total of 6107 adult ticks (4558 parasitizing ticks and 1549 off-host ticks), including 4665 hard ticks and 1442 soft ticks, were collected from their natural hosts (cattle, horses, sheep, camels, shepherd dogs and hedgehogs) and the surrounding environment, respectively. Among the hard tick species, Dermacentor marginatus (62.59%, 2920/4665) was the most abundant, followed by Hyalomma asiaticum (19.36%, 903/4665) and Hyalomma detritum (9.95%, 464/4665). All soft ticks were identified as Argas persicus. 16S ribosomal DNA (16S rDNA) phylogenic analysis showed that several tick species in Kazakhstan, as exemplified by Haemaphysalis erinacei and D. marginatus, clustered together with conspecific ticks reported from China. Five species of piroplasms, i.e. Babesia occultans, Babesia caballi, Theileria ovis, Theileria annulata and Theileria equi, were detected in 698 representative ticks. Genotype E of T. equi in Almaty, and genotype A of B. caballi in Almaty and South Kazakhstan were identified.
Topics: Animals; Argasidae; Babesia; Genotype; Ixodidae; Kazakhstan; RNA, Protozoan; RNA, Ribosomal, 16S; RNA, Ribosomal, 18S; Species Specificity; Theileria
PubMed: 34560427
DOI: 10.1016/j.ttbdis.2021.101817 -
PLoS Pathogens Sep 2021
Topics: Animals; Anthozoa; Apicomplexa; Coral Reefs; Protozoan Infections
PubMed: 34529733
DOI: 10.1371/journal.ppat.1009845